Variety of Methodological Approach in Economics

It has been argued by some that the distinction between orthodox economics and heterodox economics does not fit the growing variety in economic theory, unified by a common methodological approach. On the other hand, it remains a central characteristic of heterodox economics that it does not share this methodological approach, but rather represents a range of alternative methodological approaches. The paper explores the evidence, and arguments, for variety in economics at different levels, and a range of issues which arise. This requires in turn a discussion of the meaning of variety in economics at the different levels of reality, methodology, method and theory. It is concluded that there is scope for more, rather than less, variety in economic methodologies, as well as within methodologies. Further, if variety is not to take the form of “anything goes”, then critical discussion by economists of different approaches to economics, and of variety itself, is required

Computer simulation of the effect of coherency strain on cluster growth kinetics

To understand clustering behavior under the influence of a coherency strain, Monte Carlo simulations were carried out for both two-dimensional (2-D) square and three-dimensional (3-D) simple cubic lattices. In the Monte Carlo model, each solute was assumed to exert coherency stress owing to a tetragonal misfit strain and to have surface energy when in contact with solvent atoms. To account for the coherency strain of a cluster whose morphology continuously changes during aging, exact expressions for both the self-strain energy and elastic interaction term for rectangular parallelepipeds were derived. Strong elastic interactions among platelike clusters are shown to develop a stabilized structure with a tendency for bridging the clusters at a right angle. In the early stage of evolution, solute atoms were found to diffuse into regions of stress concentration. Morphological changes revealed step movements on the edge of a cluster, and some steps were moving in the direction of dissolution (rather than growth) for the cluster, thus displaying a dynamic nature of step movement. When an initial shape was an elastically unstable one, a large cluster was found to dissolve into its solid solution, while, in the same environment, a cluster of the same size with a stable morphology sustained growth. During dynamic evolution, some clusters showed concave, instead of convex, surfaces, even though the former are highly nonequilibrium shapes. © 1991 The Minerals, Metals and Materials Society, and ASM International

Pedigree and mating system analyses in a western larch (Larix occidentalis Nutt.) experimental population

$\bullet$The mating pattern and gene flow in a western larch (Larix occidentalis Nutt.) experimental population was studied with the aid of microsatellite markers and a combination of paternity-mating system analysis. The commonly difficult to assess, male gametic contribution was determined with 95% confidence and its impact on genetic gain and diversity was determined. $\bullet$ Male fertility success rate ranged between 0 and 11%. Male reproductive output parental imbalance was observed with 50% of the pollen being produced by the top 5% of males while the lower 39% males only produced 10% of the pollen. $\bullet$ A significant difference was observed between male effective population size (genetic diversity) estimates from paternity assignment compared to those based on population's census number (21 vs. 41); however, this difference did not affect estimates of genetic gain. $\bullet$ A total of 221 full-fib families were identified (sample size range: 1–8) and were nested among the studied 14 seed-donors. $\bullet$ A combination of paternity-mating system analysis is recommended to provide a better insight into seed orchards' mating dynamics. While pollen flow tends to inflate mating system's outcrossing rate, the paternity analysis effectively determined the rate and magnitude of contamination across receptive females.Analyse de paternité et du mode de croisement dans une population expérimentale de mélèze occidental (Larix occidentalis Nutt.). $\bullet$ Les modes de croisement et les flux de gènes dans une population expérimentale de mélèze occidental (Larix occidentalis Nutt.) ont été étudiés à l'aide de marqueurs microsatellites et d'une analyse combinée de paternité et du système de reproduction. La contribution gamétique mâle – communément difficile à estimer – a été déterminée avec un seuil de confiance de 95 % et son impact sur le gain génétique et la diversité a été déterminé. $\bullet$ Le taux de succès reproductif mâle était compris entre 0 et 11 %. Un déséquilibre dans la contribution des parents mâles a été observé avec la production de 50 % du pollen par 5 % des pères alors que 39 % d'entre eux ne contribuaient que pour seulement 10 % du pollen. $\bullet$ Une différence significative a été observée entre la taille efficace de la population mâle (diversité génétique) estimée par la recherche de paternité et celle basée sur les effectifs recensés de la population (21 vs. 41) ; cependant, cette différence n'affecte pas l'estimation du gain génétique. $\bullet$ 221 familles de plein-frères ont été identifiées (effectifs entre 1 et 8), regroupées parmi les 14 arbres-mères étudiés. $\bullet$ La combinaison d'une analyse de paternité et du système de reproduction est recommandée pour étudier de manière approfondie la dynamique de croisement en vergers à graines. Tandis que les flux de pollen tendent à augmenter le taux d'inter-croisements, l'analyse de paternité détermine de manière effective le taux et l'amplitude de contamination des arbres-mères