top-down model


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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.
References in periodicals archive ?
But it is becoming increasingly clear that our top-down model can no longer do justice to taxpayers, public programs, or future generations of Canadians.
A top-down model is essentially a financial/accounting model that starts with actual investments and costs and attempts to make adjustments to reflect a forward-looking approach.
one trajectory of thought asks why the dominant top-down model (modernization theory) in development communication projects failed to improve people's lives in the southern hemisphere.
The top-down model does not reflect recent private-sector management models, which emphasize flat, lean, flexible, team-based organizations.
Grassroots efforts start from the bottom and grow outward while national syndication utilizes a top-down model.
Instead humans are best understood as agents in a social world whose functioning is best understood through a top-down model in which higher level capacities (e.
Also, by having more bottom-up organizing, we're enabling local organizers to rise to positions of leadership much more quickly than with the old top-down model, where you have to wait your turn and "sit in all the chairs," so to speak, before you are given the chance to lead.
And while I have depicted this on a top-down model, in truth this is a cyclical endeavor.
Therefore, this top-down model, Rose suggests, actually sowed the seed for the resurfacing of war-related problems after the 1980s when reconciliation became pluralized and began to incorporate other nongovernmental actors.
Viguier (2005) A Coupled Bottom-up Top-down Model for GHG Abatement Scenarios in the Swiss Housing Sector.
The TGC/Real Clothes movement completely rejects this prior top-down model and realigns fashion standards somewhere between producer and consumer.