Towards Uniformly Efficient Trend Estimation Under Weak/Strong Correlation and Non‐stationary Volatility

In this paper, we consider the deterministic trend model where the error process is allowed to be weakly or strongly correlated and subject to non‐stationary volatility. Extant estimators of the trend coefficient are analysed. We find that under heteroskedasticity, the Cochrane–Orcutt‐type estimator (with some initial condition) could be less efficient than Ordinary Least Squares (OLS) when the process is highly persistent, whereas it is asymptotically equivalent to OLS when the process is less persistent. An efficient non‐parametrically weighted Cochrane–Orcutt‐type estimator is then proposed. The efficiency is uniform over weak or strong serial correlation and non‐stationary volatility of unknown form. The feasible estimator relies on non‐parametric estimation of the volatility function, and the asymptotic theory is provided. We use the data‐dependent smoothing bandwidth that can automatically adjust for the strength of non‐stationarity in volatilities. The implementation does not require pretesting persistence of the process or specification of non‐stationary volatility. Finite‐sample evaluation via simulations and an empirical application demonstrates the good performance of proposed estimators.     

四川盆地中三叠世盐盆分布与演化特征研究

四川盆地卤水分布广泛，资源丰富, 早为世人所瞩目，中三叠统雷口坡组是四川盆地最早开采天然气和盐卤的层系之一。根据盆地雷口坡组大量钻井资料研究表明，盆地雷口坡组主要成盐期分别为雷三2 期和雷四2 期，在盆地东部和南部由于受到古隆起的影响，盐岩地层已被剥蚀难以保存，现今盐岩主要分布在开江古隆起和泸州古隆起的西部以及天井山古隆起的南部（华蓥山以西—龙门山以东的川西—川中地区）。印支运动对盆地雷口坡组盐岩在平面的迁移起着十分重要的作用，根据不同时期盐岩统计数据看，两期盐盆在平面上具有向西迁移、叠加的特征，其中川中的GS1 井就钻遇了这两期的盐岩。     

悬搁伦理学的政治学——霍布斯的实践哲学方法

亚里士多德与霍布斯的实践哲学都是针对多元善的伦理事实的某种反思,但两者的理论诉求不同。考虑到人类行动者善观念的多元性和相对性,亚里士多德追问的是:"属人的、就其自身而言的善是什么",他由此走上了伦理学道路;对亚里士多德来说,政治学探究以伦理学为基础。霍布斯关注的是这一事实的实践后果,即人际冲突;由此,他提出的问题是:"应该怎样解决冲突",霍布斯也就绕过伦理学,直接走上了政治学的道路。也就是说,相较于亚里士多德的实践哲学范式,霍布斯的政治学悬搁了伦理学基础。这一新的政治学方法不是中立的,它蕴涵了自由主义的政治观念。霍布斯创立这一新方法的更深层原因或许是其"目的论的宇宙论"观念的瓦解。     

指数函数和对数函数的高精度快速算法

指数、对数函数的数值计算是一种最基本的算术操作,研究其快速算法,对于科学计算、数据处理,尤其是要求运算精度很高的实时控制系统,有着非常重要的意义.通过数值分析,考虑到精度要求较高,计算量和数表的存储空间这三个因素,结合计算和查表的方法给出了一些基本函数的快速算法.另外,还介绍了改进的高精度快速算法并演示了详细的计算过程.得出精度越高,内存越大,相应的操作速度却没有下降。     

大豆生产者补贴政策改革促进农户种植结构调整了吗?——基于全国446个县的准自然实验

以大豆生产者补贴政策改革作为切入点,将政策实施地区和非实施地区视为一次部分省份优化大豆、玉米种植结构的准自然实验,通过构建PSM-DID模型,考察大豆生产者补贴政策改革对农户种植结构调整的影响及其作用机制.结果表明:(1)大豆生产者补贴政策改革对农户种植结构调整具有显著的时间异质性,政策改革初年(2017年)大豆与玉米的面积之比显著提高6.5％,虽然2018年大豆与玉米的相对补贴额度出现大幅度增长,但大豆与玉米的面积之比仅显著提高3.4％;(2)预期相对收益的提升是2017年农户调整种植结构的重要原因,然而,经过对新制度一年的适应后,农户对种植玉米的路径依赖、补贴错位、地租的不合理增长以及大豆、玉米相对价格不理想等问题逐渐凸显,2018年农户重新调整种植决策,补贴的激励作用被迫减弱.基于此,研究结论为统筹大豆、玉米补贴机制可以促进农户种植结构调整提供经验性证据,也为在农业供给侧结构性改革和大豆振兴压力下如何持续改善种植结构提供政策启示.     

Semiparametric Bayesian analysis for longitudinal mixed effects models with non-normal AR(1) errors

Statistics and Computing - This paper studies Bayesian inference on longitudinal mixed effects models with non-normal AR(1) errors. We model the nonparametric zero-mean noise in the autoregression...     

Fast and approximate exhaustive variable selection for generalised linear models with APES

We present APproximated Exhaustive Search (APES), which enables fast and approximated exhaustive variable selection in Generalised Linear Models (GLMs). While exhaustive variable selection remains as the gold standard in many model selection contexts, traditional exhaustive variable selection suffers from computational feasibility issues. More precisely, there is often a high cost associated with computing maximum likelihood estimates (MLE) for all subsets of GLMs. Efficient algorithms for exhaustive searches exist for linear models, most notably the leaps‐and‐bound algorithm and, more recently, the mixed integer optimisation (MIO) algorithm. The APES method learns from observational weights in a generalised linear regression super‐model and reformulates the GLM problem as a linear regression problem. In this way, APES can approximate a true exhaustive search in the original GLM space. Where exhaustive variable selection is not computationally feasible, we propose a best‐subset search, which also closely approximates a true exhaustive search. APES is made available in both as a standalone R package as well as part of the already existing mplot package.     

The Ecology of Activism: Professional Mobilization as a Spatial Process

This article develops an ecological theory that shifts the paradigm of professional mobilization from causes to relational spaces. It analyzes different species of activist professionals by locating them in an ecology of activism and examining how collective action emerges from their boundary work with the ecology's increasing density and consolidation. It empirically grounds the theory by explaining the political activism of Chinese lawyers in the early twenty‐first century and how it led to a government crackdown in 2015. Using interviews, online ethnography, and archival data collected from 2005 to 2017, the research demonstrates that Chinese lawyers’ political mobilization has experienced three stages: (1) vacancy and isolation (2000–2007), (2) spatial consolidation (2008–2011), and (3) boundary work (2011–2015). The study has implications for theories of social space and for understanding professional mobilization in authoritarian contexts and beyond.     

对实验哲学三个基本问题的质疑与辩护

实验哲学自兴起以来,科学哲学界对它的质疑和批评从未停止:质疑实验哲学方法的有效性,怀疑实验结论的可靠性,甚至否定实验哲学的学科独立性。针对这些质疑和责难,文章试图通过对实验哲学的学科定位,实验哲学方法本身和实验哲学研究领域进行批判性分析,展开对实验哲学的辩护。     

批判性重构:莱斯关于“人之存在方式”的研究

当今社会最重大的时代主题就是人之存在问题。莱斯是最早用马克思主义理论透视人之存在方式问题的生态学马克思主义者。对于人之存在方式的研究,莱斯有其独特的逻辑理路与研究范式。他准确预言了高集约度市场布局下人的异化存在已经由生产领域转向消费领域,并判明主体存在方式由理性控制走向非理性狡计的历史趋势。莱斯所描绘的生态社会主义蓝图看似极具浪漫主义的乌托邦情结,但他所开启的从生态学马克思主义视域探究人之存在方式问题的研究路向影响深远。