Heterogeneous population

Heterogeneous landscapes promote population stability.

Habitat heterogeneity is often suggested as being important for the stability of populations, and promoted as a means to aid the conservation of species, but the evidence for such an assumption is poor. Here we show that heterogeneous landscapes that contain a variety of suitable habitat types are associated with more stable population dynamics for 35 British butterfly species from 166 sites. I...

Spreading of disease in heterogeneous population

Stochastic population growth in spatially heterogeneous environments.

Classical ecological theory predicts that environmental stochasticity increases extinction risk by reducing the average per-capita growth rate of populations. For sedentary populations in a spatially homogeneous yet temporally variable environment, a simple model of population growth is a stochastic differential equation dZ(t) = μZ(t)dt + σZ(t)dW(t), t ≥ 0, where the conditional law of Z(t+Δt)-...

Optimal Rationing within a Heterogeneous Population

A government agency delegates to a provider (hospital, medical gatekeeper, school, social worker) the decision to supply a service or treatment to individual recipients. The agency does not perfectly know the distribution of individual treatment costs in the population. The single-crossing property is not satisfied when the uncertainty pertains to the dispersion of the distribution. We find tha...

Th2-high asthma: a heterogeneous asthma population?

Results Cubic Clustering Criterion, pseudo F and t statistics revealed a twoand a six-cluster model. The first cluster (n=23) was found in both models and consists of patients who present with an “IL-5-high and IL-17F-high” profile. Patients with an “IL-4or IL-13-high” profile did not cluster in one single group. In the six-cluster model, the “IL-17F-low” group was divided into 5 separate clust...