The microbial communities found in soils are inherently heterogeneous and often exhibit spatial variations on a small scale. Becker et al. (2006) investigate this phenomenon and present statistical analyses to support their findings. In this project, alternative statistical methods and models are considered and employed in a re-analysis of the data from Becker. First, parametric nested random effects models are considered as an alternative to the nonparametric semivariogram models and kriging methods employed by Becker to analyze patterns of spatial variation. Second, multiple logistic regression models are employed to investigate factors influencing microbial community structure as an alternative to the simple logistic models used by Becker. Additionally, the microbial community profile data of Becker were unobservable at several points in the spatial grid. The Becker analysis assumes that the data are missing completely at random and as such have relatively little impact on inference. In this re-analysis, this assumption is investigated and it is shown that the pattern of missingness is correlated with both metabolic potential and spatial coordinates and thus provides useful information that was previously ignored by Becker. Multiple imputation methods are employed to incorporate the information present in the missing data pattern and results are compared with those of Becker.

Cette thèse, portant sur le choix de localisation résidentielle des ménages, s’inscrit dans le cadre théorique de la microéconomie urbaine et de l’utilité aléatoire. Si l’approche des choix discrets reste la plus appropriée dans ce domaine, la difficulté réside dans l’adaptation de ce type de modèles au contexte spatial (autocorrélation spatiale, grand nombre d’alternatives de choix) d’une part, et dans la manière de définir l’échelle de désagrégation d’autre part. Pour ce faire, nous avons procédé en deux temps. Nous avons estimé un logit multinomial avec un échantillon aléatoire d’alternatives pour comprendre le processus de choix de localisation résidentielle, avant de tester l’apport d’une structure hiérarchique pour traiter les problèmes d’autocorrélation spatiale. Cela a aussi permis l’investigation d’une nouvelle méthode de correction des biais liés à l’échantillonnage d’alternatives dans le cas du modèle logit emboîté. En termes de résultats, nous avons montré que la qualité de l’environnement social est le facteur le plus déterminant, sans remettre en cause le poids toujours important de l’accessibilité à l’emploi. Au plan méthodologique, nous avons été en mesure de tester l’apport de l’utilisation d’un modèle logit emboîté pour analyser les choix de localisation de l’aire urbaine de Lyon. Cependant, nous n’avons pas pu dépasser la difficulté de séparer l’autocorrélation spatiale et entre les nids. Le calage du modèle de choix de localisation en 1999 et en 2007 a aussi permis de donner des éléments de réponse sur la transférabilité temporelle des modèles de choix de localisation et de questionner, dans les travaux futurs, le pouvoir prédictif d’un modèle de choix de localisation. / This thesis, focusing on the choice of residential location, is based on the theoretical framework of urban micro-economy and random utility. Though discrete choice modelling is the most appropriate in this field, the difficulty lies in choosing the appropriate model to the spatial context of residential location choice (spatial autocorrelation, large number of alternatives), on the one hand, and in the way of defining the spatial scale, on the other hand. For this purpose, we proceeded in two stages. We estimated a multinomial logit with random sampling of alternatives to understand the process of residential location choice before taking into account the spatial autocorrelation, and estimating a nested logit model. It also allowed to investigate the feasibility of applying a new method to correct biases of sampling alternatives in the case of nested logit model. In terms of results, we have shown that social environment are the most important determinants of residential location choice. Though job accessibility still weigh on household choice decision. In terms of methodology, we were able to test the feasibility of estimating a nested logit model with sampling of alternatives to analyze the choice of location of Lyon urban area. However, we could not overcome the difficulty of distinguishing spatial autocorrelation from nesting. The use of 1999 and 2007 databases to model residential location choice also helped to provide answers on the temporal transferability of location choice models and discuss in future work the predictive power of a location choice model.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-10-19T13:49:16Z No. of bitstreams: 1 2016 - Claudia Bezerra da Silva.pdf: 8032175 bytes, checksum: ef71dd2a0e7801e9000e116c822a3a00 (MD5) / Made available in DSpace on 2017-10-19T13:49:16Z (GMT). No. of bitstreams: 1 2016 - Claudia Bezerra da Silva.pdf: 8032175 bytes, checksum: ef71dd2a0e7801e9000e116c822a3a00 (MD5) Previous issue date: 2016-03-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / and investigate the circulation of this agent in dogs in the Itaguai microregion, Rio de Janeiro, Brazil, and dogs and ticks in two provinces of the island of Cuba, analyzing epidemiological aspects associated with infections caused by this bacterium in dogs. A new real-time polymerase chain reaction method (qPCR) was patterned to target the citrate synthase gene (gltA) for the identification of A. platys in naturally infected dogs. The primers and probe were designed to amplify a fragment of 84 base pairs based on gltA gene sequences of A. platys available in GenBank. 186 blood samples of dogs from Itaguai microregion, Rio de Janeiro, Brazil, were tested by qPCR. The same samples were tested by cytology and nested polymerase chain reaction (nPCR, 16S rDNA) to determine the performance of qPCR front of these techniques. 17.20% of the samples tested positive by qPCR were significantly more than that detected by nPCR (13.98%). The qPCR technique was more specific than cytology, due to false-positive results obtained by optical microscopy. The prevalence of A. platys in dogs from Itaguai microregion was 14.4%. Dogs less than six months, infested by ticks, that spend the most of the time restrict to domestic environment and without shelter are factors associated with infection by this hemoparasite in dogs in the study area. During research, A. platys held in Cuba, 100 blood samples were collected from residents dogs in four cities located in the provinces of Havana and Mayabeque. When inspecting the animals, found ticks were collected, identified and carefully grouped, forming a total of 49 pools. DNA extracted from blood samples from dogs and ticks were subjected nPCR (16S rDNA). Positive samples in nPCR were also subjected to conventional PCR (gltA gene), and the products were sequenced. Only the species Rhipicephalus sanguineus sensu lato was found in Cuban dogs and 10.2% (n=5/49) of these ticks added to 16.0% (n=16/100) dogs were considered positive for A. platys. All sequences analyzed of the gltA and 16S rDNA genes, respectively, showed a 99-100% identity with sequences from A. platys reported in other countries. Phylogenetic analysis showed two clusters defined for the 16S rDNA gene and three clusters defined for the gltA gene. Based on the gltA gene, the deduced amino acid sequence showed two points of non-synonymous mutations at positions 88 and 168 compared to the reference sequence DQ525687. A preliminary study on the epidemiological aspects associated with infection with A. platys showed no statistical association with the variables studied (p> 0.05). This study also to report the first evidence of A. platys in both dogs and ticks in Cuba also presents for the first time the development of a new qPCR method that contributes to the advancement of research involving A. platys. The epidemiological study in Brazil allowed us to identify significant factors in the occurrence of canine anaplasmosis, while in Cuba, it can be concluded that more research is needed to assess what the deciding factors in the transmission and spread of A. platys in that country. / platys, e investigar a circula??o deste agente em c?es na microrregi?o de Itagua?, Rio de Janeiro, Brasil, e c?es e carrapatos em duas prov?ncias da ilha de Cuba, analisando aspectos epidemiol?gicos associados ? infec??o causada por esta bact?ria em c?es. Um novo m?todo de rea??o em cadeia da polimerase em tempo real (qPCR) foi padronizado com alvo no gene citrato sintase (gltA) para a identifica??o de A. platys em c?es naturalmente infectados. Os oligoiniciadores e a sonda foram desenhados para amplificar um fragmento de 84 pares de base baseado em sequ?ncias do gene gltA de A. platys dispon?veis no GenBank. 186 amostras de sangue de c?es da microrregi?o de Itagua?, Rio de Janeiro, Brasil, foram testados pela qPCR. As mesmas amostras foram testadas pela citologia e rea??o em cadeia da polimerase nested (nPCR, 16S rDNA) para determinar o desempenho da qPCR frente ? essas t?cnicas. 17,20% das amostras testadas pela qPCR foram positivas, significativamente mais do que detectado pela nPCR (13,98%). A t?cnica de qPCR foi mais espec?fica que a citologia, em virtude dos resultados falsopositivos obtidos pela microscopia ?ptica. A preval?ncia de A. platys em c?es da microrregi?o de Itagua? foi de 14,4%. C?es com menos de seis meses, infestados por carrapatos, que possam maior tempo restrito ao ambiente dom?stico e sem abrigo s?o fatores associados a infec??o por este hemoparasito em c?es na regi?o do estudo. Durante investiga??o de A. platys realizada em Cuba, 100 amostras de sangue foram coletadas de c?es residentes em quatro cidades localizadas nas prov?ncias de Habana e Mayabeque. Ao inspecionar os animais, carrapatos encontrados foram coletados, identificados e criteriosamente agrupados, formando um total de 49 pools. Amostras de DNA extra?das do sangue dos c?es e de carrapatos foram submetidas a nPCR (16S rDNA). Amostras positivas na nPCR foram tamb?m submetidas a PCR convencional (gene gltA), e os produtos foram sequenciados. Somente a esp?cie Rhipicephalus sanguineus sensu lato foi encontrada em c?es cubanos, e 10,2% (n=5/49) desses carrapatos somado aos 16,0% (n=16/100) de c?es foram considerados positivos para A. platys. Todas as sequ?ncias analisadas dos genes gltA e 16S rDNA, respectivamente, mostraram uma identidade de 99-100% com sequ?ncias de A. platys reportadas em outros pa?ses. A an?lise filogen?tica mostrou dois clusters definidos para o gene 16S rDNA e tr?s clusters definidos para o gene gltA. Com base no gene gltA, a sequ?ncia de amino?cidos deduzidos demonstrou dois pontos de muta??es n?o-sin?nimas nas posi??es 88 e 168 comparados com sequ?ncia de refer?ncia DQ525687. Um estudo preliminar sobre os aspectos epidemiol?gicos associados com a infec??o por A. platys demonstrou nenhuma associa??o estat?stica com as vari?veis avaliadas (p > 0,05). O presente estudo al?m de relatar a primeira evid?ncia de A. platys em ambos c?es e carrapatos em Cuba, tamb?m apresenta pela primeira vez o desenvolvimento de um novo m?todo de qPCR que contribui para o avan?o da pesquisa envolvendo A. platys. O estudo epidemiol?gico realizado no Brasil permitiu identificar fatores importantes na ocorr?ncia da anaplasmose canina, enquanto em Cuba, pode-se concluir que mais investiga??es s?o necess?rias para avaliar quais os fatores decisivos na transmiss?o e dispers?o de A. platys nesse pa?s.

Xanthomonas citri subsp. malvacearum é o agente causal da mancha angular do algodoeiro, uma importante doença reportada em áreas de produção no Brasil e em todo o mundo. A partir da análise comparativa de sequências parciais do gene rpoB de linhagens de X. citri subsp. malvacearum, X. campestris pv. campestris, X. axonopodis pv. axonopodis e X. citri subsp. citri, desenhou-se o par de primers xam1R/2R. Foram testadas 19 espécies pertencentes ao gênero Xanthomonas, além de bactérias dos gêneros Acidovorax, Burkholderia, Erwinia, Pseudomonas e Ralstonia, e o produto de PCR específico de aproximadamente 560 pares de bases foi observado apenas para linhagens de X. citri subsp. malvacearum. Os primers desenhados mostraram-se altamente sensíveis, apresentando níveis de detecção de 8 ufc/ 5,0 L para suspensões da cultura pura da bactéria e 1,0 ng de DNA genômico de X. citri subsp. malvacearum. No isolamento, a partir de amostras de sementes sabidamente contaminadas, foram obtidas colônias bacterianas com características de morfologia e coloração semelhantes à X. citri subsp. malvacearum. Esses isolados foram submetidos a testes de coloração de Gram, hidrólise de amido, reação de hipersensibilidade (HR) em folhas de fumo e tomateiro, testes de patogenicidade em plantas de algodoeiro, amplificação com os primers específicos desenhados e sequenciamento do fragmento obtido e os resultados obtidos confirmaram a identificação dos mesmos como X. citri subsp. malvacearum. Experimentos combinados de BIO-PCR/nested-PCR foram realizados a partir do material obtido do processo de extração do patógeno das sementes contaminadas utilizando-se na primeira etapa de amplificação os primers correspondentes à parte do gene rpoB e na segunda etapa o produto da primeira amplificação e os primers específicos xam1F/2R. O resultado foi a observação de uma banda de aproximadamente 560 pb correspondente ao fragmento específico de X. citri subsp. malvacearum para todas as amostras testadas. Neste trabalho foi desenvolvido um teste de PCR específico para a detecção e identificação rápida e precisa dessa bactéria em amostras de sementes de algodoeiro. / Xanthomonas citri subsp. malvacearum is the causal agent of angular leaf spot of cotton an important disease reported in production areas in Brazil and worldwide. From the comparative analysis of partial rpoB gene sequences of X. citri subsp. malvacearum, X. campestris pv. campestris, X. axonopodis pv. axonopodis and X. citri subsp. citri strains, the pair of primers xam1F/2R was designed. Nineteen species of the genus Xanthomonas and isolates of the genera Acidovorax, Burkholderia, Erwinia, Pseudomonas and Ralstonia were tested and the specific PCR product of about 560 base pairs was observed only for strains of X. citri subsp. malvacearum. The primers were highly sensitive, with detection levels of 8 cfu/ 5.0 L for suspensions of pure culture of bacteria and 1.0 ng of genomic DNA of X. citri subsp. malvacearum. From contaminated seed samples, bacterial colonies were obtained with characteristic morphology and coloration similar to X. citri subsp. malvacearum. These isolates were tested for Gram stain, starch hydrolysis, hypersensitivity reaction (HR) on tobacco and tomato leaves, pathogenicity tests on cotton plants, amplification with the specific primers designed and sequencing of the fragment obtained. The results confirmed their identification as X. citri subsp. malvacearum. PCR experiments in combination of BIOPCR/ nested-PCR were performed with the material obtained from the extraction process of pathogen from seeds using in the first step of amplification primers corresponding to part of the rpoB gene and the second step the product of the first amplification and the specific primers xam1F/2R. The result was a band of approximately 560 bp corresponding to the specific fragment of X. citri subsp. malvacearum for all samples tested. In this work, a PCR test for the quick detection and accurate identification of this bacterium in seed samples of cotton were developed.

In this collection of papers I have summarized my investigations into the field of evolutionary genetics and more specifically into patterns of biodiversity and evolutionary processes. The lizards (and frogs) studied here share common features in that they are largely present in unique environments, which are also regions that are biologically understudied. Most of these taxa show high degrees of endemism, interesting natural history characteristics, and each group manifests distinctive adaptations of general evolutionary interest. My work in the genus Telmatobius has been a progressive approach that began in my MS program, and it first focused on alpha taxonomy, morphological variation, and species boundaries. This work led to new studies initiated and completed at BYU involving further taxonomic revision (Formas et al., 2003; Chapter 1), and then revisiting and re-evaluating species boundaries established earlier (with allozyme markers) and this time with population level molecular (mitochondrial DNA) markers (Chapter 2). Our results indicate that the striking differences in size, coloration and general appearance in the various Lake Titicaca morphotypes are not genetically based. Further, there is evidence that these morphotypes have evolved very rapidly after demographic bottlenecks eroded present genetic variability. Telmatobius frogs of Lake Titicaca are listed by the International (IUCN) as critically endangered. We support this classification and further suggest studies to explore open questions like the possibility of adaptation along ecological resource gradients. Lizards of the genus Microlophus are interesting but for different reasons, and studies of this group constitutes the bulk of my dissertation work. The genus includes both Galapagos insular species, and continental taxa distributed in a linear gradient along > 4000 km of the western coast of South America. In studying Microlophus I first tackled the unresolved phylogenetic relationships within the genus (Chapter 3) and then pay attention to phylogeographic aspects of the most speciose lizard radiation in the Galapagos Archipelago (Chapter 4). Chapter 3 is a single manuscript provisionally accepted in the journal Systematic Biology. This paper introduces the lizard genus Microlophus (“lava lizards”) as a study system, and includes a large nuclear data set accompanied by an equally large mitochondrial data set (7877 characters in total). This paper explicitly differentiates among sequence alignments of gene regions that vary in tempo and class of mutational events. We show that this recognition is important and we suggest ways to appropriately deal with the alignment of multi-locus non-coding DNA data sets. A secondary finding in this study is that mtDNA and nDNA topologies are discordant with each other but that both are strongly supported, and that the nuclear topology is concordant with species distribution patterns along coastal South America. We hypothesize that in this particular region of the tree, the nuclear genome recovers a topology that is closer to the species tree, and conflicts occur due to likely secondary contact of distantly related taxa, suggesting that unique taxonomic relationships in the mtDNA gene tree are the result of hybridization. This last point highlights the value of dense taxonomic and character sampling for teasing apart different aspects of evolutionary processes. Chapter 4 is a manuscript to be submitted to the journal Evolution; in this study we further investigate the most speciose radiation of Microlophus in the Galapagos, based on an unparalleled sampling of most islands and small islets in the Archipelago. We use mtDNA sequences to both test hypothesized between-island colonization routes, as well as the expectation that within-island phylogeographic structure should be greater on older islands. Our mtDNA gene tree is strongly supported and allows rejection of previous alternatives, and we propose a novel sequence of between-island colonization events. Our results also reject the idea of phylogeographic structure been related solely to island age. Instead, we provide evidence to suggest that active volcanism as a major player in the generation of genetic diversity in within-island environments, and this is further compounded by the seemingly stochastic nature of within-island long-distance colonization routes mediated by ocean currents. We suggest that the direction and intensity of these currents, as currently understood, are insufficient to generate a priori hypotheses of oceanic colonization routes and their influence on gene flow. We do show that the standard stepping-stone model of migration, where genetic interchange is only possible among neighboring localities, does not explain much of the within-island population genetic structure unraveled by this study. From a biological conservation perspective the study of patterns of recent evolutionary history in the Galapagos provides with a window to evolutionary processes that have shaped and continue to impact the generation of biodiversity in the Galapagos Archipelago. Islands have long been viewed as natural laboratories of evolutionary change, and thus all island isolates are or could be distinctly important components of the larger, archipelago-wide processes. We provide working hypotheses for some of the demographic processes that might be generating within- and between-island biodiversity in this clade of lizards; confirmation of these explanations with independent data will have management implications for conserving the unique patterns observed in the Galapagos biota, but also the processes that generated these patterns.

Travel demand Management (TDM) focuses on improving the efficiency of the transportation system through changing traveler's travel behavior rather than expanding the infrastructure. An employer based integrated TDM program generally includes strategies designed to change the commuter's travel behavior in terms of mode choice, time choice and travel frequency. Research on TDM has focused on the evaluation of the effectiveness of TDM program to report progress and find effective strategies. Another research area, identified as high-priority research need by TRB TDM innovation and research symposium 1994 [Transportation Research Circular, 1994], is to develop tools to predict the impact of TDM strategies in the future. These tools are necessary for integrating TDM into the transportation planning process and developing realistic expectations. Most previous research on TDM impact evaluation was worksite-based, retrospective, and focused on only one or more aspects of TDM strategies. That research is generally based on survey data with small sample size due to lack of detailed information on TDM programs and promotions and commuter travel behavior patterns, which cast doubts on its findings because of potential small sample bias and self-selection bias. Additionally, the worksite-based approach has several limitations that affect the accuracy and application of analysis results. Based on the Washington State Commute Trip Reduction (CTR) dataset, this dissertation focuses on analyzing the participation rates of compressed work week schedules and telecommuting for the CTR affected employees, modeling the determinants of commuter's compressed work week schedules and telecommuting choices, and analyzing the quantitative impacts of an integrated TDM program on individual commuter's mode choice. The major findings of this dissertation may have important policy implications and help TDM practitioners better understand the effectiveness of the TDM strategies in terms of person trip and vehicle trip reduction. The models developed in this dissertation may be used to evaluate the impacts of an existing TDM program. More importantly, they may be incorporated into the regional transportation model to reflect the TDM impacts in the transportation planning process.

Cryptography is of fundamental importance to guarantee the security of communications, from the point-to-point transmission of messages and documents to the storage of big sets of data on cloud providers. As an example, we can use encryption, message authentication codes, and digital signatures to help us guarantee the privacy, integrity, and authenticity of data that is stored and/or transmitted. Many cryptographical solutions have a Boolean outcome, for example, the message is either authentic and accepted as it is, or it is not and so it needs to be rejected/re-transmitted. This outcome may be acceptable in scenarios where we can easily re-transmit the message, but it can pose a challenge when we deal with a large amount of data or a more sensitive content in which changes need to be further explored. In this context, this thesis proposes solutions to provide fault tolerance to certain cryptographic problems that traditionally have an all-or-nothing outcome. Fault tolerance is application dependent. In the case of a digital signature of a doc- ument that has been later modified, a fault-tolerant scheme can ensure authenticity and further identify which parts of the document were modified. This approach can be used in data forensics to investigate cybercrime, or to create redactable signatures for the purpose of privacy. In the case of aggregation of signatures, we consider an aggregation of a set of signatures containing a few invalid signatures (in the traditional sense). A fault-tolerant scheme is able to identify which signatures are valid and which ones are invalid, instead of rejecting the whole set. Digital signatures and aggregation of digital signatures require fault tolerance to be ensured at the origin (signer algorithm and aggregation algorithm, respectively), rather than just at the destination (verification algorithm). For this rea- son, we focus on techniques from combinatorial group testing that are nonadaptive rather than adaptive. This is in contrast with other applications of group testing, such as batch verification of signatures, employed at the verifier’s end which allow both adaptive and nonadaptive solutions. In this work, we explore solutions for fault tolerance using techniques of identification of defective elements used in nonadaptive combinatorial group testing. More specifically, we use the well studied cover-free families (CFFs). A d-cover-free family d-CFF(t, n) is a set system with n subsets of a t-set, where the union of any d subsets does not contain any other. A d-CFF(t, n) allows for the identification of up to d defective elements in a set of n elements by performing only t tests (typically t ≪ n). In the literature, CFFs are used to solve many problems in cryptography. In this work, we explore different aspects of cover-free families in order to better approach fault tolerance problems. The problems we investigate can be divided into two categories: static problems (fixed size) and dynamic problems (increasing size). In the context of static problems, we consider modification-tolerant digital signature schemes, which allow the identification of modifica- tions in signed data using a d-CFF, and in some cases the correction of such modifications in order to retrieve the originally signed data. We also propose a generalization of the classical definition of a d-CFF to support variable cover-free property, followed by some constructions and potential applications in cryptography. For dynamic problems, we con- sider the application of fault-tolerant aggregation of signatures. This problem requires an ii infinite sequence of CFFs with increasing n, consequently increasing t, and potentially in- creasing d. In this context, we investigate monotone, nested, and embedding sequences of CFFs, and propose constructions using techniques from combinatorial design theory and finite fields. In constructing these families, we are concerned with their compression ratio. The compression ratio of a sequence of CFFs measures how slowly the number of tests grow with respect to the number of elements to be tested, which affects the overall efficiency of the method. We provide constructions of CFF sequences with different compression ratios, which depend on relations among the CFF parameters in the sequence and the type of sequence. Some of these sequences achieve the best possible compression ratio, which meets the best known upper bound. Monotone, nested and embedding sequences of CFFs can be used in any group testing problem that is dynamic in nature. We discuss various cryptographical applications that can benefit from these infinite sequences of CFFs.

It is desirable to reduce the potential threats that result from the variability of nature, such as droughts or heat waves that lead to food shortage, or the other extreme, floods that lead to severe damage. To prevent such catastrophic events, it is necessary to understand, and to be capable of characterising, nature's variability. Typically one aims to describe the underlying dynamics of geophysical records with differential equations. There are, however, situations where this does not support the objectives, or is not feasible, e.g., when little is known about the system, or it is too complex for the model parameters to be identified. In such situations it is beneficial to regard certain influences as random, and describe them with stochastic processes. In this thesis I focus on such a description with linear stochastic processes of the FARIMA type and concentrate on the detection of long-range dependence. Long-range dependent processes show an algebraic (i.e. slow) decay of the autocorrelation function. Detection of the latter is important with respect to, e.g. trend tests and uncertainty analysis. Aiming to provide a reliable and powerful strategy for the detection of long-range dependence, I suggest a way of addressing the problem which is somewhat different from standard approaches. Commonly used methods are based either on investigating the asymptotic behaviour (e.g., log-periodogram regression), or on finding a suitable potentially long-range dependent model (e.g., FARIMA[p,d,q]) and test the fractional difference parameter d for compatibility with zero. Here, I suggest to rephrase the problem as a model selection task, i.e.comparing the most suitable long-range dependent and the most suitable short-range dependent model. Approaching the task this way requires a) a suitable class of long-range and short-range dependent models along with suitable means for parameter estimation and b) a reliable model selection strategy, capable of discriminating also non-nested models. With the flexible FARIMA model class together with the Whittle estimator the first requirement is fulfilled. Standard model selection strategies, e.g., the likelihood-ratio test, is for a comparison of non-nested models frequently not powerful enough. Thus, I suggest to extend this strategy with a simulation based model selection approach suitable for such a direct comparison. The approach follows the procedure of a statistical test, with the likelihood-ratio as the test statistic. Its distribution is obtained via simulations using the two models under consideration. For two simple models and different parameter values, I investigate the reliability of p-value and power estimates obtained from the simulated distributions. The result turned out to be dependent on the model parameters. However, in many cases the estimates allow an adequate model selection to be established. An important feature of this approach is that it immediately reveals the ability or inability to discriminate between the two models under consideration. Two applications, a trend detection problem in temperature records and an uncertainty analysis for flood return level estimation, accentuate the importance of having reliable methods at hand for the detection of long-range dependence. In the case of trend detection, falsely concluding long-range dependence implies an underestimation of a trend and possibly leads to a delay of measures needed to take in order to counteract the trend. Ignoring long-range dependence, although present, leads to an underestimation of confidence intervals and thus to an unjustified belief in safety, as it is the case for the return level uncertainty analysis. A reliable detection of long-range dependence is thus highly relevant in practical applications. Examples related to extreme value analysis are not limited to hydrological applications. The increased uncertainty of return level estimates is a potentially problem for all records from autocorrelated processes, an interesting examples in this respect is the assessment of the maximum strength of wind gusts, which is important for designing wind turbines. The detection of long-range dependence is also a relevant problem in the exploration of financial market volatility. With rephrasing the detection problem as a model selection task and suggesting refined methods for model comparison, this thesis contributes to the discussion on and development of methods for the detection of long-range dependence. / Die potentiellen Gefahren und Auswirkungen der natürlicher Klimavariabilitäten zu reduzieren ist ein wünschenswertes Ziel. Solche Gefahren sind etwa Dürren und Hitzewellen, die zu Wasserknappheit führen oder, das andere Extrem, Überflutungen, die einen erheblichen Schaden an der Infrastruktur nach sich ziehen können. Um solche katastrophalen Ereignisse zu vermeiden, ist es notwendig die Dynamik der Natur zu verstehen und beschreiben zu können. Typischerweise wird versucht die Dynamik geophysikalischer Datenreihen mit Differentialgleichungssystemen zu beschreiben. Es gibt allerdings Situationen in denen dieses Vorgehen nicht zielführend oder technisch nicht möglich ist. Dieses sind Situationen in denen wenig Wissen über das System vorliegt oder es zu komplex ist um die Modellparameter zu identifizieren. Hier ist es sinnvoll einige Einflüsse als zufällig zu betrachten und mit Hilfe stochastischer Prozesse zu modellieren. In dieser Arbeit wird eine solche Beschreibung mit linearen stochastischen Prozessen der FARIMA-Klasse angestrebt. Besonderer Fokus liegt auf der Detektion von langreichweitigen Korrelationen. Langreichweitig korrelierte Prozesse sind solche mit einer algebraisch, d.h. langsam, abfallenden Autokorrelationsfunktion. Eine verläßliche Erkennung dieser Prozesse ist relevant für Trenddetektion und Unsicherheitsanalysen. Um eine verläßliche Strategie für die Detektion langreichweitig korrelierter Prozesse zur Verfügung zu stellen, wird in der Arbeit ein anderer als der Standardweg vorgeschlagen. Gewöhnlich werden Methoden eingesetzt, die das asymptotische Verhalten untersuchen, z.B. Regression im Periodogramm. Oder aber es wird versucht ein passendes potentiell langreichweitig korreliertes Modell zu finden, z.B. aus der FARIMA Klasse, und den geschätzten fraktionalen Differenzierungsparameter d auf Verträglichkeit mit dem trivialen Wert Null zu testen. In der Arbeit wird vorgeschlagen das Problem der Detektion langreichweitiger Korrelationen als Modellselektionsproblem umzuformulieren, d.h. das beste kurzreichweitig und das beste langreichweitig korrelierte Modell zu vergleichen. Diese Herangehensweise erfordert a) eine geeignete Klasse von lang- und kurzreichweitig korrelierten Prozessen und b) eine verläßliche Modellselektionsstrategie, auch für nichtgenestete Modelle. Mit der flexiblen FARIMA-Klasse und dem Whittleschen Ansatz zur Parameterschätzung ist die erste Voraussetzung erfüllt. Hingegen sind standard Ansätze zur Modellselektion, wie z.B. der Likelihood-Ratio-Test, für nichtgenestete Modelle oft nicht trennscharf genug. Es wird daher vorgeschlagen diese Strategie mit einem simulationsbasierten Ansatz zu ergänzen, der insbesondere für die direkte Diskriminierung nichtgenesteter Modelle geeignet ist. Der Ansatz folgt einem statistischen Test mit dem Quotienten der Likelihood als Teststatistik. Ihre Verteilung wird über Simulationen mit den beiden zu unterscheidenden Modellen ermittelt. Für zwei einfache Modelle und verschiedene Parameterwerte wird die Verläßlichkeit der Schätzungen für p-Wert und Power untersucht. Das Ergebnis hängt von den Modellparametern ab. Es konnte jedoch in vielen Fällen eine adäquate Modellselektion etabliert werden. Ein wichtige Eigenschaft dieser Strategie ist, dass unmittelbar offengelegt wird, wie gut sich die betrachteten Modelle unterscheiden lassen. Zwei Anwendungen, die Trenddetektion in Temperaturzeitreihen und die Unsicherheitsanalyse für Bemessungshochwasser, betonen den Bedarf an verläßlichen Methoden für die Detektion langreichweitiger Korrelationen. Im Falle der Trenddetektion führt ein fälschlicherweise gezogener Schluß auf langreichweitige Korrelationen zu einer Unterschätzung eines Trends, was wiederum zu einer möglicherweise verzögerten Einleitung von Maßnahmen führt, die diesem entgegenwirken sollen. Im Fall von Abflußzeitreihen führt die Nichtbeachtung von vorliegenden langreichweitigen Korrelationen zu einer Unterschätzung der Unsicherheit von Bemessungsgrößen. Eine verläßliche Detektion von langreichweitig Korrelierten Prozesse ist somit von hoher Bedeutung in der praktischen Zeitreihenanalyse. Beispiele mit Bezug zu extremem Ereignissen beschränken sich nicht nur auf die Hochwasseranalyse. Eine erhöhte Unsicherheit in der Bestimmung von extremen Ereignissen ist ein potentielles Problem von allen autokorrelierten Prozessen. Ein weiteres interessantes Beispiel ist hier die Abschätzung von maximalen Windstärken in Böen, welche bei der Konstruktion von Windrädern eine Rolle spielt. Mit der Umformulierung des Detektionsproblems als Modellselektionsfrage und mit der Bereitstellung geeigneter Modellselektionsstrategie trägt diese Arbeit zur Diskussion und Entwicklung von Methoden im Bereich der Detektion von langreichweitigen Korrelationen bei.

This research focuses on the challenges and opportunities facing local governance agents in advancing an ecosystem approach to conceptualizing and governing community health in Norfolk County, Ontario. Norfolk County is a rural, agriculturally-based community dependent upon tobacco production. This industry has collapsed, triggering widespread socioeconomic impacts and community health pressures. The government is searching for alternative modes of economic development and tensions are high with respect to the direction and nature of these developments. Some citizens are concerned about the security of their rural livelihoods. Others are concerned about ecological integrity. Still others are convinced of the need for aggressive economic growth. Local decision-makers are struggling to meet all of these requirements. An ecosystem approach views health as part of the broader socio-ecological system, recognizing that health outcomes are by-products of complex biophysical, social, political and economic system interactions at nested spatial and temporal scales. The approach contrasts with conventional health models, which tend to be reactionary, narrowly focused, and short-sighted. Such models are typical of the hierarchical, technocratic nature of public administration which renders decision-making structures and processes ill equipped to deal with complex problems. More systemic, integrated, participatory and collaborative approaches to decision-making are needed in order to better address the complexities involved in facilitating healthy and sustainable community development. Additionally, governance agents must also be able to embrace and navigate these evolving approaches to health conceptualization and governance. An investigation into Norfolk County grounds this analysis by revealing the challenges and opportunities facing local governance agents in advancing an ecosystem approach. The case study research effectively tests the utility and feasibility of the ecosystem approach through a qualitative analysis. The research contributes criteria required for advancing an ecosystem approach to community health governance and practice and empirically tests them within the context of Norfolk County.

This research focuses on the challenges and opportunities facing local governance agents in advancing an ecosystem approach to conceptualizing and governing community health in Norfolk County, Ontario. Norfolk County is a rural, agriculturally-based community dependent upon tobacco production. This industry has collapsed, triggering widespread socioeconomic impacts and community health pressures. The government is searching for alternative modes of economic development and tensions are high with respect to the direction and nature of these developments. Some citizens are concerned about the security of their rural livelihoods. Others are concerned about ecological integrity. Still others are convinced of the need for aggressive economic growth. Local decision-makers are struggling to meet all of these requirements. An ecosystem approach views health as part of the broader socio-ecological system, recognizing that health outcomes are by-products of complex biophysical, social, political and economic system interactions at nested spatial and temporal scales. The approach contrasts with conventional health models, which tend to be reactionary, narrowly focused, and short-sighted. Such models are typical of the hierarchical, technocratic nature of public administration which renders decision-making structures and processes ill equipped to deal with complex problems. More systemic, integrated, participatory and collaborative approaches to decision-making are needed in order to better address the complexities involved in facilitating healthy and sustainable community development. Additionally, governance agents must also be able to embrace and navigate these evolving approaches to health conceptualization and governance. An investigation into Norfolk County grounds this analysis by revealing the challenges and opportunities facing local governance agents in advancing an ecosystem approach. The case study research effectively tests the utility and feasibility of the ecosystem approach through a qualitative analysis. The research contributes criteria required for advancing an ecosystem approach to community health governance and practice and empirically tests them within the context of Norfolk County.