6,953 research outputs found

    Twenty Years of Revisionism

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    It would seem most natural that the 1947 Constitution of Japan should have been the target of strong revisionist pressure in the years following its promulgation, considering its contents and the special circumstances of its making. However, looking back upon the developments in this revisionist movement, one is struck by the degree of ambivalence and confusion in the attitudes of both the proponents. and opponents of revision and by the apparent failure of the former to effect revision. It is my view that these two impressions are very intimately interrelated and that an understanding of this relationship is necessary if the issues involved are to be viewed in historical perspective. I also feel that it is helpful to focus on two broad aspects of the revisionist movement, one relating to its typological composition and ideological implications and the other to the nature and scope of its support

    Recombining Plasma & Gamma-ray Emission in the Mixed-morphology Supernova Remnant 3C 400.2

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    3C 400.2 belongs to the mixed morphology supernova remnant class, showing center-filled X-ray and shell-like radio morphology. We present a study of 3C 400.2 with archival Suzaku and Fermi-LAT observations. We find recombining plasma (RP) in the Suzaku spectra of north-east and south-east regions. The spectra of these regions are well described by two-component thermal plasma models: The hard component is in RP, while the soft component is in collisional ionization equilibrium (CIE) conditions. The RP has enhanced abundances indicating that the X-ray emission has an ejecta origin, while the CIE has solar abundances associated with the interstellar material. The X-ray spectra of north-west and south-west regions are best fitted by a two-component thermal plasma model: an ionizing and a CIE plasma. We have detected GeV gamma-ray emission from 3C 400.2 at the level of ∼\sim5σ\sigma assuming a point-like source model with a power-law (PL) type spectrum. We have also detected a new GeV source at the level of ∼\sim13σ\sigma assuming a Gaussian extension model with a PL type spectrum in the neighborhood of the SNR. We report the analysis results of 3C 400.2 and the new extended gamma-ray source and discuss the nature of gamma-ray emission of 3C 400.2 in the context of existing NANTEN CO data, DRAO HI data, and the Suzaku X-ray analysis results.Comment: Accepted to be published in the Astrophysical Journa

    Observations of [C II] 158 micron Line and Far-infrared Continuum Emission toward the High-latitude Molecular Clouds in Ursa Major

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    We report the results of a rocket-borne observation of [C II] 158\micron line and far-infrared continuum emission at 152.5\micron toward the high latitude molecular clouds in Ursa Major. We also present the results of a follow-up observation of the millimeter ^{12}CO J=1-0 line over a selected region observed by the rocket-borne experiment. We have discovered three small CO cloudlets from the follow-up ^{12}CO observations. We show that these molecular cloudlets, as well as the MBM clouds(MBM 27/28/29/30), are not gravitationally bound. Magnetic pressure and turbulent pressure dominate the dynamic balance of the clouds. After removing the HI-correlated and background contributions, we find that the [C II] emission peak is displaced from the 152.5\micron and CO peaks, while the 152.5\micron continuum emission is spatially correlated with the CO emission. We interpret this behavior by attributing the origin of [C II] emission to the photodissociation regions around the molecular clouds illuminated by the local UV radiation field. We also find that the ratio of the molecular hydrogen column density to velocity-integrated CO intensity is 1.19+-0.29x10^{20} cm^{-2} (K kms^{-1})^{-1} from the FIR continuum and the CO data. The average [C II] /FIR intensity ratio over the MBM clouds is 0.0071, which is close to the all sky average of 0.0082 reported by the FIRAS on the COBE satellite. The average [C II]/CO ratio over the same regions is 420, which is significantly lower than that of molecular clouds in the Galactic plane.Comment: 15 pages, LaTeX (aaspp4.sty) + 2 tables(apjpt4.sty) + 6 postscript figures; accepted for publication in the Astrophysical Journal; Astrophys. J. in press (Vol. 490, December 1, 1997 issue

    Star Forming Dense Cloud Cores in the TeV {\gamma}-ray SNR RX J1713.7-3946

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    RX J1713.7-3946 is one of the TeV {\gamma}-ray supernova remnants (SNRs) emitting synchrotron X rays. The SNR is associated with molecular gas located at ~1 kpc. We made new molecular observations toward the dense cloud cores, peaks A, C and D, in the SNR in the 12CO(J=2-1) and 13CO(J=2-1) transitions at angular resolution of 90". The most intense core in 13CO, peak C, was also mapped in the 12CO(J=4-3) transition at angular resolution of 38". Peak C shows strong signs of active star formation including bipolar outflow and a far-infrared protostellar source and has a steep gradient with a r^{-2.2±\pm0.4} variation in the average density within radius r. Peak C and the other dense cloud cores are rim-brightened in synchrotron X rays, suggesting that the dense cloud cores are embedded within or on the outer boundary of the SNR shell. This confirms the earlier suggestion that the X rays are physically associated with the molecular gas (Fukui et al. 2003). We present a scenario where the densest molecular core, peak C, survived against the blast wave and is now embedded within the SNR. Numerical simulations of the shock-cloud interaction indicate that a dense clump can indeed survive shock erosion, since shock propagation speed is stalled in the dense clump. Additionally, the shock-cloud interaction induces turbulence and magnetic field amplification around the dense clump that may facilitate particle acceleration in the lower-density inter-clump space leading to the enhanced synchrotron X rays around dense cores.Comment: 22 pages, 7 figures, to accepted in The Astrophysical Journal. A full color version with higher resolution figures is available at http://www.a.phys.nagoya-u.ac.jp/~sano/ApJ10/ms_sano.pd

    The impact of aviation fuel tax on fuel consumption and carbon emissions: The case of the US airline industry

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    We examine the effect of an increase in aviation fuel tax on reductions in fuel consumption and carbon emissions using data from the US airline industry. The results of simultaneous quantile regression using an unbalanced annual panel of US carriers from 1995 to 2013 suggest that the short-run price elasticities of jet fuel consumption, which are negative and statistically significant for all quantiles, vary from −0.350 to −0.166. The long-run price elasticities show a similar pattern and vary from −0.346 to −0.166, though they are statistically significant only for the 0.1, 0.2, 0.3, and 0.5 quantiles. The results suggest that the amount of the reduction of fuel consumption and CO2 emissions would be smaller in the longer term. Our calculation, using values from 2012, suggests that an increase in aviation fuel tax of 4.3 cents, which was the highest increase in aviation fuel tax in the US during the analysis period, would reduce CO2 emissions in the US by approximately 0.14–0.18% in the short run (1 year after the tax increase). However, perhaps due to the rebound effect, the percentage reduction in CO2 emissions would decrease to about 0.008–0.01% in the long run (3 years after the tax increase)

    An edge index for the Quantum Spin-Hall effect

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    Quantum Spin-Hall systems are topological insulators displaying dissipationless spin currents flowing at the edges of the samples. In contradistinction to the Quantum Hall systems where the charge conductance of the edge modes is quantized, the spin conductance is not and it remained an open problem to find the observable whose edge current is quantized. In this paper, we define a particular observable and the edge current corresponding to this observable. We show that this current is quantized and that the quantization is given by the index of a certain Fredholm operator. This provides a new topological invariant that is shown to take same values as the Spin-Chern number previously introduced in the literature. The result gives an effective tool for the investigation of the edge channels' structure in Quantum Spin-Hall systems. Based on a reasonable assumption, we also show that the edge conducting channels are not destroyed by a random edge.Comment: 4 pages, 3 figure

    Topological Description of (Spin) Hall Conductances on Brillouin Zone Lattices : Quantum Phase Transitions and Topological Changes

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    It is widely accepted that topological quantities are useful to describe quantum liquids in low dimensions. The (spin) Hall conductances are typical examples. They are expressed by the Chern numbers, which are topological invariants given by the Berry connections of the ground states. We present a topological description for the (spin) Hall conductances on a discretized Brillouin Zone. At the same time, it is quite efficient in practical numerical calculations for concrete models. We demonstrate its validity in a model with quantum phase transitions. Topological changes supplemented with the transition is also described in the present lattice formulation.Comment: proceeding of EP2DS-1
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