两端铰支二跨梁的临界压力分析

推导出了两端铰支二跨梁的临界压力表达式，具体导出了两跨长度相等情况下的临界压力计算公式，此公式与等长度的单跨梁的欧拉临界压力公式的形式完全相同。     

The impact of environmental regulation on productivity in German industries

The objective of this paper is to adjust a traditional total factor productivity (TFP) measure for the direct effect of environmental regulation on material and capital input. For this purpose we consider the fact that part of material input and pollution abatement capital have not been used to increase output but to cover the cost of using the environment as a factor of production. Therefore TFP growth rates are lower if part of the material input is allocated to abatement activities instead of producing output. We propose to treat compliance with environmental regulation as an unproductive input linked to the use of productive material input. Our aim is to answer and discuss two questions: How to measure the effect of environmental regulation on TFP, and does the effect matter. We examine data from 1975–1991 for ten pollution intensive German industries.We would like to thank Cornelia Oßwald for valuable research assistance. We are especially grateful to two anonymous referees for many helpful comments.     

Pricing-to-market tests in instrumental regressions: Case of the transportation equipment industry

Pricing-to-market (PTM) theory suggests that exporting monopolistic firms adjust their destination-specific mark-ups in the face of exchange rate shocks. A large proportion of the existing evidence for PTM comes from Wald tests applied to OLS- and IV-estimated parameters of single-equation models. Such tests can seriously over-reject in the presence of endogeneity and weak instruments so that some of the available results supporting PTM could be spurious. In this paper we revisit the PTM evidence for Japanese and German exporting firms in the transportation equipment industry. Using the model of Marston (1990), we apply exogeneity and LR-LIML-based tests for which the error probability is controlled irrespective of the quality of the available instruments. Our results show right-hand-side endogeneity in almost all of the examined PTM equations. In addition, we find that statistical decisions often differ depending on whether they are based on the traditional Wald test or on our proposed test.The authors would like to thank Philippe Barla, Jean-Thomas Bernard, Christos Constantatos, Larry Schembri, seminar participants at the Bank of Canada, and two anonymous referees for useful comments and suggestions. Thanks also to Richard Marston for providing data. Finally, a special thanks to Marjorie Santos for excellent research assistance. All remaining errors are our own and should not be attributed to the Bank of Canada.First version received: May 2002/Final version received: December 2002     

Productivity,earnings, and profit sharing — An econometric analysis of alternative models

The theoretical status of the relationship between productivity, wages, and profit sharing (PS) is poor. Only some alternative hypotheses can be formulated. From these explanations six different econometric models are derived. Using data of the German Socio-Economic Panel the models are estimated and tests and indicators are employed to choose the best model. Our investigation speaks in favour of hybrid simultaneous Tobit models where the level of profit sharing is positively correlated with productivity which induces positive wage effects on the one hand. But on the other hand the level of wages is also relevant to the question whether a firm introduces or decides to continuePS and which amount ofPS should be paid.What is obvious is not always true and introspection is a notoriously unreliable guide to empirical magnitudes. Blinder (1990, p.2)     

Expected utility theory and the experiments

The experimental evidence against expected utility theo or unconvincing. When one modifies the experiments to mi tends to support traditional theory.Dewey H. Johnson Professor of Economics, Department of Economics, College of Business Administration, University of South Carolina. I am grateful for comments from seminar participants at the University of Melbourne, University of South Carolina, University of Stockholm, and the University of Western Ontario. John Hey provided a firm, but sympathetic, editorial hand.     

Stationary solution to the overlapping generations model of fiat money: Experimental evidence

Overlapping generations model of fiat money yields an infinity of competitive equilibrium solutions, only one of which is stationary. Economies reported in this paper involved a sequence of overlapping generations of three or four individuals; each individual lived for two periods. In their young age individuals were endowed with chips that could be traded for fiat money wish the individuals of the old generation. In their old age, individuals could exchange their units o flat money for the consumption good. Results of the experiments exhibit some support for the stationary solution. The results are robust to two designs of exchange institutions (double oral auctior and supply schedule auction) and to two different endogenous ways of converting money into chips at the end of the game (average price prevailing during the last period the game is actually played and the average price forecast made during the last period the game is actually played).A preliminary version of this paper was presented at the meeting of the Economic Science Association and at the Federal Reserve Bank of Minneapolis. The authors are grateful for comments received from various participants at both presentations. Financial support was provided by the McKnight Foundation, the Honeywell Foundation, National Science Foundation (SES 89-12552), and Richard. M. and Margaret Cyert Family Funds.     

Price determination and dynamic adjustments: An inverse demand system approach to meat products in the United States

In this study the process of retail meat price determination is depicted in the form of an inverse demand system taking into consideration the dynamic adjustments present in monthly consumption data. The general dynamic framework identifies both long run and short run effects in a systematic manner and allows direct estimation of the long run price and scale flexibilities that are consistent with theory. The empirical application based on monthly U.S. meat products data provides reasonable and promising results.The authors are senior econometrician, Department of Risk Management, TRS, American Express Co., Phoenix, and assistant professor, Department of Applied Economics, University of Minnesota, St. Paul, respectively. The work was performed when the first author was an assistant research scientist at the Center for Agricultural and Rural Development, Department of Economics, Iowa State University, Ames. Journal Paper No. J-15784 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 3109.     

Stock prices,production and interest rates: Comparison of three European countries with the USA

This paper investigates the relationships between stock returns, changes in production, and changes in interest rates in three European countries: France, Germany, and the United Kingdom. The results obtained using annual data are much more conclusive than those obtained using quarterly data. Stock returns are affected by current changes in interest rates and by future changes in production. The dependence on changes in interest rates seems to be higher than on changes in production. Furthermore, the influence of future changes in production on stock returns diminishes substantially when contemporaneous changes in interest rates are taken into account. With reference to these points, the European markets behave in a similar fashion, but are in sharp contrast with the U.S. market.I am very grateful to Kay Davidson, Patric Hendershott and two anonymous referees for useful comments and suggestions. I am solely responsible for all remaining errors.     

Persistence,mean reversion and non-linearities in the US housing prices over 1830–2013

The objective of this study is to provide a direct estimate of the degree of persistence of measures of nominal and real house prices for the US economy, covering the longest possible annual sample of data, namely 1830–2013. The estimation of the degree of persistence accommodates for non-linear (deterministic) trends using Chebyshev polynomials in time. In general, the results show a high degree of persistence in the series along with a component of non-linear behaviour. In general, if we assume uncorrelated errors, non-linearities are observed in both nominal and real prices, but this hypothesis is rejected in favour of linear models for the log-transformation of the data. However, if autocorrelated errors are permitted, non-linearities are observed in all cases, and mean reversion is found in the case of logged prices, though given the wide confidence intervals, the unit root null hypothesis cannot be rejected in these cases.