Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Rectangles indicate single classification systems BASE, HOUSE, REST, WALK and BICYCLE. Circles indicate single activities VC (vacuuming), SW (sweeping), SI (sitting), LY (lying), ST (standing), WK (walking), RU (running), AS (ascending stairs), DS (descending stairs), BC 50 (bicycling, 50 watt), BC 100 (bicycling, 100 watt), RJ (rope jumping) and WD (washing dishes).
