Exact results in QFT: Minimal Areas and Maximal Couplings

This thesis is devoted to a two-pronged study of non-perturbative quantum field theory. In Part I we focus on the four-dimensional super conformal $\mathcal{N}=4$ Yang Mills theory. We compute smooth Wilson loops and correlation functions in the strong-coupling regime of the theory using the classical integrability of the dual string theory as our main tool. In both cases the solution is given as a set of integral equations of thermodynamic bethe ansatz type. The correlation function and Wilson loop are then written in terms of the corresponding TBA free energy. The equations for the Wilson loop expectation value can be used for generic smooth contours embeddable in an $\mathbb{R}^{1,1}$ subspace of $\mathbb{R}^{1,3}$. In Part II we ask general questions about the allowed space of massive quantum field theories based only on crossing symmetry and unitarity. We approach this question in two ways. First we consider putting massive QFT into an AdS box and study the conformal boundary theory using standard conformal bootstrap tools. We call this procedure the {\it boundary bootstrap}. It is applicable in any dimension but takes its simplest form for a $1+1$ dimensional bulk QFT where we use it to obtain rigorous bounds on allowed QFT couplings. For $1+1$ dimensional QFT we are also able to obtain rigorous bounds directly in flat space using unitarity, crossing symmetry and analyticity of the S-matrix. The bounds obtained in this way agree perfectly with those obtained from the boundary bootstrap

Pairings in a Ring Spectrum-Based Bousfield-Kan Spectral Sequence

Bousfield and Kan traditionally formulated their homotopy spectral sequence over a simplicial set X resolved with respect to a ring R. By considering an adequate category of ring spectra, one can take a ring spectrum E, create from it a functor of a triple on the category of simplicial sets, and build a cosimplicial simplicial set EX. The homotopy spectral sequence can then be formed over such cosimplicial spaces by a similar construction to the original. Pairings can be established on these spectral sequences, and, for nice enough spaces, these pairings on the E2-terms coincide with certain pairings on Ext groups

Detección automática de problemas de accesibilidad a partir de eventos de interacción de usuario

Actualmente muchas de las actividades de nuestra vida cotidiana se encuentran integradas en una aplicación web. Toda la información de los hechos que acontecen en el mundo está a un simple clic, por eso es de suma importancia lograr que una gran parte de la sociedad tenga la posibilidad de acceder al contenido presente en la web. Aquí es donde la accesibilidad web se convierte en un recurso fundamental para combatir con la famosa brecha digital y permitir que el contenido web sea accesible a la mayor cantidad de personas posibles. Para brindar accesibilidad en un sitio web, es muy importante integrarla al proceso de desarrollo. Para facilitar esta integración y a la detección de problemas de accesibilidad, en esta tesina se desarrolló una herramienta automática para la detección y reporte de este tipo de problemas.Facultad de Informátic

Sistema operativo Android: características y funcionalidad para dispositivos móviles

En la actualidad la masificación y constante crecimiento de la tecnología para dispositivos móviles, ha generando la necesidad de desarrollar sistemas operativos independientes con capacidad de procesamiento de información, conexión constante con la web y el poder para personalizar cada uno de ellos acomodándose así a los gustos de sus usuarios. Dada la creación de tecnologías que resuelven ciertas necesidades, se han dispuesto al mercado dispositivos móviles con sistemas operativos (SO) como lo son: Android, iOS, Windows mobile, Blackberry, etc. Teniendo en cuenta que Android es un sistema operativo libre, se puede aprovechar para el desarrollo de software en dispositivos móviles, permitiendo así una apropiación completa de esta tecnología. En otros sistemas operativos el desarrollo o programación de aplicaciones se limita a aquello que el desarrollador del Sistema Operativo permite, al igual que la modificación del mismo se encuentra limitada bajo sus parámetros. Dada la amplia adopción de Android por parte de los fabricantes de dispositivos móviles (Smartphones y Tablets), y a la poca documentación existente y accesible para los desarrolladores de software en la región del eje cafetero, se visualiza con esta investigación un medio que facilite el estudio del SO Android desde una perspectiva académica. Teniendo en cuenta el ritmo de crecimiento que ha mostrado este SO, es importante conocer en detalle su arquitectura y su funcionamiento con el fin de motivar su posterior apropiación en la investigación y desarrollo de proyectos en la región

Tension in secretory granule membranes causes extensive membrane transfer through the exocytotic fusion pore

or fusion to occur the repulsive forces between two interacting phospholipid bilayers must be reduced. In model systems, this can be achieved by increasing the surface tension of at least one of the membranes. However, there has so far been no evidence that the secretory granule membrane is under tension. We have been studying exocytosis by using the patch-clamp technique to measure the surface area of the plasma membrane of degranulating mast cells. When a secretory granule fuses with the plasma membrane there is a step increase in the cell surface area. Some fusion events are reversible, in which case we have found that the backstep is larger than the initial step, indicating that there is a net decrease in the area of the plasma membrane. The decrease has the following properties: (i) the magnitude is strongly dependent on the lifetime of the fusion event and can be extensive, representing as much as 40% of the initial granule surface area; (ii) the rate of decrease is independent of granule size; and (iii) the decrease is not dependent on swelling of the secretory granule matrix. We conclude that the granule membrane is under tension and that this tension causes a net transfer of membrane from the plasma membrane to the secretory granule, while they are connected by the fusion pore. The high membrane tension in the secretory granule may be the critical stress necessary for bringing about exocytotic fusion.National Institutes of Health GM-3885

The Omaha Site: Migrant Civil Society Under Construction Series on Latino Immigrant Civic Engagement

Omaha was one of nine cities in the United States chosen by the Woodrow Wilson Center for International Scholars to explore immigrant civic and political participation. Lourdes Gouveia and the OLLAS team, along with Sergio Sosa of the Heartland Workers Center, produced this bilingual report based on interviews and a round table with broad-based participation by the immigrant and Latino community. Omaha es una de las nueve ciudades en los Estados Unidos que fué escogida por el Centro Internacional Woodrow Wilson para Académicos con el fin de examinar la participación cívica y política de los migrantes. Lourdes Gouveia con el equipo de OLLAS y Sergio Sosa del Centro Laboral, produjeron este informe bilingüe basado en entrevistas y una mesa redonda con una amplia participación de la comunidad migrante y Latina

The S-matrix bootstrap. Part I : QFT in AdS.

We propose a strategy to study massive Quantum Field Theory (QFT) using conformal bootstrap methods. The idea is to consider QFT in hyperbolic space and study correlation functions of its boundary operators. We show that these are solutions of the crossing equations in one lower dimension. By sending the curvature radius of the background hyperbolic space to infinity we expect to recover flat-space physics. We explain that this regime corresponds to large scaling dimensions of the boundary operators, and discuss how to obtain the flat-space scattering amplitudes from the corresponding limit of the boundary correlators. We implement this strategy to obtain universal bounds on the strength of cubic couplings in 2D flat-space QFTs using 1D conformal bootstrap techniques. Our numerical results match precisely the analytic bounds obtained in our companion paper using S-matrix bootstrap techniques