3,872 research outputs found

    An investigation of children's peer trust across culture: is the composition of peer trust universal?

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    The components of children's trust in same-gender peers (trust beliefs, ascribed trustworthiness, and dyadic reciprocal trust) were examined in samples of 8- to 11-year-olds from the UK, Italy, and Japan. Trust was assessed by children's ratings of the extent to which same-gender classmates kept promises and kept secrets. Social relations analyses confirmed that children from each country showed significant: (a) actor variance demonstrating reliable individual differences in trust beliefs, (b) partner variance demonstrating reliable individual differences in ascribed trustworthiness, and (c ) relationship variance demonstrating unique relationships between interaction partners. Cultural differences in trust beliefs and ascribed trustworthiness also emerged and these differences were attributed to the tendency for children from cultures that value societal goals to share personal information with the peer group

    The Phase Diagram of the U(2)×U(2)U(2)\times U(2) Sigma Model

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    We study the phase diagram of the U(2)×U(2)U(2) \times U(2) scalar model in d=4d=4 dimensions. We find that the phase transition is of first order in most of the parameter space. The theory can still be relevant to continuum physics (as an effective theory) provided the transition is sufficiently weakly first order. This places restrictions on the allowed coupling constants.Comment: 3 pages (Latex), 2 eps figures, uses espcrc2.sty, epsf, talk given at LATTICE9

    Tunneling in graphene-topological insulator hybrid devices

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    Hybrid graphene-topological insulator (TI) devices were fabricated using a mechanical transfer method and studied via electronic transport. Devices consisting of bilayer graphene (BLG) under the TI Bi2_2Se3_3 exhibit differential conductance characteristics which appear to be dominated by tunneling, roughly reproducing the Bi2_2Se3_3 density of states. Similar results were obtained for BLG on top of Bi2_2Se3_3, with 10-fold greater conductance consistent with a larger contact area due to better surface conformity. The devices further show evidence of inelastic phonon-assisted tunneling processes involving both Bi2_2Se3_3 and graphene phonons. These processes favor phonons which compensate for momentum mismatch between the TI Γ\Gamma and graphene K,Kâ€ČK, K' points. Finally, the utility of these tunnel junctions is demonstrated on a density-tunable BLG device, where the charge-neutrality point is traced along the energy-density trajectory. This trajectory is used as a measure of the ground-state density of states

    Dust properties in the cold and hot gas phases of the ATLAS3D early-type galaxies as revealed by AKARI

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    The properties of the dust in the cold and hot gas phases of early-type galaxies (ETGs) are key to understand ETG evolution. We thus conducted a systematic study of the dust in a large sample of local ETGs, focusing on relations between the dust and the molecular, atomic, and X-ray gas of the galaxies, as well as their environment. We estimated the dust temperatures and masses of the 260 ETGs from the ATLAS3D survey, using fits to their spectral energy distributions primarily constructed from AKARI measurements. We also used literature measurements of the cold (CO and HI) and X-ray gas phases. Our ETGs show no correlation between their dust and stellar masses, suggesting inefficient dust production by stars and/or dust destruction in X-ray gas. The global dust-to-gas mass ratios of ETGs are generally lower than those of late-type galaxies, likely due to dust-poor HI envelopes in ETGs. They are also higher in Virgo Cluster ETGs than in group and field ETGs, but the same ratios measured in the central parts of the galaxies only are independent of galaxy environment. Slow-rotating ETGs have systematically lower dust masses than fast-rotating ETGs. The dust masses and X-ray luminosities are correlated in fast-rotating ETGs, whose star formation rates are also correlated with the X-ray luminosities. The correlation between dust and X-rays in fast-rotating ETGs appears to be caused by residual star formation, while slow-rotating ETGs are likely well evolved, and thus exhausting their dust. These results appear consistent with the postulated evolution of ETGs, whereby fast-rotating ETGs form by mergers of late-type galaxies and associated bulge growth, while slow-rotating ETGs form by (dry) mergers of fast-rotating ETGs. Central cold dense gas appears to be resilient against ram pressure stripping, suggesting that Virgo Cluster ETGs may not suffer strong related star formation suppression.Comment: 18 pages, 7 figures, accepted for publication in A&

    Large-scale distributions of mid- and far-infrared emission from the center to the halo of M82 revealed with AKARI

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    The edge-on starburst galaxy M82 exhibits complicated distributions of gaseous materials in its halo, which include ionized superwinds driven by nuclear starbursts, neutral materials entrained by the superwinds, and large-scale neutral streamers probably caused by a past tidal interaction with M81. We investigate detailed distributions of dust grains and polycyclic aromatic hydrocarbons (PAHs) around M82 to understand their interplay with the gaseous components. We performed mid- (MIR) and far-infrared (FIR) observations of M82 with the Infrared Camera and Far-Infrared Surveyor on board AKARI. We obtain new MIR and FIR images of M82, which reveal both faint extended emission in the halo and very bright emission in the center with signal dynamic ranges as large as five and three orders of magnitude for the MIR and FIR, respectively. We detect MIR and FIR emission in the regions far away from the disk of the galaxy, reflecting the presence of dust and PAHs in the halo of M82. We find that the dust and PAHs are contained in both ionized and neutral gas components, implying that they have been expelled into the halo of M82 by both starbursts and galaxy interaction. In particular, we obtain a tight correlation between the PAH and Hα\alpha emission, which provides evidence that the PAHs are well mixed in the ionized superwind gas and outflowing from the disk.Comment: 12 pages, 8 figures, accepted for publication in A&

    Synthesis of infinite-layer LaNiO2 films by metal-organic deposition

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    We report the synthesis of infinite-layer LaNiO2 thin films by metal organic decomposition. Our work is aimed to synthesize perovskite-like oxides with 3d9 electronic configuration, which is common to high-Tc copper oxides. The 3d9 configuration is very rare in oxides other than cuprates. Ni1+ oxides, even though Ni1+ is an unusual oxidation state, may be one of very few candidates. One example of the Ni1+ phases is infinite-layer LaNiO2. The bulk synthesis of LaNiO2 is difficult, but we demonstrate in this article that the thin-film synthesis of LaNiO2 by metal organic decomposition is rather easy. This is due to the advantage of thin films with a large-surface-to-volume ratio, which makes oxygen diffusion prompt. Resistivity measurements indicate that LaNiO2 is essentially a metal but unfortunately with no trace of superconductivity yet.Comment: 13 pages, 4 figure

    Higher Resonance Contributions to the Adler-Weisberger Sum Rule in the Large N_c Limit

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    We determine the NcN_c--dependence of the resonance contributions to the Adler--Weisberger sum rule for the inverse square 1/gA21/g_A^2 of the axial charge coupling constant and show that in the large NcN_c limit the contributions of the Roper-like excitations scale as O(1/Nc)O(1/N_c). Consistency with the 1/Nc21/N_c^2 scaling of the 1/gA21/g_A^2 term in the sum rule requires these contributions to cancel against each other.Comment: 10 pages, LaTeX, TH Darmstadt preprint IKDA 93/47, REVISE

    Fractional electric charge of a magnetic vortex at nonzero temperature

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    An ideal gas of twodimensional Dirac fermions in the background of a pointlike magnetic vortex with arbitrary flux is considered. We find that this system acquires fractional electric charge at finite temperatures and determine the functional dependence of the thermal average and quadratic fluctuation of the charge on the temperature, the vortex flux, and the continuous parameter of the boundary condition at the location of the vortex.Comment: 25 pages, 5 figures, journal version, minor changes, Eqs.(3.2)-(3.5) correcte

    Reconstructing the whole mitochondrial DNA (mtDNA) from nuclear genome.

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    In several eukaryotic organisms, the nuclear genome has several partial copies of the mitochondrial DNA (mtDNA). These copies are called NUMTs (NUclear MiTochondrial DNA) and they have been known since 1967 when the first evidence of them were reported in the mouse nuclear genome. Despite almost fifty years have passed, the reason of their very existence remains controversial. However, their presence has been confirmed in an increasing number of genomes. The NUMts could be only another DNA idiosyncrasy, but they actually represent a serious issue for important application such as genome bar coding. There are many open questions about them.X-meeting 2015

    Dilepton and Photon Emission Rates from a Hadronic Gas III

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    We extend our early analyses of the dilepton and photon emission rates from a hadronic gas to account for strange mesons using a density expansion. The emission rates are reduced to vacuum correlation functions using three-flavor chiral reduction formulas, and the latters are assessed in terms of empirical data. Using a fire-ball, we compare our results to the low and intermediate mass dilepton data available from CERN. Our results suggest that a baryon free hadronic gas does not account for the excess of low mass dielectrons observed at CERES but do well in accounting for the intermediate dimuons at HELIOS. The same observations apply to the recent low and high ptp_t dielectron rates from CERES.Comment: 12 pages LaTeX, 11 eps figure
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