认购权证与标的股票间的价格相关关系实证研究

为系统分析我国认购权证市场与其标的股票市场间的价格相关关系，发现权证市场与股票市场间的联系。本文以12组样本认购权证目收盘价和标的股票的目收盘价为观测对象，运用ADF单位根检验、Johansen协整检验、向量误差修正模型（VECM）、Granger因果检验和Hasbrouck方差分解方法，考察了两个时序数列间的长期均衡关系、短期动态关系、Granger因果关系和两市在价格发现功能中作用的大小、反映信息的效率，得出了研究结论。     

Do Vietnamese upland farmers benefit from high world market prices for maize?

For rural households in the north of Vietnam, maize cropping is the main source of income. In the face of the world market price increases of the recent past, we analyze the regional marketing chain of this commodity qualitatively and econometrically investigating to what extent smallholder farmers in developing countries are affected by international price movements. Vietnamese maize markets are found to be well integrated. Recent price hikes have fully transmitted along the regional supply chain so that farmers profited. Nevertheless, adverse factors such as increasing input prices have neutralized these benefits resulting in a decline in real income of smallholders.     

新疆能源消费碳足迹变化、影响因素及其演进分析

经济增长对能源消费的依赖性与生态环境恶化的矛盾日趋严重。本文采用 IPCC 方法测算了新疆能源消费碳足迹,利用岭回归对扩展的 STIRPAT 模型进行拟合,分析了各因素对碳足迹影响的演进规律,结果表明：1990-2011年新疆能源消费碳足迹整体上呈上升趋势,年均增长率为5.82%,其中能源消费碳足迹的构成中以煤炭为主,石油次之,天然气最小;新疆能源消费碳足迹产值在绝对数值和增长率方面都处于较低的水平,能源利用效率还有待提高;新疆不存在环境库兹涅茨曲线;各驱动因素对碳足迹增长的贡献会随着时间推移发生变化,人均GDP 从2011年起已经成为对碳足迹影响最大的驱动力,而城镇化率对碳足迹的影响相对有限。     

侧向支承作用下简支钢梁整体稳定性研究

本文对简支工形钢梁受压翼缘有两道侧向支承时的整体稳定性能进行了系统研究。首先根据能量法原理,把中梁段单独取出来,推导了3种不同荷载类型作用下钢梁整体稳定临界弯矩;其次介绍了Nethercot和Trahair建议的考虑梁段相互约束效应的计算方法（简称“NT法”）。采用ANSYS有限元分析软件,对总跨度为15 m的简支钢梁,考虑其侧向支承条件、截面形式、荷载类型的变化,共计算了144根钢梁,对其进行了特征值屈曲分析。然后对3种方法计算的整体稳定临界荷载进行了对比分析,通过分析对比评价了两种理论方法的计算精度和实用性。最后根据有限元分析的结果,拟合了满跨均布荷载作用、跨中集中荷载作用、支承处集中荷载作用下钢梁等效弯矩系数的计算公式。     

Linear predictability vs. bull and bear market models in strategic asset allocation decisions: evidence from UK data

Most papers in the portfolio choice literature have examined linear predictability frameworks based on the idea that simple but flexible Vector Autoregressive (VAR) models can be expanded to produce portfolio allocations that hedge against the bull and bear dynamics typical of financial markets through careful selection of predictor variables that capture business cycles and market sentiment. Yet, a distinct literature exists that shows that non-linear econometric frameworks, such as Markov switching, are also natural tools to compute optimal portfolios arising from the existence of good and bad market states. This paper examines whether and how simple VARs can produce portfolio rules similar to those obtained under a simple Markov switching, by studying the effects of expanding both the order of the VAR and the number/selection of predictor variables included. In a typical stock-bond strategic asset allocation problem for UK data, we compute the out-of-sample certainty equivalent returns for a wide range of VARs and compare these measures of performance with those of non-linear models. We conclude that most VARs cannot produce portfolio rules, hedging demands or (net of transaction costs) out-of-sample performances that approximate those obtained from simple non-linear frameworks.     

Equilibria in infinite dimensional commodity spaces revisited

Summary. The aim of the paper is to provide a new proof of the Mas-Colell–Richard existence of equilibrium result when preferences are non-transitive and incomplete. Our proof generalizes the main ideas of the Negishi approach to the case of unordered preferences. Received: January 10, 1996; revised version: November 23, 1999     

Price relationships between qualitatively differentiated agricultural products: organic and conventional wheat in Germany

Organic agriculture, which produces commodities that can be qualitatively differentiated from conventional food products, has grown into an important market in many countries. The dynamics of commodity prices in both sectors are partly interdependent, but are also shaped by independent determinants and have rarely been studied. We analyze organic food markets and their interdependencies with conventional markets in the context of wheat markets in Germany, which have been subject to a number of fundamental changes during the last two decades. Based on institutional market characteristics, we suggest a flexible Markov‐switching asymmetric time series model. We find a pronounced temporal sequence of market phases that differ in their asymmetric dynamics and the extent to which the organic price is influenced by the conventional price. Organic wheat prices tend to be increasingly connected to prices of conventional wheat.     

混合地理加权回归模型的拟合及相关性检验

利用两步估计方法对混合地理加权回归模型进行拟合,运用Moran's检验方法探索误差项的空间相关性。     

东北地区农村宅基地闲置特征及影响因素研究——基于公主岭市6乡镇实地调研数据

[目的]通过实地调研和问卷调查收集农村宅基地闲置相关信息,分析农村宅基地闲置特征和影响因素,以期为乡村振兴过程中推动农村宅基地制度改革提供参考。[方法]描述性统计方法和Logistic二元回归模型。[结果]宅基地完全闲置率约为13.19%,季节性闲置率约为31.79%,宅基地季节性闲置较为严重;宅基地面积超标严重,存在内部闲置现象,庭院利用效率低下;闲置宅基地流转程度以及村集体对闲置宅基地的处置能力较低;户主年龄、人均耕地面积、家庭人均年收入、务工人数占比、宅基地数量和宅基地退出意愿影响宅基地的闲置,户主年龄、人均耕地面积和宅基地退出意愿对宅基地闲置产生负向影响,家庭人均年收入、务工人数占比和宅基地数量对宅基地闲置产生正向影响。[结论]针对宅基地闲置问题,必须在保障农民居住权之上,充分放活宅基地使用权,合理规划并管控宅基地规模,对于不同闲置类型的宅基地探索差异化解决途径,推动宅基地使用权自由流转、宅基地用途转换等,通过盘活宅基地助力乡村振兴。