University Autnoma Metropolitana


University Autnoma Metropolitana

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Lara-Mayorga I.,University Autnoma Metropolitana | Duran-Hinojosa U.,University Autnoma Metropolitana | Arana-Cuenca A.,Polytechnic University of Pachuca | Monroy-Hermosillo O.,University Autnoma Metropolitana | Ramirez-Vives F.,University Autnoma Metropolitana
Environmental Technology | Year: 2010

In a previous paper, the authors showed that a slight aeration of a methanogenic reactor treating wastewater from the manufacture of polymeric resins could improve its performance, by increasing or allowing the removal of some of its contaminants, including vinyl acetate (VA). This paper reports the isolation under aerobic conditions of a VA-biodegrading axenic culture (strain C1) retrieved from the sludge of a slightly aerated methanogenic reactor at 1 mg L-1 d-1 of dissolved oxygen (DO). The axenic culture obtained was phenotypically (morphology, biochemical properties, VA consumption kinetics) and phylogenetically characterized. It formed white colonies with a branched and flat morphology on solid medium. The cell morphology of the isolate was bacillus with round endings and flagellate. The cells could form chains and were stained Gram-negative. The isolate required simple nutritional elements and had a growth rate of 0.024 h-1. The phylogenetical analysis showed that the aerobic bacterium was identified as Brevibacillus agri, with 99.3% similarity. The VA consumption kinetics in the methanogenic sludge were: volumetric consumption rate (rVA) of 1.74 ± 0.2 mg L -1 h-1, maximum specific consumption rate (q VAmax) of 3.98 mg g-1 volatile suspended solids (VSS) h-1 and affinity constant (KS) of 457.1 mg L-1. The same parameters in the axenic culture were 1.69 ± 0.04 mg L-1 h-1, 4.09 mg g-1 dry weight h-1 and 421.9 mg L-1, respectively. These results show evidence that the aerobic isolated bacterium, identified as Brevibacillus agri, carried out the VA hydrolysis in the slightly aerated methanogenic sludge, which is the limiting step in the degradation of this compound.

Lizardi-Jimnez M.A.,University Autnoma Metropolitana | Saucedo-Castaeda G.,University Autnoma Metropolitana | Thalasso F.,CINVESTAV | Gutirrez-Rojas M.,CINVESTAV
International Journal of Chemical Reactor Engineering | Year: 2011

Determination of mass transfer of non-water soluble substrates, as hexadecane (HXD), is an important constraint in three-phase airlift bioreactor. A new simple dynamic technique able to measure the hexadecane transfer rate (HTR) in a three-phase airlift bioreactor (ALB) was studied in this work. The image analyses technique allowed measuring the resulting specific mass transfer area (aHXD). Gas chromatography was used to measure time-dependent transferred HXD and therefore the HXD transfer coefficient (kLHXD). Finally, HTR was calculated by using the equation HTR = kLaHXD• (CHXD* - CHXD*) where CHXD* and CHXD are the saturation HXD-aqueous interphase and HXD aqueous phase concentration, respectively. As case study, we successfully applied to the measurement of HTR during a typical ALB microbial consortium culture; values from 0.010 to 0.042 mg HXD (L h)-1 were found. This technique could be used to compare similar simultaneously occurring parameters to assess mass transfer constraints in three-phase systems. Copyright © 2011 The Berkeley Electronic Press. All rights reserved.

Carrillo A. C.E.,University Autnoma Metropolitana | Ramos R. V.M.,University Autnoma Metropolitana
8th IEEE and IFIP International Conference on Wireless and Optical Communications Networks, WOCN2011 | Year: 2011

Despite the significative differences between ad hoc networks and Infrastructure Wireless Mesh Networks (iWMNs), the routing schemes designed specifically for the formers have been considered as a potential solution for the routing dilemma in the latter; however, the performance and effects of such approach have not been deeply studied. In this paper we extend some features of popular reactive (AODV) and proactive (DSDV) routing protocols to be used under the hierarchical architecture of iWMNs. Through extensive simulations, we acquire a set of results that evidence the pros and cons of using these mechanisms. The results we get in this work allow us to identify design directions for future iWMNs routing protocols. © 2011 IEEE.

Perez-Pimentel Y.,Chiapas Polytechnic University | Osuna-Galan I.,Chiapas Polytechnic University | Villegas-Cortez J.,University Autnoma Metropolitana | Aviles-Cruz C.,University Autnoma Metropolitana
Proceedings of Special Session 2014 13th Mexican International Conference on Artificial Intelligence: Advances in Artificial Intelligence, MICAI 2014 | Year: 2014

The Content-Based Image Retrieval (CBIR) techniques comprise methodologies intended to retrieve self-content descriptors over the image data set being studied according to the type of the image. The main purpose of CBIR consists in classifying images avoiding the use of manual labels related to understanding of the image by the human being vision. In this work we provide a new CBIR procedure which works with local texture analysis, and which is developed in a non supervised fashion, clustering the local achieved descriptors and classifying them with the use of a K-means algorithm supported by the genetic algorithm. This method has been deployed in LabVIEW software, programming each part of the procedure in order to implement it in hardware. The results are very promising, reaching up to 90% of recall for natural scene classification. © 2014 IEEE.

Sanchez M. L.D.,University Autnoma Metropolitana | Ramos R. V.M.,University Autnoma Metropolitana
8th IEEE and IFIP International Conference on Wireless and Optical Communications Networks, WOCN2011 | Year: 2011

Radio Frequency IDentification (RFID) is a technology used on a wide set of applications. One of its main advantages is its ability of identifying objects in a wireless fashion with no contact or a direct sight line among the communicating devices. By improving the underlying collision resolution protocol in an RFID system, the power consumption of such devices is improved as well. In this paper, we present a new p-persistent CSMA collision resolution protocol for RFID systems. We compare our protocol with a non-persistent CSMA protocol previously proposed in the literature as well as with the ISO180007 standard. By measuring the average identification time for a wide range of tags, we show by simulation that our protocol outperforms both protocols. © 2011 IEEE.

Charleston-Villalobos S.,University Autnoma Metropolitana | Martinez-Hernandez G.,University Autnoma Metropolitana | Gonzalez-Camarena R.,Health Science University | Chi-Lem G.,National Institute of Respiratory Diseases | And 2 more authors.
Computers in Biology and Medicine | Year: 2011

This work deals with the assessment of different parameterization techniques for lung sounds (LS) acquired on the whole posterior thoracic surface for normal versus abnormal LS classification. Besides the conventional technique of power spectral density (PSD), the eigenvalues of the covariance matrix and both the univariate autoregressive (UAR) and the multivariate autoregressive models (MAR) were applied for constructing feature vectors as input to a supervised neural network (SNN). The results showed the effectiveness of the UAR modeling for multichannel LS parameterization, using new data, with classification accuracy of 75% and 93% for healthy subjects and patients, respectively. © 2011 Elsevier Ltd.

Aguilar N.,University Autnoma Metropolitana | Cadena M.,University Autnoma Metropolitana | Cadena M.,University Autnoma Metropolitana Iztapalapa | Sacristan E.,University Autnoma Metropolitana Iztapalapa | And 2 more authors.
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2011

The aim of this work was to build up a new monitoring technique for the lung preservation. The medical aside problem is to measure the integrity and functionality of the lung tissue, specifically at cellular preservation level in order to improve the survival time until it is grafted. The Impedance monitoring technique for diagnosis edema development is the key in this new technique. The hypothesis was that lung edema formation is highly correlated with the reactance changes so that a rat lung perfusion model was considered as a good model to produce edema in vitro. To prove that pulmonary edema can be induced increasing the venous pressure and the perfusion time, the reactance and hemodynamic parameters were recorder in 16 pulmonary blocks of Wistar rats as methodology. Results showed statistical changes in each pulmonary block weight as a consequence to apply 7.51.2 and 10.21.7 mmHg venous pressure (multiple samples, Anova, p0.05). These edema weights were correlated with the reactance changes giving 0.6 (p0.05, Pearson). Also, data analysis showed significant differences in reactance with the time of perfusion at 16, 30, and 50 min when venous pressure level were intermittent switched from 7.5 to 10.2 mmHg. The conclusion was this preliminary evidence sustains that reactance measurement is a good technique for monitoring the lung edema level in rats. However, more research should be continuing in bigger animal models in order to prove the validity and application of this monitoring technique in human lungs. © 2011 IEEE.

Angulo J.C.,University of Granada | Antolin J.,University of Zaragoza | Antolin J.,University of Granada | LOpez-Rosa S.,University of Granada | And 2 more authors.
Physica A: Statistical Mechanics and its Applications | Year: 2011

A generalization of the original JensenShannon divergence (JSD) is presented in this work, which gives rise to a non-extensive one-parameter divergence providing a powerful dissimilarity measure between electronic distributions. The analysis performed in this study employs the JTD measure to compare one-particle densities of neutral and ionized atomic systems, that generalizes and improves some previous results based on other measures of divergence. Such an improvement mainly arises from the capability of JTD to modify, by means of its order parameter, the relative contribution of specific relevant regions of the atomic densities under comparison, in both position and momentum spaces. Relevant information of the ionization processes attending to structural pattern and periodicity is found, as well as the strong correlation between extremal values of the neutralcation JTD and those of the atomic ionization potential. Similar conclusions are obtained from processes involving an anion. The analysis includes a study of the dependence of JTD on its order for fixed atomic couples. © 2010 Elsevier B.V. All rights reserved.

Rodrguez R.F.,National University of Costa Rica | Salinas-Rodrguez E.,University Autnoma Metropolitana | Maldonado A.,University of Sonora | Hernndez-Zapata E.,University of Sonora | Cocho G.,National University of Costa Rica
Physica A: Statistical Mechanics and its Applications | Year: 2011

We suggest that the cytoskeleton in contact with the inner surface of biological membranes in cells exhibiting tensegrity, may be considered as a system near critical conditions. This feature will influence the dynamical processes, such as diffusion, associated with the membrane's fluctuations induced by the surrounding medium. In this work we analyze a model for the diffusion of particles attached to the membrane due to the transverse membrane fluctuations when the surrounding fluid is near a critical state. We describe these fluctuations by a multiplicative Langevin equation with colored noise which accounts for the rheological nature of the medium. From the associated FokkerPlanck equation we calculate analytically the mean square displacement (MSD) and the dynamic structure factor (DSF) of the particles. In the limit of additive white noise, it is well known that the MSD and the DSF exhibit sub-diffusive behavior with a scaling MSD∼t23 and DSF∼exp(ΓkAWt) 23. In contrast, we show that for the case of external fluctuations arising from criticality and modeled by an OrnsteinUhlenbeck multiplicative noise, the behavior of these quantities becomes supradiffusive, with scalings MSD∼t53 and DSF∼exp(ΓkMCt)53. We suggest that this supradiffusive behavior might be of importance for the biological functions of the cell and compare our work with other approaches which also predict the same transition from a sub-diffusive to a supra-diffusive regime. © 2010 Elsevier B.V. All rights reserved.

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