24,244 research outputs found

    Reflections on Persons in Petri Dishes

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    Why Water Markets Are Not Quick Fixes for Droughts in the Western United States

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    Water in the western United States can be bought and sold, but the transactions will always be complicated. Transfers of water will always be expensive and time consuming because of the hydrologic and institutional interconnections inherent to water. Our data show that most of the water rights in the West are messy. Therefore, markets cannot be quick fixes, and using markets for future water allocation, even if it is economically efficient, will take time and resources to set up. Untangling serial uses and negotiating multiple ownership claims are hurdles, not barriers, and they can be overcome in time but will require both time and money. Buying existing water rights may be less costly than building infrastructure to transport available water from long distances or desalinating seawater, but the transactions will come at a price. Municipalities may purchase water from farmers and thus bear the transaction costs directly, or the private sector may purchase agricultural water (e.g., Two Rivers Water and Farming, Colorado (Landry 2012)), bear the associated risk and transaction costs, and sell it on to municipalities. In either case, the end users will inevitably pay higher prices for water. Markets can and will be part of western U.S. water allocation, but they do not provide quick solutions. Droughts can focus public attention on the value of water and potentially increase the willingness-to-pay prices that reflect the transaction costs of tangled western water markets

    Quantum Uncertainty Considerations for Gravitational Lens Interferometry

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    The measurement of the gravitational lens delay time between light paths has relied, to date, on the source having sufficient variability to allow photometric variations from each path to be compared. However, the delay times of many gravitational lenses cannot be measured because the intrinsic source amplitude variations are too small to be detectable. At the fundamental quantum mechanical level, such photometric time stamps allow which-path knowledge, removing the ability to obtain an interference pattern. However, if the two paths can be made equal (zero time delay) then interference can occur. We describe an interferometric approach to measuring gravitational lens delay times using a quantum-eraser/restorer approach, whereby the time travel along the two paths may be rendered measurably equal. Energy and time being non-commuting observables, constraints on the photon energy in the energy-time uncertainty principle, via adjustments of the width of the radio bandpass, dictate the uncertainty of the time delay and therefore whether the path taken along one or the other gravitational lens geodesic is knowable. If one starts with interference, for example, which-path information returns when the bandpass is broadened (constraints on the energy are relaxed) to the point where the uncertainty principle allows a knowledge of the arrival time to better than the gravitational lens delay time itself, at which point the interference will disappear. We discuss the near-term feasibility of such measurements in light of current narrow-band radio detectors and known short time-delay gravitational lenses.Comment: 22 page

    Managing global expansion of media products and brands: A case study of FHM

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    By focusing on the case study of For Him Magazine (FHM)—a magazine that currently sells in 30 editions across 5 continents—this article explores the economics and main managerial challenges associated with global expansion of media products. The success of FHM demonstrates that, to calculate the full returns available from the brand image created by a magazine title, publishers will take into account not only opportunities for domestic and international exploitation of the magazine, but also the potential to extend the brand across additional media platforms and additional complementary product markets. This study focuses on how global expansion of FHM has been managed

    When is electromagnetic spectrum fungible?

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    Fungibility is a common assumption for market-based spectrum management. In this paper, we explore the dimensions of practical fungibility of frequency bands from the point of view of the spectrum buyer who intends to use it. The exploration shows that fungibility is a complex, multidimensional concept that cannot casually be assumed. We develop two ideas for quantifying fungibility-(i) of a fungibility space in which the 'distance' between two slices of spectrum provides score of fungibility and (ii) a probabilistic score of fungibility. © 2012 IEEE

    Discrete analogue computing with rotor-routers

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    Rotor-routing is a procedure for routing tokens through a network that can implement certain kinds of computation. These computations are inherently asynchronous (the order in which tokens are routed makes no difference) and distributed (information is spread throughout the system). It is also possible to efficiently check that a computation has been carried out correctly in less time than the computation itself required, provided one has a certificate that can itself be computed by the rotor-router network. Rotor-router networks can be viewed as both discrete analogues of continuous linear systems and deterministic analogues of stochastic processes.Comment: To appear in Chaos Special Focus Issue on Intrinsic and Designed Computatio

    New ways of being public: the experience of foundation degrees

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    This article explores the recent development of new spheres of public engagement within UK higher education through an analysis of the foundation degree qualification. These, according to the Higher Education Funding Council for England (HEFCE), were designed to equip students with the combination of technical skills, academic knowledge, and transferable skills increasingly being demanded by employers, and they have been identified as being at the forefront of educational agendas aimed at increasing employer engagement in the higher education (HE) sector. As such, they might be regarded as an expression of the 'increasing privatisation' of HE. However, this article argues that, on the contrary, they have enabled the development of new areas of public engagement relating to the design and delivery of courses as well as providing new opportunities for the pursuit of public policy goals such as widening participation. Such outcomes, it is argued, are the result of a number of factors that explain the 'publicness' of the qualification and that should be sustained to ensure the implementation of the 2006 Leitch Report in a manner that further develops public engagement

    The great war and Tommy Atkins

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    What Tommy Took to War tells sobering, fascinating stories that bring the ordinary British soldier's experiences back to life with poignant immediac

    Coherent-feedback quantum control with a dynamic compensator

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    I present an experimental realization of a coherent-feedback control system that was recently proposed for testing basic principles of linear quantum stochastic control theory [M. R. James, H. I. Nurdin and I. R. Petersen, to appear in IEEE Transactions on Automatic Control (2008), arXiv:quant-ph/0703150v2]. For a dynamical plant consisting of an optical ring-resonator, I demonstrate ~ 7 dB broadband disturbance rejection of injected laser signals via all-optical feedback with a tailored dynamic compensator. Comparison of the results with a transfer function model pinpoints critical parameters that determine the coherent-feedback control system's performance.Comment: 4 pages, 4 EPS figure
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