8,077 research outputs found

    Modeling the near-UV band of GK stars, Paper II: NLTE models

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    We present a grid of atmospheric models and synthetic spectral energy distributions (SEDs) for late-type dwarfs and giants of solar and 1/3 solar metallicity with many opacity sources computed in self-consistent Non-Local Thermodynamic Equilibrium (NLTE), and compare them to the LTE grid of Short & Hauschildt (2010) (Paper I). We describe, for the first time, how the NLTE treatment affects the thermal equilibrium of the atmospheric structure (T(tau) relation) and the SED as a finely sampled function of Teff, log g, and [A/H] among solar metallicity and mildly metal poor red giants. We compare the computed SEDs to the library of observed spectrophotometry described in Paper I across the entire visible band, and in the blue and red regions of the spectrum separately. We find that for the giants of both metallicities, the NLTE models yield best fit Teff values that are ~30 to 90 K lower than those provided by LTE models, while providing greater consistency between \log g values, and, for Arcturus, Teff values, fitted separately to the blue and red spectral regions. There is marginal evidence that NLTE models give more consistent best fit Teff values between the red and blue bands for earlier spectral classes among the solar metallicity GK giants than they do for the later classes, but no model fits the blue band spectrum well for any class. For the two dwarf spectral classes that we are able to study, the effect of NLTE on derived parameters is less significant.Comment: Submitted to The Astrophysical Journal. Observed spectrophotometric library, and grids of NLTE and LTE) synthetic spectra for GK stars available at http://www.ap.smu.ca/~ishort/PHOENI

    Analysis of multispectral images simulating ERTS observations

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    Simulation studies of selected aircraft and spacecraft acquired images were initiated in response to anticipated desires of the user community for simulated imagery prior to launch of ERTS-A. Principal modes of simulation included: (1) areas of coverage comparable to ERTS; (2) spatial resolutions within these images similar to ERTS; (3) spectral responses analogous to that expected from each channel on both the return beam vidicon and multispectral scanner, leading to production of photographic images that should appear similar to those representing each band in the two sensors; and (4) runthroughs of several analytical techniques, such as color density slicing, color additive viewing, and computer-generated reflectance and surface temperature maps, by which ERTS data can be analyzed, interpreted, and applied. The two areas involved in the simulation study were Wyoming and the Chesapeake Bay region

    ChromaStarPy: A stellar atmosphere and spectrum modeling and visualization lab in python

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    We announce ChromaStarPy, an integrated general stellar atmospheric modeling and spectrum synthesis code written entirely in python V. 3. ChromaStarPy is a direct port of the ChromaStarServer (CSServ) Java modeling code described in earlier papers in this series, and many of the associated JavaScript (JS) post-processing procedures have been ported and incorporated into CSPy so that students have access to ready-made "data products". A python integrated development environment (IDE) allows a student in a more advanced course to experiment with the code and to graphically visualize intermediate and final results, ad hoc, as they are running it. CSPy allows students and researchers to compare modeled to observed spectra in the same IDE in which they are processing observational data, while having complete control over the stellar parameters affecting the synthetic spectra. We also take the opportunity to describe improvements that have been made to the related codes, ChromaStar (CS), CSServ and ChromaStarDB (CSDB) that, where relevant, have also been incorporated into CSPy. The application may be found at the home page of the OpenStars project: http://www.ap.smu.ca/~ishort/OpenStars/ .Comment: See DOI zenodo.1095687. Accepted for publication in The Astrophysical Journa

    The correlated response in health cost accompanying selection for milk yield in Jerseys

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    Health data were recorded for 567 and 193 cows in selection and control herds, respectively. Health costs were expenses due to drugs, labor, and veterinary charges. Health expenses were grouped into one of six health functions: 1) mammary, 2) locomotion, 3) respiration, 4) reproduction, 5) digestion, and 6) other. Costs were summed across lactation and discounted to birth at rates of 0%, 3%, and 6%. Data were analyzed using a model that included year-season, parity, line, sire (line), and lactation length. Selection cows had significantly (P\u3c.001) higher health costs at all three discount rates. Differences were mainly due to higher (P\u3c.01) mammary costs. Differences between lines for other individual function costs were not significant, but were higher in selection cows. Parity, year-season, and stage of lactation were significant (P\u3c.001) non-genetic sources of variation in health costs. Costs were greater for third and later parities and during the first 30 days of lactation. Results indicate that health costs are likely to increase with selection for milk yield; however, additional revenues from increased yield would offset added costs. Increased management in early lactation and later parities may decrease health expense

    British attitudes to the Schlesftig-Holstein question, 1848-50

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    British attitudes during the Schleswig-Holstein War of 1848-50 were predominantly pro-Danish. The invasion of Denmark and the Elbe Duchies by the Confederation of German States, led by Prussia, was looked upon as an attempt by a large and aggressive power to bully a smaller and inoffensive neighbour into surrendering a large part of her territory and excellent ports on the Baltic and Korth Seas. Besides the belief that Denmark had a legal right to the Duchies it was feared that should Germany gain control of this strategic area, she would in time build a merchant fleet and a navy which could offer Britain serious competition. In addition, should the Germans have their own way, the Duchies would probably become members of the Zollverein which already imposed high tariffs on British Goods. Should the Duchies join this union, probably other north German areas would too, and perhaps even a good part of Scandinavia would be economically compelled to enter it. This danger helped to convince many Britons that the Helstat should remain intact

    H. Francis Short

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    Dr. H. Francis Short, Pitt State alum, was a member of the Kansas State Teachers College faculty from 1955 to 1986 (after it officially became Pittsburg State University). Short coached debate for 40 years and was known as the Head Gorilla on the national debate circuit during his years at PSU. Short served as PSU\u27s first KNEA president from 1974 to 1975

    Aspects of Heart Disease in Old Age with Special Reference to Hypertension

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