Thesis (MScAgric)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (Ph. D.)--Columbia University, 1934. / Vita. Bibliography: p. 26.

Thesis (M.S.) in Plant, Soil and Environmental Sciences--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 79-84).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Abstracted in Dissertation abstracts, v. 25 (1965) no. 7, p. 3831-2. Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Les étoiles massives sont les principaux contributeurs à l'enrichissement du milieu interstellaire. Ce sont généralement des rotateurs rapides, dotés d'une enveloppe radiative dans laquelle l'interaction de la stratification et la rotation génère une rotation différentielle. Celle-ci peut alimenter divers phénomènes de transport et l'évolution rapide de l'étoile. Nombre de ces étoiles sont par ailleurs des pulsateurs classiques. Cette thèse s'intéresse en premier lieu à l'interaction entre la rotation différentielle et les pulsations à basse fréquence dans l'étoile : celles-ci sont des modes gravito-inertiels dont la force de rappel est une combinaison de la force de Coriolis et de la poussée d'Archimède. Ils sondent les couches profondes de l'étoile, et sont étudiés suivant deux méthodes : dans la limite non-dissipative par la méthode des caractéristiques, et dans le cas dissipatif par la résolution du problème complet par une méthode spectrale. Nous mettons en évidence différentes singularités (attracteurs, latitudes critiques, résonances de corotation, piégeage en coin) et des modes réguliers. Certains modes sont excités par des instabilités baroclines, qui, si des effets non-linéaires provoquent leur saturation, permettent l'existence d'un mécanisme d'excitation nouveau dû à la rotation différentielle. Dans un second temps, nous avons associé le code de structure ESTER au code de calcul d'oscillations TOP. Ces deux codes calculent les quantités dans une étoile en deux dimensions et les modes associés en tenant compte des effets de la rotation de façon complète. Nous utilisons visibilités et taux d'amortissement des modes pour sélectionner dans le spectre synthétique les meilleurs candidats à l'identification des modes observés. Nous présentons une application au rotateur rapide Rasalhague (aOph), pour lequel de nombreuses observations sont disponibles. Nous n'avons pas obtenu une identification des modes univoque, mais le problème est maintenant mieux cerné et diverses pistes de progrès ont été identifiées. / Massive stars are the main contributors of the interstellar medium enrichment. These stars are usually fast rotators, with a radiative envelope in which the interaction between stratification and rotation gives rise to a differential rotation. This can trigger transport phenomena in the star, and affect its fast evolution. Besides, many of these stars are classical pulsators. This work focuses first on the impact of a differential rotation on the low-frequency oscillation spectrum which contains gravito-inertial modes. These modes are restored by the combination of buoyancy and Coriolis force and probe deep layers of stars. Our study is twofold : we compute the paths of characteristics in the non-dissipative limit, and solve the fully-dissipative eigenvalue problem numerically using a spectral decomposition. We find various singularities (attractors, critical latitudes, corotation resonances, wedge-trapping) and regular modes. Some of these modes are excited by baroclinic instabilities that may saturate through non-linear effects. If so, we have discovered a new excitation mechanism for these modes, driven by differential rotation. Aside of this theoretical work ; we have considered the case of Rasalhague (aOph), which is a well-known fast rotator. We studied this star by associating the ESTER structure code with the TOP oscillation code. Both of these codes use a two-dimensional structure, taking rotation effects fully into account. We use the mode damping rates and visibilities to filter the best candidates for observed modes identification out of the synthetic spectra. Even though we could not reach a satisfactory identification of the observed frequencies, we improved our understanding of the problem and identified the next steps to be taken.

No description available.

Weens die unieke eiesoortigheid van die mens is sy behoeftes vanselfsprekend uiters divers. Wat vir die een persoon prioriteit is, mag vir sy buurman geensins belangrik wees nie. Dit is egter ook ’n gegewe, dat die mens heelwat gemeenskaplike ervarings, emosies en behoeftes deel. Een hiervan is die behoefte wat hy het om te weet dat die besluit wat hy gaan of wil neem die regte een binne die konteks van sy keuse mag wees. Die woord ‘behoefte’ kan waarskynlik in hierdie geval vervang word met die begrip ‘genade’. Sonder om 'n platvorm vir debat te skep, word die stelling gehandhaaf dat ‘genade’ slegs van die Skepper afkomstig is. Met hierdie stelling as agtergrond was dit 'n minder aangename ervaring om vir feitlik twintig jaar te moes toekyk hoe koringboere hul besluite, veral met betrekking tot die samestelling van wisselboustelsels, moes neem, klaarblyklik in totale gebrek aan die gawe van ‘genade’. Nodeloos om te sê, met gepaardgaande negatiewe gevolge. Die meer gemaklike verontskuldiging is om te redeneer dat ons Skepper relatief suinig is met die uitdeel van sy ‘genade’. Alvorens die begrip van Prediker 10:10 nog nie ten volle begryp is nie, kan so 'n stelling dalk makliker gemaak word. Hierdie gedeelte uit die Skrif sê in werklikheid die teenoorgestelde – dat God baie vrygewig is met Sy ‘genade’, maar dat die mens sy gesonde verstand moet gebruik om dit ten volle te benut. Die wens is dat hierdie studie, 'n deel sal uitmaak van die proses om die byl skerp te maak om sodoende die houtkap-proses effektief uit te voer.

The collapse of Enron and several other companies, such as Global Crossing and the more recent scandal of Tesco, raised concerns worldwide about auditor independence and audit quality. The scandals have proven that particularly the joint-provision of auditing and nonaudit services (NAS) along with a long-term auditor-client relationship tend to adversely impact auditor independence thus audit quality, triggering the need for a new regulation. In order to solve this problem, the European Union implemented a new regulation requiring public listed entities (PIEs), which are defined as listed companies, credit institutions and insurance undertakings, to rotate their audit firm after a period of 10 financial years. The primary purpose of my master thesis is to gain a deeper understanding of audit firms’ and public listed firms’ perceptions of auditor rotation, meant in the sense of audit firm rotation, and its impact on audit quality. More specifically, I aim to investigate whether audit firm rotation enhances audit quality due to a fresh view brought to the company audited by a new auditor or lowers it because of a new auditor’s lack of knowledge about the client’s industry. Current literature regarding the new EU regulation, audit firm rotation and its impact on audit quality as well as the early stage of implementation of the new EU Directive in Sweden helped me to recognize a research gap. Existing studies similar to mine have not been concerned with getting a deeper understanding about the perception of this topic by audit companies and public listed companies located in Sweden. The research philosophy of my study is based on the constructivist ontological view and interpretivist epistemological perspective. In addition, the deductive approach is used to study the research question, while applying the qualitative research method by carrying out multiple semi-structured interviews with auditors and CEOs (Chief Executive Officers) and CFOs (Chief Financial Officers) of public listed companies based in Sweden. The final results are gained through the combination of primary data gathered from the interviews, and secondary data collected during my literature search. My findings demonstrate that the auditors asked are in favour of audit partner rotation since according to their opinion it positively impacts audit quality because of the prevention of a too close relationship between auditor and client. Nevertheless, they do not see an additional advantage from audit firm rotation as they believe that audit partner rotation has already fulfilled the same purpose. CEOs and CFOs of public listed companies have diverse views regarding this topic. Three from five perceive auditor rotation is increasing audit quality due to the fresh look brought by a new auditor and enhanced auditor independence, while the two others think that the new regulation is reducing audit quality caused by the new auditor´s lack of industry knowledge of the client. Other factors positive influencing audit quality are the separation of NAS and audit, joint-audits, expertise and experience of the auditor, a detailed audit plan, providing of full information by the client and the appointment of the auditor by the client itself. Keywords: auditor rotation, audit firm rotation, EU regulation 2016, audit quality, long-term auditor-client relationship, auditing in Sweden, International Standards on Auditing (ISA), role of auditor, audit firm size, non-audit services and auditor independence.

Using Maxwell's equations of electrodynamics and the linearized fundamental equation of hydrodynamics neglecting all but the ponderomotive force, the two differential equations characterizing toroidal and poloidal modes of oscillations are obtained. Neglecting the coupling between these modes the toroidal mode which appears to be connected with the phenomenon of geomagnetic micropulsations is studied in detail. Substituting for the constant magnetic field the undeformed dipole field of the Earth the eigenperiods of the oscillating lines of force are computed assuming a constant charge density distribution. Using numerical methods the eigenperiods are also obtained in the case of a variable charge density. Since the Earth's dipole field is presumably deformed by the solar wind a compressed dipole field is introduced into the equation of toroidal oscillations. The eigenperiods of the oscillating lines of force are obtained in this case, assuming a constant charge density distribution. For the case of a variable charge density a numerical method is described which could yield the eigenperiods. / Science, Faculty of / Physics and Astronomy, Department of / Graduate