1,337 research outputs found

    Examining the Influence of Time-Use Preferences on Technology Acceptance: The Role of Computer Polychronicity

    Get PDF
    Past research recognizes the important influence of individual beliefs on technology acceptance and use. This line of research has also identified a variety of factors that drive the formation of these beliefs. One category of variables that has not received much attention in this research stream consists of individual preferences, in particular time-use preferences. In the current study we add to the literature on technology acceptance, and belief formation in particular, by introducing and empirically testing a new construct labeled computer polychronicity, which captures individuals’ time-use preferences regarding IT. Computer polychronicity is positioned in this study as a key driver of perceived usefulness, mediating the effects of computer anxiety and computer playfulness. Overall, the results support the notion that preferences play important roles in the formation of technology-related beliefs

    Correlation of conductivity and angle integrated valence band photoemission characteristics in single crystal iron perovskites for 300 K < T < 800 K: Comparison of surface and bulk sensitive methods

    Full text link
    A single crystal monolith of La0.9Sr0.1FeO3 and thin pulsed laser deposited film of La0.8Sr0.2Fe0.8Ni0.2O3 were subject to angle integrated valence band photoemission spectroscopy in ultra high vacuum and conductivity experiments in ambient air at temperatures from 300 K to 800 K. Except for several sputtering and annealing cycles, the specimen were not prepared in-situ.. Peculiar changes in the temperature dependent, bulk representative conductivity profile as a result of reversible phase transitions, and irreversible chemical changes are semi-quantitatively reflected by the intensity variation in the more surface representative valence band spectra near the Fermi energy. X-ray photoelectron diffraction images reflect the symmetry as expected from bulk iron perovskites. The correlation of spectral details in the valence band photoemission spectra (VB PES) and details of the conductivity during temperature variation suggest that valuable information on electronic structure and transport properties of complex materials may be obtained without in-situ preparation

    Direct Observation of High-Temperature Polaronic Behavior In Colossal Magnetoresistive Manganites

    Full text link
    The temperature dependence of the electronic and atomic structure of the colossal magnetoresistive oxides La1−xSrxMnO3La_{1-x}Sr_{x}MnO_{3} (x = 0.3, 0.4) has been studied using core and valence level photoemission, x-ray absorption and emission, and extended x-ray absorption fine structure spectroscopy. A dramatic and reversible change of the electronic structure is observed on crossing the Curie temperature, including charge localization and spin moment increase of Mn, together with Jahn-Teller distortions, both signatures of polaron formation. Our data are also consistent with a phase-separation scenario.Comment: 5 pages, 4 figures, revte

    Effect of sintering temperature under high pressure in the uperconductivity for MgB2

    Full text link
    We report the effect of the sintering temperature on the superconductivity of MgB2 pellets prepared under a high pressure of 3 GPa. The superconducting properties of the non-heated MgB2 in this high pressure were poor. However, as the sintering temperature increased, the superconducting properties were vastly enhanced, which was shown by the narrow transition width for the resistivity and the low-field magnetizations. This shows that heat treatment under high pressure is essential to improve superconducting properties. These changes were found to be closely related to changes in the surface morphology observed using scanning electron microscopy.Comment: 3 Pages including 3 figure

    Missed prediction of the neutron halo in 37^{37}Mg

    Full text link
    Halo phenomena have long been an important frontier in both experimental and theoretical nuclear physics. 37^{37}Mg was identified as a halo nucleus in 2014 and remains the heaviest nuclear halo system to date. While the halo phenomenon in 37^{37}Mg was not predicted before the discovery, its description has been still challenging afterwards. In this Letter, we report a microscopic, self-consistent, and density-functional independent description of the neutron halo in 37^{37}Mg by the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) that was developed in 2010. The experimental neutron separation energies and empirical matter radii of neutron-rich magnesium isotopes as well as the deformed pp-wave halo characteristics of 37^{37}Mg are well reproduced without any free parameters. The DRHBc theory investigated only even-even magnesium isotopes in previous works and for that reason missed predicting 37^{37}Mg as a halo nucleus before 2014. Although the core and the halo of 37^{37}Mg are both prolate, higher-order shape decoupling on the hexadecapole and hexacontatetrapole levels is predicted.Comment: 8 pages, 4 figures, 1 tabl

    The Infrared Einstein Ring in the Gravitational Lens MG1131+0456 and the Death of the Dusty Lens Hypothesis

    Get PDF
    We have obtained and modeled new NICMOS images of the lens system MG1131+0456, which show that its lens galaxy is an H=18.6 mag, transparent, early-type galaxy at a redshift of about z_l = 0.85; it has a major axis effective radius R_e=0.68+/-0.05 arcsec, projected axis ratio b/a=0.77+/-0.02, and major axis PA=60+/-2 degrees. The lens is the brightest member of a group of seven galaxies with similar R-I and I-H colors, and the two closest group members produce sufficient tidal perturbations to explain the ring morphology. The host galaxy of the MG1131+0456 source is a z_s > 2 ERO (``extremely red object'') which is lensed into optical and infrared rings of dramatically different morphologies. These differences imply a strongly wavelength-dependent source morphology that could be explained by embedding the host in a larger, dusty disk. At 1.6 micron (H), the ring is spectacularly luminous, with a total observed flux of H=17.4 mag and a de-magnified flux of 19.3 mag, corresponding to a 1-2L_* galaxy at the probable source redshift of z_s > 2. Thus, it is primarily the stellar emission of the radio source host galaxy that produces the overall colors of two of the reddest radio lenses, MG1131+0456 and B~1938+666, aided by the suppression of optical AGN emission by dust in the source galaxy. The dusty lens hypothesis -- that many massive early-type galaxies with 0.2 < z_l < 1.0 have large, uniform dust opacities -- is ruled out.Comment: 27 pages, 8 COLOR figures, submitted to ApJ. Black and white version available at http://cfa-www.harvard.edu/castle

    Role of preferential weak hybridization between the surface-state of a metal and the oxygen atom in the chemical adsorption mechanism

    No full text
    We report on the chemical adsorption mechanism of atomic oxygen on the Pt(111) surface using angle-resolved-photoemission spectroscopy (ARPES) and density functional calculations. The detailed band structure of Pt(111) from ARPES reveals that most of the bands near the Fermi level are surface-states. By comparing band maps of Pt and O/Pt, we identify that dxz (dyz) and dz2 orbitals are strongly correlated in the surface-states around the symmetry point M and K, respectively. Additionally, we demonstrate that the s- or p-orbital of oxygen atoms hybridizes preferentially with the dxz (dyz) orbital near the M symmetry point. This weak hybridization occurs with minimal charge transfer

    Cuticular protein with a low complexity sequence becomes cross-linked during insect cuticle sclerotization and is required for the adult molt

    Get PDF
    Citation: Mun, S., Noh, M. Y., Dittmer, N. T., Muthukrishnan, S., Kramer, K. J., Kanost, M. R., & Arakane, Y. (2015). Cuticular protein with a low complexity sequence becomes cross-linked during insect cuticle sclerotization and is required for the adult molt. Scientific Reports, 5, 11. doi:10.1038/srep10484In the insect cuticle, structural proteins (CPs) and the polysaccharide chitin are the major components. It has been hypothesized that CPs are cross-linked to other CPs and possibly to chitin by quinones or quinone methides produced by the laccase2-mediated oxidation of N-acylcatechols. In this study we investigated functions of TcCP30, the third most abundant CP in protein extracts of elytra (wing covers) from Tribolium castaneum adults. The mature TcCP30 protein has a low complexity and highly polar amino acid sequence. TcCP30 is localized with chitin in horizontal laminae and vertically oriented columnar structures in rigid cuticles, but not in soft and membranous cuticles. Immunoblot analysis revealed that TcCP30 undergoes laccase2-mediated cross-linking during cuticle maturation in vivo, a process confirmed in vitro using recombinant rTcCP30. We identified TcCPR27 and TcCPR18, the two most abundant proteins in the elytra, as putative crosslinking partners of TcCP30. RNAi for the TcCP30 gene had no effect on larval and pupal growth and development. However, during adult eclosion, similar to 70% of the adults were unable to shed their exuvium and died. These results support the hypothesis that TcCP30 plays an integral role as a cross-linked structural protein in the formation of lightweight rigid cuticle of the beetle
    • 

    corecore