Esquema de transmisión de información no ortogonal mediante transformadas Taylor-Fourier y Legendre-Fourier.

Lasseñalesortogonalessonampliamenteutilizadasenlosmodems(Modulator-Demodulador) de los sistemas de comunicaciones digitales para la generación y descomposición formas de onda portadoras de información. Particularmente, el esquema OFDM (Ortogonal Frequency Division Multiplexing) se basa en la modulación en paralelo de un conjunto de subportadoras sinusoidales ortogonales las cuales subdividen el canal de comunicaciones en un conjunto de subcanales independientes de banda angosta. Esta división permite la implementación eficiente del modem OFDM con procesamiento puramente digital mediante algoritmos DFT (Digital Fourier Transform), reduciendo así la complejidad inherente al uso de bancos deosciladores analógicos tanto en el transmisor y como en el receptor. La idea objetivo del presente trabajo es modelado, simulación computacional, evaluación de un esquema de modulación con funciones base noortogonales. Tales funciones corresponden a los elementos de los modelos de señal de las transformadas TF (Taylor-Fourier) y LF (Legendre Fourier), utilizados para análisis de señales de SEP (Sistemas Eléctricos de Potencia). Este par de modelos puede potencialmente expandir la base de señalización OFDM y permitir un incremento en la cantidad de información binaria transmitida dado que los modelos LF y TF pueden ser vistos como expansiones de la base DFT por medio un conjunto de funciones polinómicas (Términos Taylor o Polinomios de Legendre) a costa de una mayor sensibilidad al ruido. En la presente tesis se discuten primero los fundamentos de las expansiones en bases no ortogonales mediante el concepto de pares biortogonales. Esto incluyendo su implementación discreta por medio de la matriz pseudoinversa y resaltado el papel de la matriz gramiana en el problema de dependencia lineal y sensibilidad al ruido de la base no ortogonal. Luego son expuestos el par de modelos de señal TF & LF junto con sus características temporales y frecuenciales, así como la dependencia de su matriz gramiana con los parametros de diseño del par de modelos. Por último son evaluados los criterios de probabilidad de error en condiciones de ruido blanco, ancho espectral y magnitud de las variaciones de amplitud

Assessing the spatiotemporal patterns and impacts of droughts in the Orinoco river basin using earth observations data and surface observations

Droughts impact the water cycle, ecological balance, and socio-economic development in various regions around the world. The Orinoco River Basin is a region highly susceptible to droughts. The basin supports diverse ecosystems and supplies valuable resources to local communities. We assess the spatiotemporal patterns and impacts of droughts in the basin using remote sensing data and surface observations. We use monthly precipitation (P), air temperature near the surface (T2M), enhanced vegetation index (EVI) derived from Earth observations, and average daily flow (Q) data to quantify drought characteristics and impacts. We also investigated the association between drought and global warming by correlating the drought intensity and the percentage of dry area with sea surface temperature (SST) anomalies in the Pacific (Niño 3.4 index), Atlantic (North Atlantic Index [NATL]), and South Atlantic Index [SATL]) oceans. We evaluate the modulating effect of droughts on the hydrological regime of the most relevant tributaries by calculating the trend and significance of the regional standardized precipitation index (SPI) and percentage area affected by dry conditions. El Niño events worsen the region’s drought conditions (SPI vs. Niño 3.4 index, r = −0.221), while Atlantic SST variability has less influence on the basin’s precipitation regime (SPI vs. NATL and SATL, r = 0.117 and −0.045, respectively). We also found that long-term surface warming trends aggravate drought conditions (SPI vs. T2M anomalies, r = −0.473), but vegetation greenness increases despite high surface temperatures (SPI vs. EVI anomalies, r = 0.284). We emphasize the irregular spatial-temporal patterns of droughts in the region and their profound effects on the ecological flow of rivers during prolonged hydrological droughts. This approach provides crucial insights into potential implications for water availability, agricultural productivity, and overall ecosystem health. Our study underlines the urgent need for adaptive management strategies to mitigate the adverse effects of droughts on ecosystems and human populations. The insights derived from our study have practical implications for developing strategies to address the impacts of droughts and ensure the protection of this ecologically significant region

Síndrome de burnout y plenitud existencial en los docentes de El Progreso, Yoro

The purpose of this research was to analyze the relationship between burnout syndrome and existential fullness of secondary school teachers in El Progreso, Yoro; To achieve this, the prevalence of the syndrome was determined and comparisons of the levels of burnout and existential fullness were established between teachers in the public and private sectors; Likewise, it was investigated whether there was any relationship between both variables. It is concluded that burnout is present and that those over forty years of age, from both sectors, are the ones who are situated in a higher percentage at the low level on the existential fullness scale. On the other hand, it was not possible to statistically confirm a direct relationship between burnout syndrome and existential fulfillment. The research is quantitative and descriptive-correlational in scope. The data come from a sample of 202 teachers to whom the Maslach Burnout Questionnaire for Teachers (MBI-Ed) and the Längle Existential Scale were applied.Esta investigación tuvo como finalidad analizar la relación entre el síndrome de burnout y la plenitud existencial de los docentes de secundaria en El Progreso, Yoro; para lograrlo se determinó la prevalencia del síndrome y se establecieron comparaciones de los niveles de burnout y plenitud existencial entre los profesores del sector público y privado; asimismo se investigó si existía alguna relación entre ambas variables. Se concluye que el burnout está presente y que los mayores de cuarenta años, de ambos sectores, son quienes están situados en un mayor porcentaje en el nivel bajo en la escala de la plenitud existencial. Por otra parte, no fue posible confirmar estadísticamente una relación directa entre el síndrome de burnout y la plenitud existencial. La investigación es cuantitativa y de alcance descriptivo-correlacional. Los datos proceden de una muestra de 202 profesores a quienes se les aplicó el Cuestionario de Burnout de Maslach para Docentes (MBI-Ed) y la Escala Existencial de Längle

Implementación de secuencia didáctica como herramienta del proceso enseñanza aprendizaje en el muestreo de agua

En el presente trabajo se elaboró un manual de procedimientos para la instrucción del proceso de toma de agua de diferentes matrices con base a la serie de las normas ISO 5667 y un material audiovisual para la toma de muestras de agua, las cuales servirán para referencia del Laboratorio Fisicoquímico de Aguas de la Universidad de El Salvador. Para ello se tomó como referencia la norma ISO 5667 se establecen los principios generales que se deben aplicar en el diseño de programas de muestreo para los propósitos de control de calidad, garantía de calidad así como también identificación de fuentes de contaminación del agua; con base a todo esto, se vio la necesidad de elaborar herramientas didácticas que faciliten la transmisión de la información de una manera más interactiva, que demuestren las técnicas correctas de muestreo, preservación y manejo de muestras de agua en matrices como: aguas de lago, agua potable, agua de río, aguas residuales y aguas subterráneas. Cada uno de los videos se encuentran publicados en el canal de YouTube del Laboratorio Fisicoquímico de Aguas, que sean de fácil acceso al público y a su vez sirvan de referencia directa del laboratorio Fisicoquímico de Aguas de la Universidad de El Salvador, estas herramientas didácticas se elaboraron entre agosto del año 2020 y enero del año 2021. Se concluyó que a partir de las diferentes metodologías de enseñanza aprendizaje, se pudo determinar que la metodología basada en la demostración práctica fue la más factible para este trabajo de investigación permitiendo ejemplificar de forma clara y sencilla el proceso correcto para la toma de muestras de agua en diferentes matrices. Por lo que se recomienda utilizar las herramientas didácticas elaboradas como base para la instrucción de los procedimientos adecuados en la toma de muestras de agua en diferentes matrices

Chemical composition and in situ ruminal disappearance of sorghum silages grown in the mexican humid tropic

The purpose was to evaluate the chemical composition and in situ ruminal dry matter disappearance of four types of grain sorghum silages, one brown midrib sorghum (bmr) and, a corn silage, grown under rainfed conditions in a humid tropical region of Mexico. The crops were established at three sites. At harvest, three minisilos per treatment were filled with forage previously chopped. Minisilos opened at 55 days and samples of silage taken to dry and ground to 1 mm to determine the chemical composition and in situ ruminal dry matter disappearance. The crude protein was higher (p<0.05) in sorghum silages than corn silage. In sorghum silages, bmr sorghum had the lowest (p0.05) in ADF and ADL to corn silage. The degradation parameters (a, b, c ) was higher (p0.05) in bmr sorghum and corn silages. In the humid tropics, bmr sorghum silages are a good alternative to corn silage, especially in the dry season.The purpose was to evaluate the chemical composition and in situ ruminal dry matter disappearance of four types of grain sorghum silages, one brown midrib sorghum (bmr) and, a corn silage, grown under rainfed conditions in a humid tropical region of Mexico. The crops were established at three sites. At harvest, three minisilos per treatment were filled with forage previously chopped. Minisilos opened at 55 days and samples of silage taken to dry and ground to 1 mm to determine the chemical composition and in situ ruminal dry matter disappearance. The crude protein was higher (p<0.05) in sorghum silages than corn silage. In sorghum silages, bmr sorghum had the lowest (p0.05) in ADF and ADL to corn silage. The degradation parameters (a, b, c ) was higher (p0.05) in bmr sorghum and corn silages. In the humid tropics, bmr sorghum silages are a good alternative to corn silage, especially in the dry season. &nbsp

Metabolic regulation analysis of an ethanologenic Escherichia coli strain based on RT-PCR and enzymatic activities

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Treatment Outcomes and Prognostic Factors in Mexican Patients with Endometrial Carcinoma with Emphasis on Patients Receiving Radiotherapy after Surgery: An Institutional Perspective

Aim. To analyze the clinical characteristics and treatment outcomes in patients with endometrial carcinoma treated in a Latin American institute with emphasis in patients receiving adjuvant radiotherapy. Methods. A total of 412 patients with endometrial carcinoma admitted to our hospital between 1998 and 2008 were evaluated, retrospectively. The mean age was 55 years (28–87). Two hundred seventy patients received RT following surgery. Stage distribution was as follows: 221 patients (54%) stage I, 86 patients (21%) stage II, and 103 patients (24.5%) stage III and 2 patients (0.5%) stage IVA. Results. Overall survival rate was 95% at 2 years, 84% at 5 years, and 79% at 10 years. By the end of followup, 338 patients (82%) were disease-free, and 13 (3%) were alive with disease. Univariate and multivariate analyses identified age, grade, serosal and adnexial involvement as significant predictors for overall survival. Conclusion. The results of our study suggests that early-stage, low-grade endometrial cancer with no risk factors should not receive external beam radiotherapy, intermediate risk patients should receive only vaginal vault brachytherapy, and the use of chemotherapy with radiotherapy for patients high-risk and advanced-stage carcinoma the addition of radiotherapy is associated with a better survival being an effective therapeutic option

Thermal Diffusion and Specular Reflection, Monte Carlo-based Study on Human Skin via Pulsed Fiber Laser Energy

The aim of traditional Chinese medicine (TCM) in acupuncture is sometimes to restore and regulate energy balance by stimulating specific points along the specific meridians traced on the human body via different techniques such as mechanical pressure, moxibustion and others. Hence, physicians have struggled to improve treatment for common diseases such as migraine and headaches. Heat stimulation and some pharmacological effects from moxa have been attributed to the therapeutic efficacy of such techniques. As heat can diffuse through the tissue, skins temperature will rise in the surrounding tissue. In this work, heat diffusion on a simple, 5-layer model of human skin is presented. Based on this, and by using Monte Carlo techniques, a photon or a photon package is launched into the tissue for mimicking the propagation of such photons at two different wavelengths through the tissue. The method generally describes the scholastic nature of radiation interactions. Most of the laser energy is deposited within a volume which cross-sectional area is the size of the beam itself. As could be seen, in the epidermis layer of the model, the heat does not go deep and nearly all the heat diffusion occurs on the edges of the beam, causing losses. Heat dissipation occurs faster and goes down to 2°C in the adipose tissue since there is low water content in this region. On the contrary, there is a fast heat increase in the muscle layer, up to 6°C at the most superficial layer. Since melanin is the most important epidermal chromophore, it can be noted that light shows strong absorption via melanin, at 690nm laser wavelength. In the papillary dermis the heat decreases and spreads out to the surrounding tissue. Once it reaches the adipose tissue, the heat is not absorbed enough; therefore, it is transmitted into the muscle, where the temperature rise is higher and reaches nearly 40 °C. Finally, photodynamics in a simple 5-layer skin model were explored at two laser wavelengths: 690nm and 1069nm, where no thermal damage would be expected, given the energy level of the employed pulses. Such pulsed laser energy levels remain to be tested in living tissue

OUTPLACEMENT: THE CHALLENGE OF A REALITY IN THE MEXICAN ORGANIZATIONS

Since companies are the bases of the economy in Mexico, there is an increased interest on the part of the government to boost their growth through various programs, but the increased international competition, mergers, acquisitions and recurring economic crises, give rise to a social and economic phenomenon that is repeated on a daily basis: "unemployment". To offset this problem, it is necessary to implement Outplacement programs that Mexican companies can follow internally and a solid strategy for Corporate Social Responsibility (CSR), which would be designed to restrain the periods of work cutback and minimize the psychological and social impact on those affected. This article discusses the importance of challenging a reality related to Outplacement for Mexican companies, the importance of this phenomenon as part of CSR and some ideas for profit and steps to implement a program

Technology transfer offices as promoters of technology, innovation and regional development in mexico

Objective of the study: The main objective of this research work was to analyze the importance of a Technology Transfer Office (TTO) as an innovation promoter in regional development in Mexico. Methodology/Approach: An analysis bibliographic was used, application of surveys and generation of indexes. In 2014, a survey was applied to 131 TTOs to measure their impacts.Originality/Relevance: To perform this analysis, we used a self-generated indicator, an index that measures the degree of specialization by geographic region and economic sector, using indicators of regional agglomeration as a basis. The agglomeration model generated was composed of national patent applications, international patents, utility models, industrial designs, and trade secrets.Main results: The results by geographical area in Mexico, were the Northwest, specializing in aquaculture, fisheries, aeronautics and agriculture; the Northeast, in biotechnology, chemistry and metallurgy mechanics; the Center, in automobile, energy, and software; the West, in aerospace, automobile, chemistry and metallurgy mechanics; the Southeast, in food industry, construction, and mining.Theoretical/methodological contributions: We found that the specialization of the TTOs among the various productive sectors in Mexico has contributed to the highest rates of growth in patent registration in the Latin American region.Social/management contributions: Although contributions generated in protecting intellectual property at international level are still insufficient, we believe we are on the right track. At least Mexico started to generate the innovation ecosystem that other countries began four decades ago