1,277 research outputs found
Auto-consistent metallicity and star formation history of the nearest blue compact dwarf galaxy NGC 6789
We present a detailed auto-consistent study of the nearest blue compact dwarf
galaxy NGC 6789 by means of optical and UV archive photometry data and optical
long-slit ISIS-WHT spectroscopy observations of the five brightest star-forming
knots. The analysis of the spectra in all knots allowed the derivation of ionic
chemical abundances of oxygen, nitrogen, sulphur, argon and neon using measures
of both the high- and low-excitation electron temperatures, leading to the
conclusion that NGC 6789 is chemically homogeneous with low values of the
abundance of oxygen in the range 12+log(O/H) = 7.80-7.93, but presenting at the
same time higher values of the nitrogen-to-oxygen ratio than expected for its
metal regime.
We used archival HST/WFPC2 F555W and F814W observations of NGC 6789 to
perform a photometric study of the colour-magnitude diagram (CMD) of the
resolved stellar populations and derive its star formation history (SFH), which
is compatible with the presence of different young and old stellar populations
whose metallicities do not necessarily increase with age. We fit the observed
optical spectrum in all the five knots using the STARLIGHT code and a
combination of single stellar populations following the SFH obtained from the
CMD. We compare the resulting stellar masses and the relative fractions of the
ionising populations with a non-constrained SFH case. The properties of the
younger populations were obtained using CLOUDY photoionisation models, giving
similar ages in all the knots in the range 3-6 Myr and the estimation of the
dust absorption factor, which correlates with the observed GALEX FUV-NUV colour
indices. The total photometric extinction and dust-absorption corrected
H\alpha\ fluxes were finally used to derive the star formation rates.Comment: 18 pages, 6 figures, 10 tables; accepted by MNRA
Arnaldi de Villanova compilacio de concepcione. Study and critic edition
Se establece en este trabajo la primera edición crítica de este breve tratado de Arnaldo de Vilanova, según los manuscritos existentes, que se enmarca dentro de la tipología de los tacuina y que constituye la primera monografía medieval dedicada a la esterilidad Es un texto clave para la literatura de similar temática.After reviewing the extant manuscripts, we offer the first critical edition of Arnaldo Vilanova's Compilado de Concepcione. It falls within the medical category of tacuina. It is the first medieval monography devoted to sterility, thus becoming a key text among works of similar content
Debt sustainability and procyclical fiscal policies in Latin America
The computation of structural primary balances for the nine main Latin American countries and their comparison of their changes with their cyclical position during the period 1981-2004 confirms that fiscal policy is procyclical in the region. From this evidence, the paper shows strong evidence that the fiscal behaviour is closely linked to the financial vulnerability position of the economies and in particular to the perception on the sustainability of debt. The current threshold balance, defined as the primary balance which would render the debt stable under the existing economic and financial conditions, is used as our gauge for measuring debt sustainability at each point in time. The empirical analysis reveals that the fiscal stance tightens when the debt sustainability perceptions worsen, and that this effect is stronger the less sustainable debt is perceived. The results are robust to different specifications and estimation methods. [resumen de autor
Asociación de la actividad alfa-amilasa salivar matutina con índices de psicopatología internalizante en niñas de 8-11 años
ANTECEDENTES: Recientemente, se ha observado una reducción estadísticamente significativa en los niveles de actividad de la alfa-amilasa salivar en mujeres adolescentes diagnosticadas de depresión mayor (Cubala & Landowski, 2014). OBJETIVO: El objetivo del presente estudio ha sido analizar la relación entre índices de psicopatología internalizada y niveles matutinos de cortisol, de alfa-amilasa salivar y de sus respectivos ratios (cortisol/alfa-amilasa y alfa-amilasa/cortisol) en 45 niños y 55 niñas procedentes de una muestra normativa de edades comprendidas entre los 8 y los 11 años de edad. MÉTODO: Los tutores de los 100 niños participantes en nuestro estudio rellenaron la prueba Teachers Report Forms (TRF) que permitió evaluar la presencia de sintomatología psicopatológica internalizante (escalas de ansiedad, depresión y trastornos somáticos). Se determinaron los niveles de cortisol (C) libre y de actividad de la alfa-amilasa salivar (AAAs) al despertar y a los 30 minutos durante dos días de colegio. RESULTADOS: El análisis estadístico mostró que las puntuaciones en la escala de depresión mostraban una asociación negativa con los niveles medios de la AAAs en niñas. Se observó también una asociación positiva entre las escalas de ansiedad, depresión y psicopatología internalizante y la ratio C/AAAs. Los análisis de regresión indicaron que la AAAs representaba el mejor predictor de las puntuaciones en depresión en niñas. CONCLUSIONES: Este es el primer estudio en el que, en línea con el estudio de Cubala & Landowski (2014), se describe el valor predictivo de los niveles de la AAAs matutina sobre los niveles de sintomatología depresiva en niñas procedentes de una muestra normativa.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
La recreación literaria de la historia: Escipión el Africano de Ross Leckie
The object of this study is to analyse the literary tecnique used by Ross Leckie to compose the historical novel Scipio, focusing this analysis on the relation between history and literary fiction
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