1,720,987 research outputs found
Conformational distribution functions extracted from residual dipolar couplings: A hybrid model based on maximum entropy and molecular field theory
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Refined Structures of OPhospholserine and Its Calcium Salt by New Multinuclear Solid-State NMR Crystallography Methods
No full textO-phospho-l-serine (Pser) and its Ca
salt, Ca[O-phospho-l-serine]·H2O (CaPser), play important roles for bone mineralization and
were recently also proposed to account for the markedly improved bone-adhesive
properties of Pser-doped calcium phosphate-based cements for biomedical
implants. However, the hitherto few proposed structural models of
Pser and CaPser were obtained by X-ray diffraction, thereby leaving
the proton positions poorly defined. Herein, we refine the Pser and
CaPser structures by density functional theory (DFT) calculations
and contrast them with direct interatomic-distance constraints from
two-dimensional (2D) nuclear magnetic resonance (NMR) correlation
experimentation at fast magic-angle spinning (MAS), encompassing double-quantum–single-quantum
(2Q–1Q) 1H NMR along with heteronuclear 13C{1H} and 31P{1H} correlation NMR
experiments. The Pser and CaPser structures before and after refinements
by DFT were validated against sets of NMR-derived effective 1H–1H, 1H–31P, and 1H–13C distances, which confirmed the improved
accuracy of the refined structures. Each distance set was derived
from one sole 2D NMR experiment applied to a powder without isotopic
enrichment. The distances were extracted without invoking numerical
spin-dynamics simulations or approximate phenomenological models.
We highlight the advantages and limitations of the new distance-extraction
procedure. Isotropic 1H, 13C, and 31P chemical shifts obtained by DFT calculations using the gauge including
projector augmented wave (GIPAW) method agreed very well with the
experimental results. We discuss the isotropic and anisotropic 13C and 31P chemical-shift parameters in relation
to the previous literature, where most data on CaPser are reported
herein for the first time
Variations on the Author
Get PDF“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
Direct Experimental Evidence for Abundant BO<sub>4</sub>–BO<sub>4</sub> Motifs in Borosilicate Glasses From Double-Quantum <sup>11</sup>B NMR Spectroscopy
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using double-quantum–single-quantum correlation 11B nuclear magnetic resonance (NMR) experiments and atomistic
molecular dynamics (MD) simulations, we resolve the long-standing
controversy of whether directly interlinked BO4–BO4 groups exist in the technologically ubiquitous class of alkali/alkaline-earth
based borosilicate (BS) glasses. Most structural models of Na2O–B2O3–SiO2 glasses assume the absence of B[4]–O–B[4] linkages, whereas they have been suggested to exist in
Ca-bearing BS analogs. Our results demonstrate that while B[4]–O–B[4] linkages are disfavored relative
to their B[3]–O–B[3]/B[4] counterparts, they are nevertheless abundant motifs in Na2O–B2O3–SiO2 glasses
over a large composition space, while the B[4]–O–B[4] contents are indeed elevated in Na2O–CaO–B2O3–SiO2 glasses. We discuss the
compositional and structural parameters that control the degree of
B[4]–O–B[4] bonding
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe 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
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