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Baker, John

Publications and source records attributed to Baker, John.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Effects of 5-ion 6-beam sequential irradiation in the presence and absence of hindlimb or control hindlimb unloading on behavioral performances and plasma metabolic pathways of Fischer 344 rats

Introduction Effects and interactions between different spaceflight stressors are expected to be experienced by crew on missions when exposed to microgravity and galactic cosmic rays (GCRs). One of the limitations of previous studies on simulated weightlessness using hindlimb unloading (HU) is that a control HU condition was not included. Methods We characterized the behavioral performance of male Fischer rats 2 months after sham or total body irradiation with a simplified 5-ion 6-mixed-beam exposure representative of GCRs in the absence or presence of HU. Six months later, the plasma, hippocampus, and cortex were processed to determine whether the behavioral effects were associated with long-term alterations in the metabolic pathways. Results In the open field without and with objects, interactions were observed for radiation × HU. In the plasma of animals that were not under the HU or control HU condition, the riboflavin metabolic pathway was affected most for sham irradiation vs. 0.75 Gy exposure. Analysis of the effects of control HU on plasma in the sham-irradiated animals showed that the alanine, aspartate, glutamate, riboflavin, and glutamine metabolisms as well as arginine biosynthesis were affected. The effects of control HU on the hippocampus in the sham-irradiated animals showed that the phenylalanine, tyrosine, and tryptophan pathway was affected the most. Analysis of effects of 0.75 Gy irradiation on the cortex of control HU animals showed that the glutamine and glutamate metabolic pathway was affected similar to the hippocampus, while the riboflavin pathway was affected in animals that were not under the control HU condition. The effects of control HU on the cortex in sham-irradiated animals showed that the riboflavin metabolic pathway was affected. Animals receiving 0.75 Gy of irradiation showed impaired glutamine and glutamate metabolic pathway, whereas animals receiving 1.5 Gy of irradiation showed impaired riboflavin metabolic pathways. A total of 21 plasma metabolites were correlated with the behavioral measures, indicating that plasma and brain biomarkers associated with behavioral performance are dependent on the environmental conditions experienced. Discussion Phenylalanine, tyrosine, and tryptophan metabolism as well as phenylalanine and tryptophan as plasma metabolites are biomarkers that can be considered for spaceflight as they were revealed in both Fischer and WAG/Rij rats exposed to simGCRsim and/or HU.

Physiology↗
DOE OSTI2024

AmeriFlux FLUXNET-1F US-Ro3 Rosemount- G19

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ro3 Rosemount- G19. This is the FLUXNET version of the carbon flux data for the site US-Ro3 Rosemount- G19 produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located in a farm field farmed in accordance with the cominant farming practice in the region: a corn/soybean rotation with chisel plow tillage in the fall following corn harvest and in the spring following soybeans.

Baker, John↗
DOE OSTI2024

Reformulation of dicamba herbicide: Impacts on offsite transport and soybean damage

Abstract The herbicide dicamba (3,6‐dichloro‐2‐methoxybenzoic acid) is commonly used to control broadleaf weeds in soybeans. Dicamba, however, is susceptible to volatilization and drift, thereby causing significant plant damage to nontarget crops downwind. Dicamba was reformulated to reduce volatility and off‐target movement. The effectiveness of the dicamba reformulation was assessed by quantifying dicamba emissions following spray application and investigated how meteorological factors influenced the off‐target movement. The experiments were conducted at the University of Minnesota Agricultural Experiment Station (UMORE Park) during the growing season of 2018, 2019, 2021, and 2022. Multiple high‐flow polyurethane foam air samplers were used to measure dicamba concentrations downwind from a 4‐ha soybean field sprayed with dicamba. Dicamba emissions were estimated using backward Lagrangian modeling constrained by the air sample observations. The results indicate that dicamba emissions and downwind transport were significant for several days following application. Further, non‐traited soybeans located within 15–45 m showed substantial dicamba‐related damage. In warmer, drier seasons, increased dicamba emissions caused more severe damage to downwind soybeans, likely worsened by drought stress preventing recovery. Favorable atmospheric conditions that reduced potential drift can be difficult to achieve in terms of the typical weather experienced over agricultural sites in the Upper Midwest. These results indicate that the dicamba reformulation has not adequately prevented significant post‐spray volatilization losses and downwind transport.

Agriculture↗
DOE OSTI2023

AmeriFlux FLUXNET-1F US-Ro2 Rosemount- C7

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ro2 Rosemount- C7. This is the FLUXNET version of the carbon flux data for the site US-Ro2 Rosemount- C7 produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located in a farm field farmed in accordance with the dominant farming practice in the region: a corn/soybean/clover rotation with chisel plow tillage in the fall following corn harvest and in the spring following soybeans.

Baker, John↗
DOE OSTI2022

AmeriFlux FLUXNET-1F US-Ro1 Rosemount- G21

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ro1 Rosemount- G21. This is the FLUXNET version of the carbon flux data for the site US-Ro1 Rosemount- G21 produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located in a farm field farmed in accordance with the dominant farming practice in the region: a corn/soybean rotation with chisel plow tillage in the fall following corn harvest and in the spring following soybeans.

Baker, John↗
DOE OSTI2022

AmeriFlux FLUXNET-1F US-Ro4 Rosemount Prairie

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ro4 Rosemount Prairie. This is the FLUXNET version of the carbon flux data for the site US-Ro4 Rosemount Prairie produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located in restored prairie in a former agricultural area. Dominant species include Andropogon gerardii, Sorghastrum nutans and Elymus canadensis

Baker, John↗
DOE OSTI2022

AmeriFlux FLUXNET-1F US-Ro6 Rosemount I18_North

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ro6 Rosemount I18_North. This is the FLUXNET version of the carbon flux data for the site US-Ro6 Rosemount I18_North produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located in a farm field farmed in accordance with a conservation type agricultural practice in the region: a corn/soybean/clover (living mulch/cover crop) rotation with chisel plow tillage in the fall following corn harvest and in the spring following soybeans.

Baker, John↗
NASA NTRS2022

Night Sky Testing of the Lunar Flashlight Star Tracker

Lunar Flashlight (LF) is a 6U, 14 kg spacecraft being built by the NASA Jet Propulsion Laboratory (JPL). The mission will use IR laser technology to search for volatiles and surface water ice deposits in the permanently shadowed regions (PSR) of the moon in preparation for future human lunar exploration. The fine pointing provided by the Guidance, Navigation and Control (GNC) system is crucial for the spacecraft to successfully reach the moon, enter a lunar orbit, and acquire scientific data. At the center of the GNC system’s ability to determine the spacecraft’s attitude is a star tracker. The LF star tracker is a commercial-off-the-shelf (COTS) unit built into the integrated GNC system provided by Blue Canyon Technologies. Blue Canyon tested the star tracker in a lab environment for basic functionality and attitude estimation capabilities; upon delivery of the hardware to JPL, further testing with a real night sky was desired to determine expected in-flight operational characteristics. JPL maintains the Table Mountain Facility with its suite of ground telescopes, including a 0.6m telescope with an equatorial mount. This stable platform provided a highly accurate method of providing slews and attitude holds akin to what the spacecraft will perform in flight. Therefore, by analyzing the data from these representative night-sky ground tests performed in March, 2021, it is possible to acquire expected flight performance of the star tracker, particularly in regard to the ability of the star tracker to maintain lock on the starfield during planned maneuver types. This paper presents the various tests that have been performed to ensure that the LF star tracker will function as part of the overall GNC system and integrated spacecraft once launched. Test data is included for several key tests, and a path forward towards future integration and testing at the spacecraft level is described.

Baker, John↗
DOE OSTI2021

Effects of 5-Ion Beam Irradiation and Hindlimb Unloading on Metabolic Pathways in Plasma and Brain of Behaviorally Tested WAG/Rij Rats

A limitation of simulated space radiation studies is that radiation exposure is not the only environmental challenge astronauts face during missions. Therefore, we characterized behavioral and cognitive performance of male WAG/Rij rats 3 months after sham-irradiation or total body irradiation with a simplified 5-ion mixed beam exposure in the absence or presence of simulated weightlessness using hindlimb unloading (HU) alone. Six months following behavioral and cognitive testing or 9 months following sham-irradiation or total body irradiation, plasma and brain tissues (hippocampus and cortex) were processed to determine whether the behavioral and cognitive effects were associated with long-term alterations in metabolic pathways in plasma and brain. Sham HU, but not irradiated HU, rats were impaired in spatial habituation learning. Rats irradiated with 1.5 Gy showed increased depressive-like behaviors. This was seen in the absence but not presence of HU. Thus, HU has differential effects in sham-irradiated and irradiated animals and specific behavioral measures are associated with plasma levels of distinct metabolites 6 months later. The combined effects of HU and radiation on metabolic pathways in plasma and brain illustrate the complex interaction of environmental stressors and highlights the importance of assessing these interactions.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2021

AmeriFlux FLUXNET-1F US-Ro5 Rosemount I18_South

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Ro5 Rosemount I18_South. This is the FLUXNET version of the carbon flux data for the site US-Ro5 Rosemount I18_South produced by applying the standard ONEFlux (1F) software. Site Description - This tower is located in a farm field farmed in accordance with the dominant farming practice in the region: a corn/soybean rotation with chisel plow tillage in the fall following corn harvest and in the spring following soybeans.

Baker, John↗
DOE OSTI2021

Monitoring agroecosystem productivity and phenology at a national scale: A metric assessment framework

Effective measurement of seasonal variations in the timing and amount of production is critical to managing spatially heterogeneous agroecosystems in a changing climate. Although numerous technologies for such measurements are available, their relationships to one another at a continental extent are unknown. Using data collected from across the Long-Term Agroecosystem Research (LTAR) network and other networks, we investigated correlations among key metrics representing primary production, phenology, and carbon fluxes in croplands, grazing lands, and crop-grazing integrated systems across the continental U.S. Metrics we examined included gross primary productivity (GPP) estimated from eddy covariance (EC) towers and modelled from the Landsat satellite, Landsat NDVI, and vegetation greenness (Green Chromatic Coordinate, GCC) from tower-mounted PhenoCams for 2017 and 2018. Overall, our analysis compared production dynamics estimated from three independent ground and remote platforms using data for 34 agricultural sites constituting 51 site-years of co-located time series. Pairwise sensor comparisons across all four metrics revealed stronger correlation and lower root mean square error (RMSE) between end of season (EOS) dates (Pearson R ranged from 0.6 to 0.7 and RMSE from 32.5 to 67.8) than start of season (SOS) dates (0.46 to 0.69 and 40.4 to 66.2). Overall, moderate to high correlations between SOS and EOS metrics complemented one another except at some lower productivity grazing land sites where estimating SOS can be challenging. Growing season length estimates derived from 16-day satellite GPP (179.1 days) were significantly longer than those from PhenoCam G CC (70.4 days, p adj < 0.0001) and EC GPP (79.6 days, p adj < 0.0001). Landscape heterogeneity did not explain differences in SOS and EOS estimates. Annual integrated estimates of productivity from EC GPP and PhenoCam G CC diverged from those estimated by Landsat GPP and NDVI at sites where annual production exceeds 1000 gC/m –2 yr –1 . Based on our results, we developed a “metric assessment framework” that articulates where and how metrics from satellite, eddy covariance and PhenoCams complement, diverge from, or are redundant with one another. The framework was designed to optimize instrumentation selection for monitoring, modeling, and forecasting ecosystem functioning with the ultimate goal of informing decision-making by land managers, policy-makers, and industry leaders working at multiple scales.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2021

Development of a CubeSat-Scale Green Monopropellant Propulsion System for NASA's Lunar Flashlight Mission

NASA's Lunar Flashlight is a low-cost 6U CubeSat whose mission is to search for ice and mineral deposits inside of the scattered craters at Moon's southern pole. To conduct its primary science mission, Lunar Flashlight must be placed in a stable lunar polar orbit which requires the utilization of an on-board propulsion system. However, to this date, most CubeSats have been propelled by cold-gas or electric propulsion systems that have proven to scale well but lack sufficient impulse to conduct large $\Delta V$ maneuvers such as orbit insertions. To this end, the Lunar Flashlight mission has chosen to utilize a custom-designed green monopropellant propulsion system developed by the Georgia Institute of Technology under the leadership of NASA's Marshall Space Flight Center and support from the Jet Propulsion Laboratory. The developed system is capable of providing more than the required propulsive capability for full mission success while fitting inside of a 2.5U volume and weighing less than six kilograms. The system utilizes the Advanced Space Craft Energetic Non Toxic (ASCENT) green monopropellant that provides higher specific impulse compared to traditional hydrazine while also being safer to handle. If successful, the presented propulsion system will enable Lunar Flashlight to be the first CubeSat to reach the Moon, the first to conduct an orbit insertion, and will be the first CubeSat demonstration of the ASCENT propellant.

Kowalkowski, Matthew↗
DOE OSTI2020

KCMP Minnesota Tall Tower Carbon Dioxide Data 2007-2019

This data set contains carbon dioxide concentration values and supporting metadata information measured at a tall tower (KCMP radio station, 244 meters) site near St. Paul, Minnesota, USA. The data package includes a text file containing hourly continuous carbon dioxide concentration measurements from 2007 to 2019, including raw, de-spiked, and gap filled data. Carbon dioxide concentrations were measured at approximately 100 meters using tunable diode laser spectroscopy. The instrumentation was maintained at the base of the tall tower in a temperature-controlled building. This data was collected to track and improve the understanding of carbon dioxide levels over a twelve year period for the region.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2020

Opportunistic Arraying

This paper discusses recent activities at JPL that are focused on extending the Opportunistic Multiple Spacecraft Per Antenna (OMSPA) concept to include arraying multiple antennas. Specifically, we explore the ability to process multiple open loop recordings associated with multiple antennas and perform the appropriate alignment and combining. We focus on using the symbol stream combining technique and provide examples of performance measurements on actual spacecraft signals for MarCO A and B as well as the Mars Express.

Johnstone, Andrew↗
NASA NTRS2020

Opportunistic Arraying

This paper discusses recent activities at JPL that are focused on extending the Opportunistic Multiple Spacecraft Per Antenna (OMSPA) concept to include arraying multiple antennas. Specifically, we explore the ability to process multiple open loop recordings associated with multiple antennas and perform the appropriate alignment and combining. We focus on using the symbol stream combining technique and provide examples of performance measurements on actual spacecraft signals for MarCO A and B as well as the Mars Express.

Okino, Clayton↗
DOE OSTI2020

Evaporation Dataset from a Temperate Closed-basin Lake in Minnesota 2014-2016

This data set contains observed and modeled evaporation data, eddy covariance data, and supporting information measured at White Bear Lake in the Twin Cities Metropolitan Area near St. Paul, Minnesota, USA. The data package includes csv files containing half-hourly latent heat flux, sensible heat flux, and meteorological data from 2014 to 2016. It also includes csv files containing half-hourly observed evaporation measurements, along with supporting data for validation and retrospective modeling of evaporation. This data was collected to examine current, past, and future lake evaporation to better understand how climate will impact the water balance of lakes within this region.

54 ENVIRONMENTAL SCIENCES↗