Science.gov

Sample records for adjusted risk estimates

  1. Sensitivity of health risk estimates to air quality adjustment procedure

    SciTech Connect

    Whitfield, R.G.

    1997-06-30

    This letter is a summary of risk results associated with exposure estimates using two-parameter Weibull and quadratic air quality adjustment procedures (AQAPs). New exposure estimates were developed for children and child-occurrences, six urban areas, and five alternative air quality scenarios. In all cases, the Weibull and quadratic results are compared to previous results, which are based on a proportional AQAP.

  2. What's the Risk? A Simple Approach for Estimating Adjusted Risk Measures from Nonlinear Models Including Logistic Regression

    PubMed Central

    Kleinman, Lawrence C; Norton, Edward C

    2009-01-01

    Objective To develop and validate a general method (called regression risk analysis) to estimate adjusted risk measures from logistic and other nonlinear multiple regression models. We show how to estimate standard errors for these estimates. These measures could supplant various approximations (e.g., adjusted odds ratio [AOR]) that may diverge, especially when outcomes are common. Study Design Regression risk analysis estimates were compared with internal standards as well as with Mantel–Haenszel estimates, Poisson and log-binomial regressions, and a widely used (but flawed) equation to calculate adjusted risk ratios (ARR) from AOR. Data Collection Data sets produced using Monte Carlo simulations. Principal Findings Regression risk analysis accurately estimates ARR and differences directly from multiple regression models, even when confounders are continuous, distributions are skewed, outcomes are common, and effect size is large. It is statistically sound and intuitive, and has properties favoring it over other methods in many cases. Conclusions Regression risk analysis should be the new standard for presenting findings from multiple regression analysis of dichotomous outcomes for cross-sectional, cohort, and population-based case–control studies, particularly when outcomes are common or effect size is large. PMID:18793213

  3. Risk Prediction for Prostate Cancer Recurrence Through Regularized Estimation with Simultaneous Adjustment for Nonlinear Clinical Effects*

    PubMed Central

    Long, Qi; Chung, Matthias; Moreno, Carlos S.; Johnson, Brent A.

    2011-01-01

    In biomedical studies, it is of substantial interest to develop risk prediction scores using high-dimensional data such as gene expression data for clinical endpoints that are subject to censoring. In the presence of well-established clinical risk factors, investigators often prefer a procedure that also adjusts for these clinical variables. While accelerated failure time (AFT) models are a useful tool for the analysis of censored outcome data, it assumes that covariate effects on the logarithm of time-to-event are linear, which is often unrealistic in practice. We propose to build risk prediction scores through regularized rank estimation in partly linear AFT models, where high-dimensional data such as gene expression data are modeled linearly and important clinical variables are modeled nonlinearly using penalized regression splines. We show through simulation studies that our model has better operating characteristics compared to several existing models. In particular, we show that there is a non-negligible effect on prediction as well as feature selection when nonlinear clinical effects are misspecified as linear. This work is motivated by a recent prostate cancer study, where investigators collected gene expression data along with established prognostic clinical variables and the primary endpoint is time to prostate cancer recurrence. We analyzed the prostate cancer data and evaluated prediction performance of several models based on the extended c statistic for censored data, showing that 1) the relationship between the clinical variable, prostate specific antigen, and the prostate cancer recurrence is likely nonlinear, i.e., the time to recurrence decreases as PSA increases and it starts to level off when PSA becomes greater than 11; 2) correct specification of this nonlinear effect improves performance in prediction and feature selection; and 3) addition of gene expression data does not seem to further improve the performance of the resultant risk

  4. Coverage-adjusted entropy estimation.

    PubMed

    Vu, Vincent Q; Yu, Bin; Kass, Robert E

    2007-09-20

    Data on 'neural coding' have frequently been analyzed using information-theoretic measures. These formulations involve the fundamental and generally difficult statistical problem of estimating entropy. We review briefly several methods that have been advanced to estimate entropy and highlight a method, the coverage-adjusted entropy estimator (CAE), due to Chao and Shen that appeared recently in the environmental statistics literature. This method begins with the elementary Horvitz-Thompson estimator, developed for sampling from a finite population, and adjusts for the potential new species that have not yet been observed in the sample-these become the new patterns or 'words' in a spike train that have not yet been observed. The adjustment is due to I. J. Good, and is called the Good-Turing coverage estimate. We provide a new empirical regularization derivation of the coverage-adjusted probability estimator, which shrinks the maximum likelihood estimate. We prove that the CAE is consistent and first-order optimal, with rate O(P)(1/log n), in the class of distributions with finite entropy variance and that, within the class of distributions with finite qth moment of the log-likelihood, the Good-Turing coverage estimate and the total probability of unobserved words converge at rate O(P)(1/(log n)(q)). We then provide a simulation study of the estimator with standard distributions and examples from neuronal data, where observations are dependent. The results show that, with a minor modification, the CAE performs much better than the MLE and is better than the best upper bound estimator, due to Paninski, when the number of possible words m is unknown or infinite. PMID:17567838

  5. Estimating risk.

    PubMed

    2016-07-01

    A free mobile phone app has been launched providing nurses and other hospital clinicians with a simple way to identify high-risk surgical patients. The app is a phone version of the Surgical Outcome Risk Tool (SORT), originally developed for online use with computers by researchers from the National Confidential Enquiry into Patient Outcome and Death and the University College London Hospital Surgical Outcomes Research Centre. SORT uses information about patients' health and planned surgical procedures to estimate the risk of death within 30 days of an operation. The percentages are only estimates, taking into account the general risks of the procedures and some information about patients, and should not be confused with patient-specific estimates in individual cases. PMID:27369709

  6. Severity of disease estimation and risk-adjustment for comparison of outcomes in mechanically ventilated patients using electronic routine care data.

    PubMed

    van Mourik, Maaike S M; Moons, Karel G M; Murphy, Michael V; Bonten, Marc J M; Klompas, Michael

    2015-07-01

    BACKGROUND Valid comparison between hospitals for benchmarking or pay-for-performance incentives requires accurate correction for underlying disease severity (case-mix). However, existing models are either very simplistic or require extensive manual data collection. OBJECTIVE To develop a disease severity prediction model based solely on data routinely available in electronic health records for risk-adjustment in mechanically ventilated patients. DESIGN Retrospective cohort study. PARTICIPANTS Mechanically ventilated patients from a single tertiary medical center (2006-2012). METHODS Predictors were extracted from electronic data repositories (demographic characteristics, laboratory tests, medications, microbiology results, procedure codes, and comorbidities) and assessed for feasibility and generalizability of data collection. Models for in-hospital mortality of increasing complexity were built using logistic regression. Estimated disease severity from these models was linked to rates of ventilator-associated events. RESULTS A total of 20,028 patients were initiated on mechanical ventilation, of whom 3,027 deceased in hospital. For models of incremental complexity, area under the receiver operating characteristic curve ranged from 0.83 to 0.88. A simple model including demographic characteristics, type of intensive care unit, time to intubation, blood culture sampling, 8 common laboratory tests, and surgical status achieved an area under the receiver operating characteristic curve of 0.87 (95% CI, 0.86-0.88) with adequate calibration. The estimated disease severity was associated with occurrence of ventilator-associated events. CONCLUSIONS Accurate estimation of disease severity in ventilated patients using electronic, routine care data was feasible using simple models. These estimates may be useful for risk-adjustment in ventilated patients. Additional research is necessary to validate and refine these models. PMID:25881675

  7. How should risk adjustment data be collected?

    PubMed

    Kessler, Daniel P

    2012-01-01

    Risk adjustment has broad general application and is a key part of the Patient Protection and Affordable Care Act (ACA). Yet, little has been written on how data required to support risk adjustment should be collected. This paper offers analytical support for a distributed approach, in which insurers retain possession of claims but pass on summary statistics to the risk adjustment authority as needed. It shows that distributed approaches function as well as or better than centralized ones-where insurers submit raw claims data to the risk adjustment authority-in terms of the goals of risk adjustment. In particular, it shows how distributed data analysis can be used to calibrate risk adjustment models and calculate payments, both in theory and in practice--drawing on the experience of distributed models in other contexts. In addition, it explains how distributed methods support other goals of the ACA, and can support projects requiring data aggregation more generally. It concludes that states should seriously consider distributed methods to implement their risk adjustment programs. PMID:22931020

  8. Risk-adjusted monitoring of survival times

    SciTech Connect

    Sego, Landon H.; Reynolds, Marion R.; Woodall, William H.

    2009-02-26

    We consider the monitoring of clinical outcomes, where each patient has a di®erent risk of death prior to undergoing a health care procedure.We propose a risk-adjusted survival time CUSUM chart (RAST CUSUM) for monitoring clinical outcomes where the primary endpoint is a continuous, time-to-event variable that may be right censored. Risk adjustment is accomplished using accelerated failure time regression models. We compare the average run length performance of the RAST CUSUM chart to the risk-adjusted Bernoulli CUSUM chart, using data from cardiac surgeries to motivate the details of the comparison. The comparisons show that the RAST CUSUM chart is more efficient at detecting a sudden decrease in the odds of death than the risk-adjusted Bernoulli CUSUM chart, especially when the fraction of censored observations is not too high. We also discuss the implementation of a prospective monitoring scheme using the RAST CUSUM chart.

  9. Overpaying morbidity adjusters in risk equalization models.

    PubMed

    van Kleef, R C; van Vliet, R C J A; van de Ven, W P M M

    2016-09-01

    Most competitive social health insurance markets include risk equalization to compensate insurers for predictable variation in healthcare expenses. Empirical literature shows that even the most sophisticated risk equalization models-with advanced morbidity adjusters-substantially undercompensate insurers for selected groups of high-risk individuals. In the presence of premium regulation, these undercompensations confront consumers and insurers with incentives for risk selection. An important reason for the undercompensations is that not all information with predictive value regarding healthcare expenses is appropriate for use as a morbidity adjuster. To reduce incentives for selection regarding specific groups we propose overpaying morbidity adjusters that are already included in the risk equalization model. This paper illustrates the idea of overpaying by merging data on morbidity adjusters and healthcare expenses with health survey information, and derives three preconditions for meaningful application. Given these preconditions, we think overpaying may be particularly useful for pharmacy-based cost groups. PMID:26420555

  10. Implementation of Risk Adjustment for Medicare

    PubMed Central

    Ingber, Melvin J.

    2000-01-01

    The Health Care Financing Administration (HCFA) implemented risk adjustment for Medicare capitated organizations January 2000. The risk adjustment system used, the Principal Inpatient Diagnostic Cost Group (PIPDCG) method, had to be incorporated into the payment structure mandated by the Balanced Budget Act of 1997 (BBA). This article describes how risk adjustment was integrated into the payment system within the rules of the BBA, and how fee-for-service (FFS) and health maintenance organization (HMO) data are collected and used in the determination of payment. PMID:11481750

  11. 45 CFR 153.350 - Risk adjustment data validation standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.350 Risk adjustment...

  12. 45 CFR 153.350 - Risk adjustment data validation standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.350 Risk adjustment...

  13. Estimating the Roles of Genetic Risk, Perinatal Risk, and Marital Hostility on Early Childhood Adjustment: Medical Records and Self-Reports.

    PubMed

    Neiderhiser, Jenae M; Marceau, Kristine; De Araujo-Greecher, Marielena; Ganiban, Jody M; Mayes, Linda C; Shaw, Daniel S; Reiss, David; Leve, Leslie D

    2016-05-01

    A wide variety of perinatal risk factors have been linked to later developmental outcomes in children. Much of this work has relied on either birth/medical records or mothers' self-reports collected after delivery, and there has been an ongoing debate about which strategy provides the most accurate and reliable data. This report uses a parent-offspring adoption design (N = 561 families) to (1) examine the correspondence between medical record data and self-report data, (2) examine how perinatal risk factors may influence child internalizing and externalizing behavior at age 4.5 years, and (3) explore interactions among genetic, perinatal risk, and rearing environment on child internalizing and externalizing behavior during early childhood. The agreement of self-reports and medical records data was relatively high (51-100 %), although there was some variation based on the construct. There were few main effects of perinatal risk on child outcomes; however, there were several 2- and 3-way interactions suggesting that the combined influences of genetic, perinatal, and rearing environmental risks are important, particularly for predicting whether children exhibit internalizing versus externalizing symptoms at age 4.5 years. PMID:27075497

  14. 42 CFR 422.310 - Risk adjustment data.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 3 2014-10-01 2014-10-01 false Risk adjustment data. 422.310 Section 422.310... Organizations § 422.310 Risk adjustment data. (a) Definition of risk adjustment data. Risk adjustment data are all data that are used in the development and application of a risk adjustment payment model. (b)...

  15. 42 CFR 422.310 - Risk adjustment data.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 3 2012-10-01 2012-10-01 false Risk adjustment data. 422.310 Section 422.310... Organizations § 422.310 Risk adjustment data. (a) Definition of risk adjustment data. Risk adjustment data are all data that are used in the development and application of a risk adjustment payment model. (b)...

  16. 42 CFR 422.310 - Risk adjustment data.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Risk adjustment data. 422.310 Section 422.310....310 Risk adjustment data. (a) Definition of risk adjustment data. Risk adjustment data are all data that are used in the development and application of a risk adjustment payment model. (b)...

  17. Risk adjustment for pediatric quality indicators.

    PubMed

    Kuhlthau, Karen; Ferris, Timothy G G; Iezzoni, Lisa I

    2004-01-01

    The movement to measure medical care quality has been accelerating, spurred on by evidence of poor quality of care and trials of interventions to improve care. Appropriate measurement of quality of care is an essential aspect of improving the quality of care, yet some quality measures may be influenced by patients' attributes unrelated to quality of care. Risk adjustment is the term commonly applied to those methods that account for patient-related attributes, making measurement of health care quality as comparable as possible across providers or organizations seeing different mixes of patients. The measurement of quality of care for children poses specific challenges. In addition to these measurement challenges, analysts must ensure that quality comparisons among doctors, groups of doctors, hospitals, or health plans are not adversely affected by the likelihood that different types of patients seek care in different places. Although some techniques designed to adjust performance measures for case mix were developed for both adults and children, other systems are specific to childhood circumstances. The theoretical issues involved in risk-adjusting childhood outcomes measures for newborns in the neonatal intensive care unit were reviewed recently. Here, we go beyond the neonatal intensive care unit setting to consider risk adjustment for pediatric quality measures more broadly. In particular, we 1) review the conceptual background for risk-adjusting quality measures, 2) present policy issues related to adjusting pediatric quality measures, and 3) catalog existing risk-adjustment methodologies for pediatric quality measures. We conclude with an overall assessment of the status of risk adjustment for pediatric quality measures and recommendations for additional research and application. PMID:14702503

  18. Risk adjustment for a children's capitation rate.

    PubMed

    Newhouse, J P; Sloss, E M; Manning, W G; Keeler, E B

    1993-01-01

    Few capitation arrangements vary premiums by a child's health characteristics, yielding an incentive to discriminate against children with predictably high expenditures from chronic diseases. In this article, we explore risk adjusters for the 35 percent of the variance in annual out-patient expenditure we find to be potentially predictable. Demographic factors such as age and gender only explain 5 percent of such variance; health status measures explain 25 percent, prior use and health status measures together explain 65 to 70 percent. The profit from risk selection falls less than proportionately with improved ability to adjust for risk. Partial capitation rates may be necessary to mitigate skimming and dumping. PMID:10133708

  19. Radiation risk estimation models

    SciTech Connect

    Hoel, D.G.

    1987-11-01

    Cancer risk models and their relationship to ionizing radiation are discussed. There are many model assumptions and risk factors that have a large quantitative impact on the cancer risk estimates. Other health end points such as mental retardation may be an even more serious risk than cancer for those with in utero exposures. 8 references.

  20. 45 CFR 153.350 - Risk adjustment data validation standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... implementation of any risk adjustment software and ensure proper validation of a statistically valid sample of... respect to implementation of risk adjustment software or as a result of data validation conducted pursuant... implementation of risk adjustment software or data validation....

  1. Affordable Care Act risk adjustment: overview, context, and challenges.

    PubMed

    Kautter, John; Pope, Gregory C; Keenan, Patricia

    2014-01-01

    Beginning in 2014, individuals and small businesses will be able to purchase private health insurance through competitive marketplaces. The Affordable Care Act (ACA) provides for a program of risk adjustment in the individual and small group markets in 2014 as Marketplaces are implemented and new market reforms take effect. The purpose of risk adjustment is to lessen or eliminate the influence of risk selection on the premiums that plans charge and the incentive for plans to avoid sicker enrollees. This article--the first of three in the Medicare & Medicaid Research Review--describes the key program goal and issues in the Department of Health and Human Services (HHS) developed risk adjustment methodology, and identifies key choices in how the methodology responds to these issues. The goal of the HHS risk adjustment methodology is to compensate health insurance plans for differences in enrollee health mix so that plan premiums reflect differences in scope of coverage and other plan factors, but not differences in health status. The methodology includes a risk adjustment model and a risk transfer formula that together address this program goal as well as three issues specific to ACA risk adjustment: 1) new population; 2) cost and rating factors; and 3) balanced transfers within state/market. The risk adjustment model, described in the second article, estimates differences in health risks taking into account the new population and scope of coverage (actuarial value level). The transfer formula, described in the third article, calculates balanced transfers that are intended to account for health risk differences while preserving permissible premium differences. PMID:25364625

  2. 45 CFR 153.310 - Risk adjustment administration.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false Risk adjustment administration. 153.310 Section... ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.310 Risk adjustment...

  3. 45 CFR 153.310 - Risk adjustment administration.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 1 2013-10-01 2013-10-01 false Risk adjustment administration. 153.310 Section... ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.310 Risk adjustment...

  4. Adjusting Population Risk for Functional Health Status.

    PubMed

    Fuller, Richard L; Hughes, John S; Goldfield, Norbert I

    2016-04-01

    Risk adjustment accounts for differences in population mix by reducing the likelihood of enrollee selection by managed care plans and providing a correction to otherwise biased reporting of provider or plan performance. Functional health status is not routinely included within risk-adjustment methods, but is believed by many to be a significant enhancement to risk adjustment for complex enrollees and patients. In this analysis a standardized measure of functional health was created using 3 different source functional assessment instruments submitted to the Medicare program on condition of payment. The authors use a 5% development sample of Medicare claims from 2006 and 2007, including functional health assessments, and develop a model of functional health classification comprising 9 groups defined by the interaction of self-care, mobility, incontinence, and cognitive impairment. The 9 functional groups were used to augment Clinical Risk Groups, a diagnosis-based patient classification system, and when using a validation set of 100% of Medicare data for 2010 and 2011, this study found the use of the functional health module to improve the fit of observed enrollee cost, measured by the R(2) statistic, by 5% across all Medicare enrollees. The authors observed complex nonlinear interactions across functional health domains when constructing the model and caution that functional health status needs careful handling when used for risk adjustment. The addition of functional health status within existing risk-adjustment models has the potential to improve equitable resource allocation in the financing of care costs for more complex enrollees if handled appropriately. (Population Health Management 2016;19:136-144). PMID:26348621

  5. Radiations in space: risk estimates.

    PubMed

    Fry, R J M

    2002-01-01

    The complexity of radiation environments in space makes estimation of risks more difficult than for the protection of terrestrial populations. In deep space the duration of the mission, position in the solar cycle, number and size of solar particle events (SPE) and the spacecraft shielding are the major determinants of risk. In low-earth orbit missions there are the added factors of altitude and orbital inclination. Different radiation qualities such as protons and heavy ions and secondary radiations inside the spacecraft such as neutrons of various energies, have to be considered. Radiation dose rates in space are low except for short periods during very large SPEs. Risk estimation for space activities is based on the human experience of exposure to gamma rays and to a lesser extent X rays. The doses of protons, heavy ions and neutrons are adjusted to take into account the relative biological effectiveness (RBE) of the different radiation types and thus derive equivalent doses. RBE values and factors to adjust for the effect of dose rate have to be obtained from experimental data. The influence of age and gender on the cancer risk is estimated from the data from atomic bomb survivors. Because of the large number of variables the uncertainities in the probability of the effects are large. Information needed to improve the risk estimates includes: (1) risk of cancer induction by protons, heavy ions and neutrons: (2) influence of dose rate and protraction, particularly on potential tissue effects such as reduced fertility and cataracts: and (3) possible effects of heavy ions on the central nervous system. Risk cannot be eliminated and thus there must be a consensus on what level of risk is acceptable. PMID:12382925

  6. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Adjustments to agreement estimate. 100.19..., COMMUNICATIONS ASSISTANCE FOR LAW ENFORCEMENT ACT OF 1994 § 100.19 Adjustments to agreement estimate. (a... the adjustment results in an increase in the estimated reimbursement, the FBI will review...

  7. 42 CFR 403.750 - Estimate of expenditures and adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Estimate of expenditures and adjustments. 403.750...-Benefits, Conditions of Participation, and Payment § 403.750 Estimate of expenditures and adjustments. (a) Estimates. CMS estimates the level of expenditures for services provided under this subpart before the...

  8. 45 CFR 153.320 - Federally certified risk adjustment methodology.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.320 Federally certified...

  9. 45 CFR 153.610 - Risk adjustment issuer requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT Health Insurance Issuer Standards Related to the Risk Adjustment Program § 153.610...

  10. 45 CFR 153.620 - Compliance with risk adjustment standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT Health Insurance Issuer Standards Related to the Risk Adjustment Program § 153.620...

  11. 45 CFR 153.620 - Compliance with risk adjustment standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT Health Insurance Issuer Standards Related to the Risk Adjustment Program § 153.620...

  12. Risk-Adjusted Models for Adverse Obstetric Outcomes and Variation in Risk Adjusted Outcomes Across Hospitals

    PubMed Central

    Bailit, Jennifer L.; Grobman, William A.; Rice, Madeline Murguia; Spong, Catherine Y.; Wapner, Ronald J.; Varner, Michael W.; Thorp, John M.; Leveno, Kenneth J.; Caritis, Steve N.; Shubert, Phillip J.; Tita, Alan T. N.; Saade, George; Sorokin, Yoram; Rouse, Dwight J.; Blackwell, Sean C.; Tolosa, Jorge E.; Van Dorsten, J. Peter

    2014-01-01

    Objective Regulatory bodies and insurers evaluate hospital quality using obstetrical outcomes, however meaningful comparisons should take pre-existing patient characteristics into account. Furthermore, if risk-adjusted outcomes are consistent within a hospital, fewer measures and resources would be needed to assess obstetrical quality. Our objective was to establish risk-adjusted models for five obstetric outcomes and assess hospital performance across these outcomes. Study Design A cohort study of 115,502 women and their neonates born in 25 hospitals in the United States between March 2008 and February 2011. Hospitals were ranked according to their unadjusted and risk-adjusted frequency of venous thromboembolism, postpartum hemorrhage, peripartum infection, severe perineal laceration, and a composite neonatal adverse outcome. Correlations between hospital risk-adjusted outcome frequencies were assessed. Results Venous thromboembolism occurred too infrequently (0.03%, 95% CI 0.02% – 0.04%) for meaningful assessment. Other outcomes occurred frequently enough for assessment (postpartum hemorrhage 2.29% (95% CI 2.20–2.38), peripartum infection 5.06% (95% CI 4.93–5.19), severe perineal laceration at spontaneous vaginal delivery 2.16% (95% CI 2.06–2.27), neonatal composite 2.73% (95% CI 2.63–2.84)). Although there was high concordance between unadjusted and adjusted hospital rankings, several individual hospitals had an adjusted rank that was substantially different (as much as 12 rank tiers) than their unadjusted rank. None of the correlations between hospital adjusted outcome frequencies was significant. For example, the hospital with the lowest adjusted frequency of peripartum infection had the highest adjusted frequency of severe perineal laceration. Conclusions Evaluations based on a single risk-adjusted outcome cannot be generalized to overall hospital obstetric performance. PMID:23891630

  13. 45 CFR 153.310 - Risk adjustment administration.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 153.310 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES REQUIREMENTS RELATING TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.310 Risk adjustment...

  14. 45 CFR 153.330 - State alternate risk adjustment methodology.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false State alternate risk adjustment methodology. 153... HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.330 State alternate...

  15. 45 CFR 153.320 - Federally certified risk adjustment methodology.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 1 2013-10-01 2013-10-01 false Federally certified risk adjustment methodology... TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.320 Federally certified...

  16. Injury Risk Estimation Expertise

    PubMed Central

    Petushek, Erich J.; Ward, Paul; Cokely, Edward T.; Myer, Gregory D.

    2015-01-01

    Background: Simple observational assessment of movement is a potentially low-cost method for anterior cruciate ligament (ACL) injury screening and prevention. Although many individuals utilize some form of observational assessment of movement, there are currently no substantial data on group skill differences in observational screening of ACL injury risk. Purpose/Hypothesis: The purpose of this study was to compare various groups’ abilities to visually assess ACL injury risk as well as the associated strategies and ACL knowledge levels. The hypothesis was that sports medicine professionals would perform better than coaches and exercise science academics/students and that these subgroups would all perform better than parents and other general population members. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 428 individuals, including physicians, physical therapists, athletic trainers, strength and conditioning coaches, exercise science researchers/students, athletes, parents, and members of the general public participated in the study. Participants completed the ACL Injury Risk Estimation Quiz (ACL-IQ) and answered questions related to assessment strategy and ACL knowledge. Results: Strength and conditioning coaches, athletic trainers, physical therapists, and exercise science students exhibited consistently superior ACL injury risk estimation ability (+2 SD) as compared with sport coaches, parents of athletes, and members of the general public. The performance of a substantial number of individuals in the exercise sciences/sports medicines (approximately 40%) was similar to or exceeded clinical instrument-based biomechanical assessment methods (eg, ACL nomogram). Parents, sport coaches, and the general public had lower ACL-IQ, likely due to their lower ACL knowledge and to rating the importance of knee/thigh motion lower and weight and jump height higher. Conclusion: Substantial cross-professional/group differences in visual ACL

  17. Risk adjustment: where are we now?

    PubMed

    Newhouse, J P

    1998-01-01

    Risk adjustment is intended to minimize selection of patients or enrollees in health plans. Current efforts generally are recognized as inadequate, but improvement is difficult. The greatest short-term gain will come from introducing diagnostic information, though outpatient diagnosis data are unreliable. Initial efforts may use inpatient data, but this creates incentives to hospitalize people. Even exploiting diagnosis information leaves substantial imperfections. Partial capitation, common in behavioral health, reduces incentives to select patients and stent on services, but current policy resists it, perhaps because policymakers misinterpret the lesson of the Prospective Payment System. Theoretically, not paying plans more for providing additional services is optimal only if consumers are well informed. PMID:9719781

  18. 45 CFR 153.330 - State alternate risk adjustment methodology.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.330 State alternate risk... methodology: (i) Accurately explains the variation in health care costs of a given population; (ii) Links...

  19. 45 CFR 153.330 - State alternate risk adjustment methodology.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.330 State alternate risk... methodology: (i) Accurately explains the variation in health care costs of a given population; (ii) Links...

  20. On variance estimate for covariate adjustment by propensity score analysis.

    PubMed

    Zou, Baiming; Zou, Fei; Shuster, Jonathan J; Tighe, Patrick J; Koch, Gary G; Zhou, Haibo

    2016-09-10

    Propensity score (PS) methods have been used extensively to adjust for confounding factors in the statistical analysis of observational data in comparative effectiveness research. There are four major PS-based adjustment approaches: PS matching, PS stratification, covariate adjustment by PS, and PS-based inverse probability weighting. Though covariate adjustment by PS is one of the most frequently used PS-based methods in clinical research, the conventional variance estimation of the treatment effects estimate under covariate adjustment by PS is biased. As Stampf et al. have shown, this bias in variance estimation is likely to lead to invalid statistical inference and could result in erroneous public health conclusions (e.g., food and drug safety and adverse events surveillance). To address this issue, we propose a two-stage analytic procedure to develop a valid variance estimator for the covariate adjustment by PS analysis strategy. We also carry out a simple empirical bootstrap resampling scheme. Both proposed procedures are implemented in an R function for public use. Extensive simulation results demonstrate the bias in the conventional variance estimator and show that both proposed variance estimators offer valid estimates for the true variance, and they are robust to complex confounding structures. The proposed methods are illustrated for a post-surgery pain study. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26999553

  1. 45 CFR 153.340 - Data collection under risk adjustment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 1 2012-10-01 2012-10-01 false Data collection under risk adjustment. 153.340 Section 153.340 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES REQUIREMENTS RELATING TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the...

  2. 12 CFR 615.5210 - Risk-adjusted assets.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Risk-adjusted assets. 615.5210 Section 615.5210... POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5210 Risk-adjusted assets. (a... appropriate credit conversion factor in § 615.5212, is assigned to one of the risk categories specified...

  3. 12 CFR 615.5210 - Risk-adjusted assets.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Risk-adjusted assets. 615.5210 Section 615.5210... POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5210 Risk-adjusted assets. (a... appropriate credit conversion factor in § 615.5212, is assigned to one of the risk categories specified...

  4. 12 CFR 615.5210 - Risk-adjusted assets.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Risk-adjusted assets. 615.5210 Section 615.5210... POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5210 Risk-adjusted assets. (a... appropriate credit conversion factor in § 615.5212, is assigned to one of the risk categories specified...

  5. 12 CFR 615.5210 - Risk-adjusted assets.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Risk-adjusted assets. 615.5210 Section 615.5210... POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5210 Risk-adjusted assets. (a... appropriate credit conversion factor in § 615.5212, is assigned to one of the risk categories specified...

  6. 45 CFR 153.610 - Risk adjustment issuer requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... or a plan not subject to 45 CFR 147.102, 147.104, 147.106, 156.80, and subpart B of part 156) must... 45 Public Welfare 1 2013-10-01 2013-10-01 false Risk adjustment issuer requirements. 153.610... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE...

  7. 45 CFR 153.610 - Risk adjustment issuer requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... or a plan not subject to 45 CFR 147.102, 147.104, 147.106, 156.80, and subpart B of part 156) must... 45 Public Welfare 1 2014-10-01 2014-10-01 false Risk adjustment issuer requirements. 153.610... CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE...

  8. Change point detection in risk adjusted control charts.

    PubMed

    Assareh, Hassan; Smith, Ian; Mengersen, Kerrie

    2015-12-01

    Precise identification of the time when a change in a clinical process has occurred enables experts to identify a potential special cause more effectively. In this article, we develop change point estimation methods for a clinical dichotomous process in the presence of case mix. We apply Bayesian hierarchical models to formulate the change point where there exists a step change in the odds ratio and logit of risk of a Bernoulli process. Markov Chain Monte Carlo is used to obtain posterior distributions of the change point parameters including location and magnitude of changes and also corresponding probabilistic intervals and inferences. The performance of the Bayesian estimator is investigated through simulations and the result shows that precise estimates can be obtained when they are used in conjunction with the risk-adjusted CUSUM and EWMA control charts. In comparison with alternative EWMA and CUSUM estimators, more accurate and precise estimates are obtained by the Bayesian estimator. These superiorities enhance when probability quantification, flexibility and generaliability of the Bayesian change point detection model are also considered. The Deviance Information Criterion, as a model selection criterion in the Bayesian context, is applied to find the best change point model for a given dataset where there is no prior knowledge about the change type in the process. PMID:22025415

  9. Risk-adjusted monitoring of binary surgical outcomes.

    PubMed

    Steiner, S H; Cook, R J; Farewell, V T

    2001-01-01

    A graphical procedure suitable for prospectively monitoring surgical performance is proposed. The approach is based on accumulating evidence from the outcomes of all previous surgical patients in a series using a new type of cumulative sum chart. Cumulative sum procedures are designed to "signal" if sufficient evidence has accumulated that the surgical failure rate has changed substantially. In this way, the chart rapidly detects deterioration (or improvement) in surgical performance while not overreacting to the expected fluctuations due to chance. Through the use of a likelihood-based scoring method, the cumulative sum procedure is adapted so that it adjusts for the surgical risk of each patient estimated preoperatively. The procedure is therefore applicable in situations where it is desirable to adjust for a mix of patients. Signals of the chart lead to investigations of the cause and to the timely introduction of remedial measures designed to avoid unnecessary future failures. PMID:11386623

  10. 77 FR 21775 - Risk Adjustment Meeting-May 7, 2012 and May 8, 2012

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-11

    ... following topics: The risk adjustment model, calculation of plan average actuarial risk, calculation of... risk adjustment model, calculation of plan average actuarial risk, calculation of payments and...

  11. 12 CFR 615.5210 - Risk-adjusted assets.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Risk-adjusted assets. 615.5210 Section 615.5210 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN POLICIES AND OPERATIONS, AND FUNDING OPERATIONS Capital Adequacy § 615.5210 Risk-adjusted assets. (a) Computation. Each asset on the...

  12. A clinical economics workstation for risk-adjusted health care cost management.

    PubMed Central

    Eisenstein, E. L.; Hales, J. W.

    1995-01-01

    This paper describes a healthcare cost accounting system which is under development at Duke University Medical Center. Our approach differs from current practice in that this system will dynamically adjust its resource usage estimates to compensate for variations in patient risk levels. This adjustment is made possible by introducing a new cost accounting concept, Risk-Adjusted Quantity (RQ). RQ divides case-level resource usage variances into their risk-based component (resource consumption differences attributable to differences in patient risk levels) and their non-risk-based component (resource consumption differences which cannot be attributed to differences in patient risk levels). Because patient risk level is a factor in estimating resource usage, this system is able to simultaneously address the financial and quality dimensions of case cost management. In effect, cost-effectiveness analysis is incorporated into health care cost management. PMID:8563361

  13. Do insurers respond to risk adjustment? A long-term, nationwide analysis from Switzerland.

    PubMed

    von Wyl, Viktor; Beck, Konstantin

    2016-03-01

    Community rating in social health insurance calls for risk adjustment in order to eliminate incentives for risk selection. Swiss risk adjustment is known to be insufficient, and substantial risk selection incentives remain. This study develops five indicators to monitor residual risk selection. Three indicators target activities of conglomerates of insurers (with the same ownership), which steer enrollees into specific carriers based on applicants' risk profiles. As a proxy for their market power, those indicators estimate the amount of premium-, health care cost-, and risk-adjustment transfer variability that is attributable to conglomerates. Two additional indicators, derived from linear regression, describe the amount of residual cost differences between insurers that are not covered by risk adjustment. All indicators measuring conglomerate-based risk selection activities showed increases between 1996 and 2009, paralleling the establishment of new conglomerates. At their maxima in 2009, the indicator values imply that 56% of the net risk adjustment volume, 34% of premium variability, and 51% cost variability in the market were attributable to conglomerates. From 2010 onwards, all indicators decreased, coinciding with a pre-announced risk adjustment reform implemented in 2012. Likewise, the regression-based indicators suggest that the volume and variance of residual cost differences between insurers that are not equaled out by risk adjustment have decreased markedly since 2009 as a result of the latest reform. Our analysis demonstrates that risk-selection, especially by conglomerates, is a real phenomenon in Switzerland. However, insurers seem to have reduced risk selection activities to optimize their losses and gains from the latest risk adjustment reform. PMID:25663430

  14. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the FBI when any change affecting the level of reimbursement occurs. (2) Upon such notification, if the adjustment results in an increase in the estimated reimbursement, the FBI will review the... expenditure. (3) The FBI will provide the decision as to the acceptability of any increase to the carrier...

  15. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the FBI when any change affecting the level of reimbursement occurs. (2) Upon such notification, if the adjustment results in an increase in the estimated reimbursement, the FBI will review the... expenditure. (3) The FBI will provide the decision as to the acceptability of any increase to the carrier...

  16. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the FBI when any change affecting the level of reimbursement occurs. (2) Upon such notification, if the adjustment results in an increase in the estimated reimbursement, the FBI will review the... expenditure. (3) The FBI will provide the decision as to the acceptability of any increase to the carrier...

  17. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the FBI when any change affecting the level of reimbursement occurs. (2) Upon such notification, if the adjustment results in an increase in the estimated reimbursement, the FBI will review the... expenditure. (3) The FBI will provide the decision as to the acceptability of any increase to the carrier...

  18. [Estimation of risk areas for hepatitis A].

    PubMed

    Braga, Ricardo Cerqueira Campos; Valencia, Luís Iván Ortiz; Medronho, Roberto de Andrade; Escosteguy, Claudia Caminha

    2008-08-01

    This study estimated hepatitis A risk areas in a region of Duque de Caxias, Rio de Janeiro State, Brazil. A cross-sectional study consisting of a hepatitis A serological survey and a household survey were conducted in 19 census tracts. Of these, 11 tracts were selected and 1,298 children from one to ten years of age were included in the study. Geostatistical techniques allowed modeling the spatial continuity of hepatitis A, non-use of filtered drinking water, time since installation of running water, and number of water taps per household and their spatial estimation through ordinary and indicator kriging. Adjusted models for the outcome and socioeconomic variables were isotropic; risk maps were constructed; cross-validation of the four models was satisfactory. Spatial estimation using the kriging method detected areas with increased risk of hepatitis A, independently of the urban administrative area in which the census tracts were located. PMID:18709215

  19. 45 CFR 153.365 - General oversight requirements for State-operated risk adjustment programs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Services REQUIREMENTS RELATING TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment...

  20. Children's Adjustment Following Divorce: Risk and Resilience Perspectives.

    ERIC Educational Resources Information Center

    Kelly, Joan B.; Emery, Robert E.

    2003-01-01

    Reviews the empirical literature on the longer-term adjustment of children of divorce from the perspective of (a) the stressors and elevated risks that divorce presents for children and (b) protective factors associated with better adjustment. The resiliency demonstrated by the majority of children is discussed, as are controversies regarding the…

  1. Social Cognition and Adjustment in Children at Risk for Psychopathology.

    ERIC Educational Resources Information Center

    Downey, Geraldine; Walker, Elaine

    1989-01-01

    Tested 2 models of the effect of social cognition on the link between child adjustment and the 2 family risk factors of maltreatment and parental psychopathology. In 83 subjects of 7-14 years, maltreatment predicted aggression and peer rejection, but parental psychopathology did not. Adjustment of subjects with a disturbed parent depended on…

  2. 42 CFR 422.310 - Risk adjustment data.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... all data that are used in the development and application of a risk adjustment payment model. (b) Data... quality review and improvement activities, and for Medicare coverage purposes. (g) Deadlines...

  3. Lasso adjustments of treatment effect estimates in randomized experiments

    PubMed Central

    Bloniarz, Adam; Liu, Hanzhong; Zhang, Cun-Hui; Sekhon, Jasjeet S.; Yu, Bin

    2016-01-01

    We provide a principled way for investigators to analyze randomized experiments when the number of covariates is large. Investigators often use linear multivariate regression to analyze randomized experiments instead of simply reporting the difference of means between treatment and control groups. Their aim is to reduce the variance of the estimated treatment effect by adjusting for covariates. If there are a large number of covariates relative to the number of observations, regression may perform poorly because of overfitting. In such cases, the least absolute shrinkage and selection operator (Lasso) may be helpful. We study the resulting Lasso-based treatment effect estimator under the Neyman–Rubin model of randomized experiments. We present theoretical conditions that guarantee that the estimator is more efficient than the simple difference-of-means estimator, and we provide a conservative estimator of the asymptotic variance, which can yield tighter confidence intervals than the difference-of-means estimator. Simulation and data examples show that Lasso-based adjustment can be advantageous even when the number of covariates is less than the number of observations. Specifically, a variant using Lasso for selection and ordinary least squares (OLS) for estimation performs particularly well, and it chooses a smoothing parameter based on combined performance of Lasso and OLS. PMID:27382153

  4. Lasso adjustments of treatment effect estimates in randomized experiments.

    PubMed

    Bloniarz, Adam; Liu, Hanzhong; Zhang, Cun-Hui; Sekhon, Jasjeet S; Yu, Bin

    2016-07-01

    We provide a principled way for investigators to analyze randomized experiments when the number of covariates is large. Investigators often use linear multivariate regression to analyze randomized experiments instead of simply reporting the difference of means between treatment and control groups. Their aim is to reduce the variance of the estimated treatment effect by adjusting for covariates. If there are a large number of covariates relative to the number of observations, regression may perform poorly because of overfitting. In such cases, the least absolute shrinkage and selection operator (Lasso) may be helpful. We study the resulting Lasso-based treatment effect estimator under the Neyman-Rubin model of randomized experiments. We present theoretical conditions that guarantee that the estimator is more efficient than the simple difference-of-means estimator, and we provide a conservative estimator of the asymptotic variance, which can yield tighter confidence intervals than the difference-of-means estimator. Simulation and data examples show that Lasso-based adjustment can be advantageous even when the number of covariates is less than the number of observations. Specifically, a variant using Lasso for selection and ordinary least squares (OLS) for estimation performs particularly well, and it chooses a smoothing parameter based on combined performance of Lasso and OLS. PMID:27382153

  5. AAHKS Risk Adjustment Initiative: Why Is It Important?

    PubMed

    Fehring, Thomas K

    2016-06-01

    Risk adjustment is critical when any comparison of hospital performance or surgeon performance on patient outcomes is being measured. The purpose of risk adjustment is to level the playing field in making comparisons of outcome either against the benchmark or across individual providers, hospitals, or provider groups. The consequences of not leveling the playing field may lead to the inappropriate inference of high quality, that is outcomes are better not because of better quality but because the patients are healthy. Additional consequence of not leveling the playing field is the inappropriate inference of low quality, that is outcomes are worse not because of lower quality but because patients are less healthy at the onset. Therefore, it is critically important that risk adjustment is done properly so that access for the patients with the most severe problems will be maintained. Surgeons and hospitals should not be discouraged from providing care for these individuals for fear of publicly reporting outcomes that are not properly risk adjusted. To that end, American Association of Hip and Knee Surgeons created a Risk Adjustment Task Force to collaborate with Center for Medicare and Medicaid Services in creating a more robust risk adjustment model to take into account clinical factors and severity of orthopedic disease. PMID:27157277

  6. Reinforcing flood-risk estimation.

    PubMed

    Reed, Duncan W

    2002-07-15

    Flood-frequency estimation is inherently uncertain. The practitioner applies a combination of gauged data, scientific method and hydrological judgement to derive a flood-frequency curve for a particular site. The resulting estimate can be thought fully satisfactory only if it is broadly consistent with all that is reliably known about the flood-frequency behaviour of the river. The paper takes as its main theme the search for information to strengthen a flood-risk estimate made from peak flows alone. Extra information comes in many forms, including documentary and monumental records of historical floods, and palaeological markers. Meteorological information is also useful, although rainfall rarity is difficult to assess objectively and can be a notoriously unreliable indicator of flood rarity. On highly permeable catchments, groundwater levels present additional data. Other types of information are relevant to judging hydrological similarity when the flood-frequency estimate derives from data pooled across several catchments. After highlighting information sources, the paper explores a second theme: that of consistency in flood-risk estimates. Following publication of the Flood estimation handbook, studies of flood risk are now using digital catchment data. Automated calculation methods allow estimates by standard methods to be mapped basin-wide, revealing anomalies at special sites such as river confluences. Such mapping presents collateral information of a new character. Can this be used to achieve flood-risk estimates that are coherent throughout a river basin? PMID:12804255

  7. Integrating Risk Adjustment and Enrollee Premiums in Health Plan Payment

    PubMed Central

    McGuire, Thomas G.; Glazer, Jacob; Newhouse, Joseph P.; Normand, Sharon-Lise; Shi, Julie; Sinaiko, Anna D.; Zuvekas, Samuel

    2013-01-01

    In two important health policy contexts – private plans in Medicare and the new state-run “Exchanges” created as part of the Affordable Care Act (ACA) – plan payments come from two sources: risk-adjusted payments from a Regulator and premiums charged to individual enrollees. This paper derives principles for integrating risk-adjusted payments and premium policy in individual health insurance markets based on fitting total plan payments to health plan costs per person as closely as possible. A least squares regression including both health status and variables used in premiums reveals the weights a Regulator should put on risk adjusters when markets determine premiums. We apply the methods to an Exchange-eligible population drawn from the Medical Expenditure Panel Survey (MEPS). PMID:24308878

  8. Risk adjusting capitation: applications in employed and disabled populations.

    PubMed

    Madden, C W; Mackay, B P; Skillman, S M; Ciol, M; Diehr, P K

    2000-02-01

    Risk adjustment may be a sensible strategy to reduce selection bias because it links managed care payment directly to the costs of providing services. In this paper we compare risk adjustment models in two populations (public employees and their dependents, and publicly-insured low income individuals with disabilities) in Washington State using two statistical approaches and three health status measures. We conclude that a two-part logistic/GLM statistical model performs better in populations with large numbers of individuals who do not use health services. This model was successfully implemented in the employed population, but the managed care program for the publicly insured population was terminated before risk adjustment could be applied. The choice of the most appropriate health status measure depends on purchasers' principles and desired outcomes. PMID:10780278

  9. Integrating risk adjustment and enrollee premiums in health plan payment.

    PubMed

    McGuire, Thomas G; Glazer, Jacob; Newhouse, Joseph P; Normand, Sharon-Lise; Shi, Julie; Sinaiko, Anna D; Zuvekas, Samuel H

    2013-12-01

    In two important health policy contexts - private plans in Medicare and the new state-run "Exchanges" created as part of the Affordable Care Act (ACA) - plan payments come from two sources: risk-adjusted payments from a Regulator and premiums charged to individual enrollees. This paper derives principles for integrating risk-adjusted payments and premium policy in individual health insurance markets based on fitting total plan payments to health plan costs per person as closely as possible. A least squares regression including both health status and variables used in premiums reveals the weights a Regulator should put on risk adjusters when markets determine premiums. We apply the methods to an Exchange-eligible population drawn from the Medical Expenditure Panel Survey (MEPS). PMID:24308878

  10. Risk-adjusted outcomes in Medicare inpatient nephrectomy patients.

    PubMed

    Fry, Donald E; Pine, Michael; Nedza, Susan M; Locke, David G; Reband, Agnes M; Pine, Gregory

    2016-09-01

    Without risk-adjusted outcomes of surgical care across both the inpatient and postacute period of time, hospitals and surgeons cannot evaluate the effectiveness of current performance in nephrectomy and other operations, and will not have objective metrics to gauge improvements from care redesign efforts.We compared risk-adjusted hospital outcomes following elective total and partial nephrectomy to demonstrate differences that can be used to improve care. We used the Medicare Limited Dataset for 2010 to 2012 for total and partial nephrectomy for benign and malignant neoplasms to create prediction models for the adverse outcomes (AOs) of inpatient deaths, prolonged length-of-stay outliers, 90-day postdischarge deaths without readmission, and 90-day relevant readmissions. From the 4 prediction models, total predicted adverse outcomes were determined for each hospital in the dataset that met a minimum of 25 evaluable cases for the study period. Standard deviations (SDs) for each hospital were used to identify specific z-scores. Risk-adjusted adverse outcomes rates were computed to permit benchmarking each hospital's performance against the national standard. Differences between best and suboptimal performing hospitals defined the potential margin of preventable adverse outcomes for this operation.A total of 449 hospitals with 23,477 patients were evaluated. Overall AO rate was 20.8%; 17 hospitals had risk-adjusted AO rates that were 2 SDs poorer than predicted and 8 were 2 SDs better. The top performing decile of hospitals had a risk-adjusted AO rate of 10.2% while the lowest performing decile had 32.1%. With a minimum of 25 cases for each study hospital, no statistically valid improvement in outcomes was seen with increased case volume.Inpatient and 90-day postdischarge risk-adjusted adverse outcomes demonstrated marked variability among study hospitals and illustrate the opportunities for care improvement. This analytic design is applicable for comparing provider

  11. Meaningful QQ adjustment of TRMM/GPM daily rainfall estimates.

    NASA Astrophysics Data System (ADS)

    Pegram, Geoff; Bardossy, Andras; Sinclair, Scott

    2016-04-01

    In many parts of the world, particularly in Africa, the daily raingauge networks are sparse. It is therefore sensible to use remote sensing estimates of precipitation to fill the gaps, but readily available products like TRMM and it successor GPM are frequently found to be biased. This presentation describes a method of bias adjustment of TRMM using quantile-quantile (QQ) transforms of the probability distributions of TRMM daily rainfall accumulations over its grid of 0.25 degree pixels/blocks. There are 4 main steps in the procedure. The first is to collect the daily gauge readings in those TRMM pixels containing gauges to obtain useful estimates of spatial rainfall for ground referencing. These estimates need to be adjusted from gauge to areal estimates taking the number of gauges in each pixel into account. We found that the distributions of the areal rainfall estimates are influenced by the number of gauges in each block, so we devised a means of transforming point to areal rainfall meaningfully. The second step is to determine the parameters of the probability distributions of the gauge-based block areal rainfall; we found that the Weibull distribution with 2 parameters is a suitable and useful choice. The pairs of Weibull parameters of rainfall on many blocks are correlated. To enable their interpolation, as an intermediate step, they have to be decorrelated using canonical decomposition. These transformed parameter pairs are then separately interpolated to empty blocks over the region of choice. They are then back-transformed at each TRMM pixel to Weibull parameters to provide gauge referenced daily rainfall distributions. The third step is to determine the Weibull distributions of the TRMM daily rainfall estimates in each block, based on their brief 11-year history. The fourth and last step is to QQ transform the individual daily TRMM rainfall estimates via the interpolated gauge-block rainfall distributions. This procedure achieves the desired corrected

  12. Risk adjusting community rated health plan premiums: a survey of risk assessment literature and policy applications.

    PubMed

    Giacomini, M; Luft, H S; Robinson, J C

    1995-01-01

    This paper surveys recent health care reform debates and empirical evidence regarding the potential role for risk adjusters in addressing the problem of competitive risk segmentation under capitated financing. We discuss features of health plan markets affecting risk selection, methodological considerations in measuring it, and alternative approaches to financial correction for risk differentials. The appropriate approach to assessing risk differences between health plans depends upon the nature of market risk selection allowed under a given reform scenario. Because per capita costs depend on a health plan's population risk, efficiency, and quality of service, risk adjustment will most strongly promote efficiency in environments with commensurately strong incentives for quality care. PMID:7639879

  13. Personality, emotional adjustment, and cardiovascular risk: marriage as a mechanism.

    PubMed

    Smith, Timothy W; Baron, Carolynne E; Grove, Jeremy L

    2014-12-01

    A variety of aspects of personality and emotional adjustment predict the development and course of coronary heart disease (CHD), as do indications of marital quality (e.g., satisfaction, conflict, strain, disruption). Importantly, the personality traits and aspects of emotional adjustment that predict CHD are also related to marital quality. In such instances of correlated risk factors, traditional epidemiological and clinical research typically either ignores the potentially overlapping effects or examines independent associations through statistical controls, approaches that can misrepresent the key components and mechanisms of psychosocial effects on CHD. The interpersonal perspective in personality and clinical psychology provides an alternative and integrative approach, through its structural and process models of interpersonal behavior. We present this perspective on psychosocial risk and review research on its application to the integration of personality, emotional adjustment, and marital processes as closely interrelated influences on health and disease. PMID:24118013

  14. The risk-adjusted cost evaluation of electric resource alternatives

    SciTech Connect

    Duane, T.P.

    1989-01-01

    Partial deregulation of the electric utility industry has occurred under the Public Utilities Regulatory Policies Act of 1978 (PURPA), which shifts the balance of both costs and risks between rate payers and electric utilities. Cost comparisons of potential electric resource Alternatives currently rely on techniques which do not explicitly incorporate risk consideration. This reflects the traditional role of regulation for rate stabilization. Risk-averse residential rate payers with low demand elasticities may highly value price risk reduction, but risk is not explicitly considered by present planning systems. There is a need to quantify the value of such price risk reduction. This research attempts to develop a Risk-Adjusted Cost Evaluation (RACE) methodology for direct comparisons of competing alternatives by a single risk-adjusted cost criterion. Methodologies have previously been developed for risk pricing in financial and commodities markets, and those techniques are evaluated for extension to the electricity market problem. Each has important deficiencies in the institutional context of electricity markets under PURPA; each also offers important insights for development of a simplified RACE methodology synthesizing those models. The methodology is applied to a large California utility, and major implementation problems are identified. The approach requires strict limiting conditions, and price risk reduction does not have a significant value to residential customers of PG and E. This may be less true for less well-diversified utilities, and several conditions are identified where more detailed assessment of risk implications is warranted. Future risk analyses research should instead focus on large, asymmetric risks. Suggestions are made for assessment of such risks through an insurance market metaphor and decision analysis methods.

  15. How to estimate your tolerance for risk

    SciTech Connect

    Mackay, J.A.

    1996-12-31

    Risk tolerance is used to calculate the Risk Adjusted Value (RAV) of a proposed investment. The RAV incorporates both the expected value and risk attitude for a particular investment, taking into consideration your concern for catastrophic financial loss, as well as chance of success, cost and value if successful. Uncertainty can be incorporated into all of the above variables. Often a project is more valuable to a corporation if a partial working interest is taken rather than the entire working interest. The RAV can be used to calculate the optimum working interest and the value of that diversification. To estimate the Apparent Risk Tolerance (ART) of an individual, division or corporation several methods can be employed: (1) ART can be calculated from the working interest selected in prior investment decisions. (2) ART can be estimated from a selection of working interests by the decision maker in a proposed portfolio of projects. (3) ART can be approximated from data released to the Security and Exchange Commission (SEC) in the annual 10K supplements (for both your company and possible partners). (4) ART can be assigned based on corporate size, budget, or activity. Examples are provided for the various methods to identify risk tolerance and apply it in making optimum working interest calculations for individual projects and portfolios.

  16. Risk selection, risk adjustment and choice: concepts and lessons from the Americas.

    PubMed

    Ellis, Randall P; Fernandez, Juan Gabriel

    2013-11-01

    Interest has grown worldwide in risk adjustment and risk sharing due to their potential to contain costs, improve fairness, and reduce selection problems in health care markets. Significant steps have been made in the empirical development of risk adjustment models, and in the theoretical foundations of risk adjustment and risk sharing. This literature has often modeled the effects of risk adjustment without highlighting the institutional setting, regulations, and diverse selection problems that risk adjustment is intended to fix. Perhaps because of this, the existing literature and their recommendations for optimal risk adjustment or optimal payment systems are sometimes confusing. In this paper, we present a unified way of thinking about the organizational structure of health care systems, which enables us to focus on two key dimensions of markets that have received less attention: what choices are available that may lead to selection problems, and what financial or regulatory tools other than risk adjustment are used to influence these choices. We specifically examine the health care systems, choices, and problems in four countries: the US, Canada, Chile, and Colombia, and examine the relationship between selection-related efficiency and fairness problems and the choices that are allowed in each country, and discuss recent regulatory reforms that affect choices and selection problems. In this sample, countries and insurance programs with more choices have more selection problems. PMID:24284351

  17. Risk Selection, Risk Adjustment and Choice: Concepts and Lessons from the Americas

    PubMed Central

    Ellis, Randall P.; Fernandez, Juan Gabriel

    2013-01-01

    Interest has grown worldwide in risk adjustment and risk sharing due to their potential to contain costs, improve fairness, and reduce selection problems in health care markets. Significant steps have been made in the empirical development of risk adjustment models, and in the theoretical foundations of risk adjustment and risk sharing. This literature has often modeled the effects of risk adjustment without highlighting the institutional setting, regulations, and diverse selection problems that risk adjustment is intended to fix. Perhaps because of this, the existing literature and their recommendations for optimal risk adjustment or optimal payment systems are sometimes confusing. In this paper, we present a unified way of thinking about the organizational structure of health care systems, which enables us to focus on two key dimensions of markets that have received less attention: what choices are available that may lead to selection problems, and what financial or regulatory tools other than risk adjustment are used to influence these choices. We specifically examine the health care systems, choices, and problems in four countries: the US, Canada, Chile, and Colombia, and examine the relationship between selection-related efficiency and fairness problems and the choices that are allowed in each country, and discuss recent regulatory reforms that affect choices and selection problems. In this sample, countries and insurance programs with more choices have more selection problems. PMID:24284351

  18. Latino risk-adjusted mortality in the men screened for the Multiple Risk Factor Intervention Trial.

    PubMed

    Thomas, Avis J; Eberly, Lynn E; Neaton, James D; Smith, George Davey

    2005-09-15

    Latinos are now the largest minority in the United States, but their distinctive health needs and mortality patterns remain poorly understood. Proportional hazards regressions were used to compare Latino versus White risk- and income-adjusted mortality over 25 years' follow-up from 5,846 Latino and 300,647 White men screened for the Multiple Risk Factor Intervention Trial. Men were aged 35-57 years and residing in 14 states when screened in 1973-1975. Data on coronary heart disease risk factors, self-reported race/ethnicity, and home addresses were obtained at baseline; income was estimated by linking addresses to census data. Mortality follow-up through 1999 was obtained using the National Death Index. The fully adjusted Latino/White hazard ratio for all-cause mortality was 0.82 (95% confidence interval (CI): 0.77, 0.87), based on 1,085 Latino and 73,807 White deaths; this pattern prevailed over time and across states (thus, likely across Latino subgroups). Hazard ratios were significantly greater than one for stroke (hazard ratio = 1.30, 95% CI: 1.01, 1.68), liver cancer (hazard ratio = 2.02, 95% CI: 1.21, 3.37), and infection (hazard ratio = 1.69, 95% CI: 1.24, 2.32). A substudy found only minor racial/ethnic differences in the quality of Social Security numbers, birth dates, soundex-adjusted names, and National Death Index searches. Results were not likely an artifact of return migration or incomplete mortality data. PMID:16076831

  19. 45 CFR 153.360 - Application of risk adjustment to the small group market.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... RELATING TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.360...

  20. 45 CFR 153.360 - Application of risk adjustment to the small group market.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... RELATING TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT State Standards Related to the Risk Adjustment Program § 153.360...

  1. Bias-adjusted satellite-based rainfall estimates for predicting floods: Narayani Basin

    USGS Publications Warehouse

    Shrestha, M.S.; Artan, G.A.; Bajracharya, S.R.; Gautam, D.K.; Tokar, S.A.

    2011-01-01

    In Nepal, as the spatial distribution of rain gauges is not sufficient to provide detailed perspective on the highly varied spatial nature of rainfall, satellite-based rainfall estimates provides the opportunity for timely estimation. This paper presents the flood prediction of Narayani Basin at the Devghat hydrometric station (32000km2) using bias-adjusted satellite rainfall estimates and the Geospatial Stream Flow Model (GeoSFM), a spatially distributed, physically based hydrologic model. The GeoSFM with gridded gauge observed rainfall inputs using kriging interpolation from 2003 was used for calibration and 2004 for validation to simulate stream flow with both having a Nash Sutcliff Efficiency of above 0.7. With the National Oceanic and Atmospheric Administration Climate Prediction Centre's rainfall estimates (CPC-RFE2.0), using the same calibrated parameters, for 2003 the model performance deteriorated but improved after recalibration with CPC-RFE2.0 indicating the need to recalibrate the model with satellite-based rainfall estimates. Adjusting the CPC-RFE2.0 by a seasonal, monthly and 7-day moving average ratio, improvement in model performance was achieved. Furthermore, a new gauge-satellite merged rainfall estimates obtained from ingestion of local rain gauge data resulted in significant improvement in flood predictability. The results indicate the applicability of satellite-based rainfall estimates in flood prediction with appropriate bias correction. ?? 2011 The Authors. Journal of Flood Risk Management ?? 2011 The Chartered Institution of Water and Environmental Management.

  2. The structure of risk adjustment for private plans in Medicare.

    PubMed

    Newhouse, Joseph P; Huang, Jie; Brand, Richard J; Fung, Vicki; Hsu, John T

    2011-06-01

    Medicare bases its risk adjustment method for Medicare Advantage plan payment on the relative costs of treating various diagnoses in traditional Medicare. However, there are many reasons to doubt that the relative cost of treating different diagnoses is similar between Medicare Advantage plans and traditional Medicare, including the varying applicability of care management methods to different diagnoses and the varying degrees of market power among suppliers of services to plans. We use internal cost data from a large health plan to compare its cost of treating various diagnoses with Medicare's reimbursement. We find substantial variability across diagnoses, implying that the current risk adjustment system creates incentives for Medicare Advantage plans to favor beneficiaries with certain diagnoses, but find no consistent relationship between the costliness of the diagnosis and the difference between reimbursement and cost. PMID:21756017

  3. Population-Attributable Risk Estimates for Risk Factors Associated with Campylobacter Infection, Australia

    PubMed Central

    Schluter, Philip J.; Wilson, Andrew J.; Kirk, Martyn D.; Hall, Gillian; Unicomb, Leanne

    2008-01-01

    In 2001–2002, a multicenter, prospective case-control study involving 1,714 participants >5 years of age was conducted in Australia to identify risk factors for Campylobacter infection. Adjusted population-attributable risks (PARs) were derived for each independent risk factor contained within the final multivariable logistic regression model. Estimated PARs were combined with adjusted (for the >5 years of age eligibility criterion) notifiable disease surveillance data to estimate annual Australian Campylobacter case numbers attributable to each risk factor. Simulated distributions of “credible values” were then generated to model the uncertainty associated with each case number estimate. Among foodborne risk factors, an estimated 50,500 (95% credible interval 10,000–105,500) cases of Campylobacter infection in persons >5 years of age could be directly attributed each year to consumption of chicken in Australia. Our statistical technique could be applied more widely to other communicable diseases that are subject to routine surveillance. PMID:18507899

  4. Estimation of adjusted rate differences using additive negative binomial regression.

    PubMed

    Donoghoe, Mark W; Marschner, Ian C

    2016-08-15

    Rate differences are an important effect measure in biostatistics and provide an alternative perspective to rate ratios. When the data are event counts observed during an exposure period, adjusted rate differences may be estimated using an identity-link Poisson generalised linear model, also known as additive Poisson regression. A problem with this approach is that the assumption of equality of mean and variance rarely holds in real data, which often show overdispersion. An additive negative binomial model is the natural alternative to account for this; however, standard model-fitting methods are often unable to cope with the constrained parameter space arising from the non-negativity restrictions of the additive model. In this paper, we propose a novel solution to this problem using a variant of the expectation-conditional maximisation-either algorithm. Our method provides a reliable way to fit an additive negative binomial regression model and also permits flexible generalisations using semi-parametric regression functions. We illustrate the method using a placebo-controlled clinical trial of fenofibrate treatment in patients with type II diabetes, where the outcome is the number of laser therapy courses administered to treat diabetic retinopathy. An R package is available that implements the proposed method. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27073156

  5. Effect of Wound Classification on Risk-Adjustment in American College of Surgeons NSQIP

    PubMed Central

    Ju, Mila H.; Cohen, Mark E.; Bilimoria, Karl Y.; Latus, Melissa S.; Scholl, Lisa M.; Schwab, Bradley J.; Byrd, Claudia M.; Ko, Clifford Y.; Dellinger, E. Patchen; Hall, Bruce L.

    2014-01-01

    Background Surgical wound classification has been used in risk-adjustment models. However, it can be subjective and potentially improperly bias hospital quality comparisons. The objective is to examine the effect of wound classification on hospital performance risk-adjustment models. Study Design Retrospective review of the 2011 ACS NSQIP database was conducted for wound classification categories: clean, clean/contaminated, contaminated, and dirty/infected. To assess the influence of wound classification on risk-adjustment, two models were developed for each outcome: one including and one excluding wound classification. For each model, hospital postoperative complications were estimated using hierarchical multivariable regression methods. Absolute changes in hospital rank, correlations of odds-ratios, and outlier status agreement between models were examined. Results Of the 442,149 cases performed in 315 hospitals: 53.6% were classified as clean; 34.2% clean/contaminated; 6.7% contaminated; and 5.5% dirty/infected. The surgical site infection (SSI) rate was highest in dirty/infected (8.5%) and lowest in clean (1.8%) cases. For overall SSI, the absolute change in risk-adjusted hospital performance rank between models including vs. excluding wound classification was minimal (mean 4.5 out of 315 positions). The correlations between odds ratios of the two performance models were nearly perfect (R=0.9976, P<0.0001), and outlier status agreement was excellent (Kappa=0.9508, P<0.0001). Similar findings were observed in models of subgroups of SSI and other postoperative outcomes. Conclusions In circumstances where alternate information is available for risk-adjustment, there appear to be minimal differences in performance models that include vs. exclude wound classification. Therefore, ACS NSQIP is critically evaluating the continued use of wound classification in hospital performance risk-adjustment models. PMID:25053222

  6. Risk Adjustment and Primary Health Care in Chile

    PubMed Central

    Vargas, Veronica; Wasem, Juergen

    2006-01-01

    Aim To offer a capitation formula with greater capacity for guiding resource spending on population with poorer health and lower socioeconomic status in the context of financing and equity in primary health care. Methods We collected two years of data on a sample of 10 000 individuals from a region in Chile, Valdivia and Temuco and evaluated three models to estimate utilization and expenditures per capita. The first model included age and sex; the second one included age, sex, and the presence of two key diagnoses; and the third model included age, sex, and the presence of seven key diagnoses. Regression results were evaluated by R2 and predictive ratios to select the best specifications. Results Per-capita expenditures by age and sex confirmed international trends, where children under five, women, and the elderly were the main users of primary health care services. Women sought health advice twice as much as men. Clear differences by socioeconomic status were observed for the indigent population aged ≥65 years who under-utilized primary health care services. From the three models, major improvement in the predictive power occurred from the demographic (adjusted R2, 9%) to the demographic plus two diagnoses model (adjusted R2, 27%). Improvements were modest when five other diagnoses were added (adjusted R2, 28%). Conclusion The current formula that uses municipality’s financial power and geographic location of health centers to adjust capitation payments provides little incentive to appropriate care for the indigent and people with chronic conditions. A capitation payment that adjusts for age, sex, and the presence of diabetes and hypertension will better guide resource allocation to those with poorer health and lower socioeconomic status. PMID:16758525

  7. 78 FR 32255 - HHS-Operated Risk Adjustment Data Validation Stakeholder Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ...This notice announces a public meeting on the Affordable Care Act HHS-operated risk adjustment data validation process. The purpose of this public meeting is to provide opportunity to discuss the HHS risk adjustment data validation process that will be conducted when HHS operates the risk adjustment program on behalf of a state under the Affordable Care Act. The meeting will provide......

  8. Level of education and multiple sclerosis risk after adjustment for known risk factors: The EnvIMS study

    PubMed Central

    Bjørnevik, Kjetil; Riise, Trond; Cortese, Marianna; Holmøy, Trygve; Kampman, Margitta T; Magalhaes, Sandra; Myhr, Kjell-Morten; Wolfson, Christina; Pugliatti, Maura

    2016-01-01

    Background: Several recent studies have found a higher risk of multiple sclerosis (MS) among people with a low level of education. This has been suggested to reflect an effect of smoking and lower vitamin D status in the social class associated with lower levels of education. Objective: The objective of this paper is to investigate the association between level of education and MS risk adjusting for the known risk factors smoking, infectious mononucleosis, indicators of vitamin D levels and body size. Methods: Within the case-control study on Environmental Factors In MS (EnvIMS), 953 MS patients and 1717 healthy controls from Norway reported educational level and history of exposure to putative environmental risk factors. Results: Higher level of education were associated with decreased MS risk (p trend = 0.001) with an OR of 0.53 (95% CI 0.41–0.68) when comparing those with the highest and lowest level of education. This association was only moderately reduced after adjusting for known risk factors (OR 0.61, 95% CI 0.44–0.83). The estimates remained similar when cases with disease onset before age 28 were excluded. Conclusion: These findings suggest that factors related to lower socioeconomic status other than established risk factors are associated with MS risk. PMID:26014605

  9. Adjustment of Sensor Locations During Thermal Property Parameter Estimation

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.; Marschall, Jochen; Rasky, Daniel J. (Technical Monitor)

    1996-01-01

    The temperature dependent thermal properties of a material may be evaluated from transient temperature histories using nonlinear parameter estimation techniques. The usual approach is to minimize the sum of the squared errors between measured and calculated temperatures at specific locations in the body. Temperature measurements are usually made with thermocouples and it is customary to take thermocouple locations as known and fixed during parameter estimation computations. In fact, thermocouple locations are never known exactly. Location errors on the order of the thermocouple wire diameter are intrinsic to most common instrumentation procedures (e.g., inserting a thermocouple into a drilled hole) and additional errors can be expected for delicate materials, difficult installations, large thermocouple beads, etc.. Thermocouple location errors are especially significant when estimating thermal properties of low diffusively materials which can sustain large temperature gradients during testing. In the present work, a parameter estimation formulation is presented which allows for the direct inclusion of thermocouple positions into the primary parameter estimation procedure. It is straightforward to set bounds on thermocouple locations which exclude non-physical locations and are consistent with installation tolerances. Furthermore, bounds may be tightened to an extent consistent with any independent verification of thermocouple location, such as x-raying, and so the procedure is entirely consonant with experimental information. A mathematical outline of the procedure is given and its implementation is illustrated through numerical examples characteristic of light-weight, high-temperature ceramic insulation during transient heating. The efficacy and the errors associated with the procedure are discussed.

  10. 45 CFR 153.630 - Data validation requirements when HHS operates risk adjustment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false Data validation requirements when HHS operates risk adjustment. 153.630 Section 153.630 Public Welfare Department of Health and Human Services REQUIREMENTS RELATING TO HEALTH CARE ACCESS STANDARDS RELATED TO REINSURANCE, RISK CORRIDORS, AND RISK ADJUSTMENT UNDER THE AFFORDABLE CARE ACT...

  11. Estimation of Data Uncertainty Adjustment Parameters for Multivariate Earth Rotation Series

    NASA Technical Reports Server (NTRS)

    Sung, Li-yu; Steppe, J. Alan

    1994-01-01

    We have developed a maximum likelihood method to estimate a set of data uncertainty adjustment parameters, iccluding scaling factors and additive variances and covariances, for multivariate Earth rotation series.

  12. Case‐mix adjustment in non‐randomised observational evaluations: the constant risk fallacy

    PubMed Central

    Nicholl, Jon

    2007-01-01

    Observational studies comparing groups or populations to evaluate services or interventions usually require case‐mix adjustment to account for imbalances between the groups being compared. Simulation studies have, however, shown that case‐mix adjustment can make any bias worse. One reason this can happen is if the risk factors used in the adjustment are related to the risk in different ways in the groups or populations being compared, and ignoring this commits the “constant risk fallacy”. Case‐mix adjustment is particularly prone to this problem when the adjustment uses factors that are proxies for the real risk factors. Interactions between risk factors and groups should always be examined before case‐mix adjustment in observational studies. PMID:17933961

  13. Dynamic cost risk estimation and budget misspecification

    NASA Technical Reports Server (NTRS)

    Ebbeler, D. H.; Fox, G.; Habib-Agahi, H.

    2003-01-01

    Cost risk for new technology development is estimated by explicit stochastic processes. Monte Carlo simulation is used to propagate technology development activity budget changes during the technology development cycle.

  14. Uranium mill tailings and risk estimation

    SciTech Connect

    Marks, S.

    1984-04-01

    Work done in estimating projected health effects for persons exposed to mill tailings at vicinity properties is described. The effect of the reassessment of exposures at Hiroshima and Nagasaki on the risk estimates for gamma radiation is discussed. A presentation of current results in the epidemiological study of Hanford workers is included. 2 references. (ACR)

  15. Adjustment of Children Born to Teenage Mothers: The Contribution of Risk and Protective Factors.

    ERIC Educational Resources Information Center

    Dubow, Eric F.; Luster, Tom

    1990-01-01

    Examined contribution of risk and protective factors in adjustment of 721 children, age 8-15, born to teenage mothers. Results showed that exposure to increasing number of risk factors (poverty, urban residence, mother's self-esteem) was associated with greater vulnerability to adjustment problems, while protective factors (intelligence,…

  16. Cumulative Family Risk Predicts Increases in Adjustment Difficulties across Early Adolescence

    ERIC Educational Resources Information Center

    Buehler, Cheryl; Gerard, Jean M.

    2013-01-01

    Family is an important socialization context for youth as they move through early adolescence. A significant feature of this complex socialization context is the accumulation of potential family risk factors that may compromise youth adjustment. This study examined cumulative family risk and adolescents' adjustment difficulties in 416 two-parent…

  17. Submarine tower escape decompression sickness risk estimation.

    PubMed

    Loveman, G A M; Seddon, E M; Thacker, J C; Stansfield, M R; Jurd, K M

    2014-01-01

    Actions to enhance survival in a distressed submarine (DISSUB) scenario may be guided in part by knowledge of the likely risk of decompression sickness (DCS) should the crew attempt tower escape. A mathematical model for DCS risk estimation has been calibrated against DCS outcome data from 3,738 exposures of either men or goats to raised pressure. Body mass was used to scale DCS risk. The calibration data included more than 1,000 actual or simulated submarine escape exposures and no exposures with substantial staged decompression. Cases of pulmonary barotrauma were removed from the calibration data. The calibrated model was used to estimate the likelihood of DCS occurrence following submarine escape from the United Kingdom Royal Navy tower escape system. Where internal DISSUB pressure remains at - 0.1 MPa, escape from DISSUB depths < 200 meters is estimated to have DCS risk < 6%. Saturation at raised DISSUB pressure markedly increases risk, with > 60% DCS risk predicted for a 200-meter escape from saturation at 0.21 MPa. Using the calibrated model to predict DCS for direct ascent from saturation gives similar risk estimates to other published models. PMID:25109085

  18. Cause-specific premature death from ambient PM2.5 exposure in India: Estimate adjusted for baseline mortality.

    PubMed

    Chowdhury, Sourangsu; Dey, Sagnik

    2016-05-01

    In India, more than a billion population is at risk of exposure to ambient fine particulate matter (PM2.5) concentration exceeding World Health Organization air quality guideline, posing a serious threat to health. Cause-specific premature death from ambient PM2.5 exposure is poorly known for India. Here we develop a non-linear power law (NLP) function to estimate the relative risk associated with ambient PM2.5 exposure using satellite-based PM2.5 concentration (2001-2010) that is bias-corrected against coincident direct measurements. We show that estimate of annual premature death in India is lower by 14.7% (19.2%) using NLP (integrated exposure risk function, IER) for assumption of uniform baseline mortality across India (as considered in the global burden of disease study) relative to the estimate obtained by adjusting for state-specific baseline mortality using GDP as a proxy. 486,100 (811,000) annual premature death in India is estimated using NLP (IER) risk functions after baseline mortality adjustment. 54.5% of premature death estimated using NLP risk function is attributed to chronic obstructive pulmonary disease (COPD), 24.0% to ischemic heart disease (IHD), 18.5% to stroke and the remaining 3.0% to lung cancer (LC). 44,900 (5900-173,300) less premature death is expected annually, if India achieves its present annual air quality target of 40μgm(-3). Our results identify the worst affected districts in terms of ambient PM2.5 exposure and resulting annual premature death and call for initiation of long-term measures through a systematic framework of pollution and health data archive. PMID:27063285

  19. Uncertainty-based Estimation of the Secure Range for ISO New England Dynamic Interchange Adjustment

    SciTech Connect

    Etingov, Pavel V.; Makarov, Yuri V.; Wu, Di; Hou, Zhangshuan; Sun, Yannan; Maslennikov, S.; Luo, Xiaochuan; Zheng, T.; George, S.; Knowland, T.; Litvinov, E.; Weaver, S.; Sanchez, E.

    2014-04-14

    The paper proposes an approach to estimate the secure range for dynamic interchange adjustment, which assists system operators in scheduling the interchange with neighboring control areas. Uncertainties associated with various sources are incorporated. The proposed method is implemented in the dynamic interchange adjustment (DINA) tool developed by Pacific Northwest National Laboratory (PNNL) for ISO New England. Simulation results are used to validate the effectiveness of the proposed method.

  20. Log Pearson type 3 quantile estimators with regional skew information and low outlier adjustments

    USGS Publications Warehouse

    Griffis, V.W.; Stedinger, J.R.; Cohn, T.A.

    2004-01-01

    [1] The recently developed expected moments algorithm (EMA) [Cohn et al., 1997] does as well as maximum likelihood estimations at estimating log-Pearson type 3 (LP3) flood quantiles using systematic and historical flood information. Needed extensions include use of a regional skewness estimator and its precision to be consistent with Bulletin 17B. Another issue addressed by Bulletin 17B is the treatment of low outliers. A Monte Carlo study compares the performance of Bulletin 17B using the entire sample with and without regional skew with estimators that use regional skew and censor low outliers, including an extended EMA estimator, the conditional probability adjustment (CPA) from Bulletin 17B, and an estimator that uses probability plot regression (PPR) to compute substitute values for low outliers. Estimators that neglect regional skew information do much worse than estimators that use an informative regional skewness estimator. For LP3 data the low outlier rejection procedure generally results in no loss of overall accuracy, and the differences between the MSEs of the estimators that used an informative regional skew are generally modest in the skewness range of real interest. Samples contaminated to model actual flood data demonstrate that estimators which give special treatment to low outliers significantly outperform estimators that make no such adjustment.

  1. Odds per adjusted standard deviation: comparing strengths of associations for risk factors measured on different scales and across diseases and populations.

    PubMed

    Hopper, John L

    2015-11-15

    How can the "strengths" of risk factors, in the sense of how well they discriminate cases from controls, be compared when they are measured on different scales such as continuous, binary, and integer? Given that risk estimates take into account other fitted and design-related factors-and that is how risk gradients are interpreted-so should the presentation of risk gradients. Therefore, for each risk factor X0, I propose using appropriate regression techniques to derive from appropriate population data the best fitting relationship between the mean of X0 and all the other covariates fitted in the model or adjusted for by design (X1, X2, … , Xn). The odds per adjusted standard deviation (OPERA) presents the risk association for X0 in terms of the change in risk per s = standard deviation of X0 adjusted for X1, X2, … , Xn, rather than the unadjusted standard deviation of X0 itself. If the increased risk is relative risk (RR)-fold over A adjusted standard deviations, then OPERA = exp[ln(RR)/A] = RR(s). This unifying approach is illustrated by considering breast cancer and published risk estimates. OPERA estimates are by definition independent and can be used to compare the predictive strengths of risk factors across diseases and populations. PMID:26520360

  2. Spatial ascariasis risk estimation using socioeconomic variables.

    PubMed

    Valencia, Luis Iván Ortiz; Fortes, Bruno de Paula Menezes Drumond; Medronho, Roberto de Andrade

    2005-12-01

    Frequently, disease incidence is mapped as area data, for example, census tracts, districts or states. Spatial disease incidence can be highly heterogeneous inside these areas. Ascariasis is a highly prevalent disease, which is associated with poor sanitation and hygiene. Geostatistics was applied to model spatial distribution of Ascariasis risk and socioeconomic risk events in a poor community in Rio de Janeiro, Brazil. Data were gathered from a coproparasitologic and a domiciliary survey in 1550 children aged 1-9. Ascariasis risk and socioeconomic risk events were spatially estimated using Indicator Kriging. Cokriging models with a Linear Model of Coregionalization incorporating one socioeconomic variable were implemented. If a housewife attended school for less than four years, the non-use of a home water filter, a household density greater than one, and a household income lower than one Brazilian minimum wage increased the risk of Ascariasis. Cokriging improved spatial estimation of Ascariasis risk areas when compared to Indicator Kriging and detected more Ascariasis very-high risk areas than the GIS Overlay method. PMID:16506435

  3. Why people do what they do to protect against earthquake risk: perceptions of hazard adjustment attributes.

    PubMed

    Lindell, Michael K; Arlikatti, Sudha; Prater, Carla S

    2009-08-01

    This study examined respondents' self-reported adoption of 16 hazard adjustments (preimpact actions to reduce danger to persons and property), their perceptions of those adjustments' attributes, and the correlations of those perceived attributes with respondents' demographic characteristics. The sample comprised 561 randomly selected residents from three cities in Southern California prone to high seismic risk and three cities from Western Washington prone to moderate seismic risks. The results show that the hazard adjustment perceptions were defined by hazard-related attributes and resource-related attributes. More significantly, the respondents had a significant degree of consensus in their ratings of those attributes and used them to differentiate among the hazard adjustments, as indicated by statistically significant differences among the hazard adjustment profiles. Finally, there were many significant correlations between respondents' demographic characteristics and the perceived characteristics of hazard adjustments, but there were few consistent patterns among these correlations. PMID:19508448

  4. Bias adjustment of satellite-based precipitation estimation using gauge observations: A case study in Chile

    NASA Astrophysics Data System (ADS)

    Yang, Zhongwen; Hsu, Kuolin; Sorooshian, Soroosh; Xu, Xinyi; Braithwaite, Dan; Verbist, Koen M. J.

    2016-04-01

    Satellite-based precipitation estimates (SPEs) are promising alternative precipitation data for climatic and hydrological applications, especially for regions where ground-based observations are limited. However, existing satellite-based rainfall estimations are subject to systematic biases. This study aims to adjust the biases in the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS) rainfall data over Chile, using gauge observations as reference. A novel bias adjustment framework, termed QM-GW, is proposed based on the nonparametric quantile mapping approach and a Gaussian weighting interpolation scheme. The PERSIANN-CCS precipitation estimates (daily, 0.04°×0.04°) over Chile are adjusted for the period of 2009-2014. The historical data (satellite and gauge) for 2009-2013 are used to calibrate the methodology; nonparametric cumulative distribution functions of satellite and gauge observations are estimated at every 1°×1° box region. One year (2014) of gauge data was used for validation. The results show that the biases of the PERSIANN-CCS precipitation data are effectively reduced. The spatial patterns of adjusted satellite rainfall show high consistency to the gauge observations, with reduced root-mean-square errors and mean biases. The systematic biases of the PERSIANN-CCS precipitation time series, at both monthly and daily scales, are removed. The extended validation also verifies that the proposed approach can be applied to adjust SPEs into the future, without further need for ground-based measurements. This study serves as a valuable reference for the bias adjustment of existing SPEs using gauge observations worldwide.

  5. 48 CFR 215.404-71-3 - Contract type risk and working capital adjustment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... assessment shall include any reduced contractor risk on both the contract before definitization and the... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Contract type risk and... CONTRACTING BY NEGOTIATION Contract Pricing 215.404-71-3 Contract type risk and working capital adjustment....

  6. IMPROVED RISK ESTIMATES FOR CARBON TETRACHLORIDE

    EPA Science Inventory

    Carbon tetrachloride (CCl4) has been used extensively within the Department of Energy (DOE) nuclear weapons facilities. Costs associated with cleanup of CCl4 at DOE facilities are driven by current cancer risk estimates which assume CCl4 is a genotoxic carcinogen. However, a grow...

  7. Secondary prevention and estimation of fracture risk.

    PubMed

    Mitchell, Paul James; Chem, C

    2013-12-01

    The key questions addressed in this chapter are: • How can individual risk of fracture be best estimated? • What is the best system to prevent a further fracture? • How to implement systems for preventing further fractures? Absolute fracture risk calculators (FRCs) provide a means to estimate an individual's future fracture risk. FRCs are widely available and provide clinicians and patients a platform to discuss the need for intervention to prevent fragility fractures. Despite availability of effective osteoporosis medicines for almost two decades, most patients presenting with new fragility fractures do not receive secondary preventive care. The Fracture Liaison Service (FLS) model has been shown in a number of countries to eliminate the care gap in a clinically and cost-effective manner. Leading international and national organisations have developed comprehensive resources and/or national strategy documents to provide guidance on implementation of FLS in local, regional and national health-care systems. PMID:24836336

  8. Estimating Terrorist Risk with Possibility Theory

    SciTech Connect

    J.L. Darby

    2004-11-30

    This report summarizes techniques that use possibility theory to estimate the risk of terrorist acts. These techniques were developed under the sponsorship of the Department of Homeland Security (DHS) as part of the National Infrastructure Simulation Analysis Center (NISAC) project. The techniques have been used to estimate the risk of various terrorist scenarios to support NISAC analyses during 2004. The techniques are based on the Logic Evolved Decision (LED) methodology developed over the past few years by Terry Bott and Steve Eisenhawer at LANL. [LED] The LED methodology involves the use of fuzzy sets, possibility theory, and approximate reasoning. LED captures the uncertainty due to vagueness and imprecision that is inherent in the fidelity of the information available for terrorist acts; probability theory cannot capture these uncertainties. This report does not address the philosophy supporting the development of nonprobabilistic approaches, and it does not discuss possibility theory in detail. The references provide a detailed discussion of these subjects. [Shafer] [Klir and Yuan] [Dubois and Prade] Suffice to say that these approaches were developed to address types of uncertainty that cannot be addressed by a probability measure. An earlier report discussed in detail the problems with using a probability measure to evaluate terrorist risk. [Darby Methodology]. Two related techniques are discussed in this report: (1) a numerical technique, and (2) a linguistic technique. The numerical technique uses traditional possibility theory applied to crisp sets, while the linguistic technique applies possibility theory to fuzzy sets. Both of these techniques as applied to terrorist risk for NISAC applications are implemented in software called PossibleRisk. The techniques implemented in PossibleRisk were developed specifically for use in estimating terrorist risk for the NISAC program. The LEDTools code can be used to perform the same linguistic evaluation as

  9. Estimating the Burden of Cancers Attributable to Smoking Using Disability Adjusted Life Years in Indonesia.

    PubMed

    Kristina, Susi Ari; Endarti, Dwi; Sendjaya, Natalia; Pramestuty, Octy

    2016-01-01

    Tobacco use is a well-established risk factor for many types of cancers. Recent data on selected cancer incidence and mortality related to smoking in the Indonesian population are provided in this study. Morbidity and mortality data were derived from GLOBOCAN 2012 and the population attributable fraction (PAF) was estimated using the standard methodology developed by the World Health Organization. Using these data, we calculated disability adjusted life year (DALY) values for smoking-related cancer. The DALY was estimated by summation of the years lived with disability (YLD) and years life lost due to premature death (YLL). The cancer cases related to smoking in Indonesia numbered 45,132, accounting for 35,580 cancer deaths. The morbidity and mortality of lung cancer can be considered as the highest priority in both men and women. Furthermore the greatest YLD due to smoking in Indonesian men and women were from pancreas and lung cancers. For YLL among men, the highest years lost were from lung and liver cancers. On the other hand, among women lung oral cavity and lip were most important. Based on the DALY indicator, burden priorities for Indonesian men were lung cancer (298,980), liver cancer (60,367), and nasopharynx (46,185), while among Indonesian women they were lung cancer (34,119), cervix uteri (9,213) and pancreas cancer (5,433). In total, Indonesian burden of cancers attributed to smoking was 638,682 DALY. This study provides evidence about the burden of cancers caused by smoking as a rational basis for initiating national tobacco control policies in Indonesia. PMID:27039808

  10. Adjustment of lifetime risks of space radiation-induced cancer by the healthy worker effect and cancer misclassification.

    PubMed

    Peterson, Leif E; Kovyrshina, Tatiana

    2015-12-01

    Background. The healthy worker effect (HWE) is a source of bias in occupational studies of mortality among workers caused by use of comparative disease rates based on public data, which include mortality of unhealthy members of the public who are screened out of the workplace. For the US astronaut corp, the HWE is assumed to be strong due to the rigorous medical selection and surveillance. This investigation focused on the effect of correcting for HWE on projected lifetime risk estimates for radiation-induced cancer mortality and incidence. Methods. We performed radiation-induced cancer risk assessment using Poisson regression of cancer mortality and incidence rates among Hiroshima and Nagasaki atomic bomb survivors. Regression coefficients were used for generating risk coefficients for the excess absolute, transfer, and excess relative models. Excess lifetime risks (ELR) for radiation exposure and baseline lifetime risks (BLR) were adjusted for the HWE using standardized mortality ratios (SMR) for aviators and nuclear workers who were occupationally exposed to ionizing radiation. We also adjusted lifetime risks by cancer mortality misclassification among atomic bomb survivors. Results. For all cancers combined ("Nonleukemia"), the effect of adjusting the all-cause hazard rate by the simulated quantiles of the all-cause SMR resulted in a mean difference (not percent difference) in ELR of 0.65% and mean difference of 4% for mortality BLR, and mean change of 6.2% in BLR for incidence. The effect of adjusting the excess (radiation-induced) cancer rate or baseline cancer hazard rate by simulated quantiles of cancer-specific SMRs resulted in a mean difference of [Formula: see text] in the all-cancer mortality ELR and mean difference of [Formula: see text] in the mortality BLR. Whereas for incidence, the effect of adjusting by cancer-specific SMRs resulted in a mean change of [Formula: see text] for the all-cancer BLR. Only cancer mortality risks were adjusted by

  11. REVIEW OF DRAFT REVISED BLUE BOOK ON ESTIMATING CANCER RISKS FROM EXPOSURE TO IONIZING RADIATION

    EPA Science Inventory

    In 1994, EPA published a report, referred to as the “Blue Book,” which lays out EPA’s current methodology for quantitatively estimating radiogenic cancer risks. A follow-on report made minor adjustments to the previous estimates and presented a partial analysis of the uncertainti...

  12. Baseline Estimation Algorithm with Block Adjustment for Multi-Pass Dual-Antenna Insar

    NASA Astrophysics Data System (ADS)

    Jin, Guowang; Xiong, Xin; Xu, Qing; Gong, Zhihui; Zhou, Yang

    2016-06-01

    Baseline parameters and interferometric phase offset need to be estimated accurately, for they are key parameters in processing of InSAR (Interferometric Synthetic Aperture Radar). If adopting baseline estimation algorithm with single pass, it needs large quantities of ground control points to estimate interferometric parameters for mosaicking multiple passes dual-antenna airborne InSAR data that covers large areas. What's more, there will be great difference between heights derived from different passes due to the errors of estimated parameters. So, an estimation algorithm of interferometric parameters with block adjustment for multi-pass dual-antenna InSAR is presented to reduce the needed ground control points and height's difference between different passes. The baseline estimation experiments were done with multi-pass InSAR data obtained by Chinese dual-antenna airborne InSAR system. Although there were less ground control points, the satisfied results were obtained, as validated the proposed baseline estimation algorithm.

  13. Does exposure prediction bias health effect estimation? The relationship between confounding adjustment and exposure prediction

    PubMed Central

    Dominici, Francesca

    2014-01-01

    In environmental epidemiology, we are often faced with two challenges. First, an exposure prediction model is needed to estimate the exposure to an agent of interest, ideally at the individual level. Second, when estimating the health-effect associated with the exposure, confounding adjustment is needed in the health-effects regression model. The current literature addresses these two challenges separately. That is, methods that account for measurement error in the predicted exposure often fail to acknowledge the possibility of confounding, while methods designed to control confounding often fail to acknowledge that the exposure has been predicted. In this paper, we consider exposure prediction and confounding adjustment in a health-effects regression model simultaneously. By using theoretical arguments and simulation studies, we show that the bias of a health-effect estimate is influenced by the exposure prediction model, the type of confounding adjustment used in the health-effects regression model, and the relationship between these two. Moreover, we argue that even with a health-effects regression model that properly adjusts for confounding, the use of a predicted exposure can bias the health-effect estimate unless all confounders included in the health-effects regression model are also included in the exposure prediction model. While these results of this paper were motivated by studies of environmental contaminants, they apply more broadly to any context where an exposure needs to be predicted. PMID:24815302

  14. Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR).

    PubMed

    Evans, Scott R; Rubin, Daniel; Follmann, Dean; Pennello, Gene; Huskins, W Charles; Powers, John H; Schoenfeld, David; Chuang-Stein, Christy; Cosgrove, Sara E; Fowler, Vance G; Lautenbach, Ebbing; Chambers, Henry F

    2015-09-01

    Clinical trials that compare strategies to optimize antibiotic use are of critical importance but are limited by competing risks that distort outcome interpretation, complexities of noninferiority trials, large sample sizes, and inadequate evaluation of benefits and harms at the patient level. The Antibacterial Resistance Leadership Group strives to overcome these challenges through innovative trial design. Response adjusted for duration of antibiotic risk (RADAR) is a novel methodology utilizing a superiority design and a 2-step process: (1) categorizing patients into an overall clinical outcome (based on benefits and harms), and (2) ranking patients with respect to a desirability of outcome ranking (DOOR). DOORs are constructed by assigning higher ranks to patients with (1) better overall clinical outcomes and (2) shorter durations of antibiotic use for similar overall clinical outcomes. DOOR distributions are compared between antibiotic use strategies. The probability that a randomly selected patient will have a better DOOR if assigned to the new strategy is estimated. DOOR/RADAR represents a new paradigm in assessing the risks and benefits of new strategies to optimize antibiotic use. PMID:26113652

  15. Risk Estimation Methodology for Launch Accidents.

    SciTech Connect

    Clayton, Daniel James; Lipinski, Ronald J.; Bechtel, Ryan D.

    2014-02-01

    As compact and light weight power sources with reliable, long lives, Radioisotope Power Systems (RPSs) have made space missions to explore the solar system possible. Due to the hazardous material that can be released during a launch accident, the potential health risk of an accident must be quantified, so that appropriate launch approval decisions can be made. One part of the risk estimation involves modeling the response of the RPS to potential accident environments. Due to the complexity of modeling the full RPS response deterministically on dynamic variables, the evaluation is performed in a stochastic manner with a Monte Carlo simulation. The potential consequences can be determined by modeling the transport of the hazardous material in the environment and in human biological pathways. The consequence analysis results are summed and weighted by appropriate likelihood values to give a collection of probabilistic results for the estimation of the potential health risk. This information is used to guide RPS designs, spacecraft designs, mission architecture, or launch procedures to potentially reduce the risk, as well as to inform decision makers of the potential health risks resulting from the use of RPSs for space missions.

  16. Estimating contaminant loads in rivers: An application of adjusted maximum likelihood to type 1 censored data

    USGS Publications Warehouse

    Cohn, T.A.

    2005-01-01

    This paper presents an adjusted maximum likelihood estimator (AMLE) that can be used to estimate fluvial transport of contaminants, like phosphorus, that are subject to censoring because of analytical detection limits. The AMLE is a generalization of the widely accepted minimum variance unbiased estimator (MVUE), and Monte Carlo experiments confirm that it shares essentially all of the MVUE's desirable properties, including high efficiency and negligible bias. In particular, the AMLE exhibits substantially less bias than alternative censored-data estimators such as the MLE (Tobit) or the MLE followed by a jackknife. As with the MLE and the MVUE the AMLE comes close to achieving the theoretical Frechet-Crame??r-Rao bounds on its variance. This paper also presents a statistical framework, applicable to both censored and complete data, for understanding and estimating the components of uncertainty associated with load estimates. This can serve to lower the cost and improve the efficiency of both traditional and real-time water quality monitoring.

  17. Estimation and adjustment of self-selection bias in volunteer panel web surveys

    NASA Astrophysics Data System (ADS)

    Niu, Chengying

    2016-06-01

    By using propensity score matching method of random sample, we matched simple random sample units and volunteer panel Web survey sample units based on the equal or similar propensity score. The unbiased estimators of the population parameters are constructed by using the matching simple random sample, and the self-selection bias is estimated. We propose propensity score weighted and matching sample post stratification weighted methods to estimate the population parameters, and the self-selection bias in volunteer panel Web Surveys are adjusted.

  18. Improved hospital-level risk adjustment for surveillance of healthcare-associated bloodstream infections: a retrospective cohort study

    PubMed Central

    2009-01-01

    Background To allow direct comparison of bloodstream infection (BSI) rates between hospitals for performance measurement, observed rates need to be risk adjusted according to the types of patients cared for by the hospital. However, attribute data on all individual patients are often unavailable and hospital-level risk adjustment needs to be done using indirect indicator variables of patient case mix, such as hospital level. We aimed to identify medical services associated with high or low BSI rates, and to evaluate the services provided by the hospital as indicators that can be used for more objective hospital-level risk adjustment. Methods From February 2001-December 2007, 1719 monthly BSI counts were available from 18 hospitals in Queensland, Australia. BSI outcomes were stratified into four groups: overall BSI (OBSI), Staphylococcus aureus BSI (STAPH), intravascular device-related S. aureus BSI (IVD-STAPH) and methicillin-resistant S. aureus BSI (MRSA). Twelve services were considered as candidate risk-adjustment variables. For OBSI, STAPH and IVD-STAPH, we developed generalized estimating equation Poisson regression models that accounted for autocorrelation in longitudinal counts. Due to a lack of autocorrelation, a standard logistic regression model was specified for MRSA. Results Four risk services were identified for OBSI: AIDS (IRR 2.14, 95% CI 1.20 to 3.82), infectious diseases (IRR 2.72, 95% CI 1.97 to 3.76), oncology (IRR 1.60, 95% CI 1.29 to 1.98) and bone marrow transplants (IRR 1.52, 95% CI 1.14 to 2.03). Four protective services were also found. A similar but smaller group of risk and protective services were found for the other outcomes. Acceptable agreement between observed and fitted values was found for the OBSI and STAPH models but not for the IVD-STAPH and MRSA models. However, the IVD-STAPH and MRSA models successfully discriminated between hospitals with higher and lower BSI rates. Conclusion The high model goodness-of-fit and the higher

  19. Applying propensity scores estimated in a full cohort to adjust for confounding in subgroup analyses

    PubMed Central

    Rassen, Jeremy A.; Glynn, Robert J.; Rothman, Kenneth J.; Setoguchi, Soko; Schneeweiss, Sebastian

    2012-01-01

    A correctly-specified propensity score (PS) estimated in a cohort (“cohort PS”) should in expectation remain valid in a subgroup population. We sought to determine whether using a cohort PS can be validly applied to subgroup analyses and thus add efficiency to studies with many subgroups or restricted data. In each of 3 cohort studies we estimated a cohort PS, defined 5 subgroups, and then estimated subgroup-specific PSs. We compared difference in treatment effect estimates for subgroup analyses adjusted by cohort PSs versus subgroup-specific PSs. Then, 10M times, we simulated a population with known characteristics of confounding, subgroup size, treatment interactions, and treatment effect, and again assessed difference in point estimates. We observed that point estimates in most subgroups were substantially similar with the two methods of adjustment. In simulations, the effect estimates differed by a median of 3.4% (interquartile [IQ] range 1.3% to 10.0%). The IQ range exceeded 10% only in cases where the subgroup had <1000 patients or few outcome events. Our empirical and simulation results indicated that using a cohort PS in subgroup analyses was a feasible approach, particularly in larger subgroups. PMID:22162077

  20. Bias-adjusted satellite-based rainfall estimates for predicting floods: Narayani Basin

    USGS Publications Warehouse

    Artan, Guleid A.; Tokar, S.A.; Gautam, D.K.; Bajracharya, S.R.; Shrestha, M.S.

    2011-01-01

    In Nepal, as the spatial distribution of rain gauges is not sufficient to provide detailed perspective on the highly varied spatial nature of rainfall, satellite-based rainfall estimates provides the opportunity for timely estimation. This paper presents the flood prediction of Narayani Basin at the Devghat hydrometric station (32 000 km2) using bias-adjusted satellite rainfall estimates and the Geospatial Stream Flow Model (GeoSFM), a spatially distributed, physically based hydrologic model. The GeoSFM with gridded gauge observed rainfall inputs using kriging interpolation from 2003 was used for calibration and 2004 for validation to simulate stream flow with both having a Nash Sutcliff Efficiency of above 0.7. With the National Oceanic and Atmospheric Administration Climate Prediction Centre's rainfall estimates (CPC_RFE2.0), using the same calibrated parameters, for 2003 the model performance deteriorated but improved after recalibration with CPC_RFE2.0 indicating the need to recalibrate the model with satellite-based rainfall estimates. Adjusting the CPC_RFE2.0 by a seasonal, monthly and 7-day moving average ratio, improvement in model performance was achieved. Furthermore, a new gauge-satellite merged rainfall estimates obtained from ingestion of local rain gauge data resulted in significant improvement in flood predictability. The results indicate the applicability of satellite-based rainfall estimates in flood prediction with appropriate bias correction.

  1. Nonparametric estimation with recurrent competing risks data

    PubMed Central

    Peña, Edsel A.

    2014-01-01

    Nonparametric estimators of component and system life distributions are developed and presented for situations where recurrent competing risks data from series systems are available. The use of recurrences of components’ failures leads to improved efficiencies in statistical inference, thereby leading to resource-efficient experimental or study designs or improved inferences about the distributions governing the event times. Finite and asymptotic properties of the estimators are obtained through simulation studies and analytically. The detrimental impact of parametric model misspecification is also vividly demonstrated, lending credence to the virtue of adopting nonparametric or semiparametric models, especially in biomedical settings. The estimators are illustrated by applying them to a data set pertaining to car repairs for vehicles that were under warranty. PMID:24072583

  2. Auditory risk estimates for youth target shooting

    PubMed Central

    Meinke, Deanna K.; Murphy, William J.; Finan, Donald S.; Lankford, James E.; Flamme, Gregory A.; Stewart, Michael; Soendergaard, Jacob; Jerome, Trevor W.

    2015-01-01

    Objective To characterize the impulse noise exposure and auditory risk for youth recreational firearm users engaged in outdoor target shooting events. The youth shooting positions are typically standing or sitting at a table, which places the firearm closer to the ground or reflective surface when compared to adult shooters. Design Acoustic characteristics were examined and the auditory risk estimates were evaluated using contemporary damage-risk criteria for unprotected adult listeners and the 120-dB peak limit suggested by the World Health Organization (1999) for children. Study sample Impulses were generated by 26 firearm/ammunition configurations representing rifles, shotguns, and pistols used by youth. Measurements were obtained relative to a youth shooter’s left ear. Results All firearms generated peak levels that exceeded the 120 dB peak limit suggested by the WHO for children. In general, shooting from the seated position over a tabletop increases the peak levels, LAeq8 and reduces the unprotected maximum permissible exposures (MPEs) for both rifles and pistols. Pistols pose the greatest auditory risk when fired over a tabletop. Conclusion Youth should utilize smaller caliber weapons, preferably from the standing position, and always wear hearing protection whenever engaging in shooting activities to reduce the risk for auditory damage. PMID:24564688

  3. Child effects and child care: Implications for risk and adjustment.

    PubMed

    Snell, Emily K; Hindman, Annemarie H; Belsky, Jay

    2015-11-01

    Evocative effects of child characteristics on the quality and quantity of child care were assessed in two studies using longitudinal data from the NICHD Study of Early Child Care. We focus on the influence of child characteristics on two important aspects of the child care experience: language stimulation provided by caregivers and quantity of care. In Study 1, associations between the developmental status of children aged 15 to 54 months and the language stimulation provided by their caregivers were examined using path models, and longitudinal child effects were detected across the earliest time points of the study. In Study 2, the associations among child behavior, temperament, development, and time in care were examined. Little evidence was found for such child effects on time in care. The results are discussed in terms of the effects of child care on child development and implications for developmental processes, particularly for children at greatest risk for developmental delay or psychopathology. PMID:26439062

  4. Slope Estimation of Covariates that Influence Renal Outcome following Renal Transplant Adjusting for Informative Right Censoring

    PubMed Central

    Jaffa, Miran A.; Jaffa, Ayad A; Lipsitz, Stuart R.

    2015-01-01

    A new statistical model is proposed to estimate population and individual slopes that are adjusted for covariates and informative right censoring. Individual slopes are assumed to have a mean that depends on the population slope for the covariates. The number of observations for each individual is modeled as a truncated discrete distribution with mean dependent on the individual subjects' slopes. Our simulation study results indicated that the associated bias and mean squared errors for the proposed model were comparable to those associated with the model that only adjusts for informative right censoring. The proposed model was illustrated using renal transplant dataset to estimate population slopes for covariates that could impact the outcome of renal function following renal transplantation. PMID:25729124

  5. Volcanic risk perception and adjustment in a multi-hazard environment

    NASA Astrophysics Data System (ADS)

    Perry, Ronald W.; Lindell, Michael K.

    2008-05-01

    Hazard risk perceptions and protective behaviors are examined for wildfires, earthquakes and volcanic activity. Data were gathered in two northern California (USA) communities that are exposed to all three hazard types. It was found that resident risk perceptions approximated the risks calculated by experts. Personal risks associated with fires were significantly lower than property risks associated with the same threat. The discrepancy between person and property risks for earthquakes and volcanic activity was much smaller. In general, it was found that the number of protective adjustments undertaken for each hazard was small (averaging about half of the possible number measured). When combined in a regression analysis, risk perception was not a statistically significant predictor of number of adjustments for any of the three hazards. Resident's sense of responsibility for self-protection and experience with property damage were significant predictors of adjustment for all three hazards. Information seeking behavior was significantly related to protective actions for earthquakes and volcanic activity, but not for fire hazards. In general, an insufficient number of residents reported experience with personal injury or harm to make meaningful assessments of the effect of this variable on adjustments.

  6. Extreme Earthquake Risk Estimation by Hybrid Modeling

    NASA Astrophysics Data System (ADS)

    Chavez, M.; Cabrera, E.; Ashworth, M.; Garcia, S.; Emerson, D.; Perea, N.; Salazar, A.; Moulinec, C.

    2012-12-01

    The estimation of the hazard and the economical consequences i.e. the risk associated to the occurrence of extreme magnitude earthquakes in the neighborhood of urban or lifeline infrastructure, such as the 11 March 2011 Mw 9, Tohoku, Japan, represents a complex challenge as it involves the propagation of seismic waves in large volumes of the earth crust, from unusually large seismic source ruptures up to the infrastructure location. The large number of casualties and huge economic losses observed for those earthquakes, some of which have a frequency of occurrence of hundreds or thousands of years, calls for the development of new paradigms and methodologies in order to generate better estimates, both of the seismic hazard, as well as of its consequences, and if possible, to estimate the probability distributions of their ground intensities and of their economical impacts (direct and indirect losses), this in order to implement technological and economical policies to mitigate and reduce, as much as possible, the mentioned consequences. Herewith, we propose a hybrid modeling which uses 3D seismic wave propagation (3DWP) and neural network (NN) modeling in order to estimate the seismic risk of extreme earthquakes. The 3DWP modeling is achieved by using a 3D finite difference code run in the ~100 thousands cores Blue Gene Q supercomputer of the STFC Daresbury Laboratory of UK, combined with empirical Green function (EGF) techniques and NN algorithms. In particular the 3DWP is used to generate broadband samples of the 3D wave propagation of extreme earthquakes (plausible) scenarios corresponding to synthetic seismic sources and to enlarge those samples by using feed-forward NN. We present the results of the validation of the proposed hybrid modeling for Mw 8 subduction events, and show examples of its application for the estimation of the hazard and the economical consequences, for extreme Mw 8.5 subduction earthquake scenarios with seismic sources in the Mexican

  7. NEED FOR INDIVIDUAL CANCER RISK ESTIMATES IN X-RAY AND NUCLEAR MEDICINE IMAGING.

    PubMed

    Mattsson, Sören

    2016-06-01

    To facilitate the justification of an X-ray or nuclear medicine investigation and for informing patients, it is desirable that the individual patient's radiation dose and potential cancer risk can be prospectively assessed and documented. The current dose-reporting is based on effective dose, which ignores body size and does not reflect the strong dependence of risk on the age at exposure. Risk estimations should better be done through individual organ dose assessments, which need careful exposure characterisation as well as anatomical description of the individual patient. In nuclear medicine, reference biokinetic models should also be replaced with models describing individual physiological states and biokinetics. There is a need to adjust population-based cancer risk estimates to the possible risk of leukaemia and solid tumours for the individual depending on age and gender. The article summarises reasons for individual cancer risk estimates and gives examples of methods and results of such estimates. PMID:26994092

  8. The Experience of Risk-Adjusted Capitation Payment for Family Physicians in Iran: A Qualitative Study

    PubMed Central

    Esmaeili, Reza; Hadian, Mohammad; Rashidian, Arash; Shariati, Mohammad; Ghaderi, Hossien

    2016-01-01

    Background When a country’s health system is faced with fundamental flaws that require the redesign of financing and service delivery, primary healthcare payment systems are often reformed. Objectives This study was conducted with the purpose of exploring the experiences of risk-adjusted capitation payment of urban family physicians in Iran when it comes to providing primary health care (PHC). Materials and Methods This is a qualitative study using the framework method. Data were collected via digitally audio-recorded semi-structured interviews with 24 family physicians and 5 executive directors in two provinces of Iran running the urban family physician pilot program. The participants were selected using purposive and snowball sampling. The codes were extracted using inductive and deductive methods. Results Regarding the effects of risk-adjusted capitation on the primary healthcare setting, five themes with 11 subthemes emerged, including service delivery, institutional structure, financing, people’s behavior, and the challenges ahead. Our findings indicated that the health system is enjoying some major changes in the primary healthcare setting through the implementation of risk-adjusted capitation payment. Conclusions With regard to the current challenges in Iran’s health system, using risk-adjusted capitation as a primary healthcare payment system can lead to useful changes in the health system’s features. However, future research should focus on the development of the risk-adjusted capitation model. PMID:27340558

  9. REFAME: Rain Estimation Using Forward Adjusted-Advection of Microwave Estimates

    NASA Technical Reports Server (NTRS)

    Behrangi, Ali; Imam, Bisher; Hsu, Kuolin; Sorooshian, Soroosh; Bellerby, Timothy J.

    2009-01-01

    Sensors flying on satellites provide the only practical means of estimating the precipitation that falls over the entire globe, particularly across the vast unpopulated expanses of Earth s oceans. The sensors that observe the Earth using microwave frequencies provide the best data, but currently these are mounted only on satellites flying in "low Earth orbit". Such satellites constantly move across the Earth s surface, providing snapshots of any given location every 12-36 hours. The entire constellation of low-orbit satellites numbers less than a dozen, and their orbits are not coordinated, so a location will frequently go two or more hours between snapshots. "Geosynchronous Earth orbit" (GEO) satellites continuously observe the same region of the globe, allowing them to provide very frequent pictures. For example, the "satellite movies" shown on television come from GEO satellites. However, the sensors available on GEO satellites cannot match the skill of the low-orbit microwave sensors in estimating precipitation. It is perhaps obvious that scientists should try to combine these very different kinds of data, taking advantage of the strengths of each, but this simple concept has proved to be a huge challenge. The scheme in this paper is "Lagrangian", meaning we follow the storm systems, rather than being tied to a fixed grid of boxes on the Earth s surface. Whenever a microwave snapshot occurs, we gladly use the resulting precipitation estimate. Then at all the times between the microwave snapshots we force the storm system to make a smooth transition from one snapshot s values to the next. We know that a lot more changes occur between the snapshots, but this smooth transition the best we can do with the microwave data alone. The key new contribution in this paper is that we also look at the relative variations in the GEO estimates during these in-between times and force the estimated changes in the precipitation to have similar variations. Preliminary testing

  10. Reexamination of spent fuel shipment risk estimates

    SciTech Connect

    COOK,J.R.; SPRUNG,JEREMY L.

    2000-04-25

    The risks associated with the transport of spent nuclear fuel by truck and rail have been reexamined and compared to results published in NUREG-O170 and the Modal Study. The full reexamination considered transport of PWR and BWR spent fuel by truck and rail in four generic Type B spent fuel casks. Because they are typical, this paper presents results only for transport of PWR spent fuel in steel-lead steel casks. Cask and spent fuel response to collision impacts and fires were evaluated by performing three-dimensional finite element and one-dimensional heat transport calculations. Accident release fractions were developed by critical review of literature data. Accident severity fractions were developed from Modal Study truck and rail accident event trees, modified to reflect the frequency of occurrence of hard and soft rock wayside route surfaces as determined by analysis of geographic data. Incident-free population doses and the population dose risks associated with the accidents that might occur during transport were calculated using the RADTRAN 5 transportation risk code. The calculated incident-free doses were compared to those published in NUREG-O170. The calculated accident dose risks were compared to dose risks calculated using NUREG-0170 and Modal Study accident source terms. The comparisons demonstrated that both of these studies made a number of very conservative assumptions about spent fuel and cask response to accident conditions, which caused their estimates of accident source terms, accident frequencies, and accident consequences to also be very conservative. The results of this study and the previous studies demonstrate that the risks associated with the shipment of spent fuel by truck or rail are very small.

  11. Methodology for estimating extreme winds for probabilistic risk assessments

    SciTech Connect

    Ramsdell, J.V.; Elliott, D.L.; Holladay, C.G.; Hubbe, J.M.

    1986-10-01

    The US Nuclear Reguulatory Commission (NRC) assesses the risks associated with nuclear faciliies using techniques that fall under a generic name of Probabilistic Risk Assessment. In these assessments, potential accident sequences are traced from initiating event to final outcome. At each step of the sequence, a probability of occurrence is assigned to each available alternative. Ultimately, the probability of occurrence of each possible outcome is determined from the probabilities assigned to the initiating events and the alternative paths. Extreme winds are considered in these sequences. As a result, it is necessary to estimate extreme wind probabilities as low as 10/sup -7/yr/sup -1/. When the NRC staff is called on to provide extreme wind estimates, the staff is likely to be subjected to external time and funding constraints. These constraints dictate that the estimates be based on readily available wind data. In general, readily available data will be limited to the data provided by the facility applicant or licensee and the data archived at the National Climatic Data Center in Asheville, North Carolina. This report describes readily available data that can be used in estimating extreme wind probabilities, procedures of screening the data to eliminate erroneous values and for adjusting data to compensate for differences in data collection methods, and statistical methods for making extreme wind estimates. Supporting technical details are presented in several appendices. Estimation of extreme wind probabilities at a given location involves many subjective decisions. The procedures described do not eliminate all of the subjectivity, but they do increase the reproducibility of the analysis. They provide consistent methods for determining probabilities given a set of subjective decisions. By following these procedures, subjective decisions can be identified and documented.

  12. Relating space radiation environments to risk estimates

    NASA Technical Reports Server (NTRS)

    Curtis, Stanley B.

    1993-01-01

    A number of considerations must go into the process of determining the risk of deleterious effects of space radiation to travelers. Among them are (1) determination of the components of the radiation environment (particle species, fluxes and energy spectra) which will encounter, (2) determination of the effects of shielding provided by the spacecraft and the bodies of the travelers which modify the incident particle spectra and mix of particles, and (3) determination of relevant biological effects of the radiation in the organs of interest. The latter can then lead to an estimation of risk from a given space scenario. Clearly, the process spans many scientific disciplines from solar and cosmic ray physics to radiation transport theeory to the multistage problem of the induction by radiation of initial lesions in living material and their evolution via physical, chemical, and biological processes at the molecular, cellular, and tissue levels to produce the end point of importance.

  13. Relating space radiation environments to risk estimates

    SciTech Connect

    Curtis, S.B. ||

    1993-12-31

    A number of considerations must go into the process of determining the risk of deleterious effects of space radiation to travelers. Among them are (1) determination of the components of the radiation environment (particle species, fluxes and energy spectra) which will encounter, (2) determination of the effects of shielding provided by the spacecraft and the bodies of the travelers which modify the incident particle spectra and mix of particles, and (3) determination of relevant biological effects of the radiation in the organs of interest. The latter can then lead to an estimation of risk from a given space scenario. Clearly, the process spans many scientific disciplines from solar and cosmic ray physics to radiation transport theeory to the multistage problem of the induction by radiation of initial lesions in living material and their evolution via physical, chemical, and biological processes at the molecular, cellular, and tissue levels to produce the end point of importance.

  14. Climate-informed flood risk estimation

    NASA Astrophysics Data System (ADS)

    Troy, T.; Devineni, N.; Lima, C.; Lall, U.

    2013-12-01

    Currently, flood risk assessments are typically tied to a peak flow event that has an associated return period and inundation extent. This method is convenient: based on a historical record of annual maximum flows, a return period can be calculated with some assumptions about the probability distribution and stationarity. It is also problematic in its stationarity assumption, reliance on relatively short records, and treating flooding as a random event disconnected from large-scale climate processes. Recognizing these limitations, we have developed a new approach to flood risk assessment that connects climate variability, precipitation dynamics, and flood modeling to estimate the likelihood of flooding. To provide more robust, long time series of precipitation, we used stochastic weather generator models to simulate the rainfall fields. The method uses a k-nearest neighbor resampling algorithm in conjunction with a non-parametric empirical copulas based simulation strategy to reproduce the temporal and spatial dynamics, respectively. Climate patterns inform the likelihood of heavy rainfall in the model. For example, ENSO affects the likelihood of wet or dry years in Australia, and this is incorporated in the model. The stochastic simulations are then used to drive a cascade of models to predict flood inundation. Runoff is generated by the Variable Infiltration Capacity (VIC) model, fed into a full kinematic wave routing model at high resolution, and the kinematic wave is used as a boundary condition to predict flood inundation using a coupled storage cell model. Combining the strengths of a stochastic model for rainfall and a physical model for flood prediction allows us to overcome the limitations of traditional flood risk assessment and provide robust estimates of flood risk.

  15. Potential of adjustable height carts in reducing the risk of low back injury in grocery stockers.

    PubMed

    Davis, Kermit G; Orta Anés, Lida

    2014-03-01

    While the workers of the Wholesale and Retail Trade industrial sector suffer from musculoskeletal disorders at an alarming rate, there have been few investigative studies into potential effective interventions to reduce the ergonomic stress. The objective of the study was to determine whether a cart with an adjustable shelf could reduce awkward postures and motions while stocking products in a grocery store. Fifteen workers at a small grocery store in Puerto Rico completed stocking tasks with two types of carts: traditional and adjustable height cart or Ergo Cart. Trunk kinematics, LBD risk index, NIOSH lifting index, subjective ratings, and productivity indicators were collected during four typical stocking tasks. The Adjustable Ergo Cart reduced the sagittal trunk flexion by 7° and velocity by about 5°/s but increased twisting by about 2° and twist velocity by 4°/s as compared to the traditional cart. The LBD risk index was reduced by a small 2.4% in probability although greater reductions were found for larger items (e.g. bags of dog food and 2-L of Soda). The consensus among workers was that the adjustable cart would be easier to use. Overall, the study provides objective evidence that an ergonomically designed cart (e.g. adjustable height) has some potential to reduce sagittal trunk flexion, LBD risk index, and the NIOSH lift index. Overall, the results indicate that any intervention such as an adjustable cart can only have marginal effectiveness unless the entire systems perspective is considered. PMID:23664243

  16. Dynamic probability control limits for risk-adjusted Bernoulli CUSUM charts.

    PubMed

    Zhang, Xiang; Woodall, William H

    2015-11-10

    The risk-adjusted Bernoulli cumulative sum (CUSUM) chart developed by Steiner et al. (2000) is an increasingly popular tool for monitoring clinical and surgical performance. In practice, however, the use of a fixed control limit for the chart leads to a quite variable in-control average run length performance for patient populations with different risk score distributions. To overcome this problem, we determine simulation-based dynamic probability control limits (DPCLs) patient-by-patient for the risk-adjusted Bernoulli CUSUM charts. By maintaining the probability of a false alarm at a constant level conditional on no false alarm for previous observations, our risk-adjusted CUSUM charts with DPCLs have consistent in-control performance at the desired level with approximately geometrically distributed run lengths. Our simulation results demonstrate that our method does not rely on any information or assumptions about the patients' risk distributions. The use of DPCLs for risk-adjusted Bernoulli CUSUM charts allows each chart to be designed for the corresponding particular sequence of patients for a surgeon or hospital. PMID:26037959

  17. Continuing bonds, risk factors for complicated grief, and adjustment to bereavement.

    PubMed

    Field, Nigel P; Filanosky, Charles

    2010-01-01

    This study examined type of continuing bonds (CB) expression in relation to risk factors for complicated grief and measures of bereavement-related adjustment. Externalized CB expressions involving illusions and hallucinations with the deceased were distinguished from internalized CB expressions involving use of the deceased as an autonomy promoting secure base. 502 bereaved participants completed over the internet a CB measure assessing externalized and internalized CB along with various known risk-factor measures that included cause of death (i.e., violent vs. non-violent death), responsibility for the death, and attachment style as well as measures of psychological adjustment that included complicated grief symptoms, perceived physical health, and personal growth. As predicted, externalized CB was positively associated with violent death and responsibility for the death, whereas internalized CB was negatively associated with these risk factors as well as uniquely positively linked to personal growth. The implications of the findings for the role of CB in adjustment are discussed. PMID:24479173

  18. Launch Risk Acceptability Considering Uncertainty in Risk Estimates

    NASA Astrophysics Data System (ADS)

    Collins, J. D.; Carbon, S. L.

    2010-09-01

    Quantification of launch risk is difficult and uncertain due to the assumptions made in the modeling process and the difficulty in developing the supporting data. This means that estimates of the risks are uncertain and the decision maker must decide on the acceptability of the launch under uncertainty. This paper describes the process to quantify the uncertainty and, in the process, describes the separate roles of aleatory and epistemic uncertainty in obtaining the point estimate of the casualty expectation and, ultimately, the distribution of the uncertainty in the computed casualty expectation. Tables are included of the significant sources and the nature of the contributing uncertainties. In addition, general procedures and an example are also included to describe the computational procedure. The second part of the paper discusses how the quantified uncertainty should be applied to the decision-making process. This discussion describes the procedure proposed and adopted by the Risk Committee of the Range Commander’s Council Range Safety Group which will be published in RCC 321-10 [1].

  19. The HHS-HCC Risk Adjustment Model for Individual and Small Group Markets under the Affordable Care Act

    PubMed Central

    Kautter, John; Pope, Gregory C; Ingber, Melvin; Freeman, Sara; Patterson, Lindsey; Cohen, Michael; Keenan, Patricia

    2014-01-01

    Beginning in 2014, individuals and small businesses are able to purchase private health insurance through competitive Marketplaces. The Affordable Care Act (ACA) provides for a program of risk adjustment in the individual and small group markets in 2014 as Marketplaces are implemented and new market reforms take effect. The purpose of risk adjustment is to lessen or eliminate the influence of risk selection on the premiums that plans charge. The risk adjustment methodology includes the risk adjustment model and the risk transfer formula. This article is the second of three in this issue of the Review that describe the Department of Health and Human Services (HHS) risk adjustment methodology and focuses on the risk adjustment model. In our first companion article, we discuss the key issues and choices in developing the methodology. In this article, we present the risk adjustment model, which is named the HHS-Hierarchical Condition Categories (HHS-HCC) risk adjustment model. We first summarize the HHS-HCC diagnostic classification, which is the key element of the risk adjustment model. Then the data and methods, results, and evaluation of the risk adjustment model are presented. Fifteen separate models are developed. For each age group (adult, child, and infant), a model is developed for each cost sharing level (platinum, gold, silver, and bronze metal levels, as well as catastrophic plans). Evaluation of the risk adjustment models shows good predictive accuracy, both for individuals and for groups. Lastly, this article provides examples of how the model output is used to calculate risk scores, which are an input into the risk transfer formula. Our third companion paper describes the risk transfer formula. PMID:25360387

  20. The HHS-HCC risk adjustment model for individual and small group markets under the Affordable Care Act.

    PubMed

    Kautter, John; Pope, Gregory C; Ingber, Melvin; Freeman, Sara; Patterson, Lindsey; Cohen, Michael; Keenan, Patricia

    2014-01-01

    Beginning in 2014, individuals and small businesses are able to purchase private health insurance through competitive Marketplaces. The Affordable Care Act (ACA) provides for a program of risk adjustment in the individual and small group markets in 2014 as Marketplaces are implemented and new market reforms take effect. The purpose of risk adjustment is to lessen or eliminate the influence of risk selection on the premiums that plans charge. The risk adjustment methodology includes the risk adjustment model and the risk transfer formula. This article is the second of three in this issue of the Review that describe the Department of Health and Human Services (HHS) risk adjustment methodology and focuses on the risk adjustment model. In our first companion article, we discuss the key issues and choices in developing the methodology. In this article, we present the risk adjustment model, which is named the HHS-Hierarchical Condition Categories (HHS-HCC) risk adjustment model. We first summarize the HHS-HCC diagnostic classification, which is the key element of the risk adjustment model. Then the data and methods, results, and evaluation of the risk adjustment model are presented. Fifteen separate models are developed. For each age group (adult, child, and infant), a model is developed for each cost sharing level (platinum, gold, silver, and bronze metal levels, as well as catastrophic plans). Evaluation of the risk adjustment models shows good predictive accuracy, both for individuals and for groups. Lastly, this article provides examples of how the model output is used to calculate risk scores, which are an input into the risk transfer formula. Our third companion paper describes the risk transfer formula. PMID:25360387

  1. Estimating the risk of Amazonian forest dieback.

    PubMed

    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. PMID:20553387

  2. Software risk estimation and management techniques at JPL

    NASA Technical Reports Server (NTRS)

    Hihn, J.; Lum, K.

    2002-01-01

    In this talk we will discuss how uncertainty has been incorporated into the JPL software model, probabilistic-based estimates, and how risk is addressed, how cost risk is currently being explored via a variety of approaches, from traditional risk lists, to detailed WBS-based risk estimates to the Defect Detection and Prevention (DDP) tool.

  3. A population health approach to reducing observational intensity bias in health risk adjustment: cross sectional analysis of insurance claims

    PubMed Central

    Sharp, Sandra M; Bevan, Gwyn; Skinner, Jonathan S; Gottlieb, Daniel J

    2014-01-01

    Objective To compare the performance of two new approaches to risk adjustment that are free of the influence of observational intensity with methods that depend on diagnoses listed in administrative databases. Setting Administrative data from the US Medicare program for services provided in 2007 among 306 US hospital referral regions. Design Cross sectional analysis. Participants 20% sample of fee for service Medicare beneficiaries residing in one of 306 hospital referral regions in the United States in 2007 (n=5 153 877). Main outcome measures The effect of health risk adjustment on age, sex, and race adjusted mortality and spending rates among hospital referral regions using four indices: the standard Centers for Medicare and Medicaid Services—Hierarchical Condition Categories (HCC) index used by the US Medicare program (calculated from diagnoses listed in Medicare’s administrative database); a visit corrected HCC index (to reduce the effects of observational intensity on frequency of diagnoses); a poverty index (based on US census); and a population health index (calculated using data on incidence of hip fractures and strokes, and responses from a population based annual survey of health from the Centers for Disease Control and Prevention). Results Estimated variation in age, sex, and race adjusted mortality rates across hospital referral regions was reduced using the indices based on population health, poverty, and visit corrected HCC, but increased using the standard HCC index. Most of the residual variation in age, sex, and race adjusted mortality was explained (in terms of weighted R2) by the population health index: R2=0.65. The other indices explained less: R2=0.20 for the visit corrected HCC index; 0.19 for the poverty index, and 0.02 for the standard HCC index. The residual variation in age, sex, race, and price adjusted spending per capita across the 306 hospital referral regions explained by the indices (in terms of weighted R2) were 0.50 for

  4. Estimating Worker Risk Levels Using Accident/Incident Data

    SciTech Connect

    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.

  5. IMPROVED RISK ESTIMATES FOR CARBON TETRACHLORIDE

    SciTech Connect

    Benson, Janet M.; Springer, David L.

    1999-12-31

    Carbon tetrachloride has been used extensively within the DOE nuclear weapons facilities. Rocky Flats was formerly the largest volume consumer of CCl4 in the United States using 5000 gallons in 1977 alone (Ripple, 1992). At the Hanford site, several hundred thousand gallons of CCl4 were discharged between 1955 and 1973 into underground cribs for storage. Levels of CCl4 in groundwater at highly contaminated sites at the Hanford facility have exceeded 8 the drinking water standard of 5 ppb by several orders of magnitude (Illman, 1993). High levels of CCl4 at these facilities represent a potential health hazard for workers conducting cleanup operations and for surrounding communities. The level of CCl4 cleanup required at these sites and associated costs are driven by current human health risk estimates, which assume that CCl4 is a genotoxic carcinogen. The overall purpose of these studies was to improve the scientific basis for assessing the health risk associated with human exposure to CCl4. Specific research objectives of this project were to: (1) compare the rates of CCl4 metabolism by rats, mice and hamsters in vivo and extrapolate those rates to man based on parallel studies on the metabolism of CCl4 by rat, mouse, hamster and human hepatic microsomes in vitro; (2) using hepatic microsome preparations, determine the role of specific cytochrome P450 isoforms in CCl4-mediated toxicity and the effects of repeated inhalation and ingestion of CCl4 on these isoforms; and (3) evaluate the toxicokinetics of inhaled CCl4 in rats, mice and hamsters. This information has been used to improve the physiologically based pharmacokinetic (PBPK) model for CCl4 originally developed by Paustenbach et al. (1988) and more recently revised by Thrall and Kenny (1996). Another major objective of the project was to provide scientific evidence that CCl4, like chloroform, is a hepatocarcinogen only when exposure results in cell damage, cell killing and regenerative proliferation. In

  6. Cancer Risk Estimates from Space Flight Estimated Using Yields of Chromosome Damage in Astronaut's Blood Lymphocytes

    NASA Technical Reports Server (NTRS)

    George, Kerry A.; Rhone, J.; Chappell, L. J.; Cucinotta, F. A.

    2011-01-01

    To date, cytogenetic damage has been assessed in blood lymphocytes from more than 30 astronauts before and after they participated in long-duration space missions of three months or more on board the International Space Station. Chromosome damage was assessed using fluorescence in situ hybridization whole chromosome analysis techniques. For all individuals, the frequency of chromosome damage measured within a month of return from space was higher than their preflight yield, and biodosimetry estimates were within the range expected from physical dosimetry. Follow up analyses have been performed on most of the astronauts at intervals ranging from around 6 months to many years after flight, and the cytogenetic effects of repeat long-duration missions have so far been assessed in four individuals. Chromosomal aberrations in peripheral blood lymphocytes have been validated as biomarkers of cancer risk and cytogenetic damage can therefore be used to characterize excess health risk incurred by individual crewmembers after their respective missions. Traditional risk assessment models are based on epidemiological data obtained on Earth in cohorts exposed predominantly to acute doses of gamma-rays, and the extrapolation to the space environment is highly problematic, involving very large uncertainties. Cytogenetic damage could play a key role in reducing uncertainty in risk estimation because it is incurred directly in the space environment, using specimens from the astronauts themselves. Relative cancer risks were estimated from the biodosimetry data using the quantitative approach derived from the European Study Group on Cytogenetic Biomarkers and Health database. Astronauts were categorized into low, medium, or high tertiles according to their yield of chromosome damage. Age adjusted tertile rankings were used to estimate cancer risk and results were compared with values obtained using traditional modeling approaches. Individual tertile rankings increased after space

  7. A consistent local linear estimator of the covariate adjusted correlation coefficient

    PubMed Central

    Nguyen, Danh V.; Şentürk, Damla

    2009-01-01

    Consider the correlation between two random variables (X, Y), both not directly observed. One only observes X̃ = φ1(U)X + φ2(U) and Ỹ = ψ1(U)Y + ψ2(U), where all four functions {φl(·),ψl(·), l = 1, 2} are unknown/unspecified smooth functions of an observable covariate U. We consider consistent estimation of the correlation between the unobserved variables X and Y, adjusted for the above general dual additive and multiplicative effects of U, based on the observed data (X̃, Ỹ, U). PMID:21720454

  8. Continuing Bonds, Risk Factors for Complicated Grief, and Adjustment to Bereavement

    ERIC Educational Resources Information Center

    Field, Nigel P.; Filanosky, Charles

    2010-01-01

    This study examined type of continuing bonds (CB) expression in relation to risk factors for complicated grief and measures of bereavement-related adjustment. Externalized CB expressions involving illusions and hallucinations with the deceased were distinguished from internalized CB expressions involving use of the deceased as an autonomy…

  9. Measuring Profitability Impacts of Information Technology: Use of Risk Adjusted Measures.

    ERIC Educational Resources Information Center

    Singh, Anil; Harmon, Glynn

    2003-01-01

    Focuses on understanding how investments in information technology are reflected in the income statements and balance sheets of firms. Shows that the relationship between information technology investments and corporate profitability is much better explained by using risk-adjusted measures of corporate profitability than using the same measures…

  10. School Adjustment of Pupils with ADHD: Cognitive, Emotional and Temperament Risk Factors

    ERIC Educational Resources Information Center

    Sanchez-Perez, Noelia; Gonzalez-Salinas, Carmen

    2013-01-01

    From different research perspectives, the cognitive and emotional characteristics associated with ADHD in children have been identified as risk factors for the development of diverse adjustment problems in the school context. Research in nonclinical population can additionally help in understanding ADHD deficits, since children with specific…

  11. Comparison of the Properties of Regression and Categorical Risk-Adjustment Models

    PubMed Central

    Averill, Richard F.; Muldoon, John H.; Hughes, John S.

    2016-01-01

    Clinical risk-adjustment, the ability to standardize the comparison of individuals with different health needs, is based upon 2 main alternative approaches: regression models and clinical categorical models. In this article, we examine the impact of the differences in the way these models are constructed on end user applications. PMID:26945302

  12. 48 CFR 215.404-71-3 - Contract type risk and working capital adjustment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Contract type risk and working capital adjustment. 215.404-71-3 Section 215.404-71-3 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing...

  13. Assessing At-Risk Youth Using the Reynolds Adolescent Adjustment Screening Inventory with a Latino Population

    ERIC Educational Resources Information Center

    Balkin, Richard S.; Cavazos, Javier, Jr.; Hernandez, Arthur E.; Garcia, Roberto; Dominguez, Denise L.; Valarezo, Alexandra

    2013-01-01

    Factor analyses were conducted on scores from the Reynolds Adolescent Adjustment Screening Inventory (RAASI; Reynolds, 2001) representing at-risk Latino youth. The 4-factor model of the RAASI did not exhibit a good fit. However, evidence of generalizability for Latino youth was noted. (Contains 3 tables.)

  14. Risk adjustment of Medicare capitation payments using the CMS-HCC model.

    PubMed

    Pope, Gregory C; Kautter, John; Ellis, Randall P; Ash, Arlene S; Ayanian, John Z; Lezzoni, Lisa I; Ingber, Melvin J; Levy, Jesse M; Robst, John

    2004-01-01

    This article describes the CMS hierarchical condition categories (HCC) model implemented in 2004 to adjust Medicare capitation payments to private health care plans for the health expenditure risk of their enrollees. We explain the model's principles, elements, organization, calibration, and performance. Modifications to reduce plan data reporting burden and adaptations for disabled, institutionalized, newly enrolled, and secondary payer subpopulations are discussed. PMID:15493448

  15. Global Burden of Leptospirosis: Estimated in Terms of Disability Adjusted Life Years

    PubMed Central

    Torgerson, Paul R.; Hagan, José E.; Costa, Federico; Calcagno, Juan; Kane, Michael; Martinez-Silveira, Martha S.; Goris, Marga G. A.; Stein, Claudia; Ko, Albert I.; Abela-Ridder, Bernadette

    2015-01-01

    Background Leptospirosis, a spirochaetal zoonosis, occurs in diverse epidemiological settings and affects vulnerable populations, such as rural subsistence farmers and urban slum dwellers. Although leptospirosis can cause life-threatening disease, there is no global burden of disease estimate in terms of Disability Adjusted Life Years (DALYs) available. Methodology/Principal Findings We utilised the results of a parallel publication that reported global estimates of morbidity and mortality due to leptospirosis. We estimated Years of Life Lost (YLLs) from age and gender stratified mortality rates. Years of Life with Disability (YLDs) were developed from a simple disease model indicating likely sequelae. DALYs were estimated from the sum of YLLs and YLDs. The study suggested that globally approximately 2·90 million DALYs are lost per annum (UIs 1·25–4·54 million) from the approximately annual 1·03 million cases reported previously. Males are predominantly affected with an estimated 2·33 million DALYs (UIs 0·98–3·69) or approximately 80% of the total burden. For comparison, this is over 70% of the global burden of cholera estimated by GBD 2010. Tropical regions of South and South-east Asia, Western Pacific, Central and South America, and Africa had the highest estimated leptospirosis disease burden. Conclusions/Significance Leptospirosis imparts a significant health burden worldwide, which approach or exceed those encountered for a number of other zoonotic and neglected tropical diseases. The study findings indicate that highest burden estimates occur in resource-poor tropical countries, which include regions of Africa where the burden of leptospirosis has been under-appreciated and possibly misallocated to other febrile illnesses such as malaria. PMID:26431366

  16. Estimating adjusted prevalence ratio in clustered cross-sectional epidemiological data

    PubMed Central

    Santos, Carlos Antônio ST; Fiaccone, Rosemeire L; Oliveira, Nelson F; Cunha, Sérgio; Barreto, Maurício L; do Carmo, Maria Beatriz B; Moncayo, Ana-Lucia; Rodrigues, Laura C; Cooper, Philip J; Amorim, Leila D

    2008-01-01

    Background Many epidemiologic studies report the odds ratio as a measure of association for cross-sectional studies with common outcomes. In such cases, the prevalence ratios may not be inferred from the estimated odds ratios. This paper overviews the most commonly used procedures to obtain adjusted prevalence ratios and extends the discussion to the analysis of clustered cross-sectional studies. Methods Prevalence ratios(PR) were estimated using logistic models with random effects. Their 95% confidence intervals were obtained using delta method and clustered bootstrap. The performance of these approaches was evaluated through simulation studies. Using data from two studies with health-related outcomes in children, we discuss the interpretation of the measures of association and their implications. Results The results from data analysis highlighted major differences between estimated OR and PR. Results from simulation studies indicate an improved performance of delta method compared to bootstrap when there are small number of clusters. Conclusion We recommend the use of logistic model with random effects for analysis of clustered data. The choice of method to estimate confidence intervals for PR (delta or bootstrap method) should be based on study design. PMID:19087281

  17. A VLBI baseline post-adjustment approach for station velocity estimation in Eurasian continent

    NASA Astrophysics Data System (ADS)

    Zhang, Zhibin; Liu, Xiang

    2014-10-01

    Baseline lengths and their time-derivatives among 58 geodetic VLBI stations were fitted by using 4439 observing sessions from the International VLBI Service for Geodesy and Astrometry (IVS). First, the velocities of eight stations in Eurasian continent were set as unknown quantities. Then, two standard global solutions from 3523 IVS sessions and 1110 sessions from database code XA, respectively, were applied prior to all-station coordinates and the non-estimated station velocities. Finally, from the relations among the coordinates, velocities, baseline length and its time-derivative, two types of baseline post-adjustment (BPA) were used to estimate the velocities of the eight stations. We discuss the data processing details, including the effect of different prior values for the stations and the optimal solution. The results suggest that the precision of the station velocities based on the proposed approach is comparable to that of the global solution of the XA sessions. The baseline structure and the prior values of the stations affect the velocity estimates. Compared to the standard method of velocity estimation, there are no external constrains and conditions used in the proposed method.

  18. Uncertainty of Calculated Risk Estimates for Secondary Malignancies After Radiotherapy

    SciTech Connect

    Kry, Stephen F. . E-mail: sfkry@mdanderson.org; Followill, David; White, R. Allen; Stovall, Marilyn; Kuban, Deborah A.; Salehpour, Mohammad

    2007-07-15

    Purpose: The significance of risk estimates for fatal secondary malignancies caused by out-of-field radiation exposure remains unresolved because the uncertainty in calculated risk estimates has not been established. This work examines the uncertainty in absolute risk estimates and in the ratio of risk estimates between different treatment modalities. Methods and Materials: Clinically reasonable out-of-field doses and calculated risk estimates were taken from the literature for several prostate treatment modalities, including intensity-modulated radiotherapy (IMRT), and were recalculated using the most recent risk model. The uncertainties in this risk model and uncertainties in the linearity of the dose-response model were considered in generating 90% confidence intervals for the uncertainty in the absolute risk estimates and in the ratio of the risk estimates. Results: The absolute risk estimates of fatal secondary malignancy were associated with very large uncertainties, which precluded distinctions between the risks associated with the different treatment modalities considered. However, a much smaller confidence interval exists for the ratio of risk estimates, and this ratio between different treatment modalities may be statistically significant when there is an effective dose equivalent difference of at least 50%. Such a difference may exist between clinically reasonable treatment options, including 6-MV IMRT versus 18-MV IMRT for prostate therapy. Conclusion: The ratio of the risk between different treatment modalities may be significantly different. Consequently risk models and associated risk estimates may be useful and meaningful for evaluating different treatment options. The calculated risk of secondary malignancy should be considered in the selection of an optimal treatment plan.

  19. Tidally Adjusted Estimates of Susceptibility to Sea Level Rise for the Contiguous U.S

    NASA Astrophysics Data System (ADS)

    Strauss, B.; Ziemlinski, R.; Weiss, J. L.; Overpeck, J. T.

    2011-12-01

    As projections for sea level rise this century increase to 1 m or more, it is becoming increasingly important to understand what communities and assets may be most at risk. Here we present the first analysis of low-lying coastal land, housing and population covering the contiguous U.S. while accounting for local and regional differences in the elevation of mean high tides, which range from ~0-3 m above mean sea level. Previous work at this scale has implicitly equated land elevation with height relative to local high tides, leading to underestimated risk in areas with high-elevation high tides, and compromising comparisons of risk across regions with different tidal levels. Our refinement substantially increases the national estimate of land and population within 1-6 m of high tide; we also rank cities and states by their topographic susceptibility to sea level rise.

  20. Adjusting for car occupant injury liability in relation to age, speed limit, and gender-specific driver crash involvement risk.

    PubMed

    Keall, Michael; Frith, William

    2004-12-01

    It is well established that older drivers' fragility is an important factor associated with higher levels of fatal crash involvement for older drivers. There has been less research on age-related fragility with respect to the sort of minor injuries that are more common in injury crashes. This study estimates a quantity that is related to injury fragility: the probability that a driver or a passenger of that driver will be injured in crashes involving two cars. The effects of other factors apart from drivers' fragility are included in this measure, including the fragility of the passengers, the crashworthiness of cars driven, seatbelt use by the occupants, and characteristics of crashes (including configuration and impact speed). The car occupant injury liability estimates appropriately includes these factors to adjust risk curves by age, gender, and speed limit accounting for overrepresentation in crashes associated with fragility and these other factors. PMID:15545071

  1. Risk-adjusted antibiotic consumption in 34 public acute hospitals in Ireland, 2006 to 2014.

    PubMed

    Oza, Ajay; Donohue, Fionnuala; Johnson, Howard; Cunney, Robert

    2016-08-11

    As antibiotic consumption rates between hospitals can vary depending on the characteristics of the patients treated, risk-adjustment that compensates for the patient-based variation is required to assess the impact of any stewardship measures. The aim of this study was to investigate the usefulness of patient-based administrative data variables for adjusting aggregate hospital antibiotic consumption rates. Data on total inpatient antibiotics and six broad subclasses were sourced from 34 acute hospitals from 2006 to 2014. Aggregate annual patient administration data were divided into explanatory variables, including major diagnostic categories, for each hospital. Multivariable regression models were used to identify factors affecting antibiotic consumption. Coefficient of variation of the root mean squared errors (CV-RMSE) for the total antibiotic usage model was very good (11%), however, the value for two of the models was poor (> 30%). The overall inpatient antibiotic consumption increased from 82.5 defined daily doses (DDD)/100 bed-days used in 2006 to 89.2 DDD/100 bed-days used in 2014; the increase was not significant after risk-adjustment. During the same period, consumption of carbapenems increased significantly, while usage of fluoroquinolones decreased. In conclusion, patient-based administrative data variables are useful for adjusting hospital antibiotic consumption rates, although additional variables should also be employed. PMID:27541730

  2. Indoor Ultra-Wide Band Network Adjustment using Maximum Likelihood Estimation

    NASA Astrophysics Data System (ADS)

    Koppanyi, Z.; Toth, C. K.

    2014-11-01

    This study is the part of our ongoing research on using ultra-wide band (UWB) technology for navigation at the Ohio State University. Our tests have indicated that the UWB two-way time-of-flight ranges under indoor circumstances follow a Gaussian mixture distribution that may be caused by the incompleteness of the functional model. In this case, to adjust the UWB network from the observed ranges, the maximum likelihood estimation (MLE) may provide a better solution for the node coordinates than the widely-used least squares approach. The prerequisite of the maximum likelihood method is to know the probability density functions. The 30 Hz sampling rate of the UWB sensors enables to estimate these functions between each node from the samples in static positioning mode. In order to prove the MLE hypothesis, an UWB network has been established in a multi-path density environment for test data acquisition. The least squares and maximum likelihood coordinate solutions are determined and compared, and the results indicate that better accuracy can be achieved with maximum likelihood estimation.

  3. MM-Estimator and Adjusted Super Smoother based Simultaneous Prediction Confedenc

    2002-07-19

    A Novel Application of Regression Analysis (MM-Estimator) with Simultaneous Prediction Confidence Intervals are proposed to detect up- or down-regulated genes, which are outliers in scatter plots based on log-transformed red (Cy5 fluorescent dye) versus green (Cy3 fluorescent Dye) intensities. Advantages of the application: 1) Robust and Resistant MM-Estimator is a Reliable Method to Build Linear Regression In the presence of Outliers, 2) Exploratory Data Analysis Tools (Boxplots, Averaged Shifted Histograms, Quantile-Quantile Normal Plots and Scattermore » Plots) are Unsed to Test Visually underlying assumptions of linearity and Contaminated Normality in Microarray data), 3) Simultaneous prediction confidence intervals (SPCIs) Guarantee a desired confidence level across the whole range of the data points used for the scatter plots. Results of the outlier detection procedure is a set of significantly differentially expressed genes extracted from the employed microarray data set. A scatter plot smoother (super smoother or locally weighted regression) is used to quantify heteroscendasticity is residual variance (Commonly takes place in lower and higher intensity areas). The set of differentially expressed genes is quantified using interval estimates for P-values as a probabilistic measure of being outlier by chance. Monte Carlo simultations are used to adjust super smoother-based SPCIs.her.« less

  4. Approaches to risk-adjusting outcome measures applied to criminal justice involvement after community service.

    PubMed

    Banks, S M; Pandiani, J A; Bramley, J

    2001-08-01

    The ethic of fairness in program evaluation requires that measures of behavioral health agency performance be sensitive to differences in those agencies' caseload composition. The authors describe two traditional approaches to the statistical risk adjustment of outcome measures (stratification weighting and pre-post measurement) that are designed to account for differences in caseload composition and introduce a method that incorporates the strengths of both approaches. Procedures for deriving each of these measures are described in detail and demonstrated in the evaluation of a statewide system of community-based behavioral health care programs. This evaluation examines the degree to which service recipients get into trouble with the law after treatment. Three measures are recommended for inclusion in outcome-oriented "report cards," and the interpretation of each measure is discussed. Finally, the authors suggest formats for graphic and tabular presentation of the risk-adjusted evaluation for sharing findings with diverse stakeholder groups. PMID:11497020

  5. Evolving Adjustments to External (Gamma) Slope Factors for CERCLA Risk and Dose Assessments - 12290

    SciTech Connect

    Walker, Stuart

    2012-07-01

    To model the external exposure pathway in risk and dose assessments of radioactive contamination at Superfund sites, the U.S. Environmental Protection Agency (EPA) uses slope factors (SFs), also known as risk coefficients, and dose conversion factors (DCFs). Without any adjustment these external radiation exposure pathways effectively assumes that an individual is exposed to a source geometry that is effectively an infinite slab. The concept of an 'infinite slab' means that the thickness of the contaminated zone and its aerial extent are so large that it behaves as if it were infinite in its physical dimensions. EPA has been making increasingly complex adjustments to account for the extent of the contamination and its corresponding radiation field to provide more accurate risk and dose assessment modeling when using its calculators. In most instances, the more accurate modeling results derived from these gamma adjustments are less conservative. The notable exception are for some radionuclides in rooms with contaminated walls, ceiling, and floors, and the receptor is in location of the room with the highest amount of radiation exposure, usually the corner of small rooms and the center of large conference rooms. (authors)

  6. The over-estimation of risk in pregnancy.

    PubMed

    Robinson, Monique; Pennell, Craig E; McLean, Neil J; Oddy, Wendy H; Newnham, John P

    2011-06-01

    The concept of risk is especially salient to obstetric care. Unknown factors can still be responsible for peri-natal morbidity and mortality in circumstances that appeared to present little risk, while perfectly healthy infants are born in high-risk circumstances: a contradiction that patients and providers struggle with on a daily basis. With such contradictions comes the potential for the over-estimation of risk during pregnancy in order to assure a positive outcome. Understanding and addressing the estimation of risk during pregnancy requires acknowledging the history of obstetric risk in addition to understanding risk-related psychological theory. A relationship of trust between provider and patient is vital in addressing risk over-estimation, as is encouraging the development of self-efficacy in patients. Ultimately obstetric care is complex and efforts to avoid pre-natal risk exposure based on heightened perceptions of threat may do more harm than the perceived threat itself. PMID:21480770

  7. A risk-adjusted approach to comparing the return on investment in health care programs.

    PubMed

    Sendi, Pedram; Al, Maiwenn J; Zimmermann, Heinz

    2004-09-01

    The league table approach to rank ordering health care programs according to the incremental cost-effectiveness ratio is a common method to guide policy makers in setting priorities for resource allocation. In the presence of uncertainty, however, ranking programs is complicated by the degree of variability associated with each program. Confidence intervals for cost-effectiveness ratios may be overlapping. Moreover, confidence intervals may include negative ratios and the interpretation of negative cost-effectiveness ratios is ambiguous. We suggest to rank mutually exclusive health care programs according to their rate of return which is defined as the net monetary benefit over the costs of the program. However, how does a program with a higher expected return but higher uncertainty compare to a program with a lower expected return but lower risk? In the present paper we propose a risk-adjusted measure to compare the return on investment in health care programs. Financing a health care program is treated as an investment in a risky asset. The risky asset is combined with a risk-free asset in order to construct a combined portfolio. The weights attributed to the risk-free and risky assets are chosen in such a manner that all programs under consideration exhibit the same degree of uncertainty. We can then compare the performance of the individual programs by constructing a risk-adjusted league table of expected returns. PMID:15277778

  8. The public health hazards of risk avoidance associated with public reporting of risk adjusted outcomes in coronary intervention

    PubMed Central

    Resnic, Frederic S.; Welt, Frederick G. P.

    2009-01-01

    Public reporting of risk adjusted outcomes for percutaneous coronary interventional (PCI) procedures has been mandated in New York State for more than a decade. Over that time there has been a significant decline in the unadjusted mortality following such procedures. Massachusetts joined New York in 2003 as only the second state to require case level reporting of every coronary interventional procedure performed. In this review, we explore the differences in the populations reported by the two states, and consider possible risks of public reporting of clinical outcomes following PCI procedures including the risk of increasing conservatism in the treatment of the sickest patients. We offer a conceptual framework to understand the potential risk-averse behavior of interventional cardiologists subject to public reporting, and offer several proposals to counteract this potential deleterious effect of reporting programs. PMID:19264236

  9. Estimating contribution of anthocyanin pigments to osmotic adjustment during winter leaf reddening.

    PubMed

    Hughes, Nicole M; Carpenter, Kaylyn L; Cannon, Jonathan G

    2013-01-15

    The association between plant water stress and synthesis of red, anthocyanin pigments in leaves has led some plant biologists to propose an osmotic function of leaf reddening. According to this hypothesis, anthocyanins function as a solute in osmotic adjustment (OA), contributing to depression of osmotic potential (Ψ(π)) and maintenance of turgor pressure during drought-stressed conditions. Here we calculate the percent contribution of anthocyanin to leaf Ψ(π) during OA in two angiosperm evergreen species, Galax urceolata and Gaultheria procumbens. Both species exhibit dramatic leaf reddening under high light during winter, concomitant with declines in leaf water potential and accumulation of solutes. Data previously published by the authors on osmotic potential at full turgor (Ψ(π,100)) of G. urceolata and G. procumbens leaves before and after leaf reddening were used to estimate OA. In vivo molar concentrations of anthocyanin, glucose, fructose, and sucrose measured from the same individuals were converted to pressure equivalents using the Ideal Gas Law, and percent contribution to OA was estimated. Estimated mean OA during winter was -0.7MPa for G. urceolata and -0.8MPa for G. procumbens. In vivo concentrations of anthocyanin (3-10mM) were estimated to account for ∼2% of OA during winter, and comprised <0.7% of Ψ(π,100) in both species. Glucose, fructose, and sucrose combined accounted for roughly 50 and 80% of OA for G. urceolata and G. procumbens, respectively, and comprised ∼20% of Ψ(π,100). We observed that a co-occurring, acyanic species (Vinca minor) achieved similar OA without synthesizing anthocyanin. We conclude that anthocyanins represent a measurable, albeit meager, component of OA in red-leafed evergreen species during winter. However, due to their low concentrations, metabolic costliness relative to other osmolytes, and striking red color (unnecessary for an osmotic function), it is unlikely that they are synthesized solely for an

  10. Estimated radiation risks associated with endodontic radiography.

    PubMed

    Danforth, R A; Torabinejad, M

    1990-02-01

    Endodontic patients are sometimes concerned about the risks of tumors or cataracts from radiation exposure during root canal therapy. By using established dose and risk information, we calculated the extent of these risks. The chance of getting leukemia from an endodontic x-ray survey using 90 kVp was found to be 1 in 7.69 million, the same as the risk of dying from cancer from smoking 0.94 cigarettes or from an auto accident when driving 3.7 km. Risk of thyroid gland neoplasia was 1 in 667,000 (smoking 11.6 cigarettes, driving 45 km) and risk of salivary gland neoplasia 1 in 1.35 million (smoking 5.4 cigarettes, driving 21.1 km). Use of 70 kVp radiography reduced these risks only slightly. To receive the threshold dose to eyes to produce cataract changes, a patient would have to undergo 10,900 endodontic surveys. PMID:2390963

  11. NDVI saturation adjustment: a new approach for improving cropland performance estimates in the Greater Platte River Basin, USA

    USGS Publications Warehouse

    Gu, Yingxin; Wylie, Bruce K.; Howard, Daniel M.; Phuyal, Khem P.; Ji, Lei

    2013-01-01

    In this study, we developed a new approach that adjusted normalized difference vegetation index (NDVI) pixel values that were near saturation to better characterize the cropland performance (CP) in the Greater Platte River Basin (GPRB), USA. The relationship between NDVI and the ratio vegetation index (RVI) at high NDVI values was investigated, and an empirical equation for estimating saturation-adjusted NDVI (NDVIsat_adjust) based on RVI was developed. A 10-year (2000–2009) NDVIsat_adjust data set was developed using 250-m 7-day composite historical eMODIS (expedited Moderate Resolution Imaging Spectroradiometer) NDVI data. The growing season averaged NDVI (GSN), which is a proxy for ecosystem performance, was estimated and long-term NDVI non-saturation- and saturation-adjusted cropland performance (CPnon_sat_adjust, CPsat_adjust) maps were produced over the GPRB. The final CP maps were validated using National Agricultural Statistics Service (NASS) crop yield data. The relationship between CPsat_adjust and the NASS average corn yield data (r = 0.78, 113 samples) is stronger than the relationship between CPnon_sat_adjust and the NASS average corn yield data (r = 0.67, 113 samples), indicating that the new CPsat_adjust map reduces the NDVI saturation effects and is in good agreement with the corn yield ground observations. Results demonstrate that the NDVI saturation adjustment approach improves the quality of the original GSN map and better depicts the actual vegetation conditions of the GPRB cropland systems.

  12. Adjusting HIV prevalence estimates for non-participation: an application to demographic surveillance

    PubMed Central

    McGovern, Mark E.; Marra, Giampiero; Radice, Rosalba; Canning, David; Newell, Marie-Louise; Bärnighausen, Till

    2015-01-01

    Introduction HIV testing is a cornerstone of efforts to combat the HIV epidemic, and testing conducted as part of surveillance provides invaluable data on the spread of infection and the effectiveness of campaigns to reduce the transmission of HIV. However, participation in HIV testing can be low, and if respondents systematically select not to be tested because they know or suspect they are HIV positive (and fear disclosure), standard approaches to deal with missing data will fail to remove selection bias. We implemented Heckman-type selection models, which can be used to adjust for missing data that are not missing at random, and established the extent of selection bias in a population-based HIV survey in an HIV hyperendemic community in rural South Africa. Methods We used data from a population-based HIV survey carried out in 2009 in rural KwaZulu-Natal, South Africa. In this survey, 5565 women (35%) and 2567 men (27%) provided blood for an HIV test. We accounted for missing data using interviewer identity as a selection variable which predicted consent to HIV testing but was unlikely to be independently associated with HIV status. Our approach involved using this selection variable to examine the HIV status of residents who would ordinarily refuse to test, except that they were allocated a persuasive interviewer. Our copula model allows for flexibility when modelling the dependence structure between HIV survey participation and HIV status. Results For women, our selection model generated an HIV prevalence estimate of 33% (95% CI 27–40) for all people eligible to consent to HIV testing in the survey. This estimate is higher than the estimate of 24% generated when only information from respondents who participated in testing is used in the analysis, and the estimate of 27% when imputation analysis is used to predict missing data on HIV status. For men, we found an HIV prevalence of 25% (95% CI 15–35) using the selection model, compared to 16% among those who

  13. Relating space radiation environments to risk estimates

    SciTech Connect

    Curtis, S.B.

    1991-10-01

    This lecture will provide a bridge from the physical energy or LET spectra as might be calculated in an organ to the risk of carcinogenesis, a particular concern for extended missions to the moon or beyond to Mars. Topics covered will include (1) LET spectra expected from galactic cosmic rays, (2) probabilities that individual cell nuclei in the body will be hit by heavy galactic cosmic ray particles, (3) the conventional methods of calculating risks from a mixed environment of high and low LET radiation, (4) an alternate method which provides certain advantages using fluence-related risk coefficients (risk cross sections), and (5) directions for future research and development of these ideas.

  14. Development and Validation of a Risk-Adjustment Tool in Acute Asthma

    PubMed Central

    Tsai, Chu-Lin; Clark, Sunday; Sullivan, Ashley F; Camargo, Carlos A

    2009-01-01

    Objective To develop and prospectively validate a risk-adjustment tool in acute asthma. Data Sources Data were obtained from two large studies on acute asthma, the Multicenter Airway Research Collaboration (MARC) and the National Emergency Department Safety Study (NEDSS) cohorts. Both studies involved >60 emergency departments (EDs) and were performed during 1996–2001 and 2003–2006, respectively. Both included patients aged 18–54 years presenting to the ED with acute asthma. Study Design Retrospective cohort studies. Data Collection Clinical information was obtained from medical record review. The risk index was derived in the MARC cohort and then was prospectively validated in the NEDSS cohort. Principle Findings There were 3,515 patients in the derivation cohort and 3,986 in the validation cohort. The risk index included nine variables (age, sex, current smoker, ever admitted for asthma, ever intubated for asthma, duration of symptoms, respiratory rate, peak expiratory flow, and number of beta-agonist treatments) and showed satisfactory discrimination (area under the receiver operating characteristic curve, 0.75) and calibration (p=.30 for Hosmer–Lemeshow test) when applied to the validation cohort. Conclusions We developed and validated a novel risk-adjustment tool in acute asthma. This tool can be used for health care provider profiling to identify outliers for quality improvement purposes. PMID:19619246

  15. Tidally adjusted estimates of topographic vulnerability to sea level rise and flooding for the contiguous United States

    NASA Astrophysics Data System (ADS)

    Strauss, Benjamin H.; Ziemlinski, Remik; Weiss, Jeremy L.; Overpeck, Jonathan T.

    2012-03-01

    Because sea level could rise 1 m or more during the next century, it is important to understand what land, communities and assets may be most at risk from increased flooding and eventual submersion. Employing a recent high-resolution edition of the National Elevation Dataset and using VDatum, a newly available tidal model covering the contiguous US, together with data from the 2010 Census, we quantify low-lying coastal land, housing and population relative to local mean high tide levels, which range from ˜0 to 3 m in elevation (North American Vertical Datum of 1988). Previous work at regional to national scales has sometimes equated elevation with the amount of sea level rise, leading to underestimated risk anywhere where the mean high tide elevation exceeds 0 m, and compromising comparisons across regions with different tidal levels. Using our tidally adjusted approach, we estimate the contiguous US population living on land within 1 m of high tide to be 3.7 million. In 544 municipalities and 38 counties, we find that over 10% of the population lives below this line; all told, some 2150 towns and cities have some degree of exposure. At the state level, Florida, Louisiana, California, New York and New Jersey have the largest sub-meter populations. We assess topographic susceptibility of land, housing and population to sea level rise for all coastal states, counties and municipalities, from 0 to 6 m above mean high tide, and find important threat levels for widely distributed communities of every size. We estimate that over 22.9 million Americans live on land within 6 m of local mean high tide.

  16. Monte Carlo estimation of the dose and heating of cobalt adjuster rods irradiated in the CANDU 6 reactor core.

    PubMed

    Gugiu, Daniela; Dumitrache, Ion

    2005-01-01

    The present work is a part of a more complex project related to the replacement of the original stainless steel adjuster rods with cobalt assemblies in the CANDU 6 reactor core. The 60Co produced by 59Co irradiation could be used extensively in medicine and industry. The paper will mainly describe some of the reactor physics and safety requirements that must be carried into practice for the Co adjuster rods. The computations related to the neutronic equivalence of the stainless steel adjusters with the Co adjuster assemblies, as well as the estimations of the activity and heating of the irradiated cobalt rods, are performed using the Monte Carlo codes MCNP5 and MONTEBURNS 2.1. The activity values are used to evaluate the dose at the surface of the device designed to transport the cobalt adjusters. PMID:16604599

  17. Propensity score methods for estimating relative risks in cluster randomized trials with low-incidence binary outcomes and selection bias.

    PubMed

    Leyrat, Clémence; Caille, Agnès; Donner, Allan; Giraudeau, Bruno

    2014-09-10

    Despite randomization, selection bias may occur in cluster randomized trials. Classical multivariable regression usually allows for adjusting treatment effect estimates with unbalanced covariates. However, for binary outcomes with low incidence, such a method may fail because of separation problems. This simulation study focused on the performance of propensity score (PS)-based methods to estimate relative risks from cluster randomized trials with binary outcomes with low incidence. The results suggested that among the different approaches used (multivariable regression, direct adjustment on PS, inverse weighting on PS, and stratification on PS), only direct adjustment on the PS fully corrected the bias and moreover had the best statistical properties. PMID:24771662

  18. Variation In Accountable Care Organization Spending And Sensitivity To Risk Adjustment: Implications For Benchmarking.

    PubMed

    Rose, Sherri; Zaslavsky, Alan M; McWilliams, J Michael

    2016-03-01

    Spending targets (or benchmarks) for accountable care organizations (ACOs) participating in the Medicare Shared Savings Program must be set carefully to encourage program participation while achieving fiscal goals and minimizing unintended consequences, such as penalizing ACOs for serving sicker patients. Recently proposed regulatory changes include measures to make benchmarks more similar for ACOs in the same area with different historical spending levels. We found that ACOs vary widely in how their spending levels compare with those of other local providers after standard case-mix adjustments. Additionally adjusting for survey measures of patient health meaningfully reduced the variation in differences between ACO spending and local average fee-for-service spending, but substantial variation remained, which suggests that differences in care efficiency between ACOs and local non-ACO providers vary widely. Accordingly, measures to equilibrate benchmarks between high- and low-spending ACOs--such as setting benchmarks to risk-adjusted average fee-for-service spending in an area--should be implemented gradually to maintain participation by ACOs with high spending. Use of survey information also could help mitigate perverse incentives for risk selection and upcoding and limit unintended consequences of new benchmarking methodologies for ACOs serving sicker patients. PMID:26953298

  19. Comparative coronary risks of apixaban, rivaroxaban and dabigatran: a meta-analysis and adjusted indirect comparison

    PubMed Central

    Loke, Yoon K; Pradhan, Shiva; Yeong, Jessica Ka-yan; Kwok, Chun Shing

    2014-01-01

    Aims There are concerns regarding increased risk of acute coronary syndrome with dabigatran. We aimed to assess whether alternative treatment options such as rivaroxaban or apixaban carry a similar risk as compared with dabigatran. Methods We searched MEDLINE and EMBASE for randomized controlled trials of apixaban, dabigatran or rivaroxaban against control (placebo, heparin or vitamin K antagonist). We pooled odds ratios (OR) for adverse coronary events (acute coronary syndrome or myocardial infarction) using fixed effect meta-analysis and assessed heterogeneity with I2. We conducted adjusted indirect comparisons to compare risk of adverse coronary events with apixaban or rivaroxaban vs. dabigatran. Results Twenty-seven randomized controlled trials met the inclusion criteria. Dabigatran was associated with a significantly increased risk of adverse coronary events in pooled analysis of nine trials (OR 1.45, 95% CI 1.14, 1.86). There was no signal for coronary risk with apixaban from nine trials (pooled OR 0.89, 95% CI 0.78, 1.03) or rivaroxaban from nine trials (pooled OR 0.81, 95% CI 0.72, 0.93). Overall, adjusted indirect comparison suggested that both apixaban (OR 0.61, 95% CI 0.44, 0.85) and rivaroxaban (OR 0.54; 95% CI 0.39, 0.76) were associated with lower coronary risk than dabigatran. Restricting the indirect comparison to a vitamin K antagonist as a common control, yielded similar findings, OR 0.57 (95% CI 0.39, 0.85) for apixaban vs. dabigatran and 0.53 (95% CI 0.37, 0.77) for rivaroxaban vs. dabigatran. Conclusions There are significant differences in the comparative safety of apixaban, rivaroxaban and dabigatran with regards to acute coronary adverse events. PMID:24617578

  20. Effect of Risk Adjustment Method on Comparisons of Health Care Utilization Between Complementary and Alternative Medicine Users and Nonusers

    PubMed Central

    Gerkovich, Mary M.; Cherkin, Daniel C.; Deyo, Richard A.; Sherman, Karen J.; Lafferty, William E.

    2013-01-01

    Abstract Objectives Complementary and alternative medicine (CAM) providers are becoming more integrated into the United States health care system. Because patients self-select CAM use, risk adjustment is needed to make the groups more comparable when analyzing utilization. This study examined how the choice of risk adjustment method affects assessment of CAM use on overall health care utilization. Design and subjects Insurance claims data for 2000–2003 from Washington State, which mandates coverage of CAM providers, were analyzed. Three (3) risk adjustment methods were compared in patients with musculoskeletal conditions: Adjusted Clinical Groups (ACG), Diagnostic Cost Groups (DCG), and the Charlson Index. Relative Value Units (RVUs) were used as a proxy for expenditures. Two (2) sets of median regression models were created: prospective, which used risk adjustments from the previous year to predict RVU in the subsequent year, and concurrent, which used risk adjustment measures to predict RVU in the same year. Results The sample included 92,474 claimants. Prospective models showed little difference in the effect of CAM use on RVU among the three risk adjustment methods, and all models had low predictive power (R2 ≤0.05). In the concurrent models, coefficients were similar in direction and magnitude for all risk adjustment methods, but in some models the predicted effect of CAM use on RVU differed by as much as double between methods. Results of DCG and ACG models were similar and were stronger than Charlson models. Conclusions Choice of risk adjustment method may have a modest effect on the outcome of interest. PMID:23036140

  1. Preoperative Evaluation: Estimation of Pulmonary Risk.

    PubMed

    Lakshminarasimhachar, Anand; Smetana, Gerald W

    2016-03-01

    Postoperative pulmonary complications (PPCs) are common after major non-thoracic surgery and associated with significant morbidity and high cost of care. A number of risk factors are strong predictors of PPCs. The overall goal of the preoperative pulmonary evaluation is to identify these potential, patient and procedure-related risks and optimize the health of the patients before surgery. A thorough clinical examination supported by appropriate laboratory tests will help guide the clinician to provide optimal perioperative care. PMID:26927740

  2. 12 CFR Appendix B to Part 3 - Risk-Based Capital Guidelines; Market Risk Adjustment

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the Board's Regulation EE (12 CFR part 231); or (2) If the transaction does not meet the criteria set... daily management process. (3) The bank's policies and procedures must identify, and the bank must... across risk categories, provided that the bank's process for measuring correlations is sound. In...

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

    PubMed

    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). PMID:23195792

  4. Vigilance adjustments in relation to long- and short term risk in wild fallow deer (Dama dama).

    PubMed

    Bergvall, Ulrika A; Svensson, Lisa; Kjellander, Petter

    2016-07-01

    The risk allocation hypothesis predicts that vigilance should be adjusted to the temporal variation in risk. We test this hypothesis in wild fallow deer exposed to short term (disturbance) and long term (presence of a fawn after parturition) changes in risk. We recorded the proportion, frequency and type of vigilance and size of used area before and after parturition, in GPS-collared wild female fallow deer. Vigilance was divided in two main groups: "non-grazing vigilance" and "grazing vigilance". The latter group was divided into "grazing vigilance while chewing" and a "grazing vigilance when chewing was interrupted". By recording external disturbance in form of passing cars, we were able to investigate if this altered the amount, and type of vigilance. We found that females increased the proportion and frequency of "grazing vigilance stop chewing" after parturition. The "grazing vigilance chewing" was unaffected, but "non-grazing vigilance" decreased. Disturbance increased the proportion "grazing vigilance stop chewing" to the same extent before and after parturition. We found a clear decrease in female home range size after parturition as a possible behavioural adjustment. The increase in "grazing vigilance stop chewing" after parturition is a rarely described but expected cost of reproduction. PMID:27094230

  5. Covariate adjustment of cumulative incidence functions for competing risks data using inverse probability of treatment weighting.

    PubMed

    Neumann, Anke; Billionnet, Cécile

    2016-06-01

    In observational studies without random assignment of the treatment, the unadjusted comparison between treatment groups may be misleading due to confounding. One method to adjust for measured confounders is inverse probability of treatment weighting. This method can also be used in the analysis of time to event data with competing risks. Competing risks arise if for some individuals the event of interest is precluded by a different type of event occurring before, or if only the earliest of several times to event, corresponding to different event types, is observed or is of interest. In the presence of competing risks, time to event data are often characterized by cumulative incidence functions, one for each event type of interest. We describe the use of inverse probability of treatment weighting to create adjusted cumulative incidence functions. This method is equivalent to direct standardization when the weight model is saturated. No assumptions about the form of the cumulative incidence functions are required. The method allows studying associations between treatment and the different types of event under study, while focusing on the earliest event only. We present a SAS macro implementing this method and we provide a worked example. PMID:27084321

  6. Psychosocial Adjustment and Sibling Relationships in Siblings of Children with Autism Spectrum Disorder: Risk and Protective Factors

    ERIC Educational Resources Information Center

    Walton, Katherine M.; Ingersoll, Brooke R.

    2015-01-01

    This study compared sibling adjustment and relationships in siblings of children with Autism Spectrum Disorder (ASD-Sibs; n = 69) and siblings of children with typical development (TD-Sibs; n = 93). ASD-Sibs and TD-Sibs demonstrated similar emotional/behavioral adjustment. Older male ASD-Sibs were at increased risk for difficulties. Sibling…

  7. Adjusting survival estimates for premature transmitter failure: A case study from the Sacramento-San Joaquin Delta

    USGS Publications Warehouse

    Holbrook, Christopher M.; Perry, Russell W.; Brandes, Patricia L.; Adams, Noah S.

    2013-01-01

    In telemetry studies, premature tag failure causes negative bias in fish survival estimates because tag failure is interpreted as fish mortality. We used mark-recapture modeling to adjust estimates of fish survival for a previous study where premature tag failure was documented. High rates of tag failure occurred during the Vernalis Adaptive Management Plan’s (VAMP) 2008 study to estimate survival of fall-run Chinook salmon (Oncorhynchus tshawytscha) during migration through the San Joaquin River and Sacramento-San Joaquin Delta, California. Due to a high rate of tag failure, the observed travel time distribution was likely negatively biased, resulting in an underestimate of tag survival probability in this study. Consequently, the bias-adjustment method resulted in only a small increase in estimated fish survival when the observed travel time distribution was used to estimate the probability of tag survival. Since the bias-adjustment failed to remove bias, we used historical travel time data and conducted a sensitivity analysis to examine how fish survival might have varied across a range of tag survival probabilities. Our analysis suggested that fish survival estimates were low (95% confidence bounds range from 0.052 to 0.227) over a wide range of plausible tag survival probabilities (0.48–1.00), and this finding is consistent with other studies in this system. When tags fail at a high rate, available methods to adjust for the bias may perform poorly. Our example highlights the importance of evaluating the tag life assumption during survival studies, and presents a simple framework for evaluating adjusted survival estimates when auxiliary travel time data are available.

  8. Are Chinese consumers at risk due to exposure to metals in crayfish? A bioaccessibility-adjusted probabilistic risk assessment.

    PubMed

    Peng, Qian; Nunes, Luís M; Greenfield, Ben K; Dang, Fei; Zhong, Huan

    2016-03-01

    Freshwater crayfish, the world's third largest crustacean species, has been reported to accumulate high levels of metals, while the current knowledge of potential risk associated with crayfish consumption lags behind that of finfish. We provide the first estimate of human health risk associated with crayfish (Procambarus clarkii) consumption in China, the world's largest producer and consumer of crayfish. We performed Monte Carlo Simulation on a standard risk model parameterized with local data on metal concentrations, bioaccessibility (φ), crayfish consumption rate, and consumer body mass. Bioaccessibility of metals in crayfish was found to be variable (68-95%) and metal-specific, suggesting a potential influence of metal bioaccessibility on effective metal intake. However, sensitivity analysis suggested risk of metals via crayfish consumption was predominantly explained by consumption rate (explaining >92% of total risk estimate variability), rather than metals concentration, bioaccessibility, or body mass. Mean metal concentrations (As, Cd, Cu, Ni, Pb, Se and Zn) in surveyed crayfish samples from 12 provinces in China conformed to national safety standards. However, risk calculation of φ-modified hazard quotient (HQ) and hazard index (HI) suggested that crayfish metals may pose a health risk for very high rate consumers, with a HI of over 24 for the highest rate consumers. Additionally, the φ-modified increased lifetime risk (ILTR) for carcinogenic effects due to the presence of As was above the acceptable level (10(-5)) for both the median (ILTR=2.5×10(-5)) and 90th percentile (ILTR=1.8×10(-4)), highlighting the relatively high risk of As in crayfish. Our results suggest a need to consider crayfish when assessing human dietary exposure to metals and associated health risks, especially for high crayfish-consuming populations, such as in China, USA and Sweden. PMID:26773397

  9. Antipsychotic effects on estimated 10 year coronary heart disease risk in the CATIE Schizophrenia Study

    PubMed Central

    Daumit, Gail L.; Goff, Donald C.; Meyer, Jonathan M.; Davis, Vicki G.; Nasrallah, Henry A.; McEvoy, Joseph P.; Rosenheck, Robert; Davis, Sonia M.; Hsiao, John K.; Stroup, T. Scott; Lieberman, Jeffrey A.

    2008-01-01

    Objective Persons with schizophrenia die earlier than the general population, in large part due to cardiovascular disease. The study objective was to examine effects of different antipsychotic treatments on estimates of 10 year coronary heart disease (CHD) risk calculated by the Framingham Heart Study formula. Method Change in ten-year risk for CHD was compared between treatment groups in 1125 patients followed for 18 months or until treatment discontinuation in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) Schizophrenia Trial. Results The covariate-adjusted mean change in 10-year CHD risk differed significantly between treatments. Olanzapine was associated with a 0.5% (SE 0.3) increase and quetiapine, a 0.3% (SE 0.3) increase; whereas risk decreased in patients treated with perphenazine, −0.5% (SE 0.3), risperidone, −0.6% (SE 0.3), and ziprasidone −0.6% (SE 0.4). The difference in 10-year CHD risk between olanzpaine and risperidone was statistically significant (p=0.004). Differences in estimated 10 year CHD risk between drugs were most marked in the tertile of subjects with a baseline CHD risk of at least 10%. Among individual CHD risk factors used in the Framingham formula, only total and HDL cholesterol levels differed between treatments. Conclusions These results indicate that the impact on 10-year CHD risk differs significantly between antipsychotic agents, with olanzapine producing the largest elevation in CHD risk of the agents studied in CATIE. PMID:18775645

  10. Parametric Estimation in a Recurrent Competing Risks Model

    PubMed Central

    Peña, Edsel A.

    2014-01-01

    A resource-efficient approach to making inferences about the distributional properties of the failure times in a competing risks setting is presented. Efficiency is gained by observing recurrences of the competing risks over a random monitoring period. The resulting model is called the recurrent competing risks model (RCRM) and is coupled with two repair strategies whenever the system fails. Maximum likelihood estimators of the parameters of the marginal distribution functions associated with each of the competing risks and also of the system lifetime distribution function are presented. Estimators are derived under perfect and partial repair strategies. Consistency and asymptotic properties of the estimators are obtained. The estimation methods are applied to a data set of failures for cars under warranty. Simulation studies are used to ascertain the small sample properties and the efficiency gains of the resulting estimators. PMID:25346751

  11. Estimated soil ingestion rates for use in risk assessment

    SciTech Connect

    LaGoy, P.K.

    1987-09-01

    Assessing the risks to human health posed by contaminants present in soil requires an estimate of likely soil ingestion rates. In the past, direct measurements of soil ingestion were not available and risk assessors were forced to estimate soil ingestion rates based on observations of mouthing behavior and measurements of soil on hands. Recently, empirical data on soil ingestion rates have become available from two sources. Although preliminary, these data can be used to derive better estimates of soil ingestion rates for use in risk assessments. Estimates of average soil ingestion rates derived in this paper range from 25 to 100 mg/day, depending on the age of the individual at risk. Maximum soil ingestion rates that are unlikely to underestimate exposure range from 100 to 500 mg. A value of 5000 mg/day is considered a reasonable estimate of a maximum single-day exposure for a child with habitual pica. 12 references.

  12. Estimating Risk: Stereotype Amplification and the Perceived Risk of Criminal Victimization

    ERIC Educational Resources Information Center

    Quillian, Lincoln; Pager, Devah

    2010-01-01

    This paper considers the process by which individuals estimate the risk of adverse events, with particular attention to the social context in which risk estimates are formed. We compare subjective probability estimates of crime victimization to actual victimization experiences among respondents from the 1994 to 2002 waves of the Survey of Economic…

  13. Estimated GFR Associates with Cardiovascular Risk Factors Independently of Measured GFR

    PubMed Central

    Melsom, Toralf; Ingebretsen, Ole C.; Jenssen, Trond; Njølstad, Inger; Solbu, Marit D.; Toft, Ingrid; Eriksen, Bjørn O.

    2011-01-01

    Estimation of the GFR (eGFR) using creatinine- or cystatin C–based equations is imperfect, especially when the true GFR is normal or near-normal. Modest reductions in eGFR from the normal range variably predict cardiovascular morbidity. If eGFR associates not only with measured GFR (mGFR) but also with cardiovascular risk factors, the effects of these non–GFR-related factors might bias the association between eGFR and outcome. To investigate these potential non–GFR-related associations between eGFR and cardiovascular risk factors, we measured GFR by iohexol clearance in a sample from the general population (age 50 to 62 years) without known cardiovascular disease, diabetes, or kidney disease. Even after adjustment for mGFR, eGFR associated with traditional cardiovascular risk factors in multiple regression analyses. More risk factors influenced cystatin C–based eGFR than creatinine-based eGFR, adjusted for mGFR, and some of the risk factors exhibited nonlinear effects in generalized additive models (P < 0.05). These results suggest that eGFR, calculated using standard creatinine- or cystatin C–based equations, partially depends on factors other than the true GFR. Thus, estimates of cardiovascular risk associated with small changes in eGFR must be interpreted with caution. PMID:21454717

  14. Teacher-child relationships and behavioral adjustment: transactional links for preschool boys at risk.

    PubMed

    Roorda, Debora L; Verschueren, Karine; Vancraeyveldt, Caroline; Van Craeyevelt, Sanne; Colpin, Hilde

    2014-10-01

    In this short-term longitudinal study, transactional links between teacher-child relationships and behavioral adjustment were investigated in a sample of preschool boys (N=175) at risk for developing externalizing problems. Teachers (N=175) reported about the quality of the teacher-child relationship (i.e., Closeness, Conflict, and Dependency) and about children's behavioral adjustment (i.e., Externalizing Behavior, Internalizing Behavior, and Prosocial Behavior) at three occasions within one school year. Cross-lagged path-analytic models showed positive bidirectional associations between Conflict and both Externalizing and Internalizing Behavior from Time 1 to Time 2, but not from Time 2 to Time 3. In addition, there was a transactional sequence with more Conflict at Time 1 leading to less Prosocial Behavior at Time 2 which, in turn, predicted more Conflict at Time 3. Closeness was reciprocally and positively related to Prosocial Behavior over time, and was positively and unidirectionally predicted by Internalizing Behavior. Dependency showed positive reciprocal links with Internalizing Behavior over time, and negatively and unidirectionally predicted Prosocial Behavior. These findings suggest that interventions may be most effective if they adjust their focus and strategy depending on children's specific behavioral and relational needs. PMID:25267171

  15. Behavioural Adjustment in Response to Increased Predation Risk: A Study in Three Duck Species

    PubMed Central

    Zimmer, Cédric; Boos, Mathieu; Bertrand, Frédéric; Robin, Jean-Patrice; Petit, Odile

    2011-01-01

    Predation directly triggers behavioural decisions designed to increase immediate survival. However, these behavioural modifications can have long term costs. There is therefore a trade-off between antipredator behaviours and other activities. This trade-off is generally considered between vigilance and only one other behaviour, thus neglecting potential compensations. In this study, we considered the effect of an increase in predation risk on the diurnal time-budget of three captive duck species during the wintering period. We artificially increased predation risk by disturbing two groups of 14 mallard and teals at different frequencies, and one group of 14 tufted ducks with a radio-controlled stressor. We recorded foraging, vigilance, preening and sleeping durations the week before, during and after disturbance sessions. Disturbed groups were compared to an undisturbed control group. We showed that in all three species, the increase in predation risk resulted in a decrease in foraging and preening and led to an increase in sleeping. It is worth noting that contrary to common observations, vigilance did not increase. However, ducks are known to be vigilant while sleeping. This complex behavioural adjustment therefore seems to be optimal as it may allow ducks to reduce their predation risk. Our results highlight the fact that it is necessary to encompass the whole individual time-budget when studying behavioural modifications under predation risk. Finally, we propose that studies of behavioural time-budget changes under predation risk should be included in the more general framework of the starvation-predation risk trade-off. PMID:21533055

  16. Estimating Risk: Stereotype Amplification and the Perceived Risk of Criminal Victimization.

    PubMed

    Quillian, Lincoln; Pager, Devah

    2010-03-01

    This paper considers the process by which individuals estimate the risk of adverse events, with particular attention to the social context in which risk estimates are formed. We compare subjective probability estimates of crime victimization to actual victimization experiences among respondents from the 1994 to 2002 waves of the Survey of Economic Expectations (Dominitz and Manski 2002). Using zip code identifiers, we then match these survey data to local area characteristics from the census. The results show that: (1) the risk of criminal victimization is significantly overestimated relative to actual rates of victimization or other negative events; (2) neighborhood racial composition is strongly associated with perceived risk of victimization, whereas actual victimization risk is driven by nonracial neighborhood characteristics; and (3) white respondents appear more strongly affected by racial composition than nonwhites in forming their estimates of risk. We argue these results support a model of stereotype amplification in the formation of risk estimates. Implications for persistent racial inequality are considered. PMID:20686631

  17. Estimating Risk: Stereotype Amplification and the Perceived Risk of Criminal Victimization

    PubMed Central

    QUILLIAN, LINCOLN; PAGER, DEVAH

    2010-01-01

    This paper considers the process by which individuals estimate the risk of adverse events, with particular attention to the social context in which risk estimates are formed. We compare subjective probability estimates of crime victimization to actual victimization experiences among respondents from the 1994 to 2002 waves of the Survey of Economic Expectations (Dominitz and Manski 2002). Using zip code identifiers, we then match these survey data to local area characteristics from the census. The results show that: (1) the risk of criminal victimization is significantly overestimated relative to actual rates of victimization or other negative events; (2) neighborhood racial composition is strongly associated with perceived risk of victimization, whereas actual victimization risk is driven by nonracial neighborhood characteristics; and (3) white respondents appear more strongly affected by racial composition than nonwhites in forming their estimates of risk. We argue these results support a model of stereotype amplification in the formation of risk estimates. Implications for persistent racial inequality are considered. PMID:20686631

  18. Adjustments of the Pesticide Risk Index Used in Environmental Policy in Flanders

    PubMed Central

    Fevery, Davina; Peeters, Bob; Lenders, Sonia; Spanoghe, Pieter

    2015-01-01

    Indicators are used to quantify the pressure of pesticides on the environment. Pesticide risk indicators typically require weighting environmental exposure by a no effect concentration. An indicator based on spread equivalents (ΣSeq) is used in environmental policy in Flanders (Belgium). The pesticide risk for aquatic life is estimated by weighting active ingredient usage by the ratio of their maximum allowable concentration and their soil halflife. Accurate estimates of total pesticide usage in the region are essential in such calculations. Up to 2012, the environmental impact of pesticides was estimated on sales figures provided by the Federal Government. Since 2013, pesticide use is calculated based on results from the Farm Accountancy Data Network (FADN). The estimation of pesticide use was supplemented with data for non-agricultural use based on sales figures of amateur use provided by industry and data obtained from public services. The Seq-indicator was modified to better reflect reality. This method was applied for the period 2009-2012 and showed differences between estimated use and sales figures of pesticides. The estimated use of pesticides based on accountancy data is more accurate compared to sales figures. This approach resulted in a better view on pesticide use and its respective environmental impact in Flanders. PMID:26046655

  19. [Epidemiological data and radiation risk estimates].

    PubMed

    Cardis, E

    2002-01-01

    The results of several major epidemiology studies on populations with particular exposure to ionizing radiation should become available during the first years of the 21(st) century. These studies are expected to provide answers to a number of questions concerning public health and radiation protection. Most of the populations concerned were accidentally exposed to radiation in ex-USSR or elsewhere or in a nuclear industrial context. The results will complete and test information on risk coming from studies among survivors of the Hiroshima and Nagasaki atomic bombs, particularly studies on the effects of low dose exposure and prolonged low-dose exposure, of different types of radiation, and environmental and host-related factors which could modify the risk of radiation-induced effects. These studies are thus important to assess the currently accepted scientific evidence on radiation protection for workers and the general population. In addition, supplementary information on radiation protection could be provided by formal comparisons and analyses combining data from populations with different types of exposure. Finally, in order to provide pertinent information for public health and radiation protection, future epidemiology studies should be targeted and designed to answer specific questions, concerning, for example, the risk for specific populations (children, patients, people with genetic predisposition). An integrated approach, combining epidemiology and studies on the mechanisms of radiation induction should provide particularly pertinent information. PMID:11938114

  20. Using sightability-adjusted brood-pair ratios to estimate waterfowl productivity

    USGS Publications Warehouse

    Pagano, Anthony M.; Amundson, Courtney; Pieron, Matthew R.; Arnold, Todd W.; Kimmel, Timothy C.

    2014-01-01

    Historically, biologists used brood-pair ratios (BPRs) as an index to waterfowl productivity to help guide management decisions and evaluate conservation practices. However, BPRs are biased by imperfect detection probabilities, especially for broods. We conducted roadside surveys for breeding waterfowl pairs on 7–8 study sites in the springs of 2006–2008 in northeastern North Dakota, USA. Later each year, we conducted replicate counts of broods on the same wetlands and used mark–recapture methods to estimate sightability-adjusted BPRs (SA-BPRs). Traditional roadside brood surveys detected only 30–45% of the available broods, depending on species. We explored the potential for using SA-BPRs to measure hen success (i.e., the probability a female hatches ≥1 egg across all nesting attempts) for mallards (Anas platyrhynchos) and other upland-nesting dabbling ducks (Anas spp.). We found that SA-BPRs explained 40% of the variation in hen success over 5 species of dabbling ducks, and we were able to detect an effect of predator reduction on hen success in combined dabblers, but not in mallards alone. However, we found no relationship between SA-BPRs and mallard fledging rates (hen success × initial brood size × duckling survival). Our results suggest that SA-BPRs can provide a cost-effective alternative to traditional measures of productivity such as nesting success, but not to measures of duckling survival. Nevertheless, SA-BPRs may be useful in areas where traditional measures of waterfowl productivity are logistically or financially challenging.

  1. Thinking Concretely Increases the Perceived Likelihood of Risks: The Effect of Construal Level on Risk Estimation.

    PubMed

    Lermer, Eva; Streicher, Bernhard; Sachs, Rainer; Raue, Martina; Frey, Dieter

    2016-03-01

    Recent findings on construal level theory (CLT) suggest that abstract thinking leads to a lower estimated probability of an event occurring compared to concrete thinking. We applied this idea to the risk context and explored the influence of construal level (CL) on the overestimation of small and underestimation of large probabilities for risk estimates concerning a vague target person (Study 1 and Study 3) and personal risk estimates (Study 2). We were specifically interested in whether the often-found overestimation of small probabilities could be reduced with abstract thinking, and the often-found underestimation of large probabilities was reduced with concrete thinking. The results showed that CL influenced risk estimates. In particular, a concrete mindset led to higher risk estimates compared to an abstract mindset for several adverse events, including events with small and large probabilities. This suggests that CL manipulation can indeed be used for improving the accuracy of lay people's estimates of small and large probabilities. Moreover, the results suggest that professional risk managers' risk estimates of common events (thus with a relatively high probability) could be improved by adopting a concrete mindset. However, the abstract manipulation did not lead managers to estimate extremely unlikely events more accurately. Potential reasons for different CL manipulation effects on risk estimates' accuracy between lay people and risk managers are discussed. PMID:26111548

  2. The who, what, and why of risk adjustment: a technology on the cusp of adoption.

    PubMed

    Blumenthal, David; Weissman, Joel S; Wachterman, Melissa; Weil, Evette; Stafford, Randall S; Perrin, James M; Ferris, Timothy G; Kuhlthau, Karen; Kaushal, Rainu; Iezzoni, Lisa I

    2005-06-01

    Risk adjustment (RA) consists of a series of techniques that account for the health status of patients when predicting or explaining costs of health care for defined populations or for evaluating retrospectively the performance of providers who care for them. Although the federal government seems to have settled on an approach to RA for Medicare Advantage programs, adoption and implementation of RA techniques elsewhere have proceeded much more slowly than was anticipated. This article examines factors affecting the adoption and use of RA outside the Medicare program using case studies in six U.S. health care markets (Baltimore, Seattle, Denver, Cleveland, Phoenix, and Atlanta) as of 2001. We found that for purchasing decisions, RA was used exclusively by public agencies. In the private sector, use of risk adjustment was uncommon and scattered and assumed informal and unexpected forms. The most common private sector use of RA was by health plans, which occasionally employed RA in negotiations with purchasers or to allocate resources internally among providers. The article uses classic technology diffusion theory to explain the adoption and use of RA in these six markets and derives lessons for health policy generally and for the future of RA in particular. For health policy generally, the differing experiences of public and private actors with RA serve as markers of the divergent paths that public and private health care sectors are pursuing with respect to managed care and risk sharing. For the future of RA in particular, its history suggests the need for health service researchers to consider barriers to use adoption and new analytic technologies as they develop them. PMID:16089112

  3. ITER- International Toxicity Estimates for Risk, new TOXNET database.

    PubMed

    Tomasulo, Patricia

    2005-01-01

    ITER, the International Toxicity Estimates for Risk database, joined the TOXNET system in the winter of 2004. ITER features international comparisons of environmental health risk assessment information and contains over 620 chemical records. ITER includes data from the EPA, Health Canada, the National Institute of Public Health and the Environment of the Netherlands, and other organizations that provide risk values that have been peer-reviewed. PMID:15760833

  4. Risk-adjusting outcomes of mental health and substance-related care: a review of the literature.

    PubMed

    Hermann, Richard C; Rollins, Caitlin K; Chan, Jeffrey A

    2007-01-01

    Risk adjustment is increasingly recognized as crucial to refining health care reimbursement and to comparing provider performance in terms of quality and outcomes of care. Risk adjustment for mental and substance use conditions has lagged behind other areas of medicine, but model development specific to these conditions has accelerated in recent years. After describing outcomes of mental health and substance-related care and associated risk factors, we review research studies on risk adjustment meeting the following criteria: (1) publication in a peer-reviewed journal between 1980 and 2002, (2) evaluation of one or more multivariate models used to risk-adjust comparisons of utilization, cost, or clinical outcomes of mental or substance use conditions across providers, and (3) quantitative assessment of the proportion of variance explained by patient characteristics in the model (e.g., R(2) or c-statistic). We identified 36 articles that included 72 models addressing utilization, 74 models of expenditures, and 15 models of clinical outcomes. Models based on diagnostic and sociodemographic information available from administrative data sets explained an average 6.7% of variance, whereas models using more detailed sources of data explained a more robust 22.8%. Results are appraised in the context of the mental health care system's needs for risk adjustment; we assess what has been accomplished, where gaps remain, and directions for future development. PMID:17454175

  5. The Impact of Ecological Risk and Perceived Discrimination on the Psychological Adjustment of African American and European American Youth

    ERIC Educational Resources Information Center

    Prelow, Hazel M.; Danoff-Burg, Sharon; Swenson, Rebecca R.; Pulgiano, Dana

    2004-01-01

    The purpose of the present study was to examine the role of cumulative ecological risk (i.e., neighborhood disadvantage and ecologically salient stressful events) and perceived discrimination on the psychological adjustment of urban African American and European American youth. Findings indicated that both cumulative ecological risk and perceived…

  6. 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.

    PubMed

    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. PMID:24966220

  7. The Relationship of Medicaid Payment Rates, Bed Constraint Policies, and Risk-Adjusted Pressure Ulcers

    PubMed Central

    Grabowski, David C; Angelelli, Joseph J

    2004-01-01

    Objective To examine the effect of Medicaid reimbursement rates on nursing home quality in the presence of certificate-of-need (CON) and construction moratorium laws. Data Sources/Study Setting A single cross-section of Medicaid certified nursing homes in 1999 (N=13,736). Study Design A multivariate regression model was used to examine the effect of Medicaid payment rates and other explanatory variables on risk-adjusted pressure ulcer incidence. The model is alternatively considered for all U.S. nursing home markets, those most restrictive markets, and those high-Medicaid homes to isolate potentially resource-poor environments. Data Extraction Methods A merged data file was constructed with resident-level information from the Minimum Data Set, facility-level information from the On-Line, Survey, Certification, and Reporting (OSCAR) system and market- and state-level information from various published sources. Principal Findings In the analysis of all U.S. markets, there was a positive relationship between the Medicaid payment rate and nursing home quality. The results from this analysis imply that a 10 percent increase in Medicaid payment was associated with a 1.5 percent decrease in the incidence of risk-adjusted pressure ulcers. However, there was a limited association between Medicaid payment rates and quality in the most restrictive markets. Finally, there was a strong relationship between Medicaid payment and quality in high-Medicaid homes providing strong evidence that the level of Medicaid payment is especially important within resource poor facilities. Conclusions These findings provide support for the idea that increased Medicaid reimbursement may be an effective means toward improving nursing home quality, although CON and moratorium laws may mitigate this relationship. PMID:15230928

  8. Characterization of the human kinetic adjustment factor for the health risk assessment of environmental contaminants.

    PubMed

    Valcke, Mathieu; Krishnan, Kannan

    2014-03-01

    A default uncertainty factor of 3.16 (√10) is applied to account for interindividual variability in toxicokinetics when performing non-cancer risk assessments. Using relevant human data for specific chemicals, as WHO/IPCS suggests, it is possible to evaluate, and replace when appropriate, this default factor by quantifying chemical-specific adjustment factors for interindividual variability in toxicokinetics (also referred to as the human kinetic adjustment factor, HKAF). The HKAF has been determined based on the distributions of pharmacokinetic parameters (e.g., half-life, area under the curve, maximum blood concentration) in relevant populations. This article focuses on the current state of knowledge of the use of physiologically based algorithms and models in characterizing the HKAF for environmental contaminants. The recent modeling efforts on the computation of HKAF as a function of the characteristics of the population, chemical and its mode of action (dose metrics), as well as exposure scenario of relevance to the assessment are reviewed here. The results of these studies, taken together, suggest the HKAF varies as a function of the sensitive subpopulation and dose metrics of interest, exposure conditions considered (route, duration, and intensity), metabolic pathways involved and theoretical model underlying its computation. The HKAF seldom exceeded the default value of 3.16, except in very young children (i.e., <≈ 3 months) and when the parent compound is the toxic moiety. Overall, from a public health perspective, the current state of knowledge generally suggest that the default uncertainty factor is sufficient to account for human variability in non-cancer risk assessments of environmental contaminants. PMID:24038072

  9. Estimating the re-identification risk of clinical data sets

    PubMed Central

    2012-01-01

    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. PMID:22776564

  10. [Application of spatial relative risk estimation in communicable disease risk evaluation].

    PubMed

    Zhang, Yewu; Guo, Qing; Wang, Xiaofeng; Yu, Meng; Su, Xuemei; Dong, Yan; Zhang, Chunxi

    2015-05-01

    This paper summaries the application of adaptive kernel density algorithm in the spatial relative risk estimation of communicable diseases by using the reported data of infectious diarrhea (other than cholera, dysentery, typhoid and paratyphoid) in Ludian county and surrounding area in Yunnan province in 2013. Statistically significant fluctuations in an estimated risk function were identified through the use of asymptotic tolerance contours, and finally these data were visualized though disease mapping. The results of spatial relative risk estimation and disease mapping showed that high risk areas were in southeastern Shaoyang next to Ludian. Therefore, the spatial relative risk estimation of disease by using adaptive kernel density algorithm and disease mapping technique is a powerful method in identifying high risk population and areas. PMID:26080648

  11. Using linked birth, notification, hospital and mortality data to examine false-positive meningococcal disease reporting and adjust disease incidence estimates for children in New South Wales, Australia.

    PubMed

    Gibson, A; Jorm, L; McIntyre, P

    2015-09-01

    Meningococcal disease is a rare, rapidly progressing condition which may be difficult to diagnose, disproportionally affects children, and has high morbidity and mortality. Accurate incidence estimates are needed to monitor the effectiveness of vaccination and treatment. We used linked notification, hospital, mortality and birth data for all children of an Australian state (2000-2007) to estimate the incidence of meningococcal disease. A total of 595 cases were notified, 684 cases had a hospital diagnosis, and 26 cases died from meningococcal disease. All deaths were notified, but only 68% (466/684) of hospitalized cases. Of non-notified hospitalized cases with more than one clinical admission, most (90%, 103/114) did not have meningococcal disease recorded as their final diagnosis, consistent with initial 'false-positive' hospital meningococcal disease diagnosis. After adjusting for false-positive rates in hospital data, capture-recapture estimation suggested that up to four cases of meningococcal disease may not have been captured in either notification or hospital records. The estimated incidence of meningococcal disease in NSW-born and -resident children aged 0-14 years was 5·1-5·4 cases/100 000 child-years at risk, comparable to international estimates using similar methods, but lower than estimates based on hospital data. PMID:25573266

  12. Adjusting lidar-derived digital terrain models in coastal marshes based on estimated aboveground biomass density

    SciTech Connect

    Medeiros, Stephen; Hagen, Scott; Weishampel, John; Angelo, James

    2015-03-25

    Digital elevation models (DEMs) derived from airborne lidar are traditionally unreliable in coastal salt marshes due to the inability of the laser to penetrate the dense grasses and reach the underlying soil. To that end, we present a novel processing methodology that uses ASTER Band 2 (visible red), an interferometric SAR (IfSAR) digital surface model, and lidar-derived canopy height to classify biomass density using both a three-class scheme (high, medium and low) and a two-class scheme (high and low). Elevation adjustments associated with these classes using both median and quartile approaches were applied to adjust lidar-derived elevation values closer to true bare earth elevation. The performance of the method was tested on 229 elevation points in the lower Apalachicola River Marsh. The two-class quartile-based adjusted DEM produced the best results, reducing the RMS error in elevation from 0.65 m to 0.40 m, a 38% improvement. The raw mean errors for the lidar DEM and the adjusted DEM were 0.61 ± 0.24 m and 0.32 ± 0.24 m, respectively, thereby reducing the high bias by approximately 49%.

  13. Adjusting lidar-derived digital terrain models in coastal marshes based on estimated aboveground biomass density

    DOE PAGESBeta

    Medeiros, Stephen; Hagen, Scott; Weishampel, John; Angelo, James

    2015-03-25

    Digital elevation models (DEMs) derived from airborne lidar are traditionally unreliable in coastal salt marshes due to the inability of the laser to penetrate the dense grasses and reach the underlying soil. To that end, we present a novel processing methodology that uses ASTER Band 2 (visible red), an interferometric SAR (IfSAR) digital surface model, and lidar-derived canopy height to classify biomass density using both a three-class scheme (high, medium and low) and a two-class scheme (high and low). Elevation adjustments associated with these classes using both median and quartile approaches were applied to adjust lidar-derived elevation values closer tomore » true bare earth elevation. The performance of the method was tested on 229 elevation points in the lower Apalachicola River Marsh. The two-class quartile-based adjusted DEM produced the best results, reducing the RMS error in elevation from 0.65 m to 0.40 m, a 38% improvement. The raw mean errors for the lidar DEM and the adjusted DEM were 0.61 ± 0.24 m and 0.32 ± 0.24 m, respectively, thereby reducing the high bias by approximately 49%.« less

  14. Antimicrobial Stewardship in Long-Term Care: Metrics and Risk Adjustment.

    PubMed

    Mylotte, Joseph M

    2016-07-01

    An antimicrobial stewardship program (ASP) has been recommended for long-term care facilities because of the increasing problem of antibiotic resistance in this setting to improve prescribing and decrease adverse events. Recommendations have been made for the components of such a program, but there is little evidence to support any specific methodology at the present time. The recommendations make minimal reference to metrics, an essential component of any ASP, to monitor the results of interventions. This article focuses on the role of antibiotic use metrics as part of an ASP for long-term care. Studies specifically focused on development of antibiotic use metrics for long-term care are reviewed. It is stressed that these metrics should be considered as an integral part of an ASP in long-term care. In order to develop benchmarks for antibiotic use for long-term care, there must be appropriate risk adjustment for interfacility comparisons and quality improvement. Studies that have focused on resident functional status as a risk factor for infection and antibiotic use are reviewed. Recommendations for the potentially most useful and feasible metrics for long-term care are provided along with recommendations for future research. PMID:27233489

  15. Risk-Adjusted Analysis of Relevant Outcome Drivers for Patients after More Than Two Kidney Transplants

    PubMed Central

    Kousoulas, Lampros; Vondran, Florian W. R.; Syryca, Paulina; Klempnauer, Juergen; Schrem, Harald; Lehner, Frank

    2015-01-01

    Renal transplantation is the treatment of choice for patients suffering end-stage renal disease, but as the long-term renal allograft survival is limited, most transplant recipients will face graft loss and will be considered for a retransplantation. The goal of this study was to evaluate the patient and graft survival of the 61 renal transplant recipients after second or subsequent renal transplantation, transplanted in our institution between 1990 and 2010, and to identify risk factors related to inferior outcomes. Actuarial patient survival was 98.3%, 94.8%, and 88.2% after one, three, and five years, respectively. Actuarial graft survival was 86.8%, 80%, and 78.1% after one, three, and five years, respectively. Risk-adjusted analysis revealed that only age at the time of last transplantation had a significant influence on patient survival, whereas graft survival was influenced by multiple immunological and surgical factors, such as the number of HLA mismatches, the type of immunosuppression, the number of surgical complications, need of reoperation, primary graft nonfunction, and acute rejection episodes. In conclusion, third and subsequent renal transplantation constitute a valid therapeutic option, but inferior outcomes should be expected among elderly patients, hyperimmunized recipients, and recipients with multiple operations at the site of last renal transplantation. PMID:25722883

  16. Population-Adjusted Street Connectivity, Urbanicity and Risk of Obesity in the U.S

    PubMed Central

    Wang, Fahui; Wen, Ming; Xu, Yanqing

    2013-01-01

    Street connectivity, defined as the number of (3-way or more) intersections per area unit, is an important index of built environments as a proxy for walkability in a neighborhood. This paper examines its geographic variations across the rural-urban continuum (urbanicity), major racial-ethnic groups and various poverty levels. The population-adjusted street connectivity index is proposed as a better measure than the regular index for a large area such as county due to likely concentration of population in limited space within the large area. Based on the data from the Behavioral Risk Factor Surveillance System (BRFSS), this paper uses multilevel modeling to analyze its association with physical activity and obesity while controlling for various individual and county-level variables. Analysis of data subsets indicates that the influences of individual and county-level variables on obesity risk vary across areas of different urbanization levels. The positive influence of street connectivity on obesity control is limited to the more but not the mostly urbanized areas. This demonstrates the value of obesogenic environment research in different geographic settings, helps us reconcile and synthesize some seemingly contradictory results reported in different studies, and also promotes that effective policies need to be highly sensitive to the diversity of demographic groups and geographically adaptable. PMID:23667278

  17. Population-based absolute risk estimation with survey data.

    PubMed

    Kovalchik, Stephanie A; Pfeiffer, Ruth M

    2014-04-01

    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

  18. On cancer risk estimation of urban air pollution.

    PubMed Central

    Törnqvist, M; Ehrenberg, L

    1994-01-01

    The usefulness of data from various sources for a cancer risk estimation of urban air pollution is discussed. Considering the irreversibility of initiations, a multiplicative model is preferred for solid tumors. As has been concluded for exposure to ionizing radiation, the multiplicative model, in comparison with the additive model, predicts a relatively larger number of cases at high ages, with enhanced underestimation of risks by short follow-up times in disease-epidemiological studies. For related reasons, the extrapolation of risk from animal tests on the basis of daily absorbed dose per kilogram body weight or per square meter surface area without considering differences in life span may lead to an underestimation, and agreements with epidemiologically determined values may be fortuitous. Considering these possibilities, the most likely lifetime risks of cancer death at the average exposure levels in Sweden were estimated for certain pollution fractions or indicator compounds in urban air. The risks amount to approximately 50 deaths per 100,000 for inhaled particulate organic material (POM), with a contribution from ingested POM about three times larger, and alkenes, and butadiene cause 20 deaths, respectively, per 100,000 individuals. Also, benzene and formaldehyde are expected to be associated with considerable risk increments. Comparative potency methods were applied for POM and alkenes. Due to incompleteness of the list of compounds considered and the uncertainties of the above estimates, the total risk calculation from urban air has not been attempted here. PMID:7821292

  19. Relations of Growth in Effortful Control to Family Income, Cumulative Risk, and Adjustment in Preschool-age Children

    PubMed Central

    Lengua, Liliana J.; Moran, Lyndsey; Zalewski, Maureen; Ruberry, Erika; Kiff, Cara; Thompson, Stephanie

    2014-01-01

    The study examined growth in effortful control (executive control, delay ability) in relation to income, cumulative risk (aggregate of demographic and psychosocial risk factors), and adjustment in 306 preschool-age children (50% girls, 50% boys) from families representing a range of income (29% at- or near-poverty; 28% lower-income; 25% middle-income; 18% upper-income), with 4 assessments starting at 36–40 mos. Income was directly related to levels of executive control and delay ability. Cumulative risk accounted for the effects of income on delay ability but not executive control. Higher initial executive control and slope of executive control and delay ability predicted academic readiness, whereas levels, but not growth, of executive control and delay ability predicted social competence and adjustment problems. Low income is a marker for lower effortful control, which demonstrates additive or mediating effects in the relation of income to children’s preschool adjustment. PMID:25253079

  20. Relations of growth in effortful control to family income, cumulative risk, and adjustment in preschool-age children.

    PubMed

    Lengua, Liliana J; Moran, Lyndsey; Zalewski, Maureen; Ruberry, Erika; Kiff, Cara; Thompson, Stephanie

    2015-05-01

    The study examined growth in effortful control (executive control, delay ability) in relation to income, cumulative risk (aggregate of demographic and psychosocial risk factors), and adjustment in 306 preschool-age children (50 % girls, 50 % boys) from families representing a range of income (29 % at- or near-poverty; 28 % lower-income; 25 % middle-income; 18 % upper-income), with 4 assessments starting at 36-40 month. Income was directly related to levels of executive control and delay ability. Cumulative risk accounted for the effects of income on delay ability but not executive control. Higher initial executive control and slope of executive control and delay ability predicted academic readiness, whereas levels, but not growth, of executive control and delay ability predicted social competence and adjustment problems. Low income is a marker for lower effortful control, which demonstrates additive or mediating effects in the relation of income to children's preschool adjustment. PMID:25253079

  1. Real-time adjustment of satellite-based rainfall estimates using the conditional mean: hydrological validation over French Guiana

    NASA Astrophysics Data System (ADS)

    Brochart, David; Andréassian, Vazken

    2015-04-01

    Satellite precipitation products are known to be plagued by large biases, which limit their use for operational applications. This communication presents a robust approach to adjust the satellite-based rainfall estimates using an intensity-dependent error correction curve, determined by taking the mean of historic ground measurements given the satellite estimates (conditional mean). We apply the procedure to seven satellite precipitation products over French Guiana and present a double validation, first at the raingage scale, and then at the catchment scale. Over the six catchments used here, the rainfall-runoff simulations are considerably improved when the correction is applied, outperforming the well-established quantile mapping technique.

  2. Update of identification and estimation of socioeconomic impacts resulting from perceived risks and changing images: An annotated bibliography

    SciTech Connect

    Nieves, L.A.; Clark, D.E.; Wernette, D.

    1991-08-01

    This annotated bibliography reviews selected literature published through August 1991 on the identification of perceived risks and methods for estimating the economic impacts of risk perception. It updates the literature review found in Argonne National Laboratory report ANL/EAIS/TM-24 (February 1990). Included in this update are (1) a literature review of the risk perception process, of the relationship between risk perception and economic impacts, of economic methods and empirical applications, and interregional market interactions and adjustments; (2) a working bibliography (that includes the documents abstracted in the 1990 report); (3) a topical index to the abstracts found in both reports; and (4) abstracts of selected articles found in this update.

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

    PubMed Central

    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

  4. Inhalation exposure or body burden? Better way of estimating risk--An application of PBPK model.

    PubMed

    Majumdar, Dipanjali; Dutta, Chirasree; Sen, Subha

    2016-01-01

    We aim to establish a new way for estimating the risk from internal dose or body burden due to exposure of benzene in human subject utilizing physiologically based pharmacokinetic (PBPK) model. We also intend to verify its applicability on human subjects exposed to different levels of benzene. We estimated personal inhalation exposure of benzene for two occupational groups namely petrol pump workers and car drivers with respect to a control group, only environmentally exposed. Benzene in personal air was pre-concentrated on charcoal followed by chemical desorption and analysis by gas chromatography equipped with flame ionization detector (GC-FID). We selected urinary trans,trans-muconic acid (t,t-MA) as biomarker of benzene exposure and measured its concentration using solid phase extraction followed by high performance liquid chromatography (HPLC). Our estimated inhalation exposure of benzene was 137.5, 97.9 and 38.7 μg/m(3) for petrol pump workers, car drivers and environmentally exposed control groups respectively which resulted in urinary t,t-MA levels of 145.4±55.3, 112.6±63.5 and 60.0±34.9 μg g(-1) of creatinine, for the groups in the same order. We deduced a derivation for estimation of body burden from urinary metabolite concentration using PBPK model. Estimation of the internal dose or body burden of benzene in human subject has been made for the first time by the measurement of t,t-MA as a urinary metabolite using physiologically based pharmacokinetic (PBPK) model as a tool. The weight adjusted total body burden of benzene was estimated to be 17.6, 11.1 and 5.0 μg kg(-1) of body weight for petrol pump workers, drivers and the environmentally exposed control group, respectively using this method. We computed the carcinogenic risk using both the estimated internal benzene body burden and external exposure values using conventional method. Our study result shows that internal dose or body burden is not proportional to level of exposure rather have a

  5. How to estimate the Value at Risk under incomplete information

    NASA Astrophysics Data System (ADS)

    de Schepper, Ann; Heijnen, Bart

    2010-03-01

    A key problem in financial and actuarial research, and particularly in the field of risk management, is the choice of models so as to avoid systematic biases in the measurement of risk. An alternative consists of relaxing the assumption that the probability distribution is completely known, leading to interval estimates instead of point estimates. In the present contribution, we show how this is possible for the Value at Risk, by fixing only a small number of parameters of the underlying probability distribution. We start by deriving bounds on tail probabilities, and we show how a conversion leads to bounds for the Value at Risk. It will turn out that with a maximum of three given parameters, the best estimates are always realized in the case of a unimodal random variable for which two moments and the mode are given. It will also be shown that a lognormal model results in estimates for the Value at Risk that are much closer to the upper bound than to the lower bound.

  6. Adjustment of Measurements with Multiplicative Errors: Error Analysis, Estimates of the Variance of Unit Weight, and Effect on Volume Estimation from LiDAR-Type Digital Elevation Models

    PubMed Central

    Shi, Yun; Xu, Peiliang; Peng, Junhuan; Shi, Chuang; Liu, Jingnan

    2014-01-01

    Modern observation technology has verified that measurement errors can be proportional to the true values of measurements such as GPS, VLBI baselines and LiDAR. Observational models of this type are called multiplicative error models. This paper is to extend the work of Xu and Shimada published in 2000 on multiplicative error models to analytical error analysis of quantities of practical interest and estimates of the variance of unit weight. We analytically derive the variance-covariance matrices of the three least squares (LS) adjustments, the adjusted measurements and the corrections of measurements in multiplicative error models. For quality evaluation, we construct five estimators for the variance of unit weight in association of the three LS adjustment methods. Although LiDAR measurements are contaminated with multiplicative random errors, LiDAR-based digital elevation models (DEM) have been constructed as if they were of additive random errors. We will simulate a model landslide, which is assumed to be surveyed with LiDAR, and investigate the effect of LiDAR-type multiplicative error measurements on DEM construction and its effect on the estimate of landslide mass volume from the constructed DEM. PMID:24434880

  7. Adjustment of measurements with multiplicative errors: error analysis, estimates of the variance of unit weight, and effect on volume estimation from LiDAR-type digital elevation models.

    PubMed

    Shi, Yun; Xu, Peiliang; Peng, Junhuan; Shi, Chuang; Liu, Jingnan

    2013-01-01

    Modern observation technology has verified that measurement errors can be proportional to the true values of measurements such as GPS, VLBI baselines and LiDAR. Observational models of this type are called multiplicative error models. This paper is to extend the work of Xu and Shimada published in 2000 on multiplicative error models to analytical error analysis of quantities of practical interest and estimates of the variance of unit weight. We analytically derive the variance-covariance matrices of the three least squares (LS) adjustments, the adjusted measurements and the corrections of measurements in multiplicative error models. For quality evaluation, we construct five estimators for the variance of unit weight in association of the three LS adjustment methods. Although LiDAR measurements are contaminated with multiplicative random errors, LiDAR-based digital elevation models (DEM) have been constructed as if they were of additive random errors. We will simulate a model landslide, which is assumed to be surveyed with LiDAR, and investigate the effect of LiDAR-type multiplicative error measurements on DEM construction and its effect on the estimate of landslide mass volume from the constructed DEM. PMID:24434880

  8. Studies on the extended Techa river cohort: cancer risk estimation

    SciTech Connect

    Kossenko, M M.; Preston, D L.; Krestinina, L Y.; Degteva, M O.; Startsev, N V.; Thomas, T; Vyushkova, O V.; Anspaugh, L R.; Napier, Bruce A. ); Kozheurov, V P.; Ron, E; Akleyev, A V.

    2001-12-01

    Initial population-based studies of riverside residents were begun in the late 1950s and in 1967 a systematic effort was undertaken to develop a well-defined fixed cohort of Techa river residents, to carry out ongoing mortality and (limited) clinical follow-up of this cohort, and to provide individualized dose estimates for cohort members. Over the past decade, extensive efforts have been made to refine the cohort definition and improve both the follow-up and dosimetry data. Analyses of the Techa river cohort can provide useful quantitative estimates of the effects of low dose rate, chronic external and internal exposures on cancer mortality and incidence and non-cancer mortality rates. These risk estimates complement quantitative risk estimates for acute exposures based on the atomic bomb survivors and chronic exposure risk estimates from worker studies, including Mayak workers and other groups with occupational radiation exposures. As the dosimetry and follow-up are refined it may also be possible to gain useful insights into risks associated with 90Sr exposures.

  9. Chronotropic response during treadmill exercise and subclinical carotid atherosclerosis after adjusting for the calibrated SCORE risk classification: a cross-sectional study.

    PubMed

    Liontou, Catherine; Chrysohoou, Christina; Skoumas, John; Panagiotakos, Demosthenes B; Pitsavos, Christos; Stefanadis, Christodoulos

    2016-02-01

    Carotid atherosclerosis (CA) and chronotropic incompetence (CI) during exercise are two independent cardiovascular risk factors. Aim of the current study was to investigate the possible association between them, in apparently healthy individuals, after adjusting for the 10-year cardiovascular disease (CVD) risk score. This cross-sectional study consisted of 139 apparently healthy subjects, 40-65 years old, who underwent treadmill exercise test (Bruce protocol used), which showed no evidence of ischemia. Heart rate reserve (HR reserve) was calculated to assess chronotropic response; a value of ≤ 0.80 is considered CI. CA was assessed by the presence of carotid plaque(s) in common and internal carotid arteries and carotid bulb bilaterally, using B-mode ultrasound. A calibrated version of SCORE (i.e., HellenicSCORE) was used to estimate the 10-year fatal CVD risk; participants were classified into low-, moderate- or high-risk group. CI was present in 7.9 % and CA in 18.7 % of the participants. After adjusting for 10-year CVD risk and other key confounders, odds of CA were 8.6 times higher in subjects with CI compared to their counterparts with normal chronotropic response to exercise. The results of the study indicate that CI during exercise can lead to high clinical suspicion of CA in apparently healthy individuals. PMID:25252777

  10. Beam filling loss adjustments for ASR-9 weather channel reflectivity estimates

    NASA Astrophysics Data System (ADS)

    Engholm, Cynthia D.; Troxel, Seth W.

    1990-10-01

    The FAA is deploying over 100 new airport surveillance radars (ASR-9) across the country. In contrast to earlier ASRs, the ASR-9 utilizes a separate digital weather processing channel to provide air traffic controllers with timely, calibrated displays of precipitation intensity. The ASR-9 utilizes dual selectable fan shaped elevation beams designed to track aircraft over a large volume. As a consequence, weather echoes received from these fan shaped beams represent vertically averaged quantities. If the precipitation only partially or nonuniformly fills the beam, then the vertically integrated reflectivity may underestimate the actual intensity of the storm. The ASR-9 weather channel corrects for this by adjusting the range dependent six level reflectivity thresholds. The appropriateness of the currently implemented correction has not been carefully examined and may require modification to take into account regional and morphological variability in storm structure. The method used to derive new beam filling loss adjustments is discussed. An extensive database of volumetric pencil beam radar data were used in conjunction with the ASR-9 simulation facility to derive adjustments aimed at calibrating the precipitation intensity reports to the maximum perceived hazard. Results from this calibration indicate that a single correction is appropriate for all sites and intensities. The new corrections yield substantially improved results over the current corrections in producing these reflectivity reports.

  11. Sensitivity of risk estimates to wildlife bioaccumulation factors in ecological risk assessment

    SciTech Connect

    Karustis, C.G.; Brewer, R.A.

    1995-12-31

    The concept of conservatism in risk assessment is well established. However, overly conservative assumptions may result in risk estimates that incorrectly predict remediation goals. Therefore, realistic assumptions should be applied in risk assessment whenever possible. A sensitivity analysis was performed on conservative (i.e. bioaccumulation factor = 1) and scientifically-derived wildlife bioaccumulation factors (BAFs) utilized to calculate risks during a terrestrial ecological risk assessment (ERA). In the first approach, 100% bioaccumulation of contaminants was assumed to estimate the transfer of contaminants through the terrestrial food chain. In the second approach, scientifically-derived BAFs were selected from the literature. For one of the measurement species selected, total risks calculated during the first approach were higher than those calculated during the second approach by two orders of magnitude. However, potential risks due to individual contaminants were not necessarily higher using the conservative approach. Potential risk due to contaminants with low actual bioaccumulation were exaggerated while potential risks due to contaminants with greater than 100% bioaccumulation were underestimated. Therefore, the use of a default of 100% bioaccumulation (BAF = 1) for all contaminants encountered during an ERA could result in cases where contaminants are incorrectly identified as risk drivers, and the calculation of incorrect ecological risk-based cleanup goals. The authors suggest using site-specific or literature-derived BAFs whenever possible and realistic BAF estimates, based upon factors such as log K{sub ow}, when BAFs are unavailable.

  12. Aerial surveys adjusted by ground surveys to estimate area occupied by black-tailed prairie dog colonies

    USGS Publications Warehouse

    Sidle, John G.; Augustine, David J.; Johnson, Douglas H.; Miller, Sterling D.; Cully, Jack F., Jr.; Reading, Richard P.

    2012-01-01

    Aerial surveys using line-intercept methods are one approach to estimate the extent of prairie dog colonies in a large geographic area. Although black-tailed prairie dogs (Cynomys ludovicianus) construct conspicuous mounds at burrow openings, aerial observers have difficulty discriminating between areas with burrows occupied by prairie dogs (colonies) versus areas of uninhabited burrows (uninhabited colony sites). Consequently, aerial line-intercept surveys may overestimate prairie dog colony extent unless adjusted by an on-the-ground inspection of a sample of intercepts. We compared aerial line-intercept surveys conducted over 2 National Grasslands in Colorado, USA, with independent ground-mapping of known black-tailed prairie dog colonies. Aerial line-intercepts adjusted by ground surveys using a single activity category adjustment overestimated colonies by ≥94% on the Comanche National Grassland and ≥58% on the Pawnee National Grassland. We present a ground-survey technique that involves 1) visiting on the ground a subset of aerial intercepts classified as occupied colonies plus a subset of intercepts classified as uninhabited colony sites, and 2) based on these ground observations, recording the proportion of each aerial intercept that intersects a colony and the proportion that intersects an uninhabited colony site. Where line-intercept techniques are applied to aerial surveys or remotely sensed imagery, this method can provide more accurate estimates of black-tailed prairie dog abundance and trends

  13. Reconstruction of financial networks for robust estimation of systemic risk

    NASA Astrophysics Data System (ADS)

    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.

  14. Multivariate Risk Adjustment of Primary Care Patient Panels in a Public Health Setting: A Comparison of Statistical Models.

    PubMed

    Hirozawa, Anne M; Montez-Rath, Maria E; Johnson, Elizabeth C; Solnit, Stephen A; Drennan, Michael J; Katz, Mitchell H; Marx, Rani

    2016-01-01

    We compared prospective risk adjustment models for adjusting patient panels at the San Francisco Department of Public Health. We used 4 statistical models (linear regression, two-part model, zero-inflated Poisson, and zero-inflated negative binomial) and 4 subsets of predictor variables (age/gender categories, chronic diagnoses, homelessness, and a loss to follow-up indicator) to predict primary care visit frequency. Predicted visit frequency was then used to calculate patient weights and adjusted panel sizes. The two-part model using all predictor variables performed best (R = 0.20). This model, designed specifically for safety net patients, may prove useful for panel adjustment in other public health settings. PMID:27576054

  15. Anticipatory postural adjustments during cutting manoeuvres in football and their consequences for knee injury risk.

    PubMed

    Mornieux, Guillaume; Gehring, Dominic; Fürst, Patrick; Gollhofer, Albert

    2014-01-01

    Anticipatory postural adjustments (APAs), i.e. preparatory positioning of the head, the trunk and the foot, are essential to initiate cutting manoeuvres during football games. The aim of the present study was to determine how APA strategies during cutting manoeuvres are influenced by a reduction of the time available to prepare the movement. Thirteen football players performed different cutting tasks, with directions of cutting either known prior to the task or indicated by a light signal occurring 850, 600 or 500 ms before ground contact. With less time available to prepare the cutting manoeuvre, the head was less orientated towards the cutting direction (P = 0.033) and the trunk was even more rotated in the opposite direction (P = 0.002), while the foot placement was not significantly influenced. Moreover, the induced higher lateral trunk flexion correlated with the increased knee abduction moment (r = 0.41; P = 0.009). Increasing lateral trunk flexion is the main strategy used to successfully perform a cutting manoeuvre when less time is available to prepare the movement. However, higher lateral trunk flexion was associated with an increased knee abduction moment and therefore an increased knee injury risk. Reducing lateral trunk flexion during cutting manoeuvres should be part of training programs seeking the optimisation of APAs. PMID:24742137

  16. Effortful control as a moderator of the relation between contextual risk factors and growth in adjustment problems

    PubMed Central

    LENGUA, LILIANA J.; BUSH, NICOLE R.; LONG, ANNA C.; KOVACS, ERICA A.; TRANCIK, ANIKA M.

    2014-01-01

    Effortful control was examined as a moderator of the relations of three domains of contextual risk factors to growth in internalizing and externalizing problems in a community sample (N = 189) of children (8–12 years at Time 1). Socioeconomic, maternal, and environmental risk factors were examined as predictors of initial levels and growth in children’s adjustment problems across 3 years. The effects of the risk factors depended on children’s level of effortful control. For children lower in effortful control, socioeconomic risk was related to significantly higher initial levels of internalizing and externalizing problems and decreases over time. However, children lower in effortful control had higher levels of problems at all three time points than children higher in effortful control. Maternal risk was associated with increases in internalizing for children lower in effortful control, and environmental risk was related to increases in internalizing and externalizing problems for children lower in effortful control, but not those higher in effortful control. Children who were lower in effortful control appeared to experience more adverse effects of contextual risk than those higher in effortful control, suggesting that interventions aimed at improving children’s effortful control might serve to protect children from increased risk of adjustment problems associated with contextual risk factors. PMID:18423092

  17. Effortful control as a moderator of the relation between contextual risk factors and growth in adjustment problems.

    PubMed

    Lengua, Liliana J; Bush, Nicole R; Long, Anna C; Kovacs, Erica A; Trancik, Anika M

    2008-01-01

    Effortful control was examined as a moderator of the relations of three domains of contextual risk factors to growth in internalizing and externalizing problems in a community sample (N = 189) of children (8-12 years at Time 1). Socioeconomic, maternal, and environmental risk factors were examined as predictors of initial levels and growth in children's adjustment problems across 3 years. The effects of the risk factors depended on children's level of effortful control. For children lower in effortful control, socioeconomic risk was related to significantly higher initial levels of internalizing and externalizing problems and decreases over time. However, children lower in effortful control had higher levels of problems at all three time points than children higher in effortful control. Maternal risk was associated with increases in internalizing for children lower in effortful control, and environmental risk was related to increases in internalizing and externalizing problems for children lower in effortful control, but not those higher in effortful control. Children who were lower in effortful control appeared to experience more adverse effects of contextual risk than those higher in effortful control, suggesting that interventions aimed at improving children's effortful control might serve to protect children from increased risk of adjustment problems associated with contextual risk factors. PMID:18423092

  18. A methodological approach to identify external factors for indicator-based risk adjustment illustrated by a cataract surgery register

    PubMed Central

    2014-01-01

    Background Risk adjustment is crucial for comparison of outcome in medical care. Knowledge of the external factors that impact measured outcome but that cannot be influenced by the physician is a prerequisite for this adjustment. To date, a universal and reproducible method for identification of the relevant external factors has not been published. The selection of external factors in current quality assurance programmes is mainly based on expert opinion. We propose and demonstrate a methodology for identification of external factors requiring risk adjustment of outcome indicators and we apply it to a cataract surgery register. Methods Defined test criteria to determine the relevance for risk adjustment are “clinical relevance” and “statistical significance”. Clinical relevance of the association is presumed when observed success rates of the indicator in the presence and absence of the external factor exceed a pre-specified range of 10%. Statistical significance of the association between the external factor and outcome indicators is assessed by univariate stratification and multivariate logistic regression adjustment. The cataract surgery register was set up as part of a German multi-centre register trial for out-patient cataract surgery in three high-volume surgical sites. A total of 14,924 patient follow-ups have been documented since 2005. Eight external factors potentially relevant for risk adjustment were related to the outcome indicators “refractive accuracy” and “visual rehabilitation” 2–5 weeks after surgery. Results The clinical relevance criterion confirmed 2 (“refractive accuracy”) and 5 (“visual rehabilitation”) external factors. The significance criterion was verified in two ways. Univariate and multivariate analyses revealed almost identical external factors: 4 were related to “refractive accuracy” and 7 (6) to “visual rehabilitation”. Two (“refractive accuracy”) and 5 (“visual rehabilitation”) factors

  19. Neoplastic potential of gastric irradiation. IV. Risk estimates

    SciTech Connect

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

    1984-12-01

    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.

  20. Rate adjusters for Medicare under capitation

    PubMed Central

    Newhouse, Joseph P.

    1986-01-01

    This article addresses three issues related to capitation. First, the average adjusted per capita cost (AAPCC) fluctuates with the mix of risks in the fee-for-service system. More sensitive adjusters in the AAPCC are needed. Second, the AAPCC, as now estimated, exhibits large geographic variance; so-called shrinkage estimators may help. Third, the AAPCC requires new adjusters to yield more homogeneous risk classes. Otherwise, the portion of the Medicare population under capitation may experience access problems at alternative delivery systems: Until such adjusters are developed, it seems better to rely upon a blend of capitation and fee-for-service than the present AAPCC. PMID:10311926

  1. Impact of work-related cancers in Taiwan-Estimation with QALY (quality-adjusted life year) and healthcare costs.

    PubMed

    Lee, Lukas Jyuhn-Hsiarn; Lin, Cheng-Kuan; Hung, Mei-Chuan; Wang, Jung-Der

    2016-12-01

    This study estimates the annual numbers of eight work-related cancers, total losses of quality-adjusted life years (QALYs), and lifetime healthcare expenditures that possibly could be saved by improving occupational health in Taiwan. Three databases were interlinked: the Taiwan Cancer Registry, the National Mortality Registry, and the National Health Insurance Research Database. Annual numbers of work-related cancers were estimated based on attributable fractions (AFs) abstracted from a literature review. The survival functions for eight cancers were estimated and extrapolated to lifetime using a semi-parametric method. A convenience sample of 8846 measurements of patients' quality of life with EQ-5D was collected for utility values and multiplied by survival functions to estimate quality-adjusted life expectancies (QALEs). The loss-of-QALE was obtained by subtracting the QALE of cancer from age- and sex-matched referents simulated from national vital statistics. The lifetime healthcare expenditures were estimated by multiplying the survival probability with mean monthly costs paid by the National Health Insurance for cancer diagnosis and treatment and summing this for the expected lifetime. A total of 3010 males and 726 females with eight work-related cancers were estimated in 2010. Among them, lung cancer ranked first in terms of QALY loss, with an annual total loss-of-QALE of 28,463 QALYs and total lifetime healthcare expenditures of US$36.6 million. Successful prevention of eight work-related cancers would not only avoid the occurrence of 3736 cases of cancer, but would also save more than US$70 million in healthcare costs and 46,750 QALYs for the Taiwan society in 2010. PMID:27413666

  2. Estimation of myocardial volume at risk from CT angiography

    NASA Astrophysics Data System (ADS)

    Zhu, Liangjia; Gao, Yi; Mohan, Vandana; Stillman, Arthur; Faber, Tracy; Tannenbaum, Allen

    2011-03-01

    The determination of myocardial volume at risk distal to coronary stenosis provides important information for prognosis and treatment of coronary artery disease. In this paper, we present a novel computational framework for estimating the myocardial volume at risk in computed tomography angiography (CTA) imagery. Initially, epicardial and endocardial surfaces, and coronary arteries are extracted using an active contour method. Then, the extracted coronary arteries are projected onto the epicardial surface, and each point on this surface is associated with its closest coronary artery using the geodesic distance measurement. The likely myocardial region at risk on the epicardial surface caused by a stenosis is approximated by the region in which all its inner points are associated with the sub-branches distal to the stenosis on the coronary artery tree. Finally, the likely myocardial volume at risk is approximated by the volume in between the region at risk on the epicardial surface and its projection on the endocardial surface, which is expected to yield computational savings over risk volume estimation using the entire image volume. Furthermore, we expect increased accuracy since, as compared to prior work using the Euclidean distance, we employ the geodesic distance in this work. The experimental results demonstrate the effectiveness of the proposed approach on pig heart CTA datasets.

  3. Estimation of the environmental risk of regulated river flow

    NASA Astrophysics Data System (ADS)

    Latu, Kilisimasi; Malano, Hector M.; Costelloe, Justin F.; Peterson, Tim J.

    2014-09-01

    A commonly accepted paradigm in environmental flow management is that a regulated river flow regime should mimic the natural hydrological regime to sustain the key attributes of freshwater ecosystems. Estimation of the environmental risk arising from flow regulation needs to consider all aspects of the flow regime when applied to water allocation decisions. We present a holistic, dynamic and robust approach that is based on a statistical analysis of the entire flow regime and accounts for flow stress indicators to produce an environmental risk time series based on the consequence of departures from the optimum flow range of a river or reach. When applied to a catchment, (Campaspe River, southern Australia) the model produced a dynamic and robust environmental risk time series that clearly showed that when the observed river flow is drawn away from the optimum range of environmental flow demand, the environmental risk increased. In addition, the model produced risk time series showing that the Campaspe River has reversed seasonal patterns of river flow due to water releases during summer periods, which altered the flow nature of the river. Hence, this resulted in higher environmental risk occurring during summer but lower in winter periods. Furthermore, we found that the vulnerability and coefficient of variation indices have the highest contributions to consequence in comparison to other indices used to calculate environmental risk.

  4. Estimation of earthquake risk curves of physical building damage

    NASA Astrophysics Data System (ADS)

    Raschke, Mathias; Janouschkowetz, Silke; Fischer, Thomas; Simon, Christian

    2014-05-01

    In this study, a new approach to quantify seismic risks is presented. Here, the earthquake risk curves for the number of buildings with a defined physical damage state are estimated for South Africa. Therein, we define the physical damage states according to the current European macro-seismic intensity scale (EMS-98). The advantage of such kind of risk curve is that its plausibility can be checked more easily than for other types. The earthquake risk curve for physical building damage can be compared with historical damage and their corresponding empirical return periods. The number of damaged buildings from historical events is generally explored and documented in more detail than the corresponding monetary losses. The latter are also influenced by different economic conditions, such as inflation and price hikes. Further on, the monetary risk curve can be derived from the developed risk curve of physical building damage. The earthquake risk curve can also be used for the validation of underlying sub-models such as the hazard and vulnerability modules.

  5. Estimating Skin Cancer Risk: Evaluating Mobile Computer-Adaptive Testing

    PubMed Central

    Djaja, Ngadiman; Janda, Monika; Olsen, Catherine M; Whiteman, David C

    2016-01-01

    Background Response burden is a major detriment to questionnaire completion rates. Computer adaptive testing may offer advantages over non-adaptive testing, including reduction of numbers of items required for precise measurement. Objective Our aim was to compare the efficiency of non-adaptive (NAT) and computer adaptive testing (CAT) facilitated by Partial Credit Model (PCM)-derived calibration to estimate skin cancer risk. Methods We used a random sample from a population-based Australian cohort study of skin cancer risk (N=43,794). All 30 items of the skin cancer risk scale were calibrated with the Rasch PCM. A total of 1000 cases generated following a normal distribution (mean [SD] 0 [1]) were simulated using three Rasch models with three fixed-item (dichotomous, rating scale, and partial credit) scenarios, respectively. We calculated the comparative efficiency and precision of CAT and NAT (shortening of questionnaire length and the count difference number ratio less than 5% using independent t tests). Results We found that use of CAT led to smaller person standard error of the estimated measure than NAT, with substantially higher efficiency but no loss of precision, reducing response burden by 48%, 66%, and 66% for dichotomous, Rating Scale Model, and PCM models, respectively. Conclusions CAT-based administrations of the skin cancer risk scale could substantially reduce participant burden without compromising measurement precision. A mobile computer adaptive test was developed to help people efficiently assess their skin cancer risk. PMID:26800642

  6. Quantile Regression Adjusting for Dependent Censoring from Semi-Competing Risks

    PubMed Central

    Li, Ruosha; Peng, Limin

    2014-01-01

    Summary In this work, we study quantile regression when the response is an event time subject to potentially dependent censoring. We consider the semi-competing risks setting, where time to censoring remains observable after the occurrence of the event of interest. While such a scenario frequently arises in biomedical studies, most of current quantile regression methods for censored data are not applicable because they generally require the censoring time and the event time be independent. By imposing rather mild assumptions on the association structure between the time-to-event response and the censoring time variable, we propose quantile regression procedures, which allow us to garner a comprehensive view of the covariate effects on the event time outcome as well as to examine the informativeness of censoring. An efficient and stable algorithm is provided for implementing the new method. We establish the asymptotic properties of the resulting estimators including uniform consistency and weak convergence. The theoretical development may serve as a useful template for addressing estimating settings that involve stochastic integrals. Extensive simulation studies suggest that the proposed method performs well with moderate sample sizes. We illustrate the practical utility of our proposals through an application to a bone marrow transplant trial. PMID:25574152

  7. The contribution of the anaesthetist to risk-adjusted mortality after cardiac surgery.

    PubMed

    Papachristofi, O; Sharples, L D; Mackay, J H; Nashef, S A M; Fletcher, S N; Klein, A A

    2016-02-01

    It is widely accepted that the performance of the operating surgeon affects outcomes, and this has led to the publication of surgical results in the public domain. However, the effect of other members of the multidisciplinary team is unknown. We studied the effect of the anaesthetist on mortality after cardiac surgery by analysing data collected prospectively over ten years of consecutive cardiac surgical cases from ten UK centres. Casemix-adjusted outcomes were analysed in models that included random-effects for centre, surgeon and anaesthetist. All cardiac surgical operations for which the EuroSCORE model is appropriate were included, and the primary outcome was in-hospital death up to three months postoperatively. A total of 110 769 cardiac surgical procedures conducted between April 2002 and March 2012 were studied, which included 127 consultant surgeons and 190 consultant anaesthetists. The overwhelming factor associated with outcome was patient risk, accounting for 95.75% of the variation for in-hospital mortality. The impact of the surgeon was moderate (intra-class correlation coefficient 4.00% for mortality), and the impact of the anaesthetist was negligible (0.25%). There was no significant effect of anaesthetist volume above ten cases per year. We conclude that mortality after cardiac surgery is primarily determined by the patient, with small but significant differences between surgeons. Anaesthetists did not appear to affect mortality. These findings do not support public disclosure of cardiac anaesthetists' results, but substantially validate current UK cardiac anaesthetic training and practice. Further research is required to establish the potential effects of very low anaesthetic caseloads and the effect of cardiac anaesthetists on patient morbidity. PMID:26511481

  8. Adjustment of costly extra-group paternity according to inbreeding risk in a cooperative mammal

    PubMed Central

    Cant, Michael A.; Sanderson, Jennifer L.

    2015-01-01

    Females of many animal species seek mating opportunities with multiple males, despite being able to obtain sufficient sperm to father their offspring from a single male. In animals that live in stable social groups, females often choose to mate outside their group resulting in extra-group paternity (EGP). One reason proposed to explain female choice for extra-group males is to obtain compatible genes, for example, in order to avoid inbreeding depression in offspring. The benefits of such extra-group paternities could be substantial if they result in fitter, outbred offspring. However, avoiding inbreeding in this way could be costly for females, for example, through retaliation by cuckolded males or through receiving aggression while prospecting for extra-group mating opportunities. We investigate the costs and benefits of EGP in the banded mongoose Mungos mungo, a cooperatively breeding mammal in which within-group mates are sometimes close relatives. We find that pups born to females that mate with extra-group males are more genetically heterozygous are heavier and are more likely to survive to independence than pups born to females that mate within their group. However, extra-group matings also involve substantial costs as they occur during violent encounters that sometimes result in injury and death. This appears to lead femalebanded mongooses to adaptively adjust EGP levels according to the current risk of inbreeding associated with mating within the group. For group-living animals, the costs of intergroup interactions may help to explain variation in both inbreeding rates and EGP within and between species. PMID:26609201

  9. Estimating and validating disability-adjusted life years at the global level: a methodological framework for cancer

    PubMed Central

    2012-01-01

    Background Disability-adjusted life years (DALYs) link data on disease occurrence to health outcomes, and they are a useful aid in establishing country-specific agendas regarding cancer control. The variables required to compute DALYs are however multiple and not readily available in many countries. We propose a methodology that derives global DALYs and validate variables and DALYs based on data from various cancer registries. Methods We estimated DALYs for four countries (Norway, Bulgaria, India and Uganda) within each category of the human development index (HDI). The following sources (indicators) were used: Globocan2008 (incidence and mortality), various cancer registries (proportion cured, proportion treated and duration of disease), treatment guidelines (duration of treatment), specific burden of disease studies (sequelae and disability weights), alongside expert opinion. We obtained country-specific population estimates and identified resource levels using the HDI, DALYs are computed as the sum of years of life lost and years lived with disabilities. Results Using mortality:incidence ratios to estimate country-specific survival, and by applying the human development index we derived country-specific estimates of the proportion cured and the proportion treated. The fit between the estimates and observed data from the cancer registries was relatively good. The final DALY estimates were similar to those computed using observed values in Norway, and in WHO’s earlier global burden of disease study. Marked cross-country differences in the patterns of DALYs by cancer sites were observed. In Norway and Bulgaria, breast, colorectal, prostate and lung cancer were the main contributors to DALYs, representing 54% and 45%, respectively, of the totals. These cancers contributed only 27% and 18%, respectively, of total DALYs in India and Uganda. Conclusions Our approach resulted in a series of variables that can be used to estimate country-specific DALYs, enabling global

  10. A Review of Expertise and Judgment Processes for Risk Estimation

    SciTech Connect

    R. L. Boring

    2007-06-01

    A major challenge of risk and reliability analysis for human errors or hardware failures is the need to enlist expert opinion in areas for which adequate operational data are not available. Experts enlisted in this capacity provide probabilistic estimates of reliability, typically comprised of a measure of central tendency and uncertainty bounds. While formal guidelines for expert elicitation are readily available, they largely fail to provide a theoretical basis for expertise and judgment. This paper reviews expertise and judgment in the context of risk analysis; overviews judgment biases, the role of training, and multivariate judgments; and provides guidance on the appropriate use of atomistic and holistic judgment processes.

  11. Comparison of Rx-defined morbidity groups and diagnosis- based risk adjusters for predicting healthcare costs in Taiwan

    PubMed Central

    2010-01-01

    Background Medication claims are commonly used to calculate the risk adjustment for measuring healthcare cost. The Rx-defined Morbidity Groups (Rx-MG) which combine the use of medication to indicate morbidity have been incorporated into the Adjusted Clinical Groups (ACG) Case Mix System, developed by the Johns Hopkins University. This study aims to verify that the Rx-MG can be used for adjusting risk and for explaining the variations in the healthcare cost in Taiwan. Methods The Longitudinal Health Insurance Database 2005 (LHID2005) was used in this study. The year 2006 was chosen as the baseline to predict healthcare cost (medication and total cost) in 2007. The final sample size amounted to 793 239 (81%) enrolees, and excluded any cases with discontinued enrolment. Two different kinds of models were built to predict cost: the concurrent model and the prospective model. The predictors used in the predictive models included age, gender, Aggregated Diagnosis Groups (ADG, diagnosis- defined morbidity groups), and Rx-defined Morbidity Groups. Multivariate OLS regression was used in the cost prediction modelling. Results The concurrent model adjusted for Rx-defined Morbidity Groups for total cost, and controlled for age and gender had a better predictive R-square = 0.618, compared to the model adjusted for ADGs (R2 = 0.411). The model combined with Rx-MGs and ADGs performed the best for concurrently predicting total cost (R2 = 0.650). For prospectively predicting total cost, the model combined Rx-MGs and ADGs (R2 = 0.382) performed better than the models adjusted by Rx-MGs (R2 = 0.360) or ADGs (R2 = 0.252) only. Similarly, the concurrent model adjusted for Rx-MGs predicting pharmacy cost had a better performance (R-square = 0.615), than the model adjusted for ADGs (R2 = 0.431). The model combined with Rx-MGs and ADGs performed the best in concurrently as well as prospectively predicting pharmacy cost (R2 = 0.638 and 0.505, respectively). The prospective models showed a

  12. Automatic parameter estimation of multicompartmental neuron models via minimization of trace error with control adjustment

    PubMed Central

    Goeritz, Marie L.; Marder, Eve

    2014-01-01

    We describe a new technique to fit conductance-based neuron models to intracellular voltage traces from isolated biological neurons. The biological neurons are recorded in current-clamp with pink (1/f) noise injected to perturb the activity of the neuron. The new algorithm finds a set of parameters that allows a multicompartmental model neuron to match the recorded voltage trace. Attempting to match a recorded voltage trace directly has a well-known problem: mismatch in the timing of action potentials between biological and model neuron is inevitable and results in poor phenomenological match between the model and data. Our approach avoids this by applying a weak control adjustment to the model to promote alignment during the fitting procedure. This approach is closely related to the control theoretic concept of a Luenberger observer. We tested this approach on synthetic data and on data recorded from an anterior gastric receptor neuron from the stomatogastric ganglion of the crab Cancer borealis. To test the flexibility of this approach, the synthetic data were constructed with conductance models that were different from the ones used in the fitting model. For both synthetic and biological data, the resultant models had good spike-timing accuracy. PMID:25008414

  13. Estimates of Radiation Doses and Cancer Risk from Food Intake in Korea

    PubMed Central

    2016-01-01

    The aim of this study was to estimate internal radiation doses and lifetime cancer risk from food ingestion. Radiation doses from food intake were calculated using the Korea National Health and Nutrition Examination Survey and the measured radioactivity of 134Cs, 137Cs, and 131I from the Ministry of Food and Drug Safety in Korea. Total number of measured data was 8,496 (3,643 for agricultural products, 644 for livestock products, 43 for milk products, 3,193 for marine products, and 973 for processed food). Cancer risk was calculated by multiplying the estimated committed effective dose and the detriment adjusted nominal risk coefficients recommended by the International Commission on Radiation Protection. The lifetime committed effective doses from the daily diet are ranged 2.957-3.710 mSv. Excess lifetime cancer risks are 14.4-18.1, 0.4-0.5, and 1.8-2.3 per 100,000 for all solid cancers combined, thyroid cancer, and leukemia, respectively. PMID:26770031

  14. Estimates of Radiation Doses and Cancer Risk from Food Intake in Korea.

    PubMed

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

    2016-01-01

    The aim of this study was to estimate internal radiation doses and lifetime cancer risk from food ingestion. Radiation doses from food intake were calculated using the Korea National Health and Nutrition Examination Survey and the measured radioactivity of (134)Cs, (137)Cs, and (131)I from the Ministry of Food and Drug Safety in Korea. Total number of measured data was 8,496 (3,643 for agricultural products, 644 for livestock products, 43 for milk products, 3,193 for marine products, and 973 for processed food). Cancer risk was calculated by multiplying the estimated committed effective dose and the detriment adjusted nominal risk coefficients recommended by the International Commission on Radiation Protection. The lifetime committed effective doses from the daily diet are ranged 2.957-3.710 mSv. Excess lifetime cancer risks are 14.4-18.1, 0.4-0.5, and 1.8-2.3 per 100,000 for all solid cancers combined, thyroid cancer, and leukemia, respectively. PMID:26770031

  15. Enhancement of radar rainfall estimates for urban hydrology through optical flow temporal interpolation and Bayesian gauge-based adjustment

    NASA Astrophysics Data System (ADS)

    Wang, Li-Pen; Ochoa-Rodríguez, Susana; Van Assel, Johan; Pina, Rui Daniel; Pessemier, Mieke; Kroll, Stefan; Willems, Patrick; Onof, Christian

    2015-12-01

    Rainfall estimates of the highest possible accuracy and resolution are required for urban hydrological applications, given the small size and fast response which characterise urban catchments. While radar rainfall estimates have the advantage of well capturing the spatial structure of rainfall fields and its variation in time, the commonly available radar rainfall products (typically at ∼1 km/5-10 min resolution) may still fail to satisfy the accuracy and resolution - in particular temporal resolution - requirements of urban hydrology. A methodology is proposed in this paper, to produce higher temporal resolution, more accurate radar rainfall estimates, suitable for urban hydrological applications. The proposed methodology entails two main steps: (1) Temporal interpolation of radar images from the originally-available temporal resolutions (i.e. 5-10 min) to finer resolutions at which local rain gauge data are commonly available (i.e. 1-2 min). This is done using a novel interpolation technique, based upon the multi-scale variational optical flow technique, and which can well capture the small-scale rainfall structures relevant at urban scales. (2) Local and dynamic gauge-based adjustment of the higher temporal resolution radar rainfall estimates is performed afterwards, by means of the Bayesian data merging method. The proposed methodology is tested using as case study a total of 8 storm events observed in the Cranbrook (UK) and Herent (BE) urban catchments, for which radar rainfall estimates, local rain gauge and depth/flow records, as well as recently calibrated urban drainage models were available. The results suggest that the proposed methodology can provide significantly improved radar rainfall estimates and thereby generate more accurate runoff simulations at urban scales, over and above the benefits derived from the mere application of Bayesian merging at the original temporal resolution at which radar estimates are available. The benefits of the proposed

  16. Risk-adjusted comparison of blood pressure and Low-Density (LDL) non-control in primary care offices

    PubMed Central

    Hammermeister, Karl; Bronsert, Michael; Henderson, William G.; Coombs, Letoynia; Hosokawa, Patrick; Brandt, Elias; Bryan, Cathy; Valuck, Robert; West, David; Liaw, Winston; Ho, Michael; Pace, Wilson

    2014-01-01

    Background Population-level control of modifiable cardiovascular disease (CVD) risk factors is suboptimal. Objectives 1) To demonstrate the use of electronically downloaded electronic health record (EHR) data to assess guideline concordance in a large cohort of primary care patients, 2) To provide a contemporary assessment of BP and LDL non-control in primary care, and 3) To demonstrate the effect of risk adjustment of rates of non-control of BP and LDL for differences in patient mix on these clinic-level performance measures. Design Observational comparative effectiveness. Patients All 232,172 adult patients ≥age 18 with ≥1 visit within two years in 33 primary care clinics with electronic health records (EHR). Interventions None. Main Measures Rates of BP and LDL non-control, based on current guidelines, were calculated from electronically downloaded EHR data. Non-control rates were risk-adjusted using multi-variable models of patient-level variables. Key Results Overall, 16.0% of the 227,122 patients with known BP and 14.9% of the 136,771 patients with known LDL were uncontrolled. Clinic-level risk-adjusted BP non-control ranged from 7.7% to 26.5%, while that for LDL ranged from 5.8% to 23.6%. Non-control rates exceeded an achievable benchmark for 85% (28/33) and 79% (26/33) of clinics for BP and LDL, respectively. Risk-adjustment significantly influences clinic rank order for rate of non-control. Conclusions We have demonstrated that the use of electronic collection of data on a large number of patients from fee-for-services, primary care clinics required for the audit and feedback of BP and LDL non-control is feasible. Non-control rates for most clinics are substantially higher than that achievable. Risk-adjustment of non-control rates results in very different clinic rank-order of clinics from non-adjusted data. PMID:24204062

  17. Cumulative Socioeconomic Status Risk, Allostatic Load, and Adjustment: A Prospective Latent Profile Analysis With Contextual and Genetic Protective Factors

    PubMed Central

    Brody, Gene H.; Yu, Tianyi; Chen, Yi-fu; Kogan, Steven M.; Evans, Gary W.; Beach, Steven R. H.; Windle, Michael; Simons, Ronald L.; Gerrard, Meg; Gibbons, Frederick X.; Philibert, Robert A.

    2012-01-01

    The health disparities literature identified a common pattern among middle-aged African Americans that includes high rates of chronic disease along with low rates of psychiatric disorders despite exposure to high levels of cumulative SES risk. The current study was designed to test hypotheses about the developmental precursors to this pattern. Hypotheses were tested with a representative sample of 443 African American youths living in the rural South. Cumulative SES risk and protective processes were assessed at 11-13 years; psychological adjustment was assessed at ages 14-18 years; genotyping at the 5-HTTLPR was conducted at age 16 years; and allostatic load (AL) was assessed at age 19 years. A Latent Profile Analysis identified 5 profiles that evinced distinct patterns of SES risk, AL, and psychological adjustment, with 2 relatively large profiles designated as focal profiles: a physical health vulnerability profile characterized by high SES risk/high AL/low adjustment problems, and a resilient profile characterized by high SES risk/low AL/low adjustment problems. The physical health vulnerability profile mirrored the pattern found in the adult health disparities literature. Multinomial logistic regression analyses indicated that carrying an s allele at the 5-HTTLPR and receiving less peer support distinguished the physical health vulnerability profile from the resilient profile. Protective parenting and planful self-regulation distinguished both focal profiles from the other 3 profiles. The results suggest the public health importance of preventive interventions that enhance coping and reduce the effects of stress across childhood and adolescence. PMID:22709130

  18. Estimated incidence and risk factors of sudden unexpected death

    PubMed Central

    Lin, Feng-Chang; Mehta, Neil; Mounsey, Louisa; Nwosu, Anthony; Pursell, Irion; Chung, Eugene H; Mounsey, J Paul; Simpson, Ross J

    2016-01-01

    Objective In this manuscript, we estimate the incidence and identify risk factors for sudden unexpected death in a socioeconomically and racially diverse population in one county in North Carolina. Estimates of the incidence and risk factors contributing to sudden death vary widely. The Sudden Unexpected Death in North Carolina (SUDDEN) project is a population-based investigation of the incidence and potential causes of sudden death. Methods From 3 March 2013 to 2 March 2014, all out-of-hospital deaths in Wake County, North Carolina, were screened to identify presumed sudden unexpected death among free-living residents between the ages of 18 and 64 years. Death certificate, public and medical records were reviewed and adjudicated to confirm sudden unexpected death cases. Results Following adjudication, 190 sudden unexpected deaths including 122 men and 68 women were identified. Estimated incidence was 32.1 per 100 000 person-years overall: 42.7 among men and 22.4 among women. The majority of victims were white, unmarried men over age 55 years, with unwitnessed deaths at home. Hypertension and dyslipidaemia were common in men and women. African-American women dying from sudden unexpected death were over-represented. Women who were under age 55 years with coronary disease accounted for over half of female participants with coronary artery disease. Conclusions The overall estimated incidence of sudden unexpected death may account for approximately 10% of all deaths classified as ‘natural’. Women have a lower estimated incidence of sudden unexpected death than men. However, we found no major differences in age or comorbidities between men and women. African-Americans and young women with coronary disease are at risk for sudden unexpected death. PMID:27042316

  19. Improved risk estimates for carbon tetrachloride. 1998 annual progress report

    SciTech Connect

    Benson, J.M.; Springer, D.L.; Thrall, K.D.

    1998-06-01

    'The overall purpose of these studies is to improve the scientific basis for assessing the cancer risk associated with human exposure to carbon tetrachloride. Specifically, the toxicokinetics of inhaled carbon tetrachloride is being determined in rats, mice and hamsters. Species differences in the metabolism of carbon tetrachloride by rats, mice and hamsters is being determined in vivo and in vitro using tissues and microsomes from these rodent species and man. Dose-response relationships will be determined in all studies. The information will be used to improve the current physiologically based pharmacokinetic model for carbon tetrachloride. The authors will also determine whether carbon tetrachloride is a hepatocarcinogen only when exposure results in cell damage, cell killing, and regenerative cell proliferation. In combination, the results of these studies will provide the types of information needed to enable a refined risk estimate for carbon tetrachloride under EPA''s new guidelines for cancer risk assessment.'

  20. A comparison of genetic risk score with family history for estimating prostate cancer risk

    PubMed Central

    Helfand, Brian T

    2016-01-01

    Prostate cancer (PCa) testing is recommended by most authoritative groups for high-risk men including those with a family history of the disease. However, family history information is often limited by patient knowledge and clinician intake, and thus, many men are incorrectly assigned to different risk groups. Alternate methods to assess PCa risk are required. In this review, we discuss how genetic variants, referred to as PCa-risk single-nucleotide polymorphisms, can be used to calculate a genetic risk score (GRS). GRS assigns a relatively unique value to all men based on the number of PCa-risk SNPs that an individual carries. This GRS value can provide a more precise estimate of a man's PCa risk. This is particularly relevant in situations when an individual is unaware of his family history. In addition, GRS has utility and can provide a more precise estimate of risk even among men with a positive family history. It can even distinguish risk among relatives with the same degree of family relationships. Taken together, this review serves to provide support for the clinical utility of GRS as an independent test to provide supplemental information to family history. As such, GRS can serve as a platform to help guide-shared decision-making processes regarding the timing and frequency of PCa testing and biopsies. PMID:27004541

  1. Estimating the risks of smoking, air pollution, and passive smoke on acute respiratory conditions

    SciTech Connect

    Ostro, B.D. )

    1989-06-01

    Five years of the annual Health Interview Survey, conducted by the National Center for Health Statistics, are used to estimate the effects of air pollution, smoking, and environmental tobacco smoke on respiratory restrictions in activity for adults, and bed disability for children. After adjusting for several socioeconomic factors, the multiple regression estimates indicate that an independent and statistically significant association exists between these three forms of air pollution and respiratory morbidity. The comparative risks of these exposures are computed and the plausibility of the relative risks is examined by comparing the equivalent doses with actual measurements of exposure taken in the homes of smokers. The results indicate that: (1) smokers will have a 55-75% excess in days with respiratory conditions severe enough to cause reductions in normal activity; (2) a 1 microgram increase in fine particulate matter air pollution is associated with a 3% excess in acute respiratory disease; and (3) a pack-a-day smoker will increase respiratory restricted days for a nonsmoking spouse by 20% and increase the number of bed disability days for young children living in the household by 20%. The results also indicate that the estimates of the effects of secondhand smoking on children are improved when the mother's work status is known and incorporated into the exposure estimate.

  2. Risk estimation based on chromosomal aberrations induced by radiation

    NASA Technical Reports Server (NTRS)

    Durante, M.; Bonassi, S.; George, K.; Cucinotta, F. A.

    2001-01-01

    The presence of a causal association between the frequency of chromosomal aberrations in peripheral blood lymphocytes and the risk of cancer has been substantiated recently by epidemiological studies. Cytogenetic analyses of crew members of the Mir Space Station have shown that a significant increase in the frequency of chromosomal aberrations can be detected after flight, and that such an increase is likely to be attributed to the radiation exposure. The risk of cancer can be estimated directly from the yields of chromosomal aberrations, taking into account some aspects of individual susceptibility and other factors unrelated to radiation. However, the use of an appropriate technique for the collection and analysis of chromosomes and the choice of the structural aberrations to be measured are crucial in providing sound results. Based on the fraction of aberrant lymphocytes detected before and after flight, the relative risk after a long-term Mir mission is estimated to be about 1.2-1.3. The new technique of mFISH can provide useful insights into the quantification of risk on an individual basis.

  3. Toward the Development of Integrative Risk-Adjusted Measures of Quality Using Large Clinical Data Bases: The Case of Anesthesia Services.

    ERIC Educational Resources Information Center

    Fleming, Steven T.

    1992-01-01

    The concept of risk-adjusted measures of quality is discussed, and a methodology is proposed for risk-adjusting and integrating multiple adverse outcomes of anesthesia services into measures for quality assurance and quality improvement programs. Although designed for a new anesthesiology database, the methods should apply to other health…

  4. 48 CFR 215.404-71-3 - Contract type risk and working capital adjustment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) Description. The contract type risk factor focuses on the degree of cost risk accepted by the contractor under... Base (item 20) Profit objective 24. CONTRACT type risk (1) (2) (3) Cost financed Length factor Interest...., cost and performance incentives) that place a high degree of risk on the contractor; (iv) FMS...

  5. 48 CFR 215.404-71-3 - Contract type risk and working capital adjustment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Description. The contract type risk factor focuses on the degree of cost risk accepted by the contractor under... Base (item 20) Profit objective 24. CONTRACT type risk (1) (2) (3) Cost financed Length factor Interest...., cost and performance incentives) that place a high degree of risk on the contractor; (iv) FMS...

  6. 48 CFR 215.404-71-3 - Contract type risk and working capital adjustment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Description. The contract type risk factor focuses on the degree of cost risk accepted by the contractor under... Base (item 20) Profit objective 24. CONTRACT type risk (1) (2) (3) Cost financed Length factor Interest...., cost and performance incentives) that place a high degree of risk on the contractor; (iv) FMS...

  7. Risk cross sections and their application to risk estimation in the galactic cosmic-ray environment

    NASA Technical Reports Server (NTRS)

    Curtis, S. B.; Nealy, J. E.; Wilson, J. W.; Chatterjee, A. (Principal Investigator)

    1995-01-01

    Radiation risk cross sections (i.e. risks per particle fluence) are discussed in the context of estimating the risk of radiation-induced cancer on long-term space flights from the galactic cosmic radiation outside the confines of the earth's magnetic field. Such quantities are useful for handling effects not seen after low-LET radiation. Since appropriate cross-section functions for cancer induction for each particle species are not yet available, the conventional quality factor is used as an approximation to obtain numerical results for risks of excess cancer mortality. Risks are obtained for seven of the most radiosensitive organs as determined by the ICRP [stomach, colon, lung, bone marrow (BFO), bladder, esophagus and breast], beneath 10 g/cm2 aluminum shielding at solar minimum. Spectra are obtained for excess relative risk for each cancer per LET interval by calculating the average fluence-LET spectrum for the organ and converting to risk by multiplying by a factor proportional to R gamma L Q(L) before integrating over L, the unrestricted LET. Here R gamma is the risk coefficient for low-LET radiation (excess relative mortality per Sv) for the particular organ in question. The total risks of excess cancer mortality obtained are 1.3 and 1.1% to female and male crew, respectively, for a 1-year exposure at solar minimum. Uncertainties in these values are estimated to range between factors of 4 and 15 and are dominated by the biological uncertainties in the risk coefficients for low-LET radiation and in the LET (or energy) dependence of the risk cross sections (as approximated by the quality factor). The direct substitution of appropriate risk cross sections will eventually circumvent entirely the need to calculate, measure or use absorbed dose, equivalent dose and quality factor for such a high-energy charged-particle environment.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Seismic Risk Assessment and Loss Estimation for Tbilisi City

    NASA Astrophysics Data System (ADS)

    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.

  10. Risk estimation for fast neutrons with regard to solid cancer.

    PubMed

    Kellerer, A M; Walsh, L

    2001-12-01

    In the absence of epidemiological information on the effects of neutrons, their cancer mortality risk coefficient is currently taken as the product of two low-dose extrapolations: the nominal risk coefficient for photons and the presumed maximum relative biological effectiveness of neutrons. This approach is unnecessary. Since linearity in dose is assumed for neutrons at low to moderate effect levels, the risk coefficient can be derived in terms of the excess risk from epidemiological observations at an intermediate dose of gamma rays and an assumed value, R(1), of the neutron RBE relative to this reference dose of gamma rays. Application of this procedure to the A-bomb data requires accounting for the effect of the neutron dose component, which, according to the current dosimetry system, DS86, amounts on average to 11 mGy in the two cities at a total dose of 1 Gy. With R(1) tentatively set to 20 or 50, it is concluded that the neutrons have caused 18% or 35%, respectively, of the total effect at 1 Gy. The excess relative risk (ERR) for neutrons then lies between 8 per Gy and 16 per Gy. Translating these values into risk coefficients in terms of the effective dose, E, requires accounting for the gamma-ray component produced by the neutron field in the human body, which will require a separate analysis. The risk estimate for neutrons will remain essentially unaffected by the current reassessment of the neutron doses in Hiroshima, because the doses are unlikely to change much at the reference dose of 1 Gy. PMID:11741494

  11. Using risk adjustment approaches in child welfare performance measurement: Applications and insights from health and mental health settings

    PubMed Central

    Raghavan, Ramesh

    2014-01-01

    Federal policymaking in the last decade has dramatically expanded performance measurement within child welfare systems, and states are currently being fiscally penalized for poor performance on defined outcomes. However, in contrast to performance measurement in health settings, current policy holds child welfare systems solely responsible for meeting outcomes, largely without taking into account the effects of factors at the level of the child, and his or her social ecology, that might undermine the performance of child welfare agencies. Appropriate measurement of performance is predicated upon the ability to disentangle individual, as opposed to organizational, determinants of outcomes, which is the goal of risk adjustment methodologies. This review briefly conceptualizes and examines risk adjustment approaches in health and child welfare, suggests approaches to expanding its use to appropriately measure the performance of child welfare agencies, and highlights research gaps that diminish the appropriate use of risk adjustment approaches – and which consequently suggest the need for caution – in policymaking around performance measurement of child welfare agencies. PMID:25253917

  12. Leukemia risk associated with benzene exposure in the pliofilm cohort. II. Risk estimates.

    PubMed

    Paxton, M B; Chinchilli, V M; Brett, S M; Rodricks, J V

    1994-04-01

    The detailed work histories of the individual workers composing the Pliofilm cohort represent a unique resource for estimating the dose-response for leukemia that may follow occupational exposure to benzene. In this paper, we report the results of analyzing the updated Pliofilm cohort using the proportional hazards model, a more sophisticated technique that uses more of the available exposure data than the conditional logistic model used by Rinsky et al. The more rigorously defined exposure estimates derived by Paustenbach et al. are consistent with those of Crump and Allen in giving estimates of the slope of the leukemogenic dose-response that are not as steep as the slope resulting from the exposure estimates of Rinsky et al. We consider estimates of 0.3-0.5 additional leukemia deaths per thousand workers with 45 ppm-years of cumulative benzene exposure to be the best estimates currently available of leukemia risk from occupational exposure to benzene. These risks were estimated in the proportional hazards model when the exposure estimates of Crump and Allen or of Paustenbach et al. were used to derive a cumulative concentration-by-time metric. PMID:8008924

  13. Interpersonal circumplex descriptions of psychosocial risk factors for physical illness: application to hostility, neuroticism, and marital adjustment.

    PubMed

    Smith, Timothy W; Traupman, Emily K; Uchino, Bert N; Berg, Cynthia A

    2010-06-01

    Personality risk factors for physical illness are typically studied individually and apart from risk factors reflecting the social environment, potentially fostering a piecemeal understanding of psychosocial influences on health. Because it can be used to describe both personality and social relationship processes, the interpersonal circumplex (IPC) provides an integrative approach to psychosocial risk. In 301 married couples we examined IPC correlates of 3 risk factor domains: anger, hostility, and aggressiveness; neuroticism; and marital adjustment. Risk factors displayed IPC locations ranging from hostile dominance (e.g., verbal aggressiveness, marital conflict) to hostility (e.g., anger) to hostile submissiveness (e.g., anxiety, depression); protective factors (marital satisfaction and support) reflected warmth or friendliness in the IPC. Similar descriptions were found using self-reports and spouse ratings of IPC dimensions, indicating that interpersonal styles associated with risk factors do not simply reflect common method variance. Findings identify interpersonal processes reflecting low affiliation or high hostility as a common component of risk and indicate distinctions among risk factors along the dominance dimension. PMID:20573134

  14. Spatio-temporal population estimates for risk management

    NASA Astrophysics Data System (ADS)

    Cockings, Samantha; Martin, David; Smith, Alan; Martin, Rebecca

    2013-04-01

    Accurate estimation of population at risk from hazards and effective emergency management of events require not just appropriate spatio-temporal modelling of hazards but also of population. While much recent effort has been focused on improving the modelling and predictions of hazards (both natural and anthropogenic), there has been little parallel advance in the measurement or modelling of population statistics. Different hazard types occur over diverse temporal cycles, are of varying duration and differ significantly in their spatial extent. Even events of the same hazard type, such as flood events, vary markedly in their spatial and temporal characteristics. Conceptually and pragmatically then, population estimates should also be available for similarly varying spatio-temporal scales. Routine population statistics derived from traditional censuses or surveys are usually static representations in both space and time, recording people at their place of usual residence on census/survey night and presenting data for administratively defined areas. Such representations effectively fix the scale of population estimates in both space and time, which is unhelpful for meaningful risk management. Over recent years, the Pop24/7 programme of research, based at the University of Southampton (UK), has developed a framework for spatio-temporal modelling of population, based on gridded population surfaces. Based on a data model which is fully flexible in terms of space and time, the framework allows population estimates to be produced for any time slice relevant to the data contained in the model. It is based around a set of origin and destination centroids, which have capacities, spatial extents and catchment areas, all of which can vary temporally, such as by time of day, day of week, season. A background layer, containing information on features such as transport networks and landuse, provides information on the likelihood of people being in certain places at specific times

  15. Evaluating the Investment Benefit of Multinational Enterprises' International Projects Based on Risk Adjustment: Evidence from China

    ERIC Educational Resources Information Center

    Chen, Chong

    2016-01-01

    This study examines the international risks faced by multinational enterprises to understand their impact on the evaluation of investment projects. Moreover, it establishes a 'three-dimensional' theoretical framework of risk identification to analyse the composition of international risk indicators of multinational enterprises based on the theory…

  16. Estimation of Hail Risk in the UK and Europe

    NASA Astrophysics Data System (ADS)

    Robinson, Eric; Parker, Melanie; Higgs, Stephanie

    2016-04-01

    Observations of hail events in Europe, and the UK especially, are relatively limited. In order to determine hail risk it is therefore necessary to use information other than relying purely on the historical record. One such methodology is to leverage reanalysis data, in this case ERA-Interim, along with a numerical model (WRF) to recreate the past state of the atmosphere. Relevant atmospheric properties can be extracted and used in a regression model to determine hail probability for each day contained within the reanalyses. The results presented here show the results of using a regression model based on convective available potential energy, deep level shear and weather type. Combined these parameters represent the probability of severe thunderstorm, and in turn hail, activity. Once the probability of hail occurring on each day is determined this can be used as the basis of a stochastic catalogue which can be used in the estimation of hail risk.

  17. Global Building Inventory for Earthquake Loss Estimation and Risk Management

    USGS Publications Warehouse

    Jaiswal, Kishor; Wald, David; Porter, Keith

    2010-01-01

    We develop a global database of building inventories using taxonomy of global building types for use in near-real-time post-earthquake loss estimation and pre-earthquake risk analysis, for the U.S. Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER) program. The database is available for public use, subject to peer review, scrutiny, and open enhancement. On a country-by-country level, it contains estimates of the distribution of building types categorized by material, lateral force resisting system, and occupancy type (residential or nonresidential, urban or rural). The database draws on and harmonizes numerous sources: (1) UN statistics, (2) UN Habitat’s demographic and health survey (DHS) database, (3) national housing censuses, (4) the World Housing Encyclopedia and (5) other literature.

  18. Estimation of risks associated with paediatric cochlear implantation.

    PubMed

    Johnston, J Cyne; Smith, Andrée Durieux; Fitzpatrick, Elizabeth; O'Connor, Annette; Angus, Douglas; Benzies, Karen; Schramm, David

    2010-09-01

    The objectives of this study were to estimate the rates of complications associated with paediatric cochlear implantation use: a) at one Canadian cochlear implant (CI) centre, and b) in the published literature. It comprised a retrospective hospital-based chart review and a concurrent review of complications in the published literature. There were 224 children who had undergone surgery from 1994 to June 2007. Results indicate that the rates of complications at the local Canadian paediatric CI centre are not significantly different from the literature rates for all examined complication types. This hospital-based retrospective chart review and review of the literature provide readers with an estimation of the risks to aid in evidence-based decision-making surrounding paediatric cochlear implantation. PMID:19655302

  19. Iterative weighted risk estimation for nonlinear image restoration with analysis priors

    NASA Astrophysics Data System (ADS)

    Ramani, Sathish; Rosen, Jeffrey; Liu, Zhihao; Fessler, Jeffrey A.

    2012-03-01

    Image acquisition systems invariably introduce blur, which necessitates the use of deblurring algorithms for image restoration. Restoration techniques involving regularization require appropriate selection of the regularization parameter that controls the quality of the restored result. We focus on the problem of automatic adjustment of this parameter for nonlinear image restoration using analysis-type regularizers such as total variation (TV). For this purpose, we use two variants of Stein's unbiased risk estimate (SURE), Predicted-SURE and Projected-SURE, that are applicable for parameter selection in inverse problems involving Gaussian noise. These estimates require the Jacobian matrix of the restoration algorithm evaluated with respect to the data. We derive analytical expressions to recursively update the desired Jacobian matrix for a fast variant of the iterative reweighted least-squares restoration algorithm that can accommodate a variety of regularization criteria. Our method can also be used to compute a nonlinear version of the generalized cross-validation (NGCV) measure for parameter tuning. We demonstrate using simulations that Predicted-SURE, Projected-SURE, and NGCV-based adjustment of the regularization parameter yields near-MSE-optimal results for image restoration using TV, an analysis-type 1-regularization, and a smooth convex edge-preserving regularizer.

  20. Pathways of Parenting Style on Adolescents' College Adjustment, Academic Achievement, and Alcohol Risk

    ERIC Educational Resources Information Center

    Kenney, Shannon R.; Lac, Andrew; Hummer, Justin F.; Grimaldi, Elizabeth M.; LaBrie, Joseph W.

    2015-01-01

    This study examined the pathways of parenting style (permissive, authoritarian, and authoritative) to alcohol consumption and consequences through the mediators of college adjustment and academic achievement (grade point average [GPA]). Participants were 289 students from a private, mid-size, West Coast university (mean age 19.01 years, 58.8%…

  1. Health risks in wastewater irrigation: comparing estimates from quantitative microbial risk analyses and epidemiological studies.

    PubMed

    Mara, D D; Sleigh, P A; Blumenthal, U J; Carr, R M

    2007-03-01

    The combination of standard quantitative microbial risk analysis (QMRA) techniques and 10,000-trial Monte Carlo risk simulations was used to estimate the human health risks associated with the use of wastewater for unrestricted and restricted crop irrigation. A risk of rotavirus infection of 10(-2) per person per year (pppy) was used as the reference level of acceptable risk. Using the model scenario of involuntary soil ingestion for restricted irrigation, the risk of rotavirus infection is approximately 10(-2) pppy when the wastewater contains < or =10(6) Escherichia coli per 100ml and when local agricultural practices are highly mechanised. For labour-intensive agriculture the risk of rotavirus infection is approximately 10(-2) pppy when the wastewater contains < or = 10(5) E. coli per 100ml; however, the wastewater quality should be < or = 10(4) E. coli per 100ml when children under 15 are exposed. With the model scenario of lettuce consumption for unrestricted irrigation, the use of wastewaters containing < or =10(4) E. coli per 100ml results in a rotavirus infection risk of approximately 10(-2) pppy; however, again based on epidemiological evidence from Mexico, the current WHO guideline level of < or =1,000 E. coli per 100ml should be retained for root crops eaten raw. PMID:17402278

  2. Positioning resilience for 2015: the role of resistance, incremental adjustment and transformation in disaster risk management policy.

    PubMed

    Matyas, David; Pelling, Mark

    2015-01-01

    Resilience is a ubiquitous term in disaster risk management and is an increasingly prominent concept in early discussions focused on elaborating the post-2015 international policy landscape. Riddled with competing meanings and diverse policy implications, however, it is a concept caught between the abstract and operational. This paper provides a review of the rise to prominence of the concept of resilience and advances an elaboration of the related concepts of resistance, incremental adjustment and transformation. We argue that these concepts can contribute to decision-making by offering three distinct options for risk management policy. In order to deliberately and effectively choose among these options, we suggest that critical reflexivity is a prerequisite, necessitating improved decision-making capacity if varied perspectives (including those of the most vulnerable) are to be involved in the selection of the best approach to risk management. PMID:25494954

  3. Regional glacial isostatic adjustment in Antarctica estimated from GRACE, Enivsat/ICESat and GPS observations (ESA-STSE project REGINA).

    NASA Astrophysics Data System (ADS)

    Klemann, V.; Sasgen, I.; Horwath, M.; Petrie, E. J.; Schoen, N.; Pail, R.; Horvath, A.; Bamber, J. L.; Clarke, P. J.; Konrad, H.; Drinkwater, M. R.

    2014-12-01

    The viscoelastic adjustment of the solid Earth to former glacial loads in Antarctica and the associated gravity-field change and surface displacement is a major uncertainty in determining the mass balance of the ice sheet from satellite gravimetry, and, to a lesser extent, altimetry measurements such as CryoSat-2. On the other hand, measurements of GIA inferred from the geodetic observations provide valuable information on the glacial history and the lithosphere and mantle properties in Antarctica. Here, we present an improved regional GIA estimate based on GRACE, Envisat/ICESat and GPS measurements. Making use of the different sensitivities of the observations to surface-mass and solid Earth processes, we derive an improved GIA field, using an ensemble of viscoelastic response functions to a disc load forcing. The estimated GIA signal is interpreted for recent ice load changes in West Antarctica in the presence of a low-viscous upper mantle, and evaluated for correcting GRACE and CryoSat-2 measurements when determining present-day ice-mass balance in Antarctica. The results are part of the ESA-STSE project REGINA, www.regina-science.eu.

  4. An empirically adjusted approach to reproductive number estimation for stochastic compartmental models: A case study of two Ebola outbreaks.

    PubMed

    Brown, Grant D; Oleson, Jacob J; Porter, Aaron T

    2016-06-01

    The various thresholding quantities grouped under the "Basic Reproductive Number" umbrella are often confused, but represent distinct approaches to estimating epidemic spread potential, and address different modeling needs. Here, we contrast several common reproduction measures applied to stochastic compartmental models, and introduce a new quantity dubbed the "empirically adjusted reproductive number" with several advantages. These include: more complete use of the underlying compartmental dynamics than common alternatives, use as a potential diagnostic tool to detect the presence and causes of intensity process underfitting, and the ability to provide timely feedback on disease spread. Conceptual connections between traditional reproduction measures and our approach are explored, and the behavior of our method is examined under simulation. Two illustrative examples are developed: First, the single location applications of our method are established using data from the 1995 Ebola outbreak in the Democratic Republic of the Congo and a traditional stochastic SEIR model. Second, a spatial formulation of this technique is explored in the context of the ongoing Ebola outbreak in West Africa with particular emphasis on potential use in model selection, diagnosis, and the resulting applications to estimation and prediction. Both analyses are placed in the context of a newly developed spatial analogue of the traditional SEIR modeling approach. PMID:26574727

  5. Survivorship models for estimating the risk of decompression sickness.

    PubMed

    Kumar, K V; Powell, M R

    1994-07-01

    Several approaches have been used for modeling the incidence of decompression sickness (DCS) such as Hill's dose-response and logistic regression. Most of these methods do not include the time-to-onset information in the model. Survival analysis (failure time analysis) is appropriate when the time to onset of an event is of interest. The applicability of survival analysis for modeling the risk of DCS is illustrated by using data obtained from hypobaric chamber exposures simulating extravehicular activities (n = 426). Univariate analysis of incidence-free survival proportions were obtained for Doppler-detectable circulating microbubbles (CMB), symptoms of DCS and test aborts. A log-linear failure time regression model with 360-min half-time tissue ratio (TR) as covariate was constructed, and estimated probabilities for various TR values were calculated. Further regression analysis by including CMB status in this model showed significant improvement (p < 0.05) in the estimation of DCS over the previous model. Since DCS is dependent on the exposure pressure as well as the duration of exposure, we recommend the use of survival analysis for modeling the risk of DCS. PMID:7945136

  6. Assessing changes in socioemotional adjustment across early school transitions-new national scales for children at risk.

    PubMed

    McDermott, Paul A; Watkins, Marley W; Rovine, Michael J; Rikoon, Samuel H

    2013-02-01

    This article reports the development and evidence for validity and application of the Adjustment Scales for Early Transition in Schooling (ASETS). Based on primary analyses of data from the Head Start Impact Study, a nationally representative sample (N=3077) of randomly selected children from low-income households is configured to inform developmental-transitional stability and change in socioemotional adjustment. Longitudinal exploratory and confirmatory factor analysis of the ASETS revealed behavioral dimensions of Aggression, Attention Seeking, Reticence/Withdrawal, Low Energy, and higher-order dimensions of Overactivity and Underactivity. Each dimension was vertically equated through IRT, with Bayesian scoring across 2 years of prekindergarten, kindergarten, and 1st grade. Multilevel modeling provides evidence for concurrent validity, assessment of future risk, and detection of differential growth trajectories across the 4 years of early school transition. PMID:23375175

  7. Risk and Protective Factors for Psychological Adjustment among Low-Income, African American Children

    ERIC Educational Resources Information Center

    Gabalda, Megan K.; Thompson, Martie P.; Kaslow, Nadine J.

    2010-01-01

    This investigation identifies unique risk and protective factors for internalizing and externalizing problems among 8- to 12-year-old, low-income, African American children and tests cumulative risk and protective models. A total of 152 mother-child dyads complete questionnaires. Receipt of food stamps, mother's distress, and child maltreatment…

  8. Time-to-Compromise Model for Cyber Risk Reduction Estimation

    SciTech Connect

    Miles A. McQueen; Wayne F. Boyer; Mark A. Flynn; George A. Beitel

    2005-09-01

    We propose a new model for estimating the time to compromise a system component that is visible to an attacker. The model provides an estimate of the expected value of the time-to-compromise as a function of known and visible vulnerabilities, and attacker skill level. The time-to-compromise random process model is a composite of three subprocesses associated with attacker actions aimed at the exploitation of vulnerabilities. In a case study, the model was used to aid in a risk reduction estimate between a baseline Supervisory Control and Data Acquisition (SCADA) system and the baseline system enhanced through a specific set of control system security remedial actions. For our case study, the total number of system vulnerabilities was reduced by 86% but the dominant attack path was through a component where the number of vulnerabilities was reduced by only 42% and the time-to-compromise of that component was increased by only 13% to 30% depending on attacker skill level.

  9. Why and when is ethnic harassment a risk for immigrant adolescents' school adjustment? understanding the processes and conditions.

    PubMed

    Bayram Özdemir, Sevgi; Stattin, Håkan

    2014-08-01

    Ethnically harassed immigrant youth are at risk for experiencing a wide range of school adjustment problems. However, it is still unclear why and under what conditions experiencing ethnic harassment leads to school adjustment difficulties. To address this limitation in the literature, we examined two important questions. First, we investigated whether self-esteem and/or depressive symptoms would mediate the associations between ethnic harassment and poor school adjustment among immigrant youth. Second, we examined whether immigrant youths' perception of school context would play a buffering role in the pathways between ethnic harassment and school adjustment difficulties. The sample (n = 330; M age = 14.07, SD = .90; 49% girls at T1) was drawn from a longitudinal study in Sweden. The results revealed that experiencing ethnic harassment led to a decrease in immigrant youths' self-esteem over time, and that youths' expectations of academic failure increased. Further, youths' relationships with their teachers and their perceptions of school democracy moderated the mediation processes. Specifically, when youth had poor relationships with their teachers or perceived their school context as less democratic, being exposed to ethnic harassment led to a decrease in their self-esteem. In turn, they reported low school satisfaction and perceived themselves as being unsuccessful in school. Such indirect effects were not observed when youth had high positive relationships with their teachers or perceived their school as offering a democratic environment. These findings highlight the importance of understanding underlying processes and conditions in the examination of the effects of ethnic devaluation experiences in order to reach a more comprehensive understanding of immigrant youths' school adjustment. PMID:24132501

  10. Moving towards a new paradigm for global flood risk estimation

    NASA Astrophysics Data System (ADS)

    Troy, Tara J.; Devineni, Naresh; Lima, Carlos; Lall, Upmanu

    2013-04-01

    model is implemented at a finer resolution (<=1km) in order to more accurately model streamflow under flood conditions and estimate inundation. This approach allows for efficient computational simulation of the hydrology when not under potential for flooding with high-resolution flood wave modeling when there is flooding potential. We demonstrate the results of this flood risk estimation system for the Ohio River basin in the United States, a large river basin that is historically prone to flooding, with the intention of using it to do global flood risk assessment.

  11. Risk-Adjusted Impact of Administrative Costs on the Distribution of Terminal Wealth for Long-Term Investment

    PubMed Central

    Guillén, Montserrat; Jarner, Søren Fiig; Pérez-Marín, Ana M.

    2014-01-01

    The impact of administrative costs on the distribution of terminal wealth is approximated using a simple formula applicable to many investment situations. We show that the reduction in median returns attributable to administrative fees is usually at least twice the amount of the administrative costs charged for most investment funds, when considering a risk-adjustment correction over a reasonably long-term time horizon. The example we present covers a number of standard cases and can be applied to passive investments, mutual funds, and hedge funds. Our results show investors the potential losses they face in performance due to administrative costs. PMID:25180200

  12. Including pathogen risk in life cycle assessment of wastewater management. 1. Estimating the burden of disease associated with pathogens.

    PubMed

    Harder, Robin; Heimersson, Sara; Svanström, Magdalena; Peters, Gregory M

    2014-08-19

    The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2-9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28,600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series. PMID:25058492

  13. Parent birds assess nest predation risk and adjust their reproductive strategies

    USGS Publications Warehouse

    Fontaine, J.J.; Martin, T.E.

    2006-01-01

    Avian life history theory has long assumed that nest predation plays a minor role in shaping reproductive strategies. Yet, this assumption remains conspicuously untested by broad experiments that alter environmental risk of nest predation, despite the fact that nest predation is a major source of reproductive failure. Here, we examined whether parents can assess experimentally reduced nest predation risk and alter their reproductive strategies. We experimentally reduced nest predation risk and show that in safer environments parents increased investment in young through increased egg size, clutch mass, and the rate they fed nestlings. Parents also increased investment in female condition by increasing the rates that males fed incubating females at the nest, and decreasing the time that females spent incubating. These results demonstrate that birds can assess nest predation risk at large and that nest predation plays a key role in the expression of avian reproductive strategies. ?? 2006 Blackwell Publishing Ltd/CNRS.

  14. 41 CFR 102-80.50 - Are Federal agencies responsible for identifying/estimating risks and for appropriate risk...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 80-SAFETY AND ENVIRONMENTAL MANAGEMENT Safety and 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...

  15. 41 CFR 102-80.50 - Are Federal agencies responsible for identifying/estimating risks and for appropriate risk...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (Continued) FEDERAL MANAGEMENT REGULATION REAL PROPERTY 80-SAFETY AND ENVIRONMENTAL MANAGEMENT Safety and 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...

  16. Estimated Insulin Sensitivity and Cardiovascular Disease Risk Factors in Adolescents with and without Type 1 Diabetes

    PubMed Central

    Specht, Brian J; Wadwa, R Paul; Snell-Bergeon, Janet K; Nadeau, Kristen J; Bishop, Franziska K; Maahs, David M.

    2012-01-01

    Objective To test the hypothesis that cardiovascular disease (CVD) risk factors are similar in adolescents with and without diabetes (T1D) in the most insulin sensitive (IS) tertile and CVD risk factors are more atherogenic with decreasing IS in adolescents with T1D. Study design Adolescents with IS T1D (n=292; age=15.4±2.1 years; duration=8.8±3.0 years, HbA1c=8.9±1.6%) and non-diabetic (non-DM) controls (n=89; age=15.4±2.1 years) was estimated using the model: logeIS=4.64725 – 0.02032(waist, cm) – 0.09779(HbA1c, %) – 0.00235(triglycerides, mg/dl). CVD risk factors (blood pressure, fasting total, LDL and HDL-cholesterol, hs-CRP, and BMI Z-score) were compared between all non-DM adolescents and those with T1D in the most IS tertile, and then examined for a linear trend by IS tertile in adolescents with T1D, adjusted for sex, race/ethnicity and Tanner Stage. Results Estimated IS was significantly lower in adolescents with T1D compared with those without (T1D=7.8±2.4, non-DM=11.5±2.9; p<0.0001). CVD risk factors were similar for non-DM compared with the adolescents with most IS T1D, except for higher HDL-c and DBP in adolescents with T1D (p<0.05). Among adolescents with T1D, all CVD risk factors except for HDL-c, were more atherogenic across decreasing IS tertiles in linear regression analysis (p<0.05). Conclusion Adolescents with T1D who are the most IS have similar CVD risk factors compared with non-DM adolescents. CVD risk factors are inversely associated with adolescents with IS T1D. IS may be an important therapeutic target for reducing CVD risk factors in adolescents with T1D. PMID:22921593

  17. Declining bioavailability and inappropriate estimation of risk of persistent compounds

    SciTech Connect

    Kelsey, J.W.; Alexander, M.

    1997-03-01

    Earthworms (Eisenia foetida) assimilated decreasing amounts of atrazine, phenanthrene, and naphthalene that had been incubated for increasing periods of time in sterile soil. The amount of atrazine and phenanthrene removed from soil by mild extractants also decreased with time. The declines in bioavailability of the three compounds to earthworms and of naphthalene to bacteria were not reflected by analysis involving vigorous methods of solvent extraction; similar results for bioavailability of phenanthrene and 4-nitrophenol to bacteria were obtained in a previous study conducted at this laboratory. The authors suggest that regulations based on vigorous extractions for the analyses of persistent organic pollutants in soil do not appropriately estimate exposure or risk to susceptible populations.

  18. Social risk and protective factors for African American children's academic achievement and adjustment during the transition to middle school.

    PubMed

    Burchinal, Margaret R; Roberts, Joanne E; Zeisel, Susan A; Rowley, Stephanie J

    2008-01-01

    The transition to middle school is often marked by decreased academic achievement and increased emotional stress, and African American children exposed to social risk may be especially vulnerable during this transition. To identify mediators and protective factors, the authors related severity and timing of risk exposure to academic achievement and adjustment between 4th and 6th grade in 74 African American children. Longitudinal analyses indicated that severity more than timing of risk exposure was negatively related to all outcomes and that language skills mediated the pathway from risk for most outcomes. Transition to middle school was related to lower math scores and to more externalizing problems when children experienced higher levels of social risk. Language skills and parenting served as protective factors, whereas expectations of racial discrimination was a vulnerability factor. Results imply that promoting parenting and, especially, language skills, and decreasing expectations of racial discrimination provide pathways to academic success for African American children during the transition from elementary to middle school, especially those exposed to adversity. PMID:18194027

  19. Exponentially weighted moving average charts to compare observed and expected values for monitoring risk-adjusted hospital indicators.

    PubMed

    Cook, D A; Coory, M; Webster, R A

    2011-06-01

    OBJECTIVE To introduce a new type of risk-adjusted (RA) exponentially weighted moving average (EWMA) chart and to compare it to a commonly used type of variable life adjusted display chart for analysis of patient outcomes. DATA Routine inpatient data on mortality following admission for acute myocardial infarction, from all public and private hospitals in Queensland, Australia. METHODS The RA-EWMA plots the EWMA of the observed and predicted values. Predicted values were obtained from a logistic regression model for all hospitals in Queensland. The EWMA of the predicted values is a moving centre line, reflecting current patient case mix at a particular hospital. Thresholds around this moving centre line provide a scale by which to assess the importance of trends in the EWMA of the observed values. RESULTS The RA-EWMA chart can be designed to have equivalent performance, in terms of average run lengths, as variable life adjusted display chart. The advantages of the RA-EWMA are that it communicates information about the current level of an indicator in a direct and understandable way, and it explicitly displays information about the current patient case mix. Also, because it is not reset, the RA-EWMA is a more natural chart to use in health, where it is exceedingly rare to stop or dramatically and abruptly alter a process of care. CONCLUSION The RA-EWMA chart is a direct and intuitive way to display information about an indicator while accounting for differences in case mix. PMID:21209145

  20. Estimation of Tsunami Risk for the Caribbean Coast

    NASA Astrophysics Data System (ADS)

    Zahibo, N.

    2004-05-01

    The tsunami problem for the coast of the Caribbean basin is discussed. Briefly the historical data of tsunami in the Caribbean Sea are presented. Numerical simulation of potential tsunamis in the Caribbean Sea is performed in the framework of the nonlinear-shallow theory. The tsunami wave height distribution along the Caribbean Coast is computed. These results are used to estimate the far-field tsunami potential of various coastal locations in the Caribbean Sea. In fact, five zones with tsunami low risk are selected basing on prognostic computations, they are: the bay "Golfo de Batabano" and the coast of province "Ciego de Avila" in Cuba, the Nicaraguan Coast (between Bluefields and Puerto Cabezas), the border between Mexico and Belize, the bay "Golfo de Venezuela" in Venezuela. The analysis of historical data confirms that there was no tsunami in the selected zones. Also, the wave attenuation in the Caribbean Sea is investigated; in fact, wave amplitude decreases in an order if the tsunami source is located on the distance up to 1000 km from the coastal location. Both factors wave attenuation and wave height distribution should be taken into account in the planned warning system for the Caribbean Sea. Specially the problem of tsunami risk for Lesser Antilles including Guadeloupe is discussed.

  1. Regression Equations for Estimation of Annual Peak-Streamflow Frequency for Undeveloped Watersheds in Texas Using an L-moment-Based, PRESS-Minimized, Residual-Adjusted Approach

    USGS Publications Warehouse

    Asquith, William H.; Roussel, Meghan C.

    2009-01-01

    Annual peak-streamflow frequency estimates are needed for flood-plain management; for objective assessment of flood risk; for cost-effective design of dams, levees, and other flood-control structures; and for design of roads, bridges, and culverts. Annual peak-streamflow frequency represents the peak streamflow for nine recurrence intervals of 2, 5, 10, 25, 50, 100, 200, 250, and 500 years. Common methods for estimation of peak-streamflow frequency for ungaged or unmonitored watersheds are regression equations for each recurrence interval developed for one or more regions; such regional equations are the subject of this report. The method is based on analysis of annual peak-streamflow data from U.S. Geological Survey streamflow-gaging stations (stations). Beginning in 2007, the U.S. Geological Survey, in cooperation with the Texas Department of Transportation and in partnership with Texas Tech University, began a 3-year investigation concerning the development of regional equations to estimate annual peak-streamflow frequency for undeveloped watersheds in Texas. The investigation focuses primarily on 638 stations with 8 or more years of data from undeveloped watersheds and other criteria. The general approach is explicitly limited to the use of L-moment statistics, which are used in conjunction with a technique of multi-linear regression referred to as PRESS minimization. The approach used to develop the regional equations, which was refined during the investigation, is referred to as the 'L-moment-based, PRESS-minimized, residual-adjusted approach'. For the approach, seven unique distributions are fit to the sample L-moments of the data for each of 638 stations and trimmed means of the seven results of the distributions for each recurrence interval are used to define the station specific, peak-streamflow frequency. As a first iteration of regression, nine weighted-least-squares, PRESS-minimized, multi-linear regression equations are computed using the watershed

  2. How to Estimate Epidemic Risk from Incomplete Contact Diaries Data?

    PubMed

    Mastrandrea, Rossana; Barrat, Alain

    2016-06-01

    Social interactions shape the patterns of spreading processes in a population. Techniques such as diaries or proximity sensors allow to collect data about encounters and to build networks of contacts between individuals. The contact networks obtained from these different techniques are however quantitatively different. Here, we first show how these discrepancies affect the prediction of the epidemic risk when these data are fed to numerical models of epidemic spread: low participation rate, under-reporting of contacts and overestimation of contact durations in contact diaries with respect to sensor data determine indeed important differences in the outcomes of the corresponding simulations with for instance an enhanced sensitivity to initial conditions. Most importantly, we investigate if and how information gathered from contact diaries can be used in such simulations in order to yield an accurate description of the epidemic risk, assuming that data from sensors represent the ground truth. The contact networks built from contact sensors and diaries present indeed several structural similarities: this suggests the possibility to construct, using only the contact diary network information, a surrogate contact network such that simulations using this surrogate network give the same estimation of the epidemic risk as simulations using the contact sensor network. We present and compare several methods to build such surrogate data, and show that it is indeed possible to obtain a good agreement between the outcomes of simulations using surrogate and sensor data, as long as the contact diary information is complemented by publicly available data describing the heterogeneity of the durations of human contacts. PMID:27341027

  3. How to Estimate Epidemic Risk from Incomplete Contact Diaries Data?

    PubMed Central

    Mastrandrea, Rossana; Barrat, Alain

    2016-01-01

    Social interactions shape the patterns of spreading processes in a population. Techniques such as diaries or proximity sensors allow to collect data about encounters and to build networks of contacts between individuals. The contact networks obtained from these different techniques are however quantitatively different. Here, we first show how these discrepancies affect the prediction of the epidemic risk when these data are fed to numerical models of epidemic spread: low participation rate, under-reporting of contacts and overestimation of contact durations in contact diaries with respect to sensor data determine indeed important differences in the outcomes of the corresponding simulations with for instance an enhanced sensitivity to initial conditions. Most importantly, we investigate if and how information gathered from contact diaries can be used in such simulations in order to yield an accurate description of the epidemic risk, assuming that data from sensors represent the ground truth. The contact networks built from contact sensors and diaries present indeed several structural similarities: this suggests the possibility to construct, using only the contact diary network information, a surrogate contact network such that simulations using this surrogate network give the same estimation of the epidemic risk as simulations using the contact sensor network. We present and compare several methods to build such surrogate data, and show that it is indeed possible to obtain a good agreement between the outcomes of simulations using surrogate and sensor data, as long as the contact diary information is complemented by publicly available data describing the heterogeneity of the durations of human contacts. PMID:27341027

  4. Gambling disorder: estimated prevalence rates and risk factors in Macao.

    PubMed

    Wu, Anise M S; Lai, Mark H C; Tong, Kwok-Kit

    2014-12-01

    An excessive, problematic gambling pattern has been regarded as a mental disorder in the Diagnostic and Statistical Manual for Mental Disorders (DSM) for more than 3 decades (American Psychiatric Association [APA], 1980). In this study, its latest prevalence in Macao (one of very few cities with legalized gambling in China and the Far East) was estimated with 2 major changes in the diagnostic criteria, suggested by the 5th edition of DSM (APA, 2013): (a) removing the "Illegal Act" criterion, and (b) lowering the threshold for diagnosis. A random, representative sample of 1,018 Macao residents was surveyed with a phone poll design in January 2013. After the 2 changes were adopted, the present study showed that the estimated prevalence rate of gambling disorder was 2.1% of the Macao adult population. Moreover, the present findings also provided empirical support to the application of these 2 recommended changes when assessing symptoms of gambling disorder among Chinese community adults. Personal risk factors of gambling disorder, namely being male, having low education, a preference for casino gambling, as well as high materialism, were identified. PMID:25134026

  5. Risk adjustment for health care financing in chronic disease: What are we missing by failing to account for disease severity?

    PubMed Central

    Omachi, Theodore A.; Gregorich, Steven E.; Eisner, Mark D.; Penaloza, Renee A.; Tolstykh, Irina V.; Yelin, Edward H.; Iribarren, Carlos; Dudley, R. Adams; Blanc, Paul D.

    2013-01-01

    BACKGROUND Adjustment for differing risks among patients is usually incorporated into newer payment approaches, and current risk models rely on age, gender, and diagnosis codes. It is unknown the extent to which controlling additionally for disease severity improves cost prediction. Failure to adjust for within-disease variation may create incentives to avoid sicker patients. We address this issue among patients with chronic obstructive pulmonary disease (COPD). METHODS Cost and clinical data were collected prospectively from 1,202 COPD patients at Kaiser Permanente. Baseline analysis included age, gender, and diagnosis codes (using the Diagnostic Cost Group Relative Risk Score [RRS]) in a general linear model predicting total medical costs in the following year. We determined whether adding COPD severity measures—FEV1, 6 minute walk test, dyspnea score, body-mass index, and BODE Index (composite of the other four measures)—improved predictions. Separately, we examined household income as a cost predictor. RESULTS Mean costs were $12,334/year. Controlling for RRS, each ½ standard deviation worsening in COPD severity factor was associated with $629 to $1,135 in increased annual costs (all p<0.01). The lowest stratum of FEV1 (<30% normal) predicted $4,098 (95%CI $576–$8,773) additional costs. Household income predicted excess costs when added to the baseline model (p=0.038), but this became non-significant when also incorporating BODE Index. CONCLUSIONS Disease severity measures explain significant cost variations beyond current risk models, and adding them to such models appears important to fairly compensate organizations that accept responsibility for sicker COPD patients. Appropriately controlling for disease severity also accounts for costs otherwise associated with lower socioeconomic status. PMID:23703646

  6. Impact of urine concentration adjustment method on associations between urine metals and estimated glomerular filtration rates (eGFR) in adolescents

    SciTech Connect

    Weaver, Virginia M.; Vargas, Gonzalo García; Silbergeld, Ellen K.; Rothenberg, Stephen J.; Fadrowski, Jeffrey J.; Rubio-Andrade, Marisela; Parsons, Patrick J.; Steuerwald, Amy J.; and others

    2014-07-15

    Positive associations between urine toxicant levels and measures of glomerular filtration rate (GFR) have been reported recently in a range of populations. The explanation for these associations, in a direction opposite that of traditional nephrotoxicity, is uncertain. Variation in associations by urine concentration adjustment approach has also been observed. Associations of urine cadmium, thallium and uranium in models of serum creatinine- and cystatin-C-based estimated GFR (eGFR) were examined using multiple linear regression in a cross-sectional study of adolescents residing near a lead smelter complex. Urine concentration adjustment approaches compared included urine creatinine, urine osmolality and no adjustment. Median age, blood lead and urine cadmium, thallium and uranium were 13.9 years, 4.0 μg/dL, 0.22, 0.27 and 0.04 g/g creatinine, respectively, in 512 adolescents. Urine cadmium and thallium were positively associated with serum creatinine-based eGFR only when urine creatinine was used to adjust for urine concentration (β coefficient=3.1 mL/min/1.73 m{sup 2}; 95% confidence interval=1.4, 4.8 per each doubling of urine cadmium). Weaker positive associations, also only with urine creatinine adjustment, were observed between these metals and serum cystatin-C-based eGFR and between urine uranium and serum creatinine-based eGFR. Additional research using non-creatinine-based methods of adjustment for urine concentration is necessary. - Highlights: • Positive associations between urine metals and creatinine-based eGFR are unexpected. • Optimal approach to urine concentration adjustment for urine biomarkers uncertain. • We compared urine concentration adjustment methods. • Positive associations observed only with urine creatinine adjustment. • Additional research using non-creatinine-based methods of adjustment needed.

  7. Maternal Adjustment and Infant Outcome in Medically Defined High-Risk Pregnancy.

    ERIC Educational Resources Information Center

    Levy-Shiff, Rachel; Lerman, Maya; Har-Even, Dov; Hod, Moshe

    2002-01-01

    Explored relation of biological and psychosocial risk factors to infant development among pregnant women who had pregestational diabetes, gestational diabetes, or were nondiabetic. Found that infants of diabetic mothers scored lower on the Bayley Scales at 1 year and revealed fewer positive and more negative behaviors than infants of nondiabetic…

  8. Socioenvironmental Risk and Adjustment in Latino Youth: The Mediating Effects of Family Processes and Social Competence

    ERIC Educational Resources Information Center

    Prelow, Hazel M.; Loukas, Alexandra; Jordan-Green, Lisa

    2007-01-01

    The direct and mediated effects of socioenvironmental risk on internalizing and externalizing problems among Latino youth aged 10-14 were examined using prospective analyses. Participants in this study were 464 Latino mother and child dyads surveyed as part of the "Welfare, Children & Families: A Three City Study." It was hypothesized that…

  9. Soil-ecological risks for soil degradation estimation

    NASA Astrophysics Data System (ADS)

    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

  10. ESTIMATED SIL LEVELS AND RISK COMPARISONS FOR RELIEF VALVES AS A FUNCTION OF TIME-IN-SERVICE

    SciTech Connect

    Harris, S.

    2012-03-26

    Risk-based inspection methods enable estimation of the probability of spring-operated relief valves failing on demand at the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. The paper illustrates an approach based on application of the Frechet and Weibull distributions to SRS and Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD) proof test results. The methodology enables the estimation of ANSI/ISA-84.00.01 Safety Integrity Levels (SILs) as well as the potential change in SIL level due to modification of the maintenance schedule. Current SRS practices are reviewed and recommendations are made for extending inspection intervals. The paper compares risk-based inspection with specific SILs as maintenance intervals are adjusted. Groups of valves are identified in which maintenance times can be extended as well as different groups in which an increased safety margin may be needed.

  11. Childhood CT scans and cancer risk: impact of predisposing factors for cancer on the risk estimates.

    PubMed

    Journy, N; Roué, T; Cardis, E; Le Pointe, H Ducou; Brisse, H; Chateil, J-F; Laurier, D; Bernier, M-O

    2016-03-01

    To investigate the role of cancer predisposing factors (PFs) on the associations between paediatric computed tomography (CT) scan exposures and subsequent risk of central nervous system (CNS) tumours and leukaemia. A cohort of children who underwent a CT scan in 2000-2010 in 23 French radiology departments was linked with the national childhood cancers registry and national vital status registry; information on PFs was retrieved through hospital discharge databases. In children without PF, hazard ratios of 1.07 (95% CI 0.99-1.10) for CNS tumours (15 cases) and 1.16 (95% CI 0.77-1.27) for leukaemia (12 cases) were estimated for each 10 mGy increment in CT x-rays organ doses. These estimates were similar to those obtained in the whole cohort. In children with PFs, no positive dose-risk association was observed, possibly related to earlier non-cancer mortality in this group. Our results suggest a modifying effect of PFs on CT-related cancer risks, but need to be confirmed by longer follow-up and other studies. PMID:26878249

  12. Potential risk of using General Estimates System: bicycle safety.

    PubMed

    Kweon, Young-Jun; Lee, Joyoung

    2010-11-01

    Beneficial effects of bicycle helmet use have been reported mostly based on medical or survey data collected from hospitals. This study was to examine the validity of the United States General Estimates System (GES) database familiar to many transportation professionals for a beneficial effect of helmet use in reducing the severity of injury to bicyclists and found potential risk of erroneous conclusions that can be drawn by a narrowly focused study when the GES database is used. Although the focus of the study was on bicycle helmet use, its findings regarding potential risk might be true for any type of traffic safety study using the GES data. A partial proportional odds model reflecting intrinsic ordering of injury severity was mainly used. About 16,000 bicycle-involved traffic crash records occurring in 2003 through 2008 in the United States were extracted from the GES database. Using the 2003-2008 GES data, a beneficial effect of helmet use was found in 2007, yet a detrimental effect in 2004 and no effect in 2003, 2005, 2006, and 2008, which are contrary to the past findings from medical or hospital survey data. It was speculated that these mixed results might be attributable to a possible lack of representation of the GES data for bicycle-involved traffic crashes, which may be supported by the findings, such as the average helmet use rates at the time of the crashes varying from 12% in 2004 to 38% in 2008. This suggests that the GES data may not be a reliable source for studying narrowly focused issues such as the effect of helmet use. A considerable fluctuation over years in basic statistical values (e.g., average) of variables of interest (e.g., helmet use) may be an indication of a possible lack of representation of the GES data. In such a case, caution should be exercised in interpreting and generalizing analysis results. PMID:20728621

  13. The Impact of Perceived Frailty on Surgeons’ Estimates of Surgical Risk

    PubMed Central

    Ferguson, Mark K.; Farnan, Jeanne; Hemmerich, Josh A.; Slawinski, Kris; Acevedo, Julissa; Small, Stephen

    2015-01-01

    Background Physicians are only moderately accurate in estimating surgical risk based on clinical vignettes. We assessed the impact of perceived frailty by measuring the influence of a short video of a standardized patient on surgical risk estimates. Methods Thoracic surgeons and cardiothoracic trainees estimated the risk of major complications for lobectomy based on clinical vignettes of varied risk categories (low, average, high). After each vignette, subjects viewed a randomly selected video of a standardized patient exhibiting either vigorous or frail behavior, then re-estimated risk. Subjects were asked to rate 5 vignettes paired with 5 different standardized patients. Results Seventy-one physicians participated. Initial risk estimates varied according to the vignette risk category: low, 15.2 ± 11.2% risk; average, 23.7 ± 16.1%; high, 37.3 ± 18.9%; p<0.001 by ANOVA. Concordant information in vignettes and videos moderately altered estimates (high risk vignette, frail video: 10.6 ± 27.5% increase in estimate, p=0.006; low risk vignette, vigorous video: 14.5 ± 45.0% decrease, p=0.009). Discordant findings influenced risk estimates more substantially (high risk vignette, vigorous video: 21.2 ± 23.5% decrease in second risk estimate, p<0.001; low risk vignette, frail video: 151.9 ± 209.8% increase, p<0.001). Conclusions Surgeons differentiated relative risk of lobectomy based on clinical vignettes. The effect of viewing videos was small when vignettes and videos were concordant; the effect was more substantial when vignettes and videos were discordant. The information will be helpful in training future surgeons in frailty recognition and risk estimation. PMID:24932570

  14. Estimating urban flood risk - uncertainty in design criteria

    NASA Astrophysics Data System (ADS)

    Newby, M.; Franks, S. W.; White, C. J.

    2015-06-01

    The design of urban stormwater infrastructure is generally performed assuming that climate is static. For engineering practitioners, stormwater infrastructure is designed using a peak flow method, such as the Rational Method as outlined in the Australian Rainfall and Runoff (AR&R) guidelines and estimates of design rainfall intensities. Changes to Australian rainfall intensity design criteria have been made through updated releases of the AR&R77, AR&R87 and the recent 2013 AR&R Intensity Frequency Distributions (IFDs). The primary focus of this study is to compare the three IFD sets from 51 locations Australia wide. Since the release of the AR&R77 IFDs, the duration and number of locations for rainfall data has increased and techniques for data analysis have changed. Updated terminology coinciding with the 2013 IFD release has also resulted in a practical change to the design rainfall. For example, infrastructure that is designed for a 1 : 5 year ARI correlates with an 18.13% AEP, however for practical purposes, hydraulic guidelines have been updated with the more intuitive 20% AEP. The evaluation of design rainfall variation across Australia has indicated that the changes are dependent upon location, recurrence interval and rainfall duration. The changes to design rainfall IFDs are due to the application of differing data analysis techniques, the length and number of data sets and the change in terminology from ARI to AEP. Such changes mean that developed infrastructure has been designed to a range of different design criteria indicating the likely inadequacy of earlier developments to the current estimates of flood risk. In many cases, the under-design of infrastructure is greater than the expected impact of increased rainfall intensity under climate change scenarios.

  15. Estimated effect of ventilation and filtration on chronic health risks in U.S. offices, schools, and retail stores.

    PubMed

    Chan, W R; Parthasarathy, S; Fisk, W J; McKone, T E

    2016-04-01

    We assessed the chronic health risks from inhalation exposure to volatile organic compounds (VOCs) and particulate matter (PM2.5) in U.S. offices, schools, grocery, and other retail stores and evaluated how chronic health risks were affected by changes in ventilation rates and air filtration efficiency. Representative concentrations of VOCs and PM2.5 were obtained from available data. Using a mass balance model, changes in exposure to VOCs and PM2.5 were predicted if ventilation rate were to increase or decrease by a factor of two, and if higher efficiency air filters were used. Indoor concentrations were compared to health guidelines to estimate percentage exceedances. The estimated chronic health risks associated with VOC and PM2.5 exposures in these buildings were low relative to the risks from exposures in homes. Chronic health risks were driven primarily by exposures to PM2.5 that were evaluated using disease incidence of mortality, chronic bronchitis, and non-fatal stroke. The leading cancer risk factor was exposure to formaldehyde. Using disability-adjusted life years (DALYs) to account for both cancer and non-cancer effects, results suggest that increasing ventilation alone is ineffective at reducing chronic health burdens. Other strategies, such as pollutant source control and the use of particle filtration, should also be considered. PMID:25639183

  16. RADON EXPOSURE ASSESSMENT AND DOSIMETRY APPLIED TO EPIDEMIOLOGY AND RISK ESTIMATION

    EPA Science Inventory

    Epidemiological studies of underground miners provide the primary basis for radon risk estimates for indoor exposures as well as mine exposures. A major source of uncertainty in these risk estimates is the uncertainty in radon progeny exposure estimates for the miners. In addit...

  17. The HeartMate II Risk Score: An Adjusted Score for Evaluation of All Continuous-Flow Left Ventricular Assist Devices.

    PubMed

    Cowger, Jennifer Ann; Castle, Lindsay; Aaronson, Keith David; Slaughter, Mark S; Moainie, Sina; Walsh, Mary; Salerno, Christopher

    2016-01-01

    The aim of this study was to evaluate the performance of an adjusted HeartMate II risk score (HMRS) in Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS; n = 9,733) and in HeartWare Ventricular Assist Device (HVAD) bridge to transplant (BTT) trial patients (n = 360). Interagency Registry for Mechanically Assisted Circulatory Support data were used to calculate an adjusted HMRS, omitting center volume, for all patients on continuous-flow left ventricular assist device (LVAD) support. Ninety day mortality was then evaluated in INTERMACS and HVAD-BTT patients. Four risk groups were identified based on INTERMACS patient-adjusted HMRS: very low (<5%, 90 day mortality; score <0.20), low (5-10%, 90 day mortality; score 0.20-1.97), medium (10-20%, 90 day mortality; score 1.98-4.48), and high risk (>20%, 90 day mortality; score >4.48). Within INTERMACS, there were significant differences in survival between all-adjusted HMRS risk groups (p < 0.001 in pairwise comparisons). Controlling for known mortality correlates, the adjusted HMRS mortality hazard ratio was 1.19 (1.25-1.23) per unit HMRS increase. The HVAD cohort was a low-risk cohort with 90 day survivals for very low-, low-, and medium-risk patients of 100%, 97 ± 1.1%, and 90 ± 3.6%, respectively (p = 0.007). Patients in the very low- and low-risk group had significantly improved survival compared with medium-risk patients, respectively (both p < 0.05). The adjusted HMRS appropriately risk stratified a large cohort of INTERMACS patients and was predictive of survival in HeartWare-supported patients. PMID:26955002

  18. Willingness to pay for a quality-adjusted life year: an evaluation of attitudes towards risk and preferences

    PubMed Central

    2014-01-01

    Background This paper examines the Willingness to Pay (WTP) for a quality-adjusted life year (QALY) expressed by people who attended the healthcare system as well as the association of attitude towards risk and other personal characteristics with their response. Methods Health-state preferences, measured by EuroQol (EQ-5D-3L), were combined with WTP for recovering a perfect health state. WTP was assessed using close-ended, iterative bidding, contingent valuation method. Data on demographic and socioeconomic characteristics, as well as usage of health services by the subjects were collected. The attitude towards risk was evaluated by collecting risky behaviors data, by the subject’s self-evaluation, and through lottery games. Results Six hundred and sixty two subjects participated and 449 stated a utility inferior to 1. WTP/QALY ratios varied significantly when payments with personal money (mean €10,119; median €673) or through taxes (mean €28,187; median €915) were suggested. Family income, area income, higher education level, greater use of healthcare services, and the number of co-inhabitants were associated with greater WTP/QALY ratios. Age and female gender were associated with lower WTP/QALY ratios. Risk inclination was independently associated with a greater WTP/QALY when “out of pocket” payments were suggested. Clear discrepancies were demonstrated between linearity and neutrality towards risk assumptions and experimental results. Conclusions WTP/QALY ratios vary noticeably based on demographic and socioeconomic characteristics of the subject, but also on their attitude towards risk. Knowing the expression of preferences by patients from this outcome measurement can be of interest for health service planning. PMID:24989615

  19. Impact of urine concentration adjustment method on associations between urine metals and estimated glomerular filtration rates (eGFR) in adolescents☆

    PubMed Central

    Weaver, Virginia M.; Vargas, Gonzalo García; Silbergeld, Ellen K.; Rothenberg, Stephen J.; Fadrowski, Jeffrey J.; Rubio-Andrade, Marisela; Parsons, Patrick J.; Steuerwald, Amy J.; Navas-Acien, Ana; Guallar, Eliseo

    2014-01-01

    Positive associations between urine toxicant levels and measures of glomerular filtration rate (GFR) have been reported recently in a range of populations. The explanation for these associations, in a direction opposite that of traditional nephrotoxicity, is uncertain. Variation in associations by urine concentration adjustment approach has also been observed. Associations of urine cadmium, thallium and uranium in models of serum creatinine- and cystatin-C-based estimated GFR (eGFR) were examined using multiple linear regression in a cross-sectional study of adolescents residing near a lead smelter complex. Urine concentration adjustment approaches compared included urine creatinine, urine osmolality and no adjustment. Median age, blood lead and urine cadmium, thallium and uranium were 13.9 years, 4.0 μg/dL, 0.22, 0.27 and 0.04 g/g creatinine, respectively, in 512 adolescents. Urine cadmium and thallium were positively associated with serum creatinine-based eGFR only when urine creatinine was used to adjust for urine concentration (β coefficient=3.1 mL/min/1.73 m2; 95% confidence interval=1.4, 4.8 per each doubling of urine cadmium). Weaker positive associations, also only with urine creatinine adjustment, were observed between these metals and serum cystatin-C-based eGFR and between urine uranium and serum creatinine-based eGFR. Additional research using non-creatinine-based methods of adjustment for urine concentration is necessary. PMID:24815335

  20. Risk and protection factors in the peer context: how do other children contribute to the psychosocial adjustment of the adolescent?

    PubMed

    Véronneau, Marie-Hélène; Trempe, Sophie-Caroline; Paiva, Alexandra Oliveira

    2014-03-01

    As children become adolescents, peers assume greater importance in their lives. Peer experiences can either help them thrive or negatively affect their psychosocial adjustment. In this review article definitions for the types of peer experiences are provided followed by an overview of common psychosocial issues encountered by adolescents. Past research that has pointed to risk and protection factors that emerge from peer experiences during adolescence and the role of peer influences in the context of current issues relevant to adolescent education are discussed. Research suggests that friendships with deviant peers, involvement in bullying and the experience of rejection from the overall peer group are related to adjustment problems, whereas friendships with prosocial and academically oriented peers and social acceptance in the peer group are related to healthy development. Friendship quality, popularity among peers, and involvement in friendship cliques cannot be clearly categorized as either positive or negative influences, because they interact with other factors in shaping the development of adolescents. The promotion of social skills and positive youth leadership as an integral part of the student's learning process in school is recommended. PMID:24714885

  1. Adjustments of ejaculation rates in response to risk of sperm competition in a fish, the bitterling (Rhodeus sericeus).

    PubMed Central

    Candolin, Ulrika; Reynolds, John D

    2002-01-01

    Game theory models of sperm competition predict that within species, males should increase their sperm expenditure when they have one competitor, but decrease expenditure with increasing numbers of competitors. So far, there have been few tests or support for this prediction. Here, we show that males of a freshwater fish, the European bitterling, Rhodeus sericeus, do indeed adjust their ejaculation rate to the number of male competitors by first increasing and then decreasing their ejaculation rates as the number of competitors increases. However, this occurred only under restricted conditions. Specifically, the prediction was upheld as long as no female had deposited eggs in the live mussels that are used as spawning sites. After one or more females had spawned, males did not decrease their ejaculation rates with the number of competitors, but instead they became more aggressive. This indicates that decreased ejaculation rate and increased aggression are alternative responses to increased risk of sperm competition. PMID:12184824

  2. State Estimates of Adolescent Cigarette Use and Perceptions of Risk of Smoking: 2012 and 2013

    MedlinePlus

    ... 2015 STATE ESTIMATES OF ADOLESCENT CIGARETTE USE AND PERCEPTIONS OF RISK OF SMOKING: 2012 AND 2013 AUTHORS ... with an inverse association between use and risk perceptions (i.e., the prevalence of use is lower ...

  3. Risk Estimates From an Online Risk Calculator Are More Believable and Recalled Better When Expressed as Integers

    PubMed Central

    Zikmund-Fisher, Brian J; Waters, Erika A; Gavaruzzi, Teresa; Fagerlin, Angela

    2011-01-01

    Background Online risk calculators offer different levels of precision in their risk estimates. People interpret numbers in varying ways depending on how they are presented, and we do not know how the number of decimal places displayed might influence perceptions of risk estimates. Objective The objective of our study was to determine whether precision (ie, number of decimals) in risk estimates offered by an online risk calculator influences users’ ratings of (1) how believable the estimate is, (2) risk magnitude (ie, how large or small the risk feels to them), and (3) how well they can recall the risk estimate after a brief delay. Methods We developed two mock risk calculator websites that offered hypothetical percentage estimates of participants’ lifetime risk of kidney cancer. Participants were randomly assigned to a condition where the risk estimate value rose with increasing precision (2, 2.1, 2.13, 2.133) or the risk estimate value fell with increasing precision (2, 1.9, 1.87, 1.867). Within each group, participants were randomly assigned one of the four numbers as their first risk estimate, and later received one of the remaining three as a comparison. Results Participants who completed the experiment (N = 3422) were a demographically diverse online sample, approximately representative of the US adult population on age, gender, and race. Participants whose risk estimates had no decimal places gave the highest ratings of believability (F 3,3384 = 2.94, P = .03) and the lowest ratings of risk magnitude (F 3,3384 = 4.70, P = .003). Compared to estimates with decimal places, integer estimates were judged as highly believable by 7%–10% more participants (χ2 3 =17.8, P < .001). When comparing two risk estimates with different levels of precision, large majorities of participants reported that the numbers seemed equivalent across all measures. Both exact and approximate recall were highest for estimates with zero decimals. Odds ratios (OR) for correct

  4. Does Visceral Fat Estimated by Dual-Energy X-ray Absorptiometry Independently Predict Cardiometabolic Risks in Adults?

    PubMed Central

    Sasai, Hiroyuki; Brychta, Robert J.; Wood, Rachel P.; Rothney, Megan P.; Zhao, Xiongce; Skarulis, Monica C.; Chen, Kong Y.

    2015-01-01

    Background: Abdominal visceral fat, typically measured by computer tomography (CT) or magnetic resonance imaging (MRI), has been shown to correlate with cardiometabolic risks. The purpose of this study was to examine whether a newly developed and validated visceral fat measurement from dual-energy X-ray absorptiometry (DXA) provides added predictive value to the cross-sectional differences of cardiometabolic parameters beyond the traditional anthropometric and DXA adiposity parameters. Method: A heterogeneous cohort of 194 adults (81 males and 113 females) with a BMI of 19 to 54 kg/m2 participated in this cross-sectional study. Body composition was measured with a DXA densitometer. Visceral fat was then computed with a proprietary algorithm. Insulin sensitivity index (SI, measured by intravenous glucose tolerance test), blood pressures, and lipid profiles, and peak oxygen uptake were also measured as cardiometabolic risk parameters. Results: DXA-estimated visceral fat mass was associated with HDL cholesterol (regression coefficient [β] = −5.15, P < .01, adjusted R2 = .21), triglyceride (β = 26.01, P < .01, adjusted R2 = .14), and peak oxygen uptake (β = −3.15, P < .01, adjusted R2 = .57) after adjusting for age, gender, and ethnicity. A subanalysis stratifying gender-specific BMI tertiles showed visceral fat, together with ethnicity, was independently associated with SI in overweight men and moderately obese women (second tertile). Conclusions: Without requiring additional CT or MRI-based measurements, visceral fat detected by DXA might offer certain advantages over the traditional DXA adiposity parameters as means of assessing cardiometabolic risks. PMID:25802470

  5. Cancer risk estimation caused by radiation exposure during endovascular procedure

    NASA Astrophysics Data System (ADS)

    Kang, Y. H.; Cho, J. H.; Yun, W. S.; Park, K. H.; Kim, H. G.; Kwon, S. M.

    2014-05-01

    The objective of this study was to identify the radiation exposure dose of patients, as well as staff caused by fluoroscopy for C-arm-assisted vascular surgical operation and to estimate carcinogenic risk due to such exposure dose. The study was conducted in 71 patients (53 men and 18 women) who had undergone vascular surgical intervention at the division of vascular surgery in the University Hospital from November of 2011 to April of 2012. It had used a mobile C-arm device and calculated the radiation exposure dose of patient (dose-area product, DAP). Effective dose was measured by attaching optically stimulated luminescence on the radiation protectors of staff who participates in the surgery to measure the radiation exposure dose of staff during the vascular surgical operation. From the study results, DAP value of patients was 308.7 Gy cm2 in average, and the maximum value was 3085 Gy cm2. When converted to the effective dose, the resulted mean was 6.2 m Gy and the maximum effective dose was 61.7 milliSievert (mSv). The effective dose of staff was 3.85 mSv; while the radiation technician was 1.04 mSv, the nurse was 1.31 mSv. All cancer incidences of operator are corresponding to 2355 persons per 100,000 persons, which deemed 1 of 42 persons is likely to have all cancer incidences. In conclusion, the vascular surgeons should keep the radiation protection for patient, staff, and all participants in the intervention in mind as supervisor of fluoroscopy while trying to understand the effects by radiation by themselves to prevent invisible danger during the intervention and to minimize the harm.

  6. Estimating Risk of Alcohol Dependence Using Alcohol Screening Scores*

    PubMed Central

    Rubinsky, Anna D.; Kivlahan, Daniel R.; Volk, Robert J.; Maynard, Charles; Bradley, Katharine A.

    2010-01-01

    Brief alcohol counseling interventions can reduce alcohol consumption and related morbidity among non-dependent risky drinkers, but more intensive alcohol treatment is recommended for persons with alcohol dependence. This study evaluated whether scores on common alcohol screening tests could identify patients likely to have current alcohol dependence so that more appropriate follow-up assessment and/or intervention could be offered. This cross-sectional study used secondary data from 392 male and 927 female adult family medicine outpatients (1993–1994). Likelihood ratios were used to empirically identify and evaluate ranges of scores of the AUDIT, the AUDIT-C, two single-item questions about frequency of binge drinking, and the CAGE questionnaire for detecting DSM-IV past-year alcohol dependence. Based on the prevalence of past-year alcohol dependence in this sample (men: 12.2%; women: 5.8%), zones of the AUDIT and AUDIT-C identified wide variability in the post-screening risk of alcohol dependence in men and women, even among those who screened positive for alcohol misuse. Among men, AUDIT zones 5–10, 11–14 and 15–40 were associated with post-screening probabilities of past-year alcohol dependence ranging from 18–87%, and AUDIT-C zones 5–6, 7–9 and 10–12 were associated with probabilities ranging from 22–75%. Among women, AUDIT zones 3–4, 5–8, 9–12 and 13–40 were associated with post-screening probabilities of past-year alcohol dependence ranging from 6–94%, and AUDIT-C zones 3, 4–6, 7–9 and 10–12 were associated with probabilities ranging from 9–88%. AUDIT or AUDIT-C scores could be used to estimate the probability of past-year alcohol dependence among patients who screen positive for alcohol misuse and inform clinical decision-making. PMID:20042299

  7. The 2006 William Feinberg lecture: shifting the paradigm from stroke to global vascular risk estimation.

    PubMed

    Sacco, Ralph L

    2007-06-01

    By the year 2010, it is estimated that 18.1 million people worldwide will die annually because of cardiovascular diseases and stroke. "Global vascular risk" more broadly includes the multiple overlapping disease silos of stroke, myocardial infarction, peripheral arterial disease, and vascular death. Estimation of global vascular risk requires consideration of a variety of variables including demographics, environmental behaviors, and risk factors. Data from multiple studies suggest continuous linear relationships between the physiological vascular risk modulators of blood pressure, lipids, and blood glucose rather than treating these conditions as categorical risk factors. Constellations of risk factors may be more relevant than individual categorical components. Exciting work with novel risk factors may also have predictive value in estimates of global vascular risk. Advances in imaging have led to the measurement of subclinical conditions such as carotid intima-media thickness and subclinical brain conditions such as white matter hyperintensities and silent infarcts. These subclinical measurements may be intermediate stages in the transition from asymptomatic to symptomatic vascular events, appear to be associated with the fundamental vascular risk factors, and represent opportunities to more precisely quantitate disease progression. The expansion of studies in molecular epidemiology and detection of genetic markers underlying vascular risks also promises to extend our precision of global vascular risk estimation. Global vascular risk estimation will require quantitative methods that bundle these multi-dimensional data into more precise estimates of future risk. The power of genetic information coupled with data on demographics, risk-inducing behaviors, vascular risk modulators, biomarkers, and measures of subclinical conditions should provide the most realistic approximation of an individual's future global vascular risk. The ultimate public health benefit

  8. Ryegrass cv. Lema and guava cv. Paluma biomonitoring suitability for estimating nutritional contamination risks under seasonal climate in Southeastern Brazil.

    PubMed

    Bulbovas, Patricia; Camargo, Carla Z S; Domingos, Marisa

    2015-08-01

    The risks posed by nutrient deposition due to air pollution on ecosystems and their respective services to human beings can be appropriately estimated by bioindicator plants when they are well acclimated to the study region environmental conditions. This assumption encouraged us to comparatively evaluate the accumulation potential of ryegrass cv. Lema and guava cv. Paluma macro and micronutrients. We also indicated the most appropriate species for biomonitoring nutrient contamination risks in tropical areas of Southeastern Brazil, which are characterized by marked dry and wet seasons and complex mixtures of air pollutants from different sources (industries, vehicle traffic and agriculture). The study was conducted in 14 sites with different neighboring land uses, within the Metropolitan Region of Campinas, central-eastern region of São Paulo State. The exposure experiments with ryegrass and guava were consecutively repeated 40 (28 days each) and 12 (84 days each) times, respectively, from Oct/2010 to Sept/2013. Macro and micronutrients were analyzed and background concentrations and enrichment ratios (ER) were estimated to classify the contamination risk within the study region. Significantly higher ER suggested that ryegrass were the most appropriate accumulator species for N, S, Mg, Fe, Mn, Cu and Zn deposition and guava for K, Ca, P and B deposition. Based on these biomonitoring adjustments, we concluded that the nutrient deposition was spatially homogeneous in the study area, but clear seasonality in the contamination risk by nutritional inputs was evidenced. Significantly higher contamination risk by S, Fe, K and B occurred during the dry season and enhanced contamination risk by Mn, Cu and Zn were highlighted during the wet season. Distinctly high contamination risk was estimated for S, Fe and Mn in several exposure experiments. PMID:25938695

  9. Patient mobility for cardiac problems: a risk-adjusted analysis in Italy

    PubMed Central

    2013-01-01

    researchers can benefit from risk stratification data, which provides more elements for correct comparisons and interventions. In the context of patient mobility, the present study is a step in that direction. PMID:23399540

  10. Application of quantitative estimates of fecal hemoglobin concentration for risk prediction of colorectal neoplasia

    PubMed Central

    Liao, Chao-Sheng; Lin, Yu-Min; Chang, Hung-Chuen; Chen, Yu-Hung; Chong, Lee-Won; Chen, Chun-Hao; Lin, Yueh-Shih; Yang, Kuo-Ching; Shih, Chia-Hui

    2013-01-01

    AIM: To determine the role of the fecal immunochemical test (FIT), used to evaluate fecal hemoglobin concentration, in the prediction of histological grade and risk of colorectal tumors. METHODS: We enrolled 17881 individuals who attended the two-step colorectal cancer screening program in a single hospital between January 2010 and October 2011. Colonoscopy was recommended to the participants with an FIT of ≥ 12 ngHb/mL buffer. We classified colorectal lesions as cancer (C), advanced adenoma (AA), adenoma (A), and others (O) by their colonoscopic and histological findings. Multiple linear regression analysis adjusted for age and gender was used to determine the association between the FIT results and colorectal tumor grade. The risk of adenomatous neoplasia was estimated by calculating the positive predictive values for different FIT concentrations. RESULTS: The positive rate of the FIT was 10.9% (1948/17881). The attendance rate for colonoscopy was 63.1% (1229/1948). The number of false positive results was 23. Of these 1229 cases, the numbers of O, A, AA, and C were 759, 221, 201, and 48, respectively. Regression analysis revealed a positive association between histological grade and FIT concentration (β = 0.088, P < 0.01). A significant log-linear relationship was found between the concentration and positive predictive value of the FIT for predicting colorectal tumors (R2 > 0.95, P < 0.001). CONCLUSION: Higher FIT concentrations are associated with more advanced histological grades. Risk prediction for colorectal neoplasia based on individual FIT concentrations is significant and may help to improve the performance of screening programs. PMID:24363529

  11. Latent-failure risk estimates for computer control

    NASA Technical Reports Server (NTRS)

    Dunn, William R.; Folsom, Rolfe A.; Green, Owen R.

    1991-01-01

    It is shown that critical computer controls employing unmonitored safety circuits are unsafe. Analysis supporting this result leads to two additional, important conclusions: (1) annual maintenance checks of safety circuit function do not, as widely believed, eliminate latent failure risk; (2) safety risk remains even if multiple, series-connected protection circuits are employed. Finally, it is shown analytically that latent failure risk is eliminated when continuous monitoring is employed.

  12. State Estimates of Adolescent Marijuana Use and Perceptions of Risk of Harm from Marijuana Use: 2013 and 2014

    MedlinePlus

    ... 2014 estimates to 2012–2013 estimates). However, youth perceptions of great risk of harm from monthly marijuana ... change. State Estimates of Adolescent Marijuana Use and Perceptions of Risk of Harm From Marijuana Use: 2013 ...

  13. Indoor radon and lung cancer. Estimating the risks.

    PubMed Central

    Samet, J. M.

    1992-01-01

    Radon is ubiquitous in indoor environments. Epidemiologic studies of underground miners with exposure to radon and experimental evidence have established that radon causes lung cancer. The finding that this naturally occurring carcinogen is present in the air of homes and other buildings has raised concern about the lung cancer risk to the general population from radon. I review current approaches for assessing the risk of indoor radon, emphasizing the extrapolation of the risks for miners to the general population. Although uncertainties are inherent in this risk assessment, the present evidence warrants identifying homes that have unacceptably high concentrations. PMID:1734594

  14. Rodents in open space adjust their behavioral response to the different risk levels during barn-owl attack

    PubMed Central

    Edut, Shahaf; Eilam, David

    2003-01-01

    Background Previous studies have revealed that the response of prey species to predatory risk comprised either freezing (when the prey remained immobile), or fleeing (when it ran frantically in order to remove itself from the vicinity of the predator). Other studies, however, have suggested that the prey will adjust its behavior to risk level. The present study was designed to follow the attacks of a barn owl (Tyto alba) on common spiny mice (Acomys cahirinus) and social voles (Microtus socialis guntherei), in order to reveal the correspondence between the behavior of the owl, the risk level at each phase of the owl's attack, and the defensive behavior of the rodents. Results Spiny mice dramatically increased the traveled distance upon the appearance of the owl, and kept moving during its attack while taking long trajectories of locomotion. Defensive response in voles dichotomized: in some voles traveled distance dropped when the owl appeared, reaching zero during its attack. In other voles, traveled distance dramatically increased once the owl appeared and further increased under its attack. These defensive responses developed by gradual tuning of normal locomotor behavior in accordance with the level of risk. Conclusions The phenotypic difference in defensive behavior between voles and spiny mice probably stems from their different habitats and motor capacities. Agility and running capacity, together with a relatively sheltered natural habitat, make fleeing the most appropriate response for spiny mice during owl attack. Clumsiness and relatively limited motor capacities, together with an open natural habitat, account for the dichotomy to freezing or fleeing in voles. Thus, the apparent species-specific anti-predator response in spiny mice and voles is based on species-specific normal locomotor behavior, which depends on the species-specific ecology and motor capacity, and behaviors like defensive attack or escape jump that are specific to life threat. The latter

  15. ESTIMATION OF EMISSION ADJUSTMENTS FROM THE APPLICATION OF FOUR-DIMENSIONAL DATA ASSIMILATION TO PHOTOCHEMICAL AIR QUALITY MODELING. (R826372)

    EPA Science Inventory

    Four-dimensional data assimilation applied to photochemical air quality modeling is used to suggest adjustments to the emissions inventory of the Atlanta, Georgia metropolitan area. In this approach, a three-dimensional air quality model, coupled with direct sensitivity analys...

  16. Estimating the risk of type-2 diabetes using obese-years in a contemporary population of the Framingham Study

    PubMed Central

    Abdullah, Asnawi; Amin, Fauzi Ali; Hanum, Farida; Stoelwinder, Johannes; Tanamas, Stephanie; Wolf, Rory; Wong, Evelyn; Peeters, Anna

    2016-01-01

    Background We have recently demonstrated that an obese-years construct is a better predictor of the risk of diabetes than the severity of body weight alone. However, these risk estimates were derived from a population cohort study initiated in 1948 that might not apply to the current population. Objective To validate an obese-years construct in estimating the risk of type-2 diabetes in a more contemporary cohort study. Design A total of 5,132 participants of the Framingham Offspring Study, initiated in 1972, were followed up for 45 years. Body mass index (BMI) above 29 kg/m2 was multiplied by the number of years lived with obesity at that BMI to define the number of obese-years. Time-dependent Cox regression was used to explore the association. Results The risk of type-2 diabetes increased significantly with increase in obese-years. Adjusted hazard ratios increased by 6% (95% CI: 5–7%) per additional 10 points of obese-years. This ratio was observed to be similar in both men and women, but was 4% higher in current smokers than in never/ex-smokers. The Akaike Information Criterion confirmed that the Cox regression model with the obese-years construct was a stronger predictor of the risk of diabetes than a model including either BMI or the duration of obesity alone. Conclusions In a contemporary cohort population, it was confirmed that the obese-years construct is strongly associated with an increased risk of type-2 diabetes. This suggests that both severity and the duration of obesity should be considered in future estimations of the burden of disease associated with obesity. PMID:27369220

  17. CCSI Risk Estimation: An Application of Expert Elicitation

    SciTech Connect

    Engel, David W.; Dalton, Angela C.

    2012-10-01

    The Carbon Capture Simulation Initiative (CCSI) is a multi-laboratory simulation-driven effort to develop carbon capture technologies with the goal of accelerating commercialization and adoption in the near future. One of the key CCSI technical challenges is representing and quantifying the inherent uncertainty and risks associated with developing, testing, and deploying the technology in simulated and real operational settings. To address this challenge, the CCSI Element 7 team developed a holistic risk analysis and decision-making framework. The purpose of this report is to document the CCSI Element 7 structured systematic expert elicitation to identify additional risk factors. We review the significance of and established approaches to expert elicitation, describe the CCSI risk elicitation plan and implementation strategies, and conclude by discussing the next steps and highlighting the contribution of risk elicitation toward the achievement of the overarching CCSI objectives.

  18. High cost pool or high cost groups-How to handle high(est) cost cases in a risk adjustment mechanism?

    PubMed

    Schillo, Sonja; Lux, Gerald; Wasem, Juergen; Buchner, Florian

    2016-02-01

    Competitive social health insurance systems (at least) in Western Europe have implemented systems of morbidity based risk adjustment to set a level playing field for insurers. However, many high cost insured still are heavily underfunded despite risk adjustment, leaving incentives for risk selection. In most of these health care systems, there is an ongoing debate about how to deal with such underpaid high cost cases. This study develops four distinct concepts by adding variables to risk adjustment or by setting up a high cost pool for underpaid insured besides the risk adjustment system. Their features, incentives and distributional effects are discussed. With a data set of 6 million insured, performance is demonstrated for Germany. All models achieve a substantial improvement in model fit, measured in terms of R(2) as well as CPM. As the results of the various models are different in different dimensions, the trade-offs that have to be dealt with and should be addressed, when implementing a model to reduce underfunding of high cost cases. PMID:26806676

  19. Improvement of radar quantitative precipitation estimation based on real-time adjustments to Z-R relationships and inverse distance weighting correction schemes

    NASA Astrophysics Data System (ADS)

    Wang, Gaili; Liu, Liping; Ding, Yuanyuan

    2012-05-01

    The errors in radar quantitative precipitation estimations consist not only of systematic biases caused by random noises but also spatially nonuniform biases in radar rainfall at individual rain-gauge stations. In this study, a real-time adjustment to the radar reflectivity-rainfall rates ( Z-R) relationship scheme and the gauge-corrected, radar-based, estimation scheme with inverse distance weighting interpolation was developed. Based on the characteristics of the two schemes, the two-step correction technique of radar quantitative precipitation estimation is proposed. To minimize the errors between radar quantitative precipitation estimations and rain gauge observations, a real-time adjustment to the Z-R relationship scheme is used to remove systematic bias on the time-domain. The gauge-corrected, radar-based, estimation scheme is then used to eliminate non-uniform errors in space. Based on radar data and rain gauge observations near the Huaihe River, the two-step correction technique was evaluated using two heavy-precipitation events. The results show that the proposed scheme improved not only in the underestimation of rainfall but also reduced the root-mean-square error and the mean relative error of radar-rain gauge pairs.

  20. Significance of model credibility in estimating climate projection distributions for regional hydroclimatological risk assessments

    USGS Publications Warehouse

    Brekke, L.D.; Dettinger, M.D.; Maurer, E.P.; Anderson, M.

    2008-01-01

    Ensembles of historical climate simulations and climate projections from the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset were investigated to determine how model credibility affects apparent relative scenario likelihoods in regional risk assessments. Methods were developed and applied in a Northern California case study. An ensemble of 59 twentieth century climate simulations from 17 WCRP CMIP3 models was analyzed to evaluate relative model credibility associated with a 75-member projection ensemble from the same 17 models. Credibility was assessed based on how models realistically reproduced selected statistics of historical climate relevant to California climatology. Metrics of this credibility were used to derive relative model weights leading to weight-threshold culling of models contributing to the projection ensemble. Density functions were then estimated for two projected quantities (temperature and precipitation), with and without considering credibility-based ensemble reductions. An analysis for Northern California showed that, while some models seem more capable at recreating limited aspects twentieth century climate, the overall tendency is for comparable model performance when several credibility measures are combined. Use of these metrics to decide which models to include in density function development led to local adjustments to function shapes, but led to limited affect on breadth and central tendency, which were found to be more influenced by 'completeness' of the original ensemble in terms of models and emissions pathways. ?? 2007 Springer Science+Business Media B.V.

  1. Comparing an estimate of seabirds at risk to a mortality estimate from the November 2004 Terra Nova FPSO oil spill.

    PubMed

    Wilhelm, Sabina I; Robertson, Gregory J; Ryan, Pierre C; Schneider, David C

    2007-05-01

    On 21 November 2004, about 1000 barrels of crude oil were accidentally released from the Terra Nova FPSO (floating production, storage and offloading) onto the Grand Banks, approximately 340 km east-southeast of St. John's, Newfoundland. We estimated the number of vulnerable seabirds (murres (Uria spp.) and dovekies (Alle alle)) at risk from this incident by multiplying observed densities of seabirds with the total area covered by the slick, estimated at 793 km(2). A mean density of 3.46 murres/km(2) and 1.07 dovekies/km(2) on the sea surface was recorded during vessel-based surveys on 28 and 29 November 2004, with a mean density of 6.90 murres/km(2) and 13.43 dovekies/km(2) combining those on the sea and in flight. We calculated a mean of 9858 murres and dovekies were at risk of being oiled, with estimates ranging from 3593 to 16,122 depending on what portion of birds in flight were assumed to be at risk. A mortality model based on spill volume was derived independently of the risk model, and estimated that 4688 (CI 95%: 1905-12,480) birds were killed during this incident. A low mortality estimate based strictly on spill volume would be expected for this incident, which occurred in an area of relatively high seabird densities. Given that the risk and mortality estimates are statistically indistinguishable, we estimate that on the order of 10,000 birds were killed by the Terra Nova spill. PMID:17328926

  2. Job Exposure Matrix (JEM) derived estimates of life-time occupational pesticide exposure and the risk of Parkinson’s Disease

    PubMed Central

    Liew, Zeyan; Wang, Anthony; Bronstein, Jeff; Ritz, Beate

    2013-01-01

    Studies that report an association between Parkinson’s disease (PD) and occupational pesticide exposure often use self-reported exposure and none adjust for concomitant ambient pesticide exposure. For a population-based case-control study of PD conducted in California’s heavily agricultural region we developed a comprehensive Job Exposure Matrix (JEM) to assess occupational exposure to pesticides. Relying on 357 incident cases and 750 population controls enrolled between 2001 to 2011 we estimated more than a two-fold risk increase for PD among men classified as highly occupationally exposed. We also observed an exposure-response pattern and farming tasks with direct and intense pesticide exposures such as spraying and handling of pesticides resulted in greater risks than indirect by-stander exposures. Results did not change after adjustment for ambient pesticide exposure. We provide further evidence that occupational pesticide exposure increases the risk of PD. PMID:24499252

  3. The Effectiveness of Functional Family Therapy in Reducing Adolescent Mental Health Risk and Family Adjustment Difficulties in an Irish Context.

    PubMed

    Hartnett, Dan; Carr, Alan; Sexton, Thomas

    2016-06-01

    To evaluate the effectiveness of Functional Family Therapy (FFT) 42 cases were randomized to FFT and 55 to a waiting-list control group. Minimization procedures controlled the effects of potentially confounding baseline variables. Cases were treated by a team of five therapists who implemented FFT with a moderate degree of fidelity. Rates of clinical recovery were significantly higher in the FFT group than in the control group. Compared to the comparison group, parents in the FFT group reported significantly greater improvement in adolescent problems on the Strengths and Difficulties Questionnaire (SDQ) and both parents and adolescents reported improvements in family adjustment on the Systemic Clinical Outcomes and Routine Evaluation (SCORE). In addition, 93% of youth and families in the treatment condition completed FFT. Improvements shown immediately after treatment were sustained at 3-month follow-up. Results provide a current demonstration of FFT's effectiveness for youth with behavior problems in community-based settings, expand our understanding of the range of positive outcomes of FFT to include mental health risk and family-defined problem severity and impact, and suggests that it is an effective intervention when implemented in an Irish context. PMID:26542420

  4. Pressure and performance: buffering capacity and the cyclical impact of accreditation inspections on risk-adjusted mortality.

    PubMed

    Towers, Tyler J; Clark, Jonathan

    2014-01-01

    The Joint Commission's move toward unannounced site visits in 2006 clearly underscores its goal to ensure more consistent compliance with its standards among accredited hospitals between site visits. As Joint Commission standards are intended to inform a host of practices associated with preventing adverse patient outcomes, and accreditation is intended to signal a satisfactory level of adoption of these practices, there should be no significant fluctuation in patient outcomes if hospital compliance remains sufficiently consistent before, during, and after an accreditation site visit, ceteris paribus. However, prior research on the implementation of practices in healthcare organizations (especially those practices related to quality improvement) points to the likelihood of inconsistency in the use of such practices, even after they have been "adopted." This inconsistency may emerge from shifts in manager attention patterns that may be driven by (1) resource constraints that preclude managers from dedicating consistent and perpetual attention to any given program or initiative and (2) accreditation pressures that are predictably cyclical even when site visits are, technically, unannounced. If these shifts in organizational attention patterns are sufficiently salient, we might expect to see patient outcomes ebb and flow with accreditation site visits. In this study, we explore this possibility by examining monthly patterns in risk-adjusted mortality rates around accreditation site visits. As shifts in organizational attention may be linked to resource constraints, we also explore the role of slack resources in shielding healthcare organizations from the ebbs and flows of external pressures, a capability we term buffering capacity. PMID:25647951

  5. Children's Positive Adjustment to First Grade in Risk-Filled Communities: A Case Study of the Role of School Ecologies in South Africa and Finland

    ERIC Educational Resources Information Center

    Kumpulainen, Kristiina; Theron, Linda; Kahl, Carlien; Bezuidenhout, Carla; Mikkola, Anna; Salmi, Saara; Khumalo, Tumi; Uusitalo-Malmivaara, Lotta

    2016-01-01

    This article presents a comparative case study on the ways in which children's school ecologies facilitate their adjusting positively to first grade in risk-filled contexts in South Africa and Finland. The insights of two children (one South African, one Finnish) from socio-economically disadvantaged communities, their teachers, parents and…

  6. Estimating seroprevalence of vaccine-preventable infections: is it worth standardizing the serological outcomes to adjust for different assays and laboratories?

    PubMed

    Kafatos, G; Andrews, N; McConway, K J; Anastassopoulou, C; Barbara, C; De Ory, F; Johansen, K; Mossong, J; Prosenc, K; Vranckx, R; Nardone, A; Pebody, R; Farrington, P

    2015-08-01

    The aim of the European Sero-Epidemiology Network 2 (ESEN2) project was to estimate age-specific seroprevalence for a number of vaccine-preventable diseases in Europe. To achieve this serosurveys were collected by 22 national laboratories. To adjust for a variety of laboratory methods and assays, all quantitative results were transformed to a reference laboratory's units and were then classified as positive or negative to obtain age-specific seroprevalence. The aim of this study was to assess the value of standardization by comparing the crude and standardized seroprevalence estimates. Seroprevalence was estimated for measles, mumps, rubella, diphtheria, varicella zoster and hepatitis A virus (HAV) and compared before and after serological results had been standardized. The results showed that if no such adjustment had taken place, seroprevalence would have differed by an average of 3·2% (95% bootstrap interval 2·9-3·6) although this percentage varied substantially by antigen. These differences were as high as 16% for some serosurveys (HAV) which means that standardization could have a considerable impact on seroprevalence estimates and should be considered when comparing serosurveys performed in different laboratories using different assay methods. PMID:25420586

  7. Biomechanical Risk Estimates for Mild Traumatic Brain Injury

    PubMed Central

    Funk, J. R.; Duma, S. M.; Manoogian, S. J.; Rowson, S.

    2007-01-01

    The objective of this study was to characterize the risk of mild traumatic brain injury (MTBI) in living humans based on a large set of head impact data taken from American football players at the collegiate level. Real-time head accelerations were recorded from helmet-mounted accelerometers designed to stay in contact with the player’s head. Over 27,000 head impacts were recorded, including four impacts resulting in MTBI. Parametric risk curves were developed by normalizing MTBI incidence data by head impact exposure data. An important finding of this research is that living humans, at least in the setting of collegiate football, sustain much more significant head impacts without apparent injury than previously thought. The following preliminary nominal injury assessment reference values associated with a 10% risk of MTBI are proposed: a peak linear head acceleration of 165 g, a HIC of 400, and a peak angular head acceleration of 9000 rad/s2. PMID:18184501

  8. Probabilistic methodology for estimating radiation-induced cancer risk

    SciTech Connect

    Dunning, D.E. Jr.; Leggett, R.W.; Williams, L.R.

    1981-01-01

    The RICRAC computer code was developed at Oak Ridge National Laboratory to provide a versatile and convenient methodology for radiation risk assessment. The code allows as input essentially any dose pattern commonly encountered in risk assessments for either acute or chronic exposures, and it includes consideration of the age structure of the exposed population. Results produced by the analysis include the probability of one or more radiation-induced cancer deaths in a specified population, expected numbers of deaths, and expected years of life lost as a result of premature fatalities. These calculatons include consideration of competing risks of death from all other causes. The program also generates a probability frequency distribution of the expected number of cancers in any specified cohort resulting from a given radiation dose. The methods may be applied to any specified population and dose scenario.

  9. Radiation Leukemogenesis: Applying Basic Science of Epidemiological Estimates of Low Dose Risks and Dose-Rate Effects

    SciTech Connect

    Hoel, D. G.

    1998-11-01

    The next stage of work has been to examine more closely the A-bomb leukemia data which provides the underpinnings of the risk estimation of CML in the above mentioned manuscript. The paper by Hoel and Li (Health Physics 75:241-50) shows how the linear-quadratic model has basic non-linearities at the low dose region for the leukemias including CML. Pierce et. al., (Radiation Research 123:275-84) have developed distributions for the uncertainty in the estimated exposures of the A-bomb cohort. Kellerer, et. al., (Radiation and Environmental Biophysics 36:73-83) has further considered possible errors in the estimated neutron values and with changing RBE values with dose and has hypothesized that the tumor response due to gamma may not be linear. We have incorporated his neutron model and have constricted new A-bomb doses based on his model adjustments. The Hoel and Li dose response analysis has also been applied using the Kellerer neutron dose adjustments for the leukemias. Finally, both Pierce's dose uncertainties and Kellerer neutron adjustments are combined as well as the varying RBE with dose as suggested by Rossi and Zaider and used for leukemia dose-response analysis. First the results of Hoel and Li showing a significantly improved fit of the linear-quadratic dose response by the inclusion of a threshold (i.e. low-dose nonlinearity) persisted. This work has been complete for both solid tumor as well as leukemia for both mortality as well as incidence data. The results are given in the manuscript described below which has been submitted to Health Physics.

  10. State of the art coronary heart disease risk estimations based on the Framingham heart study.

    PubMed

    Reissigová, J; Tomecková, M

    2005-12-01

    The aim was to review the most interesting articles dealing with estimations of an individual's absolute coronary heart disease risk based on the Framingham heart study. Besides the Framingham coronary heart disease risk functions, results of validation studies of these Framingham risk functions are discussed. In general, the Framingham risk functions overestimated an individual's absolute risk in external (non-Framingham) populations with a lower occurrence of coronary heart disease compared with the Framingham population, and underestimated it in populations with a higher occurrence of coronary heart disease. Even if the calibration accuracy of the Framingham risk functions were not satisfying, the Framingham risk functions were able to rank individuals according to risk from low-risk to high-risk groups, with the discrimination ability of 60% and more. PMID:16419382

  11. Objective estimates improve risk stratification for primary graft dysfunction after lung transplantation

    PubMed Central

    Shah, Rupal J.; Diamond, Joshua M.; Cantu, Edward; Flesch, Judd; Lee, James C.; Lederer, David J.; Lama, Vibha N.; Orens, Jonathon; Weinacker, Ann; Wilkes, David S.; Roe, David; Bhorade, Sangeeta; Wille, Keith M.; Ware, Lorraine B.; Palmer, Scott M.; Crespo, Maria; Demissie, Ejigayehu; Sonnet, Joshua; Shah, Ashish; Kawut, Steven M.; Bellamy, Scarlett L.; Localio, A. Russell; Christie, Jason D.

    2016-01-01

    Primary graft dysfunction (PGD) is a major cause of early mortality after lung transplant. We aimed to define objective estimates of PGD risk based on readily available clinical variables, using a prospective study of 11 centers in Lung Transplant Outcomes Group (LTOG). Derivation included 1255 subjects from 2002–2010; with separate validation in 382 subjects accrued from 2011–2012. We used logistic regression to identify predictors of grade 3 PGD at 48/72 hours, and decision curve methods to assess impact on clinical decisions. 211/1255 subjects in the derivation and 56/382 subjects in the validation developed PGD. We developed 3 prediction models, where low-risk recipients had a normal BMI (18.5–25 kg/m2), COPD/CF, and absent or mild PH (mPAP< 40mmHg). All others were considered higher-risk. Low-risk recipients had a predicted PGD risk of 4–7%, and high-risk a predicted PGD risk of 15–18%. Adding a donor-smoking lung to a higher-risk recipient significantly increased PGD risk, although risk did not change in low-risk recipients. Validation demonstrated that probability estimates were generally accurate and that models worked best at baseline PGD incidences between 5–25%. We conclude that valid estimates of PGD risk can be produced using readily-available clinical variables. PMID:25877792

  12. A new Approach to Combine GRACE and ICESat Observations to Estimate Glacial Isostatic Adjustment in East Antarctic

    NASA Astrophysics Data System (ADS)

    Kallenberg, B.; Tregoning, P.; Purcell, A. P.

    2014-12-01

    Monitoring and understanding ongoing changes in Antarctic mass balance is of great interest, as the melting of the ice sheet would significantly contribute to global sea level changes. While scientists agree that the West Antarctic ice sheet is losing mass, opinions about the East Antarctic ice sheet are more widespread, with some areas showing an increase in mass. In recent years satellite missions have significantly contributed to the understanding of ongoing changes within the polar ice sheets, and became an important tool in detecting variations in ice height, ice mass and bedrock isostasy. The Gravity Recovery And Climate Experiment (GRACE) mission detects mass loss in regions where the ice sheet has its bed well below sea level and where warmer ocean water penetrates beneath the ice sheet, melting it from the base. Meanwhile an increase in mass has been observed in regions along the East Antarctic coastline, raising the question whether GRACE detects glacial isostatic adjustment due to ice mass loss or an actual increase in snowfall, contributing positively to surface mass balance. To improve our understanding on the contribution of glacial isostatic adjustment and surface mass balance to mass variations, we developed a new approach on how to subtract elevation changes observed by satellite altimetry from observed mass changes as detected by GRACE. We have established our own firn compaction model that we apply to the altimetry data to subtract changes due to the densification of snow, before using the ICESat observations. We will present results of the firn compaction model and our approach on combining GRACE and ICESat observations to separate the contribution of glacial isostatic adjustment from ongoing surface mass changes in East Antarctica.

  13. How reliable are the risk estimates for X-ray examinations in forensic age estimations? A safety update.

    PubMed

    Ramsthaler, F; Proschek, P; Betz, W; Verhoff, M A

    2009-05-01

    Possible biological side effects of exposure to X-rays are stochastic effects such as carcinogenesis and genetic alterations. In recent years, a number of new studies have been published about the special cancer risk that children may suffer from diagnostic X-rays. Children and adolescents who constitute many of the probands in forensic age-estimation proceedings are considerably more sensitive to the carcinogenic risks of ionizing radiation than adults. Established doses for X-ray examinations in forensic age estimations vary from less than 0.1 microSv (left hand X-ray) up to more than 800 microSv (computed tomography). Computed tomography in children, as a relatively high-dose procedure, is of particular interest because the doses involved are near to the lower limit of the doses observed and analyzed in A-bombing survivor studies. From these studies, direct epidemiological data exist concerning the lifetime cancer risk. Since there is no medical indication for forensic age examinations, it should be stressed that only safe methods are generally acceptable. This paper reviews current knowledge on cancer risks associated with diagnostic radiation and aims to help forensic experts, dentists, and pediatricians evaluate the risk from radiation when using X-rays in age-estimation procedures. PMID:19153756

  14. CubeSat mission design software tool for risk estimating relationships

    NASA Astrophysics Data System (ADS)

    Gamble, Katharine Brumbaugh; Lightsey, E. Glenn

    2014-09-01

    In an effort to make the CubeSat risk estimation and management process more scientific, a software tool has been created that enables mission designers to estimate mission risks. CubeSat mission designers are able to input mission characteristics, such as form factor, mass, development cycle, and launch information, in order to determine the mission risk root causes which historically present the highest risk for their mission. Historical data was collected from the CubeSat community and analyzed to provide a statistical background to characterize these Risk Estimating Relationships (RERs). This paper develops and validates the mathematical model based on the same cost estimating relationship methodology used by the Unmanned Spacecraft Cost Model (USCM) and the Small Satellite Cost Model (SSCM). The RER development uses general error regression models to determine the best fit relationship between root cause consequence and likelihood values and the input factors of interest. These root causes are combined into seven overall CubeSat mission risks which are then graphed on the industry-standard 5×5 Likelihood-Consequence (L-C) chart to help mission designers quickly identify areas of concern within their mission. This paper is the first to document not only the creation of a historical database of CubeSat mission risks, but, more importantly, the scientific representation of Risk Estimating Relationships.

  15. Setting health care capitations through diagnosis-based risk adjustment: a suitable model for the English NHS?

    PubMed

    Asthana, Sheena; Gibson, Alex

    2011-07-01

    The English system of health resource allocation has been described as the apotheosis of the area-level approach to setting health care capitations. However, recent policy developments have changed the scale at which commissioning decisions are made (and budgets allocated) with important implications for resource allocation. Doubts concerning the legitimacy of applying area-based formulae used to distribute resources between Primary Care Trusts (PCTs) to the much smaller scale required by Practice Based Commissioning (PBC) led the English Department of Health (DH) to introduce a new approach to setting health care budgets. To this end, practice-level allocations for acute services are now calculated using a diagnosis-based capitation model of the kind used in the United States and several other systems of competitive social health insurance. The new Coalition Government has proposed that these budgets are directly allocated to GP 'consortia', the new commissioning bodies in the NHS. This paper questions whether this is an appropriate development for a health system in which the major objective of resource allocation is to promote equal opportunity of access for equal needs. The chief reservation raised is that of circularity and the perpetuation of resource bias, the concern being that an existing social, demographic and geographical bias in the use of health care resources will be reinforced through the use of historic utilisation data. Demonstrating that there are legitimate reasons to suspect that this will be the case, the paper poses the question whether health systems internationally should more openly address the key limitations of empirical methods that select risk adjusters on the basis of existing patterns of health service utilisation. PMID:21093953

  16. Estimate of the wavelength dependency of ultraviolet carcinogenesis in humans and its relevance to the risk assessment of a stratospheric ozone depletion.

    PubMed

    de Gruijl, F R; Van der Leun, J C

    1994-10-01

    The wavelength dependency of carcinogenesis is an important factor in risk assessments pertaining to sources of ultraviolet radiation, the most important of which is the sun. This wavelength dependency cannot be measured directly in humans, but it has been measured in hairless mice, and represented in an action spectrum. An estimate of the action spectrum for humans can be produced by correcting for differences in epidermal transmission between mice and humans. This carcinogenic action spectrum for humans resembles the action spectrum for ultraviolet-induced erythema (sunburn), and results in small adjustments of earlier estimates of the effects of a stratospheric ozone depletion on skin cancer incidences. PMID:8083043

  17. Assessing uncertainty in published risk estimates using hexavalent chromium and lung cancer mortality as an example

    EPA Science Inventory

    Introduction: The National Research Council recommended quantitative evaluation of uncertainty in effect estimates for risk assessment. This analysis considers uncertainty across model forms and model parameterizations with hexavalent chromium [Cr(VI)] and lung cancer mortality a...

  18. Risk Assessment Tool for Estimating Your 10-Year Risk of Having a Heart Attack

    MedlinePlus

    ... Cardiovascular Risk: Systematic Evidence Review from the Risk Assessment Work Group The Evidence Report Full Report Accessible ... MB) Printer-friendly version (2 MB) Study Quality Assessment Tools Clinical Practice Guideline: Developed Under NHLBI Partnership ...

  19. Small-Sample Adjustments for Tests of Moderators and Model Fit Using Robust Variance Estimation in Meta-Regression

    ERIC Educational Resources Information Center

    Tipton, Elizabeth; Pustejovsky, James E.

    2015-01-01

    Meta-analyses often include studies that report multiple effect sizes based on a common pool of subjects or that report effect sizes from several samples that were treated with very similar research protocols. The inclusion of such studies introduces dependence among the effect size estimates. When the number of studies is large, robust variance…

  20. Smoking is a major preventable risk factor for Rheumatoid arthritis Estimations of risks after various exposures to cigarette smoke

    PubMed Central

    Källberg, Henrik; Ding, Bo; Padyukov, Leonid; Bengtsson, Camilla; Rönnelid, Johan; Klareskog, Lars; Alfredsson, Lars

    2011-01-01

    Background Earlier studies have demonstrated that smoking and genetic risk factors interact in providing an increased risk for Rheumatoid Arthritis (RA). Less is known on how smoking contributes to RA in the context of genetic variability, and what proportion of RA that may be caused by smoking. Objectives To determine the association between amount of smoking and risk of RA in the context of different HLA-DRB1 shared epitope (SE) alleles, and to estimate proportions of RA cases attributed to smoking. Design, Setting, and Participants Data from the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) case-control study encompassing 1204 cases and 871 controls were analysed. Main Outcome Measure Estimated odds ratio to develop RA and excess fraction of cases attributable to smoking according to amount of smoking and genotype. Results Smoking was estimated to be responsible for 35 % of the ACPA+ cases. For each HLA-DRB1 SE genotype, smoking was dose-dependently associated with increased risk of ACPA+ RA (p-trend<0.001). In individuals carrying two copies of the HLA-DRB1 shared epitope, 55 % of ACPA-positive RA were attributable to smoking. Conclusions Smoking is a preventable risk factor for RA. The increased risk due to smoking is dependent on amount of smoking and genotype. PMID:21149499

  1. Utilizing satellite precipitation estimates for streamflow forecasting via adjustment of mean field bias in precipitation data and assimilation of streamflow observations

    NASA Astrophysics Data System (ADS)

    Lee, Haksu; Zhang, Yu; Seo, Dong-Jun; Xie, Pingping

    2015-10-01

    This study explores mitigating bias in satellite quantitative precipitation estimates (SQPE) and improving hydrologic predictions at ungauged locations via adjustment of the mean field bias (MFB) in SQPE and data assimilation (DA) of streamflow observations in a distributed hydrologic model. In this study, a variational procedure is used to adjust MFB in Climate Prediction Center MORPHing (CMORPH) SQPE and assimilate streamflow observations at the outlet of Elk River Basin in Missouri into the distributed Sacramento Soil Moisture Accounting (SAC-SMA) and kinematic wave routing models. The benefits of assimilation are assessed by comparing the streamflow predictions with or without DA at both the outlet and an upstream location, and by comparing the soil moisture grids forced by CMORPH SQPE against those forced by higher-quality multisensor quantitative precipitation estimates (MQPE) from National Weather Service. Special attention is given to the dependence of the efficacy of DA on the quality and latency of the SQPE, and the impact of dynamic correction of MFB in the SQPE via DA. The results show that adjusting MFB in CMORPH SQPE in addition to assimilating outlet flow reduces 66% of the bias in the CMORPH SQPE analysis and the RMSE of 12-h streamflow predictions by 81% at the outlet and 34-62% at interior locations of the catchment. Compared to applying a temporally invariant MFB for the entire storm, the DA-based, dynamic MFB correction reduces the RMSE of 6-h streamflow prediction by 63% at the outlet and 39-69% at interior locations. It is also shown that the accuracy of streamflow prediction deteriorates if the delineation of the precipitation area by CMORPH SQPE is significantly different, as measured by the Hausdorff distance, from that by MQPE. When compared with adjusting MFB in the CMORPH SQPE over the entire assimilation window, adjusting the MFB for all but the latest 18 h (i.e., the latency of CMORPH SQPE) within the assimilation window reduces the

  2. Bayesian Framework for Water Quality Model Uncertainty Estimation and Risk Management

    EPA Science Inventory

    A formal Bayesian methodology is presented for integrated model calibration and risk-based water quality management using Bayesian Monte Carlo simulation and maximum likelihood estimation (BMCML). The primary focus is on lucid integration of model calibration with risk-based wat...

  3. Estimated occupational risk from bioaerosols generated during land application of Class B biosolids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been speculated that bioaerosols generated during land application of biosolids pose a serious occupational risk, but few scientific studies have been performed to assess levels of aerosolization of microorganisms from biosolids and to estimate the occupational risks of infection. This study ...

  4. Risk estimations, risk factors, and genetic variants associated with Alzheimer's disease in selected publications from the Framingham Heart Study.

    PubMed

    Weinstein, Galit; Wolf, Philip A; Beiser, Alexa S; Au, Rhoda; Seshadri, Sudha

    2013-01-01

    The study of Alzheimer's disease (AD) in the Framingham Heart Study (FHS), a multi-generational, community-based population study, began nearly four decades ago. In this overview, we highlight findings from seven prior publications that examined lifetime risk estimates for AD, environmental risk factors for AD, circulating and imaging markers of aging-related brain injury, and explorations on the genetics underlying AD. First, we describe estimations of the lifetime risk of AD. These estimates are distinguished from other measures of disease burden and have substantial public health implications. We then describe prospective studies of environmental AD risk factors: one examined the association between plasma levels of omega-3 fatty-acid and risk of incident AD, the other explored the association of diabetes to this risk in subsamples with specific characteristics. With evidence of inflammation as an underlying mechanism, we also describe findings from a study that compared the effects of serum cytokines and spontaneous production of peripheral blood mononuclear cell cytokines on AD risk. Investigating AD related endophenotypes increases sensitivity in identifying risk factors and can be used to explore pathophysiologic pathways between a risk factor and the disease. We describe findings of an association between large volume of white matter hyperintensities and a specific pattern of cognitive deficits in non-demented participants. Finally, we summarize our findings from two genetic studies: The first used genome-wide association (GWA) and family-based association methods to explore the genetic basis of cognitive and structural brain traits. The second is a large meta-analysis GWA study of AD, in which novel loci of AD susceptibility were found. Together, these findings demonstrate the FHS multi-directional efforts in investigating dementia and AD. PMID:22796871

  5. Uncertainties in Estimates of the Risks of Late Effects from Space Radiation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Schimmerling, W.; Wilson, J. W.; Peterson, L. E.; Saganti, P.; Dicelli, J. F.

    2002-01-01

    The health risks faced by astronauts from space radiation include cancer, cataracts, hereditary effects, and non-cancer morbidity and mortality risks related to the diseases of the old age. Methods used to project risks in low-Earth orbit are of questionable merit for exploration missions because of the limited radiobiology data and knowledge of galactic cosmic ray (GCR) heavy ions, which causes estimates of the risk of late effects to be highly uncertain. Risk projections involve a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Within the linear-additivity model, we use Monte-Carlo sampling from subjective uncertainty distributions in each factor to obtain a Maximum Likelihood estimate of the overall uncertainty in risk projections. The resulting methodology is applied to several human space exploration mission scenarios including ISS, lunar station, deep space outpost, and Mar's missions of duration of 360, 660, and 1000 days. The major results are the quantification of the uncertainties in current risk estimates, the identification of factors that dominate risk projection uncertainties, and the development of a method to quantify candidate approaches to reduce uncertainties or mitigate risks. The large uncertainties in GCR risk projections lead to probability distributions of risk that mask any potential risk reduction using the "optimization" of shielding materials or configurations. In contrast, the design of shielding optimization approaches for solar particle events and trapped protons can be made at this time, and promising technologies can be shown to have merit using our approach. The methods used also make it possible to express risk management objectives in terms of quantitative objective's, i.e., the number of days in space without exceeding a given risk level within well defined confidence limits.

  6. Estimating risks to aquatic life using quantile regression

    USGS Publications Warehouse

    Schmidt, Travis S.; Clements, William H.; Cade, Brian S.

    2012-01-01

    One of the primary goals of biological assessment is to assess whether contaminants or other stressors limit the ecological potential of running waters. It is important to interpret responses to contaminants relative to other environmental factors, but necessity or convenience limit quantification of all factors that influence ecological potential. In these situations, the concept of limiting factors is useful for data interpretation. We used quantile regression to measure risks to aquatic life exposed to metals by including all regression quantiles (τ  =  0.05–0.95, by increments of 0.05), not just the upper limit of density (e.g., 90th quantile). We measured population densities (individuals/0.1 m2) of 2 mayflies (Rhithrogena spp., Drunella spp.) and a caddisfly (Arctopsyche grandis), aqueous metal mixtures (Cd, Cu, Zn), and other limiting factors (basin area, site elevation, discharge, temperature) at 125 streams in Colorado. We used a model selection procedure to test which factor was most limiting to density. Arctopsyche grandis was limited by other factors, whereas metals limited most quantiles of density for the 2 mayflies. Metals reduced mayfly densities most at sites where other factors were not limiting. Where other factors were limiting, low mayfly densities were observed despite metal concentrations. Metals affected mayfly densities most at quantiles above the mean and not just at the upper limit of density. Risk models developed from quantile regression showed that mayfly densities observed at background metal concentrations are improbable when metal mixtures are at US Environmental Protection Agency criterion continuous concentrations. We conclude that metals limit potential density, not realized average density. The most obvious effects on mayfly populations were at upper quantiles and not mean density. Therefore, we suggest that policy developed from mean-based measures of effects may not be as useful as policy based on the concept of

  7. Overview of Risk-Estimation Tools for Primary Prevention of Cardiovascular Diseases in European Populations.

    PubMed

    Gorenoi, Vitali; Hagen, Anja

    2015-06-01

    To identify persons with a high risk for cardiovascular diseases (CVD) special tools (scores, charts, graphics or computer programs) for CVD-risk assessment based on levels of the certain risk factors have been constructed. The applicability of these instruments depends on the derivation cohorts, considered risk factors and endpoints, applied statistical methods as well as used formats. The review addresses the risk-estimation tools for primary prevention of CVD potentially relevant for European populations. The risk-estimation tools were identified using two previously published systematic reviews as well as conducting a literature search in MEDLINE and a manual search. Only instruments were considered which were derived from cohorts of at least 1,000 participants of one gender without pre-existing CVD, enable risk assessment for a period of at least 5 years, were designed for an age-range of at least 25 years and published after the year 2000. A number of risk-estimation tools for CVD derived from single European, several European and from non-European cohorts were identified. From a clinical perspective, seem to be preferable instruments for risk of CVD contemporary developed for the population of interest, which use easily accessible measures and show a high discriminating ability. Instruments, restricting risk-estimation to certain cardiovascular events, recalibrated high-accuracy tools or tools derived from European populations with similar risk factors distribution and CVD-incidence are the second choice. In younger people, calculating the relative risk or cardiovascular age equivalence measures may be of more benefit. PMID:26851417

  8. Estimating Toxicity Pathway Activating Doses for High Throughput Chemical Risk Assessments

    EPA Science Inventory

    Estimating a Toxicity Pathway Activating Dose (TPAD) from in vitro assays as an analog to a reference dose (RfD) derived from in vivo toxicity tests would facilitate high throughput risk assessments of thousands of data-poor environmental chemicals. Estimating a TPAD requires def...

  9. ASSESSMENT OF METHODS FOR ESTIMATING RISK TO BIRDS FROM INGESTION OF CONTAMINATED GRIT PARTICLES (FINAL REPORT)

    EPA Science Inventory

    The 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 mo...

  10. Toxoplasma gondii Infection in Kyrgyzstan: Seroprevalence, Risk Factor Analysis, and Estimate of Congenital and AIDS-Related Toxoplasmosis

    PubMed Central

    Bodosheva, Aigerim; Kuttubaev, Omurbek; Hehl, Adrian B.; Tanner, Isabelle; Ziadinov, Iskender; Torgerson, Paul R.; Deplazes, Peter

    2013-01-01

    Background HIV-prevalence, as well as incidence of zoonotic parasitic diseases like cystic echinococcosis, has increased in the Kyrgyz Republic due to fundamental socio-economic changes after the breakdown of the Soviet Union. The possible impact on morbidity and mortality caused by Toxoplasma gondii infection in congenital toxoplasmosis or as an opportunistic infection in the emerging AIDS pandemic has not been reported from Kyrgyzstan. Methodology/Principal Findings We screened 1,061 rural and 899 urban people to determine the seroprevalence of T. gondii infection in 2 representative but epidemiologically distinct populations in Kyrgyzstan. The rural population was from a typical agricultural district where sheep husbandry is a major occupation. The urban population was selected in collaboration with several diagnostic laboratories in Bishkek, the largest city in Kyrgyzstan. We designed a questionnaire that was used on all rural subjects so a risk-factor analysis could be undertaken. The samples from the urban population were anonymous and only data with regard to age and gender was available. Estimates of putative cases of congenital and AIDS-related toxoplasmosis in the whole country were made from the results of the serology. Specific antibodies (IgG) against Triton X-100 extracted antigens of T. gondii tachyzoites from in vitro cultures were determined by ELISA. Overall seroprevalence of infection with T. gondii in people living in rural vs. urban areas was 6.2% (95%CI: 4.8–7.8) (adjusted seroprevalence based on census figures 5.1%, 95% CI 3.9–6.5), and 19.0% (95%CI: 16.5–21.7) (adjusted 16.4%, 95% CI 14.1–19.3), respectively, without significant gender-specific differences. The seroprevalence increased with age. Independently low social status increased the risk of Toxoplasma seropositivity while increasing numbers of sheep owned decreased the risk of seropositivity. Water supply, consumption of unpasteurized milk products or undercooked meat, as

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

    SciTech Connect

    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.

  12. Parental dysphoria and children's adjustment: marital conflict styles, children's emotional security, and parenting as mediators of risk.

    PubMed

    Du Rocher Schudlich, Tina D; Cummings, E Mark

    2007-08-01

    Dimensions of martial conflict, children's emotional security regarding interparental conflict, and parenting style were examined as mediators between parental dysphoria and child adjustment. A community sample of 262 children, ages 8-16, participated with their parents. Behavioral observations were made of parents' interactions during marital conflict resolution tasks, which children later observed to assess their emotional security. Questionnaires assessed parents' dysphoria, parenting, and children's adjustment. Structural equation modeling indicated that parental dysphoria was linked with child adjustment through specific and distinct mediating family processes, including marital conflict and parenting. Children's emotional security in the context of particular marital conflict styles also mediated relations between parental dysphoria and child adjustment problems, with similar pathways found for mothers and fathers. These pathways remained significant even after significant parenting contributions were considered. PMID:17390219

  13. Space Radiation Heart Disease Risk Estimates for Lunar and Mars Missions

    NASA Technical Reports Server (NTRS)

    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.

  14. Biased Exposure–Health Effect Estimates from Selection in Cohort Studies: Are Environmental Studies at Particular Risk?

    PubMed Central

    Sparrow, David; Hu, Howard; Power, Melinda C.

    2015-01-01

    Background The process of creating a cohort or cohort substudy may induce misleading exposure–health effect associations through collider stratification bias (i.e., selection bias) or bias due to conditioning on an intermediate. Studies of environmental risk factors may be at particular risk. Objectives We aimed to demonstrate how such biases of the exposure–health effect association arise and how one may mitigate them. Methods We used directed acyclic graphs and the example of bone lead and mortality (all-cause, cardiovascular, and ischemic heart disease) among 835 white men in the Normative Aging Study (NAS) to illustrate potential bias related to recruitment into the NAS and the bone lead substudy. We then applied methods (adjustment, restriction, and inverse probability of attrition weighting) to mitigate these biases in analyses using Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Results Analyses adjusted for age at bone lead measurement, smoking, and education among all men found HRs (95% CI) for the highest versus lowest tertile of patella lead of 1.34 (0.90, 2.00), 1.46 (0.86, 2.48), and 2.01 (0.86, 4.68) for all-cause, cardiovascular, and ischemic heart disease mortality, respectively. After applying methods to mitigate the biases, the HR (95% CI) among the 637 men analyzed were 1.86 (1.12, 3.09), 2.47 (1.23, 4.96), and 5.20 (1.61, 16.8), respectively. Conclusions Careful attention to the underlying structure of the observed data is critical to identifying potential biases and methods to mitigate them. Understanding factors that influence initial study participation and study loss to follow-up is critical. Recruitment of population-based samples and enrolling participants at a younger age, before the potential onset of exposure-related health effects, can help reduce these potential pitfalls. Citation Weisskopf MG, Sparrow D, Hu H, Power MC. 2015. Biased exposure–health effect estimates

  15. [Estimation of the radiation risk of determined effects of human exposure in space].

    PubMed

    Petrov, V M; Vasina, Iu I; Vlasov, A G; Shurshakov, V A

    2001-01-01

    Subject of the paper is possibility to estimate radiation risk of determined consequences of exposure to solar space rays as a probability of violation of established dose limits. Analysis of specifies of spacecrew exposure to solar space rays in a long-term, particularly interplanetary mission suggests that immediate introduction of the principle in the radiation health policy can result in serious errors, mainly exaggeration, in determination of radiation risk. Proposed are approaches to radiation risk estimation with consideration of the specific of human exposure in space. PMID:11915752

  16. A simple procedure for estimating pseudo risk ratios from exposure to non-carcinogenic chemical mixtures.

    PubMed

    Scinicariello, Franco; Portier, Christopher

    2016-03-01

    Non-cancer risk assessment traditionally assumes a threshold of effect, below which there is a negligible risk of an adverse effect. The Agency for Toxic Substances and Disease Registry derives health-based guidance values known as Minimal Risk Levels (MRLs) as estimates of the toxicity threshold for non-carcinogens. Although the definition of an MRL, as well as EPA reference dose values (RfD and RfC), is a level that corresponds to "negligible risk," they represent daily exposure doses or concentrations, not risks. We present a new approach to calculate the risk at exposure to specific doses for chemical mixtures, the assumption in this approach is to assign de minimis risk at the MRL. The assigned risk enables the estimation of parameters in an exponential model, providing a complete dose-response curve for each compound from the chosen point of departure to zero. We estimated parameters for 27 chemicals. The value of k, which determines the shape of the dose-response curve, was moderately insensitive to the choice of the risk at the MRL. The approach presented here allows for the calculation of a risk from a single substance or the combined risk from multiple chemical exposures in a community. The methodology is applicable from point of departure data derived from quantal data, such as data from benchmark dose analyses or from data that can be transformed into probabilities, such as lowest-observed-adverse-effect level. The individual risks are used to calculate risk ratios that can facilitate comparison and cost-benefit analyses of environmental contamination control strategies. PMID:25667015

  17. Uncertainties in estimates of the risks of late effects from space radiation

    NASA Technical Reports Server (NTRS)

    Cucinotta, F. A.; Schimmerling, W.; Wilson, J. W.; Peterson, L. E.; Saganti, P. B.; Dicello, J. F.

    2004-01-01

    Methods used to project risks in low-Earth orbit are of questionable merit for exploration missions because of the limited radiobiology data and knowledge of galactic cosmic ray (GCR) heavy ions, which causes estimates of the risk of late effects to be highly uncertain. Risk projections involve a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Using the linear-additivity model for radiation risks, we use Monte-Carlo sampling from subjective uncertainty distributions in each factor to obtain an estimate of the overall uncertainty in risk projections. The resulting methodology is applied to several human space exploration mission scenarios including a deep space outpost and Mars missions of duration of 360, 660, and 1000 days. The major results are the quantification of the uncertainties in current risk estimates, the identification of factors that dominate risk projection uncertainties, and the development of a method to quantify candidate approaches to reduce uncertainties or mitigate risks. The large uncertainties in GCR risk projections lead to probability distributions of risk that mask any potential risk reduction using the "optimization" of shielding materials or configurations. In contrast, the design of shielding optimization approaches for solar particle events and trapped protons can be made at this time and promising technologies can be shown to have merit using our approach. The methods used also make it possible to express risk management objectives in terms of quantitative metrics, e.g., the number of days in space without exceeding a given risk level within well-defined confidence limits. Published by Elsevier Ltd on behalf of COSPAR.

  18. Uncertainties in estimates of the risks of late effects from space radiation.

    PubMed

    Cucinotta, F A; Schimmerling, W; Wilson, J W; Peterson, L E; Saganti, P B; Dicello, J F

    2004-01-01

    Methods used to project risks in low-Earth orbit are of questionable merit for exploration missions because of the limited radiobiology data and knowledge of galactic cosmic ray (GCR) heavy ions, which causes estimates of the risk of late effects to be highly uncertain. Risk projections involve a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Using the linear-additivity model for radiation risks, we use Monte-Carlo sampling from subjective uncertainty distributions in each factor to obtain an estimate of the overall uncertainty in risk projections. The resulting methodology is applied to several human space exploration mission scenarios including a deep space outpost and Mars missions of duration of 360, 660, and 1000 days. The major results are the quantification of the uncertainties in current risk estimates, the identification of factors that dominate risk projection uncertainties, and the development of a method to quantify candidate approaches to reduce uncertainties or mitigate risks. The large uncertainties in GCR risk projections lead to probability distributions of risk that mask any potential risk reduction using the "optimization" of shielding materials or configurations. In contrast, the design of shielding optimization approaches for solar particle events and trapped protons can be made at this time and promising technologies can be shown to have merit using our approach. The methods used also make it possible to express risk management objectives in terms of quantitative metrics, e.g., the number of days in space without exceeding a given risk level within well-defined confidence limits. PMID:15881779

  19. Biologically based risk estimation for radiation-induced CML. Inferences from BCR and ABL geometric distributions.

    PubMed

    Radivoyevitch, T; Kozubek, S; Sachs, R K

    2001-03-01

    Chronic myeloid leukemia (CML) invites biologically based radiation risk modeling because CML is simultaneously well-understood, homogeneous and prevalent. CML is known to be caused by a translocation involving the ABL and BCR genes, almost all CML patients have the BCR-ABL translocation, and CML is prevalent enough that its induction is unequivocally detected among Hiroshima A-bomb survivors. In a previous paper, a linear-quadratic-exponential (LQE) dose-response model was used to estimate the lifetime excess risk of CML in the limit of low doses of gamma-rays, R gamma. This estimate assumed that BCR-ABL translocation dose-response curves in stem cells for both neutrons and gamma-rays, differ only by a common proportionality constant from dicentric aberration dose-response curves in lymphocytes. In the present paper we challenge this assumption by predicting the BCR-ABL dose response. The predictions are based on the biophysical theory of dual radiation action (TDRA) as it applies to recent BCR-to-ABL distance data in G0 human lymphocytes; this data shows BCR and ABL geometric distributions that are not uniform and not independent, with close association of the two genes in some cells. The analysis speaks against the previous proportionality assumption. We compute 11 plausible LQE estimates of R gamma, 2 based on the proportionality assumption and 9 based on TDRA predictions. For each estimate of R gamma we also compute an associated estimate of the number of CML target cells, N; the biological basis of the LQE model allows us to form such estimates. Consistency between N and hematological considerations provides a plausibility check of the risk estimates. Within the group of estimates investigated, the most plausible lifetime excess risk estimates tend to lie near R gamma = 0.01 Gy-1, substantially higher than risk estimates based on the proportionality assumption. PMID:11357705

  20. Enhancing Global Land Surface Hydrology Estimates from the NASA MERRA Reanalysis Using Precipitation Observations and Model Parameter Adjustments

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf; Koster, Randal; DeLannoy, Gabrielle; Forman, Barton; Liu, Qing; Mahanama, Sarith; Toure, Ally

    2011-01-01

    The Modern-Era Retrospective analysis for Research and Applications (MERRA) is a state-of-the-art reanalysis that provides. in addition to atmospheric fields. global estimates of soil moisture, latent heat flux. snow. and runoff for J 979-present. This study introduces a supplemental and improved set of land surface hydrological fields ('MERRA-Land') generated by replaying a revised version of the land component of the MERRA system. Specifically. the MERRA-Land estimates benefit from corrections to the precipitation forcing with the Global Precipitation Climatology Project pentad product (version 2.1) and from revised parameters in the rainfall interception model, changes that effectively correct for known limitations in the MERRA land surface meteorological forcings. The skill (defined as the correlation coefficient of the anomaly time series) in land surface hydrological fields from MERRA and MERRA-Land is assessed here against observations and compared to the skill of the state-of-the-art ERA-Interim reanalysis. MERRA-Land and ERA-Interim root zone soil moisture skills (against in situ observations at 85 US stations) are comparable and significantly greater than that of MERRA. Throughout the northern hemisphere, MERRA and MERRA-Land agree reasonably well with in situ snow depth measurements (from 583 stations) and with snow water equivalent from an independent analysis. Runoff skill (against naturalized stream flow observations from 15 basins in the western US) of MERRA and MERRA-Land is typically higher than that of ERA-Interim. With a few exceptions. the MERRA-Land data appear more accurate than the original MERRA estimates and are thus recommended for those interested in using '\\-tERRA output for land surface hydrological studies.

  1. Response bias, weighting adjustments, and design effects in the Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS)

    PubMed Central

    Kessler, Ronald C.; Heeringa, Steven G.; Colpe, Lisa J.; Fullerton, Carol S.; Gebler, Nancy; Hwang, Irving; Naifeh, James A.; Nock, Matthew K.; Sampson, Nancy A.; Schoenbaum, Michael; Zaslavsky, Alan M.; Stein, Murray B.; Ursano, Robert J.

    2014-01-01

    The Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS) is a multi-component epidemiological and neurobiological study designed to generate actionable recommendations to reduce U.S. Army suicides and increase knowledge about determinants of suicidality. Three Army STARRS component studies are large-scale surveys: one of new soldiers prior to beginning Basic Combat Training (BCT; n=50,765 completed self-administered questionnaires); another of other soldiers exclusive of those in BCT (n=35,372); and a third of three Brigade Combat Teams about to deploy to Afghanistan who are being followed multiple times after returning from deployment (n= 9,421). Although the response rates in these surveys are quite good (72.0-90.8%), questions can be raised about sample biases in estimating prevalence of mental disorders and suicidality, the main outcomes of the surveys based on evidence that people in the general population with mental disorders are under-represented in community surveys. This paper presents the results of analyses designed to determine whether such bias exists in the Army STARRS surveys and, if so, to develop weights to correct for these biases. Data are also presented on sample inefficiencies introduced by weighting and sample clustering and on analyses of the trade-off between bias and efficiency in weight trimming. PMID:24318218

  2. Comparison of Paper-and-Pencil versus Web Administration of the Youth Risk Behavior Survey (YRBS): Risk Behavior Prevalence Estimates

    ERIC Educational Resources Information Center

    Eaton, Danice K.; Brener, Nancy D.; Kann, Laura; Denniston, Maxine M.; McManus, Tim; Kyle, Tonja M.; Roberts, Alice M.; Flint, Katherine H.; Ross, James G.

    2010-01-01

    The authors examined whether paper-and-pencil and Web surveys administered in the school setting yield equivalent risk behavior prevalence estimates. Data were from a methods study conducted by the Centers for Disease Control and Prevention (CDC) in spring 2008. Intact classes of 9th- or 10th-grade students were assigned randomly to complete a…

  3. Adjusting for small-sample non-normality of design event estimators under a generalized Pareto distribution

    NASA Astrophysics Data System (ADS)

    Ashkar, Fahim; El Adlouni, Salah-Eddine

    2015-11-01

    The generalized Pareto distribution (GPD) is a widely used frequency model for fitting extremes in hydrology, especially to fit exceedances over a threshold in the peaks-over-threshold (POT) modeling of floods or other extreme hydrological phenomena. A key goal in fitting frequency distributions to data is to allow the estimation of distribution quantiles, which in hydrology are often used as "design events". The maximum likelihood (ML) method is a recommended method for fitting the GPD to data. To provide a measure of the statistical error involved in the estimation of design events, confidence intervals for quantiles (CIQs) have to be calculated. Hydrologists have traditionally used large-sample theory to construct such CIQs, but it is shown in the present study that this leads to inaccurate results for quantiles in the right-tail of a GPD. An improvement is therefore proposed for these classically obtained CIQs under a GPD model fitted by ML. The conventional and proposed approaches are compared through Monte Carlo (MC) simulation, and the resulting recommendations are put to use in a hydrological application.

  4. ESTIMATING RISK TO CALIFORNIA ENERGY INFRASTRUCTURE FROM PROJECTED CLIMATE CHANGE

    SciTech Connect

    Sathaye, Jayant; Dale, Larry; Larsen, Peter; Fitts, Gary; Koy, Kevin; Lewis, Sarah; Lucena, Andre

    2011-06-22

    This report outlines the results of a study of the impact of climate change on the energy infrastructure of California and the San Francisco Bay region, including impacts on power plant generation; transmission line and substation capacity during heat spells; wildfires near transmission lines; sea level encroachment upon power plants, substations, and natural gas facilities; and peak electrical demand. Some end-of-century impacts were projected:Expected warming will decrease gas-fired generator efficiency. The maximum statewide coincident loss is projected at 10.3 gigawatts (with current power plant infrastructure and population), an increase of 6.2 percent over current temperature-induced losses. By the end of the century, electricity demand for almost all summer days is expected to exceed the current ninetieth percentile per-capita peak load. As much as 21 percent growth is expected in ninetieth percentile peak demand (per-capita, exclusive of population growth). When generator losses are included in the demand, the ninetieth percentile peaks may increase up to 25 percent. As the climate warms, California's peak supply capacity will need to grow faster than the population.Substation capacity is projected to decrease an average of 2.7 percent. A 5C (9F) air temperature increase (the average increase predicted for hot days in August) will diminish the capacity of a fully-loaded transmission line by an average of 7.5 percent.The potential exposure of transmission lines to wildfire is expected to increase with time. We have identified some lines whose probability of exposure to fire are expected to increase by as much as 40 percent. Up to 25 coastal power plants and 86 substations are at risk of flooding (or partial flooding) due to sea level rise.

  5. Laypersons’ Responses to the Communication of Uncertainty Regarding Cancer Risk Estimates

    PubMed Central

    Han, Paul K. J.; Klein, William M. P.; Lehman, Thomas C.; Massett, Holly; Lee, Simon C.; Freedman, Andrew N.

    2009-01-01

    Objective To explore laypersons’ responses to the communication of uncertainty associated with individualized cancer risk estimates and to identify reasons for individual differences in these responses. Design A qualitative study was conducted using focus groups. Participants were informed about a new colorectal cancer risk prediction model, and presented with hypothetical individualized risk estimates using presentation formats varying in expressed uncertainty (range v. point estimate). Semistructured interviews explored participants’ responses to this information. Participants and Setting Eight focus groups were conducted with 48 adults aged 50 to 74 residing in 2 major US metropolitan areas, Chicago, IL and Washington, DC. Purposive sampling was used to recruit participants with a high school or greater education, some familiarity with information technology, and no personal or immediate family history of cancer. Results Participants identified several sources of uncertainty regarding cancer risk estimates, including missing data, limitations in accuracy and source credibility, and conflicting information. In comparing presentation formats, most participants reported greater worry and perceived risk with the range than with the point estimate, consistent with the phenomenon of “ambiguity aversion.” However, others reported the opposite effect or else indifference between formats. Reasons suggested by participants’ responses included individual differences in optimism and motivations to reduce feelings of vulnerability and personal lack of control. Perceptions of source credibility and risk mutability emerged as potential mediating factors. Conclusions Laypersons’ responses to the communication of uncertainty regarding cancer risk estimates differ, and include both heightened and diminished risk perceptions. These differences may be attributable to personality, cognitive, and motivational factors. PMID:19470720

  6. Assessment of the value of a genetic risk score in improving the estimation of coronary risk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The American Heart Association has established criteria for the evaluation of novel markers of cardiovascular risk. In accordance with these criteria, we assessed the association between a multi-locus genetic risk score (GRS) and incident coronary heart disease (CHD), and evaluated whether this GRS ...

  7. Mobile Applications for Type 2 Diabetes Risk Estimation: a Systematic Review.

    PubMed

    Fijacko, Nino; Brzan, Petra Povalej; Stiglic, Gregor

    2015-10-01

    Screening for chronical diseases like type 2 diabetes can be done using different methods and various risk tests. This study present a review of type 2 diabetes risk estimation mobile applications focusing on their functionality and availability of information on the underlying risk calculators. Only 9 out of 31 reviewed mobile applications, featured in three major mobile application stores, disclosed the name of risk calculator used for assessing the risk of type 2 diabetes. Even more concerning, none of the reviewed applications mentioned that they are collecting the data from users to improve the performance of their risk estimation calculators or offer users the descriptive statistics of the results from users that already used the application. For that purpose the questionnaires used for calculation of risk should be upgraded by including the information on the most recent blood sugar level measurements from users. Although mobile applications represent a great future potential for health applications, developers still do not put enough emphasis on informing the user of the underlying methods used to estimate the risk for a specific clinical condition. PMID:26303152

  8. Estimating risk at a Superfund site using passive sampling devices as biological surrogates in human health risk models

    PubMed Central

    Allan, Sarah E.; Sower, Gregory J.; Anderson, Kim A.

    2013-01-01

    Passive sampling devices (PSDs) sequester the freely dissolved fraction of lipophilic contaminants, mimicking passive chemical uptake and accumulation by biomembranes and lipid tissues. Public Health Assessments that inform the public about health risks from exposure to contaminants through consumption of resident fish are generally based on tissue data, which can be difficulties to obtain and requires destructive sampling. The purpose of this study is to apply PSD data in a Public Health Assessment to demonstrate that PSDs can be used as a biological surrogate to evaluate potential human health risks and elucidate spatio-temporal variations in risk. PSDs were used to measure polycyclic aromatic hydrocarbons (PAHs) in the Willamette River; upriver, downriver and within the Portland Harbor Superfund megasite for three years during wet and dry seasons. Based on an existing Public Health Assessment for this area, concentrations of PAHs in PSDs were substituted for fish tissue concentrations. PSD measured PAH concentrations captured the magnitude, range and variability of PAH concentrations reported for fish/shellfish from Portland Harbor. Using PSD results in place of fish data revealed an unacceptable risk level for cancer in all seasons but no unacceptable risk for non-cancer endpoints. Estimated cancer risk varied by several orders of magnitude based on season and location. Sites near coal tar contamination demonstrated the highest risk, particularly during the dry season and remediation activities. Incorporating PSD data into Public Health Assessments provides specific spatial and temporal contaminant exposure information that can assist public health professionals in evaluating human health risks. PMID:21741671

  9. Estimating quality adjusted progression free survival of first-line treatments for EGFR mutation positive non small cell lung cancer patients in The Netherlands

    PubMed Central

    2012-01-01

    Background Gefitinib, a tyrosine kinase inhibitor, is an effective treatment in advanced non-small cell lung cancer (NSCLC) patients with an activating mutation in the epidermal growth factor receptor (EGFR). Randomised clinical trials showed a benefit in progression free survival for gefitinib versus doublet chemotherapy regimens in patients with an activated EGFR mutation (EGFR M+). From a patient perspective, progression free survival is important, but so is health-related quality of life. Therefore, this analysis evaluates the Quality Adjusted progression free survival of gefitinib versus three relevant doublet chemotherapies (gemcitabine/cisplatin (Gem/Cis); pemetrexed/cisplatin (Pem/Cis); paclitaxel/carboplatin (Pac/Carb)) in a Dutch health care setting in patients with EGFR M+ stage IIIB/IV NSCLC. This study uses progression free survival rather than overall survival for its time frame in order to better compare the treatments and to account for the influence that subsequent treatment lines would have on overall survival analysis. Methods Mean progression free survival for Pac/Carb was obtained by extrapolating the median progression free survival as reported in the Iressa-Pan-Asia Study (IPASS). Data from a network meta-analysis was used to estimate the mean progression free survival for therapies of interest relative to Pac/Carb. Adjustment for health-related quality of life was done by incorporating utilities for the Dutch population, obtained by converting FACT-L data (from IPASS) to utility values and multiplying these with the mean progression free survival for each treatment arm to determine the Quality Adjusted progression free survival. Probabilistic sensitivity analysis was carried out to determine 95% credibility intervals. Results The Quality Adjusted progression free survival (PFS) (mean, (95% credibility interval)) was 5.2 months (4.5; 5.8) for Gem/Cis, 5.3 months (4.6; 6.1) for Pem/Cis; 4.9 months (4.4; 5.5) for Pac/Carb and 8.3 (7.0; 9.9) for

  10. Model-Based Estimates of the Effects of Efavirenz on Bedaquiline Pharmacokinetics and Suggested Dose Adjustments for Patients Coinfected with HIV and Tuberculosis

    PubMed Central

    Svensson, Elin M.; Aweeka, Francesca; Park, Jeong-Gun; Marzan, Florence; Karlsson, Mats O.

    2013-01-01

    Safe, effective concomitant treatment regimens for tuberculosis (TB) and HIV infection are urgently needed. Bedaquiline (BDQ) is a promising new anti-TB drug, and efavirenz (EFV) is a commonly used antiretroviral. Due to EFV's induction of cytochrome P450 3A4, the metabolic enzyme responsible for BDQ biotransformation, the drugs are expected to interact. Based on data from a phase I, single-dose pharmacokinetic study, a nonlinear mixed-effects model characterizing BDQ pharmacokinetics and interaction with multiple-dose EFV was developed. BDQ pharmacokinetics were best described by a 3-compartment disposition model with absorption through a dynamic transit compartment model. Metabolites M2 and M3 were described by 2-compartment models with clearance of BDQ and M2, respectively, as input. Impact of induction was described as an instantaneous change in clearance 1 week after initialization of EFV treatment and estimated for all compounds. The model predicts average steady-state concentrations of BDQ and M2 to be reduced by 52% (relative standard error [RSE], 3.7%) with chronic coadministration. A range of models with alternative structural assumptions regarding onset of induction effect and fraction metabolized resulted in similar estimates of the typical reduction and did not offer a markedly better fit to data. Simulations to investigate alternative regimens mitigating the estimated interaction effect were performed. The results suggest that simple adjustments of the standard regimen during EFV coadministration can prevent reduced exposure to BDQ without increasing exposures to M2. However, exposure to M3 would increase. Evaluation in clinical trials of adjusted regimens is necessary to ensure appropriate dosing for HIV-infected TB patients on an EFV-based regimen. PMID:23571542

  11. Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk

    PubMed Central

    Nasr, P; Yip, G; Scaife, J E; House, T; Thomas, S J; Harris, F; Owen, P J; Hull, P

    2014-01-01

    Objective: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. Methods: 34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis. Results: 28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II–IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000. Conclusion: These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. Advances in knowledge: The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis. PMID:25089852

  12. The Predictive Relationship between Temperament, School Adjustment, and Academic Achievement: A 2-Year Longitudinal Study of Children At-Risk

    ERIC Educational Resources Information Center

    Al-Hendawi, Maha

    2010-01-01

    Individual differences in temperament can be a risk or a protective factor for a child, especially for children at-risk who possess single or multiple risk factors that may interfere with their educational success and affect their healthy development and their life-long outcomes. This research study examined the concurrent and longitudinal…

  13. Parenchymal Texture Analysis in Digital Breast Tomosynthesis for Breast Cancer Risk Estimation: A Preliminary Study

    PubMed Central

    Kontos, Despina; Bakic, Predrag R.; Carton, Ann-Katherine; Troxel, Andrea B.; Conant, Emily F.; Maidment, Andrew D.A.

    2009-01-01

    Rationale and Objectives Studies have demonstrated a relationship between mammographic parenchymal texture and breast cancer risk. Although promising, texture analysis in mammograms is limited by tissue superimposition. Digital breast tomosynthesis (DBT) is a novel tomographic x-ray breast imaging modality that alleviates the effect of tissue superimposition, offering superior parenchymal texture visualization compared to mammography. Our study investigates the potential advantages of DBT parenchymal texture analysis for breast cancer risk estimation. Materials and Methods DBT and digital mammography (DM) images of 39 women were analyzed. Texture features, shown in studies with mammograms to correlate with cancer risk, were computed from the retroareolar breast region. We compared the relative performance of DBT and DM texture features in correlating with two measures of breast cancer risk: (i) the Gail and Claus risk estimates, and (ii) mammographic breast density. Linear regression was performed to model the association between texture features and increasing levels of risk. Results No significant correlation was detected between parenchymal texture and the Gail and Claus risk estimates. Significant correlations were observed between texture features and breast density. Overall, the DBT texture features demonstrated stronger correlations with breast percent density (PD) than DM (p ≤0.05). When dividing our study population in groups of increasing breast PD, the DBT texture features appeared to be more discriminative, having regression lines with overall lower p-values, steeper slopes, and higher R2 estimates. Conclusion Although preliminary, our results suggest that DBT parenchymal texture analysis could provide more accurate characterization of breast density patterns, which could ultimately improve breast cancer risk estimation. PMID:19201357

  14. Lifetime risk of stroke and impact of hypertension: estimates from the adult health study in Hiroshima and Nagasaki.

    PubMed

    Takahashi, Ikuno; Geyer, Susan M; Nishi, Nobuo; Ohshita, Tomohiko; Takahashi, Tetsuya; Akahoshi, Masazumi; Fujiwara, Saeko; Kodama, Kazunori; Matsumoto, Masayasu

    2011-05-01

    Very few reports have been published on lifetime risk (LTR) of stroke by blood pressure (BP) group. This study included participants in the Radiation Effects Research Foundation Adult Health Study who have been followed up by biennial health examinations since 1958. We calculated the LTR of stroke for various BP-based groups among 7847 subjects who had not been diagnosed with stroke before the index age of 55 years using cumulative incidence analysis adjusting for competing risks. By 2003, 868 subjects had suffered stroke (512 (58.9%) were women and 542 (62.4%) experienced ischemic stroke). BP was a significant factor in determining risk of stroke for men and women, with distributions of cumulative risk for stroke significantly different across BP groups. The LTR of all-stroke for normotension (systolic BP/diastolic BP < 120/80 mm Hg), prehypertension (120-139/80-89 mm Hg), stage 1 hypertension (140-159/90-99 mm Hg) and stage 2 hypertension (> 160/100 mm Hg) were 13.8-16.9-25.8-25.8% in men and 16.0-19.9-24.0-30.5% in women, respectively (P < 0.001 among BP groups in both sexes). The estimates did not differ significantly (P = 0.16) between normotensive and prehypertensive subjects. One in five Japanese atomic bomb survivor subjects experienced stroke over their lifetime from the age of 55 years. Long-term stroke risks were elevated in those with hypertension (> 140/90 mm Hg) at any of the index ages of 45, 55, 65 and 75 years. PMID:21326305

  15. Risk factors for chronic undernutrition among children in India: Estimating relative importance, population attributable risk and fractions.

    PubMed

    Corsi, Daniel J; Mejía-Guevara, Iván; Subramanian, S V

    2016-05-01

    Nearly 40% of the world's stunted children live in India and the prevalence of undernutrition has been persistently high in recent decades. Given numerous available interventions for reducing undernutrition in children, it is not clear of the relative importance of each within a multifactorial framework. We assess the simultaneous contribution of 15 known risk factors for child chronic undernutrition in India. Data are from the 3rd Indian National Family Health Survey (NFHS-3), a nationally representative cross-sectional survey undertaken in 2005-2006. The study population consisted of children aged 6-59 months [n = 26,842 (stunting/low height-for-age), n = 27,483 (underweight/low weight-for-age)]. Risk factors examined for their association with undernutrition were: vitamin A supplementation, vaccination, use of iodized salt, household air quality, improved sanitary facilities, safe disposal of stools, improved drinking water, prevalence of infectious disease, initiation of breastfeeding, dietary diversity, age at marriage, maternal BMI, height, education, and household wealth. Age/sex-adjusted and multivariable adjusted effect sizes (odds ratios) were calculated for risk factors along with Population Attributable Risks (PAR) and Fractions (PAF) using logistic regression. In the mutually adjusted models, the five most important predictors of childhood stunting/underweight were short maternal stature, mother having no education, households in lowest wealth quintile, poor dietary diversity, and maternal underweight. These five factors had a combined PAR of 67.2% (95% CI: 63.3-70.7) and 69.7% (95% CI: 66.3-72.8) for stunting and underweight, respectively. The remaining factors were associated with a combined PAR of 11.7% (95% CI: 6.0-17.4) and 15.1% (95% CI: 8.9-21.3) for stunting and underweight, respectively. Implementing strategies focused on broader progress on social circumstances and infrastructural domains as well as investments in nutrition specific

  16. Assessing Changes in Socioemotional Adjustment across Early School Transitions--New National Scales for Children at Risk

    ERIC Educational Resources Information Center

    McDermott, Paul A.; Watkins, Marley W.; Rovine, Michael J.; Rikoon, Samuel H.

    2013-01-01

    This article reports the development and evidence for validity and application of the Adjustment Scales for Early Transition in Schooling (ASETS). Based on primary analyses of data from the Head Start Impact Study, a nationally representative sample (N = 3077) of randomly selected children from low-income households is configured to inform…

  17. Early Developmental and Psychosocial Risks and Longitudinal Behavioral Adjustment Outcomes for Preschool-Age Girls Adopted from China

    ERIC Educational Resources Information Center

    Tan, Tony Xing; Marfo, Kofi; Dedrick, Robert F.

    2010-01-01

    The central goal of this longitudinal study was to examine behavioral adjustment outcomes in a sample of preschool-age adopted Chinese girls. Research examining the effects of institutional deprivation on post-adoption behavioral outcomes for internationally adopted children has been constrained by the frequent unavailability of data on the…

  18. FY 2000 Buildings Energy Savings Estimates under Uncertainty: Developing Approaches for Incorporating Risk into Buildings Program Energy Efficiency Estimates

    SciTech Connect

    Anderson, Dave M.

    2002-11-18

    This report is one of two that re-examines the forecasted impact of individual programs currently within the Buildings Technology Program (BT) and the Weatherization and Intergovernmental Program (WIP) that appeared in the FY2000 Presidential Budget request. This report develops potential methods for allowing inherent risk to be captured in the program benefits analysis. Note that the FY2000 budget request was originally analyzed under the former Office of Building Technology, State and Community Programs (BTS), where BT and WIP were previously combined. Throughout the document, reference will be made to the predecessor of the BT and WIP programs, BTS, as FY2000 reflected that organization. A companion report outlines the effects of re-estimating the FY 2000 budget request based on overlaying program data from subsequent years, essentially revised out-year forecasts. That report shows that year-to-year long-term projections of primary energy savings can vary widely as models improve and programs change. Those point estimates are not influenced by uncertainty or risk. This report develops potential methods for allowing inherent risk to affect the benefits analysis via Monte Carlo simulation.

  19. 46 CFR 309.6 - Adjustments for condition, equipment, and other considerations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... OPERATIONS VALUES FOR WAR RISK INSURANCE § 309.6 Adjustments for condition, equipment, and other... of $50,000, an amount estimated by the Maritime Administration as the fair and reasonable value...

  20. 46 CFR 309.6 - Adjustments for condition, equipment, and other considerations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OPERATIONS VALUES FOR WAR RISK INSURANCE § 309.6 Adjustments for condition, equipment, and other... of $50,000, an amount estimated by the Maritime Administration as the fair and reasonable value...

  1. 46 CFR 309.6 - Adjustments for condition, equipment, and other considerations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... OPERATIONS VALUES FOR WAR RISK INSURANCE § 309.6 Adjustments for condition, equipment, and other... of $50,000, an amount estimated by the Maritime Administration as the fair and reasonable value...

  2. 46 CFR 309.6 - Adjustments for condition, equipment, and other considerations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OPERATIONS VALUES FOR WAR RISK INSURANCE § 309.6 Adjustments for condition, equipment, and other... of $50,000, an amount estimated by the Maritime Administration as the fair and reasonable value...

  3. Estimated Risk Level of Unified Stereotactic Body Radiation Therapy Dose Tolerance Limits for Spinal Cord.

    PubMed

    Grimm, Jimm; Sahgal, Arjun; Soltys, Scott G; Luxton, Gary; Patel, Ashish; Herbert, Scott; Xue, Jinyu; Ma, Lijun; Yorke, Ellen; Adler, John R; Gibbs, Iris C

    2016-04-01

    A literature review of more than 200 stereotactic body radiation therapy spine articles from the past 20 years found only a single article that provided dose-volume data and outcomes for each spinal cord of a clinical dataset: the Gibbs 2007 article (Gibbs et al, 2007(1)), which essentially contains the first 100 stereotactic body radiation therapy (SBRT) spine treatments from Stanford University Medical Center. The dataset is modeled and compared in detail to the rest of the literature review, which found 59 dose tolerance limits for the spinal cord in 1-5 fractions. We partitioned these limits into a unified format of high-risk and low-risk dose tolerance limits. To estimate the corresponding risk level of each limit we used the Gibbs 2007 clinical spinal cord dose-volume data for 102 spinal metastases in 74 patients treated by spinal radiosurgery. In all, 50 of the patients were previously irradiated to a median dose of 40Gy in 2-3Gy fractions and 3 patients developed treatment-related myelopathy. These dose-volume data were digitized into the dose-volume histogram (DVH) Evaluator software tool where parameters of the probit dose-response model were fitted using the maximum likelihood approach (Jackson et al, 1995(3)). Based on this limited dataset, for de novo cases the unified low-risk dose tolerance limits yielded an estimated risk of spinal cord injury of ≤1% in 1-5 fractions, and the high-risk limits yielded an estimated risk of ≤3%. The QUANTEC Dmax limits of 13Gy in a single fraction and 20Gy in 3 fractions had less than 1% risk estimated from this dataset, so we consider these among the low-risk limits. In the previously irradiated cohort, the estimated risk levels for 10 and 14Gy maximum cord dose limits in 5 fractions are 0.4% and 0.6%, respectively. Longer follow-up and more patients are required to improve the risk estimates and provide more complete validation. PMID:27000514

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

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

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

    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.

  6. A methodology for estimating risks associated with landslides of contaminated soil into rivers.

    PubMed

    Göransson, Gunnel; Norrman, Jenny; Larson, Magnus; Alén, Claes; Rosén, Lars

    2014-02-15

    Urban areas adjacent to surface water are exposed to soil movements such as erosion and slope failures (landslides). A landslide is a potential mechanism for mobilisation and spreading of pollutants. This mechanism is in general not included in environmental risk assessments for contaminated sites, and the consequences associated with contamination in the soil are typically not considered in landslide risk assessments. This study suggests a methodology to estimate the environmental risks associated with landslides in contaminated sites adjacent to rivers. The methodology is probabilistic and allows for datasets with large uncertainties and the use of expert judgements, providing quantitative estimates of probabilities for defined failures. The approach is illustrated by a case study along the river Göta Älv, Sweden, where failures are defined and probabilities for those failures are estimated. Failures are defined from a pollution perspective and in terms of exceeding environmental quality standards (EQSs) and acceptable contaminant loads. Models are then suggested to estimate probabilities of these failures. A landslide analysis is carried out to assess landslide probabilities based on data from a recent landslide risk classification study along the river Göta Älv. The suggested methodology is meant to be a supplement to either landslide risk assessment (LRA) or environmental risk assessment (ERA), providing quantitative estimates of the risks associated with landslide in contaminated sites. The proposed methodology can also act as a basis for communication and discussion, thereby contributing to intersectoral management solutions. From the case study it was found that the defined failures are governed primarily by the probability of a landslide occurring. The overall probabilities for failure are low; however, if a landslide occurs the probabilities of exceeding EQS are high and the probability of having at least a 10% increase in the contamination load

  7. Real-time estimation of the hospitalization fatality risk of influenza A(H1N1)pdm09 in Hong Kong.

    PubMed

    Wong, J Y; Wu, P; Lau, E H Y; Tsang, T K; Fang, V J; Ho, L-M; Cowling, B J

    2016-06-01

    During the early stage of an epidemic, timely and reliable estimation of the severity of infections are important for predicting the impact that the influenza viruses will have in the population. We obtained age-specific deaths and hospitalizations for patients with laboratory-confirmed H1N1pdm09 infections from June 2009 to December 2009 in Hong Kong. We retrospectively obtained the real-time estimates of the hospitalization fatality risk (HFR), using crude estimation or allowing for right-censoring for final status in some patients. Models accounting for right-censoring performed better than models without adjustments. The risk of deaths in hospitalized patients with confirmed H1N1pdm09 increased with age. Reliable estimates of the HFR could be obtained before the peak of the first wave of H1N1pdm09 in young and middle-aged adults but after the peak in the elderly. In the next influenza pandemic, timely estimation of the HFR will contribute to risk assessment and disease control. PMID:27125572

  8. Estimated human health risks of disposing of nonhazardous oil field waste in salt caverns

    SciTech Connect

    Tomasko, D.; Elcock, D.; Veil, J.

    1997-09-01

    Argonne National Laboratory (ANL) has completed an evaluation of the possibility that adverse human health effects (carcinogenic and noncarcinogenic) could result from exposure to contaminants released from nonhazardous oil field wastes (NOW) disposed in domal salt caverns. In this assessment, several steps were used to evaluate potential human health risks: identifying potential contaminants of concern, determining how humans could be exposed to these contaminants, assessing the contaminants` toxicities, estimating contaminant intakes, and, finally, calculating human cancer and noncancer risks.

  9. Science policy choices and the estimation of cancer risk associated with exposure to TCDD

    SciTech Connect

    Gough, M.

    1988-09-01

    United States regulatory agencies use no-threshold models for estimating carcinogenic risks. Other countries use no-threshold models for carcinogens that are genotoxic and threshold models for carcinogens that are not genotoxic, such as 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin). The U.S. Environmental Protection Agency has proposed a revision of the carcinogenic potency estimate for TCDD that is based on neither a threshold nor a no-threshold model; instead, it is a compromise between risk numbers generated by the two irreconcilably different models. This paper discusses the revision and its implications.

  10. Proteinuria and Reduced Estimated Glomerular Filtration Rate Independently Predict Risk for Acute Myocardial Infarction: Findings from a Population-Based Study in Keelung, Taiwan

    PubMed Central

    Chang, Shu-Hsuan; Tsai, Chia-Ti; Yen, Amy Ming-Fang; Lei, Meng-Huan; Chen, Hsiu-Hsi; Tseng, Chuen-Den

    2015-01-01

    Background The aim of this study was to evaluate the independent roles of proteinuria and reduced estimated glomerular filtration rate (GFR) in the development of acute myocardial infarction in a northern Taiwanese population. Methods We conducted a community-based prospective cohort study in Keelung, the northernmost county of Taiwan. A total of 63,129 subjects (63% women) ≥ 20 years of age who had no history of coronary heart disease were recruited and followed-up. Univariate and multivariate proportional hazards regression analysis was performed to assess the association between proteinuria and estimated GFR and the risk of acute myocardial infarction. Results There were 305 new cases of acute myocardial infarction (114 women and 191 men) documented during a four-year follow-up period. After adjustment of potential confounding covariates, heavier proteinuria (dipstick urinalysis reading 3+) and estimated GFR of less than 60 ml/min/1.73 m2 independently predicted increased risk of developing acute myocardial infarction. The adjusted hazard ratio (aHR) of heavier proteinuria for occurrence of acute myocardial infarction was 1.85 [95% confidence intervals (CI), 1.17-2.91, p < 0.01] (vs. the reference group: negative dipstick proteinuria). The aHR of estimated GFR of 30-59 ml/min/1.73 m2 for occurrence of acute myocardial infarction was 2.4 (95% CI, 1.31-4.38, p < 0.01) (vs. the reference group: estimated GFR ≥ 90 ml/ min/1.73 m2), and that of estimated GFR of 15-29 ml/min/1.73 m2 was 5.26 (95% CI, 2.26-12.26, p < 0.01). Conclusions We demonstrated that both heavier proteinuria and lower estimated GFR are significant independent predictors of developing future acute myocardial infarction in a northern Taiwanese population. PMID:27122856

  11. Examining the effects of air pollution composition on within region differences in PM2.5 mortality risk estimates

    EPA Science Inventory

    Multi-city population-based epidemiological studies have observed significant heterogeneity in both the magnitude and direction of city-specific risk estimates, but tended to focus on regional differences in PM2.5 mortality risk estimates. Interpreting differences in risk estimat...

  12. Estimation of flood risk for cultural heritage in an art city

    NASA Astrophysics Data System (ADS)

    Arrighi, Chiara; Brugioni, Marcello; Franceschini, Serena; Castelli, Fabio; Mazzanti, Bernardo

    2015-04-01

    Flood risk assessment in art cities poses many challenges for the presence of cultural heritage at risk, which is a damage category whose value is hardly monetizable. In fact, valuing cultural asset is a complex task, usually requiring more effort than a rough estimation of restoration costs. The lack of an adequate risk evaluation of the cultural asset may also lead to enormous difficulties and political problems for the accomplishment of the structural mitigation solutions. The aim of the work is to perform a first analysis of the risk to cultural heritage avoiding a full quantification of exposure. Here we present a case study of broad importance, which is the art city of Florence (Italy), affected by a devastating flood in 1966. In previous studies the estimated flood risk, neglecting damages to cultural heritage, was about 53 Mio€ /year. Nevertheless, Florence hosts 176 buildings officially classified as cultural heritage and thousands of paintings, sculptures and ancient books. Proceeding similarly to the commonly accepted flood risk assessment method, the annual expected loss in terms of cultural heritage/artworks is estimated.

  13. Social Risk and Protective Factors for African American Children's Academic Achievement and Adjustment during the Transition to Middle School

    ERIC Educational Resources Information Center

    Burchinal, Margaret R.; Roberts, Joanne E.; Zeisel, Susan A.; Rowley, Stephanie J.

    2008-01-01

    The transition to middle school is often marked by decreased academic achievement and increased emotional stress, and African American children exposed to social risk may be especially vulnerable during this transition. To identify mediators and protective factors, the authors related severity and timing of risk exposure to academic achievement…

  14. Estimate of Space Radiation-Induced Cancer Risks for International Space Station Orbits

    NASA Technical Reports Server (NTRS)

    Wu, Honglu; Atwell, William; Cucinotta, Francis A.; Yang, Chui-hsu

    1996-01-01

    Excess cancer risks from exposures to space radiation are estimated for various orbits of the International Space Station (ISS). Organ exposures are computed with the transport codes, BRYNTRN and HZETRN, and the computerized anatomical male and computerized anatomical female models. Cancer risk coefficients in the National Council on Radiation Protection and Measurements report No. 98 are used to generate lifetime excess cancer incidence and cancer mortality after a one-month mission to ISS. The generated data are tabulated to serve as a quick reference for assessment of radiation risk to astronauts on ISS missions.

  15. Estimate of Space Radiation-Induced Cancer Risks for International Space Station Orbits

    SciTech Connect

    Wu, H.; Atwell, W.; Cucinotta, F.A.; Yang, C.

    1996-03-01

    Excess cancer risks from exposures to space radiation are estimated for various orbits of the International Space Station (ISS). Organ exposures are computed with the transport codes, BRYNTRN and HZETRN, and the computerized anatomical male and computerized anatomical female models. Cancer risk coefficients in the National Council on Radiation Protection and Measurements report No. 98 are used to generate lifetime excess cancer incidence and cancer mortality after a one-month mission to ISS. The generated data are tabulated to serve as a quick reference for assessment of radiation risk to astronauts on ISS missions.

  16. Estimating cancer risk from dental cone-beam CT exposures based on skin dosimetry.

    PubMed

    Pauwels, Ruben; Cockmartin, Lesley; Ivanauskaité, Deimante; Urbonienė, Ausra; Gavala, Sophia; Donta, Catherine; Tsiklakis, Kostas; Jacobs, Reinhilde; Bosmans, Hilde; Bogaerts, Ria; Horner, Keith

    2014-07-21

    The aim of this study was to measure entrance skin doses on patients undergoing cone-beam computed tomography (CBCT) examinations, to establish conversion factors between skin and organ doses, and to estimate cancer risk from CBCT exposures. 266 patients (age 8-83) were included, involving three imaging centres. CBCT scans were acquired using the SCANORA 3D (Soredex, Tuusula, Finland) and NewTom 9000 (QR, Verona, Italy). Eight thermoluminescent dosimeters were attached to the patient's skin at standardized locations. Using previously published organ dose estimations on various CBCTs with an anthropomorphic phantom, correlation factors to convert skin dose to organ doses were calculated and applied to estimate patient organ doses. The BEIR VII age- and gender-dependent dose-risk model was applied to estimate the lifetime attributable cancer risk. For the SCANORA 3D, average skin doses over the eight locations varied between 484 and 1788 µGy. For the NewTom 9000 the range was between 821 and 1686 µGy for Centre 1 and between 292 and 2325 µGy for Centre 2. Entrance skin dose measurements demonstrated the combined effect of exposure and patient factors on the dose. The lifetime attributable cancer risk, expressed as the probability to develop a radiation-induced cancer, varied between 2.7 per million (age >60) and 9.8 per million (age 8-11) with an average of 6.0 per million. On average, the risk for female patients was 40% higher. The estimated radiation risk was primarily influenced by the age at exposure and the gender, pointing out the continuing need for justification and optimization of CBCT exposures, with a specific focus on children. PMID:24957710

  17. Estimating cancer risk from dental cone-beam CT exposures based on skin dosimetry

    NASA Astrophysics Data System (ADS)

    Pauwels, Ruben; Cockmartin, Lesley; Ivanauskaité, Deimante; Urbonienė, Ausra; Gavala, Sophia; Donta, Catherine; Tsiklakis, Kostas; Jacobs, Reinhilde; Bosmans, Hilde; Bogaerts, Ria; Horner, Keith; SEDENTEXCT Project Consortium, The

    2014-07-01

    The aim of this study was to measure entrance skin doses on patients undergoing cone-beam computed tomography (CBCT) examinations, to establish conversion factors between skin and organ doses, and to estimate cancer risk from CBCT exposures. 266 patients (age 8-83) were included, involving three imaging centres. CBCT scans were acquired using the SCANORA 3D (Soredex, Tuusula, Finland) and NewTom 9000 (QR, Verona, Italy). Eight thermoluminescent dosimeters were attached to the patient's skin at standardized locations. Using previously published organ dose estimations on various CBCTs with an anthropomorphic phantom, correlation factors to convert skin dose to organ doses were calculated and applied to estimate patient organ doses. The BEIR VII age- and gender-dependent dose-risk model was applied to estimate the lifetime attributable cancer risk. For the SCANORA 3D, average skin doses over the eight locations varied between 484 and 1788 µGy. For the NewTom 9000 the range was between 821 and 1686 µGy for Centre 1 and between 292 and 2325 µGy for Centre 2. Entrance skin dose measurements demonstrated the combined effect of exposure and patient factors on the dose. The lifetime attributable cancer risk, expressed as the probability to develop a radiation-induced cancer, varied between 2.7 per million (age >60) and 9.8 per million (age 8-11) with an average of 6.0 per million. On average, the risk for female patients was 40% higher. The estimated radiation risk was primarily influenced by the age at exposure and the gender, pointing out the continuing need for justification and optimization of CBCT exposures, with a specific focus on children.

  18. Estimation of the Optimal Statistical Quality Control Sampling Time Intervals Using a Residual Risk Measure

    PubMed Central

    Hatjimihail, Aristides T.

    2009-01-01

    Background An open problem in clinical chemistry is the estimation of the optimal sampling time intervals for the application of statistical quality control (QC) procedures that are based on the measurement of control materials. This is a probabilistic risk assessment problem that requires reliability analysis of the analytical system, and the estimation of the risk caused by the measurement error. Methodology/Principal Findings Assuming that the states of the analytical system are the reliability state, the maintenance state, the critical-failure modes and their combinations, we can define risk functions based on the mean time of the states, their measurement error and the medically acceptable measurement error. Consequently, a residual risk measure rr can be defined for each sampling time interval. The rr depends on the state probability vectors of the analytical system, the state transition probability matrices before and after each application of the QC procedure and the state mean time matrices. As optimal sampling time intervals can be defined those minimizing a QC related cost measure while the rr is acceptable. I developed an algorithm that estimates the rr for any QC sampling time interval of a QC procedure applied to analytical systems with an arbitrary number of critical-failure modes, assuming any failure time and measurement error probability density function for each mode. Furthermore, given the acceptable rr, it can estimate the optimal QC sampling time intervals. Conclusions/Significance It is possible to rationally estimate the optimal QC sampling time intervals of an analytical system to sustain an acceptable residual risk with the minimum QC related cost. For the optimization the reliability analysis of the analytical system and the risk analysis of the measurement error are needed. PMID:19513124

  19. An Evidenced-Based Approach for Estimating Decompression Sickness Risk in Aircraft Operations

    NASA Technical Reports Server (NTRS)

    Robinson, Ronald R.; Dervay, Joseph P.; Conkin, Johnny

    1999-01-01

    Estimating the risk of decompression Sickness (DCS) in aircraft operations remains a challenge, making the reduction of this risk through the development of operationally acceptable denitrogenation schedules difficult. In addition, the medical recommendations which are promulgated are often not supported by rigorous evaluation of the available data, but are instead arrived at by negotiation with the aircraft operations community, are adapted from other similar aircraft operations, or are based upon the opinion of the local medical community. We present a systematic approach for defining DCS risk in aircraft operations by analyzing the data available for a specific aircraft, flight profile, and aviator population. Once the risk of DCS in a particular aircraft operation is known, appropriate steps can be taken to reduce this risk to a level acceptable to the applicable aviation community. Using this technique will allow any aviation medical community to arrive at the best estimate of DCS risk for its specific mission and aviator population and will allow systematic reevaluation of the decisions regarding DCS risk reduction when additional data are available.

  20. Estimated risk from exposure to radon decay products in US homes

    SciTech Connect

    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 /sup 222/Rn concentrations averaging 55 Bq m/sup -3/ and having 2% of homes exceeding 300 Bq m/sup -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/sup -3/ or more for their lifetimes is estimated to exceed 2%, with risks from the homes with thousands of Bq m/sup -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.

  1. Estimation of Hypertension Risk from Lifestyle Factors and Health Profile: A Case Study

    PubMed Central

    2014-01-01

    Hypertension is a highly prevalent risk factor for cardiovascular disease and it can also lead to other diseases which seriously harm the human health. Screening the risks and finding a clinical model for estimating the risk of onset, maintenance, or the prognosis of hypertension are of great importance to the prevention or treatment of the disease, especially if the indicator can be derived from simple health profile. In this study, we investigate a chronic disease questionnaire data set of 6563 rural citizens in East China and find out a clinical signature that can assess the risk of hypertension easily and accurately. The signature achieves an accuracy of about 83% on the external test dataset, with an AUC of 0.91. Our study demonstrates that a combination of simple lifestyle features can sufficiently reflect the risk of hypertension onset. This finding provides potential guidance for disease prevention and control as well as development of home care and home-care technologies. PMID:25019099

  2. Quantitative assessment of the microbial risk of leafy greens from farm to consumption: preliminary framework, data, and risk estimates.

    PubMed

    Danyluk, Michelle D; Schaffner, Donald W

    2011-05-01

    This project was undertaken to relate what is known about the behavior of Escherichia coli O157:H7 under laboratory conditions and integrate this information to what is known regarding the 2006 E. coli O157:H7 spinach outbreak in the context of a quantitative microbial risk assessment. The risk model explicitly assumes that all contamination arises from exposure in the field. Extracted data, models, and user inputs were entered into an Excel spreadsheet, and the modeling software @RISK was used to perform Monte Carlo simulations. The model predicts that cut leafy greens that are temperature abused will support the growth of E. coli O157:H7, and populations of the organism may increase by as much a 1 log CFU/day under optimal temperature conditions. When the risk model used a starting level of -1 log CFU/g, with 0.1% of incoming servings contaminated, the predicted numbers of cells per serving were within the range of best available estimates of pathogen levels during the outbreak. The model predicts that levels in the field of -1 log CFU/g and 0.1% prevalence could have resulted in an outbreak approximately the size of the 2006 E. coli O157:H7 outbreak. This quantitative microbial risk assessment model represents a preliminary framework that identifies available data and provides initial risk estimates for pathogenic E. coli in leafy greens. Data gaps include retail storage times, correlations between storage time and temperature, determining the importance of E. coli O157:H7 in leafy greens lag time models, and validation of the importance of cross-contamination during the washing process. PMID:21549039

  3. Improved representation of diurnal variability of rainfall retrieved from the Tropical Rainfall Measurement Mission Microwave Imager adjusted Precipitation Estimation From Remotely Sensed Information Using Artificial Neural Networks (PERSIANN) system

    NASA Astrophysics Data System (ADS)

    Hong, Yang; Hsu, Kuo-Lin; Sorooshian, Soroosh; Gao, Xiaogang

    2005-03-01

    Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks (PERSIANN) is a satellite infrared-based algorithm that produces global estimates of rainfall at resolutions of 0.25° × 0.25° and a half-hour. In this study the model parameters of PERSIANN are routinely adjusted using coincident rainfall derived from the Tropical Rainfall Measurement Mission Microwave Imager (TMI). The impact of such an adjustment on capturing the diurnal variability of rainfall is examined for the Boreal summer of 2002. General evaluations of the PERSIANN rainfall estimates with/without TMI adjustment were conducted using U.S. daily gauge rainfall and nationwide radar network (weather surveillance radar) 1988 Doppler data. The diurnal variability of PERSIANN rainfall estimates with TMI adjustment is improved over those without TMI adjustment. In particular, the amounts of afternoon and morning maximums in rainfall diurnal cycles improved by 14.9% and 26%, respectively, and the original 2-3 hours of time lag in the phase of diurnal cycles improved by 1-2 hours. In addition, the rainfall estimate with TMI adjustment has higher correlation (0.75 versus 0.63) and reduced bias (+8% versus -11%) at monthly 0.25° × 0.25° resolution than that without TMI adjustment and consistently shows higher correlation (0.62 versus 0.51) and lower bias (+22% versus -30%) at daily 0.25° × 0.25° scale. This study provides evidence that the TMI, which measures instantaneous rain rates from the TRMM platform flying on a non-Sun-synchronous orbit, enables PERSIANN to capture more realistic diurnal variations of rainfall. This study also reveals the limitation of current satellite rainfall estimation techniques in retrieving the rainfall diurnal features and suggests that further investigation of precipitation generation in different periods of cloud life cycles might help resolve this limitation.

  4. A review of methods to estimate cause-specific mortality in presence of competing risks

    USGS Publications Warehouse

    Heisey, Dennis M.; Patterson, Brent R.

    2006-01-01

    Estimating cause-specific mortality is often of central importance for understanding the dynamics of wildlife populations. Despite such importance, methodology for estimating and analyzing cause-specific mortality has received little attention in wildlife ecology during the past 20 years. The issue of analyzing cause-specific, mutually exclusive events in time is not unique to wildlife. In fact, this general problem has received substantial attention in human biomedical applications within the context of biostatistical survival analysis. Here, we consider cause-specific mortality from a modern biostatistical perspective. This requires carefully defining what we mean by cause-specific mortality and then providing an appropriate hazard-based representation as a competing risks problem. This leads to the general solution of cause-specific mortality as the cumulative incidence function (CIF). We describe the appropriate generalization of the fully nonparametric staggered-entry Kaplan–Meier survival estimator to cause-specific mortality via the nonparametric CIF estimator (NPCIFE), which in many situations offers an attractive alternative to the Heisey–Fuller estimator. An advantage of the NPCIFE is that it lends itself readily to risk factors analysis with standard software for Cox proportional hazards model. The competing risks–based approach also clarifies issues regarding another intuitive but erroneous "cause-specific mortality" estimator based on the Kaplan–Meier survival estimator and commonly seen in the life sciences literature.

  5. Prevalence Estimates of Health Risk Behaviors of Immigrant Latino Men Who Have Sex with Men

    ERIC Educational Resources Information Center

    Rhodes, Scott D.; McCoy, Thomas P.; Hergenrather, Kenneth C.; Vissman, Aaron T.; Wolfson, Mark; Alonzo, Jorge; Bloom, Fred R.; Alegria-Ortega, Jose; Eng, Eugenia

    2012-01-01

    Purpose: Little is known about the health status of rural immigrant Latino men who have sex with men (MSM). These MSM comprise a subpopulation that tends to remain "hidden" from both researchers and practitioners. This study was designed to estimate the prevalence of tobacco, alcohol, and drug use, and sexual risk behaviors of Latino MSM living in…

  6. RISK ESTIMATES FOR DETERMINISTIC HEALTH EFFECTS OF INHALED WEAPONS GRADE PLUTONIUM

    EPA Science Inventory

    Risk estimates for deterministic effects of inhaled weapons-grade plutonium (WG Pu) are needed to evaluate potential serious harm to: (1) U. S. Department of Energy nuclear workers from accidental or other work-place releases of WG Pu; and (2) the public from terrorist actions re...

  7. EVALUATION AND ESTIMATION OF POTENTIAL CARCINOGENIC RISKS OF POLYNUCLEAR AROMATIC HYDROCARBONS (PAH)

    EPA Science Inventory

    The evaluation and estimation of the potential risk of human exposures to a hazardous substance requires the analysis of all relevant data to answer two questions (1) does the agent cause the effect; (2) what is the relationship between dose (exposure) and incidence of the effect...

  8. Silica exposure and silicosis among Ontario hardrock miners: III. Analysis and risk estimates.

    PubMed

    Muir, D C; Julian, J A; Shannon, H S; Verma, D K; Sebestyen, A; Bernholz, C D

    1989-01-01

    An epidemiological investigation was undertaken to determine the relationship between silicosis in hardrock miners in Ontario and cumulative exposure to silica (free crystalline silica--alpha quartz) dust. This report describes the analytic method and presents the risk estimates. PMID:2750748

  9. ESTIMATING THE RISK OF LUNG CANCER FROM INHALATION OF RADON DAUGHTERS INDOORS: REVIEW AND EVALUATION

    EPA Science Inventory

    A review of the dosimetric models and epidemiological studies with regard to the relation between indoor radon exposure and lung cancer indicates that the Working Level is an appropriate unit for indoor radon exposure; that the uncertainty in applying risk estimates derived from ...

  10. Challenges in Obtaining Estimates of the Risk of Tuberculosis Infection During Overseas Deployment.

    PubMed

    Mancuso, James D; Geurts, Mia

    2015-12-01

    Estimates of the risk of tuberculosis (TB) infection resulting from overseas deployment among U.S. military service members have varied widely, and have been plagued by methodological problems. The purpose of this study was to estimate the incidence of TB infection in the U.S. military resulting from deployment. Three populations were examined: 1) a unit of 2,228 soldiers redeploying from Iraq in 2008, 2) a cohort of 1,978 soldiers followed up over 5 years after basic training at Fort Jackson in 2009, and 3) 6,062 participants in the 2011-2012 National Health and Nutrition Examination Survey (NHANES). The risk of TB infection in the deployed population was low-0.6% (95% confidence interval [CI]: 0.1-2.3%)-and was similar to the non-deployed population. The prevalence of latent TB infection (LTBI) in the U.S. population was not significantly different among deployed and non-deployed veterans and those with no military service. The limitations of these retrospective studies highlight the challenge in obtaining valid estimates of risk using retrospective data and the need for a more definitive study. Similar to civilian long-term travelers, risks for TB infection during deployment are focal in nature, and testing should be targeted to only those at increased risk. PMID:26416114

  11. Statistical Risk Estimation for Communication System Design: Results of the HETE-2 Test Case

    NASA Astrophysics Data System (ADS)

    Babuscia, A.; Cheung, K.-M.

    2014-05-01

    The Statistical Risk Estimation (SRE) technique described in this article is a methodology to quantify the likelihood that the major design drivers of mass and power of a space system meet the spacecraft and mission requirements and constraints through the design and development lifecycle. The SRE approach addresses the long-standing challenges of small sample size and unclear evaluation path of a space system, and uses a combination of historical data and expert opinions to estimate risk. Although the methodology is applicable to the entire spacecraft, this article is focused on a specific subsystem: the communication subsystem. Using this approach, the communication system designers will be able to evaluate and to compare different communication architectures in a risk trade-off perspective. SRE was introduced in two previous papers. This article aims to present additional results of the methodology by adding a new test case from a university mission, the High-Energy Transient Experiment (HETE)-2. The results illustrate the application of SRE to estimate the risks of exceeding constraints in mass and power, hence providing crucial risk information to support a project's decision on requirements rescope and/or system redesign.

  12. Hip fracture risk estimation based on principal component analysis of QCT atlas: a preliminary study

    NASA Astrophysics Data System (ADS)

    Li, Wenjun; Kornak, John; Harris, Tamara; Lu, Ying; Cheng, Xiaoguang; Lang, Thomas

    2009-02-01

    We aim to capture and apply 3-dimensional bone fragility features for fracture risk estimation. Using inter-subject image registration, we constructed a hip QCT atlas comprising 37 patients with hip fractures and 38 age-matched controls. In the hip atlas space, we performed principal component analysis to identify the principal components (eigen images) that showed association with hip fracture. To develop and test a hip fracture risk model based on the principal components, we randomly divided the 75 QCT scans into two groups, one serving as the training set and the other as the test set. We applied this model to estimate a fracture risk index for each test subject, and used the fracture risk indices to discriminate the fracture patients and controls. To evaluate the fracture discrimination efficacy, we performed ROC analysis and calculated the AUC (area under curve). When using the first group as the training group and the second as the test group, the AUC was 0.880, compared to conventional fracture risk estimation methods based on bone densitometry, which had AUC values ranging between 0.782 and 0.871. When using the second group as the training group, the AUC was 0.839, compared to densitometric methods with AUC values ranging between 0.767 and 0.807. Our results demonstrate that principal components derived from hip QCT atlas are associated with hip fracture. Use of such features may provide new quantitative measures of interest to osteoporosis.

  13. Partial covariate adjusted regression

    PubMed Central

    Şentürk, Damla; Nguyen, Danh V.

    2008-01-01

    Covariate adjusted regression (CAR) is a recently proposed adjustment method for regression analysis where both the response and predictors are not directly observed (Şentürk and Müller, 2005). The available data has been distorted by unknown functions of an observable confounding covariate. CAR provides consistent estimators for the coefficients of the regression between the variables of interest, adjusted for the confounder. We develop a broader class of partial covariate adjusted regression (PCAR) models to accommodate both distorted and undistorted (adjusted/unadjusted) predictors. The PCAR model allows for unadjusted predictors, such as age, gender and demographic variables, which are common in the analysis of biomedical and epidemiological data. The available estimation and inference procedures for CAR are shown to be invalid for the proposed PCAR model. We propose new estimators and develop new inference tools for the more general PCAR setting. In particular, we establish the asymptotic normality of the proposed estimators and propose consistent estimators of their asymptotic variances. Finite sample properties of the proposed estimators are investigated using simulation studies and the method is also illustrated with a Pima Indians diabetes data set. PMID:20126296

  14. Quantitative microbial risk assessment combined with hydrodynamic modelling to estimate the public health risk associated with bathing after rainfall events.

    PubMed

    Eregno, Fasil Ejigu; Tryland, Ingun; Tjomsland, Torulv; Myrmel, Mette; Robertson, Lucy; Heistad, Arve

    2016-04-01

    This study investigated the public health risk from exposure to infectious microorganisms at Sandvika recreational beaches, Norway and dose-response relationships by combining hydrodynamic modelling with Quantitative Microbial Risk Assessment (QMRA). Meteorological and hydrological data were collected to produce a calibrated hydrodynamic model using Escherichia coli as an indicator of faecal contamination. Based on average concentrations of reference pathogens (norovirus, Campylobacter, Salmonella, Giardia and Cryptosporidium) relative to E. coli in Norwegian sewage from previous studies, the hydrodynamic model was used for simulating the concentrations of pathogens at the local beaches during and after a heavy rainfall event, using three different decay rates. The simulated concentrations were used as input for QMRA and the public health risk was estimated as probability of infection from a single exposure of bathers during the three consecutive days after the rainfall event. The level of risk on the first day after the rainfall event was acceptable for the bacterial and parasitic reference pathogens, but high for the viral reference pathogen at all beaches, and severe at Kalvøya-small and Kalvøya-big beaches, supporting the advice of avoiding swimming in the day(s) after heavy rainfall. The study demonstrates the potential of combining discharge-based hydrodynamic modelling with QMRA in the context of bathing water as a tool to evaluate public health risk and support beach management decisions. PMID:26802355

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Behavioral adjustment to avian flu in Europe during spring 2006: the roles of knowledge and proximity to risk.

    PubMed

    Rudisill, Caroline; Costa-Font, Joan; Mossialos, Elias

    2012-10-01

    The threat of a widespread avian flu influenza outbreak represented a significant public health challenge for the European region during late 2005 and early 2006. Little is known, however, about how individuals learn about new global-level health risks, especially influenza outbreaks. We empirically test the hypothesis that knowledge about and geographic proximity to avian flu play a role in individuals' consumption behavior regarding this health risk. This article employs Eurobarometer survey data collected in spring 2006 to examine how Europeans (from 27 European Union countries plus Croatia and Turkey) altered their consumption of poultry, eggs and egg-based products during the virus' emergence in Europe. Our findings are consistent with the hypothesis that behavioral change indeed depends on proximity to those risks. Significant differences emerged between individuals' likelihood of behavioral change in countries where avian flu had been found in humans either in individuals' countries of residence or in bordering countries. Furthermore, we find that those who were more knowledgeable about avian flu risks were less likely to have reduced their consumption of poultry, eggs or egg-related products in the spring of 2006 compared to six months prior. Yet, the influence knowledge has on consumption behavior is found to change depending on proximity to avian flu risks. These findings have implications for our larger understanding of how individuals alter their behavior in the face of new health risks. PMID:22835921

  17. Effect of recent changes in atomic bomb survivor dosimetry on cancer mortality risk estimates.

    PubMed

    Preston, Dale L; Pierce, Donald A; Shimizu, Yukiko; Cullings, Harry M; Fujita, Shoichiro; Funamoto, Sachiyo; Kodama, Kazunori

    2004-10-01

    The Radiation Effects Research Foundation has recently implemented a new dosimetry system, DS02, to replace the previous system, DS86. This paper assesses the effect of the change on risk estimates for radiation-related solid cancer and leukemia mortality. The changes in dose estimates were smaller than many had anticipated, with the primary systematic change being an increase of about 10% in gamma-ray estimates for both cities. In particular, an anticipated large increase of the neutron component in Hiroshima for low-dose survivors did not materialize. However, DS02 improves on DS86 in many details, including the specifics of the radiation released by the bombs and the effects of shielding by structures and terrain. The data used here extend the last reported follow-up for solid cancers by 3 years, with a total of 10,085 deaths, and extends the follow-up for leukemia by 10 years, with a total of 296 deaths. For both solid cancer and leukemia, estimated age-time patterns and sex difference are virtually unchanged by the dosimetry revision. The estimates of solid-cancer radiation risk per sievert and the curvilinear dose response for leukemia are both decreased by about 8% by the dosimetry revision, due to the increase in the gamma-ray dose estimates. The apparent shape of the dose response is virtually unchanged by the dosimetry revision, but for solid cancers, the additional 3 years of follow-up has some effect. In particular, there is for the first time a statistically significant upward curvature for solid cancer on the restricted dose range 0-2 Sv. However, the low-dose slope of a linear-quadratic fit to that dose range should probably not be relied on for risk estimation, since that is substantially smaller than the linear slopes on ranges 0-1 Sv, 0-0.5 Sv, and 0- 0.25 Sv. Although it was anticipated that the new dosimetry system might reduce some apparent dose overestimates for Nagasaki factory workers, this did not materialize, and factory workers have

  18. Estimates of Prevalence and Risk Associated with Inattention and Distraction Based Upon In Situ Naturalistic Data

    PubMed Central

    Dingus, Thomas A.

    2014-01-01

    By using in situ naturalistic driving data, estimates of prevalence and risk can be made regarding driver populations’ secondary task distractions and crash rates. Through metadata analysis, three populations of drivers (i.e., adult light vehicle, teenaged light vehicle, and adult heavy vehicle) were compared regarding frequency of secondary task behavior and the associated risk for safety-critical incidents. Relative risk estimates provide insight into the risk associated with engaging in a single task. When such risk is considered in combination with frequency of use, it sheds additional light on those secondary tasks that create the greatest overall risk to driving safety. The results show that secondary tasks involving manual typing, texting, dialing, reaching for an object, or reading are dangerous for all three populations. Additionally, novice teen drivers have difficulty in several tasks that the other two populations do not, including eating and external distractions. Truck drivers also perform a number of risky “mobile office” types of tasks, including writing, not seen in the other populations. Implications are described for policy makers and designers of in-vehicle and nomadic, portable systems. PMID:24776227

  19. Estimating risk during showering exposure to VOCs of workers in a metal-degreasing facility.

    PubMed

    Franco, Amaya; Costoya, Miguel Angel; Roca, Enrique

    2007-04-01

    The incremental risk of workers in a metal-degreasing facility exposed to volatile organic compounds (VOCs) present in the water supply during showering was estimated. A probabilistic and worst-case approach using specific-site concentration data and a generalized multipathway exposure model was applied. Estimates of hazard index and lifetime cancer risk were analyzed for each chemical and each route of exposure (inhalation and dermal absorption). The results showed that dermal exposure to trichloroethylene (TCE) and tetrachloroethylene (perchloroethylene, PCE) represented the main contribution to total risk. Although the inhalation route did not produce significant exposure, it was mainly influenced by the liquid flow rate of the shower. Lower values of this parameter during showering resulted in a significant reduction of both carcinogenic and noncarcinogenic risk, while decreasing water temperature produced a minimal effect on exposure by this pathway. The results obtained in the present study indicated that significant exposures of workers may be produced during showering in metal degreasing installations where releases to water of VOCs occur. A sensitivity analysis was developed for investigating the effect of scenario parameters on exposure. Although site-specific data were employed, the exposure of workers was assessed in a model scenario and thus the quantification of risk is associated with uncertainty. Considering that occupational exposure to organic solvents of workers in metal-degreasing facilities may also be significant, risk assessment must be included in the planning of this kind of industrial installation. PMID:17365617

  20. Estimates of auditory risk from outdoor impulse noise. II: Civilian firearms.

    PubMed

    Flamme, Gregory A; Wong, Adam; Liebe, Kevin; Lynd, James

    2009-01-01

    Firearm impulses are common noise exposures in the United States. This study records, describes and analyzes impulses produced outdoors by civilian firearms with respect to the amount of auditory risk they pose to the unprotected listener under various listening conditions. Risk estimates were obtained using three contemporary damage risk criteria (DRC) including a waveform parameter-based approach (peak SPL and B-duration), an energy-based criterion (A-weighted SEL and equivalent continuous level) and a physiological model (AHAAH). Results from these DRC were converted into a number of maximum permissible unprotected exposures to facilitate interpretation. Acoustic characteristics of firearm impulses differed substantially across guns, ammunition, and microphone location. The type of gun, ammunition and the microphone location all significantly affected estimates of auditory risk from firearms. Vast differences in maximum permissible exposures were observed; the rank order of the differences varied with the source of the impulse. Unprotected exposure to firearm noise is not recommended, but people electing to fire a gun without hearing protection should be advised to minimize auditory risk through careful selection of ammunition and shooting environment. Small-caliber guns with long barrels and guns loaded with the least powerful ammunition tend to be associated with the least auditory risk. PMID:19805933

  1. The Prognostic Value of Family History for the Estimation of Cardiovascular Mortality Risk in Men: Results from a Long-Term Cohort Study in Lithuania

    PubMed Central

    Tamosiunas, Abdonas; Radisauskas, Ricardas; Klumbiene, Jurate; Bernotiene, Gailute; Petkeviciene, Janina; Luksiene, Dalia; Virviciute, Dalia; Malinauskiene, Vilija; Vikhireva, Olga; Grabauskas, Vilius

    2015-01-01

    Aim To evaluate the additional prognostic value of family history for the estimation of cardiovascular (CVD) mortality risk in middle-aged urban Lithuanian men. Methods The association between family history of CVD and the risk of CVD mortality was examined in a population-based cohort of 6,098 men enrolled during 1972–1974 and 1976–1980 in Kaunas, Lithuania. After up to 40 years of follow-up, 2,272 deaths from CVD and 1,482 deaths from coronary heart disease (CHD) were identified. Multivariate Cox proportional hazards models were used to estimate hazard ratios (HR) for CVD and CHD mortality. Results After adjustment for traditional CVD risk factors, the HR for CVD mortality was 1.24 (95% CI 1.09–1.42) and for CHD mortality 1.20 (1.02–1.42) in men with first-degree relatives having a history of myocardial infarction (MI), compared to men without positive family history. A significant effect on the risk of CVD and CHD mortality was also observed for the family history of sudden cardiac death and any CVD. Addition of family history of MI, sudden death, and any CVD to traditional CVD risk factors demonstrated modest improvement in the performance of Cox models for CVD and CHD mortality. Conclusions Family history of CVD is associated with a risk of CVD and CHD mortality significantly and independently of other risk factors in a middle-aged male population. Addition of family history to traditional CVD risk factors improves the prediction of CVD mortality and could be used for identification of high-risk individuals. PMID:26630455

  2. Estimating Risks of Heat Strain by Age and Sex: A Population-Level Simulation Model

    PubMed Central

    Glass, Kathryn; Tait, Peter W.; Hanna, Elizabeth G.; Dear, Keith

    2015-01-01

    Individuals living in hot climates face health risks from hyperthermia due to excessive heat. Heat strain is influenced by weather exposure and by individual characteristics such as age, sex, body size, and occupation. To explore the population-level drivers of heat strain, we developed a simulation model that scales up individual risks of heat storage (estimated using Myrup and Morgan’s man model “MANMO”) to a large population. Using Australian weather data, we identify high-risk weather conditions together with individual characteristics that increase the risk of heat stress under these conditions. The model identifies elevated risks in children and the elderly, with females aged 75 and older those most likely to experience heat strain. Risk of heat strain in males does not increase as rapidly with age, but is greatest on hot days with high solar radiation. Although cloudy days are less dangerous for the wider population, older women still have an elevated risk of heat strain on hot cloudy days or when indoors during high temperatures. Simulation models provide a valuable method for exploring population level risks of heat strain, and a tool for evaluating public health and other government policy interventions. PMID:25993102

  3. Cancer risk estimation in Digital Breast Tomosynthesis using GEANT4 Monte Carlo simulations and voxel phantoms.

    PubMed

    Ferreira, P; Baptista, M; Di Maria, S; Vaz, P

    2016-05-01

    The aim of this work was to estimate the risk of radiation induced cancer following the Portuguese breast screening recommendations for Digital Mammography (DM) when applied to Digital Breast Tomosynthesis (DBT) and to evaluate how the risk to induce cancer could influence the energy used in breast diagnostic exams. The organ doses were calculated by Monte Carlo simulations using a female voxel phantom and considering the acquisition of 25 projection images. Single organ cancer incidence risks were calculated in order to assess the total effective radiation induced cancer risk. The screening strategy techniques considered were: DBT in Cranio-Caudal (CC) view and two-view DM (CC and Mediolateral Oblique (MLO)). The risk of cancer incidence following the Portuguese screening guidelines (screening every two years in the age range of 50-80years) was calculated by assuming a single CC DBT acquisition view as standalone screening strategy and compared with two-view DM. The difference in the total effective risk between DBT and DM is quite low. Nevertheless in DBT an increase of risk for the lung is observed with respect to DM. The lung is also the organ that is mainly affected when non-optimal beam energy (in terms of image quality and absorbed dose) is used instead of an optimal one. The use of non-optimal energies could increase the risk of lung cancer incidence by a factor of about 2. PMID:27133140

  4. Estimates of Commercial Population at High Risk for Cardiovascular Events: Impact of Aggressive Cholesterol Reduction

    PubMed Central

    Fitch, Kathryn; Goldberg, Sara W.; Iwasaki, Kosuke; Pyenson, Bruce S.; Kuznik, Andreas; Solomon, Henry A.

    2009-01-01

    Objectives To model the financial and health outcomes impact of intensive statin therapy compared with usual care in a high-risk working-age population (actively employed, commercially insured health plan members and their adult dependents). The target population consists of working-age people who are considered high-risk for cardiovascular disease events because of a history of coronary heart disease. Study Design Three-year event forecast for a sample population generated from the National Health and Nutrition Examination Survey data. Methods Using Framingham risk scoring system, the probability of myocardial infarction or stroke events was calculated for a representative sample population, ages 35 to 69 years, of people at high risk for cardiovascular disease, with a history of coronary heart disease. The probability of events for each individual was used to project the number of events expected to be generated for this population. Reductions in cardiovascular and stroke events reported in clinical trials with aggressive statin therapy were applied to these cohorts. We used medical claims data to model the cohorts' event costs. All results are adjusted to reflect the demographics of a typical working-age population. Results The high-risk cohort (those with coronary heart disease) comprises 4% of the 35- to 69-year-old commercially insured population but generates 22% of the risk for coronary heart disease and stroke. Reduced event rates associated with intensive statin therapy yielded a $58 mean medical cost reduction per treated person per month; a typical payer cost for a 30-day supply of intensive statin therapy is approximately $57. Conclusions Aggressive low-density lipoprotein cholesterol–lowering therapy for working-age people at high risk for cardiovascular events and with a history of heart disease appears to have a significant potential to reduce the rate of clinical events and is cost-neutral for payers. PMID:25126293

  5. Better contralateral breast cancer risk estimation and alternative options to contralateral prophylactic mastectomy

    PubMed Central

    Davies, Kalatu R; Cantor, Scott B; Brewster, Abenaa M

    2015-01-01

    The incidence of contralateral prophylactic mastectomy (CPM) has increased among women with breast cancer, despite uncertain survival benefit and a declining incidence of contralateral breast cancer (CBC). Patient-related reasons for undergoing CPM include an overestimation of the risk of CBC, increased cancer worry, and a desire to improve survival. We summarize the existing literature on CBC risk and outcomes and the clinical benefit of CPM among women with unilateral breast cancer who have a low-to-moderate risk of developing a secondary cancer in the contralateral breast. Published studies were retrieved from the MEDLINE database with the keywords “contralateral breast cancer” and “contralateral prophylactic mastectomy”. These include observational studies, clinical trials, survival analyses, and decision models examining the risk of CBC, the clinical and psychosocial effects of CPM, and other treatment strategies to reduce CBC risk. Studies that have evaluated CBC risk estimate it to be approximately 0.5% annually on average. Patient-related factors associated with an increased risk of CBC include carriers of BRCA1/2 mutations, young age at breast cancer, and strong family history of breast cancer in the absence of a BRCA1/2 mutation. Although CPM reduces the risk of CBC by approximately 94%, it may not provide a significant gain in overall survival and there is conflicting evidence that it improves disease-free survival among women with breast cancer regardless of estrogen receptor (ER) status. Therefore, alternative strategies such as the use of tamoxifen or aromatase inhibitors, which reduce the risk of CBC by approximately 50%, should be encouraged for eligible women with ER-positive breast cancers. Future research is needed to evaluate the impact of decision and educational tools that can be used for personalized counseling of patients regarding their CBC risk, the uncertain role of CPM, and alternative CBC risk reduction strategies. PMID:25678823

  6. Better contralateral breast cancer risk estimation and alternative options to contralateral prophylactic mastectomy.

    PubMed

    Davies, Kalatu R; Cantor, Scott B; Brewster, Abenaa M

    2015-01-01

    The incidence of contralateral prophylactic mastectomy (CPM) has increased among women with breast cancer, despite uncertain survival benefit and a declining incidence of contralateral breast cancer (CBC). Patient-related reasons for undergoing CPM include an overestimation of the risk of CBC, increased cancer worry, and a desire to improve survival. We summarize the existing literature on CBC risk and outcomes and the clinical benefit of CPM among women with unilateral breast cancer who have a low-to-moderate risk of developing a secondary cancer in the contralateral breast. Published studies were retrieved from the MEDLINE database with the keywords "contralateral breast cancer" and "contralateral prophylactic mastectomy". These include observational studies, clinical trials, survival analyses, and decision models examining the risk of CBC, the clinical and psychosocial effects of CPM, and other treatment strategies to reduce CBC risk. Studies that have evaluated CBC risk estimate it to be approximately 0.5% annually on average. Patient-related factors associated with an increased risk of CBC include carriers of BRCA1/2 mutations, young age at breast cancer, and strong family history of breast cancer in the absence of a BRCA1/2 mutation. Although CPM reduces the risk of CBC by approximately 94%, it may not provide a significant gain in overall survival and there is conflicting evidence that it improves disease-free survival among women with breast cancer regardless of estrogen receptor (ER) status. Therefore, alternative strategies such as the use of tamoxifen or aromatase inhibitors, which reduce the risk of CBC by approximately 50%, should be encouraged for eligible women with ER-positive breast cancers. Future research is needed to evaluate the impact of decision and educational tools that can be used for personalized counseling of patients regarding their CBC risk, the uncertain role of CPM, and alternative CBC risk reduction strategies. PMID:25678823

  7. Vertebral Strength and Estimated Fracture Risk Across the BMI Spectrum in Women.

    PubMed

    Bachmann, Katherine N; Bruno, Alexander G; Bredella, Miriam A; Schorr, Melanie; Lawson, Elizabeth A; Gill, Corey M; Singhal, Vibha; Meenaghan, Erinne; Gerweck, Anu V; Eddy, Kamryn T; Ebrahimi, Seda; Koman, Stuart L; Greenblatt, James M; Keane, Robert J; Weigel, Thomas; Dechant, Esther; Misra, Madhusmita; Klibanski, Anne; Bouxsein, Mary L; Miller, Karen K

    2016-02-01

    Somewhat paradoxically, fracture risk, which depends on applied loads and bone strength, is elevated in both anorexia nervosa and obesity at certain skeletal sites. Factor-of-risk (Φ), the ratio of applied load to bone strength, is a biomechanically based method to estimate fracture risk; theoretically, higher Φ reflects increased fracture risk. We estimated vertebral strength (linear combination of integral volumetric bone mineral density [Int.vBMD] and cross-sectional area from quantitative computed tomography [QCT]), vertebral compressive loads, and Φ at L4 in 176 women (65 anorexia nervosa, 45 lean controls, and 66 obese). Using biomechanical models, applied loads were estimated for: 1) standing; 2) arms flexed 90°, holding 5 kg in each hand (holding); 3) 45° trunk flexion, 5 kg in each hand (lifting); 4) 20° trunk right lateral bend, 10 kg in right hand (bending). We also investigated associations of Int.vBMD and vertebral strength with lean mass (from dual-energy X-ray absorptiometry [DXA]) and visceral adipose tissue (VAT, from QCT). Women with anorexia nervosa had lower, whereas obese women had similar, Int.vBMD and estimated vertebral strength compared with controls. Vertebral loads were highest in obesity and lowest in anorexia nervosa for standing, holding, and lifting (p < 0.0001) but were highest in anorexia nervosa for bending (p < 0.02). Obese women had highest Φ for standing and lifting, whereas women with anorexia nervosa had highest Φ for bending (p < 0.0001). Obese and anorexia nervosa subjects had higher Φ for holding than controls (p < 0.03). Int.vBMD and estimated vertebral strength were associated positively with lean mass (R = 0.28 to 0.45, p ≤ 0.0001) in all groups combined and negatively with VAT (R = -[0.36 to 0.38], p < 0.003) within the obese group. Therefore, women with anorexia nervosa had higher estimated vertebral fracture risk (Φ) for holding and bending because of inferior vertebral strength. Despite similar

  8. A Methodological Approach to Small Area Estimation for the Behavioral Risk Factor Surveillance System

    PubMed Central

    Xu, Fang; Wallace, Robyn C.; Garvin, William; Greenlund, Kurt J.; Bartoli, William; Ford, Derek; Eke, Paul; Town, G. Machell

    2016-01-01

    Public health researchers have used a class of statistical methods to calculate prevalence estimates for small geographic areas with few direct observations. Many researchers have used Behavioral Risk Factor Surveillance System (BRFSS) data as a basis for their models. The aims of this study were to 1) describe a new BRFSS small area estimation (SAE) method and 2) investigate the internal and external validity of the BRFSS SAEs it produced. The BRFSS SAE method uses 4 data sets (the BRFSS, the American Community Survey Public Use Microdata Sample, Nielsen Claritas population totals, and the Missouri Census Geographic Equivalency File) to build a single weighted data set. Our findings indicate that internal and external validity tests were successful across many estimates. The BRFSS SAE method is one of several methods that can be used to produce reliable prevalence estimates in small geographic areas. PMID:27418213

  9. A Methodological Approach to Small Area Estimation for the Behavioral Risk Factor Surveillance System.

    PubMed

    Pierannunzi, Carol; Xu, Fang; Wallace, Robyn C; Garvin, William; Greenlund, Kurt J; Bartoli, William; Ford, Derek; Eke, Paul; Town, G Machell

    2016-01-01

    Public health researchers have used a class of statistical methods to calculate prevalence estimates for small geographic areas with few direct observations. Many researchers have used Behavioral Risk Factor Surveillance System (BRFSS) data as a basis for their models. The aims of this study were to 1) describe a new BRFSS small area estimation (SAE) method and 2) investigate the internal and external validity of the BRFSS SAEs it produced. The BRFSS SAE method uses 4 data sets (the BRFSS, the American Community Survey Public Use Microdata Sample, Nielsen Claritas population totals, and the Missouri Census Geographic Equivalency File) to build a single weighted data set. Our findings indicate that internal and external validity tests were successful across many estimates. The BRFSS SAE method is one of several methods that can be used to produce reliable prevalence estimates in small geographic areas. PMID:27418213

  10. Cumulative Socioeconomic Status Risk, Allostatic Load, and Adjustment: A Prospective Latent Profile Analysis with Contextual and Genetic Protective Factors

    ERIC Educational Resources Information Center

    Brody, Gene H.; Yu, Tianyi; Chen, Yi-Fu; Kogan, Steven M.; Evans, Gary W.; Beach, Steven R. H.; Windle, Michael; Simons, Ronald L.; Gerrard, Meg; Gibbons, Frederick X.; Philibert, Robert A.

    2013-01-01

    The health disparities literature has identified a common pattern among middle-aged African Americans that includes high rates of chronic disease along with low rates of psychiatric disorders despite exposure to high levels of cumulative socioeconomic status (SES) risk. The current study was designed to test hypotheses about the developmental…

  11. Acculturation and Adjustment in Latino Adolescents: How Cultural Risk Factors and Assets Influence Multiple Domains of Adolescent Mental Health

    ERIC Educational Resources Information Center

    Smokowski, Paul; Buchanan, Rachel L.; Bacallao, Martica L.

    2009-01-01

    The purpose of this study was to examine the relationships among risk factors, cultural assets, and Latino adolescent mental health outcomes. We extend past research by using a longitudinal design and evaluating direct and moderated acculturation effects across a range of internalizing, externalizing, and academic engagement outcomes. The sample…

  12. Risk estimates for deterministic health effects of inhaled weapons grade plutonium.

    PubMed

    Scott, Bobby R; Peterson, Vern L

    2003-09-01

    Risk estimates for deterministic effects of inhaled weapons-grade plutonium (WG Pu) are needed to evaluate potential serious harm to (1) U.S. Department of Energy nuclear workers from accidental or other work-place releases of WG Pu; and (2) the public from terrorist actions resulting in the release of WG Pu to the environment. Deterministic health effects (the most serious radiobiological consequences to humans) can arise when large amounts of WG Pu are taken into the body. Inhalation is considered the most likely route of intake during work-place accidents or during a nuclear terrorism incident releasing WG Pu to the environment. Our current knowledge about radiation-related harm is insufficient for generating precise estimates of risk for a given WG Pu exposure scenario. This relates largely to uncertainties associated with currently available risk and dosimetry models. Thus, rather than generating point estimates of risk, distributions that account for variability/uncertainty are needed to properly characterize potential harm to humans from a given WG Pu exposure scenario. In this manuscript, we generate and summarize risk distributions for deterministic radiation effects in the lungs of nuclear workers from inhaled WG Pu particles (standard isotopic mix). These distributions were developed using NUREG/CR-4214 risk models and time-dependent, dose conversion factor data based on Publication 30 of the International Commission on Radiological Protection. Dose conversion factors based on ICRP Publication 30 are more relevant to deterministic effects than are the dose conversion factors based on ICRP Publication 66, which relate to targets for stochastic effects. Risk distributions that account for NUREG/CR-4214 parameter and model uncertainties were generated using the Monte Carlo method. Risks were evaluated for both lethality (from radiation pneumonitis) and morbidity (due to radiation-induced respiratory dysfunction) and were found to depend strongly on absorbed

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

    SciTech Connect

    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.

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

    PubMed Central

    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. PMID:26351652

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

    PubMed

    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. PMID:26351652

  16. Application of (13)C ramp CPMAS NMR with phase-adjusted spinning sidebands (PASS) for the quantitative estimation of carbon functional groups in natural organic matter.

    PubMed

    Ikeya, Kosuke; Watanabe, Akira

    2016-01-01

    The composition of carbon (C) functional groups in natural organic matter (NOM), such as dissolved organic matter, soil organic matter, and humic substances, is frequently estimated using solid-state (13)C NMR techniques. A problem associated with quantitative analysis using general cross polarization/magic angle spinning (CPMAS) spectra is the appearance of spinning side bands (SSBs) split from the original center peaks of sp (2) hybridized C species (i.e., aromatic and carbonyl C). Ramp CP/phase-adjusted side band suppressing (PASS) is a pulse sequence that integrates SSBs separately and quantitatively recovers them into their inherent center peaks. In the present study, the applicability of ramp CP/PASS to NOM analysis was compared with direct polarization (DPMAS), another quantitative method but one that requires a long operation time, and/or a ramp CP/total suppression side band (ramp CP/TOSS) technique, a popular but non-quantitative method for deleting SSBs. The test materials were six soil humic acid samples with various known degrees of aromaticity and two fulvic acids. There were no significant differences in the relative abundance of alkyl C, O-alkyl C, and aromatic C between the ramp CP/PASS and DPMAS methods, while the signal intensities corresponding to aromatic C in the ramp CP/TOSS spectra were consistently less than the values obtained in the ramp CP/PASS spectra. These results indicate that ramp CP/PASS can be used to accurately estimate the C composition of NOM samples. PMID:26522329

  17. The Ecology of Early Childhood Risk: A Canonical Correlation Analysis of Children’s Adjustment, Family, and Community Context in a High-Risk Sample

    PubMed Central

    Aiyer, Sophie M.; Wilson, Melvin N.; Shaw, Daniel S.; Dishion, Thomas J.

    2013-01-01

    The ecology of the emergence of psycho-pathology in early childhood is often approached by the analysis of a limited number of contextual risk factors. In the present study, we provide a comprehensive analysis of ecological risk by conducting a canonical correlation analysis of 13 risk factors at child age 2 and seven narrow-band scales of internalizing and externalizing problem behaviors at child age 4, using a sample of 364 geographically and ethnically diverse, disadvantaged primary caregivers, alternative caregivers, and preschool-age children. Participants were recruited from Special Supplemental Nutrition Program for Women, Infants, and Children sites and were screened for family risk. Canonical correlation analysis revealed that (1) a first latent combination of family and individual risks of caregivers predicted combinations of child emotional and behavioral problems, and that (2) a second latent combination of contextual and structural risks predicted child somatic complaints. Specifically, (1) the combination of chaotic home, conflict with child, parental depression, and parenting hassles predicted a co-occurrence of internalizing and externalizing behaviors, and (2) the combination of father absence, perceived discrimination, neighborhood danger, and fewer children living in the home predicted child somatic complaints. The research findings are discussed in terms of the development of psychopathology, as well as the potential prevention needs of families in high-risk contexts. PMID:23700232

  18. Comparison of Pooled Risk Estimates for Adverse Effects from Different Observational Study Designs: Methodological Overview

    PubMed Central

    Golder, Su; Loke, Yoon K.; Bland, Martin

    2013-01-01

    Background A diverse range of study designs (e.g. case-control or cohort) are used in the evaluation of adverse effects. We aimed to ascertain whether the risk estimates from meta-analyses of case-control studies differ from that of other study designs. Methods Searches were carried out in 10 databases in addition to reference checking, contacting experts, and handsearching key journals and conference proceedings. Studies were included where a pooled relative measure of an adverse effect (odds ratio or risk ratio) from case-control studies could be directly compared with the pooled estimate for the same adverse effect arising from other types of observational studies. Results We included 82 meta-analyses. Pooled estimates of harm from the different study designs had 95% confidence intervals that overlapped in 78/82 instances (95%). Of the 23 cases of discrepant findings (significant harm identified in meta-analysis of one type of study design, but not with the other study design), 16 (70%) stemmed from significantly elevated pooled estimates from case-control studies. There was associated evidence of funnel plot asymmetry consistent with higher risk estimates from case-control studies. On average, cohort or cross-sectional studies yielded pooled odds ratios 0.94 (95% CI 0.88–1.00) times lower than that from case-control studies. Interpretation Empirical evidence from this overview indicates that meta-analysis of case-control studies tend to give slightly higher estimates of harm as compared to meta-analyses of other observational studies. However it is impossible to rule out potential confounding from differences in drug dose, duration and populations when comparing between study designs. PMID:23977151

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

    SciTech Connect

    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.

  20. 49 CFR Appendix G to Part 222 - Excess Risk Estimates for Public Highway-Rail Grade Crossings

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Excess Risk Estimates for Public Highway-Rail Grade Crossings G Appendix G to Part 222 Transportation Other Regulations Relating to Transportation... HIGHWAY-RAIL GRADE CROSSINGS Pt. 222, App. G Appendix G to Part 222—Excess Risk Estimates for...

  1. COMMUNITY-RANDOMIZED INTERVENTION TRIAL WITH UV DISINFECTION FOR ESTIMATING THE RISK OF PEDIATRIC ILLNESS FROM MUNICIPAL GROUNDWATER CONSUMPTION

    EPA Science Inventory

    The goal of this study is to estimate the risk of childhood febrile and gastrointestinal illnesses associated with drinking municipal water from a groundwater source. The risk estimate will be partitioned into two separate components— illness attributable to contaminated...

  2. 49 CFR Appendix G to Part 222 - Excess Risk Estimates for Public Highway-Rail Grade Crossings

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Excess Risk Estimates for Public Highway-Rail Grade Crossings G Appendix G to Part 222 Transportation Other Regulations Relating to Transportation... HIGHWAY-RAIL GRADE CROSSINGS Pt. 222, App. G Appendix G to Part 222—Excess Risk Estimates for...

  3. 49 CFR Appendix G to Part 222 - Excess Risk Estimates for Public Highway-Rail Grade Crossings

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Excess Risk Estimates for Public Highway-Rail Grade Crossings G Appendix G to Part 222 Transportation Other Regulations Relating to Transportation... HIGHWAY-RAIL GRADE CROSSINGS Pt. 222, App. G Appendix G to Part 222—Excess Risk Estimates for...

  4. 49 CFR Appendix G to Part 222 - Excess Risk Estimates for Public Highway-Rail Grade Crossings

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Excess Risk Estimates for Public Highway-Rail Grade Crossings G Appendix G to Part 222 Transportation Other Regulations Relating to Transportation... HIGHWAY-RAIL GRADE CROSSINGS Pt. 222, App. G Appendix G to Part 222—Excess Risk Estimates for...

  5. 49 CFR Appendix G to Part 222 - Excess Risk Estimates for Public Highway-Rail Grade Crossings

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Excess Risk Estimates for Public Highway-Rail Grade Crossings G Appendix G to Part 222 Transportation Other Regulations Relating to Transportation... HIGHWAY-RAIL GRADE CROSSINGS Pt. 222, App. G Appendix G to Part 222—Excess Risk Estimates for...

  6. Adjustment disorder

    MedlinePlus

    American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Arlington, Va: American Psychiatric Publishing. 2013. Powell AD. Grief, bereavement, and adjustment disorders. In: Stern TA, Rosenbaum ...

  7. Biochemical Control With Radiotherapy Improves Overall Survival in Intermediate and High-Risk Prostate Cancer Patients Who Have an Estimated 10-Year Overall Survival of >90%

    SciTech Connect

    Herbert, Christopher; Liu, Mitchell; Tyldesley, Scott; Morris, W. James; Joffres, Michel; Khaira, Mandip; Kwan, Winkle; Moiseenko, Vitali; Pickles, Thomas

    2012-05-01

    Purpose: To identify subgroups of patients with carcinoma of the prostate treated with radical radiotherapy that have improved overall survival when disease is biochemically controlled. Methods and Materials: A cohort of 1,060 prostate cancer patients treated with radical radiotherapy was divided into nine subgroups based on National Comprehensive Cancer Network risk category and estimated 10-year overall survival (eOS 10y) derived from the age adjusted Charlson Comorbidity Index. Patients with and without biochemical control were compared with respect to overall survival. Actuarial estimates of overall survival were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of overall survival. Results: Median follow-up was 125 months (range, 51-176 months). Only the subgroups with high or intermediate risk disease and an eOS 10y of >90% had a statistically significantly improved overall survival when prostate cancer was biochemically controlled. In all other groups, biochemical control made no significant difference to overall survival. In the subgroup with high-risk disease and eOS 10y >90%, actuarial overall survival was 86.3% (95% confidence interval [CI] 78.5%-94.1%) and 62.1% (95% CI 52.9%-71.3%) for patients with biochemical control and biochemical relapse respectively (p = 0.002). In the intermediate risk group with eOS >90%, actuarial overall survival was 95.3% (95% CI 89.0%-100%) and 79.8% (95% CI 68.0%-91.6%) for biochemically controlled and biochemically relapsed patients (p = 0.033). On multivariate analysis, National Comprehensive Cancer Network risk group (p = 0.005), biochemical control (p = 0.033) and eOS 10y (p < 0.001) were statistically significant. Conclusion: Biochemical control translates into improved overall survival in patients with high or intermediate risk disease and an estimated 10-year overall survival of >90%.

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

    PubMed Central

    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. PMID:26312175

  9. Quantitative Cyber Risk Reduction Estimation Methodology for a Small Scada Control System

    SciTech Connect

    Miles A. McQueen; Wayne F. Boyer; Mark A. Flynn; George A. Beitel

    2006-01-01

    We propose a new methodology for obtaining a quick quantitative measurement of the risk reduction achieved when a control system is modified with the intent to improve cyber security defense against external attackers. The proposed methodology employs a directed graph called a compromise graph, where the nodes represent stages of a potential attack and the edges represent the expected time-to-compromise for differing attacker skill levels. Time-to-compromise is modeled as a function of known vulnerabilities and attacker skill level. The methodology was used to calculate risk reduction estimates for a specific SCADA system and for a specific set of control system security remedial actions. Despite an 86% reduction in the total number of vulnerabilities, the estimated time-to-compromise was increased only by about 3 to 30% depending on target and attacker skill level.

  10. Compensatory Postural Adjustments in an Oculus Virtual Reality Environment and the Risk of Falling in Alzheimer's Disease

    PubMed Central

    Gago, Miguel F.; Yelshyna, Darya; Bicho, Estela; Silva, Hélder David; Rocha, Luís; Lurdes Rodrigues, Maria; Sousa, Nuno

    2016-01-01

    Background/Aims Alzheimer's disease (AD) patients have an impaired ability to quickly reweight central sensory dependence in response to unexpected body perturbations. Herein, we aim to study provoked compensatory postural adjustments (CPAs) in a conflicting sensory paradigm with unpredictable visual displacements using virtual reality goggles. Methods We used kinematic time-frequency analyses of two frequency bands: a low-frequency band (LB; 0.3-1.5 Hz; mechanical strategy) and a high-frequency band (HB; 1.5-3.5 Hz; cognitive strategy). We enrolled 19 healthy subjects (controls) and 21 AD patients, divided according to their previous history of falls. Results The AD faller group presented higher-power LB CPAs, reflecting their worse inherent postural stability. The AD patients had a time lag in their HB CPA reaction. Conclusion The slower reaction by CPA in AD may be a reflection of different cognitive resources including body schema self-perception, visual motion, depth perception, or a different state of fear and/or anxiety. PMID:27489559

  11. Estimating risks of importation and local transmission of Zika virus infection

    PubMed Central

    Nah, Kyeongah; Mizumoto, Kenji; Miyamatsu, Yuichiro; Yasuda, Yohei; Kinoshita, Ryo

    2016-01-01

    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. PMID:27069825

  12. Estimating risks of importation and local transmission of Zika virus infection.

    PubMed

    Nah, Kyeongah; Mizumoto, Kenji; Miyamatsu, Yuichiro; Yasuda, Yohei; Kinoshita, Ryo; Nishiura, Hiroshi

    2016-01-01

    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. PMID:27069825

  13. Problem gambling patterns among Australian young adults: Associations with prospective risk and protective factors and adult adjustment.

    PubMed

    Scholes-Balog, Kirsty E; Hemphill, Sheryl A; Toumbourou, John W; Dowling, Nicki A

    2016-04-01

    There is instability in the developmental course of problem gambling [PG] over time; however, studies that examine PG at an aggregate level obscure these variations. The current study employed data from a longitudinal study of Australian young adults to investigate: 1) PG patterns (i.e., resistance, persistence, desistence, and new incidence); 2) prospective risk and protective factors for these patterns; and 3) behavioural outcomes associated with these patterns. A sample of 2261 young adults (55.73% female) from Victoria, Australia, who were part of the International Youth Development Study completed a survey in 2010 (T1, age 21) and 2012 (T2, age 23) measuring PG (two items based on established measures), risk and protective factors, and behavioural outcomes. The majority of the sample (91.69%) were resistors (no PG at T1 and T2), 3.62% were new incidence PG cases, 2.63% were desistors (PG at T1 but not T2), and 2.07% reported persistent PG at T1 and T2. Individual civic activism was protective of new incidence PG, while affiliation with antisocial peers and frequent alcohol use increased the risk of persistence. Persistent problem gamblers also experienced the greatest number of poor behavioural outcomes at T2. New incidence was associated with internalising symptoms at T2, while desistance was not associated with any behavioural outcomes. In conclusion, each PG pattern was associated with different predictors and outcomes, highlighting the need to consider variation in the course of young adult PG in order to provide efficacious prevention and intervention approaches, and to protect against relapse. PMID:26790138

  14. Glomerular filtration rate estimated by creatinine, cystatin C, or both markers and the risk of clinical events in HIV-infected individuals

    PubMed Central

    Lucas, Gregory M.; Cozzi-Lepri, Alessandro; Wyatt, Christina M.; Post, Frank A.; Bormann, Alison M.; Crum-Cianflone, Nancy F.; Ross, Michael J.

    2013-01-01

    Background The accuracy and precision of glomerular filtration rate (GFR) estimating equations based on plasma creatinine (GFRcr), cystatin C (GFRcys), and the combination of these markers (GFRcr-cys) has recently been assessed in HIV-infected individuals. Methods We compared the associations of baseline GFRcr, GFRcys, and GFRcr-cys (using the CKD-EPI equations) with mortality, cardiovascular events (CVE), and opportunistic diseases (OD) in the Strategies for the Management of Antiretroviral Therapy (SMART) study. We used Cox proportional hazards models to estimate unadjusted and adjusted hazard ratios per standard deviation (SD) change in GFR. Results 4,614 subjects from the SMART trial with available baseline creatinine and cystatin C data were included in this analysis. Of these, 99 died, 111 had a CVE and 121 had an OD. GFRcys was weakly to moderately correlated with HIV RNA, CD4 cell count, high sensitivity C-reactive protein, interleukin-6, and D-dimer, while GFRcr had little or no correlation with these factors. GFRcys had the strongest associations with the three clinical outcomes, followed closely by GFRcr-cys, with GFRcr having the weakest associations with clinical outcomes. In a model adjusting for demographics, cardiovascular risk factors, HIV-related factors, and inflammation markers, a 1-SD lower GFRcys was associated with a 55% (95% confidence interval [CI], 27% -90%) increased risk of mortality, a 21% (95% CI, 0% -47%) increased risk of CVE, and a 22% (95% CI, 0% -48%) increased risk of OD. Conclusions Of the three CKD-EPI GFR equations, GFRcys had the strongest associations with mortality, CVE, and OD. PMID:24024499

  15. Cancer risk estimates from radiation therapy for heterotopic ossification prophylaxis after total hip arthroplasty

    SciTech Connect

    Mazonakis, Michalis; Berris, Theoharris; Damilakis, John; Lyraraki, Efrossyni

    2013-10-15

    Purpose: Heterotopic ossification (HO) is a frequent complication following total hip arthroplasty. This study was conducted to calculate the radiation dose to organs-at-risk and estimate the probability of cancer induction from radiotherapy for HO prophylaxis.Methods: Hip irradiation for HO with a 6 MV photon beam was simulated with the aid of a Monte Carlo model. A realistic humanoid phantom representing an average adult patient was implemented in Monte Carlo environment for dosimetric calculations. The average out-of-field radiation dose to stomach, liver, lung, prostate, bladder, thyroid, breast, uterus, and ovary was calculated. The organ-equivalent-dose to colon, that was partly included within the treatment field, was also determined. Organ dose calculations were carried out using three different field sizes. The dependence of organ doses upon the block insertion into primary beam for shielding colon and prosthesis was investigated. The lifetime attributable risk for cancer development was estimated using organ, age, and gender-specific risk coefficients.Results: For a typical target dose of 7 Gy, organ doses varied from 1.0 to 741.1 mGy by the field dimensions and organ location relative to the field edge. Blocked field irradiations resulted in a dose range of 1.4–146.3 mGy. The most probable detriment from open field treatment of male patients was colon cancer with a high risk of 564.3 × 10{sup −5} to 837.4 × 10{sup −5} depending upon the organ dose magnitude and the patient's age. The corresponding colon cancer risk for female patients was (372.2–541.0) × 10{sup −5}. The probability of bladder cancer development was more than 113.7 × 10{sup −5} and 110.3 × 10{sup −5} for males and females, respectively. The cancer risk range to other individual organs was reduced to (0.003–68.5) × 10{sup −5}.Conclusions: The risk for cancer induction from radiation therapy for HO prophylaxis after total hip arthroplasty varies considerably by the

  16. Estimating the risk of squamous cell cancer induction in skin following nonlinear optical imaging.

    PubMed

    Thomas, Giju; Nadiarnykh, Oleg; van Voskuilen, Johan; Hoy, Christopher L; Gerritsen, Hans C; Sterenborg, Henricus J C M

    2014-07-01

    High power femto-second (fs) laser pulses used for in-vivo nonlinear optical (NLO) imaging can form cyclobutane pyrimidine dimers (CPD) in DNA, which may lead to carcinogenesis via subsequent mutations. Since UV radiation from routine sun exposure is the primary source of CPD lesions, we evaluated the risk of CPD-related squamous cell carcinoma (SCC) in human skin due to NLO imaging relative to that from sun exposure. We developed a unique cancer risk model expanding previously published estimation of risk from exposure to continuous wave (CW) laser. This new model showed that the increase in CPD-related SCC in skin from NLO imaging is negligible above that due to regular sun exposure. PMID:23401419

  17. The economic value of reducing environmental health risks: Contingent valuation estimates of the value of information

    SciTech Connect

    Krieger, D.J.; Hoehn, J.P.

    1999-05-01

    Obtaining economically consistent values for changes in low probability health risks continues to be a challenge for contingent valuation (CV) as well as for other valuation methods. One of the cited condition for economic consistency is that estimated values be sensitive to the scope (differences in quantity or quality) of a good described in a CV application. The alleged limitations of CV pose a particular problem for environmental managers who must often make decisions that affect human health risks. This paper demonstrates that a well-designed CV application can elicit scope sensitive values even for programs that provide conceptually complex goods such as risk reduction. Specifically, it finds that the amount sport anglers are willing to pay for information about chemical residues in fish varies systematically with informativeness--a relationship suggested by the theory of information value.

  18. Correcting for bias in relative risk estimates due to exposure measurement error: a case study of occupational exposure to antineoplastics in pharmacists.

    PubMed Central

    Spiegelman, D; Valanis, B

    1998-01-01

    OBJECTIVES: This paper describes 2 statistical methods designed to correct for bias from exposure measurement error in point and interval estimates of relative risk. METHODS: The first method takes the usual point and interval estimates of the log relative risk obtained from logistic regression and corrects them for nondifferential measurement error using an exposure measurement error model estimated from validation data. The second, likelihood-based method fits an arbitrary measurement error model suitable for the data at hand and then derives the model for the outcome of interest. RESULTS: Data from Valanis and colleagues' study of the health effects of antineoplastics exposure among hospital pharmacists were used to estimate the prevalence ratio of fever in the previous 3 months from this exposure. For an interdecile increase in weekly number of drugs mixed, the prevalence ratio, adjusted for confounding, changed from 1.06 to 1.17 (95% confidence interval [CI] = 1.04, 1.26) after correction for exposure measurement error. CONCLUSIONS: Exposure measurement error is often an important source of bias in public health research. Methods are available to correct such biases. PMID:9518972

  19. Estimating dermal uptake of nonionic organic chemicals from water and soil: I. Unified fugacity-based models for risk assessments

    SciTech Connect

    McKone, T.E. ); Howd, R.A. )

    1992-12-01

    Contamination of water and soil that might eventually contact human skin makes it imperative to include the dermal uptake route in efforts to assess potential environmental health risks. Direct measurements of dermal uptake from either water or soil are only available for a small number of the thousands of chemicals likely to be found in the environment. We propose here a mass-transfer model for estimating skin permeability and dermal uptake for organic chemicals that contaminate soil and water. Statistical relationships between measured permeabilities and chemical properties reveal that permeability varies primarily with the octanol-water partition coefficient (K[sub ow]) and secondarily with the molecular weight. From these results, we derive a fugacity-based model for skin permeability that addresses the inherent permeability of the skin, the interaction of the skin with the environmental medium on skin (water or soil), and retains a relatively simple algebraic form. Model predictions are compared to measured human skin permeabilities for some 50 compounds in water and four compounds in soil. The model is adjusted to account for dermal uptake during both short-term (10-20 min) and long-term (several hour) exposures. This model is recommended for compounds with molecular weight less than or equal to 280 g.

  20. Forest fire risk estimation from time series analisys of NOAA NDVI data

    NASA Astrophysics Data System (ADS)

    Gabban, Andrea; Liberta, Giorgio; San-Miguel-Ayanz, Jesus; Barbosa, Paulo

    2004-02-01

    The values of the Normalized Difference Vegetation Index obtained from NOAA Advanced Very High Resolution Radiometer (AVHRR) have often been used for forestry application, including the assessment of fire risk. Forest fire risk estimates were based mainly on the decrease of NDVI values during the summer in areas subject to summer drought. However, the inter-annual variability of the vegetation response has never been extensively taken into account. The present work was based on the assumption that Mediterranean vegetation is adapted to summer drought and one possible estimator of the vegetation stress was the inter-annual variability of the vegetation status, as reflected by NDVI values. This article presents a novel methodology for the assessment of fire risk based on the comparison of the current NDVI values, on a given area, with the historical values along a time series of 13 years. The first part of the study is focused on the characterization of the Minimum and Maximum long term daily images. The second part is centered on the best method to compare the long term Maximum and Minimum with the current NDVI. A statistical index, Dynamic Relative Greenness, DRG, was tested on as a novel potential fire risk indicator.

  1. Injury Risk Estimation Expertise: Cognitive-Perceptual Mechanisms of ACL-IQ.

    PubMed

    Petushek, Erich J; Cokely, Edward T; Ward, Paul; Myer, Gregory D

    2015-06-01

    Instrument-based biomechanical movement analysis is an effective injury screening method but relies on expensive equipment and time-consuming analysis. Screening methods that rely on visual inspection and perceptual skill for prognosticating injury risk provide an alternative approach that can significantly reduce cost and time. However, substantial individual differences exist in skill when estimating injury risk performance via observation. The underlying perceptual-cognitive mechanisms of injury risk identification were explored to better understand the nature of this skill and provide a foundation for improving performance. Quantitative structural and process modeling of risk estimation indicated that superior performance was largely mediated by specific strategies and skills (e.g., irrelevant information reduction), and independent of domain-general cognitive abilities (e.g., mental rotation, general decision skill). These cognitive models suggest that injury prediction expertise (i.e., ACL-IQ) is a trainable skill, and provide a foundation for future research and applications in training, decision support, and ultimately clinical screening investigations. PMID:26265341

  2. Estimate of the risks of disposing nonhazardous oil field wastes into salt caverns

    SciTech Connect

    Tomasko, D.; Elcock, D.; Veil, J.

    1997-12-31

    Argonne National Laboratory (ANL) has completed an evaluation of the possibility that adverse human health effects (carcinogenic and noncarcinogenic) could result from exposure to contaminants released from nonhazardous oil field wastes (NOW) disposed in domal salt caverns. Potential human health risks associated with hazardous substances (arsenic, benzene, cadmium, and chromium) in NOW were assessed under four postclosure cavern release scenarios: inadvertent cavern intrusion, failure of the cavern seal, failure of the cavern through cracks or leaky interbeds, and a partial collapse of the cavern roof. To estimate potential human health risks for these scenarios, contaminant concentrations at the receptor were calculated using a one-dimensional solution to an advection/dispersion equation that included first order degradation. Assuming a single, generic salt cavern and generic oil-field wastes, the best-estimate excess cancer risks ranged from 1.7 {times} 10{sup {minus}12} to 1.1 {times} 10{sup {minus}8} and hazard indices (referring to noncancer health effects) ranged from 7 {times} 10{sup {minus}9} to 7 {times} 10{sup {minus}4}. Under worse-case conditions in which the probability of cavern failure is 1.0, excess cancer risks ranged from 4.9 {times} 10{sup {minus}9} to 1.7 {times} 10{sup {minus}5} and hazard indices ranged from 7.0 {times} 10{sup {minus}4} to 0.07. Even under worst-case conditions, the risks are within the US Environmental Protection Agency (EPA) target range for acceptable exposure levels. From a human health risk perspective, salt caverns can, therefore, provide an acceptable disposal method for NOW.

  3. Estimation of sport fish harvest for risk and hazard assessment of environmental contaminants

    SciTech Connect

    Poston, T.M.; Strenge, D.L.

    1989-01-01

    Consumption of contaminated fish flesh can be a significant route of human exposure to hazardous chemicals. Estimation of exposure resulting from the consumption of fish requires knowledge of fish consumption and contaminant levels in the edible portion of fish. Realistic figures of sport fish harvest are needed to estimate consumption. Estimates of freshwater sport fish harvest were developed from a review of 72 articles and reports. Descriptive statistics based on fishing pressure were derived from harvest data for four distinct groups of freshwater sport fish in three water types: streams, lakes, and reservoirs. Regression equations were developed to relate harvest to surface area fished where data bases were sufficiently large. Other aspects of estimating human exposure to contaminants in fish flesh that are discussed include use of bioaccumulation factors for trace metals and organic compounds. Using the bioaccumulation factor and the concentration of contaminants in water as variables in the exposure equation may also lead to less precise estimates of tissue concentration. For instance, muscle levels of contaminants may not increase proportionately with increases in water concentrations, leading to overestimation of risk. In addition, estimates of water concentration may be variable or expressed in a manner that does not truly represent biological availability of the contaminant. These factors are discussed. 45 refs., 1 fig., 7 tabs.

  4. Risk estimation for future glacier lake outburst floods based on local land-use changes

    NASA Astrophysics Data System (ADS)

    Nussbaumer, S.; Schaub, Y.; Huggel, C.; Walz, A.

    2014-06-01

    Effects of climate change are particularly strong in high-mountain regions. Most visibly, glaciers are shrinking at a rapid pace, and as a consequence, glacier lakes are forming or growing. At the same time the stability of mountain slopes is reduced by glacier retreat, permafrost thaw and other factors, resulting in an increasing landslide hazard which can potentially impact lakes and therewith trigger far-reaching and devastating outburst floods. To manage risks from existing or future lakes, strategies need to be developed to plan in time for adequate risk reduction measures at a local level. However, methods to assess risks from future lake outbursts are not available and need to be developed to evaluate both future hazard and future damage potential. Here a method is presented to estimate future risks related to glacier lake outbursts for a local site in southern Switzerland (Naters, Valais). To generate two hazard scenarios, glacier shrinkage and lake formation modelling was applied, combined with simple flood modelling and field work. Furthermore, a land-use model was developed to quantify and allocate land-use changes based on local-to-regional storylines and three scenarios of land-use driving forces. Results are conceptualized in a matrix of three land-use and two hazard scenarios for the year 2045, and show the distribution of risk in the community of Naters, including high and very high risk areas. The study underlines the importance of combined risk management strategies focusing on land-use planning, on vulnerability reduction, as well as on structural measures (where necessary) to effectively reduce future risks related to lake outburst floods.

  5. Local land-use change based risk estimation for future glacier lake outburst flood

    NASA Astrophysics Data System (ADS)

    Nussbaumer, S.; Huggel, C.; Schaub, Y.; Walz, A.

    2013-08-01

    Effects of climate change are particularly strong in high-mountain regions. Most visibly, glaciers are shrinking at a rapid pace, and as a consequence, glacier lakes are forming or growing. At the same time the stability of mountain slopes is reduced by glacier retreat, permafrost thaw and other factors, resulting in an increasing risk of landslides which can potentially impact lakes and therewith trigger far reaching and devastating outburst floods. To manage risks from existing or future lakes, strategies need to be developed to plan in time for adequate risk reduction measures at a local level. However, methods to assess risks from future lake outbursts are not available. It is actually a challenge to develop methods to evaluate both, future hazard potential and future damage potential. Here we present an analysis of future risks related to glacier lake outbursts for a local site in southern Switzerland (Naters, Valais). To estimate two hazard scenarios, we used glacier shrinkage and lake formation modelling, simple flood modelling and field work. Further we developed a land-use model to quantify and allocate land-use changes based on local-to-regional storylines and three scenarios of land-use driving forces. Results are conceptualized in a matrix of three land-use and two hazard scenarios for a time period of 2045, and show the distribution of risk in the community of Naters, including high and very high risk areas. The study corroborates the importance of land-use planning to effectively reduce future risks related to lake outburst floods.

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

    SciTech Connect

    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.

  7. Marginal and Conditional Distribution Estimation from Double-Sampled Semi-Competing Risks Data

    PubMed Central

    Yu, Menggang; Yiannoutsos, Constantin T

    2015-01-01

    Informative dropout is a vexing problem for any biomedical study. Most existing statistical methods attempt to correct estimation bias related to this phenomenon by specifying unverifiable assumptions about the dropout mechanism. We consider a cohort study in Africa that uses an outreach program to ascertain the vital status for dropout subjects. These data can be used to identify a number of relevant distributions. However, as only a subset of dropout subjects were followed, vital status ascertainment was incomplete. We use semi-competing risk methods as our analysis framework to address this specific case where the terminal event is incompletely ascertained and consider various procedures for estimating the marginal distribution of dropout and the marginal and conditional distributions of survival. We also consider model selection and estimation efficiency in our setting. Performance of the proposed methods is demonstrated via simulations, asymptotic study, and analysis of the study data. PMID:26924877

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

    NASA Technical Reports Server (NTRS)

    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).

  9. Radiation-Induced Leukemia at Doses Relevant to Radiation Therapy: Modeling Mechanisms and Estimating Risks

    NASA Technical Reports Server (NTRS)

    Shuryak, Igor; Sachs, Rainer K.; Hlatky, Lynn; Mark P. Little; Hahnfeldt, Philip; Brenner, David J.

    2006-01-01

    Because many cancer patients are diagnosed earlier and live longer than in the past, second cancers induced by radiation therapy have become a clinically significant issue. An earlier biologically based model that was designed to estimate risks of high-dose radiation induced solid cancers included initiation of stem cells to a premalignant state, inactivation of stem cells at high radiation doses, and proliferation of stem cells during cellular repopulation after inactivation. This earlier model predicted the risks of solid tumors induced by radiation therapy but overestimated the corresponding leukemia risks. Methods: To extend the model to radiation-induced leukemias, we analyzed in addition to cellular initiation, inactivation, and proliferation a repopulation mechanism specific to the hematopoietic system: long-range migration through the blood stream of hematopoietic stem cells (HSCs) from distant locations. Parameters for the model were derived from HSC biologic data in the literature and from leukemia risks among atomic bomb survivors v^ ho were subjected to much lower radiation doses. Results: Proliferating HSCs that migrate from sites distant from the high-dose region include few preleukemic HSCs, thus decreasing the high-dose leukemia risk. The extended model for leukemia provides risk estimates that are consistent with epidemiologic data for leukemia risk associated with radiation therapy over a wide dose range. For example, when applied to an earlier case-control study of 110000 women undergoing radiotherapy for uterine cancer, the model predicted an excess relative risk (ERR) of 1.9 for leukemia among women who received a large inhomogeneous fractionated external beam dose to the bone marrow (mean = 14.9 Gy), consistent with the measured ERR (2.0, 95% confidence interval [CI] = 0.2 to 6.4; from 3.6 cases expected and 11 cases observed). As a corresponding example for brachytherapy, the predicted ERR of 0.80 among women who received an inhomogeneous low

  10. Estimated compliance for removal of specified risk materials from 18 U.S. beef packing plants.

    PubMed

    Dewell, R D; Hoffman, T W; Woerner, D R; Belk, K E; Whalen, L R; Fails, A D; Scanga, J A; Smith, G C; Salman, M D

    2008-03-01

    The removal of 18,345 specified risk materials was observed during audits of 18 U.S. beef processing facilities that, in total, account for over 90% of total U.S. beef slaughtered. Audited plants varied in capacity (280 to 6,000 head per day) and processed both "fed (young cattle)" and "nonfed (mature cows/bulls)" cattle. When all observations for removal of specified risk materials were combined from plants and adjusted for type of cattle processed, overall compliance with specified risk material removal regulations was 98.08%. A 100% compliance rate for removal of brains and distal ileums was recorded based on a total of 600 observations for removal of brains and a total of 2,400 observations for removal of distal ileums. Observations for removal of dorsal root ganglia were collected from 16 of the 18 plants, and overall compliance for dorsal root ganglia removal was 99.6% (4,783 of 4,800). Fifteen of the 16 plants were 100% compliant. For tonsils, data from 18 plants were collected, and tonsils were correctly removed from 92.8% (4,777 of 5,145) of tongues and heads. Data for spinal cord removal were collected from 18 plants, and the spinal cord was removed completely in line with U.S. Department of Agriculture-Food Safety and Inspection Service regulations for 99.43% of the observations. Based on the results of this study, packing plants have demonstrated that they are complying with regulations for removal of specified risk materials from beef meat products intended for human consumption greater than 98% of the time. To continue to assure food safety and consumer confidence, continued vigilance and provision of training programs for plant workers are essential. PMID:18389702

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

    PubMed

    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 < 5 mSv), or population exposure by water-independent pathways (50-y CEDE < 80 mSv). The greatest hazard is related to the water contamination in conditions of effective leaching of uranium in the groundwater (50-y CEDE < 400 mSv). Even in this worst case scenario, the chemical toxicity largely predominates over radiological risk. These computer simulations suggest that little radiological risk is associated to the use of depleted uranium weapons. PMID:11768794

  12. Quantitative risk estimation for a Legionella pneumophila infection due to whirlpool use.

    PubMed

    Bouwknegt, Martijn; Schijven, Jack F; Schalk, Johanna A C; de Roda Husman, Ana Maria

    2013-07-01

    Quantitative microbiological risk assessment was used to quantify the risk associated with the exposure to Legionella pneumophila in a whirlpool. Conceptually, air bubbles ascend to the surface, intercepting Legionella from the traversed water. At the surface the bubble bursts into dominantly noninhalable jet drops and inhalable film drops. Assuming that film drops carry half of the intercepted Legionella, a total of four (95% interval: 1-9) and 4.5×10(4) (4.4×10(4) - 4.7×10(4) ) cfu/min were estimated to be aerosolized for concentrations of 1 and 1,000 legionellas per liter, respectively. Using a dose-response model for guinea pigs to represent humans, infection risks for active whirlpool use with 100 cfu/L water for 15 minutes were 0.29 (∼0.11-0.48) for susceptible males and 0.22 (∼0.06-0.42) for susceptible females. A L. pneumophila concentration of ≥1,000 cfu/L water was estimated to nearly always cause an infection (mean: 0.95; 95% interval: 0.9-∼1). Estimated infection risks were time-dependent, ranging from 0.02 (0-0.11) for 1-minute exposures to 0.93 (0.86-0.97) for 2-hour exposures when the L. pneumophila concentration was 100 cfu/L water. Pool water in Dutch bathing establishments should contain <100 cfu Legionella/L water. This study suggests that stricter provisions might be required to assure adequate public health protection. PMID:23078231

  13. Estimates of the auditory risk from outdoor impulse noise. I: Firecrackers.

    PubMed

    Flamme, Gregory A; Liebe, Kevin; Wong, Adam

    2009-01-01

    Firecrackers are common impulse noise exposures in the United States. In this study, impulses produced outdoors by consumer firecrackers were recorded, described, and analyzed with respect to the amount of the auditory risk they pose to the unprotected listener under various listening conditions. Risk estimates were obtained using three contemporary damage risk criteria (DRC), including a waveform parameter-based approach (peak SPL and B duration), an energy-based criterion (A-weighted sound exposure level and equivalent continuous level), and a physiological model (the AHAAH model developed by Price and Kalb). Results from these DRC were converted into numbers of maximum permissible unprotected exposures to facilitate comparison. Acoustic characteristics of firecracker impulses varied with the distance, but only subtle differences were observed across firecrackers. Typical peak levels ranged between 171 dB SPL at 0.5 m and 142 dB SPL at 8 m. Estimates of the auditory risk did not differ significantly across firecrackers, but varied with the distance. Vast differences in maximum permissible exposures were observed, and the directions of the differences varied with the level of the impulse. Typical estimates of maximum permissible exposures ranged between 0 and 2 at 0.5 m and between 31 and 227,000 at 8 m. Unprotected exposures to firecracker impulses should be limited or avoided entirely if the firecrackers are ignited in batches within 8 m of the listener. Differences across DRC are inconsequential at 0.5 m, but have substantial implications at distances of 1 m and more. PMID:19805932

  14. A dimensional approach to understanding severity estimates and risk correlates of marijuana abuse and dependence in adults

    PubMed Central

    WU, LI-TZY; WOODY, GEORGE E.; YANG, CHONGMING; PAN, JENG-JONG; REEVE, BRYCE B.; BLAZER, DAN G.

    2012-01-01

    While item response theory (IRT) research shows a latent severity trait underlying response patterns of substance abuse and dependence symptoms, little is known about IRT-based severity estimates in relation to clinically relevant measures. In response to increased prevalences of marijuana-related treatment admissions, an elevated level of marijuana potency, and the debate on medical marijuana use, we applied dimensional approaches to understand IRT-based severity estimates for marijuana use disorders (MUDs) and their correlates while simultaneously considering gender- and race/ethnicity-related differential item functioning (DIF). Using adult data from the 2008 National Survey on Drug Use and Health (N=37,897), DSM-IV criteria for MUDs among past-year marijuana users were examined by IRT, logistic regression, and multiple indicators–multiple causes (MIMIC) approaches. Among 6,917 marijuana users, 15% met criteria for a MUD; another 24% exhibited subthreshold dependence. Abuse criteria were highly correlated with dependence criteria (correlation=0.90), indicating unidimensionality; item information curves revealed redundancy in multiple criteria. MIMIC analyses showed that MUD criteria were positively associated with weekly marijuana use, early marijuana use, other substance use disorders, substance abuse treatment, and serious psychological distress. African Americans and Hispanics showed higher levels of MUDs than whites, even after adjusting for race/ethnicity-related DIF. The redundancy in multiple criteria suggests an opportunity to improve efficiency in measuring symptom-level manifestations by removing low-informative criteria. Elevated rates of MUDs among African Americans and Hispanics require research to elucidate risk factors and improve assessments of MUDs for different racial/ethnic groups. PMID:22351489

  15. Estimating health risk from exposure to 1,4-dioxane in Japan.

    PubMed

    Makino, Ryoji; Kawasaki, Hajime; Kishimoto, Atsuo; Gamo, Masashi; Nakanishi, Junko

    2006-01-01

    Exposure to 1,4-dioxane from the atmosphere around high-emission plants and from consumer products used in daily life that contain the substance may have adverse health effects; however, its emission into the atmosphere is not regulated. In this study, the health risk posed by 1,4-dioxane is assessed to investigate whether measures should be undertaken to reduce exposure to 1,4-dioxane. The notion of the margin of exposure (MOE), given by the ratio of no observed adverse effect level (NOAEL) to actual or projected exposure level, is used to assess risk. In exposure assessment, two types of exposure channel are considered: (a) the use of consumer products that contain 1,4-dioxane and (b) the inhalation of air around high-emission plants. To estimate exposure via channel (a), we measured the concentration of 1,4-dioxane in consumer products and estimated the interindividual variability of exposure by Monte Carlo simulation that reflects the measured data. To estimate exposure via channel (b), we employed a local-level atmospheric dispersion model to estimate the concentration of 1,4-dioxane immediately around high-emission plants. For hazard assessment, we derived the inhalatory and oral NOAELs for liver adenomas and carcinomas and the uncertainty factor. The results suggest that measures are not needed to reduce exposure to 1,4-dioxane from consumer products. As for inhalation exposure around high-emission plants, some residents may be exposed to health risks if certain conservative analytical conditions are assumed. Even in this case, we conclude that it is not necessary for Plant A to stop the use of 1,4-dioxane immediately and that medium- to long-term emission reduction measures should be sufficient. PMID:16685251

  16. Estimating Loss-of-Coolant Accident Frequencies for the Standardized Plant Analysis Risk Models

    SciTech Connect

    S. A. Eide; D. M. Rasmuson; C. L. Atwood

    2008-09-01

    The U.S. Nuclear Regulatory Commission maintains a set of risk models covering the U.S. commercial nuclear power plants. These standardized plant analysis risk (SPAR) models include several loss-of-coolant accident (LOCA) initiating events such as small (SLOCA), medium (MLOCA), and large (LLOCA). All of these events involve a loss of coolant inventory from the reactor coolant system. In order to maintain a level of consistency across these models, initiating event frequencies generally are based on plant-type average performance, where the plant types are boiling water reactors and pressurized water reactors. For certain risk analyses, these plant-type initiating event frequencies may be replaced by plant-specific estimates. Frequencies for SPAR LOCA initiating events previously were based on results presented in NUREG/CR-5750, but the newest models use results documented in NUREG/CR-6928. The estimates in NUREG/CR-6928 are based on historical data from the initiating events database for pressurized water reactor SLOCA or an interpretation of results presented in the draft version of NUREG-1829. The information in NUREG-1829 can be used several ways, resulting in different estimates for the various LOCA frequencies. Various ways NUREG-1829 information can be used to estimate LOCA frequencies were investigated and this paper presents two methods for the SPAR model standard inputs, which differ from the method used in NUREG/CR-6928. In addition, results obtained from NUREG-1829 are compared with actual operating experience as contained in the initiating events database.

  17. Direct estimates of low-level radiation risks of lung cancer at two NRC-compliant nuclear installations: why are the new risk estimates 20 to 200 times the old official estimates?

    PubMed Central

    Bross, I. D.; Driscoll, D. L.

    1981-01-01

    An official report on the health hazards to nuclear submarine workers at the Portsmouth Naval Shipyard (PNS), who were exposed to low-level ionizing radiation, was based on a casual inspection of the data and not on statistical analyses of the dosage-response relationships. When these analyses are done, serious hazards from lung cancer and other causes of death are shown. As a result of the recent studies on nuclear workers, the new risk estimates have been found to be much higher than the official estimates currently used in setting NRC permissible levels. The official BEIR estimates are about one lung cancer death per year per million persons per rem[s]. The PNS data show 189 lung cancer deaths per year per million persons per rem. PMID:7336762

  18. 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

    PubMed Central

    2010-01-01

    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 statin drug therapy

  19. Impact of ground motion characterization on conservatism and variability in seismic risk estimates

    SciTech Connect

    Sewell, R.T.; Toro, G.R.; McGuire, R.K.

    1996-07-01

    This study evaluates the impact, on estimates of seismic risk and its uncertainty, of alternative methods in treatment and characterization of earthquake ground motions. The objective of this study is to delineate specific procedures and characterizations that may lead to less biased and more precise seismic risk results. This report focuses on sources of conservatism and variability in risk that may be introduced through the analytical processes and ground-motion descriptions which are commonly implemented at the interface of seismic hazard and fragility assessments. In particular, implication of the common practice of using a single, composite spectral shape to characterize motions of different magnitudes is investigated. Also, the impact of parameterization of ground motion on fragility and hazard assessments is shown. Examination of these results demonstrates the following. (1) There exists significant conservatism in the review spectra (usually, spectra characteristic of western U.S. earthquakes) that have been used in conducting past seismic risk assessments and seismic margin assessments for eastern U.S. nuclear power plants. (2) There is a strong dependence of seismic fragility on earthquake magnitude when PGA is used as the ground-motion characterization. When, however, magnitude-dependent spectra are anchored to a common measure of elastic spectral acceleration averaged over the appropriate frequency range, seismic fragility shows no important nor consistent dependence on either magnitude or strong-motion duration. Use of inelastic spectral acceleration (at the proper frequency) as the ground spectrum anchor demonstrates a very similar result. This study concludes that a single, composite-magnitude spectrum can generally be used to characterize ground motion for fragility assessment without introducing significant bias or uncertainty in seismic risk estimates.

  20. Carbohydrate intake, obesity, metabolic syndrome and cancer risk? A two-part systematic review and meta-analysis protocol to estimate attributability

    PubMed Central

    Sartorius, B; Sartorius, K; Aldous, C; Madiba, T E; Stefan, C; Noakes, T

    2016-01-01

    Introduction Linkages between carbohydrates, obesity and cancer continue to demonstrate conflicting results. Evidence suggests inconclusive direct linkages between carbohydrates and specific cancers. Conversely, obesity has been strongly linked to a wide range of cancers. The purpose of the study is to explore linkages between carbohydrate intake and cancer types using a two-step approach. First the study will evaluate the linkages between carbohydrate intake and obesity, potentially stratified by metabolic syndrome status. Second, the estimated attributable fraction of obesity ascribed to carbohydrate intake will be multiplied against obesity attributable fractions for cancer types to give estimated overall attributable fraction for carbohydrate versus cancer type. Methods and analysis We will perform a comprehensive search to identify all possible published and unpublished studies that have assessed risk factors for obesity including dietary carbohydrate intake. Scientific databases, namely PubMed MEDLINE, EMBASE, EBSCOhost and ISI Web of Science will be searched. Following study selection, paper/data acquisition, and data extraction and synthesis, we will appraise the quality of studies and risk of bias, as well as assess heterogeneity. Meta-weighted attributable fractions of obesity due to carbohydrate intake will be estimated after adjusting for other potential confounding factors (eg, physical inactivity, other dietary intake). Furthermore, previously published systematic reviews assessing the cancer-specific risk associated with obesity will also be drawn. These estimates will be linked with the attributability of carbohydrate intake in part 1 to estimate the cancer-specific burden that can be attributed to dietary carbohydrates. This systematic review protocol has been developed according to the ‘Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) 2015’. Ethics and dissemination T