4 research outputs found

    Análise espacial da mortalidade neonatal no Vale do Paraíba, 1999 a 2001

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    OBJETIVO: Analisar os padrões de distribuição espacial da mortalidade neonatal. MÉTODOS: Estudo ecológico e exploratório, utilizando técnicas de análise espacial dos dados de mortalidade neonatal no Vale do Paraíba paulista, nos anos 1999-2001. A análise estatística espacial utilizou uma base de dados georreferenciados de 35 municípios e rotinas de estatística espacial. Os dados de mortalidade foram obtidos na Secretaria de Estado da Saúde de São Paulo. As variáveis estudadas foram os coeficientes de mortalidade neonatal precoce, tardia e total, e o Índice de Desenvolvimento Humano relativos ao ano de 2000. Para avaliação da dependência espacial foram utilizados os coeficientes de autocorrelação de Moran global e o Índice de Moran local e analisadas as correlações entre as variáveis. RESULTADOS: Foram registrados 111.574 nascidos vivos, com 1.149 óbitos no período neonatal precoce (10,29/1.000 nascidos vivos), 285 no neonatal tardio (2,55/1.000 nascidos vivos) totalizando 1.434 óbitos no período neonatal (12,85/1.000 nascidos vivos). Os coeficientes de Moran (global) mostraram significância estatística (pOBJECTIVE: To assess the spatial distribution of neonatal mortality. METHODS: An ecological and exploratory study using a spatial distribution of mortality data approach was carried out in the Paraiba Valley, Southeastern Brazil, from 1999-2001. Spatial analysis was conducted in a georeference database for 35 cities in the region and routines of spatial statistics. Mortality data were obtained from the State of São Paulo Health Department. The following variables were analyzed in this study: early, late and total neonatal mortality rates; and Human Development Index (HDI) values per city in 2000. Spatial dependency was measured using global Moran's Coefficients and local Moran's Index. A correlation analysis between variables was also conducted. RESULTS: There were 111,574 newborns with 1,149 deaths in the early neonatal period (10.29/1,000 newborns), 285 in the late neonatal period (2.5/1,000 newborns) totalizing 1,434 neonatal deaths (12.85/1,000 newborns). Estimated global Moran's coefficients showed statistical significance (

    Relationship between Scene Characteristics and Landsat Classification Performance of Corn and Soybeans

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    Accuracy of classification of Landsat MSS data depends on a number of parameters such as scene characteristics, training, classification, and area estimation procedures selected. The variability in accuracy that one may find using the same classification procedure applied at different locations is due primarily to scene variability. The understanding of the way that characteristics of a scene affect classifier performance is an important step to determine the amount of training, classification algorithm, and area estimation procedures that would be suitable to achieve an optimal accuracy. The objective of this paper was to sample a variety of corn and soybean areas in the U. S. Corn Belt and classify them using fixed training and classification procedures in order to determine how agronomic parameters of a scene affect the classification accuracy. The classifications were based on multitemporally registered Landsat MSS data acquired during the 1978 crop year over LACIE-type sample segments in several regions of the U.S. Corn Belt. Digital ground truth consisted of both wall-to-wall field observations of all ground covers present throughout the growing season and agronomic observations acquired simultaneously with Landsat passes, including percent ground cover, height and growth stage for several corn and soybean fields within each segment. Color IR aerial photographs were available for all segments. The classifications were performed using the per paint maximum likelihood classifier implemented in LARSYS, based on one visible and one near infrared channel from acquisitions at planting and after tasseling of corn. Segments selected for analysis bad similar Landsat data acquisition histories. A modified supervised training approach was used in a consistent fashion for a12 segments, Several characteristics of the scenes studied involving aspects of crops, soils and weather conditions were compared to classification performances. Analysis conducted in this investigation to date reveals that segment-to-segment variability has a significant effect on classification performance. Although high overall performances have been achieved for most of the segments, individual class performances have varied considerably from segment-to-segment. For example, accuracy for corn varied from 71 to 99 percent; for soybeans, it varied from 82 to 93 percent. Preliminary results have shown that units of the size of a segment are too large for comparisons with many of the important agronomic characteristics of a scene. Therefore, qualitative and quantitative comparisons between scene characteristics and classification performance of smaller units (1 nm square) are currently underway. In our presentation we will discuss several specific characteristics of the scenes involving particular aspects of crops, soils properties, and weather parameters that affect classification performances on a segment basis and within a segment based on smaller units
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