6,969 research outputs found
THE EFFECTS OF FARMLAND, FARMLAND PRESERVATION AND OTHER NEIGHBORHOOD AMENITIES ON PROXIMATE HOUSING VALUES: RESULTS OF A CONJOINT ANALYSIS OF HOUSING CHOICE
Using stated-preference data from a choice-based conjoint analysis instrument, we estimate willingness to pay for the presence of neighboring land that is dedicated to agricultural use (versus a developed land use) and for the preservation of surrounding farmland as permanent cropland. The data also elucidate how individuals balance the values associated with nearby agricultural land patterns with other key neighborhood characteristics such as neighborhood parks, housing density, commute times, school quality and neighborhood safety. The median respondent from a randomly chosen sample of Columbus, Ohio homeowners was willing to pay 277 annually to preserve the same amount of farmland as permanent cropland. We find provision of neighborhood parks within housing developments to be a strong substitute for farmland preservation.Land Economics/Use,
The mass content of the Sculptor dwarf spheroidal galaxy
We present a new determination of the mass content of the Sculptor dwarf
spheroidal galaxy, based on a novel approach which takes into account the two
distinct stellar populations present in this galaxy. This method helps to
partially break the well-known mass-anisotropy degeneracy present in the
modelling of pressure-supported stellar systems.Comment: 6 pages, 3 figures. To appear in the proceedings of IAU Symposium 254
"The Galaxy disk in a cosmological context", Copenhagen, June 200
Optimization of MLS receivers for multipath environments
A receiver is designed for aircraft (A/C), which, as a component of the proposed Microwave Landing System (MLS), is capable of optimal performance in the multipath environments found in air terminal areas. Topics discussed include: the angle-tracking problem of the MLS receiver; signal modeling; preliminary approaches to optimal design; suboptimal design; and simulation study
Carbon and nitrogen abundances of individual stars in the Sculptor dwarf spheroidal galaxy
We present [C/Fe] and [N/Fe] abundance ratios and CH({\lambda}4300) and
S({\lambda}3883) index measurements for 94 red giant branch (RGB) stars in the
Sculptor dwarf spheroidal galaxy from VLT/VIMOS MOS observations at a resolving
power R= 1150 at 4020 {\AA}. This is the first time that [N/Fe] abundances are
derived for a large number of stars in a dwarf spheroidal. We found a trend for
the [C/Fe] abundance to decrease with increasing luminosity on the RGB across
the whole metallicity range, a phenomenon observed in both field and globular
cluster giants, which can be interpreted in the framework of evolutionary
mixing of partially processed CNO material. Both our measurements of [C/Fe] and
[N/Fe] are in good agreement with the theoretical predictions for stars at
similar luminosity and metallicity. We detected a dispersion in the carbon
abundance at a given [Fe/H], which cannot be ascribed to measurement
uncertainties alone. We interpret this observational evidence as the result of
the contribution of different nucleosynthesis sources over time to a not
well-mixed interstellar medium. We report the discovery of two new
carbon-enhanced, metal-poor stars. These are likely the result of pollution
from material enriched by asymptotic giant branch stars, as indicated by our
estimates of [Ba/Fe]> +1. We also attempted a search for dissolved globular
clusters in the field of the galaxy by looking for the distinctive C-N pattern
of second population globular clusters stars in a previously detected, very
metal-poor, chemodynamical substructure. We do not detect chemical anomalies
among this group of stars. However, small number statistics and limited spatial
coverage do not allow us to exclude the hypotheses that this substructure forms
part of a tidally shredded globular cluster.Comment: 18 pages, 14 figures, 3 tables. Accepted to A&
Enhancing the Performance of the T-Peel Test for Thin and Flexible Adhered Laminates
Symmetrically bonded thin and flexible T-peel specimens, when tested on
vertical travel machines, can be subject to significant gravitational loading;
with the associated asymmetry and mixed-mode failure during peeling. This can
cause erroneously high experimental peel forces to be recorded which leads to
uncertainty in estimating interfacial fracture toughness and failure mode. To
overcome these issues, a mechanical test fixture has been designed for use with
vertical test machines, that supports the unpeeled portion of the test specimen
and suppresses parasitic loads due to gravity from affecting the peel test. The
mechanism, driven by the test machine cross-head, moves at one-half of the
velocity of the cross-head such that the unpeeled portion always lies in the
plane of the instantaneous center of motion. Several specimens such as bonded
polymeric films, laminates, and commercial tapes were tested with and without
the fixture, and the importance of the proposed T-peel procedure has been
demonstrated
Measurement of CHD on Titan at Submillimeter Wavelengths
We present the first radio/submillimeter detection of monodeuterated methane
(CHD) in Titan's atmosphere, using archival data from of the Atacama Large
Millimeter/submillimeter Array (ALMA). The and
transitions at 465.235 and 465.250 GHz ( mm) were measured at
significance levels of and , respectively. These two
lines were modeled using the Non-linear optimal Estimator for MultivariatE
spectral analySIS (NEMESIS) radiative transfer code to determine the
disk-averaged CHD volume mixing ratio = in Titan's
stratosphere (at altitudes km). By comparison with the CH vertical
abundance profile measured by Cassini-Huygens mass spectrometry, the resulting
value for D/H in CH is . This is consistent
with previous ground-based and in-situ measurements from the Cassini-Huygens
mission, though slightly lower than the average of the previous values.
Additional CHD observations at higher spatial resolution will be required
to determine a value truly comparable with the Cassini-Huygens CH
measurements, by measuring CHD with ALMA close to Titan's equator. In the
post-Cassini era, spatially resolved observations of CHD with ALMA will
enable the latitudinal distribution of methane to be determined, making this an
important molecule for further studies.Comment: 9 pages, 4 figure
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