Computational and statistical efficiency of semiparametric gls estimators

In this note, we report a dramatic improvement in the computational efficiency of semiparametric generalized least squares(SGLS) estimation. Computation of SGLS estimates no longer presents serious problems with data sets of moderate size. We also correct a numerical error in the standard errors of the SGLS estimates reported in our recent paper in this journal (Horowitz and Neumann, 1987). The corrected standard errors of SGLS are comparable to those we reported for quantile estimates.     

Supporting women to achieve breastfeeding to six months postpartum – The theoretical foundations of a successful program

BackgroundAlthough the benefits of breastfeeding to six months are well-established, only about half of Australian women succeed. The factors associated with successful breastfeeding are rarely translated into effective interventions. A new educational and support program, called the Milky Way program has been demonstrated to be effective in supporting women to achieve prolonged breastfeeding. In the Milky Way program, breastfeeding is considered an embodied performance which requires an engaged combination of body, mind and spirit. This paper aims to explain how the two theories that informed the program were used to better enable women's long term breastfeeding success.MethodThe theory of self-efficacy is first described as a way to develop women's cognitive processes to organise and execute the course of actions to breastfeed for a longer period of time. Birth territory theory is then presented. This theory discusses women as embodied selves; an essential concept for breastfeeding success. Birth territory theory also describes the effects of the holistic environment on the woman and explores the effects of power that is used in the environment. This power can be used integratively to strengthen the woman's breastfeeding confidence and success or, disintergratively which reduces her confidence and undermines her success.ConclusionStrategies based on self-efficacy theory are helpful, but are not sufficient to promote breastfeeding to six months. Health educators also need to foster the woman's connection to, and trust in, her body and her baby's body to breastfeed spontaneously. Being aware of environmental impacts on how the woman and baby breastfeed; and using one's own power integratively is crucial to women being able to achieve prolonged breastfeeding.     

穿行的镜头——德勒兹眼中电影的三道流束

在德勒兹的《运动——影像》一书中,他认为在电影中无时无刻都存在着由整体集合、镜头和全体时延所构成的三道流束,三者相互区隔,又彼此包围。那么,这三道流束在影片中具体是如何实现,又是怎样相互协调发展的?针对这个问题,采用理论分析和例证说明的方法进行研究,具体分析德勒兹眼中的三道流束。     

MICROBEHAVIORS IN GROUP DECISION-MAKING

An exploratory field experiment sought to study the effects of three levels of task complexity on the decision-making patterns of seven long term, on-going task groups. Decision-making was identified as consisting of five behaviors; namely, organization, information exchange, alternative generation, evaluation, and non-task behaviors. The results confirmed the predictions for alternative generation and non-task behaviors: alternative generation occurred most frequently with moderate task complexity; non-task behaviors occurred the least frequently at the level of moderate complexity. The organization behavior increased with increasing task complexity, while information exchange and evaluation showed no differences in frequency of occurrence across the three levels of complexity.     

An investigation of duration dependence in the American stock market cycle

This paper investigates the duration dependence of the US stock market cycles. A new classification method for bull and bear market regimes based on the crossing of the market index and its moving average is proposed. We show evidence of duration dependence in whole cycles. The half cycles, however, are found to be duration independent. More importantly, we find that the degree of duration dependence of the US stock market cycles has dropped after the launch of the NASDAQ index.     

著作权保护期限制之理论思考

著作权保护存在期限限制,这是著作权与有形财产的重要区别之一。著作权保护期限制的正当性可以从经济学、著作权法的公共利益、著作权法的社会政策以及利益平衡等方面加以认识。确定著作权保护期的因素可以从宏观和微观方面分析。著作权保护期在存在一致性的同时,也存在一些特殊性。      

我国基金投资者的处置效应——基于交易帐户数据的持续期模型研究

本文建立既考虑“内在时间”（inherent time）影响,又处理了样本数据审查（censored）问题的持续期模型,采用4只投资基金的31万多帐户交易数据作为样本,系统研究了我国基金投资者的处置效应。结果表明：尽管基金的周转率远低于股票交易周转率,基金投资者仍然存在明显的处置效应;在控制投资者持有基金的时间对其条件卖出概率的影响后,证实基金投资者的处置效应不但与投资者的累计盈亏有关,而且与基金近期的涨跌有关。本研究还发现：机构投资者的处置效应要弱于个人投资者,前景理论效应并不明显。在相同条件下,年龄越大的投资者持有基金的时间较长,处置效应也越明显。     

关系资产与中非间贸易:基于40国面板数据的实证研究

中非间长期友好关系是否产生贸易促进效应是双方外交关系可持续性及各自应对外部冲击能力的重要支撑，基于中非间较同质化的外交关系资产背景，通过引入弱惩罚和强惩罚机制的关系持续期和以外交关系等级衡量的投资强度变量来测度关系资产，以克服外交活动与贸易间存在的内生性问题，并纳入冲突力对中非间关系的影响，并利用2001～2017年非洲40国贸易数据构建面板校正误差模型，考察中非国家间关系资产对双边贸易及细分初级产品和制成品贸易是否存在促进效应。研究表明，关系资产对中非贸易有显著促进作用，但存在两个相反的关系资产对贸易影响机制，即关系持续期作为非纯公共产品的贸易促进作用和对较大经济规模国家的贸易摊薄效应；中国经济增长对中非双向出口贸易有较强带动作用，对非洲国家关税减免政策具有互惠特征，对中非双边贸易均有明显促进作用，但对不同细分品类具有差异化影响；中国和非洲国家应合力提升关系投资强度，以进一步发挥惯性力和国家间关系的贸易提升力作用，以贸易促进支撑中非全面战略合作伙伴关系的发展。     

中国家族企业网络化成长模式：基于东西部地区问卷调查结果的统计分析

基于浙江、重庆等东西部省市266家样本家族企业的调查数据,探讨了中国家族企业网络化成长模式的主要类型、基本特征,构建途径,并从企业内外角度进行了比较,主要结论是:家族企业与其他企业的关系以购买原材料、机器设备、零部件和接受订单(代工)为主,与其他机构的关系以技术咨询、资金借贷、管理咨询、委托产品开发为主;注重促进与产业价值链中其他企业关系的长期化,强调与本地政府主管部门和金融机构的关系;网络化成长模式主要通过朋友和其他关系构建,通过家族关系构建的比例很低,并主要受地理区域、产业属性、组织结构、企业规模、权力结构、企业家特质等因素的影响.     

Nonparametric recovery of duration distrbutions from cross-sectional sample surveys

When lifetimes consist of two phases, and information about a population must be based on a cross-sectional sample, it is sometimes possible to estimate nonparametrically the phase duration distributions, even though the phase durations themselves are not observed. The key requirements are that the process sampled must be stationary, and that the observations at the time of cross-section include the age and phase of each sampled lifetime at the time of sampling. The estimation procedures must allow for length-bias even when the relevant lengths are not recorded. Stronger results are available when certain parametric assumptions are satisfied about the relationship of the phase durations to the total lifetime, or alternatively when it is also possible to record the total lifetime from a follow-up survey.