805 resultados para challenge hypothesis


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This paper the stastistical properties of the real exchange rates of G-5 countries for the Bretton-Woods peiod, and draw implications on the purchasing power parity (PPP) hypothesis. In contrast to most previous studies that consider only unit root and stationary process to describe the real exchange tae, this paper also considers two in-between processes, the locally persistent process ans the fractionally integrated process, to complement past studies. Seeking to be consistent with tha ample evidence of near unit in the real exchange rate movements very well. This finding implies that: 1) the real exchange movement is more persistent than the stationary case but less persistent than the unit root case; 2) the real exchange rate is non-stationary but the PPP reversion occurs and the PPP holds in the long run; 3) the real exchange rate does not exhibit the secular dependence of the fractional integration; 4) the real exchange rate evolves over time in a way that there is persistence over a range of time, but the effect of shocks will eventually disappear over time horizon longer than order O (nd), that is, at finite time horizon; 5) shocks dissipation is fasters than predicted by the fractional integracion, and the total sum of the effects of a unit innovation is finite, implying that a full PPP reversion occurs at finite horizons. These results may explain why pasrt empirical estudies could not provide a clear- conclusion on the real exchange rate processes and the PPP hypothesis.

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The aim of this paper is to test whether or not there was evidence of contagion across the various financial crises that assailed some countries in the 1990s. Data on sovereign debt bonds for Brazil, Mexico, Russia and Argentina were used to implement the test. The contagion hypothesis is tested using multivariate volatility models. If there is any evidence of structural break in volatility that can be linked to financial crises, the contagion hypothesis will be confirmed. Results suggest that there is evidence in favor of the contagion hypothesis.

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This paper investigates whether or not multivariate cointegrated process with structural change can describe the Brazilian term structure of interest rate data from 1995 to 2006. In this work the break point and the number of cointegrated vector are assumed to be known. The estimated model has four regimes. Only three of them are statistically different. The first starts at the beginning of the sample and goes until September of 1997. The second starts at October of 1997 until December of 1998. The third starts at January of 1999 and goes until the end of the sample. It is used monthly data. Models that allows for some similarities across the regimes are also estimated and tested. The models are estimated using the Generalized Reduced-Rank Regressions developed by Hansen (2003). All imposed restrictions can be tested using likelihood ratio test with standard asymptotic 1 qui-squared distribution. The results of the paper show evidence in favor of the long run implications of the expectation hypothesis for Brazil.

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O presente trabalho tem o objetivo de identificar e estudar os principais entraves técnicos, administrativos e burocráticos que desafiam a solidificação da Zona Franca de Manaus como Pólo Industrial Exportador. O levantamento da bibliografia técnica, legislação federal e a pesquisa de campo realizada constituem-se na sustentação do estudo. A hipótese de que existem entraves administrativos, técnicos e burocráticos que se estabelecem como os principais desafios que dificultam a consolidação do Distrito Industrial instalado na Zona Franca de Manaus permite buscar o mapeamento desses desafios a serem enfrentados pelos atuais e potenciais exportadores.

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On March 4, 1999, the newly appointed President of the Brazilian Central Bank, Mr Armínio Fraga, raised interest rates to a staggering 45% per annum. The objective of that decision was to keep foreign investors assets in Brazil, and prevent the country from default. At the time, Brazil suffered frem an enormously intense crisis of confidence, and fears of such default were widespread. Mr Fraga was walking a very fine line when making that decision, for it could bring forth unintended effects: the market, already concerned about Brazil's sustainability, could perceive the increased rate as an irreversible step towards the abyss inevitable default. Economic theory postulates the rational actor model as the driving force behind economic decision-making. The objective of this thesis is to present and discuss the hypothesis that this particular decision, and by extension many others, are better explained threugh the recognition-primed decision mode!.

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Este trabalho consiste em estudar modelos incluindo agentes com informação completa e incompleta sobre o ambiente econômico. Prova-se a existência de equilíbrio em que esses dois agentes coexistem e sob, algumas condições, obtêm-se que esse equilíbrio é recursivo e contínuo, ou seja, pode ser implementado por uma função contínua de transição que relaciona as variáveis de equilíbrio entre dois períodos consecutivos. Mostra-se, sob algumas hipóteses, que em equilíbrios recursivos contínuos, os agentes que cometem erros persistentes nas antecipações dos preços de equilíbrio são eliminados do mercado. Finalmente, exibimos diversos exemplos numéricos, no caso de mercados incompletos e informação completa, em que os agentes com expectativas racionais são eliminados do mercado. Usam-se métodos numéricos alternativos que possibilitam computar um equilíbrio em modelos com agentes heterogêneos.

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A doença holandesa tornou-se amplamente conhecida na década de 1960, quando a descoberta repentina de reservatórios de gás natural em território holandês, na região do mar do norte, transformou o país em uma economia rica em recursos. A desagradável consequência que proveio da recém-adquirida abundância de commodities foi o declínio da próspera indústria holandesa, que perdeu sua competitividade devido à valorização do florim holandês, como consequência do aumento do influxo de capital estrangeiro no país. Desde então este fenômeno tem sido observado em diversos países que possuem abundância de commodities. O objetivo desta tese é aplicar o modelo da doença holandesa ao Brasil, já que a maior economia da América latina poderá também ter de encarar a ameaça de se tornar prisioneira da “armadilha das commodities”, devido à sua abundância de recursos naturais. O autor revisa a bibliografia básica abordando o tema geral da doença holandesa e dá enfoque a estudos realizados anteriormente no Brasil. Além disso, os quatro maiores sintomas que caracterizam a doença holandesa são testados: (1) valorização das taxas de câmbio do real, (2) declínio do setor industrial, (3) crescimento do setor de serviços, e (4) aumento dos salários. Todos estes sintomas foram observados e podem ser comprovados através das abordagens de cointegração ou de correlação, com exceção do sintoma número dois. Ainda que estes resultados sejam significativos, há muito outros fatores determinantes que influenciam o desenvolvimento dos sintomas examinados, motivo pelo qual futuros estudos serão necessários para se obtiver conclusões definitivas sobre como o Brasil é afetado pela doença holandesa.

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O Procedimento de Manifestação de Interesse (“PMI”) vem sendo utilizado por diferentes entes federativos brasileiros, principalmente nos últimos dois anos, quando o instituto foi regulamentado em muitos Estados. Seu objetivo é viabilizar a modelagem de projetos de infraestrutura sem onerar os cofres públicos e sem requerer expertise técnica pública. Insere-se no contexto de incentivo às possíveis sinergias oriundas das parcerias entre os setores público e privado. Entretanto, é importante considerar como principal obstáculo para a utilização do PMI a possibilidade de discrepância entre o interesse público e o privado. A análise econômica do direito oferece ferramentas capazes de contribuir com a averiguação dessa possível discrepância, tal como a teoria da agência. As premissas teóricas da agência podem ser aplicada à autorização conferida pelo poder público ao particular. No que tange ao conteúdo, o interesse visado pelo mercado com a elaboração de estudos de viabilidade pode destoar da persecução pelo interesse público, norte da Administração Pública. Em nível procedimental, é possível que ocorra a captura do interesse público na realização de um procedimento licitatório – capaz de selecionar o parceiro privado mais apto a cumprir com o objeto contratual – pelo particular autorizado a elaborar os estudos de viabilidade. Para tanto, foi realizado levantamento empírico acerca dos projetos de infraestrutura modelados via PMI, em que já ocorreu a licitação para contratos de PPPs, a fim de confirmar a hipótese de captura.

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Allergic asthma represents an important public health issue, most common in the paediatric population, characterized by airway inflammation that may lead to changes in volatiles secreted via the lungs. Thus, exhaled breath has potential to be a matrix with relevant metabolomic information to characterize this disease. Progress in biochemistry, health sciences and related areas depends on instrumental advances, and a high throughput and sensitive equipment such as comprehensive two-dimensional gas chromatography–time of flight mass spectrometry (GC × GC–ToFMS) was considered. GC × GC–ToFMS application in the analysis of the exhaled breath of 32 children with allergic asthma, from which 10 had also allergic rhinitis, and 27 control children allowed the identification of several hundreds of compounds belonging to different chemical families. Multivariate analysis, using Partial Least Squares-Discriminant Analysis in tandem with Monte Carlo Cross Validation was performed to assess the predictive power and to help the interpretation of recovered compounds possibly linked to oxidative stress, inflammation processes or other cellular processes that may characterize asthma. The results suggest that the model is robust, considering the high classification rate, sensitivity, and specificity. A pattern of six compounds belonging to the alkanes characterized the asthmatic population: nonane, 2,2,4,6,6-pentamethylheptane, decane, 3,6-dimethyldecane, dodecane, and tetradecane. To explore future clinical applications, and considering the future role of molecular-based methodologies, a compound set was established to rapid access of information from exhaled breath, reducing the time of data processing, and thus, becoming more expedite method for the clinical purposes.

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Pacus Piaractus mesopotamicus alimentados com dietas contendo três níveis de vitaminas C e E (zero, 250 e 500mg/kg de ração) foram desafiados, em diferentes temperaturas, com Aeromonas hydrophila. Os peixes foram mantidos em caixas plásticas de 300L e, com o objetivo de reduzir as reservas vitamínicas, durante os primeiros 60 dias, foram alimentados com dietas isentas das vitaminas C e E. Após esse período, os peixes foram estocados na densidade inicial de 14 peixes/caixa e as dietas-teste foram oferecidas durante 60 dias. Ao final do experimento, todos os peixes foram infectados com 6×10(6) UFC de A. hydrophila/peixe, injetada intraperitonealmente. Não houve interação nível de vitamina C vs. nível de vitamina E quanto à mortalidade. A suplementação com as vitaminas C e E não reduziu a taxa de mortalidade dos peixes desafiados com A. hydrophila. Independentemente da suplementação vitamínica, após o desafio, os peixes menores apresentaram maior taxa de mortalidade que os maiores e o grupo mantido em ambiente com temperatura mais alta apresentou maior taxa de mortalidade após o desafio.

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In contemporary society, social exclusion is an actual and pertinent theme, because it presents itself as a challenge to management and planning of the public policies. In this perspective, the thesis entitled "The Cultural Corridor: space materialization of social exclusion in Mossoró-RN" is a moment of apprehension and analysis of the local reality from the urban policy implementation that emphasized an enterprising model, which has, as the concrete space to urban renovation manifestation, the cultural complex called cultural corridor. Because of the investigation and the directional hypothesis, it is possible to say that the urban development policy implemented in Mossoró, starting from the 1990 decade, based in the model of modernizing/enterprising management, has been causing an intensification of a society parcel exclusion from the city public space, since this public policy didn't prioritized job market increasing, as well as population incomes improving, poverty and social inequality reduction, at the same proportions it promoted geographic space reorganization with directional actions to build the "spectacle city"

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The present work consists of studying to diffuse control of constitutionality in Brazil, with emphasis in a procedural alternative to the evolution of that model: the incident to challenge of unconstitutionality. Starting from the discussion about the new role of constitutional jurisdiction in peripheral countries and in the globalized society, without forgetting to face inevitable doubts about its legitimacy before other powers of the State, the Brazilian control of constitutionality is revealed, under a diffuse, non-dichotomical view, through a number of inconsistencies and misunderstandings, that compromise social peace, the credibility of democratic institutions and the supremacy of juridical security. In order to achieve the goal, the study in course discussed the main difficulties of the Brazilian mixed model of constitutionality control, as well as, directing its view to the incident of challenge of unconstitutionality, which the most adequate forms to assure its appropriateness, legitimacy, processing and decisory effects are. Is was essential, in this point of view, to establish the difference between the incident of challenge of unconstitutionality conceived in article of the Brazilian Federal Constitution and the incident of challenge of unconstitutionality such as it is known in the European models. The insertion of the incident of challenge of unconstitutionality based on European models in the Brazilian control system, without jeopardizing the North-American essence the Brazilian constitutional history presents since 1981, is the hypothesis that is presented as an improvement of constitutional protection

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The inherent complexity of natural communities is a challenge to our understanding about how the habitat influences the abundance, local distribution and species diversity. The habitat can influence community structure in multiple ways and elucidate these relationships has provoked a lot of debate in ecology. The habitat heterogeneity hypothesis states that an increase in habitat heterogeneity (number of habitats) leads to an increase in species diversity in the landscape due to an expansion in niche dimensions. This study aims to identify whether this hypothesis is valid for the spiders that inhabit a locality in the Caatinga of northeastern Brazil. Cursorial and arboreal spiders were sampled in 30 plots within an area of Caatinga together with measures of environmental complexity, habitat heterogeneity and environmental parameters related to multiple aspects of vegetation architecture and species composition of woody plants. Stepwise multiple regressions were used to define which local environmental parameters best explain the variation in arboreal and cursorial spiders richness. Then a NMDS (Nonmetric multidimensional scaling) was used to reduce the number of predictive variables to those who are the most important and best represent the variation in spiders richness associated with the environment they were sampled. The results show a clear segregation between the guilds of arboreal and cursorial spiders, both related to what kind of environmental variables best explain its variation as well as in relation to what part of the vegetation they occupy

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The market-assisted land reform (RAAM) has been constituted as an alternative of agrarian reform funded by the Programa Nacional do Crédito Fundiário (PNCF). It is a policy of acquisition, distribution and use of Earth ideologically disseminated and funded by the World Bank in the context of productive insertion of landless workers. Accordingly, this study seeks to analyze the trajectory of rural settlements financed by this policy, seeking to understand what factors promote or limit the process of rural development of those settlements. To do so, take as a reference case study of the Assentamento da Fazenda Paz, in the municipality of Maxaranguape in the State of Rio Grande do Norte. From the methodological point of view, bibliographical and documentary research were used, in addition to visits to the settlement and semi-structured interviews with the settlers, trade union leaders, consultants and technicians linked to the project. Assuming the reports of respondents, initially constructs the hypothesis that informal and formal institutions present in the Assentamento da Fazenda Paz were unable to effectively coordinate the actions of the agents. The results obtained showed the existence of a very complex undertaking, with a total area of 607 hectares and 80 families settled, endowed with good quality water and irrigation infrastructure, with assets of approximately R$ 5 million reais. Experience experienced by the settlers understood the development of complex systems of production and marketing of fruits and vegetables, with an emphasis on the cultivation of papaya in an area of 45 hectares based on modern irrigation system and extensive use of technology. Collective management of production, marketing, revenue and costs stood out as a major challenge for the settlers and their representative organisations, i.e. the Community Association and the cooperative. From this observation it was possible to identify two moments on the trajectory of the project: the first, between 2007-2011, considered by respondents as successful, in which the integration of public policies and abundant input of revenue from the commercialization of the fruits da Paz, mainly through the sale of papaya and pineapple in national and international markets, allowed an average remuneration of R$ 800.00 reais to R$ 1,000 reais seated/monthIn addition to the production of vegetables and other types of products for sale and consumption; the second, from 2012, characterized as a failure, due to the discontinuity of the cultivation, production and marketing of fruits based on the collective bargaining model deployed. Important factors explain the discontinuity of the project, including the model of agriculture implemented, difficulties related to the management of production, marketing and finance the venture, in addition to the breach of trust between the Board of the cooperative and the associates and the distancing of the governmental organizations more directly responsible for the project. It is therefore concluded that we must to rethink rural development as a multidimensional phenomenon, requiring a broad engagement between State and society under the foundations of a territorial development contract