1,720,956 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
P-induced crystal-fluid interaction in 6-membered ring zeolites: the case of ERI, OFF and EAB topologies
No full textPressure (P)-induced intrusion of molecules (or solvated ions) into the structural nano-cavities of microporous materials opened a new route to promote a mass transfer from fluids to structurally-incorporated molecules. A full understanding of this phenomenon in natural or synthetic zeolites might expand the number of their utilizations, e.g. tailoring of new materials, as catalysts in industrial processes [1,2]. On the other hand, from the geological point of view, the study of this phenomenon is unveiling the role played by zeolites as fluid carriers in the upper Earth crust, e.g. during the early subduction of oceanic sediments or altered basalts.
We have investigated the high-P behaviour, promoting P-mediated crystal-fluid interaction, of three different zeolites with structural homologies: erionite (ERI framework type, 6-membered ring sequence: AABAAC), offretite (OFF, with AAB seq.), bellbergite (EAB, with AABCCB seq.) and its synthetic counterpart. These studies allowed to 1) a better understanding of the potential role played by erionite as fluid carrier during the early subduction, being this mineral a constituent of ocean floors basaltic alteration [3] and 2) compare the mechanisms adopted by structurally similar 6-mRs frameworks to accommodate the bulk compression and the crystal-fluid interactions.
Synchrotron X-ray diffraction experiments have been performed on natural single crystals of erionite, bellbergite and offretite. Additionally, experiments have been performed on powder samples with EAB framework (synthetized according to the Aiello-Barrer protocol [4] and treated in order to obtain Na- and K- forms). Both non penetrating (silicone oil and daphne oil 7575) and potentially penetrating P-transmitting fluids (methanol:ethanol:water 16:3:1 mixture, ethanol:water 1:1 mixture, methanol, H2O, liquid Ne) have been used.
Among the natural samples, erionite resulted to be the one with the highest magnitude of adsorption. The new adsorbed molecules act as “pillars” within the framework nanocavities, decreasing the compressibility of the structure. Moreover, the magnitude of the intrusion resulted to be strictly related to the H2O content of the hydrous P-transmitting fluids.
Ne atoms were able to penetrate into the 12mRs channel of the offretite framework in response to the applied pressure, with weak Van der Waals interactions with the extra-framework population. Methanol resulted to behave as a non-penetrating fluid for natural bellbergite, while it acts as a penetrating fluid in the synthetic counterparts. This highlighted the role of “secondary factors” on the occurrence of crystal-fluid interaction, e.g. the extra-framework content of the sample and the size of crystallites (single crystal of natural bellbergite vs. synthetic EAB powder).
References
[1] G.D. Gatta, P. Lotti, G. Tabacchi, (2018), The effect of pressure on open‐framework silicates: elastic behaviour and crystal–fluid interaction, Phys. Chem. Miner., 45, 115–138
[2] D. Comboni, F. Pagliaro, P. Lotti, G.D. Gatta, M. Merlini, S. Milani, M. Migliori, G. Giordano, E. Catizzone, I.E. Collings, M. Hanfland, (2020), The elastic behavior of zeolitic frameworks: The case of MFI type zeolite under high-pressure methanol intrusion, Catal. Today, 345, 88–96.
[3] F. Vitali, G. Blanc, P. Larqué, (1995), Zeolite distribution in volcaniclastic deep-sea sediments from the Tonga Trench Margin (SW Pacific), Clays and Clay Miner., 43, 92–104.
[4] R.Aiello, R.M. Barrer, (1970), Hydrothermal Chemistry of Silicates
Pressure-mediated adsorption in 6-membered ring zeolites with EAB topology
Full text linkThe intrusion of molecules or solvated ions into the nano-cavities of microporous materials, such as zeolites, through P-induced intrusion, has opened new opportunities for promoting mass transfer from fluids to molecules incorporated in framework structure. Understanding this phenomenon in natural or synthetic zeolites could expand their utilization, tailor new functional materials or improving catalytic abilities in industrial processes. In this study, we synthesized EAB samples using the Aiello-Barrer protocol (Aiello and Barrer 1970) and treated them to obtain the Na- and K-form. The high-pressure behaviour of the Na- and K- EAB zeolites has been then investigated using in-situ single-crystal and powder synchrotron X-ray diffraction, with a diamond anvil cell, at the ID15B beamline of ESRF in Grenoble, France. Additionally, high-pressure experiments were performed also on bellbergite (ideally (K,Ba,Sr)2Sr2Ca2(Ca,Na)4[Al3Si3O12]6·30H2O), the natural analogue of EAB zeolite. Distilled water, methanol, and the non-penetrating silicone oil were used as hydrostatic pressure-transmitting fluids. The results of this research allowed to understand the role played by the pre-existing extra-framework population in the adsorption of penetrating pressure fluids, and lead to a qualitative assessment of the fluid adsorption, by comparing the compressibility of these microporous crystal structures compressed in different P-transmitting media. Additionally, relevant high-pressure deformation mechanisms were described
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
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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