Alternating current source to voltage source converter

Abstract: A direct alternating current source to voltage source converter, which does not employ energy storage components, is presented. Conversion is done by a current steering mechanism in the form of a current transformer with two secondary windings. The direct conversion concept, basic circuit, simulation and experimental results of a reduced scale model are presented

Nonlinearities in stock return prediction: A Blended Approach

Our prior research indicates that there are periods within which nonlinear stock selection models outperform their linear counterparts in the South African equity market. In order to explore the nonlinearities in stock return prediction, we propose a blended stock selection technique that has the potential of diversifying the risk of inaccurate forecasts of the linear and nonlinear models. The proposed technique has an objective of optimizing the Qian and Hua (2003) information ratio, which constitutes to the maximization of the forecasting accuracy per unit of forecasting volatility. The blended stock selection model is found to outperform the respective linear and nonlinear models in an out-of-sample fractile analysis on a risk-adjusted basis for South African stocks over the period from 2002 to 2007.Department of HE and Training approved lis

Comorbidities between tuberculosis and common mental disorders: A scoping review of epidemiological patterns and person-centred care interventions from low-to-middle income and BRICS countries

Background : There is increasing evidence that the substantial global burden of disease for tuberculosis unfolds in concert with dimensions of common mental disorders. Person-centred care holds much promise to ameliorate these comorbidities in low-tomiddle income countries and emerging economies. Towards this end, this paper aimed to review 1) the nature and extent of tuberculosis and common mental disorder comorbidity and 2) person-centred tuberculosis care in low-to-middle income countries and emerging economies. Main text : A scoping review was conducted of English-language studies published from 2000-2019 in peer-reviewed and grey literature, using established guidelines, for each of the study objectives. Four broad tuberculosis/mental disorder comorbidities were described in the literature, namely alcohol use and tuberculosis, depression and tuberculosis, anxiety and tuberculosis, and general mental health and tuberculosis. Rates of comorbidity varied widely across countries for depression, anxiety, alcohol use and general mental health. Alcohol use and tuberculosis were significantly related, especially in the context of poverty. The initial tuberculosis diagnostic episode had substantial socio-psychological effects on service users. While men tended to report higher rates of alcohol use and treatment default, women in general had worse mental health outcomes. Older age and a history of mental illness were also associated with pronounced tuberculosis and mental disorder comorbidity. Person-centred tuberculosis care interventions were almost absent, with only one study from Nepal identified. Conclusions : There is an emerging body of evidence describing the nature and extent of tuberculosis and mental disorders comorbidity in low-to-middle income countries. Despite the potential of person-centred interventions, evidence is limited. This review highlights a pronounced need to address psychosocial comorbidities with TB in LMICs, where models of person-centred TB care in routine care platforms may yield promising outcomes

Impact of University engagement on environmental resilience of urban spaces in Asia and Africa. SUEUAA Thematic Paper Series, TPS 103/19

By 2030 most of the globes inhabitants will be living with cities. It is therefore important that cities are resilient to sustenance and energy challenge in the face of increasing demands from population expansion and increasing environmental variability and uncertainty brought about by intensifying climate change. The Strengthening Urban Engagement of Universities in Asia and Africa (SUEUAA) project aims to enhance university engagement capacity in this context and optimise engagement strategy to maximise impact in urban areas. We use the term ‘environmental resilience’ to encapsulate both energy and sustenance challenges. We believe these must be tackled in a holistic manner as there are intimate links between the production and usage of energy, food and water and consequent generation and disposal of waste. This paper focuses on the experiences and vision of SUEUAA partners in Johannesburg (South Africa), Dar es Salaam (Tanzania), Duhok (Iraq), Sanandaj (Iran), and Manila (Philippines), so it encapsulates views and solutions for engagement strategies on several environmental challenges facing cities in very different climatic situations

Impact of University engagement on environmental resilience of urban spaces in Asia and Africa. SUEUAA Thematic Paper Series, TPS 103/19

By 2030 most of the globes inhabitants will be living with cities. It is therefore important that cities are resilient to sustenance and energy challenge in the face of increasing demands from population expansion and increasing environmental variability and uncertainty brought about by intensifying climate change. The Strengthening Urban Engagement of Universities in Asia and Africa (SUEUAA) project aims to enhance university engagement capacity in this context and optimise engagement strategy to maximise impact in urban areas. We use the term ‘environmental resilience’ to encapsulate both energy and sustenance challenges. We believe these must be tackled in a holistic manner as there are intimate links between the production and usage of energy, food and water and consequent generation and disposal of waste. This paper focuses on the experiences and vision of SUEUAA partners in Johannesburg (South Africa), Dar es Salaam (Tanzania), Duhok (Iraq), Sanandaj (Iran), and Manila (Philippines), so it encapsulates views and solutions for engagement strategies on several environmental challenges facing cities in very different climatic situations

Impact of University engagement on environmental resilience of urban spaces in Asia and Africa

By 2030 most of the globes inhabitants will be living with cities. It is therefore important that cities are resilient to sustenance and energy challenge in the face of increasing demands from population expansion and increasing environmental variability and uncertainty brought about by intensifying climate change. The Strengthening Urban Engagement of Universities in Asia and Africa (SUEUAA) project aims to enhance university engagement capacity in this context and optimise engagement strategy to maximise impact in urban areas. We use the term 'environmental resilience' to encapsulate both energy and sustenance challenges. We believe these must be tackled in a holistic manner as there are intimate links between the production and usage of energy, food and water and consequent generation and disposal of waste. This paper focuses on the experiences and vision of SUEUAA partners in Johannesburg (South Africa), Dar es Salaam (Tanzania), Duhok (Iraq), Sanandaj (Iran), and Manila (Philippines), so it encapsulates views and solutions for engagement strategies on several environmental challenges facing cities in very different climatic situations

High-Throughput Discovery of Hf Promotion on the Formation of Hcp Co and Fischer-Tropsch Activity

A proxy-based high-throughput experimental approach was used to explore the stability and activity of Co-based Fischer Tropsch Synthesis catalysts with different promoters on various supports. The protocol is based on the estimation by XRD of active phase, Co, particle size and relative amounts of crystalline phases, Co to support. Sequential libraries samples enabled exploration of four Co loadings with five different promoters on six support materials. Catalysts stable to aging in syngas, displaying minimal change of particle size or relative area, were evaluated for their activity under industrial conditions. This procedure identified SiC as support for stable catalysts and a combination of Ru and Hf to promote the formation hcp Co. Unsupported bulk samples of Co with appropriate amounts of Ru and Hf revealed that the formation of hcp Co is independent of the support. The hcp Co containing catalyst presented the highest catalytic activity and C5+ selectivity amongst the samples tested in this study confirming the effectiveness of the proxy-based high-throughput method.</jats:p

African horse sickness: The potential for an outbreak in disease-free regions and current disease control and elimination techniques

African horse sickness (AHS) is an arboviral disease of equids transmitted by Culicoides biting midges. The virus is endemic in parts of sub-Saharan Africa and official AHS disease-free status can be obtained from the World Organization for Animal Health on fulfilment of a number of criteria. AHS is associated with case fatality rates of up to 95%, making an outbreak among naïve horses both a welfare and economic disaster. The worldwide distributions of similar vector-borne diseases (particularly bluetongue disease of ruminants) are changing rapidly, probably due to a combination of globalisation and climate change. There is extensive evidence that the requisite conditions for an AHS epizootic currently exist in disease-free countries. In particular, although the stringent regulations enforced upon competition horses make them extremely unlikely to redistribute the virus, there are great concerns over the effects of illegal equid movement. An outbreak of AHS in a disease free region would have catastrophic effects on equine welfare and industry, particularly for international events such as the Olympic Games. While many regions have contingency plans in place to manage an outbreak of AHS, further research is urgently required if the equine industry is to avoid or effectively contain an AHS epizootic in disease-free regions. This review describes the key aspects of AHS as a global issue and discusses the evidence supporting concerns that an epizootic may occur in AHS free countries, the planned government responses, and the roles and responsibilities of equine veterinarians.Matthew Robin's clinical training scholarship was funded by the Horserace Betting Levy Board.http://onlinelibrary.wiley.com/journal/10.1001/(ISSN)2042-33062017-09-30hb2017Companion Animal Clinical Studie

MDCT/CTA essentials course, Report by ESOR musculoskeletal visiting scholarship

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Enzymes in Winemaking: Harnessing Natural Catalysts for Efficient Biotransf ormations - A Review

Enzymes play a definitive role in the ancient and complex process of winemaking. From a scientific and technical point of view, wine can be seen as the product of enzymatic transformation of grape juice. From the pre-fermentation stage, through fermentation, post-fermentation and aging, enzymes are the major driving forces catalysing various biotransformation reactions. These biocatalysts originate not only from the grape itself but also from yeasts and other microbes (fungi and bacteria) associated with vineyards and wine cellars. Through better understanding of these enzymatic activities, winemakers have come to learn how to control the unwanted enzymes while optimising the desired activities. Today, winemakers reinforce and extend the action of these endogenous enzymes by the judicious application of an ever-increasing spectrum of commercial enzyme preparations. These enzyme preparations are applied to winemaking with the aims of improving the clarification and processing of wine, releasing varietal aromas from precursor compounds, reducing ethyl carbamate formation and lowering alcohol levels. This review article summarises the most important enzymes applied to winemaking, the nature and structure of their substrates, and the reactions catalysed by these enzymes. This paper also reviews the limitations of the endogenous enzymes derived from grapes and microbes present in must and wine, along with the effects of commercial enzyme preparations on process technology and the quality of the final product. Prospects of developing wine yeast strains expressing tailored enzymes are also highlighted