国外航天医学研究的回顾与启示

航天医学是伴随载人航天事业的发展而兴起的一门新兴学科,针对长期空间飞行的"人系统风险",在人体健康和对抗措施、心理行为健康、辐射卫生及先进的人体保障技术等领域开展研究,介绍了国外航天医学研究的进展情况及其启示,促进航天医学理论和技术水平飞速发展,为我国空间站的航天医学研究提供参考。

Prediction of subsidence risk by FMEA using artificial neural network and fuzzy inference system

Construction of metro tunnels in dense and crowded urban areas is faced with many risks, such as sub- sidence. The purpose of this paper was the prediction of subsidence risk by failure mode and effect anal- ysis （FMEA） and fuzzy inference system （FIS）. Fuzzy theory will be able to model uncertainties. Fuzzy FMEA provides a tool that can work in a better way with vague concepts and without sufficient informa- tion than conventional FMEA. In this paper, S and D are obtained from fuzzy rules and 0 is obtained from artificial neural network （ANN）. FMEA is performed by developing a fuzzy risk priority number （FRPN）. The FRPN for two stations in Tehran No.4 subway line is 3.1 and 5.5, respectively. To investigate the suit- ability of this approach, the predictions by FMEA have been compared with actual data. The results show that this method can be useful in the prediction of subsidence risk in urban tunnels.

Population Ageing,Financial Leverage and Systemic Risk

Population ageing and high financial leverage are two common problems .faced by the worM＇s major economies. The recent financial crisis proved that the two issues could lead to systemic risk if not handled properly. Based on dynamic panel data from 1980 to 2012 in 119 countries, this paper examines the impact of population ageing on financial leverage J？om an empirical point of view and finds that there is a signOqcant inverted U-shape relationship between the two. In addition, empirical studies show that after passing the ＂turning point＂ of ageing, there will be a marked increase in the probability of financial crisis during the ＂deleveraging＂ process. It can be projected from the empirical conclusions of this paper that China will likely enter the range of a turning point between 2019 and 2028. After that, population ageing, deleveraging and asset price collapse may have a ＂resonance＂ effect to severely impact the stability of the financial system. Therefore, China should shift to more proactive macro financial regulations as quickly as possible, as dynamic and robust management of financial leverage and forward-looking control of bubbles could ensure that the financial system remain flexible enough to avoid systemic risk to the greatest extent.

Risk of Getting Nosocomial Water-Borne Infections from the Main Water Systems in Hospitals

Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be considered when water supply to new buildings is planned. The aim of this paper is to review situations that have to be considered in new buildings and give an example on a new water supply contaminated with biofilm producing water bacteria and the precautions introduced to eliminate the contamination. When new buildings are planned it should be considered where to get the water and what is the microbiological quality of the water. If the water is contaminated there will be troubles from the beginning. The material for the pipes should be considered as biofilm which is produced in greater amounts and faster in PEG pipes than in stainless steel pipes. The choice of material depends on the expected lifetime of the building, the dimensions of the pipes, and the choice of forceps, how often the taps are used and thereby the flow in the system. The higher flow the less and slower biofilm formation. It is important to reduce the number of taps to a minimum to ovoid ＂dead ends＂ if they are not or only seldom used. Alternatively all taps could be opened automatically regularly. It is important to establish precautions to ovoid contamination of the water system in the period from when it is established until the building is taken in use. The period can be several months during which the system can act as a ＂dead end＂ if no precautions, such as regularly opening of all taps, are taken. The microbiological quality of the water in the system should be controlled before the building is taken in use. In a new building, where the water supply and the water in the building was not controlled before the building was taken in use, extremely high total and Legionella germ counts were found. The water was disinfected with low concentrations of chloride with very little effect. After disinfection with high concentrations of chloride for few hours and placing a sterile filter at the water entrance both the total and Legionella germ count decreased to an acceptable level.

Global Environmental Change and National Security of China

The concept of security has been redefined since the 1990s. As one of the important factors threatening human security, global environmental change has become a new challenge to the national security and social development. The national security problems caused by global environmental change, on one hand, are closely related to the global environmental problems, and, on the other hand, are manifested in the conflicts of international affairs. The global environmental change severely challenges the future development of China. When it comes to the study on human dimensions of global environmental change in China, much more attention should be paid to issues of important environmental change that may have great impacts on the national security of China, to the scientific assessment of the vulnerabilities of the natural and socialeconomic system of China to the impacts of global environmental change, and to the active establishment of the national risk management system, in which global environmental change should be included, so as to make contribution to sustainable development and construction of harmonious society of China.