Relative convergence and unbalanced growth

This paper introduces a general, formal treatment of dynamic constraints, i.e., constraints on the state changes that are allowed in a given state space. Such dynamic constraints can be seen as representations of "real world" constraints in a managerial context. The notions of transition, reversible and irreversible transition, and transition relation will be introduced. The link with Kripke models (for modal logics) is also made explicit. Several (subtle) examples of dynamic constraints will be given. Some important classes of dynamic constraints in a database context will be identified, e.g. various forms of cumulativity, non-decreasing values, constraints on initial and final values, life cycles, changing life cycles, and transition and constant dependencies. Several properties of these dependencies will be treated. For instance, it turns out that functional dependencies can be considered as "degenerated" transition dependencies. Also, the distinction between primary keys and alternate keys is reexamined, from a dynamic point of view.

Threshold effects of energy price changes

This paper presents a theoretical model emphasising energy investments’characteristics of uncertainty and irreversibility. The theoretical modelsuggests threshold effects. Firms are induced to substitute away from energyonly if prices of energy exceed a certain threshold level and they reverse thetechnology only if energy prices are low enough. Estimating a simpleinvestment relation using panel data for the Dutch economy, we findevidence for threshold effects.

The Human Side of Diabetes Care

Theory predicts that the presence of fixed costs affects the relationship between energy use and energy price changes, as the firm's output and investment decisions respond differently to energy price increases and decreases. The asymmetry in response to energy price changes is exacerbated by uncertainty with respect to future energy prices, but to date the empirical literature does not explicitly take uncertainty into account. The contribution of this paper is twofold. First, we develop a new measure of energy price uncertainty. Second, we apply the measure to explain energy use in 8 OECD countries between 1978 and 1996, trying to identify whether indeed energy price uncertainty effects the asymmetry resulting from changes in energy use.