THE OPTIMAL CONCENTRATION OF CATTLE FEED SUPPLEMENTS

The paper deals with the optimal composition of cattle feed supplements which are prepared by feed mills and sold to cattle feeders. Two problems are distinguished. In the first problem the ratio in which supplement and main feed are utilised is considered as given, while in the second problem this ratio is optimally chosen.
The relationships between these two problems as well as their dual problems are analysed. It is indicated that feed mill profit margins for the supplement, based on the quantity of the supplement and the input costs, generally lead to supplements which are too concentrated. An application to a dairy ration is used as an example.
Cette étude s'occupe avec la composition optimale des suppléments fourragères préparés par des entreprises fourragères et vendus aux éleveurs de bétail. On distingue deux problèmes. Dans la première la proportion entre le supplément et le fourrage principal est prise pour donnée, et dans la seconde cette proportion est choisie optimalement.
Les relations entre les deux problèmes et les problèmes duales correspondantes sont analysées et on constate que des écarts bénéficiares des entreprises fourragères qui sont basés sur la quantité du supplément et les coûts des ingrédients en général out pour résultat des suppléments trop concentrés. Une application à une ration pour des vaches laitières est donnée pour exemple.     

Eliminating chain drift in price indexes based on scanner data

The use of scanner data in the CPI makes it possible to compile superlative price indexes at detailed aggregation levels since prices and quantities are available. A potential drawback is the high attrition rate of items. The usual solution to handle this problem, high-frequency chaining, can create drift in the index series due to price and quantity bouncing arising from sales. Ivancic, Diewert and Fox (2009) have recently proposed an approach that provides drift free, superlative-type indexes through adapting multilateral index number theory. In this paper we apply their proposal to seven product groups and find promising results. We compare the results with those obtained by using the Dutch method to deal with supermarket scanner data.     

Holt’s exponential smoothing and neural network models for forecasting interval-valued time series

Interval-valued time series are interval-valued data that are collected in a chronological sequence over time. This paper introduces three approaches to forecasting interval-valued time series. The first two approaches are based on multilayer perceptron (MLP) neural networks and Holt’s exponential smoothing methods, respectively. In Holt’s method for interval-valued time series, the smoothing parameters are estimated by using techniques for non-linear optimization problems with bound constraints. The third approach is based on a hybrid methodology that combines the MLP and Holt models. The practicality of the methods is demonstrated through simulation studies and applications using real interval-valued stock market time series.     

Model selection, estimation and forecasting in VAR models with short-run and long-run restrictions

We study the joint determination of the lag length, the dimension of the cointegrating space and the rank of the matrix of short-run parameters of a vector autoregressive (VAR) model using model selection criteria. We suggest a new two-step model selection procedure which is a hybrid of traditional criteria and criteria with data-dependant penalties and we prove its consistency. A Monte Carlo study explores the finite sample performance of this procedure and evaluates the forecasting accuracy of models selected by this procedure. Two empirical applications confirm the usefulness of the model selection procedure proposed here for forecasting.     

Global restrictions on the parameters of the CDES indirect utility function

This paper extends the analytical and empirical application of the basic indirect utility function of Houthakker–Hanoch—called the CDES specification (constant differences of elasticities of substitution). The non-homothetic CDES preferences are the natural parametric extension on the global domain of the homothetic CES preferences with many commodities, and CDES can conveniently be used in specifying CGE multisector models with a demand side satisfying observable Engel curve patterns. Moreover, all Marshallian own-price elasticities are no longer restricted to exceed one, and positive and negative cross-price effects are allowed for in empirical demand analyses. Explicit calculations of the Allen elasticities of substitution are instrumental in demonstrating the economic implications of the parameters of indirect utility functions with global regularity properties and flexibility of the derived demand systems.     

The Delphi method as early warning: Linking global societal trends to future radicalization and terrorism in The Netherlands

A Delphi study was performed to answer the question: Which global societal trends relate to future radicalization and subsequent terrorism in the Netherlands? An inventory of two hundred global societal trends and a literature study of radicalization together served as briefing of the participants in the Delphi study. The first two rounds were conducted in anonymous writing. The third round was a face to face focus group meeting. In the first and second round participants scored the trends, adjusted their scores relative to others and provided arguments, and in the focus group meeting, themes were discussed in which the participants remained to have strong opposite views. This approach emphasizes divergence in opinion (‘dissensus’), as opposed to convergence (‘consensus’). Consensus seeking to us seems to be the dominant application of Delphi, but we emphasize the value of seeking dissensus. We hypothesize that in those cases where the opposite views that were discussed kept their ground, this Delphi study may have found early warnings of future radicalization.The essence of this paper is that it is possible, with limited effort, to get a handle on the complex and poorly defined subject of global societal trends influencing future radicalization. Application of the Dissensus Delphi method provided a selection of early warnings that may be looked into with future research.     

Institutional capacity to dynamically innovate: An application to the Portuguese case

The present paper addresses the dynamics of innovation, by extending the analysis beyond a static-economic perspective. It offers a dynamic-institutional mapping of relational capacities to dynamically innovate. Its main goal is to contribute to the above-mentioned research theme by presenting a new methodology able to pinpoint different trends in the relational capacities of institutions when they are innovative. Thereby, major characteristics in the networks of innovation are identified. This investigation uses an extended set of private institutions and public organizations located in Portugal, evaluated by their WebPage contents. To this data set a new combination of multivariate statistical methods is applied to detect group performances, to compare them, and to identify gradients of capacity to dynamically innovate. The results demonstrate that this method can provide extremely useful and tailor-made information for policy evaluation at regional or national levels.     

Determinants of international fragmentation of production in European Union

The growth in world trade during the last decades was largely caused by increasing bilateral exchanges of parts and components as a consequence of international fragmentation of production. Apparently, the international integration of the Newly Industrializing and Eastern European economies prompted firms in ‘high-wage’ countries to exploit factor price differences in order to increase their international competitiveness. However, theory predicts that, beside factor price differences, international fragmentation of production should be driven by a multitude of additional determinants. Against this background, the present paper reveals empirical evidence on parts and components trade as an indicator for international fragmentation of production in the European Union and determines its main explanatory factors. The results of a panel data analysis show that especially industry specific factors as well as communication and transportation infrastructure are likewise important for shifting production to or sourcing components from foreign countries.     

A structural dynamic microsimulation model of household savings and labour supply

A structural model of the household is described that represents current best-practice in the analysis of savings and labour supply responses to the policy environment. Care has been taken in specifying the model so that it represents an appropriate basis for the analysis of incentive effects to policy change, and for exploring the empirical support for alternative structural assumptions. Matching the model to survey data for the UK reveals some interesting puzzles in relation to the timing of retirement.