最低收购价政策对小麦市场价格波动影响的实证分析

为了估计最低收购价政策对小麦市场价格波动的直接影响,利用2009年1月4日至2016年12月30日小麦现货与期货价格日数据,通过将政策作为虚拟变量引入GARCH模型,实证研究政策对平抑小麦期现货价格波动的作用,并从政策执行区和非执行区的视角比较政策在不同地区维护小麦市场价格稳定方面的效果,对模型结果和价格传导路径进行验证和分析。结果表明,政策对小麦期现货价格波动产生了明显的影响,能够显著降低小麦现货市场的波动程度,并通过期现货市场间的联系对期货市场产生影响,但政策对期货价格波动的作用方向则相反;政策在平抑小麦价格波动方面的效果具有空间上的溢出效应,通过区域间的市场联系从执行区传导到非执行区,导致非执行区价格波动程度的下降。     

A Research on Tourism Development Level Measurement and Innovation Integration Development in Bay Area of Hangzhou Bay

As a national strategic pillar industry of tourism, it is very important to explore the innovation and integration of tourism industry in Bay area of Hangzhou Bay. Based on the economic data of seven cities in Bay area of Hangzhou Bay from 2003 to 2016, this paper establishes an index system for evaluating the competitiveness of tourism industry, uses the method of information entropy weight to determine the index weight, and uses the method of standard deviation and coefficient of variation to measure the development level of tourism industry in Bay area comprehensively. The results show that:(1) The competitiveness of tourism industry in Bay area has risen slightly over the past 14 years, and the ranking of competitiveness of cities has shown a stable trend, and the trend of integration is obvious. (2) The advantages of human tourism resources in Bay area urban agglomeration are obvious. It is necessary to reorganize, complement, innovate and integrate the tourism resources of each city in the region, and take “culture + science and technology” as the driving force to promote the transformation, upgrading, innovation and development of tourism products.(3) The tourism industry in Bay area should take resource endowment as its core competitiveness, strengthen the construction of ecological environment in the whole region, seek the upgrading and expansion mode of “pan-text tourism industry” with the help of information technology and regional excellent traffic conditions, economic basis and innovation ability, and realize the leap of “quality” of the competitiveness of tourism industry in Bay area.     

农户兼业、生产性服务与水稻种植面积决策——基于11省1646户农户的实证研究

本文基于全国11省1646户农户调研数据,构建实证模型分析了农户兼业、生产性服务与水稻种植面积之间的关系。结果表明,在兼业农户比重和平均兼业水平都很高的背景下,兼业导致的“劳动力流失效应”在纯农户和兼业农户的种植面积决策中均有所体现,并且在一兼农户中表现最为显著,而“投资效应”仅体现在纯农户的种植面积决策上。接受生产性服务有助于提高各类农户的种植面积,能够缓解种稻劳动力流失对种植面积造成的负面影响,同时能够缓解一兼农户农业收入比重下降对种植面积造成的负面影响。由此,加强粮食产业生产性服务体系建设、加大纯农户粮食生产补贴力度等是稳定我国水稻生产的重要举措。     

Euro area inflation as a predictor of national inflation rates

The stability of inflation differentials is an important condition for the smooth working of a currency area, such as the European Economic and Monetary Union. In the presence of stability, changes in national inflation rates, while holding Euro area inflation fixed contemporaneously, should be only transitory. If this is the case, the rate of inflation of the whole area can also be interpreted as a predictor, at least in the long-run, of the different national inflation rates. However, in this paper we show that this condition is satisfied only for a small number of countries, including France and Italy. Better convergence results for inflation differentials are, instead, found for the USA. Some policy implications are drawn for the Eurozone.     

Higher-order Bayesian Approximations for Pseudo-posterior Distributions

The theory of higher-order asymptotics provides accurate approximations to posterior distributions for a scalar parameter of interest, and to the corresponding tail area, for practical use in Bayesian analysis. The aim of this article is to extend these approximations to pseudo-posterior distributions, e.g., posterior distributions based on a pseudo-likelihood function and a suitable prior, which are proved to be particularly useful when the full likelihood is analytically or computationally infeasible. In particular, from a theoretical point of view, we derive the Laplace approximation for a pseudo-posterior distribution, and for the corresponding tail area, for a scalar parameter of interest, also in the presence of nuisance parameters. From a computational point of view, starting from these higher-order approximations, we discuss the higher-order tail area (HOTA) algorithm useful to approximate marginal posterior distributions, and related quantities. Compared to standard Markov chain Monte Carlo methods, the main advantage of the HOTA algorithm is that it gives independent samples at a negligible computational cost. The relevant computations are illustrated by two examples.     

论新中国成立后街道校外教育的社会作用——以北京地区为中心（1949-1965）

新中国成立后,街道办事处与居委会等组织为弥补学校教育的不足,积极开展少年儿童校外教育,有效的实现了学校教育、社会教育、家庭教育的互动与结合.街居制下校外教育的发展,有效的净化了社会环境,为少年儿童的成长创建了良好的社会氛围,发挥了积极作用.     

人工智能与制造业融合:基本内涵、发展态势与内在逻辑——兼论成都人工智能与制造业融合的探索与实践

人工智能是新一轮科技革命和产业变革的重要驱动力量,人工智能与制造业融合将推动制造业加快转型升级。基于对人工智能与制造业融合的内涵、态势的分析,阐明了人工智能与制造业融合功能区的内在逻辑和分类方式,结合成都的基础条件,对人工智能与制造业融合功能区进行了分类,并借鉴国内先进经验,从加强人工智能技术和产品供给、分类推进制造业智能化、增强基础设施支撑、打造产业融合生态体系四个方面提出建议。     

广东地区高校图书馆新生入馆教育现状与创新

对广东地区33所高校的新生入馆教育现状进行调查，从教育模式、教育内容、网络化建设、技术应用等4个方面，对调查所得的数据进行分析，探究广东地区高校新生入馆教育现状和存在的问题，并进一步探讨了高校图书馆新生入馆教育创新的对策。     

基于自增强机制的矿区产业共生系统自稔性风险研究

矿区产业共生系统作为一种极具特色的产业组织形式，对区域经济的发展具有重要的驱动作用，已成为各国发展矿区经济的重要政策工具。自增强机制可以使矿区产业共生系统实现规模递增，带来协同效应和竞争优势。但同时也带来系统内企业惰性增加和适应性减弱，在外部环境发生变化时，在自增强机制的作用下，矿区产业共生系统内企业容易走上无效率的状态。因为系统内企业间信息同质性越高，系统的锁定效应和路径依赖就越明显。     

大芦家地区东二1亚段砂体微相纵横向分布研究

大芦家地区渐新统东二1亚段主要由三角洲前缘亚相组成,发育的微相类型包括河口坝、水下分流河道、水下决口扇及天然堤、远砂坝、席状砂、分流间湾等,它们在纵横向上表现出多次复合,多次叠加的特征,且各微相的界限和单砂层的界限并不一致;所有这些微相在垂向上的沉积序列可分为均一型、垂向减小型和垂向增大型三类;此外,该区三角洲体系沉积物源主要由河流从西北方向搬运而来,属高建设性的河控型三角洲,其平面呈朵状向东南方或南方延伸,其微相模式的特点是水下分流河道和河口坝沉积位于中心,其他微相分布在它们的外缘。