Doctor of Philosophy

dissertationThe purpose of this dissertation is to define how the pathways of apoptosis and extrusion connect. These studies employed MDCK and HBE in vitro cultured epithelia as model systems to explore the ability of different components of the apoptosis pathways to participate in the activation of the extrusion response. Because of the ease of their manipulation for genetic, pharmacological and cell biology analyses but most importantly because their ability to reproduce in vivo apoptotic cellular extrusion, cultured epithelia provide a powerful and efficient system to study and dissect the molecular basis of apoptotic cellular extrusion. In the first part of this dissertation, we established that both intrinsic and extrinsic apoptotic pathways activate cellular extrusion and that the contraction force that drives cellular extrusion requires caspase activity. Accordingly, we found that necrosis does not trigger the cellular extrusion response; nevertheless, necrotic cells are removed from epithelia by a passive mechanism that involves forces of the stochastic movement of epithelial cells. The second part of this dissertation is focused on the regulation of apoptotic cellular extrusion by the anti-apoptotic protein Bcl-2. Mutations that increase Bcl-2 protein levels result in resistance to cell death, which in turn lead to several malignances in the living organism. Here, as a way to complement our studies in the first part of this dissertation, iv we explore the effect of Bcl-2 on cell junctions, test the ability of HA14-1, a Bcl-2 inhibitor, to activate cell extrusion and finally we test the ability of this oncogene to regulate cellular extrusion in vivo. The studies reveal the connection between apoptosis and cellular extrusion: caspase activation, a conserved point in the apoptosis pathway where all known apoptotic signals converge. The discovery of the requirement of caspases for cellular extrusion reveals a new non-apoptotic role for caspases and sets caspase activity as an important checkpoint for epithelial cellular removal. These studies also reveal a new passive mechanism by which dead cells unable to trigger cellular extrusion are removed

Observations, analysis and interpretation with non-LTE of chromospheric structures of the Sun

This thesis is based on observations performed at the Vacuum Tower Telescope (Tenerife). We have used an infrared spectropolarimeter (TIP) and a Fabry-Perot spectrometer (G-FPI) from years 2004 to 2006. We have applied several imaging speckle reconstruction techniques, and compared them. We have studied chromospheric dynamics inside the solar disc and at the limb using H\alpha with very high spatial, spectral and temporal resolution. Keywords (see full abstract for details): fibrils, surge, MHD waves, speckle, blind deconvolution, Fabry-Perot, mini-flares, cloud model, spicules in Halpha, spicules continuing on the disc) Using He I 10830 we studied the offlimb spicular spectral I profiles with height over the limb. The analysis shows the variation of the off-limb emission profiles as a function of the distance to the visible solar limb. The intensity ratio of the multiplet (which is related to the optical thickness and coronal irradiation) is studied and compared with standard atmospheric models. We report observational properties from high-resolution filtergrams in the H$\alpha$ spectral line taken with the G-FPI. We find that spicules can reach heights of 8 Mm above the limb. We show that spicules outside the limb continue as dark fibrils inside the disc.Comment: PhD thesis. 107 pages. Source .tex files and images available at http://www.brunosan.e

Protection against herbivory in the mutualism between Pseudomyrmex dendroicus (Formicidae) and Triplaris americana (Polygonaceae)

Herbivory significantly impacts the growth and reproduction of plants. Many plants have developed ways to defend against herbivores and one common strategy is to associate with ants. In many ant-plant interactions, ants are known to protect their host. However, in the Neotropical ant-plant genus Triplaris, the benefits provided by associated ants have never been tested. Many Pseudomyrmex spp. ants are obligate inhabitants of Triplaris spp. trees. In this study, Triplaris americana was studied in association with Pseudomyrmex dendroicus, an ant highly specific to its host (it has not been collected from any other species of Triplaris). Ant exclusion experiments were carried out to assess the protective effect of ants. In addition, ant behavior was monitored in control plants to study the mechanisms by which ants might confer protection against herbivory. Ant removal led to a more than 15-fold increase in herbivory. Pseudomyrmex dendroicus are active at all times of day and night and aggressively and efficiently remove insect herbivores from their host. © 2016 Sanchez Adriana et al

CLUE: A Usability Evaluation Checklist for Multimodal Video Game Field Studies with Children Who Are Blind

Multimodal video games can enhance the cognitive skills of children who are blind by allowing interaction with scenarios that would be unfeasible in their everyday life. To assist the identification of relevant interface and interaction issues when children who are blind are playing multimodal video games, we propose a Checklist for Usability Evaluation of Multimodal Games for Children who are Blind (CLUE). CLUE was designed to assist researchers and practitioners in usability evaluation field studies, addressing multiple aspects of gameplay and multimodality, including audio, graphics, and haptics. Overall, initial evidence indicates that the use of CLUE during user observation helps to raise a greater number of relevant usability issues than other methods, such as interview and questionnaire. CLUE makes the analysis of recorded user interactions a less time- and effort-consuming process by guiding the identification of interaction patterns and usability issues

Diseño de un controlador PID difuso para la variable caudal, de la plataforma de entrenamiento para control de procesos continuos existente en la UPS, Sede Quito - Campus Sur

Through this technical project wants to help students and teachers the race of Electronic Engineering of the Salesian University, of Quito - South Campus to extend the acquired knowledge regarding the use of current industrial controls and sound management that should be used in industries where their processes work through complex industrial instruments which need better calibration and better maintenance to extend its life equipment and that the process does not stop in activity. A FUZZY PID control (Proportional-Integrative-Derivative) for the process flow, Platform Training Control Continuous Process is created, taking into account all the lessons taught by teachers of the career of Electronic Engineering, during the course of student life at the Polytechnic Salesian University of Quito-South Campus. The performance index of the integral absolute error (IAE) is used to compare the FUZZY PID controller for flow variable with a conventional PID controller for flow variable, also using the Wilcoxon test determined which of these two drivers better have energy efficiency, plus a technical manual is made for FUZZY PID control practices applied to the flow control variable.A través de este proyecto técnico se desea ayudar a los estudiantes y profesores de la Carrera de Ingeniería Electrónica de la Universidad Politécnica Salesiana, Sede Quito-Campus Sur a ampliar los conocimientos adquiridos respecto al uso de controles industriales actuales y al manejo adecuado que se debe tener de equipos usados en las industrias donde sus procesos funcionan mediante instrumentos industriales complejos los cuales necesitan una mejor calibración y un mejor mantenimiento para ampliar su vida útil y que no se detenga el proceso en actividad. Se crea un control PID (Proporcional-Integrador-Derivativo) difuso para el proceso de caudal, de la Plataforma de Entrenamiento para Control de Procesos Continuos, tomando en cuenta todas las enseñanzas impartidas por los docentes de la carrera de Ingeniería Electrónica, durante el transcurso de la vida estudiantil en la Universidad Politécnica Salesiana Sede Quito-Campus Sur. Se utiliza el índice de desempeño de la integral del error absoluto (IAE) para comparar el controlador PID difuso para la variable caudal con un controlador PID convencional para la variable caudal, además usando el test de Wilcoxon se determina cuál de estos dos controladores tiene mejor eficiencia de energía, además se efectúa un manual técnico para prácticas con control PID difuso aplicado al control de la variable caudal

Diseño hidráulico de losas en pavimento poroso rígido como estructuras complementarias al drenaje pluvial de Bogotá

Los pavimentos tradicionales, incrementan las áreas impermeables en la ciudad, ocasionando inundaciones y contaminaciones diferidas a los cuerpos acuáticos receptores. Como solución a estos problemas, los pavimentos porosos se han utilizado como una de las conocidas técnicas alternativas de drenaje. El objetivo de este trabajo de grado fue revisar y aplicar las metodologías de diseño hidráulico existentes para pavimentos porosos rígidos, para luego ser adaptadas a una zona de estudio específica (área de parqueadero de un establecimiento localizado en el noroccidente de Bogotá) utilizando los resultados obtenidos a través del método de validación propuesto para unos datos de precipitación de 3.5 años (2008-2011), con una resolución horaria, aplicado a una mezcla de concreto con propiedades hidráulicas y de envejecimiento conocidas. Los resultados obtenidos muestran que el método de la curva envolvente y el de los volúmenes son las metodologías mas apropiadas para el diseño de pavimentos porosos en el área de estudio para periodos de diseño de 2 y 3 años, respectivamente.Traditional pavements increase impervious surfaces on urban areas, causing flooding and pollution of receiving water bodies. As a solution, the pervious concrete pavements are used as one of the Sustainable Urban Drainage Systems (SUDS). The objective of this study is to review and apply existing hydraulic design methodologies for concrete pervious pavements, and then to adapt them to a specific study zone (parking area of an establishment located at the Northwest part of Bogota) by using simulation results obtained for a one-hour resolution rainfall data set on 3.5 years (2008-2011) applied to a mixture of pavement with known hydraulic and aging properties. The results obtained show that the Envelope Curve and the Volume Methods are the most appropriate ones for designing pervious pavements in the study area for 2-years and 3-years design periods, respectively.Ingeniero (a) CivilPregrad

Ising model with spins S=1/2 and 1 on directed and undirected Erd\"os-R\'enyi random graphs

Using Monte Carlo simulations we study the Ising model with spin S=1/2 and 1 on {\it directed} and {\it undirected} Erd\"os-R\'enyi (ER) random graphs, with $z$ neighbors for each spin. In the case with spin S=1/2, the {\it undirected} and {\it directed} ER graphs present a spontaneous magnetization in the universality class of mean field theory, where in both {\it directed} and {\it undirected} ER graphs the model presents a spontaneous magnetization at $p = z/N$ ($z=2, 3, ...,N$), but no spontaneous magnetization at $p = 1/N$ which is the percolation threshold. For both {\it directed} and {\it undirected} ER graphs with spin S=1 we find a first-order phase transition for z=4 and 9 neighbors.Comment: 11 pages, 8 figure

La eficiencia del uso del agua disminuye durante la senescencia de las hojas en otoño en tres especies de árboles de hoja caduca

During fall leaf senescence in deciduous species, photosynthesis nears completion due to chlorophyll breakdown and re-assimilation. However, several other processes such as leaf nutrient uptake, re-translocation, and storage, or tissue dehydration to avoid frost damage, may be important and dependent upon stomatal opening. We report here on measured changes in photosynthesis (A), leaf conductance to water vapor (g), and WUE (estimated by A/g) in three deciduous tree species (Acer saccharum, Cornus florida, and Ginkgo biloba) during the weeks of leaf senescence preceding abscission. Substantial decreases in A of 60 up to 80% were not matched quantitatively by similar declines in g (40 to 70%), resulting in corresponding decreases in WUE (estimated by A/g) from near 50% to over 300% among the three species. This shift to a lower WUE may reflect adaptive value in maintaining a higher g relative to A during the fall leaf senescence period

Análisis y comparación del sistema de enseñanza remoto vs el sistema tradicional. Caso de estudio: División de Ciencias Básicas e Ingeniería de la Universidad Autónoma Metropolitana Azcapotzalco

151 páginas. Maestría en Diseño y Visualización de la Información.El presente trabajo de investigación aborda una serie de datos alrededor de la educación en línea implementada mediante el Proyecto Emergente de Enseñanza Remota (PEER) en la Universidad Autónoma Metropolitana (UAM) Azcapotzalco, donde a través de la recolección, análisis y procesamiento de datos tanto cuantitativos como cualitativos se infiere la percepción que tiene la plantilla estudiantil a nivel licenciatura de la División de Ciencias Básicas e Ingeniería (CBI) sobre el grado de dificultad de las materias cursadas en ambas modalidades: presencial y en línea. Partiendo de la aplicación de la encuesta “Estudio comparativo entre la enseñanza escolarizada y la enseñanza remota en la División de CBI de la UAM - Azcapotzalco” a estudiantes de la División de CBI de la UAM Azcapotzalco se recoge que materias como Análisis y Diseño de Algoritmos o Ecuaciones Diferenciales Ordinarias, por citar algunas, presentan mayor potencial para ser impartidas en línea al ser percibidas como difíciles en la modalidad presencial pero fáciles durante el PEER. Caso contrario se da con materias como Cálculo Diferencial e Integral o Microprocesadores. Por otra parte, se confirma que aquellas materias relacionadas con los laboratorios y talleres fueron de las más afectadas durante la pandemia al ser percibidas como difíciles en línea. El análisis del panorama completo, que incluye dos afluentes de datos: la encuesta a estudiantes y una serie de indicadores de rendimiento provistos por la Secretaría Académica de la División, posibilita concluir que materias como Introducción al Álgebra Lineal, Métodos Numéricos en Ingeniería, Ecuaciones Diferenciales Ordinarias, Instrumentación Industrial, Sistemas Operativos y Teoría de Control, Introducción a la Física, entre otras, presentan rasgos aptos para su enseñanza en línea. Del mismo modo, existen materias que resultan más aptas para su impartición en un modelo presencial y que, con un análisis más profundo, pudieran modificarse y ser integradas a modalidades híbridas o virtuales. Estas conclusiones alrededor del fenómeno de la educación en línea en el marco del PEER en la División de CBI de la UAM Azcapotzalco posibilitan el modelado de los futuros posibles respecto a las modalidades educativas ofertadas en esta casa de estudios, ya sea de manera híbrida o totalmente en línea y no solo para futuras contingencias sino como parte de la evolución de la enseñanza y atención al contexto en que esta Institución de Educación Superior (IES) se enmarca