4,937 research outputs found
A study of current guidance services in Massachusetts junior high schools
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
Emission Spectra from Internal Shocks in Gamma-Ray-Burst Sources
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
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 Jy at 1.43 GHz, and a spectral index,
, where . 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) of 90
M/yr, which gives a total SFR of M/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. 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 () 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
Some Combinatorial Properties of Hook Lengths, Contents, and Parts of Partitions
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
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
The nature of GRB-selected submillimeter galaxies: hot and young
We present detailed fits of the spectral energy distributions (SEDs) of four
submillimeter (submm) galaxies selected by the presence of a gamma-ray burst
(GRB) event (GRBs 980703, 000210, 000418 and 010222). These faint ~3 mJy submm
emitters at redshift ~1 are characterized by an unusual combination of long-
and short-wavelength properties, namely enhanced submm and/or radio emission
combined with optical faintness and blue colors. We exclude an active galactic
nucleus as the source of long-wavelength emission. From the SED fits we
conclude that the four galaxies are young (ages <2 Gyr), highly starforming
(star formation rates ~150 MSun/yr), low-mass (stellar masses ~10^10 MSun) and
dusty (dust masses ~3x10^8 MSun). Their high dust temperatures (Td>45 K)
indicate that GRB host galaxies are hotter, younger, and less massive
counterparts to submm-selected galaxies detected so far. Future facilities like
Herschel, JCMT/SCUBA-2 and ALMA will test this hypothesis enabling measurement
of dust temperatures of fainter GRB-selected galaxies.Comment: 9 pages, 2 figures, submitted to ApJ, for SED templates, see
http://archive.dark-cosmology.dk
All-weather ice information system for Alaskan arctic coastal shipping
A near real-time ice information system designed to aid arctic coast shipping along the Alaskan North Slope is described. The system utilizes a X-band Side Looking Airborne Radar (SLAR) mounted aboard a U.S. Coast Guard HC-130B aircraft. Radar mapping procedures showing the type, areal distribution and concentration of ice cover were developed. In order to guide vessel operational movements, near real-time SLAR image data were transmitted directly from the SLAR aircraft to Barrow, Alaska and the U.S. Coast Guard icebreaker Glacier. In addition, SLAR image data were transmitted in real time to Cleveland, Ohio via the NOAA-GOES Satellite. Radar images developed in Cleveland were subsequently facsimile transmitted to the U.S. Navy's Fleet Weather Facility in Suitland, Maryland for use in ice forecasting and also as a demonstration back to Barrow via the Communications Technology Satellite
Taking the Long Way Home: U.S. Tax Evasion and Offshore Investments in U.S. Equity and Debt Markets
We empirically investigate one form of illegal investor-level tax evasion and its effect on foreign portfolio investment. In particular, we examine a form of round-tripping tax evasion in which U.S. individuals hide funds in entities located in offshore tax havens and then invest those funds in U.S. securities markets. Employing Becker's (1968) economic theory of crime, we identify the tax evasion component by examining how foreign portfolio investment varies with changes in the incentives to evade and the risks of detection. To our knowledge, this is the first empirical evidence of investor-level tax evasion affecting cross-border equity and debt investment
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