Fernandez et al. Respond to "Natural Versus Unnatural Sex Ratios"

Reeves et al. Respond to “Harnessing Housing Natural Experiments”

We appreciate the interest our study (1), which took advantage of a natural experiment design to better ascertain causality than conventional observational studies could, has generated. In their accompanying commentary, Bentley et al. (2) suggest that misclassification of depression symptoms (e.g., someone with depression reporting that they are not depressed) may explain our findings if miscla...

Clayton et al. respond.

Lusk et al. respond.

We thank Schimek for his thoughtful letter. We agree that the American Association of State Highway and Transportation Officials (AASHTO) encourages bike paths; however, AASHTO’s definition of a bike path is a shared use path for pedestrians, skaters, wheelchair users, joggers, and other nonmotorized users. AASHTO discourages bicycle-only cycle tracks because, as noted by Schimek, AASHTO discou...

Birth Outcomes and Natural Gas Development: McKenzie et al. Respond

Nanotoxicology: Gangwal et al. Respond

Gangwal et al. (2011) addressed an important topic for nanotoxicology about assessing the toxicity of inhaled nano materials by recom mending relevant concentrations for in vitro toxicity testing. Their efforts to select in vitro concentrations based on reported occupational exposure levels of inhaled nano materials are, indeed, laudable. Their under lying conceptual approach is logical, involv...