1,720,966 research outputs found
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
Frequência de preservação de biomateriais não mineralizados no registro fóssil de répteis mesozoicos: uma abordagem sobre pterossauros e répteis marinhos / Frequency of non-mineralized biomaterials preservation in the fossil record of Mesozoic reptiles: an approach on pterosaurs and marine reptiles
Get PDFNas últimas décadas, vários estudos encontraram preservação excepcional de diferentes biomoléculas originais em dinossauros. Porém, grupos distintos de répteis que dominaram ares, mares e oceanos na Era Mesozoica, como pterossauros, ictiossauros, mosassauros, notossauros e plesiossauros, apresentam dados escassos a respeito de achados de biomateriais não mineralizados e os que já foram identificados estão dispersos na literatura, associando a ideia das descobertas a fenômenos isolados. Este trabalho apresenta uma revisão da literatura publicada nas últimas duas décadas, a fim de compreender melhor a frequência dos achados reivindicados de biomateriais não mineralizados em fósseis de répteis do clado Pterosauria e de répteis marinhos do clado Lepidosauromorpha da Era Mesozóica, frequentemente confundidos com dinossauros pelo imaginário popular. Os resultados identificaram 3 estudos descrevendo materiais orgânicos preservados para representantes de Pterosauria. Para répteis marinhos do clado Lepidosauromorpha, foram encontrados 8 estudos com achados distribuídos entre Ichthyosauria, Mosasauria, Nothosauroidea e Plesiosauria. Em geral, os dados para tais grupos não se mostraram geográfica e taxonomicamente abrangentes nas rochas mesozóicas. No entanto, acredita-se que a frequência é subnotificada, e a partir do surgimento de novas tecnologias, a previsão é de que a bioquímica fóssil seja caracterizada em maior quantidade
Lesson Plan Proposal on Molecular Paleontology for insertion in the discipline of Paleontology of undergraduate courses in Biological Sciences
No full textMolecular Paleontology has not been included in the syllabus of the discipline of Paleontology in undergraduate courses in Biological Sciences. However, if inserted in the discipline's Teaching Plan, Molecular Paleontology could bring future biologists closer to Paleobiology, a field of research that is practically unexplored in Brazil. Therefore, it is considered that Molecular Paleontology is relevant for composing Lesson Plans that consider emerging research fields to be explored by future biologists. Thus, the objective of this work was to elaborate a Lesson Plan, with introductory contents of Molecular Paleontology, and to propose it as a model to be inserted in the discipline of Paleontology of undergraduate courses in Biological Sciences. The final proposal of the Lesson Plan brought an already anticipated synthesis of paleomolecular knowledge, which can streamline educational action and minimize the difficulties that arise during the research and the choice of material by the teacher. In addition, the instrument is applicable in just two class hours. It is believed that, in the way the educational product was thought, it could enrich the teaching pedagogical practices, expanding the baggage of the teacher's didactic-pedagogical contents and instrumentals and promoting the formation of a new generation of professionals more qualified to deal with scientific issues emergin
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
Current perspectives on non-mineralized soft tissues in non-avian dinosaur fossils
Get PDFDespite extensive published literature, skepticism about the claim of original soft tissues persists and the subject remains controversial. Data regarding the frequency of soft tissue findings are still scarse and those that have already been systematized are dispersed in the literature, which leads the idea of soft tissues to be associated with isolated phenomena. This article presents a review of the relevant literature, published in the last 50 years, in order to better understand the frequency of non-mineralized soft tissue findings in non-avian dinosaur fossils, and the time limits for expected survival of these biomolecules. The results identified 52 papers describing preserved organic material, considered geologically, geographically and taxonomically comprehensive. Still, it is believed that this frequency is underreported due to the current resistance in accepting these findings as being from organic remnants. The prediction is that acquisition of new technologies will turn such findings as the norm and not the exception
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
Exceptional Preservation of Non-Mineralized Biomaterials in Fossils of the Avialae Clade
Get PDFThousands of primitive and diverse fossils birds from Mesozoic and Cenozoic have been discovered around the world. Among these,
hundreds of studies have found exceptional preservation of mineralized biomaterials, allowing to expand the knowledge about the ecology and Evolution of birds. However, the Avialae clade presents scarce data regarding non-mineralized biomaterials, and those that have already been identified are dispersed in the scientific publications, associating the idea of the findings with isolated phenomena. This paper presents a review of the literature published in the last two decades, in order to better understand the frequency of nonmineralized biomaterials findings in fossils of the Avialae clade. 12 articles describing original biocomponents for representatives of Anchiornithinae, Confuciusornithidae, Enantiornithes and Euornithes were found. Among these, the molecules of proteins (50%) and melanins (41.7%) showed higher frequency of findings. In general, although the data for the groups were not shown to be taxonomically comprehensive, there was a wide geographic distribution across the globe regarding original biochemicals in mesozoic and cenozoic rocks. However, it is believed that the frequency is underreported and, from the emergence of new technologies, the forecast is that more organic biomaterials will be identified in the fossils
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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