Employing safe bets: reflections on attracting, developing and retaining the next generation of academics
- Authors: Hlengwa, Amanda I
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/142145 , vital:38053 , ISBN 9781869142902 , https://books.google.co.za/books?id=49o8rgEACAAJanddq=Being+at+home:+Race,+institutional+culture+and+transformation+at+South+African+higher+education+institutionandhl=enandsa=Xandved=0ahUKEwiPgsa6mpjjAhXNN8AKHbNwAtoQ6AEIKDAA
- Description: This edited work has gathered together contributions on how to transform universities in South Africa; as many are struggling to shift their institutional culture. In a South African context, transformation means to attempt to change higher education institutions such that they no longer reflect the values promoted by apartheid but rather reflect the values embodied in South Africa's 1996 Constitution. Institutional culture is the main subject for discussion in this book. In order to transform South Africa's universities, the contributors begin by analyzing the idea of what a university is, and relatedly, what its ideal aims are. A second theme is to understand what institutional culture is and how it functions. Moreover, transformation cannot occur without transforming the broader cultures of which they are a part. Related to this theme is a general concern about how contemporary moves towards the instrumentalization of higher education affect the ability to transform institutions. These institutions are being pushed to conform to goals that are outside the traditional idea of a university, such as concerns that universities are being 'bureaucratized' and becoming corporations, instead of a place of learning open to all. In conclusion it can be said that the contemporary South African academic community has an opportunity to recreate itself as the end of apartheid created space for engaging in transformative epistemic projects. The transformation of the tertiary sector entails a transformation of institutional cultures.
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Enhanced optical limiting behaviour of indium phthalocyanine derivatives when in solution or embedded in poly (acrylic acid) or poly (methyl methacrylate) polymers
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189445 , vital:44847 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.02.003"
- Description: The optical limiting performance of indium phthalocyanine-based polymer thin-films with large nonlinear absorption coefficients (βeff) and low limiting threshold intensity (Ilim) are described. The absorption cross-sections and the population dynamics of the excited states are also reported. The excited state absorption cross-sections (σexc) are shown to depend on the transition moment between the T1 and T2 states. βeff values have been shown to be related to the population density of the molecules in the T1 state. The improved optical limiting performance recorded for the investigated phthalocyanine complexes in the presence of polymer matrices has been attributed to the aggregation effects of the complexes in the polymer thin-films. The optical properties of the indium phthalocyanine moieties were found to possess robust sensitivity to a change of the polymer materials.
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Enhanced triplet state parameters for zinc carboxy phenoxy phthalocyanine following conjugation to ascorbic acid
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189348 , vital:44839 , xlink:href="https://doi.org/10.1016/j.poly.2015.01.032"
- Description: Zinc phthalocyanine bearing four ascorbic acid units (formed via ester bond between zinc carboxy phenoxy phthalocyanines and ascorbic acid) was synthesized and characterized using different spectroscopic methods. The complex (with or without ascorbic acid) was further adsorbed onto single walled carbon nanotubes (SWCNTs) and further characterized using Raman spectroscopy, X-ray diffractometry, transmission electron microscopy and thermogravimetric analysis. The photophysical properties of the complexes were studied. The synthesized complex showed better photophysical properties when compared to the carboxy phenoxy phthalocyanines alone, this is evident in the increase of the triplet quantum yields (ΦT), triplet life-times (τT) and singlet oxygen quantum yields (ΦΔ). The zinc phthalocyanines bearing ascorbic acid showed improved triplet life-times even in the presence of SWCNTs.
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Enhanced triplet state yields in aqueous media of asymmetric zinc phthalocyanines when conjugated to silver nanoflowers
- Authors: D'Souza, Sarah , George, Reama , Göksel, Meltem , Atilla, Devrim , Durmus, Mahmut , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189099 , vital:44816 , xlink:href="https://doi.org/10.1016/j.poly.2015.08.017"
- Description: Novel low symmetry water-soluble zinc phthalocyanines (ZnPcs, complexes 1 and 2) were synthesized and then mixed with silver nanoflowers. Photophysical and photochemical studies were performed in order to determine the efficiency of complexes 1 and 2 as photosensitizers when alone and when combined with the silver nanoflowers. The Pcs show low fluorescence quantum yields and excellent triplet quantum yields of 0.78 (for 1) and 0.66 (for 2) in aqueous media. The triplet quantum yield values increased to 0.80 and 0.89, respectively, in the presence of silver nanoflowers. Long triplet lifetimes ranging from 180 to 200 μs in DMSO were obtained for complexes 1, 2 and their conjugates with silver nanoflowers.
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Enhancing cloud connectivity among NRENs in the SADC region through a novel institution cloud infrastructure framework
- Authors: Suresh, Nalina , Mbale, Jameson , Terzoli, Alfredo , Mufeti, Tulimevava K
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430592 , vital:72702 , 10.1109/ETNCC.2015.7184830
- Description: It is increasingly being recognized that faster socioeconomic develop-ment in Africa is dependent upon the development of Information and Communication Technology (ICT) Infrastructure for the dissemination of data and educational services. The scalability and flexibility provided by Cloud services in terms of resource management, service provisioning and virtualization makes it an attractive system for use with educational and ICT services. The flexibility of pay-as-you-go models combined with the ability to scale computing, storage and/or networking resources makes Cloud computing an ideal candidate for use with education, re-search and scientific infrastructures. Notwithstanding its benefits, transi-tioning from a traditional IT infrastructure to a Cloud computing para-digm raises security concerns with respect to data storage, data trans-mission and user privacy. This paper presents on-going research for the development of Science, Technology and Innovation (STI) infra-structure for the distribution of Information Communication technologies (ICT) services in the African context. The Inter-Cloud Infrastructure Framework (ICIF) proposed, is conceived as a Cloud computing framework suitable for use with National Research and Education Net-works (NRENs) in the SADC region. The ICIF system is used to create an Inter-Cloud infrastructure, and helps NRENs transition from tradi-tional IT infrastructure systems to the Cloud computing paradigm. It also provides new functional/operational components and Cloud services to support the interconnection and/or interoperability among SADC NRENs through the ICIF infrastructure.
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Environmental conflict resolution: a critical analysis of the role of interests and value
- Authors: Mweshi, John
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/55842 , vital:26740
- Description: This thesis intends to contribute to an enhanced understanding of environmental conflicts and their resolution. To accomplish this task the thesis will ascertain the role that value and interests play in environmental conflicts in order to establish an adequate basis upon which they can be resolved. In the process, the thesis will also examine three different approaches, namely, the Standard Approach; the Environmental Impact Assessment (EIA) framework; and the Structured Decision Making (SDM) approach. First, the standard approach is informed by the understanding that focusing on interests instead of human values makes the resolution of conflicts more tractable. In contrast, this thesis argues that an exclusive focus on interests, in the context of environmental conflict resolution, is inadequate in some important respects because there are other factors to be considered such as the environmental impacts at the root of the conflict. Second, the thesis examines the focus on impacts that characterises EIAs. It argues that this approach remedies the limitations of the standard approach insofar as impacts are understood in terms of object value. However, the EIA approach does not provide much guidance on how to deal with conflicting human values. Third, taking into account the fact that the standard approach does not address the question of object value, while the EIA addresses object value but does not deal directly with human values, the thesis examines the SDM approach to environmental risk decisions. The thesis argues that while the SDM approach claims to deal with conflicts involving human values head-on, it does not provide a viable alternative in terms of environmental conflict resolution. This is because it fails to recognise the key distinction between human values and object value despite acknowledging the presence of multiple value dimensions as a major obstacle to value trade-offs and therefore to the resolution of value conflicts. Finally, the thesis recommends an adequate basis upon which environmental conflicts can be resolved.
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Establishment of human OCT4 as a putative HSP90 client protein: a case for HSP90 chaperoning pluripotency
- Authors: Sterrenberg, Jason Neville
- Date: 2015
- Subjects: Induced pluripotent stem cells , Heat shock proteins , Stem cells , Transcription factors , Molecular chaperones
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194010 , vital:45415 , 10.21504/10962/194010
- Description: The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
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Evaluating coverage of the environment: a comparative study of the observations of academics and journalists
- Authors: Koro, Emmanuel
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/64888 , vital:28628
- Description: This study is a comparative analysis of the way that academics and journalists evaluate media coverage of news about the environment. The purpose is to gain insight into the kind of contributions that each of these groups can make to debates about the role that such coverage should play within processes of public deliberations about the environment. The dissertation begins by establishing theoretical terms of reference for assessing discussions of the journalistic coverage of the environment. It proposes that it is of value to consider the conceptualisation, within such discussions, of credible knowledge about the environment and, more particularly, to establish whether such conceptualisation is based within a positivist, interpretive, or critical realist paradigm. It is demonstrated that each of these epistemological traditions brings valuable perspectives to the discussion of journalism about the environment within such literature. It is, however, the positivist perspective that remains dominant, and this limits the extent to which the potential of the other two epistemological positions are fully realized. It is also demonstrated that there is a tendency, within this literature, to focus on the performance of individual journalists with minimal attention to the particularities of institutional and social context. It is proposed that this tendency results from the adherence to a positivist approach to the evaluation of journalism. The dissertation then describes the design and implementation of the empirical component of the study - dealing with decisions made about the overall methodological framing, the choice of method, the fieldwork plan and the approach to analysis. It is explained that the aim of the empirical component was to examine South African print journalists’ discussions of coverage of the environment in their own publications, and to compare such discussion to that which is represented in the academic literature. The dissertation then presents a summary of the themes that emerged from the analysis of the interview material that formed part of this empirical work. It is demonstrated that the evaluation of coverage of the environment, as articulated by the research participants, is informed by many of the assumptions and values that can be identified within academic literature. Such evaluation is, furthermore, similarly informed by a positivist, interpretive and critical treatment of knowledge - with, again, a tendency for the positivist position to dominate. One important difference is that the research participants include more references to institutional context. It is proposed, however, that the tendency to prioritise a positivist epistemological framing continues to place limitations on the extent to which the participants are able to fully articulate their knowledge about such context.
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Evaluation of microinsurance distribution strategy at the bottom of the pyramid by Liberty Life Swaziland
- Authors: Lukhele, Mlungisi Reginald
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/54474 , vital:26568
- Description: This is a qualitative study which focuses on how Liberty Life Swaziland distributes microinsurance to the bottom of the pyramid within Swaziland. Using stratified purposive sampling, this study identified 5 managers within Liberty Life and 4 managers from brokerages and affinity partners who had a minimum of 3 years’ experience in distribution of microinsurance. Semi-structured and in-depth interviews were conducted by the researcher with these managers. Interviews were stopped when there was data saturation. To induce emerging themes from the data, open-coding and constant comparison technique was used. Findings in this study reveal that to distribute microinsurance to low income households, Liberty Life objectives are to; (1) provide relevant solutions in a cost effective manner, thus keeping premiums as affordable as possible, (2) provide simple products which are easy to understand by customers, (3) make services accessible, and (4) make doing business easy. In this regard, Liberty Life distribution strategy is to partner with bulk retailing entities that have a client base they already service and benefit from nationwide presence and infrastructure. Lastly, the perspectives of both internal and external stakeholders in microinsurance are discussed to evaluate the challenges and successes experienced in implementing the distribution strategy. This study is valuable to critically understand the current distribution strategy from the viewpoint of key intermediaries, but also pinpoint how efforts to achieve microinsurance distribution objectives can be enhanced. Lastly, the study recommends that; a selection criteria be set for distribution partners, partnership with mobile network operators, investment in continuous training of distribution partners and knowledge sharing between Liberty and intermediaries to cease the opportunity at the bottom of the pyramid.
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Evaluation of teaching and courses: reframing traditional understandings and practices
- Authors: Belluigi, Dina Z
- Date: 2015
- Language: English
- Type: Book , text
- Identifier: http://hdl.handle.net/10962/59546 , vital:27625
- Description: This anthology outlines case studies which have emerged from an approach to evaluation which enables individual academics to practice a degree of autonomy in how they determine their own evaluation agendas, methods and approaches. This has enabled individual cases of both rigour and creativity when it comes to the collection of data and generation of feed- back on their teaching and/or courses, particularly in relation to transforming curricula responsively; enabling student voice and increasing student ownership; and creating spaces for practices to be challenged. The purpose of the case studies is pedagogic and to illustrate a range of practices and principles. For the sake of clarity some of the details have been omitted or slightly changed.
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Exploring contradictions and absences in mobilizing ‘learning as process' for sustainable agricultural practices
- Authors: Pesanayi, Tichaona
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437008 , vital:73323 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: Water is a fascinating, life-giving being. It flows. It cuts into the earth to create its passage by finding the places where the earth will give. As it meanders it passes through many different contexts, whether at a fastrush-full-blown flood or the trickle of an underground desert stream. It does not demand that the space it moves through is homogenous. It adapts to whatever terrain it finds itself journeying through. Human creatures, dependent as they are on water for their own beings and for life, flock to water like flies to food. We build our cities, our factories and homes on the banks and corners of rivers and draw and drink and use (and abuse) water. We throw in and we take out and the river keeps going until sometimes it doesn’t. Then we worry. Sometimes it is not the lack of flow that worries us but the fact that when we drink it babies become sick, some die and this causes a stir. In South Africa this security, or lack of it, is embedded in the political historical landscape of this land. Water is classified as scarce. Our rainfall is low in comparison to other countries. In South Africa, during apartheid this scarce resource was not avail able in equal measure to all. The rulers of apartheid South Africa were farmers and miners. They were of British decent, sent to farm the new colony. They were also descended from first colonial settlers arriving from the Nether-lands and then Germany, known colloquially as the Boers. South Africa was divided and redivided until in 1948 the Boers gained independence from British rule and finished the job that the British had started by legalizing the separation of races. Farming was still core to the Boer way of life and this is reflect-ed in the laws that dictated resource use and management, such as the 1956 Water Act No. 54 (RSA, 1956) which gave riparian rights to those that owned land. Water was also subsi-dized to boost the economy, particularly for the large mines, and parastatals such as Eskom (Byrnes, 1996). Water was not only used to ensure that the economy of white South Africa flourished, it also was the landmark of division.
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Exploring critical realist insights into transformative environmental learning processes in contexts of social-ecological risk
- Authors: Schudel, Ingrid J
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437045 , vital:73326 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: Environment and sustainability are continually recognized for significance to the future of planetary well-being. But the com-plex, cross-cutting transversal nature and associated ‘new-ness’1 of environment and sustainability concerns within edu-cation and training systems raise a number of challenges for education and training systems. In this chapter I explore how critical realist dialectics can help to more fully explain the ab-sence of intermediate pathways in the environment and sus-tain able development ‘sector’ in South Africa and through this analysis raise opportunities for creating more seamless envi-ronmental learning pathways into green jobs, enhancing social justice potential and public good concerns. The chapter situ-ates the discussion within the South African policy discourse of meaningful learning pathways (DHET, 2010) through a study of two priority scarce skills occupations in the environmental sector (environmental scientist and environmental technician). This is used as an example to illustrate systemic disjunctures that demonstrate how environmental learning pathways in and for sustain able development emerge. Using a critical realist lens to understand the absences that denote a relationship away from being allows the chapter to conceptualize absence as central to the real and hence to being (Lotz-Sisitka and Ramsarup, 2012; Bhaskar, 1993). Privileging absence allows me to develop a vantage point that connects being to becom-ing and hence underlines the intent for change inherent within this research. Norrie (2010, p. 28) states that ‘understanding change as a process of absenting of absences as well as the absenting of those structural constraints that keep absences in place . . . lies at the core of change’.
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Exploring patterns of Facebook usage, social capital, loneliness and well-being among a diverse South African student sample:
- Authors: Young, Charles , Strelitz, Larry N
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143705 , vital:38275 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: There has been much debate over whether the use of social network sites isolate people and truncate their relationships or alternatively, provide beneficial connections with others. This debate has been framed by a growing international literature which explores the triadic relationship between the intensity of use of Facebook to the maintenance of social capital and in turn the relationship between social capital and wellbeing and loneliness. A random list of 1168 Rhodes University students was drawn from the total student body and invited to participate in an online survey. In total, 491 students completed the survey (42% response rate). Hierarchical regression analyses demonstrate that intensity of Facebook usage adds a very small contribution to social capital, is very weakly associated with loneliness, and is not associated with wellbeing. Results contrast with international studies that fail to recognise the extent to which race and class cleavages impact on access to and use of social media.
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Exploring the emancipatory potential of nursing practice in relation to sexuality: a systematic literature review of nursing research 2009-2014
- Authors: Nhamo-Murire, Mercy , Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143650 , vital:38270 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Nurses play an important role in disseminating health information and in the provision of counselling concerning sexuality healthcare settings. There is some evidence, however, that nurses do not always consider issues relating to sexualities in their general practice, and when they do, may feel some discomfort in addressing sexuality. In this paper we report on a systematic review of research on nursing practice in relation to sexualities that appeared in nursing journals in the Web of Science database from 2009-2014. Thirty nine articles, which were published in English and reported on nursing practice in relation to sexualities, were thematically analysed. We focus on what research has been done and how this research may be used in the development of emancipatory nursing practice in relation to sexualities. Despite increasing attention being paid to social justice issues in nursing, the implications of this for nursing practice needs further exploration.
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Facile synthesis, spectroscopic and electrochemical properties, and theoretical calculations of porphyrin dimers with a bridging amide-bonded xanthene moiety
- Authors: Liang, Xu , Xu, Li , Li, Minzhi , Mack, John , Stone, Justin , Nyokong, Tebello , Jiang, Yu , Kobayashi, Nagao , Zhu, Weihua
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241390 , vital:50935 , xlink:href="https://doi.org/10.1142/S1088424615500492"
- Description: A free base porphyrin dimer bridged by a flexible amide-bonded xanthene moiety and its binuclear zinc(II) complex zinc(II) complex were synthesized and characterized. Structural characterization by MS and 1H NMR spectroscopy confirmed the bridged porphyrin dimer structure. The properties of the dimers were characterized by IR, UV-visible absorption, fluorescence and magnetic circular dichroism (MCD) spectroscopy, and electrochemistry studies. Theoretical calculations were carried out to analyze the electronic structures of porphyrin dimers with a bridging amide-bonded xanthene moiety.
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Fish utilization of surf-zones. Are they changing? A case study of the sheltered, warm-temperate King’s Beach
- Authors: Rishworth, Gavin M , Strydom, Nadine A , Potts, Warren M
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124504 , vital:35619 , https://doi.org/10.1080/15627020.2014.11407616
- Description: Surf-zone fish communities and their shifts over time are generally poorly understood. The aim of this study was to compare the current surf-zone fish assemblage at King’s Beach, South Africa, to a similar study conducted three decades ago, before the collapse of many exploited shore fishes in the region. Beach seine nets (mesh sizes of 10 and 50 mm) were used to target juvenile and adult fishes bimonthly from February to August 2011 over the high tide around sunset. A total of 14 species were recorded in both the 30mand 100mseine nets. The catch in these seine nets was dominated by Pomadasys olivaceus and Liza richardsonii, and this was significantly different to three decades ago, when P. olivaceus, Sarpa salpa and Diplodus capensis dominated the catch. Important linefish species belonging to the Sparidae and Sciaenidae families were significantly smaller and less abundant in this study. Two sparids, S. salpa and Lithognathus mormyrus, which made a large contribution to the surf-zone catch three decades ago were absent during this study. Reasons for the significant shifts in the surf-zone fish community, including overexploitation of the linefish and potential habitat modification, are discussed.
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Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193598 , vital:45351 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
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Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles
- Authors: Mthethwa, Thandekile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189865 , vital:44941 , xlink:href="https://doi.org/10.1016/j.jlumin.2014.09.005"
- Description: Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs.
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Fluorescence Behaviour of an Aluminium Octacarboxy Phthalocyanine-NaYGdF 4
- Authors: Taylor, Jessica , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189503 , vital:44852 , xlink:href="https://doi.org/10.1007/s10895-015-1539-8"
- Description: Using a methanol assisted thermal decomposition approach, sphere shaped NaYGdF4:Yb/Er upconversion nanoparticles (UCNPs) were successfully synthesized. The chemical, spectroscopic and fluorescence properties of the UCNPs were fully characterized. Characteristic upconversion fluorescence emissions were produced by the NPs in the green, red and NIR regions and the NPs were also shown to possess paramagnetic properties. The influence of the UCNPs on the spectroscopic and fluorescence properties of an aluminium octacarboxy phthalocyanine AlOCPc was investigated. Covalent conjugation to an AlOCPc resulted in a large blue shift of the phthalocyanine’s Q band, which was accompanied by a decrease in the Pc’s fluorescence lifetime in DMSO. By combining the phthalocyanine and upconversion nanoparticle, we present a system capable of multimodal imaging, using both the upconversion nanoparticle’s and phthalocyanine’s emission, and magnetic resonance imaging (as a result of doping the upconversion nanoparticles with Gd3+ ions).
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Food on the Table: Human Responses and Changing Coastal Fisheries in Solomon Islands
- Authors: Albert, Simon , Aswani, Shankar , Fisher, Paul L , Albert, Joelle
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/421887 , vital:71893 , xlink:href="https://doi.org/10.1371/journal.pone.0130800"
- Description: Globally the majority of commercial fisheries have experienced dramatic declines in stock and catch. Likewise, projections for many subsistence fisheries in the tropics indicate a dramatic decline is looming in the coming decades. In the Pacific Islands coastal fisheries provide basic subsistence needs for millions of people. A decline in fish catch would therefore have profound impacts on the health and livelihoods of these coastal communities. Given the decrease in local catch rates reported for many coastal communities in the Pacific, it is important to understand if fishers have responded to ecological change (either by expanding their fishing range and/or increasing their fishing effort), and if so, to evaluate the costs or benefits of these responses. We compare data from fish catches in 1995 and 2011 from a rural coastal community in Solomon Islands to examine the potentially changing coastal reef fishery at these time points. In particular we found changes in preferred fishing locations, fishing methodology and catch composition between these data sets. The results indicate that despite changes in catch rates (catch per unit effort) between data collected in 2011 and 16 years previously, the study community was able to increase gross catches through visiting fishing sites further away, diversifying fishing methods and targeting pelagic species through trolling. Such insight into local-scale responses to changing resources and/or fisheries development will help scientists and policy makers throughout the Pacific region in managing the region’s fisheries in the future.
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