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.
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References in periodicals archive ?
I believe the top-down model challenge, which has so far taken the form of a dialogue between supervisors and banks, could play a greater role in disciplining banks and reducing the incentives for them to systematically underestimate their vulnerabilities.
As this depends on how well the responses of a CGE model would be calibrated to those from a bottom-up model, one can of course not generalize this finding to any generic top-down model. However, this rebuts to some extent the criticism put forward by modelers arguing that the lack of detail in "top-down" CGE models to represent critical features of the power system, especially with respect to large-scale intermittent renewable electricity generation, makes these models an inappropriate tool to study these issues.
Last year, CIBC Economics' top-down model, which is based on a set of macroeconomic, cost and resource market indicators, accurately anticipated a disappointing low, single-digit pace for TSX composite earnings.
In a top-down model, the portfolio intensity is specified without reference to the constituents.
The Clwyd West MP, in an interview with the Conservative Home blog, accused the Welsh Government of presiding over failing health and education systems because ministers are "unreconstructed socialists", adding the health service was based on a "monolithic, top-down model".
This capability trap has been facilitated by four conditions; (i) high expectations on the government without sequencing or prioritization, (ii) more weight on immediate results than on establishing capable institutions, (iii) a limited menu of acceptable options for institutional arrangements, leading to strong pressures for simple 'transplantation', and (iv) a top-down model of implementation.
government to assist such projects, encouraging native initiatives instead of the old top-down model of government assistance.
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.