Before you can start this study, there will be a screening evaluation. The study doctor will review your medical record to find out if you are eligible to take part in this study. Information that will be viewed will include whether you have a skin lesion that might interfere with sensor placement, whether you have a cardiac pacemaker, and/or pregnancy test results. The study doctor will review with you the other types of information that will be viewed from your medical record to find out if you are eligible to take part in this study. For women who are able to have children, if you do not have a negative pregnancy test result in your medical record, you will not be able to take part in this study.