15,570 research outputs found
Exotic Forest Insects and Residential Property Values
This paper presents a case study of the economic damages to homeowners in a northern New Jersey community due to an exotic forest insect--the hemlock woolly adelgid. Hedonic property value methods are used to estimate the effect of hemlock health on property values. A statistically significant relationship between hemlock health and residential property values is established. Moreover, there are some signs of spillover impacts from hemlock decline, as negative effects are realized on the parcels where the declining hemlock stands are located as well as on neighboring properties. These results give some indication of the benefits of potential control programs and strategies and also show support for community- or neighborhood-based programs in residential settings.invasive species, economic impacts, hedonic property values, general spatial model, Land Economics/Use,
Conservatism implications of shock test tailoring for multiple design environments
A method for analyzing shock conservation in test specifications that have been tailored to qualify a structure for multiple design environments is discussed. Shock test conservation is qualified for shock response spectra, shock intensity spectra and ranked peak acceleration data in terms of an Index of Conservation (IOC) and an Overtest Factor (OTF). The multi-environment conservation analysis addresses the issue of both absolute and average conservation. The method is demonstrated in a case where four laboratory tests have been specified to qualify a component which must survive seven different field environments. Final judgment of the tailored test specification is shown to require an understanding of the predominant failure modes of the test item
An Alternative Accurate Tracer of Molecular Clouds: The "-Factor"
We explore the utility of CI as an alternative high-fidelity gas mass tracer
for Galactic molecular clouds. We evaluate the X-factor for the 609
m carbon line, the analog of the CO X-factor, which is the ratio of the
H column density to the integrated CO(1-0) line intensity. We use
3D-PDR to post-process hydrodynamic simulations of turbulent, star-forming
clouds. We compare the emission of CI and CO for model clouds irradiated by 1
and 10 times the average background and demonstrate that CI is a comparable or
superior tracer of the molecular gas distribution for column densities up to cm. Our results hold for both reduced and full chemical
networks. For our fiducial Galactic cloud we derive an average of
cmKkms and of cmKkms.Comment: 5 pages, 4 figures, 1 table, accepted to MNRAS Letter
Phase and micromotion of Bose-Einstein condensates in a time-averaged ring trap
Rapidly scanning magnetic and optical dipole traps have been widely utilised
to form time-averaged potentials for ultracold quantum gas experiments. Here we
theoretically and experimentally characterise the dynamic properties of
Bose-Einstein condensates in ring-shaped potentials that are formed by scanning
an optical dipole beam in a circular trajectory. We find that unidirectional
scanning leads to a non-trivial phase profile of the condensate that can be
approximated analytically using the concept of phase imprinting. While the
phase profile is not accessible through in-trap imaging, time-of-flight
expansion manifests clear density signatures of an in-trap phase step in the
condensate, coincident with the instantaneous position of the scanning beam.
The phase step remains significant even when scanning the beam at frequencies
two orders of magnitude larger than the characteristic frequency of the trap.
We map out the phase and density properties of the condensate in the scanning
trap, both experimentally and using numerical simulations, and find excellent
agreement. Furthermore, we demonstrate that bidirectional scanning eliminated
the phase gradient, rendering the system more suitable for coherent matter wave
interferometry.Comment: 10 pages, 7 figure
MAESTRO, CASTRO, and SEDONA -- Petascale Codes for Astrophysical Applications
Performing high-resolution, high-fidelity, three-dimensional simulations of
Type Ia supernovae (SNe Ia) requires not only algorithms that accurately
represent the correct physics, but also codes that effectively harness the
resources of the most powerful supercomputers. We are developing a suite of
codes that provide the capability to perform end-to-end simulations of SNe Ia,
from the early convective phase leading up to ignition to the explosion phase
in which deflagration/detonation waves explode the star to the computation of
the light curves resulting from the explosion. In this paper we discuss these
codes with an emphasis on the techniques needed to scale them to petascale
architectures. We also demonstrate our ability to map data from a low Mach
number formulation to a compressible solver.Comment: submitted to the Proceedings of the SciDAC 2010 meetin
Lorentz transformations of open systems
We consider open dynamical systems, subject to external interventions by
agents that are not completely described by the theory (classical or quantal).
These interventions are localized in regions that are relatively spacelike.
Under these circumstances, no relativistic transformation law exists that
relates the descriptions of the physical system by observers in relative
motion. Still, physical laws are the same in all Lorentz frames.Comment: Final version submitted to J. Mod. Opt. (Proc. of Gdansk conference
Penobscot Valley Prudent Investment Linking Our Towns A Report on Education,Housing, and Capital Planning Opportunities
This report brings together three studies focusing on regional planning and public investment opportunities in the Greater Bangor area. These documents were completed as part of the Penobscot Valley Prudent Investments Linking Our Towns (PVPILOT) research project sponsored by the Eastern Maine Development Corporation and by the TCSP Pilot Program of the Federal Highway Administration. Our goal is to help advance the discussion of regional cooperative strategies in education, housing, and the provision of public services
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