政府研发补贴促进企业创新了吗

政府补贴能否促进企业创新一直存在争议。与以往从资源视角探讨政府补贴与企业创新关系的研究不同，基于信号理论视角，以2012—2016年沪深A股非金融类上市公司为研究样本，通过剔除非研发补贴的噪音并控制样本自选择偏误，实证检验中国转型经济背景下，政府研发补贴对企业创新的微观政策效应，以及企业层面制度因素（产权性质）和区域层面制度因素（制度环境）对该效应的调节作用。研究发现，政府研发补贴释放的积极信号能够帮助企业获取外部创新资源，有效促进企业创新；相比于国有企业，政府研发补贴对非国有企业创新的激励效应更强；制度环境越好，政府研发补贴对企业创新的激励效应越强。研究理论丰富了科技创新政策有效性和信号理论相关研究。同时，研究发现，政府应继续加大对企业创新活动的补贴额度，不断深化所有制改革，为企业创新营造良好的外部制度环境；另外，企业还应充分发挥政府研发补贴信号的杠杆效应，拓宽外部创新资源获取渠道。     

Preventing motor vehicle crash injuries and deaths: science vs. folklore lessons from history

Abstract

Not long after the beginnings of motorization in the early 1900s, deaths and injuries from motor vehicle crashes became a problem in a number of high-income-countries (HIC)s, especially the United States. With the biggest problem the US led early efforts to address this issue, and for six decades these efforts were based on folklore (ie a body of widely held but false or unsubstantiated beliefs). They were not evaluated, but clearly were unsuccessful as crash deaths and injuries continued to rise. It was not until the 1970s that a broader range of countermeasures began to be adopted and was scientifically evaluated, and as a result, crash deaths and injuries declined. This history has important lessons today for many low-and-middle-income countries that have growing numbers of motor vehicle crash deaths and injuries, many of which are pedestrians and motorcyclists. This is because there continue to be advocates for many of the failed approaches (especially educational) that dominated the early efforts in HICs.     

Promotion and Prevention Contracts in Industry Level Firm to Firm Dyad

ABSTRACT

Purpose

This article aims to introduce and distinguish two features of contract design – prevention and promotion contracts – and compares their effects on opportunism within the distributor–supplier relationship. It also examines the moderating role of ex post contract enforcement strategies.     

微纳卫星组网星间链路设计及关键技术分析

微纳卫星组网应用可大幅度提高航天装备的能力，较单颗大卫星具有明显的优势。首先，介绍了国内外微纳卫星组网的研究情况，以组网侦察应用为例分析了星间测量与通信链路的技术需求，并进行了系统架构和体制设计；其次，在星座设计基础上开展系统仿真，并提出了一体化设备实现方案；最后，分析了微纳卫星组网系统中几项重要的关键技术及其解决方案，对系统的设计和工程实现具有参考价值。     

Does high‐speed rail connection really promote local economy? Evidence from China’s Yangtze River Delta

High‐speed rail (HSR) has led to a transportation revolution in China. This paper uses the county‐level panel data of China’s Yangtze River Delta to investigate the effect of HSR connection on local economy. To address the issue of endogenous HSR route placement, we use a straight‐line strategy to construct potential HSR connection variables as instrumental variables of the actual HSR connection. Both the difference‐in‐differences and instrumental variable methods show that HSR connection impedes local economy, especially in peripheral regions. The impediment effect is channeled through population reallocation from peripheral to core areas and the restructuring of industries.     

Is faster or slower trading better? An examination of order type execution speed and costs

We examine order type execution speed and costs for US equity traders. Marketable orders that execute slower exhibit lower execution costs. Those who remove liquidity faster and pay higher trading costs transact in smaller size, spread trading across more venues, take more liquidity, and are better informed. Nonmarketable limit orders that execute slower exhibit greater adverse selection; and larger, uninformed traders who concentrate their trading in fewer venues submit them. Our findings suggest that slowing down the trading process, when faster options exist, can benefit certain market participants who seek to cross the bid–ask spread.     

Impact of walking speed on tourist carrying capacity: The case of Maiji Mountain Grottoes,China

This paper analyzes the impact of walking speed on tourist carrying capacity. To do so, a combination of simulation experimentation and on-the-ground experiment is suggested to work in a study case, Maiji Mountain Grottoes, China. The simulation findings indicate that walking speed has a negative impact on tourist carrying capacity and the correlation coefficient is 0.64, for the reason that walking takes up more space. The on-the-ground experiment shows that carrying capacity is not a unified limit all over a destination, but changeable temporally and spatially, and its estimation needs to be adjusted according to the minimum area required per tourist and tourist activity. The method applied in this paper and the simulation findings can serve as a methodological tool for further research about tourist carrying capacity where the main activity of tourists is walking while watching.     

创新政策工具组合、创新能力与创新绩效研究

基于2008-2018年我国内地30个省市面板数据，采用面板固定效应模型分析创新政策工具及其交互项对创新能力及创新绩效的影响。结果发现：①供给型和环境型创新政策均有利于促进技术创新能力提升和创新数量增长，需求型创新政策对创新能力及创新绩效的影响均不显著；②需求型、环境型和供给型创新政策两两交互项能够显著提高基础创新能力和技术创新能力，并显著增加创新数量，但对创新质量均呈显著负向影响；③需求型与供给型以及需求型与环境型创新政策组合功能呈协同互补性特征，供给型和环境型创新政策组合功能呈竞争性特征；④基础创新能力在创新政策工具对创新质量的影响中发挥完全中介作用，技术创新能力在创新政策工具对创新数量的影响中发挥完全中介作用。     

Probabilistic wind forecasting up to three months ahead using ensemble predictions for geopotential height

We develop a method for forecasting the distribution of the daily surface wind speed at timescales from 15-days to 3-months in France. On such long-term timescales, ensemble predictions of the surface wind speed have poor performance, however, the wind speed distribution may be related to the large-scale circulation of the atmosphere, for which the ensemble forecasts have better skill. The information from the large-scale circulation, represented by the 500 hPa geopotential height, is summarized into a single index by first running a PCA and then a polynomial regression. We estimate, over 20 years of daily data, the conditional probability density of the wind speed at a specific location given the index. We then use the ECMWF seasonal forecast ensemble to predict the index for horizons from 15-days to 3-months. These predictions are plugged into the conditional density to obtain a distributional forecast of surface wind. These probabilistic forecasts remain sharper than the climatology up to 1-month forecast horizon. Using a statistical postprocessing method to recalibrate the ensemble leads to further improvement of our probabilistic forecast, which then remains calibrated and sharper than the climatology up to 3-months horizon, particularly in the north of France in winter and fall.     

房地产经济与国民经济协调发展速度预测

采用线性规划与投入占用产业模型相结合的方法,把国民经济划分为25个部门,以投入占用产出模型为基础,附加约束条件,形成综合数学规划模型,作为增长速度的预测模型。