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A comparison of three techniques for fluorochrome marking of juvenile Clarias gariepinus otoliths

- Wartenberg, Reece, Booth, Anthony J, Weyl, Olaf L F

Authors: Wartenberg, Reece , Booth, Anthony J , Weyl, Olaf L F
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/446742 , vital:74557 , https://doi.org/10.1080/15627020.2011.11407480
Description: Intramuscular injection of the antibiotic oxytetracycline (OTC) has been the only method previously employed for chemically marking C. gariepinus otoliths for ageing studies. This study compared intramuscular injection, immersion, and dietary incorporation methods of administering OTC to determine the most effective technique. No differences in either growth or mortality were found between experimental groups while intramuscular injection of OTC was found to be superior to either mass immersion or dietary inclusion of OTC when marking Clarias gariepinus otoliths.
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Date Issued: 2011

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An evaluation of lightweight classification methods for identifying malicious URLs

- Egan, Shaun P, Irwin, Barry V W

Authors: Egan, Shaun P , Irwin, Barry V W
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/429839 , vital:72644 , 10.1109/ISSA.2011.6027532
Description: Recent research has shown that it is possible to identify malicious URLs through lexical analysis of their URL structures alone. This paper intends to explore the effectiveness of these lightweight classification algorithms when working with large real world datasets including lists of malicious URLs obtained from Phishtank as well as largely filtered be-nign URLs obtained from proxy traffic logs. Lightweight algorithms are defined as methods by which URLs are analysed that do not use exter-nal sources of information such as WHOIS lookups, blacklist lookups and content analysis. These parameters include URL length, number of delimiters as well as the number of traversals through the directory structure and are used throughout much of the research in the para-digm of lightweight classification. Methods which include external sources of information are often called fully featured classifications and have been shown to be only slightly more effective than a purely lexical analysis when considering both false-positives and false-negatives. This distinction allows these algorithms to be run client side without the introduction of additional latency, but still providing a high level of accu-racy through the use of modern techniques in training classifiers. Anal-ysis of this type will also be useful in an incident response analysis where large numbers of URLs need to be filtered for potentially mali-cious URLs as an initial step in information gathering as well as end us-er implementations such as browser extensions which could help pro-tect the user from following potentially malicious links. Both AROW and CW classifier update methods will be used as prototype implementa-tions and their effectiveness will be compared to fully featured analysis results. These methods are interesting because they are able to train on any labelled data, including instances in which their prediction is cor-rect, allowing them to build a confidence in specific lexical features. This makes it possible for them to be trained using noisy input data, making them ideal for real world applications such as link filtering and information gathering.
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Date Issued: 2011

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Development of an ICT road map for eservices in rural areas

- Jere, Norbert R, Thinyane, Mamello, Terzoli, Alfredo

Authors: Jere, Norbert R , Thinyane, Mamello , Terzoli, Alfredo
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/430695 , vital:72709 , https://ieeexplore.ieee.org/abstract/document/6144217
Description: ICTs, driven by the convergence of computers, telecommunications and traditional media, are crucial for the knowledge-based economy of the future. The rapid technological changes have resulted in different ideas being suggested for the expected ICT applications. As a result, different e-Service applications have being developed as a way to fos-ter ICT developments. However, ICT applications deployed at the mo-ment may not be able to sustain the rural communities in maybe 10 years or more to come. The paper considers the past, analyzes the present and conduct surveys to gain insight into the future. Based on all of this information, the research tries to provide an ICT road map for what is to come. What kind of applications can we develop now to cater for the technological changes, so that the ICT applications developed today would still be compatible with those developed in years to come? The Siyakhula Living Lab (SLL) is used as the case study in this paper and some interviews and literature review are done to get different ide-as on the future of ICTs.
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Date Issued: 2011

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Invasive alien freshwater fishes in the Wilderness Lakes System, a wetland of international importance in the Western Cape Province, South Africa

- Olds, Alexis A, Smith, M K S, Weyl, Olaf L F, Russell, I A

Authors: Olds, Alexis A , Smith, M K S , Weyl, Olaf L F , Russell, I A
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/446879 , vital:74567 , https://doi.org/10.1080/15627020.2011.11407491
Description: The Wilderness Lakes System incorporates a RAMSAR listed wetland. Previous ichthyological surveys reported three invasive freshwater fishes; Oreochromis mossambicus (Mozambique tilapia), Gambusia affinis (mosquitofish) and Micropterus salmoides (largemouth bass) from this system. To assess the status of these alien fishes, the fish assemblages in the lakes system were sampled with seine nets and fyke nets in 2009 and 2010. A total of 87 893 fish comprising 16 species were caught. In addition to confirming the persistence of O. mossambicus and G. affinis in the system, the current study also reports the presence of a new invader, Cyprinus carpio (common carp). M. salmoides were absent from 2009 and 2010 samples.
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Date Issued: 2011

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Publicising chemistry in a multicultural society through chemistry outreach

- Harrison, T G, Shallcross, D E, Norman, N C, Sewry, Joyce D, Davies-Coleman, Michael T

Authors: Harrison, T G , Shallcross, D E , Norman, N C , Sewry, Joyce D , Davies-Coleman, Michael T
Date: 2011
Language: English
Type: Article
Identifier: vital:6573 , http://hdl.handle.net/10962/d1004136
Description: Given the emphasis in Higher Education on community engagement in South Africa and the importance of international collaboration, we discuss a joint approach to chemistry outreach in two countries on two continents with widely differing target school audiences. We describe the history of the partnership between the chemistry departments at Rhodes University and the University of Bristol and provide an outline of the chemistry content of their outreach initiatives, the modes of delivery, the advantages to both departments and their students for involvement in various levels of outreach, the challenges they still face and additional opportunities that such work facilitated. The lecture demonstration 'A Pollutant's Tale' was presented to thousands of learners all over the world, including learners at resource-deprived schools in South Africa. Challenges to extend outreach activities in South Africa include long travelling distances, as well as a lack of facilities (such as school halls and electricity) at schools. Outreach activities not only impacted on the target audience of young learners, they also impacted upon the postgraduate and other chemistry students taking part in these initiatives. This collaboration strengthened both institutions and their outreach work and may also lead to chemistry research collaborations between the academics involved.
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Date Issued: 2011

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SOA driven architectures for service creation through enablers in an IMS testbed

- Tsietsi, Mosiuoa, Terzoli, Alfredo, Wells,George C

Authors: Tsietsi, Mosiuoa , Terzoli, Alfredo , Wells,George C
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/430726 , vital:72711 , https://ieeexplore.ieee.org/abstract/document/6144230
Description: Standards development organisations have long been in agreement that the most appropriate and cost effective way of developing services for the IP Multimedia Subsystem (IMS) is through the use - and re-use - of service capabilities, which are the building blocks for developing complex services. IMS specifications provide a theoretical framework for how service capabilities can be aggregated into large service appli-cations. However, there is little evidence that mainstream IMS service development is capability-based, and many services are still designed in a monolithic way, with no re-use of existing functionality. Telecom-munication networks are well positioned to stimulate the Internet ser-vices market by exposing these service enablers to third parties. In this paper, we marry the two issues by defining an extended IMS service layer (EISL) that provides a service broker that is the central agent in both service interaction management and the execution of external re-quests from third parties. A prototypical implementation of the service broker is described that was developed using a converged SIP servlet container, and a discussion is also provided that details how third party developers could use HTTP APIs to interact with a service broker in or-der to gain access to network capabilities.
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Date Issued: 2011

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Stable isotope methods: the effect of gut contents on isotopic ratios of zooplankton

- Hill, Jaclyn M, McQuaid, Christopher D

Authors: Hill, Jaclyn M , McQuaid, Christopher D
Date: 2011
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/444623 , vital:74255 , https://doi.org/10.1016/j.ecss.2011.02.002
Description: In the past decade there has been an increased awareness of the potential for methodological bias resulting from multiple pre-analytical procedures in foodweb interpretations based on stable isotope techniques. In the case of small organisms, this includes the effect of gut contents on whole body signatures. Although gut contents may not reflect actual assimilation, their carbon and nitrogen values will be isotopically lighter than after the same material has been assimilated. The potential skewing of isotopic ratios in whole organism samples is especially important for aquatic environments as many studies involve trophic relationships among small zooplankton. This is particularly important in pelagic waters, where herbivorous zooplankton comprise small taxa. Hence this study investigated the effect of gut contents on the δ13C and δ15N ratios of three size classes of zooplankton (1.0–2.0, 2.0–4.0 and >4.0mm) collected using bongo net tows in the tropical waters of the south-west Indian Ocean. Animals were collected at night, when they were likely to be feeding, sieved into size classes and separated into genera. We focused on Euphausia spp which dominated zooplankton biomass. Three treatment types were processed: bulk animals, bulk animals without guts and tail muscle from each size class at 10 bongo stations.
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Date Issued: 2011

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