1,721,296 research outputs found
Nonlinearity and Complexity in Gravel Bed Dynamics
No full text1 online resource (PDF, 27 pages, includes illustrations)Singh, Arvind; Lanzoni, Stefano; Foufoula-Georgiou, Efi. (2009). Nonlinearity and Complexity in Gravel Bed Dynamics. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/180096
Gap-filled USGS sensor data for nitrate, discharge and temperature for selected sites in Iowa, U.S.A.
No full textThe raw data used in this project are available through the United States Geological Survey National Water Information System data portal. More information about this project and the associated files can be found in the Readme.National Science Foundation under Grant EAR-1415206 Science, Engineering and Education for Sustainability (SEES) Fellows to A.T.H.: SEES Fellows: Leveraging the waterscape to increase agricultural landscape sustainability. Donor of American Chemical Society Petroleum Research Fund to A.S.Singh, Arvind; Hansen, Amy, T. (2018). Gap-filled USGS sensor data for nitrate, discharge and temperature for selected sites in Iowa, U.S.A.. Retrieved from the Data Repository for the University of Minnesota (DRUM), https://doi.org/10.13020/D6T106
Revisiting N2 fixation in the North Atlantic Ocean: Significance of deviations from the Redfield Ratio, atmospheric deposition and climate variability
No full textThe average oceanic nitrate-to-phosphate molar ratio (NO3?:PO43??16:1, referred to as the Redfield Ratio) in subsurface waters, which is similar to the average ratio of particulate nitrogen (N)-to-phosphorus (P) in phytoplankton, is the cornerstone in calculating geochemical estimates of N2 fixation and denitrification rates. Any deviations from this canonical Redfield Ratio in intermediate ocean waters, expressed as N* (a measure of NO3? in excess or deficit of 16×PO43?), provides an integrated estimate of net N fluxes into and out of the ocean. In well-oxygenated ocean basins such as the North Atlantic Ocean, N* estimates are usually positive and can be used to infer that rates of N2 fixation exceed rates of denitrification. We use this approach to estimate N2 fixation over the last two decades (1988–2009) based on data collected at the Bermuda Atlantic Time-series Study (BATS) site in the North Atlantic Ocean near Bermuda. Our results indicate that interpretation of the N* tracer as an estimate of N2 fixation should be undertaken with caution, as N2 fixation is not the only process that results in a positive N* estimate. The impacts of a locally variable nitrogen-to-phosphorus ratio, relative to the fixed Redfield Ratio, in the suspended particulate matter as well as in the subsurface water nutrients and atmospheric N deposition on N* variability were examined. Furthermore, we explored the role of climate modes (i.e., North Atlantic Oscillation and Arctic Oscillation) on N* variability. We found that N* in the subsurface waters was significantly affected by these factors and hence previous estimates of N2 fixation using this technique might have been substantially overestimated. Our revised estimate of N2 fixation in the North Atlantic Ocean (0°N–50°N, 20°W–80°W) is 12.2±0.9×1011 mol N yr?1, and based on long-term BATS data provides better constraints than both earlier indirect and direct estimates N2 fixation
A Theoretical Framework for Interpreting and Quantifying the Sampling Time Dependence of Gravel Bedload Transport Rates
Full text link1 online resource (PDF, 23 pages, includes illustrations)Fienberg, Kurt; Singh, Arvind; Foufoula-Georgiou, Efi; Jerolmack, Doug; Marr, Jeffrey D.G.. (2009). A Theoretical Framework for Interpreting and Quantifying the Sampling Time Dependence of Gravel Bedload Transport Rates. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/180094
On the influence of gravel bed dynamics on velocity power spectra
Full text link1 online resource (PDF, 15 pages, includes illustrations)Singh, Arvind; Porté-Agel, Fernando; Foufoula-Georgiou, Efi. (2009). On the influence of gravel bed dynamics on velocity power spectra. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/180103
Experimental evidence for statistical scaling and intermittency in sediment transport rates
Full text link1 online resource (PDF, 48 pages, includes illustrations)Singh, Arvind; Fienberg, Kurt; Jerolmack, Douglas J.; Marr, Jeffrey D.G.; Foufoula-Georgiou, Efi. (2009). Experimental evidence for statistical scaling and intermittency in sediment transport rates. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/180095
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
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