Relevance of radiation compensation litigation to compensation for toxic exposures

Several recent court decisions add to the growing body of law concerning the responsibility of Government in radiation matters and the quantum of proof needed to show causation between radiation exposures and certain types of cancer and leukemia. The courts have also been addressing a wide range of compensation claims for exposures to toxic chemicals with demonstration of causation being a particularly difficult task. Meanwhile, the Congress has been attempting to legislate a far reaching administrative and judicial framework for compensating toxic victims, including an easing of burden-of-proof requirements for demonstrating causation and a broadening of the basis for admissibility of scientific evidence. Drawing parallels between radiation and toxic exposure problems can be both instructive and misleading. Some of the technical issues are quite similar, including the importance of person-specific exposure estimates and of epidemiological studies. However, the uncertainties associated with toxic exposures are usually far greater, and the scientific data base for relating exposures and effects is much more uncertain.     

Below-cost timber sales and the political marketplace

Political pressures exist to increase the economic efficiency of timber management and production on the national forests managed by the USDA Forest Service. There is growing belief both outside and within the Forest Service that current levels of timber production, and most particularly uneconomic timber production, should be reduced. Many argue that eliminating uneconomic timber management programs will both save money and reduce environmental degradation. This article traces the political evolution of the focus on economic efficiency in timber production and explores the political-institutional factors that are shaping the current policy debate. The below-cost issue is less about economic efficiency than it is about political advantage and alternative political visions of the societal role of the nation's national forests now and in the future.     

Soil biota drive expression of genetic variation and development of population-specific feedbacks in an invasive plant

Invasive plant species alter soils in ways that may affect the success of subsequent generations, creating plant-soil feedbacks. Ailanthus altissima is an invasive tree introduced two centuries ago to North America. We hypothesized that geographically distinct populations of A. altissima have established feedbacks specific to their local environment, due to soil communities cultivated by A. altissima. We collected seeds and soils from three populations in the eastern United States, and in the greenhouse reciprocally planted all families in all collected soils as well as in a control mixed soil, and in soils that had been irradiated for sterilization. There were positive plant-soil feedbacks for two populations in the live field-collected soils, but strong negative feedbacks for the third population. There were no population-level performance differences or feedbacks in the sterilized population locale soils, supporting a soil biotic basis for feedbacks and for the expression of genetic differentiation in A. altissima. If populations of Ailanthus altissima vary in the extent to which they benefit from and promote these plant-soil biota feedbacks, the interaction between invader and invaded community may be more important in determining the course of invasion than are the characteristics of either alone.     

Uniting multi‐adult households during emergency evacuation planning

When a no‐notice emergency prompts an evacuation, family members in different locations throughout a city may unite so that they can evacuate as a group. This paper draws on data from more than 300 interviews conducted in the metropolitan area of Chicago, Illinois, United States. The study uses discrete choice models to analyse the expectations of respondents regarding whether their likely plans for evacuation involve gathering spouses, parents, adult‐age children, and/or non‐family members. In addition, it addresses the matter of whether respondents plan to reunite with family members at home. Individuals' access to a personal car is the dominating factor in predicting whether respondents plan to gather a spouse. Being the parent of a child under the age of 18 years increases the tendency to report planning to reunite with family members at home. Both commute mode and car availability are not significantly associated with plans to reunite at home.     

Histological,chemical, and morphological reexamination of the “heart” of a small Late Cretaceous <Emphasis Type="BoldItalic">Thescelosaurus</Emphasis>

A three-dimensional, iron-cemented structure found in the anterior thoracic cavity of articulated Thescelosaurus skeletal remains was hypothesized to be the fossilized remains of the animal’s four-chambered heart. This was important because the finding could be interpreted to support a hypothesis that non-avian dinosaurs were endothermic. Mammals and birds, the only extant organisms with four-chambered hearts and single aortae, are endotherms. The hypothesis that this Thescelosaurus has a preserved heart was controversial, and therefore, we reexamined it using higher-resolution computed tomography, paleohistological examination, X-ray diffraction analysis, X-ray photoelectron spectroscopy, and scanning electron microscopy. This suite of analyses allows for detailed morphological and chemical examination beyond what was provided in the original work. Neither the more detailed examination of the gross morphology and orientation of the thoracic “heart” nor the microstructural studies supported the hypothesis that the structure was a heart. The more advanced computed tomography showed the same three areas of low density as the earlier studies with no evidence of additional low-density areas as might be expected from examinations of an ex situ ostrich heart. Microstructural examination of a fragment taken from the “heart” was consistent with cemented sand grains, and no chemical signal consistent with a biological origin was detected. However, small patches of cell-like microstructures were preserved in the sandstone matrix of the thoracic structure. A possible biological origin for these microstructures is the focus of ongoing investigation.     

Prenatal identification of a Y-chromosome deletion by Y-specific single copy DNA probes

A sex chromosome deletion was identified in the course of prenatal diagnosis for maternal age. Ultrasound pictures revealed male fetal sex and a comparison with the father's Y chromosome suggested that the altered chromosome might be a de novo deletion of the Y chromosome. DNA hybridization with five human Y-specific probes shows that, among the Y-specific sequences recognized by the probes, only two of them are absent. The normal infant, at birth, was mosaic 46, XYq- /46,XY.     

Risk assessment near uncontrolled hazardous waste sites: Role of monitoring data

The traditional approach of coupling estimates of human exposures to individual chemicals with laboratory studies of the toxicity of the chemicals as the basis for quantitative assessments of risk is not adequate when considering problems near hazardous waste sites. For example, there are (a) too many chemicals and mixtures involved, (b) containment uncertainties, and (c) future exposure problems associated with groundwater and soil contamination. Among the items to be considered in expanding the dimensions of risk assessment methodologies of the past are (a) identification of chemical groups or of dominant toxic chemicals of principal concern and the likely man-made as well as natural pathways for environmental migration, (b) the role of biological monitoring in addition to traditional monitoring approaches, and (c) the coupling of monitoring data with past, current, and future population activity patterns and with epidemiological and other health data.Monitoring data is a key in risk assessments since there is little likelihood that materials balances or modelling will provide authoritative information concerning exposure levels. The use of monitoring data from control areas and from nationwide baseline surveys in developing comparative risk assessments is particularly important. Finally, recent experience provides us with a number of practical guidelines for designing and carrying out monitoring programs that will provide authoritative and useful data. *** DIRECT SUPPORT *** AZ802019 00002