1,721,028 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Tunable band gap and magnetism in C 2x-(BN) y sheets and ribbons

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    We predict using first-principles calculations that recently synthesized C-BN nanostructures exhibit rich magnetic and electronic properties that are sensitive to system dimensionality and chirality. Due to different C-B(N) p<sub>z</sub>-orbital hybridization at the interface, two-dimensional zigzag C-BN sheets and one-dimensional zigzag nanoribbons show weak and strong magnetism respectively. Moreover, the band gap of the zigzag ribbons shows strong sensitivity to the edge magnetism and the BN concentration. For armchair systems, the band gap of the C-BN sheets and ribbons exhibits distinct variation trends with the changing BN concentration, correlating with the width of the adjacent graphene nanoribbon

    Nanoscale multilayer transition-metal dichalcogenide heterostructures: Band gap modulation by interfacial strain and spontaneous polarization

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    Using density functional theory calculations, we unveil intriguing electronic properties of nanoscale multilayer transition-metal dichalcogenide (TMDC) heterostructures, (MoX<sub>2</sub>)<sub><i>n</i></sub>(MoY<sub>2</sub>)<sub><i>m</i></sub> (X, Y = S, Se or Te). Our results show that the structural stability and electronic band structure of the TMDC heterostructures depend sensitively on the choice of constituent components and their relative thickness. In particular, the electronic band gap can be tuned over a wide range by the intrinsic mismatch strain and spontaneous electrical polarization at the interface of the heterostructures, which suggests desirable design strategies for TMDC-based devices with an easily adjustable band gap. These interfacial effects also make the electronic properties more susceptible to the influence of a bias electric field, which can induce sensitive and considerable changes in the band gap and even produce a semiconductor–metal transition at relatively low electric fields. Such effective electronic band gap engineering via a combination of internal (i.e., the composition and layer thickness) and external (i.e., a bias field) control makes the TMDC-based heterostructures promising candidates for applications in a variety of nanodevices

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis

    Dispelling the Myths Behind First-author Citation Counts

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    We conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more sophisticated methods

    Author Index

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    koamabayili/VECTRON-author-checklist: VECTRON author checklist

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    We have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used

    Emergent properties and trends of a new class of carbon nanocomposites: Graphene nanoribbons encapsulated in a carbon nanotube

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    Using density functional theory calculations, we show that recently synthesized carbon nanocomposites of graphene nanoribbons encapsulated in a carbon nanotube (GNR@CNT) possess rich emergent electronic and magnetic properties that offer new functionality and tunability and display systematic trends that are sensitive to the matchup of constitutive GNRs and CNTs. The encapsulation of H-passivated GNRs in metallic armchair CNTs always leads to a metallic complex while those in semiconducting zigzag CNTs can be either metallic or semiconducting depending on the chirality of GNRs. In particular, the complex of armchair GNRs in a zigzag CNT exhibits an oscillating electronic band gap with changing GNR width and a well-separated spatial distribution of electrons and holes localized in the CNT and GNR components, respectively. When bare large zigzag GNRs are encapsulated in an armchair CNT, the resulting complex shows strong structural stability and enhanced magnetism and, most interestingly, such GNR@CNT configurations can be tuned to be metallic or semiconducting depending on relative bond position and magnetic order. These results offer key insights for understanding and predicting emergent properties of GNR@CNT, which establish a roadmap for guiding design and synthesis of specific nanocomposite configurations with tailor-made properties for nanoelectronic, photovoltaic and spintronic applications
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