Institution
United States Geological Survey
Government•Reston, Virginia, United States•
About: United States Geological Survey is a government organization based out in Reston, Virginia, United States. It is known for research contribution in the topics: Population & Groundwater. The organization has 17899 authors who have published 51097 publications receiving 2479125 citations. The organization is also known as: USGS & US Geological Survey.
Topics: Population, Groundwater, Volcano, Aquifer, Sediment
Papers published on a yearly basis
Papers
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United States Forest Service1, National Park Service2, University of California, Davis3, Cornell University4, University of Washington5, University of Notre Dame6, University of North Carolina at Chapel Hill7, University of Wisconsin–Extension8, United States Geological Survey9, University of Maryland, College Park10, Wisconsin Department of Natural Resources11, State University of New York System12, University of Alaska Fairbanks13, Academy of Natural Sciences of Drexel University14, United States Environmental Protection Agency15
TL;DR: In this article, the authors describe the two interwoven paths by which citizen science can improve conservation efforts, natural resource management, and environmental protection, and describe the investments needed to create a citizen science program.
646 citations
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TL;DR: In this paper, a semianalytical particle tracking method was developed for use with velocities generated from block centered finite-difference ground-water flow models, based on the assumption that each directional velocity component varies linearly within a grid cell in its own coordinate directions.
Abstract: A semianalytical particle tracking method was developed for use with velocities generated from block centered finite-difference ground-water flow models. The method is based on the assumption that each directional velocity component varies linearly within a grid cell in its own coordinate directions. This assumption allows an analytical expression to be obtained describing the flow path within an individual grid cell. Given the initial position of a particle anywhere in a cell, the coordinates of any other point along its path line within the cell, and the time of travel between them, can be computed directly. For steady-state systems, the exit point for a particle entering a cell at any arbitrary location can be computed in a single step. By following the particle as it moves from cell to cell, this method can be used to trace the path of a particle through any multidimensional flow field generated from a block-centered finite-difference flow model.
645 citations
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644 citations
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United States Naval Research Laboratory1, Brookhaven National Laboratory2, Space Sciences Laboratory3, Kingsborough Community College4, University of Münster5, Michigan State University6, Osaka University7, Jet Propulsion Laboratory8, Lawrence Livermore National Laboratory9, Kobe University10, European Synchrotron Radiation Facility11, Washington University in St. Louis12, University of Chicago13, École normale supérieure de Lyon14, University of New Mexico15, Kyushu University16, University of Tokyo17, University of Washington18, Lawrence Berkeley National Laboratory19, University of Jena20, University of Hawaii21, American Museum of Natural History22, Case Western Reserve University23, University of Hyogo24, United States Geological Survey25, Imperial College London26, State University of New York System27, Open University28, Stanford University29
TL;DR: The bulk of the comet 81P/Wild 2 samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger ferromagnesian silicates, Fe-Ni sulfides,Fe-Ni metal, and accessory phases.
Abstract: The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.
644 citations
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TL;DR: In this paper, a review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hypheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to watershed scale.
Abstract: Fifty years of hyporheic zone research have shown the important role played by the hyporheic zone as an interface between groundwater and surface waters. However, it is only in the last two decades that what began as an empirical science has become a mechanistic science devoted to modeling studies of the complex fluid dynamical and biogeochemical mechanisms occurring in the hyporheic zone. These efforts have led to the picture of surface-subsurface water interactions as regulators of the form and function of fluvial ecosystems. Rather than being isolated systems, surface water bodies continuously interact with the subsurface. Exploration of hyporheic zone processes has led to a new appreciation of their wide reaching consequences for water quality and stream ecology. Modern research aims toward a unified approach, in which processes occurring in the hyporheic zone are key elements for the appreciation, management, and restoration of the whole river environment. In this unifying context, this review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hyporheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to the watershed scale. The implications of these processes for stream biogeochemistry and ecology are also discussed.
644 citations
Authors
Showing all 18026 results
Name | H-index | Papers | Citations |
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Derek R. Lovley | 168 | 582 | 95315 |
Steven Williams | 144 | 1375 | 86712 |
Thomas J. Smith | 140 | 1775 | 113919 |
Jillian F. Banfield | 127 | 562 | 60687 |
Kurunthachalam Kannan | 126 | 820 | 59886 |
J. D. Hansen | 122 | 975 | 76198 |
John P. Giesy | 114 | 1162 | 62790 |
David Pollard | 108 | 438 | 39550 |
Alan Cooper | 108 | 746 | 45772 |
Gordon E. Brown | 100 | 454 | 32152 |
Gerald Schubert | 98 | 614 | 34505 |
Peng Li | 95 | 1548 | 45198 |
Vipin Kumar | 95 | 614 | 59034 |
Susan E. Trumbore | 95 | 337 | 34844 |
Alfred S. McEwen | 92 | 624 | 28730 |