Intraregional Migration- Historical Precedents
(Regional Strategy and Project Proposals).
The main components of the regional system are a physical subsystem composed of natural resources and infrastructural components; an activity subsystem composed of social and economic components; and a regulating subsystem composed of institutions and technological components.
Regional development, programs, and projects.
In most of the models, point-source parameter estimates were both highly significant in accounting for the spatial pattern in water quality and close to expected values based on the functional form of the model. In most cases, the statistical significance levels (i.e., “p-values”) for point sources were ≤0.004, which indicates the strong statistical relationship between estimates of point-source nutrient contributions and downstream loads. Theoretically, point-source coefficient estimates should approximate the value 1, because point sources (quantified as mass per time) discharge directly to streams without the potential for land-based attenuation (). The regional model point-source coefficient estimates range approximately from 0.67 to 1.9, with only 3 of the 12 models (1 TN and 2 TP) indicating a mean value that is statistically different from the expected value of 1 (based on a two-tailed t-test for α = 0.05). Point-source coefficient estimates that are higher or lower than expected likely result from inaccurately estimated point-source contributions, which are empirically adjusted by the model to best match the observed stream loads. The available point-source data derived from the U.S. Environmental Protection Agency (USEPA) Permit Compliance System (PCS) database must often be estimated due to lack of reporting, thus potentially causing lower accuracy and precision in the SPARROW prediction of point-source contributions to the stream nutrient load (). Models with coefficient values