A modified computer hazard and operability study procedure

The application of modifications of the hazard and operability study method (Hazop) to process facilities using computer-based control systems has led to the development of computer Hazop (Chazop) procedures. A number of the Chazop procedures cited in the literature broaden the method and depart from the base documentation of the Hazop method. It is suggested that a robust Chazop method requires implementation at the line-by-line level of detail and as a separate, complementary study using the same base documentation (piping and instrumentation diagrams) as that used in the Hazop method.     

农业经营规模化发展对环境效率的影响——基于地块层面的实证分析

为探析农业规模化经营与农业环境可持续性之间的关系,对农业经营规模对农业环境效率的影响进行理论分析,并在此基础上构建了物料平衡原则下农业环境效率测算模型和农业环境效率影响模型.基于2004~2016年浙江省农户水稻种植地块层面的面板数据,实证检验了土地面积、劳动投入、资本投入和农业产出等农业经营规模指标对农业环境效率的影响.结果显示,农业规模化发展将因投入和产出的扩张以多种方式影响其环境效率,其中土地面积规模与农业环境效率之间呈倒U型关系,劳动投入和资本投入对农业生产环境效率均有负向的影响,而农业产出规模的增加将促进农业环境效率的提升.     

The Variability of Estimates of Variance, and Its Effect on Power Analysis in Monitoring Design

Power analysis can be a valuable aid in the design of monitoringprograms. It requires an estimate of variance, which may come from a pilot study or an existing study in a similar habitat. For marine benthic infauna, natural variation in abundances canbe considerable, raising the question of reliability of varianceestimates. We used two existing monitoring programs to generatemultiple estimates of variance. These estimates were found to differ from nominated best estimates by 50% or more in 43% of cases, in turn leading to under or over-estimation of samplesize in the design of a notional monitoring program. The twostudies, from the same general area, using the same samplingmethods and spanning a similar time scale, gave estimatesvarying by more than an order of magnitude for 25% of taxa.We suggest that pilot studies for ecological monitoring programsof marine infauna should include at least two sampling times.     

Prenatal diagnosis for huntington's disease: A molecular and psychological study

Two linked probes were used to determine the Huntington's disease status of the fetus conceived by a woman affected with the condition. The fetus was found to be unaffected with a certainty of 97 per cent. The ethical issues associated with presymptomatic testing were avoided since the mother presented with initial symptoms of Huntington's disease, but other psychological and ethical issues arose. The concerns of an affected woman planning a pregnancy, and the dilemmas involved in decision-making regarding prenatal diagnosis and possible selective abortion were exposed and explored with the patient and her husband.     

UASB反应器常温下处理生活污水的中试研究

中试试验研究讨论了利用颗粒污泥接种的UASB反应器常温下处理生活污水的运行性能。在7～31℃温度范围内处理生活污水,考察了不同温度、不同负荷条件下反应器的处理效率,讨论了各参数对反应器运行的影响,为UASB反应器常温下处理生活污水提供理论和实践指导。     

城市水业私有化问题分析及研究

私人投资水业在今后一定时间内是解决城市基础设施建设的主要手段之一.它能够解决城市基础设施投资资金短缺的问题;实现基础设施行业投资结构多元化,促进体制改革;引入竞争机制,提高服务质量;引入先进技术与科学的管理手段,提高经营管理效率.本文首先介绍了私有化的概念,进而指出城市水业的私有化并不是解除政府保障基本水服务的职责,而是完成运营者到监管者的转变,最后以典型案例分析了私人投资水业存在着巨大的机会和风险.     

森林植被影响径流形成机制研究进展

径流形成机制研究在水文学领域中具有十分重要的意义,且受到越来越广泛的重视。水文环境以及水文通量的空间异质性和时间变化性导致了水文过程的尺度依赖性和非线性特征,没有对水文过程较为清晰的认识,就不能将某一地区某一流域森林植被变化水文生态效应的研究结果简单地外推到其他地区和其他流域。开发基于物理过程分布式参数水文模型可以为认识森林植被变化的生态学后效和客观评价森林植被水文生态效益提供可行的工具。但是要实现这一目标,研究森林植被影响径流形成机制是问题的核心所在。另一方面,认识森林影响径流形成机制有助于研究水文学中的尺度问题。研究森林植被影响径流形成机制的主要方法包括水文测验、同位素示踪和动力水文学计算等,研究的空间尺度则为坡面与流域相接合。从已有的研究成果来看,森林植被影响径流形成机制可以概括为:①森林流域径流形成为变动源区产流机制;②森林流域径流形成主要受饱和地表径流、亚表层径流和地下径流的控制;③森林流域径流形成机制是相互作用和相互转化的;④优先流在森林流域径流形成中起到了至关重要的作用。     

新型内电解铁屑过滤塔在印染废水工业化规模处理中的应用

介绍了一种新型内电解铁屑过滤塔在印染废水工业化规模处理中的应用。在弱酸性条件下 ,该类型铁屑滤塔色度去除率高达 90 % ,废水可生化性提高 30 % ,运行一年半无板结和钝化现象。与后续的生化处理单元结合 ,出水稳定 ,实现达标排放。     

Dystrophin protein and rflp analyis for fetal diagnosis and carrier confirmation of duchenne muscular dystrophy

A pregnant woman with indeterminate Duchenne muscular dystrophy (DMD) carrier status, but with DMD diagnosed in her deceased brother (unavailable for study), presented for prenatal diagnosis, intending to continue the pregnancy only if proven unaffected with DMD with near absolute certainty. Creatine kinase (CK) assays to clarify carrier status were inconclusive. Male sex in the fetus was identified, but DNA restriction fragment length polymorphism (RFLP) analysis was not yet available to this centre to investigate the possible transmission of the DMD gene, and the pregnancy was terminated. Tissue histology and dystrophin protein analysis demonstrated the absence of DMD. In a situation with proven maternal carrier status, future fetal inheritance of the opposite maternal X chromosome would indicate the presence of DMD. However, maternal carrier status remained in doubt through a second pregnancy, even with RFLP studies, and was finally established when dystrophin analysis confirmed the presence of DMD in the second fetus. Histologic findings are presented, contrasting features in the two fetuses. The value of dystrophin analysis for establishing the diagnosis of fetal DMD, in this case proving maternal carrier status in a difficult situation, and for demonstrating DMD gene:RFLP haplotype relationships is illustrated.