Spectral Indices of Stars at Super-solar Regime

We derived Lick narrow-band indices for 139 candidate super metal-rich stars of different luminosity class previously studied in Malagnini et al. (2000). Indices include Iron Fe50, Fe52, Fe53, and Magnesium Mgb and Mg2 features. By comparing observations with Kurucz' synthetic model atmospheres, no evidence is found for non-standard Mg vs. Fe relative abundance (i.e. [Mg/Fe]~ 0, on the average, for our sample). A comparison with the Worthey et al.(1994) and Buzzoni et al.(1992, 1994) fitting function predictions for [Fe/H] > 0 is performed and briefly discussed.Comment: 4 pages, 3 figures; proceedings of "New Quests in Stellar Astrophysics: The link between Stars and Cosmology", 26-30 March, 2001, Puerto Vallarta, Mexico, eds. M. Chavez, A. Bressan, A. Buzzoni & D. Mayya, to be published by the Kluwer Academic Publisher

The Optimal Pricing of Pollution When Enforcement is Costly

We consider the pricing of a uniformly mixed pollutant when enforcement is costly with a model of optimal, possibly firm-specific, emissions taxes and their enforcement. We argue that optimality requires an enforcement strategy that induces full compliance by every firm. This holds whether or not regulators have complete information about firms’ abatement costs, the costs of monitoring them for compliance, or the costs of collecting penalties from noncompliant firms. Moreover, ignoring several unrealistic special cases, optimality requires discriminatory emissions taxes except when regulators are unable to observe firms’ abatement costs, the costs of monitoring individual firms, or any firm-specific characteristic that is known to be jointly distributed with either the firms’ abatement costs or their monitoring costs. In many pollution control settings, especially those that have been subject to various forms of environmental regulation in the past, regulators are not likely to be so ill-informed about individual firms. In these settings, policies that set or generate a uniform pollution price like conventional designs involving uniform taxes and competitive emission trading with freely-allocated or auctioned permits will not be efficient.Compliance, Enforcement, Emissions Taxes, Monitoring, Asymmetric Information, Uncertainty

Crecimiento in vitro de Lactarius deliciosus en medio de cultivo BAF y MNM

- Chávez, D.; Pereira, G. ; Machuca, A. Laboratorio de Biotecnología de Hongos. Departamento Forestal, Campus Los Ángeles, Universidad de Concepción. J. A. Coloma 0201, Casilla 341. Los Ángeles-Chile.Lactarius deliciosus (L. Gray) es un hongo ectomicorrícico que crece asociado a Pinus radiata, constituyendo sus cuerpos fructíferos un producto muy apetecido desde el punto de vista gastronómico en la alta cocina. Desde esta perspectiva es un hongo que puede entregar valor agregado al bosque, siendo necesario entonces, conocer y caracterizar su comportamiento en laboratorio, y posteriormente, en las inoculaciones en viveros. En el presente estudio se aisló Lactarius deliciosus a partir de carpóforos jóvenes, recolectados de plantaciones de Pinus radiata de la Comuna de Ninhue, Provincia de Ñuble, VIII Región. Dicha cepa se caracterizó in vitro, en dos medios de cultivo sólido, Melin-Norkrans-modificado (MNM) y Aneurina-Acido fólico- Agar (BAF), incubándose a 24 ºC en oscuridad, en donde se determinó velocidad de crecimiento radial (mm/día), y en medio de cultivo líquido BAF, se evaluó crecimiento miceliar, variación del pH y determinación del consumo de azúcares en el medio. Todos los medios de cultivos empleados (sólidos y líquidos) fueron ajustados a pH 5,8. Los resultados del estudio muestran un mayor incremento en velocidad media de crecimiento radial en el medio de cultivo BAF, mostrando diferencias significativas respecto al medio de cultivo MNM. La producción de biomasa miceliar en el medio líquido aumentó progresivamente a medida que avanzaban los días de incubación, induciendo ello una disminución moderada del pH del medio de cultivo, y un aumento en el consumo de azúcar producto del crecimiento del hongo

Lick Spectral Indices for Super Metal-rich Stars

The Lick Fe5015, Fe5270, Fe5335, Mgb and Mg2 indices are presented for 139 candidate SMR stars of different luminosity class studied in Malagnini et al. (2000). Evidence is found for a standard (i.e. [Mg/Fe]~0) Mg vs. Fe relative abundance. Both the Worthey et al. (1994) and Buzzoni et al. (1992, 1994) fitting functions are found to suitably match the data at super-solar metallicity regimes. See http://www.merate.mi.astro.it/~eps/home.html for further details.Comment: 16 pages with 11 figures (Aastex format). To appear in the Nov. '01 issue of the PAS

Star Formation History and Extinction in the central kpc of M82-like Starbursts

We report on the star formation histories and extinction in the central kpc region of a sample of starburst galaxies that have similar far infrared (FIR), 10 micron and K-band luminosities as those of the archetype starburst M82. Our study is based on new optical spectra and previously published K-band photometric data, both sampling the same area around the nucleus. Model starburst spectra were synthesized as a combination of stellar populations of distinct ages formed over the Hubble time, and were fitted to the observed optical spectra and K-band flux. The model is able to reproduce simultaneously the equivalent widths of emission and absorption lines, the continuum fluxes between 3500-7000 Ang, the K-band and the FIR flux. We require a minimum of 3 populations -- (1) a young population of age < 8 Myr, with its corresponding nebular emission, (2) an intermediate-age population (age < 500 Myr), and (3) an old population that forms part of the underlying disk or/and bulge population. The contribution of the old population to the K-band luminosity depends on the birthrate parameter and remains above 60% in the majority of the sample galaxies. Even in the blue band, the intermediate age and old populations contribute more than 40% of the total flux in all the cases. A relatively high contribution from the old stars to the K-band nuclear flux is also apparent from the strength of the 4000 Ang break and the CaII K line. The extinction of the old population is found to be around half of that of the young population. The contribution to the continuum from the relatively old stars has the effect of diluting the emission equivalent widths below the values expected for young bursts. The mean dilution factors are found to be 5 and 3 for the Halpha and Hbeta lines respectively.Comment: 20 pages, uses emulateapj.cls. Scheduled to appear in ApJ Jan 1, 200

Open Issues on the Synthesis of Evolved Stellar Populations at Ultraviolet Wavelengths

In this paper we briefly review three topics that have motivated our (and others') investigations in recent years within the context of evolutionary population synthesis techniques. These are: The origin of the FUV up-turn in elliptical galaxies, the age-metallicity degeneracy, and the study of the mid-UV rest-frame spectra of distant red galaxies. We summarize some of our results and present a very preliminary application of a UV grid of theoretical spectra in the analysis of integrated properties of aged stellar populations. At the end, we concisely suggest how these topics can be tackled once the World Space Observatory enters into operation in the midst of this decade.Comment: 8 pages, 4 figures, accepted for publication in Astrophysics & Space Science, UV Universe special issu

The role of the synchrotron component in the mid infrared spectrum of M 87

We study in detail the mid-infrared Spitzer-IRS spectrum of M 87 in the range 5 to 20 micron. Thanks to the high sensitivity of our Spitzer-IRS spectra we can disentangle the stellar and nuclear components of this active galaxy. To this end we have properly subtracted from the M 87 spectrum, the contribution of the underlying stellar continuum, derived from passive Virgo galaxies in our sample. The residual is a clear power-law, without any additional thermal component, with a zero point consistent with that obtained by high spatial resolution, ground based observations. The residual is independent of the adopted passive template. This indicates that the 10 micron silicate emission shown in spectra of M 87 can be entirely accounted for by the underlying old stellar population, leaving little room for a possible torus contribution. The MIR power-law has a slope alpha ~ 0.77-0.82 (S$_\nu\propto\nu^{-\alpha}$), consistent with optically thin synchrotron emission.Comment: 5 pages, 4 figures, accepted for publication in ApJ main journa

Early Science with the Large Millimetre Telescope: Molecules in the Extreme Outflow of a proto-Planetary Nebula

Extremely high velocity emission likely related to jets is known to occur in some proto-Planetary Nebulae. However, the molecular complexity of this kinematic component is largely unknown. We observed the known extreme outflow from the proto-Planetary Nebula IRAS 16342-3814, a prototype water fountain, in the full frequency range from 73 to 111 GHz with the RSR receiver on the Large Millimetre Telescope. We detected the molecules SiO, HCN, SO, and $^{13}$CO. All molecular transitions, with the exception of the latter are detected for the first time in this source, and all present emission with velocities up to a few hundred km s$^{-1}$. IRAS 16342-3814 is therefore the only source of this kind presenting extreme outflow activity simultaneously in all these molecules, with SO and SiO emission showing the highest velocities found of these species in proto-Planetary Nebulae. To be confirmed is a tentative weak SO component with a FWHM $\sim$ 700 km s$^{-1}$. The extreme outflow gas consists of dense gas (n$_{\rm H_2} >$ 10$^{4.8}$--10$^{5.7}$ cm$^{-3}$), with a mass larger than $\sim$ 0.02--0.15 M$_{\odot}$. The relatively high abundances of SiO and SO may be an indication of an oxygen-rich extreme high velocity gas.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society Letter

Drying Kinetics of Oca (Oxalis Tuberosa)

One of the most important steps for agro-industrial industrialization is examining the kinetic behavior of products, to determine the ideal parameters to maintain their characteristics throughout the production chain. This study experimentally determined the drying kinetics of oca, an indigenous product of the Andean region, because there is no established information on the drying techniques of this tuber. The Andean region is the cradle of a large number of food crops that were domesticated and exploited by indigenous people thousands of years ago, even long before the expansion of the Inca civilization. In Ecuador, oca is perhaps the most important element of the daily diet, and an acceptable level of purity and hygiene has been reached. Oca provides fiber, essential amino acids and a low level of fat. In this study, a temperature of 60ºC was set at the beginning of each experimental run. The weight of the oca slices was measured every 10 min. The experiments were carried out in triplicate. Data were analyzed using StatGraphics software. Two drying periods were observed: the initial period of constant drying speed, where the removal of moisture corresponded to moisture not linked to the oca, while in the second stage, the internal moisture of the tuber was removed. Keywords: kinetic, drying, goose. RESUMEN Uno de los pasos más importantes para la industrialización agroindustrial es el comportamiento cinético de productos, esto en especial para conocer cuáles son los parámetros ideales para mantener las características sensoriales durante toda la cadena de producción. El presente documento determina experimentalmente la cinética de secado para un producto autóctono de la Región Andina, como lo es la oca, puesto que no existe información sobre las técnicas de secado de este tubérculo. En el Ecuador se ha alcanzado un aceptable nivel de pureza e higiene, la Oca es quizás el elemento más importante de la dieta diaria. La región andina es cuna de un gran número de cultivos alimenticios que fueron domesticados y aprovechados por pueblos autóctonos hace miles de años, inclusive mucho antes de la expansión de la civilización Inca. Aporta fibra, aminoácidos esenciales y un nivel bajo en grasa. La experimentación para conocer las curvas que modelan el comportamiento cinético del secado, se llevó a cabo por triplicado; luego de realizar la recolección de datos, estos fueron analizados utilizando el software estadístico StatGraphics. donde se obtuvo el respectivo análisis de varianza y las curvas. En el estudio se configuró una temperatura de 60ºC al inicio de cada corrida experimental, Se midió el peso de las rodajas de Oca cada 10 min, los datos fueron registrados y se procesó las tablas resultantes. En el estudio se pudo observar dos periodos de secado: Periodo inicial de velocidad de secado constante, donde la eliminación de humedad corresponde a la humedad no ligada a la oca, mientras en la segunda etapa se eliminó la humedad interna del tubérculo. Palabras claves: cinética, secado, oca

The LMT Galaxies' 3 mm Spectroscopic Survey: First Results

The molecular phase of the interstellar medium (ISM) in galaxies offers fundamental insight for understanding star-formation processes and how stellar feedback affects the nuclear activity of certain galaxies. We present here Large Millimeter Telescope spectra obtained with the Redshift Search Receiver, a spectrograph that cover simultaneously the 3 mm band from 74 to 111 GHz with a spectral resolution of around 100 km/s. The observed galaxies that have been detected previously in HCN, have different degrees of nuclear activity, one normal galaxy (NGC 6946), the starburst prototype (M 82) and two ultraluminous infrared galaxies (ULIRGs, IRAS 17208-0014 and Mrk 231). We plotted our data in the HCO+/HCN vs. HCN/13CO diagnostic diagram finding that NGC 6946 and M 82 are located close to other normal galaxies; and that both IRAS 17208-0014 and Mrk 231 are close to the position of the well known ULIRG Arp 220 reported by Snell et al. (2011). We found that in Mrk 231 -- a galaxy with a well known active galactic nucleus -- the HCO+/HCN ratio is similar to the ratio observed in other normal galaxies.Comment: Proceedings to appear in "Massive Young Star Clusters Near and Far: From the Milky Way to Reionization", 2013 Guillermo Haro Conference. Eds. Y. D. Mayya, D. Rosa-Gonzalez, & E. Terlevich, INAOE and AMC. 5 pages, 1 figur