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Defining the frontiers of synergism between cellulolytic enzymes for improved hydrolysis of lignocellulosic feedstocks
No full textLignocellulose has economic potential as a bio-resource for the production of value-added products (VAPs) and biofuels. The commercialization of biofuels and VAPs requires efficient enzyme cocktail activities that can lower their costs. However, the basis of the synergism between enzymes that compose cellulolytic enzyme cocktails for depolymerizing lignocellulose is not understood. This review aims to address the degree of synergism (DS) thresholds between the cellulolytic enzymes and how this can be used in the formulation of effective cellulolytic enzyme cocktails. DS is a powerful tool that distinguishes between enzymes’ synergism and anti-synergism during the hydrolysis of biomass. It has been established that cellulases, or cellulases and lytic polysaccharide monooxygenases (LPMOs), always synergize during cellulose hydrolysis. However, recent evidence suggests that this is not always the case, as synergism depends on the specific mechanism of action of each enzyme in the combination. Additionally, expansins, nonenzymatic proteins responsible for loosening cell wall fibers, seem to also synergize with cellulases during biomass depolymerization. This review highlighted the following four key factors linked to DS: (1) a DS threshold at which the enzymes synergize and produce a higher product yield than their theoretical sum, (2) a DS threshold at which the enzymes display synergism, but not a higher product yield, (3) a DS threshold at which enzymes do not synergize, and (4) a DS threshold that displays anti-synergy. This review
deconvolutes the DS concept for cellulolytic enzymes, to postulate an experimental design approach for achieving higher synergism and cellulose conversion yields.Publisher's versio
'With divided mind and unsure steps': South Africa from referendum to republic, August 1960 May 1961
No full textIn October 1960 the South African government held a Whites-only referendum on whether South Africa should become a republic. The establishment of the republic is often seen as the 'last battle of the Boer War' and therefore interpreted as a political matter with Afrikaners in opposition to English-speaking South Africans. The referendum question did not solely affect South Africa's constitutional structure. Numerous voters and politicians were concerned that South Africa would be excluded from the Commonwealth and would become increasingly isolated due to the apartheid policy upon becoming a republic. After gaining a narrow majority in favour of a republic, the government withdrew South Africa from the Commonwealth in March 1961 and proceeded with the establishment of the republic in May of that same year. Despite the 52% vs 48% outcome of the referendum, the period is often seen as a period of increasing unity between white political groupings. The lack of opposition from white citizens to this process is frequently interpreted as a sign of increased support for the National Party. This thesis explores the events and motivations from the referendum to the republic as a complex political issue by examining public opinion and voter motivation. The primary sources used in this thesis are editorials and readers' letters published in mainstream newspapers. Readers' letters and editorials were examined at three intervals: during the referendum campaigns, in reaction to the withdrawal from the Commonwealth, and at the establishment of a republic which coincided with anti-apartheid demonstrations. These opinions were analysed qualitatively and quantitatively in conjunction with archival source material. This thesis utilises an in-depth analysis of white public opinion to explore the factors that politically motivated the white electorate in their acceptance or rejection of a republic. The thesis argues that the economy and racial politics were decisive factors in determining the outcome of the referendum and the reactions to the events that followed. The establishment of the republic is often seen as part of the National Party's road to political domination and as being driven by white cultural-political divisions. Close analysis of public opinion highlights how this process was, however, one of 'divided mind and unsure step' for numerous members of the white electorate
Exploring association between self-reported financial status and economic preferences using experimental data
No full textResearch on economic behaviour of individuals in different financial statuses such as being in a good financial standing or in a threatening financial situation are inconclusive. Some evidence suggest that the culture of poverty may shape and dominate the economic preferences of those who are poor and even make them being prone to trembling and making mistakes thereby making decisions that do not maximize their utility. Other evidence suggest that the poor exercise extra caution and fail to maximize utility. This study investigates the association between self-reported financial status and economic preferences in a developing country setting using data from an incentivized experiment and a survey. Extended random effects panel probit regression models are employed as an analytical strategy. The study established a positive association between being financially broke or very broke and being risk averse. In addition, a positive association is found between being financially ‘very broke’ and impatient. Such findings illustrate the importance of psychology of poverty in economic preferences and in decision-making in general, even as poverty is temporary as represented by self-reported financial status.Publisher's versio
Diagnostic accuracy of ultrasound-guided fine needle aspiration cytology of thyroid nodules at Universitas Academic Hospital, Bloemfontein
No full textBackground: Fine Needle Aspiration Cytology (FNAC), is safe, reliable and minimally invasive first-line investigation used to evaluate thyroid nodules. Aim: To determine the diagnostic accuracy of FNAC performed at our institution by correlating its results with histopathological diagnoses. Methods: A retrospective analysis was conducted of cytology and histopathology results of patients who underwent both FNAC and thyroidectomy at Universitas Hospital, Bloemfontein, over a 5-year period (2014–2018). Cytological findings were classified into six Bethesda categories while histological results were categorised as benign or malignant. Adult patients (≥ 18 years) who underwent both thyroidectomy and FNAC for nodular thyroid disease were included. Results: Sixty-one cases fulfilled the inclusion criteria. On cytological examination, 28/61 (45.9%) were reported as benign, 11/61(18.0%) as malignant and 10/61(16.4%) as suspicious. On histopathological reports, 29 cases were confirmed as benign and 10 as malignant. Among 10 suspicious cases, four were malignant on histopathology. False positive and false negative rates were 15.3% and 12.8%, respectively. The sensitivity and specificity were 50.0% and 79.3%, respectively. The positive and negative predictive values were 45.5% and 82.1%, respectively. The diagnostic accuracy of FNAC was 71.8%. Conclusions: FNAC at our institution has not performed as good as most similar studies published previously
The prevalence of bleeding disorders in women with regular heavy menstrual bleeding at a secondary gynaecology clinic in central South Africa
No full textBackground: Heavy menstrual bleeding (HMB) affects 10-15% of women. Studies from developed countries show that 20% of females with heavy menstrual bleeding have an underlying bleeding disorder. The prevalence of bleeding disorders in patients with HMB has not been determined in South Africa. Objectives: To determine the prevalence of bleeding disorders in women with heavy menstrual bleeding in a tertiary gynaecology clinic in central South Africa and to evaluate the use of the Molecular and Clinical Markers for the Diagnosis and Management of Type 1 VWD bleeding assessment tool (MCMDM-1 VWD BAT) and the bleeding time in identifying women with HMB with underlying bleeding disorders. Methods: This was a prospective descriptive study. Forty-one patients with heavy menstrual bleeding not attributable to other causes in the PALM-COEIN classification were recruited. Demographic data were collected, the MCMDM-1 VWD BAT was administered, a modified Ivy bleeding time was done, and routine laboratory testing was done to exclude non-haematological conditions. Screening tests for coagulation disorders were done. Results: Forty-one patients were recruited for the study, but only 36 had a complete data set. None of the patients were identified to have an underlying bleeding disorder even though seven patients (19.4%) had an elevated MCMDM-1 VWD score, despite the lack of laboratory evidence of a bleeding disorder. One (2.5%) patient had an elevated bleeding time. All the patients were referred from primary healthcare clinics. Conclusion: The prevalence of bleeding disorders in this study is low when compared to studies done elsewhere, even though there was selection bias. Half of the patients were already on contraceptives, which might have reduced their bleeding symptoms. Our functional Von Willebrand factor assays were dependent on ristocetin and may have overestimated the Von Willebrand factor concentration. The MCMDM-1 VWD bleeding assessment tool was easy to administer. The bleeding time did not contribute to the diagnosis. The study needs to be repeated in a primary care setting, using Von Willebrand factor assays that are independent of ristocetin. Such studies are indicated to determine to true prevalence of bleeding disorders in patients with heavy menstrual bleeding in South Africa
Missio Dei as the main project: project management model for mission of God
No full textThe emergence of the concept of Missio Dei (Mission of God) from the perspective of the International Missionary Council (IMC) arguably demonstrated that the role of the Triune God in his own mission was undeservedly marginalized for decades, if not centuries preceding 1952. Over the past decades there has been a sustained research activity conceptualizing Missio Dei, and at the same time renewing missiological interest in other Christian missions. However, to the author’s awareness, there has been very little or no effort to introduce or use known project models that can be utilized to show coherence or collaboration of missions towards the project of fulfilling the objective of Missio Dei. Through a desk-top literature review, this paper proposes the use of a project management model to properly conceptualize the location of Missio Dei as a main project that includes other network of missions as sub-projects within its framework. The Triune God is here identified as Project managers while human participants are seen as project stakeholders. Christian missions include Missio Christos, Missio Spiritus, Missio Hominum and Missio Ecclesiae as sub-projects. The proposed model will demonstrate the coordination and collaboration of missions in the broader context of Missio Dei and further assist with a proper understanding of roles that each mission is, or should play, in achieving the objective of Missio Dei. While efforts are being made here to propose a project management model for Missio Dei, further research is needed to determine whether this proposal will yield an in-depth understanding of Missio Dei as a missiological paradigm in conjunction with the role of other missions.Publisher's versio
Learning needs of caregivers of older persons in residential care facilities: an explorative case study
No full textCaregivers play a prominent role in rendering basic care to older persons in residential care facilities, whose needs are intricate and unpredictable. Yet, caregivers were found to be underprepared, especially in rural areas of the Northern Cape province in South Africa. Substandard education, training and the absence of formal in-service training programmes contribute to varied quality of care, as well as caregiver stress and burnout. Therefore the question arose: What are the learning needs of caregivers of older persons in residential care facilities in two sub-districts of the Northern Cape province? Guided by constructivism, knowledge was socially constructed by incorporating the perspectives of various role players. In accordance with the research question and the need to obtain multiple perspectives within a particular geographical context, an explorative case study design was applied. Data were collected by means of four respective nominal groups with caregivers and family members of residents, as well as a small group interview with the registered nurses working at three facilities. During data analysis the different data sets were individually analysed and then consolidated. Eight main categories of learning needs were identified, namely: basic nursing skills, hygiene, Alzheimer’s disease, medication, communication, rights and responsibilities, as well as staff monitoring and evaluation. Many of the suggested learning needs were, however, beyond the expected tasks of caregivers set by the South African Qualifications Authority unit standard for the provision of care to a frail person. The ignorance of the caregivers with regard to essential aspects such as their rights and job description revealed unfair labour practices. Ethics of employment emerged from the findings as underlying theme with unrealistic work expectations and a power disadvantage as subthemes. A formal in-service training programme addressing the learning needs, appropriate for the caregivers’ expected level of functioning could enrich the quality of their caring for older persons in the particular residential care facilities. Action should also be taken to address the emerging issues affecting both the caregivers and quality of care rendered to older persons in this setting. Further, larger scale research could cast light on the research issue in other contexts and ostensibly inform policy development in this regard
Enhancing the teaching and learning of algebraic expressions and equations through reasoning in Grade 9
No full textThesis (Ph.D.(Curriculum Studies))--University of the Free State, 2021This study sought to enhance the teaching and learning of algebraic expressions and equations using reasoning in grade 9. It is a participatory action research study underpinned by bricolage paradigm and construction theory. The underpinnings guide and enable learners to use what is at their disposal to construct reasoning constructs. The constructs help learners to forge rich algebraic and mathematical conceptual connections and interrelations. In this manner, the constructs help the instruction (teaching and learning) to achieve deep conceptual understanding (DBE 2011:8) rather than limiting it to procedural orientation. The evidence presented in literature about international best practices shows that procedure-oriented instruction and procedure fluency are, and should be, nested in conceptual knowledge. This study initiated the instruction that ensures that the nesting does not manifest in nature only, but throughout the teaching and learning processes as well. The initiative draws from the South African curriculum policy, CAPS, which requires that learners should achieve a deep conceptual understanding of the subject matter (DBE 2011:8).
The operationalisation of reasoning to conceptualise procedural instruction draws from the underutilisation of the reasoning skill, despite it being the curriculum policy imperative. Reasoning attaches sensible meaning (Yackel 2001:1) to algebraic content matter and provides direction and cushion for logical arguments aimed at attaining high order cognition. Pursuant to the study underpinnings, the reasoning-based instruction deploys learners’ own reasoning constructs to ensure participatory and contextual conceptualisation. In the process, learners develop critical thinking and high order cognitive skills. These are the skills that the learners are expected to attain from the meaningful learning (Pramesti & Retnawati 2019:3) of algebra and mathematics inspired in the reasoning-based instruction.
The study has come up with the components of solution and strategies to address the research question and challenges underlying the research. The primary challenge that guides the study, namely the non-alignment between the instruction and requirements of the curriculum policy, manifests under procedure-oriented instruction; assessment; teachers’ competences and curriculum-time contestation. In addition, the abstraction and complexity of algebra amidst insufficient basic mathematics competency, escalate the supremacy of algebra in the teaching and learning of mathematics. The net resultant thereto is an inherent sifting nature of algebra.
The data analysis and interpretation presented enough evidence that the reasoning-based instruction is couched in multi-layered components of solution and strategies that respond adequately to the research question. The instruction proved the potential to break through the integrated challenges underlying algebraic instruction. The process of conceptualisation is an encompassing component of the solution. It entails contextualising and concretising textual representations of algebra in a manner that the representations make meaningful sense to learners; so much that the learners can apply algebra purposefully in advanced mathematics and related learning. Contextualisation often involves refocusing, integration and re-organisation of content matter in a manner that meets the subject and learners’ needs. Concretisation includes the use of materials and examples within learners’ reach to explain algebraic concepts.
The analysis of the conditions necessary for successful implementation and that of the risks and threats likely to impede the implementation reaffirmed the sustainability of the reasoning-based instruction. The indicators of success confirmed that the study has succeeded in the reform, transformation and enhancement of the teaching and learning of algebra as sought and anticipated. The study has further empowered co-researchers to use what is at their disposal to develop sustainable solutions. It can then be concluded that the research empowered the initiatives to overcome the ‘lock-ins’ to existing protocols and approaches, which have not been effective for the majority of teachers’ and learners’ populations in South Africa and the world.
___________________________________________________________________Hierdie studie mik daarop om 'n strategie te ontwerp om die onderrig en leerproses van algebraïese uitdrukkings en vergelykings in graad 9 te verbeter. Dir towrdsommer ook deur gebruik te maak van die redenasieproses. Dit is 'n deelnemende proses wat ondersteun word deur die opbou van die redenasieproses as bricoleur; gemik op ‘n beter begrip; eerder as om dit tot prosedurele beginsels te beperk. Die stawende literatuur oor internasionale beste praktyke, toon dat prosedureel-georiënteerde onderrig en die vloeibaarheid van prosedures gabasseer moet word in konseptuele kennis.
Die gebruik van redenasies om prosedurele instruksies te konseptualiseer, spruit uit die onderbenutting daarvan, alhoewel dit 'n noodsaaklike vaardigheid is waarvoor die kurrikulumbeleid, CAPS, voorsiening maak. Daar is gevind dat die redenasieproses sinvolle betekenis aan algebraïese inhoud heg en rigting en ondersteuning bied vir logiese argumente, wat op hul beurt daarop gemik is om hoër kognisie te bereik. Ingevolge die grondvlak van hierdie studie, gebruik die strategie leerders hul eie redenasievermoëns om deelnemende en kontekstuele konseptualisering te verseker. In hierdie proses ontwikkel leerders kritiese denke en hoër-orde kognitiewe vaardighede, wat nodig is vir die betekenisvolle begrip van algebra.
Die studie het met strategieë en oplossings vorendag gekom om die navorsingsvraag en die uitdagings onderligend daaraan aan te spreek. Die primêre uitdaging van die studie, naamlik die ontwrigting tussen die opdrag en vereistes van die beleid, manifesteer onder prosedure-georiënteerde onderrig, assessering, die vaardighede van onderwysers en die stryd vir kurrikulumtyd. Daarbenewens verhoog die abstraksie en kompleksiteit van algebra, te midde van onvoldoende vaardighede in basiese wiskunde, die belangrikheid van algebra in die onderrig en leer van wiskunde, en word die inherente siftigsaard daarvan blootgelê.
Die navorsingsanalise en -interpretasie het genoegsame bewyse gelewer dat die redenasie-gebaseerde strategie gevestig is in strategieë en oplossings met veelvuldige lae wat voldoende reageer het op die navorsingsvraag, en die potensiaal het om die kontekstueel geïntegreerde uitdagings van hierdie studie te staaf. Die konseptualiseringsproses is 'n omvattende komponent van die oplossing. Dit behels om die kontekstualisering en konkretisering van die teksvoorstellings van algebra op 'n manier sinvol te maak vir leerders; in so ‘n mate dat leerders dit kan toepas in verwante vakrigtings soos tydens die navorsingsproses. Kontekstualisering behels dikwels die herfokus, integrasie en herorganisasie van inhoud op 'n manier wat voldoen aan die behoeftes van die leerders. Konkretisering behels die gebruik van items en voorbeelde binne leerders se bereik om algebraïese konsepte te verklaar.
Die analise van die voorwaardes wat benodig word vir suksesvolle implementering, en die risiko's wat die implementering kan belemer, het die volhoubaarheid van die strategie bevestig. Die sukses het bevestig dat die studie daarin geslaag het om die onderrig- en leerproses van algebra te hervorm, te transformeer en te verbeter soos verwag is. Die studie het mede-navorsers verder bemagtig om dit wat tot hul beskikking is, te gebruik om volhoubare oplossings te ontwikkel. Daar kan dan tot die gevolgtrekking gekom word dat die navorsing die inisiatiewe bemagtig het om die houvas van bestaande protokolle en benaderings te oorkom, wat nie effektief was vir die meerderheid van die onderwysers en leerders in Suid-Afrika en die wêreld nie.
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Critical analysis of rheumatic mitral valve surgery outcomes in central South Africa
No full textDissertation (M.Med.(Cardiothoracic Surgery))--University of the Free State, 2021Introduction: Rheumatic heart disease (RHD) is still an important cause of acquired heart disease affecting children and young adults from poor socio-economic backgrounds. The most common presentation of RHD is mitral valve disease requiring surgical intervention. The study aim was firstly to describe peri-operative risk factors, procedures performed and surgical outcomes after mitral valve surgery for RHD in Central South Africa. Secondly, to compare these results in patients presenting with mitral regurgitation to those presenting with mitral stenosis and mixed mitral valve disease. Methods: Patients undergoing mitral valve surgery for RHD, with or without concomitant tricuspid valve repair between January 2009 and December 2019 were identified from the departmental database. The lesions were grouped into mitral stenosis (MS), mitral regurgitation (MR), and mixed mitral (MX) disease. Statistical analyses was performed using the IBM SPSS program, version 26.0. A p-value of 0.05 or less was considered statistically significant. Results: A total of 242 patients were included in the study of which 75.2% (n=182) were female. Black patients represented 74.4% (n=180), whites 13.6% (n=33) with Asian and mixed races at 12% (n=29). The mean age of the study population was 43.7 years. Distribution of patients according to the lesions was 25.6% (n=62) for MS, 45.0% (n=109) for MR and 29.3% (n=71) for MX disease. Patients presenting in NYHA status III and IV formed 44% of the MR group and 44% of the MS group and for 28% for the MX group. Calculated EuroSCORE > 5 was 29.4% (n=18) in the MS group, 29% (n=32) in the MR group, and 9.9% (n=7) in the MR group. For the MS group, 96.7% (n=60) had mitral valve replacement and only 2.8% (n=2) were repaired (valvotomy); whilst in the MR and MX groups the replacement vs repair rate was 90.3% (n=93) and 94% (n=63) vs 9.7% (n=10) and 5.6% (n=4) respectively. The MS group had the highest number of concomitant tricuspid valve repair at 58.0% (n=36) as compared to MR (38.5%) and MX (35.2%) groups. There was no statistical difference across the groups with regards to the post-operative stroke rate (1%) as well as the rate of in-hospital complications (14%). In-hospital mortality for the entire cohort was 3.8% (n=9), with 4.8% (n=3) for the MS, 3.7% (n=4) in the MR group and 2.8% (n=2) in the MX group. Of the 242 patients in the study 82 did not have their follow up at the UAH clinic. For the 160 patients followed up at UAH clinic, the median follow-up time was 2.68 years, with 35 patients having had follow-up visits > 5 years. Conclusion: Patients received mitral valve surgery had RHD and were young females from poor socio-economic backgrounds with an average age in the 4th decade of life. MR was the most common lesion with replacement being the most performed operation in our unit. The post-operative complications rate as well as the in-hospital mortality were comparable to the published literature
The impact of electronic devices during the Covid-19 pandemic on Grade 2 learners' socio-cognitive development
No full textDissertation (M.Ed.(Early Childhood Care and Education))--University of the Free State, 2021The COVID-19 pandemic has led to an increased usage of electronic devices by learners, due to virtual classrooms and devices used for entertainment, which may impact the socio-cognitive development of learners. Previous studies done mainly outside of South Africa show mixed results: Electronic devices are beneficial to a certain extent but have detrimental effects on learners' social behaviour and cognitive abilities. The impact of electronic devices on the socio-cognitive development of learners has not yet received adequate attention from researchers within South Africa. This study aims to explore the impact of electronic devices during COVID-19 on the socio-cognitive development of Grade 2 learners. The location of the research is in a preparatory school (Grades 1 to 3) in the Eastern Cape province, South Africa. The quantitative research design used three questionnaires (screen time, social development, and cognitive development) participated in by parents, teachers and learners respectively, framed by Bandura's Social Cognitive Theory. The findings of the study showed that online learning and school closures severely impacted the socio-cognitive development of learners, and that they were not at the expected developmental level for their age group. Screen time increased significantly. However, the different levels of electronic device usage by learners had no significant impact on development. The COVID-19 pandemic, school closures, and online learning had a detrimental effect on the socio-cognitive development of the learners. Intervention should be done to address the underdeveloped socio-cognitive skills of learners