Noise characterization of an atomic magnetometer at sub-millihertz frequencies

Noise measurements have been carried out in the LISA bandwidth (0.1 mHz to 100 mHz) to characterize an all-optical atomic magnetometer based on nonlinear magneto-optical rotation. This was done in order to assess if the technology can be used for space missions with demanding low-frequency requirements like the LISA concept. Magnetometry for low-frequency applications is usually limited by $1/f$ noise and thermal drifts, which become the dominant contributions at sub-millihertz frequencies. Magnetic field measurements with atomic magnetometers are not immune to low-frequency fluctuations and significant excess noise may arise due to external elements, such as temperature fluctuations or intrinsic noise in the electronics. In addition, low-frequency drifts in the applied magnetic field have been identified in order to distinguish their noise contribution from that of the sensor. We have found the technology suitable for LISA in terms of sensitivity, although further work must be done to characterize the low-frequency noise in a miniaturized setup suitable for space missions.Comment: 11 pages, 12 figure

Statistical anatomical modelling for efficient and personalised spine biomechanical models

Personalised medicine is redefining the present and future of healthcare by increasing treatment efficacy and predicting diseases before they actually manifest. This innovative approach takes into consideration patient’s unique genes, environment, and lifestyle. An essential component is physics-based simulations, which allows the outcome of a treatment or a disease to be replicated and visualised using a computer. The main requirement to perform this type of simulation is to build patient-specific models. These models require the extraction of realistic object geometries from images, as well as the detection of diseases or deformities to improve the estimation of the material properties of the studied object. The aim of this thesis was the design of a general framework for creating patient- specific models for biomechanical simulations using a framework based on statistical shape models. The proposed methodology was tested on the construction of spine models, including vertebrae and intervertebral discs (IVD). The proposed framework is divided into three well-defined components: The paramount and first step is the extraction of the organ or anatomical structure from medical images. In the case of the spine, IVDs and vertebrae were extracted from Magnetic Resonance images (MRI) and Computed Tomography (CT), respectively. The second step is the classification of objects according to different factors, for instance, bones by its type and grade of fracture or IVDs by its degree of degeneration. This process is essential to properly model material properties, which depends on the possible pathologies of the tissue. The last component of the framework is the creation of the patient-specific model itself by combining the information from previous steps. The behaviour of the developed algorithms was tested using different datasets of spine images from both computed tomography (CT) and Magnetic resonance (MR) images from different institutions, type of population and image resolution

Las traducciones de García Gutiérrez: Estelle ou le père et la fille. Análisis de una traducción

Visión general del panorama histórico y literario del siglo XIX en España, incluyendo el papel de la traducción de obras teatrales. Revisión de la figura de Antonio García Gutiérrez y análisis y comparación de su traducción de la obra Estelle ou le père et la fille. Reflexión sobre los cambios efectuados en ella, poniendo de manifiesto de la diversa modelización entre los usos decimonónicos y los actuales.Grado en Traducción e Interpretació

El culto a la muerte en Internet: Nuevos horizontes espacio-temporales

Aquest treball és una reflexió sobre les noves pràctiques socials que entorn de la mort s'estan produint a Internet, i especialment a les xarxes socials de la Web 2.0. Gràcies a la revolució tecnològica, pràctiques, valors, creences i rituals funeraris són deslocalitzats dels seus contextos habituals de producció i readaptats en nous entorns ubics on es reinventa el culte als morts i a la seva memòria.This work is a reflection on new social practices around death that are taking place on Internet, especially in social networks of Web 2.0. Thanks to the technological revolution, practices, values, beliefs and funeral rituals are de-territorialized, dislocated from their usual contexts of production, and are re-adapted in new ubiquitous environments where the cults of the dead and to his memory are reinvented.Este trabajo es una reflexión sobre las nuevas prácticas sociales que en torno a la muerte se están produciendo en Internet, y en especial en las redes sociales de la Web 2.0. Gracias a la revolución tecnológica, prácticas, valores, creencias y rituales funerarios son desterritorializados, desubicados de sus contextos habituales de producción, y re-adaptados en nuevos entornos ubicuos donde se reinventa el culto a los muertos y a su memoria.

La construcción de lo sagrado: Santa Eulalia de Mérida (y su extensión por el levante español)

Este trabajo representa un esfuerzo para comprender y desentrañar el corazón del fenómeno religioso, lo sagrado, su creación y algunas de sus múltiples formas de encarnación. La pretensión es estudiar el modo en que algunas comunidades sociales entienden la realidad trascendente de lo sagrado y sus manifestaciones: el mito, el símbolo, el ritual y la fiesta. Expresiones que constituyen, los modos principales de explicación y de aproximación, por parte de las comunidades, a ese universo simbólico. El fundamento de esta investigación antropológica es estudiar la producción de convenciones particulares actuales, contextuales, históricas y artísticas que construyen a Santa Eulalia en Mérida y la transforman en una creación mítica y en un símbolo que se expande re-inventándose, de acuerdo con la época y la ideología a la que sirve, por el Levante español, en Barcelona y en Totana (Murcia).This work represents an effort to understand and to uncover the heart of the religious phenomenon, the sacred thing, his creation and some of his multiple forms of incarnation. The pretension is to study the way in which some social communities understand the transcendent reality of the sacred thing and his manifestations: the myth, the symbol, the ritual and the holiday. Expressions that they constitute the principal manners of explanation and of approximation, on the part of the communities, to this symbolic universe. The foundation of this anthropologic investigation is to study the production of particular current, contextual, historical and artistic conventions that they construct Holy Eulalia in Merida and transform it into a mythical creation and in a symbol that expands re-inventándose, in agreementin agreement with the epoch and the ideology to the one that serves, for the Spanish Levant, in Barcelona and in Totana (Murcia)

Is the von Krmn constant affected by sediment suspension?

Is the von Krmn constant affected by sediment suspension? The presence of suspended sediment in channels and fluvial streams has been known for decades to affect turbulence transfer mechanism in sediment-laden flows, and, therefore, the transport and fate of sediments that determine the bathymetry of natural water courses. This study explores the density stratification effects on the turbulent velocity profile and its impact on the transport of sediment. There is as yet no consensus in the scientific community on the effect of sediment suspension on the von Krmn parameter, . Two different theories based on the empirical log-wake velocity profile are currently under debate: One supports a universal value of =0.41 and a strength of the wake, , that is affected by suspended sediment. The other suggests that both and could vary with suspended sediment. These different theories result in a conceptual problem regarding the effect of suspended sediment on , which has divided the research area. In this study, a new mixing length theory is proposed to describe theoretically the turbulent velocity profile. The analytical approach provides added insight defining as a turbulent parameter which varies with the distance to the bed in sediment-laden flows. The theory is compared with previous experimental data and simulations using a k-turbulence closure to the Reynolds averaged Navier Stokes equations model. The mixing length model indicates that the two contradictory theories incorporate the stratified flow effect into a different component of the log-wake law. The results of this work show that the log-wake fit with a reduced is the physically coherent approximation. © 2012. American Geophysical Union. All Rights Reserved.This research was partially funded by the project P08-AGR-03925 (Junta de Andalucía).Peer Reviewe

Towards a FPGA-controlled deep phase modulation interferometer

Deep phase modulation interferometry was proposed as a method to enhance homodyne interferometers to work over many fringes. In this scheme, a sinusoidal phase modulation is applied in one arm while the demodulation takes place as a post-processing step. In this contribution we report on the development to implement this scheme in a fiber coupled interferometer controlled by means of a FPGA, which includes a LEON3 soft-core processor. The latter acts as a CPU and executes a custom made application to communicate with a host PC. In contrast to usual FPGA-based designs, this implementation allows a real-time fine tuning of the parameters involved in the setup, from the control to the post-processing parameters.Comment: Proceedings of the X LISA Symposium, Gainesville, May 18-23, 201

Interpolation of the magnetic field at the test masses in eLISA

A feasible design for a magnetic diagnostics subsystem for eLISA will be based on that of its precursor mission, LISA Pathfinder. Previous experience indicates that magnetic field estimation at the positions of the test masses has certain complications. This is due to two reasons. The first is that magnetometers usually back-act due to their measurement principles (i.e., they also create their own magnetic fields), while the second is that the sensors selected for LISA Pathfinder have a large size, which conflicts with space resolution and with the possibility of having a sufficient number of them to properly map the magnetic field around the test masses. However, high-sensitivity and small-sized sensors that significantly mitigate the two aforementioned limitations exist, and have been proposed to overcome these problems. Thus, these sensors will be likely selected for the magnetic diagnostics subsystem of eLISA. Here we perform a quantitative analysis of the new magnetic subsystem, as it is currently conceived, and assess the feasibility of selecting these sensors in the final configuration of the magnetic diagnostic subsystem.Peer ReviewedPostprint (author's final draft