Academic research and HIV/AIDS in South Africa

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Relative risk of HIV infection among young men and women in a South African township

The prevalence of HIV infection in Africa is substantially higher among young women than it is among young men. Biological explanations of this difference have been presented but there has been little exploration of social factors. In this paper we use data from Carletonville, South Africa to explore various social explanations for greater female infection rates. This paper reports on data from a random sample of 507 people between 13 and 24 years old. Subjects were tested for HIV, as well as other sexually transmitted infections (STIs), and answered a behavioural questionnaire. The age-prevalence of HIV infection differs between men and women with considerably higher rates of increase with age among young women. The age of sexual debut did not differ significantly between men and women (15.9 and 16.3 years, respectively) and below the age of 20 years there was no difference in the number or distribution of the number of sexual partners reported by men or women. The risk of infection per partnership was substantially higher among women than among men. Women have sexual partners who are, on average, about five years older than they are with some variation with age. Scaling the age-prevalence curve for men by the age of their sexual partners gives a curve whose shape is indistinguishable from that for women but is about 30% lower for men than for women. In terms of social explanations for HIV rates among women, the data indicates that this difference can be explained by the relative age of sexual partners, but not by other factors explored. In addressing the epidemic among young women it will be essential to deal with the social factors that lead young women to select their partners from older-age cohorts and that shape their sexual networking patterns

Low-lignin hull in oat

Non-Peer ReviewedThe use of whole oat in feed rations is restricted due to low digestibility of the hull. AC Assiniboia hulls have decreased acid detergent lignin (ADL) content. AC Assiniboia was crossed with OT 775 and the resulting lines were measured for ADL content. The ratio of F4:5 lines with low to normal ADL concentration fit a 1:1 genetic ratio. Indicating that the low-lignin trait is controlled by a single major gene. ADL concentration was correlated with hull colour and acid detergent fiber concentration. ADL concentration was not correlated with the protein or fat concentration of the groat. Simple inheritance of the low-lignin trait indicates that it can be incorporated into the oat breeding program. Furthermore, ADL concentration is not correlated with groat fat so a cultivar with a low lignin hull and high fat groat can be developed

A Nonparametric Method for the Derivation of α/β Ratios from the Effect of Fractionated Irradiations

Multifractionation isoeffect data are commonly analysed under the assumption that cell survival determines the observed tissue or tumour response, and that it follows a linear-quadratic dose dependence. The analysis is employed to derive the α/β ratios of the linear-quadratic dose dependence, and different methods have been developed for this purpose. A common method uses the so-called Fe plot. A more complex but also more rigorous method has been introduced by Lam et al. (1979). Their method, which is based on numerical optimization procedures, is generalized and somewhat simplified in the present study. Tumour-regrowth data are used to explain the nonparametric procedure which provides α/β ratios without the need to postulate analytical expressions for the relationship between cell survival and regrowth delay

The Relationship of Suicides, Guns and Mass Shootings in the United States: An Ethical Dilemma

Suicides have been a reality of life due to many factors across nations. In the United States alone, about 30,000 to 40,000 individuals are likely to take their own life this year. During the Covid-19 Corona virus months, telephone calls to the suicide hotlines in the United States have increased significantly. As such, suicide is a huge, complex and costly problem in our society even when people are not dealing with a pandemic like Covid-19 and racial inequalities. In this study, we look at the relationship between suicides, guns and mass shootings based on age, gender and ethnicity, using data of 3,238-recorded suicides in South Florida’s Broward County

Application of surface-modified metal hydrides for hydrogen separation from gas mixtures containing carbon dioxide and monoxide

Application of surface-modified MH material for H2 separation using temperature/pressure swing absorption–desorption was studied. The substrate alloy had the following composition LaNi3.55Co0.75Al0.4-Mn0.3, and the surface modification was carried out through fluorination followed by aminosilane functionalization and electroless deposition of Pd. The material was found to have good poisoning tolerance towards surface adsorbates, even for the large (rv1.5 kg) batches. Feasibility of its application for H2 separation from gas mixtures (up to 30% CO2 and 100 ppm CO) was demonstrated by testing of a prototype H2 separation system (rv280 g of MH in two reactors), and H2 separation reactor (0.75 kg of MH). The H2 separation was characterized by stable performances in the duration of 250 absorption/desorption cycles. However, the total process productivity was found to be limited by the sluggish H2 absorption (partial H2 pressure 62.5 bar, temperature below 100 °C). In the presence of CO2 and CO, additional deceleration of H2 absorption was observed at space velocities of the feed gas below 5000 hWeb of Scienc

Perceptions About The ISO 9000 (2000) Quality System Standard Revision And Its Value: The Dutch Experience

The aim of the research reported in this paper is to assess the relative value of the 2000 version of the ISO 9000 series of quality management system standards in comparison to the 1994 version. 773 organisations in the Netherlands which have all been certified to the ISO 9000 standard were surveyed (a response rate of 21.4%) and of these only 22 had not yet converted to the 2000 version of the standard. Amongst the major findings are an overall positive perception of the value of the ISO 9000 (2000) quality system standard and a consistently higher appreciation of the 2000 version compared to the 1994 version

The E-Business Research Network: summary of the results of the Dutch pilot survey

A project has been started with the intention to develop an E-Business Research Network on E-business related research in business and management. The initiative has been taken in co-operation between Erasmus University and UMIST to develop a project in which the first stage concerns the development of a database of researchers and their activities in e-business related research in business and management. The next stage will be to investigate the needs in companies in relation to e-business. It is hoped that an Internet-based database will stimulate interaction and communication between the supply and demand sides of e-business related research. This assumption is based on our previous research in Quality Management conducted in the early to mid 1990's. This paper describes the project and also summarises the results of the first pilot questionnaire based on responses from researchers at universities in The Netherlands

Estimations of changes of the Sun's mass and the gravitation constant from the modern observations of planets and spacecraft

More than 635 000 positional observations (mostly radiotechnical) of planets and spacecraft (1961-2010), have been used for estimating possible changes of the gravitation constant, the solar mass, and semi-major axes of planets, as well as the value of the astronomical unit, related to them. The analysis of the observations has been performed on the basis of the EPM2010 ephemerides of IAA RAS in post-newtonian approximation. The obtained results indicate on decrease in the heliocentric gravitation constant per year at the level $\dot {GM_{Sun}}/GM_{Sun} = (-5.0 \pm 4.1) 10^{-14} (3\sigma).$ The positive secular changes of semi-major axes $\dot a_i/a_i$ have been obtained simultaneously for the planets Mercury, Venus, Mars, Jupiter, Saturn, as expected if the geliocentric gravitation constant is decreasing in century wise. The change of the mass of the Sun $M_{Sun}$ due to the solar radiation and the solar wind and the matter dropping on the Sun (comets, meteors, asteroids and dust) was estimated. Taking into account the maximal limits of the possible $M_{Sun}$ change, the value $\dot G/G$ falls within the interval $-4.2\cdot10^{-14} < \dot G/G < +7.5\cdot10^{-14}$ in year with the 95% probability. The astronomical unit (au) is only connected with the geliocentric gravitation constant by its definition. In the future, the connection between $GM_{Sun}$ and au should be fixed at the certain time moment, as it is inconvenient highly to have the changing value of the astronomical unit.Comment: 20 pages, 4 tables, accepted for publication in Solar System Research, 2011 (Astronomicheskii vestnik