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At least 55 records · Page 3

A submillimeter galaxy illuminating its circumgalactic medium: Lyα scattering in a cold, clumpy outflow

We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

79 ASTRONOMY AND ASTROPHYSICS↗

Simulated impact of the renewable fuels standard on US Conservation Reserve Program enrollment and conversion

Abstract A socioeconomic model is used to estimate the land‐use implications on the U.S. Conservation Reserve Program from potential increases in second‐generation biofuel production. A baseline scenario with no second‐generation biofuel production is compared to a scenario where the Renewable Fuels Standard ( RFS 2) volumes are met by 2022. We allow for the possibility of converting expiring CRP lands to alternative uses such as conventional crops, dedicated second‐generation biofuel crops, or harvesting existing CRP grasses for biomass. Results indicate that RFS 2 volumes ( RFS 2‐v) can be met primarily with crop residues (78% of feedstock demand) and woody residues (19% of feedstock demand) compared with dedicated biomass (3% of feedstock demand), with only minimal conversion of cropland (0.27 million hectares, <1% of total cropland), pastureland (0.28 million hectares of pastureland, <1% of total pastureland), and CRP lands (0.29 million hectares of CRP lands, 3% of existing CRP lands) to biomass production. Meeting RFS 2 volumes would reduce CRP re‐enrollment by 0.19 million hectares, or 4%, below the baseline scenario where RFS 2 is not met. Yet under RFS 2‐v scenario, expiring CRP lands are more likely to be converted to or maintain perennial cover, with 1.78 million hectares of CRP lands converting to hay production, and 0.29 million hectares being harvested for existing grasses. A small amount of CRP is harvested for existing biomass, but no conversion of CRP to dedicated biomass crops, such as switchgrass, are projected to occur. Although less land is enrolled in CRP under RFS 2‐v scenario, total land in perennial cover increases by 0.15 million hectares, or 2%, under RFS 2‐v. Sensitivity to yield, payment and residue retention assumptions are evaluated.

09 BIOMASS FUELS↗

Effect of biochanin A on the rumen microbial community of Holstein steers consuming a high fiber diet and subjected to a subacute acidosis challenge

Subacute rumen acidosis (SARA) occurs when highly fermentable carbohydrates are introduced into the diet, decreasing pH and disturbing the microbial ecology of the rumen. Rumen amylolytic bacteria rapidly catabolize starch, fermentation acids accumulate in the rumen and reduce environmental pH. Historically, antibiotics ( e . g ., monensin, MON) have been used in the prevention and treatment of SARA. Biochanin A (BCA), an isoflavone produced by red clover ( Trifolium pratense ), mitigates changes associated with starch fermentation ex vivo . The objective of the study was to determine the effect of BCA on amylolytic bacteria and rumen pH during a SARA challenge. Twelve rumen fistulated steers were assigned to 1 of 4 treatments: HF CON (high fiber control), SARA CON, MON (200 mg d -1 ), or BCA (6 g d -1 ). The basal diet consisted of corn silage and dried distiller’s grains ad libitum . The study consisted of a 2-wk adaptation, a 1-wk HF period, and an 8-d SARA challenge (d 1–4: 40% corn; d 5–8: 70% cracked corn). Samples for pH and enumeration were taken on the last day of each period (4 h). Amylolytic, cellulolytic, and amino acid/peptide-fermenting bacteria (APB) were enumerated. Enumeration data were normalized by log transformation and data were analyzed by repeated measures ANOVA using the MIXED procedure of SAS. The SARA challenge increased total amylolytics and APB, but decreased pH, cellulolytics, and in situ DMD of hay (P < 0.05). BCA treatment counteracted the pH, microbiological, and fermentative changes associated with SARA challenge (P < 0.05). Similar results were also observed with MON (P < 0.05). These results indicate that BCA may be an effective alternative to antibiotics for mitigating SARA in cattle production systems.

59 BASIC BIOLOGICAL SCIENCES↗

Tracking cropland transitions: A comparative analysis of U.S. land cover change data

There are a growing number of land cover data available for the conterminous United States, supporting various applications ranging from biofuel regulatory decisions to habitat conservation assessments. These datasets vary in their source information, frequency of data collection and reporting, land class definitions, categorical detail, and spatial scale and time intervals of representation. These differences limit direct comparison, contribute to disagreements among studies, confuse stakeholders, and hamper our ability to confidently report key land cover trends in the U.S. Here we assess changes in cropland derived from the Land Change Monitoring, Assessment, and Projection (LCMAP) dataset from the U.S. Geological Survey and compare them with analyses of three established land cover datasets across the coterminous U.S. from 2008-2017: (1) the National Resources Inventory (NRI), (2) a dataset Lark et al. 2020 derived from the Cropland Data Layer (CDL), and (3) a dataset from Potapov et al. 2022. LCMAP reports more stable cropland and less stable noncropland in all comparisons, likely due to its more expansive definition of cropland which includes managed grasslands (pasture and hay). Despite these differences, net cropland expansion from all four datasets was comparable (5.18-6.33 million acres), although the geographic extent and type of conversion differed. LCMAP projected the largest cropland expansion in the southern Great Plains, whereas other datasets projected the largest expansion in the northwestern and central Midwest. Most of the pixel-level disagreements (86%) between LCMAP and Lark et al. 2020 were due to definitional differences among datasets, whereas the remainder (14%) were from a variety of causes. Cropland expansion in the LCMAP likely reflects conversions of more natural areas, whereas cropland expansion in other data sources also captures conversion of managed pasture to cropland. The particular research question considered (e.g., habitat versus soil carbon) should influence which data source is more appropriate.

60 APPLIED LIFE SCIENCES↗

Remotely Sensed Thermal Anomalies in Western Colorado

This layer contains the areas identified as areas of anomalous surface temperature from Landsat satellite imagery in Western Colorado. Data was obtained for two different dates. The digital numbers of each Landsat scene were converted to radiance and the temperature was calculated in degrees Kelvin and then converted to degrees Celsius for each land cover type using the emissivity of that cover type. And this process was repeated for each of the land cover types (open water, barren, deciduous forest and evergreen forest, mixed forest, shrub/scrub, grassland/herbaceous, pasture hay, and cultivated crops). The temperature of each pixel within each scene was calculated using the thermal band. In order to calculate the temperature an average emissivity value was used for each land cover type within each scene. The NLCD 2001 land cover classification raster data of the zones that cover Colorado were downloaded from USGS site and used to identify the land cover types within each scene. Areas that had temperature residual greater than 2o, and areas with temperature equal to 1o to 2o, were considered Landsat modeled very warm and warm surface exposures (thermal anomalies), respectively. Note: 'o' is used in this description to represent lowercase sigma.

15 GEOTHERMAL ENERGY↗

AmeriFlux US-Dk1 Duke Forest-open field

This is the AmeriFlux version of the carbon flux data for the site US-Dk1 Duke Forest-open field. Site Description - The Duke Forest grass field is approximately 480×305 m, dominated by the C3 grass Festuca arundinacea Shreb. (tall fescue) includes minor components of C3 herbs and the C4 grass Schizachyrium scoparium (Michx.) Nash, not considered here. The site was burned in 1979 and is mowed annually during the summer for hay according to local practices. Lai, C.T. and G.G. Katul, 2000, "The dynamic role of root-water uptake in coupling potential to actual transpiration" , Advances in Water Resources, 23, 427-439; Novick , K.A., P. C. Stoy, G. G. Katul, D. S. Ellsworth, M. B. S. Siqueira, J. Juang, R. Oren, 2004, Carbon dioxide and water vapor exchange in a warm temperate grassland, Oecologia, 138, 259-274; Stoy PC, Katul GG, Siqueira MBS, Juang J-Y, McCarthy HR, Oishi AC, Uebelherr JM, Kim H-S, Oren R (2006). Separating the effects of climate and vegetation on evapotranspiration along a successional chronosequence in the southeastern U.S. Global Change Biology 12:2115-2135

Oishi, Chris↗

AmeriFlux US-KFS Kansas Field Station

This is the AmeriFlux version of the carbon flux data for the site US-KFS Kansas Field Station. Site Description - The study is an abandoned grassland at the Kansas Field Station and Ecological Reserves. The site is located within the tallgrass prairie-deciduous forest ecotonal area. The site was subjected to intensive agriculture from the 1940s through the late 1960s. In the mid-1970s, the site was planted with the cool-season grass Bromus inermis and used as a hay meadow until 1987. Then, mowing and burning approximately every five years maintained it as a grassland until 2007, when the eddy flux tower was installed.

Brunsell, Nathaniel↗

AmeriFlux CA-MA3 Manitoba Agricultural Site 3

This is the AmeriFlux version of the carbon flux data for the site CA-MA3 Manitoba Agricultural Site 3. Site Description - This field has been in perennial forages (grass (timothy, fescue, brome) with small amount of legume) for several decades. Field size = 40 ha. Hay was harvested once each year. Cattle were placed in the field each autumn to graze. See Table 1 in Taylor et al (2013) describing site management practices.

Amiro, Brian↗

AmeriFlux US-Mo1 LTAR CMRB Field 1 (CMRB ASP)

This is the AmeriFlux version of the carbon flux data for the site US-Mo1 LTAR CMRB Field 1 (CMRB ASP). Site Description - Site is in a 36 ha agricultural research field near Centralia, MO on a broad, slightly sloped landscape. Currently farmed in a corn-soybean-wheat-hay rotation. Used for research since 1991; prior to that was managed for commercial crop production.

Schreiner-McGraw, Adam↗

AmeriFlux FLUXNET-1F US-KFS Kansas Field Station

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-KFS Kansas Field Station. This is the FLUXNET version of the carbon flux data for the site US-KFS Kansas Field Station produced by applying the standard ONEFlux (1F) software. Site Description - The study is an abandoned grassland at the Kansas Field Station and Ecological Reserves. The site is located within the tallgrass prairie-deciduous forest ecotonal area. The site was subjected to intensive agriculture from the 1940s through the late 1960s. In the mid-1970s, the site was planted with the cool-season grass Bromus inermis and used as a hay meadow until 1987. Then, mowing and burning approximately every five years maintained it as a grassland until 2007, when the eddy flux tower was installed.

Brunsell, Nathaniel↗

AmeriFlux FLUXNET-1F CA-MA3 Manitoba Agricultural Site 3

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-MA3 Manitoba Agricultural Site 3. This is the FLUXNET version of the carbon flux data for the site CA-MA3 Manitoba Agricultural Site 3 produced by applying the standard ONEFlux (1F) software. Site Description - This field has been in perennial forages (grass (timothy, fescue, brome) with small amount of legume) for several decades. Field size = 40 ha. Hay was harvested once each year. Cattle were placed in the field each autumn to graze. See Table 1 in Taylor et al (2013) describing site management practices.

Amiro, Brian↗

AmeriFlux FLUXNET-1F US-Mo1 LTAR CMRB Field 1 (CMRB ASP)

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Mo1 LTAR CMRB Field 1 (CMRB ASP). This is the FLUXNET version of the carbon flux data for the site US-Mo1 LTAR CMRB Field 1 (CMRB ASP) produced by applying the standard ONEFlux (1F) software. Site Description - Site is in a 36 ha agricultural research field near Centralia, MO on a broad, slightly sloped landscape. Currently farmed in a corn-soybean-wheat-hay rotation. Used for research since 1991; prior to that was managed for commercial crop production.

Schreiner-McGraw, Adam↗

AmeriFlux FLUXNET-1F US-Dk1 Duke Forest-open field

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-Dk1 Duke Forest-open field. This is the FLUXNET version of the carbon flux data for the site US-Dk1 Duke Forest-open field produced by applying the standard ONEFlux (1F) software. Site Description - The Duke Forest grass field is approximately 480×305 m, dominated by the C3 grass Festuca arundinacea Shreb. (tall fescue) includes minor components of C3 herbs and the C4 grass Schizachyrium scoparium (Michx.) Nash, not considered here. The site was burned in 1979 and is mowed annually during the summer for hay according to local practices. Lai, C.T. and G.G. Katul, 2000, "The dynamic role of root-water uptake in coupling potential to actual transpiration" , Advances in Water Resources, 23, 427-439; Novick , K.A., P. C. Stoy, G. G. Katul, D. S. Ellsworth, M. B. S. Siqueira, J. Juang, R. Oren, 2004, Carbon dioxide and water vapor exchange in a warm temperate grassland, Oecologia, 138, 259-274; Stoy PC, Katul GG, Siqueira MBS, Juang J-Y, McCarthy HR, Oishi AC, Uebelherr JM, Kim H-S, Oren R (2006). Separating the effects of climate and vegetation on evapotranspiration along a successional chronosequence in the southeastern U.S. Global Change Biology 12:2115-2135

Oishi, Chris [USDA Forest Service]↗

Consideration of HTS rapid-cycling magnet for staged muon acceleration

The HTS conductor hysteresis dominates magnet cable power loss but is independent of the magnetic field ramping rate. This makes the HTS conductor suitable to power the rapid-cycling accelerator magnet. We present a possible application of the HTS rapid-cycling magnet as outlined in [1,2] for the staged muon acceleration including the front-end Recirculating Linear Accelerator and the followed-up Rapid Cycling Synchrotrons delivering the muon beams to the Muon Collider.[1] H. Piekarz, S. Otten, A. Kario, H. ten Kate, “Rapid-cycling HTS magnet for muon acceleration”, US MC Inaugural Meeting, FERMILAB-POSTER-24-0219-AD, August 7-9, 2024[2] H. Piekarz, B. Claypool, S. Hays, M. Kufer, V. Shiltsev, “Record High Ramping Rates in HTS Based Supercond. Accelerator Magnet”, MT 27, IEEE Trans. on Applied Superccond, 32 (2022) 6, 4100404

Piekarz, Henryk [Fermilab]↗

Multispecies Diffusion Capability For The AMP Nuclear Fuel Performance Code (LANL Milestone M31MS060301 Final Report)

This work addresses only diffusion. The contact solver in AMP was not sufficiently developed this year to attempt treatment of species contact. A cylindrical tensor diffusion coefficient model was added to the AMP code, with the KHHS model [1] implemented into the AMP material library as a specific example. A cylindrical tensor diffusion operator manufactured solution verification example was coded. Before meeting the full text of the milestone task, it remains to: (1) code and run a cylindrical tensor diffusion solver manufactured solution (2) code and run the validation example of [1] (3) document results. These are dependent on developing new capabilities for the AMP code requiring close collaboration with the AMP team at ORNL. The model implemented provides a good intermediate first step toward a general multi-species solver. The multi-species capability of the AMP nuclear fuel code [2] is intended to allow the modeling of radiation-driven redistribution of various elements through solid metal nuclear reactor fuels. The initial model AMP provides for U-Pu-Zr fuels is based on the analysis of the Integral Fast Reactor (IFR) fuel development program experiment X419 post-irradiation data described in [1], referred to here as the KHHS model. This model may be specific to that experiment, but it was thought to provide a good start for the AMP code, because it (1) is formulated at the engineering scale, (2) decouples the species from each other, (3) predetermines the phase boundaries so that reference to a phase diagram is not needed, and (4) one of the authors (Hayes) was the NEAMS Fuels IPSC manager for FY11. The KHHS model is formulated for radial fluxes as little axial redistribution is seen experimentally. As U-Pu-Zr fuel is irradiated, the constituents migrate to form three annular regions. The center region is Zr-enriched and U-depleted, the middle region is Zr-depleted and U-enriched, and the outer region is Zr-enriched and U-depleted. The Pu concentration stays roughly constant throughout with slight enrichment in the center and depletion near the surface. Pu acts as a solvent for the mixture. The experiment was only run to 1.9% burnup, so the model is not at this time applicable to the high-burnup scenarios that the AMP code is intended to eventually model.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Agricultural Industry Advanced Vehicle Technology: Benchmark Study for Reduction in Petroleum Use

Diesel use on farms in the United States has remained relatively constant since 1985, decreasing slightly in 2009, which may be attributed to price increases and the economic recession. During this time, the United States’ harvested area also has remained relatively constant at roughly 300 million acres. In 2010, farm diesel use was 5.4% of the total United States diesel use. Crops accounting for an estimated 65% of United States farm diesel use include corn, soybean, wheat, hay, and alfalfa, respectively, based on harvested crop area and a recent analysis of estimated fuel use by crop. Diesel use in these cropping systems primarily is from tillage, harvest, and various other operations (e.g., planting and spraying) (Figure 3). Diesel efficiency is markedly variable due to machinery types, conditions of operation (e.g., soil type and moisture), and operator variability. Farm diesel use per acre has slightly decreased in the last two decades and diesel is now estimated to be less than 5% of farm costs per acre. This report will explore current trends in increasing diesel efficiency in the farm sector. The report combines a survey of industry representatives, a review of literature, and data analysis to identify nascent technologies for increasing diesel efficiency.

33 ADVANCED PROPULSION SYSTEMS↗

Identifying and Mitigating Potential Nutrient and Sediment Hot Spots under a Future Scenario in the Missouri River Basin

Using the Soil and Water Assessment Tool (SWAT) for large-scale watershed modeling could be useful for evaluating the quality of the water in regions that are dominated by nonpoint sources in order to identify potential “hot spots” for which mitigating strategies could be further developed. An analysis of water quality under future scenarios in which changes in land use would be made to accommodate increased biofuel production was developed for the Missouri River Basin (MoRB) based on a SWAT model application. The analysis covered major agricultural crops and biofuel feedstock in the MoRB, including pasture land, hay, corn, soybeans, wheat, and switchgrass. The analysis examined, at multiple temporal and spatial scales, how nitrate, organic nitrogen, and total nitrogen; phosphorus, organic phosphorus, inorganic phosphorus, and total phosphorus; suspended sediments; and water flow (water yield) would respond to the shifts in land use that would occur under proposed future scenarios. The analysis was conducted at three geospatial scales: (1) large tributary basin scale (two: Upper MoRB and Lower MoRB); (2) regional watershed scale (seven: Upper Missouri River, Middle Missouri River, Middle Lower Missouri River, Lower Missouri River, Yellowstone River, Platte River, and Kansas River); and (3) eight-digit hydrologic unit (HUC-8) subbasin scale (307 subbasins). Results showed that subbasin-level variations were substantial. Nitrogen loadings decreased across the entire Upper MoRB, and they increased in several subbasins in the Lower MoRB. Most nitrate reductions occurred in lateral flow. Also at the subbasin level, phosphorus in organic, sediment, and soluble forms was reduced by 35%, 45%, and 65%, respectively. Suspended sediments increased in 68% of the subbasins. The water yield decreased in 62% of the subbasins. In the Kansas River watershed, the water quality improved significantly with regard to every nitrogen and phosphorus compound. The improvement was clearly attributable to the conversion of a large amount of land to switchgrass. The Middle Lower Missouri River and Lower Missouri River were identified as hot regions. Further analysis identified four subbasins (10240002, 10230007, 10290402, and 10300200) as being the most vulnerable in terms of sediment, nitrogen, and phosphorus loadings. Overall, results suggest that increasing the amount of switchgrass acreage in the hot spots should be considered to mitigate the nutrient loads. The study provides an analytical method to support stakeholders in making informed decisions that balance biofuel production and water sustainability.

land use change↗

Organization of the 16th Advanced Accelerator Concepts (AAC) Workshop by Stanford University

Essentially all we know today and will learn in the future about the fundamental nature of matter is derived from probing it with directed beams of particles such as electrons, protons, neutrons, heavy ions, and photons. The resulting ability to “see” the building blocks of matter has had an immense impact on society and our standard of living. Over the last century, particle accelerators have changed the way we look at nature and the universe we live in and have become an integral part of the Nation’s technical infrastructure. Today, particle accelerators are essential tools of modern science and technology. The cost and capabilities of accelerators would be greatly enhanced by breakthroughs in acceleration methods and technology. For the last 32 years, the Advanced Accelerator Concepts (AAC) Workshop has acted as the focal point for discussion and development of the most promising acceleration physics and technology. It is a particularly effective forum where the discussion is leveraged and promoted by the unique and demanding feature of the AAC Workshop: the working group structure, in which participants are asked to consider their contributions in terms of even larger problems to be solved. The 16th Advanced Accelerator Concepts (AAC2014) Workshop was organized by Stanford University from July 13 - 18, 2014 at the Dolce Hays Mansion in San Jose, California. The conference had a record 282 attendees including 62 students. Attendees came from 11 countries representing 66 different institutions. The workshop format consisted of plenary sessions in the morning with topical leaders from around the world presenting the latest breakthroughs to the entire workshop. In the late morning and afternoons attendees broke out into eight different working groups for more detailed presentations and discussions that were summarized on the final day of the workshop. In addition, there were student tutorial presentations on two afternoons to provide in depth education and training for the next generation of accelerator scientists. This is the final technical report on the organization and outcome of AAC2014.

43 PARTICLE ACCELERATORS↗