23,742 research outputs found
Advanced Meteorological Temperature Sounder (AMTS) simulations
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
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 grid points and Reynolds
numbers of . 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 , 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
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
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
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
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
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
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
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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