The use of response surface methodology to evaluate the impact of level 2 SUPAC–IR changes on the in vitro release of metronidazole and ranitidine from a fixed-dose combination tablet
- King’ori, Loti D, Walker, Roderick B
- Authors: King’ori, Loti D , Walker, Roderick B
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6391 , http://hdl.handle.net/10962/d1006313
- Description: The purpose of this study was to evaluate the effect of different levels of disintegrant (croscarmellose sodium, CCS), binder (polyvinylprrolidone K30, PVP–K30), and lubricant (magnesium stearate) on the in vitro release of metronidazole (MTZ) and rantidine (RTD) from a solid oral fixed-dose combination tablet. The excipient levels investigated were Level 2 changes in component and composition described in the Scale-Up and Post Approval Changes for Immediate Release (SUPAC–IR) guidance (1). Batches of tablets (1000 units) were manufactured by wet granulation using a Saral high-shear mixer granulator and a Manesty B3B rotary tablet press. Weight uniformity, friability, and disintegration of all tablets were assessed, and all batches complied with compendial specifications. The amount of drug released (Q) at ten minutes was dependent on the levels of CCS in the formulation, and the effect of PVP–K30 and magnesium stearate was dependent on the levels of CCS. Synergistic interactions between independent variables were observed for the Q10 value for RTD, whereas PVP–K30 and magnesium stearate exhibited an antagonistic effect on the Q10 values for MTZ and RTD. The use of response surface methodology facilitated an investigation into the effect of Level 2 component and composition changes, as described in SUPAC–IR, on the in vitro release of MTZ and RTD from a fixed-dose combination (FDC) solid oral dosage form (SODF).
- Full Text:
- Date Issued: 2012
- Authors: King’ori, Loti D , Walker, Roderick B
- Date: 2012
- Language: English
- Type: text , Article
- Identifier: vital:6391 , http://hdl.handle.net/10962/d1006313
- Description: The purpose of this study was to evaluate the effect of different levels of disintegrant (croscarmellose sodium, CCS), binder (polyvinylprrolidone K30, PVP–K30), and lubricant (magnesium stearate) on the in vitro release of metronidazole (MTZ) and rantidine (RTD) from a solid oral fixed-dose combination tablet. The excipient levels investigated were Level 2 changes in component and composition described in the Scale-Up and Post Approval Changes for Immediate Release (SUPAC–IR) guidance (1). Batches of tablets (1000 units) were manufactured by wet granulation using a Saral high-shear mixer granulator and a Manesty B3B rotary tablet press. Weight uniformity, friability, and disintegration of all tablets were assessed, and all batches complied with compendial specifications. The amount of drug released (Q) at ten minutes was dependent on the levels of CCS in the formulation, and the effect of PVP–K30 and magnesium stearate was dependent on the levels of CCS. Synergistic interactions between independent variables were observed for the Q10 value for RTD, whereas PVP–K30 and magnesium stearate exhibited an antagonistic effect on the Q10 values for MTZ and RTD. The use of response surface methodology facilitated an investigation into the effect of Level 2 component and composition changes, as described in SUPAC–IR, on the in vitro release of MTZ and RTD from a fixed-dose combination (FDC) solid oral dosage form (SODF).
- Full Text:
- Date Issued: 2012
Towards empowering learners in a democratic mathematics classroom: to what extent are teachers' listening orientations conducive to and respectful of learners' thinking?
- Mhlolo, Michael K, Schäfer, Marc
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140882 , vital:37926 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC129235
- Description: In an effort to make education accessible, to 'heal the divisions of the past and establish a society based on democratic values', the South African Department of Education claims that a series of mathematics reforms that has so far been introduced is underpinned by the principles of 'social justice, fundamental human rights and inclusivity'. Critics however argue that the system has remained 'undemocratic' in that those groups of learners who were supposed to be 'healed' continue to underperform and hence be disempowered. In this study, we conceptualised a democratic and mathematically empowering classroom as one that is consistent with the principle of inclusivity and in which a hermeneutic listening orientation towards teaching promotes such a democratic and mathematically empowering learning environment. We then worked with three different orientations teachers might have towards listening in the mathematics classroom: evaluative, interpretive and hermeneutic. We then used these orientations to analyse 20 video-recorded lessons with a specific focus on learners' unexpected contributions and how teachers listened and responded to such contributions. The results were consistent with the literature, which shows that teachers tend to dismiss learners' ways of thinking by imposing their own formalised constructions.
- Full Text:
- Date Issued: 2012
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140882 , vital:37926 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC129235
- Description: In an effort to make education accessible, to 'heal the divisions of the past and establish a society based on democratic values', the South African Department of Education claims that a series of mathematics reforms that has so far been introduced is underpinned by the principles of 'social justice, fundamental human rights and inclusivity'. Critics however argue that the system has remained 'undemocratic' in that those groups of learners who were supposed to be 'healed' continue to underperform and hence be disempowered. In this study, we conceptualised a democratic and mathematically empowering classroom as one that is consistent with the principle of inclusivity and in which a hermeneutic listening orientation towards teaching promotes such a democratic and mathematically empowering learning environment. We then worked with three different orientations teachers might have towards listening in the mathematics classroom: evaluative, interpretive and hermeneutic. We then used these orientations to analyse 20 video-recorded lessons with a specific focus on learners' unexpected contributions and how teachers listened and responded to such contributions. The results were consistent with the literature, which shows that teachers tend to dismiss learners' ways of thinking by imposing their own formalised constructions.
- Full Text:
- Date Issued: 2012
Enhancing the Configuration and Design of Sound Systems through Simulation
- Otten, Frederick, Foss, Richard
- Authors: Otten, Frederick , Foss, Richard
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427125 , vital:72416 , https://www.aes.org/e-lib/browse.cfm?elib=15848
- Description: Audio Engineers are required to design and deploy large multi-channel sound systems which meet a set of requirements and use networking technologies such as Firewire and Ethernet. Bandwidth utilsation and latency need to be considered. Network Simulation can be used to accurately model a network and return such information. This paper discusses a software system which has been developed to create a simulation of a network using the AES-X170 protocol for command and control. This system shows information about bandwidth and latency and is able to detect problems with parameter relationships. It also provides the ability to perform offline editing. These features significantly enhance audio engineers' ability to effectively design, configure and evaluate sound systems.
- Full Text:
- Date Issued: 2011
- Authors: Otten, Frederick , Foss, Richard
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427125 , vital:72416 , https://www.aes.org/e-lib/browse.cfm?elib=15848
- Description: Audio Engineers are required to design and deploy large multi-channel sound systems which meet a set of requirements and use networking technologies such as Firewire and Ethernet. Bandwidth utilsation and latency need to be considered. Network Simulation can be used to accurately model a network and return such information. This paper discusses a software system which has been developed to create a simulation of a network using the AES-X170 protocol for command and control. This system shows information about bandwidth and latency and is able to detect problems with parameter relationships. It also provides the ability to perform offline editing. These features significantly enhance audio engineers' ability to effectively design, configure and evaluate sound systems.
- Full Text:
- Date Issued: 2011
Network neutral control over quality of service networks
- Foulkes, Phillip, Foss, Richard, Gurdan, Robby
- Authors: Foulkes, Phillip , Foss, Richard , Gurdan, Robby
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427166 , vital:72419 , https://www.aes.org/e-lib/online/browse.cfm?elib=16151
- Description: Creating interoperability between two standards-based network technologies, IEEE 1394 Firewire and Ethernet Audio/Video Bridging (AVB), allows them to exist simultaneously in a single application configuration. While both technologies provide the transport of synchronized, low-latency, real-time audio and video data, they have different approaches to enabling this transport. By using a compatible audio gateway with a common control protocol, audio devices on these disparate networks can be connected and controlled.
- Full Text:
- Date Issued: 2011
- Authors: Foulkes, Phillip , Foss, Richard , Gurdan, Robby
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427166 , vital:72419 , https://www.aes.org/e-lib/online/browse.cfm?elib=16151
- Description: Creating interoperability between two standards-based network technologies, IEEE 1394 Firewire and Ethernet Audio/Video Bridging (AVB), allows them to exist simultaneously in a single application configuration. While both technologies provide the transport of synchronized, low-latency, real-time audio and video data, they have different approaches to enabling this transport. By using a compatible audio gateway with a common control protocol, audio devices on these disparate networks can be connected and controlled.
- Full Text:
- Date Issued: 2011
The PINIT domain of PIAS3: structure-function analysis of its interaction with STAT3
- Mautsa, Nicodemus, Prinsloo, Earl, Tastan Bishop, Özlem, Blatch, Gregory L
- Authors: Mautsa, Nicodemus , Prinsloo, Earl , Tastan Bishop, Özlem , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148082 , vital:38708 , DOI: 10.1002/jmr.1111
- Description: The protein inhibitor of activated signal transducer and activator of transcription 3 (PIAS3) regulates the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) which regulates transcription of genes involved in cell growth, proliferation and apoptosis. The conserved proline, isoleucine, asparagine, isoleucine, threonine (PINIT) domain of PIAS3 is thought to promote STAT3–PIAS3 interaction.
- Full Text:
- Date Issued: 2011
- Authors: Mautsa, Nicodemus , Prinsloo, Earl , Tastan Bishop, Özlem , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148082 , vital:38708 , DOI: 10.1002/jmr.1111
- Description: The protein inhibitor of activated signal transducer and activator of transcription 3 (PIAS3) regulates the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) which regulates transcription of genes involved in cell growth, proliferation and apoptosis. The conserved proline, isoleucine, asparagine, isoleucine, threonine (PINIT) domain of PIAS3 is thought to promote STAT3–PIAS3 interaction.
- Full Text:
- Date Issued: 2011
The xfn connection management and control protocol
- Foss, Richard, Gurdan, Robby, Klinkradt, Bradley, Chigwamba, Nyasha
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427137 , vital:72417 , https://www.aes.org/e-lib/browse.cfm?elib=16143
- Description: With the advent of digital networks that link audio devices, there is a need for a protocol that integrates control and connection management, enables the streaming of all media content such as audio and video between devices from different manufacturers, and that provides a common approach to the control of these devices. This paper describes such a protocol, named XFN, currently being standardized as part of the AES X170 project. XFN is an IP-based peer to peer network protocol, in which any device on the network may send or receive connection management, control, and monitoring messages. Essential to the XFN protocol is the fact that each parameter in a device can be addressed via a hierarchical structure that reflects the functional layout of the device.
- Full Text:
- Date Issued: 2011
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427137 , vital:72417 , https://www.aes.org/e-lib/browse.cfm?elib=16143
- Description: With the advent of digital networks that link audio devices, there is a need for a protocol that integrates control and connection management, enables the streaming of all media content such as audio and video between devices from different manufacturers, and that provides a common approach to the control of these devices. This paper describes such a protocol, named XFN, currently being standardized as part of the AES X170 project. XFN is an IP-based peer to peer network protocol, in which any device on the network may send or receive connection management, control, and monitoring messages. Essential to the XFN protocol is the fact that each parameter in a device can be addressed via a hierarchical structure that reflects the functional layout of the device.
- Full Text:
- Date Issued: 2011
Towards a standard model for networked audio devices
- Eales, Andrew, Foss, Richard
- Authors: Eales, Andrew , Foss, Richard
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427151 , vital:72418 , https://www.aes.org/e-lib/online/browse.cfm?elib=16144
- Description: Different control protocols for networked audio devices typically emphasize particular aspects of a device, such as the representation of parameter data, or a representation of the functional structure of a device. A sophisticated device model must represent parameter data, device structure and the visual presentation of controls. Parameter data should be related to the device structure, while also being represented within a flexible, logical hierarchy. The development of a standard device model is proposed and discussed with reference to the OSC, IEC62379, ACN and X170 control protocols. This abstract model is independent of any specific control protocol, and provides support for interoperability between control protocols. The proposed model is also discussed within the context of an object-based approach to service enumeration and control using an associative, shared memory model.
- Full Text:
- Date Issued: 2011
- Authors: Eales, Andrew , Foss, Richard
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427151 , vital:72418 , https://www.aes.org/e-lib/online/browse.cfm?elib=16144
- Description: Different control protocols for networked audio devices typically emphasize particular aspects of a device, such as the representation of parameter data, or a representation of the functional structure of a device. A sophisticated device model must represent parameter data, device structure and the visual presentation of controls. Parameter data should be related to the device structure, while also being represented within a flexible, logical hierarchy. The development of a standard device model is proposed and discussed with reference to the OSC, IEC62379, ACN and X170 control protocols. This abstract model is independent of any specific control protocol, and provides support for interoperability between control protocols. The proposed model is also discussed within the context of an object-based approach to service enumeration and control using an associative, shared memory model.
- Full Text:
- Date Issued: 2011
When breast is not best: young women and breast reduction surgery
- Lamb, Tessa, Vincent, Louise
- Authors: Lamb, Tessa , Vincent, Louise
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141832 , vital:38008 , DOI: 10.1080/10130950.2011.610978
- Description: Most cosmetic surgery patients in South Africa are younger than 21, and in this focus we examine narrative accounts from young South African women who have chosen to undergo cosmetic breast reduction surgery. Feminist debates on cosmetic surgery have focused on the question of whether to regard women who modify their bodies in this way as active agents engaged in liberatory ‘body projects’, or whether such projects are evidence of their subjection to oppressive stereotypes and beauty norms. The latter perspective is challenged here by the participants’ characterisation of breast reduction surgery as profoundly ‘freeing’. The article deals in particular with the conscious choice of participants to knowingly risk not being able to breastfeed children in future in order to achieve a body type which conforms to their understanding of youthful beauty and sexuality.
- Full Text:
- Date Issued: 2011
- Authors: Lamb, Tessa , Vincent, Louise
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141832 , vital:38008 , DOI: 10.1080/10130950.2011.610978
- Description: Most cosmetic surgery patients in South Africa are younger than 21, and in this focus we examine narrative accounts from young South African women who have chosen to undergo cosmetic breast reduction surgery. Feminist debates on cosmetic surgery have focused on the question of whether to regard women who modify their bodies in this way as active agents engaged in liberatory ‘body projects’, or whether such projects are evidence of their subjection to oppressive stereotypes and beauty norms. The latter perspective is challenged here by the participants’ characterisation of breast reduction surgery as profoundly ‘freeing’. The article deals in particular with the conscious choice of participants to knowingly risk not being able to breastfeed children in future in order to achieve a body type which conforms to their understanding of youthful beauty and sexuality.
- Full Text:
- Date Issued: 2011
A histological description of ovarian recrudescence in two Labeo victorianus populations
- Booth, Anthony J, Hecht, Thomas
- Authors: Booth, Anthony J , Hecht, Thomas
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123564 , vital:35455 , https://doi.org/10.2989/16085910409503813
- Description: The ovaries of Labeo victorianus are paired organs situated in the peritoneal cavity and suspended on either side of the midline by a mesovarium. A capsule, composed of dense, regularly-arranged collagen and elastic fibres mixed with a few smooth muscle cells, enclosed the ovaries and gave off connective tissue septa, forming the ovigerous lamellae, which contained germ and follicle cells. Eight discrete stages of recrudescence were identified: oogonia, chromatin nucleolar oocytes, perinucleolar oocytes, primary yolk vesicle oocytes, secondary yolk vesicle oocytes, tertiary yolk vesicle oocytes, post-ovulatory follicles and atretic oocytes. Ovulation seemed to be synchronised with the onset of rainfall, with some deviations in the Sio River population. Gonadosomatic index variation followed a bimodal pattern, with maxima between January–February and between September–October for both populations. The same pattern was exhibited for both rainfall and water levels at the two study sites. Successful ovulation was followed by the formation of post-ovulatory follicles and Type I atresia, while failed spawning was characterised by Type II atresia. Clearance of post-ovulatory follicles was by phagocytosis and formation of melanomacrophage centres. There were variations in post-ovulatory changes between the two populations. Reproductive patterns in the Kagera River population conformed to the ‘norm’ in African labeines of the synchronisation of spawning with rainfall. Slight deviations from this pattern were, however, observed in the Sio River population where spawning occurred prior to the onset of rainfall.
- Full Text:
- Date Issued: 2010
- Authors: Booth, Anthony J , Hecht, Thomas
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123564 , vital:35455 , https://doi.org/10.2989/16085910409503813
- Description: The ovaries of Labeo victorianus are paired organs situated in the peritoneal cavity and suspended on either side of the midline by a mesovarium. A capsule, composed of dense, regularly-arranged collagen and elastic fibres mixed with a few smooth muscle cells, enclosed the ovaries and gave off connective tissue septa, forming the ovigerous lamellae, which contained germ and follicle cells. Eight discrete stages of recrudescence were identified: oogonia, chromatin nucleolar oocytes, perinucleolar oocytes, primary yolk vesicle oocytes, secondary yolk vesicle oocytes, tertiary yolk vesicle oocytes, post-ovulatory follicles and atretic oocytes. Ovulation seemed to be synchronised with the onset of rainfall, with some deviations in the Sio River population. Gonadosomatic index variation followed a bimodal pattern, with maxima between January–February and between September–October for both populations. The same pattern was exhibited for both rainfall and water levels at the two study sites. Successful ovulation was followed by the formation of post-ovulatory follicles and Type I atresia, while failed spawning was characterised by Type II atresia. Clearance of post-ovulatory follicles was by phagocytosis and formation of melanomacrophage centres. There were variations in post-ovulatory changes between the two populations. Reproductive patterns in the Kagera River population conformed to the ‘norm’ in African labeines of the synchronisation of spawning with rainfall. Slight deviations from this pattern were, however, observed in the Sio River population where spawning occurred prior to the onset of rainfall.
- Full Text:
- Date Issued: 2010
A Proxy Approach for Interoperability and Common Control of Networked Digital Audio Devices
- Igumbor, Osedum P, Foss, Richard
- Authors: Igumbor, Osedum P , Foss, Richard
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427099 , vital:72414 , https://www.aes.org/e-lib/browse.cfm?elib=15338
- Description: This paper highlights the challenge that results from the availability of a large number of control protocols within the context of digital audio networks. Devices that conform to different protocols are unable to communicate with one another, even though they might be utilizing the same networking technology (Ethernet, IEEE 1394 serial bus, USB). This paper describes the use of a proxy that allows for high-level device interaction (by sending protocol messages) between networked devices. Furthermore, the proxy allows for a common controller to control the disparate networked devices.
- Full Text:
- Date Issued: 2010
- Authors: Igumbor, Osedum P , Foss, Richard
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427099 , vital:72414 , https://www.aes.org/e-lib/browse.cfm?elib=15338
- Description: This paper highlights the challenge that results from the availability of a large number of control protocols within the context of digital audio networks. Devices that conform to different protocols are unable to communicate with one another, even though they might be utilizing the same networking technology (Ethernet, IEEE 1394 serial bus, USB). This paper describes the use of a proxy that allows for high-level device interaction (by sending protocol messages) between networked devices. Furthermore, the proxy allows for a common controller to control the disparate networked devices.
- Full Text:
- Date Issued: 2010
Does reservoir trophic status influence the feeding and growth of the sharptooth catfish, Clarias gariepinus (Teleostei: Clariidae)?
- Potts, Warren M, Hecht, Thomas, Andrew, Timothy G
- Authors: Potts, Warren M , Hecht, Thomas , Andrew, Timothy G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124309 , vital:35591 , https://doi.org/10.2989/A JAS.2008.33.2.6.503
- Description: The diet and growth of sharptooth catfish, Clarias gariepinus, in an oligotrophic system (Kat River Reservoir, Eastern Cape, South Africa) were compared to those in a eutrophic system (Laing Reservoir, Eastern Cape) to determine if the trophic status of a waterbody had an effect on the growth rate of the species. In order of importance, the diet of catfish in Kat River Reservoir consisted of fish, insects, zooplankton, plant material and other items, while the diet of catfish in Laing Reservoir consisted of fish, plant material, zooplankton, other vertebrates and insects. The diets of catfish in the two reservoirs had a similarity index of 68.1% and there was no significant difference in their nutritional value. Fish prey was the most important dietary component in both reservoirs. Temperature regime and zooplankton and zoobenthos density were similar in both systems. However, fish prey density was significantly higher in the eutrophic Laing Reservoir and catfish grew significantly faster in that system. The slower growth rate in Kat River Reservoir was attributed to the higher energy costs associated with the capture of fish prey, which was less abundant than in Laing Reservoir. Trophic status therefore had an indirect effect on catfish growth by influencing the availability of fish prey.
- Full Text:
- Date Issued: 2010
- Authors: Potts, Warren M , Hecht, Thomas , Andrew, Timothy G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124309 , vital:35591 , https://doi.org/10.2989/A JAS.2008.33.2.6.503
- Description: The diet and growth of sharptooth catfish, Clarias gariepinus, in an oligotrophic system (Kat River Reservoir, Eastern Cape, South Africa) were compared to those in a eutrophic system (Laing Reservoir, Eastern Cape) to determine if the trophic status of a waterbody had an effect on the growth rate of the species. In order of importance, the diet of catfish in Kat River Reservoir consisted of fish, insects, zooplankton, plant material and other items, while the diet of catfish in Laing Reservoir consisted of fish, plant material, zooplankton, other vertebrates and insects. The diets of catfish in the two reservoirs had a similarity index of 68.1% and there was no significant difference in their nutritional value. Fish prey was the most important dietary component in both reservoirs. Temperature regime and zooplankton and zoobenthos density were similar in both systems. However, fish prey density was significantly higher in the eutrophic Laing Reservoir and catfish grew significantly faster in that system. The slower growth rate in Kat River Reservoir was attributed to the higher energy costs associated with the capture of fish prey, which was less abundant than in Laing Reservoir. Trophic status therefore had an indirect effect on catfish growth by influencing the availability of fish prey.
- Full Text:
- Date Issued: 2010
Factors affecting recapture rates of raggedtooth sharks Carcharias taurus tagged off the east coast of South Africa
- Dicken, Matthew L, Booth, Anthony J, Smale, Malcolm J
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124493 , vital:35618 , https://doi.10.2989/AJMS.2009.31.3.9.997
- Description: Understanding differences in the recapture rate between different tags (A-, B- and C-types), capture methods (rock-and-surf anglers, scientific divers and Natal Sharks Board protection nets) and life-history stages (juvenile and adult) is critical in evaluating the results obtained from cooperative tagging programmes (CTPs). A generalised linear modelling approach, using a log-linear model, was used to determine significant differences in the probability of recapture between these various factors using data from the Oceanographic Research Institute and Port Elizabeth Museum CTPs. Between 1984 and 2004, a total of 3 385 raggedtooth sharks Carcharias taurus was tagged by volunteers from both programmes along the east coast of South Africa. A likelihood ratio test indicated significant differences in the probability of recapture between A- and C-type and B- and C-type tags (p < 0.01), between different capture methods (p < 0.05) and between juvenile and adult sharks (p < 0.01). A comparison of recapture rates between members of the CTPs also indicated a marked variability in the performance of individual taggers. The study highlights important data-quality issues inherent in large CTPs.
- Full Text:
- Date Issued: 2010
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124493 , vital:35618 , https://doi.10.2989/AJMS.2009.31.3.9.997
- Description: Understanding differences in the recapture rate between different tags (A-, B- and C-types), capture methods (rock-and-surf anglers, scientific divers and Natal Sharks Board protection nets) and life-history stages (juvenile and adult) is critical in evaluating the results obtained from cooperative tagging programmes (CTPs). A generalised linear modelling approach, using a log-linear model, was used to determine significant differences in the probability of recapture between these various factors using data from the Oceanographic Research Institute and Port Elizabeth Museum CTPs. Between 1984 and 2004, a total of 3 385 raggedtooth sharks Carcharias taurus was tagged by volunteers from both programmes along the east coast of South Africa. A likelihood ratio test indicated significant differences in the probability of recapture between A- and C-type and B- and C-type tags (p < 0.01), between different capture methods (p < 0.05) and between juvenile and adult sharks (p < 0.01). A comparison of recapture rates between members of the CTPs also indicated a marked variability in the performance of individual taggers. The study highlights important data-quality issues inherent in large CTPs.
- Full Text:
- Date Issued: 2010
Growth, reproduction and population structure of Diplotaxodon limnothrissa in the southeast arm of Lake Malawi
- Kanyerere, Geoffrey Z, Weyl, Olaf L F, Booth, Anthony J
- Authors: Kanyerere, Geoffrey Z , Weyl, Olaf L F , Booth, Anthony J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124583 , vital:35633 , https://doi.org/10.2989/16085910509503832
- Description: With a surface area of ca 28 800km2, Lake Malawi (9°30’S–14°30’S) is the second largest of the African Rift Valley lakes, supporting at least 500, and possibly 2 000, fish species (Turner 1995). The ichthyofauna is dominated by haplochomine cichlids, most of which are confined to the demersal and littoral zones. As a result of over-fishing, the abundance of many of these species has declined (Turner 1994a, 1995, Bulirani et al. 1999, Allison et al. 2002). In contrast, the lake’s offshore fish stocks are considered to be unexploited or only lightly exploited (Thompson and Allison 1997, Turner et al. 2000) and the redirection of fishing effort to these stocks is a high priority (Thompson and Allison 1997, Turner et al. 2000, Allison et al. 2002). Consequently, the Malawi government is currently collaborating with the African Development Bank to develop the deepwater/ offshore fishery in order to increase yields by an estimated 11 000 tons (MC Banda, National Research co-ordinator, pers. comm.). The most abundant cichlid species in the pelagic zone is the small (<210mm TL) zooplanktivorous Diplotaxodon limnothrissa (Turner 1994, Thompson and Allison 1997). It has been recorded throughout the lake at depths ranging from 20 metres down to the anoxic zone at ca 220 metres (Turner 1994b, Thompson et al. 1996, Duponchelle et al. 2000a) and it makes up ca 52% to the total fish biomass (Thompson and Allison 1997). Diplotaxodon limnothrissa will therefore be a major target species in the pelagic fishery, and already comprises in excess of 50% of the mid-water trawl fishery in the southeast arm (SEA) of the lake (Turner 1996).
- Full Text:
- Date Issued: 2010
- Authors: Kanyerere, Geoffrey Z , Weyl, Olaf L F , Booth, Anthony J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124583 , vital:35633 , https://doi.org/10.2989/16085910509503832
- Description: With a surface area of ca 28 800km2, Lake Malawi (9°30’S–14°30’S) is the second largest of the African Rift Valley lakes, supporting at least 500, and possibly 2 000, fish species (Turner 1995). The ichthyofauna is dominated by haplochomine cichlids, most of which are confined to the demersal and littoral zones. As a result of over-fishing, the abundance of many of these species has declined (Turner 1994a, 1995, Bulirani et al. 1999, Allison et al. 2002). In contrast, the lake’s offshore fish stocks are considered to be unexploited or only lightly exploited (Thompson and Allison 1997, Turner et al. 2000) and the redirection of fishing effort to these stocks is a high priority (Thompson and Allison 1997, Turner et al. 2000, Allison et al. 2002). Consequently, the Malawi government is currently collaborating with the African Development Bank to develop the deepwater/ offshore fishery in order to increase yields by an estimated 11 000 tons (MC Banda, National Research co-ordinator, pers. comm.). The most abundant cichlid species in the pelagic zone is the small (<210mm TL) zooplanktivorous Diplotaxodon limnothrissa (Turner 1994, Thompson and Allison 1997). It has been recorded throughout the lake at depths ranging from 20 metres down to the anoxic zone at ca 220 metres (Turner 1994b, Thompson et al. 1996, Duponchelle et al. 2000a) and it makes up ca 52% to the total fish biomass (Thompson and Allison 1997). Diplotaxodon limnothrissa will therefore be a major target species in the pelagic fishery, and already comprises in excess of 50% of the mid-water trawl fishery in the southeast arm (SEA) of the lake (Turner 1996).
- Full Text:
- Date Issued: 2010
Identifying annotations for adventure game generation from fiction text
- Berkland, Ross, Bangay, Shaun D
- Authors: Berkland, Ross , Bangay, Shaun D
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433366 , vital:72965 , https://doi.org/10.1145/1899503.1899506
- Description: Recent advancements in Text-to-Scene research have lead to the devel-opment of systems which automatically extract key concepts from the text of a fiction book and generate computer animated movies depicting the sto-ry. Extracting such annotations from raw fiction text is a laborious process and so in this work we evaluate appropriate candidates to serve as the basis for the required annotations for generating interactive virtual worlds. We val-idate our choice by generating adventure games: interactive virtual worlds which create a stylized representation of the environment described in the text, populate it with characters related to the story and define game goals related to the plot of the fiction story. Our prototype produces a fully playa-ble game, making use of an existing open-source game engine. The pro-cess is evaluated using user tests in which participants are asked to meas-ure the accuracy with which the game represents the events, characters and goals described in the story. The response indicates that the chosen an-notation set is sufficient to define a game that is a plausibly acceptable rep-resentation of the text.
- Full Text:
- Date Issued: 2010
- Authors: Berkland, Ross , Bangay, Shaun D
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433366 , vital:72965 , https://doi.org/10.1145/1899503.1899506
- Description: Recent advancements in Text-to-Scene research have lead to the devel-opment of systems which automatically extract key concepts from the text of a fiction book and generate computer animated movies depicting the sto-ry. Extracting such annotations from raw fiction text is a laborious process and so in this work we evaluate appropriate candidates to serve as the basis for the required annotations for generating interactive virtual worlds. We val-idate our choice by generating adventure games: interactive virtual worlds which create a stylized representation of the environment described in the text, populate it with characters related to the story and define game goals related to the plot of the fiction story. Our prototype produces a fully playa-ble game, making use of an existing open-source game engine. The pro-cess is evaluated using user tests in which participants are asked to meas-ure the accuracy with which the game represents the events, characters and goals described in the story. The response indicates that the chosen an-notation set is sufficient to define a game that is a plausibly acceptable rep-resentation of the text.
- Full Text:
- Date Issued: 2010
Minimum spanning trees for valley and ridge characterization in digital elevation maps
- Bangay, Shaun D, de Bruyn, David, Glass, Kevin R
- Authors: Bangay, Shaun D , de Bruyn, David , Glass, Kevin R
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433247 , vital:72955 , https://doi.org/10.1145/1811158.1811171
- Description: Texture synthesis employs neighbourhood matching to generate appropriate new content. Terrain synthesis has the added constraint that new content must be geographically plausible. The profile recognition and polygon breaking algorithm (PPA) [Chang et al. 1998] provides a robust mechanism for characterizing terrain as systems of valley and ridge lines in digital elevation maps. We exploit this to create a terrain characterization metric that is robust, efficient to compute and is sensitive to terrain properties.
- Full Text:
- Date Issued: 2010
- Authors: Bangay, Shaun D , de Bruyn, David , Glass, Kevin R
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433247 , vital:72955 , https://doi.org/10.1145/1811158.1811171
- Description: Texture synthesis employs neighbourhood matching to generate appropriate new content. Terrain synthesis has the added constraint that new content must be geographically plausible. The profile recognition and polygon breaking algorithm (PPA) [Chang et al. 1998] provides a robust mechanism for characterizing terrain as systems of valley and ridge lines in digital elevation maps. We exploit this to create a terrain characterization metric that is robust, efficient to compute and is sensitive to terrain properties.
- Full Text:
- Date Issued: 2010
Parallel packet classification using GPU co-processors
- Nottingham, Alistair, Irwin, Barry V W
- Authors: Nottingham, Alistair , Irwin, Barry V W
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430250 , vital:72677 , https://doi.org/10.1145/1899503.1899529
- Description: In the domain of network security, packet filtering for classification pur-poses is of significant interest. Packet classification provides a mecha-nism for understanding the composition of packet streams arriving at distinct network interfaces, and is useful in diagnosing threats and un-covering vulnerabilities so as to maximise data integrity and system se-curity. Traditional packet classifiers, such as PCAP, have utilised Con-trol Flow Graphs (CFGs) in representing filter sets, due to both their amenability to optimisation, and their inherent structural applicability to the metaphor of decision-based classification. Unfortunately, CFGs do not map well to cooperative processing implementations, and single-threaded CPU-based implementations have proven too slow for real-time classification against multiple arbitrary filters on next generation networks. In this paper, we consider a novel multithreaded classification algorithm, optimised for execution on GPU co-processors, intended to accelerate classification throughput and maximise processing efficien-cy in a highly parallel execution context.
- Full Text:
- Date Issued: 2010
- Authors: Nottingham, Alistair , Irwin, Barry V W
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430250 , vital:72677 , https://doi.org/10.1145/1899503.1899529
- Description: In the domain of network security, packet filtering for classification pur-poses is of significant interest. Packet classification provides a mecha-nism for understanding the composition of packet streams arriving at distinct network interfaces, and is useful in diagnosing threats and un-covering vulnerabilities so as to maximise data integrity and system se-curity. Traditional packet classifiers, such as PCAP, have utilised Con-trol Flow Graphs (CFGs) in representing filter sets, due to both their amenability to optimisation, and their inherent structural applicability to the metaphor of decision-based classification. Unfortunately, CFGs do not map well to cooperative processing implementations, and single-threaded CPU-based implementations have proven too slow for real-time classification against multiple arbitrary filters on next generation networks. In this paper, we consider a novel multithreaded classification algorithm, optimised for execution on GPU co-processors, intended to accelerate classification throughput and maximise processing efficien-cy in a highly parallel execution context.
- Full Text:
- Date Issued: 2010
Vice-Chancellor's welcoming address 2010
- Authors: Badat, Saleem
- Date: 2010
- Language: English
- Type: text
- Identifier: vital:7590 , http://hdl.handle.net/10962/d1006581
- Description: From introduction: Rhodes University, which means, you and I and academics and support staff, exists to serve three purposes. The first is to produce knowledge, so that we can advance understanding of our natural and social worlds and enrich our accumulated scientific and cultural heritage. As a university our second purpose is to disseminate knowledge and to cultivate minds. Our goal is to ensure that you can think imaginatively, “effectively and critically”; that you “achieve depth in some field of knowledge”; that you can critique and construct alternatives, that you can communicate cogently, orally and in writing, and that you have a “critical appreciation of the ways in which we gain knowledge and understanding of the universe, of society, and of ourselves” Our final purpose as a university is to undertake community engagement. On the one hand this involves your voluntary participation in community projects undertaken thorough our Community Engagement office. On the other hand, it involves service-learning, in which through your academic courses you take part “in activities where both the community” and you benefit, “and where the goals are to provide a service to the community and, equally, to enhance (your) learning through rendering this service”
- Full Text:
- Date Issued: 2010
- Authors: Badat, Saleem
- Date: 2010
- Language: English
- Type: text
- Identifier: vital:7590 , http://hdl.handle.net/10962/d1006581
- Description: From introduction: Rhodes University, which means, you and I and academics and support staff, exists to serve three purposes. The first is to produce knowledge, so that we can advance understanding of our natural and social worlds and enrich our accumulated scientific and cultural heritage. As a university our second purpose is to disseminate knowledge and to cultivate minds. Our goal is to ensure that you can think imaginatively, “effectively and critically”; that you “achieve depth in some field of knowledge”; that you can critique and construct alternatives, that you can communicate cogently, orally and in writing, and that you have a “critical appreciation of the ways in which we gain knowledge and understanding of the universe, of society, and of ourselves” Our final purpose as a university is to undertake community engagement. On the one hand this involves your voluntary participation in community projects undertaken thorough our Community Engagement office. On the other hand, it involves service-learning, in which through your academic courses you take part “in activities where both the community” and you benefit, “and where the goals are to provide a service to the community and, equally, to enhance (your) learning through rendering this service”
- Full Text:
- Date Issued: 2010
Visual technology for the autonomous learning of mathematics:
- Linneweber-Lammerskitten, Helmut, Schäfer, Marc, Samson, Duncan
- Authors: Linneweber-Lammerskitten, Helmut , Schäfer, Marc , Samson, Duncan
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140949 , vital:37931 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20930
- Description: This paper describes a collaborative research and development project between the University of Applied Sciences Northwestern Switzerland and Rhodes University in South Africa. The project seeks to establish, disseminate and research the efficacy and use of short video clips designed specifically for the autonomous learning of mathematics. Specific to the South African context is our interest in capitalising on the ubiquity of cellphone technology and the autonomous affordances offered by mobile learning. This paper engages with a number of theoretical and pedagogical issues relating to the design, production and use of these video clips. Although the focus is specific to the contexts of South Africa and Switzerland, the discussion is of broad applicability.
- Full Text:
- Date Issued: 2010
- Authors: Linneweber-Lammerskitten, Helmut , Schäfer, Marc , Samson, Duncan
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140949 , vital:37931 , https://0-hdl.handle.net.wam.seals.ac.za/10520/EJC20930
- Description: This paper describes a collaborative research and development project between the University of Applied Sciences Northwestern Switzerland and Rhodes University in South Africa. The project seeks to establish, disseminate and research the efficacy and use of short video clips designed specifically for the autonomous learning of mathematics. Specific to the South African context is our interest in capitalising on the ubiquity of cellphone technology and the autonomous affordances offered by mobile learning. This paper engages with a number of theoretical and pedagogical issues relating to the design, production and use of these video clips. Although the focus is specific to the contexts of South Africa and Switzerland, the discussion is of broad applicability.
- Full Text:
- Date Issued: 2010
A Framework for the Rapid Development of Anomaly Detection Algorithms in Network Intrusion Detection Systems
- Barnett, Richard J, Irwin, Barry V W
- Authors: Barnett, Richard J , Irwin, Barry V W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428644 , vital:72526 , https://www.researchgate.net/profile/Johan-Van-Niekerk-2/publication/220803295_E-mail_Security_awareness_at_Nelson_Mandela_Metropolitan_University_Registrar's_Division/links/0deec51909304b0ed8000000/E-mail-Security-awareness-at-Nelson-Mandela-Metropolitan-University-Registrars-Division.pdf#page=289
- Description: Most current Network Intrusion Detection Systems (NIDS) perform de-tection by matching traffic to a set of known signatures. These systems have well defined mechanisms for the rapid creation and deployment of new signatures. However, despite their support for anomaly detection, this is usually limited and often requires a full recompilation of the sys-tem to deploy new algorithms.
- Full Text:
- Date Issued: 2009
- Authors: Barnett, Richard J , Irwin, Barry V W
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428644 , vital:72526 , https://www.researchgate.net/profile/Johan-Van-Niekerk-2/publication/220803295_E-mail_Security_awareness_at_Nelson_Mandela_Metropolitan_University_Registrar's_Division/links/0deec51909304b0ed8000000/E-mail-Security-awareness-at-Nelson-Mandela-Metropolitan-University-Registrars-Division.pdf#page=289
- Description: Most current Network Intrusion Detection Systems (NIDS) perform de-tection by matching traffic to a set of known signatures. These systems have well defined mechanisms for the rapid creation and deployment of new signatures. However, despite their support for anomaly detection, this is usually limited and often requires a full recompilation of the sys-tem to deploy new algorithms.
- Full Text:
- Date Issued: 2009
An Integrated Connection Management and Control Protocol for Audio Networks
- Foss, Richard, Gurdan, Robby, Klinkradt, Bradley, Chigwamba, Nyasha
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427111 , vital:72415 , https://www.aes.org/e-lib/browse.cfm?elib=15135
- Description: With the advent of digital networks that link audio devices, there is a need for a protocol that integrates control and connection management, allows for streaming of all media content such as audio and video between devices from different manufacturers, and that provides a common approach to the control of these devices. This paper proposes such a protocol, named XFN, currently being standardized as part of the AES X170 project. XFN is an IP-based peer to peer network protocol, in which any device on the network may send or receive connection management, control, and monitoring messages. Essential to the XFN protocol is the fact that each parameter in a device can be addressed via a hierarchical structure that reflects the natural layout of the device.
- Full Text:
- Date Issued: 2009
- Authors: Foss, Richard , Gurdan, Robby , Klinkradt, Bradley , Chigwamba, Nyasha
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427111 , vital:72415 , https://www.aes.org/e-lib/browse.cfm?elib=15135
- Description: With the advent of digital networks that link audio devices, there is a need for a protocol that integrates control and connection management, allows for streaming of all media content such as audio and video between devices from different manufacturers, and that provides a common approach to the control of these devices. This paper proposes such a protocol, named XFN, currently being standardized as part of the AES X170 project. XFN is an IP-based peer to peer network protocol, in which any device on the network may send or receive connection management, control, and monitoring messages. Essential to the XFN protocol is the fact that each parameter in a device can be addressed via a hierarchical structure that reflects the natural layout of the device.
- Full Text:
- Date Issued: 2009