7,418 research outputs found

    ArticleRank: a PageRank-based alternative to numbers of citations for analysing citation networks

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    Purpose - The purpose of this paper is to suggest an alternative to the widely used Times Cited criterion for analysing citation networks. The approach involves taking account of the natures of the papers that cite a given paper, so as to differentiate between papers that attract the same number of citations. Design/methodology/approach - ArticleRank is an algorithm that has been derived from Google's PageRank algorithm to measure the influence of journal articles. ArticleRank is applied to two datasets - a citation network based on an early paper on webometrics, and a self-citation network based on the 19 most cited papers in the Journal of Documentation - using citation data taken from the Web of Knowledge database. Findings - ArticleRank values provide a different ranking of a set of papers from that provided by the corresponding Times Cited values, and overcomes the inability of the latter to differentiate between papers with the same numbers of citations. The difference in rankings between Times Cited and ArticleRank is greatest for the most heavily cited articles in a dataset. Originality/value - This is a novel application of the PageRank algorithm

    Summary of Jimsonde temperature profiles. Part 2: Programs, data comments

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    Natural environment criteria are established and interpreted for aeronautical vehicle design and engineering operations. Data summaries, computer formats, frequency distributions, and composite listings of the temperature profiles acquisition program are included

    The role of BST2/tetherin in feline retrovirus infection

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    Pathogenic retroviral infections of mammals have induced the evolution of cellular anti-viral restriction factors and have shaped their biological activities. This intrinsic immunity plays an important role in controlling viral replication and imposes a barrier to viral cross-species transmission. Well-studied examples of such host restriction factors are TRIM5α, an E3 ubiquitin ligase that binds incoming retroviral capsids in the cytoplasm via its C-terminal PRY/SPRY (B30.2) domain and targets them for proteasomal degradation, and APOBEC3 proteins, cytidine deaminases that induce hypermutation and impair viral reverse transcription. Tetherin (BST-2, CD317) is an interferon-inducible transmembrane protein that potently inhibits the release of nascent retrovirus particles in single-cycle replication assays. However, whether the primary biological activity of tetherin in vivo is that of a restriction factor remains uncertain as recent studies on human tetherin suggest that it is unable to prevent spreading infection of human immunodeficiency virus type 1 (HIV-1). The feline tetherin homologue resembles human tetherin in amino acid sequence, protein topology and anti-viral activity. Transiently expressed feline tetherin displays potent inhibition of feline immunodeficiency virus (FIV) and HIV-1 particle release. However, stable ectopic expression of feline tetherin in a range of feline cell lines has no inhibitory effect on the growth of either primary or cell culture-adapted strains of FIV. By comparing and contrasting the activities of the felid and primate tetherins against their respective immunodeficiency-causing lentiviruses we may gain insight into the contribution of tetherins to the control of lentiviral replication and the evolution of lentiviral virulence

    Combination of molecular similarity measures using data fusion

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    Many different measures of structural similarity have been suggested for matching chemical structures, each such measure focusing upon some particular type of molecular characteristic. The multi-faceted nature of biological activity suggests that an appropriate similarity measure should encompass many different types of characteristic, and this article discusses the use of data fusion methods to combine the results of searches based on multiple similarity measures. Experiments with several different types of dataset and activity suggest that data fusion provides a simple, but effective, approach to the combination of individual similarity measures. The best results were generally obtained with a fusion rule that sums the rank positions achieved by each molecule in searches using individual measures

    Theoretical study of even denominator fractions in graphene: Fermi sea versus paired states of composite fermions

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    The physics of the state at even denominator fractional fillings of Landau levels depends on the Coulomb pseudopotentials, and produces, in different GaAs Landau levels, a composite fermion Fermi sea, a stripe phase, or, possibly, a paired composite fermion state. We consider here even denominator fractions in graphene, which has different pseudopotentials as well as a possible four fold degeneracy of each Landau level. We test various composite fermion Fermi sea wave functions (fully polarized, SU(2) singlet, SU(4) singlet) as well as the paired composite fermion states in the n=0 and n=1n=1 Landau levels and predict that (i) the paired states are not favorable, (ii) CF Fermi seas occur in both Landau levels, and (iii) an SU(4) singlet composite fermion Fermi sea is stabilized in the appropriate limit. The results from detailed microscopic calculations are generally consistent with the predictions of the mean field model of composite fermions

    The Growing Importance of Cognitive Skills in Wage Determination

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    Using data from two longitudinal surveys of American high school seniors, we show that basic cognitive skills had a larger impact on wages for 24-year-old men and women in 1986 than in 1978. For women, the increase in the return to cognitive skills between 1978 and 1986 accounts for all of the increase in the wage premium associated with post-secondary education. We also show that high school seniors' mastery of basic cognitive skills had a much smaller impact on wages two years after graduation than on wages six years after graduation.

    Beyond the Fermi Liquid Paradigm: Hidden Fermi Liquids

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    An intense investigation of possible non-Fermi liquid states of matter has been inspired by two of the most intriguing phenomena discovered in the past quarter century, namely high temperature superconductivity and the fractional quantum Hall effect. Despite enormous conceptual strides, these two fields have developed largely along separate paths. Two widely employed theories are the resonating valence bond theory for high temperature superconductivity and the composite fermion theory for the fractional quantum Hall effect. The goal of this "perspective" article is to note that they subscribe to a common underlying paradigm: they both connect these exotic quantum liquids to certain ordinary Fermi liquids residing in unphysical Hilbert spaces. Such a relation yields numerous nontrivial experimental consequences, exposing these theories to rigorous and definitive tests.Comment: perspective articl

    Experimental Demonstration of Fermi Surface Effects at Filling Factor 5/2

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    Using small wavelength surface acoustic waves (SAW) on ultra-high mobility heterostructures, Fermi surface properties are detected at 5/2 filling factor at temperatures higher than those at which the quantum Hall state forms. An enhanced conductivity is observed at 5/2 by employing sub 0.5 micron wavelength SAW, indicating a quasiparticle mean-free-path substantially smaller than that in the lowest Landau level. These findings are consistent with the presence of a filled Fermi sea of composite fermions, which may pair at lower temperatures to form the 5/2 ground state.Comment: 11 pages, 4 figure
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