1,720,960 research outputs found
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
Mineralogical study of historical bricks from the Great Palace of the Byzantine Emperors in Istanbul based on powder X-ray diffraction data
No full textThis study concerns the Quantitative Phase Analysis (QPA) of historical bricks coming from the complex of the Great
Palace of the Byzantine Emperors in Istanbul. The studied samples are characterised by different chemical compositions (low and high calcium content), variable firing temperatures and different amounts of soluble salts as damage products.
In the low-Ca samples, the decrease of the phyllosilicate content (from 23.4 to 6.9 wt%) is associated to the increase of the
amorphous fraction (from 24 to 48%). This clear negative correlation between the phyllosilicate content and the amorphous fraction indicates that in low-Ca systems vitrification processes are overwhelming with respect to nucleation and recrystallisation processes. By contrast, high-Ca samples present newly formed Ca(Mg) silicates (diopside from 5.7 to 27.2%; anorthite from 1.4 to 8.7%) and aluminium silicates (gehlenite only in two samples, 6.2 and 7.7%) associated to the decrease of quartz (from 27.7 to 11.5%), phyllosilicate (from 6.5% until complete break down) and amorphous (from 30 to 14%) phase fractions. These findings support the role played by the CaO(MgO) content deriving from carbonates decomposition which reacts with Al2O3 and SiO2 oxides from dehydroxylated clay minerals and quartz grains. The above results have been obtained by X-ray powder diffraction data using the combined Rietveld refinement – internal standard method in order to estimate both the crystalline and the amorphous phase fractions. In addition, the coexistence of two distinct plagioclases in high-Ca samples was modelled as follows: a primary albite, which tends to incorporate Ca during the firing process as demonstrated by the increasing of gamma crystallographic angle, and a newly formed anorthite. Finally, by difference between the X-ray fluorescence data and the chemical compositions inferred by QPA, it proved possible to roughly estimate the residual chemical composition attributable to the amorphous fraction. On the basis of our data,we believe that Rietveld refinement combined with the internal standard method represent a powerful tool to better characterise complex polycrystalline and amorphous mixture as in the case of historical bricks
Early evidences of vitreous materials in Roman mosaics from Italy: An archaeological and archaeometric integrated study
No full textThis work displays the lines of a project about vitreous materials used in Roman Republican Age opus vermiculatum mosaics from Italy. This mosaic technique, originated in Egypt and Greece during the Hellenistic Age, testifies the fist evidences of vitreous materials used in mosaics: faience and glasses. The use of these materials in vermiculata mosaics from Italy was almost unknown when this research was started, so it was necessary to map and characterize the whole mosaic production. After a survey operated by a portable digital microscope, a reduced number of samples were collected to perform a laboratory characterization (OM, SEM–EDS, XRD). Data have been completed by an isotope ratio characterization (SIMS) to investigate the glasses raw materials provenance
Ancient glass deterioration in mosaics of Pompeii
No full textThe aim of the present project is to evaluate the deterioration degree of ancient glass surface used as mosaic materials (tesserae) in Pompeii's 'ninfei a scala'. Specimens come from the fountain in the 'Domus del Centenario' (Pompeii, IX, 8), built starting from the 1st century AD and have been studied within a broader project on the Domus involving archaeologists, engineers, geologists, chemists and materials scientists. Using data from both non-destructive analyses (OM, XRD, SEM-EDS, UV-VIS) and those which requiring few milligrams of specimens (DTA-TGA, ICP-AES), a complete database of the tesserae based on classification by colour, materials characterisation and evaluation of their deterioration has been constructed. After characterisation, specimens were replaced in their original position in the mosaic using suitable mortars. One of the glassy tesserae that was analysed for surface deterioration-gave interesting results. The glass, coloured opaque red from Cu 2O micrometric crystallisation, turned green at the surface as a result of copper and lead leaching out and depositing as carbonate and sulphate salts. The glass production technology appeared to be very similar to that found in Nimrud (North Iraq) during the 8th century BC, the glass showing a similar chemical composition and deterioration. The identification of colour variations makes it possible to correctly read the decoration system and the archaeometric analysis will help to identify the site and production technique of materials
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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