1,721,215 research outputs found
Code Selection Method for Downlink MC-CDMA Over Frequency-Selective Fading Channel
No full text[[abstract]]A spreading code-allocation procedure using simple least squares (LS) channel estimation is presented to reduce multiple-access interference (MAI) in downlink multicarrier code-division multiple-access (MC-CDMA) systems. The spreading codes chosen by the proposed method are in a consistent sequence.[[note]]SC
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Inhibition of HIV-1 Ribonuclease H activity by novel frangula-emodine derivatives
No full textThe HIV-1 reverse transcriptase (RT) associated ribonuclease H (RNase H) activity hydrolyzes the RNA component of the viral heteroduplex RNA:DNA replication intermediate. Even though this function is essential for viral replication, until now only very few compounds have been reported to inhibit it. Anthraquinones are common secondary metabolites which have diverse biological activities. In particular, some of them have been reported to inhibit the HIV-1 RT polymerase and integrase activities in biochemical assays. Given the structural similarities between integrase and RNase H proteins, we synthesized a series of frangula-emodine derivatives and showed that the introduction of a bromine atom in position 7 of the anthraquinone structure leads to derivatives which are able to inhibit both HIV-1 polymerase and RNase H functions at micromolar concentrations. Mechanism of action studies performed on the 7-brom-6-O-phenacyl-1,8-dihydroxy-3-methyl anthraquinone (K67) showed that this compound is a non-competitive inhibitor of the RNase H function and that it binds to a site which is not overlapping to the non-nucleoside RT inhibitors binding site. This study demonstrates that anthraquinone derivatives may be a scaffold to be further developed to obtain selective HIV-1 RNase H inhibitors and represent a new step toward the identification of new anti-RT agents
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Effects of interfacial layers in InGaN/GaN quantum-well structures on their optical and nanostructural properties
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Solving structure in the CP29 light harvesting complex with polarization-phased 2D electronic spectroscopy.
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