18,809 research outputs found

    House prices and the proposed expansion of Chicago's O'Hare Airport

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    Quieter aircraft are causing the 65-db noise contour band around O'Hare Airport to shrink over time, even in the event that air traffic increases by nearly 60 percent after the proposed expansion of the airport. Forecasts imply that home prices will increase by nearly $280 million (in 1997 dollars) between 1997 and the time after the expansion of the airport as the number of homes subject to severe noise falls.Chicago (Ill.) ; Housing - Prices

    A Lack of Resolved Near-Infrared Polarization Across the Face of M51

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    The galaxy M51 was observed using the Mimir instrument on the Perkins telescope to constrain the resolved H-band (1.6 μ\mum) polarization across the galaxy. These observations place an upper limit of PH<0.05P_H<0.05% on the HH-band polarization across the face of M51, at 0.6 arcsecond pixel sampling. Even with smoothing to coarser angular resolutions, to reduce polarization uncertainty, the HH-band polarization remains undetected. The polarization upper limit at HH-band, when combined with previous resolved optical polarimetry, rules out a Serkowski-like polarization dependence on wavelength. Other polarization mechanisms cannot account for the observed polarization ratio (PH/PVRI≲0.05P_H/P{VRI} \lesssim 0.05) across the face of M51.Comment: 4 pages, 2 figures, Accepted for publication in ApJ

    Extended MSSM Neutralinos as the Source of the PAMELA Positron Excess

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    We consider a scenario within the Minimal Supersymmetric Standard Model extended by a singlet chiral superfield, in which neutralino dark matter annihilates to light singlet-like Higgs bosons, which proceed to decay to either electron-positron or muon-antimuon pairs. Unlike neutralino annihilations in the MSSM, this model can provide a good fit to the PAMELA cosmic ray positron fraction excess. Furthermore, the singlet-like scalar Higgs can induce a large Sommerfeld enhancement and provide an annihilation rate sufficient to accommodate the observed positron excess

    A Toy Model for Topology Change Transitions: Role of Curvature Corrections

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    We consider properties of near-critical solutions describing a test static axisymmetric D-dimensional brane interacting with a bulk N-dimensional black hole (N>D). We focus our attention on the effects connected with curvature corrections to the brane action. Namely, we demonstrate that the second order phase transition in such a system is modified and becomes first order. We discuss possible consequences of these results for merger transitions between caged black holes and black strings.Comment: 11 pages, 9 figures, v2: published versio

    Capturing Preference Heterogeneity in Stated Choice Models: A Random Parameter Logit Model of the Demand for GM Food

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    Analyses of data from random utility models of choice data have typically used fixed parameter representations, with consumer heterogeneity introduced by including factors such as the age, gender etc of the respondent. However, there is a class of models that assume that the underlying parameters of the estimated model (and hence preferences) are different for each individual within the sample, and that choices can be explained by identifying the parameters of the distribution from which they are drawn. Such a random parameter model is applied to stated choice data from the UK, and the results compared with standard fixed parameter models. The results provide new evidence of preferences for various aspects of the UK food system, particularly in relation to GM food but other environmental and technical aspects also. Indications of how random parameter models might be developed further are discussed on the basis of these results.random parameter logit, choice modelling, GMOs, food safety, Food Consumption/Nutrition/Food Safety,

    Transients of platoons with asymmetric and different Laplacians

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    We consider an asymmetric control of platoons of identical vehicles with nearest-neighbor interaction. Recent results show that if the vehicle uses different asymmetries for position and velocity errors, the platoon has a short transient and low overshoots. In this paper we investigate the properties of vehicles with friction. To achieve consensus, an integral part is added to the controller, making the vehicle a third-order system. We show that the parameters can be chosen so that the platoon behaves as a wave equation with different wave velocities. Simulations suggest that our system has a better performance than other nearest-neighbor scenarios. Moreover, an optimization-based procedure is used to find the controller properties
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