About the Authors

Corresponding Author

dheidenpea@yahoo.com

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

DH developed the studies, collected and analyzed data, and prepared the manuscript. DW collected and analyzed data and helped revise the manuscript. NF, WRR, and TM analyzed data and helped write the manuscript. BJ, MB, NT, PS, FS, and EL helped with study design and data collection. EG and KS helped develop the studies and helped with data collection. WLD helped prepare the manuscript.