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.
The hubs are labeled with the corresponding HIV prevalence rates shown in Fig. 1(b). The link thickness and color, ranging from yellow to red, are proportional to the strength of mobility flow. (We used open source QGIS software59 to create maps).
