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Risks associated with toxicants in food are often controlled by exposure reduction. When exposure recommendations are developed for foods with both harmful and beneficial qualities, however, they must balance the associated risks and benefits to maximize public health. Although quantitative methods are commonly used to evaluate health risks, such methods have not been generally applied to evaluating the health benefits associated with environmental exposures. A quantitative method for risk-benefit analysis is presented that allows for consideration of diverse health endpoints that differ in their impact (i.e., duration and severity) using dose-response modeling weighted by quality-adjusted life years saved. To demonstrate the usefulness of this method, the risks and benefits of fish consumption are evaluated using a single health risk and health benefit endpoint. Benefits are defined as the decrease in myocardial infarction mortality resulting from fish consumption, and risks are defined as the increase in neurodevelopmental delay (i.e., talking) resulting from prenatal methylmercury exposure. Fish consumption rates are based on information from Washington State. Using the proposed framework, the net health impact of eating fish is estimated in either a whole population or a population consisting of women of childbearing age and their children. It is demonstrated that across a range of fish methylmercury concentrations (0-1 ppm) and intake levels (0-25 g/day), individuals would have to weight the neurodevelopmental effects 6 times more (in the whole population) or 250 times less (among women of child-bearing age and their children) than the myocardial infarction benefits in order to be ambivalent about whether or not to consume fish. These methods can be generalized to evaluate the merits of other public health and risk management programs that involve trade-offs between risks and benefits.  相似文献   
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The inoperability input-output model (IIM) has been used for analyzing disruptions due to man-made or natural disasters that can adversely affect the operation of economic systems or critical infrastructures. Taking economic perturbation for each sector as inputs, the IIM provides the degree of economic production impacts on all industry sectors as the outputs for the model. The current version of the IIM does not provide a separate analysis for the international trade component of the inoperability. If an important port of entry (e.g., Port of Los Angeles) is disrupted, then international trade inoperability becomes a highly relevant subject for analysis. To complement the current IIM, this article develops the International Trade-IIM (IT-IIM). The IT-IIM investigates the resulting international trade inoperability for all industry sectors resulting from disruptions to a major port of entry. Similar to traditional IIM analysis, the inoperability metrics that the IT-IIM provides can be used to prioritize economic sectors based on the losses they could potentially incur. The IT-IIM is used to analyze two types of direct perturbations: (1) the reduced capacity of ports of entry, including harbors and airports (e.g., a shutdown of any port of entry); and (2) restrictions on commercial goods that foreign countries trade with the base nation (e.g., embargo).  相似文献   
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The behavior of a range of tests assessing the normality of a sequence of independent and identically distributed random variables is investigated.An examination of the empirical significance level of the tests is undertaken for different sample sizes. The empirical power associated with these tests is also calculated under some alternative distributions.  相似文献   
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本文通过对美国赴华与赴日传教士团体的比较研究,认为赴华美国传教士及其子弟在中国和美国本土两线都积极而成功地影响了美国的东亚政策,从而密切了当时的中美关系并推动了抗日战争的顺利发展.相对于此,赴日美国传教士所发挥的作用是微妙和复杂的.同时,本文还通过对传教士历史功能分析模式的再探讨,揭示了传教士在特殊历史时期所扮演的"外交"、"宣传"角色背后的深层蕴含.  相似文献   
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Villa Soft Drinks Ltd, established in 1884, manufactures and bottles spring waters and carbonates for both the growing adult soft drinks market and the more traditional soft drinks market. The company employs just over 100 people split between the manufacturing site in Sunderland and the head office and distribution centre in Washington. One of the fundamental problems affecting the day-to-day running of Villa, and most companies, is communication. There is a lack of awareness of the impact that changes in one department have on other departments (e.g. if production efficiency is increased by 10%, what impact will this have on warehousing?). Villa had recently identified key performance indicators (KPIs) to monitor all aspects of manufacturing performance on a regular basis. This enabled the current production situation to be evaluated and helped familiarize staff with charts and measurements. The use of Pareto analysis and problem solving techniques helped to boost efficiency and utilization. Key performance indicators were then developed in most other departments and are monitored and displayed regularly. The KPIs can be used further to improve transparency across the company by incorporating them in an interactive, interpretative tool to aid communication and understanding at all levels of the company. Individual departmental flow diagrams will be linked together to represent how the company operates. The diagrams will include both material flow and information flow. These data will then be organized in a software package and the end result will be a fully integrated simulation of the company in which any variable can be altered to demonstrate the effect this has on other departments and therefore the company as a whole. This will be an extremely valuable tool for the company as it will have many different applications, such as calculating manning requirements, identifying potential cycle time reductions and optimizing warehouse space.  相似文献   
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The authors reviewed the conflict of interest policies of 9 academic medical centers in the United States and interviewed members of the Institutional Review Boards (IRBs) and Conflict of Interest Committees (COICs) at those institutions. They found that many institutions used processes for reporting and managing conflicts of interest that were more decentralized than the processes described in their policies. Also, most institutions had no clear and comprehensive policy to guide investigators regarding disclosure of conflicts of interest to potential research participants. Considerable differences in understanding of conflict of interest policies were observed between IRB and COIC officials.  相似文献   
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