Human reliability analysis: A critique and review for managers

In running our increasingly complex business systems, formal risk analyses and risk management techniques are becoming more important part to managers: all managers, not just those charged with risk management. It is also becoming apparent that human behaviour is often a root or significant contributing cause of system failure. This latter observation is not novel; for more than 30 years it has been recognised that the role of human operations in safety critical systems is so important that they should be explicitly modelled as part of the risk assessment of plant operations. This has led to the development of a range of methods under the general heading of human reliability analysis (HRA) to account for the effects of human error in risk and reliability analysis. The modelling approaches used in HRA, however, tend to be focussed on easily describable sequential, generally low-level tasks, which are not the main source of systemic errors. Moreover, they focus on errors rather than the effects of all forms of human behaviour. In this paper we review and discuss HRA methodologies, arguing that there is a need for considerable further research and development before they meet the needs of modern risk and reliability analyses and are able to provide managers with the guidance they need to manage complex systems safely. We provide some suggestions for how work in this area should develop. But above all we seek to make the management community fully aware of assumptions implicit in human reliability analysis and its limitations.     

Phytoremediating a copper mine soil with Brassica juncea L., compost and biochar

The soils at a depleted copper mine in Touro (Galicia, Spain) are chemically degraded. In order to determine the effect of amendments and vegetation on the chemical characteristics of a mine soil and on the plant uptake of metals, a greenhouse experiment was carried out for 3 months. A settling pond soil was amended with different percentages of a compost and biochar mixture and vegetated with Brassica juncea L. The results showed that the untreated settling pond soil was polluted by Cu. Amendments and planting mustards decreased the pseudototal concentration of this metal, reduced the extreme soil acidity and increased the soil concentrations of C and TN. Both treatments also decreased the CaCl₂-extractable Co, Cu and Ni concentrations. However, the amendments increased the pseudototal concentration of Zn in the soil, provided by the compost that was used. The results also showed that mustards extracted Ni efficiently from soils, suggesting that B. juncea L. is a good phytoextractor of Ni in mine soils.     

Maternity health care professionals' views and experiences of fetal genomic uncertainty: A review

The field of prenatal screening and diagnosis for fetal anomalies has been marked by a rapid succession of technological advances, including most notably, chromosomal microarray analysis, and next generation sequencing. Despite the diagnostic advantages of these technologies, their incorporation into prenatal testing has created additional challenges of revealing genomic variants of unknown or uncertain significance, and secondary findings. While detailed posttest counseling about uncertain variants is best performed by medical geneticists, many of the screening and diagnostic tests that lead to this information are actually ordered by general maternity health care professionals (HCPs), such as obstetricians, midwives, and family physicians. Maternity HCPs support pregnant women through to the conclusion of their pregnancy and the postpartum period, and thus are close observers of the psychosocial impart of fetal genomic uncertainty on women and their families. While there have been many studies exploring the handling of genomic uncertainty by genetics HCPs, there has been relatively less attention paid to maternity HCPs without speciality training in genetics. This review explores the current literature surrounding nongenetic maternity HCPs' views and experiences of genomic uncertainty and returning uncertain results in the prenatal setting.     

Mechanistic studies on the role of PAHs and related compounds in PCDD/F formation on model fly ashes

Model fly ashes containing Florisil, CuCl2.2H2O and PAHs with structures similar to dibenzo-p-dioxin or dibenzofuran were heated at 250 degrees C in He/O2 with regard to a supposed intramolecular reaction mechanism for oxygen incorporation. Highest reactivities in PCDF formation could be found for model compounds containing a biphenyl structure, while condensed pi-systems lead to a decrease in reactivity for such compounds. Biphenyl is almost completely converted to dibenzofuran. PCDD formation from six-membered rings like xanthene/9,10-dihydroanthracene is of minor importance. 18O-labeling of gaseous oxygen reveals no common reaction step for oxygen incorporation using 9-fluorenone, xanthene, diphenyl ether and diphenyl-2-carboxylic acid as model compounds. Pre-existing oxygen in reactants is a major source for ether groups in PCDD and PCDF. Determination of labeled and unlabeled CO and CO2 besides He/O2 reflects higher reactivities towards oxidation for model compounds containing ether groups than for compounds with carbonyl groups.     

A qualitative tool combining an interaction matrix and a GIS to map vulnerability to traffic induced air pollution

Local authorities and transport planners need fast and straightforward tools to perform their preliminary air quality assessments. Such tools are required to provide an initial impression of the local air quality and to highlight areas requiring a more rigorous investigation. This paper presents a technique to develop such a tool, for performing an initial assessment of air quality due to traffic in an urban area. The technique combines an interaction matrix methodology as developed for rock engineering systems, with Geographical Information System (GIS) map overlaying. This interaction matrix methodology incorporates a total system approach, which identifies the main parameters and quantifies the interactions between them. Weighting values for these parameters are obtained either through parametric studies, using numerical modelling, or from engineering judgement. These weightings are applied to spatial datasets for a study area using a GIS. The GIS results are presented in the form of a vulnerability map, which highlights the areas susceptible to poor air quality. This visual interpretation of the results is ideal for local authorities, who have to report to a wide range of non-specialists in the field, for example, planners, councillors and the public. The vulnerability map compares favourably with pollutant concentration patterns, obtained from an advanced dispersion model.     

罗斯比中心区域气候模型Ⅰ:对当前欧洲气候的气候学及性能模拟

描述了罗斯比中心区域气候模型(RCA2)并依据观测评估了其对整个欧洲当前气候的模拟结果.指出了模型平均气候和气候变率中的系统偏差,确定了关键参数化的缺欠.对一些近地面参数,尤其是温度、降水、地表能量收支和云量进行了较为详细的研究.模型模拟的最近的气候和变率与真实情况高度吻合.强调了地表辐射收支分量的补偿误差,这些偏差的基本原因追溯到云、降水和辐射参数化的相关方面.模型有过于频繁产生小量级降水的倾向,这直接影响到云-辐射相互作用和地表温度的模拟.在评估由分析的边界条件驱动的高分辨率RCM时,对观测结果的使用要非常小心.当考虑到降水和云量时更是如此,因为观测的不确定性经常大于RCM的偏差.     

罗斯比中心区域气候模型Ⅱ:北极圈气候的应用

作为ARCMIP国际计划的一部分,罗斯比中心区域气候模型(RCA2)针对整个北冰洋地区的气候作了数值模拟整合,并与来自sHEBA数据集的观测资料作了比较,RCA2标准模型对北极冬季的云量和长波辐射的模拟较实况偏多.通过引入新的云量参数化方案(该参数化方案显著地改进了云量的年循环)减少了这部分误差,确定了介于晴空向下大气长波辐射与云层底部的长波辐射的补偿率,利用可以更准确描述冰晶与太阳辐射相互作用的辐射方案修正了模型,从而使得模型对云-太阳辐射间的相互作用的描述更接近实际.在模拟晴空辐射部分,由于太阳辐射大气透射率过大,经常在边界层云的顶部产生正偏差.引入真实海冰和积雪两种表面反照率的时间变化,对准确模拟地面能量净收支是至关重要的.同样,为了准确模拟北极圈地区近地面的热力学过程,将雪面温度作为预报量引入模型中也似乎是必不可少的.     

浮游植物和水质表征:从瑞典梅拉伦、哈马伦、韦特恩和维纳恩湖等大湖泊中获得的经验

自20世纪60年代以来,瑞典梅拉伦湖、哈马伦湖、韦特恩湖和维纳恩湖等大湖泊的浮游植物和环境变量一直处于监测之下.20世纪70年代政府出台了一些减少磷和工业废品排放的措施,于是水体磷的含量降低了90%～95%,结果大多数污染湖盆磷的浓度减少了一半.体现在浮游植物群落的变化是夏季蓝藻细菌、春季硅藻和隐鞭毛藻的生物量迅速降低,另一个反应是藻华期变短,生长季节的物种丰富度和生物量均匀度增加,浮游植物群落内物种数量和组成发生变化.此外,大湖泊物种丰富度相应与湖泊的特征有关.本文对湖泊中有毒蓝藻细菌的发生作了介绍,结合哈马伦湖和梅拉伦湖的藻华,确定在13～0.1 μg/L之间的微藻素最大和最小值;给出利用浮游植物作为监测指标确定水质量变化的基本框架,并提出了评价标准.