贫困山区农户茶叶生产技术效率及影响因素研究

基于湖北省382份茶叶种植户调研数据,采用随机前沿生产函数模型“一步估计”法分析贫困山区农户茶叶生产技术效率和影响因素。研究结果表明:样本户茶叶种植存在较大改进空间;样本户资本和劳动力投入剩余;茶园的海拔、树龄、茶农是否加入合作社、种植面积、户主是否受过种茶培训等因素对农户茶叶生产技术效率有重要影响。因此,提出紧抓乡村振兴战略机遇,推动贫困山区茶产业高质量发展;建立茶产业“三项补贴”,改善茶园基础设施条件;优化茶叶种植布局,提高合作社服务水平;成立茶产业发展基金,加快培育职业茶农,以提高贫困山区农户茶叶生产技术效率。     

论移动应用平台的运维运营及技术管控工作

电力企业在移动信息化技术方面也迈出了步伐,开展电力业务现场作业、物资与基建的现场作业、故障抢修等班组作业应用,本文主要讨论移动应用平台的运维和技术管控工作,为移动应用平台的建设和发展提供一种工作思路。     

A spatial autoregressive stochastic frontier model for panel data incorporating a model of technical inefficiency

By integrating Battese and Coelli’s (1995) model and the spatial autoregressive model (SAR), a spatial autoregressive stochastic frontier model for panel data is developed. The main feature of this frontier model is a spatial lag term of explained variables and the joint structure of a production possibility frontier with a model of technical inefficiency. The model addresses both spatial dependence and heteroskedastic technical inefficiency. This study applies maximum likelihood methods considering the endogenous spatial lag term. The proposed model nests several existing models. Further, an empirical analysis using data on the Japanese manufacturing industry is conducted and the existing models are tested against the proposed model, which is found to be statistically supported. The findings suggest that estimates in the existing spatial and non-spatial models may exhibit bias because of lack of determinants of technical inefficiency, as well as a spatial lag. This bias also affects the technical efficiency score and its ranking.     

The impact of maize price shocks on household food security: Panel evidence from Tanzania

Using three waves (2008/09, 2010/11, 2012/13) of the Tanzanian National Panel Survey, this study investigates the impact of maize price shocks on household food security. Between 2008/09 and 2012/13, calorie intake stagnated for urban households, yet sharply deteriorated for rural households. The latter was driven by a significant decline in the consumption of the major staple maize which showed strongest price hikes among all major food items. Fixed-effects regressions indicate a clear negative relationship between maize prices and average household energy intake. Almost all population groups were found to be negatively affected by maize price shocks, with rural landless households being the most vulnerable group. In particular, a 50 percent rise in maize prices decreases caloric intake for rural (urban) households on average by 4.4 (5.4) percent, and for rural landless households by 12.6 percent. Results further indicate that subsistence agriculture can act as an effective strategy to insure against food price volatility.     

土地细碎化和土地质量是否影响小麦技术效率*——基于山东省小麦种植户的实证分析

［目的］小麦是我国重要的口粮之一，提高小麦的技术效率对于保障粮食安全具有重要的战略意义。在测算小麦技术效率的基础上，找出影响小麦技术效率的关键因素，为保障国家口粮安全提供参考。［方法］基于调研数据，运用超越对数生产函数以及一步随机前沿分析方法，构建计量模型分析土地细碎化和土地质量对小麦技术效率的影响。［结果］全部样本的技术效率差距较大，规模经营农户的技术效率高于小农户，农户技术效率最高的种植面积为67~333hm2，代表小麦种植的适宜规模。从技术效率的影响因素来看，土地细碎化程度和土地质量都对小麦生产的技术效率产生显著影响。［结论］为了提高小麦的技术效率，应该发展多种形式适度规模经营，鼓励创新土地流转形式，提高农业机械化水平； 深入开展土地质量调查，因地制宜地选择土地修复路径； 实行精准补贴，切实保护农民的利益。     

The intertemporal risk-Return relation,investor behavior,and technical trading profits: evidence from the G-7 countries

The intertemporal risk-return relation and investor behavior are both important pricing factors that jointly determine the expected market risk premium. Using the price adjustment process as a control variable, we find that the intertemporal risk-return relation is positive conditional on bad market news, but is non-positive conditional on good market news. This implies that good (bad) market news weakens (strengthens) the positive risk-return relation. The pattern in the distortion of the risk-return relation is consistent with short-term mispricing in which investors overvalue (undervalue) the stock market in reaction to good (bad) market news. We also show that ignoring the price adjustment process in the estimation of the risk-return relation leads to model misspecification and induces an upward (downward) bias in estimates of the relative risk aversion parameter conditional on good (bad) news. Our model of the asymmetric risk-return relation along with the price adjustment process is capable of generating the return dynamics that is attributable to technical trading profits. We suggest that the profitability of technical trading rules is not a violation of market efficiency, but a consequence of trading rules exploiting the asymmetric effect of price changes on the risk-return relation, along with the persistence property of price changes.     

Sources of fluctuations in hours worked for Canada,Germany, Japan and the U.S.: a sign restriction VAR approach

This study empirically examines the sources of fluctuations in hours worked in Canada, Germany, Japan and the U.S. It is particularly motivated by Galí’s (1999) VAR study, which demonstrates that a positive technology shock reduces hours worked, at least in the short run. However, in the present study, a technology shock is identified without recourse to Galí’s long-run restriction, which has been subject to active controversy. Furthermore, this study uncovers other important sources of fluctuations in hours worked to reflect the concern, raised by numerous studies, that technology shocks leave most variations in hours worked unexplained. Specifically, there are six shocks underlying our model, and they are identified using a set of sign restrictions. The empirical results confirm that in all four countries, a positive technology shock significantly reduces hours worked. This technology shock, along with labor supply and demand shocks, accounts for most of the short-term variations in hours worked. As the forecasting horizon increases, technology and demand shocks become less important, whereas labor supply shocks contribute to explaining the bulk of long-run variations in hours worked. Finally, the empirical relevance of Galí’s long-run identification restriction is tested and the results are related to those obtained using the sign restriction model.     

要素结构与技术进步方向——来自中国城市“撤县设区”的证据

本文基于1997—2010年267个地级及以上城市市辖区面板数据，运用标准化供给面系统方法测算了市级层面的技术进步方向，并借助“撤县设区”这一自然实验，利用工具变量法实证检验了要素结构变动对技术进步方向的影响，研究发现：（1)“撤县设区”使得资本—劳动比上升，进而导致技术进步方向偏向于资本，符合偏向型技术进步的“弱诱导偏向型假说”；（2)“撤县设区”对资本偏向型技术进步的影响是有条件的，主要限于资本—劳动替代弹性大于1即资本—劳动呈替代关系的地区；（3)相比于中西部地区，东部地区资本要素更为丰富，因而“撤县设区”显著提高了东部地区的资本—劳动比，使其技术进步方向偏向资本。     

Noise traders,firm-specific uncertainty and technical trading effectiveness

This is the first study to document evidence of technical trading effectiveness at firm level in the Chinese A-share market by investigating the relationship between excess profits of technical trading rules and firm-specific characteristics. Our results reveal that firms with higher excess profits from technical trading have more noise traders and higher institutional ownership and that those firms tend to be growth firms with lower liquidity and higher firm-specific uncertainty. Further analysis shows that the profitability of technical trading rules is unsustainable and the excess profits of the highest technical trading profit quintile portfolio disappear in the following year.