Here we develop an explicitly covariant expression for the stationary phase approximation of a classical partition function based on geometric properties of the phase space. As an example of the utility of such an evaluation we show that in the case of the Hamiltonian ows generating conformal rescalings of the underlying geometry, the classical partition function is given exactly by the leading...

Section 5.2 of this book decries the decline in the understanding of structural equation modeling in econometric in the past three decades (see also Hoover 2003, “Lost Causes”) and attributes this decline to a careless choice of notation which blurred the essential distinction between algebraic and structural equations. In a series of articles (Heckman 2000, 2003, 2005; Heckman and Vytlacil 200...

Using recent econometric developments about causal inference, I examine whether diversification destroys value. I estimate the value effect of diversification by matching diversifying and single-segment firms on their propensity score-the predicted values from a probit model of the propensity to diversify. I also use Heckman 's (1979) two-stage estimator for comparison purposes. Ifind that on a...

This study assessed the determinants of intensity of improved rice varieties adoption using the Tobit model and also employed. The Heckman Two-stage model was used to identify the determinants of market participation and its potential impact on farming households’ welfare in three states selected from the three notable rice producing ecologies in Nigeria. A crosssectional data of 600 rice farme...

Materials and methods A Binary Probit model ws used to measure the participation in work force and a two-stage Heckman model to measure worked h and productivity. Each model is estimated separately for both gender individuals, with and without disease, according three distinct definitions for DM: Restrict, Broad and Comorbidities. To capture the counterfactual effect, the model was calculated f...