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Search Results: 1 - 10 of 86034 matches for " Deysi Y. Cruz-González "
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Sulphated Zirconia as an Eco-Friendly Catalyst in Acylal Preparation under Solvent-Free Conditions, Acylal Deprotection Assisted by Microwaves, and the Synthesis of Anhydro-Dimers of o-Hydroxybenzaldehydes
Laura Nadxieli Palacios-Grijalva,Deysi Y. Cruz-González,Leticia Lomas-Romero,Eduardo González-Zamora,Gerardo Ulibarri,Guillermo E. Negrón-Silva
Molecules , 2009, DOI: 10.3390/molecules14104065
Abstract: A solvent-free approach is described for the regioselective synthesis of acylals (1,1-diacetates) in shorter reaction times and higher yields, compared to conventional methodology using solvents. In the protection reaction of the o-hydroxybenzaldehyde the formation of acetyl compounds and anhydro-dimers was observed. The deprotection reaction involves microwave (MW) exposure of diluted reactants in the presence of solid sulphated zirconia (SZ) catalyst that can be easily recovered and reused. The sulphated zirconia was recycled several times without any loss of activity.
IMF from infrared photometry of young stellar clusters in Taurus-Auriga and Orion
Salas, Luis;Cruz-González, Irene;
Revista mexicana de astronomía y astrofísica , 2010,
Abstract: we applied the extinction-disk-principal vectors approach to near infrared photometric data of the taurus-auriga region and orion nebula young stellar clusters. by assuming that the cluster age is represented by the median value of the age distribution we are able to derive the distribution of stellar masses. we showed that the resulting initial mass function (imf) for these two young stellar clusters compares remarkably well and might be a robust representation of the imf obtained by spectroscopic or photometric methods. the method also yields the extinction and disk contribution for each star. the overall extinction distribution for the orion cluster is analyzed and compares well with previous work. the frequency of t tauri stars with disks is about 50%.
H2 Velocity structure in the molecular outflow DR 211
Cruz-González, Irene;Salas, Luis;Hiriart, David;
Revista mexicana de astronomía y astrofísica , 2007,
Abstract: we describe the velocity structure of the molecular outflow dr 21 in the 2.12 μm line of h2. velocity cubes were obtained of the entire outflow emission using a scanning ir fabry-pérot interferometer with a spectral resolution of 24 km s-1. h2 emission was detected from both the dr 21 (e) and dr 21 (w) lobes in a velocity interval (-80.82, +46.84) km s-1. the most conspicuous sources found include a jet-like region and a possible counter-jet or an independent jet, an elliptical cavity and four bow-like structures. the velocity data cube was used to calculate the four velocity moment images of the outflow to study the moments along the outflow axis. turbulence in the outflow is studied via a clump find analysis. relations between clump parameters and kinematics allowed us to derive power-law relations in agreement with larson's laws.
Green Cycle: Sulfate Sorption from Natural Water on Anionic Clay Compound Obtained from Industry Wastewater  [PDF]
Genoveva Rosano-Ortega, Carlos Vega Lebrún, Juan M. López Oglesby, Sonia Martínez Gallegos, Daniel Cruz-González, Beatriz Pérez Armendariz
Green and Sustainable Chemistry (GSC) , 2013, DOI: 10.4236/gsc.2013.32009
Abstract: In this paper we are describing a green cycle process. The first step was a novel hydrotalcite-like compound (HTLC) synthesized by a co-precipitating method, under standard ambient temperature and pressure, using chemical industry wastewater rich in divalent and trivalent cations, activated by a thermal treatment and finally characterized by scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDS) and thermogravimetric analysis (TGA). The second step was a series of batch sorption tests performed with this activated HTLC and untreated underground sulfurous water from the state of Puebla, México. The HTLC calcined at 500°C/3 h exhibited the best sorption ability for ions, demonstrated a decrease of the hardness and sulfate ions to below the regional legal standards for drinking water. Once inactive after being used in water treatment, the sorbed ions were removed by ion exchange in a carbonate-containing solution, resulting in an 80% recycling of the material which upon activation demonstrated a retained capacity for water treatment. This recyclability suggests the exciting possibility of this novel compound as an efficient “green” technology in water treatment processes.
An estimate of the temporal fraction of cloud cover at San Pedro Mártir Observatory
E. Carrasco,A. Carrami?ana,L. J. Sánchez,R. Avila,I. Cruz-González
Physics , 2011, DOI: 10.1111/j.1365-2966.2011.20140.x
Abstract: San Pedro M\'artir in the Northwest of Mexico is the site of the Observatorio Astron\'omico Nacional. It was one of the five candidates sites for the Thirty Meter Telescope, whose site-testing team spent four years measuring the atmospheric properties on site with a very complete array of instrumentation. Using the public database created by this team, we apply a novel method to solar radiation data to estimate the daytime fraction of time when the sky is clear of clouds. We analyse the diurnal, seasonal and annual cycles of cloud cover. We find that 82.4 per cent of the time the sky is clear of clouds. Our results are consistent with those obtained by other authors, using different methods, adding support to this value and proving the potential of the applied method. The clear conditions at the site are particularly good showing that San Pedro M\'artir is an excellent site for optical and infrared observations.
Optical Spectroscopic ATLAS of the MOJAVE/2cm AGN Sample (1)
Janet Torrealba,Vahram Chavushyan,Irene Cruz-González,Tigran G. Arshakian,Emanuele Bertone,Daniel Rosa-González
Physics , 2011,
Abstract: We present an optical spectroscopic atlas at intermediate resolution (8-15A) for 123 core-dominated radio-loud active galactic nuclei with relativistic jets, drawn from the MOJAVE/2cm sample at 15GHz. It is the first time that spectroscopic and photometric parameters for a large sample of such type of AGN are presented. The atlas includes spectral parameters for the emission lines Hb, [O III] 5007, Mg II 2798 and/or C IV 1549 and corresponding data for the continuum, as well as the luminosities and equivalent widths of the Fe II UV/optical. It also contains the homogeneous photometric information in the B-band for 242 sources of the sample, with a distribution peak at BJ=18.0 and a magnitude interval of 11.1< BJ <23.7.
Recalibrated turbulence profiles at San Pedro Mártir
Avila, R.;Sánchez, L. J.;Cruz-González, I.;Carrasco, E.;Casta?o, V. M;
Revista mexicana de astronomía y astrofísica , 2011,
Abstract: the calibration of optical turbulence profiles measured with the generalized scidar technique has been recently reviewed and corrected by avila & cuevas (2009). based on that work, here we present the correction of all the profiles measured with a generalized scidar at the observatorio astronómico nacional of san pedro mártir. the median corrected profile conserves its overall vertical shape. the altitude-averaged ratio of the corrected median values over the uncorrected ones equals 0.87. the corrected median value of seeing at the site is 0.''68 ± 0."03, 4.2% lower than the median value obtained with the uncorrected profiles. the median values of the seeing produced by turbulence in the first 2 km above the 1.5 m and the 2.1 m telescopes decrease by 15.8% and 13.6%, respectively. the corrected isoplanatic angle has a median value of 1."96 ± 0."04.
Prevalencia de osteoporosis y ostopenia en mujeres tabasque as
Yrma del Cármen Bocanegra-Broca,Fernando Joaquín Cruz-Rubio,Carlos de la Cruz-González,Alejandro Jiménez-Sastré
Salud en Tabasco , 2006,
Abstract: Objetivo: Conocer la prevalencia de osteoporosis y osteopenia en mujeres tabasque as, usuarias del Hospital de la Mujer de la Secretaría de Salud de la ciudad de Villahermosa, Tabasco. Material y Método: Se realizó un estudio descriptivo, retrospectivo. Se incluyeron 894 pacientes a los que se les realizaron estudios de Densitometrías Mineral óseo con el equipo Lunar Prodigy Bone Densitometer System 8933ES durante los a os 2004- 2005. Análisis Estadístico: se utilizaron diversas medidas estadísticas: media, desviación estándar, tasa, razón, coeficiente de variación, curtosis y coeficiente de asimetría. Resultados: De los 894 diagnósticos densitométricos: 424 fueron normales, 286 con Osteopenia y 184 con Osteoporosis. Se obtuvo una prevalencia del 32% para osteopenia y del 20.6% para osteoporosis. La edad promedio de los pacientes con Osteopenia fue 56 ± 9.5 y con un rango de edad entre 35 a 85 a os. En lo que respecta a los pacientes con osteoporosis, La edad promedio fue de 62 ± 9.4, con un rango de edad entre 37 a 87 a os. Conclusión: La prevalencia obtenida en osteopenia es similar a otros reportes nacionales e internacionales, no así en la osteoporosis, que fue menor que en algunos otros países, y ligeramente por arriba de otros estudios mexicanos; hay que tomar en cuenta que el Hospital de la Mujer es de concentración y atiende a población abierta.
Análisis socioeconómico de la pesquería de calamar gigante en Guaymas, Sonora
Francisco Javier de la Cruz-González,Luis Felipe Beltrán-Morales,César Augusto Salinas-Zavala,Miguel ángel Cisneros-Mata
Economía, sociedad y territorio , 2011,
Abstract: En este trabajo hacemos un análisis socioeconómico de la pesquería de calamar gigante en Guaymas, Sonora. Se generó una base de datos con información pesquera y se aplicó una encuesta a pescadores y a trabajadores de la industria del calamar para determinar sus principales características socioeconómicas. Los resultados muestran que esta pesquería ha tenido una participación importante en la estructura productiva del sector pesquero de la región; sin embargo, el repunte en las capturas de calamar gigante en los últimos a os ha permitido el crecimiento de esta pesquería, pero no su desarrollo. El documento resalta la necesidad de orientar las políticas de manejo al aprovechamiento integral de este recurso.
Capital social, capital relacional e innovación tecnológica. Una aplicación al sector manufacturero espa ol de alta y media-alta tecnología
Miriam Delgado-Verde,Gregorio Martín-de-Castro,José Emilio Navas-López,Jorge Cruz-González
Cuadernos de Economía y Dirección de la Empresa , 2011,
Abstract:
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