1,721,086 research outputs found
Effects of topography on lofting gravity flows: Implications for the deposition of deep-water massive sands
No full textProcesses and deposits of submarine sediment density flows within the Moroccan turbidite system, offshore NW Africa
Get PDFSubmarine sediment density flows are a major process for transporting sediment from the continental shelf to the deep-ocean. Understanding submarine flow dynamics relies upon analysis of their deposits (beds) because monitoring them directly is difficult. However, it is rare to be able to correlate individual beds for long distances. This limits our understanding to ‘idealized’ models based on field data with limited lateral extent. Validation of these models requires individual beds to be mapped out. Using > 100 shallow sediment cores this thesis correlates individual beds across their depositional extent (over 2000 km), within the Late Quaternary Moroccan Turbidite System, offshore NW Africa. The vertical and spatial distributions of facies and grain size are examined in each bed to understand the dynamics of the parent flows. The height to which deposits drape up topography is used to infer flow thicknesses.Proximally, synchronous flows passed into the system from multiple disparate entry points. Earthquakes could have triggered these flows. However, it is not possible to determine if these beds were related to earthquakes, highlighting the difficulties faced extending turbidite palaeoseismology beyond the historical earthquake record.Across the central parts of the system flows are interpreted to have been relatively thin and slow moving, yet able to run out for hundreds of kilometers on slopes of < 0.02º. Current, models cannot explain how this is possible.Distally, channels develop and connect two basins. Examination of these channels reveals they are purely constructional features. Flows were able to bypass > 100 km3 of sediment through the channel axes without eroding. Channel relief was built and maintained by deposition along the channel margins and no erosion.The distribution of grain-size breaks is examined within individual beds across the entire system. Grain-size breaks between sand and mud occur almost everywhere. This is attributed to fluid mud layers bypassing intermediate grain sizes down slope. Such a process should (almost) always occur; hence this type of grain-size break should be recognized as a typical feature rather than an exception.The ability to map out individual beds over such distances provides a rare and valuable opportunity to validate models; developed from laterally restricted outcrops, laboratory experiments and theory. Results from this thesis demonstrate current models are limited and that we still have much to learn about the dynamics of submarine flows and how they transport sediment across vast swathes of the seafloor
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
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
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
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
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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