10,707 research outputs found

    Inflation and the User Cost of Capital: Does Inflation Still Matter?

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    In the late 1970s, many economists argued that the deleterious effects of inflation on the user cost of capital for U.S. firms were large. Since that time, the tax code has changed, the level of inflation has dropped significantly, and the of investment has evolved considerably. In this paper, we demonstrate that the net effect of these changes has--under reasonable assumptions--not relegated inflation to the sidelines. Indeed, we conclude that: (1) inflation, even at its relatively low current rates, continues to increase the user cost of capital significantly; (2) the marginal gain in investment in response to a percentage-point reduction in inflation is larger for lower levels of inflation; (3) the beneficial effects for steady-state consumption of lowering inflation even further than has been achieved to date would likely be significant; and (4) inflation has only a small impact on intratemporal distortion in the allocation of capital within the domestic business sector. We also show that the magnitude of the inflation effect on the user cost of capital is likely much smaller in open economies.

    Noise reduction studies for the U-10 airplane

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    A study was undertaken by the NASA Langley Research Center to determine the noise reduction potential of the U-10 airplane in order to reduce its aural detection distance. Static and flyover noise measurements were made to document the basic airplane noise signature. Two modifications to the airplane configuration are suggested as having the best potential for substantially reducing aural detection distance with small penalty to airplane performance or stability and control. These modifications include changing the present 3-blade propeller to a 5-blade propeller, changing the propeller diameter, and changing the propeller gear ratio, along with the use of an engine exhaust muffler. The aural detection distance corresponding to normal cruising flight at an altitude of 1,000 ft over grassy terrain is reduced from 28,000 ft (5.3 miles) to about 50 percent of that value for modification 1, and to about 25 percent for modification 2. For the aircraft operating at an altitude of 300 ft, the analysis indicates that relatively straightforward modifications could reduce the aural detection distance to approximately 0.9 mile. Operation of the aircraft at greatly reduced engine speed (1650 rpm) with a 1.3-cu-ft muffler provides aural detection distances slightly lower than modification 1

    Slow-string limit and "antiferromagnetic" state in AdS/CFT

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    We discuss a slow-moving limit of a rigid circular equal-spin solution on R x S^3. We suggest that the solution with the winding number equal to the total spin approximates the quantum string state dual to the maximal-dimension ``antiferromagnetic'' state of the SU(2) spin chain on the gauge theory side. An expansion of the string action near this solution leads to a weakly coupled system of a sine-Gordon model and a free field. We show that a similar effective Hamiltonian appears in a certain continuum limit from the half-filled Hubbard model that was recently suggested to describe the all-order dilatation operator of the dual gauge theory in the SU(2) sector. We also discuss some other slow-string solutions with one spin component in AdS_5 and one in S^5.Comment: 32 pages, Latex v2: one footnote and references adde

    Tone-activated, remote, alert communication system

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    Pocket sized transmitter, frequency modulated by crystal derived tones, with integral loop antenna provides police with easy operating alert signal communicator which uses patrol car radio to relay signal. Communication channels are time shared by several patrol units

    An experimental study of the temporal statistics of radio signals scattered by rain

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    A fixed-beam bistatic CW experiment designed to measure the temporal statistics of the volume reflectivity produced by hydrometeors at several selected altitudes, scattering angles, and at two frequencies (3.6 and 7.8 GHz) is described. Surface rain gauge data, local meteorological data, surveillance S-band radar, and great-circle path propagation measurements were also made to describe the general weather and propagation conditions and to distinguish precipitation scatter signals from those caused by ducting and other nonhydrometeor scatter mechanisms. The data analysis procedures were designed to provide an assessment of a one-year sample of data with a time resolution of one minute. The cumulative distributions of the bistatic signals for all of the rainy minutes during this period are presented for the several path geometries

    Stability of Ferromagnetism in Hubbard models with degenerate single-particle ground states

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    A Hubbard model with a N_d-fold degenerate single-particle ground state has ferromagnetic ground states if the number of electrons is less or equal to N_d. It is shown rigorously that the local stability of ferromagnetism in such a model implies global stability: The model has only ferromagnetic ground states, if there are no single spin-flip ground states. If the number of electrons is equal to N_d, it is well known that the ferromagnetic ground state is unique if and only if the single-particle density matrix is irreducible. We present a simplified proof for this result.Comment: accepted for publication in J. Phys.
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