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Beginning with the classical Gauss-Markov Linear Model for mixed effects and using the technique of the Lagrange multipliers to obtain an alternative method for the estimation of linear predictors. A structural method is also discussed in order to obtain the variance and covariance matrixes and their inverses.
Através do modelo linear clássico de Gausss-Markov caracterizado como modelo de efeitos mistos, aplicou-se a tecnologia dos multiplicadores de Lagrange para obter um método alternativo de estimação de preditores lineares. Além disso, é proposto um critério estrutural simples para a obtenção das matrizes de variâncias, covariâncias e de suas inversas

Comparison of organic carbon from humic and fulvic acids and the degree of humification in five soil ordersComparación del carbono orgánico proveniente de los ácidos húmicos, ácidos fúlvicos y el grado de humificación en cinco órdenes de suelos

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Además de que la Química de Productos Naturales es muy adecuada para hacer extensiva investigación básica, también es indudable que genera moléculas además de información estructural y biológica, para solucionar diversos problemas humanos, especialmente en el campo farmacológico, la agricultura, los cosméticos, los alimentos y otras aplicaciones industriales...

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Humic substances (HS) are the main component of soil organic matter (SOM), a product of the pedogenetic process. In this study, the morphometric factors and climatic variable that condition the degree of humification, the organic carbon content of humic acids (HA) fulvic acids (FA) of 42 soil samples are related through the functional equation of factors of state of the soil proposed by Jenny. The degree of humification was determined by the Nagoya method proposed by Kumada. The quantification of organic carbon was determined using the method by Walkley and Black. The morphometric parameters of the relief were obtained from the Digital Elevation Model (DEM) and the climate parameter of the MODIS sensor. The results show that the relief factor conditions the degree of humification and the climate factor conditions the organic carbon content of humic acids (HA) and fulvic acids (FA).