Public nature and health for homeless populations: Professionals' perceptions of contingent human benefits and harms.

This article investigates relationships between public nature and health for unsheltered homeless populations. It examines perceptions of health benefits and harms for people living in public natural areas including local, state, and national forests and parks in the Seattle metropolitan area (USA). Interviews with environmental, social service, and law enforcement professionals who regularly interact with this vulnerable population were conducted and thematically analyzed to understand perceptions of physical and mental health outcomes. Results show professionals' perspectives on the health benefits and detriments of time spent in natural environments and the contextual factors perceived to influence health. Interviewees' observations about the variability of personal circumstances and biophysical, social, and weather conditions encourage the nuanced consideration of how contingent therapeutic landscapes provide deeply needed benefits, but for a population with a diminished capacity to adapt when conditions change. We conclude with insights for future research that directly assesses homeless populations' exposures and health outcomes of living in public natural areas.

Short range shooting distance estimation using variable pressure SEM images of the surroundings of bullet holes in textiles.

Modifications of cotton and polyester textiles due to shots fired at short range were analyzed with a variable pressure scanning electron microscope (VP-SEM). Different mechanisms of fiber rupture as a function of fiber type and shooting distance were detected, namely fusing, melting, scorching, and mechanical breakage. To estimate the firing distance, the approximately exponential decay of GSR coverage as a function of radial distance from the entrance hole was determined from image analysis, instead of relying on chemical analysis with EDX, which is problematic in the VP-SEM. A set of backscattered electron images, with sufficient magnification to discriminate micrometer wide GSR particles, was acquired at different radial distances from the entrance hole. The atomic number contrast between the GSR particles and the organic fibers allowed to find a robust procedure to segment the micrographs into binary images, in which the white pixel count was attributed to GSR coverage. The decrease of the white pixel count followed an exponential decay, and it was found that the reciprocal of the decay constant, obtained from the least-square fitting of the coverage data, showed a linear dependence on the shooting distance.