19,878 research outputs found

    Observed and theoretical variations of atmospheric ozone

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    Results are summarized from three areas of ozone research: (1) continued analysis of the global distribution of total ozone to extend the global ozone atlas to summarize 15 years (1957-72) of ground based observations; (2) analysis of balloon borne ozonesonde observations for Arosa, Switzerland, and Hohenpeissenberg, Germany (GFR); (3) contined processing of the (Orbiting Geophysical Observatory-4) satellite data to complete the analysis of the stratospheric ozone distribution from the available OGO-4 data. Results of the analysis of the total ozone observations indicated that the long term ozone variation have marked regional patterns and tend to alternate with season and hemisphere. It is becoming increasingly clear that these long period changes are associated with large scale variations in the general upper atmosphere circulation patterns

    Electrodynamics of superconductors

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    An alternate set of equations to describe the electrodynamics of superconductors at a macroscopic level is proposed. These equations resemble equations originally proposed by the London brothers but later discarded by them. Unlike the conventional London equations the alternate equations are relativistically covariant, and they can be understood as arising from the 'rigidity' of the superfluid wave function in a relativistically covariant microscopic theory. They predict that an internal 'spontaneous' electric field exists in superconductors, and that externally applied electric fields, both longitudinal and transverse, are screened over a London penetration length, as magnetic fields are. The associated longitudinal dielectric function predicts a much steeper plasmon dispersion relation than the conventional theory, and a blue shift of the minimum plasmon frequency for small samples. It is argued that the conventional London equations lead to difficulties that are removed in the present theory, and that the proposed equations do not contradict any known experimental facts. Experimental tests are discussed.Comment: Small changes following referee's and editor's comments; to be published in Phys.Rev.

    Wavelength Dependence of Solar Rotation and Solar Cycle UV Irradiance Variations

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    It is shown that for the 5-year period 1982 to 1987 the solar irradiance decrease is estimated to be about 5 to 7 percent over the spectral interval 195 to 225 nm. This change becomes progressively smaller with increasing wavelength. For the 2-1/3 year period, January 1987 to April 1989, the irradiance increases about 6 percent at 195 to 205 nm and about 2 percent between 215 to 250 nm. Both 27-day and 13.5-day relative amplitudes peak at the time near solar maximum (1982) but remain comparatively small between 1983 and the onset of solar cycle 22. An average 280 day oscillation is noted for wavelengths up to 230 nm. No physical mechanism is offered for this variation

    The Quasi-Biennial Oscillation in atmospheric ozone

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    Examination of the relationship between tropical stratosphere zonal wind and ozone indicate a variable response in latitude with Northern Hemisphere tropics and polar regions and Southern Hemisphere mid-latitudes showing the strongest response with relatively weaker response at Northern Hemisphere mid-latitudes and the Southern Hemisphere tropics. In tropical regions, the west winds and ozone maxima are in phase while at higher latitudes, a more nearly out-of-phase relationship prevails. At subtropical and middle latitudes, the QBO in ozone does not appear to change phases with altitude. These features are suggestive of an interaction between the tropical zonal winds and poleward transport of horizontal eddies in conjunction with the annual poleward transport of ozone

    New Physics Signals through CP Violation in B -> rho,pi

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    We describe here a method for detecting physics beyond the standard model via CP violation in B->rho,pi decays. Using a Dalitz-plot analysis to obtain alpha, along with an analytical extraction of the various tree (T) and penguin (P) amplitudes, we obtain a criterion for the absence of new physics (NP). This criterion involves the comparison of the measured |P/T| ratio with its value as predicted by QCD factorization. We show that the detection of NP via this method has a good efficiency when compared with the corresponding technique using B->pi,pi decays.Comment: 8 pages, 4 figures, talk given at MRST 2004: From Quarks to Cosmology, Concordia University, Montreal, May 200

    Precession during merger 1: Strong polarization changes are observationally accessible features of strong-field gravity during binary black hole merger

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    The short gravitational wave signal from the merger of compact binaries encodes a surprising amount of information about the strong-field dynamics of merger into frequencies accessible to ground-based interferometers. In this paper we describe a previously-unknown "precession" of the peak emission direction with time, both before and after the merger, about the total angular momentum direction. We demonstrate the gravitational wave polarization encodes the orientation of this direction to the line of sight. We argue the effects of polarization can be estimated nonparametrically, directly from the gravitational wave signal as seen along one line of sight, as a slowly-varying feature on top of a rapidly-varying carrier. After merger, our results can be interpreted as a coherent excitation of quasinormal modes of different angular orders, a superposition which naturally "precesses" and modulates the line-of-sight amplitude. Recent analytic calculations have arrived at a similar geometric interpretation. We suspect the line-of-sight polarization content will be a convenient observable with which to define new high-precision tests of general relativity using gravitational waves. Additionally, as the nonlinear merger process seeds the initial coherent perturbation, we speculate the amplitude of this effect provides a new probe of the strong-field dynamics during merger. To demonstrate the ubiquity of the effects we describe, we summarize the post-merger evolution of 104 generic precessing binary mergers. Finally, we provide estimates for the detectable impacts of precession on the waveforms from high-mass sources. These expressions may identify new precessing binary parameters whose waveforms are dissimilar from the existing sample.Comment: 11 figures; v2 includes response to referee suggestion

    Estimation of squeeze-film damping and inertial coefficients from experimental free-decay data

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    The results are given for an experimental program concerned with a parametric identification of the damping and inertial coefficients of a cylindrical squeeze-film bearing, through an analysis of transient response data. The results enable the operating range for which a linear model of the squeeze-film is appropriate to be determined. Comparisons are made between the estimated coefficients and theoretical predictions. Presentation is by courtesy of the Council of the Institution of Mechanical Engineers, London

    Predicted electric field near small superconducting ellipsoids

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    We predict the existence of large electric fields near the surface of superconducting bodies of ellipsoidal shape of dimensions comparable to the penetration depth. The electric field is quadrupolar in nature with significant corrections from higher order multipoles. Prolate (oblate) superconducting ellipsoids are predicted to exhibit fields consistent with negative (positive) quadrupole moments, reflecting the fundamental charge asymmetry of matter.Comment: To be published in Phys.Rev.Let
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