An evaluation of the environmental care orientation of deciduous fruit producers in the Western Cape

A classification system developed to evaluate the environmental care orientation of companies and, more specifically, their strategies to deal with the environmental care requirements prescribed by the market was applied to the deciduous fruit sector in the Western Cape. A survey was done to determine the attitude towards and status of, environmental care activities amongst deciduous fruit producers who have already obtained Eurepgap certification or who are busy preparing for the certification audit. A questionnaire was used and the responses were judged in terms of the guidelines of the classification system. The nature of the typical South African - European deciduous fruit export supply chain is that South African producers desire to supply the retail market at higher prices than that of the wholesale market. The producers are then confronted with the stringent environmental care requirements of the retail chains, who use the environmental care product image aggressively as a selling point in the retail market, acting like typical Class III market oriented institutions. The classification shows that the majority of producers try to comply with these requirements with minimum effort (Class I). The more progressive producers accept them as good agricultural practices to increase their production efficiency. (Class II). Some farmers participate in a comprehensive Integrated Crop Management (ICM) system to establish a culture of environmental care at farm level in a more efficient way. ICM implementation also helps to prepare proactively for possible changes in the environmental care requirements of individual retail chains. This seems to be the more effective strategy for the primary producer.Crop Production/Industries, Environmental Economics and Policy,

Experimental and Theoretical Studies in Optical Coherence Theory

Visser, T.D. [Promotor]Ubachs, W.M.G. [Promotor

Bertrand Competition with an Asymmetric No-Discrimination Constraint

Abstract: We study the competitive and welfare consequences when only one firm must commit to uniform pricing while the competitor’s pricing policy is left unconstrained. The asymmetric no-discrimination constraint prohibits both behaviour-based price discrimination within the competitive segment and third-degree price discrimination across the monopolistic and competitive segments. We find that an asymmetric no-discrimination constraint only leads to higher profits for the unconstrained firm if the monopolistic segment is large enough. Therefore, a regulatory policy objective of encouraging entry is not served by an asymmetric no-discrimination constraint if the monopolistic segment is small. Only when the monopolistic segment is small and rivalry exists in the competitive segment does the asymmetric no-discrimination constraint enhance welfare.Dominant firms;price discrimination;competition policy;regulation

Price Discrimination Bans on Dominant Firms

Competition authorities and regulatory agencies sometimes impose pricing restrictions on firms with substantial market power — the “dominant” firms. We analyze the welfare effects of a ban on behaviour-based price discrimination in a two-period setting where the market displays a competitive and a sheltered segment. A ban on “higher-prices-to-shelteredconsumers” decreases prices in the sheltered segment, relaxes competition in the competitive segment, increases the rival’s profits, and may harm the dominant firm’s profits. We show that a ban on “higher-prices-to-sheltered-consumers” increases the dominant firm’s share of the first-period market. A ban on “lower-prices-to-rival’s-customers” decreases prices in the competitive segment, lowers the rival’s profits, and augments the consumer surplus. In particular, while second-period competition is relaxed by a ban on “lower-prices-to-rival’scustomers”, first-period competition is intensified substantially, which leads to lower prices “on-average” over the two periods. Our findings indicate that a dynamic two-period analysis may lead to conclusions opposite to those drawn from a static one-period analysis.dominant firms;price discrimination;competition policy;regulation

Structure and conductivity of pyrochlore and fluorite type solid solutions

High oxygen conductivities can be achieved in cation ordered LnxZrl-x=xO2-l/2x (Ln=Gd, Nd) solid solutions with pyrochlore (P) structure. High values of the pre-exponential factor σo are correlated with the degree of anion disorder in the 8b oxygen sublattice (neutron diffraction). The activation energy ΔH is lowered by cation ordering (F-P transition; effect of ) due to the occurence of a preferential diffusion path. Maximum oxygen conductivity is achieved in (1−x)Bi2O3−x Ln2O3 solid solutions with fluorite related δ-Bi2O3 structure for Ln=Er and x=0.20. Neutron diffraction measurements indicate the occurence of short range ordering in “Er-O units” with relative small interatomic distances at T < 820 K. This leads to an increased activation energy

Efficient estimation of income distribution parameters

The parameters of several families of distributions are estimated by means of minimum χ2; use is made of random samples taken from Dutch income-earning groups in 1973. The numerical search routine used, is the Complex method due to Box. The χ2 function is evaluated by standard numerical integration procedures. The lognormal and the Gamma families are rejected because of a poor fit. The log t and the log Pearson IV families are introduced. This results in a considerable improvement of χ2 critical levels. The generalized Gamma and the Champernowne function describe the income distribution reasonably well in some cases

Further experience in Bayesian analysis using Monte Carlo Integration

An earlier paper [Kloek and Van Dijk (1978)] is extended in three ways. First, Monte Carlo integration is performed in a nine-dimensional parameter space of Klein's model I [Klein (1950)]. Second, Monte Carlo is used as a tool for the elicitation of a uniform prior on a finite region by making use of several types of prior information. Third, special attention is given to procedures for the construction of importance functions which make use of nonlinear optimization methods. *1 This paper started as a revision of Van Dijk and Kloek (1978). In the course of the work our ideas developed to such an extent that the final result is an almost completely new paper. We are indebted to a referee for a number of very useful suggestions. We also wish to thank A.S. Louter and G. den Broeder of the Econometric Institute for their help in preparing the necessary computer programs

Bayesian estimates of equation system parameters, An application of integration by Monte Carlo

Monte Carlo (MC) is used to draw parameter values from a distribution defined on the structural parameter space of an equation system. Making use of the prior density, the likelihood, and Bayes' Theorem it is possible to estimate posterior moments of both structural and reduced form parameters. The MC method allows a rather liberal choice of prior distributions. The number of elementary operations to be preformed need not be an explosive function of the number of parameters involved. The method overcomes some existing difficulties of applying Bayesian methods to medium size models. The method is applied to a small scale macro model. The prior information used stems from considerations regarding short and long run behavior of the model and form extraneous observations on empirical long term ratios of economic variables. Likelihood contours for several parameter combinations are plotted, and some marginal posterior densities are assessed by MC