长江经济带农业绿色生产效率及其时空分异特征研究

［目的］从静态分析和动态分析两个方面，阐释长江经济带农业绿色生产效率和农业绿色全要素生产率的时空分异特征以及生产率增长来源，以期为提高长江经济带农业绿色发展质量提供科学决策依据。［方法］文章基于资源环境约束的角度，利用MinDS模型和Global Malmquist Luenberger指数相结合的方法，测算长江经济带农业绿色生产效率和农业绿色全要素生产率，并将农业全要素生产率变化分解为纯技术效率变化（PEC）、纯技术变化（PTC）、规模效率变化（SEEC）和规模技术变化（SETC）4个部分。［结果］（1）长江经济带农业绿色生产效率水平较高，且呈不断增长趋势，下游地区的农业绿色生产效率高于中、上游，且中、上游与下游地区的差距不断拉大； （2）长江经济带农业绿色全要素生产率增长较快，以3年为1个周期，呈现波动式上升趋势，其增长主要源于纯技术进步和规模技术提高； （3）长江经济带下游农业绿色全要素生产率增长率最高，上游次之，中游最低，其中，下游农业绿色全要素生产率增长主要源于纯技术进步，中游是纯技术效率改进、纯技术进步和规模技术提高共同作用的结果，上游则源于纯技术效率改进、纯技术进步和规模效率提高。［结论］长江经济带上、中、下游三大区域的农业绿色发展水平和发展能力存在较大差异，需制定差异化政策，以调整农业增长模式，促进农业转型升级，实现高质量发展。     

我国蛋鸡养殖环境全要素生产率测度及省域比较分析

［目的］蛋鸡养殖场规模化养殖与生态环境保护协调发展问题是蛋鸡养殖业可持续发展过程中面临的关键性问题，测度我国大、中、小3种规模下不同省份蛋鸡养殖场的环境全要素生产率，并从时间、地区两个维度对蛋鸡养殖场的环境全要素生产率进行比较。［方法］利用2004—2016年不同养殖规模蛋鸡养殖场的投入和产出数据，文章基于SBM函数的Malmquist Luengerber（ML）指数方法，对蛋鸡养殖场环境全要素生产率进行分解，将其分解为技术进步指数、效率改进指数。［结果］（1）蛋鸡养殖场环境全要素生产率整体呈现下降趋势，同时与蛋鸡养殖规模呈反比，蛋鸡养殖场规模越大，蛋鸡养殖环境生产率越小。（2）蛋鸡养殖场效率存在效率改善，但养殖技术进步率相对较低，尤其是对小规模养殖场而言，改善空间更明显； （3）蛋鸡养殖环境全要素生产率区域差异较为明显，整体来看，蛋鸡养殖主产区环境全要素生产率高于非主产区。［结论］加强蛋鸡产业科技创新水平以及公共服务设施的投入，提高养殖户的废弃物无害化处理能力，推行蛋鸡养殖的规模化和标准化发展，进一步改善养殖效率，以促进蛋鸡养殖规模化和生态环境保护协调发展。     

Efficiency drivers of international airports: A worldwide benchmarking study

The main purpose of these work was to identify operational efficiency drivers of international airports. In order to achieve this, a two-step quantitative-qualitative research approach was conducted. In the first step, a two-stage DEA model was used, and it was possible to identify, within a sample of the 60 biggest airports from the six Airport Council International (ACI) regions, the most efficient airports of the world: Beijing International Airport, Heathrow International Airport, Dubai International Airport, and Hartsfield-Jackson Atlanta International Airport. In the second step of the research, four airports were selected in order to search for the efficiency drivers. In this context, Heathrow International Airport was considered to be a benchmark and presented most of the identified efficiency drivers (27 of 31). Standing out were Just-in-Time (JIT) and Total Quality Management (TQM) principles and also Passenger boarding optimization, besides the presence of almost all of the most relevant efficiency drivers, according to airport managers.     

中美玉米期货市场功能效率比较

价格发现与套期保值是期货市场的基本功能,能够反映期货市场的运行效率。通过对比中美贸易摩擦前后期货市场的价格发现和套期保值功能,分析中美玉米期货市场效率间的差距,探究我国玉米期货市场运行效率低的原因。利用格兰杰(Granger)因果分析、协整检验、分位信息份额模型、套期保值比率及绩效分析方法,定量对中美两国2013—2019年玉米期货及现货的数据进行分析,结果表明,中国玉米期货市场存在较强的价格发现功能,但套期保值绩效不佳。使用前沿分位信息份额模型和滚动格兰杰因果法分析中美两国期现货市场动态关系的区别,发现中国仅存期货市场对现货市场的单向引导,而美国在中美贸易摩擦前表现为玉米期现货市场具有相近的引导能力,套期保值效率较高,中美贸易摩擦增强了其现货市场对期货市场的引导能力,降低了期货市场运行效率。从期现货市场双向引导关系视角来看,中国玉米期货市场效率低的原因主要是现货市场的信息不完全、发展不完善,期现货市场缺少长期稳定的双向引导关系抑制了期货市场功能发挥。中国应全面加强期货市场建设,提升期货市场定价效率,推动农产品期货市场快速健康发展。     

Economics of household food waste

Food waste has drawn increasing public attention, and the high levels of estimated waste are largely considered to be a failure of our current food system. Recently, economists have begun to weigh in, showing food waste can emerge as the result of a complex equilibrium affected by consumers’ preferences for convenience; expectations about future food prices and availability; food safety concerns; producers’ costs of holding inventory, transportation, and storage; government regulation; and technology. If food waste is a form of inefficiency, there are either strong economic motivations to reduce waste, or unmeasured costs or preferences affecting waste decisions. If consumers have behavioral biases, suffer from information asymmetries, or do not pay the full cost of their waste, there may be a role for government intervention to reduce waste, but most empirical models in the literature have not articulated or quantified the extent of the deadweight loss from the market failures in relation to food waste. In some cases, waste reduction efforts could harm producers if overall demand for food is reduced or harm consumers if overconsumption is encouraged, quality or safety degrades, or supply disruptions occur. Technological innovations, which lower the cost of storage or extend shelf life have the potential to improve both consumer and producer welfare.     

云南省农业科技创新资源配置效率及影响因素研究

[目的]为及时了解云南省农业科技创新的最新动态,充分合理地开发云南省农业科技资源,文章对2002—2016年云南省的农业科技创新资源配置进行研究。[方法]首先分析各个单项指标15年内的变化趋势,分析其对资源配置的影响和作用。再运用DEA模型分析法,将2002—2016年的每个年份作为一个决策单元进行处理,对云南省农业科技创新资源配置效率进行分析。[结果] 2002—2016年云南省农业科技创新资源配置的综合效率为0. 984,并且呈现出不稳定的波动,在2004和2009—2012年出现了配置效率降低的情况。总体来看,资源配置的综合效率大体上是接近于1的水平。处于DEA有效的年份为2002—2003年,2005—2008及2013—2016,属于规模报酬不变的阶段; 2004年属于弱DEA有效阶段,规模报酬则处于上升阶段;处于非DEA有效的有2004年、2009—2012年。[结论]云南省农业科技创新资源的配置效率整体水平处于较高的状态,综合效率值总体上接近于1。有个别年份出现了较小范围的波动,可能与总播种面积的变化有关。综合来看,云南省农业科技创新资源在技术投入、人力资源和农业资金投入逐年的增加,使资源配置效率能够保持在较高的水平,并在出现下降后迅速恢复。     

毛竹水溶性多糖提取工艺的优化及结构表征

采用响应面法优化毛竹水溶性多糖的提取工艺,分析其成分,并进行结构表征。研究结果表明,优化的毛竹多糖(BSP)提取条件为:料液比1∶27(g/mL)、提取温度78 ℃、提取时间4 h,该条件下BSP提取率为(5.18±0.07)%,提取物中多糖含量为(72.14±0.02)%,糖醛酸含量为(9.76±0.03)%;BSP具有酸性多糖典型的官能团特征吸收峰,其单糖组成及摩尔比为n_甘露糖∶n_葡萄糖∶n_阿拉伯糖∶n_木糖∶n_鼠李糖∶n_半乳糖=62.52∶23.05∶10.35∶2.78∶0.79∶0.51;BSP由两个主峰组成,相对分子质量分别为91.11、4.55 kDa。BSP是一种混合酸性多糖。     

集中连片特困地区扶贫产业发展的规模特征及其经济效率评价——以武陵山片区恩施自治州为例

[目的]在扶贫开发战略中成长起来的特色产业已经成为贫困地区经济发展和农民脱贫致富的支柱产业,特色产业的规模和经济效率直接决定着贫困地区脱贫致富能力。[方法]文章以茶叶、蔬菜代表武陵山片区湖北省恩施自治州扶贫产业,利用集中度指数、扩张弹性系数、单位面积的产值能力和产量能力以及单位产量的产值能力等指标进行扶贫产业发展的规模特征及其经济效率评价。[结果]“十一五”期间以来武陵山片区扶贫产业发展的产业地位逐渐提高、规模扩张优势显著、规模收益递增、投入规模扩张率高于产出规模扩张率、资源配置效率不断提高,比较经济效率差距持续扩大。[结论]扶贫产业亟待根据产业发展的生态化、集聚化和融合化等趋势,在规模扩张中强化特色产品的品质建设和效率优势品种生产专业化程度、提高生产技术水平以及完善产业化组织及其能力建设,提高扶贫产业的经济效率和致富能力。     

Are betting returns a useful measure of accuracy in (sports) forecasting?

In an economic context, forecasting models are judged in terms not only of accuracy, but also of profitability. The present paper analyses the counterintuitive relationship between accuracy and profitability in probabilistic (sports) forecasts in relation to betting markets. By making use of theoretical considerations, a simulation model, and real-world datasets from three different sports, we demonstrate the possibility of systematically or randomly generating positive betting returns in the absence of a superior model accuracy. The results have methodological implications for sports forecasting and other domains related to betting markets. Betting returns should not be treated as a valid measure of model accuracy, even though they can be regarded as an adequate measure of profitability. Hence, an improved predictive performance might be achieved by carefully considering the roles of both accuracy and profitability when designing models, or, more specifically, when assessing the in-sample fit of data and evaluating out-of-sample forecasting performances.     

Credit risk pricing and the rationality of lending decision-making within dual banking systems: A parametric approach

The reduction of non-performing loans, and making correct provisions for them, plays a primary role in the management and minimization of banking credit risk. However, these actions depend primarily upon the cost at which banks may dispose of these bad loans. Hence, this study aims to perceive the price of banks’ credit risk via estimating the shadow price of non-performing loans. We assess and compare the perceived price of the credit risk of Islamic and conventional banks operating in 9 countries from the Middle East and Asia, using a quadratic directional distance function. Following this, we evaluate the impact of different settings of directional vectors on shadow prices by conducting a risk-sensitivity analysis. Applying bootstrap regression, the factors affecting NPLs’ prices are further investigated. The paper concludes that the estimation of the shadow prices of bad loans can provide important elements in favor of credit risk management and, therefore, credit risk mitigation.