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PubMed1990

Information theory and collative motivation: incentive value of uncertainty, variety, and novelty for children.

We tested the applicability of concepts and measures from information theory to studies of the development and operation of collative motivation. Three variables nominated by Berlyne as potential motivators of information seeking--uncertainty, variety, and novelty--were put into correspondence with three informational theoretic measures--average uncertainty in bits, number of possible outcomes, and outcome probability--to investigate the incentive properties of each variable for first and fourth graders. Increasing bit levels of uncertainty by adding alternatives to the set of possible outcomes was generally positively related to cover choices; however, increasing bit values by varying outcome probabilities from unequal to equal had no effect on choice. Without uncertainty, variety provided a weak source of collative motivation, systematically related to the choice of the transparent cover only for the older children when rewards occurred equally frequently. In contrast, the transparent cover was chosen significantly more frequently when the outcome probability of the associated reward was low. We obtained developmental stability in motivational effects except for variety operating in the absence of uncertainty.

Arousal↗

PubMedDate not supplied

Uncertainty and adjustment during radiotherapy.

The relationships among uncertainty, hope, symptom severity, control preference, and psychosocial adjustment were examined in persons having radiotherapy for cancer. After 15 days of radiotherapy, both uncertainty (17%) and hope (16%) explained significant amounts of the variance in adjustment. At the end of treatment, uncertainty (18%), hope (11%), and symptom severity (7%) all significantly increased the explained variance in adjustment. Greater uncertainty and less hope were associated with more adjustment problems; symptom severity increased the explanation of adjustment difficulty at treatment completion. There was no evidence that uncertainty had positive effects in this sample. Findings also showed that control preference was unrelated to the concepts of interest in this sample.

Adaptation, Psychological↗

PubMed1995

Adult uncertainty in illness: a critical review of research.

Nursing interest in the uncertainty associated with life-threatening illnesses and their treatment technology is growing. Nurse investigators have begun to study variables that precede and influence this uncertainty, as well as how persons appraise, cope with, and adapt to uncertainty. This paper reviews and examines data from both quantitative and qualitative nursing studies of adult illness-related uncertainty published after 1980. Findings demonstrate that uncertainty is a pervasive stressful accompaniment of illness and its treatment that influences persons' coping and adaptive responses. Implications for nursing practice and future research are explored.

Adaptation, Psychological↗

PubMed1993

Different ways of modeling spatial-frequency uncertainty in visual signal detection.

Inferior human signal-detection behavior compared with that of ideal observers has been explained by intrinsic uncertainty of the human observer with respect to certain signal parameters. One way to model this uncertainty is to assume that the observer simultaneously monitors multiple channels, corresponding to possible parameters. However, it is also conceivable to assume that an observer, uncertain about which channel to monitor, chooses a suboptimally tuned single filter. Finally, uncertainty may also cause the filter underlying a single channel to broaden. In this paper these different models are investigated with respect to spatial-frequency uncertainty for matched filters detecting Gabor signals. All three mechanisms predict a decrease in detection performance. However, it is shown that the resulting psychometric functions are different. While the slopes increase with uncertainty for the multiple-channel models, they decrease for a randomly chosen single channel. Broadening a single filter leads to parallel psychometric functions.

Humans↗

PubMed1995

Studying the effect of clinical uncertainty on physicians' decision-making using ILIAD.

The influence of uncertainty on physicians' practice behavior is not well understood. In this research, ILIAD, a diagnostic expert system, has been used to study physicians' responses to uncertainty and how their responses affected clinical performance. The simulation mode of ILIAD was used to standardize the presentation and scoring of two cases to 46 residents in emergency medicine, internal medicine, family practice and transitional medicine at Methodist Hospital of Indiana. A questionnaire was used to collect additional data on how physicians respond to clinical uncertainty. A structural equation model was developed, estimated, and tested. The results indicate that stress that physicians experience in dealing with clinical uncertainty has a negative effect on their clinical performance. Moreover, the way that physicians respond to uncertainty has positive and negative effects on their performance. Open discussions with patients about clinical decisions and the use of practice guidelines improves performance. However, when the physician's clinical decisions are influenced by patient demands or their peers, their performance scores decline.

Clinical Competence↗

PubMed1997

Quality of life, hope, and uncertainty of cardiac patients and their spouses before coronary artery bypass surgery.

The relationships among quality of life, uncertainty, and hope for 21 patients and their spouses before bypass surgery were examined in this study. The instruments used included: Ferrans' and Powers' Quality of Life Index, Mishel's Uncertainty in Illness Scale, and the Herth Hope Index. Greater uncertainty was associated with lower quality of life and hope scores for patients and spouses. Spouses were more uncertain about the patients' cardiac disease and had higher quality of life scores than the patients. Female patients had more uncertainty about their disease. Patients with poor left ventricle function had lower quality of life. Implications for practice include the need to incorporate the spouse into the plan of care. Also, the presence of uncertainty in the waiting period for surgery for both patients and their spouses, and its negative association with quality of life, reinforces the importance of pre-admission intervention with this population.

Adult↗

PubMed1997

Functional uncertainty, aging and memory processes during sleep.

Disorganized sleep patterns, can be found both during normal development and in pathological conditions. Aging could also be accompanied by a disorganization of the night sleep episode; sleep could be interrupted by spontaneous awakening, sleep cycle could be shortened or incomplete, sleep states modified. These patterns suggest an inability to sustain a stable condition, i.e. a condition of functional uncertainty. Biological and cognitive implications of functional uncertainty conditions are discussed. In particular, the hypothesis has been put forward that disturbances of sleep could have a detrimental role on memory. Recent results obtained in our lab support this hypothesis: recall is correlated with NREM-REM cycles proportion. Future research should ascertain the role of the functional uncertainty with respect to the kind of memory being involved during sleep, and establish how much and for which cognitive processes (including those involved in dream production) the inability to sustain a steady condition impairs the functioning during sleep. The duration of the functional uncertainty condition is also important. The long-term study of the link between functional uncertainty and cognitive resources, could be important for the understanding of the night life and for an adequate treatment of patients.

Adult↗

PubMed2006

Uncertainty of illness relationships with mental health and coping processes in fibromyalgia patients.

Fibromyalgia syndrome (FMS) is a chronic musculoskeletal pain condition poorly understood in terms of etiology and treatment by both physicians and patients. This condition of "uncertainty of illness" was examined as a variable involved in the adjustment of FMS patients, relating it to their depression, anxiety, affect, and coping styles. Fifty-one community-residing FMS patients provided self-report information on subsets of adjustment variables. Both cross-sectional and more dynamic longitudinal analyses showed that illness uncertainty was significantly associated with anxiety, negative affect, and avoidant and passive coping. Its positive relationship with depression was eliminated when a control variable, pain helplessness, was included as a covariate. Longitudinally, illness uncertainty interacted with interpersonally stressful daily events in predicting reports of reduced positive affect, suggesting that illness uncertainty acts as a risk factor for affective disturbances during stressful times. Implications of these results for therapeutic interventions are discussed.

Adaptation, Psychological↗

PubMed2006

Uncertainty and the ethics of clinical trials.

A probabilistic explication is offered of equipoise and uncertainty in clinical trials. In order to be useful in the justification of clinical trials, equipoise has to be interpreted in terms of overlapping probability distributions of possible treatment outcomes, rather than point estimates representing expectation values. Uncertainty about treatment outcomes is shown to be a necessary but insufficient condition for the ethical defensibility of clinical trials. Additional requirements are proposed for the nature of that uncertainty. The indecisiveness of our criteria for cautious decision-making under uncertainty creates the leeway that makes clinical trials defensible.

Clinical Trials as Topic↗

PubMed2006

Question-based assessments of delay discounting: do respondents spontaneously incorporate uncertainty into their valuations for delayed rewards?

This research was designed to determine if, and to what extent, participants incorporate uncertainty into their valuations for delayed rewards when completing measures of delay discounting, even though uncertainty is not specified in the delay-discounting questions. Twenty-four adolescent participants completed a question-based measure of delay discounting and immediately following answered questions about perceived certainties of receiving the delayed rewards. Results showed that respondents rated the delayed rewards as increasingly uncertain with longer delays. Also, ratings of uncertainty were correlated with rate of delay discounting (r=0.55). These findings suggest participants automatically evaluate delayed rewards as uncertain when using this assessment procedure. The current finding may hold important implications for future addiction research in interpreting why addicted persons often discount more by delay than non-addicted controls, i.e., delay to reward or uncertainty about delayed rewards?

Adolescent↗

PubMed2004

The effects of uncertainty in error monitoring on associated ERPs.

A series of experiments were conducted to address the effect of uncertainty regarding performance for predicting the likelihood of a correct-response negativity (CRN) in addition to error-related negativity (ERN). In Study 1, 18 healthy young adults completed letter discrimination tasks during single and dual attention conditions designed to manipulate response certainty. In the second study, the same participants completed easy and difficult tone discrimination tasks designed to influence stimulus certainty. In the third study, task difficulty was manipulated to produce different error rates without altering certainty. Studies 1 and 2 indicated that error and correct responses are processed more similarly when uncertainty is present (i.e., ERN approximately CRN). Furthermore, uncertainty was associated with attenuation of the ERN and enhancement of the CRN, consistent with an error detection hypothesis. Study 3 indicated that task difficulty alone does not influence the ERN or likelihood of a CRN. These results offer support for the error detection account of the ERN and establish the role of uncertainty in predicting the CRN, as postulated by .

Acoustic Stimulation↗

PubMed2004

Uncertainty analysis of parameters for modeling the transfer and fate of benzo(a)pyrene in Tianjin wastewater irrigated areas.

A Monte Carlo simulation for uncertainty analysis of three key parameters (local coal consumption rate Q(1L), dry deposition velocity of aerosol particulate Kp and biodegradation rate of benzo(a)pyrene in soil and sediment K(R3)) was conducted in this study. Results of the simulation indicate that the three parameters were influenced by uncertainty and that all equilibrium concentrations in the four bulk compartments and various sub-compartments were log-normally distributed. However, the results also indicated that among the six primary transfer fluxes, erosion associated with solids in soil and deposition associated with solids in water, along with output from sewers were also log-normally distributed, while deposition from air to soil and biodegradation in soil and sediment followed normal distributions. The effect of uncertainty on the model results of the three key parameters was derived using a comparison of upper and lower of confidence interval boundaries at the 95% level of confidence. The results reveal that uncertainty in the key parameters had a more significant influence on equilibrium concentrations of the chemical in the bulk compartments of soil and sediment than on concentrations in the other two bulk compartments, various sub-compartments and the six predominant transfer fluxes.

Benzo(a)pyrene↗

PubMed2005

Uncertainty in biokinetic parameters on bioremediation: health risks and economic implications.

Human health risk assessment is one of the rapidly evolving tools used in the management of contaminated aquifers. Health risk assessments have been traditionally based on the point estimate approach. Due to the uncertainty and variability inherent in subsurface properties and exposed human population characteristics, probabilistic risk assessment is becoming widely accepted. This study is focused on understanding the uncertainty in biokinetic parameters in describing biodegradation under natural and enhanced remediation conditions. The uncertain parameters considered in this work are key biokinetic parameters and the uncertainty is assessed using the predicted receptor maximum concentration, maximum of 30-year average concentration, time to reach maximum concentration, maximum mass of decay, and the time for maximum decay. The results of this analysis were extended to health risk assessment and risk-based economic analysis. The paper discusses the approach and methodology adopted in this study and the implication of uncertainty of key parameters on decision-relevant information.

Biodegradation, Environmental↗

PubMed2005

Adequate margins for random setup uncertainties in head-and-neck IMRT.

PURPOSE: To investigate the effect of random setup uncertainties on the highly conformal dose distributions produced by intensity-modulated radiotherapy (IMRT) for clinical head-and-neck cancer patients and to determine adequate margins to account for those uncertainties. METHODS AND MATERIALS: We have implemented in our clinical treatment planning system the possibility of simulating normally distributed patient setup displacements, translations, and rotations. The planning CT data of 8 patients with Stage T1-T3N0M0 oropharyngeal cancer were used. The clinical target volumes of the primary tumor (CTV(primary)) and of the lymph nodes (CTV(elective)) were expanded by 0.0, 1.5, 3.0, and 5.0 mm in all directions, creating the planning target volumes (PTVs). We performed IMRT dose calculation using our class solution for each PTV margin, resulting in the conventional static plans. Then, the system recalculated the plan for each positioning displacement derived from a normal distribution with sigma = 2 mm and sigma = 4 mm (standard deviation) for translational deviations and sigma = 1 degrees for rotational deviations. The dose distributions of the 30 fractions were summed, resulting in the actual plan. The CTV dose coverage of the actual plans was compared with that of the static plans. RESULTS: Random translational deviations of sigma = 2 mm and rotational deviations of sigma = 1 degrees did not affect the CTV(primary) volume receiving 95% of the prescribed dose (V(95)) regardless of the PTV margin used. A V(95) reduction of 3% and 1% for a 0.0-mm and 1.5-mm PTV margin, respectively, was observed for sigma = 4 mm. The V(95) of the CTV(elective) contralateral was approximately 1% and 5% lower than that of the static plan for sigma = 2 mm and sigma = 4 mm, respectively, and for PTV margins <5.0 mm. An additional reduction of 1% was observed when rotational deviations were included. The same effect was observed for the CTV(elective) ipsilateral but with smaller dose differences than those for the contralateral side. The effect of the random uncertainties on the mean dose to the parotid glands was not significant. The maximal dose to the spinal cord increased by a maximum of 3 Gy. CONCLUSIONS: The margins to account for random setup uncertainties, in our clinical IMRT solution, should be 1.5 mm and 3.0 mm in the case of sigma = 2 mm and sigma = 4 mm, respectively, for the CTV(primary). Larger margins (5.0 mm), however, should be applied to the CTV(elective), if the goal of treatment is a V(95) value of at least 99%.

Head and Neck Neoplasms↗

PubMed2006

Uncertainty assessment of contaminant plume length estimates in heterogeneous aquifers.

The Virtual Aquifer approach is used in this study to assess the uncertainty involved in the estimation of contaminant plume lengths in heterogeneous aquifers. Contaminant plumes in heterogeneous two-dimensional conductivity fields and subject to first order and Michaelis-Menten (MM) degradation kinetics are investigated by the center line method. First order degradation rates and plume lengths are estimated from point information obtained along the plume center line. Results from a Monte-Carlo investigation show that the estimated rate constant is highly uncertain and biased towards overly high values. Uncertainty and bias amplify with increasing heterogeneity up to maximum values of one order of magnitude. Calculated plume lengths reflect this uncertainty and bias. On average, plume lengths are estimated to about 50% of the true plume length. When plumes subject to MM degradation kinetics are investigated by using a first order rate law, an additional error is introduced and uncertainty as well as bias increase, causing plume length estimates to be less than 40% of the true length. For plumes with MM degradation kinetics, therefore, a regression approach is used which allows the determination of the MM parameters from center line data. Rate parameters are overestimated by a factor of two on average, while plume length estimates are about 80% of the true length. Plume lengths calculated using the MM parameters are thus closer to the correct length, as compared to the first order approximation. This approach is therefore recommended if field data collected along the center line of a plume give evidence of MM kinetics.

Computer Simulation↗

PubMed2005

A distance-based uncertainty analysis approach to multi-criteria decision analysis for water resource decision making.

The choice among alternative water supply sources is generally based on the fundamental objective of maximising the ratio of benefits to costs. There is, however, a need to consider sustainability, the environment and social implications in regional water resources planning, in addition to economics. In order to achieve this, multi-criteria decision analysis (MCDA) techniques can be used. Various sources of uncertainty exist in the application of MCDA methods, including the selection of the MCDA method, elicitation of criteria weights and assignment of criteria performance values. The focus of this paper is on the uncertainty in the criteria weights. Sensitivity analysis can be used to analyse the effects of uncertainties associated with the criteria weights. Two existing sensitivity methods are described in this paper and a new distance-based approach is proposed which overcomes limitations of these methods. The benefits of the proposed approach are the concurrent alteration of the criteria weights, the applicability of the method to a range of MCDA techniques and the identification of the most critical criteria weights. The existing and proposed methods are applied to three case studies and the results indicate that simultaneous consideration of the uncertainty in the criteria weights should be an integral part of the decision making process.

Conservation of Natural Resources↗

PubMed2026

Uncertainty and information management for Lynch syndrome in a genomic screening cohort: Connections to clinical engagement.

OBJECTIVE: Lynch syndrome (LS) is a common hereditary cancer predisposition syndrome. This study explores how individuals learning about LS-related cancer risk through a population genomic screening program appraise, reappraise, and manage uncertainty and engage in medical management. METHODS: We recruited participants with an LS result from a population genomic screening study, purposively sampling based on the characteristics of sex, age, LS gene, and family history of cancer. Semi-structured interviews and chart reviews focused on participants' experiences of learning about the LS result and making management decisions. Thematic analysis and heatmapping were used to explore participant characteristics related to uncertainty management and clinical engagement. RESULTS: Seventeen participants completed interviews, describing uncertainty discrepancies or ambivalent appraisals. Most participants who appraised their LS risk as a threat had high clinical engagement. All participants who had lower clinical engagement received misinformation, had little support from clinicians, or had misunderstandings about LS. CONCLUSION: Accurate information from trusted sources is critical to support uncertainty management and subsequent engagement in clinical risk management choices. PRACTICE IMPLICATIONS: Ensuring primary care providers have the information and tools to provide patients with accurate information may support recommended clinical engagement, thereby improving health outcomes for this population.

Clinical Engagement↗

PubMed2005

Managing uncertainty around HIV/AIDS in an urban setting: private medical providers and their patients in Pune, India.

Changing epidemiological patterns and the advent of new rapid diagnostic technologies and therapies have created considerable uncertainty for providers working in HIV. In India, the demand for HIV care is increasingly being met by private practitioners (PPs), yet little is known about how they deal with the challenges of managing HIV patients. To explore HIV management practices in the private medical sector, a survey was conducted with 215PPs in Pune, India, followed by in-depth interviews focusing on the social context of practice among a sub-set of 27PPs. Drawing primarily on interview data, this paper illustrates a number of uncertainties that underlie the reported actions of providers in a competitive medical market. PPs perceive HIV as a 'new' and challenging disease for which they lack adequate knowledge and skills. Combined with the perceived high cost and complexity of antiretroviral treatment, preconceptions about HIV patients' social, financial and mental capacity lead to highly individualistic management practices. While these fall short of clinical 'best practice' guidelines, they reflect adaptive responses to the wider uncertainties surrounding HIV care in urban India. By highlighting contextual issues in PPs' management of HIV patients, the paper suggests the need to explicitly acknowledge the social, moral and economic bases of uncertainty beyond the clinical setting.

Antiretroviral Therapy, Highly Active↗