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Search Results: 1 - 10 of 496003 matches for " Hugo Alberto González;Mejía "
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CORRELACIóN ENTRE PROPIEDADES ANATóMICAS, RESISTENCIA A FLEXIóN ESTáTICA Y ENERGíA REQUERIDA PARA EL CORTE DE LA CA?A DE AZúCAR (Saccharum officinarum L.)
González Sánchez,Hugo Alberto; Toro Betancur,Alejandro; álvarez Mejía,Fernando; Cortés Marín,Elkin Alonso;
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: the microstructure, anatomical structure, bending resistance and the energy required to cut stems of three varieties of sugar cane cultivated in the valle del cauca ( colombia ), were studied in order to have useful data for the development of cutting blades. microestructural and anatomical characterization tasks were performed by optical microscopy ( om), and scanning electron microscopy (sem). the physical and mechanical properties were determined after adaptation of astm standards (which were developed for wood), while the consumption of energy during cutting was evaluated by using a modified charpy type impact pendulum. the fibers and silica particles showed different geometry and distribution in the stems of the three studied varieties, and a relation was established between the microstructure of the stems and the energy required to cut them in the modified charpy pendulum. generally speaking, cutting the internodes required higher specific energy than cutting the nodes, and the use of blades with cutting angle of 20° led to lower levels of energy consumption. also, a relation of proportionality between the effective cross-sectional area of fibers (atef) and the specific energy consumed in cutting, as well as between the flexibility coefficient and the modulus of elasticity in bending were found.
CORRELACIóN ENTRE PROPIEDADES ANATóMICAS, RESISTENCIA A FLEXIóN ESTáTICA Y ENERGíA REQUERIDA PARA EL CORTE DE LA CA A DE AZúCAR (Saccharum officinarum L.) CORRELATIONS AMONG ANATOMIC PROPERTIES, BENDING RESISTANCE AND ENERGY REQUIRED TO CUT SUGAR CANE (Saccharum officinarum L.)
Hugo Alberto González Sánchez,Alejandro Toro Betancur,Fernando álvarez Mejía,Elkin Alonso Cortés Marín
Revista Facultad Nacional de Agronomía, Medellín , 2008,
Abstract: La microestructura, estructura anatómica, la resistencia a la flexión y la energía requerida durante el corte de los tallos de tres variedades de ca a de azúcar cultivadas en el Valle del Cauca (Colombia), fueron estudiados con el propósito de adquirir información útil para el desarrollo de cuchillas para corte de esta especie. Las labores de caracterización microestructural y anatómica se apoyaron en las técnicas de microscopía óptica y electrónica de barrido. Las propiedades mecánicas se determinaron adaptando algunas normas ASTM para maderas, mientras que la energía al corte se evaluó usando un péndulo de impacto tipo Charpy modificado. En los tallos de las tres variedades estudiadas se observaron diferentes distribuciones y dimensiones geométricas de las fibras y se verificó la presencia de partículas de sílice. Se presentó en general mayor requerimiento de energía específica al corte en los entrenudos que en los nudos y un menor consumo específico de energía al corte con las cuchillas con ángulo de afilado de 20°. Se establecieron relaciones entre la microestructura de los tallos, comportamiento a la flexión y al corte, destacándose la relación proporcional entre el área transversal efectiva de fibra (ATEF) y la energía específica al corte, así como entre el coeficiente de flexibilidad y el módulo de elasticidad en flexión. The microstructure, anatomical structure, bending resistance and the energy required to cut stems of three varieties of sugar cane cultivated in the Valle del Cauca ( Colombia ), were studied in order to have useful data for the development of cutting blades. Microestructural and anatomical characterization tasks were performed by optical microscopy ( OM), and scanning electron microscopy (SEM). The physical and mechanical properties were determined after adaptation of ASTM standards (which were developed for wood), while the consumption of energy during cutting was evaluated by using a modified Charpy type impact pendulum. The fibers and silica particles showed different geometry and distribution in the stems of the three studied varieties, and a relation was established between the microstructure of the stems and the energy required to cut them in the modified Charpy pendulum. Generally speaking, cutting the internodes required higher specific energy than cutting the nodes, and the use of blades with cutting angle of 20° led to lower levels of energy consumption. Also, a relation of proportionality between the effective cross-sectional area of fibers (ATEF) and the specific energy consumed in cutting, as well as between the fl
Variables físicas que explican la variabilidad de suelo aluvial y su comportamiento espacial
Jaramillo, Daniel Francisco Jaramillo;Gómez, María Luisa Anaya;Moná, Carlos Andrés Restrepo;Sánchez, Hugo Alberto González;Mejía, Fernando álvarez;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011001200017
Abstract: the objective of this work was to use the principal component and semivariance analyses to select physical variables that could explain the variability of an alluvial soil, in order to establish the spatial behavior of the chosen variables so that the location of experimental plots could be technically defined to study the abrasiveness effect on the wearing away of farm equipment. field tests were performed in 2008, on a 6,000 m2 flat lot with medium to heavy soil texture (vertic haplustepts). an intensive sampling was done in a grid of 10x14 m. the variables which had the most weight on the first three principal components were the contents of silt, fine and intermediate sand, intermediate gravel, soil moisture at field capacity, and the hygroscopic coefficient. except for the half sand and the field capacity, the other properties showed a high spatial dependence, and their distribution showed that in the experimental plot there are three sectors of differential accumulation of silt and fine sand. the combination of principal component analysis and geostatistics allowed for defining the soil properties involved in the wear of tools, their spatial pattern and the most appropriate way of distributing plots to study soil abrasiveness.
Validación de la Lista de Chequeo de Psicopatía-Revisada (PCL-R) en población carcelaria masculina de Colombia *
García Valencia,Jenny; Arango Viana,Juan Carlos; Correa Rico,Oscar; Pérez González,Andrés Felipe; Agudelo,Víctor Hugo; Mejía Mosquera,Carlos Andrés; Casals,Sergi; López Calle,Gabriel Jaime; Pati?o López,Juan David; Palacio Acosta,Carlos Alberto;
Revista Colombiana de Psiquiatría , 2008,
Abstract: introduction: psychopathy is characterized by a pattern of constant affective deficit and lack of respect for other people's rights and social norms. the psychopathy check-list revised (pcl-r) is an instrument of measurement composed of 20 items and it is one of the most used in psychopathy and antisocial personality disorder research. objective: to validate the pcl-r in colombian male inmates. methods: two translations into spanish and two back-translations for each of the items were done. the instruction manual was also translated into spanish and back-translated. face validity was assessed by a group of experts. content validity was examined as well as internal consistency, test-retest and inter-rater reproducibility. results: in the factor analysis for the content validity, four domains were found which explained 61.1% of the variance. the internal consistency was high (cronbach's alpha=0.94). similarly, the test-retest and inter-rater reproducibility were icc=0.83, 95% ci: 0.68-0.91 and icc=0.83, 95% ci: 0.86-0.96, respectively. conclusions: the spanish version of the pcl-r for colombian male jail inmates shows good psychometric properties.
Utilización de la morera Morus indica L. como reemplazo parcial del concentrado en la crianza de terneras
González Sandra Eugenia,Mejía Iván,Sánchez G. Hugo,Uribe Fernando
Acta Agronómica , 1995,
Abstract: Was made a technical and economical evaluation of three substitution levels of commercial concentrate (16% of crude protein) by fresh Mulberry Morus indica Leaves, in growing replacement calves. Thirty calves of the Lucerna breed, weighing an average of 30 kg were fed during 112 days by means of the restricted suckling system. The statical analysis was a complete random desing, with three treatments: 100 (T1) 75 (T2) and 50% concentrate (T3) two replicates were taken for each treatment and five calves were the experimental unit. The nutritional quality of Mulberry leaves was high, with 85.6% of dry matter degradability at 48 hours, 15.2% crude protein, 52 tonnes/ha/year with tour harvests per year and a cost of $137. I/kg of dry matter. The average weight gains were 0.406, 0.437, 0.406 kg/day and the concentrate consumptions 0.372, 0.207 and 0.115 kg/day, for T1 T2, and T3 respectively, with statistical difference (P<.05) for concentrate consumption. The Mulberry leaves consumption was 0.307 and 0.299 kg of D.M./day for T2 and T3, respectively. The economical analysis done by the partial budget technique indicated a net income of $190.864/calf for T2 followed for T3 with $185.027/calf and the for TI $178.109/calf. Se hizo una evaluación técnica y económica de tres niveles (T1:0, T2:25, y T3:50%) de sustitución de concentrado comercial (16% de PC) por hojas frescas de morera Monis indica en la cría de terneras de reemplazo. Se utilizaron 30 terneras de la raza Lucerna de cinco días (de edad) y peso promedio de 30 kg, durante 112 días alimentadas por el sistema de amamantamiento restringido. El análisis de los resultados se hizo mediante un dise o completamente al azar, con tres tratamientos y dos repeticiones por tratamiento; la unidad experimental la constituyeron cinco terneras. La calidad nutricional de las hojas de morera fué alta con 85.6% de degradabilidad de la materia seca a las 48 horas, 15.8% de proteína cruda, rendimiento de 52 t/ha/a o con cuatro cortes por a o y costos de $137.1 kg M.S., los incrementos de peso promedio fueron de 0.406, 0.437, 0.406 kg/día; con consumos de concentrado de 0.372, 0.207 y 0.115 kg/día para T1, T2, T3, respectivamente, encontrándose diferencias (P < 0.05) en consumos de concentrado. El consumo de hojas fué para T2 de 0.307 y T3 de 0.299 kg/día. El análisis económico, realizado por la técnica de presupuestos parciales, indicó ingresos netos de $190.864/animal para T2 seguidos por T3 ($185.027) y T1 $178.199).
Effect of Nicotine on Dopamine and Glutathione Levels in Presence of Oligoelements in Brain Regions of Young Rats——Effect of Nicotine on Brain Regions of Rat  [PDF]
David Calderón Guzmán, Ernestina Hernández García, Francisca Trujillo Jiménez, Gerardo Barragán Mejía, Hugo Juárez Olguín, José A. Saldivar González, Daniel Santamaria del Angel, Norma Osnaya Brizuela
Neuroscience & Medicine (NM) , 2012, DOI: 10.4236/nm.2012.33032
Abstract: Aim: The purpose of this study was to understand the mechanism of nicotine mediated addiction and the role of oligoelements in reducing its effect. Methods: Male Wistar rats (weight 80 g) were treated with single and repeated doses of nicotine and/or oligoelements as follows: group 1 (control) NaCl 0.9%; group 2, nicotine (1 mg/kg); group 3, oligoelements (50 μl/rat); and group 4, nicotine (1 mg/kg) + oligoelements (50 μl/rat). All drugs were intraperitoneally administered for 4 days. Blood for the measurement of glucose was obtained from all the animals. Samples of the brain regions (cortex, hemispheres and cerebellum + medulla oblongata) of each rat were obtained and used to measure the concentrations of dopamine, GSH levels, and lipid peroxidation (TBARS) using fluorescence and spectrophotometric methods. Results: Glucose level increased in rats treated with nicotine and oligoelements (p < 0.05), while GSH level decreased in cerebellum/medulla oblongata and hemispheres (p < 0.05) of the same animals. TBARS levels increased in cerebellum/medulla oblongata and hemispheres of animals treated with nicotine and oligoelements, but decreased in the same regions (p < 0.05) in rats treated only with oligoelements. The levels of dopamine decreased in cortex and hemispheres, but increased in cerebellum/medulla and oblongata regions of rats treated with both compounds (p < 0.05). Conclusions: Nicotine and oligoelements are associated with increase in the level of glucose, an effect that was more pronounced in the group treated with both drugs. Reduction of oxidative stress and dopamine metabolism may be involved in this effect.
Implementation of the Hough Transform for Iris Detection and Segmentation  [PDF]
Francisco Javier Paulín-Martínez, Alberto Lara-Guevara, Rosa María Romero-González, Hugo Jiménez-Hernández
Advances in Molecular Imaging (AMI) , 2019, DOI: 10.4236/ami.2019.91002
Abstract: The iris is used as a reference for the study of unique biometric marks in people. The analysis of how to extract the iris characteristic information represents a fundamental challenge in image analysis, due to the implications it presents: detection of relevant information, data coding schemes, etc. For this reason, in the search for extraction of useful and characteristic information, approximations have been proposed for its analysis. In this article, it is presented a scheme to extract the relevant information based on the Hough transform. This transform helps to find primitive geometries in the irises, which are used to characterize each one of these. The results of the implementation of the algorithm of the Hough transform applied to the location and segmentation of the iris by means of its circumference are presented in the paper. Two public databases of iris images were used: UBIRIS V2 and CASIA-IrisV4, which were acquired under the same conditions and controlled environments. In the pre-processing stage the edges are found from the noise elimination in the image through the Canny detector. Subsequently, to the images of the detected edges, the Hough transform is applied to the disposition of the geometries detected.
Diversidad genética en cerdos criollos mexicanos con genes candidatos asociados a características productivas
Sarabia, Alejandro Antonio González;Flores, Clemente Lemus;Martínez, Karina Mejía;Carpena, Javier Germán Rodríguez;Benítez, Maria Guadalupe Orozco;Serrano, Alberto Barreras;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011000100006
Abstract: the aim of this study was to compare the genetic variability and diversity, and genetic distances between mexican creole pigs - pelón mexicano (cpm) and cuinos (cc) - with the commercial breed yorkshire for the candidate genes cast, decr1, hal, hfabp4, lep, lipe, mcr4, myog, rn and chx, using the pcr-rflp technique. one hundred eighty pigs (59 cpm, 65 cc and 56 yorkshire) were evaluated. gene and genotypic frequencies, heterozygosity, genetic distances and filogenetic trees between breed groups were analyzed. in the comparison among the three breeds, the allelic and genotypic frequencies were different for cast, decr1, hfabp4, lep, mcr4 and chx. for lipe, cc pigs were similar to yorkshire; while for myog, the cpm were similar to yorkshire breeds. there were no differences in the genic and genotypic frequencies for hal and rn genes between creole and yorkshire populations. the yorkshire breed had higher favorable allele frequency for cast, lipe, mcr4 and myog, smaller for decr1, hfabp4, and for chx, and moderate for lep genes. the heterozygosity average for all genes was higher in cpm (0.42±0.05) and similar in both the cc (0.33±0.06) and yorkshire (0.35±0.05) breeds. in the estimation of genetic distances considering all genes, the cc breed are more distant from the yorshire pigs.
Detección de anticuerpos circulantes en donantes de sangre en México
Serrano Machuca,José J.; Villarreal Ríos,Enrique; Galicia Rodríguez,Liliana; Vargas Daza,Emma R.; Martínez González,Lidia; Mejía Damián,Alberto F.;
Revista Panamericana de Salud Pública , 2009, DOI: 10.1590/S1020-49892009001000011
Abstract: objective: to detect antibodies to six potentially blood-borne infections in blood donors at a social security institute in querétaro, mexico. methods: a cross-sectional, retrospective, descriptive study was performed using data from the blood bank records of the general regional hospital no. 1, mexican social security institute (imss). from the 6 929 registered donors, those with any antibody to brucellosis, chagas' disease, hepatitis b, hepatitis c, syphilis, and hiv were identified. for the cases presenting any of these infections, the following demographics were analyzed: age, gender, marital status, education, home address, and number of donations made. to estimate overall prevalence, the number of donors with any of the antibodies was divided by the total donors, and then by each of the various infections. results: of the 6 929 donors, 144 were detected with some type of circulating antibody of the six potentially blood-borne infections, with a total prevalence of 2.07% (0-4.4). the prevalence of blood donors with antibodies for hepatitis c was 0.721% (95%ci: 0.522-0.920) and chagas' disease, 0.649% (95%ci: 0.460-0.838). conclusions: identifying the prevalence of blood donors with antibodies for any of these six, potentially blood-borne infections, allows the blood bank at the general regional hospital no. 1 to establish its own epidemiologic profiling. chagas' disease proved to be emergent, calling for urgent control efforts.
Confiabilidad y validez de la escala de depresión CES-D en un censo de estudiantes de nivel medio superior y superior, en la Ciudad de México
González-Forteza, Catalina;Solís Torres, Cuauhtemoc;Jiménez Tapia, Alberto;Hernández Fernández, Itzel;González-González, Alejandro;Juárez García, Francisco;Medina-Mora, María Elena;Fernández-Várela Mejía, Héctor;
Salud mental , 2011,
Abstract: introduction depression and its symptoms are becoming one of the most important health problems worldwide. the impact of depression on the productive life of people, and the burden it represents because of its co-morbidity, is growing. some authors estimate that depression is the second cause for the global loss of years of healthy life and the first one in developed countries. an increasing proportion of teenage population has mental health issues. depression and its symptoms are among the most common, but they are not an epidemic problem yet, although spread enough as to maintain interest in its current impact and in its negative consequences over individual health. depression has a prominent place among mood disorders in mexico (4.5%), and women are who mostly suffer it (5.8%), which has remained consistent over time. different difficult situations occur during adolescence along with depression, depressive mood, and depressive symptoms. this situation may be related to changes and processes that occur during this period when individuals cope with situations they cannot handle, which in turn become stressful. therefore, it is necessary to study and to work with adolescents in order to be able to differentiate affective, cognitive, somatic, and behavioral expressions, which are proper to this stage, from those possibly caused by an illness that could have negative consequences. adolescent depression influences mood and the way individuals live unpleasant or annoying experiences, thus it affects almost every aspect of life and becomes a risk factor for psychiatric and behavioral problems. however, there are some areas that need more research, for example: the specific characteristics and expressions of the problem including gender comparisons and using designs with special groups. data show that depression is growing in adolescents; therefore it is a priority to work on detection and prevention to reduce its impact on mental health and to develop cost-effective inte
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