Correcciones troposféricas en interferometría SAR

La atmósfera es uno de los medios que se interpone a las señales electromagnéticas provenientes de los satélites que orbitan y los receptores ubicados en la Tierra. Al atravesarla, la señal sufre distintas perturbaciones que introducen ruido y afectan la información final. Uno de los principales causales de este fenómeno es el vapor de agua (Integrated Water Vapour - IWV), cuya alta variabilidad espacio-temporal, dificulta su caracterización. Las imágenes de Radar de Apertura Sintética (SAR) se forman por medio de la recepción del eco retrodispersado de la señal electromagnética que emiten estos sensores. Por medio del cálculo de las diferencias de fase (de la señal) entre dos imágenes SAR de fechas distintas, es posible determinar deformaciones en la superficie terrestre en el orden de los pocos centímetros y con precisiones milimétricas (técnica denominada Interferometría Diferencial SAR, o DInSAR). Si durante la adquisición de las imágenes la señal atraviesa masas de IWV, la velocidad de propagación se verá afectada y los resultados no mostrarán la magnitud real de las deformaciones que se pudieran haber generado en el terreno. Este trabajo de investigación tiene por objetivo corregir el ruido troposférico en interferometría diferencial SAR por medio de la herramienta TRAIN (Toolbox for Reducing Atmospheric InSAR Noise) con datos provenientes de radiosondeos, espectrómetros, modelos atmosféricos globales y modelos de predicción meteorológicos

Sismos en Ridgecrest, California. Cálculo de desplazamientos sísmicos mediante GNSS y su comparación con instrumentos sismológicos

El estudio de los sismos de Ridgecrest California (EEUU), es una evidencia de la viabilidad y utilidad de las estaciones GNSS (Global Navegation Satellite Systems) como herramienta de monitoreo. Los satélites GNSS emiten señales de microondas que se registran mediante antenas y receptores terrestres, y se pueden utilizar para obtener la posición de la antena. Si la antena se mueve, como lo haría durante un terremoto, los cambios de posición se pueden calcular para obtener sismogramas de desplazamiento. Las formas de onda de desplazamiento GNSS tienen precisión a nivel de centímetros y, por lo tanto, son las más útiles como instrumento de registro del movimiento del suelo durante grandes eventos. Complementan a los instrumentos que registran movimientos intensos (strong motion) porque son un sistema de medición no inercial y no sufren las compensaciones de la línea de base que se encuentran tradicionalmente en los acelerogramas

Sismos en Ridgecrest, California. Cálculo de desplazamientos sísmicos mediante GNSS y su comparación con instrumentos sismológicos

Comunicación científica en formato E-PÓSTER, realizada en las III Jornadas Internacionales de Investigación, Ciencia y Universidad y las XII Jornadas de Investigación UMaza, en el Bloque de comunicaciones científicas: "CIENCIAS DE LA TIERRA", el mismo fue moderado por el Lic. HÉCTOR CISNERO. Las jornadas se llevaron adelante desde 19 al 23 de octubre del 2020 en formato totalmente virtual bajo plataforma Zoom y fueron transmitidas por el canal YouTube de la UMaza y el Facebook del Área de Ciencia y Técnica UMaza (Somos Ciencia y Técnica UMaza)

Análisis meteorológico regional, influencia del fenómeno «El Niño y La Niña». Anomalías de humedad ¿Pandemia o coincidencia?

El ciclo conocido como «El Niño» y su fase opuesta «La Niña» son una de las causas de mayor señal de variabilidad climática global. Por lo que resulta de gran interés su estudio, sobre todo cuando se parte de técnicas de monitoreo de variables meteorológicas de cobertura global o regional y continua. Los episodios de «El Niño» tienden a presentar condiciones más húmedas de lo normal, durante diciembre a febrero (DJF) al noroeste de Perú, sur de Brasil, centro de Argentina y durante junio a agosto (JJA) en el centro de Chile. El Niño también contribuye a cambios de temperatura a gran escala en todo el mundo. Se observan condiciones anormalmente cálidas durante DJF, en el sureste de Brasil. De igual manera durante JJA a lo largo de la costa occidental de América del Sur y el sureste de Brasil

An entropy test for single-locus genetic association analysis

<p>Abstract</p> <p>Background</p> <p>The etiology of complex diseases is due to the combination of genetic and environmental factors, usually many of them, and each with a small effect. The identification of these small-effect contributing factors is still a demanding task. Clearly, there is a need for more powerful tests of genetic association, and especially for the identification of rare effects</p> <p>Results</p> <p>We introduce a new genetic association test based on symbolic dynamics and symbolic entropy. Using a freely available software, we have applied this entropy test, and a conventional test, to simulated and real datasets, to illustrate the method and estimate type I error and power. We have also compared this new entropy test to the Fisher exact test for assessment of association with low-frequency SNPs. The entropy test is generally more powerful than the conventional test, and can be significantly more powerful when the genotypic test is applied to low allele-frequency markers. We have also shown that both the Fisher and Entropy methods are optimal to test for association with low-frequency SNPs (MAF around 1-5%), and both are conservative for very rare SNPs (MAF<1%)</p> <p>Conclusions</p> <p>We have developed a new, simple, consistent and powerful test to detect genetic association of biallelic/SNP markers in case-control data, by using symbolic dynamics and symbolic entropy as a measure of gene dependence. We also provide a standard asymptotic distribution of this test statistic. Given that the test is based on entropy measures, it avoids smoothed nonparametric estimation. The entropy test is generally as good or even more powerful than the conventional and Fisher tests. Furthermore, the entropy test is more computationally efficient than the Fisher's Exact test, especially for large number of markers. Therefore, this entropy-based test has the advantage of being optimal for most SNPs, regardless of their allele frequency (Minor Allele Frequency (MAF) between 1-50%). This property is quite beneficial, since many researchers tend to discard low allele-frequency SNPs from their analysis. Now they can apply the same statistical test of association to all SNPs in a single analysis., which can be especially helpful to detect rare effects.</p

Genetic Structure of the Spanish Population

<p>Abstract</p> <p>Background</p> <p>Genetic admixture is a common caveat for genetic association analysis. Therefore, it is important to characterize the genetic structure of the population under study to control for this kind of potential bias.</p> <p>Results</p> <p>In this study we have sampled over 800 unrelated individuals from the population of Spain, and have genotyped them with a genome-wide coverage. We have carried out linkage disequilibrium, haplotype, population structure and copy-number variation (CNV) analyses, and have compared these estimates of the Spanish population with existing data from similar efforts.</p> <p>Conclusions</p> <p>In general, the Spanish population is similar to the Western and Northern Europeans, but has a more diverse haplotypic structure. Moreover, the Spanish population is also largely homogeneous within itself, although patterns of micro-structure may be able to predict locations of origin from distant regions. Finally, we also present the first characterization of a CNV map of the Spanish population. These results and original data are made available to the scientific community.</p

Análisis Del Estrés Laboral Y Su Repercusión En La Salud Física Y Mental En Operadores De Tracto Camión

The Work stress (WS) is one of the leading causes of deterioration of physical and psychological well-being within organizations. In this research the multivariate dependence of some signs and symptoms of work-related illness was analyzed and calculated. A cross-sectional and descriptive study of a base of logistic operations of fleet dedicated to the transportation of beer in the center of the state of Veracruz was carried out. The population studied was 230 operators. Only male operators, active within the company, were included and operators who at the time of the study were under medical and vacation disability were excluded. The multivariate Pearson correlation was used to validate the research questions and chi-square to calculate the dependence of variables. As a result, we obtained five variables taken from two in two that were dependent on each other. We conclude that there is a healthy relationship between the observed variables, which are listed in order of pathological impact and their physiological reexaminations in the organism. The pressure within work caused by job stress represents a potent source of mental illness such as depression

Estudio De Los Proyectos De Residencia Profesional Como Generadores De Productividad Y Cambio Organizacional

Professional residency projects (PRP) have the theoretical knowledge and skills of the professional discipline of the students who develop them. Each professional residency project provides companies with viable opportunities and solutions that contribute to productivity. We sought to identify the influence between the application of the PRP and the changes in effectiveness and efficiency. This application affects the internal control and generates an organizational change. This paper analyzed some effects of the PRP through a descriptive and documentary study. The data collection instrument was validated through the Pearson correlation. The dependence between PRPs and the generation of productivity, change in internal control was calculated. The results obtained were generated with the chi-square statistical independence test. This test showed four variables that are more dependent on each other. The theoretical square chi of a pair of variables was graphed and the theoretical inverse function: p-value vs. square chi of 1 degree of freedom to observe the intersection. In conclusion, it was observed that the projects of professional residency influence in the internal control and the productivity of the companies via efficacy-efficiency

Innovaciones y mejoras en el proyecto tutoría entre compañeros. Curso 2015-2016

Memoria ID-0137. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2015-2016

Influence of rubber on the curing kinetics of DGEBA epoxy and the effect on the morphology and hardness of the composites

The influence of the end groups of two liquid rubbers on curing kinetics, morphology, and hardness behavior of diglycidyl ether of bisphenol-A based epoxy resin (DGEBA) has been studied. The rubbers are silyl-dihydroxy terminated (PDMS-co-DPS-OH) and silyl-diglycidyl ether terminated (PDMS-DGE). Crosslinking reactions, investigated by shear rheometry, ranged 90-110 °C, using a constant concentration (5 phr) of liquid rubbers and 1,2-Diamino cyclohexane (1,2-DCH) as hardener agent. The gel time, t gel, of the neat epoxy significantly decreased when adding the elastomers, more so for the silyl-dihydroxy terminated elastomer; at 110 °C the reaction was nearly complete before rheological test started. The results suggest that the elastomers induced a catalytic effect on the curing reaction. Scanning electron microscopy revealed phase separation of the elastomer during the curing reaction with rubber domains about 5 μm size. However, the DGEBA/dihydroxy terminated elastomer composite cured at 110 °C exhibited a homogenous morphology, that is, the rapid reaction time would not allow for phase separation. Water contact angle tests evidenced either more hydrophilic (silyl-diglycidyl ether terminated rubber) or more hydrophobic (silyl-dihydroxy terminated rubber) behavior than the neat epoxy. The latter effect is attributed to the presence of aromatic rings in the backbone structure of PDMS-co-DPS-OH. Microindentation measurements show that the elastomers significantly reduced the hardness of the epoxy resin, the DGEBA/ether terminated composite exhibiting the lowest hardness values. Moreover, hardness increased as reaction temperature did, correlating with a reduction of microdomains size thus enabling the tuning of mechanical properties with reaction temperature. © 2014 Springer-Verlag Berlin Heidelberg.C. Valerio-Cardenas was supported by a postdoctoral fellowship from DGAPA– UNAM. This research was financially supported by PAPIIT (IG101313) and CONACyT, program CB- 2011 (Grant 168095). A. E. G. is grateful to DGAPA-UNAM (PAPIIT Project IN-106008) for partial support. One of the authors (AF) wishes to thank the MICINN (Ministerio de Ciencia e Innovación), Spain, for financial support of the research (Grant FIS2010-18069).Peer Reviewe