9,037 research outputs found

    The Giant Branches of Open and Globular Clusters in the Infrared as Metallicity Indicators: A Comparison with Theory

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    We apply the giant branch slope-[Fe/H] relation derived by Kuchinski et al. [AJ, 109, 1131 (1995)] to a sample of open clusters. We find that the slope of the giant branch in K vs. (J-K) color-magnitude diagrams correlates with [Fe/H] for open clusters as it does for metal-rich globular clusters but that the open cluster data are systematically shifted to less negative values of giant branch slope, at constant [Fe/H]. We use isochrone models to examine the theoretical basis for this relationship and find that for a given value of [Fe/H], the slope of the relationship remains constant with decreasing population age but the relation shifts to less negative values of giant branch slope with decreasing age. Both of these theoretical predictions agree with the trends found in the data. Finally, we derive new coefficients for the giant branch slope-[Fe/H] relation for specific members of 3 populations, metal-rich globular clusters, bulge stars and open clusters.Comment: 16 pages including 3 figures (AASTEX), AJ Accepted, also available at http://www.astronomy.ohio-state.edu/~martini/pubs.htm

    Computational Methods and Results for Structured Multiscale Models of Tumor Invasion

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    We present multiscale models of cancer tumor invasion with components at the molecular, cellular, and tissue levels. We provide biological justifications for the model components, present computational results from the model, and discuss the scientific-computing methodology used to solve the model equations. The models and methodology presented in this paper form the basis for developing and treating increasingly complex, mechanistic models of tumor invasion that will be more predictive and less phenomenological. Because many of the features of the cancer models, such as taxis, aging and growth, are seen in other biological systems, the models and methods discussed here also provide a template for handling a broader range of biological problems

    L'CO/LFIR Relations with CO Rotational Ladders of Galaxies Across the Herschel SPIRE Archive

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    We present a catalog of all CO (J=4-3 through J=13-12)), [CI], [NII] lines available from extragalactic spectra from the Herschel SPIRE Fourier Transform Spectrometer (FTS) archive combined with observations of the low-J CO lines from the literature and from the Arizona Radio Observatory. This work examines the relationships between LFIR, L'CO, and LCO/LCO(1-0). We also present a new method for estimating probability distribution functions (PDFs) from marginal signal-to-noise ratio Herschel} FTS spectra, which takes into account the instrumental "ringing" and the resulting highly correlated nature of the spectra. The slopes of log(LFIR) vs. log(L'CO) are linear for all mid- to high-J CO lines and slightly sublinear if restricted to (U)LIRGs. The mid- to high-J CO luminosity relative to CO J=1-0 increases with increasing LFIR, indicating higher excitement of the molecular gas, though these ratios do not exceed ~ 180. For a given bin in LFIR, the luminosities relative to CO J=1-0 remain relatively flat from J=6-5 through J=13-12, across three orders of magnitude of LFIR. A single component theoretical photon-dominated region (PDR) model cannot match these flat SLED shapes, though combinations of PDR models with mechanical heating added qualitatively match the shapes, indicating the need for further comprehensive modeling of the excitation processes of warm molecular gas in nearby galaxies.Comment: 17 pages, 4 figures (including appendix), accepted by ApJ. Full tables will be in VizieR upon publication, email first author for tables in the meantim

    The design and implementation of the Technical Facilities Controller (TFC) for the Goldstone deep space communications complex

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    The Technical Facilities Controller is a microprocessor-based energy management system that is to be implemented in the Deep Space Network facilities. This system is used in conjunction with facilities equipment at each of the complexes in the operation and maintenance of air-conditioning equipment, power generation equipment, power distribution equipment, and other primary facilities equipment. The implementation of the Technical Facilities Controller was completed at the Goldstone Deep Space Communications Complex and is now operational. The installation completed at the Goldstone Complex is described and the utilization of the Technical Facilities Controller is evaluated. The findings will be used in the decision to implement a similar system at the overseas complexes at Canberra, Australia, and Madrid, Spain

    Ocular attention-sensing interface system

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    The purpose of the research was to develop an innovative human-computer interface based on eye movement and voice control. By eliminating a manual interface (keyboard, joystick, etc.), OASIS provides a control mechanism that is natural, efficient, accurate, and low in workload

    Conservation of the Anegada Iguana (Cyclura pinguis)

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    The long-term survival of the Anegada Iguana (Cyclura pinguis) is uncertain. The species is in danger of becoming extinct due to habitat destruction, competition with feral livestock, and the introduction of non-native mammalian predators. In an effort to save the Anegada Iguana, the IUCN Iguana Specialist Group and the British Virgin Islands National Parks Trust began a concerted conservation effort in 1997. They initiated a headstart program in order to bolster the wild population until many of the problems facing the iguanas can be minimized or removed. Headstarted iguanas were released back into the wild in October of 2003 and 2004. This paper briefly reviews the natural history of C. pinguis and presents some preliminary results from the ongoing long-term monitoring of the subadult iguanas reintroduced to the wild

    Conservation of the Anegada Iguana (Cyclura pinguis)

    Get PDF
    The long-term survival of the Anegada Iguana (Cyclura pinguis) is uncertain. The species is in danger of becoming extinct due to habitat destruction, competition with feral livestock, and the introduction of non-native mammalian predators. In an effort to save the Anegada Iguana, the IUCN Iguana Specialist Group and the British Virgin Islands National Parks Trust began a concerted conservation effort in 1997. They initiated a headstart program in order to bolster the wild population until many of the problems facing the iguanas can be minimized or removed. Headstarted iguanas were released back into the wild in October of 2003 and 2004. This paper briefly reviews the natural history of C. pinguis and presents some preliminary results from the ongoing long-term monitoring of the subadult iguanas reintroduced to the wild
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