49,354 research outputs found

    On the field configuration in magnetic clouds

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    Interplanetary magnetic clouds are represented by cylindrically symmetric equilibrium solutions of the MHD equations. The radial magnetic pressure gradient of the force free field is balanced by the curvature stress. The field inside is essentially parallel to the cylinder axis, far outside it is oriented in azimuthal direction. These configurations therefore differ from the nonselfconsistent model where the field lines are tightly wound even near the axis

    The Case for an Orderly Resolution Regime for Systemically-Important Financial Institutions

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    Outlines the need to give the government authority to resolve a financial institution if its failure poses serious systemic risks, examines concerns and counterproposals, and offers recommendations and considerations for designing such a system

    Magnetohydrodynamic turbulence in the solar wind

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    Recent work in describing the solar wind as an MHD turbulent fluid has shown that the magnetic fluctuations are adequately described as time stationary and to some extent as spatially homogeneous. Spectra of the three rugged invariants of incompressible MHD are the principal quantities used to characterize the velocity and magnetic field fluctuations. Unresolved issues concerning the existence of actively developing turbulence are discussed

    Negotiate or Litigate? Effects of WTO Judicial Delegation on U.S. Trade Politics

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    Goldstein and Steinberg argue that the World Trade Organization Appellate Body has been able to use its authority to engage in judicial lawmaking to reduce trade barriers in ways that would not otherwise have been possible through negotiation. This lawmaking authority was not the result of a purposeful delegation; rather, it was an unintended byproduct of the creation of an underspecified set of rules and procedures. There is nevertheless a high rate of compliance with Appellate Body decisions because decentralized enforcement can induce domestic importers to lobby for trade liberalization. In the US, this judicial lawmaking may also allow the President to achieve trade policies that are more liberal than those desired by Congress, if compliance can be achieved by a regulatory change or by sole Executive action

    Reusable silica surface-insulation material

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    Material was specifically developed for manufacture of insulating tiles, but it can be molded into other shapes as required. Basic raw materials are high-purity silica fiber, fumed-silica powder, and reagent-grade starch. Only purest materials are used, and care must be taken to avoid contamination during processing

    Influence of Natural Inshore and Offshore Thermal Regimes on Egg Development and Time of Hatch in American lobsters, Homarus americanus

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    Some egg-bearing (ovigerous) American lobsters (Homarus americanus) make seasonal inshore-to-offshore movements, subjecting their eggs to different thermal regimes than those of eggs carried by lobsters that do not make these movements. Our goal was to determine if differences in thermal regimes influence the rate of egg development and the subsequent time of hatch. We subjected ovigerous lobsters to typical inshore or offshore water temperatures from September to August in the laboratory (n = 8 inshore and 8 offshore, each year) and in the field (n = 8 each, inshore and offshore), over 2 successive years. Although the rate of egg development did not differ significantly between treatments in the fall (P ∼ 0.570), eggs exposed to inshore thermal regimes developed faster in the spring (P \u3c 0.001). “Inshore” eggs hatched about 30 days earlier (mean = 26 June) than “offshore” eggs (mean = 27 July), and their time of development from the onset of eyespot to hatch was significantly shorter (inshore = 287 ± 11 days vs. offshore: 311.5 ± 7.5 days, P = 0.034). Associated growing degree-days (GDD) did not differ significantly between inshore and offshore thermal treatments (P = 0.061). However, eggs retained by lobsters exposed to offshore thermal regimes accumulated more GDD in the winter than did eggs carried by inshore lobsters, while eggs exposed to inshore temperatures acquired them more rapidly in the spring. Results suggest that seasonal movements of ovigerous lobsters influence the time and location of hatching, and thus the transport and recruitment of larvae to coastal and offshore locations

    Densities and abundances of hot cometary ions in the coma of P/Halley

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    On its flight by P/Halley, the Giotto spacecraft carried a High Energy Range Spectrometer (HERS) for measuring the properties of cometary ions picked up by the solar wind in the nearly collisionless regions of the coma. Preliminary estimates of the ion densities observed by HERS were reevaluated and extended; density profiles along the Giotto trajectory are presented for 13 values of ion mass/charge. Comparison with the physical-chemical model of the interaction of sunlight and the solar wind with the comet by other researchers reveals that, with the exception of protons and H2(+), all ion densities were at least an order of magnitude higher than predicted. The high ion densities cannot be explained on the basis of compression of the plasma, but require additional or stronger ionization mechanisms. Ratios of the densities of different ion species reveal an overabundance of carbonaceous material and an underabundance of H2(+) compared to the predictions of the Schmidt. While the densities of solar wind ions (H(+) and He(++)) changed sharply across a magnetic discontinuity located 1.35(10)(exp 5) km from the comet, this feature, which has been called both the 'cometopause' and the 'magnetic pileup boundary' was barely distinguishable in the density profiles of hot cometary ions. This result is consistent with the interpretation that the magnetic pileup boundary detected by Giotto was caused by a discontinuity in the solar wind and is not an intrinsic feature of the interaction of the solar wind with an active comet

    Sympathetic Wigner function tomography of a dark trapped ion

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    A protocol is provided to reconstruct the Wigner function for the motional state of a trapped ion via fluorescence detection on another ion in the same trap. This "sympathetic tomography" of a dark ion without optical transitions suitable for state measurements is based on the mapping of its motional state onto one of the collective modes of the ion pair. The quantum state of this vibrational eigenmode is subsequently measured through sideband excitation of the bright ion. Physical processes to implement the desired state transfer and read-out are derived, and the accomplishment of the scheme for different mass ratios is evaluated.Comment: 8 pages, 5 figure
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