835 resultados para Idealized model for theory development
Resumo:
Neonatal anoxia is a worldwide clinical problem that has serious and lasting consequences. The diversity of models does not allow complete reproducibility, so a standardized model is needed. In this study, we developed a rat model of neonatal anoxia that utilizes a semi-hermetic system suitable for oxygen deprivation. The validity of this model was confirmed using pulse oximetry, arterial gasometry, observation of skin color and behavior and analysis of Fos immunoreactivity in brain regions that function in respiratory control. For these experiments, 87 male albino neonate rats (Rattus norvegicus, lineage Wistar) aged approximate 30 postnatal hours were divided into anoxia and control groups. The pups were kept in an euthanasia polycarbonate chamber at 36 +/- 1 degrees C, with continuous 100% nitrogen gas flow at 3 L/min and 101.7 kPa for 25 min. The peripheral arterial oxygen saturation of the anoxia group decreased 75% from its initial value. Decreased pH and partial pressure of oxygen and increased partial pressure of carbon dioxide were observed in this group, indicating metabolic acidosis, hypoxia and hypercapnia. respectively. Analysis of neuronal activation showed Fos immunoreactivity in the solitary tract nucleus, the lateral reticular nucleus and the area postrema, confirming that those conditions activated areas related to respiratory control in the nervous system. Therefore, the proposed model of neonatal anoxia allows standardization and precise control of the anoxic condition, which should be of great value in indentifying both the mechanisms underlying neonatal anoxia and novel therapeutic strategies to combat or prevent this widespread public health problem. (C) 2011 Elsevier B.V. All rights reserved.
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The inclusion of the history of science in science curricula-and specially, in the curricula of science teachers-is a trend that has been followed in several countries. The reasons advanced for the study of the history of science are manifold. This paper presents a case study in the history of chemistry, on the early developments of John Dalton`s atomic theory. Based on the case study, several questions that are worth discussing in educational contexts are pointed out. It is argued that the kind of history of science that was made in the first decades of the twentieth century (encyclopaedic, continuist, essentially anachronistic) is not appropriate for the development of the competences that are expected from the students of sciences in the present. Science teaching for current days will benefit from the approach that may be termed the ""new historiography of science"".
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In this paper we construct and analyze a growth model with the following three ingredients. (i) Technological progress is embodied. (ii) The production function of a firm is such that the firm makes both technology upgrade as well as capital and labor decisions. (iii) The firm’s production technology is putty-clay. We assume that there are disincentives to the accumulation of capital, resulting in a divergence between the social and the private cost of investment. We solve a single firm’s problem in this environment. Then we determine general equilibrium prices of capital goods of different vintages. Using these prices we aggregate firms’ decisions and construct the theoretical analogues of National Income statistics. This generates a relationship between disincentives and per capita incomes. We analyze this relationship and show the quantitative and qualitative roles of embodiment and putty-clay. We also show how the model is taken to data, quantified and used to determine to what extent income gaps across countries can be attributed to disincentives.
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The objectives of this paper are twofold. First, it intends to provide theoretical elements to analyze the relation between real exchange rates and economic development. Our main hypothesis is very much in line with the Dutch disease literature, and states that competitive currencies contribute to the existence and maintenance of the anufacturing sector in the economy. This, in turn, brings about higher growth rates in the long run, given the existence of increasing returns in the industrial sector, and its importance in generating echnological change and increasing productivity in the overall economy. The second objective of this paper is empirical. It intends to analyze examples of successful exchange rate policies, such as Chile and Indonesia in the eighties, as a benchmark for comparison with countries where currency overvaluation has taken place, such as Brazil. In the latter case, the local currency is being inflated by large capital inflows, due to high domestic interest rates and to a boom in demand and prices of commodities in the international markets. It will be argued that the industrial sector bears most of the burden when the currency appreciates, and that Brazil risks at deindustrialization if there are no changes in the exchange rate regime
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This thesis develops and evaluates a business model for connected full electric vehicles (FEV) for the European market. Despite a promoting political environment, various barriers have thus far prevented the FEV from becoming a mass-market vehicle. Besides cost, the most noteworthy of these barriers is represented by range anxiety, a product of FEVs’ limited range, lacking availability of charging infrastructure, and long recharging times. Connected FEVs, which maintain a constant connection to the surrounding infrastructure, appear to be a promising element to overcome drivers’ range anxiety. Yet their successful application requires a well functioning FEV ecosystem which can only be created through the collaboration of various stakeholders such as original equipment manufacturers (OEM), first tier suppliers (FTS), charging infrastructure and service providers (CISP), utilities, communication enablers, and governments. This thesis explores and evaluates how a business model, jointly created by these stakeholders, could look like, i.e. how stakeholders could collaborate in the design of products, services, infrastructure, and advanced mobility management, to meet drivers with a sensible value proposition that is at least equivalent to that of internal combustion engine (ICE) cars. It suggests that this value proposition will be an end-2-end package provided by CISPs or OEMs that comprises mobility packages (incl. pay per mile plans, battery leasing, charging and battery swapping (BS) infrastructure) and FEVs equipped with an on-board unit (OBU) combined with additional services targeted at range anxiety reduction. From a theoretical point of view the thesis answers the question which business model framework is suitable for the development of a holistic, i.e. all stakeholder-comprising business model for connected FEVs and defines such a business model. In doing so the thesis provides the first comprehensive business model related research findings on connected FEVs, as prior works focused on the much less complex scenario featuring only “offline” FEVs.
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Este estudo buscou verificar a influencia dos agentes da cadeia de suprimentos no desempenho do desenvolvimento de novos produtos quando os agentes são analisados em conjunto. A motivação desta pesquisa veio de estudos que alertaram para a consideração da integração da cadeia de suprimentos como um constructo multidimensional, englobando o envolvimento da manufatura, fornecedores e clientes no desenvolvimento de novos produtos; e devido à falta de informação sobre as influencias individuais destes agentes no desenvolvimento de novos produtos. Sob essas considerações, buscou-se construir um modelo analítico baseado na Teoria do Capital Social e Capacidade Absortiva, construir hipóteses a partir da revisão da literatura e conectar constructos como cooperação, envolvimento do fornecedor no desenvolvimento de novos produtos (DNP), envolvimento do cliente no DNP, envolvimento da manufatura no DNP, antecipação de novas tecnologias, melhoria contínua, desempenho operacional do DNP, desempenho de mercado do NPD e desempenho de negócio do DNP. Para testar as hipóteses foram consideradas três variáveis moderadoras, tais como turbulência ambiental (baixa, média e alta), indústria (eletrônicos, maquinários e equipamentos de transporte) e localização (América, Europa e Ásia). Para testar o modelo foram usados dados do projeto High Performance Manufacturing que contém 339 empresas das indústrias de eletrônicos, maquinários e equipamentos de transporte, localizadas em onze países. As hipóteses foram testadas por meio da Análise Fatorial Confirmatória (AFC) incluindo a moderação muti-grupo para as três variáveis moderadoras mencionadas anteriormente. Os principais resultados apontaram que as hipóteses relacionadas com cooperação foram confirmadas em ambientes de média turbulência, enquanto as hipóteses relacionadas ao desempenho no DNP foram confirmadas em ambientes de baixa turbulência ambiental e em países asiáticos. Adicionalmente, sob as mesmas condições, fornecedores, clientes e manufatura influenciam diferentemente no desempenho de novos produtos. Assim, o envolvimento de fornecedores influencia diretamente no desempenho operacional e indiretamente no desempenho de mercado e de negócio em baixos níveis de turbulência ambiental, na indústria de equipamentos de transporte em países da Americanos e Europeus. De igual forma, o envolvimento do cliente influenciou diretamente no desempenho operacional e indiretamente no desempenho de mercado e do negócio em médio nível de turbulência ambiental, na indústria de maquinários e em países Asiáticos. Fornecedores e clientes não influenciam diretamente no desempenho de mercado e do negócio e não influenciam indiretamente no desempenho operacional. O envolvimento da manufatura não influenciou nenhum tipo de desempenho do desenvolvimento de novos produtos em todos os cenários testados.
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This paper aims to verify the main contributions and adjustments that the paper “Towards a Legal Theory of Finance” from Katharina Pistor may bring to the role of the Brazilian National Bank for Economic and Social Development (BNDES) in the Brazilian development financing. In order to do so, I work with two questions in this paper: (i) such theory presents elements which allow analyzing the role of the BNDES and from there, if it is required, adjustments can be made in the governance of the BNDES? and (ii) there are academics and scholars that, together with the theory, also contribute with the improvement of the BNDES role in the development of Brazil?
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Esta dissertação se propõe ao estudo de inferência usando estimação por método generalizado dos momentos (GMM) baseado no uso de instrumentos. A motivação para o estudo está no fato de que sob identificação fraca dos parâmetros, a inferência tradicional pode levar a resultados enganosos. Dessa forma, é feita uma revisão dos mais usuais testes para superar tal problema e uma apresentação dos arcabouços propostos por Moreira (2002) e Moreira & Moreira (2013), e Kleibergen (2005). Com isso, o trabalho concilia as estatísticas utilizadas por eles para realizar inferência e reescreve o teste score proposto em Kleibergen (2005) utilizando as estatísticas de Moreira & Moreira (2013), e é obtido usando a teoria assintótica em Newey & McFadden (1984) a estatística do teste score ótimo. Além disso, mostra-se a equivalência entre a abordagem por GMM e a que usa sistema de equações e verossimilhança para abordar o problema de identificação fraca.
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The following paper was conducted with the support of several entrepreneurs and startups from Brazil. The aim of the research was to find out which impact the Business Model Canvas, further abbreviated as BMC, has on technology-oriented startups in Brazil. The first step of the study was identify some general concepts of entrepreneurship, as well as the conditions and environment of the country. Afterwards, it was focused on defining and comparing different business model tools and concepts to the BMC. After the literature review and meeting with several professionals in the area of entrepreneurship and startups, a questionnaire was formulated in order to conduct the qualitative study and identify the main impact of the tool. The questionnaire was answered by ten startups. In order to check the validity and credibility of the research outcomes, theory and investigator triangulation was used. As a result, the usage of the BMC could be evaluated by obtaining the outcomes and the theory, which showed that Brazilian tech startups are using Osterwalder’s model for the reason of idea creation and testing, validating and pivoting their business model. Interestingly, the research revealed that the entrepreneurs are using the tool often not in the traditional way of printing it, but rather applying it as a thinking approach. Besides, the entrepreneurs are focusing mostly on developing a strong Value Proposition, Customer Segment and sustainable Revenue Streams, while afterwards the remaining building blocks are built. Moreover, the research showed that the startups are using also other concepts, such as the Customer Development Process or Build-Measure-Learn Feedback Loop. These methodologies are often applied together with the BMC and helps to identify the most sustainable components of the business idea. Keywords: Business
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This dissertation surveys the literature on economic growth. I review a substantial number of articles published by some of the most renowned researchers engaged in the study of economic growth. The literature is so vast that before undertaking new studies it is very important to know what has been done in the field. The dissertation has six chapters. In Chapter 1, I introduce the reader to the topic of economic growth. In Chapter 2, I present the Solow model and other contributions to the exogenous growth theory proposed in the literature. I also briefly discuss the endogenous approach to growth. In Chapter 3, I summarize the variety of econometric problems that affect the cross-country regressions. The factors that contribute to economic growth are highlighted and the validity of the empirical results is discussed. In Chapter 4, the existence of convergence, whether conditional or not, is analyzed. The literature using both cross-sectional and panel data is reviewed. An analysis on the topic of convergence using a quantile-regression framework is also provided. In Chapter 5, the controversial relationship between financial development and economic growth is analyzed. Particularly, I discuss the arguments in favour and against the Schumpeterian view that considers financial development as an important determinant of innovation and economic growth. Chapter 6 concludes the dissertation. Summing up, the literature appears to be not fully conclusive about the main determinants of economic growth, the existence of convergence and the impact of finance on growth.
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Praziquantel has been shown to be highly effective against all known species of Schistosoma infecting humans. Spherical nanoparticles made of poly(D,L-lactide-co-glycolide) acid with controlled size were designed as drug carriers. Praziquantel, a hydrophobic drug, was entrapped into the polymeric nanoparticles with 30% (w/w) of theoretical loading. The nanoparticles size was approximately of 350 nm with 66% of encapsulation efficiency. The everted gut sac model shows to be efficient to evaluate the drug permeation through the intestinal membrane. The results show that free praziquantel presents 4-fold times more permeation than praziquantel-loaded PLGA nanoparticles and physical mixture. For this drug, in special, this result can be interesting, since the nanoparticulate system can behave as a drug reservoir and/or to have a more localized effect in intestinal membrane for a prolonged period of time, since great amounts of parasites can be usually found in the mesenteric veins.
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Este trabalho consiste na proposta de utilização, em Odontologia, de uma abordagem metodológica usada em pesquisas qualitativas, denominada Grounded Theory, quando se objetiva compreender fenômenos ou se pretende descrevê-los de acordo com o ponto de vista do sujeito. Pesquisas em saúde, utilizando abordagens qualitativas, estão sendo, cada vez mais, empregadas entre pesquisadores e, na Odontologia, esta abordagem metodológica proposta torna-se fundamental, no sentido de propiciar a exploração de assuntos ainda pouco trabalhados nesta perspectiva metodológica, possibilitando que as pesquisas adquiriram contribuições originais e, assim, ampliando nosso conhecimento. São apresentadas as etapas a serem seguidas nesta abordagem, elucidando-as com alguns exemplos de parte de entrevistas realizadas numa pesquisa que teve como objetivos: compreender a experiência do idoso com a saúde bucal ao longo da vida e desenvolver e validar um modelo teórico representativo dessa experiência.