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Thermoluminescence of kunzite: a study of kinetic processes and dosimetry characteristics

- Ogundare, F O, Alatishe, M A, Chithambo, Makaiko L, Costin, G

Authors: Ogundare, F O , Alatishe, M A , Chithambo, Makaiko L , Costin, G
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124701 , vital:35650 , https://doi.org/10.1016/j.nimb.2016.02.059
Description: Since the use of natural minerals for dating and dose reconstruction using luminescence techniques is well-established and always of interest, we present thermoluminescence characteristics of kunzite, a gem variety of spodumene. The chemical composition of the sample was determined using an Electron Probe MicroAnalyzer.
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Date Issued: 2016

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Time-resolved luminescence from quartz: an overview of contemporary developments and applications

- Chithambo, Makaiko L, Pagonis, Vasilis, Ankjærgaard, Christina

Authors: Chithambo, Makaiko L , Pagonis, Vasilis , Ankjærgaard, Christina
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124743 , vital:35658 , https://doi.org/10.1016/j.physb.2015.10.014
Description: Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al2O3:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.
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Date Issued: 2016

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Transcription factor motif quality assessment requires systematic comparative analysis [version 2; referees: 2 approved]

- Kibet, Caleb K, Machanick, Philip

Authors: Kibet, Caleb K , Machanick, Philip
Date: 2016
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/61169 , vital:27987 , http://dx.doi.org/10.12688/f1000research.7408.2
Description: Transcription factor (TF) binding site prediction remains a challenge in gene regulatory research due to degeneracy and potential variability in binding sites in the genome. Dozens of algorithms designed to learn binding models (motifs) have generated many motifs available in research papers with a subset making it to databases like JASPAR, UniPROBE and Transfac. The presence of many versions of motifs from the various databases for a single TF and the lack of a standardized assessment technique makes it difficult for biologists to make an appropriate choice of binding model and for algorithm developers to benchmark, test and improve on their models. In this study, we review and evaluate the approaches in use, highlight differences and demonstrate the difficulty of defining a standardized motif assessment approach. We review scoring functions, motif length, test data and the type of performance metrics used in prior studies as some of the factors that influence the outcome of a motif assessment. We show that the scoring functions and statistics used in motif assessment influence ranking of motifs in a TF-specific manner. We also show that TF binding specificity can vary by source of genomic binding data. We also demonstrate that information content of a motif is not in isolation a measure of motif quality but is influenced by TF binding behaviour. We conclude that there is a need for an easy-to-use tool that presents all available evidence for a comparative analysis.
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Date Issued: 2016

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Trophic interactions in an austral temperate ephemeral pond inferred using stable isotope analysis

- Dalu, Tatenda, Weyl, Olaf L F, Froneman, P William, Wasserman, Ryan J

Authors: Dalu, Tatenda , Weyl, Olaf L F , Froneman, P William , Wasserman, Ryan J
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/68022 , vital:29185 , https://doi.org/10.1007/s10750-015-2533-5
Description: Publisher version , Ephemeral ponds are vulnerable aquatic habitats which are difficult to protect given their dynamic nature and sensitivity to degradation during dry periods. Little information is available on these habitats in austral regions, with almost no information on food-web structure and complexity. The study aimed to assess trophic interactions among dominant organisms in an ephemeral pond food web, and investigate the importance of autochthonous and allochthonous carbon, using 13C and 15N isotopes. Results of the investigation suggest that the food web comprised four trophic levels, with the top predators being Notonectids (Notonecta sp.) and diving beetles (Cybister tripunctatus (Olivier)). Intermediary trophic levels comprised zooplankton (daphniids and copepodids), macroinvertebrates (e.g. micronectids and molluscs) and tadpoles. Generalist feeders dominated the higher trophic levels (>3) with specialists comprising the lower trophic levels (≤3). The consumers preferred autochthonous fine particulate organic matter, epiphyton and submerged macrophyte organic matter sources over allochthonous sources. Autochthonous organic matter was transferred to the food web via zooplankton and select macroinvertebrates including Micronecta sp. and Physa sp. The food-web structure within the pond appeared to reflect the secondary stage of trophic structural complexity in the evolution of ephemeral ponds over the course of their hydro-period.
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Date Issued: 2016

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Unpacking Pandora’s box: Understanding and categorising ecosystem disservices for environmental management and human wellbeing

- Shackleton, Charlie M, Ruwanza, Sheunesu, Sinasson Sanni, Gisele, Bennett, S, De Lacy, Peter, Modipa, Rebone D, Mtati, Nosiseko, Sachikonye, Mwazvita T B, Thondhlana, Gladman

Authors: Shackleton, Charlie M , Ruwanza, Sheunesu , Sinasson Sanni, Gisele , Bennett, S , De Lacy, Peter , Modipa, Rebone D , Mtati, Nosiseko , Sachikonye, Mwazvita T B , Thondhlana, Gladman
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/182113 , vital:43801 , xlink:href="https://doi.org/10.1007/s10021-015-9952-z"
Description: Research into the benefits that ecosystems contribute to human wellbeing has multiplied over the last few years following from the seminal contributions of the international Millennium Ecosystem Assessment. In comparison, the fact that some ecosystem goods and services undermine or harm human wellbeing has been seriously overlooked. These negative impacts have become known as ecosystem disservices. The neglect of ecosystem disservices is problematic because investments into the management or reduction of ecosystem disservices may yield better outcomes for human wellbeing, or at a lower investment, than management of ecosystem services. Additionally, management to optimise specific ecosystem services may simultaneously exacerbate associated disservices. We posit that one reason for the neglect of ecosystem disservices from the discourse and policy debates around ecosystems and human wellbeing is because there is no widely accepted definition or typology of ecosystem disservices. Here, we briefly examine current understandings of the term ecosystem disservices and offer a definition and a working typology to help generate debate, policy and management options around ecosystem disservices. We differentiate ecosystem disservices from natural hazards and social hazards, consider some of their inherent properties and then classify them into six categories. A variety of examples are used to illustrate the different types of, and management strategies to, ecosystem disservices.
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Date Issued: 2016

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Vertebrate Biostratigraphy of the Witteberg Group and the Devonian-Carboniferous boundary in South Africa

- Gess, Robert W

Authors: Gess, Robert W
Date: 2016
Language: English
Type: text , boook chapter
Identifier: http://hdl.handle.net/10962/73987 , vital:30248 , https://doi.org/10.1007/978-3-319-40859-0_13
Description: Witteberg Group rocks are Late Devonian to Early Carboniferous in age. Comparison with Laurasian sea-level curves has correlated the earliest Carboniferous Tournasian transgression, with the argillaceous Kweekvlei Formation, overlying the arenaceous Witpoort Formation. The Devonian/Carboniferous boundary is globally characterised by a Mass Extinction which extinguished the entire grade of placoderm fish and radically reduced sarcopterygian and acanthodian diversity, preluding an Early Carboniferous radiation of actinopterygians. Analysis of Cape Supergroup biostratigraphy reveals that a fauna preservationally dominated by placoderms, sharks, and gyracanthid acanthodians may be traced from the Upper Bokkeveld Group through the Wagondrift Formation (Witteberg Group) to the Witpoort Formation, wherein it displays an increased diversity of placoderms, as well as sarcopterygians. Overlying strata contain no placoderms or sarcopterygians, but present are some relict sharks and acanthodians, and an increasing abundance of actinopterygians. This congruence confirms sea-level curve based age estimates of the Witteberg Group and the position of the Devonian/Carboniferous boundary.
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Date Issued: 2016

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Visit the exotic birthplaces of transdisciplinarity

- Burt, Jane C, Cockburn, Jessica J, Fox, Helen E, Copteros, Athina

Authors: Burt, Jane C , Cockburn, Jessica J , Fox, Helen E , Copteros, Athina
Date: 2016
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/68442 , vital:29256 , https://doi.org/10.13140/RG.2.1.1511.7048
Description: Publisher version , Preface: Why a new approach to science? The world we live in is very different to the world of one hundred years ago. The world has never been so populated by humans and never before have the spe-cies ‘human’ influenced and manipulated the natural world in the way in which we do now. Academics are calling it the age of the Anthropocene. In the age of the Anthropocene we face different challenges to what hu- mans faced centuries ago. As we find ourselves in this new age we have had to not only question ‘what we know’ but also ‘how we know’ and whether the ‘how we know’ is the right kind of ‘how’ for the problems that we face today. This has led to a questioning of the way in which we generate knowledge and the way in which this knowledge is used. This critique is not aimed at all knowledge generation it is mostly a frustration that has arisen out of the physical and biological sciences with the realisation that doing good science is just not enough to bring about meaningful change in the world. Trans-disciplinary scientists and practitioners have begun this journey in search of a new kind of science - A science in service of society! This tourist trip will re- trace the few first steps of these emerging ideas so that we can understand where these new ideas have come from and how they may influence our own research. , This document was developed for a postgraduate course on Transdisciplinary research held at Rhodes University. It explores three key theoretical approaches to transdisciplinarity in relation to the question 'Why TD?'.
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Date Issued: 2016

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Walking into Africa in a Chinese way: Hua Jiming’s mindful entry as counterbalance

- Simbao, Ruth K

Authors: Simbao, Ruth K
Date: 2016
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/146167 , vital:38501 , ISBN 9791024005799 , https://books.google.co.za/books?id=VGSwDwAAQBAJanddq=Afrique-Asie:+Arts,+espaces,+pratiquesandsource=gbs_navlinks_s
Description: Book abstract. The links between Africa and Asia are at the very heart of globalization. Understanding its richness and complexity requires a study carried out from various points of view. Particular attention to culture is essential. Centered on the work of visual artists and performers, on town planning, literature and spirituality, the essays gathered here call on many disciplines: art history and history, anthropology, sociology, geography, architecture, comparative literature, visual and culture studies. They constitute a network of crossed views on a subject which no serious reflection on globalization can do today.
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Date Issued: 2016

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Water footprint assessment of citrus production in South Africa: A case study of the Lower Sundays River Valley

- Munro, Samantha A, Fraser, Gavin C G, Snowball, Jeanette D, Pahlow, Markus

Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
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Date Issued: 2016

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Ways of belonging: meanings of “Nature” among Xhosa-speaking township residents in South Africa

- Cocks, Michelle L, Alexander, Jamie K, Mogano, Lydia, Vetter, Susan M

Authors: Cocks, Michelle L , Alexander, Jamie K , Mogano, Lydia , Vetter, Susan M
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66021 , vital:28877 , https://doi.org/10.2993/0278-0771-36.4.820
Description: publisher version , The concept of biocultural diversity, originally used to describe indigenous people and their ways of using and managing natural resources, has more recently been applied within the urban context to understand the variability of interactions between humans and nature. Significant progress has been made internationally in acknowledging the need to preserve and maintain green spaces in urban environments. Current efforts to address the need for greening urban areas in South Africa primarily focus on the establishment and maintenance of botanical gardens and parks as well as various green belts within the urban landscape. South Africa's urban areas are overwhelmingly shaped by the historical segregation of space and stark disparities in wealth. The distribution, quality, and extent of urban green spaces reflect this. Many township dwellers do not have access to these amenities and their interactions with nature are thus usually constrained to access to municipal commonages. This article explores how areas of natural vegetation in municipal commonages on the outskirts of urban centers in South Africa continue to offer places of cultural, spiritual, and restorative importance to Xhosa-speaking township dwellers. A case study from Grahamstown, an urban center in the Eastern Cape with a population of around 80,000, illustrates how ability to access and move through such places contributes to people's well-being, identity formation, and shared heritage. A case is made for adopting a biocultural diversity approach to spatial planning and urban development within the South African context.
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Date Issued: 2016

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What lies beneath: exploring the deeper purposes of feedback on student writing through considering disciplinary knowledge and knowers

- Van Heerden, Martina, Clarence, Sherran, Bharuthram, Sharita

Authors: Van Heerden, Martina , Clarence, Sherran , Bharuthram, Sharita
Date: 2016
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/59856 , vital:27669 , https://doi.org/10.1080/02602938.2016.1212985
Description: Feedback plays an integral role in students’ learning and development, as it is often the only personal communication that students have with tutors or lecturers about their own work. Yet, in spite of its integral role in student learning, there is disagreement between how students and tutors or lecturers perceive the pedagogic purpose of feedback. Central to this disagreement is the role that feedback has to play in ensuring that students produce the ‘right’ kinds of knowledge, and become the ‘right’ kinds of knowers within their disciplines. This paper argues that, in order to find common ground between students and tutors or lecturers on what feedback is for, and how to both give and use it effectively, we need to conceptualise disciplinary knowledge and knowers anew. We offer, as a useful starting point, the Specialisation dimension of Legitimation Code Theory as both practical theory and methodological tool for exploring knowledge and knowers in English Studies and Law as two illustrative cases. The paper concludes that this analysis offers lecturers and tutors a fresh understanding of the disciplinary knowledge and knower structures they work within and, relatedly, a clearer view of the work their feedback needs to do within these.
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Date Issued: 2016

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Why a contextual approach to professional development?

- Leibowitz, B L, Vorster, Jo-Anne, Ndebele, C

Authors: Leibowitz, B L , Vorster, Jo-Anne , Ndebele, C
Date: 2016
Language: English
Type: article , text
Identifier: http://hdl.handle.net/10962/61288 , vital:28009 , https://journals.co.za/content/journal/10520/EJC-4ad93ec2a
Description: One of the peculiarities of the literature on academic professional development with regard to teaching is its a-political nature. It pays insufficient attention to issues of equity, and to how privilege, geographical location, class and ethnicity influence the way that staff in higher education learn to teach. This is surprising, or paradoxical, given the strong world-wide concern for widening participation and student success in higher education. The approaches towards professional academic development have been dominated by literature from the global North, which does not take into account conditions in resource-constrained environments. We contend that literature from these Southern environments enrich the international body of literature. Thus there is a need for scholarly writing on learning to teach in higher education, which takes a specifically social, contextual and relational approach and which considers these within resource-rich as well as resource-constrained environments.
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Date Issued: 2016

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Why a contextual approach to professional development?

- Leibowitz, B L, Vorster, Jo-Anne, Ndebele, C

Authors: Leibowitz, B L , Vorster, Jo-Anne , Ndebele, C
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/71141 , vital:29789 , https://doi.org/10.20853/30-6-714
Description: One of the peculiarities of the literature on academic professional development with regard to teaching is its a-political nature. It pays insufficient attention to issues of equity, and to how privilege, geographical location, class and ethnicity influence the way that staff in higher education learn to teach. This is surprising, or paradoxical, given the strong world-wide concern for widening participation and student success in higher education. The approaches towards professional academic development have been dominated by literature from the global North, which does not take into account conditions in resource-constrained environments. We contend that literature from these Southern environments enrich the international body of literature. Thus there is a need for scholarly writing on learning to teach in higher education, which takes a specifically social, contextual and relational approach and which considers these within resource-rich as well as resource-constrained environments.
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Date Issued: 2016

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Xenophilia in Muizenberg, South Africa: new potentials for race relations?

- Owen, Joy

Authors: Owen, Joy
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/147972 , vital:38698 , (http://anthrosource.onlinelibrary.wiley.com/hub/journal/10.1111/(ISSN)1548-744X/about/author-guidelines.html)
Description: Since the advent of democracy in 1994 race relations in South Africa have not improved substantially. The arrival of transmigrants from other African countries has emphasized a wounded South African psyche, as various xenophobic attitudes and attacks attest. However, a lesser known reality is the expression of xenophilia by South African women. In this article I argue that an intimate relationship between a South African coloured woman and a Congolese black man scripts a different potentiality for multiracial relations in the private and public spaces of urban Cape Town, South Africa.
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Date Issued: 2016

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‘Abagyenda bareeba. Those who Travel, See’: Home, Migration and the Maternal Bond in Doreen Baingana’s Tropical Fish

- Spencer, Lynda G

Authors: Spencer, Lynda G
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/139017 , vital:37696 , https://doi.org/10.1080/00020184.2016.1182319
Description: Doreen Baingana’s Tropical Fish explores the migratory experiences of the main narrator-focalizer, Christine Mugisha, as she travels from Uganda to the United States of America. Although the analyses of home, exile, and migration by writers like Edward Said and Paul Tiyambe Zeleza tend to be ungendered; Baingana seems to elaborate on these concerns by reflecting on the gendered experience of travel. As Carole Boyce Davies has argued, the act of travelling and migration opens up new spaces and possibilities for black women writers as they come into contact with multiple places and cultures. In their encounters with migration, black women are able to negotiate and re-negotiate their identities. This article focuses on how Tropical Fish, interrogates complex, contradictory, ambiguous and often conflicted questions of home and migration with their concomitant issues of belonging and alienation/ estrangement and how they are intimately tied to the maternal bond.
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Date Issued: 2016

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“A Step Towards Silence”: Samuel Beckett’s The Unnamable and the Problem of Following the Stranger

- Marais, Mike

Authors: Marais, Mike
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/144205 , vital:38320 , DOI: 10.1080/02564718.2016.1249617
Description: In this article, I argue that Samuel Beckett’s The Unnamable evinces the kind of aesthetic ambivalence that Theodor Adorno, in Aesthetic Theory, ascribes to the artwork’s location both in and outside of society. By tracing the metaphors used in the narrator’s depiction of the act of narration, I demonstrate that this novel self-reflexively articulates and meditates on its ambivalent position in society. Thereafter, I relate the work’s suspicion of its medium, and therefore its estrangement from itself, to its critique of community’s norms of recognition, which are embedded in language. Finally, I reflect on the potential effect of the text’s aesthetic ambivalence on the reader.
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Date Issued: 2016

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“Turn on” fluorescence enhancement of Zn octacarboxyphthaloyanine-graphene oxide conjugates by hydrogen peroxide

- Shumba, Munyaradzi, Mashazi, Philani N, Nyokong, Tebello

Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/240875 , vital:50881 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
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Date Issued: 2016

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“Turn on” fluorescence enhancement of Zn octacarboxyphthaloyanine-graphene oxide conjugates by hydrogen peroxide

- Shumba, Munyaradzi, Mashazi, Philani N, Nyokong, Tebello

Authors: Shumba, Munyaradzi , Mashazi, Philani N , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/190438 , vital:44994 , xlink:href="https://doi.org/10.1016/j.jlumin.2015.11.001"
Description: Zn octacarboxy phthalocyanine-reduced graphene oxide or graphene oxide conjugates were characterized by absorption spectroscopy, transmission electron microscopy, fluorescence spectroscopy, X-ray diffraction, thermo gravimetric analysis and X-ray photon spectroscopy. The presence of reduced graphene oxide or graphene oxide resulted in the quenching (turn on) of Zn octacarboxy phthalocyanine fluorescence which can be explained by photoinduced electron transfer. Zn octacarboxy phthalocyaninereduced graphene oxide or graphene oxide conjugates “turned on” fluorescence showed a linear response to hydrogen peroxide hence their potential to be used as sensors. The nanoprobe developed showed high selectivity towards hydrogen peroxide in the presence of physiological interferences.
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Date Issued: 2016

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