Psychological methods of subjective risk estimates

International Nuclear Information System (INIS)

Zimolong, B.

1980-01-01

Reactions to situations involving risks can be divided into the following parts/ perception of danger, subjective estimates of the risk and risk taking with respect to action. Several investigations have compared subjective estimates of the risk with an objective measure of that risk. In general there was a mis-match between subjective and objective measures of risk, especially, objective risk involved in routine activities is most commonly underestimated. This implies, for accident prevention, that attempts must be made to induce accurate subjective risk estimates by technical and behavioural measures. (orig.) [de

Screening effects on thyroid cancer risk estimates for populations affected by the Chernobyl accident

International Nuclear Information System (INIS)

Jacob, P.; Kaiser, J. C.; Vavilov, S.E.; Bogdanova, T.; Tronko, N. D.

2004-01-01

Simulation calculations are performed in order to explore the ecological bias in studies as they are performed with settlement specific data in the aftemath of the Chernobyl accident. Based on methods, that were developed by Lubin for exploring the ecologic bias due to smoking in indoor radon studies of lung cancer, the influence of the introduction of ultrasound devices and enhanced medical surveillance on the detection and reporting of thyroid cancer cases was investigated. Calculations were performed by simulating thyroid doses of one million children in a total of 744 settlements and assuming a linear dependence of the risk on dose and various scenarios of the screening. The dose distributions simulate the distributions similar to those used in previous ecologic studies of the thyroid cancer risk in Ukraine after the Chernobyl accident. The ecologic bias was defined as the ratio of risk coefficients derived from an ecological study to the corresponding risk factor in the underlying risl model. the ecologic bias was estimated for each of the screening scenarios. Analytical equations were derived that allow the exact numerical compuation of the bias which is determined by covariance terms between the increased detection and reporting on one side and thyroid dose values (individual and averaged for the settlements) on the other side. Nested in th epopulation data, a cohort study was simulated with 10 000 individuals and an average thyroid dose of 0.3 Gy. the present study underlines the different scopes of the ecologic and cohort study designs perfomed in the aftermed of the Chernobyl accident. Whereas the ecologic studies give an estimate of the excess thyroid cancer risks per unit dose under the conditions of a health care system as it is typical for the affected countries after the Chernobyl accident, the cohort study gives risk estimates within a well screened cohort. Due to the strong screening effects, excess absoulte risks in the ecological study cohort are

Development of cancer risk estimates from epidemiologic studies

International Nuclear Information System (INIS)

Webster, E.W.

1983-01-01

Radiation risk estimates may be made for an increase in mortality from, or for an increase in incidence of, particular types of disease. For both endpoints, two numerical systems of risk expression are used: the absolute risk system (usually the excess deaths or cases per million persons per year per rad), and the relative risk system (usually excess deaths or cases per year per rad expressed as a percentage of those normally expected). Risks may be calculated for specific age groups or for a general population. An alternative in both risk systems is the estimation of cumulative of lifetime risk rather than annual risk (e.g. in excess deaths per million per rad over a specified long period including the remainder of lifespan). The derivation of both absolute and relative risks is illustrated by examples. The effects on risk estimates of latent period, follow-up time, age at exposure and age standardization within dose groups are illustrated. The dependence of the projected cumulative (lifetime) risk on the adoption of a constant absolute risk or constant relative risk is noted. The use of life-table data in the adjustment of cumulative risk for normal mortality following single or annual doses is briefly discussed

Uncertainty in exposure of underground miners to radon daughters and the effect of uncertainty on risk estimates

International Nuclear Information System (INIS)

1989-10-01

Studies of underground miners provide the principal basis for assessing the risk from radon daughter exposure. An important problem in all epidemiological studies of underground miners is the reliability of the estimates of the miners' exposures. This study examines the various sources of uncertainty in exposure estimation for the principal epidemiologic studies reported in the literature including the temporal and spatial variability of radon sources and, with the passage of time, changes to both mining methods and ventilation conditions. Uncertainties about work histories and the role of other hard rock mining experience are also discussed. The report also describes two statistical approaches, both based on Bayesian methods, by which the effects on the estimated risk coefficient of uncertainty in exposure (WLM) can be examined. One approach requires only an estimate of the cumulative WLM exposure of a group of miners, an estimate of the number of (excess) lung cancers potentially attributable to that exposure, and a specification of the uncertainty about the cumulative exposure of the group. The second approach is based on a linear regression model which incorporates errors (uncertainty) in the independent variable (WLM) and allows the dependent variable (cases) to be Poisson distributed. The method permits the calculation of marginal probability distributions for either slope (risk coefficient) or intercept. The regression model approach is applied to several published data sets from epidemiological studies of miners. Specific results are provided for each data set and apparent differences in risk coefficients are discussed. The studies of U.S. uranium miners, Ontario uranium miners and Czechoslovakian uranium miners are argued to provide the best basis for risk estimation at this time. In general terms, none of the analyses performed are inconsistent with a linear exposure-effect relation. Based on analyses of the overall miner groups, the most likely ranges

Summary of the BEIR V committee's estimates of genetic risks

International Nuclear Information System (INIS)

Grahn, D.

1990-01-01

The Committee on the Biological Effects of Ionizing Radiations (BEIR V) was constituted in late 1986 to conduct a comprehensive review of the biological effects of ionizing radiations focusing on information reported since the conclusion of the 1980 BEIR study, and to provide new estimates of the risks of genetic and somatic effects in humans due to low-level exposures of ionizing radiation. The Committee preferred the doubling-dose method of genetic risk estimation over the direct method. Data from animal (mouse) studies provide a median value of 100 to 114 cGy for long-term low dose rate exposure doubling doses. These values are lower than the median from human studies. The BEIR Committee believed that a doubling dose of 100 cGy would be a prudent value leading to conservative estimates. The estimated risks themselves are not much different from those generated by previous BEIR committees, UNSCEAR, and other published estimates. The Committee estimates that between 100 and 200 added cases per million live births will be observed at genetic equilibrium if the population is exposed each generation to a dose of 0.01 Sv (1 rem). Nearly half ware attributed to clinically mild dominant defects, and the balance to congenital abnormalities. (L.L.) (2 tabs.)

Exposure Estimation and Interpretation of Occupational Risk: Enhanced Information for the Occupational Risk Manager

Science.gov (United States)

Waters, Martha; McKernan, Lauralynn; Maier, Andrew; Jayjock, Michael; Schaeffer, Val; Brosseau, Lisa

2015-01-01

The fundamental goal of this article is to describe, define, and analyze the components of the risk characterization process for occupational exposures. Current methods are described for the probabilistic characterization of exposure, including newer techniques that have increasing applications for assessing data from occupational exposure scenarios. In addition, since the probability of health effects reflects variability in the exposure estimate as well as the dose-response curve—the integrated considerations of variability surrounding both components of the risk characterization provide greater information to the occupational hygienist. Probabilistic tools provide a more informed view of exposure as compared to use of discrete point estimates for these inputs to the risk characterization process. Active use of such tools for exposure and risk assessment will lead to a scientifically supported worker health protection program. Understanding the bases for an occupational risk assessment, focusing on important sources of variability and uncertainty enables characterizing occupational risk in terms of a probability, rather than a binary decision of acceptable risk or unacceptable risk. A critical review of existing methods highlights several conclusions: (1) exposure estimates and the dose-response are impacted by both variability and uncertainty and a well-developed risk characterization reflects and communicates this consideration; (2) occupational risk is probabilistic in nature and most accurately considered as a distribution, not a point estimate; and (3) occupational hygienists have a variety of tools available to incorporate concepts of risk characterization into occupational health and practice. PMID:26302336

Residual risk over-estimated

International Nuclear Information System (INIS)

Anon.

1982-01-01

The way nuclear power plants are built practically excludes accidents with serious consequences. This is attended to by careful selection of material, control of fabrication and regular retesting as well as by several safety systems working independently. But the remaining risk, a 'hypothetic' uncontrollable incident with catastrophic effects is the main subject of the discussion on the peaceful utilization of nuclear power. The this year's 'Annual Meeting on Nuclear Engineering' in Mannheim and the meeting 'Reactor Safety Research' in Cologne showed, that risk studies so far were too pessimistic. 'Best estimate' calculations suggest that core melt-down accidents only occur if almost all safety systems fail, that accidents take place much more slowly, and that the release of radioactive fission products is by several magnitudes lower than it was assumed until now. (orig.) [de

Effect of Risk of Bias on the Effect Size of Meta-Analytic Estimates in Randomized Controlled Trials in Periodontology and Implant Dentistry

Science.gov (United States)

Faggion, Clovis Mariano; Wu, Yun-Chun; Scheidgen, Moritz; Tu, Yu-Kang

2015-01-01

Background Risk of bias (ROB) may threaten the internal validity of a clinical trial by distorting the magnitude of treatment effect estimates, although some conflicting information on this assumption exists. Objective The objective of this study was evaluate the effect of ROB on the magnitude of treatment effect estimates in randomized controlled trials (RCTs) in periodontology and implant dentistry. Methods A search for Cochrane systematic reviews (SRs), including meta-analyses of RCTs published in periodontology and implant dentistry fields, was performed in the Cochrane Library in September 2014. Random-effect meta-analyses were performed by grouping RCTs with different levels of ROBs in three domains (sequence generation, allocation concealment, and blinding of outcome assessment). To increase power and precision, only SRs with meta-analyses including at least 10 RCTs were included. Meta-regression was performed to investigate the association between ROB characteristics and the magnitudes of intervention effects in the meta-analyses. Results Of the 24 initially screened SRs, 21 SRs were excluded because they did not include at least 10 RCTs in the meta-analyses. Three SRs (two from periodontology field) generated information for conducting 27 meta-analyses. Meta-regression did not reveal significant differences in the relationship of the ROB level with the size of treatment effect estimates, although a trend for inflated estimates was observed in domains with unclear ROBs. Conclusion In this sample of RCTs, high and (mainly) unclear risks of selection and detection biases did not seem to influence the size of treatment effect estimates, although several confounders might have influenced the strength of the association. PMID:26422698

Space Radiation Heart Disease Risk Estimates for Lunar and Mars Missions

Science.gov (United States)

Cucinotta, Francis A.; Chappell, Lori; Kim, Myung-Hee

2010-01-01

The NASA Space Radiation Program performs research on the risks of late effects from space radiation for cancer, neurological disorders, cataracts, and heart disease. For mortality risks, an aggregate over all risks should be considered as well as projection of the life loss per radiation induced death. We report on a triple detriment life-table approach to combine cancer and heart disease risks. Epidemiology results show extensive heterogeneity between populations for distinct components of the overall heart disease risks including hypertension, ischaemic heart disease, stroke, and cerebrovascular diseases. We report on an update to our previous heart disease estimates for Heart disease (ICD9 390-429) and Stroke (ICD9 430-438), and other sub-groups using recent meta-analysis results for various exposed radiation cohorts to low LET radiation. Results for multiplicative and additive risk transfer models are considered using baseline rates for US males and female. Uncertainty analysis indicated heart mortality risks as low as zero, assuming a threshold dose for deterministic effects, and projections approaching one-third of the overall cancer risk. Medan life-loss per death estimates were significantly less than that of solid cancer and leukemias. Critical research questions to improve risks estimates for heart disease are distinctions in mechanisms at high doses (>2 Gy) and low to moderate doses (<2 Gy), and data and basic understanding of radiation doserate and quality effects, and individual sensitivity.

Quantifying IT estimation risks

NARCIS (Netherlands)

Kulk, G.P.; Peters, R.J.; Verhoef, C.

2009-01-01

A statistical method is proposed for quantifying the impact of factors that influence the quality of the estimation of costs for IT-enabled business projects. We call these factors risk drivers as they influence the risk of the misestimation of project costs. The method can effortlessly be

Effect of Antihypertensive Therapy on SCORE-Estimated Total Cardiovascular Risk: Results from an Open-Label, Multinational Investigation—The POWER Survey

Directory of Open Access Journals (Sweden)

Guy De Backer

2013-01-01

Full Text Available Background. High blood pressure is a substantial risk factor for cardiovascular disease. Design & Methods. The Physicians' Observational Work on patient Education according to their vascular Risk (POWER survey was an open-label investigation of eprosartan-based therapy (EBT for control of high blood pressure in primary care centers in 16 countries. A prespecified element of this research was appraisal of the impact of EBT on estimated 10-year risk of a fatal cardiovascular event as determined by the Systematic Coronary Risk Evaluation (SCORE model. Results. SCORE estimates of CVD risk were obtained at baseline from 12,718 patients in 15 countries (6504 men and from 9577 patients at 6 months. During EBT mean (±SD systolic/diastolic blood pressures declined from 160.2 ± 13.7/94.1 ± 9.1 mmHg to 134.5 ± 11.2/81.4 ± 7.4 mmHg. This was accompanied by a 38% reduction in mean SCORE-estimated CVD risk and an improvement in SCORE risk classification of one category or more in 3506 patients (36.6%. Conclusion. Experience in POWER affirms that (a effective pharmacological control of blood pressure is feasible in the primary care setting and is accompanied by a reduction in total CVD risk and (b the SCORE instrument is effective in this setting for the monitoring of total CVD risk.

Effect of Antihypertensive Therapy on SCORE-Estimated Total Cardiovascular Risk: Results from an Open-Label, Multinational Investigation—The POWER Survey

Science.gov (United States)

De Backer, Guy; Petrella, Robert J.; Goudev, Assen R.; Radaideh, Ghazi Ahmad; Rynkiewicz, Andrzej; Pathak, Atul

2013-01-01

Background. High blood pressure is a substantial risk factor for cardiovascular disease. Design & Methods. The Physicians' Observational Work on patient Education according to their vascular Risk (POWER) survey was an open-label investigation of eprosartan-based therapy (EBT) for control of high blood pressure in primary care centers in 16 countries. A prespecified element of this research was appraisal of the impact of EBT on estimated 10-year risk of a fatal cardiovascular event as determined by the Systematic Coronary Risk Evaluation (SCORE) model. Results. SCORE estimates of CVD risk were obtained at baseline from 12,718 patients in 15 countries (6504 men) and from 9577 patients at 6 months. During EBT mean (±SD) systolic/diastolic blood pressures declined from 160.2 ± 13.7/94.1 ± 9.1 mmHg to 134.5 ± 11.2/81.4 ± 7.4 mmHg. This was accompanied by a 38% reduction in mean SCORE-estimated CVD risk and an improvement in SCORE risk classification of one category or more in 3506 patients (36.6%). Conclusion. Experience in POWER affirms that (a) effective pharmacological control of blood pressure is feasible in the primary care setting and is accompanied by a reduction in total CVD risk and (b) the SCORE instrument is effective in this setting for the monitoring of total CVD risk. PMID:23997946

Estimation, assessment and management of risks

International Nuclear Information System (INIS)

Reinoehl-Kompa, S.

2005-01-01

After the introductory lectures the closed conference divided into sessions on the estimation, assessment and management of risks. This review article summarises some of the central issues which were addressed in the discussions held during the closed conference and which may be of significance for the future work of the ''Radiation Risk'' Committee within the Radiation Protection Commission. Fundamental difficulties still persist in the implementation of risk quantities within the concepts of radiation protection (lectures by Breckow and Kiefer). Some of these difficulties have to do with the definition of dose quantities, in particular with the one most central to radiation protection, the effective dose. In the field of sparsely ionizing radiation attention was focused on two main topics, namely the risk of acquiring thyroid cancer in association with the Chernobyl desaster and analyses of new mortality data on the survivors of the nuclear bomb attacks on Hiroshima and Nagasaki. In the area of lung cancer risk from radon exposure, attention was focused on indoor exposure and the cohort study on bismuth miners. The body of knowledge that has accumulated on the risk of acquiring cancer through UV radiation takes a special position within the wider field of risks associated with nonionizing radiation, since much has already been achieved towards identifying the action mechanisms involved here. Since skin cancer shows the highest increments in incidence of all types of cancer, estimating the risk of acquiring skin cancer through UV radiation will be an important issue in future. One of the tasks of risk management is to translate the results of risk assessment into action. One task of particular importance in this regard is ''risk communication'', the problems surrounding which were illuminated from different perspectives in various contributions

Occupational and consumer risk estimates for nanoparticles emitted by laser printers

International Nuclear Information System (INIS)

Haenninen, Otto; Brueske-Hohlfeld, Irene; Loh, Miranda; Stoeger, Tobias; Kreyling, Wolfgang; Schmid, Otmar; Peters, Annette

2010-01-01

Several studies have reported laser printers as significant sources of nanosized particles ( -1 ; particle number 1.1-3.1 x 10 9 d -1 ) were estimated to correspond to 4-13 (mass) or 12-34 (number) deaths per million persons exposed on the basis of epidemiological risk estimates for ambient particles. These risks are higher than the generally used definition of acceptable risk of 1 x 10 -6 , but substantially lower than the estimated risks due to ambient particles. Toxicological studies on ambient particles revealed consistent values for lowest observed effect levels (LOELs) which were converted into equivalent daily uptakes using allometric scaling. These LOEL uptakes were by a factor of about 330-1,000 (mass) and 1,000-2,500 (particle surface area) higher than estimated uptakes from printers. This toxicological assessment would indicate no significant health risks due to printer particles. Finally, our study suggests that particle number (not mass) and mass (not surface area) are the most conservative risk metrics for the epidemiological and toxicological risks presented here, respectively.

Variance computations for functional of absolute risk estimates.

Science.gov (United States)

Pfeiffer, R M; Petracci, E

2011-07-01

We present a simple influence function based approach to compute the variances of estimates of absolute risk and functions of absolute risk. We apply this approach to criteria that assess the impact of changes in the risk factor distribution on absolute risk for an individual and at the population level. As an illustration we use an absolute risk prediction model for breast cancer that includes modifiable risk factors in addition to standard breast cancer risk factors. Influence function based variance estimates for absolute risk and the criteria are compared to bootstrap variance estimates.

Risk estimation and evaluation

Energy Technology Data Exchange (ETDEWEB)

Ferguson, R A.D.

1982-10-01

Risk assessment involves subjectivity, which makes objective decision making difficult in the nuclear power debate. The author reviews the process and uncertainties of estimating risks as well as the potential for misinterpretation and misuse. Risk data from a variety of aspects cannot be summed because the significance of different risks is not comparable. A method for including political, social, moral, psychological, and economic factors, environmental impacts, catastrophes, and benefits in the evaluation process could involve a broad base of lay and technical consultants, who would explain and argue their evaluation positions. 15 references. (DCK)

Impact of microbial count distributions on human health risk estimates

DEFF Research Database (Denmark)

Ribeiro Duarte, Ana Sofia; Nauta, Maarten

2015-01-01

Quantitative microbiological risk assessment (QMRA) is influenced by the choice of the probability distribution used to describe pathogen concentrations, as this may eventually have a large effect on the distribution of doses at exposure. When fitting a probability distribution to microbial...... enumeration data, several factors may have an impact on the accuracy of that fit. Analysis of the best statistical fits of different distributions alone does not provide a clear indication of the impact in terms of risk estimates. Thus, in this study we focus on the impact of fitting microbial distributions...... on risk estimates, at two different concentration scenarios and at a range of prevalence levels. By using five different parametric distributions, we investigate whether different characteristics of a good fit are crucial for an accurate risk estimate. Among the factors studied are the importance...

Risk Probability Estimating Based on Clustering

DEFF Research Database (Denmark)

Chen, Yong; Jensen, Christian D.; Gray, Elizabeth

2003-01-01

of prior experiences, recommendations from a trusted entity or the reputation of the other entity. In this paper we propose a dynamic mechanism for estimating the risk probability of a certain interaction in a given environment using hybrid neural networks. We argue that traditional risk assessment models...... from the insurance industry do not directly apply to ubiquitous computing environments. Instead, we propose a dynamic mechanism for risk assessment, which is based on pattern matching, classification and prediction procedures. This mechanism uses an estimator of risk probability, which is based...

Crossover effect of spouse weekly working hours on estimated 10-years risk of cardiovascular disease.

Directory of Open Access Journals (Sweden)

Mo-Yeol Kang

Full Text Available To investigate the association between spouse weekly working hours (SWWH and the estimated 10-years risk of cardiovascular disease (CVD.This cross-sectional study was based on the data obtained from the Korean National Health and Nutrition Examination Survey 2007-2012. Data of 16,917 participants (8,330 husbands, 8,587 wives were used for this analysis. The participants' clinical data were collected to estimate the 10-years risk of CVD, as well as weekly working hours. Multiple logistic regression was conducted to investigate the association between SWWH and the estimated 10-years risk of CVD. We also performed a stratified analysis according to each participant's and their spouse's employment status.Compared to those whose spouses worked 30 hours per week, estimated 10-years risk of CVD was significantly higher as SWWH increase among those whose spouses worked >30 hours per week. After adjusting for covariates, the odds ratio for high CVD risk was found to increase as SWWH increased, up to 2.52 among husbands and 2.43 among wives. We also found that the association between SWWH and the estimated 10-years risk of CVD varied according to the employment status. Analysis of each component included in the CVD appraisal model showed that SWWH had close relationship with diabetes in men, and smoking habits in women.Spouse's long working hours are associated with individual's risk of CVD in future, especially among husbands.

Cancer risk estimation from the A-bomb survivors

International Nuclear Information System (INIS)

Pierce, D.A.; Vaeth, M.

1989-10-01

Generalizations regarding radiogenic cancer risks from the A-bomb survivor data of the Radiation Effects Research Foundation involve a large number of well-identified uncertainties and approximations. These include extrapolation to low doses and dose rates, projections in time, sampling variation, the quality of the data, extrapolation to other populations, and the use of simplifying conventions. This paper discusses some of these issues, with emphasis on the first three. Results are given regarding the maximum 'linear-quadratic' curvature consistent with these data, taking into account uncertainties in individual exposure estimates. Discussion is given regarding use of relative risk models and projection of lifetime risks, emphasizing results for those who were old enough at exposure to have been followed up for a major part of their lives by now, and stressing the speculative aspects of conclusions about those exposed as children. Combining these results, and brief discussion of other uncertainties itemized above, comment is made on the evolution of risk estimates over the past 15 years. (author)

The Additive Risk Model for Estimation of Effect of Haplotype Match in BMT Studies

DEFF Research Database (Denmark)

Scheike, Thomas; Martinussen, T; Zhang, MJ

2011-01-01

leads to a missing data problem. We show how Aalen's additive risk model can be applied in this setting with the benefit that the time-varying haplomatch effect can be easily studied. This problem has not been considered before, and the standard approach where one would use the expected-maximization (EM......) algorithm cannot be applied for this model because the likelihood is hard to evaluate without additional assumptions. We suggest an approach based on multivariate estimating equations that are solved using a recursive structure. This approach leads to an estimator where the large sample properties can...... be developed using product-integration theory. Small sample properties are investigated using simulations in a setting that mimics the motivating haplomatch problem....

Risk estimates for meningiomas and other late effects after diagnostic X-ray exposure of the skull

International Nuclear Information System (INIS)

Pflugbeil, S.; Pflugbeil, C.; Schmitz-Feuerhake, I.

2011-01-01

This study aims to investigate the contribution of diagnostic exposures to the rising rates of brain tumours and other neoplasms which are observed in several industrial nations. Included are benign tumours in the head and neck region and cataracts which are neglected in usual risk estimates by international and national radiation protection committees. Dose-effect relationships for tumours of the brain, skin, thyroid and other sites of the head region, leukaemia and cataracts are taken from the literature. Risk estimates are derived for paediatric head computed tomographies (CTs) as well as for brain tumours in adults. On the basis of estimates for Germany about the number of head scans, the annual rate of radiation-induced diseases is calculated. About 1000 annual paediatric CT investigations of the skull will lead to about three excess neoplasms in the head region, i.e. the probability of an induced late effect must be suspected in the range of some thousands. Additionally, a relevant increase of cataracts must be considered. The radiation-induced occurrence of meningiomas and other brain tumours most probably contributes to the continuously increasing incidence of these diseases which is observed in several industrial nations, as well as the exposure of the bone marrow by CT to the increase of childhood leukaemia. (authors)

Minimax estimation of qubit states with Bures risk

Science.gov (United States)

Acharya, Anirudh; Guţă, Mădălin

2018-04-01

The central problem of quantum statistics is to devise measurement schemes for the estimation of an unknown state, given an ensemble of n independent identically prepared systems. For locally quadratic loss functions, the risk of standard procedures has the usual scaling of 1/n. However, it has been noticed that for fidelity based metrics such as the Bures distance, the risk of conventional (non-adaptive) qubit tomography schemes scales as 1/\\sqrt{n} for states close to the boundary of the Bloch sphere. Several proposed estimators appear to improve this scaling, and our goal is to analyse the problem from the perspective of the maximum risk over all states. We propose qubit estimation strategies based on separate adaptive measurements, and collective measurements, that achieve 1/n scalings for the maximum Bures risk. The estimator involving local measurements uses a fixed fraction of the available resource n to estimate the Bloch vector direction; the length of the Bloch vector is then estimated from the remaining copies by measuring in the estimator eigenbasis. The estimator based on collective measurements uses local asymptotic normality techniques which allows us to derive upper and lower bounds to its maximum Bures risk. We also discuss how to construct a minimax optimal estimator in this setup. Finally, we consider quantum relative entropy and show that the risk of the estimator based on collective measurements achieves a rate O(n-1log n) under this loss function. Furthermore, we show that no estimator can achieve faster rates, in particular the ‘standard’ rate n ‑1.

Simplifying cardiovascular risk estimation using resting heart rate.

LENUS (Irish Health Repository)

Cooney, Marie Therese

2010-09-01

Elevated resting heart rate (RHR) is a known, independent cardiovascular (CV) risk factor, but is not included in risk estimation systems, including Systematic COronary Risk Evaluation (SCORE). We aimed to derive risk estimation systems including RHR as an extra variable and assess the value of this addition.

The impact on radiation risk estimates of effect modifiers and confounders

International Nuclear Information System (INIS)

Sharp, G.B.; Cologne, J.B.; Pierce, D.A.; Tokuoka, S.

2003-01-01

We have conducted studies of the joint effects of radiation with other risk factors for liver, lung, and breast cancer in the cohort of Japanese survivors of the 1945 atomic bombings. Based on follow-up of 45,113 subjects from 1958 through 1994, of whom 592 developed lung cancer, we found the effects of smoking and radiation to be significantly non-multiplicative and consistent with additivity. Adjustment for smoking reduced the female:male ratio of radiation risk estimates for lung cancer in this cohort from 5.8 to 1.6, a ratio more similar to that for all solid cancers. We conducted cross sectional and case control studies within the A-bomb survivor cohort to assess the joint effects of radiation with hepatitis B virus (HBV) and C virus (HCV) infections on the etiology of liver cirrhosis and hepatocellular carcinoma (HCC). Our study of 268 pathologist-confirmed cirrhosis cases and 843 subjects without cirrhosis, found no relationship between A-bomb radiation and cirrhosis after adjustment for viral hepatitis. In terms of HCC, our study of 238 pathologist-confirmed cases and 894 controls showed super-multiplicative interaction between radiation and HCV infections. Our results suggest that while chronic radiation exposure acts as a complete carcinogen for HCC, acute irradiation may act in concert with an agent such as HCV that is associated with liver cell proliferation. Studies in progress of the joint effects of radiation with insulin-like growth factor 1 (IGF-1) and IGF Binding Protein 3 (IGFBP-3), and total estradiol on the etiology of breast cancer, a particularly radiogenic tumor, will also be discussed

Estimating cancer risks to adults undergoing body CT examinations

International Nuclear Information System (INIS)

Huda, W.; He, W.

2012-01-01

The purpose of the study is to estimate cancer risks from the amount of radiation used to perform body computed tomography (CT) examination. The ImPACT CT Patient Dosimetry Calculator was used to compute values of organ doses for adult body CT examinations. The radiation used to perform each examination was quantified by the dose-length product (DLP). Patient organ doses were converted into corresponding age and sex dependent cancer risks using data from BEIR VII. Results are presented for cancer risks per unit DLP and unit effective dose for 11 sensitive organs, as well as estimates of the contribution from 'other organs'. For patients who differ from a standard sized adult, correction factors based on the patient weight and antero-posterior dimension are provided to adjust organ doses and the corresponding risks. At constant incident radiation intensity, for CT examinations that include the chest, risks for females are markedly higher than those for males, whereas for examinations that include the pelvis, risks in males were slightly higher than those in females. In abdominal CT scans, risks for males and female patients are very similar. For abdominal CT scans, increasing the patient age from 20 to 80 resulted in a reduction in patient risks of nearly a factor of 5. The average cancer risk for chest/abdomen/pelvis CT examinations was ∼26 % higher than the cancer risk caused by 'sensitive organs'. Doses and radiation risks in 80 kg adults were ∼10 % lower than those in 70 kg patients. Cancer risks in body CT can be estimated from the examination DLP by accounting for sex, age, as well as patient physical characteristics. (authors)

Prevalence Estimates for Pharmacological Neuroenhancement in Austrian University Students: Its Relation to Health-Related Risk Attitude and the Framing Effect of Caffeine Tablets

Directory of Open Access Journals (Sweden)

Pavel Dietz

2018-06-01

Full Text Available Background: Pharmacological neuroenhancement (PN is defined as the use of illicit or prescription drugs by healthy individuals for cognitive-enhancing purposes. The present study aimed (i to investigate whether including caffeine tablets in the definition of PN within a questionnaire increases the PN prevalence estimate (framing effect, (ii to investigate whether the health-related risk attitude is increased in students who use PN.Materials and methods: Two versions of a paper-and-pencil questionnaire (first version included caffeine tablets in the definition of PN, the second excluded caffeine tablets were distributed among university students at the University of Graz, Austria. The unrelated question model (UQM was used to estimate the 12-month PN prevalence and the German version of the 30-item Domain-Specific Risk-Taking (DOSPERT scale to assess the health-related risk attitude. Moreover, large-sample z-tests (α = 0.05 were performed for comparing the PN prevalence estimates of two groups.Results: Two thousand four hundred and eighty-nine questionnaires were distributed and 2,284 (91.8% questionnaires were included in analysis. The overall PN prevalence estimate for all students was 11.9%. One-tailed large-sample z-tests revealed that the PN estimate for students with higher health-related risk attitude was significantly higher compared to students with lower health-related risk attitude (15.6 vs. 8.5%; z = 2.65, p = 0.004. Furthermore, when caffeine tablets were included into the example of PN, the prevalence estimate of PN was significantly higher compared to the version without caffeine tablets (14.9 vs. 9.0%; z = 2.20, p = 0.014.Discussion: This study revealed that the PN prevalence estimate increases when caffeine tablets are included in the definition of PN. Therefore, future studies investigating the prevalence of, and predictors for, PN should be performed and interpreted with respect to potential framing effects. This study further

Estimating the risk of cardio vascular diseases among pakistani diabetics using uk pds risk engine

International Nuclear Information System (INIS)

Moazzam, A.; Amer, J.

2015-01-01

The concept of risk estimation of Coronary Heart Disease (CHD) is helpful for clinician to identifying high risk populations for their effective treatment. Latest studies recommended only initiating cardio-protective treatment in diabetic patients based on personalized CHD risk estimates so as to reduce undue harm from overly aggressive risk factor modification. The United Kingdom Prospective Diabetes Study (UK PDS) Risk Engine is a widely used tool to assess the risk of Cardio Vascular diseases (CVD) in diabetics. The literature search so far did not reveal any study of risk assessment among Pakistani Diabetics. Methods: This descriptive study is based on the data of 470 type-2 diabetics seen in Department of Endocrinology and Metabolism, Services Institute of Medical Sciences, Lahore during 2011. The data of these 470 patients was analyzed through UKPDS Risk Engine. CHD risk was calculated. Results: The 10 years risk of CHD, fatal CHD, stroke and fatal stroke was 9.4%, 4.4%, 1.7% and 0.2% respectively. Conclusions: The present study show a lower risk of CVD occurring among Pakistani diabetics as compared to studies from western countries. (author)

How are flood risk estimates affected by the choice of return-periods?

Science.gov (United States)

Ward, P. J.; de Moel, H.; Aerts, J. C. J. H.

2011-12-01

Flood management is more and more adopting a risk based approach, whereby flood risk is the product of the probability and consequences of flooding. One of the most common approaches in flood risk assessment is to estimate the damage that would occur for floods of several exceedance probabilities (or return periods), to plot these on an exceedance probability-loss curve (risk curve) and to estimate risk as the area under the curve. However, there is little insight into how the selection of the return-periods (which ones and how many) used to calculate risk actually affects the final risk calculation. To gain such insights, we developed and validated an inundation model capable of rapidly simulating inundation extent and depth, and dynamically coupled this to an existing damage model. The method was applied to a section of the River Meuse in the southeast of the Netherlands. Firstly, we estimated risk based on a risk curve using yearly return periods from 2 to 10 000 yr (€ 34 million p.a.). We found that the overall risk is greatly affected by the number of return periods used to construct the risk curve, with over-estimations of annual risk between 33% and 100% when only three return periods are used. In addition, binary assumptions on dike failure can have a large effect (a factor two difference) on risk estimates. Also, the minimum and maximum return period considered in the curve affects the risk estimate considerably. The results suggest that more research is needed to develop relatively simple inundation models that can be used to produce large numbers of inundation maps, complementary to more complex 2-D-3-D hydrodynamic models. It also suggests that research into flood risk could benefit by paying more attention to the damage caused by relatively high probability floods.

Estimating 'Value at Risk' of crude oil price and its spillover effect using the GED-GARCH approach

International Nuclear Information System (INIS)

Fan, Ying; Wei, Yi-Ming; Zhang, Yue-Jun; Tsai, Hsien-Tang

2008-01-01

Estimation has been carried out using GARCH-type models, based on the Generalized Error Distribution (GED), for both the extreme downside and upside Value-at-Risks (VaR) of returns in the WTI and Brent crude oil spot markets. Furthermore, according to a new concept of Granger causality in risk, a kernel-based test is proposed to detect extreme risk spillover effect between the two oil markets. Results of an empirical study indicate that the GED-GARCH-based VaR approach appears more effective than the well-recognized HSAF (i.e. historical simulation with ARMA forecasts). Moreover, this approach is also more realistic and comprehensive than the standard normal distribution-based VaR model that is commonly used. Results reveal that there is significant two-way risk spillover effect between WTI and Brent markets. Supplementary study indicates that at the 99% confidence level, when negative market news arises that brings about a slump in oil price return, historical information on risk in the WTI market helps to forecast the Brent market. Conversely, it is not the case when positive news occurs and returns rise. Historical information on risk in the two markets can facilitate forecasts of future extreme market risks for each other. These results are valuable for anyone who needs evaluation and forecasts of the risk situation in international crude oil markets. (author)

Risk estimates for exposure to alpha emitters

International Nuclear Information System (INIS)

1982-07-01

The primary scope of this report is to evaluate the risk of lung cancer from occupational exposure to short-lived daughters of radon and thoron. The Subcommittee on Risk Estimates considers that inhalation of radon and thoron daughters is the major radiation hazard from alpha radiation in uranium mining. The secondary scope of this report is the consideration of the applicability of the risk estimates derived from miners to the general public. The risk to members of the public from radium-226 in drinking water is also considered. Some research requirments are suggested

The estimated effect of mass or footprint reduction in recent light-duty vehicles on U.S. societal fatality risk per vehicle mile traveled.

Science.gov (United States)

Wenzel, Tom

2013-10-01

The National Highway Traffic Safety Administration (NHTSA) recently updated its 2003 and 2010 logistic regression analyses of the effect of a reduction in light-duty vehicle mass on US societal fatality risk per vehicle mile traveled (VMT; Kahane, 2012). Societal fatality risk includes the risk to both the occupants of the case vehicle as well as any crash partner or pedestrians. The current analysis is the most thorough investigation of this issue to date. This paper replicates the Kahane analysis and extends it by testing the sensitivity of his results to changes in the definition of risk, and the data and control variables used in the regression models. An assessment by Lawrence Berkeley National Laboratory (LBNL) indicates that the estimated effect of mass reduction on risk is smaller than in Kahane's previous studies, and is statistically non-significant for all but the lightest cars (Wenzel, 2012a). The estimated effects of a reduction in mass or footprint (i.e. wheelbase times track width) are small relative to other vehicle, driver, and crash variables used in the regression models. The recent historical correlation between mass and footprint is not so large to prohibit including both variables in the same regression model; excluding footprint from the model, i.e. allowing footprint to decrease with mass, increases the estimated detrimental effect of mass reduction on risk in cars and crossover utility vehicles (CUVs)/minivans, but has virtually no effect on light trucks. Analysis by footprint deciles indicates that risk does not consistently increase with reduced mass for vehicles of similar footprint. Finally, the estimated effects of mass and footprint reduction are sensitive to the measure of exposure used (fatalities per induced exposure crash, rather than per VMT), as well as other changes in the data or control variables used. It appears that the safety penalty from lower mass can be mitigated with careful vehicle design, and that manufacturers can

Review of the current status of radiation risk estimates

International Nuclear Information System (INIS)

Charles, M.W.; Little, M.P.

1988-10-01

This report reviews the current status of radiation risk estimation for low linear energy transfer radiation. Recent statements by various national and international organisations regarding risk estimates are critically discussed. The recently published revised population risk estimates from the study of Japanese bomb survivors are also reviewed and used with some unpublished data from Japan to calculate risk figures for a general work force. (author)

Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation

International Nuclear Information System (INIS)

Buhl, T.E.; Hansen, W.R.

1984-05-01

Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables

Estimating the risks of cancer mortality and genetic defects resulting from exposures to low levels of ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Buhl, T.E.; Hansen, W.R.

1984-05-01

Estimators for calculating the risk of cancer and genetic disorders induced by exposure to ionizing radiation have been recommended by the US National Academy of Sciences Committee on the Biological Effects of Ionizing Radiations, the UN Scientific Committee on the Effects of Atomic Radiation, and the International Committee on Radiological Protection. These groups have also considered the risks of somatic effects other than cancer. The US National Council on Radiation Protection and Measurements has discussed risk estimate procedures for radiation-induced health effects. The recommendations of these national and international advisory committees are summarized and compared in this report. Based on this review, two procedures for risk estimation are presented for use in radiological assessments performed by the US Department of Energy under the National Environmental Policy Act of 1969 (NEPA). In the first procedure, age- and sex-averaged risk estimators calculated with US average demographic statistics would be used with estimates of radiation dose to calculate the projected risk of cancer and genetic disorders that would result from the operation being reviewed under NEPA. If more site-specific risk estimators are needed, and the demographic information is available, a second procedure is described that would involve direct calculation of the risk estimators using recommended risk-rate factors. The computer program REPCAL has been written to perform this calculation and is described in this report. 25 references, 16 tables.

The effects of spatial population dataset choice on estimates of population at risk of disease

Directory of Open Access Journals (Sweden)

Gething Peter W

2011-02-01

Full Text Available Abstract Background The spatial modeling of infectious disease distributions and dynamics is increasingly being undertaken for health services planning and disease control monitoring, implementation, and evaluation. Where risks are heterogeneous in space or dependent on person-to-person transmission, spatial data on human population distributions are required to estimate infectious disease risks, burdens, and dynamics. Several different modeled human population distribution datasets are available and widely used, but the disparities among them and the implications for enumerating disease burdens and populations at risk have not been considered systematically. Here, we quantify some of these effects using global estimates of populations at risk (PAR of P. falciparum malaria as an example. Methods The recent construction of a global map of P. falciparum malaria endemicity enabled the testing of different gridded population datasets for providing estimates of PAR by endemicity class. The estimated population numbers within each class were calculated for each country using four different global gridded human population datasets: GRUMP (~1 km spatial resolution, LandScan (~1 km, UNEP Global Population Databases (~5 km, and GPW3 (~5 km. More detailed assessments of PAR variation and accuracy were conducted for three African countries where census data were available at a higher administrative-unit level than used by any of the four gridded population datasets. Results The estimates of PAR based on the datasets varied by more than 10 million people for some countries, even accounting for the fact that estimates of population totals made by different agencies are used to correct national totals in these datasets and can vary by more than 5% for many low-income countries. In many cases, these variations in PAR estimates comprised more than 10% of the total national population. The detailed country-level assessments suggested that none of the datasets was

Explaining behavior change after genetic testing: the problem of collinearity between test results and risk estimates.

Science.gov (United States)

Fanshawe, Thomas R; Prevost, A Toby; Roberts, J Scott; Green, Robert C; Armstrong, David; Marteau, Theresa M

2008-09-01

This paper explores whether and how the behavioral impact of genotype disclosure can be disentangled from the impact of numerical risk estimates generated by genetic tests. Secondary data analyses are presented from a randomized controlled trial of 162 first-degree relatives of Alzheimer's disease (AD) patients. Each participant received a lifetime risk estimate of AD. Control group estimates were based on age, gender, family history, and assumed epsilon4-negative apolipoprotein E (APOE) genotype; intervention group estimates were based upon the first three variables plus true APOE genotype, which was also disclosed. AD-specific self-reported behavior change (diet, exercise, and medication use) was assessed at 12 months. Behavior change was significantly more likely with increasing risk estimates, and also more likely, but not significantly so, in epsilon4-positive intervention group participants (53% changed behavior) than in control group participants (31%). Intervention group participants receiving epsilon4-negative genotype feedback (24% changed behavior) and control group participants had similar rates of behavior change and risk estimates, the latter allowing assessment of the independent effects of genotype disclosure. However, collinearity between risk estimates and epsilon4-positive genotypes, which engender high-risk estimates, prevented assessment of the independent effect of the disclosure of an epsilon4 genotype. Novel study designs are proposed to determine whether genotype disclosure has an impact upon behavior beyond that of numerical risk estimates.

Impact of risk factors on cardiovascular risk: a perspective on risk estimation in a Swiss population.

Science.gov (United States)

Chrubasik, Sigrun A; Chrubasik, Cosima A; Piper, Jörg; Schulte-Moenting, Juergen; Erne, Paul

2015-01-01

In models and scores for estimating cardiovascular risk (CVR), the relative weightings given to blood pressure measurements (BPMs), and biometric and laboratory variables are such that even large differences in blood pressure lead to rather low differences in the resulting total risk when compared with other concurrent risk factors. We evaluated this phenomenon based on the PROCAM score, using BPMs made by volunteer subjects at home (HBPMs) and automated ambulatory BPMs (ABPMs) carried out in the same subjects. A total of 153 volunteers provided the data needed to estimate their CVR by means of the PROCAM formula. Differences (deltaCVR) between the risk estimated by entering the ABPM and that estimated with the HBPM were compared with the differences (deltaBPM) between the ABPM and the corresponding HBPM. In addition to the median values (= second quartile), the first and third quartiles of blood pressure profiles were also considered. PROCAM risk values were converted to European Society of Cardiology (ESC) risk values and all participants were assigned to the risk groups low, medium and high. Based on the PROCAM score, 132 participants had a low risk for suffering myocardial infarction, 16 a medium risk and 5 a high risk. The calculated ESC scores classified 125 participants into the low-risk group, 26 into the medium- and 2 into the high-risk group for death from a cardiovascular event. Mean ABPM tended to be higher than mean HBPM. Use of mean systolic ABPM or HBPM in the PROCAM formula had no major impact on the risk level. Our observations are in agreement with the rather low weighting of blood pressure as risk determinant in the PROCAM score. BPMs assessed with different methods had relatively little impact on estimation of cardiovascular risk in the given context of other important determinants. The risk calculations in our unselected population reflect the given classification of Switzerland as a so-called cardiovascular "low risk country".

The Boehringer Ingelheim employee study (Part 2): 10-year cardiovascular diseases risk estimation.

Science.gov (United States)

Kempf, K; Martin, S; Döhring, C; Dugi, K; Haastert, B; Schneider, M

2016-10-01

Cardiovascular disease (CVD) may cause an economic burden to companies, but CVD risk estimations specific to working populations are lacking. To estimate the 10-year CVD risk in the Boehringer Ingelheim (BI) employee cohort and analyse the potential effect of hypothetical risk reduction interventions. We estimated CVD risk using the Framingham (FRS), PROCAM (PRS) and Reynolds (RRS) risk scores, using cross-sectional baseline data on BI Pharma employees collected from 2005 to 2011. Results were compared using Fisher's exact and Wilcoxon tests. The predictive ability of the score estimates was assessed using receiver-operating characteristics analyses. Among the 4005 study subjects, we estimated 10-year CVD risks of 35% (FRS), 9% (PRS) and 6% (RRS) for men and 10% (FRS), 4% (PRS) and 1% (RRS) for women. One hundred and thirty-four (6%) men and 111 (6%) women employees had current CVD. The best predictors of prevalent CVD were the FRS and the RRS for men [area-under-the-curve 0.62 (0.57-0.67) for both]. A hypothetical intervention that would improve systolic blood pressure, HbA1c (for diabetes), C-reactive protein, triglycerides and total and high-density lipoprotein cholesterol by 10% each would potentially reduce expected CVD cases by 36-41% in men and 30-45% in women, and if smoking cessation is incorporated, by 39-45% and 30-55%, respectively, depending on the pre-intervention risk score. There was a substantial risk of developing CVD in this working cohort. Occupational health programmes with lifestyle interventions for high-risk individuals may be an effective risk reduction measure. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Multivariate Risk-Return Decision Making Within Dynamic Estimation

Directory of Open Access Journals (Sweden)

Josip Arnerić

2008-10-01

Full Text Available Risk management in this paper is focused on multivariate risk-return decision making assuming time-varying estimation. Empirical research in risk management showed that the static "mean-variance" methodology in portfolio optimization is very restrictive with unrealistic assumptions. The objective of this paper is estimation of time-varying portfolio stocks weights by constraints on risk measure. Hence, risk measure dynamic estimation is used in risk controlling. By risk control manager makes free supplementary capital for new investments.Univariate modeling approach is not appropriate, even when portfolio returns are treated as one variable. Portfolio weights are time-varying, and therefore it is necessary to reestimate whole model over time. Using assumption of bivariate Student´s t-distribution, in multivariate GARCH(p,q models, it becomes possible to forecast time-varying portfolio risk much more precisely. The complete procedure of analysis is established from Zagreb Stock Exchange using daily observations of Pliva and Podravka stocks.

An application of extreme value theory in estimating liquidity risk

Directory of Open Access Journals (Sweden)

Sonia Benito Muela

2017-09-01

Full Text Available The last global financial crisis (2007–2008 has highlighted the weaknesses of value at risk (VaR as a measure of market risk, as this metric by itself does not take liquidity risk into account. To address this problem, the academic literature has proposed incorporating liquidity risk into estimations of market risk by adding the VaR of the spread to the risk price. The parametric model is the standard approach used to estimate liquidity risk. As this approach does not generate reliable VaR estimates, we propose estimating liquidity risk using more sophisticated models based on extreme value theory (EVT. We find that the approach based on conditional extreme value theory outperforms the standard approach in terms of accurate VaR estimates and the market risk capital requirements of the Basel Capital Accord.

Estimation of radiation cancer risk in CT-KUB

Science.gov (United States)

Karim, M. K. A.; Hashim, S.; Bakar, K. A.; Bradley, D. A.; Ang, W. C.; Bahrudin, N. A.; Mhareb, M. H. A.

2017-08-01

The increased demand for computed tomography (CT) in radiological scanning examinations raises the question of a potential health impact from the associated radiation exposures. Focusing on CT kidney-ureter-bladder (CT-KUB) procedures, this work was aimed at determining organ equivalent dose using a commercial CT dose calculator and providing an estimate of cancer risks. The study, which included 64 patients (32 males and 32 females, mean age 55.5 years and age range 30-80 years), involved use of a calibrated CT scanner (Siemens-Somatom Emotion 16-slice). The CT exposures parameter including tube potential, pitch factor, tube current, volume CT dose index (CTDIvol) and dose-length product (DLP) were recorded and analyzed using CT-EXPO (Version 2.3.1, Germany). Patient organ doses, including for stomach, liver, colon, bladder, red bone marrow, prostate and ovaries were calculated and converted into cancer risks using age- and sex-specific data published in the Biological Effects of Ionizing Radiation (BEIR) VII report. With a median value scan range of 36.1 cm, the CTDIvol, DLP, and effective dose were found to be 10.7 mGy, 390.3 mGy cm and 6.2 mSv, respectively. The mean cancer risks for males and females were estimated to be respectively 25 and 46 out of 100,000 procedures with effective doses between 4.2 mSv and 10.1 mSv. Given the increased cancer risks from current CT-KUB procedures compared to conventional examinations, we propose that the low dose protocols for unenhanced CT procedures be taken into consideration before establishing imaging protocols for CT-KUB.

Graphs to estimate an individualized risk of breast cancer.

Science.gov (United States)

Benichou, J; Gail, M H; Mulvihill, J J

1996-01-01

Clinicians who counsel women about their risk for developing breast cancer need a rapid method to estimate individualized risk (absolute risk), as well as the confidence limits around that point. The Breast Cancer Detection Demonstration Project (BCDDP) model (sometimes called the Gail model) assumes no genetic model and simultaneously incorporates five risk factors, but involves cumbersome calculations and interpolations. This report provides graphs to estimate the absolute risk of breast cancer from the BCDDP model. The BCDDP recruited 280,000 women from 1973 to 1980 who were monitored for 5 years. From this cohort, 2,852 white women developed breast cancer and 3,146 controls were selected, all with complete risk-factor information. The BCDDP model, previously developed from these data, was used to prepare graphs that relate a specific summary relative-risk estimate to the absolute risk of developing breast cancer over intervals of 10, 20, and 30 years. Once a summary relative risk is calculated, the appropriate graph is chosen that shows the 10-, 20-, or 30-year absolute risk of developing breast cancer. A separate graph gives the 95% confidence limits around the point estimate of absolute risk. Once a clinician rules out a single gene trait that predisposes to breast cancer and elicits information on age and four risk factors, the tables and figures permit an estimation of a women's absolute risk of developing breast cancer in the next three decades. These results are intended to be applied to women who undergo regular screening. They should be used only in a formal counseling program to maximize a woman's understanding of the estimates and the proper use of them.

Methodology to estimate the cost of the severe accidents risk / maximum benefit

International Nuclear Information System (INIS)

Mendoza, G.; Flores, R. M.; Vega, E.

2016-09-01

For programs and activities to manage aging effects, any changes to plant operations, inspections, maintenance activities, systems and administrative control procedures during the renewal period should be characterized, designed to manage the effects of aging as required by 10 Cfr Part 54 that could impact the environment. Environmental impacts significantly different from those described in the final environmental statement for the current operating license should be described in detail. When complying with the requirements of a license renewal application, the Severe Accident Mitigation Alternatives (SAMA) analysis is contained in a supplement to the environmental report of the plant that meets the requirements of 10 Cfr Part 51. In this paper, the methodology for estimating the cost of severe accidents risk is established and discussed, which is then used to identify and select the alternatives for severe accident mitigation, which are analyzed to estimate the maximum benefit that an alternative could achieve if this eliminate all risk. Using the regulatory analysis techniques of the US Nuclear Regulatory Commission (NRC) estimates the cost of severe accidents risk. The ultimate goal of implementing the methodology is to identify candidates for SAMA that have the potential to reduce the severe accidents risk and determine if the implementation of each candidate is cost-effective. (Author)

Radiation risk estimation based on measurement error models

CERN Document Server

Masiuk, Sergii; Shklyar, Sergiy; Chepurny, Mykola; Likhtarov, Illya

2017-01-01

This monograph discusses statistics and risk estimates applied to radiation damage under the presence of measurement errors. The first part covers nonlinear measurement error models, with a particular emphasis on efficiency of regression parameter estimators. In the second part, risk estimation in models with measurement errors is considered. Efficiency of the methods presented is verified using data from radio-epidemiological studies.

A novel tool for user-friendly estimation of natural, diagnostic and professional radiation risk: Radio-Risk software

International Nuclear Information System (INIS)

Carpeggiani, Clara; Paterni, Marco; Caramella, Davide; Vano, Eliseo; Semelka, Richard C.; Picano, Eugenio

2012-01-01

Background: Awareness of radiological risk is low among doctors and patients. An educational/decision tool that considers each patient’ s cumulative lifetime radiation exposure would facilitate provider–patient communication. Aim: The purpose of this work was to develop user-friendly software for simple estimation and communication of radiological risk to patients and doctors as a part of the SUIT-Heart (Stop Useless Imaging Testing in Heart disease) Project of the Tuscany Region. Methods: We developed a novel software program (PC-platform, Windows OS fully downloadable at (http://suit-heart.ifc.cnr.it)) considering reference dose estimates from American Heart Association Radiological Imaging 2009 guidelines and UK Royal College of Radiology 2007 guidelines. Cancer age and gender-weighted risk were derived from Biological Effects of Ionising Radiation VII Committee, 2006. Results: With simple input functions (demographics, age, gender) the user selects from a predetermined menu variables relating to natural (e.g., airplane flights and geo-tracked background exposure), professional (e.g., cath lab workers) and medical (e.g., CT, cardiac scintigraphy, coronary stenting) sources. The program provides a simple numeric (cumulative effective dose in milliSievert, mSv, and equivalent number of chest X-rays) and graphic (cumulative temporal trends of exposure, cancer cases out of 100 exposed persons) display. Conclusions: A simple software program allows straightforward estimation of cumulative dose (in multiples of chest X-rays) and risk (in extra % lifetime cancer risk), with simple numbers quantifying lifetime extra cancer risk. Pictorial display of radiation risk may be valuable for increasing radiological awareness in cardiologists.

A novel tool for user-friendly estimation of natural, diagnostic and professional radiation risk: Radio-Risk software

Energy Technology Data Exchange (ETDEWEB)

Carpeggiani, Clara; Paterni, Marco [CNR, Institute of Clinical Physiology (Italy); Caramella, Davide [Radiology Department, Pisa University, Pisa (Italy); Vano, Eliseo [San Carlos Hospital, Radiology Department, Complutense University, Madrid (Spain); Semelka, Richard C. [University of North Carolina, Chapel Hill, NC (United States); Picano, Eugenio, E-mail: picano@ifc.cnr.it [CNR, Institute of Clinical Physiology (Italy)

2012-11-15

Background: Awareness of radiological risk is low among doctors and patients. An educational/decision tool that considers each patient' s cumulative lifetime radiation exposure would facilitate provider-patient communication. Aim: The purpose of this work was to develop user-friendly software for simple estimation and communication of radiological risk to patients and doctors as a part of the SUIT-Heart (Stop Useless Imaging Testing in Heart disease) Project of the Tuscany Region. Methods: We developed a novel software program (PC-platform, Windows OS fully downloadable at (http://suit-heart.ifc.cnr.it)) considering reference dose estimates from American Heart Association Radiological Imaging 2009 guidelines and UK Royal College of Radiology 2007 guidelines. Cancer age and gender-weighted risk were derived from Biological Effects of Ionising Radiation VII Committee, 2006. Results: With simple input functions (demographics, age, gender) the user selects from a predetermined menu variables relating to natural (e.g., airplane flights and geo-tracked background exposure), professional (e.g., cath lab workers) and medical (e.g., CT, cardiac scintigraphy, coronary stenting) sources. The program provides a simple numeric (cumulative effective dose in milliSievert, mSv, and equivalent number of chest X-rays) and graphic (cumulative temporal trends of exposure, cancer cases out of 100 exposed persons) display. Conclusions: A simple software program allows straightforward estimation of cumulative dose (in multiples of chest X-rays) and risk (in extra % lifetime cancer risk), with simple numbers quantifying lifetime extra cancer risk. Pictorial display of radiation risk may be valuable for increasing radiological awareness in cardiologists.

Estimating the commodity market price of risk for energy prices

International Nuclear Information System (INIS)

Kolos, Sergey P.; Ronn, Ehud I.

2008-01-01

The purpose of this paper is to estimate the ''market price of risk'' (MPR) for energy commodities, the ratio of expected return to standard deviation. The MPR sign determines whether energy forward prices are upward- or downward-biased predictors of expected spot prices. We estimate MPRs using spot and futures prices, while accounting for the Samuelson effect. We find long-term MPRs generally positive and short-term negative, consistent with positive energy betas and hedging, respectively. In spot electricity markets, MPRs in Day-Ahead Prices agree with short-dated futures. Our results relate risk premia to informed hedging decisions, and futures prices to forecast/expected prices. (author)

Collective effective dose equivalent, population doses and risk estimates from occupational exposures in Japan

International Nuclear Information System (INIS)

Maruyama, Takashi; Nishizawa, Kanae; Kumamoto, Yoshikazu; Iwai, Kazuo; Mase, Naomichi.

1993-01-01

Collective dose equivalent and population dose from occupational exposures in Japan, 1988 were estimated on the basis of a nationwide survey. The survey was conducted on annual collective dose equivalents by sex, age group and type of radiation work for about 0.21 million workers except for the workers in nuclear power stations. The data on the workers in nuclear power stations were obtained from the official report of the Japan Nuclear Safety Commission. The total number of workers including nuclear power stations was estimated to be about 0.26 million. Radiation works were subdivided as follows: medical works including dental; non-atomic energy industry; research and education; atomic energy industry and nuclear power station. For the determination of effective dose equivalent and population dose, organ or tissue doses were measured with a phantom experiment. The resultant doses were compared with the doses previously calculated using a chord length technique and with data from ICRP publications. The annual collective effective dose equivalent were estimated to be about 21.94 person·Sv for medical workers, 7.73 person·Sv for industrial workers, 0.75 person·Sv for research and educational workers, 2.48 person·Sv for atomic energy industry and 84.4 person ·Sv for workers in nuclear power station. The population doses were calculated to be about 1.07 Sv for genetically significant dose, 0.89 Sv for leukemia significant dose and 0.42 Sv for malignant significant dose. The population risks were estimated using these population doses. (author)

Cardiovascular risk estimation in older persons

DEFF Research Database (Denmark)

Cooney, Marie Therese; Selmer, Randi; Lindman, Anja

2016-01-01

.73 to 0.75). Calibration was also reasonable, Hosmer-Lemeshow goodness of fit test: 17.16 (men), 22.70 (women). Compared with the original SCORE function extrapolated to the ≥65 years age group discrimination improved, p = 0.05 (men), p women). Simple risk charts were constructed. On simulated...... risk estimation systems, that risk factors function similarly in all age groups. We aimed to derive and validate a risk estimation function, SCORE O.P., solely from data from individuals aged 65 years and older. METHODS AND RESULTS: 20,704 men and 20,121 women, aged 65 and over and without pre...... model and were included in the SCORE O.P. model were: age, total cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, smoking status and diabetes. SCORE O.P. showed good discrimination; area under receiver operator characteristic curve (AUROC) 0.74 (95% confidence interval: 0...

Estimating the Effectiveness of Health-Risk Communications with Propensity-Score Matching: Application to Arsenic Groundwater Contamination in Four US Locations

Directory of Open Access Journals (Sweden)

Andrew J. Leidner

2014-01-01

Full Text Available This paper provides a demonstration of propensity-score matching estimation methods to evaluate the effectiveness of health-risk communication efforts. This study develops a two-stage regression model to investigate household and respondent characteristics as they contribute to aversion behavior to reduce exposure to arsenic-contaminated groundwater. The aversion activity under study is a household-level point-of-use filtration device. Since the acquisition of arsenic contamination information and the engagement in an aversion activity may be codetermined, a two-stage propensity-score model is developed. In the first stage, the propensity for households to acquire arsenic contamination information is estimated. Then, the propensity scores are used to weight observations in a probit regression on the decision to avert the arsenic-related health risk. Of four potential sources of information, utility, media, friend, or others, information received from a friend appears to be the source of information most associated with aversion behavior. Other statistically significant covariates in the household’s decision to avert contamination include reported household income, the presence of children in household, and region-level indicator variables. These findings are primarily illustrative and demonstrate the usefulness of propensity-score methods to estimate health-risk communication effectiveness. They may also be suggestive of areas for future research.

Estimating the Effectiveness of Health-Risk Communications with Propensity-Score Matching: Application to Arsenic Groundwater Contamination in Four US Locations

Science.gov (United States)

Leidner, Andrew J.

2014-01-01

This paper provides a demonstration of propensity-score matching estimation methods to evaluate the effectiveness of health-risk communication efforts. This study develops a two-stage regression model to investigate household and respondent characteristics as they contribute to aversion behavior to reduce exposure to arsenic-contaminated groundwater. The aversion activity under study is a household-level point-of-use filtration device. Since the acquisition of arsenic contamination information and the engagement in an aversion activity may be codetermined, a two-stage propensity-score model is developed. In the first stage, the propensity for households to acquire arsenic contamination information is estimated. Then, the propensity scores are used to weight observations in a probit regression on the decision to avert the arsenic-related health risk. Of four potential sources of information, utility, media, friend, or others, information received from a friend appears to be the source of information most associated with aversion behavior. Other statistically significant covariates in the household's decision to avert contamination include reported household income, the presence of children in household, and region-level indicator variables. These findings are primarily illustrative and demonstrate the usefulness of propensity-score methods to estimate health-risk communication effectiveness. They may also be suggestive of areas for future research. PMID:25349622

Peer effects in risk aversion.

Science.gov (United States)

Balsa, Ana I; Gandelman, Néstor; González, Nicolás

2015-01-01

We estimate peer effects in risk attitudes in a sample of high school students. Relative risk aversion is elicited from surveys administered at school. Identification of peer effects is based on parents not being able to choose the class within the school of their choice, and on the use of instrumental variables conditional on school-grade fixed effects. We find a significant and quantitatively large impact of peers' risk attitudes on a male individual's coefficient of risk aversion. Specifically, a one standard deviation increase in the group's coefficient of risk aversion increases an individual's risk aversion by 43%. Our findings shed light on the origin and stability of risk attitudes and, more generally, on the determinants of economic preferences. © 2014 Society for Risk Analysis.

Methods for risk estimation in nuclear energy

Energy Technology Data Exchange (ETDEWEB)

Gauvenet, A [CEA, 75 - Paris (France)

1979-01-01

The author presents methods for estimating the different risks related to nuclear energy: immediate or delayed risks, individual or collective risks, risks of accidents and long-term risks. These methods have attained a highly valid level of elaboration and their application to other industrial or human problems is currently under way, especially in English-speaking countries.

Parametric estimation of P(X > Y) for normal distributions in the context of probabilistic environmental risk assessment.

Science.gov (United States)

Jacobs, Rianne; Bekker, Andriëtte A; van der Voet, Hilko; Ter Braak, Cajo J F

2015-01-01

Estimating the risk, P(X > Y), in probabilistic environmental risk assessment of nanoparticles is a problem when confronted by potentially small risks and small sample sizes of the exposure concentration X and/or the effect concentration Y. This is illustrated in the motivating case study of aquatic risk assessment of nano-Ag. A non-parametric estimator based on data alone is not sufficient as it is limited by sample size. In this paper, we investigate the maximum gain possible when making strong parametric assumptions as opposed to making no parametric assumptions at all. We compare maximum likelihood and Bayesian estimators with the non-parametric estimator and study the influence of sample size and risk on the (interval) estimators via simulation. We found that the parametric estimators enable us to estimate and bound the risk for smaller sample sizes and small risks. Also, the Bayesian estimator outperforms the maximum likelihood estimators in terms of coverage and interval lengths and is, therefore, preferred in our motivating case study.

Population-based absolute risk estimation with survey data

Science.gov (United States)

Kovalchik, Stephanie A.; Pfeiffer, Ruth M.

2013-01-01

Absolute risk is the probability that a cause-specific event occurs in a given time interval in the presence of competing events. We present methods to estimate population-based absolute risk from a complex survey cohort that can accommodate multiple exposure-specific competing risks. The hazard function for each event type consists of an individualized relative risk multiplied by a baseline hazard function, which is modeled nonparametrically or parametrically with a piecewise exponential model. An influence method is used to derive a Taylor-linearized variance estimate for the absolute risk estimates. We introduce novel measures of the cause-specific influences that can guide modeling choices for the competing event components of the model. To illustrate our methodology, we build and validate cause-specific absolute risk models for cardiovascular and cancer deaths using data from the National Health and Nutrition Examination Survey. Our applications demonstrate the usefulness of survey-based risk prediction models for predicting health outcomes and quantifying the potential impact of disease prevention programs at the population level. PMID:23686614

Estimating radiation risk induced by CT screening for Korean population

Science.gov (United States)

Yang, Won Seok; Yang, Hye Jeong; Min, Byung In

2017-02-01

The purposes of this study are to estimate the radiation risks induced by chest/abdomen computed tomography (CT) screening for healthcare and to determine the cancer risk level of the Korean population compared to other populations. We used an ImPACT CT Patient Dosimetry Calculator to compute the organ effective dose induced by CT screening (chest, low-dose chest, abdomen/pelvis, and chest/abdomen/pelvis CT). A risk model was applied using principles based on the BEIR VII Report in order to estimate the lifetime attributable risk (LAR) using the Korean Life Table 2010. In addition, several countries including Hong Kong, the United States (U.S.), and the United Kingdom, were selected for comparison. Herein, each population exposed radiation dose of 100 mSv was classified according to country, gender and age. For each CT screening the total organ effective dose calculated by ImPACT was 6.2, 1.5, 5.2 and 11.4 mSv, respectively. In the case of Korean female LAR, it was similar to Hong Kong female but lower than those of U.S. and U.K. females, except for those in their twenties. The LAR of Korean males was the highest for all types of CT screening. However, the difference of the risk level was negligible because of the quite low value.

Estimating the risk of Amazonian forest dieback.

Science.gov (United States)

Rammig, Anja; Jupp, Tim; Thonicke, Kirsten; Tietjen, Britta; Heinke, Jens; Ostberg, Sebastian; Lucht, Wolfgang; Cramer, Wolfgang; Cox, Peter

2010-08-01

*Climate change will very likely affect most forests in Amazonia during the course of the 21st century, but the direction and intensity of the change are uncertain, in part because of differences in rainfall projections. In order to constrain this uncertainty, we estimate the probability for biomass change in Amazonia on the basis of rainfall projections that are weighted by climate model performance for current conditions. *We estimate the risk of forest dieback by using weighted rainfall projections from 24 general circulation models (GCMs) to create probability density functions (PDFs) for future forest biomass changes simulated by a dynamic vegetation model (LPJmL). *Our probabilistic assessment of biomass change suggests a likely shift towards increasing biomass compared with nonweighted results. Biomass estimates range between a gain of 6.2 and a loss of 2.7 kg carbon m(-2) for the Amazon region, depending on the strength of CO(2) fertilization. *The uncertainty associated with the long-term effect of CO(2) is much larger than that associated with precipitation change. This underlines the importance of reducing uncertainties in the direct effects of CO(2) on tropical ecosystems.

Security Events and Vulnerability Data for Cybersecurity Risk Estimation.

Science.gov (United States)

Allodi, Luca; Massacci, Fabio

2017-08-01

Current industry standards for estimating cybersecurity risk are based on qualitative risk matrices as opposed to quantitative risk estimates. In contrast, risk assessment in most other industry sectors aims at deriving quantitative risk estimations (e.g., Basel II in Finance). This article presents a model and methodology to leverage on the large amount of data available from the IT infrastructure of an organization's security operation center to quantitatively estimate the probability of attack. Our methodology specifically addresses untargeted attacks delivered by automatic tools that make up the vast majority of attacks in the wild against users and organizations. We consider two-stage attacks whereby the attacker first breaches an Internet-facing system, and then escalates the attack to internal systems by exploiting local vulnerabilities in the target. Our methodology factors in the power of the attacker as the number of "weaponized" vulnerabilities he/she can exploit, and can be adjusted to match the risk appetite of the organization. We illustrate our methodology by using data from a large financial institution, and discuss the significant mismatch between traditional qualitative risk assessments and our quantitative approach. © 2017 Society for Risk Analysis.

Backtesting Portfolio Value-at-Risk with Estimated Portfolio Weights

OpenAIRE

Pei Pei

2010-01-01

This paper theoretically and empirically analyzes backtesting portfolio VaR with estimation risk in an intrinsically multivariate framework. For the first time in the literature, it takes into account the estimation of portfolio weights in forecasting portfolio VaR and its impact on backtesting. It shows that the estimation risk from estimating the portfolio weights as well as that from estimating the multivariate dynamic model of asset returns make the existing methods in a univariate framew...

Estimating Risk Parameters

OpenAIRE

Aswath Damodaran

1999-01-01

Over the last three decades, the capital asset pricing model has occupied a central and often controversial place in most corporate finance analysts’ tool chests. The model requires three inputs to compute expected returns – a riskfree rate, a beta for an asset and an expected risk premium for the market portfolio (over and above the riskfree rate). Betas are estimated, by most practitioners, by regressing returns on an asset against a stock index, with the slope of the regression being the b...

Estimates of radiation doses and cancer risk from food intake in Korea

International Nuclear Information System (INIS)

Moon, Eun Kyeong; Lee, Won Jin; Ha, Wi Ho; Seo, Song Won; Jin, Young Woo; Jeong, Kyu Hwan; Yoon, Hae Jung; Kim, Hyoung Soo; Hwang, Myung Sil; Choi, Hoon

2016-01-01

After the Fukushima Daiichi nuclear power plant accident, a widespread public concern for radiation exposure through the contamination of domestic or imported food has continued worldwide. Because the internal exposure from contaminated food is an important consideration for human health effect, some studies for estimating radiation doses and cancer risk from the Fukushima nuclear accident have been conducted in several countries (1). The aims of the study is to estimate internal radiation dose and lifetime risks of cancer from food ingestion in Korean population. Our findings suggest no discernible increase n radiation doses or excess fatal cancer risk from food ingestion at this stage in Korea, and provide scientific evidence of the risk communication with general public associated with low-dose radiation exposure.

Estimates of radiation doses and cancer risk from food intake in Korea

Energy Technology Data Exchange (ETDEWEB)

Moon, Eun Kyeong; Lee, Won Jin [Korea University, Seoul (Korea, Republic of); Ha, Wi Ho; Seo, Song Won; Jin, Young Woo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Jeong, Kyu Hwan [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Yoon, Hae Jung; Kim, Hyoung Soo; Hwang, Myung Sil [Ministry of Food and Drug Safety, Cheongju (Korea, Republic of); Choi, Hoon [Wonkwang University, Iksan (Korea, Republic of)

2016-04-15

After the Fukushima Daiichi nuclear power plant accident, a widespread public concern for radiation exposure through the contamination of domestic or imported food has continued worldwide. Because the internal exposure from contaminated food is an important consideration for human health effect, some studies for estimating radiation doses and cancer risk from the Fukushima nuclear accident have been conducted in several countries (1). The aims of the study is to estimate internal radiation dose and lifetime risks of cancer from food ingestion in Korean population. Our findings suggest no discernible increase n radiation doses or excess fatal cancer risk from food ingestion at this stage in Korea, and provide scientific evidence of the risk communication with general public associated with low-dose radiation exposure.

Drawbacks of the use of indirect estimates of renal function to evaluate the effect of risk factors on renal function

NARCIS (Netherlands)

Verhave, JC; Gansevoort, RT; Hillege, HL; De Zeeuw, D; Curhan, GC; De Jong, PE

Many epidemiologic studies presently aim to evaluate the effect of risk factors on renal function. As direct measurement of renal function is cumbersome to perform, epidentiologic studies generally use an indirect estimate of renal function. The consequences of using different methods of renal

Dose-stochastic radiobiological effect relationship in model of two reactions and estimation of radiation risk

International Nuclear Information System (INIS)

Komochkov, M.M.

1997-01-01

The model of dose-stochastic effect relationship for biological systems capable of self-defence under danger factor effect is developed. A defence system is realized in two forms of organism reaction, which determine innate μ n and adaptive μ a radiosensitivities. The significances of μ n are determined by host (inner) factors; and the significances of μ a , by external factors. The possibilities of adaptive reaction are determined by the coefficient of capabilities of the defence system. The formulas of the dose-effect relationship are the solutions of differential equations of assumed process in the defence system of organism. The model and formulas have been checked both at cell and at human levels. Based on the model and personal monitoring data, the estimation of radiation risk at the Joint Institute for Nuclear Research is done

Psychological impact of providing women with personalised 10-year breast cancer risk estimates.

Science.gov (United States)

French, David P; Southworth, Jake; Howell, Anthony; Harvie, Michelle; Stavrinos, Paula; Watterson, Donna; Sampson, Sarah; Evans, D Gareth; Donnelly, Louise S

2018-05-08

The Predicting Risk of Cancer at Screening (PROCAS) study estimated 10-year breast cancer risk for 53,596 women attending NHS Breast Screening Programme. The present study, nested within the PROCAS study, aimed to assess the psychological impact of receiving breast cancer risk estimates, based on: (a) the Tyrer-Cuzick (T-C) algorithm including breast density or (b) T-C including breast density plus single-nucleotide polymorphisms (SNPs), versus (c) comparison women awaiting results. A sample of 2138 women from the PROCAS study was stratified by testing groups: T-C only, T-C(+SNPs) and comparison women; and by 10-year risk estimates received: 'moderate' (5-7.99%), 'average' (2-4.99%) or 'below average' (<1.99%) risk. Postal questionnaires were returned by 765 (36%) women. Overall state anxiety and cancer worry were low, and similar for women in T-C only and T-C(+SNPs) groups. Women in both T-C only and T-C(+SNPs) groups showed lower-state anxiety but slightly higher cancer worry than comparison women awaiting results. Risk information had no consistent effects on intentions to change behaviour. Most women were satisfied with information provided. There was considerable variation in understanding. No major harms of providing women with 10-year breast cancer risk estimates were detected. Research to establish the feasibility of risk-stratified breast screening is warranted.

Risk estimates for bone

International Nuclear Information System (INIS)

Schlenker, R.A.

1982-01-01

Bone sarcoma data for 226 228 Ra and 224 Ra are analyzed within the dosage ranges where the observed risk is zero. The uncertainty in the risk may be effectively illustrated by using pairs of functions based on a statistically-based measure of confidence. For radiation protection, the appropriate measure of risk is cumulative incidence in the presence of competing risks, as this takes into account the reduction of radiation effects brought about by natural mortality

Assessment of Methods for Estimating Risk to Birds from ...

Science.gov (United States)

The U.S. EPA Ecological Risk Assessment Support Center (ERASC) announced the release of the final report entitled, Assessment of Methods for Estimating Risk to Birds from Ingestion of Contaminated Grit Particles. This report evaluates approaches for estimating the probability of ingestion by birds of contaminated particles such as pesticide granules or lead particles (i.e. shot or bullet fragments). In addition, it presents an approach for using this information to estimate the risk of mortality to birds from ingestion of lead particles. Response to ERASC Request #16

Estimation of the burden of cardiovascular disease attributable to modifiable risk factors and cost-effectiveness analysis of preventative interventions to reduce this burden in Argentina

Directory of Open Access Journals (Sweden)

Martí Sebastián

2010-10-01

Full Text Available Abstract Background Cardiovascular disease (CVD is the primary cause of mortality and morbidity in Argentina representing 34.2% of deaths and 12.6% of potential years of life lost (PYLL. The aim of the study was to estimate the burden of acute coronary heart disease (CHD and stroke and the cost-effectiveness of preventative population-based and clinical interventions. Methods An epidemiological model was built incorporating prevalence and distribution of high blood pressure, high cholesterol, hyperglycemia, overweight and obesity, smoking, and physical inactivity, obtained from the Argentine Survey of Risk Factors dataset. Population Attributable Fraction (PAF of each risk factor was estimated using relative risks from international sources. Total fatal and non-fatal events, PYLL and Disability Adjusted Life Years (DALY were estimated. Costs of event were calculated from local utilization databases and expressed in international dollars (I$. Incremental cost-effectiveness ratios (ICER were estimated for six interventions: reducing salt in bread, mass media campaign to promote tobacco cessation, pharmacological therapy of high blood pressure, pharmacological therapy of high cholesterol, tobacco cessation therapy with bupropion, and a multidrug strategy for people with an estimated absolute risk > 20% in 10 years. Results An estimated total of 611,635 DALY was lost due to acute CHD and stroke for 2005. Modifiable risk factors explained 71.1% of DALY and more than 80% of events. Two interventions were cost-saving: lowering salt intake in the population through reducing salt in bread and multidrug therapy targeted to persons with an absolute risk above 20% in 10 years; three interventions had very acceptable ICERs: drug therapy for high blood pressure in hypertensive patients not yet undergoing treatment (I$ 2,908 per DALY saved, mass media campaign to promote tobacco cessation amongst smokers (I$ 3,186 per DALY saved, and lowering cholesterol with

Translation of risk factor estimates into on-farm interventions and their effect on Campylobacter broiler flock prevalence

DEFF Research Database (Denmark)

Sommer, Helle Mølgaard; Nauta, Maarten; Rosenquist, Hanne

2016-01-01

population estimations using logistic regression. To obtain population estimates per country, the predicted prevalence values were multiplied by the frequencies (no. of farms) in a reference population based on data from the risk factor study and a large questionnaire. The latter was included to improve...... improve further when the results are integrated with costs of interventions in a cost effectiveness study. The approach was developed for Campylobacter in broiler flocks, but it can also be applied to other pathogens and other farm animals, given that the required data are available....

41 CFR 102-80.50 - Are Federal agencies responsible for identifying/estimating risks and for appropriate risk...

Science.gov (United States)

2010-07-01

... Environmental Management Risks and Risk Reduction Strategies § 102-80.50 Are Federal agencies responsible for... identify and estimate safety and environmental management risks and appropriate risk reduction strategies... responsible for identifying/estimating risks and for appropriate risk reduction strategies? 102-80.50 Section...

Bayesian estimation of covariance matrices: Application to market risk management at EDF

International Nuclear Information System (INIS)

Jandrzejewski-Bouriga, M.

2012-01-01

In this thesis, we develop new methods of regularized covariance matrix estimation, under the Bayesian setting. The regularization methodology employed is first related to shrinkage. We investigate a new Bayesian modeling of covariance matrix, based on hierarchical inverse-Wishart distribution, and then derive different estimators under standard loss functions. Comparisons between shrunk and empirical estimators are performed in terms of frequentist performance under different losses. It allows us to highlight the critical importance of the definition of cost function and show the persistent effect of the shrinkage-type prior on inference. In a second time, we consider the problem of covariance matrix estimation in Gaussian graphical models. If the issue is well treated for the decomposable case, it is not the case if you also consider non-decomposable graphs. We then describe a Bayesian and operational methodology to carry out the estimation of covariance matrix of Gaussian graphical models, decomposable or not. This procedure is based on a new and objective method of graphical-model selection, combined with a constrained and regularized estimation of the covariance matrix of the model chosen. The procedures studied effectively manage missing data. These estimation techniques were applied to calculate the covariance matrices involved in the market risk management for portfolios of EDF (Electricity of France), in particular for problems of calculating Value-at-Risk or in Asset Liability Management. (author)

Fatalities in high altitude mountaineering: a review of quantitative risk estimates.

Science.gov (United States)

Weinbruch, Stephan; Nordby, Karl-Christian

2013-12-01

Quantitative estimates for mortality in high altitude mountaineering are reviewed. Special emphasis is placed on the heterogeneity of the risk estimates and on confounding. Crude estimates for mortality are on the order of 1/1000 to 40/1000 persons above base camp, for both expedition members and high altitude porters. High altitude porters have mostly a lower risk than expedition members (risk ratio for all Nepalese peaks requiring an expedition permit: 0.73; 95 % confidence interval 0.59-0.89). The summit bid is generally the most dangerous part of an expedition for members, whereas most high altitude porters die during route preparation. On 8000 m peaks, the mortality during descent from summit varies between 4/1000 and 134/1000 summiteers (members plus porters). The risk estimates are confounded by human and environmental factors. Information on confounding by gender and age is contradictory and requires further work. There are indications for safety segregation of men and women, with women being more risk averse than men. Citizenship appears to be a significant confounder. Prior high altitude mountaineering experience in Nepal has no protective effect. Commercial expeditions in the Nepalese Himalayas have a lower mortality than traditional expeditions, though after controlling for confounding, the difference is not statistically significant. The overall mortality is increasing with increasing peak altitude for expedition members but not for high altitude porters. In the Nepalese Himalayas and in Alaska, a significant decrease of mortality with calendar year was observed. A few suggestions for further work are made at the end of the article.

Estimating internal exposure risks by the relative risk and the National Institute of Health risk models

International Nuclear Information System (INIS)

Mehta, S.K.; Sarangapani, R.

1995-01-01

This paper presents tabulations of risk (R) and person-years of life lost (PYLL) for acute exposures of individual organs at ages 20 and 40 yrs for the Indian and Japanese populations to illustrate the effect of age at exposure in the two models. Results are also presented for the organ wise nominal probability coefficients (NPC) and PYLL for individual organs for the age distributed Indian population by the two models. The results presented show that for all organs the estimates of PYLL and NPC for the Indian population are lower than those for the Japanese population by both models except for oesophagus, breast and ovary by the relative risk (RR) model, where the opposite trend is observed. The results also show that the Indian all-cancer values of NPC averaged over the two models is 2.9 x 10 -2 Sv -1 , significantly lower than the world average value of 5x10 -2 Sv -1 estimated by the ICRP. (author). 9 refs., 2 figs., 2 tabs

Revision of risk estimates and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

It has been apparent for some time that our estimates of the risks associated with exposure to ionizing radiation must be increased above those values reported by UNSCEAR in 1977 an dused by ICRP to form their present recommendations. NRPB foresaw some of these changes and introduced interim advice within the UK to restrict exposures of wordkers and members of the public to levels below the existing limits. Since that advice was given, UNSCEAR has produced a 1988 report reviewing human data to provide new estimates of risks associated with exposure at high doses and high doserates. These risk figures are up to 4 times higher than when UNSCEAR reported in 1977. In this paper, the reasons for the changes in the estimates of risk will be described and the current NRPB guidelines for risk factors for protection purposes will be presented. The implications of these new risk factors for the setting of dose limits will then be discussed. (Author). 10 refs.; 2 tabs

The estimation of small probabilities and risk assessment

International Nuclear Information System (INIS)

Kalbfleisch, J.D.; Lawless, J.F.; MacKay, R.J.

1982-01-01

The primary contribution of statistics to risk assessment is in the estimation of probabilities. Frequently the probabilities in question are small, and their estimation is particularly difficult. The authors consider three examples illustrating some problems inherent in the estimation of small probabilities

Russia-specific relative risks and their effects on the estimated alcohol-attributable burden of disease.

Science.gov (United States)

Shield, Kevin D; Rehm, Jürgen

2015-05-10

Alcohol consumption is a major risk factor for the burden of disease globally. This burden is estimated using Relative Risk (RR) functions for alcohol from meta-analyses that use data from all countries; however, for Russia and surrounding countries, country-specific risk data may need to be used. The objective of this paper is to compare the estimated burden of alcohol consumption calculated using Russia-specific alcohol RRs with the estimated burden of alcohol consumption calculated using alcohol RRs from meta-analyses. Data for 2012 on drinking indicators were calculated based on the Global Information System on Alcohol and Health. Data for 2012 on mortality, Years of Life Lost, Years Lived with Disability, and Disability-Adjusted Life Years (DALYs) lost by cause were obtained by country from the World Health Organization. Alcohol Population-Attributable Fractions (PAFs) were calculated based on a risk modelling methodology from Russia. These PAFs were compared to PAFs calculated using methods applied for all other countries. The 95% Uncertainty Intervals (UIs) for the alcohol PAFs were calculated using a Monte Carlo-like method. Using Russia-specific alcohol RR functions, in Russia in 2012 alcohol caused an estimated 231,900 deaths (95% UI: 185,600 to 278,200) (70,800 deaths among women and 161,100 deaths among men) and 13,295,000 DALYs lost (95% UI: 11,242,000 to 15,348,000) (3,670,000 DALYs lost among women and 9,625,000 DALYs lost among men) among people 0 to 64 years of age. This compares to an estimated 165,600 deaths (95% UI: 97,200 to 228,100) (29,700 deaths among women and 135,900 deaths among men) and 10,623,000 DALYs lost (95% UI: 7,265,000 to 13,754,000) (1,783,000 DALYs lost among women and 8,840,000 DALYs lost among men) among people 0 to 64 years of age caused by alcohol when non-Russia-specific alcohol RRs were used. Results indicate that if the Russia-specific RRs are used when estimating the health burden attributable to alcohol consumption in

Market Microstructure Effects on Firm Default Risk Evaluation

Directory of Open Access Journals (Sweden)

Flavia Barsotti

2016-07-01

Full Text Available Default probability is a fundamental variable determining the credit worthiness of a firm and equity volatility estimation plays a key role in its evaluation. Assuming a structural credit risk modeling approach, we study the impact of choosing different non parametric equity volatility estimators on default probability evaluation, when market microstructure noise is considered. A general stochastic volatility framework with jumps for the underlying asset dynamics is defined inside a Merton-like structural model. To estimate the volatility risk component of a firm we use high-frequency equity data: market microstructure noise is introduced as a direct effect of observing noisy high-frequency equity prices. A Monte Carlo simulation analysis is conducted to (i test the performance of alternative non-parametric equity volatility estimators in their capability of filtering out the microstructure noise and backing out the true unobservable asset volatility; (ii study the effects of different non-parametric estimation techniques on default probability evaluation. The impact of the non-parametric volatility estimators on risk evaluation is not negligible: a sensitivity analysis defined for alternative values of the leverage parameter and average jumps size reveals that the characteristics of the dataset are crucial to determine which is the proper estimator to consider from a credit risk perspective.

Schistosomiasis and water resources development: systematic review, meta-analysis, and estimates of people at risk.

Science.gov (United States)

Steinmann, Peter; Keiser, Jennifer; Bos, Robert; Tanner, Marcel; Utzinger, Jürg

2006-07-01

An estimated 779 million people are at risk of schistosomiasis, of whom 106 million (13.6%) live in irrigation schemes or in close proximity to large dam reservoirs. We identified 58 studies that examined the relation between water resources development projects and schistosomiasis, primarily in African settings. We present a systematic literature review and meta-analysis with the following objectives: (1) to update at-risk populations of schistosomiasis and number of people infected in endemic countries, and (2) to quantify the risk of water resources development and management on schistosomiasis. Using 35 datasets from 24 African studies, our meta-analysis showed pooled random risk ratios of 2.4 and 2.6 for urinary and intestinal schistosomiasis, respectively, among people living adjacent to dam reservoirs. The risk ratio estimate for studies evaluating the effect of irrigation on urinary schistosomiasis was in the range 0.02-7.3 (summary estimate 1.1) and that on intestinal schistosomiasis in the range 0.49-23.0 (summary estimate 4.7). Geographic stratification showed important spatial differences, idiosyncratic to the type of water resources development. We conclude that the development and management of water resources is an important risk factor for schistosomiasis, and hence strategies to mitigate negative effects should become integral parts in the planning, implementation, and operation of future water projects.

Use of GIS in the estimation and development of risk reduction technology

International Nuclear Information System (INIS)

Ha, Jae Joo

1998-03-01

The occurrence probability of a severe accident in the nuclear power plant is very small because the safety of a plant and the public is considered in the design and operation of a nuclear power plant. However, if a severe accident occurs, the establishment of a reduction strategy of damages resulting from it is essential because the effect of it on the human and the environment is very large. The important criterion which determines the severity of an accident is risk, which is defined as the product of its frequently and the consequence. The establishment of countermeasures in order to estimate and reduce risks quantitatively can be a very powerful tool to minimize the effect of an accident on the human and the environment. The research on the establishment of a framework which integrates a geographic information system (GIS), a database management system (DBMS), and decision making support system (DMSS) is considered very actively. Based on these systems, we can accomplish the estimation and display of risks and the development of reduction methodologies which are essential parts of an accident management of a nuclear power plant. The GIS plays a role to support users to systematize and comprehend spatial relationships of information which are necessary for the decision making. Through the DBMS, we can establish and manage spatial and attribute data, and use them in the query and selection. The DMSS is a computer-based information system which makes a necessary decision easily. In this study, we reviewed the fundamental concepts of a GIS and examined the methodology for the use of it in the estimation and display of risks. Also, we established the fundamental GIS platform of a Yonggwang site and the necessary database systems for the estimation of risks. (author). 17 refs., 9 tabs., 34 figs

Best-Estimates in Bond Markets with Reinvestment Risk

Directory of Open Access Journals (Sweden)

Anne MacKay

2015-07-01

Full Text Available The concept of best-estimate, prescribed by regulators to value insurance liabilities for accounting and solvency purposes, has recently been discussed extensively in the industry and related academic literature. To differentiate hedgeable and non-hedgeable risks in a general case, recent literature defines best-estimates using orthogonal projections of a claim on the space of replicable payoffs. In this paper, we apply this concept of best-estimate to long-maturity claims in a market with reinvestment risk, since in this case the total liability cannot easily be separated into hedgeable and non-hedgeable parts. We assume that a limited number of short-maturity bonds are traded, and derive the best-estimate price of bonds with longer maturities, thus obtaining a best-estimate yield curve. We therefore use the multifactor Vasiˇcek model and derive within this framework closed-form expressions for the best-estimate prices of long-term bonds.

New risk estimates at low doses

International Nuclear Information System (INIS)

Fry, R.J.M.

1992-01-01

The age of molecular radiation epidemiology may be at hand. The techniques are available to establish with the degree of precision required to determine whether agent-specific mutations can be identified consistently. A concerted effort to examine radiation-induced changes in as many relevant genes as possible appears to be justified. Cancers in those exposed to low doses of ionizing radiation should be chosen for the investigation. Parallel studies of radiation-induced cancers in experimental animals would not only complement the human studies, but perhaps reveal approaches to extrapolation of risk estimates across species. A caveat should be added to this optimistic view of what molecular studies might contribute to the knotty problem of risk estimates at low doses. The suggestions are made by one with no expertise in the field of molecular biology

Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

Energy Technology Data Exchange (ETDEWEB)

Brodin, N. Patrik (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark); Niels Bohr Inst., Faculty of Sciences, Univ. of Copenhagen (Denmark)), e-mail: brodin.patrik@gmail.com; Munck af Rosenschoeld, Per; Aznar, Marianne C.; Vogelius, Ivan R. (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark)); Kiil-Berthelsen, Anne (Radiation Medicine Research Center, Dept. of Radiation Oncology, Rigshospitalet, Univ. of Copenhagen (Denmark); Dept. of Clinical Physiology and Nuclear Medicine, Centre of Diagnostic Investigations, Rigshospitalet, Univ. of Copenhagen (Denmark)); Nilsson, Per; Bjoerk-Eriksson, Thomas (Dept. of Oncology, Skaane Univ. Hospital and Lund Univ., Lund (Sweden)); Lannering, Birgitta (Dept. of Paediatric Oncology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden))

2011-08-15

Introduction. The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc (RA)) or spot-scanned intensity-modulated proton therapy (IMPT). The aim was also to find dose-volume toxicity parameters relevant to children undergoing RT to be used in the inverse planning of RA and IMPT, and to use in the risk estimations. Material and methods. Treatment plans were created for all three techniques on 10 pediatric patients that have been treated with craniospinal irradiation (CSI) at our institution in 2007-2009. Plans were generated for two prescription CSI doses, 23.4 Gy and 36 Gy. Risk estimates were based on childhood cancer survivor data when available and secondary cancer (SC) risks were estimated as a function of age at exposure and attained age according to the organ-equivalent dose (OED) concept. Results. Estimates of SC risk was higher for the RA plans and differentiable from the estimates for 3D CRT at attained ages above 40 years. The risk of developing heart failure, hearing loss, hypothyroidism and xerostomia was highest for the 3D CRT plans. The risks of all adverse effects were estimated as lowest for the IMPT plans, even when including secondary neutron (SN) irradiation with high values of the neutron radiation weighting factors (WR{sub neutron}). Conclusions. When comparing RA and 3D CRT treatment for pediatric MB it is a matter of comparing higher SC risk against higher risks of non-cancer adverse events. Considering time until onset of the different complications is necessary to fully assess patient benefit in such a comparison. The IMPT plans, including SN dose contribution, compared favorably to the photon techniques in terms of all radiobiological risk estimates

Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

International Nuclear Information System (INIS)

Brodin, N. Patrik; Munck af Rosenschoeld, Per; Aznar, Marianne C.; Vogelius, Ivan R.; Kiil-Berthelsen, Anne; Nilsson, Per; Bjoerk-Eriksson, Thomas; Lannering, Birgitta

2011-01-01

Introduction. The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc (RA)) or spot-scanned intensity-modulated proton therapy (IMPT). The aim was also to find dose-volume toxicity parameters relevant to children undergoing RT to be used in the inverse planning of RA and IMPT, and to use in the risk estimations. Material and methods. Treatment plans were created for all three techniques on 10 pediatric patients that have been treated with craniospinal irradiation (CSI) at our institution in 2007-2009. Plans were generated for two prescription CSI doses, 23.4 Gy and 36 Gy. Risk estimates were based on childhood cancer survivor data when available and secondary cancer (SC) risks were estimated as a function of age at exposure and attained age according to the organ-equivalent dose (OED) concept. Results. Estimates of SC risk was higher for the RA plans and differentiable from the estimates for 3D CRT at attained ages above 40 years. The risk of developing heart failure, hearing loss, hypothyroidism and xerostomia was highest for the 3D CRT plans. The risks of all adverse effects were estimated as lowest for the IMPT plans, even when including secondary neutron (SN) irradiation with high values of the neutron radiation weighting factors (WR neutron ). Conclusions. When comparing RA and 3D CRT treatment for pediatric MB it is a matter of comparing higher SC risk against higher risks of non-cancer adverse events. Considering time until onset of the different complications is necessary to fully assess patient benefit in such a comparison. The IMPT plans, including SN dose contribution, compared favorably to the photon techniques in terms of all radiobiological risk estimates

Methods to estimate the genetic risk

International Nuclear Information System (INIS)

Ehling, U.H.

1989-01-01

The estimation of the radiation-induced genetic risk to human populations is based on the extrapolation of results from animal experiments. Radiation-induced mutations are stochastic events. The probability of the event depends on the dose; the degree of the damage dose not. There are two main approaches in making genetic risk estimates. One of these, termed the direct method, expresses risk in terms of expected frequencies of genetic changes induced per unit dose. The other, referred to as the doubling dose method or the indirect method, expresses risk in relation to the observed incidence of genetic disorders now present in man. The advantage of the indirect method is that not only can Mendelian mutations be quantified, but also other types of genetic disorders. The disadvantages of the method are the uncertainties in determining the current incidence of genetic disorders in human and, in addition, the estimasion of the genetic component of congenital anomalies, anomalies expressed later and constitutional and degenerative diseases. Using the direct method we estimated that 20-50 dominant radiation-induced mutations would be expected in 19 000 offspring born to parents exposed in Hiroshima and Nagasaki, but only a small proportion of these mutants would have been detected with the techniques used for the population study. These methods were used to predict the genetic damage from the fallout of the reactor accident at Chernobyl in the vicinity of Southern Germany. The lack of knowledge for the interaction of chemicals with ionizing radiation and the discrepancy between the high safety standards for radiation protection and the low level of knowledge for the toxicological evaluation of chemical mutagens will be emphasized. (author)

Effect of Using Different Vehicle Weight Groups on the Estimated Relationship Between Mass Reduction and U.S. Societal Fatality Risk per Vehicle Miles of Travel

Energy Technology Data Exchange (ETDEWEB)

Wenzel, Tom P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Technologies Area. Building Technology and Urban Systems Division

2016-08-22

This report recalculates the estimated relationship between vehicle mass and societal fatality risk, using alternative groupings by vehicle weight, to test whether the trend of decreasing fatality risk from mass reduction as case vehicle mass increases, holds over smaller increments of the range in case vehicle masses. The NHTSA baseline regression model estimates the relationship using for two weight groups for cars and light trucks; we re-estimated the mass reduction coefficients using four, six, and eight bins of vehicle mass. The estimated effect of mass reduction on societal fatality risk was not consistent over the range in vehicle masses in these weight bins. These results suggest that the relationship indicated by the NHTSA baseline model is a result of other, unmeasured attributes of the mix of vehicles in the lighter vs. heavier weight bins, and not necessarily the result of a correlation between mass reduction and societal fatality risk. An analysis of the average vehicle, driver, and crash characteristics across the various weight groupings did not reveal any strong trends that might explain the lack of a consistent trend of decreasing fatality risk from mass reduction in heavier vehicles.

Estimating cancer risk from outdoor concentrations of hazardous air pollutants in 1990

Energy Technology Data Exchange (ETDEWEB)

Woodruff, T.J.; Caldwell, J.; Cogliano, V.J.; Axelrad, D.A.

2000-03-01

A public health concern regarding hazardous air pollutants (HAPs) is their potential to cause cancer. It has been difficult to assess potential cancer risks from HAPs, due primarily to lack of ambient concentration data for the general population. The Environmental Protection Agency's Cumulative Exposure Project modeled 1990 outdoor concentrations of HAPs across the United States, which were combined with inhalation unit risk estimates to estimate the potential increase in excess cancer risk for individual carcinogenic HAPs. These were summed3d to provide an estimate of cancer risk from multiple HAPs. The analysis estimates a median excess cancer risk of 18 lifetime cancer cases per 100,000 people for all HAP concentrations. About 75% of estimated cancer risk was attributable to exposure to polycyclic organic matter, 1,3-butadiene, formaldehyde, benzene, and chromium. Consideration of some specific uncertainties, including underestimation of ambient concentrations, combining upper 95% confidence bound potency estimates, and changes to potency estimates, found that cancer risk may be underestimated by 15% or overestimated by 40--50%. Other unanalyzed uncertainties could make these under- or overestimates larger. This analysis used 1990 estimates of concentrations and can be used to track progress toward reducing cancer risk to the general population.

Probabilistic fuzzy systems in value-at-risk estimation

NARCIS (Netherlands)

Almeida, R.J.; Kaymak, U.

2009-01-01

Value-at-risk (VaR) is a popular measure for quantifying the market risk that a financial institution faces into a single number. Owing to the complexity of financial markets, the risks associated with a portfolio varies over time. Consequently, advanced methods of VaR estimation use parametric

An interim UK response to revised risk estimates

International Nuclear Information System (INIS)

Beaver, P.F.; Bines, W.P.

1992-01-01

This paper describes the legal framework in place when the revised risk estimates were announced by the International Commission for Radiological Protection (ICRP) in 1987 and how an addition to that framework enabled the revised risk estimates to be taken into account when making decisions about radiation protection practice both at plant and individual worker level. It is suggested that this a may be an early example of the use of a constraint applied generically. (author)

Risk Estimates and Risk Factors Related to Psychiatric Inpatient Suicide

DEFF Research Database (Denmark)

Madsen, Trine; Erlangsen, Annette; Nordentoft, Merete

2017-01-01

trends, and socio-demographic and clinical risk factors of suicide in psychiatric inpatients. Psychiatric inpatients have a very high risk of suicide relative to the background population, but it remains challenging for clinicians to identify those patients that are most likely to die from suicide during......People with mental illness have an increased risk of suicide. The aim of this paper is to provide an overview of suicide risk estimates among psychiatric inpatients based on the body of evidence found in scientific peer-reviewed literature; primarily focusing on the relative risks, rates, time...... admission. Most studies are based on low power, thus compromising quality and generalisability. The few studies with sufficient statistical power mainly identified non-modifiable risk predictors such as male gender, diagnosis, or recent deliberate self-harm. Also, the predictive value of these predictors...

Risk Estimates and Risk Factors Related to Psychiatric Inpatient Suicide

DEFF Research Database (Denmark)

Madsen, Trine; Erlangsen, Annette; Nordentoft, Merete

2017-01-01

People with mental illness have an increased risk of suicide. The aim of this paper is to provide an overview of suicide risk estimates among psychiatric inpatients based on the body of evidence found in scientific peer-reviewed literature; primarily focusing on the relative risks, rates, time...... trends, and socio-demographic and clinical risk factors of suicide in psychiatric inpatients. Psychiatric inpatients have a very high risk of suicide relative to the background population, but it remains challenging for clinicians to identify those patients that are most likely to die from suicide during...... is low. It would be of great benefit if future studies would be based on large samples while focusing on modifiable predictors over the course of an admission, such as hopelessness, depressive symptoms, and family/social situations. This would improve our chances of developing better risk assessment...

Adequacy of relative and absolute risk models for lifetime risk estimate of radiation-induced cancer

International Nuclear Information System (INIS)

McBride, M.; Coldman, A.J.

1988-03-01

This report examines the applicability of the relative (multiplicative) and absolute (additive) models in predicting lifetime risk of radiation-induced cancer. A review of the epidemiologic literature, and a discussion of the mathematical models of carcinogenesis and their relationship to these models of lifetime risk, are included. Based on the available data, the relative risk model for the estimation of lifetime risk is preferred for non-sex-specific epithelial tumours. However, because of lack of knowledge concerning other determinants of radiation risk and of background incidence rates, considerable uncertainty in modelling lifetime risk still exists. Therefore, it is essential that follow-up of exposed cohorts be continued so that population-based estimates of lifetime risk are available

Seismic Risk Assessment and Loss Estimation for Tbilisi City

Science.gov (United States)

Tsereteli, Nino; Alania, Victor; Varazanashvili, Otar; Gugeshashvili, Tengiz; Arabidze, Vakhtang; Arevadze, Nika; Tsereteli, Emili; Gaphrindashvili, Giorgi; Gventcadze, Alexander; Goguadze, Nino; Vephkhvadze, Sophio

2013-04-01

The proper assessment of seismic risk is of crucial importance for society protection and city sustainable economic development, as it is the essential part to seismic hazard reduction. Estimation of seismic risk and losses is complicated tasks. There is always knowledge deficiency on real seismic hazard, local site effects, inventory on elements at risk, infrastructure vulnerability, especially for developing countries. Lately great efforts was done in the frame of EMME (earthquake Model for Middle East Region) project, where in the work packages WP1, WP2 , WP3 and WP4 where improved gaps related to seismic hazard assessment and vulnerability analysis. Finely in the frame of work package wp5 "City Scenario" additional work to this direction and detail investigation of local site conditions, active fault (3D) beneath Tbilisi were done. For estimation economic losses the algorithm was prepared taking into account obtained inventory. The long term usage of building is very complex. It relates to the reliability and durability of buildings. The long term usage and durability of a building is determined by the concept of depreciation. Depreciation of an entire building is calculated by summing the products of individual construction unit' depreciation rates and the corresponding value of these units within the building. This method of calculation is based on an assumption that depreciation is proportional to the building's (constructions) useful life. We used this methodology to create a matrix, which provides a way to evaluate the depreciation rates of buildings with different type and construction period and to determine their corresponding value. Finally loss was estimated resulting from shaking 10%, 5% and 2% exceedance probability in 50 years. Loss resulting from scenario earthquake (earthquake with possible maximum magnitude) also where estimated.

Neoplastic potential of gastric irradiation. IV. Risk estimates

International Nuclear Information System (INIS)

Griem, M.L.; Justman, J.; Weiss, L.

1984-01-01

No significant tumor increase was found in the initial analysis of patients irradiated for peptic ulcer and followed through 1962. A preliminary study was undertaken 22 years later to estimate the risk of cancer due to gastric irradiation for peptic ulcer disease. A population of 2,049 irradiated patients and 763 medically managed patients has been identified. A relative risk of 3.7 was found for stomach cancer and an initial risk estimate of 5.5 x 10(-6) excess stomach cancers per person rad was calculated. A more complete follow-up is in progress to further elucidate this observation and decrease the ascertainment bias; however, preliminary data are in agreement with the Japanese atomic bomb reports

Emerging infectious disease outbreaks: estimating disease risk in Australian blood donors travelling overseas.

Science.gov (United States)

Coghlan, A; Hoad, V C; Seed, C R; Flower, R Lp; Harley, R J; Herbert, D; Faddy, H M

2018-01-01

International travel assists spread of infectious pathogens. Australians regularly travel to South-eastern Asia and the isles of the South Pacific, where they may become infected with infectious agents, such as dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) viruses that pose a potential risk to transfusion safety. In Australia, donors are temporarily restricted from donating for fresh component manufacture following travel to many countries, including those in this study. We aimed to estimate the unmitigated transfusion-transmission (TT) risk from donors travelling internationally to areas affected by emerging infectious diseases. We used the European Up-Front Risk Assessment Tool, with travel and notification data, to estimate the TT risk from donors travelling to areas affected by disease outbreaks: Fiji (DENV), Bali (DENV), Phuket (DENV), Indonesia (CHIKV) and French Polynesia (ZIKV). We predict minimal risk from travel, with the annual unmitigated risk of an infected component being released varying from 1 in 1·43 million to disease outbreak areas to source plasma collection provides a simple and effective risk management approach. © 2017 International Society of Blood Transfusion.

Multiple imputation for estimating the risk of developing dementia and its impact on survival.

Science.gov (United States)

Yu, Binbing; Saczynski, Jane S; Launer, Lenore

2010-10-01

Dementia, Alzheimer's disease in particular, is one of the major causes of disability and decreased quality of life among the elderly and a leading obstacle to successful aging. Given the profound impact on public health, much research has focused on the age-specific risk of developing dementia and the impact on survival. Early work has discussed various methods of estimating age-specific incidence of dementia, among which the illness-death model is popular for modeling disease progression. In this article we use multiple imputation to fit multi-state models for survival data with interval censoring and left truncation. This approach allows semi-Markov models in which survival after dementia depends on onset age. Such models can be used to estimate the cumulative risk of developing dementia in the presence of the competing risk of dementia-free death. Simulations are carried out to examine the performance of the proposed method. Data from the Honolulu Asia Aging Study are analyzed to estimate the age-specific and cumulative risks of dementia and to examine the effect of major risk factors on dementia onset and death.

Value at risk estimation with entropy-based wavelet analysis in exchange markets

Science.gov (United States)

He, Kaijian; Wang, Lijun; Zou, Yingchao; Lai, Kin Keung

2014-08-01

In recent years, exchange markets are increasingly integrated together. Fluctuations and risks across different exchange markets exhibit co-moving and complex dynamics. In this paper we propose the entropy-based multivariate wavelet based approaches to analyze the multiscale characteristic in the multidimensional domain and improve further the Value at Risk estimation reliability. Wavelet analysis has been introduced to construct the entropy-based Multiscale Portfolio Value at Risk estimation algorithm to account for the multiscale dynamic correlation. The entropy measure has been proposed as the more effective measure with the error minimization principle to select the best basis when determining the wavelet families and the decomposition level to use. The empirical studies conducted in this paper have provided positive evidence as to the superior performance of the proposed approach, using the closely related Chinese Renminbi and European Euro exchange market.

Measurement of total risk of spontaneous abortion: the virtue of conditional risk estimation

DEFF Research Database (Denmark)

Modvig, J; Schmidt, L; Damsgaard, M T

1990-01-01

The concepts, methods, and problems of measuring spontaneous abortion risk are reviewed. The problems touched on include the process of pregnancy verification, the changes in risk by gestational age and maternal age, and the presence of induced abortions. Methods used in studies of spontaneous...... abortion risk include biochemical assays as well as life table technique, although the latter appears in two different forms. The consequences of using either of these are discussed. It is concluded that no study design so far is appropriate for measuring the total risk of spontaneous abortion from early...... conception to the end of the 27th week. It is proposed that pregnancy may be considered to consist of two or three specific periods and that different study designs should concentrate on measuring the conditional risk within each period. A careful estimate using this principle leads to an estimate of total...

Dose dependence on stochastic radiobiological effect in radiation risk estimation

International Nuclear Information System (INIS)

Komochkov, M.M.

1999-01-01

The analysis of the results in dose -- effect relationship observation has been carried out on the cell and organism levels, with the aim to obtain more precise data on the risk coefficients at low doses. The results are represented by two contrasting groups of dose dependence on effect: a downwards concave and a J-shaped curve. Both types of dependence are described by the equation solutions of an assumed unified protective mechanism, which comprises two components: constitutive and adaptive or inducible ones. The latest data analysis of the downwards concave dependence curves shows a considerable underestimation of radiation risk in all types of cancer, except leukemia, for a number of critical groups in a population, at low doses comparing to the ICRP recommendations. With the dose increase, the decrease of the effect value per dose unit is observed. It may be possibly related to the switching of the activity of the adaptive protective mechanism, with some threshold dose values being exceeded

Comparison of additive (absolute) risk projection models and multiplicative (relative) risk projection models in estimating radiation-induced lifetime cancer risk

International Nuclear Information System (INIS)

Kai, Michiaki; Kusama, Tomoko

1990-01-01

Lifetime cancer risk estimates depend on risk projection models. While the increasing lengths of follow-up observation periods of atomic bomb survivors in Hiroshima and Nagasaki bring about changes in cancer risk estimates, the validity of the two risk projection models, the additive risk projection model (AR) and multiplicative risk projection model (MR), comes into question. This paper compares the lifetime risk or loss of life-expectancy between the two projection models on the basis of BEIR-III report or recently published RERF report. With Japanese cancer statistics the estimates of MR were greater than those of AR, but a reversal of these results was seen when the cancer hazard function for India was used. When we investigated the validity of the two projection models using epidemiological human data and animal data, the results suggested that MR was superior to AR with respect to temporal change, but there was little evidence to support its validity. (author)

Estimating the re-identification risk of clinical data sets

Directory of Open Access Journals (Sweden)

Dankar Fida

2012-07-01

Full Text Available Abstract Background De-identification is a common way to protect patient privacy when disclosing clinical data for secondary purposes, such as research. One type of attack that de-identification protects against is linking the disclosed patient data with public and semi-public registries. Uniqueness is a commonly used measure of re-identification risk under this attack. If uniqueness can be measured accurately then the risk from this kind of attack can be managed. In practice, it is often not possible to measure uniqueness directly, therefore it must be estimated. Methods We evaluated the accuracy of uniqueness estimators on clinically relevant data sets. Four candidate estimators were identified because they were evaluated in the past and found to have good accuracy or because they were new and not evaluated comparatively before: the Zayatz estimator, slide negative binomial estimator, Pitman’s estimator, and mu-argus. A Monte Carlo simulation was performed to evaluate the uniqueness estimators on six clinically relevant data sets. We varied the sampling fraction and the uniqueness in the population (the value being estimated. The median relative error and inter-quartile range of the uniqueness estimates was measured across 1000 runs. Results There was no single estimator that performed well across all of the conditions. We developed a decision rule which selected between the Pitman, slide negative binomial and Zayatz estimators depending on the sampling fraction and the difference between estimates. This decision rule had the best consistent median relative error across multiple conditions and data sets. Conclusion This study identified an accurate decision rule that can be used by health privacy researchers and disclosure control professionals to estimate uniqueness in clinical data sets. The decision rule provides a reliable way to measure re-identification risk.

Estimated risk of radiation-induced cancer from paediatric chest CT: two-year cohort study

Energy Technology Data Exchange (ETDEWEB)

Niemann, Tilo [Cantonal Hospital Baden, Department of Radiology, Baden (Switzerland); University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Colas, Lucie; Santangelo, Teresa; Faivre, Jean Baptiste; Remy, Jacques; Remy-Jardin, Martine [University Lille Nord de France, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Roser, Hans W.; Bremerich, Jens [University of Basel Hospital, Clinic of Radiology and Nuclear Medicine, Medical Physics, Basel (Switzerland)

2015-03-01

The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation. To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient cohort. A two-year cohort of 522 paediatric helical chest CT scans acquired using a dedicated low-dose protocol were analysed retrospectively. Patient-specific estimations of radiation doses were modelled using three different mathematical phantoms. Per-organ attributable cancer risk was then estimated using epidemiological models. Additional comparison was provided for naturally occurring risks. Total lifetime attributable risk of cancer incidence remains low for all age and sex categories, being highest in female neonates (0.34%). Summation of all cancer sites analysed raised the relative lifetime attributable risk of organ cancer incidence up to 3.6% in female neonates and 2.1% in male neonates. Using dedicated scan protocols, total lifetime attributable risk of cancer incidence and mortality for chest CT is estimated low for paediatric chest CT, being highest for female neonates. (orig.)

Estimates of health risk from exposure to radioactive pollutants

International Nuclear Information System (INIS)

Sullivan, R.E.; Nelson, N.S.; Ellett, W.H.; Dunning, D.E. Jr.; Leggett, R.W.; Yalcintas, M.G.; Eckerman, K.F.

1981-11-01

A dosimetric and health effects analysis has been performed for the Office of Radiation Programs of the Environmental Protection Agency (EPA) to assess potential hazards from radioactive pollutants. Contemporary dosimetric methods were used to obtain estimates of dose rates to reference organs from internal exposures due to either inhalation of contaminated air or ingestion of contaminated food, or from external exposures due to either immersion in contaminated air or proximity to contaminated ground surfaces. These dose rates were then used to estimate the number of premature cancer deaths arising from such exposures and the corresponding number of years of life lost in a cohort of 100,000 persons, all simultaneously liveborn and all going through life with the same risks of dying from competing causes. The risk of dying from a competing cause for a given year was taken to be the probability of dying from all causes as given in a recent actuarial life table for the total US popula six times larger than the first reservoir.onunding. Analytical work cthe Department of Energy

Estimating and mapping the population at risk of sleeping sickness.

Directory of Open Access Journals (Sweden)

Pere P Simarro

Full Text Available Human African trypanosomiasis (HAT, also known as sleeping sickness, persists as a public health problem in several sub-Saharan countries. Evidence-based, spatially explicit estimates of population at risk are needed to inform planning and implementation of field interventions, monitor disease trends, raise awareness and support advocacy. Comprehensive, geo-referenced epidemiological records from HAT-affected countries were combined with human population layers to map five categories of risk, ranging from "very high" to "very low," and to estimate the corresponding at-risk population.Approximately 70 million people distributed over a surface of 1.55 million km(2 are estimated to be at different levels of risk of contracting HAT. Trypanosoma brucei gambiense accounts for 82.2% of the population at risk, the remaining 17.8% being at risk of infection from T. b. rhodesiense. Twenty-one million people live in areas classified as moderate to very high risk, where more than 1 HAT case per 10,000 inhabitants per annum is reported.Updated estimates of the population at risk of sleeping sickness were made, based on quantitative information on the reported cases and the geographic distribution of human population. Due to substantial methodological differences, it is not possible to make direct comparisons with previous figures for at-risk population. By contrast, it will be possible to explore trends in the future. The presented maps of different HAT risk levels will help to develop site-specific strategies for control and surveillance, and to monitor progress achieved by ongoing efforts aimed at the elimination of sleeping sickness.

Estimation of second primary cancers risk based on the treatment planning system

International Nuclear Information System (INIS)

Jin Chufeng; Sun Guangyao; Liu Hui; Zheng Huaqing; Cheng Mengyun; Li Gui; Wu Yican; FDS Team

2011-01-01

Estimates of second primary cancers risk after radiotherapy has become increasingly important for comparative treatment planning. A new method based on the treatment planning system to estimate the risk of second primary cancers was introduced in this paper. Using the Advanced/Accurate Radiotherapy Treatment System(ARTS), a treatment planning system developed by the FDS team,the risk of second primary cancer was estimated over two treatment plans for a patient with pancreatic cancer. Based on the second primary cancer risk, the two plans were compared. It was found that,kidney and gall-bladder had higher risk to develop second primary cancer. A better plan was chosen by the analysis of second primary cancer risk. The results showed that this risk estimation method we developed could be used to evaluate treatment plans. (authors)

Annual effective dose due to residential radon progeny in Sweden: Evaluations based on current risk projections models and on risk estimates from a nation-wide Swedish epidemiological study

Energy Technology Data Exchange (ETDEWEB)

Doi, M [National Inst. of Radiological Sciences, Chiba (Japan); Lagarde, F [Karolinska Inst., Stockholm (Sweden). Inst. of Environmental Medicine; Falk, R; Swedjemark, G A [Swedish Radiation Protection Inst., Stockholm (Sweden)

1996-12-01

Effective dose per unit radon progeny exposure to Swedish population in 1992 is estimated by the risk projection model based on the Swedish epidemiological study of radon and lung cancer. The resulting values range from 1.29 - 3.00 mSv/WLM and 2.58 - 5.99 mSv/WLM, respectively. Assuming a radon concentration of 100 Bq/m{sup 3}, an equilibrium factor of 0.4 and an occupancy factor of 0.6 in Swedish houses, the annual effective dose for the Swedish population is estimated to be 0.43 - 1.98 mSv/year, which should be compared to the value of 1.9 mSv/year, according to the UNSCEAR 1993 report. 27 refs, tabs, figs.

Annual effective dose due to residential radon progeny in Sweden: Evaluations based on current risk projections models and on risk estimates from a nation-wide Swedish epidemiological study

International Nuclear Information System (INIS)

Doi, M.; Lagarde, F.

1996-12-01

Effective dose per unit radon progeny exposure to Swedish population in 1992 is estimated by the risk projection model based on the Swedish epidemiological study of radon and lung cancer. The resulting values range from 1.29 - 3.00 mSv/WLM and 2.58 - 5.99 mSv/WLM, respectively. Assuming a radon concentration of 100 Bq/m 3 , an equilibrium factor of 0.4 and an occupancy factor of 0.6 in Swedish houses, the annual effective dose for the Swedish population is estimated to be 0.43 - 1.98 mSv/year, which should be compared to the value of 1.9 mSv/year, according to the UNSCEAR 1993 report. 27 refs, tabs, figs

Estimation of lifetime cumulative incidence and mortality risk of gastric cancer.

Science.gov (United States)

Taniyama, Yukari; Katanoda, Kota; Charvat, Hadrien; Hori, Megumi; Ohno, Yuko; Sasazuki, Shizuka; Tsugane, Shoichiro

2017-11-01

To estimate cumulative incidence and mortality risk for gastric cancer by risk category. Risk was classified into four types according to the presence/absence of Helicobacter pylori infection and chronic atrophic gastritis: in order of lowest to highest risk, Group A: H. pylori(-) and atrophic gastritis(-); Group B: H. pylori(+) and atrophic gastritis(-); Group C:H. pylori(+) and atrophic gastritis(+); and, Group D: H. pylori(-) and atrophic gastritis(+). We used vital statistics for the crude all-cause and crude gastric cancer mortality rates in 2011 and data from population-based cancer registries (the Monitoring of Cancer Incidence in Japan) for gastric cancer incidence in 2011. For relative risk and prevalence, we used the results of a meta-analysis integrating previous studies and data from the Japan Public Health Center-based Prospective Study for the Next Generation, respectively (baseline survey 2011-16). We calculated the crude incidence and mortality rates and estimated the cumulative risk using a life-table method. The estimated lifetime cumulative incidence risk was 11.4% for men and 5.7% for women. The estimated risk for Groups A, B, C and D was 2.4%, 10.8%, 26.7% and 35.5% for men, and 1.2%, 5.5%, 13.5% and 18.0% for women, respectively. Similarly, the estimated lifetime cumulative mortality risk was 3.9% for men and 1.8% for women. The estimated risk of mortality for Groups A, B, C and D was 0.8%, 3.6%, 9.0% and 12.0% for men, and 0.4%, 1.7%, 4.2% and 5.7% for women, respectively. Our results may be useful for designing individually tailored prevention programs. © The Author 2017. Published by Oxford University Press.

Estimating risk at a Superfund site contaminated with radiological and chemical wastes

International Nuclear Information System (INIS)

Temeshy, A.; Liedle, J.M.; Sims, L.M.; Efird, C.R.

1992-01-01

This paper describes the method and results for estimating carcinogenic and noncarcinogenic effects at a Superfund site that is radiologically and chemically contaminated. Risk to receptors from disposal of waste in soil and resulting contamination of groundwater, air, surface water, and sediment is quantified. Specific risk assessment components which are addressed are the exposure assessment, toxicity assessment, and the resulting risk characterization. In the exposure assessment, potential exposure pathways are identified using waste disposal inventory information for soil and modeled information for other media. Models are used to calculate future radionuclide concentrations in groundwater, soil, surface water and air. Chemical exposure concentrations are quantified using site characterization data. Models are used to determine concentrations of chemicals in surface water and in air. Toxicity parameters used to quantify the dose-response relationship associated with the carcinogenic contaminants are slope factors and with noncarcinogenic contaminants are reference doses. In the risk characterization step, results from the exposure assessment and toxicity assessment are summarized and integrated into quantitative risk estimates for carcinogens and hazard induces for noncarcinogens. Calculated risks for carcinogenic contaminants are compared with EPA's target risk range. At WAG 6, the risk from radionuclides and chemicals for an on-WAG homesteader exceeds EPA's target risk range. Hazard indices are compared to unity for noncarcinogenic contaminants. At WAG 6, the total pathway hazard index for the on-WAG homesteader exceeds unity

Bomb survivor selection and consequences for estimates of population cancer risks

International Nuclear Information System (INIS)

Little, M.P.; Charles, M.W.

1990-01-01

Health records of the Japanese bomb survivor population [with the 1965 (T65D) and 1986 (DS86) dosimetry systems] have been analyzed and some evidence found for the selection effect hypothesized by Stewart and Kneale. This is found to be significant in only the first of the periods examined (1950-1958), and the effect diminishes in magnitude thereafter. There are indications that the effect might be an artifact of the T65D dosimetry, in which it is observed more strongly than in the DS86 data. There is no evidence to suggest that selection on this basis might confer correspondingly reduced susceptibility to radiation-induced cancer. If, however, one makes this assumption, as suggested by Stewart and Kneale, then current estimates of population cancer risks might need to be inflated by between 5% and 35% (for excess cancer deaths, Gy-1) or between 8% and 40% (for years of life lost, Gy-1) to account for this. It is likely that these figures, even assuming them not to be simply an artifact of the T65D dosimetry, overestimate the degree of adjustment required to the risk estimates

Stochastic risk estimation from medical x-ray diagnostic examinations, 3

International Nuclear Information System (INIS)

Hashizume, Tadashi; Maruyama, Takashi; Noda, Yutaka; Iwai, Kazuo; Fukuhisa, Kenjiro

1981-01-01

The genetically significant dose (GSD), per Caput mean bone marrow dose (CMD), leukemia significant dose (LSD) and malignancy significant dose (MSD) from medical diagnostic X-ray examinations in Japan were estimated based on a 1979 nationwide survey of randomly sampled hospitals and clinics. The population risk estimates were carried out using the resultant values of GSD, LSD and MSD. In the risk estimates, the significant factors, namely, the relative child expectancy, the leukemia significant factor and the malignancy significant factor, for patients were assumed to be same as those of general population. The risk factors used were 185 x 10 -6 rad -1 for genetic risk of all generations, 20 x 10 -6 rad -1 for fatal leukemia and 165 x 10 -6 rad -1 for fatal malignant diseases, respectively. The resultant annual population doses per person were 15 mrad (0.15 mGy) for GSD, 107 mrad (1.07 mGy) for CMD, 86 mrad (0.86 mGy) for LSD and 43 mrad (0.43 mGy) for MSD, respectively. The present data other than the MSD were compared with the data in 1960, 1969 and 1974. For example, the GSD of 1979 was approximately same as that of 1974, although the annual number of examinations in 1979 increased by about 30 percent as compared with those of 1974. The population risks from X-ray diagnosis were estimated to be 260 persons per year for genetic risk of all generations, 192 person per year for fatal leukemic risk and 825 person per year for malignant risk, respectively, for the whole population in Japan, assuming that the X-ray diagnosis in 1979 will be performed continuously in the future. The average risks per one exposure for X-ray radiography were estimated using the weighted average of the significant factor and the organ or tissue dose with the number of radiographic exposures by age and by type of examination. The average risks per radiographic exposure were 176 x 10 -9 for genetic risk, 285 x 10 -9 for leukemic risk and 1.75 x 10 -6 for malignant risk respectively. (author)

MARKET RISK ESTIMATION IN (T+-TRANSACTIONS

Directory of Open Access Journals (Sweden)

Radik B. Begov

2016-01-01

Full Text Available Market risk analysis and estimation are presentedin T+ transactionsas they are used within the Moscow Exchange. There is a need to do so as a result of the cut-off of a new REPO product with Central Counterpartner (CCP. Here repurchase agreement goes through the National Clearing Center (NCC, the last being a bank and a clearing structure within the Moscow Exchange group.NCC actsas an intermediary (so called “Central Counterpartner” between trading participants.REPOs with CCP raisecontractor claims and commitments to the CCP which takes the risk of default on commitments from unfair contract side. The REPO with CCP cut-off made ready a technological platform to implement T+2 trades at the Moscow Exchange. As a result of it there appeared the possibility to enter security purchase/sell contracts partially collateralized. All these transactions (the REPO with CCP, T+ made it a must determining security market risks. The paper is aimed at presenting VaR-like risk estimates. The methods used are from the computer fi nance. Unusual TS rate of return indicator is proposed and applied to find optimal portfolios under the Markowitz approach and their VaRs (losses forecasts given the real “big” share price data and various horizons. Portfolio extreme rate and loss forecasting is our goal. To this end the forecasts are computed for three horizons (2, 5 and 10 days and for three significance levels.There were developed R-, Excel- and Bloomberg-basedsoftware tools as needed. The whole range of proposed computing steps and the tables with charts may be considered as candidates to be included in the future market risk standards.Paper results permit capital market participants to choose the correct (as to the required risk level common stocks.

Nonparametric estimation of benchmark doses in environmental risk assessment

Science.gov (United States)

Piegorsch, Walter W.; Xiong, Hui; Bhattacharya, Rabi N.; Lin, Lizhen

2013-01-01

Summary An important statistical objective in environmental risk analysis is estimation of minimum exposure levels, called benchmark doses (BMDs), that induce a pre-specified benchmark response in a dose-response experiment. In such settings, representations of the risk are traditionally based on a parametric dose-response model. It is a well-known concern, however, that if the chosen parametric form is misspecified, inaccurate and possibly unsafe low-dose inferences can result. We apply a nonparametric approach for calculating benchmark doses, based on an isotonic regression method for dose-response estimation with quantal-response data (Bhattacharya and Kong, 2007). We determine the large-sample properties of the estimator, develop bootstrap-based confidence limits on the BMDs, and explore the confidence limits’ small-sample properties via a short simulation study. An example from cancer risk assessment illustrates the calculations. PMID:23914133

Estimation of risks to humans following intake of plutonium

International Nuclear Information System (INIS)

Dolphin, G.W.

1979-01-01

The lung cancer in humans induced by plutonium intake usually starts in bronchial epithelium. The main types of lung cancer are epidermoid or squamous cell carcinoma, small cell anaplastic carcinoma, carcinoid types and bronchio-loalveolar cell carcinoma. The data on cancer in the patients given intravascular injections of Thorotrast are the only source of data from which risk estimates can be made for liver cancer. In the beagles injected with plutonium citrate, the only type of liver tumors observed in cholangiosarcoma, and if this were the case for humans, then the appropriate risk estimate is 3 times lower in human patients. Bone sarcoma and the cancer of the epithelial surfaces close to bones have been reported extensively in workers and patients exposed to radium-226 and radium-224. In the case of plutonium, it is assumed for the purpose of risk estimates that the cancer of the epithelial surfaces near bones does not occur. Plutonium passes through guts following ingestion or following the clearance of particles initially deposited in respiratory tracts. In the case of all long-lived radionuclides, lower large intestines are the region which receive the greatest dose from the activity passing through guts. It is assumed that plutonium accumulates in bone marrows through the action of macrophages engulfing the plutonium resorbed from bone surfaces. The main uncertainty in estimating the annual limit of intake probably lies in the metabolic and dosimetric models, and to a lesser extent, in the estimate of risk. (Yamashita, S.)

Comparison of prospective risk estimates for postoperative complications: human vs computer model.

Science.gov (United States)

Glasgow, Robert E; Hawn, Mary T; Hosokawa, Patrick W; Henderson, William G; Min, Sung-Joon; Richman, Joshua S; Tomeh, Majed G; Campbell, Darrell; Neumayer, Leigh A

2014-02-01

Surgical quality improvement tools such as NSQIP are limited in their ability to prospectively affect individual patient care by the retrospective audit and feedback nature of their design. We hypothesized that statistical models using patient preoperative characteristics could prospectively provide risk estimates of postoperative adverse events comparable to risk estimates provided by experienced surgeons, and could be useful for stratifying preoperative assessment of patient risk. This was a prospective observational cohort. Using previously developed models for 30-day postoperative mortality, overall morbidity, cardiac, thromboembolic, pulmonary, renal, and surgical site infection (SSI) complications, model and surgeon estimates of risk were compared with each other and with actual 30-day outcomes. The study cohort included 1,791 general surgery patients operated on between June 2010 and January 2012. Observed outcomes were mortality (0.2%), overall morbidity (8.2%), and pulmonary (1.3%), cardiac (0.3%), thromboembolism (0.2%), renal (0.4%), and SSI (3.8%) complications. Model and surgeon risk estimates showed significant correlation (p risk for overall morbidity to be low, the model-predicted risk and observed morbidity rates were 2.8% and 4.1%, respectively, compared with 10% and 18% in perceived high risk patients. Patients in the highest quartile of model-predicted risk accounted for 75% of observed mortality and 52% of morbidity. Across a broad range of general surgical operations, we confirmed that the model risk estimates are in fairly good agreement with risk estimates of experienced surgeons. Using these models prospectively can identify patients at high risk for morbidity and mortality, who could then be targeted for intervention to reduce postoperative complications. Published by Elsevier Inc.

FN-curves: preliminary estimation of severe accident risks after Fukushima

International Nuclear Information System (INIS)

Vasconcelos, Vanderley de; Soares, Wellington Antonio; Costa, Antonio Carlos Lopes da

2015-01-01

Doubts of whether the risks related to severe accidents in nuclear reactors are indeed very low were raised after the nuclear accident at Fukushima Daiichi in 2011. Risk estimations of severe accidents in nuclear power plants involve both probability and consequence assessment of such events. Among the ways to display risks, risk curves are tools that express the frequency of exceeding a certain magnitude of consequence. Societal risk is often represented graphically in a FN-curve, a type of risk curve, which displays the probability of having N or more fatalities per year, as a function of N, on a double logarithmic scale. The FN-curve, originally introduced for the assessment of the risks in the nuclear industry through the U.S.NRC Reactor Safety Study WASH-1400 (1975), is used in various countries to express and limit risks of hazardous activities. This first study estimated an expected rate of core damage equal to 5x10 -5 by reactor-year and suggested an upper bound of 3x10 -4 by reactor-year. A more recent report issued by Electric Power Research Institute - EPRI (2008) estimates a figure of the order of 2x10 -5 by reactor-year. The Fukushima nuclear accident apparently implies that the observed core damage frequency is higher than that predicted by these probabilistic safety assessments. Therefore, this paper presents a preliminary analyses of the FN-curves related to severe nuclear reactor accidents, taking into account a combination of available data of past accidents, probability modelling to estimate frequencies, and expert judgments. (author)

FN-curves: preliminary estimation of severe accident risks after Fukushima

Energy Technology Data Exchange (ETDEWEB)

Vasconcelos, Vanderley de; Soares, Wellington Antonio; Costa, Antonio Carlos Lopes da, E-mail: vasconv@cdtn.br, E-mail: soaresw@cdtn.br, E-mail: aclc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2015-07-01

Doubts of whether the risks related to severe accidents in nuclear reactors are indeed very low were raised after the nuclear accident at Fukushima Daiichi in 2011. Risk estimations of severe accidents in nuclear power plants involve both probability and consequence assessment of such events. Among the ways to display risks, risk curves are tools that express the frequency of exceeding a certain magnitude of consequence. Societal risk is often represented graphically in a FN-curve, a type of risk curve, which displays the probability of having N or more fatalities per year, as a function of N, on a double logarithmic scale. The FN-curve, originally introduced for the assessment of the risks in the nuclear industry through the U.S.NRC Reactor Safety Study WASH-1400 (1975), is used in various countries to express and limit risks of hazardous activities. This first study estimated an expected rate of core damage equal to 5x10{sup -5} by reactor-year and suggested an upper bound of 3x10{sup -4} by reactor-year. A more recent report issued by Electric Power Research Institute - EPRI (2008) estimates a figure of the order of 2x10{sup -5} by reactor-year. The Fukushima nuclear accident apparently implies that the observed core damage frequency is higher than that predicted by these probabilistic safety assessments. Therefore, this paper presents a preliminary analyses of the FN-curves related to severe nuclear reactor accidents, taking into account a combination of available data of past accidents, probability modelling to estimate frequencies, and expert judgments. (author)

Estimated drinking water fluoride exposure and risk of hip fracture: a cohort study.

Science.gov (United States)

Näsman, P; Ekstrand, J; Granath, F; Ekbom, A; Fored, C M

2013-11-01

The cariostatic benefit from water fluoridation is indisputable, but the knowledge of possible adverse effects on bone and fracture risk due to fluoride exposure is ambiguous. The association between long-term (chronic) drinking water fluoride exposure and hip fracture (ICD-7-9: '820' and ICD-10: 'S72.0-S72.2') was assessed in Sweden using nationwide registers. All individuals born in Sweden between January 1, 1900 and December 31, 1919, alive and living in their municipality of birth at the time of start of follow-up, were eligible for this study. Information on the study population (n = 473,277) was linked among the Swedish National In-Patient Register (IPR), the Swedish Cause of Death Register, and the Register of Population and Population Changes. Estimated individual drinking water fluoride exposure was stratified into 4 categories: very low, hip fracture. The risk estimates did not change in analyses restricted to only low-trauma osteoporotic hip fractures. Chronic fluoride exposure from drinking water does not seem to have any important effects on the risk of hip fracture, in the investigated exposure range.

Ecological risk estimation

International Nuclear Information System (INIS)

Bartell, S.M.; Gardner, R.H.; O'Neill, R.V.

1992-01-01

Ecological risk assessment, the process that evaluates the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more stressors, is being developed by the US EPA as a tool for decision making. This book presents one approach to risk assessment-that of applying laboratory toxicity data within an ecosystem model to predict the potential ecological consequences of toxic chemicals. Both Standard Water Column Model (SWACOM), using zooplankton and fish, and Monte Carlo simulations are discussed in detail, along with quantitative explanations for many responses. Simplifying assumptions are explicitly presented. The final chapter discusses strengths, weaknesses, and future directions of the approach. The book is appropriate for anyone who does or uses ecological risk assessment methodologies

Distribution of Estimated 10-Year Risk of Recurrent Vascular Events and Residual Risk in a Secondary Prevention Population

NARCIS (Netherlands)

Kaasenbrood, Lotte; Boekholdt, S. Matthijs; van der Graaf, Yolanda; Ray, Kausik K.; Peters, Ron J. G.; Kastelein, John J. P.; Amarenco, Pierre; LaRosa, John C.; Cramer, Maarten J. M.; Westerink, Jan; Kappelle, L. Jaap; de Borst, Gert J.; Visseren, Frank L. J.

2016-01-01

Among patients with clinically manifest vascular disease, the risk of recurrent vascular events is likely to vary. We assessed the distribution of estimated 10-year risk of recurrent vascular events in a secondary prevention population. We also estimated the potential risk reduction and residual

Distribution of Estimated 10-Year Risk of Recurrent Vascular Events and Residual Risk in a Secondary Prevention Population

NARCIS (Netherlands)

Kaasenbrood, Lotte; Boekholdt, S. Matthijs; Van Der Graaf, Yolanda; Ray, Kausik K.; Peters, Ron J G; Kastelein, John J P; Amarenco, Pierre; Larosa, John C.; Cramer, Maarten J M; Westerink, Jan; Kappelle, L. Jaap; De Borst, Gert J.; Visseren, Frank L J

2016-01-01

Background: Among patients with clinically manifest vascular disease, the risk of recurrent vascular events is likely to vary. We assessed the distribution of estimated 10-year risk of recurrent vascular events in a secondary prevention population. We also estimated the potential risk reduction and

Risk Consideration and Cost Estimation in Construction Projects Using Monte Carlo Simulation

Directory of Open Access Journals (Sweden)

Claudius A. Peleskei

2015-06-01

Full Text Available Construction projects usually involve high investments. It is, therefore, a risky adventure for companies as actual costs of construction projects nearly always exceed the planed scenario. This is due to the various risks and the large uncertainty existing within this industry. Determination and quantification of risks and their impact on project costs within the construction industry is described to be one of the most difficult areas. This paper analyses how the cost of construction projects can be estimated using Monte Carlo Simulation. It investigates if the different cost elements in a construction project follow a specific probability distribution. The research examines the effect of correlation between different project costs on the result of the Monte Carlo Simulation. The paper finds out that Monte Carlo Simulation can be a helpful tool for risk managers and can be used for cost estimation of construction projects. The research has shown that cost distributions are positively skewed and cost elements seem to have some interdependent relationships.

Estimating doses and risks associated with decontamination and decommissioning activities using the CRRIS

International Nuclear Information System (INIS)

Miller, C.W.; Sjoreen, A.L.; Cotter, S.J.

1986-01-01

The Computerized Radiological Risk Investigation System (CRRIS) is applicable to determining doses and risks from a variety of decontamination and decommissioning activities. For example, concentrations in air from resuspended radionuclides initially deposited on the ground surface and the concentrations of deposited radionuclides in various soil layers can be obtained. The CRRIS will estimate exposure to radon and its progeny in terms of working-level months, and will compute the resulting health risks. The CRRIS consists of seven integrated computer codes that stand alone or are run as a system to calculate environmental transport, doses, and risks. PRIMUS output provides other CRRIS codes the capability to handle radionuclide decay chains. ANEMOS and RETADD-II calculate atmospheric dispersion and deposition for local and regional distances, respectively. Multiple ANEMOS runs for sources within a small area are combined on a master grid by SUMIT. MLSOIL is used to estimate effective ground surface concentrations for dose computations. TERRA calculates food chain transport, and ANDROS calculates individual or population exposures, doses, and risks. Applications of the CRRIS to decontamination problems are discussed. 16 refs., 1 fig

Effective dose and cancer risk in PET/CT exams

International Nuclear Information System (INIS)

Pinto, Gabriella M.; Sa, Lidia Vasconcellos de

2013-01-01

Due to the use of radiopharmaceutical positron-emitting in PET exam and realization of tomography by x-ray transmission in CT examination, an increase of dose with hybrid PET/CT technology is expected. However, differences of doses have been reported in many countries for the same type of procedure. It is expected that the dose is an influent parameter to standardize the protocols of PET/CT. This study aimed to estimate the effective doses and absorbed in 65 patients submitted to oncological Protocol in a nuclear medicine clinic in Rio de Janeiro, considering the risk of induction of cancer from the scan. The CT exam-related doses were estimated with a simulator of PMMA and simulated on the lmPACT resistance, which for program effective dose, were considered the weight factors of the lCRP 103. The PET exam doses were estimated by multiplying the activity administered to the patient with the ICRP dose 80 factors. The radiological risk for cancer incidence were estimated according to the ICRP 103. The results showed that the effective dose from CT exam is responsible for 70% of the effective total in a PET/CT scan. values of effective dose for the PET/CT exam reached average values of up to 25 mSv leading to a risk of 2, 57 x 10 -4 . Considering that in staging of oncological diseases at least four tests are performed annually, the total risk comes to 1,03x 10 -3

A New Model for the Estimation of Breast Cancer Risk

National Research Council Canada - National Science Library

Giger, Maryellen Lissak

2001-01-01

... for use in estimating risk of breast cancer. The specific aims include 1. Creating a database of mammograms, along with tabulated clinical information of women at low risk and high risk for breast cancer; 2...

Estimation of enhanced cancer risk with 18FDG PET/CT investigations

International Nuclear Information System (INIS)

Kaushik, Aruna; Mishra, Anil K.; Sharma, Rajnish; Mondal, Anupam; Dwarakanath, B.S.

2014-01-01

18 F-Fluorodeoxyglucose ( 18 FDG) Positron Emission Tomography/Computed Tomography (PET/CT) investigation involves internal administration of 18 FDG and use of CT X-rays for the purpose of obtaining functional and anatomical information of a patient. However, the radiation exposure from undergoing PET/CT investigation may enhance the risk of cancer incidence as per the Linear-No-Threshold (LNT) model. The objective of the present study was to quantify the risk of cancer incidence associated with radiation exposure from 18 FDG PET/CT investigations. The organ doses from internally administered 18 FDG were estimated using OLINDA/EXM Code by performing dynamic PET scans in different regions of the body in a total of forty-nine patients. Organ doses from the CT component were calculated using the software CT-Expo. The associated cancer risk was calculated in terms of life time risk of cancer incidence resulting from a specified dose of ionizing radiation and was expressed in terms of Lifetime Attributable Risk (LAR). LAR values and the organ doses estimated for males and females were used to estimate the lifetime risk of cancer incidence from whole body 18 FDG PET/CT scan. Since from 18 FDG whole body PET/CT investigations, various tissues of the body receive substantially different doses, the site specific risk of cancer incidence was estimated and summed to obtain the total risk. This was compared with the baseline lifetime risk of cancer incidence in Indian population. LAR of cancer incidence was observed to be relatively higher in females as compared to males. The risk estimates ranged from 0.36% to 0.49% for a 20 year old male and 0.58% to 0.79% for a 20 year old female and were observed to be higher in younger ages and decreased with age. 18 FDG whole body PET/CT investigation was observed to be associated with non-negligible radiation risk as compared to the risks associated with other diagnostic modalities. (author)

Estimation of population dose and risk to holding assistants from veterinary X-ray examination in Japan

International Nuclear Information System (INIS)

Hashizume, Tadashi; Suganuma, Tunenori; Shida, Takuo

1989-01-01

For the estimation of the population doses and risks of stochastic effects to assistants who hold animals during veterinary X-ray examination, a random survey of hospitals and clinics was carried out concerning age distribution of such assistants by groups of facilities. The average organ and tissue dose per examination was evaluated from the experimental data using mean technical factors such as X-ray tube voltage, tube current and field size based on the results of a nationwide survey. The population doses to the assistants were calculated to be about 14 nSv per person per year for the genetically significant dose, 3.5 nSv per person per year for per caput mean marrow dose, 3.3 nSv for the leukemia significant dose and 4.5 nSv for the malignant significant dose, respectively. The total risk of stochastic effects to the Japanese population from holding assistants was estimated using population data and it was estimated to be less than one person per year, but the cancer risks to a number of the assistants were estimated to be more than 4 x 10 -5 . (author)

Reconstruction of financial networks for robust estimation of systemic risk

Science.gov (United States)

Mastromatteo, Iacopo; Zarinelli, Elia; Marsili, Matteo

2012-03-01

In this paper we estimate the propagation of liquidity shocks through interbank markets when the information about the underlying credit network is incomplete. We show that techniques such as maximum entropy currently used to reconstruct credit networks severely underestimate the risk of contagion by assuming a trivial (fully connected) topology, a type of network structure which can be very different from the one empirically observed. We propose an efficient message-passing algorithm to explore the space of possible network structures and show that a correct estimation of the network degree of connectedness leads to more reliable estimations for systemic risk. Such an algorithm is also able to produce maximally fragile structures, providing a practical upper bound for the risk of contagion when the actual network structure is unknown. We test our algorithm on ensembles of synthetic data encoding some features of real financial networks (sparsity and heterogeneity), finding that more accurate estimations of risk can be achieved. Finally we find that this algorithm can be used to control the amount of information that regulators need to require from banks in order to sufficiently constrain the reconstruction of financial networks.

Reconstruction of financial networks for robust estimation of systemic risk

International Nuclear Information System (INIS)

Mastromatteo, Iacopo; Zarinelli, Elia; Marsili, Matteo

2012-01-01

In this paper we estimate the propagation of liquidity shocks through interbank markets when the information about the underlying credit network is incomplete. We show that techniques such as maximum entropy currently used to reconstruct credit networks severely underestimate the risk of contagion by assuming a trivial (fully connected) topology, a type of network structure which can be very different from the one empirically observed. We propose an efficient message-passing algorithm to explore the space of possible network structures and show that a correct estimation of the network degree of connectedness leads to more reliable estimations for systemic risk. Such an algorithm is also able to produce maximally fragile structures, providing a practical upper bound for the risk of contagion when the actual network structure is unknown. We test our algorithm on ensembles of synthetic data encoding some features of real financial networks (sparsity and heterogeneity), finding that more accurate estimations of risk can be achieved. Finally we find that this algorithm can be used to control the amount of information that regulators need to require from banks in order to sufficiently constrain the reconstruction of financial networks

An Estimation of Risk Impact of Anticipated Transients without Scram for a KSNP

Energy Technology Data Exchange (ETDEWEB)

Han, Seok Jung; Yang Joon Eon

2006-07-15

Anticipated transient without scram (ATWS) event is an accident sequence with large risk impact, while it is a beyond design basis accident (BDBA). We have estimated a risk due to an ATWS accident sequence for the KSNP in consideration of the recent accident analysis results. The SECY-83-293's model for the CE type plants has been used in a risk estimation of ATWS. A risk estimation due to an ATWS for the KSNP has been performed in consideration of the recent ATWS accident analysis results and plant information. We reviewed influence factors in the SECY-83-293's model, these factors have been re-estimated by using current information and PSA results for a KSNP. A risk due to an ATWS has been estimated as 3.6E-6/yr of CDF by using domestic aspect and recent KSNP information. A sensitivity study for the UET variation has been performed. As the results of the sensitivity analysis, the overall risk spectrum by the UET variation is bounded between 7.80E-7/yr to 8.00E-6/yr of CDF. As the result of the current study, the risk due to an ATWS accident sequence has been identified as a considerable impact on the entire risk of a KSNP, so the risk estimation of that plant should be upgraded by considering the recent information like the ATWS accident analysis results. Finally, we expect that this study can become a basis for the entire risk estimation of the referred plant.

Estimation of extreme risk regions under multivariate regular variation

NARCIS (Netherlands)

Cai, J.; Einmahl, J.H.J.; de Haan, L.F.M.

2011-01-01

When considering d possibly dependent random variables, one is often interested in extreme risk regions, with very small probability p. We consider risk regions of the form {z ∈ Rd : f (z) ≤ β}, where f is the joint density and β a small number. Estimation of such an extreme risk region is difficult

ESTIMATING RISK ON THE CAPITAL MARKET WITH VaR METHOD

Directory of Open Access Journals (Sweden)

Sinisa Bogdan

2015-06-01

Full Text Available The two basic questions that every investor tries to answer before investment are questions about predicting return and risk. Risk and return are generally considered two positively correlated sizes, during the growth of risk it is expected increase of return to compensate the higher risk. The quantification of risk in the capital market represents the current topic since occurrence of securities. Together with estimated future returns it represents starting point of any investment. In this study it is described the history of the emergence of VaR methods, usefulness in assessing the risks of financial assets. Three main Value at Risk (VaR methodologies are decribed and explained in detail: historical method, parametric method and Monte Carlo method. After the theoretical review of VaR methods it is estimated risk of liquid stocks and portfolio from the Croatian capital market with historical and parametric VaR method, after which the results were compared and explained.

Estimating effectiveness in HIV prevention trials with a Bayesian hierarchical compound Poisson frailty model

Science.gov (United States)

Coley, Rebecca Yates; Browna, Elizabeth R.

2016-01-01

Inconsistent results in recent HIV prevention trials of pre-exposure prophylactic interventions may be due to heterogeneity in risk among study participants. Intervention effectiveness is most commonly estimated with the Cox model, which compares event times between populations. When heterogeneity is present, this population-level measure underestimates intervention effectiveness for individuals who are at risk. We propose a likelihood-based Bayesian hierarchical model that estimates the individual-level effectiveness of candidate interventions by accounting for heterogeneity in risk with a compound Poisson-distributed frailty term. This model reflects the mechanisms of HIV risk and allows that some participants are not exposed to HIV and, therefore, have no risk of seroconversion during the study. We assess model performance via simulation and apply the model to data from an HIV prevention trial. PMID:26869051

Estimation of value at risk and conditional value at risk using normal mixture distributions model

Science.gov (United States)

Kamaruzzaman, Zetty Ain; Isa, Zaidi

2013-04-01

Normal mixture distributions model has been successfully applied in financial time series analysis. In this paper, we estimate the return distribution, value at risk (VaR) and conditional value at risk (CVaR) for monthly and weekly rates of returns for FTSE Bursa Malaysia Kuala Lumpur Composite Index (FBMKLCI) from July 1990 until July 2010 using the two component univariate normal mixture distributions model. First, we present the application of normal mixture distributions model in empirical finance where we fit our real data. Second, we present the application of normal mixture distributions model in risk analysis where we apply the normal mixture distributions model to evaluate the value at risk (VaR) and conditional value at risk (CVaR) with model validation for both risk measures. The empirical results provide evidence that using the two components normal mixture distributions model can fit the data well and can perform better in estimating value at risk (VaR) and conditional value at risk (CVaR) where it can capture the stylized facts of non-normality and leptokurtosis in returns distribution.

Radiation quality and effective dose equivalent of alpha particles from radon decay products indoors: uncertainties in risk estimation

Energy Technology Data Exchange (ETDEWEB)

Al-Affan, I.A. (Velindre Hospital, Whitchurch, Cardiff (United Kingdom))

1994-01-01

In order to make a better estimate of cancer risk due to radon the radiation quality of alpha particles emitted from the element and its daughters has been re-assessed. In particular, uncertainties in all components involved in the calculations of the effective dose E, have been investigated. This has been done in the light of the recent draft report of the ICRU on quantities and units for use in radiation protection (Allisy et al (1991) ICRU NEWS 2). On the assumption of an indoor radon concentration of 30 Bq.m[sup -3], microdose spectra have been calculated for alpha particles hitting lung cells at different depths. Then the mean quality factor Q-bar in the lung, dose equivalent H[sub T] to the lung and the effective dose have been calculated. A comparison between lung cancer risk from radon and that arising from diagnostic X rays to the chest is made. A suggestion to make the lung weighting factor w[sub T] a function of the fraction of lung cells hit is discussed. (Author).

Estimate of the economy-wide financial risk associated with a serious nuclear reactor accident

International Nuclear Information System (INIS)

Heising, C.D.; George, V.P.

1985-01-01

Since the accident at Three Mile Island, considerable attention has focused on the financial risks associated with nuclear reactor accidents. Previous studies have calculated the plant-specific financial risk due to primarily off-site consequences, including most probabilistic risk assessments (PRAs) beginning first with the Reactor Safety Study. Previous studies, however, have not studied the possible economy-wide costs of a severe reactor accident due to such considerations as adverse public opinion, enhanced concern in the financial community, and, particularly, regulatory constraints placed on the industry subsequent to an accident. These considerations could lead to a spectrum of scenarios, including partial or complete nuclear moratoria, which may have far reaching economy-wide effects. It is the purpose of this study to provide an estimate of these effects, and to compare these estimates with the plant-specific financial risks calculated earlier by others. First, a model is presented for including the impact of various regulatory response options on the nuclear industry, followed by a discussion of how the economy-wide costs associated with these options may be calculated. Then, results of series of calculations are presented, and finally, conclusions are given

Final report on the project research 'stochastic effects of irradiation and risk estimation'

International Nuclear Information System (INIS)

1989-03-01

The title project research was carried out through 1983-1987, by three groups for the studies of radiation carcinogenesis, human genetic effects, and radiotoxicology. 8 reports by the first group, 3 by the second, and 6 by the third group are collected in this issue. The contents are as follows. Serial sacrifice study on tumorigenesis in male C57BL/6J mice exposed to gamma-ray or fast neutron radiation; Influence of biological variables on radiation carcinogenesis; Studies on radiation-induced thymic lymphomagenesis; Modifying factors of radiation induced myeloid leukemia of C3H/He mouse; Cell kinetic studies on radiation induced leukemogenesis; Cytogenetical studies on the mechanism of radiation induced neoplasmas; Molecular biological study on genetic stability of the genome; Protein factors regulating proliferation and differentiation of normal and neoplastic cells; Studies on dose-radiation relationships for induction of chromosome abberations in stem-spermatogonia of three crab-eating monkey after low and high dose rate γ-irradiation; Risk estimation of radiation mutagenesis in man by using cultured mammalian cells; Effects of ionizing radiation on male germ cells of crabeating monkey; Movement and metabolism of radioactive particles in the respiratory tract; Studies on dosimetry for internally deposited alpha-emitters; Comparative toxicological studies on the effects of internal exposures; Studies on treatment of alpha-radioactive wastes; Methodological studies on the inhalation of radioactive aerosols; Removal of transuranic elements by DTPA. (A. Y.)

The economic costs of radiation-induced health effects: Estimation and simulation

International Nuclear Information System (INIS)

Nieves, L.A.; Tawil, J.J.

1988-08-01

This effort improves the quantitative information available for use in evaluating actions that alter health risks due to population exposure to ionizing radiation. To project the potential future costs of changes in health effects risks, Pacific Northwest Laboratory (PNL) constructed a probabilistic computer model, Health Effects Costs Model (HECOM), which utilizes the health effect incidence estimates from accident consequences models to calculate the discounted sum of the economic costs associated with population exposure to ionizing radiation. Application of HECOM to value-impact and environmental impact analyses should greatly increase the quality of the information available for regulatory decision making. Three major types of health effects present risks for any population sustaining a significant radiation exposure: acute radiation injuries (and fatalities), latent cancers, and impairments due to genetic effects. The literature pertaining to both incidence and treatment of these health effects was reviewed by PNL and provided the basis for developing economic cost estimates. The economic costs of health effects estimated by HECOM represent both the value of resources consumed in diagnosing, treating, and caring for the patient and the value of goods not produced because of illness or premature death due to the health effect. Additional costs to society, such as pain and suffering, are not included in the PNL economic cost measures since they do not divert resources from other uses, are difficult to quantify, and do not have a value observable in the marketplace. 83 refs., 3 figs., 19 tabs

The economic costs of radiation-induced health effects: Estimation and simulation

Energy Technology Data Exchange (ETDEWEB)

Nieves, L.A.; Tawil, J.J.

1988-08-01

This effort improves the quantitative information available for use in evaluating actions that alter health risks due to population exposure to ionizing radiation. To project the potential future costs of changes in health effects risks, Pacific Northwest Laboratory (PNL) constructed a probabilistic computer model, Health Effects Costs Model (HECOM), which utilizes the health effect incidence estimates from accident consequences models to calculate the discounted sum of the economic costs associated with population exposure to ionizing radiation. Application of HECOM to value-impact and environmental impact analyses should greatly increase the quality of the information available for regulatory decision making. Three major types of health effects present risks for any population sustaining a significant radiation exposure: acute radiation injuries (and fatalities), latent cancers, and impairments due to genetic effects. The literature pertaining to both incidence and treatment of these health effects was reviewed by PNL and provided the basis for developing economic cost estimates. The economic costs of health effects estimated by HECOM represent both the value of resources consumed in diagnosing, treating, and caring for the patient and the value of goods not produced because of illness or premature death due to the health effect. Additional costs to society, such as pain and suffering, are not included in the PNL economic cost measures since they do not divert resources from other uses, are difficult to quantify, and do not have a value observable in the marketplace. 83 refs., 3 figs., 19 tabs.

A practical approach to risk-benefit estimation in pediatric drug research.

Science.gov (United States)

Koren, Gideon

2015-02-01

One of the most difficult challenges in pediatric drug research is in exposing children to risk, often without a balanced chance of benefits. While the concept of risk is similar in adult research, the adult patient can decide for himself/herself on an acceptable level of risk, whereas children have to accept the decisions of their guardians. This paper attempts to put the complexities of estimating risk in pediatric drug research into their practical perspective, and to familiarize the reader with the way such processes are conducted in different parts of the world. Although there are regional differences, all authorities typically quantify risks of pediatric research in general, and drug research in particular, in three levels: those experienced in day-to-day life; risks slightly above this 'baseline' risk; and risks substantially above 'baseline risk'. Proportionally, the diligence of the ethics process depends on these levels, as well as on the potential benefits (or lack of) to the child involved in the research. Importantly, risk is context dependent, and a particular intervention may be effective or safe in one setting but not in another, based on local experience, staffing levels, and similar variabilities.

The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma

DEFF Research Database (Denmark)

Maraldo, M V; Jørgensen, M; Brodin, N P

2014-01-01

BACKGROUND: The use of radiotherapy (RT) is debated for pediatric patients with Hodgkin lymphoma (HL) due to the late effects of treatment. Radiation doses to the thyroid, heart, lungs, and breasts are compared with the extensive mantle field (MF), Involved Field RT(IFRT), Modified IFRT (m......IFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I......–II classical HL patients lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow...

Prognostic risk estimates of patients with multiple sclerosis and their physicians: comparison to an online analytical risk counseling tool.

Directory of Open Access Journals (Sweden)

Christoph Heesen

Full Text Available BACKGROUND: Prognostic counseling in multiple sclerosis (MS is difficult because of the high variability of disease progression. Simultaneously, patients and physicians are increasingly confronted with making treatment decisions at an early stage, which requires taking individual prognoses into account to strike a good balance between benefits and harms of treatments. It is therefore important to understand how patients and physicians estimate prognostic risk, and whether and how these estimates can be improved. An online analytical processing (OLAP tool based on pooled data from placebo cohorts of clinical trials offers short-term prognostic estimates that can be used for individual risk counseling. OBJECTIVE: The aim of this study was to clarify if personalized prognostic information as presented by the OLAP tool is considered useful and meaningful by patients. Furthermore, we used the OLAP tool to evaluate patients' and physicians' risk estimates. Within this evaluation process we assessed short-time prognostic risk estimates of patients with MS (final n = 110 and their physicians (n = 6 and compared them with the estimates of OLAP. RESULTS: Patients rated the OLAP tool as understandable and acceptable, but to be only of moderate interest. It turned out that patients, physicians, and the OLAP tool ranked patients similarly regarding their risk of disease progression. Both patients' and physicians' estimates correlated most strongly with those disease covariates that the OLAP tool's estimates also correlated with most strongly. Exposure to the OLAP tool did not change patients' risk estimates. CONCLUSION: While the OLAP tool was rated understandable and acceptable, it was only of modest interest and did not change patients' prognostic estimates. The results suggest, however, that patients had some idea regarding their prognosis and which factors were most important in this regard. Future work with OLAP should assess long-term prognostic

Prognostic risk estimates of patients with multiple sclerosis and their physicians: comparison to an online analytical risk counseling tool.

Science.gov (United States)

Heesen, Christoph; Gaissmaier, Wolfgang; Nguyen, Franziska; Stellmann, Jan-Patrick; Kasper, Jürgen; Köpke, Sascha; Lederer, Christian; Neuhaus, Anneke; Daumer, Martin

2013-01-01

Prognostic counseling in multiple sclerosis (MS) is difficult because of the high variability of disease progression. Simultaneously, patients and physicians are increasingly confronted with making treatment decisions at an early stage, which requires taking individual prognoses into account to strike a good balance between benefits and harms of treatments. It is therefore important to understand how patients and physicians estimate prognostic risk, and whether and how these estimates can be improved. An online analytical processing (OLAP) tool based on pooled data from placebo cohorts of clinical trials offers short-term prognostic estimates that can be used for individual risk counseling. The aim of this study was to clarify if personalized prognostic information as presented by the OLAP tool is considered useful and meaningful by patients. Furthermore, we used the OLAP tool to evaluate patients' and physicians' risk estimates. Within this evaluation process we assessed short-time prognostic risk estimates of patients with MS (final n = 110) and their physicians (n = 6) and compared them with the estimates of OLAP. Patients rated the OLAP tool as understandable and acceptable, but to be only of moderate interest. It turned out that patients, physicians, and the OLAP tool ranked patients similarly regarding their risk of disease progression. Both patients' and physicians' estimates correlated most strongly with those disease covariates that the OLAP tool's estimates also correlated with most strongly. Exposure to the OLAP tool did not change patients' risk estimates. While the OLAP tool was rated understandable and acceptable, it was only of modest interest and did not change patients' prognostic estimates. The results suggest, however, that patients had some idea regarding their prognosis and which factors were most important in this regard. Future work with OLAP should assess long-term prognostic estimates and clarify its usefulness for patients and physicians

Impact of a financial risk-sharing scheme on budget-impact estimations: a game-theoretic approach.

Science.gov (United States)

Gavious, Arieh; Greenberg, Dan; Hammerman, Ariel; Segev, Ella

2014-06-01

As part of the process of updating the National List of Health Services in Israel, health plans (the 'payers') and manufacturers each provide estimates on the expected number of patients that will utilize a new drug. Currently, payers face major financial consequences when actual utilization is higher than the allocated budget. We suggest a risk-sharing model between the two stakeholders; if the actual number of patients exceeds the manufacturer's prediction, the manufacturer will reimburse the payers by a rebate rate of α from the deficit. In case of under-utilization, payers will refund the government at a rate of γ from the surplus budget. Our study objective was to identify the optimal early estimations of both 'players' prior to and after implementation of the risk-sharing scheme. Using a game-theoretic approach, in which both players' statements are considered simultaneously, we examined the impact of risk-sharing within a given range of rebate proportions, on players' early budget estimations. When increasing manufacturer's rebate α to be over 50 %, then manufacturers will announce a larger number, and health plans will announce a lower number of patients than they would without risk sharing, thus substantially decreasing the gap between their estimates. Increasing γ changes players' estimates only slightly. In reaction to applying a substantial risk-sharing rebate α on the manufacturer, both players are expected to adjust their budget estimates toward an optimal equilibrium. Increasing α is a better vehicle for reaching the desired equilibrium rather than increasing γ, as the manufacturer's rebate α substantially influences both players, whereas γ has little effect on the players behavior.

Value-at-Risk analysis using ARMAX GARCHX approach for estimating risk of banking subsector stock return’s

Science.gov (United States)

Dewi Ratih, Iis; Sutijo Supri Ulama, Brodjol; Prastuti, Mike

2018-03-01

Value at Risk (VaR) is one of the statistical methods used to measure market risk by estimating the worst losses in a given time period and level of confidence. The accuracy of this measuring tool is very important in determining the amount of capital that must be provided by the company to cope with possible losses. Because there is a greater losses to be faced with a certain degree of probability by the greater risk. Based on this, VaR calculation analysis is of particular concern to researchers and practitioners of the stock market to be developed, thus getting more accurate measurement estimates. In this research, risk analysis of stocks in four banking sub-sector, Bank Rakyat Indonesia, Bank Mandiri, Bank Central Asia and Bank Negara Indonesia will be done. Stock returns are expected to be influenced by exogenous variables, namely ICI and exchange rate. Therefore, in this research, stock risk estimation are done by using VaR ARMAX-GARCHX method. Calculating the VaR value with the ARMAX-GARCHX approach using window 500 gives more accurate results. Overall, Bank Central Asia is the only bank had the estimated maximum loss in the 5% quantile.

Jumps and Betas: A New Framework for Disentangling and Estimating Systematic Risks

DEFF Research Database (Denmark)

Todorov, Viktor; Bollerslev, Tim

market portfolio, we find the estimated diffusive and jump betas with respect to the market to be quite dif- ferent for many of the stocks. Our findings have direct and important implications for empirical asset pricing finance and practical portfolio and risk management decisions.......We provide a new theoretical framework for disentangling and estimating sensitivity towards systematic diffusive and jump risks in the context of factor pricing models. Our estimates of the sensitivities towards systematic risks, or betas, are based on the notion of increasingly finer sampled...

The estimation of risk-premium implicit in oil prices

International Nuclear Information System (INIS)

Luis, J.B.

2001-01-01

The futures price can be seen as the sum of the expected value of the underlying asset price and a risk-premium. In order to disentangle these two components of the futures price, one can try to model the relationship between spot and futures prices, in order to obtain a closed expression for the risk-premium, or to use information from spot and option prices to estimate risk-aversion functions. Given the high volatility of the ratios between futures and spot prices, we opted for the latter, estimating risk-neutral and subjective probability density functions, respectively, from observed option and spot prices. looking at the prices of Brent and West Texas Intermediate light/sweet crude oil options, the obtained evidence suggests that risk-aversion is typically very low for levels near the futures prices. However, due to price volatility and, consequently, to the tails of distribution, the risk-aversion functions are badly behaved in extreme prices and futures prices do not anticipate sharp movements in oil spot prices. Therefore, futures oil prices seem to be useful in forecasting spot prices only when moderate price changes occur. (author)

Estimation of the standardized risk difference and ratio in a competing risks framework: application to injection drug use and progression to AIDS after initiation of antiretroviral therapy.

Science.gov (United States)

Cole, Stephen R; Lau, Bryan; Eron, Joseph J; Brookhart, M Alan; Kitahata, Mari M; Martin, Jeffrey N; Mathews, William C; Mugavero, Michael J

2015-02-15

There are few published examples of absolute risk estimated from epidemiologic data subject to censoring and competing risks with adjustment for multiple confounders. We present an example estimating the effect of injection drug use on 6-year risk of acquired immunodeficiency syndrome (AIDS) after initiation of combination antiretroviral therapy between 1998 and 2012 in an 8-site US cohort study with death before AIDS as a competing risk. We estimate the risk standardized to the total study sample by combining inverse probability weights with the cumulative incidence function; estimates of precision are obtained by bootstrap. In 7,182 patients (83% male, 33% African American, median age of 38 years), we observed 6-year standardized AIDS risks of 16.75% among 1,143 injection drug users and 12.08% among 6,039 nonusers, yielding a standardized risk difference of 4.68 (95% confidence interval: 1.27, 8.08) and a standardized risk ratio of 1.39 (95% confidence interval: 1.12, 1.72). Results may be sensitive to the assumptions of exposure-version irrelevance, no measurement bias, and no unmeasured confounding. These limitations suggest that results be replicated with refined measurements of injection drug use. Nevertheless, estimating the standardized risk difference and ratio is straightforward, and injection drug use appears to increase the risk of AIDS. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[Survival analysis with competing risks: estimating failure probability].

Science.gov (United States)

Llorca, Javier; Delgado-Rodríguez, Miguel

2004-01-01

To show the impact of competing risks of death on survival analysis. We provide an example of survival time without chronic rejection after heart transplantation, where death before rejection acts as a competing risk. Using a computer simulation, we compare the Kaplan-Meier estimator and the multiple decrement model. The Kaplan-Meier method overestimated the probability of rejection. Next, we illustrate the use of the multiple decrement model to analyze secondary end points (in our example: death after rejection). Finally, we discuss Kaplan-Meier assumptions and why they fail in the presence of competing risks. Survival analysis should be adjusted for competing risks of death to avoid overestimation of the risk of rejection produced with the Kaplan-Meier method.

Soil-ecological risks for soil degradation estimation

Science.gov (United States)

Trifonova, Tatiana; Shirkin, Leonid; Kust, German; Andreeva, Olga

2016-04-01

Soil degradation includes the processes of soil properties and quality worsening, primarily from the point of view of their productivity and decrease of ecosystem services quality. Complete soil cover destruction and/or functioning termination of soil forms of organic life are considered as extreme stages of soil degradation, and for the fragile ecosystems they are normally considered in the network of their desertification, land degradation and droughts /DLDD/ concept. Block-model of ecotoxic effects, generating soil and ecosystem degradation, has been developed as a result of the long-term field and laboratory research of sod-podzol soils, contaminated with waste, containing heavy metals. The model highlights soil degradation mechanisms, caused by direct and indirect impact of ecotoxicants on "phytocenosis- soil" system and their combination, frequently causing synergistic effect. The sequence of occurring changes here can be formalized as a theory of change (succession of interrelated events). Several stages are distinguished here - from heavy metals leaching (releasing) in waste and their migration downward the soil profile to phytoproductivity decrease and certain phytocenosis composition changes. Phytoproductivity decrease leads to the reduction of cellulose content introduced into the soil. The described feedback mechanism acts as a factor of sod-podzolic soil self-purification and stability. It has been shown, that using phytomass productivity index, integrally reflecting the worsening of soil properties complex, it is possible to solve the problems dealing with the dose-reflecting reactions creation and determination of critical levels of load for phytocenosis and corresponding soil-ecological risks. Soil-ecological risk in "phytocenosis- soil" system means probable negative changes and the loss of some ecosystem functions during the transformation process of dead organic substance energy for the new biomass composition. Soil-ecological risks estimation is

Estimation of Radiological Terrorism Risk by Administrative Districts

Energy Technology Data Exchange (ETDEWEB)

Kim, Suk Hoon; Kim, Ju Youl [Seoul National Univ., Seoul (Korea, Republic of); Yoo, Ho Sik [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

2008-10-15

Since the 9/11 attack in USA, the threat of terrorism across the world has dramatically increased. Accordingly, estimating terrorism risk has become an essential part of catastrophe risk strategies throughout the world. There are many forms of terrorism. Recently, the prospect of the radiological terrorist attack using the radioactive material is considered as one of the most serious threats. The aim of this paper is to assess the radiological terrorism risk by administrative districts based on the parameters that imply threat, vulnerability, and consequences of terrorist attacks.

Estimation of Radiological Terrorism Risk by Administrative Districts

International Nuclear Information System (INIS)

Kim, Suk Hoon; Kim, Ju Youl; Yoo, Ho Sik

2008-01-01

Since the 9/11 attack in USA, the threat of terrorism across the world has dramatically increased. Accordingly, estimating terrorism risk has become an essential part of catastrophe risk strategies throughout the world. There are many forms of terrorism. Recently, the prospect of the radiological terrorist attack using the radioactive material is considered as one of the most serious threats. The aim of this paper is to assess the radiological terrorism risk by administrative districts based on the parameters that imply threat, vulnerability, and consequences of terrorist attacks

Estimated risks and optimistic self-perception of breast cancer risk in Korean women.

Science.gov (United States)

Chung, ChaeWeon; Lee, Suk Jeong

2013-11-01

To determine women's perceived personal and comparative risks of breast cancer, and to examine the relationships with risk factors. Despite the increasing incidence of breast cancer in younger women and the availability of screening, women's health behaviors have not advanced accordingly. A cross-sectional survey design utilized a convenience sample of 222 women in their 30s and 40s recruited from community settings in Seoul. Self-administered questionnaire data were analyzed by descriptive statistics, the chi-squared test, and ANOVA. Risk perception levels differed significantly by breast cancer risk factors. Half of the women were optimistic about their breast cancer risk, while perceived personal risk did not reflect women's own risk factors and comparative risk differed only by the practice of clinical breast exam. Women's knowledge and awareness of their breast cancer risk factors need to be improved for appropriate risk perception and health behaviors, and accurate risk estimation could be utilized to educate them in clinical settings. © 2013.

Adult head CT scans: the uncertainties of effective dose estimates

International Nuclear Information System (INIS)

Gregory, Kent J.; Bibbo, Giovanni; Pattison, John E.

2008-01-01

Full Text: CT scanning is a high dose imaging modality. Effective dose estimates from CT scans can provide important information to patients and medical professionals. For example, medical practitioners can use the dose to estimate the risk to the patient, and judge whether this risk is outweighed by the benefits of the CT examination, while radiographers can gauge the effect of different scanning protocols on the patient effective dose, and take this into consideration when establishing routine scan settings. Dose estimates also form an important part of epidemiological studies examining the health effects of medical radiation exposures on the wider population. Medical physicists have been devoting significant effort towards estimating patient radiation doses from diagnostic CT scans for some years. The question arises: How accurate are these effective dose estimates? The need for a greater understanding and improvement of the uncertainties in CT dose estimates is now gaining recognition as an important issue (BEIR VII 2006). This study is an attempt to analyse and quantify the uncertainty components relating to effective dose estimates from adult head CT examinations that are calculated with four commonly used methods. The dose estimation methods analysed are the Nagel method, the ImpaCT method, the Wellhoefer method and the Dose-Length Product (DLP) method. The analysis of the uncertainties was performed in accordance with the International Standards Organisation's Guide to the Expression of Uncertainty in Measurement as discussed in Gregory et al (Australas. Phys. Eng. Sci. Med., 28: 131-139, 2005). The uncertainty components vary, depending on the method used to derive the effective dose estimate. Uncertainty components in this study include the statistical and other errors from Monte Carlo simulations, uncertainties in the CT settings and positions of patients in the CT gantry, calibration errors from pencil ionization chambers, the variations in the organ

Competing risk bias was common in Kaplan-Meier risk estimates published in prominent medical journals.

Science.gov (United States)

van Walraven, Carl; McAlister, Finlay A

2016-01-01

Risk estimates from Kaplan-Meier curves are well known to medical researchers, reviewers, and editors. In this study, we determined the proportion of Kaplan-Meier analyses published in prominent medical journals that are potentially biased because of competing events ("competing risk bias"). We randomly selected 100 studies that had at least one Kaplan-Meier analysis and were recently published in prominent medical journals. Susceptibility to competing risk bias was determined by examining the outcome and potential competing events. In susceptible studies, bias was quantified using a previously validated prediction model when the number of outcomes and competing events were given. Forty-six studies (46%) contained Kaplan-Meier analyses susceptible to competing risk bias. Sixteen studies (34.8%) susceptible to competing risk cited the number of outcomes and competing events; in six of these studies (6/16, 37.5%), the outcome risk from the Kaplan-Meier estimate (relative to the true risk) was biased upward by 10% or more. Almost half of Kaplan-Meier analyses published in medical journals are susceptible to competing risk bias and may overestimate event risk. This bias was found to be quantitatively important in a third of such studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Stochastic evaluation of tsunami inundation and quantitative estimating tsunami risk

International Nuclear Information System (INIS)

Fukutani, Yo; Anawat, Suppasri; Abe, Yoshi; Imamura, Fumihiko

2014-01-01

We performed a stochastic evaluation of tsunami inundation by using results of stochastic tsunami hazard assessment at the Soma port in the Tohoku coastal area. Eleven fault zones along the Japan trench were selected as earthquake faults generating tsunamis. The results show that estimated inundation area of return period about 1200 years had good agreement with that in the 2011 Tohoku earthquake. In addition, we evaluated quantitatively tsunami risk for four types of building; a reinforced concrete, a steel, a brick and a wood at the Soma port by combining the results of inundation assessment and tsunami fragility assessment. The results of quantitative estimating risk would reflect properly vulnerability of the buildings, that the wood building has high risk and the reinforced concrete building has low risk. (author)

Estimating Worker Risk Levels Using Accident/Incident Data

Energy Technology Data Exchange (ETDEWEB)

Kenoyer, Judson L.; Stenner, Robert D.; Andrews, William B.; Scherpelz, Robert I.; Aaberg, Rosanne L.

2000-09-26

The purpose of the work described in this report was to identify methods that are currently being used in the Department of Energy (DOE) complex to identify and control hazards/risks in the workplace, evaluate them in terms of their effectiveness in reducing risk to the workers, and to develop a preliminary method that could be used to predict the relative risks to workers performing proposed tasks using some of the current methodology. This report describes some of the performance indicators (i.e., safety metrics) that are currently being used to track relative levels of workplace safety in the DOE complex, how these fit into an Integrated Safety Management (ISM) system, some strengths and weaknesses of using a statistically based set of indicators, and methods to evaluate them. Also discussed are methods used to reduce risk to the workers and some of the techniques that appear to be working in the process of establishing a condition of continuous improvement. The results of these methods will be used in future work involved with the determination of modifying factors for a more complex model. The preliminary method to predict the relative risk level to workers during an extended future time period is based on a currently used performance indicator that uses several factors tracked in the CAIRS. The relative risks for workers in a sample (but real) facility on the Hanford site are estimated for a time period of twenty years and are based on workforce predictions. This is the first step in developing a more complex model that will incorporate other modifying factors related to the workers, work environment and status of the ISM system to adjust the preliminary prediction.

A Comparison Study on the Integrated Risk Estimation for Various Power Systems

International Nuclear Information System (INIS)

Kim, Tae Woon; Ha, J. J.; Kim, S. H.; Jeong, J. T.; Min, K. R.; Kim, K. Y.

2007-06-01

The objective of this study is to establish a system for the comparative analysis of the environmental impacts, risks, health effects, and social acceptance for various electricity generation systems and a computational framework and necessary databases. In this study, the second phase of the nuclear research and development program(2002-2004), the methodologies for the comparative analysis of the environmental impacts, risks, and health effects for various electricity generation systems was investigated and applied to reference power plants. The life cycle assessment (LCA) methodology as a comparative analysis tool for the environmental impacts was adopted and applied to fossil-fueled and nuclear power plants. The scope of the analysis considered in this study are the construction, operation/fuel cycle), and demolition of each power generation system. In the risk analysis part, the empirical and analytical methods were adopted and applied to fossil-fueled and nuclear power plants. In the empirical risk assessment part, we collected historical experiences of worldwide energy-related accidents with fatalities over the last 30 years. The scope of the analysis considered in this study are the construction, operation (fuel cycle), and demolition stages of each power generation systems. The risks for the case of nuclear power plants which have potential releases of radioactive materials were estimated In a probabilistic way (PSA) by considering the occurrence of severe accidents and compared with the risks of other electricity generation systems. The health effects testimated as external cost) resulting from the operation of nuclear, coal, and hydro power systems were estimated and compared by using the program developed by the IAEA. Regarding a comprehensive comparison of the various power systems, the analytic hierarchy process (AHP) method is introduced to aggregate the diverse information under conflicting decision criteria. Social aspect is treated by a web

Effect of water resource development and management on lymphatic filariasis, and estimates of populations at risk.

Science.gov (United States)

Erlanger, Tobias E; Keiser, Jennifer; Caldas De Castro, Marcia; Bos, Robert; Singer, Burton H; Tanner, Marcel; Utzinger, Jürg

2005-09-01

Lymphatic filariasis (LF) is a debilitating disease overwhelmingly caused by Wuchereria bancrofti, which is transmitted by various mosquito species. Here, we present a systematic literature review with the following objectives: (i) to establish global and regional estimates of populations at risk of LF with particular consideration of water resource development projects, and (ii) to assess the effects of water resource development and management on the frequency and transmission dynamics of the disease. We estimate that globally, 2 billion people are at risk of LF. Among them, there are 394.5 million urban dwellers without access to improved sanitation and 213 million rural dwellers living in close proximity to irrigation. Environmental changes due to water resource development and management consistently led to a shift in vector species composition and generally to a strong proliferation of vector populations. For example, in World Health Organization (WHO) subregions 1 and 2, mosquito densities of the Anopheles gambiae complex and Anopheles funestus were up to 25-fold higher in irrigated areas when compared with irrigation-free sites. Although the infection prevalence of LF often increased after the implementation of a water project, there was no clear association with clinical symptoms. Concluding, there is a need to assess and quantify changes of LF transmission parameters and clinical manifestations over the entire course of water resource developments. Where resources allow, integrated vector management should complement mass drug administration, and broad-based monitoring and surveillance of the disease should become an integral part of large-scale waste management and sanitation programs, whose basic rationale lies in a systemic approach to city, district, and regional level health services and disease prevention.

Studies on risk estimation to public from medical radiation (III)

Energy Technology Data Exchange (ETDEWEB)

Lee, Hai Yong; Kim, Jong Hyung; Kim, Hyeog Ju; Kim, Ji Soon; Oh, Hyeon Joo; Kim, Cheol Hyeon; Yang, Hyun Kyu [Korea Food and Drug Administraion, Seoul (Korea, Republic of); Park, Chan Il [Seoul National Univ., Seoul (Korea, Republic of)

1998-06-01

A nationwide survey was conducted to give representative levels of effective doses to patient for 17 types of CT examination and also representative level of MGD (mean glandular dose) to standard breast for mammography X-ray equipment. The effective doses to patient from 16 CT scanners were estimated from measurement of CTDI (Computed Tomography Dose Index) in air by multiplying conversion coefficients which are specified by National Radiological Protection Board in United Kingdom. The lowest and hightest mean values of effective dose measured to patient from CT scanner were 0.05 mSv for IAM examination and 17.75 mSv for routine abdomen examination, respectively. The average values of 17 effective doses were lower than other results of foreign countrys' surveys. The mean glandular doses to a standard breast for 26 mammography units were estimated from measurement of the air kerma at the surface of a 40 mm plain Perspex phantom by applying conversion factors described in Report 59 of the Institute of Physical Sciences in Medicine of United Kingdom. The exposure factors for this measurement were those used clinically at each hospital. The average MGD to standard breast was 1.06 mGy in units with grid and 0.49 mGy in units without grid. These results are lower than guidance levels by IPSM and AAPM. These results will be used for risk estimation to the Korean public from the medical radiation.

Using the Violence Risk Scale-Sexual Offense version in sexual violence risk assessments: Updated risk categories and recidivism estimates from a multisite sample of treated sexual offenders.

Science.gov (United States)

Olver, Mark E; Mundt, James C; Thornton, David; Beggs Christofferson, Sarah M; Kingston, Drew A; Sowden, Justina N; Nicholaichuk, Terry P; Gordon, Audrey; Wong, Stephen C P

2018-04-30

The present study sought to develop updated risk categories and recidivism estimates for the Violence Risk Scale-Sexual Offense version (VRS-SO; Wong, Olver, Nicholaichuk, & Gordon, 2003-2017), a sexual offender risk assessment and treatment planning tool. The overarching purpose was to increase the clarity and accuracy of communicating risk assessment information that includes a systematic incorporation of new information (i.e., change) to modify risk estimates. Four treated samples of sexual offenders with VRS-SO pretreatment, posttreatment, and Static-99R ratings were combined with a minimum follow-up period of 10-years postrelease (N = 913). Logistic regression was used to model 5- and 10-year sexual and violent (including sexual) recidivism estimates across 6 different regression models employing specific risk and change score information from the VRS-SO and/or Static-99R. A rationale is presented for clinical applications of select models and the necessity of controlling for baseline risk when utilizing change information across repeated assessments. Information concerning relative risk (percentiles) and absolute risk (recidivism estimates) is integrated with common risk assessment language guidelines to generate new risk categories for the VRS-SO. Guidelines for model selection and forensic clinical application of the risk estimates are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Estimation of risk map for cohort study of Hiroshima atomic bomb survivors. 1970-2010

International Nuclear Information System (INIS)

Tonda, Tetsuji; Satoh, Kenichi; Otani, Keiko; Sato, Yuya; Maruyama, Hirofomi; Kawakami, Hideshi; Tashiro, Satoshi; Hoshi, Masaharu; Ohtaki, Megu

2012-01-01

A risk map (map I) involving the effects of direct A-bomb exposure and of other confounding factors was estimated to analyze the death risk in the geographic distribution, and another risk map (map II) was also made by subtracting the direct exposure effect to see the confounder effect. The cohort was 37,382/157,327 survivors at Jan. 1, 1970, whose positional coordinates at the exposure were known, and was followed up until Dec. 31, 2009. For survival analysis, the endpoint was defined to be death (total 19,119) by regarding other 18,263 as censoring. Confounding factors were sex, age at the exposure, exposed dose and shielded condition. Maps I and II were depicted using the hazard ratio at the exposed position relative to the hypocenter, which was estimated by previously reported hazard model functions. Map I was found to be rather similar to concentric circle of the hypocenter, but to be tended a bit distorted toward northwest area. The distortion was clearer in the map II, indicating that death causes other than direct exposure existed. The confounder was thought to be the indirect exposure through the black rain, residual radiation and/or internal exposure, which awaiting future investigation. (T.T.)

Use of health effect risk estimates and uncertainty in formal regulatory proceedings: a case study involving atmospheric particulates

International Nuclear Information System (INIS)

Habegger, L.J.; Oezkaynak, A.H.

1984-01-01

Coal combustion particulates are released to the atmosphere by power plants supplying electrical to the nuclear fuel cycle. This paper presents estimates of the public health risks associated with the release of these particulates at a rate associated with the annual nuclear fuel production requirements for a nuclear power plan. Utilization of these risk assessments as a new component in the formal evaluation of total risks from nuclear power plants is discussed. 23 references, 3 tables

Effects of risk estimation tendency on risk perception at the Tohoku Disaster

International Nuclear Information System (INIS)

Nakagawa, Yuri; Tsuchida, Shoji; Tsujikawa, Norifumi; Shiotani, Takamasa

2012-01-01

The Tohoku Disaster showed the underlying risks of earthquake, tsunami, nuclear power plant accidents and debris removal. The ability to understand the risk and act appropriately has been widely discussed among the professionals as well within the community. In Oct 2011, an Online survey. Using the correspondence analysis approach, the data collected the free-answer question 'What do you remember most regarding news on the Tohoku Disaster' was analyzed. The relationship between the cognitive trade-off factors, zero-risk factors and elaboration tendency factors, and risk perception among the people following the Tohoku Disaster were discussed. (author)

Stochastic risk estimation from medical x-ray diagnostic examinations, 2. Risk estimates of individuals from x-ray diagnosis

Energy Technology Data Exchange (ETDEWEB)

Hashizume, T; Maruyama, T; Noda, Y; Iwai, K; Tateno, Y [National Inst. of Radiological Sciences, Chiba (Japan); Nishizawa, K

1981-01-01

The risks of genetic, leukemia and malignant diseases from medical X-ray diagnostic examinations were estimated using the frequency of radiographic and fluoroscopic exposures per diagnostic examination, child expectancy, leukemia and malignancy significant factors, and using a weighting factor determined on the basis of data concerning the cancer mortality among atomic bomb survivors in Nagasaki and of a recommendation of International Commission of Radiological Protection. The organ or tissue doses with respect to the stochastic risks were determined with ionization chambers and thermoluminescent dosimeters placed at the positions of the organs or tissues in a RANDO woman phantom which was exposed to diagnostic X-rays according to technical factors of typical radiographic and fluoroscopic examinations obtained from a nationwide survey. The resultant risks by age-group and type of radiographic and fluoroscopic examination are tabulated in terms of risk level of 10/sup -6/. In general, the total risk defined as the sum of genetic, leukemia and malignant risks was a high value for the X-ray diagnosis of digestive organs involving barium meal and barium enema. For example, the total risk for young age-group was 100 to 200 x 10/sup -6/ for the X-ray diagnosis of digestive organs. The total risk from the chest radiography was lower value as compared with the risk from the X-ray diagnosis of other organs or tissues. On the contrary, the risk from the chest tomography was comparable to the risk from the diagnosis of digestive organs. The total risk decreased with increasing of age for every X-ray diagnostic examination.

Estimation of unit risk for coke oven emissions

International Nuclear Information System (INIS)

Moolgavkar, S.H.; Luebeck, E.G.; Anderson, E.L.

1998-01-01

In 1984, based on epidemiological data on cohorts of coke oven workers, USEPA estimated a unit risk for lung cancer associated with continuous exposure from birth to 1 microg/m 3 of coke oven emissions, of 6.2 x 10 -4 . This risk assessment was based on information on the cohorts available through 1966. Follow-up of these cohorts has now been extended to 1982 and, moreover, individual job histories, which were not available in 1984, have been constructed. In this study, lung cancer mortality in these cohorts of coke oven workers with extended follow-up was analyzed using standard techniques of survival analysis and a new approach based on the two stage clonal expansion model of carcinogenesis. The latter approach allows the explicit consideration of detailed patterns of exposure of each individual in the cohort. The analyses used the extended follow-up data through 1982 and the detailed job histories now available. Based on these analyses, the best estimate of unit risk is 1.5 x 10 -4 with 95% confidence interval = 1.2 x 10 -4 --1.8 x 10 -4

Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

Directory of Open Access Journals (Sweden)

Adeleye Bamise

2017-12-01

Full Text Available The preference for computed tomography (CT for the clinical assessment of pulmonary tuberculosis (PTB infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05 between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05 and female patients (r2 = 0.989, P < 0.05. The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively. These variations provide an indication that the use of a scanner optimizing protocol is imperative.

Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections

Science.gov (United States)

Adeleye, Bamise; Chetty, Naven

2017-12-01

The preference for computed tomography (CT) for the clinical assessment of pulmonary tuberculosis (PTB) infections has increased the concern about the potential risk of cancer in exposed patients. In this study, we investigated the correlation between cancer risk and radiation doses from different CT scanners, assuming an equivalent scan protocol. Radiation doses from three 16-slice units were estimated using the CT-Expo dosimetry software version 2.4 and standard CT scan protocol for patients with suspected PTB infections. The lifetime risk of cancer for each scanner was determined using the methodology outlined in the BEIR VII report. Organ doses were significantly different (P < 0.05) between the scanners. The calculated effective dose for scanner H2 is 34% and 37% higher than scanners H3 and H1 respectively. A high and statistically significant correlation was observed between estimated lifetime cancer risk for both male (r2 = 0.943, P < 0.05) and female patients (r2 = 0.989, P < 0.05). The risk variation between the scanners was slightly higher than 2% for all ages but was much smaller for specific ages for male and female patients (0.2% and 0.7%, respectively). These variations provide an indication that the use of a scanner optimizing protocol is imperative.

A new way to estimate the direct and indirect rebound effect and other rebound indicators

International Nuclear Information System (INIS)

Freire-González, Jaume

2017-01-01

Some progress has been done during the last years on the methods and provision of empirical evidence on the direct and indirect rebound effect. However, these methods are complex, and sometimes require some specific economic knowledge. The development of risk and vulnerability rebound indicators for economies can be a useful tool to help the research community, policy-makers and other practitioners to understand and tackle the rebound effect. This research shows a new analytical way to obtain the direct and indirect rebound effect from the direct rebound effect and the use of energy input-output coefficients, and proposes three risk and vulnerability rebound indicators to show the effects of energy efficiency improvements in households on overall energy consumption. An estimation of these indicators has been conducted for the EU-27 countries. - Highlights: • A new method to estimate direct and indirect rebound effect is shown. • Three indicators are developed to assess risk and vulnerability to rebound. • An estimation of rebound indicators has been carried out for the EU-27 economies.

Environmental risk assessment of selected organic chemicals based on TOC test and QSAR estimation models.

Science.gov (United States)

Chi, Yulang; Zhang, Huanteng; Huang, Qiansheng; Lin, Yi; Ye, Guozhu; Zhu, Huimin; Dong, Sijun

2018-02-01

Environmental risks of organic chemicals have been greatly determined by their persistence, bioaccumulation, and toxicity (PBT) and physicochemical properties. Major regulations in different countries and regions identify chemicals according to their bioconcentration factor (BCF) and octanol-water partition coefficient (Kow), which frequently displays a substantial correlation with the sediment sorption coefficient (Koc). Half-life or degradability is crucial for the persistence evaluation of chemicals. Quantitative structure activity relationship (QSAR) estimation models are indispensable for predicting environmental fate and health effects in the absence of field- or laboratory-based data. In this study, 39 chemicals of high concern were chosen for half-life testing based on total organic carbon (TOC) degradation, and two widely accepted and highly used QSAR estimation models (i.e., EPI Suite and PBT Profiler) were adopted for environmental risk evaluation. The experimental results and estimated data, as well as the two model-based results were compared, based on the water solubility, Kow, Koc, BCF and half-life. Environmental risk assessment of the selected compounds was achieved by combining experimental data and estimation models. It was concluded that both EPI Suite and PBT Profiler were fairly accurate in measuring the physicochemical properties and degradation half-lives for water, soil, and sediment. However, the half-lives between the experimental and the estimated results were still not absolutely consistent. This suggests deficiencies of the prediction models in some ways, and the necessity to combine the experimental data and predicted results for the evaluation of environmental fate and risks of pollutants. Copyright © 2016. Published by Elsevier B.V.

Patient-specific radiation dose and cancer risk estimation in CT: Part II. Application to patients

Energy Technology Data Exchange (ETDEWEB)

Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Toncheva, Greta; Yoshizumi, Terry T.; Frush, Donald P. [Medical Physics Graduate Program, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Department of Physics, and Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Duke Radiation Dosimetry Laboratory, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Duke Radiation Dosimetry Laboratory, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27705 (United States); Division of Pediatric Radiology, Department of Radiology, Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States)

2011-01-15

Purpose: Current methods for estimating and reporting radiation dose from CT examinations are largely patient-generic; the body size and hence dose variation from patient to patient is not reflected. Furthermore, the current protocol designs rely on dose as a surrogate for the risk of cancer incidence, neglecting the strong dependence of risk on age and gender. The purpose of this study was to develop a method for estimating patient-specific radiation dose and cancer risk from CT examinations. Methods: The study included two patients (a 5-week-old female patient and a 12-year-old male patient), who underwent 64-slice CT examinations (LightSpeed VCT, GE Healthcare) of the chest, abdomen, and pelvis at our institution in 2006. For each patient, a nonuniform rational B-spine (NURBS) based full-body computer model was created based on the patient's clinical CT data. Large organs and structures inside the image volume were individually segmented and modeled. Other organs were created by transforming an existing adult male or female full-body computer model (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. A Monte Carlo program previously developed and validated for dose simulation on the LightSpeed VCT scanner was used to estimate patient-specific organ dose, from which effective dose and risks of cancer incidence were derived. Patient-specific organ dose and effective dose were compared with patient-generic CT dose quantities in current clinical use: the volume-weighted CT dose index (CTDI{sub vol}) and the effective dose derived from the dose-length product (DLP). Results: The effective dose for the CT examination of the newborn patient (5.7 mSv) was higher but comparable to that for the CT examination of the teenager patient (4.9 mSv) due to the size-based clinical CT protocols at our institution, which employ lower scan techniques for smaller

Problems and solutions in the estimation of genetic risks from radiation and chemicals

International Nuclear Information System (INIS)

Russell, W.L.

1980-01-01

Extensive investigations with mice on the effects of various physical and biological factors, such as dose rate, sex and cell stage, on radiation-induced mutation have provided an evaluation of the genetics hazards of radiation in man. The mutational results obtained in both sexes with progressive lowering of the radiation dose rate have permitted estimation of the mutation frequency expected under the low-level radiation conditions of most human exposure. Supplementing the studies on mutation frequency are investigations on the phenotypic effects of mutations in mice, particularly anatomical disorders of the skeleton, which allow an estimation of the degree of human handicap associated with the occurrence of parallel defects in man. Estimation of the genetic risk from chemical mutagens is much more difficult, and the research is much less advanced. Results on transmitted mutations in mice indicate a poor correlation with mutation induction in non-mammalian organisms

Future flood risk estimates along the river Rhine

Directory of Open Access Journals (Sweden)

A. H. te Linde

2011-02-01

Full Text Available In Europe, water management is moving from flood defence to a risk management approach, which takes both the probability and the potential consequences of flooding into account. It is expected that climate change and socio-economic development will lead to an increase in flood risk in the Rhine basin. To optimize spatial planning and flood management measures, studies are needed that quantify future flood risks and estimate their uncertainties. In this paper, we estimated the current and future fluvial flood risk in 2030 for the entire Rhine basin in a scenario study. The change in value at risk is based on two land-use projections derived from a land-use model representing two different socio-economic scenarios. Potential damage was calculated by a damage model, and changes in flood probabilities were derived from two climate scenarios and hydrological modeling. We aggregated the results into seven sections along the Rhine. It was found that the annual expected damage in the Rhine basin may increase by between 54% and 230%, of which the major part (~ three-quarters can be accounted for by climate change. The highest current potential damage can be found in the Netherlands (110 billion €, compared with the second (80 billion € and third (62 billion € highest values in two areas in Germany. Results further show that the area with the highest fluvial flood risk is located in the Lower Rhine in Nordrhein-Westfalen in Germany, and not in the Netherlands, as is often perceived. This is mainly due to the higher flood protection standards in the Netherlands as compared to Germany.

A study on the estimation method of nuclear accident risk cost

International Nuclear Information System (INIS)

Matsuo, Yuji

2016-01-01

The methodology of estimating nuclear accident risk cost, as a part of nuclear power generation cost, has hardly been established due mainly to the extremely wide range of the estimation of the accident frequency. This study estimates the expected nuclear accident frequency for Japan, making use of the method of Bayesian statistics, which exploits both the information obtained by Probabilistic Risk Assessment (PRA) and the observed historical accident frequencies. Using the PRA estimation of the Containment Failure Frequency (CFF) for Tomari nuclear power plant unit 3 of Hokkaido Electric Power Company (average: 2.1 x 10 -4 , 95th percentile: 7.7 x 10 -4 ) and the actual large-scale accident frequency (once in 1,460 reactor-years), the posterior CFF was estimated at 3.8 x 10 -4 . This study also took into account the 'external' factor causing unexpected nuclear accidents, concluding that such factor could result in higher CFF estimations, especially with larger observed accident numbers. (author)

Estimating and explaining the effect of education and income on head and neck cancer risk: INHANCE consortium pooled analysis of 31 case-control studies from 27 countries.

Science.gov (United States)

Conway, David I; Brenner, Darren R; McMahon, Alex D; Macpherson, Lorna M D; Agudo, Antonio; Ahrens, Wolfgang; Bosetti, Cristina; Brenner, Hermann; Castellsague, Xavier; Chen, Chu; Curado, Maria Paula; Curioni, Otávio A; Dal Maso, Luigino; Daudt, Alexander W; de Gois Filho, José F; D'Souza, Gypsyamber; Edefonti, Valeria; Fabianova, Eleonora; Fernandez, Leticia; Franceschi, Silvia; Gillison, Maura; Hayes, Richard B; Healy, Claire M; Herrero, Rolando; Holcatova, Ivana; Jayaprakash, Vijayvel; Kelsey, Karl; Kjaerheim, Kristina; Koifman, Sergio; La Vecchia, Carlo; Lagiou, Pagona; Lazarus, Philip; Levi, Fabio; Lissowska, Jolanta; Luce, Daniele; Macfarlane, Tatiana V; Mates, Dana; Matos, Elena; McClean, Michael; Menezes, Ana M; Menvielle, Gwenn; Merletti, Franco; Morgenstern, Hal; Moysich, Kirsten; Müller, Heiko; Muscat, Joshua; Olshan, Andrew F; Purdue, Mark P; Ramroth, Heribert; Richiardi, Lorenzo; Rudnai, Peter; Schantz, Stimson; Schwartz, Stephen M; Shangina, Oxana; Simonato, Lorenzo; Smith, Elaine; Stucker, Isabelle; Sturgis, Erich M; Szeszenia-Dabrowska, Neonila; Talamini, Renato; Thomson, Peter; Vaughan, Thomas L; Wei, Qingyi; Winn, Deborah M; Wunsch-Filho, Victor; Yu, Guo-Pei; Zhang, Zuo-Feng; Zheng, Tongzhang; Znaor, Ariana; Boffetta, Paolo; Chuang, Shu-Chun; Ghodrat, Marianoosh; Amy Lee, Yuan-Chin; Hashibe, Mia; Brennan, Paul

2015-03-01

Low socioeconomic status has been reported to be associated with head and neck cancer risk. However, previous studies have been too small to examine the associations by cancer subsite, age, sex, global region and calendar time and to explain the association in terms of behavioral risk factors. Individual participant data of 23,964 cases with head and neck cancer and 31,954 controls from 31 studies in 27 countries pooled with random effects models. Overall, low education was associated with an increased risk of head and neck cancer (OR = 2.50; 95% CI = 2.02 - 3.09). Overall one-third of the increased risk was not explained by differences in the distribution of cigarette smoking and alcohol behaviors; and it remained elevated among never users of tobacco and nondrinkers (OR = 1.61; 95% CI = 1.13 - 2.31). More of the estimated education effect was not explained by cigarette smoking and alcohol behaviors: in women than in men, in older than younger groups, in the oropharynx than in other sites, in South/Central America than in Europe/North America and was strongest in countries with greater income inequality. Similar findings were observed for the estimated effect of low versus high household income. The lowest levels of income and educational attainment were associated with more than 2-fold increased risk of head and neck cancer, which is not entirely explained by differences in the distributions of behavioral risk factors for these cancers and which varies across cancer sites, sexes, countries and country income inequality levels. © 2014 UICC.

Estimating Bird / Aircraft Collision Probabilities and Risk Utilizing Spatial Poisson Processes

Science.gov (United States)

2012-06-10

ESTIMATING BIRD/AIRCRAFT COLLISION PROBABILITIES AND RISK UTILIZING SPATIAL POISSON PROCESSES GRADUATE...AND RISK UTILIZING SPATIAL POISSON PROCESSES GRADUATE RESEARCH PAPER Presented to the Faculty Department of Operational Sciences...COLLISION PROBABILITIES AND RISK UTILIZING SPATIAL POISSON PROCESSES Brady J. Vaira, BS, MS Major, USAF Approved

Estimation of wildfire size and risk changes due to fuels treatments

Science.gov (United States)

Cochrane, M.A.; Moran, C.J.; Wimberly, M.C.; Baer, A.D.; Finney, M.A.; Beckendorf, K.L.; Eidenshink, J.; Zhu, Z.

2012-01-01

Human land use practices, altered climates, and shifting forest and fire management policies have increased the frequency of large wildfires several-fold. Mitigation of potential fire behaviour and fire severity have increasingly been attempted through pre-fire alteration of wildland fuels using mechanical treatments and prescribed fires. Despite annual treatment of more than a million hectares of land, quantitative assessments of the effectiveness of existing fuel treatments at reducing the size of actual wildfires or how they might alter the risk of burning across landscapes are currently lacking. Here, we present a method for estimating spatial probabilities of burning as a function of extant fuels treatments for any wildland fire-affected landscape. We examined the landscape effects of more than 72 000 ha of wildland fuel treatments involved in 14 large wildfires that burned 314 000 ha of forests in nine US states between 2002 and 2010. Fuels treatments altered the probability of fire occurrence both positively and negatively across landscapes, effectively redistributing fire risk by changing surface fire spread rates and reducing the likelihood of crowning behaviour. Trade offs are created between formation of large areas with low probabilities of increased burning and smaller, well-defined regions with reduced fire risk.

Estimating mortality risk reduction and economic benefits from controlling ozone air pollution

National Research Council Canada - National Science Library

Committee on Estimating Mortality Risk Reduction Benefits from Decreasing Tropospheric Ozone Exposure

2008-01-01

... in life expectancy, and to assess methods for estimating the monetary value of the reduced risk of premature death and increased life expectancy in the context of health-benefits analysis. Estimating Mortality Risk Reduction and Economic Benefits from Controlling Ozone Air Pollution details the committee's findings and posits several recommendations to address these issues.

Estimating twin concordance for bivariate competing risks twin data

DEFF Research Database (Denmark)

Scheike, Thomas; Holst, Klaus K.; Hjelmborg, Jacob B.

2014-01-01

For twin time-to-event data, we consider different concordance probabilities, such as the casewise concordance that are routinely computed as a measure of the lifetime dependence/correlation for specific diseases. The concordance probability here is the probability that both twins have experience...... events with the competing risk death. We thus aim to quantify the degree of dependence through the casewise concordance function and show a significant genetic component...... the event of interest. Under the assumption that both twins are censored at the same time, we show how to estimate this probability in the presence of right censoring, and as a consequence, we can then estimate the casewise twin concordance. In addition, we can model the magnitude of within pair dependence...... over time, and covariates may be further influential on the marginal risk and dependence structure. We establish the estimators large sample properties and suggest various tests, for example, for inferring familial influence. The method is demonstrated and motivated by specific twin data on cancer...

Patient- and cohort-specific dose and risk estimation for abdominopelvic CT: a study based on 100 patients

Science.gov (United States)

Tian, Xiaoyu; Li, Xiang; Segars, W. Paul; Frush, Donald P.; Samei, Ehsan

2012-03-01

The purpose of this work was twofold: (a) to estimate patient- and cohort-specific radiation dose and cancer risk index for abdominopelvic computer tomography (CT) scans; (b) to evaluate the effects of patient anatomical characteristics (size, age, and gender) and CT scanner model on dose and risk conversion coefficients. The study included 100 patient models (42 pediatric models, 58 adult models) and multi-detector array CT scanners from two commercial manufacturers (LightSpeed VCT, GE Healthcare; SOMATOM Definition Flash, Siemens Healthcare). A previously-validated Monte Carlo program was used to simulate organ dose for each patient model and each scanner, from which DLP-normalized-effective dose (k factor) and DLP-normalized-risk index values (q factor) were derived. The k factor showed exponential decrease with increasing patient size. For a given gender, q factor showed exponential decrease with both increasing patient size and patient age. The discrepancies in k and q factors across scanners were on average 8% and 15%, respectively. This study demonstrates the feasibility of estimating patient-specific organ dose and cohort-specific effective dose and risk index in abdominopelvic CT requiring only the knowledge of patient size, gender, and age.

Health effects of risk-assessment categories

International Nuclear Information System (INIS)

Kramer, C.F.; Rybicka, K.; Knutson, A.; Morris, S.C.

1983-10-01

Environmental and occupational health effects associated with exposures to various chemicals are a subject of increasing concern. One recently developed methodology for assessing the health impacts of various chemical compounds involves the classification of similar chemicals into risk-assessment categories (RACs). This report reviews documented human health effects for a broad range of pollutants, classified by RACs. It complements other studies that have estimated human health effects by RAC based on analysis and extrapolation of data from animal research

Health effects of risk-assessment categories

Energy Technology Data Exchange (ETDEWEB)

Kramer, C.F.; Rybicka, K.; Knutson, A.; Morris, S.C.

1983-10-01

Environmental and occupational health effects associated with exposures to various chemicals are a subject of increasing concern. One recently developed methodology for assessing the health impacts of various chemical compounds involves the classification of similar chemicals into risk-assessment categories (RACs). This report reviews documented human health effects for a broad range of pollutants, classified by RACs. It complements other studies that have estimated human health effects by RAC based on analysis and extrapolation of data from animal research.

Health effects estimation: Methods and results for uranium mill tailings contaminated properties

International Nuclear Information System (INIS)

Denham, D.H.; Cross, F.T.; Soldat, J.K.

1990-01-01

This paper describes methods for estimating potential health effects from exposure to uranium mill tailings and presents a summary of risk projections for 50 contaminated properties (residences, schools, churches, and businesses) in the US. The methods provide realistic estimates of cancer risk to exposed individuals based on property-specific occupancy and contamination patterns. External exposure to gamma radiation, inhalation of radon daughters, and consumption of food products grown in radium-contaminated soil are considered. Most of the projected risk was from indoor exposure to radon daughters; however, for some properties the risk from consumption of locally grown food products is similar to that from radon daughters. In all cases, the projected number of lifetime cancer deaths for specific properties is less than one, but for some properties the increase in risk over that normally expected is greater than 100%

Bayesian parameter estimation in probabilistic risk assessment

International Nuclear Information System (INIS)

Siu, Nathan O.; Kelly, Dana L.

1998-01-01

Bayesian statistical methods are widely used in probabilistic risk assessment (PRA) because of their ability to provide useful estimates of model parameters when data are sparse and because the subjective probability framework, from which these methods are derived, is a natural framework to address the decision problems motivating PRA. This paper presents a tutorial on Bayesian parameter estimation especially relevant to PRA. It summarizes the philosophy behind these methods, approaches for constructing likelihood functions and prior distributions, some simple but realistic examples, and a variety of cautions and lessons regarding practical applications. References are also provided for more in-depth coverage of various topics

Model-based Small Area Estimates of Cancer Risk Factors and Screening Behaviors - Small Area Estimates

Science.gov (United States)

These model-based estimates use two surveys, the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS). The two surveys are combined using novel statistical methodology.

Association of type D personality with unhealthy lifestyle, and estimated risk of coronary events in the general Icelandic population.

Science.gov (United States)

Svansdottir, Erla; Denollet, Johan; Thorsson, Bolli; Gudnason, Thorarinn; Halldorsdottir, Sigrun; Gudnason, Vilmundur; van den Broek, Krista C; Karlsson, Hrobjartur D

2013-04-01

Type D personality is associated with an increased morbidity and mortality risk in cardiovascular disease patients, but the mechanisms explaining this risk are unclear. We examined whether Type D was associated with coronary artery disease (CAD) risk factors, estimated risk of developing CAD, and previous cardiac events. Cross-sectional study in the general Icelandic population. A random sample of 4753 individuals (mean age 49.1 ± 12.0 years; 49% men) from the REFINE-Reykjavik study completed assessments for Type D personality and conventional CAD risk factors. Ten-year risk of developing CAD was estimated with the Icelandic risk calculator. Type D personality (22% of sample) was associated with a higher prevalence of hypertension (35 vs. 31%, p = 0.009), but less use of hypertension medication (58 vs. 65%, p = 0.013) in hypertensives, more diabetes (6 vs. 4%, p = 0.023), wider waist circumference (p = 0.007), and elevated body mass index (p = 0.025) and blood lipids (p lifestyle-related CAD risk factors, a higher estimated risk of developing CAD, and higher incidence of previous cardiac events. Unhealthy lifestyles may partly explain the adverse cardiovascular effect of Type D personality.

Risk Estimates and Risk Factors Related to Psychiatric Inpatient Suicide—An Overview

Directory of Open Access Journals (Sweden)

Trine Madsen

2017-03-01

Full Text Available People with mental illness have an increased risk of suicide. The aim of this paper is to provide an overview of suicide risk estimates among psychiatric inpatients based on the body of evidence found in scientific peer-reviewed literature; primarily focusing on the relative risks, rates, time trends, and socio-demographic and clinical risk factors of suicide in psychiatric inpatients. Psychiatric inpatients have a very high risk of suicide relative to the background population, but it remains challenging for clinicians to identify those patients that are most likely to die from suicide during admission. Most studies are based on low power, thus compromising quality and generalisability. The few studies with sufficient statistical power mainly identified non-modifiable risk predictors such as male gender, diagnosis, or recent deliberate self-harm. Also, the predictive value of these predictors is low. It would be of great benefit if future studies would be based on large samples while focusing on modifiable predictors over the course of an admission, such as hopelessness, depressive symptoms, and family/social situations. This would improve our chances of developing better risk assessment tools.

RiD: A New Approach to Estimate the Insolvency Risk

Directory of Open Access Journals (Sweden)

Marco Aurélio dos Santos Sanfins

2014-10-01

Full Text Available Given the recent international crises and the increasing number of defaults, several researchers have attempted to develop metrics that calculate the probability of insolvency with higher accuracy. The approaches commonly used, however, do not consider the credit risk nor the severity of the distance between receivables and obligations among different periods. In this paper we mathematically present an approach that allow us to estimate the insolvency risk by considering not only future receivables and obligations, but the severity of the distance between them and the quality of the respective receivables. Using Monte Carlo simulations and hypothetical examples, we show that our metric is able to estimate the insolvency risk with high accuracy. Moreover, our results suggest that in the absence of a smooth distribution between receivables and obligations, there is a non-null insolvency risk even when the present value of receivables is larger than the present value of the obligations.

Estimation of baseline lifetime risk of developed cancer related to radiation exposure in China

International Nuclear Information System (INIS)

Li Xiaoliang; Niu Haowei; Sun Quanfu; Ma Weidong

2011-01-01

Objective: To introduce the general international method for estimation of lifetime risk of developed cancer, and to estimate the lifetime risk baseline values of several kinds of cancers related to radiation exposures in China. Methods: The risk estimation was based on the data from Chinese Cancer Registry Annual Report (2010) and China Population and Employment Statistics Yearbook (2009), and made according to the method previously published by National Cancer Institute (NCI) in USA. Results: The lifetime risk of all cancer in China in 2007 was estimated to be 27.77%, that of lung cancer 5.96%, that of breast cancer for female 3.34%, that of all leukemia 0.14%, that of thyroid cancer 0.37%. The lifetime risks of all cancer were estimated to be 32.74% for males and 24.73% for females, and that was 36.47% for urban residents and 26.79% for rural people. Conclusions: The lifetime risk of all cancer for males in 2007 was about 1.25 times as much as that for females. The value of all cancer for urban residents was about 1.35 times as much as that for rural residents. The lifetime risk of developed cancers in 2007 in China is lower than that in the developed countries,such as Japan. (authors)

Estimated risk from exposure to radon decay products in US homes

International Nuclear Information System (INIS)

Nero, A.V. Jr.

1986-05-01

Recent analyses now permit direct estimation of the risks of lung cancer from radon decay products in US homes. Analysis of data from indoor monitoring in single-family homes yields a tentative frequency distribution of annual-average 222 Rn concentrations averaging 55 Bq m -3 and having 2% of homes exceeding 300 Bq m -3 . Application of the results of occupational epidemiological studies, either directly or using recent advances in lung dosimetry, to indoor exposures suggests that the average indoor concentration entails a lifetime risk of lung cancer of 0.3% or about 10% of the total risk of lung cancer. The risk to individuals occupying the homes with 300 Bq m -3 or more for their lifetimes is estimated to exceed 2%, with risks from the homes with thousands of Bq m -3 correspondingly higher, even exceeding the total risk of premature death due to cigarette smoking. The potential for such average and high-level risks in ordinary homes forces development of a new perspective on environmental exposures

How much does HDL cholesterol add to risk estimation? A report from the SCORE Investigators.

LENUS (Irish Health Repository)

Cooney, Marie Therese

2009-06-01

Systematic COronary Risk Evaluation (SCORE), the risk estimation system recommended by the European guidelines on cardiovascular disease prevention, estimates 10-year risk of cardiovascular disease mortality based on age, sex, country of origin, systolic blood pressure, smoking status and either total cholesterol (TC) or TC\\/high-density lipoprotein cholesterol (HDL-C) ratio. As, counterintuitively, these two systems perform very similarly, we have investigated whether incorporating HDL-C and TC as separate variables improves risk estimation.

Estimates of radiological risk from depleted uranium weapons in war scenarios.

Science.gov (United States)

Durante, Marco; Pugliese, Mariagabriella

2002-01-01

Several weapons used during the recent conflict in Yugoslavia contain depleted uranium, including missiles and armor-piercing incendiary rounds. Health concern is related to the use of these weapons, because of the heavy-metal toxicity and radioactivity of uranium. Although chemical toxicity is considered the more important source of health risk related to uranium, radiation exposure has been allegedly related to cancers among veterans of the Balkan conflict, and uranium munitions are a possible source of contamination in the environment. Actual measurements of radioactive contamination are needed to assess the risk. In this paper, a computer simulation is proposed to estimate radiological risk related to different exposure scenarios. Dose caused by inhalation of radioactive aerosols and ground contamination induced by Tomahawk missile impact are simulated using a Gaussian plume model (HOTSPOT code). Environmental contamination and committed dose to the population resident in contaminated areas are predicted by a food-web model (RESRAD code). Small values of committed effective dose equivalent appear to be associated with missile impacts (50-y CEDE radiological risk. These computer simulations suggest that little radiological risk is associated to the use of depleted uranium weapons.

Differential Effects for Sexual Risk Behavior: An Application of Finite Mixture Regression

OpenAIRE

Lanza, Stephanie T.; Kugler, Kari C.; Mathur, Charu

2011-01-01

Understanding the multiple factors that place individuals at risk for sexual risk behavior is critical for developing effective intervention programs. Regression-based methods are commonly used to estimate the average effects of risk factors, however such results can be difficult to translate to prevention implications at the individual level. Although differential effects can be examined to some extent by including interaction terms, as risk factors and moderators are added to the model inte...

Dose-response relationships and risk estimates for the induction of cancer due to low doses of low-LET radiation

International Nuclear Information System (INIS)

Elaguppillai, V.

1981-01-01

Risk estimates for radiation-induced cancer at low doses can be obtained only by extrapolation from the known effects at high doses and high dose rates, using a suitable dose-response model. The applicability of three different models, linear, sublinear and supralinear, are discussed in this paper. Several experimental studies tend to favour a sublinear dose-response model (linear-quadratic model) for low-LET radiation. However, human epidemiological studies do not exclude any of the dose-response relationships. The risk estimates based on linear and linear quadratic dose-response models are compared and it is concluded that, for low-LET radiation, the linear dose-response model would probably over-estimate the actual risk of cancer by a factor of two or more. (author)

Prediction of cardiovascular outcome by estimated glomerular filtration rate and estimated creatinine clearance in the high-risk hypertension population of the VALUE trial.

Science.gov (United States)

Ruilope, Luis M; Zanchetti, Alberto; Julius, Stevo; McInnes, Gordon T; Segura, Julian; Stolt, Pelle; Hua, Tsushung A; Weber, Michael A; Jamerson, Ken

2007-07-01

Reduced renal function is predictive of poor cardiovascular outcomes but the predictive value of different measures of renal function is uncertain. We compared the value of estimated creatinine clearance, using the Cockcroft-Gault formula, with that of estimated glomerular filtration rate (GFR), using the Modification of Diet in Renal Disease (MDRD) formula, as predictors of cardiovascular outcome in 15 245 high-risk hypertensive participants in the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial. For the primary end-point, the three secondary end-points and for all-cause death, outcomes were compared for individuals with baseline estimated creatinine clearance and estimated GFR or = 60 ml/min using hazard ratios and 95% confidence intervals. Coronary heart disease, left ventricular hypertrophy, age, sex and treatment effects were included as covariates in the model. For each end-point considered, the risk in individuals with poor renal function at baseline was greater than in those with better renal function. Estimated creatinine clearance (Cockcroft-Gault) was significantly predictive only of all-cause death [hazard ratio = 1.223, 95% confidence interval (CI) = 1.076-1.390; P = 0.0021] whereas estimated GFR was predictive of all outcomes except stroke. Hazard ratios (95% CIs) for estimated GFR were: primary cardiac end-point, 1.497 (1.332-1.682), P cause death, 1.231 (1.098-1.380), P = 0.0004. These results indicate that estimated glomerular filtration rate calculated with the MDRD formula is more informative than estimated creatinine clearance (Cockcroft-Gault) in the prediction of cardiovascular outcomes.

Prospect theory based estimation of drivers' risk attitudes in route choice behaviors.

Science.gov (United States)

Zhou, Lizhen; Zhong, Shiquan; Ma, Shoufeng; Jia, Ning

2014-12-01

This paper applied prospect theory (PT) to describe drivers' route choice behavior under Variable Message Sign (VMS), which presented visual traffic information to assist them to make route choice decisions. A quite rich empirical data from questionnaire and field spot was used to estimate parameters of PT. In order to make the parameters more realistic with drivers' attitudes, they were classified into different types by significant factors influencing their behaviors. Based on the travel time distribution of alternative routes and route choice results from questionnaire, the parameterized value function of each category was figured out, which represented drivers' risk attitudes and choice characteristics. The empirical verification showed that the estimates were acceptable and effective. The result showed drivers' risk attitudes and route choice characteristics could be captured by PT under real-time information shown on VMS. For practical application, once drivers' route choice characteristics and parameters were identified, their route choice behavior under different road conditions could be predicted accurately, which was the basis of traffic guidance measures formulation and implementation for targeted traffic management. Moreover, the heterogeneous risk attitudes among drivers should be considered when releasing traffic information and regulating traffic flow. Copyright © 2014 Elsevier Ltd. All rights reserved.

Possibility of use of plat test systems for estimation of degree risk at radiation influence

International Nuclear Information System (INIS)

Gogebashvili, M.E.; Ivanishvili, N.I.

2010-01-01

Full text : Now one of the major problems of radiobiology is studying of degree risks at influence of small doses of an ionizing radiation. It is known, that not tumoral forms of the remote pathology are not stochastic, threshold, reactions of an organism to beam influence, frequency and weight depend on a dose, while carcinogenic and genetic effects (stochastic reactions) - frequency raises with dose increase. Last years the general hypothesis for definition of the raised risk in the irradiated populations, based on the theoretical analysis of extensive researches of various biological objects and epidemiological data, assumes existence of difficult parities between a dose of an irradiation and frequency of investigated effect. In this aspect the special importance is got by biological models with which help reception of quantitative parameters of influence of modifying factors for creation of more exact systems of monitoring of the remote radiobiological effects is possible. One of such systems is reciprocal grows reaction of stamen threads of plant tradescantia. At the heart of action of the given biomodel that growth tradescantia threads occurs from one initial cell is, and level of its radiating damage is shown in number of the subsequent cellular generation during the postradiating period. For an estimation of adequacy of the given model we had been chose two kinds tradescantia - Tradescantia virginiana L. and Tradescantia rosea Vent. It is notes, that at identical quantity of chromosomes their volume interface nucleus composable at Tradescantia virginiana L. 63.7 μ 3 , and at T.rosea Vent. - 38.5 μ 3 . Thus at interpretation of data it was possible to estimate them with the target theory. In work two basic criteria of an estimation of radiating damage - quantity of viable pollen threads and quantity of viable cells in each of threads have been used. The received results have shown strict correlation of reciprocal postradiating effects between used variants

The role of risk perception in making flood risk management more effective

Science.gov (United States)

Buchecker, M.; Salvini, G.; Di Baldassarre, G.; Semenzin, E.; Maidl, E.; Marcomini, A.

2013-11-01

Over the last few decades, Europe has suffered from a number of severe flood events and, as a result, there has been a growing interest in probing alternative approaches to managing flood risk via prevention measures. A literature review reveals that, although in the last decades risk evaluation has been recognized as key element of risk management, and risk assessment methodologies (including risk analysis and evaluation) have been improved by including social, economic, cultural, historical and political conditions, the theoretical schemes are not yet applied in practice. One main reason for this shortcoming is that risk perception literature is mainly of universal and theoretical nature and cannot provide the necessary details to implement a comprehensive risk evaluation. This paper therefore aims to explore a procedure that allows the inclusion of stakeholders' perceptions of prevention measures in risk assessment. It proposes to adopt methods of risk communication (both one-way and two-way communication) in risk assessment with the final aim of making flood risk management more effective. The proposed procedure not only focuses on the effect of discursive risk communication on risk perception, and on achieving a shared assessment of the prevention alternatives, but also considers the effects of the communication process on perceived uncertainties, accepted risk levels, and trust in the managing institutions. The effectiveness of this combined procedure has been studied and illustrated using the example of the participatory flood prevention assessment process on the Sihl River in Zurich, Switzerland. The main findings of the case study suggest that the proposed procedure performed well, but that it needs some adaptations for it to be applicable in different contexts and to allow a (semi-) quantitative estimation of risk perception to be used as an indicator of adaptive capacity.

The complex model of risk and progression of AMD estimation

Directory of Open Access Journals (Sweden)

V. S. Akopyan

2012-01-01

Full Text Available Purpose: to develop a method and a statistical model to estimate individual risk of AMD and the risk for progression to advanced AMD using clinical and genetic risk factors.Methods: A statistical risk assessment model was developed using stepwise binary logistic regression analysis. to estimate the population differences in the prevalence of allelic variants of genes and for the development of models adapted to the population of Moscow region genotyping and assessment of the influence of other risk factors was performed in two groups: patients with differ- ent stages of AMD (n = 74, and control group (n = 116. Genetic risk factors included in the study: polymorphisms in the complement system genes (C3 and CFH, genes at 10q26 locus (ARMS2 and HtRA1, polymorphism in the mitochondrial gene Mt-ND2. Clinical risk factors included in the study: age, gender, high body mass index, smoking history.Results: A comprehensive analysis of genetic and clinical risk factors for AMD in the study group was performed. Compiled statis- tical model assessment of individual risk of AMD, the sensitivity of the model — 66.7%, specificity — 78.5%, AUC = 0.76. Risk factors of late AMD, compiled a statistical model describing the probability of late AMD, the sensitivity of the model — 66.7%, specificity — 78.3%, AUC = 0.73. the developed system allows determining the most likely version of the current late AMD: dry or wet.Conclusion: the developed test system and the mathematical algorhythm for determining the risk of AMD, risk of progression to advanced AMD have fair diagnostic informative and promising for use in clinical practice.

Urban micro-scale flood risk estimation with parsimonious hydraulic modelling and census data

Directory of Open Access Journals (Sweden)

C. Arrighi

2013-05-01

Full Text Available The adoption of 2007/60/EC Directive requires European countries to implement flood hazard and flood risk maps by the end of 2013. Flood risk is the product of flood hazard, vulnerability and exposure, all three to be estimated with comparable level of accuracy. The route to flood risk assessment is consequently much more than hydraulic modelling of inundation, that is hazard mapping. While hazard maps have already been implemented in many countries, quantitative damage and risk maps are still at a preliminary level. A parsimonious quasi-2-D hydraulic model is here adopted, having many advantages in terms of easy set-up. It is here evaluated as being accurate in flood depth estimation in urban areas with a high-resolution and up-to-date Digital Surface Model (DSM. The accuracy, estimated by comparison with marble-plate records of a historic flood in the city of Florence, is characterized in the downtown's most flooded area by a bias of a very few centimetres and a determination coefficient of 0.73. The average risk is found to be about 14 € m−2 yr−1, corresponding to about 8.3% of residents' income. The spatial distribution of estimated risk highlights a complex interaction between the flood pattern and the building characteristics. As a final example application, the estimated risk values have been used to compare different retrofitting measures. Proceeding through the risk estimation steps, a new micro-scale potential damage assessment method is proposed. This is based on the georeferenced census system as the optimal compromise between spatial detail and open availability of socio-economic data. The results of flood risk assessment at the census section scale resolve most of the risk spatial variability, and they can be easily aggregated to whatever upper scale is needed given that they are geographically defined as contiguous polygons. Damage is calculated through stage–damage curves, starting from census data on building type and

Option-Based Estimation of the Price of Co-Skewness and Co-Kurtosis Risk

DEFF Research Database (Denmark)

Christoffersen, Peter; Fournier, Mathieu; Fournier, Mathieu

-neutral second moments, and the price of co-kurtosis risk corresponds to the spread between the physical and the risk-neutral third moments. The option-based estimates of the prices of risk lead to reasonable values of the associated risk premia. An out-of-sample analysis of factor models with co-skewness and co......We show that the prices of risk for factors that are nonlinear in the market return are readily obtained using index option prices. We apply this insight to the price of co-skewness and co-kurtosis risk. The price of co-skewness risk corresponds to the spread between the physical and the risk......-kurtosis risk indicates that the new estimates of the price of risk improve the models performance. Models with higher-order market moments also robustly outperform standard competitors such as the CAPM and the Fama-French model....

Option-Based Estimation of the Price of Co-Skewness and Co-Kurtosis Risk

DEFF Research Database (Denmark)

Christoffersen, Peter; Fournier, Mathieu; Jacobs, Kris

-neutral second moments, and the price of co-kurtosis risk corresponds to the spread between the physical and the risk-neutral third moments. The option-based estimates of the prices of risk lead to reasonable values of the associated risk premia. An out-of-sample analysis of factor models with co-skewness and co......We show that the prices of risk for factors that are nonlinear in the market return are readily obtained using index option prices. We apply this insight to the price of co-skewness and co-kurtosis risk. The price of co-skewness risk corresponds to the spread between the physical and the risk......-kurtosis risk indicates that the new estimates of the price of risk improve the models' performance. Models with higher-order market moments also robustly outperform standard competitors such as the CAPM and the Fama-French model....

Health effects of low-level ionising radiation: biological basis for risk assessment

International Nuclear Information System (INIS)

Upton, A.C.

1987-01-01

The biological basis for risk assessment is discussed. The risks of carcinogenic effects, teratogenic effects, and genetic (heritable) effects are estimated to vary in proportion with the dose of radiation in the low-dose domain; however, the risks also appear to vary with the LET of the radiation, age at the time of irradiation, and other variables. Although the data suffice to place the risks in perspective with other hazards of modern life, further research to refine the reliability of the risk assessment is called for. (author)

Estimation of Cardiovascular Risk in Patients with Type 2 Diabetes

Directory of Open Access Journals (Sweden)

Belkis Vicente Sánchez

2015-09-01

Full Text Available Background: diabetes mellitus accelerates atherosclerotic changes throughout the vascular tree and consequently increases the risk of developing fatal acute events. Objective: to estimate the global cardiovascular risk in patients with type 2 diabetes mellitus. Method: a cross-sectional study of a series of type 2 diabetic patients from the People's Council of Constancia, Abreus municipality, Cienfuegos province was conducted from July to December 2012. The universe comprised the 180 people with diabetes in the area. Variables studied were: age, sex, body mass index, nutritional assessment, blood pressure, toxic habits, associated chronic diseases, blood levels of glucose, lipids (total cholesterol and triglycerides and microalbuminuria. World Health Organization/International Society of Hypertension prediction charts specific to the region of the Americas, in which Cuba is included, were used to estimate the cardiovascular risk. Results: mean age was 61.63 years and females predominated. Relevant risk factors were hypertension followed by obesity, smoking and dyslipidemia. Mean body mass index was 27.66kg/m2; waist circumference was 94.45 cm in women and 96.86 cm in men. Thirty point six percent had more than two uncontrolled risk factors and 28.3 % of the total presented a high to very high cardiovascular risk. Conclusions: cardiovascular risk prediction charts are helpful tools for making clinical decisions, but their interpretation must be flexible and allow the intervention of clinical reasoning.

The estimation of time-varying risks in asset pricing modelling using B-Spline method

Science.gov (United States)

Nurjannah; Solimun; Rinaldo, Adji

2017-12-01

Asset pricing modelling has been extensively studied in the past few decades to explore the risk-return relationship. The asset pricing literature typically assumed a static risk-return relationship. However, several studies found few anomalies in the asset pricing modelling which captured the presence of the risk instability. The dynamic model is proposed to offer a better model. The main problem highlighted in the dynamic model literature is that the set of conditioning information is unobservable and therefore some assumptions have to be made. Hence, the estimation requires additional assumptions about the dynamics of risk. To overcome this problem, the nonparametric estimators can also be used as an alternative for estimating risk. The flexibility of the nonparametric setting avoids the problem of misspecification derived from selecting a functional form. This paper investigates the estimation of time-varying asset pricing model using B-Spline, as one of nonparametric approach. The advantages of spline method is its computational speed and simplicity, as well as the clarity of controlling curvature directly. The three popular asset pricing models will be investigated namely CAPM (Capital Asset Pricing Model), Fama-French 3-factors model and Carhart 4-factors model. The results suggest that the estimated risks are time-varying and not stable overtime which confirms the risk instability anomaly. The results is more pronounced in Carhart’s 4-factors model.

The effect of bright lines in environmental risk communication

International Nuclear Information System (INIS)

Wilson, K.N.; Desvousges, W.H.; Smith, K.V.; Payne, J.

1993-01-01

Bright lines in environmental risk communication refer to the specific levels at which an environmental risk becomes a serious health threat and action should be taken to mitigate its effects. This study examined the effect of ''bright lines'' in risk communication by emphasizing the radon exposure threshold level of 4 picocuries per liter. Specifically, the authors developed a computer-assisted interview containing bright-line versions of risk information. The bright-line version contained a range of possible radon levels, the corresponding number of estimated lung cancer cases, the relative health risk from radon compared to other health risks, and the EPA guidelines for mitigating levels above 4 picocuries in the home. The non-bright line version was identical to the bright-line version, except it did not include the EPA's mitigation recommendations. Effect measures included respondents' change in perceived risk after reading their materials, intended testing behavior, and advice to their neighbor for a specified radon level either above or below the 4 picocury threshold level. This paper discusses broader policy implications for designing effective risk communication programs

An exploration of spatial risk assessment for soil protection: estimating risk and establishing priority areas for soil protection.

Science.gov (United States)

Kibblewhite, M G; Bellamy, P H; Brewer, T R; Graves, A R; Dawson, C A; Rickson, R J; Truckell, I; Stuart, J

2014-03-01

Methods for the spatial estimation of risk of harm to soil by erosion by water and wind and by soil organic matter decline are explored. Rates of harm are estimated for combinations of soil type and land cover (as a proxy for hazard frequency) and used to estimate risk of soil erosion and loss of soil organic carbon (SOC) for 1 km(2)pixels. Scenarios are proposed for defining the acceptability of risk of harm to soil: the most precautionary one corresponds to no net harm after natural regeneration of soil (i.e. a 1 in 20 chance of exceeding an erosion rate of soils and a carbon stock decline of 0 tha(-1)y(-1) for organic soils). Areas at higher and lower than possible acceptable risk are mapped. The veracity of boundaries is compromised if areas of unacceptable risk are mapped to administrative boundaries. Errors in monitoring change in risk of harm to soil and inadequate information on risk reduction measures' efficacy, at landscape scales, make it impossible to use or monitor quantitative targets for risk reduction adequately. The consequences for priority area definition of expressing varying acceptable risk of harm to soil as a varying probability of exceeding a fixed level of harm, or, a varying level of harm being exceeded with a fixed probability, are discussed. Soil data and predictive models for rates of harm to soil would need considerable development and validation to implement a priority area approach robustly. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of a risk-based online mammography intervention on accuracy of perceived risk and mammography intentions.

Science.gov (United States)

Seitz, Holli H; Gibson, Laura; Skubisz, Christine; Forquer, Heather; Mello, Susan; Schapira, Marilyn M; Armstrong, Katrina; Cappella, Joseph N

2016-10-01

This experiment tested the effects of an individualized risk-based online mammography decision intervention. The intervention employs exemplification theory and the Elaboration Likelihood Model of persuasion to improve the match between breast cancer risk and mammography intentions. 2918 women ages 35-49 were stratified into two levels of 10-year breast cancer risk (<1.5%; ≥1.5%) then randomly assigned to one of eight conditions: two comparison conditions and six risk-based intervention conditions that varied according to a 2 (amount of content: brief vs. extended) x 3 (format: expository vs. untailored exemplar [example case] vs. tailored exemplar) design. Outcomes included mammography intentions and accuracy of perceived breast cancer risk. Risk-based intervention conditions improved the match between objective risk estimates and perceived risk, especially for high-numeracy women with a 10-year breast cancer risk ≤1.5%. For women with a risk≤1.5%, exemplars improved accuracy of perceived risk and all risk-based interventions increased intentions to wait until age 50 to screen. A risk-based mammography intervention improved accuracy of perceived risk and the match between objective risk estimates and mammography intentions. Interventions could be applied in online or clinical settings to help women understand risk and make mammography decisions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Data Sources for the Model-based Small Area Estimates of Cancer Risk Factors and Screening Behaviors - Small Area Estimates

Science.gov (United States)

The model-based estimates of important cancer risk factors and screening behaviors are obtained by combining the responses to the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS).

MCNPX dosimetry and radiation-induced cancer risk estimation from 18F-FDG pediatric PET at Brazilian population

International Nuclear Information System (INIS)

Mendes, Bruno M.; Fonseca, Telma C.F.; Campos, Tarcisio P.R.

2017-01-01

Positron emission tomography (PET) using 18 F-FDG has increased significantly in pediatric patients. PET with 18 F-FDG has often been applied in oncology. Cancer induction is one of the main stochastic risk from exposure to ionizing radiation of 18 F-FDG. Radiation-induced cancer risk estimation due to medical exposures is an important tool for risk/benefit assessing. The objective was to perform dosimetry and estimate the risk of cancer induction due to pediatric use of 18 F-FDG. MCNPX Computational dosimetry was performed to estimate organ absorbed doses resulting from 18 F-FDG pediatric use. Two voxelized phantoms, kindly provided by the GSF - Helmholtz Zentrum, were used: 'Child' - 7 years child and 'Baby' 8-week-old infant. ICRP-128 publication provided the radiopharmaceutical biodistribution of F-18. Tables containing organ absorbed dose and effective dose per unit of injected activity for the two phantoms were obtained. The injected activities were estimated according to data provided in the literature. Images of the absorbed dose distribution were generated from both models. The BEIR VII methodology was used to calculate the risk of cancer induction. The risk of cancer induction (per imaging procedure) for the seven-year-old child was (0.09% ♂ and 0.15% ♀) and for the eight-week old baby was (0.11% ♂ and 0.21% ♀). The 18 F-FDG absorbed dose distribution in the children and infants showed some divergences in comparison to adult data. Probably, the biokinetic data used to children and infants is the main reason for this disconnection. (author)

Estimating the concordance probability in a survival analysis with a discrete number of risk groups.

Science.gov (United States)

Heller, Glenn; Mo, Qianxing

2016-04-01

A clinical risk classification system is an important component of a treatment decision algorithm. A measure used to assess the strength of a risk classification system is discrimination, and when the outcome is survival time, the most commonly applied global measure of discrimination is the concordance probability. The concordance probability represents the pairwise probability of lower patient risk given longer survival time. The c-index and the concordance probability estimate have been used to estimate the concordance probability when patient-specific risk scores are continuous. In the current paper, the concordance probability estimate and an inverse probability censoring weighted c-index are modified to account for discrete risk scores. Simulations are generated to assess the finite sample properties of the concordance probability estimate and the weighted c-index. An application of these measures of discriminatory power to a metastatic prostate cancer risk classification system is examined.

Using mortality data to estimate radiation effects on breast cancer incidence

International Nuclear Information System (INIS)

Hoel, D.G.; Dinse, G.E.

1990-01-01

In this paper we combine Japanese data on radiation exposure and cancer mortality with U.S. data on cancer incidence and lethality to estimate the effects of ionizing radiation on cancer incidence. The analysis is based on the mathematical relationship between the mortality rate and the incidence and lethality rates, as well as on statistical models that relate Japanese incidence rates to U.S. incidence rates and radiation risk factors. Our approach assumes that the risk of death from causes other than the cancer does not depend on whether or not the cancer is present, and among individuals with the cancer, the risk of death attributable to the cancer is the same in Japan and the U.S. and is not affected by radiation exposure. In particular, we focus on the incidence of breast cancer in Japanese women and how this incidence is affected by radiation risk factors. The analysis uses Japanese exposure and mortality data from the Radiation Effects Research Foundation study of atomic bomb survivors and U.S. incidence and lethality data from the Surveillance, Epidemiology, and End Results Registry. Even without Japanese incidence data, we obtain reasonable estimates of the incidence of breast cancer in unexposed Japanese women and identify the radiation risk factors that affect this incidence. Our analysis demonstrates that the age at exposure is an important risk factor, but that the incidence of breast cancer is not affected by the city of residence (Nagasaki versus Hiroshima) or the time since exposure

The Danish fat tax—Effects on consumption patterns and risk of ischaemic heart disease

DEFF Research Database (Denmark)

Bødker, Malene; Pisinger, Charlotta Holm; Toft, Ulla

2015-01-01

sale of the included foodstuffs decreased by 0.9%. The fat tax was associated with marginal changes in population risk of IHD. One estimate suggests an increased population risk of IHD by 0.2% and the other estimate suggests that the risk of IHD decreased by 0.3%. Conclusions: The Danish fat tax had......Objective: To examine the effects on consumption and risk of ischemic heart disease (IHD) of the Danish fat tax, effective from October 2011 to January 2013. Methods: We used comprehensive retail outlet data on the sale of twelve foodstuff categories targeted by the fat tax. Data covered January...

An adaptive spatio-temporal smoothing model for estimating trends and step changes in disease risk

OpenAIRE

Rushworth, Alastair; Lee, Duncan; Sarran, Christophe

2014-01-01

Statistical models used to estimate the spatio-temporal pattern in disease\\ud risk from areal unit data represent the risk surface for each time period with known\\ud covariates and a set of spatially smooth random effects. The latter act as a proxy\\ud for unmeasured spatial confounding, whose spatial structure is often characterised by\\ud a spatially smooth evolution between some pairs of adjacent areal units while other\\ud pairs exhibit large step changes. This spatial heterogeneity is not c...

Consolidating Risk Estimates for Radiation-Induced Complications in Individual Patient: Late Rectal Toxicity

Energy Technology Data Exchange (ETDEWEB)

Prior, Phillip; Devisetty, Kiran [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Tarima, Sergey S. [Division of Biostatistics, Institute for Health and Society, Medical College of Wisconsin, Milwaukee, WI (United States); Lawton, Colleen A.F. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Semenenko, Vladimir A., E-mail: vsemenenko@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

2012-05-01

Purpose: To test the feasibility of a new approach to synthesize published normal tissue complication data using late rectal toxicity in prostate cancer as an example. Methods and Materials: A data survey was performed to identify the published reports on the dose-response relationships for late rectal toxicity. The risk estimates for Grade 1 or greater, Grade 2 or greater, and Grade 3 or greater toxicity were obtained for a test cohort of patients treated at our institution. The influence of the potential factors that might have affected the reported toxicity levels was investigated. The studies that did not conform to the general data trends were excluded, and single, combined risk estimates were derived for each patient and toxicity level. Results: A total of 21 studies of nonoverlapping patient populations were identified. Three studies provided dose-response models for more than one level of toxicity. Of these 21 studies, 6, 14, and 5 were used to derive the initial risk estimates for Grade 1, 2, and 3 or greater toxicity, respectively. A comparison of risk estimates between the studies reporting rectal bleeding and rectal toxicity (bleeding plus other symptoms) or between studies with follow-up <36 months and {>=}36 months did not reveal significant differences (p {>=} .29 for all comparisons). After excluding three reports that did not conform to the general data trends, the combined risk estimates were derived from 5 reports (647 patients), 11 reports (3,369 patients), and 5 reports (1,330 patients) for Grade 1, 2, and 3 or greater toxicity, respectively. Conclusions: The proposed approach is feasible and allows for more systematic use of published dose-response data to estimate the complication risks for the individual patient.

Consolidating Risk Estimates for Radiation-Induced Complications in Individual Patient: Late Rectal Toxicity

International Nuclear Information System (INIS)

Prior, Phillip; Devisetty, Kiran; Tarima, Sergey S.; Lawton, Colleen A.F.; Semenenko, Vladimir A.

2012-01-01

Purpose: To test the feasibility of a new approach to synthesize published normal tissue complication data using late rectal toxicity in prostate cancer as an example. Methods and Materials: A data survey was performed to identify the published reports on the dose–response relationships for late rectal toxicity. The risk estimates for Grade 1 or greater, Grade 2 or greater, and Grade 3 or greater toxicity were obtained for a test cohort of patients treated at our institution. The influence of the potential factors that might have affected the reported toxicity levels was investigated. The studies that did not conform to the general data trends were excluded, and single, combined risk estimates were derived for each patient and toxicity level. Results: A total of 21 studies of nonoverlapping patient populations were identified. Three studies provided dose–response models for more than one level of toxicity. Of these 21 studies, 6, 14, and 5 were used to derive the initial risk estimates for Grade 1, 2, and 3 or greater toxicity, respectively. A comparison of risk estimates between the studies reporting rectal bleeding and rectal toxicity (bleeding plus other symptoms) or between studies with follow-up <36 months and ≥36 months did not reveal significant differences (p ≥ .29 for all comparisons). After excluding three reports that did not conform to the general data trends, the combined risk estimates were derived from 5 reports (647 patients), 11 reports (3,369 patients), and 5 reports (1,330 patients) for Grade 1, 2, and 3 or greater toxicity, respectively. Conclusions: The proposed approach is feasible and allows for more systematic use of published dose–response data to estimate the complication risks for the individual patient.

Methodology for the Model-based Small Area Estimates of Cancer Risk Factors and Screening Behaviors - Small Area Estimates

Science.gov (United States)

This model-based approach uses data from both the Behavioral Risk Factor Surveillance System (BRFSS) and the National Health Interview Survey (NHIS) to produce estimates of the prevalence rates of cancer risk factors and screening behaviors at the state, health service area, and county levels.

Estimating young Australian adults' risk of hearing damage from selected leisure activities.

Science.gov (United States)

Beach, Elizabeth; Williams, Warwick; Gilliver, Megan

2013-01-01

Several previous studies have attempted to estimate the risk of noise-induced hearing loss from loud leisure noise. Some of these studies may have overestimated the risk because they used noise estimates taken from the higher end of reported levels. The aim of the present study was to provide a realistic estimate of the number of young Australian adults who may be at risk of hearing damage and eventual hearing loss from leisure-noise exposure. Average noise levels at five high-noise leisure activities, (1) nightclubs; (2) pubs, bars, and registered clubs; (3) fitness classes; (4) live sporting events; (5) concerts and live music venues, were calculated using 108 measurements taken from a large database of leisure noise measurements. In addition, an online survey was administered to a convenience sample of 1000 young adults aged 18 to 35 years, who reported the time spent at these leisure activities and the frequency with which they undertook the activities. They also answered questions about tinnitus and their perceived risk of hearing damage. Although the survey data cannot be considered representative of the population of young Australian adults, it was weighted to this population in respect of age, gender, education, and location. The survey data and the average noise levels were used to estimate each individual's annual noise exposure, and in turn, estimate those at risk of hearing damage from leisure-noise exposure. For the majority of participants (n = 868), the accumulated leisure noise level was within the acceptable workplace limit. However, 132 participants or 14.1% (population weighted) were exposed to an annual noise dose greater than the acceptable workplace noise limit. By far, the main source of high-risk leisure noise was from nightclubs. Those with more leisure-noise exposure experienced more tinnitus and perceived themselves to be more at risk than those with lower noise exposures. It is recommended that nightclub operators reduce noise levels

Use of BEIR V and UNSCEAR 1988 in radiation risk assessment: Lifetime total cancer mortality risk estimates at low doses and low dose rates for low-LET radiation

International Nuclear Information System (INIS)

1992-12-01

In November 1986, the Department of Defense (DoD) asked the Committee on Interagency Radiation Research and Policy Coordination (CIRRPC) to develop a coordinated Federal position on risk assessment for low levels of ionizing radiation. Since Federal risk assessment activities are based primarily on the scientific data and analyses in authoritative review documents prepared by groups like the National Academy of Sciences' Committee on the Biological Effects of Ionizing Radiation (BEIR), the National Council on Radiation Protection and Measurements (NCRP) and the United Nations' Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), DoD proposed that the CIRRPC Science Panel undertake the task of providing coordinated interagency positions on the use of information in the reports of such groups. The practice has been for individual Federal agencies to interpret and decide independently how to use the information provided in such reports. As a result of its deliberations, the Subpanel recommends two nominal risk estimates for lifetime total cancer mortality following whole-body exposure to low levels of low-LET ionizing radiation, one for the general population and one for the working-age population (see Section II). The recommended risk estimates reflect the general agreement of information in BEIR V and UNSCEAR 1988 for total cancer mortality. The Subpanel's risk estimates and associated statements are intended to meet the needs of the Federal agencies for: (a) values that are current; (b) values that are relevant to the low-dose and low dose-rate ionizing radiation exposures principally encountered in carrying out Federal responsibilities; (c) a statement of the change in the estimates of lifetime total cancer mortality relative to estimates in previous authoritative review documents; and (d) a practical statement on the scientific uncertainty associated with applying the lifetime total cancer mortality values at very low doses

Introduction to cost-effectiveness analysis of risk reduction measures in energy systems

International Nuclear Information System (INIS)

1986-07-01

The aim of this report is to introduce readers to methods of cost-effectiveness analysis and their application in risk reduction, especially in connection with the energy-producing industries. The background to the assessment of risk and the problems in estimating it quantitatively are outlined. The methodology of cost-effectiveness analysis is then described, particular attention being given to the way in which results are derived and the overall use that can be made of them. This is followed by a discussion of quantitative applications and an outline of the methods that may be used to derive estimates both of risk and the cost of reducing it. The use of cost-effectiveness analysis is illustrated in an appendix, which gives as a worked example a case study on the reduction of public risk associated with radioactive releases during normal operation of a PWR. After drawing some general conclusions the report recommends that such analyses should normally be used as an aid to risk management whenever several alternative risk reduction measures are under consideration

Lifetime attributable risk as an alternative to effective dose to describe the risk of cancer for patients in diagnostic and therapeutic nuclear medicine

Science.gov (United States)

Andersson, Martin; Eckerman, Keith; Mattsson, Sören

2017-12-01

The aim of this study is to implement lifetime attributable risk (LAR) predictions of cancer for patients of various age and gender, undergoing diagnostic investigations or treatments in nuclear medicine and to compare the outcome with a population risk estimate using effective dose and the International Commission on Radiological Protection risk coefficients. The radiation induced risk of cancer occurrence (incidence) or death from four nuclear medicine procedures are estimated for both male and female between 0 and 120 years. Estimations of cancer risk are performed using recommended administered activities for two diagnostic (18F-FDG and 99mTc-phosphonate complex) and two therapeutic (131I-iodide and 223Ra-dichloride) radiopharmaceuticals to illustrate the use of cancer risk estimations in nuclear medicine. For 18F-FDG, the cancer incidence for a male of 5, 25, 50 and 75 years at exposure is 0.0021, 0.0010, 0.0008 and 0.0003, respectively. For 99mTc phosphonates complex the corresponding values are 0.000 59, 0.000 34, 0.000 27 and 0.000 13, respectively. For an 131I-iodide treatment with 3.7 GBq and 1% uptake 24 h after administration, the cancer incidence for a male of 25, 50 and 75 years at exposure is 0.041, 0.029 and 0.012, respectively. For 223Ra-dichloride with an administration of 21.9 MBq the cancer incidence for a male of 25, 50 and 75 years is 0.31, 0.21 and 0.09, respectively. The LAR estimations are more suitable in health care situations involving individual patients or specific groups of patients than the health detriment based on effective dose, which represents a population average. The detriment consideration in effective dose adjusts the cancer incidence for suffering of non-lethal cancers while LAR predicts morbidity (incidence) or mortality (cancer). The advantages of these LARs are that they are gender and age specific, allowing risk estimations for specific patients or subgroups thus better representing individuals in health care

Cancer risk estimation for mixtures of coal tars and benzo(a)pyrene

International Nuclear Information System (INIS)

Gaylor, D.W.; Culp, S.J.; Goldstein, L.S.; Beland, F.A.

2000-01-01

Two-year chronic bioassays were conducted by using B6C3F1 female mice fed several concentrations of two different mixtures of coal tars from manufactured gas waste sites or benzo(a)pyrene (BaP). The purpose of the study was to obtain estimates of cancer potency of coal tar mixtures, by using conventional regulatory methods, for use in manufactured gas waste site remediation. A secondary purpose was to investigate the validity of using the concentration of a single potent carcinogen, in this case benzo(a)pyrene, to estimate the relative risk for a coal tar mixture. The study has shown that BaP dominates the cancer risk when its concentration is greater than 6,300 ppm in the coal tar mixture. In this case the most sensitive tissue site is the forestomach. Using low-dose linear extrapolation, the lifetime cancer risk for humans is estimated to be: Risk -4 (ppm coal tar in total diet) + 240 x 10 -4 (ppm BaP in total diet), based on forestomach tumors. If the BaP concentration in the coal tar mixture is less than 6,300 ppm, the more likely case, then lung tumors provide the largest estimated upper limit of risk, Risk -4 (ppm coal tar in total diet), with no contribution of BaP to lung tumors. The upper limit of the cancer potency (slope factor) for lifetime oral exposure to benzo(a)pyrene is 1.2 x 10 -3 per microg per kg body weight per day from this Good Laboratory Practice (GLP) study compared with the current value of 7.3 x 10 -3 per microg per kg body weight per day listed in the US EPA Integrated Risk Information System

A-BOMB SURVIVOR SITE-SPECIFIC RADIOGENIC CANCER RISKS ESTIMATES

Science.gov (United States)

A draft manuscript is being prepared that describes ways to improve estimates of risk from radiation that have been derived from A-bomb survivors. The work has been published in the journal Radiation Research volume 169, pages 87-98.

Life cycle cost and risk estimation of environmental management options

International Nuclear Information System (INIS)

Shropshire, D.; Sherick, M.

1996-01-01

The evaluation process is demonstrated in this paper through comparative analysis of two alternative scenarios identified for the management of the alpha-contaminated fixed low-level waste currently stored at INEL. These two scenarios, the Base Case and the Delay Case, are realistic and based on actual data, but are not intended to exactly match actual plans currently being developed at INEL. Life cycle cost estimates were developed for both scenarios using the System Cost Model; resulting costs are presented and compared. Life cycle costs are shown as a function of time and also aggregated by pretreatment, treatment, storage, and disposal activities. Although there are some short-term cost savings for the Delay Case, cumulative life cycle costs eventually become much higher than costs for the Base Case over the same period of time, due mainly to the storage and repackaging necessary to accommodate the longer Delay Case schedule. Life cycle risk estimates were prepared using a new risk analysis method adapted to the System Cost Model architecture for automated, systematic cost/risk applications. Relative risk summaries are presented for both scenarios as a function of time and also aggregated by pretreatment, treatment, storage, and disposal activities. Relative risk of the Delay Case is shown to be higher than that of the Base Case. Finally, risk and cost results are combined to show how the collective information can be used to help identify opportunities for risk or cost reduction and highlight areas where risk reduction can be achieved most economically

Estimating the effect of lay knowledge and prior contact with pulmonary TB patients, on health-belief model in a high-risk pulmonary TB transmission population.

Science.gov (United States)

Zein, Rizqy Amelia; Suhariadi, Fendy; Hendriani, Wiwin

2017-01-01

The research aimed to investigate the effect of lay knowledge of pulmonary tuberculosis (TB) and prior contact with pulmonary TB patients on a health-belief model (HBM) as well as to identify the social determinants that affect lay knowledge. Survey research design was conducted, where participants were required to fill in a questionnaire, which measured HBM and lay knowledge of pulmonary TB. Research participants were 500 residents of Semampir, Asemrowo, Bubutan, Pabean Cantian, and Simokerto districts, where the risk of pulmonary TB transmission is higher than other districts in Surabaya. Being a female, older in age, and having prior contact with pulmonary TB patients significantly increase the likelihood of having a higher level of lay knowledge. Lay knowledge is a substantial determinant to estimate belief in the effectiveness of health behavior and personal health threat. Prior contact with pulmonary TB patients is able to explain the belief in the effectiveness of a health behavior, yet fails to estimate participants' belief in the personal health threat. Health authorities should prioritize males and young people as their main target groups in a pulmonary TB awareness campaign. The campaign should be able to reconstruct people's misconception about pulmonary TB, thereby bringing around the health-risk perception so that it is not solely focused on improving lay knowledge.

Model dependencies of risk aversion and working interest estimates

International Nuclear Information System (INIS)

Lerche, I.

1996-01-01

Working interest, W, and risk adjusted value, RAV, are evaluated using both Cozzolino's formula for exponential dependence of risk aversion and also for a hyperbolic tangent dependence. In addition, the general method is given of constructing an RAV formula for any functional choice of risk aversion dependence. Two examples are given to illustrate how the model dependencies influence choices of working interest and risk adjusted value depending on whether the expected value of the project is positive or negative. In general the Cozzolino formula provides a more conservative position for risk than does the hyperbolic tangent formula, reflecting the difference in corporate attitudes to risk aversion. The commonly used Cozzolino formula is shown to have simple exact arithmetic expressions for maximum working interest and maximum RAV; the hyperbolic tangent formula has approximate analytic expressions. Both formulae also yield approximate analytical expressions for the working interest yielding a risk neutral RAV of zero. These arithmetic results are useful for making quick estimates of working interest ranges and risk adjusted values. (Author)

Radiobiology in clinical radiation therapy: Long term risks - Carcinogenic, hereditary, and teratogenetic effects

International Nuclear Information System (INIS)

Brenner, David J.

1997-01-01

The long-term risks induced by radiation are of much concern to patients and clinicians alike. As an example, perceived radiation risks are frequently cited in a woman's decision to choose a radical mastectomy over lumpectomy + radiation. In consequence, the actual radiation risks are often considerably overstated, or unreasonably downplayed. In this lecture we will discuss just what is known about the long term risks following radiotherapy, both from the human experience and from the laboratory. We will discuss risks both to the patient and to radiotherapy personnel. A good deal is known about the carcinogenic effects of high and low doses of radiation, in large part thanks to the careful study of the survivors of the atomic bombing in Japan, as well as studies of individuals exposed to medical x rays. It is possible to make an estimate, which is probably good to within a factor of, perhaps, three to five, of the cancer risks faced by a patient of a particular age and sex who is going to undergo a particular radiotherapeutic regimen. It is also possible to make an estimate of the risks faced by radiotherapy and nursing staff exposed to low doses. Brachytherapy related risk estimates are likely to be somewhat more uncertain, due to the poorly known sparing effects of the low dose rates used; for the radiotherapy personnel in brachytherapy, because of the doses which can be received, the risks can be quite significant. A recent complication in external-beam radiotherapy is the advent of high-energy linacs, which can produce a significant fast neutron dose which, dose for dose, may be ten to fifty times more carcinogenic than gamma rays. Data relating to the risks of hereditary effects of radiation come almost entirely from laboratory experiments in animals. Studies involving several million mice form the basis of most of our current understanding of hereditary effects. The results of these studies indicate that radiation is a relatively inefficient mutagen. The

Theoretical epidemiology applied to health physics: estimation of the risk of radiation-induced breast cancer

International Nuclear Information System (INIS)

Sutherland, J.V.

1983-01-01

Indirect estimation of low-dose radiation hazards is possible using the multihit model of carcinogenesis. This model is based on cancer incidence data collected over many decades on tens of millions of people. Available data on human radiation effects can be introduced into the modeling process without the requirement that these data precisely define the model to be used. This reduction in the information demanded from the limited data on human radiation effects allows a more rational approach to estimation of low-dose radiation hazards and helps to focus attention on research directed towards understanding the process of carcinogenesis, rather than on repeating human or animal experiments that cannot provide sufficient data to resolve the low-dose estimation problem. Assessment of the risk of radiation-induced breast cancer provides an excellent example of the utility of multihit modeling procedures

Radiation exposure to examiners and patients during therapeutic ERCP: Dose optimisation and risk estimation

International Nuclear Information System (INIS)

Sulieman, A.; Kappas, K.; Theodorou, K.; Paroutoglou, G.; Kapatenakis, A.; Kapsoritakis, A.; Potamianos, S.; Vlychou, M.; Fezoulidis, I.

2008-01-01

Aim: This study intended to optimise the radiation dose during therapeutic ERCP, and to estimate the risk for examiners and patients, to compare the doses based on available data obtained by other researchers and reference levels recommended by international organizations, and to evaluate the technique applied in order to reduce patient and examiners doses. Materials and Methods: 153 patients were studied in two Gastroenterology Departments, (group A, 111; group B, 42). Thermoluminescent dosimeters (TLD) were used to measure the staff and patients entrance surface dose (ESD) at different body sites. Results: The mean ESD, exit and thyroid surface dose per procedure was estimated to be 68.75 mGy, 3.45 mGy and 0.67 mGy, respectively. The mean patient effective dose was 3.44 mSv, and the cancer risk per procedure was estimated to be 190 x10 -6 . The effective dose for the first, second and third examiner was 0.4 μSv, 0.2 μSv and 5.0 μSv, respectively. Conclusion: The patient dose can be optimized by the presence of two experienced examiners and reduction of radiographic images. The examiners should use a wrap around lead apron since the highest dose originating from the X-ray tube, is incident on their side and back. The current formulae, which exist, underestimate the effective dose to the examiners, when they are applied for ERCP procedures. For both patients and examiners, our results were up to 60% lower compared to the lowest values found in previous studies. (authors)

Decline in estimated glomerular filtration rate and subsequent risk of end-stage renal disease and mortality.

Science.gov (United States)

Coresh, Josef; Turin, Tanvir Chowdhury; Matsushita, Kunihiro; Sang, Yingying; Ballew, Shoshana H; Appel, Lawrence J; Arima, Hisatomi; Chadban, Steven J; Cirillo, Massimo; Djurdjev, Ognjenka; Green, Jamie A; Heine, Gunnar H; Inker, Lesley A; Irie, Fujiko; Ishani, Areef; Ix, Joachim H; Kovesdy, Csaba P; Marks, Angharad; Ohkubo, Takayoshi; Shalev, Varda; Shankar, Anoop; Wen, Chi Pang; de Jong, Paul E; Iseki, Kunitoshi; Stengel, Benedicte; Gansevoort, Ron T; Levey, Andrew S

2014-06-25

The established chronic kidney disease (CKD) progression end point of end-stage renal disease (ESRD) or a doubling of serum creatinine concentration (corresponding to a change in estimated glomerular filtration rate [GFR] of −57% or greater) is a late event. To characterize the association of decline in estimated GFR with subsequent progression to ESRD with implications for using lesser declines in estimated GFR as potential alternative end points for CKD progression. Because most people with CKD die before reaching ESRD, mortality risk also was investigated. Individual meta-analysis of 1.7 million participants with 12,344 ESRD events and 223,944 deaths from 35 cohorts in the CKD Prognosis Consortium with a repeated measure of serum creatinine concentration over 1 to 3 years and outcome data. Transfer of individual participant data or standardized analysis of outputs for random-effects meta-analysis conducted between July 2012 and September 2013, with baseline estimated GFR values collected from 1975 through 2012. End-stage renal disease (initiation of dialysis or transplantation) or all-cause mortality risk related to percentage change in estimated GFR over 2 years, adjusted for potential confounders and first estimated GFR. The adjusted hazard ratios (HRs) of ESRD and mortality were higher with larger estimated GFR decline. Among participants with baseline estimated GFR of less than 60 mL/min/1.73 m2, the adjusted HRs for ESRD were 32.1 (95% CI, 22.3-46.3) for changes of −57% in estimated GFR and 5.4 (95% CI, 4.5-6.4) for changes of −30%. However, changes of −30% or greater (6.9% [95% CI, 6.4%-7.4%] of the entire consortium) were more common than changes of −57% (0.79% [95% CI, 0.52%-1.06%]). This association was strong and consistent across the length of the baseline period (1 to 3 years), baseline estimated GFR, age, diabetes status, or albuminuria. Average adjusted 10-year risk of ESRD (in patients with a baseline estimated GFR of 35 mL/min/1.73 m2

Risk Estimation Modeling and Feasibility Testing for a Mobile eHealth Intervention for Binge Drinking Among Young People: The D-ARIANNA (Digital-Alcohol RIsk Alertness Notifying Network for Adolescents and young adults) Project.

Science.gov (United States)

Carrà, Giuseppe; Crocamo, Cristina; Schivalocchi, Alessandro; Bartoli, Francesco; Carretta, Daniele; Brambilla, Giulia; Clerici, Massimo

2015-01-01

Binge drinking is common among young people but often relevant risk factors are not recognized. eHealth apps, attractive for young people, may be useful to enhance awareness of this problem. We aimed at developing a current risk estimation model for binge drinking, incorporated into an eHealth app--D-ARIANNA (Digital-Alcohol RIsk Alertness Notifying Network for Adolescents and young adults)--for young people. A longitudinal approach with phase 1 (risk estimation), phase 2 (design), and phase 3 (feasibility) was followed. Risk/protective factors identified from the literature were used to develop a current risk estimation model for binge drinking. Relevant odds ratios were subsequently pooled through meta-analytic techniques with a random-effects model, deriving weighted estimates to be introduced in a final model. A set of questions, matching identified risk factors, were nested in a questionnaire and assessed for wording, content, and acceptability in focus groups involving 110 adolescents and young adults. Ten risk factors (5 modifiable) and 2 protective factors showed significant associations with binge drinking and were included in the model. Their weighted coefficients ranged between -0.71 (school proficiency) and 1.90 (cannabis use). The model, nested in an eHealth app questionnaire, provides in percent an overall current risk score, accompanied by appropriate images. Factors that mostly contribute are shown in summary messages. Minor changes have been realized after focus groups review. Most of the subjects (74%) regarded the eHealth app as helpful to assess binge drinking risk. We could produce an evidence-based eHealth app for young people, evaluating current risk for binge drinking. Its effectiveness will be tested in a large trial.

Instrumental variable estimation of the causal effect of plasma 25-hydroxy-vitamin D on colorectal cancer risk: a mendelian randomization analysis.

Directory of Open Access Journals (Sweden)

Evropi Theodoratou

Full Text Available Vitamin D deficiency has been associated with several common diseases, including cancer and is being investigated as a possible risk factor for these conditions. We reported the striking prevalence of vitamin D deficiency in Scotland. Previous epidemiological studies have reported an association between low dietary vitamin D and colorectal cancer (CRC. Using a case-control study design, we tested the association between plasma 25-hydroxy-vitamin D (25-OHD and CRC (2,001 cases, 2,237 controls. To determine whether plasma 25-OHD levels are causally linked to CRC risk, we applied the control function instrumental variable (IV method of the mendelian randomization (MR approach using four single nucleotide polymorphisms (rs2282679, rs12785878, rs10741657, rs6013897 previously shown to be associated with plasma 25-OHD. Low plasma 25-OHD levels were associated with CRC risk in the crude model (odds ratio (OR: 0.76, 95% Confidence Interval (CI: 0.71, 0.81, p: 1.4×10(-14 and after adjusting for age, sex and other confounding factors. Using an allele score that combined all four SNPs as the IV, the estimated causal effect was OR 1.16 (95% CI 0.60, 2.23, whilst it was 0.94 (95% CI 0.46, 1.91 and 0.93 (0.53, 1.63 when using an upstream (rs12785878, rs10741657 and a downstream allele score (rs2282679, rs6013897, respectively. 25-OHD levels were inversely associated with CRC risk, in agreement with recent meta-analyses. The fact that this finding was not replicated when the MR approach was employed might be due to weak instruments, giving low power to demonstrate an effect (<0.35. The prevalence and degree of vitamin D deficiency amongst individuals living in northerly latitudes is of considerable importance because of its relationship to disease. To elucidate the effect of vitamin D on CRC cancer risk, additional large studies of vitamin D and CRC risk are required and/or the application of alternative methods that are less sensitive to weak instrument

Time-Dependent Risk Estimation and Cost-Benefit Analysis for Mitigation Actions

Science.gov (United States)

van Stiphout, T.; Wiemer, S.; Marzocchi, W.

2009-04-01

Earthquakes strongly cluster in space and time. Consequently, the most dangerous time is right after a moderate earthquake has happened, because their is a ‘high' (i.e., 2-5 percent) probability that this event will be followed by a subsequent aftershock which happens to be as large or larger than the initiating event. The seismic hazard during this time-period exceeds the background probability significantly and by several orders of magnitude. Scientists have developed increasingly accurate forecast models that model this time-dependent hazard, and such models are currently being validated in prospective testing. However, this probabilistic information in the hazard space is difficult to digest for decision makers, the media and general public. Here, we introduce a possible bridge between seismology and decision makers (authorities, civil defense) by proposing a more objective way to estimate time-dependent risk assessment. Short Term Earthquake Risk assessment (STEER) combines aftershock hazard and loss assessments. We use site-specific information on site effects and building class distribution and combine this with existing loss models to compute site specific time-dependent risk curves (probability of exceedance for fatalities, injuries, damages etc). We show the effect of uncertainties in the different components using Monte Carlo Simulations of the input parameters. This time-dependent risk curves can act as a decision support. We extend the STEER approach by introducing a Cost-Benefit approach for certain mitigation actions after a medium-sized earthquake. Such Cost-Benefit approaches have been recently developed for volcanic risk assessment to rationalize precautionary evacuations in densely inhabitated areas threatened by volcanoes. Here we extend the concept to time-dependent probabilistic seismic risk assessment. For the Cost-Benefit analysis of mitigation actions we calculate the ratio between the cost for the mitigation actions and the cost of the

The Effects of Vehicle Redesign on the Risk of Driver Death.

Science.gov (United States)

Farmer, Charles M; Lund, Adrian K

2015-01-01

This study updates a 2006 report that estimated the historical effects of vehicle design changes on driver fatality rates in the United States, separate from the effects of environmental and driver behavior changes during the same period. In addition to extending the period covered by 8 years, this study estimated the effect of design changes by model year and vehicle type. Driver death rates for consecutive model years of vehicle models without design changes were used to estimate the vehicle aging effect and the death rates that would have been expected if the entire fleet had remained unchanged from the 1985 calendar year. These calendar year estimates are taken to be the combined effect of road environment and motorist behavioral changes, with the difference between them and the actual calendar year driver fatality rates reflecting the effect of changes in vehicle design and distribution of vehicle types. The effects of vehicle design changes by model year were estimated for cars, SUVs, and pickups by computing driver death rates for model years 1984-2009 during each of their first 3 full calendar years of exposure and comparing with the expected rates if there had been no design changes. As reported in the 2006 study, had there been no changes in the vehicle fleet, driver death risk would have declined during calendar years 1985-1993 and then slowly increased from 1993 to 2004. The updated results indicate that the gradual increase would have continued through 2006, after which driver fatality rates again would have declined through 2012. Overall, it is estimated that there were 7,700 fewer driver deaths in 2012 than there would have been had vehicle designs not changed. Cars were the first vehicle type whose design safety generally exceeded that of the 1984 model year (starting in model year 1996), followed by SUVs (1998 models) and pickups (2002 models). By the 2009 model year, car driver fatality risk had declined 51% from its high in 1994, pickup driver

The Cost-Effectiveness of Antibiotic Prophylaxis for Patients at Risk of Infective Endocarditis.

Science.gov (United States)

Franklin, Matthew; Wailoo, Allan; Dayer, Mark J; Jones, Simon; Prendergast, Bernard; Baddour, Larry M; Lockhart, Peter B; Thornhill, Martin H

2016-11-15

In March 2008, the National Institute for Health and Care Excellence recommended stopping antibiotic prophylaxis (AP) for those at risk of infective endocarditis (IE) undergoing dental procedures in the United Kingdom, citing a lack of evidence of efficacy and cost-effectiveness. We have performed a new economic evaluation of AP on the basis of contemporary estimates of efficacy, adverse events, and resource implications. A decision analytic cost-effectiveness model was used. Health service costs and benefits (measured as quality-adjusted life-years) were estimated. Rates of IE before and after the National Institute for Health and Care Excellence guidance were available to estimate prophylactic efficacy. AP adverse event rates were derived from recent UK data, and resource implications were based on English Hospital Episode Statistics. AP was less costly and more effective than no AP for all patients at risk of IE. The results are sensitive to AP efficacy, but efficacy would have to be substantially lower for AP not to be cost-effective. AP was even more cost-effective in patients at high risk of IE. Only a marginal reduction in annual IE rates (1.44 cases in high-risk and 33 cases in all at-risk patients) would be required for AP to be considered cost-effective at £20 000 ($26 600) per quality-adjusted life-year. Annual cost savings of £5.5 to £8.2 million ($7.3-$10.9 million) and health gains >2600 quality-adjusted life-years could be achieved from reinstating AP in England. AP is cost-effective for preventing IE, particularly in those at high risk. These findings support the cost-effectiveness of guidelines recommending AP use in high-risk individuals. © 2016 The Authors.

Comparative estimates of risks arising from storage of intermediate level radioactive wastes

International Nuclear Information System (INIS)

Moore, D.

1986-04-01

Estimates are presented of risks arising from accidents occuring during storage of nine types of conditioned intermediate level waste. Additional data are introduced relating to the risks from accidents affecting raw waste, and to risks associated with the occupational doses received during normal operation of a waste store. Risks in all three categories are shown to be extremely small. (author)

Uncertainties in fatal cancer risk estimates used in radiation protection

International Nuclear Information System (INIS)

Kai, Michiaki

1999-01-01

Although ICRP and NCRP had not described the details of uncertainties in cancer risk estimates in radiation protection, NCRP, in 1997, firstly reported the results of uncertainty analysis (NCRP No.126) and which is summarized in this paper. The NCRP report pointed out that there are following five factors which uncertainty possessing: uncertainty in epidemiological studies, in dose assessment, in transforming the estimates to risk assessment, in risk prediction and in extrapolation to the low dose/dose rate. These individual factors were analyzed statistically to obtain the relationship between the probability of cancer death in the US population and life time risk coefficient (% per Sv), which showed that, for the latter, the mean value was 3.99 x 10 -2 /Sv, median, 3.38 x 10 -2 /Sv, GSD (geometrical standard deviation), 1.83 x 10 -2 /Sv and 95% confidential limit, 1.2-8.84 x 10 -2 /Sv. The mean value was smaller than that of ICRP recommendation (5 x 10 -2 /Sv), indicating that the value has the uncertainty factor of 2.5-3. Moreover, the most important factor was shown to be the uncertainty in DDREF (dose/dose rate reduction factor). (K.H.)

Effects of exposure estimation errors on estimated exposure-response relations for PM2.5.

Science.gov (United States)

Cox, Louis Anthony Tony

2018-07-01

Associations between fine particulate matter (PM2.5) exposure concentrations and a wide variety of undesirable outcomes, from autism and auto theft to elderly mortality, suicide, and violent crime, have been widely reported. Influential articles have argued that reducing National Ambient Air Quality Standards for PM2.5 is desirable to reduce these outcomes. Yet, other studies have found that reducing black smoke and other particulate matter by as much as 70% and dozens of micrograms per cubic meter has not detectably affected all-cause mortality rates even after decades, despite strong, statistically significant positive exposure concentration-response (C-R) associations between them. This paper examines whether this disconnect between association and causation might be explained in part by ignored estimation errors in estimated exposure concentrations. We use EPA air quality monitor data from the Los Angeles area of California to examine the shapes of estimated C-R functions for PM2.5 when the true C-R functions are assumed to be step functions with well-defined response thresholds. The estimated C-R functions mistakenly show risk as smoothly increasing with concentrations even well below the response thresholds, thus incorrectly predicting substantial risk reductions from reductions in concentrations that do not affect health risks. We conclude that ignored estimation errors obscure the shapes of true C-R functions, including possible thresholds, possibly leading to unrealistic predictions of the changes in risk caused by changing exposures. Instead of estimating improvements in public health per unit reduction (e.g., per 10 µg/m 3 decrease) in average PM2.5 concentrations, it may be essential to consider how interventions change the distributions of exposure concentrations. Copyright © 2018 Elsevier Inc. All rights reserved.

Geostatistical risk estimation at waste disposal sites in the presence of hot spots

International Nuclear Information System (INIS)

Komnitsas, Kostas; Modis, Kostas

2009-01-01

The present paper aims to estimate risk by using geostatistics at the wider coal mining/waste disposal site of Belkovskaya, Tula region, in Russia. In this area the presence of hot spots causes a spatial trend in the mean value of the random field and a non-Gaussian data distribution. Prior to application of geostatistics, subtraction of trend and appropriate smoothing and transformation of the data into a Gaussian form were carried out; risk maps were then generated for the wider study area in order to assess the probability of exceeding risk thresholds. Finally, the present paper discusses the need for homogenization of soil risk thresholds regarding hazardous elements that will enhance reliability of risk estimation and enable application of appropriate rehabilitation actions in contaminated areas.

Assessing the risk of Legionnaires' disease: the inhalation exposure model and the estimated risk in residential bathrooms.

Science.gov (United States)

Azuma, Kenichi; Uchiyama, Iwao; Okumura, Jiro

2013-02-01

Legionella are widely found in the built environment. Patients with Legionnaires' disease have been increasing in Japan; however, health risks from Legionella bacteria in the environment are not appropriately assessed. We performed a quantitative health risk assessment modeled on residential bathrooms in the Adachi outbreak area and estimated risk levels. The estimated risks in the Adachi outbreak approximately corresponded to the risk levels exponentially extrapolated into lower levels on the basis of infection and mortality rates calculated from actual outbreaks, suggesting that the model of Legionnaires' disease in residential bathrooms was adequate to predict disease risk for the evaluated outbreaks. Based on this model, the infection and mortality risk levels per year in 10 CFU/100 ml (100 CFU/L) of the Japanese water quality guideline value were approximately 10(-2) and 10(-5), respectively. However, acceptable risk levels of infection and mortality from Legionnaires' disease should be adjusted to approximately 10(-4) and 10(-7), respectively, per year. Therefore, a reference value of 0.1 CFU/100 ml (1 CFU/L) as a water quality guideline for Legionella bacteria is recommended. This value is occasionally less than the actual detection limit. Legionella levels in water system should be maintained as low as reasonably achievable (<1 CFU/L). Copyright © 2012 Elsevier Inc. All rights reserved.

Combined methodology for estimating dose rates and health effects from exposure to radioactive pollutants

Energy Technology Data Exchange (ETDEWEB)

Dunning, D.E. Jr.; Leggett, R.W.; Yalcintas, M.G.

1980-12-01

The work described in the report is basically a synthesis of two previously existing computer codes: INREM II, developed at the Oak Ridge National Laboratory (ORNL); and CAIRD, developed by the Environmental Protection Agency (EPA). The INREM II code uses contemporary dosimetric methods to estimate doses to specified reference organs due to inhalation or ingestion of a radionuclide. The CAIRD code employs actuarial life tables to account for competing risks in estimating numbers of health effects resulting from exposure of a cohort to some incremental risk. The combined computer code, referred to as RADRISK, estimates numbers of health effects in a hypothetical cohort of 100,000 persons due to continuous lifetime inhalation or ingestion of a radionuclide. Also briefly discussed in this report is a method of estimating numbers of health effects in a hypothetical cohort due to continuous lifetime exposure to external radiation. This method employs the CAIRD methodology together with dose conversion factors generated by the computer code DOSFACTER, developed at ORNL; these dose conversion factors are used to estimate dose rates to persons due to radionuclides in the air or on the ground surface. The combination of the life table and dosimetric guidelines for the release of radioactive pollutants to the atmosphere, as required by the Clean Air Act Amendments of 1977.

The impact of involved node, involved field and mantle field radiotherapy on estimated radiation doses and risk of late effects for pediatric patients with Hodgkin lymphoma

DEFF Research Database (Denmark)

Maraldo, M. V.; Jorgensen, M.; Brodin, N. P.

2014-01-01

–II classical HL patients 4 x 2 plans for each patient. The lifetime excess risks of cardiac morbidity, cardiac mortality, lung, breast, and thyroid cancer with each technique were estimated. The estimated excess risks attributable to RT were based on HL series with long-term follow......IFRT), and Involved Node RT (INRT) and the risk of radiation-induced cardiovascular disease, secondary cancers, and the corresponding Life Years Lost (LYL) is estimated with each technique. PROCEDURE: INRT, mIFRT, IFRT, and MF plans (20 and 30 Gy) were simulated for 10 supradiaphragmatic, clinical stage I...... to the heart, lungs, breasts, and thyroid compared to past,extended fields, even for patients with mediastinal disease. This translated into a significantly reduced estimated risk of cardiovascular disease, secondary cancers, and LYL. CONCLUSIONS: Involved Node Radiotherapy should be considered for pediatric...

Estimating the cost-effectiveness of stroke units in France compared with conventional care.

Science.gov (United States)

Launois, R; Giroud, M; Mégnigbêto, A C; Le Lay, K; Présenté, G; Mahagne, M H; Durand, I; Gaudin, A F

2004-03-01

The incidence of stroke in France is estimated at between 120 000 and 150 000 cases per year. This modeling study assessed the clinical and economic benefits of establishing specialized stroke units compared with conventional care. Data from the Dijon stroke registry were used to determine healthcare trajectories according to the degree of autonomy and organization of patient care. The relative risks of death or institutionalization or death or dependence after passage through a stroke unit were compared with conventional care. These risks were then inserted with the costing data into a Markov model to estimate the cost-effectiveness of stroke units. Patients cared for in a stroke unit survive more trimesters without sequelae in the 5 years after hospitalization than those cared for conventionally (11.6 versus 8.28 trimesters). The mean cost per patient at 5 years was estimated at 30 983 for conventional care and 34 638 in a stroke unit. An incremental cost-effectiveness ratio for stroke units of 1359 per year of life gained without disability was estimated. The cost-effectiveness ratio for stroke units is much lower than the threshold (53 400 ) of acceptability recognized by the international scientific community. This finding justifies organizational changes in the management of stroke patients and the establishment of stroke units in France.

Sensitivity Analysis of Median Lifetime on Radiation Risks Estimates for Cancer and Circulatory Disease amongst Never-Smokers

Science.gov (United States)

Chappell, Lori J.; Cucinotta, Francis A.

2011-01-01

Radiation risks are estimated in a competing risk formalism where age or time after exposure estimates of increased risks for cancer and circulatory diseases are folded with a probability to survive to a given age. The survival function, also called the life-table, changes with calendar year, gender, smoking status and other demographic variables. An outstanding problem in risk estimation is the method of risk transfer between exposed populations and a second population where risks are to be estimated. Approaches used to transfer risks are based on: 1) Multiplicative risk transfer models -proportional to background disease rates. 2) Additive risk transfer model -risks independent of background rates. In addition, a Mixture model is often considered where the multiplicative and additive transfer assumptions are given weighted contributions. We studied the influence of the survival probability on the risk of exposure induced cancer and circulatory disease morbidity and mortality in the Multiplicative transfer model and the Mixture model. Risks for never-smokers (NS) compared to the average U.S. population are estimated to be reduced between 30% and 60% dependent on model assumptions. Lung cancer is the major contributor to the reduction for NS, with additional contributions from circulatory diseases and cancers of the stomach, liver, bladder, oral cavity, esophagus, colon, a portion of the solid cancer remainder, and leukemia. Greater improvements in risk estimates for NS s are possible, and would be dependent on improved understanding of risk transfer models, and elucidating the role of space radiation on the various stages of disease formation (e.g. initiation, promotion, and progression).

Stroke risk estimation across nine European countries in the MORGAM project

DEFF Research Database (Denmark)

Borglykke, Anders; Andreasen, Anne H; Kuulasmaa, Kari

2010-01-01

Previous tools for stroke risk assessment have either been developed for specific populations or lack data on non-fatal events or uniform data collection. The purpose of this study was to develop a stepwise model for the estimation of 10 year risk of stroke in nine different countries across Europe....

Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model.

Science.gov (United States)

Tang, Jiechen; Zhou, Chao; Yuan, Xinyu; Sriboonchitta, Songsak

2015-01-01

This paper concentrates on estimating the risk of Title Transfer Facility (TTF) Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT) is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR) and conditional value at risk (CVaR). Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

Estimating Risk of Natural Gas Portfolios by Using GARCH-EVT-Copula Model

Directory of Open Access Journals (Sweden)

Jiechen Tang

2015-01-01

Full Text Available This paper concentrates on estimating the risk of Title Transfer Facility (TTF Hub natural gas portfolios by using the GARCH-EVT-copula model. We first use the univariate ARMA-GARCH model to model each natural gas return series. Second, the extreme value distribution (EVT is fitted to the tails of the residuals to model marginal residual distributions. Third, multivariate Gaussian copula and Student t-copula are employed to describe the natural gas portfolio risk dependence structure. Finally, we simulate N portfolios and estimate value at risk (VaR and conditional value at risk (CVaR. Our empirical results show that, for an equally weighted portfolio of five natural gases, the VaR and CVaR values obtained from the Student t-copula are larger than those obtained from the Gaussian copula. Moreover, when minimizing the portfolio risk, the optimal natural gas portfolio weights are found to be similar across the multivariate Gaussian copula and Student t-copula and different confidence levels.

Association between subjective risk perception and objective risk estimation in patients with atrial fibrillation: a cross-sectional study.

Science.gov (United States)

Zweiker, David; Zweiker, Robert; Winkler, Elisabeth; Roesch, Konstantina; Schumacher, Martin; Stepan, Vinzenz; Krippl, Peter; Bauer, Norbert; Heine, Martin; Reicht, Gerhard; Zweiker, Gudrun; Sprenger, Martin; Watzinger, Norbert

2017-09-25

Oral anticoagulation (OAC) is state-of-the-art therapy for atrial fibrillation (AF), the most common arrhythmia worldwide. However, little is known about the perception of patients with AF and how it correlates with risk scores used by their physicians. Therefore, we correlated patients' estimates of their own stroke and bleeding risk with the objectively predicted individual risk using CHA 2 DS 2 -VASc and HAS-BLED scores. Cross-sectional prevalence study using convenience sampling and telephone follow-up. Eight hospital departments and one general practitioner in Austria. Patients' perception of stroke and bleeding risk was opposed to commonly used risk scoring. Patients with newly diagnosed AF and indication for anticoagulation. Comparison of subjective risk perception with CHA 2 DS 2 -VASc and HAS-BLED scores showing possible discrepancies between subjective and objective risk estimation. Patients' judgement of their own knowledge on AF and education were also correlated with accuracy of subjective risk appraisal. Ninety-one patients (age 73±11 years, 45% female) were included in this study. Subjective stroke and bleeding risk estimation did not correlate with risk scores (ρ=0.08 and ρ=0.17). The majority of patients (57%) underestimated the individual stroke risk. Patients feared stroke more than bleeding (67% vs 10%). There was no relationship between accurate perception of stroke and bleeding risks and education level. However, we found a correlation between the patients' judgement of their own knowledge of AF and correct assessment of individual stroke risk (ρ=0.24, p=0.02). During follow-up, patients experienced the following events: death (n=5), stroke (n=2), bleeding (n=1). OAC discontinuation rate despite indication was 3%. In this cross-sectional analysis of OAC-naive patients with AF, we found major differences between patients' perceptions and physicians' assessments of risks and benefits of OAC. To ensure shared decision-making and informed

Estimating risks of importation and local transmission of Zika virus infection

Directory of Open Access Journals (Sweden)

Kyeongah Nah

2016-04-01

Full Text Available Background. An international spread of Zika virus (ZIKV infection has attracted global attention. ZIKV is conveyed by a mosquito vector, Aedes species, which also acts as the vector species of dengue and chikungunya viruses. Methods. Arrival time of ZIKV importation (i.e., the time at which the first imported case was diagnosed in each imported country was collected from publicly available data sources. Employing a survival analysis model in which the hazard is an inverse function of the effective distance as informed by the airline transportation network data, and using dengue and chikungunya virus transmission data, risks of importation and local transmission were estimated. Results. A total of 78 countries with imported case(s have been identified, with the arrival time ranging from 1 to 44 weeks since the first ZIKV was identified in Brazil, 2015. Whereas the risk of importation was well explained by the airline transportation network data, the risk of local transmission appeared to be best captured by additionally accounting for the presence of dengue and chikungunya viruses. Discussion. The risk of importation may be high given continued global travel of mildly infected travelers but, considering that the public health concerns over ZIKV infection stems from microcephaly, it is more important to focus on the risk of local and widespread transmission that could involve pregnant women. The predicted risk of local transmission was frequently seen in tropical and subtropical countries with dengue or chikungunya epidemic experience.

Effect Of Ventilation On Chronic Health Risks In Schools And Offices

Energy Technology Data Exchange (ETDEWEB)

Parthasarathy, Srinandini [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McKone, Thomas E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-01-04

This study provides a risk assessment for chronic health risks from inhalation exposure to indoor air pollutants in offices and schools with a focus how ventilation impacts exposures to, and risks from, volatile organic compounds (VOCs) and particulate matter (PM2.5). We estimate how much health risks could change with varying ventilation rates under two scenarios: (i) halving the measured ventilation rates and (ii) doubling the measured ventilation rates. For the hazard characterization we draw upon prior papers that identified pollutants potentially affecting health with indoor air concentrations responsive to changes in ventilation rates. For exposure assessment we determine representative concentrations of pollutants using data available in current literature and model changes in exposures with changes in ventilation rates. As a metric of disease burden, we use disability adjusted life years (DALYs) to address both cancer and non-cancer effects. We also compare exposures to guidelines published by regulatory agencies to assess chronic health risks. Chronic health risks are driven primarily by particulate matter exposure, with an estimated baseline disease burden of 150 DALYs per 100,000 people in offices and 140 DALYs per 100,000 people in schools. Study results show that PM2.5-related DALYs are not very sensitive to changes in ventilation rates. Filtration is more effective at controlling PM2.5 concentrations and health effects. Non-cancer health effects contribute only a small fraction of the overall chronic health burden of populations in offices and schools (<1 DALY per 100,000 people). Cancer health effects dominate the disease burden in schools (3 DALYs per 100,000) and offices (5 DALYs per 100,000), with formaldehyde being the primary risk driver. In spite of large uncertainties in toxicological data and dose-response modeling, our results support the finding that ventilation rate changes do not have significant impacts on estimated chronic disease

Assessment of cardiovascular risk.

LENUS (Irish Health Repository)

Cooney, Marie Therese

2010-10-01

Atherosclerotic cardiovascular disease (CVD) is the most common cause of death worldwide. Usually atherosclerosis is caused by the combined effects of multiple risk factors. For this reason, most guidelines on the prevention of CVD stress the assessment of total CVD risk. The most intensive risk factor modification can then be directed towards the individuals who will derive the greatest benefit. To assist the clinician in calculating the effects of these multiple interacting risk factors, a number of risk estimation systems have been developed. This review address several issues regarding total CVD risk assessment: Why should total CVD risk be assessed? What risk estimation systems are available? How well do these systems estimate risk? What are the advantages and disadvantages of the current systems? What are the current limitations of risk estimation systems and how can they be resolved? What new developments have occurred in CVD risk estimation?

Insulin sensitivity and mortality risk estimation in patients with type 2 ...

African Journals Online (AJOL)

Background: There is at present the dearth of information on the possible contribution of insulin resistance to scores obtained from mortality risk estimation in patients with type 2 diabetes mellitus (T2DM). Aim: This study determined the mortality risk scores in patients with T2DM and its relationship with insulin resistance.

Estimating Risk and Return Combinations for New Derivatives Funds

Directory of Open Access Journals (Sweden)

Alexandre Bona

2004-12-01

Full Text Available Active funds are typically managed by placing bets against a well defined passive bench-mark. In this context, when examining the launching of a new actively managed fund with a target expected excess rate of return relative to the benchmark equal to µ, asset managers face the problem of estimating the risk σ of excess rates of return. This estimate is critical to examine whether the product is commercially feasible and to define risk limits for the manager, if the product is launched. This paper proceeds to examine the solution to this problem assuming an especial form of the binomial model, in the context of the market timing structure advanced by Merton (1981. The paper shows that two variables are relevant for the solution of the proposed problem. The first, and the most relevant, is the skill level of the manager. A ore skilled manager is able to operate a less risky product with the same target excess rate of return µ. The second relevant variable is the trade-off between risk and return determined by existing investment opportunities in the market. The smaller the increases in risk exposure required to obtain an increase in excess returns, the less risky the product will be After solving the problem under specific assumptions, the paper proceeds to test empirically their validity using a representative sample of hedge funds in the Brazilian market. The empirical results strongly support the validity of the required assumptions.

Risks of circulatory diseases among Mayak PA workers with radiation doses estimated using the improved Mayak Worker Dosimetry System 2008

Energy Technology Data Exchange (ETDEWEB)

Moseeva, Maria B.; Azizova, Tamara V.; Grigoryeva, Evgenia S. [Southern Urals Biophysics Institute (SUBI), Ozyorsk, Chelyabinsk Region (Russian Federation); Haylock, Richard [Public Health of England, London (United Kingdom)

2014-05-15

The new Mayak Worker Dosimetry System 2008 (MWDS-2008) was published in 2013 and supersedes the Doses-2005 dosimetry system for Mayak Production Association (PA) workers. It provides revised external and internal dose estimates based on the updated occupational history data. Using MWDS-2008, a cohort of 18,856 workers first employed at one of the main Mayak PA plants during 1948-1972 and followed up to 2005 was identified. Incidence and mortality risks from ischemic heart disease (IHD) (International Classification of Diseases (ICD)-9 codes 410-414) and from cerebrovascular diseases (CVD) (ICD-9 codes 430-438) were examined in this cohort and compared with previously published risk estimates in the same cohort based on the Doses-2005 dosimetry system. Significant associations were observed between doses from external gamma-rays and IHD and CVD incidence and also between internal doses from alpha-radiation and IHD mortality and CVD incidence. The estimates of excess relative risk (ERR)/Gy were consistent with those estimates from the previous studies based on Doses-2005 system apart from the relationship between CVD incidence and internal liver dose where the ERR/Gy based on MWDS-2008 was just over three times higher than the corresponding estimate based on Doses-2005 system. Adjustment for smoking status did not show any effect on the estimates of risk from internal alpha-particle exposure. (orig.)

Genetic impact of low-level ionizing radiation: risk estimates for first and subsequent generations

International Nuclear Information System (INIS)

Abrahamson, S.

1985-01-01

This presentation is summarized as follows: (1) a discussion of the induced mutation rates/rad employed to derive central estimates for five major classes of genetic disease; (2) the expected first generation yield of mutations per million liveborn when both parents have received a gonadal exposure of 1 rad; (3) the expected yield of mutant offspring through all time from a single rad of parental exposure; (4) the impact in terms of effective years of life lost; and (5) a prediction of how many induced genetic disorders of each class should be found among the offspring of the A-bomb survivors using the risk estimates presented. 15 references, 6 tables

Estimate of person-years at risk among A-bomb survivors, Hiroshima and Nagasaki

Energy Technology Data Exchange (ETDEWEB)

Hrubec, Z

1964-11-19

Using information from the Supplementary Schedules of the 1950 National Census and from the JNIH-ABCC Life Span Study, cumulative person-years at risk in 1950 to 1960 were estimated by age ATB, sex, distance from hypocenter, radiation dose and symptoms for A-bomb survivors resident in Hiroshima and Nagasaki cities. The number of person-years at risk in 1951 to 1958 was estimated by applying the survivorship in each age group of the Adult Health Study sample during the period 1951 to 1958 to the number of survivors in 1950. To determine the number of person-years at risk from 1959 to 1960, the average yearly loss was evaluated for each exposure group for the period 1955 to 1958 in Hiroshima and for 1953 to 1958 in Nagasaki which was then applied to 1959 and 1960, respectively. The estimate of person-years among the nonexposed groups for this period was obtained from the above estimates, the total population of both cities, and the number of persons born after the A-bombing. Estimates by other associated factors were obtained by the same procedure. 20 references, 25 tables.

Estimation of Potential Population Level Effects of Contaminants on Wildlife; FINAL

International Nuclear Information System (INIS)

Loar, J.M.

2001-01-01

The objective of this project is to provide DOE with improved methods to assess risks from contaminants to wildlife populations. The current approach for wildlife risk assessment consists of comparison of contaminant exposure estimates for individual animals to literature-derived toxicity test endpoints. These test endpoints are assumed to estimate thresholds for population-level effects. Moreover, species sensitivities to contaminants is one of several criteria to be considered when selecting assessment endpoints (EPA 1997 and 1998), yet data on the sensitivities of many birds and mammals are lacking. The uncertainties associated with this approach are considerable. First, because toxicity data are not available for most potential wildlife endpoint species, extrapolation of toxicity data from test species to the species of interest is required. There is no consensus on the most appropriate extrapolation method. Second, toxicity data are represented as statistical measures (e.g., NOAEL s or LOAELs) that provide no information on the nature or magnitude of effects. The level of effect is an artifact of the replication and dosing regime employed, and does not indicate how effects might increase with increasing exposure. Consequently, slight exceedance of a LOAEL is not distinguished from greatly exceeding it. Third, the relationship of toxic effects on individuals to effects on populations is poorly estimated by existing methods. It is assumed that if the exposure of individuals exceeds levels associated with impaired reproduction, then population level effects are likely. Uncertainty associated with this assumption is large because depending on the reproductive strategy of a given species, comparable levels of reproductive impairment may result in dramatically different population-level responses. This project included several tasks to address these problems: (1) investigation of the validity of the current allometric scaling approach for interspecies extrapolation

Estimating the risk of dengue transmission from Dutch blood donors travelling to Suriname and the Dutch Caribbean.

Science.gov (United States)

Oei, W; Lieshout-Krikke, R W; Kretzschmar, M E; Zaaijer, H L; Coutinho, R A; Eersel, M; Jubithana, B; Halabi, Y; Gerstenbluth, I; Maduro, E; Tromp, M; Janssen, M P

2016-05-01

The risk of dengue transmitted by travellers is known. Methods to estimate the transmission by transfusion (TT) risk from blood donors travelling to risk areas are available, for instance, the European Up-Front Risk Assessment Tool (EUFRAT). This study aimed to validate the estimated risk from travelling donors obtained from EUFRAT. Surveillance data on notified dengue cases in Suriname and the Dutch Caribbean islands (Aruba, Curaçao, St. Maarten, Bonaire, St. Eustatius and Saba) in 2001-2011 was used to calculate local incidence rates. Information on travel and donation behaviour of Dutch donors was collected. With the EUFRAT model, the TT risks from Dutch travelling donors were calculated. Model estimates were compared with the number of infections in Dutch travellers found by laboratory tests in the Netherlands. The expected cumulative number of donors becoming infected during travels to Suriname and the Dutch Caribbean from 2001 to 2011 was estimated at 5 (95% CI, 2-11) and 86 (45-179), respectively. The infection risk inferred from the laboratory-based study was 19 (9-61) and 28 (14-92). Given the independence of the data sources, these estimates are remarkably close. The model estimated that 0·02 (0·001-0·06) and 0·40 (0·01-1·4) recipients would have been infected by these travelling donors. The EUFRAT model provided an estimate close to actual observed number of dengue infections. The dengue TT risk among Dutch travelling donors can be estimated using basic transmission, travel and donation information. The TT risk from Dutch donors travelling to Suriname and the Dutch Caribbean is small. © 2016 International Society of Blood Transfusion.

Current estimates of radiation risks and implications for dose limits

International Nuclear Information System (INIS)

Clarke, R.H.

1989-01-01

The publication of the 1988 report of UNSCEAR represents a major step forward in that there is an international consensus on the estimation of risk from exposure to ionising radiation. The estimates of fatal cancers in the UNSCEAR report are up to 4 times the values in the 1977 review. This paper will describe the reasons for the increase, the remaining uncertainties and the implications for dose limits in occupational and public exposure. (author)

Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

Science.gov (United States)

Priharti, W.; Samat, S. B.; Yasir, M. S.

2015-09-01

The radionuclides of 226Ra, 232Th and 40K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10-3 (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

Commissioning the neutron production of a Linac: Development of a simple tool for second cancer risk estimation

International Nuclear Information System (INIS)

Romero-Expósito, M.; Sánchez-Nieto, B.; Terrón, J. A.; Lopes, M. C.; Ferreira, B. C.; Grishchuk, D.; Sandín, C.; Moral-Sánchez, S.; Melchor, M.; Domingo, C.

2015-01-01

Purpose: Knowing the contribution of neutron to collateral effects in treatments is both a complex and a mandatory task. This work aims to present an operative procedure for neutron estimates in any facility using a neutron digital detector. Methods: The authors’ previous work established a linear relationship between the total second cancer risk due to neutrons (TR n ) and the number of MU of the treatment. Given that the digital detector also presents linearity with MU, its response can be used to determine the TR n per unit MU, denoted as m, normally associated to a generic Linac model and radiotherapy facility. Thus, from the number of MU of each patient treatment, the associated risk can be estimated. The feasibility of the procedure was tested by applying it in eight facilities; patients were evaluated as well. Results: From the reading of the detector under selected irradiation conditions, m values were obtained for different machines, ranging from 0.25 × 10 −4 % per MU for an Elekta Axesse at 10 MV to 6.5 × 10 −4 % per MU for a Varian Clinac at 18 MV. Using these values, TR n of patients was estimated in each facility and compared to that from the individual evaluation. Differences were within the range of uncertainty of the authors’ methodology of equivalent dose and risk estimations. Conclusions: The procedure presented here allows an easy estimation of the second cancer risk due to neutrons for any patient, given the number of MU of the treatment. It will enable the consideration of this information when selecting the optimal treatment for a patient by its implementation in the treatment planning system

Report on some methods of determining the state of convergence of Monte Carlo risk estimates

International Nuclear Information System (INIS)

Orford, J.L.; Hufton, D.; Johnson, K.

1991-05-01

The Department of the Environment is developing a methodology for assessing potential sites for the disposal of low and intermediate level radioactive wastes. Computer models are used to simulate the groundwater transport of radioactive materials from a disposal facility back to man. Monte Carlo methods are being employed to conduct a probabilistic risk assessment (pra) of potential sites. The models calculate time histories of annual radiation dose to the critical group population. The annual radiation dose to the critical group in turn specifies the annual individual risk. The distribution of dose is generally highly skewed and many simulation runs are required to predict the level of confidence in the risk estimate i.e. to determine whether the risk estimate is converged. This report describes some statistical methods for determining the state of convergence of the risk estimate. The methods described include the Shapiro-Wilk test, calculation of skewness and kurtosis and normal probability plots. A method for forecasting the number of samples needed before the risk estimate is converged is presented. Three case studies were conducted to examine the performance of some of these techniques. (author)

Methods for estimating risks to nuclear power plants from shipping

International Nuclear Information System (INIS)

Walker, D.H.; Hartman, M.G.; Robbins, T.R.

1975-01-01

Nuclear power plants sited on land near shipping lanes or offshore can be exposed to potential risks if there is nearby ship or barge traffic which involves the transport of hazardous cargo. Methods that have been developed for estimating the degree of risk are summarized. Of concern are any accidents which could lead to a release or spill of the hazardous cargo, or to an explosion. A probability of occurrence of the order of 10 -7 per year is a general guideline which has been used to judge whether or not the risk from hazards created by accidents is acceptable. This guideline has been followed in the risk assessment discussed in this paper. 19 references

Scoring Systems for Estimating the Risk of Anticoagulant-Associated Bleeding.

Science.gov (United States)

Parks, Anna L; Fang, Margaret C

2017-07-01

Anticoagulant medications are frequently used to prevent and treat thromboembolic disease. However, the benefits of anticoagulants must be balanced with a careful assessment of the risk of bleeding complications that can ensue from their use. Several bleeding risk scores are available, including the Outpatient Bleeding Risk Index, HAS-BLED, ATRIA, and HEMORR 2 HAGES risk assessment tools, and can be used to help estimate patients' risk for bleeding on anticoagulants. These tools vary by their individual risk components and in how they define and weigh clinical factors. However, it is not yet clear how best to integrate bleeding risk tools into clinical practice. Current bleeding risk scores generally have modest predictive ability and limited ability to predict the most devastating complication of anticoagulation, intracranial hemorrhage. In clinical practice, bleeding risk tools should be paired with a formal determination of thrombosis risk, as their results may be most influential for patients at the lower end of thrombosis risk, as well as for highlighting potentially modifiable risk factors for bleeding. Use of bleeding risk scores may assist clinicians and patients in making informed and individualized anticoagulation decisions. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Joint Estimation of Cardiac Toxicity and Recurrence Risks After Comprehensive Nodal Photon Versus Proton Therapy for Breast Cancer

Energy Technology Data Exchange (ETDEWEB)

Stick, Line B., E-mail: line.bjerregaard.stick@regionh.dk [Department of Clinical Oncology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen (Denmark); Yu, Jen [Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, Maryland (United States); Maraldo, Maja V. [Department of Clinical Oncology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Aznar, Marianne C. [Department of Clinical Oncology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Nuffield Department of Population Health, University of Oxford, Oxford (United Kingdom); Pedersen, Anders N. [Department of Clinical Oncology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Bentzen, Søren M. [Department of Clinical Oncology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark); Maryland Proton Treatment Center, University of Maryland School of Medicine, Baltimore, Maryland (United States); Greenebaum Comprehensive Cancer Center and Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland (United States); Vogelius, Ivan R. [Department of Clinical Oncology, Rigshospitalet, University of Copenhagen, Copenhagen (Denmark)

2017-03-15

Purpose: The study aims to perform joint estimation of the risk of recurrence caused by inadequate radiation dose coverage of lymph node targets and the risk of cardiac toxicity caused by radiation exposure to the heart. Delivered photon plans are compared with realistic proton plans, thereby providing evidence-based estimates of the heterogeneity of treatment effects in consecutive cases for the 2 radiation treatment modalities. Methods and Materials: Forty-one patients referred for postlumpectomy comprehensive nodal photon irradiation for left-sided breast cancer were included. Comparative proton plans were optimized by a spot scanning technique with single-field optimization from 2 en face beams. Cardiotoxicity risk was estimated with the model of Darby et al, and risk of recurrence following a compromise of lymph node coverage was estimated by a linear dose-response model fitted to the recurrence data from the recently published EORTC (European Organisation for Research and Treatment of Cancer) 22922/10925 and NCIC-CTG (National Cancer Institute of Canada Clinical Trials Group) MA.20 randomized controlled trials. Results: Excess absolute risk of cardiac morbidity was small with photon therapy at an attained age of 80 years, with median values of 1.0% (range, 0.2%-2.9%) and 0.5% (range, 0.03%-1.0%) with and without cardiac risk factors, respectively, but even lower with proton therapy (0.13% [range, 0.02%-0.5%] and 0.06% [range, 0.004%-0.3%], respectively). The median estimated excess absolute risk of breast cancer recurrence after 10 years was 0.10% (range, 0.0%-0.9%) with photons and 0.02% (range, 0.0%-0.07%) with protons. The association between age of the patient and benefit from proton therapy was weak, almost non-existing (Spearman rank correlations of −0.15 and −0.30 with and without cardiac risk factors, respectively). Conclusions: Modern photon therapy yields limited risk of cardiac toxicity in most patients, but proton therapy can reduce the

Propensity score estimation to address calendar time-specific channeling in comparative effectiveness research of second generation antipsychotics.

Directory of Open Access Journals (Sweden)

Stacie B Dusetzina

Full Text Available Channeling occurs when a medication and its potential comparators are selectively prescribed based on differences in underlying patient characteristics. Drug safety advisories can provide new information regarding the relative safety or effectiveness of a drug product which might increase selective prescribing. In particular, when reported adverse effects vary among drugs within a therapeutic class, clinicians may channel patients toward or away from a drug based on the patient's underlying risk for an adverse outcome. If channeling is not identified and appropriately managed it might lead to confounding in observational comparative effectiveness studies.To demonstrate channeling among new users of second generation antipsychotics following a Food and Drug Administration safety advisory and to evaluate the impact of channeling on cardiovascular risk estimates over time.Florida Medicaid data from 2001-2006.Retrospective cohort of adults initiating second generation antipsychotics. We used propensity scores to match olanzapine initiators with other second generation antipsychotic initiators. To evaluate channeling away from olanzapine following an FDA safety advisory, we estimated calendar time-specific propensity scores. We compare the performance of these calendar time-specific propensity scores with conventionally-estimated propensity scores on estimates of cardiovascular risk.Increased channeling away from olanzapine was evident for some, but not all, cardiovascular risk factors and corresponded with the timing of the FDA advisory. Covariate balance was optimized within period and across all periods when using the calendar time-specific propensity score. Hazard ratio estimates for cardiovascular outcomes did not differ across models (Conventional PS: 0.97, 95%CI: 0.81-3.18 versus calendar time-specific PS: 0.93, 95%CI: 0.77-3.04.Changes in channeling over time was evident for several covariates but had limited impact on cardiovascular risk

A non-stationary cost-benefit analysis approach for extreme flood estimation to explore the nexus of 'Risk, Cost and Non-stationarity'

Science.gov (United States)

Qi, Wei

2017-11-01

Cost-benefit analysis is commonly used for engineering planning and design problems in practice. However, previous cost-benefit based design flood estimation is based on stationary assumption. This study develops a non-stationary cost-benefit based design flood estimation approach. This approach integrates a non-stationary probability distribution function into cost-benefit analysis, and influence of non-stationarity on expected total cost (including flood damage and construction costs) and design flood estimation can be quantified. To facilitate design flood selections, a 'Risk-Cost' analysis approach is developed, which reveals the nexus of extreme flood risk, expected total cost and design life periods. Two basins, with 54-year and 104-year flood data respectively, are utilized to illustrate the application. It is found that the developed approach can effectively reveal changes of expected total cost and extreme floods in different design life periods. In addition, trade-offs are found between extreme flood risk and expected total cost, which reflect increases in cost to mitigate risk. Comparing with stationary approaches which generate only one expected total cost curve and therefore only one design flood estimation, the proposed new approach generate design flood estimation intervals and the 'Risk-Cost' approach selects a design flood value from the intervals based on the trade-offs between extreme flood risk and expected total cost. This study provides a new approach towards a better understanding of the influence of non-stationarity on expected total cost and design floods, and could be beneficial to cost-benefit based non-stationary design flood estimation across the world.

Estimation of the risks of stochastic effects attributable to the radiological conditions in Tbilisi

International Nuclear Information System (INIS)

Vepkhvadze, N.R.; Gelashvili, K.D.; Kiladze, N.A.

1997-01-01

Radiation background in Tbilisi City has been studied; collective and annual average statistic dozes have been ascertained, parameters of stochastic effects' (cancerogenic, genetic) risks caused by low dozes of ionizing radiation have been calculated. From 21 cases of total risk 7 are stipulated by genetic defects, 14 - by lethal malignant tumor. The conclusion is that we should not expect important changes in health condition of population caused by existing in Tbilisi City radiation background. (author)

Model-Based Estimation of Collision Risks of Predatory Birds with Wind Turbines

Directory of Open Access Journals (Sweden)

Marcus Eichhorn

2012-06-01

Full Text Available The expansion of renewable energies, such as wind power, is a promising way of mitigating climate change. Because of the risk of collision with rotor blades, wind turbines have negative effects on local bird populations, particularly on raptors such as the Red Kite (Milvus milvus. Appropriate assessment tools for these effects have been lacking. To close this gap, we have developed an agent-based, spatially explicit model that simulates the foraging behavior of the Red Kite around its aerie in a landscape consisting of different land-use types. We determined the collision risk of the Red Kite with the turbine as a function of the distance between the wind turbine and the aerie and other parameters. The impact function comprises the synergistic effects of species-specific foraging behavior and landscape structure. The collision risk declines exponentially with increasing distance. The strength of this decline depends on the raptor's foraging behavior, its ability to avoid wind turbines, and the mean wind speed in the region. The collision risks, which are estimated by the simulation model, are in the range of values observed in the field. The derived impact function shows that the collision risk can be described as an aggregated function of distance between the wind turbine and the raptor's aerie. This allows an easy and rapid assessment of the ecological impacts of (existing or planned wind turbines in relation to their spatial location. Furthermore, it implies that minimum buffer zones for different landscapes can be determined in a defensible way. This modeling approach can be extended to other bird species with central-place foraging behavior. It provides a helpful tool for landscape planning aimed at minimizing the impacts of wind power on biodiversity.

MCNPX dosimetry and radiation-induced cancer risk estimation from {sup 18}F-FDG pediatric PET at Brazilian population

Energy Technology Data Exchange (ETDEWEB)

Mendes, Bruno M.; Fonseca, Telma C.F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Campos, Tarcisio P.R., E-mail: bmm@cdtn.br, E-mail: tcff@cdtn.br, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (PCTN/UFMG), Belo Horizonte, MG (Brazil). Programa de Pós-Graduação em Ciências e Técnicas Nucleares

2017-07-01

Positron emission tomography (PET) using {sup 18}F-FDG has increased significantly in pediatric patients. PET with {sup 18}F-FDG has often been applied in oncology. Cancer induction is one of the main stochastic risk from exposure to ionizing radiation of {sup 18}F-FDG. Radiation-induced cancer risk estimation due to medical exposures is an important tool for risk/benefit assessing. The objective was to perform dosimetry and estimate the risk of cancer induction due to pediatric use of {sup 18}F-FDG. MCNPX Computational dosimetry was performed to estimate organ absorbed doses resulting from {sup 18}F-FDG pediatric use. Two voxelized phantoms, kindly provided by the GSF - Helmholtz Zentrum, were used: 'Child' - 7 years child and 'Baby' 8-week-old infant. ICRP-128 publication provided the radiopharmaceutical biodistribution of F-18. Tables containing organ absorbed dose and effective dose per unit of injected activity for the two phantoms were obtained. The injected activities were estimated according to data provided in the literature. Images of the absorbed dose distribution were generated from both models. The BEIR VII methodology was used to calculate the risk of cancer induction. The risk of cancer induction (per imaging procedure) for the seven-year-old child was (0.09% ♂ and 0.15% ♀) and for the eight-week old baby was (0.11% ♂ and 0.21% ♀). The {sup 18}F-FDG absorbed dose distribution in the children and infants showed some divergences in comparison to adult data. Probably, the biokinetic data used to children and infants is the main reason for this disconnection. (author)

Estimation of insurance premiums for coverage against natural disaster risk: an application of Bayesian Inference

NARCIS (Netherlands)

Paudel, Y.; Botzen, W.J.W.; Aerts, J.C.J.H.

2013-01-01

This study applies Bayesian Inference to estimate flood risk for 53 dyke ring areas in the Netherlands, and focuses particularly on the data scarcity and extreme behaviour of catastrophe risk. The probability density curves of flood damage are estimated through Monte Carlo simulations. Based on

The public and effective risk communication

NARCIS (Netherlands)

Frewer, L.J.

2004-01-01

Abstract Public perceptions of risk have often been dismissed on the basis of ¿irrationality¿, and have tended to be excluded from policy processes by risk assessors and managers. People¿s responses to different risks are determined by psychological factors. The technical risk estimates

Estimation of insurance premiums for coverage against natural disaster risk: an application of Bayesian Inference

Directory of Open Access Journals (Sweden)

Y. Paudel

2013-03-01

Full Text Available This study applies Bayesian Inference to estimate flood risk for 53 dyke ring areas in the Netherlands, and focuses particularly on the data scarcity and extreme behaviour of catastrophe risk. The probability density curves of flood damage are estimated through Monte Carlo simulations. Based on these results, flood insurance premiums are estimated using two different practical methods that each account in different ways for an insurer's risk aversion and the dispersion rate of loss data. This study is of practical relevance because insurers have been considering the introduction of flood insurance in the Netherlands, which is currently not generally available.

Estimation of insurance premiums for coverage against natural disaster risk: an application of Bayesian Inference

Science.gov (United States)

Paudel, Y.; Botzen, W. J. W.; Aerts, J. C. J. H.

2013-03-01

This study applies Bayesian Inference to estimate flood risk for 53 dyke ring areas in the Netherlands, and focuses particularly on the data scarcity and extreme behaviour of catastrophe risk. The probability density curves of flood damage are estimated through Monte Carlo simulations. Based on these results, flood insurance premiums are estimated using two different practical methods that each account in different ways for an insurer's risk aversion and the dispersion rate of loss data. This study is of practical relevance because insurers have been considering the introduction of flood insurance in the Netherlands, which is currently not generally available.

An estimate of the radiation-induced cancer risk from the whole-body stray radiation exposure in neutron radiotherapy

International Nuclear Information System (INIS)

Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

1982-01-01

1980 BEIR III risk factors have been used to estimate the secondary cancer risks from the whole-body stray radiation exposures occurring in neutron radiotherapy. Risks were calculated using linear, linear-quadratic and quadratic dose-response models for the gamma component of the stray radiation. The linear dose-response model was used to calculate risk for the neutron component of the stray radiation. These estimates take into consideration for the first time the age and sex distribution of patients undergoing neutron therapy. Changes in risk as a function of the RBE (10-100) assigned to the stray neutron radiation component have also been assessed. Excess risks in neutron-treated patients have been compared with excess risks for photon-treated patients and with the expected incidence of cancer in a normal population having the same age and sex distribution. Results indicate that it will be necessary to tolerate a higher incidence of secondary cancers in patients undergoing fast neutron therapy than is the case with conventional photon therapy. For neutron RBEs of less than 50 the increased risk is only a fraction of the normal expected incidence of cancer in this population. Comparison of the radiation-induced risk with reported normal tissue complication rates in the treatment volume indicates that the excess cancer risk is substantially lower than the risk from other late normal tissue effects. (author)

Estimating radiation-induced cancer risk using MVK two-stage model for carcinogenesis

International Nuclear Information System (INIS)

Kai, M.; Kusama, T.; Aoki, Y.

1993-01-01

Based on the carcinogenesis model as proposed by Moolgavkar et al., time-dependent relative risk models were derived for projecting the time variation in excess relative risk. If it is assumed that each process is described by time-independent linear dose-response relationship, the time variation in excess relative risk is influenced by the parameter related with the promotion process. The risk model based carcinogenesis theory would play a marked role in estimating radiation-induced cancer risk in constructing a projection model or transfer model

Developing an objective evaluation method to estimate diabetes risk in community-based settings.

Science.gov (United States)

Kenya, Sonjia; He, Qing; Fullilove, Robert; Kotler, Donald P

2011-05-01

Exercise interventions often aim to affect abdominal obesity and glucose tolerance, two significant risk factors for type 2 diabetes. Because of limited financial and clinical resources in community and university-based environments, intervention effects are often measured with interviews or questionnaires and correlated with weight loss or body fat indicated by body bioimpedence analysis (BIA). However, self-reported assessments are subject to high levels of bias and low levels of reliability. Because obesity and body fat are correlated with diabetes at different levels in various ethnic groups, data reflecting changes in weight or fat do not necessarily indicate changes in diabetes risk. To determine how exercise interventions affect diabetes risk in community and university-based settings, improved evaluation methods are warranted. We compared a noninvasive, objective measurement technique--regional BIA--with whole-body BIA for its ability to assess abdominal obesity and predict glucose tolerance in 39 women. To determine regional BIA's utility in predicting glucose, we tested the association between the regional BIA method and blood glucose levels. Regional BIA estimates of abdominal fat area were significantly correlated (r = 0.554, P < 0.003) with fasting glucose. When waist circumference and family history of diabetes were added to abdominal fat in multiple regression models, the association with glucose increased further (r = 0.701, P < 0.001). Regional BIA estimates of abdominal fat may predict fasting glucose better than whole-body BIA as well as provide an objective assessment of changes in diabetes risk achieved through physical activity interventions in community settings.

UV radiation: sources, effects and risks of human and environmental exposure

International Nuclear Information System (INIS)

Eggink, G.J.; Slaper, H.

1992-01-01

This paper summarizes the principal results of a review study on UV- -exposure and UV related risks in the Netherlands. Both the present state of affairs and future developments are discussed, the latter partly based on model calculations. The sun is the main UV source to which the whole population is exposed. Solar exposure is estimated to amount at least 90% of the annual UV burden for the Dutch population. For certain groups in the population man made sources are estimated to contribute considerably to the yearly UV dose. Ozone depletion as a result of human activities, growing use of tungsten halogen lamps and increasing application of UV-sources in industry and medicine all tend to increase UV exposure. UV exposure can lead to a wide variety of health effects, among which the induction of skin cancer, skin aging, cataract formation and suppression of immune responses. Risk estimates of these health effects are available for skin cancer and to a lesser extend for cataracts. The estimated UV related skin cancer incidence rate in the Netherlands is 10 -3 per year (15 000 cases), and the associated mortality rate amounts to 6-25·10 -6 per year (90-400 deaths). The ozone depletion presently observed over the past decade (5% in the Netherlands), is expected to lead to an increased annual mortality rate due to skin cancer of 1,3·10 -6 per year. Environmental exposure can influence plant physiology and lead to a decrease of biomass in aquatic as well as terrestrial ecosystems. This may result in adverse effects on the foodweb and biodiversity of ecosystems. Quantitative risk estimates for these effects are very uncertain or lacking. (author)

New NRC methodology for estimating biological risks from exposure to ionizing radiation

International Nuclear Information System (INIS)

Willis, C.A; Branagan, E.F.

1983-01-01

In licensing commercial nuclear power reactors, in the US Nuclear Regulatory Commission considers the potential health effects from the release of radioactive effluents. This entails reliance on epidemiological study results and interpretations. The BEIR III report is a principal source of information but as newer information becomes available, it is desirable to include this in NRC models. To facilitate both the estimation of potential health effects and the evaluation of epidemiological study results, the NRC has supported the development of a new computer code (SPAHR). This new code utilizes much more comprehensive demographic models than did the previously used codes (CAIRD and BIERMOD). SPAHR can accommodate variations in all the principal demographic statistics such as age distribution, age-specific computing risks, and sex ratio. Also SPAHR can project effects over a number of generations

Using Structured Additive Regression Models to Estimate Risk Factors of Malaria: Analysis of 2010 Malawi Malaria Indicator Survey Data

Science.gov (United States)

Chirombo, James; Lowe, Rachel; Kazembe, Lawrence

2014-01-01

Background After years of implementing Roll Back Malaria (RBM) interventions, the changing landscape of malaria in terms of risk factors and spatial pattern has not been fully investigated. This paper uses the 2010 malaria indicator survey data to investigate if known malaria risk factors remain relevant after many years of interventions. Methods We adopted a structured additive logistic regression model that allowed for spatial correlation, to more realistically estimate malaria risk factors. Our model included child and household level covariates, as well as climatic and environmental factors. Continuous variables were modelled by assuming second order random walk priors, while spatial correlation was specified as a Markov random field prior, with fixed effects assigned diffuse priors. Inference was fully Bayesian resulting in an under five malaria risk map for Malawi. Results Malaria risk increased with increasing age of the child. With respect to socio-economic factors, the greater the household wealth, the lower the malaria prevalence. A general decline in malaria risk was observed as altitude increased. Minimum temperatures and average total rainfall in the three months preceding the survey did not show a strong association with disease risk. Conclusions The structured additive regression model offered a flexible extension to standard regression models by enabling simultaneous modelling of possible nonlinear effects of continuous covariates, spatial correlation and heterogeneity, while estimating usual fixed effects of categorical and continuous observed variables. Our results confirmed that malaria epidemiology is a complex interaction of biotic and abiotic factors, both at the individual, household and community level and that risk factors are still relevant many years after extensive implementation of RBM activities. PMID:24991915

Medical effects and risks of exposure to ionising radiation

International Nuclear Information System (INIS)

Mettler, Fred A

2012-01-01

Effects and risk from exposure to ionising radiation depend upon the absorbed dose, dose rate, quality of radiation, specifics of the tissue irradiated and other factors such as the age of the individual. Effects may be apparent almost immediately or may take decades to be manifest. Cancer is the most important stochastic effect at absorbed doses of less than 1 Gy. The risk of cancer induction varies widely across different tissues; however, the risk of fatal radiation-induced cancer for a general population following chronic exposure is about 5% Sv −1 . Quantification of cancer risk at doses of less than 0.1 Gy remains problematic. Hereditary risks from irradiation that might result in effects to offspring of humans appear to be much lower and any such potential risks can only be estimated from animal models. At high doses (over 1 Gy) cell killing and modification causes deterministic effects such as skin burns, and bone marrow depression, in which case immunosuppression becomes a critical issue. Acute whole body penetrating gamma irradiation at doses in excess of 2 Gy results in varying degrees of acute radiation sickness and doses over 10 Gy are usually lethal as a result of combined organ injury. (note)

Quantitative Risk reduction estimation Tool For Control Systems, Suggested Approach and Research Needs

Energy Technology Data Exchange (ETDEWEB)

Miles McQueen; Wayne Boyer; Mark Flynn; Sam Alessi

2006-03-01

For the past year we have applied a variety of risk assessment technologies to evaluate the risk to critical infrastructure from cyber attacks on control systems. More recently, we identified the need for a stand alone control system risk reduction estimation tool to provide owners and operators of control systems with a more useable, reliable, and credible method for managing the risks from cyber attack. Risk is defined as the probability of a successful attack times the value of the resulting loss, typically measured in lives and dollars. Qualitative and ad hoc techniques for measuring risk do not provide sufficient support for cost benefit analyses associated with cyber security mitigation actions. To address the need for better quantitative risk reduction models we surveyed previous quantitative risk assessment research; evaluated currently available tools; developed new quantitative techniques [17] [18]; implemented a prototype analysis tool to demonstrate how such a tool might be used; used the prototype to test a variety of underlying risk calculational engines (e.g. attack tree, attack graph); and identified technical and research needs. We concluded that significant gaps still exist and difficult research problems remain for quantitatively assessing the risk to control system components and networks, but that a useable quantitative risk reduction estimation tool is not beyond reach.

Measurement of natural radionuclides in Malaysian bottled mineral water and consequent health risk estimation

Energy Technology Data Exchange (ETDEWEB)

Priharti, W.; Samat, S. B.; Yasir, M. S. [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

2015-09-25

The radionuclides of {sup 226}Ra, {sup 232}Th and {sup 40}K were measured in ten mineral water samples, of which from the radioactivity obtained, the ingestion doses for infants, children and adults were calculated and the cancer risk for the adult was estimated. Results showed that the calculated ingestion doses for the three age categories are much lower than the average worldwide ingestion exposure of 0.29 mSv/y and the estimated cancer risk is much lower than the cancer risk of 8.40 × 10{sup −3} (estimated from the total natural radiation dose of 2.40 mSv/y). The present study concludes that the bottled mineral water produced in Malaysia is safe for daily human consumption.

Estimating the Risks of Breast Cancer Radiotherapy

DEFF Research Database (Denmark)

Taylor, Carolyn; Correa, Candace; Duane, Frances K

2017-01-01

Purpose Radiotherapy reduces the absolute risk of breast cancer mortality by a few percentage points in suitable women but can cause a second cancer or heart disease decades later. We estimated the absolute long-term risks of modern breast cancer radiotherapy. Methods First, a systematic literature...... review was performed of lung and heart doses in breast cancer regimens published during 2010 to 2015. Second, individual patient data meta-analyses of 40,781 women randomly assigned to breast cancer radiotherapy versus no radiotherapy in 75 trials yielded rate ratios (RRs) for second primary cancers...... and cause-specific mortality and excess RRs (ERRs) per Gy for incident lung cancer and cardiac mortality. Smoking status was unavailable. Third, the lung or heart ERRs per Gy in the trials and the 2010 to 2015 doses were combined and applied to current smoker and nonsmoker lung cancer and cardiac mortality...

A risk adjustment approach to estimating the burden of skin disease in the United States.

Science.gov (United States)

Lim, Henry W; Collins, Scott A B; Resneck, Jack S; Bolognia, Jean; Hodge, Julie A; Rohrer, Thomas A; Van Beek, Marta J; Margolis, David J; Sober, Arthur J; Weinstock, Martin A; Nerenz, David R; Begolka, Wendy Smith; Moyano, Jose V

2018-01-01

Direct insurance claims tabulation and risk adjustment statistical methods can be used to estimate health care costs associated with various diseases. In this third manuscript derived from the new national Burden of Skin Disease Report from the American Academy of Dermatology, a risk adjustment method that was based on modeling the average annual costs of individuals with or without specific diseases, and specifically tailored for 24 skin disease categories, was used to estimate the economic burden of skin disease. The results were compared with the claims tabulation method used in the first 2 parts of this project. The risk adjustment method estimated the direct health care costs of skin diseases to be $46 billion in 2013, approximately $15 billion less than estimates using claims tabulation. For individual skin diseases, the risk adjustment cost estimates ranged from 11% to 297% of those obtained using claims tabulation for the 10 most costly skin disease categories. Although either method may be used for purposes of estimating the costs of skin disease, the choice of method will affect the end result. These findings serve as an important reference for future discussions about the method chosen in health care payment models to estimate both the cost of skin disease and the potential cost impact of care changes. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Estimation of on-farm interventions to control Campylobacter

DEFF Research Database (Denmark)

Sommer, Helle Mølgaard; Borck Høg, Birgitte; Rosenquist, Hanne

2015-01-01

Before making risk management decisions to control Campylobacter prevalence in broiler flocks, it is useful to identify effective interventions. A given risk factor may seem to have a large effect, but in practice interventions related to this risk factor may have only limited effect due...... to a relative small proportion of the farms that can actually be intervened for the given risk factors. We present a novel tool for risk assessors to obtain such estimates of the effect of interventions before it is implemented at the farms. A statistical method was developed in order to estimate the flock...... population. In the present study risk factor estimates from a European study was used and the reference population consisted of data from the risk factor study plus extra data from a large questionnaire survey to improve the representativeness of the reference population. The results showed that some...

Patients with Testicular Cancer Undergoing CT Surveillance Demonstrate a Pitfall of Radiation-induced Cancer Risk Estimates: The Timing Paradox

Science.gov (United States)

Eisenberg, Jonathan D.; Lee, Richard J.; Gilmore, Michael E.; Turan, Ekin A.; Singh, Sarabjeet; Kalra, Mannudeep K.; Liu, Bob; Kong, Chung Yin; Gazelle, G. Scott

2013-01-01

Purpose: To demonstrate a limitation of lifetime radiation-induced cancer risk metrics in the setting of testicular cancer surveillance—in particular, their failure to capture the delayed timing of radiation-induced cancers over the course of a patient’s lifetime. Materials and Methods: Institutional review board approval was obtained for the use of computed tomographic (CT) dosimetry data in this study. Informed consent was waived. This study was HIPAA compliant. A Markov model was developed to project outcomes in patients with testicular cancer who were undergoing CT surveillance in the decade after orchiectomy. To quantify effects of early versus delayed risks, life expectancy losses and lifetime mortality risks due to testicular cancer were compared with life expectancy losses and lifetime mortality risks due to radiation-induced cancers from CT. Projections of life expectancy loss, unlike lifetime risk estimates, account for the timing of risks over the course of a lifetime, which enabled evaluation of the described limitation of lifetime risk estimates. Markov chain Monte Carlo methods were used to estimate the uncertainty of the results. Results: As an example of evidence yielded, 33-year-old men with stage I seminoma who were undergoing CT surveillance were projected to incur a slightly higher lifetime mortality risk from testicular cancer (598 per 100 000; 95% uncertainty interval [UI]: 302, 894) than from radiation-induced cancers (505 per 100 000; 95% UI: 280, 730). However, life expectancy loss attributable to testicular cancer (83 days; 95% UI: 42, 124) was more than three times greater than life expectancy loss attributable to radiation-induced cancers (24 days; 95% UI: 13, 35). Trends were consistent across modeled scenarios. Conclusion: Lifetime radiation risk estimates, when used for decision making, may overemphasize radiation-induced cancer risks relative to short-term health risks. © RSNA, 2012 Supplemental material: http

Recent advances in the estimation of genetic risks of exposure to ionizing radiation

International Nuclear Information System (INIS)

Sankaranarayanan, K.

2002-01-01

This paper reviews the major advances that have occurred during the last few years in the estimation of genetic risks of exposure of human populations to ionizing radiation. Among these are: (i) an upward revision of the estimates of the baseline frequencies of Mendelian diseases (from 1.25% to 2.4%); (ii) the conceptual change to the use of a doubling dose based on human data on spontaneous mutation rates and mouse data on induced mutation rates (from the one based entirely on mouse data on spontaneous and induced mutation rates, which was the case thus far); (iii) the fuller development of the concept of mutation component (MC) and its application to predict the responsiveness of Mendelian and chronic multi factorial diseases to induced mutations; (iv) the introduction of the concept that the major adverse effects of radiation exposure of human germ cells are likely to be manifest as multi-system developmental abnormalities and (v) the introduction of concept of potential recoverability correction factor (PRCF) to bridge the gap between induced mutations studied in mice and the risk of genetic disease in humans are reviewed

Bevacizumab in Treatment of High-Risk Ovarian Cancer—A Cost-Effectiveness Analysis

Science.gov (United States)

Herzog, Thomas J.; Hu, Lilian; Monk, Bradley J.; Kiet, Tuyen; Blansit, Kevin; Kapp, Daniel S.; Yu, Xinhua

2014-01-01

Objective. The objective of this study was to evaluate a cost-effectiveness strategy of bevacizumab in a subset of high-risk advanced ovarian cancer patients with survival benefit. Methods. A subset analysis of the International Collaboration on Ovarian Neoplasms 7 trial showed that additions of bevacizumab (B) and maintenance bevacizumab (mB) to paclitaxel (P) and carboplatin (C) improved the overall survival (OS) of high-risk advanced cancer patients. Actual and estimated costs of treatment were determined from Medicare payment. Incremental cost-effectiveness ratio per life-year saved was established. Results. The estimated cost of PC is $535 per cycle; PCB + mB (7.5 mg/kg) is $3,760 per cycle for the first 6 cycles and then $3,225 per cycle for 12 mB cycles. Of 465 high-risk stage IIIC (>1 cm residual) or stage IV patients, the previously reported OS after PC was 28.8 months versus 36.6 months in those who underwent PCB + mB. With an estimated 8-month improvement in OS, the incremental cost-effectiveness ratio of B was $167,771 per life-year saved. Conclusion. In this clinically relevant subset of women with high-risk advanced ovarian cancer with overall survival benefit after bevacizumab, our economic model suggests that the incremental cost of bevacizumab was approximately $170,000. PMID:24721817

Accounting for individualized competing mortality risks in estimating postmenopausal breast cancer risk

Science.gov (United States)

Schonberg, Mara A.; Li, Vicky W.; Eliassen, A. Heather; Davis, Roger B.; LaCroix, Andrea Z.; McCarthy, Ellen P.; Rosner, Bernard A.; Chlebowski, Rowan T.; Hankinson, Susan E.; Marcantonio, Edward R.; Ngo, Long H.

2016-01-01

Purpose Accurate risk assessment is necessary for decision-making around breast cancer prevention. We aimed to develop a breast cancer prediction model for postmenopausal women that would take into account their individualized competing risk of non-breast cancer death. Methods We included 73,066 women who completed the 2004 Nurses’ Health Study (NHS) questionnaire (all ≥57 years) and followed participants until May 2014. We considered 17 breast cancer risk factors (health behaviors, demographics, family history, reproductive factors), 7 risk factors for non-breast cancer death (comorbidities, functional dependency), and mammography use. We used competing risk regression to identify factors independently associated with breast cancer. We validated the final model by examining calibration (expected-to-observed ratio of breast cancer incidence, E/O) and discrimination (c-statistic) using 74,887 subjects from the Women’s Health Initiative Extension Study (WHI-ES; all were ≥55 years and followed for 5 years). Results Within 5 years, 1.8% of NHS participants were diagnosed with breast cancer (vs. 2.0% in WHI-ES, p=0.02) and 6.6% experienced non-breast cancer death (vs. 5.2% in WHI-ES, prisk factors, 5 comorbidities, functional dependency, and mammography use. The model’s c-statistic was 0.61 (95% CI [0.60–0.63]) in NHS and 0.57 (0.55–0.58) in WHI-ES. On average our model under predicted breast cancer in WHI-ES (E/O 0.92 [0.88–0.97]). Conclusions We developed a novel prediction model that factors in postmenopausal women’s individualized competing risks of non-breast cancer death when estimating breast cancer risk. PMID:27770283

[Ionizing and non-ionizing radiation (comparative risk estimations)].

Science.gov (United States)

Grigor'ev, Iu G

2012-01-01

The population has widely used mobile communication for already more than 15 years. It is important to note that the use of mobile communication has sharply changed the conditions of daily exposure of the population to EME We expose our brain daily for the first time in the entire civilization. The mobile phone is an open and uncontrollable source of electromagnetic radiation. The comparative risk estimation for the population of ionizing and non-ionizing radiation was carried out taking into account the real conditions of influence. Comparison of risks for the population of ionizing and non-ionizing radiation leads us to a conclusion that EMF RF exposure in conditions of wide use of mobile communication is potentially more harmful than ionizing radiation influence.

Commissioning the neutron production of a Linac: Development of a simple tool for second cancer risk estimation

Energy Technology Data Exchange (ETDEWEB)

Romero-Expósito, M., E-mail: mariateresa.romero@uab.cat [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Sánchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41009 (Spain); Lopes, M. C. [Serviço de Física Médica, Instituto Português de Oncologia, Coimbra 3000-075 (Portugal); Ferreira, B. C. [i3N, Department of Physics, University of Aveiro, Aveiro 3810-193 (Portugal); Grishchuk, D. [Radiotherapy Service, Russian Research Center for Radiology and Surgical Technology, Saint Petersburg 197758 (Russian Federation); Sandín, C. [Elekta, Ltd., Crawley RH10 9RR (United Kingdom); Moral-Sánchez, S. [Servicio de Radiofísica, Instituto Onkologikoa, San Sebastián 20014 (Spain); Melchor, M. [Servicio de Radiofísica, Hospital Universitario de la Ribera, Alzira 46600, Valencia (Spain); Domingo, C. [Departament de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); and others

2015-01-15

Purpose: Knowing the contribution of neutron to collateral effects in treatments is both a complex and a mandatory task. This work aims to present an operative procedure for neutron estimates in any facility using a neutron digital detector. Methods: The authors’ previous work established a linear relationship between the total second cancer risk due to neutrons (TR{sup n}) and the number of MU of the treatment. Given that the digital detector also presents linearity with MU, its response can be used to determine the TR{sup n} per unit MU, denoted as m, normally associated to a generic Linac model and radiotherapy facility. Thus, from the number of MU of each patient treatment, the associated risk can be estimated. The feasibility of the procedure was tested by applying it in eight facilities; patients were evaluated as well. Results: From the reading of the detector under selected irradiation conditions, m values were obtained for different machines, ranging from 0.25 × 10{sup −4}% per MU for an Elekta Axesse at 10 MV to 6.5 × 10{sup −4}% per MU for a Varian Clinac at 18 MV. Using these values, TR{sup n} of patients was estimated in each facility and compared to that from the individual evaluation. Differences were within the range of uncertainty of the authors’ methodology of equivalent dose and risk estimations. Conclusions: The procedure presented here allows an easy estimation of the second cancer risk due to neutrons for any patient, given the number of MU of the treatment. It will enable the consideration of this information when selecting the optimal treatment for a patient by its implementation in the treatment planning system.

Aid decision algorithms to estimate the risk in congenital heart surgery.

Science.gov (United States)

Ruiz-Fernández, Daniel; Monsalve Torra, Ana; Soriano-Payá, Antonio; Marín-Alonso, Oscar; Triana Palencia, Eddy

2016-04-01

In this paper, we have tested the suitability of using different artificial intelligence-based algorithms for decision support when classifying the risk of congenital heart surgery. In this sense, classification of those surgical risks provides enormous benefits as the a priori estimation of surgical outcomes depending on either the type of disease or the type of repair, and other elements that influence the final result. This preventive estimation may help to avoid future complications, or even death. We have evaluated four machine learning algorithms to achieve our objective: multilayer perceptron, self-organizing map, radial basis function networks and decision trees. The architectures implemented have the aim of classifying among three types of surgical risk: low complexity, medium complexity and high complexity. Accuracy outcomes achieved range between 80% and 99%, being the multilayer perceptron method the one that offered a higher hit ratio. According to the results, it is feasible to develop a clinical decision support system using the evaluated algorithms. Such system would help cardiology specialists, paediatricians and surgeons to forecast the level of risk related to a congenital heart disease surgery. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The impact of advances in human molecular biology on radiation genetic risk estimation in man

International Nuclear Information System (INIS)

Sankaranarayanan, K.

1996-01-01

This paper provides an overview of the conceptual framework, the data base, methods and assumptions used thus far to assess the genetic risks of exposure of human populations to ionising radiation. These are then re-examined in the contemporary context of the rapidly expanding knowledge of the molecular biology of human mendelian diseases. This re-examination reveals that (i) many of the assumptions used thus far in radiation genetic risk estimation may not be fully valid and (ii) the current genetic risk estimates are probably conservative, but provide an adequate margin of safety for radiological protection. The view is expressed that further advances in the field of genetic risk estimation will be largely driven by advances in the molecular biology of human genetic diseases. (author). 37 refs., 5 tabs

Development and prospective validation of a model estimating risk of readmission in cancer patients.

Science.gov (United States)

Schmidt, Carl R; Hefner, Jennifer; McAlearney, Ann S; Graham, Lisa; Johnson, Kristen; Moffatt-Bruce, Susan; Huerta, Timothy; Pawlik, Timothy M; White, Susan

2018-02-26

Hospital readmissions among cancer patients are common. While several models estimating readmission risk exist, models specific for cancer patients are lacking. A logistic regression model estimating risk of unplanned 30-day readmission was developed using inpatient admission data from a 2-year period (n = 18 782) at a tertiary cancer hospital. Readmission risk estimates derived from the model were then calculated prospectively over a 10-month period (n = 8616 admissions) and compared with actual incidence of readmission. There were 2478 (13.2%) unplanned readmissions. Model factors associated with readmission included: emergency department visit within 30 days, >1 admission within 60 days, non-surgical admission, solid malignancy, gastrointestinal cancer, emergency admission, length of stay >5 days, abnormal sodium, hemoglobin, or white blood cell count. The c-statistic for the model was 0.70. During the 10-month prospective evaluation, estimates of readmission from the model were associated with higher actual readmission incidence from 20.7% for the highest risk category to 9.6% for the lowest. An unplanned readmission risk model developed specifically for cancer patients performs well when validated prospectively. The specificity of the model for cancer patients, EMR incorporation, and prospective validation justify use of the model in future studies designed to reduce and prevent readmissions. © 2018 Wiley Periodicals, Inc.

Performance of models for estimating absolute risk difference in multicenter trials with binary outcome

Directory of Open Access Journals (Sweden)

Claudia Pedroza

2016-08-01

Full Text Available Abstract Background Reporting of absolute risk difference (RD is recommended for clinical and epidemiological prospective studies. In analyses of multicenter studies, adjustment for center is necessary when randomization is stratified by center or when there is large variation in patients outcomes across centers. While regression methods are used to estimate RD adjusted for baseline predictors and clustering, no formal evaluation of their performance has been previously conducted. Methods We performed a simulation study to evaluate 6 regression methods fitted under a generalized estimating equation framework: binomial identity, Poisson identity, Normal identity, log binomial, log Poisson, and logistic regression model. We compared the model estimates to unadjusted estimates. We varied the true response function (identity or log, number of subjects per center, true risk difference, control outcome rate, effect of baseline predictor, and intracenter correlation. We compared the models in terms of convergence, absolute bias and coverage of 95 % confidence intervals for RD. Results The 6 models performed very similar to each other for the majority of scenarios. However, the log binomial model did not converge for a large portion of the scenarios including a baseline predictor. In scenarios with outcome rate close to the parameter boundary, the binomial and Poisson identity models had the best performance, but differences from other models were negligible. The unadjusted method introduced little bias to the RD estimates, but its coverage was larger than the nominal value in some scenarios with an identity response. Under the log response, coverage from the unadjusted method was well below the nominal value (<80 % for some scenarios. Conclusions We recommend the use of a binomial or Poisson GEE model with identity link to estimate RD for correlated binary outcome data. If these models fail to run, then either a logistic regression, log Poisson

Estimation of lung cancer risk from environmental exposure to airborne plutonium from the Rocky Flats Plant

International Nuclear Information System (INIS)

Sutherland, J.V.

1983-01-01

A three-phase study was undertaken to (1) determine the nature of disagreement among scientists concerning risk of environmental release of plutonium, (2) develop an analytic procedure for determining risk based on clearly stated principles defensible by reference to the literature, and (3) develop estimates of radiation dose to the lung from exposure to plutonium in ambient air for the purpose of evaluating risk to an individual with a specified age and smoking history. Eleven epidemiologists, biostatisticians and radiation scientists participated in Phase I of the study. It was shown that no clearly stated analytical principles for risk estimation were in common use, resulting in widely divergent risk estimates. Five of these disagreeing scientists in Phase I (including all cancer epidemiologists in the Denver metropolitan area) were chosen for Phase II of the study. A single analytic procedure was developed which was unanimously agreed upon. This procedure was dependent on the estimate of dose to the lung from ambient air levels of Rocky Flats plutonium. In Phase III of the study, a panel of four radiation scientists developed a procedure for estimation of dose to the lung from chronic exposure to plutonium ambient air levels. Results from all phases of the study were used to develop a method for estimation of relative risk of lung cancer for an individual, given plutonium dose to the lung, age, smoking history and other radiation exposure

Radiobiology in clinical radiation therapy - Part IV: Long term risks - Carcinogenic, hereditary, and teratogenetic effects

International Nuclear Information System (INIS)

Brenner, David J.

1996-01-01

The long-term risks induced by radiation are of much concern to patients and clinicians alike. As an example, perceived radiation risks are frequently cited in a woman's decision to choose a radical mastectomy over lumpectomy + radiation. In consequence, the actual radiation risks are often considerably overstated, or unreasonably downplayed. In this lecture we will discuss just what is known about the long term risks following radiotherapy, both from the human experience and from the laboratory. We will discuss risks both to the patient and to radiotherapy personnel. A good deal is known about the carcinogenic effects of high and low doses of radiation, in large part thanks to the careful study of the survivors of the atomic bombing in Japan, as well as studies of individuals exposed to medical x rays. It is possible to make an estimate, which is probably good to within a factor of, perhaps, three to five, of the cancer risks faced by a patient of a particular age and sex who is going to undergo a particular radiotherapeutic regimen. It is also possible to make an estimate of the risks faced by radiotherapy and nursing staff exposed to low doses. Brachytherapy related risk estimates are likely to be somewhat more uncertain, due to the poorly known sparing effects of the low dose rates used; for the radiotherapy personnel in brachytherapy, because of the doses which can be received, the risks can be quite significant. A recent complication in external-beam radiotherapy is the advent of high-energy linacs, which can produce a significant fast neutron dose which, dose for dose, may be ten to fifty times more carcinogenic than gamma rays. Data relating to the risks of hereditary effects of radiation come almost entirely from laboratory experiments in animals. Studies involving several million mice form the basis of most of our current understanding of hereditary effects. The results of these studies indicate that radiation is a relatively inefficient mutagen. The

Interactions of Lipid Genetic Risk Scores with Estimates of Metabolic Health in a Danish Population

DEFF Research Database (Denmark)

Justesen, Johanne M; Allin, Kristine H; Sandholt, Camilla H

2015-01-01

Background—There are several well-established lifestyle factors influencing dyslipidemia and currently; 157 genetic susceptibility loci have been reported to be associated with serum lipid levels at genome-wide statistical significance. However, the interplay between lifestyle risk factors...... and these susceptibility loci has not been fully elucidated. We tested whether genetic risk scores (GRS) of lipid-associated single nucleotide polymorphisms associate with fasting serum lipid traits and whether the effects are modulated by lifestyle factors or estimates of metabolic health. Methods and Results—The single......-cholesterol, high-density lipoprotein-cholesterol, or triglyceride, 4 weighted GRS were constructed. In a cross-sectional design, we investigated whether the effect of these weighted GRSs on lipid levels were modulated by diet, alcohol consumption, physical activity, and smoking or the individual metabolic health...

Estimating population health risk from low-level environmental radon

International Nuclear Information System (INIS)

Fisher, D.R.

1980-01-01

Although incidence of respiratory cancer is directly related to inhalation of radon and radon daughters, the magnitude of the actual risk is uncertain for members of the general population exposed for long periods to low-level concentrations. Currently, any such estimate of the risk must rely on data obtained through previous studies of underground-miner populations. Several methods of risk analysis have resulted from these studies. Since the breathing atmospheres, smoking patterns, and physiology are different between miners and the general public, overestimates of lung cancer risk to the latter may have resulted. Strong evidence exists to support the theory of synergistic action between alpha radiation and other agents, and therefore a modified relative risk model was developed to predict lung cancer risks to the general public. The model considers latent period, observation period, age dependency, and inherent risks from smoking or geographical location. A test of the model showed excellent agreement with results of the study of Czechoslovakian uranium miners, for which the necessary time factors were available. The risk model was also used to predict lung cancer incidence among residents of homes on reclaimed Florida phosphate lands, and results of this analysis indicate that over the space of many years, the increased incidence of lung cancer due to elevated radon levels may be indisgtinguishable from those due to other causes

Radiobiological risk estimates of adverse events and secondary cancer for proton and photon radiation therapy of pediatric medulloblastoma

DEFF Research Database (Denmark)

Brodin, N Patrik; Munck af Rosenschöld, Per Martin; Aznar, Marianne C

2011-01-01

The aim of this model study was to estimate and compare the risk of radiation-induced adverse late effects in pediatric patients with medulloblastoma (MB) treated with either three-dimensional conformal radiotherapy (3D CRT), inversely-optimized arc therapy (RapidArc(®) (RA)) or spot...

Possibility of use of plant test systems for estimation of degree risk at radiation influence

International Nuclear Information System (INIS)

Gogebashvili, M.E; Ivanishvili, N.I.

2011-01-01

Full tex:Now one of the major problems of radiobiology is studying of degree risks at influence of small doses of an ionizing radiation. It is known, that not tumoral forms of the remote pathology are not stochastic, threshold, reactions of an organism to beam influence, frequency and weight depend on a dose, while carcinogenic and genetic effects (stochastic reactions) - frequency raises with dose increase. Last years the general hypothesis for definition of the raised risk in the irradiated populations, based on the theoretical analysis of extensive researches of various biological objects and epidemiological data, assumes existence of difficult parities between a dose of an irradiation and frequency of investigated effect. In this aspect the special importance is got by biological models with which help reception of quantitative parameters of influence of modifying factors for creation of more exact systems of monitoring of the remote radiobiological effects is possible.One of such systems is reciprocal grows reaction of stamen threads of plant tradescantia. At the heart of action of the given biomodel that growth tradescantia threads occurs from one initial cell is, and level of its radiating damage is shown in number of the subsequent cellular generation during the postradiating period. For an estimation of adequacy of the given model we had been chose two kinds tradescantia - Tradescantia virginiana L. and Tradescantia rosea Vent.In work two basic criteria of an estimation of radiating damage - quantity of viable pollen threads and quantity of viable cells in each of threads have been used. The received results have shown strict correlation of reciprocal postradiating effects between used variants.It is known, that at studying of influence of damaging factors of environment, including radiating, on live organisms the concept r iskcharacterizes degree of danger of influence expressed in quantity indicators. Thus, in most general case this includes probability

Estimating oil price 'Value at Risk' using the historical simulation approach

International Nuclear Information System (INIS)

David Cabedo, J.; Moya, Ismael

2003-01-01

In this paper we propose using Value at Risk (VaR) for oil price risk quantification. VaR provides an estimation for the maximum oil price change associated with a likelihood level, and can be used for designing risk management strategies. We analyse three VaR calculation methods: the historical simulation standard approach, the historical simulation with ARMA forecasts (HSAF) approach, developed in this paper, and the variance-covariance method based on autoregressive conditional heteroskedasticity models forecasts. The results obtained indicate that HSAF methodology provides a flexible VaR quantification, which fits the continuous oil price movements well and provides an efficient risk quantification

Estimating oil price 'Value at Risk' using the historical simulation approach

International Nuclear Information System (INIS)

Cabedo, J.D.; Moya, I.

2003-01-01

In this paper we propose using Value at Risk (VaR) for oil price risk quantification. VaR provides an estimation for the maximum oil price change associated with a likelihood level, and can be used for designing risk management strategies. We analyse three VaR calculation methods: the historical simulation standard approach, the historical simulation with ARMA forecasts (HSAF) approach. developed in this paper, and the variance-covariance method based on autoregressive conditional heteroskedasticity models forecasts. The results obtained indicate that HSAF methodology provides a flexible VaR quantification, which fits the continuous oil price movements well and provides an efficient risk quantification. (author)

Estimates of Present and Future Flood Risk in the Conterminous United States

Science.gov (United States)

Wing, O.; Bates, P. D.; Smith, A.; Sampson, C. C.; Johnson, K.; Fargione, J.; Morefield, P.

2017-12-01

Past attempts to estimate flood risk across the USA either have incomplete coverage, coarse resolution or use overly simplified models of the flooding process. In this paper, we use a new 30m resolution model of the entire conterminous US (CONUS) with realistic flood physics to produce estimates of flood hazard which match to within 90% accuracy the skill of local models built with detailed data. Socio-economic data of commensurate resolution are combined with these flood depths to estimate current and future flood risk. Future population and land-use projections from the US Environmental Protection Agency (USEPA) are employed to indicate how flood risk might change through the 21st Century, while present-day estimates utilize the Federal Emergency Management Agency (FEMA) National Structure Inventory and a USEPA map of population distribution. Our data show that the total CONUS population currently exposed to serious flooding is 2.6 to 3.1 times higher than previous estimates; with nearly 41 million Americans living within the so-called 1 in 100-year (1% annual probability) floodplain, compared to only 13 million according to FEMA flood maps. Moreover, socio-economic change alone leads to significant future increases in flood exposure and risk, even before climate change impacts are accounted for. The share of the population living on the 1 in 100-year floodplain is projected to increase from 13.3% in the present-day to 15.6 - 15.8% in 2050 and 16.4 - 16.8% in 2100. The area of developed land within this floodplain, currently at 150,000 km2, is likely to increase by 37 - 72% in 2100 based on the scenarios selected. 5.5 trillion worth of assets currently lie on the 1% floodplain; we project that by 2100 this number will exceed 10 trillion. With this detailed spatial information on present-day flood risk, federal and state agencies can take appropriate action to mitigate losses. Use of USEPA population and land-use projections mean that particular attention can be

National and subnational mortality effects of metabolic risk factors and smoking in Iran: a comparative risk assessment

Directory of Open Access Journals (Sweden)

Farzadfar Farshad

2011-10-01

Full Text Available Abstract Background Mortality from cardiovascular and other chronic diseases has increased in Iran. Our aim was to estimate the effects of smoking and high systolic blood pressure (SBP, fasting plasma glucose (FPG, total cholesterol (TC, and high body mass index (BMI on mortality and life expectancy, nationally and subnationally, using representative data and comparable methods. Methods We used data from the Non-Communicable Disease Surveillance Survey to estimate means and standard deviations for the metabolic risk factors, nationally and by region. Lung cancer mortality was used to measure cumulative exposure to smoking. We used data from the death registration system to estimate age-, sex-, and disease-specific numbers of deaths in 2005, adjusted for incompleteness using demographic methods. We used systematic reviews and meta-analyses of epidemiologic studies to obtain the effect of risk factors on disease-specific mortality. We estimated deaths and life expectancy loss attributable to risk factors using the comparative risk assessment framework. Results In 2005, high SBP was responsible for 41,000 (95% uncertainty interval: 38,000, 44,000 deaths in men and 39,000 (36,000, 42,000 deaths in women in Iran. High FPG, BMI, and TC were responsible for about one-third to one-half of deaths attributable to SBP in men and/or women. Smoking was responsible for 9,000 deaths among men and 2,000 among women. If SBP were reduced to optimal levels, life expectancy at birth would increase by 3.2 years (2.6, 3.9 and 4.1 years (3.2, 4.9 in men and women, respectively; the life expectancy gains ranged from 1.1 to 1.8 years for TC, BMI, and FPG. SBP was also responsible for the largest number of deaths in every region, with age-standardized attributable mortality ranging from 257 to 333 deaths per 100,000 adults in different regions. Discussion Management of blood pressure through diet, lifestyle, and pharmacological interventions should be a priority in Iran

Uncertainty estimation and risk prediction in air quality

International Nuclear Information System (INIS)

Garaud, Damien

2011-01-01

This work is about uncertainty estimation and risk prediction in air quality. Firstly, we build a multi-model ensemble of air quality simulations which can take into account all uncertainty sources related to air quality modeling. Ensembles of photochemical simulations at continental and regional scales are automatically generated. Then, these ensemble are calibrated with a combinatorial optimization method. It selects a sub-ensemble which is representative of uncertainty or shows good resolution and reliability for probabilistic forecasting. This work shows that it is possible to estimate and forecast uncertainty fields related to ozone and nitrogen dioxide concentrations or to improve the reliability of threshold exceedance predictions. The approach is compared with Monte Carlo simulations, calibrated or not. The Monte Carlo approach appears to be less representative of the uncertainties than the multi-model approach. Finally, we quantify the observational error, the representativeness error and the modeling errors. The work is applied to the impact of thermal power plants, in order to quantify the uncertainty on the impact estimates. (author) [fr

A framework for estimating radiation-related cancer risks in Japan from the 2011 Fukushima nuclear accident.

Science.gov (United States)

Walsh, L; Zhang, W; Shore, R E; Auvinen, A; Laurier, D; Wakeford, R; Jacob, P; Gent, N; Anspaugh, L R; Schüz, J; Kesminiene, A; van Deventer, E; Tritscher, A; del Rosarion Pérez, M

2014-11-01

We present here a methodology for health risk assessment adopted by the World Health Organization that provides a framework for estimating risks from the Fukushima nuclear accident after the March 11, 2011 Japanese major earthquake and tsunami. Substantial attention has been given to the possible health risks associated with human exposure to radiation from damaged reactors at the Fukushima Daiichi nuclear power station. Cumulative doses were estimated and applied for each post-accident year of life, based on a reference level of exposure during the first year after the earthquake. A lifetime cumulative dose of twice the first year dose was estimated for the primary radionuclide contaminants ((134)Cs and (137)Cs) and are based on Chernobyl data, relative abundances of cesium isotopes, and cleanup efforts. Risks for particularly radiosensitive cancer sites (leukemia, thyroid and breast cancer), as well as the combined risk for all solid cancers were considered. The male and female cumulative risks of cancer incidence attributed to radiation doses from the accident, for those exposed at various ages, were estimated in terms of the lifetime attributable risk (LAR). Calculations of LAR were based on recent Japanese population statistics for cancer incidence and current radiation risk models from the Life Span Study of Japanese A-bomb survivors. Cancer risks over an initial period of 15 years after first exposure were also considered. LAR results were also given as a percentage of the lifetime baseline risk (i.e., the cancer risk in the absence of radiation exposure from the accident). The LAR results were based on either a reference first year dose (10 mGy) or a reference lifetime dose (20 mGy) so that risk assessment may be applied for relocated and non-relocated members of the public, as well as for adult male emergency workers. The results show that the major contribution to LAR from the reference lifetime dose comes from the first year dose. For a dose of 10 mGy in

Cost-effectiveness of Nutritional Counseling for Obese Patients and Patients at Risk of Ischemic Heart Disease

DEFF Research Database (Denmark)

Olsen, Jens; Willain, I.; Ladelund, S.

2005-01-01

OBJECTIVES: Obesity and dyslipidemia are risk factors for ischemic heart disease, and prevention and treatment in primary care can reduce these risks. The objective of this cost-effectiveness analysis was to compare the costs and effects (in terms of life years gained) of providing nutritional...... counseling by a general practitioner (GP) or a dietician. METHODS: A total of 60 GPs, who accepted to participate, were randomized either to give nutritional counseling or to refer patients to a dietician for counseling. The life years gained was estimated using a Cox regression model. Costs were estimated...... proven that the GP group was the most cost-effective-the cost of gaining 1 extra life year was estimated to be 8213 DKK compared with the dietician group, for which the incremental cost-effectiveness ratio was estimated to be 59,987 DKK. CONCLUSIONS: The effects were moderate, but other studies of other...

Evaluation of organ dose and estimation of risk due to the abdominal region radiography in Indian adults

International Nuclear Information System (INIS)

Kumaresan, M.; Chaubey, Ajay; Kantharia, Surita; Karira, V.; Kumar, Rajesh; Biju, K.; Rao, B.S.

2006-01-01

Organ dose, risk of carcinogenesis and genetic effect due to the abdominal region radiography in Indian adult with the help of Monte-Carlo MCNP code by measuring the entrance skin dose by LiF: Mg, Cu, P TL phosphor and the risk coefficients provided by ICRP 60 were estimated. The entrance skin dose for abdominal region radiography was ranges from 2.75 mSv to 18.88 mSv while average entrance skin dose was 8.3 mSv. The bladder, testes and ovary are the important organ those are getting higher dose. The maximum dose for testes, ovary and bladder is 5.37 mSv, 1.45 mSv and 4.74 mSv respectively. The frequency of occurrence of fatal cancers and serious genetic disorders as a consequence of abdominal region radiography ranges from 0.1 to 38.8 risk/10 6 of fatal cancer. Although the estimated risks are small but cannot be neglected. It is important to avoid unnecessary repetitions and also to carry out proper quality assurance tests on the equipment and in the long run it will help reduce the risks and maximize the benefits of radiodiagnosis. These studies may lead to setting up of national reference levels for the diagnostic procedures India. (author)

The use of importance sampling in a trial assessment to obtain converged estimates of radiological risk

International Nuclear Information System (INIS)

Johnson, K.; Lucas, R.

1986-12-01

In developing a methodology for assessing potential sites for the disposal of radioactive wastes, the Department of the Environment has conducted a series of trial assessment exercises. In order to produce converged estimates of radiological risk using the SYVAC A/C simulation system an efficient sampling procedure is required. Previous work has demonstrated that importance sampling can substantially increase sampling efficiency. This study used importance sampling to produce converged estimates of risk for the first DoE trial assessment. Four major nuclide chains were analysed. In each case importance sampling produced converged risk estimates with between 10 and 170 times fewer runs of the SYVAC A/C model. This increase in sampling efficiency can reduce the total elapsed time required to obtain a converged estimate of risk from one nuclide chain by a factor of 20. The results of this study suggests that the use of importance sampling could reduce the elapsed time required to perform a risk assessment of a potential site by a factor of ten. (author)

A Methodology of Health Effects Estimation from Air Pollution in Large Asian Cities

Directory of Open Access Journals (Sweden)

Keiko Hirota

2017-09-01

Full Text Available The increase of health effects caused by air pollution seems to be a growing concern in Asian cities with increasing motorization. This paper discusses methods of estimating the health effects of air pollution in large Asian cities. Due to the absence of statistical data in Asia, this paper carefully chooses the methodology using data of the Japanese compensation system. A basic idea of health effects will be captured from simple indicators, such as population and air quality, in a correlation model. This correlation model enables more estimation results of respiratory mortality caused by air pollution to be yielded than by using the relative model. The correlation model could be an alternative method to estimate mortality besides the relative risk model since the results of the correlation model are comparable with those of the relative model by city and by time series. The classification of respiratory diseases is not known from the statistical yearbooks in many countries. Estimation results could support policy decision-making with respect to public health in a cost-effective way.

Biomechanical Indices for Rupture Risk Estimation in Abdominal Aortic Aneurysms

NARCIS (Netherlands)

Leemans, Eva L.; Willems, Tineke P.; van der Laan, Maarten J.; Slump, Cornelis H.; Zeebregts, Clark J.

2017-01-01

Purpose: To review the use of biomechanical indices for the estimation of abdominal aortic aneurysm (AAA) rupture risk, emphasizing their potential use in a clinical setting. Methods: A search of the PubMed, Embase, Scopus, and Compendex databases was made up to June 2015 to identify articles

Long-term modelling for estimation of man-induced environmental risks

International Nuclear Information System (INIS)

Mahura, A.; Baklanov, A.; Sorensen, J.H.; Tridvornov, A.

2006-01-01

Full text: As a part of the EU coordination action project ENVIRO-RISKS the long-term regional and transboundary atmospheric transport, dispersion, and deposition of atmospheric pollutants is investigated. Focus is on pollutants originating at nuclear and chemical risk sites of the NIS countries. Potential sources of atmospheric pollution include chemical and metallurgical enterprises and smelters, former testing polygons of nuclear weapons, and nuclear plants and facilities. These are situated within territories of Kazakhstan, Ukraine, and Russia (the Siberian, Ural, Krasnoyarsk, and Kola regions). The atmospheric pollutants considered are radionuclides such as Cs-137, I-131, and Sr-90 as well as sulphates and heavy metals. The Danish Emergency Model for Atmosphere (DERMA) is employed for simulations using 3D meteorological fields from the European Center for Medium-range Weather Forecasts. The modeled concentration and deposition fields of atmospheric pollutants are used as input into further collaborative studies to estimate the man-induced environmental risks from regionally and remotely located potential sources with a focus on Siberian territories. The temporal and spatial variability of these fields and the probabilities and contribution of removal during atmospheric transport are evaluated. Possible approaches for further GIS integration and use of obtained results are discussed with respect to estimation of man-received doses and risks, impact on environment with a focus on forests, applicability for integrated systems for regional environmental monitoring and management, and others. (author)

Estimating the mediating effect of different biomarkers on the relation of alcohol consumption with the risk of type 2 diabetes

NARCIS (Netherlands)

Beulens, J.W.J.; Schouw, van der Y.T.; Moons, K.G.M.; Boshuizen, H.C.; A, van der D.L.; Groenwold, R.H.H.

2013-01-01

Purpose Moderate alcohol consumption is associated with a reduced type 2 diabetes risk, but the biomarkers that explain this relation are unknown. The most commonly used method to estimate the proportion explained by a biomarker is the difference method. However, influence of alcohol–biomarker

Estimation of foetus risk from x-ray pelvimetric examinations

International Nuclear Information System (INIS)

Iba, Shozo; Sato, Kazuichi

1983-01-01

X-ray pelvimetric examinations are carried out for the purpose of diagnosing the cephalo pelvic disproportion at terminal pregnancy and they are still an excellent method, being performed more often than other examinations. However the invitable fetal exposure is considered to be a significant dose and makes an estimation of stochastic fetal risk related to x-ray exposure and to investigate the methods of dose reduction. As the methods judging the exposure dose actually made in the hospitals, a questionnarie regarding the main technical factors of an x-ray examination was given to 26 hospitals, including 5 university hospitals, in Kantou district, and the answeres were analyzed. The estimated risks involving genetics, leukemia and malignant diseases were dependent on the exposure dose which could be calculated on the basis of the technical factors obtained. Total risks on the foetus ranged widely from 1.27 x 10 rad -1 to 1.19 x 10 rad -1 . So for as we have investigated, if all the hospitals used a grid ratio of 5:1, a tube voltage of 120 kV, intensitying screens with rare earth phosphors and green-sensitive orthomatic medical x-ray films for the x-ray pelvimetric examinations, it would be possible to reduce the present exposure dose by one-fourth. The ratio of the x-ray pelvimetry taken on pregnant patients ranged from 2 % to 33 %, having a mean value of 15 %. (author)

Radiation-Induced Second Cancer Risk Estimates From Radionuclide Therapy

Science.gov (United States)

Bednarz, Bryan; Besemer, Abigail

2017-09-01

The use of radionuclide therapy in the clinical setting is expected to increase significantly over the next decade. There is an important need to understand the radiation-induced second cancer risk associated with these procedures. In this study the radiation-induced cancer risk in five radionuclide therapy patients was investigated. These patients underwent serial SPECT imaging scans following injection as part of a clinical trial testing the efficacy of a 131Iodine-labeled radiopharmaceutical. Using these datasets the committed absorbed doses to multiple sensitive structures were calculated using RAPID, which is a novel Monte Carlo-based 3D dosimetry platform developed for personalized dosimetry. The excess relative risk (ERR) for radiation-induced cancer in these structures was then derived from these dose estimates following the recommendations set forth in the BEIR VII report. The radiation-induced leukemia ERR was highest among all sites considered reaching a maximum value of approximately 4.5. The radiation-induced cancer risk in the kidneys, liver and spleen ranged between 0.3 and 1.3. The lifetime attributable risks (LARs) were also calculated, which ranged from 30 to 1700 cancers per 100,000 persons and were highest for leukemia and the liver for both males and females followed by radiation-induced spleen and kidney cancer. The risks associated with radionuclide therapy are similar to the risk associated with external beam radiation therapy.

Dynamic Estimation of Volatility Risk Premia and Investor Risk Aversion from Option-Implied and Realized Volatilities

DEFF Research Database (Denmark)

Bollerslev, Tim; Gibson, Michael; Zhou, Hao

experiment confirms that the procedure works well in practice. Implementing the procedure with actual S&P500 option-implied volatilities and high-frequency five-minute-based realized volatilities indicates significant temporal dependencies in the estimated stochastic volatility risk premium, which we in turn...

Effectiveness of personalized and interactive health risk calculators: a randomized trial.

Science.gov (United States)

Harle, Christopher A; Downs, Julie S; Padman, Rema

2012-01-01

Risk calculators are popular websites that provide individualized disease risk assessments to the public. Little is known about their effect on risk perceptions and health behavior. This study sought to test whether risk calculator features-namely, personalized estimates of one's disease risk and feedback about the effects of risk-mitigating behaviors-improve risk perceptions and motivate healthy behavior. A web-based experimental study using simple randomization was conducted to compare the effects of 3 prediabetes risk communication websites. Setting The study was conducted in the context of ongoing health promotion activities sponsored by a university's human resources office. Patients Participants were adult university employees. Intervention The control website presented nonindividualized risk information. The personalized noninteractive website presented individualized risk calculations. The personalized interactive website presented individualized risk calculations and feedback about the effects of hypothetical risk-mitigating behaviors. Measurements Pre- and postintervention risk perceptions were measured in absolute and relative terms. Health behavior was measured by assessing participant interest in follow-up preventive health services. On average, risk perceptions decreased by 2%. There was no general effect of personalization or interactivity in aligning subjective risk perceptions with objective risk calculations or in increasing healthy behaviors. However, participants who previously overestimated their risk reduced their perceptions by 16%. This was a significantly larger change than the 2% increase by participants who underestimated their risk. Limitations Results may not generalize to different populations, different diseases, or longer-term outcomes. Compared to nonpersonalized information, individualized risk calculators had little positive effect on prediabetes risk perception accuracy or health behavior. Risk perception accuracy was improved in

The effect of emotions on risk perception: Experimental evaluation of the affective tendencies framework

Directory of Open Access Journals (Sweden)

Drače Saša

2012-01-01

Full Text Available The aim of this study was to assess the role of specific emotions on risk perception providing a more stringent experimental test of the Appraisal Tendencies Framework (ATF. Consistent with expectations, angry and happy participants made more optimistic risk estimates than participants who were made sad. As hypothesized by ATF, happiness and anger also led people to somewhat higher certainty appraisals than sadness. However, this change in perception did not mediate the impact of emotions on risk estimates. Taken together, our results provide the evidence for causal role of specific emotions in risk perception and contribute to literature showing that the effects of emotion on judgment are not solely due to the valence of the experienced emotion. However, they also suggest that the processes underlying emotion effects remain in need for further specifications.

Estimating the Health Risk Associated with the Use of Ecological Sanitation Toilets in Malawi

Directory of Open Access Journals (Sweden)

Save Kumwenda

2017-01-01

Full Text Available Use of Ecological Sanitation (EcoSan sludge is becoming popular due to increasing price of organic fertilizers in Malawi; however, there is little evidence on the associated risks. Quantitative microbiological risk assessment (QMRA was done to determine health risks associated with use of EcoSan. Pathogens considered included Escherichia coli (E. coli, Salmonella, and soil transmitted helminths (STHs. Exponential and Beta Poisson models were used to estimate the risk from helminthic and bacterial pathogens, respectively. Main exposure pathways were through poor storage of sludge, contamination of foods during drying, walking barefoot on the ground contaminated with sludge, pit emptying without protection, and application of sludge in the fields. Estimated annual risk for Ascaris lumbricoides, Taenia, and hookworms was approximately over 5.6 × 10−1 for both Fossa Alternas (FAs and Urine Diverting Dry Toilet (UDDTs. Risk from E. coli and Salmonella was 8.9 × 10−2 and above. The risks were higher than WHO acceptable risk for use of faecal sludge in crops of 10−4 infections per year. Promoters and users of EcoSan latrines need to consider advocating for strict guidelines to reduce the risk.

Some statistical considerations related to the estimation of cancer risk following exposure to ionizing radiation

International Nuclear Information System (INIS)

Land, C.E.; Pierce, D.A.

1983-01-01

Statistical theory and methodology provide the logical structure for scientific inference about the cancer risk associated with exposure to ionizing radiation. Although much is known about radiation carcinogenesis, the risk associated with low-level exposures is difficult to assess because it is too small to measure directly. Estimation must therefore depend upon mathematical models which relate observed risks at high exposure levels to risks at lower exposure levels. Extrapolated risk estimates obtained using such models are heavily dependent upon assumptions about the shape of the dose-response relationship, the temporal distribution of risk following exposure, and variation of risk according to variables such as age at exposure, sex, and underlying population cancer rates. Expanded statistical models, which make explicit certain assumed relationships between different data sets, can be used to strengthen inferences by incorporating relevant information from diverse sources. They also allow the uncertainties inherent in information from related data sets to be expressed in estimates which partially depend upon that information. To the extent that informed opinion is based upon a valid assessment of scientific data, the larger context of decision theory, which includes statistical theory, provides a logical framework for the incorporation into public policy decisions of the informational content of expert opinion

Introduction to dosimetry and risk estimation of second cancer induction following radiotherapy

International Nuclear Information System (INIS)

Harrison, R.M.

2013-01-01

This brief review of dosimetry in second cancer dosimetry introduces work carried out by Working Group 9 (Radiation Protection Dosimetry in Medicine) of the European Radiation Dosimetry Group (EURADOS). The work described in the following papers in this edition was presented at a Workshop on Dosimetry for Second Cancer Risk Estimation given at the EURADOS Annual meeting in Vienna on February 8th 2012. The work concentrates on the measurement of out-of-field doses in water tanks and BOMAB-like phantoms using a variety of dosimeters to measure photon and neutron doses. These include optically stimulated luminescence (OSL), radiophotoluminescence (RPL) and thermoluminescence (TLD) dosimeters for photon dosimetry (together with ion chambers for reference measurements traceable to primary standards) and track etch and bubble detectors for neutron measurements. A discussion of the various phantoms available for these measurements is presented together with a brief introduction to a model for the relationship between organ doses and the risk of induction of second cancers. The estimation of second cancer risks is not trivial and involves processes which are currently incompletely understood. However, progress in this field requires a robust foundation and methodology for the measurement or calculation of organ doses following radiotherapy, so that risks can be placed in perspective, algorithms for out-of-field doses can be compared with measured data, and future epidemiological studies may have a reliable foundation of organ dosimetry for retrospective dosimetry studies. -- Highlights: ► Brief review of second cancer induction following radiotherapy. ► Out-of-field doses for estimating risks to remote organs. ► Introduction to dosimetry techniques and dosimeters used. ► Out-of-field dose measurements in phantoms

Fear, anger, and risk.

Science.gov (United States)

Lerner, J S; Keltner, D

2001-07-01

Drawing on an appraisal-tendency framework (J. S. Lerner & D. Keltner, 2000), the authors predicted and found that fear and anger have opposite effects on risk perception. Whereas fearful people expressed pessimistic risk estimates and risk-averse choices, angry people expressed optimistic risk estimates and risk-seeking choices. These opposing patterns emerged for naturally occurring and experimentally induced fear and anger. Moreover, estimates of angry people more closely resembled those of happy people than those of fearful people. Consistent with predictions, appraisal tendencies accounted for these effects: Appraisals of certainty and control moderated and (in the case of control) mediated the emotion effects. As a complement to studies that link affective valence to judgment outcomes, the present studies highlight multiple benefits of studying specific emotions.

Evaluating shielding effectiveness for reducing space radiation cancer risks

International Nuclear Information System (INIS)

Cucinotta, Francis A.; Kim, Myung-Hee Y.; Ren, Lei

2006-01-01

We discuss calculations of probability distribution functions (PDF) representing uncertainties in projecting fatal cancer risk from galactic cosmic rays (GCR) and solar particle events (SPE). The PDFs are used in significance tests for evaluating the effectiveness of potential radiation shielding approaches. Uncertainties in risk coefficients determined from epidemiology data, dose and dose-rate reduction factors, quality factors, and physics models of radiation environments are considered in models of cancer risk PDFs. Competing mortality risks and functional correlations in radiation quality factor uncertainties are included in the calculations. We show that the cancer risk uncertainty, defined as the ratio of the upper value of 95% confidence interval (CI) to the point estimate is about 4-fold for lunar and Mars mission risk projections. For short-stay lunar missions ( 180d) or Mars missions, GCR risks may exceed radiation risk limits that are based on acceptable levels of risk. For example, the upper 95% CI exceeding 10% fatal risk for males and females on a Mars mission. For reducing GCR cancer risks, shielding materials are marginally effective because of the penetrating nature of GCR and secondary radiation produced in tissue by relativistic particles. At the present time, polyethylene or carbon composite shielding cannot be shown to significantly reduce risk compared to aluminum shielding based on a significance test that accounts for radiobiology uncertainties in GCR risk projection

Estimation of transient increases in bleeding risk associated with physical activity in children with haemophilia

Directory of Open Access Journals (Sweden)

Latimer Jane

2008-06-01

Full Text Available Abstract Background Although it is widely appreciated that vigorous physical activity can increase the risk of bleeding episodes in children with haemophilia, the magnitude of the increase in risk is not known. Accurate risk estimates could inform decisions made by children with haemophilia and their parents about participation in physical activity and aid the development of optimal prophylactic schedules. The aim of this study is to provide an accurate estimate of the risks of bleeding associated with vigorous physical activity in children with haemophilia. Methods/Design The study will be a case-crossover study nested within a prospective cohort study. Children with moderate or severe haemophilia A or B, recruited from two paediatric haematology departments in Australia, will participate in the study. The child, or the child's parent or guardian, will report bleeding episodes experienced over a 12-month period. Following a bleeding episode, the participant will be interviewed by telephone about exposures to physical activity in the case period (8 hours before the bleed and 2 control periods (an 8 hour period at the same time on the day preceding the bleed and an 8 hour period two days preceding the bleed. Conditional logistic regression will be used to estimate the risk of participating in vigorous physical activity from measures of exposure to physical activity in the case and control periods. Discussion This case-control study will provide estimates of the risk of participation in vigorous physical activity in children with haemophilia.

Estimating the risk of re-emergence after stopping polio vaccination

Directory of Open Access Journals (Sweden)

Akira eSasaki

2012-05-01

Full Text Available Live vaccination against polio has effectively prevented outbreaks in most developed countries for more than 40 years, and there remain only a few countries where outbreaks of poliomyelitis by the wild strain still threaten the community. It is expected that worldwide eradication will be eventually achieved through careful surveillance and a well-managed immunization program. The present paper argues, however, that based on a simple stochastic model the risk of outbreak by a vaccine-derived strain after the cessation of vaccination is quite high, even if many years have passed since the last confirmed case. As vaccinated hosts are natural reservoirs for virulent poliovirus, the source of the risk is the vaccination itself, employed to prevent the outbreaks. The crisis after stopping vaccination will emerge when the following two conditions are met: the susceptible host density exceeds the threshold for epidemics and the vaccinated host density remains large enough to ensure the occurrence of virulent mutants in the population. Our estimates for transmission, recovery, and mutation rates, show that the probability of an outbreak of vaccine-derived virulent viruses easily exceeds 90%. Moreover, if a small fraction of hosts have a longer infectious period, as observed in individuals with innate immunodeficiency, the risk of an outbreak rises significantly. Under such conditions, successful global eradication of polio is restricted to a certain range of parameters even if inactive polio vaccine (IPV is extensively used after the termination of live vaccination.

Methodology to estimate the cost of the severe accidents risk / maximum benefit; Metodologia para estimar el costo del riesgo de accidentes severos / beneficio maximo

Energy Technology Data Exchange (ETDEWEB)

Mendoza, G.; Flores, R. M.; Vega, E., E-mail: gozalo.mendoza@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2016-09-15

For programs and activities to manage aging effects, any changes to plant operations, inspections, maintenance activities, systems and administrative control procedures during the renewal period should be characterized, designed to manage the effects of aging as required by 10 Cfr Part 54 that could impact the environment. Environmental impacts significantly different from those described in the final environmental statement for the current operating license should be described in detail. When complying with the requirements of a license renewal application, the Severe Accident Mitigation Alternatives (SAMA) analysis is contained in a supplement to the environmental report of the plant that meets the requirements of 10 Cfr Part 51. In this paper, the methodology for estimating the cost of severe accidents risk is established and discussed, which is then used to identify and select the alternatives for severe accident mitigation, which are analyzed to estimate the maximum benefit that an alternative could achieve if this eliminate all risk. Using the regulatory analysis techniques of the US Nuclear Regulatory Commission (NRC) estimates the cost of severe accidents risk. The ultimate goal of implementing the methodology is to identify candidates for SAMA that have the potential to reduce the severe accidents risk and determine if the implementation of each candidate is cost-effective. (Author)

137Cs Radiological risk estimation of NSD facility at Karawang site by using RESRAD onsite application: effect of cover thickness

Science.gov (United States)

Setiawan, B.; Prihastuti, S.; Moersidik, S. S.

2018-02-01

The operational of near surface disposal facility during waste packages loading activity into the facility, or in a monitoring activity around disposal facility at Karawang area is predicted to give a radiological risk to radiation workers. The thickness of disposal facility cover system affected the number of radiological risk of workers. Due to this reason, a radiological risk estimation needs to be considered. RESRAD onsite code is applied for this purpose by analyse the individual accepted dose and radiological risk data of radiation workers. The obtained results and then are compared with radiation protection reference in accordance with national regulation. In this case, the data from the experimental result of Karawang clay as host of disposal facility such as Kd value of 137Cs was used. Results showed that the thickness of the cover layer of disposal facility affected to the radiological risk which accepted by workers in a near surface disposal facility.