A dissertation submitted to the Faculty of Engineering. University of the Witwatersrand. Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering. D.tT~.awart •• w1t~4i.tinotion on , Dec ••ber I,e7 Johannesburg. ItN7 / Accurate forecastinu of system Maximum Demand (MDl is vital ~o Esk011l. Under-estimating the MD could re-ul: in a generation capacity shortage. with devastating consequences for the economy. Similarly. a high MD forecast would result in overcapacity. with expensive generating plant standing idle The traditional method of MD forecasting in Eskorn has become unreliable due to a changing relationship between forecast energy sales and expected maximum demand. The reasons for the changing system demand profile were isolated and analysed. Alternative MD forecasting techniques are evaluated and end-use hourly aggregation modets were ;d'~ntifieJ as a method suitable for Eskorn, An experimental demand profile forecasting moue! was developed, using data from a previous project. The model was tested and proved able to cope with the structural changes in the system demand profile. This resulted in the adoption of this technique by Eskorn and approval for the devclopn-ent of a f\.JJ1 scale de manu profile forecasting model.

Le droit de mettre fin à une relation contractuelle comprend deux aspects : le droit de résilier un contrat à durée indéterminée et le droit de refuser de renouveler un contrat à durée déterminée. Son existence est incontestable à l’égard de l’ensemble des contrats de distribution, y compris ceux qui revêtent la qualification de mandat. Néanmoins, son exercice est encadré par la théorie de l’abus lorsque le titulaire de ce droit subjectif manque à un devoir moral du maintien temporaire de la relation contractuelle. Dans cette hypothèse, laresponsabilité civile du titulaire du droit est engagée sur le fondement de la notion de faute.Toutefois, ce même titulaire peut être contraint de payer une indemnité même en absence de toute faute commise de sa part : telle est l’hypothèse de l’indemnité de fin de contrat prévue au bénéfice d’une partie des distributeurs. Cependant, il ne faut pas interpréter cette indemnité comme une remise en cause de ce droit subjectif. En effet, cette indemnité trouve sa justification dans les éléments étrangers à ce droit. En d’autres termes, le paradoxe entre l’indemnité et le droit subjectif n’est qu’apparent : le droit de mettre fin à une relation contractuelle de distribution est dépassée par l’indemnité de fin de contrat. / The existence of the right to terminate a contractual relationship of distribution isundeniable, even though the exercise of this right is limited by the theory of abuse, a case of fault-based liability. However, sometimes the supplier should pay an indemnity even though they terminate a distribution agreement without fault.

by Tam, Pui Fun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 147-166). / Abstract also in Chinese. / List of Tables --- p.i / List of Figures --- p.ii / List of Plates --- p.v / Acknowledgements --- p.vi / Abstract (in English) --- p.vii / Abstract (in Chinese) --- p.ix / Chapter Chapter 1. --- General introduction --- p.1 / Chapter Chapter 2. --- Temporal and spatial distribution of Copepoda in the Zhujiang River estuary --- p.3 / Chapter 2.1 --- Literature review --- p.3 / Chapter 2.1.1 --- Physical properties of estuaries --- p.3 / Chapter 2.1.2 --- Factors affecting the zooplankton community --- p.4 / Chapter 2.1.2.1 --- Temperature --- p.4 / Chapter 2.1.2.2 --- River discharge and salinity --- p.5 / Chapter 2.1.2.3 --- Coastal hydrography --- p.6 / Chapter 2.1.2.4 --- Biological factors --- p.6 / Chapter 2.1.3 --- Site description of the Zhujiang River estuary --- p.7 / Chapter 2.2 --- Introduction --- p.9 / Chapter 2.3 --- Materials and methods --- p.10 / Chapter 2.4 --- Results --- p.13 / Chapter 2.4.1 --- Physical parameters and chlorophyll concentration --- p.13 / Chapter 2.4.2 --- Seasonal and spatial variations in the abundance of planktonic copepods --- p.17 / Chapter 2.4.3 --- Seasonal variations in the relative abundance of dominant copepods --- p.27 / Chapter 2.4.4 --- Relationship between copepod abundance and chlorophyll a concentration --- p.26 / Chapter 2.4.5 --- Seasonal and spatial distribution and salinity and temperature preference of dominant copepods --- p.30 / Chapter 2.5 --- Discussion --- p.41 / Chapter 2.5.1 --- Seasonal variations in copepod abundance --- p.41 / Chapter 2.5.2 --- Seasonal and spatial variations in species diversity --- p.43 / Chapter 2.5.3 --- Seasonal and spatial distribution of dominant species --- p.45 / Chapter 2.5.4 --- Seasonal succession and spatial segregation of dominant copepods --- p.51 / Chapter 2.5.5 --- Seasonal and spatial distribution of non-dominant copepods --- p.52 / Chapter 2.6 --- Conclusion --- p.60 / Chapter Chapter 3. --- "Spatial and temporal distribution of marine cladocerans in Tolo Harbour, Hong Kong" --- p.61 / Chapter 3.1 --- Literature review --- p.61 / Chapter 3.1.1 --- Geographical and seasonal distribution of marine cladocerans --- p.61 / Chapter 3.1.2 --- Vertical distribution --- p.65 / Chapter 3.1.2.1 --- Diel vertical migration --- p.65 / Chapter 3.1.2.2 --- Marine cladocerans as epiplankters --- p.68 / Chapter 3.1.2.3 --- Diel vertical distribution of marine cladocerans --- p.69 / Chapter 3.1.3 --- Horizontal distribution --- p.70 / Chapter 3.1.4 --- Reproduction --- p.71 / Chapter 3.1.5 --- Feeding --- p.72 / Chapter 3.1.5.1 --- Food composition --- p.72 / Chapter 3.1.5.2 --- Diel feeding behaviour --- p.74 / Chapter 3.16 --- Site description of Tolo Harbour --- p.77 / Chapter 3.2 --- Introduction --- p.79 / Chapter 3.3 --- Materials and methods --- p.80 / Chapter 3.3.1 --- Field sampling --- p.80 / Chapter 3.3.1.1 --- Physical parameters --- p.80 / Chapter 3.3.1.2 --- Ambient chlorophyll concentration --- p.82 / Chapter 3.3.1.3 --- Zooplankton sampling --- p.82 / Chapter 3.3.1.4 --- Gut pigment content --- p.83 / Chapter 3.3.2 --- Measurement of gut evacuation rate --- p.84 / Chapter 3.3.2.1 --- Gut evacuation rate --- p.85 / Chapter 3.3.2.2 --- Clearance rate --- p.86 / Chapter 3.3.3 --- Zooplankton distribution --- p.86 / Chapter 3.3.3.1 --- Quantitative analysis --- p.86 / Chapter 3.3.4 --- Statistical analysis --- p.92 / Chapter 3.3.4.1 --- Overall population --- p.92 / Chapter 3.3.4.2 --- Size --- p.93 / Chapter 3.3.4.3 --- Reproductive condition --- p.94 / Chapter 3.3.4.4 --- Gut pigment content and gut clearance rate --- p.95 / Chapter 3.4 --- Results --- p.96 / Chapter 3.4.1 --- Physical parameters and chlorophyll concentration --- p.96 / Chapter 3.4.2 --- Spatial and temporal distribution of marine cladocerans --- p.102 / Chapter 3.4.2.1 --- Species composition and abundance --- p.102 / Chapter 3.4.2.2 --- Vertical and horizontal distribution in general population --- p.105 / Chapter 3.4.2.3 --- Vertical and horizontal patterns in size distribution --- p.110 / Chapter 3.4.2.4 --- Distribution of marine cladocerans at different stages --- p.118 / Chapter 3.4.3 --- Feeding ecology of marine cladocerans --- p.125 / Chapter 3.4.3.1 --- Did variation in gut pigment content --- p.125 / Chapter 3.4.3.2 --- Gut evacuation rate --- p.125 / Chapter 3.4.3.3 --- Diel changes in clearance rate of Penilia avirostris --- p.129 / Chapter 3.5 --- Discussion --- p.132 / Chapter 3.5.1 --- "Diel vertical and horizontal distribution of 3 marine podonids: Pseudevadne tergestina, Podon sp. and Pleopis schmackeri" --- p.135 / Chapter 3.5.2 --- Diel vertical and horizontal distribution of Penilia avirostris --- p.138 / Chapter 3.5.3 --- Size distribution of marine cladocerans --- p.140 / Chapter 3.5.4 --- Feeding behaviour of marine cladocerans --- p.142 / Chapter 3.6 --- Conclusion --- p.145 / References --- p.147

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Esta dissertação tem como objetivo o estudo da distribuição ``slash\'\', considerando seus casos simétrico e assimétrico univariados. Serão apresentadas propriedades probabilísticas e inferenciais dessa distribuição, assim como peculiaridades e problemas. Para serem feitas inferências será considerado o enfoque clássico através do uso dos métodos dos momentos e máxima verossimilhança. São apresentados também os cálculos para a obtenção destes estimadores. Nos casos onde estes estimadores não podem ser obtidos algebricamente foram utilizados métodos computacionais, através da implementação do algoritmo EM. Para isto, foi utilizado o software R e os comandos estão no apêndice. No caso dos estimadores de máxima verossimilhança será implementado o método de Louis para estimar os elementos da matriz de informação de Fisher. Foram realizados estudos de simulação e aplicações para dados reais. Nas aplicações foi analisado o modelo de regressão linear simples, onde foi considerado que os erros seguem distribuição slash assimétrica. / This dissertation aims at studying the ``slash\'\' distribution considering its symmetric and asymmetric versions. We present probabilistic as well as inferential aspects of this distribution, including peculiarities and problems related to model fitting. The classical approach based on maximum likelihood estimation is used. Moments estimation is also considered as starting values for the maximum likelihood estimation. The implementation of the EM algorithm is developed for the implementation of the likelihood approach. For this implementation software R was used and codes required are presented in the Appendix. As a byproduct of the EM algorithm, Louis method is considered for estimating the Fisher information matrix which can be used for computing large sample intervals for model parameters. Extensions for a simple regression model is considered. Simulation studies are presented illustrating the performance of the estimation approach considered. Results of real data analysis indicate that the methodology can perform well in applied scenarios.

The biogeographical pattern of the brown macroalgal genus Sargassum as well as the phylogeography of selected Sargassum spp. along NW Pacific coast were elucidated using analytical biogeographical and comparative phylogeographical tools. / To investigate the effect of freshwater outflow from Yangtze and Yellow Rivers in eastern China in shaping the genetic population structure of Sargassum spp., a comparative phylogeographic study was conducted on four closely related Sargassum species showing either continuous (Sargassum thunbergii and S. muticum ) or discontinuous (S. hemihyllum and S. fusiforme) distribution patterns along the Chinese coast. The results showed discontinuously distributed species to exhibit more haplotypes (e.g. four in TrnW_I spacer) among their populations than those with continuous distribution (two in TrnW_I spacer) pattern. Little or no population differentiation is revealed in species with a continuous distribution. Their occurrences in the brackish Bohai region may be attributed to the presence of inherited physiochemical traits that allow them to tolerate lower salinity waters in estuaries. The discontinuously distributed species, however, exhibited a deep genetic divergence among populations, as revealed by various genetic markers. There are two main lineages of S. fusiforme based on ITS2 and TrnW_I sequences, but the geographical region associated with this genetic break between the two lineages in eastern and southwestern Japan is different from that of S. hemiphyllum. Analysis of molecular variance (AMOVA) results indicate that the maintenance of the population structure of S. fusiforme appears not to be correlated with the outflow of the two rivers. For S. hemphyllum, reduced salinity as the suspected genetic barrier was investigated directly in the laboratory to elucidate its effect on the growth and survival of S. hemiphyllum var. chinense . Statistically significant difference was observed in the relative growth rate (calculated based on wet weight) of branches cultured under different salinities, with the optimal growth under salinity level of 33 ppt. The lethal limit of vegetative growth was between 0 and 10 ppt. Germlings cultured in 15 ppt attained the highest survivorship. The optimal growth of the germlings occurred at 25 ppt, while the lowest lethal limit was within the range of 0 ppt and 5 ppt. Germlings reared under low salinity were deficient in rhizoid development, making them highly unlikely to grow into large thallus in the natural environment with strong waves. Compared with the optimal and lethal salinity level of S. mutium, the lethal limits of both vegetative branches and germlings of the two species are comparable. The optimal growth of branches of S. muticum occurred under salinity level of 27 ppt, in contrast to the optimal salinity level of S. hemiphyllum at 33 ppt. This could have explained the absence of S. hemiphyllum in brackish water and support the suggestion that river discharge serves as a barrier for the exchange of genetic materials among its populations. (Abstract shortened by UMI.). / Two allopatrically distributed varieties of S. hemiphyllum, v. chinense and v. hemiphyllum, are genetically distinct in terms of their internal transcribed spacer 2 (ITS2) and Rubisco spacer. The genetic break between these two varieties, with v. chinense distributed in southern Chinese coast and v. hemiphyllum in Japan and Korea, is situated in a region that includes Bohai, Yellow Sea and East China Sea, all of which were heavily influenced by the Yangtze and Yellow Rivers in China. An introgression of the mitochondrial (Mt) genome from v. chinense to v. hemiphyllum, possibly mediated by the Kuroshio Current, is evident based on the Mt marker TrnW_I spacer. Hybridization between the two varieties may still be ongoing since the concerted evolution of ITS2 is not yet saturated in the Korean population located geographically in-between the distribution of the two varieties. In contrast, no variation in ITS2 and Rubisco spacer is revealed in S. muticum, including the native Asian populations and introduced populations in Europe and North America. There is a fixed one-nucleotide difference in the TrnW_I spacer, between the population in eastern Japan and all the other populations examined. This finding supports the earlier suggestion that the source of the introduced S. muticum populations is western and central Japan (Seto Inland Sea), where the germlings of S. muticum have been associated with the Pacific oysters previously introduced for farming in Canada, UK and France in earlier years. / Cheang, Chi Chiu. / Advisers: Put O. Ang; Ka-Hou Chu. / Source: Dissertation Abstracts International, Volume: 73-09(E), Section: B. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 221-247). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Esta dissertação tem como objetivo o estudo da distribuição ``slash\'\', considerando seus casos simétrico e assimétrico univariados. Serão apresentadas propriedades probabilísticas e inferenciais dessa distribuição, assim como peculiaridades e problemas. Para serem feitas inferências será considerado o enfoque clássico através do uso dos métodos dos momentos e máxima verossimilhança. São apresentados também os cálculos para a obtenção destes estimadores. Nos casos onde estes estimadores não podem ser obtidos algebricamente foram utilizados métodos computacionais, através da implementação do algoritmo EM. Para isto, foi utilizado o software R e os comandos estão no apêndice. No caso dos estimadores de máxima verossimilhança será implementado o método de Louis para estimar os elementos da matriz de informação de Fisher. Foram realizados estudos de simulação e aplicações para dados reais. Nas aplicações foi analisado o modelo de regressão linear simples, onde foi considerado que os erros seguem distribuição slash assimétrica. / This dissertation aims at studying the ``slash\'\' distribution considering its symmetric and asymmetric versions. We present probabilistic as well as inferential aspects of this distribution, including peculiarities and problems related to model fitting. The classical approach based on maximum likelihood estimation is used. Moments estimation is also considered as starting values for the maximum likelihood estimation. The implementation of the EM algorithm is developed for the implementation of the likelihood approach. For this implementation software R was used and codes required are presented in the Appendix. As a byproduct of the EM algorithm, Louis method is considered for estimating the Fisher information matrix which can be used for computing large sample intervals for model parameters. Extensions for a simple regression model is considered. Simulation studies are presented illustrating the performance of the estimation approach considered. Results of real data analysis indicate that the methodology can perform well in applied scenarios.

De part leur importance médicale, leur capacité à évoluer et leur facilité de manipulations, les bêta-lactamases TEM-1 et plus récemment CTX-M-15, se sont imposées comme des modèles de biochimie mais aussi des modèles pour une étude évolutive des protéines. La caractérisation de la distribution de l'effet des mutations dans une protéine permet d'avancer dans la compréhension des mécanismes moléculaires et des contraintes influant sur l'évolution des gènes de résistance aux antibiotiques et de façon plus globale sur les protéines.Par une approche de mutagénèse exhaustive suivie d’une évolution expérimentale sous sélection antibiotique couplée à du séquençage à haut débit, nous avons pu déterminer et décrire la distribution des effets des mutations dans la protéine TEM-1. Trois catégories de mutants ont été identifiées comme ayant des comportements différents en termes de cinétique de mort face à l'antibiotique. Des études phénotypiques ont permis de proposer un scénario impliquant une saturation progressive des principales protéines liant la pénicilline en fonction de l’activité hydrolytique du mutant de bêta-lactamase. Enfin, un modèle biochimique qualitatif compatible avec cette cinétique est proposé. La comparaison des effets des mutations entre TEM-1 et CTX-M-15, deux bêta-lactamases de la famille des sérines protéases de classe A et homologue à 30%, permet d’étudier la notion de contexte-dépendance des mutations. Notamment, à travers le résidu 251 qui est différent entre ces 2 protéines et intolérant aux mutations, nous replaçons cette problématique dans une perspective évolutive globale. Cela nous permet d’étudier les incompatibilités mutationnelles au sein des protéines et les possibilités de compensation des sites destabilisés. Nous observons une compensation à la fois globale, au travers de l’effet sur la stabilité, mais aussi locale avec une épistasie forte entre le résidu 251 et le site compensateur. Enfin, afin d’étudier de façon exhaustive les intéractions épistatiques dans les protéines, nous nous sommes focalisés sur une hélice alpha de la protéine TEM-1. L’étude de près de 73% des 22000 combinaisons mutationnelles possibles a permis de souligner l’importance de la stabilité thermodynamique, celle-ci expliquant une grande part des effets des mutations. Cependant, un contingent d’interactions ne semble pas expliquable par ce modèle ce qui montre l’importance des interactions locales au sein des hélices. Le couplage de ces approches évolutives quantitatives et mécanistiques permettent à la fois d’avancer dans la compréhension des contraintes qui sous-tendent l’évolution des protéines mais aussi de plonger au cœur de la résistance aux antibiotiques et de ses mécanismes moléculaires. / Beta-lactamases TEM-1 and more recently CTX-M-15 are antibiotic resistance enzymes that combine a medical importance, a fast evolution in the wild and are easy amenable to manipulation in the laboratory. As such, they have become models of biochemistry and also models for the study of protein evolution. The characterization of the distribution of mutational effect within a protein shed light on the molecular mechanisms and the constraints influencing the evolution of proteins.Using an exhaustive mutagenesis approach followed by an experimental evolution under antibiotic selection coupled with high-throughput sequencing, we were able to determine and describe the distribution of the effects of mutations in the TEM-1 protein. Three categories of mutants have been identified as having different behaviors in terms of survival kinetics when facing the antibiotic. Phenotypic studies have allowed us to propose a scenario involving a progressive saturation of the main penicillin-binding proteins as a function of the hydrolytic activity of the beta-lactamase mutant. Finally, a qualitative biochemical model compatible with this kinetic is proposed.I then compared the fitness effects of mutations in TEM-1 and CTX-M-15, which are two beta-lactamases of the class A serine protease family with 30% homology. I focused on the context dependency of mutation effects and concentrated my analysis on residue 251, which harbor a different aminoacid in each of the enzyme that is not functional when inserted in the other protein. I further studied how mutations in the rest of the protein could compensate that incompatibility. Compenstation was found to be associated to mutations acting presumably through on overall effect on protein stability, and on some cases to some local interactions with residue 251.Finally, in order to study exhaustively the epistatic interactions in proteins, we focused one alpha helix of TEM-1. The study of nearly 73% of the 22,000 possible mutational combinations made it possible to underline the importance of thermodynamic stability, which explains a large part of the effects of mutations. However, a contingent of interactions does not seem to be explained by this model, which shows the importance of the local interactions within the helices.The coupling of these quantitative and mechanistic evolutive approaches makes it possible both to advance in understanding the constraints underlying the evolution of proteins but also to plunge into the heart of resistance to antibiotics and its molecular mechanisms.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 104-107). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 104-107). Also available on the Internet.