6,713 research outputs found

    A study of current guidance services in Massachusetts junior high schools

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    Thesis (Ed.M.)--Boston UniversityIt was the purpose of this study: (1) to determine the scope, design and function of guidance services in the Massachusetts Junior High Schools; (2)to disclose the procedure followed in tho administration of guidance services under five major categories : counseling; individual inventory; information (education-occupation); placement; and follow-up; (3) to determine whether the need for a broader program of guidance exists because of the recent emphasis being places on the establishment of more Junior high schools throughout the state

    Apollo 7 retrofire and reentry of service propulsion module. Further study of Intelsat 2 F-2 apogee burn

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    Photography of Apollo 7 retrofire and service propulsion module reentry and apogee burn of Intelsat 2 F-2 satellit

    Emission Spectra from Internal Shocks in Gamma-Ray-Burst Sources

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    Unsteady activity of gamma-ray burst sources leads to internal shocks in their emergent relativistic wind. We study the emission spectra from such shocks, assuming that they produce a power-law distribution of relativistic electrons and posses strong magnetic fields. The synchrotron radiation emitted by the accelerated electrons is Compton up-scattered multiple times by the same electrons. A substantial component of the scattered photons acquires high energies and produces e+e- pairs. The pairs transfer back their kinetic energy to the radiation through Compton scattering. The generic spectral signature from pair creation and multiple Compton scattering is highly sensitive to the radius at which the shock dissipation takes place and to the Lorentz factor of the wind. The entire emission spectrum extends over a wide range of photon energies, from the optical regime up to TeV energies. For reasonable values of the wind parameters, the calculated spectrum is found to be in good agreement with the burst spectra observed by BATSE.Comment: 12 pages, latex, 2 figures, submitted to ApJ

    The Host Galaxy of GRB980703 at Radio Wavelengths - a Nuclear Starburst in a ULIRG

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    We present radio observations of GRB980703 at 1.43, 4.86, and 8.46 GHz for the period of 350 to 1000 days after the burst. These radio data clearly indicate that there is a persistent source at the position of GRB980703 with a flux density of approximately 70 μ\muJy at 1.43 GHz, and a spectral index, β0.32\beta\approx 0.32, where FννβF_\nu\propto \nu^{-\beta}. We show that emission from the afterglow of GRB980703 is expected to be one to two orders of magnitude fainter, and therefore cannot account for these observations. We interpret this persistent emission as coming from the host galaxy --- the first example of a gamma-ray burst (GRB) host detection at radio wavelengths. We show that emission from an AGN is unlikely, and find that it can be explained as a result of a star-formation rate (SFR) of massive stars (M>5M_\odot) of 90 M_\odot/yr, which gives a total SFR of 500\approx 500 M_\odot/yr. Using the correlation between the radio and far-IR (FIR) luminosities of star-forming galaxies, we find that the host of GRB980703 is at the faint end of the class of Ultra Luminous Infrared Galaxies (ULIRGs), with L_{FIR}\sim few\times 10^{12} L_\odot. From the radio measurements of the offset between the burst and the host, and the size of the host, we conclude that GRB980703 occurred near the center of the galaxy in a region of maximum star formation. A comparison of the properties of this galaxy with radio and optical surveys at a similar redshift (z1z\approx 1) reveals that the host of GRB980703 is an average star-forming galaxy. This result has significant implications for the potential use of a GRB-selected galaxy sample for the study of galaxies and the IGM at high redshifts.Comment: Submitted to Ap

    Interferometric phase-dispersion microscopy

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    We describe a new scanning microscopy technique, phase-dispersion microscopy (PDM). The technique is based on measuring the phase difference between the fundamental and the second-harmonic light in a novel interferometer. PDM is highly sensitive to subtle refractive-index differences that are due to dispersion (differential optical path sensitivity, 5 nm). We apply PDM to measure minute amounts of DNA in solution and to study biological tissue sections. We demonstrate that PDM performs better than conventional phase-contrast microscopy in imaging dispersive and weakly scattering samples

    Some Combinatorial Properties of Hook Lengths, Contents, and Parts of Partitions

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    This paper proves a generalization of a conjecture of Guoniu Han, inspired originally by an identity of Nekrasov and Okounkov. The main result states that certain sums over partitions p of n, involving symmetric functions of the squares of the hook lengths of p, are polynomial functions of n. A similar result is obtained for symmetric functions of the contents and shifted parts of n.Comment: 20 pages. Correction of some inaccuracies, and a new Theorem 4.

    Barriers to Mobility: The Lockout Effect of U.S. Taxation of Worldwide Corporate Profits

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    Using data from a survey of tax executives, we examine the corporate response to the one-time dividends received deduction in the American Jobs Creation Act of 2004. We describe the firms’ reported sources and uses of the cash repatriated and we also examine non-tax costs companies incurred to avoid the repatriation tax prior to the Act. Finally, we examine whether firms would repatriate cash again if a similar Act were to occur in the future. Overall, the evidence is consistent with a substantial lockout effect resulting from the current U.S. policy of taxing the worldwide profits of U.S. multinationals.Fuqua School of Business (Duke University)Michigan Ross School of Business (Paton Accounting Fund)University of Washington (Paul Pigott/PACCAR Professorship

    Real Effects of Accounting Rules: Evidence from Multinational Firms' Investment Location and Profit Repatriation Decisions

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    We analyze survey responses from nearly 600 tax executives to better understand corporate decisions about real investment location and profit repatriation. Our evidence indicates that avoiding financial accounting income tax expense is as important as avoiding cash income taxes when corporations decide where to locate operations and whether to repatriate foreign earnings. This result is important in light of the recent research about whether financial accounting affects investment and in light of the decades of research on foreign investment that examines the role of cash income taxes but heretofore has not investigated the importance of financial reporting effects. Our analysis suggests that financial reporting is an important factor to be considered in the policy debates focused on bringing investment to the United States
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