Documenting Problem Formulation

Application of Uncertainty Analysis to Ecological Risk of Pesticides 

Chapman PM, McDonald BG, Lawrence GS. 2002. Weight-of-evidence issues and frameworks for sediment quality (and other) assessments. Human Ecol Risk Assess 8 1489-1515. 

Ferenc S, Foran J, editors, 2000. Multiple stressors in ecological risk and impact assessment approaches to risk estimation. Pensacola (EL) SETAC and Chemistry Press. 

Moore DRJ, Sample BE, Suter GW, Parkhurst BR, Teed RS. 1999. Risk-based decision making the East Fork Poplar Creek case smdy. Environ Toxicol Chem 18 2954—2958. 

Morgan MG, Henrion M. 1990. Uncertainty a guide to dealing with uncertainty in quantitative risk and policy analysis. Cambridge (UK) Cambridge University Press. 

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In the mid-70s, it was a generally expressed opinion that there could be as many as 100 formulation factors that might affect bioavailability or bioequivalence. In fact, most of the documented problems centered around the use of the hydrophobic magnesium stearate as a lubricant or use of a hydrophobic shellac subcoat in the production of sugar-coated... 

The ecological risk assessment was conducted in accordance with the USEPA guidance document Guidelines for Ecological Risk Assessment (USEPA, 1998) . A four-step assessment process was adopted problem formulation, exposure characterization, characterization of ecological effects and risk evaluation. 

A PF/SAP document was prepared in order to guide the implementation and interpretation of the overall sediment quality triad. Objectives in a PF/SAP are identical to that of a problem formulation following a traditional ERA approach (U.S. EPA, 1998). PF/SAP documents are often submitted for regulatory approval prior to any sample collection in order to facilitate dialogue between interested parties. Our experience suggests that this dialogue during the problem formulation... 

Although many hypotheses may be generated during problem formulation, only those that are considered most likely to contribute to risk are selected for further evaluation in the analysis phase. For these hypotheses, the conceptual model describes the approach that will be used for the analysis phase and the types of data and analytical tools that will be needed. It is important that hypotheses that are not carried forward in the assessment because of data gaps be acknowledged when uncertainty is addressed in risk characterization. Professional judgment is needed to select the most appropriate risk hypotheses, and it is important to document the selection rationale. 

A method to circumvent the problem of chalcogen excess in the solid is to employ low oxidation state precursors in solution, so that the above collateral reactions will not be in favor thermodynamically. Complexation strategies have been used for this purpose [1, 2]. The most established procedure utilizes thiosulfate or selenosulfate ions in aqueous alkaline solutions, as sulfur and selenium precursors, respectively (there is no analogue telluro-complex). The mechanism of deposition in such solutions has been demonstrated primarily from the viewpoint of chemical rather than electrochemical processes (see Sect. 3.3.1). Facts about the (electro)chemistry of thiosulfate will be addressed in following sections for sulfide compounds (mainly CdS). Well documented is the specific redox and solution chemistry involved in the formulation of selenosulfate plating baths and related deposition results [11, 12]. It is convenient to consider some elements of this chemistry in the present section. 

Illustrative performance properties for a "general purpose polycarbonate," and for the same resin modified with the additive formulations "700" (without PTFE) and "800" (with PTFE) are summarized in Table IV (adapted from reference 32). It is clear that the objective of minimal effect on performance properties has been attained for this system. It is evident that flame retardant effectiveness attained with minimal levels of additive can provide optimum solutions to the problem of decreasing flammability without sacrifice in performance properties. Work documented to date suggests that in depth studies of thermal degradation such as reported for aromatic sulfonates in polycarbonates (28) would be rewarding for other systems. 

Unless there are specific instructions in the protocol to the contrary, there should be a clearly documented trail of the drugs supplies that came in, what was administered to the subjects and what was returned by the subject in terms of unused medication. Any relaxation of drug accountability, as is seen sometimes in a multicentre study of many thousand subjects, can cause problems in monitoring the correct formulations and dosages given to the subjects. The significance of the... 

The purpose of this chapter is to document the nature of the enzyme barrier that macromolecular drugs will encounter during their passage down the human gastrointestinal tract. I will discuss the peptidases that digest peptides and proteins and the nucleases that will hydrolyse nucleic acids and also briefly consider other enzymes that may affect the behaviour of the newer generation of pharmaceutical formulations. It is very important to consider both the qualitative aspects of the problem, that is, the specificity of the digestive... 

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