5,110 research outputs found
Infrared 3-4 Micron Spectroscopy of Nearby PG QSOs and AGN-Nuclear Starburst Connections in High-luminosity AGN Populations
We present the results of infrared L-band (3-4 micron) slit spectroscopy of
30 PG QSOs at z < 0.17, the representative sample of local high-luminosity,
optically selected AGNs. The 3.3 micron polycyclic aromatic hydrocarbon (PAH)
emission feature is used to probe nuclear (< a few kpc) starburst activity and
to investigate the connections between AGNs and nuclear starbursts in PG QSOs.
The 3.3 micron PAH emission is detected in the individual spectra of 5/30 of
the observed PG QSOs. We construct a composite spectrum of PAH-undetected PG
QSOs and discern the presence of the 3.3 micron PAH emission therein. We
estimate the nuclear-starburst and AGN luminosities from the observed 3.3
micron PAH emission and 3.35 micron continuum luminosities, respectively, and
find that the nuclear-starburst-to-AGN luminosity ratios in PG QSOs are similar
to those of previously studied AGN populations with lower luminosities,
suggesting that AGN-nuclear starburst connections are valid over the wide
luminosity range of AGNs in the local universe. The observed
nuclear-starburst-to-AGN luminosity ratios in PG QSOs with available
supermassive black hole masses are comparable to a theoretical prediction based
on the assumption that the growth of a supermassive black hole is controlled by
starburst-induced turbulence.Comment: 10 pages, 5 figures, accepted for publication in PASJ (No. 63, 2011
March, Subaru special issue
Effective motivational strategies for English classes in Japan (2) : based on questionnaires to teachers and students
The present article aims at exploring effective motivational strategies through investigating how junior high and senior high school students are motivated by the strategies. The questionnaire titled "Research on attitudes toward English classes and English learning" with the same 50 items utilized in the questionnaire for teachers in the previous article (1) (Narikawa and Okazaki, 2011) was administered to 223 junior high school and 492 senior high school students. Two remarkable findings were discovered: one is that both junior and senior high school students hope for more opportunities in which they can use English than they presently have and the other is that strategies for promoting extrinsic motivation can be effective for students who seem not to have high motivation for learning English. The pedagogical implications suggest Japanese English teachers can motivate their students if they increase the opportunities inside and outside classes in which students can actually use English, and that teachers can utilize extrinsic motivation more effectively
Sudden changes in volatility: The case of five central European stock markets
This is the post-print version of the final paper published in Journal of International Financial Markets, Institutions and Money. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2007 Elsevier B.V.This paper investigates sudden changes in volatility in the stock markets of new European Union (EU) members by utilizing the iterated cumulative sums of squares (ICSS) algorithm. Using weekly data over the sample period 1994–2006, the time period of sudden change in variance of returns and the length of this variance shift are detected. A sudden change in volatility seems to arise from the evolution of emerging stock markets, exchange rate policy changes and financial crises. Evidence also reveals that when sudden shifts are taken into account in the GARCH models, the persistence of volatility is reduced significantly in every series. It suggests that many previous studies may have overestimated the degree of volatility persistence existing in financial time series
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