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Search Results: 1 - 10 of 533177 matches for " C. De León "
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Los reales de minas de la caja de Guadalajara durante el siglo XVIII: Circuitos comerciales y producción de plata
de León Meza, C. René
Revista de Indias , 2011,
Abstract: This article shows the economic significance of the group of mines that belonged to the jurisdiction of the Caja de Guadalajara . The novelty lies in that local historiography had erroneously labeled these mining camps as being small. Recent studies show that they were not so small after all. These groups of mines were the focal point of the economy of a vast region and triggered the development of agriculture, livestock and trade activities. This article reveals the nexus between the fluctuations in silver production and events in Europe. Este artículo da a conocer la importancia económica que tuvo un conjunto de reales de minas que perteneció a la jurisdicción de la caja de Guadalajara. Es novedoso porque por primera vez son estudiados aquéllos que la historiografía local ha considerado erróneamente como peque os reales de minas . Estas explotaciones fueron el eje articulador de la economía en una vasta región que impulsó el desarrollo de la ganadería, agricultura y comercio. Vincula las fluctuaciones en la producción de plata con sucesos ocurridos en Europa.
The corrosion behaviour of nanograined metals and alloys
Herrasti, P.,Ponce de León, C.,Walsh, F. C.
Revista de Metalurgia , 2012,
Abstract: There has been considerable interest in the properties of nanocrystalline materials over the last decade. Such materials include metals and alloys with a crystal size within the order of 1 to 100 nm. The interest arises due to the substantial differences in electrical, optical and magnetic properties and also due to their high adsorption capability and chemical reactivity compared to their larger grained counterparts. In this paper, the corrosion of nanocrystalline metals and alloys is investigated and compared to the corrosion of microcrystalline materials having a similar composition. The focus is on the corrosion of nickel, copper, cobalt and iron alloys. Key aspects of different corrosion behaviour such grain boundaries and size are identified. En la última década ha habido un gran interes en las propiedades de materiales nanocristalinos. Estos materiales incluyen metales y aleaciones con un tama o de cristal del orden de 1 a 100 nm. El interes por estos materiales es debido a las grandes diferencias en cuanto a sus propiedades electricas, opticas y magneticas, asi como a su alta capacidad de adsorción y reactividad química en relación a los mismos materiales con tama os de grano mayores. En este trabajo se ha investigado y comparado la corrosión de materiales nano y microcristalinos de similar composición química. Principalmente se ha centrado en la corrosión de metales tales como niquel, cobre, cobalto y aleaciones de hierro. Se ha comprobado que los diferentes comportamientos frente al proceso de corrosión están intimamente ligados con los bordes de grano y el tama o de dichos granos.
Spatial mosaic evolution of snail defensive traits
Steven G Johnson, C Darrin Hulsey, Francisco de León
BMC Evolutionary Biology , 2007, DOI: 10.1186/1471-2148-7-50
Abstract: Using spatial autocorrelation to account for genetic and geographic divergence among populations, we found no autocorrelation among populations at small geographic and genetic distances for the two defensive traits. There was also no correlation between abiotic variables (temperature and conductivity) and snail defensive traits. However, crushing resistance and frequency of pigmented shells were negatively correlated with molariform frequency. Crushing resistance and levels of pigmentation were significantly higher in habitats dominated by aquatic macrophytes, and both traits are phenotypically correlated.Crushing resistance and pigmentation of M. churinceanus exhibit striking variation at small spatial scales often associated with differences in primary productivity, substrate coloration and the frequency of molariform cichlids. These local geographic differences may result from among-habitat variation in how resource productivity interacts to promote escalation in prey defenses.Spatial variation in defensive traits is common in many antagonistic interactions [1-3]. The geographic mosaic theory of coevolution suggests that variation in ecological factors may underlie this patchiness in the phenotypic outcome of interactions, resulting in cold and hotspots of coevolution [2,4,5]. Despite evidence for coevolutionary cold and hotspots, very little evidence exists on how ecological conditions may enhance or constrain coevolution between antagonists. One current model suggests that coevolution might be related to gradients in resource productivity [6], with hotspots of coevolutionary selection associated with areas of high prey abundance. In specialist predator-prey interactions, predators have the greatest influence on prey phenotypes in geographic areas where the prey is most abundant whereas the predator exerts weaker selection in areas where prey are less abundant. Conditions of high prey abundance can occur when the abiotic environment is most favorable for prey me
Analisis del factor de valor presente de los costos esperados de da o por huracán en plataformas marinas
César E. Ortega Estrada,David de León Escobedo
Ciencia Ergo Sum , 2003,
Abstract: Se realiza un estudio de bondad de ajuste para obtener la distribución teórica que mejor representa a los valores observados referentes a los tiempos de arribo tanto de huracanes, como de tormentas de invierno. Se presenta la formulación para estimar el valor esperado de los costos asociados a la falla debidos a huracanes en las plataformas de la sonda de Campeche y se realiza un análisis cuantitativo de la influencia de cada uno de los parámetros de dicho factor.
Hamilton-Jacobi theory in Cauchy data space
Cédirc M. Campos,Manuel de León,David Martín de Diego,Miguel Vaquero
Physics , 2014,
Abstract: Recently, M. de Le\'on el al. ([9]) have developed a geometric Hamilton-Jacobi theory for Classical Field Theories in the setting of multisymplectic geometry. Our purpose in the current paper is to establish the corresponding Hamilton-Jacobi theory in the Cauchy data space, and relate both approaches.
Proximal esophageal ph-monitoring pH metría en esófago proximal
J. Pérez de la Serna,A. Ruiz de León San Juan,C. Sevilla Mantilla
Revista Espa?ola de Enfermedades Digestivas , 2010,
Abstract:
Laparoscopic versus laparotomy approach to endometrial cancer: A prospective study  [PDF]
López-De la Manzanara Carlos, Martín-Francisco Cástor, Luengo-Tabernero ángel, Garrido-Esteban Rosa Ana, León-Martín Alberto, Haya-Palazuelos Javier
Open Journal of Obstetrics and Gynecology (OJOG) , 2013, DOI: 10.4236/ojog.2013.34077
Abstract:

Objective: The aim of this study was to compare laparoscopic (LPS) and laparotomy (LPT) approaches for endometrial cancer, and to assess intraoperative and postoperative results, disease-free survival and overall survival. Methods: We designed a prospective observational study, every patient diagnosed of endometrial cancer and subsidiary to surgical staging was included. Total hysterectomy, bilateral adnexectomy, pelvic lymphadenectomy were performed in every case. Paraaortic lymphadenectomy was performed depending on tumor histology. Results: 70 patients with endometrial cancer were enrolled, 49 (70%) were treated laparoscopically and 21 (30%) laparotomically. There was not statistical significant difference in the mean operative time, it was 183.06 ± 21.03 min (range 120 - 230) in the LPS group and 195.24 ± 28.39 min (range 130 - 240) in the LPT group, mean difference 12.16 (95% CI 0.2 - 24). There was no difference in the number of lymph nodes resected. Mean blood loss was lower in the LPS group. There were less postoperative complications, 3 (6.12%) in the LPS group and 7 (33.3%) in the LPT group (p < 0.01). Mean hospital stay was significantly shorter in the LPS group 4.29 ± 1.62 days vs 8.81 ± 3.37 days in the LPT group (p < 0.01), mean difference 4.52 (95% CI 3.3 - 5.7). Overall survival was similar in both groups. Conclusion: Laparoscopic approach for endometrial cancer offers similar results in terms of survival and oncological radicality as the laparotomic approach and a lower rate of complications, a quicker convalescence time and a shorter hospital stay.

Hamilton-Jacobi Theory in k-Symplectic Field Theories
M. De León,D. Martín De Diego,J. C. Marrero,M. Salgado,S. Vilari?o
Physics , 2010, DOI: 10.1142/S0219887810004919
Abstract: In this paper we extend the geometric formalism of Hamilton-Jacobi theory for Mechanics to the case of classical field theories in the k-symplectic framework.
Elaboración de un yogurt con base en una mezcla de leche y garbanzo (Cicer arietinum)
Morales de León,Josefina C; Cassís Nosthas,Ma. Lorena; Cortés Penedo,Elizabeth;
Archivos Latinoamericanos de Nutrición , 2000,
Abstract: elaboration of yogurt made of milk and chickpea (cicer arietinum) mixture. the objective of ibis work was to establish the experimental conditions for the production of yogurt extended with chickpea (cicer arietinum), inoculated with st. thermophilus and l. bulgaricus and compare its chemical, microbiological and sensorial characteristics versus a yogurt made of skimmed milk. results indicated that 70:30 and 80:20 (skimmed milk and chickpea extract) mixtures obtained by chemical score fulfilled with the proposed objectives. yogurt made with 70:30 mixture added with modified starch (ul- tra sperce m and col-flo), did not remove syneresis present in these products and did not improve its sensory characteristics neither. nevertheless, yogurt made with 80:20 mixture and modified starch (ultra sperce m) removed syneresis and present flavor and texture characteristics alike yogurt made of milk, this "extended" yogurt was accepted by the 80% of the judge and fulfill with yogurt specification established in the mexican regulations for this products.
Inquérito epidemiológico sobre teníase em popula??o do programa saúde da família no município de Uberaba, MG
Esteves, Flavia Maria;Silva-Vergara, Mario León;Carvalho, ?ngela C.F. Banzatto de;
Revista da Sociedade Brasileira de Medicina Tropical , 2005, DOI: 10.1590/S0037-86822005000600017
Abstract: an epidemiologic survey was carried out on 110,144 people from the health family program to evaluate some epidemiologic aspects of teniasis. previous history of passing proglottides was registered in 185(0.2%) of them, and 112 (60.5%) received praziquantel. after this 97 (86.6%) passed proglottides characterized as taenia saginata and taenia solium in 36 (37.1%) and 4 (4.1%) respectively.
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