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PubMed1993

Lack of total independence of uncertainty factors (UFs): implications for the size of the total uncertainty factor.

This paper assesses the fundamental assumption that multiple uncertainty factors (UFs) are independent of each other and therefore may be combined through a multiplicative scheme. It is argued that a lack of independence is seen in several cases such as that between the interindividual and less-than-lifetime UFs with respect to an age component and results in an error in double counting of UFs. The paper proposes revised UF values based on the concept of the relationship of independent and interdependent UFs. This uncertainty factor revision is then applied to a large number of contaminants for which EPA either has or has proposed MCLs or DWELs.

Age Factors↗
PubMed2006

Uncertainty of the thyroid dose conversion factor for inhalation intakes of 131I and its parametric uncertainty.

Inhalation exposures of 131I may occur in the physical form of a gas as well as a particulate. The physical characteristics pertaining to these different types of releases influence the intake and subsequent dose to an exposed individual. The thyroid dose received is influenced by the route through which 131I enters the body and its subsequent clearance, absorption and movement throughout the body. The radioactive iodine taken up in the gas-exchange tissues is cleared to other tissues or absorbed into the bloodstream of the individual and transferred to other organs. Iodine in the circulatory system is then taken up by the thyroid gland with resulting dose to that tissue. The magnitude of and uncertainty in the thyroid dose is important to the assessment of individuals exposed to airborne releases of radioiodine. Age- and gender-specific modelling parameters have resulted in significant differences between gas uptake, particulate deposition and inhalation dose conversion factors for each age and gender group. Inhalation dose conversion factors and their inherent uncertainty are markedly affected by the type of iodine intake. These differences are expected due to the modelling of particulate deposition versus uptake of gas in the respiratory tract. Inhalation dose estimates via iodine gases are very similar and separate classifications may not be necessarily based on this assessment.

Administration, Inhalation↗
PubMed1998

Hyteresis and Uncertainty: The Effect of Uncertainty on Delays to Exit Decisions.

The effects of feedback variability and the availability of information on exit decisions in a nonprofitable venture were investigated in a computer simulated marketing scenario. Half of subjects received feedback relatively low in variability and half of subjects received feedback substantially higher in variability. Half of subjects in each variability condition had the opportunity to purchase additional information regarding their investment. Subjects receiving feedback higher in variability delayed exit decisions longer, invested more often, and invested more resources than subjects receiving feedback lower in variability. Subjects with no opportunity to purchase information delayed exit decisions longer, invested more often, and invested more resources than subjects with the opportunity to purchase information. The results are consistent with Dixit's (1992) theory of uncertainty and hysteresis and indicate that an uncertain environment can affect whether a decision maker continues to invest when costs are higher than profits. Copyright 1998 Academic Press.

Journal Article↗
PubMed1989

Uncertainty in the estimation of benzene risks: application of an uncertainty taxonomy to risk assessments based on an epidemiology study of rubber hydrochloride workers.

This paper reviews 14 risk assessments that use the data from descriptions by Rinsky, Young, and co-workers of benzene-associated leukemias among a group of rubber hydrochloride workers in Ohio. The leukemogenic risks of benzene estimated in these assessments differ. The assessors use different assumptions (parameters, confounding factors, or formulas), which account for the differences in risk. The purpose of the review is to determine whether the major source of uncertainty in assessments of benzene risk arises from data, method, or concept. The results show that methodological differences dominate the other two potential sources with respect to impact on risk magnitude.

Benzene↗
PubMed2001

Uncertainty management: the influence of uncertainty salience on reactions to perceived procedural fairness.

On the basis of fairness heuristic theory, it is argued in this article that people especially need fairness when they are reminded about aspects of their lives that make them uncertain. It is therefore proposed that thinking about uncertainty should make fairness a more important issue to people. The findings of 3 experiments support this line of reasoning: Asking (vs. not asking) participants 2 questions that solicited their thoughts and feelings of being uncertain led to stronger effects of perceived procedural fairness on participants' affective reactions toward the way they were treated. It is argued that these findings suggest that fairness matters to people especially when they are trying to deal with things that make them uncertain. An implication of the current findings therefore may be that fairness is important to people because it gives them an opportunity to manage uncertain aspects of their lives.

Adult↗
PubMed1981

On the relativity and uncertainty of distance, time, and energy measurements by man. (1) Derivation of the Weber psychophysical law from the Heisenberg uncertainty principle applied to a superconductive biological detector. (2) The reverse derivation. (3) A human theory of relativity.

The Weber psychophysical law, which describes much experimental data on perception by man, is derived from the Heisenberg uncertainty principle on the assumption that human perception occurs by energy detection by superconductive microregions within man . This suggests that psychophysical perception by man might be considered merely a special case of physical measurement in general. The reverse derivation-i.e., derivation of the Heisenberg principle from the Weber law-may be of even greater interest. It suggest that physical measurements could be regarded as relative to the perceptions by the detectors within man. Thus one may develop a "human" theory of relativity that could have the advantage of eliminating hidden assumptions by forcing physical theories to conform more completely to the measurements made by man rather than to concepts that might not accurately describe nature.

Distance Perception↗
PubMed2005

The optimisation approach of ALARA in nuclear practice: an early application of the precautionary principle. Scientific uncertainty versus legal uncertainty.

The late health effects of exposure to low doses of ionising radiation are subject to scientific controversy: one view finds threats of high cancer incidence exaggerated, while the other view thinks the effects are underestimated. Both views have good scientific arguments in favour of them. Since the nuclear field, both industry and medicine have had to deal with this controversy for many decades. One can argue that the optimisation approach to keep the effective doses as low as reasonably achievable, taking economic and social factors into account (ALARA), is a precautionary approach. However, because of these stochastic effects, no scientific proof can be provided. This paper explores how ALARA and the Precautionary Principle are influential in the legal field and in particular in tort law, because liability should be a strong incentive for safer behaviour. This so-called "deterrence effect" of liability seems to evaporate in today's technical and highly complex society, in particular when dealing with the late health effects of low doses of ionising radiation. Two main issues will be dealt with in the paper: 1. How are the health risks attributable to "low doses" of radiation regulated in nuclear law and what lessons can be learned from the field of radiation protection? 2. What does ALARA have to inform the discussion of the Precautionary Principle and vice-versa, in particular, as far as legal sanctions and liability are concerned? It will be shown that the Precautionary Principle has not yet been sufficiently implemented into nuclear law.

Government Regulation↗
PubMed1977

Prior event uncertainty reduction under two different levels of time uncertainty of foreperiod duration in schizophrenia.

Schizophrenic and alcoholic Ss judged stimulus durations of .50 and .55 seconds. Stimulus was 1, 3 or 5 dark dots and was preceded by variable foreperiod duration of 1, 3 or 5 seconds. Judgment of stimulus duration was found to be a monotonically increasing function of both foreperiod duration and numerosity of dots. When pitch of sound, which functioned as a warning signal, was correlated with numerosity of dots, the monotonic relation between numerosity of dots and estimation of stimulus duration was eliminated for alcoholics, but not for schizophrenics, only when foreperiod duration was constant from trial to trial. The effect of prior information as to numerosity of dots was negligible for both schizophrenics and alcoholics when foreperiod duration was variable from trial to trial.

Adult↗
PubMed2005

The Blood Pressure "Uncertainty Range" - a pragmatic approach to overcome current diagnostic uncertainties (II).

A tremendous amount of scientific evidence regarding the physiology and physiopathology of high blood pressure combined with a sophisticated therapeutic arsenal is at the disposal of the medical community to counteract the overall public health burden of hypertension. Ample evidence has also been gathered from a multitude of large-scale randomized trials indicating the beneficial effects of current treatment strategies in terms of reduced hypertension-related morbidity and mortality.In spite of these impressive advances and, deeply disappointingly from a public health perspective, the real picture of hypertension management is overshadowed by widespread diagnostic inaccuracies (underdiagnosis, overdiagnosis) as well as by treatment failures generated by undertreatment, overtreatment, and misuse of medications.The scientific, medical and patient communities as well as decision-makers worldwide are striving for greatest possible health gains from available resources.A seemingly well-crystallised reasoning is that comprehensive strategic approaches must not only target hypertension as a pathological entity, but rather, take into account the wider environment in which hypertension is a major risk factor for cardiovascular disease carrying a great deal of our inheritance, and its interplay in the constellation of other, well-known, modifiable risk factors, i.e., attention is to be switched from one's "blood pressure level" to one's absolute cardiovascular risk and its determinants. Likewise, a risk/benefit assessment in each individual case is required in order to achieve best possible results.Nevertheless, it is of paramount importance to insure generalizability of ABPM use in clinical practice with the aim of improving the accuracy of a first diagnosis for both individual treatment and clinical research purposes. Widespread adoption of the method requires quick adjustment of current guidelines, development of appropriate technology infrastructure and training of staff (i.e., education, decision support, and information systems for practitioners and patients). Progress can be achieved in a few years, or in the next 25 years.

Journal Article↗