南方丘陵区新增耕地质量空间特征研究*——以江西省宜春市为例

［目的］粮食安全的根本是在耕地，关键在于耕地质量。目前新增耕地主要源于土地开发项目、城乡建设用地增减挂钩土地复垦项目等，这些新增耕地需要对其开展耕地质量等别评定工作，了解新增耕地的质量状况，分析其空间特征，这对落实国家耕地保护制度、开展农村土地整治工作等具有重要作用。［方法］文章以南方典型丘陵区域——江西省宜春市作为研究区域，在新增耕地质量评价的基础上，运用地统计学、景观生态学、Arcgis空间分析技术和典型相关分析方法，研究宜春市新增耕地质量的空间特征，掌握耕地质量等别的分布规律，了解耕地质量的影响因素，为制定合理的耕地资源利用与保护政策提供依据。［结果］（1）Moran′s I值结果表明宜春市2014年新增耕地利用质量在空间分布上的空间自相关性最强，而耕地自然质量空间自相关性最弱。（2）景观破碎度指数结果表明优、高等别的新增耕地质量破碎度大于中、低等别的； 多样性指数结果表明新增耕地质量多样性指数比较大； 优势度指数结果表明新增耕地质量等别优势度指数比较小，与多样性指数结果相呼应； 均匀度指数结果表明，新增耕地质量等别均匀度指数相差不大，新增耕地质量等别比较均匀。（3）质心结果表明2013—2014年间宜春市新增耕地质量的格局整体上是向西南方向变化。［结论］宜春市新增耕地质量不高； 新增耕地的利用水平差异性较小，自然本底状况差异较大； 新增耕地质量等别类型多，各质量等别类型耕地均有增加，耕地质量参差不齐，较高等地的新增耕地相对低等地而言更破碎化； 新增耕地的开发格局向着西南方向移动； 该研究为南方丘陵区的新增耕地保护提供了一定的参考依据。     

Does local government competition aggravate haze pollution? A new perspective of factor market distortion

Haze pollution has become a new threat to China's sustainable development, but it may be that local government behaviour can play an important role in the prevention and control of pollutants. A dynamic spatial autoregressive (SAR) model is used to study the relationship between local government competition and haze pollution. To further explore the indirect impact of factor market distortion on haze pollution and control potential endogeneity problems, a newly developed intermediary effect model that incorporates the characteristics of the generalized method of moments (GMM) is utilized to explore how factor market distortion indirectly affects haze pollution. The research results show that regional haze pollution in China is characterized by significant spatial correlation, and local government competition has a positive impact on haze pollution; that is, local government competition exacerbates haze pollution. In general, local government competition not only directly leads to an increase in haze pollution but also further intensifies it by distorting the local factor market, and the intermediary role of factor market distortion is approximately 7.04%. The results of the regional inspection found that competition among local governments in the eastern region did not lead to haze pollution, and distortion of the factor market did not exist as an intermediary effect. However, both direct and intermediary effects are significant in the central and western regions. Therefore, an official performance appraisal system that includes ecological constraints should be established to guide the benign transformation of local government competition, and an environmental management mechanism must be developed for joint prevention and control to reduce haze pollution. In addition, the free flow of factors and marketization are equally important.     

Can stable environmental protection officials’ tenure reduce illegal emissions?

Based on the day-night PM_2.5 difference of the nearest atmospheric monitoring points to measure whether there is illegal emission, this paper explores the impact of environmental protection officials' tenure (EPLT) on illegal emissions. The results show that there is a positive correlation between EPLT and illegal emissions. Stable EPLT can reduce illegal emissions by increasing environmental information disclosure and environmental subsidies. It can increase illegal emissions by weakening public pollution reporting and media supervision, environmental law enforcement and promoting corruption. In addition, EPLT can increase illegal emissions as EPLT is less than 3.55 years, while EPLT can increase illegal emissions as EPLT exceeds 6.21 years. Further, when mayor's tenure and EPLT are both stable, the promotion effect of EPLT on illegal emission is stronger. Stable company director's tenure can also aggravate the promotion effect of EPLT on illegal emissions.     

Environmental Taxation and Vertical Cournot Oligopolies: How Eco-industries Matter

This article specifies what an optimal pollution tax should be when dealing with a vertical Cournot oligopoly. Polluting firms sell final goods to consumers and outsource their abatement activities to an environment industry. It is assumed that both markets are imperfectly competitive. Thus, the tax is a single instrument used to regulate three sorts of distortions, one negative externality and two restrictions in production. Consequently, the optimal tax rate is the result of a trade-off that depends on the firms’ market power along the vertical structure. A detailed analysis of Cournot-Nash equilibria in both markets is also performed. In this context, the efficiency of abatement activities plays a key-role. It gives a new understanding to the necessary conditions for the emergence of an eco-industrial sector.      

Pollution Control in Open Economies: Implications of Within-period Interactions for Dynamic Game Equilibrium

This paper examines a two-country, dynamic game model of pollution control in the presence of economic interactions between countries within a period, as well as the environmental interaction between periods (i.e., a change in the stock of global pollution). These economic interactions emerge because of changes in the terms of trade of polluting goods or the market share of domestic polluting industries. It is shown that if within-period externalities exist, a noncooperative equilibrium may result in a smaller stock of global pollution in the steady state than does international cooperation. Moreover, the properties of equilibrium paths depend on the direction and size of such externalities. In addition, trigger strategy equilibria that achieve the outcome of the collusive solution are examined.     

Ambient Taxes Under m-Dimensional Choice Sets, Heterogeneous Expectations, and Risk-Aversion

We consider the design of ambient taxes forrisk-neutral and risk-averse polluters whenpolluters and the regulatory agency haveasymmetric information about environmentalrelationships and probabilities associatedwith random events. Unlike prior work, we showthat under these conditions, optimal ambienttaxes must be firm-specific, and accompaniedby additional incentives to influencepolluters' choices of abatement techniques.     

Study on formation mechanisms of Gannan navel orange characteristic industrial clusters on organizational ecology

The planter history of Gannan navel orange might trace to 1970s, up to now underwent in more than 30 years. Approximately, the development historical division on the Gannan navel orange is 4 stages. The natural environment factor, the customer factor, and the political factor have played crucial roles in the formation and development of GNOCIC. Among them, the rich natural resource and the superior geographical environment are the material base. And government＇s support is the main propelling force. The customers＇ expense is the final decision strength by chance which it develops, expands.     

Prevention versus Treatment under Precautionary Regulation: A Case Study of Groundwater Contamination under Uncertainty

Policy discussions on agricultural pollution problems characterize prevention as more cost effective and precautionary than ex post treatment. We derive conditions under which treatment alone is more cost effective in situations involving multiple sources of emissions, multiple sites affected, and a commonly used precautionary approach to uncertainty. We also show that a greater degree of precaution can result in less reliance on prevention. An empirical case study indicates that treatment alone is the most cost-effective means of dealing with nitrate in most Maryland community water system wells. The use of leaching prevention measures is restricted to the most intensive poultry producing areas. The incremental cost of precaution is substantial.     

On modeling incentive systems which utilize pollution charges for pollution abatement

This paper examines a scheme of economic incentives for environmental protection, in which spatially differentiated pollution taxes are in use in compensating the pollution abatement costs. A simple mathematical model is described which determines an incentive system that encourages polluters to reduce the discharges to an acceptable level of ambient quality standards in a cost-effective manner. It is shown that the vector of pollution charges has to be proportional to the marginal abatement cost vector, but is smaller than the latter in magnitude. It is demonstrated that a necessary incentive effect may be achieved even if the total pollution charge is much lower (about three times) than the total abatement costs. It is also estimated how this charge incentive system reconciles conflicting criteria of cost-effectiveness and of equity. These conclusions are verified by numerical experiments with real data.     

三维激光扫描仪在地形测量中的应用

文章从三维激光扫描仪在测量中的作用入手,详细介绍了三维激光扫描仪的工作原理和三维激光扫描系统,并说明了三维激光扫描仪配套三维数据处理软件的功能,着重介绍了三维数据的处理方法:点云的连接、特征线的提取、对地物的三维建模(TIN建模),在TIN建模中,介绍了狄洛尼三角网的构网方法。