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Stable isotope ratios indicate differential omnivory among syntopic rocky shore suspension-feeders

- Richoux, Nicole B, Vermeulen, Ilke, Froneman, P William

Authors: Richoux, Nicole B , Vermeulen, Ilke , Froneman, P William
Date: 2014
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/68261 , vital:29224 , https://doi.org/10.1007/s00227-013-2358-6
Description: Publisher version , We utilised stable isotope ratios to assess differences in diet among three indigenous and syntopic rocky shore suspension-feeders (mussels Perna perna, barnacles Tetraclita serrata, and polychaetes Gunnarea gaimardi). We also determined the spatial and temporal variability in the suspension-feeder diets by collecting specimens on two occasions from two regions adjacent to hydrologically distinct river mouths (i.e. one with larger annual freshwater throughput than the other). The results showed that the isotopic niches (used as proxies for trophic niches) of the three species did not overlap and that the barnacles occupied a trophic position (3.4) well above those of the mussels (2) and polychaetes (2.6). We ascribed the interspecific differences primarily to the disparate feeding mechanisms used by the species. Large-scale regional (~50 km) differences in suspension-feeder diets were apparent, but not small-scale (up to a few km north and south of each estuary mouth). The regional differences in diet resulted from the increased availability of estuarine-origin suspended particulate matter (SPM) and zooplankton in the region adjacent to the river with relatively larger freshwater output, although overall incorporation of zooplankton versus mixed SPM into consumer diets was relatively consistent between regions and through time. Temporal shifts in suspension-feeder diets were apparent from stable carbon isotope ratios in the consumers. Our results showcase the measurable effects of regional-scale processes that can alter the food sources for dominant primary consumers in the rocky intertidal, thus potentially affecting entire food webs through bottom-up processes. The clear evidence for trophic niche partitioning offers valuable insights into how potentially strong competitors can coexist.
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Date Issued: 2014

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Starways Arts: a built environment expressing holistic lifestyles dedicated to visual and performing arts in Hogsback, Eastern Cape, South Africa

- Steele, John

Authors: Steele, John
Date: 2014
Language: English
Type: text , Article
Identifier: http://hdl.handle.net/11260/990 , vital:30179
Description: In 1992, Anton van der Merwe and his life partner Gwyneth Lloyd moved from Randjesfontein Pottery in Midrand, between Johannesburg and Pretoria, to an undeveloped smallholding in the densely forested rural village of Hogsback. The past 22 years have seen an ongoing process of settling down and construction of necessary buildings. This paper seeks to explore aspects of philosophical and architectural influences that served as some of the foundation stones for creation of an eclectic series of buildings, including their home, visual arts studios, a gallery, a community theatre and guest accommodation. A review of these buildings will show that Van der Merwe and Lloyd have developed an idiosyncratic construction style that incorporates alternative technology with empathetic use of natural resources, which results in organically flowing living and working spaces that are fit for purpose, have substantial presence and have minimal environmental impact.
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Date Issued: 2014

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Structural change, productivity and the middle income trap: South Africa in comparative perspective

- Fryer, David, Cattaneo, Nicolette S

Authors: Fryer, David , Cattaneo, Nicolette S
Date: 2014
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/470354 , vital:77351 , ISBN
Description: Most BRICS countries have been characterized as either being in the middle income trap (South Africa, and in most studies, Brazil) or vulnerable to it. While China and India are unlikely to stagnate to the extent of being caught in such a trap, there is concern about the impact on the global economy if their growth rates decelerate significantly. T his paper explores patterns of structural change and productivity growth in the BRICS countries with a focus on South Africa and the concept of a middle income trap. The paper is structured as follows. Section 1 considers definitions and which countries are affected. Section 2 considers competing explanations of patterns of structural change and productivity growth. Section 3 focuses on the productivity debate in South Africa from a comparative perspective. Section 4 concludes with policy implications and directions for future research in the BRICS countries.
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Date Issued: 2014

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A qualitative ecological risk assessment of the invasive Nile tilapia, Oreochromis niloticus in a sub-tropical African river system (Limpopo River, South Africa)

- Zengeya, Tsungai A, Robertson, Mark P, Booth, Anthony J, Chimimba, Christian T

Authors: Zengeya, Tsungai A , Robertson, Mark P , Booth, Anthony J , Chimimba, Christian T
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/123575 , vital:35457 , https://doi.10.1002/aqc.2258
Description: 1. This study outlines the development of a qualitative risk assessment method and its application as a screening tool for determining the risk of establishment and spread of the invasive Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), within the central sub-catchment of the Limpopo River basin in northern South Africa. 2. The assessment used known physiological tolerance limits of O. niloticus in relation to minimum water temperature, presence or absence of dams, seasonality of river flows, and the presence of indigenous fish species of concern to identify river systems that would be suitable for O. niloticus establishment. 3. River sections along the Limpopo main river channel and the immediate reaches of its associated tributaries east of the Limpopo/Lephalala river confluence along the Botswana–South Africa–Zimbabwe border were identified as being highly vulnerable to O. niloticus invasion. Rivers in the upper Bushveld catchment (Upper Limpopo, Mogalakwena, Lephalala, Mokolo, Matlabas and Crocodile rivers) were categorized as of medium ecological risk, while headwater streams were considered to be of low ecological risk. The decrease in vulnerability between lowveld and highveld river sections was mainly a function of low water temperatures (8–12˚C) associated with increasing altitude. 4. Oreochromis niloticus is already established in the lower catchment of the Limpopo River basin where indigenous congenerics are at an extinction risk through hybridization and competition exclusion. Oreochromis niloticus, therefore, poses an ecologically unacceptable risk to river systems in the upper catchment where it is yet to establish. The current risk assessment model provides a useful preliminary framework for the identification of river systems that are vulnerable to an O. niloticus invasion where conservation measures should be directed and implemented to prevent its introduction and spread within the Limpopo river system.
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Date Issued: 2013

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Composite polyester membranes with embedded dendrimer hosts and bimetallic Fe/Ni nanoparticles: synthesis, characterisation and application to water treatment

- Malinga, S P, Arotiba, O A, Mapolie, S F, Krause, Rui W M, Mamba, Bhekie B, Diallo, M S

Authors: Malinga, S P , Arotiba, O A , Mapolie, S F , Krause, Rui W M , Mamba, Bhekie B , Diallo, M S
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/125086 , vital:35727 , https://doi.org/10.1007/s11051-013-1698-y
Description: This study describes the preparation, characterization and evaluation of new composite membranes with embedded dendrimer hosts and Fe/Ni nanoparticles. These new reactive membranes consist of films of cyclodextrin–poly(propyleneimine) dendrimers (β-CD–PPI) that are deposited onto commercial polysulfone microporous supports and crosslinked with trimesoyl chloride (TMC). The membranes were subsequently loaded with Fe/Ni nanoparticles and evaluated as separation/reactive media in aqueous solutions using 2,4,6-trichlorophenol as model pollutant. The morphology and physicochemical properties of the composite membranes were characterised using high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy and measurements of contact angle, water intake, porosity and water permeability. The sorption capacity and catalytic activity of the membranes were evaluated using ion chromatography, atmospheric pressure chemical ionisation-mass spectrometry and UV–Vis spectroscopy (UV–Vis). The sizes of the embedded Fe/Ni nanoparticles in the membranes ranged from 40 to 66 nm as confirmed by HR-TEM. The reaction rates for the dechlorination of 2,4,6-trichlorophenol ranged from 0.00148 to 0.00250 min−1. In all cases, we found that the reaction by-products consisted of chloride ions and mixtures of compounds including phenol (m/z = 93), 2,4-dichlorophenol (m/z = 163) and 4-chlorophenol (m/z = 128). The overall results of this study suggest that β-CD–PPI dendrimers are promising building blocks for the synthesis of composite and reactive membranes for the efficient removal of chlorinated organic pollutants from water.
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Date Issued: 2013

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Dancing with the devil: formative peer assessment and academic performance

- Mostert, Markus, Snowball, Jeanette D

Authors: Mostert, Markus , Snowball, Jeanette D
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/69301 , vital:29483 , https://doi.org/10.1080/07294360.2012.705262
Description: Peer assessment can be important in developing active and independent learners, as well as providing more and faster feedback in large classes, compared to marking done by tutors. In addition, the evaluative, critical stance required by students in order to assess their peers' work encourages the development of higher-order cognitive skills. Changing roles from being assessed to being an assessor can also improve students' ability to judge and improve on their own work. However, peer assessment does have potential problems and there is some debate as to the appropriate academic level at which to implement it, the kinds of feedback that are given and the ways in which students respond. In addition, there is little evidence that peer assessment has an impact on academic performance. This research reports the results of an online peer assessment exercise for a macroeconomics essay conducted in a large Economics 1 class at Rhodes University. Of the 800 students, about half participated in the peer assessment exercise. Data were collected from students via a formal course evaluation. In addition, a sample of 50 essays was evaluated in terms of the relationship between peer marks and final (tutor) marks received and the impact that peer assessment had on the quality of the final essay submitted. An Ordinary Least Squares regression was used to investigate the impact of peer assessment participation on marks. Results showed that peer marks tended to ‘bunch’ in the 60–68% range, indicating the reluctance of peers to give very high or low marks. In general, peers gave more useful feedback on technical aspects, such as presentation and referencing (which were also the categories in which students most often made improvements), than on content. Regression analysis showed that peer assessment participation was not a significant determinant of final essay mark, but that economics ability and English language proficiency were.
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Date Issued: 2013

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From panic disorder to complex traumatic stress disorder : retrospective reflections on the case of Tariq

- Edwards, David J A

Authors: Edwards, David J A
Date: 2013
Language: English
Type: Article
Identifier: vital:6234 , http://hdl.handle.net/10962/d1007784
Description: This is a phenomenological-hermeneutic case study of Tariq who initially presented with panic disorder. It documents how, as therapy proceeded, the underlying meaning of his initial panic deepened as its roots in traumatic memories of childhood emerged. There were four spaced phases of treatment over four years. The first focused on anxiety management; the second was conceptualized within schema-focused therapy, and evoked and worked with childhood memories using inner child guided imagery; in the third and fourth phases insights gained led to an authentic re-engagement with family members in relationships that had been problematic. The panic attacks resolved and there were two dreams representing a reconfiguring of his relationship with his deceased father. The first two phases were the focus of an unpublished case study presented at a conference in 1995. This article incorporates material from that study and looks back at the case both in light of developments in phases two and three and also in light of theoretical developments in our understanding of complex trauma since the initial presentation.
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Date Issued: 2013

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The nature of geometry instruction and observed learning-outcomes opportunities in Nigerian and South African high schools:

- Atebe, Humphrey U, Schäfer, Marc

Authors: Atebe, Humphrey U , Schäfer, Marc
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/140919 , vital:37929 , DOI: 10.1080/10288457.2011.10740712
Description: The purpose of this qualitative case study involving six secondary school teachers was to obtain insight into how geometry is taught in selected Nigerian and South African high schools. It also aimed, by making use of the van Hiele model of geometry instruction, to elucidate what possible learning opportunities observed instructional methods could offer learners in the subject. The sample comprised three mathematics teachers from Nigeria and three mathematics teachers from South Africa, all of whom were selected using purposive sampling techniques. Instructional activities in six geometry classrooms were recorded on videotape. The van Hiele learning phases provided the framework for data analysis. The findings of this study indicate that observed teaching methods in geometry classrooms in the participating schools offer learners scant opportunity to learn geometry.
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Date Issued: 2013

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Think Piece : conceptions of quality and ‘Learning as Connection’: teaching for relevance

- Lotz-Sisitka, Heila

Authors: Lotz-Sisitka, Heila
Date: 2013
Subjects: Teachers -- Quality -- South Africa , Quality assurance -- South Africa , Effective teaching , Relevance , SADC Regional Environmental Education Programme
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/59635 , vital:27633 , https://www.ajol.info/index.php/sajee/article/view/122256
Description: This think piece captures some of the thinking that emerged in and through the Southern African Development Community (SADC) Regional Environmental Education Programme research programme. This research programme emerged over a five-year period (2008–2012) and involved ten southern African teacher education institutions from eight countries (see ‘Acknowledgements’). The research programme sought to understand what contributions environment and sustainability education could make to debates on educational quality and relevance. Issues of educational quality are high on the national agendas of governments in southern Africa, as it is now well known that providing access to schooling is not a sufficient condition for achieving educational quality. Educational quality is intimately linked to the processes of teaching and learning, but the concept of educational quality is not unproblematic in and of itself. It is, as Noel Gough (2005) noted many years ago, an ‘order word’ that shapes the way people think and practise. Our enquiries during this research programme involved a number of case studies (that were reported on in the Southern African Journal of Environmental Education (SAJEE) in 2008, and are again reported on in this edition of the SAJEE), but the programme also involved theoretical engagement with the concept of educational quality and relevance. This think piece helps to make some of this thinking and theoretical deliberation visible. The author of this think piece was also the leader of the regional research programme and was tasked with synthesising the theoretical deliberations that emerged from the research design which were found to be useful for guiding interpretations and deliberation on more detailed case studies undertaken at country level.
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Date Issued: 2013

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Transcribing the Venda tshikona reedpipe dance

- Tracey, Andrew, Gumboreshumba, Laina

Authors: Tracey, Andrew , Gumboreshumba, Laina
Date: 2013
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/59744 , vital:27644 , http://dx.doi.org/10.21504/amj.v9i3.1909
Description: Starting with the end result, the above transcription is the conclusion I came to after sitting with Laina Gumboreshumba for many hours, watching the videos she made during her recent doctoral research on the tshikona reedpipe dance of the Venda of Limpopo Province in the extreme north of South Africa. The transcription shown in Figure 2 is a skeleton version of the full pipe sound that contains all the information needed to grasp the structure of the sound and teach it or play it. There are always seven different pipes. A full tshikona group has far more than the seven pipes (nanga) shown, because all seven pipe numbers are doubled in every octave present in a group, so there may be up to four or more Pipe 1s, Pipe 2s, etc, of different sizes. All the Pipe 1s play the same pattern together, all the Pipe 2s etc. There are usually four octaves in all, with an incomplete octave of a few higher pitched pipes at the top (phalana). A popular size for a group according to group leaders (malogwane) is twenty eight pipes, which may include some pitch duplicates. A festive performance can number well over one hundred players. The music is heptatonic as you can see from the transcription, and hear for yourself from CD track 1 accompanying this issue of African Music. A chart showing the tuning is included as Figure 1 1 at the end of this article. This article does not address the pipe names; they are simply numbered Pipes 1 to 7, in the order of entry in Mr Netshivhale’s groups. The pipes are end-blown, closed tubes made of a special bamboo, or increasingly today of electrical or other tubing.
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Date Issued: 2013

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Where angels fear to tread: online peer-assessment in a large first-year class

- Mostert, Markus, Snowball, Jeanette D

Authors: Mostert, Markus , Snowball, Jeanette D
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/68845 , vital:29330 , https://doi.org/10.1080/02602938.2012.683770
Description: Publisher version , In the context of widening participation, large classes and increased diversity, assessment of student learning is becoming increasingly problematic in that providing formative feedback aimed at developing student writing proves to be particularly laborious. Although the potential value of peer assessment has been well documented in the literature, the associated administrative burden, also in relation to managing anonymity and intellectual ownership, makes this option less attractive, particularly in large classes. A potential solution involves the use of information and communication technologies to automate the logistics associated with peer assessment in a time-efficient way. However, uptake of such systems in the higher education community is limited, and research in this area is only beginning. This case study reports on the use of the Moodle Workshop module for formative peer assessment of students’ individual work in a first-year introductory macro-economics class of over 800 students. Data were collected through an end-of-course evaluation survey of students. The study found that using the feature-rich Workshop module not only addressed many of the practical challenges associated with paper-based peer assessments, but also provided a range of additional options for enhancing validity and reliability of peer assessments that would not be possible with paper-based systems.
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Date Issued: 2013

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‘Growing’ social protection in developing countries: lessons from Brazil and South Africa

- Barrientos, Armando, Moller, Valerie, Saboia, Joao, Lloyd-Sherlock, Peter, Mase, Julia

Authors: Barrientos, Armando , Moller, Valerie , Saboia, Joao , Lloyd-Sherlock, Peter , Mase, Julia
Date: 2013
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67195 , vital:29058 , https://doi.org/10.1080/0376835X.2013.756098
Description: publisher version , The rapid expansion of social protection in the South provides a rich diversity of experiences and lessons on how best to reduce poverty and ultimately eradicate it. Knowledge on how best to ‘grow’ social assistance, understood as long-term institutions responsible for reducing and preventing poverty, is at a premium. This article examines the expansion of social assistance in Brazil and South Africa, two of the middle income countries widely perceived to have advanced furthest in ‘growing’ social protection. It examines three aspects: the primacy of politics in explaining the expansion of social protection and assistance, the tensions between path-dependence and innovation in terms of institutions and practices, and the poverty and inequality outcomes of social assistance expansion. The article concludes by drawing the main lessons for other developing countries.
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Date Issued: 2013

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A computer network attack taxonomy and ontology

- Van Heerden, Renier P, Irwin, Barry V W, Burke, Ivan D, Leenen, Louise

Authors: Van Heerden, Renier P , Irwin, Barry V W , Burke, Ivan D , Leenen, Louise
Date: 2012
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/430064 , vital:72663 , DOI: 10.4018/ijcwt.2012070102
Description: Computer network attacks differ in the motivation of the entity behind the attack, the execution and the end result. The diversity of attacks has the consequence that no standard classification ex-ists. The benefit of automated classification of attacks, means that an attack could be mitigated accordingly. The authors extend a previous, initial taxonomy of computer network attacks which forms the basis of a proposed network attack ontology in this pa-per. The objective of this ontology is to automate the classifica-tion of a network attack during its early stages. Most published taxonomies present an attack from either the attacker's or defend-er's point of view. The authors' taxonomy presents both these points of view. The framework for an ontology was developed using a core class, the "Attack Scenario", which can be used to characterize and classify computer network attacks.
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Date Issued: 2012

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Classifying network attack scenarios using an ontology

- Van Heerden, Renier, Irwin, Barry V W, Burke, I D

Authors: Van Heerden, Renier , Irwin, Barry V W , Burke, I D
Date: 2012
Language: English
Type: Conference paper
Identifier: vital:6606 , http://hdl.handle.net/10962/d1009326
Description: This paper presents a methodology using network attack ontology to classify computer-based attacks. Computer network attacks differ in motivation, execution and end result. Because attacks are diverse, no standard classification exists. If an attack could be classified, it could be mitigated accordingly. A taxonomy of computer network attacks forms the basis of the ontology. Most published taxonomies present an attack from either the attacker's or defender's point of view. This taxonomy presents both views. The main taxonomy classes are: Actor, Actor Location, Aggressor, Attack Goal, Attack Mechanism, Attack Scenario, Automation Level, Effects, Motivation, Phase, Scope and Target. The "Actor" class is the entity executing the attack. The "Actor Location" class is the Actor‟s country of origin. The "Aggressor" class is the group instigating an attack. The "Attack Goal" class specifies the attacker‟s goal. The "Attack Mechanism" class defines the attack methodology. The "Automation Level" class indicates the level of human interaction. The "Effects" class describes the consequences of an attack. The "Motivation" class specifies incentives for an attack. The "Scope" class describes the size and utility of the target. The "Target" class is the physical device or entity targeted by an attack. The "Vulnerability" class describes a target vulnerability used by the attacker. The "Phase" class represents an attack model that subdivides an attack into different phases. The ontology was developed using an "Attack Scenario" class, which draws from other classes and can be used to characterize and classify computer network attacks. An "Attack Scenario" consists of phases, has a scope and is attributed to an actor and aggressor which have a goal. The "Attack Scenario" thus represents different classes of attacks. High profile computer network attacks such as Stuxnet and the Estonia attacks can now be been classified through the “Attack Scenario” class.
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Date Issued: 2012

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Cryptic variation in an ecological indicator organism: mitochondrial and nuclear DNA sequence data confirm distinct lineages of Baetis harrisoni Barnard (Ephemeroptera: Baetidae) in southern Africa

- Pereira-da-Conceicoa, L L, Price, Benjamin W, Barber-James, Helen M

Authors: Pereira-da-Conceicoa, L L , Price, Benjamin W , Barber-James, Helen M
Date: 2012
Language: English
Type: text , Article
Identifier: vital:7151 , http://hdl.handle.net/10962/d1011855
Description: Baetis harrisoni Barnard is a mayfly frequently encountered in river studies across Africa, but the external morphological features used for identifying nymphs have been observed to vary subtly between different geographic locations. It has been associated with a wide range of ecological conditions, including pH extremes of pH 2.9–10.0 in polluted waters. We present a molecular study of the genetic variation within B. harrisoni across 21 rivers in its distribution range in southern Africa.
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Date Issued: 2012

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Cryptic variation in an ecological indicator organism: mitochondrial and nuclear DNA sequence data confirm distinct lineages of Baetis harrisoni Barnard (Ephemeroptera: Baetidae) in Southern Africa

- Pereira-da-Conceicoa, Lyndall L, Price, Benjamin W, Barber-James, Helen M, Barker, Nigel P, de Moor, Ferdy C, Villet, Martin H

Authors: Pereira-da-Conceicoa, Lyndall L , Price, Benjamin W , Barber-James, Helen M , Barker, Nigel P , de Moor, Ferdy C , Villet, Martin H
Date: 2012
Language: English
Type: Article
Identifier: vital:6535 , http://hdl.handle.net/10962/d1005976 , https://dx.doi.org/10.1186/1471-2148-12-26
Description: Baetis harrisoni Barnard is a mayfly frequently encountered in river studies across Africa, but the external morphological features used for identifying nymphs have been observed to vary subtly between different geographic locations. It has been associated with a wide range of ecological conditions, including pH extremes of pH 2.9–10.0 in polluted waters. We present a molecular study of the genetic variation within B. harrisoni across 21 rivers in its distribution range in southern Africa.
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Date Issued: 2012

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Five unpublished coins of Alexander the Great and his successors in the Rhodes University Collection

- Snowball, Jeanette D, Snowball, Warren D

Authors: Snowball, Jeanette D , Snowball, Warren D
Date: 2012
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/68489 , vital:29267 , http://dx.doi.org/10.7445/50-0-73
Description: Publisher version , The article briefly discusses the economic and political significance of the Alexander III (“the Great”) type silver tetradrachm and publishes three of his coins currently held by the Rhodes University Classics Museum. Based on stylistic elements, they are classified as from the Amphipolis and Arados mints and were probably minted during his lifetime. Two further tetradrachms from the empires of Alexander’s successors, Ptolemy II and Seleucus IV, are also published.
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Date Issued: 2012

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