1,720,979 research outputs found
New records of hexanchiform sharks (Elasmobranchii: Neoselachii) from the Late Cretaceous of Antarctica with comments on previous reports and described taxa
No full textSharks are virtually absent from coastal Antarctica since the Late Eocene glaciations, but this group exhibited a notable austral diversity during the Cretaceous and Paleogene. Several species have already been described from the Aptian-Eocene successions of the Larsen Basin exposed in the James Ross Island area (northern Antarctic Peninsula) and the predominantly deep-water Hexanchiformes have a record that, although still rare, has been continually increased. Four species of this group are currently known from that basin: Notidanodon pectinatus, Xampylodon dentatus, Rolfodon thompsoni, and Rolfodon tatere. Such records are especially concentrated in the Gamma Member of the Snow Hill Island Formation (or Herbert Sound Member of Santa Marta Formation), on James Ross Island. Here we described four teeth assigned to X. dentatus and one identified as R. tatere from upper Campanian sections of James Ross Island, highlighting the nomenclatural changes that led to the definition of Xampylodon and Rolfodon. Some specimens of X. dentatus presented here are considerably more complete or represent teeth of different positions than most previous records. The material assigned to R. tatere represents the oldest record of this species in the world, extending its time range by more than 10 million years.Fil: dos Santos, Rodolfo Otávio. Universidade de Sao Paulo; BrasilFil: Riff, Douglas. No especifíca;Fil: Rodriguez Amenabar, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; ArgentinaFil: Rodriguez Cabral Ramos, Renato. Universidade Federal do Rio de Janeiro; BrasilFil: Fernandes Rodrigues, Igor. Universidade Federal do Rio de Janeiro; BrasilFil: Scheffler, Sandro Marcelo. Universidade Federal do Rio de Janeiro; BrasilFil: Araújo Carvalho, Marcelo. Universidade Federal do Rio de Janeiro; Brasi
A paleontologia no estado do mato grosso do sul: Fósseis e afloramentos conhecidos
No full textO conhecimento sobre o registro fossilífero no estado do Mato Grosso do Sul ainda é muito incipiente, apesar das primeiras citações de fósseis terem ocorrido na segunda metade do século XIX. A área que concentra o maior número de trabalhos paleontológicos é a região das Morrarias do Urucum, Município de Corumbá, devido ao interesse comercial nos depósitos de ferro, manganês e calcário dos grupos Jacadigo e Corumbá. Outras unidades geológicas ricamente fossilíferas em outros estados, quase não apresentam fósseis no Mato Grosso do Sul. Esta ausência de fósseis, no entanto, não reflete a realidade do registro e provavelmente é fruto do pequeno número de pesquisadores que trabalharam ou estão trabalhando no estado e da escassez de cursos de Geologia e Paleontologia nas instituições de ensino superior. Com intuito de facilitar e incentivar as pesquisas envolvendo material fóssil no estado foi realizado este levantamento paleontológico que apresenta os fósseis e as localidades fossíliferas conhecidas no Mato Grosso do Sul, envolvendo um registro estratigráfico do Neo-Proterozóico até quase o presente
Os Crinoidea do afloramento Rio Caniú (Devoniano, formação Ponta Grossa), no Estado do Paraná
Get PDFOrientador: Arno BlankensteynCoorientador: Robson Tadeu BolzonMonografia (Bacharelado) - Universidade Federal do Paraná. Setor de Ciencias Biológicas. Curso de Graduaçao em Ciencias Biológica
A PALEONTOLOGIA NO ESTADO DO MATO GROSSO DO SUL: FÓSSEIS E AFLORAMENTOS CONHECIDOS
No full textO conhecimento sobre o registro fossilífero no estado do Mato Grosso do Sul ainda é muito incipiente, apesar das primeiras citações de fósseis terem ocorrido na segunda metade do século XIX. A área que concentra o maior número de trabalhos paleontológicos é a região das Morrarias do Urucum, Município de Corumbá, devido ao interesse comercial nos depósitos de ferro, manganês e calcário dos grupos Jacadigo e Corumbá. Outras unidades geológicas ricamente fossilíferas em outros estados, quase não apresentam fósseis no Mato Grosso do Sul. Esta ausência de fósseis, no entanto, não reflete a realidade do registro e provavelmente é fruto do pequeno número de pesquisadores que trabalharam ou estão trabalhando no estado e da escassez de cursos de Geologia e Paleontologia nas instituições de ensino superior. Com intuito de facilitar e incentivar as pesquisas envolvendo material fóssil no estado foi realizado este levantamento paleontológico que apresenta os fósseis e as localidades fossíliferas conhecidas no Mato Grosso do Sul, envolvendo um registro estratigráfico do Neo-Proterozóico até quase o presente
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
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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