1,720,962 research outputs found
The Acheron dorsum on Mars. A novel interpretation of its linear depressions and a model for its evolution
No full textThe Acheron Dorsum north of Olympus Mons on Mars is a unique 800 km-long arcuate ridge apparently unrelated to other adjacent morphologies. Acheron Dorsum is crossed by deep and wide fractures (“fossae”, here referred to also as Linear Depressions or “LDs”), commonly interpreted as grabens formed by local lithosphere stress in response to endogenous mantle upwelling. We suggest an alternate view that the linear depressions may result from gravitational self-adjustment of a loose deposit similar to the Deep-Seated Gravitational Slope Deformations (DSGSD or Sackung), akind of slow mass movement well documented on Earth. Numerical simulations based on a finite difference numerical model devised for terrestrial DSGSDs reproduce the timing and position of LDs reasonably well provided that the viscosity of the viscoplastic layer is between ≈7 1015and ≈1017Pas. While rock masses typically exhibit much higher values, based on comparison with glacial examples, we find that these viscosities could be compatible to a rock–ice mixture.
This leads to the hypothesis that the rock underneath Acheron Dorsum may be highly fragmented and that ice might have been involved in its deformation. Our hypothesis could shed light on the puzzling stress pattern on Acheron Dorsum, which follows approximately the ridge, without requiring the presence of hypothetical small-scale, endogenous currents
Peculiar morphologies of coastal and subaqueous landslides deposits and their relationship to flow dynamics.
No full textSediment texture in rock avalanche deposits. Insights from field and experimental observations
No full textSedimentary structures within rock avalanche deposits have gained increasing attention in recent years, since they may provide useful information about the dynamics of such energetic events. This work then is aimed at better defining the physical processes arising during the propagation, paying particular attention to the kinetic sieving mechanism, and strengthening the assumption (widely diffused in the literature) that such a process does not occur for similar events. Specifically, after the examination of two rock avalanche deposits in Central Italy, where cuts through the fragmented deposits are accessible and illustrative of the sediment texture, a series of laboratory flume tests have been performed in order to investigate in detail the flowing process. A simplified physical model for granular agitation has been then introduced to explain how and why kinetic sieving may occur at the laboratory scale and, in the case of natural granular flows of reduced size, also at the field scale
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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