1,721,018 research outputs found
Transition metals complexed to ordered mesophases. Synthesis, characterization, and mesomorphic properties of new potentially ferroelectric liquid crystals: chiral p,p'-dialkoxyazobenzenes and their cyclopalladated dinuclear complexes
No full textTo prepare chiral metallo-mesogens with ferroelectric properties, new azobenzene compounds, HLN(n), bearing a chiral substituent have been synthesized. These ligands consist of two aliphatic chains of variable length, one of which contains a stereogenic center located in the para and para′ positions of an azobenzene core. The chiral groups (R*O) are as follows: N = 1, (R)-(-)-menthol; N = 2, (S)-(-)-β-citronellol, and N = 3, (R)-(-)-2-octanol; the aliphatic chains are linear n-alkoxy groups CnH2n+1O (n = 7, 10, 12, 14). Only the HL2(n) species display liquid-crystalline properties giving cholesteric or smectic A mesophases. The HLN(n) ligands react with [Pd(PhCN)2Cl2], to give the corresponding chloro-bridged dinuclear cyclopalladated products {Pd[LN(n)](μ-Cl)}2 as 1:1 mixtures of isomers arising from the nonselective attack of the palladium on the benzene ring bearing the chiral alkoxy group or on the benzene with the aliphatic alkoxy chain. The (Pd[L2(n)](μ-Cl)}2 compounds and the (Pd[L3(n)](μ-Cl)}2 (n = 10, 12, 14) exhibit smectic mesophases (Sc* in {Pd[L2(7)] (μ-Cl)}2, {Pd[L2(10)](μ-Cl)}2, {Pd[L3(10)](μ-Cl)}2, and {Pd[L3-(14)](μ-Cl)}2,SA in {Pd[L2(12)] (μ-Cl)}2, {Pd[L2(14)](μ-Cl)}2, {Pd[L3(12)]μ-Cl)}2). The Pd[LN(n)]-(μ-Cl)}2 compounds have been converted into the corresponding iodo analogues {Pd[LN(n)] (μ-I)}2. The chloro complexes display a richer mesomorphism than the respective iodo compounds
Responsabilità professionale e gestione del rischio in psichiatria
No full textIl capitolo fornisce una panoramica sullo sviluppo della responsabilità professionale in ambito psichiatrico, evidenziando le criticità e le possibili evoluzioni del tem
Transition metals complexed in ordered mesophases. XV. Synthesis, characterization and mesomorphic properties of new potentially ferroelectric liquid crystals: acetylacetonate p,p'-dialkoxyazobenzene mononuclear palladium(II) complexes
No full textHeteroligand Palladium Complexes with One or Two Chiral Centres
No full textA series of chiral mononuclear palladium(II) complexes, [(Az(n))Pd(L-m)], I-VIII, have been synthesized. Herein the Az(n)Pd fragments represent the cyclopalladated 4-tetradecyloxy-4'-alkoxyazobenzene bearing an optically active carbon atom in a terminal alkoxy chain while HLm is the anion arising from the achiral N-[4'(dodecyloxy)resorcylidene]-4-(alkyl)anilines or the N-[4'-(dodecyloxy) resorcylidene]-4-(alkoxy)anilines containing a stereogenic center in a lateral chain. The optically active alkoxy tails are derived by S-(-)-beta-citronellol and R-(-)-2-octanol. Thermotropic mesomorphism, namely nematic and smectic phases, has been observed for almost all the complexes, with higher thermal stability and clearing temperatures of the same order or lower than those of the corresponding organic ligands
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
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