3,232 research outputs found
Non-Market Valuation of Open Space and Other Amenities Associated with Retention of Lands in Agricultural Use
The most productive farmland in southcentral Alaska is currently
under intense development pressure due to rapid population increases
and consequential increases in demand for suburban housing. This
study utilizes a contingent valuation iterative bidding game to estimate
the willingness of Matanuska-Susitna Borough residents to pay to
preserve open space and other historical/environmental amenities
associated with farming activities. Determinants of consumer behavior
are addressed as well as total benefits and costs of various posited
development scenarios. This information may be useful to
policymakers assessing actions designed to purchase development
rights from Matanuska-Susitna farmers
Preparation and properties of amorphous MgB/MgO superstructures: A new model disordered superconductor
In this paper we introduce a novel method for fabricating MgB/MgO
multilayers and demonstrate the potential for using them as a new model for
disordered superconductors. In this approach we control the annealing of the
MgB to yield an interesting new class of disordered (amorphous)
superconductors with relatively high transition temperatures. The multilayers
appear to exhibit quasi-two-dimensional superconductivity with controlled
anisotropy. We discuss the properties of the multilayers as the thickness of
the components of the bilayers vary.Comment: 7 pages, 8 figure
Dual giant gravitons in AdS Y (Sasaki-Einstein)
We consider BPS motion of dual giant gravitons on Ad where
represents a five-dimensional Sasaki-Einstein manifold. We find that the
phase space for the BPS dual giant gravitons is symplectically isomorphic to
the Calabi-Yau cone over , with the K\"{a}hler form identified with the
symplectic form. The quantization of the dual giants therefore coincides with
the K\"{a}hler quantization of the cone which leads to an explicit
correspondence between holomorphic wavefunctions of dual giants and
gauge-invariant operators of the boundary theory. We extend the discussion to
dual giants in where is a seven-dimensional
Sasaki-Einstein manifold; for special motions the phase space of the dual
giants is symplectically isomorphic to the eight-dimensional Calabi-Yau cone.Comment: 14 pages. (v2) typo's corrected; factors of AdS radius reinstated for
clarity; remarks about dual giant wavefunctions in T^{1,1} expanded and put
in a new subsectio
Measurement of the Parallax of PSR B0950+08 Using the VLBA
A new technique has been developed to remove the ionosphere's distorting
effects from low frequency VLBI data. By fitting dispersive and non-dispersive
components to the phases of multi-frequency data, the ionosphere can be
effectively removed from the data without the use of {\em a priori} calibration
information. This technique, along with the new gating capability of the VLBA
correlator, was used to perform accurate astrometry on pulsar B0950+08,
resulting in a much improved measurement of this pulsar's proper motion
( mas/yr, mas/yr)
and parallax ( mas). This puts the pulsar at a distance of
parsecs, about twice as far as previous estimates, but in good
agreement with models of the electron density in the local bubble.Comment: 5 pages, Latex with AASTEX. Accepted for publication in Ap
The effect of bedrest on various parameters of physiological function. part xii- the effect of bedrest on bone mass and calcium balance
Bed rest effect on various parameters of physiological functions - bone mass and calcium balanc
The two-echelon capacitated vehicle routing problem: models and math-based heuristics
Multiechelon distribution systems are quite common in supply-chain and logistics. They are used by public administrations in their transportation and traffic planning strategies, as well as by companies, to model own distribution systems. In the literature, most of the studies address issues relating to the movement of flows throughout the system from their origins to their final destinations. Another recent trend is to focus on the management of the vehicle fleets required to provide transportation among different echelons. The aim of this paper is twofold. First, it introduces the family of two-echelon vehicle routing problems (VRPs), a term that broadly covers such settings, where the delivery from one or more depots to customers is managed by routing and consolidating freight through intermediate depots. Second, it considers in detail the basic version of two-echelon VRPs, the two-echelon capacitated VRP, which is an extension of the classical VRP in which the delivery is compulsorily delivered through intermediate depots, named satellites. A mathematical model for two-echelon capacitated VRP, some valid inequalities, and two math-heuristics based on the model are presented. Computational results of up to 50 customers and four satellites show the effectiveness of the methods developed
Embedding Fractional Quantum Hall Solitons in M-theory Compactifications
We engineer U(1)^n Chern-Simons type theories describing fractional quantum
Hall solitons (QHS) in 1+2 dimensions from M-theory compactified on eight
dimensional hyper-K\"{a}hler manifolds as target space of N=4 sigma model.
Based on M-theory/Type IIA duality, the systems can be modeled by considering
D6-branes wrapping intersecting Hirzebruch surfaces F_0's arranged as ADE
Dynkin Diagrams and interacting with higher dimensional R-R gauge fields. In
the case of finite Dynkin quivers, we recover well known values of the filling
factor observed experimentally including Laughlin, Haldane and Jain series.Comment: Latex, 14 pages. Modified version, to appear in IJGMM
Radio Emission from the Exoplanetary System ε Eridani
As part of a wider search for radio emission from nearby systems known or suspected to contain extrasolar planets, ε Eridani was observed by the Jansky Very Large Array (VLA) in the 2–4 GHz and 4–8 GHz frequency bands. In addition, as part of a separate survey of thermal emission from solar-like stars, ε Eri was observed in the 8–12 GHz and the 12–18 GHz bands of the VLA. Quasi-steady continuum radio emission from ε Eri was detected in the three high-frequency bands at levels ranging from 67 to 83 μJy. No significant variability is seen in the quasi-steady emission. The emission in the 2–4 GHz emission, however, is shown to be the result of a circularly polarized (up to 50%) radio pulse or flare of a few minutes in duration that occurred at the beginning of the observation. We consider the astrometric position of the radio source in each frequency band relative to the expected position of the K2V star and the purported planet. The quasi-steady radio emission at frequencies ≥8 GHz is consistent with a stellar origin. The quality of the 4–8 GHz astrometry provides no meaningful constraint on the origin of the emission. The location of the 2–4 GHz radio pulse is >2.5σ from the star; however, based on the ephemeris of Benedict et al., it is not consistent with the expected location of the planet either. If the radio pulse has a planetary origin, then either the planetary ephemeris is incorrect or the emission originates from another planet
Electronic properties of buried hetero-interfaces of LaAlO3 on SrTiO3
We have made very thin films of LaAlO3 on TiO2 terminated SrTiO3 and have
measured the properties of the resulting interface in various ways. Transport
measurements show a maximum sheet carrier density of 1016 cm-2 and a mobility
around 104 cm2 V-1 s-1. In situ ultraviolet photoelectron spectroscopy (UPS)
indicates that for these samples a finite density of states exists at the Fermi
level. From the oxygen pressure dependence measured in both transport as well
as the UPS, we detail, as reported previously by us, that oxygen vacancies play
an important role in the creation of the charge carriers and that these
vacancies are introduced by the pulsed laser deposition process used to make
the heterointerfaces. Under the conditions studied the effect of LaAlO3 on the
carrier density is found to be minimal.Comment: 19 pages, 6 figure
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