The Associations between Physical Activity, Functional Fitness, and Life Satisfaction among Community-Dwelling Older Adults.

Previous studies showed physical activity had benefits for older adults' life satisfaction, but the mechanism was unclear. This study aimed to investigate whether older adults with more physical activity had better functional fitness and life satisfaction, and whether functional fitness mediated the relationship between physical activity and life satisfaction. A cross-sectional study design was employed, and 623 older adults (73.71 ± 5.91 years) were recruited. Physical activity, functional fitness, life satisfaction, and demographic characteristics were collected. Compared with older adults with low physical activity, those with high (B = 0.41, p = 0.025) and moderate (B = 0.40, p = 0.041) physical activity had better life satisfaction; those with high physical activity had better lower limb muscle strength (B = 1.71, p = 0.001), upper (B = 2.91, p = 0.032) and lower (B = 3.12, p = 0.006) limb flexibility, cardiorespiratory endurance (B = 6.65, p = 0.008), and dynamic balance ability (B = −1.12, p < 0.001). Functional fitness did not mediate the relationship between physical activity and life satisfaction. Promoting physical activity may be useful for increasing older adults' functional fitness and life satisfaction, but the effects on functional fitness only occurred at a high level of physical activity, and the effect of physical activity on life satisfaction was not mediated by functional fitness.

COVID-19 and the value of safe transport in the United States.

We investigate the connection between the choice of transportation mode used by commuters and the probability of COVID-19 transmission. This interplay might influence the choice of transportation means for years to come. We present data on commuting, socioeconomic factors, and COVID-19 disease incidence for several US metropolitan areas. The data highlights important connections between population density and mobility, public transportation use, race, and increased likelihood of transmission. We use a transportation model to highlight the effect of uncertainty about transmission on the commuters' choice of transportation means. Using multiple estimation techniques, we found strong evidence that public transit ridership in several US metro areas has been considerably impacted by COVID-19 and by the policy responses to the pandemic. Concerns about disease transmission had a negative effect on ridership, which is over and above the adverse effect from the observed reduction in employment. The COVID-19 effect is likely to reduce the demand for public transport in favor of lower density alternatives. This change relative to the status quo will have implications for fuel use, congestion, accident frequency, and air quality. More vulnerable communities might be disproportionally affected as a result. We point to the need for additional studies to further quantify these effects and to assist policy in planning for the post-COVID-19 transportation future.

Semiellipsoid microlens fabrication method using UV proximity printing.

We present a new semiellipsoid microlens fabrication method that controls the printing gap in the UV lithography process without thermal reflow. The UV proximity printing method can precisely control the curvature radius ratio of the semiellipsoid microlens in the fabrication process. The proposed fabrication method facilitates mass production to achieve a high-yield and high-coupling semiellipsoid microlens that is suitable to be used in commercial fiber transmission systems. A semiellipsoid microlens can be tipped on a single-mode fiber end to improve power coupling efficiency from laser diodes. The semiellipsoid microlens allows increasing the fiber spot size and numerical aperture. It is very important to control the geometric parameters in the assembly procedure to increase the optical coupling efficiency between the laser diode and single-mode fiber. Wide misalignment tolerance, low loss, and low manufacturing cost could be achieved by the proposed fabrication method. The theoretical model is first developed to predict the optical coupling efficiency for various microstructure geometries of semiellipsoid microlens and assembly parameters in this study. Then, the Taguchi method is applied to obtain the optimal geometric parameters setting. The results show that optical coupling efficiency could be significantly improved by using the optimal geometric parameters setting.