RESPONSES TO RISK IN WEED CONTROL DECISIONS UNDER EXPECTED PROFIT MAXIMISATION

Risk is an important characteristic of decisions about weed control in crops. In this paper it is shown that risk can affect weed control decisions even if the objective of the decision maker is to maximise expected profits: that is, even if the decision maker is ‘risk-neutral’ in the usual economic sense. This is shown for two decision frameworks: the optimal rate approach and the economic threshold approach. Empirical results are presented for control of ryegrass in wheat in Western Australia. It is found that, in general, risk reduces the optimal level of herbicide use under expected profit maximisation. Although individual sources of risk have a small impact on the optimal decision rules, combinations of uncertain variables can have a relatively large effect.     

AGRICULTURAL RESEARCH EXPENDITURES AND AGRICULTURAL PRODUCTIVITY CHANGE

This note comments on the econometric analysis of the dynamic relationship between agricultural research expenditures and agricultural productivity change. The validity of the Almon restrictions, particularly endpoint restrictions, commonly imposed on the distributed lag is questioned. It is suggested that models incorporating such restrictions may lead to biased estimates of the effects of research spending. More fundamentally, doubts are raised as to whether any meaningful relationship between research spending and productivity change can be established from the available data.     

Stock market efficiency the evidence from FTA indices of eleven major stock markets

Summary This article presents a survey of recent literature on stock market efficiency, with special reference to the US and Dutch stock markets. Additionally, models are specified and estimated for the daily return since 1987 on FTA indices for eleven major stock markets, allowing for non-normality, heteroskedasticity, leverage effects and autocorrelation. The leverage effect and positive autocorrelation are characteristics of some of the indices investigated. The magnitude of the autocorrelation, however, is so small, that no profitable arbitrage opportunities arise and weak-form efficiency of these stock markets is not rejected.     

Structural changes in U.S. agriculture: Implications for African American farmers

Structural changes in U.S. agriculture, influenced by technological and institutional forces, have altered the economic and social characteristics of rural America, especially that segment of rural America populated by farmers and their families. Changes in the structure of agriculture have greater implications for small scale farmers, many of whom are African American, in that strategic options for their farm-firms are constrained to: increasing their farm size, exiting farming, and obtaining off-farm employment to survive. This article presents a rationale for public support of limited resource farmers, identifies structural trends in U.S. agriculture and their impacts on African American farmers, discusses economic problems unique to these farmers, and recommends needs for specific public policies and development programs.     

Savings,pension rights and taxation

Summary The voluntary saving rate has declined in The Netherlands over the last thirty years. In this paper the increasing share of transfer income in total income, with a high propensity to consume, and the increase in collective pension schemes are simultaneously used to explain this development. Furthermore, the influence of taxes is modelled. The planning horizon of the representative consumer is treated as a parameter to be estimated. The planning horizon obtained (about 4.5 years) appears to be short compared to expected residual lifetime, implying rather small interest elasticities. The estimation results indicate that, in case the obligatory pension schemes are diminished, the representative consumer offsets the loss in pension benefits for 75 per cent by voluntary, additional accumulation of nonhuman wealth in the long run. The working of the model is illustrated by simulation experiments.I wish to thank two anonymous referees, Prof. J. Pen, G.M.M. Gelauff, J.J. Graafland, W. Vossers and other colleagues of the CPB for their helpful comments.     

Using dead reckoning in economic projections

Economics is an inexact science, measurement of basic data is at best approximate, and most interesting relationships change relatively rapidly in developing countries. Key variables determining economic prospects are often impossible to include into models. Models and their mathematical algorithms however are deceptively precise, which often complicates the process of constructing and using economic projection models in developing countries.This paper will examine those macro models intended for operational policy purposes and how they are used. These models try to be analytically good and have sufficient plausibility to influence policy. Thus, a great deal of judgment is required in constructing, using, and interpreting projection models in developing countries: the “dead reckoning” element.     

广东老字号品牌文化内涵及形成机制研究

本文从文化解释的角度对广东老字号品牌文化的内涵进行研究。通过对24家知名度高、代表性强的广东老字号的相关品牌信息做内容分析,总结出10个代表广东老字号品牌文化内涵的词语,然后对它们进行了归类和分层,接着提练出广东老字号品牌精神的词语——神秘、永恒和可信。在此基础上结合“天地人”品牌营销模型进行了解释,最后从儒家文化、超自然崇拜和岭南文化的影响三方面对广东老字号品牌文化内涵的形成原因进行了解释。     

当前我国货币政策的两难选择及政策建议

通过对1990-2009年的中国经济数据进行实证分析,考察了货币政策对通货膨胀的影响.针对实证分析的结果及目前我国经济实际运行的状况,本文认为货币当局在维持宽松货币政策的同时,应该主要依靠公开市场手段,防止流动性泛滥;应密切关注资产价格,侧重引导市场预期;进行窗口指导,调整产业结构;维持汇率稳定,增强产品出口竞争力.     

Global and regional inequality in the distribution of income: Estimation with limited and incomplete data

The paper examines the nature and extent of global and regional inequality using the most recent country level data on inequality drawn from World Bank studies, and real per capita income from the Penn World Tables, for the period 1980–1990. The methodology employed in the paper is based on a mixture of parametric and non-parametric approaches to inequality measurement. It is designed to handle the limited and incomplete nature of income distribution data from different countries. Empirical results show a very high degree of global inequality, but with some evidence of catch-up and convergence between regions.