X-Ray Fluorescence Analysis of Ground Coffee

Coffee is becoming one of the most popular beverages in Mexico. In the present work, X-ray Fluorescence (XRF) was used to determine the contents of several elements (with atomic numbers between 11 and 38) in 11 samples of commercial ground coffee, comparing with another one of soluble coffee and two of used ground coffee. Samples were dried at room temperature and pelletized. XRF analyses were carried out using a spectrometer based on an Rh X-ray tube, registering the characteristic x-rays with a Silicon Drift Detector. The system detection calibration and accuracy check was performed through the analysis of NIST certified reference materials 1547 (peach leaves), 1570a (spinach leaves), 1573a (tomato leaves), and 1571 (orchid leaves). As a general rule, the elemental concentrations measured are similar in all samples of coffee, in values not exceeding toxic levels. However, the differences among the elemental concentrations are shown

ESTUDIO COMPARATIVO DEL DESARROLLO DE LA ALFABETIZACIÓN EN POBLACIONES DE EDUCACIÓN PRIMARIA Y PREESCOLAR

A comparative study about early literacy of 33 children from elementary school and 27 children from kindergarden was carried out, applying the Instrumento de Observación de los Logros de la Lectoescritura Inicial (Escamilla, Andrade, Basurto y Ruíz, 1996). The purpose of the present work was to characterize the level of early literacy considering the knowledge of the language written in both groups. The groups were evaluated in the first two weeks of the month of September and of October of the school cycle 2011-2012. In the results it was observed that they were only significant differences in the identification of letters. The results are discussed in relation to the concept of early literacy

Vesicle formation induced by thermal fluctuations

The process of fission and vesicle formation depends on the geometry of the membrane that will split. For instance, a flat surface finds it difficult to form vesicles because of the lack of curved regions where to start the process. Here we show that vesicle formation can be promoted by temperature, by using a membrane phase field model with Gaussian curvature. We find a phase transition between fluctuating and vesiculation phases that depends on temperature, spontaneous curvature, and the ratio between bending and Gaussian moduli. We analysed the energy dynamical behaviour of these processes and found that the main driving ingredient is the Gaussian energy term, although the curvature energy term usually helps with the process as well. We also found that the chemical potential can be used to investigate the temperature of the system. Finally we address how temperature changes the condition for spontaneous vesiculation for all geometries, making it happen in a wider range of values of the Gaussian modulus.Comment: 31 pages, 10 figure

Anomalous Hall conductivity control in Mn3_3NiN antiperovskite by epitaxial strain along the kagome plane

Antiferromagnetic manganese-based nitride antiperovskites, such as Mn$_3$NiN, hold a triangular frustrated magnetic ordering over their kagome lattice formed by the Mn atoms along the (111)-plane. As such, frustration imposes a non-trivial interplay between the symmetric and asymmetric magnetic interactions, which can only reach equilibrium in a noncollinear magnetic configuration. Consequently, the associated electronic interactions and their possible tuning by external constraints, such as applied epitaxial strain, play a crucial role in defining the microscopic and macroscopic properties of such topological condensed matter systems. Thus, in the present work, we explored and explained the effect of the epitaxial strain imposed within the (111)-plane, in which the magnetic and crystallographic symmetry operations are kept fixed, and only the magnitude of the ionic and electronic interactions are tuned. We found a linear shifting in the energy of the band structure and a linear increase/decrease of the available states near the Fermi level with the applied strain. Concretely, the compression strain reduces the Mn-Mn distances in the (111) kagome plane but linearly increases the separation between the stacked kagome lattices and the available states near the Fermi level. Despite the linear controlling of the available states across the Fermi energy, the anomalous Hall conductivity shows a non-linear behavior where the $\sigma_{111}$ conductivity nearly vanishes for tensile strain. On the other hand, $\sigma_{111}$ fetches a maximum increase of 26\% about the unstrained structure for a compression value close to $-$1.5\%.This behavior found an explanation in the non-divergent Berry curvature within the kagome plane, which is increased for constraining but significantly reduced for expansion strain values..

A GEANT4 Study of a Gamma-ray Collimation Array

Proton beam therapy uses high-energy protons to destroy cancer cells which are still uncertain about where in the body they hit. A possible way to answer this question is to detect the gamma rays produced during the irradiation and determine where in the body they are produced. This work investigates the use of collimators to determine where the proton interactions occur. GEANT4 is used to simulate the gamma production of a source interacting with a collimator. Each event simulates a number of gammas obtained as a function of the position along the detector. Repeating for different collimator configurations can thus help determine the best characteristics of a detector device

Application of work study to process improvement: fruit nectar case

Work study is an extensively used technique for examining the methods to carry out activities in a company and proposing actions for productivity improvement. This paper presents a work-study application to a fruit nectar process inside a food company using 5W1H and ECRS techniques. A critical analysis was conducted in three previously selected activities, according to its improvement potential. Results allowed optimizing distances along the process and improving ergonomic conditions for workers. Savings included a total distance of 10.2 m, two transportation activities and two delays activities per production cycle. Also, the standard time was determined in one of the prioritized activities. Our results demonstrated that work study techniques are tools suitable to be implemented in most economic sectors for productivity improvements. However, the technique itself will not be effective without a commitment from top-level management for implementing the corrective actions proposed

Factores asociados con la implementación de Buenas Prácticas Ganaderas en pequeños productores ovinos del postconflicto colombiano

The signing of the peace agreement between the Revolutionary Armed Forces of Colombia and the Colombian government brought a change in the social dynamics of rural regions of Colombia that has affected small sheep producers in post-conflict regions. The aim of this study was to identify the sociodemographic factors that affect the implementation of Good Agricultural Practices (GAP) in extensive sheep systems in the Colombian post-conflict and their relationship with some health, production and economic indicators. Thirteen sheep farms located in Marulanda, Colombia were evaluated. The implementation of the GAP was determined through a structured evaluation instrument based on Colombian legislation (Res. 20277 of 2018). In addition, a sample of sheep under 1 year of age was taken from each farm to conduct clinical examinations and laboratory analysis to obtain sanitary indicators. Age (β=-0.31, p=0.04), secondary education level (β=7.91, p=0.05) and income (β=5.29, p=0.04) determined the adoption of practices contained in the GAP and these were translated in productive, sanitary and economic benefits such as the increase in the price of the live animal (r=0.85, p<0.001), weight at slaughter (r=0.57, p<0.05), hematocrit (r=0.64, p<0.05), low prevalence of Eimeria spp (r=-0.71, p<0.001) and age at slaughter (-0.74, p<0.001). The implementation of GAP in ovine systems of the Colombian post-conflict represents productive advantages; however, the age, education and economic income of the producers influence such implementation.La firma del acuerdo de paz entre las Fuerzas Armadas Revolucionarias de Colombia y el gobierno colombiano trajo consigo un cambio en las dinámicas sociales de las regiones rurales de Colombia que ha afectado a los pequeños productores ovinos en regiones del posconflicto. El objetivo de este estudio fue identificar los factores sociodemográficos que afectan la implementación de las Buenas Prácticas Ganaderas (BPG) en sistemas ovinos extensivos del posconflicto colombiano y su relación con algunos indicadores sanitarios, productivos y económicos. Trece granjas ovinas ubicadas en Marulanda, Colombia fueron evaluadas. La implementación de las BPG fue determinada mediante un instrumento estructurado de evaluación basado en la legislación colombiana (Res. 20277 de 2018). Además, se tomó muestra de ovinos menores de 1 año de cada granja para realizar un examen clínico y análisis de laboratorio para obtener indicadores sanitarios. La edad (β=-0.31, p=0.04), nivel educativo secundario (β=7.91, p=0.05) e ingresos económicos (β=5.29, p=0.04) determinaron la adopción de prácticas contenidas en las BPG y estas se tradujeron en beneficios productivos, sanitarios y económicos como el aumento del precio del animal en pie (r = 0.85, p<0.001), el peso al sacrificio (r=0.57, p<0.05), el hematocrito (r=0.64, p<0.05) y la baja prevalencia de Eimeria spp (r=-0.71, p<0.001) y edad al sacrificio (-0.74, p<0.001). La implementación de BPG en sistemas ovinos del postconflicto colombiano representa ventajas productivas; sin embargo, la edad, educación e ingresos económicos de los productores influencian dicha implementación

Pesquisa participativa em melhoramento de mandioca: uma experiência no Semi-Árido do Nordeste do Brasil.

Este trabalho teve por objetivos provar conjuntamente com agricultores, extensionistas e pesquisadores uma metodologia complementar, denominada de pesquisa participativa em melhoramento de mandioca, que aplicada a clones em etapas avançadas de avaliação, incremente a possibilidade de serem adotados pelos produtores, bem como estabelecer uma retroalimentação entre estes segmentos que permita identificar os principais critérios de seleção utilizados pelos produtores do semi-árido para a adoção de novas cultivares de mandioca. O trabalho foi desenvolvido em quatro locais do semi-árido dos Estados da Bahia (Itaberaba), Pernambuco (Petrolina e Araripina) e Ceara (Quixadá), em parceria com a EBDA,IPA e EPACE. Iniciou-se com um diagnostico, seguido do planejamento e implantação das provas participativas, avaliação e retro informação. Foram estabelecidas dezessete provas participativas, nos anos de 1993/94, com nove clones selecionados para as condições semi-áridas. Como resultados principais traçou-se o perfil de uma variedade ideal para o semi-árido, baseado nos critérios de seleção estabelecidos pelos produtores dessa região, formou-se um glossário sobre a terminologia agrícola local do produtor de mandioca e adaptou-se um livro de campo gerado no CIAT, as características consideradas importantes pelos produtores de mandioca do semi-árido.bitstream/item/81301/1/Pesquisa-Participativa-Wania-Fukuda-Documentos-73-1997.pd