乡村振兴导向下乡村发展能力的多维测度及时空交互特征

乡村振兴要求走乡村内生性发展道路,客观认知乡村发展能力的时空分异格局和交互关系对乡村振兴战略实施具有重要意义。本文从农业产业发展、农村基础建设和农民社会生活三个维度构建测度指标体系,并引入面板向量自回归模型识别影响乡村发展能力的敏感因素,以此测度乡村发展能力指数,进而采用探索性时空数据分析方法揭示乡村发展能力的时空交互特征。结果表明：(1)我国中部地区多维乡村发展能力提升,但呈明显的空间异质性,不同维度间差异化显著;(2)中部地区多维乡村发展能力局域空间格局呈现较强的动态性并整体表现出较强的空间依赖关系;(3)邻接地级市多维乡村发展能力的时空交互网络以正向关联为主,局部空间呈差异化的竞合态势。     

The ripple effects of large-scale transport infrastructure investment

We analyze the general equilibrium effects of an asymmetric decrease in transport costs, combining a large-scale spatial dynamic general equilibrium model for 267 European NUTS-2 regions with a detailed transport model at the level of individual road segments. As a case study, we consider the impact of the road infrastructure investments in Central and Eastern Europe of the European Cohesion Policy. Our analysis suggests that the decrease in transportation costs benefits the targeted regions via substantial increases in gross domestic product (GDP) and welfare compared to the baseline, and a small increase in population. The geographic information embedded in the transport model leads to relatively large predicted benefits in peripheral countries such as Greece and Finland, which hardly receive funds, but whose trade links cross Central and Eastern Europe, generating profit from the investments there. The richer, Western European nontargeted regions also enjoy a higher GDP after the investment in the East, but these effects are smaller. Thus, the policy reduces interregional disparities. There are rippled patterns in the predicted policy spillovers. In nontargeted countries, regions trading more intensely with regions where the investment is taking place on average benefit more compared to other regions within the same country, but also compared to neighboring regions across an international border. We uncover that regions importing goods from Central and Eastern Europe enjoy the largest spillovers. These regions become more competitive and expand exports, to the detriment of other regions in the same country.     

Innovation across cities

This paper examines the distribution of patenting activity across cities in the OECD, using a sample of 218 cities from 2000 to 2008. We obtain three main results. First, patenting activity is more concentrated than population and GDP. Second, patenting activity is less persistent than population and GDP, especially in the middle of the distribution. Third, in a parametric model, patenting does not exhibit mean‐reversion, and is positively associated with GDP and population density. Our results suggest that policymakers can influence the amount of innovative activity through the use of appropriate policies.     

Urban size and KIBS vertical disintegration: the case of Milan

The literature shows that market size favours firms’ vertical disintegration because it reduces transaction and knowledge coordination costs. The existing evidence is based primarily on cross-sectional data and on the manufacturing sector, with little or no attention is given to longitudinal data and services. This paper estimates the effect of urban size on the purchase of service inputs by knowledge-intensive business service firms located in the metropolitan region of Milan. Relying on a rich panel dataset, and adopting different econometric techniques to overcome endogeneity, we find a positive and statistically significant effect of increased urban population on the degree of KIBS vertical disintegration only when urban size is measured at the province level. We also find that this effect holds particularly in the case of traditional professional- rather than technology-related activities.     

Stable Isotopes,Chronology, and Bayesian Models for the Viking Archaeology of North-East Iceland

This paper reviews the results of a long-term research project that used stable isotope analyses (δ¹³C, δ¹⁵N, δ³⁴S) and Bayesian mixing models to better model the chronology for a presumed Viking Age cemetery at Hofstaðir, near Lake Mývatn in north-east Iceland. δ¹³C and radiocarbon dating indicated that many of the individuals consumed a large amount of marine protein, which results in a marine reservoir effect (MRE), making ages older than expected. In addition to the MRE, geological activity in the region has the potential to introduce massive quantities of radioactive ‘dead’ carbon into the freshwater system, resulting in a very large freshwater reservoir effect (FRE) that can offset radiocarbon ages on the order of a few thousand years. The radiocarbon dates of organisms that derive an unknown proportion of their carbon from both marine and freshwater reservoirs are extremely difficult to ‘correct’, or, more appropriately, model. The research not only highlights the complexities of dealing with multiple reservoirs, but also how important it is to develop models that are temporally and geographically relevant to the site under study. Finally, it shows how this data can be used to inform the development of chronological models for refining the dating for archaeological activity.     

How Political Support Influences Red Tape through Developmental Culture

This study examines the interrelationship between external political support, internal organizational factors, and red tape, using a sample of information managers from state health and human service agencies. The study defines a red tape model and tests the model by structural equation modeling method. The study finds that political support has a direct effect on red tape. The higher the political support, the lower the level of red tape. The study also confirms an indirect effect of political support on red tape, mediated by developmental culture. Indirect effect through goal clarity has the correct sign but is not statistically significant. Practical recommendations are made for the political environment to provide the opportunity for managerial reforms that are often advocated.     

考古地层的三维建模方法在秦始皇帝陵考古勘探中应用尝试

为了更清楚地展示秦始皇帝陵地区考古地层的三维空间关系,并为后期考古工作中空间数据挖掘做准备,借鉴三维地质建模技术,提出了考古地层三维建模方法。基于探孔数据构建了考古地层三维模型。该模型清楚地展示了秦始皇帝陵地区考古地层的三维空间关系,为田野考古数字化工作提供一种新思路、新方法。     

部门管理人员感知的组织支持与组织氛围对旅游企业员工角色压力的影响

欧美学者普遍认为,角色压力是影响员工服务态度和服务行为的一个极为重要的因素,包括角色负担、角色冲突、角色模糊等3个组成成分.本文对我国11个地区的33个旅游企业进行了一次实证研究,检验部门管理人员感知的组织支持、企业的支持型领导氛围、授权氛围和员工服务行为评估氛围对员工角色模糊的影响.多层次线性模型分析结果表明,部门管理人员感知的组织支持会通过企业的支持型领导氛围,间接影响员工感知的角色模糊.企业的支持型领导氛围会通过企业的授权氛围,间接影响员工感知的角色模糊.此外,部门管理人员感知的企业支持还会调节员工感知的角色负担和角色冲突对他们的角色模糊的影响.     

Precipitation of lead–zinc ores in the Mississippi Valley‐type deposit at Trèves,Cévennes region of southern France

The Trèves zinc–lead deposit is one of several Mississippi Valley‐type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ³⁴S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to ?21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur‐rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced sulfur concentration on the Zn and Pb transport capacity of the ore fluid and the volumes of fluid required to form the deposit. The studies of the Trèves ores provide insights into the ore‐forming processes of a typical MVT deposit in the Cévennes region. However, the extent to which these processes can be extrapolated to other MVT deposits in the Cévennes region is problematic. Nevertheless, the evidence for the extensive migration of fluids in the basement and sedimentary cover rocks in the Cévennes region suggests that the ore forming processes for the Trèves deposit must be considered equally viable possibilities for the numerous fault‐controlled and mineralogically similar MVT deposits in the Cévennes region.     

Phase‐field modeling of epitaxial growth of polycrystalline quartz veins in hydrothermal experiments

Mineral precipitation in an open fracture plays a crucial role in the evolution of fracture permeability in rocks, and the microstructural development and precipitation rates are closely linked to fluid composition, the kind of host rock as well as temperature and pressure. In this study, we develop a continuum thermodynamic model to understand polycrystalline growth of quartz aggregates from the rock surface. The adapted multiphase‐field model takes into consideration both the absolute growth rate as a function of the driving force of the reaction (free energy differences between solid and liquid phases), and the equilibrium crystal shape (Wulff shape). In addition, we realize the anisotropic shape of the quartz crystal by introducing relative growth rates of the facets. The missing parameters of the model, including surface energy and relative growth rates, are determined by detailed analysis of the crystal shapes and crystallographic orientation of polycrystalline quartz aggregates in veins synthesized in previous hydrothermal experiments. The growth simulations were carried out for a single crystal and for grain aggregates from a rock surface. The single crystal simulation reveals the importance of crystal facetting on the growth rate; for example, growth velocity in the c‐axis direction drops by a factor of ~9 when the faceting is complete. The textures produced by the polycrystal simulations are similar to those observed in the hydrothermal experiments, including the number of surviving grains and crystallographic preferred orientations as a function of the distance from the rock wall. Our model and the methods to define its parameters provide a basis for further investigation of fracture sealing under varying conditions.