Abstract This paper introduces an effective optimization approach to investigate the morphological effects of nanocomposite gel electrophoresis and operational parameters (see below) by integrating the numerical simulations based on finite element method and population-based search algorithm such as differential evolution. Simulations are performed to study the solute transport by Convection-Diffusion-Electromigration in a microvoid with axially varying cross-section. Morphological parameters such as channel shape and size, as well as operational parameters such as pressure gradient in the axial direction, and electric field in the orthogonal direction were considered and found to have considerable effects on the separation resolution in electrophoresis. Key observations on the most favorable hydrogel morphology for an efficient electrophoresis separation are presented.

Objective: To determine the trend of high school students from Valparaíso Chile by means of an anthropometrical somatotype. Material and methods: two samples of students during the years 1984-1985 (86 men and 71 women) and 2009-2010 (77 men and 86 women) between 15 and 18 years of age have been studied. Somatotype was estimated by the Heath-Carter anthropometric method. Results: significant differences were found in all the variables of the somatotype during the periods studied (p < 0.01), except for height (p = 0.176) and humeral breadth in women (p = 0.067). Important distinctions were also found in the endomorphic, mesomorphic and ectomorphic components (p < 0.01). Men measurements registered remarkable differences in all the variables (p < 0.01), with the exception of weight (p = 0.156), calf breadth (p = 0.906) and arm breadth in contraction (p = 0.284). Measurement results of endomorphic (p < 0.01), ectomorphic (p < 0.01) and mesomorfic components (p < 0.05) revealed considerable differences. During the period 1984-1985, men classified as balanced mesomorph 2.7-4.8-3.1 which switched to mesomorph-endomorph 3.8-4.3-2.5 in the period 2009-2010. And the population of women in the 1984-1985 period is classified as mesomorph-endomorph 4.2-4.7-2.1 and changes to a mesomorphic-endomorph biotype 6.6-4.1-1.3 in the 2009-2010. Conclusions: the somatotype of the adolescent population, especially women in Valparaiso, Chile has changed to a predominant endomorphic biotype, and its mesomorphic component has decreased. A high relative adiposity contributes to increase the probability for these people to suffer non-transmissible chronic diseases and cardiovascular issues.

Objetivo: Determinar la tendencia de una población de estudiantes de educación secundaria de Valparaíso, Chile a través del somatotipo. Material y métodos: Se han estudiado dos muestras de estudiantes durante los períodos 1984-1985 (hombres 86 y mujeres 71) y 2009-2010 (hombres 77 y mujeres 86) de 15 a 18 años. Se registraron los datos antropométricos para evaluar el somatotipo antropométrico de Heath-Carter. Resultados: Para todas las variables del somatotipo de Heath-Carter se encontraron diferencias significativas entre los períodos estudiados (p < 0,01) excepto para talla (p = 0,176) y diámetro humeral (p = 0,067) en mujeres, para los componentes endomorfo, mesomorfo y ectomorfo también se registran diferencias significativas (p < 0,01). En hombres, se registran diferencias significativas para todas las variables (p < 0,01) con excepción de peso (p = 0,156), perímetro de pierna (p=906) y perímetro de brazo en contracción (p = 0,284). También se observan diferencias significativas en los componentes endomorfo (p < 0,01), ectomorfo (p < 0,01) y mesomorfo (p < 0,05). La población de mujeres del periodo 1984-1985 se clasifica como endomorfo-mesomorfo 4,2-4,7-2,1 y cambia a un perfil endo-mesomórfico 6,6-4,1-1,3 en el 2009-2010. En los hombres en el periodo 1984-1985 se clasifica como mesomorfismo balaceado 2,7-4,8-3,1 y cambia a un endomorfo-mesomorfo 3,8-4,3-2,5 en el periodo 2009-2010. Conclusiones: El somatotipo de la población de adolescentes de Valparaíso, Chile se ha desplazado hacia un biotipo predominantemente endomorfo sobre todo en mujeres y ha disminuido su componente mesomórfico. Este perfil con una alta adiposidad relativa contribuye a aumentar las probabilidades de que esta población sufra enfermedades crónicas no transmisibles y cardiovasculares.

This contribution focuses on the analysis of the role of Joule heating on the hydrodynamics of systems where buoyancy is an important driving force. Typical examples are electrokinetic applications for soil cleaning and macromolecules separation. In particular, the region of interest for this study is the zone near vertical-rectangular electrodes. The analysis is conducted for boundary layer flows due to natural convection as a result of heat generation caused by the applied electrical field. A numerical solution of the differential model equations yields the temperature profile, the boundary layer thickness, and the component of the velocity field along the axial and transversal directions of the electrode. Effects of the heat generation on temperature, velocity profiles and boundary layer thickness are simulated and discussed. The results of the analysis allow a better assessment of the role of Joule heating on the hydrodynamics of the system near the electrode.

The objective of this study was to standardize the enzymatic procedure for estimating the digestibility of forages using the fungal cellulase Penicillium funiculosum, and its comparison with the Tilley and Terry (1963) in vitro digestibility method. The well- known in vitro digestibility of alfalfa and oat straw were used for the standardization of the technique. Different quality forages from various locations of Peru were used for the comparison between methods. The best enzyme-substrate concentrations were 200 and 250 mg respectively. Both methods were statistically different, being the enzymatic digestibility values lower than the in vitro method ones. The correlation coefficient between methods was 0.987 (p<0.001). The enzymatic digestibility method proved to be a simple and rapid laboratory analysis for the evaluation of forages.

El objetivo de este estudio fue estandarizar un método enzimático para medir la digestibilidad de forrajes empleando la enzima celulasa proveniente del hongo Penicillium funiculosum y compararlo con el método de digestibilidad in vitro de Tilley y Terry (1963). Para la estandarización de la técnica se utilizó como sustrato forrajes de digestibilidad in vitro conocida: alfalfa y paja de avena; y para la comparación entre métodos se utilizó forrajes de diferente calidad provenientes de varias zonas del Perú. La concentración óptima enzima-sustrato hallada fue de 200 y 250 mg, respectivamente. Los valores de digestibilidad del método enzimático fueron estadísticamente menores que los del método in vitro, y el coeficiente de correlación fue de 0.987 (p<0.001). El método de digestibilidad enzimática demostró ser un procedimiento de laboratorio simple y rápido para la evaluación de los forrajes.

The Joule heating effects on hydrodynamics are examined for the case of a non-Newtonian fluid flowing in a batch electrophoretic cell. The potential benefits of using non-Newtonian fluids in electrophoretic separations could lead, for example, to an increase in the efficiency of separations and to a better scale-up of the operation for the processing of large quantities on a pilot or even an industrial scale. The analysis conducted in this research is based on the formulation of simplified mathematical models that can capture the most relevant aspects of the physics of the free convection that takes place in a batch electrophoretic cell. The first aspect is associated with the carrier fluid when no solute sample (of particles or macromolecules) is added to the device. This is, indeed, a carrier fluid completely free of solute problem. This aspect of the research is referred to as the carrier fluid problem. The second aspect involved in the investigation is the analysis of the mass transport (i.e., convective-diffusive) process associated with the motion of a solute sample added to the carrier fluid. This particular aspect of the research is referred to as the solute problem of the free-convection electrophoretic cell. The two problems are sequentially coupled and the solution of the carrier fluid problem must be performed first in order to have the velocity profile to study the solute problem. Details about hydrodynamic considerations and the solution approach are discussed in this contribution.

The problem of the effect of Joule heating generation on the hydrodynamic profile and the solute transport found in electrophoretic devices is addressed in this article. The research is focused on the following two problems: The first one is centered around the effect of Joule heating on the hydrodynamic velocity profile and it is referred to as "the carrier fluid problem." The other one is related to the effect of Joule heating on the solute transport inside electrophoretic cells and it is referred to as "the solute problem". The hydrodynamic aspects were studied first to yield the velocity profiles required for analysis of the solute transport problem. The velocity profile obtained in this study is analytical and the results are valid for non-Newtonian fluids carriers. To this end, the power-law model was used to study the effect of the rheology of the material in conjunction with the effect of Joule heating generation inside batch electrophoretic devices. This aspect of the research was then effectively used to study the effect of Joule heating generation on the motion of solutes (such as macromolecules) under the influence of non-Newtonian carriers. This aspect of the study was performed using an area-averaging approach that yielded analytical results for the effective diffusivity of the device.