AN ECONOMIC RESPONSE MODEL OF HERBICIDE APPLICATION FOR WEED CONTROL

A biologically realistic model of crop yield response to herbicide application is presented. It includes functions for weed mortality from herbicide application and yield loss due to surviving weeds. The optimal herbicide rate and two types of decision thresholds are derived theoretically and illustrated with empirical examples. Responses of the various decision criteria to changes in parameters are also examined theoretically and empirically. A multidimensional threshold for weeds based on weed density and weed-free yield is presented. The issue of farmers using other than officially recommended herbicide rates is discussed.     

Testing for non-linear dependence in inter-war exchange rates

Testing for Non-Linear Dependence in Inter-War Exchange Rates. — This paper tests weekly inter-war floating exchange rate data for the pound-dollar, pound-franc and pound-reichsmark for non-linearity. Initial tests reveal strong evidence of generic non-linearity in these series and indicate neglected non-linear structure in the residuals of linear representations. Attempts to model this structure using GARCH residual processes have only been partially successful. Thus, two parametric models of such non-linearity were estimated. Comparing the forecasts from these models shows the mean square forecast errors of linear-GARCH and bilinear models to be lower than those from linear forecasts for all series, and that SETAR model forecasts outperform all other models for the pound-dollar.     

Employment response to supply and demand shocks under envy in wage formation

Summary We analyse the impact of wage envy on employment and on its sectorial allocation. A multi-sector general equilibrium model in which externalities among sectors arise through wage envy and decentralized bargaining is presented. In the no externality case, sectorial employment is a function of sectorial productivity and of the disutility of work. In the externality case, sectorial employment is additionally affected by union power in all sectors (with a negative sign even though bargaining is efficient), by the productivity in the other sectors (with an undetermined sign) and by the relative average propensity to consume goods of this sector (with a positive sign).Rijksuniversiteit Limburg, FNRS and Université Catholique de Louvain. I would like to thank Franz Palm for valuable comments on an earlier draft. This paper benefitted also from discussions with Torben Andersen, Jacques Drèze and Henri Sneessens (without implying them in any mistake). The detailed comments of the anonymous referee contributed to a large extent to clarify the exposition of the model.     

Time series approaches to Italian regional convergence

This article investigates the evolution of the gap between Italian regions and Italy as a whole during the period of 1980 to 2007. We tested for the presence of the stochastic and β-convergence hypotheses using different time series approaches. The former was studied, first, for the entire sample period and then, with an exogenous instantaneous break in the series. The presence of β-convergence, instead, was estimated considering a known and an unknown trend break date model. Our results show that most of the regions do not converge in an ‘actual’ way, since they do not present a stochastic and β-convergence simultaneously.     

LONGER‐RUN EFFECTS OF ANTI‐POVERTY POLICIES ON DISADVANTAGED NEIGHBORHOODS

We assess evidence on the longer‐run effects of minimum wages, the Earned Income Tax Credit, and welfare on key economic indicators of economic self‐sufficiency in disadvantaged neighborhoods. The evidence suggests that the longer‐run effects of the Earned Income Tax Credit are to increase employment and to reduce poverty and public assistance. We also find some evidence consistent with higher welfare benefits having longer‐run adverse effects, and stronger evidence that tighter welfare time limits reduce poverty and public assistance in the longer‐run. The evidence on the longer‐run effects of the minimum wage on poverty and public assistance is not robust. (JEL J22, J23, J38)     

Public utility valuation and risk under incentive regulation

The objective of providing inducements for public utilities to seek to improve the efficiency of their operations has been a longstanding regulatory concern. Among the evolving strategies for furthering that objective is a shift toward what has come to be referred to as incentive regulation. We examine here how this departure from past regulatory practice will affect the market value and market risk of the utility firm, and the specific manner in which an incentive mechanism can be implemented in order to achieve a desired valuation outcome. A particular focus is the establishment of boundaries on allowed rates of return under incentive regulation which are consistent with that desired outcome. The likely impact on utility ratepayers is considered.     

Limits to creative destruction and technologies in practice: the case of ham radio

Drawing on the structurationist notion of ‘technologies-in-practice’, this article analyses the different types of technological actions that users perform, after technological change, in order to keep a declining technology alive over time. The research question of the article is: How do technologies-in-practice based on the application of new technology hamper the creative destruction of old technology? The case study of ham radio technology and amateur radio operators is explored. The results of the investigation support the development of a technology-in-practice ‘experimentation’ and four inductive research propositions.