3,857 research outputs found
Research on the health implications of the use of recycled water in South Africa
South Africa has an inadequate and unreliable supply of water. It is expected that water resources will be a limiting factor to development by the year 2020. Reclamation and reuse of sewage effluent is one possible method of supplementing existing supplies. Windhoek has had direct supplementation of its water supply for over a decade. Guidelines for using recycled sewage as a source of potable water are given and South African studies on chemical, microbiological and virological aspects of reclaimed water are reviewed. Epidemiological studies, retrospective in Windhoek and prospective for Cape Town, are discussed
Explaining Citizen Attitudes to Strategies of 'Democratic Defence' in Europe:A resource in response to contemporary challenges to liberal democracy?
It has long been speculated that banning parties from participation in elections may be counterproductive because it might provoke societal resistance. Using the European Social Survey (2002â2010; Nâ=â195,405), our study suggests otherwise. We demonstrate that party bans enjoy the legitimacy of majority support. This holds true irrespective of countriesâ resilience to extremist influences (or lack thereof) resulting from âinstitutional intolerance,â electoral entry barriers and authoritarian legacies. Individual orientations toward the democratic establishment do matter to a small extent: citizens with authoritarian tendencies and low system support are less supportive, while this is less so for citizens with extremist ideological orientations. Even though party bans entail significant democratic dilemmas, this study reveals societal resources supportive of repressive responses to extremist parties
H-ATLAS/GAMA and HeViCS â dusty early-type galaxies in different environments
The Herschel Space Observatory has had a tremendous impact on the study of extragalactic dust. Specifically, early-type galaxies (ETG) have been the focus of several studies. In this paper, we combine results from two Herschel studies â a Virgo cluster study Herschel Virgo Cluster Survey (HeViCS) and a broader, low-redshift Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS)/Galaxy and Mass Assembly (GAMA) study â and contrast the dust and associated properties for similar mass galaxies. This comparison is motivated by differences in results exhibited between multiple Herschel studies of ETG. A comparison between consistent modified blackbody derived dust mass is carried out, revealing strong differences between the two samples in both dust mass and dust-to-stellar mass ratio. In particular, the HeViCS sample lacks massive ETG with as high a specific dust content as found in H-ATLAS. This is most likely connected with the difference in environment for the two samples. We calculate nearest neighbour environment densities in a consistent way, showing that H-ATLAS ETG occupy sparser regions of the local Universe, whereas HeViCS ETG occupy dense regions. This is also true for ETG that are not Herschel-detected but are in the Virgo and GAMA parent samples. Spectral energy distributions are fit to the panchromatic data. From these, we find that in H-ATLAS the specific star formation rate anticorrelates with stellar mass and reaches values as high as in our Galaxy. On the other hand HeViCS ETG appear to have little star formation. Based on the trends found here, H-ATLAS ETG are thought to have more extended star formation histories and a younger stellar population than HeViCS ETG
Birth defects surveillance· A pilot system in the Cape Peninsula
A pilot birth defects surveillance system was established in 1982 as part of an epidemiological baseline study pertaining to potential changes in water quality in the Cape Peninsula. The methodology used for reporting birth defects for two information systems, one hospital-based and the other population- based, utilising statutory notifications of births, is described. Preliminary birth defect rates by cause are presented for a hospital-based system and are consistent with rates reported internationally. The system based on statutory notifications showed gross under-reporting
Risk factors for coronary heart disease in the black population of the Cape Peninsula The BRISK study
A cross-sectional study of risk factors for ischaemic heart disease (IHO) in a random sample of 986 black people aged 15 - 64 years living in the Cape Peninsula revealed a population at lower risk for IHO than other South Africans. Blood pressures of 140/95 mmHg or above were found in 14,4% of males and 13,7% of females. Fifty-two per cent of males and 8,4% of females smoked, while 16,5% of males and 25,8% of females had a total cholesterol (TC) level imparting risk for developing IHO. In this population the TC level is not a good surrogate measure for low-density lipoprotein cholesterol because of the high level of high-density lipoprotein cholesterol (HOLC) found in this population. A protective HOLC/TC ratio of 20% was found in 96% of males and 96,1% of females. When considering the three major reversible IHO risk factors at a high level of risk, 30,8% of males and 12,5% of females had at least one such a risk factor. The population was frequently exposed to the media, with 80% listening to the radio every day and 55% watching television at least once a week. This suggests that a healthy lifestyle could be promoted successfully by means of these media. In addition, schools should promote a healthy lifestyle and the prevention of chronic degenerative diseases should be incorporated into the evolving primary health care services in South Africa
Sexual selection, automata and ethics in George Eliot's The Mill on the Floss and Olive Schreiner's Undine and From Man to Man
This paper brings together two related areas of debate in the latter half of the nineteenth century. The first concerns how the courtship plot of the nineteenth-century novel responded to, and helped to shape, scientific ideas of sexual competition and selection. In The Mill on the Floss (1860), George Eliot strikingly prefigures Darwin's later work on sexual selection, drawing from her own extensive knowledge of the wider debates within which evolutionary theory developed. Maggie Tulliver's characterisation allows Eliot to explore the ethical complexities raised by an increasingly powerful scientific naturalism, where biology is seen to be embedded within morality in newly specific ways. The second strand of the paper examines the extension of scientific method to human mind and motivation which constituted the new psychology. It argues that there are crucial continuities of long-established ethical and religious ideas within this increasingly naturalistic view of human mind and motivation. The contention that such ideas persist and are transformed, rather than simply jettisoned, is illustrated through the example of Thomas Henry Huxley's 1874 essay on automata. Turning finally to focus on Olive Schreiner's Undine (1929) and From Man to Man (1926), the paper explores the importance of these persistent ethical and religious ideas in two novels which remained unpublished during her lifetime. It argues that they produce both difficulty and opportunity for imagining love plots within the context of increasingly assertive biological and naturalistic accounts of human beings
Addressing potential sources of variation in several non-destructive techniques for measuring firmness in apples
Measurements of firmness have traditionally been carried out according to the Magness Taylor (MT) procedure; using a texture analyser or penetrometer in reference texture tests. Non-destructive tests like the acoustic impulse response of acoustic firmness sensors (AFSs), a low-mass impact firmness sensor Sinclair International (SIQ-FT) and impact test (Lateral Impact â UPM) have also been used to measure texture and firmness. The objectives of this study were to evaluate the influence of different sources of variation in these three non-destructive tests and to evaluate their respective capabilities of discriminating between fruit maturity at two different harvest dates, turgidity before and after dehydration treatment and ripening after different storage periods. According to our results, fruit studied an unexpected AFS trend with turgidity. Contact measurements (Lateral Impact â UPM and SIQ-FT) appeared highly sensitive to changes in turgidity, but were less able to follow changes in ripening caused by storage period. Contact measurements were suitable for detecting differences between fruits from different harvest dates and showed higher correlation coefficients with reference texture tests than acoustic measurements. The Lateral Impact â UPM test proved better at separating fruits according to turgidity than the SIQ-FT instrumen
Aspergillus niger Protein EstA Defines a New Class of Fungal Esterases within the α/ÎČ Hydrolase Fold Superfamily of Proteins
AbstractFrom the fungus Aspergillus niger, we identified a new gene encoding protein EstA, a member of the α/ÎČ-hydrolase fold superfamily but of unknown substrate specificity. EstA was overexpressed and its crystal structure was solved by molecular replacement using a lipase-acetylcholinesterase chimera template. The 2.1 Ă
resolution structure of EstA reveals a canonical Ser/Glu/His catalytic triad located in a small pocket at the bottom of a large solvent-accessible, bowl-shaped cavity. Potential substrates selected by manual docking procedures were assayed for EstA activity. Consistent with the pocket geometry, preference for hydrolysis of short acyl/propyl chain substrates was found. Identification of close homologs from the genome of other fungi, of which some are broad host-range pathogens, defines EstA as the first member of a novel class of fungal esterases within the superfamily. Hence the structure of EstA constitutes a lead template in the design of new antifungal agents directed toward its pathogenic homologs
Exploiting chemical ecology to manage hyperparasitoids in biological control of arthropod pests
Insect hyperparasitoids are fourth trophic level organisms that commonly occur in terrestrial food webs, yet they are relatively understudied. These top-carnivores can disrupt biological pest control by suppressing the populations of their parasitoid hosts, leading to pest outbreaks, especially in confined environments such as greenhouses where augmentative biological control is used. There is no effective eco-friendly strategy that can be used to control hyperparasitoids. Recent advances in the chemical ecology of hyperparasitoid foraging behavior have opened opportunities for manipulating these top-carnivores in such a way that biological pest control becomes more efficient. We propose various infochemical-based strategies to manage hyperparasitoids. We suggest that a push-pull strategy could be a promising approach to âpushâ hyperparasitoids away from their parasitoid hosts and âpullâ them into traps. Additionally, we discuss how infochemicals can be used to develop innovative tools improving biological pest control (i) to restrict accessibility of resources (e.g. sugars and alternative hosts) to primary parasitoid only or (ii) to monitor hyperparasitoid presence in the crop for early detection. We also identify important missing information in order to control hyperparasitoids and outline what research is needed to reach this goal. Testing the efficacy of synthetic infochemicals in confined environments is a crucial step towards the implementation of chemical ecology-based approaches targeting hyperparasitoids. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
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