Sobre la influencia de la composición, concentración y adiciones en el comportamiento de flujo viscoso no-newtoniano de pastas de cemento volcánico andino

Fecha de lectura de Tesis Doctoral: 4 de diciembre de 2018.Estudio del comportamiento viscoso No-Newtoniano de pastas de cemento comerciales volcánicas andinas, sustituciones progresivas de cemento Portland puro por puzolana volcánica andina y pastas de cemento volcánicas andinas con adiciones de aditivos plastificantes. Además incluye el análisis de curvas de flujo estacionario que presentan comportamiento no monótono "pendiente negativa"

Three Essays on Economic Inequality

This PhD dissertation studies how market structures and economic incentives transform heterogeneity at agent levels into unequal economic outcomes. The first chapter studies the economic incentives that lead a country to specialise its production in specific segments of a supply chain, and how these incentives transform heterogeneity at the productivity level into wage differences between countries. This chapter presents an innovative framework that incorporates production networks to the Ricardian trade model. It describes the price formation mechanism that occurs along supply chains and how it induces countries to focus on the production of specific goods. Moreover, the model highlights the role of the network structure in the determination of prices, and uses it to explain how changes in the productivity of a country have consequences in the production decisions and wages of the other countries that produce goods in the supply chain. The second chapter studies the effects that the heterogeneity of income flows has over the implementation of collective agreements. Collective agreements are the primary mechanism by which communities cope with market failures. However, the lack of enforcement mechanisms generates coordination challenges. This chapter presents a theoretical framework that studies how inequality among individuals affects the participation incentives of the individuals and explains why agreements that balance the rent-seeking behaviour of wealthy individuals with the redistribution interests of the poor reduce the adverse effects of heterogeneity, and can even use it to create more robust agreements. The third chapter studies heterogeneity at the level of academic journals. This chapter models the interaction between authors and journals as a platform market and uses this model to explain how general interest journals compete against field-specific journals. The model provides new insights into the way in which general interest journals link the different publication incentives of journals across fields. The theoretical results explain why general interest journals tend to attract higher quality publications and how changes in the publication capacity of a journal, or the volume of research in a field, can affect the quality of ideas published in both field-specific and general interest journals. Finally, this chapter applies the previous theoretical results to understand how the Top 5 journals in economics obtained their central role, and how their influence has changed between 1980 and the present.Gates Cambridge Scholarshi

L’Antiquité en Basse-Normandie

Les travaux du projet collectif de recherche se sont conduits au sein d’ateliers thématiques – les limites des territoires antiques, les réseaux de communication, les agglomérations, les structures agraires, les lieux et pratiques religieuses, les sites funéraires – de manière diachronique, avec la prise en compte de la dimension paléoenvironnementale. Ces axes de recherches ont été accompagnés par la mise en place d’outils d’analyse et d’échange des informations (base de données, SIG, mise e..

Impact of the COVID-19 pandemic on emergency department CT for suspected diverticulitis: A natural experiment to explain patients’ and clinicians’ assessment of risk and willingness to undergo CT scanning? [preprint]

Purpose: This study examined the impact of the COVID-19 pandemic on emergency department CT use for acute non-traumatic abdominal pain, to better understand why imaging volume so drastically decreased during the COVID-19 pandemic. Methods: This was a retrospective review of emergency imaging volumes from January 5 to May 30, 2020. Weekly volume data were collected for total imaging studies, abdominopelvic CT, and abdominopelvic CTs positive for common causes of acute non-traumatic abdominal pain. Two emergency radiology attendings scored all diverticulitis cases independently and weekly volume data for uncomplicated and complicated diverticulitis cases was also collected. Volume data prior to and during the COVID-19 pandemic was compared, using 2019 volumes as a control. Results: During the COVID-19 pandemic, overall emergency imaging volume decreased 30% compared to 2019 (p = 0.002). While the number of emergency abdominopelvic CTs positive for appendicitis and small bowel obstruction did not significantly change during the COVID-19 pandemic, the number of cases of diverticulitis decreased significantly compared to 2019 (p = 0.001). This reduction can be specifically attributed to decreased uncomplicated diverticulitis cases, as the number of uncomplicated diverticulitis cases dropped significantly (p = 0.002) while there was no significant difference in the number of complicated diverticulitis cases (p = 0.09). Conclusions: Reduced emergency abdominopelvic CT volume during the COVID-19 pandemic can partially be explained by decreased imaging of lower acuity patients. This data may help formulate future strategies for imaging resource utilization with an improved understanding of the relationship between perceived imaging risk and symptom acuity

Educación Híbrida: una Experiencia de Vuelta al Aula

Desde febrero de 2020 la pandemia de COVID-19 se extendió por todo el planeta, impactando en todos los ámbitos de nuestra vida incluida la educación. Nos vimos forzados a renunciar a nuestras aulas físicas para dictar nuestras clases por videoconferencia. Este cambio tuvo distinto impacto dependiendo la forma en que cada docente venía dictando su materia. Luego de dos años la pandemia pasó y volvimos al aula pero de una forma distinta. El presente trabajo relata la experiencia de atravesar la pandemia y volver al aula en una materia de Ingeniería de Software dictada en la Universidad Nacional de Tres de Febrero. Junto con la experiencia se resumen una serie de aprendizajes obtenidos y un conjunto de reflexiones de cara al futuro

Desarrollo de un Juego Formativo para Aportar a la Concienciación en Ciberseguridad al Personal de la Escuela Militar de Aviación (Emavi) “Marco Fidel Suárez” de la Fuerza Aérea Colombiana en la ciudad de Cali.

En este artículo se presenta el resultado de un trabajo de grado de Ingeniería Informática de la Emavi. Este trabajo tiene tres finalidades: la primera, el desarrollo de un programa aplicando mejores prácticas por estudiantes de último grado de Ingeniera Informática; la segunda, usar soluciones TIC para la enseñanza en ciberseguridad o seguridad cibernética; tercera, aplicar una estrategia de capacitación motivadora en la temática de ciberseguridad (gamificación): juego formativo (serious game) como programa desarrollado para lograr sensibilizar al personal de Escuela Militar de Aviación (EMAVI) Marco Fidel Suárez - Fuerza Aérea Colombiana en la ciudad de Cali. Para elaborar el juego formativo se usaron diferentes lenguajes de programación web (HTML5, JavaScript, css y php), y se le integró una base de datos en mysql para que el juego fuese interactivo. El juego formativo fue diseñado para educar a diferentes usuarios. Se divide en varias interfaces: la primera, la entrada al juego, en la cual el sistema pide un usuario y una contraseña; la segunda, en la cual se explica la seguridad de la información, con lo cual se logra que el usuario construya conocimiento del objeto virtual de aprendizaje (Ova). La tercera interfaz es del juego tipo Quien quiere ser millonario, desde el cual se evaluará lo aprendido mediante unas preguntas aleatorias que arrojarán una calificación. La cuarta y final interfaz muestra los puntajes obtenidos. En el corto plazo, el grado de conocimiento de ciberseguridad del personal de Emavi será evaluado para saber si es posible aplicar un plan piloto de mediano plazo, en el cual se implemente dicha estrategia en CACOM 7, teniendo en cuenta los resultados arrojados en la primera fase de interacción. El aplicativo se cargó en la plataforma virtual de la institución, con lo cual se logró que el 60 % del personal lo usara y conociera tanto sus avances en conocimientos en ciberseguridad como consejos para minimizar los riesgos en seguridad de la información al usar tecnología

Cloud Atlas: Rotational Spectral Modulations and potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C

Measurements of photometric variability at different wavelengths provide insights into the vertical cloud structure of brown dwarfs and planetary-mass objects. In seven Hubble Space Telescope consecutive orbits, spanning $\sim$10 h of observing time}, we obtained time-resolved spectroscopy of the planetary-mass T8-dwarf Ross 458C using the near-infrared Wide Field Camera 3. We found spectrophotometric variability with a peak-to-peak signal of 2.62$\pm$0.02 % (in the 1.10-1.60~$\mu$m white light curve). Using three different methods, we estimated a rotational period of 6.75$\pm$1.58~h for the white light curve, and similar periods for narrow $J$- and $H$- band light curves. Sine wave fits to the narrow $J$- and $H$-band light curves suggest a tentative phase shift between the light curves with wavelength when we allow different periods between both light curves. If confirmed, this phase shift may be similar to the phase shift detected earlier for the T6.5 spectral type 2MASS J22282889-310262. We find that, in contrast with 2M2228, the variability of Ross~458C shows evidence for a {color trend} within the narrow $J$-band, but gray variations in the narrow $H$-band. The spectral time-resolved variability of Ross 458C might be potentially due to heterogeneous sulfide clouds in the atmosphere of the object. Our discovery extends the study of spectral modulations of condensate clouds to the coolest T dwarfs, planetary-mass companions.Comment: Accepted in ApJ

Cloud Atlas: Discovery of Rotational Spectral Modulations in a Low-mass, L-type Brown Dwarf Companion to a Star

Observations of rotational modulations of brown dwarfs and giant exoplanets allow the characterization of condensate cloud properties. As of now rotational spectral modulations have only been seen in three L-type brown dwarfs. We report here the discovery of rotational spectral modulations in LP261-75B, an L6-type intermediate surface gravity companion to an M4.5 star. As a part of the Cloud Atlas Treasury program we acquired time-resolved Wide Field Camera 3 grism spectroscopy (1.1--1.69~$\mu$m) of LP261-75B. We find gray spectral variations with the relative amplitude displaying only a weak wavelength dependence and no evidence for lower-amplitude modulations in the 1.4~$\mu$m water band than in the adjacent continuum. The likely rotational modulation period is 4.78$\pm$0.95 h, although the rotational phase is not well sampled. The minimum relative amplitude in the white light curve measured over the whole wavelength range is 2.41$\pm$0.14\%. We report an unusual light curve with seemingly three peaks approximately evenly distributed in rotational phase. The spectral modulations suggests that the upper atmosphere cloud properties in {LP261-75B} are similar to two other mid-L dwarfs of typical infrared colors, but differ from that of the extremely red L-dwarf WISE0047

Evaluación y corrección de la seguridad vial de la calle 10 y la cra 8 del municipio de Flandes Tolima

Realizar una evaluación de seguridad vial para cuantificar el riesgo de accidentalidad en LA CALLE 10 Y LA CRA 8 DEL MUNICIPIO DE FLANDES TOLIMA QUE ESTAN CONFORMADO POR EL BARRIOC CENTRO Y CAPILLALa alta taza de accidentalidad vial en Colombia se ha convertido en una problemática de salud pública, en donde el exceso de velocidad, ignorar normas de tránsito y conducir bajo efectos del alcohol son los principales factores causantes de muerte, y sin lugar a dudas la mitad de esas muertes afectan a los usuarios más vulnerables de las vías de tránsito, como son: motociclistas, peatones y ciclistas. En la presente monografía se expondrán de manera detallada los diagnósticos en seguridad vial y las correspondientes propuestas de elaboración del plan estratégico de la vía en el tramo estudiado sobre la calle 10 entre carreras 10 y 12 A, en el municipio de Girardot – Cundinamarca; todo esto basado en el plan estratégico de seguridad vial, creada mediante la ley 1503 del 2011 y reglamentada por el decreto 2851 de 2013, con el fin que las diferentes entidades públicas o privadas adopten de manera obligatoria mecanismos, estrategias y medidas para evitar y reducir la accidentalidad, asi como también la disminución en los efectos de accidentes de tránsito. El presente trabajo consta de dos partes iniciando por la recopilación de información obtenida por las entidades municipales de tránsito, seguido por el diagnóstico de seguridad vial con el alcance de una investigación preliminar del estado del tramo de vial de la calle 10 y la cra 8 del municipio de Flandes Tolima, proceso para el cual y durante el desarrollo del estudio se tiene en cuenta toda la información recopilada en la investigación, seguida de un trabajo de campo donde se analiza fallas que presenta la estructura del pavimento, ausencia de señalización y reductores de velocidad, acompañada de un registro fotográfico para posterior análisis de los resultados encontrados; procesos que finalmente y a partir de los análisis realizados generan la formulación de conclusiones y recomendaciones que ayudaran a tomar medidas preventivas para disminuir el riesgo de accidentalidad.The high rate of road accidents in Colombia has become a public health problem, where speeding, ignoring traffic regulations and driving under the influence of alcohol are the main factors causing death, and undoubtedly half of these deaths affect the most vulnerable users of traffic routes, such as: motorcyclists, pedestrians and cyclists. In this monograph, the road safety diagnoses and the corresponding proposals for the elaboration of the strategic plan of the road in the section studied on 10th street between races 10 and 12 A, in the municipality of Girardot - Cundinamarca will be exposed in detail; all this based on the strategic road safety plan, created by law 1503 of 2011 and regulated by decree 2851 of 2013, in order that the different public or private entities adopt compulsory mechanisms, strategies and measures to avoid and reduce the accident rate, as well as the decrease in the effects of traffic accidents. The present work consists of two parts beginning with the compilation of information obtained by the municipal traffic entities, followed by the diagnosis of road safety with the scope of a preliminary investigation of the state of the section of road in front of the University Minuto de Dios, process for which and during the development of the study, all the information collected in the research is taken into account, followed by a field work where failures are presented in the pavement structure, absence of signaling and speed reducers, accompanied by a record photographic for later analysis of the results found; processes that finally and from the analyzes carried out generate the formulation of conclusions and recommendations that will help to take preventive measures to reduce the risk of accidents

Corrigendum: p90RSK-MAGI1 Module Controls Endothelial Permeability by Post-translational Modifications of MAGI1 and Hippo Pathway.

[This corrects the article DOI: 10.3389/fcvm.2020.542485.]