ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00823.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00824.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Three methods (multiplicative, additive, and allometric) were developed to extrapolate physiological model parameter distributions across species, specifically from rats to humans. In the multiplicative approach, the rat model parameters are multiplied by the ratio of the mean values between humans and rats. Additive scaling of the distributions is denned by adding the difference between the average human value and the average rat value to each rat value. Finally, allometric scaling relies on established extrapolation relationships using power functions of body weight. A physiologically‐based pharmacokinetic model was fitted independently to rat and human benzene disposition data. Human model parameters obtained by extrapolation and by fitting were used to predict the total bone marrow exposure to benzene and the quantity of metabolites produced in bone marrow. We found that extrapolations poorly predict the human data relative to the human model. In addition, the prediction performance depends largely on the quantity of interest. The extrapolated models underpredict bone marrow exposure to benzene relative to the human model. Yet, predictions of the quantity of metabolite produced in bone marrow are closer to the human model predictions. These results indicate that the multiplicative and allometric techniques were able to extrapolate the model parameter distributions, but also that rats do not provide a good kinetic model of benzene disposition in human

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00825.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Road traffic accident involvement rates show clear age and gender differences which may in part be accounted for by differences in risk perception and perceptions of driving competence. The present study extends and replicates that of Matthews and Moran (1986). Young (18–30 years) and older (45–60 years) male and female drivers responded to a questionnaire on perceived accident risk and driving competence (judgment and skill) with respect to themselves and four target groups, and also rated a series of videotaped driving sequences with respect to likelihood of accident occurrence and perceived driving competence. Results showed that effects of rater characteristics were generally confined to the questionnaire. Younger males were perceived as most likely to experience an accident and were judged to be lower than other groups in driving competence. Younger groups showed little bias against older groups andvice versa, but gender‐related bias was apparent. The findings of Matthews and Moran were generally confirmed. The results are discussed with reference to four main issues: (1) demographic bias effects—which are generally weak; (2) stereotyping on the basis of gender and/or age of driver; (3) group‐specific bias; (4) self‐app

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00826.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

There are a number of sources of variability in food consumption patterns and residue levels of a particular chemical (e.g., pesticide, food additive) in commodities that lead to an expected high level of variability in dietary exposures across a population. This paper focuses on examples of consumption pattern survey data for specific commodities, namely that for wine and grape juice, and demonstrates how such data might be analyzed in preparation for performing stochastic analyses of dietary exposure. Data from the NIAAA/NHIS wine consumption survey were subset for gender and age group and, with matched body weight data from the survey database, were used to define empirically‐based percentile estimates for wine intake (μl wine/kg body weight) for the strata of interest. The data for these two subpopulations were analyzed to estimate 14‐day consumption distributional statistics and distributions for only those days on which wine was consumed. Data subsets for all wine‐consuming adults and wine‐consuming females ages 18 through 45, were determined to fit a lognormal distribution (R2= 0.99 for both datasets). Market share data were incorporated into estimation of chronic exposures to hypothetical chemical residues in imported table wine. As a separate example, treatment of grape juice consumption data for females, ages 18–40, as a simple lognormal distribution resulted in a significant underestimation of intake, and thus exposure, because the actual distribution is a mixture (i.e., multiple subpopulations of grape juice consumers exist in the parent distribution). Thus, deriving dietary intake statistics from food consumption survey data requires careful analysis of the underlying empirical dis

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00827.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Public reaction to chemical technologies has included a perception that chemical exposure is a contributor to human health problems. Though these perceptions sometimes correspond with technical assessments of chemical risks, at other times they do not. This paper presents a descriptive model of the relationship between perception of one's health status and a set of factors that are used by individuals as part of causal reasoning about the meaning of somatic change. The model incorporates both personal events and experiences associated with somatic change (e.g., stress, sensory cues), as well as aspects of an individual's social context in which perceptions of chemical risks serve as a powerful framework for attributing meaning to chemical exposure. Within this model, the causal inferences that people make about the effects of chemical exposure on symptomatology are viewed as part of a natural, psychological adaptation in which the individual seeks to decrease their uncertainty about the factors or conditions that cause them to feel as they do.

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00828.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Uncertainty analyses typically recognize separate stochastic and subjective sources of uncertainty, but do not systematically combine the two, although a large amount of data used in analyses is partly stochastic and partly subjective. We have developed methodology for mathematically combining stochastic and subjective sources of data uncertainty, based on new “hybrid number” approaches. The methodology can be utilized in conjunction with various traditional techniques, such as PRA (probabilistic risk assessment) and risk analysis decision support. Hybrid numbers have been previously examined as a potential method to represent combinations of stochastic and subjective information, but mathematical processing has been impeded by the requirements inherent in the structure of the numbers, e.g., there was no known way to multiply hybrids. In this paper, we will demonstrate methods for calculating with hybrid numbers that avoid the difficulties. By formulating a hybrid number as a probability distribution that is only fuzzily known, or alternatively as a random distribution of fuzzy numbers, methods are demonstrated for the full suite of arithmetic operations, permitting complex mathematical calculations. It will be shown how information about relative subjectivity (the ratio of subjective to stochastic knowledge about a particular datum) can be incorporated. Techniques are also developed for conveying uncertainty information visually, so that the stochastic and subjective components of the uncertainty, as well as the ratio of knowledge about the two, are readily apparent. The techniques demonstrated have the capability to process uncertainty information for independent, uncorrelated data, and for some types of dependent and correlated data. Example applications are suggested, illustrative problems are shown, and graphical results are gi

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00829.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Risk characterization objectives include evaluating the weight of evidence underlying risk determinations, communicating that evaluation to nonexperts, guiding risk assessors to achieve consistency, and preserving deference for those reasonable expert judgments inherent in any risk determination. Similar objectives are shared by American courts that face the gatekeeping task of screening scientific evidence before it is presented to nonexpert factfinders, such as juries. This article surveys the judicial gatekeeping concepts of relevance, evidentiary reliability, legal sufficiency, presumptions, and standards of proof (particularly, preponderance of the evidence). It examines recent court decisions that have applied these concepts to the kinds of scientific information common in risk assessments, and suggests how to adapt these gatekeeping concepts for use in weight‐of‐evidence characterization. If we can develop and adopt a neutral framework for characterizing the weight of evidence underlying risk assessments, it might help clarify not only the current debate over risk characterization and risk management, but also the drafting of treaty provisions, such as those invoking the Precautionary Principle of international environmental

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00830.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The objective of this research is to present a method for evaluating the performance of access control security systems, such as airport security operations. This requires the examination of security system architectures, which involve security technology devices and the algorithms that coordinate their operations. Dependence between device responses in multiple‐device systems is a critical practical issue in assessing the performance of such architectures, though no results on this problem have appeared in the literature. This paper presents a method for evaluating when multipledevice security systems with overlapping capabilities are cost‐effective. This is achieved using adependency structurefor security system devices to quantify how various technologies interact and to measure the impact of device dependence on system error probabilities. A measure of device response dependence for a two‐device system is defined and its properties are explored, including bounds on the dependency measure. The effect of dependence on the system Type I and Type II error probabilities is examined for the two‐device system. System performance is compared for independent vs. dependent device responses and desirable dependence relationships are identified. Results are also presented for a cascading sequence of devices. An example is presented to illustrate the results for the two‐device system. Implications of these results are discussed, such as how they can be used to identify the optimal use of security devices and to determine whether new technologies warrant i

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00831.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

The decision‐making process used by the National Toxicology Program (NTP) in its evaluation of long‐term rodent carcinogenicity studies was investigated to determine whether or not this procedure resulted in an excessive number of false positive or false negative outcomes. All site‐specific tumor incidences that were found to be significantly (p90%) for thi

ISSN:0272-4332    

DOI:10.1111/j.1539-6924.1996.tb00832.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY