1,720,991 research outputs found
Solvent-free synthesis and key intermediate isolation in Ni2Dy2 catalyst development in the domino ring-opening electrocyclization reaction of furfural and amines
No full textA solvent-free methodology that yields trans-4,5-diaminocyclopent-2-enones, main domains of natural products and variety of N-heterocycles, is described. The bimetallic catalyst [NiII2DyIII2L4(DMF)6] 2(OTf) 2(DMF) (1) promotes the domino reaction of furfural and amines, with loadings as low as 0.01%, under stirring or microwave assisted conditions to afford the corresponding frameworks in very good to excellent yields. Crystallographic and theoretical studies shed light on the exclusive formation of the trans-diastereoisomers via a 4π-conrotatory electrocyclization process elucidating the key step in the catalytic process
Four new families of polynuclear Zn-Ln coordination clusters. Synthetic, topological, magnetic and luminescent aspects
Full text linkThe employment of three structurally related Schiff bases H2L1, H2L2 , and H3L3 with zinc and lanthanide salts under various reaction conditions, gave four families of compounds formulated as [ZnII2LnIII2(L1)4(EtOH)6][ClO4]2 (1-3), [ZnII5Ln(OH)(L1)6(H2O)] (4-6), [(ZnII4LnIII2(OH)2(L2)4(OAc)2(NO3)2(DMF)3]) (7-9), [ZnII2LnIII2(L3)2(NO3)2(CO3)2(CH3OH)2] (10-12) with robust and novel topologies. Synthetic aspects are discussed. A comprehensive topological analysis of all reported ZnII/LnIII CCs with a core nuclearity of four and above is presented and identifies that families (4-6) and (7-9) are the first examples of the 2,3,4M6-1 motif in ZnII/LnIII chemistry. Magnetic studies are presented for the DyIII analogues (1, 7 and 10) are presented, 7 demonstrates field-induced slow relaxation of the magnetization. Fluorescence studies are also discussed
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
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
Chiral Co<sub>3</sub>Y Propeller-Shaped Chemosensory Platforms Based on <sup>19</sup>F‑NMR
No full textTwo propeller-shaped
chiral CoIII3YIII complexes built
from fluorinated ligands are synthesized and characterized
by single-crystal X-ray diffraction (SXRD), IR, UV–vis, circular
dichroism (CD), elemental analysis, thermogravimetric analysis (TGA),
electron spray ionization mass spectroscopy (ESI-MS), and NMR (1H, 13C, and 19F). This work explores
the sensing and discrimination abilities of these complexes, thus
providing an innovative sensing method using a 19F NMR
chemosensory system and opening new directions in 3d/4f chemistry.
Control experiments and theoretical studies shed light on the sensing
mechanism, while the scope and limitations of this method are discussed
and presented
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