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Physicochemical behavior of nanohybrids of mono and tetra substituted carboxyphenoxy phthalocyanine covalently linked to GSH–CdTe/CdS/ZnS quantum dots
No full textZinc monocarboxyphenoxy and tetracarboxyphenoxy phthalocyanines were covalently linked with three different sizes of glutathione capped core/shell/shell {CdTe/CdS/ZnS(4.2), CdTe/CdS/ZnS(5.1) and CdTe/CdS/ZnS(6.7)}; a core shell {CdTe/CdS(3.1)} and core {CdTe(2.4)} quantum dots. The physicochemical behavior and Förster resonance energy transfer (FRET) processes of the nanohybrids were investigated. The highest FRET efficiency was observed with CdTe/CdS/ZnS(6.7) nanohybrids with 98% and the least efficiency was observed with CdTe(2.4) nanohybrids with 85%. The CdTe/CdS/ZnS(6.7) also showed the best physicochemical behavior. These good physicochemical properties make the synthesized nanohybrids viable photosensitizers.Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.10.02
Optical properties of water-soluble l-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells
No full textAlloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing l-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed l-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.Original publication is available at http://dx.doi.org/10.1016/j.optmat.2015.05.02
An investigation into the perceptions of female academics on their career development: a comparative study of South African and Zimbabwean universities.
No full textThis study investigated the perceptions of female academics on their career development in South African and Zimbabwean universities. The study attempted to unravel the story of the female academics which must be heard but is seldom accorded the space within the academia. The interpretive paradigm was utilised in
this study because it focuses on individual perceprtions and experiences. In addition a qualititative approach was employed for the collection of data since it allowed for triangulation of data collection techniques so as to gain in-depth and rich information on the career trajectory of female academics in South African and Zimbabwean universities. Therefore, semi- structured interviews, focus group interviews and document analysis were employed. The participants were purposively selected for the sample of this study and comprised of 5 senior female academics from each university and 5 junior female academics also representing each university respectively. Thematic content analysis was used to analyse data and this was carried out in line with the research questions, aims and objectives of the study. Through the participants' answers from both universities under study, a transcript was formulated, coded and categorised in view of the career development of female academics in South African and Zimbabwean universities. It was discovered from the data that the female academics still encounter a number of challenges with regard to their career mobility both in and out of academia inter alia, (1) gender stereotyping and male domination (2) knowledge retention (3) lack of mentorship and organisational support especially through funding and professional staff development programmes (4) lack of female solidarity (5) under-representation of female academics (6) teaching workloads and research publications and (7) lack of family support, were illuminated by the participants as common fixtures that hinder their career development in academia. Moreover, there were variances in both universities under study especially with relations to funding, gender policies in place and male domination. Consequently, the above mentioned factors were more pronounced in Zimbabwean universities than in South African universities. As a result, emphasis was that both South African and Zimbabwean universities have to draw a line between theory and practice especially on the professional staff development programmes that are offered to the academics. A crucial observation was made by the researcher on how most of the participants from both universities under study had negotiated their roles as mothers, wifes, academic and sisters in a bid to realise career growth, such that striking a balance between work and family posed a continuous hindrance their career development. As a result, hard work, commitment, confidence, self-assertiveness and sacrifice cut across both universities as strategies used if the battle of career development of female academics had to be won. In sum, this study attempted to illuminate the perceptions and experiences of female academics and what it means to be a female academicin the 21st century universityn and why there is a need to create, cultivate and have a conducive and supportive working environment. Moreover, promotion of knowledge expansion and sharing, gender equity and equality needs to be employed by both universities under research. Additionally, the professtional staff development programmes offered need to be conducted by qualified and experienced personnel in a bid to avoid repetition of workshops and training programs. Furthermore, formalisation of mentoring and role modelling should also be employed by South African and Zimbabwean universities. Lastly, the study recommended that there is a need for universities source out resources for its academics if there are to
produce well rounded scholars who will be able to experience career development.
KEY WORDS: Perceptions, Career Development, Female academics, Universitie
Exploring the uses of mental skills by competitive road running athletes
No full textResearch on athletes has shown that mental skills are an important component of being a successful athlete. The importance of these mental skills is seen in the number of athletes who have formally started training using mental skills training programmes (MST) according to the literature. The study of mental skills in South Africa lags behind other countries like USA, UK and Sweden. This particular study explored the use of mental skills by road running athletes. The study was conducted with six competitive marathon athletes. Semi-structured interviews were conducted as part of an elaborate qualitative methodology design. The data collected from these semi-structured interviews was analysed using thematic analysis. The results show that road running athletes use mental skills that include; mental rehearsal, planning, goal setting and self-talk. The athletes in this research showed the importance of mental skills and it is recommended that formal training in these mental skills will be highly beneficial not only to road running athletes but for all South African sports people in genera
A study of barred preferential arrangements with applications to numerical approximation in electric circuits
No full textIn 1854 Cayley proposed an interesting sequence 1,1,3,13,75,541,... in connection with analytical forms called trees. Since then there has been various combinatorial interpretations of the sequence. The sequence has been interpreted as the number of preferential arrangements of members of a set with n elements. Alternatively the sequence has been interpreted as the number of ordered partitions; the outcomes in
races in which ties are allowed or geometrically the number of vertices, edges and faces of simplicial objects. An interesting application of the sequence is found in combination locks. The idea of a preferential arrangement has been extended to a wider combinatorial object called barred preferential arrangement with multiple bars. In this thesis we study barred preferential arrangements combinatorially with application to resistance of certain electrical circuits. In the process we derive some results on cyclic properties of the last digit of the number of barred preferential arrangements. An algorithm in python has been developed to find the number of barred preferential arrangements
"Blade is blunt"
No full textOn Wednesday, 21 October 2015, Rhodes University closed in solidarity with the higher education sector as students and staff embarked on nationwide protest action against the shortage of funding in the South African higher education sector. #FeesMustFall is a national student led protest movement that began in mid-October 2015 in response to proposed increases in fees at South African universities. These images depict the peaceful march and illustrate the extent of solidarity among staff, students and community members who joined in support of the protest
"iNzimande lendlela"
No full textOn Wednesday, 21 October 2015, Rhodes University closed in solidarity with the higher education sector as students and staff embarked on nationwide protest action against the shortage of funding in the South African higher education sector. #FeesMustFall is a national student led protest movement that began in mid-October 2015 in response to proposed increases in fees at South African universities. These images depict the peaceful march and illustrate the extent of solidarity among staff, students and community members who joined in support of the protest
"Peace love education"
No full textOn Wednesday, 21 October 2015, Rhodes University closed in solidarity with the higher education sector as students and staff embarked on nationwide protest action against the shortage of funding in the South African higher education sector. #FeesMustFall is a national student led protest movement that began in mid-October 2015 in response to proposed increases in fees at South African universities. These images depict the peaceful march and illustrate the extent of solidarity among staff, students and community members who joined in support of the protest
"SAPS don't hurt any more of our children"
No full textOn Wednesday, 21 October 2015, Rhodes University closed in solidarity with the higher education sector as students and staff embarked on nationwide protest action against the shortage of funding in the South African higher education sector. #FeesMustFall is a national student led protest movement that began in mid-October 2015 in response to proposed increases in fees at South African universities. These images depict the peaceful march and illustrate the extent of solidarity among staff, students and community members who joined in support of the protest
Paparazzi waiting
No full textOn Wednesday, 21 October 2015, Rhodes University closed in solidarity with the higher education sector as students and staff embarked on nationwide protest action against the shortage of funding in the South African higher education sector. #FeesMustFall is a national student led protest movement that began in mid-October 2015 in response to proposed increases in fees at South African universities. These images depict the peaceful march and illustrate the extent of solidarity among staff, students and community members who joined in support of the protest