TESIS PARA OPTAR AL GRADO DE MAGÍSTER EN FINANZAS
El presente documento tuvo por objetivo principal la valoración económica del patrimonio perteneciente a la empresa Autoterm S.A., sociedad anónima ...cerrada, cuyo giro corresponde al de Montajes Industriales e Integración Tecnológica. Sus principales clientes pertenecen a la gran industria, participando en rubros como Minería, Telecomunicaciones y Forestal.;
Tras un análisis de la estructura de capital de la empresa, se obtuvo una razón de endeudamiento (B/V) de 0.4, una razón de patrimonio (P/B) de 0.6, y una razón deuda patrimonio (B/P) de 0.67.;
Posteriormente se realiza un estudio respecto a las metodologías comúnmente utilizadas para la valoración de empresas, en donde se analizan ventajas y desventajas en su aplicación a empresas pequeñas y medianas, que no cotizan en mercados de referencia de manera regular. Se concluye que la metodología de valorización mediante flujos de caja descontados (DCF) es la que mejor se acomoda a la estructura e información disponible para la empresa Autoterm S.A..;
Considerando la metodología seleccionada, se procede a estimar el riesgo del negocio utilizando como referencia la empresa Salfacorp, en particular su filial “Ingeniería y Construcción S.A.”, debido a las similitudes en cuanto a rubros de referencia, segmentación de clientes y crecimientos patrimoniales. El riesgo (beta) estimado para el negocio asciende a 1.91 en el periodo evaluado.;
Tras la obtención del Beta del negocio, se procede a estimar mediante WACC el costo de capital de la empresa Autoterm, el cual asciende a 15,93%, considerando en este valor una prima por iliquidez del 3%.;
Con el costo de capital estimado, se procede a la proyección de los EERR asociados a la empresa Autoterm, los cuales conforman la base para el cálculo del Flujo de Caja Libre (FCL). El FCL proyectado se descuenta a tasa de costo de capital, permitiendo estimar el valor de los activos operativos de la empresa. Ajustando las cuentas no operativas y capital de trabajo, se obtiene finalmente un valor para el patrimonio económico de 69.035 UF utilizando un criterio a crecimientos históricos, y 120.122 UF al ajustar por proyecciones entregadas por el directorio.
The disk mass is among the most important input parameter for every planet formation model to determine the number and masses of the planets that can form. We present an ALMA 887micron survey of the ...disk population around objects from 2 to 0.03Msun in the nearby 2Myr-old Chamaeleon I star-forming region. We detect thermal dust emission from 66 out of 93 disks, spatially resolve 34 of them, and identify two disks with large dust cavities of about 45AU in radius. Assuming isothermal and optically thin emission, we convert the 887micron flux densities into dust disk masses, hereafter Mdust. We find that the Mdust-Mstar relation is steeper than linear with power law indices 1.3-1.9, where the range reflects two extremes of the possible relation between the average dust temperature and stellar luminosity. By re-analyzing all millimeter data available for nearby regions in a self-consistent way, we show that the 1-3 Myr-old regions of Taurus, Lupus, and Chamaeleon I share the same Mdust-Mstar relation, while the 10Myr-old Upper Sco association has a steeper relation. Theoretical models of grain growth, drift, and fragmentation reproduce this trend and suggest that disks are in the fragmentation-limited regime. In this regime millimeter grains will be located closer in around lower-mass stars, a prediction that can be tested with deeper and higher spatial resolution ALMA observations.
Over the duration of the Kepler mission, KIC8462852 was observed to undergo irregularly shaped, aperiodic dips in flux of up to \(\sim 20\)\%. The dipping activity can last for between 5 and 80 days. ...We characterize the object with high-resolution spectroscopy, spectral energy distribution fitting, radial velocity measurements, high-resolution imaging, and Fourier analyses of the Kepler light curve. We determine that KIC8462852 is a typical main-sequence F3 V star that exhibits no significant IR excess, and has no very close interacting companions. In this paper, we describe various scenarios to explain the dipping events observed in the Kepler light curve. We confirm that the dipping signals in the data are not caused by any instrumental or data processing artifact, and thus are astrophysical in origin. We construct scenario-independent constraints on the size and location of a body in the system that is needed to reproduce the observations. We deliberate over several assorted stellar and circumstellar astrophysical scenarios, most of which have problems explaining the data in hand. By considering the observational constraints on dust clumps in orbit around a normal main-sequence star, we conclude that the scenario most consistent with the data in hand is the passage of a family of exocomet or planetesimal fragments, all of which are associated with a single previous break-up event, possibly caused by tidal disruption or thermal processing. The minimum total mass associated with these fragments likely exceeds \(10^{-6}\)~\mearth, corresponding to an original rocky body of \(>100\)~km in diameter. We discuss the necessity of future observations to help interpret the system.
The disk mass is among the most important input parameter for every planet formation model to determine the number and masses of the planets that can form. We present an ALMA 887 mu m survey of the ...disk population around objects from similar to 2 to 0.03 M-circle dot in the nearby similar to 2 Myr old Chamaeleon I star-forming region. We detect thermal dust emission from 66 out of 93 disks, spatially resolve 34 of them, and identify two disks with large dust cavities of about 45 au in radius. Assuming isothermal and optically thin emission, we convert the 887 mu m flux densities into dust disk masses, hereafter M-dust. We find that the M-dust-M* relation is steeper than linear and of the form M-dust proportional to (M*)(1.3-1.9), where the range in the power-law index reflects two extremes of the possible relation between the average dust temperature and stellar luminosity. By reanalyzing all millimeter data available for nearby regions in a self-consistent way, we show that the 1-3 Myr old regions of Taurus, Lupus, and Chamaeleon. I share the same M-dust-M* relation, while the 10 Myr old Upper. Sco association has a steeper relation. Theoretical models of grain growth, drift, and fragmentation reproduce this trend and suggest that disks are in the fragmentation-limited regime. In this regime millimeter grains will be located closer in around lower-mass stars, a prediction that can be tested with deeper and higher spatial resolution ALMA observations.
ABSTRACT
Code Investigating GALaxy Emission (cigale) is a powerful multiwavelength spectral energy distribution (SED) fitting code for extragalactic studies. However, the current version of cigale is ...not able to fit X-ray data, which often provide unique insights into active galactic nucleus (AGN) intrinsic power. We develop a new X-ray module for cigale, allowing it to fit SEDs from the X-ray to infrared (IR). We also improve the AGN fitting of cigale from UV-to-IR wavelengths. We implement a modern clumpy two-phase torus model, skirtor. To account for moderately extincted type 1 AGNs, we implement polar-dust extinction. We publicly release the source code (named ‘x-cigale’). We test x-cigale with X-ray detected AGNs in SDSS, COSMOS, and AKARI-NEP. The fitting quality (as indicated by reduced χ2) is good in general, indicating that x-cigale is capable of modelling the observed SED from X-ray to IR. We discuss constrainability and degeneracy of model parameters in the fitting of AKARI-NEP, for which excellent mid-IR photometric coverage is available. We also test fitting a sample of AKARI-NEP galaxies for which only X-ray upper limits are available from Chandra observations, and find that the upper limit can effectively constrain the AGN SED contribution for some systems. Finally, using x-cigale, we assess the ability of Athena to constrain the AGN activity in future extragalactic studies.
Aims. We use high-resolution continuum images obtained with the Atacama Large Millimeter Array (ALMA) to probe the surface density of star formation in z ~ 2 galaxies and study the different physical ...properties between galaxies within and above the star-formation main sequence of galaxies. Methods. We use ALMA images at 870 μm with 0.2 arcsec resolution in order to resolve star formation in a sample of eight star-forming galaxies at z ~ 2 selected among the most massive Herschel galaxies in the GOODS-South field. This sample is supplemented with eleven galaxies from the public data of the 1.3 mm survey of the Hubble Ultra-Deep Field, HUDF. We derive dust and gas masses for the galaxies, compute their depletion times and gas fractions, and study the relative distributions of rest-frame ultraviolet (UV) and far-infrared (FIR) light. Results. ALMA reveals systematically dense concentrations of dusty star formation close to the center of the stellar component of the galaxies. We identify two different starburst regimes: (i) the classical population of starbursts located above the SFR-M⋆ main sequence, with enhanced gas fractions and short depletion times and (ii) a sub-population of galaxies located within the scatter of the main sequence that experience compact star formation with depletion timescales typical of starbursts of ~150 Myr. In both starburst populations, the FIR and UV are distributed in distinct regions and dust-corrected star formation rates (SFRs) estimated using UV-optical-near-infrared data alone underestimate the total SFR. Starbursts hidden in the main sequence show instead the lowest gas fractions of our sample and could represent the last stage of star formation prior to passivization. Being Herschel-selected, these main sequence galaxies are located in the high-mass end of the main sequence, hence we do not know whether these “starbursts hidden in the main sequence” also exist below 1011 M⊙. Active galactic nuclei (AGNs) are found to be ubiquitous in these compact starbursts, suggesting that the triggering mechanism also feeds the central black hole or that the active nucleus triggers star formation.
Aims. In this work, we aim to provide a consistent analysis of the dust properties from metal-poor to metal-rich environments by linking them to fundamental galactic parameters. Methods. We consider ...two samples of galaxies: the Dwarf Galaxy Survey (DGS) and the Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel (KINGFISH), totalling 109 galaxies, spanning almost 2 dex in metallicity. We collect infrared (IR) to submillimetre (submm) data for both samples and present the complete data set for the DGS sample. We model the observed spectral energy distributions (SED) with a physically-motivated dust model to access the dust properties: dust mass, total-IR luminosity, polycyclic aromatic hydrocarbon (PAH) mass fraction, dust temperature distribution, and dust-to-stellar mass ratio. Results. Using a different SED model (modified black body), different dust composition (amorphous carbon in lieu of graphite), or a different wavelength coverage at submm wavelengths results in differences in the dust mass estimate of a factor two to three, showing that this parameter is subject to non-negligible systematic modelling uncertainties. We find half as much dust with the amorphous carbon dust composition. For eight galaxies in our sample, we find a rather small excess at 500 μm (≤1.5σ). We find that the dust SED of low-metallicity galaxies is broader and peaks at shorter wavelengths compared to more metal-rich systems, a sign of a clumpier medium in dwarf galaxies. The PAH mass fraction and dust temperature distribution are found to be driven mostly by the specific star formation rate, sSFR, with secondary effects from metallicity. The correlations between metallicity and dust mass or total-IR luminosity are direct consequences of the stellar mass-metallicity relation. The dust-to-stellar mass ratios of metal-rich sources follow the well-studied trend of decreasing ratio for decreasing sSFR. The relation is more complex for low-metallicity galaxies with high sSFR, and depends on the chemical evolutionary stage of the source (i.e. gas-to-dust mass ratio). Dust growth processes in the ISM play a key role in the dust mass build-up with respect to the stellar content at high sSFR and low metallicity. Conclusions. We conclude that the evolution of the dust properties from metal-poor to metal-rich galaxies derives from a complex interplay between star formation activity, stellar mass, and metallicity.
Prevention of Depressive Symptoms in Adolescents Horowitz, Jason L; Garber, Judy; Ciesla, Jeffrey A ...
Journal of consulting and clinical psychology,
10/2007, Letnik:
75, Številka:
5
Journal Article
Recenzirano
This study evaluated the efficacy of 2 programs for preventing depressive symptoms in adolescents. Participants were 380 high school students randomly assigned to a cognitive-behavioral program (CB), ...an interpersonal psychotherapy-adolescent skills training program (IPT-AST), or a no-intervention control. The interventions involved eight 90-min weekly sessions run in small groups during wellness classes. At postintervention, students in both the CB and IPT-AST groups reported significantly lower levels of depressive symptoms than did those in the no-intervention group, controlling for baseline depression scores; the 2 intervention groups did not differ significantly from each other. The effect sizes, using Cohen's
d
, for the CB intervention and the IPT-AST intervention were 0.37 and 0.26, respectively. Differences between control and intervention groups were largest for adolescents with high levels of depressive symptoms at baseline. For a high-risk subgroup, defined as having scored in the top 25th percentile on the baseline depression measure, the effect sizes for the CB and the IPT-AST interventions were 0.89 and 0.84, respectively. For the whole sample, sociotropy and achievement orientation moderated the effect of the interventions. Intervention effects were short term and were not maintained at 6-month follow-up.
Context.
Radio used as a tracer of the star formation rate (SFR) presents enormous advantages because it is not affected by dust and radio sources that are located at the subarcsecond level. The ...interpretation of the low-frequency 1.4 GHz luminosity is hampered by the difficulty of modeling the paths of cosmic rays in the interstellar medium, however, and by their interactions with the magnetic field.
Aims.
We compare the SFR derived from radio observations and the SFRs derived from spectral energy distribution (SED) modeling. We aim at better understanding the behavior of the SFR radio tracer, with a specific emphasis on the link to star formation histories (SFHs).
Methods.
The analysis is based on a subsample of 1584 star-forming galaxies extracted from the Cosmic Evolution Survey (COSMOS) with observations of the Very large array project at 3 GHz. We used the SED modeling code investigating galaxy emission,
CIGALE
, with a nonparametric model for the SFH and fit the data over the wavelength range from the ultraviolet (UV) to the mid-infrared (mid-IR). We interpret the difference between radio and SED-based SFR tracers in the light of recent gradients in the derived SFH. To validate the robustness of the results, we searched for any remaining contribution of active galaxy nuclei and tested the impact of our SFH modeling approach.
Results.
Approximately 27% our galaxies present a radio SFR (SFR
radio
) that is at least ten times higher than the instantaneous SFR from SED fitting (SFR
SED
). This trend primarily affects the galaxies whose SFH activity decreased over the last 300 Myr. Both SFR indicators converge toward a consistent value when the SFHs are averaged over a period longer than 150 Myr to derive SFR
SED
.
Conclusions.
Although the radio at a low frequency of 1.4 GHz is a good tracer of the star formation activity of galaxies with a constant or increasing SFH, our results indicate that this is not the case for quenched galaxies. Our analysis suggests that the star formation time sensitivity of the low radio frequency might be longer than 150 Myr. Interestingly, the discrepancy between the SFR
radio
and SFR
SED
can be used as diagnostic to select post-starburst galaxies.
Submillimeter/millimeter observations of dusty star-forming galaxies with the Atacama Large Millimeter/submillimeter Array (ALMA) have shown that dust continuum emission generally occurs in compact ...regions smaller than the stellar distribution. However, it remains to be understood how systematic these findings are. Studies often lack homogeneity in the sample selection, target discontinuous areas with inhomogeneous sensitivities, and suffer from modest
u
v
coverage coming from single array configurations. GOODS-ALMA is a 1.1 mm galaxy survey over a continuous area of 72.42 arcmin
2
at a homogeneous sensitivity. In this version 2.0, we present a new low resolution dataset and its combination with the previous high resolution dataset from the survey, improving the
u
v
coverage and sensitivity reaching an average of
σ
= 68.4 μJy beam
−1
. A total of 88 galaxies are detected in a blind search (compared to 35 in the high resolution dataset alone), 50% at
S
/
N
peak
≥ 5 and 50% at 3.5 ≤
S
/
N
peak
≤ 5 aided by priors. Among them, 13 out of the 88 are optically dark or faint sources (
H
- or
K
-band dropouts). The sample dust continuum sizes at 1.1 mm are generally compact, with a median effective radius of
R
e
= 0
.
″
10 ± 0
.
″
05 (a physical size of
R
e
= 0.73 ± 0.29 kpc at the redshift of each source). Dust continuum sizes evolve with redshift and stellar mass resembling the trends of the stellar sizes measured at optical wavelengths, albeit a lower normalization compared to those of late-type galaxies. We conclude that for sources with flux densities
S
1.1 mm
> 1 mJy, compact dust continuum emission at 1.1 mm prevails, and sizes as extended as typical star-forming stellar disks are rare. The
S
1.1 mm
< 1 mJy sources appear slightly more extended at 1.1 mm, although they are still generally compact below the sizes of typical star-forming stellar disks.
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