我国是否进入“刘易斯转折点”——文献述评及思考

本文梳理已有研究文献,将关于我国是否进入刘易斯转折点的观点归纳为三种:第一种观点认为我国已全面进入刘易斯转折点阶段;而第二种观点持相反意见,认为民工荒是特殊背景下的结构性失衡现象,我国农村劳动力供大于求的总体态势不会轻易发生逆转;第三种观点则认为我国经济处于中国特色的刘易斯转折点区间内。从不同视角认识这些争论有助于我们更好地把握刘易斯转折点,应对日益严峻的民工荒现象,更好地利用和兑现人口红利以及做好迎接刘易斯转折点的准备,实现我国经济由二元结构向一元结构的协调转型。     

不确定性感知与企业绿色技术创新——基于区域与企业异质性视角的分析

实现碳达峰碳中和是推动高质量发展的内在要求,企业积极开展绿色技术创新有利于实现经济的绿色可持续发展。在面对宏观环境的经济政策不确定时,企业对不确定性的感知能力能否帮助企业发挥抵抗风险作用？能否将外部经济政策不确定性转化为企业的内在发展动力实现绿色技术创新?文章探究企业经济政策不确定性的感知程度对其绿色技术创新的影响,并分析了其中的作用机制。在此基础上使用2007—2020年中国沪深A股上市公司数据和企业层面经济政策不确定性指标等数据进行实证检验,并提出政策建议。研究发现,企业经济政策不确定性感知程度的增加能够促进企业绿色技术创新水平的提高。机制分析表明,从外部融资视角看,经济政策不确定性感知的增加可以通过缩小信息不对称与减小企业融资约束提高企业的绿色技术创新能力;从企业内部管理视角看,经济政策不确定性感知的增加能够通过增强企业战略积极性和提升绿色认知能力来提高企业的绿色技术创新能力。通过企业外部地区特征与内部自身特征异质性分析发现,企业所在地区经济发展水平、数字经济发展程度与地区创新活力越高,越有利于企业经济政策不确定性感知促进绿色技术创新,对于非重污染、社会责任表现较差、自身风险承担水平较低的企业这一促进作用更为明显。进一步分析政企互动关系发挥的作用发现,国有企业与政府环境规制水平较高地区的企业拥有更强的绿色创新能力,而政府环保补贴在这一过程中发挥的作用并不充分。研究结论对我国企业实现绿色技术创新具有重要的启示:企业需要充分把握市场信息与市场机遇,树立可持续发展目标;政府需要积极缩小企业与市场、企业与政府间的信息不对称,强化地区创新活力,针对不同地区与类型企业实施经济政策;政府应当完善经济政策平稳机制,积极引导企业正确认知经济政策不确定性带给企业的机会与风险,发挥好政府调节作用,加快实现企业的绿色技术创新与绿色转型发展。     

Semiparametric Estimation of a Proportional Hazard Model with Unobserved Heterogeneity

The proportional hazard model with unobserved heterogeneity gives the hazard function of a random variable conditional on covariates and a second random variable representing unobserved heterogeneity. This paper shows how to estimate the baseline hazard function and the distribution of the unobserved heterogeneity nonparametrically. The baseline hazard function and heterogeneity distribution are assumed to satisfy smoothness conditions but are not assumed to belong to known, finite-dimensional, parametric families. Existing estimators assume that the baseline hazard function or heterogeneity distribution belongs to a known parametric family. Thus, the estimators presented here are more general than existing ones.     

Semiparametric analysis of transformation models with doubly censored data

Double censoring arises when T represents an outcome variable that can only be accurately measured within a certain range, [L, U], where L and U are the left- and right-censoring variables, respectively. In this note, using Martingale arguments of Chen et al. [3 Chen, K., Jin, Z. and Ying, Z. 2002. Semiparametric analysis of transformation models with censored data. Biometrika, 89: 659–668. [Crossref], [Web of Science ®] [Google Scholar]], we propose an estimator (denoted by ?β) for estimating regression coefficients of transformation model when L is always observed. Under Cox proportional hazards model, the proposed estimator is equivalent to the partial likelihood estimator for left-truncated and right-censored data if the left-censoring variables L were regarded as left-truncated variables. In this case, the estimator ?β can be obtained by the standard software. A simulation study is conducted to investigate the performance of ?β. For the purpose of comparison, the simulation study also includes the estimator proposed by Cai and Cheng [2 Cai, T. and Cheng, S. 2004. Semiparametric regression analysis for doubly censored data. Biometrika, 91: 277–290. [Crossref], [Web of Science ®] [Google Scholar]] for the case when L and U are always observed.     

Two-dimensional density estimation using smooth invertible transformations

We investigate the problem of estimating a smooth invertible transformation f when observing independent samples X₁,…,X_n∼P°f where P is a known measure. We focus on the two-dimensional case where P and f are defined on R². We present a flexible class of smooth invertible transformations in two dimensions with variational equations for optimizing over the classes, then study the problem of estimating the transformation f by penalized maximum likelihood estimation. We apply our methodology to the case when P°f has a density with respect to Lebesgue measure on R² and demonstrate improvements over kernel density estimation on three examples.     

Construction of optimal supersaturated design with large number of levels

Inspired by the ideas of column and row juxtaposition in Liu and Lin (2009) and level transformation in Yamada and Lin (1999), this paper presents a new method for constructing optimal supersaturated designs (SSDs). This method provides a convenient way to construct mixed-level designs with relatively large numbers of levels, avoiding the blind search and numerous calculations by computers. The goodness of the resulting SSDs is judged by the χ² (Yamada and Lin, 1999 and Yamada and Matsui, 2002) and J₂ (Xu, 2002) criteria. Some nice properties of the new designs are also provided.     

Distribution-free test in Tobit mean regression model

This paper discusses the problem of fitting a parametric model in Tobit mean regression models. The proposed test is based on the supremum of the Khamaladze-type transformation of a partial sum process of calibrated residuals. The asymptotic null distribution of this transformed process is shown to be the same as that of a time-transformed standard Brownian motion. Consistency of this sequence of tests against some fixed alternatives and asymptotic power under some local nonparametric alternatives are also discussed. Simulation studies are conducted to assess the finite sample performance of the proposed test. The power comparison with some existing tests shows some superiority of the proposed test at the chosen alternatives.     

社会转型时期群体性治安事件的现状及对策

在当前社会变革体制转换利益调整的大背景下,人民内部矛盾随着各种诱发因素的此消彼长,不断滋生发展、蔓延、转化,呈数量增多、复杂性加剧之势。由此引发的群体性事件也日趋突出,妨害社会和经济秩序,影响社会稳定,阻碍社会主义建设事业的发展。     

基于奈达理论的文化转化策略和技巧

文学翻译是人类跨语言交际和跨文化交际的一种重要手段,由于文化差异和碰撞而不可避免地会在文化转化方面遇到难题。美国的尤金.奈达提出的一系列翻译理论对解决这方面难题具有重要理论和实践上的指导意义。笔者着重就奈达的翻译信息论、对等论和读者反应论,详细探究了如何基于奈达理论并加以灵活运用,从而提高文学翻译中的文化转化策略和技巧,以更加完美地再现原文的艺术美与文化信息。     

政府数字化转型中公共机构人员数字素养：框架构建、实践困境与提升路径

选取苏南、苏中、苏北代表性地区的典型部门人员为访谈对象,以半结构化访谈的方式,基于扎根理论研究方法,借助NVivo11 Pro软件,从“心理-能力”角度构建公共机构人员数字素养框架。研究发现,政府数字化转型中公共机构人员存在数字素养水平不均衡、数字技能学习不深入、数字培训体系不健全、数据共享流通不充分等问题,可以通过构建差异化的考评体系、场景式的实践体系、全覆盖的培训体系、系统性的共享体系等方式提升公共机构人员数字素养水平。