Hydrolytic enzymes in sewage sludge treatment: a mini-review
- Burgess, Jo E, Pletschke, Brett I
- Authors: Burgess, Jo E , Pletschke, Brett I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6478 , http://hdl.handle.net/10962/d1006166 , http://hdl.handle.net/10520/EJC116535
- Description: Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
- Full Text:
- Date Issued: 2008
- Authors: Burgess, Jo E , Pletschke, Brett I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6478 , http://hdl.handle.net/10962/d1006166 , http://hdl.handle.net/10520/EJC116535
- Description: Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
- Full Text:
- Date Issued: 2008
The relationship between emergence of the shortest path and information value using ant-like agents
- Chibaya, Colin, Bangay, Shaun D
- Authors: Chibaya, Colin , Bangay, Shaun D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433318 , vital:72961 , https://doi.org/10.1145/1456659.1456663
- Description: Ant-like agents forage between two points. These agents' probabilistic movements are based on the use of two pheromones; one marking trails towards the goal and another marking trails back to the starting point. Path selection decisions are influenced by the relative levels of attractive and repulsive pheromone in each agent's local environment. Our work in [5] evaluates three pheromone perception strategies, investigating path formation speed, quality, directionality, robustness and adaptability under different parameter settings(degree of randomness, pheromone evaporation rate and pheromone diffusion rate).
- Full Text:
- Date Issued: 2008
- Authors: Chibaya, Colin , Bangay, Shaun D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433318 , vital:72961 , https://doi.org/10.1145/1456659.1456663
- Description: Ant-like agents forage between two points. These agents' probabilistic movements are based on the use of two pheromones; one marking trails towards the goal and another marking trails back to the starting point. Path selection decisions are influenced by the relative levels of attractive and repulsive pheromone in each agent's local environment. Our work in [5] evaluates three pheromone perception strategies, investigating path formation speed, quality, directionality, robustness and adaptability under different parameter settings(degree of randomness, pheromone evaporation rate and pheromone diffusion rate).
- Full Text:
- Date Issued: 2008
Automating the creation of 3D animation from annotated fiction text
- Glass, Kevin R, Bangay, Shaun D
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432639 , vital:72889 , https://www.iadisportal.org/digital-library/automating-the-creation-of-3d-animation-from-annotated-fiction-text
- Description: This paper describes a strategy for automatically converting fiction text into 3D animations. It assumes the existence of fiction text annotated with avatar, object, setting, transition and relation annotations, and presents a transformation process that converts annotated text into quantified constraint systems, the solutions to which are used in the population of 3D environments. Constraint solutions are valid over temporal intervals, ensuring that consistent dynamic behaviour is produced. A substantial level of automation is achieved, while providing opportunities for creative manual intervention in animation process. The process is demonstrated using annotated examples drawn from popular fiction text that are converted into animation sequences, confirming that the desired results can be achieved with only high-level human direction.
- Full Text:
- Date Issued: 2008
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432639 , vital:72889 , https://www.iadisportal.org/digital-library/automating-the-creation-of-3d-animation-from-annotated-fiction-text
- Description: This paper describes a strategy for automatically converting fiction text into 3D animations. It assumes the existence of fiction text annotated with avatar, object, setting, transition and relation annotations, and presents a transformation process that converts annotated text into quantified constraint systems, the solutions to which are used in the population of 3D environments. Constraint solutions are valid over temporal intervals, ensuring that consistent dynamic behaviour is produced. A substantial level of automation is achieved, while providing opportunities for creative manual intervention in animation process. The process is demonstrated using annotated examples drawn from popular fiction text that are converted into animation sequences, confirming that the desired results can be achieved with only high-level human direction.
- Full Text:
- Date Issued: 2008
Evaluating parts-of-speech taggers for use in a text-to-scene conversion system
- Glass, Kevin R, Bangay, Shaun D
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
Demand-side management of internet bandwidth
- Authors: Halse, Guy A
- Date: 2008
- Language: English
- Type: Conference paper
- Identifier: vital:6607 , http://hdl.handle.net/10962/d1009463
- Description: Presentation on the demand-side management of Internet bandwidth, using Rhodes University as a case study, as presented at the DITCHE national techie event in September 2008.
- Full Text:
- Date Issued: 2008
- Authors: Halse, Guy A
- Date: 2008
- Language: English
- Type: Conference paper
- Identifier: vital:6607 , http://hdl.handle.net/10962/d1009463
- Description: Presentation on the demand-side management of Internet bandwidth, using Rhodes University as a case study, as presented at the DITCHE national techie event in September 2008.
- Full Text:
- Date Issued: 2008
Viewpoint: reading conference recommendations in a wider context of social change
- Authors: Lotz-Sisitka, Heila
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67411 , vital:29085 , https://www.ajol.info/index.php/sajee/article/view/122783
- Description: publisher version , This short Viewpoint paper considers the role and value of conference recommendations in shaping the field of environmental education. It explores the social politics, and often contested nature, of conference recommendations and their institutional histories, arguing that the act of producing conference recommendations forms part of the practices of new social movements. The paper recommends historicising conference recommendations and OEcross readings‚ to consider changing discourses and new developments in the field. Accompanying the short Viewpoint paper, are two sets of recently produced conference recommendations, one from the 4th International Environmental Education Conference held in Ahmedabad, India, and the other from the 1st International Conference on Mainstreaming Environment and Sustainability in African Universities held in Nairobi, Kenya.
- Full Text:
- Date Issued: 2008
- Authors: Lotz-Sisitka, Heila
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67411 , vital:29085 , https://www.ajol.info/index.php/sajee/article/view/122783
- Description: publisher version , This short Viewpoint paper considers the role and value of conference recommendations in shaping the field of environmental education. It explores the social politics, and often contested nature, of conference recommendations and their institutional histories, arguing that the act of producing conference recommendations forms part of the practices of new social movements. The paper recommends historicising conference recommendations and OEcross readings‚ to consider changing discourses and new developments in the field. Accompanying the short Viewpoint paper, are two sets of recently produced conference recommendations, one from the 4th International Environmental Education Conference held in Ahmedabad, India, and the other from the 1st International Conference on Mainstreaming Environment and Sustainability in African Universities held in Nairobi, Kenya.
- Full Text:
- Date Issued: 2008
Baited traps may be an alternative to conventional pesticides in the integrated crop management of chicory (Compositae) in South Africa
- Midgley, John M, Hill, Martin P, Villet, Martin H
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6858 , http://hdl.handle.net/10962/d1011141 , http://dx.doi.org/10.1603/0022-0493(2008)101[99:BTMBAA]2.0.CO;2 , https://orcid.org/0000-0003-0579-5298
- Description: Chicory, Chicorium intybus L. (Compositae), is a major field crop in the Eastern Cape Province of South Africa. Several pests feed on the leaves of the plant, resulting in reduced yield. The most important of these are the noctuid moths Helicoverpa armigera (Hübner), Chrysodeixis acuta (Walker), and Trichoplusia orichalcea (F.). The use of attract-and-kill traps offers an alternative to broad-based insecticides in the control of these species. Three fields were treated with normal insecticides and three fields with yellow-baited traps. Eight additional traps were placed in each field, with half of the traps containing the insecticide 2,2-dichlorovinyl dimethyl phosphate (dichlorvos) and half without dichlorvos; and half yellow and half green. Total moth numbers and nonphytophage diversity were measured from these eight traps. Although no differences in H. armigera or T. orichalcea catches were observed between insecticide- and trap-treated fields, numbers of C. acuta and the total number of moths were significantly higher in insecticide-treated fields. Yellow traps containing dichlorvos contained more moths than yellow traps without dichlorvos, or green traps with dichlorvos, or green traps without dichlorvos; but they also contained more nonphytophagous insects. Yellow traps also enhanced the catches of thrips on card traps associated with them. These results offer an opportunity for the South African chicory industry to reduce pesticide applications and thus mitigate environmental impacts.
- Full Text:
- Date Issued: 2008
- Authors: Midgley, John M , Hill, Martin P , Villet, Martin H
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6858 , http://hdl.handle.net/10962/d1011141 , http://dx.doi.org/10.1603/0022-0493(2008)101[99:BTMBAA]2.0.CO;2 , https://orcid.org/0000-0003-0579-5298
- Description: Chicory, Chicorium intybus L. (Compositae), is a major field crop in the Eastern Cape Province of South Africa. Several pests feed on the leaves of the plant, resulting in reduced yield. The most important of these are the noctuid moths Helicoverpa armigera (Hübner), Chrysodeixis acuta (Walker), and Trichoplusia orichalcea (F.). The use of attract-and-kill traps offers an alternative to broad-based insecticides in the control of these species. Three fields were treated with normal insecticides and three fields with yellow-baited traps. Eight additional traps were placed in each field, with half of the traps containing the insecticide 2,2-dichlorovinyl dimethyl phosphate (dichlorvos) and half without dichlorvos; and half yellow and half green. Total moth numbers and nonphytophage diversity were measured from these eight traps. Although no differences in H. armigera or T. orichalcea catches were observed between insecticide- and trap-treated fields, numbers of C. acuta and the total number of moths were significantly higher in insecticide-treated fields. Yellow traps containing dichlorvos contained more moths than yellow traps without dichlorvos, or green traps with dichlorvos, or green traps without dichlorvos; but they also contained more nonphytophagous insects. Yellow traps also enhanced the catches of thrips on card traps associated with them. These results offer an opportunity for the South African chicory industry to reduce pesticide applications and thus mitigate environmental impacts.
- Full Text:
- Date Issued: 2008
Study of the formation of artifacts following Dichloromethane reaction with some nitrogenous drugs
- Mohammadi, Ali, Amini, Mohsen, Hamedani, Moteza P, Torkabadi, Hossein H, Walker, Roderick B
- Authors: Mohammadi, Ali , Amini, Mohsen , Hamedani, Moteza P , Torkabadi, Hossein H , Walker, Roderick B
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6409 , http://hdl.handle.net/10962/d1006495
- Description: In this work, the quaternization reaction of some nitrogenous drugs in dichloromethane under stress condition and room temperature at different times are studied. Under these conditions, drug-chloromethochloride adducts or artifacts were found to be formed for clozapine, ofloxacin and olanzapine. The structures of the resultant adducts were elucidated using 1H NMR spectroscopy. In addition, the amount of intact drug was determined using in-house validated HPLC methods with UV detection.
- Full Text:
- Date Issued: 2008
- Authors: Mohammadi, Ali , Amini, Mohsen , Hamedani, Moteza P , Torkabadi, Hossein H , Walker, Roderick B
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6409 , http://hdl.handle.net/10962/d1006495
- Description: In this work, the quaternization reaction of some nitrogenous drugs in dichloromethane under stress condition and room temperature at different times are studied. Under these conditions, drug-chloromethochloride adducts or artifacts were found to be formed for clozapine, ofloxacin and olanzapine. The structures of the resultant adducts were elucidated using 1H NMR spectroscopy. In addition, the amount of intact drug was determined using in-house validated HPLC methods with UV detection.
- Full Text:
- Date Issued: 2008
Factors affecting accuracy and precision of thermal summation models of insect development used to estimate post-mortem intervals
- Richards, Cameron S, Villet, Martin H
- Authors: Richards, Cameron S , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442142 , vital:73962 , https://doi.org/10.1007/s00414-008-0243-5
- Description: This paper investigates the effects that different summary statistics (minimum, median, mean, or maximum), temporal sampling resolutions (duration between sampling events), and sample sizes (number of individuals sampled per sampling event) had on the accuracy and precision of the regression coefficients of a typical thermal summation model used to calculate minimum post-mortem interval (PMI). No significant differences were found in the values of the developmental constants calculated from different summary statistics of the duration of development. Sample size was found to affect the precision of measurement of the duration of development but had little overall influence on thermal summation constant (K) and developmental threshold (D 0) calculations (and therefore, subsequent PMI estimates), but temporal sampling resolution had a direct influence on the accuracy of K and D 0 calculations. These data suggest that when numbers of experimental maggots are limited, it is more important to sample more frequently using smaller sample sizes than to sample less frequently with large sample sizes. Furthermore, we suggest that the median is the most representative summary measure of the duration of development and should be used preferentially.
- Full Text:
- Date Issued: 2008
- Authors: Richards, Cameron S , Villet, Martin H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442142 , vital:73962 , https://doi.org/10.1007/s00414-008-0243-5
- Description: This paper investigates the effects that different summary statistics (minimum, median, mean, or maximum), temporal sampling resolutions (duration between sampling events), and sample sizes (number of individuals sampled per sampling event) had on the accuracy and precision of the regression coefficients of a typical thermal summation model used to calculate minimum post-mortem interval (PMI). No significant differences were found in the values of the developmental constants calculated from different summary statistics of the duration of development. Sample size was found to affect the precision of measurement of the duration of development but had little overall influence on thermal summation constant (K) and developmental threshold (D 0) calculations (and therefore, subsequent PMI estimates), but temporal sampling resolution had a direct influence on the accuracy of K and D 0 calculations. These data suggest that when numbers of experimental maggots are limited, it is more important to sample more frequently using smaller sample sizes than to sample less frequently with large sample sizes. Furthermore, we suggest that the median is the most representative summary measure of the duration of development and should be used preferentially.
- Full Text:
- Date Issued: 2008
Women’s rights get a dressing down: mini skirt attacks in South Africa
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141888 , vital:38013 , DOI: 10.18848/1447-9508/cgp/v06i06/42462
- Description: On Sunday the 17th of February 2008 25-year old Nwabisa Ngcukana was stripped, paraded naked while more than 100 onlookers jeered and laughed, doused in alcohol and sexually assaulted by taxi drivers and hawkers at the Noord Street taxi rank in Johannesburg1 (The Star 2008: 2). She was the fourth woman to be assaulted in this way at the rank on that evening. Three other women were stripped and sexually assaulted at the same taxi rank on the previous day. In each of these cases the fact that the women were wearing mini skirts was cited as the reason for the attack.
- Full Text:
- Date Issued: 2008
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141888 , vital:38013 , DOI: 10.18848/1447-9508/cgp/v06i06/42462
- Description: On Sunday the 17th of February 2008 25-year old Nwabisa Ngcukana was stripped, paraded naked while more than 100 onlookers jeered and laughed, doused in alcohol and sexually assaulted by taxi drivers and hawkers at the Noord Street taxi rank in Johannesburg1 (The Star 2008: 2). She was the fourth woman to be assaulted in this way at the rank on that evening. Three other women were stripped and sexually assaulted at the same taxi rank on the previous day. In each of these cases the fact that the women were wearing mini skirts was cited as the reason for the attack.
- Full Text:
- Date Issued: 2008
Biological responses to a resumption in river flow in a freshwater-deprived, permanently open Southern African estuary
- Vorwerk, Paul D, Froneman, P William, Paterson, Angus W, Strydom, Nadine A, Whitfield, Alan K
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, Alan K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
- Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Strydom, Nadine A , Whitfield, Alan K
- Date: 2008
- Language: English
- Type: text , Article
- Identifier: vital:6886 , http://hdl.handle.net/10962/d1011645
- Description: The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as ‘the water required to protect the aquatic ecosystems of the water resource’) for this system.
- Full Text:
- Date Issued: 2008
A tuple space web service for distributed programming-Simplifying distributed web services applications
- Wells, George C, Mueller, Barbara, Schulé, Lo¨ıc
- Authors: Wells, George C , Mueller, Barbara , Schulé, Lo¨ıc
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430437 , vital:72691 , https://www.scitepress.org/PublishedPapers/2008/15170/15170.pdf
- Description: This paper describes a new tuple space web service for coordination and communication in distributed web applications. This web service is based on the Linda programming model. Linda is a coordination lan-guage for parallel and distributed processing, providing a communica-tion mechanism based on a logically shared memory space. The origi-nal Linda model has been extended through the provision of a pro-grammable mechanism, providing additional flexibility and improved performance. The implementation of the web service is discussed, to-gether with the details of the programmable matching mechanism. Some results from the implementation of a location-based mobile appli-cation, using the tuple space web service are presented, demonstrating the benefits of our system.
- Full Text:
- Date Issued: 2008
- Authors: Wells, George C , Mueller, Barbara , Schulé, Lo¨ıc
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430437 , vital:72691 , https://www.scitepress.org/PublishedPapers/2008/15170/15170.pdf
- Description: This paper describes a new tuple space web service for coordination and communication in distributed web applications. This web service is based on the Linda programming model. Linda is a coordination lan-guage for parallel and distributed processing, providing a communica-tion mechanism based on a logically shared memory space. The origi-nal Linda model has been extended through the provision of a pro-grammable mechanism, providing additional flexibility and improved performance. The implementation of the web service is discussed, to-gether with the details of the programmable matching mechanism. Some results from the implementation of a location-based mobile appli-cation, using the tuple space web service are presented, demonstrating the benefits of our system.
- Full Text:
- Date Issued: 2008
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