1,721,057 research outputs found
Raman study of a ‘Tabula Colorum Physiologica’ in a 1686 printed journal
No full textA Table painted in 1686 with spots of colors on paper was investigated. It appears that the Table is composed of pure pigments, and their mixtures in a 1:1 proportion. However, there were some problems when analyzing the pure compounds and the mixtures, due to the interaction of some pigments, as degradation had occurred. Possible explanations of the nature of the compound are analyzed and discussed
studio in spettrometria micro Raman della policromia di terrecotte campane dei musei di Capua e S. Maria Capua Vetere
No full textLe analisi di una serie di frammenti di antefisse fittili di provenienza campana mediante indagini in spettrometria micro Raman ha mostrato la presenza di interessantyi pigmenti e coloranti. Mentre sono presenti pigmenti usuali, insoliti risultano alcuni coloranti come il giallo di zafferano e l'indaco, sulla cui persistenza esistono pochi dati
Analisi del contenuto di alcuni Unguentari Pompeiani
No full textUna ricerca svolta sul contenuto di un gruppo di balsamari di Pompei ha portato ad evidenziare una serie di composti organici di varia natura. Mediante tecniche di spettroscopia infrarossa, microRaman e di gascromatografia applicata alla spettrometria di massa si sono identificati vari componenti noti e alcuni finora incogniti. I composti inorganici identificati possono fornire indicazioni sulla provenienza di materiali o preferenze locali per prodotti disponibili, le sostanze organiche, le tecnologie di preparazione del cosmetico. In generale, dall'esame dei dati qui riportati, risulta una cosmesi di tipo economico, rispetto a siti contemporanei posti in zone limitrofe. Non mancano però alcune singolarità, come l'impiego dell' huntite e della jarosite, materiali di probabile provenienza egiziana
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
Photoluminescence investigations on alumina ceramic bearing couples tested under different angles of inclination in a hip joint simulator.
No full textAseptic loosening due to wear and dislocation of the implant represents the main complication after total hip arthroplasty. To gain more insight into the influence of the implant position on wear, commercial alumina couplings have been tested in a hip joint simulator under three different angles of cup inclination (23°, 45°, 63°) with respect to a horizontal plane. The planned length of the test was ten million cycles. However, the test was stopped at 5.5 million cycles due to the fracture of one of the femoral heads, tested with at angle of 63°. The residual stress state in the worn acetabular cups and in the fractured femoral head were evaluated by the frequency shift and broadening of the R1 and R2 fluorescence bands due to the Cr3+ ions naturally present in alumina ceramics as trace impurities.
The gravimetric measurements did not show significant differences among the three different inclinations tested, in agreement with previous simulator studies, but in disagreement with in vivo findings. The fluorescence measurements allowed to affirm that an angle of 63° represents a worsened mechanical condition for the prosthetic component, with a consequently higher probability of fracture and/or damage potentially conducive to massive wear. In the light of the fluorescence results, it did not appear surprising that the femoral head that fractured was the one being tested at 63°
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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