1,723,143 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
Recommended from our members
Die Glasbildung im System Li₂O-SiO₂
Full text linkDer Bereich der Glasbildung im System Li₂O-SiO₂ liegt unter konstant gehaltenen Bedingungen (luftabgeschreckte Schmelztropfen) zwischen 27 und 37 Mol-% Li₂O. Schmelzen mit weniger als 27 Mol-% Li₂O und Schmelzen mit mehr als 37 Mol-% Li₂O entglasen. Die Ursache der Trübung der Gläser im kieselsäurereichen Gebiet des Systems Li₂O-SiO₂ ist die Kristallisation von SiO₂ aus der Schmelze. Die Kristalle sind allerdings so klein, dass ein Opalglas entsteht. Das Entglasungsprodukt im lithiumreichen Gebiet des Systems Li₂O-SiO₂ ist Lithium-Metasilikat (Li₂O*SiO₂). In diesem Fall sind die Kristalle größer (dem bloßen Auge sichtbar). Die Kristallisation von SiO₂ aus kieselsäurereichen Schmelzen im System Li₂O-SiO₂ kann durch Zusatz kleiner Mengen von Al₂O₃ oder Ga₂O₃ (1 bzw. 2 Mol-% bei luftabgeschreckten Tropfen) verhindert werden. Es wird angenommen, dass die Opaleszenz (SiO₂-Ausscheidung) im kieselsäurereichen Gebiet des Systems Li₂O-SiO₂ und die umgekehrt "s"-förmigen Liquiduskurve in diesem Gebiet Beweise für eine nichthomogene Struktur der Schmelze sind. Demnach liegen in ihr Bereiche von praktisch reinen SiO₂ mit einer wohlgeordneten Struktur vor, und diese sind die Keimbildungszentren des Cristobalits
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
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
Enhancing the oxidation of Li₂O₂ in Li-O₂ batteries : mechanistic and chemical efficacy probing
No full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.Includes bibliographical references (pages 161-175).The wide consensus regarding anthropogenic climate change, the positive correlation between economic growth and greenhouse gas emissions, and the humanitarian need for further global growth urges the decoupling of energy usage and emissions. To power portable electronics, enable electrification of transport, level the load on the current fossil-fuel powered grid, and provide storage for clean but intermittent wind and solar, low-cost and high energy density battery chemistries such as lithium-oxygen (Li-O₂) are being vigorously pursued beyond Li-Ion. The present thesis reports on efforts to devise and understand reaction promoters to enhance the kinetics of charging of Li-0₂ cells for the purpose of boosting round-trip efficiency, one of the most severe issues in the system. Investigating trends in electrochemical current output during charge in electrodes containing transition metal nanoparticles and metal oxides, we revealed a strong correlation between the conversion enthalpy of the promoter with Li₂O₂ towards formation of a corresponding lithium-rich metal oxide. Experimental evidence of formation of Li₂CrO₄, and Li₂MoO₄ is provided. Ru nanoparticles showed the formation of a surface phase in contact with Li₂O₂ which is assigned to Li₂RuO₃. We postulate solid-state promoters activate the oxidation of Li₂O₂ by enabling the formation of a lithium-rich metal oxide intermediate which proceeds to delithiate with enhanced kinetics compared to the direct decomposition of Li₂O₂. A microkinetics analysis successfully explains the excellent Li₂O₂ oxidation activity of metal nanoparticles such as Cr, Mo, and Ru as well as the relative inactivity at 3.9 VU of Mn, Co and other derivative oxides. Using differential electrochemical mass spectrometry (DEMS), the same conversion mechanism appears to result in sub-stoichiometric evolution of oxygen on charging as conversion enthalpy increase. In the second and last part of this thesis, cobalt bis(terpyridine) metal complex (Co(Terp)2) is demonstrated as redox mediator of the electron transfer to the insulating Li₂O₂. However, chemical probing using DEMS revealed a parasitic Co II to Co l reduction during discharge using the metal complex while the ideal 2.0 e-/O₂ formation of Li₂O₂ is observed with benchmark mediator tetrathiafulvalene. On charge substoichiometric O₂ regeneration is observed for both mediators; however, improved oxygen regeneration is seen using TTF.by Koffi Pierre Claver Yao.Ph. D
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
Reversibility of Noble Metal-Catalyzed Aprotic Li-O-2 Batteries
No full textThe aprotic Li-O-2 battery has attracted a great deal of interest because, theoretically, it can store far more energy than today's batteries. Toward unlocking the energy capabilities of this neotype energy storage system, noble metal-catalyzed high surface area carbon materials have been widely used as the 02 cathodes, and some of them exhibit excellent electrochemical performances in terms of round-trip efficiency and cycle life. However, whether these outstanding electrochemical performances are backed by the reversible formation/ decomposition of Li2O2, i.e., the desired Li-O-2 electrochemistry, remains unclear due to a lack of quantitative assays for the Li-O-2 cells. Here, noble metal (Ru and Pd)-catalyzed carbon nanotube (CNT) fabrics, prepared by magnetron sputtering, have been used as the O-2 cathode in aprotic Li-O-2 batteries. The catalyzed Li-O-2 cells exhibited considerably high round-trip efficiency and prolonged cycle life, which could match or even surpass some of the best literature results. However, a combined analysis using differential electrochemical mass spectrometry and Fourier transform infrared spectroscopy, revealed that these catalyzed Li-O-2 cells (particularly those based on Pd-CNT cathodes) did not work according to the desired Li-O-2 electrochemistry. Instead the presence of noble metal catalysts impaired the cells' reversibility, as evidenced by the decreased O-2 recovery efficiency (the ratio of the amount of O-2 evolved during recharge/that consumed in the preceding discharge) coupled with increased CO2 evolution during charging. The results reported here provide new insights into the O-2 electrochemistry in the aprotic Li-O-2 batteries containing noble metal catalysts and exemplified the importance of the quantitative assays for the Li-O-2 reactions in the course of pursuing truly rechargeable Li-O-2 batteries
- …
