23,742 research outputs found

    Advanced Meteorological Temperature Sounder (AMTS) simulations

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    Simulation studies are reported on temperature retrievals from AMTS and their effect on atmospheric analysis. Observations are simulated from radiosonde reports and observed cloud cover. Temperature retrievals are performed and RMS temperature and thickness errors are calculated relative to the radiosonde profiles and compared to similarly generated HIRS statistics. Significant improvement over HIRS is found throughout the atmosphere but especially in the stratosphere and lower troposphere

    Large-scale anisotropy in stably stratified rotating flows

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    We present results from direct numerical simulations of the Boussinesq equations in the presence of rotation and/or stratification, both in the vertical direction. The runs are forced isotropically and randomly at small scales and have spatial resolutions of up to 102431024^3 grid points and Reynolds numbers of 1000\approx 1000. We first show that solutions with negative energy flux and inverse cascades develop in rotating turbulence, whether or not stratification is present. However, the purely stratified case is characterized instead by an early-time, highly anisotropic transfer to large scales with almost zero net isotropic energy flux. This is consistent with previous studies that observed the development of vertically sheared horizontal winds, although only at substantially later times. However, and unlike previous works, when sufficient scale separation is allowed between the forcing scale and the domain size, the total energy displays a perpendicular (horizontal) spectrum with power law behavior compatible with k5/3\sim k_\perp^{-5/3}, including in the absence of rotation. In this latter purely stratified case, such a spectrum is the result of a direct cascade of the energy contained in the large-scale horizontal wind, as is evidenced by a strong positive flux of energy in the parallel direction at all scales including the largest resolved scales

    Advanced cogeneration research study: Executive summary

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    This study provides a broad based overview of selected areas relevant to the development of a comprehensive Southern California Edison (SCE) advanced cogeneration project. The areas studied are: (1) Cogeneration potential in the SCE service territory; (2) Advanced cogeneration technologies; and (3) Existing cogeneration computer models. An estimated 3700 MW sub E could potentially be generated from existing industries in the Southern California Edison service territory using cogeneration technology. Of this total, current technology could provide 2600 MW sub E and advanced technology could provide 1100 MW sub E. The manufacturing sector (SIC Codes 20-39) was found to have the highest average potential for current cogeneration technology. The mining sector (SIC Codes 10-14) was found to have the highest potential for advanced technology

    Unravelling the Mysteries of the Leo Ring: An Absorption Line Study of an Unusual Gas Cloud

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    Since the 1980's discovery of the large (2x10^9 Msun) intergalactic cloud known as the Leo Ring, this object has been the center of a lively debate about its origin. Determining the origin of this object is still important as we develop a deeper understanding of the accretion and feedback processes that shape galaxy evolution. We present HST/COS observations of three sightlines near the Ring, two of which penetrate the high column density neutral hydrogen gas visible in 21 cm observations of the object. These observations provide the first direct measurement of the metallicity of the gas in the Ring, an important clue to its origins. Our best estimate of the metallicity of the ring is ~10% Zsun, higher than expected for primordial gas but lower than expected from an interaction. We discuss possible modifications to the interaction and primordial gas scenarios that would be consistent with this metallicity measurement.Comment: 11 pages, 7 figures, accepted Ap

    Discovery of a Metal-Line Absorber Associated with a Local Dwarf Starburst Galaxy

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    We present optical and near-infrared images, H I 21 cm emission maps, optical spectroscopy, and Hubble Space Telescope/Space Telescope Imaging Spectrograph ultraviolet spectroscopy of the QSO/galaxy pair SBS 1122+594/IC 691. The QSO sight line lies at a position angle of 27 degrees from the minor axis of the nearby dwarf starburst galaxy IC 691 (cz_gal = 1204+-3 km/s, L_B ~ 0.09 L*, current star formation rate = 0.08-0.24 solar masses per year) and 33 kpc (6.6 arcmin) from its nucleus. We find that IC 691 has an H I mass of M_HI = (3.6+-0.1) x 10^8 solar masses and a dynamical mass of M_dyn = (3.1+-0.5) x 10^10 solar masses. The UV spectrum of SBS 1122+594 shows a metal-line (Ly-alpha + C IV) absorber near the redshift of IC 691 at cz_abs = 1110+-30 km/s. Since IC 691 is a dwarf starburst and the SBS 1122+594 sight line lies in the expected location for an outflowing wind, we propose that the best model for producing this metal-line absorber is a starburst wind from IC 691. We place consistent metallicity limits on IC 691 ([Z/Zsun] ~ -0.7) and the metal-line absorber ([Z/Zsun] < -0.3). We also find that the galaxy's escape velocity at the absorber location is v_esc = 80+-10 km/s and derive a wind velocity of v_w = 160+-50 km/s. Thus, the evidence suggests that IC 691 produces an unbound starburst wind that escapes from its gravitational potential to transport metals and energy to the surrounding intergalactic medium.Comment: 31 pages, 8 figures; AJ in press; a version with high resolution figures can be downloaded from http://casa.colorado.edu/~keeney/research/papers/IC691.pd

    TASTE. III. A homogeneous study of transit time variations in WASP-3b

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    The TASTE project is searching for low-mass planets with the Transit Timing Variation (TTV) technique, by gathering high-precision, short-cadence light curves for a selected sample of transiting exoplanets. It has been claimed that the "hot Jupiter" WASP-3b could be perturbed by a second planet. Presenting eleven new light curves (secured at the IAC80 and UDEM telescopes) and re-analyzing thirty-eight archival light curves in a homogeneous way, we show that new data do not confirm the previously claimed TTV signal. However, we bring evidence that measurements are not consistent with a constant orbital period, though no significant periodicity can be detected. Additional dynamical modeling and follow-up observations are planned to constrain the properties of the perturber or to put upper limits to it. We provide a refined ephemeris for WASP-3b and improved orbital/physical parameters. A contact eclipsing binary, serendipitously discovered among field stars, is reported here for the first time.Comment: 10 pages, 6 figures, 4 tables; accepted for publication in A&

    The Arecibo Dual-Beam Survey: Arecibo and VLA Observations

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    The Arecibo Dual-Beam Survey is a "blind" 21 cm search for galaxies covering \~430 deg^2 of sky. We present the data from the detection survey as well as from the follow-up observations to confirm detections and improve positions and flux measurements. We find 265 galaxies, many of which are extremely low surface brightness. Some of these previously uncataloged galaxies lie within the zone of avoidance where they are obscured by the gas and dust in our Galaxy. 81 of these sources are not previously cataloged optically and there are 11 galaxies that have no associated optical counterpart or are only tentatively associated with faint wisps of nebulosity on the Digitized Sky Survey images. We discuss the properties of the survey and in particular we make direct determinations of the completeness and reliability of the sample. The behavior of the completeness and its dependencies is essential for determining the HI mass function. We leave the discussion of the mass function for a later paper, but do note that we find many low surface brightness galaxies and 7 sources with M_HI < 10^8 Msolar.Comment: 23 pages, 20 figures, accepted ApJS. For tables 2 and 3 only the first page has been included. ASCII tables are provided separatel

    Exotic Axions

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    We show that axion phenomenology may be significantly different than conventionally assumed in theories which exhibit late phase transitions (below the QCD scale). In such theories one can find multiple pseudoscalars with axion-like couplings to matter, including a string scale axion, whose decay constant far exceeds the conventional cosmological bound. Such theories have several dark matter candidates.Comment: 5 pages, 1 figure, References adde

    LGBQ-Specific Elderly Housing as a “Sparkling Sanctuary”: Boundary Work on LGBQ Identity and Community in Relationship to Potential LGBQSpecific Elderly Housing in Sweden

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    This study explored how boundaries in relationship to community and identity were created and negotiated among lesbian, gay, bisexual, and queer (LGBQ) people within the framework of picturing LGBQ-specific elderly housing as a housing alternative in older age, by applying focus group methodology. “An island as a sparkling sanctuary” was identified as a metaphor for how symbolic resources defining the LGBQ community can be manifested in LGBQ-specific qualities of elderly housing. The boundary work underlying this manifestation included elaborations on the dilemma between exclusiveness and normality. The findings illustrate further how symbolic resources and collective identities were developed through dialectic interplay between internal and external definitions. Further, the findings show how boundary work generated shared feelings of similarity and group membership. The associated symbolic and social resources not only served to deal with difficult situations but also to manifest LGBQ identity and sense of community as a “gold medal.
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