1,704 research outputs found

    EFFECTS OF AGRI-ENVIRONMENTAL PAYMENT POLICIES ON AGRICULTURAL TRADE

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    In many OECD countries, including the U.S., interest in developing agri-environmental payment programs is currently strong. In the future, the inclusion of an agri-environmental payment program into the WTO's "green box" could be more easily challenged by WTO member countries on the basis that it has more than "minimal" trade-distorting impacts on production. The goal of this paper is to conduct an ex ante analysis of the trade impacts of stylized examples of agri-environmental payment programs that have been proposed for implementation in the near future. To simulate the production and trade impacts of these programs, we use a partial equilibrium model of the U.S. agricultural sector in a sensitivity analysis across a range of design options for agri-environmental payments. For the three agri-environmental payment scenarios evaluated, the maximum change in exports ranges from a 7 percent decrease (wheat) to a 1 percent increase (soybeans). We do not expect the programs that decrease U.S. production, which would tend to have an upward pressure on world commodity prices, to be challenged before the WTO.Agricultural and Food Policy,

    Testing highly nonlinear fiber for squeezed-light generation

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    Squeezed light, which is easily degraded by loss, could benefit from generation directly in optical fiber. Furthermore, highly nonlinear fiber could offer more efficient generation with lower pump power and shorter fiber lengths than standard single-mode fiber. We investigate non-polarization-maintaining highly nonlinear fiber (HNLF) for squeezed-light generation by characterizing possible sources of excess noise, including its zero-dispersion wavelength (ZDW) variation and polarization noise. We find significant ZDW variation and excess polarization noise. We believe the polarization noise is from non-linear polarization-mode dispersion. These findings are indicative of excess noise that would reduce and potentially completely overtake any squeezing generated, except possibly using intensity difference detection.Comment: 7 pages, 5 figures, 1 tabl

    Entanglement-based quantum digital signatures over deployed campus network

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    The quantum digital signature protocol offers a replacement for most aspects of public-key digital signatures ubiquitous in today's digital world. A major advantage of a quantum digital signatures protocol is that it can have information-theoretic security, whereas public-key cryptography cannot. Here we demonstrate and characterize hardware to implement entanglement-based quantum digital signatures over our campus network. Over 25 hours, we collect measurements on our campus network, where we measure sufficiently low quantum bit error rates (<5\% in most cases) which in principle enable quantum digital signatures over up to 50 km as shown in rigorous simulation accompanied by a noise model developed specifically for our implementation. These results show quantum digital signatures can be successfully employed over deployed fiber. While the current implementation of our entanglement-based approach has a low signature rate, feasible upgrades would significantly increase the signature rate. In addition, our reported method provides great flexibility in the number of users.Comment: 16 pages, 5 figures, 1 tabl

    E-Type Delayed Fluorescence of a Phosphine-Supported Cu_2(μ-NAr_2)_2 Diamond Core: Harvesting Singlet and Triplet Excitons in OLEDs

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    A highly emissive bis(phosphine)diarylamido dinuclear copper(I) complex (quantum yield = 57%) was shown to exhibit E-type delayed fluorescence by variable temperature emission spectroscopy and photoluminescence decay measurement of doped vapor-deposited films. The lowest energy singlet and triplet excited states were assigned as charge transfer states on the basis of theoretical calculations and the small observed S_1−T_1 energy gap. Vapor-deposited OLEDs doped with the complex in the emissive layer gave a maximum external quantum efficiency of 16.1%, demonstrating that triplet excitons can be harvested very efficiently through the delayed fluorescence channel. The function of the emissive dopant in OLEDs was further probed by several physical methods, including electrically detected EPR, cyclic voltammetry, and photoluminescence in the presence of applied current

    Creating and Certifying the Professional Mediator -- Education and Credentialing

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    Existing and pending law school mediation programs, post-graduate mediator training programs, mentorship programs, credentialing movements, and continuing mediation education were examined by a panel and speakers directly involved in those fields. Are we effectively training new mediators in law schools and post-graduate programs? Should we, and how can we, credential mediators? Do good mediators need to be re-trained? How would continuing mediation educational requirements be implemented

    Creating and Certifying the Professional Mediator -- Education and Credentialing

    Get PDF
    Existing and pending law school mediation programs, post-graduate mediator training programs, mentorship programs, credentialing movements, and continuing mediation education were examined by a panel and speakers directly involved in those fields. Are we effectively training new mediators in law schools and post-graduate programs? Should we, and how can we, credential mediators? Do good mediators need to be re-trained? How would continuing mediation educational requirements be implemented

    Two-mode squeezing over deployed fiber coexisting with conventional communications

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    Squeezed light is a crucial resource for continuous-variable (CV) quantum information science. Distributed multi-mode squeezing is critical for enabling CV quantum networks and distributed quantum sensing. To date, multi-mode squeezing measured by homodyne detection has been limited to single-room experiments without coexisting classical signals, i.e., on ``dark'' fiber. Here, after distribution through separate fiber spools (5~km), 0.9±0.1-0.9\pm0.1-dB coexistent two-mode squeezing is measured. Moreover, after distribution through separate deployed campus fibers (about 250~m and 1.2~km), 0.5±0.1-0.5\pm0.1-dB coexistent two-mode squeezing is measured. Prior to distribution, the squeezed modes are each frequency multiplexed with several classical signals -- including the local oscillator and conventional network signals -- demonstrating that the squeezed modes do not need dedicated dark fiber. After distribution, joint two-mode squeezing is measured and recorded for post-processing using triggered homodyne detection in separate locations. This demonstration enables future applications in quantum networks and quantum sensing that rely on distributed multi-mode squeezing.Comment: 23 pages, 13 figures, 2 table

    Catalytic N_2-to-NH_3 Conversion by Fe at Lower Driving Force: A Proposed Role for Metallocene-Mediated PCET

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    We have recently reported on several Fe catalysts for N_2-to-NH_3 conversion that operate at low temperature (−78 °C) and atmospheric pressure while relying on a very strong reductant (KC_8) and acid ([H(OEt_2)_2][BArF_4]). Here we show that our original catalyst system, P_3^BFe, achieves both significantly improved efficiency for NH_3 formation (up to 72% for e^– delivery) and a comparatively high turnover number for a synthetic molecular Fe catalyst (84 equiv of NH_3 per Fe site), when employing a significantly weaker combination of reductant (Cp*_2Co) and acid ([Ph_2NH_2][OTf] or [PhNH_3][OTf]). Relative to the previously reported catalysis, freeze-quench Mössbauer spectroscopy under turnover conditions suggests a change in the rate of key elementary steps; formation of a previously characterized off-path borohydrido–hydrido resting state is also suppressed. Theoretical and experimental studies are presented that highlight the possibility of protonated metallocenes as discrete PCET reagents under the present (and related) catalytic conditions, offering a plausible rationale for the increased efficiency at reduced driving force of this Fe catalyst system
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