Sequential, Bayesian Geostatistics: A Principled Method for Large Data Sets

The principled statistical application of Gaussian random field models used in geostatistics has historically been limited to data sets of a small size. This limitation is imposed by the requirement to store and invert the covariance matrix of all the samples to obtain a predictive distribution at unsampled locations, or to use likelihood-based covariance estimation. Various ad hoc approaches to solve this problem have been adopted, such as selecting a neighborhood region and/or a small number of observations to use in the kriging process, but these have no sound theoretical basis and it is unclear what information is being lost. In this article, we present a Bayesian method for estimating the posterior mean and covariance structures of a Gaussian random field using a sequential estimation algorithm. By imposing sparsity in a well-defined framework, the algorithm retains a subset of " basis vectors " that best represent the " true " posterior Gaussian random field model in the relative entropy sense. This allows a principled treatment of Gaussian random field models on very large data sets. The method is particularly appropriate when the Gaussian random field model is regarded as a latent variable model, which may be nonlinearly related to the observations. We show the application of the sequential, sparse Bayesian estimation in Gaussian random field models and discuss its merits and drawbacks.     

论抗美援朝战争的国内宣传工作

抗美援朝战争期间,我国对反对美国侵略、保卫和平及抗美援朝必要性进行了广泛宣传,后来随着形势发展转变为对支援抗美援朝战争和争取战争胜利进行的宣传。这一时期我国国内宣传工作的特点是:建立覆盖党内党外和城市乡村的宣传网;用社论和时评指导运动;赋予爱国主义具体、可行、人性的内涵。抗美援朝战争时期的国内宣传工作不仅进行了成功的经济建设动员和战争动员,也成功地诠释了民族精神和马克思主义思想意识,掀起了建国后第一次爱国主义高潮,不仅帮助中国取得了抗美援朝战争的伟大胜利,而且稳固了新政权,保证了各项社会改革、经济重建工作的顺利进行,极大地提高了民族自信心和凝聚力。     

Searching for Yiong Tibetan Knifes

Ten Hours＇ Road Travel for Only Fifty-Five Kilometers Staff from the Information Office of Pome County informed us that Yiong Town produced a special Tibetan knife. This kind of knife has beautiful color patterns zigzagging along the edge of the knife. Therefore, the knife is also referred to as the ＂rainbow knife＂. It is handmade in a tradition inherited from local ancestors several generations ago. It can be referred to as a Yiong specialty. Desiring to have a look, we decided to drive to Yiong. Although staff from the Information Office of Pome County tried several times to make a phone call via satellite, there was no response which meant no guide or interpreter to lead us, so we had to be selfsufficient. Nevertheless, the attraction of such a fascinating knife lured a team of photographers consisting of five persons to set off together to search for the rainbow knife.     

作为交往方式的七夕乞巧——广州市珠村乞巧节俗调查报告

在广州天河区的珠村一带的诸村落,乞巧节中“摆七娘”和“睇七娘”的传统源远流长。传统中的七夕乞巧为村落及宗族间姓氏的流动建构了媒介和文化空间,而它在现代的变迁实际上打破了区域社会内部的交往,使其通过文化展演的形式唤起群众的地方感,同时带有一种对商业回报的诉求。笔者于2007、2008年先后三次对珠村进行田野调查,较为全面地记录了传统与现代乞巧节的情况,并通过对这些田野资料进行初步分析,观照七夕乞巧活动中联村仪式的特性,以及其现代形态中新的文化内涵。     

Phytolith evidence for hearths and beds in the late Mousterian occupations of Esquilleu cave (Cantabria,Spain)

Esquilleu cave site has provided a moderately well preserved archaeological cave deposit from the Late Pleistocene in the Cantabrian area. Phytolith quantification, identification and determination of the refractive index have been carried out, together with FTIR analyses, from sediment samples collected in the profile. The comparison of the data obtained with the previous micromorphological results allows us to make inferences about the site formation processes and the Neanderthals use of the cave. Phytolith results show the presence of grass leaves nearby the hearth suggesting the repetitive existence of a bedding zone on the same area. Neanderthal behavioral patterns should be revised on the light of high resolution analyses, since diagenetic processes can obscure the existence of differentiated activity areas in the site.     

A MAZE OF TRANSPORTATION LINES IN TIBET

<正>In 2001,by chance I traveled along the road from Qinghai to Tibet. Though I did not experience the full length of this national road,I was very impressed by what I observed of Tibetan culture.Up to early 2007, I had entered Tibet eight times,from different directions through the four major access points:Sichuan,Yunnan,Xinjiang and Qinghai. Shouldering the responsibility of filming a documentary,I together with my colleagues in 2002 and 2004 drove a vehicle along the route from Sichuan to Tibet,but my third visit to Tibet was by myself.The route from Sichuan to Tibet     

变动中的家与地方:一个关联性的研究综述

家与地方的关系是地方性研究中的关键性命题。人本主义地理学认为地方根植是家的根本属性,批判地理学则从社会建构的角度阐释家与地方的动态关联。在全球化和灾害影响下,家与地方的联结方式不断变动,呈现出异常丰富的多样性。本文从理论脉络入手,对全球化进程中因绅士化引起的家的置换,无家可归与家在他乡,以及离散者的漂移之家等现象进行了分析;并从灾民自我调适行为和灾后重建计划的实施方面,讨论了灾害影响下家的重构与认同问题。相关学科和国际研究在这一领域的快速发展,将为国内社会文化地理学对家的探索创造良好的机遇。     

Stability of phytoliths in the archaeological record: a dissolution study of modern and fossil phytoliths

Opaline phytoliths are important microfossils used in archaeological and ecological research. Relatively little is known about the stability of phytoliths after burial. Under alkaline pH conditions they can dissolve, and mechanical disturbances can cause a loss of their more delicate appendages. Here we present an experimental study of phytolith stability (combination of solubility and abrasion). Modern and fossil phytoliths were extracted from wheat using new methods to minimize dissolution, and by burning in an oven. These assemblages were placed in a solution buffered to pH 10 and maintained under constant temperature and shaking conditions. The silicon concentrations in the solution were monitored once a week for 5 weeks. The phytolith morphologies in each assemblage were determined at the outset of the experiment and after 5 weeks. The results show that there are differences in stability between various assemblages. Modern inflorescence wheat phytolith assemblages are more unstable than those from leaves/stems. Burnt assemblages are less stable than unburnt assemblages, and a fossil phytolith assemblage about 3000 years old is more stable than the modern wheat assemblages. The results also show that individual phytolith morphotypes have different stabilities, and as a result of dissolution and abrasion, some morphotypes may resemble others. This study further shows that archaeological and/or paleo-environmental interpretation of phytolith assemblages may change with the assemblage’s state of preservation.