Evaluating the impact of land fragmentation on the cost of agricultural operation in the southwest mountainous areas of China

Given the background of the increasing opportunity cost of farming and the popularization of labour-saving technology, increased fragmentation has gradually become a key factor in the devaluation and abandonment of land assets. To systematically identify the costs of fragmentation, we use a series of indicators such as the number of plots, the Simpson index, the plot-homestead distance and the total minimum commuting time from the homestead to all plots to measure the extent of fragmentation. A translogcost function is developed and estimated using survey data from three periods, 2011, 2014 and 2017; the data include an effective sample of 1064 household-year observations involving 6599 plot-year observations in Chongqing, China. The extent of fragmentation in the mountains of southwest China is quite serious compared with that in other countries and regions. The Simpson index is 0.63, and on average, 6.06 mu (1 mu = 666.67 m² or 1 mu = 1/15 ha) of cultivated land is distributed in 6.16 plots, while the total minimum commuting time from the homestead to all plots is approximately 45 min. An increase of one standard deviation in the number of plots, the Simpson index or total minimum commuting time would lead to cost increases of 7.1 %, 15.1 % and 12.2 %, respectively, if other conditions remain unchanged. The channel for the above result involves the changes in the cost share of inputs caused by fragmentation, which increase the labour cost share and reduce the machinery cost share. There is an inverted U-shaped relationship between farm scale and production cost with an inflection point at 47 mu; that is, costs begin to decrease when the scale exceeds 47 mu. However, the average farm scale is currently only 6.06 mu. In addition, production costs can be significantly reduced by renting-in land and implementing land consolidation. To reduce land system-induced costs in mountainous areas, the government should rationally consolidate land to achieve moderate-scale management, reduce the transaction costs of land transfers and popularize machinery suitable for complex terrain.     

Operational efficiency analysis of Beijing multi-airport terminal airspace

Multi-airport systems are growing in number and size globally, despite being afflicted by known inefficiencies due to the interferences between the flows of neighbouring airports. A macroscopic empirical approach is proposed in this paper to estimate the capacity penalties and demonstrated by a numerical case study for Beijing, which is projected to become one of the busiest metroplexes in Asia. The Pareto envelopes of the theoretical and observed peak hour capacities are statistically analysed to quantify the penalties in a comparable metroplex and are subsequently modulated by a sigmoid correlation function. The analysis predicts the practical capacity of Daxing, the penalty incurred by the pre-existing Capital airport and by the total multi-airport system. Various findings are drawn and discussed, highlighting the needs for further research.     

国有林场贫困测定与差异性研究

基于2008—2017年国家林业局对中国28个省(市、区)国有林场的调研数据,运用等价性检验的方法从地理位置、经济状况、可持续经营和发展能力层面上对国有林场的贫困测度和差异性进行实证分析。研究结果表明:国有贫困林场不一定位于贫困县,并且与国有非贫困林场之间的差异逐渐缩小;国有贫困林场区域异质性强,经济发展水平较低;国有贫困林场在森林资源基础、人力资源基础、基础设施和生产条件等方面的可持续发展能力较差。因此,提出了相关林业部门应该鼓励国有贫困林场发展特色林产品;加大扶贫资金投入;改善职工生计条件;加强资金管理意识等政策建议。     

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。     

黑龙江省生态足迹分析及ARIMA模型预测

为了解黑龙江省生态可持续发展问题,对黑龙江省生态足迹进行分析,并寻求动态预测结果。运用生态足迹模型对黑龙江省2000~2015年的人均生态足迹和生态承载力进行测算,在此基础上选用ARIMA模型,并结合使用Eviews软件对未来10年人均生态足迹和生态承载力进行预测。研究结果表明2000~2015年间黑龙江省人均生态足迹一直不断增加,人均生态承载力呈现波动缓慢上升的趋势,生态系统处于不安全状态;2016~2025年黑龙江省人均生态足迹仍然持续增大,虽然人均生态承载力也缓慢上升,但人均生态赤字仍然越来越大,黑龙江省生态安全面临巨大挑战。     

Excess capacity,production technology and technical inefficiency in hospitality sector

This article examines the effects of excess capacity on the production cost and technical inefficiency of hotels and restaurants in Norway. The dataset includes a daily unbalanced panel of 94 hotels and restaurants from 2003 to 2014. To accommodate inefficiency, we use an input distance function (IDF). Inefficiency in the IDF means that if inputs are overused by k% then production cost is also increased by k%. We also allow inefficiency to differ across locations and regions by using them as determinants. The results indicate that excess capacity considerably affects the cost and increases inefficiency. The marginal effect on cost increases with excess capacity, but the effect on inefficiency sets in when it exceeds 50 percent. Furthermore, we find less overuse of inputs by firms in small metro towns and the Northern region causing them to be more efficient [except for the Southern and Western regions] than their counterparts.     

Systemic financial risk early warning of financial market in China using Attention-LSTM model

We propose an Attention-LSTM neural network model to study the systemic risk early warning of China. Based on text mining, the network public opinion index is constructed and used as a training set to be incorporated into the early warning model to test the early warning effect. The results show that: (i) the network public opinion is the non-linear Granger causality of systemic risk. (ii) The Attention-LSTM neural network has strong generalization ability. Early warning effects have been significantly improved. (iii) Compared with the BP neural network model, the SVR model and the ARIMA model, the LSTM neural network early warning model has a higher accuracy rate, and its average prediction accuracy for systemic risk indicators has been improved over short, medium and long terms. When the attention mechanism is included in the LSTM, the Attention-LSTM neural network model is even more accurate in all the cases.     

组织间学习与绿色创新:绿色吸收能力的调节作用

尽管组织间学习已经获得较多关注,但鲜有研究探讨它对绿色创新的影响。从组织间关系和双元性理论视角,提出了组织间的纵向利用式学习和横向探索式学习,基于组织学习理论和吸收能力理论,探究了两种组织间学习方式与绿色创新的关系,并检验了绿色吸收能力的调节作用。基于203家中国制造企业的调查数据,实证结果表明:纵向利用式学习和横向探索式学习都能显著正向影响绿色创新;相比横向探索式学习,纵向利用式学习对绿色创新的影响作用更强。绿色吸收能力在横向探索式学习与绿色创新之间也起调节作用,但它并不调节纵向利用式学习与绿色创新的关系。研究提出了不同的组织间学习方法与绿色创新的关系,丰富并拓展了绿色创新的相关研究。     

广西农业生态脆弱性评价及区划研究

［目的］随着经济的快速发展，我国各地区都面临着不同程度的农业生态脆弱性，通过研究特殊地形和气候下的农业生态脆弱性，有助于为农业生态环境的综合治理提供参考。［方法］文章以广西为例，通过构建评价指标体系，采用层次分析法和熵权法确定综合权重，通过构建综合评价模型对广西农业生态脆弱性程度进行评价，利用ArcGIS对生态脆弱性进行分级，以期探究广西农业生态脆弱性的空间分布情况。［结果］权重分析结果表明水蚀面积的权重值最高为0134，年平均降水量的权重值为0113，自然环境指标相对于农业生产和经济指标对农业生态脆弱性的影响更大。区划研究结果表明广西农业生态脆弱性区域大致可分为5个区域，分别是桂西峰丛洼地带、桂东山地丘陵地带、桂中低山丘陵地带、桂东北山地、桂南沿海丘陵地带。［结论］广西农业生态环境整体来看较为脆弱，处于轻度和中度脆弱等级，但生态环境问题仍不容忽视。为了改善农业生态脆弱性，政府应实行区域的联合防治，加大对农业生态环境的监督和治理，积极探寻生态、环保的农业发展方式，调整产业结构，改善农业生态环境的状态，促进广西农业的可持续发展。