关于“吐蕃”一词的语源考证

我们拜读了牙含章同志在《民族研究》一九八○年第四期上发表的《关于“吐蕃”、“朵甘”、“乌斯藏”和西藏的语源考证》后,深受启发。牙含章同志通过丰富的汉藏历史语言资料,在深入研究以上问题的同时写道:“唐朝人在‘蕃’字前为什么又加了一个‘吐’字,到现在还弄不清楚。”我们根据突厥和维吾尔文献资料,对牙含章同志所提出的问题加以考证,并提出我们的一点浅见,以供研究藏族史的同志们参考。藏族人民自古以来把自己的族名称为“bod”或“bodba”。最早记录藏族情况的汉文《甥舅联盟碑》(又称《会盟碑》),公元823年立。后晋(公元936——946年)、宋代(公元960——1279年)成书的《新唐书》、《旧唐书》中“吐蕃”的‘蕃’字,     

A DIRICHLET PROCESS MIXTURE OF HIDDEN MARKOV MODELS FOR PROTEIN STRUCTURE PREDICTION

By providing new insights into the distribution of a protein's torsion angles, recent statistical models for this data have pointed the way to more efficient methods for protein structure prediction. Most current approaches have concentrated on bivariate models at a single sequence position. There is, however, considerable value in simultaneously modeling angle pairs at multiple sequence positions in a protein. One area of application for such models is in structure prediction for the highly variable loop and turn regions. Such modeling is difficult due to the fact that the number of known protein structures available to estimate these torsion angle distributions is typically small. Furthermore, the data is "sparse" in that not all proteins have angle pairs at each sequence position. We propose a new semiparametric model for the joint distributions of angle pairs at multiple sequence positions. Our model accommodates sparse data by leveraging known information about the behavior of protein secondary structure. We demonstrate our technique by predicting the torsion angles in a loop from the globin fold family. Our results show that a template-based approach can now be successfully extended to modeling the notoriously difficult loop and turn regions.     

A hybrid Newton-type method for censored survival data using double weights in linear models

As an alternative to the Cox model, the rank-based estimating method for censored survival data has been studied extensively since it was proposed by Tsiatis [Tsiatis AA (1990) Ann Stat 18:354–372] among others. Due to the discontinuity feature of the estimating function, a significant amount of work in the literature has been focused on numerical issues. In this article, we consider the computational aspects of a family of doubly weighted rank-based estimating functions. This family is rich enough to include both estimating functions of Tsiatis (1990) for the randomly observed data and of Nan et al. [Nan B, Yu M, Kalbfleisch JD (2006) Biometrika (to appear)] for the case-cohort data as special examples. The latter belongs to the biased sampling problems. We show that the doubly weighted rank-based discontinuous estimating functions are monotone, a property established for the randomly observed data in the literature, when the generalized Gehan-type weights are used. Though the estimating problem can be formulated to a linear programming problem as that for the randomly observed data, due to its easily uncontrollable large scale even for a moderate sample size, we instead propose a Newton-type iterated method to search for an approximate solution of the (system of) discontinuous monotone estimating equation(s). Simulation results provide a good demonstration of the proposed method. We also apply our method to a real data example.     

Comparing the Survival of Two Groups with an Intermediate Clinical Event

Consider a subject entered on a clinicaltrial in which the major endpoint is a time metric such as deathor time to reach a well defined event. During the observationalperiod the subject may experience an intermediate clinical event.The intermediate clinical event may induce a change in the survivaldistribution. We consider models for the one and two sample problem.The model for the one sample problem enables one to test if theoccurrence of the intermediate event changed the survival distribution.This models provides a way of carrying out non-randomized clinicaltrial to determine if a therapy has benefit. The two sample problemconsiders testing if the probability distributions, with andwithout an intermediate event, are the same. Statistical testsare derived using a semi-Markov or a time dependent mixture model.Simulation studies are carried out to compare these new procedureswith the log rank, stratified log rank and landmark tests. Thenew tests appear to have uniformly greater power than these competitortests. The methods are applied to a randomized clinical trialcarried out by the Aids Clinical Trial Group (ACTG) which comparedlow versus high doses of zidovudine (AZT).     

The business of education: a new paradigm

Business as usual is not the answer these days. But how do you create a new paradigm for academic educational and research endeavors? There is increasing pressure to separate the costs of providing care to patients from those of educating students and residents. It is evident already that we will not enjoy the flexibility of the past to cross-subsidize the academic effort. Presented here is a case study--a joint venture between Harvard Medical School and Beth Israel HealthCare created to sustain the academic mission, as distinct from its clinical business, and promote innovation in medical education and research through intellectual leadership, dedicated state-of-the-art facilities, and a focused development effort.     

突厥语族民族文化专题研究点评

突厥语民族是我国北方的主要民族群体,他们的语言属于阿尔泰语系突厥语族。目前,全世界有土耳其、阿塞拜疆、吉尔吉斯、乌兹别克、土库曼和哈卡斯等20多个突厥语民族,我国仅有维吾尔族、哈萨克族、柯尔克孜族、乌孜别克族、塔塔尔族、撒拉族、裕固族7个突厥语族民族,     

英藏呼图克图史实考

我们知道,在十六世纪末、十七世纪初西蒙古——卫拉特人历史上发生了举世瞩目的卫拉特人皈依藏传佛教格鲁派一事。自此,卫拉特部中就产生了一个新的阶层——僧人,并出现了一些名僧,如咱雅班第达等。在咱雅班第达返回故乡以前,卫拉特部宗教阶层中也产生过享有一定声望的僧人,例如英藏呼图克图就是。他在托忒文及藏文文献中除此称呼外,还被称为温萨活佛,在清代文献中也被写成“尹札胡土克图”和“尹咱胡图克图”。 在托忒文文献德迪的《蒙古根源史》中记载有:“著名的温萨呼图克图是佛祖生前大弟子的转吐佛”。但其中没有交待有关他转世的详细情况。而藏文文献《汉蒙藏史略》则弥     

中国税收政策作用的演化

一、改革进程中的预算发展国家预算起着巩固中央和地方政府财政运作的作用。1.税收的趋势1978年以前,企业将其全部剩余资金上缴财政,政府则承诺向企业提供投资资金和所需流动资金。为了提高效率,有必要允许企业自留部分利润用于投资和作为管理及劳动的奖金。因此在1978年,中     

他患胆结石的惨痛教训

他今年76岁,前些日子做了胆囊切除手术,经历了一次生死考验,现在已经恢复健康。他整个得病治病过程,实在是一份很好的教材。