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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Regressão binária bayesiana com o uso de variáveis auxiliares / Bayesian binary regression models using auxiliary variables

Rafael Braz Azevedo Farias 27 April 2007 (has links)
A inferência Bayesiana está cada vez mais dependente de algoritmos de simulação estocástica, e sua eficiência está diretamente relacionada à eficiência do algoritmo considerado. Uma prática bastante utilizada é a introdução de variáveis auxiliares para obtenção de formas conhecidas para as distribuições {\\it a posteriori} condicionais completas, as quais facilitam a implementação do amostrador de Gibbs. No entanto, a introdução dessas variáveis pode produzir algoritmos onde os valores simulados são fortemente correlacionados, fato esse que prejudica a convergência. O agrupamento das quantidades desconhecidas em blocos, de tal maneira que seja viável a simulação conjunta destas quantidades, é uma alternativa para redução da autocorrelação, e portanto, ajuda a melhorar a eficiência do procedimento de simulação. Neste trabalho, apresentamos propostas de simulação em blocos no contexto de modelos de regressão binária com o uso de variáveis auxiliares. Três classes de funções de ligação são consideradas: probito, logito e probito-assimétrico. Para as duas primeiras apresentamos e implementamos as propostas de atualização conjunta feitas por Holmes e Held (2006). Para a ligação probito-assimétrico propomos quatro diferentes maneiras de construir os blocos, e comparamos estes algoritmos através de duas medidas de eficiência (distância média Euclidiana entre atualizações e tamanho efetivo da amostra). Concluímos que os algoritmos propostos são mais eficientes que o convencional (sem blocos), sendo que um deles proporcionou ganho superior a 160\\% no tamanho efetivo da amostra. Além disso, discutimos uma etapa bastante importante da modelagem, denominada análise de resíduos. Nesta parte adaptamos e implementamos os resíduos propostos para a ligação probito para os modelos logístico e probito-assimétrico. Finalmente, utilizamos os resíduos propostos para verificar a presença de observações discrepantes em um conjunto de dados simulados. / The Bayesian inference is getting more and more dependent of stochastic simulation algorithms, and its efficiency is directly related with the efficiency of the considered algorithm. The introduction of auxiliary variables is a technique widely used for attainment of the full conditional distributions, which facilitate the implementation of the Gibbs sampling. However, the introduction of these auxiliary variables can produce algorithms with simulated values highly correlated, this fact harms the convergence. The grouping of the unknow quantities in blocks, in such way that the joint simulation of this quantities is possible, is an alternative for reduction of the autocorrelation, and therefore, improves the efficiency of the simulation procedure. In this work, we present proposals of simulation using the Gibbs block sampler in the context of binary response regression models using auxiliary variables. Three class of links are considered: probit, logit and skew-probit. For the two first we present and implement the scheme of joint update proposed by Holmes and Held (2006). For the skew-probit, we consider four different ways to construct the blocks, and compare these algorithms through two measures of efficiency (the average Euclidean update distance between interactions and effective sample size). We conclude that the considered algorithms are more efficient than the conventional (without blocks), where one of these leading to around 160\\% improvement in the effective sample size. Moreover, we discuss one important stage of the modelling, called residual analysis. In this part we adapt and implement residuals considered in the probit model for the logistic and skew-probit models. For a simulated data set we detect the presence of outlier used the residuals proposed here for the different models.
102

Estudo das reações de alilação de aldeídos promovidas pelo NbCl5 na presença de (R)-BINOL e (S)-4-benziltiazolidino-2-tiona como auxiliares quirais / Study reactions of allylation of aldehydes promoted by NbCl5 in the presence of (R)-BINOL and (S)-benzylthiazolidine - 2 - thione as a chiral auxiliary

Pimentel, Fernanda de Sousa Fernandes 12 June 2015 (has links)
Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-02-12T14:11:12Z No. of bitstreams: 2 Dissertação - Fernanda de Sousa Fernandes Pimentel - 2015.pdf: 3552044 bytes, checksum: 6506fc310b497a929ec9acf4d4db5942 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-16T06:47:11Z (GMT) No. of bitstreams: 2 Dissertação - Fernanda de Sousa Fernandes Pimentel - 2015.pdf: 3552044 bytes, checksum: 6506fc310b497a929ec9acf4d4db5942 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-16T06:47:11Z (GMT). No. of bitstreams: 2 Dissertação - Fernanda de Sousa Fernandes Pimentel - 2015.pdf: 3552044 bytes, checksum: 6506fc310b497a929ec9acf4d4db5942 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-12 / The allylation reaction of allyl organometallic compounds with aldehydes promoted by Lewis acids in the presence of chiral auxiliaries are a kind of nucleophilic addition reaction to control the stereochemistry of the product. The (R) -BINOL and (S) -4-benzylthiazolidine-2-thione compounds are used as chiral auxiliaries in asymmetric synthesis, although the literature describing the application of the first allylation reaction in the presence of various Lewis acids, it was not employed in the presence of niobium pentachloride. For the second compound, its application is limited to the aldol reactions and their study on enantioselective allylation reactions of aldehydes in the presence of Lewis acids was not described in the main databases used in this research. Therefore, this study investigated the application of these two compounds as chiral inductors in addition reactions of allyl tri-n-butilestanana to aldehydes in the presence of Lewis acid such as NbCl5. To optimize the reaction conditions used the p-nitrobenzaldehyde and was found to influence the proportion of the reactants in enantioselectivity and reaction yields. It was observed that the best yields (between 63-65% using (R)-BINOL and 41-50% using (S)-4-benzylthiazolidine-2-thione) were obtained when ethyl ether is used as solvent one temperature of -15 °C. However, the best enantioselectivity using a chiral auxiliary (R)-BINOL was obtained when the reaction rose while stirring for 1 hour the reaction between (R)-BINOL and NbCl5, then adding the aldehyde and stirred for 30 minuitos using diethyl ether and methylene chloride at -15 °C and -75 °C temperature conditions. On the other hand, the best enantioselectivity using the chiral auxiliary (S)-4-benzylthiazolidine-2-thione was obtained when it was used NbCl5 Lewis acid followed by stirring the reaction for 10 minutes and addition of diethyl ether as solvent under the conditions -15 °C temperature. / As reações de alilação de aldeídos com compostos organometálicos alílicos promovidas por ácidos de Lewis na presença de auxiliares quirais são um tipo de reação de adição nucleofílica para o controle da estereoquímica do produto. O (R)-BINOL e a (S)-4-benziltiazolidino-2-tiona são compostos utilizados como auxiliares quirais em síntese assimétrica e embora a literatura descreva a aplicação do primeiro em reações de alilação na presença de vários ácidos de Lewis, o mesmo não foi empregado na presença do pentacloreto de nióbio. No caso do segundo composto, a sua aplicação se limita as reações aldólicas e o seu estudo em reações de alilação enantiosseletiva de aldeídos na presença de ácidos de Lewis não foi descrito nas principais bases de dados utilizados nesta pesquisa. Portanto, nesse trabalho investigou-se a aplicação desses dois compostos como indutores quirais em reações de adição de alil-tri-n-butilestanana a aldeídos na presença de NbCl5 como ácido de Lewis. Para otimizar as condições reacionais utilizou-se o p-nitrobenzaldeído e verificou-se a influência da proporção dos reagentes na enantiosseletividade e nos rendimentos da reação. Percebe-se que os melhores rendimentos (entre 63-65% utilizando o (R)-BINOL e 41-50% utilizando a (S)-4-benziltiazolidino-2-tiona) foram obtidos quando o éter etílico foi utilizado como solvente a uma temperatura de -15ºC. Porém, a melhor enantiosseletividade utilizando o auxiliar quiral (R)-BINOL foi obtida quando elevou-se o tempo reacional para 1 hora de agitação na reação entre (R)-BINOL e o NbCl5, seguida da adição do aldeído e agitação por 30 minuitos, utilizando éter etílico e cloreto de metileno nas condições de temperatura de -15ºC e -75ºC. Por outro lado, a melhor enantiosseletividade utilizando o auxiliar quiral (S)-4-benziltiazolidino-2-tiona foi obtida quando utilizou-se o ácido de Lewis NbCl5 seguido pela agitação da reação por 10 minutos e adição de éter etílico como solvente nas condições de temperatura de -15ºC.
103

Construções com o verbo acabar em português brasileiro / Constructions with the verb acabar in brazilian portuguese

Aline Garcia Rodero 30 June 2010 (has links)
Neste trabalho, propomos uma análise do verbo acabar e de algumas das sentenças em que ele pode aparecer à luz de modelos formais para a análise linguística. Buscamos investigar as características sintático-semânticas dessas sentenças e procuramos identificar que tipo de estrutura sintática melhor representa sua formação. Travaglia (2004b) discute a poligramaticalização do verbo acabar e mostra que esse verbo está se gramaticalizando em sentidos diferentes. Esse autor aponta sete valores gramaticais em diferentes estágios de gramaticalização para tal verbo, além do sentido como verbo pleno. Sugerimos uma redução das oito possibilidades de interpretação de acabar sugeridas por Travaglia a cinco, pois quatro dos exemplos diferenciados por aquele autor parecem permitir uma mesma leitura. Nas sentenças que analisamos nesta dissertação, fazemos um recorte abrangendo o verbo acabar que traz uma idéia de resultado ou fase final de um evento, com uma leitura algo aconteceu e, no final das contas, a situação terminou de tal forma. Vários testes foram feitos para definir o estatuto desse verbo, como auxiliar ou como aspectualizador, porém esses testes não apontam para uma mesma direção. Observamos que acabar não apresenta um comportando uniforme, ora comportando-se como um verbo auxiliar, ora como um aspectualizador. Apesar do grande número de características que observamos para esse verbo comportando-se como um auxiliar, o consideramos como um aspectualizador (na terminologia de Wachowicz (2005, 2007)), principalmente pelo fato de operar sobre o intervalo de tempo denotado pelo verbo principal, restringindo esse intervalo para sua fase final ou para seu resultado, que é uma forte característica dos aspectualizadores, conforme Lunguinho (2005, 2009) e Wachowicz (2005, 2007). Esse verbo apresenta todas as características de alçamento perante os testes propostos por Davies & Dubinsky (2004). O verbo acabar está selecionando uma proposição em todos os exemplos em foco neste trabalho, uma small clause, e o sujeito lógico da predicação no núcleo dessa small clause alça para a posição de sujeito superficial. O verbo acabar funciona como um verbo inacusativo, selecionando apenas um argumento interno, no caso, uma SC. Ferreira (2009) prevê que um verbo inacusativo funcione como uma construção de alçamento. Essa autora considera os auxiliares como um subgrupo dos verbos inacusativos e esses, por sua vez, como um subgrupo dos verbos de alçamento. Por conta disso, prevemos que acabar esteja em uma intersecção entre os subgrupos de verbos inacusativos que selecionam uma SC, um CP, um DP e os verbos auxiliares, já que apresenta algumas características desse último. Comparamos as propriedades de acabar com algumas propriedades das passivas das línguas naturais, como discutido em Jaeggli (1986). Duas das propriedades das passivas das línguas naturais são também propriedades dos verbos inacusativos e, logo, dos verbos de alçamento: i) o NP na posição de sujeito não recebe papel-; e ii) o NP na posição de VP não recebe Caso verbal. Então, essas propriedades se verificam tanto para as passivas quanto para o verbo acabar, porém de formas um pouco diferentes. Sendo assim, essas construções podem ter uma mesma leitura, mas não a mesma estrutura sintática. É possível estabelecer uma relação entre as sentenças passivas e as estruturas de alçamento em que acabar pode ocorrer, devido ao fato de verbos auxiliares e inacusativos apresentarem propriedades de verbo de alçamento, como explicado em Ferreira (2009). Além disso, passivas podem apresentar algumas características comuns àquelas construções. Assim, obtemos uma leitura parecida para todas essas construções. / In this dissertation, we offer an analysis of the verb acabar and some sentences in which it can figure according to the formal linguistics. We investigate the syntactic-semantic characteristics of these sentences and try to identify what kind of syntactic structure best represents them. Travaglia (2004b) discusses the poligrammaticalization of the verb acabar and shows that this verb is grammaticalizing in different ways. This author shows seven grammar values in different levels of grammaticalization for this verb, besides its meaning as a lexical verb. We suggest a reduction of these eight possibilities to interpret acabar into five, since four examples analysed in different ways by that author seems to allow a same reading. In the sentences we analyse in this dissertation, we reduce the scope of our investigation only to the verb acabar that brings an idea of an event result or final phase, bringing a reading like: something happened and, by the end, the situation ended up like this. Many tests were done to define this verb as an auxiliary or aspectualizer, but these tests dont show the same results. We observe that acabar dont exhibit an uniform behaviour, sometimes working as an auxiliary verb, other times as an apectualizer. In spite of the great range of characteristics that we observe for this verb behaving as an auxiliary, we consider it an aspectualizer (following Wachowicz (2005, 2007)), mainly due to the way it works over the time interval expressed by the main verb, restricting this interval to its final phase or to its result, that is a strong characteristic for the aspectualizers, according to Lunguinho (2005, 2009) and Wachowicz (2005, 2007). This verb shows all raising characteristics according to the tests proposed by Davies & Dubinsky (2004). The verb acabar is selecting a proposition in all of the examples in focus on this dissertation, a small clause, and the logical subject of the predicate in the nucleus of this small clause raises to a superficial subject position. The verb acabar works as an unnacusative verb, selecting only one internal argument, in this case, a SC. Ferreira (2009) assumes that an unnucusative verb behaves as a raising structure. This author considers auxiliaries as a subgroup of the unnacusatives, and the later verbs, as a subgroup of the raising verbs. For this reason, we assume that acabar is in crossroads between unnacusative verbs subgroup that selects a SC, a CP, a DP and the auxiliary verbs, since it shows some characteristics of these verbs. We compare the properties of acabar with some properties of passives in natural languages, as discussed in Jaeggli (1986). Two of the three properties of passives in natural languages are also the properties of unnacusative verbs and, consequently, of raising verbs: i) the NP in the subject position doesnt receive a -role; and ii) the NP in the position of VP doesnt receive structural Case. So, these properties are true not only for the passives, but also for the verb acabar, but in different ways. Then, these constructions can have the same reading, but not the same syntactic structure. It is possible to establish a relation between these passive sentences and the raising structures in which acabar can occur, in spite of the fact that auxiliary verbs and unnacusatives present properties of raising verbs, as discussed in Ferreira (2009). Besides, passives can present some characteristics common to that constructions. Then, we get a similar reading to all of these constructions.
104

Introdução de dados auxiliares na classificação de imagens digitais de sensoriamento remoto aplicando conceitos da teoria da evidência

Lersch, Rodrigo Pereira January 2008 (has links)
Nesta tese investiga-se uma nova abordagem visando implementar os conceitos propostos na Teoria da Evidencia para fins de classificação de imagens digitais em Sensoriamento Remoto. Propõe-se aqui a utilização de variáveis auxiliares, estruturadas na forma de Planos de Informação (P.I.s) como em um SIG para gerar dados de confiança e de plausibilidade. São então aplicados limiares aos dados de confiança e de plausibilidade, com a finalidade de detectar erros de inclusão e de omissão, respectivamente, na imagem temática. Propõe-se nesta tese que estes dois limiares sejam estimados em função das acurácias do usuário e do produtor. A metodologia proposta nesta tese foi testada em uma área teste, coberta pela classe Mata Nativa com Araucária. O experimento mostrou que a metodologia aqui proposta atinge seus objetivos. / In this thesis we investigate a new approach to implement concepts developed by the Theory of Evidence to Remote Sensing digital image classification. In the proposed approach auxiliary variables are structured as layers in a GIS-like format to produce layers of belief and plausibility. Thresholds are applied to the layers of belief and plausibility to detect errors of commission and omission, respectively on the thematic image. The thresholds are estimated as functions of the user’s and producer’s accuracy. Preliminary tests were performed over an area covered by natural forest with Araucaria, showing some promising results.
105

Beyond a deficit-based approach : public sector audit as a transformative mechanism for positive change

Sweeney, John P. January 2018 (has links)
Public service operates in an accountability environment, characterised by complex relationships among auditors, auditees, and stakeholders. Public sector audit provides important information to stakeholders, but it is not always so effective in transforming and improving management. This research explores audit's potential to become an instrument for positive change, by addressing a knowledge-gap about intrapersonal, interpersonal, and interorganisational characteristics that would inhibit or facilitate such a paradigm shift. It found that audit has the capacity and potential to move beyond a purely deficit-based role, to positively promote improvements and collaborative learning between institutions and stakeholders. The studies obtained data from semi-structured interviews, survey questionnaires, and documents from 13 Supreme Audit Institutions in the period 2015-2017. The first study presents a unique competency model for performance auditors, identifying citizenship, creativity, and the love of learning, as distinctive competencies, congruent with a positive audit approach. The second study explores the auditor's view of the auditor-auditee relationship using role theory and identifies distinct psychological assets used by auditors: independence, competence, positive personal attributes, collaboration, fairness, and positive change; the latter two forming scale constructs to measure adaptive relational attitudes. The third study evaluates the effectiveness of cognitive-based training in influencing auditors' attitudes to audit relationships. The final study identifies three critical factors influencing interorganisational learning in an accountability context: organisations' absorptive and teaching capacity; dynamic interorganisational processes, and the commitment, knowledge, and ability of staff. This thesis provides new insights into applying psychological theories on relationships in a public sector audit setting. It addresses practical issues affecting the recruitment and selection of staff and the design of better audit processes. It concludes that public sector audit already possesses the theoretical and practical attributes to become a proactive, collaborative, participatory activity. Thus, by expanding its role, it can be a dynamic, transformative instrument for positive change.
106

The auxiliary verbs and the deficient verbs in Tswana

Setshedi, Jacob Ediasefagwa January 1974 (has links)
Thesis (M. A. (African Languages)) -- University of the North, 1974 / Refer to the document
107

Biochemical techniques for the study of voltage-gated sodium channel auxiliary subunits

Molinarolo, Steven 01 May 2018 (has links)
Voltage-gated sodium channels auxiliary subunits evolutionary emerged nearly 500 million years ago during the Cambrian explosion. These subunits alter one the most important ion channels to electrical signaling, the voltage-gated sodium channels support the propagation of electric impulses in animals. The mechanism for the auxiliary subunits effects on the channels is poorly understand, as is the stoichiometry between the auxiliary subunit and the channel. The focus of my thesis is to generate assays and to use these approaches to understand the interactions different types of voltage-gated channels and their auxiliary subunits. A biochemical approach was taken to identify novel interactions between the eukaryotic sodium channel auxiliary subunits and a prokaryotic voltage-gated sodium channel, a protein that diverged from the eukaryotic voltage-gated sodium channels billions of years ago. These interactions between the auxiliary subunits and channels were probed with chemical and photochemical crosslinkers in search of interaction surfaces and similarity to explain the mechanisms of interaction. The work in this thesis identified novel interactions between the voltage-gated sodium channel auxiliary subunits and voltage-gated channels that are distantly related to the voltage-gated sodium channels principally thought to be modulated by the auxiliary subunits. From this work a rudimentary concept can be theorized that the voltage-gated sodium channel β-subunits and not only β1 have a more primary role in electrophysiology by associating with multiple different types of ion channels.
108

An overview of dental assistant utilisation (DAU) and recommendations for the establishment of an undergraduate DAU programme in Australia

McLaughlan, Anthony Charles January 1993 (has links)
Master of Dental Surgery / At the present time in Australia (1992) there exists no undergraduate training for dental students in auxiliary utilisation. The result of this is that new dental graduates have no understanding of the concept of practicing sit-down four-handed dentistry in a comfortable and efficient manner. This compares with the United States of America (USA) where, since 1961, every dental student receives formal instruction in Dental Assistant Utilisation (DAU) and, since 1973, Training in Expanded Auxiliary Management. In this treatise the history and development of “four-handed dentistry” is presented along with a literature review of the fundamental principles of DAU. The intial pilot programmes and the subsequent federally funded national DAU programme in the USA are analysed. Four undergraduate DAU programmes from the USA and the current graduate continuing education DAU programme at Westmead Hospital Dental Clinical School are examined. Finally, guidelines for the establishment and operation of a DAU programme are outlined. The aim of this treatise therefore, is to provide the necessary information for a thorough understanding of the fundamentals and philosophy of Dental Assistant Utilisation. This information is presented in the hope that at some stage in the future training in assistant utilisation would become an integral and important part of the undergraduate dental curriculum in Australia. The purpose of this would be to fill a major void that currently exists in the undergraduate training of dental students in auxiliary utilisation.
109

Modelling of Auxiliary Devices for a Hardware-in-the-Loop Application / Modellering av hjälpaggregat för en hardware-in-the-loop-applikation

Olsén, Johan January 2005 (has links)
<p>The engine torque is an important control signal. This signal is disturbed by the devices mounted on the belt. To better be able to estimate the torque signal, this work aims to model the auxiliary devices'influence on the crankshaft torque. Physical models have been developed for the air conditioning compressor, the alternator and the power steering pump. If these models are to be used in control unit function development and testing, they have to be fast enough to run on a hardware-in-the-loop simulator in real time. The models have been simplified to meet these demands. </p><p>The compressor model has a good physical basis, but the validity of the control mechanism is uncertain. The alternator model has been tested against a real electronic control unit in a hardware-in-the-loop simulator, and tests show good results. Validation against measurements is however necessary to confirm the results. The power steering pump model also has a good physical basis, but it is argued that a simple model relating the macro input-output power could be more valuable for control unit function development.</p>
110

Functions of REP27 and the low molecular weight proteins PsbX and PsbW in repair and assembly of photosystem II

Garcia Cerdan, Jose Gines January 2009 (has links)
Oxygenic photosynthesis is the major producer of both oxygen and organic compounds on earth and takes place in plants, green algae and cyanobacteria. The thylakoid membranes are the site of the photosynthetic light reactions that involve the concerted action of four major protein complexes known as photosystem II (PSII), cytochrome b6f complex, ATP synthase and photosystem I (PSI). The function of PSII is of particular interest as it performs the light–driven water splitting reaction driving the photosynthetic electron transport. My thesis addressed different aspects of PSII assembly and the functions of its low molecular weight PSII subunits PsbX and PsbW. Photosynthesis in green algae and higher plants is controlled by the nucleus. Many proteins of nuclear origin participate in the regulation of the efficient assembly of the photosynthetic protein complexes. In this investigation we have identified one of these nuclear encoded auxiliary proteins of photosystem II, REP27, which participates in the assembly of the D1 reaction center protein and repair of photodamaged PSII in the green algae Chlamydomonas reinhardtii. Interestingly, PSII is specially enriched in Low Molecular Weight (LMW) subunits that have masses less than 10kDa. These proteins account for more than the half of the PSII subunits. Several questions remains poorly understood regarding the LMW: Which is their evolutionary origin? What function do they perform in the protein complex? Where are they located in the protein structure? In this investigation the functions of two of these LMW subunits (PsbX and PsbW) have been studied using antisense inhibition and T-DNA knockout mutant plants in Arabidopsis thaliana. Deficiency of the PsbX protein leads to impaired accumulation and functionality of PSII. Characterization of PsbW knock-out plants show that PsbW participates in stabilization of the macro-organization of PSII and the peripheral antenna (Light Harvesting Complex, LHCII) in the grana stacks of the chloroplast, also known as PSII-LHCII supercomplexes.

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