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Search Results: 1 - 10 of 603606 matches for " Manuel Guía Calderón "
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Caracterización eléctrica de tejido sanguíneo mediante función de transferencia Caracterización eléctrica de tejido sanguíneo mediante función de transferencia
José Francisco Gómez Aguilar,J. Jesús Bernal Alvarado,J. Juan Rosales García,Manuel Guía Calderón
Acta Universitaria , 2012,
Abstract: This paper presents an analysis and modeling of electrical impedance spectra applied to the study of experimental data of blood tissue and its main components: red cells, white and plasma. Using the electrical circuit theory yields the transfer functions and the graphic representation of Bode and Nyquist. You can see in this work the experimental technique’s potential to differentiate cellular components of blood tissue, and the usefulness of developing accurate models for analysis. En este trabajo se presenta un análisis y modelado de espectros de impedancia eléctrica aplicados al estudio de datos experimentales de tejido sanguíneo y sus principales componentes: glóbulos rojos, blancos y plasma. Usando la teoría de circuitos eléctricos se obtienen las funciones de transferencia y la representación gráfica de Bode y Nyquist. Se puede ver en este trabajo el potencial de la técnica experimental para diferenciar los elementos que forman al tejido sanguíneo, así como la utilidad de desarrollar modelos precisos para su análisis.
Oscilaciones de un sistema dinámico no lineal analizando sus bifurcaciones Oscilaciones de un sistema dinámico no lineal analizando sus bifurcaciones
José Francisco Gómez Aguilar,Lorena Guadalupe González Juárez,J. Juan Rosales García,Manuel Guía Calderón
Acta Universitaria , 2012,
Abstract: En este trabajo se analizan las oscilaciones de un sistema eléctrico de potencia acopladocon un horno de arco eléctrico. Se presentan los diagramas de bifurcación y la estabilidadde los puntos de equilibrio. Los puntos críticos de estabilidad y las zonas de operación seanalizan en el estado oscilatorio, se obtiene que en el voltaje interno del generador síncronose presenta el parámetro de bifurcación. In this paper the oscillations of an electrical power system coupled to an electric arcfurnace are analyzed. Bifurcation diagrams and the stability of the equilibrium pointsare presented. The critical stability points and the operating zones are analyzed in theoscillatory state, and it is found that the internal voltage of the synchronous generatorshows the bifurcation parameter.
EL PROCESO DE CONSTRUCCION Y VALIDACION DE LA ESCALA DE IDENTIFICACION DE TALENTO ACADEMICO 'EDITA'
Alegría,Isabel; lay,Siu-lin; Calderón,Carlos; Cárdenas,Manuel;
Estudios pedagógicos (Valdivia) , 2010, DOI: 10.4067/S0718-07052010000200001
Abstract: the main objective of this study was the construction and validation of the academic talent's identification scale (edita), based on the self-report of the characteristics associated with that construct. for this purpose, a sample of 268 students was chosen, 127 of fifth elementary year and 141 of the freshman year. those students were attending public, subsidized and private schools in antofagasta city. the results obtained through the analysis of data indicate that the scale could be considered valid and reliable to detect the characteristics associated with the academic talent in the above mentioned population.
Utilización del aprendizaje basado en problemas en la ense anza de física en estudiantes de medicina. Comparación con ense anza tradicional Problem based learning in physics. Comparison with traditional teaching in medical students
Eduardo Fasce H,María Calderón B,Luis Braga I,Manuel De Orúe R
Revista médica de Chile , 2001,
Abstract: Background: Problem based learning, integrating basic science with clinical problems, is one of the most recommended forms of teaching for medical schools. Aim: To compare a problem based learning program for physics with traditional teaching methods. Material and methods: In the physics course, first year medical students were separated in groups with traditional learning and problem based teaching. Both groups were subjected to the same knowledge and qualitative evaluations. Results: At the end of the course, cognitive performance in both groups was similar (60.8 and 61.3% among traditional teaching and problem based learning groups respectively). However, students assigned to the problem based learning group evaluated significantly better the teaching methodology and process. Conclusions: Physics education, using problem based learning, obtains the same cognitive results but a higher degree of satisfaction than traditional teaching among students (Rev Méd Chile 2001; 129: 1031-7)
EL PROCESO DE CONSTRUCCION Y VALIDACION DE LA ESCALA DE IDENTIFICACION DE TALENTO ACADEMICO 'EDITA' O Processo de Constru o e Valida o da Escala de Identifica o do Talento Acadêmico 'Edita' The Process of Construction and Validation of the Academic Talent's Identification Scale 'Edita'
Isabel Alegría,Siu-lin lay,Carlos Calderón,Manuel Cárdenas
Estudios Pedagógicos (Valdivia) , 2010,
Abstract: El objetivo principal de este estudio fue la construcción y validación de una escala de identificación de Talento Académico (Edita), basada en el autorreporte de las características asociadas a dicho constructo. Para ello se seleccionó una muestra compuesta por 268 estudiantes, 127 de quinto a o básico y 141 de primer a o medio, los que pertenecían a establecimientos educacionales municipalizados, subvencionados y particulares de la ciudad de Antofagasta. Los resultados obtenidos en el análisis de datos indican que sería una escala válida y confiable para detectar las características asociadas al Talento Académico en dicha población. O principal objetivo deste estudo foi a constru o e valida o de uma escala de identifica o do Talento Acadêmico (Edita), baseada no auto-informe das características associadas a tal constructo. Para isso, selecionou-se uma mostra composta por 268 estudantes, 127 de quinto ano básico e 141 de primeiro ginásio, os quais pertenciam a estabelecimentos educacionais municipalizados, subsidiados e privados da cidade de Antofagasta. Os resultados obtidos na análise dos dados indicam que seria uma escala válida e confiável para detectar as características associadas ao Talento Acadêmico naquela popula o. The main objective of this study was the construction and validation of the Academic Talent's Identification Scale (Edita), based on the self-report of the characteristics associated with that construct. For this purpose, a sample of 268 students was chosen, 127 of fifth elementary year and 141 of the freshman year. Those students were attending public, subsidized and private schools in Antofagasta city. The results obtained through the analysis of data indicate that the scale could be considered valid and reliable to detect the characteristics associated with the Academic Talent in the above mentioned population.
Analysis of Equivalent Circuits for Cells: A Fractional Calculus Approach
Gómez-Aguilar F.,Rosales-García J.,Guía-Calderón M.,Bernal-Alvarado J.
Ingeniería, investigación y tecnología , 2012,
Abstract: Fractional order systems are considered by many mathematicians the systems of the XXI century. The reason is that nature has proved to be best described in terms of systems composed of fractional order derivatives. This emerging area of research is slowly gaining more strength in engineering, biochemistry, medicine, biophysics, among others. This paper presents an analysis in the frequency domain equivalent of cellular systems described by equations of integer and fractional order; it also carries out an analysis in time domain in order to display the memory capacity of fractional systems. It presents the fractional differential equations equivalent models and simulations comparing integer and fractional order.
Cirugía de rescate (reubicación quirúrgica) en segundos molares inferiores impactados
García Calderón,Manuel; Torres Lagares,Daniel; González Martín,Maribel; Gutiérrez Pérez,José Luis;
Medicina Oral, Patología Oral y Cirugía Bucal (Ed. impresa) , 2005,
Abstract: the impaction of lower second molars, given that its incidence is 0.03 to 0.21%, is a rare complication in tooth eruption. it has been detected more often in unilateral form than bilateral and is more common in the mandible than in the maxillary. it has a slight predilection for males, and mesial inclination is more usual. a wide variety of therapeutic approaches have been published, basically referring to surgical techniques, independent or complemented by means of orthodontic technical aids, with the aim of placing the tooth in the correct position, and which are encompassed under the concept of surgical rescue. in cases resolved with repositioning of an impacted tooth, prophylactic root extraction has been proposed as obligatory. we present a case of a 12 and a half year old patient referred to the university of seville due to non-eruption of the left lower second molar. the patient was referred by her orthodontist, who detected the impaction before starting orthodontic treatment. the orthodontist requested that, if it was possible, we did not extract the root of the third molar, because its eruption would be feasible in the future (there would be sufficient space in the arch). the spaces available were measured and we decided to attempt the repositioning of the impacted tooth without extracting the root of the wisdom tooth, which was carried out successfully.
Artificial chinampas soils of Mexico City: their properties and salinization hazards Suelos artificiales de chinampas de la Ciudad de México: propiedades y riesgos de salinización Solos artificiais da cidade do México- Chinampas: propriedades e riscos de saliniza ao
Pavel Krasilnikov,Rosalía Ramos Bello,Norma Eugenia García Calderón,Héctor Manuel Ortega Escobar
Spanish Journal of Soil Science , 2011, DOI: 10.3232/sjss.2011.v1.n1.05
Abstract: The chinampas agriculture is a traditional land use practice in the Valley of Mexico since Pre-Hispanic time. The chinampas soils were constructed by excavation of lake sediments that resulted in the creation of a system of islands separated by channels. The agricultural productivity of these artificial soils was high; also the land use practices included forestry, fish breeding and hunting. Nowadays, the chinampas soils are affected by excessive salinity. We studied 10 representative soil profiles in the chinampas zone of Mexico City in order to characterize their properties and origin, to provide their classification, and to evaluate soil salinization, vertical distribution of the salts and their chemical composition. The soils are characterized by a layered structure, uniform dark grey colour, irregular vertical distribution of organic carbon and clay, and high percentage of carbon. Some soils show an increase in organic matter with depth, and other profiles have maximum organic matter content in the surficial layers and in the subsoil. The dynamics of sedimentation resulted in the decrease in organic matter in the upper layers of lacustrine sediments, because of recent increase in erosion rate and consequent increase in the proportion of mineral particles in the sediments. Most probably high organic matter content in surficial layers of some soils is due to excavation and accumulation of organic-rich subsoil material in the course of digging the channels. The concentration of soluble salts in superficial horizons, expressed as electric conductivity, varies in a wide range from 5 to almost 50 dS·m-1. The salts concentrate mainly in the superficial layers of soils. The abundance of the cations of soluble salts is Na+>Mg2+>Ca2+>K+ and that of the anions is SO42->Cl->HCO3->CO32-. The alkaline reaction of soils is caused by exchangeable Na rather than by free sodium carbonates. The restoration of chinampas requires a complex approach, combining soil, water and ecosystems remediation. La agricultura de chinampas es una práctica tradicional de uso del suelo en el Valle de México desde la época prehispánica. Los suelos de chinampas fueron construidas por la excavación de sedimentos del lago que resultó en la creación de un sistema de islas separadas por canales. La productividad agrícola de estos suelos artificiales fue alta; también las prácticas de uso del suelo incluyeron la silvicultura, la pesca y la caza. Actualmente, los suelos de chinampas están afectados por una salinidad excesiva. Se estudiaron 10 perfiles de suelos representativos de la zona de ch
Aplicación de la prueba de tecleo en la enfermedad de Parkinson
Cobas Rodríguez,Manuel Iván; Anías Calderón,José Manuel; Chao González,Susana; Cuza Ferrer,Yordanka; García Ojalvo,Irina;
Revista Cubana de Investigaciones Biom??dicas , 2007,
Abstract: diagnostic tests as the reiterated typing test at time intervals of 1 minute were made to corroborate the presence of alterations in the dopamine via. when this test is made in a conventional computer, there may be errors as the overregister that would alter its results. that's why, a computer program was proposed to guarantee the correct execution and the adequate processing of the results. to demonstrate the diagnostic capacity of of this program, 30 sound subjects and 30 parkinsonian patients without medication and after the administration of levodopa had the test. it was confirmed that the motor response in the typing test was significantly lower in parkinsonian patients compared with controls, in both hands, and that after administering levodopa to the patients, the change speed in the stages of the typing test increased. it was considered that the typing test allows an objective assessment of the functionality of the dopamine via in patients with parkinson's disease.
ESTANDARIZACIóN DE UN MéTODO ANALíTICO PARA EXTRACCIóN Y CUANTIFICACIóN DE CIPERMETRINA EN PASTOS
Cardona,Yaneth; Chaparro,Amanda L; Calderón,Lilia S; Peláez,Manuel J; García,Carlos H;
Revista Colombiana de Química , 2011,
Abstract: in this study, an analytical method has been developed to determine cypermethrin in grass matrices using direct immersion solid-phase microextraction (di-spme), coupled to gas chromatography with flame ionization detector (gc-fid). the optimized di-mefs experimental procedures to extract cypermethrin in grass matrix were: 5 g of the sample were heated with 10 ml of acetone 1% v/v in water during 10 min. 4 ml of this solution were used for extracting with a polydimethylsiloxane (pdms)-coated fiber at 60 °c and 500 rpm during 30 min. the analyte desorption was performed at 270 °c for 6 min. the proposed procedure showed linear behavior in the range tested (5-300 mg/l) with r2 of 0.999. the detection and quantification limits were 1.53 and 4.97 ng/ ml respectively with a standard deviation of 8.57% (n = 6). the method proposed in this paper allows determining cypermethrin in samples of grass to trace levels with a recovery of 99.08%.
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