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.
Spatial distribution of the primary (red) and secondary cases (yellow) detected by nearest-neighbor (A) or uniform-smoothed kernel functions (C). Scatterplots shown the relation between difference time and distance between the secondary outbreak and its primary outbreak, by nearest-neighbor (B) or uniform-smoothed kernel functions (D).
