8,473 research outputs found

    Analyses of collective flow and space-time evolution based on relativistic hydrodynamical model

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    We numerically solve fully (3+1)-dimensional relativistic hydrodynamical equation with the baryon number conservation law. For realistic initial conditions we adopt the results from the event generator (URASiMA). Using this model we discuss collective flow.Comment: 4 pages, 11 figures, to apper in Proceedings of Quark Matter '9

    Sport and recreation activity patterns of 12-year-old learners at a city private primary school

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    Published ArticleThe new millennium brought about many changes, including changes in the physical activity patterns of children. Children are labelled as the "screen generation". Owing to the wide exposure to computers, television, play stations and cellphones, children tend to lead more sedentary lifestyles as their age increases. A survey was done at a city private primary school to determine the physical activity patterns of the Grade 6 (12 year old) learners (N=63, 33 boys and 30 girls). A self-constructed questionnaire, based on the activities the school offers and on the extramural activities the learners participate in, was used to measure the learners' physical activity patterns and to obtain data about their reasons and key motivators for participation. The responses show that the same group of learners participates in almost all the activities offered. The main problem clearly concerned learners who were uninvolved in all physical activities. Schools were identified as the key element to promote physical activity among learners (Vidyya, 2002:4; Aarnio, 2003:27). The activities must be positive and enjoyable to keep learners motivated and interested in future participation

    The management of a policy implementation project: the disastrous Gauteng Mental Health Marathon Project

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    The widely reported disastrous Gauteng Mental Health Marathon Project caused the deaths of about 144 vulnerable individuals. The purpose of this contribution is to make sense of the latter by providing a chronological reconstruction of the main series of events. This is followed by a selection of the most appropriate theoretical lenses for identifying those implausible events and for comprehensively redrafting this narrative to gain understanding. The sensemaking approach was selected for the simplicity in guiding the sense-maker with naïve questions through the messy field of discrepancies. With this disastrous policy implementation project study in mind, we have asked: “Why do policy implementation projects become disastrous?” and “How can policy implementation projects be vision aligned?” As this specific case of policy implementation projects has been intensively and widely scrutinised in the public domain, we have relied nearly exclusively on publicly available material. In doing so, researchers acknowledge that there are numerous other perspectives and stories that we have not sourced and analysed. For the purpose of this sensemaking process, three interrelated lenses were used, namely the policy regime lens, the policy commitment lens and the political-administrative interface lens. However, we acknowledge that our selection and use of these theoretical lenses are not entirely exhaustive and adequate. This study has found that the all-inclusive national healthcare policy regime has been attenuated by the Gauteng Department of Health (GDoH) to the exclusion of the national policy intent and the wide variety of legitimate healthcare stakeholders. We have argued that the behaviour of the GDoH in this saga can be attributed, inter alia, to the situational theory of policy commitment. Furthermore, the study found that the relationship between the political office bearer and the Head of Department (HoD) in our case, was not at all equal and complementary; the Member of the Executive Council (MEC) overstepped in the sphere of public administration, while the HoD did not sufficiently execute his legal authority as accounting officer. Lastly, it was found that the operational project management process focused almost exclusively on removing the mental healthcare users from the Life Healthcare Esidimeni facilities before 30 June 2016, without evidence that those facilities to which they were transferred, would constitute the envisaged improved mental healthcare for them. This case study has shown that it is possible through retrospective sensemaking to creatively rectify the errors of the past and replace them with an envisaged future storyline.European UnionPublic Administration and Managemen

    Follow-up of a suspected excess of brain tumours among Namibian children

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    The original publication is available at http://www.samj.org.zaTo the Editor: The aim of this follow-up study was to further investigate a suggested excess of childhood brain tumours (CBT) among Herero children in Namibia from 1983 to 1988. Incidence rates of primary brain tumours among Herero children were found to be 4 times higher than rates among Namibian children in any of the 10 other tribal groups or among children of European origin. The causes of CBTs remain largely unknown. The only established causes are ionizing radiation and predisposing inherited syndromes. A particularly compelling hypothesis is that exposure during gestation to N-nitroso compounds (NOCs) may lead to the development of CBT. This hypothesis was suggested by experimental work in which 100% production of nervous system (NS) tumours in rat offspring resulted from transplacental exposure to the neurocarcinogen ethylnitrosourea (ENU) or to low levels of the precursor compounds sodium nitrite and ethyl urea added to the food and drinking water of pregnant rat

    Functional consequences of sphingomyelinase-induced changes in erythrocyte membrane structure.

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    Inflammation enhances the secretion of sphingomyelinases (SMases). SMases catalyze the hydrolysis of sphingomyelin into phosphocholine and ceramide. In erythrocytes, ceramide formation leads to exposure of the removal signal phosphatidylserine (PS), creating a potential link between SMase activity and anemia of inflammation. Therefore, we studied the effects of SMase on various pathophysiologically relevant parameters of erythrocyte homeostasis. Time-lapse confocal microscopy revealed a SMase-induced transition from the discoid to a spherical shape, followed by PS exposure, and finally loss of cytoplasmic content. Also, SMase treatment resulted in ceramide-associated alterations in membrane-cytoskeleton interactions and membrane organization, including microdomain formation. Furthermore, we observed increases in membrane fragility, vesiculation and invagination, and large protein clusters. These changes were associated with enhanced erythrocyte retention in a spleen-mimicking model. Erythrocyte storage under blood bank conditions and during physiological aging increased the sensitivity to SMase. A low SMase activity already induced morphological and structural changes, demonstrating the potential of SMase to disturb erythrocyte homeostasis. Our analyses provide a comprehensive picture in which ceramide-induced changes in membrane microdomain organization disrupt the membrane-cytoskeleton interaction and membrane integrity, leading to vesiculation, reduced deformability, and finally loss of erythrocyte content. Understanding these processes is highly relevant for understanding anemia during chronic inflammation, especially in critically ill patients receiving blood transfusions

    Comparative value of dry-rolled corn, distiller’s dried grains, and wheat middlings for receiving diets

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    Two 28-day receiving experiments were conducted using 620 exotic × British cross steers to evaluate differences in growth performance, morbidity, and mortality when fed diets containing dry-rolled corn, distiller’s dried grains with solubles, or wheat middlings. All diets contained approximately 60% concentrate and 40% roughage (alfalfa hay). Gain and efficiency tended to be poorer for cattle fed the wheat middling-based diet than for those fed corn. No notable differences were evident in terms of the percentage of cattle treated for respiratory disease. Feed intake and daily gain were improved slightly when corn was replaced by distiller’s dried grains, but efficiency was not changed. However, the incidence of respiratory disease also was higher for cattle fed the distiller’s grains diet in comparison to corn

    Black Soldier Fly (Hermetia illucens) larvae-meal as an example for a new feed ingredients’ class in aquaculture diets

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    Regarding the growing demand for fishmeal, soybean meal and other feed ingredients in livestock feeding and especially in aquaculture, alternative protein carriers are an increasing concern of the animal feed industry. Beside the possibility to use animal by-products of non-ruminant origin, such as blood- and meat-meals in aquafeeds - according to the EU-regulation (EC) 56/2013 - the use of insect-based feed ingredients is progressively discussed among fish-feed producers, scientists and policy makers.Thus the possibility of mass-rearing flies on organic substrates was rediscovered. The black soldier fly, BSF (Hermetia illucens) occurring in tropical and subtropical countries all over the world including the Mediterranean states and European countries north of the alps proved to be an ideal candidate (Bondary et al. 1981; St-Hilaire et al. 2007 ). This organism can be reared on a wide range of organic (waste)-material which is currently deposited or burned or used in biogas plants in the best case. The developing stages of the fly can use the potential of this waste-material and reduce the volume of those substrates by up to 50%, producing biomass with a protein content of about 42% and a fat content of up to 35 % (Sheppard et al., 1994, Stamer et al. 2007). The suitability of the Hermetia pre-pupae meal as a protein source in feedstuff had been proven in poultry and pigs and also in warm water fish species (i.e. channel catfish and tilapia) (Bondari, Sheppard, 1981; Hale, 1973; Newton et al., 1977). For carnivorous cold water fish species (e.g. Salmonidae, Scophthalmidae) only limited data is available regarding the use of insect meals instead of fish meal (Kroeckel et al. 2012; St-Hilaire et al. 2007). The present study shows results of a feeding-trial on rainbow trout (Oncorhynchus mykiss) fed with two BSF-larvae meal containing diets

    Fostering Research Integrity through Institutional Policies: The Case of a Selected Institution of Higher Education1

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    Truth, trust and integrity are essential to research at higher education institutions. These institutions have accordingly adopted several policies tofoster research integrity. This article explores the likelihood that relevant policies at a selected institution of higher education foster research integrity. The qualitative, single exploratory case study commences with a review of scholarly literature and results in a conceptual model used for a directed content analysis of relevant institutional policies. The findings indicate that these policies do complement each other in fostering research integrity. Further research will be necessary to establish whether policies indeed contribute to responsible researcher conduct

    Wall-Fluid and Liquid-Gas Interfaces of Model Colloid-Polymer Mixtures by Simulation and Theory

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    We perform a study of the interfacial properties of a model suspension of hard sphere colloids with diameter σc\sigma_c and non-adsorbing ideal polymer coils with diameter σp\sigma_p. For the mixture in contact with a planar hard wall, we obtain from simulations the wall-fluid interfacial free energy, γwf\gamma_{wf}, for size ratios q=σp/σc=0.6q=\sigma_p/\sigma_c=0.6 and 1, using thermodynamic integration, and study the (excess) adsorption of colloids, Γc\Gamma_c, and of polymers, Γp\Gamma_p, at the hard wall. The interfacial tension of the free liquid-gas interface, γlg\gamma_{lg}, is obtained following three different routes in simulations: i) from studying the system size dependence of the interfacial width according to the predictions of capillary wave theory, ii) from the probability distribution of the colloid density at coexistence in the grand canonical ensemble, and iii) for statepoints where the colloidal liquid wets the wall completely, from Young's equation relating γlg\gamma_{lg} to the difference of wall-liquid and wall-gas interfacial tensions, γwlγwg\gamma_{wl}-\gamma_{wg}. In addition, we calculate γwf,Γc\gamma_{wf}, \Gamma_c, and Γp\Gamma_p using density functional theory and a scaled particle theory based on free volume theory. Good agreement is found between the simulation results and those from density functional theory, while the results from scaled particle theory quantitatively deviate but reproduce some essential features. Simulation results for γlg\gamma_{lg} obtained from the three different routes are all in good agreement. Density functional theory predicts γlg\gamma_{lg} with good accuracy for high polymer reservoir packing fractions, but yields deviations from the simulation results close to the critical point.Comment: 23 pages, 10 figures, REVTEX. Fig 5a changed. Final versio
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