1,720,989 research outputs found
Catalan imitations of the ligurian taches noires ware in Barcelona (18th-19th century) : an example of technical knowledge transfer
Get PDFThe ware called Taches Noires was developed in Albisola (Liguria, NW Italy) during the 18th century. In just a few years, it spread all over the Mediterranean (Italy, France, Spain, Tunisia, and Greece) and also in the New World (Canada, the Caribbean Islands, and Mexico). The success of the Taches Noires ware was so massive that it was soon copied by Spanish and French workshops. A collection of Catalan imitations and Ligurian imports found in Barcelona were analysed and compared to previously existing data from Barcelona productions, as well as reference samples from Albisola. The study proved the presence of both local imitations and original Albisola imports. The analysis showed a homogeneous product of high technical quality for the Albisola pottery. On the contrary, the local imitations presented a greater diversification in the choice and manipulation of the raw materials, probably related to the existence of different workshops engaged in the manufacturing of these products. Nevertheless, for one of the local groups, ceramists adopted a glaze recipe similar to the one used in Albisola, clearly indicating a direct transfer of knowledge, and possibly of potters, from Albisola to Barcelona
Archaeometric Classification of Scattered Marble Fragments to Help the Reconstruction of Statues
Get PDFA multi-technique approach combining petrographic, cathodoluminescence, and stable isotope analyses is commonly used in provenance studies of archaeological marbles. In the present paper, this characterization approach transcends provenance, and it is applied to the reconstruction of fragmented sculptures. The potential of this novel application of archaeometric measurements is illustrated with a case study consisting in 16 scattered marble fragments retrieved from a Roman villa (Els Munts) near Tarraco (presently Northeastern Spain). The samples were grouped taking into account their similarity in quantified parameters such as the cathodoluminescence color clusters and the stable carbon and oxygen isotopic ratios. The results permitted classification of the fragments into three groups corresponding to three different statues depicting Antinous (7 fragments), Minerva goddess (4 fragments), and an undetermined character (3 fragments). Two other fragments could not be ascribed to any particular statue. The archaeometric grouping provides arguments that can be used to confirm or refute archaeological hypotheses of statue reconstructions
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
Identification of microcrystalline phases in Lead Glazes of ceramics from 17th-19th centuries: archaeometric implications
No full textPrograma de Doctorat: Ciències Experimentals i TecnologiesCrystalline phases inside ancient glazes can have different origins: unreacted compounds (thus
already formed before the glaze formation), crystallites developed during the glaze production or
devitrification crystals formed after the glaze production (during burial by weathering processes).
This study deals with the identification of the crystalline phases developed during the firing of lead
glazes in ceramics from the 17th to 19th centuries. The formation of the crystallites during firing and
their distribution depends on the original composition of the glaze and body (clay, stonepastes, etc.),
the use of raw or pre-fired materials and on the firing conditions (temperature and atmosphere of the
furnace, single or double firing, etc.). Therefore, the detailed investigation of the crystal inclusions
and the microstructural heterogeneities in the glazes yield information on the nature of the objects,
the raw materials used, their thermal history as well as other important aspects of the glass making
technology.
This research develops a methodological approach to study of ceramic glaze microstructures based
on the thin section. Starting from its present role as an accessory identification technique, thin-section
petrography turns here into a pivotal tool to characterize micro-crystals embedded in ceramic glazes
and hence characterize the glazes themselves. Firstly, the crystallites are located and described using
thin-section petrographic methods. Special attention is paid to the description of the morphologies
and the optical features of the crystallites. Then, the thin section petrography data are linked to
compositional and structural data obtained from other analytical tools, such as SEM (scanning
electron microscopy), EPMA (electron probe micro-analyser), μ-Raman (micro-Raman) and SR-
μXRD (synchrotron-radiation X-ray micro-diffraction). For each mineral phase identified, chemical,
mineralogical and structural data are collected in such a way to obtain a correlation between
morphological and analytical data. Once established, this correlation could allow a quick and easy
identification of the crystallites using a petrographic microscope and therefore avoiding the repetition
of an exhaustive identification protocol involving the use of expensive characterization technique
Identification of microcrystalline phases in Lead Glazes of ceramics from 17th-19th centuries: archaeometric implications
No full textCrystalline phases inside ancient glazes can have different origins: unreacted compounds (thus
already formed before the glaze formation), crystallites developed during the glaze production or
devitrification crystals formed after the glaze production (during burial by weathering processes).
This study deals with the identification of the crystalline phases developed during the firing of lead
glazes in ceramics from the 17th to 19th centuries. The formation of the crystallites during firing and
their distribution depends on the original composition of the glaze and body (clay, stonepastes, etc.),
the use of raw or pre-fired materials and on the firing conditions (temperature and atmosphere of the
furnace, single or double firing, etc.). Therefore, the detailed investigation of the crystal inclusions
and the microstructural heterogeneities in the glazes yield information on the nature of the objects,
the raw materials used, their thermal history as well as other important aspects of the glass making
technology.
This research develops a methodological approach to study of ceramic glaze microstructures based
on the thin section. Starting from its present role as an accessory identification technique, thin-section
petrography turns here into a pivotal tool to characterize micro-crystals embedded in ceramic glazes
and hence characterize the glazes themselves. Firstly, the crystallites are located and described using
thin-section petrographic methods. Special attention is paid to the description of the morphologies
and the optical features of the crystallites. Then, the thin section petrography data are linked to
compositional and structural data obtained from other analytical tools, such as SEM (scanning
electron microscopy), EPMA (electron probe micro-analyser), μ-Raman (micro-Raman) and SR-
μXRD (synchrotron-radiation X-ray micro-diffraction). For each mineral phase identified, chemical,
mineralogical and structural data are collected in such a way to obtain a correlation between
morphological and analytical data. Once established, this correlation could allow a quick and easy
identification of the crystallites using a petrographic microscope and therefore avoiding the repetition
of an exhaustive identification protocol involving the use of expensive characterization technique
La ceràmica de Barcelona entre els segles XIII i XVIII a través de la seva caracterització arqueomètrica: el paper de l'anàlisi petrogràfica
Get PDFEl treball de recerca d’aquesta tesi doctoral se centra en la caracterització petrogràfica dels materials ceràmics (segles XIII-XVIII) de la ciutat de Barcelona, aquesta última entesa no només com centre productor, sinó també com un important centre de recepció i d’exportació. Fins a dia d’avui, els estudis petrogràfics sobre els materials ceràmics apareguts a les excavacions de la ciutat de Barcelona han estat molt escadussers i puntuals i han centrat la seva atenció sobre ceràmiques de cronologies anteriors respecte el marc temporal d’aquesta tesi. Així doncs, la present contribució constitueix el primer treball petrogràfic sistemàtic sobre una mostra analítica àmplia que destaca tant per la varietat de les classes considerades- fins a 15 classes ceràmiques diferents- com per l’ampli ventall cronològic que abraça. Els objectius de la caracterització petrogràfica, duta a terme sobre les produccions aparegudes a les excavacions barcelonines i que han estats analitzades químicament de manera prèvia, contemplen tant l’estudi dels cossos ceràmics com els dels seus revestiments. Els casos d’estudi presentats en aquest treball mostren una àmplia variabilitat de matèries primeres i de tecnologies en la producció ceràmica local a la Barcelona medieval i moderna. Les matèries primeres es poden relacionar amb categories ceràmiques especifiques i probablement amb diverses àrees de producció a la ciutat de Barcelona, d’acord amb les diferents formacions geològiques que afloren en la zona. Les inclusions metamòrfiques (principalment fragments de pissarra, esquist i granitoide, així com els minerals derivats d’aquests, incloent també els minerals pesants) són presents en quantitats variables en totes les fabriques, molt sovint associats a microfòssils calcaris. Igualment, pel que fa a les importacions, la comparació amb mostres de referència ha posat de manifest la presència, a la pròpia ciutat, de materials que es poden adscriure a altres centres productors espanyols, com València i Sevilla i, més en general, als sectors meridionals de la Península; mentre que, fora d’Espanya, destaquen Itàlia i el nord d’Àfrica. A més a més, l’estudi petrogràfic d’una producció local de vaixelles verdes ha permès reconèixer la seva presència en els contextos d’excavacions provençals. L’estudi dels revestiments, que ha integrat l’observació dels cossos ceràmics, ha permès caracteritzar les diferents produccions en relació a la seva tecnologia de producció, reconèixer la presència de diferents tècniques dins d’una mateixa classe ceràmica o entre classes ceràmiques distintes però que comparteixen una recepta de pasta similar. Finalment, en el cas de les imitacions, gràcies a l’estudi dels vidriats ha estat possible establir una sèrie de correspondències precises amb les manufactures lígurs.The petrographic results on 295 ceramic samples, dated from the 13th century to the 18th century are presented. The samples, collected from about twenty archaeological interventions carried out in the city of Barcelona, are representative of the local production of glazed coarse wares, cooking wares, majolica and tableware. The aim of the study is to characterize the ceramic fabrics from a compositional and technical point of view, to identify the possible sources of the raw materials and to integrate the results of the chemical data previously obtained. The possibility of studying so many samples over such a long period of time enabled the recognition of specific choices in the exploitation of raw materials, the identification of provenance markers and the acknowledgement of imported pottery and imitations
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
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