Time filter

Source Type

Fonseca-Gonzalez J.,Autonomous University of the State of Hidalgo | de los Santos-Posadas H.M.,Colegio de Mexico | Rodriguez-Ortega A.,Polytechnic University of Francisco I. timber | Rodriguez-Laguna R.,Autonomous University of the State of Hidalgo
Agrociencia | Year: 2014

Forest ecosystems are susceptible to wildfires, whose effects may vary greatly depending on their intensity and severity, causing changes in vegetation and biological activity. Infestation of bark beetles is one of the major consequences. The objective of this study was to analyze insect colonization and Pinus patula mortality following a forest fire in a regeneration area using logistic regression. Follow-up lasted 16 months at the municipality of Cuautepec de Hinojosa, state of Hidalgo, México. The variables assessed on trees were percentage of scorched crown, percentage of trunk circumference with evidence of entry of bark beetles of the genus Ips, number of pitch tubes caused by insects of the genus Dendroctonus, evidence of colonization by wood borers, and whether the tree was alive or dead. Of the insects that colonized trees killed by the fire, 99 % were secondary bark beetles: Ips integer, I. bonanseai, I. cribricollis, Pseudips mexicanus and Pityophthorus sp. One was an ambrosia beetle Gnathotrichus sp. In live trees after the forest fire, there was also evidence of attack by Dendroctonus valens and D. mexicanus. There was a strong relationship between fire damage and subsequent presence of insects; more than 82 % of the scorched trees exhibited evidence of colonization, and only 6 % of undamaged trees were successfully colonized. Tree mortality increased with higher percentages of crown scorch, as did infestation by Dendroctonus and Ips: a tree 15 cm in diameter with half of its crown scorched has a 4.5 % probability of dying, which increases to 51 % when bark insect infestation is added to the model. Source

Medina-Moreno S.A.,Polytechnic University of Pachuca | Perez-Cadena R.,Polytechnic University of Pachuca | Jimenez-Gonzalez A.,Polytechnic University of Francisco I. timber | Tellez-Jurado A.,Polytechnic University of Pachuca | Lucho-Constantino C.A.,Polytechnic University of Pachuca
Bioresource Technology | Year: 2012

A biodecolorization model that considers the simultaneous mechanism of biosorption and biodegradation of a synthetic dye by immobilized white-rot fungus Trametes subectypus B32 in a fixed bed bioreactor was developed. The model parameters (biokinetic, biosorption and macroscopic transport) were determined by independent experiments. The biodecolorization model was used to determine the effect of variables such as immobilized biomass content, volumetric flow of wastewater, dye feeding concentration and initial dye concentration. By means of the model was possible to predict in the steady state, the limits of immobilized T. subectypus to biodecolorize polluted influent, being the model predictions similar in extent to previous reports. A dimensionless module of biosorption-bioreaction (φ=qmaxvz/rmaxL) was proposed to be used like criterion whenever one of the two mechanisms controls the biodecolorization. The model could be used for the designing and scaling up of fixed bed bioreactors with immobilized white-rot fungi for the biodecolorization process. © 2012 Elsevier Ltd. Source

Garcia-Lopez M.C.,Autonomous University of Nuevo Leon | Munoz-Flores B.M.,Autonomous University of Nuevo Leon | Chan-Navarro R.,Autonomous University of Nuevo Leon | Jimenez-Perez V.M.,Autonomous University of Nuevo Leon | And 5 more authors.
Journal of Organometallic Chemistry | Year: 2016

Here we report a green one-pot microwave-assisted synthesis of four push-pull organotin complexes derived from Schiff bases in good yields, which provides advancement over conventional method as it is simple, cost-effective and reproducible. All compounds were characterized by UV-Vis, TOF-HRMS, TGA-DTA, cyclic voltammetry, theoretical studies and compound 1 by X-ray single-crystal diffraction. Third-order nonlinear susceptibility χ(3) of complexes 1-4; ((E)-N′-(4-(diethylamino)-2-hydroxysalicylidine) nitrobenzohydrazidatediphenyl-tin (IV) (1), (E)-N′-(4-(diethylamino)-2-hydroxysalicylidine) nitrobenzohydrazidate di n-butyl-tin (IV) (2), ((E)-N′-(4-(methoxy)-2-hydroxysalicylidine) nitrobenzohydrazidate diphenyl-tin (IV) (3), (E)-N′-(4-(methoxy)-2-hydroxysalicylidine) nitrobenzohydrazidate di n-butyl-tin (IV) (4)) were measured via Maker-Fringes technique. In particular, compounds 1 and 2 display larger third-order nonlinearities than their methoxilated counterparts. © 2016 Elsevier B.V. All rights reserved. Source

Castaneda-Ovando A.,Autonomous University of the State of Hidalgo | Castaneda-Ovando A.,Polytechnic University of Francisco I. timber | Galan-Vidal C.A.,Autonomous University of the State of Hidalgo | Pacheco L.,Autonomous University of the State of Hidalgo | And 2 more authors.
Food Analytical Methods | Year: 2010

The anthocyanic composition of pigmented Mexican corn (Zea mays) has been investigated. Two extracts (hydrolyzed and non-hydrolyzed) were analyzed by HPLC at different temperatures. The separation profile obtained in chromatography was different for minor components but the main fraction was the same in both cases. The last anthocyanin fraction was collected and analyzed by MALDI-ToF MS. The compounds identified in the fraction were cyanidin-3-glucoside and pelargonidin-3-glucoside with an approximate content of 1 × 10 -6 and 1 × 10 -7 M for the hydrolyzed and non-hydrolyzed, respectively. © Springer Science + Business Media, LLC 2008. Source

Polytechnic University of Francisco I. timber | Entity website

Discover hidden collaborations