How to fight against southern pine beetle epidemics: An insurance approach

The southern pine beetle (SPB) is among the leading biological agents killing southern pine species in the eastern United States. In light of recognized spatiotemporal autocorrelation in SPB outbreaks, we devise a spatiotemporal block bootstrapping method that can be applied to analyze spatiotemporally dependent infestations. We also identify the relevant risk determinants and evaluate their impacts on the frequency of SPB outbreaks. For example, we find forest type, climate, and natural disasters like storm and forest management are all significantly associated with SPB risks. Using the results of a statistical model, we design a county-level group index insurance plan that generates estimates of actuarially fair premium rates for timber stands containing southern pine species. Given that no government-provided compensation scheme for SPB epidemics currently exists, application of this new insurance product could reduce forest owners losses. Our study offers an approach to analyzing and protecting against risks of other destructive pests affecting the timber sector.     

粮食主产区耕地健康产能评价 ——以河南省温县为例

研究目的:探寻适合中国新时代耕地产能评价的新理论与方法,界定耕地健康产能内涵,构建评价指标体系,并应用河南省温县验证。研究方法:基于"需求—功能—维度—要素—指标"理论框架,构建耕地健康产能评价指标体系,运用综合算法、"1+X"累加模型法、图层叠加法定量评价耕地健康产能。研究结果:(1)温县耕地产能和耕地健康诊断结果地域分异特征明显,以青峰岭为界,北部耕地产能和健康状况较南部好;(2)耕地健康产能整体状况良好,乡镇间差异明显;(3)耕地健康产能结果更多取决于耕地健康诊断,主要受耕地生产环境和耕地系统弹性影响。研究结论:耕地健康产能评价指标体系和评价方法有应用性。     

How will the Belt and Road initiative advance China’s exports?

We examined 2007, 2010, 2012, 2014, and 2016 data from 49 countries to determine changes wrought by China’s Belt and Road initiative; we also used panel data regarding the Maritime Silk and Inland Silk Roads to test initiative effects on Chinese exports. Post-initiative infrastructure expansion and logistics performance improvements led to positive effects on China’s exports. Additionally, legal-system similarities and inland borders with trade partners had a more positive effect on Chinese exports in the Inland Silk Road, while population and free trade agreements were found to have a more positive effect on the Maritime Silk Road.     

成渝经济区生态农业对区域经济影响分析

[目的]区域经济发展反映经济各个方面的综合发展状况,探讨其影响因素以确定区域未来经济的发展方向,为进一步规划发展提供科学依据。[方法]先构建生态农业评价指标体系再采用层析分析法确定权重,结合线性加权和函数计算生态农业评价指数,通过相关分析法分析生态农业各个指标与区域经济的关系,最终确定生态农业对成渝经济区经济的影响程度。[结果]生态农业指标中评价指数大于0.9是森林覆盖率,介于0.8~0.7的包括投入产出比、土地生产率、农业科技贡献率、万人拥有的科技人员、劳动生产率、化肥施用量。且生态农业中各个指标与GDP都正相关,其中森林覆盖率、人均收入增长率、农业科技贡献率和万人拥有的科技人员与GDP显著相关,对区域经济的影响最大。[结论]成渝经济区经济受生态农业的影响,进一步选取更多生态农业相关因素,对于全面促进区域经济持续发展具有十分的重要现实意义。     

Models of static and dynamic technical efficiency of municipal libraries in the Czech Republic

This article deals with the modelling of the static and dynamic technical efficiency under conditions of municipal libraries of municipalities with 1000–5000 inhabitants. The aim of this article is to determine the level of the technical efficiency and the factors that influence the results of modelling of the static and dynamic technical efficiency of 34 selected municipal libraries for the years of 2011 and 2015. The first model tests the technical efficiency of conventional services of public libraries. The second model tests the technical efficiency of municipal libraries’ operation. The third model tests the technical efficiency of the key revenues and expenditures. The results in the static models estimate the average technical efficiency of municipal libraries in the interval (0.691–0.759) for the input-oriented models, and in the interval (1.413–2.005) for the output-oriented models. In the dynamic models, the majority of municipal libraries in 2015 showed lower technical efficiency and productivity in comparison with the year of 2011. The factors influencing the level of efficiency and its course include the inputs and the outputs, and their combinations within individual models.     

Three decades of productivity change in French beef production: a Färe‐Primont index decomposition

The Färe‐Primont index is used to evaluate total factor productivity (TFP) change and its components for a sample of French suckler cow farms in grassland areas in 1985–2014. The results reveal an increase in TFP of 6.6 per cent over the whole observation period, with technological progress being the major source of productivity growth. Meanwhile, efficiency decreased. Farms experienced great technological progress from 1991 to 2000. From a methodological point of view, the comparison with results obtained with Malmquist indexes shows similar trends but different magnitudes, with the Malmquist index overestimating the TFP and technological changes compared to the Färe‐Primont index. In addition, the use of a sequential approach that restricts technological change to being positive or null allows for the precise calculation of technology changes, disregarding the effects of external conditions that are captured in efficiency changes. Finally, the estimation of full dimensional efficient facets (FDEFs) that guarantees the positivity of all shadow prices used to assess the mix efficiency component of TFP change is promising.     

基于SARIMA-SVR组合模型的 空气质量指数预测

空气质量指数(AQI)在波动中既具有整体的时间序列线性特征和明显的季节性波动周期,又具有多种因素影响的不确定性,为了提高AQI的预测精度,基于Ri386 3.3.3和Matlab R2014a两种编程软件,提出了一种同时具有线性和非线性的复合特征的时间序列预测模型——SARIMA-SVR组合模型。以太原市2014年1月—2019年7月的AQI月均值数据为基础,利用SARIMA时间序列模型进行线性预测,利用SVR模型对残差进行非线性预测,加和得到组合预测模型的预测结果,分析比较SARIMA,SVR和SARIMA-SVR这3种模型的预测结果和平均绝对百分比误差。结果表明,组合预测模型发挥了2种模型各自的优势,相较于单一预测模型的预测结果而言,其预测精度更高,稳定性更好。通过此模型得到的空气质量预测结果不仅可为人们的日常生活提供指导,而且可为大气污染的防治工作提供科学依据和借鉴意义。     

基于DEA模型的建筑业环境行为效率评价研究

对建筑企业进行环境行为效率评价是促进我国建筑行业健康可持续发展的重要手段。根据建筑行业特点及我国现有的企业环境信用标准,构建了建筑企业环境行为评价的投入产出指标体系,将改进的数据包络分析方法模型运用到企业环境行为效率评价领域,解决了现有企业评价研究主观性突出的问题,得出建筑企业评价分析方法。在此基础上对某代表性建筑企业2010—2017年环境行为数据进行了评价分析。分析结果表明该企业环境行为总体效率良好,但鉴于出现了奇数年和偶数年的效率波动情况,仍需提高环境行为效率。     

On the Opportunity Cost of Crop Diversification

Distance functions are increasingly being augmented, with environmental goods treated as conventional outputs. A common approach to evaluate the opportunity cost of providing an environmental good is the exploitation of the distance function's dual relationship to the value function. This implies that the opportunity cost is assumed to be non‐negative. This approach also requires a convex technology set. Focusing on crop diversification for a balanced sample of 44 cereal farms in the East of England for the years 2007–2013, this paper develops a novel opportunity cost measure that does not depend on these strong assumptions. We find that the opportunity cost of crop diversification is negative for most farms.     

长江经济带中三角地区农业结构的分析与优化对策

[目的]从宏观、中观和微观3个层面深入分析长江经济带中三角地区湖北、湖南和江西3省的农业产业结构及其各产业差异性和相对优势及其竞争力。[方法]在宏观层面运用了传统的基尼系数分析3个省份历史发展上的地区经济水平差异,判断3个地区经济发展是否存在虹吸效应;从中观层面运用区位熵指数分析法分析区域农业产业结构,从农畜林渔等方面判断各区域产业专业化水平程度;从微观层面运用偏离—份额分析法(SSM)分离出3个地区的各部门产业的优势及其竞争力。[结果]区域内的经济差异变化呈不断增大的趋势,基尼系数不断扩大;湖北的种植业、渔业和农林牧渔服务业,湖南的种植业、林业、畜牧业和农林牧渔服务业,江西的林业、渔业都较中三角地区对应的子产业的区位熵指数高;江西木材和竹加工业和烟草业具有较大的产业竞争优势,湖北的茶叶、水产和瓜果疏菜产业优势明显,湖南地区农业产业综合优势主要在于烟草、水果、肉类以及木材和竹类加工业。[结论]通过比较地区农业产业竞争优势,提出发展地区产业特色,合理布局全域农业产业,提高农产品附加收益,稳固对结构优化的资金支持等对策建议。