Methodological uncertainties

These examples illustrate the power of proper ANN feature space optimization. In all the examples discussed, the limits of the type of information that could be gleaned from the Salmonella PyMAB spectra were probed. The PD-ANN s automated optimization removed the issue of methodological uncertainty and enabled a focus on questions of Py-MAB-MS spectral information content and its potential use for rapid strain ID. Question Does Py-MAB-MS data support Serovar classification Answer Yes. How about PFGE classification Yes. How about antibiotic resistance profile Answer Perhaps, if one first eliminates stronger contributions to spectral variation and then, by design and grouping, limits the possibilities to only a few classes. 

Methodological uncertainties For example, scientists have classified about 1.4 million species on our planet, which represents less than 5% of the estimated number of species currently living. Even for the least-abundant taxonomic groups, mammals and birds, the number of species reaches 4000 and 9000, respectively. The proportion of species that can be tested in toxicity studies is therefore a very small fraction of those that could be exposed. 

The uncertainties identified in connection with these conclusions include questions about the adequacy of the method used to calculate a MOS for bioaccumulative substances like Octa, as well as a similar methodological uncertainty linked to the current PEC/PNEC approach for secondary poisoning in terms of both the PEC and the PNEC (which could lead to an underestimation of risk). The risk assessment report also identifies a general uncertainty connected with the strength of the scientific basis for drawing conclusions on the current and future environmental risks of Octa. 

The analyses were performed on different days to take into account the day-to-day variability of the technique used. Care was taken to perform the measurements in the most repeatable way. The methodological uncertainty was determined by five replicate analyses of one reconstituted sample. 

Hallifax D, Houston JB. Methodological uncertainty in quantitative prediction of human hepatic clearance from in vitro experimental systems. Curr Drug Metab 2009 10(3) 307-321. 

Attempts to detect variations in agent response, which resulted in small safety margins and thus greater risks to experimental subjects, and the study of methodological uncertainties more generally, had been made both before and after Maddison s death. Seen from a certain perspective, these activities... 

Methodological uncertainty due to assumptions made with LCA parameters. 

The fraction 0.1% is chosen to be so low that individuals living near a nuclear plant should have no special concern because of the closeness. Uncertainties in the analysis of risk are not caused by the "quantitative methodology" but are highlighted by it. Uncertainty reduction will be achieved by methodological improvements mean values should be calculated. As a guideline for rcinilatory implementation, the following is recommended ... 

When using failure rate data for a CPQRA, the ideal situation is to have valid historical data from the identical equipment in the same application. In most cases, plant-specific data are unavailable or may carry a level of confidence that is too low to allow those data to be used without corroborating data. Risk analysts often overcome these problems by using generic failure rate data as surrogates for or supplements to plant-specific data. Because of the uncertainties inherent in risk analysis methodology, generic failure rate data are frequently adequate to identify the major risk contributors in a process or plant. 

Our concepts of petroleum reserves and resources and their measurements are changing to reflect the uncertainty associated with these terms. Petroleum reseiwes have been largely calculated deterministically (i.e. single point estimates with the assumption of certainty). In the past decade, reseiwe and resource calculations have incorporated uncertainty into their estimates using probabilistic methodologies. One of the questions now being addressed are such as how certain arc you that the rcsciwcs you estimate arc the actual reseiwes and what is the range of uncertainty associated with that estimate New techniques arc required to address the critical question of how much petroleum we have and under what conditions it can be developed. 

This chapter summarizes climate projections presented by the recent Fourth Assessment Report (AR4) of the IPCC, both for the global scale and for the so-called European and Mediterranean region. Besides the IPCC projections, other results regarding the Mediterranean area will be reviewed as well. The emphasis will be mostly placed on temperature and precipitation projections, while other variables, such as wind, solar radiation, or sea level, will not be commented in depth. Some attention will be paid to methodologies used to develop projections, and the corresponding uncertainties will be commented. In general, projections will be given for the end of the current century. 

It is essential that, with the use of evidence-based medicine to inform decisions in health care, the processes used in program development be as transparent as possible. Information about the limited evidence and inherent uncertainty should be disclosed and available for scrutiny, even within the software itself. In fact, in an attempt to maximize transparency, some have advocated open source development and publication of interactive software models [49, 50]. Certainly, details of methodologies, sources, and other techniques employed for development of the underlying models must be acknowledged. However, the proprietary nature of many of these programs must be taken into consideration and measures put into place to ensure confidentiality. Requested publication of all NIH-sponsored research online (in PubMed) [51] within a reasonable time frame after journal acceptance will help to ensure that these data are available in the public domain in short order. 

The considerably higher costs for operation and sample analysis of an event-based network currently preclude a higher sampling frequency. In addition, data from the networks are limited to wet deposition. Methodologies for determining dry deposition are subject to greater uncertainties, and can be more costly than wet deposition... 

---