984 resultados para Earthquake magnitude


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The predominant knowledge-based approach to automated model construction, compositional modelling, employs a set of models of particular functional components. Its inference mechanism takes a scenario describing the constituent interacting components of a system and translates it into a useful mathematical model. This paper presents a novel compositional modelling approach aimed at building model repositories. It furthers the field in two respects. Firstly, it expands the application domain of compositional modelling to systems that can not be easily described in terms of interacting functional components, such as ecological systems. Secondly, it enables the incorporation of user preferences into the model selection process. These features are achieved by casting the compositional modelling problem as an activity-based dynamic preference constraint satisfaction problem, where the dynamic constraints describe the restrictions imposed over the composition of partial models and the preferences correspond to those of the user of the automated modeller. In addition, the preference levels are represented through the use of symbolic values that differ in orders of magnitude.

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Apresentamos a análise de diagramas cor-magnitude (CMDs) profundos para 5 aglomerados ricos da Grande Nuvem de Magalhães (LMC). Os dados fazem parte do projeto HST G07307, entitulado "Formação e Evolução de Aglomerados Estelares Ricos da LMC", e foram obtidos através do HST/WFPC2 nos filtros F555W (~ V) e F814W (~ I), alcançando V555~25. A amostra de aglomerados é composta por NGC 1805 e NGC 1818, os mais jovens (r < 100 Myr), NGC 1831e NGC 1868,de idades intermediárias (400 < r < 1000Myr), e Hodge 14, o mais velho (r > 1200Myr). Discutimos e apresentamos um método de correção dos CMDs para incompleteza da amostra e contaminação por estrelas de campo. O uso eficiente das informações contidas nos CMDs foi feito por meio de comparações entre os CMDs observados e CMDs modelados. O processo de modelamento de CMDs gera uma Seqüência Principal (MS) sintética, que utiliza como entrada do modelo a informação sobre idade (r), metalicidade (Z), Função de Massa do Presente (PDMF), fração de binárias não resolvidas, distância e extinção da luz. As incertezas fotométricas foram empiricamente determinadas a partir dos dados e incorporadas no modelamento. Técnicas estatísticas de comparação entre CMDs em 1D e 2D são apresentadas e aplicadas como métodos objetivos capazes de determinar a compatibilidade entre modelo e observação. Modelando os CMDs da região central dos aglomerados podemos inferir a metalicidade (Z), o módulo de distância intrínseco ((V - Mv)o) e o avermelhamento (E(B-V)) para cada aglomerado. Também determinamos as idades para os 3 aglomerados mais velhos de nossa amostra. Continuação) Através da comparação em 2D os valores encontrados foram os seguintes: para NGC 1805, Z = 0.007:1+-0.003, (V - Mv)o = 18.50:1+- 0.10, E(B - V) = 0.03:1+-0.01; para NGC 1818,Z = 0.005:1+-0.002, (V - Mv)o = 18.50:1+-0.15, E(B - V)~0.00; para NGC 1831, Z = 0.012:1+-0.002, log(r /yr) = 8.70 :I+-0.05, (V - Mv)o = 18.70:1+- 0.05, E(B - V)~ 0.00; para NGC 1868, Z = 0.008:1+-0.002,log(r/yr) =8.95:1+-0.05, (V - Mv)o = 18.70:1+- 0.05, E(B - V) ~0.00; para Hodge 14, Z = 0.008+-0.004, log(r/yr) = 9.23+-0.10, (V - Mv)o = 18.50+-0.15, E(B - V) = 0.02+- 0.02. Estes valores estão de acordo, dentro das incertezas, com os valores obtidos através da análise de linhas fiduciais (lD), o que agrega confiabilidade a estas determinações. Através da análise de CMDs em regiões concêntricas determinamos a dependência espacial da inclinação da PDMF (a) nos aglomerados mais ricos. Para tanto empregamos duas abordagens distintas para a determinação de a: 1) método tradicional em 1D via conversão direta de V555em massa; 2) método em 2D via modelmento de CMDs. Independente do método de análise, todos os aglomerados analisados demonstram claramente o efeito de segregação em massa. Além disso, NGC 1818, NGC 1831 e NGC 1868 apresentam uma possível perda seletiva de estrelas de baixa massa nas suas regiões mais externas.

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Contexto: O diabetes mellitus (DM) é uma causa importante de morbimortalidade nas sociedades ocidentais devido à carga de sofrimento, incapacidade, perda de produtividade e morte prematura que provoca. No Brasil, seu impacto econômico é desconhecido. Objetivos: Dimensionar a participação do DM nas hospitalizações da rede pública brasileira (1999-2001), colaborando na avaliação dos custos diretos. Especificamente, analisar as hospitalizações (327.800) e os óbitos hospitalares (17.760) por DM como diagnóstico principal (CID-10 E10-E14 e procedimento realizado) e estimar as hospitalizações atribuíveis ao DM, incluindo as anteriores e aquelas por complicações crônicas (CC) e condições médicas gerais (CMG). Métodos: A partir de dados do Sistema de Informação Hospitalar do Sistema Único de Saúde (SIH/SUS) (37 milhões de hospitalizações), foram calculados indicadores por região de residência do paciente e sexo (ajustados por idade pelo método direto, com intervalos de confiança de 95%), faixas etárias, médias de permanência e de gastos por internação e populacional em US$. Realizou-se regressão logística múltipla para o desfecho óbito. As prevalências de DM foram combinadas aos riscos relativos de hospitalização por CC e CMG (metodologia do risco atribuível) e somadas às internações por DM como diagnóstico principal. Utilizou-se análise de sensibilidade para diferentes prevalências e riscos relativos. Resultados: Os coeficientes de hospitalizações e de óbitos hospitalares e a letalidade por DM como diagnóstico principal atingiram respectivamente 6,4/104hab., 34,9/106hab. e 5,4%. As mulheres apresentaram os coeficientes mais elevados, porém os homens predominaram na letalidade em todas as regiões. O gasto médio (US$ 150,59) diferiu significativamente entre as internações com e sem óbito, mas a média de permanência (6,4 dias) foi semelhante. O gasto populacional equivaleu a US$ 969,09/104hab. As razões de chances de óbito foram maiores para homens, pacientes ≥75 anos, e habitantes das regiões Nordeste e Sudeste. As hospitalizações atribuíveis ao DM foram estimadas em 836,3 mil/ano (49,3/104hab.), atingindo US$ 243,9 milhões/ano (US$ 14,4 mil/104hab.). DM como diagnóstico principal (13,1%), CC (41,5%) e CMG (45,4%) responderam por 6,7%, 51,4% e 41,9% respectivamente dos gastos. O valor médio das internações atribuíveis (US$ 292) situou-se 36% acima das não-atribuíveis. As doenças vasculares periféricas apresentaram a maior diferença no valor médio entre hospitalizações atribuíveis e não-atribuíveis (24%), porém as cardiovasculares destacaram-se em quantidade (27%) e envolveram os maiores gastos (37%). Os homens internaram menos (48%) que as mulheres, porém com gasto total maior (53%). As internações de pacientes entre 45-64 anos constituíram o maior grupo (45%) e gastos (48%) enquanto os pacientes com ≥75, os maiores coeficientes de hospitalização (350/104hab.) e de despesa (US$ 93,4 mil/104hab.). As regiões mais desenvolvidas gastaram o dobro (/104hab.) em relação às demais. Considerações Finais e Recomendações: As configurações no consumo de serviços hospitalares foram semelhantes às de países mais desenvolvidos, com importantes desigualdades regionais e de sexo. O gasto governamental exclusivamente com hospitalizações atribuíveis ao DM foi expressivo (2,2% do orçamento do Ministério da Saúde). A ampliação de atividades preventivas poderia diminuir a incidência do DM, reduzir a necessidade de internações, minimizar as complicações e minorar a severidade de outras condições médicas mais gerais.

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In this paper we investigate how several national educational policies and practices influence both students' average reading achievement and the social distributioll of achievement within schools and countries. Data come fJ:om the 2000/2001 administration of PISA (programme for International Student Assessment) by the Organization for Economic Cooperation and Developrnent (OECD). They include observations from 212,880 lS-year-old students attending 8,038 secondary schools, which are located in 39 countries. We analyze these data with three-level Hierarchical Linear Models (HLM), with students nested in schools, which are nested within countries. Results focus on the role played by three country-level educational policies: (1) retention/repetition; (2) the mix of students in schools based on socioeconomic status (school social mix); and vocational education. We explore how these policies influence the social distribution of achievemer.t between schools within countries. Implications of these findings are discussed.

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Studies on the effects of changes in biodiversity and ecosystem functioning have been a central theme in ecology over the past two decades. Several studies have showed that the diversity of plant debris differently affects the decomposition process in aquatic and terrestrial environments, but we know very about the effects of detritus diversity on decomposition under fluctuating environmental conditions. We tested whether and how the environmental contexts, as well as the dynamic of their alternation, influence the effects of detritus diversity on the decomposition process. We performed a field experiment where we manipulate the litter diversity of 8 species of terrestrial plants decomposing (litterbags) in single and in mixture containing the eight species together in three different environmental contexts: the terrestrial environment (T), aquatic (A) and interface (I) - experimental treatment that simulates variation in flooding regime. We measured the rate of decomposition through the loss of mass of the community and each individual detritus in monocultures and mixtures. Species richness and environmental variability had no effects on the magnitude and stability of the decomposition process. However, there were significant diversity effects on the decomposition of an individual alien species, F. benjamina. Environmental context had significant effects on the magnitude and variability of decomposition. Detritus decomposition was faster and more variable on aquatic, interface and terrestrial conditions, respectively. Our results demonstrate that the diversity of plant detritus has minor effects to the decomposition across disparate environmental conditions and suggest that it is necessary to consider the potential of other abiotic factors in affect the magnitude and variability of the decomposition processes

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The work is to make a brief discussion of methods to estimate the parameters of the Generalized Pareto distribution (GPD). Being addressed the following techniques: Moments (moments), Maximum Likelihood (MLE), Biased Probability Weighted Moments (PWMB), Unbiased Probability Weighted Moments (PWMU), Mean Power Density Divergence (MDPD), Median (MED), Pickands (PICKANDS), Maximum Penalized Likelihood (MPLE), Maximum Goodness-of-fit (MGF) and the Maximum Entropy (POME) technique, the focus of this manuscript. By way of illustration adjustments were made for the Generalized Pareto distribution, for a sequence of earthquakes intraplacas which occurred in the city of João Câmara in the northeastern region of Brazil, which was monitored continuously for two years (1987 and 1988). It was found that the MLE and POME were the most efficient methods, giving them basically mean squared errors. Based on the threshold of 1.5 degrees was estimated the seismic risk for the city, and estimated the level of return to earthquakes of intensity 1.5°, 2.0°, 2.5°, 3.0° and the most intense earthquake never registered in the city, which occurred in November 1986 with magnitude of about 5.2º

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this dissertation we studied the seismic activity in the São Caetano county, Pernambuco State, Northeastern Brazil, located near the Pernambuco Lineament. The Pernambuco Lineament is a one of Neoproterozoic continental-scale shear zones that deforms the Borborema province. The seismicity estudied occurred in a NE trending branch of Pernambuco Lineament. The seismic activity in São Caetano started in 2006 and in May 20th, 2006 a 4,0 mb earthquake hit there. This was the largest earthquake ever reported in Pernambuco State. This dissertation is the result of a campaign done in the period from Februay 1th 2007 to July 31 th 2007. In this campaign up to nine three-component digital seismographic stations were deployed and the collected data was used to determine hypocenters and focal mechanism. A total of 214 earthquakes, recorded at least by three stations, were analyzed. To determine hypocenters and time origin the HYPO71 program was used assuming a half-space model with parameters : VP (P-wave velocity) equal to 5.90 km/s and the ratio VP/VS 1.70, where VS is the S-wave velocity. The earthquakes hypocentral distribution was approximately 4 km long and agrees with the NE-SW direction of the Pernambuco Lineamento branch. Hypocentres depth range from 2 to 8 km. The composed focal mechanism was made from a group of 14 selected earthquakes. We try firstly to find the fault plane solution matching the polarity distribution at stations, using the FPFIT program. The result was 43 deg ± 15 deg for strike, 59 deg ± 9 deg for dip and -142 deg ± 15 deg for rake. We also fitted a plane using the hypocentral distribution to obtain the dip and azimuth of the hypocentral distribution. The results obtained by this fit were 58 deg for the azimuth, 55 deg for the dip and -155 deg for rake. This result shows a mechanism of a strike-slip dextral fault with a normal component. This dissertation shows, once more, that there is a good correlation between the seismic activity and geological features in the region near the Pernambuco Lineament and its NE branches

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In this dissertation it was studied the rupture characteristic of earthquakes of the Town of Cascavel CE, Northeastern Brazil. Located on the border of the Potiguar Basin, the Town of Cascavel is one of the most seismically active intraplate areas in the country. In this town, on November 20th, 1980 a 5,2mb earthquake occurred. This was the largest earthquake ever reported in Northeast Brazil. Studies of this region using instruments were possible after 1989, with several campaigns being done using seismographic networks. From the beginning of the monitoring to April 2008 more than 55,000 events were recorded. With the data collected by a network with six 3-components digital seismographic stations during the campaigns done from September 29th, 1997 to March 5th, 1998, estimates of source parameters were found fitting the displacement spectra in the frequency domain for each event. From the fitting of the displacement spectra it was possible to obtain the corner frequency ( ) c f and long period amplitude ( ) W0 . Source parameters were determined following Brune (1970) and Madariaga (1976) models. Twenty-one seismic events were analyzed (0.7 £ £ 2.1) b m in order to estimate the source dimension (r ), seismic moment ( ) M0 , static stress drop (Ds ), apparent stress ( ) a s , seismic energy ( ) S E and moment magnitude ( ) W M for each of the events. It was observed that the ratio between radiated seismic energy and moment seismic (apparent stress) increases with increasing moment and hence magnitude at the observed range. As suggested by Abercrombie (1995), also in this work there is a breakdown in the scaling for earthquakes with magnitudes smaller than three ( < 3.0) W M , so that the rupture physics is different for larger events. If this assumption is valid, the earthquakes analyzed in this work are not selfsimilar. Thus, larger events tend to radiated more energy per unit area than smaller ones.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Includes bibliography

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Includes bibliography

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Includes bibliography