The long-term effect of radio sources on the ICM

We have performed 3D hydrodynamical simulations of FR-II radio sources in beta-profile cooling-flow clusters. The effects of cooling of the cluster gas were incorporated into a modified version of the ZEUS-MP code. The simulations followed not only the active phase of the radio source, but also the long term behaviour for up to 2 Gyr after the jets of the radio source were switched off. We find as expected that the radio source has a significant effect on the cooling flow while it is active, however we also find that the effects of the radio source on the cluster are long-lived. A buoyancy driven convective flow is established as the remnants of the radio source rise through the cluster dragging material from the cluster core. Although the central Mpc of the cluster reverts to having a cooling flow, this asymmetric convective flow is able to remove the cool gas accumulating at the cluster core and indeed there is a net outflow persisting for timescales of about an order of magnitude longer than the time for which the source is active or longer. The convective flow may also provide a mechanism to enhance the metallicity of the cluster gas at large cluster radii.Comment: 7 pages, 13 figures; minor addition

A phenomenological study into the experience of their sexuality by males with spinal cord injury: research

On reviewing the literature on spinal cord injury (SCI) and sexuality in males, there was found to be a plethora of research in physical domains. Sadly, the psychological aspect of sexuality for men who experience SCI has been largely neglected. For this reason a phenomenological study was conducted to understand the experience of sexuality in its totality for the male who experiences SCI. Four males with SCI were included in the study. Central themes that emerged from the transcribed interviews included the establishment of an existential baseline, diminished independence and perceptions of masculinity post-injury. Participants also divulged needs pertaining to their (potential) relationships. Lastly, religion and certain coping mechanisms were found to either facilitate or hinder sexuality post-trauma depending on their rigidity and effectiveness respectively. Die studie van literatuur oor rugmurgbesering (RMB) en seksualiteit by mans, het 'n magdom navorsing oor die fisieke aspekte opgelewer. Ongelukkig is die sielkundige aspekte rondom seksualiteit by mans met RMB grootliks afgeskeep. Derhalwe is 'n fenomenologiese studie onderneem ten einde die man met RMB se ervaring van seksualiteit in sy geheel te ondersoek. Onderhoude is met vier mans wat RMB het gevoer. Sentrale temas wat uit die onderhoude voortvloei, sluit die vasstel van 'n eksistensi?le basislyn in, asook verminderde onafhanklikheid en veranderde beskouings oor manlikheid na die besering. Deelnemers het ook hulle behoeftes met betrekking tot hulle (potensi?le) verhoudings aangedui. Laastens is daar gevind dat godsdiens en sekere hanteringsmeganismes 'n positiewe of negatiewe impak kan h? op seksualiteit, afhangend van die rigiditeit en effektiwiteit daarvan. Keywords: Spinal cord injury, Sexuality, Males, Phenomenology, Experience (Health SA Gesondheid: interdisciplinary research journal: 2003 8(4): 3-11

The Place And Role Of Em-learning In Multi-mode Delivery Of Educator Training In South Africa

In any country in the world, the business and responsibility of, as well as the challenge to the education fraternity are to provide quality education to all. Therefore, quality teaching and learning should be provided to assist all learners to acquire the required competencies (knowledge, skills and attitudes) at the highest possible level in order to fulfil their respective and diverse roles in life (Steyn, Steyn, De Waal and Wolhuter, 2002: 34). The point of departure should be to provide quality education in such a way that it is accessible and affordable to all. The quality of education is to a large extent determined by the quality of information transfer and the quality and quantity of support that the learners receive to master the outcomes of their studies. The developments in the field of Information and Communication Technology (ICT) provide a real opportunity to improve the quality of information transfer and teaching support that learners can obtain. However, the real challenge for education in the developing world, and even in the developed world, is the level of accessibility, affordability and complexities of ICT (Dreyer, 2005: 4). The result of the ability to provide assessable ICT in developing countries is the ever-increasing digital gap that deeply influences the quality of education of less affluent people and the difference in quality of education between developed and developing countries. At the North-West University, Faculty of Education Sciences, the decision was made to provide enriched teaching and learning to a particular group of teachers via an off-campus blended teaching and learning strategy. Within the limitations of affordability and access, the decision was made to use the multi-mode teaching strategy (including some types of modern ICT) to support the students and to enhance the support that the learners obtain. The aim of this article is to report on the reasons, development and implementation of the project as well as initial results. Attention will be given to the nature and contents of the ADP-programme, the theoretical framework that was used to develop the strategy and the nature and content of the multi-mode teaching strategy that was employed. The method of research that was used to develop the teaching and learning strategy particularly applicable to this programme was that of a process of iterative and systematic critical reasoning. Based on the critical reasoning, it was through an combined (and not necessarily initially decided upon) application of several (applicable) scientific methods and processes, such as observation, analysis and synthesis, induction and deduction that the strategy was developed (Stoker, 1961: 62-90; Mouton and Marais, 1989: 102; Mouton, 1996; 77-78; Harden and Thomas, 2005: 258; Bensley, 1998: 3; Ennis, 1987: 9).Faculty of Education Sciences North-West Universit

Magnetic fields in galaxies: I. Radio disks in local late-type galaxies

We develop an analytical model to follow the cosmological evolution of magnetic fields in disk galaxies. Our assumption is that fields are amplified from a small seed field via magnetohydrodynamical (MHD) turbulence. We further assume that this process is fast compared to other relevant timescales, and occurs principally in the cold disk gas. We follow the turbulent energy density using the Shabala & Alexander (2009) galaxy formation and evolution model. Three processes are important to the turbulent energy budget: infall of cool gas onto the disk and supernova feedback increase the turbulence; while star formation removes gas and hence turbulent energy from the cold gas. Finally, we assume that field energy is continuously transferred from the incoherent random field into an ordered field by differential galactic rotation. Model predictions are compared with observations of local late type galaxies by Fitt & Alexander (1993) and Shabala et al. (2008). The model reproduces observed magnetic field strengths and luminosities in low and intermediate-mass galaxies. These quantities are overpredicted in the most massive hosts, suggesting that inclusion of gas ejection by powerful AGNs is necessary in order to quench gas cooling and reconcile the predicted and observed magnetic field strengths.Comment: 10 pages, 8 figures; MNRAS in pres

AGN effect on cooling flow dynamics

We analyzed the feedback of AGN jets on cooling flow clusters using three-dimensional AMR hydrodynamic simulations. We studied the interaction of the jet with the intracluster medium and creation of low X-ray emission cavities (Bubbles) in cluster plasma. The distribution of energy input by the jet into the system was quantified in its different forms, i.e. internal, kinetic and potential. We find that the energy associated with the bubbles, (pV + gamma pV/(gamma-1)), accounts for less than 10 percent of the jet energy.Comment: "Accepted for publication in Astrophysics & Space Science

Tbx5 is Required for Avian and Mammalian Epicardial Formation and Coronary Vasculogenesis.

Rationale: Holt-Oram syndrome (HOS) is an autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene. Overexpression of Tbx5 in the chick proepicardial organ (PEO) impaired coronary blood vessel formation. However, the potential activity of Tbx5 in the epicardium itself, and Tbx5\u27s role in mammalian coronary vasculogenesis, remains largely unknown. Objective: To evaluate the consequences of altered Tbx5 gene dosage during PEO and epicardial development in the embryonic chick and mouse. Methods and Results: Retroviral-mediated knockdown or upregulation of Tbx5 expression in the embryonic chick PEO as well as proepicardial-specific deletion of Tbx5 in the embryonic mouse (Tbx5(epi-/-)) impaired normal PEO cell development, inhibited epicardial and coronary blood vessel formation and altered developmental gene expression. The generation of epicardial-derived cells (EPDCs) and their migration into the myocardium was impaired between embryonic day (E) 13.5-15.5 in mutant hearts due to delayed epicardial attachment to the myocardium and subepicardial accumulation of EPDCs. This caused defective coronary vasculogenesis associated with impaired vascular smooth muscle cell recruitment, and reduced invasion of cardiac fibroblasts and endothelial cells into myocardium. In contrast to wildtype hearts that exhibited an elaborate ventricular vascular network, Tbx5(epi-/-) hearts displayed a marked decrease in vascular density that was associated with myocardial hypoxia as exemplified by HIF1α upregulation and increased binding of Hypoxyprobe-1. Tbx5(epi-/-) mice with such myocardial hypoxia exhibited reduced exercise capacity compared to wildtype mice. Conclusions: Our findings support a conserved Tbx5 dose-dependent requirement for both proepicardial and epicardial progenitor cell development in chick and mouse coronary vascular formation

An outbreak of contagious bovine pleuropneumonia in the Owambo Mangetti area of South West Africa/Namibia : microbiological, immunofluorescent, pathological and serological findings

An outbreak of contagious bovine pleuropneumonia (CBPP) in the Owambo Mangetti area of South West Africa/Namibia in 1982 led to the slaughter of 3 153 cattle. The lungs of 266 of these animals were scrutinized for gross lesions of CBPP and samples of lung tissue, sequestral contents or pleural fluid were submitted to the Veterinary Research Institute (VRI), Onderstepoort for microbiological, immunofluorescent and pathological examination. Immunofluorescence proved to be the most successful method of diagnosis producing 96 % of positives, while mycoplasma isolations were only positive in 64 % of the 55 specimens processed in parallel. This clearly demonstrated the value of the former technique in the accurate as well as rapid diagnosis of CBPP. The impression smear technique employed, using Eriochrome black counterstaining proved most satisfactory and easy to interpret. The isolation of M. mycoides was influenced by the transit times and temperature of the samples on arrival at the VRI. No pathogenic bacteria were found in routine aerobic bacterial cultures from 27 of the samples submitted. Complement fixing antibodies were present in the sera of 16 cattle and titres varied between 10 and 320. Animals in which antibodies were absent included those with early lung lesions and some with sequestra.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

Oh Comrade, What Times those Were! History, Capital Punishment and the Urban Square.

From the perspective of traditional Western histories of the urban realm, public squares have been seen to represent a privileged site of urban containment expressive of a community's highest values of individual freedom, social inclusion and cultural refinement. But such views can be misleading. For what is omitted from the scope of these conventional historical visions and their ideal and conforming subjects of public spatial discourse, is an entire array of other and darker narratives that equally speak of personal choice, collective participation and cultural value. Capital punishment reflects such an example, a practice that once comprised an integral part of the political, social and cultural landscape of a Western city's squares and streets. Drawing from Michel Foucault's Discipline and Punish and its implications on how we might begin to re-read the history of the urban square, the following seeks to explore those practices and modes of rationality that underpinned the once public spectacle of executions and torture as a vital condition of urban life. In particular, this discussion will question the assumptions of an historical tradition that continues to reduce our understanding of the city and its open spaces of public appearance and action to an idealistic and illusory reality of the urban realm and its narrow framing of collective conduct, necessity and significance

Response assessment in lymphoma with PET/CT

No abstact available