6,672 research outputs found

    Diffractive Dijet Production and Nuclear Shadowing in pA Interactions

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    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

    Analysis of electrical transients created by lightning

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    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

    Unanticipated Money and Interest Rates

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    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.

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

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    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

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

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    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.

    NAIP/NLRC4 inflammasome activation in MRP8+ cells is sufficient to cause systemic inflammatory disease.

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    Inflammasomes are cytosolic multiprotein complexes that initiate protective immunity in response to infection, and can also drive auto-inflammatory diseases, but the cell types and signalling pathways that cause these diseases remain poorly understood. Inflammasomes are broadly expressed in haematopoietic and non-haematopoietic cells and can trigger numerous downstream responses including production of IL-1β, IL-18, eicosanoids and pyroptotic cell death. Here we show a mouse model with endogenous NLRC4 inflammasome activation in Lysozyme2 + cells (monocytes, macrophages and neutrophils) in vivo exhibits a severe systemic inflammatory disease, reminiscent of human patients that carry mutant auto-active NLRC4 alleles. Interestingly, specific NLRC4 activation in Mrp8 + cells (primarily neutrophil lineage) is sufficient to cause severe inflammatory disease. Disease is ameliorated on an Asc -/- background, and can be suppressed by injections of anti-IL-1 receptor antibody. Our results provide insight into the mechanisms by which NLRC4 inflammasome activation mediates auto-inflammatory disease in vivo
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