城投债为何持续增长:基于新口径的实证分析

包括城投债在内的地方政府债务规模持续增长,是近年来我国经济社会运行中的一个突出现象。作者利用一套新口径(2006—2015年)的城投债基础数据库,克服Wind整理的城投债数据存在的诸多缺陷,并以此为基础,结合地级市财经变量及主要官员信息等,实证分析地方财政压力、官员晋升压力和城市发展压力对城投债扩张的影响。研究结果显示:(1)财政压力并非导致城投债扩张的主要原因;(2)受晋升压力影响,市委书记处于特定年龄段(55~58岁)的地级市更倾向于发行城投债并扩大城投债规模;(3)在承受较大发展压力(包括经济发展水平、工业化、城镇化和固定资产投资等方面的赶超压力)的地级市,晋升压力对城投债规模的刺激效应更为突出。而且,晋升压力和发展压力对城投债扩张的影响在主动负债和被动负债、债券资金用途、债券期限、政府担保、发行地是否属于城市群等方面呈现明显的异质性。上述研究发现为深刻认识中国地方政府债务问题,合理制定相关政策,以化解地方政府债务风险提供了科学依据。     

Exploring clinical metrics to assess the health impact of traffic injuries

In order to allow a deep knowledge of the nonfatal injuries, recently the European Commission adopted the maximum abbreviated injury scale classification which is based on medical diagnosis. This classification will open the door to a new source of information based on international hospital data such as diagnosis-related group and international classification of diseases. In this study, we seek to explore these clinical metrics, which are used to describe the diagnosis and the medical treatment, and to infer consequences of crashes mainly through the costs and severity. Therefore, statistical analyses were applied using generalized linear models selected depending on the type of response variable, i.e. discrete or continuous. Relationships between these metrics were identified revealing for instance that head is the region of the body associated with high severity as well as to higher health care costs. Additionally, a discussion is presented regarding study results and future developments of clinical metrics are pointed out.     

The (lack of) international harmonization of EU standards: import and export effects in developed versus developing countries

This article studies the effect of the lack of international harmonization in agri-food standards on international trade flows focusing on the European Union (EU). The EU is characterized by high level of protectionism, which makes it an ideal case study. We measure the differences in countries’ level of ‘protectionism’ by applying an index of aggregation of non-tariff measures to data on maximum residue levels on pesticides and veterinary drugs allowed by countries on agri-food products. The restrictiveness of countries standards’ is compared with the one imposed by the Codex Alimentarius, which is considered as non-protectionist. The EU emerges as the most rigorous standards setter. The higher standards imposed by the EU affect in particular imports from developing countries, while it facilitates its exports, irrespective of the level of development and standard restrictiveness set by the importing countries.     

Simultaneous-equation estimation with no instrumental variables

For a single equation in a system of linear equations, estimation by instrumental variables is the standard approach. In practice, however, it is often difficult to find valid instruments. This letter outlines a maximum-likelihood method that does not require instrumental variables; it is applied to the estimation of a demand function and an Engel curve.     

Estimating the impact of incidents on urban controlled-access highways: an empirical analysis

An empirical analysis is developed that quantifies the impact of different types of traffic incidents on the speed and maximum flow averages of vehicles on a controlled-access highway. The incident types considered include damage to highway infrastructure, vehicle rollover, crashes (into stationary objects), collisions (with moving vehicles), rain, fog, vehicle breakdowns, pedestrians on roadway, etc. Using real-world data from Chile’s most heavily used urban motorway/freeway, estimates of incident impacts on speed are generated using a multiple linear regression model incorporating instrumental variables to correct for endogeneity. Flow results are then generated using the fundamental traffic equation relating speed, flow and density. A ranking of the impacts on highway traffic of the different incident types based on incident frequency as well as impact size demonstrates that for the real case studied, the incidents with the greatest cumulative effect are (in order of magnitude) vehicle breakdown, collisions and rain.     

雾霾治理、地方政府竞争与全要素生产率

在将城市面板数据与中国工业企业面板数据进行匹配的基础上,本文就地方政府竞争下环境治理策略互动形式进行了检验,然后构建空间自滞后模型并运用两阶段最小二乘法探讨了雾霾治理对全要素生产率的本地影响及其空间溢出影响,进一步从资源配置效应、创新补偿效应和污染避难所效应三方面考察了雾霾治理的传导机制。结果表明,随着环保政绩考核的加入,地理邻近城市环境治理策略逐渐从“逐底竞争”转变为“模仿”形式,即邻近城市加强或放松治理,该城市也加强或放松治理强度,相对竞优模仿形式下雾霾治理更有助于促进本地、邻地全要素生产率的提高,且不同区域、行业和所有制企业存在差异。进一步探究原因,发现加强雾霾治理产生的资源配置效应和创新补偿效应有利于促进城市间全要素生产率提高,而雾霾治理产生的污染避难所效应不利于城市间全要素生产率提高。由此,本文提出完善雾霾联防联控机制、创新绿色经济发展方式,实现环境保护和经济发展良性互动的建议。     

转移支付下地方政府科技投入空间效应研究

基于1997-2014年省级面板数据,对我国地方政府科技投入的影响因素与空间效应进行了研究。结果表明：财政分权对科技投入具有积极作用,政府竞争与人力资本投入对科技投入具有抑制作用;当地政府财政分权对科技投入的影响会引起相邻地区出现积极模仿行为,对相邻地区的科技投入产生空间外溢正效应;政府竞争和人力资本投入对科技投入的影响会引起相邻地区出现消极模仿行为,对相邻地区的科技投入产生空间外溢负效应。地方政府有必要合理分配科技投入在财政支出中的比重,处理好政府竞争、人力资本投入与科技投入的关系。     

土地出让收入、地方财政支出对我国房价影响的区域差异性研究

利用2002～2011年30个省市面板数据分析土地出让收入、地方财政支出对我国房价影响的区域差异性。研究结果表明,东中西部三个区域的土地出让收入与地方财政支出对房价的影响均存在不同程度的时滞效应;短期内土地出让收入与地方财政支出对房价的作用效果并无显著的区域差异性,但就长期发展趋势来看,东部与西部地区仍以地方财政支出影响为主,而中部地区的情况却出现了逆转,土地出让收入对房价的刺激作用要显著大于财政支出。     

小波模极大值法在地震解释图像边缘检测中的应用

边缘作为图像的最主要特征,是图像视觉信息获取的重要内容。小波变换具有检测信号局域突变的能力,且可以结合多尺度信息进行检测,因此成为图像边缘检测的优良工具。基于信号与噪声在不同尺度下小波系数模的变化特征,可以通过检测小波变换系数模局部极大值点来提取图像的边缘特征。实际课题中将小波模极大值法应用于三维地震资料——相干切片图像的边缘检测中,证实了该方法能较准确地提取断层边缘,为下一步对断层的提取及解释提供有力保障。     

农村税费改革后县乡财力困难的解决对策

当前实施的农村税费改革取得了一定的成效，但也带来县乡两级政权财力资金困难问题。解决这一问题主要从以下三方面入手：一是精简机构，压缩行政管理支出；二是完善分税制，建立稳固的地方税收来源；三是完善地方政府的转移支付制度。