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Theoretical-practical and analytical aspects of the Mathematical-Statistical Modeling related to the Response Surface Methodology (MSR) are outlined. The themes of these contributions are on the Mathematical-Statistical Modeling, the Experimental Design and the applications in the agrarian field of Cuba and other countries, as well as the software used for this analysis. In the scientific and teaching literature of Cuba and other countries, in general there are not many studies and researches that support applications of the MSR and the possibilities that this tool offers in determining the optimal conditions of the levels of the factors that affect in the response of certain processes under investigation, including a smaller number of treatments. Therefore it is a powerful tool of Mathematics and Statistics in the scientific-research development of different processes of agricultural sciences and other branches. To contribute to the achievement of greater dissemination and application of this type of modeling, the objective of this review is to disseminate theoretical and practical aspects related to MSR and its applications in agricultural sciences and other related fields. [ABSTRACT FROM AUTHOR] more...

This work is about the Multicollinearity problem between the regressive variables in a Multiple Lineal Regression Model. There are many ambiences in the Agro sciences in which this problem can be found. So, in this work and to create, in the data which is really necessary for this study, a multicollinearity situation, explicative variables were generated in a way that at least two of them had a certain degree of dependency, that is to say "an almost lineal combination. Once these conditions are created, an analysis of the Multicollinearity is established taking into consideration the symptom, the diagnose and the treatment. For the symptom, the correlation between regressive variable pairs, the F partial and total test on regressive coefficients, the standard error in each estimator and the determination of the coefficient, among others, were deeply analyzed. For the diagnose, a diagonalization of the correlation matrix was used as well the study of the last own values that gives us a precise information. For the treatment, the Ridge Regression and the Regression of Principal Components were used which resulted very efficient to accurately describe the estimators in the Multiple Lineal Regression Model. [ABSTRACT FROM AUTHOR] more...

Los problemas con que cuenta actualmente el departamento de La Guajira y en especial el Municipio de Riohacha en los aspectos social, económica y empresarial, hacen necesario el diseño e implementación de una acción inmediata, coherente y ambiciosa que le permitan su recuperación en una senda de crecimiento sostenible, con sentido social, económico, político, cultural, ético y moral. El Centro Educativo Superior más importante que tiene Riohacha es la Universidad de La Guajira (UNIGUAJIRA), creada en 1976 como unestablecimiento público de carácter universitario, y se pretende establecer un diagnóstico para la evaluación de las necesidades, posicionamiento y tendencias de los profesionales egresados. Partiendo de 580 empresas activas, se diseño una muestra aleatoria y una encuesta. En el procesamiento de ia información se usaron los procedimientos estadísticos de tablas de frecuencia univariadas, gráficos de pastel, dócimas de comparación de proporciones y en caso necesario la dócima de comparaciones múltiples de Tukey, la Taxonomía numérica para clasificar los programas de la UNIGUAJIRA, de acuerdo con el posicionamiento y el número de profesionaies por cada programa, utilizando el método del vecino más cercano y el cuadrado de la distancia euclidiana. El estudio de las hojas de vida de los profesionales es el criterio fundamentai utilizado por las empresas y de los programas que oferta la UNIGUAJIRA, el de Administrador de Empresas es el mejor en posicionamiento y en cuanto al número de profesionales. Se manifestaron necesidades por programas de Comercio Exterior, Salud y Ciencias del Mar, entre otros. [ABSTRACT FROM AUTHOR] more...

The work was carried out with the objective of determining how often the centrifugal pumps for industrial silage production have to work in the "Héctor Molina" plant of the Municipality of San Nicolás de Bari in Mayabeque, Cuba. That technology was developed by the Institute of Animal Science (ICA) and it uses by-products and wastes from the sugar industry and agricultural production for animal feed. To determine the frequency, the sedimentation rate (v) of the solids in the liquid raw materials (thermolised Saccharomyces cerevisiae yeast cream, concentrated vinasse) and the silage feed was calculated. For that, three experiments were carried out, each one with 10 graduated test tubes. Initial height of each test tube and height of descendant interfaces at different time intervals were measured and the behavior of the variable sedimentation vs. time was analyzed with statistical criteria. It was obtained that the (v) of the vinasse, cream and silage are 1,58 E-6 m/s, 2,76 E-07 m/s, and 1,55 E-07m/s, respectively. It is concluded that the centrifugal pump must recirculate the vinasse and the cream to maintain a stable chemical composition every 4 h and 12 h. The silage should be recirculated every 58 h to facilitate the extraction of the final product from the silos and the model that best describes the sedimentation of CSF is the quadratic model. [ABSTRACT FROM AUTHOR] more...