Time filter

Source Type

Panindícuaro de la Reforma, Mexico

Salem A.Z.M.,Mexico State University | Elghandour M.M.M.,Mexico State University | Berasain M.A.M.,Mexico State University | Jimenez F.J.P.,Autonomous University of Hidalgo | And 4 more authors.
Journal of Integrative Agriculture | Year: 2015

An in vitro gas production (GP) technique was used to investigate the effects of combining different doses of Salix babylonica extract (SB) with exogenous fibrolytic enzymes (EZ) based on xylanase (X) and cellulase (C), or their mixture (XC; 1:1 v/v) on in vitro fermentation characteristics of a total mixed ration of corn silage and concentrate mixture (50:50, w/w) as substrate. Four levels of SB (0, 0.6, 1.2 and 1.8 mL g-1 dry matter (DM)) and four supplemental styles of EZ (1 μL g-1 DM; control (no enzymes), X, C and XC (1:1, v/v) were used in a 4×4 factorial arrangement. In vitro GP (mL g-1 DM) were recorded at 2, 4, 6, 8, 10, 12, 24, 36, 48 and 72 h of incubation. After 72 h, the incubation process was stopped and supernatant pH was determined, and then filtered to determine dry matter degradability (DMD). Fermentation parameters, such as the 24 h gas yield (GY24), in vitro organic matter digestibility (OMD), metabolizable energy (ME), short chain fatty acid concentrations (SCFA), and microbial crude protein production (MCP) were also estimated. Results indicated that there was a SB×EZ interaction (P<0.0001) for the asymptotic gas production (b), the rate of gas production (c), GP from 6 to 72 h, GP2 (P=0.0095), and GP4 (P=0.02). The SB and different combination of enzymes supplementation influenced (P<0.001) in vitro GP parameters after 12 h of incubation; the highest doses of SB (i.e., 1.8 mL g-1 DM), in the absence of any EZ, quadratically increased (P<0.05) the initial delay before GP begins (L) and GP at different incubation times, with lowering b (quadratic effect, P<0.0001) and c (quadratic effect, P<0.0001; linear effect, P=0.0018). The GP was the lowest (P<0.05) when the highest SB level was combined with cellulose. There were SB×EZ interactions (P<0.001) for OMD, ME, the partitioning factor at 72 h of incubation (PF72), GY24, SCFA, MCP (P=0.0143), and pH (P=0.0008). The OMD, ME, GY24 and SCFA with supplementation of SB extract at 1.8 mL g-1 DM were higher (P<0.001) than the other treatments, however, PF72 was lower (quadratic effect, P=0.0194) than the other levels. Both C and X had no effect (P>on OMD, pH, ME, GY24, SCFA and MP. The combination of SB with EZ increased (P<0.001) OMD, ME, SCFA, PF72 and GP24, whereas there was no impact on pH. It could be concluded that addition of SB extract, C, and X effectively improved the in vitro rumen fermentation, and the combination of enzyme with SB extract at the level of 1.2 mL g-1 was more effective than the other treatments. © 2015 Chinese Academy of Agricultural Sciences.

Navar J.,Natural Resource Management | Lizarraga-Mendiola L.,Autonomous University of Hidalgo
Geofisica Internacional | Year: 2013

Global warming is likely modifying the hydrological cycle of forested watersheds. This report set as objectives to: a) assess the hydrological variables interception loss, I, potential and actual evapotranspiration, E, Et, runoff, Q, and soil moisture content, θ; b) evaluate whether these variables are presenting consistent trends or oscillations that can be associated to global warming or climate variability; and c) relate θ to the number of wildfires and the burned area in Durango, Mexico. A mass balance approach estimated daily variables of the water cycle using sub-models for I and Et to calculate Q and θ for a time series from 1945 to 2007. Regression and auto-regressive and moving averaging (ARIMA) techniques evaluated the statistical significance of trends. The cumulative standardized z value magnified and ARIMA models projected statistically similar monthly and annual time series data of all variables of the water cycle. Regression analysis and ARIMA models showed monthly and annual P, I, E, and Et, Q, and θ do not follow consistent up or downward linear tendencies over time with statistical significance; they rather follow oscillations that could be adequately predicted by ARIMA models (r2 ≥ 0.70). There was a consistent statistical association (p ≤ 0.05) of θ with the number of wildfires and the area burned regardless of the different spatial scales used in evaluating these variables. The analysis shows seasonal variability is increasing over time as magnifying pulses of dryness and wetness, which may be the response of the hydrological cycle to climate change. Further research must center on using longer time series data, testing seasonal variability with additional statistical analysis, and incorporating new variables in the analysis.

Rubio E.,Autonomous University of Puebla | Mendoza D.,Instituto Nacional de Investigaciones Nucleares | Rodriguez V.,Autonomous University of Hidalgo | Castano V.M.,National Autonomous University of Mexico
Journal of Superhard Materials | Year: 2015

Sulfur-modified zirconia with various S contents have been characterized and analyzed for potential applications in dosimetry. The thermoluminescent signal induced by gamma radiation in pure zirconia and sulfated zirconia in the tetragonal phase has been considered. Experimental results show that the thermoluminescent glow peak depends on both the crystalline structure and sulfate concentration and that the response is linear for an ample range of irradiation. © 2015, Allerton Press, Inc.

Vidaurre D.,Technical University of Madrid | Rodriguez E.E.,National Polytechnic Institute of Mexico | Rodriguez E.E.,Autonomous University of Hidalgo | Bielza C.,Technical University of Madrid | And 2 more authors.
Journal of Neural Engineering | Year: 2012

In the spinal cord of the anesthetized cat, spontaneous cord dorsum potentials (CDPs) appear synchronously along the lumbo-sacral segments. These CDPs have different shapes and magnitudes. Previous work has indicated that some CDPs appear to be specially associated with the activation of spinal pathways that lead to primary afferent depolarization and presynaptic inhibition. Visual detection and classification of these CDPs provides relevant information on the functional organization of the neural networks involved in the control of sensory information and allows the characterization of the changes produced by acute nerve and spinal lesions. We now present a novel feature extraction approach for signal classification, applied to CDP detection. The method is based on an intuitive procedure. We first remove by convolution the noise from the CDPs recorded in each given spinal segment. Then, we assign a coefficient for each main local maximum of the signal using its amplitude and distance to the most important maximum of the signal. These coefficients will be the input for the subsequent classification algorithm. In particular, we employ gradient boosting classification trees. This combination of approaches allows a faster and more accurate discrimination of CDPs than is obtained by other methods.

Perez-Martinez R.,Autonomous University of Hidalgo | Esteva L.,National Autonomous University of Mexico
Journal of Earthquake Engineering | Year: 2012

A study is presented about the influence of infill masonry panels on the life-cycle expected performance functions of multi-story reinforced concrete frames exposed to severe seismic hazard conditions. Quantitative information is presented about present values of expected performance functions of a group of five-story systems located at a firm ground site. The group includes a bare frame system, designed in accordance with the applicable seismic design regulations, and a number of systems obtained by inserting several reinforced or unreinforced masonry wall panels, introduced with the aim of improving the expected seismic performance of the original system. © 2012 Copyright A. S. Elnashai & N. N. Ambraseys.

Discover hidden collaborations