Autonomous University of Carmen

El objetivo de esta investigación fue analizar los factores que influyen en el estrés académico en los estudiantes del último año de nivel medio superior. La metodología consistió en un estudio cuantitativo tipo observacional, que se desarrolló en la Escuela Preparatoria Diurna de la Universidad Autónoma del Carmen, ubicada en Ciudad del Carmen, Campeche, México. Se evaluaron 234 estudiantes que cursan el último año mediante un instrumento compuesto por 28 reactivos. El estudio reveló que la obtención de altas calificaciones y las perspectivas futuras son los estresores que más influyen en los estudiantes, así como también, la sobrecarga académica, los exámenes, la falta de tiempo para entrega de actividades y para descanso. Se concluyó que es importante considerar los factores que detonan el estrés para ayudar a los estudiantes a que aprendan a afrontarlos, a regularse a sí mismos, ya que el estrés académico detona padecimientos físicos y emocionales, los cuales pueden influir en la deserción escolar, el rendimiento académico y los índices de reprobación.

Nowadays, potable water supply has become a problem, involving different aspects such as water quality, pollution, pipes' quality, supply and demand of drinking water, water leaks, and supply cuts, among other aspects that have complicated the efficient use of potable water in urbanized regions. The objective of this chapter is to define potable water distribution network (PWDN) optimization as a complex problem, from the perspective of an NP-Hard problem, and the complexity as a variant of water distribution network optimization. The main result of the proposal is the definition of a problem that identifies the main variables involved in the supply of quality potable water as a global problem where each researcher can solve the main problem as one or propose solutions for different parts. The proposal simulation is oriented to present a brief solution related to the supply and demand of drinking water as a part of the PWDN.

Abstract The objective of this study is to understand the influence of the regional aquifer and surrounding fields over two clusters of giant oil, fractured carbonate reservoirs in the Mexican Gulf of Mexico (GoM). These reservoirs are referred to as Cluster-A and Cluster-B, and our goal is to predict the impact and influence of gas injection in Cluster-A and waterflooding in both clusters. Field-B1 pressure is declining and if it follows with the current trend, there will be difficulties to continue production from the existing wells, which mainly use electrical submersible pumps, since the pumps would operate outside their pressure range. For this reason it is was imperative to consider the implementation of a pressure maintenance program that would enable to continue producing within operative ranges of the artificial lift system. To implement a secondary recovery project of the large magnitude required, the different regional uncertainties must be reduced as much as possible. Since Field-B1 is hydraulically connected through a regional aquifer with other fields under operation, the following were considered: Quantify the energy of the regional aquifer Evaluate the dynamic behavior of the regional aquifer as it is influencing all fields simultaneously Understand the historical pressure behavior of Field-B1 (which is to be waterflooded) to determine the influence of the surrounding fields To fulfill these objectives, a simulation model including Cluster-A, Cluster-B, and surrounding fields was built. The model encompasses a total area of 2,000 km2. The aquifer was modeled explicitly using the simulation grid cells using a border region with pore volume and transmissibility multipliers to represent a large area to the south. The influences of production and water injection of surrounding fields (not explicitly modeled in this study) were included by representing these fields as pseudowells. To speed up the analysis and understanding of drive mechanisms and the impact of sensitivity variables to the history match, a coarse model was built and used to perform a large number of sensitivity runs. Findings and lessons learned from the coarse model were applied to the fine-grid model. The fine-grid model was history matched. As a result, the size and influence of the regional aquifer and connectivity of large limit faults located throughout the fields and aquifer was determined. By analyzing the time of flight along streamlines, the fluid transfer between fields and aquifer and relationship with events occurring in the fields was understood. The model was subsequently used to predict primary recovery, waterflooding, and gas-injection scenarios. We focused on the impact on pressure and production of Cluster-B, which is to be developed. In the scenarios, water is injected in Cluster-B, while nitrogen and hydrocarbon sour gas is injected in Cluster-A. The gas-injection rates are set to honor different voidage replacement ratios. As a result of the study, the aquifer size and characteristics were better understood, along with past and future interactions among fields. The most important conclusion is that the aquifer water drive in combination with the pressure maintenance program underway in Cluster-A through nitrogen injection of 100% voidage replacement ratio will not suffice to maintain the Cluster-B pressure above the necessary levels. It is imperative to implement an additional secondary recovery process to provide pressure support to Cluster-B, and thus ensure a stable operating range for the electrical submersible pumps installed in Field-B1.

Se propone una metodología para las universidades mexicanas en la gestión para la recolección de los residuos electrónicos como parte de su responsabilidad social, en el cuidado y protección del medio ambiente. Asimismo, se presenta un caso de éxito de la metodología propuesta aplicada a lo largo de 10 años desde su implementación en la universidad, logrando recabar un promedio de anual de dieciocho mil toneladas de residuos electrónicos evitando la contaminación ambiental en la zona considerada como Área de Protección de Flora y Fauna (APFF) Laguna de Términos.

The incidence of antibiotics and transcriptional regulation of ARGs in isolated bacteria from wastewater needs to be explored. By HPLC, in samples of untreated wastewater, ampicillin (49.74 ± 5.70 µg/mL), chloramphenicol (0.60 ± 0.03 µg/mL), tylosin (72.95 ± 2.03 µg/mL), and oxytetracycline (0.22 ± 0.01 µg/mL) was determined. Through metagenomic analysis identified 58 bacterial species belonging to 9 phyla and at least 14 species have shown resistance to a variety of antibiotics. Twenty-two bacterial isolates were proved to be resistant to fifteen antibiotics of new generation and used in medical research to combat infectious diseases. Fourteen strains were shown to harbor plasmids in size ranges of 2–5 Kb, 6–10 Kb and plasmids with size greater than 10 Kb. By quantitative PCR it was possible to identify genes sul, qnr, cat1, aadA1, and sat-1 gene were shown to be present in gDNA samples from treated and untreated samples of wastewater and by relative expression analysis, differential expression of cat1, ermB, act, and tetA genes was demonstrated in strains that showed identity with Escherichia coli, Bacteroides fragilis, and Salmonella thyphi, and that were stressed with different concentrations of antibiotics. The presence of ARGs in untreated water samples, as well as in bacterial isolates, was indicative that in these habitats there are microorganisms that can resist β-lactams, aminoglycosides, tetracyclines, sulfonamides, and quinolones.

In this study, the seismic responses of moment-resisting steel frames (MRSFs) with welded and post-tensioned connections under 28 artificial seismic sequences (mainshock–aftershock) are compared. For this aim, the mainshock are scaled at different ground motion intensity levels as a function of the spectral pseudo-acceleration corresponding to the fundamental period of vibration of the structure Sa(T1), whereas different intensity levels of the aftershocks are used for a percentage of the peak maximum acceleration of the mainshock. The seismic performance comparison of both structural systems is computed for the maximum, residual inter-story drift and hysteretic energy demands. The results show that post-tensioned frames significantly reduce the structural demands, especially in the case of residual inter-story drifts and hysteretic energy in comparison with moment-resisting steel frames with welded connections. The reductions in the structural response tend to be larger as the intensity of the aftershock tends to increase. Therefore, it is concluded that the use of post-tensioned connections is a great alternative to mitigate the seismic response of buildings subjected to seismic sequences.

This paper proposes the study of a robust control scheme for an Unmanned Surface Vehicle (USV) in a urban waterway using Visual Odometry (VO) for position estimation of the vehicle instead of traditional sensors. For different applications, a USV is required to operate in autonomous navigation mode and under various disturbances inherent to its environment as currents and waves. To achieve efficient operation, a robust control scheme is required to cope with such disturbances. The autonomous navigation is achieved by using VO to estimate the vehicle’s position for denied Global Positioning Systems (GPS) environments. A robust control scheme based on Sliding Modes (SM) control theory is designed and its convergence is guaranteed by means of Lyapunov analysis. The tracking capabilities under disturbance conditions using VO for position estimation are verified in simulation using the virtual world tool from Matlab and Simulink.

Actualmente las mujeres han obtenido una mayor aceptación en el ámbito escolar para el acceso a estudios de posgrado, en los cuales su presencia es evidente derivado del establecimiento de equidad de género se ha propiciado a una igualdad de oportunidades en diversos ámbitos. La presente investigación es cualitativa documental se basa en la lectura y recopilación de información en artículos científicos, revistas, portales electrónicos de diferentes organizaciones, todos relacionados con la participación de la mujer en la investigación desde la perspectiva de género.

El estrés académico y la ansiedad se presentan en todos los grados escolares, sin embargo, en universitarios su prevalencia suele ser mayor. Para caracterizar en estudiantes de psicología la prevalencia del estrés académico y ansiedad-rasgo, así como la posible relación entre estas dos variables, se realizó una investigación cuantitativa, transversal, descriptivo y correlacional en 152 universitarios mexicanos. Para la recolección de datos se aplicaron: la Escala Ansiedad Estado-Rasgo (IDARE) y el Cuestionario de Estrés Académico (CEA). Los resultados demuestran que, 104 (68.4%) de los participantes presentaron niveles de estrés académico en nivel moderado y 115 (75.7%) de ellos niveles altos de ansiedad-rasgo, igualmente se determinó una correlación positiva media entre las variables estudiadas (rs = 0.368, p< 0.01).