8,537 research outputs found

    Table mountain observatory support to other programs

    Get PDF
    The Table Mountain Observatory (TMO) facilities include well equipped 24 inch and 16 inch telescopes with a 40 inch telescope (owned by Pomona College) due for completion during FY 89. This proposal is to provide operational support (equipment maintenance, setup, and observing assistnce) at TMO to other programs. The program currently most heavily supported by this grant is the asteroid photometry program directed by A. W. Harris. During 1987, about 20 asteroids were observed, including a near-earth asteroid, 1951 Midas. The photometric observations are used to derive rotation periods, estimate shapes and pole orientations, and to define the phase relations of asteroids. The E class asteroid 64 Angelina was observed, and showed the same opposition spike observed of 44 Jysa, last year. Comet observations are made with the narrow band camera system of David Rees, University College London. Observational support and training was provided to students and faculty from Claremont Colleges for variable star observing programs. Researchers propose to continue the asteroid program, with emphasis on measuring phase relations of low and high albedo asteroids at very low phase angles, and supporting collaborative studies of asteroid shapes

    Self-fulfillment Expectations, Speculation Attacks, and Capitol Controls

    Get PDF
    This paper examines the endogenous implementation of capital controls in the context of a fixed exchange rate regime. It is shown that if there exists a non-zero probability that the policymaker's response to a speculative attack on official foreign reserves will be the introduction of controls, such an attack may occur even when current and expected monetary policy is consistent with a permanently viable, control-free fixed exchange rate regime. Consequently, capital controls may be the outcome of self- fulfilling expectations rather than the result of imprudent economic policies.

    Near Earth asteroid orbit perturbation and fragmentation

    Get PDF
    Collisions by near earth asteroids or the nuclei of comets pose varying levels of threat to man. A relatively small object, approximately 100 meter diameter, which might be found on an impact trajectory with a populated region of the Earth, could potentially be diverted from an Earth impacting trajectory by mass driver rocket systems. For larger bodies, such systems would appear to be beyond current technology. For any size object, nuclear explosions appear to be more efficient, using either the prompt blow-off from neutron radiation, the impulse from ejecta of near-surface explosion for deflection, or as a fragmenting charge. Practical deflections of bodies with diameters of 0.1, 1, and 10 km require interception, years to decades prior to earth encounter, with explosions a few kilotons, megatons, or gigatons, respectively, of equivalent TNT energy to achieve orbital velocity changes or destruction to a level where fragments are dispersed to harmless spatial densities

    The 2060 Chiron: CCD photometry

    Get PDF
    R-band CCD photometry of 2060 was carried out on nine nights in Nov. and Dec. 1986. The rotation period is 5.9181 + or - 0.0003 hr and the peak to peak lightcurve amplitude is 0.088 + or - 0.0003 mag. Photometric parameters are H sub R = 6.24 + or - 0.02 mag and G sub R = + or - 0.15, though formal errors may not be realistic. The lightcurve has two pairs of extrema, but its asymmetry, as evidenced by the presence of significant odd Fourier harmonics, suggests macroscopic surface irregularities and/or the presence of some large scale albedo variegation. The observational rms residual is + or - 0.015 mag. On time scales from minutes to days there is no evidence for nonperiodic (cometary) brightness changes at the level of a few millimagnitudes

    Mapping Terrestrial Impact Craters with the TanDEM-X Digital Elevation Model

    Get PDF
    The TanDEM-X mission generates a global digital elevation model (DEM) with unprecedented properties. We use it for mapping confirmed terrestrial impact craters as listed in the Earth Impact Database. Both for simple and complex craters detailed investigations of the morphology of the particular structure and of the surrounding terrain can be performed

    Positive psychology and romantic scientism: Reply to comments on Brown, Sokal, & Friedman (2013)

    Full text link
    This is a response to five comments [American Psychologist 69, 626-629 and 632-635 (2014)] on our article arXiv:1307.7006.Comment: PDF, 9 page

    Goods Trade and International Equity Portfolios

    Get PDF
    We show that international trade in goods is the main determinant of international equity portfolios and offers a compelling -- theoretically and empirically -- resolution of the portfolio home bias puzzle. The model implies that investors can achieve full international risk diversification if the share of wealth invested in foreign equity matches their country's degree of openness (the imports to GDP share). The empirical evidence strongly supports this implication.

    The Roles of the Terms of Trade and Nontraded-Good-Prices in Exchange Rate Variations

    Get PDF
    This paper demonstrates that disturbances to supplies or demands for internationally traded goods affect exchange-rates differently than do disturbances in markets for nontraded goods. The paper develops a stochastic two-country equilibrium model of exchange rates, asset prices, and goods prices, with two internationally traded goods and a nontraded good in each country. Optimal portfolios differ across countries because of differences in consumption bundles. Changes in exchange-rates, asset prices, and goods prices occur in response to underlying disturbances to supplies and demands for goods. We examine the ways in which responses of the exchange-rate are related to parameters of tastes and production shares, and we discuss conditions under which these exchange-rate responses are "large" compared to the responses of ratios of nominal price indexes.

    Goods Trade and International Equity Portfolios

    Get PDF
    We show that international trade in goods is the main determinant of international equity portfolios and it also offers a compelling - theoretically and empirically - resolution of the portfolio home bias puzzle. The model implies that investors can achieve full international risk diversification if the share of wealth invested in foreign equity matches their country's degree of openness (the imports to GDP share). The empirical evidence strongly supports this implication.Portfolio home bias, imports, non-traded goods
    corecore