El bambú (Guadua angustifolia spp.) como alternativa de conducción para un sistema de riego por multicompuertas

The present investigation aimed to use bamboo as a pipeline for a multi floodgates irrigation system in areas where this plant species abounds. Hydraulically characteristics, such as the roughness, speed, its maximum working pressure were determined in the laboratory and field; likewise, a guide was prepared for the selection of the bamboo’s diameters under the conditions of slope and pressure load. The rugosity study of the material was carried out by the Colebrook - White equation, obtaining an absolute rugosity of 0,0161 meters, the Hazen - Williams roughness coefficient getting 50 and the Manning’s roughness coefficient of 0,0232. The study also compared the results of load loss estimated by the three methods, versus the values obtained in the laboratory and statistical indicators (the mean square error and the coefficient of efficiency), these indicators did not present significant differences. Also, that from speeds higher than 0,8 ms -1 , the behavior of the load loss potentially increases and it was found that the bamboo supports pressures up to 30 PSI or 20 mwc.La presente investigación tuvo como objetivo el uso del bambú como tubería de conducción para un sistema de riego por multicompuertas en zonas donde abunda esta especie vegetal. Se analizaron las características hidráulicas como la rugosidad, velocidad y la máxima presión de trabajo en el laboratorio y campo; asimismo, se elaboró una guía para la selección de diámetros en condición de pendiente y carga de presión. El estudio de la rugosidad del material se obtuvo mediante la ecuación de Colebrook-White, una rugosidad absoluta de 0,0161 m, el coeficiente de rugosidad de Hazen-Williams de 50 y el coeficiente de rugosidad de Manning de 0,0232. Se comparó los resultados de las pérdidas de carga estimadas por los tres métodos versus los valores obtenidos en el laboratorio y mediante indicadores estadísticos (error cuadrático medio y coeficiente de eficiencia), estos indicadores no presentaron diferencias significativas. También, a partir de velocidades superiores a 0,8 ms-1, el comportamiento de la pérdida de carga aumenta potencialmente y se encontró que el bambú soporta presiones de hasta 30 PSI o 20 mca

Factores asociados al rendimiento académico de los estudiantes del centro de estudios preuniversitarios de la Universidad Nacional Agraria La Molina

The purpose of this study was to identify the factors associated with academic performance of students in Pre University Studies Center of the UNALM during the 2011-I term on the following subjects: Verbal Reasoning, Mathematical Reasoning, Algebra, Arithmetic, Geometry, Trigonometry, Physics, Chemistry and Biology. According to the statistical results of the multilevel model, it was found that the type of enrollment in CEPRE-UNALM is associated with the performance of all courses offered in the CEPRE-UNALM, gender is associated with the performance in Geometry, number of cycles in the CEPRE-UNALM is associated with the performance of all courses except Verbal Reasoning, school of origin is associated with the performance of Arithmetic, Verbal Reasoning and Mathematical Reasoning and the type of teacher is associated with the performance of Physics, Algebra, Chemistry and Biology.El propósito de este estudio fue identificar los factores asociados al rendimiento académico de los estudiantes del Centro de Estudios Preuniversitarios de la Universidad Nacional Agraria La Molina – UNALM, del ciclo del 2011-I, en los cursos de Razonamiento Verbal, Razonamiento Matemático, Algebra, Aritmética, Geometría, Trigonometría, Física, Química y Biología. De acuerdo con los resultados estadísticos del modelo multinivel, se encontró que el  tipo de matrícula en el Centro de Estudios Preuniversitarios (CEPRE-UNALM) se encuentra asociado al rendimiento de todos los cursos que se desarrollan en el Centro; el género se encuentra vinculado al rendimiento en Geometría; el número de ciclos se encuentra relacionado con el rendimiento en todos los cursos menos en el de Razonamiento Verbal; el  colegio de procedencia se encuentra asociado al rendimiento de los cursos de Aritmética, Razonamiento Verbal y Razonamiento Matemático y el tipo de profesor en el aula se encuentra vinculado al rendimiento de los cursos de Física, Algebra, Química y Biología

Evaluation of 10 AMD Associated Polymorphisms as a Cause of Choroidal Neovascularization in Highly Myopic Eyes

<div><p>Choroidal neovascularization (CNV) commonly occurs in age related macular degeneration and pathological myopia patients. In this study we conducted a case-control prospective study including 431 participants. The aim of this study was to determine the potential association between 10 single nucleotide polymorphisms (SNPs) located in 4 different genetic regions (<i>CFI</i>, <i>COL8A1</i>, <i>LIPC</i>, and <i>APOE)</i>, and choroidal neovascularization in age-related macular degeneration and the development of choroidal neovascularization in highly myopic eyes of a Caucasian population. Univariate and multivariate logistic regression analysis adjusted for age, sex and hypertension was performed for each allele, genotype and haplotype frequency analysis. We found that in the univariate analysis that both single-nucleotide polymorphisms in <i>COL8A1</i> gene (rs13095226 and rs669676) together with age, sex and hypertension were significantly associated with myopic CNV development in Spanish patients (p<0.05). After correcting for multiple testing none of the polymorphisms studied remained significantly associated with myopic CNV (p>0.05); however, analysis of the axial length between genotypes of rs13095226 revealed an important influence of COL8A1 in the development of CNV in high myopia. Furthermore we conducted a meta-analysis of <i>COL8A1</i>, <i>CFI</i> and <i>LIPC</i> genes SNPs (rs669676, rs10033900 and rs10468017) and found that only rs669676 of these SNPs were associated with high myopia neovascularization.</p></div