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Search Results: 1 - 10 of 70802 matches for " José ángel;Mares Arreola "
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Estudio florístico de los pi?onares de Pinus pinceana Gordon
Villarreal Quintanilla, José ángel;Mares Arreola, Oscar;Cornejo Oviedo, Eladio;Capó Arteaga, Miguel A.;
Acta botánica mexicana , 2009,
Abstract: a floristic study of 14 communities with pinus pinceana gordon was carried out. this species is distributed in small populations along the sierra madre oriental in northern and central mexico. a floristic similarity analysis between localities is included. a total of 446 species (plus 4 infaespecific taxa), 247 genera and 78 families were found. the communities can be separated by its flora into two groups: the northern one, located in coahuila, zacatecas and san luis potosí, and the southern one located in querétaro and hidalgo.
ESTUDIO FLORíSTICO DE LOS PI ONARES DE PINUS PINCEANA GORDON
José ángel Villarreal Quintanilla,Oscar Mares Arreola,Eladio Cornejo Oviedo,Miguel A. Capó Arteaga
Acta botánica mexicana , 2009,
Abstract: Se presenta un estudio de la flora de 14 comunidades con Pinus pinceana Gordon. Esta especie forma peque os bosques aislados a lo largo de la Sierra Madre Oriental, en el norte y centro de México. Se realizó un análisis de similitud florística entre las localidades estudiadas. Se reportan 446 especies, más 4 taxa infraespecíficas adicionales, distribuidas en 247 géneros y 78 familias. De acuerdo con su composición florística, las comunidades estudiadas se pueden separar en dos conjuntos: las más norte as, localizadas en Coahuila, Zacatecas y San Luis Potosí, y las de la región sur en Querétaro e Hidalgo. Se concluye que existen dos grupos de pi onares de P. pinceana, con base en sus diferencias florísticas y de distribución.
Simulation as a Support for Ultrasonic Testing  [PDF]
Pavel Mares
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.513118
Abstract:

Ultrasonic testing is a very important non-destructive method for testing components for safety of nuclear power plants and other security and delicate parts in other industries. Nowadays, thanks to the development of computer technology, it is possible to simulate processes which occur during ultrasonic testing. That is why numerical simulations are becoming an integral part of non-destructive testing. Simulations are used to determine parameters of ultrasonic examination, especially parameters of probes and scan plan and also in the analysis of results. They are used in such cases, when it is necessary to verify applicability of probes and methods. This verification could be provided on the weld and test block which are not manufactured. It could be also provided on defects, which are not manufactured in test block, but their presence is possible in given weld joint. Simulations are very useful for verifying the propagation of ultrasonic signal in given area (e.g. weld area). If movement of probe is limited, possibility of whole volume scan should be verified.

Análisis espectral del viento y de partículas menores de 10 micrómetros (PM10) en el área metropolitana de Monterrey, México
José Luis Arreola Contreras,Graciela González
Revista internacional de contaminación ambiental , 1999,
Abstract:
Estimating Stochastic Production Frontiers: A One-stage Multivariate Semi-Nonparametric Bayesian Concave Regression Method
José Luis Preciado Arreola,Andrew L. Johnson
Statistics , 2015,
Abstract: This paper describes a method to estimate a production frontier that satisfies the axioms of monotonicity and concavity in a non-parametric Bayesian setting. An inefficiency term that allows for significant departure from prior distributional assumptions is jointly estimated in a single stage with parametric prior assumptions. We introduce heteroscedasticity into the inefficiency terms by local hyperplane-specific shrinkage hyperparameters and impose monotonicity using bound-constrained local nonlinear regression. Our minimum-of-hyperplanes estimator imposes concavity. Our Monte Carlo simulation experiments demonstrate that the frontier and efficiency estimations are competitive, economically sound, and allow for the analysis of larger datasets than existing nonparametric methods. We validate the proposed method using data from 2007-2010 for Japan's concrete industry. The results show that the efficiency levels remain relatively high over the time period.
The Possible Utopia: A Gift of Hope and Reason for Action—Changing the Course of History!  [PDF]
Patricia Rodiles, José ángel Chevalier
Open Journal of Leadership (OJL) , 2015, DOI: 10.4236/ojl.2015.42005
Abstract: Today, the world’s current state reflects how we are living in a critical and chaotic time which brings multiple and challenging problems in social, economic, ecological and cultural aspects among many others. However, for women and men of good will, who yearn for a better, more human, and more solidary world, it is very encouraging that, despite this sad reality, there is a “possible utopia” that would change the course of history. But everybody asks themselves: How can we face a challenge of this magnitude? What path should we follow? Will man be able to change his mind and heart to do so? Will man have the faith, spirit and strength required? Will humanity be able to transform its creations of death into structures of life? What story should be built from now on to the future? It is an enormous and extremely complex task to have a better world, but if we are not willing to start, here and now, where and when will it be? And if we do not, who will? In this sense, Einstein and Edmund Burke challenge us as humanity, with their great motivating and appropriate statements: “If you want different results, do not do always the same” (as cited in Davidovich, Nikolay, Laugerman, & Commodore, 2010: p. 23) and “For evil to triumph [on earth] it is enough that good men do nothing” (as cited in Bartlett, 1968: p. 454; Kirk, 2009: p. 204; Landau, 2006: p. 222). Now, more than ever, it is the best time to start. Without a doubt, it is a monumental challenge, but also a “unique opportunity” that demands the availability of men and women, bold and brave, in order to unite their wills, to make possible the impossible, because our future as humanity is truly at stake.
índice de sitio para Pinus montezumae Lamb. en la región de cd. Hidalgo, Michoacán
Eladio Heriberto Cornejo Oviedo,Jordu00E1n Alejandro Pereyra Goicochea,Oscar Mares Arreola,Salvador Valencia Manzo
Revista fitotecnia mexicana , 2005,
Abstract: El objetivo del presente estudio fue comparar los métodos de la curva guía y estimación del parámetro al determinar el índice de sitio para P. montezumae en la región de Cd. Hidalgo, Mich. Se utilizó regresión no lineal para ajustar 634 pares de valores altura-edad procedentes de análisis troncal de 40 árboles dominantes. Con el método de la curva guía se probaron cinco modelos de crecimiento; y el de Gompertz fue el mejor porque presentó el valor más bajo del cuadrado medio del error (CME=11.145) y el valor más alto del coeficiente de determinación (R2=0.973); con dicho modelo se generaron cinco curvas de índice de sitio con interceptos diferentes, pero con pendiente constante que conforman curvas anamórficas. Con el método de la estimación del parámetro se usó el modelo de Chapman-Richards que presentó buen ajuste, dado su bajo valor del CME (10.186) y alto valor de R2 (0.976). Con dicho modelo se obtuvieron cinco curvas de índice de sitio con interceptos comúnes, con asíntotas que se incrementan con los índices de sitio y con una estimación de cero en la altura a una edad cero, que configuran curvas polimórficas. Los índices de sitio determinados con el método de la predicción del parámetro cubrieron con mayor confiabilidad y fidelidad la distribución de P. montezumae que con el método de la curva guía. En consecuencia, los índices de sitios determinados con el método de la predicción del parámetro deben usarse para la clasificación de la productividad en los bosques de P. montezumae en la región de Cd. Hidalgo, Mich.
índice de sitio para Pinus herrerae Martínez en Cd. Hidalgo, Michoacán
Oscar Mares Arreola,Eladio Heriberto Cornejo Oviedo,Salvador Valencia Manzo,Celestino Flores Lu00F3pez
Revista fitotecnia mexicana , 2004,
Abstract: El objetivo del presente estudio fue determinar el índice de sitio para Pinus herrerae Martínez en la Región de Cd. Hidalgo, Michoacán, a través de análisis troncales de 34 árboles dominantes. Para determinar el índice de sitio se utilizó el método de la curva guía, probando los modelos de crecimiento de Chapman-Richards, Gompertz, Logístico y Schumacher. El mejor modelo fue el de Chapman- Richards, ya que presentó el valor más bajo de CME=7.4891 y el valor más alto de R2=0.9845; además, los residuales estudentizados presentaron una distribución uniforme.
Estructura de tallas y crecimiento de los cangrejos Callinectes arcuatus y C. bellicosus (Decapoda: Portunidae) en la laguna costera Las Guásimas, México
Hernández,Luis; Arreola-Lizárraga,José Alfredo;
Revista de Biología Tropical , 2007,
Abstract: size frequency distribution and growth of the crabs callinectes arcuatus and c. bellicosus (decapoda: portunidae) in las guásimas coastal lagoon, mexico. information on size frequency distribution, the width-weight relation and growth parameters of the crabs callinectes arcuatus and c. bellicosus is presented. the data comes from samples taken with a trawl net both day and night on a monthly basis from march 1998 to february 2000 in a coastal lagoon from gulf of california. c. bellicosus (n= 878) was more abundant than c. arcuatus (n= 357) and its size frequency distribution presented carapace width cw ranges of 8.4-166 mm and 9-130 mm respectively. both populations were mainly represented by juveniles (75 mm in cw) ranging from 37 to 75 mm in cw, and adults (>75 mm in cw) between 76 and 90 mm in cw. in both species the widthweight relation showed that males grow more than females, with an isometric growth tendency being observed. the growth parameters for c. arcuatus estimated using the von bertalanffy model, were: k= 0.84 year-1, l∞= 140 mm to = -0.12 for c. arcuatus, and k= 0.9 year -1, l∞= 169 mm to = -0.11 for c. bellicosus. these results showed that the relative age at which maximum growth is attained is between three and four years for both species. rev. biol. trop. 55 (1): 225-233. epub 2007 march. 31.
Estructura de tallas y crecimiento de los cangrejos Callinectes arcuatus y C. bellicosus (Decapoda: Portunidae) en la laguna costera Las Guásimas, México
Luis Hernández,José Alfredo Arreola-Lizárraga
Revista de Biología Tropical , 2007,
Abstract: Presentamos información sobre la estructura de tallas, la relación ancho-peso y los parámetros de crecimiento de las jaibas Callinectes arcuatus y C. bellicosus. Las muestras fueron recolectadas mensualmente con una red de arrastre tipo camaronera durante el día y la noche desde marzo 1998 hasta febrero 2000 en una laguna costera del Golfo de California. C. bellicosus (n= 878) fue más abundante que C. arcuatus (n= 357) y su intervalo de talla de 8.4- 166 mm ancho del caparazón (AC) y 9-130 mm AC, respectivamente. Ambas poblaciones son representadas principalmente por jóvenes (75 mm AC) entre 37-75 mm AC y adultos entre 76- 90 mm AC. La relación ancho-peso mostró que los machos crecen más que las hembras en ambas especies y se observó una tendencia de crecimiento isométrico. Los parámetros de crecimiento para C. arcuatus estimados con el modelo von Bertalanffy fueron: K= 0.84 a o-1, L∞= 140 a -0.12 mm para C. arcuatus, y K= 0.9 a o -1, L∞= 169 a -0.11 mm para C. bellicosus. Estos resultados mostraron que la edad relativa a la cual se alcanza el crecimiento máximo es entre los tres y cuatro a os de edad para ambas especies. Size frequency distribution and growth of the crabs Callinectes arcuatus and C. bellicosus (Decapoda: Portunidae) in Las Guásimas coastal lagoon, Mexico. Information on size frequency distribution, the width-weight relation and growth parameters of the crabs Callinectes arcuatus and C. bellicosus is presented. The data comes from samples taken with a trawl net both day and night on a monthly basis from March 1998 to February 2000 in a coastal lagoon from Gulf of California. C. bellicosus (n= 878) was more abundant than C. arcuatus (n= 357) and its size frequency distribution presented carapace width CW ranges of 8.4-166 mm and 9-130 mm respectively. Both populations were mainly represented by juveniles (75 mm in CW) ranging from 37 to 75 mm in CW, and adults (>75 mm in CW) between 76 and 90 mm in CW. In both species the widthweight relation showed that males grow more than females, with an isometric growth tendency being observed. The growth parameters for C. arcuatus estimated using the von Bertalanffy Model, were: K= 0.84 year-1, L∞= 140 mm to = -0.12 for C. arcuatus, and K= 0.9 year -1, L∞= 169 mm to = -0.11 for C. bellicosus. These results showed that the relative age at which maximum growth is attained is between three and four years for both species. Rev. Biol. Trop. 55 (1): 225-233. Epub 2007 March. 31.
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