Tabasco, Mexico

Universidad Juárez Autónoma de Tabasco is a public institution of higher learning located in Villahermosa, Tabasco, Mexico. The mission of the university is "to prepare professionals with broad and deep expertise in their area of study to fill the needs of Tabasco and the country at large." UJAT is the largest and most prominent university in the state of Tabasco. During the 2007-2008 academic year the University enrolled 35,271 students and had a teaching staff of over 2,000. For the same school year the University offered bachelor's degrees in 36 disciplines, master's degrees in 26 areas, three doctoral degrees, and post-graduate Certificates in 17 graduate areas of specialization . The University grants law, education, management, engineering, medicine, architecture, nursing, and dentistry degrees, plus some 30 additional degrees in other fields of study. Wikipedia.

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Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University | Cruz-Suarez D.,Juarez Autonomous University of Tabasco
Journal of Mathematical Analysis and Applications | Year: 2017

This work concerns with Markov chains on a finite state space, which is endowed with a cost function. The evolution of the chain is observed by an agent with constant risk-sensitivity and, assuming that the state space is a communicating class, the relation between the risk-sensitive discounted and average performance criteria is studied. It is proved that, as the discount factor increases to 1, an appropriate normalization of the discounted value function converges to the average cost. Also, it is shown that if the classical normalization used in the risk-neutral case is applied in the risk-sensitive context, then the normalized discounted value function converges to an arithmetic mean of the average cost. © 2017 Elsevier Inc.

Carbajal-Dominguez A.,Juarez Autonomous University of Tabasco | Bernal J.,Juarez Autonomous University of Tabasco | Martin-Ruiz A.,Juarez Autonomous University of Tabasco | Niconoff G.M.,National Institute of Astrophysics, Optics and Electronics
Optics Express | Year: 2010

An alternative method to generate J0 Bessel beams with controlled spatial partial coherence properties is introduced. Far field diffraction from a discrete number of source points on an annular region is calculated. The average for different diffracted fields produced at several rotation angles is numerically calculated and experimentally detected. Theoretical and experimental results show that for this particular case, the J0 Bessel beam is a limit when the number of points tends towards infinity and the associated complex degree of coherence is also a function of the number of points. © 2010 Optical Society of America.

Corzo C.A.,Juarez Autonomous University of Tabasco | Waliszewski K.N.,Instituto Tecnologico De Veracruz | Welti-Chanes J.,Monterrey Institute of Technology
Food Chemistry | Year: 2012

Optimal pH and temperature conditions for proteolytic activity of pineapple fruit bromelain were determined using five different substrates: azocasein and azoalbumin (pH 3-10 at 20-70°C), casein and sodium caseinate (pH 2-10 at 20-70°C), and haemoglobin (pH 2-6.5 at 30-60°C). Fruit bromelain has shown optimum activity at pH 7.5 for azoalbumin and at 6.5 for azocasein, all at 55°C. Fruit bromelain activity determined with casein and sodium caseinate has shown optimum activity at 59°C, while the optimum pH was 7.7 for casein and 6.5 for sodium caseinate. Optimum hydrolysis conditions of fruit bromelain towards haemoglobin showed a sharp peak at an acidic pH 2.9 at 37°C. The lowest results of K m and the highest results of V max/ K m were found for azocasein and azoalbumin. These substrates are highly recommended for fruit bromelain activity determination. © 2012 Elsevier Ltd. All rights reserved.

Hernandez-Franyutti A.,Juarez Autonomous University of Tabasco | Uribe M.C.,National Autonomous University of Mexico
Journal of Morphology | Year: 2012

We describe seasonal variations of the histology of the seminiferous tubules and efferent ducts of the tropical, viviparous skink, Mabuya brachypoda, throughout the year. The specimens were collected monthly, in Nacajuca, Tabasco state, Mexico. The results revealed strong annual variations in testicular volume, stages of the germ cells, and diameter and height of the epithelia of seminiferous tubules and efferent ducts. Recrudescence was detected from November to December, when initial mitotic activity of spermatogonia in the seminiferous tubules were observed, coinciding with the decrease of temperature, photoperiod and rainy season. From January to February, early spermatogenesis continued and early primary and secondary spermatocytes were developing within the seminiferous epithelium. From March through April, numerous spermatids in metamorphosis were observed. Spermiogenesis was completed from May through July, which coincided with an increase in temperature, photoperiod, and rainfall. Regression occurred from August through September when testicular volume and spermatogenic activity decreased. During this time, the seminiferous epithelium decreased in thickness, and germ cell recruitment ceased, only Sertoli cells and spermatogonia were present in the epithelium. Throughout testicular regression spermatocytes and spermatids disappeared and the presence of cellular debris, and scattered spermatozoa were observed in the lumen. The regressed testes presented the total suspension of spermatogenesis. During October, the seminiferous tubules contained only spermatogonia and Sertoli cells, and the size of the lumen was reduced, giving the appearance that it was occluded. In concert with testis development, the efferent ducts were packed with spermatozoa from May through August. The epididymis was devoid of spermatozoa by September. M. brachypoda exhibited a prenuptial pattern, in which spermatogenesis preceded the mating season. The seasonal cycle variations of spermatogenesis in M. brachypoda are the result of a single extended spermiation event, which is characteristic of reptilian species. © 2012 Wiley Periodicals, Inc.

Gonzalez-Castro T.B.,Juarez Autonomous University of Tabasco | Juarez-Rojop I.,Juarez Autonomous University of Tabasco | Lopez-Narvaez M.L.,Research Center Genomica | Lopez-Narvaez M.L.,Hospital General Of Yajalon | Tovilla-Zarate C.A.,Juarez Autonomous University of Tabasco
BMC Psychiatry | Year: 2014

Background: It is widely acknowledged that suicidal behavior (SB) has a genetic influence. As a consequence, molecular genetic studies have been mostly conducted on serotonergic genes. One of the most promising candidate genes of this system is tryptophan hydroxylase (TPH). Although there have been several positive studies associating TPH genes and SB, the evidence is not entirely consistent. Therefore, we performed a meta-analysis to gain a better understanding into this issue.Methods: The meta-analysis was conducted with 37 articles of genetic association studies of TPH-1 (A218C and A779C) and TPH2 (G-703 T, A-473 T and G19918A) genes. To analyze the association of these variants with SB we used the following models: allelic, additive, dominant and recessive. In addition, we performed a sub-group analysis by Caucasian and Asian populations using the same four models.Results: TPH-1 gene variants showed a positive significant association with SB, but only in the fixed effects models. With regard to TPH-2 gene variants we could not find an association with SB.Conclusions: The study provides evidence that A218C/A779C TPH-1 variants may be a risk factor to manifest SB at the clinical level, which is in agreement with previously reported meta-analyses. With regard to G-703 T/A-473 T/G19918A TPH-2 variants, our up-to-date meta-analysis could not detect any significant association between those genetic variants and SB. However, these results should be interpreted with caution since further studies need to be undertaken using larger sample sizes in different ethnic populations to confirm our findings. © 2014 González-Castro et al.; licensee BioMed Central Ltd.

Yang C.-S.,University College London | Mora-Fonz J.M.,Juarez Autonomous University of Tabasco | Catlow C.R.A.,University College London
Journal of Physical Chemistry C | Year: 2013

The nucleation mechanism of zeolite A is investigated by means of Density Functional Theory (DFT) calculations. We calculated the Gibbs free energy change for the polymerization and cyclization reactions involved in the nucleation of zeolite A in the gas phase and solution between 298 and 450 K. Our analysis reveals that the four-ring species formed could be the most likely to participate in the nucleation of zeolite A, and its nucleation mechanism could proceed by a reaction route which involves the formation of the double-four-ring. © 2013 American Chemical Society.

Valdes-Manzanilla A.,Juarez Autonomous University of Tabasco
Natural Hazards | Year: 2016

It is presented a chronology of historical floods during sixteenth–twentieth centuries in the Mexican states of Tabasco and Chiapas. There were 41 historical flooding events during 1528–1948, 16 of them were catastrophic flooding and 25 were extraordinary ones. There were periods of historical floods between 1651–1652, 1676–1677, 1679–1680, 1888–1889, 1927–1929, 1931–1933 and 1940–1944. During the instrumental period (1949–1999) there were only four extraordinary flood events in the Usumacinta River. Most of flood periods coincided with the warm phase of the Atlantic Multidecadal Oscillation (AMO). The flood period of 1940–1944 was as long as the most recent one (2007–2011). Wavelet analysis found flood periodicities of 2.5, 52 and 83 years, but only the last one was statistical significant and their occurrence was in phase with the AMO. Logistic regression showed that AMO index was the most correlated index with flood events. In fact, the odds ratio showed that floods were 1.90 times more likely to occur when AMO index was positive. This regression model predicted correctly 64.70 % of flood occurrences during twentieth century using its flood information only as validation data. © 2015, Springer Science+Business Media Dordrecht.

The aim of this study was to evaluate the actions of coenzyme Q10 (CoQ10) on rats with a cholesterol-rich diet (HD) and high doses of atorvastatin (ATV, 0.2, 0.56 or 1.42 mg/day). Two experiments were done, the first one without coenzyme Q10 supplementation. On the second experiment all groups received coenzyme Q10 0.57 mg/day as supplement. After a 6-week treatment animals were sacrificed, blood and liver were analyzed and liver mitochondria were isolated and its oxygen consumption was evaluated in state 3 (phosphorylating state) and state 4 (resting state) in order to calculate the respiratory control (RC). HD increased serum and hepatic cholesterol levels in rats with or without CoQ10. ATV reduced these values but CoQ10 improved even more serum and liver cholesterol. Triacylglycerols (TAG) were also lower in blood and liver of rats with ATV + CoQ10. HDL-C decreased in HD rats. Treatment with ATV maintained HDL-C levels. However, these values were lower in HD + CoQ10 compared to control diet (CD) + CoQ10. RC was lessened in liver mitochondria of HD. The administration of ATV increased RC. All groups supplemented with CoQ10 showed an increment in RC. In conclusion, the combined administration of ATV and CoQ10 improved biochemical parameters, liver function and mitochondrial respiration in hypercholesterolemic rats. Our results suggest a potential beneficial effect of CoQ10 supplementation in hypercholesterolemic rats that also receive atorvastatin. This beneficial effect of CoQ10 must be combined with statin treatment in patient with high levels of cholesterol.

Tovilla-Zarate C.,Juarez Autonomous University of Tabasco
BMC psychiatry | Year: 2011

The polymorphism COMTval158met has been associated with suicidal behavior in case-control and meta-analysis studies, but results and conclusions remain controversial. The objective of this study was to examine the association between COMT val158met with suicidal behavior in a case-control study and to assess the combined evidence -this case-control study and available data from other related studies- we carried out a meta-analysis. We conducted a case-control study with 105 patients with suicide attempts and 236 controls. Subsequently, we performed a meta-analysis of published genetic association studies by searching through Medline, PubMed and Web of Science databases. No significant differences were found in the distribution of alleles (χ2 = 0.33, 1 df, p = 0.56) or genotypes (χ2 = 2.36, 2 df, p = 0.26). The meta-analysis comprising 12 association studies (including the present one) showed that the risk COMTmet allele of COMTval158/met is not associated with suicidal behavior (OR: 1.09, 95% CI: 0.97-1.23), even in the absence of heterogeneity (OR: 1.09, 95% CI: 0.97-1.23). Our results showed no association between COMTval158/met and suicidal behavior. However, more studies are necessary to determine conclusively an association between COMT and suicidal behavior.

Valdes-Manzanilla A.,Juarez Autonomous University of Tabasco
Atmosfera | Year: 2015

This study presents an analysis of the summertime mesoscale convective systems (MCSs) that developed in northwestern Mexico during the strong ENSO events of 1997-1999. From the analysis of geostationary data, results indicate that the largest number of MCSs was associated with the 1997 El Niño event throughout a longer active period. During the La Niña event of 1999 fewer MCSs were observed, which had developed over a shorter active period. The occurrence of MCSs is linked to the location of the ridge and the anticyclonic anomalies at 500 hPa and 200 hPa, respectively. © 2015,Universidad Nacional Autonoma de Mexico.All rights reserved

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