5,365 research outputs found
Advanced optimal extraction for the Spitzer/IRS
We present new advances in the spectral extraction of point-like sources
adapted to the Infrared Spectrograph onboard the Spitzer Space Telescope. For
the first time, we created a super-sampled point spread function of the
low-resolution modules. We describe how to use the point spread function to
perform optimal extraction of a single source and of multiple sources within
the slit. We also examine the case of the optimal extraction of one or several
sources with a complex background. The new algorithms are gathered in a plugin
called Adopt which is part of the SMART data analysis software.Comment: Accepted for publication in PAS
Canonical Equivalence of a Generic 2D Dilaton Gravity Model and a Bosonic String Theory
We show that a canonical tranformation converts, up to a boundary term, a
generic 2d dilaton gravity model into a bosonic string theory with a
Minkowskian target space.Comment: LaTeX file, 9 pages, no figure
PAH Strength and the Interstellar Radiation Field around the Massive Young Cluster NGC3603
We present spatial distribution of polycyclic aromatic hydrocarbons and
ionized gas within the Galactic giant HII region NGC3603. Using the IRS
instrument on board the Spitzer Space Telescope, we study in particular the PAH
emission features at ~5.7, 6.2, 7.7, 8.6, and 11.3um, and the [ArII] 6.99um,
[NeII] 12.81um, [ArIII] 8.99um, and [SIV] 10.51um forbidden emission lines. The
observations probe both ionized regions and photodissociation regions. Silicate
emission is detected close to the central cluster while silicate absorption is
seen further away. We find no significant variation of the PAH ionization
fraction across the whole region. The emission of very small grains lies closer
to the central stellar cluster than emission of PAHs. The PAH/VSG ratio
anticorrelates with the hardness of the interstellar radiation field suggesting
a destruction mechanism of the molecules within the ionized gas, as shown for
low-metallicity galaxies by Madden et al. (2006).Comment: Accepted for publication in ApJ. Corrected typo
Second Best Energy Policies
The paper considers the problem of resource allocation when factor groups attempt to obtain a share of real income which is greater than what would be imputed by classical economies. A formulation stressing the Divvy nature of the problem is given both in theoretical terms and with a framework which is susceptible to empirical estimation. Policy questions resulting from the formation of OPEC are discussed and a framework for policy analysis is given
A General Equilibrium Framework for the Divvy Economy
In a recent paper, G. Dantzig has formulated a model for resource allocation in the so called "Divvy Institutional Economy." The author proves the existence of a general equilibrium solution to the economic problem (in terms of prices and quantities of input factors and final goods) which at the same time satisfies agreed upon shares of monetary flows allocated to input resource groups and to output consumer groups. The agreement upon the share values is carried out by a political process, while the market mechanisms adjust the prices of primary resource inputs and the relative sizes of the consumer groups until those shares are satisfied. The inputs and outputs and the production and transformation technology are presented in an Input-Output format.
The formalization of the resource allocation problem takes into account the presence of institutionalized forces together with the market mechanism. Examples can be taken from empirical observation (collective bargaining, Congressional Budget Approval, indexed prices of raw material) is per se a major innovation with respect to more classical results. In the following sections we we will try to view the Divvy results in relation to the classic economic formulation of the problem and study possible implications of it
Elemental Abundances of Blue Compact Dwarfs from mid-IR Spectroscopy with Spitzer
We present a study of elemental abundances in a sample of thirteen Blue
Compact Dwarf (BCD) galaxies, using the 10--37m high resolution
spectra obtained with Spitzer/IRS. We derive the abundances of neon and sulfur
for our sample using the infrared fine-structure lines probing regions which
may be obscured by dust in the optical and compare our results with similar
infrared studies of starburst galaxies from ISO. We find a good correlation
between the neon and sulfur abundances, though sulfur is under-abundant
relative to neon with respect to the solar value. A comparison of the elemental
abundances (neon, sulfur) measured from the infrared data with those derived
from the optical (neon, sulfur, oxygen) studies reveals a good overall
agreement for sulfur, while the infrared derived neon abundances are slightly
higher than the optical values. This indicates that either the metallicities of
dust enshrouded regions in BCDs are similar to the optically accessible
regions, or that if they are different they do not contribute substantially to
the total infrared emission of the host galaxy.Comment: 11 pages, 6 figures, accepted by Ap
MS-ReRO and D-ROSE methods: Assessing relational uncertainty and evaluating scenarios risks and opportunities on multi-scale infrastructure systems
[EN] There is a growing interest in model-based decision support systems contributing to strategic planning. The application of these in the case of urban infrastructure planning requires methods specifically aimed at addressing the relational uncertainties arising from the complex, multi-scale, nature of this field. This study presents UPSS, a comprehensive urban planning support system integrating the generation of planning alternatives, the evaluation of alternatives under a set of relevant scenarios selected dynamically in a cognitive way, and the proposal of policies to accompany the planning alternative. For this purpose, UPSS integrates two novel methods. These deal respectively with the ex post identification of relevant scenarios for the evaluation of the vulnerability and resilience of the alternatives, and with the assessment of relational uncertainty. According to the risks and opportunities borne by the system, the process makes it possible to select an infrastructure plan to alleviate the problem of urban vulnerability, as well as a set of relational contracts for its proper implementation across the different governmental scales of the infrastructure system. The whole process is tested via a case study, in which USPP first proposes optimal urban infrastructure plans that contribute to ameliorate the problem of urban vulnerability in Spain, then evaluates the risks and opportunities attached to the planning alternatives, and finally presents sets of policy measures to accompany the implementation of the alternative selected.The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, along with FEDER funding (Project: BIA2017-85098-R).Salas, J.; Yepes, V. (2019). MS-ReRO and D-ROSE methods: Assessing relational uncertainty and evaluating scenarios risks and opportunities on multi-scale infrastructure systems. Journal of Cleaner Production. 216:607-623. https://doi.org/10.1016/j.jclepro.2018.12.083S60762321
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