Dynamic one-sided out-of-plane behavior of unreinforced-masonry wall restrained by elasto-plastic tie-rods

Past earthquakes have shown the high vulnerability of existing masonry buildings, particularly to out-of-plane local collapse mechanisms. Such mechanisms can be prevented if façades are restrained by tie rods improving the connections to perpendiculars walls. Whereas in the past only static models have been proposed, herein the nonlinear equation of motion of a monolithic wall restrained by a tie rod is presented. The façade, resting on a foundation and adjacent to transverse walls, rotates only around one base pivot and has one degree of freedom. Its thickness is explicitly accounted for and the tie rod is modeled as a linear elastic—perfectly plastic spring, with limited displacement capacity. The model is used to investigate the response to variations of wall geometry (height/thickness ratio, thickness), tie rod features (vertical position, length, prestress level), and material characteristics (elastic modulus, ultimate elongation, yield strength) typical of historical iron. The most relevant parameter is the steel strength, whereas other characteristics play minor roles allowing to recommend reduced values for pre-tensioning forces. The force-based procedure customary in Italy for tie design is reasonably safe and involves protection also against collapse, although probably not enough as desirable

Chronotype in the South African population: the influence of longitudinal location

Includes bibliographical references.Most human beings experience the pull of three different daily timers, the solar clock, their endogenous circadian clock and the societal clock. Solar time is generated by the Earth’s revolution on its axis, resulting in its surface being alternately exposed to and shielded from the sun every 24 hours. The endogenous clock, or circadian oscillator, is driven by a network of transcriptional translational feedback loops, and has a period of close to 24 hours. The circadian oscillator is synchronised to the 24 hour light-dark cycle of the solar clock. The third timer is the standardised societal clock that organises and schedules work, school, transport, appointments and free time in a 24 hour period. The way an individual’s endogenous clock synchronises to the solar clock, through advances or delays relative to sunrise and sunset, results in a phenomenon known as diurnal preference or chronotype. A person may have a morning-chronotype, where they enjoy rising and being active early in the day, an evening-chronotype where they prefer to be active later in the day into the late night, retiring in the early morning hours, or have no strong preference for early or late rising. This renders it easy for some to cope with the demands of the societal clock and others to struggle. Chronotype has both genetic and environmental influences. As society’s schedule is governed by the standardised clock, it was hypothesised that chronotype may be influenced by one’s longitudinal location within a time zone. South Africa presents an interesting case because although it uses just one time zone, in the most Easterly regions of the country, the sun rises and sets up to an hour earlier than in the most Westerly regions throughout the year. Sunrise times have an impact on the way the endogenous clock synchronises to the solar clock. It was hypothesised firstly, that South Africans living in the East of the country may have a greater preference for mornings (more morningchronotypes) than those living in the West; and secondly, that this difference would not be due to genetic differences in the populations, particularly two gene polymorphisms previously shown to influence chronotype. Therefore the aims of this study were to describe and compare the distribution of chronotype in Eastern (n=222) and Western (n=205) sample populations with the use of a validated tool, the Horne–Östberg Morningness, Eveningness Questionnaire. Secondly to describe the genotype and allelic frequency distributions of the PER2 single nucleotide polymorphism (SNP) G3853A (rs934945) in the Eastern (n= 184) and Western (n=186) populations, and the PER3 variable number tandem repeat (VNTR) polymorphism in the Eastern (n=143) and Western (n=176) populations from buccal cell samples. There was a significantly higher proportion of morning-types in the Eastern population (60.6%) than in the Western population (40.5%) (p<0.001). Whereas there were higher proportions of neither-types and evening-types in the Western population (50.8% and 8.7% respectively) than in the Eastern population (35.1% and 4.3% respectively) (p<0.001). There were no significant differences in distribution of the PER2 genotype (p=0.121) and allele frequencies (p=0.051) between the Eastern and Western populations nor in the PER3 genotype (p=0.879) and allele (p=0.075) frequencies. Although previous studies have shown associations between chronotype and PER2 G3853A and PER3 VNTR genotypes, no significant associations were observed in either the Eastern (PER2 p=0.769; PER3 p=0.221) or the Western (PER2 p=0.584; PER3 p=0.733) populations. These findings indicate that, in South African populations, longitude influences chronotype independently of genotype. Factors that may contribute to this may be the difference in the rising times of the sun, which is exacerbated to some extent by the study areas being at dissimilar latitudes and thus experiencing slight differences in climate. The impact of the differences in chronotype but the maintenance of the same societal temporal organisation in the Eastern and Western regions were not assessed. However, they may be revealed by investigating certain general health indicators in such as quality of sleep and prevalence of depressive symptoms which are affected when there is incongruence between societal time and endogenous time

Towards a Model of a Critical Pedagogy in Malawian Universities

Quality university education is important for achieving national aspirations as stated in higher education policy frameworks in Malawi. The major education policy documents in Malawi: The Policy and Investment  Framework and the Malawi National Education Sector Plan recognise the importance of university education for knowledge production and its  dissemination and for the facilitation of a culture of peace that is conducive and critical for socio-economic, political and industrial development. In an attempt to align policy to achieving these goals, the policy documents outline the following policy directions: improving access, achieving equity, enhancing quality, improving financial management and improving the management and planning of the university sector. This paper shows that what is lacking however is a philosophical foundation on which to ground university pedagogy so as to train critical citizens able to produce knowledge and advance civic values. Thus, this paper conceptualises a model of critical pedagogy useful in enhancing critical citizenship in Malawi. The paper is conceptual other than empirical in its approach.Keywords: Quality assurance; Critical pedagogy; Critical citizenship

Social security system reform : the case of Malawi

Mestrado em Ciências ActuariaisThis thesis examines the Malawi pension fund reform using an integrated simulation model. The aim is to explore why the Malawi government moved from Pay as you go (PAYG) system to define contribution (DC) system. Malawi is a relatively young country and its pension schemes are deficient in design, financing, execution and administration. Malawi has persistent macroeconomic fluctuations and an unstable financial sector that make effective pension fund management challenging. Also there are high inflation rates and politically motivated low-yield investment loans. The thesis assumes that in Malawi an average person retires by 50 years and the maximum age of death is 70. The average starting wage ranges from 65,000-75,000 Mk. The contribution rate is 15% of payroll with a transaction cost of 5% of wages. The common investment strategy is a 50-50-0-0-0 approach, i.e. 50% of assets are allocated to bank deposits and government bonds respectively. In addition a risk return analysis is employed to test the portfolio riskiness. The test include the Sharpe ratio, the Jensen measure and the Treynor measure. It was observed following the simulation tests that replacement rates are higher when retirement age rises to 60 or 65, but retiring at 50 had very low replacement rates. Meaning, pensioner can get favourable retirement income when he/she retires at 65 but this is a problem since life expectancy is 54 years. The portfolio risk test indicated very low results meaning low risks. This is as a result of allocating the funds in less risky assets i.e. government bonds which have low investments yield trickling down to low pensions. To improve the current pension system, Malawi needs to redesign its pension system to tackle the life expectancy problem, diversify pension fund portfolios to achieve a high and stable return, and invest in the economy in order to have a stable macro-economy that can protect the real value of pension assets.Esta tese examina o fundo de pensão de reforma do Malawi usando um modelo de simulação integrada. O objetivo é explorar por que o governo do Malawi passou do sistema Pay as you go (repartição ) para um sistema de contribuição definida (capitalização). Malawi é um país relativamente jovem e os seus regimes de pensões são deficientes em design, financiamentos, execução e administração. Malawi tem flutuações macroeconômicas persistentes e um sector financeiro instável que fazem a gestão eficaz de fundos de pensões desafiante. Além disso, existem altas taxas de inflação e politicamente motivadas empréstimos de investimento de baixo rendimento. A tese parte do princípio de que no Malawi uma pessoa média se aposenta aos 50 anos e de que a idade máxima de morte é de 70 . O salário médio inicial varia de 65,000-75,000 Mk. A taxa de contribuição é de 15% do salário, com um custo de transação de 5% dos salários. A estratégia comum de investimento é uma abordagem 50-50-0-0-0 , ou seja, 50% dos activos são alocados para os depósitos bancários e títulos do governo, respetivamente. Além disso, uma análise de retorno de risco é utilizada para testar o grau de risco da carteira. O teste inclui o índice de Sharpe, a medida Jensen e a medida Treynor. Observou-se nos ensaios de simulação que as taxas de substituição são mais elevados quando a idade da reforma sobe para 60 ou 65 anos, mas se a reforma for aos 50 anos obtêm-se taxas de substituição muito baixas. Ou seja, o pensionista pode obter uma pensão favorável quando se aposenta aos 65 anos , mas existe um problema, já que a expectativa média de vida é de 54 anos. O teste de risco da carteira dá resultados muito baixos indicando baixo risco. Este é o resultado da alocação dos recursos em ativos de menor risco, ou seja, títulos do governo, produzindo pensões baixas. Para melhorar o actual sistema de pensões, Malawi precisa redesenhar o seu sistema de pensões para enfrentar o problema da expectativa de vida, diversificar carteiras dos fundos de pensões para conseguir um retorno alto e estável, e investir na economia, a fim de ter uma macroeconomia estável, que pode proteger o valor real dos ativos de pensões

Conceptualising the right to enjoy benefits of scientific progress and exploring its potential to enhance access to effective diagnosis and treatment of drug-resistant tuberculosis in South Africa

The lack of access to effective diagnosis and treatment of drug-resistant tuberculosis (DR-TB) remains a persistent global challenge. Human rights arguments for access to treatment mostly focus on the right to health. However, a key challenge in access to effective diagnosis and treatment is the glaring absence of scientific research in neglected diseases such as TB. This thesis sets out to elaborate the right to enjoy the benefits of scientific progress and explore its potential to increase scientific research in DR-TB and consequently enhance access to effective diagnosis and treatment in South Africa. This research project was conducted using three interrelated sub-studies; a legal analysis sub-study which examines the current conceptualisation of the REBSP in international law; a policy analysis sub-study which interrogates South Africa’s legal and policy efforts towards the realisation of the REBSP and access to diagnosis and treatment for DR-TB; and a qualitative sub-study which explores the South African context regarding research and development (R&D) in general, and in DR-TB in particular. The qualitative sub-study included 17 stakeholders who are active in TB R&D, advocacy and policy work, from human rights and research institutions, government agencies, civil society organisations, and donor agencies. This thesis finds that the REBSP essentially ensures two things, namely the production of science and access to the benefits of scientific progress. However, most countries including South Africa have systems, policies and resources aimed at advancing the production of science but lack similar systems, policies and resources to purposely ensure the enjoyment of the benefits from scientific progress. Internationally, there is no clear guidance on the interpretation of the REBSP, making it difficult for states to domesticate it in their national policies and framework laws. A General Comment by a UN human rights monitoring body is therefore urgently needed to secure global consensus on the interpretation of the REBSP. In the meanwhile, South Africa can still draw inspiration for the REBSP and together with the right to health, use it to advance access to DR-TB diagnosis and treatment alongside many other interventions. To enable better access to effective diagnosis and treatment of DR-TB, this thesis recommends that South Africa i) develops systems that would make scientific progress and results accessible, and affordable; ii) removes system and regulatory barriers that hinder the conduct of research or that delay registration of new drugs; iii) monitors and regulates the conduct of third parties and prevent them from exploiting communities; iv) encourages pharmaceutical companies to provide free access to successful treatment and tools in communities where trials are conducted; and v) mobilises financial and technical resources and allocates them to DR-TB researchfrom drug discovery through to implementation science

Evaluating Machine Learning Model Stability for Software Bug Prediction

Large software systems are implemented using many different programming languages and scripts, and consequently the dependencies between their components are very complex. It is therefore difficult to extract and understand these dependencies by solely analyzing the source code, so that failure risks can be detected accurately. On the other hand, it is a common practice for software engineers to keep track of process related metrics such as the number of times a component was maintained, with which other components it has been co-committed, whether the maintenance activity was a bug-fixing activity, and how many lines of source code have been altered. These data provide valuable information to be used for training a machine learning model and for devising metrics which can predict the risk associated with a future failure of a component due to maintenance activities in this or in another component related to it

Exploring experiences of HIV counsellors towards the HIV counselling and testing policy in Zambia’s public urban health centers

Includes abstract. Includes bibliographical references

Hepatitis B and C Viruses

Hepatitis B and C viruses (HBV/HCV) are among the leading causes of liver disease. HBV is a partially double-stranded circular DNA virus whose genome is approximately 3200 bases with four overlapping open reading frames (ORFs) and belongs to Hepadnaviridae family. HBV prevalence varies worldwide, with high rates reported in low-income countries. Approximately 90% of HBV infections are acute, 10% progress to chronic infection among adult patients. Although HBV can be prevented by immunisation, there is no licenced HCV vaccine. HCV is a positive-sense single-stranded RNA (+ssRNA) virus belonging to Flaviviridae family. The HCV global epidemiology varies, with high prevalence rates reported in low-income countries. Approximately 80% of acutely HCV-infected individuals develop chronic hepatitis disease, while 20% resolve spontaneously. Both HBV and HCV infections can result in both acute and chronic hepatitis, ranging in severity from asymptomatic to a life-threatening disease. The HBV and HCV are transmitted through contact with contaminated blood or its products. As compared with mono-infection, HBV/HCV co-infection has higher risk of liver damage. Thus, individuals who have active HBV and HCV infections are likely to be HCV-dominant with a high HCV viral load and low or undetectable HBV DNA levels