Comparing Online and In-Person Delivery of a Fall Prevention Exercise Program for Older Adults

Exercise is the single most effective strategy to reduce the risk of falls. Online classes have grown in popularity, but the benefits of online classes remain unknown. Zoomers on the Go is a peer-led 12-week exercise program offered twice weekly to adults 50+ years old. The main outcome was lower body strength measured by the 30-s chair stand test. Other outcomes included dropout, attendance, balance, cardiorespiratory fitness, and perceived health. A total of 74 participants (age 66.3 ± 7.1 years) in the online group and 84 participants in the in-person group (age 67.3 ± 7.2 years) completed the program, with attendance for the online group. Both groups significantly improved their 30-s chair stand, cardiorespiratory fitness, and balance (p < .001) with no difference in functional benefits between groups. The in-person group improved their perceived health and significantly reduced levels of stress and depression, while no such changes were observed in the online group.

High dynamic range streak camera for subpicosecond time-resolved x-ray spectroscopy

The full characterization of a time resolved x-ray spectrometer is presented. It is based on the coupling of a conical crystal with a subpicosecond x-ray streak camera. The detector is designed to operate in accumulation mode at high repetition rate (up to 1 kHz) allowing signal to noise ratio as high as 10(4):1. Optical switches have been used to limit the jitter induced in the subpicosecond range, demonstrating the very long term stability (a few hours) of the entire device. The data analysis have been developed to get the spectral and temporal resolution of an ultrashort laser-plasma-based x-ray source.