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Rodriguez J.C.C.,Technological Institute of Oaxaca | Servia J.L.C.,National Polytechnic Institute of Mexico
Revista Fitotecnia Mexicana | Year: 2010

Tomato breeding programs generally manage a narrow genetic base, and thus it is necessary to explore and identify the natural genetic variation of this specie as a source of genes for improving productivity, improving adaptation, and solving pest and disease problems. To characterize the agromorphological variation of a collection of both wild and semidomesticated tomatoes (Lycopersicon esculentum var cerasiforme Dunal) from the state of Oaxaca, México, 49 populations were collected and characterized under greenhouse conditions. Significant differences among populations were detected in all evaluated traits except for days to fruiting on the fifth raceme. Principal component analysis showed that days after transplant to blossom initiation, fructification ripening, number of fruits on the fifth raceme, plant height at 30 d after transplant, fruits per raceme, and average fruit weight were the most important traits for describing morphological variability. Cluster analysis revealed the existence of two large groups, one for the wild and another for the semi-domesticated tomatoes. The first group consisted of four subgroups of variants with pear-shaped or rounded-flattened fruits with 3 to 5 locules, 2.5 to 3.7 cm in diameter and 2.6 to 3.1 cm in length. The second group joined populations with smaller fruits, indicating their wild condition, fruits with two locules, fruit diameter and length less than 2 cm, high production of flowers per raceme (5 to 7) and 20 to 30 fruits at the fifth raceme, precocity for fruiting at the fifth raceme (53 to 55 d after transplant) and indeterminate growth (1.3 to 1.7 m at 60 d after transplant). There is important variation in Oaxaca regarding phenological, plant, stem, leaf, flower and fruit traits in both wild and semi-domesticated populations of tomato. Source

Rojas-Zarate Y.,Technological Institute of Oaxaca | Mondragon D.,National Polytechnic Institute of Mexico
Revista Mexicana de Biodiversidad | Year: 2016

Although there are bromeliad inventories for Mexico, some regions of the country have not yet been extensively sampled, as is the case of the district of Zaachila in Oaxaca. According to the literature, there are only 3 species of epiphytic bromeliads there. However, large areas of pine-oak and oak suggest a greater richness of epiphytic bromeliads. In order to complement Mexican bromeliad records, specifically in the Oaxacan region, 2 plots (1 ha/plot) were sampled in the 3 vegetation types reported for the District of Zaachila: pine, pine-oak and oak. The objective was the search of bromeliad species present in each type of vegetation. We found 17 species of bromeliads: 16 belonging to genus Tillandsia and 1 to genus Catopsis. The pine-oak forest was the most diverse, with 16 species; followed by oak forest, with 7 species, and pine forest with 2 species. We are presenting the first formal inventory of epiphytic bromeliads of the Zaachila District. © 2016 Universidad Nacional Autónoma de México, Instituto de Biología. Source

Trejo F.,National Polytechnic Institute of Mexico | Rana M.S.,Kuwait Institute for Scientific Research | Ancheyta J.,Mexican Institute of Petroleum | Rueda A.,Mexican Institute of Petroleum | Rueda A.,Technological Institute of Oaxaca
Fuel | Year: 2012

Pure and mixed oxides (Al 2O 3, ZrO 2, Al 2O 3-MgO, Al 2O 3-SiO 2, Al 2O 3-TiO 2, and Al 2O 3-ZrO 2) were prepared by homogeneous delayed precipitation. The synthesized supports were impregnated by incipient wetness method to obtain CoMo catalysts. Both supports and catalysts were characterized by N 2 physisorption, X-ray diffraction, among other techniques. Acid-base properties were studied with isopropyl alcohol and cumene decomposition. It was possible to assess qualitatively that nature of Al-Si and its respective catalyst was mainly acidic. Conversion of isopropyl alcohol leads to the dehydration products, mostly propylene with a low amount of di-isopropyl ether and acetone. The CoMo/Al 2O 3-SiO 2 catalyst showed the highest conversion during cumene cracking. CoMo/Al 2O 3-SiO 2 catalyst also was the most active during thiophene hydrodesulfurization followed by CoMo/Al 2O 3-TiO 2 catalyst. © 2012 Elsevier Ltd. All rights reserved. Source

Flores-Ruiz F.J.,CINVESTAV | Enriquez-Flores C.I.,CINVESTAV | Chinas-Castillo F.,Technological Institute of Oaxaca | Espinoza-Beltran F.J.,CINVESTAV
Applied Surface Science | Year: 2014

Fullerene-like carbon nitride films exhibit high elastic modulus and low friction coefficient. In this study, thin CNx films were deposited on silicon substrate by DC magnetron sputtering and the tribological behavior at nanoscale was evaluated using an atomic force microscope. Results show that CNx films with fullerene-like structure have a friction coefficient (CoF ∼ 0.009-0.022) that is lower than amorphous CNx films (CoF ∼ 0.028-0.032). Analysis of specimens characterized by X-ray photoelectron spectroscopy shows that films with fullerene-like structure have a higher number of sp3 CN bonds and exhibit the best mechanical properties with high values of elastic modulus (E > 180 GPa) and hardness (H > 20 GPa). The elastic recovery determined on specimens with a fullerene-like CNx structure was of 95% while specimens of amorphous CNx structure had only 75% elastic recovery. © 2014 Elsevier B.V. Source

Alavez-Ramirez R.,The Interdisciplinary Center | Chinas-Castillo F.,Technological Institute of Oaxaca | Morales-Dominguez V.J.,The Interdisciplinary Center | Ortiz-Guzman M.,The Interdisciplinary Center
Construction and Building Materials | Year: 2012

This study evaluates the potential use of coconut fibre as thermal isolating filler for ferrocement panel walls in sandwich configuration of schools and houses' roofing in Puerto Escondido, Oaxaca, Mexico. Thermal conductivity measurements were performed to compare the thermal behaviour of ferrocement panel walls filled with coconut fibre to other typical building materials of the region. Measured thermal conductivities for red clay brick, hollow concrete block and lightweight concrete brick panel walls are 0.93, 0.683 and 0.536 W/m K respectively. Thermal conductivity of the proposed configuration is 0.221 W/m K and that is lower than typical materials used for home-buildings in this region. © 2012 Elsevier Ltd. All rights reserved. Source

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