1,720,971 research outputs found
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
Backward synthesis of rhenium(I)γ-hydroxyvinylidene and γ-methoxy-vinylidene complexes and their conversion to the allenylidene [Re=C=C=CPh2(CO)2(MeC(CH2Ph2)3](OSO2CF3).
No full textThe reactivity of the rhenium() allenylidene complex [Re{C C CPh2}(CO)2(triphos)](OTf ) (1) [triphos =
MeC(CH2PPh2)3] towards ionic nucleophiles and electrophiles has been explored. Nucleophiles regioselectively attack
the Cγ carbon atom leading to the formation of σ-alkynyl complexes, while electrophiles attack the Cβ atom yielding
carbyne complexes. The sequential addition of OH and H to 1 at low temperature gave the γ-hydroxyvinylidene
complex [Re{CC(H)C(OH)Ph2}(CO)2(triphos)](OTf ) which regenerated 1 above 40 C via H2O elimination
Substitution of labile triflate in [(triphos)Re(CO)(2)(OTf)]: a new synthetic route to mononuclear and dinuclear Re(I) complexes
No full textNew synthetic routes to the neutral complex [(triphos)Re(CO)2(OTf)] [triphos=MeC(CH2PPh2)3, OTf=CF3SO3-] (3) are reported. The triflate ligand in 3 is labile and can be easily replaced by different halides and pseudohalides (CN-, N3-, SCN-, SeCN-, OCN-) to give new mononuclear octahedral ReI complexes of formula [(triphos)Re(CO)2(X)] (X=Cl-, Br-, I-, CN-, N3-, SCN-, SeCN-, OCN-). In some cases, when a double proportion of 3 is treated with the appropriate pseudohalide, rare examples of binuclear ReI complexes featuring a single bridging pseudohalide ligand, [{(triphos)Re(CO)2}2(μ-X)]Y (X=CN-, N3-, SCN-, SeCN-; Y=OTf, BPh4-), have been obtained. All of the new ReI complexes have been characterized by conventional spectroscopic methods and by electrochemical and spectroelectrochemical techniques. Selected examples of regioselective electrophilic alkylations of both halide and pseudohalide ligands are also reported. Noticeably, selective methylation of [(triphos)Re(CO)2(η1-X-XCN)] (X=S, Se) affords the complexes [(triphos)Re(CO)2{η1-X-X(Me)(CN)}]OTf, which contain the unprecedented methylsulfocyanate and methylselenocyanate ligands
Design and formulation of Eudragit-coated zein/pectin nanoparticles for the colon delivery of resveratrol
No full textResveratrol (RSV) is a naturally occurring polyphenolic phytoalexin with beneficial effects on human health, including the treatment and prevention of ulcerative colitis and cancer. This work proposes the formulation and characterization of new nanoparticles (NPs) for the specific colon delivery of RSV. RSV was encapsulated in zein (Z) NPs, coated by a hydrophilic pectin (P) shell to significantly increase the dissolution rate of RSV in aqueous environments. Since the dissolved drug was strongly degraded in a simulated gastrointestinal tract, the ZP-NPs were coated with Eudragit S 100. The coated particles, even if aggregated, had a spherical morphology with diameters in the 100–200 nm range. Release studies of RSV from the ZP coated NPs evidenced their potential ability to induce a specific colon delivery of this drug so that this formulation can be proposed to enrich natural food products to enhance their preventive and therapeutic effects in the lower GI tract
Highly efficient micro-scale liquid-liquid in-flow extraction of99mtc from molybdenum
No full textThe trend to achieve even more compact-sized systems is leading to the development of micro-scale reactors (lab-on-chip) in the field of radiochemical separation and radiopharmaceutical production. Technetium-99m extraction from both high and low specific activity molybdenum could be simply performed by MEK-driven solvent extraction if it were not for unpractical automation. The aim of this work is to develop a solvent extraction and separation process of technetium from molybdenum in a micro-scale in-flow chemistry regime with the aid of a capillary loop and a membrane-based separator, respectively. The developed system is able to extract and separate quantitatively and selectively (91.0 ± 1.8% decay corrected) the [99mTc]TcO4Na in about 20 min, by using a ZAIPUT separator device. In conclusion, we demonstrated for the first time in our knowledge the high efficiency of a MEK-based solvent extraction process of99mTc from a molybdenum-based liquid phased in an in-flow micro-scale regime
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
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