| 释义 |
Top-Down Model
Top-Down Model (programming)A method for estimating the overall cost andeffort of the proposed software project from global propertiesof the project. The total cost and schedule is partitionedinto components for planning purposes.top-down model
top-down model One of two proposed morphologic pathways of spontaneous development of adenomas. The top-down model is based on observations of dysplastic cells only located at the luminal surface of the crypts, along with migration of adenomatous cells from the surface to the base of a crypt. In this model, an initial stem cell mutation is thought to occur in the epithelial mucosa situated in the intra-cryptal zone between 2 crypt orifices, with subsequent stem cell division producing a mutant clone that expands laterally and downwards into the crypt, displacing normal epithelial cells. |