7,071 research outputs found

    Flux tubes and the type-I/type-II transition in a superconductor coupled to a superfluid

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    We analyze magnetic flux tubes at zero temperature in a superconductor that is coupled to a superfluid via both density and gradient (``entrainment'') interactions. The example we have in mind is high-density nuclear matter, which is a proton superconductor and a neutron superfluid, but our treatment is general and simple, modeling the interactions as a Ginzburg-Landau effective theory with four-fermion couplings, including only s-wave pairing. We numerically solve the field equations for flux tubes with an arbitrary number of flux quanta, and compare their energies. This allows us to map the type-I/type-II transition in the superconductor, which occurs at the conventional kappa = 1/sqrt(2) if the condensates are uncoupled. We find that a density coupling between the condensates raises the critical kappa and, for a sufficiently high neutron density, resolves the type-I/type-II transition line into an infinite number of bands corresponding to ``type-II(n)'' phases, in which n, the number of quanta in the favored flux tube, steps from 1 to infinity. For lower neutron density, the coupling creates spinodal regions around the type-I/type-II boundary, in which metastable flux configurations are possible. We find that a gradient coupling between the condensates lowers the critical kappa and creates spinodal regions. These exotic phenomena may not occur in nuclear matter, which is thought to be deep in the type-II region, but might be observed in condensed matter systems.Comment: 14 pages, improved discussion of the effects of varying the neutron/proton condensate ratio; added reference

    1998 PRICING PERFORMANCE OF MARKET ADVISORY SERVICES FOR CORN AND SOYBEANS

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    The purpose of this research report is to present an evaluation of advisory service pricing performance in 1998 for corn and soybeans. Specifically, the average price received by a subscriber to an advisory service is calculated for corn and soybean crops harvested in 1998. The average net advisory price across all 23 corn programs is 2.17perbushelsevencentsbelowthemarketbenchmarkprice.Thenetadvisorypricesforcornrangefromaminimumof2.17 per bushel - seven cents below the market benchmark price. The net advisory prices for corn range from a minimum of 1.93 per bushel to a maximum of 2.51perbushel.Theaveragenetadvisorypriceacrossall22soybeanprogramsis2.51 per bushel. The average net advisory price across all 22 soybean programs is 5.82 per bushel - four cents less than the market benchmark. The net advisory prices for soybeans range from a minimum of 5.11perbusheltoamaximumof5.11 per bushel to a maximum of 6.58 per bushel.Marketing,

    DO AGRICULTURAL MARKET ADVISORY SERVICES BEAT THE MARKET? EVIDENCE FROM THE WHEAT MARKET OVER 1995-1998

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    The purpose of this report is to address two basic performance questions for market advisory services in wheat: 1) Do market advisory services, on average, outperform an appropriate market benchmark? and 2) Do market advisory services exhibit persistence in their performance from year-to-year? Data on wheat net price received for advisory services, as reported by the AgMAS Project, are available for the 1995, 1996, 1997 and 1998 crop years. Not only do market advisory programs in wheat consistently fail to "beat the market," their performance is significantly worse than the market. On average, market advisory service performance is about $14 per acre below benchmark revenue, an economically non-trivial amount by any reasonable standard. The predictability results provide little evidence that future advisory service pricing performance can be predicted from past performance.Marketing,

    Results and recommendations from an intercomparison of six Hygroscopicity-TDMA systems

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    The performance of six custom-built Hygrocopicity-Tandem Differential Mobility Analyser (H-TDMA) systems was investigated in the frame of an international calibration and intercomparison workshop held in Leipzig, February 2006. The goal of the workshop was to harmonise H-TDMA measurements and develop recommendations for atmospheric measurements and their data evaluation. The H-TDMA systems were compared in terms of the sizing of dry particles, relative humidity (RH) uncertainty, and consistency in determination of number fractions of different hygroscopic particle groups. The experiments were performed in an air-conditioned laboratory using ammonium sulphate particles or an external mixture of ammonium sulphate and soot particles. The sizing of dry particles of the six H-TDMA systems was within 0.2 to 4.2% of the selected particle diameter depending on investigated size and individual system. Measurements of ammonium sulphate aerosol found deviations equivalent to 4.5% RH from the set point of 90% RH compared to results from previous experiments in the literature. Evaluation of the number fraction of particles within the clearly separated growth factor modes of a laboratory generated externally mixed aerosol was done. The data from the H-TDMAs was analysed with a single fitting routine to investigate differences caused by the different data evaluation procedures used for each H-TDMA. The differences between the H-TDMAs were reduced from +12/-13% to +8/-6% when the same analysis routine was applied. We conclude that a common data evaluation procedure to determine number fractions of externally mixed aerosols will improve the comparability of H-TDMA measurements. It is recommended to ensure proper calibration of all flow, temperature and RH sensors in the systems. It is most important to thermally insulate the aerosol humidification unit and the second DMA and to monitor these temperatures to an accuracy of 0.2 degrees C. For the correct determination of external mixtures, it is necessary to take into account size-dependent losses due to diffusion in the plumbing between the DMAs and in the aerosol humidification unit.Peer reviewe

    THE 1995 THROUGH 1998 PRICING PERFORMANCE OF MARKET ADVISORY SERVICES FOR WHEAT

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    The purpose of this research report is to present an evaluation of advisory service pricing performance from 1995 through 1998 for wheat. The average net advisory price across all 24 wheat programs in 1995 is 3.79perbushel,3.79 per bushel, 0.18 above the market benchmark price. The range in 1995 is 3.01to3.01 to 4.71 per bushel. The average net advisory service price for 23 wheat programs in 1996 is 3.82perbushel,3.82 per bushel, 0.13 below the market benchmark. The range in 1996 is 2.74to2.74 to 4.94 per bushel. The average net advisory price for all 20 wheat programs in 1997 is 2.64perbushel,2.64 per bushel, 0.58 below the market benchmark. The range in 1997 is 1.34to1.34 to 3.90 per bushel. Finally, the average net advisory price across all 21 services in 1998 is 2.36perbushel,2.36 per bushel, 0.54 below the market benchmark. The range in 1998 is 1.34to1.34 to 3.33 per bushel.Marketing,

    Orthographic vs. morphological incomplete neutralization effects

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    This study, following up on work on Dutch by Warner, Jongman, Sereno, and Kemps (2004. Journal of Phonetics, 32, 251–276), investigates the influence of orthographic distinctions and underlying morphological distinctions on the small sub-phonemic durational differences that have been called incomplete neutralization. One part of the previous work indicated that an orthographic geminate/singleton distinction could cause speakers to produce an incomplete neutralization effect. However, one interpretation of the materials in that experiment is that they contain an underlying difference in the phoneme string at the level of concatenation of morphemes, rather than just an orthographic difference. Thus, the previous effect might simply be another example of incomplete neutralization of a phonemic distinction. The current experiment, also on Dutch, uses word pairs which have the same underlying morphological contrast, but do not differ in orthography. These new materials show no incomplete neutralization, and thus support the hypothesis that orthography, but not underlying morphological differences, can cause incomplete neutralization effects

    Contemplating Mindfulness at Work: An Integrative Review

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    Mindfulness research activity is surging within organizational science. Emerging evidence across multiple fields suggests that mindfulness is fundamentally connected to many aspects of workplace functioning, but this knowledge base has not been systematically integrated to date. This review coalesces the burgeoning body of mindfulness scholarship into a framework to guide mainstream management research investigating a broad range of constructs. The framework identifies how mindfulness influences attention, with downstream effects on functional domains of cognition, emotion, behavior, and physiology. Ultimately, these domains impact key workplace outcomes, including performance, relationships, and well-being. Consideration of the evidence on mindfulness at work stimulates important questions and challenges key assumptions within management science, generating an agenda for future research

    Matter effects in the D0-D0bar system

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    We discuss the impact of matter effects in the D0-D0bar system. We show that such effects could, in principle, be measured, but that they cannot be used to probe the mass difference x_D or the lifetime difference y_D. This occurs because the mixing effects and the matter effects decouple at short times. We also comment briefly on the B systems.Comment: 6 pages, RevTe
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