A Possible Explanation for the Size Difference of Red and Blue Globular Clusters

Most observations of the projected half-light radii of metal-rich globular clusters in a variety of galaxies have shown them to be ~20% smaller than those of their metal-poor counterparts. We show using multi-mass isotropic Michie-King models that the combined effects of mass segregation and the dependence of main sequence lifetimes on metallicity can account for this difference, under the assumption that clusters with similar central potentials have the same distribution of half mass radii. If confirmed, this would represent a new constraint on theories of globular cluster formation and evolution.Comment: 5 pages, 3 figures. Accepted for publication in ApJ Letter

The ACS Fornax Cluster Survey VII. Half-Light Radii of Globular Clusters in Early-Type Galaxies

We measure the half-light radii of globular clusters (GCs) in 43 galaxies from the ACS Fornax Cluster Survey (ACSFCS). We use these data to extend previous work in which the environmental dependencies of the half-light radii of GCs in early type galaxies in the ACS Virgo Cluster Survey (ACSVCS) were studied, and a corrected mean half-light radius (corrected for the observed environmental trends) was suggested as a reliable distance indicator. This work both increases the sample size for the study of the environmental dependencies, and adds leverage to the study of the corrected half-light radius as a possible distance indicator (since Fornax lies at a larger distance than the Virgo cluster). We study the environmental dependencies of the size of GCs using both a Principal Component Analysis as well as 2D scaling relations. We largely confirm the environmental dependencies shown in Jordan et al. (2005), but find evidence that there is a residual correlation in the mean half-light radius of GC systems with galaxy magnitude, and subtle differences in the other correlations - so there may not be a universal correction for the half-light radii of lower luminosity galaxy GC systems. The main factor determining the size of a GC in an early type galaxy is the GC color. Red GCs have = 2.8+/-0.3 pc, while blue GCs have = 3.4+/-0.3 pc. We show that for bright early-type galaxies (M_B < -19 mag), the uncorrected mean half-light radius of the GC system is by itself an excellent distance indicator (with error ~11%), having the potential to reach cosmologically interesting distances in the era of high angular resolution adaptive optics on large optical telescopes.Comment: ApJ in press, 19 pages, 16 figures

The ACS Fornax Cluster Survey. III. Globular Cluster Specific Frequencies of Early-Type Galaxies

The globular cluster (GC) specific frequency ($S_N$), defined as the number of GCs per unit galactic luminosity, represents the efficiency of GC formation (and survival) compared to field stars. Despite the naive expectation that star cluster formation should scale directly with star formation, this efficiency varies widely across galaxies. To explore this variation we measure the z-band GC specific frequency ($S_{N,z}$) for 43 early-type galaxies (ETGs) from the Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) Fornax Cluster Survey. Combined with the homogenous measurements of $S_{N,z}$ in 100 ETGs from the HST/ACS Virgo Cluster Survey from Peng et al. (2008), we investigate the dependence of $S_{N,z}$ on mass and environment over a range of galaxy properties. We find that $S_{N,z}$ behaves similarly in the two galaxy clusters, despite the clusters' order-of-magnitude difference in mass density. The $S_{N,z}$ is low in intermediate-mass ETGs ($-20<M_z<-23$), and increases with galaxy luminosity. It is elevated at low masses, on average, but with a large scatter driven by galaxies in dense environments. The densest environments with the strongest tidal forces appear to strip the GC systems of low-mass galaxies. However, in low-mass galaxies that are not in strong tidal fields, denser environments correlate with enhanced GC formation efficiencies. Normalizing by inferred halo masses, the GC mass fraction, $\eta=(3.36\pm0.2)\times10^{-5}$, is constant for ETGs with stellar masses $\mathcal{M}_\star \lesssim 3\times10^{10}M_\odot$, in agreement with previous studies. The lack of correlation between the fraction of GCs and the nuclear light implies only a weak link between the infall of GCs and the formation of nuclei.Comment: 16 pages, 7 figures, 6 tables; accepted by Ap

Efectividad del marketing de influencers para posicionar pymes dedicadas a la venta de prendas de vestir en Guayaquil

El artículo pretende analizar la efectividad del marketing de influencers y dar recomendaciones a las pymes que la utilizan. Para esto se investigó diferentes teorías como la conductista de Skinner y la psicológica social de Veblen, entre otras. Así se logró establecer el perfil demográfico adecuado del influencer que las empresas deben utilizarThis article aims to analyze the effectiveness of influencer marketing and give recommendations to SMEs that use it. For this, different theories such as Skinner's behaviorist and Veblen's social psychological, among others, were investigated. This was possible to establish the appropriate demographic profile of the influencer that companies must use

Evaluación del desempeño del talento humano de la compañía de producción y comercialización Mascorona & Soleg Cia. Ltda. de la ciudad de Ambato

El presente trabajo de investigación denominado, evaluación del desempeño del talento humano de la compañía de producción y comercialización Mascorona & Soleg cia. Ltda. De la ciudad de Ambato se enfocó en detectar problemas que afecten directamente al desenvolvimiento de la organización en el ámbito empresarial. Este documento contribuyó de manera eficiente y eficaz en los objetivos empresariales, esta actividad permitió la aplicación de diferentes métodos y técnicas útiles que ayudaron a extraer la información necesaria para culminar con una evaluación de desempeño, se utilizaron instrumentos tales como la encuesta, mediante la cual se determinó la necesidad de evaluar a los colaboradores de la compañía. Posteriormente con la ejecución de la evaluación se detectó deficiencias mínimas en los procesos de producción y venta, los cuales permitieron generar una matriz de estrategias, en búsqueda de la mejora continua, proyectando el cumplimiento de metas empresariales y el desarrollo personal y profesional de sus colaboradores. La investigación se lo realizó en conjunto con el jefe del departamento de Talento Humano la Ing. Ana Galarza, y la colaboración voluntaria de los empleados de la institución con los cuales se socializó el trabajo a efectuarse, finalmente se deja planteada la propuesta de un modelo de evaluación de desempeño del talento humano para aplicarse de manera periódica, además de estrategias que permitirán generar motivación, capacitación y profesionalismo en la fuerza laboral de la compañíaThe present study entitled evaluation about the performance of the human talent department of the production and marketing company Mascorona & Soleg cia. Ltda. located in Ambato city focused on detecting problems that directly affect the development of the organization in the business area. This document contributed efficiently and effectively to business objectives, this activity allowed the application of different useful methods and techniques that helped extract the necessary information to complete a performance evaluation, instruments such as the survey were used, through which the need to evaluate the company's employees was determined. Subsequently, with the execution of the evaluation, minimal deficiencies were detected in the production and sales processes, which allowed the generation of a matrix of strategies, in search of continuous improvement, projecting the fulfillment of business goals and the personal and professional development of its collaborators. . The investigation was carried out in cooperation with the head of the Human Talent Department Ms. Ana Galarza, and the voluntary collaboration of the employees of the institution with whom the work to be carried out was socialized, finally the proposal of a model performance evaluation of human talent to be applied periodically, in addition to strategies that will generate motivation, training and professionalism in the company's workforc

The ACS Fornax Cluster Survey. IX. The Color-Magnitude Relation of Globular Cluster Systems

We investigate the color-magnitude relation for globular clusters (GCs) -- the so-called "blue tilt" -- detected in the ACS Fornax Cluster Survey and using the combined sample of GCs from the ACS Fornax and Virgo Cluster Surveys. We find a tilt of gamma_z=d(g-z)/dz=-0.0257 +- 0.0050 for the full GC sample of the Fornax Cluster Survey (~5800 GCs). This is slightly shallower than the value gamma_z=-0.0459 +- 0.0048 found for the Virgo Cluster Survey GC sample (~11100 GCs). The slope for the merged Fornax and Virgo datasets (~16900 GCs) is gamma_z=-0.0293 +- 0.0085, corresponding to a mass-metallicity relation of Z ~ M^0.43. We find that the blue tilt sets in at GC masses in excess of M ~ 2*10^5 M_sun. The tilt is stronger for GCs belonging to high-mass galaxies (M_* > 5 * 10^10 M_sun) than for those in low-mass galaxies (M_* < 5 * 10^10 M_sun). It is also more pronounced for GCs with smaller galactocentric distances. Our findings suggest a range of mass-metallicity relations Z_GC ~ M_GC^(0.3-0.7) which vary as a function of host galaxy mass/luminosity. We compare our observations to a recent model of star cluster self-enrichment with generally favorable results. We suggest that, within the context of this model, the proto-cluster clouds out of which the GCs formed may have had density profiles slightly steeper than isothermal and/or star formation efficiencies somewhat below 0.3. We caution, however, that the significantly different appearance of the CMDs defined by the GC systems associated with galaxies of similar mass and morphological type pose a challenge to any single mechanism that seeks to explain the blue tilt. We therefore suggest that the merger/accretion histories of individual galaxies have played a non-negligible role determining the distribution of GCs in the CMDs of individual GC systems