Inspired by laboratory experiments showing internal waves generated by a plume impinging upon a stratified fluid layer (Ansong & Sutherland. 2010 J. Fluid Mech. 648, 405–434), we perform large eddy simulations in three dimensions to examine the structure and source of internal waves emanating from the top of a plume that rises vertically into stratification whose strength ranges over two orders of magnitude between different simulations. Provided the plume is sufficiently energetic to penetrate into the stratified layer, internal waves are generated with frequencies in a relatively narrow band moderately smaller than the buoyancy frequency. Through adaptations of ray theory including viscosity and use of dynamic mode decomposition, we show that the waves originate from within the turbulent flow rather than at the turbulent/non-turbulent interface between the fountain top and the surrounding stratified fluid.

North Carolina growers have long struggled to control Italian ryegrass, and recent research has confirmed that some Italian ryegrass biotypes have become resistant to nicosulfuron, glyphosate, clethodim, and paraquat. Integrating alternative management strategies is crucial to effectively control such biotypes. The objectives of this study were to evaluate Italian ryegrass control with cover crops and fall-applied residual herbicides and investigate cover crop injury from residual herbicides. This study was conducted during the fall/winter of 2021–22 in Salisbury, NC, and fall/winter of 2021–22 and 2022–23 in Clayton, NC. The study was designed as a 3 × 5 split-plot in which the main plot consisted of three cover crop treatments (no-cover, cereal rye at 80 kg ha−1, and crimson clover at 18 kg ha−1), and the subplots consisted of five residual herbicide treatments (S-metolachlor, flumioxazin, metribuzin, pyroxasulfone, and nontreated). In the 2021–22 season at Clayton, metribuzin injured cereal rye and crimson clover 65% and 55%, respectively. However, metribuzin injured both cover crops ≤6% in 2022–23. Flumioxazin resulted in unacceptable crimson clover injury of 50% and 38% in 2021–22 and 2022–23 in Clayton and 40% in Salisbury, respectively. Without preemergence herbicides, cereal rye controlled Italian ryegrass by 85% and 61% at 24 wk after planting in 2021–22 and 2022–23 in Clayton and 82% in Salisbury, respectively. In 2021–22, Italian ryegrass seed production was lowest in cereal rye plots at both locations, except when it was treated with metribuzin. For example, in Salisbury, cereal rye plus metribuzin resulted in 39,324 seeds m–2, compared to ≤4,386 seeds m–2 from all other cereal rye treatments. In 2022–23, Italian ryegrass seed production in cereal rye was lower when either metribuzin or pyroxasulfone were used preemergence (2,670 and 1,299 seeds m–2, respectively) compared with cereal rye that did not receive an herbicide treatment (5,600 seeds m–2). cereal rye (Secale cereale L.) and crimson clover (Trifolium incarnatum L.)

Two studies were conducted in 2022 and 2023 near Rocky Mount and Clayton, NC, to determine the optimal granular ammonium sulfate (AMS) rate and application timing for pyroxasulfone-coated AMS. In the rate study, AMS rates included 161, 214, 267, 321, 374, 428, and 481 kg ha−1, equivalent to 34, 45, 56, 67, 79, 90, and 101 kg N ha−1, respectively. All rates were coated with pyroxasulfone at 118 g ai ha−1 and topdressed onto 5- to 7-leaf cotton. In the timing study, pyroxasulfone (118 g ai ha−1) was coated on AMS and topdressed at 321 kg ha−1 (67 kg N ha−1) onto 5- to 7-leaf, 9- to 11-leaf, and first bloom cotton. In both studies, weed control and cotton tolerance to pyroxasulfone-coated AMS were compared to pyroxasulfone applied POST and POST-directed. The check in both studies received non-herbicide-treated AMS (321 kg ha−1). Before treatment applications, all plots (including the check) were maintained weed-free with glyphosate and glufosinate. In both studies, pyroxasulfone applied POST was most injurious (8% to 16%), while pyroxasulfone-coated AMS resulted in ≤4% injury. Additionally, no differences in cotton lint yield were observed in either study. With the exception of the lowest rate of AMS (161 kg ha−1; 79%), all AMS rates coated with pyroxasulfone controlled Palmer amaranth ≥83%, comparably to pyroxasulfone applied POST (92%) and POST-directed (89%). In the timing study, the application method did not affect Palmer amaranth control; however, applications made at the mid- and late timings outperformed early applications. These results indicate that pyroxasulfone-coated AMS can control Palmer amaranth comparably to pyroxasulfone applied POST and POST-directed, with minimal risk of cotton injury. However, the application timing could warrant additional treatment to achieve adequate late-season weed control.

An experiment was conducted in 2022 and 2023 near Rocky Mount and Clayton, NC, to evaluate residual herbicide-coated fertilizer for cotton tolerance and Palmer amaranth control. Treatments included acetochlor, atrazine, dimethenamid-P, diuron, flumioxazin, fluometuron, fluridone, fomesafen, linuron, metribuzin, pendimethalin, pyroxasulfone, pyroxasulfone + carfentrazone, S-metolachlor, and sulfentrazone. Each herbicide was individually coated on granular ammonium sulfate (AMS) and top-dressed at 321 kg ha−1 (67 kg N ha−1) onto 5- to 7-leaf cotton. The check plots received the equivalent rate of nonherbicide-treated AMS. Before top-dress, all plots (including the check) were treated with glyphosate and glufosinate to control previously emerged weeds. All herbicides except metribuzin resulted in transient cotton injury. Cotton response to metribuzin varied by year and location. In 2022, metribuzin caused 11% to 39% and 8% to 17% injury at the Clayton and Rocky Mount locations, respectively. In 2023, metribuzin caused 13% to 32% injury at Clayton and 73% to 84% injury at Rocky Mount. Pyroxasulfone (91%), pyroxasulfone + carfentrazone (89%), fomesafen (87%), fluridone (86%), flumioxazin (86%), and atrazine (85%) controlled Palmer amaranth ≥85%. Pendimethalin and fluometuron were the least effective treatments, resulting in 58% and 62% control, respectively. As anticipated, early season metribuzin injury translated into yield loss; plots treated with metribuzin yielded 640 kg ha−1 and were comparable to yields after linuron (790 kg ha−1) was used. These findings suggest that with the exception of metribuzin, residual herbicides coated onto AMS may be suitable and effective in cotton production, providing growers with additional modes of action for late-season control of multiple herbicide–resistant Palmer amaranth.

We use large-eddy simulations to study the penetration of a buoyant plume carrying a passive tracer into a stably stratified layer with constant buoyancy frequency. Using a buoyancy-tracer volume distribution, we develop a method for objectively partitioning plume fluid in buoyancy-tracer space into three regions, each of which corresponds to a coherent region in physical space. Specifically, we identify a source region where undiluted plume fluid enters the stratified layer, a transport region where much of the transition from undiluted to mixed fluid occurs in the plume cap and an accumulation region corresponding to a radially spreading intrusion. This method enables quantification of different measures of turbulence and mixing within each of the three regions, including potential energy and turbulent kinetic energy dissipation rates, an activity parameter and the instantaneous mixing efficiency. We find that the most intense buoyancy gradients lie in a thin layer at the cap of the penetrating plume. This provides the primary stage of mixing between plume and environment and exhibits a mixing efficiency around 50 %. Newly generated mixtures of environmental and plume fluid join the intrusion and experience relatively weak turbulence and buoyancy gradients. As the intrusion spreads radially, environmental fluid surrounding the intrusion is mixed into the intrusion with moderate mixing efficiency. This dominates the volume of environmental fluid entrained into the region containing plume fluid. However, the ‘strongest’ entrainment, as measured by the specific entrainment rate, is largest in the plume cap, where the most buoyant environmental fluid is entrained.

One of the things Rosen's very interesting and wide-ranging book shows is why history and the goal of moral advance in history have become so important. We want to believe in moral advance (I am shunning the word “progress” with its resonance of steady uninterrupted forward movement), but we feel incapable of affirming this. What the Lisbon earthquake did to the eighteenth-century versions of Providence, Auschwitz has done for us. Rosen cites Adorno to good effect.

We investigate the role of optimism bias in bull price expectations using incentivized lab-in-the-field experiments with Alabama and Tennessee cattle producers. We develop bull price prediction tasks and reward accurate predictions. We find that the EPD information provision prevents optimism bias from contaminating price expectations in the whole sample. However, we also document that, unlike buyers, sellers are prone to unrealistic optimistic expectations, and our results reveal that optimism bias can be moderated by the type of expected progeny difference information utilized, breed characteristics, and regional differences in cattle operations. We contribute to the literature by documenting the role of behavioral biases.

We estimate a hedonic pricing model to determine producers’ value for bull expected progeny differences (EPDs), genomic-enhanced EPDs, and phenotypic traits. Birth weight EPD, ribeye area EPD, sale weight, age, frame score, and other factors had a statistically significant impact on bull prices. GE-EPDs were not associated with a change in the bull sales prices expect for weaned calf value and birth weight EPDs. Including weaned calf value and GE-EPDs in a bull hedonic pricing model provides a unique contribution. The results from this work will inform educational programming for bull purchasers on using new economic selection indices and GE-EPDs.

The coronavirus disease 2019 (COVID-19) pandemic challenged not only the health-care industry, but also the public health infrastructure in new and wide-ranging ways. Environmental health (EH) professionals have proven to be an essential component of the interdisciplinary public health solution required to prevent, respond, and recover from the COVID-19 pandemic. The Indian Health Service’s Division of Environmental Health Services is a community-based program offering a broad scope of environmental health services and technical assistance. Significant COVID-19 workload activities were recorded from March 2020 through March 2021. A total of 62.7% of the Division’s federal staff completed a 24-question survey in February/March 2021. Primary roles relating to community-based EH, institutional EH, and incident command system support/teams became apparent. Results indicated Division of Environmental Health Services staff provided critical leadership and used their established, trusted, interdisciplinary partnerships to help ensure critical resources and services were available in Indian Country.

Studies were conducted in 2019 and 2020 in Lewiston, NC, to determine the crop response of 4-hydroxyphenylpyrivate dioxygenase (HPPD)-resistant cotton to isoxaflutole (IFT) and other cotton herbicides as part of a cotton weed management program that included herbicides applied preemergence, early postemergence (EPOST), and mid-postemergence (MPOST). IFT was applied PRE at 105 g ha−1 alone and in various combinations with acetochlor, diuron, fluometuron, fluridone, fomesafen, pendimethalin, and pyrithiobac. EPOST treatments included IFT at 53 or 105 g ha−1 alone or in combination with glyphosate or glufosinate, or dimethenamid-P + glufosinate. Glyphosate + glufosinate was applied MPOST to all treatments except the nontreated control. Cotton injury from IFT applied PRE was minimal (0% to 3%). Injury following EPOST application of dimethenamid-P + glufosinate ranged from 3% to 5% and 6% to 9% in 2019 and 2020, respectively. In both years, injury from IFT applied PRE followed by IFT applied EPOST never exceeded injury from IFT applied PRE followed by dimethenamid-P + glufosinate. Isoxaflutole applied PRE followed by IFT applied EPOST at 105 g ha−1 resulted in 0% to 2% cotton injury, indicating that IFT can be applied either PRE or EPOST with minimal risk to cotton. Late-season cotton height and cotton lint yield were not affected by any herbicide treatment. The experimental HPPD-resistant cotton cultivar was minimally injured by IFT applied PRE and EPOST, it tolerated standard cotton herbicides, and yield loss was not observed. Given these results, HPPD-resistant cotton and IFT may be integrated into cotton weed management systems with minimal risk for cotton injury and provide an additional effective mechanism of action for managing troublesome weeds in cotton.

The critical period for weed control (CPWC) adds value to integrated weed management by identifying the period during which weeds need to be controlled to avoid yield losses exceeding a defined threshold. However, the traditional application of the CPWC does not identify the timing of control needed for weeds that emerge late in the critical period. In this study, CPWC models were developed from field data in high-yielding cotton crops during three summer seasons from 2005 to 2008, using the mimic weed, common sunflower, at densities of two to 20 plants per square meter. Common sunflower plants were introduced at up to 450 growing degree days (GDD) after crop planting and removed at successive 200 GDD intervals after introduction. The CPWC models were described using extended Gompertz and logistic functions that included weed density, time of weed introduction, and time of weed removal (logistic function only) in the relationships. The resulting models defined the CPWC for late-emerging weeds, identifying a period after weed emergence before weed control was required to prevent yield loss exceeding the yield-loss threshold. When weeds emerged in sufficient numbers toward the end of the critical period, the model predicted that crop yield loss resulting from competition by these weeds would not exceed the yield-loss threshold until well after the end of the CPWC. These findings support the traditional practice of ensuring weeds are controlled before crop canopy closure, with later weed control inputs used as required.