ramp.xds was designed to explore heterogeneous exposure & transmission:
heterogeneous biting rates - differences in the expected number of expected bites, per person, among heterogeneous biting rates: see xds_info_heterogeneous_biting_rates.
environmental heterogeneity - describes variability in the distribution of the number of bites, per person in a homogenous population stratum: see xds_info_environmental_heterogeneity
heterogeneous mixing describes