Victoria de Durango, Mexico
Victoria de Durango, Mexico

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Navar J.,Technological Institute of Ciudad Victoria | Dominguez-Calleros P.A.,Universidad Juárez del Estado de Durango | Rodriguez-Flores F.J.,Technical University Durango | Lizarraga-Mendiola L.,Autonomous University of the State of Hidalgo | And 2 more authors.
Mathematical and Computational Forestry and Natural-Resource Sciences | Year: 2016

The aim of this research was to develop a growth and yield model for predictions of the basal area and timber volume of reforested stands in degraded, arid, semi-arid and dry-temperate lands of northern Mexico. In total, 124 forest stands (chronosequences) were sampled for allometric features (basal and breast height diameter, canopy height and canopy cover); data from 75% of the stands were used for model tting and data from the remaining 25% of the stands were used for the model validation. The potential timber volume and basal area growth were determined for each reforested species. The growth rates of reforested native coniferous species in the states of Durango (P. durangensis Martinez, P. cooperi C.E. Blanco, and P. engelmannii Carriere) and Nuevo Leon (P. pseudostrobus Lindl.) were higher than those of pine species not native to south Central Durango (P. arizonica Engelmann), eastern Nuevo Leon (P. cembroides Zucc., P. pinceana Gordon, and P. nelsonii Shaw) and Coahuila (P. halepensis Mill.). Because forest stands are often reforested at high seedling densities, the productivity is higher than that of pre-existing native forests communities. Therefore, this practice is recommended in order to increase timber stocks and the productivity of Mexico's degraded temperate and semi-arid forests. © 2016 Publisher of the Mathematical and Computational Forestry & Natural-Resource Sciences.

Rodriguez-Flores F.J.,Technical University Durango | Aguirre-Salado C.A.,Autonomous University of San Luis Potosi | Miranda-Aragon L.,Autonomous University of San Luis Potosi
Agrociencia | Year: 2013

The objective of this study was to model the dynamics of annual evaporation (E) during radial growth of Pinus cooperi Blanco, which is economically and ecologically important for northern México. Dendrochronological data were used to identify a model that would, with instrumental records, relate E for the period 1964 to 2010. The correlation and regression analyses showed that E negatively affects growth during the months previous to the growth season and during the summer of the growth year (June and July). E is a significant variable that can explain water stress and that can have implications for management of P. cooperi in the face of climatic variation.

de Jesus Rodriguez-Flores F.,Technical University Durango | Dominguez-Calleros P.A.,UJED
Annals of Forest Research | Year: 2013

Taper functions are required in modern forest management in estimation of the end forest products, to be classified for their life time in the environment. Based on a sample of 1640 trees of 10 species measured in volume, biomass and taper project on Mexico's northern temperate, mixed, uneven-aged coniferous forests, 12 stem profile taper functions were fitted in order to select the equation that provides better diameter estimates at commercial tree height. Although several equations fitted better specific tree species, the Newnham (1990) equation consistently yielded better diameter estimates at any length of the stem for all studied species. The confidence intervals on the Newnham (1990) equation parameters showed that each species has an unique stem profile and, therefore, single parameter equations are reported. Because of lack of analytical integration, the recommended taper equation (when numerically integrated) provided compatible, unbiased total bole volume when contrasted to conventional timber volume assessments. Data for 637 circular, 1/10 ha, plots from temperate forests of Central Durango, Mexico estimated a mean of 135 m3 ha-1, of which 18, 59, 30, and 17 m3 ha-1 could be classified as poles, sawn wood, plywood and secondary forest products, respectively. This information can be used for the planning of the forest industry to optimize forest products derived from timber harvesting, as well as for estimating other environmental components.

Navar J.,Natural Resource Management | Rios-Saucedo J.,INIFAP Valle del Guadiana | Perez-Verdin G.,Natural Resource Management | Rodriguez-Flores F.D.J.,Technical University Durango
Journal of Arid Environments | Year: 2013

Calculations of dry tree, plot and regional aboveground biomass, M, and assessments of complex diverse forests remain key challenges in the implementation of conventional and sustainable projects. This study reports a set of robust regional equations and the application of several allometric tree and plot M equations in Mexican arid and semi-arid forest communities. The data were collected from 1084 tree M fitting models, and 195 arid and semi-arid and 206 mesquite trees and 55 plot datasets were used to validate the models. Theoretical, semi-empirical and empirical models with exogenous variables, as well as wood specific gravity, diameter, top height, and form-factor values, were used to evaluate aboveground biomass. Empirical computer-based equations projected more consistently similar tree M assessments than did semi-empirical or theoretical models. Therefore, empirical models are recommended for assessments of tree and plot M, and future allometry research should properly address independent variables in more theoretical models. The large sample size, model richness, economic and ecological importance, and wide coverage of this dataset make it useful for estimating several biogeochemical and bioenergy density parameters and contribute to the body of knowledge regarding heterogeneity in dry forest stand structures. © 2013 Elsevier Ltd.

Rodriguez-Flores F.D.J.,Technical University Durango | Nava J.,Technological Institute of Ciudad Victoria
Tropical and Subtropical Agroecosystems | Year: 2016

Aboveground tree biomass (bole, branches and foliage), M, plays a key role in the conventional and sustainable management of forest communities. The standard approach to assess tree or plot M is harvesting trees, developing and fitting allometric equations to trees or forest inventory plot data. In the absence of local tree allometry, it is usually recommended to fit off site allometric equations to evaluate tree or plot M. This research aims: (a) to develop an updated on site allometric equation (b) to fit available off site allometric equations to destructively harvested trees and (c) to fit available allometric equations to plot M of Mexico's Sinaloan tropical dry forests to understand sources of inherent tree and plot M variability. Results showed that: (a) the improved on site allometric equation increases precision in contrast to the conventional biomass equation previously reported as well as to off site tree M equations, (b) off site allometry projects tree and plot M deviates by close to one order of magnitude. Two tested and recommended approaches to increase tree and plot M precision when fitting off site equations are: (i) to use all available tree allometric functions to come up with a mean equation or (ii) to calibrate off site equations by fitting new, local parameters that can be calculated using statistical programs.These options would eventually increase tree and plot M precision in regional evaluations.

Ordaz-Diaz L.A.,Technical University Durango | Rojas-Contreras J.A.,Durango Institute of Technology | Flores-Vichi F.,Regional Development Centre | Flores-Villegas M.Y.,Technical University Durango | And 3 more authors.
BioResources | Year: 2016

The aim of this study was to identify cellulolytic fungal strains capable of degrading cellulose from an aerated lagoon in a pulp and paper mill. Four fungal strains that were found to be highly active were isolated on carboxymethyl cellulose (CMC) and suggested to be CMCase/endoglucanase. The identified strains were Aspergillus niger, Penicillium sp., Aspergillus fumigatus, and Mucor sp. All the strains were studied in terms of cultural morphological characteristics and microscopic examinations. The endoglucanase with the highest isolate production was Penicillium sp., which also showed the highest qualitative endoglucanase activity (1.3 cm), in addition to the main activity of endoglucanase with 297 mmol/mg.min after 116 h. The results indicated that CMC is able to induce endoglucanase enzyme production and that the fungal isolates showed significant cellulose degradation properties.

Ordaz-Diaz L.A.,Durango Institute of Technology | Ordaz-Diaz L.A.,Technical University Durango | Rojas-Contreras J.A.,Durango Institute of Technology | Rutiaga-Quinones O.M.,Durango Institute of Technology | And 3 more authors.
BioResources | Year: 2014

Pulp and paper mills are a major source of pollution, generating huge amounts of intensely colored effluent that goes to the receiving end of a wastewater treatment plant. The biochemical oxygen demand test (BOD5) relies heavily on the microorganism metabolic capability added to the test as seeding material. The seeding material in the testing is obtained from sewage sampling or from commercial sources. Specific organic pollutants that are present in paper and pulp mill effluent can only be degraded by specific microbes; therefore, common sewage or synthetic seed may lead to erroneous BOD5 estimations. In this study, specific microbial species were selected to evaluate their degradation efficiency, both individually and in combination. The microorganisms selected in the formulated seed exhibit BOD5 in a reproducible and synergistic manner. The formulation of this specific microbial consortium can be used to develop bioremediation strategies.

Navar J.,National Polytechnic Institute of Mexico | Rodriguez-Flores F.D.J.,Technical University Durango | Dominguez-Calleros P.A.,Universidad Juárez del Estado de Durango | Perez-Verdin G.,National Polytechnic Institute of Mexico
International Journal of Ecology | Year: 2014

This research examines the diversity-productivity relationship in a semiarid scrubland, initially under late successional conditions and subsequently under early successional conditions created by experimental clearing, to explore the roles that productivity and stochastic mortality play in species exclusion in this environment. A total of fifteen plots were studied by measuring environmental conditions and biomass components of shrubs and seedlings. These stands were distributed along a productivity gradient across five different landforms. A hypothesis about the stochastic self-thinning mortality model along the gradient was evaluated with the diversity- productivity-environment data. The diversity-productivity relationship was linear and reversed between the early and late succession stages. The hypothesis of stochastic mortality of species exclusion was rejected in the early stages of succession and partially accepted in the mature stage of succession. Species exclusion was negatively related to productivity gradients, suggesting that strong interspecific competition occurs in high productivity plots and that a larger number of species can survive in higher abiotic stress landscapes. Further research is needed to understand the temporal and spatial variations of the ecological interactions that shape this plant community. © 2014 Jose Navar et al.

Ordaz-Diaz L.A.,Technical University Durango | Valle-Cervantes S.,Durango Institute of Technology | Rojas-Contreras J.A.,Durango Institute of Technology | Rodriguez-Flores F.J.,Technical University Durango | Bailon-Salas A.M.,Durango Institute of Technology
BioResources | Year: 2016

A pilot-scale aerated lagoon was used for the aerobic treatment of pulp and paper mill effluent from September 1 to December 1, 2014. The aerated lagoon was installed at the chemistry laboratory in the Chemical Engineering Department at the Durango Institute of Technology and was fed with real pulp and paper mill effluent. The experimental work was run under various operating conditions. The operating parameters (total and volatile suspended solids (VSS) and dissolved oxygen concentration (DO)) and environmental variables (temperature, pH, COD, and BOD5 of influent water) were monitored daily. In all the experiments conducted, the aerated lagoon generated an effluent of optimal quality complying with the requirements of SEMARNAT (2003) and CONAGUA (2003). A model that explains the behavior of the system under realistic operating conditions was obtained. The model indicated an optimal DO of approximately 4 mg/L for concentrations up to 1000 mg/L, showing variations in concentrations above this value. This data indicate that the flexibility of the bacterial formulation and its ability to adapt to environmental changes play an important role in the stability of an aerated lagoon.

Salazar-Munoz Y.,Durango Institute of Technology | Garcia-Caballero B.E.,Durango Institute of Technology | Munoz-Rios R.,Durango Institute of Technology | Lopez-Perez G.A.,Technical University Durango | Ruano-Calderon L.A.,Hospital General 450
International Power Electronics Congress - CIEP | Year: 2016

Clinical evaluation of the patellar reflex is one of the most frequent diagnostic method used by physicians and medical specialists. This test is usually done and is diagnosed manually, resulting in high variability during the assessment. The aim of this work is to determine if there exist a relation between velocity and the magnitude of reflex response. Methodology: It was used a precalibrated hammer designed for this test, to induce the patellar reflex and measure the angular rate of the leg during the course of the reflex test. The measurement system integrate an impact sensor to detect the hammer stroke; and an inertial measurement unit (IMU) to measure the angular rate of the leg response after it receives the hammer stroke on the tendon. The average angular rate signals were grouped based on the corresponding NINDS level. Results: The maximum value reached by the mean signal of 3+ group is 38 degrees per second. This magnitude is attenuated in a 31% to 2+ group, a 76% to 1+ group and 95% to 0+ group. These results are significant due to the relation between the NINDS level and the magnitude of the angular rate of the reflex response, and add features which can be useful in the quantification of the patellar reflex. © 2016 IEEE.

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