Mental Health Consequences of Unemployment: Mental Health, Somatic Symptoms, Depressive Affect and Positive Affect

In this dissertation, we endeavoured to investigate the relationship between mental health and labour market changes in South Africa. We started by understanding the relationship between the aggregate CESD-10 and labour market status and then explored whether this aggregate relationship holds true for each of the three mental health factors that make up the CESD-10 score. Using data from the National Income Dynamics Study, waves 1-5, we documented increasing mental health symptoms with employed to other states of unemployment. This follows for somatic symptoms, depressed affect and positive affect, but the source driving the effects differs between factors and with the CESD-10 as well. We found that those who are NEA suffer to a greater extent in positive affect than in the other two factors relative to the employed. For those who are unemployed (discouraged), we see they also experience the strongest detrimental effect to their positive affect relative to the employed. However, they experience lower depressed affect scores relative to the employed. Those who are unemployed (strict), meanwhile, experience greater depressed affect scores out of the three factors when compared to the employed. As such, we expect to see an average increase in depressive symptoms classifications among those moving from employed to NEA statuses. We can also expect an average increase in depressed affect disorder classifications among those moving from employed to NEA labour force status. Likewise, we can expect higher positive affect across the five waves among those moving from a employed to NEA status. We find that, after controlling for observed individual characteristics and utilizing the panel structure of the data by allowing for individual specific fixed effects, negative labour market shifts have a significant negative impact on mental health. The sub-group analysis shows that this has a particularly adverse effect on black people and males

Diversity and industrial potential of hydrolaseproducing halophilic/halotolerant eubacteria

Halophilic and haloterant eubacteria have been isolated from different marine and hypersaline environments. Halophilic eubacteria also occur in environments typified by more than one soda lakes which are both hypersaline and extremely alkaline. These organisms have been shown to produce a wide array of hydrolytic enzymes including proteases, amylases, xylanases, cellulases as well as lipases and DNases. These enzymes are commonly applied in the production of fermented food and food supplements, in animal feed, laundry detergents and textile industries. Several studies have shown that enzymes derived from halophilic and halotolerant eubacteria are not only halostable but may also be thermostable and alkalistable. This extremophilicity make the enzymes suitable candidates in various fields of biotechnology and may even open up new application opportunities

The Diversity and Dynamics of Indigenous Yeast Communities in Grape Must from Vineyards Employing Different Agronomic Practices and their Influence on Wine Fermentation

The current study evaluated the diversity of yeast species in Cabernet Sauvignon grape must derived from three neighbouring vineyards from a similar terroir but on which significantly different management practices are employed. The fermentation kinetics and yeast population dynamics were monitored from the beginning to the end of spontaneous fermentation. The grape musts were characterised by distinct yeast populations comprising oxidative, weakly fermentative and strongly fermentative yeasts. Different combinations of dominant non-Saccharomyces yeasts were observed in each must, with significantly different assortments of dominant species, including Starmerella bacillaris (synonym Candida zemplinina), Lachancea thermotolerans, Hanseniaspora uvarum, Candida parapsilosis and Wickerhamomyces anomalus. None of these yeast consortia appeared to affect the growth of Saccharomyces cerevisiae or inhibit the overall progress of fermentation. However, the percentage of fermentative yeasts was positively correlated with the fermentation rate. Glucose and fructose consumption rates suggested active participation of both glucophilic and fructophilic yeasts from the onset of fermentation. The data highlight two parameters, viz. initial cell concentration and yeast community composition, as important fermentation drivers and open the possibility to predict fermentation behaviour based on the initial composition of the yeast community

Isolation of hydrolase producing bacteria from Sua pan solar salterns and the production of endo-1, 4-bxylanase from a newly isolated haloalkaliphilic Nesterenkonia sp.

Eighty seven bacterial isolates were obtained from evaporator ponds using culture enrichment technique and screened for xylanase, mannanase and cellulase activity. Based on biochemical and phenotypic characteristics, the isolates were divided into 18 groups. Thirteen groups were Bacillusspecies, four were Halomonas species, while one group belonged to the genus Nesterenkonia. Four Bacillus isolates, Sua-BAC005, Sua-BAC012, Sua-BAC017 and Sua-BAC019, as well as Nesterenkonia sp. Sua-BAC020 were studied further. Isolate Sua-BAC005 affiliated with Bacillus amyloliquefaciens secreted 12.6 U/ml and 9.0 U/ml b-mannanase and b-xylanase, respectively, while isolates Sua-BAC012, Sua-BAC017 and Sua-BAC019 affiliated with Bacillus licheniformis, produced less than 2 U/ml of xylanase, cellulase and mannanase. Nesterenkonia sp. Sua-BAC020 grew at 0 – 20% NaCl with anoptimum at 2.5% NaCl, and at pH 7 – 9.5 with an optimum at pH 9. This isolate produced 3.5 U/ml xylanase when cultivated at pH 8 in 10% NaCl. Five xylanase activity bands were detected on Native-PAGE coupled with zymogram

Determining the level of condom use and associated factors among married people in Tshwane District of South Africa

Introduction: despite the wide availability of free male condoms in South Africa, high rates of new HIV transmissions are reported to occur among married couples. The aim of this study was to determine the level of condom use among the married people and to assess the factors associated with condom use in the Tshwane district of the Gauteng province. Methods: a cross-sectional study was conducted among 325 clients accessing health care services at the Steve Biko Academic Hospital. A self- administered questionnaire was used to collect data, which were entered onto an Excel spreadsheet and imported into Epi info version 7 for analysis. A logistic regression model was used to investigate the association between condom use and the explanatory variables. The odds ratio was used to measure the strength of the associations. The 95% CI and a cut-off point of 0.05 for the p-value were used to indicate statistical significance. Results: the mean age of the participants was 41.6 years (SD=7.7). Two hundred and seventy-six (276; 85%) of the 325 participants reported not using condoms. Trust, doing regular HIV testing, and refusal by the husband were among the reasons given for not using condoms. In this study it was found that, the level of education, age and employment status were the determinants of condom use. Conclusion: the level of condom use was low and sero-discordance was found to be the primary motivator for condom use. This study recommends the strengthening of and the widespread implementation of the CVCT service

Non-Saccharomyces Killer Toxins: Possible Biocontrol Agents Against Brettanomyces in Wine?

Red wine spoiled by the yeast Brettanomyces bruxellensis is characterised by off-odours commonlydescribed as horse sweat, phenolic, varnish and band-aid. The growth of this yeast in wine is traditionallycontrolled by the use of sulphur dioxide (SO2). However, the concentration of SO2, the pH of the wine,the presence of SO2-binding chemical compounds in the wine, as well as the strain of B. bruxellensis,determine the effectiveness of SO2. Other chemical preservatives have been tested, but are not much moreefficient than SO2, and methods used to clean barrels are only partially effective. Filtration of wine andthe use of electric currents/fields are also reported to alter the physical and sensory properties of wine. Inthis context, alternative methods are currently sought to achieve full control of this yeast in wine. Killertoxins have recently been proposed to fulfil this purpose. They are antimicrobial compounds secretedby Saccharomyces and non-Saccharomyces yeasts, displaying killer activity against other yeasts andfilamentous fungi. They are believed to play a role in yeast population dynamics, and this killer phenotypepotentially could be exploited to inhibit the growth of undesired microorganisms within a microbialecosystem such as that occurring in wine. In this review, non-Saccharomyces killer toxins are describedand their potential application in inhibiting B. bruxellensis in wine is discussed in comparison to othertried methods and techniques

A Shotgun Metagenomic Sequencing Exploration of Cabernet Sauvignon Grape Must Reveals Yeast Hydrolytic Enzymes

Shotgun sequencing was employed to explore the community structure (phylotyping of rRNA genes) andfunctional potential of Cabernet Sauvignon grape must microbiome. A metagenomic library, representing92.6 Mb of genetic information, was generated from DNA obtained from Cabernet Sauvignon grapemust.. Fungi were identified as the dominant domain (59.5%) followed by Streptophyta (39%). Amongthe 84 fungal species, 22 were yeasts of various genera. Additionally, grapevine endophytes such asDavidiella sp., Botryotinia fuckeliana, Alternaria sp., and Cladosporium sp. were identified. An unusuallyhigh prevalence of Mucor spp. was evidenced. Functional annotation revealed sequences of genesinvolved in metabolism (35.6%), followed by poorly characterized categories (28.3%), cellular processesand signalling (18.4%), and finally information storage (17.8%). Among the former, glycosidases wereabundant followed by glycogen debranching enzyme, 6-phosphofructokinase and trehalose-6-phosphatesynthase. Furthermore, the taxonomic analysis of the functional sequence data exhibited the eukaryoticgene pool that predominantly contains sequences derived from Streptophyta (mainly Vitis vinifera) 60% >Ascomycota (32%) > Basidiomycota (5%) > Bacteria (2.5%). Finally, sequences of a variety of hydrolyticenzymes of potential oenological relevance were retrieved, thereby confirming that grape juice is a richreservoir for valuable biocatalysts that should be explored further

The potential roles of interactions between STAT3, Hsp90, and Hop in the maintenance of self-renewal in mouse embryonic stem cells

Self-renewal of mouse embryonic stem (mES) cells is dependent upon the presence of leukemia inhibitory factor (LIF). LIF induces tyrosine phosphorylation and nuclear translocation of STAT3 (signal transducer and activator of transcription 3) which is thought to promote self-renewal by inducing key target genes. The molecular chaperone heat shock protein 90 (Hsp90) is involved in signal transduction pathways and regulates STAT3 activity in different cell types. However, the role of Hsp90 in regulating STAT3 activity in mES cells has not previously been investigated. The aim of this study was to investigate if Hsp90 interacts with STAT3 in mES cells and to determine if this interaction is important for the maintenance of self-renewal. It was found that when mES cells were cultured for 24.0 hours in the absence of LIF, the expression levels of total STAT3, tyrosine-phosphorylated STAT3 (pYSTAT3), and the pluripotency marker, Nanog, were down regulated. However, the expression level of Hsp90 was found to be slightly up-regulated over the same period. Significantly, it was found that the amount of STAT3 in differentiating mES cells available for binding to Hsp90 was decreased upon down-regulation of STAT3 by LIF withdrawal. Therefore, STAT3-Hsp90 interactions in mES cells were dependent on the presence of LIF, which suggested that the reduction in STAT3-Hsp90 interaction may have resulted from the low levels of STAT3. Despite a dramatic reduction in the expression levels of pYSTAT3 upon 24.0 hours of culture of mES cells in the presence of the STAT3 tyrosine phosphorylation inhibitor, cucurbitanin I, there was no obvious reduction in the levels of total STAT3, Oct-3/4 or Nanog. These results suggested that the levels of unphosphorylated STAT3 rather than pYSTAT3, maybe more important in the maintenance of mES cells self-renewal

English as a language of learning and teaching science in rural secondary schools : a study of the Vlakfontein circuit in Limpopo

The growing diversity of school populations around the world means that for many learners the language of learning in mainstream classrooms is not their first language. The researcher would submit that content-based second language learning in a context such as a Science classroom is considered advantageous as it enables the learner to manipulate a target language such as English in a way which is meaningful. However, Science learners who have yet to achieve communicative competence in English are disadvantaged when it comes to developing a deep understanding of scientific concepts. Many mainstream Science educators have concerns about this significant group of learners who can be left on the periphery of the class to cope as best as they can. Very often educators aim to meet the needs of English Second Language (ESL) learners without any specific knowledge of the strategies which would enhance learning and ensure that learning environments encourage participation and interaction. The learners themselves have not only to deal with language and sociocultural issues but must face the cognitive demands of Science including negotiating its specialized language. The aim of this study was to investigate how the use of English as a language of learning and teaching Science in rural secondary schools in the Vlakfontein Circuit of the Limpopo Capricorn District, influenced the ability of Grade 8 students to learn Science. The focus was on the Grade 8 classes since they are at the threshold of their educational pursuit. The study had two main purposes. The first goal was to describe the current situation with respect to rural secondary school learners and their educators in selected learning environments in Vlakfontein Circuit. The second goal was to bring about improvement in the learners’ situations by employing specifically designed interventions. The study had three focal areas: the language; the teaching and learning environment; and the ESL learner. The investigation was conducted in disadvantaged rural secondary schools in the Vlakfontein Circuit in the Limpopo province. Observations of the Science classes revealed that, even for the learners with very limited English language proficiency there was little ESL specialist support available. The data analyzed was collected using a variety of data collection tools. The main data generation tools were observation, semi-structured interviews and questionnaires. The analysis revealed that learners were lacking in Science register (terminology). This study also found out that non-technical language used in Science lessons affected the learners’ understanding much more than the educators were aware. Educators’ attitudes and beliefs strongly influenced the interaction and participation of ESL learners in Science classrooms. The study also revealed that developing language skills prevented ESL learners from asking questions and answering questions in class and academic progress in Science was impeded by limited opportunities for ESL learners to clarify their understanding. Further, the investigation established that achievement in Science and in education overall was affected by assessment instruments which were infused with specific linguistic or cultural knowledge. The study arrived at a conclusion that the needs of the research students could not be met by a programme based on the traditional format of ESP teaching. Hence, the researcher has recommended a Science Based English Programme (SBEP) which encapsulates several adjustments in orientation methods and materials to meet the ESL learners’ needs. This kind of learning-centred arrangement will allow not only efficiency of SBEP instruction but also allow the kinds of activities that may not be possible in groups with a wide dispersion of interests. However, the extent to which the research learners encountered difficulties with vocabulary suggests that there is a need to investigate more effective methods of dealing with this issue. Needed research could also be directed into the development of a Science glossary with appropriate language levels for ESL learners. This could include technical scientific terms with examples of how terms can be used.From the outcome of the interviews with educators, it is evident that further research is needed concerning the educators’ English proficiency and Science competence in ESL situations.Teacher EducationD. Ed. (Didactics

Machine Learning for Decision-Support in Distributed Networks

Student Number : 9801145J - MSc dissertation - School of Electrical and Information Engineering - Faculty of EngineeringIn this document, a paper is presented that reports on the optimisation of a system that assists in time series prediction. Daily closing prices of a stock are used as the time series under which the system is being optimised. Concepts of machine learning, Artificial Neural Networks, Genetic Algorithms, and Agent-Based Modeling are used as tools for this task. Neural networks serve as the prediction engine and genetic algorithms are used for optimisation tasks as well as the simulation of a multi-agent based trading environment. The simulated trading environment is used to ascertain and optimise the best data, in terms of quality, to use as inputs to the neural network. The results achieved were positive and a large portion of this work concentrates on the refinement of the predictive capability. From this study it is concluded that AI methods bring a sound scientific approach to time series prediction, regardless of the phenomena that is being predicted