5,284 research outputs found

    Impact of Farmland Preservation Programs on the Rate of Urban Development

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    Due to high losses of agricultural land in urbanizing areas over the past several years, state and local governments have adopted zoning regulations, right-to-farm ordinances, preferential property tax programs, and other means to protect agricultural land resources. Critics of the farmland preservation efforts note that these programs may only delay the ultimate conversion of farmland to urban uses and may simply shift urban development to neighboring areas (positive spillover effects). An alternative means of permanently protecting farmland is provided by purchase of development rights (PDR) programs, which enroll acreage from landowners who voluntarily sell the development rights to their farmland. Although ownership and all other property rights are retained by the owner, the option to develop the land for urban uses is removed from the current and all subsequent landowners. The purpose of this paper is to develop an empirical model of the impact of PDR programs on urban land development rates. To estimate the empirical model, we form a dependent variable based on county level rates of urban development from the USDA National Resources Inventory (NRI) data base for nine states in the Northeast US that have adopted farmland protection measures during the sample period (1982-1997). The set of explanatory variables include dummy variables for the existence of an active PDR program in the county and active PDR programs in adjacent counties plus measures of demographics, farm returns, population growth, income, and site-specific factors gathered from several sources (e.g., Census of Agriculture, Census of Population, and USDA). The model is estimated using the ordinary least squares technique. Two key policy-relevant hypotheses: (1) PDR programs did not reduce the rate of urban development and (2) PDR programs did not induce positive spillover effects on neighboring counties. The test results suggest that PDRs may have had important more significant impact in the earlier years and did not cause positive spillover effects.Land Economics/Use,

    Mechanical Unfolding of a Simple Model Protein Goes Beyond the Reach of One-Dimensional Descriptions

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    We study the mechanical unfolding of a simple model protein. The Langevin dynamics results are analyzed using Markov-model methods which allow to describe completely the configurational space of the system. Using transition path theory we also provide a quantitative description of the unfolding pathways followed by the system. Our study shows a complex dynamical scenario. In particular, we see that the usual one-dimensional picture: free-energy vs end-to-end distance representation, gives a misleading description of the process. Unfolding can occur following different pathways and configurations which seem to play a central role in one-dimensional pictures are not the intermediate states of the unfolding dynamics.Comment: 10 pages, 6 figure

    On in situ Determination of Earth Matter Density in Neutrino Factory

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    We point out that an accurate in situ determination of the earth matter density \rho is possible in neutrino factory by placing a detector at the magic baseline, L = \sqrt{2} \pi / G_{F} N_{e} where N_{e} denotes electron number density. The accuracy of matter density determination is excellent in a region of relatively large theta_{13} with fractional uncertainty \delta \rho / \rho of about 0.43%, 1.3%, and \lsim 3% at 1 sigma CL at sin^2 2theta_{13}=0.1, 10^{-2}, and 3 x 10^{-3}, respectively. At smaller theta_{13} the uncertainty depends upon the CP phase delta, but it remains small, 3%-7% in more than 3/4 of the entire region of delta at sin^2 2theta_{13} = 10^{-4}. The results would allow us to solve the problem of obscured CP violation due to the uncertainty of earth matter density in a wide range of theta_{13} and delta. It may provide a test for the geophysical model of the earth, or it may serve as a method for stringent test of the MSW theory of neutrino propagation in matter once an accurate geophysical estimation of the matter density is available.Comment: 21 pages, 4 figures, version to appear in PR

    Physics Potential of Very Intense Conventional Neutrino Beams

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    The physics potential of high intensity conventional beams is explored. We consider a low energy super beam which could be produced by a proposed new accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil scintillator detectors are studied as possible candidates for a neutrino oscillation experiment which could improve our current knowledge of the atmospheric parameters and measure or severely constrain the parameter connecting the atmospheric and solar realms. It is also shown that a very large water detector could eventually observe leptonic CP violation. The reach of such an experiment to the neutrino mixing parameters would lie in-between the next generation of neutrino experiments (MINOS, OPERA, etc) and a future neutrino factory.Comment: Talk given at the Venice Conference on Neutrino Telescopes, Venice, March, 200

    Quantum finite automata and linear context-free languages: a decidable problem

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    We consider the so-called measure once finite quantum automata model introduced by Moore and Crutchfield in 2000. We show that given a language recognized by such a device and a linear context-free language, it is recursively decidable whether or not they have a nonempty intersection. This extends a result of Blondel et al. which can be interpreted as solving the problem with the free monoid in place of the family of linear context-free languages. © 2013 Springer-Verlag

    Restriction on the energy and luminosity of e+e- storage rings due to beamstrahlung

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    The role of beamstrahlung in high-energy e+e- storage-ring colliders (SRCs) is examined. Particle loss due to the emission of single energetic beamstrahlung photons is shown to impose a fundamental limit on SRC luminosities at energies 2E_0 >~ 140 GeV for head-on collisions and 2E_0 >~ 40 GeV for crab-waist collisions. With beamstrahlung taken into account, we explore the viability of SRCs in the E_0=240-500 GeV range, which is of interest in the precision study of the Higgs boson. At 2E_0=240 GeV, SRCs are found to be competitive with linear colliders; however, at 2E_0=400-500 GeV, the attainable SRC luminosity would be a factor 15-25 smaller than desired.Comment: Latex, 5 pages. v2 differs only by minor changes is abstract and introduction, one reference is added. v3 corresponds to the paper published in PR

    Physics opportunities with future proton accelerators at CERN

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    We analyze the physics opportunities that would be made possible by upgrades of CERN's proton accelerator complex. These include the new physics possible with luminosity or energy upgrades of the LHC, options for a possible future neutrino complex at CERN, and opportunities in other physics including rare kaon decays, other fixed-target experiments, nuclear physics and antiproton physics, among other possibilities. We stress the importance of inputs from initial LHC running and planned neutrino experiments, and summarize the principal detector R&D issues.Comment: 39 page, word document, full resolution version available from http://cern.ch/pofpa/POFPA-arXive.pd

    The Identity Correspondence Problem and its Applications

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    In this paper we study several closely related fundamental problems for words and matrices. First, we introduce the Identity Correspondence Problem (ICP): whether a finite set of pairs of words (over a group alphabet) can generate an identity pair by a sequence of concatenations. We prove that ICP is undecidable by a reduction of Post's Correspondence Problem via several new encoding techniques. In the second part of the paper we use ICP to answer a long standing open problem concerning matrix semigroups: "Is it decidable for a finitely generated semigroup S of square integral matrices whether or not the identity matrix belongs to S?". We show that the problem is undecidable starting from dimension four even when the number of matrices in the generator is 48. From this fact, we can immediately derive that the fundamental problem of whether a finite set of matrices generates a group is also undecidable. We also answer several question for matrices over different number fields. Apart from the application to matrix problems, we believe that the Identity Correspondence Problem will also be useful in identifying new areas of undecidable problems in abstract algebra, computational questions in logic and combinatorics on words.Comment: We have made some proofs clearer and fixed an important typo from the published journal version of this article, see footnote 3 on page 1

    Energy versus information based estimations of dissipation using a pair of magnetic colloidal particles

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    Using the framework of stochastic thermodynamics, we present an experimental study of a doublet of magnetic colloidal particles which is manipulated by a time-dependent magnetic field. Due to hydrodynamic interactions, each bead experiences a state-dependent friction, which we characterize using a hydrodynamic model. In this work, we compare two estimates of the dissipation in this system: the first one is energy based since it relies on the measured interaction potential, while the second one is information based since it uses only the information content of the trajectories. While the latter only offers a lower bound of the former, we find it to be simple to implement and of general applicability to more complex systems.Comment: Main text: 5 pages, 4 figures. Supplementary material: 5 pages, 5 figure

    TLEP, first step in a long-term vision for HEP

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    The discovery of H(126) has renewed interest in circular e+e- colliders that can operate as Higgs factories, which benefit from three unique characteristics: i) high luminosity and reliability, ii) the availability of several interaction points, iii) superior beam energy accuracy. TLEP is an e+e- storage ring of 80-km circumference that can operate with very high luminosity from the Z peak (90 GeV) to the top quark pair threshold (350 GeV). It can achieve transverse beam polarization at the Z peak and WW threshold, giving it unparalleled accuracy on the beam energy. A preliminary study indicates that an 80 km tunnel could be constructed around CERN. Such a tunnel would allow a 100 TeV proton-proton collider to be established in the same ring (VHE-LHC), offering a long term vision.Comment: This is a contribution to the the Snowmass process 2013: Frontier Capabilitie
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