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Biogeography and evolution of Melanesian and South Pacific antsMATOS MARAVÍ, Pável Fortunato January 2016 (has links)
This thesis investigates the systematics, biogeography, and diversification dynamics of a large and ecologically important insect group in SE Asia and the Indo-Pacific region: the ants. This study utilizes a multidisciplinary framework to elucidate the evolutionary history of selected ant clades with the overall aim to shed light on similar ecological and evolutionary processes intervening in ant diversity.
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Diversification and Systemic Risk: A Financial Network PerspectiveFrey, Rüdiger, Hledik, Juraj January 2018 (has links) (PDF)
In this paper, we study the implications of diversification in the asset portfolios of banks
for financial stability and systemic risk. Adding to the existing literature, we analyse this issue in
a network model of the interbank market. We carry out a simulation study that determines the
probability of a systemic crisis in the banking network as a function of both the level of diversification,
and the connectivity and structure of the financial network. In contrast to earlier studies we find that
diversification at the level of individual banks may be beneficial for financial stability even if it does
lead to a higher asset return correlation across banks.
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Rádio, consensos e dissensos : o reverso do discurso e a crise da especialização agrícola (extremo oeste do Paraná 1980-2000) /Schlosser, Marli Terezinha Szumilo. January 2005 (has links)
No estudo em questão, objetivou-se analisar a construção discursiva presente na programação da Rádio Difusora do Paraná, no processo de modernização, especialização e diversidade agrícola no Extremo Oeste paranaense, mais especificamente no município de Marechal Cândido Rondon. O recorte temporal abrangeu o período de 1980-2000. A construção deste estudo foi norteada pela análise das fontes jornalísticas, não na condição de como a diversificação aconteceu, e acontece, e, sim, como uma instituição que se chama Rádio Difusora do Paraná, através de dois programas - Frente Ampla de Notícias (FAN) e Personalidade da Semana (PS), contribuiu na construção de discursos e representações referentes à agricultura. Para essa construção, participaram os atores (personalidades), através das quais surgiram conceitos, temas em torno do trabalho, agricultura, maquinário, clima, meio ambiente, cooperativismo e outros. Em suma, tratou-se de uma construção simbólica do agrário moderno. / The present study had the goal of analyzing the discursive construction present in the programming of Rádio Difusora do Paraná, in the process of modernization, specialization and agricultural diversification in the Far West of Paraná, more specifically in the municipal district of Marechal Cândido Rondon. The time frame ranged from 1980 to 2000. The construction of this study was guided by the analysis of the journalistic sources, not in the condition of how the diversification happened and happens, but how an institution that is called Rádio Difusora do Paraná, through two programs - Wide Front of News (FAN) and Personality of the Week (PS), contributed to the construction of speeches and representations referring to agriculture. The actors (personalities) participated in this construction, through which concepts, themes around the work, agriculture, machinery, weather, environment, cooperativism and others emerged. In short, it was a symbolic construction of the modern agrarian. / Orientador: Antônio Thomaz Júnior / Coorientador: Valdir Gregory / Banca: Jairo Gonçalves Melo / Banca: Marcos Aurélio Saquet / Banca: Eliane Tomiasi Paulino / Banca: Julio César Suzuki / Doutor
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Revenue Strategies of US States under Conditions of Economic and Political Stress: Revenues Diversification 1980 to 2011January 2013 (has links)
abstract: This dissertation assesses the impact of revenue diversification on state revenue growth and volatility and then, the economic, political and institutional factors that predict diversification. Previous studies, taking advice from modern portfolio theory, argue that diversifying a revenue portfolio can stabilize volatility and even lead to faster rates of growth over time. However, levels of diversification are not assigned randomly. Rather, differences among states in diversification might be a consequence of differences in states such as electoral cycles and the presence and strictness of tax limitations. Thus, the research question is: Whether or to what extent has diversification increased revenue growth and decreased volatility when the endogeneity of diversification is considered? Using two-stage least squares and fixed-effects regression models with the data of the 50 states from 1980 to 2011, I examined the impact of diversification, reflecting a state's own political and institutional characteristics (i.e., endogeneity), on growth and volatility. I found diversification was positively related to growth, but a diversified portfolio does not smooth volatility. Furthermore, I found that the level of revenue diversification increased in each year of legislators' terms and decreased in every year of governors' terms. These findings imply that legislators and governors have different preferences for diversification, perhaps due to different opportunities to enhance their reelection prospects. I then investigated the relationship between political leaders' year of the terms and changes in specific revenue sources, the biggest set of reelection opportunities. Selective sales and income taxes were negatively related to every year of legislators' terms. General sales taxes, corporate income taxes, and charges are positively related to every year of governors' terms. The results suggest that legislators focus on their districts or specific interest groups, closely associated with selective sales taxes. In contrast, governors' constituency-driven preferences lead them to be responsible for broader issues such as balancing the state budget, thereby using general sales taxes and charges as methods to do so. As a consequence of these political factors, levels of diversification will change, thereby influencing revenue growth and volatility. / Dissertation/Thesis / Ph.D. Public Administration 2013
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Pequenos mamíferos não voadores (Mammalia: Didelphimorphia e Rodentia) do baixo rio Xingu / Nonvolant mammals (Mammalia: Didelphimorphia and Rodentia) of the lower Xingu riverLeandro Perez Godoy 22 May 2015 (has links)
A região amazônica se destaca como a área de floresta tropical mais extensa e diversa do mundo. Essa diversidade é especialmente válida para os pequenos roedores e marsupiais que compõem o grupo mais diversificado de mamíferos Neotropicais, com estimativas de ocorrência de cerca de 107 espécies, sendo 91 endêmicas deste bioma. No entanto, nosso conhecimento sobre os limites específicos e geográfico destas espécies, bem como sua origem ainda está em sua infância. Diversas hipóteses buscam explicar essa a origem desta diversidade, sendo a dos rios como barreiras geográficas uma interpretação de diversificação para esta região, especialmente em grandes rios como o Xingu, que tem seu curso reto e seus tributários fluindo por um declive íngreme do norte do Escudo Brasileiro. Nesse contexto, o presente trabalho teve o objetivo de elaborar uma lista detalhada das espécies de pequenos mamíferos não voadores da região do baixo rio Xingu e discutir aspectos biogeográficos desse grupo para a Bacia Amazônica. Foram analisados aproximadamente 320 indivíduos obtidos através de visitas a coleções zoológicas e provenientes do Programa de Monitoramento, Resgate e Aproveitamento Científico da Fauna da Usina Hidrelétrica de Belo Monte. Foram realizadas análises quali- e quantitativas de características externas e crânio-dentárias, e moleculares, através do sequenciamento dos genes mitocondriais citocromo b e citocromo c oxidase subunidade I. A lista é composta por 35 espécies, sendo 16 marsupais didelfimorfos, 12 roedores sigmodontíneos e sete roedores equimídeos. Para todas elas são apresentadas informações sobre localidade tipo, distribuição geográfica, identificação e comentários taxonômicos. A lista de espécies obtida para a região do baixo rio Xingu destaca-se pela expressiva riqueza com registros de espécies raras, como Glironia venusta, Gracilinanus emiliae, Marmosa lepida, Lonchothrix emiliae, Dactylomys dactylinus, Makalata didelphoides e Echimys chysurus, além da presença de quatro espécies possivelmente não descritas dos gêneros Neacomys, Oligoryzomys e Monodelphis. Uma análise de similaridade com base na riqueza do grupo alvo desse estudo demonstra que o leste da Amazônia é uma região biogeográfica distinta dentro bacia hidrográfica. Através das análises moleculares, verificou-se que o Rio Xingu não atua como agente primário de diversificação para a maioria das espécies que estão sob sua influência biogeográfica, mas sim como mantenedor de diversidade em vários níveis no leste da Amazônia. / The Amazon region stands out as the most extensive and diverse area of tropical rainforest in the world. This high diversity is especially true for the small rodents and didelphid marsupials, which compose the most diversified group of neotropical mammals, with estimates of nearly 107 species, 91 of those are endemic to this biome. However, our knowledge about the species limits and geographic distribution, as well as their origins are still in its infancy. Several hypotheses arouse to explain the Amazon diversity, and the riverine barrier seems appropriate as an interpretation of diversification for this region, especially for rivers like Xingu, which has a straight course and its tributaries flowing through a steep slope from the northern Brazilian Shield. In this context, this study aimed to present a detailed and commented list of the non-volant small mammals of the lower Xingu river region and discuss some biogeographic aspects of these groups across the Amazon Basin. I analyzed about 320 specimens obtained from zoological collections and from the \"Faunal Assessment, Rescue and Scientifical Using Program of UHE Belo Monte\" (Programa de Monitoramento, Resgate e Aproveitamento Científico da Fauna da Usina Hidrelétrica de Belo Monte). There were performed quali- and quantitative analyses of morphological traits from skin and skull, and molecular analyses, through sequencing of mitochondrial genes cytochrome b and cytochrome c oxidase subunit I. The commented list is composed by 35 species, being 16 didelphid marsupials, 12 sigmodontine rodents and seven echimyid rodents. For every species, is presented information about type locality, geographic distribution, identification and taxonomic remarks. The species list obtained here to the low Xingu river region stands out for its expressive richness with records of rare species, such as Glironia venusta, Gracilinanus emiliae, Marmosa lepida, Lonchothrix emiliae, Dactylomys dactylinus, Makalata didelphoides, Echimys chrysurus, besides the presence of four possibly undescribed species from the genera Neacomys, Oligoryzomys and Monodelphis. A similarity analysis based on the non-volant small mammal species composition shows the eastern Amazon as a distinct biogeographical region inside this basin. Regarding the molecular analysis, it was verified that the Xingu river does not act as a primary agent of diversification for most of the species under its biogeographic influence, but as a diversity support at many levels in the eastern Amazon.
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The roles of diet, speciation and extinction on the diversification of birds, and on the assembly of frugivory networks / Os papéis da dieta, especiação e extinção na diversificação de aves e na montagem de redes de frugivoriaGustavo Burin Ferreira 02 October 2017 (has links)
To understand how diversity varies through time and/or space we need to understand speciation and extinction dynamics, and ultimately which factors (biotic or abiotic) affect such dynamics. It has been argued that biological interactions play an important role on the diversification of organisms, but macroevolutionary studies have usually adopted a simple characterization of species interactions. On the other hand ecological studies usually focus on well-characterized interactions of very few species. A network approach can augment our understanding of the ecological roles played by different species but it still lacks an evolutionary perspective preventing us to fully understand how ecological interactions are assembled. Using the available phylogeny, dietary data for virtually all bird species (approximately 9965 species) and a large collection of frugivory net- works, we tested the effect of diet on the diversification of birds, and the relationship between ecological roles within interaction networks and diversification dynamics of frugivorous species. Lastly, using computational simulations, we assessed the per- formance of two state-of-the-art methods to estimate diversification rates using molecular phylogenies. We suggest that omnivory acts as macroevolutionary sink where its ephemeral nature is retrieved through transitions from other guilds rather than from omnivore speciation. We propose that these dynamics result from competition within and among dietary guilds, influenced by the deep-time availability and predictability of food resources. We also observed that in the temperate zone, lineages with high-paced evolutionary dynamics (e.g. higher turn- over rates) typically do not occupy central roles in frugivory net- works, and that these restrictions are modulated by water avail- ability/predictability. Lastly, we found that the two state-of-the art phylogenetic methods perform equally well in diversity de- cline scenarios when estimating current rates, but both fail to detect the true diversification trajectory when extinction rates vary in time. This dissertation contributes to the understanding of biotic and abiotic mechanisms driving both the diversification and the assembly of interaction networks, and also provides important information on the reliability of diversification rate estimates by current, widely used methods / Para entendermos como a biodiversidade varia no tempo e/ou no espaço precisamos entender a dinâmcia de especiação e extinção, e quais fatores (bióticos ou abióticos) afetam essa dinâmica. Acredita-se que as interações biológicas desempen- ham um papel importante na diversificação de organismos, porém estudos macroevolutivos usualmente adotam caracter- izações simples de interações entre espécies. Por outro lado, estudos ecológicos comumente focam na descrição detalhada de interações entre poucas espécies. Uma abordagem de re- des pode aumentar a compreensão dos papéis ecológicos de- sempenhados por diferentes espécies, mas a pouca ênfase em abordagens evolutivas em estudos de redes biológicas nos im- pedem de compreender completamente como essas redes são montadas. Usando a filogenia e dados de dieta disponíveis para virtualmente todas as espécies de aves (aprox. 9965 espécies), e uma grande coleção de redes de frugivoria, investigamos o efeito da dieta na diversificação de aves, e testamos a relação en- tre papéis ecológicos em redes de interação e a dinâmica da di- versificação de espécies frugívoras. Ainda, usando simulações computacionais, avaliamos a performance de dois métodos am- plamente utilizados para estimar taxas de diversificação usando filogenias moleculares. Sugerimos que onivoria atua como um ralo macroevolutivo, onde sua natureza efêmera é recuperada através de transições de outras guildas de dieta ao invés de através da especiação de espécies onívoras. Nós sugerimos que essa dinâmica resulta da competição intra- e entre guildas, in- fluenciada pela disponibilidade e previsibilidade de recursos em ampla escalas de tempo. Nós também observamos que em regiões temperadas, linhagens com uma dinâmica evolutiova mais rápida (maiores taxas de substituição de espécies) em geral não ocupam papéis centrais em redes de frugivoria, e que es- sas restrições são principalmente modificadas por disponibili- dade/previsibilidade hídricas. Por fim, observamos que ambos os métodos filogenéticos testados tem desempenho igualmente bom para estimar taxas atuais, porém ambos falham em detectar a trajetória da diversificação quando as taxas de extinção variam no tempo. Essa tese contribui para o conhecimento de mecanis- mos bióticos e abióticos que afetam tanto a diversificação quanto a montagem de redes de interação, e também provê informações importantes acerca da confiabilidade das estimativas de taxas de diversificação advindas dos métodos atuais amplamente utilizados
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A aplicabilidade da moderna teoria de portfólios em títulos de renda fixa internacionais / The application of the porfolio's theory in fixed income securities.Fabrício Caprio Macastropa 13 November 2006 (has links)
Segundo o artigo ?Effects of Financial Globalization on Developing Countries: Some Empirical Evidence?, publicado pelo Fundo Monetário Internacional em 17 de março de 2003, a globalização financeira, definida como o aumento dos fluxos de capitais e investimentos entre países, contribuiu para o desenvolvimento do mercado de títulos de renda fixa internacional. A grande necessidade de recursos financeiros para o pagamento de dívidas e investimentos em diversos setores produtivos faz com que os governos utilizem-se de captações externas. Neste contexto, investidores interessados na obtenção de retornos superiores, compram esses títulos, diversificam suas carteiras de investimento e usufruem dos rendimentos que estes possibilitam, sejam sob a forma de cupom e/ou ganhos de capital.O trabalho de Harry Markowitz (1952), ?Portfolio Selection?, cuja principal contribuição é a distinção entre a variabilidade do retorno de um ativo financeiro e seu impacto no risco de uma carteira de investimento, possibilita que, desde que se disponha de um conjunto de dados, constitua-se carteiras que forneçam o menor nível de risco para um determinado nível de retorno de investimento. Este estudo propõe investigar se o trabalho desenvolvido por Harry Markowitz em 1952 é aplicável entre o período de janeiro de 2004 e dezembro de 2005 na composição de carteiras diversificadas de investimento. Para este propósito, todos os títulos de dívida emitidos pelos governos americano, brasileiro, argentino, mexicano e venezuelano no exterior, em dólares americanos, com datas de emissão até dezembro de 2003 e vencimento superior a dezembro de 2005 foram extraídos do Euroclear Bank (?Clearing House?). Cotações e dados complementares foram obtidos do sistema de informações financeiras Bloomberg, auxiliando na filtragem dos dados. A aplicação de vários testes permitiu concluir que, em média, ao adicionar ativos de países considerados emergentes da América Latina, os portfolios apresentam retornos superiores. Testes sobre distribuição dos retornos históricos dos títulos de dívida emitidos pelo governo brasileiro foram realizados, encontrando-se que seguem uma distribuição normal. Alguns questionamentos surgiram durante o trabalho, como a influência do aumento da taxa básica de juros americana ?Fed Fund? sobre o retorno dos portfolios, a influência de legislações entre diferentes jurisdições, sendo objeto de estudos futuros. / According to the article ?Effects of Financial Globalization on Developing Countries: Some Empirical Evidence?, published by the International Monetary Fund on March 17, 2003, the financial globalization, defined as na increase in the capital and investment flows between countries, contributed to the development of the fixed income international market. Financial resources to the payment of debts and investments in several productive sectors conducted Governments to use externals funding. In this context, investors interested to obtain better returns, buy securities, diversify their portfolios and they can reach gains under the coupons they received and/or capital gain. The Markowitz?s job in 1952, entitled ?Portfolio Selection?, about the relation between risk and return was the great contribution to the Modern Finance Theory. The contribution laid down on the distinction between the variability of an asset return and the impact in the portfolio risk. Markowitz? articles showed how to reach a portfolio which provides the best relation between risk and return. This present study aim to investigate whether the Markowitz?s article is applicable between January 2004 and December 2005. For this purpose, all fixed income securities issued by the American, Brazilian, Argentinean, Mexican and Venezuelan, in US Dollars, issuance date up to December 2003 and maturity date higher than December 2005 were extracted from Euroclear Bank (?Clearing House?). Quotations and additional data were obtained from Bloomberg Financial Markets. Tests were conducted to assess the portfolios and, on average, when you add securities from emerging countries at Latin America, the portfolio has a better return at the same level of risk. Distribution tests on historical returns showed normality. Some questions could not be answered, in special on the influence of raising Fed Fund rates on portfolio returns and the influence of legislations in different jurisdictions, being subject for future articles.
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[en] TRANSIENT FAULT TOLERANCE BY DISTINCTNESS / [pt] TOLERANCIA A FALHAS TRANSIENTES POR DIVERSIFICAÇÃOALBERTO CLEMENTINO MESQUITA JUNIOR 05 November 2009 (has links)
[pt] Neste trabalho considera-se um sistema de computação geograficamente localizado, destinado ao controle de processos em tempo real. O trabalho tem como objetivo determinar uma política de tolerância a falhas transientes, bem como uma arquitetura de base para o sistema em questão, assim como dispendido para implementá-la.
Abordam-se os pontos chaves necessários a tolerância, os quais são a caracterização das falhas físicas e humanas, as funções de mascaramento, deteção e recuperação após falhas físicas.
O conceito de diversificação é considerado como uma alternativa à deteção e tolerância a falhas humanas (projeto), como também no que diz respeito a capacidade de fornecer uma deteção eficaz de falhas físicas em modo comum, pois proporciona uma independência entre os módulos redundantes quando uma mesma falha os atinge de forma idêntica.
São apresentados uma arquitetura de base e a forma selecionada de colocar em prática a diversificação: a emulação de um dos microprocessadores. / [en] This work consideres a geographically localized computerized control sustem. The aim is to determine a policy of tolerance to transient faults, a well as a basic architecture for the control system. A discussion of the allocated effort to implement it is included here.
They included the characterization of physical and human faults, masking, detection and recovery of physical faults.
The concept of distinctness is considered as an alternative to detection and toleranc3e to human faults and also with respect to the capability to provide an effective detection of physical faults of common mode. This approach provides an independing among redundant modules when the same fault affects them in an identical way.
This work presents a basic architecture which illustrates the use of the concept of distinctness, through the emulation of a microprocessor.
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Between Oil Pasts and Utopian Dreams: Making State and Economy in Oman’s Citizen Labor IndustrySteiner, Robin Thomas, Steiner, Robin Thomas January 2018 (has links)
With oil reserves dwindling, efforts to create a diversified, post-oil economy in Oman have focused on building the human capital of citizens and promoting a new entrepreneurial ‘work culture’ among Omani employees and entrepreneurs. In a context in which state-provided jobs represent both an exchange of labor for a salary and a means of securing a citizen’s rightful share of the nation’s oil revenues, issues of productivity and workforce development are most often framed in terms of the ‘mindset’ of individual citizens. Drawing on 16 months of ethnographic fieldwork with experts and professionals in Oman’s thriving citizen labor industry—the industry of human resource specialists, consultants, career coaches, entrepreneurship trainers, and the organizations which support and sponsor them—this dissertation explores how utopian investments in Omani human capital have shaped the distributive governance of the Omani state, the production of persons, and the making of ‘an economy.’ In an environment in which economic ‘growth’ is driven by state-guided subsidy rather than market mechanisms, this dissertation describes how economic and managerial expertise is employed to create 'an economy’ in ways that are largely unaccompanied by the production of markets. By doing so, this dissertation highlights how seemingly neoliberal interventions aimed at ‘rolling back’ the state and cultivating entrepreneurial ‘mindsets’ have counterintuitively produced subjects who understand their personal and social ‘development’ as pieces of a larger system of distributive rights and obligations that is as much social and political as it is economic. Ultimately, by demonstrating how subsidy-driven investments in Oman’s citizen workforce reproduce distributive arrangements, this dissertation complicates the assumption that ‘development’ is an antidote to Oman’s natural resource dependence.
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Microhabitat and Climatic Niche Change Explain Patterns of Diversification among Frog FamiliesMoen, Daniel S., Wiens, John J. 07 1900 (has links)
A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal). The first two factors have been tested separately in several studies, but the relative importance of all three is largely unknown. Here we explore the correlates of diversification among families of frogs, which collectively represent approximate to 88% of amphibian species. We assemble and analyze data on phylogeny, climate, and microhabitat for thousands of species. We find that the best-fitting phylogenetic multiple regression model includes all three types of variables: microhabitat, rates of climatic niche change, and climatic niche position. This model explains 67% of the variation in diversification rates among frog families, with arboreal microhabitat explaining approximate to 31%, niche rates approximate to 25%, and climatic niche position approximate to 11%. Surprisingly, we show that microhabitat can have a much stronger influence on diversification than climatic niche position or rates of climatic niche change.
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