威海地区年降水量的时间序列分析

通过应用时间序列分析技术,对威海地区1959-2002年降水量序列进行分析,证实年平均降水量序列满足ARIMA(1,1,(1,11))模型,并通过该模型对威海地区的2003-2007年降水量进行了预测分析。     

时间序列年的生态足迹计算——以甘肃省1990～2002年生态足迹的计算为例

运用恒定世界平均产量法对甘肃省1990～2002年的生态足迹进行了计算和分析;结果显示甘肃省的发展是通过消耗自然资本存量来弥补生态承载力的不足的,处于一种生态不协调状态;通过实证分析深入探讨了生态足迹方法存在的缺陷。     

A time series analysis of Danish markets for pork, chicken, and beef

We offer a first-time empirical depiction of Danish dynamic meat price/quantity transmissions by formulating, estimating, and testing a VAR model of market-clearing quantities and prices of the Danish pork, chicken, and beef markets. The analysis illuminates how these markets dynamically handle shocks, and it is demonstrated that: (i) the three meats are close substitutes; (ii) chicken and pork market shocks have own-market and cross-market effects that occur rapidly and swiftly, while beef market shocks have more enduring impacts on pork and chicken markets; (iii) prices are in general more endogenous than quantities; and (iv) the price of chicken is much more endogenous than the prices of pork and beef.     

Capturing zero‐trade values in gravity equations of trade: an analysis of protectionism in agro‐food sectors

With significant improvements in its theoretical underpinnings, the gravity model has gained renewed interest in the agro‐food trade literature. Notwithstanding, there is a dearth of literature examining the relative trade restrictiveness of tariff barriers across a broad range of agro‐food sectors. This represents an important research gap, which this study sets out to fill. Furthermore, this research reconciles the application of zero‐inflated models with a sectorally disaggregated analysis. More specifically, employing a fully specified gravity equation, a Poisson estimator and variants of the Poisson model (Negative Binomial, Zero‐Inflated Poisson, and Zero‐Inflated Negative Binomial) provide statistically significant and theoretically consistent estimates, while allowing for the inclusion of zero‐trade values. A panel data model with fixed effects is also employed to improve the estimation of the parameters of interest. Estimation results reveal that in the vast majority of sectors examined, import tariffs are found to be statistically significant, whereas export refunds exhibit a statistically smaller role due to the nonsystematic nature of their application in world food markets. Model simulations of tariff barrier eliminations reveal limited trade gains, although there is encouraging evidence of “low” and “lower middle” per capita income country trade gains in wheat, red meat, dairy, sugar, and (particularly) rice markets.     

A discrete‐time hazard analysis of the exit of burley tobacco growers in Tennessee,North Carolina,and Virginia

This article examines the exit and survival dynamics of burley tobacco growers in Tennessee, North Carolina, and Virginia using a discrete‐time hazard logit model. The study also predicts the effects of selected farm and family characteristics on exit hazards, assesses the proportionality of their effects over time and their relative importance in explaining the variation in exit hazards among burley tobacco growers. Results provide the longitudinal progression of the probability of exiting the tobacco industry since the end of the federal tobacco program in 2004, and identify off‐farm participation, percentage of farm receipts from tobacco, tobacco price, educational level, and farm size as the most important determinants of the decision to exit the tobacco industry. Further, the effects of off‐farm participation and farm size on the exit hazards of burley tobacco farms are proportional over time while the effects of the percentage of farm receipts from tobacco and tobacco price are time variant.