1,721,013 research outputs found
The world atlas of rivers, estuaries, and deltas
No full textFrom the Congo and the Mekong to the Seine and the Mississippi, Earth’s rivers carve through landscapes before coursing into the world’s oceans through estuaries and deltas. Their inexorable flow carries sediment and more, acting as lifeblood for a variety of ecosystems and communities. More than any other surface feature of Earth, rivers, estuaries, and deltas are vitally important to our economic and social well-being, and our management of them often sits at the sharp edge of today’s most pressing environmental challenges. The World Atlas of Rivers, Estuaries, and Deltas takes readers on an unforgettable tour of these dynamic bodies of water, explaining how they function at each stage of their flow. Combining maps and graphics with informative essays and beautiful photos, this invaluable reference book will give you a new appreciation for the power that rivers, estuaries, and deltas wield
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
Coupled evolution of rivers and floodplains
No full textRiver-floodplains are coupled systems in which the conveyance and cycling of sediment over centuries to millennia set the morphological and sedimentological boundary conditions that control fluvial processes over shorter time periods (e.g., years to decades). Although this is well known, understanding how such processes are coupled over short and long timescales remains a significant challenge. Moreover, fluvial geomorphology as a discipline has, arguably, focused more on the study of within-channel processes and dynamics, with less attention given to how river-floodplain interactions and feedbacks control the functioning of the wider river corridor (i.e., channel-belt). Growing concern over the potential impacts of 21st century environmental change (e.g., on river morphology, flood conveyance and floodplain ecosystems) highlights a pressing need to address this knowledge gap.This study applies a physically-based morphodynamic model to investigate the coupled evolution of channel-floodplain systems. The model solves the shallow water equations for in-channel and overbank flows, together with equations representing fine and coarse sediment transport, channel migration and floodplain development. Simulations are run over time periods sufficient for the floodplain to be reworked (and hence reconstructed) by the model. Simulation results provide new insights into: (i) the relative importance of river gradient, sediment flux and bank erodibility as controls on channel migration rates; (ii) the factors that determine the mechanisms and frequency of channel cutoffs; (iii) the degree to which floodplain dynamics (e.g., floodplain reworking and construction) control both floodplain topography and river pattern; (iv) the relative importance of bedload versus suspended load in determining overall fluvial system behaviour; and (v) the challenges involved in simulating these effects using numerical models
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
Multibeam echosounding as a tool for mapping geologic features, bathymetry and modern vents, Yellowstone National Park, Wyoming
Get PDFYellowstone National Park (YNP) is a unique area for study due to the broad range of geologic and geomorphic agents that have sculpted this terrain over time. This research employed a multibeam echosounder (MBES) in Lewis Lake and Yellowstone Lake, in August 2011, to describe and interpret the geologic and geomorphic processes that have shaped Lewis Lake, as well as enhance our understanding of selected hydrothermally-active areas within Yellowstone Lake.
Since the eruption that formed the present day caldera 640,000 years ago, dozens of smaller eruptions of differing compositions have occurred. The first-ever bathymetric and acoustic backscatter map of Lewis Lake shows that the lake morphology has been shaped by at least four separate volcanic events. These include tuff, rhyolitic and pyroclastic flows that have altered the hydrothermal plumbing of the lake bed. Using this data, a timeline for the evolution of Lewis Lake has been constructed that allows the geology of the lake floor to be integrated into existing ‘onshore’ outcrop studies. MBES mapping was also used to examine three areas hydrothermally active areas of Yellowstone Lake: the Inflated Plain, Elliot’s Crater, and the Stephenson Island depression chain. These surveys yielded high-resolution bathymetric maps. Additionally, acoustic returns from the water column were used to determine the location of active degassing areas, as well as rates of gas discharge from a hydrothermal crater in the Inflated Plain, Yellowstone Lake. Using the acoustic returns in the water column, a rate of 0.72-726.6 g m-2 day-1 was calculated to be erupting from this individual sub-aqueous crater. These rates are consistent with gas discharge directly measured in other hydrothermal vents around the world. These results have shown the potential for MBES technology not only to produce high-resolution bathymetric maps, but also aid in geologic mapping as well as geohazard evaluation in subaqueous hydrothermal environments.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-08-01The student, Ronald Cash, accepted the attached license on 2015-07-21 at 16:24.The student, Ronald Cash, submitted this Thesis for approval on 2015-07-21 at 16:25.This Thesis was approved for publication on 2015-07-23 at 09:14.DSpace SAF Submission Ingestion Package generated from Vireo submission #8593 on 2015-09-29 at 15:00:55Made available in DSpace on 2015-09-29T20:50:23Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-07-23Embargo set by: Seth Robbins for item 89504
Lift date: 2017-09-29T20:50:34Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 89504 on 2017-09-30T09:15:18Z
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