New developments in the THz field for imaging applications

Con esta tesis se pretende avanzar en el desarrollo de la tecnología de terahercios (THz) dentro del campo de las aplicaciones de imagen. Actualmente, los THz se presentan como un rango frecuencial muy interesante para la obtención de imágenes, tal y como se ve reflejado en los numerosos trabajos presentes en la literatura. Por otro lado, aunque se han obtenido cuantiosas imágenes en este rango, aun no es posible identificar el material que compone la muestra. Es por esto que uno de los objetivos de esta tesis es completar las bases de datos de materiales existentes actualmente. Para ello, se han implementado diferentes sistemas que permiten la caracterización electromagnética de diferentes materiales en el rango de los THz.The aim of this thesis is to go a step forward in the use of terahertz (THz) technology within the field of imaging applications. Nowadays, THz radiation appears as a very interesting frequency range to obtain images, as related in the numerous publications. Conversely, although there are several examples of imaging in this range, it is still not possible to identify the material that it is imaged. That is why one of the objectives of this thesis will be to add new materials to the actual database. Thus, several systems have been implemented to characterize materials in the range of THz for this dissertation.Programa Oficial de Doctorado en Tecnologías de las Comunicaciones (RD 1393/2007)Komunikazioen Teknologietako Doktoretza Programa Ofiziala (ED 1393/2007

Solar neutrino detection

More than 40 years ago, neutrinos where conceived as a way to test the validity of the solar models which tell us that stars are powered by nuclear fusion reactions. The first measurement of the neutrino flux, in 1968 in the Homestake mine in South Dakota, detected only one third of the expected value, originating what has been known as the Solar Neutrino Problem. Different experiments were built in order to understand the origin of this discrepancy. Now we know that neutrinos undergo oscillation phenomenon changing their nature traveling from the core of the Sun to our detectors. In the work the 40 year long saga of the neutrino detection is presented; from the first proposals to test the solar models to last real time measurements of the low energy part of the neutrino spectrum.Comment: 8 pages, 5 figures. III School on Cosmic Rays and Astrophysics August 25 to September 5, 2008 Arequipa (Peru) AIP conference proceedin

Using three different approaches of OSL for the study of young fluvial sediments at the coastal plain of the Usumacinta–Grijalva River Basin, southern Mexico

We use three different approaches of optically stimulated luminescence (OSL) to study young fluvial sediments located at the main channels of one of the largest fluvial systems of North America: the Usumacinta–Grijalva. We use the pulsed photo-stimulated luminescence (PPSL) system also known as portable OSL reader, full OSL dating and profiling OSL dating in samples extracted from vertical sediment profiles (n = 9) of riverbanks to detect changes in depositional rates of sediments and to obtain the age of the deposits. The results of the PPSL system show that the luminescence signals of vertical sediment profiles highly scattered from the top to the bottom contrast with the luminescence pattern observed on well-reset sequences of fluvial deposits where luminescence increase from the top to the bottom of the profile. The profiling and full OSL ages yielded large uncertainty values on their ages. Based on the inconsistencies observed in both ages and luminescence patterns of profiles we suggest that these fluvial deposits were not fully reset during their transport. As an explanation, we propose that in the Usumacinta and Grijalva rivers the cyclonic storms during the wet season promote the entrainment of large volumes of sediments due to high-erosional episodes around the basin resulting from hyper-concentrated and turbid flows. We conclude that the PPSL, profiling and full OSL dating of sediments are useful tools to quantify and to assess the depositional patterns in fluvial settings during the Holocene. These techniques also can yield information about sites where increases in the sediment load of rivers may produce poorly resetting of grains affecting the results of OSL dating

When Convexity Helps Collapsing Complexes

This paper illustrates how convexity hypotheses help collapsing simplicial complexes. We first consider a collection of compact convex sets and show that the nerve of the collection is collapsible whenever the union of sets in the collection is convex. We apply this result to prove that the Delaunay complex of a finite point set is collapsible. We then consider a convex domain defined as the convex hull of a finite point set. We show that if the point set samples sufficiently densely the domain, then both the Cech complex and the Rips complex of the point set are collapsible for a well-chosen scale parameter. A key ingredient in our proofs consists in building a filtration by sweeping space with a growing sphere whose center has been fixed and studying events occurring through the filtration. Since the filtration mimics the sublevel sets of a Morse function with a single critical point, we anticipate this work to lay the foundations for a non-smooth, discrete Morse Theory

PROYECTO DE TERRITORIALIZACIÓN. SRIYT- UNCUYO

La Universidad es un organismo público que debe colaborar con el desarrollo de la sociedad que la sostiene. En este sentido, es nuestro deber consolidar la relación con la comunidad, con el objeto de dar respuestas concretas a las demandas, respuestas que no pueden ser acríticas. Por el contrario, deben ser el fruto de una profunda reflexión que tenga en cuenta realidades y potencialidades. El Proyecto de Territorialización cumple un rol central en la creación de un espacio de encuentro entre la Universidad Nacional de Cuyo, el Gobierno de Mendoza, los Municipios y las comunidades locales de toda la geografía provincial. Esta propuesta de una Universidad ‘asociada’ al desarrollo local, contribuye al objetivo de ampliar los niveles de democratización a través de la igualdad de oportunidades en el acceso a la educación universitaria1 y en la inclusión de los jóvenes provenientes de las zonas más alejadas al centro universitario. Por otro lado, implica trabajar junto al Gobierno y a los municipios en función de líneas prioritarias del desarrollo local, con el objetivo de disminuir los desequilibrios regionales y sociales”2. Contempla a la Universidad, como un actor particular más, dentro de la compleja red de propulsores y decisores que intervienen en las actividades académicas, con el objetivo de abrir el abanico de posibilidades formativas, respondiendo a las necesidades, en base a una planificación cuidadosa que tenga en cuenta las realidades sociales y productivas. En este marco, la Secretaría de Relaciones Institucionales y Territorialización, desarrolla diversas actividades en el territorio provincial que tienen como objetivo la inclusión social de las comunidades departamentales. Esto se concreta a través de acciones que garantizan la presencia física y virtual de la UNCuyo, atenuando el desarraigo de los jóvenes que egresan del nivel polimodal y contribuyendo a la formación de recursos humanos profesionales para el desarrollo estratégico local