The Effects of Social Stress on Voluntary Running Behavior in Female Mice

Regular physical activity (PA) positively impacts physical and mental health outcomes. However, there is a reciprocal relationship wherein stress significantly reduces healthy levels of routine PA. We showed previously that voluntary running behavior of male mice essentially ceases following exposure to a resident-intruder social stress. Here we examined female mice. Female mice were divided into four groups (n=8/group): sedentary/control, voluntary running/control, sedentary/stress, and voluntary running/stress. Running groups were given unlimited access to a running wheel in the home cage for 9 weeks with a nightly average of 6.86 ± 2.5 km. During the ninth week, stress groups were exposed to a single, 6-hour bout of a female-specific, resident-intruder social stress. Plasma corticosterone significantly increased following stress (34.56 ± 13 ng/ml basal to 330.5 ± 95 ng/ml immediately post-stress). Nightly running dropped significantly to 1.72 ± 0.9 km. Unlike male mice where running levels were slow to recover, voluntary running in these female mice returned to normal levels by the second night (5.01 ± 2.5 km). This study shows the sensitivity of habitual running behavior to stress exposure and suggests the utility of this mouse model in exploring the means by which stress negatively impacts routine PA

Pig Tales: Forensic Taphonomy in Cozine Creek

The medicolegal community relies heavily upon determining the postmortem interval (PMI), the knowledge of how much time has elapsed since the person has died. Forensic taphonomy is the study of postmortem changes caused by outdoor environmental conditions that play a crucial role in decomposition rates. These include local temperatures, humidity, soil, plants, and insect and other scavenger activity. Minimal research exists examining the rate of surface decomposition in the Pacific Northwest climate. The purpose of this pilot study is to analyze the rate of decomposition in the microclimate of McMinnville, Oregon. A deceased juvenile pig (Sus scrofa) was placed in a secure cage in Cozine Creek on February 17, 2019. Data collection continues until May 2019 and includes daily observations, photographs, weather data, and insect collection for entomological assessment. Statistical analysis will be performed once all data is collected. Preliminary results suggest weather fluctuations and insect activity significantly influence decomposition rates. During the first four weeks, cold weather conditions did not favor decomposition: snow, low temperatures, and few insects. Once temperatures reached 13℃, a dramatic increase in insect activity and intensity was observed. Dermestid beetles, maggot masses, and blowflies were present, and within days a substantial increase in decomposition occurred