Factors Affecting the Immune System of the Ornate Box Turtle (\u3ci\u3eTerrapene ornata\u3c/i\u3e)

While many studies have detailed the complex intricacies of the endothermic immune system, relatively little is known about the immune system of ectotherms--specifically, reptiles. In an attempt to gain more knowledge about the factors affecting reptilian immune function, ornate box turtles (Terrapene ornata) were subjected to chronic stress in the form of high ambient temperatures in a semi-natural environment. It was hypothesized that chronic stress would lead to elevated levels of corticosterone in the blood, which would, in turn, suppress immune activity. It was found that body temperature and body mass in particular were significantly affected by chronic heat stress. Among turtles subjected to chronic heat stress, white blood cell to red blood cell ratios decreased and numbers of natural antibodies decreased--all of which suggests lowered immune activity. This decrease in immune activity correlated with increases in body temperature as well as body mass. Changes in corticosterone levels within and between both treatment groups were insignificant. Taken together, these results suggest that turtles subjected to chronic heat stress experienced improved health due to increased body mass, increased body temperature, and decreased immune function. This study reinforces the complexity of the stress response, and it highlights its far-reaching effects not only on immune function, but also on the body as a whole

Youth smoking and anti-smoking policies in North Dakota: a system dynamics simulation study

Background: The current study utilizes system dynamics to model the determinants of youth smoking and simulate effects of anti-smoking policies in the context of North Dakota, a state with one of the lowest cigarette tax rates in the USA. Methods: An explanatory model was built to replicate historical trends in the youth smoking rate. Three different policies were simulated: 1) an increase in cigarette excise taxes; 2) increased funding for CDC-recommended comprehensive tobacco control programs; and 3) enforcement of increased retailer compliance with age restrictions on cigarette sales. Results: The explanatory model successfully replicated historical trends in adolescent smoking behavior in North Dakota from 1992 to 2014. The policy model showed that increasing taxes to $2.20 per pack starting in 2015 was the most effective of the three policies, producing a 32.6% reduction in youth smoking rate by 2032. Other policies reduced smoking by a much lesser degree (7.0 and 3.2% for comprehensive tobacco control program funding and retailer compliance, respectively). The effects of each policy were additive. Conclusions: System dynamics modeling suggests that increasing cigarette excise taxes are particularly effective at reducing adolescent smoking rates. More generally, system dynamics offers an important complement to conventional analysis of observational data.publishedVersio

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Factors Affecting the Immune System of the Ornate Box Turtle (\u3ci\u3eTerrapene ornata\u3c/i\u3e)

While many studies have detailed the complex intricacies of the endothermic immune system, relatively little is known about the immune system of ectotherms--specifically, reptiles. In an attempt to gain more knowledge about the factors affecting reptilian immune function, ornate box turtles (Terrapene ornata) were subjected to chronic stress in the form of high ambient temperatures in a semi-natural environment. It was hypothesized that chronic stress would lead to elevated levels of corticosterone in the blood, which would, in turn, suppress immune activity. It was found that body temperature and body mass in particular were significantly affected by chronic heat stress. Among turtles subjected to chronic heat stress, white blood cell to red blood cell ratios decreased and numbers of natural antibodies decreased--all of which suggests lowered immune activity. This decrease in immune activity correlated with increases in body temperature as well as body mass. Changes in corticosterone levels within and between both treatment groups were insignificant. Taken together, these results suggest that turtles subjected to chronic heat stress experienced improved health due to increased body mass, increased body temperature, and decreased immune function. This study reinforces the complexity of the stress response, and it highlights its far-reaching effects not only on immune function, but also on the body as a whole