Home  About us  Contact
 

Theoretical Methodology (theoretical + methodology)

Distribution by Scientific Domains
Business, Economics, Finance and Accounting50%

Selected Abstracts

Modeling and Measuring Productivity in the Agri-Food Sector: Trends, Causes and Effects

CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2000
Catherine J. Morrison Paul
This article overviews recent trends in modeling and measuring productivity patterns, and in distinguishing their determinants and implications, for the agri-food sector. Theoretical methodologies as well as empirical implementation and results are discussed, with a view toward identifying those with potential for facilitating understanding of productivity measures, and ultimately using them for policy guidance. Productivity growth evidence for the food systems of the U.S., Canada and the U.K. is summarized, and recent studies distinguishing underlying causes of production structure patterns and linking them with market-structure patterns are reviewed, as a basis for assessing the key messages from and trends in this literature. L'auteurfait un survol de révolution récente dans les domaines de la modélisation et de la mesure des courbes de productivité ainsi que de la caractérisation de leurs determinants et de leurs significations pour le secteur agroalimentaire. Il passe en revue les méthodes théoriques aussi bien que les applications empiriques et leurs résultats afin d'en dégager ceux qui pourraient faciliter la comprehension des mesures de la productivité et qui, éventuellement, pourraient servir de guide awe décideurs. L'auteur analyse les signes de croissance de la productivité des filières agroalimentaires observés aux Etats-Unis, au Canada et au Royaume-Uni. Enfln il examine les études récentes sur les causes sous-jacentes des évolutions des structures de production et sur leurs liens avec l'évolution des structures de marché, dans le but d'en dégager les messages et les tendances dés. [source]

Enhanced Two-Photon Absorption of Organic Chromophores: Theoretical and Experimental Assessments,

ADVANCED MATERIALS, Issue 24 2008
Francesca Terenziani
Abstract Functional organic materials with enhanced two-photon absorption lead to new technologies in the fields of chemistry, biology, and photonics. In this article we review experimental and theoretical methodologies allowing detailed investigation and analysis of two-photon absorption properties of organic chromophores. This includes femtosecond two-photon excited fluorescence experimental setups and quantum-chemical methodologies based on time-dependent density functional theory. We thoroughly analyze physical phenomena and trends leading to large two-photon absorption responses of a few series of model chromophores focusing on the effects of symmetric and asymmetric donor/acceptor substitution and branching. [source]

Capital Equalization and the Australian States

THE ECONOMIC RECORD, Issue 232 2000
JEFFREY PETCHEY
The Australian Grants Commission has recently considered ways to take account of differences in capital costs across States within the existing fiscal equalization formula. Here we develop a theoretical methodology for estimating differences in the costs of capital faced by the States in the General Government Sector. This methodology is used to generate preliminary estimates of State capital cost ,disabilities' from 1962,63 to 1995,96. Finally, we suggest how the methodology and the estimates of capital cost disabilities might be integrated into the Commission's formula to produce a grant distribution which reflects different costs of capital across States. [source]

Exciton Migration in Conjugated Dendrimers: A Joint Experimental and Theoretical Study

CHEMPHYSCHEM, Issue 18 2009
Muhammet E. Köse Prof.
Abstract We report a joint experimental and theoretical investigation of exciton diffusion in phenyl-cored thiophene dendrimers. Experimental exciton diffusion lengths of the dendrimers vary between 8 and 17 nm, increasing with the size of the dendrimer. A theoretical methodology is developed to estimate exciton diffusion lengths for conjugated small molecules in a simulated amorphous film. The theoretical approach exploits Fermi's Golden Rule to estimate the energy transfer rates for a large ensemble of bimolecular complexes in random relative orientations. Utilization of Poisson's equation in the evaluation of the Coulomb integral leads to very efficient calculation of excitonic couplings between the donor and the acceptor chromophores. Electronic coupling calculations with delocalized transition densities revealed efficient coupling pathways in the bulk of the material, but do not result in strong couplings between the chromophores which are calculated for more localized transition densities. The molecular structures of dendrimers seem to be playing a significant role in the magnitude of electronic coupling between chromophores. Simulated diffusion lengths correlate well with the experimental data. The chemical structure of the chromophore, the shape of the transition densities and the exciton lifetime are found to be the most important factors in determining the size of the exciton diffusion length in amorphous films of conjugated materials. [source]