马达海洋区块分段压制多次波方法

马达海洋工区海底深度变化很大，多次波异常发育，多次波衰减一直是该区地震资料处理难题之一。首先分 析与自由表面相关多次波衰减方法（SRME）、预测反褶积、抛物线Radon 变换的方法原理，针对各方法的不同特点制 定方案：采用SRME 方法衰减与自由表面相关的多次波，预测反褶积方法压制层间多次波，抛物线Radon 变换法衰减 剩余的多次波。实际资料处理表明：这种分步分段压制多次波的方法能够很好地衰减海底深度变化范围大、海底构造 复杂的海洋地震资料的多次波，很好地改善海洋地震资料的成像效果。实际资料处理表明，这种分段压制多次波方法 能够广泛应用于海底深度变化大，海底地质构造复杂的海洋地震资料多次波衰减处理。     

A parallel analysis of individual and ecological data on residential radon and lung cancer in south-west England

Parallel individual and ecological analyses of data on residential radon have been performed using information on cases of lung cancer and population controls from a recent study in south-west England. For the individual analysis the overall results indicated that the relative risk of lung cancer at 100 Bq m⁻³ compared with at 0 Bq m⁻³ was 1.12 (95% confidence interval (0.99, 1.27)) after adjusting for age, sex, smoking, county of residence and social class. In the ecological analysis substantial bias in the estimated effect of radon was present for one of the two counties involved unless an additional variable, urban–rural status, was included in the model, although this variable was not an important confounder in the individual level analysis. Most of the methods that have been recommended for overcoming the limitations of ecological studies would not in practice have proved useful in identifying this variable as an appreciable source of bias.     

Radon Testing Behavior in a Sample of Individuals with High Home Radon Screening Measurements

Although radon exposure has been identified as the second leading cause of lung cancer, fewer than 6% of U.S. homeowners test their homes for radon. This report examines participants'follow-up radon testing behavior subsequent to receiving an initial screening radon level greater than 20 pCi/L. Sixty-two participants in the Iowa State-Wide Rural Radon Screening Survey who had radon screening measurements over 20 pCi/L were questioned by phone survey 3 months after receipt of their radon screening result to assess: whether participants were aware of radon's health risk; if participants recalled the radon screening results; how participants perceived the relative health risk of radon and whether participants planned follow-up radon testing. Only 19% of the respondents specifically identified lung cancer as the possible adverse health outcome of high radon exposure, and the majority of participants underestimated the health risks high radon levels pose when compared to cigarettes and x-rays. In addition, less than one third (29%)of the participants actually remembered their radon screening level within 10 pCi/L 3 months after receiving their screening results. Only 53% of the individuals correctly interpreted their screening radon level as being in the high range, and only 39% of the participants planned follow-up radon measurements. Receipt of radon screening test results indicating high radon levels was not an adequate motivational factor in itself to stimulate further radon assessment or mitigation. Our findings suggest that free radon screening will not result in a dramatic increase in subsequent homeowner initiated remediation or further recommended radon testing.     

Fitting Second-Order Finite Mixture Models to Data with Many Censored Values Using Maximum Likelihood Estimation

Finite mixture models, that is, weighted averages of parametric distributions, provide a powerful way to extend parametric families of distributions to fit data sets not adequately fit by a single parametric distribution. First-order finite mixture models have been widely used in the physical, chemical, biological, and social sciences for over 100 years. Using maximum likelihood estimation, we demonstrate how a first-order finite mixture model can represent the large variability in data collected by the U.S. Environmental Protection Agency for the concentration of Radon 222 in drinking water supplied from ground water, even when 28% of the data fall at or below the minimum reporting level. Extending the use of maximum likelihood, we also illustrate how a second-order finite mixture model can separate and represent both the variability and the uncertainty in the data set.     

Review of Radon and Lung Cancer Risk

Radon, a long-established cause of lung cancer in uranium and other underground miners, has recently emerged as a potentially important cause of lung cancer in the general population. The evidence for widespread exposure of the population to radon and the well-documented excess of lung cancer among underground miners exposed to radon decay products have raised concern that exposure to radon progeny might also be a cause of lung cancer in the general population. To date, epidemiological data on the lung cancer risk associated with environmental exposure to radon have been limited. Consequently, the lung cancer hazard posed by radon exposure in indoor air has been addressed primarily through risk estimation procedures. The quantitative risks of lung cancer have been estimated using exposure-response relations derived from the epidemiological investigations of uranium and other underground miners. We review five of the more informative studies of miners and recent risk projection models for excess lung cancer associated with radon. The principal models differ substantially in their underlying assumptions and consequently in the resulting risk projections. The resulting diversity illustrates the substantial uncertainty that remains concerning the most appropriate model of the temporal pattern of radon-related lung cancer. Animal experiments, further follow-up of the miner cohorts, and well-designed epidemiological studies of indoor exposure should reduce this uncertainty.     

Cancer Fatalities from Waterborne Radon (Rn-222)

A model of the biokinetics of radon in the human body following ingestion is developed from existing data. Calculations of the probability of cancer fatality from use of radon-laden water in the home then are presented. The pathways of emanation and ingestion are examined and shown to lead to roughly equal risks. The probability of fatal cancer resulting from lifetime use of water at a radon concentration of 1 pCi/L is shown to be 1 X 10(-6), with a reasonable range between 2 X 10(-7) and 5 X 10(-6). The allowed concentration consistent with an excess risk of 10(-4) then is approximately 100 pCi/L, which is exceeded in a significant fraction of U.S. water supplies. The lifetime number of premature deaths due to waterborne radon in the U.S. is estimated to lie between 5000 and 125,000, with a best estimate of 25,000.     

An Analysis of the Uncertainties in Estimates of Radon-Induced Lung Cancer

A recent report by the National Academy of Sciences estimates that the radiation dose to the bronchial epithelium, per working level month (WLM) of radon daughter exposure, is about 30% lower for residential exposures than for exposures received in underground mines. Adjusting the previously published BEIR IV radon risk model accordingly, the unit risk for indoor exposures of the general population is about 2.2 x 10(-4) lung cancer deaths (lcd)/WLM. Using results from EPA's National Residential Radon Survey, the average radon level is estimated to be about 1.25 pCi/L, and the annual average exposure about 0.242 WLM. Based on these estimates, 13,600 radon-induced lcd/yr are projected for the United States. A quantitative uncertainty analysis was performed, which considers: statistical uncertainties in the epidemiological studies of radon-exposed miners; the dependence of risk on age at, and time since, exposure; the extrapolation of risk estimates from mines to homes based on comparative dosimetry; and uncertainties in the radon daughter levels in homes and in the average residential occupancy. Based on this assessment of the uncertainties in the unit risk and exposure estimates, an uncertainty range of 7000-30000 lcd/yr is derived.     

Evaluating Risk Communication: Narrative vs. Technical Presentations of Information About Radon

This paper reports on an experiment to test the hypothesis that people respond better to risk communication that reflects more closely the conditions of their social and cultural lives. The experiment used the case of radon to determine whether technical or narrative forms of risk communication were more effective at drawing people's attention, imparting information, and modifying behavior. Two series of articles on radon were placed in the local newspapers of two Massachusetts communities. Homeowner attitudes, knowledge, and responses were monitored in baseline and follow-up telephone surveys. A third community was selected for comparison. The newspaper series were developed on the basis of previous research and six focus groups conducted with homeowners. The technical series presented authoritative, factual risk information, in the scientific style of the passive voice with generalized and impersonal language. The narrative series consisted of dramatized accounts of individuals making decisions about radon testing and mitigation, written in a more personal style. The findings from the focus groups confirm the results of previous studies, but the small size of the follow-up samples was a limiting factor in drawing definitive conclusions about the relative effectiveness of the two formats. The experiment demonstrates the difficulty of any risk communication effort on radon and underscores the need for good research design.(ABSTRACT TRUNCATED AT 250 WORDS)     

Multivariate Weibull and Pareto Distributions in Hilbert Space

Two general multivariate distributions in a real separable Hilbert space H are introduced in this article, one is multivariate Weibull distribution (denoted by GMW^H), the other is multivariate Pareto distribution (denoted by GMP^H). They are more general than the existing references. Some characterization theorems of the GMW^H and GMP^H via an intensively monotone operator are proved. The limiting behaviors and the interrelationship between the GMW and GMP in Euclidean space are also studied.     

Correlating point-referenced radon and areal uranium data arising from a common spatial process

Summary.  Because exposure to radon gas in buildings is a likely risk factor for lung cancer, estimation of residential radon levels is an important public health endeavour. Radon originates from uranium, and therefore data on the geographical distribution of uranium in the Earth's surface may inform about radon levels. We fit a Bayesian geostatistical model that appropriately combines data on uranium with measurements of indoor home radon in the state of Iowa, thereby obtaining more accurate and precise estimation of the geographic distribution of average residential radon levels than would be possible by using radon data alone.