1,721,048 research outputs found
Electronic properties and photoelectron circular dichroism of adsorbed chiral molecules
Full text linkWe report on an angle-resolved photoemission investigation of the valence states and chiral properties of a nonchirally oriented phase of tartaric acid deposited on a Cu(110) surface, observed with circularly polarized light. The two optical enantiomers R,R and S,S of tartaric acid, separately deposited, produce (40,23) overlayers which show a large dichroic effect and enantiomeric behavior all over the valence energies. The dichroic effects are displayed by native chiral molecular states and molecule-copper interface states. Density-functional theory calculations of the site-resolved density of states analyze the formation of hybrid states at the tartaric acid-copper interface and suggest that an observed interface state acquires chirality on binding.Fil: Ferrari, L.. Consiglio Nazionale delle Ricerche; ItaliaFil: Moras, P.. Consiglio Nazionale delle Ricerche; ItaliaFil: Gori, P.. Consiglio Nazionale delle Ricerche; Italia. Università di Roma; ItaliaFil: Turchini, S.. Consiglio Nazionale delle Ricerche; ItaliaFil: Zema, N.. Consiglio Nazionale delle Ricerche; ItaliaFil: Palma, A.. Consiglio Nazionale delle Ricerche; ItaliaFil: Fujii, J.. Consiglio Nazionale delle Ricerche; ItaliaFil: Vobornik, I.. Consiglio Nazionale delle Ricerche; ItaliaFil: Alejandro, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. The Abdus Salam. International Centre For Theoretical Physics; ItaliaFil: Catone, D.. Consiglio Nazionale delle Ricerche; ItaliaFil: Prosperi, T.. Consiglio Nazionale delle Ricerche; ItaliaFil: Carbone, C.. Consiglio Nazionale delle Ricerche; Itali
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 Aggregates of Indan-1-ol with Secondary Alcohols and Water: Laser Spectroscopy in Supersonic Beams
No full textOne color, mass selected resonant two-photon ionization (1cR2PI) spectra of supersonically expanded bare (R)-(-)indan-1-ol (IR) and its complexes with chiral and achiral mols. (solvent) have been investigated. The excitation spectrum of bare IR has been analyzed and discussed on the basis of theor. predictions at the B3LYP/6-31G** level of theory. The excitation spectra of its diastereomeric complexes with (R)-(-)-and (S)-(+)hexan-2-ol (XR or XS, resp.) and water (W) are characterized by significant shifts of their S0 S1 band origin relative to that of bare IR. The extent and the direction of these shifts are found to depend upon the structure and the configuration of solvent and are attributed to different short-range interactions in the ground and excited [IRsolvent] complexes. In particular the [IRW]n complexes display band origins blue-shifted relative to that of bare IR, attributed to the presence of an O-H.pi. electrostatic interaction between IR and W in [IRW]n. The [IRXR] and [IRXS] equil. structures have been calcd. by a mol. dynamical (MM3) sampling and PM3 semiempirical local optimization
Excited state dynamics of Zn–salophen complexes
Full text linkZn-salophen complexes are a promising class of fluorescent chemosensors for nucleotides and nucleic acids. We have investigated, by means of steady state UV-Vis, ultrafast transient absorption, fluorescence emission and time dependent density functional theory (TD-DFT) the behavior of the excited states of a salicylidene tetradentate Schiff base (Sal), its Zn(II) coordination compound (Zn-Sal) and the effect of the interaction between Zn-Sal and adenosine diphosphate (ADP). TD-DFT shows that the deactivation of the excited state of Sal occurs through torsional motion, due to its rotatable bonds and twistable angles. Complexation with Zn(II) causes rigidity so that the geometry changes in the excited states with respect to the ground state structure are minimal. By addition of ADP to a freshly prepared Zn-Sal ethanol solution, a longer relaxation constant, in comparison to Zn-Sal, was measured, indicative of the interaction between Zn-Sal and ADP. After a few days, the Zn-Sal-ADP solution displayed the same static and dynamic behavior of a solution containing only the Sal ligand, demonstrating that the coordination of the ADP anion to Zn(II)leads to the demetallation of the Sal ligand. Fluorescence measurements also revealed an enhanced fluorescence at 375 nm following the addition of ADP to the solution, caused by the presence of 2,3-diamino naphthalene that is formed by demetallation and partial decomposition of the Sal ligand. The efficient fluorescence of this species at 375 nm could be selectively detected and used as a probe for the detection of ADP in solution.[GRAPHICS]
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