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Search Results: 1 - 10 of 6463 matches for " Jaime;LONGORIA "
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Numerical simulation of 226Ra migration and decay in a saturated porous medium
DE LA CRUZ, Eduardo;GONZALEZ, Roberto;KLAPP, Jaime;LONGORIA, Luis Carlos;MAYORAL, Estela;DUARTE, Ricardo;
Revista internacional de contaminación ambiental , 2011,
Abstract: numerical simulation of transport and radioactive decay of 226ra as a constant product of 238u decay from a simulated storage facility containing uranium tailings is presented in this work. the simulation domain consists of six subsoil layers through which one of the uranium daughters 226ra is migrating as well as decaying. the methodology consists in first calculating the 226ra velocity field through the computational domain by solving the momentum and mass conservation equation using darcy′s law. the transport equation is then solved to obtain the extent of the contaminant′s migration. the solution is obtained with the finite-element method. results showed that the estimated 226ra migration time through 200 meters of soil was about five hundred years.
Numerical simulation of 226Ra migration and decay in a saturated porous medium
Eduardo DE LA CRUZ,Roberto GONZALEZ,Jaime KLAPP,Luis Carlos LONGORIA
Revista internacional de contaminación ambiental , 2011,
Abstract: En este trabajo se presenta una simulación numérica de la migración y del decaimiento de 226Ra como un producto constante del decaimiento del 238U a través del subsuelo de un almacén modelado que contiene jales de uranio. El dominio de simulación para modelar el transporte de 226Ra consiste en seis diferentes capas de tierra a través de las cuales los productos del 226Ra van migrando y decayendo. La metodología calcula el campo de velocidades por medio de la ecuación de momento y de conservación de masa usando la ley de Darcy. Posteriormente se utiliza este resultado para resolver la ecuación de transporte. La solución es obtenida con el método de elementos finitos. Los resultados muestran que el tiempo estimado de migración del 226Ra a lo largo de 200 metros de tierra fue de alrededor de 500 a os.
Trasnacionalidad y trasnacionalismo
Miguel MOCTEZUMA LONGORIA
Papeles de población , 2008,
Abstract: Este ensayo aborda el trasnacionalismo como una perspectiva de análisis que recoge y cuestiona enfoques teóricos, como el positivismo estructuralista y funcionalista materializado en los modelos asimilacionistas y aculturalistas de la migración. Surgido como un término en el campo de la economía política del siglo XIX para describir las corporaciones privadas que ya tenían grandes operaciones financieras y una presencia organizacional y administrativa en varios países, hoy en día se identifica al trasnacionalismo con la práctica de los migrantes, las redes de relación social y las comunidades filiales que se mueven más allá de las fronteras de los países. Aquí se postula que el trasnacionalismo y la trasnacionalidad requieren avanzar en su clasifi cación, acotar sus alcances y delimitar el papel que juegan éstos y otros fenómenos relacionados con la temática de la migración internacional.
Controllable Biosynthesis of Small Silver Nanoparticles Using Fungal Extract  [PDF]
Katrin Quester, Miguel Avalos-Borja, Ernestina Castro-Longoria
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2016, DOI: 10.4236/jbnb.2016.72013
Abstract: The search for reliable and eco-friendly methods for the production of nanoscale materials is an important aspect of nanotechnology. Silver nanoparticles (AgNPs) are of special interest because of their antimicrobial properties, especially those of small size. In this work, AgNPs were produced under different conditions of temperature and pH using the extract from the fungus Neurospora crassa as reducing agent. Mainly quasi-spherical particles were obtained at all incubation conditions. However, optimum conditions to produce small sizes in the range of 2 - 9 nm were at 4°C and pH 3, also particles of 2 - 22 nm were obtained at 25°C with unmodified pH (6.5) and pH 10. Nevertheless, only particles synthesized at 25°C and pH 10 maintained the same size range after storage of 10 months. In summary, optimal incubation conditions for the synthesis of silver nanoparticles of small size range are reported. This improves the storage time of particles without losing its original size and without going into aggregation or agglomeration.
Lower Cretaceous rocks of Sierra Los Chinos, east-central Sonora, Mexico
Rogelio Monreal,José F. Longoria
Geofísica internacional , 2000,
Abstract: Most Lower Cretaceous rocks in Sonora are part of the Bisbee Group of southern Arizona, deposited within a basin considered to be an extension of the Gulf of Mexico into Texas, New Mexico, Arizona and Sonora. However, the Lower Cretaceous rocks of the Sierra Los Chinos are more closely related to the Lampazos rocks of eastern Sonora, and consequently, to Chihuahua stratigraphy. In the Los Chinos area, the exposed Lower Cretaceous units include the Agua Salada, Lampazos and Los Picachos Formations. The Upper Cretaceous sequence is made up of volcanosedimentary rocks overlain by Tertiary intrusive, volcanic, and sedimentary rocks. Lower Cretaceous rocks of the Sierra Los Chinos area are strongly folded and faulted, with kilometer-scale overturned folds and thrusts. The area was affected by at least two episodes of normal faulting. The Sierra Los Chinos sequence is paleogeographically and tectonically related to the Chihuahua tectonic belt and is unrelated to the Bisbee Group of Sonora. The marine conglomerate at the base of the Los Picachos Formation represents a significant active tectonic episode at the end of the Albian, possibly related to re-activation of strike-slip faulting due to tectonic transpression. The compressional structures in the Los Chinos area are similar to structures of the same age in the states of Chihuahua, Coahuila, and Nuevo León.
Factores pronósticos anatomopatológicos de supervivencia en el cáncer de mama
González-Longoria Boada,Lourdes B;
MEDISAN , 2012,
Abstract: a descriptive and longitudinal study of 273 women with breast cancer belonging to granma province was carried out from 2003 to 2004, in order to analyze the survival of this female population, reason why the method of kaplan meier was used for the calculation of the mentioned variable and the log rank test was used for the comparison of curves. patients with higher survival at 5 years were those who had tumors of 2 cm or less (87.5%), histological grade i (90.3%), nuclear grade i (88.3%), as well as the absence of vascular, lymphatic or lymph node invasion (with 80.6; 74.9 and 6.1% respectively). also, tumor size, histological and nuclear grade, nodal status, as well as lymphatic and vascular invasion constituted prognosis factors, which favored the individualization of therapeutic behaviors.
La reorganización del territorio parroquial de la arquidiócesis de México durante la prelacía de Manuel Rubio y Salinas (1749-1765)
álvarez Icaza Longoria, María Teresa
Hispania Sacra : Revista de Historia Eclesiástica , 2011,
Abstract: Since 1750 Archbishop Manuel Rubio y Salinas ordered the taking place of the transference to clerics from doctrines previously administered by the regular clergy. Several of the secularized curates used to have a vast territory, the Diocesan prelate decided to divide them. As there were more parishes, a higher number of the clerics could have more chance to get accommodation. In addition, argued Rubio, the parishioners were favored because it improved their spiritual administration. The establishment of these boundaries was sometimes done with the consensus of several actors involved, but in other cases it involved conflicts that could represent a number of major obstacles in the process of creating new parishes. A partir de 1750 el arzobispo Manuel Rubio y Salinas ordenó que se llevara a cabo la transferencia a clérigos de doctrinas hasta entonces administradas por el clero regular. Varios de los curatos secularizados tenían un territorio muy amplio; el prelado diocesano tomó la decisión de dividirlos. Al existir más parroquias tenían ocasión de conseguir acomodo mayor número de clérigos; además, argumentaba Rubio, los feligreses se veían beneficiados porque mejoraba su administración espiritual. El establecimiento de estas demarcaciones a veces fue realizado con el consenso de los diversos actores involucrados, pero en otras implicó conflictos que pudieron representar obstáculos importantes en el proceso de creación de nuevas sedes parroquiales.
Factores pronósticos anatomopatológicos de supervivencia en el cáncer de mama Survival pathological prognosis factors in breast cancer
Lourdes B González-Longoria Boada
MEDISAN , 2012,
Abstract: Se efectuó un estudio descriptivo y longitudinal de 273 mujeres con cáncer de mama de la provincia de Granma, desde 2003 hasta 2004, a fin de analizar la supervivencia de esta población femenina, con vistas a lo cual se utilizó el método de Kaplan Meier para el cálculo de la citada variable y el test de Log Rank para la comparación de curvas. Las pacientes con mayor sobrevida a los 5 a os fueron las que tenían tumores de 2 cm o menos (87,5%), grado histológico I (90,3 %), grado nuclear I (88,3 %), así como no invasión vascular, linfática o ganglionar (con 80,6; 74,9 y 86,1 %, respectivamente). Además, el tama o tumoral, los grados histológico y nuclear, el estado ganglionar, así como la invasión linfática y vascular constituyeron factores pronósticos, lo cual favoreció la individualización de las conductas terapéuticas. A descriptive and longitudinal study of 273 women with breast cancer belonging to Granma province was carried out from 2003 to 2004, in order to analyze the survival of this female population, reason why the method of Kaplan Meier was used for the calculation of the mentioned variable and the Log Rank test was used for the comparison of curves. Patients with higher survival at 5 years were those who had tumors of 2 cm or less (87.5%), histological grade I (90.3%), nuclear grade I (88.3%), as well as the absence of vascular, lymphatic or lymph node invasion (with 80.6; 74.9 and 6.1% respectively). Also, tumor size, histological and nuclear grade, nodal status, as well as lymphatic and vascular invasion constituted prognosis factors, which favored the individualization of therapeutic behaviors.
Cargo Transport by Cytoplasmic Dynein Can Center Embryonic Centrosomes
Rafael A. Longoria, George T. Shubeita
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067710
Abstract: To complete meiosis II in animal cells, the male DNA material needs to meet the female DNA material contained in the female pronucleus at the egg center, but it is not known how the male pronucleus, deposited by the sperm at the periphery of the cell, finds the cell center in large eggs. Pronucleus centering is an active process that appears to involve microtubules and molecular motors. For small and medium-sized cells, the force required to move the centrosome can arise from either microtubule pushing on the cortex, or cortically-attached dynein pulling on microtubules. However, in large cells, such as the fertilized Xenopus laevis embryo, where microtubules are too long to support pushing forces or they do not reach all boundaries before centrosome centering begins, a different force generating mechanism must exist. Here, we present a centrosome positioning model in which the cytosolic drag experienced by cargoes hauled by cytoplasmic dynein on the sperm aster microtubules can move the centrosome towards the cell’s center. We find that small, fast cargoes (diameter ~100 nm, cargo velocity ~2 μm/s) are sufficient to move the centrosome in the geometry of the Xenopus laevis embryo within the experimentally observed length and time scales.
Data Mining of Historic Hydrogeological and Socioeconomic Data Bases of the Toluca Valley, Mexico  [PDF]
Oliver López-Corona, Oscar Escolero Fuentes, Eric Morales-Casique, Pablo Padilla Longoria, Tomás González Moran
Journal of Water Resource and Protection (JWARP) , 2016, DOI: 10.4236/jwarp.2016.84044
Abstract: In this paper we used several data mining techniques to analyze the coevolution of hydrogeological and socioeconomical data for the Toluca Valley in Mexico. We found non trivial relations between two historic data bases that make clear that groundwater and economy may be much more linked than it was thought before. In particular, we found that hydrogeological data trends change during economical crisis and election years in Mexico. This shows that different macroeconomical policies implemented by several administrations have a direct impact in the way groundwater is used. We also found that hydrogoelogical data evolve in the direction of population transformation from rural to urban, which could represent a whole paradigm shift in groundwater management with profound repercussions in policy making.
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