1,720,976 research outputs found
An irresolute linker: separation, and structural and spectroscopic characterization of the two linkage isomers of a Ru(ii)-(2-(2′-pyridyl)pyrimidine-4-carboxylic acid) complex
No full textFor the fi rst time the two linkage isomers of a Ru( II ) complex with 2-(2 ’ -pyridyl)pyrimidine-4-carboxylic acid (cppH) – that form in comparable amounts – have been fully characterized individually. The X-ray structure of each isomer is related to its NMR spectrum in solution
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
The natural borate colemanite at non-ambient conditions: behavior at low temperature and high pressure
No full textColemanite, CaB3O4(OH)3*H2O, is a common mineral in borate sedimentary deposits in saline lakes, related to hydrothermal volcanic activity, and it is one of the main mineral commodities for the extraction of boron. Due to its relative abundance, in particular at the mine dumps, several recent works were devoted to explore its potential technological and industrial applications (see e.g. [1] for a list of references). Despite this interest, very few was known on the behavior of the colemanite crystal structure at non-ambient conditions of temperature and pressure. This contribution reports the results obtained from in situ low-temperature (T < 293 K) and high-pressure experiments.
A displacive phase transition from the centrosymmetric P21/a colemanite to a ferroelectric polymorph with P21 symmetry was long time known to occur in the T-range between 273 and and 263 K (e.g. [2]). Thermal analysis and in situ single-crystal X-ray diffraction data confirmed the transition, which was found to occur between 265 and 260 K. A thorough chemical analysis, performed by a combination of techniques, revealed the relative pureness of the natural sample of colemanite investigated, supporting the hypothesis that the absence of impurities reduces the T of transition to the ferroelectric state (i.e. it reduces the stability field of the ferroelectric polymoprh) [3]. Single crystal X-ray and neutron diffraction data (down to 104 and 20 K, respectively) showed that the transition has limited effects on the crystal structure of colemanite.
On the other hand, in situ high-pressure single-crystal X-ray diffraction experiments disclosed a much more complex scenario, with a first-order reconstructive phase transition occurring between 13.95 and 14.91 GPa, toward a denser polymorph with a = 3*aCOL, b = bCOL and c = 2*cCOL. Despite reconstructive, the transition is single crystal-to-single crystal and involves an increase in the average coordination number of both the Ca and B sites. The tripling of the a-axis and the doubling of the c-axis imply the split of every independent atomic site of colemanite in six new independent positions in the high-P polymorph. In particular, three of the six new sites, generated from the parent triangularly coordinated B, increase their coordination number from three to four, gaining a bond with a H2O oxygen. The elastic behavior of colemanite and of the high-P polymorph have been described by means of III- and II-order Birch-Murnaghan equations of state, respectively, yielding the following bulk moduli: 67(4) GPa (colemanite, KV' = 5.5(7)) and 50(8) GPa (high-P colemanite).
[1] P. Lotti, G.D. Gatta, D. Comboni, G. Guastella, M. Merlini, A. Guastoni, H-P. Liermann J. Am. Cer. Soc. 2017, in press, DOI: 10.1111/jace.14730.
[2] F.N. Hainsworth, H.E. Petch Can. J. Phys. 1966, 44, 3083.
[3] H.H. Wieder, A.R. Clawson, C.R. Perkerson J. Appl. Phys. 1962, 33, 1720
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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