Resilience metrics for cyber systems

As federal agencies and businesses rely more on cyber infrastructure, they are increasingly vulnerable to cyber attacks that can cause damages disproportionate to the sophistication and cost to launch the attack. In response, regulatory authorities call for focusing attention on enhancing infrastructure resilience. For example, in the USA, President Obama issued an Executive Order and policy directives focusing on improving the resilience and security of cyber infrastructure to a wide range of cyber threats. Despite the national and international importance, resilience metrics to inform management decisions are still in the early stages of development. We apply the resilience matrix framework developed by Linkov et al. (Environ Sci Technol 47:10108–10110, 2013) to develop and organize effective resilience metrics for cyber systems. These metrics link national policy goals to specific system measures, such that resource allocation decisions can be translated into actionable interventions and investments. In this paper, a number of metrics have been identified and assessed using quantitative and qualitative measures found in the literature. We have proposed a generic approach and could integrate actual data, technical judgment, and literature-based measures to assess system resilience across physical, information, cognitive, and social domains.     

Reduction in labile copper in the 7-day Ceriodaphnia dubia toxicity test due to the interaction with zooplankton food

Due to the increased popularity of zooplankton toxicity tests, it is important to investigate potential confounding factors. Though zooplankton food has been studied extensively to meet the nutritional needs of the zooplankton, less research has been done on whether food addition reduces the toxicity of metals in the tested sample. This investigation combines toxicity tests and metal speciation analysis to determine whether the EPA recommended food of YCT (yeast, cerophyll, and trout chow) and Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) reduces copper toxicity by decreasing the concentration of labile copper. Toxicity tests were performed with Ceriodaphnia dubia on culture water spiked with 0, 787, and 1574 nM copper with five different food levels. A Chelex-100 cation exchange resin and a graphite furnace-atomic absorption spectrophotometer were used in conjunction with the toxicity tests to measure the amount of labile copper in the culture water. At the EPA recommended food dosage, the C. dubia food has a chelating capacity of approximately 500 nM Cu. For both concentrations of spiked culture water, the toxicity to C. dubia was reduced with increasing food level, which seemed to be both from a decrease in labile copper concentration and an increase in the nutritional condition of the zooplankton.     

The fate of heavy metals in green waste composting

It has long been known that heavy metals, when in high enough concentration, have the potential to be both phytotoxic and zootoxic. Heavy metals are frequently found as contaminants in green waste. Any such waste that is subsequently segregated for composting theoretically has the potential to retain that possible contamination. To date, there have been a limited number of publications addressing this issue. Most reports have concentrated on the types of heavy metals found in compost and their acceptable levels, rather than the fate of heavy metal contaminants throughout the composting process. This investigation was aimed to identify the fate of cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb) and zinc (Zn) concentrations throughout a fourteen week composting cycle. The results of this study showed a general increase in the removal of Pb, Cu, Cr, and to a much smaller extent Zn, manifested by a decrease in their overall concentrations within the solid fraction of the final product, by 93, 49, 43, and 20 percent respectively. By contrast, there was no decrease in the overall concentration of Cd.     

复合垂直流湿地反应动力学及水流流态的研究

 提出一种新型的复合垂直流湿地系统(IVCW),并对其反应动力学和系统的实际流态进行了研究.经过中试的运行试验,得到了系统对COD去除的反应速率方程,由示踪剂试验确定了系统中水流的停留时间分布(RTD),提出RTD的不同是湿地处理效率差异的主要原因,进而运用串联反应器模型和离散流模型两种非理想流态模型,模拟IVCW的实际水流流态,经过比较发现离散流模型模拟的效果较好.     

直面灾难:美国鉴于印度博帕尔毒气泄漏事件采取的化学品事故应对措施

20多年前，1984年12月3日的后半夜，一股充满甲基酸的毒云从印度博帕尔联合碳化物公司（Union Carbide）的工厂溢出，造成2000多人死亡，上万人受伤，该事件至今仍是世界上最严重的工业事故。4个月以后，该公司的一个经理向美国国会保证，类似博帕尔的事故不会发生在其位于西弗吉尼亚州研究所的同类工厂。但是数月后，     

借助吉布斯抽样器有效地进行野外抽样预测驯鹿(Rangifer tarandus)的空间分布

我们介绍一种估计驯鹿(Rangifer tarandus)的空间分布的方法.描述野生动物物种分布的数据,其内在的空间自相关性包含可以用来提高野外调查效率的信息.我们的数据包括驯鹿粪便小球数、卫星图像和一个数字化地形模型.基于这些综合数据,我们采用普通逻辑回归、自动逻辑回归和吉布斯抽样器预测驯鹿的空间分布.通过训练数据集,对每种方法所采取的不同抽样设计结果进行比较.结果表明,在预测精度(质量)降低15%的情况下,样方数量可减少75%.我们的结果表明,就精度而言,吉布斯抽样器要优于逻辑回归,但结果取决于区域光谱的均质性,以及高度曲线相对位置的取样设计.当对驯鹿的分布进行更精细的建模时(＜1km),我们的结果证明结合空间信息进行预测是必要的.     

An examination of the mobilisation of elements from the skin and bone of the bog body Lindow II and a comparison with Lindow III

The elemental content of samples of tissues derived from a 2,000-year old bog body, Lindow II, are described and the interchange of elements between the body and the surrounding or encompassing anaerobic peat medium is examined. A comparison is made of the chemical ‘fingerprint’ of Lindow II as compared with another bog body referred to as Lindow III. The application of body paint is noted. The bone has retained much of its structure and the Haversian Canal system is recognisable. The presence of a fungus mycelium on the skin samples is noted.