353 research outputs found

    Dependence of field-aligned electron precipitation on season, altitude and pitch angle

    Get PDF
    The occurrence of field-aligned 2.3 keV electron precipitation was examined by using data from more than 7500 orbits of the polar-orbiting satellite, OGO-4. The frequency of occurrence of field aligned precipitation was highest at actual pitch angles between 7 and 10 deg, being highest in the winter months, at highest satellite altitudes. Acceleration by a localized parallel electric field established by electrostatic charge layers is proposed to explain particle observations

    Positronium reflection and positronium beams

    Get PDF
    Specular reflection of positronium, Ps was observed and that there is adequate intensity at higher energies to make further study worthwhile was established. The scattering appears to be restricted to the outermost surface with a mean free path of (0.75 + or - 0.15)A for Ps in LiF(100). With a greater intensity Ps beam one should see higher order diffraction beams as the result of the periodicity of the surface. Ps diffraction thus offers the possibility of being a novel and valuable probe to study the outermost surface and to study adsorbants on it. Two methods for producing Ps beams are described

    Molybdenum Complexes of Chiral C2-symmetric Picchxn-type Ligands: Synthesis, Characterization, and Structural Studies

    Get PDF
    A series of molybdenum complexes based on chiral C2-symmetric picchxn-type ligands (N4 ligands, defined as trans-N,Nâ€Č-bis(heterocycl-2-ylmethyl)-1,2-diaminocyclohexanes) has been synthesized and characterized. Reported and novel picchxn-type ligands form (Îș3-N4)Mo(CO)3, [(Îș4-N4)Mo(NO)(CO)]PF6, and [(Îș4-N4)Mo(NO)X]PF6 (X = Br, I) compounds. Multiple tridentate (Îș3) and tetradentate (Îș4) ligand configurations were observed, and the favored Îș4 configuration was found to vary with N4 heterocycle identity. Heterocycle variation allowed for directed modification of the molybdenum electronic characteristics, but none of the studied {(Îș4-N4)Mo(NO)}+ fragments was found to be a suitable π-base for dearomatization chemistry. The crystal structures of eight molybdenum complexes with picchxn-type ligands were determined

    Detecting, Quantifying, and Discriminating the Mechanism of Mosaic Chromosomal Aneuploidies Using MAD-seq

    Get PDF
    Current approaches to detect and characterize mosaic chromosomal aneuploidy are limited by sensitivity, efficiency, cost, or the need to culture cells. We describe the mosaic aneuploidy detection by massively parallel sequencing (MAD-seq) capture assay and the MADSEQ analytical approach that allow low

    Full potential LAPW calculation of electron momentum density and related properties of Li

    Full text link
    Electron momentum density and Compton profiles in Lithium along ,, , and directions are calculated using Full-Potential Linear Augmented Plane Wave basis within generalized gradient approximation. The profiles have been corrected for correlations with Lam-Platzman formulation using self-consistent charge density. The first and second derivatives of Compton profiles are studied to investigate the Fermi surface breaks. Decent agreement is observed between recent experimental and our calculated values. Our values for the derivatives are found to be in better agreement with experiments than earlier theoretical results. Two-photon momentum density and one- and two-dimensional angular correlation of positron annihilation radiation are also calculated within the same formalism and including the electron-positron enhancement factor.Comment: 11 pages, 7 figures TO appear in Physical Review

    Contexting Koreans: Does the High/Low Model Work?

    Full text link
    South Korea is assumed to be a high-context culture with extensive shared information and an emphasis on relationships in doing business. The follow ing study reported here tests this assumption and illustrates similarities and differences between Korean and American writers in an attempt to document language differences between high- and low- context societies. Data in the texts studied did not confirm the high/low contextfeatures expected. South Korean texts showed more similarities to than differences from the American texts, and the language features found suggest a more complex context situa tion than the high/low context model may be able to accommodate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66563/2/10.1177_108056999806100403.pd

    Towards an understanding of hole superconductivity

    Full text link
    From the very beginning K. Alex M\"uller emphasized that the materials he and George Bednorz discovered in 1986 were holehole superconductors. Here I would like to share with him and others what I believe to be thethe key reason for why high TcT_c cuprates as well as all other superconductors are hole superconductors, which I only came to understand a few months ago. This paper is dedicated to Alex M\"uller on the occasion of his 90th birthday.Comment: Dedicated to Alex M\"uller on the Occasion of his 90th Birthday. arXiv admin note: text overlap with arXiv:1703.0977

    Genetic influences in different aspects of language development: The etiology of language skills in 4.5 year-old twins

    Get PDF
    The genetic and environmental etiologies of diverse aspects of language ability and disability, including articulation, phonology, grammar, vocabulary, and verbal memory, were investigated in a U.K. sample of 787 pairs of 4.5-year-old same-sex and opposite-sex twins. Moderate genetic influence was found for all aspects of language in the normal range. A similar pattern was found at the low end of the distribution with the exception of two receptive measures. Environmental influence was mainly due to nonshared factors, unique to the individual, with little influence from shared environment for most measures. Genetic and environmental influences on language ability and disability are quantitatively and qualitatively similar for males and females
    • 

    corecore