《算学启蒙》中的香料经济新探

《算学启蒙》中有关香料方面的算题,涉及元代市舶司的“双抽”和“单抽”、纸钞与铜银钱并用,以及各种香料的价格等问题。诚然,这些问题的解决,确实需要综合多种史籍来参互求证,但毋庸置疑的是《算学启蒙》起到了为其他史籍所无法取代的独特价值和作用。实际上,元代大德年间所发生的许多经济现象,都或多或少在《算学启蒙》一书中有所体现。随着学界对中国古代算书之史学价值的认识愈来愈明确,经济数学、数学社会学等新的交叉学科应运而生,我们不能仅仅囿于从纯数学的角度去解读《算学启蒙》,因为《算学启蒙》本身具有更重要的经济史和社会史的研究价值和意义。     

Higher Intensity,Higher Profit? Empirical Evidence from Dairy Farming in New Zealand

Over the last two decades there have been significant and well‐documented changes in the nature and structure of New Zealand dairy production. One particular feature has been a marked shift in the ‘input intensity’ of dairy farming systems through increased use of supplementary feed. These changes have generated debate about the impact of dairy farm intensity on the performance of farm businesses and the competitiveness of the New Zealand dairy sector. Using a novel econometric approach, we assess statistically the impact of three types of dairy farming systems on milk production and financial performance, using farm business data provided by DairyBase^®. Our empirical results show that higher input systems perform significantly better physically than lower input systems, but not financially. The disaggregated analysis suggests that the average treatment effects differ by region and performance quantiles.     

内外融资条件、融资约束与企业绩效——来自京津冀地区企业调查的新证据*

基于独特的京津冀地区企业调查数据和克服内生性的结构方程模型，本文对融资约束的成因及影响进行了实证分析。分析结果表明，企业自身条件和外部市场环境均对融资约束有重要影响，且企业自身条件对融资约束的影响更强。总的融资约束指标对企业绩效的影响不显著。在区分融资约束的不同维度后，本文发现，融资可得性提高显著促进了企业绩效提升，融资频率增加却降低了企业绩效，而融资获得速度（等待时间）对企业绩效没有统计上的显著影响。进一步的分析表明，无论是正规融资渠道，还是非正规融资渠道，上述结论仍然成立。利用多种政策提高企业的管理水平，改善企业的自身条件，是缓解融资约束的最有效办法。     

Volatility forecasting: long memory,regime switching and heteroscedasticity

In this article, we account for the first time for long memory, regime switching and the conditional time-varying volatility of volatility (heteroscedasticity) to model and forecast market volatility using the heterogeneous autoregressive model of realized volatility (HAR-RV) and its extensions. We present several interesting and notable findings. First, existing models exhibit significant nonlinearity and clustering, which provide empirical evidence on the benefit of introducing regime switching and heteroscedasticity. Second, out-of-sample results indicate that combining regime switching and heteroscedasticity can substantially improve predictive power from a statistical viewpoint. More specifically, our proposed models generally exhibit higher forecasting accuracy. Third, these results are widely consistent across a variety of robustness tests such as different forecasting windows, forecasting models, realized measures, and stock markets. Consequently, this study sheds new light on forecasting future volatility.     

苹果种植适度规模经营研究*——以陕西省白水县为例

［目的］分析苹果种植户经济效益的影响因素，研究适合苹果种植的农地规模，提高白水县果农苹果种植的经济效益，探索苹果产业可持续发展经营模式，丰富以果蔬为主的集约型经济作物适度规模经营研究范围。［方法］采用实地调研法，对陕西省白水县230户苹果种植户进行问卷调查，从收益最大化角度，运用柯布道格拉斯生产函数对苹果生产的投入产出进行经济分析，构建收益最大化模型，测算白水县苹果种植的最适规模，分析苹果产量的影响因素，探讨劳动力投入、资本投入、有效面积和果农参加技术培训对苹果产出的影响和贡献程度，并用钱克明等对农地的适度经营规模定义进行结果验证，最后提出合理的政策建议。［结果］经过分析，在同等技术条件下，劳动力投入、资本投入、有效种植面积、果农参加技术培训的次数对苹果的产出具有显著影响。以农户收益最大化模型测算的劳均经营规模面积在0363~0447hm2（544~670亩）的可视为适度规模，根据钱克明等的适度经营规模目标值的计算，其函数解为550，在适度规模范围之内。即户均农地适度经营规模0751~0966hm2（1127~1449亩）。目前白水县苹果生产处于规模报酬递减阶段，农资市场环境和劳动力投入方面仍然存在短板。［结论］建议扩大白水县户均苹果种植面积，提升土地经营效益，从而增加果农收入，支持农业新型经营主体发展，创新发展模式； 建立新型职业农民培育体系，促进苹果种植户剩余劳动力转移，提高农民非农收入； 从法律上规范农村地区农资市场环境； 规范农户绿色生产经营行为，提高化肥的使用效率和开发新的高效肥料； 政府引导农地的适度规模集中，整合资源进行规模化、现代化的经营。     

Agency costs and tax planning when the government is a major Shareholder

In state owned enterprises (SOEs), taxes are a dividend to the controlling shareholder, the state, but a cost to other shareholders. We examine publicly traded firms in China and find significantly lower tax avoidance by SOEs relative to non-SOEs. The differences are pronounced for locally versus centrally-owned SOEs and during the year of SOE term performance evaluations. We link our results to managerial incentives through promotion tests, finding that higher SOE tax rates are associated with higher promotion frequencies of SOE managers. Our results suggest managerial incentives and tax reporting are conditional on the ownership structure of the firm.     

多视角县级空间开发适宜性评价方法对比研究

［目的］随着市县经济社会发展总体规划的改革创新，越发强调主体功能区制度的完善、强化政府空间管控的能力。空间开发适宜性是合理划分国土空间、优化开发布局的重要基础。［方法］研究通过选取了地形地势、交通干线、人口聚集度、经济发展4项适宜性指标和自然灾害影响、可利用土地资源、可利用水资源、生态系统脆弱性4项约束性指标，建立空间开发适宜性评价指标体系，分别从格网与行政区两种视角出发，开展蒲江县级空间开发适宜性评价，采用点对点匹配度分析对两种评价结果进行综合对比分析。［结果］从总体看，蒲江县最适宜区域占比约为4%，较适宜区域占比约为14%，较不适宜区域占比约为15%，最不适宜区域占比约为67%。行政区视角下，各类开发适宜性等级区域差异明显，但街道、乡（镇）行政区内部具有均质性。具体来说，各类开发适宜性等级区有按行政区集聚的趋势，并且其集聚趋势与多指标评价结果关系密切。空间视角下，各类开发适宜性等级跨行政区，街道、乡（镇）行政区内部具有异质性。一方面，各类开发适宜性等级不受行政区影响，局部精准性更高。另一方面，形成跨行政区的开发时序判读，并且这种开发时序多呈现“中心—外围”结构，便于具体指导区域分步开发。［结论］格网尺度可以更精细地反映县级开发适宜性和开发约束性在空间上的差异化分布，提高城镇、农业、生态3类空间范围划定精准性，为合理确定资源开发强度、促进国土空间科学适度有序布局提供技术保障。     

互联网视角下供应链金融的新发展

在这个网络社会愈发深化的时代,通过互联网科技完善和发展线上供应链金融成为必要的发展方向。本文首先梳理了传统供应链金融的基本模式,发现了其存在的不足;然后重点介绍了当前三种主要的线上供应链金融模式,总结了线上供应链金融的优势;最后,提出相关政策建议,认为金融机构应该不断升级线上供应链金融产品,逐步完善供应链金融线上操作系统,监管机构需要出台更加严格的监管规则对线上供应链金融进行有效监管。     

The Impact of Farmland Transfers on Agricultural Investment in China: A Perspective of Transaction Cost Economics

There is growing concern that farmland transfers lead to less agricultural investment, which may adversely affect agricultural productivity growth in China. Prior research has primarily focused on the differences between owned cultivated land and rented plots, but little is known about how farmland transfers between relatives, which are popular in rural China, specifically affect agricultural investment. In this paper, we present a conceptual framework of transaction cost economics to compare different contracting strategies in China's farmland rental markets. As farmland rental markets in China are immature, land transfer between relatives establishes bilateral governance, which has the advantage of addressing the opportunistic activities of both parties and can ultimately increase investment by tenants. Based on data from two waves of household surveys, we empirically examine the impact of bilateral governance on the application of organic fertilizer, an indicator for agricultural investment. Our findings show that apart from economic factors, kinship is important to the functioning of farmland rental markets in rural areas.     

智能制造有利于增加企业技术创新投入吗——基于智能制造试点的准自然实验

智能制造是我国制造业转型升级的主攻方向,而如何准确客观评价智能制造的实施效果成为亟待解决的问题.从技术创新投入视角,将智能制造试点政策实施视为一次准自然实验,采用2011-2019年制造业上市企业面板数据,通过PSM-DID方法研究智能制造对企业技术创新投入的影响.研究结果表明,智能制造显著影响企业技术创新投入,即通过提升客户集成度、供应商集成度进而提高企业技术创新投入,且促进作用仅发生在民营企业和非高新技术行业中.该发现扩展了现有研究外延,同时,为解决当前国际困局和促进智能制造的持续推广提供了重要实践价值.