Adults who are unable to provide initial or on-going consent may participate in this study. When questions arise regarding an adult s ability to provide their own initial or on-going consent, a consultation with the NIH Ability to Consent Assessment Team will be obtained to determine their capacity to consent. In the event that an adult is determined unable to provide initial or on-going consent an appropriate surrogate may provide permission (as per NIH policy M87-4). The subject has the right to discontinue participation or refuse participation in the study at any time without impact to any care or treatment being provided under any other NIH protocol or future participation of a protocol offered at the NIH.