The price relationship between organic and non-organic vegetables in the U.S.: evidence from Nielsen scanner data

This study investigates price relationships between organic and conventional carrots, tomatoes, and lettuce in the U.S. utilizing Nielsen scanner data from 2006–2015. We employ a threshold vector error correction model (TVECM), threshold vector autoregressive model (TVAR), and threshold cointegration test to test whether market integration exists between organic and conventional vegetables as well as the existence of asymmetric price transmission. The results find positive long-run relationships between organic and conventional prices of carrots and tomatoes and show the existence of asymmetric price transmission in price pairs of lettuce and tomatoes. Our findings suggest that the price relationship between organic and conventional vegetables varies by characteristics, such as shelf life, volatility in the price premium, and substitutability.     

The Practice Boundaries of Advanced Practice Nurses: An Economic and Legal Analysis

The purpose of this study is to examine the effects of State regulation that determines the extent of professional independence of advanced practice nurses (APNs). We find that in States where APNs have acquired a substantial amount of professional independence, the earnings of APNs are substantially lower, and those of physicians assistants (PAs) are substantially higher, than in other States. These results are striking since PAs are in direct competition with APNs; the only real operational difference between these groups is that PAs are salaried employees who must work under the supervision of a physician. The implication is that physicians have responded to an increase in professional independence of APNs by hiring fewer APNs and more PAs. The finding that earnings of APNs decline when they attain more professional autonomy vis-à-vis physicians reinforces work by Sass and Nichols on physical therapists.The content is the responsibility of the authors and does not represent official positions of the Federal Reserve Bank of St. Louis or the Federal Reserve SystemJEL classification: I11, I18, J31, J44, L51     

我国地区经济差异与城市化水平关系的实证分析

对改革开放以来地区经济发展水平的差异以及建国以来全国及各省区的城市化的发展进程进行了描述,利用格兰杰因果关系检验,研究我国不同经济发展阶段中城市化水平与经济增长的因果关系, 并采用国际上流行的Panel data方法从多个角度对城市化与地区经济增长的关系进行了分析研究。结论是:城市化水平的提高对于落后地区经济增长的促进作用要高于经济发达地区。     

Explaining Real Commercial Rents Using an Error Correction Model with Panel Data

This paper presents rent models for retail and office property in the United Kingdom. Panel data are used covering eleven regions for 29 years, enabling us to overcome the limitations of a relatively short time series. We use an error correction model (ECM) framework to estimate long-run equilibrium relationships and short-term dynamic corrections. The combination of panel data and an ECM is an innovative approach that is still being developed in economics. We construct new supply series that combine infrequent stock data with more frequent construction data. Separate regional models are estimated for retail and office properties. The regions are then combined into a number of panels on the basis of the income and price elasticities in the long-run and short-run models. Unlike previous studies, we find no evidence of a board north–south divide between low growth and high growth regions. Like these studies we do find a London effect: in London, demand elasticities for space with respect to both price (rent) and income are much lower in magnitude. We conclude that, while the economic drivers may vary, there is no evidence of differences in the operation of the regional property markets outside London. Elasticities for retail and office are similar. Our final models are parsimonious with single measures of economic activity and of supply and always support the use of an ECM.     

Estimating daily volatility in financial markets utilizing intraday data

This study proposes a new approach to the estimation of daily realised volatility in financial markets from intraday data. Initially, an examination of intraday returns on S&P 500 Index Futures reveals that returns can be characterised by heteroscedasticity and time-varying autocorrelation. After reviewing a number of daily realised volatility estimators cited in the literature, it is concluded that these estimators are based upon a number of restrictive assumptions in regard to the data generating process for intraday returns. We use a weak set of assumptions about the data generating process for intraday returns, including transaction returns, given in den Haan and Levin [den Haan, W.J., Levin, A., 1996. Inferences from parametric and non-parametric covariance matrix estimation procedures, Working paper, NBER, 195.], which allows for heteroscedasticity and time-varying autocorrelation in intraday returns. These assumptions allow the VARHAC estimator to be employed in the estimation of daily realised volatility. An empirical analysis of the VARHAC daily volatility estimator employing intraday transaction returns concludes that this estimator performs well in comparison to other estimators cited in the literature.     

A DEA Approach to Understanding the Productivity Growth of Malaysia's Manufacturing Industries

This paper seeks to explain the productivity growth performance of Malaysia's manufacturing sector using a panel data of 28 industries from 1981–1996. Here, the data envelopment analysis technique is used to calculate and decompose the Malmquist index of total factor productivity (TFP) growth into technical change, change in technical efficiency and change in scale efficiency. This allows the identification of the sources of productivity growth which is crucial for policy formulation. It was found that the annual TFP growth of the Malaysian manufacturing sector was low at 0.8% and this was driven by small gains in both technical change and technical efficiency, with industries operating close to optimum scale.     

基于Visual Basic6.0的测控软件设计

对VisualBasic6.0在测控系统软件编程方面的应用进行了探讨,并对其数据处理,I/O操作,动态链接库DLL的编制与调用,数据库管理系统的接口设计、建立、数据格式的转换等方面进行了研究。给出了Windows应用程序建立DLL的方法与步骤,对于在VisualBasic程序中如何应用DLL进行了讨论。     

The Global Determinants of Direct Office Real Estate Returns

We investigate the determinants of direct office real estate returns by analyzing rents, capital appraisals, and total returns. A recently compiled global database of major cities in Asia, Europe, and the United States provides a unique opportunity to give a macro-view on the effects of economic growth and supply and demand factors on nominal real estate returns. The global database provides quarterly observations from 1986 to 1999. To address the smoothness problem of appraisal-based price data and regulated rents, we employ the Generalized Method of Moments to estimate a dynamic panel-data model. The model allows us to combine the cross-sectional and time-series dimension in our quarterly data. We find that gross domestic product, inflation, unemployment, vacancy rate, and the available stock all have an effect on real estate returns.     

异步电机教学实验数据处理系统

本文介绍异步电机空载、短路、负载实验数据处理的数学方法和软件设计方法步骤,形成了实验教学软件。     

Real estate return correlations: Real-world limitations on relationships inferred from NCREIF data

Correlation estimates for returns between individual properties are subject to large inherent uncertainties due to limits on the amount of data that is likely to be available for the foreseeable future. After allowance for correlation sampling error, it is impossible to distinguish on an ex ante basis between the risk-reduction capabilities of mean-variance portfolio selection models and naive diversification without regard to property type or geographical location. The naive portfolio diversification strategies of typical institutional real estate portfolio managers are rational responses to limitations on the informational content of statistical analyses of historical real estate data.