2,569 research outputs found
The Cosmic-ray Neutron Probe Method for Estimating Field Scale Soil Water Content: Advances and Applications
The need for accurate, real-time, reliable, and multi-scale soil water content (SWC) monitoring is critical for a multitude of scientific disciplines trying to understand and predict the earth’s terrestrial energy, water, and nutrient cycles. One promising technique to help meet this demand is fixed and roving cosmic-ray neutron probes (CRNP). However, the relationship between observed low-energy neutrons and SWC is affected by local soil and vegetation calibration parameters. This effect may be accounted for by a calibrated equation based on local soil type and the amount of standing biomass. However, determining the calibration parameters for this equation is labor and time intensive, thus limiting the full potential of the roving CRNP in large surveys and long transects, or its use in novel environments. In this work, our objective is to develop and test the accuracy of using globally available datasets (clay weight percent, soil bulk density, and soil organic carbon) to support the operability of the CRNP. Here, we develop a 1 km product of soil lattice water over the CONtinental United States (CONUS) using a database of in-situ calibration samples and globally available soil taxonomy and soil texture data. We then test the accuracy of the global dataset in the CONUS using comparisons of 61 in-situ samples of clay percent (RMSE = 5.45 wt. %, R2 = 0.68), soil bulk density (RMSE = 0.173 g/cm3, R2 = 0.203), and soil organic carbon (RMSE = 1.47 wt. %, R2 = 0.175). In addition, we conduct an uncertainty analysis of the global soil calibration parameters using a Monte Carlo error propagation analysis (maximum RSME ~0.035 cm3/cm3 at a SWC = 0.40 cm3/cm3). Fast growing crops (i.e. maize and soybeans) contribute to the CRNP signal primarily through the water within their biomass and this signal must be minimized for soil moisture retrieval. This was done by using a vegetation index derived from MODIS imagery as a proxy for standing wet biomass (RMSE \u3c 1 kg/m2). Lastly, we make recommendations to the design and validation of future roving CRNP experiments.
Advisor: Trenton E. Fran
The Cosmic-ray Neutron Probe Method for Estimating Field Scale Soil Water Content: Advances and Applications
The need for accurate, real-time, reliable, and multi-scale soil water content (SWC) monitoring is critical for a multitude of scientific disciplines trying to understand and predict the earth’s terrestrial energy, water, and nutrient cycles. One promising technique to help meet this demand is fixed and roving cosmic-ray neutron probes (CRNP). However, the relationship between observed low-energy neutrons and SWC is affected by local soil and vegetation calibration parameters. This effect may be accounted for by a calibrated equation based on local soil type and the amount of standing biomass. However, determining the calibration parameters for this equation is labor and time intensive, thus limiting the full potential of the roving CRNP in large surveys and long transects, or its use in novel environments. In this work, our objective is to develop and test the accuracy of using globally available datasets (clay weight percent, soil bulk density, and soil organic carbon) to support the operability of the CRNP. Here, we develop a 1 km product of soil lattice water over the CONtinental United States (CONUS) using a database of in-situ calibration samples and globally available soil taxonomy and soil texture data. We then test the accuracy of the global dataset in the CONUS using comparisons of 61 in-situ samples of clay percent (RMSE = 5.45 wt. %, R2 = 0.68), soil bulk density (RMSE = 0.173 g/cm3, R2 = 0.203), and soil organic carbon (RMSE = 1.47 wt. %, R2 = 0.175). In addition, we conduct an uncertainty analysis of the global soil calibration parameters using a Monte Carlo error propagation analysis (maximum RSME ~0.035 cm3/cm3 at a SWC = 0.40 cm3/cm3). Fast growing crops (i.e. maize and soybeans) contribute to the CRNP signal primarily through the water within their biomass and this signal must be minimized for soil moisture retrieval. This was done by using a vegetation index derived from MODIS imagery as a proxy for standing wet biomass (RMSE \u3c 1 kg/m2). Lastly, we make recommendations to the design and validation of future roving CRNP experiments.
Advisor: Trenton E. Fran
Bulletin No. 28: The Connecticut Arboretum: Its First Fifty Years 1931 - 1981
56 pp. 1982. Historical accounts of the formation and growth of the Arboretum
Prospectus, January 15, 1971
STUDENT SENATE TO PICK ORANGIZATION OF THE YEAR; Speakers, Films, Panel To Highlight Teach-In Titled About Drugs ; Editors Of Student Newspapers See Censorship As Growing Threat; Problems Of Our Times: Emotion As A Cause; Guest Column; Letters;Bull Page: Ice Skating Party, SWAMP, Wit N\u27 Wisdom, Family Night, Decals, Drug Program, IOC, Student Transfers, Financial Aids, SIU Guest Day, Used Book Store, College Play, Debates Team, Yearbook, Flash Gordon, Vets Meeting, Student Government, Attention All Clubs; Parkland Holds Music Building Workshops; Chemistry Teacher Is Ex-Hockey Plater; Picture Schedule; Illini Freshman Defeat Cobras; I\u27m For Real: Apathy Strikes Cobras; Indoor Track; Danville Over PC; Sport Briefs; Athlete Of The Monthhttps://spark.parkland.edu/prospectus_1971/1016/thumbnail.jp
Selective amplification of glucocorticoid anti-inflammatory activity through synergistic multi-target action of a combination drug
Ultra-high spatial resolution BOLD fMRI in humans using combined segmented-accelerated VFA-FLEET with a recursive RF pulse design
Purpose
To alleviate the spatial encoding limitations of single-shot EPI by
developing multi-shot segmented EPI for ultra-high-resolution fMRI with reduced
ghosting artifacts from subject motion and respiration.
Methods
Segmented EPI can reduce readout duration and reduce acceleration factors,
however, the time elapsed between segment acquisitions (on the order of
seconds) can result in intermittent ghosting, limiting its use for fMRI. Here,
"FLEET" segment ordering--where segments are looped over before slices--was
combined with a variable flip angle progression (VFA-FLEET) to improve
inter-segment fidelity and maximize signal for fMRI. Scaling a sinc pulse's
flip angle for each segment (VFA-FLEET-Sinc) produced inconsistent slice
profiles and ghosting, therefore, a recursive Shinnar-Le Roux (SLR) RF pulse
design was developed (VFA-FLEET-SLR) to generate unique pulses for every
segment that together produce consistent slice profiles and signals.
Results
The temporal stability of VFA-FLEET-SLR was compared against
conventional-segmented EPI and VFA-FLEET-Sinc at 3 T and 7 T. VFA-FLEET-SLR
showed reductions in both intermittent and stable ghosting compared to
conventional-segmented and VFA-FLEET-Sinc, resulting in improved image quality
with a minor trade-off in temporal SNR. Combining VFA-FLEET-SLR with
acceleration, we achieved a 0.6-mm isotropic acquisition at 7 T--without zoomed
imaging or partial Fourier--demonstrating reliable detection of BOLD responses
to a visual stimulus. To counteract the increased repetition time from
segmentation, simultaneous multi-slice VFA-FLEET-SLR was demonstrated using
RF-encoded controlled aliasing.
Conclusions
VFA-FLEET with a recursive RF pulse design supports acquisitions with low
levels of artifact and spatial blur, enabling fMRI at previously inaccessible
spatial resolutions with a "full-brain" field of view.Comment: 51 pages (including supplement), 8 main figures, 6 supporting
figures. For supporting videos (8), please visit
https://github.com/aveberman/vfa-fleet. Note: this work has been accepted for
publication at Magnetic Resonance in Medicin
Surface and lightning sources of nitrogen oxides over the United States: Magnitudes, chemical evolution, and outflow
We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution, and export of NOx. The boundary layer NOx data provide top-down verification of a 50% decrease in power plant and industry NOx emissions over the eastern United States between 1999 and 2004. Observed NOx concentrations at 8–12 km altitude were 0.55 ± 0.36 ppbv, much larger than in previous U.S. aircraft campaigns (ELCHEM, SUCCESS, SONEX) though consistent with data from the NOXAR program aboard commercial aircraft. We show that regional lightning is the dominant source of this upper tropospheric NOx and increases upper tropospheric ozone by 10 ppbv. Simulating ICARTT upper tropospheric NOx observations with GEOS-Chem requires a factor of 4 increase in modeled NOx yield per flash (to 500 mol/ flash). Observed OH concentrations were a factor of 2 lower than can be explained from current photochemical models, for reasons that are unclear. A NOy-CO correlation analysis of the fraction f of North American NOx emissions vented to the free troposphere as NOy (sum of NOx and its oxidation products) shows observed f = 16 ± 10% and modeled f = 14 ± 9%, consistent with previous studies. Export to the lower free troposphere is mostly HNO3 but at higher altitudes is mostly PAN. The model successfully simulates NOy export efficiency and speciation, supporting previous model estimates of a large U.S. anthropogenic contribution to global tropospheric ozone through PAN export
Burden of respiratory viral infection in persons with human immunodeficiency virus
This study was conducted to determine the prevalence of respiratory viral infections (RVI) in persons living with HIV (PLH) admitted with a respiratory complaint using real-time reverse transcription polymerase chain reaction and primer-independent next-generation sequencing (NGS). Of 82 subjects, respiratory viruses were the most common pathogen identified in 27 (33%), followed by fungus and bacteria in 8 (10%) and 4 (5%) subjects, respectively. Among subjects with RVI, 11 (41%) required ICU admission and 16 (59%) required mechanical ventilation. The proportion of respiratory viruses identified, and the associated complicated hospital course highlights the significant role that RVIs play in the lung health of PLH
Chapter sixteen: Rodents and other vertebrate invaders in the United States
Contents
16.1 Introduction 381
16.2 Assessing impacts of rodents and other vertebrate invaders 385
16.3 Accounts of some important vertebrate invaders 38616.3.1 Norway rant (Rattus norvegicus) 38616.3.2 Roof Rat (Rattus rattus) 38716.3.3 Polynesian rat (Rattus exulans) 38816.3.4 House mouse (Mus Musculus) 38816.3.5 Nutria (Myocastor coypus) 38916.3.6 Gambian giant pouched rat (Cricetomys gambianus) 39016.3.7 Feral swine (Sus scofa) 39016.3.8 Small Indian Mongoose (Herpestes javanicus) 39116.3.9 Rock pigeon (Columba livia) 39216.3.10 House sparrow (Passer domesticus) 39316.3.11 European starling (Sturnus vulgaris) 39316.3.12 Monk parakeet (Myiopsitta monachus) 39416.3.13 Brown tree snake (Boiga irregularis) 39516.3.14 Burmese python (Python molurus bivittatus) 39616.3.15 Coqui frog (Eleutherodactylus coqui) 39716.3.16 Sea lamprey (Petromyzon marinus) 39716.3.17 European and Asian carp (Cyprinidae) 398
16.4 Offshore Threats 399
16.5 Discussion 400
Acknowledgements 401
References 40
Chapter sixteen: Rodents and other vertebrate invaders in the United States
Contents
16.1 Introduction 381
16.2 Assessing impacts of rodents and other vertebrate invaders 385
16.3 Accounts of some important vertebrate invaders 38616.3.1 Norway rant (Rattus norvegicus) 38616.3.2 Roof Rat (Rattus rattus) 38716.3.3 Polynesian rat (Rattus exulans) 38816.3.4 House mouse (Mus Musculus) 38816.3.5 Nutria (Myocastor coypus) 38916.3.6 Gambian giant pouched rat (Cricetomys gambianus) 39016.3.7 Feral swine (Sus scofa) 39016.3.8 Small Indian Mongoose (Herpestes javanicus) 39116.3.9 Rock pigeon (Columba livia) 39216.3.10 House sparrow (Passer domesticus) 39316.3.11 European starling (Sturnus vulgaris) 39316.3.12 Monk parakeet (Myiopsitta monachus) 39416.3.13 Brown tree snake (Boiga irregularis) 39516.3.14 Burmese python (Python molurus bivittatus) 39616.3.15 Coqui frog (Eleutherodactylus coqui) 39716.3.16 Sea lamprey (Petromyzon marinus) 39716.3.17 European and Asian carp (Cyprinidae) 398
16.4 Offshore Threats 399
16.5 Discussion 400
Acknowledgements 401
References 40
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