List of Titles

Morphological variations in southern African populations of Myriophyllum spicatum: Phenotypic plasticity or local adaptation?

- Weyl, Philip S R, Coetzee, Julie A

Authors: Weyl, Philip S R , Coetzee, Julie A
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/424789 , vital:72184 , xlink:href="https://doi.org/10.1016/j.sajb.2015.07.01"
Description: Variability in aquatic plant morphology is usually driven by phenotypic plasticity and local adaptations to environmental conditions experienced. This study aimed to elucidate which of these drivers is responsible for the morphological variation exhibited by three populations of Myriophyllum spicatum L. (Haloragaceae), a submerged aquatic plant whose status as native or exotic within southern Africa is uncertain. Individuals from three populations on the Vaal River (Northern Cape), Klipplaat River (Eastern Cape) and Lake Sibaya (KwaZulu-Natal) were grown under two nutrient treatments (high: 30 mg N/kg sediment and low: sediment only), while all other variables were kept the same. Morphological characteristics were measured at the start of the experiment to obtain a baseline morphology, and again eight weeks later. By the end of the experiment, the individuals from each population had responded to the different growing conditions. In most cases, the individuals from each population were significantly larger under the high nutrient treatment (Stem diameter: F(5,86) = 18.435, P is less than 0.001, Internode length: F(5,86) = 5.0747, P is less than 0.001, Leaf length: F(5,86) = 19.692, P is less than 0.001). Despite these differences in nutrient treatments, the growth pattern of each population remained true to the original starting point indicated by the lack of overlap between populations in the PCA groupings. This suggests that local adaptations are responsible for the differences in morphology between populations of M. spicatum, but shows that phenotypic plasticity does play a role as evidenced by individual responses to the different nutrient conditions. The development of these local adaptations within southern Africa suggests that the populations have had a long evolutionary history in the region and are relatively isolated with little reproductive mixing.
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Date Issued: 2016

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Mothers' experiences with regards to caring for their neotates following a caesarean section delivery

- Jikijela, Thobeka Pretty

Authors: Jikijela, Thobeka Pretty
Date: 2016
Subjects: Cesarean section , Maternal health services , Newborn infants -- Care
Language: English
Type: Thesis , Masters , MCur
Identifier: http://hdl.handle.net/10948/7493 , vital:21788
Description: The rate of caesarean section deliveries is increasing globally despite the World Health Organisation (WHO) recommendations not to exceed 15% of deliveries per year in each country. Furthermore, the commitment to baby-friendly hospital initiative puts a strain on mothers who must still take care of their neonates following a caesarean section delivery despite the pain experienced after surgery. It has been observed that pain management becomes a critical factor in the assistance of caesarean-section-delivered mothers in caring of their neonates otherwise mothers stay away from nursery or struggle with the neonate who is with her. The study aimed at exploring and describing the experiences of mothers with regard to caring for their neonates following a caesarean section delivery and developing objectives to: To explore experiences of mothers with regard to caring for their neonates following a caesarean section delivery and: To make recommendations to midwifery operational managers to assist mothers to cope better with caring of their neonates following a caesarean section delivery. The study used a qualitative, explorative, descriptive and contextual research design. Data was collected from eleven purposively selected mothers who had had a caesarean section delivery who were caring for their neonates in the post-natal wards in a public hospital in the Nelson Mandela Bay Municipal area. One-on-one, semi-structured interviews were conducted using a tape- recorder to capture them and writing of field notes to justify some of the themes or sub-themes identified. Data was analysed using data analysis method suggested by Creswell (2009:186). Trustworthiness was maintained through the standards of truth value, applicability, consistency and neutrality while ethical considerations were autonomy, beneficence and justice. From the findings it emerged that mothers had diverse experiences of pain following a caesarean section delivery. The mothers had also experienced physical limitations that hindered their ability to care for their neonates and themselves. Furthermore uncaring attitudes, shortage of staff and non-supportive services were experienced as contributing to mothers’ inability to breastfeed and taking care of themselves. Recommendations were for clinical nursing practice, nursing education and further research. Caesarean section delivery is painful and limiting to the mothers following surgery and demands extensive pain management and breastfeeding support. Managers need to address the contributing factors and develop strategies to assist the mothers cope better with pain.
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Date Issued: 2016

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Movement patterns of Cape stumpnose, Rhabdosargus holubi (Sparidae), in the Kowie Estuary, South Africa

- Grant, Gareth Neil

Authors: Grant, Gareth Neil
Date: 2016
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10962/982 , vital:20010
Description: Rhabdosargus holubi is an ubiquitous estuary-dependent fishery species endemic to southern Africa. Although aspects of its recruitment dynamics from sea to estuary have received considerable research attention, little is known about its movement behaviour within estuarine systems. Fishery surveys have also revealed that R. holubi is a dominant species in catches within several temperate estuaries in South Africa. Therefore, investigating movement behaviour is fundamental to understanding the ecology of this species and providing a means for implementing effective fisheries management strategies. This study made use of passive acoustic telemetry to quantify the movement patterns of juvenile R. holubi in the Kowie Estuary, in the Eastern Cape Province of South Africa. Previous studies have revealed that surgically implanted transmitters may have adverse effects on the physiology and behaviour of tagged fish. Therefore, due to the small size of juvenile R. holubi, an a priori transmitter-effect experiment was undertaken. This experiment revealed that juvenile R. holubi (146-217 mm fork length) were not adversely affected by the surgical implantation of acoustic transmitters (7 mm Ø, 1.6 g out of water) and hence acoustic telemetry was well suited to monitoring the movements of this species. A 4-month telemetry study evaluated the movement patterns of 21 juveniles (140-190 mm fork length) tagged in three equal batches along the length of the estuary. Specific aspects of their movement included space use patterns, habitat connectivity, and the influences of geophysical cycles and environmental variables. Tagged fish exhibited high residency, which varied between each release site area. The mean length of estuary used was greater for the upper batch (15.65 ± 6.49 km) than the middle and lower batches (7.36 ± 3.68 and 2.67 ± 2 km, respectively). In terms of habitat connectivity, once the tagged fish left the estuary, they generally did not return. Tagged R. holubi spent the majority (83%) of their monitoring periods within the estuarine environment, with the sea (16%) and riverine (1%) environments being utilised to a lesser extent. Diel and tidal cycles influenced the movement patterns of juvenile R. holubi. However, the high levels of residency meant that fine-scale movements were difficult to detect due to the acoustic receiver deployment configuration (i.e. receivers moored one kilometer apart). The influence of environmental variables on the movement of individuals, modelled with general linear mixed models (GLMMs), revealed that the effects of river inflow and water temperature were greatest. Increased river inflow caused individuals to use larger portions of the estuary. Increased water temperature, particularly river temperature, caused individuals to shift their distributions downstream (towards the mouth of the estuary). This study highlighted the importance of estuarine nursery habitats to R. holubi, suggesting that a loss or reduction of healthy estuarine habitats may lead to significant declines in the abundance of this species. Furthermore, extreme resident behaviour suggests that no-take area closures (estuarine protected areas) would be an effective management strategy for this important fishery species.
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Date Issued: 2016

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Multilingual education for Africa: Concepts and practices

- Kaschula, Russell H, Wolff, H Ekkehard

Authors: Kaschula, Russell H , Wolff, H Ekkehard
Date: 2016
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/174838 , vital:42513 , ISBN 978-0415315760 , https://www.amazon.com/Multilingual-Education-Africa-Practices-Routledge/dp/041531576X
Description: The common thread in this book is the exploration of innovative pedagogies in language teaching and language use in education. The greatest danger facing educators is one of complacency. Whether set in Zimbabwe, Ethiopia, South Africa or elsewhere in Africa, all the chapters in this book emphasise the imperative for educators to constantly revise curricula and teaching methods in order to find the most appropriate ways of teaching and using language in multilingual settings.
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Date Issued: 2016

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Multiple drivers of local (non-) compliance in community-cased marine resource management: case studies from the South Pacific

- Rohe, Janne R, Aswani, Shankar, Schlüter, Achim, Ferse, Sebastian C A

Authors: Rohe, Janne R , Aswani, Shankar , Schlüter, Achim , Ferse, Sebastian C A
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/70571 , vital:29676 , https://doi.org/10.3389/fmars.2017.00172
Description: The outcomes of marine conservation and related management interventions depend to a large extent on people's compliance with these rule systems. In the South Pacific, community-based marine resource management (CBMRM) has gained wide recognition as a strategy for the sustainable management of marine resources. In current practice, CBMRM initiatives often build upon customary forms of marine governance, integrating scientific advice and management principles in collaboration with external partners. However, diverse socio-economic developments as well as limited legal mandates can challenge these approaches. Compliance with and effective (legally-backed) enforcement of local management strategies constitute a growing challenge for communities—often resulting in considerable impact on the success or failure of CBMRM. Marine management arrangements are highly dynamic over time, and similarly compliance with rule systems tends to change depending on context. Understanding the factors contributing to (non-) compliance in a given setting is key to the design and function of adaptive management approaches. Yet, few empirical studies have looked in depth into the dynamics around local (non-) compliance with local marine tenure rules under the transforming management arrangements. Using two case studies from Solomon Islands and Fiji, we investigate what drives local (non-) compliance with CBMRM and what hinders or supports its effective enforcement. The case studies reveal that non-compliance is mainly driven by: (1) diminishing perceived legitimacy of local rules and rule-makers; (2) increased incentives to break rules due to market access and/ or lack of alternative income; and (3) relatively weak enforcement of local rules (i.e., low perceptions of risk from sanctions for rule-breaking). These drivers do not stand alone but can act together and add up to impair effective management. We further analyze how enforcement of CBMRM is challenged through a range of institutional; socio-cultural and technical/financial constraints, which are in parts a result of the dynamism and ongoing transformations of management arrangements. Our study underlines the importance of better understanding and contextualizing marine resource management processes under dynamic conditions for an improved understanding of compliance in a particular setting.
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Date Issued: 2016

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Nanocomposites of carbon nanomaterials and metallophthalocyanines : applications towards electrocatalysis

- Nyoni, Stephen

Authors: Nyoni, Stephen
Date: 2016
Subjects: Nanocomposites (Materials) , Nanostructured materials , Electrocatalysis
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4561 , http://hdl.handle.net/10962/d1020846
Description: Nanohybrid materials have been prepared and examined for their electrocatalytic activity. The nanocomposites have been prepared from carbon nanomaterials (multiwalled carbon nanotubes (MWCNTs) and graphene nanosheets), cadmium selenide quantum dots and metallophthalocyanines (MPcs). The MPcs used in this work are cobalt tetraamino-phthalocyanine (CoTAPc) and tetra (4-(4,6-diaminopyrimidin-2-ylthio) phthalocyaninatocobalt (II)) (CoPyPc). Their activity has also been explored in different forms; polymeric MPcs, iodine doped MPcs and covalently linked MPcs. The premixed drop-dry, sequential drop-dry and electropolymerisation electrode modification techniques were used to prepare nanocomposite catalysts on the glassy carbon electrode (GCE) surface. The sequential drop dry technique for MPc and MWCNTs gave better catalytic responses in terms of limit of detection, catalytic and electron transfer rate constants relative to the premixed. MWCNTs and CdSe-QDs have been used as intercalating agents to reduce restacking of graphene nanosheets during nanocomposite preparation. Voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy methods are used for electrochemical characterization modified GCE. X-ray photoelectron spectroscopy, X-ray diffractometry, transmission electron microscopy, scanning electron microscopy, infra-red spectroscopy, Raman spectroscopy were used to explore surface functionalities, morphology and topography of the nanocomposites. Electrocatalytic activity and possible applications of the modified electrodes were tested using oxygen reduction reaction, l-cysteine oxidation and paraquat reduction. Activity of nanocomposites was found superior over individual nanomaterials in these applications.
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Date Issued: 2016

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Nascent Desires: Gendered Sexualities in Life Orientation Sexuality Education Programmes and Popular Music

- Moodley, Dale Dhersen

Authors: Moodley, Dale Dhersen
Date: 2016
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:3274 , http://hdl.handle.net/10962/d1021260
Description: Formal school-based sexuality education is one medium, amongst others, that recognises young people’s sexuality, but usually as at-risk and/or risk taking subjects, or as innocent subjects. I analyse the gendered sexualities of young people as represented in: Grade 10 Life Orientation sexuality education programmes and popular music, as two mediums of sexual socialisation in Grade 10 learners’ lives, and as engaged with by Grade 10 learners and educators. I collected data from two schools in the Eastern Cape that included: (i) sections on sexuality from two Life Orientation manuals used by educators in classrooms: ‘Oxford Successful Life Orientation’ (2011), and ‘Shuters Top Class Life Orientation’ (2011); (ii) videos and lyrics of three songs voted most popular by learners which were ‘Climax’ by Usher, ‘Beez in the Trap’ by Nicki Minaj, and ‘Where Have You Been’ by Rihanna; (iii) observations of seven sexuality education classes; and, (iv) in-depth semistructured interviews conducted with eight learners and two educators. I draw on an integrated theoretical and methodological approach – Foucauldian, feminist poststructural and psychosocial psychoanalytic perspectives – to conceptualise and analyse gendered sexualities in terms of: (i) the dominant gendered discourses found in sexuality education manuals, and music videos and lyrics; (ii) the reflexive and interactive gendered subject positions taken up and/or resisted by learners and educators during classroom lessons and one-on-one interviews; and, (iii) learners’ and educators’ conscious and unconscious investments in particular gendered subject positions during one-on-one interviews. These three sets of analysis produced four major themes. The first theme centres on responsible sexuality; young women are expected to assume more sexual responsility than young men, thus curbing their sexual agency. The second theme outlines three types of pleasure – sexual, romantic and dating and/or relationship pleasure – that accord young men and women active and passive ways of exercising pleasure. The third theme highlights the heteronormative transitioning adolescent subject that constructs young women as reproductive subjects and young men as sexual subjects. The last theme focuses on gendered power relations and raunch culture, and maintains that young men are powerful and likely to commit acts of sexual violence against young women because they are powerless. The central argument developed when viewing all the themes is that dominant gendered discourse, gendered subject positions, and conscious and unconscious investments in these positions challenge the extent to which the gendered meanings that underpin adolescent learners’ sexuality are stable and fixed. The gendered discourses in the Life Orientation sexuality education programmes showed that gender is expressed rigidly, thus privileging masculine over feminine sexuality. However, the gendered discourses in the popular music contested rigid gender binaries and produced fluid and equitable masculine and feminine sexualities. The classroom practices depicted multiple and more equatable gendered sexualities, highlighting just how contested gender is. Finally, educator and learners’ personal biographies illustrated how conflicting masculine and feminine sexualities present a signficant source of emotional conflict for them. It may benefit policymakers and stakeholders to consider informal mediums of sexual socialisation for learners, such as music, when drafting the Life Orientation sexuality education curriculum, whilst also taking into account learners and educators personal lives.
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Date Issued: 2016

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Natural resource use, incomes, and poverty along the rural–urban continuum of two medium-sized, South African towns

- Ward, Catherine D, Shackleton, Charlie M

Authors: Ward, Catherine D , Shackleton, Charlie M
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/180790 , vital:43646 , xlink:href="https://doi.org/10.1016/j.worlddev.2015.10.025"
Description: Urbanization is a significant driver of global change, reshaping livelihoods, productive activities, and incomes. Yet, many elements of what are typically regarded as rural activities can be found in urban places and vice versa. We report on the incomes from land- and cash-based activities along the rural–urban gradient of two South African towns. Although the dominant income strategies varied, all households had more than one income source. Use of wild resources and agriculture were common in urban settings, although variable between and within towns. Poverty levels would be 5–10% higher in the absence of natural resource-based incomes.
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Date Issued: 2016

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Nature and source of suspended particulate matter and detritus along an austral temperate river–estuary continuum, assessed using stable isotope analysis

- Dalu, Tatenda, Richoux, Nicole B, Froneman, P William

Authors: Dalu, Tatenda , Richoux, Nicole B , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/68012 , vital:29181 , https://doi.org/10.1007/s10750-015-2480-1
Description: Publisher version , Ecologists are interested in the factors that control, and the variability in, the contributions of different sources to mixed organic materials travelling through lotic systems. We hypothesized that the source matter fuelling mixed organic pools in a river–estuary continuum varies over space and time. Samples of the mixed organic pools were collected along a small temperate river (Kowie River) in southern Africa during early and late spring, summer and winter. The C:N ratios of suspended particulate matter (SPM) collected during summer and winter indicated that the lower reaches of the system had similar organic matter contributions. Stable isotope analysis in R revealed that aquatic macrophytes were significant contributors to SPM in the upper reaches. Bulk detritus had large allochthonous matter components in the lower reaches, and contributions of aquatic macrophytes and benthic algae were high (>50%) in the upper to middle reaches. The evaluation of organic matter contributions to SPM and detritus along the river–estuary continuum provided a baseline assessment of the nature and sources of potential food for consumers inhabiting different locations during different seasons. Incorporating SPM and detritus spatio-temporal variations in food web studies will improve our understanding of carbon flow in aquatic systems.
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Date Issued: 2016

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Ndiyoyika

- Nyezwa, Mxolisi

Authors: Nyezwa, Mxolisi
Date: 2016
Language: English , Xhosa
Type: Thesis , Masters , MA
Identifier: vital:6021 , http://hdl.handle.net/10962/d1021245
Description: This thesis collection is a book of isiXhosa poems in three sections: - Poems derived and influenced by the rhythmic structure and the lyrics of Maskandi music - More introspective and personal poems derived from other influences: International poetry, South African poetry, and certain jazz and soul music - A major poem titled, “Nozala, umqolo wakho uphandle” which delves into the state of South Africa and explores the relationships that entrench poverty and powerlessness in post-apartheid South Africa. , Le thisisi yingqokelela yemibongo yesiXhosa eyohlulwe yazizigaba ezintathu: - Imibongo ephenjelelwe ziingoma nezingqi zomculo kaMaskandi - Imibongo ephenjelelwe zizimvo neemvakalelo zam njengombhali, ngakumbi iintshukumo zomzimba nezomphefumlo ezithundezwe ziimbongi zamazwe omhlaba, ezoMzantsi Afrika, kunye nemiculo efana ne-jazz, ne-soul - Umbongo ombaxa osihloko sithi, “Nozala, umqolo wakho uphandle” othetha ngelizwe lethu iMzantsi Afrika, uqwalasela indlela ekuphethwe ngayo ilizwe ziziphathamandla, nendlela abasemagunyeni abaphembelela ngayo intswela-ngqesho nentlupheko eluntwini, kwanokufiphala kobutsha-ntliziyo nobuthanda-zwe kubemi beli lizwe.
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Date Issued: 2016

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New evidence for the correlation of basalts of the Suurberg Group with the upper part of the Karoo basalt sequence of Lesotho:

- Marsh, Julian S

Authors: Marsh, Julian S
Date: 2016
Language: English
Type: text , book
Identifier: http://hdl.handle.net/10962/145122 , vital:38410 , ISBN 9783319408590 , https://link.springer.com/chapter/10.1007/978-3-319-40859-0_6
Description: Tholeiitic basalts build the Mimosa Formation, the uppermost stratigraphic unit of the Suurberg Group in the northern part of the Algoa Basin. Exposures are very poor and the tectonic significance of the Suurberg rocks and the origin of the Mimosa basalts are contentious. Drilling of stratigraphic boreholes at four localities allowed detailed sampling of the basalts from two cores 90 km apart for geochemical, age and palaeomagnetic investigations.
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Date Issued: 2016

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Nitrogen fertilisation improves growth of Chromolaena odorata (Asteraceae) and the performance of the biological control agent, Pareuchaetes insulata (Erebidae)

- Uyi, Osariyekemwen O, Zacharariades, Costas, Hill, Martin P

Authors: Uyi, Osariyekemwen O , Zacharariades, Costas , Hill, Martin P
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/416880 , vital:71393 , xlink:href="https://doi.org/10.1080/09583157.2015.1118615"
Description: Recent studies have demonstrated, through their contrasting results, that relationships between nitrogen levels in host plants and phytophagous insect performance are not simple. This study examined the effect of varying fertilisation regimes on the invasive alien plant, Chromolaena odorata (L.) (Asteraceae) and the response of a specialist folivore (a biological control agent), Pareuchaetes insulata (Walker) (Lepidoptera: Erebidae). C. odorata plants were treated with 3 different levels of fertilisation and plant characteristics were measured within 2–3 months of fertiliser application. Leaves from each of the three treatments were fed to newly hatched larvae until pupation in order to determine the effect of nitrogen fertilisation on herbivore performance metrics such as survival, development time, fecundity and longevity. High and medium fertilisation significantly increased foliar nitrogen concentrations, basal stem diameter, leaf length, shoot height and above-ground biomass of C. odorata plants relative to low fertilisation. When individuals of P. insulata were fed on leaves from medium- or high-fertilisation treatments, they developed faster, grew to a larger size (by 8%) and achieved higher fecundity (19–22%) than leaves from the low-fertilisation treatment. The results suggest that in mass-rearing, increased production of this biological control agent will occur in high- or medium-fertilised plants.
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Date Issued: 2016

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NMMU students' perceptions of their creativity

- Rogers, Angela Louise

Authors: Rogers, Angela Louise
Date: 2016
Subjects: Creative ability in business , Creative thinking , Educational innovations
Language: English
Type: Thesis , Masters , MBA
Identifier: http://hdl.handle.net/10948/8037 , vital:24478
Description: Creativity is seen as the driving force behind innovation. It can even be said to be the same process. It is critical to implement the creativity in order for innovation to actually take place. This combination of creativity and innovation is required for economic growth, sustainability, continuous improvement and competitive edge for organisations. Creativity is more than just artistic ability but includes scientific and problem solving steps and basic everyday creativity. This combination would be key in government departments, organisations and universities today. People’s perception on creativity could hamper their growth and development in this key area, not only for themselves but of others that they come into contact with. People’s perception on creativity is that it is either a genius form in either artistic or musical terms or it is not at all creative. They do not necessarily view the everyday tasks as creative. The research approach for this study is positivistic and deductive. The students’ perception of creativity is gathered using a quantitative questionnaire, where they rank their perceptions. The questionnaire was from an international study and it was made available to all students at the Nelson Mandela Metropolitan University. The data analysis will be both descriptive and inferential in nature. The research seeks to examine students’ perception of their own creativity and how they rate various creative products or services. Students are on their way to the pinnacle in their fields and the creativity should therefore be at its peak to be able to take full advantage and to get maximum benefit from it. The research will gain insight into their perception via a questionnaire where they need to rate themselves. The literature review will investigate creativity, innovation and the links between them. It will analyse the importance of innovation to business and the unlocking of creativity. There are many differing ways to unlock and stimulate creativity and some of these are addressed.
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Date Issued: 2016

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Nonlinear optical behavior of alkyne terminated phthalocyanines in solution and when embedded in polysulfone as thin films: effects of aggregation

- Bankole, Owolabi M, Yilmaz, Yusuf, Nyokong, Tebello

Authors: Bankole, Owolabi M , Yilmaz, Yusuf , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/189110 , vital:44817 , xlink:href="https://doi.org/10.1016/j.optmat.2015.11.041"
Description: We report here for the first time, on the comparative studies of the photophysical and optical limiting behavior of our two novel phthalocyanines namely 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyanines 2, and 2(3), 9(10), 16(17), 23(24)-tetrakis-(4-(5-methylhex-1-yn-3-yloxy)) phthalocyaninato zinc (II) (3) in solution and thin films. Nonlinear optical (NLO) properties of the samples in solution and contained in polysulfone (PSU) thin films were evaluated using Z-scan technique at 532 nm and 10 ns pulsed duration. Effects of aggregation and disaggregation on the NLO performance of metal-free phthalocyanine are reported in detail. Our findings showed that the prepared Pcs show larger nonlinear absorption coefficient and lower limiting thresholds when embedded in polysulfone films compared to in solutions. The values of nonlinear susceptibility and hyperpolarizability recorded for 3-PSU in this work are respectively, ∼2.09 × 10−8 esu and ∼1.02 × 10−26 esu. These values are among the largest values reported for phthalocyanines and other macrocycles doped on polymer matrices.
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Date Issued: 2016

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Nonlinear optical behavior of neodymium mono-and bi-nuclear phthalocyanines linked to zinc oxide nanoparticles and incorporated into poly acrylic acid

- Sekhosana, Kutloana E, Amuhaya, Edith K, Nyokong, Tebello

Authors: Sekhosana, Kutloana E , Amuhaya, Edith K , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/188766 , vital:44783 , xlink:href="https://doi.org/10.1016/j.poly.2015.12.045"
Description: Syntheses of bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24))-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) and 2(3), 9(10), 16(17), 23(24)-(tetrapyridin-3-yloxy phthalocyaninato) neodymium (III) acetate (4) as well as their conjugates with ZnO nanoparticles (conjugates 6, 7 and 8) are presented. Thin films of conjugate 6 (where complex 3 is linked to ZnO nanoparticles via an amide bond) gave the best third-order susceptibility (5.89 × 10−8 esu), second-order hyperpolarizability (2.53 × 10−25 esu) and the lowest limiting threshold values (0.12 J cm−2). The nonlinear behavior is enhanced in solid state when compared to solution.
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Date Issued: 2016

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Nonlinear optical response of a low symmetry phthalocyanine in the presence of gold nanoparticles when in solution or embedded in poly acrylic acid polymer thin films

- Bankole, Owolabi M, Nyokong, Tebello

Authors: Bankole, Owolabi M , Nyokong, Tebello
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/188719 , vital:44779 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.12.014"
Description: In this article, we explored the photophysical and nonlinear optical (NLO) characterizations of low symmetry phthalocyanine (ZnPc-NH2) covalently linked to MPA-capped AuNPs (ZnPc-NH2-AuNPs) and poly acrylic acid (ZnPc-NH2-PAA). Nonlinear optical (NLO) properties of the samples were evaluated using Z-scan technique at 532 nm and 10 ns pulsed duration. We observed enhanced photophysical and nonlinear optical behaviour for the ZnPc-NH2 in presence of AuNPs. By virtue of the magnitude of absorption coefficients and other NLO optical parameters estimated in this work, ZnPc-NH2-AuNPs was found to exhibit improved nonlinear optical response compared to the ZnPc-NH2 and ZnPc-NH2-PAA. Both ZnPc-NH2-AuNPs and ZnPc-NH2 doped in PAA possess strong nonlinear absorption coefficients and very low limiting thresholds than when measured in solution.
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Date Issued: 2016

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