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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.
151

A aplicabilidade da moderna teoria de portfólios em títulos de renda fixa internacionais / The application of the porfolio's theory in fixed income securities.

Macastropa, Fabrício Caprio 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.
152

Pequenos mamíferos não voadores (Mammalia: Didelphimorphia e Rodentia) do baixo rio Xingu / Nonvolant mammals (Mammalia: Didelphimorphia and Rodentia) of the lower Xingu river

Godoy, Leandro Perez 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.
153

Adaptation and Diversification in Bluebells (Mertensia spp., Boraginaceae)

Lin, Shang-Yao Peter 06 June 2019 (has links)
Examining the ecological processes generating evolutionary patterns is crucial to understanding how biodiversity arises and evolves. One of the most striking examples of evolutionary diversification is provided by the flowering plants (angiosperms) and their flowers. Pollinators are traditionally considered to be the most important selective agents and drivers of floral diversity. However, many angiosperms have a generalized floral morphology and are visited by a diverse and overlapping suite of pollinators, making it unclear how pollinators could have driven diversification in these taxa. In addition, flowers and plant reproductive success are likely to be influenced by factors other than pollinators, such as herbivores, precipitation, and temperature. These factors need to be considered along with pollinators in order to improve our understanding of angiosperm evolution and diversification. In my thesis, I focussed on the processes influencing adaptation and diversification in flowering plants in the genus Mertensia (Boraginaceae), which have relatively unspecialized flowers that attract a variety of nectar- and pollen-feeding insects. In Chapter One, I explored correlations among floral traits, vegetative traits, and flowering phenology across 12 Mertensia species. In Chapter Two, I assessed reproductive isolating barriers between related Mertensia species occurring in sympatry. In Chapter Three, I examined the ecological function of floral orientation in two Mertensia species with respect to pollinators and precipitation. First, across Mertensia species, I found that early-flowering species were shorter, produced fewer flowers, and occurred at higher altitudes than late-flowering species—suggesting a life-history trade-off between plant size and flowering phenology, as well as an altitudinal effect on both traits. Interspecific variation in floral traits was not strongly associated with variation in flowering phenology or plant size. Second, between sympatric M. brevistyla and M. fusiformis populations, I found weak reproductive isolating barriers and possible hybridization. Most pre-pollination barriers were weak, as the two Mertensia species shared similar habitats, flowering phenology, and pollinator assemblages. The two relatively strong barriers were floral (ethological and mechanical) isolation and post-pollination isolation: Pollinators transferred significantly more of a pollen analogue among conspecific than heterospecific plants in mixed-species arrays, and flowers yielded higher seed set when receiving conspecific rather than heterospecific pollen in hand-pollination experiments. Lastly, I found that floral orientation was more likely to be under selection by precipitation than by pollinators, in that paternal fitness (i.e., pollen germination) was reduced by contact with water and that pollinator-mediated selection via maternal fitness (i.e., seed set) was not detected. A more pendant floral orientation likely protects the relatively long and exposed anthers of M. fusiformis from rain, while the less pendant M. brevistyla does not require this protection because of its shorter, more concealed reproductive structures. Although I detected an effect of floral orientation on seed set, I was not able to identify the selective agents driving this effect. In summary, my results suggest that pollinators play a minor role in influencing floral adaptation and diversification in Mertensia. Instead, the dominant influences on the traits I examined appear to be life-history trade-offs, environmental conditions that vary along altitudinal gradients, and abiotic variables (e.g., precipitation). It is important to consider these factors and their influences on paternal and maternal fitness in order to gain a broader perspective on floral evolution in plants with generalized pollination systems.
154

The Invisible Threat of Welfare Loss for Private Nordic Investors: A study on diversification

Qvist Nilsson, Marcus, Flodin, Christopher January 2016 (has links)
This study investigates to what level private Nordic investors allocate capital to different types of assets, a phenomenon known as diversification. Additionally, it examines if the degree of diversification influences the investor’s economic welfare. To carry out this study, the authors of this paper took part of data containing information about 80,000 Nordic investors and their investments. This data was processed by a computer program to create a cross-sectional data set, enabling the authors to make conclusions about the average Nordic investor. The study shows that private Nordic investors succeed in their ability to diversify with respect to the total number of stocks, but that their investment choices cause their investments to be inefficient. The investor holds stocks highly correlated to one another, resulting in economic costs.
155

Regulatory mechanisms driving motor neuron functional diversification

Khan, Mudassar Nazar 24 April 2018 (has links)
No description available.
156

Filogenia, biogeografia e revisão taxonômica de Nycticalanthus Ducke e Spiranthera A.St.-Hil. (Rutaceae, Galipeeae) / Phylogeny, biogeography and taxonomic revision of Nycticalanthus Ducke and Spiranthera A.St.-Hil. (Rutaceae, Galipeeae)

Brito, Lilian de Andrade 05 December 2017 (has links)
Os gêneros Nycticalanthus (monotípico) e Spiranthera (quatro espécies), pertencentes à família Rutaceae, tribo Galipeeae, são semelhantes morfologicamente e possuem distribuição restrita à América do Sul. São predominantemente arvoretas ciófilas de florestas úmidas, exceto Spiranthera odoratissima, que possui hábito arbustivo savânico e é a espécie de distribuição mais ampla, com a maior variabilidade morfológica. Este estudo teve como objetivo investigar as relações de parentesco entre Nycticalanthus e Spiranthera e suas espécies, utilizando dados moleculares (região ETS do DNA nuclear e espaçador trnL-F do DNA plastidial), visando entender os processos subjacentes à sua diversificação e biogeografia, além de realizar uma revisão taxonômica do grupo. Baseado na filogenia obtida e nas características morfológicas compartilhadas entre as espécies de ambos os gêneros, muitas delas sinapomórficas, é proposta a sinonimização do gênero monotípico Nycticalanthus sob Spiranthera. A revisão taxonômica apresentada baseia-se em uma extensa análise morfológica do grupo, incluindo expedições a campo e estudo de espécimes de herbários, elaboração de chave de identificação, descrição e ilustrações das seis espécies reconhecidas, incluindo uma espécie nova de Iquitos, Peru, além de dados de distribuição geográfica, habitats e variabilidade morfológica de cada táxon / The genera Nycticalanthus Ducke (monotypic) and Spiranthera A.St.-Hil. (four species), belonging to Rutaceae, tribe Galipeeae, are morphologically similar and restricted to South America. They are mostly sciophyllous treelets from rainforests, except for Spiranthera odoratissima, the most widespread species, which is a shrub inhabiting savannic formations and showing the highest morphological variation. This study investigated the phylogenetic relationships between the two genera, and among their species as well, using molecular data (ETS from the nuclear DNA, and trnL-F spacer from the plastidial DNA), aiming at understanding the processes involved in their diversification and biogeographic history. I also studied the taxonomic circunscription of both genera (all species included) carrying out a taxonomic revision of them. Based on the phylogeny and morphological characteristics shared by the species of both genera (most of them synapomorphies), I have proposed the synonymization of the monotypic genus Nycticalanthus under Spiranthera. The taxonomic revision is based on extensive morphological analysis of the group, including collecting and observation during field trips, and study of herbarium specimens. I also present identification keys, descriptions and illustrations for all the six species, including a new one from Iquitos, Peru, as well as updated geographic distribution range, habitats, and discussion about the morphological variation of each taxon
157

Product diversification, symbiotic orientation and firm performance : a perspective of extended resource-based view of the firm

Liao, Fanwei 01 January 2008 (has links)
No description available.
158

Cultivo de girassol na safrinha no Oeste do Paraná: efeitos do espaçamento entre linhas e populações de plantas / Cultivation of sunflower in second season in the Western of Paraná: effects of the spacings and plant populations

Orlando, Auri Francisco 29 August 2008 (has links)
Made available in DSpace on 2017-07-10T17:37:34Z (GMT). No. of bitstreams: 1 Auri_Francisco_Orlando.pdf: 196980 bytes, checksum: 6cddf7536fa9b2995e937673a016d9dc (MD5) Previous issue date: 2008-08-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In order to study the effects of changes in the spacing between row and the plant population in the agronomic performance of sunflowers, grown in second season in the western region of Paraná, led to an experiment in the field of Experimental C. Vale - Cooperative Agroindustrial in Palotina - PR. Was evaluated, the hybrid MG2 in design of blocks at random with split plots, using four spacings (E1 = 0.90 m, E2 = 0.75 m, E3 = 0.60 m and E4 = 0.45 m) and four population (P1 = 27,000, P2 = 35,000, P3 = 43,000 and P4 = 51,000 plants ha-1) with four replications. It was evaluated: plants height (AP) stem diameter (DC), leaves dry mass (MFS), dry mass stem + petiole (MSPC), dry mass chapter (MSCAP), leaf area (AF), chapter diameter (DCAP), grains mass per chapter (MGCAP), degree of filling of the chapter (GECPA), mass of a thousand grains (MMG), productivity (PROD), content of oil (TO) and production of oil (DB). There was only interaction between people in the variable spacing and AP. For variables, MSF; MSCP; MSCAP; MGCAP; AF and TO, no significant difference was observed according to the variation of the population of sunflower plants. As for variables: DC; PC; GEC; MMG; MGCAP; PROD DB and there was reduction of all these in row with population increase of sunflower plants. The change in spacing between rows to influence the culture in a meaningful way only the GECAP being the lowest values observed in populations of plants intermediate (0.60 and 0.75 m). However, the spacing between rows of sowing not proved a limiting factor and can be changed depending on the machinery available for the operations of sowing and harvesting, however must be avoided high densities of plants in any spacing. / Com objetivo de estudar os efeitos da variação do espaçamento entre linhas e da população de plantas, nos componentes de produção do girassol, híbrido MG02, cultivado nos meses de fevereiro e março, período conhecido como safrinha, na região Oeste de Paraná, conduziu-se um experimento no Campo Experimental da C.Vale - Cooperativa Agroindustrial, em Palotina PR. Avaliou-se o híbrido MG2, em delineamento de blocos ao acaso com parcelas subdivididas, utilizando quatro espaçamentos (E1 = 0,90 m, E2 = 0,75 m, E3 = 0,60 m e E4 = 0,45 m) e quatro populações (P1 = 27.000, P2 = 35.000, P3 = 43.000 e P4 = 51.000 plantas ha-1) com quatro repetições. Avaliou-se: altura de plantas (AP), diâmetro de caule (DC), massa seca de folhas (MFS), massa seca de pecíolo + caule (MSPC), massa seca de capítulo (MSCAP), área foliar (AF), diâmetro de capítulo (DCAP), massa de grãos por capítulo (MGCAP), grau de enchimento do capítulo (GECPA), massa de mil grãos (MMG), produtividade (PROD), teor de óleo (TO) e produção de óleo (PO). Houve interação entre espaçamento e população na variável AP. Para as variáveis, MSF; MSCP; MSCAP; MGCAP; AF e TO, não foi observada diferença significativa em função da variação da população de plantas de girassol. Quanto às variáveis: DC; PC; GEC; MMG; MGCAP; PO e PROD houve redução de todas, em função do aumento da população de plantas de girassol. Ha variação do espaçamento entre linhas para a cultura influenciou de forma significativa apenas o GECAP sendo os menores valores observados nas populações de plantas intermediárias (0,60 e 0,75 m). Contudo, o espaçamento entre linhas de semeadura não mostrou ser um fator limitante, podendo ser alterado em função do maquinário disponível para as operações de semeadura e colheita, no entanto devem-se evitar altas densidades de plantas em qualquer espaçamento
159

Systematics, biogeography and studies of floral evolution in Gesneriaceae

Luna Castro, Javier Alejandro January 2017 (has links)
Understanding the processes that have affected the diversification of herbaceous plants is fundamental to understand how flowering plants evolve, how ecosystems form and to predict the effect of climate change and geological events in plant communities. Aiming to create a strong phylogenetic framework where biogeographic and morphological hypothesis can be tested a higher level dated phylogeny of Gesneriaceae was produced. Gesneriaceae is a good study group as it has variable floral morphology, a broad distribution throughout the tropics and subtropics - represented in all non-arid tropical and subtropical hotspots of biodiversity. There are evident differences between lineages in the numbers of species, and it is comparatively well studied compared with other asterid families. In this study a consolidated taxonomic hypothesis of Gesneriaceae is suggested based on a genus level phylogeny, the ages of the main lineages of the family are presented, the effect of geological events are explored, the geographic origin of lineages are suggested and an insight into the effect of floral morphology on the evolution of the family is given. Limiting the taxonomic scope and focusing on a single family should help us better understand how flowering plants diversify.
160

Ecological specialization drives rapid diversification in neotropical Adelpha butterflies: a phylogenomic approach

Ebel, Emily Rose 12 March 2016 (has links)
Adaptive radiations provide exceptional opportunities to examine the relationships between natural selection, adaptation, and speciation. Neotropical Adelpha butterflies may represent such a radiation, characterized by extraordinary breadth in host plant use and wing color patterns. In this study, we use genome-wide RAD markers to reconstruct the complex evolutionary history of Adelpha and the closely related temperate genus, Limenitis. Despite the presence of significant missing data, a variety of phylogenetic methods produce similar and highly supported trees. These well-resolved phylogenies allow for the identification of an ecologically important shift to a toxic host plant family, as well as the confirmation of rampant wing pattern mimicry throughout the genus. Taken together, our results support the hypothesis that the colonization of novel host plants represents a key evolutionary innovation that is fueling ongoing adaptive diversification within this large, phenotypically diverse butterfly radiation.

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