added basic reproductive number, which I thought I had added in previous version.  Perhaps I forgot to commit it.
added basic reproductive number, which I thought I had added in previous version.  Perhaps I forgot to commit it.
jvd10/apollo,jvd10/apollo,jvd10/apollo,ApolloDev/apollo,jvd10/apollo,ApolloDev/apollo,ApolloDev/apollo,ApolloDev/apollo