11613 research outputs found
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Trends in coordination of rhenium organometallic complexes in the Protein Data Bank
No full textRadiopharmaceutical development has similar overall characteristics to any biomedical drug development requiring a compound's stability, aqueous solubility and selectivity to a specific disease site. However, organometallic complexes containing 188/186Re or 99mTc involve a d-block transition-metal radioactive isotope and therefore bring additional factors such as metal oxidation states, isotope purity and half life into play. This topical review is focused on the development of radiopharmaceuticals containing the radioisotopes of rhenium and technetium and, therefore, on the occurrence of these organometallic complexes in protein structures in the Worldwide Protein Data Bank (wwPDB). The purpose of incorporating the group 7 transition metals of rhenium/technetium in the protein and the reasons for study by protein crystallography are described, as certain PDB studies were not aimed at drug development. Technetium is used as a medical diagnostic agent and involves the 99mTc isotope which decays to release gamma radiation, thereby employed for its use in gamma imaging. Due to the periodic relationship among group 7 transition metals, the coordination chemistry of rhenium is similar (but not identical) to that of technetium. The types of reactions the potential model radiopharmaceutical would prefer to partake in, and by extension knowing which proteins and biomolecules the compound would react with in vivo, are needed. Crystallography studies, both small molecule and macromolecular, are a key aspect in understanding chemical coordination. Analyses of bonding modes, coordination to particular residues and crystallization conditions are presented. In our Forward look as a concluding summary of this topical review, the question we ask is: what is the best way for this field to progress?Publisher's versio
An ecocultural exploration of play in young children with developmental delays living in resource-limited contexts: A caregiver perspective
No full textThesis (Ph.D. (Child Psychology))--University of the Free State, 2022Children's play is a natural phenomenon through which children develop and make sense of their world, making play an ideal medium for child-based interventions. While research is available on the play of children with and without developmental delays, minimal research exists on the play of children with developmental delays living in low- and middle-income countries (LMIC). Cross-cultural studies have shown variations in child play, highlighting the importance of contextualised research on the play of children with developmental delays living in culturally diverse, resource-limited settings. This study aimed to explore the play of Basotho children with developmental delays living in resource-limited communities in South Africa from their caregivers' perspective. It explored (a) what they play with (Manuscript 1) and (b) why, how, and where they play (Manuscript 2). Twelve Basotho caregivers of children with developmental delays were purposively selected to participate in two focus groups. The findings revealed ecocultural understandings of access to toys and play materials, specifically the (1) availability, (2) affordability, (3) accessibility, (4) acceptability, and (5) accommodation of play opportunities. Caregivers gave further insight into why their children play (sensory stimulation, emotional regulation, and development), how their children play (the visibility of their disability, specific interests, and play partners), and where they play (at their home). These added to the understanding of play in children with developmental delays living in resource-limited communities. This understanding is imperative for the feasibility of early interventions for children that is also respectful and culturally sensitive to their contexts.Kinderspel (of speel) is 'n natuurlike verskynsel waardeur kinders ontwikkel en sin maak van hul wêreld. Dit maak spel 'n ideale medium vir kindergebaseerde intervensies. Terwyl navorsing beskikbaar is oor die spel van kinders met en sonder ontwikkelingsagterstande, bestaan daar minimale navorsing oor die spel van kinders met ontwikkelingsagterstande wat in lae- en middel-inkomste lande woon. Verder het kruiskulturele studies variasies in kinderspel getoon, wat die belangrikheid beklemtoon van gekontekstualiseerde navorsing oor die spel van kinders met ontwikkelingsagterstande wat in kultureel-diverse, hulpbronbeperkte omgewings leef. Hierdie studie het ten doel gehad om die spel van Basotho-kinders met ontwikkelingsagterstande wat in hulpbronbeperkte gemeenskappe in Suid-Afrika woon vanuit hul versorgers se perspektief te verken. Dit het ondersoek (a) waarmee hulle speel (Manuskrip 1), en (b) hoekom, hoe en waar hulle speel (Manuskrip 2). Twaalf Basotho-versorgers van kinders met ontwikkelingsagterstande is doelbewus gekies om aan twee fokusgroepe deel te neem. Die bevindinge het gelei tot n beter ekokulturele begrip oor die toegang tot speelgoed en speelmateriaal, spesifiek die (1) beskikbaarheid, (2) bekostigbaarheid, (3) toeganklikheid, (4) aanvaarbaarheid en (5) akkommodasie van speelgeleenthede. Versorgers het insig gegee oor hoekom kinders speel (sensoriese stimulasie, emosionele regulering, en ontwikkeling), hoe kinders speel (die sigbaarheid van hul gestremdheid, spesifieke belangstellings, en speelmaats), en waar hulle speel (by hul huis). Sodanige insigte het bygedra tot die begrip van die spel by kinders met ontwikkelingsagterstande wat in hulpbronbeperkte gemeenskappe woon. Hierdie begrip is noodsaaklik vir die uitvoerbaarheid van vroeë intervensies vir kinders wat ook respekvol en kultureel sensitief is vir hul unieke kontekste
Development of a sustainable model for irrigated smallholder agricultural enterprises In Vhembe District, Limpopo Province in South Africa
No full textThesis (Ph.D.(Sustainable Agriculture))--University of the Free State, 2022The purpose of the study was to characterise irrigated smallholder agricultural enterprises led by women and youth (ISHAE-WY) in selected areas of Vhembe District Municipality, Limpopo Province. The characterisation focused on the geophysical environment and on participants in ISHAE-WY. The ISHAE-WY are suffering from a serious loss of traditional farming knowledge, which has been adequately replaced by knowledge of modern farming practices. Diverse agro-climatic zones with distinct seasons can grow a wide range of field crop commodities. It is vital to select crop commodities for cultivation according to the land suitability, so that maximum benefit can be achieved while maintaining ecological sustainability. Indeed, the greatest increases in water use in ISHAE-WY have not been from better irrigation technology or management, but rather from increased crop yields, due to better or efficient application of water to preferred field crops. Selected commodities potential of field crops on ISHAE-WY were evaluated based on the geophysical attributes (e.g., terrain form and soil), and climatic parameter of each type of field crop. This study used a combination of both primary and secondary data acquisition approaches. Long-term environmental and climate data, including topographical data was acquired from the Limpopo Department of Agriculture and Rural Development (LDARD). The data was developed by EnviroGIS as appointed to assist the LDARD in conducting field surveys and analyses to correct the national vector data to a local scale. A representative sample was based on the number of smallholder entrepreneurs per production area within the two identified agro-ecological zones. Primary data was collected using a questionnaire and transect walk (observation). At least 294 women and youth (W-Y) smallholder irrigation entrepreneurs were sampled for interviews and prompt responses were obtained on the influence of productivity and profitability of selected field crops (dry bean, sweet potatoes, and maize) on ISHAE-WY. An average selected mean output of irrigated smallholder agricultural product was determined. The study revealed that there is a great impact of climate on the suitability of the selected field crops in the stuidy area. The potential effects of the high temperatures and low relative humidity are deleterious to the growth and development of young plants. Irrigation during such hot and dry months may not be able to overcome the potential negative effects of the atmospheric evaporative demand, together with high temperature stress on crops grown during this period.
Comparison between informal and formal markets show that the ISHAE-WY who rely on the informal markets are making more profit than with the latter. In selling through the formal market, the market deducts 5% of commission while the market agent deducts 7.5% of sales on the gross value of the sold product. This does not include the transportation charges to the market. The Farm Gate market opportunity seems to be the most predominant approach of marketing at ISHAE-WY. These results reaffirm that ISHAE-WY can also be an alternative employment to W-Y who remain at home, while their counterparts are looking for employment in cities. In the end, the study provides strong motivation that irrigated smallholder agricultural areas has a potential to change the lives of rural households and their local economy
Place, ritual and narrative: a coffee roastery and mushola in the Bo-Kaap
No full textDissertation (M.Arch. (Architecture))--University of the Free State, 2022The Bo-Kaap, previously known as the Cape Malay Quarters, is a vibrant place full of rich history and cultural significance. Tourists flock to the area from all around the world. This has inevitably led to forms of gentrification taking root, and some now see the Bo-Kaap as a kind of exhibition space where the insiders can be viewed by the outsiders. If this continues the Bo-Kaap runs the risk of losing its essence and unique voice within the ever-expanding global society. The possibility of facilitating more dignified interactions between insiders and outsiders needs to be investigated. The proposed design intervention, envisioned as a place born from architectural re-telling, aims to provide a space where insiders and outsiders may find common ground amid overlapping rituals and narratives. In this shared space, a coffee roastery, new empathic connections are encouraged without undermining the established voice of the place, since the proposal also offers a space where the insiders may continue to practice their own sacred rituals. As such, the proposed architectural intervention provides an in-between space for empathetic relationships to be built on the common ground sprouting from overlapping rituals and narratives. The goal is to move from ‘exhibition’ to ‘empathy’ while honouring existing ways of life and being sensitive to the historical urban surroundings
The effect of perceived organizational support and psychological capital on the psychological well-being of teachers
No full textDissertation (M.Com. (Industrial and organizational Psychology))--University of the Free State, 2022Psychological well-being has become of critical importance in the teaching profession for years now. The nature of the working conditions under which teachers must practice their profession contributes to the stressful nature of the profession and the effects of the coronavirus pandemic also contributed. Therefore, the study focused on whether psychological capital and perceived organizational support could enhance psychological well-being of teachers. The primary objective was to determine whether there is an effect of psychological capital and perceived organizational support on the psychological well-being of teachers. The secondary objective was to determine if differences exist in psychological well-being between private and public-school teachers. The study followed a quantitative approach, and the study was based on 204 responses. The respondents were selected based on convenience sampling method and responded to three instruments combined in a self-report questionnaire. Descriptive statistics and inferential statistics were used to analyse the data. Pearson product moment correlation was used to test the correlation between the independent variables and psychological well-being and Stepwise Multiple regression was used to test the predictive value of the variables. The stepwise multiple regression analysis indicated that self-efficacy and optimism contributed 31,9% of the variance in psychological well-being. Overall, the regression model was statistically significant (F=45.250; P<0.001). The Pearson correlation indicated that self-efficacy had a statistically significant correlation with psychological well-being (R=.394, P<0.001). Optimism also had a statistically significant correlation with psychological well-being (R=.383, P<.001). Confirmatory factor analysis was used to test the fit of the sample responses to the original conceptualization of the instruments using goodness-of-fit statistics. The outcomes were that the constructs could not be tested for direct and indirect paths, as the model demonstrated poor fit. The characteristics of the sample and the diversity of the sample did not allow the model to fit. The secondary objective was addressed using independent sample t-test and reported that no significant differences in psychological well-being were found between private and public-school teachers. Conclusions from the study indicated that the combination of personal resources from psychological capital- self efficacy and optimism influences psychological well-being. The Department of Basic Education should look at ways to create and promote a culture that is based on the principles and resources of positive psychology. Future research may focus on unpacking more personal resources that could predict psychological well-being
The enhancement of employee performance through leadership and individual level variables in three Metropolitan municipalities in South Africa
No full textSouth African municipalities are known for poor service delivery, resulting from leaders failing to manage processes and performance. A lack of leadership competencies was cited as one of the reasons for poor employee performance in municipalities. Literature also showed that several individual factors (i.e. employee psychological empowerment, employee workplace spirituality, employee motivation, and employee citizenship behaviour) might play a role in employee performance. However, it is not clear how leadership competencies interact with these individual variables to subsequently influence employee performance. In response to the leadership competency gap and poor performance in the municipalities, the present study sought to address this by developing a leadership competency and employee performance model. In pursuit of this aim, specific objectives were set at the onset: to develop a conceptual leadership competency and employee performance model for municipalities in South Africa, to theoretically explain the relationships between variables in the proposed leadership competency and employee performance model using previous literature, and to determine the predictive validity of the proposed leadership competency and employee performance model in municipalities in South Africa. The Explanatory Sequential Mixed Methods design was selected, applying both quantitative and qualitative methods of data collection and analysis. Municipal employees from the top three municipalities in South Africa (City of Johannesburg Metropolitan Municipality, City of Tshwane Metropolitan Municipality and City of Cape Town Metropolitan Municipality) formed the main body of the population for this research study. A simple random sampling method was used, comprising of municipal employees. Technically, the researcher applied a two-stage sampling approach. Firstly, purposive sampling was used to select the top three municipalities. Secondly, simple random sampling was applied to select the participants from the top three municipalities. For the quantitative part of the study, data was collected from 789 participants that included all office-bound employees, as well as junior to middle management (levels 6 and 7). General workers, technical staff (working on roads, potholes, streetlights etc.) and senior management (levels 1 to 5) were not included. With regard to the quantitative component of the study, six standard questionnaires were used: The Leadership Assessment Questionnaire (LAQ) to assess leadership competencies; The Psychological Empowerment Questionnaire (PEQ) to assess employee psychological empowerment; The Spirituality at Work (SAW) questionnaire to measure employee workplace spirituatliy; The Motivation Measure (MM) questionnaire to measure employee motivation; The Organisational Citizenship Behaviour Scale (OCBS) to measure organizational citizenship behaviour and The Employee Performance Scale (EPS) to measure employee performance. The data was analysed emphasising both descriptive statistics and inferential statistics using SPSS and SmartPLS. The analysis emphasised correlations, stepwise multiple regression and structural equation modelling. For the qualitative component of the research, management holding a position not lower than assistant director (levels 1 to 5), were included. The researcher used purposive sampling to select 15 individuals to be interviewed. These leaders were highly skilled in the municipal field and their input was used as confirmation or to add further knowledge or input into the results of the quantitative findings. Semi-structured interviews were conducted, as the researcher aimed at obtaining specific information to gather more insights or explanations from leaders into quantitative findings. Thematic analysis as a qualitative data analysis technique was applied
Photocatalytic decomposition of an ago dye using transition-metal-doped tungsten and molybdenum carbides
No full textThe preparation, characterization, and photocatalytic application of tungsten or molybdenum carbides (Ni-WC, 1, Co-WC, 2, Ni-MoC, 3, Co-MoC, 4, NiCo-WC, 5, NiCo-MoC, 6, NiFe-WC, 7, and NiFe-MoC, 8) doped with transition metals (Fe, Co, and Ni) are reported. These transition-metal carbide (TMC) particles show that the submicrometer globular particles agglomerated to form larger particles, with smaller crystallites present on the surface of the large particles. These crystallite sizes range between 4 and 34 nm (as calculated from X-ray diffraction data) depending on the metal dopant and type of carbide. Oxidation of the metal carbides is evident from the two sets of photoelectron lines present in the X-ray photoelectron spectroscopy (XPS) of the W 4f area. The Mo 3d spectra reveal four sets of photoelectron lines associated with oxidized MoO2 and MoO3 as well as Mo2+ and Mo3+ associated with MoC1–x. The XPS of the dopant metals Ni, Co, and Fe also show partial oxidation. The photocatalytic decomposition of Congo red (an azo dye) is used as a model reaction to determine the photocatalytic activities of the transition-metal carbides, which is related to the TMCs’ optical band gap energies.Publisher's versio
Social entrepreneurship and community development: The case study of Makwane village, Qwaqwa, Free State
No full textDissertation (MDS (Development Studies))--University of the Free State, 2022Rural communities in South Africa face many challenges that limit their ability to grow
and develop. Among the most significant issues facing communities are
unemployment and poverty (De Beer and Swanepoel, 2016). Despite the numerous
approaches and efforts by government, NGOs, local and international organisation,
achieving community development has been arduous. The high rate of joblessness
and poverty have, impeded social and economic progress. Given the circumstances,
it is vital to develop and carry out creative projects that might offer lasting sustainable
solutions to social problems (Gordon, 2015), there is an urgent need for the design
and implementation of innovative projects that can provide sustainable, long-term
solutions to social problem. Community development is concerned with enhancement in the quality of life and
standard of living of societies. According to Lombard & Strydom (2011), over 60% of
population in South Africa live in rural areas making the country primarily rural. For this
reason, community development initiatives should to be geared towards upgrading the
standard of living of the communities and enabling them to sustain their development.
This understanding helped South African government's focus on the rural
communities. Sadly, despite the community development, efforts have failed to yield
the desired outcome. This status quo as argued by Gordon (2015) has continued to
result in situation in which there is clear mismatch between structures of the
community and the kind of empowerment programmes targeted at them. Social entrepreneurship is a promising method to community development that goes
beyond development assistance. Social Entrepreneurship initiatives are thought to
have the ability to offer, long - term solutions for community development (Lombard
and Strydom, 2011). The concept is one that should be considered as its practice
could contribute positively towards community development in the areas of impact and
sustainability. The primary thrust of this research is to explore social entrepreneurship
as a potential force for community development
Physio-morphological and biochemical traits of dibutyldithiophosphate treated drought-stressed edamame
No full textDissertation (M.Sc.(Botany))--University of the Free State, 2022Edamame (Glycine max L. Merrill) has recently received attention in South Africa due to its high nutritional value. Production of edamame in South Africa is limited since the country consists of arid and semi-arid regions, with insufficient water available for irrigation. Dibutyldithiophosphate, a biodegradable chemical that slowly releases hydrogen sulfide, could be a solution based on recent studies that indicate H₂S acts as a signaling molecule for tolerance induction during various environmental stresses. This study investigated the impact of dibutyldithiophosphate on the physiological, biochemical and morphological characteristics of drought-stressed edamame cultivars (UVE14 and UVE17). Furthermore, the study established the relationships between the physiological, biochemical and the morphological characteristics [plant height, branches per plant, total seeds per plant, total seed mass per plant, and pods per plant] of drought-stressed edamame under different dibutyldithiophosphate concentrations. Dibutyldithiophosphate was directly applied around the seed during sowing before drought stress (30% water holding capacity) introduction at the third trifoliate leaf stage.
Drought stress adversely affected the physiological, biochemical and morphological responses of the edamame cultivars. The efficacy of dibutyldithiophosphate differed according to the cultivars, growth stages (flowering and pod-filling), concentrations of dibutyldithiophosphate (0, 0.1, 1, and 2 mg/mL), as well as the water level (drought or optimal watering). The concentrations required to activate the physiological and biochemical responses were generally higher in drought-stressed UVE17 than UVE14 cultvar. To improve drought tolerance in edamame, dibutyldithiophosphate application upregulated the photosynthetic capacity (increased total chlorophyll content, chlorophyll-a, chlorophyll-b, and photochemical reflective index), which resulted in increased accumulation of sugars (total soluble sugars) and proline. The increase in total soluble sugars and proline indicate that dibutyldithiophosphate application increases the osmotic and antioxidative potential of drought-stressed edamame. Additionally, results of this study showed that dibutyldithiophosphate application decreased membrane damage by increasing the antioxidative capacity [superoxide dismutase, ascorbate peroxidase, flavonoid reflective index, and carotenoid reflective index] in drought-stressed edamame. Application of dibutyldithiophosphate also improved drought tolerance in a susceptible cultivar (UVE17) by increasing pods per plant (0.1 mg/mL), branches per plant (1 mg/mL), and total seed per plant (2 mg/mL). For drought-stressed UVE14, application of dibutyldithiophosphate increased branches per plant (all concentrations), pods per plant (0.1 and 1 mg/mL) and total seed per plant (2 mg/mL). Since there were more positive correlations between the physiological, biochemical and morphological characteristics under 0.1 and 1 mg/mL, these dibutyldithiophosphate concentrations could be recommended for drought tolerance stimulation in edamame. As a result, the hypothesis that application of dibutyldithiophosphate enhances the physiological, biochemical and morphological responses of drought-stressed edamame is accepted. In addition, it is acknowledged that application of dibutyldithiophosphate on drought-stressed edamame increases the relationships between physiological, biochemical and morphological responses
Blue Rock Extreme Sport Eco Institute for the Western Cape, Sir Lowry's pass
No full textDissertation (M.Arch. (Architecture))--University of the Free State, 2022This dissertation was born through my fascination with the industrial archetype and the growing popularity thereof all over the world. The proposed project handles the growing popularity of extreme sport in South Africa and how a space can be created for those seeking a rush of adrenalin. By addressing the need for a natural environment where individual is allowed to break away from their daily routine, the Blue Rock Extreme Sports Institute assists in providing relief from the growing mental and physical health issues we are faced with. The dissertation handles the opportunities for ecological and architectural development within a quarry, allowing the user to witness the beauty of the historical mining industry and not only see it as wasted space. Through the novel use of the scarred environment and manmade contours, the memory of industrial history will come back to life within the quarry. The levels and slopes left behind within the quarry walls will be used as a way of passage to the waters below through promenades, allowing all users to interact with one another. Researching the different tensile forces used in the mining industry and observing the materials used I was able to develop a conceptual image of what could be possible within the given environment. The impact of the research done could hopefully open people's eyes to the endless architectural opportunities we are faced with, especially in the scars left behind from the distant and recent past