1,826 research outputs found

    Growth, profits and technological choice: The case of the Lancashire cotton textile industry

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    Using Lancashire textile industry company case studies and financial records, mainly from the period just before the First World War, the processes of growth and decline are re-examined. These are considered by reference to the nature of Lancashire entrepreneurship and the impact on technological choice. Capital accumulation, associated wealth distributions and the character of Lancashire business organisation were sybiotically linked to the success of the industry before 1914. However, the legacy of that accumulation in later decades, chronic overcapacity, formed a barrier to reconstruction and enhanced the preciptious decline of a once great industry

    Ultraviolet Complete Quantum Gravity

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    An ultraviolet complete quantum gravity theory is formulated in which vertex functions in Feynman graphs are entire functions and the propagating graviton is described by a local, causal propagator. The cosmological constant problem is investigated in the context of the ultraviolet complete quantum gravity.Comment: 11 pages, no figures. Changes to text. Results remain the same. References added. To be published in European Physics Journal Plu

    A Golf Programme for People with Severe and Enduring Mental Health Problems

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    This article reports a pioneering golf programme for people with severe and enduring mental health problems. Following a discussion of the problems and possibilities of golf as a form of physical activity for this group, we outline the structure, organisation, and ethos of the golf programme. Through an analysis of qualitative case study data collected during the programme, we discuss the response to the programme from service users and mental health professionals. We conclude by highlighting aspects of the programme which were critical to its success and offering suggestions for further initiatives in this area

    Non-equilibrium stationary state of a two-temperature spin chain

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    A kinetic one-dimensional Ising model is coupled to two heat baths, such that spins at even (odd) lattice sites experience a temperature TeT_{e} (% T_{o}). Spin flips occur with Glauber-type rates generalised to the case of two temperatures. Driven by the temperature differential, the spin chain settles into a non-equilibrium steady state which corresponds to the stationary solution of a master equation. We construct a perturbation expansion of this master equation in terms of the temperature difference and compute explicitly the first two corrections to the equilibrium Boltzmann distribution. The key result is the emergence of additional spin operators in the steady state, increasing in spatial range and order of spin products. We comment on the violation of detailed balance and entropy production in the steady state.Comment: 11 pages, 1 figure, Revte

    Weather Forecasting for Weather Derivatives

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    We take a nonstructural time-series approach to modeling and forecasting daily average temperature in ten U.S. cities, and we inquire systematically as to whether it may prove useful from the vantage point of participants in the weather derivatives market. The answer is, perhaps surprisingly, yes. Time series modeling reveals both strong conditional mean dynamics and conditional variance dynamics in daily average temperature, and it reveals sharp differences between the distribution of temperature and the distribution of temperature surprises. Most importantly, it adapts readily to produce the long-horizon forecasts of relevance in weather derivatives contexts. We produce and evaluate both point and distributional forecasts of average temperature, with some success. We conclude that additional inquiry into nonstructural weather forecasting methods, as relevant for weather derivatives, will likely prove useful. Key Words: Risk management; hedging; insurance; seasonality; average temperature; financial derivatives; density forecasting JEL Codes: G0, C1 Acknowledgments: For financial support we thank the National Science Foundation, the Wharton Financial Institutions Center, and the Wharton Risk Management and Decision Process Center. For helpful comments we thank Marshall Blume, Larry Brown, Jeff Considine, John Dutton, Ren Garcia, Stephen Jewson, Vince Kaminski, Paul Kleindorfer, Howard Kunreuther, Yu Li, Bob Livezey, Cliff Mass, Don McIsaac, Nour Meddahi, David Pozo, Matt Pritsker, S.T. Rao, Claudio Riberio, Til Schuermann and Yihong Xia. We are also grateful for comments by participants at the American Meteorological Society's Policy Forum on Weather, Climate and Energy. None of those thanked, of course, are responsible in any way for the outcome. Address corresponde..

    Neutrino Mass from R-parity Violation in Split Supersymmetry

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    We investigate how the observed neutrino data can be accommodated by R-parity violation in Split Supersymmetry. The atmospheric neutrino mass and mixing are explained by the bilinear parameters ξi\xi_i inducing the neutrino-neutralino mixing as in the usual low-energy supersymmetry. Among various one-loop corrections, only the quark-squark exchanging diagrams involving the order-one trilinear couplings λi23,i32\lambda'_{i23,i32} can generate the solar neutrino mass and mixing if the scalar mass mSm_S is not larger than 10910^9 GeV. This scheme requires an unpleasant hierarchical structure of the couplings, e.g., λi23,i321\lambda_{i23,i32}\sim 1, λi33104\lambda'_{i33} \lesssim 10^{-4} and ξi106\xi_i \lesssim 10^{-6}. On the other hand, the model has a distinct collider signature of the lightest neutralino which can decay only to the final states, liW()l_i W^{(*)} and νZ()\nu Z^{(*)}, arising from the bilinear mixing. Thus, the measurement of the ratio; Γ(eW()):Γ(μW()):Γ(τW())\Gamma(e W^{(*)}) : \Gamma(\mu W^{(*)}) : \Gamma(\tau W^{(*)}) would provide a clean probe of the small reactor and large atmospheric neutrino mixing angles as far as the neutralino mass is larger than 62 GeV.Comment: 10 pages, 3 figures, version submitted to JHE

    Cathodoluminescence study of ZnO wafers cut from hydrothermal crystals

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    ZnO is a wide bandgap semiconductor with very promising expectation for UV optoelectronics. The existence of large crystals should allow homoepitaxial growth of ZnO films for advanced optoelectronic devices. However, the ZnO substrates are not yet mature. Both defect induced by growth and by polishing together with the high reactivity of the surface are problems to their industrial application. Cathodoluminescence (CL) was used to probe the quality of substrates from two different suppliers. The surface damage was studied by varying the penetration depth of the electron beam, allowing to observe significant differences between the two samples within a 0.5-mm-thick surface layer. CL spectra show a complex band (P1) at _3.3 eV composed of two overlapped bands (3.31 and 3.29 eV) related to point defects (PD) and the 1-LO phonon replica of the free exciton (FX-1LO). This band (P1) is shown to be very sensitive to the presence of defects and the surface and thermal treatments. Its intensity compared with the excitonic band intensity is demonstrated to provide criteria about the quality of the substrates

    Associative memory storing an extensive number of patterns based on a network of oscillators with distributed natural frequencies in the presence of external white noise

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    We study associative memory based on temporal coding in which successful retrieval is realized as an entrainment in a network of simple phase oscillators with distributed natural frequencies under the influence of white noise. The memory patterns are assumed to be given by uniformly distributed random numbers on [0,2π)[0,2\pi) so that the patterns encode the phase differences of the oscillators. To derive the macroscopic order parameter equations for the network with an extensive number of stored patterns, we introduce the effective transfer function by assuming the fixed-point equation of the form of the TAP equation, which describes the time-averaged output as a function of the effective time-averaged local field. Properties of the networks associated with synchronization phenomena for a discrete symmetric natural frequency distribution with three frequency components are studied based on the order parameter equations, and are shown to be in good agreement with the results of numerical simulations. Two types of retrieval states are found to occur with respect to the degree of synchronization, when the size of the width of the natural frequency distribution is changed.Comment: published in Phys. Rev.
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