En dépit de progrès croissants durant la dernière décennie, la complexité des écosystèmes marins est encore imparfaitement simulée par les modèles.Les formulations des processus biogéochimiques sont en général établies de manière empirique et contraintes par une multitude de paramètres.Il est ainsi généralement admis que leurs incertitudes impactent fortement l'estimation de la production primaire, dont le rôle dans le cycle du carbone est primordial.Analyser les impacts de l'incertitude des modèles est donc nécessaire pour améliorer la représentation des caractéristiques biogéochimiques de l'océan.Dans le contexte d'assimilation de données de la couleur de l'océan, la définition des erreurs de prévision représente de plus un important verrou aux performances des systèmes.Ces points seront analysés dans cette thèse. L'objectif sera d'examiner, dans un contexte de modélisation/assimilation, la pertinence d'utiliser une approche probabiliste basée sur une simulation explicite des incertitudes biogéochimiques du modèle couplé au 1/4° NEMO/PISCES sur l'océan Atlantique Nord.A partir d'une simulation déterministe du modèle PISCES, nous proposerons une méthode pour générer des processus aléatoires, AR(1), permettant d'inclure des structures spatiales et temporelles de corrélations.A chaque pas de temps, ces perturbations aléatoires seront ensuite introduites dans le modèle par l'intermédiaire de paramétrisations stochastiques.Elles simuleront 2 différentes classes d'incertitudes: les incertitudes sur les paramètres biogéochimiques du modèle et les incertitudes dues aux échelles non résolues dans le cas d'équations non linéaires. L'utilisation de paramétrisations stochastiques permettra ainsi d'élaborer une version probabiliste du modèle PISCES, à partir de laquelle nous pourrons réaliser une simulation d'ensemble de 60 membres.La pertinence de cette simulation d'ensemble sera évaluée par comparaison avec les observations de la couleur de l'océan SeaWIFS. Nous montrerons en particulier que la simulation d'ensemble conserve les structures de grande échelle présentes dans la simulation déterministe.En utilisant les distributions de probabilité définies par les membres de l'ensemble, nous montrerons que l'ensemble capture l'information des observations avec une bonne estimation de leurs statistiques d'erreur (fiabilité statistique). L'intérêt de l'approche probabiliste sera ainsi d'abord évalué dans un contexte de modélisation biogéochimique. / In spite of recent advances, biogeochemical models are still unable to represent the full complexity of marine ecosystems.Since mathematical formulations are still based on empirical laws involving many parameters, it is now well established that the uncertainties inherent to the biogeochemical complexity strongly impact the model response.Improving model representation therefore requires to properly describe model uncertainties and their consequences.Moreover, in the context of ocean color data assimilation, one of the major issue rely on our ability to characterize the model uncertainty (or equivalently the model error) in order to maximize the efficiency of the assimilation system.This is exactly the purpose of this PhD which investigates the potential of using random processes to simulate some biogeochemical uncertaintiesof the 1/4° coupled physical–biogeochemical NEMO/PISCES model of the North Atlantic ocean.Starting from a deterministic simulation performed with the original PISCES formulation, we propose a genericmethod based on AR(1) random processes to generate perturbations with temporal and spatial correlations.These perturbations are introduced into the model formulations to simulate 2 classes of uncertainties: theuncertainties on biogeochemical parameters and the uncertainties induced by unresolved scales in the presenceof non-linear processes. Using these stochastic parameterizations, a probabilistic version of PISCES is designedand a 60-member ensemble simulation is performed.The implications of this probabilistic approach is assessed using the information of the probability distributions given of this ensemble simulationThe relevance and the impacts of the stochastic parameterizations are assessed from a comparison with SeaWIFS satellite data.In particular, it is shown that the ensemble simulation is able to produce a better estimate of the surface chlorophyll concentration than the first guess deterministic simulation.Using SeaWIFS ocean color data observations, the statistical consistency (reliability) of this prior ensemble is demonstrated using rank histograms.Finally, the relevance of our approach in the prospect of ocean color data assimilation is demonstrated by considering a 3D optimal analysis of the ensemble (one updateat one time step) performed from the statistic errors of the stochastic ensemble simulation previously stated.During this experiment, the high resolution SeaWIFS ocean color data are assimilated using a Ensemble Transform Kalman Filter (ETKF) analysis scheme and the non gaussian behaviour and non linear relationshipbetween variables are taken into account using anamorphic transformations.More specifically, we show that the analysis of SeaWIFS data improves the representation and the ensemble statistics of chlorophyll concentrations.

M. Tech. (Department of Visual Arts and Design, Faculty of Human Sciences),Vaal University of Technology. / The sangoma cloth is one of the objects which the Zulu people use to utilised in terms of culture and tradition and still is significant amongst African diviners. Initially, sangomas (traditional healers/diviners) dressed in animal skin, but because of the lack or deficiency of the animal skin, the cloth substituted the skin. The cloth carries a wealth of sacred symbolism and meanings which have been constructed by the sangoma community to best fit or describe the symbolic meanings and the potencies embedded in them. However, such cultural artefacts and symbols change over time, and new ones emerge through cultural practice. Therefore, the tension between conserving the religious and sacred, on the one hand, and the emerging, context and contingency based development on the other leads to problems of acceptability, authorized use and sanctified adaptation. This project explores the symbolism in the meaning and function of the sangoma sacred cloth which forms part of the sangoma dress code. It sets out three sets of interwoven binaries or tensions. Firstly, it explores the tensions between the liminal of ritual practices, and the liminoid (following Turner 1969), so that the second set of tensions, namely between the sacred and the profane (or secular or the commodified) can be explored. This leads to the third set of tensions, namely between Indigenous Knowledge Systems on the one hand and a potential Global Knowledge System on the other. In this way the tensions in the use of the sangoma cloth was explored, to attempt to determine a system that would assist in defining at what moment and following what dynamics the symbology would move from one side of the set of tensions to the other. The artist/researcher worked together with a focus group of sangomas who are part of a nongovernmental organization are based in Sedibeng region. This study’s research methodology is a Practice-led research approach within the framework of qualitative research methodology in the Fine Arts. The first method of data collection included one-on-one interviews from which the data was analysed and from which the existing designs could be reworked into new ones. Following this, a series of design and artmaking processes were followed, where five original cloth designs were taken through six different redesign iterations. The third method was a focus group method where the focus group participants (consisting of the original sangoma community, but with a ritual to request insight from the ancestors/amadlozi and therefore their contributions) was employed to view the five sets of redesigned cloths, to attempt to establish the moment when the Indigenous Knowledge System and the sacred of the sangoma cloth enters the secular domain which forms part of Global Knowledge Systems. The research project offers one system or methodology which is based on comparison as presented by the community who claim originality, in that the community itself decide when something needs to be protected by IKS and when it may be allowed to move into a public, shared, domain. The findings of this project were done by the owners of the cloth which resulted in them stating that: to claim IKS, one has to make an inquiry with the community who owns it; one cannot claim an entire design as IKS due to the composition or design having individual elements which have distinct meanings; The element of colour plays a dominant role within the sangoma community; and finally, for this project a clear and powerful system of humanity was set out by the sangomas/amadlozi that the sacredness of the cloth lies with the human who wears or uses it, and not with the cloth itself.

Botswana, formerly known as the Bechuanaland Protectorate, is a country with diverse tribal and religious cultures. Bakalanga are one of the tribes found in Botswana and also in Westrn Zimbabwe. The Western part of the Zimbabwean Bukalanga region was included in the then Bechuanaland Protectorate when its border with Zimbabwe was fixed. To date, Botswana's traditional music has been passed from generation to generation, entirely orally. The main contribution of this study is collecting, documenting and preserving Bakalanga traditional music-making. After abolishing official usage of the Ikalanga language, at independence in 1966, in the early 1990's the Botswana government re-discovered that a nation without culture is a lost nation. Funds were then set aside to be used annually for the development of culture. In using these funds to revive their culture and traditional music, Bakalanga of North Eastern Botswana declared 21 May to be their annual cultural day. Photographs and video footage of these annual cultural festivals were taken by the researcher to help illustrate certain aspects of Ikalanga music and dance in this thesis. Several factors influencing Ikalanga traditional music were taken into consideration: the historical background of Bakalanga, their relationship with other tribes such as the Amandebele, their education, their language in relation to other languages and the missionary influence. Ikalanga traditional music instruments are described. The Mwali religion, which forms the basis of wosana music, linking Bakalanga of Botswana and those of Zimbabwe through the Njelele sacred place joint annual ceremonies, is discussed at length. Different Ikalanga traditional music types are addressed as follows: • Rain Making/Praying music; Wosana and Mayile • Traditional Music for Happy Occasions and Entertainment; Ndazula, Mukomoto, Woso, Iperu, Tshikitsha, Bhoro and Ncuzu./ Maskhukhu • Traditional Music for Healing Purposes; Mazenge (Shumba), Sangoma and Mantshomane. All the above music types are practised within Bukalanga communities publicly, with the exception of mazenge, which is regarded as sacred and private. Bhoro is also extinct in Zimbabwe. The notation of Ikalanga traditional basic musical themes is provided, except for mazenge and ncuzu. which were not found anywhere during this research. / Thesis (DMus)--University of Pretoria, 2006. / Music / unrestricted

This study explores trainees' experiences of power dynamics within a ritualised training context, with reference to the three major aspects of the study: training, ritual and power. The psychotherapeutic training took place at Agape, a community-based counselling service in Mamelodi, whose theoretical approach to training included a mixture of postmodern, ecosystemic and African traditions. A substantial literature survey examines the major concepts and issues related to the research subject, such as psychotherapeutic training approaches, the philosophies and theories that may inform training procedures, ritual practices in psychotherapy, and organisational and power aspects of psychotherapeutic training. The research process was executed using the qualitative, interpretive research methodology. A sample of six of the trainees who had completed their training at this placement was interviewed, and two of the trainers. The researcher's reflections on her own training experiences are woven into the material. Using the interview technique and through asking a series of open-ended questions, the researcher obtained an account of the subjective, sacralised training interactions at Agape. Themes were identified that had emerged during the interview process. In brief, the themes referred to trainees' theoretical and practical experiences in the training placement, how they made sense of the sacralised therapeutic experiences, and comments on their relationship with trainers and fellow trainees. The most common theme that emerged was that of power. The end product of this study portrays the trainees' understandings of power within a sacralised psychotherapeutic context and their responses to this. This study makes explicit the links between ritualisation and power within an evaluative psychotherapeutic training context, and the consequences of this for training. / Psychology / M.A. (Clinical Psychology)

This study explores trainees' experiences of power dynamics within a ritualised training context, with reference to the three major aspects of the study: training, ritual and power. The psychotherapeutic training took place at Agape, a community-based counselling service in Mamelodi, whose theoretical approach to training included a mixture of postmodern, ecosystemic and African traditions. A substantial literature survey examines the major concepts and issues related to the research subject, such as psychotherapeutic training approaches, the philosophies and theories that may inform training procedures, ritual practices in psychotherapy, and organisational and power aspects of psychotherapeutic training. The research process was executed using the qualitative, interpretive research methodology. A sample of six of the trainees who had completed their training at this placement was interviewed, and two of the trainers. The researcher's reflections on her own training experiences are woven into the material. Using the interview technique and through asking a series of open-ended questions, the researcher obtained an account of the subjective, sacralised training interactions at Agape. Themes were identified that had emerged during the interview process. In brief, the themes referred to trainees' theoretical and practical experiences in the training placement, how they made sense of the sacralised therapeutic experiences, and comments on their relationship with trainers and fellow trainees. The most common theme that emerged was that of power. The end product of this study portrays the trainees' understandings of power within a sacralised psychotherapeutic context and their responses to this. This study makes explicit the links between ritualisation and power within an evaluative psychotherapeutic training context, and the consequences of this for training. / Psychology / M.A. (Clinical Psychology)