Some maximum-indifference estimators for the slope of a univariate linear model

As known, the least-squares estimator of the slope of a univariate linear model sets to zero the covariance between the regression residuals and the values of the explanatory variable. To prevent the estimation process from being influenced by outliers, which can be theoretically modelled by a heavy-tailed distribution for the error term, one can substitute covariance with some robust measures of association, for example Kendall's tau in the popular Theil–Sen estimator. In a scarcely known Italian paper, Cifarelli [(1978), ‘La Stima del Coefficiente di Regressione Mediante l'Indice di Cograduazione di Gini’, Rivista di matematica per le scienze economiche e sociali, 1, 7–38. A translation into English is available at http://arxiv.org/abs/1411.4809 and will appear in Decisions in Economics and Finance] shows that a gain of efficiency can be obtained by using Gini's cograduation index instead of Kendall's tau. This paper introduces a new estimator, derived from another association measure recently proposed. Such a measure is strongly related to Gini's cograduation index, as they are both built to vanish in the general framework of indifference. The newly proposed estimator is shown to be unbiased and asymptotically normally distributed. Moreover, all considered estimators are compared via their asymptotic relative efficiency and a small simulation study. Finally, some indications about the performance of the considered estimators in the presence of contaminated normal data are provided.     

所为非所想?农户风险管理意愿与行为的悖离分析

实现农户风险管理意愿与行为统一是降低农业风险对农户农业生产负面影响的重要途径。利用2018年东北三省和湖北省种植大户的调查数据,从自然风险与市场风险两方面,对农户风险管理的意愿、行为及其悖离进行分析,并探究形成悖离的原因。研究发现：对于自然风险,大部分农户使用了有效的风险管理工具,但风险管理意愿不高;农户的市场风险管理行为极为少见,与之相悖的是,农户具有较高的市场风险管理意愿。结果表明,风险管理实际行为控制、风险管理执行意愿和风险管理外部环境是影响农户自然风险管理意愿与行为悖离的主要因素;此外,农户对农业保险缺乏了解,以及目前农业保险存在的不足也是导致此悖离的重要原因;风险管理执行意愿和风险管理外部环境是影响农户市场风险管理意愿与行为悖离的主要因素。此外,农户获取信息渠道不足,对市场风险管理工具缺乏了解,甚至存在明显的误解与不信任也是导致农户市场风险管理意愿与行为悖离的重要原因。因此,为了有效实现农户风险管理意愿与行为的统一,应健全农业保险的推广机制,加强市场风险管理的宣传,扩大“保险+期货”的试点,发挥新型主体的带动作用。     

《了不起的盖茨比》中威尔逊形象的生态解读

自2007年起,从生态批评的角度对《了不起的盖茨比》进行分析,逐渐成为学者研究的一个热门方向,然而绝大多数学者将目光集中在主要人物上,忽略了另一位极具代表性的小人物——威尔逊。威尔逊这一人物形象具有诸多意义,仅从生态角度来说,他便折射出了“爵士时代”下人与自然、人与社会以及人与自身的关系。通过利用生态批评这一理论工具,从自然生态、社会生态和精神生态这三个角度出发,对威尔逊的人物形象进行分析探讨,以期能够透过对于威尔逊的解读,得到对“爵士时代”中的人与自然、社会以及自身关系的更全面和深刻的认识。     

State transition modeling of complex monitored health data

This article considers the analysis of complex monitored health data, where often one or several signals are reflecting the current health status that can be represented by a finite number of states, in addition to a set of covariates. In particular, we consider a novel application of a non-parametric state intensity regression method in order to study time-dependent effects of covariates on the state transition intensities. The method can handle baseline, time varying as well as dynamic covariates. Because of the non-parametric nature, the method can handle different data types and challenges under minimal assumptions. If the signal that is reflecting the current health status is of continuous nature, we propose the application of a weighted median and a hysteresis filter as data pre-processing steps in order to facilitate robust analysis. In intensity regression, covariates can be aggregated by a suitable functional form over a time history window. We propose to study the estimated cumulative regression parameters for different choices of the time history window in order to investigate short- and long-term effects of the given covariates. The proposed framework is discussed and applied to resuscitation data of newborns collected in Tanzania.     

Statistical inference based on generalized Lindley record values

This paper addresses the problems of frequentist and Bayesian estimation for the unknown parameters of generalized Lindley distribution based on lower record values. We first derive the exact explicit expressions for the single and product moments of lower record values, and then use these results to compute the means, variances and covariance between two lower record values. We next obtain the maximum likelihood estimators and associated asymptotic confidence intervals. Furthermore, we obtain Bayes estimators under the assumption of gamma priors on both the shape and the scale parameters of the generalized Lindley distribution, and associated the highest posterior density interval estimates. The Bayesian estimation is studied with respect to both symmetric (squared error) and asymmetric (linear-exponential (LINEX)) loss functions. Finally, we compute Bayesian predictive estimates and predictive interval estimates for the future record values. To illustrate the findings, one real data set is analyzed, and Monte Carlo simulations are performed to compare the performances of the proposed methods of estimation and prediction.     

智力资源对物质资源的部分替代与我国集约经济的发展

任何生产活动都需要一定的资源,投入资源之间会形成一定的比例。在很多情况下,投入资源之间的比例是可变的,即资源之间存在着一定程度的替代关系。理想的状况是,是根据各种资源的稀缺程度、效率等因素对其进行合理组合。根据我国经济发展的状况以及资源秉赋,我国应增加智力资源的投入、减少物质资源的消耗,即实现智力资源对物质资源的部分替代,这种替代具有很强的必要性、可能性和现实性。     

“自然历史”：阿多诺对自然的重构

启蒙理性遵循同一性逻辑。同一性意味着概念与实在的分离,且概念替代实在并拥有对实在的控制权。其结果,自我保存理性将内外自然彻底剥离,并实现了对自然的全面统治。否定辩证法的根本特征是否定性,其核心即矛盾,矛盾双方具有向对立面转化的潜能。在阿多诺否定辩证法的框架内,自然并非仅指同一性所赋予的外观——历史的维度,同时也具有原始自然的维度。自然是一种矛盾的存在,而且,它总是处于历史对它的否定与抵抗中,在具有反思性的否定中,自然获得了重建与救赎的可能。阿多诺的自然理论对破除自然与历史、主体与客体的对立具有积极的意义,但他对自然的理解具有观念性,且否定辩证法本身有一定的悖论性。     

波兰语义学派NSM理论对情感词汇的语义解释力

每种语言都为本民族提供了一套阐释范畴,并按照不同的认知图景使人们的情感体验概念化。这些认知图景又与特定语言的词汇范畴联系在一起,因而赋予了特定文化的价值、态度和意义。波兰语义学派的自然语义元语言(NSM)理论从跨语言和跨文化的视角来研究情感概念及其意义。通过梳理前人的有关论述,以自然语义元语言理论为框架,以普遍性语义基元为释义单位,探讨了NSM理论的化简释义方法及其对情感词汇的语义解释力,展示了应用NSM这一用途广泛的释义工具来准确地表征情感概念的意义。普遍的人类概念是构成人类理解情感概念的基石。基于60多个人类普遍概念的NSM研究方法,无疑将有助于我们更好地理解和把握不同文化的人类情感概念。     

Improved two-parameter estimators for the negative binomial and Poisson regression models

Negative binomial regression (NBR) and Poisson regression (PR) applications have become very popular in the analysis of count data in recent years. However, if there is a high degree of relationship between the independent variables, the problem of multicollinearity arises in these models. We introduce new two-parameter estimators (TPEs) for the NBR and the PR models by unifying the two-parameter estimator (TPE) of Özkale and Kaç?ranlar [The restricted and unrestricted two-parameter estimators. Commun Stat Theory Methods. 2007;36:2707–2725]. These new estimators are general estimators which include maximum likelihood (ML) estimator, ridge estimator (RE), Liu estimator (LE) and contraction estimator (CE) as special cases. Furthermore, biasing parameters of these estimators are given and a Monte Carlo simulation is done to evaluate the performance of these estimators using mean square error (MSE) criterion. The benefits of the new TPEs are also illustrated in an empirical application. The results show that the new proposed TPEs for the NBR and the PR models are better than the ML estimator, the RE and the LE.     

Double robust estimator in general treatment regimes based on Covariate-balancing

Double robust estimators have double the chance of being a consistent estimator of a causal effect in binary treatments cases. In this paper, we proposed an estimator of a causal effect for general treatment regimes based on covariate-balancing. Under parametrical situation, our estimator has double robustness.