PHYSICS, 4

Author: PEREZTOL VALDES OSVALDO EVELIO.
Year: 2006.
University: AUTÓNOMA DE BARCELONA.
Place of defense: Hospital Universitari Vall dHebron-Barcelona.
Place of preparation: SERVICIO CARDIOLOGIA NUCLEAR HOSP. VALL DHEBRON Y DPTO FISICA UNIVERSIDAD AUTONOMA BARCELONA.

Author: Lope Piedrafita Silvia.
Year: 2006.
University: AUTÓNOMA DE BARCELONA.
Place of defense: Departamento de Fisica.
Place of preparation: Universidad Autonoma de Barcelona.

Summary: The MRI heavy diffusion (DWMRI) is a novel technique of MRI to measure the movement of water in vivo translation of a non-invasive. Because the movement of water is sensitive to the environment cellular tissue, DWMRI has become a medical imaging technique useful for the diagnosis of disease, monitor the progression of disease, as well as for monitoring of response to therapies. Furthermore, the use of the image by the diffusion tensor (DTI), an extension of the technique DWMRI provides information on the anisotropy (or lack of same) of the movement of water in the tissues. Some tissue, such as the white substance in the brain, usually taught high anisotropy to the movement of water. In these cases, DTI can be used to measure, quantitatively, the integrity of tissues that could be affected by any neurological disease. In the images obtained by DWMRI and DTI, artifacts caused by movements are a significant problem, particularly in high-resolution studies in animals where the control is moving more complicated. In this regard, the radial MRI techniques have proved to be less sensitive to the movement that standard methods of MRI Cartesian. The main objective of the work presented here is the implementation of a sequence of spin-heavy radio broadcaster in a scanner for high-field MRI pre-clínico of optimization as well as for imaging the brain tensor diffusion of high-resolution small animals. For the technical validity, this research has been successfully applied in three new studies. First, it has been applied to study a model of glioma in rat brain. Likewise, we have developed and implemented protocols DTI in a mouse model with a disorder demielinación (disease Niemann-Pick type C) to determine the anisotropy in the diffusion of water in brain tissue is affected by the disease . Finally, these techniques have been applied to investigate in a non-invasive morphology of cells cultured in a bio-reactor fiber hollow.

Author: MACIA JUAN OSCAR.
Year: 2006.
University: VALENCIA.
Place of defense: FACULTAD DE FISICA.
Place of preparation: FACULTAD DE FISICA.

Summary: In this thesis we present first, a study of certain techniques algebráicas and its application to field supersymmetric theories. Next, we investigate the mathematical structure of geometry Kähleriana particular geometry of the moduli space of multiplets in scalar vector supergravity N = 2 in 4 dimensions. We study the deformation of Moyal-Weyl of superespacio widespread, initially super Poisson brackets to be supersimétricos (using derivatives supercovariantes and supercargas) and then generalizamos the flagship product of Moyal-Weyl to admit bivectores Poisson odd. This leads to a model of Wess-Zumino deformed. We also investigate how contractions of Lie algebras (Inönü-Wigner and Weimar-Woods) can introudcirse in nonlinear sigma models resulting in deformed metric for new varieties scalar. It shows that these contractions can be interpreted as truncaciones or integration of modes mass on the edge of large masses. In the second part, devoted to the geometry Kähleriana particular, we investigate their structure in a mathematical formulation independent coordinates, and finally express the results in a coordinated language for clarity and to make the necessary connection between the language used by mathematicians and used for physicists. We conducted a detailed study of the case Pseudo-Riemanniano, which is the most relevant in the case design because it was related to the theory of supergravity. However the plantemiento concept is púramente geometric and our definitions do not depend so algungo of supersymmetry. Finally we study properties of some theories with geometry Kähleriana especially when real coordinates are taken (in opposition to the usually empleads coordinates special complex). We obtain explicit formulas for the metric Kählerianas special (in the case rigid / related as in the design) coordinates in real Darboux.

Author: Brégains Rodríguez Julio Claudio.
Year: 2006.
University: SANTIAGO DE COMPOSTELA.
Place of defense: Facultad de Física.
Place of preparation: Facultad de Física.

Summary: The thesis work encompasses analysis, synthesis and design of various types of antennas. It is organized as follows: The first two chapters are devoted to presenting the foundations upon which the work performed by the author at the stage of the Third Cycle. In Chapter 3 describes the analytical work that has been applied to various geometries, continuous discrete. In Chapter 4 summarizes several diagrams generated by continuous sources for isotropic clusters of dipoles, patch or radial lines. Chapter 5 is devoted to two control processes based on the one hand, in a technical implementation of artificial neural networks to a flat grouping of elements, and, in a temporal modulation technique applied to a group of linear dipoles parallel. In Chapter 6 presents the design processes, separated into stages, several models of antennas capable of generating diagrams toroidal, working at frequencies typical wireless communications. Finally, Chapter 7 contains a general summary and the conclusions of the thesis.

Author: MARTÍNEZ MARTÍNEZ JUAN ANTONIO.
Year: 2006.
University: MURCIA.
Place of defense: FACULTAD DE MATEMÁTICAS.
Place of preparation: FACULTAD DE MATEMÁTICAS.

Summary: According to the title of this thesis, the general policy objective is to analyze the role of variation of the waveform in controlling chaos, through periodic excitation. To this end, regular forces will be used with variable waveforms (mostly given by Jacobi elliptic functions) implemented on systems well known in physics (Helmholtz oscillators, Thompson and Duffing, and the ubícuo pendulum). Essentially, it will be dealt with the problem of chaotic escape, except in the latter case of the pendulum. Chapter 1 includes a brief historical review of the Chaos Theory, as well as a series of definitions that will be needed for the further development of this work. This section briefly describes the method Melnikov, including a number of examples of cases where it is being used successfully) and the Application of Poincaré. In closing, Make a basic introduction to the problem of exhaust chaotic, backbone of this study. In Chapter 2, based on a study done previously, it will check the robustness of the exhaust removal of a bidirectional chaotic pit potential Duffing, adding a weak disturbance type parametric, according to the procedure outlined therein. To this is added a noise and then a Gaussian excitation aperiodic, noting how, even in such situations, still met the theoretical predictions. In Chapter 3 will analyze control exhaust chaotic in the Helmholtz oscillator using a parametric excitation frequency immeasurable respect to inducing. It will use a rational approximation between the two frequencies, which tends to limit this relationship (in this case, we have chosen the right relationship as immeasurable aurea). Chapter 4 dealing with the same oscillator Helmholtz seen in the previous chapter, but in this case will explore the effect of waveform suppressor when it varies from a sinusoidal signal to a square wave, on an ongoing basis, through the use of functions Jacobi elliptic. The results were tested for extreme cases (sine wave and square wave) with those obtained specifically for them. Continuing with the study of the influence of the waveform in controlling exhaust chaotic, in Chapter 5 will study its effect on increasing exhaust chaotic. In this case, interested analyze how a situation can be obtained for maximum exhaust chaotic (intensification) varying the shape of the wave exciting (now use a combination of the Jacobi elliptic functions and dn sn). The oscillator used in this study will be to Thompson, and also analyze the influence of the type of buffer. The latest study, in Chapter 6, there will be about exhaust chaotic, but will deal with Pendulum cushioned and excited paramétricamente by a wave as Chapter 5 (starting with a sinusoidal signal-a joroba- be reached double hump , varying the parameter elliptical). It will be seen that the extent of the role of chaotic threshold, varying the parameter, introduced a minimum precisely when there is a change of simple double hump. Ends this work an appendix devoted to the Jacobi elliptic functions. It includes a brief history, and how these features arise from a natural evolution of the simplest cases: trigonométrico and hyperbolic. It will also be how can appear as a simple solution of differential equations. We describe some of the fields where, recently, it is using such functions successfully. Finally, indicating some expressions necessary for obtaining the Melnikov function in some of the earlier chapters (including certain developments in trigonometric series).

Author: Conesa del Valle Zaida.
Year: 2006.
University: AUTÓNOMA DE BARCELONA.
Place of defense: Ecole des Mines de Nantes.
Place of preparation: Departamento de Fisica (UAB) & Subatech (EMN, UN, IN2P3/CNRS).

Summary: Lattice QCD predicts a transition from an hadronic phase to a Quark Gluon Plasma phase, QGP, for temperatures above 10¨{13} K. Heavy-ion collisions are proposed to recreate it in the laboratory. With such purpose, the LHC will provide Pb-Pb collisions at 5.5 TeV/u, and the ALICE experiment will permit to explore them. In particular, the ALICE muon spectrometer will permit to investigate the muon related probes (quarkonia, open beauty,...). The expected apparatus performances to measure muons and dimuons are discussed. A factorization technique is employed to unravel the different contributions to the global efficiency. Results indicate that the detector should be able to measure muons up to pt = 100 GeV/c with a resolution of about 10%. We show that weak bosons production could be measured for the first time in heavy-ion collisions. Single muon pt and dimuons invariant mass distributions will probe W and Z production. As mainly muons from b- and c-quarks decays will populate the intermediate-pt of 5-25 GeV/c, heavy quark in-medium energy loss calculations indicate that the single muon spectra would be suppressed by a factor 2-4 in the most central 0-10% Pb-Pb collisions at 5.5 TeV. However, for pt > 35 GeV/c the weak boson decays are predominant, and no suppression is expected. Estimations indicate that the b- and W-muons crossing point shifts down in transverse momenta by 5 to 7 GeV/c in the most central 0-10% Pb-Pb collisions at 5.5 TeV.

Author: Monras Blasi Alexandre.
Year: 2006.
University: AUTÓNOMA DE BARCELONA.
Place of defense: Facultad de Ciencias, Dept. de Física.
Place of preparation: Facultad de Ciencias.

Summary: We discuss the quantum statistical techniques necessary to perform estimatcion of quantum states and quantum operations and processes. There is an emphasis on the analogy between the quantum formalism and the theory of the measure, and descuten papers published by the author.

Author: MASS VARELA JULIO ALBERTO.
Year: 2006.
University: VALLADOLID.
Place of defense: FACULTAD DE FÍSICA.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: Zinc oxide is a semiconducting material with a large potential for optoelectronic devices mainly pair manufacturing diode laser wavelength shorter. This material besides possess advantageous properties, it also has a few critical points that still need a better understanding to resolve issues related to its implementation. These hot spots are obtaining final ZnO tipo-p, a unified standard of the mechanisms that give rise to the visible luminescence and control of the area. This paper is a study of characterization through Catodoluminiscenica, in order to make some contributions in this regard, particularly in hydrothermal of ZnO crystals, which grow with several growth sectors and sides with different endings Oy Zn. The analysis microscopy and spectroscopy are based panchromatic images, SEM images, images spectral monkey CL. The study was conducted for different growth sectors and different sides of polarity Oy Zn. We analyze three spectral ranges that are excitónico, of the replicas fonónicas and visible. A different distribution of impurities and defects were noted for each region faces growth and polarity, as reflected in the behavior of gangs exitónica and visible spectra. The evolution of the CL intensity of the band excitónica depending on the kV is dependent recombination centers not raditivo, but also of deep centers and autoabsorción. The evolution of the CL intensity of the band exitónica depending on the current of electronic beam saturated at a higher intensity of the electron beam current in the region of growth prismatic (m) which means that there is increased presence of impurities in this growth sector and with less saturated intensity of the electron beam current for more kV, given that diminishes the presence of impurities in that sector growth and saturated with less intensity of the electron beam current for more kV, given that it diminishes impurities associated with this transition. The visible band is a broadband composed of at least three sub-bands green, yellow and red. These sub-bands are dominant according to the different growth areas, the green being the dominant region of growth prismatic yellow and orange in the region pyramidal growth. The evolution of eta band with kV distribution in depth evidence corroborating an increase in the presence of defects with deep levels that compete with the luminescence exitótinica weakening the latter in volume. The CL intensity of this band with the flow of electron beam saturated with greater intensity of the beam current at greater depth according to the study with kV. The bands observed in the spectral range of Mirrors fonónicas joined first and second wing replica fonónica optical longitudinal excitón free. The study of defects are associated primarily with a band emission band overlaps with the first replica fonónica, which is reinforced at the points of the shows where there are higher concentrations of defects in turn, is linked to the defects giving rise to the visible band. This new band associated with defects is replicated close of the second mirror fonónica optical longitudinal expressed by a widening of the band. The variation in the ratio between bands containing the first and second replica fonónica is associated with the degree of disorder introduced on the surface due to a technical polished químico-mecánico. Of those reasons that differs in the area of growth of basal plane is mostly affected by the polishing of the surface, while the prismatic growth area is the least affected. There are also different responses among the faces termination oxygen and zinc, given the differences in the mechanical properties and químic 8 as yal 1b1 to reactivity of the surface.