A censored system of cigarette and alcohol consumption

Many previous studies of US cigarette and alcohol consumption have focused on single equations. However, the addictive nature of consumption suggests that it is more appropriate to model these products as a system. We propose a two-step estimation procedure and apply the procedure to a system of equations for cigarette, beer and wine consumption. Results differ from those derived from an existing two-step procedure. Findings suggest that consumption of cigarettes, beer and wine is responsive to income changes but the elasticities are rather small. Personal physiques, education, age, race, ethnicity, health, gender, employment status, and regions also play significant roles in consumption.     

Household demand for fats and oils: two-step estimation of a censored demand system

A censored system of household fat and oil demand equations is estimated with a two-step procedure, using cross-sectional data from the 1987–1988 US Nationwide Food Consumption Survey. Own price and total expenditure elasticities are close to unity and there is no evidence of gross substitutability. Compensated elasticities suggest net substitution among the products considered.     

Does PPP hold in African countries? Further evidence based on a highly dynamic non-linear (logistic) unit root test

With a view to investigating whether the purchasing power parity (PPP) theory holds true for selected African countries during the January 1980–December 2003 period, we employ a rigorous, highly dynamic non-linear (logistic) unit root test, as first advanced by Leybourne et al. (1998 Leybourne, S, Newbold, P and Vougas, D. 1998. Unit roots and smooth transitions. Journal of Time Series Analysis, 19: 83–97. [Crossref] , [Google Scholar]), which is considerably more powerful than those tests traditionally used. Compared with the rejection of the null of the unit root process for only one of the 22 countries under study when we use the traditional ADF, PP, KPSS, NP and the DF-GLS unit root tests, with the Leybourne et al. (1998 Leybourne, S, Newbold, P and Vougas, D. 1998. Unit roots and smooth transitions. Journal of Time Series Analysis, 19: 83–97. [Crossref] , [Google Scholar]) test, we strongly reject the null of the unit root process for a surprising six of the 22 countries. These empirical results clearly indicate that PPP holds true for these six countries, namely the Central African Republic, the Côte d’Ivoire, Kenya, Madagascar, Uganda and Lesotho.     

Towards solving the PPP puzzle: evidence from 113 countries

Several different approaches have been followed by researchers to test the validity of Purchasing Power Parity (PPP). Since the introduction of the unit-root tests, researchers have applied a battery of these tests to determine whether the real exchange rates are stationary. If the answer is in the affirmative, PPP is validated. While application of the standard augmented Dickey–Fuller test has not provided much support for PPP, a test that incorporates nonlinearity in the rates has. Under both tests, however, the null of nonstationary is tested against the alternative of stationarity. In this article, when we switch the null with the alternative and apply Kwiatkowski et al. (1992 Kwiatkowski, D, Phillips, PCB, Schmidt, P and Shin, Y. 1992. Testing the null hypothesis of stationarity against the alternative of a unit root. Journal of Econometrics, 54: 159–78. [Crossref], [Web of Science ®] , [Google Scholar]) test, we provide relatively more support for the theory, getting closer and closer towards solving the PPP puzzle.     

Trade and transport connectivity: a spatial approach

This article aims to analyse whether transport connectivity affects trade flows using a spatial approach. We consider first-order contiguity and incorporate logistics network structure dependence in a spatial autoregressive model. The results provide evidence regarding the role of the location of logistics platforms for satisfying existing demand for transport structure in Spain.     

Crypto-currency bubbles: an application of the Phillips–Shi–Yu (2013) methodology on Mt. Gox bitcoin prices

The creation of bitcoin heralded the arrival of digital or crypto-currency and has been regarded as a phenomenon. Since its introduction, it has experienced a meteoric rise in price and rapid growth accompanied by huge volatility swings, and also attracted plenty of controversies which even involved law enforcement agencies. Hence, claims abound that bitcoin has been characterized by bubbles ready to burst any time (e.g. the recent collapse of bitcoin’s biggest exchange, Mt Gox). This has earned plenty of coverage in the media but surprisingly not in the academic literature. We therefore fill this knowledge gap. We conduct an econometric investigation of the existence of bubbles in the bitcoin market based on a recently developed technique that is robust in detecting bubbles – that of Phillips et al. (2013a). Over the period 2010–2014, we detected a number of short-lived bubbles; most importantly, we found three huge bubbles in the latter part of the period 2011–2013 lasting from 66 to 106 days, with the last and biggest one being the one that ‘broke the camel’s back’ – the demise of the Mt Gox exchange.     

东道国制度对企业海外并购行为的影响

在现有研究的基础上,将制度理论纳入企业海外并购研究。以中国上市公司实施的216起海外并购案例为数据基础,对东道国制度的5个维度(政治、经济、文化、管制和法律)与中国企业海外并购行为倾向的相关性进行回归分析。得出结论:政府管制、经济自由度、政治制度和文化差异等是影响企业海外并购行为的重要因素。     

长江经济带农业用水绿色效率测度及影响因素分析——基于超效率EBM-Geodetector模型

目的 农业用水的可持续利用关系到区域农业绿色发展及社会经济高质量发展。方法 文章基于2010—2018年长江经济带11省市的面板数据,运用超效率EBM模型对长江经济带农业用水经济效率、环境效率及绿色效率进行测度,并借助核密度估计及ArcGIS空间分析等方法分析其时空演变规律,最后利用地理探测器模型探究其影响因素。结果 （1）2010—2018年长江经济带11省市农业用水经济效率、环境效率及绿色效率的总体效率值分别为0.879、0.933、0.939,农业用水的绿色效率高于环境效率和经济效率,即农业用水产生了较好的社会效益。（2）近9年长江经济带11省市农业用水经济效率、环境效率及绿色效率总体平均值均呈轻微波动下降趋势,农业用水科学利用问题需得到进一步的重视。（3）长江经济带下游地区农业用水绿色效率均值最高,中游地区次之,上游地区最低。其中上海市农业用水绿色效率多年均值最高（1.206）,云南省最低（0.513）,地区差异较显著,但核密度估计显示2010—2018年区域内农业用水绿色效率差距在缩小,总体上呈均衡协调发展趋势。（4）城镇化水平、R&D占比、人均节水灌溉面积、单位国内生产总值耗水、人均教育财政支出、人均水资源量等是长江经济带农业用水绿色效率差异的主要影响因素。结论 研究长江经济带农业水资源绿色效率并探究其影响因素,可以为推动长江经济带农业用水绿色可持续利用提供某些参考。     

农业绿色发展政策的农户行为响应研究——以新疆X县为例

目的 通过对农业绿色发展政策的农户行为响应机制分析和实证检验,发现其中存在的不足,以期完善农业绿色发展政策,促进农业绿色发展水平进一步提高。方法 文章基于新疆X县305份农户调查数据,运用计划行为理论构建农业绿色发展政策农户行为响应研究的理论框架,探索农业绿色发展政策与农户行为之间的运行机理,并采用结构方程模型对构建的理论假设进行验证。结果 （1）农户的“行为态度”“主观规范”和“行为控制”三个方面均显著影响农户农业绿色发展的行为意愿,且“行为态度”对农户农业绿色发展行为意愿的影响最大,主观规范的影响最小,行为控制居于二者之间;（2）农业绿色发展政策对农户进行农业绿色发展行为响应的影响比其对行为意愿的影响程度大。通过对比路径系数的大小,证实了行为意愿在整个过程中起到了明显的中介作用;（3）农户农业绿色发展行为中,农户对约束类行为的响应程度比激励类行为高。结论 完善政策体系,加强农业绿色发展政策支持力度;做好政策宣传工作,增强农户农业绿色发展的行为意愿;“激励”与“约束”并用,提高农户行为响应程度等对策建议。     

浅谈铁路工程招投标管理

铁路工程实行招投标活动有利于铁路建设市场的法制化、规范化,实行招投标的目的基本做到了市场竞争的公正、公开、公平。但是,我国的铁路工程招投标管理还存在不正当竞争行为,必须建立和完善招投标管理模式,规范招标投标程序,坚决杜绝不正当竞争行为的发生。这就要引入第三方交易平台,加大信息公开力度。