Aspects of universal extra dimensional models and their latticized versions

In this work some aspects of models with universal extra dimensions are studied. In particular, in the case of models with one universal extra dimension their phenomenology is investigated and used to extract bounds on the size of the extra dimension. In addition, the phenomenology of their latticized counterparts is also investigated. The running of the gauge coupling constants in models with an arbitrary number of universal extra dimensions is revisited. The possible reliable determination of the power corrections that appear is studied. Finally, a model with one non-universal extra dimension is presented to compare the results in these kind of scenarios with the universal ones.Comment: Ph.D. Thesis, 94 page

Effect of the anodization voltage on the porewidening rate of nanoporous anodic alumina

A detailed study of the pore-widening rate of nanoporous anodic alumina layers as a function of the anodization voltage was carried out. The study focuses on samples produced under the same electrolyte and concentration but different anodization voltages within the self-ordering regime. By means of ellipsometry-based optical characterization, it is shown that in the porewidening process, the porosity increases at a faster rate for lower anodization voltages. This opens the possibility of obtaining three-dimensional nanostructured nanoporous anodic alumina with controlled thickness and refractive index of each layer, and with a refractive index difference of up to 0.24 between layers, for samples produced with oxalic acid electrolytes

On some local cohomology spectral sequences

We introduce a formalism to produce several families of spectral sequences involving the derived functors of the limit and colimit functors over a finite partially ordered set. The first type of spectral sequences involves the left derived functors of the colimit of the direct system that we obtain applying a family of functors to a single module. For the second type we follow a completely different strategy as we start with the inverse system that we obtain by applying a covariant functor to an inverse system. The spectral sequences involve the right derived functors of the corresponding limit. We also have a version for contravariant functors. In all the introduced spectral sequences we provide sufficient conditions to ensure their degeneration at their second page. As a consequence we obtain some decomposition theorems that greatly generalize the well-known decomposition formula for local cohomology modules given by Hochster.Comment: 63 pages, comments are welcome. To appear in International Mathematics Research Notice

Assessing the overall perceived quality of the undergraduate students

Purpose - The paper is twofold aimed: (i) defining and validating a scale to assess the quality of the university experienced by students and (ii) analyzing the role of the aforementioned di- mensions and their impact on students’ satisfaction. Methodology/Approach - A survey of 2,557 undergraduate students that finished their degrees in 2013 at universities located in the region of Catalonia has been analyzed using Structural Equation Modeling (SEM). An exploratory analysis suggests the final dimensions that were confirmed in a confirmatory analysis. The psychometric characteristics of the scale are provided to show reliability and validity of the constructs. An extra model (also using SEM) assesses the impact of these dimensions on overall satisfac- tion. Findings - The quality is a multifactor construct composed by: (i) “syllabus”, which refers to the quality of the learning methods and the coordination efforts through the whole study period; (ii) “skills development”, referring to the skills that students might acquire along their studies and (iii) “services and facilities” of the university. Moreover, the first and third factors act as “enablers” for the second factor one. Nevertheless, only “Syllabus” dimension affects significantly on students’ satisfaction, whereas “services and facilities” do not have a significant role, although they are necessary in order to provide a good service. Research Limitation/implication - Although the sample is large enough to draw robust re- sults, it is limited the Catalonia. The paper provides recommendations for university managers and public administration authorities in order to allocate the available resources. Originality/Value of paper - In an era of global competition, universities are trying to adapt to these new requirements by expanding they academic offer, introducing innovative teaching methods, providing teaching resources to lecturers, and updating the general services of the university among others. All these services will be considered when students evaluate their experience at the university. The paper contributes with an assessment scale for the holistic service provided by the university within the period that the student is in the university. These findings can be applied to help define attractive academic programs and provide useful insights on how the supporting facilities should be designed to allow students take advantage of their learning process at universities.Postprint (published version