1,721,999 research outputs found
Changes of North Atlantic plate motion in early Paleogene driven by Icelandic plume:Insights from kinematic and stratigraphic constraints
Full text linkMantle convection is a fundamental process that shapes the Earth's surface by providing the driving and resisting forces for horizontal motion of tectonic plates, as well as for inducing non-isostatic vertical motion commonly termed “dynamic topography”. Growing observational constraints of past plate motion and dynamic topography have led to better understanding of the history of surface expression induced by mantle flow. Often these two surface motion signals are studied separately. However, the existence of a thin, mechanically weak asthenosphere allows geodynamicists to link horizontal and vertical motion changes together via mantle flow properties in the context of pressure-driven Poiseuille-type flow. In this paper, we utilize publicly available geologic and geophysical datasets to study early Paleogene plate kinematics and spatiotemporal evolution of dynamic topography in the North Atlantic region. We find that the North America (NAM) and Greenland (GRN) plates experienced a rapid kinematic change around late Paleocene–early Eocene, coinciding with episodes of surface uplift inferred from stage-resolution stratigraphic information around the North Atlantic, Labrador Sea and Baffin Bay. We quantitatively tie these surface motion signals together to underlying asthenospheric flow processes by estimating torque variations on NAM and GRN. These are parameterized in terms of reconstructed kinematic changes as well as predicted Poiseuille-type flow induced by increasing Icelandic plume flux and speedup of Farallon slab. Our analysis indicates (1) that the torque-change associated with the Icelandic plume flux closely resembles the ones inferred from kinematic reconstructions, and (2) that the inclusion of slab effects does not modify significantly such a scenario. Our findings shed light on the role of asthenospheric channelized flow generated by the Icelandic plume in influencing the early Paleogene North Atlantic surface dynamics
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
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