82,790 research outputs found

    Comments on the measurement of power spectra of the interplanetary magnetic field

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    Examination of possible noise sources in the measurement of the power spectrum of fluctuations in the interplanetary magnetic field shows that most measurements by fluxgate magnetometers are limited by digitization noise whereas the search coil magnetometer is limited by instrument noise. The folding of power about the Nyquist frequency or aliasing can be a serious problem at times for many magnetometers, but it is not serious during typical solar wind conditions except near the Nyquist frequency. Waves in the solar wind associated with the presence of the earth's bow shock can contaminate the interplanetary spectrum in the vicinity of the earth. However, at times the spectrum in this region is the same as far from the earth. Doppler shifting caused by the convection of waves by the solar wind makes the interpretation of interplanetary spectra difficult

    Facilitating researcher use of flight simulators

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    Researchers conducting experiments with flight simulators encounter numerous obstacles in bringing their ideas to the simulator. Research into how these simulators could be used more efficiently is presented. The study involved: (1) analyzing the Advanced Concepts Simulator software architecture, (2) analyzing the interaction between the researchers and simulation programmers, and (3) proposing a documentation tool for the researchers

    An introduction to quantitative remote sensing

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    The quantitative approach to remote sensing is discussed along with the analysis of remote sensing data. Emphasis is placed on the application of pattern recognition in numerically oriented remote sensing systems. A common background and orientation for users of the LARS computer software system is provided

    Inventories and the Propagation of Sectoral Shocks

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    This paper studies the dynamic properties of an imperfectly competitive economy with inventory holdings. In particular, we focus on the serial correlation in aggregate output and employment produced by the holding of inventories in one sector of the economy and the co-movement between sectors of an economy over the cycle resulting from demand linkages. This model is then contrasted with a simple, competitive real business cycle model with inventories. We find that the predictions of these models with regards to the co-movement of employment may differ. Based on this, we present empirical evidence on the co-movement of employment over the business cycle which is consistent with the predictions of the model of imperfect competition with inventory holdings and demand linkages.

    Isotope separation using metallic vapor lasers

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    The isotope U235 is separated from a gasified isotope mixture of U235 and U238 by selectively exciting the former from the ground state utilizing resonant absorption of radiation from precisely tuned lasers. The excited isotope is then selectively ionized by electron bombardment. It then is separated from the remaining isotope mixture by electromagnetic separation

    Strategy for discovering a low-mass Higgs boson at the Fermilab Tevatron

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    We have studied the potential of the CDF and DZero experiments to discover a low-mass Standard Model Higgs boson, during Run II, via the processes ppˉp\bar{p} -> WH -> νbbˉ\ell\nu b\bar{b}, ppˉp\bar{p} -> ZH -> +bbˉ\ell^{+}\ell^{-}b\bar{b} and ppˉp\bar{p} -> ZH ->ννˉbbˉ\nu \bar{\nu} b\bar{b}. We show that a multivariate analysis using neural networks, that exploits all the information contained within a set of event variables, leads to a significant reduction, with respect to {\em any} equivalent conventional analysis, in the integrated luminosity required to find a Standard Model Higgs boson in the mass range 90 GeV/c**2 < M_H < 130 GeV/c**2. The luminosity reduction is sufficient to bring the discovery of the Higgs boson within reach of the Tevatron experiments, given the anticipated integrated luminosities of Run II, whose scope has recently been expanded.Comment: 26 pages, 8 figures, 7 tables, to appear in Physical Review D, Minor fixes and revision
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