908 resultados para Taxas de juros - Brasil - Modelos econométricos


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Este artigo busca analisar se empresas utilizam instrumentos de dvida corporativa para fazer gesto de risco tanto exposio taxa de juros quanto exposio cambial. Comparamos os coeficientes de regresses para avaliar a exposio a tais fatores de risco antes e depois da emisso da dvida corporativa. Utilizamos uma amostra de emisses de debntures de empresas brasileiras emitidas no Brasil e de bonds de empresas brasileiras emitidas em dlar. Os dados abrangem o perodo de janeiro de 2003 a dezembro de 2012. No encontramos evidncia do uso de instrumentos de emisso de dvida corporativa local e internacional como mecanismo de hedge taxa de juros e variao da taxa de cmbio. Encontramos evidncia de que o derivativo para hedge cambial utilizado pela maioria das empresas emissoras de bonds. Entretanto, no observamos o mesmo comportamento quando da exposio taxa de juros para emissoras de dvida corporativa local.

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Segundo Sampaio (2002), os modelos intertemporais de equilbrio comearam a ter a sua eficcia na determinao do retorno dos ativos questionada aps a publicao do artigo de Mehra e Prescott em 1985. Tendo como objeto de anlise os dados observados no mercado norte-americano, os autores no foram capazes de reproduzir a mdia histrica do prmio do retorno das aes em relao ao retorno dos ttulos pblicos de curto prazo atravs de parmetros comportamentais dentro de intervalos considerados plausveis. Atravs das evidncias, os autores, ento, puderam verificar a necessidade de coeficientes exageradamente altos de averso ao risco para equiparao do prmio de risco histrico mdio das aes norte-americanas, enigma que ficou conhecido como equity premium puzzle (EPP). Foi possvel tambm a constatao de outro paradoxo: a necessidade de taxas de desconto intertemporais negativas para obteno da mdia histrica da taxa de juros, o risk-free rate puzzle (RFP). Este trabalho tem como objetivo adaptar os dados do modelo proposto por Mehra e Prescott (2003) ao mercado brasileiro e notar se os puzzles apresentados anteriormente esto presentes. Testa-se o CCAPM com dados brasileiros entre 1995:1 e 2013:4 adotando preferncias do tipo utilidade esperada e atravs da hiptese de log-normalidade conjunta dos retornos. Utiliza-se o mtodo de calibrao para avaliar se h EPP no Brasil. Em linha com alguns trabalhos prvios da literatura nacional, como Cysne (2006) e Soriano (2002) que mostraram a existncia do puzzle nos perodos de 1992:1-2004:2 e 1980:1-1998:4, respectivamente, conclui-se que o modelo usado por Mehra e Prescott (2003) no capaz de gerar o prmio de risco observado na economia brasileira. Sampaio (2002), Bonomo e Domingues (2002) e Issler e Piqueira (2002), ao contrrio, no encontram evidncias da existncia de um EPP brasileiro.

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Este trabalho apresenta as principais aplicaes de tcnicas de gesto de riscos ao estudo de interrupes em cadeias de fornecimento, tendo como motivao o caso do fornecimento de energia eltrica, assunto de extrema relevncia para o Brasil. Neste sentido, o clculo do custo do dficit ou perda de produo dada uma falha no fornecimento de energia eltrica (parmetro utilizado em todo o planejamento do setor eltrico brasileiro), foi escolhido como fator relevante a ser analisado. As principais metodologias existentes para a apurao desse parmetro so apresentadas fazendo uma comparao com aquela atualmente em uso no Brasil. Adicionalmente, apresentamos uma proposta de implementao para as metodologias alternativas, utilizadas no exterior, e baseadas no conceito de VOLL (Value of Lost Load) - medida do valor da escassez de energia para empresas ou consumidores individuais e fundamental para o desenho de programas de gerenciamento de demanda.

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Este trabalho tem por objetivo a anlise emprica dos fatores macroeconmicos que determinaram os nveis de spread bancrio para pessoas fsicas e pessoas jurdicas no Brasil no perodo ps-adoo do Plano Real at dezembro de 2012. Para isso foi utilizado um modelo de auto regresso vetorial com variveis representativas de fatores macroeconmicos. O Trabalho expe ainda algumas caractersticas da indstria bancria no Brasil e as particularidades do mercado de crdito praticado para pessoas fsicas e pessoas jurdicas. Os resultados deste trabalho evidenciaram que: (i) a taxa bsica de juros foi o principal fator macroeconmico de influncia do spread praticado tanto para pessoas fsicas quanto para pessoas jurdicas; (ii) Enquanto um impacto no nvel de inflao ocasionou maior influncia no spread para pessoas fsicas, um impacto na volatilidade da taxa bsica de juros influenciou positivamente o spread para pessoas jurdicas.

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O objetivo deste trabalho ajudar o investidor que optou por investir seus recursos no mercado imobilirio a tomar sua deciso de investimento com base nas caractersticas endgenas facilmente identificveis no prospecto dos Fundos de Investimento Imobilirios (FIIs). Foram selecionadas aquelas consideradas importantes pela literatura e foram construdos alguns modelos para testar sua influncia na rentabilidade. Inicialmente, foi construdo um modelo completo, com todas as variveis, que apresentou resultados pouco relevantes, j que a maioria das variveis no apresentou significncia. Em seguida, um modelo reduzido foi montado com as variveis que mais contribuam para a rentabilidade, obtendo-se resultados relevantes. Atravs desse modelo, observou-se que FIIs que investem em desenvolvimento imobilirio, com foco no mercado residencial e com baixas taxas de administrao, geraram maiores rentabilidades ao investidor.

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This Master s Thesis aims to use the theoretical models of growth with restricted balance of payments, specifically Kaldor (1970) and Thirlwall (1979) models, to analyze the behavior and the pattern of specialization of Brazilian exports and imports in the last years. It is observed that, in some periods, the pattern of specialization has contributed in restricting long-term growth of the Brazilian economy. It has been hypothesized that overall this is due to lack of structural transformation policies. To achieve this goal, it analyzed the performance of Brazilian exports and imports disaggregating them according to their technological content. The basis for comparison was a group of countries to which Brazil is inserted in, the BRIC. In this regard, the work is a comparative analysis by using descriptive statistics. It is concluded that the low rate of GDP growth experienced by Brazil since the 1980s can be explained in part by the decoupling of the Brazilian National Innovation System (NIS) and the Brazilian productive structure. This would be reducing the income elasticity of exports and raising imports, causing a pattern of specialization intensive primary commodities and labor and low-skill labor

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Este trabalho tem como objetivo estudar os sistemas de Classificaes existentes para a garantia da gesto da qualidade no setor hoteleiro, tendo como foco principal a Matriz de Classificao para os Meios de Hospedagem da EMBRATUR e a ISO 9000, observando os benefcios que esses sistemas e/ou processos de gesto podero vir a proporcionar para o setor hoteleiro no que se refere qualidade de seus servios. Para a obteno dessas informaes foi realizada uma anlise comparativa dos sistemas de gesto da qualidade atravs de pesquisas bibliogrficas e de questionrios enviados para empreendimentos hoteleiros certificados e classificados, onde os principais resultados fornecidos pela pesquisa foram trabalhados de forma a apresentar, de maneira clara, a superioridade de um sistema em relao ao outro

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The telecommunications industry has experienced recent changes, due to increasing quest for access to digital services for data, video and multimedia, especially using the mobile phone networks. Recently in Brazil, mobile operators are upgrading their networks to third generations systems (3G) providing to users broadband services such as video conferencing, Internet, digital TV and more. These new networks that provides mobility and high data rates has allowed the development of new market concepts. Currently the market is focused on the expansion of WiMAX technology, which is gaining increasingly the market for mobile voice and data. In Brazil, the commercial interest for this technology appears to the first award of licenses in the 3.5 GHz band. In February 2003 ANATEL held the 003/2002/SPV-ANATEL bidding, where it offered blocks of frequencies in the range of 3.5 GHz. The enterprises who purchased blocks of frequency were: Embratel, Brazil Telecom (Vant), Grupo Sinos, Neovia and WKVE, each one with operations spread in some regions of Brazil. For this and other wireless communications systems are implemented effectively, many efforts have been invested in attempts to developing simulation methods for coverage prediction that is close to reality as much as possible so that they may become believers and indispensable tools to design wireless communications systems. In this work wasm developed a genetic algorithm (GA's) that is able to optimize the models for predicting propagation loss at applicable frequency range of 3.5 GHz, thus enabling an estimate of the signal closer to reality to avoid significant errors in planning and implementation a system of wireless communication

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In Brazil, despite the decline in infant mortality in recent decades it still has high rates going against recommended by WHO. Being the largest percentage of infant mortality rate composed of neonatal deaths. Objective: A study was conducted to analyze the spatial distribution of neonatal mortality and its correlation with the biological, socioeconomic and maternal and child health care in the Brazilian states in the period from 2006 to 2010. Method: The study made thematic maps and correlation (LISA) for verification of spatial dependence and multiple linear regression models. Results: Was found that there is no spatial autocorrelation for neonatal mortality in the Brazilian states (R = 0.002, p = 0.48). Most of variables were correlated (r> 0.3, p <0.05) with neonatal mortality, forming clusters in the North and Northeast, with the highest rates of teenage mothers, low household income per capita, lower prenatal appointments and beds of Neonatal Intensive Care Unit. The number of Neonatal UCI beds remained independent effect after regression analysis. Conclusion: The study concludes that regional inequalities in living conditions and especially the access to maternal and child health services contribute to the unequal distribution of neonatal mortality in Brazil

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The area studied forms a thin NNE-directed belt situated south of Recife town (Pernambuco state), northeastern Brazil. Geologically, it comprises the Pernambuco Basin (PB), which is limited by the Pernambuco Lineament to the north, the Maragogi high to the south and the Pernambuco Alagoas massif to the west, all of them with Precambrian age. This thesis reports the results obtained for the Cabo Magmatic Province (CMP), aiming the characterization of the geology, stratigraphy, geochronology, geochemistry and petrogenesis of the Cretaceous igneous rocks presented in the PB. The PB is composed of the Cabo Formation (rift phase) at the base (polymictic conglomerates, sandstones, shales), an intermediate unit, the Estiva Formation (marbles and argillites), and, at the top, the Algodoais Formation (monomictic conglomerates, sandstones, shales). The CMP is represented by trachytes, rhyolites, pyroclastics (ignimbrites), basalts / trachy-andesites, monzonites and alkali-feldspar granite, which occur as dykes, flows, sills, laccoliths and plugs. Field observations and well descriptions show that the majority of the magmatic rocks have intrusive contacts with the Cabo Formation, although some occurrences are also suggestive of synchronism between volcanism and siliciclastic sedimentation. 40Ar/39Ar and zircon fission tracks for the magmatic rocks indicate an average age of 102 r 1 Ma for the CMP. This age represents an expressive event in the province and is detected in all igneous dated materials. It is considered as a minimum age (Albian) for the magmatic episode and the peak of the rift phase in the PB. The 40Ar/39Ar dates are about 10-14 Ma younger than published palynologic ages for this basin. Geochemically, the CMP may be divided in two major groups; i) a transitional to alkaline suite, constituted by basalts to trachy-andesites (types with fine-grained textures and phenocrysts of sanidine and plagioclase), trachytes (porphyrytic texture, with phenocrysts of sanidine and plagioclase) and monzonites; ii) a alkaline suite, highly fractionated, acidic volcano-plutonic association, formed by four subtypes (pyroclastic flows ignimbrites, fine-to medium-grained rhyolites, a high level granite, and later rhyolites). These four types are distinguished essentially by field aspects and petrographic and textural features. Compatible versus incompatible trace element concentrations and geochemical modeling based on both major and trace elements suggest the evolution through low pressure fractional crystallization for trachytes and other acidic rocks, whereas basalts / trachy-andesites and monzonites evolved by partial melting from a mantle source. Sr and Nd isotopes reveal two distinct sources for the rocks of the CMP. Concerning the acidic ones, the high initial Sr ratios (ISr = 0.7064-1.2295) and the negative HNd (-0.43 to -3.67) indicate a crustal source with mesoproterozoic model ages (TDM from 0.92 to 1.04 Ga). On the other hand, the basic to intermediate rocks have low ISr (0.7031-0.7042) and positive HNd (+1.28 to +1.98), which requires the depleted mantle as the most probable source; their model ages are in the range 0.61-0.66 Ga. However, the light rare earth enrichment of these rocks and partial melting modeling point to an incompatible-enriched lherzolitic mantle with very low quantity of garnet (1-3%). This apparent difference between geochemical and Nd isotopes may be resolved by assuming that the metasomatizing agent did not obliterate the original isotopic characteristics of the magmas. A 2 to 5% partial melting of this mantle at approximately 14 kbar and 1269oC account very well the basalts and trachy-andesites studied. By using these pressure and temperatures estimates for the generation of the basaltic to trachy-andesitic magma, it is determined a lithospheric stretching (E) of 2.5. This E value is an appropriated estimate for the sub-crustal stretching (astenospheric or the base of the lithosphere?) region under the Pernambuco Basin, the crustal stretching probably being lower. The integration of all data obtained in this thesis permits to interpret the magmatic evolution of the PB as follows; 1st) the partial melting of a garnet-bearing lherzolite generates incompatible-enriched basaltic, trachy-andesitic and monzonitic magmas; 2nd) the underplating of these basaltic magmas at the base of the continental crust triggers the partial melting of this crust, and thus originating the acidic magmas; 3rd) concomitantly with the previous stage, trachytic magmas were produced by fractionation from a monzonitic to trachy-andesitic liquid; 4th) the emplacement of the several magmas in superficial (e.g. flows) or sub-superficial (e.g. dykes, sills, domes, laccoliths) depths was almost synchronically, at about 102 r 1 Ma, and usually crosscutting the sedimentary rocks of the Cabo Formation. The presence of garnet in the lherzolitic mantle does not agree with pressures of about 14 kbar for the generation of the basaltic magma, as calculated based on chemical parameters. This can be resolved by admitting the astenospheric uplifting under the rift, which would place deep and hot material (mantle plume?) at sub-crustal depths. The generation of the magmas and their subsequent emplacement would be coupled with the crustal rifting of the PB, the border (NNE-SSW directed) and transfer (NW-SE directed) faults serving as conduits for the magma emplacement. Based on the E parameter and the integration of 40Ar/39Ar and palynologic data it is interpreted a maximum duration of 10-14 Ma for the rift phase (Cabo Formation clastic sedimentation and basic to acidic magmatism) of the PB

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Incluye Bibliografa

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Coffee is one of the main products of Brazilian agriculture, the country is currently the largest producer and exporter. Knowing the growth pattern of a fruit can assist in the development of culture indicating for example, the times of increased fruit weight and its optimum harvest, essential to improve the management and quality of coffee. Some authors indicate that the growth curve of the coffee fruit has a double sigmoid shape. However, it consists of just a visual observation without exploring the use of regression models. The aims of this study were: i) determine if the growth pattern of the coffee fruit is really double sigmoidal; ii) to propose a new approach in weighted importance re-sampling to estimate the parameters of regression models and select the most suitable double sigmoidal model to describe the growth of coffee fruits; iii) to study the spatial distribution effect of the crop in the growth curve of coffee fruits. In the first article the aim was determine if the growth pattern of the coffee fruit is really double sigmoidal. The models double Gompertz and double Logistic showed significantly superior fit to models of simple sigmoid confirming that the standard of coffee fruits growth is really double sigmoidal. In the second article we propose to consider an approximation of the likelihood as the candidate distribution of the weighted importance resampling, aiming to facilitate the process of obtaining samples of marginal distributions of each parameter. This technique was effective since it provided parameters with practical interpretation and low computational effort, therefore, it can be used to estimate parameters of double sigmoidal growth curves. The nonlinear model double Logistic was the most appropriate to describe the growth curve of coffee fruits. In the third article aimed to verify the influence of different planting alignments and sun exposure faces in the fruits growth curve. A difference between the growth rates in the two stages of fruit development was identified, regardless the side. Although it has been proven differences in productivity and quality of coffee, there was no difference between the growth curves in the different planting alignments herein studied.

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A partir de coletas biolgicas mensais na Baa do Guajar e Ilha do Mosqueiro, foram obtidas amostragens de Macrobrachium amazonicum para estudos de reproduo, densidade, relaes morfomtricas e dinmica de populaes. Adicionalmente, dois outros desenhos amostrais foram utilizados para estudo da capturabilidade da espcie sobre influncia de dois tipos de iscas e trs tamanhos de armadilhas e de sua distribuio espacial em dois canais perenes do mesmo esturio. Os resultados apontam para diferena na captura de M. amazonicum quando se utiliza isca de farelo de babau, porm a diferena unicamente na abundncia sendo que a estrutura populacional no modificada. A espcie mais abundante no perodo seco, corroborando a idia de maior capturabilidade dos recursos pesqueiros. A ilha do Combu o local onde os espcimes so mais encontrados e ainda com maiores tamanhos. As fmeas so significativamente maiores e mais pesadas que os machos, denotando a diferenciao no metabolismo devido reproduo. A proporo de machos maior nas menores classes de comprimento, o que pode indicar um aumento na predao de machos de menores tamanhos devido ao seu comportamento mais agressivo que o das fmeas ou simplesmente por que os machos que atingem comprimentos maiores que as fmeas sejam mais intensamente predados pela pesca, havendo o recrutamento apenas dos machos menores. O tamanho de primeira maturao (comprimento da carapaa) para ambos os sexos resultou em 11,5mm (11,5 mm nos machos e 11,2mm nas fmeas). A reproduo em M. amazonicum do tipo contnua ou peridica com um aumento gradativo entre os meses de outubro a maro. Os locais mais abrigados, como regies mais internas de canais de mar ou furos (comuns no esturio amaznico) so locais preferencialmente procurados por fmeas maduras para a desova e crescimento dos juvenis. Os parmetros de crescimento da curva de von Bertalanffy obtidos, foram bastante similares entre os sexos, sendo L = 44,8mm e K = 0,35 para os machos e L = 46,5 e K = 0,31 para as fmeas. As taxas de mortalidade e explotao obtidas apontam para um estado limtrofe de explotao do recurso, neste sentido, o manejo dever ser tratado com bastante cuidado. A taxa atual de explotao encontra-se no seu limite mximo de sustentabilidade. Nesta situao, qualquer aumento do esforo poder ocasionar um estado de sobre-explotao de crescimento. Aliado ao estado de quase comprometimento dos estoques de M. amazonicum, a situao scio econmica dos pescadores tambm no diferente dos demais sistemas pesqueiros do litoral do Par: baixa escolaridade, atuao deficiente das entidades de classe, cadeia produtiva complexa e que desprivilegia os seus principais atores. Sugere-se o monitoramento estatstico da produo; a delimitao do tamanho mnimo de captura em 4,5cm de comprimeto total; a proibio da pesca com matapis em reas de cabeceira de furos e canais de mar; um censo de usurios e a utilizao de modelos bioeconmicos que contemplem os principais aspectos de sua cadeia biolgica e produtiva.