Application of Markov chain Monte Carlo methods to modelling birth prevalence of Down syndrome

Data collected before the routine application of prenatal screening are of unique value in estimating the natural live-birth prevalence of Down syndrome. However, much of these data are from births from over 20 years ago and they are of uncertain quality. In particular, they are subject to varying degrees of underascertainment. Published approaches have used ad hoc corrections to deal with this problem or have been restricted to data sets in which ascertainment is assumed to be complete. In this paper we adopt a Bayesian approach to modelling ascertainment and live-birth prevalence. We consider three prior specifications concerning ascertainment and compare predicted maternal-age-specific prevalence under these three different prior specifications. The computations are carried out by using Markov chain Monte Carlo methods in which model parameters and missing data are sampled.     

曲线箱梁桥实用设计方法的研究

曲线箱梁桥目前还缺乏比较实用的设计方法．本文对曲线箱梁桥的现有设计方法作了研究，并推荐一种实用设计方法：采用空间梁单元，每个节点取六个自由度；等效梁格的模拟考虑了横向梁格附近有无横隔梁的情况．结果证明，这是一种简便、较精确的设计方法．     

信息分析与预测产业化的法律环境分析

信息分析与预测产业化从产品商品化开始,这是一个庞大的系统工程。其商品化引发了一系列产业连带效应,促进其在服务方式、服务内容、管理体制等方面迅速与市场接轨,并整体向产业化进军。依据我国国情与国际惯例,必须吸收其它部门的立法经验与成果,建立整套完善的有中国特色的信息法律体系。     

战略成本管理方法体系探索

战略成本管理的思想是成本管理与战略管理有机结合的产物,是传统成本管理系统对竞争环境变化所做出的一种适应性变革,是当代成本管理发展的必然趋势。战略成本管理方法可以分为基本方法和具体方法,这些方法还可进行整合。     

Effects of Hourly,Low-Incentive,and High-Incentive Pay on Simulated Work Productivity: Initial Findings With a New Laboratory Method

The failures of previous studies to demonstrate productivity differences across different percentages of incentive pay may be partially due to insufficient simulation fidelity. The present study compared the effects of different percentages of incentive pay using a more advanced simulation method. Three payment methods were tested: hourly, low-incentive, and high-incentive (0%, 10%, and 100%) pay. Four participants performed a simulated work task for 30 6-hr sessions. Productivity under the 100% incentive condition was consistently higher than under the 10% condition for all participants. Productivity under the 10% condition was higher than under the 0% condition for two participants. Results suggest that different percentages of incentive pay may in fact produce productivity differences under more realistic simulated work conditions.     

论《左传》“天德合一”的天命观——《左传》预言的本质

本文认为,《左传》“多叙鬼神之事,预言祸福之期”现象的产生不是偶然的,而是尚未脱离神职的史官,或者说与宗教文化有千丝万缕联系的史官文化在探究天(神)人关系时的必然现象。《左传》既大讲鬼神对人的控制,又渲染道德决定人的归宿,本文通过对这一看似矛盾现象的系统分析认为,《左传》通过对鬼神预言结果的道德阐释,以高超的技巧将看似杂乱无章的神秘预言纳入到了一个“天德合一”的模式中,从而建构了一个天命控制人类历史,道德决定人的命运的完整的天命观体系;这种把天命神学纳入历史道德领域的努力,是《左传》作者为解释春秋战国之际的历史变迁而做的理论准备,这种试图以建构体系的方式阐释天人关系、历史规律的尝试也是值得肯定的。     

Designing and integrating composite networks for monitoring multivariate gaussian pollution fields

Networks of ambient monitoring stations are used to monitor environmental pollution fields such as those for acid rain and air pollution. Such stations provide regular measurements of pollutant concentrations. The networks are established for a variety of purposes at various times so often several stations measuring different subsets of pollutant concentrations can be found in compact geographical regions. The problem of statistically combining these disparate information sources into a single 'network' then arises. Capitalizing on the efficiencies so achieved can then lead to the secondary problem of extending this network. The subject of this paper is a set of 31 air pollution monitoring stations in southern Ontario. Each of these regularly measures a particular subset of ionic sulphate, sulphite, nitrite and ozone. However, this subset varies from station to station. For example only two stations measure all four. Some measure just one. We describe a Bayesian framework for integrating the measurements of these stations to yield a spatial predictive distribution for unmonitored sites and unmeasured concentrations at existing stations. Furthermore we show how this network can be extended by using an entropy maximization criterion. The methods assume that the multivariate response field being measured has a joint Gaussian distribution conditional on its mean and covariance function. A conjugate prior is used for these parameters, some of its hyperparameters being fitted empirically.     

1998年狮子座流星暴的一些预测

1998年狮子座流星暴是本年度最重要的天象之一。而广东省处于观测的最有利位置,为了不错过这次十分难得的机会,本文叙述了狮子座流量暴的本质及其观测工作的意义,求出了该流星暴母体的部分轨道根数;对1998年狮子座流星暴作了一些预测;对观测方法提出了一些建议,本次预测虽用的是天文专业的方法,但为了使更多的观测员理解,本文尽可能使用最基础的知识。     

移动技术教学之我见

本文对移动在篮球运动中的重要意义和作用,进行了深入的研究,对移动的教学方法进行了实践和总结。