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Search Results: 1 - 10 of 12628 matches for " Sandra Grisell Mora Ravelo "
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Emisión de N2O con fertilización nitrogenada en fertirriego y fertilización convencional
Sandra Grisell Mora Ravelo,Manuel Sandoval Villa,Francisco Gavi Reyes,Prometeo Sánchez García
Revista internacional de contaminación ambiental , 2005,
Abstract: El relacionar el uso de fertilizantes químicos u orgánicos nitrogenados con la contaminación ambiental, implica adoptar alternativas que reduzcan las pérdidas de nitrógeno (N) del suelo que podría ser utilizado por los cultivos. La fertirrigación es una técnica de aplicación de agua y fertilizante que mejora la eficiencia en el uso de los fertilizantes mediante el riego por goteo. No existen reportes sobre como la fertirrigación afecta a la desnitrificación. El objetivo del presente trabajo es estudiar cómo afectan la fertirrigación y la fertilización convencional a la desnitrificación y verificar si, efectivamente, es posible reducir las emisiones de óxido nitroso (N 2 O) hacia la atmósfera. Se utilizó la captura de N 2 O in situpor el método adaptado por Grageda (1999) y Vivanco (2000). Las muestras de N 2 O se tomaron a las 2, 24, 48 y 72 h después del riego. La temperatura del suelo se midió con un termómetro aproximadamente a 10 cm de profundidad del suelo. La humedad del suelo (0 12 cm) se determinó con la ayuda de un instrumento DT DeltaT devices, tipo ML2 ThetaProbe. La cuantificación de N 2 O fue por cromatografía de gases. Los cálculos y análisis estadístico se efectuaron con el paquete estadístico SAS (SAS 1998). Los resultados obtenidos para la emisión de N 2 O manifiestan que el factor que más influyó en el sistema de riego convencional fue la humedad ya que existió una diferencia significativa a las 2, 24 y 48 h después del riego con respecto al fertirriego (riego por goteo). A pesar de que estadísticamente no hubo diferencia significativa en la emisión de N 2 O entre sistemas se obtuvo una concentración en riego por goteo de 0.69 y 2.82 mM menor que en el sistema convencional a las 48 y 72 h. Las temperaturas registradas a lo largo del desarrollo del cultivo estuvieron por debajo de las reportadas, por lo que se asume que este factor influyó en la disminución de la producción de N 2 O. Con respecto al pH del suelo se trabajó en un rango de 8.0 a 8.4, promedio superior al reportado como pH óptimo para el crecimiento de brócoli por lo que probablemente también influyó en la emisión de N 2 O en el sistema convencional y en el fertirriego.
Dinamic of Bacteria Desnitrificants and Nitrificants in the Rizospheric of Wheat with Slow Release of Fertilizer, Irrigated with Waste or Well Water  [PDF]
Sandra Grisell Mora-Ravelo, Francisco Gavi Reyes, Jesús Pérez Moreno, Juan José Pe?a Cabriales, Leonardo Tijerina Chávez, Ma. de Lourdes de la Isla de Bauer
Advances in Microbiology (AiM) , 2013, DOI: 10.4236/aim.2013.34048
Abstract:

The study of the paper about the rhizosphere in the transformation of nitrogen compounds can generate knowledge of the microbial and biochemical atmosphere of the rhizosphere of wheat, for the understanding of the dynamics of the N in agricultural zones, with the purpose of optimizing the fertilizer use and increasing the productivity of the cultures. Therefore, the objective of the present work was to know the effect the rhizosphere in the dynamics of the bacterial populations that take part in the cycle of the N in wheat nourished with slow release fertilizer and one commercial, irrigated with waste water or well. Analyses in the soil took place vertisol used in the experiment with the rhizospheric and non rhizospheric fraction. The slow release fertilizer used has a matrix enriched with N and P and is in the process of being patented (it explains in materials and methods). Each fertilizer was evaluated and the combination of the slow release fertilizer with organic fertilizer. The technique of the number most probable was used (MNP) to carry out the quantification of the nitrificants and denitrificants bacteria to the 55, 67 and 97 days after sowing (Dds). The results obtained for the MNP of denitrificants bacteria and Nitrosomonas indicate that the effect average of the types of water, soil and fertilizers, as well as their interaction to each other was not significant (p > 0.05). The effect of the fertilizing type and soil (rhizospheric and non rhizospheric) in the MNP of Nitrobacter was significant (p < 0.05). The tendencies show that the non rhizospheric soil is more favorable for the development of denitrificants bacteria and Nitrobacter, whereas the MNP of Nitrosomonas was greater in rhizospheric soil.

Desnitrificación de un fertilizante de lenta liberación y urea+fosfato monoamónico aplicados a trigo irrigado con agua residual o de pozo
Sandra Grisell Mora Ravelo,Francisco Gavi Reyes,Juan José Pe?a Cabriales,Jesús Peréz Moreno
Revista internacional de contaminación ambiental , 2007,
Abstract: El estudio de la emisión de óxido nitroso (N2O) producto de la combinación de tipos de fertilizante y agua en suelo rizosférico, y no rizosférico a lo largo del ciclo del cultivo, puede generar conocimiento que contribuya a incrementar la eficiencia de recuperación del N de los fertilizantes o abonos y a reducir las pérdidas de nitrógeno (N) por desnitrificación. El empleo eficiente de fertilizantes nitrogenados y de aguas residuales no tratadas de origen urbano por los cultivos es una necesidad agronómica, económica y ambiental. La desnitrificación es un factor importante que generalmente disminuye la eficiencia del N aplicado a los cultivos. El objetivo del presente trabajo fue evaluar la desnitrificación de un fertilizante de lenta liberación usando como referencia urea+fosfato monoamónico y fertilizante orgánico, en trigo irrigado con agua residual o de pozo. Se efectuaron análisis en el suelo vertisol empleado en el experimento con la fracción rizosférica y no rizosférica. El fertilizante de lenta liberación usado tiene una matriz enriquecida con N y fósforo (P) y se encuentra en proceso de ser patentado. Se evaluó cada fertilizante y la combinación del fertilizante de lenta liberación con fertilizante orgánico. Las muestras de suelo rizosférico y no rizosférico fueron colectadas a los 55, 67 y 97 días después de la siembra, se incubaron durante 18 días a una temperatura de 25 °C controlando diariamente la humedad. Los resultados (p < 0.05) arrojaron que las interacciones entre: muestreos y tipos de agua, muestreos y fertilizantes y tipos de agua y fertilizantes afectaron (p < 0.06) la emisión de N2O, la cual se incrementó al aplicar urea+fosfato monoamónico junto con agua residual. En promedio existió menos emisión de N2O al aplicar fertilizante de lenta liberación o fertilizante orgánico al irrigar con agua de pozo que con agua residual. El uso de agua residual en promedio se asoció con una mayor pérdida de N. La mayor emisión promedio de N2O ocurrió a los 67 días después de la siembra. La desnitrificación promedio fue similar en el suelo rizosférico y no rizosférico.
Desnitrificación de un fertilizante de lenta liberación y urea+fosfato monoamónico aplicados a trigo irrigado con agua residual o de pozo
MORA RAVELO, Sandra Grisell;GAVI REYES, Francisco;PE?A CABRIALES, Juan José;PERéZ MORENO, Jesús;TIJERINA CHáVEZ, Leonardo;VAQUERA HUERTA, Humberto;
Revista internacional de contaminación ambiental , 2007,
Abstract: the study of n2o emission originated by the combination of different types of fertilizers and water on rizospheric soil, and non- rizospheric soil along the crop cycle, can contribute to useful knowledge in order to increase fertilizer and manure n recovery efficiency and to reduce the n loss by denitrification. the efficient use of nitrogen fertilizers and non- treated urban waste water for crops is an agronomic, economic and environmental need. the denitrification is an important factor that diminishes the n efficiency in crops. the objective of this investigation was to evaluate the denitrification of a slow release fertilizer using as reference urea plus monoamonium phosphate and an organic fertilizer, applied to wheat irrigated with urban waste water or well water. analyses were made in the vertisol type soil used in the experiment with both, rizospheric and non-rizospheric soil. the slow release fertilizer used has a matrix enriched with n and p and its patent is currently in progress. each fertilizer was evaluated alone, as well as the slow release fertilizer plus organic fertilizer. the samples of rhizospheric and non-rhizospheric soils for each treatment were collected at 55, 67 and 97 days after sowing and incubated during 18 days at 25 °c, controlling the soil humidity daily. the results (p < 0.05) showed that the interactions between samplings and types of water, samplings and fertilizers, and types of water and fertilizers affected (p < 0.06) the emission of n2o, which was increased when urea plus monoamonium phosphate and waste water were applied. on average, there was less n2o when emissions slow release fertilizer or organic fertilizer were applied and irrigated with well water as compared to irrigation with waste water. as well, use of waste water was, on average, associated with a bigger loss of n. the highest average emission in n2o was observed 67 days after sowing. the average denitrification was similar in the rhizospheric and non-rhizospheric
Long Term Outcomes of Cross-Hatching Eustachian Tuboplasty  [PDF]
Carlos Yanez, Sandra Velázquez, Nallely Mora
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2015, DOI: 10.4236/ijohns.2015.41002
Abstract: Objective: To review the long term outcomes of cross-hatching Eustachian Tuboplasty (ChEt) in patients with chronic obstructive Eustachian tube dysfunction (COETD), as well as assess the clinical factors associated with surgical success. Study Design: Retrospective case series review. Setting: Tertiary healthcare institution. Methods: This is a retrospective review of non-revision ChET for COETD. Follow-up period was 5 years. The inclusion criteria were persistent otitis media with effusion, conductive hearing loss of 5 or more years, and constant COETD related-symptoms. The curvature of the posterior cushion was modified using an argon laser to alter the spring of the cartilage alleviating the obstructed valve’s aperture. Several clinical factors were reviewed in relation to the successful opening of Eustachian tube valve. Results: One hundred and twenty patients, 72 males/48 females, average age 42.4 + 2 years old, met study inclusion criteria. COETD patients/ obstructive causes were: Posterior cushion hypertrophy, 68 (56.6%); Tensor Veli and Levator Veli Palatini muscles hypertrophy, 15 (12.5%); Remarkable mucosal hypertrophic disease, 37 (30.8%). Total of ET tubes was 198. Bilateral 143 (72.2%), 55 unilateral (27.7%) ET valve was seen more open postoperatively on simple endoscopy (SE) and slow motion video analysis (SMVEA). There were no complications. Mean pure tone average improved by 20 dB postoperatively; P = 0.015. Mean immitance changes in tympanometric measurements improved postoperatively at least 0.10 mmhos in 91% of the patients (P = 0.010). Resolution of symptoms was considered a successful outcome. Failure correlated with the severity of disease. Conclusion: High rates of improvement (96%) were achieved. ChEt is a promising technique for the treatment of COETD
Aplicación de técnicas bayesianas en el análisis genético de árboles forestales
Mora,Freddy; Perret,Sandra;
Bosque (Valdivia) , 2007, DOI: 10.4067/S0717-92002007000300003
Abstract: this study was undertaken to investigate bayesian methods to scientific inference in forest tree breeding. the independence chain (ic) and gibbs sampling (gs) algorithms were applied on data sets from a field trial of eucalyptus cladocalyx aiming to predict random family and additive genetic effects, respectively. the trial was carried out in the coastal area of coquimbo region, northern chile. diameter and height growth rate (tcd and tca) were the data sets collected in a period of 30 months. bayesian procedures were compared with the ranking obtained by best linear unbiased prediction (blup). blup and ic had similar family ranking, although the family selection based on credible intervals of the genoty-pic effects (bayesian framework) was clearly more intensive. spearman rank correlation coefficients were high and significant (ps= 0.99) between blup and gs. the estimates of heritability were moderate: h2= 0.42 (tca) and h2= 0.43 (tcd). the traits had a significant correlation (ts= 0.7). the estimated genetic gains, in relation to the experimental average, ranged from 17% to 28%. the greatest genetic gain and genetic diversity of the original diversity of the experimental populations may be achieved and maintained if the trees are selected for tcd. it was conclude hat the bayesian inference may be a useful tool in the genetic evaluation of forest trees, since it incorporates the variability of the genetic parameters by using posterior distributions
Aplicación de técnicas bayesianas en el análisis genético de árboles forestales Applications of bayesian techniques in forest tree breeding
Freddy Mora,Sandra Perret
Bosque (Valdivia) , 2007,
Abstract: El objetivo de este estudio fue investigar los métodos bayesianos como una alternativa de inferencia científica aplicada a la evaluación genética forestal. Se usaron los algoritmos de Cadenas Independientes (IC) y de Gibbs (GS) en un conjunto de datos provenientes de un ensayo de Eucalyptus cladocalyx, para la predicción del efecto familiar e individual, respectivamente. El ensayo fue establecido en el sector costero de la Región de Coquimbo, norte de Chile. Se evaluó la tasa de crecimiento promedio de la altura (TCA) y el diámetro (TCD), medidas en un periodo de 30 meses. Los procedimientos se compararon con la mejor predicción linear inses-gada (BLUP). Se confirmó una significativa asociación entre el ranking familiar de BLUP e IC, aunque se evidenciaron mayores intensidades de selección al utilizar las regiones de credibilidad de los efectos genotípicos (enfoque bayesiano). Se obtuvieron altas y significativas correlaciones de Spearman (Ts= 0,9) entre BLUP y GS. Se obtuvieron moderadas heredabilidades individuales: h2=0,42 (TCA) y h2 = 0,43 (TCD). Las características se correlacionaron significativamente entre sí (Fs = 0,7). Las ganancias genéticas, en relación al promedio del ensayo, variaron de 17% a 28%. Al seleccionar para TCD, mayor ganancia y diversidad genética puede ser alcanzada y mantenida que la diversidad encontrada en este ensayo de progenie. Se concluyó que la inferencia bayesiana puede ser una herramienta metodológica útil en la evaluación genética forestal, ya que permitió incorporar la variación de los parámetros genéticos a través de las distribuciones a posteriori This study was undertaken to investigate bayesian methods to scientific inference in forest tree breeding. The Independence Chain (IC) and Gibbs sampling (GS) algorithms were applied on data sets from a field trial of Eucalyptus cladocalyx aiming to predict random family and additive genetic effects, respectively. The trial was carried out in the coastal area of Coquimbo Region, northern Chile. Diameter and height growth rate (TCD and TCA) were the data sets collected in a period of 30 months. Bayesian procedures were compared with the ranking obtained by Best Linear Unbiased Prediction (BLUP). BLUP and IC had similar family ranking, although the family selection based on credible intervals of the genoty-pic effects (bayesian framework) was clearly more intensive. Spearman rank correlation coefficients were high and significant (Ps= 0.99) between BLUP and GS. The estimates of heritability were moderate: h2= 0.42 (TCA) and h2= 0.43 (TCD). The traits had a significant corre
Nursing care to the patient with implantable automatic fibre-removing machine
Sandra Isabel García Mora
NURE Investigación , 2011,
Abstract: The primary prevention of the cardiac sudden death constitutes one of the main challenges of the present cardiology. The main reason for this interest comes dice by the little possibilities of surviving an extra-hospital cardiac shutdown, smaller of 20%.El implantable automatic fibre-removing machine (DAI) is the most effective therapy to prevent the cardiac sudden death related to ventricular tachyarrhythmias. From the beginnings of the therapy by means of the DAI, besides the survival and the quality of life of the patients it has constituted an important reason for attention. The carrying patients present/display agreements that can have an excellent impact in their quality of life. The infirmary personnel must know the therapy the DAI, to be able to provide to the patients and their familiar surroundings the optimal cares to confront its daily life, a level of confidence and comfort derived from the positioning of a permanent electronics.
METACOGNICION: UN CAMINO PARA APRENDER A APRENDER
Osses Bustingorry,Sonia; Jaramillo Mora,Sandra;
Estudios pedagógicos (Valdivia) , 2008, DOI: 10.4067/S0718-07052008000100011
Abstract: in this article metacognition is focused as a feasible alternative for training independent learners based on an education empowering consciousness on one's own cognitive pro-cesses and self-regulation of them, from the students' point of view. in such a way, it will lead them to learn how to learn, that is, to guide their learning and transfer it to other fields in their lives.
Una aproximación al uso de herramientas de gerencia estratégica de costos en instituciones privadas de educación superior
Cárdenas-Mora,Sandra Milena;
Cuadernos de Contabilidad , 2011,
Abstract: this paper presents the results of a study aimed to identify processes of strategic management of costs in decision making at private universities. as a framework we use three elements of the strategic management of costs and its importance as an engine of competitive advantage, and the analysis of the resultant information is structured around this notion. the results of this exploratory research reflect the limited use of cost information in the management processes of the studied institutions. from this, as an initial result of what may be an area of research on costs in service organizations, a proposal is made for the articulation of the strategic management variables in cost management processes of organizations of higher education.
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