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Element enrichment factor calculation using grain-size distribution and functional data regression.
Sierra, C; Ordóñez, C; Saavedra, A; Gallego, J R.
Afiliação
  • Sierra C; Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador.
  • Ordóñez C; Department of Statistics, University of Vigo, 36310 Vigo, Spain. Electronic address: ordonezcelestino@uniovi.es.
  • Saavedra A; Campus de Mieres, Gonzalo Gutiérrez Quirós, s/n, 33600 Mieres, Asturias, Spain.
  • Gallego JR; Department of Statistics, University of Vigo, 36310 Vigo, Spain.
Chemosphere ; 119: 1192-1199, 2015 Jan.
Article em En | MEDLINE | ID: mdl-25460761
In environmental geochemistry studies it is common practice to normalize element concentrations in order to remove the effect of grain size. Linear regression with respect to a particular grain size or conservative element is a widely used method of normalization. In this paper, the utility of functional linear regression, in which the grain-size curve is the independent variable and the concentration of pollutant the dependent variable, is analyzed and applied to detrital sediment. After implementing functional linear regression and classical linear regression models to normalize and calculate enrichment factors, we concluded that the former regression technique has some advantages over the latter. First, functional linear regression directly considers the grain-size distribution of the samples as the explanatory variable. Second, as the regression coefficients are not constant values but functions depending on the grain size, it is easier to comprehend the relationship between grain size and pollutant concentration. Third, regularization can be introduced into the model in order to establish equilibrium between reliability of the data and smoothness of the solutions.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Poluentes do Solo / Modelos Lineares / Química / Interpretação Estatística de Dados / Ecologia / Poluição Ambiental / Modelos Teóricos Tipo de estudo: Prognostic_studies Aspecto: Determinantes_sociais_saude País/Região como assunto: Europa Idioma: En Revista: Chemosphere Ano de publicação: 2015 Tipo de documento: Article País de afiliação: Equador País de publicação: Reino Unido

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Poluentes do Solo / Modelos Lineares / Química / Interpretação Estatística de Dados / Ecologia / Poluição Ambiental / Modelos Teóricos Tipo de estudo: Prognostic_studies Aspecto: Determinantes_sociais_saude País/Região como assunto: Europa Idioma: En Revista: Chemosphere Ano de publicação: 2015 Tipo de documento: Article País de afiliação: Equador País de publicação: Reino Unido