An ERD (Entity Relationship Diagram) is a graphical representation of the data in rest within a system (e.g. a business, an organization, an application) that is subject to analysis.
1. REFERENCE DOSE (RfD): DESCRIPTION AND USE IN HEALTH RISK ASSESSMENTS. 1.1. INTRODUCTION. This concept paper describes the U.S. Environmental Protection Agency's (U.S. EPA) principal approach to and rationale for assessing risk for health effects other than cancer and gene mutations from chronic chemical exposure.
Rural Free Delivery: Rural Free Delivery (RFD), service begun in the United States in 1896 to deliver mail directly to farm families. Before RFD, rural inhabitants had to pick up mail themselves at sometimes distant post offices or pay private express companies for delivery.