Analysis of electrical transients created by lightning

A series of flight tests was conducted using a specially-instrumented NASA Learjet to study the electrical transients created on an aircraft by nearby lightning. The instrumentation included provisions for the time-domain and frequency-domain recording of the electrical signals induced in sensors located both on the exterior and on the interior of the aircraft. The design and calibration of the sensors and associated measuring systems is described together with the results of the flight test measurements. The results indicate that the concept of providing instrumentation to follow the lightning signal from propagation field, to aircraft skin current, to current on interior wiring is basically sound. The results of the measurement indicate that the high frequency signals associated with lightning stroke precursor activity are important in generating electromagnetic noise on the interior of the aircraft. Indeed, the signals produced by the precursors are often of higher amplitude and of longer duration that the pulse produced by the main return stroke

Defusing inflammasomes.

In this issue of JEM, Boucher et al. (https://doi.org/10.1084/jem.20172222) report isolation of active caspase-1 from macrophages after inflammasome activation. Surprisingly, they find that caspase-1 is quickly inactivated upon autoproteolytic processing

Diffractive Dijet Production and Nuclear Shadowing in pA Interactions

We study the implications of non-universality observed recently in e p and pbar p diffraction for nuclear shadowing and diffractive dijet production in pA collisions.Comment: To appear in the proceedings of Quark Matter 2001, the 15th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, January 15-20, 2001, Stony Brook, N

The control of space manipulators subject to spacecraft attitude control saturation limits

The motions of robotic manipulators mounted on spacecraft can disturb the spacecraft's positions and attitude. These disturbances can surpass the ability of the system's attitude control reaction jets to control them, for the disturbances increase as manipulator speeds increase. If the manipulator moves too quickly the resulting disturbances can exceed the saturation levels of the reaction jets, causing excessive spacecraft motions. A method for planning space manipulator's motions is presented, so that tasks can be performed as quickly as possible without saturating the system's attitude control jets

Unanticipated Money and Interest Rates

Evidence on the relationship between unanticipated money and interestrates has been provided by two types of studies. First, several researchers have investigated the relationship using quarterly data. Second, a number of researchers have examined the effect of money announcement surprises on interest rates. In both instances, the correlation between money surprises and interest rates has usually been found to be non-negative.This paper first provides an interpretation of the correlation between unanticipated money and interest rates in terms of Federal Reserve policy objectives and operating procedures. Then, the correlation of unanticipated money and both short- and long-term interest rates is examined over weekly intervals, combining several aspects of the previous quarterly and announcement studies. In addition, the distinction between unpredicted and unperceived money also is considered.

Monetary Policy Regimes, Expected Inflation, and the Response of Interest Rates to Money Announcements

This paper examines the response of the term structure of interest rates to weekly money announcements. Estimated responses for both the pre- and post-October 1979 periods are first presented. Then, two competing hypotheses involving the policy anticipations and expected inflation effects are formally specified and compared to the estimated responses.Both hypotheses are found to be consistent with the responses, but they have sharply different implications about the Federal Reserve's short-run monetary policy. The expected inflation hypothesis implies that weekly money surprises should have persistent effects on the level of the money stock, reflecting shifts in the Federal Reserve's long-run target. In contrast, the policy anticipations hypothesis implies that the effectof money surprises should diminish over time, reflecting the Federal Reserve's desire to offset deviations from target. Additional empirical results reported in the paper support this latter description of the money stock process.