1,720,956 research outputs found
Hydrodynamics and Sediment Transport at the River-Ocean Interface: Analytical and Laboratory Investigations
No full textThesis (Ph.D.)--University of Washington, 2015This study presents a combination of numerical and analytical investigations of fluid and sediment transport mechanics through the river-ocean interface. This region is defined broadly as the region within the river that is influenced by the receiving basin--both the salinity and the oscillating and mean basin heights--as well as the portion of the river influenced by the presence of a distinct fluvial buoyant water mass. More narrowly, we consider in this study an atidal salt wedge, the upstream hydraulic transition zone in the unstratified river, and the near-field river plume. The first main chapter presents a hydraulic model of the salt wedge estuary in sloped and landward-converging channels. It is found that the non-dimensionalized intrusion length is a function of the freshwater Froude number, as noted in previous studies, as well as new parameters describing the channel geometry. Further, it is found that the primary geometric influence on the intrusion length is the channel bottom slope. Comparison to field data is given indicating that the influence of nonzero bottom slope may account for the discrepancy between observation and the canonical flat estuary theory \citep{Schijf+Schonfeld1953}. Next, we link our hydraulic model of the salt wedge to a hydraulic model of the upstream river transition zone, which is influenced by the depth of the receiving basin and is not in normal flow. We add to this a parameterization of total sediment transport in the unstratified river \citep{Engelund+Hansen1967} and a newly developed hydraulic model of sediment transport in the salt wedge. The model retains the key mechanistic features of sediment transport in highly stratified estuaries and is ideal for morphodynamic applications. We find that the principle influence of the salt wedge is an increase in net deposition in the lower river and the introduction of a secondary maximum aggradation length scale in addition to the backwater length discussed in \citet{Chatanantavet_et_al2012}. Finally, we present experimental simulations of the steady state estuary and river plume. The results of the estuary experiments quantify the influence of bottom slope on the reduction of sensitivity of intrusion length to river discharge and confirm the results of the hydraulic model. The plume experiments indicate that the plume transitions to a jet-like outflow for sufficiently large values of in which the spreading rate is determined by lateral entrainment instead of the plume buoyancy and the liftoff is pushed far offshore. This transition is not gradual but rather step-like, being concentrated on one value (or a narrow band of values of) . Both this critical value of and the jet spreading rate depend crucially on the plume inflow aspect ratio. This jet-like behavior is anticipated to have crucial implications for delta progradation processes and the magnitude of sediment erosion in the lower river during flood events
Plume Soup: How a Dash of River Water Affects Washington's Coastal Ecosystem
Get PDFHorner-Devine will present research investigating the impact of river water on biological productivity in the Pacific Ocean along the Washington-Oregon coast. River water contribution is approximately 0.02% of the shelf waters, yet the effect of this small dash or river water seems to be significant. Horner-Devine will discuss the physical properties, sampling, and modeling of river plumes
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
