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.

Introduction: The legalization of cannabis for recreational use in 2018 remains a controversial topic. There are multiple perceived benefits of cannabis including pain relief, treatment of epilepsy syndromes, and improving body weight of cancer patients. However, there are also many potential risks. The short-term health consequences include cannabinoid hyperemesis syndrome and cannabis induced psychosis. These conditions directly impact the influx of patients presenting to Emergency Departments (ED). There is currently limited research in the area of cannabis legalization burden. However, the studies performed have shown a significant impact in those states which cannabis is legal. A study completed in Colorado found that hospitalization rates with marijuana related billing codes increased from 274 to 593 per 100 000 hospitalizations after the state legalization of recreational cannabis. This study aims to examine if Canada's hospitals are experiencing the same burden as other jurisdictions. Methods: A descriptive study was preformed via a retrospective chart review of cannabis related visits in tertiary EDs in St. John's, NL, from six months prior to the date of legalization of cannabis for recreational use, to six months after. Hospital ED visit records from both the Health Science Centre and St. Clare's Mercy Hospital were searched using keywords to identify patients who presented with symptoms related to cannabis use. We manually reviewed all visit records that included one or more of these terms to distinguish true positives from false positive cases, unrelated to cannabis use. Results: A total of 287 charts were included in the study; 123 visits were related to cannabis use six months prior to legalization, and 164 six months after legalization. A significant increase in ED visits following the legalization of recreational cannabis was seen (p < .001). There was no significant difference in the age of users between the two groups. Additionally, the number one presenting complaint due to cannabis use was vomiting (47.7%), followed by anxiety (12.2%). Conclusion: Following the implementation of the Cannabis Act in Canada, EDs in St. John's, NL had a statistically significant increase in the number of visits related to cannabis use. It is important to determine such consequences to ensure hospitals and public health agencies are prepared to treat the influx of visits and are better equipped to manage the associated symptoms.

Tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} at 2 or 4 ppmw placed 0 to 3, 8 to 11, or 15 to 18 cm deep in soil columns reduced root and shoot weights of buffelgrass [Pennisetum ciliare (L.) Link # PESCI] 30 days after emergence. Plains bristlegrass (Setaria macrostachya H.B.K.) seedling shoot weights were not reduced when 2 ppmw tebuthiuron was placed 8 to 11 cm deep or deeper. Effects of tebuthiuron at 0.13 to 0.50 ppmw on buffelgrass shoot and net tiller production were not moderated by the presence of honey mesquite (Prosopis glandulosa # PRCJG) in the pots. However, regardless of tebuthiuron dosage, average height and shoot weight of buffelgrass seedlings were greater when seedlings were grown in soil collected from beneath honey mesquite canopies compared to growth in soil from interspaces. Therefore, spatial variations in buffelgrass response to applications of tebuthiuron for control of invading shrubs may largely be attributed to soil changes induced by woody plants rather than to presence of shrubs.

We compare first-order (refractive) ionospheric effects seen by the MWA with the ionosphere as inferred from GPS data. The first-order ionosphere manifests itself as a bulk position shift of the observed sources across an MWA field of view. These effects can be computed from global ionosphere maps provided by GPS analysis centres, namely the CODE. However, for precision radio astronomy applications, data from local GPS networks needs to be incorporated into ionospheric modelling. For GPS observations, the ionospheric parameters are biased by GPS receiver instrument delays, among other effects, also known as receiver DCBs. The receiver DCBs need to be estimated for any non-CODE GPS station used for ionosphere modelling. In this work, single GPS station-based ionospheric modelling is performed at a time resolution of 10 min. Also the receiver DCBs are estimated for selected Geoscience Australia GPS receivers, located at Murchison Radio Observatory, Yarragadee, Mount Magnet and Wiluna. The ionospheric gradients estimated from GPS are compared with that inferred from MWA. The ionospheric gradients at all the GPS stations show a correlation with the gradients observed with the MWA. The ionosphere estimates obtained using GPS measurements show promise in terms of providing calibration information for the MWA.

GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination + 25° at frequencies between 72 and 231 MHz, made with the MWA using a drift scan method that makes efficient use of the MWA’s very large field-of-view. We present the observation details, imaging strategies, and theoretical sensitivity for GLEAM. The survey ran for two years, the first year using 40-kHz frequency resolution and 0.5-s time resolution; the second year using 10-kHz frequency resolution and 2 s time resolution. The resulting image resolution and sensitivity depends on observing frequency, sky pointing, and image weighting scheme. At 154 MHz, the image resolution is approximately 2.5 × 2.2/cos (δ + 26.7°) arcmin with sensitivity to structures up to ~ 10° in angular size. We provide tables to calculate the expected thermal noise for GLEAM mosaics depending on pointing and frequency and discuss limitations to achieving theoretical noise in Stokes I images. We discuss challenges, and their solutions, that arise for GLEAM including ionospheric effects on source positions and linearly polarised emission, and the instrumental polarisation effects inherent to the MWA’s primary beam.

A 28-year-old woman presented with a one day history of high fever and partial seizures with secondary generalization. This was preceded by a three week history of headache, ataxia, and fatigue. An initial computed tomogram head scan showed a low density mass lesion in the right frontal operculum without enhancement. On the next day, a repeat scan showed a new frontopolar, expansile, low density cortical lesion (Figure 1A) suggestive of encephalitis. Cerebrospinal fluid showed a pleocytosis of 311 mononuclear white blood cell count per μL and an elevated protein of 1.57 g/L. She received intravenous acyclovir and antibiotics. She remained febrile and became mute. A magnetic resonance (MR) scan under general anesthesia on her fourth hospital day showed frontal and perisylvian lesions with restricted diffusion (Figure 1B - D and Figure 2). A right frontal brain biopsy showed meningoencephalitis and immunohistochemical staining was positive for herpes simplex virus (HSV) antigen (Figure 3). Subsequently, HSV-1 DNA was demonstrated in both cerebrospinal fluid and brain tissue with polymerase chain amplification. She improved after a course of intravenous therapy with acyclovir with residual frontal lobe signs, including marked executive dysfunction, and her speech became normal.