Estudio de la fatiga en pacientes con enfermedad de Parkinson : estudio preliminar

[Resumen] Antecedentes: Una de las quejas más habituales de los enfermos de Parkinson (EP) es la fatiga. La misma tiene un impacto perjudicial muy significativo sobre la calidad de vida de los pacientes. Los mecanismos que subyacen a este síntoma aún no son bien conocidos. Para el estudio de la fatiga se hace necesario establecer unos marcadores neurofisiológicos y observar si su comportamiento difiere en EP y en personas sanas. La comprensión de estos mecanismos podría ayudar a optimizar los tratamientos del síntoma. Objetivos: Revisar las distintas técnicas funcionales objetivas para la evaluación de la fatiga, y su aplicación en EP; e iniciar un protocolo (preliminar) que permita la evaluación de la fatiga en EP, y por tanto establecer marcadores específicos objetivables. Método: Los 8 participantes incluían: 2 EP, 3 jovenes sanos y 3 mayores sanos. Para la evaluación de la fatiga se utilizaron técnicas neurofisiológicas durante la acción del músculo flexor radial del carpo; estas fueron la estimulación magnética transcraneal (EMT) de M1, a través del cual obtenemos la amplitud del potencial motor evocado (PME) y el período de silencio (PS); y la estimulación eléctrica sobre el nervio que permite obtener la onda H y la onda M máxima. La tarea realizada consistía en realizar una contracción voluntaria submáxima (CVSM) isométrica de forma prolongada, hasta el fallo muscular. Resultados: El análisis preliminar (caso a caso) de las variables reflejan que: la duración de la prueba de CVSM presenta una gran variabilidad entre los sujetos. En el PME se observa un crecimiento sustancial de su tamaño durante la CVSM. Tanto el PME como el PS tienen, en general, una tendencia a incrementarse con la fatiga en todos los grupos. Discusión: El protocolo es viable a pesar de algunas dificultades, como la constatación, ya observada en otros estudios, de que la intensidad de estimulación eléctrica para conseguir la onda M máxima es mal tolerada o no tolerada por algunos sujetos, por lo cual habría que buscar alguna alternativa para el registro de las variables obtenidas con esta técnica.Traballo fin de mestrado (UDC.CIE). Curso 2014/201

Star formation in the warped outer pseudoring of the spiral galaxy NGC 3642

NGC 3642 was classified as a spiral galaxy with three rings and no bar. We have performed an HI and optical study of this nearly face-on galaxy. We find that the nuclear ring might in fact be part of an inner one-armed spiral, that could be driving nuclear accretion and feeding the central activity in the inner kpc. The inner ring is faint, and the outer ring is a rather ill-defined pseudoring. Furthermore, the size ratio of the rings is such that they cannot be due to a single pattern speed linking them together. The outer pseudoring is peculiar, since it lies in the faint outer parts of the disk, where star formation is still going on at 1.4 times the optical radius. Higher HI column densities are associated with these regions and the atomic gas layer is warped. These perturbations affect only the outer disk, since the kinematics within the main body conforms well to an ordinary differentially rotating disk. We propose here that both nuclear activity and star formation in the warped outer parts might be linked to the fact that NGC 3642 is located in a rich environment, where its close neighbors show clear signs of merging. Our suggestion is that NGC 3642 has captured recently a low-mass, gas-rich dwarf, and star formation was triggered in this infalling external gas that produced also a pronounced warp in the gaseous disk.Comment: Accepted for publication in A&A. Full resolution version available at http://www.iaa.es/~lourdes/3642/H3551.tar.g

Neural network ensembles: Evaluation of aggregation algorithms

Ensembles of artificial neural networks show improved generalization capabilities that outperform those of single networks. However, for aggregation to be effective, the individual networks must be as accurate and diverse as possible. An important problem is, then, how to tune the aggregate members in order to have an optimal compromise between these two conflicting conditions. We present here an extensive evaluation of several algorithms for ensemble construction, including new proposals and comparing them with standard methods in the literature. We also discuss a potential problem with sequential aggregation algorithms: the non-frequent but damaging selection through their heuristics of particularly bad ensemble members. We introduce modified algorithms that cope with this problem by allowing individual weighting of aggregate members. Our algorithms and their weighted modifications are favorably tested against other methods in the literature, producing a sensible improvement in performance on most of the standard statistical databases used as benchmarks.Comment: 35 pages, 2 figures, In press AI Journa

Recovering isolated galaxies from large scale surveys: problems and strategies

The large survey programs being performed nowadays, being the SDSS their flagship, provide us with morphological parameters which allow for extraction of large galaxy samples. We will analyze the methodology for obtaining an AMIGA-like catalogue of isolated galaxies from the SDSS DR5 photometric catalogue of galaxy objects, together with the roadblocks found in the process, and suggested workarounds.Comment: 4 pages, 2 figures, to appear in the Proceedings of the International Conference CIG09: Galaxies in Isolation, held in May 19th in Granada, Spai

Divorcio con hijos por motivo de lesiones

Traballo fin de grao (UDC.DER). Dereito. Curso 2016/201

Revised positions for the CIG galaxies

We present revised positions for the 1051 galaxies belonging to the Karachentseva Catalog of Isolated Galaxies (CIG). New positions were calculated by applying SExtractor to the Digitized Sky Survey CIG fields with a spatial resolution of 1.2''. We visually checked the results and for 118 galaxies had to recompute the assigned positions due to complex morphologies (e.g. distorted isophotes, undefined nuclei, knotty galaxies) or the presence of bright stars. We found differences between older and newer positions of up to 38'' with a mean value of 2.96'' relative to SIMBAD and up to 38'' and 2.42'' respectively relative to UZC. Based on star positions from the APM catalog we determined that the DSS astrometry of five CIG fields has a mean offset in (RA, Dec) of (-0.90'',0.93'') with a dispersion of 0.4''. These results have been confirmed using the 2MASS All-Sky Catalog of Point Sources. The intrinsic errors of our method combined with the astrometric ones are of the order of 0.5''.Comment: 6 pages, 7 figures. Accepted for publication in A&A. The data can be downloaded at http://www.iaa.csic.es/AMIGA.htm

El cultiu i el comerç de safrà a Catalunya durant l'edat mitjana

Inicialment, el safrà apareix com un producte de l’Orient mediterrani i tot sembla indicar que no fou fins al segle X que el cultiu va introduir-se a al-Àndalus; d’aquí l’etimologia àrab del nom. En el cas català, l’expansió va produir-se sobretot a partir del segle XIII, coincidint amb l’increment del consum de l’espècia a Europa, i ben aviat el rendiment elevat i la demanda creixent van fer que assolís un lloc molt destacat dins del panorama agrícola català. Els mercaders locals van trobar en el safrà un producte ideal per equilibrar la relació entre importacions i exportacions, i pels comerciants estrangers l’espècia va resultar molt útil a l’hora de reinvertir els beneficis que obtenien amb la venda dels productes manufacturats que portaven al Principat. Com es pot suposar, la conseqüència lògica d’aquesta expansió agrícola i comercial fou l’establiment, des del començament del segle XIII, d’impostos i exaccions sobre el safrà en tots els àmbits.Peer Reviewe