1,720,959 research outputs found
Transport Amphoras from Gravisca to the Eastern Aegean during the Greek Archaic Period (7TH-6TH C. Bc): A Multidisciplinary Approach for Characterization, Manufacturing, Provenance and Trade
No full textThis paper described a baseline for a multidisciplinary approach to the mineralogical and chemical characterization of eighteen fragments of archaic transport amphoras (7 th-6 th centuries BC) found at Gravisca archaeological site (Lazio, Italy) attributed to an Eastern Aegean provenance (six from Samos, three from Miletus, three from Chios and three from Klazomenai). The samples have been typed on the evidence concerning archaic manufactory techniques by using X-ray powder diffraction (XRPD) associated with quantitative phase analysis (QPA), optical (OM) and electron microscopy (SEM). Following Inductive Coupled Plasma Spectros-copy (ICP), compositional data analysis has been for the first time applied to selected geochemical proxies combining rare earth elements and selected heavy metals concentration in Hierarchical Agglomerative Cluster (HAC). This innovative approach allows to distinguish different sources of the raw materials used from different geological and geographical areas. Multivariate statistical treatments via Principal Component Analyses (PCA) open the possibility to group the sherds into clusters, comparing the results with the HAC application allowing to validate the methodology. Two distinct centres associated with Samos manufactory appear to be operating during 7 th-6 th centuries BC, which could be related to different production periods or even different production areas. The new data concur with a more straightforward historical reconstruction of archaic Poleis manufactory and commercial activity toward Etruria and the Mediterranean and with a new methodological approach to archaeometry
Cation disordering in ankerite as a function of Fe content
No full textOrder–disorder transitions in minerals are of significance for technological applications and for the development of models that aid the understanding of the dynamics and composition of the Earth’s interior. The present study investigates the effect of Fe content in ankerite, Ca(FexMg1−x)(CO3)2 (0 ≤ x ≥ 0.7, R3̄ space group), on the distribution of cations in its crystal structure as a function of temperature. This investigation was conducted using ex situ experiments in a piston cylinder apparatus performed at 2–3 GPa and variable-temperature conditions (450–1000 °C). Crystal structure refinements, using single-crystal X-ray diffraction data, indicate that the temperature of the order–disorder phase transition in ankerite, when the space group changes from R3̄ to R3̄c, is significantly influenced by the amount of Fe in the mineral’s crystal structure, being full disordering conditions attained at 1000 and 800 °C in ankerites with x = 0.3 and x = 0.7, respectively. Prior to undergoing the order–disorder phase transition, it is shown that Fe exhibits a greater aptitude than Mg to exchange in the place of Ca (and vice versa). Mg, conversely, has a tendency to be bound at the M2 site or to exchange in smaller quantities than Fe. Furthermore, the significance of Fe as a parameter influencing the chemo-physical behavior of ankerite, as well as the temperature and character of the disordering process, is highlighted. This has the potential to significantly impact the mineral physics of ankerite under non-ambient conditions, particularly with regard to compressibility, phase stability, thermal and electric conductivity, and its role in the Earth’s mantle geophysical modeling
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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