834 research outputs found

    Magnon scattering processes and low temperature resistivity in CMR manganites

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    Low temperature resistivity of CMR manganites is investigated. At the ground state, conduction electrons are perfectly spin polarized, which is called half-metallic. From one-magnon scattering processes, it is discussed that the resistivity of a half metal as a function of temperature scales as rho(T) - rho(0) propto T^3. We take (Nd,Tb,Sr)MnO_3 as an example to compare theory and experiments. The result is in a good agreement.Comment: To appear in Proc. ICM 200

    Age and Dust Degeneracy for Starburst Galaxies Solved?

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    A spectral evolution model of galaxies that includes both stellar and dust effects is newly built. xApplying the model to 22 nearby starburst galaxies, we have shown that far infrared luminosity of galaxies helps to break the age-dustiness degeneracy. We have derived a unique solution of age and the dustiness for each starburst galaxy. The resulting starburst ages and optical depths are in the range 10t(Myr)50010 \le t (Myr) \le 500 and 0.5τV5.00.5 \le \tau_{V} \le 5.0, respectively. The result is robust and is almost independent of model assumptions such as dust distributions, extinction curves, and burst strengths. With the rapidly growing sensitivity of submillimeter detectors, it should become possible in the near future to determine the age and τV\tau_{V} of star-forming galaxies at redshifts z3z \simeq 3 and beyond. Accurate estimates of τV\tau_{V} for Lyman-break galaxies and high-z galaxies might require a substantial revision of the previously claimed picture of star formation history over the Hubble time.Comment: Latex (aas2pp4) 15 pages, 1 table, 6 figures. Accepted for Ap

    Clustering of red Galaxies near the Radio-loud Quasar 1335.8+2834 at z=1.1

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    We have obtained new deep optical and near-infrared images of the field of the radio-loud quasar 1335.8+2834 at z=1.086z=1.086 where an excess in the surface number density of galaxies was reported by Hutchings et al. [AJ, 106, 1324] from optical data. We found a significant clustering of objects with very red optical-near infrared colors, 4RK64 \lesssim R-K \lesssim 6 and 3IK53 \lesssim I-K \lesssim 5 near the quasar. The colors and magnitudes of the reddest objects are consistent with those of old (12 Gyr old at z=0) passively-evolving elliptical galaxies seen at z=1.1z=1.1, clearly defining a `red envelope' like that found in galaxy clusters at similar or lower redshifts. This evidence strongly suggests that the quasar resides in a moderately-rich cluster of galaxies (richness-class 0\geq 0). There is also a relatively large fraction of objects with moderately red colors (3.5<RK<4.53.5 < R-K < 4.5) which have a distribution on the sky similar to that of the reddest objects. They may be interpreted as cluster galaxies with some recent or on-going star formation.Comment: 14 pages text, 5 PostScript figures, 1 GIF figure, and 1 combined PS file. Accepted for ApJ, Letter

    Development of the Japanese version of the health‐related quality of life questionnaire for bladder cancer patients using the Bladder Cancer Index: A pilot study

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151958/1/iju14073.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151958/2/iju14073_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151958/3/iju14073-sup-0003-app2.pd

    Effective meson masses, effective meson-nucleon couplings and neutron star radii

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    Using the generalized mean field theory, we have studied the relation among the effective meson masses, the effective meson-nucleon couplings and the equation of state (EOS) in asymmetric nuclear matter. If the effective omega-meson mass becomes smaller at high density, the EOS becomes stiffer. However, if we require that the omega-meson mean field is proportional to the baryon density, the effective omega-nucleon coupling automatically becomes smaller at the same time as the effective omega-meson mass becomes smaller. Consequently, the EOS becomes softer. A similar relation is found for the effective rho-meson mass and the effective rho-nucleon coupling. We have also studied the relation among the effective meson masses, the effective meson-nucleon couplings and a radius R of a neutron star. The R depends somewhat on the value of the effective omega-meson mass and the effective omega-nucleon coupling.Comment: 29pages, 24 figure

    Using Weak Lensing Dilution to Improve Measurements of the Luminous and Dark Matter in A1689

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    The E/SO sequence of a cluster defines a boundary redward of which a reliable weak lensing signal can be obtained from background galaxies, uncontaminated by cluster members. For bluer colors, both background and cluster members are present, reducing the distortion signal by the proportion of unlensed cluster members. In deep Subaru and HST/ACS images of A1689 the tangential distortion of galaxies with bluer colors falls rapidly toward the cluster center relative to the lensing signal of the red background. We use this dilution effect to derive the cluster light profile and luminosity function to large radius, with the advantage that no subtraction of far-field background counts is required. The light profile declines smoothly to the limit of the data, r<2Mpc/h, with a constant slope, dlog(L)/dlog(r)=-1.12+-0.06, unlike the lensing mass profile which steepens continuously with radius, so that M/L peaks at an intermediate radius, ~100kpc/h. A flatter behavior is found for the more physically meaningful ratio of dark-matter to stellar-matter, when accounting for the color-mass relation of cluster members. The cluster luminosity function has a flat slope, alpha=-1.05+-0.07, independent of radius and with no faint upturn to M_i'<-12. We establish that the very bluest objects are negligibly contaminated by the cluster V-i'<0.2, because their distortion profile rises towards the center following the red background, but offset higher by ~20%. This larger amplitude is consistent with the greater estimated depth of the faint blue galaxies, z~=2.0 compared to z~=0.85 for the red background, a purely geometric effect related to cosmological parameters. Finally, we improve upon our earlier mass profile by combining both the red and blue background populations, clearly excluding low concentration CDM profiles.Comment: 17 pages, 21 figures, revised version in response to referee comments,(added some discussion, references), conclusions unchanged. Accepted for publication in Ap

    Quark condensate in nuclear matter based on Nuclear Schwinger-Dyson formalism

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    The effects of higher order corrections of ring diagrams for the quark condensate are studied by using the bare vertex Nuclear Schwinger Dyson formalism based on σ\sigma-ω\omega model. At the high density the quark condensate is reduced by the higher order contribution of ring diagrams more than the mean field theory or the Hartree-Fock

    New Near-Infrared Spectroscopy of the High Redshift Quasar B 1422+231 at z=3.62

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    We present new near-infrared (rest-frame UV-to-optical) spectra of the high redshift, gravitationally lensed quasar B 1422+231 (z=3.62). Diagnostic emission lines of FeII, [OIII]5007, and Hb, commonly used to determine the excitation, ionization, and chemical abundances of radio-quiet and radio-loud quasars, were detected. Our new data show that the ratio FeII(UV)/Hb=18.1+-4.6 and FeII(optical)/Hb=2.3+-0.6 are higher than those reported by Kawara et al. (1996) by factors of 1.6 and 3.3, respectively, although the ration [OIII]5007/Hb=0.19+-0.02 is nearly the same between the two measurements. The discrepancy of the line flux ratios between the measurements is likely due to improved data and fitting procedures rather that to intrinsic variability. While approximately half of the high-z quasars observed to date have much more extreme FeII(optical)/Hb ratios, the line ratio measured for B 422+231 are consistent with the observed range of FeII(optical) ratios of low-z quasars.Comment: 5 pages, 1 table, 4 figures. To appear in The Astronomical Journa
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