There is, however, evidence for close genetic ties between distally located sample locations, indicating that movement of malaria parasites and flow of genes is being driven by factors other than distance decay.
The sample can be intensified in areas of interest by further tesselating existing hexagons into finer spatial units, each with a randomly located sample.
This sample design, in which one arbitrarily located sample point is drawn from equal-area sample units distributed across the landscape, is similar to that used by FIA, and our estimate of biomass density in the state of California closely matched FIA's design-based estimate.
Secondly, the number of households living in the area was recorded; the located sample size for each kebeles was obtained using probability proportional to the size of households found in each kebele.
A search by sample is done using the EarthScope SAFOD Core Viewer that allows a user to locate samples on high resolution images of core sections belonging to different runs and holes.
By locating samples in the probabilistic most probable region, only a small number of samples are used to build a precise surrogate model in the end, and only a few actual limit state function evaluations are required correspondingly.
It was necessary to locate samples that had been buried in cool and dry conditions, under which DNA is degraded relatively slowly.
Of the original 925 included subjects in the cohort, we could not locate samples in the biobank for 60 subjects, and 220 had insufficient volume for PFOS measurements.
The member biobank maintains the legal custodianship of samples, whereas the EBB acts as a clearing house or 'virtual' biobank with its online catalogue and search engine for locating samples.
