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Strongly polyphenic social insects provide excellent models to examine the neurobiological basis of division of labor. Turtle ants, Cephalotes varians, have distinct minor worker, soldier, and reproductive (gyne/queen) morphologies associated with their behavioral profiles: small-bodied task-generalist minors lack the phragmotic shield-shaped heads of soldiers, which are specialized to block and guard the nest entrance. Gynes found new colonies and during early stages of colony growth overlap behaviorally with soldiers. Here we describe patterns of brain structure and synaptic organization associated with division of labor in C. varians minor workers, soldiers, and gynes. We quantified brain volumes, determined scaling relationships among brain regions, and quantified the density and size of microglomeruli, synaptic complexes in the mushroom body calyxes important to higher-order processing abilities that may underpin behavioral performance. We found that brain volume was significantly larger in gynes; minor workers and soldiers had similar brain sizes. Consistent with their larger behavioral repertoire, minors had disproportionately larger mushroom bodies than soldiers and gynes. Soldiers and gynes had larger optic lobes, which may be important for flight and navigation in gynes, but serve different functions in soldiers. Microglomeruli were larger and less dense in minor workers; soldiers and gynes did not differ. Correspondence in brain structure despite differences in soldiers and gyne behavior may reflect developmental integration, suggesting that neurobiological metrics not only advance our understanding of brain evolution in social insects, but may also help resolve questions of the origin of novel castes., Competing Interests: The authors have declared that no competing interests exist.

Unmanned aircraft, or drones, are a rapidly emerging sector of the aviation industry. There has been limited substantive research, however, into the public perception and acceptance of drones. This article presents the results from two surveys of the Australian public designed to investigate (1) whether the public perceive drones to be riskier than existing manned aviation, (2) whether the terminology used to describe the technology influences public perception, and (3) what the broader concerns are that may influence public acceptance of the technology. We find that the Australian public currently hold a relatively neutral attitude toward drones. Respondents did not consider the technology to be overly unsafe, risky, beneficial, or threatening. Drones are largely viewed as being of comparable risk to that of existing manned aviation. Furthermore, terminology had a minimal effect on the perception of the risks or acceptability of the technology. The neutral response is likely due to a lack of knowledge about the technology, which was also identified as the most prevalent public concern as opposed to the risks associated with its use. Privacy, military use, and misuse (e.g., terrorism) were also significant public concerns. The results suggest that society is yet to form an opinion of drones. As public knowledge increases, the current position is likely to change. Industry communication and media coverage will likely influence the ultimate position adopted by the public, which can be difficult to change once established., (© 2014 Society for Risk Analysis.)

Background: Long-term mechanical ventilation is considered as a relative or absolute contraindication for lung transplantation by most centers. We report on the results of transplantation in nine patients requiring long-term mechanical ventilation at two lung transplant centers., Methods: The study group (group 1) consisted of nine patients receiving mechanical ventilation who underwent lung transplantation at either Duke University Medical Center or the University of Florida between 1992 and 1997. Patients in group 1 met the following criteria: they underwent exercise therapy with a physical therapist, and they were without panresistant bacterial airway colonization. The study patients that met these criteria spent at least 13 days receiving mechanical ventilation prior to transplantation. The control population (group 2; n = 65) consisted of all patients who underwent transplantation at either center in the calendar year 1997 who were ventilator independent. The 1-year survival rates in each group were calculated by the Kaplan-Meier method. The number of days required for extubation in each group were compared by the nonparametric Wilcoxon rank sum test. The FEV(1) value at 1 year was reported in each group., Results: The 1-year survival rates were 78% and 83% in group 1 and group 2, respectively. The mean number of days required until extubation were 41 days in group 1 and 9 days in group 2 (p < 0.01). The allograft function was comparable in the two groups at 1 year., Conclusions: In a select population of ventilator-dependent patients, the 1-year survival rate is comparable to the standard lung transplant population. However, these ventilator-dependent patients require a significantly longer time until extubation than other transplant recipients.