Galaxy Light Concentration. I. Index stability and the connection with galaxy structure, dynamics, and supermassive black holes

We explore the stability of different galaxy light concentration indices as a function of the outermost observed galaxy radius. With a series of analytical light-profile models, we show mathematically how varying the radial extent to which one measures a galaxy's light can strongly affect the derived galaxy concentration. The "mean concentration index", often used for parameterizing high-redshift galaxies, is shown to be horribly unstable, even when modeling one-component systems such as elliptical, dwarf elliptical and pure exponential disk galaxies. The C_31 concentration index performs considerably better but is also heavily dependent on the radial extent, and hence exposure depth, of any given galaxy. We show that the recently defined central concentration index is remarkably stable against changes to the outer radius, providing a meaningful and reliable estimate of galaxy concentration. The index n from the r^(1/n) models is shown to be monotonically related with the central concentration of light, giving the index n a second and perhaps more tangible meaning. With a sample of elliptical and dwarf elliptical galaxies, we present correlations between the central light concentration and the global parameters: luminosity (Pearson's r = -0.82), effective radius (r = 0.67), central surface brightness (r = -0.88), and velocity dispersion (r = 0.80). The more massive elliptical galaxies are shown to be more centrally concentrated. We speculate that the physical mechanism behind the recently observed correlation between the central velocity dispersion (mass) of a galaxy and the mass of its central supermassive black hole may be connected with the central galaxy concentration. That is, we hypothesize that it may not simply be the amount of mass in a galaxy but rather how that mass is distributed that controls the mass of the central black hole.Comment: (aastex, 18 pages including 13 figures

A correlation between light profile and [Mg/Fe] abundance ratio in early-type galaxies

We explore possible correlations between light profile shapes, as parameterized by the Sersic index or the concentration index C_re(1/3), and relevant stellar population parameters in early-type galaxies. Mean luminosity weighted ages, metallicities and abundance ratios were obtained from spectra of very high signal-to-noise and stellar population models that synthesize galaxy spectra at the resolution given by their velocity dispersions, in combination with an age indicator that is virtually free of the effects of metallicity. We do not find any significant correlation between the Sersic index (or C_re(1/3)) and mean age or metallicity, but a strong positive correlation of the shape parameters with [Mg/Fe] abundance ratio. This dependence is as strong as the [Mg/Fe] vs. velocity dispersion and C_re(1/3) vs. velocity dispersion relations. We speculate that early-type galaxies settle up their structure on time-scales in agreement with those imposed by their [Mg/Fe] ratios. This suggest that the global structure of larger galaxies, with larger [Mg/Fe] ratios and shorter time-scales, was already at place at high z, without experiencing a significant time evolution.Comment: 5 pages, 3 figures (to appear in The Astrophysical Journal Letters

Inclusivity of Minorities in the U.S. Healthcare System

Throughout the evolution of U.S. healthcare, the inclusivity of minorities has been a discussion amongst many communities. With healthcare being unaffordable and inaccessible to many, including minorities, it can influence their responses towards it. From research and in-depth observations, it has been revealed that certain ethnicities carry a trend of disabling illnesses and infectious diseases. This paper intends to identify the patterns that occur amongst ethnic communities that increase the risk of obtaining these conditions. Social determinants govern the health and lifestyle that have led to life-threatening illnesses. It has been found that factors such as eating habits, social environments, financial restraints, and traditional practices have been a part of reoccurring illnesses amongst minorities. However, studies have revealed that they do not seek treatment as much as white Americans do. A common reason for this is that many minorities are likely to not possess health insurance due to their financial restraints. Under the circumstances, options to seek insurance and treatment are limited. The inability to afford coverage and proper care can influence their attitudes towards healthcare. This paper will explore obstacles that ethnic communities are confronted with and create a plan to overcome them for the benefit of their health

A Correlation between Galaxy Light Concentration and Supermassive Black Hole Mass

We present evidence for a strong correlation between the concentration of bulges and the mass of their central supermassive black hole (M_bh) -- more concentrated bulges have more massive black holes. Using C_{r_e}(1/3) from Trujillo, Graham & Caon (2001b) as a measure of bulge concentration, we find that log (M_bh/M_sun) = 6.81(+/-0.95)C_{r_e}(1/3) + 5.03(+/-0.41). This correlation is shown to be marginally stronger (Spearman's r_s=0.91) than the relationship between the logarithm of the stellar velocity dispersion and log M_bh (Spearman's r_s=0.86), and has comparable, or less, scatter (0.31 dex in log M_bh), which decreases to 0.19 dex when we use only those galaxies whose supermassive black hole's radius of influence is resolved and remove one well understood outlying data point).Comment: 7 pages, 1 table, 2 figures. ApJ Letters, accepte

A Substantial Amount of Hidden Magnetic Energy in the Quiet Sun

Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal heating. At present, we can see only ${\sim}1$ of the complex magnetism of the quiet Sun, which highlights the need to develop a reliable way to investigate the remaining 99%. Here we report three-dimensional radiative tranfer modelling of scattering polarization in atomic and molecular lines that indicates the presence of hidden, mixed-polarity fields on subresolution scales. Combining this modelling with recent observational data we find a ubiquitous tangled magnetic field with an average strength of ${\sim}130$ G, which is much stronger in the intergranular regions of solar surface convection than in the granular regions. So the average magnetic energy density in the quiet solar photosphere is at least two orders of magnitude greater than that derived from simplistic one-dimensional investigations, and sufficient to balance radiative energy losses from the solar chromosphere.Comment: 21 pages and 2 figures (letter published in Nature on July 15, 2004

An?lisis de las pr?cticas y los estilos pedag?gicos de los docentes de la instituci?n educativa Ricabrisa de Tarqui, Huila y su relaci?n con los resultados en las pruebas externas saber

128 P?ginasRecurso Electr?nicoEl presente trabajo refiere a los resultados de un estudio cualitativo cuyo objetivo fue el analizar las pr?cticas y los estilos pedag?gicos de un grupo de docentes de b?sica secundaria que se desempe?an en las ?reas de lenguaje, ciencias naturales y matem?ticas evaluadas en pruebas externas saber en el a?o 2009 de la Instituci?n Educativa Ricabrisa de Tarqui Huila. La investigaci?n se hace utilizando como herramientas la observaci?n in situ y el grupo focal. Aporta la descripci?n de las caracter?sticas de las pr?cticas docentes y el reconocimiento de sus concepciones en las categor?as de la investigaci?n, as? como sus tendencias pedag?gicas. El trabajo finaliza determinando la incidencia y el impacto de pr?cticas y estilos pedag?gicos en los resultados en pruebas externas saber.ABSTRACT. The present work refers to the results of a qualitative study which objective was to analyze the practices and teaching styles of a group of middle school teachers who work in the area of humanities, natural sciences and mathematics, evaluated in external Saber test in 2009 of Instituci?n Educativa Ricabrisa, Tarqui Huila. The research is done using tools as in situ observation and focal groups. It provides the description of the characteristics of teaching practices and recognition of their conceptions in the categories of research and pedagogical trends. The work ends by determining the incidence and the impact of practice and teaching styles in the results in external Saber tests.INTRODUCCI?N 13 1. PLANTEAMIENTO Y FORMULACI?N DEL PROBLEMA 16 2. OBJETIVOS 19 2.1 OBJETIVO GENERAL 19 2.2 OBJETIVOS ESPEC?FICOS 19 3. JUSTIFICACI?N 20 4. ESTADO DEL ARTE 22 5. REFERENTES TE?RICOS 37 5.1 REFLEXI?N SOBRE ESTILOS PEDAG?GICOS 37 5.1.1 Desde el inter?s emancipatorio (Estilo 1) 44 5.1.2 Desde el inter?s t?cnico (Estilo 2) 45 5.1.3 Desde el inter?s pr?ctico (Estilo 3) 46 5.2 SOBRE LAS PR?CTICAS PEDAG?GICAS 47 5.2.1 Pr?cticas expositivas 48 5.2.2 Pr?cticas constructivas 50 5.2.3. Pr?cticas L?dicas 55 5.3. PRUEBAS EXTERNAS NACIONALES ?SABER? 56 6. METODOLOG?A 60 6.1 TIPO DE INVESTIGACI?N 62 6.2 DISE?O DE LA INVESTIGACI?N 62 6.3 POBLACI?N Y MUESTRA 62 6.4. UNIDADES DE AN?LISIS 62 6.5 INSTRUMENTOS Y TECNICAS APLICADAS 63 6.6. PLAN DE AN?LISIS 64 6.6.1 An?lisis de informaci?n 64 7. ANALISIS DE RESULTADOS 65 7.1 TRIANGULACI?N DE DATOS 74 7.2 AN?LISIS COMPARATIVO DE LAS ?REAS EVALUADAS 82 8. CONCLUSIONES 86 REFERENCIAS BIBLIOGR?FICAS 88 ANEXOS 9

Collocation and Pattern Recognition Effects on System Failure Remediation

Previous research found that operators prefer to have status, alerts, and controls located on the same screen. Unfortunately, that research was done with displays that were not designed specifically for collocation. In this experiment, twelve subjects evaluated two displays specifically designed for collocating system information against a baseline that consisted of dial status displays, a separate alert area, and a controls panel. These displays differed in the amount of collocation, pattern matching, and parameter movement compared to display size. During the data runs, subjects kept a randomly moving target centered on a display using a left-handed joystick and they scanned system displays to find a problem in order to correct it using the provided checklist. Results indicate that large parameter movement aided detection and then pattern recognition is needed for diagnosis but the collocated displays centralized all the information subjects needed, which reduced workload. Therefore, the collocated display with large parameter movement may be an acceptable display after familiarization because of the possible pattern recognition developed with training and its use

Conversational eyebrow frowns facilitate question identification: An online VR study

Conversation is a time-pressured environment. Recognising a social action (the ‘speech act’, such as a question requesting information) early is crucial in conversation to quickly understand the intended message and plan a timely response. Fast turns between interlocutors are especially relevant for responses to questions, since a long gap may be meaningful by itself. Human language is multimodal, involving speech as well as visual signals from the body, including the face. But little is known about how conversational facial signals contribute to the communication of social actions. Some of the most prominent facial signals in conversation are eyebrow movements. Previous studies found links between eyebrow movements and questions, suggesting that these facial signals could contribute to the rapid recognition of questions. Therefore, we aimed to investigate whether early eyebrow movements (eyebrow frown or raise vs. no eyebrow movement) facilitate question identification. Participants were instructed to view videos of avatars where the presence of eyebrow movements accompanying questions was manipulated. Their task was to indicate whether the utterance was a question or a statement as accurately and quickly as possible. Data was collected using the online testing platform Gorilla. Results showed higher accuracies and faster response times for questions with eyebrow frowns, suggesting a facilitative role of eyebrow frowns for question identification. This means that facial signals can critically contribute to the communication of social actions in conversation by signaling social action-specific visual information, and provide visual cues to speakers’ intentions