The life table and competing risks

The concept of the life table originated in longevity studies of man, where it was always presented as a subject peculiar to public health, demography, and actuarial science. As a result, its development has not received sufficient attention in the field of statistics. Actually, the problems of mortality studies are similar to those of reliability theory and life testing, and they may be described in terms familiar to the statistically oriented mind. From a statistical point of view, human life is a random experiment and its outcome, survival or death, ss subject to chance. The life table systematically records the outcomes of many such experiments for a large number of individuals over a period of time. Thus, the quantities in the table are random variables subject to established statistical analysis. The purpose of this presentation is to discuss the life table from a statistical viewpoint.     

An overview of cross-sectional studies of mortality and air pollution and related statistical issues

A heuristic framework is developed for assessing statistical studies of air pollution and mortality which use the General Linear Model as a principal tool for analysis. Arrays that systematically compare the information of each study are introduced. In addition, a number of studies are contrasted against several statistical criteria to assess the reliability of the study results. Reliability is considered in terms of statistical estimation theory and practice. Finally, there is a discussion of several points of statistical contention which can affect the results of these studies. The conclusion is that statistical studies that use the General Linear Model have made limited use of available methods and tests. Several issues are raised which will require additional research.     

环境健康价值评估中的年龄效应研究

在环境健康价值评估研究中,统计寿命价值和年龄之间的关系是理论和实证研究焦点之一,也是重要的学术问题。长久以来,环境政策效益评估中是否应该赋予老年人较低的统计寿命价值一直存在广泛争议,且尚未得到一致性结论。通过设计选择实验,对北京市空气质量改善的健康效益进行了抽样调查,并采用MNL模型对北京市约500个居民的调查数据进行回归分析,估算了不同年龄人群对健康风险减少的支付意愿,针对中国人群中统计寿命价值和年龄之间的关系进行实证探讨。结果表明:一方面,在总体样本中设置年龄虚拟变量,回归结果表明年龄变量系数的符号均显著为负,即年龄因素对减少空气污染带来的死亡风险降低的支付意愿具有显著的影响,年龄越大支付意愿相对越小;另一方面,不同年龄人群分组样本结果显示,统计寿命价值与年龄之间呈现"倒U型"关系,统计寿命价值在中国存在"老年折扣"现象。研究结果可为我国环境政策的健康效益分析中如何考虑年龄的影响提供重要依据。     

Life cycle assessments of municipal solid waste management systems: A comparative analysis of selected peer-reviewed literature

Life cycle assessment (LCA) is a popular tool used to evaluate the environmental performance of municipal solid waste (MSW) management systems. Although reviews of LCAs of MSW have been undertaken to assess the validity of the ‘waste hierarchy,’ a recent review of the goal, scope and results of LCAs of mixed-material MSW management systems has yet to be performed. This paper is a comparative analysis of 20 process-based LCAs of MSW published between 2002 and 2008 in a total of 11 English-language peer-reviewed journals. It quantifies the methodological transparency of the studies and the frequency of use of particular system boundaries, types of data sources, environmental impact categories, impact weightings, economic valuations, sensitivity analyses, and LCA computer models. Net energy use (NEU), global warming potential (GWP), and acidification potential (AP) values for various types of MSW management systems are also compared using statistical indicators.The reviewed LCAs differ substantially in their system boundaries. Half or more of the LCAs either do not mention or are unclear in whether or not life cycle emissions from energy inputs or capital equipment are included in the calculation of results. Only four impact categories are common to more than half of the reviewed LCAs. The human and ecological toxicity impact categories are much less common than global warming potential, acidification, and eutrophication.A financial life cycle costing is present in eight of the reviewed LCAs, while an economic valuation of the environmental impacts is observed in five. Explicit sensitivity analyses are present in 4/20 of the studies, although many more LCAs evaluate the effects of varying model parameters by increasing the number of waste management scenarios. There is no consensus on whether or not to use the marginal or average source of electricity in calculating environmental impacts. Eight out of the 20 do not mention this source while the remaining LCAs are evenly split between the marginal and average electricity source. One quarter of the reviewed LCAs supply weighted results for the overall environmental performance of MSW management scenarios. All but one of these concurred with the ‘hierarchy of waste’ that the environmental performance of landfilling is lower than that of all the other treatment methods, and that thermal treatments are inferior to recycling.The comparative analyses of the NEU, GWP and AP results are based on 37, 45, and 42 MSW management scenarios, respectively. As measures of statistical dispersion, the interquartile ranges of the NEU, GWP and AP values are lowest for the landfilling (AP, NEU) and thermal treatment (GWP) scenarios. The results of the statistical analysis of the NEU, AP and GWP values appear to indicate that thermal treatment scenarios have a better environmental performance than landfilling, while the results for mixed treatment scenarios are less obvious. A comparison of the relative environmental performances of MSW treatment scenario types within each study did not provide a clear confirmation or repudiation of the waste hierarchy.This paper concludes that many recently published LCAs do not ensure that the methodological assumptions are made clear to the reader. Lack of transparency makes the results difficult to interpret, and hampers meaningful comparisons between the LCA results. A convergence in the adoption of particular assumptions that are more representative of MSW management systems would facilitate the comparison of the results.     

Psychological and sociological approaches to study risk perception

Technological progress and its impacts on humankind has caused an increasing awareness of risk, and objective, statistical estimations are often inadequate to alleviate the public's fright and fear. Research on risk perception using psychological and sociological approaches is trying to bridge this gap. As a first step, a distinction must be made between the technical definition of risk (probability X consequences) and the social definition, in which additional parameters (source, dimensions, timeframe, exposure) need to be included. The methodology of risk assessment, though objective by design, is limited in the interpretability of its results, if the calculation of consequences does not take public perceptions and social effects into account. The problems and advantages of risk assessment are discussed, and the key question for risk perception research are presented. Various techniques are available to study risk perception and attitudes towards risk; selection of a specific technique is determined by the objective of the research, namely sociological implications or psychological cognitions. Several empirical studies in both areas are presented and the results discussed.     

A quantitative estimate of nonsmokers' lung cancer risk from passive smoking

This work presents a quantitative assessment of nonsmokers' risk of lung cancer from passive smoking. The estimates given should be viewed as preliminary and subject to change as improved research becomes available. It is estimated that U.S. nonsmokers are exposed to from 0 to 14 mg of tobacco tar per day, and that the typical nonsmoker is exposed to 1.4 mg per day. A phenomenological exposure-response relationship is derived, yielding 5 lung cancer deaths per year per 100,000 persons exposed, per mg daily tar exposure. This relationship yields lung cancer mortality rates and mortality ratios for a U.S. cohort which are consistent to within 5% with the results of both of the large prospective epidemiological studies of passive smoking and lung cancer in the United States and Japan. Aggregate exposure to ambient tobacco smoke is estimated to produce about 5000 lung cancer deaths per year in U.S. nonsmokers aged ≥ 35 yr, with an average loss of life expectancy of 17 ± 9 yr per fatality. The estimated risk to the most-exposed passive smokers appears to be comparable to that from pipe and cigar smoking. Mortality from passive smoking is estimated to be about two orders of magnitude higher than that estimated for carcinogens currently regulated as hazardous air pollutants under the federal Clean Air Act.     

地块尺度耕地质量评价与方法探讨--以湖南省浏阳市为例

耕地是从事农作物种植的土地,为一个复杂的生态经济系统。影响耕地质量的主要因素通常有自然因素、社会经济因素和区位因素等,通过耕地质量影响因子的分析并建立衡量耕地质量变化的指标体系,对耕地逆转趋势的早期预警与耕地质量问题的及时发现,是非常必要的。从耕地质量状态、利用效率和耕地压力3个方面入手,运用SPSS软件对影响湖南省浏阳市耕地肥力的众多因素因子进行了取舍,并综合考虑地块区位、交通条件等状态因素,建立了耕地质量状态的评价指标体系,同时结合地块上作物的投入-产出效率和来自外界环境的耕地质量压力建立了基于地块尺度上的县级耕地质量评价体系,与此同时,对各指标因子的选取与量化进行了较系统的阐述,并以湖南省浏阳市作为研究对象进行了实证分析。     

On the defensive behavior of the grass snake <Emphasis Type="Italic">Natrix natrix</Emphasis> (Linnaeus, 1758)

Demonstrative imitations in the defensive behavior of grass snakes (Natrix natrix) captured in the Galich’ya Gora Reserve (70 ind.) and Kulikovskii Forestry (13 ind.), Lipetsk oblast, have been analyzed using statistical methods. The results suggest that grass snakes can play dead and imitate a venomous snake independently of their sex, age, and experience in receiving injuries. At the same time, there is evidence that such an ability is a hereditary trait subject to natural selection.     

Statistical downscaling for climate change projections in the Mediterranean region: methods and results

Besides dynamical downscaling by regional climate models, statistical downscaling (SD) is a major tool to derive climate change projections on regional or even local scales. For the Mediterranean area, an increasing number of downscaling studies based on different statistical techniques have been published in the last two decades with a broad range of sometimes differing results relating to different variables and regional domains. This paper gives a short review of these Mediterranean downscaling studies mainly considering the following two aspects: (1) what kind of progress has been realized in this field since the early 1990s? The review addresses the inclusion of extremes in downscaling assessments, the development of probabilistic approaches, the extension of predictor sets, the use of ensembles for both dynamical model simulations and statistical model assessments, the consideration of non-stationarities in the predictor–predictand relationships, and some advances related to synoptic downscaling. (2) What are the main regional climate change signals in the Mediterranean area, considering agreed and controversial points also with respect to dynamical models? Best accordance among future projections can be found in seasonal temperatures with lower rates of warming in winter and spring, and, in most cases, higher ones in summer and autumn. Different results are obtained for the intra-annual range of extreme temperatures, but high-temperature conditions are generally expected to increase. Regarding seasonal precipitation, predominant reductions are indicated for spring, summer, and autumn. For winter, however, projections are distinctly different (GCMs: rainfall decrease; RCMs: increase only in the northernmost parts of the Mediterranean region; SD: widespread increases in the northern and western parts in several studies). Different results are obtained for rainfall extremes, but the entire precipitation distribution tends to shift towards higher and lower values. Apart from some sub-regional deviations, there is a predominant increase in future dry period durations. For near-surface winds, only a few studies are available, and they project some decline mainly for the winter season.     

家庭生命周期对农户农地转出行为的影响研究——基于秦巴山区农户调查数据的实证分析

根据家庭生命周期理论内涵与外延，利用秦巴山区456户微观样本，运用统计分析法和Heckman两阶段模型，分析家庭生命周期对农户农地转出行为的影响。研究发现：家庭生命周期对农户农地转出行为有显著影响；处于不同家庭生命周期阶段的农户农地转出行为的影响因素存在差异。从人力资本来看，良好的劳动力健康状况不利于赡养期家庭参与农地转出，非农就业率对抚养期、负担期家庭参与农地转出有显著正向影响；从农户认知来看，限制农地用途，了解流入方，村委会推动、政府主导型转出均在不同程度上增加各阶段农户转出农地的可能性；对于拥有较多非农就业机会的抚养期和负担期家庭而言，农地确权通过强化地权稳定性促使其转出农地并外出务工。因此，在实践中执行农地流转政策时，应采取精准的农地转出激励措施，差别化对待不同生命周期的家庭。     

GIS技术在三峡库区滑坡灾害研究中的应用

对三峡库区选定的研究区域,建立地质、地形等滑坡因子空间数据库和滑坡空间分布数据库（比例尺均为1：10 000）,利用GIS技术对滑坡和各影响因子相关性进行了统计分析。计算得出滑坡发生的主要影响因子类属：Q\-4、J\-1x, J\-1z、S岩性岩组;90 m以下、90~135 m和135~175 m三个高程带;15~20m局部高差;10°~15°、15°~20°和20°~25°坡度;北向、南向和西北向方向和 1～1曲率范围。研究的结果是进行滑坡易发性评价的基础,可以帮助指导库区滑坡灾害管理、土地利用等。     

First steps towards a European atlas of natural radiation: status of the European indoor radon map

Within the context of its institutional scientific support to the European Commission, in 2005 the Radioactivity Environmental Monitoring (REM) group at the Joint Research Centre of the European Commission, started to explore the possibility of mapping indoor radon in European houses as a first step towards preparing a European Atlas of Natural Radiations. The main objective of such an atlas is to contribute to familiarizing the public with its naturally radioactive environment. The process of preparing the atlas should also provide the scientific community with a database of information that can be used for further studies and for highlighting regions with elevated levels of natural radiation. This document presents the status of the European indoor radon (Rn) map, first statistical results, and outlines of forthcoming challenges.     

Factors influencing the quality of rural human settlements in a peripheral metropolitan area based on a structural equation model: A case study from Beijing

Rural human settlement is a significant indicator of the living standards of rural residents, and its improvement can contribute to promoting the positive interaction between inhabited environment and the social, economic, and resource environment in the countryside. Based on 557 valid questionnaires of satisfaction evaluation of human settlement in the peripheral metropolitan area of Beijing, this paper analyzed the elemental characteristics and factors influencing human settlement quality using multivariate statistical analysis and a structural equation model. The result shows that, first, the rural residents in a peripheral metropolitan area of Beijing are generally satisfied with the quality of human settlement (satisfaction rate is 66.2%). Specifically, the natural and social environment of the countryside is excellent and harmonious and corresponding standard of countryside infrastructure is advanced, but the quality of public services and follow-up management of facilities are in urgent need of improvement and the imbalance between revenue and expenditure of rural households has led to a continuous increase in the pressures of life. Second, factors such as social atmosphere, appearance of the village, entertainment, living costs, fundamental public services, and production costs have significant effects on human settlement quality in this peripheral metropolitan area, with social atmosphere as the main one. Living costs and supporting services are the main constraints to improvement in the quality of human settlement.     

Climate change and natural disasters: macroeconomic performance and distributional impacts

Commonly occurring natural events become natural disasters when they affect the population through death and injury, and/or through the destruction of natural and physical capital on which people rely for their livelihood and quality of life. Climate change plays a role in that it tends to increase the frequency and intensity of weather-related natural disasters. Additionally, climate change may put people at risk by influencing access to water, coastal flooding, disease and hunger, and leaving them with a more degraded environment, leading, in turn, to increased vulnerability. The purpose of this paper is to present a review and synthesis of the literature and case studies addressing differential impacts of climate change-related natural disasters on a society and its economy. Developed and developing countries show different vulnerabilities to natural disasters. Even within countries, impacts vary significantly across population and economic sectors. When losses from natural disasters are large, their cumulative effect can have notable macroeconomic impacts, which feed back to further pronounce existing income inequalities and lower income levels. Impacts tend to be most pronounced for women, the young and elderly, and people of ethnic or racial minorities.

基于变更平衡表的土地利用演化信息提取与预测方法研究——以苏州市为例

变更平衡表为国土资源管理部门历年实地调查、汇总所得,精度高,目前的研究中对其深入的应用较少,基于变更平衡表的应用方法研究可为区域土地利用演变信息提取与预测提供帮助。推导了由连续年份的年度变更平衡表求多年周期的平衡表的方法,提出了基于土地利用综合动态度分析土地利用有序程度的思路,探讨了利用连续年份的变更平衡表预测任意年份土地利用结构的方法,并基于传统方法进行了改进,提出了利用矩阵开方法求预测概率矩阵。应用苏州市一定时期的连续年份的年度变更平衡表对上述方法进行了验证,结果表明:提出的信息提取方法有效,预测结果可信;在分析期内(1998~2008年),苏州市耕地大量减少的去向是各类建设用地增加的来源,区域土地利用有序程度较高;预测显示至2020年土地利用结构变化仍将维持农用地、耕地不断减少和建设用地总量不断增加的趋势,但转化的速率将有所放缓;对变更平衡表的深入应用有一定的借鉴意义。     

Lean framework for planning redesign proposals to optimise EOL environmental behaviour in WEEE products

The aim of this research was to define a sequence of actions to guide redesign propositions for electrical and electronic equipment products, which minimise negative consequences to the environment after the end of their useful life. Current practices mainly encourage the examination of individual problems as disassembly process and identification of suitable product end-of-life (EOL) treatment strategies. There also exist previous studies that try to incorporate EOL concerns in product design phase. In most cases, the main problem is the limited available EOL information because of its delayed retrieval. The proposed method focuses primarily on minimising this problem. The steps of the analysis performed include the selection of the optimal EOL treatment strategy and, afterwards, the evaluation of its results concerning the environment. In parallel, product design characteristics are grouped and examined concerning their expected significance for the environment in the EOL stage. The results from the previous stages are combined and product improvement actions are proposed for further examination in the redesign stage. The general framework used to conduct all these actions is lean thinking methodology. In the end, results concerning the application of the proposed method on a distribution transformer are presented.     

Vulnerability assessment within climate change and natural hazard contexts: revealing gaps and synergies through coastal applications

The climate change and natural hazard communities have developed the notion of vulnerability and associated methods for its assessment in parallel, with only limited interaction. What are the underlying reasons for this diversity; is there advantage in greater synergy? If yes, what are the pathways through which greater integration could be fostered? This paper discusses these issues using vulnerability studies in coastal areas to describe gaps between climate change and natural hazard approaches, and investigates scope for mutual learning and collaboration in the development of methodologies for vulnerability assessment. An overview of methods highlights the separation between climate change and natural hazard approaches. The main differences identified, beyond formal divergences in terminology, are linked to: process (stress vs shock), scale (temporal, functional and spatial), assessment approach (statistical vs prospective) and levels of uncertainty. We argue that the underlying source of divergence is the initial difference of purpose, one being identification of climate change adaptation pathways, the other being disaster risk reduction. In this context, the notion of vulnerability and its expression through assessment studies is the focal point connecting both domains. Indeed, the ongoing and active development of vulnerability concepts and methods have already produced some tools to help overcome common issues, such as acting in a context of high uncertainties, taking into account the dynamics and spatial scale of a social-ecological system, or gathering viewpoints from different sciences to combine human and impact-based approaches. Based on this assessment, this paper proposes concrete perspectives and possibilities to benefit from existing commonalities in the construction and application of assessment tools.     

The relationship between study sponsorship,risks of bias,and research outcomes in atrazine exposure studies conducted in non-human animals: Systematic review and meta-analysis

BackgroundA critical component of systematic review methodology is the assessment of the risks of bias of studies that are included in the review. There is controversy about whether funding source should be included in a risk of bias assessment of animal toxicology studies.ObjectiveTo determine whether industry research sponsorship is associated with methodological biases, the results, or conclusions of animal studies examining the effect of exposure to atrazine on reproductive or developmental outcomes.MethodsWe searched multiple electronic databases and the reference lists of relevant articles to identify original research studies examining the effect of any dose of atrazine exposure at any life stage on reproduction or development in non-human animals. We compared methodological risks of bias, the conclusions of the studies, the statistical significance of the findings, and the magnitude of effect estimates between industry sponsored and non-industry sponsored studies.ResultsFifty-one studies met the inclusion criteria. There were no differences in methodological risks of bias in industry versus non-industry sponsored studies. 39 studies tested environmentally relevant concentrations of atrazine (11 industry sponsored, 24 non-industry sponsored, 4 with no funding disclosures). Non-industry sponsored studies (12/24, 50.0%) were more likely to conclude that atrazine was harmful compared to industry sponsored studies (2/11, 18.1%) (p value = 0.07). A higher proportion of non-industry sponsored studies reported statistically significant harmful effects (8/24, 33.3%) compared to industry-sponsored studies (1/11; 9.1%) (p value = 0.13). The association of industry sponsorship with decreased effect sizes for harm outcomes was inconclusive.ConclusionOur findings support the inclusion of research sponsorship as a risk of bias criterion in tools used to assess risks of bias in animal studies for systematic reviews. The reporting of other empirically based risk of bias criteria for animal studies, such as blinded outcome assessment, randomization, and all animals included in analyses, needs to improve to facilitate the assessment of studies for systematic reviews.     

一种基于代表性样点的钉螺密度抽样调查设计方法

抽样设计是钉螺调查的关键环节，直接影响到统计推断的总体精度。目前湖沼型血吸虫病流行区钉螺调查常用的系统抽样设计方法存在样本量大、代表性不强、抽样效率不高等问题。通过对与钉螺空间分布上具有协同变化的环境因子进行模糊聚类分析，寻找可代表钉螺空间分布的代表性样点，提出一种基于代表性样点的抽样设计方法。将本研究设计的方法应用于鄱阳湖区恒湖农场茶叶港草洲的钉螺抽样设计研究，对采集的代表性样点进行误差分析，并将抽样结果与简单随机抽样和系统抽样方法进行精度比较。结果显示：本研究提出的“基于代表性样点的钉螺抽样设计方法（SORS）”明显优于简单随机抽样和系统抽样，抽样绝对误差分别为：0.440 7、1.551 4、3.565 3，相对误差分别为：1.048 1、3.689 7、8.479 6。本研究表明新方法能够获得比现有血防部门的钉螺调查方法更高的估算精度，可为优化湖沼型血吸虫病流行区钉螺调查方法提供借鉴。 关键词： 模糊聚类；抽样设计；代表性样点；钉螺