1,721,155 research outputs found
Ag X-ray fluorescence on different thickness and concentration layers
No full textThis work derives from the requirement to investigate on the silver surface enrichment of objects of historical and artistic interest using the X-ray fluorescence non-destructive technique (XRF). The aim is the thickness estimation through the experimental relationship between K-alpha/K-beta and K-alpha/L-alpha of Ag as a function of the thickness. Measurements on silver sheets of different thicknesses and three concentrations are carried out using a XRF spectrometer with a maximum voltage of 50 kV. The results allow to analyse the plating layer of silver objects also to make other interesting considerations
Carbon 14 dating of some materials found during the excavation of the catacomb of san gennaro in naples: Old research and new data
No full textThe review of an old14C dating investigation and the new radi-ometric analysis on 10 different samples, conducted by the Center for Isotopic Research on Cultural and Environmental heritage (CIRCE) of the University of Campania “Luigi Vanvitelli”, through the AMS (Accelerator Mass Spectrometry), offer useful elements to date the excavation and relative phases of the catacomb of St. Ianuarius, the most important Late Antique cemetery in Naples. Several excavations have been carried out in the catacomb since the nineteenth century, not always conducted in a systematic manner and published only in part. In the last decade, the Pontifical Commission for Sacred Archeology has started the edition of the old excavations and finds, thanks also to the archaeometric analysis. The recalibration of a previous measurement of a beam fragment discovered during the excavations carried out in the 1970s, based on the new IntCal 13 Calibration Curve and the Oxcal Software 4.3, allowed the finding to be more correctly dated to 530-659 A.D. (±2σ). The AMS reduces not only the14C isotopic measurement time but also the weight of the material used for dating. Furthermore, advances in chemical treatments on samples of different nature make it possible not only to quantify radiocarbon in a wider range of organic materials but also, through an innovative calcite extraction process, dating from mortars (first mortar radiocarbon dating of the catacombs analyzed). The results obtained in this study expand our knowledge on the catacomb not only in Late Antiquity and in the Middle Ages, but also in the following centuries (see the dating of the samples Sgn 1, Sgn 2, Sgn 3, Sgn 6)
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
High resolution archaeoenvironmental study of a Copper age site in the Central Alps. (Ossimo “Anvòia”, Italy).
No full textVariations 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
Può l’analisi cefalometrica dei tessuti molli definire la struttura del viso di Leonardo da Vinci?
No full textAppropriate 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
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