1,720,967 research outputs found
Ferrocene derivative molecules covalently attached to Si (100) : Electrochemistry and Surface Analysis
No full textEffects of carotenoid supplementation on colour expression, oxidative stress and body mass in rehabilitated captive adult kestrels (Falco tinnunculus)
No full textCarotenoids are considered a limited resource for animals because they are not synthesised by the body. Birds use carotenoids, mainly xanthophylls, for physiological functions, such as anti-oxidant activity, and for colour expression; hence, they need to shunt carotenoids between competitive demands. Recent studies suggest that the anti-oxidant role of xanthophylls might not be as important as previously thought and that at high concentrations they may, in fact, acquire pro-oxidant properties. In this work, we studied the effects of a moderate xanthophyll supplementation (115 mg of carotenoids/kg diet/day; 4 weeks) on serum carotenoids, serum concentration of reactive oxygen metabolites (ROMs), serum anti-oxidant capacity (OXY), the degree of oxidative stress (OS; ROMs/OXY x 1,000), body mass, and skin colour, in rehabilitated captive adult Eurasian kestrels (Falco tinnunculus). The supplementation caused increased levels of serum carotenoids (similar to 90%), ROMs (similar to 82%), OS (similar to 115%) and an immediate loss of body mass (similar to 6.2%), but it did not affect OXY and tarsi skin hue. The red (similar to 16%) and yellow (similar to 15%) colorimetric components were increased after the first week of supplementation and the effect persisted during the rest of the experiment. Two months after the end of supplementation, serum carotenoids, OS and ROMs returned to baseline levels, however the body mass did not. Our findings suggest that, above a certain physiological threshold, carotenoids can cause detrimental effects. This is relevant for the trade-off between expression of sexual signals and the costs of maintaining/producing them
Spatial, energy, and time-dependent study of surface charging using spectroscopy and microscopy techniques
No full textSpatial, energy, and time-dependent effects induced by surface charging of conductive and nonconductive samples have been studied by spectroscopic and microscopic techniques. Surface charging of indium-tin oxide and cesium iodide has been studied by atomic force microscopy with a conducting tip and photoemission electron microscopy. Intensity fluctuations of the photoemission spectra recorded on amorphous and crystalline silicon nitride are also presented. The consequence of such effects on the determination of local physical and chemical properties of insulating materials is discussed. (c) 2007 American Institute of Physics
COORDINATION CHEMISTRY ON SURFACES: NITROGEN LIGANDS AND COMPLEXES ANCHORED ON Si(100)-H
No full text
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
REDOX-ACTIVE HYBRIDS FOR MOLECULAR ELECTRONICS: FERROCENE DERIVATIVES ANCHORED ON SILICON (100)
No full textCOMUNICAZIONE ORAL
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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