1,720,960 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
Fe3+ distribution and Fe3+/sigma Fe-Oxygen fugacity variations in Kimberlite-Borne Eclogite Xenoliths, with comments on Clinopyroxene-Garnet Oxy-thermobarometry
No full textThe valence state of iron in mantle-derived melts, such as mid-ocean ridge basalt, is a useful proxy for oxygen fugacity (integral O-2). On subduction, oceanic crust undergoes metamorphic reactions that alter its initial integral O-2, generating compositional and redox heterogeneity in the supra-subduction zone and in the convecting mantle source of oceanic basalts. Kimberlite-borne eclogite xenoliths with ancient oceanic crustal protoliths represent an important archive to trace these processes in deep time. We determined, by Mossbauer spectroscopy, Fe3+/sigma Fe for garnet (0.03-0.15, average 0.08; n = 13) and clinopyroxene (0.05-0.37, average 0.23; n = 11) in bimineralic eclogite xenoliths from the Udachnaya kimberlite pipe (Siberian craton), combined the results with high-quality literature data to estimate bulk Fe3+/sigma Fe and integral O-2, assessed associated uncertainties and discussed petrological implications. The incorporation of Fe3+ in, and distribution between, eclogite minerals is controlled by chemical composition (X), temperature (T), pressure (P) and integral O-2. Therefore, Fe3+/sigma Fe in garnet alone is an imperfect proxy for bulk Fe3+/sigma Fe. Values for the distribution of Fe3+/sigma Fe between clinopyroxene and garnet (D(Fe3+/sigma Fe)(cpx-grt)) range from 1.4 +/- 0.1 to 20 +/- 13 and correlate strongly with the abundance distribution of another polyvalent element, vanadium (r(2) = 0.80, n = 28), probably because both vary as a function of X-T-P-integral O-2. This allows to estimate Fe3+/sigma Fe in clinopyroxene and bulk rocks (0.01-0.32, average 0.06, n = 159) for the majority of literature data where only garnet Fe3+/sigma Fe is known. Low Fe3+/sigma Fe is retained in many high-Al2O3 eclogites with plagioclase-rich cumulate protoliths (Eu/Eu*> > 1), despite extended residence in the cratonic lithosphere. Bulk Fe3+/sigma Fe increases during mantle metasomatism but is not particularly linked to enrichment in highly incompatible elements. Low grossular content in garnet ensuing from mantle metasomatism, especially at low temperature, limits uptake of Fe3+, which is accommodated in clinopyroxene instead, leading to very high D(Fe3+/sigma Fe)(cpx-grt). Eclogite oxybarometry requires that Fe3+/sigma Fe of only garnet be known, whereby the input temperatures should be calculated with all Fe as Fe2+. For temperatures projected onto regional steady-state geothermal gradients, integral O-2 values relative to the fayalite-magnetite-quartz buffer ( increment log integral O-2(FMQ)) range from -5.9 to -0.2 (average - 3.1, n = 174), and are too low to stabilise oxidised sulphur in all and oxidised carbon in the vast majority of samples. Thus, ancient oceanic crust was a sink rather than a source of oxygen. In particular CaO-rich eclogite xenoliths occasionally are corundum-bearing and SiO2-undersaturated, typically with silica-deficient clinopyroxene with cations per formula unit <1.97 for 6 O anions, resulting in overestimated integral O-2.For the remaining samples, cryptic metasomatism, with enrichment in highly incompatible elements, is clearly focused in the integral O-2 interval of FMQ-4 to FMQ-3, indicating that mantle metasomatism can have both an oxidising and a reducing effect on eclogite. Unmetasomatised bimineralic eclogites have lower integral O-2 than coesite-bearing ones, reflecting reduction during metamorphism and silica-consuming partial melting of ancient subducted oceanic crust
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
Iron oxidation state in garnet and clinopyroxene inclusions in E-type diamonds from Udachnaya
No full textDispelling 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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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