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.
Individual circadian period (τ) in constant darkness (DD) after a light/dark (LD) cycle without dim light at night against the circadian period in DD after an LD cycle with dim light at night (LDim). Symbols indicate the dim light at night intensity, which had no effect on τ (p = 0.62).
