1,720,960 research outputs found
Relationships between mineralogy and porous medium of the craie tuffeau (Paris Basin, France)
No full text55 tuffeau blocks coming from historical monuments being restored, and quarries that supply building blocks for restoration work were subjected to a physical and chemical characterization. Petrographically, tuffeau consists of a continuous series that is based on the ratio between visible detrital minerals, in particular quartz and glauconite, and siliceous micrite. The Tuffeau de Saumur and the Tuffeau de Bourré are the end-members of this series. Tuffeau is an extremely porous rock, with an average total porosity of 44 % and an extended porosity spectrum. This is shown by a macroporosity and microporosity that, respectively, are 22 and 17 % (mercury porosimetry), and an average value of 9 % for infraporosity obtained from nitrogen adsorption-desorption isotherms : _ macroporosity is dominated by inter-spherules of CT opal macropores. The remaining part of the macroporous domain is originated by large-sized mineral crystals (quartz, glauconite. muscovite. sparitic calcite) along with organism test fragments ; _ microporosity is related to the compactness and arrangement style of micrite crystals. The nature of the surface of CT opal spherules, shaped like overlapping ridges, also creates a significant proportion of this microporous domain; _ infraporosity corresponds to intraleaf and intertactoïd pores of clay minerals as well as to the microroughness of some other minerals such as. in particular, micrite calcite
Identification and petrographic, physical and mechanical characterization of stones used in the chevet of the Royal Abbey in Fontevraud (Maine-et-Loire, France). Comparison with rock materials proposed for restoration.
No full textLA PIETRA DEL TEMPIO (DI HERA): CARATTERIZZAZIONE MINERO-PETROGRAFICA E GEOCHIMICA E DETERMINAZIONE DELLE CAVE DI ORIGINE. IN: IL TEMPIO DI HERA (TAVOLE PALATINE) DI METAPONTO. ARCHEOLOGIA, ARCHEOMETRIA, CONSERVAZIONE, A CURA DI L. LAZZARINI.
No full text
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
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
Volubilis (Meknes, Morocco): archaeometric study of the white and coloured marbles imported in the Roman age.
No full textInternational audienceThe ruins of the Roman town of Volubilis, located in the Middle Atlas, near Meknes, between Fez and Rabat, constitute the most important Roman archaeological site in Morocco and are included in the UNESCO World Heritage List. Volubilis became the headquarters of the Mauritania Tingitana limes after the annexation of the kingdom of Mauritania to the Roman Empire in AD 42. Evacuated by the Romans after the second half of the 3rd century, the town became the capital of the kingdom of Idriss I in AD 789. The results of an archaeometric study of the marbles imported into Volubilis during the Roman age are reported herein the sixth framework program of the European Union. Of the few coloured lithotypes that have been found, all are of Greek origin with the exception of the so-called “Portuguese pink”, a pale pink marble exploited by the Romans near Vilaviçosa in the Lusitania which, till now, has not yet been identified outside Iberia. As regards the white marbles employed in the statuary, petrographic study in thin section and the δ13C and δ18O isotopic data emphasize the frequent use of Lunense and Pentelic marbles. The latter also features among the white marbles used for crustae and architectural elements together with the dolomitic variety of Thasian marble, Parian marble from Lakkoi, Proconnesian marble from the island of Marmara, an unknown marble most probably of local origin, and a variety of the so-called “greco scritto” whose provenance still remains unclear. In fact, its petrographic and geochemical features do not match those known for the classical “greco scritto” from Cap de Garde, near Annaba (Algeria)
- …
