1,721,044 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
“Lettura-scrittura nella conoscenza dell’adolescente borderline.: considerazioni preliminari”
No full textChemical characterization of pope pius vii ancient ecclesiastical vestment by a multi-analytical approach
No full textThis paper presents a multi-analytical investigation performed for the study of the ecclesiastical vestment, with insignia, of Pope Pius VII, painted from the end of the 18th up to the beginning of the 19th century, made of five clothing elements: chasuble, stole, maniple, chalice veil and purse. The aim of this research was to assess the conservation state of the silk and painted backgrounds; to define the manufacturing technique of the work; to localize, if present, the underdrawing and any retouching; to identify the pigments and, where possible, the binders used. A diagnostic protocol was developed based on preliminary investigations through multiband imaging techniques known as MBI (visible, ultraviolet-induced visible luminescence (UVL), near-infrared reflected (NIR) and infrared reflected false color (IRRFC) photography). The images acquired with MBI techniques ensured a more specific choice of spots to be analyzed directly in situ by non-invasive techniques. In particular, portable digital optical microscopy and X-ray fluorescence (XRF) were performed. Two fragments detached from the chasuble were also analyzed by microFT-IR, microRaman, scanning electron microscopy (SEM-EDS) and gas chromatography/mass spectrometry (GC-MS). Application of the multi-analytical protocol enabled the materials used to be characterized and helped to define the peculiar execution technique used. The presence of an underdrawing made with a carbon pencil was highlighted by MBI. Red lakes, iron-based pigments and copper-based pigments have been identified on the painting palette, applied with arabic gum as a binder
An integrated approach to the study of a reworked painting “Madonna with child” attributed to Pietro Lorenzetti
No full textThe painting "Madonna with Child", attributed to Pietro Lorenzetti (14th century) and reworked around the middle of the 16th century, was studied by several techniques in order to characterize the materials used in the original and in the repainted areas. FORS, light microscopy, ESEM-EDX, ToF-SIMS and GC-MS were used. Red ochre and raw sienna earth were identified by FORS in the original parts of the painting. On the repainted parts of the panel, cinnabar, ultramarine blue and lead white were found. By means of GC-MS and ToF-SIMS measurements it was possible to identify the organic binding media used in the preparatory and painted layers. © 2013 Elsevier Masson SAS
An integrated multimethodological approach for characterizing the materials and pigments on a sarcophagus in St. Mark, Marcellian and Damasus catacombs
No full textThe increasing interest and debate about the extent of the polychromy of ancient artefacts is generating more attention to the study of the traces of colour remaining on their surfaces. The small amount of these traces lead to a new approach for their characterization in order to limit sampling and hopefully avoiding it. The application of a protocol based on imaging techniques integrated with data obtained from single-spot techniques such as X-ray fluorescence (XRF) and fibre-optic reflectance spectroscopy (FORS) provides high-quality information about the materials. The integrated protocol has been applied in the study of a sarcophagus in San Callisto complex in Rome, and the efficacy of its use is confirmed by the data obtained. The sarcophagus, dating back to fourth-century C.E., is located in Saints Mark, Marcellian and Damasus catacombs. The study was focused on characterization of materials through a multidisciplinary approach with in situ non-invasive techniques (multispectral photography, visible-induced luminescence, XRF and FORS) and microinvasive analytical methods in order to identify the marble’s provenance through a consolidate multianalytical approach (X-ray diffraction, optical microscopy, isotopic ratios). In situ analyses were conducted in critical environment due to the high humidity (RH = 100 %), low temperature (T = 15 °C) and high CO 2 levels, all factors representing a challenge for either the operators or the electronic instrumentations. This work is included in a wider research project aimed to enlighten the use of colours on the sculptures in the roman time and to better define the composition of used raw materials
Characterization and contemporary replicae of Art Noveau coloured glass
No full textCurrently the importance of the application of non-invasive and portable techniques to the characterization of glass is well known. However, despite the large number of publications on medieval glass, few studies have been performed on early modern glass.
Since the opportunities to sample or to move the work of art out of the conservation location are very limited, the application of non invasive and portable techniques appears to be the best way to perform an in-depth characterization of the chromophores and raw materials even though the complexity of interpreting the results and the lack of references necessitate a preliminary phase of testing on standard and reference samples.
In this study a collection of colored and opalescent glasses from the first half of the 20th century and some standard samples of cobalt and cadmium glasses produced ad hoc at the Vicarte Centre (Universidade Nova de Lisboa) were analyzed using both traditional (XRF, SEM-EDS, XRD and UV-Vis-NIR) and portable and non-invasive techniques (XRF, FORS).
The standard samples consist of 21 glasses different base compositions (soda-lime, potash and mixed alkali) and different amounts of chromophores. For cobalt colored glasses different amounts of cobalt (0.5, 0.75 and 1% wt) were added to each base composition (9 samples). Also, yellow to orange and ruby red colorations were obtained by modulating the cadmium/sulfide and cadmium/selenium ratios.
The cobalt blue glass absorption spectra detected by FORS are usually characterized by three sub-peaks located around 530 nm, 590 nm and 650 nm due to the cobalt tetrahedral coordination. A change in the base composition of the glass could, however, affect the three-peak position due to a change in the ligand field strength.
The influence on the FORS spectra of a different base composition and amount of soda present in the glasses (detected by SEM-EDS and XRF) was studied. For glasses with soda content under 15% (some soda-lime samples and mixed base glasses), the resolution of the three-peak absorption band of cobalt is poor. The band appears to be broad, unsymmetrical, and centered around 550 nm even though the characteristic triplet was detected when the amount of soda increased to between 15% and 29%. A shift of about 10 nm in the position of the peaks can be observed in all glasses with a potash base.
The study of the glasses colored by CdS and Se is still in progress, and the results will be available soon
The ancient use of colouring on the marble statues of Hierapolis of Phrygia (Turkey): an integrated multi-analytical approach
No full textThe interest about the extent of the polychromy of ancient artefacts has increased in the last 10 years, increasing our knowledge on classical art, still often perceived as perfectly white. As a consequence, the development of methodologies allowing the detection and interpretation of the traces of colour remaining on the surfaces of archaeological artefacts has gained momentum. This paper presents the results of a multi-disciplinary research carried out about the painting materials used in producing selected marble statues excavated from the archaeological site of Hierapolis of Phrygia (Turkey), integrating the art-historical approach and the archaeometric data. The artefacts discussed in this paper were excavated in the archaeological site of Hierapolis in the course of several years by the Italian archaeological mission (MAIER). The objects include the reliefs and decorative statuary of the Severan Theatre and the statues excavated from the North Agora of the archaeological site, which are currently preserved in the museum of Hierapolis-Pamukkale. The analytical protocol, based on non-invasive imaging techniques (ultraviolet fluorescence images—UVf and visible induced luminescence—VIL), was performed directly outdoor, in the archaeological site. Few microsamples were selected, collected and subjected to laboratory analyses (XRD, FT-IR, SEM-EDS and HPLC-DAD). The integrated protocol allowed for the identification of the colouring materials used in producing the polychromies under study
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