Observational hints of radial migration in disc galaxies from CALIFA

Context. According to numerical simulations, stars are not always kept at their birth galactocentric distances but they have a tendency to migrate. The importance of this radial migration in shaping galactic light distributions is still unclear. However, if radial migration is indeed important, galaxies with different surface brightness (SB) profiles must display differences in their stellar population properties. Aims: We investigate the role of radial migration in the light distribution and radial stellar content by comparing the inner colour, age, and metallicity gradients for galaxies with different SB profiles. We define these inner parts, avoiding the bulge and bar regions and up to around three disc scale lengths (type I, pure exponential) or the break radius (type II, downbending; type III, upbending). Methods: We analysed 214 spiral galaxies from the CALIFA survey covering different SB profiles. We made use of GASP2D and SDSS data to characterise the light distribution and obtain colour profiles of these spiral galaxies. The stellar age and metallicity profiles were computed using a methodology based on full-spectrum fitting techniques (pPXF, GANDALF, and STECKMAP) to the Integral Field Spectroscopic CALIFA data. Results: The distributions of the colour, stellar age, and stellar metallicity gradients in the inner parts for galaxies displaying different SB profiles are unalike as suggested by Kolmogorov-Smirnov and Anderson-Darling tests. We find a trend in which type II galaxies show the steepest profiles of all, type III show the shallowest, and type I display an intermediate behaviour. Conclusions: These results are consistent with a scenario in which radial migration is more efficient for type III galaxies than for type I systems, where type II galaxies present the lowest radial migration efficiency. In such a scenario, radial migration mixes the stellar content, thereby flattening the radial stellar properties and shaping different SB profiles. However, in light of these results we cannot further quantify the importance of radial migration in shaping spiral galaxies, and other processes, such as recent star formation or satellite accretion, might play a role

Effects of carbohydrate–protein beverages on recovery of the exercise

Este artículo aporta una revisión del efecto de la coingesta de la proteína de suero de leche y proteína caseína administradas en bebidas carbohidratadas, sobre la recuperación y los parámetros del daño muscular en ejercicios de larga duración. La búsqueda se ha realizado en abril de 2013 en las bases de datos del ISI Web of Knowledge, SCOPUS, Sport Discuss, PubMed, Medline Sportdiscus, y en las bases de datos CINDOC en las redes CTI-CSIC, RESH, DICE y DIALNET cruzando los descriptores “Exercise”, “Resistance training” y “Recovery” con los términos “Ergogenic beverage”, “Casein Protein” y “Whey Protein”. La estrategia nutricional más respaldada es la ingesta de un preparado líquido carbohidratado en donde se combinan proteínas de diferentes fuentes sobre pruebas de esfuerzos prolongados similares a la competición tanto en deportes individuales como en colectivos, con resultados discrepantesThis manuscript shows a review about the effects of the whey and casein protein on recovery and parameters of muscle damage in long-term exercise. The search was conducted in April 2013 in the databases of ISI Web of Knowledge, SCOPUS, PubMed, Medline, SportDiscus, and databases on Spanish networks CINDOC CTI-CSIC, RESH, DICE, and DIALNET crossing the descriptors "Exercise", "Resistance training" and "Recovery" with the terms "Ergogenic Beverage", "Casein Protein" and "Whey Protein". The most used nutritional strategies are based in a carbohydrate beverage which combines different protein sources on prolonged exercise tests similar to sports competition, in both individual and collective sports, with discrepant result

Central star formation and metallicity in CALIFA interacting galaxies

We use optical integral-field spectroscopic (IFS) data from 103 nearby galaxies at different stages of the merging event, from close pairs to merger remnants provided by the CALIFA survey, to study the impact of the interaction in the specific star formation and oxygen abundance on different galactic scales. To disentangle the effect of the interaction and merger from internal processes, we compared our results with a control sample of 80 non-interacting galaxies. We confirm the moderate enhancement (2-3 times) of specific star formation for interacting galaxies in central regions as reported by previous studies; however, the specific star formation is comparable when observed in extended regions. We find that control and interacting star-forming galaxies have similar oxygen abundances in their central regions, when normalized to their stellar masses. Oxygen abundances of these interacting galaxies seem to decrease compared to the control objects at the large aperture sizes measured in effective radius. Although the enhancement in central star formation and lower metallicities for interacting galaxies have been attributed to tidally induced inflows, our results suggest that other processes such as stellar feedback can contribute to the metal enrichment in interacting galaxies.Comment: 9 pages, 9 figures. Accepted for publication in Astronomy & Astrophysic

Estudio biomecánico in vivo del grupo muscular flexor del codo en condiciones basales y su respuesta a la fatiga.

El objetivo del presente trabajo es establecer una aproximación al patrón de referencia habitual de la biomecánica del bíceps braquial y su respuesta a la fatiga. Sobre 37 voluntarios varones sanos se determinó una capacidad de contracción voluntaria máxima de flexión del codo de 266,8 ± 58,7N en el brazo dominante y de 258,2 ± 59,4N en el no dominante, que descendió a 211,5 ± 53N y 205,3 ± 56,5N respectivamente al someter a los voluntarios al test de fatiga (p<0,001 en ambos). El tiempo de fatiga se objetivó en 160,7 ± 72,8 s en el brazo dominante y en 156,7 ± 68,7 s en el no dominante. La supinación voluntaria máxima disminuyó de 208,7 ± 54N y 207 ± 54,8N hasta 194,1 ± 66,6N y 192,8 ± 66N respectivamente en el estudio postfatiga (p<0,001 en ambas). No se apreciaron diferencias significativas en el estudio de subgrupos por edades

Larger λR\lambda_R in the disc of isolated active spiral galaxies than in their non-active twins

We present a comparison of the spin parameter $\lambda_R$, measured in a region dominated by the galaxy disc, between 20 pairs of nearby (0.005$<$z$<$0.03) seemingly isolated twin galaxies differing in nuclear activity. We find that 80--82% of the active galaxies show higher values of $\lambda_R$ than their corresponding non-active twin(s), indicating larger rotational support in the AGN discs. This result is driven by the 11 pairs of unbarred galaxies, for which 100% of the AGN show larger $\lambda_R$ than their twins. These results can be explained by a more efficient angular momentum transfer from the inflowing gas to the disc baryonic matter in the case of the active galaxies. This gas inflow could have been induced by disc or bar instabilities, although we cannot rule out minor mergers if these are prevalent in our active galaxies. This result represents the first evidence of galaxy-scale differences between the dynamics of active and non-active isolated spiral galaxies of intermediate stellar masses (10$^{10}<M_*<10^{11}$ M$_{\odot}$) in the Local Universe.Comment: 11 pages, 7 figures. Accepted for publication in A&A Letter

Spiral-like star-forming patterns in CALIFA early-type galaxies

Based on a combined analysis of SDSS imaging and CALIFA integral field spectroscopy data, we report on the detection of faint (24 < {\mu}$_r$ mag/arcsec$^2$ < 26) star-forming spiral-arm-like features in the periphery of three nearby early-type galaxies (ETGs). These features are of considerable interest because they document the still ongoing inside-out growth of some local ETGs and may add valuable observational insight into the origin and evolution of spiral structure in triaxial stellar systems. A characteristic property of the nebular component in the studied ETGs, classified i+, is a two-radial-zone structure, with the inner zone that displays faint (EW(H\alpha)$\simeq$1{\AA}) low-ionization nuclear emission-line region (LINER) properties, and the outer one (3{\AA}<EW(H\alpha)<~20{\AA}) HII-region characteristics. This spatial segregation of nebular emission in two physically distinct concentric zones calls for an examination of aperture effects in studies of type i+ ETGs with single-fiber spectroscopic data.Comment: Accepted to A&A, 5 pages, 1 figur

Spectroscopic aperture biases in inside-out evolving early-type galaxies from CALIFA

Integral field spectroscopy studies based on CALIFA data have recently revealed the presence of ongoing low-level star formation (SF) in the periphery of ~10% of local early-type galaxies (ETGs), witnessing a still ongoing inside-out galaxy growth process. A distinctive property of the nebular component in these ETGs, classified i+, is a two-radial-zone structure, with the inner zone displaying LINER emission with a H\alpha equivalent width EW~1{\AA}, and the outer one (3{\AA}<EW<~20{\AA}) showing HII-region characteristics. Using CALIFA IFS data, we empirically demonstrate that the confinement of nebular emission to the galaxy periphery leads to a strong aperture (or, redshift) bias in spectroscopic single-fiber studies of type i+ ETGs: At low redshift (<~0.45), SDSS spectroscopy is restricted to the inner (SF-devoid LINER) zone, thereby leading to their erroneous classification as "retired" galaxies (systems lacking SF and whose faint emission is powered by pAGB stars). Only at higher z's the SDSS aperture can encompass the outer SF zone, permitting their unbiased classification as "composite SF/LINER". We also demonstrate that the principal effect of a decreasing aperture on the classification of i+ ETGs via standard BPT emission-line ratios consists in a monotonic up-right shift precisely along the upper-right wing of the "seagull" distribution. Motivated by these insights, we also investigate theoretically these biases in aperture-limited studies of inside-out growing galaxies as a function of z. To this end, we devise a simple model, which involves an outwardly propagating SF process, that reproduces the radial extent and two-zone EW distribution of i+ ETGs. By simulating on this model the spectroscopic SDSS aperture, we find that SDSS studies at z<~1 are progressively restricted to the inner LINER-zone, and miss an increasingly large portion of the H\alpha-emitting periphery.Comment: Accepted to A&A, 6 pages, 4 figure

Vertical distribution of ozone and VOCs in the low boundary layer of Mexico City

International audienceThe evolution of ozone and 13 volatile organic compounds (VOCs) in the boundary layer of Mexico City was investigated during 2000?2004 to improve our understanding of the complex interactions between those trace gases and meteorological variables, and their influence on the air quality of a polluted megacity. A tethered balloon, fitted with electrochemical and meteorological sondes, was used to obtain detailed vertical profiles of ozone and meteorological parameters up to 1000 m above ground during part of the diurnal cycle (02:00?18:00 h). VOCs samples were collected up to 200 m by pumping air to canisters with a Teflon tube attached to the tether line. Overall, features of these profiles were found to be consistent with a simple picture of nighttime trapping of ozone in an upper residual layer and of VOCs in a shallow unstable layer above the ground. After sunrise an ozone balance is determined by photochemical production, entrainment from the upper residual layer and destruction by titration with NO, delaying the ground-level ozone rise by 2 h. The subsequent evolution of the conductive boundary layer and vertical distribution of pollutants are discussed in terms of the energy balance, the presence of turbulence and the atmospheric stability