1,720,978 research outputs found
The Identification of Copper Oxalates in a 16th Century Cypriot Exterior Wall Painting using Micro FTIR, Micro Raman Spectroscopy and Gas Chromatography Mass Spectrometry
No full textAnalysis of paint samples from a 16th C. wall painting in the church of Agios Sozomenos in Galata, Cyprus resulted in the identification of a copper-based, pigment degradation product - a hydrated copper oxalate, analogous to the naturally occurring blue-green mineral Moolooite. The identification of copper oxalate, a deterioration (alteration) product more often associated with the deterioration of bronze was possible through the integrated use of both micro-FTIR in reflectance for spot analysis of areas on the surface of an embedded cross-section, and FTIR reflectance imaging for the localisation of the presence of copper and calcium oxalates within the stratigraphy of the painting. Further, micro-Raman spectroscopy was employed for the analysis of unembedded fragments of the painting, confirming the presence of both copper oxalate and calcium oxalate. Finally, novel methods for the removal of salt interferences were employed for analysis using Gas Chromatography-Mass Spectrometry (GC-MS), which revealed the presence of both oxalate and phosphate ions and, following multivariate analysis of the amino acid profile, identified casein as the binder of the paintings. The imaging of calcium oxalates within the stratigraphy of wall painting samples is important and significant not only for the study of copper-based pigments in general, but especially for the analysis of pigments used for painting on exterior surfaces
Potential role of LIPS elemental depth profiling in authentication studies of unglazed earthenware artifacts
No full textWe focused on the behaviour of elemental distributions in unglazed earthenware artifacts. The potential role of the elemental depth profiles, as measured using a portable laser induced plasma spectroscopy (LIPS) device, in discriminating between genuine unearthed archaeological findings and modern counterfeits was investigated. Measurements were carried out on a set of ancient unglazed earthenware samples from archaeological excavation and on some corresponding modern artifacts. The analyses pointed out that the elements exhibiting the most significant and repeatable modulations were iron and calcium. A systematic depletion of the former was observed in all the samples analysed, without any possibility of discrimination, whereas calcium had different behaviours. A recurrent presence of high-amplitude, broad, and structured calcium content peaks in proximity of the surface of genuine unearthed samples was measured, a feature that was not observed for modern artifacts. This result provides the first evidence of the possible use of calcium depth distribution measured using LIPS analysis as a marker in authentication studies of unglazed earthenware artifacts. © 2012 The Royal Society of Chemistry
Dependence of Nd:YAG laser derusting and passivation of iron artifacts on pulse duration
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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
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