Measuring the transition to homogeneity with photometric redshift surveys

We study the possibility of detecting the transition to homogeneity using photometric redshift catalogs. Our method is based on measuring the fractality of the projected galaxy distribution, using angular distances, and relies only on observable quantites. It thus provides a way to test the Cosmological Principle in a model-independent unbiased way. We have tested our method on different synthetic inhomogeneous catalogs, and shown that it is capable of discriminating some fractal models with relatively large fractal dimensions, in spite of the loss of information due to the radial projection. We have also studied the influence of the redshift bin width, photometric redshift errors, bias, non-linear clustering, and surveyed area, on the angular homogeneity index H2 ({\theta}) in a {\Lambda}CDM cosmology. The level to which an upcoming galaxy survey will be able to constrain the transition to homogeneity will depend mainly on the total surveyed area and the compactness of the surveyed region. In particular, a Dark Energy Survey (DES)-like survey should be able to easily discriminate certain fractal models with fractal dimensions as large as D2 = 2.95. We believe that this method will have relevant applications for upcoming large photometric redshift surveys, such as DES or the Large Synoptic Survey Telescope (LSST).Comment: 14 pages, 14 figure

Estimation of single-cell parameters from a distribution of bacterial size

1 póster presentado al Cell Size Regulation EMBO Workshop, 14-18 September 2016Funding project DPI2014-54085-JINPeer reviewe

Integral Field Spectroscopy based H\alpha\ sizes of local Luminous and Ultraluminous Infrared Galaxies. A Direct Comparison with high-z Massive Star Forming Galaxies

Aims. We study the analogy between local U/LIRGs and high-z massive SFGs by comparing basic H{\alpha} structural characteristics, such as size, and luminosity (and SFR) surface density, in an homogeneous way (i.e. same tracer and size definition, similar physical scales). Methods. We use Integral Field Spectroscopy based H{\alpha} emission maps for a representative sample of 54 local U/LIRGs (66 galaxies). From this initial sample we select 26 objects with H{\alpha} luminosities (L(H{\alpha})) similar to those of massive (i.e. M\ast \sim 10^10 M\odot or larger) SFGs at z \sim 2, and observed on similar physical scales. Results. The sizes of the H{\alpha} emitting region in the sample of local U/LIRGs span a large range, with r1/2(H{\alpha}) from 0.2 to 7 kpc. However, about 2/3 of local U/LIRGs with Lir > 10^11.4 L\odot have compact H{\alpha} emission (i.e. r1/2 < 2 kpc). The comparison sample of local U/LIRGs also shows a higher fraction (59%) of objects with compact H{\alpha} emission than the high-z sample (25%). This gives further support to the idea that for this luminosity range the size of the star forming region is a distinctive factor between local and distant galaxies of similar SF rates. However, when using H{\alpha} as a tracer for both local and high-z samples, the differences are smaller than the ones recently reported using a variety of other tracers. Despite of the higher fraction of galaxies with compact H{\alpha} emission, a sizable group (\sim 1/3) of local U/LIRGs are large (i.e. r1/2 > 2 kpc). These are systems showing pre-coalescence merger activity and they are indistinguishable from the massive high-z SFGs galaxies in terms of their H{\alpha} sizes, and luminosity and SFR surface densities.Comment: Accepted for publication in A&A. (!5 pages, 7 figures, 2 tables

Reinforcing the link between the double red clump and the X-shaped bulge of the Milky Way

The finding of a double red clump in the luminosity function of the Milky Way bulge has been interpreted as evidence for an X-shaped structure. Recently, an alternative explanation has been suggested, where the double red clump is an effect of multiple stellar populations in a classical spheroid. In this Letter we provide an observational assessment of this scenario and show that it is not consistent with the behaviour of the red clump across different lines of sight, particularly at high distances from the Galactic plane. Instead, we confirm that the shape of the red clump magnitude distribution closely follows the distance distribution expected for an X-shaped bulge at critical Galactic latitudes. We also emphasize some key observational properties of the bulge red clump that should not be neglected in the search for alternative scenarios

Variables cinéticas de la batida relacionadas con el rendimiento del salto horizontal a pies juntos

El presente trabajo analiza las variables fuerza-tiempo (f-t), velocidad-tiempo (V-t) y potenciatiempo (P-t) que más se relacionan con la distancia del salto horizontal (SH), y discute sobre la validez de este test como predictor de la fuerza explosiva de las extremidades inferiores. Participaron 144 estudiantes de educación física (96 hombres y 48 mujeres) que realizaron 3 saltos verticales (SV) sobre plataforma de contacto y 3 SH sobre plataforma de fuerzas. Se obtuvieron correlaciones significativas (p<0.05) entre SH y f-t, SH y P-t (relativas al peso corporal) y SH y V-t. Paralelamente, se obtuvieron diferencias significativas (p<0.05) en estas variables entre hombres y mujeres (6-36%). También se obtuvieron altas relaciones (p<0.001) entre SH y SV en hombres y mujeres (r= 0.68 y r= 0.69, respectivamente). En conclusión, el test de SH es válido para evaluar la fuerza explosiva de las extremidades inferiores. Algunos aspectos metodológicos deben tenerse en cuenta para analizar y tratar las variables cinéticas del SH. Futuros trabajos deben seleccionar las variables cinéticas más importantes para corregir la técnica del SH.The present work analyzes the force-time (f-t), speed-time (V-t) and power-time (P-t) variables related with the standing long jump distance (SLJ). Also, this work analyzes the validity of the SLJ in order to predict the lower extremities explosive force. 144 physical education students (96 men and 48 women) participated in this study. The students carried out 3 vertical jumps (VJ) on contact mat, and 3 SLJ on force plate. We have obtained significant correlations (p<0.05) between SLJ and f-t, SLJ and P-t (relative to body weight) and SLJ and V-t variables. Significant differences (p<0.05) between men and women were obtained in these variables (6-36 %). Also, relationships between SLJ and VJ (p< 0.001) were obtained in men and women (r= 0.68 and r= 0.69, respectively). In conclusion, the SLJ test is valid in order to evaluate the lower extremities explosive force. Some methodological aspects are important in order to analyze the SLJ kinetic variables. Future works should select the most important SLJ kinetic variables in order to correct the SLJ technique

Creación de un treebank de dependencias universales mediante recursos existentes para lenguas próximas: el caso del gallego

[Resumen] En este trabajo presentamos una nueva estrategia para crear treebanks de lenguas con pocos recursos para el análisis sintáctico. El método consiste en la adaptación y combinación de diferentes treebanks anotados con dependencias universales de variedades lingüísticas próximas, con el objetivo de entrenar un analizador sintáctico para la lengua elegida, en nuestro caso el gallego. Durante el proceso de selección y adaptación de los treebanks de origen, analizamos el impacto de propiedades de tres niveles diferentes: (i) la distancia entre las lenguas de origen y destino, (ii) la adaptación de características léxico-ortográficas, y (iii) las directrices de anotación entre los treebanks. Usando la estrategia propuesta, entrenamos un analizador sintáctico estadístico para etiquetar, con resultados prometedores y sin datos previos de gallego, un pequeño corpus de esta lengua. La corrección manual de este corpus, usado como gold-standard, nos permitió probar la eficacia del método propuesto.Ministerio de Economía y Competitividad; FFI2014-51978-C2-1-RMinisterio de Economía y Competitividad; FJCI-2014-22853Ministerio de Economía y Competitividad; FFI2014-51978-C2-2-

New Treebank or Repurposed? On the Feasibility of Cross-Lingual Parsing of Romance Languages with Universal Dependencies

This is the final peer-reviewed manuscript that was accepted for publication in Natural Language Engineering. Changes resulting from the publishing process, such as editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document.[Abstract] This paper addresses the feasibility of cross-lingual parsing with Universal Dependencies (UD) between Romance languages, analyzing its performance when compared to the use of manually annotated resources of the target languages. Several experiments take into account factors such as the lexical distance between the source and target varieties, the impact of delexicalization, the combination of different source treebanks or the adaptation of resources to the target language, among others. The results of these evaluations show that the direct application of a parser from one Romance language to another reaches similar labeled attachment score (LAS) values to those obtained with a manual annotation of about 3,000 tokens in the target language, and unlabeled attachment score (UAS) results equivalent to the use of around 7,000 tokens, depending on the case. These numbers can noticeably increase by performing a focused selection of the source treebanks. Furthermore, the removal of the words in the training corpus (delexicalization) is not useful in most cases of cross-lingual parsing of Romance languages. The lessons learned with the performed experiments were used to build a new UD treebank for Galician, with 1,000 sentences manually corrected after an automatic cross-lingual annotation. Several evaluations in this new resource show that a cross-lingual parser built with the best combination and adaptation of the source treebanks performs better (77 percent LAS and 82 percent UAS) than using more than 16,000 (for LAS results) and more than 20,000 (UAS) manually labeled tokens of Galician.Ministerio de Economía y Competitividad; FJCI-2014-22853Ministerio de Economía y Competitividad; FFI2014-51978-C2-1-RMinisterio de Economía y Competitividad; FFI2014-51978-C2-2-