新疆古墓沟墓地人骨的稳定同位素分析——早期罗布泊先民饮食结构初探

本文应用稳定同位素分析技术对新疆罗布泊古墓沟墓地出土人骨中的C、N同位素比值进行了测定。结果显示：古墓沟早期青铜时代居民日常饮食习惯中保持着较大比例的肉类食物摄入,牛、羊肉是当时居民最为普遍的肉食来源,植物类食物的摄入中以C3类植物为主,很可能来源于小麦。这一研究结果涉及了距今3800年罗布泊地区的生态环境、罗布泊早期先民的社会经济生活及其饮食结构。同时对于深入研究新疆地区早期农业资源的利用与开发,也有着重要的意义。     

Inference for Continuous Semimartingales Observed at High Frequency

The econometric literature of high frequency data often relies on moment estimators which are derived from assuming local constancy of volatility and related quantities. We here study this local‐constancy approximation as a general approach to estimation in such data. We show that the technique yields asymptotic properties (consistency, normality) that are correct subject to an ex post adjustment involving asymptotic likelihood ratios. These adjustments are derived and documented. Several examples of estimation are provided: powers of volatility, leverage effect, and integrated betas. The first order approximations based on local constancy can be over the period of one observation or over blocks of successive observations. It has the advantage of gaining in transparency in defining and analyzing estimators. The theory relies heavily on the interplay between stable convergence and measure change, and on asymptotic expansions for martingales.     

我国宏观经济形势特点及政策分析

当前,我国经济正面临着宏观经济政策调整和经济发展方式转变的“双重转型”形势。国家经济政策的重点是稳增长,即努力寻求一个扩张政策和收紧政策之间的平衡点,尽早结束经济回调的过程。在复杂的形势下,国家正在进行稳增长政策的预调微调,整个经济增长止跌趋稳的迹象越来越明显。未来,我国要更多地着眼于经济转型,通过贯彻破产制度和理顺市场定价机制、加强债务管理、风险防范等制度调整和政策改革来加快经济转型,使我国经济进入新的发展态势。     

考虑稳定匹配条件的双边满意匹配决策方法

双边匹配问题是指如何在两个不相交的主体集合中依据各主体针对潜在匹配对象给出的偏好信息来确定合适的匹配结果,其在经济管理领域中存在着大量的实际背景,是许多学者关注的研究课题。在本文中,针对双边主体给出偏好序值信息的双边匹配问题,给出了一种考虑稳定匹配条件的双边满意匹配决策方法。首先给出了双边匹配、稳定匹配和满意匹配的相关概念;然后考虑到稳定匹配条件,并以双边主体满意度最大为目标,构建了多目标双边匹配优化模型;进一步地,采用线性加权法将多目标优化模型转换为单目标优化模型,并通过求解优化模型来获得最优匹配结果。最后,通过一个算例说明了本文提出方法的实用性和有效性。     

SUBSAMPLING THE JOHANSEN TEST WITH STABLE INNOVATIONS

By taking into account the thick-tail property of the errors, cointegration analysis in vector error-correction models with infinite-variance stable errors is a natural generalization of cointegration analysis in error-correction models with normally distributed errors. We study the Johansen test for cointegrated systems under symmetric stable innovations with discrete spectral measures. The results show that the distributions of the Johansen test statistics under these innovations involve nuisance parameters. To overcome the problem of nuisance parameters, we implement a nonparametric subsampling procedure. We document some subsampling simulation results and demonstrate in an empirical example how the test can be used in practice.     

HIGH-DIMENSIONAL PARAMETRIC MODELLING OF MULTIVARIATE EXTREME EVENTS

Multivariate extreme events are typically modelled using multivariate extreme value distributions. Unfortunately, there exists no finite parametrization for the class of multivariate extreme value distributions. One common approach is to model extreme events using some flexible parametric subclass. This approach has been limited to only two or three dimensions, primarily because suitably flexible high-dimensional parametric models have prohibitively complex density functions. We present an approach that allows a number of popular flexible models to be used in arbitrarily high dimensions. The approach easily handles missing and censored data, and can be employed when modelling componentwise maxima and multivariate threshold exceedances. The approach is based on a representation using conditionally independent marginal components, conditioning on positive stable random variables. We use Bayesian inference, where the conditioning variables are treated as auxiliary variables within Markov chain Monte Carlo simulations. We demonstrate these methods with an application to sea-levels, using data collected at 10 sites on the east coast of England.     

论实现社会从稳定到有序的战略抉择

新世纪伊始,我国已进入了社会矛盾的高发期。而当前深不见底的国际金融风暴和经济危机的影响,也必将使我国出现比较严重的失业、贫困、犯罪等社会问题,对社会稳定构成严峻挑战。在当前的形势下,从战略上解决社会稳定问题的意义重大、影响深远。社会保障的有效程度、社会团结程度、民主成熟度、劳动就业水平、收入差距扩大的社会容忍程度、社会结构状况、政府公信力、反腐败斗争的成效等,已经成为影响和决定我国社会稳定有序协调发展的基本要素。从构建有序社会的全局需要出发,研究社会稳定发展战略问题,通过加强和改进社会管理化解影响社会稳定的诸多因素,有针对性地采取治理和疏导政策,是积极应对社会风险的冲击,促进社会稳定有序协调发展的理性选择。     

地缘视角下新疆稳定发展的多元因素分析

影响新疆稳定发展的因素较多,包括政治、经济、体制等多方面的因素。该文从民族学的角度对影响新疆稳定的区位、民族、宗教、文化等因素进行分析,剖析利弊,并提出了相应的对策,即在上海合作组织的框架下,促进跨界民族"和平跨居",加强"四个认同"的宣传教育,提升民族凝聚力,坚决打击"三股势力",以期为新疆经济发展提供稳定的环境。     

Analysis of autoregressive models with symmetric stable innovations

This paper develops algorithms for fitting autoregressive models with symmetric stable innovations using auto-covariation function. A recursive algorithm is proposed for generalized Yule-Walker estimation of autoregressive coefficients and partial auto-covariation function. It also introduces a new information criterion, useful for consistent order selection. Applications of the proposed methods are illustrated using observations simulated from autoregressive models with symmetric stable innovations as well as by analysing a set of real data.     

缩减人口还是稳定人口?————中国向何处去的命运之择

对“控制人口数量”基本国策的实现程度有基本完成和远未完成两种判定。主张稳定人口的基本完成论以人口过快增长得到有效遏制作依据,并为“人口-环境均衡论”、“零增长-可持续人口论”、“常量人口-压力消失论”和“人口冬天论”所支持。远未完成论则坚持将缩减人口作为中国新的人口发展战略:持续性的症结是规模而非均衡,一个能为土地生产力支持的人口并不一定能保证与环境均衡的持续,存在着间断;人口规模问题不存在技术、经济和制度解,老龄化并非衰亡,人口压力远未消失;体现人少优势、具有“釜底抽薪”作用的小规模人口将从根本上改变“人口多、底子北的基本国情,保障粮食安全,增加选择机会和维护发展的可持续性;而维持一个15亿的稳定人口,必将使我们陷入“规模泥潭”而断送中华民族的未来。