西汉河间献王的学术与政治倾向

学界通常梳理、分析西汉河间献王的学术目的和学术活动,重视他的伉直的秉性和本真的学风,而对他的学术背后的政治倾向多有所忽略。河间献王刘德重视保护儒学的古文经典,招纳儒生汇聚,认同士人主流政治思想。这其中有其特殊的政治意味：既是对新政的一种构思,也是对当时武帝政策的一种策略性的批评。     

重金属污染的媒体再现与科学真实比较——对2000-2010年间广东省内报纸的内容分析

本研究旨在探讨广东省内主要媒体自2000年至2010年来对重金属污染的报道。我们以《南方日报》、《广州日报》、《南方都市报》和《羊城晚报》中与重金属污染有关的新闻报道作为样本,分析媒体所强调的议题、报道频次等方面的变化。通过将媒体再现与广东省重金属污染的科学发现比较,本研究发现广东省内媒体对于重金属污染的议题呈现与科学真实存在较大差异。     

Efficient estimation for time series following generalized linear models

In this paper, we consider James–Stein shrinkage and pretest estimation methods for time series following generalized linear models when it is conjectured that some of the regression parameters may be restricted to a subspace. Efficient estimation strategies are developed when there are many covariates in the model and some of them are not statistically significant. Statistical properties of the pretest and shrinkage estimation methods including asymptotic distributional bias and risk are developed. We investigate the relative performances of shrinkage and pretest estimators with respect to the unrestricted maximum partial likelihood estimator (MPLE). We show that the shrinkage estimators have a lower relative mean squared error as compared to the unrestricted MPLE when the number of significant covariates exceeds two. Monte Carlo simulation experiments were conducted for different combinations of inactive covariates and the performance of each estimator was evaluated in terms of its mean squared error. The practical benefits of the proposed methods are illustrated using two real data sets.     

基于好评返现和差评偏好的体验型产品两阶段定价决策研究

假定产品存在发布试销期与正式销售期,在销售商不采取好评返现与采取好评返现两种情形下分别建立考虑消费者差评偏好的两阶段定价决策模型,用KT方法得到相应的最优决策和利润,给出了销售商实施好评返现的条件。基于导函数分析方法与数值仿真技术,分析了好评返现与差评偏好对产品定价、销售商利润和消费者效用的影响,证实了好评返现下消费者重视差评信息的合理性,并针对消费者、平台和销售商提出了对策。研究表明:只有产品质量中等的销售商才会采取好评返现策略,其利润随产品质量的提升而先递增后递减;好评返现提高了销售商第二阶段的市场份额和售价,导致消费者效用损失;消费者越重视差评信息,实施好评返现的高(低)质量产品销售商越多(少),且销售商利润将下降;好评返现扭曲了评价信息的真实性,降低了消费者对在线评价系统的信任度。     

Robust estimation for longitudinal data under outcome‐dependent visit processes

In longitudinal data where the timing and frequency of the measurement of outcomes may be associated with the value of the outcome, significant bias can occur. Previous results depended on correct specification of the outcome process and a somewhat unrealistic visit process model. In practice, this will never exactly be the case, so it is important to understand to what degree the results hold when those assumptions are violated in order to guide practical use of the methods. This paper presents theory and the results of simulation studies to extend our previous work to more realistic visit process models, as well as Poisson outcomes. We also assess the effects of several types of model misspecification. The estimated bias in these new settings generally mirrors the theoretical and simulation results of our previous work and provides confidence in using maximum likelihood methods in practice. Even when the assumptions about the outcome process did not hold, mixed effects models fit by maximum likelihood produced at most small bias in estimated regression coefficients, illustrating the robustness of these methods. This contrasts with generalised estimating equations approaches where bias increased in the settings of this paper. The analysis of data from a study of change in neurological outcomes following microsurgery for a brain arteriovenous malformation further illustrate the results.     

知识可以改变对转基因食品的态度吗?——探究科技争议下的极化态度

文章探讨了生物技术知识与公众对转基因态度之间的关系。通过检视不同时代、不同国情背景下的调研数据,发现掌握生物技术知识的程度在总体上并不能与人们对转基因的态度形成稳定的正相关性。相反,在不同国家以及转基因争议的不同阶段,生物技术知识和受众学历在影响人们对转基因的态度上作用似乎不同。通过系统探讨转基因争议的媒体因素与心理机制推断:造成这种不同的主要原因是,在争议情景下,人们出于本能的自我保护性心理认知机制被激活,取代了他们利用知识进行理性衡量的认知手段。这一研究为理解科技争议与极化态度的形成提供了一个解释框架。     

A method for parameter estimation of non-linear regression with autocorrelated errors

For a class of non-linear models with stationary dependent residuals an estimating procedure is introduced and its statistical properties are derived. This procedure is useful when no basis exists for assuming a specific parametric model for the error process. For application of the procedure a two step iterative method is described and a small simulation study is performed.     

Sufficient admissibility conditions for scale parameter estimator

Although there are a number of results available for the admissibility of the best translation equivariant estimator of the parameter, there is hardly any stated explicitly for the best scale equivariant estimator of the scale parameter. In this paper, we derive sufficient conditions for the admissibility of the scale parameter estimators and compara them. The derivations use the well known results due to Brown [1], Farrell [2], and Portnoy [3]. The loss function has been taken to be quadratic.