Network neutral control over quality of service networks
- 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
Selective removal of chromium (VI) from sulphates and other metal anions using an ion-imprinted polymer
- Authors: Pakade, V , Cukrowska, E , Darkwa, J , Torto, N , Chimuka, L
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6588 , http://hdl.handle.net/10962/d1004171
- Description: A linear copolymer was prepared from 4-vinylpyridine and styrene. An ion-imprinted polymer (IIP) specific for Cr (VI) adsorption was prepared by copolymerisation of the quaternised linear copolymer (quaternised with 1,4-chlorobutane), 2-vinylpyridine functional monomer and ethylene glycol dimethacrylate (EGDMA), as the cross-linking monomer, in the presence of 1,1’-azobis(cyclohexanecarbonitrile) as initiator. Ammonium dichromate and aqueous methanol were used as a template and porogenic solvent, respectively. Leaching of the chromate template from the polymer particles was achieved with successive stirring of the ion-imprinted polymer (IIP) particles in 4 M HNO3 solutions to obtain leached materials, which were then used for selective rebinding of Cr (VI) ions from aqueous solutions. Similarly, the non-imprinted polymer/ control polymer (NIP/CP) material was also prepared under exactly the same conditions as the IIP but without the chromate anion template. Various parameters, such as solution pH, initial concentration, aqueous phase volume, sorbent dosage, contact time and leaching solution volumes, were investigated. Scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, BET surface area and pore size analysis were used for the characterisation of IIP (both unleached and leached) and CP materials. Optimal parameters were as follows: solution pH, 3; contact time, 120 min; eluent, 20 mℓ of 0.1 M NaOH; and sorbent amount, 125 mg. Maximum retention capacity of IIP and CP was 37.58 and 25.44 mg∙g-1, respectively. The extraction efficiencies of the IIP and CP were compared using a batch and SPE mode of extraction. In the absence of high concentrations of ions, especially sulphate ions, both CP and IIP demonstrated no differences in binding of Cr (VI), which was almost 100%. However, in the presence of high concentrations of sulphate ions, the selectivity on the CP completely collapsed. The study clearly demonstrates the suitably of the developed IIP for selective extraction of Cr (VI) in complex samples such as those from acid mine drainage. The selectivity was also compared by direct injection of the real-world sample, both spiked and non-spiked, into that obtained after IIP selective extraction. Despite the method’s very low detection limits for direct injection (below 1 μg∙ℓ-1), no Cr (VI) was obtained. However, after IIP selective extraction, spiked Cr (VI) was detected in the spiked sample.
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- Date Issued: 2011
The PINIT domain of PIAS3: structure-function analysis of its interaction with STAT3
- 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.
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- Date Issued: 2011
The xfn connection management and control protocol
- 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.
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- Date Issued: 2011
Towards a standard model for networked audio devices
- 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.
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- Date Issued: 2011
When breast is not best: young women and breast reduction surgery
- 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.
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- Date Issued: 2011
Business Management: BEC 121 & 121E
- Authors: Masocha, Reginald , Rungani, Ellen , Puchert, Juliet
- Date: 2011-01
- Subjects: Management
- Language: English
- Type: Examination paper
- Identifier: vital:17515 , http://hdl.handle.net/10353/d1011118
- Description: Business Management: BEC 121 & 121E, Supplementary examination January/February 2011.
- Full Text: false
- Date Issued: 2011-01
English: ECL 320
- Authors: Formson, C , Nyika, N , Morkel, N , Blatchford, M , Scott, R , Makwela, N , Wood, F
- Date: 2011-01
- Language: English
- Type: Examination paper
- Identifier: vital:18289 , http://hdl.handle.net/10353/d1011295
- Description: English: ECL 320, Supplementary examination January 2011.
- Full Text: false
- Date Issued: 2011-01
Business Mathematics: AMB 111
- Date: 2010-06
- Subjects: Business mathematics
- Language: English
- Type: Examination paper
- Identifier: vital:17471 , http://hdl.handle.net/10353/d1010286
- Description: Business Mathematics: AMB 111, June examination 1st semester 2010.
- Full Text: false
- Date Issued: 2010-06
Interpreting the Text of the Hebrew Bible: THB 211
- Authors: Adolph, E , Oosthuizen, R
- Date: 2010-06
- Language: English
- Type: Examination paper
- Identifier: vital:18152 , http://hdl.handle.net/10353/d1011074
- Description: Interpreting the Text of the Hebrew Bible: THB 211, degree examination June 2010.
- Full Text: false
- Date Issued: 2010-06
Taxation 3: ATA 311E/ ATV 311E
- Authors: Hirschbeck, L , Stevens, N , Olivier, J
- Date: 2010-06
- Subjects: Accounting
- Language: English
- Type: Examination paper
- Identifier: vital:17404 , http://hdl.handle.net/10353/d1009765
- Description: Taxation 3: ATA 311E / ATV 311E, June 2010 Final Examination.
- Full Text:
- Date Issued: 2010-06
Indexes and Abstracts: INF 212
- Authors: Chisamatanga, N , Ondari-Okemwa, E M
- Date: 2010-04
- Language: English
- Type: Examination paper
- Identifier: vital:17989 , http://hdl.handle.net/10353/d1010563
- Description: Indexes and Abstracts: INF 212, special supplementary examination April 2010.
- Full Text: false
- Date Issued: 2010-04
A histological description of ovarian recrudescence in two Labeo victorianus populations
- 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.
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- Date Issued: 2010
A Proxy Approach for Interoperability and Common Control of Networked Digital Audio Devices
- 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
Developing an ionospheric map for South Africa
- Authors: McKinnell, Lee-Anne , Okoh, D I , Cilliers, P J
- Date: 2010
- Language: English
- Type: Article
- Identifier: vital:6822 , http://hdl.handle.net/10962/d1004438 , http://dx.doi.org/10.5194/angeo-28-1431-2010
- Description: The development of a map of the ionosphere over South Africa is presented in this paper. The International Reference Ionosphere (IRI) model, South African Bottomside Ionospheric Model (SABIM), and measurements from ionosondes in the South African Ionosonde Network, were combined within their own limitations to develop an accurate representation of the South African ionosphere. The map is essentially in the form of a computer program that shows spatial and temporal representations of the South African ionosphere for a given set of geophysical parameters. A validation of the map is attempted using a comparison of Total Electron Content (TEC) values derived from the map, from the IRI model, and from Global Positioning System (GPS) measurements. It is foreseen that the final South African ionospheric map will be implemented as a Space Weather product of the African Space Weather Regional Warning Centre.
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- Date Issued: 2010
Does reservoir trophic status influence the feeding and growth of the sharptooth catfish, Clarias gariepinus (Teleostei: Clariidae)?
- 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.
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- Date Issued: 2010
Factors affecting recapture rates of raggedtooth sharks Carcharias taurus tagged off the east coast of South Africa
- 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.
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- Date Issued: 2010
Growth, reproduction and population structure of Diplotaxodon limnothrissa in the southeast arm of Lake Malawi
- 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).
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- Date Issued: 2010
Identifying annotations for adventure game generation from fiction text
- 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.
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- Date Issued: 2010
Minimum spanning trees for valley and ridge characterization in digital elevation maps
- 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