3,658 research outputs found

    An Analysis of the Selection of Arbitrators

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    This paper analyses data on union and employer rankings of different panels of arbitrators in an actual arbitration system. A random utility model of bargainer preferences is developed and estimated. The estimates indicate that unions and employers have similar preferences, in favor of lawyers, more experienced arbitrators, and arbitrators who seem to have previously favored their side. Alternative rankings models, which are estimated to test whether bargainers rank arbitrators strategically, reveal no evidence of strategic behavior.

    Negotiator Behavior Under Arbitration

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    The emerging empirical literature on the economics of arbitration has focused primarily on the behavior of arbitrators under alternative forms of arbitration. This article suggests that it is natural for empirical economists to now expand their focus to include issues related to the behavior of negotiators. In this connection, three key aspects of negotiator behavior are discussed: (1) the decision to settle a dispute voluntarily or to proceed to arbitration; (2) the strategy for selecting an arbitrator; and (3) the final bargaining position to advance before an arbitrator.

    Geodesics for Efficient Creation and Propagation of Order along Ising Spin Chains

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    Experiments in coherent nuclear and electron magnetic resonance, and optical spectroscopy correspond to control of quantum mechanical ensembles, guiding them from initial to final target states by unitary transformations. The control inputs (pulse sequences) that accomplish these unitary transformations should take as little time as possible so as to minimize the effects of relaxation and decoherence and to optimize the sensitivity of the experiments. Here we give efficient syntheses of various unitary transformations on Ising spin chains of arbitrary length. The efficient realization of the unitary transformations presented here is obtained by computing geodesics on a sphere under a special metric. We show that contrary to the conventional belief, it is possible to propagate a spin order along an Ising spin chain with coupling strength J (in units of Hz), significantly faster than 1/(2J) per step. The methods presented here are expected to be useful for immediate and future applications involving control of spin dynamics in coherent spectroscopy and quantum information processing

    The Measure of Success: Evaluating Corporate Citizenship Performance

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    This is the second publication resulting from the Measure of Success research project, designed to explore the current corporate perspective on and practices in measuring corporate citizenship performance. It presents a discussion of the evolution of corporate citizenship and how the political debates have influenced measurement practice; and a discussion of measurement as a management tool in the design and implementation of corporate citizenship programmes

    Production of a recombinant form of early pregnancy factor that can prolong allogeneic skin graft survival time in rats

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    Early pregnancy factor (EPF), an extracellular chaperonin 10 homologue, has immunosuppressive and growth factor properties. In order to carry out more extensive studies on the in vivo characteristics of EPF, a recombinant form of the molecule has been prepared. Recombinant human EPF (rEPF) was expressed in Escherichia coli using the plasmid pGEX-2T expression system. Potency of rEPF in vitro in the rosette inhibition test, the bioassay for EPF, was equivalent to that of native EPF (nEPF), purified from human platelets, and synthetic EPF (sEPF). However, the half-life of activity (50% decrease in the log value) in serum, following i.p. injection, was significantly decreased (3.2 h, compared with nEPF 6.2 days, sEPF 5.8 days). This was thought to be due to modification of the N-terminus of the recombinant molecule inhibiting binding to serum carrier proteins. Because EPF can modify Th1 responses, the ability of the recombinant molecule to suppress allogeneic graft rejection was investigated. Following skin grafts from Lewis rats to DA rats and vice versa, rEPF was delivered locally at the graft site and the effect on survival time of the allografts noted. Results demonstrated that rEPF treatment significantly prolonged skin graft survival time by as much as 55% in stringent models of transplantation across major histocompatibility barriers

    Electron wavepacket propagation and entanglement in a chain of coupled quantum dots

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    We study the coherent dynamics of one- and two-electron transport in a linear array of tunnel-coupled quantum dots. We find that this system exhibits a rich variety of coherent phenomena, ranging from electron wavepacket propagation and interference to two-particle bonding and entanglement. Our studies, apart from their relevance to the exploration of quantum dynamics and transport in periodic structures, are also aimed at possible applications in future quantum computation schemes.Comment: 10 pages, 8 figure

    Time Optimal Control in Spin Systems

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    In this paper, we study the design of pulse sequences for NMR spectroscopy as a problem of time optimal control of the unitary propagator. Radio frequency pulses are used in coherent spectroscopy to implement a unitary transfer of state. Pulse sequences that accomplish a desired transfer should be as short as possible in order to minimize the effects of relaxation and to optimize the sensitivity of the experiments. Here, we give an analytical characterization of such time optimal pulse sequences applicable to coherence transfer experiments in multiple-spin systems. We have adopted a general mathematical formulation, and present many of our results in this setting, mindful of the fact that new structures in optimal pulse design are constantly arising. Moreover, the general proofs are no more difficult than the specific problems of current interest. From a general control theory perspective, the problems we want to study have the following character. Suppose we are given a controllable right invariant system on a compact Lie group, what is the minimum time required to steer the system from some initial point to a specified final point? In NMR spectroscopy and quantum computing, this translates to, what is the minimum time required to produce a unitary propagator? We also give an analytical characterization of maximum achievable transfer in a given time for the two spin system.Comment: 20 Pages, 3 figure

    Structural analysis of the starfish SALMFamide neuropeptides S1 and S2: The N-terminal region of S2 facilitates self-association

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    The neuropeptides S1 (GFNSALMFamide) and S2 (SGPYSFNSGLTFamide), which share sequence similarity, were discovered in the starfish Asterias rubens and are prototypical members of the SALMFamide family of neuropeptides in echinoderms. SALMFamide neuropeptides act as muscle relaxants and both S1 and S2 cause relaxation of cardiac stomach and tube foot preparations in vitro but S2 is an order of magnitude more potent than S1. Here we investigated a structural basis for this difference in potency using spectroscopic techniques. Circular dichroism spectroscopy showed that S1 does not have a defined structure in aqueous solution and this was supported by 2D nuclear magnetic resonance experiments. In contrast, we found that S2 has a well-defined conformation in aqueous solution. However, the conformation of S2 was concentration dependent, with increasing concentration inducing a transition from an unstructured to a structured conformation. Interestingly, this property of S2 was not observed in an N-terminally truncated analogue of S2 (short S2 or SS2; SFNSGLTFamide). Collectively, the data obtained indicate that the N-terminal region of S2 facilitates peptide self-association at high concentrations, which may have relevance to the biosynthesis and/or bioactivity of S2 in vivo
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