9,611 research outputs found

    Fixing the Marriage Penalty Problem

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    Forecasting Methods for Marketing:* Review of Empirical Research

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    This paper reviews the empirical research on forecasting in marketing. In addition, it presents results from some small scale surveys. We offer a framework for discussing forecasts in the area of marketing, and then review the literature in light of that framework. Particular emphasis is given to a pragmatic interpretation of the literature and findings. Suggestions are made on what research is needed.forecasting, marketing, methods, review, research

    Cooperative Jahn-Teller Distortion in PrO2

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    We report neutron diffraction data on single crystal PrO2 which reveal a cooperative Jahn-Teller distortion at TD = 120 +/- 2 K. Below this temperature an internal distortion of the oxygen sublattice causes the unit cell of the crystallographic structure to become doubled along one crystal axis. We discuss several possible models for this structure. The antiferromagnetic structure below TN = 13.5 K is found to consist of two components, one of which shares the same doubled unit cell as the distorted crystallographic structure. We also present measurements of the magnetic susceptibility, the specific heat capacity and the electrical conductivity of PrO2. The susceptibility data show an anomaly at a temperature close to TD. From the specific heat capacity data we deduce that the ground state is doubly degenerate, consistent with a distortion of the cubic local symmetry. We discuss possible mechanisms for this. The conductivity shows an activated behaviour with an activation energy Ea = 0.262 +/- 0.003 eV.Comment: 12 pages, 14 figures, 2 tables. Additional suggested structure in v

    A Laser System for the Spectroscopy of Highly-Charged Bismuth Ions

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    We present and characterize a laser system for the spectroscopy on highly-charged ^209Bi^82+ ions at a wavelength of 243.87 nm. For absolute frequency stabilization, the laser system is locked to a near-infra-red laser stabilized to a rubidium transition line using a transfer cavity based locking scheme. Tuning of the output frequency with high precision is achieved via a tunable rf offset lock. A sample-and-hold technique gives an extended tuning range of several THz in the UV. This scheme is universally applicable to the stabilization of laser systems at wavelengths not directly accessible to atomic or molecular resonances. We determine the frequency accuracy of the laser system using Doppler-free absorption spectroscopy of Te_2 vapour at 488 nm. Scaled to the target wavelength of 244 nm, we achieve a frequency uncertainty of \sigma_{244nm} = 6.14 MHz (one standard deviation) over six days of operation.Comment: Contribution to the special issue on "Trapped Ions" in "Applied Physics B

    Quenched chirality in RbNiCl3_3

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    The critical behaviour of stacked-triangular antiferromagnets has been intensely studied since Kawamura predicted new universality classes for triangular and helical antiferromagnets. The new universality classes are linked to an additional discrete degree of freedom, chirality, which is not present on rectangular lattices, nor in ferromagnets. However, the theoretical as well as experimental situation is discussed controversially, and generic scaling without universality has been proposed as an alternative scenario. Here we present a careful investigation of the zero-field critical behaviour of RbNiCl3_3, a stacked-triangular Heisenberg antiferromagnet with very small Ising anisotropy. From linear birefringence experiments we determine the specific heat exponent α\alpha as well as the critical amplitude ratio A+/AA^+/A^-. Our high-resolution measurements point to a single second order phase transition with standard Heisenberg critical behaviour, contrary to all theoretical predictions. From a supplementary neutron diffraction study we can exclude a structural phase transition at TN_N. We discuss our results in the context of other available experimental results on RbNiCl3_3 and related compounds. We arrive at a simple intuitive explanation which may be relevant for other discrepancies observed in the critical behaviour of stacked-triangular antiferromagnets. In RbNiCl3_3 the ordering of the chirality is suppressed by strong spin fluctuations, yielding to a different phase diagram, as compared to e.g.\@ CsNiCl3_3, where the Ising anisotropy prevents these fluctuations

    Confinement of the Sun's interior magnetic field: some exact boundary-layer solutions

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    High-latitude laminar confinement of the Sun's interior magnetic field is shown to be possible, as originally proposed by Gough and McIntyre (1998) but contrary to a recent claim by Brun and Zahn (A&A 2006). Mean downwelling as weak as 2x10^-6cm/s -- gyroscopically pumped by turbulent stresses in the overlying convection zone and/or tachocline -- can hold the field in advective-diffusive balance within a confinement layer of thickness scale ~ 1.5Mm ~ 0.002 x (solar radius) while transmitting a retrograde torque to the Ferraro-constrained interior. The confinement layer sits at the base of the high-latitude tachocline, near the top of the radiative envelope and just above the `tachopause' marking the top of the helium settling layer. A family of exact, laminar, frictionless, axisymmetric confinement-layer solutions is obtained for uniform downwelling in the limit of strong rotation and stratification. A scale analysis shows that the flow is dynamically stable and the assumption of laminar flow realistic. The solution remains valid for downwelling values of the order of 10^-5cm/s but not much larger. This suggests that the confinement layer may be unable to accept a much larger mass throughput. Such a restriction would imply an upper limit on possible internal field strengths, perhaps of the order of hundreds of gauss, and would have implications also for ventilation and lithium burning. The solutions have interesting chirality properties not mentioned in the paper owing to space restrictions, but described at http://www.atmos-dynamics.damtp.cam.ac.uk/people/mem/papers/SQBO/solarfigure.htmlComment: 6 pages, 3 figures, to appear in conference proceedings: Unsolved Problems in Stellar Physic

    The Internationalisation of Pseudolaw: The Growth of Sovereign Citizen Arguments in Australia and Aotearoa New Zealand

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    Pseudolaw refers to the phenomenon whereby adherents adopt the forms and structures of legal argumentation while substituting the substantive content and underlying principles for a distinct and parallel set of beliefs. In this article, we explore and catalogue the forms of pseudolegal claims made by a particular subset of adherents – the sovereign citizen movement – in one part of the common law world: courts in Australia and Aotearoa New Zealand. Our study demonstrates both the internationalisation of pseudolaw, and that the phenomenon adapts and evolves to suit local legal discourses. We conclude by offering suggestions to respond to pseudolaw
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