1,721,006 research outputs found
A new Metapolygnathus platform conodont species and its implications for Upper Carnian global correlations
Full text linkA rich conodont fauna from two Neotethyan sections, Pizzo Mondello (western Sicily, Italy) and Pignola 2 sections (southern Apennines, Italy) includes conodonts described herein as a new species. Metapolygnathus praecommunisti sp. nov. is transitional between Paragondolella noah and Metapolygnathus communisti. The genus Metapolygnathus (in− cluding M. praecommunisti) is now characterised by posterior prolongation of the keel termination, associated with a cen− trally located pit and with a weak ornamentation confined to the anterior part of the platform margins. The establishment of M. praecommunisti addresses the problems related to the origin and the peculiar, probably facies−controlled, distribu− tion of its descendant species M. communisti. Since M. praecommunisti occurs in the entire Tethys and in North America, we propose the species as a good guide fossil for global correlations, characterised by a short temporal range limited to the uppermost Tuvalian (upper Carnian). The stratigraphic occurrence of the genus Metapolygnathus is restricted to the Tuvalian–Lacian (upper Carnian–lower Norian), excluding its presence in the Julian substage (lower Carnian)
Precast Concrete Industrial Portal Frames Subjected to Simulated Fire
No full textPrecast concrete industrial frames made with tall columns cantilevering from their base and with simply supported prestressed horizontal beam/roof members, widely diffused in Europe and abroad, host most of the industrial activities of the continent, including the many characterised by high fire risk due to production or handling of materials/products having high combustion potential. The typical structural checks under fire action of such structures consists in a simplified cross-section analysis under the action of nominal temperature curves over time. However, this sort of analysis neglects the thermal-mechanical deformation induced by the exposure to fires of the structural elements. This contribution may become critical if considering the beam-column portal sub-assemblies, especially whenever peripheral columns are provided with infill walls. In this case, unlike central columns exposed to somehow uniform fire at all sides, a relevant differential thermal gradient occurs in the slender element, bringing it to large outward deformation activating 2nd order effects and coming into geometrical conflict with the beam, possibly leading to the collapse of the beam due to loss of support. This article presents a case study based on a real precast industrial building carried out employing a full Fire Safety Engineering workflow: (a) realistic fire scenarios encompassing different fire load distributions are simulated by computational fluid dynamics based on experimental curves of rate of heat release found in literature; (b) temperature distribution within the concrete elements was obtained with non-linear thermal analysis in variable regime; (c) strength and deformation of the concrete elements were checked with non-linear thermal-mechanical analysis based on parallel stripes in straight bending
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
Ostracods across the Permian–Triassic boundary in Western Tethys: The Bulla parastratotype (Southern Alps, Italy).
No full textAbstract. Investigation of the ostracod fauna of the parastratotype of the Permian-Triassic boundary at Bulla in the Southern Alps produced 62 species belonging to 31 genera. They are all discussed and figured. This paper presents results of the first description of ostracods from this important site. One genus, Bairdiacratia n. gen., and 13 species are new; Glyptopleurina pasinii n. sp., Knoxiella ventrospinosa n. sp., Knightina bullaensis n. sp., Bairdia ortiseiensis n. sp., B. cheni n. sp., B. (Rectobairdia) kershawi n. sp., Bairdiacratia qinglai n. gen. n. sp., B. tergilata n. gen. n. sp., Microcheilinella lata n. sp., Parabythocythere chongpani n. sp., Cavellina belleropbonella n. sp.,
C. alpina n. sp. and C. triassica n. sp. The palaeoecological analysis of each unit is produced. The unconformity-paraconformity U1 is clearly reflected in the ostracod assemblages and is marked by a drop in diversity and abundance of specimens. It was followed by a change
in the ostracod faunal composition. The Bulla Member displays maximum ostracod diversity and abundance linked with the trangressive trend reported for this period. The unconformity-paraconformity U2, at the boundary between the Bellerophon and Werfen formations (Bulla and Lower Tesero members) is the main extinction level for ostracods. The Lower Tesero, Lower Mazzin and Upper Tesero members
have very poor faunas. The lower part of the Upper Mazzin Mb. is characterized by an uneven burst of diversiry before the great period of taxonomic paucity observed during the late Griesbachian all over the world
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
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