Quantifying uncertainty in the biospheric carbon flux for England and Wales

Summary.  A crucial issue in the current global warming debate is the effect of vegetation and soils on carbon dioxide (CO₂) concentrations in the atmosphere. Vegetation can extract CO₂ through photosynthesis, but respiration, decay of soil organic matter and disturbance effects such as fire return it to the atmosphere. The balance of these processes is the net carbon flux. To estimate the biospheric carbon flux for England and Wales, we address the statistical problem of inference for the sum of multiple outputs from a complex deterministic computer code whose input parameters are uncertain. The code is a process model which simulates the carbon dynamics of vegetation and soils, including the amount of carbon that is stored as a result of photosynthesis and the amount that is returned to the atmosphere through respiration. The aggregation of outputs corresponding to multiple sites and types of vegetation in a region gives an estimate of the total carbon flux for that region over a period of time. Expert prior opinions are elicited for marginal uncertainty about the relevant input parameters and for correlations of inputs between sites. A Gaussian process model is used to build emulators of the multiple code outputs and Bayesian uncertainty analysis is then used to propagate uncertainty in the input parameters through to uncertainty on the aggregated output. Numerical results are presented for England and Wales in the year 2000. It is estimated that vegetation and soils in England and Wales constituted a net sink of 7.55 Mt C (1 Mt C = 10¹² g of carbon) in 2000, with standard deviation 0.56 Mt C resulting from the sources of uncertainty that are considered.     

Interpreting DNA Mixtures with Related Contributors in Subdivided Populations

Abstract.  In this paper, we study the statistical interpretation of forensic DNA mixtures with related contributors in subdivided populations. Compact general formulae for match probabilities are obtained for two situations: a relative of one tested person is an unknown contributor of a DNA mixture; and two related unknowns are contributors. The effect of kinship and population structure is illustrated using a real case example.     

点击式合同的民事纠纷的管辖及其证据规则

点击式合同是在网络中应用的一种特殊的合同订立形式,由于其订立方式的特殊性,导致在其引起的民事纠纷处理上我国目前的管辖制度和证据规则难以适用,为了适应网络发展和新合同形式的需要,必须制定新的法律规则,以促进网络贸易的发展。     

Choice of the primary analysis in longitudinal clinical trials

Missing data, and the bias they can cause, are an almost ever‐present concern in clinical trials. The last observation carried forward (LOCF) approach has been frequently utilized to handle missing data in clinical trials, and is often specified in conjunction with analysis of variance (LOCF ANOVA) for the primary analysis. Considerable advances in statistical methodology, and in our ability to implement these methods, have been made in recent years. Likelihood‐based, mixed‐effects model approaches implemented under the missing at random (MAR) framework are now easy to implement, and are commonly used to analyse clinical trial data. Furthermore, such approaches are more robust to the biases from missing data, and provide better control of Type I and Type II errors than LOCF ANOVA. Empirical research and analytic proof have demonstrated that the behaviour of LOCF is uncertain, and in many situations it has not been conservative. Using LOCF as a composite measure of safety, tolerability and efficacy can lead to erroneous conclusions regarding the effectiveness of a drug. This approach also violates the fundamental basis of statistics as it involves testing an outcome that is not a physical parameter of the population, but rather a quantity that can be influenced by investigator behaviour, trial design, etc. Practice should shift away from using LOCF ANOVA as the primary analysis and focus on likelihood‐based, mixed‐effects model approaches developed under the MAR framework, with missing not at random methods used to assess robustness of the primary analysis. Copyright © 2004 John Wiley & Sons, Ltd.     

国外教师期望效应研究进展与当代教育启示

教师期望效应是教师对学生的期望在学生的未来发展中得到证实的现象,它反映了教师对学生的态度会影响学生发展的方向和程度,开展该现象的研究对教师观念的改变和学生的健康发展均有重要意义。对教师期望效应的种类、理论模型及国外的相关研究进行了介绍,探讨了其对教育现实的一些重要启示。     

新时期仍需坚持“效率优先,兼顾公平“的原则

改革开放以来 ,我国在分配制度上一直坚持“效率优先 ,兼顾公平”的原则 ,坚持这一原则 ,是社会主义本质的要求 ,是符合我国社会主义初级阶段国情的。世纪之初 ,在贯彻实施“十五”计划的新时期 ,我们仍需继续坚持这一分配原则。     

Creating a reference to a complex emergency situation using time series methods: war in Guinea-Bissau 1998-1999

Impacts of complex emergencies or relief interventions have often been evaluated by absolute mortality compared to international standardized mortality rates. A better evaluation would be to compare with local baseline mortality of the affected populations. A projection of population-based survival data into time of emergency or intervention based on information from before the emergency may create a local baseline reference. We find a log-transformed Gaussian time series model where standard errors of the estimated rates are included in the variance to have the best forecasting capacity. However, if time-at-risk during the forecasted period is known then forecasting might be done using a Poisson time series model with overdispersion. Whatever, the standard error of the estimated rates must be included in the variance of the model either in an additive form in a Gaussian model or in a multiplicative form by overdispersion in a Poisson model. Data on which the forecasting is based must be modelled carefully concerning not only calendar-time trends but also periods with excessive frequency of events (epidemics) and seasonal variations to eliminate residual autocorrelation and to make a proper reference for comparison, reflecting changes over time during the emergency. Hence, when modelled properly it is possible to predict a reference to an emergency-affected population based on local conditions. We predicted childhood mortality during the war in Guinea-Bissau 1998-1999. We found an increased mortality in the first half-year of the war and a mortality corresponding to the expected one in the last half-year of the war.     

成长的感悟——析青年作曲家张朝的《变奏曲》

从音乐形态、表现手法等方面具体分析《变奏曲》这部钢琴作品,探究其中对中国传统戏曲效果的模拟,以及作者如何巧妙地借鉴皮黄丰富的音响和表现力并运用到钢琴音乐中。中西的结合,古今的碰撞、鲜明的色彩个性,这些特点使得这部作品成为探索中国钢琴音乐民族化道路上的闪光点。     

文学思潮中的“花花公子”——简论“欲望化写作”

欲望化写作是当今文坛上方兴未艾的且引人注目的文学现象,其注重张扬感官放纵和感官感受。本文拟从欲望化写作的成因、分类以及欲望化写作的积极影响和消极影响等几个方面来探讨欲望化思潮。     

善意取得制度研究

善意取得制度意在对特定类型的非正常的利益变动,做出价值判断,进行利益衡平。那么,善意取得制度对何种类型非正常的利益变动进行衡平?又是如何进行衡平的呢?这就引出了善意取得制度的构成要件及其效力问题。笔者正是从这两方面着手对善意取得制度基础理论和实践应用提供一孔之见。