1,720,976 research outputs found
Museum ‘dark data’ show variable impacts on deep-time biogeographic and evolutionary history
No full textThe age of digitally accessible datasets has transformed palaeontology, enabling previously impossible macroevolutionary insights. However, a substantial reservoir of generally inaccessible ‘dark data’ resides within museum collections, which may alter our understanding of ancient groups and their ecological and evolutionary history. We demonstrate how the addition of data held exclusively in museums impacts our macroevolutionary understanding of an entire taxonomic group, using a dataset of Palaeozoic echinoids containing the majority of museum occurrences for the clade. We find that museum ‘dark data’ shows clear differences in composition compared to data available in the published literature and strongly impacts biogeographic patterns, increasing the average geographic range size of taxa by 35%. Global model results assessing drivers of diversity are also significantly affected by the addition of museum-only data. Conversely, ‘dark data’ have a more limited impact on the temporal ranges of taxa or estimates of overall diversity and are impacted by similar socio-geographic biases as the published record. These findings show that unpublished museum data are necessary to obtain a complete understanding of macroevolutionary patterns in deep-time, illustrating the importance of the collection, curation, digitization and continued care of ‘dark data’ in the age of ‘Big Data’ in palaeobiology
Taphonomic controls on a multi‐element marine skeletal fossil record
No full textAnimals with multi-element skeletons, including the vertebrates, echinoderms and arthropods, are some of the most biodiverse and ecologically important animal groups. Understanding the relative impact of the myriad geological and biological factors which impact on the quality of multi-element skeletal fossils is thus crucial for disentangling perceived changes in biodiversity through time and shedding light on gaps in the fossil record. We have characterized the specimen-level taphonomic history of virtually the entire Palaeozoic fossil record of echinoids, the class of echinoderms which includes the living sea urchins. We find that the majority of this fossil record consists of disarticulated skeletal elements and as preservational quality increases, so does the proportion of specimens which can be identified with higher taxonomic precision. We then assessed the relative impacts of multiple geological and biological factors on our specimen quality, identifying that fine-grained host matrix, as well as siliciclastic lithology are the biggest factors in determining quality of fossil echinoid preservation, while aspects intrinsic to specific taxonomic groups also play a role. Differential sampling of the fossil record seems to play little role in influencing the distribution of taphonomic grades, and fluctuations in the North American record of siliciclastic rocks are positively correlated with fluctuations in taphonomic grades. Our results highlight that the factors controlling the animal macrofossil record are varied, and that the interplay between these variables, taphonomic grade, and taxonomic precision impacts on our ability to use the fossil record to understand macroevolution
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
