基于生态文明理念下化解城乡生态环境二元化的路径选择

改革开放30多年以来,我国城乡经济发生了翻天覆地的变化,城乡居民经济水平和生活质量都得到了普遍提升。但随着城市化、工业化进程加快,城乡经济也随之拉开差距,在城乡经济结构二元化的影响下,城乡生态环境也出现了严重的二元化趋势。介于此,本文以"天人合一、人地和谐"的生态文明理念为指导思想,在挖掘生态文明与生态环境保护两者内在关系的基础上,结合实际以分析我国城乡生态环境严重二元化的现况为出发点,剖析导致城市与乡村生态环境二元化的三大矛盾,并提出六大破解城乡生态环境二元结构可行之路,为共同构建美好生态环境提供良策。     

Maximum likelihood estimation of a binomial proportion using one‐sample misclassified binary data

In this article, we construct two likelihood‐based confidence intervals (CIs) for a binomial proportion parameter using a double‐sampling scheme with misclassified binary data. We utilize an easy‐to‐implement closed‐form algorithm to obtain maximum likelihood estimators of the model parameters by maximizing the full‐likelihood function. The two CIs are a naïve Wald interval and a modified Wald interval. Using simulations, we assess and compare the coverage probabilities and average widths of our two CIs. Finally, we conclude that the modified Wald interval, unlike the naïve Wald interval, produces close‐to‐nominal CIs under various simulations and, thus, is preferred in practice. Utilizing the expressions derived, we also illustrate our two CIs for a binomial proportion parameter using real‐data example.     

Distributional effects of environmental taxes on transportation: evidence from Engel curves in the United States

Indirect taxes on transportation activities that pollute can correct externalities and close the gaps between private and social costs. However, policy makers often find such Pigou taxes difficult to implement because of political resistance due to possibly adverse affects on equity. For this reason it is important to assess the distributional aspects of environmental levies. This article estimates properties of the demand for transportation in parametric and non-parametric analyses of Consumer Expenditure Surveys for the United States and finds patterns in the resulting set of Engel curves. Private transportation using air flights and new cars has Engel elasticity above unity while public transportation via mass transit has Engel elasticity below unity. The findings can be interpreted in an important way since they show that a differentiated scheme of environmental taxes on transportation may function progressively. A Pigou scheme with larger taxes on modes of transportation that pollute more appears to coincide with larger levies on luxury modes preferred by richer households.     

我国非处方药（OTC）流通渠道模式研究

目前,我国OTC药品年销售额已超过400亿元人民币,年平均增长速度超过20%,成为世界上增长最快的市场。与此同时,各种体制的医药商业公司蓬勃发展起来;许多制药企业成立了自己的销售公司;外资药店攻城掠地;其他行业巨头大举入侵,使得OTC市场的流通渠道经历着前所未有的巨变。本文在分析OTC流通渠道模式的基础上,针对OTC厂商提出一些渠道建议。     

全球粮食安全风险格局时空特征分析

[目的]当前全球范围内公共安全事件频繁发生,严重影响了世界粮食生产和供应链,粮食安全系列问题由此引发学术界与政府部门广泛关注。贸易流通不稳定的背景下,科学分析全球粮食安全和风险格局时空特征对维护国家粮食安全以及保障全球经济社会可持续发展具有重要意义。然而,以往研究缺乏对全球粮食安全和风险格局的长时序时空特征分析。文章通过结合粮食生产和消费数据对全球粮食安全和风险格局进行长时间序列研究,并探索全球粮食安全和风险格局时空规律。[方法]基于1961—2017年全球各国粮食生产和消费统计数据,综合运用波动系数、重心分析、粮食短缺指数和相对资源承载力模型等分析方法,对全球粮食生产、消费、风险及相对风险格局进行了分析,探究了全球粮食安全和风险格局的时空规律。[结果]（1）研究期间全球和中国粮食生产及消费呈显著上升趋势,疫情和蝗灾等重大突发事件会对粮食生产消费格局造成一定影响;（2）全球整体粮食安全总体从中等风险下降至低风险,中国粮食安全风险近60年持续降低,2017年处于低风险等级;（3）中国粮食资源承载力略高于全球平均水平,非洲、拉丁美洲以及东南亚地区粮食安全相对风险波动较大。[结论]世界粮食安...     

老年人养老方式选择的影响因素研究——基于CHARLS数据的实证分析

本研究在CHARLS调查所获得的微观数据的基础上进行,首先对老年人养老方式选择的结果和老年人人口特质、健康状况、经济状况等方面的6个变量进行关联分析,再通过二项Logistic回归模型,将是否选择机构养老作为被解释变量进行回归分析。结果表明非机构养老方式仍是老年人的主要选择,年龄、婚姻状况、慢性疾病情况、经济状况等因素与老年人养老方式的选择存在显著的关联并对选择结果产生影响。     

建设工程交易模式和交易机制设计框架

建设工程交易模式和交易机制确定了工程交易的规则以及项目参与者的工作范围、权利、责任和义务,从而直接影响到项目的成败。本文基于物理-事理-人理(WSR)方法论,建立工程交易模式和交易机制的设计框架。工程物理空间结构构成物理维;人作用于物的工程实施过程是,构成事理维,反应工程的时间结构;工程交易各方协作机制构成人理维,即为工程交易机制。工程的物理维和事理维确定的工程交易对象、工程交易模式的设计包括:业主方的管理方式的设计、工程发包方式的设计和合同类型的选择。工程交易机制的设计包括:招标机制设计、合同设计、担保机制和合同机制设计等。这个统一的框架为工程交易治理机制的设计提供了完整的解决方案。     

农户参与林业碳汇意愿及影响因素动态分析——以云南省凤庆县、镇康县为例

运用农户调查数据,采用计量经济学分析方法,建立模型对农户参与意愿的影响因素进行了动态分析。结果显示,在项目涉及区,文化程度,家庭劳动力人数,家庭人均收入,林业收入占家庭收入比例,农户环保意识,对碳汇林未来经济预期六个变量对农户的参与意愿影响显著;在非项目涉及区,文化程度,林业收入占家庭收入比例,林地面积,农户环保意识,对碳汇林未来经济预期六个变量对农户的参与意愿影响显著。针对存在的问题,提出提高林业碳汇补偿标准、开展农户教育培训活动、拓展农户收入来源的建议。     

商务英语阅读新思维模式的建构

习得语言要对比目标语与本族语的语言表达差异,更要对比二者思维模式的差异。习得者在未精通一门外语之前,常常倾向于使用熟悉的本族语思维来套用目的语思维,形成思维定式。在商务英语阅读中,有必要解构习惯汉语思维的习得者在阅读中的内在思维模式,以建构适应型的阅读新思维模式。     

Time-series–cross-section Data

This article treats the analysis of 'time-series–cross-section' (TSCS) data. Such data consists of repeated observations on a series of fixed units. Examples of such data are annual observations on the political economy of OECD nations in the post-war era. TSCS data is distinguished from 'panel' data, in that asymptotics are in the number of repeated observations, not the number of units.
The article begins by treating the complications of TSCS data in an 'old-fashioned' manner, that is, as a nuisance which causes estimation difficulties. It claims that TSCS data should be analyzed via ordinary least squares with 'panel correct standard errors' rather than generalized least squares methods. Dynamics should be modeled via a lagged dependent variable or, if appropriate, a single equation error correction model.
The article then treats more modern issues, in particular, the modeling of spatial effects and heterogeneity. It also claims that heterogeneity should be assessed with 'panel cross-validation' as well as more standard tests. The article concludes with a discussion of estimation in the presence of a binary dependent variable.