63,103 research outputs found

    Proposal for an Optical Test of the Einstein Equivalence Principle

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    The Einstein Equivalence Principle (EEP) underpins all metric theories of gravity. Its key element is the local position invariance of non-gravitational experiments, which entails the gravitational red-shift. Precision measurements of the gravitational red-shift tightly bound violations of the EEP only in the fermionic sector of the Standard Model, however recent developments of satellite optical technologies allow for its investigation in the electromagnetic sector. Proposals exploiting light interferometry traditionally suffer from the first-order Doppler effect, which dominates the weak gravitational signal necessary to test the EEP, making them unfeasible. Here, we propose a novel scheme to test the EEP, which is based on a double large-distance optical interferometric measurement. By manipulating the phase-shifts detected at two locations at different gravitational potentials it is possible to cancel-out the first-order Doppler effect and observe the gravitational red-shift implied by the EEP. We present the detailed analysis of the proposal within the post-Newtonian framework and the simulations of the expected signals obtained by using two realistic satellite orbits. Our proposal to overcome the first-order Doppler effect in optical EEP tests is feasible with current technology.Comment: manuscript improve

    Estimation and Analysis of Expenses of In-Lieu-Fee Projects that Mitigate Damage to Streams from Land Disturbance in North Carolina

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    As North Carolina’s economy has grown, the need to mitigate adverse impacts of land disturbance on aquatic ecosystems has also grown. When land disturbance adversely affects streams, a developer or the state’s Department of Transportation can satisfy mitigation requirements through payment of fees to the state’s Ecosystem Enhancement Program (EEP). EEP then manages a stream mitigation project on behalf of the responsible party. EEP has had regulatory authority to require stream mitigation for 10 years. The needs of EEP to reassess its mitigation fee and identify ways to reduce costs of the program have grown over the decade. The first objective of this study was to account for all EEP expenses of design-bid and design-bid-build projects. The second objective was to analyze the determinants of contractual expenses with a cost function. EEP has spent or committed to spend 46.34millionfor45design−buildordesignbid−buildprojectstorestoreorenhance191,374ft.ofstreams.Expensesperfoothavebeen46.34 million for 45 design-build or designbid-build projects to restore or enhance 191,374 ft. of streams. Expenses per foot have been 242.12. Given its mandate to cover expenses for stream mitigation, EEP must raise mitigation fees, especially those for urban projects, make changes to reduce project expenses, or do both. As the length of a restored or enhanced stream increases, the expenses per foot decrease. The decrease is more pronounced in undeveloped, rural areas. Thus, EEP could produce mitigation for less expense by financing fewer projects with longer reaches or by financing more projects in undeveloped, rural areas. Other states with in-lieu-fee programs for compensatory mitigation might also use these results to reduce contractual expenses.Environmental Economics and Policy,

    Core-log-seismic integration as a framework for determining the basin-wide significance of regional reflectors in the eastern equatorial Pacific

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    ODP Leg 138 in the eastern equatorial Pacific (EEP) provided a unique opportunity to understand the paleoceanographic significance of seismic reflectors in this climatically sensitive region. Carefully offset multiple cores were spliced into a complete stratigraphic section for the upper 250 m at each site and accurate, astronomically tuned time scales were generated from these composites. Well log data provided a means to correct composite depths to true depths as well as density and velocity data for the generation of synthetic seismograms. These synthetic seismograms were used to determine the paleoceanographic significance of regionally traceable reflectors by linking variations in the core record to the seismic record. The EEP reflectors are due to changes in carbonate content, primarily due to variations in surface productivity, as indicated by the presence of mats of the upwelling diatom Thalassiothrix longissima. The EEP composite GRAPE records were successfully used as a tuning target for GRAPE records in the central equatorial Pacific (CEP), as a means to detelxnine the basin-wide extent of EEP reflectors, and as a guide to the further interpretation of the CEP seismic record. It was found that EEP reflectors R3-t, R5, R6, R8-b, and Site 844 reflectors R 10, R 12-b and R 13, correspond to reflectors i n the CEP. However, some of the CEP reflectors, which were postulated to be due to periods of enhanced dissolution, also con\u27espond to diatom mats, and hence the origin of these reflectors must be reconsidered

    U.S. IMPORTS OF CANADIAN WHEAT: ESTIMATING THE EFFECT OF THE U.S. EXPORT ENHANCEMENT PROGRAM

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    It is hypothesized that the U.S. Export Enhancement Program (EEP) has had a role in increased U.S. imports of Canadian wheat. Using a set of world wheat models that differentiate wheat according to class and source, several conclusions concerning the role of EEP are reached. Over the period 1986-1993, EEP has been accountable for 40 to 48 percent of the yearly growth in U.S. imports of Canadian wheat. EEP subsidies in 1991/92 to China and Brazil caused significant diversion of Canadian wheat that would have been destined for those markets instead to the U.S. market. Further, it is argued that a quota on imports is not likely to have price-enhancing effects for U.S. wheat.Canada, export enhancement program, wheat, Agricultural and Food Policy, International Relations/Trade,

    The Equivalence Principle and g-2 Experiments

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    We consider the possibility of using measurements of anomalous magnetic moments of elementary particles as a possible test of the Einstein Equivalence Principle (EEP). For the class non-metric theories of gravity described by the \tmu formalism we find several novel mechanisms for breaking the EEP, and discuss the possibilities of setting new empirical constraints on such effects.Comment: 4 pages, latex, epsf, 1 figur
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