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Predictions of river water quality models are subject to substantial uncertainties, which depend not only on parameterization and calibration strategies but also on the structure of the conceptual model itself. To evaluate the importance of this effect and associated implications for stochastic models, investigations were conducted based on a segment of the Potomac River in the eastern USA. Two commonly used conceptual representations of real-world processes were used, and their simulation of DO, BOD and NH4 components scrutinized. A GLUE approach to the inverse problem was then used to examine how uncertainty changed along the river network for each conceptual model. Differences were observed not only between deterministic instances of each conceptual model, but also between their response surfaces as a whole. Uncertainties within the river network are substantially influenced by the selection of calibration data used, as well as the primary source of the constituent examined. The suggested methodology can be used to test conceptual model validity for specific applications. The results of this study will help users select and assess models for varied problems, and refine appropriate data collection and monitoring schemes. [ABSTRACT FROM AUTHOR]

An obituary for American mathematician John F. Nash Jr. is presented.

Objective: To develop consensus-based recommendations for measures to be taken by medical and public health professionals following the use of anthrax as a biological weapon against a civilian population.Participants: The working group included 21 representatives from staff of major academic medical centers and research, government, military, public health, and emergency management institutions and agencies.Evidence: MEDLINE databases were searched from January 1966 to April 1998, using the Medical Subject Headings anthrax, Bacillus anthracis, biological weapon, biological terrorism, biological warfare, and biowarfare. Review of references identified by this search led to identification of relevant references published prior to 1966. In addition, participants identified other unpublished references and sources.Consensus Process: The first draft of the consensus statement was a synthesis of information obtained in the formal evidence-gathering process. Members of the working group provided formal written comments which were incorporated into the second draft of the statement. The working group reviewed the second draft on June 12, 1998. No significant disagreements existed and comments were incorporated into a third draft. The fourth and final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members.Conclusions: Specific consensus recommendations are made regarding the diagnosis of anthrax, indications for vaccination, therapy for those exposed, postexposure prophylaxis, decontamination of the environment, and additional research needs. [ABSTRACT FROM AUTHOR]

Pharmaceutical companies exist today in a hostile legal and regulatory environment. The threat of product liability in the pharmaceutical industry has risen to the point where it stifles research and development, especially for contraceptive and psychotropic drugs. Regulatory sanctions against the industry are more likely now than in the past since the Food and Drug Administration (FDA) has placed significant emphasis on regulatory inspection and enforcement. Industrial pathologists play a critical role in defending their company in product liability litigation and from regulatory sanctions. In-house and contract pathologists should be prepared to give expert testimony in court and ensure that an effective document retention policy is implemented. Pathologists should know the limits of the FDA's inspection authority and be aware of the "pitfalls" of the FDA's new Fraud Policy. In addition to keeping abreast of science, industrial pathologists today can best serve the pharmaceutical industry if they maintain an awareness of legal issues that pose a threat to the future success of the industry.