Endogeneity and the Dynamics of Voluntary Disclosure Quality: Is there Really an Effect on the Cost of Equity Capital?*

Research on the effects of voluntary disclosure quality on the cost of equity capital is often plagued by endogeneity concerns. In this paper, I use a dynamic panel system GMM estimator, which provides internal instruments from the firm's history that directly address endogeneity arising from unobserved heterogeneity and simultaneity. By using hand-collected voluntary disclosure scores for firms listed in the Swiss stock exchange, I examine the dynamic relation between voluntary disclosure quality and the cost of equity capital in a panel over a period of 10 years. The results suggest that the relation between voluntary disclosure quality and the cost of equity capital becomes insignificant after controlling adequately for potential dynamic endogeneity, simultaneity, and unobserved heterogeneity.     

农业增长与环境污染的动态分析*——基于2006—2015年面板数据的验证

［目的］近年来，我国农业面源污染形势严峻，已经成为现代农业发展的瓶颈。文章主要分析农业面源污染与经济增长的关系，寻求解决农业面源污染问题的有效方法，在一定程度上为我国农业可持续发展和环境治理提出相关政策建议。［方法］选取2006—2015年全国31个省（省份、自治区）的面板数据，以农药、化肥、塑料薄膜流失量作为农业污染排放的主要指标，建立简约式模型考察农业环境的库茨涅茨曲线特征。［结果］（1）农业环境库茨涅茨曲线在我国基本得到支持。化肥流失量、农药流失量、塑料薄膜残留量与农业总产值间均存在显著的倒U 型曲线关系，除了山东、河南部分年份达到了农药、塑料薄膜污染方程的拐点之外，其余所有省份农业总产值均低于拐点值。（2）在方程中加入控制变量不影响模型的显著性，只是改变了转折点的出现。（3）城镇化水平的提高会减少农药、化肥的使用量但却增加了塑料薄膜的使用量。农业机械化拥有量系数不显著，农业技术进步环境效应并未得到充分发挥。［结论］十三五时期我国农业整体污染程度还会进一步加深，要想真正达到农业产出增长与环境相互协调的目的，必须同时从农业污染和农业要素投入两个方面着手。     

Heterogeneity of Long‐run Technical Efficiency of German Dairy Farms: A Bayesian Approach*

In parametric efficiency studies, two alternative approaches exist to provide an estimate of the long‐run efficiency of firms: the dynamic stochastic frontier model and the generalised true random‐effects model. We extend the former in order to allow for heterogeneity in the long‐run technical efficiency of firms. This model is based on potential differences in firm‐specific characteristics and in firms’ inefficiency persistence. The model is applied to an unbalanced micro‐panel of German dairy farms over the period 1999 to 2009. Estimation of long‐run technical efficiency and inefficiency persistence is based on an output distance function representation of the production technology and estimated in a Bayesian framework. The results suggest that heterogeneity in long‐run technical efficiency of farms is mostly attributed to discrepancies in farm‐specific factors rather than differences in farms’ inefficiency persistence. Farm size is positively related to long‐run technical efficiency while subsidies exert a negative effect on the long‐run technical efficiency of farms. Inefficiency persistence is found to be very high, but heterogeneity in this persistence is low.     

客家乡村旅游发展时空演变及其动力机制研究

[目的]以客家核心区梅州市为例,探讨客家乡村旅游时空演变及其动力机制,以其为客家乡村旅游开发提供理论支持。[方法]运用计量地理法和GIS空间分析技术,从时间与空间两个维度上对客家乡村旅游时空演变及其动力机制进行分析。[结果]结果表明:时间维度上,客家乡村旅游发展阶段性特征鲜明,经历了萌芽、兴起和蓬勃发展3个阶段。空间维度上,客家乡村旅游点空间分布类型由均匀型向凝聚型演变,并呈集中分布,且随着时间的推移,集中程度呈现逐渐增大趋势。在此基础上探讨了影响客家乡村旅游时空演变的动力机制,其主要来源于外生和内生动力两方面;外生动力包括市场驱动力、政策驱动力和交通驱动力,内生动力包括资源驱动力、品牌驱动力和村落拯救驱动力。针对研究结果对客家乡村旅游发展从市场挖掘、政府支持和保护性开发等方面提出了相应的启示性建议。[结论]客家乡村旅游发展迅速,对其时空演变特征及动力机制的深入认识有利于进一步做好客家乡村旅游开发,促进客家乡村振兴。     

基于扎根理论的产学研协同创新路径演化的动因研究

积极推行产学研协同创新是中国实现自主创新、打造创新驱动发展型国家的关键，因此，有关产学研协同创新路径演化的动因研究就具有理论意义和实践价值。运用经典扎根理论的研究方法，借助两个较为典型的国家级协同创新中心作为研究对象，深入分析影响产学研协同创新路径演化的根本动因，最终抽象出了创新控制力这一新的概念。     

组织创新、技术创新及二者交互匹配对企业绩效的动态影响研究——以高技术企业为例

从动态视角，深入探究组织创新与技术创新匹配关系对企业绩效影响的及时性和滞后性。具体通过构建由组织创新、技术创新、二者交互匹配与企业绩效四个变量组成的SVAR模型，通过检验表明不同变量间存在长期的均衡与因果关系。进一步运用脉冲响应分析和预测方差分解法，深入剖析不同变量间的长期动态影响关系。研究结果表明，企业绩效在短期内受自身一定程度的影响，技术创新对企业绩效的正向影响具有及时性和持续性，组织创新对企业绩效却产生滞后与深远的正向效应，而二者交互匹配对企业绩效的影响具有及时性和持续性。长期来看，三者分别对企业绩效产生动态、持续的正向效应，组织创新与技术创新分别对企业绩效的贡献度趋于一致，确保二者协调、有效匹配，共同带动企业绩效的持久、稳定增长。     

Risk spillovers between cryptocurrencies and traditional currencies and gold under different global economic conditions

This paper applies a Diagonal BEKK model to investigate the risk spillovers of three major cryptocurrencies to ten leading traditional currencies and two gold prices (Spot Gold and Gold Futures). The daily data used are from 7 August 2015 to 15 June 2020. The dataset is analyzed in its entirety and is also subdivided into four distinct subsets in order to study and compare the patterns of spillover effects during economic turmoil, such as the 2018 cryptocurrency crash and the COVID-19 pandemic. The results reveal significant co-volatility spillover effects between cryptocurrency and traditional currency or gold markets, especially during the whole sample period and amid the uncertainty raised by COVID-19. The capabilities of cryptocurrency are time-varying and related to economic uncertainty or shocks. There are significant differences between normal and extreme markets with regard to the capabilities of cryptocurrency as a diversifier, a hedge or a safe haven. We find the significant co-volatility spillover effects are asymmetric in most cases especially during the COVID-19 pandemic period, which means the negative return shocks have larger impacts on co-volatility than positive return shocks of the same magnitude. Evidently, cryptocurrencies and traditional currencies or gold can be incorporated into financial portfolios for financial market participants who seek effective risk management and also for optimal dynamic hedging purposes against economic turmoil and downward movements.     

城乡统一建设用地市场形成的动力机制研究

"土地城镇化"模式下城乡土地利益结构失衡问题日趋严重,强制性构建城乡统一建设用地市场的目标在短期内较难实现,而在诱致性制度变迁的推动下,由农民自发组成、得到政府支持、有限度的城乡统一建设用地市场是可能的。文章从制度变迁的博弈均衡视角出发,结合地方政府与中央政府、开发商、农村基层政权和农民四组博弈,探讨推动城乡统一建设用地市场形成的动力机制,为其破除制度障碍和减少改革阻力提供理论基础。     

带阻尼器拉索结构的索力识别研究

为解决带多个阻尼器索结构的索力识别问题,依据动力学相关理论,建立带3个减振器的拉索-减振器动力学模型,推导其频率方程,构造相应的无量纲参数并进行参数分析.结果表明:随着减振器支撑刚度的增加,无量纲振动频率逐渐增大,但这种增大趋势随支撑刚度的继续增加而趋于平缓;随着减振器安装距离的增加,无量纲振动频率逐渐增大,且这种趋势接近线性变化.最后利用有限元分析软件ANSYS并分别采用LINK单元与BEAM单元对其结论进行验证.     

江苏省人口老龄化影响产业结构优化的动力机制——基于积极老龄化视角

论文从积极老龄化视角分析人口老龄化对区域产业结构优化的影响,分别从劳动力供给、消费需求变化、居民储蓄等方面研究人口老龄化对产业结构优化影响中的抑制或推动作用。研究结果显示:积极老龄化视角下,人口老龄化在人才培养、产业结构匹配、产业集聚等方面能够促进产业结构优化。