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<p>Stars form in clusters amidst complex and coupled physical phenomena. Among the most important of these is radiative feedback, which heats the surrounding gas to suppress the formation of many low-mass stars. In simulations of star formation, pre-main-sequence modeling has often been neglected and stars are assumed to have the radii and luminosities of zero-age main sequence stars. We challenge this approach by developing and integrating a one-zone protostellar evolution model for FLASH and using it to regulate the radiation output of forming stars. The impact of accurate pre-main-sequence models is less ionizing radiation and less heating during the early stages of star formation. For stars modeled in isolation, the effect of protostellar modeling resulted in ultracompact HII regions that formed slower than in the ZAMS case, but also responded to transitions in the star itself. The HII region was seen to collapse and subsequently be rebuilt as the star underwent a swelling of its radius in response to changes in stellar structure and nuclear burning. This is an important effect that has been missed in previous simulations. It implies that observed variations in HII regions may signal changes in the stars themselves, if these variation can be disentangled from other environmental effects seen in the chaotic cluster environment.</p> / Master of Science (MSc)

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Kalzium ist ein wichtiger intrazelluläre Botenstoff, der extrazelluläre Signale in zelluläre Antworten übersetzt. Oft werden externen Signale in wiederholte Anstiege der zytosolischen Kalziumkonzentration übersetzt, die als Oszillationen bezeichnet werden. Diese interdisziplinäre Arbeit kombiniert biologische Experimente, analytische Methoden der theoretischen Physik und Computersimulationen, um den Oszillationsmechanismus zu charakterisieren. Von wesentlicher Bedeutung ist dabei die räumlich inhomogene Verteilung der Kanäle, die Kanalcluster bilden. Dies induziert zusammen mit Pumpen große Konzentrationsgradienten in der Nähe von offenen Clustern, was zu einer hierarchischen Organisation führt. Unter diesem Gesichtspunkt erwartet man, dass Kalziumoszillationen stochastisch sind und auf räumlicher Wechselwirkung beruhen. Diese Hypothese wird im ersten Teil der Arbeit experimentell verifiziert, indem Oszillationen vier verschiedener Zellarten analysiert werden. Der Kalziumsignalweg nutzt thermisches Rauschen konstruktiv um globale Signale zu bilden. Dabei werden molekulare Fluktuationen durch die hierarchische Struktur auf die zelluläre Ebene gehoben. Dies steht im Gegensatz zu der jahrzehntelang weitläufigen Auffassung, dass Kalzium ein repräsentatives Beispiel eines zellulären Oszillators ist. Des weiteren macht dieses Ergebnis Kalzium zu einem ersten natürlichen Beispiel für "array enhanced coherent resonance". Im Modellierungsteil dieser Arbeit wird ein physiologisches Modell für die intrazelluläre Kalziumdynamik entwickelt, das die dreidimensionale Struktur von Zellen berücksichtigt. Es verwendet ein detailliertes Kanalmodell und berücksichtigt sowohl Diffusion als auch Reaktionen mit Puffern. Der entwickelte parallele Green''s cell Algorithmus generiert in Abhängigkeit von physiologischen Parametern das gesamte Spektrum der experimentell bekannten Kalziumsignale und spiegelt die experimentellen Daten des ersten Teils in nahezu perfekter Weise wider. / Calcium is an important second messenger in cells serving as a critical link between extracellular stimuli and their cellular responses. The external signals are translated often into repeated increases of the cytosolic calcium concentration what is referred as oscillations. This work uses an interdisciplinary approach combining experimental techniques from biology, analytical tools from theoretical physics and computer simulations to clarify the question of the oscillation mechanism and how cells can generate globally coordinated calcium signals originated from local stochastic channel dynamics. In this context, the spatial inhomogeneous distribution of channels forming channel clusters plays a key role. Together with calcium pumps and buffers, this induces huge functional concentration gradients close to open clusters, leading to a hierarchical organization of calcium signals. Thus, calcium oscillations are predicted to be stochastic and to have a spatial character. This hypothesis is justified experimentally in the first part of this thesis by analyzing calcium oscillations of four different cell types. Hence, calcium signaling constructively uses thermal noise to build global signals. This contradicts the current opinion of the last decades of calcium being a representative cellular oscillator. Moreover, this makes calcium a first natural example of array enhanced coherent resonance. In the modeling part of this work, a physiological model for intracellular calcium dynamics in three spatial dimensions is developed that takes the spatial arrangement of cells seriously. It uses a detailed channel model for the discrete release sites and takes into account diffusion and buffer interaction of calcium. In dependence on physiologic parameters, the developed parallel Green''s cell algorithm generates in a natural way the whole spectrum of experimentally known calcium signals and fits the experimental data of the first part in an almost perfect manner.

This critical exploratory study investigates the perceptions and practices of Norwegian lecturers on the implementation of a policy of English as a Medium of Instruction (EMI) at their Higher Education Institution (HEI). It focuses on their attitudes towards English usage, how they have been prepared and cope in the classroom, and looks at their language and pedagogic competences. The socio-cultural context of using English inside and outside the auditorium is explored and leads to questions of Anglo/American influence and Norwegian domain loss. The study is informed by critical Applied Linguistics (CALx), linguistic imperialism and Bourdieu’s theories on social capital and power. It examines teaching through critical pedagogy and Vygotsky’s socio-cultural theory of learning to aid understanding of classroom engagement and communication, and successful learning. This study has been informed by the critical approach to challenge normative assumptions of the use of EMI. Qualitative methods were used to collect data; twenty Norwegian teaching academics were interviewed, of whom five were observed whilst teaching. Careful coding and analysis of the data revealed surprising attitudes and perceptions varying from enthusiasm to anxiety for EMI. The participants generally accepted the top-down decision making by the administration on the increase of EMI and English usage. The influences of globalisation and commodification at HEIs combined with the rapid increase in English usage seem to have led to increased power of the management and bureaucratization. Some participants, mostly from the humanities, felt they lacked voice and agency in the implementation and their preparation for EMI, whilst some from the sciences actively embraced English and some wanted English as the working language in HEIs. There was a general feeling that more time and language resources were needed for professional development to cope with the change to EMI. All the participants worked hard to succeed in EMI; they were aiming at NS language competencies and wanted to be better at grammar, pronunciation and terminology, but seemed unaware of the pragmatic level of communication required for teaching and did not recognise the necessity of pedagogic training for EMI. There was a lack of dialogic teaching making co-constructed learning challenging and transformative pedagogy more difficult to achieve. They adapted to the multi-cultural/lingual classroom in a pragmatic manner, but were not given spaces for counter-pedagogies, critical pedagogy and the ideals of the transformative intellectual. The research reveals five areas of concern: a) inadequate English language at the pragmatic level for the demands of EMI, b) inadequate pedagogic skills for the multi-lingual and cultural classroom, c) concern over local and international students’ level of English, d) standardized, Anglo/American teaching materials leading to a lack of diversity and critical approaches, and e) the threat to academic Norwegian from international academics not learning Norwegian, the publishing reward system at Norwegian HEIs and the perceived status of English, and the resultant decline in dissemination to the general public. However juxtaposed to the above points, most participants experienced the international classroom positively and were well-received by and pleased to be in their academic Community of Practice resulting generally in an ambivalent attitude to EMI.

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Family businesses have unique dynamics and success stories but at the same time face unique challenges. Intergenerational small and medium-sized family businesses in South Africa play an increasingly important role in creating jobs together with wealth distribution. This study attempts to explore the complicated relationship and inimitable characteristics of family business surroundings against the added challenges of family business perceived success and family business continuity. Notwithstanding family businesses being a prevalent phenomenon in the economies of most countries, insight into this form of enterprise is still limited. Topics such as commitment, entrepreneurial orientation, job satisfaction, satisfaction with life and perceived success of the family business, among others, were investigated. In order to achieve the primary objective of this study, a survey was undertaken using a structured questionnaire. The reliability of the questionnaire was determined by calculating the Cronbach alpha coefficient, which indicated that the questionnaire used in this study conformed to the criteria of acceptable reliability and can be regarded as internally consistent. The survey yielded 143 usable questionnaires from 42 family businesses restricted to Gauteng province and the North West province in South Africa. The nature of this study was investigative and descriptive statistics was therefore used to analyse the statements of all the participating respondents. The selected determinants influencing the perceived success of small and medium-sized family business was then measured and regressional analyses were further conducted. Conclusions were drawn from this study on the outcomes of the selected factors influencing the perceived success of small and medium-sized family business. Finally, a critical evaluation was done and practical recommendations are suggested to improve family business wellness and, subsequently, increase the sustainability of such business. / MBA, North-West University, Potchefstroom Campus, 2015

The primary objective of the study was to determine the business success factors for the second-hand motor vehicle industry in the Vaal Triangle. This kind of study has never been conducted before within the Vaal Triangle and it is therefore intended to contribute to the body of knowledge within the field of entrepreneurship. A questionnaire was designed and distributed to dealerships within the Vaal Triangle region, and it was administered by the researcher. There are one hundred and twenty three (123) dealerships in the Vaal Triangle and fifty eight (58) participated in the study. The demographics of the study revealed that males dominate car dealerships as compared to females, and also that Whites and Indians are the dominating races. Most participants are relatively young, i.e. less than 35 years and also the majority of dealerships are less than 15 years old. Furthermore, the study found that participants preferred starting a business from their pockets rather than going to the bank or government institutions such as IDC or NEF for funding. There was no significant difference in opinion between males and females. There were, however, medium to large differences in opinion between owner, manager and sales executive on some of the entrepreneurial constructs, for example, customer services and SME characteristics. The study concluded that business success factors for the second-hand car industry in the Vaal Triangle region are (ranked from highest to lowest): Entrepreneurial competences, Marketing of the dealership, Dealership location, Product and Customer services, Characteristics of the Small Medium Enterprise and lastly, Resources and funding of the business. Based on the results of the analysis and discussions, practical recommendations are made which will assist in improving the knowledge in the field of entrepreneurship within the car industry. / MBA (Business Administration), North-West University, Potchefstroom Campus, 2015

The objective of this study is to assess the role that succession planning plays in family businesses in the Sedibeng region of the Gauteng province in South Africa. According to Netsiande (2008:1) family businesses should anticipate, recognise, understand and work pro-actively on issues, learn from other businesses and find their own unique solution.to ensure sustainability. Management succession and succession planning is very important and it has a significant impact on family members, society and the business and economic sectors. This research study was conducted by means of a literature and empirical study. The aim of the literature studies was to gain insight into family businesses and the importance of succession planning. Topics covered in the literature study on family businesses includes a definition of family businesses, family business success, uniqueness of family businesses, characteristics of successful family businesses, advantages and disadvantages of family businesses, challenges facing family businesses. Topics covered in the literature study on succession planning includes a definition of succession, the importance of succession in family businesses, factors that influence succession, succession planning, selecting and choosing a successor as well as mentoring and preparation of the successor(s). The study was concluded on the basis of the findings of the empirical study, that the aspects that needs more attention to help with successful succession planning in family businesses in the Sedibeng district of the Gauteng province in South Africa, are the relationship between owner-manager and successor(s), willingness of the successor(s) to take over the business, willingness of the successor(s) to hand over the business and the preparation level of the successor(s). Lastly practical recommendations were suggested to support the family and the business to effectively manage succession planning in family businesses. / MBA (Business Administration), North-West University, Potchefstroom Campus, 2015

Family businesses have unique dynamics and success stories but at the same time face unique challenges. Intergenerational small and medium-sized family businesses in South Africa play an increasingly important role in creating jobs together with wealth distribution. This study attempts to explore the complicated relationship and inimitable characteristics of family business surroundings against the added challenges of family business perceived success and family business continuity. Notwithstanding family businesses being a prevalent phenomenon in the economies of most countries, insight into this form of enterprise is still limited. Topics such as commitment, entrepreneurial orientation, job satisfaction, satisfaction with life and perceived success of the family business, among others, were investigated. In order to achieve the primary objective of this study, a survey was undertaken using a structured questionnaire. The reliability of the questionnaire was determined by calculating the Cronbach alpha coefficient, which indicated that the questionnaire used in this study conformed to the criteria of acceptable reliability and can be regarded as internally consistent. The survey yielded 143 usable questionnaires from 42 family businesses restricted to Gauteng province and the North West province in South Africa. The nature of this study was investigative and descriptive statistics was therefore used to analyse the statements of all the participating respondents. The selected determinants influencing the perceived success of small and medium-sized family business was then measured and regressional analyses were further conducted. Conclusions were drawn from this study on the outcomes of the selected factors influencing the perceived success of small and medium-sized family business. Finally, a critical evaluation was done and practical recommendations are suggested to improve family business wellness and, subsequently, increase the sustainability of such business. / MBA, North-West University, Potchefstroom Campus, 2015