Unmanned spacecraft RTG shield optimization study Final report

Analytic procedures and computer codes for prediction of weight optimized radioisotope thermoelectric generator shields for unmanned spacecraf

Code CUGEL: A code to unfold Ge(Li) spectrometer polyenergetic gamma photon experimental distributions

A FORTRAN code was developed for the Univac 1108 digital computer to unfold lithium-drifted germanium semiconductor spectrometers, polyenergetic gamma photon experimental distributions. It was designed to analyze the combination continuous and monoenergetic gamma radiation field of radioisotope volumetric sources. The code generates the detector system response matrix function and applies it to monoenergetic spectral components discretely and to the continuum iteratively. It corrects for system drift, source decay, background, and detection efficiency. Results are presented in digital form for differential and integrated photon number and energy distributions, and for exposure dose

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

Mindfulness: A foothold for Rogers's humanistic person-centred approach

This article probed and contextualised the strong parallels between meditation derived mindfulness and Rogers's humanistic person-centred (PC) approach. This was done through a conceptual and evaluative literature review of the PC framework in relation to definitive descriptions of mindfulness. Elements of mindfulness within the core conditions of PC therapy were explored and verified. Quotations, pragmatic, behavioural descriptions and explications provided evidence of a shared ideology inherent in both concepts via “way of being”. The findings suggested that mindfulness cultivates, harmonises and deepens essential therapist qualities in PC therapy. This review article could supply a rationale for significant inferences in the implementation of meditation-inspired activities in the practical preparation of trainee therapists as well as optimising proficiency and refinement in professional practice

A continuum model for the dynamics of the phase transition from slow-wave sleep to REM sleep

Previous studies have shown that activated cortical states (awake and rapid eye-movement (REM) sleep), are associated with increased cholinergic input into the cerebral cortex. However, the mechanisms that underlie the detailed dynamics of the cortical transition from slow-wave to REM sleep have not been quantitatively modeled. How does the sequence of abrupt changes in the cortical dynamics (as detected in the electrocorticogram) result from the more gradual change in subcortical cholinergic input? We compare the output from a continuum model of cortical neuronal dynamics with experimentally-derived rat electrocorticogram data. The output from the computer model was consistent with experimental observations. In slow-wave sleep, 0.5–2-Hz oscillations arise from the cortex jumping between “up” and “down” states on the stationary-state manifold. As cholinergic input increases, the upper state undergoes a bifurcation to an 8-Hz oscillation. The coexistence of both oscillations is similar to that found in the intermediate stage of sleep of the rat. Further cholinergic input moves the trajectory to a point where the lower part of the manifold in not available, and thus the slow oscillation abruptly ceases (REM sleep). The model provides a natural basis to explain neuromodulator-induced changes in cortical activity, and indicates that a cortical phase change, rather than a brainstem “flip-flop”, may describe the transition from slow-wave sleep to REM

A code to unfold scintillation spectrometer polyenergetic gamma photon experimental distributions

FORTRAN code to unfold sodium iodide scintillation spectrometer polyenergetic gamma photon experimental distribution

What can a mean-field model tell us about the dynamics of the cortex?

In this chapter we examine the dynamical behavior of a spatially homogeneous two-dimensional model of the cortex that incorporates membrane potential, synaptic flux rates and long- and short-range synaptic input, in two spatial dimensions, using parameter sets broadly realistic of humans and rats. When synaptic dynamics are included, the steady states may not be stable. The bifurcation structure for the spatially symmetric case is explored, identifying the positions of saddle–node and sub- and supercritical Hopf instabilities. We go beyond consideration of small-amplitude perturbations to look at nonlinear dynamics. Spatially-symmetric (breathing mode) limit cycles are described, as well as the response to spatially-localized impulses. When close to Hopf and saddle–node bifurcations, such impulses can cause traveling waves with similarities to the slow oscillation of slow-wave sleep. Spiral waves can also be induced. We compare model dynamics with the known behavior of the cortex during natural and anesthetic-induced sleep, commenting on the physiological significance of the limit cycles and impulse responses

Cardiogenic shock – a look at acute functional mitral incompetence

A 44-year-old man presented with cardiogenic shock secondary to acute functional mitral incompetence as well as septic shock related to pneumonia. The patient  deteriorated haemodynamically despite adequate medical therapy. An echocardiogram revealed a massive mitral incompetence and an ejection fraction of 32%. An intra-aortic balloon pump was placed and the patient improved dramatically. On day 6 after admission the echocardiogram was repeated, revealing a mild mitral incompetence and an ejection fraction of 58%

Vryheid en gebondenheid in die ekonomie van die Republiek van Suid-Afrika

Toe ek ingewillig het om u toe te spreek oor „Vryheid en gebondenheid in die Ekonomie van die Republiek van Suid- Afrika” het ek nie besef dat dit ’n onderwerp is wat veel meer diepgaande studie vereis as waartoe iemand wat tot ’n groot mate die kantoor en studeerkamer verruil het vir die plaas in staat is nie. Ek is dus bevrees dat ek nie reg sal kan laat geskied aan so ’n belangrike onderwerp nie en u hoë verwagtings waarskynlik sal teleurstel

Minimum vereistes vir 'n Suid-Afrikaanse onderwysstelsel: 'n Nederlands-Belgiese perspektief1

A common element among the different educational interest groups in South Africa is the expectation that a new education system should be acceptable to the international community. This expectation could therefore serve as one of the determinants that might guide the development of an education system that could serve the educational needs of a majority of interest groups. This article is the result of qualitative research by means of which the opinions of Belgian and Dutch communities were identified. These opinions regarding the education system policy, education system administration, school system and supportive services of the South African education system, can also be viewed as an exponent of the opinion of the international community