Towards a new spacetime paradigm : Gauge symmetries and post-Riemann geometries in gravitation

In this thesis the geometrical methods and symmetry principles in gravitation are explored motivating a new perspective into the spacetime paradigm. The effects of post-Riemann spacetime geometries with torsion are studied in applications to fundamental fermionic and bosonic fields, cosmology, astrophysics and gravitational waves. The physical implications and related phenomenological considerations of this study are addressed, and the fundamental ideas related to spacetime physics, motivated by geometrical methods and symmetry principles, are also discussed in the context of the possible routes towards a new spacetime paradigm in gravitation and unified field theories. We explore the analogies between the gauge approach to gravity and the pre-metric approach to electrodynamics, within the exterior calculus of forms. These analogies are developed, reinforcing the hypothesis of the primacy of the conformal structure over the metric structure. Since the conformal symmetries seem to be broken symmetries in nature, the Poincar´e gauge theories of gravity (PGTG) are taken into consideration. These presuppose a Riemann-Cartan (RC) spacetime geometry with curvature and torsion and motivate the search for torsion effects in physical systems. We study both minimal and non-minimal couplings of fermionic spinors to the background torsion and find changes in the energy levels (in the flat spacetime limit), including parity breaking effects. The Einstein-Cartan-Dirac-Maxwell theory is explored including its cosmological applications. The presence of minimal couplings to torsion induces non-linearities and non-minimal couplings in the matter fields dynamics and the resulting cosmological model is non-singular, including early and future bounces, early acceleration and torsion induced dark-energy due to fermionic vacuum condensates. Some potential astrophysical applications due to the torsion interaction with fermionic and bosonic fields are also considered as well as the effects of curvature in electromagnetic fields, including the extensions with inhomogeneous and anisotropic constitutive electromagnetic relations that respect the local isometries. In this context, the Parametrized Post-Newtonian (PPN) formalism is also implemented, making a bridge with the testing of different gravity theories. The effects of torsion are also analysed in gravitational wave (GW) physics, following the perturbations of a RC spacetime and in the field equations of a specific quadratic PGTG. The gravitational wave effects into electromagnetic fields are also studied with potential applications for non-standard detectors, which in principle could be extended for theories beyond GR, searches of extra polarizations and extra degrees of freedom

Análisis del rendimiento, percepción de esfuerzo y recuperación y toma de decisión en el arbitraje del fútbol profesional : un estudio del caso

Programa Oficial de Doutoramento en Saúde e Motricidade Humana. 5002V01[Resumo] A presente investigación analiza o rendemento, a percepción de esforzo e recuperación e a toma de decisión en partidos oficiais dun árbitro profesional da primeira división do fútbol español. Analizáronse todos os partidos da temporada 2012-2013 nos que o suxeto de estudio foi designado coma árbitro principal (N= 19). Os instrumentos utilizados para a análise do rendemento foron un pulsómetro-GPS que portaba o árbitro e empregaba coma cronógrafo oficial en cada encontro, e a grabación en video dos partidos para a obtención de parámetros cinemáticos (duración, distancia percorrida, velocidade media e máxima, tempo en movimento, velocidade media en movimento) fisiolóxicos (frecuencia cardiaca media e máxima, gasto enerxético) e de toma de decisión de accións determinantes para o xogo (tarxetas amarelas, tarxetas bermellas, penaltis, concesión de gol). Para a análise da percepción de esforzo empregáronse as escalas RPE (Rating Perceived Exertion) de Borg e a escala CR10 de Borg modificada (Category scales with Ratio properties) mentres que, para a percepción da recuperación, empregáronse a escala TQR (Total Quality Recovery). Tras os resultados obtidos, pódese afirmar que a toma de decisión realízase baixo condicións de alta frecuencia cardiaca en relación coa velocidad de desprazamento. Neste senso, no momento da sinalización, a frecuencia cardiaca e a velocidade de desprazamento son máis elevadas que os valores promedio da totalidade de cada encontro.[Resumen] La presente investigación analiza el rendimiento, la percepción de esfuerzo y recuperación y la toma de decisión en partidos oficiales de un árbitro profesional de la primera división del fútbol español. Se analizaron todos los partidos de la temporada 2012-2013 en los que el sujeto de estudio fue designado como árbitro principal (N= 19). Los instrumentos utilizados para el análisis del rendimiento fueron un pulsómetro-GPS que portaba el árbitro y empleaba como cronógrafo oficial en cada encuentro, y la grabación en video de los partidos para la obtención de parámetros cinemáticos (duración, distancia recorrida, velocidad media y máxima, tiempo en movimiento, velocidad media en movimiento) fisiológicos (frecuencia cardiaca media y máxima, gasto energético) y de toma de decisión de acciones determinantes para el juego (tarjetas amarillas, tarjetas rojas, penaltis, concesión de gol). Para el análisis de la percepción de esfuerzo se han empleado las escalas RPE (Rating Perceived Exertion) de Borg y la escala CR10 de Borg modificada (Category scales with Ratio properties) mientras que, para la percepción de la recuperación, se ha empleado la escala TQR (Total Quality Recovery). Tras los resultados obtenidos, se puede afirmar que la toma de decisión se realiza bajo condiciones de alta frecuencia cardiaca en relación con su velocidad de desplazamiento.[Abstract] The present research analyzes the performance, the perception of effort and recovery, and the decisión making of a professional referee of the first Spanish division in official football matches. A total number of nineteen matches of the 2012/2013 season, in which the protagonist of the investigation was designed as the main referee, were analyzed. The analysis tools used to test the referee’s performance were a GPS heart rate monitor he utilised as an official chronograph in each football match and the video recording of the matches to obtain cinematic parameters (duration, distance run, average and highest speed, time in motion, average speed in motion), physiological ones (medium and maximum heart rate, energy expenditure) and decision making of decisive actions for the game (yellow cards, red cards, penalty shots and goal conceding). Borg’s RPE (Rating Perceived Exertion) and CR10 modified scales (Category scales with Ratio properties) have been used to analyse effort perception. TQR (Total Quality Recovery) scale has been used to measure recovery perception. After having obtained the analysis results, it can be stated that decision making is done under high heart rate frequency in relation to displacement speed. In this sense, at the time of signalling something, heart rate and displacement speed are higher than the average values of the whole of each encounter

Implantación de metodologías de planificación estratégica en la universidad, identificación de indicadores y medición de activos intangibles

Después del largo camino recorrido esta última década en la implantación de los programas de calidad en el sistema universitario español, se mantiene cierta incertidumbre sobre el grado de influencia de dichos programas en la toma de decisiones. En ese contexto se ha diseñado un estudio prospectivo, mediante la aplicación de la técnica de investigación social Delphi, con objeto de evaluar el grado de implantación de la metodología del Cuadro de Mando Integral (Balanced Scorecard) en las universidades de la Comunidad de Madrid, así como averiguar la opinión del grupo de expertos sobre la posibilidad de condensación de los indicadores y sobre la medición de activos intangibles. En la comunicación propuesta se incluirá un análisis de las conclusiones obtenidas

Geometrical methods in electromagnetism and gravitation: gravitoelectromagnetism and gravity with torsion (with cosmological applications)

Tese de mestrado em Física, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012Principais motivações que orientam a linha de investigação na qual a tese se insere: - Aprofundar o estudo da relação íntima entre geometria e física; - Estudar as analogias e o acoplamento entre gravidade e electromagnetismo usando métodos geométricos, compreendendo a possibilidade de importantes aplicações teóricas e tecnológicas, podendo mesmo ser relevante para a astrofísica, a cosmologia e, eventualmente, no caminho para uma teoria consistente da gravidade quântica; - Estudar o gravitoelectromagnetismo e suas aplicações astrofísicas e eventualmente tecnológicas; - Explorar a noção de torsão em geometria diferencial e sua importância em física, nomeadamente no âmbito das teorias de gravitação. Enquadramento geral e tópicos principais da dissertação. Relação entre geometria e Natureza - relação entre geometria e física. • Importância dos métodos geométricos no estudo do campo eletromagnético e da gravidade e na exploração das analogias e acoplamento entre estas duas interações: • Axiomática do electromagnetismo; • Gravitoelectromagnetismo; • Acoplamento entre gravidade e electromagnetismo; • Gravidade com torsão: - Relevância teórica. Diferentes modelos; - Alguns modelos cosmológicos; - Exploração das analogias entre gravidade e electromagnetismo; - Testes experimentais. A questão da interpretação do papel das estruturas geométricas do espaço-tempo em física é abordada, realçando algumas reflexões relacionadas com a geometrização da física, motivadas pelo estudo das analogias e acoplamento entre gravidade e electromagnetismo. Neste âmbito a noção da ontologia física do espaço-tempo é brevemente abordada na sua conexão com as teorias unificadas.Although this work contains many personal investigations, interpretations and ideas, it was mainly constructed as a review compilation on several selected topics concerning the electromagnetic and gravitational studies using geometrical methods. The selected topics and their sources reflect the author’s interests and were compiled together and organized into a single framework in order to construct a meaningful and solid line of research on the related topics of gravitation and electromagnetism. One could say that this project fits within the wider scientific arena for research on the relation between geometry and physics and the nature of space and time. Some of the topics addressed, such as the coupling of gravity and electromagnetism, gravitoelectromagnetism and gravity with torsion, are areas of active research from the theoretical side but it’s the author’s conviction that these studies will eventually reveal many astonishing practical (technological) applications. Main motivations and research lines: - To deepen the study on the profound relation between geometry and physics and the nature of space and time; - To study the analogies and physical coupling between gravity and electromagnetism using geometrical methods, considering the possibility of important theoretical (and technological) applications, being relevant for astrophysics, cosmology and, eventually, for the search of a consistent theory of quantum gravity; - To study gravitoelectromagnetism from a theoretical point of view as well as its astrophysical and technological applications; - To explore the notion of torsion in differential geometry and its importance in physics, namely in classical and quantum gravitation, unified theories of interactions and cosmology; - To explore, using the already mentioned analogies, to which extent is it possible to have a geometrical explanation of “inertial forces” (compatible with the equivalence principle), seen as geometrical deformations of space-time, such as curvature and torsion. (Not all of these topics are covered in the present work but these are the main research lines that motivate this and future projects) General conceptual framework and main topics present in this thesis Relation between geometry and physics: Importance of geometrical methods in the study of the electromagnetic and gravitational fields and in the exploration of the analogies and coupling between these physical interactions: - Axiomatic of the electromagnetism; - Coupling between gravity and electromagnetism; - Gravitoelectromagnetism and GP-B experiment; - Gravity with torsion: • Theoretical relevance of extended theories of gravity. Different models with torsion and interpretations; • Some cosmological applications; • Exploration of the analogies and coupling between gravity and electromagnetism. • Testing space-time torsion - The work suggests the idea that the electromagnetic properties of “empty space” might be interpreted as geometrical properties of the space-time continuum and that electromagnetic and gravitational waves should be fundamentally connected and be mutually generated. In this sense, it also reinforces the need to rethink the concept of “vacuum” in physics. It is also briefly explored the possibility of a geometrical description of the electromagnetic field.. - Being essentially devoted to geometrical methods in the study of the electromagnetic and gravitational fields and to the role of space-time (geometrical) structures in these field theories, this work enhances the philosophical debate on the nature of space and time inspired by ideas coming from physics. On the last part it discusses some relevant open questions such as the possibility of a coherent physicalism of space-time and the geometrization of fundamental structures such as Higgs fields

Formation of galaxies in {\Lambda}CDM cosmologies. I. The fine structure of disc galaxies

We present a detailed analysis of the global and fine structure of four middle-mass disc galaxies obtained from simulations in a $\Lambda$CDM scenario. These objects have photometric D/T ratios in good agreement with those observed for late-type spirals, as well as kinematic properties in agreement with the observational Tully-Fisher relation. We identify the different dynamical components at z=0 on the basis of both orbital parameters and the binding energy of stars in the galaxy. In this way, we recognize a slowly rotating centrally concentrated spheroid, and two disc components supported by rotation: a thin disc with stars in nearly circular orbits, and a thick disc with orbital parameters transitional between the thin disc and the spheroid. The spheroidal component is composed mainly by old, metal-poor and {\alpha}-enhanced stars. The distribution of metals in this component shows, however, a clear bimodality with a low-metallicity peak, which could be related to a classical bulge, and a high-metallicity peak, which could be related to a pseudo-bulge. The thin disc appears in our simulations as the youngest and most metal-rich component. The radial distribution of ages and colours in this component are U-shaped: the new stars are forming in the inner regions, and then migrate through secular processes. Finally, we also find a thick disc containing about 16% of the total stellar mass and with properties that are intermediate between those of the thin disc and the spheroid. Its low-metallicity stars are {\alpha}-enhanced when compared to thin disc stars of the same metallicity. The structural parameters (e.g., the scale height) of the simulated thick discs suggest that such a component could result from the combination of different thickening mechanisms that include merger-driven processes, but also long-lived internal perturbations of the thin disc. [Abridged]Comment: 23 pages, 16 figures, accepted for publication in MNRAS, references fixe

Cross-Platform Social Web Application for Older Adults with HTML 5

Online social networks can potentially play an important role in connecting older adults with family and friends who often live far. However, adoption of social Web services among the elderly is still very limited because the user interfaces are not adapted to them and also because few of their friends use such services. This paper introduces a mobile Web application designed with older adults' characteristics in mind that integrates a popular social network

A decision support tool (R-SWAT-DS) for integrated watershed management

Best management practices (BMPs) can be used effectively to reduce nutrient and sediment loads generated from point sources or non-point sources to receiving water bodies. Methodologies for optimal, cost effective BMP selection and placement are needed to assist watershed management planners and stakeholders. We developed a modeling-optimization framework that can be used to find cost-effective solutions of BMP placement to attain nutrient load reduction targets. The framework integrates the Soil and Water Assessment Tool (SWAT) watershed model, spatial representation of BMPs, an economic component, and multi-objective optimization routines in the R environment. The framework can be used to launch individual or iterative BMPs simulations, or search for optimal strategies. Advanced plotting, mapping and statistical analysis functionalities that facilitate the interpretation and assessment of the results are included

Chemical characteristics of groundwaters at two massive sulphide deposits in an area of previous mining contamination, South Iberian Pyrite Belt, Spain

A detailed chemical study of groundwater was carried out to elucidate the processes controlling the oxidation and dissolution of sulphide minerals at two massive sulphide deposits in the Iberian Pyrite Belt (IPB), i.e. the mined La Zarza deposit and the unmined Masa Valverde deposit. It was found that major-element compositions varied according to the hydrological regime, La Zarza being in a relatively high area with groundwater recharge (and disturbance due to the human factor) and Masa Valverde being in a relatively low area with groundwater discharge. The variations mainly concem pH, Eh, S04 and Na concentrations. Metal concentrations were determined (a) by ICP-MS after filtration, and (b) in sorne cases by voltammetric measurement of Cu, Pb, Zn, Cd and Mn using the Voltammetric In situ Profiling (VIP) System, which allows detection of only the mobile fractions of trace elements (i.e., free metal ions and small labile complexes a few nanometers in size). If one compares the results obtained by each of the two methods, it would appear that the groundwater shows significant enhancement of metal solubility through complexing with organic matter andlor adsorption onto colloids andlor small particles. In areas of sulphide oxidation, however, this solubility enhancement decreases according to Cu> Zn>Cd>Pb. Dnder very low redox conditions, the attained metal concentrations can be several orders of magnitude (up to 108-1 09 for Cu and 102-103 for Pb) larger than those expected from equilibrium with respect to sulphide minerals as calculated with the EQ3NR geochemical code; Zn concentrations, however, are close to equilibrium with respect to sphalerite. The implication of these results is discussed with respect both to mineral exploration and to environmental issues

Comparison between the AFNOR Method and the Imposition of Balanced Maximum Specific Sliding in the Imposed Centre Distance Problem

Successive editions of Henriot’s treatise on gears, and an AFNOR document, present an approximate procedure for the choice of profile shift values for the pinion and wheel when a center distance value is imposed in a cylindrical gear pair. That procedure aims at achieving an approximate balancing of the maximum specific sliding values of the pinion and of the wheel. The method involves a loosely defined choice of an auxiliary parameter, but no information is available relating this choice with the level of attainment of the intended balancing of maximum specific sliding values. This assessment, if needed, requires a subsequent analysis for verification. Since no information is available evaluating the procedure, the purpose of this work is to provide a thorough rigorous analysis of the method, highlighting its qualities but also its shortcomings