Empirical Bayes analysis of log-linear models for a generalized finite stationary Markov chain

This article presents the empirical Bayes method for estimation of the transition probabilities of a generalized finite stationary Markov chain whose ith state is a multi-way contingency table. We use a log-linear model to describe the relationship between factors in each state. The prior knowledge about the main effects and interactions will be described by a conjugate prior. Following the Bayesian paradigm, the Bayes and empirical Bayes estimators relative to various loss functions are obtained. These procedures are illustrated by a real example. Finally, asymptotic normality of the empirical Bayes estimators are established.     

Simpler Probabilistic Population Forecasts: Making Scenarios Work

The traditional high-low-medium scenario approach to quantifying uncertainty in population forecasts has been criticized as lacking probabilistic meaning and consistency. This paper shows, under certain assumptions, how appropriately calibrated scenarios can be used to approximate the uncertainty intervals on future population size and age structure obtained with fully stochastic forecasts. As many forecasting organizations already produce scenarios and because dealing with them is familiar territory, the methods presented here offer an attractive intermediate position between probabilistically inconsistent scenario analysis and fully stochastic forecasts.     

Causality: a Statistical View

Statistical aspects of causality are reviewed in simple form and the impact of recent work discussed. Three distinct notions of causality are set out and implications for densities and for linear dependencies explained. The importance of appreciating the possibility of effect modifiers is stressed, be they intermediate variables, background variables or unobserved confounders. In many contexts the issue of unobserved confounders is salient. The difficulties of interpretation when there are joint effects are discussed and possible modifications of analysis explained. The dangers of uncritical conditioning and marginalization over intermediate response variables are set out and some of the problems of generalizing conclusions to populations and individuals explained. In general terms the importance of search for possibly causal variables is stressed but the need for caution is emphasized.     

Resourceful Sensemaking in an Administrative Group

ABSTRACT In this study, we present the concept of resourceful sensemaking as an extension of Weick's sensemaking theory. Resourceful sensemaking extends Weick's theory by carefully examining the influence of the lifeworld on organizational sensemaking practices. Lifeworld factors that affect organizational sensemaking are brought out in a dialectical method wherein a working definition of the resourceful sensemaking concept is compared with the sensemaking practices of an administrative group. We then show how this dialectical method can help develop a more robust formulation of the resourceful sensemaking concept. The paper ends by discussing the strengths and shortcomings of the concept and suggesting directions for future organizational sensemaking research.     

Increasing cooperation among plants,symbionts, and farmers is key to past and future progress in agriculture

The collective welfare of crop plants, their microbial symbionts, farmers, and society can be undermined by tragedies of the commons. A crop could increase resource allocation to grain if each plant invested less in sending roots into soil already explored by neighbors and less in stem growth. But evolutionary fitness depends on which plants capture the most soil resources and light (e.g., by growing taller than their neighbors), not just on the efficiency with which those resources are used. As for symbionts, with several strains infecting each plant, only host-imposed sanctions limit the fitness of strains that divert more resources to their own reproduction, at the expense of activities that benefit their host plant. Similarly, individual farmers do not necessarily benefit from pest- and resource-management practices that benefit farmers collectively or society as a whole. Plant breeders have increased crop yields by reversing past selection for individual fitness and they could breed for crops that would favor more-cooperative microbial symbionts. Better aligning interests among farmers and society may be more difficult.     

The empire strikes back: Adam Smith,John Stuart Mill,and the Robust Political Economy of empire

Recent scholarship regarding the idea of a U.S. Empire has raised serious questions as to the feasibility and desirability of imperial ambitions. This paper traces the debate over the net-benefit of empire back to the Classical economists. Adam Smith argued that the British Empire was a net cost while John Stuart Mill concluded the same empire was a net benefit. Contemporary arguments about a U.S. Empire map neatly to the divergent views of Smith and Mill. In addition to engaging in an exercise in history of thought, we use Smith’s political economy as a means of adjudicating between the different claims regarding the feasibility of empire. In doing so, we subject the claims of proponents of American Empire against the standard of robust political economy, which holds that intervention must generate desirable outcomes where less than ideal incentive and epistemic conditions hold. In doing so, we conclude that many of the claims made by proponents are fragile under less than ideal conditions.     

Review of Microstructural Evidence of Magmatic and Solid-State Flow

Evidence of magmatic flow includes: (a) parallel to sub-parallel alignment of elongate euhedral crystals (e.g., of feldspar or hornblende) that are not internally deformed, (b) imbrication (‘tiling’) of elongate euhedral crystals that are not internally deformed, (c) insufficient solid-state strain in regions between aligned or imbricated crystals to accommodate phenocryst rotation, (d) elongation of microgranitoid enclaves without plastic deformation of the minerals, (e) magmatic flow foliations and elongate microgranitoid enclaves deflected around xenoliths, and (f) schlieren layering (if due to flow sorting) in the absence of plastic deformation of the minerals involved. These features are consistent with rotation of crystals in a much weaker medium, namely a melt phase, at a stage when the magma has become viscous enough to preserve the alignment. Evidence of solid-state flow includes: (a) internal deformation and recrystallization of grains, (b) recrystallized “tails,” (c) elongation of recrystallized aggregates (e.g. of quartz and mica), (d) grainsize reduction, (e) fine-grained folia anastomosing around less deformed relics, (f) microcline twinning, (g) myrmekite, (h) flame perthite, (i) boudinage of strong minerals, typically with recrystallized aggregates of weaker minerals (e.g. quartz and mica) between the boudins, (j) foliation passing through, rather than around enclaves, and (k) heterogeneous strain with local mylonitic zones. Several criteria suggest “submagmatic flow,” including recrystallized feldspar, inferred transitions from magmatic imbrication to solid-state S/C arrangements, evidence of c-slip in quartz, and especially evidence of migration of residual melt into lower-pressure sites. Recent experimental studies indicate that a change from grain-supported flow to suspension flow typically occurs in deforming magmas at melt contents of between 20% to 40%, and that large amounts of strain may accumulate in magmas without being recorded by the final fabric. At lower melt percentages, perhaps as low as a few percent, depending on the minerals and their shapes, strain may be accommodated by: (a) melt-assisted grain-boundary sliding, (b) contact-melting assisted grain-boundary migration, (c) strain partitioning into melt-rich zones, (d) intracrystalline plastic deformation (c-slip in quartz indicating plastic deformation at temperatures near the granite solidus), and (f) transfer of melt to sites of low mean stress. The only indication of strain in the absence of crystal plasticity may be an alignment of crystals. Moreover, magmatic flow microstructures may be destroyed by fracturing, crystal plasticity and recrystallization before the magma reaches its solidus. Many rocks show evidence of solid-state flow superimposed on magmatic flow. Evidence of magmatic flow is commonly preserved in deformed felsic metamorphic rocks: for example the alignment of rectangular K-feldspar megacrysts and of microgranitoid enclaves. However, absence of alignment does not preclude a magmatic origin for K-feldspar megacrysts in felsic gneisses, as magmatic flow may cease before the magma becomes viscous enough to preserve an alignment.     

The Fossil Production Function in a Vintage Model

This paper extends the fossil production function to incorporate embodied technical change. The fossil production function provides an alternative to the standard neoclassical explanation for the aggregate production function. In a Classical Ricardian spirit, the paper assumes that capital-using, labour saving technical change prevails, and shows that it generates a fossil production function in Cobb-Douglas form. The power term of the production function mediates the viability of new machines. A sufficient condition for viability is that the power term equals or exceeds the profit share on new machines. Empirical estimates show that this sufficient condition is satisfied, a result inconsistent with the neoclassical interpretation of the aggregate production function.     

E–Commerce and the Australian Economy

This paper considers the likely impact of e–commerce and the Internet on the Australian economy. It surveys literature on the extent and development of e–commerce in Australia and its impact on the shape of the Australian economy. Evidence for the 'renewal' of the Australian economy is presented and examined, especially the question of whether Australia has enjoyed increases in productivity as a result of the production and/or use of new information and communications technology. Australia is seen as broadly well placed to benefit from the Internet and e–commerce. Traditionally isolated from the world's main economic centres and reliant on commodities in international trade, the advent of the Internet is ideal for a country in transition to a service–orientated, knowledge–based economy. As the composition of Australia's exports becomes more service–orientated and knowledge–intensive, traditional trading links with Europe and North America may strengthen relative to those with Asia.