924 resultados para REDSHIFT SURVEYS
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Includes bibliography
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Includes bibliography
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Incluye bibliografía.
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We examine the problem of combining Mexican inflation predictions or projections provided by a biweekly survey of professional forecasters. Consumer price inflation in Mexico is measured twice a month. We consider several combining methods and advocate the use of dimension reduction techniques whose performance is compared with different benchmark methods, including the simplest average prediction. Missing values in the database are imputed by two different databased methods. The results obtained are basically robust to the choice of the imputation method. A preliminary analysis of the data was based on its panel data structure and showed the potential usefulness of using dimension reduction techniques to combine the experts' predictions. The main findings are: the first monthly predictions are best combined by way of the first principal component of the predictions available; the best second monthly prediction is obtained by calculating the median prediction and is more accurate than the first one.
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In soil surveys, several sampling systems can be used to define the most representative sites for sample collection and description of soil profiles. In recent years, the conditioned Latin hypercube sampling system has gained prominence for soil surveys. In Brazil, most of the soil maps are at small scales and in paper format, which hinders their refinement. The objectives of this work include: (i) to compare two sampling systems by conditioned Latin hypercube to map soil classes and soil properties; (II) to retrieve information from a detailed scale soil map of a pilot watershed for its refinement, comparing two data mining tools, and validation of the new soil map; and (III) to create and validate a soil map of a much larger and similar area from the extrapolation of information extracted from the existing soil map. Two sampling systems were created by conditioned Latin hypercube and by the cost-constrained conditioned Latin hypercube. At each prospection place, soil classification and measurement of the A horizon thickness were performed. Maps were generated and validated for each sampling system, comparing the efficiency of these methods. The conditioned Latin hypercube captured greater variability of soils and properties than the cost-constrained conditioned Latin hypercube, despite the former provided greater difficulty in field work. The conditioned Latin hypercube can capture greater soil variability and the cost-constrained conditioned Latin hypercube presents great potential for use in soil surveys, especially in areas of difficult access. From an existing detailed scale soil map of a pilot watershed, topographical information for each soil class was extracted from a Digital Elevation Model and its derivatives, by two data mining tools. Maps were generated using each tool. The more accurate of these tools was used for extrapolation of soil information for a much larger and similar area and the generated map was validated. It was possible to retrieve the existing soil map information and apply it on a larger area containing similar soil forming factors, at much low financial cost. The KnowledgeMiner tool for data mining, and ArcSIE, used to create the soil map, presented better results and enabled the use of existing soil map to extract soil information and its application in similar larger areas at reduced costs, which is especially important in development countries with limited financial resources for such activities, such as Brazil.
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The Economic Commission for Latin America and the Caribbean (ECLAC) with support from the International Labour Organisation (ILO) and the Central Statistical Office in Saint Lucia convened a two-day Regional Workshop on Informal Sector Surveys for the Caribbean Subregion from 12 – 13 October 2009 in Castries, Saint Lucia. This workshop was one of the culminating activities of the United Nations Statistical Division-commissioned project Measurement of the Informal Sector and Informal Employment being conducted in the subregion since 2007. It was aimed primarily at disseminating the results of a 1-2 survey of the informal sector which was carried out in Saint Lucia over the period April 2008 to January 2009.
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The Economic Commission for Latin America and the Caribbean (ECLAC), Subregional Headquarters for the Caribbean, with support from the International Labour Organisation (ILO) and the Central Statistics Office in Saint Lucia, convened a two-day Data Dissemination Workshop on the Informal Sector and Informal Employment on 12 -13 October 2009 in Castries, Saint Lucia. This workshop was one of the culminating activities of the Interregional Project on the Measurement of the Informal Sector and Informal Employment being conducted in the Caribbean subregion. The workshop served as a forum for presenting the findings of the survey of the informal sector which was carried out in Saint Lucia over the period April 2008 to January 2009.
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Este artigo analisa a estrutura social dos entrevistados que apontam o item não resposta em um survey sobre assuntos políticos. Para isso foi realizado um survey com 2.110 jovens eleitores da rede pública de ensino em Belém (PA). Os dados indicam que a quota da não resposta aumenta com a mudança de um ciclo de vida para outro ou com a própria experiência obtida pelos efeitos das políticas públicas, o que deixa o entrevistado em dúvida em relação aos valores e opiniões estabelecidos.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)