11,617 research outputs found

    A Panel Data Analysis of the Incidence and Impact of Over-education

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    This paper adds to the overeducation literature using panel data from the British Household Panel Survey. Much has been written about who is more likely to be overeducated, and the impact of being overeducated on wages, at particular points in time using cross-sectional data. Panel data allows us to control for unobserved individual heterogeneity in the determinants of incidence and impact of overeducation. The paper goes on to estimate the determinants of transitions out of overeducation, providing new information about its duration, and the factors that influence being in, and escaping from, this state

    H-alpha synoptic charts of solar activity during the first year of solar cycle 20, October 1964 - August 1965

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    Solar activity during the period October 28, 1964 through August 27, 1965 is presented in the form of charts for each solar rotation constructed from observations made with the chromospheric H-alpha spectra line. These H-alpha synoptic charts are identical in format and method of construction to those published for the period of Skylab observations. The sunspot minimum marking the start of Solar Cycle 20 occurred in October, 1964; therefore, charts represent solar activity during the first year of this solar cycle

    Optimal redesign study of the harm wing

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    The purpose of this project was to investigate the use of optimization techniques to improve the flutter margins of the HARM AGM-88A wing. The missile has four cruciform wings, located near mid-fuselage, that are actuated in pairs symmetrically and antisymmetrically to provide pitch, yaw, and roll control. The wings have a solid stainless steel forward section and a stainless steel crushed-honeycomb aft section. The wing restraint stiffness is dependent upon wing pitch amplitude and varies from a low value near neutral pitch attitude to a much higher value at off-neutral pitch attitudes, where aerodynamic loads lock out any free play in the control system. The most critical condition for flutter is the low-stiffness condition in which the wings are moved symmetrically. Although a tendency toward limit-cycle flutter is controlled in the current design by controller logic, wing redesign to improve this situation is attractive because it can be accomplished as a retrofit. In view of the exploratory nature of the study, it was decided to apply the optimization to a wing-only model, validated by comparison with results obtained by Texas Instruments (TI). Any wing designs that looked promising were to be evaluated at TI with more complicated models, including body modes. The optimization work was performed by McIntosh Structural Dynamics, Inc. (MSD) under a contract from TI

    PUTTING THE "ECON" INTO ECONOMETRICS

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    Should econometricians always incorporate economic theory in their models or only when unrestricted estimators are found to violate an inviolable theory? Using Monte Carlo experiments, we find that econometricians should use economic theory to the fullest extent possible. To paraphrase Leamer's classic article, we should put the "econ" into econometrics.Research Methods/ Statistical Methods,

    MULTIPRODUCT PRODUCTION CHOICES AND PESTICIDE REGULATION IN GEORGIA

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    An increasing emphasis on surface and groundwater quality and food safety may result in some form of pesticide regulations. A restricted profit function model of Georgia agriculture is used to examine the short-run effects of 2 and 5 percent reductions in all pesticides. Point estimates of short-run impacts, along with their 90 percent confidence intervals are presented.Agricultural and Food Policy,
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