The U.S. Department of Agriculture–Agricultural Research Service (USDA-ARS) has been a leader in weed science research covering topics ranging from the development and use of integrated weed management (IWM) tactics to basic mechanistic studies, including biotic resistance of desirable plant communities and herbicide resistance. ARS weed scientists have worked in agricultural and natural ecosystems, including agronomic and horticultural crops, pastures, forests, wild lands, aquatic habitats, wetlands, and riparian areas. Through strong partnerships with academia, state agencies, private industry, and numerous federal programs, ARS weed scientists have made contributions to discoveries in the newest fields of robotics and genetics, as well as the traditional and fundamental subjects of weed–crop competition and physiology and integration of weed control tactics and practices. Weed science at ARS is often overshadowed by other research topics; thus, few are aware of the long history of ARS weed science and its important contributions. This review is the result of a symposium held at the Weed Science Society of America’s 62nd Annual Meeting in 2022 that included 10 separate presentations in a virtual Weed Science Webinar Series. The overarching themes of management tactics (IWM, biological control, and automation), basic mechanisms (competition, invasive plant genetics, and herbicide resistance), and ecosystem impacts (invasive plant spread, climate change, conservation, and restoration) represent core ARS weed science research that is dynamic and efficacious and has been a significant component of the agency’s national and international efforts. This review highlights current studies and future directions that exemplify the science and collaborative relationships both within and outside ARS. Given the constraints of weeds and invasive plants on all aspects of food, feed, and fiber systems, there is an acknowledged need to face new challenges, including agriculture and natural resources sustainability, economic resilience and reliability, and societal health and well-being.

Protoporphyrinogen oxidase (PPO)-inhibiting herbicides remain an important and useful chemistry 60 yr after their first introduction. In this review, based on topics introduced at the Weed Science Society of America 2021 symposium titled “A History, Overview, and Plan of Action on PPO Inhibiting Herbicides,” we discuss the current state of PPO-inhibiting herbicides. Renewed interest in the PPO-inhibiting herbicides in recent years, due to increased use and increased cases of resistance, has led to refinements in knowledge regarding the mechanism of action of PPO inhibitors. Herein we discuss the importance of the two isoforms of PPO in plants, compile a current knowledge of target-site resistance mechanisms, examine non–target site resistance cases, and review crop selectivity mechanisms. Consistent and reproducible greenhouse screening and target-site mutation assays are necessary to effectively study and compare PPO-inhibitor resistance cases. To this end, we cover best practices in screening to accurately identify resistance ratios and properly interpret common screens for point mutations. The future of effective and sustainable PPO-inhibitor use relies on development of new chemistries that maintain activity on resistant biotypes and the promotion of responsible stewardship of PPO inhibitors both new and old. We present the biorational design of the new PPO inhibitor trifludimoxazin to highlight the future of PPO-inhibitor development and discuss the elements of sustainable weed control programs using PPO inhibitors, as well as how responsible stewardship can be incentivized. The sustained use of PPO inhibitors in future agriculture relies on the effective and timely communication from mode of action and resistance research to agronomists, Extension workers, and farmers.

The purpose of this study was to enrich parrot enclosures by creating foraging opportunities appropriate for the species and to investigate the possible preference for a variable versus a constant food supply. The foraging device comprised of a length of wood (2×0.08×0.08m) with 50 holes (0.02m diameter x 0,02m depth) drilled into one face. Food was placed in the holes of the foraging device in one of two distributions: ‘constant’, one food item in every hole (total = 50 food items) or ‘variable’, 5 food items in 10 of the holes (total = 50 food items). The holes were then covered with starch paper. During the enrichment period the parrots spent significantly more time allopreening than in the baseline or post-enrichment periods. The results also provide some evidence of contrafreeloading in parrots, but no preference for a variable over a constant food source. The study shows that providing extra foraging opportunities for parrots is a useful form of enrichment.

Over the last 25 years, radiowave detection of neutrino-generated signals, using cold polar ice as the neutrino target, has emerged as perhaps the most promising technique for detection of extragalactic ultra-high energy neutrinos (corresponding to neutrino energies in excess of 0.01 Joules, or 1017 electron volts). During the summer of 2021 and in tandem with the initial deployment of the Radio Neutrino Observatory in Greenland (RNO-G), we conducted radioglaciological measurements at Summit Station, Greenland to refine our understanding of the ice target. We report the result of one such measurement, the radio-frequency electric field attenuation length $L_\alpha$. We find an approximately linear dependence of $L_\alpha$ on frequency with the best fit of the average field attenuation for the upper 1500 m of ice: $\langle L_\alpha \rangle = ( ( 1154 \pm 121) - ( 0.81 \pm 0.14) \, ( \nu /{\rm MHz}) ) \,{\rm m}$ for frequencies ν ∈ [145 − 350] MHz.

Seed retention, and ultimately seed shatter, are extremely important for the efficacy of harvest weed seed control (HWSC) and are likely influenced by various agroecological and environmental factors. Field studies investigated seed-shattering phenology of 22 weed species across three soybean [Glycine max (L.) Merr.]-producing regions in the United States. We further evaluated the potential drivers of seed shatter in terms of weather conditions, growing degree days, and plant biomass. Based on the results, weather conditions had no consistent impact on weed seed shatter. However, there was a positive correlation between individual weed plant biomass and delayed weed seed–shattering rates during harvest. This work demonstrates that HWSC can potentially reduce weed seedbank inputs of plants that have escaped early-season management practices and retained seed through harvest. However, smaller individuals of plants within the same population that shatter seed before harvest pose a risk of escaping early-season management and HWSC.

Influenza vaccine effectiveness (VE) wanes over the course of a temperate climate winter season but little data are available from tropical countries with year-round influenza virus activity. In Singapore, a retrospective cohort study of adults vaccinated from 2013 to 2017 was conducted. Influenza vaccine failure was defined as hospital admission with polymerase chain reaction-confirmed influenza infection 2–49 weeks after vaccination. Relative VE was calculated by splitting the follow-up period into 8-week episodes (Lexis expansion) and the odds of influenza infection in the first 8-week period after vaccination (weeks 2–9) compared with subsequent 8-week periods using multivariable logistic regression adjusting for patient factors and influenza virus activity. Records of 19 298 influenza vaccinations were analysed with 617 (3.2%) influenza infections. Relative VE was stable for the first 26 weeks post-vaccination, but then declined for all three influenza types/subtypes to 69% at weeks 42–49 (95% confidence interval (CI) 52–92%, P = 0.011). VE declined fastest in older adults, in individuals with chronic pulmonary disease and in those who had been previously vaccinated within the last 2 years. Vaccine failure was significantly associated with a change in recommended vaccine strains between vaccination and observation period (adjusted odds ratio 1.26, 95% CI 1.06–1.50, P = 0.010).

Potential effectiveness of harvest weed seed control (HWSC) systems depends upon seed shatter of the target weed species at crop maturity, enabling its collection and processing at crop harvest. However, seed retention likely is influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed-shatter phenology in 13 economically important broadleaf weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to 4 wk after physiological maturity at multiple sites spread across 14 states in the southern, northern, and mid-Atlantic United States. Greater proportions of seeds were retained by weeds in southern latitudes and shatter rate increased at northern latitudes. Amaranthus spp. seed shatter was low (0% to 2%), whereas shatter varied widely in common ragweed (Ambrosia artemisiifolia L.) (2% to 90%) over the weeks following soybean physiological maturity. Overall, the broadleaf species studied shattered less than 10% of their seeds by soybean harvest. Our results suggest that some of the broadleaf species with greater seed retention rates in the weeks following soybean physiological maturity may be good candidates for HWSC.

Seed shatter is an important weediness trait on which the efficacy of harvest weed seed control (HWSC) depends. The level of seed shatter in a species is likely influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter of eight economically important grass weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to 4 wk after maturity at multiple sites spread across 11 states in the southern, northern, and mid-Atlantic United States. From soybean maturity to 4 wk after maturity, cumulative percent seed shatter was lowest in the southern U.S. regions and increased moving north through the states. At soybean maturity, the percent of seed shatter ranged from 1% to 70%. That range had shifted to 5% to 100% (mean: 42%) by 25 d after soybean maturity. There were considerable differences in seed-shatter onset and rate of progression between sites and years in some species that could impact their susceptibility to HWSC. Our results suggest that many summer annual grass species are likely not ideal candidates for HWSC, although HWSC could substantially reduce their seed output during certain years.

Magnetic field-assisted freeze-casting of porous alumina structures is reported. Different freeze-casting parameters were investigated and include the composition of the original slurry (Fe3O4 and PVA content) and the control of temperature during the free casting process. The optimum content of the additives in the slurry were 3 and 6 wt% for PVA and Fe3O4, respectively. These conditions provided the most unidirectional porous structures throughout the length of the sample. The sintering temperature was maintained at 1500 °C for 3 h. The application of a vertical magnetic field (parallel to ice growth direction) with using a cooling rate mode technique was found to enhance the homogeneity of the porous structure across the sample. The current study suggests that magnetic field-assisted freeze-casting is a viable method to create highly anisotropic porous ceramic structures.

Field studies were conducted in 2018 and 2019 in Arkansas, Indiana, Illinois, Missouri, and Tennessee to determine if cover-crop residue interfered with herbicides that provide residual control of Palmer amaranth and waterhemp in no-till soybean. The experiments were established in the fall with planting of cover crops (cereal rye + hairy vetch). Herbicide treatments consisted of a nontreated or no residual, acetochlor, dimethenamid-P, flumioxazin, pyroxasulfone + flumioxazin, pendimethalin, metribuzin, pyroxasulfone, and S-metolachlor. Palmer amaranth took 18 d and waterhemp took 24 d in the cover crop–alone (nontreated) treatment to reach a height of 10 cm. Compared with this treatment, all herbicides except metribuzin increased the number of days until 10-cm Palmer amaranth was present. Flumioxazin applied alone or in a mixture with pyroxasulfone were the best at delaying Palmer amaranth growing to a height of 10 cm (35 d and 33 d, respectively). The herbicides that resulted in the lowest Palmer amaranth density (1.5 to 4 times less) integrated with a cover crop were pyroxasulfone + flumioxazin, flumioxazin, pyroxasulfone, and acetochlor. Those four herbicide treatments also delayed Palmer amaranth emergence for the longest period (27 to 34 d). Waterhemp density was 7 to 14 times less with acetochlor than all the other herbicides present. Yield differences were observed for locations with waterhemp. This research supports previous research indicating that utilizing soil-residual herbicides along with cover crops improves control of Palmer amaranth and/or waterhemp.

Selenium (Se) is an essential element for human health. However, our knowledge of the prevalence of Se deficiency is less than for other micronutrients of public health concern such as iodine, iron and zinc, especially in sub-Saharan Africa (SSA). Studies of food systems in SSA, in particular in Malawi, have revealed that human Se deficiency risks are widespread and influenced strongly by geography. Direct evidence of Se deficiency risks includes nationally representative data of Se concentrations in blood plasma and urine as population biomarkers of Se status. Long-range geospatial variation in Se deficiency risks has been linked to soil characteristics and their effects on the Se concentration of food crops. Selenium deficiency risks are also linked to socio-economic status including access to animal source foods. This review highlights the need for geospatially-resolved data on the movement of Se and other micronutrients in food systems which span agriculture–nutrition–health disciplinary domains (defined as a GeoNutrition approach). Given that similar drivers of deficiency risks for Se, and other micronutrients, are likely to occur in other countries in SSA and elsewhere, micronutrient surveillance programmes should be designed accordingly.

Evidence on whether nutritional supplementation affects physical activity (PA) during early childhood is limited. We examined the long-term effects of lipid-based nutrient supplements (LNS) on total PA, moderate-to-vigorous PA (MVPA) and sedentary behaviour (SB) of children at 4–6 years using an accelerometer for 1 week. Their mothers were enrolled in the International Lipid-based Nutrient Supplement-DYAD randomised controlled trial in Ghana, assigned to daily LNS or multiple micronutrients (MMN) during pregnancy through 6 months postpartum or Fe and folic acid (IFA) during pregnancy and placebo for 6 months postpartum. From 6 to 18 months, children in the LNS group received LNS; the other two groups received no supplements. Analysis was done with intention to treat comparing two groups: LNS v. non-LNS (MMN+ IFA). Of the sub-sample of 375 children fitted with accelerometers, 353 provided sufficient data. Median vector magnitude (VM) count was 1374 (interquartile range (IQR) 309), and percentages of time in MVPA and SB were 4·8 (IQR 2) and 31 (IQR 8) %, respectively. The LNS group (n 129) had lower VM (difference in mean −73 (95 % CI −20, −126), P = 0·007) and spent more time in SB (LNS v. non-LNS: 32·3 v. 30·5 %, P = 0·020) than the non-LNS group (n 224) but did not differ in MVPA (4·4 v. 4·7 %, P = 0·198). Contrary to expectations, provision of LNS in early life slightly reduced the total PA and increased the time in SB but did not affect time in MVPA. Given reduced social-emotional difficulties in the LNS group previously reported, including hyperactivity, one possible explanation is less restless movement in the LNS group.