576 research outputs found
ESTIMATING NON-PARAMETRIC AND PARAMETRIC TRANSFORMATION FUNCTIONS FROM SURVEY DATA: AN APPLICATION OF MINIMUM CROSS-ENTROPY
A model of a (convex) technology of representative and non-representative firms in a heterogeneous sector is presented in non-parametric and parametric versions. The heterogeneity is specified with error terms. The models including a non-parametric distribution of the errors can be estimated with entropy econometrics from firm survey data. This requires two important modifications in the standard approach to entropy estimation of Golan, Judge and Miller: The compact support of the probability distribution should be designed to capture eventual non-zero covariance. And cross-entropy need to be redefined for cases of multiple observations.Research Methods/ Statistical Methods,
Adsorption of Methanol on Aluminum Oxide: A Density Functional Study
Theoretical calculations based on density functional theory have made
significant contributions to our understanding of metal oxides, their surfaces,
and the binding of molecules at these surfaces. In this paper we investigate
the binding of methanol at the alpha-Al2O3(0001) surface using first-principles
density functional theory. We calculate the molecular adsorption energy of
methanol to be E^g_ads=1.03 eV/molecule. Taking the methanol-methanol
interaction into account, we obtain the adsorption energy E_ads=1.01
eV/molecule. Our calculations indicate that methanol adsorbs chemically by
donating electron charge from the methanol oxygen to the surface aluminum. We
find that the surface atomic structure changes upon adsorption, most notably
the spacing between the outermost Al and O layers changes from 0.11 Angstrom to
0.33 Angstrom.Comment: 11 pages, 3 figures, 1 tabl
FRW Universe Models in Conformally Flat Spacetime Coordinates. I: General Formalism
The 3-space of a universe model is defined at a certain simultaneity. Hence
space depends on which time is used. We find a general formula generating all
known and also some new transformations to conformally flat spacetime
coordinates. A general formula for the recession velocity is deduced.Comment: 12 page
Bianchi Type-I Universe Models with Nonlinear Viscosity
In this paper we study the evolution of spatially homogeneous and anisotropic
Bianchi type-I Universe models with the cosmological constant, \Lambda, and
filled with nonlinear viscous fluid. The dynamical equations for these models
are obtained and solved for some special cases. We calculate the statefinder
parameters for the models and display them in the s-r-plane
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