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著者人数: 14名, Accepted: 2018-07-29, 資料番号: SA1180158000

著者人数: 19名, Accepted: 2018-05-10, 資料番号: SA1180192000

We have performed temperature (T) - dependent laser-photoemission spectroscopy of antiferromagnetic (AF) superconductor ErNi2B2C to study the electronic-structure evolution reflecting the interplay between antiferromagnetism and superconductivity. The spectra at the superconducting (SC) phase show a very broad spectral shape. T-dependent SC gap shows a sudden deviation from the BCS prediction just below TN. This observation can be well explained by the theoretical model and thus represents characteristic bulk electronic structure of the AF SC phase for the first time., Comment: 11 pages, 4 figures

The specific heat oscillation in the mixed state of type II superconductors is studied theoretically when rotating field within a plane containing gap minimum and maximum. The calculations are performed microscopically by solving quasi-classical Eilenberger equation for vortex lattices. The field dependence of the oscillation amplitude can discriminate between the nodal and anisotropic gap with a finite minimum and the oscillation phase gives the gap minimum position on the Fermi surface. These also provide a way to separate out the anisotropic behavior due to the Fermi velocity., Comment: 6 pages, 4 figures

It is well known that troglitazone and voluntary running have the capacity to improve insulin resistance. The purpose of this study was to evaluate the combination effect of troglitazone and voluntary running on insulin action. Female rats aged 7 weeks were divided into high-fat diet (HF), high-fat diet + troglitazone (0.3% in diet; Tg), high-fat diet + voluntary running (for 3 wks; Tr), high-fat diet + troglitazone + voluntary running (Tg-Tr), and control (C) groups. A sequential euglycemic clamp experiment with two different insulin infusion rates of 3.0 (L-clamp) and 30.0 mU/kg BW/min (H-clamp) was performed on these rats after an overnight fast. Blood glucose concentrations were kept at fasting levels by periodic adjustment of the intravenous glucose infusion rate during the clamp experiment. Glucose infusion rates (GIRs) calculated from 60 to 90, 150 to 180 min were regarded as an index of whole body insulin action. After the clamp experiment, we determined the amount of glycogen content in the gastrocnemius muscle. Fat feeding markedly reduced GIRs in both L- and H- clamp experiments compared with C. Troglitazone treatment did not improve high-fat induced insulin resistance. In both L- and H-clamp experiments, GIRs were increased by voluntary running compared with HF, and reached the same levels as in C. GIRs of Tg-Tr were not greater than those of Tr. Glycogen content in gastrocnemius muscle showed the same trend as the results for GIRs. Therefore, the combination effect of troglitazone and voluntary running on insulin action was not found, but the effect of voluntary running was shown in fat-induced insulin resistance.

We report new observations of molecular oxygen in absorption at z=0.685 in front of the radio source B0218+357. The lines at 56.3 and 118.7 GHz have been observed, redshifted to 33.4 and 70.5 GHz respectively, with the 12m at Kitt Peak, 43m at Green Bank telescopes, and the 45m Nobeyama radio telescope. Deriving the surface filling factor of the absorbing dark cloud with other lines detected at nearby frequencies, we deduce from the upper limits on the O2 lines a relative abundance of molecular oxygen with respect to carbon monoxyde of O2/CO $\la$ 2 10$^{-3}$ at 1$\sigma$, seven times lower than the previous limit. The consequences of this result are discussed., Comment: 4 pages, 3 figures, Letter accepted in Astron. & Astrophys

We present new J=1-0 12-CO observations along the northern spiral arm of the grand-design spiral galaxy M100 (NGC 4321), and study the distribution of molecular hydrogen as derived from these observations, comparing the new data with a set of data points on the southern arm published previously. We compare these measurements on both spiral arms and on the interarm regions with observations of the atomic and ionized hydrogen components. We determine massive star formation efficiency parameters, defined as the ratio of H alpha luminosity to total gas mass, along the arms and compare the values to those in the interarm regions adjacent to the arms. We find that these parameters in the spiral arms are on average a factor of 3 higher than outside the arms, a clear indication of triggering of the star formation in the spiral arms. We discuss possible mechanisms for this triggering, and conclude that a density wave system is probably responsible for it. We discuss several possible systematical effects in some detail, and infer that the conclusions on triggering are sound. We specifically discuss the possible effects of extinction in H alpha, or a non-standard CO to H_2 conversion factor (X), and find that our conclusions on the enhancement of the efficiencies in the arms are reinforced rather than weakened by these considerations. A simple star forming scheme involving threshold densities for gravitational collapse is discussed for NGC 4321, and comparison is made with M51. We find that the gas between the arms is generally stable against gravitational collapse whereas the gas in the arms is not, possibly leading to the observed arm-interarm differences in efficiency, but also note that these results, unlike the others obtained in this paper, do depend critically on the assumed value for the conversion factor., Comment: 14 pages, uuencoded compressed postscript file including six figures. Figure 3 (postscript) is available by anonymous ftp as ftp://ftp.astro.umontreal.ca/incoming/knapen/m100msfe/figure3.ps.gz, where the complete preprint is also stored. Accepted for publication in Astronomy & Astrophysics

The edge-on galaxy NGC 4565 has been observed in the 12CO(J=1-0)-line emission using the Nobeyama 45-m telescope with an angular resolution of 15". We obtained a scan along the major axis for +/-5' (+/- 15 kpc) about the galactic center, and some scans perpendicular to the galactic plane. The radial density distribution shows a dense molecular gas ring of 5 kpc radius, which is associated with an HI ring. The molecular disk comprises two components: an unresolved thin and dense disk, and a thick disk (or a halo) extending to a height greater than 1.4 kpc. The position-velocity diagram shows that the general rotation of the entire galaxy is circular with a flat rotation curve. However, the radial distribution of molecular gas is asymmetric with respect to the galaxy center in the sense that the molecular gas is much richer in the NW side. We derived a radial variation of \htwo-to-(HI+ \htwo) density ratio, and found that int erstellar gas in the central 4 kpc region is almost entirely H2, while HI is dominant beyond 10 kpc. A similar HI-vs-\htwo\ behavior was found in the edge-on galaxy NGC 891., Comment: (to appear in PASJ), plainTeX, 9pages, U-Tokyo Astro. No. 92-28