Underwater sound of three unoccupied aerial vehicles at varying altitudes and horizontal distances.

Unoccupied aerial vehicles (UAVs), or "drones," are increasingly used as a tool for cetacean research, but knowledge about how these tools contribute to underwater sound is lacking. In this study, underwater sound levels of three commonly used UAV models (Mavic Pro Platinum, Phantom 4 Pro v2.0, Inspire 1 Pro) were recorded. For each model, three replicate flights were conducted at 36 positions at standardized horizontal (0-30 m) and vertical (2-40 m) distances from a hydrophone (1 m depth). Median broadband received levels of the Inspire were highest at 96.5 dBrms 141-17 783 Hz re 1 µPa2, followed by the Phantom (92.4 dBrms 141-17 783 Hz re 1 µPa2) and Mavic, which was quietest (85.9 dBrms 141-17 783 Hz re 1 µPa2). Median ambient sound levels in the absence of an UAV were 82.7 dBrms 141-17 783 Hz re 1 µPa2. Significant increases in ambient sound levels associated with UAV flights occurred at higher altitudes than previously reported, and received levels decreased more with increasing horizontal distance of the UAV than with altitude. To minimize potential noise impacts on sensitive marine animal subjects, we recommend increasing horizontal distance to the animal, rather than altitude, and choosing the quietest UAV feasible.

Gender Differences in Medical Cannabis Use: Symptoms Treated, Physician Support for Use, and Prescription Medication Discontinuation.

Background: Medical cannabis (MC) utilization continues to expand in the United States, as a growing body of evidence supports the use of cannabis and cannabinoids in the treatment of a range of chronic conditions. To date, gender-related differences in MC use are not widely reported, and little is known regarding physicians' support of patients' use of MC to address symptoms associated with chronic conditions. Materials and Methods: We conducted a cross-sectional online survey of MC users in Illinois (n = 361). We summarized participants' qualifying conditions, symptoms treated with MC, perceived physician support for MC use, use of MC and prescription medications, then analyzed differences by participant gender. Results: Bivariate analyses indicate that men report higher levels of support for MC use from both specialist and primary care physicians. Women were significantly more likely to increase use of cannabis after acquiring an MC card, and to discontinue prescription medications through MC use. Multivariable analyses indicate that being a woman, using MC to treat multiple symptoms, and reporting higher levels of support for MC use from a primary care provider significantly increased the likelihood of discontinuing prescription medication through MC use. Discussion: Women are more likely to report decreased use of prescription medications to treat symptoms, and report lower levels of support from physicians for MC use. Future research on gender differences in this population may benefit from more detailed data related to symptomology, utilization, dosing, and outcomes associated with MC, and interactions with the health care system to extend these findings.