1,720,957 research outputs found
Phylomitogenomics provides new perspectives on the Euphasmatodea radiation (Insecta: Phasmatodea)
Full text linkPhasmatodea species diversity lies almost entirely within its suborder Euphasmatodea, which exhibits a pantropical distribution and is considered to derive from a recent and rapid evolutionary radiation. To shed light on Euphasmatodea origins and diversification, we assembled the mitogenomes of 17 species from transcriptomic sequencing data and analysed them along with 22 already available Phasmatodea mitogenomes and 33 mitogenomes representing most of the Polyneoptera lineages. Maximum Likelihood and Bayesian Inference approaches retrieved consistent topologies, both showing the widespread conflict between phylogenetic approaches and traditional systematics. We performed a divergence time analysis leveraging ten fossil specimens representative of most polyneopteran lineages: the time tree obtained supports an older radiation of the clade with respect to previous hypotheses. Euphasmatodea diversification is inferred to have started ~ 187 million years ago, suggesting that the Triassic-Jurassic mass extinction and the breakup of Pangea could have contributed to the process. We also investigated Euphasmatodea mitogenomes patterns of dN, dS and dN/dS ratio throughout our time-tree, trying to characterize the selective regime which may have shaped the clade evolution
Macroevolutionary Analyses Provide New Evidence of Phasmid Wings Evolution as a Reversible Process
Full text linkThe concept that complex ancestral traits can never be recovered after their loss is still widely accepted, despite phylogenetic and molecular approaches suggest instances where phenotypes may have been lost throughout the evolutionary history of a clade and subsequently reverted back in derived lineages. One of the first and most notable examples of such a process is wing evolution in phasmids; this polyneopteran order of insects, which comprises stick and leaf insects, has played a central role in initiating a long-standing debate on the topic. In this study, a novel and comprehensive time tree including over 300 Phasmatodea species is used as a framework for investigating wing evolutionary patterns in the clade. Despite accounting for several possible biases and sources of uncertainty, macroevolutionary analyses consistently revealed multiple reversals to winged states taking place after their loss, and reversibility is coupled with higher species diversification rates. Our findings support a loss of or reduction in wings that occurred in the lineage leading to the extant phasmid most recent common ancestor, and brachyptery is inferred to be an unstable state unless co-opted for nonaerodynamic adaptations. We also explored how different assumptions of wing reversals probability could impact their inference: we found that until reversals are assumed to be over 30 times more unlikely than losses, they are consistently inferred despite uncertainty in tree and model parameters. Our findings demonstrate that wing evolution is a reversible and dynamic process in phasmids and contribute to our understanding of complex trait evolution. [Dollo's law; Phasmatodea; phylogenetic comparative methods; polyneoptera; reversals; wing.]
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
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