305 research outputs found
Role of a Japanese Market for New Japanese Migrants in the United States
This research paper seeks to provide a clearer understanding of contemporary Japanese migration to the United States through a case study examining the role of one Japanese market, Nijiya Market, in Sawtelle, Los Angeles. This study identifies the main roles that this particular market serves, as evidenced by oral interviews and intensive site observation fieldwork. The findings reveal that the ethnic market is very important to the creation and maintenance of ethnic identity across multiple generations of new Japanese immigrants and migrants living in the United States. Furthermore, as a main component of many Japanese communities, the ethnic market enables Japanese to maintain aspects of their homeland lifestyle and culture, even while living abroad. Perhaps most importantly, they provide these Japanese with a way to extend a bridge between their lives in the United States and their lives in Japan
The New Movement of Active Learning in Japanese Higher Education: The Analysis of Active Learning Case in Japanese Graduate Programs
Currently, active learning becomes the major concern for Japanese higher education institutions. In this chapter, active learning is defined that students study with clear purposes and are engaged in learning proactively. As a result, active learning brings some learning outcomes. Many previous studies have shown that the learning outcomes of students are strongly associated with the quality of pedagogy and student experience. Such pedagogy often includes active learning methods, and it is often expected that active learning methods are strongly associated with proactive learning of students. Such active learning methods have been introduced in the Japanese graduate programs so called leading graduate programs. In this chapter, after examining the theory and effectiveness of active learning, we will examine the practice of active learning methods introduced in leading graduate program of University of Tsukuba. That program is unique and interdisciplinary programs, which will lead to learning outcomes sought in the new knowledge-based society
Explosive Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars II. Heavy-Element Nucleosynthesis of s, r, p-Processes
We investigate the nucleosynthesis in a massive star of 70 M_solar with solar
metallicity in the main sequence stage. The helium core mass after hydrogen
burning corresponds to 32 M_solar. Nucleosynthesis calculations have been
performed during the stellar evolution and the jetlike supernova explosion of a
collapsar model, where the weak s-, p-, and r-processes are taken into account.
We confirm that s-elements of 60 < A < 90 are highly overproduced relative to
the solar abundances in the hydrostatic nucleosynthesis. During oxygen burning,
p-elements of A > 90 are produced via photodisintegrations of seed s-elements.
However, the produced p-elements are disintegrated in later stages except for
^{180}Ta. In the explosive nucleosynthesis, elements of 90 < A < 160 are
significantly overproduced relative to the solar values owing to the r-process.
Only heavy p-elements (N > 50) are overproduced via the p-process. Compared
with the previous study of r-process nucleosynthesis calculations in the
collapsar model of 40 M_solar by Fujimoto et al. 2007, 2008, our jet model
cannot contribute to the third peak of the solar r-elements and intermediate
p-elements. Averaging the overproduction factors over the progenitor masses
with the use of Salpeter's IMF, we suggest that the 70 M_solar star could
contribute to the solar weak s-elements of 60 < A < 90 and neutron-rich
elements of 90 < A < 160. We confirm the primary synthesis of light p-elements
in the ejected matter of high peak temperature. The ejected matter has [Sr/Eu]
\sim -0.4, which is different from that of a typical r-process-enriched star
CS22892-052 ([Sr/Eu] \sim -1). We find that Sr-Y-Zr isotopes are primarily
synthesized in the explosive nucleosynthesis in a similar process of the
primary production of light p-elements, which has been considered as one of the
sites of a lighter element primary process (LEPP).Comment: 25 pages, 13 figures, 2 tables, accepted for publication in Progress
of Theoretical Physic
Application of spectral methods for high-frequency financial data to quantifying states of market participants
Empirical analysis of the foreign exchange market is conducted based on
methods to quantify similarities among multi-dimensional time series with
spectral distances introduced in [A.-H. Sato, Physica A, 382 (2007) 258--270].
As a result it is found that the similarities among currency pairs fluctuate
with the rotation of the earth, and that the similarities among best quotation
rates are associated with those among quotation frequencies. Furthermore it is
shown that the Jensen-Shannon spectral divergence is proportional to a mean of
the Kullback-Leibler spectral distance both empirically and numerically. It is
confirmed that these spectral distances are connected with distributions for
behavioral parameters of the market participants from numerical simulation.
This concludes that spectral distances of representative quantities of
financial markets are related into diversification of behavioral parameters of
the market participants.Comment: 8 pages, 6 figures, APFA
Magnetohydrodynamic Simulations of A Rotating Massive Star Collapsing to A Black Hole
We perform two-dimensional, axisymmetric, magnetohydrodynamic simulations of
the collapse of a rotating star of 40 Msun and in the light of the collapsar
model of gamma-ray burst. Considering two distributions of angular momentum, up
to \sim 10^{17} cm^2/s, and the uniform vertical magnetic field, we investigate
the formation of an accretion disk around a black hole and the jet production
near the hole. After material reaches to the black hole with the high angular
momentum, the disk is formed inside a surface of weak shock. The disk becomes
in a quasi-steady state for stars whose magnetic field is less than 10^{10} G
before the collapse. We find that the jet can be driven by the magnetic fields
even if the central core does not rotate as rapidly as previously assumed and
outer layers of the star has sufficiently high angular momentum. The magnetic
fields are chiefly amplified inside the disk due to the compression and the
wrapping of the field. The fields inside the disk propagate to the polar region
along the inner boundary near the black hole through the Alfv{\'e}n wave, and
eventually drive the jet. The quasi-steady disk is not an advection-dominated
disk but a neutrino cooling-dominated one. Mass accretion rates in the disks
are greater than 0.01 Msun/sec with large fluctuations. The disk is transparent
for neutrinos. The dense part of the disk, which locates near the hole, emits
neutrino efficiently at a constant rate of < 8 \times 10^{51} erg/s. The
neutrino luminosity is much smaller than those from supernovae after the
neutrino burst.Comment: 42 pages, accepted for publication in the Astrophysical Journal. A
paper with higher-resolution figures available at
http://www.ec.knct.ac.jp/~fujimoto/collapsar/mhd-color.pd
Formation of naked singularities in five-dimensional space-time
We numerically investigate the gravitational collapse of collisionless
particles in spheroidal configurations both in four and five-dimensional (5D)
space-time. We repeat the simulation performed by Shapiro and Teukolsky (1991)
that announced an appearance of a naked singularity, and also find that the
similar results in 5D version. That is, in a collapse of a highly prolate
spindle, the Kretschmann invariant blows up outside the matter and no apparent
horizon forms. We also find that the collapses in 5D proceed rapidly than in
4D, and the critical prolateness for appearance of apparent horizon in 5D is
loosened compared to 4D cases. We also show how collapses differ with spatial
symmetries comparing 5D evolutions in single-axisymmetry, SO(3), and those in
double-axisymmetry, U(1)U(1).Comment: 5 pages, 5 figures, To be published in Phys. Rev.
R-Process Nucleosynthesis in MHD Jet Explosions of Core-Collapse Supernovae
We investigate -process nucleosynthesis during the magnetohydrodynamical
(MHD) explosion of supernova in a massive star of 13 . Contrary to
the case of the spherical explosion, jet-like explosion due to the combined
effects of the rotation and magnetic field lowers the electron fraction
significantly inside the layers above the iron core. We find that the ejected
material of low electron fraction responsible for the -process comes out
from the silicon rich layer of the presupernova model. This leads to the
production up to the third peak in the solar -process elements. We examine
whether the fission affects the -process paths by using the full nuclear
reaction network with both the spontaneous and -delayed fission
included. Moreover, we pay particular attention how the mass formula affects
the -process peaks with use of two mass formulae. It is found that both
formulae can reproduce the global abundance pattern up to the third peak though
detailed distributions are rather different. We point out that there are
variations in the -process nucleosynthesis if the MHD effects play an
important role in the supernova explosion.Comment: 19 pages with 7 figures, submitted to Ap
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