VOLUNTARY WORK AND WAGES

The effects of voluntary work on earnings have recently been studied for some developed countries such as Canada, France and Austria. This paper extends this line of research to Italy, using data from the European Union Statistics on Income and Living Conditions (EU‐SILC) dataset. A double methodological approach is used in order to control for unobserved heterogeneity: Heckman and IV methods are employed to account for unobserved worker heterogeneity and endogeneity bias. Empirical results show that, when the unobserved heterogeneity is taken into account, a wage premium of 2.7 percent emerges, quite small if compared to previous investigations on Canada and Austria. The investigation into the channels of influence of volunteering on wages gives support to the hypotheses that volunteering enables the access to fruitful informal networks, avoids the human capital deterioration and provides a signal for intrinsically motivated individuals.     

旅游产业竞争潜力构成及其影响变量分析

伴随着旅游产业竞争的日益国际化和激烈化,如何增强旅游产业竞争力以便在旅游市场竞争中取胜已成为各旅游目的地发展战略中需要重点解决的问题。而从持续竞争优势的角度来看,不仅需要关注旅游产业现实竞争力,更要关注旅游产业竞争潜力,因为在一定外力的推动作用下潜力可以转化为竞争力。本文针对现有潜力研究中只关注供给而忽略需求要素的不足,提出从供需两方面分析旅游产业潜力体系的构成及其影响变量,揭示出旅游产业潜力构成是一个多层次、多要素的有机结合体,从而为将旅游产业潜力与竞争力进行联动机理分析、并为提升我国旅游产业竞争力对策建议提供了一个更全面的分析视角。     

Operators are not Parameters, the Dimensions of Operators and Variables Must be Invariant, and Indices may not be Dimensioned: Rejoinder to Professors Folsom and Gonzalez

What is certain is that mathematics cannot possibly be a valid means (to advances in economic understanding) unless and until it is used properly. That means that dimensions must be used consistently and correctly. Barnett (Barnett, Quart J Austrian Econ, pp. 27–46, 2003) is about problems with the use of mathematics in economics involving the failure to use dimensions/units consistently and correctly. Professor Emeritus Folsom and Professor Gonzalez (Folsom and Gonzalez, Quart J Austrian Econ, pp. 45–65, 2005), hereinafter F&G, say, essentially, that what is correct therein is not new and that what is new is not correct. Additionally, they imply, by raising them, that I did not address issues that I should have, e.g., how to introduce dimensions into introductory economics and problems with the Cobb-Douglas (CD) function unrelated to dimensions. Herein, because of space limitations, I respond only to some of their criticisms. Responses to others are posted on the Ludwig von Mises Institute Working Papers site.

Volatility in Cereal Prices: Intra‐ Versus Inter‐annual Volatility

Intra‐annual (within crop year) price volatility and inter‐annual (between crop years) price volatility are measured for wheat, maize, rice, barley, oats and rye. A set of explanatory variables is used in a pooled regression to explain variations in these price volatilities. With low cereal stocks, supply (yield) shocks (defined here as volatilities, as for the price volatilities) mostly influence inter‐annual volatility while other influential factors are the crude oil price and exchange rate. Cereal demand and interest rate shocks combined with low stocks affect intra‐annual volatility, while other explanatory factors include exchange rate and crude oil price shocks. The derivatives market activity appears to have no significant effect on either intra‐ or inter‐annual volatility. In contrast, large cereal stocks and a well‐functioning international cereal market reduce the effects of shocks in the explanatory variables on both intra‐ and inter‐annual volatilities.     

公司治理内生性研究述评与展望

近年来,公司治理领域的研究取得了丰硕成果,但对于公司治理内生性的研究还缺乏系统性。首先从理论上对公司治理内生性进行了介绍,然后从实证研究角度对公司治理内生性进行了详细阐述,指出了工具变量法与2SLS关系,丰富了公司治理内生性研究。在此基础上,对以往公司治理内生性研究进行了梳理与评析,并对公司治理内生性研究的未来发展趋势进行了展望。     

多元函数关于直线的对称性研究

本文给出了n维欧氏空间中点关于直线的对称点的坐标,对多元函数关于直线的对称性作了探讨,并给出了多元函数关于直线对称的充要条件。     

军事物流储备中离散变量的信息熵模型的研究

军事物流储备是我军后勤保障力量的一个重要组成部分。本文首先研究了离散变量的信息熵模型,然后结合部队的实际案例来探讨对于离散变量如何确定最佳的物资储量。     

土地流转对农户多维相对贫困的影响及机制研究 ——基于生产资源优化配置视角

研究目的：探讨土地流转对农户多维相对贫困的因果影响、作用机制及异质性,为进一步深化农村土地制度改革、构建缓解农村相对贫困的长效机制提供实证依据和有益启示。研究方法：利用2010—2018年中国家庭追踪调查数据,构建了多维相对贫困评价指标体系,通过BP神经网络赋权模型和双界限法测度农户多维相对贫困状况,然后使用工具变量法探讨土地流转对农户多维相对贫困的影响及作用机制。研究结果：（1）土地流转显著减轻了农户的多维相对贫困状况,且土地流出对5个子维度的相对贫困均存在稳健的减贫作用,而土地流入的减贫效应主要集中于家庭可行能力、发展机会、社会保险3个维度。（2）土地流转主要通过优化农户的土地和劳动力资源配置实现多维度的减贫效应。（3）土地流转对西部地区和农业产值较低县域的农户,以及家庭劳动力年龄较低和土地价值较低的农户的减贫效应更为明显。研究结论：土地流转有助于提升相对贫困群体的内生动力,培育自我发展的长效机制,其福利效应可以缩小地区间和人群间差异。基于此,为实现共同富裕的发展目标,需要进一步建立健全统一的土地经营权流转市场,促进土地规范有序流转。     

对我国各地区对外开放度适宜性的实证分析

本文采用两阶段最小二乘估计的方法,根据开放度与市场规模在对经济增长影响上的替代性理论,对我国各地区对外开放度的适宜性进行了实证分析,通过计算得出结论,上海、北京和广东等地区的贸易开放度已经偏高了,这些地区对外贸易的增长速度不应继续高于经济增长的速度,应维持或减小开放度;而其他地区的开放度离临界开放度尚远,可以继续通过提高对外开放度的方式促进经济增长。     

上海期货交易所的涨跌停板制度对波动性的影响

本文通过对上海期货交易所的三个品种的涨跌停板制度进行检验,检验方法为:从收益率所拟和的ARMA模型中滤出残差,进行波动率的GARCH模型回归。波动率模型中加入了哑元变量来体现涨停板对后一日波动的影响。实证结果显示,铜、铝、天然橡胶的涨跌停板本应显著地使收益率的波动率减小的作用未检验出,相反却得到涨停板使三个品种显著波动率增大的检验结果。是否需要扩大涨跌停板,提高市场效率?检验结果带给我们如何使涨跌停板制度趋于合理化的思考。