Risk response, definition

The relationships between the importance measures is based on the assumption that the systems are not reconfigured in response to a component outage. If this is done, the basic definition of the importance measure is still valid but there is not such a simple relationship. Disregarding this complication, some interpretations of the importances may be made. The Bimbaum Importance is the risk that results when the i-th system has failed (i.e., it is the A, term in Equation 2.8-9). Inspection Importance and RRWI are the risk due to accident sequences containing the i-th system. Fussell- Vesely Importance is similar except it is divided by the risk so may be interpreted as the fraction of the total risk that is in the sequences contains the Q-th system. The Risk Achievement Worth Ratio (RAWR) is the ratio of the risk with system 1 failed to the total risk and is necessarily greater than one. The Risk Achievement Worth Increment (RAWI) is the incremental risk increase if system 1 fails and the Risk Reduction Worth Ratio (RRWR) is the fraction by which the risk is reduced if system 1 were infallible. 

A biomarker is here defined as a biological response to an environmental chemical at the individual level or below, which demonstrates a departure from normality. Responses at higher levels of biological organization are not, according to this definition, termed biomarkers. Where such biological responses can be readily measnred, they may provide the basis for biomarker assays, which can be nsed to stndy the effects of chemicals in the laboratory or, most importantly, in the field. There is also interest in their employment as tools for the environmental risk assessment of chemicals. 

Throughout the workshop discussion, as well as in scientific and nonscientific literature, the terms ethnicity and race are often used interchangeably. There are sensitivities surrounding these terms, and trying to get consensus on the definitions was beyond the scope of the workshop. It was recognized that both risk for disease and desirable and undesirable drug responses are variable across the human species, and the variability is dependent on both genetic and environmental factors, many of which may differ between populations. 

To ensure that the rights and welfare of human research participants are protected, the IRB takes on the task of performing a risk vs. benefit analysis. Before a clinical trial can be initiated, foreseeable risks and inconveniences should be weighed against the anticipated benefit for the trial participant and for society (Section 22.2). Risks associated with participation in research should be justified by the anticipated benefits only then, can the trial be initiated. Because this requirement is clearly stated in the federal regulations, it is, therefore, one of the major responsibilities of fhe IRB to assess fhe risks and benefits associated with proposed research. Definitions of fhe terms fhaf fhe IRB uses to assess risk include the following ... 

Other terms often used indiscriminately for the dose-response relationship include concentration-effect relationship and dose-effect relationship. According to the joint OECD/IPCS project (OECD 2003 a), which has developed internationally harmonized generic and technical terms used in chemical hazard and risk assessment, the following definitions have been provided although consensus was not achieved ... 

For continuous data, there are still a number of outstanding issues regarding the benchmark including (Crump 2002) (1) definition of an adverse effect (2) whether to calculate the BMD from a continuous health outcome, or first convert the continuous response to a binary (yes/no) response (3) quantitative definition of the BMD, in particular in such a manner that BMD from continuous and binary data are commensurate (4) selection of a mathematical dose-response model for calculating a BMD (5) selection of the level of risk to which the BMD corresponds and (6) selection of a statistical methodology for implementing the calculation. 

The TGD (EC 2003), Chapter 3.8, on sensitization gives definitions of skin and respiratory sensitization, and provides advice on the data to be used in the effects assessment, evaluation on the available data, and assessment of the dose-response relationship to be used in the EU-specific risk assessments. 

The US-EPA OPPTS test guideline on immunotoxicity (OPPTS 870.7800) provides the following definition Immunotoxicity refers to the ability of a test substance to suppress immune responses that could enhance the risk of infectious or neoplastic disease, or to induce inappropriate stimulation of the immune system, thus contributing to allergic or autoimmune disease. ... 

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