Thesis (Ph. D. in Environmental Science)--Vanderbilt University, Aug. 2007. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 232-236).

Th. 3e cycle--Phys. de la matière et du rayonnement--Grenoble 1, 1983. N°: 51.

Th. doct.-ing.--Génie civil--Toulouse--I.N.S.A., 1982. N°: 65.

High intensity proton synchrotrons provide beams for several types of facility around the world, including spallation neutron sources and high energy physics experiments. The defining feature of these particle accelerators, that of intense beams, is tightly coupled to what limits the intensity, which is the controlled loss of beam particles. Many different factors contribute to beam loss. Beam will be lost on injection to a synchrotron and may be lost on extraction or in transfer lines. Non-linearities in the accelerator lattice can introduce driving terms for resonant beam behaviour. Collective effects between the beam particles and with the beam environment modify the single particle behaviour considerably. High intensity loss that occurs in the transverse plane, due to space charge and image fields, was investigated. The rapid cycling synchrotron at the ISIS Spallation Neutron Source in the UK was the focus for all of the work. The ISIS Synchrotron has many particular features which were described. One such feature is the conformal rectangular vacuum vessel, which takes the shape of the design beam envelope with certain modifications. This vacuum vessel has a complex effect on beam image fields. Numerical tools to study the space charge and image fields at ISIS were created and reported. The tools included two Poisson solvers to study space charge and images which were benchmarked against commercially available algorithms. A two dimensional particle-in-cell tracking code was created using the space charge solvers in combination with either a smooth focusing lattice model or one which generated Twiss matrices. A variety of diagnostic tools were available. A survey of existing analyses for pencil beams in parallel plate and rectangular geometry was made. Results from the analysis were then compared with two dimensional simulations with round uniform beams in rectangular geometry. Differences and extensions to the analysis were summarised. Coefficients for higher order image terms were defined and tabulated. The two dimensional nature of the image field was discussed and values for the coefficients for certain higher order terms identified in the plane orthogonal to the beam offset. Solutions for closed orbits produced with single and harmonic kicks at low and high intensity were discussed and simulated. A model was proposed which included the higher order image coefficients produced by the closed orbits. A single particle model was then explored which obtained resonance conditions from the closed orbits and image coefficients. The effect of self-consistent coherent motion on the results was discussed. Particle-in-cell beam tracking simulations were used to explore the results of this analysis numerically. Image resonances were found and described for a variety of simulation parameters starting with a smooth focusing lattice and uniform density beam, then progressing to more realistic cases including waterbag beams, alternating gradient lattices and conformal vacuum vessels. Image resonances described by the models were reported as were others that needed further explanation. Their possible impact for ISIS was discussed. New experiments with coasting beams at ISIS were carried out to explore the relationship between tune and beam loss at low intensity. Such experiments are a vital first step to understanding high intensity behaviour. It was shown that ISIS has existing lattice nonlinearities (some known, some unknown) which will need to be taken into account for high intensity experiments and simulations. Finally this work was put into context by examing specific transverse space charge effects for a proposed ISIS upgrade and including ideas developed throughout the thesis. Estimates were made of the strength of space charge effects and emittance scaling using conventional methods. The particle tracking tools developed for the thesis were then used to study beam behaviour with lattice gradient errors, the effects of closed orbits and changes to the working point. The transverse calculations and simulations suggested that the upgrade was feasible.

[pt] Aplicação de duas metodologias baseadas em estatísticas adaptativas, com a finalidade de modelar e prever o comportamento de uma série temporal (série histórica de carga elétrica horária) gerada pela concessionária de energia elétrica Light. Foi aplicada à série de carga elétrica horária a metodologia de amortecimento direto, utilizada para a previsão horária e diária de carga e o modelo de previsão adaptativa de carga elétrica horária de curto prazo (GUPTA, P.C.), utilizado para a previsão diária de carga. É demonstrado o bom desempenho do método de amortecimento direto na previsão horária de carga elétrica. Na previsão diária, o modelo de previsão adaptativa de curto prazo de cargas elétricas horárias (GUPTA, P.C) apresenta resultados superiores aos do método de amortecimento direto. / [en] Application of two methodologies, based on adaptive statistics, in order to model and forecast the behavior of time serie (hourly loads) generated by electric utility Light. Was applied to the times series methodology of direct smoothing model (hourly and 24-hours load forecasting) and the methodology of adaptive short-term forecasting of hourly loads (GUPTA, P.C.) (24-hours load forecasting). It is shown the good performance of the direct smoothing model in the hourly forecasting. In the 24-hours load forecasting, the model of adaptive short-term forecasting of hourly loads (GUPTA, P.C.) shows better results than direct smoothing model.

C-type cytochromes are ubiquitous proteins with crucial functions in organisms, which include electron transfer and apoptotic signalling. In eukaryotic organisms, mitochondrial cytochrome c is located in the intermembrane space, and it is a component of the electron transport chain; it is responsible for transferring electrons from Complex III to Complex IV. The regulated release of cytochrome c from mitochondria results in the activation of a signal transduction pathway leading to controlled cell death, or apoptosis. In mitochondrial c-type cytochromes, the heme is bound to both cysteines of a CXXCH motif located near the N-terminus. The covalent heme attachment in c-type cytochromes, the final step in its biosynthesis, is achieved by different cytochrome c biogenesis systems in different organisms. Out of these systems, System III, found in many eukaryotes, has a single component - holocytochrome c synthase (HCCS) which is the enzyme responsible for the catalysis of heme binding to cytochrome c. HCCS recognises apocytochrome c as a substrate upon the import of the apocytochrome from the cytosolic space to the mitochondrial intermembrane space. The requirements of amino acid sequence for HCCS recognition had remained an intriguing question, despite the relatively long period since the discovery of the enzyme. Thus, HCCS in System III and its substrate recognition is the subject of this thesis. This thesis describes the experiments showing that the N-terminal region of the mitochondrial cytochrome c protein is important for substrate recognition, as well as further characterisation of this sequence by mutagenesis. Out of several highly conserved residues in the N-terminus, a phenylalanine residue in the N-terminus is identified to be critical for heme attachment by HCCS. The role of this phenylalanine residue in the interaction between the two proteins was probed by substituting it with a range of residues. Furthermore, the importance of the spacing between the key phenylalanine residue and the CXXCH motif was investigated. A single-cysteine variant of the mitochondrial cytochrome c with a single bond to the heme is produced by HCCS, but heme attachment only occurs if histidine is present as an axial ligand to the heme iron. Replacement of the histidine with other potential iron-ligating residues abolished heme attachment. These results bring insight into the critical features in amino acid sequence of cytochrome c for the substrate recognition specificity of HCCS. Sequence analysis on the N-terminal region of mitochondrial cytochromes c in a variety of organisms reveals evolutionary implications for cytochrome c biogenesis systems. It also attempts to explain the reason for negative results in previous chapters for the analysis of the N-terminal region of cytochrome c. An improved method for human HCCS production is also described in this thesis, for the exploitation of purification and characterisation in future studies of HCCS.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-02-01T12:41:42Z No. of bitstreams: 3 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Antonio Cleriston para Bibliotecas pdf Thiago.pdf: 14553311 bytes, checksum: 304ef50f8ae4e7c26fff6c03cb4fc37b (MD5) Tese Antonio Cleriston para Bibliotecas pdf Thiago.pdf: 14553311 bytes, checksum: 304ef50f8ae4e7c26fff6c03cb4fc37b (MD5) / Made available in DSpace on 2016-02-01T12:41:42Z (GMT). No. of bitstreams: 3 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese Antonio Cleriston para Bibliotecas pdf Thiago.pdf: 14553311 bytes, checksum: 304ef50f8ae4e7c26fff6c03cb4fc37b (MD5) Tese Antonio Cleriston para Bibliotecas pdf Thiago.pdf: 14553311 bytes, checksum: 304ef50f8ae4e7c26fff6c03cb4fc37b (MD5) Previous issue date: 2011 / O presente estudo analisa os processos de enunciação da charge através da articulação de seus elementos constitutivos em relação ao todo compositivo; e propõe um aparato teórico-metodológico de análise da produção de seus efeitos de sentido. Situa conceitualmente a charge no campo do Humor Gráfico, procedendo às devidas distinções com o desenho de humor, o cartum, a caricatura, os quadrinhos e a ilustração de humor. Para obtenção de êxito uma centena de charges foi examinada a fim de se verificar as estratégias enunciativas em sua discursividade gráfica e verbal. Para se compreender o fenômeno da interação dialógica entre interlocutores situados no tempo e no espaço, o trabalho se fundamenta na perspectiva da linguagem posta por M. Bakhtin, coadjuvada pelos princípios da Análise do Discurso postos por Dominique Maingueneau, dentre outras contribuições. / This study analyzes the processes of enunciation of the editorial cartoon through the articulation of its constitutives elements in relation to all the compositional; and proposes a methodological-theoretical apparatus of analysis of the production of its meaning effects. Is conceptually the editorial cartoon in the field of graphic humor, making the necessary distinctions with the caricature, cartoon – gag humor, comic strip and editorial illustration. To obtain success a hundred charges was examined in order to verify the enunciatives strategies in their graphic and verbal discursivity. To understand the phenomenon of dialogic interaction between interlocutors situated in time and space, the work is based on the perspective of language made by M. Bakhtin, assisted by the principles of discourse analysis by the Dominique Maingueneau’s point of view, among other contributions.

Com hipóteses de simetria plana e que a distribuição inicial de cargas, ocupa totalmente a amostra (tocando os dois eletródios), estudou-se o problema do movimento de carga espacial livre (M.C.E.L.) monopolar, em sólidos isolantes, submetidos à uma d.d.p. conhecida. Utilizando o método das características, reduziu-se o problema à um sistema de duas equações diferenciais ordinárias,de ia. ordem. O método foi aplicado para as distribuições linear, exponencial e p ~ x -1/2 , sob condições de curto circuito. são apresentados gráficos relativos à evolução temporal do perfil da densidade de cargas e da corrente externa. Estes resultados são comparados com outros obtidos por um cálculo aproximado, baseado em princípios variacionais . / Assuming planar symmetry and an arbitrary charge distribution that spreads through the sample, the one-carrier free - space-charge motion is studied in insulators solids. Using the method of characteristics we can reduce the problem t o the resolution of a system of two ordinary first order differential equations. Results are applied for linear, exponential and S.C.L. current charge distributions , under short-circuit conditions, The charge distribution for several times and the discharge currents are presented. The results are compared with those coming from an approximated method, based on variational principles.

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