Corey Lawrence (Former Employee)
Science and Products
Filter Total Items: 14
Data for Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects Data for Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects
Light-absorbing particles in atmospheric dust deposited on snow cover (dust-on-snow, DOS) diminish albedo and accelerate the timing and rate of snow melt. Identification of these particles and their effects are relevant to snow-radiation modeling and water-resource management. Laboratory-measured reflectance of DOS samples from the San Juan Mountains (USA) were compared with DOS mass...
Batch sorption data, respired CO2, extractable DOC, and Raman spectra collected from an incubation with microbial necromass on feldspar or amorphous aluminum hydroxide Batch sorption data, respired CO2, extractable DOC, and Raman spectra collected from an incubation with microbial necromass on feldspar or amorphous aluminum hydroxide
These datasets are from an incubation experiment with a combination of two minerals (feldspar or amorphous aluminum hydroxide), one living species of bacteria (Escherichia coli), and one added form of C (Arthrobacter crystallopoietes necromass). We characterized the sorptive properties of the minerals with batch sorption experiments using four low molecular weight C substrates (glucose...
Filter Total Items: 34
Development of soil radiocarbon profiles in a reactive transport framework Development of soil radiocarbon profiles in a reactive transport framework
Today, there is a greater appreciation for the importance of the physical protection of carbon (C) through interactions with mineral surfaces, isolation from microbes, and the important role of transport in shaping soil properties and controlling moisture limitations on decomposition. As our paradigm for soil organic carbon (SOC) preservation changes, so too should our representation of...
Authors
Jennifer Druhan, Corey Lawrence
Soil respiration response to rainfall modulated by plant phenology in a montane meadow, East River, Colorado, USA Soil respiration response to rainfall modulated by plant phenology in a montane meadow, East River, Colorado, USA
Soil respiration is a primary component of the terrestrial carbon cycle. However, predicting the response of soil respiration to climate change remains a challenge due to the complex interactions between environmental drivers, especially plant phenology, temperature, and soil moisture. In this study, we use a 1‐D diffusion‐reaction model to calculate depth‐resolved CO2 production rates...
Authors
Mathew Winnick, Corey Lawrence, Maeve McCormick, Jennifer Druhan, Kate Maher
Integrating airborne remote sensing and field campaigns for ecology and Earth system science Integrating airborne remote sensing and field campaigns for ecology and Earth system science
In recent years, the availability of airborne imaging spectroscopy (hyperspectral) data has expanded dramatically. The high spatial and spectral resolution of these data uniquely enable spatially explicit ecological studies including species mapping, assessment of drought mortality and foliar trait distributions. However, we have barely begun to unlock the potential of these data to use...
Authors
K. Chadwick, Philip Brodrick, Kathleen Grant, Tristan Goulden, Amanda Henderson, Nicola Falco, Haruko Wainwright, Kenneth Williams, Markus Bill, Ian Breckheimer, Eoin Brodie, Heidi Steltzer, C. Williams, Benjamin Blonder, Jiancong Chen, Baptiste Dafflon, Joan Damerow, Matt Hancher, Aizah Khurram, Jack Lamb, Corey Lawrence, Maeve McCormick, John Musinsky, Samuel Pierce, Alexander Polussa, Maceo Hastings Porro, Andea Scott, Hans Wu Singh, Patrick O. Sorensen, Charuleka Varadharajan, Bizuayehu Whitney, Katharine Maher
Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects
Light-absorbing particles in atmospheric dust deposited on snow cover (dust-on-snow, DOS) diminish albedo and accelerate the timing and rate of snow melt. Identification of these particles and their effects are relevant to snow-radiation modeling and thus water-resource management. Laboratory-measured reflectance of DOS samples from the San Juan Mountains (USA) were compared with DOS...
Authors
Richard Reynolds, Harland Goldstein, Bruce Moskowitz, Raymond Kokaly, Seth Munson, Peat Solheid, George Breit, Corey Lawrence, Jeff Derry
An open source database for the synthesis of soil radiocarbon data: ISRaD version 1.0 An open source database for the synthesis of soil radiocarbon data: ISRaD version 1.0
Radiocarbon is a critical constraint on our estimates of the timescales of soil carbon cycling that can aid in identifying mechanisms of carbon stabilization and destabilization and improve the forecast of soil carbon response to management or environmental change. Despite the wealth of soil radiocarbon data that have been reported over the past 75 years, the ability to apply these data...
Authors
Corey Lawrence, Jeffrey Beem-Miller, Alison Hoyt, Grey Monroe, Carlos Sierra, Shane Stoner, Katherine Heckman, Joseph Blankinship, Susan Crow, Gavin McNichol, Susan Trumbore, Paul Levine, Olga Vinduskova, Katherine Todd-Brown, Craig Rasmussen, Caitlin Hicks Pries, Christina Schadel, Karis McFarlane, Sebastian Doetterl, Christine Hatte, Yujie He, Claire Treat, Jennifer Harden, Margaret Torn, Cristian Estop-Aragonés, Asmeret Berhe, Marco Keiluweit, Agatha Kuhnen, Erika Marin-Spiotta, Alain Plante, Aaron Thompson, Zheng Shi, Joshua Schimel, Lydia J.S. Vaughn, Sophie von Fromm, Rota Wagai
The landscape of soil carbon data: Emerging questions, synergies and databases The landscape of soil carbon data: Emerging questions, synergies and databases
Soil carbon has been measured for over a century in applications ranging from understanding biogeochemical processes in natural ecosystems to quantifying the productivity and health of managed systems. Consolidating diverse soil carbon datasets is increasingly important to maximize their value, particularly with growing anthropogenic and climate change pressures. In this progress report...
Authors
Avni Malhotra, Katherine Todd-Brown, Luke Nave, Niels Batjes, James Holmquist, Alison Hoyt, Colleen Iversen, Robert Jackson, Kate Lathja, Corey Lawrence, Olga Vinduśková, William Wieder, Matt Williams, Gustaf Hugelias, Jennifer Harden
Root-driven weathering impacts on mineral-organic associations in deep soils over pedogenic time scales Root-driven weathering impacts on mineral-organic associations in deep soils over pedogenic time scales
Plant roots are critical weathering agents in deep soils, yet the impact of resulting mineral transformations on the vast deep soil carbon (C) reservoir are largely unknown. Root-driven weathering of primary minerals may cause the formation of reactive secondary minerals, which protect mineral-organic associations (MOAs) for centuries or millennia. Conversely, root-driven weathering may...
Authors
Mariela Arredondo, Corey Lawrence, Marjorie S. Schulz, Malak Tfaily, Ravi Kukkadapu, Morris Jones, Kristin Boye, Marco Keiluweit
Mineralogy dictates the initial mechanism of microbial necromass association Mineralogy dictates the initial mechanism of microbial necromass association
Soil organic matter (SOM) improves soil fertility and mitigates disturbance related to climate and land use change. Microbial necromass (the accumulated cellular residues of microorganisms) comprises the majority of soil C, yet the formation and persistence of necromass in relation to mineralogy is poorly understood. We tested whether soil minerals had different microbial necromass...
Authors
Courtney Creamer, Andrea Foster, Corey Lawrence, Jack McFarland, Marjorie S. Schulz, Mark Waldrop
Modeling transient soil moisture limitations on microbial carbon respiration: A cost-performance comparison Modeling transient soil moisture limitations on microbial carbon respiration: A cost-performance comparison
Soil microorganisms are known to survive periods of aridity and to recover rapidly after wetting events, with the ability to transition between a dormant state in dry conditions and an active state in wet conditions. Though this dynamic behavior has been previously incorporated into soil carbon respiration modeling frameworks, a direct comparison between this active-dormant transition...
Authors
Yuchen Liu, Corey Lawrence, Mathew Winnick, Hsiao-Tieh Hsu, Katherine Maher, Jennifer Druhan
Biological and mineralogical controls over cycling of low molecular weight organic compounds along a soil chronosequence Biological and mineralogical controls over cycling of low molecular weight organic compounds along a soil chronosequence
Low molecular weight organic compounds (LMWOC) represent a small but critical component of soil organic matter (SOM) for microbial growth and metabolism. The fate of these compounds is largely under microbial control, yet outside the cell, intrinsic soil properties can also significantly influence their turnover and retention. Using a chronosequence representing 1200 ka of pedogenic...
Authors
Jack McFarland, Mark Waldrop, Daniel Strawn, Courtney Creamer, Corey Lawrence, Monica Haw
Improving understanding of soil organic matter dynamics by triangulating theories, measurements, and models Improving understanding of soil organic matter dynamics by triangulating theories, measurements, and models
Soil organic matter (SOM) turnover increasingly is conceptualized as a tension between accessibility to microorganisms and protection from decomposition via physical and chemical association with minerals in emerging soil biogeochemical theory. Yet, these components are missing from the original mathematical models of belowground carbon dynamics and remain underrepresented in more recent
Authors
Joseph Blankinship, Susan Crow, Asmeret Berhe, Jennifer Druhan, Katherine Heckman, Marco Keiluweit, Corey Lawrence, Erika Marin-Spiotta, Alain Plante, Craig Rasmussen, Christina Schadel, Joshua Schmiel, Carlos Sierra, Aaron Thomson, Rota Wagai, William Weider
Beyond clay: Towards an improved set of variables for predicting soil organic matter content Beyond clay: Towards an improved set of variables for predicting soil organic matter content
Improved quantification of the factors controlling soil organic matter (SOM) stabilization at continental to global scales is needed to inform projections of the largest actively cycling terrestrial carbon pool on Earth, and its response to environmental change. Biogeochemical models rely almost exclusively on clay content to modify rates of SOM turnover and fluxes of climate-active CO2...
Authors
Craig Rasmussen, Katherine Heckman, William Wieder, Marco Keiluweit, Corey Lawrence, Asmeret Asefaw Berhe, Joseph Blankinship, Susan Crow, Jennifer Druhan, Caitlin Hicks Pries, Erika Marin-Spiotta, Alain Plante, Christina Schadel, Joshua Schmiel, Carlos A. Sierra, Aaron Thompson, Rota Wagai
Non-USGS Publications**
Lawrence, C.R., Neff, J.C., and Farmer, G.L., 2011, The accretion of aeolian dust in soils of the San Juan Mountains, Colorado, USA: Journal of Geophysical Research, 116(F2). doi:10.1029/2010JF001899
Ballantyne, A.P., Brahney, J., Fernandez, D., Lawrence, C.R., Saros, J., and Neff, J.C., 2011, Biogeochemical response of alpine lakes to a recent increase in dust deposition in the Southwestern, US: Biogeosciences, 8, 2689-2706. doi:10.5194/bg-8-2689-2011
Lawrence, C.R., Painter, T.H., Landry, C.C., and Neff, J.C., 2010, Contemporary geochemical composition and flux of aeolian dust to the San Juan Mountains, Colorado, United States: Journal of Geophysical Research, 115, G03007, doi:10.1029/2009JG001077.
Lawrence, C.R. and Neff, J.C., 2009, The contemporary physical and chemical flux of aeolian dust: A synthesis of direct measurements of dust deposition: Chemical Geology 267: 46-63.
Lawrence, C.R., Neff, J.C. and Schimel, J.S., 2009, Does adding microbial mechanisms of decomposition improve soil organic matter models? A comparison of four models using data from a pulsed rewetting experiment: Soil Biology & Biochemistry, 41: 1923-1934.
Neff, J.C., Ballantyne, A.P., Farmer, G.L., Mahowald, N., Conroy, J.L., Landry, C.C., Overpeck, J.T., Painter, T.H., Lawrence, C.R. and Reynolds, R.L., 2008, Increasing eolian dust deposition in the Western United States linked to human activity: Nature Geoscience, 1(3): 189-195.
Painter, T.H., Barrett, A.P., Landry, C.C., Neff, J.C., Cassidy, M.P., Lawrence, C.R., McBride, K.E. and Farmer, G.L., 2007, Impact of disturbed desert soils on duration of mountain snow cover: Geophysical Research Letters, 34(12).
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 14
Data for Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects Data for Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects
Light-absorbing particles in atmospheric dust deposited on snow cover (dust-on-snow, DOS) diminish albedo and accelerate the timing and rate of snow melt. Identification of these particles and their effects are relevant to snow-radiation modeling and water-resource management. Laboratory-measured reflectance of DOS samples from the San Juan Mountains (USA) were compared with DOS mass...
Batch sorption data, respired CO2, extractable DOC, and Raman spectra collected from an incubation with microbial necromass on feldspar or amorphous aluminum hydroxide Batch sorption data, respired CO2, extractable DOC, and Raman spectra collected from an incubation with microbial necromass on feldspar or amorphous aluminum hydroxide
These datasets are from an incubation experiment with a combination of two minerals (feldspar or amorphous aluminum hydroxide), one living species of bacteria (Escherichia coli), and one added form of C (Arthrobacter crystallopoietes necromass). We characterized the sorptive properties of the minerals with batch sorption experiments using four low molecular weight C substrates (glucose...
Filter Total Items: 34
Development of soil radiocarbon profiles in a reactive transport framework Development of soil radiocarbon profiles in a reactive transport framework
Today, there is a greater appreciation for the importance of the physical protection of carbon (C) through interactions with mineral surfaces, isolation from microbes, and the important role of transport in shaping soil properties and controlling moisture limitations on decomposition. As our paradigm for soil organic carbon (SOC) preservation changes, so too should our representation of...
Authors
Jennifer Druhan, Corey Lawrence
Soil respiration response to rainfall modulated by plant phenology in a montane meadow, East River, Colorado, USA Soil respiration response to rainfall modulated by plant phenology in a montane meadow, East River, Colorado, USA
Soil respiration is a primary component of the terrestrial carbon cycle. However, predicting the response of soil respiration to climate change remains a challenge due to the complex interactions between environmental drivers, especially plant phenology, temperature, and soil moisture. In this study, we use a 1‐D diffusion‐reaction model to calculate depth‐resolved CO2 production rates...
Authors
Mathew Winnick, Corey Lawrence, Maeve McCormick, Jennifer Druhan, Kate Maher
Integrating airborne remote sensing and field campaigns for ecology and Earth system science Integrating airborne remote sensing and field campaigns for ecology and Earth system science
In recent years, the availability of airborne imaging spectroscopy (hyperspectral) data has expanded dramatically. The high spatial and spectral resolution of these data uniquely enable spatially explicit ecological studies including species mapping, assessment of drought mortality and foliar trait distributions. However, we have barely begun to unlock the potential of these data to use...
Authors
K. Chadwick, Philip Brodrick, Kathleen Grant, Tristan Goulden, Amanda Henderson, Nicola Falco, Haruko Wainwright, Kenneth Williams, Markus Bill, Ian Breckheimer, Eoin Brodie, Heidi Steltzer, C. Williams, Benjamin Blonder, Jiancong Chen, Baptiste Dafflon, Joan Damerow, Matt Hancher, Aizah Khurram, Jack Lamb, Corey Lawrence, Maeve McCormick, John Musinsky, Samuel Pierce, Alexander Polussa, Maceo Hastings Porro, Andea Scott, Hans Wu Singh, Patrick O. Sorensen, Charuleka Varadharajan, Bizuayehu Whitney, Katharine Maher
Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects Dust deposited on snow cover in the San Juan Mountains, Colorado, 2011-2016: Compositional variability bearing on snow-melt effects
Light-absorbing particles in atmospheric dust deposited on snow cover (dust-on-snow, DOS) diminish albedo and accelerate the timing and rate of snow melt. Identification of these particles and their effects are relevant to snow-radiation modeling and thus water-resource management. Laboratory-measured reflectance of DOS samples from the San Juan Mountains (USA) were compared with DOS...
Authors
Richard Reynolds, Harland Goldstein, Bruce Moskowitz, Raymond Kokaly, Seth Munson, Peat Solheid, George Breit, Corey Lawrence, Jeff Derry
An open source database for the synthesis of soil radiocarbon data: ISRaD version 1.0 An open source database for the synthesis of soil radiocarbon data: ISRaD version 1.0
Radiocarbon is a critical constraint on our estimates of the timescales of soil carbon cycling that can aid in identifying mechanisms of carbon stabilization and destabilization and improve the forecast of soil carbon response to management or environmental change. Despite the wealth of soil radiocarbon data that have been reported over the past 75 years, the ability to apply these data...
Authors
Corey Lawrence, Jeffrey Beem-Miller, Alison Hoyt, Grey Monroe, Carlos Sierra, Shane Stoner, Katherine Heckman, Joseph Blankinship, Susan Crow, Gavin McNichol, Susan Trumbore, Paul Levine, Olga Vinduskova, Katherine Todd-Brown, Craig Rasmussen, Caitlin Hicks Pries, Christina Schadel, Karis McFarlane, Sebastian Doetterl, Christine Hatte, Yujie He, Claire Treat, Jennifer Harden, Margaret Torn, Cristian Estop-Aragonés, Asmeret Berhe, Marco Keiluweit, Agatha Kuhnen, Erika Marin-Spiotta, Alain Plante, Aaron Thompson, Zheng Shi, Joshua Schimel, Lydia J.S. Vaughn, Sophie von Fromm, Rota Wagai
The landscape of soil carbon data: Emerging questions, synergies and databases The landscape of soil carbon data: Emerging questions, synergies and databases
Soil carbon has been measured for over a century in applications ranging from understanding biogeochemical processes in natural ecosystems to quantifying the productivity and health of managed systems. Consolidating diverse soil carbon datasets is increasingly important to maximize their value, particularly with growing anthropogenic and climate change pressures. In this progress report...
Authors
Avni Malhotra, Katherine Todd-Brown, Luke Nave, Niels Batjes, James Holmquist, Alison Hoyt, Colleen Iversen, Robert Jackson, Kate Lathja, Corey Lawrence, Olga Vinduśková, William Wieder, Matt Williams, Gustaf Hugelias, Jennifer Harden
Root-driven weathering impacts on mineral-organic associations in deep soils over pedogenic time scales Root-driven weathering impacts on mineral-organic associations in deep soils over pedogenic time scales
Plant roots are critical weathering agents in deep soils, yet the impact of resulting mineral transformations on the vast deep soil carbon (C) reservoir are largely unknown. Root-driven weathering of primary minerals may cause the formation of reactive secondary minerals, which protect mineral-organic associations (MOAs) for centuries or millennia. Conversely, root-driven weathering may...
Authors
Mariela Arredondo, Corey Lawrence, Marjorie S. Schulz, Malak Tfaily, Ravi Kukkadapu, Morris Jones, Kristin Boye, Marco Keiluweit
Mineralogy dictates the initial mechanism of microbial necromass association Mineralogy dictates the initial mechanism of microbial necromass association
Soil organic matter (SOM) improves soil fertility and mitigates disturbance related to climate and land use change. Microbial necromass (the accumulated cellular residues of microorganisms) comprises the majority of soil C, yet the formation and persistence of necromass in relation to mineralogy is poorly understood. We tested whether soil minerals had different microbial necromass...
Authors
Courtney Creamer, Andrea Foster, Corey Lawrence, Jack McFarland, Marjorie S. Schulz, Mark Waldrop
Modeling transient soil moisture limitations on microbial carbon respiration: A cost-performance comparison Modeling transient soil moisture limitations on microbial carbon respiration: A cost-performance comparison
Soil microorganisms are known to survive periods of aridity and to recover rapidly after wetting events, with the ability to transition between a dormant state in dry conditions and an active state in wet conditions. Though this dynamic behavior has been previously incorporated into soil carbon respiration modeling frameworks, a direct comparison between this active-dormant transition...
Authors
Yuchen Liu, Corey Lawrence, Mathew Winnick, Hsiao-Tieh Hsu, Katherine Maher, Jennifer Druhan
Biological and mineralogical controls over cycling of low molecular weight organic compounds along a soil chronosequence Biological and mineralogical controls over cycling of low molecular weight organic compounds along a soil chronosequence
Low molecular weight organic compounds (LMWOC) represent a small but critical component of soil organic matter (SOM) for microbial growth and metabolism. The fate of these compounds is largely under microbial control, yet outside the cell, intrinsic soil properties can also significantly influence their turnover and retention. Using a chronosequence representing 1200 ka of pedogenic...
Authors
Jack McFarland, Mark Waldrop, Daniel Strawn, Courtney Creamer, Corey Lawrence, Monica Haw
Improving understanding of soil organic matter dynamics by triangulating theories, measurements, and models Improving understanding of soil organic matter dynamics by triangulating theories, measurements, and models
Soil organic matter (SOM) turnover increasingly is conceptualized as a tension between accessibility to microorganisms and protection from decomposition via physical and chemical association with minerals in emerging soil biogeochemical theory. Yet, these components are missing from the original mathematical models of belowground carbon dynamics and remain underrepresented in more recent
Authors
Joseph Blankinship, Susan Crow, Asmeret Berhe, Jennifer Druhan, Katherine Heckman, Marco Keiluweit, Corey Lawrence, Erika Marin-Spiotta, Alain Plante, Craig Rasmussen, Christina Schadel, Joshua Schmiel, Carlos Sierra, Aaron Thomson, Rota Wagai, William Weider
Beyond clay: Towards an improved set of variables for predicting soil organic matter content Beyond clay: Towards an improved set of variables for predicting soil organic matter content
Improved quantification of the factors controlling soil organic matter (SOM) stabilization at continental to global scales is needed to inform projections of the largest actively cycling terrestrial carbon pool on Earth, and its response to environmental change. Biogeochemical models rely almost exclusively on clay content to modify rates of SOM turnover and fluxes of climate-active CO2...
Authors
Craig Rasmussen, Katherine Heckman, William Wieder, Marco Keiluweit, Corey Lawrence, Asmeret Asefaw Berhe, Joseph Blankinship, Susan Crow, Jennifer Druhan, Caitlin Hicks Pries, Erika Marin-Spiotta, Alain Plante, Christina Schadel, Joshua Schmiel, Carlos A. Sierra, Aaron Thompson, Rota Wagai
Non-USGS Publications**
Lawrence, C.R., Neff, J.C., and Farmer, G.L., 2011, The accretion of aeolian dust in soils of the San Juan Mountains, Colorado, USA: Journal of Geophysical Research, 116(F2). doi:10.1029/2010JF001899
Ballantyne, A.P., Brahney, J., Fernandez, D., Lawrence, C.R., Saros, J., and Neff, J.C., 2011, Biogeochemical response of alpine lakes to a recent increase in dust deposition in the Southwestern, US: Biogeosciences, 8, 2689-2706. doi:10.5194/bg-8-2689-2011
Lawrence, C.R., Painter, T.H., Landry, C.C., and Neff, J.C., 2010, Contemporary geochemical composition and flux of aeolian dust to the San Juan Mountains, Colorado, United States: Journal of Geophysical Research, 115, G03007, doi:10.1029/2009JG001077.
Lawrence, C.R. and Neff, J.C., 2009, The contemporary physical and chemical flux of aeolian dust: A synthesis of direct measurements of dust deposition: Chemical Geology 267: 46-63.
Lawrence, C.R., Neff, J.C. and Schimel, J.S., 2009, Does adding microbial mechanisms of decomposition improve soil organic matter models? A comparison of four models using data from a pulsed rewetting experiment: Soil Biology & Biochemistry, 41: 1923-1934.
Neff, J.C., Ballantyne, A.P., Farmer, G.L., Mahowald, N., Conroy, J.L., Landry, C.C., Overpeck, J.T., Painter, T.H., Lawrence, C.R. and Reynolds, R.L., 2008, Increasing eolian dust deposition in the Western United States linked to human activity: Nature Geoscience, 1(3): 189-195.
Painter, T.H., Barrett, A.P., Landry, C.C., Neff, J.C., Cassidy, M.P., Lawrence, C.R., McBride, K.E. and Farmer, G.L., 2007, Impact of disturbed desert soils on duration of mountain snow cover: Geophysical Research Letters, 34(12).
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.