19,285 research outputs found
Federal Regulation and Aggregate Economic Growth
We introduce a new measure of the extent of federal regulation in the U.S. and use it to investigate the relationship between federal regulation and macroeconomic performance. We find that regulation has statistically and economically significant effects on aggregate output and the factors that produce it–total factor productivity (TFP), physical capital, and labor. Regulation has caused substantial reductions in the growth rates of both output and TFP and has had effects on the trends in capital and labor that vary over time in both sign and magnitude. Regulation also affects deviations about the trends in output and its factors of production, and the effects differ across dependent variables. Regulation changes the way output is produced by changing the mix of inputs. Changes in regulation and marginal tax rates offer a straightforward explanation for the productivity slowdown of the 1970s. Key Words: Regulation; macroeconomic performance; economic growth; productivity slowdown
An improved delayed self-heterodyne interferometer for linewidth measurements
The authors demonstrated a delayed self-heterodyne interferometer with a recirculating delay, in which loss was partially compensated by an erbium-doped fiber amplifier. A resolution limit of 606 Hz was achieved with an 11-km fiber delay line, as compared to 18.2 kHz for the standard single-pass case. The possible effect of spectral broadening due to amplifier noise is considered and found to have a negligible effect on the system performance
Frequency locking of an erbium-doped fiber ring laser to an external fiber Fabry-Perot resonator
An all-fiber, single-frequency, erbium-doped ring laser has been frequency locked to a resonance peak of an external fiber Fabry-Perot resonator by the Pound-Drever technique. In addition, feedback to the mode selection filter in the laser resonator eliminates occasional mode hopping completely, resulting in frequency-locked, stable, single-frequency operation of the laser for periods of several hours
Linewidth and frequency jitter measurement of an erbium-doped fiber ring laser by using a loss-compensated, delayed self-heterodyne interferometer
The single-mode line width of erbium-doped, single-frequency, fiber ring laser has been measured by using a newly developed loss-compensated delayed self-heterodyne interferometer that has a resolution of less than 600 Hz. The natural linewidth is determined to have an upper bound of less than 2 kHz. In addition, frequency jitter was found to be dominant over the natural linewidth, yielding an effective linewidth of approximately 4 kHz
Kinetics of the reduction of metalloproteins by chromous ion
The reduction of Cu(330) in Rhus vernicifera laccase by chromous ion is 30% faster than reduction of Cu(614) at room temperature [pH 4.8, µ = 0.1 (NaCl)], and two parallel first-order paths, attributed to heterogeneity of the protein, are observed at both wavelengths. The reactions of stellacyanin, spinach and French-bean plastocyanins, and cytochrome c with chromous ion under similar conditions are faster than that with laccase by factors of 102 to 104, and are first order in protein concentration. Comparison of rates and activation parameters for the reduction of "blue" copper in laccase, stellacyanin, and the two plastocyanins indicates that reduction of the Cu(614) site in laccase may occur by intramolecular electron transfer from one of the Cu(330) sites. Our value of ΔH (17.4 kcal/mol) for the chromous ion reduction of cytochrome c is consistent with a mechanism in which major conformational changes in the protein must accompany electron transfer
Reduction of the intensity noise from an erbium-doped fiber laser to the standard quantum limit by intracavity spectral filtering
The high frequency intensity noise of a tandem fiber Fabry–Perot erbium-doped fiber ring laser is reduced to the standard quantum limit, with a 0.5 dB experimental uncertainty. Noise reduction of >~14 dB is achieved by intracavity spectral filtering of weak side modes using a narrow-band fiber Fabry–Perot etalon
All fiber, low threshold, widely tunable single-frequency, erbium-doped fiber ring laser with a tandem fiber Fabry–Perot filter
An all fiber, widely tunable, single-frequency, erbium-doped fiber ring laser was constructed with a threshold pump power as low as 10 mW. Tuning over more than 30 nm was obtained by applying 0 to 17 dc V to an intracavity fiber Fabry–Perot filter. Threshold pump power versus wavelength data showed low variation over the tuning range. Mode hopping suppression with a tandem fiber Fabry–Perot filter is proposed and demonstrated. Stable single-frequency operation was demonstrated with side mode suppression higher than 35 dB
Measurements of the intensity noise of a broadly tunable, erbium-doped fiber ring laser, relative to the standard quantum limit
The intensity noise of an erbium-doped fiber ring laser is measured relative to the standard quantum limit. Over a tuning range of 24 nm, the noise power is within 20 dB of the shot noise floor and varies linearly with laser output power. Oscillations in the noise power spectrum are observed and attributed to beating of the lasing mode with other, strongly damped cavity modes
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