农户行为对农牧民收入影响初探--以西藏改则县为例

运用实地抽样调查数据,初步探讨改则县的农户行为与牧民收入的关系,分析了城郊改则镇牧民收入低于其它乡这一现象的主要原因：①由于区位优势,牧民试图寻求增收的捷径,而不安分于畜牧业的生产,导致草地的低效利用;②第三产业没有真正发展起来,发展导向没有与畜牧业相结合,而且由于缺乏管理技术和经验,第三产业的投入／产出比高,所以少数从事第三产业的农户并没有因此而提高家庭收入水平;③地处青藏高原,外出打工交通成本高,加上浓厚本土意识,牧民不愿意到外省打工,而本区就业机会少,劳动力廉价,所以劳务输出并没有成为牧民增收的有效途径;④牧民文化水平低,缺乏科学的生产技术,导致生产投入的利用效率低。     

基于ESDA-GWR的粮食单产及其驱动因子的空间异质性研究

在耕地面积扩展有限和城市化高速发展的背景下,粮食单产的区域差异对我国粮食安全具有重要意义。以我国31省（市、自治区）为研究单元,借助ESDA和GWR模型,结合我国各地自然条件的差异及其经济发展类型,揭示我国粮食单产的区域差异及其驱动因子的空间异质性。结果表明：1999—2008年,中西部地区粮食单产的增产对全国粮食产量的贡献越来越显著,75%的粮食单产增长潜力较大的区域集中在中西部;粮食单产存在着显著的空间相关性,各省域粮食生产重心发生移动,由传统的＂东部为主＂逐渐＂北上西进＂,向中西部地区欠发达省份集中;不同区域粮食单产的驱动因素呈现为一种非均衡联动的局域性特征,化肥施用量对粮食单产的影响在两个时间断面中差异最大,1999年回归系数全为正值,而在2006—2008年出现负值,这表明部分地区化肥对粮食单产的边际效应已经达到递减阶段。因此,应结合我国不同区域当前粮食单产的现状和驱动因子的效应机理,积极采取相应的有效措施以保障我国的粮食安全。     

Optimum government size and economic growth in case of Indian states: Evidence from panel threshold model

This paper investigates the relationship between optimum government size and economic growth using data of Indian states during 1990-91 to 2017–18. Our results derived from panel threshold regression model show a positive and significant impact of government size on economic growth within the estimated thresholds for both aggregate and sub-panels based on income and regions. Once the government size moves above the upper threshold level, then its impact declines and turns to be insignificant. Thus, our findings suggest the policymakers for maintaining the government size within the thresholds limit.     

Value for money in energy efficiency retrofits in Ireland: grant provider and grant recipients

The Sustainable Energy Authority of Ireland (SEAI) administers the Better Energy Homes scheme to provide a financial incentive for home owners to engage in energy efficiency retrofits. This study analyses data from the scheme and Building Energy Rating data for participants to the scheme to examine the value for money achieved by households. In addition, this research identifies which retrofit combinations provide greatest value for money, in terms of energy efficiency gains, for the grant provider. We utilize an error-in-variables approach to model the variation in benefits accruing to households of varying characteristics. We find that household and grant provider surplus can be maximized in the short term by retrofitting less energy efficient and larger homes, timber or steel frame homes and houses rather and apartments. The types of retrofits leading to the greatest surplus for both household and grant provider include cavity wall insulation paired with either a boiler with heating controls or heating controls only retrofit.     

Stock Price Index and Exchange Rate Nexus in African Markets

This paper examines the relationship between stock price index and exchange rate in six African markets using monthly data for the period January 2007 to October 2015. A quantile regression approach is used. This methodology is shown to perform better than the ordinary least squares estimators, particularly when the conditional distribution is heterogeneous. Our empirical evidence reveals an interesting pattern in the association of these two financial markets in Africa, which shows that the negative relationship between stock and foreign exchange markets is more apparent when exchange rates are extremely low or high. The negative relationship between the two variables is in line with the portfolio balance effect.     

Assessment of the effect of the financial crisis on agents’ expectations through symbolic regression

Agents’ perceptions on the state of the economy can be affected during economic crises. Tendency surveys are the main source of agents’ expectations. The main objective of this study is to assess the impact of the 2008 financial crisis on agents’ expectations. With this aim, we evaluate the capacity of survey-based expectations to anticipate economic growth in the United States, Japan, Germany and the United Kingdom. We propose a symbolic regression (SR) via genetic programming approach to derive mathematical functional forms that link survey-based expectations to GDP growth. By combining the main SR-generated indicators, we generate estimates of the evolution of GDP. Finally, we analyse the effect of the crisis on the formation of expectations, and we find an improvement in the capacity of agents’ expectations to anticipate economic growth after the crisis in all countries except Germany.     

老年人旅游消费影响因素的实证研究——以洪山区为例

通常的研究认为,消费与收入有关,旅游消费也不例外。对洪山区老年旅游者进行问卷调查和实证分析,得到如下结论：影响老年人旅游消费的主要因素是个人旅游偏好和空余时间的安排;同时,老年人大都关注体力和健康因素,而对花费和经济因素则一般不太关注。最后,基于实证研究的结论对如何提高中国老年人旅游需求提出了增强旅游资源的宣传发展特色旅游、加大政府投入,完善基础设施,提高服务水平等建议。     

Mean squared error of the empirical best linear unbiased predictor in an orthogonal finite discrete spectrum linear regression model

The mean squared error (MSE) of the empirical best linear unbiased predictor in an orthogonal finite discrete spectrum linear regression model is derived and a comparison with the MSE of the best linear unbiased predictor in this model is made. It is shown that under weak conditions these two mean square errors are asymptotically the same.     

On Minimally-supported <Emphasis Type="Italic">D</Emphasis>-optimal Designs for Polynomial Regression with Log-concave Weight Function

This paper studies minimally-supported D-optimal designs for polynomial regression model with logarithmically concave (log-concave) weight functions. Many commonly used weight functions in the design literature are log-concave. For example, and exp(−x ²) in Theorem 2.3.2 of Fedorov (Theory of optimal experiments, 1972) are all log-concave. We show that the determinant of information matrix of minimally-supported design is a log-concave function of ordered support points and the D-optimal design is unique. Therefore, the numerically D-optimal designs can be constructed efficiently by cyclic exchange algorithm.     

创新驱动下中国区域高质量发展——基于平衡充分发展水平的门槛分析

创新驱动是破解中国区域不平衡不充分发展的突破口,是实现高质量发展的助推器。采用2003—2017年中国30个省市(因数据缺失,不包括西藏地区和港澳台地区)面板数据,运用全局参比Malmquist模型测度了中国区域高质量发展水平,并通过构建指标体系分别对中国各省市的平衡发展和充分发展水平进行了评价,然后通过门槛回归模型分析了在不同平衡和充分发展水平下创新驱动对于高质量发展的影响机制。结果发现:①区域高质量发展水平呈现出先下降后上升的变化趋势;②各省市平衡和充分发展水平均呈现上升趋势,但各省市之间的变化情况差异较大,有明显的空间集聚特征;③在不同的平衡及充分发展水平下,创新驱动对高质量发展的影响机制是不同的,当平衡充分发展水平较低时,创新驱动对高质量发展没有显著影响;当平衡充分发展达到一定水平时,创新驱动对高质量发展起到一定的促进作用;随着平衡充分发展水平的进一步提高,创新驱动对高质量发展的促进作用越来越大。