nominal coverage probability: Topics by Science.gov

Sample records for nominal coverage probability

Adjusting for Confounding in Early Postlaunch Settings: Going Beyond Logistic Regression Models.

PubMed

Schmidt, Amand F; Klungel, Olaf H; Groenwold, Rolf H H

2016-01-01

Postlaunch data on medical treatments can be analyzed to explore adverse events or relative effectiveness in real-life settings. These analyses are often complicated by the number of potential confounders and the possibility of model misspecification. We conducted a simulation study to compare the performance of logistic regression, propensity score, disease risk score, and stabilized inverse probability weighting methods to adjust for confounding. Model misspecification was induced in the independent derivation dataset. We evaluated performance using relative bias confidence interval coverage of the true effect, among other metrics. At low events per coefficient (1.0 and 0.5), the logistic regression estimates had a large relative bias (greater than -100%). Bias of the disease risk score estimates was at most 13.48% and 18.83%. For the propensity score model, this was 8.74% and >100%, respectively. At events per coefficient of 1.0 and 0.5, inverse probability weighting frequently failed or reduced to a crude regression, resulting in biases of -8.49% and 24.55%. Coverage of logistic regression estimates became less than the nominal level at events per coefficient ≤5. For the disease risk score, inverse probability weighting, and propensity score, coverage became less than nominal at events per coefficient ≤2.5, ≤1.0, and ≤1.0, respectively. Bias of misspecified disease risk score models was 16.55%. In settings with low events/exposed subjects per coefficient, disease risk score methods can be useful alternatives to logistic regression models, especially when propensity score models cannot be used. Despite better performance of disease risk score methods than logistic regression and propensity score models in small events per coefficient settings, bias, and coverage still deviated from nominal.
Confidence Intervals for True Scores Using the Skew-Normal Distribution

ERIC Educational Resources Information Center

Garcia-Perez, Miguel A.

2010-01-01

A recent comparative analysis of alternative interval estimation approaches and procedures has shown that confidence intervals (CIs) for true raw scores determined with the Score method--which uses the normal approximation to the binomial distribution--have actual coverage probabilities that are closest to their nominal level. It has also recently…
Intervals for posttest probabilities: a comparison of 5 methods.

PubMed

Mossman, D; Berger, J O

2001-01-01

Several medical articles discuss methods of constructing confidence intervals for single proportions and the likelihood ratio, but scant attention has been given to the systematic study of intervals for the posterior odds, or the positive predictive value, of a test. The authors describe 5 methods of constructing confidence intervals for posttest probabilities when estimates of sensitivity, specificity, and the pretest probability of a disorder are derived from empirical data. They then evaluate each method to determine how well the intervals' coverage properties correspond to their nominal value. When the estimates of pretest probabilities, sensitivity, and specificity are derived from more than 80 subjects and are not close to 0 or 1, all methods generate intervals with appropriate coverage properties. When these conditions are not met, however, the best-performing method is an objective Bayesian approach implemented by a simple simulation using a spreadsheet. Physicians and investigators can generate accurate confidence intervals for posttest probabilities in small-sample situations using the objective Bayesian approach.
Exact one-sided confidence limits for the difference between two correlated proportions.

PubMed

Lloyd, Chris J; Moldovan, Max V

2007-08-15

We construct exact and optimal one-sided upper and lower confidence bounds for the difference between two probabilities based on matched binary pairs using well-established optimality theory of Buehler. Starting with five different approximate lower and upper limits, we adjust them to have coverage probability exactly equal to the desired nominal level and then compare the resulting exact limits by their mean size. Exact limits based on the signed root likelihood ratio statistic are preferred and recommended for practical use.
Simultaneous confidence sets for several effective doses.

PubMed

Tompsett, Daniel M; Biedermann, Stefanie; Liu, Wei

2018-04-03

Construction of simultaneous confidence sets for several effective doses currently relies on inverting the Scheffé type simultaneous confidence band, which is known to be conservative. We develop novel methodology to make the simultaneous coverage closer to its nominal level, for both two-sided and one-sided simultaneous confidence sets. Our approach is shown to be considerably less conservative than the current method, and is illustrated with an example on modeling the effect of smoking status and serum triglyceride level on the probability of the recurrence of a myocardial infarction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
77 FR 50110 - Medicare Program; Request for Nominations for Members for the Medicare Evidence Development...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

...] Medicare Program; Request for Nominations for Members for the Medicare Evidence Development & Coverage... notice announces the request for nominations for membership on the Medicare Evidence Development... Centers for Medicare & Medicaid Services (CMS) concerning the adequacy of scientific evidence available to...
Confidence intervals for the between-study variance in random-effects meta-analysis using generalised heterogeneity statistics: should we use unequal tails?

PubMed

Jackson, Dan; Bowden, Jack

2016-09-07

Confidence intervals for the between study variance are useful in random-effects meta-analyses because they quantify the uncertainty in the corresponding point estimates. Methods for calculating these confidence intervals have been developed that are based on inverting hypothesis tests using generalised heterogeneity statistics. Whilst, under the random effects model, these new methods furnish confidence intervals with the correct coverage, the resulting intervals are usually very wide, making them uninformative. We discuss a simple strategy for obtaining 95 % confidence intervals for the between-study variance with a markedly reduced width, whilst retaining the nominal coverage probability. Specifically, we consider the possibility of using methods based on generalised heterogeneity statistics with unequal tail probabilities, where the tail probability used to compute the upper bound is greater than 2.5 %. This idea is assessed using four real examples and a variety of simulation studies. Supporting analytical results are also obtained. Our results provide evidence that using unequal tail probabilities can result in shorter 95 % confidence intervals for the between-study variance. We also show some further results for a real example that illustrates how shorter confidence intervals for the between-study variance can be useful when performing sensitivity analyses for the average effect, which is usually the parameter of primary interest. We conclude that using unequal tail probabilities when computing 95 % confidence intervals for the between-study variance, when using methods based on generalised heterogeneity statistics, can result in shorter confidence intervals. We suggest that those who find the case for using unequal tail probabilities convincing should use the '1-4 % split', where greater tail probability is allocated to the upper confidence bound. The 'width-optimal' interval that we present deserves further investigation.
75 FR 78705 - Medicare Program; Request for Nominations for Members for the Medicare Evidence Development...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-16

...] Medicare Program; Request for Nominations for Members for the Medicare Evidence Development & Coverage... notice announces the request for nominations for consideration for membership on the Medicare Evidence... serve on the MEDCAC. Nominees are selected based upon their individual qualifications and not as...
Preflight SL-1/SL-3 Skylab VHF ranging coverage (nominal TPI). Antenna and propagation studies for spacecraft systems, task E-531

NASA Technical Reports Server (NTRS)

Eisenhauer, D. R.; James, D. A.

1973-01-01

A preflight assessment of the Skylab VHF ranging coverage for the rendezvous portion of the nominal SL-1/SL-3 mission is reported, assuming a 27 July 1973 SL-3 launch. Data are based on a nominal attitude trajectory, which has the Saturn workshop in a solar inertial attitude throughout the rendezvous; the CSM terminal phase initiation maneuver is nominal. An addendum to this report is being prepared, which considers the effects of early and late TPI maneuvers. Curves are presented which show the variation in received power levels on both spacecraft-to-spacecraft links from about 600 n.mi. range to CSM and SWS station keeping. Appropriate threshold levels are shown on these received power curves to indicate zero circuit margins for the ranging function.
Meta-analysis of few small studies in orphan diseases.

PubMed

Friede, Tim; Röver, Christian; Wandel, Simon; Neuenschwander, Beat

2017-03-01

Meta-analyses in orphan diseases and small populations generally face particular problems, including small numbers of studies, small study sizes and heterogeneity of results. However, the heterogeneity is difficult to estimate if only very few studies are included. Motivated by a systematic review in immunosuppression following liver transplantation in children, we investigate the properties of a range of commonly used frequentist and Bayesian procedures in simulation studies. Furthermore, the consequences for interval estimation of the common treatment effect in random-effects meta-analysis are assessed. The Bayesian credibility intervals using weakly informative priors for the between-trial heterogeneity exhibited coverage probabilities in excess of the nominal level for a range of scenarios considered. However, they tended to be shorter than those obtained by the Knapp-Hartung method, which were also conservative. In contrast, methods based on normal quantiles exhibited coverages well below the nominal levels in many scenarios. With very few studies, the performance of the Bayesian credibility intervals is of course sensitive to the specification of the prior for the between-trial heterogeneity. In conclusion, the use of weakly informative priors as exemplified by half-normal priors (with a scale of 0.5 or 1.0) for log odds ratios is recommended for applications in rare diseases. © 2016 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd. © 2016 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd.
42 CFR 423.308 - Definitions and terminology.

Code of Federal Regulations, 2010 CFR

2010-10-01

... exclude any costs attributable to benefits beyond basic prescription drug coverage, but also to exclude... benefits beyond basic prescription drug coverage, but also to exclude any prescription drug coverage costs... assistance outside the Part D benefit, provided that documentation of such nominal cost-sharing has been...
Multiple Imputation in Two-Stage Cluster Samples Using The Weighted Finite Population Bayesian Bootstrap.

PubMed

Zhou, Hanzhi; Elliott, Michael R; Raghunathan, Trivellore E

2016-06-01

Multistage sampling is often employed in survey samples for cost and convenience. However, accounting for clustering features when generating datasets for multiple imputation is a nontrivial task, particularly when, as is often the case, cluster sampling is accompanied by unequal probabilities of selection, necessitating case weights. Thus, multiple imputation often ignores complex sample designs and assumes simple random sampling when generating imputations, even though failing to account for complex sample design features is known to yield biased estimates and confidence intervals that have incorrect nominal coverage. In this article, we extend a recently developed, weighted, finite-population Bayesian bootstrap procedure to generate synthetic populations conditional on complex sample design data that can be treated as simple random samples at the imputation stage, obviating the need to directly model design features for imputation. We develop two forms of this method: one where the probabilities of selection are known at the first and second stages of the design, and the other, more common in public use files, where only the final weight based on the product of the two probabilities is known. We show that this method has advantages in terms of bias, mean square error, and coverage properties over methods where sample designs are ignored, with little loss in efficiency, even when compared with correct fully parametric models. An application is made using the National Automotive Sampling System Crashworthiness Data System, a multistage, unequal probability sample of U.S. passenger vehicle crashes, which suffers from a substantial amount of missing data in "Delta-V," a key crash severity measure.
Multiple Imputation in Two-Stage Cluster Samples Using The Weighted Finite Population Bayesian Bootstrap

PubMed Central

Zhou, Hanzhi; Elliott, Michael R.; Raghunathan, Trivellore E.

2017-01-01

Multistage sampling is often employed in survey samples for cost and convenience. However, accounting for clustering features when generating datasets for multiple imputation is a nontrivial task, particularly when, as is often the case, cluster sampling is accompanied by unequal probabilities of selection, necessitating case weights. Thus, multiple imputation often ignores complex sample designs and assumes simple random sampling when generating imputations, even though failing to account for complex sample design features is known to yield biased estimates and confidence intervals that have incorrect nominal coverage. In this article, we extend a recently developed, weighted, finite-population Bayesian bootstrap procedure to generate synthetic populations conditional on complex sample design data that can be treated as simple random samples at the imputation stage, obviating the need to directly model design features for imputation. We develop two forms of this method: one where the probabilities of selection are known at the first and second stages of the design, and the other, more common in public use files, where only the final weight based on the product of the two probabilities is known. We show that this method has advantages in terms of bias, mean square error, and coverage properties over methods where sample designs are ignored, with little loss in efficiency, even when compared with correct fully parametric models. An application is made using the National Automotive Sampling System Crashworthiness Data System, a multistage, unequal probability sample of U.S. passenger vehicle crashes, which suffers from a substantial amount of missing data in “Delta-V,” a key crash severity measure. PMID:29226161
One- and two-stage Arrhenius models for pharmaceutical shelf life prediction.

PubMed

Fan, Zhewen; Zhang, Lanju

2015-01-01

One of the most challenging aspects of the pharmaceutical development is the demonstration and estimation of chemical stability. It is imperative that pharmaceutical products be stable for two or more years. Long-term stability studies are required to support such shelf life claim at registration. However, during drug development to facilitate formulation and dosage form selection, an accelerated stability study with stressed storage condition is preferred to quickly obtain a good prediction of shelf life under ambient storage conditions. Such a prediction typically uses Arrhenius equation that describes relationship between degradation rate and temperature (and humidity). Existing methods usually rely on the assumption of normality of the errors. In addition, shelf life projection is usually based on confidence band of a regression line. However, the coverage probability of a method is often overlooked or under-reported. In this paper, we introduce two nonparametric bootstrap procedures for shelf life estimation based on accelerated stability testing, and compare them with a one-stage nonlinear Arrhenius prediction model. Our simulation results demonstrate that one-stage nonlinear Arrhenius method has significant lower coverage than nominal levels. Our bootstrap method gave better coverage and led to a shelf life prediction closer to that based on long-term stability data.
Multi-Reader ROC studies with Split-Plot Designs: A Comparison of Statistical Methods

PubMed Central

Obuchowski, Nancy A.; Gallas, Brandon D.; Hillis, Stephen L.

2012-01-01

Rationale and Objectives Multi-reader imaging trials often use a factorial design, where study patients undergo testing with all imaging modalities and readers interpret the results of all tests for all patients. A drawback of the design is the large number of interpretations required of each reader. Split-plot designs have been proposed as an alternative, in which one or a subset of readers interprets all images of a sample of patients, while other readers interpret the images of other samples of patients. In this paper we compare three methods of analysis for the split-plot design. Materials and Methods Three statistical methods are presented: Obuchowski-Rockette method modified for the split-plot design, a newly proposed marginal-mean ANOVA approach, and an extension of the three-sample U-statistic method. A simulation study using the Roe-Metz model was performed to compare the type I error rate, power and confidence interval coverage of the three test statistics. Results The type I error rates for all three methods are close to the nominal level but tend to be slightly conservative. The statistical power is nearly identical for the three methods. The coverage of 95% CIs fall close to the nominal coverage for small and large sample sizes. Conclusions The split-plot MRMC study design can be statistically efficient compared with the factorial design, reducing the number of interpretations required per reader. Three methods of analysis, shown to have nominal type I error rate, similar power, and nominal CI coverage, are available for this study design. PMID:23122570
Multi-reader ROC studies with split-plot designs: a comparison of statistical methods.

PubMed

Obuchowski, Nancy A; Gallas, Brandon D; Hillis, Stephen L

2012-12-01

Multireader imaging trials often use a factorial design, in which study patients undergo testing with all imaging modalities and readers interpret the results of all tests for all patients. A drawback of this design is the large number of interpretations required of each reader. Split-plot designs have been proposed as an alternative, in which one or a subset of readers interprets all images of a sample of patients, while other readers interpret the images of other samples of patients. In this paper, the authors compare three methods of analysis for the split-plot design. Three statistical methods are presented: the Obuchowski-Rockette method modified for the split-plot design, a newly proposed marginal-mean analysis-of-variance approach, and an extension of the three-sample U-statistic method. A simulation study using the Roe-Metz model was performed to compare the type I error rate, power, and confidence interval coverage of the three test statistics. The type I error rates for all three methods are close to the nominal level but tend to be slightly conservative. The statistical power is nearly identical for the three methods. The coverage of 95% confidence intervals falls close to the nominal coverage for small and large sample sizes. The split-plot multireader, multicase study design can be statistically efficient compared to the factorial design, reducing the number of interpretations required per reader. Three methods of analysis, shown to have nominal type I error rates, similar power, and nominal confidence interval coverage, are available for this study design. Copyright © 2012 AUR. All rights reserved.
Estimating stage-specific daily survival probabilities of nests when nest age is unknown

USGS Publications Warehouse

Stanley, T.R.

2004-01-01

Estimation of daily survival probabilities of nests is common in studies of avian populations. Since the introduction of Mayfield's (1961, 1975) estimator, numerous models have been developed to relax Mayfield's assumptions and account for biologically important sources of variation. Stanley (2000) presented a model for estimating stage-specific (e.g. incubation stage, nestling stage) daily survival probabilities of nests that conditions on “nest type” and requires that nests be aged when they are found. Because aging nests typically requires handling the eggs, there may be situations where nests can not or should not be aged and the Stanley (2000) model will be inapplicable. Here, I present a model for estimating stage-specific daily survival probabilities that conditions on nest stage for active nests, thereby obviating the need to age nests when they are found. Specifically, I derive the maximum likelihood function for the model, evaluate the model's performance using Monte Carlo simulations, and provide software for estimating parameters (along with an example). For sample sizes as low as 50 nests, bias was small and confidence interval coverage was close to the nominal rate, especially when a reduced-parameter model was used for estimation.
Advances in the meta-analysis of heterogeneous clinical trials II: The quality effects model.

PubMed

Doi, Suhail A R; Barendregt, Jan J; Khan, Shahjahan; Thalib, Lukman; Williams, Gail M

2015-11-01

This article examines the performance of the updated quality effects (QE) estimator for meta-analysis of heterogeneous studies. It is shown that this approach leads to a decreased mean squared error (MSE) of the estimator while maintaining the nominal level of coverage probability of the confidence interval. Extensive simulation studies confirm that this approach leads to the maintenance of the correct coverage probability of the confidence interval, regardless of the level of heterogeneity, as well as a lower observed variance compared to the random effects (RE) model. The QE model is robust to subjectivity in quality assessment down to completely random entry, in which case its MSE equals that of the RE estimator. When the proposed QE method is applied to a meta-analysis of magnesium for myocardial infarction data, the pooled mortality odds ratio (OR) becomes 0.81 (95% CI 0.61-1.08) which favors the larger studies but also reflects the increased uncertainty around the pooled estimate. In comparison, under the RE model, the pooled mortality OR is 0.71 (95% CI 0.57-0.89) which is less conservative than that of the QE results. The new estimation method has been implemented into the free meta-analysis software MetaXL which allows comparison of alternative estimators and can be downloaded from www.epigear.com. Copyright © 2015 Elsevier Inc. All rights reserved.
Impact of coverage on the reliability of a fault tolerant computer

NASA Technical Reports Server (NTRS)

Bavuso, S. J.

1975-01-01

A mathematical reliability model is established for a reconfigurable fault tolerant avionic computer system utilizing state-of-the-art computers. System reliability is studied in light of the coverage probabilities associated with the first and second independent hardware failures. Coverage models are presented as a function of detection, isolation, and recovery probabilities. Upper and lower bonds are established for the coverage probabilities and the method for computing values for the coverage probabilities is investigated. Further, an architectural variation is proposed which is shown to enhance coverage.
Modeling Training Site Vegetation Coverage Probability with a Random Optimizing Procedure: An Artificial Neural Network Approach.

DTIC Science & Technology

1998-05-01

Coverage Probability with a Random Optimization Procedure: An Artificial Neural Network Approach by Biing T. Guan, George Z. Gertner, and Alan B...Modeling Training Site Vegetation Coverage Probability with a Random Optimizing Procedure: An Artificial Neural Network Approach 6. AUTHOR(S) Biing...coverage based on past coverage. Approach A literature survey was conducted to identify artificial neural network analysis techniques applicable for

MO-FG-CAMPUS-TeP2-04: Optimizing for a Specified Target Coverage Probability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fredriksson, A

2016-06-15

Purpose: The purpose of this work is to develop a method for inverse planning of radiation therapy margins. When using this method the user specifies a desired target coverage probability and the system optimizes to meet the demand without any explicit specification of margins to handle setup uncertainty. Methods: The method determines which voxels to include in an optimization function promoting target coverage in order to achieve a specified target coverage probability. Voxels are selected in a way that retains the correlation between them: The target is displaced according to the setup errors and the voxels to include are selectedmore » as the union of the displaced target regions under the x% best scenarios according to some quality measure. The quality measure could depend on the dose to the considered structure alone or could depend on the dose to multiple structures in order to take into account correlation between structures. Results: A target coverage function was applied to the CTV of a prostate case with prescription 78 Gy and compared to conventional planning using a DVH function on the PTV. Planning was performed to achieve 90% probability of CTV coverage. The plan optimized using the coverage probability function had P(D98 > 77.95 Gy) = 0.97 for the CTV. The PTV plan using a constraint on minimum DVH 78 Gy at 90% had P(D98 > 77.95) = 0.44 for the CTV. To match the coverage probability optimization, the DVH volume parameter had to be increased to 97% which resulted in 0.5 Gy higher average dose to the rectum. Conclusion: Optimizing a target coverage probability is an easily used method to find a margin that achieves the desired coverage probability. It can lead to reduced OAR doses at the same coverage probability compared to planning with margins and DVH functions.« less
Goal-Function Tree Modeling for Systems Engineering and Fault Management

NASA Technical Reports Server (NTRS)

Johnson, Stephen B.; Breckenridge, Jonathan T.

2013-01-01

This paper describes a new representation that enables rigorous definition and decomposition of both nominal and off-nominal system goals and functions: the Goal-Function Tree (GFT). GFTs extend the concept and process of functional decomposition, utilizing state variables as a key mechanism to ensure physical and logical consistency and completeness of the decomposition of goals (requirements) and functions, and enabling full and complete traceabilitiy to the design. The GFT also provides for means to define and represent off-nominal goals and functions that are activated when the system's nominal goals are not met. The physical accuracy of the GFT, and its ability to represent both nominal and off-nominal goals enable the GFT to be used for various analyses of the system, including assessments of the completeness and traceability of system goals and functions, the coverage of fault management failure detections, and definition of system failure scenarios.
An evaluation of risk estimation procedures for mixtures of carcinogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, J.S.; Chen, J.J.

1999-12-01

The estimation of health risks from exposure to a mixture of chemical carcinogens is generally based on the combination of information from several available single compound studies. The current practice of directly summing the upper bound risk estimates of individual carcinogenic components as an upper bound on the total risk of a mixture is known to be generally too conservative. Gaylor and Chen (1996, Risk Analysis) proposed a simple procedure to compute an upper bound on the total risk using only the upper confidence limits and central risk estimates of individual carcinogens. The Gaylor-Chen procedure was derived based on anmore » underlying assumption of the normality for the distributions of individual risk estimates. IN this paper the authors evaluated the Gaylor-Chen approach in terms the coverages of the upper confidence limits on the true risks of individual carcinogens. In general, if the coverage probabilities for the individual carcinogens are all approximately equal to the nominal level, then the Gaylor-Chen approach should perform well. However, the Gaylor-Chen approach can be conservative or anti-conservative if some of all individual upper confidence limit estimates are conservative or anti-conservative.« less
Insurance premiums and insurance coverage of near-poor children.

PubMed

Hadley, Jack; Reschovsky, James D; Cunningham, Peter; Kenney, Genevieve; Dubay, Lisa

States increasingly are using premiums for near-poor children in their public insurance programs (Medicaid/SCHIP) to limit private insurance crowd-out and constrain program costs. Using national data from four rounds of the Community Tracking Study Household Surveys spanning the seven years from 1996 to 2003, this study estimates a multinomial logistic regression model examining how public and private insurance premiums affect insurance coverage outcomes (Medicaid/SCHIP coverage, private coverage, and no coverage). Higher public premiums are significantly associated with a lower probability of public coverage and higher probabilities of private coverage and uninsurance; higher private premiums are significantly related to a lower probability of private coverage and higher probabilities of public coverage and uninsurance. The results imply that uninsurance rates will rise if both public and private premiums increase, and suggest that states that impose or increase public insurance premiums for near-poor children will succeed in discouraging crowd-out of private insurance, but at the expense of higher rates of uninsurance. Sustained increases in private insurance premiums will continue to create enrollment pressures on state insurance programs for children.
A comparison of confidence interval methods for the concordance correlation coefficient and intraclass correlation coefficient with small number of raters.

PubMed

Feng, Dai; Svetnik, Vladimir; Coimbra, Alexandre; Baumgartner, Richard

2014-01-01

The intraclass correlation coefficient (ICC) with fixed raters or, equivalently, the concordance correlation coefficient (CCC) for continuous outcomes is a widely accepted aggregate index of agreement in settings with small number of raters. Quantifying the precision of the CCC by constructing its confidence interval (CI) is important in early drug development applications, in particular in qualification of biomarker platforms. In recent years, there have been several new methods proposed for construction of CIs for the CCC, but their comprehensive comparison has not been attempted. The methods consisted of the delta method and jackknifing with and without Fisher's Z-transformation, respectively, and Bayesian methods with vague priors. In this study, we carried out a simulation study, with data simulated from multivariate normal as well as heavier tailed distribution (t-distribution with 5 degrees of freedom), to compare the state-of-the-art methods for assigning CI to the CCC. When the data are normally distributed, the jackknifing with Fisher's Z-transformation (JZ) tended to provide superior coverage and the difference between it and the closest competitor, the Bayesian method with the Jeffreys prior was in general minimal. For the nonnormal data, the jackknife methods, especially the JZ method, provided the coverage probabilities closest to the nominal in contrast to the others which yielded overly liberal coverage. Approaches based upon the delta method and Bayesian method with conjugate prior generally provided slightly narrower intervals and larger lower bounds than others, though this was offset by their poor coverage. Finally, we illustrated the utility of the CIs for the CCC in an example of a wake after sleep onset (WASO) biomarker, which is frequently used in clinical sleep studies of drugs for treatment of insomnia.
Causal Mediation Analysis for the Cox Proportional Hazards Model with a Smooth Baseline Hazard Estimator.

PubMed

Wang, Wei; Albert, Jeffrey M

2017-08-01

An important problem within the social, behavioral, and health sciences is how to partition an exposure effect (e.g. treatment or risk factor) among specific pathway effects and to quantify the importance of each pathway. Mediation analysis based on the potential outcomes framework is an important tool to address this problem and we consider the estimation of mediation effects for the proportional hazards model in this paper. We give precise definitions of the total effect, natural indirect effect, and natural direct effect in terms of the survival probability, hazard function, and restricted mean survival time within the standard two-stage mediation framework. To estimate the mediation effects on different scales, we propose a mediation formula approach in which simple parametric models (fractional polynomials or restricted cubic splines) are utilized to approximate the baseline log cumulative hazard function. Simulation study results demonstrate low bias of the mediation effect estimators and close-to-nominal coverage probability of the confidence intervals for a wide range of complex hazard shapes. We apply this method to the Jackson Heart Study data and conduct sensitivity analysis to assess the impact on the mediation effects inference when the no unmeasured mediator-outcome confounding assumption is violated.
Spectral characterization of the LANDSAT Thematic Mapper sensors

NASA Technical Reports Server (NTRS)

Markham, B. L.; Barker, J. L.

1984-01-01

The spectral coverage characteristics of the two thematic mapper instruments were determined by analyses of spectral measurements of the optics, filters, and detectors. The following results are presented: (1) band 2 and 3 flatness was slightly below specification, and band 7 flatness was below specification; (2) band 5 upper-band edge was higher than specifications; (3) band 2 band edges were shifted upward about 9 nm relative to nominal; and (4) band 4, 5, and 7 lower band edges were 16 to 18 nm higher then nominal.
Assessing items on the SF-8 Japanese version for health-related quality of life: a psychometric analysis based on the nominal categories model of item response theory.

PubMed

Tokuda, Yasuharu; Okubo, Tomoya; Ohde, Sachiko; Jacobs, Joshua; Takahashi, Osamu; Omata, Fumio; Yanai, Haruo; Hinohara, Shigeaki; Fukui, Tsuguya

2009-06-01

The Short Form-8 (SF-8) questionnaire is a commonly used 8-item instrument of health-related quality of life (QOL) and provides a health profile of eight subdimensions. Our aim was to examine the psychometric properties of the Japanese version of the SF-8 instrument using methodology based on nominal categories model. Using data from an adjusted random sample from a nationally representative panel, the nominal categories modeling was applied to SF-8 items to characterize coverage of the latent trait (theta). Probabilities for response choices were described as functions on the latent trait. Information functions were generated based on the estimated item parameters. A total of 3344 participants (53%, women; median age, 35 years) provided responses. One factor was retained (eigenvalue, 4.65; variance proportion of 0.58) and used as theta. All item response category characteristic curves satisfied the monotonicity assumption in accurate order with corresponding ordinal responses. Four items (general health, bodily pain, vitality, and mental health) cover most of the spectrum of theta, while the other four items (physical function, role physical [role limitations because of physical health], social functioning, and role emotional [role limitations because of emotional problems] ) cover most of the negative range of theta. Information function for all items combined peaked at -0.7 of theta (information = 18.5) and decreased with increasing theta. The SF-8 instrument performs well among those with poor QOL across the continuum of the latent trait and thus can recognize more effectively persons with relatively poorer QOL than those with relatively better QOL.
Assessing agreement with relative area under the coverage probability curve.

PubMed

Barnhart, Huiman X

2016-08-15

There has been substantial statistical literature in the last several decades on assessing agreement, and coverage probability approach was selected as a preferred index for assessing and improving measurement agreement in a core laboratory setting. With this approach, a satisfactory agreement is based on pre-specified high satisfactory coverage probability (e.g., 95%), given one pre-specified acceptable difference. In practice, we may want to have quality control on more than one pre-specified differences, or we may simply want to summarize the agreement based on differences up to a maximum acceptable difference. We propose to assess agreement via the coverage probability curve that provides a full spectrum of measurement error at various differences/disagreement. Relative area under the coverage probability curve is proposed for the summary of overall agreement, and this new summary index can be used for comparison of different intra-methods or inter-methods/labs/observers' agreement. Simulation studies and a blood pressure example are used for illustration of the methodology. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Universal access: making health systems work for women.

PubMed

Ravindran, T K Sundari

2012-01-01

Universal coverage by health services is one of the core obligations that any legitimate government should fulfil vis-à-vis its citizens. However, universal coverage may not in itself ensure universal access to health care. Among the many challenges to ensuring universal coverage as well as access to health care are structural inequalities by caste, race, ethnicity and gender. Based on a review of published literature and applying a gender-analysis framework, this paper highlights ways in which the policies aimed at promoting universal coverage may not benefit women to the same extent as men because of gender-based differentials and inequalities in societies. It also explores how 'gender-blind' organisation and delivery of health care services may deny universal access to women even when universal coverage has been nominally achieved. The paper then makes recommendations for addressing these.
Kappa statistic for clustered matched-pair data.

PubMed

Yang, Zhao; Zhou, Ming

2014-07-10

Kappa statistic is widely used to assess the agreement between two procedures in the independent matched-pair data. For matched-pair data collected in clusters, on the basis of the delta method and sampling techniques, we propose a nonparametric variance estimator for the kappa statistic without within-cluster correlation structure or distributional assumptions. The results of an extensive Monte Carlo simulation study demonstrate that the proposed kappa statistic provides consistent estimation and the proposed variance estimator behaves reasonably well for at least a moderately large number of clusters (e.g., K ≥50). Compared with the variance estimator ignoring dependence within a cluster, the proposed variance estimator performs better in maintaining the nominal coverage probability when the intra-cluster correlation is fair (ρ ≥0.3), with more pronounced improvement when ρ is further increased. To illustrate the practical application of the proposed estimator, we analyze two real data examples of clustered matched-pair data. Copyright © 2014 John Wiley & Sons, Ltd.
Mariner Mars 9 stereophotogrammetry

NASA Technical Reports Server (NTRS)

Benesh, M.

1973-01-01

Discussion of the equipment and orbital specifications of the Mariner Mars 9 spacecraft - a Martian orbiter which was placed in orbit on Nov. 14, 1971, for an expected 50-year stay and has made possible a practically 100% photographic coverage of the planet's surface. The orbit has a nominal 12-hr period, a nominal periapsis of 1300 km, and a nominal apoapsis of 18,000 km. Many of the outstanding topographic features of the planet have been covered by the convergent stereopairs carried by the orbiter. Theoretical considerations are set forth concerning the necessary instrument orientation and rotation requirements to achieve such performance levels in this extraterrestrial application of photogrammetry. The photogrammetric method used in this mission is assessed as useful in the evaluation of outstanding Martian features such as the mammoth volcano of the Nix Olympica region.
Confidence intervals and sample size calculations for the standardized mean difference effect size between two normal populations under heteroscedasticity.

PubMed

Shieh, G

2013-12-01

The use of effect sizes and associated confidence intervals in all empirical research has been strongly emphasized by journal publication guidelines. To help advance theory and practice in the social sciences, this article describes an improved procedure for constructing confidence intervals of the standardized mean difference effect size between two independent normal populations with unknown and possibly unequal variances. The presented approach has advantages over the existing formula in both theoretical justification and computational simplicity. In addition, simulation results show that the suggested one- and two-sided confidence intervals are more accurate in achieving the nominal coverage probability. The proposed estimation method provides a feasible alternative to the most commonly used measure of Cohen's d and the corresponding interval procedure when the assumption of homogeneous variances is not tenable. To further improve the potential applicability of the suggested methodology, the sample size procedures for precise interval estimation of the standardized mean difference are also delineated. The desired precision of a confidence interval is assessed with respect to the control of expected width and to the assurance probability of interval width within a designated value. Supplementary computer programs are developed to aid in the usefulness and implementation of the introduced techniques.
Premium growth and its effect on employer-sponsored insurance.

PubMed

Vistnes, Jessica; Selden, Thomas

2011-03-01

We use variation in premium inflation and general inflation across geographic areas to identify the effects of downward nominal wage rigidity on employers' health insurance decisions. Using employer level data from the 2000 to 2005 Medical Expenditure Panel Survey-Insurance Component, we examine the effect of premium growth on the likelihood that an employer offers insurance, eligibility rates among employees, continuous measures of employee premium contributions for both single and family coverage, and deductibles. We find that small, low-wage employers are less likely to offer health insurance in response to increased premium inflation, and if they do offer coverage they increase employee contributions and deductible levels. In contrast, larger, low-wage employers maintain their offers of coverage, but reduce eligibility for such coverage. They also increase employee contributions for single and family coverage, but not deductibles. Among high-wage employers, all but the largest increase deductibles in response to cost pressures.
A Max-Flow Based Algorithm for Connected Target Coverage with Probabilistic Sensors

PubMed Central

Shan, Anxing; Xu, Xianghua; Cheng, Zongmao; Wang, Wensheng

2017-01-01

Coverage is a fundamental issue in the research field of wireless sensor networks (WSNs). Connected target coverage discusses the sensor placement to guarantee the needs of both coverage and connectivity. Existing works largely leverage on the Boolean disk model, which is only a coarse approximation to the practical sensing model. In this paper, we focus on the connected target coverage issue based on the probabilistic sensing model, which can characterize the quality of coverage more accurately. In the probabilistic sensing model, sensors are only be able to detect a target with certain probability. We study the collaborative detection probability of target under multiple sensors. Armed with the analysis of collaborative detection probability, we further formulate the minimum ϵ-connected target coverage problem, aiming to minimize the number of sensors satisfying the requirements of both coverage and connectivity. We map it into a flow graph and present an approximation algorithm called the minimum vertices maximum flow algorithm (MVMFA) with provable time complex and approximation ratios. To evaluate our design, we analyze the performance of MVMFA theoretically and also conduct extensive simulation studies to demonstrate the effectiveness of our proposed algorithm. PMID:28587084
A Max-Flow Based Algorithm for Connected Target Coverage with Probabilistic Sensors.

PubMed

Shan, Anxing; Xu, Xianghua; Cheng, Zongmao; Wang, Wensheng

2017-05-25

Coverage is a fundamental issue in the research field of wireless sensor networks (WSNs). Connected target coverage discusses the sensor placement to guarantee the needs of both coverage and connectivity. Existing works largely leverage on the Boolean disk model, which is only a coarse approximation to the practical sensing model. In this paper, we focus on the connected target coverage issue based on the probabilistic sensing model, which can characterize the quality of coverage more accurately. In the probabilistic sensing model, sensors are only be able to detect a target with certain probability. We study the collaborative detection probability of target under multiple sensors. Armed with the analysis of collaborative detection probability, we further formulate the minimum ϵ -connected target coverage problem, aiming to minimize the number of sensors satisfying the requirements of both coverage and connectivity. We map it into a flow graph and present an approximation algorithm called the minimum vertices maximum flow algorithm (MVMFA) with provable time complex and approximation ratios. To evaluate our design, we analyze the performance of MVMFA theoretically and also conduct extensive simulation studies to demonstrate the effectiveness of our proposed algorithm.
Selective robust optimization: A new intensity-modulated proton therapy optimization strategy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yupeng; Niemela, Perttu; Siljamaki, Sami

2015-08-15

Purpose: To develop a new robust optimization strategy for intensity-modulated proton therapy as an important step in translating robust proton treatment planning from research to clinical applications. Methods: In selective robust optimization, a worst-case-based robust optimization algorithm is extended, and terms of the objective function are selectively computed from either the worst-case dose or the nominal dose. Two lung cancer cases and one head and neck cancer case were used to demonstrate the practical significance of the proposed robust planning strategy. The lung cancer cases had minimal tumor motion less than 5 mm, and, for the demonstration of the methodology,more » are assumed to be static. Results: Selective robust optimization achieved robust clinical target volume (CTV) coverage and at the same time increased nominal planning target volume coverage to 95.8%, compared to the 84.6% coverage achieved with CTV-based robust optimization in one of the lung cases. In the other lung case, the maximum dose in selective robust optimization was lowered from a dose of 131.3% in the CTV-based robust optimization to 113.6%. Selective robust optimization provided robust CTV coverage in the head and neck case, and at the same time improved controls over isodose distribution so that clinical requirements may be readily met. Conclusions: Selective robust optimization may provide the flexibility and capability necessary for meeting various clinical requirements in addition to achieving the required plan robustness in practical proton treatment planning settings.« less
Peer clustering of exercise and eating behaviours among young adults in Sweden: a cross-sectional study of egocentric network data

PubMed Central

2013-01-01

Background Research suggests that the growing prevalence of obesity may be related to the influence of the health behaviours of peers. We look at clustering of exercise and eating behaviours amongst a previously unstudied group, young adults in Sweden. Previous research has mainly been conducted in the United States and Britain, countries that have relatively high rates of obesity. Methods Using ego-alter dyads from the egocentric network data as the unit of analysis, we conduct logistic regressions to investigate the association between ego and alter exercise and eating behaviours. Results Respondents have a significantly greater probability of engaging in regular exercise and eating healthily if a nominated peer also does so. Furthermore, the degree to which this behavior is shared is modulated by the strength of the relationship between the two individuals, with a greater probability of engaging in these behaviours observed when the relationship with the nominated peer is strong relative to when the relationship is weak. However, we find that ego-alter homogeneity in terms of gender and migration status was not associated with a significantly greater probability of behaving in a similar manner to a nominated peer. Furthermore, the status of the nominated peer as a relative or not did not impact the probability that the ego would engage in similar health behaviours to that alter. Conclusions We observe strong associations between ego and alter health behaviours for young adults, consistent with previous research. Although we cannot draw causal inferences, these results suggest that the health behaviours of an individual’s peers may play a role in shaping their own health behaviours. PMID:23981951
Peer clustering of exercise and eating behaviours among young adults in Sweden: a cross-sectional study of egocentric network data.

PubMed

Barclay, Kieron J; Edling, Christofer; Rydgren, Jens

2013-08-28

Research suggests that the growing prevalence of obesity may be related to the influence of the health behaviours of peers. We look at clustering of exercise and eating behaviours amongst a previously unstudied group, young adults in Sweden. Previous research has mainly been conducted in the United States and Britain, countries that have relatively high rates of obesity. Using ego-alter dyads from the egocentric network data as the unit of analysis, we conduct logistic regressions to investigate the association between ego and alter exercise and eating behaviours. Respondents have a significantly greater probability of engaging in regular exercise and eating healthily if a nominated peer also does so. Furthermore, the degree to which this behavior is shared is modulated by the strength of the relationship between the two individuals, with a greater probability of engaging in these behaviours observed when the relationship with the nominated peer is strong relative to when the relationship is weak. However, we find that ego-alter homogeneity in terms of gender and migration status was not associated with a significantly greater probability of behaving in a similar manner to a nominated peer. Furthermore, the status of the nominated peer as a relative or not did not impact the probability that the ego would engage in similar health behaviours to that alter. We observe strong associations between ego and alter health behaviours for young adults, consistent with previous research. Although we cannot draw causal inferences, these results suggest that the health behaviours of an individual's peers may play a role in shaping their own health behaviours.
Aviation Safety: Modeling and Analyzing Complex Interactions between Humans and Automated Systems

NASA Technical Reports Server (NTRS)

Rungta, Neha; Brat, Guillaume; Clancey, William J.; Linde, Charlotte; Raimondi, Franco; Seah, Chin; Shafto, Michael

2013-01-01

The on-going transformation from the current US Air Traffic System (ATS) to the Next Generation Air Traffic System (NextGen) will force the introduction of new automated systems and most likely will cause automation to migrate from ground to air. This will yield new function allocations between humans and automation and therefore change the roles and responsibilities in the ATS. Yet, safety in NextGen is required to be at least as good as in the current system. We therefore need techniques to evaluate the safety of the interactions between humans and automation. We think that current human factor studies and simulation-based techniques will fall short in front of the ATS complexity, and that we need to add more automated techniques to simulations, such as model checking, which offers exhaustive coverage of the non-deterministic behaviors in nominal and off-nominal scenarios. In this work, we present a verification approach based both on simulations and on model checking for evaluating the roles and responsibilities of humans and automation. Models are created using Brahms (a multi-agent framework) and we show that the traditional Brahms simulations can be integrated with automated exploration techniques based on model checking, thus offering a complete exploration of the behavioral space of the scenario. Our formal analysis supports the notion of beliefs and probabilities to reason about human behavior. We demonstrate the technique with the Ueberligen accident since it exemplifies authority problems when receiving conflicting advices from human and automated systems.

High-frame-rate full-vocal-tract 3D dynamic speech imaging.

PubMed

Fu, Maojing; Barlaz, Marissa S; Holtrop, Joseph L; Perry, Jamie L; Kuehn, David P; Shosted, Ryan K; Liang, Zhi-Pei; Sutton, Bradley P

2017-04-01

To achieve high temporal frame rate, high spatial resolution and full-vocal-tract coverage for three-dimensional dynamic speech MRI by using low-rank modeling and sparse sampling. Three-dimensional dynamic speech MRI is enabled by integrating a novel data acquisition strategy and an image reconstruction method with the partial separability model: (a) a self-navigated sparse sampling strategy that accelerates data acquisition by collecting high-nominal-frame-rate cone navigator sand imaging data within a single repetition time, and (b) are construction method that recovers high-quality speech dynamics from sparse (k,t)-space data by enforcing joint low-rank and spatiotemporal total variation constraints. The proposed method has been evaluated through in vivo experiments. A nominal temporal frame rate of 166 frames per second (defined based on a repetition time of 5.99 ms) was achieved for an imaging volume covering the entire vocal tract with a spatial resolution of 2.2 × 2.2 × 5.0 mm 3 . Practical utility of the proposed method was demonstrated via both validation experiments and a phonetics investigation. Three-dimensional dynamic speech imaging is possible with full-vocal-tract coverage, high spatial resolution and high nominal frame rate to provide dynamic speech data useful for phonetic studies. Magn Reson Med 77:1619-1629, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.
Epitaxial growth of Ag on W(110)

NASA Astrophysics Data System (ADS)

Deisl, C.; Bertel, E.; Bürgener, M.; Meister, G.; Goldmann, A.

2005-10-01

Epitaxial growth of Ag on W(110) at room temperature was studied by scanning tunneling microscopy (STM) and polarization-dependent photoemission. At coverages far below one monolayer Ag atoms populate bcc sites of the substrate and form close-packed islands of monolayer thickness. With increasing coverage geometrical misfit between Ag(111)-like layers and W(110) generates surface stress along W[11¯0] . This is released by formation of domain walls parallel W[001] which are observed with a distance between about 25Å and 30Å , depending on the details of the growth process. At one monolayer coverage most of the Ag atoms still reside in or very near to bcc substrate positions, but now the strain release pattern is changed: solitons aligned along W[1¯12] are formed at an average distance between 35Å and 50Å . The details of the soliton arrangement depend critically on the degree of equilibration and the presence of holes in the monolayer film which allow an additional stress release. This is evident from a comparison with results of STM studies performed at the closed and carefully annealed Ag monolayer [Kim , Phys. Rev. B 67, 223401 (2003)]. Further deposition of Ag starts growth of a second monolayer by formation of islands which increase in size with coverage. At a nominal coverage of 1.5 monolayers the strain relieve pattern changes again: some corrugation lines are oriented along W[001] as in the submonolayers, but other orientations related to Ag(111) directions appear as well. This indicates that several possibilities are available at similar energy costs and that the transition from the W substrate potential to a Ag potential seen by the second layer is very soft. Finally at a nominal coverage of several monolayers, Stranski-Krastanov growth is observed producing Ag(111)-like terraces with one of the dense-packed Ag rows oriented parallel to W[11¯1] .
Bundled automobile insurance coverage and accidents.

PubMed

Li, Chu-Shiu; Liu, Chwen-Chi; Peng, Sheng-Chang

2013-01-01

This paper investigates the characteristics of automobile accidents by taking into account two types of automobile insurance coverage: comprehensive vehicle physical damage insurance and voluntary third-party liability insurance. By using a unique data set in the Taiwanese automobile insurance market, we explore the bundled automobile insurance coverage and the occurrence of claims. It is shown that vehicle physical damage insurance is the major automobile coverage and affects the decision to purchase voluntary liability insurance coverage as a complement. Moreover, policyholders with high vehicle physical damage insurance coverage have a significantly higher probability of filing vehicle damage claims, and if they additionally purchase low voluntary liability insurance coverage, their accident claims probability is higher than those who purchase high voluntary liability insurance coverage. Our empirical results reveal that additional automobile insurance coverage information can capture more driver characteristics and driving behaviors to provide useful information for insurers' underwriting policies and to help analyze the occurrence of automobile accidents. Copyright © 2012 Elsevier Ltd. All rights reserved.
Target Coverage in Wireless Sensor Networks with Probabilistic Sensors

PubMed Central

Shan, Anxing; Xu, Xianghua; Cheng, Zongmao

2016-01-01

Sensing coverage is a fundamental problem in wireless sensor networks (WSNs), which has attracted considerable attention. Conventional research on this topic focuses on the 0/1 coverage model, which is only a coarse approximation to the practical sensing model. In this paper, we study the target coverage problem, where the objective is to find the least number of sensor nodes in randomly-deployed WSNs based on the probabilistic sensing model. We analyze the joint detection probability of target with multiple sensors. Based on the theoretical analysis of the detection probability, we formulate the minimum ϵ-detection coverage problem. We prove that the minimum ϵ-detection coverage problem is NP-hard and present an approximation algorithm called the Probabilistic Sensor Coverage Algorithm (PSCA) with provable approximation ratios. To evaluate our design, we analyze the performance of PSCA theoretically and also perform extensive simulations to demonstrate the effectiveness of our proposed algorithm. PMID:27618902
Coverage-based constraints for IMRT optimization

NASA Astrophysics Data System (ADS)

Mescher, H.; Ulrich, S.; Bangert, M.

2017-09-01

Radiation therapy treatment planning requires an incorporation of uncertainties in order to guarantee an adequate irradiation of the tumor volumes. In current clinical practice, uncertainties are accounted for implicitly with an expansion of the target volume according to generic margin recipes. Alternatively, it is possible to account for uncertainties by explicit minimization of objectives that describe worst-case treatment scenarios, the expectation value of the treatment or the coverage probability of the target volumes during treatment planning. In this note we show that approaches relying on objectives to induce a specific coverage of the clinical target volumes are inevitably sensitive to variation of the relative weighting of the objectives. To address this issue, we introduce coverage-based constraints for intensity-modulated radiation therapy (IMRT) treatment planning. Our implementation follows the concept of coverage-optimized planning that considers explicit error scenarios to calculate and optimize patient-specific probabilities q(\\hat{d}, \\hat{v}) of covering a specific target volume fraction \\hat{v} with a certain dose \\hat{d} . Using a constraint-based reformulation of coverage-based objectives we eliminate the trade-off between coverage and competing objectives during treatment planning. In-depth convergence tests including 324 treatment plan optimizations demonstrate the reliability of coverage-based constraints for varying levels of probability, dose and volume. General clinical applicability of coverage-based constraints is demonstrated for two cases. A sensitivity analysis regarding penalty variations within this planing study based on IMRT treatment planning using (1) coverage-based constraints, (2) coverage-based objectives, (3) probabilistic optimization, (4) robust optimization and (5) conventional margins illustrates the potential benefit of coverage-based constraints that do not require tedious adjustment of target volume objectives.
78 FR 21908 - Request for Nominations of Members To Serve on the National Advisory Committee on Racial, Ethnic...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-12

... impacting Census survey design and implementation. The Advisory Committee discusses census policies... to the Director of the Census Bureau on the full spectrum of Census surveys and programs. The... communication strategies to reduce program/survey costs, improve coverage and operational efficiency, improve...
Antenna and propagation studies for spacecraft systems: Addendum to preflight SL-1/SL-3 Skylab VHF ranging coverage (early and late TPI)

NASA Technical Reports Server (NTRS)

Eisenhauer, D. R.; James, D. A.

1973-01-01

A preflight assessment is presented of the expected Skylab VHF ranging coverage for the rendezvous portion of the SL-1/SL-3 mission, assuming a 28 July 1973 launch date, for the alternative trajectory cases characterized by either an early TPI or a late TPI. In this assessment early TPI and late TPI are used to indicate a TPI maneuver occurring 10 minutes prior to or after the nominally scheduled TPI maneuver, respectively. The Saturn workshop (SWS) maintains a solar inertial (SI) attitude throughout rendezvous for both trajectory cases. The results summarized concern VHF ranging function performance during that period most likely to be affected by off-nominal TPI conditions, i.e., NSR (5:56 g.e.t.) to station keeping. Curves are presented which show the variation in received power levels on both spacecraft-to-spacecraft links from about 100 n.mi. range to CSM and SWS station keeping. Appropriate threshold levels are shown on these received power curves to indicate zero circuit margins for the ranging function.
Immigrants and Employer-Sponsored Health Insurance

PubMed Central

Buchmueller, Thomas C; Lo Sasso, Anthony T; Lurie, Ithai; Dolfin, Sarah

2007-01-01

Objective To investigate the factors underlying the lower rate of employer-sponsored health insurance coverage for foreign-born workers. Data Sources 2001 Survey of Income and Program Participation. Study Design We estimate probit regressions to determine the effect of immigrant status on employer-sponsored health insurance coverage, including the probabilities of working for a firm that offers coverage, being eligible for coverage, and taking up coverage. Data Extraction Methods We identified native born citizens, naturalized citizens, and noncitizen residents between the ages of 18 and 65, in the year 2002. Principal Findings First, we find that the large difference in coverage rates for immigrants and native-born Americans is driven by the very low rates of coverage for noncitizen immigrants. Differences between native-born and naturalized citizens are quite small and for some outcomes are statistically insignificant when we control for observable characteristics. Second, our results indicate that the gap between natives and noncitizens is explained mainly by differences in the probability of working for a firm that offers insurance. Conditional on working for such a firm, noncitizens are only slightly less likely to be eligible for coverage and, when eligible, are only slightly less likely to take up coverage. Third, roughly two-thirds of the native/noncitizen gap in coverage overall and in the probability of working for an insurance-providing employer is explained by characteristics of the individual and differences in the types of jobs they hold. Conclusions The substantially higher rate of uninsurance among immigrants is driven by the lower rate of health insurance offers by the employers of immigrants. PMID:17355593
Comparison of variance estimators for meta-analysis of instrumental variable estimates

PubMed Central

Schmidt, AF; Hingorani, AD; Jefferis, BJ; White, J; Groenwold, RHH; Dudbridge, F

2016-01-01

Abstract Background: Mendelian randomization studies perform instrumental variable (IV) analysis using genetic IVs. Results of individual Mendelian randomization studies can be pooled through meta-analysis. We explored how different variance estimators influence the meta-analysed IV estimate. Methods: Two versions of the delta method (IV before or after pooling), four bootstrap estimators, a jack-knife estimator and a heteroscedasticity-consistent (HC) variance estimator were compared using simulation. Two types of meta-analyses were compared, a two-stage meta-analysis pooling results, and a one-stage meta-analysis pooling datasets. Results: Using a two-stage meta-analysis, coverage of the point estimate using bootstrapped estimators deviated from nominal levels at weak instrument settings and/or outcome probabilities ≤ 0.10. The jack-knife estimator was the least biased resampling method, the HC estimator often failed at outcome probabilities ≤ 0.50 and overall the delta method estimators were the least biased. In the presence of between-study heterogeneity, the delta method before meta-analysis performed best. Using a one-stage meta-analysis all methods performed equally well and better than two-stage meta-analysis of greater or equal size. Conclusions: In the presence of between-study heterogeneity, two-stage meta-analyses should preferentially use the delta method before meta-analysis. Weak instrument bias can be reduced by performing a one-stage meta-analysis. PMID:27591262
A comparison of confidence interval methods for the intraclass correlation coefficient in community-based cluster randomization trials with a binary outcome.

PubMed

Braschel, Melissa C; Svec, Ivana; Darlington, Gerarda A; Donner, Allan

2016-04-01

Many investigators rely on previously published point estimates of the intraclass correlation coefficient rather than on their associated confidence intervals to determine the required size of a newly planned cluster randomized trial. Although confidence interval methods for the intraclass correlation coefficient that can be applied to community-based trials have been developed for a continuous outcome variable, fewer methods exist for a binary outcome variable. The aim of this study is to evaluate confidence interval methods for the intraclass correlation coefficient applied to binary outcomes in community intervention trials enrolling a small number of large clusters. Existing methods for confidence interval construction are examined and compared to a new ad hoc approach based on dividing clusters into a large number of smaller sub-clusters and subsequently applying existing methods to the resulting data. Monte Carlo simulation is used to assess the width and coverage of confidence intervals for the intraclass correlation coefficient based on Smith's large sample approximation of the standard error of the one-way analysis of variance estimator, an inverted modified Wald test for the Fleiss-Cuzick estimator, and intervals constructed using a bootstrap-t applied to a variance-stabilizing transformation of the intraclass correlation coefficient estimate. In addition, a new approach is applied in which clusters are randomly divided into a large number of smaller sub-clusters with the same methods applied to these data (with the exception of the bootstrap-t interval, which assumes large cluster sizes). These methods are also applied to a cluster randomized trial on adolescent tobacco use for illustration. When applied to a binary outcome variable in a small number of large clusters, existing confidence interval methods for the intraclass correlation coefficient provide poor coverage. However, confidence intervals constructed using the new approach combined with Smith's method provide nominal or close to nominal coverage when the intraclass correlation coefficient is small (<0.05), as is the case in most community intervention trials. This study concludes that when a binary outcome variable is measured in a small number of large clusters, confidence intervals for the intraclass correlation coefficient may be constructed by dividing existing clusters into sub-clusters (e.g. groups of 5) and using Smith's method. The resulting confidence intervals provide nominal or close to nominal coverage across a wide range of parameters when the intraclass correlation coefficient is small (<0.05). Application of this method should provide investigators with a better understanding of the uncertainty associated with a point estimator of the intraclass correlation coefficient used for determining the sample size needed for a newly designed community-based trial. © The Author(s) 2015.
Emirates Mars Mission Planetary Protection Plan

NASA Astrophysics Data System (ADS)

Awadhi, Mohsen Al

2016-07-01

The United Arab Emirates is planning to launch a spacecraft to Mars in 2020 as part of the Emirates Mars Mission (EMM). The EMM spacecraft, Amal, will arrive in early 2021 and enter orbit about Mars. Through a sequence of subsequent maneuvers, the spacecraft will enter a large science orbit and remain there throughout the primary mission. This paper describes the planetary protection plan for the EMM mission. The EMM science orbit, where Amal will conduct the majority of its operations, is very large compared to other Mars orbiters. The nominal orbit has a periapse altitude of 20,000 km, an apoapse altitude of 43,000 km, and an inclination of 25 degrees. From this vantage point, Amal will conduct a series of atmospheric investigations. Since Amal's orbit is very large, the planetary protection plan is to demonstrate a very low probability that the spacecraft will ever encounter Mars' surface or lower atmosphere during the mission. The EMM team has prepared methods to demonstrate that (1) the launch vehicle targets support a 0.01% probability of impacting Mars, or less, within 50 years; (2) the spacecraft has a 1% probability or less of impacting Mars during 20 years; and (3) the spacecraft has a 5% probability or less of impacting Mars during 50 years. The EMM mission design resembles the mission design of many previous missions, differing only in the specific parameters and final destination. The following sequence describes the mission: 1.The mission will launch in July, 2020. The launch includes a brief parking orbit and a direct injection to the interplanetary cruise. The launch targets are specified by the hyperbolic departure's energy C3, and the hyperbolic departure's direction in space, captured by the right ascension and declination of the launch asymptote, RLA and DLA, respectively. The targets of the launch vehicle are biased away from Mars such that there is a 0.01% probability or less that the launch vehicle arrives onto a trajectory that impacts Mars. 2.The spacecraft is deployed from the launch vehicle and powers on. 3.Within the first month, the spacecraft executes a trajectory correction maneuver to remove the launch bias. The target of this maneuver may still have a small bias to further reduce the probability of inadvertently impacting Mars. 4.Four additional trajectory correction maneuvers are scheduled and planned in the interplanetary cruise in order to target the precise arrival conditions at Mars. The targeted arrival conditions are specified by an altitude above the surface of Mars and an inclination relative to Mars' equator. The closest approach to Mars during the Mars Orbit Insertion (MOI) is over 600 km and the periapsis altitude of the first orbit about Mars is nominally 500 km. The inclination of the first orbit about Mars is nominally around 18 degrees. 5.The Mars Orbit Insertion is performed as a pitch-over burn, approaching no closer than approximately 600 km, and targeting a capture orbit period of 35-40 hours. 6.The spacecraft Capture Orbit has a nominal periapse altitude of 500 km, a nominal apoapse altitude of approximately 45,000 km, and a nominal period of approximately 35 hours. The mission expects that this orbit will be somewhat different after executing the real MOI due to maneuver execution errors. The full range of expected Capture Orbit sizes is acceptable from a planetary protection perspective. 7.The spacecraft remains in the Capture Orbit for two months. 8.The spacecraft then executes three maneuvers in the Transition to Science phase, raising the orbital periapse, raising the orbit inclination, adjusting the apoapse, and placing the argument of periapse near a value of 177 deg. The three maneuvers are nominally one week apart. The first maneuver is large and will raise the periapse significantly, thereafter significantly reducing the probability of Amal impacting Mars in the future.
Review of probabilistic analysis of dynamic response of systems with random parameters

NASA Technical Reports Server (NTRS)

Kozin, F.; Klosner, J. M.

1989-01-01

The various methods that have been studied in the past to allow probabilistic analysis of dynamic response for systems with random parameters are reviewed. Dynamic response may have been obtained deterministically if the variations about the nominal values were small; however, for space structures which require precise pointing, the variations about the nominal values of the structural details and of the environmental conditions are too large to be considered as negligible. These uncertainties are accounted for in terms of probability distributions about their nominal values. The quantities of concern for describing the response of the structure includes displacements, velocities, and the distributions of natural frequencies. The exact statistical characterization of the response would yield joint probability distributions for the response variables. Since the random quantities will appear as coefficients, determining the exact distributions will be difficult at best. Thus, certain approximations will have to be made. A number of techniques that are available are discussed, even in the nonlinear case. The methods that are described were: (1) Liouville's equation; (2) perturbation methods; (3) mean square approximate systems; and (4) nonlinear systems with approximation by linear systems.
Properties of model-averaged BMDLs: a study of model averaging in dichotomous response risk estimation.

PubMed

Wheeler, Matthew W; Bailer, A John

2007-06-01

Model averaging (MA) has been proposed as a method of accounting for model uncertainty in benchmark dose (BMD) estimation. The technique has been used to average BMD dose estimates derived from dichotomous dose-response experiments, microbial dose-response experiments, as well as observational epidemiological studies. While MA is a promising tool for the risk assessor, a previous study suggested that the simple strategy of averaging individual models' BMD lower limits did not yield interval estimators that met nominal coverage levels in certain situations, and this performance was very sensitive to the underlying model space chosen. We present a different, more computationally intensive, approach in which the BMD is estimated using the average dose-response model and the corresponding benchmark dose lower bound (BMDL) is computed by bootstrapping. This method is illustrated with TiO(2) dose-response rat lung cancer data, and then systematically studied through an extensive Monte Carlo simulation. The results of this study suggest that the MA-BMD, estimated using this technique, performs better, in terms of bias and coverage, than the previous MA methodology. Further, the MA-BMDL achieves nominal coverage in most cases, and is superior to picking the "best fitting model" when estimating the benchmark dose. Although these results show utility of MA for benchmark dose risk estimation, they continue to highlight the importance of choosing an adequate model space as well as proper model fit diagnostics.
Galileo Probe forebody thermal protection

NASA Technical Reports Server (NTRS)

Green, M. J.; Davy, W. C.

1981-01-01

Material response solutions for the forebody heat shield on the candidate 310-kg Galileo Probe are presented. A charring material ablation analysis predicts thermochemical surface recession, insulation thickness, and total required heat shield mass. Benchmark shock layer solutions provide the imposed entry heating environments on the ablating surface. Heat shield sizing results are given for a nominal entry into modeled nominal and cool-heavy Jovian atmospheres, and for two heat-shield property models. The nominally designed heat shield requires a mass of at least 126 kg and would require an additional 13 kg to survive entry into the less probable cool-heavy atmosphere. The material-property model with a 30% surface reflectance reduces these mass requirements by as much as 16%.
Improving the Yule-Nielsen modified Neugebauer model by dot surface coverages depending on the ink superposition conditions

NASA Astrophysics Data System (ADS)

Hersch, Roger David; Crété, Frédérique

2004-12-01

Dot gain is different when dots are printed alone, printed in superposition with one ink or printed in superposition with two inks. In addition, the dot gain may also differ depending on which solid ink the considered halftone layer is superposed. In a previous research project, we developed a model for computing the effective surface coverage of a dot according to its superposition conditions. In the present contribution, we improve the Yule-Nielsen modified Neugebauer model by integrating into it our effective dot surface coverage computation model. Calibration of the reproduction curves mapping nominal to effective surface coverages in every superposition condition is carried out by fitting effective dot surfaces which minimize the sum of square differences between the measured reflection density spectra and reflection density spectra predicted according to the Yule-Nielsen modified Neugebauer model. In order to predict the reflection spectrum of a patch, its known nominal surface coverage values are converted into effective coverage values by weighting the contributions from different reproduction curves according to the weights of the contributing superposition conditions. We analyze the colorimetric prediction improvement brought by our extended dot surface coverage model for clustered-dot offset prints, thermal transfer prints and ink-jet prints. The color differences induced by the differences between measured reflection spectra and reflection spectra predicted according to the new dot surface estimation model are quantified on 729 different cyan, magenta, yellow patches covering the full color gamut. As a reference, these differences are also computed for the classical Yule-Nielsen modified spectral Neugebauer model incorporating a single halftone reproduction curve for each ink. Taking into account dot surface coverages according to different superposition conditions considerably improves the predictions of the Yule-Nielsen modified Neugebauer model. In the case of offset prints, the mean difference between predictions and measurements expressed in CIE-LAB CIE-94 ΔE94 values is reduced at 100 lpi from 1.54 to 0.90 (accuracy improvement factor: 1.7) and at 150 lpi it is reduced from 1.87 to 1.00 (accuracy improvement factor: 1.8). Similar improvements have been observed for a thermal transfer printer at 600 dpi, at lineatures of 50 and 75 lpi. In the case of an ink-jet printer at 600 dpi, the mean ΔE94 value is reduced at 75 lpi from 3.03 to 0.90 (accuracy improvement factor: 3.4) and at 100 lpi from 3.08 to 0.91 (accuracy improvement factor: 3.4).
Improving the Yule-Nielsen modified Neugebauer model by dot surface coverages depending on the ink superposition conditions

NASA Astrophysics Data System (ADS)

Hersch, Roger David; Crete, Frederique

2005-01-01

Dot gain is different when dots are printed alone, printed in superposition with one ink or printed in superposition with two inks. In addition, the dot gain may also differ depending on which solid ink the considered halftone layer is superposed. In a previous research project, we developed a model for computing the effective surface coverage of a dot according to its superposition conditions. In the present contribution, we improve the Yule-Nielsen modified Neugebauer model by integrating into it our effective dot surface coverage computation model. Calibration of the reproduction curves mapping nominal to effective surface coverages in every superposition condition is carried out by fitting effective dot surfaces which minimize the sum of square differences between the measured reflection density spectra and reflection density spectra predicted according to the Yule-Nielsen modified Neugebauer model. In order to predict the reflection spectrum of a patch, its known nominal surface coverage values are converted into effective coverage values by weighting the contributions from different reproduction curves according to the weights of the contributing superposition conditions. We analyze the colorimetric prediction improvement brought by our extended dot surface coverage model for clustered-dot offset prints, thermal transfer prints and ink-jet prints. The color differences induced by the differences between measured reflection spectra and reflection spectra predicted according to the new dot surface estimation model are quantified on 729 different cyan, magenta, yellow patches covering the full color gamut. As a reference, these differences are also computed for the classical Yule-Nielsen modified spectral Neugebauer model incorporating a single halftone reproduction curve for each ink. Taking into account dot surface coverages according to different superposition conditions considerably improves the predictions of the Yule-Nielsen modified Neugebauer model. In the case of offset prints, the mean difference between predictions and measurements expressed in CIE-LAB CIE-94 ΔE94 values is reduced at 100 lpi from 1.54 to 0.90 (accuracy improvement factor: 1.7) and at 150 lpi it is reduced from 1.87 to 1.00 (accuracy improvement factor: 1.8). Similar improvements have been observed for a thermal transfer printer at 600 dpi, at lineatures of 50 and 75 lpi. In the case of an ink-jet printer at 600 dpi, the mean ΔE94 value is reduced at 75 lpi from 3.03 to 0.90 (accuracy improvement factor: 3.4) and at 100 lpi from 3.08 to 0.91 (accuracy improvement factor: 3.4).
The probability of being identified as an outlier with commonly used funnel plot control limits for the standardised mortality ratio.

PubMed

Seaton, Sarah E; Manktelow, Bradley N

2012-07-16

Emphasis is increasingly being placed on the monitoring of clinical outcomes for health care providers. Funnel plots have become an increasingly popular graphical methodology used to identify potential outliers. It is assumed that a provider only displaying expected random variation (i.e. 'in-control') will fall outside a control limit with a known probability. In reality, the discrete count nature of these data, and the differing methods, can lead to true probabilities quite different from the nominal value. This paper investigates the true probability of an 'in control' provider falling outside control limits for the Standardised Mortality Ratio (SMR). The true probabilities of an 'in control' provider falling outside control limits for the SMR were calculated and compared for three commonly used limits: Wald confidence interval; 'exact' confidence interval; probability-based prediction interval. The probability of falling above the upper limit, or below the lower limit, often varied greatly from the nominal value. This was particularly apparent when there were a small number of expected events: for expected events ≤ 50 the median probability of an 'in-control' provider falling above the upper 95% limit was 0.0301 (Wald), 0.0121 ('exact'), 0.0201 (prediction). It is important to understand the properties and probability of being identified as an outlier by each of these different methods to aid the correct identification of poorly performing health care providers. The limits obtained using probability-based prediction limits have the most intuitive interpretation and their properties can be defined a priori. Funnel plot control limits for the SMR should not be based on confidence intervals.
National Immunization Program: Computerized System as a tool for new challenges

PubMed Central

Sato, Ana Paula Sayuri

2015-01-01

The scope and coverage of the Brazilian Immunization Program can be compared with those in developed countries because it provides a large number of vaccines and has a considerable coverage. The increasing complexity of the program brings challenges regarding its development, high coverage levels, access equality, and safety. The Immunization Information System, with nominal data, is an innovative tool that can more accurately monitor these indicators and allows the evaluation of the impact of new vaccination strategies. The main difficulties for such a system are in its implementation process, training of professionals, mastering its use, its constant maintenance needs and ensuring the information contained remain confidential. Therefore, encouraging the development of this tool should be part of public health policies and should also be involved in the three spheres of government as well as the public and private vaccination services. PMID:26176746
Heterogeneity in the spread and control of infectious disease: consequences for the elimination of canine rabies

NASA Astrophysics Data System (ADS)

Ferguson, Elaine A.; Hampson, Katie; Cleaveland, Sarah; Consunji, Ramona; Deray, Raffy; Friar, John; Haydon, Daniel T.; Jimenez, Joji; Pancipane, Marlon; Townsend, Sunny E.

2015-12-01

Understanding the factors influencing vaccination campaign effectiveness is vital in designing efficient disease elimination programmes. We investigated the importance of spatial heterogeneity in vaccination coverage and human-mediated dog movements for the elimination of endemic canine rabies by mass dog vaccination in Region VI of the Philippines (Western Visayas). Household survey data was used to parameterise a spatially-explicit rabies transmission model with realistic dog movement and vaccination coverage scenarios, assuming a basic reproduction number for rabies drawn from the literature. This showed that heterogeneous vaccination reduces elimination prospects relative to homogeneous vaccination at the same overall level. Had the three vaccination campaigns completed in Region VI in 2010-2012 been homogeneous, they would have eliminated rabies with high probability. However, given the observed heterogeneity, three further campaigns may be required to achieve elimination with probability 0.95. We recommend that heterogeneity be reduced in future campaigns through targeted efforts in low coverage areas, even at the expense of reduced coverage in previously high coverage areas. Reported human-mediated dog movements did not reduce elimination probability, so expending limited resources on restricting dog movements is unnecessary in this endemic setting. Enhanced surveillance will be necessary post-elimination, however, given the reintroduction risk from long-distance dog movements.
Visualization of a variety of possible dosimetric outcomes in radiation therapy using dose-volume histogram bands.

PubMed

Trofimov, Alexei; Unkelbach, Jan; DeLaney, Thomas F; Bortfeld, Thomas

2012-01-01

Dose-volume histograms (DVH) are the most common tool used in the appraisal of the quality of a clinical treatment plan. However, when delivery uncertainties are present, the DVH may not always accurately describe the dose distribution actually delivered to the patient. We present a method, based on DVH formalism, to visualize the variability in the expected dosimetric outcome of a treatment plan. For a case of chordoma of the cervical spine, we compared 2 intensity modulated proton therapy plans. Treatment plan A was optimized based on dosimetric objectives alone (ie, desired target coverage, normal tissue tolerance). Plan B was created employing a published probabilistic optimization method that considered the uncertainties in patient setup and proton range in tissue. Dose distributions and DVH for both plans were calculated for the nominal delivery scenario, as well as for scenarios representing deviations from the nominal setup, and a systematic error in the estimate of range in tissue. The histograms from various scenarios were combined to create DVH bands to illustrate possible deviations from the nominal plan for the expected magnitude of setup and range errors. In the nominal scenario, the DVH from plan A showed superior dose coverage, higher dose homogeneity within the target, and improved sparing of the adjacent critical structure. However, when the dose distributions and DVH from plans A and B were recalculated for different error scenarios (eg, proton range underestimation by 3 mm), the plan quality, reflected by DVH, deteriorated significantly for plan A, while plan B was only minimally affected. In the DVH-band representation, plan A produced wider bands, reflecting its higher vulnerability to delivery errors, and uncertainty in the dosimetric outcome. The results illustrate that comparison of DVH for the nominal scenario alone does not provide any information about the relative sensitivity of dosimetric outcome to delivery uncertainties. Thus, such comparison may be misleading and may result in the selection of an inferior plan for delivery to a patient. A better-informed decision can be made if additional information about possible dosimetric variability is presented; for example, in the form of DVH bands. Copyright © 2012 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

Essential health care among Mexican indigenous people in a universal coverage context.

PubMed

Servan-Mori, Edson; Pelcastre-Villafuerte, Blanca; Heredia-Pi, Ileana; Montoya-Rodríguez, Arain

2014-01-01

To analyze the influence of indigenous condition on essential health care among Mexican children, older people and women in reproductive age. The influence of indigenous condition on the probability of receiving medical care due to acute respiratory infection (ARI) and acute diarrheal disease (ADD), vaccination coverage; and antenatal care (ANC) was analyzed using the 2012 National Health Survey and non-experimental matching methods. Indigenous condition does not influence per-se vaccination coverage (in < 1 year), probability of attention of ARI's and ADD's as well as, timely, frequent, and quality ANC. Being indigenous and older adult increases 9% the probability of receiving a fulfilled vaccination schedule. Unfavorable structural conditions in which Mexican indigenous live constitutes the persistent mechanisms of their health vulnerability. Public policy should consider this level of intervention, in a way that intensive and focalized health strategies contribute to improve their health condition and life.
Estimation of the biserial correlation and its sampling variance for use in meta-analysis.

PubMed

Jacobs, Perke; Viechtbauer, Wolfgang

2017-06-01

Meta-analyses are often used to synthesize the findings of studies examining the correlational relationship between two continuous variables. When only dichotomous measurements are available for one of the two variables, the biserial correlation coefficient can be used to estimate the product-moment correlation between the two underlying continuous variables. Unlike the point-biserial correlation coefficient, biserial correlation coefficients can therefore be integrated with product-moment correlation coefficients in the same meta-analysis. The present article describes the estimation of the biserial correlation coefficient for meta-analytic purposes and reports simulation results comparing different methods for estimating the coefficient's sampling variance. The findings indicate that commonly employed methods yield inconsistent estimates of the sampling variance across a broad range of research situations. In contrast, consistent estimates can be obtained using two methods that appear to be unknown in the meta-analytic literature. A variance-stabilizing transformation for the biserial correlation coefficient is described that allows for the construction of confidence intervals for individual coefficients with close to nominal coverage probabilities in most of the examined conditions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Prediction of Low Community Sanitation Coverage Using Environmental and Sociodemographic Factors in Amhara Region, Ethiopia

PubMed Central

Oswald, William E.; Stewart, Aisha E. P.; Flanders, W. Dana; Kramer, Michael R.; Endeshaw, Tekola; Zerihun, Mulat; Melaku, Birhanu; Sata, Eshetu; Gessesse, Demelash; Teferi, Tesfaye; Tadesse, Zerihun; Guadie, Birhan; King, Jonathan D.; Emerson, Paul M.; Callahan, Elizabeth K.; Moe, Christine L.; Clasen, Thomas F.

2016-01-01

This study developed and validated a model for predicting the probability that communities in Amhara Region, Ethiopia, have low sanitation coverage, based on environmental and sociodemographic conditions. Community sanitation coverage was measured between 2011 and 2014 through trachoma control program evaluation surveys. Information on environmental and sociodemographic conditions was obtained from available data sources and linked with community data using a geographic information system. Logistic regression was used to identify predictors of low community sanitation coverage (< 20% versus ≥ 20%). The selected model was geographically and temporally validated. Model-predicted probabilities of low community sanitation coverage were mapped. Among 1,502 communities, 344 (22.90%) had coverage below 20%. The selected model included measures for high topsoil gravel content, an indicator for low-lying land, population density, altitude, and rainfall and had reasonable predictive discrimination (area under the curve = 0.75, 95% confidence interval = 0.72, 0.78). Measures of soil stability were strongly associated with low community sanitation coverage, controlling for community wealth, and other factors. A model using available environmental and sociodemographic data predicted low community sanitation coverage for areas across Amhara Region with fair discrimination. This approach could assist sanitation programs and trachoma control programs, scaling up or in hyperendemic areas, to target vulnerable areas with additional activities or alternate technologies. PMID:27430547
Global Precipitation Measurement - Report 9 Core Coverage Trade Space Analysis

NASA Technical Reports Server (NTRS)

Mailhe, Laurie; Schiff, Conrad; Mendelsohn, Chad; Everett, David; Folta, David

2002-01-01

This paper summarizes the GPM-Core coverage trade space analysis. The goal of this analysis was to determine the GPM-Core sensitivity to changes in altitude and inclination for the three onboard instruments: the radiometer, the KU band radar and the KA band radar. This study will enable a better choice of the nominal GPM-Core orbit as well as the optimal size of the maintenance box (+/-1 km, +/-5 km..). For this work, we used two different figures-of-merit: (1) the time required to cover 100% of the +/-65 deg latitude band and (2) the coverage obtained for a given propagation time (7 days and 30 days). The first figure-of-merit is used for the radiometer as it has a sensor cone half-angle between 3 to 5 times bigger than the radars. Thus, we anticipate that for this instrument the period of the orbit (i.e. altitude) will be the main driver and that the 100% coverage value will be reached within less than a week. The second figure-of-merit is used for the radar instruments as they have small sensor cone half-angle and will, in some cases, never reach the 100% coverage threshold point.
The effect of health-facility admission and skilled birth attendant coverage on maternal survival in India: a case-control analysis.

PubMed

Montgomery, Ann L; Fadel, Shaza; Kumar, Rajesh; Bondy, Sue; Moineddin, Rahim; Jha, Prabhat

2014-01-01

Research in areas of low skilled attendant coverage found that maternal mortality is paradoxically higher in women who seek obstetric care. We estimated the effect of health-facility admission on maternal survival, and how this effect varies with skilled attendant coverage across India. Using unmatched population-based case-control analysis of national datasets, we compared the effect of health-facility admission at any time (antenatal, intrapartum, postpartum) on maternal deaths (cases) to women reporting pregnancies (controls). Probability of maternal death decreased with increasing skilled attendant coverage, among both women who were and were not admitted to a health-facility, however, the risk of death among women who were admitted was higher (at 50% coverage, OR = 2.32, 95% confidence interval 1.85-2.92) than among those women who were not; while at higher levels of coverage, the effect of health-facility admission was attenuated. In a secondary analysis, the probability of maternal death decreased with increasing coverage among both women admitted for delivery or delivered at home but there was no effect of admission for delivery on mortality risk (50% coverage, OR = 1.0, 0.80-1.25), suggesting that poor quality of obstetric care may have attenuated the benefits of facility-based care. Subpopulation analysis of obstetric hemorrhage cases and report of 'excessive bleeding' in controls showed that the probability of maternal death decreased with increasing skilled attendant coverage; but the effect of health-facility admission was attenuated (at 50% coverage, OR = 1.47, 0.95-1.79), suggesting that some of the effect in the main model can be explained by women arriving at facility with complications underway. Finally, highest risk associated with health-facility admission was clustered in women with education ≤ 8 years. The effect of health-facility admission did vary by skilled attendant coverage, and this effect appears to be driven partially by reverse causality; however, inequitable access to and possibly poor quality of healthcare for primary and emergency services appears to play a role in maternal survival as well.
Variation in Empiric Coverage Versus Detection of Methicillin-Resistant Staphylococcus aureus and Pseudomonas aeruginosa in Hospitalizations for Community-Onset Pneumonia Across 128 US Veterans Affairs Medical Centers.

PubMed

Jones, Barbara E; Brown, Kevin Antoine; Jones, Makoto M; Huttner, Benedikt D; Greene, Tom; Sauer, Brian C; Madaras-Kelly, Karl; Rubin, Michael A; Bidwell Goetz, Matthew; Samore, Matthew H

2017-08-01

OBJECTIVE To examine variation in antibiotic coverage and detection of resistant pathogens in community-onset pneumonia. DESIGN Cross-sectional study. SETTING A total of 128 hospitals in the Veterans Affairs health system. PARTICIPANTS Hospitalizations with a principal diagnosis of pneumonia from 2009 through 2010. METHODS We examined proportions of hospitalizations with empiric antibiotic coverage for methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PAER) and with initial detection in blood or respiratory cultures. We compared lowest- versus highest-decile hospitals, and we estimated adjusted probabilities (AP) for patient- and hospital-level factors predicting coverage and detection using hierarchical regression modeling. RESULTS Among 38,473 hospitalizations, empiric coverage varied widely across hospitals (MRSA lowest vs highest, 8.2% vs 42.0%; PAER lowest vs highest, 13.9% vs 44.4%). Detection rates also varied (MRSA lowest vs highest, 0.5% vs 3.6%; PAER lowest vs highest, 0.6% vs 3.7%). Whereas coverage was greatest among patients with recent hospitalizations (AP for anti-MRSA, 54%; AP for anti-PAER, 59%) and long-term care (AP for anti-MRSA, 60%; AP for anti-PAER, 66%), detection was greatest in patients with a previous history of a positive culture (AP for MRSA, 7.9%; AP for PAER, 11.9%) and in hospitals with a high prevalence of the organism in pneumonia (AP for MRSA, 3.9%; AP for PAER, 3.2%). Low hospital complexity and rural setting were strong negative predictors of coverage but not of detection. CONCLUSIONS Hospitals demonstrated widespread variation in both coverage and detection of MRSA and PAER, but probability of coverage correlated poorly with probability of detection. Factors associated with empiric coverage (eg, healthcare exposure) were different from those associated with detection (eg, microbiology history). Providing microbiology data during empiric antibiotic decision making could better align coverage to risk for resistant pathogens and could promote more judicious use of broad-spectrum antibiotics. Infect Control Hosp Epidemiol 2017;38:937-944.
Assessment of Group Preferences and Group Uncertainty for Decision Making

DTIC Science & Technology

1976-06-01

the individ- uals. decision making , group judgments should be preferred to individual judgments if obtaining group judgments costs more. -26- -YI IV... decision making group . IV. A. 3. Aggregation using conjugate distribution. Arvther procedure for combining indivi(jai probability judgments into a group...statisticized group group decision making group judgment subjective probability Delphi method expected utility nominal group 20. ABSTRACT (Continue on
Comparison of Ordinal and Nominal Classification Trees to Predict Ordinal Expert-Based Occupational Exposure Estimates in a Case–Control Study

PubMed Central

Wheeler, David C.; Archer, Kellie J.; Burstyn, Igor; Yu, Kai; Stewart, Patricia A.; Colt, Joanne S.; Baris, Dalsu; Karagas, Margaret R.; Schwenn, Molly; Johnson, Alison; Armenti, Karla; Silverman, Debra T.; Friesen, Melissa C.

2015-01-01

Objectives: To evaluate occupational exposures in case–control studies, exposure assessors typically review each job individually to assign exposure estimates. This process lacks transparency and does not provide a mechanism for recreating the decision rules in other studies. In our previous work, nominal (unordered categorical) classification trees (CTs) generally successfully predicted expert-assessed ordinal exposure estimates (i.e. none, low, medium, high) derived from occupational questionnaire responses, but room for improvement remained. Our objective was to determine if using recently developed ordinal CTs would improve the performance of nominal trees in predicting ordinal occupational diesel exhaust exposure estimates in a case–control study. Methods: We used one nominal and four ordinal CT methods to predict expert-assessed probability, intensity, and frequency estimates of occupational diesel exhaust exposure (each categorized as none, low, medium, or high) derived from questionnaire responses for the 14983 jobs in the New England Bladder Cancer Study. To replicate the common use of a single tree, we applied each method to a single sample of 70% of the jobs, using 15% to test and 15% to validate each method. To characterize variability in performance, we conducted a resampling analysis that repeated the sample draws 100 times. We evaluated agreement between the tree predictions and expert estimates using Somers’ d, which measures differences in terms of ordinal association between predicted and observed scores and can be interpreted similarly to a correlation coefficient. Results: From the resampling analysis, compared with the nominal tree, an ordinal CT method that used a quadratic misclassification function and controlled tree size based on total misclassification cost had a slightly better predictive performance that was statistically significant for the frequency metric (Somers’ d: nominal tree = 0.61; ordinal tree = 0.63) and similar performance for the probability (nominal = 0.65; ordinal = 0.66) and intensity (nominal = 0.65; ordinal = 0.65) metrics. The best ordinal CT predicted fewer cases of large disagreement with the expert assessments (i.e. no exposure predicted for a job with high exposure and vice versa) compared with the nominal tree across all of the exposure metrics. For example, the percent of jobs with expert-assigned high intensity of exposure that the model predicted as no exposure was 29% for the nominal tree and 22% for the best ordinal tree. Conclusions: The overall agreements were similar across CT models; however, the use of ordinal models reduced the magnitude of the discrepancy when disagreements occurred. As the best performing model can vary by situation, researchers should consider evaluating multiple CT methods to maximize the predictive performance within their data. PMID:25433003
TU-AB-BRB-01: Coverage Evaluation and Probabilistic Treatment Planning as a Margin Alternative

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siebers, J.

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To understand robust-planning as a clinical alternative to using margin-based planning. To understand conceptual differences between uncertainty and predictable motion. To understand fundamental limitations of the PTV concept that probabilistic planning can overcome. To understand the major contributing factors to target and normal tissue coverage probability. To understand the similarities and differences of various robust planning techniques To understand the benefits and limitations of robust planning techniques.« less
TU-AB-BRB-03: Coverage-Based Treatment Planning to Accommodate Organ Deformable Motions and Contouring Uncertainties for Prostate Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, H.

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To understand robust-planning as a clinical alternative to using margin-based planning. To understand conceptual differences between uncertainty and predictable motion. To understand fundamental limitations of the PTV concept that probabilistic planning can overcome. To understand the major contributing factors to target and normal tissue coverage probability. To understand the similarities and differences of various robust planning techniques To understand the benefits and limitations of robust planning techniques.« less
TU-AB-BRB-00: New Methods to Ensure Target Coverage

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2015-06-15

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To understand robust-planning as a clinical alternative to using margin-based planning. To understand conceptual differences between uncertainty and predictable motion. To understand fundamental limitations of the PTV concept that probabilistic planning can overcome. To understand the major contributing factors to target and normal tissue coverage probability. To understand the similarities and differences of various robust planning techniques To understand the benefits and limitations of robust planning techniques.« less
Quantitative imaging biomarkers: Effect of sample size and bias on confidence interval coverage.

PubMed

Obuchowski, Nancy A; Bullen, Jennifer

2017-01-01

Introduction Quantitative imaging biomarkers (QIBs) are being increasingly used in medical practice and clinical trials. An essential first step in the adoption of a quantitative imaging biomarker is the characterization of its technical performance, i.e. precision and bias, through one or more performance studies. Then, given the technical performance, a confidence interval for a new patient's true biomarker value can be constructed. Estimating bias and precision can be problematic because rarely are both estimated in the same study, precision studies are usually quite small, and bias cannot be measured when there is no reference standard. Methods A Monte Carlo simulation study was conducted to assess factors affecting nominal coverage of confidence intervals for a new patient's quantitative imaging biomarker measurement and for change in the quantitative imaging biomarker over time. Factors considered include sample size for estimating bias and precision, effect of fixed and non-proportional bias, clustered data, and absence of a reference standard. Results Technical performance studies of a quantitative imaging biomarker should include at least 35 test-retest subjects to estimate precision and 65 cases to estimate bias. Confidence intervals for a new patient's quantitative imaging biomarker measurement constructed under the no-bias assumption provide nominal coverage as long as the fixed bias is <12%. For confidence intervals of the true change over time, linearity must hold and the slope of the regression of the measurements vs. true values should be between 0.95 and 1.05. The regression slope can be assessed adequately as long as fixed multiples of the measurand can be generated. Even small non-proportional bias greatly reduces confidence interval coverage. Multiple lesions in the same subject can be treated as independent when estimating precision. Conclusion Technical performance studies of quantitative imaging biomarkers require moderate sample sizes in order to provide robust estimates of bias and precision for constructing confidence intervals for new patients. Assumptions of linearity and non-proportional bias should be assessed thoroughly.
Does Retiree Health Insurance Encourage Early Retirement?*

PubMed Central

Nyce, Steven; Schieber, Sylvester J.; Shoven, John B.; Slavov, Sita Nataraj; Wise, David A.

2013-01-01

The strong link between health insurance and employment in the United States may cause workers to delay retirement until they become eligible for Medicare at age 65. However, some employers extend health insurance benefits to their retirees, and individuals who are eligible for such retiree health benefits need not wait until age 65 to retire with group health coverage. We investigate the impact of retiree health insurance on early retirement using employee-level data from 54 diverse firms that are clients of Towers Watson, a leading benefits consulting firm. We find that retiree health coverage has its strongest effects at ages 62 through 64. Coverage that includes an employer contribution is associated with a 6.3 percentage point (36.2 percent) increase in the probability of turnover at age 62, a 7.7 percentage point (48.8 percent) increase in the probability of turnover at age 63, and a 5.5 percentage point (38.0 percent) increase in the probability of turnover at age 64. Conditional on working at age 57, such coverage reduces the expected retirement age by almost three months and reduces the total number of person-years worked between ages 58 and 64 by 5.6 percent. PMID:24039312
The role of retiree health insurance in the early retirement of public sector employees.

PubMed

Shoven, John B; Slavov, Sita Nataraj

2014-12-01

Most government employees have access to retiree health coverage, which provides them with group health coverage even if they retire before Medicare eligibility. We study the impact of retiree health coverage on the labor supply of public sector workers between the ages of 55 and 64. We find that retiree health coverage raises the probability of stopping full time work by 4.3 percentage points (around 38 percent) over two years among public sector workers aged 55-59, and by 6.7 percentage points (around 26 percent) over two years among public sector workers aged 60-64. In the younger age group, retiree health insurance mostly seems to facilitate transitions to part-time work rather than full retirement. However, in the older age group, it increases the probability of stopping work entirely by 4.3 percentage points (around 22 percent). Copyright © 2014 Elsevier B.V. All rights reserved.
Prescription drug coverage and effects on drug expenditures among elderly Medicare beneficiaries.

PubMed

Huh, Soonim; Rice, Thomas; Ettner, Susan L

2008-06-01

To identify determinants of drug coverage among elderly Medicare beneficiaries and to investigate the impact of drug coverage on drug expenditures with and without taking selection bias into account. The primary data were from the 2000 Medicare Current Beneficiary Survey (MCBS) Cost and Use file, linked to other data sources at the county or state-level that provided instrumental variables. Community-dwelling elderly Medicare beneficiaries who completed the survey were included in the study (N=7,525). A probit regression to predict the probability of having drug coverage and the effects of drug coverage on drug expenditures was estimated by a two-part model, assuming no correlation across equations. In addition, the discrete factor model estimated choice of drug coverage and expenditures for prescription drugs simultaneously to control for self-selection into drug coverage, allowing for correlation of error terms across equations. Findings indicated that unobservable characteristics leading elderly Medicare beneficiaries to purchase drug coverage also lead them to have higher drug expenditures on conditional use (i.e., adverse selection), while the same unobservable factors do not influence their decisions whether to use any drugs. After controlling for potential selection bias, the probability of any drug use among persons with drug coverage use was 4.5 percent higher than among those without, and drug coverage led to an increase in drug expenditures of $308 among those who used prescription drugs. Given significant adverse selection into drug coverage before the implementation of the Medicare Prescription Drug Improvement and Modernization Act, it is essential that selection effects be monitored as beneficiaries choose whether or not to enroll in this voluntary program.
Estimate of Probability of Crack Detection from Service Difficulty Report Data.

DOT National Transportation Integrated Search

1995-09-01

The initiation and growth of cracks in a fuselage lap joint were simulated. Stochastic distribution of crack initiation and rivet interference were included. The simulation also contained a simplified crack growth. Nominal crack growth behavior of la...
Estimate of probability of crack detection from service difficulty report data

DOT National Transportation Integrated Search

1994-09-01

The initiation and growth of cracks in a fuselage lap joint were simulated. Stochastic distribution of crack initiation and rivet interference were included. The simulation also contained a simplified crack growth. Nominal crack growth behavior of la...
Estimating Premium Sensitivity for Children's Public Health Insurance Coverage: Selection but No Death Spiral

PubMed Central

Marton, James; Ketsche, Patricia G; Snyder, Angela; Adams, E Kathleen; Zhou, Mei

2015-01-01

Objective To estimate the effect of premium increases on the probability that near-poor and moderate-income children disenroll from public coverage. Data Sources Enrollment, eligibility, and claims data for Georgia's PeachCare for Kids™ (CHIP) program for multiple years. Study Design We exploited policy-induced variation in premiums generated by cross-sectional differences and changes over time in enrollee age, family size, and income to estimate the duration of enrollment as a function of the effective (per child) premium. We classify children as being of low, medium, or high illness severity. Principal Findings A dollar increase in the per-child premium is associated with a slight increase in a typical child's monthly probability of exiting coverage from 7.70 to 7.83 percent. Children with low illness severity have a significantly higher monthly baseline probability of exiting than children with medium or high illness severity, but the enrollment response to premium increases is similar across all three groups. Conclusions Success in achieving coverage gains through public programs is tempered by persistent problems in maintaining enrollment, which is modestly affected by premium increases. Retention is subject to adverse selection problems, but premium increases do not appear to significantly magnify the selection problem in this case. PMID:25130764
Theoretical studies of positron states and annihilation characteristics at the oxidized Cu(100) surface

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Weiss, A. H.

2013-04-01

In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. An ab-initio study of the electronic properties of the Cu(100) missing row reconstructed surface at various on surface and sub-surface oxygen coverages has been performed on the basis of the density functional theory (DFT) using the Dmol3 code and the generalized gradient approximation (GGA). Surface structures in calculations have been constructed by adding oxygen atoms to various surface hollow and sub-surface octahedral sites of the 0.5 monolayer (ML) missing row reconstructed phase of the Cu(100) surface with oxygen coverages ranging from 0.5 to 1.5 ML. The charge redistribution at the surface and variations in atomic structure and chemical composition of the topmost layers associated with oxidation and surface reconstruction have been found to affect the spatial extent and localization of the positron surface state wave function and annihilation probabilities of surface trapped positrons with relevant core electrons. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES). It has been shown that positron annihilation probabilities with Cu 3s and 3p core electrons decrease when total (on-surface and sub-surface) oxygen coverage of the Cu(100) surface increases up to 1 ML. The calculations show that for high oxygen coverage when total oxygen coverage is 1. 5 ML the positron is not bound to the surface.
Theoretical studies of positron states and annihilation characteristics at the oxidized Cu(100) surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fazleev, N. G.; Weiss, A. H.

2013-04-19

In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. An ab-initio study of the electronic properties of the Cu(100) missing row reconstructed surface at various on surface and sub-surface oxygen coverages has been performed on the basis of the density functional theory (DFT) using the Dmol3 code and the generalized gradient approximation (GGA). Surface structures in calculations have been constructed by adding oxygen atoms to various surface hollow and sub-surface octahedral sitesmore » of the 0.5 monolayer (ML) missing row reconstructed phase of the Cu(100) surface with oxygen coverages ranging from 0.5 to 1.5 ML. The charge redistribution at the surface and variations in atomic structure and chemical composition of the topmost layers associated with oxidation and surface reconstruction have been found to affect the spatial extent and localization of the positron surface state wave function and annihilation probabilities of surface trapped positrons with relevant core electrons. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES). It has been shown that positron annihilation probabilities with Cu 3s and 3p core electrons decrease when total (on-surface and sub-surface) oxygen coverage of the Cu(100) surface increases up to 1 ML. The calculations show that for high oxygen coverage when total oxygen coverage is 1. 5 ML the positron is not bound to the surface.« less

A study of actions in operative notes.

PubMed

Wang, Yan; Pakhomov, Serguei; Burkart, Nora E; Ryan, James O; Melton, Genevieve B

2012-01-01

Operative notes contain rich information about techniques, instruments, and materials used in procedures. To assist development of effective information extraction (IE) techniques for operative notes, we investigated the sublanguage used to describe actions within the operative report 'procedure description' section. Deep parsing results of 362,310 operative notes with an expanded Stanford parser using the SPECIALIST Lexicon resulted in 200 verbs (92% coverage) including 147 action verbs. Nominal action predicates for each action verb were gathered from WordNet, SPECIALIST Lexicon, New Oxford American Dictionary and Stedman's Medical Dictionary. Coverage gaps were seen in existing lexical, domain, and semantic resources (Unified Medical Language System (UMLS) Metathesaurus, SPECIALIST Lexicon, WordNet and FrameNet). Our findings demonstrate the need to construct surgical domain-specific semantic resources for IE from operative notes.
Air and Space Power Journal. Volume 24, Number 4, Winter 2010

DTIC Science & Technology

2010-01-01

assessment of damage. In addition to still photos, Predator RPAs collected full-motion video during around- the-clock coverage of select areas in...Dissemination of the video col- lected by the Predators to a variety of users, both on the ground in Haiti and at locations outside the area of...links, and full-motion- video capability.29 The aircraft must operate from austere forward locations and provide a nominal five-hour endurance with a
Quantifying Uncertainty in Early Lifecycle Cost Estimation (QUELCE)

DTIC Science & Technology

2011-12-01

state, and use their best judgment on the probability that the nominal state will change as shown in Table 3. CMU/SEI-2011-TR-026 | 17 Each cell ...Figure 6. The row is the program change driver and the column is the effect. For example, if the cell is designated (Advo- cacy, Funding), then the... cell will contain the conditional probability that an Advocacy change will cause a Funding change. The diagonal will be blank. We then populate the
The nominal cooling tower

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burger, R.

1995-12-31

The heat Rejection Industry defines a nominal cooling tower as circulating three gallons of water per minute (GPM) per ton of refrigeration from entering the tower at 95{degrees}F. Hot Water temperature (HWT) Leaving at 85{degrees}F Cold Water Temperature (CWT) at a Design Wet Bulb of 70{degrees}F (WBT). Manufacturers then provide a selection chart based on various wet bulb temperatures and HWTs. The wet bulb fluctuates and varies through out the world since it is the combination ambient temperature, relative humidity, and/or dew point. Different HWT and CWT requirements are usually charted as they change, so that the user can selectmore » the nominal cooling tower model recommended by the manufacturer. Ask any HVAC operator, refinery manager, power generating station operator what happens when the Wet Bulb reaches or exceeds the design WBT of the area. He probably will tell you, {open_quotes}My cooling tower works quite well, but in the summer time, I usually have trouble with it.{close_quotes} This occurs because he is operating a nominal cooling tower.« less
Temporal Associations of Popularity and Alcohol Use Among Middle School Students

PubMed Central

Tucker, Joan S.; Miles, Jeremy N. V.; D’Amico, Elizabeth J.; Zhou, Annie J.; Green, Harold D.; Shih, Regina A.

2012-01-01

Purpose The goal of this study is to better understand the longitudinal cross-lagged associations between popularity, assessed through self-rating and peer nominations, and alcohol use among middle school students. Methods The analytic sample is 1,835 6th–8th grade students who were initially recruited from three California middle schools and surveyed in the fall and spring semesters of two academic years. Students reported on their background characteristics, past month alcohol use, and perceived popularity. Additionally, students provided school-based friendship nominations, which were used to calculate peer-nominated popularity. A cross-lagged regression approach within a structural equation modeling framework was used to examine the longitudinal relationship between popularity (self-rated and peer-nominated) and alcohol use. Results There was a statistically significant (p = 0.024) association between peer-nominated popularity and the probability of alcohol consumption at the subsequent survey, but not vice versa. Our results suggest that in a scenario where 8% of students are past month drinkers, each increase of 5 friendship nominations is associated with a 30% greater risk of being a current drinker at the next wave. We found no evidence of longitudinal associations between past month alcohol consumption and self-rated popularity. Conclusions Popularity is a risk factor for drinking during the middle school years, with peer-nominated popularity being more predictive of use than self-perceptions of popularity. To inform alcohol prevention efforts for middle school students, additional research is needed to better understand why adolescents with a larger number of school-based friendship ties are more inclined to drink. PMID:23260843
TU-AB-BRB-02: Stochastic Programming Methods for Handling Uncertainty and Motion in IMRT Planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unkelbach, J.

The accepted clinical method to accommodate targeting uncertainties inherent in fractionated external beam radiation therapy is to utilize GTV-to-CTV and CTV-to-PTV margins during the planning process to design a PTV-conformal static dose distribution on the planning image set. Ideally, margins are selected to ensure a high (e.g. >95%) target coverage probability (CP) in spite of inherent inter- and intra-fractional positional variations, tissue motions, and initial contouring uncertainties. Robust optimization techniques, also known as probabilistic treatment planning techniques, explicitly incorporate the dosimetric consequences of targeting uncertainties by including CP evaluation into the planning optimization process along with coverage-based planning objectives. Themore » treatment planner no longer needs to use PTV and/or PRV margins; instead robust optimization utilizes probability distributions of the underlying uncertainties in conjunction with CP-evaluation for the underlying CTVs and OARs to design an optimal treated volume. This symposium will describe CP-evaluation methods as well as various robust planning techniques including use of probability-weighted dose distributions, probability-weighted objective functions, and coverage optimized planning. Methods to compute and display the effect of uncertainties on dose distributions will be presented. The use of robust planning to accommodate inter-fractional setup uncertainties, organ deformation, and contouring uncertainties will be examined as will its use to accommodate intra-fractional organ motion. Clinical examples will be used to inter-compare robust and margin-based planning, highlighting advantages of robust-plans in terms of target and normal tissue coverage. Robust-planning limitations as uncertainties approach zero and as the number of treatment fractions becomes small will be presented, as well as the factors limiting clinical implementation of robust planning. Learning Objectives: To understand robust-planning as a clinical alternative to using margin-based planning. To understand conceptual differences between uncertainty and predictable motion. To understand fundamental limitations of the PTV concept that probabilistic planning can overcome. To understand the major contributing factors to target and normal tissue coverage probability. To understand the similarities and differences of various robust planning techniques To understand the benefits and limitations of robust planning techniques.« less
Mental Health and Social Networks After Disaster.

PubMed

Bryant, Richard A; Gallagher, H Colin; Gibbs, Lisa; Pattison, Philippa; MacDougall, Colin; Harms, Louise; Block, Karen; Baker, Elyse; Sinnott, Vikki; Ireton, Greg; Richardson, John; Forbes, David; Lusher, Dean

2017-03-01

Although disasters are a major cause of mental health problems and typically affect large numbers of people and communities, little is known about how social structures affect mental health after a disaster. The authors assessed the extent to which mental health outcomes after disaster are associated with social network structures. In a community-based cohort study of survivors of a major bushfire disaster, participants (N=558) were assessed for probable posttraumatic stress disorder (PTSD) and probable depression. Social networks were assessed by asking participants to nominate people with whom they felt personally close. These nominations were used to construct a social network map that showed each participant's ties to other participants they nominated and also to other participants who nominated them. This map was then analyzed for prevailing patterns of mental health outcomes. Depression risk was higher for participants who reported fewer social connections, were connected to other depressed people, or were connected to people who had left their community. PTSD risk was higher if fewer people reported being connected with the participant, if those who felt close to the participant had higher levels of property loss, or if the participant was linked to others who were themselves not interconnected. Interestingly, being connected to other people who in turn were reciprocally close to each other was associated with a lower risk of PTSD. These findings provide the first evidence of disorder-specific patterns in relation to one's social connections after disaster. Depression appears to co-occur in linked individuals, whereas PTSD risk is increased with social fragmentation. These patterns underscore the need to adopt a sociocentric perspective of postdisaster mental health in order to better understand the potential for societal interventions in the wake of disaster.
Optimize the Coverage Probability of Prediction Interval for Anomaly Detection of Sensor-Based Monitoring Series

PubMed Central

Liu, Datong; Peng, Yu; Peng, Xiyuan

2018-01-01

Effective anomaly detection of sensing data is essential for identifying potential system failures. Because they require no prior knowledge or accumulated labels, and provide uncertainty presentation, the probability prediction methods (e.g., Gaussian process regression (GPR) and relevance vector machine (RVM)) are especially adaptable to perform anomaly detection for sensing series. Generally, one key parameter of prediction models is coverage probability (CP), which controls the judging threshold of the testing sample and is generally set to a default value (e.g., 90% or 95%). There are few criteria to determine the optimal CP for anomaly detection. Therefore, this paper designs a graphic indicator of the receiver operating characteristic curve of prediction interval (ROC-PI) based on the definition of the ROC curve which can depict the trade-off between the PI width and PI coverage probability across a series of cut-off points. Furthermore, the Youden index is modified to assess the performance of different CPs, by the minimization of which the optimal CP is derived by the simulated annealing (SA) algorithm. Experiments conducted on two simulation datasets demonstrate the validity of the proposed method. Especially, an actual case study on sensing series from an on-orbit satellite illustrates its significant performance in practical application. PMID:29587372
Joint coverage probability in a simulation study on Continuous-Time Markov Chain parameter estimation.

PubMed

Benoit, Julia S; Chan, Wenyaw; Doody, Rachelle S

2015-01-01

Parameter dependency within data sets in simulation studies is common, especially in models such as Continuous-Time Markov Chains (CTMC). Additionally, the literature lacks a comprehensive examination of estimation performance for the likelihood-based general multi-state CTMC. Among studies attempting to assess the estimation, none have accounted for dependency among parameter estimates. The purpose of this research is twofold: 1) to develop a multivariate approach for assessing accuracy and precision for simulation studies 2) to add to the literature a comprehensive examination of the estimation of a general 3-state CTMC model. Simulation studies are conducted to analyze longitudinal data with a trinomial outcome using a CTMC with and without covariates. Measures of performance including bias, component-wise coverage probabilities, and joint coverage probabilities are calculated. An application is presented using Alzheimer's disease caregiver stress levels. Comparisons of joint and component-wise parameter estimates yield conflicting inferential results in simulations from models with and without covariates. In conclusion, caution should be taken when conducting simulation studies aiming to assess performance and choice of inference should properly reflect the purpose of the simulation.
A New Lunar Globe as Seen by the Moon Mineralogy Mapper: Image Coverage Spectral Dimensionality and Statistical Anomalies

NASA Technical Reports Server (NTRS)

Boardman, J. W.; Pieters, C. M.; Green, R. O.; Clark, R. N.; Sunshine, J.; Combe, J.-P.; Isaacson, P.; Lundeen, S. R.; Malaret, E.; McCord, T.;

2010-01-01

The Moon Mineralogy Mapper (M3), a NASA Discovery Mission of Opportunity, was launched October 22, 2008 from Shriharikota in India on board the Indian ISRO Chandrayaan- 1 spacecraft for a nominal two-year mission in a 100-km polar lunar orbit. M3 is a high-fidelity imaging spectrometer with 260 spectral bands in Target Mode and 85 spectral bands in a reduced-resolution Global Mode. Target Mode pixel sizes are nominally 70 meters and Global pixels (binned 2 by 2) are 140 meters, from the planned 100-km orbit. The mission was cut short, just before halfway, in August, 2009 when the spacecraft ceased operations. Despite the abbreviated mission and numerous technical and scientific challenges during the flight, M3 was able to cover more than 95% of the Moon in Global Mode. These data, presented and analyzed here as a global whole, are revolutionizing our understanding of the Moon. Already, numerous discoveries relating to volatiles and unexpected mineralogy have been published [1], [2], [3]. The rich spectral and spatial information content of the M3 data indicates that many more discoveries and an improved understanding of the mineralogy, geology, photometry, thermal regime and volatile status of our nearest neighbor are forthcoming from these data. Sadly, only minimal high-resolution Target Mode images were acquired, as these were to be the focus of the second half of the mission. This abstract gives the reader a global overview of all the M3 data that were collected and an introduction to their rich spectral character and complexity. We employ a Principal Components statistical method to assess the underlying dimensionality of the Moon as a whole, as seen by M3, and to identify numerous areas that are low-probability targets and thus of potential interest to selenologists.

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 2: Integrated loss of vehicle model

NASA Technical Reports Server (NTRS)

Fragola, Joseph R.; Maggio, Gaspare; Frank, Michael V.; Gerez, Luis; Mcfadden, Richard H.; Collins, Erin P.; Ballesio, Jorge; Appignani, Peter L.; Karns, James J.

1995-01-01

The application of the probabilistic risk assessment methodology to a Space Shuttle environment, particularly to the potential of losing the Shuttle during nominal operation is addressed. The different related concerns are identified and combined to determine overall program risks. A fault tree model is used to allocate system probabilities to the subsystem level. The loss of the vehicle due to failure to contain energetic gas and debris, to maintain proper propulsion and configuration is analyzed, along with the loss due to Orbiter, external tank failure, and landing failure or error.
Influence of Landscape Coverage on Measuring Spatial and Length Properties of Rock Fracture Networks: Insights from Numerical Simulation

NASA Astrophysics Data System (ADS)

Cao, Wenzhuo; Lei, Qinghua

2018-01-01

Natural fractures are ubiquitous in the Earth's crust and often deeply buried in the subsurface. Due to the difficulty in accessing to their three-dimensional structures, the study of fracture network geometry is usually achieved by sampling two-dimensional (2D) exposures at the Earth's surface through outcrop mapping or aerial photograph techniques. However, the measurement results can be considerably affected by the coverage of forests and other plant species over the exposed fracture patterns. We quantitatively study such effects using numerical simulation. We consider the scenario of nominally isotropic natural fracture systems and represent them using 2D discrete fracture network models governed by fractal and length scaling parameters. The groundcover is modelled as random patches superimposing onto the 2D fracture patterns. The effects of localisation and total coverage of landscape patches are further investigated. The fractal dimension and length exponent of the covered fracture networks are measured and compared with those of the original non-covered patterns. The results show that the measured length exponent increases with the reduced localisation and increased coverage of landscape patches, which is more evident for networks dominated by very large fractures (i.e. small underlying length exponent). However, the landscape coverage seems to have a minor impact on the fractal dimension measurement. The research findings of this paper have important implications for field survey and statistical analysis of geological systems.
Subcutaneous interferon β-1a in the treatment of clinically isolated syndromes: 3-year and 5-year results of the phase III dosing frequency-blind multicentre REFLEXION study.

PubMed

Comi, Giancarlo; De Stefano, Nicola; Freedman, Mark S; Barkhof, Frederik; Uitdehaag, Bernard M J; de Vos, Marlieke; Marhardt, Kurt; Chen, Liang; Issard, Delphine; Kappos, Ludwig

2017-04-01

Early treatment following a first clinical demyelinating event (FCDE) delays further disease activity in patients with multiple sclerosis (MS). This study determined the effects of early versus delayed treatment (DT) with subcutaneous interferon (sc IFN) β-1a 44 μg in patients with an FCDE up to 60 months postrandomisation. Patients who completed the 24-month double-blind REFLEX (REbif FLEXible dosing in early MS) study entered an extension (REFLEXION, REbif FLEXible dosing in early MS extensION): patients initially randomised to sc IFN β-1a and not reaching clinically definite MS (clinically definite MS, CDMS (second attack or sustained Expanded Disability Status Scale (EDSS) score increase)) continued original treatment (three times weekly (tiw) or once weekly (qw)); placebo patients switched to tiw (DT); patients with CDMS switched to tiw. Clinical, MRI and adverse event data up to month 60 are reported. 402/517 (77.8%) REFLEX patients entered REFLEXION (DT, n=133; tiw, n=127; qw, n=142). At month 60, cumulative probability of CDMS was: DT 44.6%; qw 40.7% (nominal p=0.084 vs DT); tiw 39.2% (nominal p=0.032 vs DT). Cumulative probability of McDonald MS conversion (CDMS or new MRI activity) at month 60 was also reduced for tiw versus DT (nominal p<0.001). At month 60, mean cumulative numbers of new T2, gadolinium-enhancing and T1 hypointense lesions were lower with sc IFN β-1a qw (nominal p<0.05) and tiw versus DT (nominal p<0.001); T2 and T1 hypointense lesion volume change was lower for sc IFN β-1a tiw versus DT (nominal p<0.01). Treatment was well tolerated; fewer patients receiving tiw versus qw were positive for neutralising or binding antibodies. Over 5 years in patients presenting with an FCDE, early sc IFN β-1a tiw administration versus DT prolonged time to CDMS and McDonald MS, and reduced overall MRI activity. NCT00813709; Results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Temporal associations of popularity and alcohol use among middle school students.

PubMed

Tucker, Joan S; Miles, Jeremy N V; D'Amico, Elizabeth J; Zhou, Annie J; Green, Harold D; Shih, Regina A

2013-01-01

The goal of this study is to better understand the longitudinal cross-lagged associations between popularity, assessed through self-rating and peer nominations, and alcohol use among middle school students. The analytical sample comprises 1,835 sixth- to eighth-grade students who were initially recruited from three California middle schools and surveyed in the fall and spring semesters of 2 academic years. Students reported on their background characteristics, past-month alcohol use, and perceived popularity. Additionally, students provided school-based friendship nominations, which were used to calculate peer-nominated popularity. A cross-lagged regression approach within a structural equation modeling framework was used to examine the longitudinal relationship between popularity (self-rated and peer-nominated) and alcohol use. There was a statistically significant (p = .024) association between peer-nominated popularity and the probability of alcohol consumption at the subsequent survey, but not vice versa. Our results suggest that in a scenario where 8% of students are past-month drinkers, each increase of five friendship nominations is associated with a 30% greater risk of being a current drinker at the next wave. We found no evidence of longitudinal associations between past-month alcohol consumption and self-rated popularity. Popularity is a risk factor for drinking during the middle school years, with peer-nominated popularity being more predictive of use than self-perceptions of popularity. To inform alcohol prevention efforts for middle school students, additional research is needed to better understand why adolescents with a larger number of school-based friendship ties are more inclined to drink. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.
Pinhole induced efficiency variation in perovskite solar cells

NASA Astrophysics Data System (ADS)

Agarwal, Sumanshu; Nair, Pradeep R.

2017-10-01

Process induced efficiency variation is a major concern for all thin film solar cells, including the emerging perovskite based solar cells. In this article, we address the effect of pinholes or process induced surface coverage aspects on the efficiency of such solar cells through detailed numerical simulations. Interestingly, we find that the pinhole size distribution affects the short circuit current and open circuit voltage in contrasting manners. Specifically, while the JS C is heavily dependent on the pinhole size distribution, surprisingly, the VO C seems to be only nominally affected by it. Further, our simulations also indicate that, with appropriate interface engineering, it is indeed possible to design a nanostructured device with efficiencies comparable to those of ideal planar structures. Additionally, we propose a simple technique based on terminal I-V characteristics to estimate the surface coverage in perovskite solar cells.
Funnel plot control limits to identify poorly performing healthcare providers when there is uncertainty in the value of the benchmark.

PubMed

Manktelow, Bradley N; Seaton, Sarah E; Evans, T Alun

2016-12-01

There is an increasing use of statistical methods, such as funnel plots, to identify poorly performing healthcare providers. Funnel plots comprise the construction of control limits around a benchmark and providers with outcomes falling outside the limits are investigated as potential outliers. The benchmark is usually estimated from observed data but uncertainty in this estimate is usually ignored when constructing control limits. In this paper, the use of funnel plots in the presence of uncertainty in the value of the benchmark is reviewed for outcomes from a Binomial distribution. Two methods to derive the control limits are shown: (i) prediction intervals; (ii) tolerance intervals Tolerance intervals formally include the uncertainty in the value of the benchmark while prediction intervals do not. The probability properties of 95% control limits derived using each method were investigated through hypothesised scenarios. Neither prediction intervals nor tolerance intervals produce funnel plot control limits that satisfy the nominal probability characteristics when there is uncertainty in the value of the benchmark. This is not necessarily to say that funnel plots have no role to play in healthcare, but that without the development of intervals satisfying the nominal probability characteristics they must be interpreted with care. © The Author(s) 2014.
SU-E-T-574: Novel Chance-Constrained Optimization in Intensity-Modulated Proton Therapy Planning to Account for Range and Patient Setup Uncertainties

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, Y; Liang, J; Liu, W

2015-06-15

Purpose: We propose to apply a probabilistic framework, namely chanceconstrained optimization, in the intensity-modulated proton therapy (IMPT) planning subject to range and patient setup uncertainties. The purpose is to hedge against the influence of uncertainties and improve robustness of treatment plans. Methods: IMPT plans were generated for a typical prostate patient. Nine dose distributions are computed — the nominal one and one each for ±5mm setup uncertainties along three cardinal axes and for ±3.5% range uncertainty. These nine dose distributions are supplied to the solver CPLEX as chance constraints to explicitly control plan robustness under these representative uncertainty scenarios withmore » certain probability. This probability is determined by the tolerance level. We make the chance-constrained model tractable by converting it to a mixed integer optimization problem. The quality of plans derived from this method is evaluated using dose-volume histogram (DVH) indices such as tumor dose homogeneity (D5% – D95%) and coverage (D95%) and normal tissue sparing like V70 of rectum, V65, and V40 of bladder. We also compare the results from this novel method with the conventional PTV-based method to further demonstrate its effectiveness Results: Our model can yield clinically acceptable plans within 50 seconds. The chance-constrained optimization produces IMPT plans with comparable target coverage, better target dose homogeneity, and better normal tissue sparing compared to the PTV-based optimization [D95% CTV: 67.9 vs 68.7 (Gy), D5% – D95% CTV: 11.9 vs 18 (Gy), V70 rectum: 0.0 % vs 0.33%, V65 bladder: 2.17% vs 9.33%, V40 bladder: 8.83% vs 21.83%]. It also simultaneously makes the plan more robust [Width of DVH band at D50%: 2.0 vs 10.0 (Gy)]. The tolerance level may be varied to control the tradeoff between plan robustness and quality. Conclusion: The chance-constrained optimization generates superior IMPT plan compared to the PTV-based optimization with explicit control of plan robustness. NIH/NCI K25CA168984, Eagles Cancer Research Career Development, The Lawrence W. and Marilyn W. Matteson Fund for Cancer Research, Mayo ASU Seed Grant, and The Kemper Marley Foundation.« less
Examples of measurement uncertainty evaluations in accordance with the revised GUM

NASA Astrophysics Data System (ADS)

Runje, B.; Horvatic, A.; Alar, V.; Medic, S.; Bosnjakovic, A.

2016-11-01

The paper presents examples of the evaluation of uncertainty components in accordance with the current and revised Guide to the expression of uncertainty in measurement (GUM). In accordance with the proposed revision of the GUM a Bayesian approach was conducted for both type A and type B evaluations.The law of propagation of uncertainty (LPU) and the law of propagation of distribution applied through the Monte Carlo method, (MCM) were used to evaluate associated standard uncertainties, expanded uncertainties and coverage intervals. Furthermore, the influence of the non-Gaussian dominant input quantity and asymmetric distribution of the output quantity y on the evaluation of measurement uncertainty was analyzed. In the case when the probabilistically coverage interval is not symmetric, the coverage interval for the probability P is estimated from the experimental probability density function using the Monte Carlo method. Key highlights of the proposed revision of the GUM were analyzed through a set of examples.
Antenatal Care Among Poor Women in Mexico in the Context of Universal Health Coverage.

PubMed

Servan-Mori, Edson; Wirtz, Veronika; Avila-Burgos, Leticia; Heredia-Pi, Ileana

2015-10-01

To study the influence of enrollment in the subsidized insurance program, Seguro Popular (SP), on timely (within three gestational months) and complete (at least four visits) antenatal care, in the context of expanding health coverage in Mexico. A cross-sectional study using data from the National Health and Nutrition Survey 2012 was conducted. Using quasi-experimental matching methods, we analyzed the influence of SP on timely antenatal care and a minimum of four visits for 6175 women (aged 14-49), and explored heterogeneous influences by socioeconomic status (SES) and educational level. Approximately 80 % of women reported timely antenatal care, with no significant difference between SP and non-SP-except among SP women from low SES households, who had an increased probability of timely antenatal care by 1.88 (p < 0.05). Enrollment in SP increased the probability of receiving at least four visits (1.65, p < 0.01) but this was not independently associated with SP enrollment when modeled together with timely antenatal care. Overall, higher SES increased the probability of antenatal care, while higher educational level increased the probability of four visits. To increase the impact of SP on antenatal care requires focusing on efforts to promote timely attendance as an important factor towards achieving the goal of universal health coverage of maternal and child health services in Mexico.
[Influenza vaccination coverage (2011-2014) in healthcare workers from two health departments of the Valencian Community and hospital services more vulnerable to the flu.

PubMed

Tuells, José; García-Román, Vicente; Duro-Torrijos, José Luis

2018-04-05

Health care workers can transmit influenza to patients in health centers, therefore its vaccination is considered a preventive measure first order. The objective of this study was to know the coverage of vaccination against seasonal influenza in health professionals in two health departments of the Valencian Community (Torrevieja and Elx- Crevillent), in the seasons 2011-12, 2012-13 and 2013-14. TA cross-sectional descriptive study was carried out to determine the coverage of influenza vaccination through the Nominal Vaccine Registry (NVR) of the Conselleria de Sanitat de la Generalitat Valenciana. The services with the highest risk of contagion were detected through requests for PCR analysis in patients suspected of influenza during the 2013-14 season. A total of 2035 health professionals were surveyed who achieved an average vaccination coverage of 27.2% in the 2013-14 season, showing an upward trend from the 2011-12 season. Significant differences were observed between professional categories and, practitioners presented the lowest coverage. A total of 192 PCR requests were recorded in both departments. The services which concentrate a greater number of requests were: Internal Medicine (n = 100), urgency service (n = 37), intensive care unit (n = 25) and Pediatrics ( n=154); The influenza vaccination coverage of these services in the 2013-14 seasons was 27.0%, 32.3%, 34.3% and 25.3%, respectively. Although they show an upward trend, vaccination coverage is low in health care personnel. Nurses are the best vaccinated. It would be appropriate to implement immunization strategies aimed specifically at services that, because of their activity, pose a greater risk to the patient.

Regional differences in usage of antenatal care and safe delivery services in Indonesia: findings from a nationally representative survey.

PubMed

Tripathi, Vrijesh; Singh, Rajvir

2017-02-03

Indonesia has shown a nominal increase in antenatal care (ANC) coverage from 93% to 96% in the Indonesia Demographic Health Survey (IDHS)-2012. This is high but for a comprehensive assessment of maternal health coverage in Indonesia, safe delivery services need to be assessed in conjunction with ANC coverage. The study uses survey data from the IDHS-2012 that was conducted among women aged 15-49 years who gave birth during the past 3 years preceding the survey. Socioeconomic and demographic factors affecting ANC coverage and safe delivery services are analysed by segregating the data into 7 regions of Indonesia. Multivariate results show that besides wealth and education differentials, regional differences significantly affect the usage of ANC and safe delivery services across the 7 regions. Univariate analyses show that Sulawesi, Maluku and Western New Guinea islands are at a disadvantage in accessing ANC and safe delivery services. The study recommends that disaggregated regional targets be set in order to further reduce maternal mortality rates in Indonesia. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Medicaid Expansion Under the Affordable Care Act and Insurance Coverage in Rural and Urban Areas.

PubMed

Soni, Aparna; Hendryx, Michael; Simon, Kosali

2017-04-01

To analyze the differential rural-urban impacts of the Affordable Care Act Medicaid expansion on low-income childless adults' health insurance coverage. Using data from the American Community Survey years 2011-2015, we conducted a difference-in-differences regression analysis to test for changes in the probability of low-income childless adults having insurance in states that expanded Medicaid versus states that did not expand, in rural versus urban areas. Analyses employed survey weights, adjusted for covariates, and included a set of falsification tests as well as sensitivity analyses. Medicaid expansion under the Affordable Care Act increased the probability of Medicaid coverage for targeted populations in rural and urban areas, with a significantly greater increase in rural areas (P < .05), but some of these gains were offset by reductions in individual purchased insurance among rural populations (P < .01). Falsification tests showed that the insurance increases were specific to low-income childless adults, as expected, and were largely insignificant for other populations. The Medicaid expansion increased the probability of having "any insurance" for the pooled urban and rural low-income populations, and it specifically increased Medicaid coverage more in rural versus urban populations. There was some evidence that the expansion was accompanied by some shifting from individual purchased insurance to Medicaid in rural areas, and there is a need for future work to understand the implications of this shift on expenditures, access to care and utilization. © 2017 National Rural Health Association.
Sky coverage modeling for the whole sky for laser guide star multiconjugate adaptive optics.

PubMed

Wang, Lianqi; Andersen, David; Ellerbroek, Brent

2012-06-01

The scientific productivity of laser guide star adaptive optics systems strongly depends on the sky coverage, which describes the probability of finding natural guide stars for the tip/tilt wavefront sensor(s) to achieve a certain performance. Knowledge of the sky coverage is also important for astronomers planning their observations. In this paper, we present an efficient method to compute the sky coverage for the laser guide star multiconjugate adaptive optics system, the Narrow Field Infrared Adaptive Optics System (NFIRAOS), being designed for the Thirty Meter Telescope project. We show that NFIRAOS can achieve more than 70% sky coverage over most of the accessible sky with the requirement of 191 nm total rms wavefront.
Transient Region Coverage in the Propulsion IVHM Technology Experiment

NASA Technical Reports Server (NTRS)

Balaban, Edward; Sweet, Adam; Bajwa, Anupa; Maul, William; Fulton, Chris; Chicatelli, amy

2004-01-01

Over the last several years researchers at NASA Glenn and Ames Research Centers have developed a real-time fault detection and isolation system for propulsion subsystems of future space vehicles. The Propulsion IVHM Technology Experiment (PITEX), as it is called follows the model-based diagnostic methodology and employs Livingstone, developed at NASA Ames, as its reasoning engine. The system has been tested on,flight-like hardware through a series of nominal and fault scenarios. These scenarios have been developed using a highly detailed simulation of the X-34 flight demonstrator main propulsion system and include realistic failures involving valves, regulators, microswitches, and sensors. This paper focuses on one of the recent research and development efforts under PITEX - to provide more complete transient region coverage. It describes the development of the transient monitors, the corresponding modeling methodology, and the interface software responsible for coordinating the flow of information between the quantitative monitors and the qualitative, discrete representation Livingstone.
Mars NanoOrbiter: A CubeSat for Mars System Science

NASA Astrophysics Data System (ADS)

Ehlmann, Bethany; Klesh, Andrew; Alsedairy, Talal

2017-10-01

The Mars NanoOrbiter mission consists of two identical 12U spacecraft, launched simultaneously as secondary payloads on a larger planetary mission launch, and deployed to Earth-escape, as early as with Mars 2020. The nominal mission will last for 1 year, during which time the craft will independently navigate to Mars, enter into elliptical orbit, and achieve close flybys of Phobos and Deimos, obtaining unprecedented coverage of each moon. The craft will additionally provide high temporal resolution data of Mars clouds and atmospheric phenomena at multiple times of day. Two spacecraft provide redundancy to reduce the risk in meeting the science objectives at the Mars moons and enhanced coverage of the dynamic Mars atmosphere. This technology is enabled by recent advances in CubeSat propulsion technology, attitude control systems, guidance, navigation and control. NanoOrbiter builds directly on the systems heritage of the MarCO mission, scheduled to launch with the 2018 Discovery mission Insight.
APPLICATION OF A MULTIPURPOSE UNEQUAL-PROBABILITY STREAM SURVEY IN THE MID-ATLANTIC COASTAL PLAIN

EPA Science Inventory

A stratified random sample with unequal-probability selection was used to design a multipurpose survey of headwater streams in the Mid-Atlantic Coastal Plain. Objectives for data from the survey include unbiased estimates of regional stream conditions, and adequate coverage of un...
MAVEN Mapping of Plasma Clouds Near Mars

NASA Astrophysics Data System (ADS)

Hurley, D.; Tran, T.; DiBraccio, G. A.; Espley, J. R.; Soobiah, Y. I. J.

2017-12-01

Brace et al. identified parcels of ionospheric plasma above the nominal ionosphere of Venus, dubbed plasma clouds. These were envisioned as instabilities on the ionopause that evolved to escaping parcels of ionospheric plasma. Mars Global Surveyor (MGS) Electron Reflectometer (ER) also detected signatures of ionospheric plasma above the nominal ionopause of Mars. Initial examination of the MGS ER data suggests that plasma clouds are more prevalent at Mars than at Venus, and similarly exhibit a connection to rotations in the upstream Interplanetary Magnetic Field (IMF) as Zhang et al. showed at Venus. We examine electron data from Mars to determine the locations of plasma clouds in the near-Mars environment using MGS and MAVEN data. The extensive coverage of the MAVEN orbit enables mapping an occurrence rate of the photoelectron spectra in Solar Wind Electron Analyzer (SWEA) data spanning all relevant altitudes and solar zenith angles. Martian plasma clouds are observed near the terminator like at Venus. They move to higher altitude as solar zenith angle increases, consistent with the escaping plasma hypothesis.
Is Welfare Reform Responsible for Low Skilled Women's Declining Health Insurance Coverage in the 1990s?

ERIC Educational Resources Information Center

DeLeire, Thomas; Levine, Judith A.; Levy, Helen

2006-01-01

We use data from the 1989-2001 March Supplements to the Current Population Survey to determine whether welfare reform contributed to declines in health insurance coverage experienced by low-skilled women. Between 1988 and 2000, women with less than a high school education experienced an 8.0 percentage point decline in the probability of having…
A Proposed Approach for Joint Modeling of the Longitudinal and Time-To-Event Data in Heterogeneous Populations: An Application to HIV/AIDS's Disease.

PubMed

Roustaei, Narges; Ayatollahi, Seyyed Mohammad Taghi; Zare, Najaf

2018-01-01

In recent years, the joint models have been widely used for modeling the longitudinal and time-to-event data simultaneously. In this study, we proposed an approach (PA) to study the longitudinal and survival outcomes simultaneously in heterogeneous populations. PA relaxes the assumption of conditional independence (CI). We also compared PA with joint latent class model (JLCM) and separate approach (SA) for various sample sizes (150, 300, and 600) and different association parameters (0, 0.2, and 0.5). The average bias of parameters estimation (AB-PE), average SE of parameters estimation (ASE-PE), and coverage probability of the 95% confidence interval (CP) among the three approaches were compared. In most cases, when the sample sizes increased, AB-PE and ASE-PE decreased for the three approaches, and CP got closer to the nominal level of 0.95. When there was a considerable association, PA in comparison with SA and JLCM performed better in the sense that PA had the smallest AB-PE and ASE-PE for the longitudinal submodel among the three approaches for the small and moderate sample sizes. Moreover, JLCM was desirable for the none-association and the large sample size. Finally, the evaluated approaches were applied on a real HIV/AIDS dataset for validation, and the results were compared.
The demand for preventive and restorative dental services.

PubMed

Meyerhoefer, Chad D; Zuvekas, Samuel H; Manski, Richard

2014-01-01

Chronic tooth decay is the most common chronic condition in the United States among children ages 5-17 and also affects a large percentage of adults. Oral health conditions are preventable, but less than half of the US population uses dental services annually. We seek to examine the extent to which limited dental coverage and high out-of-pocket costs reduce dental service use by the nonelderly privately insured and uninsured. Using data from the 2001-2006 Medical Expenditure Panel Survey and an American Dental Association survey of dental procedure prices, we jointly estimate the probability of using preventive and both basic and major restorative services through a correlated random effects specification that controls for endogeneity. We found that dental coverage increased the probability of preventive care use by 19% and the use of restorative services 11% to 16%. Both conditional and unconditional on dental coverage, the use of dental services was not sensitive to out-of-pocket costs. We conclude that dental coverage is an important determinant of preventive dental service use, but other nonprice factors related to consumer preferences, especially education, are equal if not stronger determinants. Copyright © 2013 John Wiley & Sons, Ltd.
The Effects of Workplace Clean Indoor Air Law Coverage on Workers' Smoking-Related Outcomes.

PubMed

Cheng, Kai-Wen; Liu, Feng; Gonzalez, MariaElena; Glantz, Stanton

2017-02-01

This study investigated the effects of workplace clean indoor air law (CIAL) coverage on worksite compliance with CIALs, smoking participation among indoor workers, and secondhand smoke (SHS) exposure among nonsmoker indoor workers. This study improved on previous research by using the probability of a resident in a county covered by workplace CIALs, taking into account the state, county, and city legislation. The county-level probability of being covered by a CIAL is merged into two large nationally representative US surveys on smoking behaviors: Tobacco Use Supplement of the Current Population Survey (2001-2010) and Behavioral Risk Factor Surveillance System (2000-2006) based on the year of the survey and respondent's geographic location to identify respondents' CIAL coverage. This study estimated several model specifications of including and not including state or county fixed effects, and the effects of workplace CIALs are consistent across models. Increased coverage by workplace CIALs significantly increased likelihood of reporting a complete smoking restriction by 8% and 10% for the two different datasets, decreased smoking participation among indoor workers by 12%, and decreased SHS exposure among nonsmokers by 28%. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
The Effects of Workplace Clean Indoor Air Law Coverage on Workers’ Smoking-Related Outcomes

PubMed Central

Cheng, Kai-Wen; Liu, Feng; Gonzalez, MariaElena; Glantz, Stanton

2015-01-01

This study investigated the effects of workplace clean indoor air law (CIAL) coverage on worksite compliance with CIALs, smoking participation among indoor workers, and secondhand smoke (SHS) exposure among non-smoker indoor workers. This study improved on previous research by using the probability of a resident in a county covered by workplace CIALs taking into account the state, county, and city legislation. The county-level probability of being covered by a CIAL is merged into two large nationally representative US surveys on smoking behaviors: Tobacco Use Supplement of the Current Population Survey (2001–2010) and Behavioral Risk Factor Surveillance System (2000–2006) based on the year of the survey and respondent’s geographic location to identify respondents’ CIAL coverage. This study estimated several model specifications of including and not including state or county fixed effects, and the effects of workplace CIALs are consistent across models. Increased coverage by workplace CIALs significantly increased likelihood of reporting a complete smoking restriction by 8% and 10% for the two different datasets, decreased smoking participation among indoor workers by 12%, and decreased SHS exposure among non-smokers by 28%. PMID:26639369
Health insurance coverage among disabled Medicare enrollees

PubMed Central

Rubin, Jeffrey I.; Wilcox-Gök, Virginia

1991-01-01

In this article, we use the Survey of Income and Program Participation to identify patterns of non-Medicare insurance coverage among disabled Medicare enrollees. Compared with the aged, the disabled are less likely to have private insurance coverage and more likely to have Medicaid. Probit analysis of the determinants of private insurance for disabled Medicare enrollees shows that income, education, marital status, sex, and having an employed family member are positively related to the likelihood of having private health insurance, whereas age and the probability of Medicaid enrollment are negatively related to this likelihood. PMID:10170806
Accounting for imperfect detection of groups and individuals when estimating abundance.

PubMed

Clement, Matthew J; Converse, Sarah J; Royle, J Andrew

2017-09-01

If animals are independently detected during surveys, many methods exist for estimating animal abundance despite detection probabilities <1. Common estimators include double-observer models, distance sampling models and combined double-observer and distance sampling models (known as mark-recapture-distance-sampling models; MRDS). When animals reside in groups, however, the assumption of independent detection is violated. In this case, the standard approach is to account for imperfect detection of groups, while assuming that individuals within groups are detected perfectly. However, this assumption is often unsupported. We introduce an abundance estimator for grouped animals when detection of groups is imperfect and group size may be under-counted, but not over-counted. The estimator combines an MRDS model with an N-mixture model to account for imperfect detection of individuals. The new MRDS-Nmix model requires the same data as an MRDS model (independent detection histories, an estimate of distance to transect, and an estimate of group size), plus a second estimate of group size provided by the second observer. We extend the model to situations in which detection of individuals within groups declines with distance. We simulated 12 data sets and used Bayesian methods to compare the performance of the new MRDS-Nmix model to an MRDS model. Abundance estimates generated by the MRDS-Nmix model exhibited minimal bias and nominal coverage levels. In contrast, MRDS abundance estimates were biased low and exhibited poor coverage. Many species of conservation interest reside in groups and could benefit from an estimator that better accounts for imperfect detection. Furthermore, the ability to relax the assumption of perfect detection of individuals within detected groups may allow surveyors to re-allocate resources toward detection of new groups instead of extensive surveys of known groups. We believe the proposed estimator is feasible because the only additional field data required are a second estimate of group size.
Accounting for imperfect detection of groups and individuals when estimating abundance

USGS Publications Warehouse

Clement, Matthew J.; Converse, Sarah J.; Royle, J. Andrew

2017-01-01

If animals are independently detected during surveys, many methods exist for estimating animal abundance despite detection probabilities <1. Common estimators include double-observer models, distance sampling models and combined double-observer and distance sampling models (known as mark-recapture-distance-sampling models; MRDS). When animals reside in groups, however, the assumption of independent detection is violated. In this case, the standard approach is to account for imperfect detection of groups, while assuming that individuals within groups are detected perfectly. However, this assumption is often unsupported. We introduce an abundance estimator for grouped animals when detection of groups is imperfect and group size may be under-counted, but not over-counted. The estimator combines an MRDS model with an N-mixture model to account for imperfect detection of individuals. The new MRDS-Nmix model requires the same data as an MRDS model (independent detection histories, an estimate of distance to transect, and an estimate of group size), plus a second estimate of group size provided by the second observer. We extend the model to situations in which detection of individuals within groups declines with distance. We simulated 12 data sets and used Bayesian methods to compare the performance of the new MRDS-Nmix model to an MRDS model. Abundance estimates generated by the MRDS-Nmix model exhibited minimal bias and nominal coverage levels. In contrast, MRDS abundance estimates were biased low and exhibited poor coverage. Many species of conservation interest reside in groups and could benefit from an estimator that better accounts for imperfect detection. Furthermore, the ability to relax the assumption of perfect detection of individuals within detected groups may allow surveyors to re-allocate resources toward detection of new groups instead of extensive surveys of known groups. We believe the proposed estimator is feasible because the only additional field data required are a second estimate of group size.
Cost-effectiveness of extending the coverage of water supply fluoridation for the prevention of dental caries in Australia.

PubMed

Cobiac, Linda J; Vos, Theo

2012-08-01

Fluoride was first added to the Australian water supply in 1953, and by 2003, 69% of Australia's population was receiving the minimum recommended dose. Extending coverage of fluoridation to all remaining communities of at least 1000 people is a key strategy of Australia's National Oral Health Plan 2004-2013. We evaluate the cost-effectiveness of this strategy from an Australian health sector perspective. Health gains from the prevention of caries in the Australian population are modelled over the average 15-year lifespan of a treatment plant. Taking capital and on-going operational costs of fluoridation into account, as well as costs of caries treatment, we determine the dollars per disability-adjusted life years (DALY) averted from extending coverage of fluoridation to all large (≥ 1000 people) and small (<1000 people) communities in Australia. Extending coverage of fluoridation to all communities of at least 1000 people will lead to improved population health (3700 DALYs, 95% uncertainty interval: 2200-5700 DALYs), with a dominant cost-effectiveness ratio and 100% probability of cost-savings. Extending coverage to smaller communities leads to 60% more health gains, but is not cost-effective, with a median cost-effectiveness ratio of A$92 000/DALY and only 10% probability of being under a cost-effectiveness threshold of A$50 000/DALY. Extension of fluoridation coverage under the National Oral Health Plan is highly recommended, but given the substantial dental health disparities and inequalities in access to dental care that currently exist for more regional and remote communities, there may be good justification for extending coverage to include all Australians, regardless of where they live, despite less favourable cost-effectiveness. © 2012 John Wiley & Sons A/S.
Fluctuation dynamics of exchange rates on Polish financial market

NASA Astrophysics Data System (ADS)

Orłowski, A.; Struzik, Z. R.; Syczewska, E.; Załuska-Kotur, M. A.

2004-12-01

We show results of local fluctuation analysis, probability distributions, and fractional integration analysis for nominal exchange rates of the Polish zloty versus two foreign currencies (US dollar and German mark/euro). The results confirm the rapid change of the volatility pattern in August 1997. We compare the type of the fluctuation behavior before and after this date.
Medicaid Coverage for Methadone Maintenance and Use of Opioid Agonist Therapy in Specialty Addiction Treatment.

PubMed

Saloner, Brendan; Stoller, Kenneth B; Barry, Colleen L

2016-06-01

This study examined differences in opioid agonist therapy (OAT) utilization among Medicaid-enrolled adults receiving public-sector opioid use disorder treatment in states with Medicaid coverage of methadone maintenance, states with block grant funding only, and states without public coverage of methadone. Person-level treatment admission data, which included information on reason for treatment and use of OAT from 36 states were linked to state-level Medicaid policies collected in a 50-state survey. Probabilities of OAT use among Medicaid enrollees in opioid addiction treatment were calculated, with adjustment for demographic characteristics and patterns of substance use. In adjusted analysis, 45.0% of Medicaid-enrolled individuals in opioid addiction treatment in states with Medicaid coverage for methadone maintenance used OAT, compared with 30.1% in states with block grant coverage only and 17.0% in states with no coverage. Differences were widest in nonintensive outpatient settings. Medicaid methadone maintenance coverage is critical for encouraging OAT among individuals with opioid use disorders.
Analyzing Radio-Frequency Coverage for the ISS

NASA Technical Reports Server (NTRS)

Bolen, Steven M.; Sham, Catherine C.

2007-01-01

The Interactive Coverage Analysis Tool (iCAT) is an interactive desktop computer program serving to (1) support planning of coverage, and management of usage of frequencies, of current and proposed radio communication systems on and near the International Space Station (ISS) and (2) enable definition of requirements for development of future such systems. The iCAT can also be used in design trade studies for other (both outer-space and terrestrial) communication systems. A user can enter the parameters of a communication-system link budget in a table in a worksheet. The nominal (onaxis) link values for the bit-to-noise-energy ratio, received isotropic power (RIP), carrier-to-noise ratio (C/N), power flux density (PFD), and link margin of the system are calculated and displayed in the table. Plots of field gradients for the RIP, C/N, PFD, and link margin are constructed in an ISS coordinate system, at a specified link range, for both the forward and return link parameters, and are displayed in worksheets. The forward and reverse link antenna gain patterns are also constructed and displayed. Line-of-sight (LOS) obstructions can be both incorporated into the gradient plots and displayed on separate plots.
DOE Office of Scientific and Technical Information (OSTI.GOV)

SacconePhD, Scott F; Chesler, Elissa J; Bierut, Laura J

Commercial SNP microarrays now provide comprehensive and affordable coverage of the human genome. However, some diseases have biologically relevant genomic regions that may require additional coverage. Addiction, for example, is thought to be influenced by complex interactions among many relevant genes and pathways. We have assembled a list of 486 biologically relevant genes nominated by a panel of experts on addiction. We then added 424 genes that showed evidence of association with addiction phenotypes through mouse QTL mappings and gene co-expression analysis. We demonstrate that there are a substantial number of SNPs in these genes that are not well representedmore » by commercial SNP platforms. We address this problem by introducing a publicly available SNP database for addiction. The database is annotated using numeric prioritization scores indicating the extent of biological relevance. The scores incorporate a number of factors such as SNP/gene functional properties (including synonymy and promoter regions), data from mouse systems genetics and measures of human/mouse evolutionary conservation. We then used HapMap genotyping data to determine if a SNP is tagged by a commercial microarray through linkage disequilibrium. This combination of biological prioritization scores and LD tagging annotation will enable addiction researchers to supplement commercial SNP microarrays to ensure comprehensive coverage of biologically relevant regions.« less

A Cooperative Search and Coverage Algorithm with Controllable Revisit and Connectivity Maintenance for Multiple Unmanned Aerial Vehicles.

PubMed

Liu, Zhong; Gao, Xiaoguang; Fu, Xiaowei

2018-05-08

In this paper, we mainly study a cooperative search and coverage algorithm for a given bounded rectangle region, which contains several unknown stationary targets, by a team of unmanned aerial vehicles (UAVs) with non-ideal sensors and limited communication ranges. Our goal is to minimize the search time, while gathering more information about the environment and finding more targets. For this purpose, a novel cooperative search and coverage algorithm with controllable revisit mechanism is presented. Firstly, as the representation of the environment, the cognitive maps that included the target probability map (TPM), the uncertain map (UM), and the digital pheromone map (DPM) are constituted. We also design a distributed update and fusion scheme for the cognitive map. This update and fusion scheme can guarantee that each one of the cognitive maps converges to the same one, which reflects the targets’ true existence or absence in each cell of the search region. Secondly, we develop a controllable revisit mechanism based on the DPM. This mechanism can concentrate the UAVs to revisit sub-areas that have a large target probability or high uncertainty. Thirdly, in the frame of distributed receding horizon optimizing, a path planning algorithm for the multi-UAVs cooperative search and coverage is designed. In the path planning algorithm, the movement of the UAVs is restricted by the potential fields to meet the requirements of avoiding collision and maintaining connectivity constraints. Moreover, using the minimum spanning tree (MST) topology optimization strategy, we can obtain a tradeoff between the search coverage enhancement and the connectivity maintenance. The feasibility of the proposed algorithm is demonstrated by comparison simulations by way of analyzing the effects of the controllable revisit mechanism and the connectivity maintenance scheme. The Monte Carlo method is employed to validate the influence of the number of UAVs, the sensing radius, the detection and false alarm probabilities, and the communication range on the proposed algorithm.
Using known populations of pronghorn to evaluate sampling plans and estimators

USGS Publications Warehouse

Kraft, K.M.; Johnson, D.H.; Samuelson, J.M.; Allen, S.H.

1995-01-01

Although sampling plans and estimators of abundance have good theoretical properties, their performance in real situations is rarely assessed because true population sizes are unknown. We evaluated widely used sampling plans and estimators of population size on 3 known clustered distributions of pronghorn (Antilocapra americana). Our criteria were accuracy of the estimate, coverage of 95% confidence intervals, and cost. Sampling plans were combinations of sampling intensities (16, 33, and 50%), sample selection (simple random sampling without replacement, systematic sampling, and probability proportional to size sampling with replacement), and stratification. We paired sampling plans with suitable estimators (simple, ratio, and probability proportional to size). We used area of the sampling unit as the auxiliary variable for the ratio and probability proportional to size estimators. All estimators were nearly unbiased, but precision was generally low (overall mean coefficient of variation [CV] = 29). Coverage of 95% confidence intervals was only 89% because of the highly skewed distribution of the pronghorn counts and small sample sizes, especially with stratification. Stratification combined with accurate estimates of optimal stratum sample sizes increased precision, reducing the mean CV from 33 without stratification to 25 with stratification; costs increased 23%. Precise results (mean CV = 13) but poor confidence interval coverage (83%) were obtained with simple and ratio estimators when the allocation scheme included all sampling units in the stratum containing most pronghorn. Although areas of the sampling units varied, ratio estimators and probability proportional to size sampling did not increase precision, possibly because of the clumped distribution of pronghorn. Managers should be cautious in using sampling plans and estimators to estimate abundance of aggregated populations.
Health insurance coverage among women in Indonesia's major cities: A multilevel analysis.

PubMed

Christiani, Yodi; Byles, Julie E; Tavener, Meredith; Dugdale, Paul

2017-03-01

We examined women's access to health insurance in Indonesia. We analyzed IFLS-4 data of 1,400 adult women residing in four major cities. Among this population, the health insurance coverage was 24%. Women who were older, involved in paid work, and with higher education had greater access to health insurance (p < .05). We also found there were disparities in the probability of having health insurance across community levels (Median Odds Ratios = 3.40). Given the importance of health insurance for women's health, strategies should be developed to expand health insurance coverage among women in Indonesia, including the disparities across community levels. Such problems might also be encountered in other developing countries with low health insurance coverage.
COSPAS-SARSAT Satellite Orbit Predictor. Volume 3

NASA Technical Reports Server (NTRS)

Friedman, Morton L.; Garrett, James

1984-01-01

The satellite orbit predictor is a graphical aid for determining the relationship between the satellite (SARSAT or COSPAS) orbit, antenna coverage of the spacecraft and coverage of the LUTs. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite. Additionally, a table of equator crossings for each satellite is included.
Multi-Agent Cooperative Target Search

PubMed Central

Hu, Jinwen; Xie, Lihua; Xu, Jun; Xu, Zhao

2014-01-01

This paper addresses a vision-based cooperative search for multiple mobile ground targets by a group of unmanned aerial vehicles (UAVs) with limited sensing and communication capabilities. The airborne camera on each UAV has a limited field of view and its target discriminability varies as a function of altitude. First, by dividing the whole surveillance region into cells, a probability map can be formed for each UAV indicating the probability of target existence within each cell. Then, we propose a distributed probability map updating model which includes the fusion of measurement information, information sharing among neighboring agents, information decay and transmission due to environmental changes such as the target movement. Furthermore, we formulate the target search problem as a multi-agent cooperative coverage control problem by optimizing the collective coverage area and the detection performance. The proposed map updating model and the cooperative control scheme are distributed, i.e., assuming that each agent only communicates with its neighbors within its communication range. Finally, the effectiveness of the proposed algorithms is illustrated by simulation. PMID:24865884
Improving the analysis of composite endpoints in rare disease trials.

PubMed

McMenamin, Martina; Berglind, Anna; Wason, James M S

2018-05-22

Composite endpoints are recommended in rare diseases to increase power and/or to sufficiently capture complexity. Often, they are in the form of responder indices which contain a mixture of continuous and binary components. Analyses of these outcomes typically treat them as binary, thus only using the dichotomisations of continuous components. The augmented binary method offers a more efficient alternative and is therefore especially useful for rare diseases. Previous work has indicated the method may have poorer statistical properties when the sample size is small. Here we investigate small sample properties and implement small sample corrections. We re-sample from a previous trial with sample sizes varying from 30 to 80. We apply the standard binary and augmented binary methods and determine the power, type I error rate, coverage and average confidence interval width for each of the estimators. We implement Firth's adjustment for the binary component models and a small sample variance correction for the generalized estimating equations, applying the small sample adjusted methods to each sub-sample as before for comparison. For the log-odds treatment effect the power of the augmented binary method is 20-55% compared to 12-20% for the standard binary method. Both methods have approximately nominal type I error rates. The difference in response probabilities exhibit similar power but both unadjusted methods demonstrate type I error rates of 6-8%. The small sample corrected methods have approximately nominal type I error rates. On both scales, the reduction in average confidence interval width when using the adjusted augmented binary method is 17-18%. This is equivalent to requiring a 32% smaller sample size to achieve the same statistical power. The augmented binary method with small sample corrections provides a substantial improvement for rare disease trials using composite endpoints. We recommend the use of the method for the primary analysis in relevant rare disease trials. We emphasise that the method should be used alongside other efforts in improving the quality of evidence generated from rare disease trials rather than replace them.
Insurance coverage and prenatal care among low-income pregnant women: an assessment of states' adoption of the "Unborn Child" option in Medicaid and CHIP.

PubMed

Jarlenski, Marian P; Bennett, Wendy L; Barry, Colleen L; Bleich, Sara N

2014-01-01

The "Unborn Child" (UC) option provides state Medicaid/Children's Health Insurance Program (CHIP) programs with a new strategy to extend prenatal coverage to low-income women who would otherwise have difficulty enrolling in or would be ineligible for Medicaid. To examine the association of the UC option with the probability of enrollment in Medicaid/CHIP during pregnancy and probability of receiving adequate prenatal care. We use pooled cross-sectional data from the Pregnancy Risk Assessment Monitoring System from 32 states between 2004 and 2010 (n = 81,983). Multivariable regression is employed to examine the association of the UC option with Medicaid/CHIP enrollment during pregnancy among eligible women who were uninsured preconception (n = 45,082) and those who had insurance (but not Medicaid) preconception (n = 36,901). Multivariable regression is also employed to assess the association between the UC option and receipt of adequate prenatal care, measured by the Adequacy of Prenatal Care Utilization Index. Residing in a state with the UC option is associated with a greater probability of Medicaid enrollment during pregnancy relative to residing in a state without the policy both among women uninsured preconception (88% vs. 77%, P < 0.01) and among women insured (but not in Medicaid) preconception (40% vs. 31%, P < 0.01). Residing in a state with the UC option is not significantly associated with receiving adequate prenatal care, among both women with and without insurance preconception. The UC option provides states a key way to expand or simplify prenatal insurance coverage, but further policy efforts are needed to ensure that coverage improves access to high-quality prenatal care.
Extended Importance Sampling for Reliability Analysis under Evidence Theory

NASA Astrophysics Data System (ADS)

Yuan, X. K.; Chen, B.; Zhang, B. Q.

2018-05-01

In early engineering practice, the lack of data and information makes uncertainty difficult to deal with. However, evidence theory has been proposed to handle uncertainty with limited information as an alternative way to traditional probability theory. In this contribution, a simulation-based approach, called ‘Extended importance sampling’, is proposed based on evidence theory to handle problems with epistemic uncertainty. The proposed approach stems from the traditional importance sampling for reliability analysis under probability theory, and is developed to handle the problem with epistemic uncertainty. It first introduces a nominal instrumental probability density function (PDF) for every epistemic uncertainty variable, and thus an ‘equivalent’ reliability problem under probability theory is obtained. Then the samples of these variables are generated in a way of importance sampling. Based on these samples, the plausibility and belief (upper and lower bounds of probability) can be estimated. It is more efficient than direct Monte Carlo simulation. Numerical and engineering examples are given to illustrate the efficiency and feasible of the proposed approach.
Cost-Effectiveness of Opt-Out Chlamydia Testing for High-Risk Young Women in the U.S.

PubMed

Owusu-Edusei, Kwame; Hoover, Karen W; Gift, Thomas L

2016-08-01

In spite of chlamydia screening recommendations, U.S. testing coverage continues to be low. This study explored the cost-effectiveness of a patient-directed, universal, opportunistic Opt-Out Testing strategy (based on insurance coverage, healthcare utilization, and test acceptance probabilities) for all women aged 15-24 years compared with current Risk-Based Screening (30% coverage) from a societal perspective. Based on insurance coverage (80%); healthcare utilization (83%); and test acceptance (75%), the proposed Opt-Out Testing strategy would have an expected annual testing coverage of approximately 50% for sexually active women aged 15-24 years. A basic compartmental heterosexual transmission model was developed to account for population-level transmission dynamics. Two groups were assumed based on self-reported sexual activity. All model parameters were obtained from the literature. Costs and benefits were tracked over a 50-year period. The relative sensitivity of the estimated incremental cost-effectiveness ratios to the variables/parameters was determined. This study was conducted in 2014-2015. Based on the model, the Opt-Out Testing strategy decreased the overall chlamydia prevalence by >55% (2.7% to 1.2%). The Opt-Out Testing strategy was cost saving compared with the current Risk-Based Screening strategy. The estimated incremental cost-effectiveness ratio was most sensitive to the female pre-opt out prevalence, followed by the probability of female sequelae and discount rate. The proposed Opt-Out Testing strategy was cost saving, improving health outcomes at a lower net cost than current testing. However, testing gaps would remain because many women might not have health insurance coverage, or not utilize health care. Published by Elsevier Inc.
The effects of unequal access to health insurance for same-sex couples in California.

PubMed

Ponce, Ninez A; Cochran, Susan D; Pizer, Jennifer C; Mays, Vickie M

2010-08-01

Inequities in marriage laws and domestic partnership benefits may have implications for who bears the burden of health care costs. We examined a recent period in California to illuminate disparities in health insurance coverage faced by same-sex couples. Partnered gay men are less than half as likely (42 percent) as married heterosexual men to get employer-sponsored dependent coverage, and partnered lesbians have an even slimmer chance (28 percent) of getting dependent coverage compared to married heterosexual women. As a result of these much lower rates of employer-provided coverage, partnered lesbians and gay men are more than twice as likely to be uninsured as married heterosexuals. The exclusion of gay men and women from civil marriage and the failure of domestic partnership benefits to provide insurance parity contribute to unequal access to health coverage, with the probable result that more health spending is pushed onto these individuals and onto the public.
The Changing Dynamics Of US Health Insurance And Implications For The Future Of The Affordable Care Act.

PubMed

Graves, John A; Nikpay, Sayeh S

2017-02-01

The introduction of Medicaid expansions and state Marketplaces under the Affordable Care Act (ACA) have reduced the uninsurance rate to historic lows, changing the choices Americans make about coverage. In this article we shed light on these changing dynamics. We drew upon multistate transition models fit to nationally representative longitudinal data to estimate coverage transition probabilities between major insurance types in the years leading up to and including 2014. We found that the ACA's unprecedented coverage changes increased transitions to Medicaid and nongroup coverage among the uninsured, while strengthening the existing employer-sponsored insurance system and improving retention of public coverage. However, our results suggest possible weakness of state Marketplaces, since people gaining nongroup coverage were disproportionately older than other potential enrollees. We identified key opportunities for policy makers and insurers to improve underlying Marketplace risk pools by focusing on people transitioning from employer-sponsored coverage; these people are disproportionately younger and saw almost no change in their likelihood of becoming uninsured in 2014 compared to earlier years. Project HOPE—The People-to-People Health Foundation, Inc.
Role of ultrathin metal fluoride layer in organic photovoltaic cells: mechanism of efficiency and lifetime enhancement.

PubMed

Lim, Kyung-Geun; Choi, Mi-Ri; Kim, Ji-Hoon; Kim, Dong Hun; Jung, Gwan Ho; Park, Yongsup; Lee, Jong-Lam; Lee, Tae-Woo

2014-04-01

Although rapid progress has been made recently in bulk heterojunction organic solar cells, systematic studies on an ultrathin interfacial layer at the electron extraction contact have not been conducted in detail, which is important to improve both the device efficiency and the lifetime. We find that an ultrathin BaF2 layer at the electron extraction contact strongly influences the open-circuit voltage (Voc ) as the nanomorphology evolves with increasing BaF2 thickness. A vacuum-deposited ultrathin BaF2 layer grows by island growth, so BaF2 layers with a nominal thickness less than that of single-coverage layer (≈3 nm) partially cover the polymeric photoactive layer. As the nominal thickness of the BaF2 layer increased to that of a single-coverage layer, the Voc and power conversion efficiency (PCE) of the organic photovoltaic cells (OPVs) increased but the short-circuit current remained almost constant. The fill factor and the PCE decreased abruptly as the thickness of the BaF2 layer exceeded that of a single-coverage layer, which was ascribed to the insulating nature of BaF2 . We find the major cause of the increased Voc observed in these devices is the lowered work function of the cathode caused by the reaction and release of Ba from thin BaF2 films upon deposition of Al. The OPV device with the BaF2 layer showed a slightly improved maximum PCE (4.0 %) and a greatly (approximately nine times) increased device half-life under continuous simulated solar irradiation at 100 mW cm(-2) as compared with the OPV without an interfacial layer (PCE=2.1 %). We found that the photodegradation of the photoactive layer was not a major cause of the OPV degradation. The hugely improved lifetime with cathode interface modification suggests a significant role of the cathode interfacial layer that can help to prolong device lifetimes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Demonstration of Orbit Determination for the Lunar Reconnaissance Orbiter Using One-Way Laser Ranging Data

NASA Technical Reports Server (NTRS)

Bauer, S.; Hussmann, H.; Oberst, J.; Dirkx, D.; Mao, D.; Neumann, G. A.; Mazarico, E.; Torrence, M. H.; McGarry, J. F.; Smith, D. E.;

2016-01-01

We used one-way laser ranging data from International Laser Ranging Service (ILRS) ground stations to NASA's Lunar Reconnaissance Orbiter (LRO) for a demonstration of orbit determination. In the one-way setup, the state of LRO and the parameters of the spacecraft and all involved ground station clocks must be estimated simultaneously. This setup introduces many correlated parameters that are resolved by using a priori constraints. More over the observation data coverage and errors accumulating from the dynamical and the clock modeling limit the maximum arc length. The objective of this paper is to investigate the effect of the arc length, the dynamical and modeling accuracy and the observation data coverage on the accuracy of the results. We analyzed multiple arcs using lengths of 2 and 7 days during a one-week period in Science Mission phase 02 (SM02,November2010) and compared the trajectories, the post-fit measurement residuals and the estimated clock parameters. We further incorporated simultaneous passes from multiple stations within the observation data to investigate the expected improvement in positioning. The estimated trajectories were compared to the nominal LRO trajectory and the clock parameters (offset, rate and aging) to the results found in the literature. Arcs estimated with one-way ranging data had differences of 5-30 m compared to the nominal LRO trajectory. While the estimated LRO clock rates agreed closely with the a priori constraints, the aging parameters absorbed clock modeling errors with increasing clock arc length. Because of high correlations between the different ground station clocks and due to limited clock modeling accuracy, their differences only agreed at the order of magnitude with the literature. We found that the incorporation of simultaneous passes requires improved modeling in particular to enable the expected improvement in positioning. We found that gaps in the observation data coverage over 12h (approximately equals 6 successive LRO orbits) prevented the successful estimation of arcs with lengths shorter or longer than 2 or 7 days with our given modeling.

Photon-enhanced thermionic emission from p-GaAs with nonequilibrium Cs overlayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuravlev, A. G.; Romanov, A. S.; Alperovich, V. L., E-mail: alper@isp.nsc.ru

2014-12-22

Photon-enhanced thermionic emission (PETE), which is promising for increasing the efficiency of solar energy conversion, is studied during cesium deposition on the As- and Ga-rich p-GaAs(001) surfaces and subsequent relaxation in the nonequilibrium Cs overlayer by means of photoemission quantum yield spectroscopy adapted for systems with time-variable parameters. Along with direct photoemission of “hot” electrons excited by light above the vacuum level, the spectra contain PETE contribution of “thermalized” electrons, which are excited below the vacuum level and emit in vacuum due to thermalization up in energy by phonon absorption. Comparing the measured and calculated spectra, the effective electron affinitymore » and escape probabilities of hot and thermalized electrons are obtained as functions of submonolayer Cs coverage. The minima in the affinity and pronounced peaks in the escape probabilities are observed for Cs deposition on both the As- and Ga-rich surfaces. Possible reasons for the low mean values of the electron escape probabilities and for the observed enhancement of the probabilities at certain Cs coverages are discussed, along with the implications for the PETE device realization.« less
Predicting the evolution of spreading on complex networks

PubMed Central

Chen, Duan-Bing; Xiao, Rui; Zeng, An

2014-01-01

Due to the wide applications, spreading processes on complex networks have been intensively studied. However, one of the most fundamental problems has not yet been well addressed: predicting the evolution of spreading based on a given snapshot of the propagation on networks. With this problem solved, one can accelerate or slow down the spreading in advance if the predicted propagation result is narrower or wider than expected. In this paper, we propose an iterative algorithm to estimate the infection probability of the spreading process and then apply it to a mean-field approach to predict the spreading coverage. The validation of the method is performed in both artificial and real networks. The results show that our method is accurate in both infection probability estimation and spreading coverage prediction. PMID:25130862
Planetary Protection Trajectory Analysis for the Juno Mission

NASA Technical Reports Server (NTRS)

Lam, Try; Johannesen, Jennie R.; Kowalkowski, Theresa D.

2008-01-01

Juno is an orbiter mission expected to launch in 2011 to Jupiter. Juno's science orbit is a highly eccentric orbit with a period of about 11 days and a nominal duration of one year. Initially, the equatorial crossing near apojove occurs outside Callisto's orbit, but as the mission evolves the apsidal rotation causes this distance to move much closer to Jupiter. This motion could lead to potential impacts with the Galilean satellites as the ascending node crosses the satellite orbits. In this paper, we describe the method to estimate impact probabilities with the satellites and investigate ways of reducing the probabilities for the Juno mission.
SU-E-T-551: PTV Is the Worst-Case of CTV in Photon Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harrington, D; Liu, W; Park, P

2014-06-01

Purpose: To examine the supposition of the static dose cloud and adequacy of the planning target volume (PTV) dose distribution as the worst-case representation of clinical target volume (CTV) dose distribution for photon therapy in head and neck (H and N) plans. Methods: Five diverse H and N plans clinically delivered at our institution were selected. Isocenter for each plan was shifted positively and negatively in the three cardinal directions by a displacement equal to the PTV expansion on the CTV (3 mm) for a total of six shifted plans per original plan. The perturbed plan dose was recalculated inmore » Eclipse (AAA v11.0.30) using the same, fixed fluence map as the original plan. The dose distributions for all plans were exported from the treatment planning system to determine the worst-case CTV dose distributions for each nominal plan. Two worst-case distributions, cold and hot, were defined by selecting the minimum or maximum dose per voxel from all the perturbed plans. The resulting dose volume histograms (DVH) were examined to evaluate the worst-case CTV and nominal PTV dose distributions. Results: Inspection demonstrates that the CTV DVH in the nominal dose distribution is indeed bounded by the CTV DVHs in the worst-case dose distributions. Furthermore, comparison of the D95% for the worst-case (cold) CTV and nominal PTV distributions by Pearson's chi-square test shows excellent agreement for all plans. Conclusion: The assumption that the nominal dose distribution for PTV represents the worst-case dose distribution for CTV appears valid for the five plans under examination. Although the worst-case dose distributions are unphysical since the dose per voxel is chosen independently, the cold worst-case distribution serves as a lower bound for the worst-case possible CTV coverage. Minor discrepancies between the nominal PTV dose distribution and worst-case CTV dose distribution are expected since the dose cloud is not strictly static. This research was supported by the NCI through grant K25CA168984, by The Lawrence W. and Marilyn W. Matteson Fund for Cancer Research, and by the Fraternal Order of Eagles Cancer Research Fund, the Career Development Award Program at Mayo Clinic.« less
Taking up or turning down: new estimates of household demand for employer-sponsored health insurance.

PubMed

Abraham, Jean Marie; Feldman, Roger

2010-01-01

This study provides new estimates of demand for employer-sponsored health insurance, using the 1997-2001 linked Household Component-Insurance Component of the Medical Expenditure Panel Survey (MEPS). Our focus is on households' decisions to take up coverage through a worker's employer. We found a significant inverse relationship between the out-of-pocket premium and the probability of taking up coverage, with the price effect considerably larger when we used instrumental variables methods to account for endogenous out-of-pocket premiums. Additionally, workers in families with more children eligible for Medicaid were less likely to take up coverage.
Overlayer growth and electronic properties of the Bi/GaSb(110) interface

NASA Astrophysics Data System (ADS)

Gavioli, Luca; Betti, Maria Grazia; Casarini, Paolo; Mariani, Carlo

1995-06-01

The overlayer growth and electronic properties of the Bi/GaSb(110) interface and of the two-dimensional ordered (1×1)- and (1×2)-Bi layers have been investigated by complementary spectroscopic techniques (high-resolution electron-energy-loss, photoemission, and Auger spectroscopy). Bismuth forms an epitaxial monolayer, followed by island formation (Stranski-Krastanov growth mode) covering an average surface area of 40% at a nominal coverage of 4 ML. The (1×2)-symmetry stable structural phase, obtained after annealing at ~220 °C, corresponds to an average nominal Bi coverage of about 0.7 ML, suggesting an atomic geometry different from the epitaxial-continued layer structure. The disposal of Bi atoms in the (1×2) structure should build up an ``open'' layer, as the Ga-related surface exciton quenched in the (1×1) epitaxial monolayer is present in the (1×2) stable phase. The two symmetry phases are characterized by strong absorption features at 1 eV [(1×1)-Bi] and 0.54 eV [(1×2)-Bi], related to interband electronic transitions between Bi-induced electronic states. The major Bi-related occupied electronic levels, present in the valence band of the (1×1)- and (1×2)-Bi layer, have been detected by angle-integrated ultraviolet photoemission spectroscopy. Both the (1×1) and (1×2) phases show a metallic nature, with a low density of electronic states at the Fermi level. Schottky barrier heights of 0.20 and 0.14 eV are estimated for the epitaxial (1×1)- and (1×2)-symmetry stage, respectively, by analyzing the space-charge layer conditions through the study of the dopant-induced free-carrier plasmon in the GaSb substrate.
a Photoemission Study of the Electronic Structure Induced by Potassium Adsorption on TiO2(110)

NASA Astrophysics Data System (ADS)

Heise, Rainer; Courths, Ralf

Electronic structure effects induced by potassium adsorption up to one monolayer (ML) on a nearly stoichiometric TiO2(110) surface has been studied by means of angle-resolved photoemission spectroscopy (ARUPS and ARXPS) from valence states and core levels. In agreement with the observations on K/TiO2(100) [P.J. Hardman et al., Surf. Sci. 269/270, 677 (1992)], potassium adsorption at room temperature leads—due to K-to-substrate charge transfer—to the reduction of surface Ti ions (to nominally Ti3+ ions), evidenced by lowered Ti 2p core-level binding energy (ΔBE=-1.6 eV) and occupation of Ti 3d-like band-gap states centered at 0.9 eV BE. The gap-state intensity exhibits a pronounced maximum at 0.37 ML coverage, where the work function has a weak minimum. This behavior is in agreement with a ionic-to-neutral transition of the K-substrate bonding with increasing K coverage, as suggested recently [Souda et al., Surf. Sci. 285, 265 (1993)]. Annealing of a surface precovered with 0.27 ML potassium up to 1000 K results in metallization of the surface, evidenced by (i) the occupation of a second gap-state centered at 0.4 BE and with a considerable state-density at the Fermi energy, and (ii) Ti 2p core-levels lowered by 3.2 eV in BE (nominally “Ti2+” ions). This dramatic reduction of the surface is healed out with complete desorption of potassium. A discussion in terms of desorption of KOx species and oxygen diffusion from the bulk to the surface is given.

Multicriteria decision analysis for including health interventions in the universal health coverage benefit package in Thailand.

PubMed

Youngkong, Sitaporn; Baltussen, Rob; Tantivess, Sripen; Mohara, Adun; Teerawattananon, Yot

2012-01-01

Considering rising health expenditure on the one hand and increasing public expectations on the other hand, there is a need for explicit health care rationing to secure public acceptance of coverage decisions of health interventions. The National Health Security Office, the institute managing the Universal Coverage Scheme in Thailand, recently called for more rational, transparent, and fair decisions on the public reimbursement of health interventions. This article describes the application of multicriteria decision analysis (MCDA) to guide the coverage decisions on including health interventions in the Universal Coverage Scheme health benefit package in the period 2009-2010. We described the MCDA priority-setting process through participatory observation and evaluated the rational, transparency, and fairness of the priority-setting process against the accountability for reasonableness framework. The MCDA was applied in four steps: 1) 17 interventions were nominated for assessment; 2) nine interventions were selected for further quantitative assessment on the basis of the following criteria: size of population affected by disease, severity of disease, effectiveness of health intervention, variation in practice, economic impact on household expenditure, and equity and social implications; 3) these interventions were then assessed in terms of cost-effectiveness and budget impact; and 4) decision makers qualitatively appraised, deliberated, and reached consensus on which interventions should be adopted in the package. This project was carried out in a real-world context and has considerably contributed to the rational, transparent, and fair priority-setting process through the application of MCDA. Although the present project has applied MCDA in the Thai context, MCDA is adaptable to other settings. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
Kinetic aspects of chain growth in Fischer-Tropsch synthesis.

PubMed

Filot, Ivo A W; Zijlstra, Bart; Broos, Robin J P; Chen, Wei; Pestman, Robert; Hensen, Emiel J M

2017-04-28

Microkinetics simulations are used to investigate the elementary reaction steps that control chain growth in the Fischer-Tropsch reaction. Chain growth in the FT reaction on stepped Ru surfaces proceeds via coupling of CH and CR surface intermediates. Essential to the growth mechanism are C-H dehydrogenation and C hydrogenation steps, whose kinetic consequences have been examined by formulating two novel kinetic concepts, the degree of chain-growth probability control and the thermodynamic degree of chain-growth probability control. For Ru the CO conversion rate is controlled by the removal of O atoms from the catalytic surface. The temperature of maximum CO conversion rate is higher than the temperature to obtain maximum chain-growth probability. Both maxima are determined by Sabatier behavior, but the steps that control chain-growth probability are different from those that control the overall rate. Below the optimum for obtaining long hydrocarbon chains, the reaction is limited by the high total surface coverage: in the absence of sufficient vacancies the CHCHR → CCHR + H reaction is slowed down. Beyond the optimum in chain-growth probability, CHCR + H → CHCHR and OH + H → H 2 O limit the chain-growth process. The thermodynamic degree of chain-growth probability control emphasizes the critical role of the H and free-site coverage and shows that at high temperature, chain depolymerization contributes to the decreased chain-growth probability. That is to say, during the FT reaction chain growth is much faster than chain depolymerization, which ensures high chain-growth probability. The chain-growth rate is also fast compared to chain-growth termination and the steps that control the overall CO conversion rate, which are O removal steps for Ru.
Herbal medicine use and linked suspected adverse drug reactions in a prospective cohort of Ugandan inpatients.

PubMed

Kiguba, Ronald; Ononge, Sam; Karamagi, Charles; Bird, Sheila M

2016-05-26

Clinical history-taking can be employed as a standardized approach to elucidate the use of herbal medicines and their linked suspected adverse drug reactions (ADRs) among hospitalized patients. We sought to identify herbal medicines nominated by Ugandan inpatients; compare nomination rates by ward and gender; confirm the herbs' known pharmacological properties from published literature; and identify ADRs linked to pre-admission use of herbal medicines. Prospective cohort of consented adult inpatients designed to assess medication use and ADRs on one gynaecological and three medical wards of 1790-bed Mulago National Referral Hospital. Baseline and follow-up data were obtained on patients' characteristics, including pre-admission use of herbal medicines. Fourteen percent (26/191) of females in Gynaecology nominated at least one specific herbal medicine compared with 20 % (114/571) of inpatients on medical wards [20 % (69/343) of females; 20 % (45/228) of males]. Frequent nominations were Persea americana (30), Mumbwa/multiple-herb clay rods (23), Aloe barbadensis (22), Beta vulgaris (12), Vernonia amygdalina (11), Commelina africana (7), Bidens pilosa (7), Hoslundia opposita (6), Mangifera indica (4), and Dicliptera laxata (4). Four inpatients experienced 10 suspected ADRs linked to pre-admission herbal medicine use including Commelina africana (4), multiple-herb-mumbwa (1), or unspecified local-herbs (5): three ADR-cases were abortion-related and one kidney-related. The named herbal medicines and their nomination rates generally differed by specialized ward, probably guided by local folklore knowledge of their use. Clinical elicitation from inpatients can generate valuable safety data on herbal medicine use. However, larger routine studies might increase the utility of our method to assess herbal medicine use and detect herb-linked ADRs. Future studies should take testable samples of ADR-implicated herbal medicines for further analysis.
Evolution of Space Shuttle Range Safety (RS) Ascent Flight Envelope Design

NASA Technical Reports Server (NTRS)

Brewer, Joan D.

2011-01-01

Ascent flight envelopes are trajectories that define the normal operating region of a space vehicle s position from liftoff until the end of powered flight. They fulfill part of the RS data requirements imposed by the Air Force s 45th Space Wing (45SW) on space vehicles launching from the Eastern Range (ER) in Florida. The 45SW is chartered to protect the public by minimizing risks associated with the inherent hazards of launching a vehicle into space. NASA s Space Shuttle program has launched 130+ manned missions over a 30 year period from the ER. Ascent envelopes were delivered for each of those missions. The 45SW envelope requirements have remained largely unchanged during this time. However, the methodology and design processes used to generate the envelopes have evolved over the years to support mission changes, maintain high data quality, and reduce costs. The evolution of the Shuttle envelope design has yielded lessons learned that can be applied to future endevours. There have been numerous Shuttle ascent design enhancements over the years that have caused the envelope methodology to evolve. One of these Shuttle improvements was the introduction of onboard flight software changes implemented to improve launch probability. This change impacted the preflight nominal ascent trajectory, which is a key element in the RS envelope design. While the early Shuttle nominal trajectories were designed preflight using a representative monthly mean wind, the new software changes involved designing a nominal ascent trajectory on launch day using real-time winds. Because the actual nominal trajectory position was not known until launch day, the envelope analysis had to be customized to account for this nominal trajectory variation in addition to the other envelope components.
Distribution, characterization, and exposure of MC252 oil in the supratidal beach environment.

PubMed

Lemelle, Kendall R; Elango, Vijaikrishnah; Pardue, John H

2014-07-01

The distribution and characteristics of MC252 oil:sand aggregates, termed surface residue balls (SRBs), were measured on the supratidal beach environment of oil-impacted Fourchon Beach in Louisiana (USA). Probability distributions of 4 variables, surface coverage (%), size of SRBs (mm(2) of projected area), mass of SRBs per m(2) (g/m(2)), and concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the SRBs (mg of crude oil component per kg of SRB) were determined using parametric and nonparametric statistical techniques. Surface coverage of SRBs, an operational remedial standard for the beach surface, was a gamma-distributed variable ranging from 0.01% to 8.1%. The SRB sizes had a mean of 90.7 mm(2) but fit no probability distribution, and a nonparametric ranking was used to describe the size distributions. Concentrations of total PAHs ranged from 2.5 mg/kg to 126 mg/kg of SRB. Individual PAH concentration distributions, consisting primarily of alkylated phenanthrenes, dibenzothiophenes, and chrysenes, did not consistently fit a parametric distribution. Surface coverage was correlated with an oil mass per unit area but with a substantial error at lower coverage (i.e., <2%). These data provide probabilistic risk assessors with the ability to specify uncertainty in PAH concentration, exposure frequency, and ingestion rate, based on SRB characteristics for the dominant oil form on beaches along the US Gulf Coast. © 2014 SETAC.
Fluorine atom abstraction by Si(100). I. Experimental

NASA Astrophysics Data System (ADS)

Tate, M. R.; Gosalvez-Blanco, D.; Pullman, D. P.; Tsekouras, A. A.; Li, Y. L.; Yang, J. J.; Laughlin, K. B.; Eckman, S. C.; Bertino, M. F.; Ceyer, S. T.

1999-08-01

In the interaction of low energy F2 with Si(100) at 250 K, a dissociative chemisorption mechanism called atom abstraction is identified in which only one of the F atoms is adsorbed while the other F atom is scattered into the gas phase. The dynamics of atom abstraction are characterized via time-of-flight measurements of the scattered F atoms. The F atoms are translationally hyperthermal but only carry a small fraction (˜3%) of the tremendous exothermicity of the reaction. The angular distribution of F atoms is unusually broad for the product of an exothermic reaction. These results suggest an "attractive" interaction potential between F2 and the Si dangling bond with a transition state that is not constrained geometrically. These results are in disagreement with the results of theoretical investigations implying that the available potential energy surfaces are inadequate to describe the dynamics of this gas-surface interaction. In addition to single atom abstraction, two atom adsorption, a mechanism analogous to classic dissociative chemisorption in which both F atoms are adsorbed onto the surface, is also observed. The absolute probability of the three scattering channels (single atom abstraction, two atom adsorption, and unreactive scattering) for an incident F2 are determined as a function of F2 exposure. The fluorine coverage is determined by integrating the reaction probabilities over F2 exposure, and the reaction probabilities are recast as a function of fluorine coverage. Two atom adsorption is the dominant channel [P2=0.83±0.03(95%, N=9)] in the limit of zero coverage and decays monotonically to zero. Single atom abstraction is the minor channel (P1=0.13±0.03) at low coverage but increases to a maximum (P1=0.35±0.08) at about 0.5 monolayer (ML) coverage before decaying to zero. The reaction ceases at 0.94±0.11(95%, N=9) ML. Thermal desorption and helium diffraction confirm that the dangling bonds are the abstraction and adsorption sites. No Si lattice bonds are broken, in contrast to speculation by other investigators that the reaction exothermicity causes lattice disorder.
Crew Exploration Vehicle Service Module Ascent Abort Coverage

NASA Technical Reports Server (NTRS)

Tedesco, Mark B.; Evans, Bryan M.; Merritt, Deborah S.; Falck, Robert D.

2007-01-01

The Crew Exploration Vehicle (CEV) is required to maintain continuous abort capability from lift off through destination arrival. This requirement is driven by the desire to provide the capability to safely return the crew to Earth after failure scenarios during the various phases of the mission. This paper addresses abort trajectory design considerations, concept of operations and guidance algorithm prototypes for the portion of the ascent trajectory following nominal jettison of the Launch Abort System (LAS) until safe orbit insertion. Factors such as abort system performance, crew load limits, natural environments, crew recovery, and vehicle element disposal were investigated to determine how to achieve continuous vehicle abort capability.
Low-energy particle experiments-ion mass analyzer (LEPi) onboard the ERG (Arase) satellite

NASA Astrophysics Data System (ADS)

Asamura, K.; Kazama, Y.; Yokota, S.; Kasahara, S.; Miyoshi, Y.

2018-05-01

Low-energy ion experiments-ion mass analyzer (LEPi) is one of the particle instruments onboard the ERG satellite. LEPi is an ion energy-mass spectrometer which covers the range of particle energies from < 0.01 to 25 keV/q. Species of incoming ions are discriminated by a combination of electrostatic energy-per-charge analysis and the time-of-flight technique. The sensor has a planar field-of-view, which provides 4π steradian coverage by using the spin motion of the satellite. LEPi started its nominal observation after the initial checkout and commissioning phase in space. [Figure not available: see fulltext.
Surface states and annihilation characteristics of positrons trapped at the oxidized Cu(100) surface

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Weiss, A. H.

2013-06-01

In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. Oxidation of the Cu(100) surface has been studied by performing an ab-initio investigation of the stability and electronic structure of the Cu(100) missing row reconstructed surface at various on-surface and subsurface oxygen coverages ranging from 0.5 to 1.5 monolayers using density functional theory (DFT). All studied structures have been found to be energetically more favorable as compared to structures formed by purely on-surface oxygen adsorption. The observed decrease in the positron work function when oxygen atoms occupy on-surface and subsurface sites has been attributed to a significant charge redistribution within the first two layers, buckling effects within each layer and an interlayer expansion. The computed positron binding energy, positron surface state wave function, and annihilation probabilities of the surface trapped positrons with relevant core electrons demonstrate their sensitivity to oxygen coverage, atomic structure of the topmost layers of surfaces, and charge transfer effects. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES). The results presented provide an explanation for the changes observed in the probability of annihilation of surface trapped positrons with Cu 3p core-level electrons as a function of annealing temperature.
Saturn's icy satellites investigated by Cassini-VIMS. II. Results at the end of nominal mission

USGS Publications Warehouse

Filacchione, G.; Capaccioni, F.; Clark, R.N.; Cuzzi, J.N.; Cruikshank, D.P.; Coradini, A.; Cerroni, P.; Nicholson, P.D.; McCord, T.B.; Brown, R.H.; Buratti, B.J.; Tosi, F.; Nelson, R.M.; Jaumann, R.; Stephan, K.

2010-01-01

We report the detailed analysis of the spectrophotometric properties of Saturn's icy satellites as derived by full-disk observations obtained by visual and infrared mapping spectrometer (VIMS) experiment aboard Cassini. In this paper, we have extended the coverage until the end of the Cassini's nominal mission (June 1st 2008), while a previous paper (Filacchione, G., and 28 colleagues [2007]. Icarus 186, 259-290, hereby referred to as Paper I) reported the preliminary results of this study. During the four years of nominal mission, VIMS has observed the entire population of Saturn's icy satellites allowing us to make a comparative analysis of the VIS-NIR spectral properties of the major satellites (Mimas, Enceladus, Tethys, Dione, Rhea, Hyperion, Iapetus) and irregular moons (Atlas, Prometheus, Pandora, Janus, Epimetheus, Telesto, Calypso, Phoebe). The results we discuss here are derived from the entire dataset available at June 2008 which consists of 1417 full-disk observations acquired from a variety of distances and inclinations from the equatorial plane, with different phase angles and hemispheric coverage. The most important spectrophotometric indicators (as defined in Paper I: I/F continua at 0.55 ??m, 1.822 ??m and 3.547 ??m, visible spectral slopes, water and carbon dioxide bands depths and positions) are calculated for each observation in order to investigate the disk-integrated composition of the satellites, the distribution of water ice respect to "contaminants" abundances and typical regolith grain properties. These quantities vary from the almost pure water ice surfaces of Enceladus and Calypso to the organic and carbon dioxide rich Hyperion, Iapetus and Phoebe. Janus visible colors are intermediate between these two classes having a slightly positive spectral slope. These results could help to decipher the origins and evolutionary history of the minor moons of the Saturn's system. We introduce a polar representation of the spectrophotometric parameters as function of the solar phase angle (along radial distance) and of the effective longitude interval illuminated by the Sun and covered by VIMS during the observation (in azimuth) to better investigate the spatial distribution of the spectrophotometric quantities across the regular satellites hemispheres. Finally, we report the observed spectral positions of the 4.26 ??m band of the carbon dioxide present in the surface material of three outermost moons Hyperion, Iapetus and Phoebe. ?? 2009 Elsevier Inc.
Workers on the margin: who drops health coverage when prices rise?

PubMed

Okeke, Edward N; Hirth, Richard A; Grazier, Kyle

2010-01-01

We revisit the question of price elasticity of employer-sponsored insurance (ESI) take-up by directly examining changes in the take-up of ESI at a large firm in response to exogenous changes in employee premium contributions. We find that, on average, a 10% increase in the employee's out-of-pocket premium increases the probability of dropping coverage by approximately 1%. More importantly, we find heterogeneous impacts: married workers are much more price-sensitive than single employees, and lower-paid workers are disproportionately more likely to drop coverage than higher-paid workers. Elasticity estimates for employees below the 25th percentile of salary distribution in our sample are nearly twice the average.
Predicting longitudinal trajectories of health probabilities with random-effects multinomial logit regression.

PubMed

Liu, Xian; Engel, Charles C

2012-12-20

Researchers often encounter longitudinal health data characterized with three or more ordinal or nominal categories. Random-effects multinomial logit models are generally applied to account for potential lack of independence inherent in such clustered data. When parameter estimates are used to describe longitudinal processes, however, random effects, both between and within individuals, need to be retransformed for correctly predicting outcome probabilities. This study attempts to go beyond existing work by developing a retransformation method that derives longitudinal growth trajectories of unbiased health probabilities. We estimated variances of the predicted probabilities by using the delta method. Additionally, we transformed the covariates' regression coefficients on the multinomial logit function, not substantively meaningful, to the conditional effects on the predicted probabilities. The empirical illustration uses the longitudinal data from the Asset and Health Dynamics among the Oldest Old. Our analysis compared three sets of the predicted probabilities of three health states at six time points, obtained from, respectively, the retransformation method, the best linear unbiased prediction, and the fixed-effects approach. The results demonstrate that neglect of retransforming random errors in the random-effects multinomial logit model results in severely biased longitudinal trajectories of health probabilities as well as overestimated effects of covariates on the probabilities. Copyright © 2012 John Wiley & Sons, Ltd.
Studies of high coverage oxidation of the Cu(100) surface using low energy positrons

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Maddox, W. B.; Weiss, A. H.

2012-02-01

The study of oxidation of single crystal metal surfaces is important in understanding the corrosive and catalytic processes associated with thin film metal oxides. The structures formed on oxidized transition metal surfaces vary from simple adlayers of chemisorbed oxygen to more complex structures which result from the diffusion of oxygen into subsurface regions. In this work we present the results of theoretical studies of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. Calculations are performed for various high coverage missing row structures ranging between 0.50 and 1.50 ML oxygen coverage. The results of calculations of positron binding energy, positron work function, and annihilation characteristics of surface trapped positrons with relevant core electrons as function of oxygen coverage are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy (PAES).
The Effects Of Unequal Access To Health Insurance For Same-Sex Couples In California

PubMed Central

Ponce, Ninez A.; Cochran, Susan D.; Pizer, Jennifer C.; Mays, Vickie M.

2013-01-01

Inequities in marriage laws and domestic partnership benefits may have implications for who bears the burden of health care costs. We examined a recent period in California to illuminate disparities in health insurance coverage faced by same-sex couples. Partnered gay men are less than half as likely (42 percent) as married heterosexual men to get employer-sponsored dependent coverage, and partnered lesbians have an even slimmer chance (28 percent) of getting dependent coverage compared to married heterosexual women. As a result of these much lower rates of employer-provided coverage, partnered lesbians and gay men are more than twice as likely to be uninsured as married heterosexuals. The exclusion of gay men and women from civil marriage and the failure of domestic partnership benefits to provide insurance parity contribute to unequal access to health coverage, with the probable result that more health spending is pushed onto these individuals and onto the public. PMID:20576694
Examples of S1 coverage intervals with very good and very bad long-run success rate

NASA Astrophysics Data System (ADS)

Giaquinto, Nicola; Fabbiano, Laura

2016-04-01

The paper illustrates, by means of selected examples, the merits and the limits of the method for computing coverage intervals described in the Supplement 1 to the GUM. The assessment of coverage intervals is done by evaluating their long-run success rate. Three pairs of examples are presented, relative to three different ways of generating incomplete knowledge about quantities: toss of dice, presence of additive noise, quantization. In all the pairs of examples, the first one results in a coverage interval with a long-run success rate equal to the coverage probability (set to 95%); the second one, instead, yields an interval with a success rate near to zero. The paper shows that the propagation mechanism of the Supplement 1, while working well in certain special cases, yields unacceptable results in others, and that the problematic issues cannot be neglected. The conclusion is that, if a Bayesian approach to uncertainty evaluation is adopted, the propagation is a particularly delicate issue.
Determination of celestial bodies orbits and probabilities of their collisions with the Earth

NASA Astrophysics Data System (ADS)

Medvedev, Yuri; Vavilov, Dmitrii

In this work we have developed a universal method to determine the small bodies orbits in the Solar System. In the method we consider different planes of body’s motion and pick up which is the most appropriate. Given an orbit plane we can calculate geocentric distances at time of observations and consequence determinate all orbital elements. Another technique that we propose here addresses the problem of estimation probability of collisions celestial bodies with the Earth. This technique uses the coordinate system associated with the nominal osculating orbit. We have compared proposed technique with the Monte-Carlo simulation. Results of these methods exhibit satisfactory agreement, whereas, proposed method is advantageous in time performance.
Dose coverage calculation using a statistical shape model—applied to cervical cancer radiotherapy

NASA Astrophysics Data System (ADS)

Tilly, David; van de Schoot, Agustinus J. A. J.; Grusell, Erik; Bel, Arjan; Ahnesjö, Anders

2017-05-01

A comprehensive methodology for treatment simulation and evaluation of dose coverage probabilities is presented where a population based statistical shape model (SSM) provide samples of fraction specific patient geometry deformations. The learning data consists of vector fields from deformable image registration of repeated imaging giving intra-patient deformations which are mapped to an average patient serving as a common frame of reference. The SSM is created by extracting the most dominating eigenmodes through principal component analysis of the deformations from all patients. The sampling of a deformation is thus reduced to sampling weights for enough of the most dominating eigenmodes that describe the deformations. For the cervical cancer patient datasets in this work, we found seven eigenmodes to be sufficient to capture 90% of the variance in the deformations of the, and only three eigenmodes for stability in the simulated dose coverage probabilities. The normality assumption of the eigenmode weights was tested and found relevant for the 20 most dominating eigenmodes except for the first. Individualization of the SSM is demonstrated to be improved using two deformation samples from a new patient. The probabilistic evaluation provided additional information about the trade-offs compared to the conventional single dataset treatment planning.
Link Connectivity and Coverage of Underwater Cognitive Acoustic Networks under Spectrum Constraint

PubMed Central

Wang, Qiu; Cheang, Chak Fong

2017-01-01

Extensive attention has been given to the use of cognitive radio technology in underwater acoustic networks since the acoustic spectrum became scarce due to the proliferation of human aquatic activities. Most of the recent studies on underwater cognitive acoustic networks (UCANs) mainly focus on spectrum management or protocol design. Few efforts have addressed the quality-of-service (QoS) of UCANs. In UCANs, secondary users (SUs) have lower priority to use acoustic spectrum than primary users (PUs) with higher priority to access spectrum. As a result, the QoS of SUs is difficult to ensure in UCANs. This paper proposes an analytical model to investigate the link connectivity and the probability of coverage of SUs in UCANs. In particular, this model takes both topological connectivity and spectrum availability into account, though spectrum availability has been ignored in most recent studies. We conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Simulation results show that our proposed model is quite accurate. Besides, our results also imply that the link connectivity and the probability of coverage of SUs heavily depend on both the underwater acoustic channel conditions and the activities of PUs. PMID:29215561
Bayes factor and posterior probability: Complementary statistical evidence to p-value.

PubMed

Lin, Ruitao; Yin, Guosheng

2015-09-01

As a convention, a p-value is often computed in hypothesis testing and compared with the nominal level of 0.05 to determine whether to reject the null hypothesis. Although the smaller the p-value, the more significant the statistical test, it is difficult to perceive the p-value in a probability scale and quantify it as the strength of the data against the null hypothesis. In contrast, the Bayesian posterior probability of the null hypothesis has an explicit interpretation of how strong the data support the null. We make a comparison of the p-value and the posterior probability by considering a recent clinical trial. The results show that even when we reject the null hypothesis, there is still a substantial probability (around 20%) that the null is true. Not only should we examine whether the data would have rarely occurred under the null hypothesis, but we also need to know whether the data would be rare under the alternative. As a result, the p-value only provides one side of the information, for which the Bayes factor and posterior probability may offer complementary evidence. Copyright © 2015 Elsevier Inc. All rights reserved.
A comprehensive approach to evaluating and classifying sun-protective clothing.

PubMed

Downs, N J; Harrison, S L

2018-04-01

National standards for clothing designed to protect the wearer from the harmful effects of solar ultraviolet radiation (UVR) have been implemented in Australia/New Zealand, Europe and the U.S.A. Industry standards reflect the need to protect the skin by covering a considerable proportion of the potentially exposed body surface area (BSA) and by reducing UVR-transmission through fabric (the Ultraviolet Protection Factor; UPF). This research aimed to develop a new index for rating sun-protective clothing that incorporates the BSA coverage of the garment in addition to the UPF of the fabric. A mannequin model was fixed to an optical bench and marked with horizontal lines at 1-cm intervals. An algorithm (the Garment Protector Factor; GPF) was developed based on the number of lines visible on the clothed vs. unclothed mannequin and the UPF of the garment textile. This data was collected in 2015/16 and analysed in 2016. The GPF weights fabric UPF by BSA coverage above the minimum required by international sun-protective clothing standards for upper-body, lower-body and full-body garments. The GPF increases with BSA coverage of the garment and fabric UPF. Three nominal categories are proposed for the GPF: 0 ≤ GPF < 3 for garments that 'meet' minimum standards; 3 ≤ GPF < 6 for garments providing 'good' sun protection; and GPF ≥ 6 indicating 'excellent' protection. Adoption of the proposed rating scheme should encourage manufacturers to design sun-protective garments that exceed the minimum standard for BSA coverage, with positive implications for skin cancer prevention, consumer education and sun-protection awareness. © 2017 British Association of Dermatologists.

Long-term risk analysis associated with nuclear waste disposal in space

NASA Technical Reports Server (NTRS)

Friedlander, A. L.; Davis, D. R.

1979-01-01

An assessment and verification of previous analytic results on the long term risk of earth reentry for hazardous payloads is presented. The two areas were studied: (1) stability of nominal, near-circular storage orbits in the regions between Venus and earth and between earth and Mars, and (2) probability of earth reentry for off-nominal planet-crossing orbits resulting from deployment system failures. In the first area, numerical integrations of the equations of motion are compared with stability predications based on secular perturbation theory. The agreement is good in terms of the heliocentric distances covered and the general behavior of the orbital history, although certain near-resonance situations can lead to difficulty. In the second area, a Monte Carlo simulation of orbital evolution is used and the results compared with Opik's analytic theory of planetary encounters and collision statistics, with data verified to within a close order-of-magnitude.
Covered today, sick tomorrow? Trends and correlates of children's health insurance instability.

PubMed

Hill, Heather D; Shaefer, H Luke

2011-10-01

Many children with health insurance will experience gaps in coverage over time, potentially reducing their access to and use of preventive health care services. This article uses the Survey of Income and Program Participation to examine how the stability of children's health insurance changed between 1990 and 2005 and to identify dynamic aspects of family life associated with transitions in coverage. Children's health insurance instability has increased since the early 1990s, due to greater movement between insured and uninsured states and between private and public insurance coverage. Changes in the employment and marital status of the family head are highly associated with an increased risk of a child losing and gaining public and private coverage, largely in hypothesized directions. The exception is that marital dissolution and job loss are associated with an increased probability of a child losing public insurance, despite there being no clear policy explanation for such a relationship.
Influence of crown class, diameter, and sprout rank on red maple (Acer rubrum L.) development during forest succession in Connecticut

Treesearch

Jeffery S. Ward; George R. Stephens

1993-01-01

Crown class, stem diameter, and sprout rank of 2067 red maples on medium quality sites were measured at 10-yr intervals between 1927-1987. Nominal stand age was 25 yrs in 1927. There was a progressive increase in the probability of an individual red maple ascending into the upper canopy and persisting in the upper canopy from suppressed through dominant crown classes...
An evaluation of the Bayesian approach to fitting the N-mixture model for use with pseudo-replicated count data

USGS Publications Warehouse

Toribo, S.G.; Gray, B.R.; Liang, S.

2011-01-01

The N-mixture model proposed by Royle in 2004 may be used to approximate the abundance and detection probability of animal species in a given region. In 2006, Royle and Dorazio discussed the advantages of using a Bayesian approach in modelling animal abundance and occurrence using a hierarchical N-mixture model. N-mixture models assume replication on sampling sites, an assumption that may be violated when the site is not closed to changes in abundance during the survey period or when nominal replicates are defined spatially. In this paper, we studied the robustness of a Bayesian approach to fitting the N-mixture model for pseudo-replicated count data. Our simulation results showed that the Bayesian estimates for abundance and detection probability are slightly biased when the actual detection probability is small and are sensitive to the presence of extra variability within local sites.
Role of non-traditional locations for seasonal flu vaccination: Empirical evidence and evaluation.

PubMed

Kim, Namhoon; Mountain, Travis P

2017-05-19

This study investigated the role of non-traditional locations in the decision to vaccinate for seasonal flu. We measured individuals' preferred location for seasonal flu vaccination by examining the National H1N1 Flu Survey (NHFS) conducted from late 2009 to early 2010. Our econometric model estimated the probabilities of possible choices by varying individual characteristics, and predicted the way in which the probabilities are expected to change given the specific covariates of interest. From this estimation, we observed that non-traditional locations significantly influenced the vaccination of certain individuals, such as those who are high-income, educated, White, employed, and living in a metropolitan statistical area (MSA), by increasing the coverage. Thus, based on the empirical evidence, our study suggested that supporting non-traditional locations for vaccination could be effective in increasing vaccination coverage. Copyright © 2017 Elsevier Ltd. All rights reserved.
Standardized likelihood ratio test for comparing several log-normal means and confidence interval for the common mean.

PubMed

Krishnamoorthy, K; Oral, Evrim

2017-12-01

Standardized likelihood ratio test (SLRT) for testing the equality of means of several log-normal distributions is proposed. The properties of the SLRT and an available modified likelihood ratio test (MLRT) and a generalized variable (GV) test are evaluated by Monte Carlo simulation and compared. Evaluation studies indicate that the SLRT is accurate even for small samples, whereas the MLRT could be quite liberal for some parameter values, and the GV test is in general conservative and less powerful than the SLRT. Furthermore, a closed-form approximate confidence interval for the common mean of several log-normal distributions is developed using the method of variance estimate recovery, and compared with the generalized confidence interval with respect to coverage probabilities and precision. Simulation studies indicate that the proposed confidence interval is accurate and better than the generalized confidence interval in terms of coverage probabilities. The methods are illustrated using two examples.
The Impact of Exceeding TANF Time Limits on the Access to Healthcare of Low-Income Mothers.

PubMed

Narain, Kimberly; Ettner, Susan

2017-01-01

The objective of this article is to estimate the relationship of exceeding Temporary Assistance for Needy Families (TANF) time limits, with health insurance, healthcare, and health outcomes. The authors use Heckman selection models that exploit variability in state time-limit duration and timing of policy implementation as identifying exclusion restrictions to adjust the effect estimates of exceeding time limits for possible correlations between the probability of exceeding time limits and unobservable factors influencing the outcomes. The authors find that exceeding time limits decreases the predicted probability of Medicaid coverage, increases the predicted probability of being uninsured, and decreases the predicted probability of annual medical provider contact.
Au Nanoparticle Sub-Monolayers Sandwiched between Sol-Gel Oxide Thin Films

PubMed Central

Della Gaspera, Enrico; Menin, Enrico; Sada, Cinzia

2018-01-01

Sub-monolayers of monodisperse Au colloids with different surface coverage have been embedded in between two different metal oxide thin films, combining sol-gel depositions and proper substrates functionalization processes. The synthetized films were TiO2, ZnO, and NiO. X-ray diffraction shows the crystallinity of all the oxides and verifies the nominal surface coverage of Au colloids. The surface plasmon resonance (SPR) of the metal nanoparticles is affected by both bottom and top oxides: in fact, the SPR peak of Au that is sandwiched between two different oxides is centered between the SPR frequencies of Au sub-monolayers covered with only one oxide, suggesting that Au colloids effectively lay in between the two oxide layers. The desired organization of Au nanoparticles and the morphological structure of the prepared multi-layered structures has been confirmed by Rutherford backscattering spectrometry (RBS), Secondary Ion Mass Spectrometry (SIMS), and Scanning Electron Microscopy (SEM) analyses that show a high quality sandwich structure. The multi-layered structures have been also tested as optical gas sensors. PMID:29538338
National Health Spending: Faster Growth In 2015 As Coverage Expands And Utilization Increases.

PubMed

Martin, Anne B; Hartman, Micah; Washington, Benjamin; Catlin, Aaron

2017-01-01

Total nominal US health care spending increased 5.8 percent and reached $3.2 trillion in 2015. On a per person basis, spending on health care increased 5.0 percent, reaching $9,990. The share of gross domestic product devoted to health care spending was 17.8 percent in 2015, up from 17.4 percent in 2014. Coverage expansions that began in 2014 as a result of the Affordable Care Act continued to affect health spending growth in 2015. In that year, the faster growth in total health care spending was primarily due to accelerated growth in spending for private health insurance (growth of 7.2 percent), hospital care (5.6 percent), and physician and clinical services (6.3 percent). Continued strong growth in Medicaid (9.7 percent) and retail prescription drug spending (9.0 percent), albeit at a slower rate than in 2014, contributed to overall health care spending growth in 2015. Project HOPE—The People-to-People Health Foundation, Inc.
National Health Care Spending In 2016: Spending And Enrollment Growth Slow After Initial Coverage Expansions.

PubMed

Hartman, Micah; Martin, Anne B; Espinosa, Nathan; Catlin, Aaron; The National Health Expenditure Accounts Team

2018-01-01

Total nominal US health care spending increased 4.3 percent and reached $3.3 trillion in 2016. Per capita spending on health care increased by $354, reaching $10,348. The share of gross domestic product devoted to health care spending was 17.9 percent in 2016, up from 17.7 percent in 2015. Health spending growth decelerated in 2016 following faster growth in 2014 and 2015 associated with coverage expansions under the Affordable Care Act (ACA) and strong retail prescription drug spending growth. In 2016 the slowdown was broadly based, as spending for the largest categories by payer and by service decelerated. Enrollment trends drove the slowdown in Medicaid and private health insurance spending growth in 2016, while slower per enrollee spending growth influenced Medicare spending. Furthermore, spending for retail prescription drugs slowed, partly as a result of lower spending for drugs used to treat hepatitis C, while slower use and intensity of services drove the slowdown in hospital care and physician and clinical services.
Evaluation of a vaccine passport to improve vaccine coverage in people living with HIV.

PubMed

Chadwick, D R; Corbett, K; Mann, S; Teruzzi, B; Horner, S

2018-01-01

An increased risk of vaccine-preventable infections (VPIs) is seen in people living with HIV (PLWH), and current vaccine coverage and immunity is variable. Vaccine passports have the potential to improve vaccine coverage. The objective was to assess how successful a vaccine passport was in improving vaccine coverage in PLWH. Baseline immunity to VPIs was established in PLWH attending a single HIV clinic and vaccinations required were determined based on the BHIVA Vaccination Guidelines (2015). The passport was completed and the PLWH informed about additional vaccines they should obtain from primary care. After 6-9 months the passport was reviewed including confirmation if vaccines were given. PLWH satisfaction with the system was evaluated by a survey. Seventy-three PLWH provided sufficient data for analysis. At baseline significant proportions of PLWH were not immune/unvaccinated to the main VPIs, especially human papillomavirus, pneumococcus and measles. After the passport was applied immunity improved significantly (56% overall, p < 0.01) for most VPIs; however, full coverage was not achieved. The system was popular with PLWH. The passport was successful in increasing vaccination coverage although full or near-full coverage was not achieved. A more successful service would probably be achieved by commissioning English HIV clinics to provide all vaccines.
Media advocacy, tobacco control policy change and teen smoking in Florida

PubMed Central

Niederdeppe, Jeff; Farrelly, Matthew C; Wenter, Dana

2007-01-01

Objective To assess whether media advocacy activities implemented by the Florida Tobacco Control Program contributed to increased news coverage, policy changes and reductions in youth smoking. Methods A content analysis of news coverage appearing in Florida newspapers between 22 April 1998 and 31 December 2001 was conducted, and patterns of coverage before and after the implementation of media advocacy efforts to promote tobacco product placement ordinances were compared. Event history analysis was used to assess whether news coverage increased the probability of enacting these ordinances in 23 of 67 Florida counties and ordinary least square (OLS) regression was used to gauge the effect of these policies on changes in youth smoking prevalence. Results The volume of programme‐related news coverage decreased after the onset of media advocacy efforts, but the ratio of coverage about Students Working Against Tobacco (the Florida Tobacco Control Program's youth advocacy organisation) relative to other topics increased. News coverage contributed to the passage of tobacco product placement ordinances in Florida counties, but these ordinances did not lead to reduced youth smoking. Conclusion This study adds to the growing literature supporting the use of media advocacy as a tool to change health‐related policies. However, results suggest caution in choosing policy goals that may or may not influence health behaviour. PMID:17297073
Early impact of the Affordable Care Act on health insurance coverage of young adults.

PubMed

Cantor, Joel C; Monheit, Alan C; DeLia, Derek; Lloyd, Kristen

2012-10-01

To evaluate one of the first implemented provisions of the Patient Protection and Affordable Care Act (ACA), which permits young adults up to age 26 to enroll as dependents on a parent's private health plan. Nearly one-in-three young adults lacked coverage before the ACA. STUDY DESIGN, METHODS, AND DATA: Data from the Current Population Survey 2005-2011 are used to estimate linear probability models within a difference-in-differences framework to estimate how the ACA affected coverage of eligible young adults compared to slightly older adults. Multivariate models control for individual characteristics, economic trends, and prior state-dependent coverage laws. This ACA provision led to a rapid and substantial increase in the share of young adults with dependent coverage and a reduction in their uninsured rate in the early months of implementation. Models accounting for prior state dependent expansions suggest greater policy impact in 2010 among young adults who were also eligible under a state law. ACA-dependent coverage expansion represents a rare public policy success in the effort to cover the uninsured. Still, this policy may have later unintended consequences for premiums for alternative forms of coverage and employer-offered rates for young adult workers. © Health Research and Educational Trust.
Early Impact of the Affordable Care Act on Health Insurance Coverage of Young Adults

PubMed Central

Cantor, Joel C; Monheit, Alan C; DeLia, Derek; Lloyd, Kristen

2012-01-01

Research Objective To evaluate one of the first implemented provisions of the Patient Protection and Affordable Care Act (ACA), which permits young adults up to age 26 to enroll as dependents on a parent's private health plan. Nearly one-in-three young adults lacked coverage before the ACA. Study Design, Methods, and Data Data from the Current Population Survey 2005–2011 are used to estimate linear probability models within a difference-in-differences framework to estimate how the ACA affected coverage of eligible young adults compared to slightly older adults. Multivariate models control for individual characteristics, economic trends, and prior state-dependent coverage laws. Principal Findings This ACA provision led to a rapid and substantial increase in the share of young adults with dependent coverage and a reduction in their uninsured rate in the early months of implementation. Models accounting for prior state dependent expansions suggest greater policy impact in 2010 among young adults who were also eligible under a state law. Conclusions and Implications ACA-dependent coverage expansion represents a rare public policy success in the effort to cover the uninsured. Still, this policy may have later unintended consequences for premiums for alternative forms of coverage and employer-offered rates for young adult workers. PMID:22924684
Academic writing in a corpus of 4th grade science notebooks: An analysis of student language use and adult expectations of the genres of school science

NASA Astrophysics Data System (ADS)

Esquinca, Alberto

This is a study of language use in the context of an inquiry-based science curriculum in which conceptual understanding ratings are used split texts into groups of "successful" and "unsuccessful" texts. "Successful" texts could include known features of science language. 420 texts generated by students in 14 classrooms from three school districts, culled from a prior study on the effectiveness of science notebooks to assess understanding, in addition to the aforementioned ratings are the data sources. In science notebooks, students write in the process of learning (here, a unit on electricity). The analytical framework is systemic functional linguistics (Halliday and Matthiessen, 2004; Eggins, 2004), specifically the concepts of genre, register and nominalization. Genre classification involves an analysis of the purpose and register features in the text (Schleppegrell, 2004). The use of features of the scientific academic register, namely the use relational processes and nominalization (Halliday and Martin, 1993), requires transitivity analysis and noun analysis. Transitivity analysis, consisting of the identification of the process type, is conducted on 4737 ranking clauses. A manual count of each noun used in the corpus allows for a typology of nouns. Four school science genres, procedures, procedural recounts reports and explanations, are found. Most texts (85.4%) are factual, and 14.1% are classified as explanations, the analytical genre. Logistic regression analysis indicates that there is no significant probability that the texts classified as explanation are placed in the group of "successful" texts. In addition, material process clauses predominate in the corpus, followed by relational process clauses. Results of a logistic regression analysis indicate that there is a significant probability (Chi square = 15.23, p < .0001) that texts with a high rate of relational processes are placed in the group of "successful" texts. In addition, 59.5% of 6511 nouns are references to physical materials, followed by references to abstract concepts (35.54%). Only two of the concept nouns were found to be nominalized referents in definition model sentences. In sum, the corpus has recognizable genres and features science language, and relational processes are more prevalent in "successful" texts. However, the pervasive feature of science language, nominalization, is scarce.
Coverage and Preventive Screening

PubMed Central

Meeker, Daniella; Joyce, Geoffrey F; Malkin, Jesse; Teutsch, Steven M; Haddix, Anne C; Goldman, Dana P

2011-01-01

Context Preventive care has been shown as a high-value health care service. Many employers now offer expanded coverage of preventive care to encourage utilization. Objective To determine whether expanding coverage is an effective means to encourage utilization. Design Comparison of screening rates before and after introduction of deductible-free coverage. Setting People insured through large corporations between 2002 and 2006. Patients or Other Participants Preferred Provider Organization (PPO) enrollees from an employer introducing deductible-free coverage, and a control group enrolled in a PPO from a second employer with no policy change. Main Outcome Measures Adjusted probability of endoscopy, fecal occult blood test (FOBT), lipid screens, mammography, and Papanicolaou (pap) smears. Intervention Introduction of first-dollar coverage (FDC) of preventive services in 2003. Results After adjusting for demographics and secular trends, there were between 23 and 78 additional uses per 1,000 eligible patients of covered preventive screens (lipid screens, pap smears, mammograms, and FOBT), with no significant changes in the control group or in a service without FDC (endoscopy). Conclusions FDC improves utilization modestly among healthy individuals, particularly those in lower deductible plans. Compliance with guidelines can be encouraged by lowering out-of-pocket costs, but patients' predisposing characteristics merit attention. PMID:21029084
Mass Movement and Landform Degradation on the Icy Galilean Satellites: Results of the Galileo Nominal Mission

NASA Technical Reports Server (NTRS)

Moore, Jeffrey M.; Asphaug, Erik; Morrison, David; Spencer, John R.; Chapman, Clark R.; Bierhaus, Beau; Sullivan, Robert J.; Chuang, Frank C.; Klemaszewski, James E.; Greeley, Ronald

1999-01-01

The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on the icy Galilean satellites of Jupiter. Weakening of surface materials coupled with mass movement reduces the topographic relief of landforms by moving surface materials down-slope. Throughout the Galileo orbiter nominal mission we have studied all known forms of mass movement and landform degradation of the icy galilean satellites, of which Callisto, by far, displays the most degraded surface. Callisto exhibits discrete mass movements that are larger and apparently more common than seen elsewhere. Most degradation on Ganymede appears consistent with sliding or slumping, impact erosion, and regolith evolution. Sliding or slumping is also observed at very small (100 m) scale on Europa. Sputter ablation, while probably playing some role in the evolution of Ganymede's and Callisto's debris layers, appears to be less important than other processes. Sputter ablation might play a significant role on Europa only if that satellite's surface is significantly older than 10(exp 8) years, far older than crater statistics indicate. Impact erosion and regolith formation on Europa are probably minimal, as implied by the low density of small craters there. Impact erosion and regolith formation may be important on the dark terrains of Ganymede, though some surfaces on this satellite may be modified by sublimation-degradation. While impact erosion and regolith formation are expected to operate with the same vigor on Callisto as on Ganymede, most of the areas examined at high resolution on Callisto have an appearance that implies that some additional process is at work, most likely sublimation-driven landform modification and mass wasting. The extent of surface degradation ascribed to sublimation on the outer two Galilean satellites implies that an ice more volatile than H2O is probably involved.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Williamson, Casey W.; Green, Garrett; Noticewala, Sonal S.

Purpose: Validated models are needed to justify strategies to define planning target volumes (PTVs) for intact cervical cancer used in clinical practice. Our objective was to independently validate a previously published shape model, using data collected prospectively from clinical trials. Methods and Materials: We analyzed 42 patients with intact cervical cancer treated with daily fractionated pelvic intensity modulated radiation therapy and concurrent chemotherapy in one of 2 prospective clinical trials. We collected online cone beam computed tomography (CBCT) scans before each fraction. Clinical target volume (CTV) structures from the planning computed tomography scan were cast onto each CBCT scan aftermore » rigid registration and manually redrawn to account for organ motion and deformation. We applied the 95% isodose cloud from the planning computed tomography scan to each CBCT scan and computed any CTV outside the 95% isodose cloud. The primary aim was to determine the proportion of CTVs that were encompassed within the 95% isodose volume. A 1-sample t test was used to test the hypothesis that the probability of complete coverage was different from 95%. We used mixed-effects logistic regression to assess effects of time and patient variability. Results: The 95% isodose line completely encompassed 92.3% of all CTVs (95% confidence interval, 88.3%-96.4%), not significantly different from the 95% probability anticipated a priori (P=.19). The overall proportion of missed CTVs was small: the grand mean of covered CTVs was 99.9%, and 95.2% of misses were located in the anterior body of the uterus. Time did not affect coverage probability (P=.71). Conclusions: With the clinical implementation of a previously proposed PTV definition strategy based on a shape model for intact cervical cancer, the probability of CTV coverage was high and the volume of CTV missed was low. This PTV expansion strategy is acceptable for clinical trials and practice; however, we recommend daily image guidance to avoid systematic large misses in select patients.« less
Cost-Effectiveness Analysis of Screening for and Managing Identified Hypertension for Cardiovascular Disease Prevention in Vietnam

PubMed Central

Nguyen, Thi-Phuong-Lan; Wright, E. Pamela; Nguyen, Thanh-Trung; Schuiling-Veninga, C. C. M.; Bijlsma, M. J.; Nguyen, Thi-Bach-Yen; Postma, M. J.

2016-01-01

Objective To inform development of guidelines for hypertension management in Vietnam, we evaluated the cost-effectiveness of different strategies on screening for hypertension in preventing cardiovascular disease (CVD). Methods A decision tree was combined with a Markov model to measure incremental cost-effectiveness of different approaches to hypertension screening. Values used as input parameters for the model were taken from different sources. Various screening intervals (one-off, annually, biannually) and starting ages to screen (35, 45 or 55 years) and coverage of treatment were analysed. We ran both a ten-year and a lifetime horizon. Input parameters for the models were extracted from local and regional data. Probabilistic sensitivity analysis was used to evaluate parameter uncertainty. A threshold of three times GDP per capita was applied. Results Cost per quality adjusted life year (QALY) gained varied in different screening scenarios. In a ten-year horizon, the cost-effectiveness of screening for hypertension ranged from cost saving to Int$ 758,695 per QALY gained. For screening of men starting at 55 years, all screening scenarios gave a high probability of being cost-effective. For screening of females starting at 55 years, the probability of favourable cost-effectiveness was 90% with one-off screening. In a lifetime horizon, cost per QALY gained was lower than the threshold of Int$ 15,883 in all screening scenarios among males. Similar results were found in females when starting screening at 55 years. Starting screening in females at 45 years had a high probability of being cost-effective if screening biannually was combined with increasing coverage of treatment by 20% or even if sole biannual screening was considered. Conclusion From a health economic perspective, integrating screening for hypertension into routine medical examination and related coverage by health insurance could be recommended. Screening for hypertension has a high probability of being cost-effective in preventing CVD. An adequate screening strategy can best be selected based on age, sex and screening interval. PMID:27192051
Trends in, and projections of, indicators of universal health coverage in Bangladesh, 1995-2030: a Bayesian analysis of population-based household data.

PubMed

Rahman, Md Shafiur; Rahman, Md Mizanur; Gilmour, Stuart; Swe, Khin Thet; Krull Abe, Sarah; Shibuya, Kenji

2018-01-01

Many countries are implementing health system reforms to achieve universal health coverage (UHC) by 2030. To understand the progress towards UHC in Bangladesh, we estimated trends in indicators of the health service and of financial risk protection. We also estimated the probability of Bangladesh's achieving of UHC targets of 80% essential health-service coverage and 100% financial risk protection by 2030. We estimated the coverage of UHC indicators-13 prevention indicators and four treatment indicators-from 19 nationally representative population-based household surveys done in Bangladesh from Jan 1, 1991, to Dec 31, 2014. We used a Bayesian regression model to estimate the trend and to predict the coverage of UHC indicators along with the probabilities of achieving UHC targets of 80% coverage of health services and 100% coverage of financial risk protection from catastrophic and impoverishing health payments by 2030. We used the concentration index and relative index of inequality to assess wealth-based inequality in UHC indicators. If the current trends remain unchanged, we estimated that coverage of childhood vaccinations, improved water, oral rehydration treatment, satisfaction with family planning, and non-use of tobacco will achieve the 80% target by 2030. However, coverage of four antenatal care visits, facility-based delivery, skilled birth attendance, postnatal checkups, care seeking for pneumonia, exclusive breastfeeding, non-overweight, and adequate sanitation were not projected to achieve the target. Quintile-specific projections showed wide wealth-based inequality in access to antenatal care, postnatal care, delivery care, adequate sanitation, and care seeking for pneumonia, and this inequality was projected to continue for all indicators. The incidence of catastrophic health expenditure and impoverishment were projected to increase from 17% and 4%, respectively, in 2015, to 20% and 9%, respectively, by 2030. Inequality analysis suggested that wealthiest households would disproportionately face more financial catastrophe than the most disadvantaged households. Despite progress, Bangladesh will not achieve the 2030 UHC targets unless the country scales up interventions related to maternal and child health services, and reforms health financing systems to avoid high dependency on out-of-pocket payments. The introduction of a national health insurance system, increased public funding for health care, and expansion of community-based clinics in rural areas could help to move the country towards UHC. Japan Ministry of Health, Labour, and Welfare. Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.

2016 Mars Insight Mission Design and Navigation

NASA Technical Reports Server (NTRS)

Abilleira, Fernando; Frauenholz, Ray; Fujii, Ken; Wallace, Mark; You, Tung-Han

2014-01-01

Scheduled for a launch in the 2016 Earth to Mars opportunity, the Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) Mission will arrive to Mars in late September 2016 with the primary objective of placing a science lander on the surface of the Red Planet followed by the deployment of two science instruments to investigate the fundamental processes of terrestrial planet formation and evolution. In order to achieve a successful landing, the InSight Project has selected a launch/arrival strategy that satisfies the following key and driving requirements: (1) Deliver a total launch mass of 727 kg, (2) target a nominal landing site with a cumulative Delta V99 less than 30 m/s, and (3) approach EDL with a V-infinity upper limit of 3.941 km/s and (4) an entry flight-path angle (EFPA) of -12.5 +/- 0.26 deg, 3-sigma; the InSight trajectories have been designed such that they (5) provide UHF-band communications via Direct-To-Earth and MRO from Entry through landing plus 60 s, (6) with injection aimpoints biased away from Mars such that the probability of the launch vehicle upper stage impacting Mars is less than 1.0 X 10(exp 4) for fifty years after launch, and (7) non-nominal impact probabilities due to failure during the Cruise phase less than 1.0 X 10(exp 2).
Theoretical aspects of studies of high coverage oxidation of the Cu(100) surface using low energy positrons

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Maddox, W. B.

2010-10-01

The study of adsorption of oxygen on transition metal surface is important for the understanding of oxidation, heterogeneous catalysis, and metal corrosion. The structures formed on transition metal surfaces vary from simple adlayers of chemisorbed oxygen to oxygen diffusion into the sub-surface region and the formation of oxides. In this work we present the results of an ab-initio investigation of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the oxidized Cu(100) surface under conditions of high oxygen coverage. Calculations are performed for various high coverage missing row structures ranging between 0.50 and 1.50 ML oxygen coverage. Calculations are also performed for the on-surface adsorption of oxygen on the unreconstructed Cu(001) surface for coverages up to one monolayer to use for comparison. The geometry of the surfaces with adsorbed oxygen is fully optimized. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy.
Impact of Alternative Medical Device Approval Processes on Costs and Health

PubMed Central

George, Benjamin P.; Venkataraman, Vinayak; Dorsey, E. Ray

2014-01-01

Background Medical devices are often introduced prior to randomized‐trial evidence of efficacy and this slows completion of trials. Alternative regulatory approaches include restricting device use outside of trials prior to trial evidence of efficacy (like the drug approval process) or restricting out‐of‐trial use but permitting coverage within trials such as Medicare's Coverage with Study Participation (CSP). Methods We compared the financial impact to manufacturers and insurers of three regulatory alternatives: (1) limited regulation (current approach), (2) CSP, and (3) restrictive regulation (like the current drug approval process). Using data for patent foramen ovale closure devices, we modeled key parameters including recruitment time, probability of device efficacy, market adoption, and device cost/price to calculate profits to manufacturers, costs to insurers, and overall societal impact on health. Results For manufacturers, profits were greatest under CSP—driven by faster market adoption of effective devices—followed by restrictive regulation. Societal health benefit in total quality‐adjusted life years was greatest under CSP. Insurers’ expenditures for ineffective devices were greatest with limited regulation. Findings were robust over a reasonable range of probabilities of trial success. Conclusions Regulation restricting out‐of‐trial device use and extending limited insurance coverage to clinical trial participants may balance manufacturer and societal interests. PMID:25185975
Gathering opinion leader data for a tailored implementation intervention in secondary healthcare: a randomised trial.

PubMed

Farley, Katherine; Hanbury, Andria; Thompson, Carl

2014-03-10

Health professionals' behaviour is a key component in compliance with evidence-based recommendations. Opinion leaders are an oft-used method of influencing such behaviours in implementation studies, but reliably and cost effectively identifying them is not straightforward. Survey and questionnaire based data collection methods have potential and carefully chosen items can - in theory - both aid identification of opinion leaders and help in the design of an implementation strategy itself. This study compares two methods of identifying opinion leaders for behaviour-change interventions. Healthcare professionals working in a single UK mental health NHS Foundation Trust were randomly allocated to one of two questionnaires. The first, slightly longer questionnaire, asked for multiple nominations of opinion leaders, with specific information about the nature of the relationship with each nominee. The second, shorter version, asked simply for a list of named "champions" but no more additional information. We compared, using Chi Square statistics, both the questionnaire response rates and the number of health professionals likely to be influenced by the opinion leaders (i.e. the "coverage" rates) for both questionnaire conditions. Both questionnaire versions had low response rates: only 15% of health professionals named colleagues in the longer questionnaire and 13% in the shorter version. The opinion leaders identified by both methods had a low number of contacts (range of coverage, 2-6 each). There were no significant differences in response rates or coverage between the two identification methods. The low response and population coverage rates for both questionnaire versions suggest that alternative methods of identifying opinion leaders for implementation studies may be more effective. Future research should seek to identify and evaluate alternative, non-questionnaire based, methods of identifying opinion leaders in order to maximise their potential in organisational behaviour change interventions.
Developing appropriate methods for cost-effectiveness analysis of cluster randomized trials.

PubMed

Gomes, Manuel; Ng, Edmond S-W; Grieve, Richard; Nixon, Richard; Carpenter, James; Thompson, Simon G

2012-01-01

Cost-effectiveness analyses (CEAs) may use data from cluster randomized trials (CRTs), where the unit of randomization is the cluster, not the individual. However, most studies use analytical methods that ignore clustering. This article compares alternative statistical methods for accommodating clustering in CEAs of CRTs. Our simulation study compared the performance of statistical methods for CEAs of CRTs with 2 treatment arms. The study considered a method that ignored clustering--seemingly unrelated regression (SUR) without a robust standard error (SE)--and 4 methods that recognized clustering--SUR and generalized estimating equations (GEEs), both with robust SE, a "2-stage" nonparametric bootstrap (TSB) with shrinkage correction, and a multilevel model (MLM). The base case assumed CRTs with moderate numbers of balanced clusters (20 per arm) and normally distributed costs. Other scenarios included CRTs with few clusters, imbalanced cluster sizes, and skewed costs. Performance was reported as bias, root mean squared error (rMSE), and confidence interval (CI) coverage for estimating incremental net benefits (INBs). We also compared the methods in a case study. Each method reported low levels of bias. Without the robust SE, SUR gave poor CI coverage (base case: 0.89 v. nominal level: 0.95). The MLM and TSB performed well in each scenario (CI coverage, 0.92-0.95). With few clusters, the GEE and SUR (with robust SE) had coverage below 0.90. In the case study, the mean INBs were similar across all methods, but ignoring clustering underestimated statistical uncertainty and the value of further research. MLMs and the TSB are appropriate analytical methods for CEAs of CRTs with the characteristics described. SUR and GEE are not recommended for studies with few clusters.
Developing Appropriate Methods for Cost-Effectiveness Analysis of Cluster Randomized Trials

PubMed Central

Gomes, Manuel; Ng, Edmond S.-W.; Nixon, Richard; Carpenter, James; Thompson, Simon G.

2012-01-01

Aim. Cost-effectiveness analyses (CEAs) may use data from cluster randomized trials (CRTs), where the unit of randomization is the cluster, not the individual. However, most studies use analytical methods that ignore clustering. This article compares alternative statistical methods for accommodating clustering in CEAs of CRTs. Methods. Our simulation study compared the performance of statistical methods for CEAs of CRTs with 2 treatment arms. The study considered a method that ignored clustering—seemingly unrelated regression (SUR) without a robust standard error (SE)—and 4 methods that recognized clustering—SUR and generalized estimating equations (GEEs), both with robust SE, a “2-stage” nonparametric bootstrap (TSB) with shrinkage correction, and a multilevel model (MLM). The base case assumed CRTs with moderate numbers of balanced clusters (20 per arm) and normally distributed costs. Other scenarios included CRTs with few clusters, imbalanced cluster sizes, and skewed costs. Performance was reported as bias, root mean squared error (rMSE), and confidence interval (CI) coverage for estimating incremental net benefits (INBs). We also compared the methods in a case study. Results. Each method reported low levels of bias. Without the robust SE, SUR gave poor CI coverage (base case: 0.89 v. nominal level: 0.95). The MLM and TSB performed well in each scenario (CI coverage, 0.92–0.95). With few clusters, the GEE and SUR (with robust SE) had coverage below 0.90. In the case study, the mean INBs were similar across all methods, but ignoring clustering underestimated statistical uncertainty and the value of further research. Conclusions. MLMs and the TSB are appropriate analytical methods for CEAs of CRTs with the characteristics described. SUR and GEE are not recommended for studies with few clusters. PMID:22016450
Increasing the coverage area through relay node deployment in long term evolution advanced cellular networks

NASA Astrophysics Data System (ADS)

Aldhaibani, Jaafar A.; Ahmad, R. B.; Yahya, A.; Azeez, Suzan A.

2015-05-01

Wireless multi-hop relay networks have become very important technologies in mobile communications. These networks ensure high throughput and coverage extension with a low cost. The poor capacity at cell edges is not enough to meet with growing demand of high capacity and throughput irrespective of user's placement in the cellular network. In this paper we propose optimal placement of relay node that provides maximum achievable rate at users and enhances the throughput and coverage at cell edge region. The proposed scheme is based on the outage probability at users and taken on account the interference between nodes. Numerical analyses along with simulation results indicated there are an improvement in capacity for users at the cell edge is 40% increment from all cell capacity.
Adlayer structure dependent ultrafast desorption dynamics in carbon monoxide adsorbed on Pd (111)

NASA Astrophysics Data System (ADS)

Hong, Sung-Young; Xu, Pan; Camillone, Nina R.; White, Michael G.; Camillone, Nicholas

2016-07-01

We report our ultrafast photoinduced desorption investigation of the coverage dependence of substrate-adsorbate energy transfer in carbon monoxide adlayers on the (111) surface of palladium. As the CO coverage is increased, the adsorption site population shifts from all threefold hollows (up to 0.33 ML), to bridge and near bridge (>0.5 to 0.6 ML) and finally to mixed threefold hollow plus top site (at saturation at 0.75 ML). We show that between 0.24 and 0.75 ML this progression of binding site motifs is accompanied by two remarkable features in the ultrafast photoinduced desorption of the adsorbates: (i) the desorption probability increases roughly two orders magnitude, and (ii) the adsorbate-substrate energy transfer rate observed in two-pulse correlation experiments varies nonmonotonically, having a minimum at intermediate coverages. Simulations using a phenomenological model to describe the adsorbate-substrate energy transfer in terms of frictional coupling indicate that these features are consistent with an adsorption-site dependent electron-mediated energy coupling strength, ηel, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of ηel largely counterbalances the decrease in the desorption activation energy that accompanies this progression of adsorption site motifs, moderating what would otherwise be a rise of several orders of magnitude in the desorption probability. Within this framework, the observed energy transfer rate enhancement at saturation coverage is due to interadsorbate energy transfer from the copopulation of molecules bound in three-fold hollows to their top-site neighbors.
Adlayer structure dependent ultrafast desorption dynamics in carbon monoxide adsorbed on Pd (111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Sung-Young; Camillone, Nina R.; Camillone, Nicholas, E-mail: nicholas@bnl.gov

We report our ultrafast photoinduced desorption investigation of the coverage dependence of substrate–adsorbate energy transfer in carbon monoxide adlayers on the (111) surface of palladium. As the CO coverage is increased, the adsorption site population shifts from all threefold hollows (up to 0.33 ML), to bridge and near bridge (>0.5 to 0.6 ML) and finally to mixed threefold hollow plus top site (at saturation at 0.75 ML). We show that between 0.24 and 0.75 ML this progression of binding site motifs is accompanied by two remarkable features in the ultrafast photoinduced desorption of the adsorbates: (i) the desorption probability increasesmore » roughly two orders magnitude, and (ii) the adsorbate–substrate energy transfer rate observed in two-pulse correlation experiments varies nonmonotonically, having a minimum at intermediate coverages. Simulations using a phenomenological model to describe the adsorbate–substrate energy transfer in terms of frictional coupling indicate that these features are consistent with an adsorption-site dependent electron-mediated energy coupling strength, η{sub el}, that decreases with binding site in the order: three-fold hollow > bridge and near bridge > top site. This weakening of η{sub el} largely counterbalances the decrease in the desorption activation energy that accompanies this progression of adsorption site motifs, moderating what would otherwise be a rise of several orders of magnitude in the desorption probability. Within this framework, the observed energy transfer rate enhancement at saturation coverage is due to interadsorbate energy transfer from the copopulation of molecules bound in three-fold hollows to their top-site neighbors.« less
Medicaid Coverage of Methadone Maintenance and the Use of Opioid Agonist Therapy Among Pregnant Women in Specialty Treatment.

PubMed

Bachhuber, Marcus A; Mehta, Pooja K; Faherty, Laura J; Saloner, Brendan

2017-12-01

Opioid agonist therapy (OAT) is the standard of care for pregnant women with opioid use disorder (OUD). Medicaid coverage policies may strongly influence OAT use in this group. To examine the association between Medicaid coverage of methadone maintenance and planned use of OAT in the publicly funded treatment system. Retrospective cross-sectional analysis of treatment admissions in 30 states extracted from the Treatment Episode Data Set (2013 and 2014). Medicaid-insured pregnant women with OUD (n=3354 treatment admissions). The main outcome measure was planned use of OAT on admission. The main exposure was state Medicaid coverage of methadone maintenance. Using multivariable logistic regression models adjusting for sociodemographic, substance use, and treatment characteristics, we compared the probability of planned OAT use in states with Medicaid coverage of methadone maintenance versus states without coverage. A total of 71% of pregnant women admitted to OUD treatment were 18-29 years old, 85% were white non-Hispanic, and 56% used heroin. Overall, 74% of admissions occurred in the 18 states with Medicaid coverage of methadone maintenance and 53% of admissions involved planned use of OAT. Compared with states without Medicaid coverage of methadone maintenance, admissions in states with coverage were significantly more likely to involve planned OAT use (adjusted difference: 32.9 percentage points, 95% confidence interval, 19.2-46.7). Including methadone maintenance in the Medicaid benefit is essential to increasing OAT among pregnant women with OUD and should be considered a key policy strategy to enhance outcomes for mothers and newborns.
Employee responses to health insurance premium increases.

PubMed

Goldman, Dana P; Leibowitz, Arleen A; Robalino, David A

2004-01-01

To determine the sensitivity of employees' health insurance decisions--including the decision to not choose health maintenance organization or fee-for-service coverage--during periods of rapidly escalating healthcare costs. A retrospective cohort study of employee plan choices at a single large firm with a "cafeteria-style" benefits plan wherein employees paid all the additional cost of purchasing more generous insurance. We modeled the probability that an employee would drop coverage or switch plans in response to employee premium increases using data from a single large US company with employees across 47 states during the 3-year period of 1989 through 1991, a time of large premium increases within and across plans. Premium increases induced substantial plan switching. Single employees were more likely to respond to premium increases by dropping coverage, whereas families tended to switch to another plan. Premium increases of 10% induced 7% of single employees to drop or severely cut back on coverage; 13% to switch to another plan; and 80% to remain in their existing plan. Similar figures for those with family coverage were 11%, 12%, and 77%, respectively. Simulation results that control for known covariates show similar increases. When faced with a dramatic increase in premiums--on the order of 20%--nearly one fifth of the single employees dropped coverage compared with 10% of those with family coverage. Employee coverage decisions are sensitive to rapidly increasing premiums, and single employees may be likely to drop coverage. This finding suggests that sustained premium increases could induce substantial increases in the number of uninsured individuals.
The web and public confidence in MMR vaccination in Italy.

PubMed

Aquino, Francesco; Donzelli, Gabriele; De Franco, Emanuela; Privitera, Gaetano; Lopalco, Pier Luigi; Carducci, Annalaura

2017-08-16

Measles, mumps and rubella (MMR) vaccination coverage in Italy has been decreasing starting from 2012 and, at the present, none of the Italian regions has achieved the goal of 95% coverage target. A decision of the Court of Justice of Rimini in March 2012 that awarded vaccine-injury compensation for a case of autism has been indicated as a probable trigger event leading to a reduction of vaccine confidence in Italy. The aim of the study was to explore the relationship between MMR vaccination coverage to online search trends and social network activity on the topic "autism and MMR vaccine", during the period 2010-2015. A significant inverse correlation was found between MMR vaccination coverage and Internet search activity, tweets and Facebook posts. New media might have played a role in spreading misinformation. Media monitoring could be useful to assess the level of vaccine hesitancy and to plan and target effective information campaigns. Copyright © 2017 Elsevier Ltd. All rights reserved.
Take-up of public insurance and crowd-out of private insurance under recent CHIP expansions to higher income children.

PubMed

Gresenz, Carole Roan; Edgington, Sarah E; Laugesen, Miriam; Escarce, José J

2012-10-01

To analyze the effects of states' expansions of Children's Health Insurance Program (CHIP) eligibility to children in higher income families on health insurance coverage outcomes. 2002-2009 Current Population Survey linked to multiple secondary data sources. Instrumental variables estimation of linear probability models. Outcomes are whether the child had any public insurance, any private insurance, or no insurance coverage during the year. Among children in families with incomes between two and four times the federal poverty line (FPL), four enrolled in CHIP for every 100 who became eligible. Roughly half of the newly eligible children who took up public insurance were previously uninsured. The upper bound "crowd-out" rate was estimated to be 46 percent. The CHIP expansions to children in higher income families were associated with limited uptake of public coverage. Our results additionally suggest that there was crowd-out of private insurance coverage. © Health Research and Educational Trust.
Launch Collision Probability

NASA Technical Reports Server (NTRS)

Bollenbacher, Gary; Guptill, James D.

1999-01-01

This report analyzes the probability of a launch vehicle colliding with one of the nearly 10,000 tracked objects orbiting the Earth, given that an object on a near-collision course with the launch vehicle has been identified. Knowledge of the probability of collision throughout the launch window can be used to avoid launching at times when the probability of collision is unacceptably high. The analysis in this report assumes that the positions of the orbiting objects and the launch vehicle can be predicted as a function of time and therefore that any tracked object which comes close to the launch vehicle can be identified. The analysis further assumes that the position uncertainty of the launch vehicle and the approaching space object can be described with position covariance matrices. With these and some additional simplifying assumptions, a closed-form solution is developed using two approaches. The solution shows that the probability of collision is a function of position uncertainties, the size of the two potentially colliding objects, and the nominal separation distance at the point of closest approach. ne impact of the simplifying assumptions on the accuracy of the final result is assessed and the application of the results to the Cassini mission, launched in October 1997, is described. Other factors that affect the probability of collision are also discussed. Finally, the report offers alternative approaches that can be used to evaluate the probability of collision.
Advanced LPI (Low-Probability-of-Intercept) Intercept Detector Research

DTIC Science & Technology

1985-11-13

following comparisons, we select a nominal loss figure of - 1.5 dB. We note that the above losses pertain to a rectangular BPF ; other filter ships will...this brief expose on the useful properties of the LLR moment- * generating functions, we can now prove the BPF theorem in a rather compact fashion...can be performed following guidelines similar to those in Appendix C, as follows: Let the bandpass AWGN n(t) be represented by 0) n(t) -T2 nj (t) cos
How would mental health parity affect the marginal price of care?

PubMed Central

Zuvekas, S H; Banthin, J S; Selden, T M

2001-01-01

OBJECTIVE: To determine the impact of parity in mental health benefits on the marginal prices that consumers face for mental health treatment. DATA SOURCES/DATA COLLECTION: We used detailed information on health plan benefits for a nationally representative sample of the privately insured population under age 65 taken from the 1987 National Medical Expenditure Survey (Edwards and Berlin 1989). The survey was carefully aged and reweighted to represent 1995 population and coverage characteristics. STUDY DESIGN: We computed marginal out-of-pocket costs from the cost-sharing benefits described by policy booklets under current coverage and under parity for various mental health treatment expenditure levels using the MEDSIM health care microsimulation model developed by researchers at the Agency for Healthcare Research and Quality. Descriptive analyses and two-limit Tobit regression models are used to examine how insurance generosity varies across individuals by demographic and socioeconomic characteristics. Our analyses are limited to a description of how parity would change the marginal incentives faced by consumers under their existing plan's cost-sharing arrangements for mental and physical health care. We do not attempt to simulate how parity might affect the level of benefits, including whether benefits are offered at all, or the level of managed care that affects the actual benefits that plan members receive. Rather, we focus only on the nominal benefits described in their policy booklets. PRINCIPAL FINDINGS: Our results show that as of 1995 parity coverage would substantially reduce the share of mental health expenditures that consumers would pay at the margin under their existing plan's cost-sharing provisions, with larger changes for outpatient care than for inpatient care. Because current mental health coverage generally becomes less generous as expenditures rise, while coverage for other medical care becomes more generous (due to stop-loss provisions), the difference in incentives between current mental health coverage and the assumed parity coverage widens as total expenditure grows. We also find that the impact of parity on marginal incentives would vary greatly across the privately insured population. CONCLUSIONS: Based on the large variation in the impact of parity on marginal incentives across the population under current plan cost-sharing arrangements, changes in the demand for mental health treatment will likely also vary across the population. PMID:11221816
Patient Protection and Affordable Care Act Medicaid expansion and gains in health insurance coverage and access among cancer survivors.

PubMed

Nikpay, Sayeh S; Tebbs, Margaret G; Castellanos, Emily H

2018-04-17

The Patient Protection and Affordable Care Act extends Medicaid coverage to millions of low-income adults, including many survivors of cancer who were unable to purchase affordable health insurance coverage in the individual health insurance market. Using data from the 2011 to 2015 Behavioral Risk Factor Surveillance System, the authors compared changes in coverage and health care access measures for low-income cancer survivors in states that did and did not expand Medicaid. The study population of 17,381 individuals included adults aged 18 to 64 years, and was predominantly female, white, and unmarried. The authors found a relative reduction in the uninsured rate of 11.7 percentage points and a relative increase in the probability of having a personal physician of 5.8 percentage points. Stratifying by whether states expanded Medicaid by 2015, the authors found that relative gains in coverage and access were larger among those individuals residing in states with expanded Medicaid compared with those residing in nonexpansion states. The results of the current study suggest that the Patient Protection and Affordable Care Act Medicaid expansion has improved coverage and access for cancer survivors. Cancer 2018. © 2018 American Cancer Society. © 2018 American Cancer Society.
Failure probability under parameter uncertainty.

PubMed

Gerrard, R; Tsanakas, A

2011-05-01

In many problems of risk analysis, failure is equivalent to the event of a random risk factor exceeding a given threshold. Failure probabilities can be controlled if a decisionmaker is able to set the threshold at an appropriate level. This abstract situation applies, for example, to environmental risks with infrastructure controls; to supply chain risks with inventory controls; and to insurance solvency risks with capital controls. However, uncertainty around the distribution of the risk factor implies that parameter error will be present and the measures taken to control failure probabilities may not be effective. We show that parameter uncertainty increases the probability (understood as expected frequency) of failures. For a large class of loss distributions, arising from increasing transformations of location-scale families (including the log-normal, Weibull, and Pareto distributions), the article shows that failure probabilities can be exactly calculated, as they are independent of the true (but unknown) parameters. Hence it is possible to obtain an explicit measure of the effect of parameter uncertainty on failure probability. Failure probability can be controlled in two different ways: (1) by reducing the nominal required failure probability, depending on the size of the available data set, and (2) by modifying of the distribution itself that is used to calculate the risk control. Approach (1) corresponds to a frequentist/regulatory view of probability, while approach (2) is consistent with a Bayesian/personalistic view. We furthermore show that the two approaches are consistent in achieving the required failure probability. Finally, we briefly discuss the effects of data pooling and its systemic risk implications. © 2010 Society for Risk Analysis.
States With Medically Needy Pathways: Differences in Long-Term and Temporary Medicaid Entry for Low-Income Medicare Beneficiaries.

PubMed

Keohane, Laura M; Trivedi, Amal; Mor, Vincent

2017-10-01

Medically needy pathways may provide temporary catastrophic coverage for low-income Medicare beneficiaries who do not otherwise qualify for full Medicaid benefits. Between January 2009 and June 2010, states with medically needy pathways had a higher percentage of low-income beneficiaries join Medicaid than states without such programs (7.5% vs. 4.1%, p < .01). However, among new full Medicaid participants, living in a state with a medically needy pathway was associated with a 3.8 percentage point (adjusted 95% confidence interval [1.8, 5.8]) increase in the probability of switching to partial Medicaid and a 4.5 percentage point (adjusted 95% confidence interval [2.9, 6.2]) increase in the probability of exiting Medicaid within 12 months. The predicted risk of leaving Medicaid was greatest when new Medicaid participants used only hospital services, rather than nursing home services, in their first month of Medicaid benefits. Alternative strategies for protecting low-income Medicare beneficiaries' access to care could provide more stable coverage.
Cost-effectiveness of 64-slice CT angiography compared to conventional coronary angiography based on a coverage with evidence development study in Ontario.

PubMed

Goeree, Ron; Blackhouse, Gord; Bowen, James M; O'Reilly, Daria; Sutherland, Simone; Hopkins, Robert; Chow, Benjamin; Freeman, Michael; Provost, Yves; Dennie, Carole; Cohen, Eric; Marcuzzi, Dan; Iwanochko, Robert; Moody, Alan; Paul, Narinder; Parker, John D

2013-10-01

Conventional coronary angiography (CCA) is the standard diagnostic for coronary artery disease (CAD), but multi-detector computed tomography coronary angiography (CTCA) is a non-invasive alternative. A multi-center coverage with evidence development study was undertaken and combined with an economic model to estimate the cost-effectiveness of CTCA followed by CCA vs CCA alone. Alternative assumptions were tested in patient scenario and sensitivity analyses. CCA was found to dominate CTCA, however, CTCA was relatively more cost-effective in females, in advancing age, in patients with lower pre-test probabilities of CAD, the higher the sensitivity of CTCA and the lower the probability of undergoing a confirmatory CCA following a positive CTCA. RESULTS were very sensitive to alternative patient populations and modeling assumptions. Careful consideration of patient characteristics, procedures to improve the diagnostic yield of CTCA and selective use of CCA following CTCA will impact whether CTCA is cost-effective or dominates CCA.

Do medical out-of-pocket expenses thrust families into poverty?

PubMed

O'Hara, Brett

2004-02-01

This paper estimates the impact of medical out-of-pocket expenses on families' well-being using the Survey of Income and Program Participation. Medical out-of-pocket expenses include the out-of-pocket costs from medical services and the family's share of health insurance premiums. Demographic characteristics, insurance status, and medical usage of the family are analyzed to determine which characteristics are most likely to impoverish a family. Families impoverished because of medical out-of-pocket expenses are far more likely to have older heads of the family, at least one family member in poor health, or some adults without health insurance. Families without at least one person who worked full time for the entire year were also likely to be impoverished. However, children in the family had little effect on the probability that the family became impoverished. This odd result is probably due to the high correlation between parental health insurance coverage and the health insurance coverage of their children.
Welfare reform, labor supply, and health insurance in the immigrant population.

PubMed

Borjas, George J

2003-11-01

Although the 1996 welfare reform legislation limited the eligibility of immigrant households to receive assistance, many states chose to protect their immigrant populations by offering state-funded aid to these groups. I exploit these changes in eligibility rules to examine the link between the welfare cutbacks and health insurance coverage in the immigrant population. The data reveal that the cutbacks in the Medicaid program did not reduce health insurance coverage rates among targeted immigrants. The immigrants responded by increasing their labor supply, thereby raising the probability of being covered by employer-sponsored health insurance.
Simultaneous use of mark-recapture and radiotelemetry to estimate survival, movement, and capture rates

USGS Publications Warehouse

Powell, L.A.; Conroy, M.J.; Hines, J.E.; Nichols, J.D.; Krementz, D.G.

2000-01-01

Biologists often estimate separate survival and movement rates from radio-telemetry and mark-recapture data from the same study population. We describe a method for combining these data types in a single model to obtain joint, potentially less biased estimates of survival and movement that use all available data. We furnish an example using wood thrushes (Hylocichla mustelina) captured at the Piedmont National Wildlife Refuge in central Georgia in 1996. The model structure allows estimation of survival and capture probabilities, as well as estimation of movements away from and into the study area. In addition, the model structure provides many possibilities for hypothesis testing. Using the combined model structure, we estimated that wood thrush weekly survival was 0.989 ? 0.007 ( ?SE). Survival rates of banded and radio-marked individuals were not different (alpha hat [S_radioed, ~ S_banded]=log [S hat _radioed/ S hat _banded]=0.0239 ? 0.0435). Fidelity rates (weekly probability of remaining in a stratum) did not differ between geographic strata (psi hat=0.911 ? 0.020; alpha hat [psi11, psi22]=0.0161 ? 0.047), and recapture rates ( = 0.097 ? 0.016) banded and radio-marked individuals were not different (alpha hat [p_radioed, p_banded]=0.145 ? 0.655). Combining these data types in a common model resulted in more precise estimates of movement and recapture rates than separate estimation, but ability to detect stratum or mark-specific differences in parameters was week. We conducted simulation trials to investigate the effects of varying study designs on parameter accuracy and statistical power to detect important differences. Parameter accuracy was high (relative bias [RBIAS] <2 %) and confidence interval coverage close to nominal, except for survival estimates of banded birds for the 'off study area' stratum, which were negatively biased (RBIAS -7 to -15%) when sample sizes were small (5-10 banded or radioed animals 'released' per time interval). To provide adequate data for useful inference from this model, study designs should seek a minimum of 25 animals of each marking type observed (marked or observed via telemetry) in each time period and geographic stratum.
Modelling heterogeneity variances in multiple treatment comparison meta-analysis--are informative priors the better solution?

PubMed

Thorlund, Kristian; Thabane, Lehana; Mills, Edward J

2013-01-11

Multiple treatment comparison (MTC) meta-analyses are commonly modeled in a Bayesian framework, and weakly informative priors are typically preferred to mirror familiar data driven frequentist approaches. Random-effects MTCs have commonly modeled heterogeneity under the assumption that the between-trial variance for all involved treatment comparisons are equal (i.e., the 'common variance' assumption). This approach 'borrows strength' for heterogeneity estimation across treatment comparisons, and thus, ads valuable precision when data is sparse. The homogeneous variance assumption, however, is unrealistic and can severely bias variance estimates. Consequently 95% credible intervals may not retain nominal coverage, and treatment rank probabilities may become distorted. Relaxing the homogeneous variance assumption may be equally problematic due to reduced precision. To regain good precision, moderately informative variance priors or additional mathematical assumptions may be necessary. In this paper we describe four novel approaches to modeling heterogeneity variance - two novel model structures, and two approaches for use of moderately informative variance priors. We examine the relative performance of all approaches in two illustrative MTC data sets. We particularly compare between-study heterogeneity estimates and model fits, treatment effect estimates and 95% credible intervals, and treatment rank probabilities. In both data sets, use of moderately informative variance priors constructed from the pair wise meta-analysis data yielded the best model fit and narrower credible intervals. Imposing consistency equations on variance estimates, assuming variances to be exchangeable, or using empirically informed variance priors also yielded good model fits and narrow credible intervals. The homogeneous variance model yielded high precision at all times, but overall inadequate estimates of between-trial variances. Lastly, treatment rankings were similar among the novel approaches, but considerably different when compared with the homogenous variance approach. MTC models using a homogenous variance structure appear to perform sub-optimally when between-trial variances vary between comparisons. Using informative variance priors, assuming exchangeability or imposing consistency between heterogeneity variances can all ensure sufficiently reliable and realistic heterogeneity estimation, and thus more reliable MTC inferences. All four approaches should be viable candidates for replacing or supplementing the conventional homogeneous variance MTC model, which is currently the most widely used in practice.
Efficient estimation of abundance for patchily distributed populations via two-phase, adaptive sampling.

USGS Publications Warehouse

Conroy, M.J.; Runge, J.P.; Barker, R.J.; Schofield, M.R.; Fonnesbeck, C.J.

2008-01-01

Many organisms are patchily distributed, with some patches occupied at high density, others at lower densities, and others not occupied. Estimation of overall abundance can be difficult and is inefficient via intensive approaches such as capture-mark-recapture (CMR) or distance sampling. We propose a two-phase sampling scheme and model in a Bayesian framework to estimate abundance for patchily distributed populations. In the first phase, occupancy is estimated by binomial detection samples taken on all selected sites, where selection may be of all sites available, or a random sample of sites. Detection can be by visual surveys, detection of sign, physical captures, or other approach. At the second phase, if a detection threshold is achieved, CMR or other intensive sampling is conducted via standard procedures (grids or webs) to estimate abundance. Detection and CMR data are then used in a joint likelihood to model probability of detection in the occupancy sample via an abundance-detection model. CMR modeling is used to estimate abundance for the abundance-detection relationship, which in turn is used to predict abundance at the remaining sites, where only detection data are collected. We present a full Bayesian modeling treatment of this problem, in which posterior inference on abundance and other parameters (detection, capture probability) is obtained under a variety of assumptions about spatial and individual sources of heterogeneity. We apply the approach to abundance estimation for two species of voles (Microtus spp.) in Montana, USA. We also use a simulation study to evaluate the frequentist properties of our procedure given known patterns in abundance and detection among sites as well as design criteria. For most population characteristics and designs considered, bias and mean-square error (MSE) were low, and coverage of true parameter values by Bayesian credibility intervals was near nominal. Our two-phase, adaptive approach allows efficient estimation of abundance of rare and patchily distributed species and is particularly appropriate when sampling in all patches is impossible, but a global estimate of abundance is required.
Multiple imputation methods for bivariate outcomes in cluster randomised trials.

PubMed

DiazOrdaz, K; Kenward, M G; Gomes, M; Grieve, R

2016-09-10

Missing observations are common in cluster randomised trials. The problem is exacerbated when modelling bivariate outcomes jointly, as the proportion of complete cases is often considerably smaller than the proportion having either of the outcomes fully observed. Approaches taken to handling such missing data include the following: complete case analysis, single-level multiple imputation that ignores the clustering, multiple imputation with a fixed effect for each cluster and multilevel multiple imputation. We contrasted the alternative approaches to handling missing data in a cost-effectiveness analysis that uses data from a cluster randomised trial to evaluate an exercise intervention for care home residents. We then conducted a simulation study to assess the performance of these approaches on bivariate continuous outcomes, in terms of confidence interval coverage and empirical bias in the estimated treatment effects. Missing-at-random clustered data scenarios were simulated following a full-factorial design. Across all the missing data mechanisms considered, the multiple imputation methods provided estimators with negligible bias, while complete case analysis resulted in biased treatment effect estimates in scenarios where the randomised treatment arm was associated with missingness. Confidence interval coverage was generally in excess of nominal levels (up to 99.8%) following fixed-effects multiple imputation and too low following single-level multiple imputation. Multilevel multiple imputation led to coverage levels of approximately 95% throughout. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.
A simulation evaluation of the engine monitoring and control system display

NASA Technical Reports Server (NTRS)

Abbott, Terence S.

1990-01-01

The Engine Monitoring and Control System (E-MACS) display is a new concept for an engine instrument display, the purpose of which is to provide an enhanced means for a pilot to control and monitor aircraft engine performance. It provides graphically-presented information about performance capabilities, current performance, and engine component or subsystem operational conditions relative to nominal conditions. The concept was evaluated by sixteen pilot-subjects against a traditional, state-of-the-art electronic engine display format. The results of this evaluation showed a substantial pilot preference for the E-MACS display relative to the traditional display. The results of the failure detection portion of the evaluation showed a 100 percent detection rate for the E-MACS display relative to a 57 percent rate for the traditional display. From these results, it is concluded that by providing this type of information in the cockpit, a reduction in pilot workload and an enhanced ability for detecting degraded or off-nominal conditions is probable, thus leading to an increase in operational safety.
Characterization of nonGaussian atmospheric turbulence for prediction of aircraft response statistics

NASA Technical Reports Server (NTRS)

Mark, W. D.

1977-01-01

Mathematical expressions were derived for the exceedance rates and probability density functions of aircraft response variables using a turbulence model that consists of a low frequency component plus a variance modulated Gaussian turbulence component. The functional form of experimentally observed concave exceedance curves was predicted theoretically, the strength of the concave contribution being governed by the coefficient of variation of the time fluctuating variance of the turbulence. Differences in the functional forms of response exceedance curves and probability densities also were shown to depend primarily on this same coefficient of variation. Criteria were established for the validity of the local stationary assumption that is required in the derivations of the exceedance curves and probability density functions. These criteria are shown to depend on the relative time scale of the fluctuations in the variance, the fluctuations in the turbulence itself, and on the nominal duration of the relevant aircraft impulse response function. Metrics that can be generated from turbulence recordings for testing the validity of the local stationary assumption were developed.
Effects of sampling conditions on DNA-based estimates of American black bear abundance

USGS Publications Warehouse

Laufenberg, Jared S.; Van Manen, Frank T.; Clark, Joseph D.

2013-01-01

DNA-based capture-mark-recapture techniques are commonly used to estimate American black bear (Ursus americanus) population abundance (N). Although the technique is well established, many questions remain regarding study design. In particular, relationships among N, capture probability of heterogeneity mixtures A and B (pA and pB, respectively, or p, collectively), the proportion of each mixture (π), number of capture occasions (k), and probability of obtaining reliable estimates of N are not fully understood. We investigated these relationships using 1) an empirical dataset of DNA samples for which true N was unknown and 2) simulated datasets with known properties that represented a broader array of sampling conditions. For the empirical data analysis, we used the full closed population with heterogeneity data type in Program MARK to estimate N for a black bear population in Great Smoky Mountains National Park, Tennessee. We systematically reduced the number of those samples used in the analysis to evaluate the effect that changes in capture probabilities may have on parameter estimates. Model-averaged N for females and males were 161 (95% CI = 114–272) and 100 (95% CI = 74–167), respectively (pooled N = 261, 95% CI = 192–419), and the average weekly p was 0.09 for females and 0.12 for males. When we reduced the number of samples of the empirical data, support for heterogeneity models decreased. For the simulation analysis, we generated capture data with individual heterogeneity covering a range of sampling conditions commonly encountered in DNA-based capture-mark-recapture studies and examined the relationships between those conditions and accuracy (i.e., probability of obtaining an estimated N that is within 20% of true N), coverage (i.e., probability that 95% confidence interval includes true N), and precision (i.e., probability of obtaining a coefficient of variation ≤20%) of estimates using logistic regression. The capture probability for the larger of 2 mixture proportions of the population (i.e., pA or pB, depending on the value of π) was most important for predicting accuracy and precision, whereas capture probabilities of both mixture proportions (pA and pB) were important to explain variation in coverage. Based on sampling conditions similar to parameter estimates from the empirical dataset (pA = 0.30, pB = 0.05, N = 250, π = 0.15, and k = 10), predicted accuracy and precision were low (60% and 53%, respectively), whereas coverage was high (94%). Increasing pB, the capture probability for the predominate but most difficult to capture proportion of the population, was most effective to improve accuracy under those conditions. However, manipulation of other parameters may be more effective under different conditions. In general, the probabilities of obtaining accurate and precise estimates were best when p≥ 0.2. Our regression models can be used by managers to evaluate specific sampling scenarios and guide development of sampling frameworks or to assess reliability of DNA-based capture-mark-recapture studies.
Care 3 phase 2 report, maintenance manual

NASA Technical Reports Server (NTRS)

Bryant, L. A.; Stiffler, J. J.

1982-01-01

CARE 3 (Computer-Aided Reliability Estimation, version three) is a computer program designed to help estimate the reliability of complex, redundant systems. Although the program can model a wide variety of redundant structures, it was developed specifically for fault-tolerant avionics systems--systems distinguished by the need for extremely reliable performance since a system failure could well result in the loss of human life. It substantially generalizes the class of redundant configurations that could be accommodated, and includes a coverage model to determine the various coverage probabilities as a function of the applicable fault recovery mechanisms (detection delay, diagnostic scheduling interval, isolation and recovery delay, etc.). CARE 3 further generalizes the class of system structures that can be modeled and greatly expands the coverage model to take into account such effects as intermittent and transient faults, latent faults, error propagation, etc.
Uncritical and unbalanced coverage of synthetic biology in the Nordic press.

PubMed

Ancillotti, Mirko; Holmberg, Niklas; Lindfelt, Mikael; Eriksson, Stefan

2017-02-01

Synthetic biology will probably have a high impact on a variety of fields, such as healthcare, environment, biofuels, agriculture, and so on. A driving theme in European research policy is the importance of maintaining public legitimacy and support. Media can influence public attitudes and are therefore an important object of study. Through qualitative content analysis, this study investigates the press coverage of synthetic biology in the major Nordic countries between 2009 and 2014. The press coverage was found to be event-driven and there were striking similarities between countries when it comes to framing, language use, and treated themes. Reporters showed a marked dependence on their sources, mainly scientists and stakeholders, who thus drives the media agenda. The media portrayal was very positive, with an optimistic look at future benefits and very little discussion of possible risks.
Which are the greatest recent discoveries and the greatest future challenges in nutrition?

PubMed

Katan, M B; Boekschoten, M V; Connor, W E; Mensink, R P; Seidell, J; Vessby, B; Willett, W

2009-01-01

Nutrition science aims to create new knowledge, but scientists rarely sit back to reflect on what nutrition research has achieved in recent decades. We report the outcome of a 1-day symposium at which the audience was asked to vote on the greatest discoveries in nutrition since 1976 and on the greatest challenges for the coming 30 years. Most of the 128 participants were Dutch scientists working in nutrition or related biomedical and public health fields. Candidate discoveries and challenges were nominated by five invited speakers and by members of the audience. Ballot forms were then prepared on which participants selected one discovery and one challenge. A total of 15 discoveries and 14 challenges were nominated. The audience elected Folic acid prevents birth defects as the greatest discovery in nutrition science since 1976. Controlling obesity and insulin resistance through activity and diet was elected as the greatest challenge for the coming 30 years. This selection was probably biased by the interests and knowledge of the speakers and the audience. For the present review, we therefore added 12 discoveries from the period 1976 to 2006 that we judged worthy of consideration, but that had not been nominated at the meeting. The meeting did not represent an objective selection process, but it did demonstrate that the past 30 years have yielded major new discoveries in nutrition and health.
Associations between friends' disordered eating and muscle-enhancing behaviors

PubMed Central

Eisenberg, Marla E.; Wall, Melanie; Shim, Jin Joo; Bruening, Meg; Loth, Katie; Neumark-Sztainer, Dianne

2012-01-01

Dieting, unhealthy weight control and muscle-enhancing behaviors are common among adolescents: friends are a probable source of influence on these behaviors. The present study uses data provided by nominated friends to examine associations between friends' disordered eating and muscle-enhancing behaviors and participants' own behaviors in a diverse sample of American youth. Male and female adolescents (mean age = 14.4) completed surveys and identified their friends from a class roster; friends' survey data were then linked to each participant. Participants (N = 2126) who had at least one nominated friend were included in the analytic sample. Independent variables were created using the same weight control and muscle-enhancing behaviors reported by nominated friends, and were used in logistic regression models to test associations between participants' and their friends' behaviors, stratified by gender. Results indicated that dieting, disordered eating and muscle-enhancing behaviors were common in this sample, and selected friends' behaviors were associated with the same behaviors in participants. For example, girls whose friends reported extreme weight control behaviors had significantly greater odds of using these behaviors than girls whose friends did not report these same behaviors (OR = 2.39). This research suggests that friends' weight- and shape-related behaviors are a feature of social relationships, and is the first report demonstrating these associations for muscle-enhancing behaviors. Capitalizing on the social element may be important to the development of increasingly effective intervention and prevention programs. PMID:23010337
Effect of Medicaid Expansions on Health Insurance Coverage and Access to Care among Low-Income Adults with Behavioral Health Conditions.

PubMed

Wen, Hefei; Druss, Benjamin G; Cummings, Janet R

2015-12-01

To examine the effect of Medicaid expansions on health insurance coverage and access to care among low-income adults with behavioral health conditions. Nine years (2004-2012) of individual-level cross-sectional data from a restricted-access version of National Survey on Drug Use and Health. A quasi-experimental difference-in-differences design comparing outcomes among residents in 14 states that implemented Medicaid expansions for low-income adults under the Section §1115 waiver with those residing in the rest of the country. The analytic sample includes low-income adult respondents with household incomes below 200 percent of the federal poverty level who have a behavioral health condition: approximately 28,400 low-income adults have past-year serious psychological distress and 24,900 low-income adults have a past-year substance use disorder (SUD). Among low-income adults with behavioral health conditions, Medicaid expansions were associated with a reduction in the rate of uninsurance (p < .05), a reduction in the probability of perceiving an unmet need for mental health (MH) treatment (p < .05) and for SUD treatment (p < .05), as well as an increase in the probability of receiving MH treatment (p < .01). The ongoing implementation of Medicaid expansions has the potential to improve health insurance coverage and access to care for low-income adults with behavioral health conditions. © Health Research and Educational Trust.
[Health insurance for infants and infant vaccination related to forced-displacement in Colombia].

PubMed

Ruiz-Rodríguez, Myriam; Vera-Cala, Lina M; López-Barbosa, Nahyr

2008-01-01

Determining vaccination coverage amongst children (<5 years old) having multiple socio-economic risk factors and their relationship to insurance status. This was a cross-sectional study of 514 families from urban settlements receiving people displaced by the armed conflict in 4 municipalities in the Santander department ( Colombia ). The households were selected by probabilistic sampling, using proportional modelling by municipality. Immunisation data was collected from vaccination cards; interviews provided socio-demographic data. The dependent variable consisted of having the complete vaccination scheme by age according to the official Ministry of Social Protection's programme. The probability of being vaccinated was modelled by a logistical regression, adjusted for sociodemographic variables. 369 children were studied, of whom 48,8 % belonged to families displaced by the armed conflict. 46,1 % of the people being interviewed presented their vaccination cards. Contrary to what had been expected, only 21,2 % of those having a vaccination card were insured and 22,9 % of them had a complete vaccination scheme for their age. The probability of having a complete vaccination scheme for those individuals who were covered by the subsidised health system was 2,4 times higher when compared to those who were not insured (p=0.042). Low vaccination coverage indicated barriers for people living in conditions of poverty and displacement obtaining health services and low insurance coverage suggested faults in health insurance policies addressing similar populations.
Medicaid Coverage Expansions and Cigarette Smoking Cessation Among Low-income Adults.

PubMed

Koma, Jonathan W; Donohue, Julie M; Barry, Colleen L; Huskamp, Haiden A; Jarlenski, Marian

2017-12-01

Expanding Medicaid coverage to low-income adults may have increased smoking cessation through improved access to evidence-based treatments. Our study sought to determine if states' decisions to expand Medicaid increased recent smoking cessation. Using pooled cross-sectional data from the Behavioral Risk Factor Surveillance Survey for the years 2011-2015, we examined the association between state Medicaid coverage and the probability of recent smoking cessation among low-income adults without dependent children who were current or former smokers (n=36,083). We used difference-in-differences estimation to examine the effects of Medicaid coverage on smoking cessation, comparing low-income adult smokers in states with Medicaid coverage to comparable adults in states without Medicaid coverage, with ages 18-64 years to those ages 65 years and above. Analyses were conducted for the full sample and stratified by sex. Residence in a state with Medicaid coverage among low-income adult smokers ages 18-64 years was associated with an increase in recent smoking cessation of 2.1 percentage points (95% confidence interval, 0.25-3.9). In the comparison group of individuals ages 65 years and above, residence in a state with Medicaid coverage expansion was not associated with a change in recent smoking cessation (-0.1 percentage point, 95% confidence interval, -2.1 to 1.8). Similar increases in smoking cessation among those ages 18-64 years were estimated for females and males (1.9 and 2.2 percentage point, respectively). Findings are consistent with the hypothesis that Medicaid coverage expansions may have increased smoking cessation among low-income adults without dependent children via greater access to preventive health care services, including evidence-based smoking cessation services.
Severity of pain is associated with insufficient energy coverage in hospitalised patients: A cross-sectional study.

PubMed

Makhlouf, Anne-Marie; Kossovsky, Michel P; Gurba, France; Pautex, Sophie; Chikhi, Marinette; Pichard, Claude; Genton, Laurence

2018-03-17

The severity of pain is routinely assessed in hospitalised patients but the impact of pain and pain control on energy coverage has been poorly studied. This One-day cross-sectional observational study assessed the association between severity of pain and coverage of energy needs in hospitalised patients. Foods provided and consumed were assessed on one day by dedicated dieticians for unselected hospitalised patients receiving three meals per day. Severity of pain was evaluated by a visual analogue scale at the mealtimes, averaged over the study day, and categorized as no pain, slight, moderate or severe pain. The coverage of energy needs was expressed in percentage of predicted needs. Among the 755 included patients, 63% reported having pain. Severe pain was associated with a lower energy coverage than no pain (p = 0.001) or slight pain (p = 0.001). Insufficient energy coverage, defined as ≤70% of predicted needs, occurred in 13% of the patients. In univariate logistic regressions, predictors of insufficient energy coverage were severe pain as compared to no pain (OR 2.38; 95% CI 1.21, 4.64) and treatment with opioid drugs as compared to no pain killer (OR 1.73; 95% CI 1.07, 2.79). When including sex, age, body mass index, treatment with analgesics and severity of pain in a multivariate logistic regression, severe pain more than doubled the risk of insufficient energy coverage (OR 2.32; CI 1.15, 4.66). Patients experiencing severe pain have a high risk of insufficient energy coverage. Optimal pain control is probably critical to prevent underfeeding in the hospital. Identifier no NCT02463565 on www.ClinicalTrials.gov. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
Sensitivity of postplanning target and OAR coverage estimates to dosimetric margin distribution sampling parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu Huijun; Gordon, J. James; Siebers, Jeffrey V.

2011-02-15

Purpose: A dosimetric margin (DM) is the margin in a specified direction between a structure and a specified isodose surface, corresponding to a prescription or tolerance dose. The dosimetric margin distribution (DMD) is the distribution of DMs over all directions. Given a geometric uncertainty model, representing inter- or intrafraction setup uncertainties or internal organ motion, the DMD can be used to calculate coverage Q, which is the probability that a realized target or organ-at-risk (OAR) dose metric D{sub v} exceeds the corresponding prescription or tolerance dose. Postplanning coverage evaluation quantifies the percentage of uncertainties for which target and OAR structuresmore » meet their intended dose constraints. The goal of the present work is to evaluate coverage probabilities for 28 prostate treatment plans to determine DMD sampling parameters that ensure adequate accuracy for postplanning coverage estimates. Methods: Normally distributed interfraction setup uncertainties were applied to 28 plans for localized prostate cancer, with prescribed dose of 79.2 Gy and 10 mm clinical target volume to planning target volume (CTV-to-PTV) margins. Using angular or isotropic sampling techniques, dosimetric margins were determined for the CTV, bladder and rectum, assuming shift invariance of the dose distribution. For angular sampling, DMDs were sampled at fixed angular intervals {omega} (e.g., {omega}=1 deg., 2 deg., 5 deg., 10 deg., 20 deg.). Isotropic samples were uniformly distributed on the unit sphere resulting in variable angular increments, but were calculated for the same number of sampling directions as angular DMDs, and accordingly characterized by the effective angular increment {omega}{sub eff}. In each direction, the DM was calculated by moving the structure in radial steps of size {delta}(=0.1,0.2,0.5,1 mm) until the specified isodose was crossed. Coverage estimation accuracy {Delta}Q was quantified as a function of the sampling parameters {omega} or {omega}{sub eff} and {delta}. Results: The accuracy of coverage estimates depends on angular and radial DMD sampling parameters {omega} or {omega}{sub eff} and {delta}, as well as the employed sampling technique. Target |{Delta}Q|<1% and OAR |{Delta}Q|<3% can be achieved with sampling parameters {omega} or {omega}{sub eff}=20 deg., {delta}=1 mm. Better accuracy (target |{Delta}Q|<0.5% and OAR |{Delta}Q|<{approx}1%) can be achieved with {omega} or {omega}{sub eff}=10 deg., {delta}=0.5 mm. As the number of sampling points decreases, the isotropic sampling method maintains better accuracy than fixed angular sampling. Conclusions: Coverage estimates for post-planning evaluation are essential since coverage values of targets and OARs often differ from the values implied by the static margin-based plans. Finer sampling of the DMD enables more accurate assessment of the effect of geometric uncertainties on coverage estimates prior to treatment. DMD sampling with {omega} or {omega}{sub eff}=10 deg. and {delta}=0.5 mm should be adequate for planning purposes.« less
Sensitivity of postplanning target and OAR coverage estimates to dosimetric margin distribution sampling parameters.

PubMed

Xu, Huijun; Gordon, J James; Siebers, Jeffrey V

2011-02-01

A dosimetric margin (DM) is the margin in a specified direction between a structure and a specified isodose surface, corresponding to a prescription or tolerance dose. The dosimetric margin distribution (DMD) is the distribution of DMs over all directions. Given a geometric uncertainty model, representing inter- or intrafraction setup uncertainties or internal organ motion, the DMD can be used to calculate coverage Q, which is the probability that a realized target or organ-at-risk (OAR) dose metric D, exceeds the corresponding prescription or tolerance dose. Postplanning coverage evaluation quantifies the percentage of uncertainties for which target and OAR structures meet their intended dose constraints. The goal of the present work is to evaluate coverage probabilities for 28 prostate treatment plans to determine DMD sampling parameters that ensure adequate accuracy for postplanning coverage estimates. Normally distributed interfraction setup uncertainties were applied to 28 plans for localized prostate cancer, with prescribed dose of 79.2 Gy and 10 mm clinical target volume to planning target volume (CTV-to-PTV) margins. Using angular or isotropic sampling techniques, dosimetric margins were determined for the CTV, bladder and rectum, assuming shift invariance of the dose distribution. For angular sampling, DMDs were sampled at fixed angular intervals w (e.g., w = 1 degree, 2 degrees, 5 degrees, 10 degrees, 20 degrees). Isotropic samples were uniformly distributed on the unit sphere resulting in variable angular increments, but were calculated for the same number of sampling directions as angular DMDs, and accordingly characterized by the effective angular increment omega eff. In each direction, the DM was calculated by moving the structure in radial steps of size delta (=0.1, 0.2, 0.5, 1 mm) until the specified isodose was crossed. Coverage estimation accuracy deltaQ was quantified as a function of the sampling parameters omega or omega eff and delta. The accuracy of coverage estimates depends on angular and radial DMD sampling parameters omega or omega eff and delta, as well as the employed sampling technique. Target deltaQ/ < l% and OAR /deltaQ/ < 3% can be achieved with sampling parameters omega or omega eef = 20 degrees, delta =1 mm. Better accuracy (target /deltaQ < 0.5% and OAR /deltaQ < approximately 1%) can be achieved with omega or omega eff = 10 degrees, delta = 0.5 mm. As the number of sampling points decreases, the isotropic sampling method maintains better accuracy than fixed angular sampling. Coverage estimates for post-planning evaluation are essential since coverage values of targets and OARs often differ from the values implied by the static margin-based plans. Finer sampling of the DMD enables more accurate assessment of the effect of geometric uncertainties on coverage estimates prior to treatment. DMD sampling with omega or omega eff = 10 degrees and delta = 0.5 mm should be adequate for planning purposes.
WE-AB-209-08: Novel Beam-Specific Adaptive Margins for Reducing Organ-At-Risk Doses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsang, H; Kamerling, CP; Ziegenhein, P

2016-06-15

Purpose: Current practice of using 3D margins in radiotherapy with high-energy photon beams provides larger-than-required target coverage. According to the photon depth-dose curve, target displacements in beam direction result in minute changes in dose delivered. We exploit this behavior by generating margins on a per-beam basis which simultaneously account for the relative distance of the target and adjacent organs-at-risk (OARs). Methods: For each beam, we consider only geometrical uncertainties of the target location perpendicular to beam direction. By weighting voxels based on its proximity to an OAR, we generate adaptive margins that yield similar overall target coverage probability and reducedmore » OAR dose-burden, at the expense of increased target volume. Three IMRT plans, using 3D margins and 2D per-beam margins with and without adaptation, were generated for five prostate patients with a prescription dose Dpres of 78Gy in 2Gy fractions using identical optimisation constraints. Systematic uncertainties of 1.1, 1.1, 1.5mm in the LR, SI, and AP directions, respectively, and 0.9, 1.1, 1.0mm for the random uncertainties, were assumed. A verification tool was employed to simulate the effects of systematic and random errors using a population size of 50,000. The fraction of the population that satisfies or violates a given DVH constraint was used for comparison. Results: We observe similar target coverage across all plans, with at least 97.5% of the population meeting the D98%>95%Dpres constraint. When looking at the probability of the population receiving D5<70Gy for the rectum, we observed median absolute increases of 23.61% (range, 2.15%–27.85%) and 6.97% (range, 0.65%–17.76%) using per-beam margins with and without adaptation, respectively, relative to using 3D margins. Conclusion: We observed sufficient and similar target coverage using per-beam margins. By adapting each per-beam margin away from an OAR, we can further reduce OAR dose without significantly lowering target coverage probability by irradiating more less-important tissues. This work is supported by Cancer Research UK under Programme C33589/A19908. Research at ICR is also supported by Cancer Research UK under Programme C33589/A19727 and NHS funding to the NIHR Biomedical Research Centre at RMH and ICR.« less

Improving default risk prediction using Bayesian model uncertainty techniques.

PubMed

Kazemi, Reza; Mosleh, Ali

2012-11-01

Credit risk is the potential exposure of a creditor to an obligor's failure or refusal to repay the debt in principal or interest. The potential of exposure is measured in terms of probability of default. Many models have been developed to estimate credit risk, with rating agencies dating back to the 19th century. They provide their assessment of probability of default and transition probabilities of various firms in their annual reports. Regulatory capital requirements for credit risk outlined by the Basel Committee on Banking Supervision have made it essential for banks and financial institutions to develop sophisticated models in an attempt to measure credit risk with higher accuracy. The Bayesian framework proposed in this article uses the techniques developed in physical sciences and engineering for dealing with model uncertainty and expert accuracy to obtain improved estimates of credit risk and associated uncertainties. The approach uses estimates from one or more rating agencies and incorporates their historical accuracy (past performance data) in estimating future default risk and transition probabilities. Several examples demonstrate that the proposed methodology can assess default probability with accuracy exceeding the estimations of all the individual models. Moreover, the methodology accounts for potentially significant departures from "nominal predictions" due to "upsetting events" such as the 2008 global banking crisis. © 2012 Society for Risk Analysis.
Digital, Satellite-Based Aeronautical Communication

NASA Technical Reports Server (NTRS)

Davarian, F.

1989-01-01

Satellite system relays communication between aircraft and stations on ground. System offers better coverage with direct communication between air and ground, costs less and makes possible new communication services. Carries both voice and data. Because many data exchanged between aircraft and ground contain safety-related information, probability of bit errors essential.
Assessment and Verification of SLS Block 1-B Exploration Upper Stage State and Stage Disposal Performance

NASA Technical Reports Server (NTRS)

Patrick, Sean; Oliver, Emerson

2018-01-01

One of the SLS Navigation System's key performance requirements is a constraint on the payload system's delta-v allocation to correct for insertion errors due to vehicle state uncertainty at payload separation. The SLS navigation team has developed a Delta-Delta-V analysis approach to assess the effect on trajectory correction maneuver (TCM) design needed to correct for navigation errors. This approach differs from traditional covariance analysis based methods and makes no assumptions with regard to the propagation of the state dynamics. This allows for consideration of non-linearity in the propagation of state uncertainties. The Delta-Delta-V analysis approach re-optimizes perturbed SLS mission trajectories by varying key mission states in accordance with an assumed state error. The state error is developed from detailed vehicle 6-DOF Monte Carlo analysis or generated using covariance analysis. These perturbed trajectories are compared to a nominal trajectory to determine necessary TCM design. To implement this analysis approach, a tool set was developed which combines the functionality of a 3-DOF trajectory optimization tool, Copernicus, and a detailed 6-DOF vehicle simulation tool, Marshall Aerospace Vehicle Representation in C (MAVERIC). In addition to delta-v allocation constraints on SLS navigation performance, SLS mission requirement dictate successful upper stage disposal. Due to engine and propellant constraints, the SLS Exploration Upper Stage (EUS) must dispose into heliocentric space by means of a lunar fly-by maneuver. As with payload delta-v allocation, upper stage disposal maneuvers must place the EUS on a trajectory that maximizes the probability of achieving a heliocentric orbit post Lunar fly-by considering all sources of vehicle state uncertainty prior to the maneuver. To ensure disposal, the SLS navigation team has developed an analysis approach to derive optimal disposal guidance targets. This approach maximizes the state error covariance prior to the maneuver to develop and re-optimize a nominal disposal maneuver (DM) target that, if achieved, would maximize the potential for successful upper stage disposal. For EUS disposal analysis, a set of two tools was developed. The first considers only the nominal pre-disposal maneuver state, vehicle constraints, and an a priori estimate of the state error covariance. In the analysis, the optimal nominal disposal target is determined. This is performed by re-formulating the trajectory optimization to consider constraints on the eigenvectors of the error ellipse applied to the nominal trajectory. A bisection search methodology is implemented in the tool to refine these dispersions resulting in the maximum dispersion feasible for successful disposal via lunar fly-by. Success is defined based on the probability that the vehicle will not impact the lunar surface and will achieve a characteristic energy (C3) relative to the Earth such that it is no longer in the Earth-Moon system. The second tool propagates post-disposal maneuver states to determine the success of disposal for provided trajectory achieved states. This is performed using the optimized nominal target within the 6-DOF vehicle simulation. This paper will discuss the application of the Delta-Delta-V analysis approach for performance evaluation as well as trajectory re-optimization so as to demonstrate the system's capability in meeting performance constraints. Additionally, further discussion of the implementation of assessing disposal analysis will be provided.
Applications of asymptotic confidence intervals with continuity corrections for asymmetric comparisons in noninferiority trials.

PubMed

Soulakova, Julia N; Bright, Brianna C

2013-01-01

A large-sample problem of illustrating noninferiority of an experimental treatment over a referent treatment for binary outcomes is considered. The methods of illustrating noninferiority involve constructing the lower two-sided confidence bound for the difference between binomial proportions corresponding to the experimental and referent treatments and comparing it with the negative value of the noninferiority margin. The three considered methods, Anbar, Falk-Koch, and Reduced Falk-Koch, handle the comparison in an asymmetric way, that is, only the referent proportion out of the two, experimental and referent, is directly involved in the expression for the variance of the difference between two sample proportions. Five continuity corrections (including zero) are considered with respect to each approach. The key properties of the corresponding methods are evaluated via simulations. First, the uncorrected two-sided confidence intervals can, potentially, have smaller coverage probability than the nominal level even for moderately large sample sizes, for example, 150 per group. Next, the 15 testing methods are discussed in terms of their Type I error rate and power. In the settings with a relatively small referent proportion (about 0.4 or smaller), the Anbar approach with Yates' continuity correction is recommended for balanced designs and the Falk-Koch method with Yates' correction is recommended for unbalanced designs. For relatively moderate (about 0.6) and large (about 0.8 or greater) referent proportion, the uncorrected Reduced Falk-Koch method is recommended, although in this case, all methods tend to be over-conservative. These results are expected to be used in the design stage of a noninferiority study when asymmetric comparisons are envisioned. Copyright © 2013 John Wiley & Sons, Ltd.
Statistical inference on censored data for targeted clinical trials under enrichment design.

PubMed

Chen, Chen-Fang; Lin, Jr-Rung; Liu, Jen-Pei

2013-01-01

For the traditional clinical trials, inclusion and exclusion criteria are usually based on some clinical endpoints; the genetic or genomic variability of the trial participants are not totally utilized in the criteria. After completion of the human genome project, the disease targets at the molecular level can be identified and can be utilized for the treatment of diseases. However, the accuracy of diagnostic devices for identification of such molecular targets is usually not perfect. Some of the patients enrolled in targeted clinical trials with a positive result for the molecular target might not have the specific molecular targets. As a result, the treatment effect may be underestimated in the patient population truly with the molecular target. To resolve this issue, under the exponential distribution, we develop inferential procedures for the treatment effects of the targeted drug based on the censored endpoints in the patients truly with the molecular targets. Under an enrichment design, we propose using the expectation-maximization algorithm in conjunction with the bootstrap technique to incorporate the inaccuracy of the diagnostic device for detection of the molecular targets on the inference of the treatment effects. A simulation study was conducted to empirically investigate the performance of the proposed methods. Simulation results demonstrate that under the exponential distribution, the proposed estimator is nearly unbiased with adequate precision, and the confidence interval can provide adequate coverage probability. In addition, the proposed testing procedure can adequately control the size with sufficient power. On the other hand, when the proportional hazard assumption is violated, additional simulation studies show that the type I error rate is not controlled at the nominal level and is an increasing function of the positive predictive value. A numerical example illustrates the proposed procedures. Copyright © 2013 John Wiley & Sons, Ltd.
Men who work at age 70 or older.

PubMed

Ozawa, Martha N; Lum, Terry Y

2005-01-01

The federal policy on older workers has shifted from the encouragement of early withdrawal from the labor force to the encouragement of continuous participation in the labor force. In this light, it is instructive to investigate the backgrounds of elderly people who work at age 70 or older. This article presents the findings of a study, using data from the 1993 Asset and Health Dynamics of the Oldest Old Study, that investigated the effects of health, economic conditions (net worth, employer-provided pensions, and supplemental medical insurance coverage), education, and spouse's work status on the probability of working among men aged 70 or older. The study addressed the probability of working, the probability of working fulltime and of working part-time, and the probability of being self-employed and of being employed by others. Implications for policy are discussed.
CORNAS: coverage-dependent RNA-Seq analysis of gene expression data without biological replicates.

PubMed

Low, Joel Z B; Khang, Tsung Fei; Tammi, Martti T

2017-12-28

In current statistical methods for calling differentially expressed genes in RNA-Seq experiments, the assumption is that an adjusted observed gene count represents an unknown true gene count. This adjustment usually consists of a normalization step to account for heterogeneous sample library sizes, and then the resulting normalized gene counts are used as input for parametric or non-parametric differential gene expression tests. A distribution of true gene counts, each with a different probability, can result in the same observed gene count. Importantly, sequencing coverage information is currently not explicitly incorporated into any of the statistical models used for RNA-Seq analysis. We developed a fast Bayesian method which uses the sequencing coverage information determined from the concentration of an RNA sample to estimate the posterior distribution of a true gene count. Our method has better or comparable performance compared to NOISeq and GFOLD, according to the results from simulations and experiments with real unreplicated data. We incorporated a previously unused sequencing coverage parameter into a procedure for differential gene expression analysis with RNA-Seq data. Our results suggest that our method can be used to overcome analytical bottlenecks in experiments with limited number of replicates and low sequencing coverage. The method is implemented in CORNAS (Coverage-dependent RNA-Seq), and is available at https://github.com/joel-lzb/CORNAS .
Stability of children's insurance coverage and implications for access to care: evidence from the Survey of Income and Program Participation.

PubMed

Buchmueller, Thomas; Orzol, Sean M; Shore-Sheppard, Lara

2014-06-01

Even as the number of children with health insurance has increased, coverage transitions--movement into and out of coverage and between public and private insurance--have become more common. Using data from 1996 to 2005, we examine whether insurance instability has implications for access to primary care. Because unobserved factors related to parental behavior and child health may affect both the stability of coverage and utilization, we estimate the relationship between insurance and the probability that a child has at least one physician visit per year using a model that includes child fixed effects to account for unobserved heterogeneity. Although we find that unobserved heterogeneity is an important factor influencing cross-sectional correlations, conditioning on child fixed effects we find a statistically and economically significant relationship between insurance coverage stability and access to care. Children who have part-year public or private insurance are more likely to have at least one doctor's visit than children who are uninsured for a full year, but less likely than children with full-year coverage. We find comparable effects for public and private insurance. Although cross-sectional analyses suggest that transitions directly between public and private insurance are associated with lower rates of utilization, the evidence of such an effect is much weaker when we condition on child fixed effects.
Annual immunisation coverage report, 2010.

PubMed

Hull, Brynley; Dey, Aditi; Menzies, Rob; McIntyre, Peter

2013-03-31

This, the fourth annual immunisation coverage report, documents trends during 2010 for a range of standard measures derived from Australian Childhood Immunisation Register (ACIR) data. These include coverage at standard age milestones and for individual vaccines included on the National Immunisation Program (NIP). For the first time, coverage from other sources for adolescents and the elderly are included. The proportion of children 'fully vaccinated' at 12, 24 and 60 months of age was 91.6%, 92.1% and 89.1% respectively. For vaccines available on the NIP but not currently assessed for 'fully immunised' status or for eligibility for incentive payments (rotavirus and pneumococcal at 12 months and meningococcal C and varicella at 24 months) coverage varied. Although pneumococcal vaccine had similar coverage at 12 months to other vaccines, coverage was lower for rotavirus at 12 months (84.7%) and varicella at 24 months (83.0%). Overall coverage at 24 months of age exceeded that at 12 months of age nationally and for most jurisdictions, but as receipt of varicella vaccine at 18 months is excluded from calculations, this represents delayed immunisation, with some contribution from immunisation incentives. The 'fully immunised' coverage estimates for immunisations due by 60 months increased substantially in 2009, reaching almost 90% in 2010, probably related to completed immunisation by 60 months of age being introduced in 2009 as a requirement for GP incentive payments. As previously documented, vaccines recommended for Indigenous children only (hepatitis A and pneumococcal polysaccharide vaccine) had suboptimal coverage at around 57%. Delayed receipt of vaccines by Indigenous children at the 60-month milestone age improved from 56% to 62% but the disparity in on-time vaccination between Indigenous and non-Indigenous children at earlier age milestones did not improve. Coverage data for human papillomavirus (HPV)from the national HPV register are consistent with high coverage in the school-based program (73%) but were lower for the catch-up program for women outside school (30-38%). Coverage estimates for vaccines on the NIP from 65 years of age were comparable with other developed countries.
Characterizing user requirements for future land observing satellites

NASA Technical Reports Server (NTRS)

Barker, J. L.; Cressy, P. J.; Schnetzler, C. C.; Salomonson, V. V.

1981-01-01

The objective procedure was developed for identifying probable sensor and mission characteristics for an operational satellite land observing system. Requirements were systematically compiled, quantified and scored by type of use, from surveys of federal, state, local and private communities. Incremental percent increases in expected value of data were estimated for critical system improvements. Comparisons with costs permitted selection of a probable sensor system, from a set of 11 options, with the following characteristics: 30 meter spatial resolution in 5 bands and 15 meters in 1 band, spectral bands nominally at Thematic Mapper (TM) bands 1 through 6 positions, and 2 day data turn around for receipt of imagery. Improvements are suggested for both the form of questions and the procedures for analysis of future surveys in order to provide a more quantitatively precise definition of sensor and mission requirements.
Spatial distribution of epibenthic molluscs on a sandstone reef in the Northeast of Brazil.

PubMed

Martinez, A S; Mendes, L F; Leite, T S

2012-05-01

The present study investigated the distribution and abundance of epibenthic molluscs and their feeding habits associated to substrate features (coverage and rugosity) in a sandstone reef system in the Northeast of Brazil. Rugosity, low coral cover and high coverage of zoanthids and fleshy alga were the variables that influenced a low richness and high abundance of a few molluscan species in the reef habitat. The most abundant species were generalist carnivores, probably associated to a lesser offer and variability of resources in this type of reef system, when compared to the coral reefs. The results found in this study could reflect a normal characteristic of the molluscan community distribution in sandstone reefs, with low coral cover, or could indicate a degradation state of this habitat if it is compared to coral reefs, once that the significantly high coverage of fleshy alga has been recognized as a negative indicator of reef ecosystems health.
A contribution to ULF activity in the Pc 3-4 range correlated with IMF radial orientation. [geomagnetic micropulsations

NASA Technical Reports Server (NTRS)

Greenstadt, E. W.; Olson, J. V.

1977-01-01

The paper describes an experiment to determine whether the radial orientation of the interplanetary magnetic field (IMF) is associated with ULF activity in the Pc 3-4 range. Data are obtained from base levels, undisturbed intervals, IMF and disturbance selection, and trigonometric correlation. The results obtained are discussed, noting particularly that for low Kp, the probability of enhanced amplitude noise rises as IMF orientation with respect to the nominal solar wind flow decreases in both Pc 3 and Pc 4 channels.
Implications of high-spatial-resolution thermal infrared (Termoskan) data for Mars landing site selection

NASA Technical Reports Server (NTRS)

Betts, Bruce H.

1994-01-01

Thermal infrared observations of Mars from spacecraft provide physical information about the upper thermal skin depth of the surface, which is on the order of a few centimeters in depth and thus very significant for lander site selection. The Termoskan instrument onboard the Soviet Phobos '88 spacecraft acquired the highest spatial-resolution thermal infrared data obtained for Mars, ranging in resolution from 300 m to 3 km per pixel. It simultaneously obtained broadband reflected solar flux data. Although the 6 deg N - 30 deg S Termoskan coverage only slightly overlaps the nominal Mars Pathfinder target range, the implications of Termoskan data for that overlap region and the extrapolations that can be made to other regions give important clues for optimal landing site selection.
Epidemiological game-theory dynamics of chickenpox vaccination in the USA and Israel

PubMed Central

Liu, Jingzhou; Kochin, Beth F.; Tekle, Yonas I.; Galvani, Alison P.

2012-01-01

The general consensus from epidemiological game-theory studies is that vaccination coverage driven by self-interest (Nash vaccination) is generally lower than group-optimal coverage (utilitarian vaccination). However, diseases that become more severe with age, such as chickenpox, pose an exception to this general consensus. An individual choice to be vaccinated against chickenpox has the potential to harm those not vaccinated by increasing the average age at infection and thus the severity of infection as well as those already vaccinated by increasing the probability of breakthrough infection. To investigate the effects of these externalities on the relationship between Nash and utilitarian vaccination coverages for chickenpox, we developed a game-theory epidemic model that we apply to the USA and Israel, which has different vaccination programmes, vaccination and treatment costs, as well as vaccination coverage levels. We find that the increase in chickenpox severity with age can reverse the typical relationship between utilitarian and Nash vaccination coverages in both the USA and Israel. Our model suggests that to obtain herd immunity of chickenpox vaccination, subsidies or external regulation should be used if vaccination costs are high. By contrast, for low vaccination costs, improving awareness of the vaccine and the potential cost of chickenpox infection is crucial. PMID:21632611
Epidemiological game-theory dynamics of chickenpox vaccination in the USA and Israel.

PubMed

Liu, Jingzhou; Kochin, Beth F; Tekle, Yonas I; Galvani, Alison P

2012-01-07

The general consensus from epidemiological game-theory studies is that vaccination coverage driven by self-interest (Nash vaccination) is generally lower than group-optimal coverage (utilitarian vaccination). However, diseases that become more severe with age, such as chickenpox, pose an exception to this general consensus. An individual choice to be vaccinated against chickenpox has the potential to harm those not vaccinated by increasing the average age at infection and thus the severity of infection as well as those already vaccinated by increasing the probability of breakthrough infection. To investigate the effects of these externalities on the relationship between Nash and utilitarian vaccination coverages for chickenpox, we developed a game-theory epidemic model that we apply to the USA and Israel, which has different vaccination programmes, vaccination and treatment costs, as well as vaccination coverage levels. We find that the increase in chickenpox severity with age can reverse the typical relationship between utilitarian and Nash vaccination coverages in both the USA and Israel. Our model suggests that to obtain herd immunity of chickenpox vaccination, subsidies or external regulation should be used if vaccination costs are high. By contrast, for low vaccination costs, improving awareness of the vaccine and the potential cost of chickenpox infection is crucial.
Nonparametric Estimation of the Probability of Discovering a New Species.

DTIC Science & Technology

1986-01-01

see Good (1953, 1965), Good and Toulmin (1956), Goodman (1949), Harris (1959, 1968), Knott (1967) and Robbins (1968). We note that our model is not...and Toulmin , G. (1956). The number of new species and the increase of population coverage, when a sample is increased. Biometrika 43, 45-63. Goodman
Monitoring health interventions – who's afraid of LQAS?

PubMed Central

Pezzoli, Lorenzo; Kim, Sung Hye

2013-01-01

Lot quality assurance sampling (LQAS) is used to evaluate health services. Subunits of a population (lots) are accepted or rejected according to the number of failures in a random sample (N) of a given lot. If failures are greater than decision value (d), we reject the lot and recommend corrective actions in the lot (i.e. intervention area); if they are equal to or less than d, we accept it. We used LQAS to monitor coverage during the last 3 days of a meningitis vaccination campaign in Niger. We selected one health area (lot) per day reporting the lowest administrative coverage in the previous 2 days. In the sampling plan we considered: N to be small enough to allow us to evaluate one lot per day, deciding to sample 16 individuals from the selected villages of each health area, using probability proportionate to population size; thresholds and d to vary according to administrative coverage reported; α ≤5% (meaning that, if we would have conducted the survey 100 times, we would have accepted the lot up to five times when real coverage was at an unacceptable level) and β ≤20% (meaning that we would have rejected the lot up to 20 times, when real coverage was equal or above the satisfactory level). We classified all three lots as with the acceptable coverage. LQAS appeared to be a rapid, simple, and statistically sound method for in-process coverage assessment. We encourage colleagues in the field to consider using LQAS in complement with other monitoring techniques such as house-to-house monitoring. PMID:24206650
Monitoring health interventions--who's afraid of LQAS?

PubMed

Pezzoli, Lorenzo; Kim, Sung Hye

2013-11-08

Lot quality assurance sampling (LQAS) is used to evaluate health services. Subunits of a population (lots) are accepted or rejected according to the number of failures in a random sample (N) of a given lot. If failures are greater than decision value (d), we reject the lot and recommend corrective actions in the lot (i.e. intervention area); if they are equal to or less than d, we accept it. We used LQAS to monitor coverage during the last 3 days of a meningitis vaccination campaign in Niger. We selected one health area (lot) per day reporting the lowest administrative coverage in the previous 2 days. In the sampling plan we considered: N to be small enough to allow us to evaluate one lot per day, deciding to sample 16 individuals from the selected villages of each health area, using probability proportionate to population size; thresholds and d to vary according to administrative coverage reported; α ≤5% (meaning that, if we would have conducted the survey 100 times, we would have accepted the lot up to five times when real coverage was at an unacceptable level) and β ≤20% (meaning that we would have rejected the lot up to 20 times, when real coverage was equal or above the satisfactory level). We classified all three lots as with the acceptable coverage. LQAS appeared to be a rapid, simple, and statistically sound method for in-process coverage assessment. We encourage colleagues in the field to consider using LQAS in complement with other monitoring techniques such as house-to-house monitoring.
Knowledge as a Predictor of Insurance Coverage Under the Affordable Care Act.

PubMed

Hoerl, Maximiliane; Wuppermann, Amelie; Barcellos, Silvia H; Bauhoff, Sebastian; Winter, Joachim K; Carman, Katherine G

2017-04-01

The Affordable Care Act established policy mechanisms to increase health insurance coverage in the United States. While insurance coverage has increased, 10%-15% of the US population remains uninsured. To assess whether health insurance literacy and financial literacy predict being uninsured, covered by Medicaid, or covered by Marketplace insurance, holding demographic characteristics, attitudes toward risk, and political affiliation constant. Analysis of longitudinal data from fall 2013 and spring 2015 including financial and health insurance literacy and key covariates collected in 2013. A total of 2742 US residents ages 18-64, 525 uninsured in fall 2013, participating in the RAND American Life Panel, a nationally representative internet panel. Self-reported health insurance status and type as of spring 2015. Among the uninsured in 2013, higher financial and health insurance literacy were associated with greater probability of being insured in 2015. For a typical uninsured individual in 2013, the probability of being insured in 2015 was 8.3 percentage points higher with high compared with low financial literacy, and 9.2 percentage points higher with high compared with low health insurance literacy. For the general population, those with high financial and health insurance literacy were more likely to obtain insurance through Medicaid or the Marketplaces compared with being uninsured. The magnitude of coefficients for these predictors was similar to that of commonly used demographic covariates. A lack of understanding about health insurance concepts and financial illiteracy predict who remains uninsured. Outreach and consumer-education programs should consider these characteristics.
Pediatric ambulatory care sensitive conditions: Birth cohorts and the socio-economic gradient.

PubMed

Roos, Leslie L; Dragan, Roxana; Schroth, Robert J

2017-09-14

This study examines the socio-economic gradient in utilization and the risk factors associated with hospitalization for four pediatric ambulatory care sensitive conditions (dental conditions, asthma, gastroenteritis, and bacterial pneumonia). Dental conditions, where much care is provided by dentists and insurance coverage varies among different population segments, present special issues. A population registry, provider registry, physician ambulatory claims, and hospital discharge abstracts from 28 398 children born in 2003-2006 in urban centres in Manitoba, Canada were the main data sources. Physician visits and hospitalizations were compared across neighbourhood income groupings using rank correlations and logistic regressions. Very strong relationships between neighbourhood income and utilization were highlighted. Additional variables - family on income assistance, mother's age at first birth, breastfeeding - helped predict the probability of hospitalization. Despite the complete insurance coverage (including visits to dentists and physicians and for hospitalizations) provided, receiving income assistance was associated with higher probabilities of hospitalization. We found a socio-economic gradient in utilization for pediatric ambulatory care sensitive conditions, with higher rates of ambulatory visits and hospitalizations in the poorest neighbourhoods. Insurance coverage which varies between different segments of the population complicates matters. Providing funding for dental care for Manitobans on income assistance has not prevented physician visits or intensive treatment in high-cost facilities, specifically treatment under general anesthesia. When services from one type of provider (dentist) are not universally insured but those from another type (physician) are, using rates of hospitalization to indicate problems in the organization of care seems particularly difficult.

Effects of healthcare reforms on coverage, access, and disparities: quasi-experimental analysis of evidence from Massachusetts.

PubMed

Pande, Aakanksha H; Ross-Degnan, Dennis; Zaslavsky, Alan M; Salomon, Joshua A

2011-07-01

The 2010 Patient Protection and Affordable Care Act (PPACA) has been controversial. The potential impact of national healthcare reform may be considered using a similar set of state-level reforms including exchanges and a mandate, enacted in 2006 in Massachusetts. To evaluate the effects of reforms on healthcare access, affordability, and disparities. Interrupted time series with comparison series. Longitudinal survey data from 2002 to 2009 from the Behavioral Risk Factor Surveillance System including 178,040 nonelderly adults residing in Massachusetts, Vermont, New Hampshire, Rhode Island, and Connecticut. Analysis was conducted from January to August 2010. Massachusetts 2006 healthcare reform, which included an individual health insurance mandate. Being uninsured, having no personal doctor, and forgoing care because of cost, evaluated in Massachusetts and four comparison states before (2002-2005) and after (2007-2009) the healthcare reform. Effects on disparities defined by race, education, income, and employment also were assessed. Living in Massachusetts in 2009 was associated with a 7.6 percentage point (95% CI=3.9, 11.3) higher probability of being insured; 4.8 percentage point (-0.9, 10.6) lower probability of forgoing care because of cost; and a 6.6 percentage point (1.9, 11.3) higher probability of having a personal doctor, compared to expected levels in the absence of reform, defined by trends in control states and adjusting for socioeconomic factors. The effects of the reform on insurance coverage attenuated from 2008 to 2009. In a socioeconomically disadvantaged group, the reforms had a greater effect in improving outcomes on the absolute but not relative scale. Healthcare reforms in Massachusetts, which included a health insurance mandate, were associated with significant increases in insurance coverage and access. The absolute effects of the reform were greater for disadvantaged populations. This is important evidence to consider as debate over national healthcare reform continues. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.
Hospital Utilization and Universal Health Insurance Coverage: Evidence from the Massachusetts Health Care Reform Act.

PubMed

Cseh, Attila; Koford, Brandon C; Phelps, Ryan T

2015-12-01

The Affordable Care Act is currently in the roll-out phase. To gauge the likely implications of the national policy we analyze how the Massachusetts Health Care Reform Act impacted various hospitalization outcomes in each of the 25 major diagnostic categories (MDC). We utilize a difference-in-difference approach to identify the impact of the Massachusetts reform on insurance coverage and patient outcomes. This identification is achieved using six years of data from the Nationwide Inpatient Sample from the Healthcare Cost and Utilization Project. We report MDC-specific estimates of the impact of the reform on insurance coverage and type as well as length of stay, number of diagnoses, and number of procedures. The requirement of universal insurance coverage increased the probability of being covered by insurance. This increase was in part a result of an increase in the probability of being covered by Medicaid. The percentage of admissions covered by private insurance fell. The number of diagnoses rose as a result of the law in the vast majority of diagnostic categories. Our results related to length of stay suggest that looking at aggregate results hides a wealth of information. The most disparate outcomes were pregnancy related. The length of stay for new-born babies and neonates rose dramatically. In aggregate, this increase serves to mute decreases across other diagnoses. Also, the number of procedures fell within the MDCs for pregnancy and child birth and that for new-born babies and neonates. The Massachusetts Health Care Reform appears to have been effective at increasing insurance take-up rates. These increases may have come at the cost of lower private insurance coverage. The number of diagnoses per admission was increased by the policy across nearly all MDCs. Understanding the changes in length of stay as a result of the Massachusetts reform, and perhaps the Affordable Care Act, requires MDC-specific analysis. It appears that the most important distinction to make is to differentiate care related to new-born babies and neonates from that related to other diagnostic categories.
Preliminary Axial Flow Turbine Design and Off-Design Performance Analysis Methods for Rotary Wing Aircraft Engines. Part 2; Applications

NASA Technical Reports Server (NTRS)

Chen, Shu-cheng, S.

2009-01-01

In this paper, preliminary studies on two turbine engine applications relevant to the tilt-rotor rotary wing aircraft are performed. The first case-study is the application of variable pitch turbine for the turbine performance improvement when operating at a substantially lower shaft speed. The calculations are made on the 75 percent speed and the 50 percent speed of operations. Our results indicate that with the use of the variable pitch turbines, a nominal (3 percent (probable) to 5 percent (hypothetical)) efficiency improvement at the 75 percent speed, and a notable (6 percent (probable) to 12 percent (hypothetical)) efficiency improvement at the 50 percent speed, without sacrificing the turbine power productions, are achievable if the technical difficulty of turning the turbine vanes and blades can be circumvented. The second casestudy is the contingency turbine power generation for the tilt-rotor aircraft in the One Engine Inoperative (OEI) scenario. For this study, calculations are performed on two promising methods: throttle push and steam injection. By isolating the power turbine and limiting its air mass flow rate to be no more than the air flow intake of the take-off operation, while increasing the turbine inlet total temperature (simulating the throttle push) or increasing the air-steam mixture flow rate (simulating the steam injection condition), our results show that an amount of 30 to 45 percent extra power, to the nominal take-off power, can be generated by either of the two methods. The methods of approach, the results, and discussions of these studies are presented in this paper.
Improving online risk assessment with equipment prognostics and health monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coble, Jamie B.; Liu, Xiaotong; Briere, Chris

The current approach to evaluating the risk of nuclear power plant (NPP) operation relies on static probabilities of component failure, which are based on industry experience with the existing fleet of nominally similar light water reactors (LWRs). As the nuclear industry looks to advanced reactor designs that feature non-light water coolants (e.g., liquid metal, high temperature gas, molten salt), this operating history is not available. Many advanced reactor designs use advanced components, such as electromagnetic pumps, that have not been used in the US commercial nuclear fleet. Given the lack of rich operating experience, we cannot accurately estimate the evolvingmore » probability of failure for basic components to populate the fault trees and event trees that typically comprise probabilistic risk assessment (PRA) models. Online equipment prognostics and health management (PHM) technologies can bridge this gap to estimate the failure probabilities for components under operation. The enhanced risk monitor (ERM) incorporates equipment condition assessment into the existing PRA and risk monitor framework to provide accurate and timely estimates of operational risk.« less
How autonomy and the web are taking the people out of TacSat-2

NASA Astrophysics Data System (ADS)

Finley, Charles J.

2006-05-01

One of the most costly components of the on-orbit operation of a spacecraft is the people that execute the mission. Historically, for Air Force Research Laboratory (AFRL) and the Department of Defense Space Test Program (STP) research and development, test and evaluation (RDT&E) space missions, a team of fifteen personnel maintains 24-hour coverage for the three-week Launch and Early Operations (L/EO) phase of the mission and four one-week L/EO rehearsals. During the Nominal Operations phase of the mission, 2.5 "man-days" of support are necessary each day that the spacecraft remains on-orbit, as well as during the two, week-long, nominal operations rehearsals. Therefore, the mission-dedicated personnel contribution to the cost of a one-year mission is more than eleven man-years, and this does not include the personnel that actually operate the antennas at the various remote ground facilities or develop and maintain the mission-specific or shared-use ground network, hardware, and software. In the low-budget RDT&E world, hardware, software, or Concept of Operations (CONOPS) developments that significantly reduce the necessary Operations personnel investment can mean the difference between a mission that does or does not survive. This paper explores the CONOPS and suite of tools that the TacSat-2 program has put together to achieve maximum mission effectiveness at minimum manpower cost.
Using Social Network Methods to Test for Assortment of Prosociality among Korean High School Students.

PubMed

Kim, Jun-Hong; Holman, Darryl J; Goodreau, Steven M

2015-01-01

Assortative interaction among altruistic individuals is a necessary condition for the evolution of cooperation. The requirement for assortment holds regardless of whether a meta-population is subdivided into distinct and isolated subgroups or has ephemeral boundaries with a high migration rate. The assumption, however, is rarely tested directly. In this paper, we develop a method to test for assortment of prosociality in network-structured data. The method is applied to a friendship network collected from 238 Korean students attending the same high school. A mixing matrix was used to explore the presence of assortative friendship among more prosocial individuals. An exponential random graph model of network structure that accounts for additional observed relational propensities (higher-than-expected number of people nominating no friends) and sampling constraints (upper bound on friendship nominations) found that individual prosociality predicted friendship propensity, and that individuals with higher prosocial scores had a higher probability of befriending other more prosocial individuals. The results reveal that a considerable level of assortment of prosociality characterizes this population.
The detection of fatigue cracks by nondestructive testing methods

NASA Technical Reports Server (NTRS)

Rummel, W. D.; Todd, P. H., Jr.; Frecska, S. A.; Rathke, R. A.

1974-01-01

X-radiographic penetrant, ultrasonic, eddy current, holographic, and acoustic emission techniques were optimized and applied to the evaluation of 2219-T87 aluminum alloy test specimens. One hundred eighteen specimens containing a total of 328 fatigue cracks were evaluated. The cracks ranged in length from 0.500 inch (1.27 cm) to 0.007 inch (0.018 cm) and in depth from 0.178 inch (0.451 cm) and 0.001 inch (0.003 cm). Specimen thicknesses were nominally 0.060 inch (0.152 cm) and 0.210 inch (0.532 cm) and surface finishes were nominally 32 and 125 rms and 64 and 200 rms respectively. Specimens were evaluated in the as-milled surface condition, in the chemically milled surface condition and, after proof loading, in a randomized inspection sequence. Results of the nondestructive test (NDT) evaluations were compared with actual crack size obtained by measurement of the fractured specimens. Inspection data was then analyzed to provide a statistical basis for determinating the threshold crack detection sensitivity (the largest crack size that would be missed) for each of the inspection techniques at a 95% probability and 95% confidence level.
Using Social Network Methods to Test for Assortment of Prosociality among Korean High School Students

PubMed Central

Kim, Jun-Hong; Holman, Darryl J.; Goodreau, Steven M.

2015-01-01

Assortative interaction among altruistic individuals is a necessary condition for the evolution of cooperation. The requirement for assortment holds regardless of whether a meta-population is subdivided into distinct and isolated subgroups or has ephemeral boundaries with a high migration rate. The assumption, however, is rarely tested directly. In this paper, we develop a method to test for assortment of prosociality in network-structured data. The method is applied to a friendship network collected from 238 Korean students attending the same high school. A mixing matrix was used to explore the presence of assortative friendship among more prosocial individuals. An exponential random graph model of network structure that accounts for additional observed relational propensities (higher-than-expected number of people nominating no friends) and sampling constraints (upper bound on friendship nominations) found that individual prosociality predicted friendship propensity, and that individuals with higher prosocial scores had a higher probability of befriending other more prosocial individuals. The results reveal that a considerable level of assortment of prosociality characterizes this population. PMID:25915508
Different preferences or different opportunities? Explaining race differentials in the academic achievement of friends

PubMed Central

Flashman, Jennifer

2015-01-01

A popular explanation for race and ethnic disparities in academic achievement is that minorities are exposed to different peers and have different opportunities to make friends with high-achievers. Although we know that adolescents from different race and ethnic groups attend different schools and that they choose different friends, we do not know how these different opportunities affect the friends they make. This paper fills this gap by studying how the opportunities within adolescents’ schools affect race and ethnic differences in the academic characteristics of friends. Using data from the National Longitudinal Study of Adolescent Health and the conditional logit and opportunities framework, I account for adolescents’ different opportunities to make friends both within and across schools. Ignoring their different opportunities, Black and Latino adolescents’ nominated friends have significantly lower levels of achievement than white adolescents. After accounting for their different opportunities to make friends within and between schools, race and ethnic differences in the achievement characteristics of friends disappear. If Black and Latino adolescents’ opportunity structures were identical to white adolescents’, their probabilities of nominating high-achieving friends would not differ. PMID:23017858
Statistical analysis of the limitation of half integer resonances on the available momentum acceptance of the High Energy Photon Source

NASA Astrophysics Data System (ADS)

Jiao, Yi; Duan, Zhe

2017-01-01

In a diffraction-limited storage ring, half integer resonances can have strong effects on the beam dynamics, associated with the large detuning terms from the strong focusing and strong sextupoles as required for an ultralow emittance. In this study, the limitation of half integer resonances on the available momentum acceptance (MA) was statistically analyzed based on one design of the High Energy Photon Source (HEPS). It was found that the probability of MA reduction due to crossing of half integer resonances is closely correlated with the level of beta beats at the nominal tunes, but independent of the error sources. The analysis indicated that for the presented HEPS lattice design, the rms amplitude of beta beats should be kept below 1.5% horizontally and 2.5% vertically to reach a small MA reduction probability of about 1%.
Structure of a quasi-parallel, quasi-laminar bow shock

NASA Technical Reports Server (NTRS)

Greenstadt, E. W.; Russell, C. T.; Formisano, V.; Hedgecock, P. C.; Scarf, F. L.; Neugebauer, M.; Holzer, R. E.

1976-01-01

A thick, quasi-parallel bow shock structure was observed with field and particle detectors of both HEOS 1 and OGO 5. The typical magnetic pulsation structure was at least 1 to 2 earth radii thick radially and was accompanied by irregular but distinct plasma distributions characteristic of neither the solar wind nor the magnetosheath. Waves constituting the large pulsations were polarized principally in the plane of the nominal shock, therefore also in the plane perpendicular to the average interplanetary field. A separate interpulsation regime detected between bursts of large amplitude oscillations was similar to the upstream wave region magnetically, but was characterized by disturbed plasma flux and enhanced noise around the ion plasma frequency. The shock structure appeared to be largely of an oblique, whistler type, probably complicated by counterstreaming high energy protons. Evidence for firehose instability-based structure was weak at best and probably negative.
A goodness-of-fit test for capture-recapture model M(t) under closure

USGS Publications Warehouse

Stanley, T.R.; Burnham, K.P.

1999-01-01

A new, fully efficient goodness-of-fit test for the time-specific closed-population capture-recapture model M(t) is presented. This test is based on the residual distribution of the capture history data given the maximum likelihood parameter estimates under model M(t), is partitioned into informative components, and is based on chi-square statistics. Comparison of this test with Leslie's test (Leslie, 1958, Journal of Animal Ecology 27, 84- 86) for model M(t), using Monte Carlo simulations, shows the new test generally outperforms Leslie's test. The new test is frequently computable when Leslie's test is not, has Type I error rates that are closer to nominal error rates than Leslie's test, and is sensitive to behavioral variation and heterogeneity in capture probabilities. Leslie's test is not sensitive to behavioral variation in capture probabilities but, when computable, has greater power to detect heterogeneity than the new test.
A new methodology to integrate planetary quarantine requirements into mission planning, with application to a Jupiter orbiter

NASA Technical Reports Server (NTRS)

Howard, R. A.; North, D. W.; Pezier, J. P.

1975-01-01

A new methodology is proposed for integrating planetary quarantine objectives into space exploration planning. This methodology is designed to remedy the major weaknesses inherent in the current formulation of planetary quarantine requirements. Application of the methodology is illustrated by a tutorial analysis of a proposed Jupiter Orbiter mission. The proposed methodology reformulates planetary quarantine planning as a sequential decision problem. Rather than concentrating on a nominal plan, all decision alternatives and possible consequences are laid out in a decision tree. Probabilities and values are associated with the outcomes, including the outcome of contamination. The process of allocating probabilities, which could not be made perfectly unambiguous and systematic, is replaced by decomposition and optimization techniques based on principles of dynamic programming. Thus, the new methodology provides logical integration of all available information and allows selection of the best strategy consistent with quarantine and other space exploration goals.
A Nested Phosphorus and Proton Coil Array for Brain Magnetic Resonance Imaging and Spectroscopy

PubMed Central

Brown, Ryan; Lakshmanan, Karthik; Madelin, Guillaume; Parasoglou, Prodromos

2015-01-01

A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7 Tesla. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4 cm nominal isotropic resolution in 15 min (2.3 cm actual resolution), while additionally enabling 1 mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer’s and Parkinson’s diseases, as well as mental disorders such as schizophrenia. PMID:26375209
A nested phosphorus and proton coil array for brain magnetic resonance imaging and spectroscopy.

PubMed

Brown, Ryan; Lakshmanan, Karthik; Madelin, Guillaume; Parasoglou, Prodromos

2016-01-01

A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7T. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4cm nominal isotropic resolution in 15min (2.3cm actual resolution), while additionally enabling 1mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases, as well as mental disorders such as schizophrenia. Copyright © 2015 Elsevier Inc. All rights reserved.
Adaptive pre-specification in randomized trials with and without pair-matching.

PubMed

Balzer, Laura B; van der Laan, Mark J; Petersen, Maya L

2016-11-10

In randomized trials, adjustment for measured covariates during the analysis can reduce variance and increase power. To avoid misleading inference, the analysis plan must be pre-specified. However, it is often unclear a priori which baseline covariates (if any) should be adjusted for in the analysis. Consider, for example, the Sustainable East Africa Research in Community Health (SEARCH) trial for HIV prevention and treatment. There are 16 matched pairs of communities and many potential adjustment variables, including region, HIV prevalence, male circumcision coverage, and measures of community-level viral load. In this paper, we propose a rigorous procedure to data-adaptively select the adjustment set, which maximizes the efficiency of the analysis. Specifically, we use cross-validation to select from a pre-specified library the candidate targeted maximum likelihood estimator (TMLE) that minimizes the estimated variance. For further gains in precision, we also propose a collaborative procedure for estimating the known exposure mechanism. Our small sample simulations demonstrate the promise of the methodology to maximize study power, while maintaining nominal confidence interval coverage. We show how our procedure can be tailored to the scientific question (intervention effect for the study sample vs. for the target population) and study design (pair-matched or not). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Assessing Interval Estimation Methods for Hill Model ...

EPA Pesticide Factsheets

The Hill model of concentration-response is ubiquitous in toxicology, perhaps because its parameters directly relate to biologically significant metrics of toxicity such as efficacy and potency. Point estimates of these parameters obtained through least squares regression or maximum likelihood are commonly used in high-throughput risk assessment, but such estimates typically fail to include reliable information concerning confidence in (or precision of) the estimates. To address this issue, we examined methods for assessing uncertainty in Hill model parameter estimates derived from concentration-response data. In particular, using a sample of ToxCast concentration-response data sets, we applied four methods for obtaining interval estimates that are based on asymptotic theory, bootstrapping (two varieties), and Bayesian parameter estimation, and then compared the results. These interval estimation methods generally did not agree, so we devised a simulation study to assess their relative performance. We generated simulated data by constructing four statistical error models capable of producing concentration-response data sets comparable to those observed in ToxCast. We then applied the four interval estimation methods to the simulated data and compared the actual coverage of the interval estimates to the nominal coverage (e.g., 95%) in order to quantify performance of each of the methods in a variety of cases (i.e., different values of the true Hill model paramet
Joint modelling compared with two stage methods for analysing longitudinal data and prospective outcomes: A simulation study of childhood growth and BP.

PubMed

Sayers, A; Heron, J; Smith, Adac; Macdonald-Wallis, C; Gilthorpe, M S; Steele, F; Tilling, K

2017-02-01

There is a growing debate with regards to the appropriate methods of analysis of growth trajectories and their association with prospective dependent outcomes. Using the example of childhood growth and adult BP, we conducted an extensive simulation study to explore four two-stage and two joint modelling methods, and compared their bias and coverage in estimation of the (unconditional) association between birth length and later BP, and the association between growth rate and later BP (conditional on birth length). We show that the two-stage method of using multilevel models to estimate growth parameters and relating these to outcome gives unbiased estimates of the conditional associations between growth and outcome. Using simulations, we demonstrate that the simple methods resulted in bias in the presence of measurement error, as did the two-stage multilevel method when looking at the total (unconditional) association of birth length with outcome. The two joint modelling methods gave unbiased results, but using the re-inflated residuals led to undercoverage of the confidence intervals. We conclude that either joint modelling or the simpler two-stage multilevel approach can be used to estimate conditional associations between growth and later outcomes, but that only joint modelling is unbiased with nominal coverage for unconditional associations.
Effect Sizes and their Intervals: The Two-Level Repeated Measures Case

ERIC Educational Resources Information Center

Algina, James; Keselman, H. J.; Penfield, Randall D.

2005-01-01

Probability coverage for eight different confidence intervals (CIs) of measures of effect size (ES) in a two-level repeated measures design was investigated. The CIs and measures of ES differed with regard to whether they used least squares or robust estimates of central tendency and variability, whether the end critical points of the interval…
Does the Availability of Parental Health Insurance Affect the College Enrollment Decision of Young Americans?

ERIC Educational Resources Information Center

Jung, Juergen; Hall, Diane M. Harnek; Rhoads, Thomas

2013-01-01

The present study examines whether the college enrollment decision of young individuals (student full-time, student part-time, and non-student) depends on health insurance coverage via a parent's family health plan. Our findings indicate that the availability of parental health insurance can have significant effects on the probability that a young…

Optimal and Most Exact Confidence Intervals for Person Parameters in Item Response Theory Models

ERIC Educational Resources Information Center

Doebler, Anna; Doebler, Philipp; Holling, Heinz

2013-01-01

The common way to calculate confidence intervals for item response theory models is to assume that the standardized maximum likelihood estimator for the person parameter [theta] is normally distributed. However, this approximation is often inadequate for short and medium test lengths. As a result, the coverage probabilities fall below the given…
Carlsberg alibi marketing in the UEFA euro 2016 football finals: implications of Probably inappropriate alcohol advertising.

PubMed

Murray, Rachael; Breton, Magdalena Opazo; Britton, John; Cranwell, Jo; Grant-Braham, Bruce

2018-04-25

Alcohol advertising is a key driver of alcohol consumption, and is prohibited in France by the Loi Evin. In 2016 the Danish brewer Carlsberg sponsored the UEFA Euro 2016 finals, held in France, and used the alibis 'Probably' and '…the best in the world' in place of Carlsberg in pitch-side advertising. We have quantified the advertising exposure achieved during the final seven games in the UEFA Euro 2016 championship. Appearances of the Carlsberg alibis 'Probably' and 'the best in the world' were counted and timed to the nearest second during all active play in live coverage of quarter final, semi-final and final matches broadcast in the UK. We used census data and viewing figures from Kantar Media to estimate gross and per capita impressions of these advertisements in the UK population. In 796 min, 29 s of active play there were 746 alibi appearances, totalling 68 min 35 s duration and representing 8.6% of active playing time. Appearances were particularly frequent at the end of normal time, extra time and penalties. The seven matches delivered up to 7.43 billion Carlsberg alibi impressions to UK adults and 163.3 million to children. In the only match involving a second country with laws prohibiting alcohol advertising (France versus Iceland), exposure occurred for only 1.8% of playing time. Alibi marketing achieved significant advertising coverage during the final seven EURO 2016 championship games, particularly to children. Since 'Probably' is registered by Carlsberg as a wordmark this advertising appears to contravene the Loi Evin, though Carlsberg have defended their marketing actions.
Optimal strategy for polarization modulation in the LSPE-SWIPE experiment

NASA Astrophysics Data System (ADS)

Buzzelli, A.; de Bernardis, P.; Masi, S.; Vittorio, N.; de Gasperis, G.

2018-01-01

Context. Cosmic microwave background (CMB) B-mode experiments are required to control systematic effects with an unprecedented level of accuracy. Polarization modulation by a half wave plate (HWP) is a powerful technique able to mitigate a large number of the instrumental systematics. Aims: Our goal is to optimize the polarization modulation strategy of the upcoming LSPE-SWIPE balloon-borne experiment, devoted to the accurate measurement of CMB polarization at large angular scales. Methods: We departed from the nominal LSPE-SWIPE modulation strategy (HWP stepped every 60 s with a telescope scanning at around 12 deg/s) and performed a thorough investigation of a wide range of possible HWP schemes (either in stepped or continuously spinning mode and at different azimuth telescope scan-speeds) in the frequency, map and angular power spectrum domain. In addition, we probed the effect of high-pass and band-pass filters of the data stream and explored the HWP response in the minimal case of one detector for one operation day (critical for the single-detector calibration process). We finally tested the modulation performance against typical HWP-induced systematics. Results: Our analysis shows that some stepped HWP schemes, either slowly rotating or combined with slow telescope modulations, represent poor choices. Moreover, our results point out that the nominal configuration may not be the most convenient choice. While a large class of spinning designs provides comparable results in terms of pixel angle coverage, map-making residuals and BB power spectrum standard deviations with respect to the nominal strategy, we find that some specific configurations (e.g., a rapidly spinning HWP with a slow gondola modulation) allow a more efficient polarization recovery in more general real-case situations. Conclusions: Although our simulations are specific to the LSPE-SWIPE mission, the general outcomes of our analysis can be easily generalized to other CMB polarization experiments.
Orbit Determination Error Analysis Results for the Triana Sun-Earth L2 Libration Point Mission

NASA Technical Reports Server (NTRS)

Marr, G.

2003-01-01

Using the NASA Goddard Space Flight Center's Orbit Determination Error Analysis System (ODEAS), orbit determination error analysis results are presented for all phases of the Triana Sun-Earth L1 libration point mission and for the science data collection phase of a future Sun-Earth L2 libration point mission. The Triana spacecraft was nominally to be released by the Space Shuttle in a low Earth orbit, and this analysis focuses on that scenario. From the release orbit a transfer trajectory insertion (TTI) maneuver performed using a solid stage would increase the velocity be approximately 3.1 km/sec sending Triana on a direct trajectory to its mission orbit. The Triana mission orbit is a Sun-Earth L1 Lissajous orbit with a Sun-Earth-vehicle (SEV) angle between 4.0 and 15.0 degrees, which would be achieved after a Lissajous orbit insertion (LOI) maneuver at approximately launch plus 6 months. Because Triana was to be launched by the Space Shuttle, TTI could potentially occur over a 16 orbit range from low Earth orbit. This analysis was performed assuming TTI was performed from a low Earth orbit with an inclination of 28.5 degrees and assuming support from a combination of three Deep Space Network (DSN) stations, Goldstone, Canberra, and Madrid and four commercial Universal Space Network (USN) stations, Alaska, Hawaii, Perth, and Santiago. These ground stations would provide coherent two-way range and range rate tracking data usable for orbit determination. Larger range and range rate errors were assumed for the USN stations. Nominally, DSN support would end at TTI+144 hours assuming there were no USN problems. Post-TTI coverage for a range of TTI longitudes for a given nominal trajectory case were analyzed. The orbit determination error analysis after the first correction maneuver would be generally applicable to any libration point mission utilizing a direct trajectory.
Theoretical aspects of studies of high coverage oxidation of the Cu(100) surface using low energy positrons

NASA Astrophysics Data System (ADS)

Fazleev, N. G.; Maddox, W. B.; Reed, J. A.

2011-03-01

The study of adsorption of oxygen on transition metal surface is important for the understanding of oxidation, heterogeneous catalysis, and metal corrosion. The structures formed on transition metal surfaces vary from simple adlayers of chemisorbed oxygen to more complex structures which results from diffusion of oxygen into the sub-surface regions. In this work we present the results of an ab-initio investigation of positron surface and bulk states and annihilation probabilities of surface-trapped positrons with relevant core electrons at the Cu(100) missing row reconstructed surface under conditions of high oxygen coverage. Calculations are performed for various surface and subsurface oxygen coverages ranging from 0.50 to 1.50 monolayers. Calculations are also performed for the on-surface adsorption of oxygen on the unreconstructed Cu(001) surface for coverages up to one monolayer to use for comparison. Estimates of the positron binding energy, positron work function, and annihilation characteristics reveal their sensitivity to atomic structure of the topmost layers of the surface and charge transfer. Theoretical results are compared with experimental data obtained from studies of oxidation of the Cu(100) surface using positron annihilation induced Auger electron spectroscopy.
Achieving Crossed Strong Barrier Coverage in Wireless Sensor Network.

PubMed

Han, Ruisong; Yang, Wei; Zhang, Li

2018-02-10

Barrier coverage has been widely used to detect intrusions in wireless sensor networks (WSNs). It can fulfill the monitoring task while extending the lifetime of the network. Though barrier coverage in WSNs has been intensively studied in recent years, previous research failed to consider the problem of intrusion in transversal directions. If an intruder knows the deployment configuration of sensor nodes, then there is a high probability that it may traverse the whole target region from particular directions, without being detected. In this paper, we introduce the concept of crossed barrier coverage that can overcome this defect. We prove that the problem of finding the maximum number of crossed barriers is NP-hard and integer linear programming (ILP) is used to formulate the optimization problem. The branch-and-bound algorithm is adopted to determine the maximum number of crossed barriers. In addition, we also propose a multi-round shortest path algorithm (MSPA) to solve the optimization problem, which works heuristically to guarantee efficiency while maintaining near-optimal solutions. Several conventional algorithms for finding the maximum number of disjoint strong barriers are also modified to solve the crossed barrier problem and for the purpose of comparison. Extensive simulation studies demonstrate the effectiveness of MSPA.
Hold it! The influence of lingering rewards on choice diversification and persistence.

PubMed

Schulze, Christin; van Ravenzwaaij, Don; Newell, Ben R

2017-11-01

Learning to choose adaptively when faced with uncertain and variable outcomes is a central challenge for decision makers. This study examines repeated choice in dynamic probability learning tasks in which outcome probabilities changed either as a function of the choices participants made or independently of those choices. This presence/absence of sequential choice-outcome dependencies was implemented by manipulating a single task aspect between conditions: the retention/withdrawal of reward across individual choice trials. The study addresses how people adapt to these learning environments and to what extent they engage in 2 choice strategies often contrasted as paradigmatic examples of striking violation of versus nominal adherence to rational choice: diversification and persistent probability maximizing, respectively. Results show that decisions approached adaptive choice diversification and persistence when sufficient feedback was provided on the dynamic rules of the probabilistic environments. The findings of divergent behavior in the 2 environments indicate that diversified choices represented a response to the reward retention manipulation rather than to the mere variability of outcome probabilities. Choice in both environments was well accounted for by the generalized matching law, and computational modeling-based strategy analyses indicated that adaptive choice arose mainly from reliance on reinforcement learning strategies. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
The Effect of the Affordable Care Act's Young Adult Insurance Expansions on Hospital-Based Behavioral Health Care

PubMed Central

Golberstein, Ezra; Busch, Susan H.; Zaha, Rebecca; Greenfield, Shelly F.; Beardslee, William R.; Meara, Ellen

2014-01-01

Objective Insurance coverage for young adults has increased since 2010, when the Affordable Care Act (ACA) required insurers to permit children on parental policies until age 26 as dependents. This study estimated changes in young adults’ use of hospital-based services with diagnosis codes for mental illness and substance abuse associated with the dependent coverage provision. Method Quasi-experimental comparison of national sample of non-birth hospital inpatient admissions to general hospitals (n=2,670,463 total, n=430,583 with primary behavioral health diagnosis) and California emergency department (ED) visits with behavioral health diagnoses (n=11,139,689). Data spanned 2005 to 2011. Estimates compared young adults who were and were not targeted by the ACA dependent coverage provision (19 to 25 versus 26 to 29 year olds), estimating changes in utilization before and after 2010. Primary outcomes included: quarterly inpatient admissions for primary diagnosis of any behavioral health disorder per 1000 population; ED visits with any behavioral health diagnosis per 1000 population; and payer source. Results Dependent coverage expansion was associated with 0.14 per 1000 more (p<0.001) inpatient admissions for behavioral health for 19-25 (ACA covered) versus 26-29 (then ACA uncovered) year olds. The coverage expansion was associated with 0.45 fewer behavioral health ED visits per 1000 (p=0.001) in California. The probability that inpatient admissions nationally, and ED visits in California were uninsured, decreased significantly (p<0.001). Conclusions ACA dependent coverage provisions produced modest increases in general hospital psychiatric inpatient admissions and higher rates of insurance coverage for young adult children nationally. Lower ED visit rates were observed in California. PMID:25263817
A longitudinal study of medicaid coverage for tobacco dependence treatments in Massachusetts and associated decreases in hospitalizations for cardiovascular disease.

PubMed

Land, Thomas; Rigotti, Nancy A; Levy, Douglas E; Paskowsky, Mark; Warner, Donna; Kwass, Jo-Ann; Wetherell, Leann; Keithly, Lois

2010-12-07

Insurance coverage of tobacco cessation medications increases their use and reduces smoking prevalence in a population. However, uncertainty about the impact of this coverage on health care utilization and costs is a barrier to the broader adoption of this policy, especially by publicly funded state Medicaid insurance programs. Whether a publicly funded tobacco cessation benefit leads to decreased medical claims for tobacco-related diseases has not been studied. We examined the experience of Massachusetts, whose Medicaid program adopted comprehensive coverage of tobacco cessation medications in July 2006. Over 75,000 Medicaid subscribers used the benefit in the first 2.5 years. On the basis of earlier secondary survey work, it was estimated that smoking prevalence declined among subscribers by 10% during this period. Using claims data, we compared the probability of hospitalization prior to use of the tobacco cessation pharmacotherapy benefit with the probability of hospitalization after benefit use among Massachusetts Medicaid beneficiaries, adjusting for demographics, comorbidities, seasonality, influenza cases, and the implementation of the statewide smoke-free air law using generalized estimating equations. Statistically significant annualized declines of 46% (95% confidence interval 2%-70%) and 49% (95% confidence interval 6%-72%) were observed in hospital admissions for acute myocardial infarction and other acute coronary heart disease diagnoses, respectively. There were no significant decreases in hospitalizations rates for respiratory diagnoses or seven other diagnostic groups evaluated. Among Massachusetts Medicaid subscribers, use of a comprehensive tobacco cessation pharmacotherapy benefit was associated with a significant decrease in claims for hospitalizations for acute myocardial infarction and acute coronary heart disease, but no significant change in hospital claims for other diagnoses. For low-income smokers, removing the barriers to the use of smoking cessation pharmacotherapy has the potential to decrease short-term utilization of hospital services.
A Longitudinal Study of Medicaid Coverage for Tobacco Dependence Treatments in Massachusetts and Associated Decreases in Hospitalizations for Cardiovascular Disease

PubMed Central

Land, Thomas; Rigotti, Nancy A.; Levy, Douglas E.; Paskowsky, Mark; Warner, Donna; Kwass, Jo-Ann; Wetherell, LeAnn; Keithly, Lois

2010-01-01

Background Insurance coverage of tobacco cessation medications increases their use and reduces smoking prevalence in a population. However, uncertainty about the impact of this coverage on health care utilization and costs is a barrier to the broader adoption of this policy, especially by publicly funded state Medicaid insurance programs. Whether a publicly funded tobacco cessation benefit leads to decreased medical claims for tobacco-related diseases has not been studied. We examined the experience of Massachusetts, whose Medicaid program adopted comprehensive coverage of tobacco cessation medications in July 2006. Over 75,000 Medicaid subscribers used the benefit in the first 2.5 years. On the basis of earlier secondary survey work, it was estimated that smoking prevalence declined among subscribers by 10% during this period. Methods and Findings Using claims data, we compared the probability of hospitalization prior to use of the tobacco cessation pharmacotherapy benefit with the probability of hospitalization after benefit use among Massachusetts Medicaid beneficiaries, adjusting for demographics, comorbidities, seasonality, influenza cases, and the implementation of the statewide smoke-free air law using generalized estimating equations. Statistically significant annualized declines of 46% (95% confidence interval 2%–70%) and 49% (95% confidence interval 6%–72%) were observed in hospital admissions for acute myocardial infarction and other acute coronary heart disease diagnoses, respectively. There were no significant decreases in hospitalizations rates for respiratory diagnoses or seven other diagnostic groups evaluated. Conclusions Among Massachusetts Medicaid subscribers, use of a comprehensive tobacco cessation pharmacotherapy benefit was associated with a significant decrease in claims for hospitalizations for acute myocardial infarction and acute coronary heart disease, but no significant change in hospital claims for other diagnoses. For low-income smokers, removing the barriers to the use of smoking cessation pharmacotherapy has the potential to decrease short-term utilization of hospital services. Please see later in the article for the Editors' Summary PMID:21170313
Theoretical Benefits of Dynamic Collimation in Pencil Beam Scanning Proton Therapy for Brain Tumors: Dosimetric and Radiobiological Metrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moignier, Alexandra, E-mail: alexandra-moignier@uiowa.edu; Gelover, Edgar; Wang, Dongxu

Purpose: To quantify the dosimetric benefit of using a dynamic collimation system (DCS) for penumbra reduction during the treatment of brain tumors by pencil beam scanning proton therapy (PBS PT). Methods and Materials: Collimated and uncollimated brain treatment plans were created for 5 patients previously treated with PBS PT and retrospectively enrolled in an institutional review board–approved study. The in-house treatment planning system, RDX, was used to generate the plans because it is capable of modeling both collimated and uncollimated beamlets. The clinically delivered plans were reproduced with uncollimated plans in terms of target coverage and organ at risk (OAR) sparingmore » to ensure a clinically relevant starting point, and collimated plans were generated to improve the OAR sparing while maintaining target coverage. Physical and biological comparison metrics, such as dose distribution conformity, mean and maximum doses, normal tissue complication probability, and risk of secondary brain cancer, were used to evaluate the plans. Results: The DCS systematically improved the dose distribution conformity while preserving the target coverage. The average reduction of the mean dose to the 10-mm ring surrounding the target and the healthy brain were 13.7% (95% confidence interval [CI] 11.6%-15.7%; P<.0001) and 25.1% (95% CI 16.8%-33.4%; P<.001), respectively. This yielded an average reduction of 24.8% (95% CI 0.8%-48.8%; P<.05) for the brain necrosis normal tissue complication probability using the Flickinger model, and 25.1% (95% CI 16.8%-33.4%; P<.001) for the risk of secondary brain cancer. A general improvement of the OAR sparing was also observed. Conclusion: The lateral penumbra reduction afforded by the DCS increases the normal tissue sparing capabilities of PBS PT for brain cancer treatment while preserving target coverage.« less
ACTS Experiments Program

NASA Technical Reports Server (NTRS)

Schertler, R. J.

1986-01-01

An overview of the ACTS Experiments Program is presented. ACTS is being developed and will flight test the advanced technologies associated with: a Ka-band multibeam antenna, onboard signal processing and switching as well as laser communications. A nominal 3 yr experiments program is planned. Through the experiments program, the capabilities of the ACTS system will be made available to U.S. industry, university and government experimenters to test, prove the feasibility and evaluate the key ACTS system technologies. Communication modes of operation using the baseband processor and microwave switch matrix are presented, along with the antenna coverage pattern. Potential experiment categories are also presented and briefly discussed. An overall schedule of activities associated with the experiments program is outlined. Results of the ACTS Experiments Program will provide information vital to successful industry implementation of ACTS technology in a future operational system.
Comparing Methods of Assessing Dog Rabies Vaccination Coverage in Rural and Urban Communities in Tanzania

PubMed Central

Sambo, Maganga; Johnson, Paul C. D.; Hotopp, Karen; Changalucha, Joel; Cleaveland, Sarah; Kazwala, Rudovick; Lembo, Tiziana; Lugelo, Ahmed; Lushasi, Kennedy; Maziku, Mathew; Mbunda, Eberhard; Mtema, Zacharia; Sikana, Lwitiko; Townsend, Sunny E.; Hampson, Katie

2017-01-01

Rabies can be eliminated by achieving comprehensive coverage of 70% of domestic dogs during annual mass vaccination campaigns. Estimates of vaccination coverage are, therefore, required to evaluate and manage mass dog vaccination programs; however, there is no specific guidance for the most accurate and efficient methods for estimating coverage in different settings. Here, we compare post-vaccination transects, school-based surveys, and household surveys across 28 districts in southeast Tanzania and Pemba island covering rural, urban, coastal and inland settings, and a range of different livelihoods and religious backgrounds. These approaches were explored in detail in a single district in northwest Tanzania (Serengeti), where their performance was compared with a complete dog population census that also recorded dog vaccination status. Post-vaccination transects involved counting marked (vaccinated) and unmarked (unvaccinated) dogs immediately after campaigns in 2,155 villages (24,721 dogs counted). School-based surveys were administered to 8,587 primary school pupils each representing a unique household, in 119 randomly selected schools approximately 2 months after campaigns. Household surveys were conducted in 160 randomly selected villages (4,488 households) in July/August 2011. Costs to implement these coverage assessments were $12.01, $66.12, and $155.70 per village for post-vaccination transects, school-based, and household surveys, respectively. Simulations were performed to assess the effect of sampling on the precision of coverage estimation. The sampling effort required to obtain reasonably precise estimates of coverage from household surveys is generally very high and probably prohibitively expensive for routine monitoring across large areas, particularly in communities with high human to dog ratios. School-based surveys partially overcame sampling constraints, however, were also costly to obtain reasonably precise estimates of coverage. Post-vaccination transects provided precise and timely estimates of community-level coverage that could be used to troubleshoot the performance of campaigns across large areas. However, transects typically overestimated coverage by around 10%, which therefore needs consideration when evaluating the impacts of campaigns. We discuss the advantages and disadvantages of these different methods and make recommendations for how vaccination campaigns can be better monitored and managed at different stages of rabies control and elimination programs. PMID:28352630
Human resources for treating HIV/AIDS: needs, capacities, and gaps.

PubMed

Bärnighausen, Till; Bloom, David E; Humair, Salal

2007-11-01

Despite recent international efforts to scale-up antiretroviral treatment (ART), more than 5 million people needing ART in low- and middle-income countries (LMIC) do not receive it. Limited human resources to treat HIV/AIDS (HRHA) are one of the main constraints to achieving universal ART coverage. We model the gap between needed and available HRHA to quantify the challenge of achieving and sustaining universal ART coverage by 2017. We estimate the HRHA gap in LMIC using recently published estimates of ART coverage, HIV incidence, health-worker emigration rates, mortality rates of people needing ART, and numbers of HRHA needed to treat 1000 ART patients (based on review studies, 2006). We project the HRHA gap in 10 years (2017) using a simple discrete-time model with a health worker pool replenished through education and depleted through emigration/death; a population needing ART replenished with a given HIV incidence rate; and higher survival rates for treated populations. We analyze the effects of varying assumptions about HRHA inflows and outflows and the evolution of the HIV pandemic in three different regional base cases (sub-Saharan Africa, non-sub-Saharan African LMIC, and South Africa). Current ART coverage for LMIC is around 28%-32% and, other things equal, will drop to 16%-19% by 2017 with constant current HRHA production rates. A naive model, ignoring the increased survival probability resulting from ART, suggests that approximately the current number of HRHA in ART services needs to be added every year for the next ten years to achieve universal coverage by 2017. In a model accounting for increased survival of treated patients, outcomes vary by region; sub-Saharan Africa requires two times, non-sub-Saharan African LMIC require 1.5 times and South Africa requires more than three times their respective current HRHA population to be added every year for the next 10 years to achieve universal coverage by 2017. Even if achieved by 2017, sustaining universal coverage requires further HRHA increases until the system reaches steady state. ART coverage is sensitive to HRHA inflow and emigration. Our model quantifies the challenge of closing the HRHA gap in LMIC. It shows that strategies to achieve universal ART coverage must account for feedback due to higher survival probabilities of people receiving ART. It suggests that universal ART coverage is unlikely to be achieved and sustained with increased HRHA inflows alone, but will require decreased HRHA outflows, substantially reduced HIV incidence, or changes in the nature or organization of care. Means to decrease HRHA emigration outflows include scholarships for healthcare education that are conditional on the recipient delivering ART in a country with high ART need for a number of years, training health workers who are not internationally mobile, or changing recruitment policies in countries receiving health workers from the developing world. Effective organizational changes include those that reduce the number of HRHA required to treat a fixed number of patients. Given the large number of health workers that even optimistic assumptions suggest will be needed in ART services in the coming decades, policymakers must ensure that the flow of workers into ART programs does not jeopardize the provision of other important health services.
Knowledge as a predictor of insurance coverage under the Affordable Care Act

PubMed Central

Hoerl, Maximiliane; Wuppermann, Amelie; Barcellos, Silvia H.; Bauhoff, Sebastian; Winter, Joachim K.

2016-01-01

Background The Affordable Care Act established policy mechanisms to increase health insurance coverage in the United States. While insurance coverage has increased, 10 to 15% of the U.S. population remains uninsured. Objectives To assess whether health insurance literacy and financial literacy predict being uninsured, covered by Medicaid, or covered by Marketplace insurance, holding demographic characteristics, attitudes toward risk, and political affiliation constant. Research Design Analysis of longitudinal data from fall 2013 and spring 2015 including financial and health insurance literacy and key covariates collected in 2013. Subjects 2,742 U.S. residents ages 18-64, 525 uninsured in fall 2013, participating in the RAND American Life Panel, a nationally representative internet panel. Measures Self-reported health insurance status and type as of spring 2015. Results Among the uninsured in 2013, higher financial and health insurance literacy were associated with greater probability of being insured in 2015. For a typical uninsured individual in 2013, the probability of being insured in 2015 was 8.3 percentage points higher with high compared to low financial literacy, and 9.2 percentage points higher with high compared to low health insurance literacy. For the general population, those with high financial and health insurance literacy were more likely to obtain insurance via Medicaid or the Marketplaces compared to being uninsured. The magnitude of coefficients for these predictors was similar to that of commonly used demographic covariates. Conclusions A lack of understanding about health insurance concepts and financial illiteracy predict who remains uninsured. Outreach and consumer-education programs should consider these characteristics. PMID:27820594
The impact of race, income, drug abuse and dependence on health insurance coverage among US adults.

PubMed

Wang, Nianyang; Xie, Xin

2017-06-01

Little is known about the impact of drug abuse/dependence on health insurance coverage, especially by race groups and income levels. In this study, we examine the disparities in health insurance predictors and investigate the impact of drug use (alcohol abuse/dependence, nicotine dependence, and illicit drug abuse/dependence) on lack of insurance across different race and income groups. To perform the analysis, we used insurance data (8057 uninsured and 28,590 insured individual adults) from the National Surveys on Drug Use and Health (NSDUH 2011). To analyze the likelihood of being uninsured we performed weighted binomial logistic regression analyses. The results show that the overall prevalence of lacking insurance was 19.6 %. However, race differences in lack of insurance exist, especially for Hispanics who observe the highest probability of being uninsured (38.5 %). Furthermore, we observe that the lowest income level bracket (annual income <$20,000) is associated with the highest likelihood of being uninsured (37.3 %). As the result of this investigation, we observed the following relationship between drug use and lack of insurance: alcohol abuse/dependence and nicotine dependence tend to increase the risk of lack of insurance for African Americans and whites, respectively; illicit drug use increases such risk for whites; alcohol abuse/dependence increases the likelihood of lack of insurance for the group with incomes $20,000-$49,999, whereas nicotine dependence is associated with higher probability of lack of insurance for most income groups. These findings provide some useful insights for policy makers in making decisions regarding unmet health insurance coverage.
Probability of Future Observations Exceeding One-Sided, Normal, Upper Tolerance Limits

DOE PAGES

Edwards, Timothy S.

2014-10-29

Normal tolerance limits are frequently used in dynamic environments specifications of aerospace systems as a method to account for aleatory variability in the environments. Upper tolerance limits, when used in this way, are computed from records of the environment and used to enforce conservatism in the specification by describing upper extreme values the environment may take in the future. Components and systems are designed to withstand these extreme loads to ensure they do not fail under normal use conditions. The degree of conservatism in the upper tolerance limits is controlled by specifying the coverage and confidence level (usually written inmore » “coverage/confidence” form). Moreover, in high-consequence systems it is common to specify tolerance limits at 95% or 99% coverage and confidence at the 50% or 90% level. Despite the ubiquity of upper tolerance limits in the aerospace community, analysts and decision-makers frequently misinterpret their meaning. The misinterpretation extends into the standards that govern much of the acceptance and qualification of commercial and government aerospace systems. As a result, the risk of a future observation of the environment exceeding the upper tolerance limit is sometimes significantly underestimated by decision makers. This note explains the meaning of upper tolerance limits and a related measure, the upper prediction limit. So, the objective of this work is to clarify the probability of exceeding these limits in flight so that decision-makers can better understand the risk associated with exceeding design and test levels during flight and balance the cost of design and development with that of mission failure.« less
Modelling heterogeneity variances in multiple treatment comparison meta-analysis – Are informative priors the better solution?

PubMed Central

2013-01-01

Background Multiple treatment comparison (MTC) meta-analyses are commonly modeled in a Bayesian framework, and weakly informative priors are typically preferred to mirror familiar data driven frequentist approaches. Random-effects MTCs have commonly modeled heterogeneity under the assumption that the between-trial variance for all involved treatment comparisons are equal (i.e., the ‘common variance’ assumption). This approach ‘borrows strength’ for heterogeneity estimation across treatment comparisons, and thus, ads valuable precision when data is sparse. The homogeneous variance assumption, however, is unrealistic and can severely bias variance estimates. Consequently 95% credible intervals may not retain nominal coverage, and treatment rank probabilities may become distorted. Relaxing the homogeneous variance assumption may be equally problematic due to reduced precision. To regain good precision, moderately informative variance priors or additional mathematical assumptions may be necessary. Methods In this paper we describe four novel approaches to modeling heterogeneity variance - two novel model structures, and two approaches for use of moderately informative variance priors. We examine the relative performance of all approaches in two illustrative MTC data sets. We particularly compare between-study heterogeneity estimates and model fits, treatment effect estimates and 95% credible intervals, and treatment rank probabilities. Results In both data sets, use of moderately informative variance priors constructed from the pair wise meta-analysis data yielded the best model fit and narrower credible intervals. Imposing consistency equations on variance estimates, assuming variances to be exchangeable, or using empirically informed variance priors also yielded good model fits and narrow credible intervals. The homogeneous variance model yielded high precision at all times, but overall inadequate estimates of between-trial variances. Lastly, treatment rankings were similar among the novel approaches, but considerably different when compared with the homogenous variance approach. Conclusions MTC models using a homogenous variance structure appear to perform sub-optimally when between-trial variances vary between comparisons. Using informative variance priors, assuming exchangeability or imposing consistency between heterogeneity variances can all ensure sufficiently reliable and realistic heterogeneity estimation, and thus more reliable MTC inferences. All four approaches should be viable candidates for replacing or supplementing the conventional homogeneous variance MTC model, which is currently the most widely used in practice. PMID:23311298
Analytical Study on Multi-Tier 5G Heterogeneous Small Cell Networks: Coverage Performance and Energy Efficiency.

PubMed

Xiao, Zhu; Liu, Hongjing; Havyarimana, Vincent; Li, Tong; Wang, Dong

2016-11-04

In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells' deployment density. By taking the fairness and user experience into consideration, we propose a disjoint channel allocation scheme and derive the system channel throughput for various tiers. Further, we formulate the energy efficiency optimization problem for multi-tier HetNets in terms of throughput performance and resource allocation fairness. To solve this problem, we devise a linear programming based approach to obtain the available area of the feasible solutions. System-level simulations demonstrate that the small cells' deployment density has a significant effect on the coverage performance and energy efficiency. Simulation results also reveal that there exits an optimal small cell base station (SBS) density ratio between pico-tier and femto-tier which can be applied to maximize the energy efficiency and at the same time enhance the system performance. Our findings provide guidance for the design of multi-tier HetNets for improving the coverage performance as well as the energy efficiency.
Analytical Study on Multi-Tier 5G Heterogeneous Small Cell Networks: Coverage Performance and Energy Efficiency

PubMed Central

Xiao, Zhu; Liu, Hongjing; Havyarimana, Vincent; Li, Tong; Wang, Dong

2016-01-01

In this paper, we investigate the coverage performance and energy efficiency of multi-tier heterogeneous cellular networks (HetNets) which are composed of macrocells and different types of small cells, i.e., picocells and femtocells. By virtue of stochastic geometry tools, we model the multi-tier HetNets based on a Poisson point process (PPP) and analyze the Signal to Interference Ratio (SIR) via studying the cumulative interference from pico-tier and femto-tier. We then derive the analytical expressions of coverage probabilities in order to evaluate coverage performance in different tiers and investigate how it varies with the small cells’ deployment density. By taking the fairness and user experience into consideration, we propose a disjoint channel allocation scheme and derive the system channel throughput for various tiers. Further, we formulate the energy efficiency optimization problem for multi-tier HetNets in terms of throughput performance and resource allocation fairness. To solve this problem, we devise a linear programming based approach to obtain the available area of the feasible solutions. System-level simulations demonstrate that the small cells’ deployment density has a significant effect on the coverage performance and energy efficiency. Simulation results also reveal that there exits an optimal small cell base station (SBS) density ratio between pico-tier and femto-tier which can be applied to maximize the energy efficiency and at the same time enhance the system performance. Our findings provide guidance for the design of multi-tier HetNets for improving the coverage performance as well as the energy efficiency. PMID:27827917

Mapping the Distribution and Biomass of Emergent Aquatic Plants in the Sacramento-San Joaquin River Delta of California Using Landsat Imagery Analysis

NASA Technical Reports Server (NTRS)

Potter, Christopher

2015-01-01

This study evaluated the cost-effective and timely use of Landsat imagery to map and monitor emergent aquatic plant biomass and to filter satellite image products for the most probable locations of water hyacinth coverage in the Delta based on field observations collected immediately after satellite image acquisition.
Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

DOE PAGES

Perreault Levasseur, Laurence; Hezaveh, Yashar D.; Wechsler, Risa H.

2017-11-15

In Hezaveh et al. (2017) we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational lensing systems. Here we demonstrate a method for obtaining the uncertainties of these parameters. We review the framework of variational inference to obtain approximate posteriors of Bayesian neural networks and apply it to a network trained to estimate the parameters of the Singular Isothermal Ellipsoid plus external shear and total flux magnification. We show that the method can capture the uncertainties due to different levels of noise in the input data,more » as well as training and architecture-related errors made by the network. To evaluate the accuracy of the resulting uncertainties, we calculate the coverage probabilities of marginalized distributions for each lensing parameter. By tuning a single hyperparameter, the dropout rate, we obtain coverage probabilities approximately equal to the confidence levels for which they were calculated, resulting in accurate and precise uncertainty estimates. Our results suggest that neural networks can be a fast alternative to Monte Carlo Markov Chains for parameter uncertainty estimation in many practical applications, allowing more than seven orders of magnitude improvement in speed.« less
Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

NASA Astrophysics Data System (ADS)

Perreault Levasseur, Laurence; Hezaveh, Yashar D.; Wechsler, Risa H.

2017-11-01

In Hezaveh et al. we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational-lensing systems. Here we demonstrate a method for obtaining the uncertainties of these parameters. We review the framework of variational inference to obtain approximate posteriors of Bayesian neural networks and apply it to a network trained to estimate the parameters of the Singular Isothermal Ellipsoid plus external shear and total flux magnification. We show that the method can capture the uncertainties due to different levels of noise in the input data, as well as training and architecture-related errors made by the network. To evaluate the accuracy of the resulting uncertainties, we calculate the coverage probabilities of marginalized distributions for each lensing parameter. By tuning a single variational parameter, the dropout rate, we obtain coverage probabilities approximately equal to the confidence levels for which they were calculated, resulting in accurate and precise uncertainty estimates. Our results suggest that the application of approximate Bayesian neural networks to astrophysical modeling problems can be a fast alternative to Monte Carlo Markov Chains, allowing orders of magnitude improvement in speed.
Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perreault Levasseur, Laurence; Hezaveh, Yashar D.; Wechsler, Risa H.

In Hezaveh et al. (2017) we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational lensing systems. Here we demonstrate a method for obtaining the uncertainties of these parameters. We review the framework of variational inference to obtain approximate posteriors of Bayesian neural networks and apply it to a network trained to estimate the parameters of the Singular Isothermal Ellipsoid plus external shear and total flux magnification. We show that the method can capture the uncertainties due to different levels of noise in the input data,more » as well as training and architecture-related errors made by the network. To evaluate the accuracy of the resulting uncertainties, we calculate the coverage probabilities of marginalized distributions for each lensing parameter. By tuning a single hyperparameter, the dropout rate, we obtain coverage probabilities approximately equal to the confidence levels for which they were calculated, resulting in accurate and precise uncertainty estimates. Our results suggest that neural networks can be a fast alternative to Monte Carlo Markov Chains for parameter uncertainty estimation in many practical applications, allowing more than seven orders of magnitude improvement in speed.« less
Resolution Enhanced Magnetic Sensing System for Wide Coverage Real Time UXO Detection

NASA Astrophysics Data System (ADS)

Zalevsky, Zeev; Bregman, Yuri; Salomonski, Nizan; Zafrir, Hovav

2012-09-01

In this paper we present a new high resolution automatic detection algorithm based upon a Wavelet transform and then validate it in marine related experiments. The proposed approach allows obtaining an automatic detection in a very low signal to noise ratios. The amount of calculations is reduced, the magnetic trend is depressed and the probability of detection/ false alarm rate can easily be controlled. Moreover, the algorithm enables to distinguish between close targets. In the algorithm we use the physical dependence of the magnetic field of a magnetic dipole in order to define a Wavelet mother function that later on can detect magnetic targets modeled as dipoles and embedded in noisy surrounding, at improved resolution. The proposed algorithm was realized on synthesized targets and then validated in field experiments involving a marine surface-floating system for wide coverage real time unexploded ordinance (UXO) detection and mapping. The detection probability achieved in the marine experiment was above 90%. The horizontal radial error of most of the detected targets was only 16 m and two baseline targets that were immersed about 20 m one to another could easily be distinguished.
Clinical perspectives on medical marijuana (cannabis) for neurologic disorders

PubMed Central

Fife, Terry D.; Moawad, Heidi; Moschonas, Constantine; Hammond, Nancy

2015-01-01

Summary The American Academy of Neurology published an evidence-based systematic review of randomized controlled trials using marijuana (Cannabis sativa) or cannabinoids in neurologic disorders. Several cannabinoids showed effectiveness or probable effectiveness for spasticity, central pain, and painful spasms in multiple sclerosis. The review justifies insurance coverage for dronabinol and nabilone for these indications. Many insurance companies already cover these medications for other indications. It is unlikely that the review will alter coverage for herbal marijuana. Currently, no payers cover the costs of herbal medical marijuana because it is illegal under federal law and in most states. Cannabinoid preparations currently available by prescription may have a role in other neurologic conditions, but quality scientific evidence is lacking at this time. PMID:26336632
Clinical perspectives on medical marijuana (cannabis) for neurologic disorders.

PubMed

Fife, Terry D; Moawad, Heidi; Moschonas, Constantine; Shepard, Katie; Hammond, Nancy

2015-08-01

The American Academy of Neurology published an evidence-based systematic review of randomized controlled trials using marijuana ( Cannabis sativa ) or cannabinoids in neurologic disorders. Several cannabinoids showed effectiveness or probable effectiveness for spasticity, central pain, and painful spasms in multiple sclerosis. The review justifies insurance coverage for dronabinol and nabilone for these indications. Many insurance companies already cover these medications for other indications. It is unlikely that the review will alter coverage for herbal marijuana. Currently, no payers cover the costs of herbal medical marijuana because it is illegal under federal law and in most states. Cannabinoid preparations currently available by prescription may have a role in other neurologic conditions, but quality scientific evidence is lacking at this time.
Convective Weather Forecast Accuracy Analysis at Center and Sector Levels

NASA Technical Reports Server (NTRS)

Wang, Yao; Sridhar, Banavar

2010-01-01

This paper presents a detailed convective forecast accuracy analysis at center and sector levels. The study is aimed to provide more meaningful forecast verification measures to aviation community, as well as to obtain useful information leading to the improvements in the weather translation capacity models. In general, the vast majority of forecast verification efforts over past decades have been on the calculation of traditional standard verification measure scores over forecast and observation data analyses onto grids. These verification measures based on the binary classification have been applied in quality assurance of weather forecast products at the national level for many years. Our research focuses on the forecast at the center and sector levels. We calculate the standard forecast verification measure scores for en-route air traffic centers and sectors first, followed by conducting the forecast validation analysis and related verification measures for weather intensities and locations at centers and sectors levels. An approach to improve the prediction of sector weather coverage by multiple sector forecasts is then developed. The weather severe intensity assessment was carried out by using the correlations between forecast and actual weather observation airspace coverage. The weather forecast accuracy on horizontal location was assessed by examining the forecast errors. The improvement in prediction of weather coverage was determined by the correlation between actual sector weather coverage and prediction. observed and forecasted Convective Weather Avoidance Model (CWAM) data collected from June to September in 2007. CWAM zero-minute forecast data with aircraft avoidance probability of 60% and 80% are used as the actual weather observation. All forecast measurements are based on 30-minute, 60- minute, 90-minute, and 120-minute forecasts with the same avoidance probabilities. The forecast accuracy analysis for times under one-hour showed that the errors in intensity and location for center forecast are relatively low. For example, 1-hour forecast intensity and horizontal location errors for ZDC center were about 0.12 and 0.13. However, the correlation between sector 1-hour forecast and actual weather coverage was weak, for sector ZDC32, about 32% of the total variation of observation weather intensity was unexplained by forecast; the sector horizontal location error was about 0.10. The paper also introduces an approach to estimate the sector three-dimensional actual weather coverage by using multiple sector forecasts, which turned out to produce better predictions. Using Multiple Linear Regression (MLR) model for this approach, the correlations between actual observation and the multiple sector forecast model prediction improved by several percents at 95% confidence level in comparison with single sector forecast.
Determinants of apparent rural-urban differentials in measles vaccination uptake in Indonesia.

PubMed

Fernandez, Renae C; Awofeso, Niyi; Rammohan, Anu

2011-01-01

Regional differences in vaccination uptake are common in both developed and developing countries, and are often linked to the availability of healthcare services and socioeconomic factors. In 2007, 0.9 million eligible Indonesian children missed measles vaccination, and 19 456 cases of measles were documented among Indonesian children. The authors investigated rural-urban differentials in measles vaccination coverage among young Indonesian children, and sought to identify key factors influencing the probability of a child receiving the first dose of measles vaccination in Indonesia. Data used in the analyses were sourced from the nationally representative Indonesia Demographic and Health Survey 2007. The influence of location of residence, household wealth, maternal and paternal education, total children ever born and use of skilled birth attendants on measles vaccination coverage was investigated using bivariate analysis and chi-square tests. The independent effects of these variables were established using binomial logistic regression analysis. Indonesia's 2007 first-dose measles national vaccination coverage was, at 72.8%, lower than the 2008 global first-dose measles vaccination average coverage of 82%. Bivariate analysis revealed that the first-dose measles vaccination coverage in rural areas of Indonesia was 68.5%, compared with 80.1% in urban regions (p < 0.001). The apparent significance of rural residence in impairing vaccination coverage was marginal after controlling for the sex of the child, maternal age, maternal and paternal education, wealth, and access to skilled health workers. Apart from sustainable initiatives to increase measles vaccination coverage globally, it is important to close the rural-urban gap in Indonesia's measles vaccination uptake. Addressing critical determinants of inferior measles vaccination coverage in Indonesia's rural regions will facilitate major improvements in Indonesia's child health trends. This article suggests initiatives for addressing three of such determinants in Indonesia's rural areas: poverty, parental education and access to skilled health workers.
The impact of varicella vaccination on varicella-related hospitalization rates: global data review

PubMed Central

Hirose, Maki; Gilio, Alfredo Elias; Ferronato, Angela Esposito; Ragazzi, Selma Lopes Betta

2016-01-01

Abstract Objective: To describe the impact of varicella vaccination on varicella-related hospitalization rates in countries that implemented universal vaccination against the disease. Data source: We identified countries that implemented universal vaccination against varicella at the http://apps.who.int/immunization_monitoring/globalsummary/schedules site of the World Health Organization and selected articles in Pubmed describing the changes (pre/post-vaccination) in the varicella-related hospitalization rates in these countries, using the Keywords "varicella", "vaccination/vaccine" and "children" (or) "hospitalization". Publications in English published between January 1995 and May 2015 were included. Data synthesis: 24 countries with universal vaccination against varicella and 28 articles describing the impact of the vaccine on varicella-associated hospitalizations rates in seven countries were identified. The US had 81.4%–99.2% reduction in hospitalization rates in children younger than four years, 6–14 years after the onset of universal vaccination (1995), with vaccination coverage of 90%; Uruguay: 94% decrease (children aged 1–4 years) in six years, vaccination coverage of 90%; Canada: 93% decrease (age 1–4 years) in 10 years, coverage of 93%; Germany: 62.4% decrease (age 1–4 years) in 8 years, coverage of 78.2%; Australia: 76.8% decrease (age 1–4 years) in 5 years, coverage of 90%; Spain: 83.5% decrease (age <5 years) in four years, coverage of 77.2% and Italy 69.7%–73.8% decrease (general population), coverage of 60%–95%. Conclusions: The publications showed variations in the percentage of decrease in varicella-related hospitalization rates after universal vaccination in the assessed countries; the results probably depend on the time since the implementation of universal vaccination, differences in the studied age group, hospital admission criteria, vaccination coverage and strategy, which does not allow direct comparison between data. PMID:26965075
The impact of varicella vaccination on varicella-related hospitalization rates: global data review.

PubMed

Hirose, Maki; Gilio, Alfredo Elias; Ferronato, Angela Esposito; Ragazzi, Selma Lopes Betta

2016-09-01

to describe the impact of varicella vaccination on varicella-related hospitalization rates in countries that implemented universal vaccination against the disease. we identified countries that implemented universal vaccination against varicella at the http://apps.who.int/immunization_monitoring/globalsummary/schedules site of the World Health Organization and selected articles in Pubmed describing the changes (pre/post-vaccination) in the varicella-related hospitalization rates in these countries, using the Keywords "varicella", "vaccination/vaccine" and "children" (or) "hospitalization". Publications in English published between January 1995 and May 2015 were included. 24 countries with universal vaccination against varicella and 28 articles describing the impact of the vaccine on varicella-associated hospitalizations rates in seven countries were identified. The US had 81.4% -99.2% reduction in hospitalization rates in children younger than four years after 6-14 years after the onset of universal vaccination (1995), with vaccination coverage of 90%; Uruguay: 94% decrease (children aged 1-4 years) in six years, vaccination coverage of 90%; Canada: 93% decrease (age 1-4 years) in 10 years, coverage of 93%; Germany: 62.4% decrease (age 1-4 years) in 8 years, coverage of 78.2%; Australia: 76.8% decrease (age 1-4 years) in 5 years, coverage of 90%; Spain: 83.5% decrease (age <5 years) in four years, coverage of 77.2% and Italy 69.7% -73.8% decrease (general population), coverage of 60%-95%. The publications showed variations in the percentage of decrease in varicella-related hospitalization rates after universal vaccination in the assessed countries; the results probably depend on the time since the implementation of universal vaccination, differences in the studied age group, hospital admission criteria, vaccination coverage and strategy, which does not allow direct comparison between data. Copyright © 2016 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.
Trends of improved water and sanitation coverage around the globe between 1990 and 2010: inequality among countries and performance of official development assistance

PubMed Central

Cha, Seungman; Mankadi, Paul Mansiangi; Elhag, Mousab Siddig; Lee, Yongjoo; Jin, Yan

2017-01-01

ABSTRACT Background: As the Millennium Development Goals ended, and were replaced by the Sustainable Development Goals, efforts have been made to evaluate the achievements and performance of official development assistance (ODA) in the health sector. In this study, we explore trends in the expansion of water and sanitation coverage in developing countries and the performance of ODA. Design: We explored inequality across developing countries by income level, and investigated how ODA for water and sanitation was committed by country, region, and income level. Changes in inequality were tested via slope changes by investigating the interaction of year and income level with a likelihood ratio test. A random effects model was applied according to the results of the Hausman test. Results: The slope of the linear trend between economic level and sanitation coverage has declined over time. However, a random effects model suggested that the change in slope across years was not significant (e.g. for the slope change between 2000 and 2010: likelihood ratio χ2 = 2.49, probability > χ2 = 0.1146). A similar pro-rich pattern across developing countries and a non-significant change in the slope associated with different economic levels were demonstrated for water coverage. Our analysis shows that the inequality of water and sanitation coverage among countries across the world has not been addressed effectively during the past decade. Our findings demonstrate that the countries with the least coverage persistently received far less ODA per capita than did countries with much more extensive water and sanitation coverage, suggesting that ODA for water and sanitation is poorly targeted. Conclusion: The most deprived countries should receive more attention for water and sanitation improvements from the world health community. A strong political commitment to ODA targeting the countries with the least coverage is needed at the global level. PMID:28604256
Household Coverage with Adequately Iodized Salt Varies Greatly between Countries and by Residence Type and Socioeconomic Status within Countries: Results from 10 National Coverage Surveys123

PubMed Central

Knowles, Jacky M; Garrett, Greg S; Gorstein, Jonathan; Kupka, Roland; Situma, Ruth; Yadav, Kapil; Yusufali, Rizwan; Pandav, Chandrakant; Aaron, Grant J

2017-01-01

Background: Household coverage with iodized salt was assessed in 10 countries that implemented Universal Salt Iodization (USI). Objective: The objective of this paper was to summarize household coverage data for iodized salt, including the relation between coverage and residence type and socioeconomic status (SES). Methods: A review was conducted of results from cross-sectional multistage household cluster surveys with the use of stratified probability proportional to size design in Bangladesh, Ethiopia, Ghana, India, Indonesia, Niger, the Philippines, Senegal, Tanzania, and Uganda. Salt iodine content was assessed with quantitative methods in all cases. The primary indicator of coverage was percentage of households that used adequately iodized salt, with an additional indicator for salt with some added iodine. Indicators of risk were SES and residence type. We used 95% CIs to determine significant differences in coverage. Results: National household coverage of adequately iodized salt varied from 6.2% in Niger to 97.0% in Uganda. For salt with some added iodine, coverage varied from 52.4% in the Philippines to 99.5% in Uganda. Coverage with adequately iodized salt was significantly higher in urban than in rural households in Bangladesh (68.9% compared with 44.3%, respectively), India (86.4% compared with 69.8%, respectively), Indonesia (59.3% compared with 51.4%, respectively), the Philippines (31.5% compared with 20.2%, respectively), Senegal (53.3% compared with 19.0%, respectively), and Tanzania (89.2% compared with 57.6%, respectively). In 7 of 8 countries with data, household coverage of adequately iodized salt was significantly higher in high- than in low-SES households in Bangladesh (58.8% compared with 39.7%, respectively), Ghana (36.2% compared with 21.5%, respectively), India (80.6% compared with 70.5%, respectively), Indonesia (59.9% compared with 45.6%, respectively), the Philippines (39.4% compared with 17.3%, respectively), Senegal (50.7% compared with 27.6%, respectively) and Tanzania (80.9% compared with 51.3%, respectively). Conclusions: Uganda has achieved USI. In other countries, access to iodized salt is inequitable. Quality control and regulatory enforcement of salt iodization remain challenging. Notable progress toward USI has been made in Ethiopia and India. Assessing progress toward USI only through household salt does not account for potentially iodized salt consumed through processed foods. PMID:28404840
Household Coverage with Adequately Iodized Salt Varies Greatly between Countries and by Residence Type and Socioeconomic Status within Countries: Results from 10 National Coverage Surveys.

PubMed

Knowles, Jacky M; Garrett, Greg S; Gorstein, Jonathan; Kupka, Roland; Situma, Ruth; Yadav, Kapil; Yusufali, Rizwan; Pandav, Chandrakant; Aaron, Grant J

2017-05-01

Background: Household coverage with iodized salt was assessed in 10 countries that implemented Universal Salt Iodization (USI). Objective: The objective of this paper was to summarize household coverage data for iodized salt, including the relation between coverage and residence type and socioeconomic status (SES). Methods: A review was conducted of results from cross-sectional multistage household cluster surveys with the use of stratified probability proportional to size design in Bangladesh, Ethiopia, Ghana, India, Indonesia, Niger, the Philippines, Senegal, Tanzania, and Uganda. Salt iodine content was assessed with quantitative methods in all cases. The primary indicator of coverage was percentage of households that used adequately iodized salt, with an additional indicator for salt with some added iodine. Indicators of risk were SES and residence type. We used 95% CIs to determine significant differences in coverage. Results: National household coverage of adequately iodized salt varied from 6.2% in Niger to 97.0% in Uganda. For salt with some added iodine, coverage varied from 52.4% in the Philippines to 99.5% in Uganda. Coverage with adequately iodized salt was significantly higher in urban than in rural households in Bangladesh (68.9% compared with 44.3%, respectively), India (86.4% compared with 69.8%, respectively), Indonesia (59.3% compared with 51.4%, respectively), the Philippines (31.5% compared with 20.2%, respectively), Senegal (53.3% compared with 19.0%, respectively), and Tanzania (89.2% compared with 57.6%, respectively). In 7 of 8 countries with data, household coverage of adequately iodized salt was significantly higher in high- than in low-SES households in Bangladesh (58.8% compared with 39.7%, respectively), Ghana (36.2% compared with 21.5%, respectively), India (80.6% compared with 70.5%, respectively), Indonesia (59.9% compared with 45.6%, respectively), the Philippines (39.4% compared with 17.3%, respectively), Senegal (50.7% compared with 27.6%, respectively) and Tanzania (80.9% compared with 51.3%, respectively). Conclusions: Uganda has achieved USI. In other countries, access to iodized salt is inequitable. Quality control and regulatory enforcement of salt iodization remain challenging. Notable progress toward USI has been made in Ethiopia and India. Assessing progress toward USI only through household salt does not account for potentially iodized salt consumed through processed foods.
Infrared Multiphoton Dissociation of Peptide Cations in a Dual Pressure Linear Ion Trap Mass Spectrometer

PubMed Central

Gardner, Myles W.; Smith, Suncerae I.; Ledvina, Aaron R.; Madsen, James A.; Coon, Joshua J.; Schwartz, Jae C.; Stafford, George C.; Brodbelt, Jennifer S.

2009-01-01

A dual pressure linear ion trap mass spectrometer was modified to permit infrared multiphoton dissociation (IRMPD) in each of the two cells - the first a high pressure cell operated at nominally 5 × 10-3 Torr and the second a low pressure cell operated at nominally 3 × 10-4 Torr. When IRMPD was performed in the high pressure cell, most peptide ions did not undergo significant photodissociation; however, in the low pressure cell peptide cations were efficiently dissociated with less than 25 ms of IR irradiation regardless of charge state. IRMPD of peptide cations allowed the detection of low m/z product ions including the y1 fragments and immonium ions which are not typically observed by ion trap collision induced dissociation (CID). Photodissociation efficiencies of ~100% and MS/MS (tandem mass spectrometry) efficiencies of greater than 60% were observed for both multiply and singly protonated peptides. In general, higher sequence coverage of peptides was obtained using IRMPD over CID. Further, greater than 90% of the product ion current in the IRMPD mass spectra of doubly charged peptide ions was composed of singly charged product ions compared to the CID mass spectra in which the abundances of the multiply and singly charged product ions were equally divided. Highly charged primary product ions also underwent efficient photodissociation to yield singly charged secondary product ions, thus simplifying the IRMPD product ion mass spectra. PMID:19739654
Specifying the Probability Characteristics of Funnel Plot Control Limits: An Investigation of Three Approaches

PubMed Central

Manktelow, Bradley N.; Seaton, Sarah E.

2012-01-01

Background Emphasis is increasingly being placed on the monitoring and comparison of clinical outcomes between healthcare providers. Funnel plots have become a standard graphical methodology to identify outliers and comprise plotting an outcome summary statistic from each provider against a specified ‘target’ together with upper and lower control limits. With discrete probability distributions it is not possible to specify the exact probability that an observation from an ‘in-control’ provider will fall outside the control limits. However, general probability characteristics can be set and specified using interpolation methods. Guidelines recommend that providers falling outside such control limits should be investigated, potentially with significant consequences, so it is important that the properties of the limits are understood. Methods Control limits for funnel plots for the Standardised Mortality Ratio (SMR) based on the Poisson distribution were calculated using three proposed interpolation methods and the probability calculated of an ‘in-control’ provider falling outside of the limits. Examples using published data were shown to demonstrate the potential differences in the identification of outliers. Results The first interpolation method ensured that the probability of an observation of an ‘in control’ provider falling outside either limit was always less than a specified nominal probability (p). The second method resulted in such an observation falling outside either limit with a probability that could be either greater or less than p, depending on the expected number of events. The third method led to a probability that was always greater than, or equal to, p. Conclusion The use of different interpolation methods can lead to differences in the identification of outliers. This is particularly important when the expected number of events is small. We recommend that users of these methods be aware of the differences, and specify which interpolation method is to be used prior to any analysis. PMID:23029202
Global Estimates of Syphilis in Pregnancy and Associated Adverse Outcomes: Analysis of Multinational Antenatal Surveillance Data

PubMed Central

Newman, Lori; Kamb, Mary; Hawkes, Sarah; Gomez, Gabriela; Say, Lale; Seuc, Armando; Broutet, Nathalie

2013-01-01

Background The World Health Organization initiative to eliminate mother-to-child transmission of syphilis aims for ≥90% of pregnant women to be tested for syphilis and ≥90% to receive treatment by 2015. We calculated global and regional estimates of syphilis in pregnancy and associated adverse outcomes for 2008, as well as antenatal care (ANC) coverage for women with syphilis. Methods and Findings Estimates were based upon a health service delivery model. National syphilis seropositivity data from 97 of 193 countries and ANC coverage from 147 countries were obtained from World Health Organization databases. Proportions of adverse outcomes and effectiveness of screening and treatment were from published literature. Regional estimates of ANC syphilis testing and treatment were examined through sensitivity analysis. In 2008, approximately 1.36 million (range: 1.16 to 1.56 million) pregnant women globally were estimated to have probable active syphilis; of these, 80% had attended ANC. Globally, 520,905 (best case: 425,847; worst case: 615,963) adverse outcomes were estimated to be caused by maternal syphilis, including approximately 212,327 (174,938; 249,716) stillbirths (>28 wk) or early fetal deaths (22 to 28 wk), 91,764 (76,141; 107,397) neonatal deaths, 65,267 (56,929; 73,605) preterm or low birth weight infants, and 151,547 (117,848; 185,245) infected newborns. Approximately 66% of adverse outcomes occurred in ANC attendees who were not tested or were not treated for syphilis. In 2008, based on the middle case scenario, clinical services likely averted 26% of all adverse outcomes. Limitations include missing syphilis seropositivity data for many countries in Europe, the Mediterranean, and North America, and use of estimates for the proportion of syphilis that was “probable active,” and for testing and treatment coverage. Conclusions Syphilis continues to affect large numbers of pregnant women, causing substantial perinatal morbidity and mortality that could be prevented by early testing and treatment. In this analysis, most adverse outcomes occurred among women who attended ANC but were not tested or treated for syphilis, highlighting the need to improve the quality of ANC as well as ANC coverage. In addition, improved ANC data on syphilis testing coverage, positivity, and treatment are needed. Please see later in the article for the Editors' Summary PMID:23468598
Global estimates of syphilis in pregnancy and associated adverse outcomes: analysis of multinational antenatal surveillance data.

PubMed

Newman, Lori; Kamb, Mary; Hawkes, Sarah; Gomez, Gabriela; Say, Lale; Seuc, Armando; Broutet, Nathalie

2013-01-01

The World Health Organization initiative to eliminate mother-to-child transmission of syphilis aims for ≥ 90% of pregnant women to be tested for syphilis and ≥ 90% to receive treatment by 2015. We calculated global and regional estimates of syphilis in pregnancy and associated adverse outcomes for 2008, as well as antenatal care (ANC) coverage for women with syphilis. Estimates were based upon a health service delivery model. National syphilis seropositivity data from 97 of 193 countries and ANC coverage from 147 countries were obtained from World Health Organization databases. Proportions of adverse outcomes and effectiveness of screening and treatment were from published literature. Regional estimates of ANC syphilis testing and treatment were examined through sensitivity analysis. In 2008, approximately 1.36 million (range: 1.16 to 1.56 million) pregnant women globally were estimated to have probable active syphilis; of these, 80% had attended ANC. Globally, 520,905 (best case: 425,847; worst case: 615,963) adverse outcomes were estimated to be caused by maternal syphilis, including approximately 212,327 (174,938; 249,716) stillbirths (>28 wk) or early fetal deaths (22 to 28 wk), 91,764 (76,141; 107,397) neonatal deaths, 65,267 (56,929; 73,605) preterm or low birth weight infants, and 151,547 (117,848; 185,245) infected newborns. Approximately 66% of adverse outcomes occurred in ANC attendees who were not tested or were not treated for syphilis. In 2008, based on the middle case scenario, clinical services likely averted 26% of all adverse outcomes. Limitations include missing syphilis seropositivity data for many countries in Europe, the Mediterranean, and North America, and use of estimates for the proportion of syphilis that was "probable active," and for testing and treatment coverage. Syphilis continues to affect large numbers of pregnant women, causing substantial perinatal morbidity and mortality that could be prevented by early testing and treatment. In this analysis, most adverse outcomes occurred among women who attended ANC but were not tested or treated for syphilis, highlighting the need to improve the quality of ANC as well as ANC coverage. In addition, improved ANC data on syphilis testing coverage, positivity, and treatment are needed. Please see later in the article for the Editors' Summary.
Realistic respiratory motion margins for external beam partial breast irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conroy, Leigh; Quirk, Sarah; Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4

Purpose: Respiratory margins for partial breast irradiation (PBI) have been largely based on geometric observations, which may overestimate the margin required for dosimetric coverage. In this study, dosimetric population-based respiratory margins and margin formulas for external beam partial breast irradiation are determined. Methods: Volunteer respiratory data and anterior–posterior (AP) dose profiles from clinical treatment plans of 28 3D conformal radiotherapy (3DCRT) PBI patient plans were used to determine population-based respiratory margins. The peak-to-peak amplitudes (A) of realistic respiratory motion data from healthy volunteers were scaled from A = 1 to 10 mm to create respiratory motion probability density functions. Dosemore » profiles were convolved with the respiratory probability density functions to produce blurred dose profiles accounting for respiratory motion. The required margins were found by measuring the distance between the simulated treatment and original dose profiles at the 95% isodose level. Results: The symmetric dosimetric respiratory margins to cover 90%, 95%, and 100% of the simulated treatment population were 1.5, 2, and 4 mm, respectively. With patient set up at end exhale, the required margins were larger in the anterior direction than the posterior. For respiratory amplitudes less than 5 mm, the population-based margins can be expressed as a fraction of the extent of respiratory motion. The derived formulas in the anterior/posterior directions for 90%, 95%, and 100% simulated population coverage were 0.45A/0.25A, 0.50A/0.30A, and 0.70A/0.40A. The differences in formulas for different population coverage criteria demonstrate that respiratory trace shape and baseline drift characteristics affect individual respiratory margins even for the same average peak-to-peak amplitude. Conclusions: A methodology for determining population-based respiratory margins using real respiratory motion patterns and dose profiles in the AP direction was described. It was found that the currently used respiratory margin of 5 mm in partial breast irradiation may be overly conservative for many 3DCRT PBI patients. Amplitude alone was found to be insufficient to determine patient-specific margins: individual respiratory trace shape and baseline drift both contributed to the dosimetric target coverage. With respiratory coaching, individualized respiratory margins smaller than the full extent of motion could reduce planning target volumes while ensuring adequate coverage under respiratory motion.« less
Bayesian network meta-analysis of root coverage procedures: ranking efficacy and identification of best treatment.

PubMed

Buti, Jacopo; Baccini, Michela; Nieri, Michele; La Marca, Michele; Pini-Prato, Giovan P

2013-04-01

The aim of this work was to conduct a Bayesian network meta-analysis (NM) of randomized controlled trials (RCTs) to establish a ranking in efficacy and the best technique for coronally advanced flap (CAF)-based root coverage procedures. A literature search on PubMed, Cochrane libraries, EMBASE, and hand-searched journals until June 2012 was conducted to identify RCTs on treatments of Miller Class I and II gingival recessions with at least 6 months of follow-up. The treatment outcomes were recession reduction (RecRed), clinical attachment gain (CALgain), keratinized tissue gain (KTgain), and complete root coverage (CRC). Twenty-nine studies met the inclusion criteria, 20 of which were classified as at high risk of bias. The CAF+connective tissue graft (CTG) combination ranked highest in effectiveness for RecRed (Probability of being the best = 40%) and CALgain (Pr = 33%); CAF+enamel matrix derivative (EMD) was slightly better for CRC; CAF+Collagen Matrix (CM) appeared effective for KTgain (Pr = 69%). Network inconsistency was low for all outcomes excluding CALgain. CAF+CTG might be considered the gold standard in root coverage procedures. The low amount of inconsistency gives support to the reliability of the present findings. © 2012 John Wiley & Sons A/S.

Potential Standards and Methods for the National Guard’s Homeland Response Force

DTIC Science & Technology

2011-09-01

rapidly determine a missile launch and probable impact area ( Opall -Rome, 2009). Since 2006, Color Red coverage has expanded throughout the country...Manportable Air Defense (MANPAD) systems, land mines , advanced communication systems, mortars, unmanned air systems (UAS), frequency-hopping...Consequence Management Response Force (CCMRF). Internal document. Opall -Rome, B. (2009, January19). In Israel: Anti-sniper gear spots rockets
An Alternative to Cohen's Standardized Mean Difference Effect Size: A Robust Parameter and Confidence Interval in the Two Independent Groups Case

ERIC Educational Resources Information Center

Algina, James; Keselman, H. J.; Penfield, Randall D.

2005-01-01

The authors argue that a robust version of Cohen's effect size constructed by replacing population means with 20% trimmed means and the population standard deviation with the square root of a 20% Winsorized variance is a better measure of population separation than is Cohen's effect size. The authors investigated coverage probability for…
Superficial Deposits at Gusev Crater Along Spirit Rover Traverses

NASA Technical Reports Server (NTRS)

Grant, J. A.; Arvidson, R.; Bell, J. F., III; Cabrol, N. A.; Carr, M. H.; Christensen, P.; Crumpler, L.; DesMarsais, D.; Ehlmann, B. L.; Ming, Douglas W.

2004-01-01

The Mars Exploration Rover Spirit has traversed a fairly flat, rock-strewn terrain whose surface is shaped primarily by impact events, although some of the landscape has been altered by eolian processes.Impacts ejected basaltic rocks that probably were part of locally formed lava flows from at least 10 meters depth.Some rocks have been textured and/or partially buried by windblown sediments less than 2 millimeters in diameter that concentrate within shallow, partially filled, circular impact depressions referred to as hollows.The terrain traversed during the 90-sol (martian solar day) nominal mission shows no evidence for an ancient lake in Gusev crater.
Comparison of the radiological and chemical toxicity of lead

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beitel, G.A.; Mott, S.

1995-03-01

This report estimates the worst-case radiological dose to an individual from ingested lead containing picocurie levels of radionuclides and then compares the calculated radiological health effects to the chemical toxic effects from that same lead. This comparison provides an estimate of the consequences of inadvertently recycling, in the commercial market, lead containing nominally undetectable concentrations of radionuclides. Quantitative expressions for the radiological and chemical toxicities of lead are based on concentrations of lead in the blood stream. The result shows that the chemical toxicity of lead is a greater health hazard, by orders of magnitude, than any probable companion radiationmore » dose.« less
Surficial deposits at Gusev crater along Spirit Rover traverses

USGS Publications Warehouse

Grant, J. A.; Arvidson, R.; Bell, J.F.; Cabrol, N.A.; Carr, M.H.; Christensen, P.; Crumpler, L.; Des Marais, D.J.; Ehlmann, B.L.; Farmer, J.; Golombek, M.; Grant, F.D.; Greeley, R.; Herkenhoff, K.; Li, R.; McSween, H.Y.; Ming, D. W.; Moersch, J.; Rice, J. W.; Ruff, S.; Richter, L.; Squyres, S.; Sullivan, R.; Weitz, C.

2004-01-01

The Mars Exploration Rover Spirit has traversed a fairly flat, rock-strewn terrain whose surface is shaped primarily by impact events, although some of the landscape has been altered by eolian processes. Impacts ejected basaltic rocks that probably were part of locally formed lava flows from at least 10 meters depth. Some rocks have been textured and/or partially buried by windblown sediments less than 2 millimeters in diameter that concentrate within shallow, partially filled, circular impact depressions referred to as hollows. The terrain traversed during the 90-sol (martian solar day) nominal mission shows no evidence for an ancient lake in Gusev crater.
Surveillance and Datalink Communication Performance Analysis for Distributed Separation Assurance System Architectures

NASA Technical Reports Server (NTRS)

Chung, William W.; Linse, Dennis J.; Alaverdi, Omeed; Ifarraguerri, Carlos; Seifert, Scott C.; Salvano, Dan; Calender, Dale

2012-01-01

This study investigates the effects of two technical enablers: Automatic Dependent Surveillance - Broadcast (ADS-B) and digital datalink communication, of the Federal Aviation Administration s Next Generation Air Transportation System (NextGen) under two separation assurance (SA) system architectures: ground-based SA and airborne SA, on overall separation assurance performance. Datalink performance such as successful reception probability in both surveillance and communication messages, and surveillance accuracy are examined in various operational conditions. Required SA performance is evaluated as a function of subsystem performance, using availability, continuity, and integrity metrics to establish overall required separation assurance performance, under normal and off-nominal conditions.
Mariner Mars 1971 television picture catalog. Volume 2: Sequence design and picture coverage

NASA Technical Reports Server (NTRS)

Koskela, P. E.; Helton, M. R.; Seeley, L. N.; Zawacki, S. J.

1972-01-01

A collection of data relating to the Mariner 9 TV picture is presented. The data are arranged to offer speedy identification of what took place during entire science cycles, on individual revolutions, and during individual science links or sequences. Summary tables present the nominal design for each of the major picture-taking cycles, along with the sequences actually taken on each revolution. These tables permit identification at a glance, all TV sequences and the corresponding individual pictures for the first 262 revolutions (primary mission). A list of TV pictures, categorized according to their latitude and longitude, is also provided. Orthographic and/or mercator plots for all pictures, along with pertinent numerical data for their center points are presented. Other tables and plots of interest are also included. This document is based upon data contained in the Supplementary Experiment Data Record (SEDR) files as of 21 August 1972.
The shell game: a panoramic view of Fornax

NASA Astrophysics Data System (ADS)

Bate, N. F.; McMonigal, B.; Lewis, G. F.; Irwin, M. J.; Gonzalez-Solares, E.; Shanks, T.; Metcalfe, N.

2015-10-01

We present a panoramic study of the Fornax dwarf spheroidal galaxy, using data obtained as part of the VLT Survey Telescope (VST) ATLAS Survey. The data presented here - a subset of the full survey - uniformly cover a region of 25 deg2 centred on the galaxy, in g, r and i bands. This large area coverage reveals two key differences to previous studies of Fornax. First, data extending beyond the nominal tidal radius of the dwarf highlight the presence of a second distinct red giant branch population. This bluer red giant branch appears to be co-eval with the horizontal branch population. Secondly, a shell structure located approximately 1.4° from the centre of Fornax is shown to be a mis-identified background overdensity of galaxies. This last result casts further doubt on the hypothesis that Fornax underwent a gas-rich merger in its relatively recent past.
High Resolution Doppler Imager FY 2001,2002,2003 Operations and Algorithm Maintenance

NASA Technical Reports Server (NTRS)

Skinner, Wilbert

2004-01-01

During the performance period of this grant HRDI (High Resolution Doppler Imager) operations remained nominal. The instrument has suffered no loss of scientific capability and operates whenever sufficient power is available. Generally, there are approximately 5-7 days per month when the power level is too low to permit observations. The daily latitude coverage for HRDI measurements in the mesosphere, lower thermosphere (MLT) region are shown.It shows that during the time of this grant, HRDI operations collected data at a rate comparable to that achieved during the UARS (Upper Atmosphere Research Satellite) prime mission (1991 -1995). Data collection emphasized MLT wind to support the validation efforts of the TIDI instrument on TIMED, therefore fulfilling one of the primary objectives of this phase of the UARS mission. Skinner et al., (2003) present a summary of the instrument performance during this period.
Room temperature ferroelectricity in continuous croconic acid thin films

NASA Astrophysics Data System (ADS)

Jiang, Xuanyuan; Lu, Haidong; Yin, Yuewei; Zhang, Xiaozhe; Wang, Xiao; Yu, Le; Ahmadi, Zahra; Costa, Paulo S.; DiChiara, Anthony D.; Cheng, Xuemei; Gruverman, Alexei; Enders, Axel; Xu, Xiaoshan

2016-09-01

Ferroelectricity at room temperature has been demonstrated in nanometer-thin quasi 2D croconic acid thin films, by the polarization hysteresis loop measurements in macroscopic capacitor geometry, along with observation and manipulation of the nanoscale domain structure by piezoresponse force microscopy. The fabrication of continuous thin films of the hydrogen-bonded croconic acid was achieved by the suppression of the thermal decomposition using low evaporation temperatures in high vacuum, combined with growth conditions far from thermal equilibrium. For nominal coverages ≥20 nm, quasi 2D and polycrystalline films, with an average grain size of 50-100 nm and 3.5 nm roughness, can be obtained. Spontaneous ferroelectric domain structures of the thin films have been observed and appear to correlate with the grain patterns. The application of this solvent-free growth protocol may be a key to the development of flexible organic ferroelectric thin films for electronic applications.
How did the fracking controversy emerge in the period 2010-2012?

PubMed

Mazur, Allan

2016-02-01

In 2010-2012, the controversy over fracking grew rapidly, first in the United States, and then internationally. An important step was the anti-fracking documentary film Gasland. With help from celebrity sources, the film was produced and won a prize at the Sundance Film Festival by early 2010 and had an Oscar nomination by early 2011, in the meantime popularizing potent images of hazard including tainted aquifers and ignitable water running from kitchen faucets. During this period, major US news organizations paid little attention to the issue. The offshore Deepwater Horizon disaster of April 2010 spurred The New York Times to prolific reporting on potential risks of the new onshore technique for extracting shale gas. With flagship news coverage, the controversy had by 2012 gained wide media attention that evoked public concern and opposition, spreading from the United States to other nations. © The Author(s) 2014.
Model selection bias and Freedman's paradox

USGS Publications Warehouse

Lukacs, P.M.; Burnham, K.P.; Anderson, D.R.

2010-01-01

In situations where limited knowledge of a system exists and the ratio of data points to variables is small, variable selection methods can often be misleading. Freedman (Am Stat 37:152-155, 1983) demonstrated how common it is to select completely unrelated variables as highly "significant" when the number of data points is similar in magnitude to the number of variables. A new type of model averaging estimator based on model selection with Akaike's AIC is used with linear regression to investigate the problems of likely inclusion of spurious effects and model selection bias, the bias introduced while using the data to select a single seemingly "best" model from a (often large) set of models employing many predictor variables. The new model averaging estimator helps reduce these problems and provides confidence interval coverage at the nominal level while traditional stepwise selection has poor inferential properties. ?? The Institute of Statistical Mathematics, Tokyo 2009.
Room temperature ferroelectricity in continuous croconic acid thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Xuanyuan; Lu, Haidong; Yin, Yuewei

2016-09-05

Ferroelectricity at room temperature has been demonstrated in nanometer-thin quasi 2D croconic acid thin films, by the polarization hysteresis loop measurements in macroscopic capacitor geometry, along with observation and manipulation of the nanoscale domain structure by piezoresponse force microscopy. The fabrication of continuous thin films of the hydrogen-bonded croconic acid was achieved by the suppression of the thermal decomposition using low evaporation temperatures in high vacuum, combined with growth conditions far from thermal equilibrium. For nominal coverages ≥20 nm, quasi 2D and polycrystalline films, with an average grain size of 50–100 nm and 3.5 nm roughness, can be obtained. Spontaneous ferroelectric domain structuresmore » of the thin films have been observed and appear to correlate with the grain patterns. The application of this solvent-free growth protocol may be a key to the development of flexible organic ferroelectric thin films for electronic applications.« less
Brief Report: Investigating Uncertainty in the Minimum Mortality Temperature: Methods and Application to 52 Spanish Cities.

PubMed

Tobías, Aurelio; Armstrong, Ben; Gasparrini, Antonio

2017-01-01

The minimum mortality temperature from J- or U-shaped curves varies across cities with different climates. This variation conveys information on adaptation, but ability to characterize is limited by the absence of a method to describe uncertainty in estimated minimum mortality temperatures. We propose an approximate parametric bootstrap estimator of confidence interval (CI) and standard error (SE) for the minimum mortality temperature from a temperature-mortality shape estimated by splines. The coverage of the estimated CIs was close to nominal value (95%) in the datasets simulated, although SEs were slightly high. Applying the method to 52 Spanish provincial capital cities showed larger minimum mortality temperatures in hotter cities, rising almost exactly at the same rate as annual mean temperature. The method proposed for computing CIs and SEs for minimums from spline curves allows comparing minimum mortality temperatures in different cities and investigating their associations with climate properly, allowing for estimation uncertainty.
Strain sensors optimal placement for vibration-based structural health monitoring. The effect of damage on the initially optimal configuration

NASA Astrophysics Data System (ADS)

Loutas, T. H.; Bourikas, A.

2017-12-01

We revisit the optimal sensor placement of engineering structures problem with an emphasis on in-plane dynamic strain measurements and to the direction of modal identification as well as vibration-based damage detection for structural health monitoring purposes. The approach utilized is based on the maximization of a norm of the Fisher Information Matrix built with numerically obtained mode shapes of the structure and at the same time prohibit the sensorization of neighbor degrees of freedom as well as those carrying similar information, in order to obtain a satisfactory coverage. A new convergence criterion of the Fisher Information Matrix (FIM) norm is proposed in order to deal with the issue of choosing an appropriate sensor redundancy threshold, a concept recently introduced but not further investigated concerning its choice. The sensor configurations obtained via a forward sequential placement algorithm are sub-optimal in terms of FIM norm values but the selected sensors are not allowed to be placed in neighbor degrees of freedom providing thus a better coverage of the structure and a subsequent better identification of the experimental mode shapes. The issue of how service induced damage affects the initially nominated as optimal sensor configuration is also investigated and reported. The numerical model of a composite sandwich panel serves as a representative aerospace structure upon which our investigations are based.
Data Mining of Historical Human Data to Assess the Risk of Injury due to Dynamic Loads

NASA Technical Reports Server (NTRS)

Wells, Jesica; Somers, Jeffrey T.; Newby, N.; Gernhardt, Michael

2014-01-01

The NASA Occupant Protection Group is charged with ensuring crewmembers are protected during all dynamic phases of spaceflight. Previous work with outside experts has led to the development of a definition of acceptable risk (DAR) for space capsule vehicles. The DAR defines allowable probability rates for various categories of injuries. An important question is how to validate these probabilities for a given vehicle. One approach is to impact test human volunteers under projected nominal landing loads. The main drawback is the large number of subject tests required to attain a reasonable level of confidence that the injury probability rates would meet those outlined in the DAR. An alternative is to mine existing databases containing human responses to impact. Testing an anthropomorphic test device (ATD) at the same human-exposure levels could yield a range of ATD responses that would meet DAR. As one aspect of future vehicle validation, the ATD could be tested in the vehicle's seat and suit configuration at nominal landing loads and compared with the ATD responses supported by the human data set. This approach could reduce the number of human-volunteer tests NASA would need to conduct to validate that a vehicle meets occupant protection standards. METHODS: The U.S. Air Force has recorded hundreds of human responses to frontal, lateral, and spinal impacts at many acceleration levels and pulse durations. All of this data are stored on the Collaborative Biomechanics Data Network (CBDN), which is maintained by the Wright Patterson Air Force Base (WPAFB). The test device for human occupant restraint (THOR) ATD was impact tested on WPAFB's horizontal impulse accelerator (HIA) matching human-volunteer exposures on the HIA to 5 frontal and 3 spinal loading conditions. No human injuries occurred as a result of these impact conditions. Peak THOR response variables for neck axial tension and compression, and thoracic-spine axial compression were collected. Maximal chest deflection was determined from motion capture video of the impact test. HIC- 15 and BRIC were calculated from head acceleration responses. Given the number of human subjects for each test condition a confidence interval of injury probability will be obtained. RESULTS: Results will be discussed in terms of injury-risk probability estimates based on the human data set evaluated. Also, gaps in the data set will be identified. These gaps could be one of two types. One is areas where additional THOR testing would increase the comparable human data set, thereby improving confidence in the injury probability rate. The other is where additional human testing would assist in obtaining information on other acceleration levels or directions. DISCUSSION: The historical human data showed validity of the THOR ATD for supplemental testing. The historical human data are limited in scope, however. Further data are needed to characterize the effects of sex, age, anthropometry, and deconditioning due to spaceflight on risk of injury
A Distributed and Energy-Efficient Algorithm for Event K-Coverage in Underwater Sensor Networks

PubMed Central

Jiang, Peng; Xu, Yiming; Liu, Jun

2017-01-01

For event dynamic K-coverage algorithms, each management node selects its assistant node by using a greedy algorithm without considering the residual energy and situations in which a node is selected by several events. This approach affects network energy consumption and balance. Therefore, this study proposes a distributed and energy-efficient event K-coverage algorithm (DEEKA). After the network achieves 1-coverage, the nodes that detect the same event compete for the event management node with the number of candidate nodes and the average residual energy, as well as the distance to the event. Second, each management node estimates the probability of its neighbor nodes’ being selected by the event it manages with the distance level, the residual energy level, and the number of dynamic coverage event of these nodes. Third, each management node establishes an optimization model that uses expectation energy consumption and the residual energy variance of its neighbor nodes and detects the performance of the events it manages as targets. Finally, each management node uses a constrained non-dominated sorting genetic algorithm (NSGA-II) to obtain the Pareto set of the model and the best strategy via technique for order preference by similarity to an ideal solution (TOPSIS). The algorithm first considers the effect of harsh underwater environments on information collection and transmission. It also considers the residual energy of a node and a situation in which the node is selected by several other events. Simulation results show that, unlike the on-demand variable sensing K-coverage algorithm, DEEKA balances and reduces network energy consumption, thereby prolonging the network’s best service quality and lifetime. PMID:28106837
Sci—Thur PM: Planning and Delivery — 04: Respiratory margin derivation and verification in partial breast irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quirk, S; Conroy, L; Smith, WL

Partial breast irradiation (PBI) following breast-conserving surgery is emerging as an effective means to achieve local control and reduce irradiated breast volume. Patients are planned on a static CT image; however, treatment is delivered while the patient is free-breathing. Respiratory motion can degrade plan quality by reducing target coverage and/or dose homogeneity. A variety of methods can be used to determine the required margin for respiratory motion in PBI. We derive geometric and dosimetric respiratory 1D margin. We also verify the adequacy of the typical 5 mm respiratory margin in 3D by evaluating plan quality for increasing respiratory amplitudes (2–20more » mm). Ten PBI plans were used for dosimetric evaluation. A database of volunteer respiratory data, with similar characteristics to breast cancer patients, was used for this study. We derived a geometric 95%-margin of 3 mm from the population respiratory data. We derived a dosimetric 95%-margin of 2 mm by convolving 1D dose profiles with respiratory probability density functions. The 5 mm respiratory margin is possibly too large when 1D coverage is assessed and could lead to unnecessary normal tissue irradiation. Assessing margins only for coverage may be insufficient; 3D dosimetric assessment revealed degradation in dose homogeneity is the limiting factor, not target coverage. Hotspots increased even for the smallest respiratory amplitudes, while target coverage only degraded at amplitudes greater than 10 mm. The 5 mm respiratory margin is adequate for coverage, but due to plan quality degradation, respiratory management is recommended for patients with respiratory amplitudes greater than 10 mm.« less
A Distributed and Energy-Efficient Algorithm for Event K-Coverage in Underwater Sensor Networks.

PubMed

Jiang, Peng; Xu, Yiming; Liu, Jun

2017-01-19

For event dynamic K-coverage algorithms, each management node selects its assistant node by using a greedy algorithm without considering the residual energy and situations in which a node is selected by several events. This approach affects network energy consumption and balance. Therefore, this study proposes a distributed and energy-efficient event K-coverage algorithm (DEEKA). After the network achieves 1-coverage, the nodes that detect the same event compete for the event management node with the number of candidate nodes and the average residual energy, as well as the distance to the event. Second, each management node estimates the probability of its neighbor nodes' being selected by the event it manages with the distance level, the residual energy level, and the number of dynamic coverage event of these nodes. Third, each management node establishes an optimization model that uses expectation energy consumption and the residual energy variance of its neighbor nodes and detects the performance of the events it manages as targets. Finally, each management node uses a constrained non-dominated sorting genetic algorithm (NSGA-II) to obtain the Pareto set of the model and the best strategy via technique for order preference by similarity to an ideal solution (TOPSIS). The algorithm first considers the effect of harsh underwater environments on information collection and transmission. It also considers the residual energy of a node and a situation in which the node is selected by several other events. Simulation results show that, unlike the on-demand variable sensing K-coverage algorithm, DEEKA balances and reduces network energy consumption, thereby prolonging the network's best service quality and lifetime.
Activated adsorption of methane on clean and oxygen-modified Pt?111? and Pd?110?

NASA Astrophysics Data System (ADS)

Valden, M.; Pere, J.; Hirsimäki, M.; Suhonen, S.; Pessa, M.

1997-04-01

Activated adsorption of CH 4 on clean and oxygen modified Pt{111} and Pd{110} has been studied using molecular beam surface scattering. The absolute dissociation probability of CH 4 was measured as a function of the incident normal energy ( E) and the surface temperature ( Ts). The results from clean Pt{111} and Pd{110} are consistent with a direct dissociation mechanism. The dissociative chemisorption dynamics of CH 4 is addressed by using quantum mechanical and statistical models. The influence of adsorbed oxygen on the dissociative adsorption of CH 4 on both Pt{111} and Pd{110} shows that the dissociation probability decreases linearly with increasing oxygen coverage.

Recent Changes in Health Insurance Coverage for Urban and Rural Veterans: Evidence from the First Year of the Affordable Care Act.

PubMed

Boudreaux, Michel; Barath, Deanna; Blewett, Lynn A

2018-04-25

Prior to the Affordable Care Act, as many as 1.3 million veterans lacked health insurance. With the passage of the Affordable Care Act, veterans now have new pathways to coverage through Medicaid expansion in those states that chose to expand Medicaid and through private coverage options offered through the Health Insurance Marketplace. We examined the impact of the ACA on health insurance coverage for veterans in expansion and non-expansion states and for urban and rural veterans. We examined changes in veterans' health insurance coverage following the first year of the ACA, focusing on whether they lived in an urban or rural area and whether they live in a Medicaid expansion state. We used data on approximately 200,000 non-elderly community-dwelling veterans, obtained from the 2013-2014 American Community Survey and estimated differences in the adjusted probability of being uninsured between 2013 and 2014 for both urban and rural areas. Adjusted probabilities were computed by fitting logistic regressions controlling for age, gender, race, marital status, poverty status, education, and employment. There were an estimated 10.1 million U.S. non-elderly veterans in 2013; 82% lived in predominantly urban areas (8.3 million), and the remaining 18% (1.8 million) lived in predominately rural areas. Most veterans lived in the South (43.6%), and rural veterans were more likely to be Southerners than their urban counterparts. On every marker of economic well-being, rural veterans fared worse than urban veterans. They had a statistically significant higher chance of having incomes below 138% of FPG (20.0% versus 17.0%), of being out of the labor force (29.1% versus 23.0%), and of having no more than a high school education (39.6% versus 28.8%). Rural veterans were also more likely to experience at least one functional limitation. Overall, veterans in Medicaid expansion states experienced a significantly larger increase in insurance compared to veterans living in non-expansion states. For rural veterans in Medicaid expansion states, the increase in insurance was 3.5 percentage points, compared with 1.2 percentage points in non-expansion states. Our analysis found a substantial 24% relative decline in the rate of uninsurance for U.S. Veterans, from 9.3 to 7.1% between 2013 and 2014. We found that coverage gains in rural areas were due to gains in Medicaid and individual market coverage. Residence in a Medicaid expansion state was particularly influential for rural veterans - the increase in the insured rate was three times larger in Medicaid expansion states versus non-expansion states. The ACA has had a positive and significant impact on the ability of U.S. Veterans to obtain health insurance coverage specifically for low-income veterans living in rural areas. The poverty rate among Veterans is rising and is particularly an issue for the more recent Gulf War veterans. Providing affordable and accessible health insurance options is part of our commitment to those who have served our country. Our analysis also presents yet another reason for the 17 non-expansion states to consider a Medicaid expansion.
Public and private health insurance premiums: how do they affect the health insurance status of low-income childless adults?

PubMed

Guy, Gery P; Adams, E Kathleen; Atherly, Adam

2012-01-01

The Patient Protection and Affordable Care Act (ACA) will substantially increase public health insurance eligibility and alter the costs of insurance coverage. Using Current Population Survey (CPS) data from the period 2000-2008, we examine the effects of public and private health insurance premiums on the insurance status of low-income childless adults, a population substantially affected by the ACA. Results show higher public premiums to be associated with a decrease in the probability of having public insurance and an increase in the probability of being uninsured, while increased private premiums decrease the probability of having private insurance. Eligibility for premium assistance programs and increased subsidy levels are associated with lower rates of uninsurance. The magnitudes of the effects are quite modest and provide important implications for insurance expansions for childless adults under the ACA.
A quantum probability perspective on borderline vagueness.

PubMed

Blutner, Reinhard; Pothos, Emmanuel M; Bruza, Peter

2013-10-01

The term "vagueness" describes a property of natural concepts, which normally have fuzzy boundaries, admit borderline cases, and are susceptible to Zeno's sorites paradox. We will discuss the psychology of vagueness, especially experiments investigating the judgment of borderline cases and contradictions. In the theoretical part, we will propose a probabilistic model that describes the quantitative characteristics of the experimental finding and extends Alxatib's and Pelletier's () theoretical analysis. The model is based on a Hopfield network for predicting truth values. Powerful as this classical perspective is, we show that it falls short of providing an adequate coverage of the relevant empirical results. In the final part, we will argue that a substantial modification of the analysis put forward by Alxatib and Pelletier and its probabilistic pendant is needed. The proposed modification replaces the standard notion of probabilities by quantum probabilities. The crucial phenomenon of borderline contradictions can be explained then as a quantum interference phenomenon. © 2013 Cognitive Science Society, Inc.
Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way.

PubMed

Grimaldi, Claudio

2017-04-12

The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor than a futile attempt. Here we insist that even if extraterrestrial civilizations do exist and communicate, the likelihood of detecting their signals crucially depends on whether the Earth lies within a region of the galaxy covered by such signals. By considering possible populations of independent emitters in the galaxy, we build a statistical model of the domain covered by hypothetical extraterrestrial signals to derive the detection probability that the Earth is within such a domain. We show that for general distributions of the signal longevity and directionality, the mean number of detectable emitters is less than one even for detection probabilities as large as 50%, regardless of the number of emitters in the galaxy.
Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

NASA Astrophysics Data System (ADS)

Grimaldi, Claudio

2017-04-01

The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor than a futile attempt. Here we insist that even if extraterrestrial civilizations do exist and communicate, the likelihood of detecting their signals crucially depends on whether the Earth lies within a region of the galaxy covered by such signals. By considering possible populations of independent emitters in the galaxy, we build a statistical model of the domain covered by hypothetical extraterrestrial signals to derive the detection probability that the Earth is within such a domain. We show that for general distributions of the signal longevity and directionality, the mean number of detectable emitters is less than one even for detection probabilities as large as 50%, regardless of the number of emitters in the galaxy.
Empirical assessment of published effect sizes and power in the recent cognitive neuroscience and psychology literature.

PubMed

Szucs, Denes; Ioannidis, John P A

2017-03-01

We have empirically assessed the distribution of published effect sizes and estimated power by analyzing 26,841 statistical records from 3,801 cognitive neuroscience and psychology papers published recently. The reported median effect size was D = 0.93 (interquartile range: 0.64-1.46) for nominally statistically significant results and D = 0.24 (0.11-0.42) for nonsignificant results. Median power to detect small, medium, and large effects was 0.12, 0.44, and 0.73, reflecting no improvement through the past half-century. This is so because sample sizes have remained small. Assuming similar true effect sizes in both disciplines, power was lower in cognitive neuroscience than in psychology. Journal impact factors negatively correlated with power. Assuming a realistic range of prior probabilities for null hypotheses, false report probability is likely to exceed 50% for the whole literature. In light of our findings, the recently reported low replication success in psychology is realistic, and worse performance may be expected for cognitive neuroscience.
Quantifying the impact of expanded age group campaigns for polio eradication.

PubMed

Wagner, Bradley G; Behrend, Matthew R; Klein, Daniel J; Upfill-Brown, Alexander M; Eckhoff, Philip A; Hu, Hao

2014-01-01

A priority of the Global Polio Eradication Initiative (GPEI) 2013-2018 strategic plan is to evaluate the potential impact on polio eradication resulting from expanding one or more Supplementary Immunization Activities (SIAs) to children beyond age five-years in polio endemic countries. It has been hypothesized that such expanded age group (EAG) campaigns could accelerate polio eradication by eliminating immunity gaps in older children that may have resulted from past periods of low vaccination coverage. Using an individual-based mathematical model, we quantified the impact of EAG campaigns in terms of probability of elimination, reduction in polio transmission and age stratified immunity levels. The model was specifically calibrated to seroprevalence data from a polio-endemic region: Zaria, Nigeria. We compared the impact of EAG campaigns, which depend only on age, to more targeted interventions which focus on reaching missed populations. We found that EAG campaigns would not significantly improve prospects for polio eradication; the probability of elimination increased by 8% (from 24% at baseline to 32%) when expanding three annual SIAs to 5-14 year old children and by 18% when expanding all six annual SIAs. In contrast, expanding only two of the annual SIAs to target hard-to-reach populations at modest vaccination coverage-representing less than one tenth of additional vaccinations required for the six SIA EAG scenario-increased the probability of elimination by 55%. Implementation of EAG campaigns in polio endemic regions would not improve prospects for eradication. In endemic areas, vaccination campaigns which do not target missed populations will not benefit polio eradication efforts.
A modified Wald interval for the area under the ROC curve (AUC) in diagnostic case-control studies

PubMed Central

2014-01-01

Background The area under the receiver operating characteristic (ROC) curve, referred to as the AUC, is an appropriate measure for describing the overall accuracy of a diagnostic test or a biomarker in early phase trials without having to choose a threshold. There are many approaches for estimating the confidence interval for the AUC. However, all are relatively complicated to implement. Furthermore, many approaches perform poorly for large AUC values or small sample sizes. Methods The AUC is actually a probability. So we propose a modified Wald interval for a single proportion, which can be calculated on a pocket calculator. We performed a simulation study to compare this modified Wald interval (without and with continuity correction) with other intervals regarding coverage probability and statistical power. Results The main result is that the proposed modified Wald intervals maintain and exploit the type I error much better than the intervals of Agresti-Coull, Wilson, and Clopper-Pearson. The interval suggested by Bamber, the Mann-Whitney interval without transformation and also the interval of the binormal AUC are very liberal. For small sample sizes the Wald interval with continuity has a comparable coverage probability as the LT interval and higher power. For large sample sizes the results of the LT interval and of the Wald interval without continuity correction are comparable. Conclusions If individual patient data is not available, but only the estimated AUC and the total sample size, the modified Wald intervals can be recommended as confidence intervals for the AUC. For small sample sizes the continuity correction should be used. PMID:24552686
A modified Wald interval for the area under the ROC curve (AUC) in diagnostic case-control studies.

PubMed

Kottas, Martina; Kuss, Oliver; Zapf, Antonia

2014-02-19

The area under the receiver operating characteristic (ROC) curve, referred to as the AUC, is an appropriate measure for describing the overall accuracy of a diagnostic test or a biomarker in early phase trials without having to choose a threshold. There are many approaches for estimating the confidence interval for the AUC. However, all are relatively complicated to implement. Furthermore, many approaches perform poorly for large AUC values or small sample sizes. The AUC is actually a probability. So we propose a modified Wald interval for a single proportion, which can be calculated on a pocket calculator. We performed a simulation study to compare this modified Wald interval (without and with continuity correction) with other intervals regarding coverage probability and statistical power. The main result is that the proposed modified Wald intervals maintain and exploit the type I error much better than the intervals of Agresti-Coull, Wilson, and Clopper-Pearson. The interval suggested by Bamber, the Mann-Whitney interval without transformation and also the interval of the binormal AUC are very liberal. For small sample sizes the Wald interval with continuity has a comparable coverage probability as the LT interval and higher power. For large sample sizes the results of the LT interval and of the Wald interval without continuity correction are comparable. If individual patient data is not available, but only the estimated AUC and the total sample size, the modified Wald intervals can be recommended as confidence intervals for the AUC. For small sample sizes the continuity correction should be used.
Saturn's Misbegotten Moonlets

NASA Astrophysics Data System (ADS)

Spitale, Joseph N.

2017-06-01

Saturn's rings are interspersed with numerous narrow (tens of km wide) gaps. Two of the largest of these gaps -- Encke and Keeler -- contain satellites -- Pan and Daphnis -- that maintain their respective gaps via the classical Goldreich/Tremaine-style shepherding mechanism wherein angular momentum is transferred across the essentially empty gap via torques acting between the satellites and the ring. Other prominent gaps are shepherded by resonances with external satellites or planetary modes: Mimas shepherds the outer edge of the B ring, clearing the inner part of the Cassini Division, Titan shepherds the Columbo ringlet / gap, and the Maxwell ringlet / gap is likely maintained by a resonance with a planetary mode. Prior to Cassini, it was expected that all of the gaps would be shepherded in a similar manner.However, many small gaps do not correspond with known resonances, and no satellites were spotted within those gaps during Cassini's prime and extended mission. To address this issue, a series of Cassini imaging observations were planned to examine 11 gaps in the C ring and Cassini division at a resolution and longitudinal coverage sufficient to either discover the shepherds or rule out their presence. The survey discovered no embedded satellites. Longitudinal coverage was incomplete, but within longitudes covered by the survey, satellites are ruled out to sizes in the 100-m range, far too small keep the observed gaps open. It is possible (about even odds) that there could be a larger satellite residing at a longitude not covered in the survey, but the probability that the survey was unfortunate enough to miss significant satellites in all 11 gaps is exceedingly small (~0.002%). Moreover, these gaps appear in earlier imaging sequences, with some high-resolution coverage, so the true probability is smaller yet. Therefore, a new theory is likely needed to explain the presence of the gaps.
Coverage of childhood vaccination among children aged 12-23 months, Tamil Nadu, 2015, India

PubMed Central

Murhekar, Manoj V.; Kamaraj, P.; Kanagasabai, K.; Elavarasu, G.; Rajasekar, T. Daniel; Boopathi, K.; Mehendale, Sanjay

2017-01-01

Background & objectives: District-Level Household Survey-4 (DLHS-4) indicated that during 2012-2013, only 56 per cent of children aged 12-23 months in Tamil Nadu were fully vaccinated, which were lesser than those reported in earlier national surveys. We, therefore, conducted cluster surveys to estimate coverage of childhood vaccination in the State, and also to identify the factors associated with low coverage. Methods: Cross-sectional surveys were conducted in 15 strata [municipal corporation non-slum (n=1), municipal corporation slum (n=1), hilly (n=1), rural (n=6) and urban (n=6)]. From each stratum, 30 clusters were selected using probability proportional to the population size linear systematic sampling; seven children aged 12-23 months were selected from each cluster and their mothers/care-takers were interviewed to collect information about vaccination status of the child. A child was considered fully vaccinated if he/she received bacillus Calmette-Guérin (BCG), three doses of pentavalent, three doses of oral polio vaccine and one dose of measles vaccine, and appropriately vaccinated if all vaccine doses were given at right age and with right interval. Further, coverage of fully vaccinated children (FVC) as per vaccination cards or mothers’ recall, validated coverage of FVC (V-FVC) among those having cards, and coverage of appropriately vaccinated children (AVC) were estimated using survey data analysis module with appropriate sampling weights. Results: A total of 3150 children were surveyed, of them 2528 (80.3%) had vaccination card. The weighted coverage of FVC, V-FVC and AVC in the State was 79.9 per cent [95% confidence interval (CI): 78.2-81.5], 78.8 per cent (95% CI: 76.9-80.5) and 69.7 per cent (95% CI: 67.7-71.7), respectively. The coverage of individual vaccine ranged between 84 per cent (measles) and 99.8 per cent (BCG). About 12 per cent V-FVC were not vaccinated as per the vaccination schedule. Interpretation & conclusions: The coverage of FVC in Tamil Nadu was high, with about 80 per cent children completing primary vaccination. Efforts to increase vaccination coverage in the State need to focus on educating vaccinators about the need to adhere to the national vaccination schedule and strengthening supervision to ensure that children are vaccinated appropriately. PMID:28749402
Coverage of childhood vaccination among children aged 12-23 months, Tamil Nadu, 2015, India.

PubMed

Murhekar, Manoj V; Kamaraj, P; Kanagasabai, K; Elavarasu, G; Rajasekar, T Daniel; Boopathi, K; Mehendale, Sanjay

2017-03-01

District-Level Household Survey-4 (DLHS-4) indicated that during 2012-2013, only 56 per cent of children aged 12-23 months in Tamil Nadu were fully vaccinated, which were lesser than those reported in earlier national surveys. We, therefore, conducted cluster surveys to estimate coverage of childhood vaccination in the State, and also to identify the factors associated with low coverage. Cross-sectional surveys were conducted in 15 strata [municipal corporation non-slum (n=1), municipal corporation slum (n=1), hilly (n=1), rural (n=6) and urban (n=6)]. From each stratum, 30 clusters were selected using probability proportional to the population size linear systematic sampling; seven children aged 12-23 months were selected from each cluster and their mothers/care-takers were interviewed to collect information about vaccination status of the child. A child was considered fully vaccinated if he/she received bacillus Calmette-Guérin (BCG), three doses of pentavalent, three doses of oral polio vaccine and one dose of measles vaccine, and appropriately vaccinated if all vaccine doses were given at right age and with right interval. Further, coverage of fully vaccinated children (FVC) as per vaccination cards or mothers' recall, validated coverage of FVC (V-FVC) among those having cards, and coverage of appropriately vaccinated children (AVC) were estimated using survey data analysis module with appropriate sampling weights. A total of 3150 children were surveyed, of them 2528 (80.3%) had vaccination card. The weighted coverage of FVC, V-FVC and AVC in the State was 79.9 per cent [95% confidence interval (CI): 78.2-81.5], 78.8 per cent (95% CI: 76.9-80.5) and 69.7 per cent (95% CI: 67.7-71.7), respectively. The coverage of individual vaccine ranged between 84 per cent (measles) and 99.8 per cent (BCG). About 12 per cent V-FVC were not vaccinated as per the vaccination schedule. The coverage of FVC in Tamil Nadu was high, with about 80 per cent children completing primary vaccination. Efforts to increase vaccination coverage in the State need to focus on educating vaccinators about the need to adhere to the national vaccination schedule and strengthening supervision to ensure that children are vaccinated appropriately.
Radiation dose and cancer risk to out-of-field and partially in-field organs from radiotherapy for symptomatic vertebral hemangiomas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazonakis, Michalis, E-mail: mazonak@med.uoc.gr; Damilakis, John; Tzedakis, Antonis

2016-04-15

Purpose: Vertebral hemangiomas (VHs) are the most common benign tumors of the spine that may cause bone resorption. Megavoltage irradiation is usually the treatment of choice for the management of symptomatic VHs. The current study was conducted to estimate the risk for carcinogenesis from radiotherapy of this benign disease on the basis of the calculated radiation doses to healthy organs. Methods: The Monte Carlo N-particle transport code was employed to simulate the irradiation with 6 MV x-rays of a VH presented in the cervical, upper thoracic, lower thoracic, and lumbar spine. The average radiation dose (D{sub av}) received by eachmore » critical organ located outside the primarily irradiated area was calculated. Three-dimensional treatment plans were also generated for the VHs occurring at the four different sites of the spinal cord based on patients’ computed tomography data. The organ equivalent dose (OED) to each radiosensitive structure, which was partly encompassed by the applied treatment fields, was calculated with the aid of differential dose–volume histograms. The D{sub av} and the OED values were combined with a linear-no-threshold model and a nonlinear mechanistic model, respectively, to estimate the organ-, age-, and gender-specific lifetime attributable risks (LARs) for cancer development. The estimated risks were compared with the respective nominal lifetime intrinsic risks (LIRs) for the unexposed population. Results: For a standard target dose of 34 Gy, the OED varied from 0.39–5.15 Gy by the organ of interest and the irradiation site. The D{sub av} range for the out-of-field organs was 4.9 × 10{sup −4} to 0.56 Gy. The LAR for the appearance of malignancies in the partially in-field organs after radiotherapy of male and female patients was (0.08%–1.8%) and (0.09%–1.9%), respectively. These risk values were 1.5–15.5 times lower when compared to the respective LIRs. The lifetime probability for out-of-field cancer induction in irradiated males and females was (2.5 × 10{sup −4} to 7.7 × 10{sup −2})% and (1.4 × 10{sup −4} to 2.6 × 10{sup −1})%, respectively. The above risks were one to four orders of magnitude lower than the LIRs. Conclusions: The probability for the development of out-of-field malignancies due to radiotherapy for VHs is trivial with respect to the nominal risk for unexposed population. The respective cancer risks to partially in-field organs are smaller than the nominal probabilities but they should not be considered as inconsiderable. These risks may be taken into account during the follow-up of patients treated for a symptomatic VH.« less
Towards universal health coverage: an evaluation of Rwanda Mutuelles in its first eight years.

PubMed

Lu, Chunling; Chin, Brian; Lewandowski, Jiwon Lee; Basinga, Paulin; Hirschhorn, Lisa R; Hill, Kenneth; Murray, Megan; Binagwaho, Agnes

2012-01-01

Mutuelles is a community-based health insurance program, established since 1999 by the Government of Rwanda as a key component of the national health strategy on providing universal health care. The objective of the study was to evaluate the impact of Mutuelles on achieving universal coverage of medical services and financial risk protection in its first eight years of implementation. We conducted a quantitative impact evaluation of Mutuelles between 2000 and 2008 using nationally-representative surveys. At the national and provincial levels, we traced the evolution of Mutuelles coverage and its impact on child and maternal care coverage from 2000 to 2008, as well as household catastrophic health payments from 2000 to 2006. At the individual level, we investigated the impact of Mutuelles' coverage on enrollees' medical care utilization using logistic regression. We focused on three target populations: the general population, under-five children, and women with delivery. At the household level, we used logistic regression to study the relationship between Mutuelles coverage and the probability of incurring catastrophic health spending. The main limitation was that due to insufficient data, we are not able to study the impact of Mutuelles on health outcomes, such as child and maternal mortalities, directly. The findings show that Mutuelles improved medical care utilization and protected households from catastrophic health spending. Among Mutuelles enrollees, those in the poorest expenditure quintile had a significantly lower rate of utilization and higher rate of catastrophic health spending. The findings are robust to various estimation methods and datasets. Rwanda's experience suggests that community-based health insurance schemes can be effective tools for achieving universal health coverage even in the poorest settings. We suggest a future study on how eliminating Mutuelles copayments for the poorest will improve their healthcare utilization, lower their catastrophic health spending, and affect the finances of health care providers.
Towards Universal Health Coverage: An Evaluation of Rwanda Mutuelles in Its First Eight Years

PubMed Central

Lu, Chunling; Chin, Brian; Lewandowski, Jiwon Lee; Basinga, Paulin; Hirschhorn, Lisa R.; Hill, Kenneth; Murray, Megan; Binagwaho, Agnes

2012-01-01

Background Mutuelles is a community-based health insurance program, established since 1999 by the Government of Rwanda as a key component of the national health strategy on providing universal health care. The objective of the study was to evaluate the impact of Mutuelles on achieving universal coverage of medical services and financial risk protection in its first eight years of implementation. Methods and Findings We conducted a quantitative impact evaluation of Mutuelles between 2000 and 2008 using nationally-representative surveys. At the national and provincial levels, we traced the evolution of Mutuelles coverage and its impact on child and maternal care coverage from 2000 to 2008, as well as household catastrophic health payments from 2000 to 2006. At the individual level, we investigated the impact of Mutuelles' coverage on enrollees' medical care utilization using logistic regression. We focused on three target populations: the general population, under-five children, and women with delivery. At the household level, we used logistic regression to study the relationship between Mutuelles coverage and the probability of incurring catastrophic health spending. The main limitation was that due to insufficient data, we are not able to study the impact of Mutuelles on health outcomes, such as child and maternal mortalities, directly. The findings show that Mutuelles improved medical care utilization and protected households from catastrophic health spending. Among Mutuelles enrollees, those in the poorest expenditure quintile had a significantly lower rate of utilization and higher rate of catastrophic health spending. The findings are robust to various estimation methods and datasets. Conclusions Rwanda's experience suggests that community-based health insurance schemes can be effective tools for achieving universal health coverage even in the poorest settings. We suggest a future study on how eliminating Mutuelles copayments for the poorest will improve their healthcare utilization, lower their catastrophic health spending, and affect the finances of health care providers. PMID:22723985
Bayesian alternative to the ISO-GUM's use of the Welch Satterthwaite formula

NASA Astrophysics Data System (ADS)

Kacker, Raghu N.

2006-02-01

In certain disciplines, uncertainty is traditionally expressed as an interval about an estimate for the value of the measurand. Development of such uncertainty intervals with a stated coverage probability based on the International Organization for Standardization (ISO) Guide to the Expression of Uncertainty in Measurement (GUM) requires a description of the probability distribution for the value of the measurand. The ISO-GUM propagates the estimates and their associated standard uncertainties for various input quantities through a linear approximation of the measurement equation to determine an estimate and its associated standard uncertainty for the value of the measurand. This procedure does not yield a probability distribution for the value of the measurand. The ISO-GUM suggests that under certain conditions motivated by the central limit theorem the distribution for the value of the measurand may be approximated by a scaled-and-shifted t-distribution with effective degrees of freedom obtained from the Welch-Satterthwaite (W-S) formula. The approximate t-distribution may then be used to develop an uncertainty interval with a stated coverage probability for the value of the measurand. We propose an approximate normal distribution based on a Bayesian uncertainty as an alternative to the t-distribution based on the W-S formula. A benefit of the approximate normal distribution based on a Bayesian uncertainty is that it greatly simplifies the expression of uncertainty by eliminating altogether the need for calculating effective degrees of freedom from the W-S formula. In the special case where the measurand is the difference between two means, each evaluated from statistical analyses of independent normally distributed measurements with unknown and possibly unequal variances, the probability distribution for the value of the measurand is known to be a Behrens-Fisher distribution. We compare the performance of the approximate normal distribution based on a Bayesian uncertainty and the approximate t-distribution based on the W-S formula with respect to the Behrens-Fisher distribution. The approximate normal distribution is simpler and better in this case. A thorough investigation of the relative performance of the two approximate distributions would require comparison for a range of measurement equations by numerical methods.
Experimentally, How Dark Are Black Hole Mergers?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annis, James; Soares-Santos, Marcelle

2016-09-29

The first Advanced LIGO observing run detected two black hole merger events with confidence and likely a third. Many groups organized to followup the events in the optical even though the strong theoretical prior that no optical emission should be seen. We carry through the logic of this by asking about the experimental upper limits to the optical light from Advanced LIGO black hole mergere events. We inventory the published optical searches for transient events associated with the black hole mergers. We describe the factors that go into a formal limit on the visibility of an event (sky area coverage,more » the coverage factor of the camera, the fraction of sky not covered by intervening objects), and list what is known from the literature of the followup teams quantitative assessment of each factor. Where possible we calculate the total probability from each group that the source was imaged. The calculation of confidence level is reviewed for the case of no background. We find that an experimental 95% upper limit on the magnitude of a black hole requires the sum of the total probabilities over all events to be more than 3. In the first Advanced LIGO observing run we were far from reaching that threshold.« less
Who uses flexible spending accounts: effects of employee characteristics and employer strategies.

PubMed

Feldman, R; Schultz, J

2001-07-01

Many large employers offer flexible spending accounts (FSAs) to shelter their employees' out-of-pocket medical expenses from taxes and thereby to encourage the purchase of health insurance policies with higher cost sharing. However, very little empirical research has examined the individual employee's decision to contribute to an FSA. To estimate equations for the probability that single employees with no dependents and employees with family health insurance coverage will contribute to FSAs, and the amounts contributed by those with FSAs. An observational study of randomly-selected employees in 15 Minnesota firms matched with information on the strategies those firms use to promote FSAs. Measures of FSA participation were regressed on expected health care spending, employee socio-demographics, and employer strategies. 779 single employees with no dependents and 679 employees with family coverage. Education beyond high school increases the probability that both types of subjects will contribute to FSAs, with marginal effects ranging from 16 to 48 percent. The FSA contribution rate for families doubles when the family's marginal federal income tax rate increases from 15 to 28 percent. Employer strategies to encourage participation are also effective in promoting FSAs. FSAs are used mainly by high-income and highly-educated workers. We question whether this is an equitable use of the income tax code.
Potential for Rabies Control through Dog Vaccination in Wildlife-Abundant Communities of Tanzania

PubMed Central

Fitzpatrick, Meagan C.; Hampson, Katie; Cleaveland, Sarah; Meyers, Lauren Ancel; Townsend, Jeffrey P.; Galvani, Alison P.

2012-01-01

Canine vaccination has been successful in controlling rabies in diverse settings worldwide. However, concerns remain that coverage levels which have previously been sufficient might be insufficient in systems where transmission occurs both between and within populations of domestic dogs and other carnivores. To evaluate the effectiveness of vaccination targeted at domestic dogs when wildlife also contributes to transmission, we applied a next-generation matrix model based on contract tracing data from the Ngorongoro and Serengeti Districts in northwest Tanzania. We calculated corresponding values of R 0, and determined, for policy purposes, the probabilities that various annual vaccination targets would control the disease, taking into account the empirical uncertainty in our field data. We found that transition rate estimates and corresponding probabilities of vaccination-based control indicate that rabies transmission in this region is driven by transmission within domestic dogs. Different patterns of rabies transmission between the two districts exist, with wildlife playing a more important part in Ngorongoro and leading to higher recommended coverage levels in that district. Nonetheless, our findings indicate that an annual dog vaccination campaign achieving the WHO-recommended target of 70% will control rabies in both districts with a high level of certainty. Our results support the feasibility of controlling rabies in Tanzania through dog vaccination. PMID:22928056
TU-CD-304-06: Using FFF Beams Improves Tumor Control in Radiotherapy of Lung Cancers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vassiliev, O; Wang, H

Purpose: Electron disequilibrium at the lung-tumor interface results in an under-dosage of tumor regions close to its surface. This under-dosage is known to be significant and can compromise tumor control. Previous studies have shown that in FFF beams, disequilibrium effects are less pronounced, which is manifested in an increased skin dose. In this study we investigate the improvement in tumor dose coverage that can be achieved with FFF beams. The significance of this improvement is evaluated by comparing tumor control probabilities of FFF beams and conventional flattened beams. Methods: The dosimetric coverage was investigated in a virtual phantom representing themore » chest wall, lung tissue and the tumor. A range of tumor sizes was investigated, and two tumor locations – central and adjacent to the chest wall. Calculations were performed with BEAMnrc Monte Carlo code. Parallel-opposed and multiple coplanar 6-MV beams were simulated. The tumor control probabilities were calculated using the logistic model with parameters derived from clinical data for non-small lung cancer patients. Results: FFF beams were not entirely immune to disequilibrium effects. They nevertheless consistently delivered more uniform dose distribution throughout the volume of the tumor, and eliminated up to ∼15% of under-dosage in the most affected by disequilibrium 1-mm thick surface region of the tumor. A voxel-by-voxel comparison of tumor control probabilities between FFF and conventional flattened beams showed an advantage of FFF beams that, depending on the set up, was from a few to ∼9 percent. Conclusion: A modest improvement in tumor control probability on the order of a few percent can be achieved by replacing conventional flattened beams with FFF beams. However, given the large number of lung cancer patients undergoing radiotherapy, these few percent can potentially prevent local tumor recurrence for a significant number of patients.« less

Epidemiology of pertussis in two Ibero-American countries with different vaccination policies: lessons derived from different surveillance systems.

PubMed

Solano, Rubén; Masa-Calles, Josefa; Garib, Zacarías; Grullón, Patricia; Santiago, Sandy L; Brache, Altagracia; Domínguez, Ángela; Caylà, Joan A

2016-11-22

Pertussis is a re-emerging disease worldwide despite its high vaccination coverage. European and Latin-American countries have used different surveillance and vaccination policies against pertussis. We compared the epidemiology of this disease in two Ibero-American countries with different vaccination and surveillance policies. We compared the epidemiology of pertussis in Spain and the Dominican Republic (DR). We present a 10-year observational study of reported pertussis based on suspected and/or probable cases of pertussis identified by the national mandatory reporting system in both countries between 2005 and 2014. Both countries have a similar case definition for pertussis surveillance, although Spain applies laboratory testing, and uses real time PCR and/or culture for case confirmation while in DR only probable and/or suspected cases are reported. We analyzed incidence, hospitalization, case-fatality rates, mortality and vaccination coverage. The average annual incidence in children aged <1 year was 3.40/100,000 population in Spain and 12.15/100,000 in DR (p = 0.01). While the incidence in DR was generally higher than in Spain, in 2011 it was six times higher in Spain than in DR. The highest infant mortality in Spain was 0.017/100,000 in 2011, and the highest in DR was 0.08/100,000 in 2014 (p = 0.01). The proportion of hospitalized cases per year among children <1 year varied between 22.0% and 93.7% in Spain, and between 1.1% and 29.4% in DR (p = 0.0002), while mortality varied from 0 to 0.017 and 0 to 0.08 per 100,000 population in Spain and DR, respectively (p = 0.001). Vaccination coverage was 96.5% in Spain and 82.2% in DR (p = 0.001). Pertussis is a public health problem in both countries. Surveillance, prevention and control measures should be improved, especially in DR. Current vaccination programs are not sufficient for preventing continued pertussis transmission, even in Spain which has high vaccination coverage.
77 FR 52330 - Request for Additional Nominations of Candidates for the EPA's Science Advisory Board (SAB...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-29

... person or organization may nominate qualified persons to be considered for appointment to this advisory committee. Individuals may self-nominate. Nominations should be submitted in electronic format (preferred) following the instructions for ``Nominating Experts to the Chemical Assessment Advisory Committee'' provided...
76 FR 71561 - Request for Nominations of Candidates to the EPA's Science Advisory Board (SAB) Chemical...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-18

... nominate qualified persons to be considered for appointment to this advisory committee. Individuals may self-nominate. Nominations should be submitted in electronic format (preferred) following the instructions for ``Nominating Experts to the Chemical Assessment Advisory Committee'' provided on the SAB Web...
Implications of Systematic Nominator Missingness for Peer Nomination Data

ERIC Educational Resources Information Center

Babcock, Ben; Marks, Peter E. L.; van den Berg, Yvonne H. M.; Cillessen, Antonius H. N.

2018-01-01

Missing data are a persistent problem in psychological research. Peer nomination data present a unique missing data problem, because a nominator's nonparticipation results in missing data for other individuals in the study. This study examined the range of effects of systematic nonparticipation on the correlations between peer nomination data when…
Nominalizations in Spanish. Studies in Linguistics and Language Learning, Volume V.

ERIC Educational Resources Information Center

Falk, Julia Sableski

Using methods developed in transformational generative grammar, three types of nominal constructions in Spanish are treated in this paper: Fact nominalizations ("[El] Escribir es agradable"), Manner nominalizations ("El tocar [de la mujer] es agradable"), and Abstract noun nominalizations ("La construccion rapida de esta escuela es dudosa"). While…
New options for national population surveys: The implications of internet and smartphone coverage.

PubMed

Couper, Mick P; Gremel, Garret; Axinn, William; Guyer, Heidi; Wagner, James; West, Brady T

2018-07-01

Challenges to survey data collection have increased the costs of social research via face-to-face surveys so much that it may become extremely difficult for social scientists to continue using these methods. A key drawback to less expensive Internet-based alternatives is the threat of biased results from coverage errors in survey data. The rise of Internet-enabled smartphones presents an opportunity to re-examine the issue of Internet coverage for surveys and its implications for coverage bias. Two questions (on Internet access and smartphone ownership) were added to the National Survey of Family Growth (NSFG), a U.S. national probability survey of women and men age 15-44, using a continuous sample design. We examine 16 quarters (4 years) of data, from September 2012 to August 2016. Overall, we estimate that 82.9% of the target NSFG population has Internet access, and 81.6% has a smartphone. Combined, this means that about 90.7% of U.S. residents age 15-44 have Internet access, via either traditional devices or a smartphone. We find some evidence of compensatory coverage when looking at key race/ethnicity and age subgroups. For instance, while Black teens (15-18) have the lowest estimated rate of Internet access (81.9%) and the lowest rate of smartphone usage (72.6%), an estimated 88.0% of this subgroup has some form of Internet access. We also examine the socio-demographic correlates of Internet and smartphone coverage, separately and combined, as indicators of technology access in this population. In addition, we look at the effect of differential coverage on key estimates produced by the NSFG, related to fertility, family formation, and sexual activity. While this does not address nonresponse or measurement biases that may differ for alternative modes, our paper has implications for possible coverage biases that may arise when switching to a Web-based mode of data collection, either for follow-up surveys or to replace the main face-to-face data collection. Copyright © 2018. Published by Elsevier Inc.
Societal implications of medical insurance coverage for imatinib as first-line treatment of chronic myeloid leukemia in China: a cost-effectiveness analysis.

PubMed

Sheng, Guangying; Chen, Suning; Dong, Chaohui; Zhang, Ri; Miao, Miao; Wu, Depei; Tan, Seng Chuen; Liu, Chao; Xiong, Tengbin

2017-04-01

Imatinib (Glivec) and nilotinib (Tasigna) have been covered by critical disease insurance in Jiangsu province of China since 2013, which changed local treatment patterns and outcomes of patients with chronic myeloid leukemia (CML). This study evaluated the long-term cost-effectiveness of insurance coverage with imatinib as the first-line treatment for patients with CML in China from a societal perspective. A decision-analytic model based on previously published and real-world evidence was applied to simulate and evaluate the lifetime clinical and economic outcomes associated with CML treatments before and after imatinib was covered by medical insurance. Incremental cost-effectiveness ratio (ICER) was calculated with both costs and quality-adjusted life years (QALYs) discounted at 3% annually. Different assumptions of treatment benefits and costs were taken to address uncertainties and were tested with sensitivity analyses. In base case analysis, both cost and effectiveness of CML treatments increased after imatinib was covered by the medical insurance; on average, the incremental QALY and cost were 5.5 and ¥277,030 per patient in lifetime, respectively. The ICER of insurance coverage with imatinib was ¥50,641, which is less than the GDP per capita of China. Monte Carlo simulation resulted in the estimate of 100% probability that the insurance coverage of imatinib is cost-effective. Total cost was substantially saved at 5 years after patients initiated imatinib treatment with insurance coverage compared to no insurance coverage, the saved cost at 5 years was ¥99,565, which included the cost savings from both direct (e.g. cost of bone marrow or stem cell transplant) and indirect costs (e.g. productivity loss of patients and care-givers). The insurance coverage of imatinib is very cost-effective in China, according to the local cost and clinical data in Jiangsu province. More importantly, the insurance coverage of imatinib and nilotinib have changed the treatment patterns of CML patients, thus dramatically increasing life expectancy and quality-of-life (QoL) saving on productivity losses for both CML patients and their caregivers.
Accuracy and impact of spatial aids based upon satellite enumeration to improve indoor residual spraying spatial coverage.

PubMed

Bridges, Daniel J; Pollard, Derek; Winters, Anna M; Winters, Benjamin; Sikaala, Chadwick; Renn, Silvia; Larsen, David A

2018-02-23

Indoor residual spraying (IRS) is a key tool in the fight to control, eliminate and ultimately eradicate malaria. IRS protection is based on a communal effect such that an individual's protection primarily relies on the community-level coverage of IRS with limited protection being provided by household-level coverage. To ensure a communal effect is achieved through IRS, achieving high and uniform community-level coverage should be the ultimate priority of an IRS campaign. Ensuring high community-level coverage of IRS in malaria-endemic areas is challenging given the lack of information available about both the location and number of households needing IRS in any given area. A process termed 'mSpray' has been developed and implemented and involves use of satellite imagery for enumeration for planning IRS and a mobile application to guide IRS implementation. This study assessed (1) the accuracy of the satellite enumeration and (2) how various degrees of spatial aid provided through the mSpray process affected community-level IRS coverage during the 2015 spray campaign in Zambia. A 2-stage sampling process was applied to assess accuracy of satellite enumeration to determine number and location of sprayable structures. Results indicated an overall sensitivity of 94% for satellite enumeration compared to finding structures on the ground. After adjusting for structure size, roof, and wall type, households in Nchelenge District where all types of satellite-based spatial aids (paper-based maps plus use of the mobile mSpray application) were used were more likely to have received IRS than Kasama district where maps used were not based on satellite enumeration. The probability of a household being sprayed in Nchelenge district where tablet-based maps were used, did not differ statistically from that of a household in Samfya District, where detailed paper-based spatial aids based on satellite enumeration were provided. IRS coverage from the 2015 spray season benefited from the use of spatial aids based upon satellite enumeration. These spatial aids can guide costly IRS planning and implementation leading to attainment of higher spatial coverage, and likely improve disease impact.
Cost-effectiveness of canine vaccination to prevent human rabies in rural Tanzania.

PubMed

Fitzpatrick, Meagan C; Hampson, Katie; Cleaveland, Sarah; Mzimbiri, Imam; Lankester, Felix; Lembo, Tiziana; Meyers, Lauren A; Paltiel, A David; Galvani, Alison P

2014-01-21

The annual mortality rate of human rabies in rural Africa is 3.6 deaths per 100 000 persons. Rabies can be prevented with prompt postexposure prophylaxis, but this is costly and often inaccessible in rural Africa. Because 99% of human exposures occur through rabid dogs, canine vaccination also prevents transmission of rabies to humans. To evaluate the cost-effectiveness of rabies control through annual canine vaccination campaigns in rural sub-Saharan Africa. We model transmission dynamics in dogs and wildlife and assess empirical uncertainty in the biological variables to make probability-based evaluations of cost-effectiveness. Epidemiologic variables from a contact-tracing study and literature and cost data from ongoing vaccination campaigns. Two districts of rural Tanzania: Ngorongoro and Serengeti. 10 years. Health policymaker. Vaccination coverage ranging from 0% to 95% in increments of 5%. Life-years for health outcomes and 2010 U.S. dollars for economic outcomes. Annual canine vaccination campaigns were very cost-effective in both districts compared with no canine vaccination. In Serengeti, annual campaigns with as much as 70% coverage were cost-saving. Across a wide range of variable assumptions and levels of societal willingness to pay for life-years, the optimal vaccination coverage for Serengeti was 70%. In Ngorongoro, although optimal coverage depended on willingness to pay, vaccination campaigns were always cost-effective and lifesaving and therefore preferred. Canine vaccination was very cost-effective in both districts, but there was greater uncertainty about the optimal coverage in Ngorongoro. Annual canine rabies vaccination campaigns conferred extraordinary value and dramatically reduced the health burden of rabies. National Institutes of Health.
Expanding Lipidome Coverage Using LC-MS/MS Data-Dependent Acquisition with Automated Exclusion List Generation

NASA Astrophysics Data System (ADS)

Koelmel, Jeremy P.; Kroeger, Nicholas M.; Gill, Emily L.; Ulmer, Candice Z.; Bowden, John A.; Patterson, Rainey E.; Yost, Richard A.; Garrett, Timothy J.

2017-05-01

Untargeted omics analyses aim to comprehensively characterize biomolecules within a biological system. Changes in the presence or quantity of these biomolecules can indicate important biological perturbations, such as those caused by disease. With current technological advancements, the entire genome can now be sequenced; however, in the burgeoning fields of lipidomics, only a subset of lipids can be identified. The recent emergence of high resolution tandem mass spectrometry (HR-MS/MS), in combination with ultra-high performance liquid chromatography, has resulted in an increased coverage of the lipidome. Nevertheless, identifications from MS/MS are generally limited by the number of precursors that can be selected for fragmentation during chromatographic elution. Therefore, we developed the software IE-Omics to automate iterative exclusion (IE), where selected precursors using data-dependent topN analyses are excluded in sequential injections. In each sequential injection, unique precursors are fragmented until HR-MS/MS spectra of all ions above a user-defined intensity threshold are acquired. IE-Omics was applied to lipidomic analyses in Red Cross plasma and substantia nigra tissue. Coverage of the lipidome was drastically improved using IE. When applying IE-Omics to Red Cross plasma and substantia nigra lipid extracts in positive ion mode, 69% and 40% more molecular identifications were obtained, respectively. In addition, applying IE-Omics to a lipidomics workflow increased the coverage of trace species, including odd-chained and short-chained diacylglycerides and oxidized lipid species. By increasing the coverage of the lipidome, applying IE to a lipidomics workflow increases the probability of finding biomarkers and provides additional information for determining etiology of disease.
Elimination of African onchocerciasis: modeling the impact of increasing the frequency of ivermectin mass treatment.

PubMed

Coffeng, Luc E; Stolk, Wilma A; Hoerauf, Achim; Habbema, Dik; Bakker, Roel; Hopkins, Adrian D; de Vlas, Sake J

2014-01-01

The African Programme for Onchocerciasis Control (APOC) is currently shifting its focus from morbidity control to elimination of infection. To enhance the likelihood of elimination and speed up its achievement, programs may consider to increase the frequency of ivermectin mass treatment from annual to 6-monthly or even higher. In a computer simulation study, we examined the potential impact of increasing the mass treatment frequency for different settings. With the ONCHOSIM model, we simulated 92,610 scenarios pertaining to different assumptions about transmission conditions, history of mass treatment, the future mass treatment strategy, and ivermectin efficacy. Simulation results were used to determine the minimum remaining program duration and number of treatment rounds required to achieve 99% probability of elimination. Doubling the frequency of treatment from yearly to 6-monthly or 3-monthly was predicted to reduce remaining program duration by about 40% or 60%, respectively. These reductions come at a cost of additional treatment rounds, especially in case of 3-monthly mass treatment. Also, aforementioned reductions are highly dependent on maintained coverage, and could be completely nullified if coverage of mass treatment were to fall in the future. In low coverage settings, increasing treatment coverage is almost just as effective as increasing treatment frequency. We conclude that 6-monthly mass treatment may only be worth the effort in situations where annual treatment is expected to take a long time to achieve elimination in spite of good treatment coverage, e.g. because of unfavorable transmission conditions or because mass treatment started recently.
A stochastic model for the probability of malaria extinction by mass drug administration.

PubMed

Pemberton-Ross, Peter; Chitnis, Nakul; Pothin, Emilie; Smith, Thomas A

2017-09-18

Mass drug administration (MDA) has been proposed as an intervention to achieve local extinction of malaria. Although its effect on the reproduction number is short lived, extinction may subsequently occur in a small population due to stochastic fluctuations. This paper examines how the probability of stochastic extinction depends on population size, MDA coverage and the reproduction number under control, R c . A simple compartmental model is developed which is used to compute the probability of extinction using probability generating functions. The expected time to extinction in small populations after MDA for various scenarios in this model is calculated analytically. The results indicate that mass drug administration (Firstly, R c must be sustained at R c < 1.2 to avoid the rapid re-establishment of infections in the population. Secondly, the MDA must produce effective cure rates of >95% to have a non-negligible probability of successful elimination. Stochastic fluctuations only significantly affect the probability of extinction in populations of about 1000 individuals or less. The expected time to extinction via stochastic fluctuation is less than 10 years only in populations less than about 150 individuals. Clustering of secondary infections and of MDA distribution both contribute positively to the potential probability of success, indicating that MDA would most effectively be administered at the household level. There are very limited circumstances in which MDA will lead to local malaria elimination with a substantial probability.
Vaccination and All-Cause Child Mortality From 1985 to 2011: Global Evidence From the Demographic and Health Surveys

PubMed Central

McGovern, Mark E.; Canning, David

2015-01-01

Based on models with calibrated parameters for infection, case fatality rates, and vaccine efficacy, basic childhood vaccinations have been estimated to be highly cost effective. We estimated the association of vaccination with mortality directly from survey data. Using 149 cross-sectional Demographic and Health Surveys, we determined the relationship between vaccination coverage and the probability of dying between birth and 5 years of age at the survey cluster level. Our data included approximately 1 million children in 68,490 clusters from 62 countries. We considered the childhood measles, bacillus Calmette-Guérin, diphtheria-pertussis-tetanus, polio, and maternal tetanus vaccinations. Using modified Poisson regression to estimate the relative risk of child mortality in each cluster, we also adjusted for selection bias that resulted from the vaccination status of dead children not being reported. Childhood vaccination, and in particular measles and tetanus vaccination, is associated with substantial reductions in childhood mortality. We estimated that children in clusters with complete vaccination coverage have a relative risk of mortality that is 0.73 (95% confidence interval: 0.68, 0.77) times that of children in a cluster with no vaccinations. Although widely used, basic vaccines still have coverage rates well below 100% in many countries, and our results emphasize the effectiveness of increasing coverage rates in order to reduce child mortality. PMID:26453618
Primary Health Care Utilization by the Mexican Indigenous Population: The Role of the Seguro Popular in Socially Inequitable Contexts

PubMed Central

Leyva-Flores, Rene; Servan-Mori, Edson; Infante-Xibille, Cesar; Pelcastre-Villafuerte, Blanca Estela; Gonzalez, Tonatiuh

2014-01-01

Objective To analyze the relationship between primary health care utilization and extended health insurance coverage under the Seguro Popular (SP) among Mexican indigenous people. Methodology A cross-sectional analysis was conducted using data from the Mexican National Nutrition Survey 2012 (n = 194,758). Quasi-experimental matching methods and nonlinear regression probit models were used to estimate the influence of SP on primary health care utilization. Results 25% of the Mexican population reported having no health insurance coverage, while 59% of indigenous versus 35% of non-indigenous reported having SP coverage. Health problems were reported by 13.9% of indigenous vs. 10.5% of non-indigenous; of these, 52.8% and 57.7% respectively, received primary health care (p<0.05). Economic barriers were the most frequent reasons for not using primary health care services. The probability of utilizing primary health care services was 11.5 percentage points higher (p<0.01) for indigenous SP affiliates in comparison with non-indigenous, in similar socioeconomic conditions. Conclusion Socioeconomic conditions, not ethnicity per-se, determine whether people utilize primary health care services. Therefore, SP can be conceived as a public policy strategy which acts as a social buffer by enhancing health care utilization regardless of ethnicity. Further analysis is required to explore the potential gaps as a result of SP coverage among socially vulnerable groups. PMID:25099399
Convective Weather Forecast Quality Metrics for Air Traffic Management Decision-Making

NASA Technical Reports Server (NTRS)

Chatterji, Gano B.; Gyarfas, Brett; Chan, William N.; Meyn, Larry A.

2006-01-01

Since numerical weather prediction models are unable to accurately forecast the severity and the location of the storm cells several hours into the future when compared with observation data, there has been a growing interest in probabilistic description of convective weather. The classical approach for generating uncertainty bounds consists of integrating the state equations and covariance propagation equations forward in time. This step is readily recognized as the process update step of the Kalman Filter algorithm. The second well known method, known as the Monte Carlo method, consists of generating output samples by driving the forecast algorithm with input samples selected from distributions. The statistical properties of the distributions of the output samples are then used for defining the uncertainty bounds of the output variables. This method is computationally expensive for a complex model compared to the covariance propagation method. The main advantage of the Monte Carlo method is that a complex non-linear model can be easily handled. Recently, a few different methods for probabilistic forecasting have appeared in the literature. A method for computing probability of convection in a region using forecast data is described in Ref. 5. Probability at a grid location is computed as the fraction of grid points, within a box of specified dimensions around the grid location, with forecast convection precipitation exceeding a specified threshold. The main limitation of this method is that the results are dependent on the chosen dimensions of the box. The examples presented Ref. 5 show that this process is equivalent to low-pass filtering of the forecast data with a finite support spatial filter. References 6 and 7 describe the technique for computing percentage coverage within a 92 x 92 square-kilometer box and assigning the value to the center 4 x 4 square-kilometer box. This technique is same as that described in Ref. 5. Characterizing the forecast, following the process described in Refs. 5 through 7, in terms of percentage coverage or confidence level is notionally sound compared to characterizing in terms of probabilities because the probability of the forecast being correct can only be determined using actual observations. References 5 through 7 only use the forecast data and not the observations. The method for computing the probability of detection, false alarm ratio and several forecast quality metrics (Skill Scores) using both the forecast and observation data are given in Ref. 2. This paper extends the statistical verification method in Ref. 2 to determine co-occurrence probabilities. The method consists of computing the probability that a severe weather cell (grid location) is detected in the observation data in the neighborhood of the severe weather cell in the forecast data. Probabilities of occurrence at the grid location and in its neighborhood with higher severity, and with lower severity in the observation data compared to that in the forecast data are examined. The method proposed in Refs. 5 through 7 is used for computing the probability that a certain number of cells in the neighborhood of severe weather cells in the forecast data are seen as severe weather cells in the observation data. Finally, the probability of existence of gaps in the observation data in the neighborhood of severe weather cells in forecast data is computed. Gaps are defined as openings between severe weather cells through which an aircraft can safely fly to its intended destination. The rest of the paper is organized as follows. Section II summarizes the statistical verification method described in Ref. 2. The extension of this method for computing the co-occurrence probabilities in discussed in Section HI. Numerical examples using NCWF forecast data and NCWD observation data are presented in Section III to elucidate the characteristics of the co-occurrence probabilities. This section also discusses the procedure for computing throbabilities that the severity of convection in the observation data will be higher or lower in the neighborhood of grid locations compared to that indicated at the grid locations in the forecast data. The probability of coverage of neighborhood grid cells is also described via examples in this section. Section IV discusses the gap detection algorithm and presents a numerical example to illustrate the method. The locations of the detected gaps in the observation data are used along with the locations of convective weather cells in the forecast data to determine the probability of existence of gaps in the neighborhood of these cells. Finally, the paper is concluded in Section V.
Electrical characteristics and step coverage of ZrO2 films deposited by atomic layer deposition for through-silicon via and metal-insulator-metal applications

NASA Astrophysics Data System (ADS)

Choi, Kyeong-Keun; Park, Chan-Gyung; Kim, Deok-kee

2016-01-01

The electrical characteristics and step coverage of ZrO2 films deposited by atomic layer deposition were investigated for through-silicon via (TSV) and metal-insulator-metal applications at temperatures below 300 °C. ZrO2 films were able to be conformally deposited on the scallops of 50-µm-diameter, 100-µm-deep TSV holes. The mean breakdown field of 30-nm-thick ZrO2 films on 30-nm-thick Ta(N) increased about 41% (from 2.7 to 3.8 MV/cm) upon H2 plasma treatment. With the plasma treatment, the breakdown field of the film increased and the temperature coefficient of capacitance decreased significantly, probably as a result of the decreased carbon concentration in the film.
75 FR 43933 - Request for nominations for members to serve on National Institute of Standards and Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-27

... duties. Selection of ISPAB members will not be limited to individuals who are nominated. Nominations that.... Selection of MEP Advisory Board members will not be limited to individuals who are nominated. Nominations... in its official role as the private sector policy advisor of the Institute is concerned. Each such...
77 FR 40332 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-09

... duties. Selection of ISPAB members will not be limited to individuals who are nominated. Nominations that... to individuals who are nominated. Nominations that are received and meet the requirements will be... policy advisor of NIST is concerned. Each such report shall identify areas of program emphasis for NIST...
78 FR 67121 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-08

... to individuals who are nominated. Nominations that are received and meet the requirements will be.... Selection of MEP Advisory Board members will not be limited to individuals who are nominated. Nominations... official role as the private sector policy adviser of NIST is concerned. Each such report shall identify...
Questions and answers on employee benefit issues.

PubMed

1994-06-01

This Issue Brief addresses 19 topics in the areas of pensions, health insurance, and other benefits. In addition to the topics listed below, the report includes data on the prevalence of benefits, tax incentives associated with benefits, lump-sum distributions, number of private pension plans, pension coverage rates, 401(k) plans, employer spending on group health insurance, self-insured health plans, employer initiatives to reduce health care costs, and employers' response to the retiree health benefits accounting rule, and flexible benefits plans. In 1992, U.S. employers (public and private) spent $629 billion for noncash benefits, representing nearly 18 percent of total compensation, excluding paid time off. In 1992, 71 percent of the 50.1 million individuals aged 55 and over received retirement benefits, including distributions from private and public pensions, annuities, individual retirement accounts, Keoghs, 401(k)s, and Social Security. Among the 76 percent of all private pension plan participants who participated in a single plan, 30 percent named a defined benefit plan as their pension plan type, 58 percent named a defined contribution plan as their pension plan type, and 12 percent did not know their plan type. Private and public pension funds held more than $4.6 trillion in assets at the end of 1993. The 1993 year-end assets are more than triple the asset level of 1983 (nominal terms). According to the Congressional Budget Office, U.S. expenditures on health care were expected to have reached $898 billion in 1993, up from $751.8 billion in 1991, an increase of 19.4 percent in nominal terms.

African Programme for Onchocerciasis Control 1995–2015: Model-Estimated Health Impact and Cost

PubMed Central

Coffeng, Luc E.; Stolk, Wilma A.; Zouré, Honorat G. M.; Veerman, J. Lennert; Agblewonu, Koffi B.; Murdoch, Michele E.; Noma, Mounkaila; Fobi, Grace; Richardus, Jan Hendrik; Bundy, Donald A. P.; Habbema, Dik; de Vlas, Sake J.; Amazigo, Uche V.

2013-01-01

Background Onchocerciasis causes a considerable disease burden in Africa, mainly through skin and eye disease. Since 1995, the African Programme for Onchocerciasis Control (APOC) has coordinated annual mass treatment with ivermectin in 16 countries. In this study, we estimate the health impact of APOC and the associated costs from a program perspective up to 2010 and provide expected trends up to 2015. Methods and Findings With data on pre-control prevalence of infection and population coverage of mass treatment, we simulated trends in infection, blindness, visual impairment, and severe itch using the micro-simulation model ONCHOSIM, and estimated disability-adjusted life years (DALYs) lost due to onchocerciasis. We assessed financial costs for APOC, beneficiary governments, and non-governmental development organizations, excluding cost of donated drugs. We estimated that between 1995 and 2010, mass treatment with ivermectin averted 8.2 million DALYs due to onchocerciasis in APOC areas, at a nominal cost of about US$257 million. We expect that APOC will avert another 9.2 million DALYs between 2011 and 2015, at a nominal cost of US$221 million. Conclusions Our simulations suggest that APOC has had a remarkable impact on population health in Africa between 1995 and 2010. This health impact is predicted to double during the subsequent five years of the program, through to 2015. APOC is a highly cost-effective public health program. Given the anticipated elimination of onchocerciasis from some APOC areas, we expect even more health gains and a more favorable cost-effectiveness of mass treatment with ivermectin in the near future. PMID:23383355
African Programme For Onchocerciasis Control 1995-2015: model-estimated health impact and cost.

PubMed

Coffeng, Luc E; Stolk, Wilma A; Zouré, Honorat G M; Veerman, J Lennert; Agblewonu, Koffi B; Murdoch, Michele E; Noma, Mounkaila; Fobi, Grace; Richardus, Jan Hendrik; Bundy, Donald A P; Habbema, Dik; de Vlas, Sake J; Amazigo, Uche V

2013-01-01

Onchocerciasis causes a considerable disease burden in Africa, mainly through skin and eye disease. Since 1995, the African Programme for Onchocerciasis Control (APOC) has coordinated annual mass treatment with ivermectin in 16 countries. In this study, we estimate the health impact of APOC and the associated costs from a program perspective up to 2010 and provide expected trends up to 2015. With data on pre-control prevalence of infection and population coverage of mass treatment, we simulated trends in infection, blindness, visual impairment, and severe itch using the micro-simulation model ONCHOSIM, and estimated disability-adjusted life years (DALYs) lost due to onchocerciasis. We assessed financial costs for APOC, beneficiary governments, and non-governmental development organizations, excluding cost of donated drugs. We estimated that between 1995 and 2010, mass treatment with ivermectin averted 8.2 million DALYs due to onchocerciasis in APOC areas, at a nominal cost of about US$257 million. We expect that APOC will avert another 9.2 million DALYs between 2011 and 2015, at a nominal cost of US$221 million. Our simulations suggest that APOC has had a remarkable impact on population health in Africa between 1995 and 2010. This health impact is predicted to double during the subsequent five years of the program, through to 2015. APOC is a highly cost-effective public health program. Given the anticipated elimination of onchocerciasis from some APOC areas, we expect even more health gains and a more favorable cost-effectiveness of mass treatment with ivermectin in the near future.
Yellow Fever in Africa: estimating the burden of disease and impact of mass vaccination from outbreak and serological data.

PubMed

Garske, Tini; Van Kerkhove, Maria D; Yactayo, Sergio; Ronveaux, Olivier; Lewis, Rosamund F; Staples, J Erin; Perea, William; Ferguson, Neil M

2014-05-01

Yellow fever is a vector-borne disease affecting humans and non-human primates in tropical areas of Africa and South America. While eradication is not feasible due to the wildlife reservoir, large scale vaccination activities in Africa during the 1940s to 1960s reduced yellow fever incidence for several decades. However, after a period of low vaccination coverage, yellow fever has resurged in the continent. Since 2006 there has been substantial funding for large preventive mass vaccination campaigns in the most affected countries in Africa to curb the rising burden of disease and control future outbreaks. Contemporary estimates of the yellow fever disease burden are lacking, and the present study aimed to update the previous estimates on the basis of more recent yellow fever occurrence data and improved estimation methods. Generalised linear regression models were fitted to a dataset of the locations of yellow fever outbreaks within the last 25 years to estimate the probability of outbreak reports across the endemic zone. Environmental variables and indicators for the surveillance quality in the affected countries were used as covariates. By comparing probabilities of outbreak reports estimated in the regression with the force of infection estimated for a limited set of locations for which serological surveys were available, the detection probability per case and the force of infection were estimated across the endemic zone. The yellow fever burden in Africa was estimated for the year 2013 as 130,000 (95% CI 51,000-380,000) cases with fever and jaundice or haemorrhage including 78,000 (95% CI 19,000-180,000) deaths, taking into account the current level of vaccination coverage. The impact of the recent mass vaccination campaigns was assessed by evaluating the difference between the estimates obtained for the current vaccination coverage and for a hypothetical scenario excluding these vaccination campaigns. Vaccination campaigns were estimated to have reduced the number of cases and deaths by 27% (95% CI 22%-31%) across the region, achieving up to an 82% reduction in countries targeted by these campaigns. A limitation of our study is the high level of uncertainty in our estimates arising from the sparseness of data available from both surveillance and serological surveys. With the estimation method presented here, spatial estimates of transmission intensity can be combined with vaccination coverage levels to evaluate the impact of past or proposed vaccination campaigns, thereby helping to allocate resources efficiently for yellow fever control. This method has been used by the Global Alliance for Vaccines and Immunization (GAVI Alliance) to estimate the potential impact of future vaccination campaigns.
Yellow Fever in Africa: Estimating the Burden of Disease and Impact of Mass Vaccination from Outbreak and Serological Data

PubMed Central

Garske, Tini; Van Kerkhove, Maria D.; Yactayo, Sergio; Ronveaux, Olivier; Lewis, Rosamund F.; Staples, J. Erin; Perea, William; Ferguson, Neil M.

2014-01-01

Background Yellow fever is a vector-borne disease affecting humans and non-human primates in tropical areas of Africa and South America. While eradication is not feasible due to the wildlife reservoir, large scale vaccination activities in Africa during the 1940s to 1960s reduced yellow fever incidence for several decades. However, after a period of low vaccination coverage, yellow fever has resurged in the continent. Since 2006 there has been substantial funding for large preventive mass vaccination campaigns in the most affected countries in Africa to curb the rising burden of disease and control future outbreaks. Contemporary estimates of the yellow fever disease burden are lacking, and the present study aimed to update the previous estimates on the basis of more recent yellow fever occurrence data and improved estimation methods. Methods and Findings Generalised linear regression models were fitted to a dataset of the locations of yellow fever outbreaks within the last 25 years to estimate the probability of outbreak reports across the endemic zone. Environmental variables and indicators for the surveillance quality in the affected countries were used as covariates. By comparing probabilities of outbreak reports estimated in the regression with the force of infection estimated for a limited set of locations for which serological surveys were available, the detection probability per case and the force of infection were estimated across the endemic zone. The yellow fever burden in Africa was estimated for the year 2013 as 130,000 (95% CI 51,000–380,000) cases with fever and jaundice or haemorrhage including 78,000 (95% CI 19,000–180,000) deaths, taking into account the current level of vaccination coverage. The impact of the recent mass vaccination campaigns was assessed by evaluating the difference between the estimates obtained for the current vaccination coverage and for a hypothetical scenario excluding these vaccination campaigns. Vaccination campaigns were estimated to have reduced the number of cases and deaths by 27% (95% CI 22%–31%) across the region, achieving up to an 82% reduction in countries targeted by these campaigns. A limitation of our study is the high level of uncertainty in our estimates arising from the sparseness of data available from both surveillance and serological surveys. Conclusions With the estimation method presented here, spatial estimates of transmission intensity can be combined with vaccination coverage levels to evaluate the impact of past or proposed vaccination campaigns, thereby helping to allocate resources efficiently for yellow fever control. This method has been used by the Global Alliance for Vaccines and Immunization (GAVI Alliance) to estimate the potential impact of future vaccination campaigns. Please see later in the article for the Editors' Summary PMID:24800812
The role of the deep space network's frequency and timing system in the detection of gravitational waves

NASA Technical Reports Server (NTRS)

Mankins, J. C.

1982-01-01

A review of the Deep Space Network's (DSN) use of precision Doppler-tracking of deep space vehicles is presented. The review emphasizes operational and configurational aspects and considers: the projected configuration of the DSN's frequency and timing system; the environment within the DSN provided by the precision atomic standards within the frequency and timing system--both current and projected; and the general requirements placed on the DSN and the frequency and timing system for both the baseline and the nominal gravitational wave experiments. A comment is made concerning the current probability that such an experiment will be carried out in the foreseeable future.
Translational velocity oscillations of piston generated vortex rings

NASA Astrophysics Data System (ADS)

Kumar, Manoj; Arakeri, J. H.; Shankar, P. N.

1995-11-01

Experimental results are presented that show that the translational velocities of piston generated vortex rings often undergo oscillations, similar to those recently discovered for drop generated rings. An attempt has been made to minimize uncertainties by utilizing both dye and hydrogen bubbles for visualization and carefully repeating measurements on the same ring and on different realizations under the same nominal piston conditions. The results unambiguously show that under most conditions, both for laminar and turbulent rings and for rings generated from pipes and orifices, the oscillations are present. The present results, together with the earlier results on drop generated rings, give support to the view that translational velocity oscillations are probably an inherent feature of translating vortex ring fields.
Ground radar detection of meteoroids in space

NASA Technical Reports Server (NTRS)

Kessler, D. J.; Landry, P. M.; Gabbard, J. R.; Moran, J. L. T.

1980-01-01

A special test to lower the detection threshold for satellite fragments potentially dangerous to spacecraft was carried out by NORAD for NASA, using modified radar software. The Perimeter Acquisition Radar Attack Characterization System, a large, planar face, phased radar, operates at a nominal 430 MHz and produces 120 pulses per second, 45 of which were dedicated to search. In a time period of 8.4 hours of observations over three days, over 6000 objects were detected and tracked of which 37 were determined to have velocities greater than escape velocity. Six of these were larger objects with radar cross sections greater than 0.1 sq m and were probably orbiting satellites. A table gives the flux of both observed groups.
Marine Microcosm Experiments on Effects of Copper and Tributylin-Based Antifouling Paint Leachates

DTIC Science & Technology

1988-06-01

consumers in HliOrg microcosms were probably the thick carpets of green algae ( Cladophora socialis) that developed in those tanks during leachate and...and bottom substrate in the SPG-4 tanks were dominated by a low-diversity community composed primarily of Cladophora socialis, a filamentous green...coverage and diversity of species after 4 weeks of’ exposure. Moderate to thick growths of filamentous green algae ( Cladophora socialis) covered with
76 FR 39379 - Request for Nominations for Members To Serve on National Institute of Standards and Technology...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-06

... will not be limited to individuals who are nominated. Nominations that are received and meet the... individuals who are nominated. Nominations that are received and meet the requirements will be kept on file to... in its official role as the private sector policy advisor of the Institute is concerned. Each such...
Variance estimation when using inverse probability of treatment weighting (IPTW) with survival analysis.

PubMed

Austin, Peter C

2016-12-30

Propensity score methods are used to reduce the effects of observed confounding when using observational data to estimate the effects of treatments or exposures. A popular method of using the propensity score is inverse probability of treatment weighting (IPTW). When using this method, a weight is calculated for each subject that is equal to the inverse of the probability of receiving the treatment that was actually received. These weights are then incorporated into the analyses to minimize the effects of observed confounding. Previous research has found that these methods result in unbiased estimation when estimating the effect of treatment on survival outcomes. However, conventional methods of variance estimation were shown to result in biased estimates of standard error. In this study, we conducted an extensive set of Monte Carlo simulations to examine different methods of variance estimation when using a weighted Cox proportional hazards model to estimate the effect of treatment. We considered three variance estimation methods: (i) a naïve model-based variance estimator; (ii) a robust sandwich-type variance estimator; and (iii) a bootstrap variance estimator. We considered estimation of both the average treatment effect and the average treatment effect in the treated. We found that the use of a bootstrap estimator resulted in approximately correct estimates of standard errors and confidence intervals with the correct coverage rates. The other estimators resulted in biased estimates of standard errors and confidence intervals with incorrect coverage rates. Our simulations were informed by a case study examining the effect of statin prescribing on mortality. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.
Estimating Consequences of MMOD Penetrations on ISS

NASA Technical Reports Server (NTRS)

Evans, H.; Hyde, James; Christiansen, E.; Lear, D.

2017-01-01

The threat from micrometeoroid and orbital debris (MMOD) impacts on space vehicles is often quantified in terms of the probability of no penetration (PNP). However, for large spacecraft, especially those with multiple compartments, a penetration may have a number of possible outcomes. The extent of the damage (diameter of hole, crack length or penetration depth), the location of the damage relative to critical equipment or crew, crew response, and even the time of day of the penetration are among the many factors that can affect the outcome. For the International Space Station (ISS), a Monte-Carlo style software code called Manned Spacecraft Crew Survivability (MSCSurv) is used to predict the probability of several outcomes of an MMOD penetration-broadly classified as loss of crew (LOC), crew evacuation (Evac), loss of escape vehicle (LEV), and nominal end of mission (NEOM). By generating large numbers of MMOD impacts (typically in the billions) and tracking the consequences, MSCSurv allows for the inclusion of a large number of parameters and models as well as enabling the consideration of uncertainties in the models and parameters. MSCSurv builds upon the results from NASA's Bumper software (which provides the probability of penetration and critical input data to MSCSurv) to allow analysts to estimate the probability of LOC, Evac, LEV, and NEOM. This paper briefly describes the overall methodology used by NASA to quantify LOC, Evac, LEV, and NEOM with particular emphasis on describing in broad terms how MSCSurv works and its capabilities and most significant models.
Predicting the Consequences of MMOD Penetrations on the International Space Station

NASA Technical Reports Server (NTRS)

Hyde, James; Christiansen, E.; Lear, D.; Evans

2018-01-01

The threat from micrometeoroid and orbital debris (MMOD) impacts on space vehicles is often quantified in terms of the probability of no penetration (PNP). However, for large spacecraft, especially those with multiple compartments, a penetration may have a number of possible outcomes. The extent of the damage (diameter of hole, crack length or penetration depth), the location of the damage relative to critical equipment or crew, crew response, and even the time of day of the penetration are among the many factors that can affect the outcome. For the International Space Station (ISS), a Monte-Carlo style software code called Manned Spacecraft Crew Survivability (MSCSurv) is used to predict the probability of several outcomes of an MMOD penetration-broadly classified as loss of crew (LOC), crew evacuation (Evac), loss of escape vehicle (LEV), and nominal end of mission (NEOM). By generating large numbers of MMOD impacts (typically in the billions) and tracking the consequences, MSCSurv allows for the inclusion of a large number of parameters and models as well as enabling the consideration of uncertainties in the models and parameters. MSCSurv builds upon the results from NASA's Bumper software (which provides the probability of penetration and critical input data to MSCSurv) to allow analysts to estimate the probability of LOC, Evac, LEV, and NEOM. This paper briefly describes the overall methodology used by NASA to quantify LOC, Evac, LEV, and NEOM with particular emphasis on describing in broad terms how MSCSurv works and its capabilities and most significant models.
Determination of the measurement threshold in gamma-ray spectrometry.

PubMed

Korun, M; Vodenik, B; Zorko, B

2017-03-01

In gamma-ray spectrometry the measurement threshold describes the lover boundary of the interval of peak areas originating in the response of the spectrometer to gamma-rays from the sample measured. In this sense it presents a generalization of the net indication corresponding to the decision threshold, which is the measurement threshold at the quantity value zero for a predetermined probability for making errors of the first kind. Measurement thresholds were determined for peaks appearing in the spectra of radon daughters 214 Pb and 214 Bi by measuring the spectrum 35 times under repeatable conditions. For the calculation of the measurement threshold the probability for detection of the peaks and the mean relative uncertainty of the peak area were used. The relative measurement thresholds, the ratios between the measurement threshold and the mean peak area uncertainty, were determined for 54 peaks where the probability for detection varied between some percent and about 95% and the relative peak area uncertainty between 30% and 80%. The relative measurement thresholds vary considerably from peak to peak, although the nominal value of the sensitivity parameter defining the sensitivity for locating peaks was equal for all peaks. At the value of the sensitivity parameter used, the peak analysis does not locate peaks corresponding to the decision threshold with the probability in excess of 50%. This implies that peaks in the spectrum may not be located, although the true value of the measurand exceeds the decision threshold. Copyright © 2017 Elsevier Ltd. All rights reserved.
Monte Carlo based protocol for cell survival and tumour control probability in BNCT.

PubMed

Ye, S J

1999-02-01

A mathematical model to calculate the theoretical cell survival probability (nominally, the cell survival fraction) is developed to evaluate preclinical treatment conditions for boron neutron capture therapy (BNCT). A treatment condition is characterized by the neutron beam spectra, single or bilateral exposure, and the choice of boron carrier drug (boronophenylalanine (BPA) or boron sulfhydryl hydride (BSH)). The cell survival probability defined from Poisson statistics is expressed with the cell-killing yield, the 10B(n,alpha)7Li reaction density, and the tolerable neutron fluence. The radiation transport calculation from the neutron source to tumours is carried out using Monte Carlo methods: (i) reactor-based BNCT facility modelling to yield the neutron beam library at an irradiation port; (ii) dosimetry to limit the neutron fluence below a tolerance dose (10.5 Gy-Eq); (iii) calculation of the 10B(n,alpha)7Li reaction density in tumours. A shallow surface tumour could be effectively treated by single exposure producing an average cell survival probability of 10(-3)-10(-5) for probable ranges of the cell-killing yield for the two drugs, while a deep tumour will require bilateral exposure to achieve comparable cell kills at depth. With very pure epithermal beams eliminating thermal, low epithermal and fast neutrons, the cell survival can be decreased by factors of 2-10 compared with the unmodified neutron spectrum. A dominant effect of cell-killing yield on tumour cell survival demonstrates the importance of choice of boron carrier drug. However, these calculations do not indicate an unambiguous preference for one drug, due to the large overlap of tumour cell survival in the probable ranges of the cell-killing yield for the two drugs. The cell survival value averaged over a bulky tumour volume is used to predict the overall BNCT therapeutic efficacy, using a simple model of tumour control probability (TCP).
The ranking probability approach and its usage in design and analysis of large-scale studies.

PubMed

Kuo, Chia-Ling; Zaykin, Dmitri

2013-01-01

In experiments with many statistical tests there is need to balance type I and type II error rates while taking multiplicity into account. In the traditional approach, the nominal [Formula: see text]-level such as 0.05 is adjusted by the number of tests, [Formula: see text], i.e., as 0.05/[Formula: see text]. Assuming that some proportion of tests represent "true signals", that is, originate from a scenario where the null hypothesis is false, power depends on the number of true signals and the respective distribution of effect sizes. One way to define power is for it to be the probability of making at least one correct rejection at the assumed [Formula: see text]-level. We advocate an alternative way of establishing how "well-powered" a study is. In our approach, useful for studies with multiple tests, the ranking probability [Formula: see text] is controlled, defined as the probability of making at least [Formula: see text] correct rejections while rejecting hypotheses with [Formula: see text] smallest P-values. The two approaches are statistically related. Probability that the smallest P-value is a true signal (i.e., [Formula: see text]) is equal to the power at the level [Formula: see text], to an very good excellent approximation. Ranking probabilities are also related to the false discovery rate and to the Bayesian posterior probability of the null hypothesis. We study properties of our approach when the effect size distribution is replaced for convenience by a single "typical" value taken to be the mean of the underlying distribution. We conclude that its performance is often satisfactory under this simplification; however, substantial imprecision is to be expected when [Formula: see text] is very large and [Formula: see text] is small. Precision is largely restored when three values with the respective abundances are used instead of a single typical effect size value.
Reinterpreting the importance of oxygen-based biodegradation in chloroethene-contaminated groundwater

USGS Publications Warehouse

Bradley, Paul M.

2011-01-01

Chlororespiration is common in shallow aquifer systems under conditions nominally identified as anoxic. Consequently, chlororespiration is a key component of remediation at many chloroethene-contaminated sites. In some instances, limited accumulation of reductive dechlorination daughter products is interpreted as evidence that natural attenuation is not adequate for site remediation. This conclusion is justified when evidence for parent compound (tetrachloroethene, PCE, or trichloroethene, TCE) degradation is lacking. For many chloroethene-contaminated shallow aquifer systems, however, nonconservative losses of the parent compounds are clear but the mass balance between parent compound attenuation and accumulation of reductive dechlorination daughter products is incomplete. Incomplete mass balance indicates a failure to account for important contaminant attenuation mechanisms and is consistent with contaminant degradation to nondiagnostic mineralization products like CO2. While anoxic mineralization of chloroethene compounds has been proposed previously, recent results suggest that oxygen-based mineralization of chloroethenes also can be significant at dissolved oxygen concentrations below the currently accepted field standard for nominally anoxic conditions. Thus, reassessment of the role and potential importance of low concentrations of oxygen in chloroethene biodegradation are needed, because mischaracterization of operant biodegradation processes can lead to expensive and ineffective remedial actions. A modified interpretive framework is provided for assessing the potential for chloroethene biodegradation under different redox conditions and the probable role of oxygen in chloroethene biodegradation.
Mars Flyer Rocket Propulsion Risk Assessment: ARC Testing

NASA Technical Reports Server (NTRS)

2001-01-01

This report describes the investigation of a 10-N, bipropellant thruster, operating at -40 C, with monomethy1hydrazine (MMH) and 25% nitric oxide in nitrogen tetroxide (MON-25). The thruster testing was conducted as part of a risk reduction activity for the Mars Flyer, a proposed mission to fly a miniature airplane in the Martian atmosphere. Testing was conducted using an existing thruster, designed for MMH and MON-3 propellants. MON-25 oxidizer was successfully manufactured from MON-3 by the addition of nitric oxide. The thruster was operated successfully over a range of propellant temperatures (-40 to 21 C and feed pressures (6.9 to 20.7 kPa). The thruster hardware was always equal or lower than the propellant temperature. Most tests were 30- and 60-second durations, with 600- and 1200-second duration and pulse testing also conducted. When operating at -40 C, the mixture ratio of the thruster shifted from the nominal value of 1.65 to about 1.85, probably caused by an increase in MMH viscosity, with a corresponding reduction in MMH flowrate. Specific impulse at - 40 C (at nominal feed pressures) was 267 sec, while performance was 277 sec at 21 C. This difference in performance was due, in part, to the mixture ratio shift.
Conceptual and linguistic representations of kinds and classes

PubMed Central

Prasada, Sandeep; Hennefield, Laura; Otap, Daniel

2013-01-01

We investigate the hypothesis that our conceptual systems provide two formally distinct ways of representing categories by investigating the manner in which lexical nominals (e.g., tree, picnic table) and phrasal nominals (e.g., black bird, birds that like rice) are interpreted. Four experiments found that lexical nominals may be mapped onto kind representations whereas phrasal nominals map onto class representations but not kind representations. Experiment 1 found that phrasal nominals, unlike lexical nominals, are mapped onto categories whose members need not be of a single kind. Experiments 2 and 3 found that categories named by lexical nominals enter into both class inclusion and kind hierarchies and thus support both class inclusion (is a) and kind specification (kind of) relations, whereas phrasal nominals map onto class representations which support only class inclusion relations. Experiment 4 showed that the two types of nominals represent hierarchical relations in different ways. Phrasal nominals (e.g., white bear) are mapped onto classes that have criteria of membership in addition to those specified by the class picked out by the head noun of the phrase (e.g., bear). In contrast, lexical nominals (e.g., polar bear) specify one way to meet the criteria specified by the more general kind concept (e.g., bear). Implications for the language-conceptual system interface, representation of hierarchical relations, lexicalization, and theories of conceptual combination are discussed. PMID:22671567
7 CFR 917.18 - Nomination of commodity committee members of the Control Committee.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Administrative Bodies § 917.18 Nomination of commodity committee members of the Control Committee. Nominations... committee shall be entitled to nominate shall be based upon the proportion that the previous three fiscal...
7 CFR 917.18 - Nomination of commodity committee members of the Control Committee.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Administrative Bodies § 917.18 Nomination of commodity committee members of the Control Committee. Nominations... committee shall be entitled to nominate shall be based upon the proportion that the previous three fiscal...

7 CFR 917.18 - Nomination of commodity committee members of the Control Committee.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Administrative Bodies § 917.18 Nomination of commodity committee members of the Control Committee. Nominations... committee shall be entitled to nominate shall be based upon the proportion that the previous three fiscal...
7 CFR 917.18 - Nomination of commodity committee members of the Control Committee.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Administrative Bodies § 917.18 Nomination of commodity committee members of the Control Committee. Nominations... committee shall be entitled to nominate shall be based upon the proportion that the previous three fiscal...
7 CFR 917.18 - Nomination of commodity committee members of the Control Committee.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Administrative Bodies § 917.18 Nomination of commodity committee members of the Control Committee. Nominations... committee shall be entitled to nominate shall be based upon the proportion that the previous three fiscal...
Assessing potential enrollment and budgetary effects of SCHIP premiums: findings from Arizona and Kentucky.

PubMed

Kenney, Genevieve; Marton, James; McFeeters, Joshua; Costich, Julia

2007-12-01

To assess whether new premiums in SCHIP affect rates of disenrollment and reenrollment in SCHIP and whether they have spillover enrollment effects on Medicaid. We used SCHIP administrative enrollment data from Arizona and Kentucky. The enrollment data covered July 2001 to December 2005 in Arizona and November 2001 to August 2004 in Kentucky. We used administrative data from two states, Arizona and Kentucky, which introduced new premiums for certain income categories in their SCHIP programs in 2004 and 2003, respectively. We used multivariate hazard models to study rates of disenrollment and re-enrollment for the recipients who had been enrolled in the categories of SCHIP in which the new premiums were implemented. Competing hazard models were used to determine if recipients leaving SCHIP following the introduction of the premium were obtaining other public coverage or exiting public insurance entirely at higher rates. We also used time-series models to measure the effect of premiums on changes in caseloads in premium-paying SCHIP and other categories of public coverage and we assessed the budgetary implications of imposing premiums. In both states, the new premiums increased the rate of disenrollment and decreased the rate of re-enrollment in premium-paying SCHIP among the children who were enrolled in those categories before the premiums were implemented. The competing hazard models indicated that almost all of the increased disenrollment is caused by recipients leaving public insurance entirely. The time-series models indicated that the new premium reduced caseloads in premium-paying SCHIP, but that it might have increased caseloads for other types of public coverage. The amount of premiums collected net of the costs associated with administering premiums is small in both states. Estimating the full budgetary effects with certainty was not possible given the imprecision of the key time-series estimates. These results suggest that the new premium reduced enrollment in the premium-paying group by 18 percent (over 3,000 children) in Kentucky and by 5 percent (over 1,000 children) in Arizona, with some of these children apparently leaving public coverage altogether. While most children enrolled in these categories did not appear to be directly affected by the imposition of $10-$20 monthly premiums, the premiums may have caused some children to go without health insurance coverage, which in turn could have adverse effects on their access to care. Imposing nominal premiums may reduce state spending, but projected savings appear to be small relative to total state SCHIP spending and resulting increases in enrollment in other public programs and in uninsurance rates could offset those savings.
Goal-Function Tree Modeling for Systems Engineering and Fault Management

NASA Technical Reports Server (NTRS)

Patterson, Jonathan D.; Johnson, Stephen B.

2013-01-01

The draft NASA Fault Management (FM) Handbook (2012) states that Fault Management (FM) is a "part of systems engineering", and that it "demands a system-level perspective" (NASAHDBK- 1002, 7). What, exactly, is the relationship between systems engineering and FM? To NASA, systems engineering (SE) is "the art and science of developing an operable system capable of meeting requirements within often opposed constraints" (NASA/SP-2007-6105, 3). Systems engineering starts with the elucidation and development of requirements, which set the goals that the system is to achieve. To achieve these goals, the systems engineer typically defines functions, and the functions in turn are the basis for design trades to determine the best means to perform the functions. System Health Management (SHM), by contrast, defines "the capabilities of a system that preserve the system's ability to function as intended" (Johnson et al., 2011, 3). Fault Management, in turn, is the operational subset of SHM, which detects current or future failures, and takes operational measures to prevent or respond to these failures. Failure, in turn, is the "unacceptable performance of intended function." (Johnson 2011, 605) Thus the relationship of SE to FM is that SE defines the functions and the design to perform those functions to meet system goals and requirements, while FM detects the inability to perform those functions and takes action. SHM and FM are in essence "the dark side" of SE. For every function to be performed (SE), there is the possibility that it is not successfully performed (SHM); FM defines the means to operationally detect and respond to this lack of success. We can also describe this in terms of goals: for every goal to be achieved, there is the possibility that it is not achieved; FM defines the means to operationally detect and respond to this inability to achieve the goal. This brief description of relationships between SE, SHM, and FM provide hints to a modeling approach to provide formal connectivity between the nominal (SE), and off-nominal (SHM and FM) aspects of functions and designs. This paper describes a formal modeling approach to the initial phases of the development process that integrates the nominal and off-nominal perspectives in a model that unites SE goals and functions of with the failure to achieve goals and functions (SHM/FM). This methodology and corresponding model, known as a Goal-Function Tree (GFT), provides a means to represent, decompose, and elaborate system goals and functions in a rigorous manner that connects directly to design through use of state variables that translate natural language requirements and goals into logical-physical state language. The state variable-based approach also provides the means to directly connect FM to the design, by specifying the range in which state variables must be controlled to achieve goals, and conversely, the failures that exist if system behavior go out-of-range. This in turn allows for the systems engineers and SHM/FM engineers to determine which state variables to monitor, and what action(s) to take should the system fail to achieve that goal. In sum, the GFT representation provides a unified approach to early-phase SE and FM development. This representation and methodology has been successfully developed and implemented using Systems Modeling Language (SysML) on the NASA Space Launch System (SLS) Program. It enabled early design trade studies of failure detection coverage to ensure complete detection coverage of all crew-threatening failures. The representation maps directly both to FM algorithm designs, and to failure scenario definitions needed for design analysis and testing. The GFT representation provided the basis for mapping of abort triggers into scenarios, both needed for initial, and successful quantitative analyses of abort effectiveness (detection and response to crew-threatening events).
ISRO's dual frequency airborne SAR pre-cursor to NISAR

NASA Astrophysics Data System (ADS)

Ramanujam, V. Manavala; Suneela, T. J. V. D.; Bhan, Rakesh

2016-05-01

The Indian Space Research Organisation (ISRO) and the National Aeronautics and Space Administration (NASA) have jointly embarked on NASA-ISRO Synthetic Aperture Radar (NISAR) operating in L-band and S-band, which will map Earth's surface every 12 days. As a pre-cursor to the NISAR mission, ISRO is planning an airborne SAR (L&S band) which will deliver NISAR analogue data products to the science community. ISRO will develop all the hardware with the aim of adhering to system design aspects of NISAR to the maximum extent possible. It is a fully polarimetric stripmap SAR and can be operated in single, dual, compact, quasi-quad and full polarimetry modes. It has wide incidence angle coverage from 24°-77° with swath coverage from 5.5km to 15 km. Apart from simultaneous imaging operations, this system can also operate in standalone L/S SAR modes. This system is planned to operate from an aircraft platform with nominal altitude of 8000meters. Antenna for this SAR will be rigidly mounted to the aircraft, whereas, motion compensation will be implemented in the software processor to generate data products. Data products for this airborne SAR will be generated in slant & ground range azimuth dimension and geocoded in HDF5/Geotiff formats. This airborne SAR will help to prepare the Indian scientific community for optimum utilization of NISAR data. In-order to collect useful science data, airborne campaigns are planned from end of 2016 onwards.
Generalized Bootstrap Method for Assessment of Uncertainty in Semivariogram Inference

USGS Publications Warehouse

Olea, R.A.; Pardo-Iguzquiza, E.

2011-01-01

The semivariogram and its related function, the covariance, play a central role in classical geostatistics for modeling the average continuity of spatially correlated attributes. Whereas all methods are formulated in terms of the true semivariogram, in practice what can be used are estimated semivariograms and models based on samples. A generalized form of the bootstrap method to properly model spatially correlated data is used to advance knowledge about the reliability of empirical semivariograms and semivariogram models based on a single sample. Among several methods available to generate spatially correlated resamples, we selected a method based on the LU decomposition and used several examples to illustrate the approach. The first one is a synthetic, isotropic, exhaustive sample following a normal distribution, the second example is also a synthetic but following a non-Gaussian random field, and a third empirical sample consists of actual raingauge measurements. Results show wider confidence intervals than those found previously by others with inadequate application of the bootstrap. Also, even for the Gaussian example, distributions for estimated semivariogram values and model parameters are positively skewed. In this sense, bootstrap percentile confidence intervals, which are not centered around the empirical semivariogram and do not require distributional assumptions for its construction, provide an achieved coverage similar to the nominal coverage. The latter cannot be achieved by symmetrical confidence intervals based on the standard error, regardless if the standard error is estimated from a parametric equation or from bootstrap. ?? 2010 International Association for Mathematical Geosciences.
44 CFR 150.3 - Nomination process.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Section 150.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall...) Civil defense officer (or member of a recognized civil defense or emergency preparedness organization...
44 CFR 150.3 - Nomination process.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Section 150.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall...) Civil defense officer (or member of a recognized civil defense or emergency preparedness organization...
44 CFR 150.3 - Nomination process.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Section 150.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall...) Civil defense officer (or member of a recognized civil defense or emergency preparedness organization...
44 CFR 150.3 - Nomination process.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 150.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall...) Civil defense officer (or member of a recognized civil defense or emergency preparedness organization...
44 CFR 150.3 - Nomination process.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Section 150.3 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... Nomination process. (a) The Nominating Officials nominating Firefighters and Civil Defense Officers shall...) Civil defense officer (or member of a recognized civil defense or emergency preparedness organization...
77 FR 19056 - Information Reporting Program Advisory Committee (IRPAC); Nominations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-29

... DEPARTMENT OF TREASURY Internal Revenue Service Information Reporting Program Advisory Committee (IRPAC); Nominations AGENCY: Internal Revenue Service, Department of Treasury. ACTION: Request for Nominations. SUMMARY: The Internal Revenue Service (IRS) requests nominations of individuals for selection to...
78 FR 19582 - Information Reporting Program Advisory Committee (IRPAC); Nominations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-01

... DEPARTMENT OF TREASURY Internal Revenue Service Information Reporting Program Advisory Committee (IRPAC); Nominations AGENCY: Internal Revenue Service, Department of Treasury. ACTION: Request for Nominations. SUMMARY: The Internal Revenue Service (IRS) requests nominations of individuals for selection to...
Sampling considerations for disease surveillance in wildlife populations

USGS Publications Warehouse

Nusser, S.M.; Clark, W.R.; Otis, D.L.; Huang, L.

2008-01-01

Disease surveillance in wildlife populations involves detecting the presence of a disease, characterizing its prevalence and spread, and subsequent monitoring. A probability sample of animals selected from the population and corresponding estimators of disease prevalence and detection provide estimates with quantifiable statistical properties, but this approach is rarely used. Although wildlife scientists often assume probability sampling and random disease distributions to calculate sample sizes, convenience samples (i.e., samples of readily available animals) are typically used, and disease distributions are rarely random. We demonstrate how landscape-based simulation can be used to explore properties of estimators from convenience samples in relation to probability samples. We used simulation methods to model what is known about the habitat preferences of the wildlife population, the disease distribution, and the potential biases of the convenience-sample approach. Using chronic wasting disease in free-ranging deer (Odocoileus virginianus) as a simple illustration, we show that using probability sample designs with appropriate estimators provides unbiased surveillance parameter estimates but that the selection bias and coverage errors associated with convenience samples can lead to biased and misleading results. We also suggest practical alternatives to convenience samples that mix probability and convenience sampling. For example, a sample of land areas can be selected using a probability design that oversamples areas with larger animal populations, followed by harvesting of individual animals within sampled areas using a convenience sampling method.
Statistical Significance and Baseline Monitoring.

DTIC Science & Technology

1984-07-01

impacted at once........................... 24 6 Observed versus nominal a levels for multivariate tests of data sets (50 runs of 4 groups each...cumulative proportion of the observations found for each nominal level. The results of the comparisons of the observed versus nominal a levels for the...a values are always higher than nominal levels. Virtual- . .,ly all nominal a levels are below 0.20. In other words, the discriminant analysis models
Think globally, act locally: the role of local demographics and vaccination coverage in the dynamic response of measles infection to control.

PubMed

Ferrari, M J; Grenfell, B T; Strebel, P M

2013-08-05

The global reduction of the burden of morbidity and mortality owing to measles has been a major triumph of public health. However, the continued persistence of measles infection probably not only reflects local variation in progress towards vaccination target goals, but may also reflect local variation in dynamic processes of transmission, susceptible replenishment through births and stochastic local extinction. Dynamic models predict that vaccination should increase the mean age of infection and increase inter-annual variability in incidence. Through a comparative approach, we assess national-level patterns in the mean age of infection and measles persistence. We find that while the classic predictions do hold in general, the impact of vaccination on the age distribution of cases and stochastic fadeout are mediated by local birth rate. Thus, broad-scale vaccine coverage goals are unlikely to have the same impact on the interruption of measles transmission in all demographic settings. Indeed, these results suggest that the achievement of further measles reduction or elimination goals is likely to require programmatic and vaccine coverage goals that are tailored to local demographic conditions.
Walking peptide on Au(110) surface: Origin and nature of interfacial process

NASA Astrophysics Data System (ADS)

Humblot, V.; Tejeda, A.; Landoulsi, J.; Vallée, A.; Naitabdi, A.; Taleb, A.; Pradier, C.-M.

2014-10-01

IGF tri-peptide adsorption on Au(110)-(1 × 2) under Ultra High Vacuum (UHV) conditions has been investigated using surface science techniques such as synchrotron based Angle Resolved X-ray Photoemission Spectroscopy (AR-PES or AR-XPS), Low Energy Electron Diffraction (LEED) and Scanning Tunnelling Microscopy (STM). The behaviour of IGF molecules has been revealed to be coverage dependent; at low coverage, there is formation of islands presenting a chiral self-organised molecular network with a (4 2, - 3 2) symmetry as shown by Low Energy Electron Diffraction (LEED) and Scanning Tunnelling Microscopy (STM) on the unaltered Au(110)-(1 × 2) reconstruction, suggesting significant intermolecular interactions. When the coverage is increased, the islands grow bigger, and one can observe the disappearance of the self-organised network, along with a remarkable destruction of the (1 × 2) substrate reconstruction, as shown by STM. The effect of IGF on the surface gold atoms has been further confirmed by angle-resolved photoemission measurements which suggest a modification of the electronic states with the (1 × 2) symmetry. The resulting molecular organisation, and overall the gold surface disorganisation, prove a strong surface-molecule interaction, which may be probably be explained by a covalent bonding.
Perceptions of randomized security schedules.

PubMed

Scurich, Nicholas; John, Richard S

2014-04-01

Security of infrastructure is a major concern. Traditional security schedules are unable to provide omnipresent coverage; consequently, adversaries can exploit predictable vulnerabilities to their advantage. Randomized security schedules, which randomly deploy security measures, overcome these limitations, but public perceptions of such schedules have not been examined. In this experiment, participants were asked to make a choice between attending a venue that employed a traditional (i.e., search everyone) or a random (i.e., a probability of being searched) security schedule. The absolute probability of detecting contraband was manipulated (i.e., 1/10, 1/4, 1/2) but equivalent between the two schedule types. In general, participants were indifferent to either security schedule, regardless of the probability of detection. The randomized schedule was deemed more convenient, but the traditional schedule was considered fairer and safer. There were no differences between traditional and random schedule in terms of perceived effectiveness or deterrence. Policy implications for the implementation and utilization of randomized schedules are discussed. © 2013 Society for Risk Analysis.
Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

PubMed Central

Grimaldi, Claudio

2017-01-01

The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor than a futile attempt. Here we insist that even if extraterrestrial civilizations do exist and communicate, the likelihood of detecting their signals crucially depends on whether the Earth lies within a region of the galaxy covered by such signals. By considering possible populations of independent emitters in the galaxy, we build a statistical model of the domain covered by hypothetical extraterrestrial signals to derive the detection probability that the Earth is within such a domain. We show that for general distributions of the signal longevity and directionality, the mean number of detectable emitters is less than one even for detection probabilities as large as 50%, regardless of the number of emitters in the galaxy. PMID:28401943

76 FR 52016 - NASA Federal Advisory Committees; Nominations and Self-Nominations

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-19

... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice: (11- 075)] NASA Federal Advisory Committees; Nominations and Self- Nominations AGENCY: National Aeronautics and Space Administration. ACTION: Public... the Federal Advisory Committee Act, Public Law 92-463, as amended, the National Aeronautics and Space...
7 CFR 987.124 - Nomination and polling.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Nomination and polling. 987.124 Section 987.124 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing... IN RIVERSIDE COUNTY, CALIFORNIA Administrative Rules Nominations § 987.124 Nomination and polling. (a...
7 CFR 1150.133 - Nominations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 9 2012-01-01 2012-01-01 false Nominations. 1150.133 Section 1150.133 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order National Dairy Promotion and Research Board § 1150.133 Nominations. Nominations for members of the...
7 CFR 1150.133 - Nominations.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 9 2013-01-01 2013-01-01 false Nominations. 1150.133 Section 1150.133 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Order National Dairy Promotion and Research Board § 1150.133 Nominations. Nominations for members of the...
NekNominate: Social Norms, Social Media, and Binge Drinking.

PubMed

Wombacher, Kevin; Reno, Jenna E; Veil, Shari R

2017-05-01

This study examines the social-media-based binge drinking game NekNominate and how this phenomenon is related to social norms. NekNominate is a game wherein players are nominated to film themselves "neking" or chugging copious amounts of alcohol or drinking alcohol in a novel or humorous manner. The player then nominates other players via social media who then have a specific timeframe in which they must complete their challenge or face ridicule. Health communication research on drinking behaviors has often looked at the role of social norms in determining these behaviors. News stories (n = 44) of NekNominate and tweets (n = 851) culled using the hashtag #NekNominate during three different time periods are analyzed to identify the normative forces at play in this recent phenomenon.
Xenogenic collagen matrix or autologous connective tissue graft as adjunct to coronally advanced flaps for coverage of multiple adjacent gingival recession: Randomized trial assessing non-inferiority in root coverage and superiority in oral health-related quality of life.

PubMed

Tonetti, Maurizio S; Cortellini, Pierpaolo; Pellegrini, Gaia; Nieri, Michele; Bonaccini, Daniele; Allegri, Mario; Bouchard, Philippe; Cairo, Francesco; Conforti, Gianpaolo; Fourmousis, Ioannis; Graziani, Filippo; Guerrero, Adrian; Halben, Jan; Malet, Jacques; Rasperini, Giulio; Topoll, Heinz; Wachtel, Hannes; Wallkamm, Beat; Zabalegui, Ion; Zuhr, Otto

2018-01-01

To evaluate the non-inferiority of the adjunct of a xenogeneic collagen matrix (CMX) or connective tissue graft (CTG) to coronally advanced flaps (CAF) for coverage of multiple adjacent recessions and compare superiority in patient-reported outcomes (PROM). One hundred and eighty-seven subjects (92 CMX) with 485 recessions in 14 centres were randomized and followed up for 6 months. Patients filled daily diaries for 15 days to monitor patient-reported experience. The primary outcome was changed in position of the gingival margin. Multilevel analysis used centre, subject and tooth as levels and baseline parameters as covariates. Average baseline recession was 2.5 ± 1.0 mm. The surgery was 15.7 min shorter (95%CI from 11.9 to 19.6, p < .0001) and perceived lighter (11.9 VAS units, 95%CI from 4.6 to 19.1, p = .0014) in CMX subjects. Time to recovery was 1.8 days shorter in CMX. Six-month root coverage was 1.7 ± 1.1 mm for CMX and 2.1 ± 1.0 mm for CTG (difference of 0.44 mm, 95%CI from 0.25 to 0.63 mm). The upper limit of the confidence interval was over the non-inferiority margin of 0.25 mm. Odds of complete root coverage were significantly higher for CTG (OR = 4.0, 95% CI 1.8-8.8). Replacing CTG with CMX shortens time to recovery and decreases morbidity, but the tested generation of devices is probably inferior to autologous CTG in terms of root coverage. Significant variability in PROMs was observed among centres. © 2017 The Authors. Journal of Clinical Periodontology Published by John Wiley & Sons Ltd.
[Fair health financing and catastrophic health expenditures: potential impact of the coverage extension of the popular health insurance in Mexico].

PubMed

Knaul, Felicia; Arreola-Ornelas, Héctor; Méndez, Oscar; Martínez, Alejandra

2005-01-01

To assess the impact on fair health financing and household catastrophic health expenditures of the implementation of the Popular Health Insurance (Seguro Popular de Salud). Data analyzed in this study come from the National Income and Expenditure Household Survey (Encuesta Nacional de Ingresos y Gastos de los Hogares, ENIGH), 2000, and the National Health Insurance and Expenditure Survey, (Encuesta Nacional de Aseguramiento y Gasto en Salud, ENAGS), 2001. Estimations are based on projections of extension of the Popular Health Insurance under different conditions of coverage and out-of-pocket expenditure reductions in the uninsured population. The mathematic simulation model assumes applying the new Popular Health Insurance financial structure to the 2000 expenditure values reported by ENIGH, given the probability of affiliation by households. The model of determinants of affiliation to the Popular Health Insurance yielded three significant variables: being in income quintiles I and II, being a female head of household, and that a household member had a medical visit in the past year. Simulation results show that important impacts on the performance of the Mexican Health System will occur in terms of fair financing and catastrophic expenditures, even before achieving the universal coverage goal in 2010. A reduction of 40% in out-of-pocket expenditures and a Popular Health Insurance coverage of 100% will decrease catastrophic health expenditures from 3.4% to 1.6%. Our results show that the reduction of out-of-pocket expenditures generated by the new financing and health provision Popular Health Insurance model, will improve the financial fairness index and the financial contribution to the health system, and will decrease the percentage of households with catastrophic expenditures, even before reaching universal coverage. A greater impact may be expected due to coverage extension initiating in the poorest communities that have a very restricted and progressive financial contribution.
Modelling the cost-effectiveness of mass screening and treatment for reducing Plasmodium falciparum malaria burden.

PubMed

Crowell, Valerie; Briët, Olivier J T; Hardy, Diggory; Chitnis, Nakul; Maire, Nicolas; Di Pasquale, Aurelio; Smith, Thomas A

2013-01-03

Past experience and modelling suggest that, in most cases, mass treatment strategies are not likely to succeed in interrupting Plasmodium falciparum malaria transmission. However, this does not preclude their use to reduce disease burden. Mass screening and treatment (MSAT) is preferred to mass drug administration (MDA), as the latter involves massive over-use of drugs. This paper reports simulations of the incremental cost-effectiveness of well-conducted MSAT campaigns as a strategy for P. falciparum malaria disease-burden reduction in settings with varying receptivity (ability of the combined vector population in a setting to transmit disease) and access to case management. MSAT incremental cost-effectiveness ratios (ICERs) were estimated in different sub-Saharan African settings using simulation models of the dynamics of malaria and a literature-based MSAT cost estimate. Imported infections were simulated at a rate of two per 1,000 population per annum. These estimates were compared to the ICERs of scaling up case management or insecticide-treated net (ITN) coverage in each baseline health system, in the absence of MSAT. MSAT averted most episodes, and resulted in the lowest ICERs, in settings with a moderate level of disease burden. At a low pre-intervention entomological inoculation rate (EIR) of two infectious bites per adult per annum (IBPAPA) MSAT was never more cost-effective than scaling up ITNs or case management coverage. However, at pre-intervention entomological inoculation rates (EIRs) of 20 and 50 IBPAPA and ITN coverage levels of 40 or 60%, respectively, the ICER of MSAT was similar to that of scaling up ITN coverage further. In all the transmission settings considered, achieving a minimal level of ITN coverage is a "best buy". At low transmission, MSAT probably is not worth considering. Instead, MSAT may be suitable at medium to high levels of transmission and at moderate ITN coverage. If undertaken as a burden-reducing intervention, MSAT should be continued indefinitely and should complement, not replace, case management and vector control interventions.
Rural water supply and sanitation (RWSS) coverage in Swaziland: Toward achieving millennium development goals

NASA Astrophysics Data System (ADS)

Mwendera, E. J.

An assessment of rural water supply and sanitation (RWSS) coverage in Swaziland was conducted in 2004/2005 as part of the Rural Water Supply and Sanitation Initiative (RWSSI). The initiative was developed by the African Development Bank with the aim of implementing it in the Regional Member Countries (RMCs), including Swaziland. Information on the RWSS sector programmes, costs, financial requirements and other related activities was obtained from a wide range of national documents, including sector papers and project files and progress reports. Interviews were held with staff from the central offices and field stations of Government of Swaziland (GOS) ministries and departments, non-governmental organizations (NGOs), bilateral and multilateral external support agencies, and private sector individuals and firms with some connection to the sector and/or its programmes. The assessment also involved field visits to various regions in order to obtain first hand information about the various technologies and institutional structures used in the provision of water supplies and sanitation services in the rural areas of the country. The results showed that the RWSS sector has made significant progress towards meeting the national targets of providing water and sanitation to the entire rural population by the year 2022. The assessment indicated that rural water supply coverage was 56% in 2004 while sanitation coverage was 63% in the same year. The results showed that there is some decline in the incidence of water-related diseases, such as diarrhoeal diseases, probably due to improved water supply and sanitation coverage. The study also showed that, with adequate financial resources, Swaziland is likely to achieve 100% coverage of both water supply and sanitation by the year 2022. It was concluded that in achieving its own national goals Swaziland will exceed the Millennium Development Goals (MDGs). However, such achievement is subject to adequate financial resources being made available for the RWSS sector.
Health Reform and Utilization of High-Volume Hospitals for Complex Cancer Operations.

PubMed

Loehrer, Andrew P; Chang, David C; Song, Zirui; Chang, George J

2018-01-01

Underinsured patients are less likely to receive complex cancer operations at hospitals with high surgical volumes (high-volume hospitals, or HVHs), which contributes to disparities in care. To date, the impact of insurance coverage expansion on site of complex cancer surgery remains unknown. Using the 2006 Massachusetts coverage expansion as a natural experiment, we searched the Hospital Cost and Utilization Project state inpatient databases for Massachusetts and control states (New York, New Jersey, and Florida) between 2001 and 2011 to evaluate changes in the utilization of HVHs for resections of bladder, esophageal, stomach, pancreatic, rectal, or lung cancer after the expansion of insurance coverage. We studied nonelderly, adult patients with private insurance and those with government-subsidized or self-pay (GSSP) coverage with a difference-in-differences framework. We studied 11,687 patients in Massachusetts and 56,300 patients in control states. Compared with control states, the 2006 Massachusetts insurance expansion was associated with a 14% increased rate of surgical intervention for GSSP patients (incident rate ratio, 1.14; P = .015), but there was no significant change in the probability of GSSP patients undergoing surgery at an HVH (1.0 percentage-point increase; P = .710). The reform was associated with no change in the uninsured payer-mix at HVHs (0.6 percentage-point increase; P = .244) and with a 5.1 percentage-point decrease for the uninsured payer mix at low-volume hospitals ( P < .001). The 2006 Massachusetts insurance expansion, a model for the Affordable Care Act, was associated with increased rates of complex cancer operations and increased insurance coverage but with no change in utilization of HVH for complex cancer operations.
Cost-Utility Analysis of Extending Public Health Insurance Coverage to Include Diabetic Retinopathy Screening by Optometrists.

PubMed

van Katwyk, Sasha; Jin, Ya-Ping; Trope, Graham E; Buys, Yvonne; Masucci, Lisa; Wedge, Richard; Flanagan, John; Brent, Michael H; El-Defrawy, Sherif; Tu, Hong Anh; Thavorn, Kednapa

2017-09-01

Diabetic retinopathy (DR) is one of the leading causes of vision loss and blindness in Canada. Eye examinations play an important role in early detection. However, DR screening by optometrists is not always universally covered by public or private health insurance plans. This study assessed whether expanding public health coverage to include diabetic eye examinations for retinopathy by optometrists is cost-effective from the perspective of the health care system. We conducted a cost-utility analysis of extended coverage for diabetic eye examinations in Prince Edward Island to include examinations by optometrists, not currently publicly covered. We used a Markov chain to simulate disease burden based on eye examination rates and DR progression over a 30-year time horizon. Results were presented as an incremental cost per quality-adjusted life year (QALY) gained. A series of one-way and probabilistic sensitivity analyses were performed. Extending public health coverage to eye examinations by optometrists was associated with higher costs ($9,908,543.32) and improved QALYs (156,862.44), over 30 years, resulting in an incremental cost-effectiveness ratio of $1668.43/QALY gained. Sensitivity analysis showed that the most influential determinants of the results were the cost of optometric screening and selected utility scores. At the commonly used threshold of $50,000/QALY, the probability that the new policy was cost-effective was 99.99%. Extending public health coverage to eye examinations by optometrists is cost-effective based on a commonly used threshold of $50,000/QALY. Findings from this study can inform the decision to expand public-insured optometric services for patients with diabetes. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
Prevalence and treatment coverage for depression: a population-based survey in Vidarbha, India.

PubMed

Shidhaye, Rahul; Gangale, Siddharth; Patel, Vikram

2016-07-01

VISHRAM is a community-based mental health program to address psycho-social distress and risk factors for suicide in a predominantly rural population in Central India, through targeted interventions for the prevention and management of Depression and Alcohol Use Disorders (AUD). The evaluation was designed to assess the impact of program on the contact coverage of evidence-based treatments for depression and AUD through a repeated survey design. This paper describes the baseline prevalence of depression among adults in rural community, association of various demographic and socio-economic factors with depression and estimates contact coverage and costs of care for depression. Population-based cross-sectional survey of adults in 30 villages of Amravati district in Vidarbha region of Central India. The outcome of interest was a probable diagnosis of depression which was measured using the Patient Health Questionnaire (PHQ-9). Data were analyzed using simple and multiple logistic regression. The outcome of current depression (PHQ-9 ≥ 10) was observed in 14.6 % of the sample (95 % CI 12.8-16.4 %). The contact coverage for current depression was only 4.3 % (95 % CI 1.5-7.1 %). Prevalence of depression varied greatly between the two sites of the study; higher age, female gender, lower education, economic status below poverty line and indebtedness were associated with depression; and while a contact coverage with formal health care was very low, a large proportion of affected persons had consulted family members. Our findings clearly indicate that psycho-social distress in rural communities in Maharashtra is strongly associated with social determinants such as gender, poverty and indebtedness and affects the entire population and not just farmers.
ARACNe-AP: Gene Network Reverse Engineering through Adaptive Partitioning inference of Mutual Information. | Office of Cancer Genomics

Cancer.gov

The accurate reconstruction of gene regulatory networks from large scale molecular profile datasets represents one of the grand challenges of Systems Biology. The Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) represents one of the most effective tools to accomplish this goal. However, the initial Fixed Bandwidth (FB) implementation is both inefficient and unable to deal with sample sets providing largely uneven coverage of the probability density space.
Develop Measures of Effectiveness and Deployment Optimization Rules for Networked Ground Micro-Sensors

DTIC Science & Technology

2001-05-01

types and total #) Ø Control of Sensors ( Scheduling ) Ø Coverage (Time & Area) Uncontrollable Inputs ØWeather Ø Atmospheric Effects Ø Equipment...are widely scattered and used to cue or wakeup other higher-level sensors. Trip line sensors consist of some combination of acoustic, seismic and...Employ a mix if different sensor types in order to increase detection probability 4.4.4.2 Minimize Battery Power • Set schedule turn on and off
On land-use modeling: A treatise of satellite imagery data and misclassification error

NASA Astrophysics Data System (ADS)

Sandler, Austin M.

Recent availability of satellite-based land-use data sets, including data sets with contiguous spatial coverage over large areas, relatively long temporal coverage, and fine-scale land cover classifications, is providing new opportunities for land-use research. However, care must be used when working with these datasets due to misclassification error, which causes inconsistent parameter estimates in the discrete choice models typically used to model land-use. I therefore adapt the empirical correction methods developed for other contexts (e.g., epidemiology) so that they can be applied to land-use modeling. I then use a Monte Carlo simulation, and an empirical application using actual satellite imagery data from the Northern Great Plains, to compare the results of a traditional model ignoring misclassification to those from models accounting for misclassification. Results from both the simulation and application indicate that ignoring misclassification will lead to biased results. Even seemingly insignificant levels of misclassification error (e.g., 1%) result in biased parameter estimates, which alter marginal effects enough to affect policy inference. At the levels of misclassification typical in current satellite imagery datasets (e.g., as high as 35%), ignoring misclassification can lead to systematically erroneous land-use probabilities and substantially biased marginal effects. The correction methods I propose, however, generate consistent parameter estimates and therefore consistent estimates of marginal effects and predicted land-use probabilities.
Inequalities in child immunization coverage in Ghana: evidence from a decomposition analysis.

PubMed

Asuman, Derek; Ackah, Charles Godfred; Enemark, Ulrika

2018-04-11

Childhood vaccination has been promoted as a global intervention aimed at improving child survival and health, through the reduction of vaccine preventable deaths. However, there exist significant inequalities in achieving universal coverage of child vaccination among and within countries. In this paper, we examine rural-urban inequalities in child immunizations in Ghana. Using data from the recent two waves of the Ghana Demographic and Health Survey, we examine the probability that a child between 12 and 59 months receives the required vaccinations and proceed to decompose the sources of inequalities in the probability of full immunization between rural and urban areas. We find significant child-specific, maternal and household characteristics on a child's immunization status. The results show that children in rural areas are more likely to complete the required vaccinations. The direction and sources of inequalities in child immunizations have changed between the two survey waves. We find a pro-urban advantage in 2008 arising from differences in observed characteristics whilst a pro-rural advantage emerges in 2014 dominated by the differences in coefficients. Health system development and campaign efforts have focused on rural areas. There is a need to also specifically target vulnerable children in urban areas, to maintain focus on women empowerment and pay attention to children from high socio-economic households in less favourable economic times.
Bladder radiotherapy treatment: A retrospective comparison of 3-dimensional conformal radiotherapy, intensity-modulated radiation therapy, and volumetric-modulated arc therapy plans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasciuti, Katia, E-mail: k.pasciuti@virgilio.it; Kuthpady, Shrinivas; Anderson, Anne

To examine tumor's and organ's response when different radiotherapy plan techniques are used. Ten patients with confirmed bladder tumors were first treated using 3-dimensional conformal radiotherapy (3DCRT) and subsequently the original plans were re-optimized using the intensity-modulated radiation treatment (IMRT) and volumetric-modulated arc therapy (VMAT)-techniques. Targets coverage in terms of conformity and homogeneity index, TCP, and organs' dose limits, including integral dose analysis were evaluated. In addition, MUs and treatment delivery times were compared. Better minimum target coverage (1.3%) was observed in VMAT plans when compared to 3DCRT and IMRT ones confirmed by a statistically significant conformity index (CI) results.more » Large differences were observed among techniques in integral dose results of the femoral heads. Even if no statistically significant differences were reported in rectum and tissue, a large amount of energy deposition was observed in 3DCRT plans. In any case, VMAT plans provided better organs and tissue sparing confirmed also by the normal tissue complication probability (NTCP) analysis as well as a better tumor control probability (TCP) result. Our analysis showed better overall results in planning using VMAT techniques. Furthermore, a total time reduction in treatment observed among techniques including gantry and collimator rotation could encourage using the more recent one, reducing target movements and patient discomfort.« less
45 CFR 1801.18 - Limitations on nominations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 4 2014-10-01 2014-10-01 false Limitations on nominations. 1801.18 Section 1801.18 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.18 Limitations on nominations. A candidate...
45 CFR 1801.18 - Limitations on nominations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 4 2011-10-01 2011-10-01 false Limitations on nominations. 1801.18 Section 1801.18 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.18 Limitations on nominations. A candidate...
45 CFR 1801.18 - Limitations on nominations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Limitations on nominations. 1801.18 Section 1801.18 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.18 Limitations on nominations. A candidate...

45 CFR 1801.18 - Limitations on nominations.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 4 2012-10-01 2012-10-01 false Limitations on nominations. 1801.18 Section 1801.18 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.18 Limitations on nominations. A candidate...
45 CFR 1801.18 - Limitations on nominations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 4 2013-10-01 2013-10-01 false Limitations on nominations. 1801.18 Section 1801.18 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.18 Limitations on nominations. A candidate...
7 CFR 1220.203 - Nominations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... CONSUMER INFORMATION Soybean Promotion and Research Order United Soybean Board § 1220.203 Nominations. All... be filled. (e) Nominations may be submitted in order of preference and for the initial Board, in order of preference for staggered terms. Should the Secretary reject any nomination submitted and there...
7 CFR 932.31 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 932.31 Section 932.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Olive Administrative Committee § 932.31 Failure to nominate. If nominations for any...
7 CFR 953.20 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Failure to nominate. 953.20 Section 953.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... STATES Order Regulating Handling Administrative Committee § 953.20 Failure to nominate. If nominations...
7 CFR 953.20 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 953.20 Section 953.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... STATES Order Regulating Handling Administrative Committee § 953.20 Failure to nominate. If nominations...
7 CFR 932.31 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Failure to nominate. 932.31 Section 932.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Regulating Handling Olive Administrative Committee § 932.31 Failure to nominate. If nominations for any...
7 CFR 927.25 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Failure to nominate. 927.25 Section 927.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Administrative Bodies § 927.25 Failure to nominate. In the event nominations...
7 CFR 932.31 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Failure to nominate. 932.31 Section 932.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Olive Administrative Committee § 932.31 Failure to nominate. If nominations for any...
7 CFR 953.20 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 953.20 Section 953.20 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... STATES Order Regulating Handling Administrative Committee § 953.20 Failure to nominate. If nominations...
7 CFR 917.26 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Failure to nominate. 917.26 Section 917.26 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... CALIFORNIA Order Regulating Handling Administrative Bodies § 917.26 Failure to nominate. If nominations are...
7 CFR 927.25 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 927.25 Section 927.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Administrative Bodies § 927.25 Failure to nominate. In the event nominations...
7 CFR 917.26 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Failure to nominate. 917.26 Section 917.26 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... CALIFORNIA Order Regulating Handling Administrative Bodies § 917.26 Failure to nominate. If nominations are...
7 CFR 927.25 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 927.25 Section 927.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Administrative Bodies § 927.25 Failure to nominate. In the event nominations...
7 CFR 917.26 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Failure to nominate. 917.26 Section 917.26 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... CALIFORNIA Order Regulating Handling Administrative Bodies § 917.26 Failure to nominate. If nominations are...
7 CFR 917.26 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 917.26 Section 917.26 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... CALIFORNIA Order Regulating Handling Administrative Bodies § 917.26 Failure to nominate. If nominations are...
7 CFR 932.31 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 932.31 Section 932.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Olive Administrative Committee § 932.31 Failure to nominate. If nominations for any...
7 CFR 917.26 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 917.26 Section 917.26 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... CALIFORNIA Order Regulating Handling Administrative Bodies § 917.26 Failure to nominate. If nominations are...
7 CFR 932.31 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Failure to nominate. 932.31 Section 932.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Regulating Handling Olive Administrative Committee § 932.31 Failure to nominate. If nominations for any...
7 CFR 927.25 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Failure to nominate. 927.25 Section 927.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Order Regulating Handling Administrative Bodies § 927.25 Failure to nominate. In the event nominations...

7 CFR 927.25 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Failure to nominate. 927.25 Section 927.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Order Regulating Handling Administrative Bodies § 927.25 Failure to nominate. In the event nominations...
Lot quality assurance sampling for monitoring immunization programmes: cost-efficient or quick and dirty?

PubMed

Sandiford, P

1993-09-01

In recent years Lot quality assurance sampling (LQAS), a method derived from production-line industry, has been advocated as an efficient means to evaluate the coverage rates achieved by child immunization programmes. This paper examines the assumptions on which LQAS is based and the effect that these assumptions have on its utility as a management tool. It shows that the attractively low sample sizes used in LQAS are achieved at the expense of specificity unless unrealistic assumptions are made about the distribution of coverage rates amongst the immunization programmes to which the method is applied. Although it is a very sensitive test and its negative predictive value is probably high in most settings, its specificity and positive predictive value are likely to be low. The implications of these strengths and weaknesses with regard to management decision-making are discussed.
A new single-photon avalanche diode in 90nm standard CMOS technology.

PubMed

Karami, Mohammad Azim; Gersbach, Marek; Yoon, Hyung-June; Charbon, Edoardo

2010-10-11

We report on the first implementation of a single-photon avalanche diode (SPAD) in 90nm complementary metal oxide semiconductor (CMOS) technology. The detector features an octagonal multiplication region and a guard ring to prevent premature edge breakdown using a standard mask set exclusively. The proposed structure emerged from a systematic study aimed at miniaturization, while optimizing overall performance. The guard ring design is the result of an extensive modeling effort aimed at constraining the multiplication region within a well-defined area where the electric field exceeds the critical value for impact ionization. The device exhibits a dark count rate of 8.1 kHz, a maximum photon detection probability of 9% and the jitter of 398ps at a wavelength of 637nm, all of them measured at room temperature and 0.13V of excess bias voltage. An afterpulsing probability of 32% is achieved at the nominal dead time. Applications include time-of-flight 3D vision, fluorescence lifetime imaging microscopy, fluorescence correlation spectroscopy, and time-resolved gamma/X-ray imaging. Standard characterization of the SPAD was performed in different bias voltages and temperatures.
Empirical assessment of published effect sizes and power in the recent cognitive neuroscience and psychology literature

PubMed Central

Szucs, Denes; Ioannidis, John P. A.

2017-01-01

We have empirically assessed the distribution of published effect sizes and estimated power by analyzing 26,841 statistical records from 3,801 cognitive neuroscience and psychology papers published recently. The reported median effect size was D = 0.93 (interquartile range: 0.64–1.46) for nominally statistically significant results and D = 0.24 (0.11–0.42) for nonsignificant results. Median power to detect small, medium, and large effects was 0.12, 0.44, and 0.73, reflecting no improvement through the past half-century. This is so because sample sizes have remained small. Assuming similar true effect sizes in both disciplines, power was lower in cognitive neuroscience than in psychology. Journal impact factors negatively correlated with power. Assuming a realistic range of prior probabilities for null hypotheses, false report probability is likely to exceed 50% for the whole literature. In light of our findings, the recently reported low replication success in psychology is realistic, and worse performance may be expected for cognitive neuroscience. PMID:28253258
Reliability of Radioisotope Stirling Convertor Linear Alternator

NASA Technical Reports Server (NTRS)

Shah, Ashwin; Korovaichuk, Igor; Geng, Steven M.; Schreiber, Jeffrey G.

2006-01-01

Onboard radioisotope power systems being developed and planned for NASA s deep-space missions would require reliable design lifetimes of up to 14 years. Critical components and materials of Stirling convertors have been undergoing extensive testing and evaluation in support of a reliable performance for the specified life span. Of significant importance to the successful development of the Stirling convertor is the design of a lightweight and highly efficient linear alternator. Alternator performance could vary due to small deviations in the permanent magnet properties, operating temperature, and component geometries. Durability prediction and reliability of the alternator may be affected by these deviations from nominal design conditions. Therefore, it is important to evaluate the effect of these uncertainties in predicting the reliability of the linear alternator performance. This paper presents a study in which a reliability-based methodology is used to assess alternator performance. The response surface characterizing the induced open-circuit voltage performance is constructed using 3-D finite element magnetic analysis. Fast probability integration method is used to determine the probability of the desired performance and its sensitivity to the alternator design parameters.
When epilepsy may have changed history: Antônio Moreira César as the commander of the third expedition in the war of Canudos.

PubMed

Yacubian, Elza Márcia Targas

2003-06-01

Colonel Antônio Moreira César, the Commander of the third Expedition against Canudos (1896-1897), nicknamed "head-chopper", was considered an implacable military man, a synonym of ferocity and extreme brutality against his adversaries. Therefore, he was nominated the Commander of an expedition considered almost invincible. Since his 30's he presented epileptic seizures, which increased in frequency and severity on his way to Canudos. After several well-documented episodes and probably considering himself the winner in anticipation, he ordered a premature and almost ingenuous attack against Canudos. His misjudging is attributed to the effect of successive seizures. He was shot and killed on the very first day of that battle and his expedition had a horrible and unexpected end. Based on the descriptions of his biographer we discuss the nature of his disease probably characterized by focal seizures with elementary and complex visual hallucinations followed by language deficits and episodes of complex partial seizures and secondary generalization and its role in this episode of Brazilian history.
75 FR 44793 - Consumer Advisory Council Solicitation of Nominations for Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-29

... to nominate qualified individuals for appointment to its Consumer Advisory Council, whose membership... affiliation, title, address, phone and fax numbers, and e-mail address. Individuals may nominate themselves... does not limit consideration to individuals nominated by the public when making its selection. Council...
36 CFR 60.11 - Requests for nominations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and appears to meet the National Register criteria for evaluation in § 60.4. If the nomination form is... any person or organization submitting a completed National Register nomination form or requesting consideration for any previously prepared nomination form on record with the State or Federal agency. The...
7 CFR 1219.34 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 10 2012-01-01 2012-01-01 false Failure to nominate. 1219.34 Section 1219.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING....34 Failure to nominate. In any case in which producers or importers fail to nominate individuals for...
7 CFR 915.24 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Failure to nominate. 915.24 Section 915.24 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Regulating Handling Administrative Body § 915.24 Failure to nominate. If nominations are not made within the...
7 CFR 915.24 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Failure to nominate. 915.24 Section 915.24 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Administrative Body § 915.24 Failure to nominate. If nominations are not made within the...
7 CFR 1219.34 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 10 2013-01-01 2013-01-01 false Failure to nominate. 1219.34 Section 1219.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING....34 Failure to nominate. In any case in which producers or importers fail to nominate individuals for...
7 CFR 915.24 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Failure to nominate. 915.24 Section 915.24 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Regulating Handling Administrative Body § 915.24 Failure to nominate. If nominations are not made within the...
7 CFR 948.57 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 8 2014-01-01 2014-01-01 false Failure to nominate. 948.57 Section 948.57 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Order Regulating Handling Committees § 948.57 Failure to nominate. If nominations are not made pursuant...
7 CFR 948.57 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Failure to nominate. 948.57 Section 948.57 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Order Regulating Handling Committees § 948.57 Failure to nominate. If nominations are not made pursuant...
7 CFR 948.57 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 948.57 Section 948.57 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Committees § 948.57 Failure to nominate. If nominations are not made pursuant...
7 CFR 1219.34 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 10 2011-01-01 2011-01-01 false Failure to nominate. 1219.34 Section 1219.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING....34 Failure to nominate. In any case in which producers or importers fail to nominate individuals for...
7 CFR 916.24 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Failure to nominate. 916.24 Section 916.24 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Administrative Body § 916.24 Failure to nominate. If nominations are not made within the...
7 CFR 916.24 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 916.24 Section 916.24 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Administrative Body § 916.24 Failure to nominate. If nominations are not made within the...
7 CFR 948.57 - Failure to nominate.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Failure to nominate. 948.57 Section 948.57 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Committees § 948.57 Failure to nominate. If nominations are not made pursuant...

7 CFR 948.57 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 948.57 Section 948.57 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Order Regulating Handling Committees § 948.57 Failure to nominate. If nominations are not made pursuant...
7 CFR 1219.34 - Failure to nominate.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 10 2014-01-01 2014-01-01 false Failure to nominate. 1219.34 Section 1219.34 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING....34 Failure to nominate. In any case in which producers or importers fail to nominate individuals for...
7 CFR 915.24 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 915.24 Section 915.24 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Administrative Body § 915.24 Failure to nominate. If nominations are not made within the...
Use of a Teacher Nomination Strategy to Screen for Autism Spectrum Disorders in General Education Classrooms: A Pilot Study

PubMed Central

Hepburn, Susan L.; DiGuiseppi, Carolyn; Rosenberg, Steven; Kaparich, Kristina; Robinson, Cordelia; Miller, Lisa

2015-01-01

Given a rising prevalence of autism spectrum disorders (ASD), this project aimed to develop and pilot test various teacher nomination strategies to identify children at risk for ASD in a timely, reliable, cost-effective manner. Sixty participating elementary school teachers evaluated 1323 children in total. Each teacher nominated students who most fit a description of ASD-associated characteristics, and completed the Autism Syndrome Screening Questionnaire (ASSQ) on every child in the classroom. The proportion of overall agreement between teacher nomination and ASSQ was 93–95%, depending upon the nomination parameters. Nomination required 15 min per class versus 3.5–5.5 h per class for the ASSQ. These results support the need for further study of teacher nomination strategies to identify children at risk for ASD. PMID:17661165
Shuttle STS-2 mission communication systems RF coverage and performance predictions. Volume 1: Ascent

NASA Technical Reports Server (NTRS)

Porter, J. A.; Gibson, J. S.; Kroll, Q. D.; Loh, Y. C.

1981-01-01

The RF communications capabilities and nominally expected performance for the ascent phase of the second orbital flight of the shuttle are provided. Predicted performance is given mainly in the form of plots of signal strength versus elapsed mission time for the STDN (downlink) and shuttle orbiter (uplink) receivers for the S-band PM and FM, and UHF systems. Performance of the NAV and landing RF systems is treated for RTLS abort, since in this case the spacecraft will loop around and return to the launch site. NAV and landing RF systems include TACAN, MSBLS, and C-band altimeter. Signal strength plots were produced by a computer program which combines the spacecraft trajectory, antenna patterns, transmit and receive performance characteristics, and system mathematical models. When available, measured spacecraft parameters were used in the predictions; otherwise, specified values were used. Specified ground station parameter values were also used. Thresholds and other criteria on the graphs are explained.
Construction of a 3-arcsecond digital elevation model for the Gulf of Maine

USGS Publications Warehouse

Twomey, Erin R.; Signell, Richard P.

2013-01-01

A system-wide description of the seafloor topography is a basic requirement for most coastal oceanographic studies. The necessary detail of the topography obviously varies with application, but for many uses, a nominal resolution of roughly 100 m is sufficient. Creating a digital bathymetric grid with this level of resolution can be a complex procedure due to a multiplicity of data sources, data coverages, datums and interpolation procedures. This report documents the procedures used to construct a 3-arcsecond (approximately 90-meter grid cell size) digital elevation model for the Gulf of Maine (71°30' to 63° W, 39°30' to 46° N). We obtained elevation and bathymetric data from a variety of American and Canadian sources, converted all data to the North American Datum of 1983 for horizontal coordinates and the North American Vertical Datum of 1988 for vertical coordinates, used a combination of automatic and manual techniques for quality control, and interpolated gaps using a surface-fitting routine.
Surface roughness effects on the solar reflectance of cool asphalt shingles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akbari, Hashem; Berdahl, Paul; Akbari, Hashem

2008-02-17

We analyze the solar reflectance of asphalt roofing shingles that are covered with pigmented mineral roofing granules. The reflecting surface is rough, with a total area approximately twice the nominal area. We introduce a simple analytical model that relates the 'micro-reflectance' of a small surface region to the 'macro-reflectance' of the shingle. This model uses a mean field approximation to account for multiple scattering effects. The model is then used to compute the reflectance of shingles with a mixture of different colored granules, when the reflectances of the corresponding mono-color shingles are known. Simple linear averaging works well, with smallmore » corrections to linear averaging derived for highly reflective materials. Reflective base granules and reflective surface coatings aid achievement of high solar reflectance. Other factors that influence the solar reflectance are the size distribution of the granules, coverage of the asphalt substrate, and orientation of the granules as affected by rollers during fabrication.« less
Petite Amateur Navy Satellite (PANSAT)

NASA Technical Reports Server (NTRS)

1989-01-01

The subsystem and structural design of the Naval Post Graduate School's Petite Amateur Navy Satellite (PANSAT) is described. The objectives of PANSAT are: (1) to provide an ideal educational tool for officer students; (2) to provide digital store-and-forward communications, or packet radio, for the amateur radio community; and (3) to provide a low-cost space-based platform for small experiments. PANSAT will be launched from the Shuttle at a nominal altitude of 200 nmi. and an inclination of at least 37 deg. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 144 to 146 MHz or 437 to 438 MHz. The satellite's communications subsystem, data processor and sequencer, power subsystem, structure subsystem, and experiment payload are described. The major experiment being considered will test the on-orbit annealing of radiation damaged solar cells.
[Fund for Protection against Catastrophic Expenses].

PubMed

Aracena-Genao, Belkis; González-Robledo, María Cecilia; González-Robledo, Luz María; Palacio-Mejía, Lina Sofía; Nigenda-López, Gustavo

2011-01-01

To document the status of operational and managerial processes of the Fund for Protection against Catastrophic Expenses (FPGC), as well as to describe its evolution, and to explore the relationship between covered diseases and the Mexican health profile. This is a joint management study, which included a qualitative and a quantitative phase. We conducted semi-structured interviews with key informants. We also analyzed the records of CNPSS, the hospital discharge and mortality data bases. Fifty two percent of the states take twice as long to report and validate the cases. From 2004-2009 the FPGC increased its coverage from 6 to 49 interventions, that means a spending increase of 2 306.4% in nominal terms and 1 659.3% in real terms. The HIV/AIDS was the intervention prioritized with 39.3% and Mexico City had the highest proportion of expenditure (25.1%). A few diseases included in the health profile are covered by the FPGC. The review of the inclusion criteria of diseases is urgent, so as to cover diseases of epidemiological importance.
Forecasting Tehran stock exchange volatility; Markov switching GARCH approach

NASA Astrophysics Data System (ADS)

Abounoori, Esmaiel; Elmi, Zahra (Mila); Nademi, Younes

2016-03-01

This paper evaluates several GARCH models regarding their ability to forecast volatility in Tehran Stock Exchange (TSE). These include GARCH models with both Gaussian and fat-tailed residual conditional distribution, concerning their ability to describe and forecast volatility from 1-day to 22-day horizon. Results indicate that AR(2)-MRSGARCH-GED model outperforms other models at one-day horizon. Also, the AR(2)-MRSGARCH-GED as well as AR(2)-MRSGARCH-t models outperform other models at 5-day horizon. In 10 day horizon, three models of AR(2)-MRSGARCH outperform other models. Concerning 22 day forecast horizon, results indicate no differences between MRSGARCH models with that of standard GARCH models. Regarding Risk management out-of-sample evaluation (95% VaR), a few models seem to provide reasonable and accurate VaR estimates at 1-day horizon, with a coverage rate close to the nominal level. According to the risk management loss functions, there is not a uniformly most accurate model.
Bayesian inference and assessment for rare-event bycatch in marine fisheries: a drift gillnet fishery case study.

PubMed

Martin, Summer L; Stohs, Stephen M; Moore, Jeffrey E

2015-03-01

Fisheries bycatch is a global threat to marine megafauna. Environmental laws require bycatch assessment for protected species, but this is difficult when bycatch is rare. Low bycatch rates, combined with low observer coverage, may lead to biased, imprecise estimates when using standard ratio estimators. Bayesian model-based approaches incorporate uncertainty, produce less volatile estimates, and enable probabilistic evaluation of estimates relative to management thresholds. Here, we demonstrate a pragmatic decision-making process that uses Bayesian model-based inferences to estimate the probability of exceeding management thresholds for bycatch in fisheries with < 100% observer coverage. Using the California drift gillnet fishery as a case study, we (1) model rates of rare-event bycatch and mortality using Bayesian Markov chain Monte Carlo estimation methods and 20 years of observer data; (2) predict unobserved counts of bycatch and mortality; (3) infer expected annual mortality; (4) determine probabilities of mortality exceeding regulatory thresholds; and (5) classify the fishery as having low, medium, or high bycatch impact using those probabilities. We focused on leatherback sea turtles (Dermochelys coriacea) and humpback whales (Megaptera novaeangliae). Candidate models included Poisson or zero-inflated Poisson likelihood, fishing effort, and a bycatch rate that varied with area, time, or regulatory regime. Regulatory regime had the strongest effect on leatherback bycatch, with the highest levels occurring prior to a regulatory change. Area had the strongest effect on humpback bycatch. Cumulative bycatch estimates for the 20-year period were 104-242 leatherbacks (52-153 deaths) and 6-50 humpbacks (0-21 deaths). The probability of exceeding a regulatory threshold under the U.S. Marine Mammal Protection Act (Potential Biological Removal, PBR) of 0.113 humpback deaths was 0.58, warranting a "medium bycatch impact" classification of the fishery. No PBR thresholds exist for leatherbacks, but the probability of exceeding an anticipated level of two deaths per year, stated as part of a U.S. Endangered Species Act assessment process, was 0.0007. The approach demonstrated here would allow managers to objectively and probabilistically classify fisheries with respect to bycatch impacts on species that have population-relevant mortality reference points, and declare with a stipulated level of certainty that bycatch did or did not exceed estimated upper bounds.
24 CFR 598.205 - What are the requirements for nomination?

Code of Federal Regulations, 2013 CFR

2013-04-01

... nomination? 598.205 Section 598.205 Housing and Urban Development Regulations Relating to Housing and Urban... DESIGNATIONS Nomination Procedure § 598.205 What are the requirements for nomination? (a) General. No urban... that the strategic plan described in § 598.215 will be implemented, and these governments submit its...
24 CFR 598.205 - What are the requirements for nomination?

Code of Federal Regulations, 2012 CFR

2012-04-01

... nomination? 598.205 Section 598.205 Housing and Urban Development Regulations Relating to Housing and Urban... DESIGNATIONS Nomination Procedure § 598.205 What are the requirements for nomination? (a) General. No urban... that the strategic plan described in § 598.215 will be implemented, and these governments submit its...
24 CFR 598.205 - What are the requirements for nomination?

Code of Federal Regulations, 2014 CFR

2014-04-01

... nomination? 598.205 Section 598.205 Housing and Urban Development Regulations Relating to Housing and Urban... DESIGNATIONS Nomination Procedure § 598.205 What are the requirements for nomination? (a) General. No urban... that the strategic plan described in § 598.215 will be implemented, and these governments submit its...
76 FR 71566 - Solicitation of Nominations for Membership on the National Vaccine Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-18

...., Public Health Advisor, National Vaccine Program Office, Department of Health and Human Services, 200... vacated during the calendar year 2012. Nominations In accordance with the charter, persons nominated for... information should be included in the package of material submitted for each individual being nominated for...
78 FR 31939 - Solicitation of Nominations for Membership on the National Vaccine Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-28

...., Public Health Advisor, National Vaccine Program Office, Department of Health and Human Services, 200... vacated during the calendar year 2013. Nominations In accordance with the charter, persons nominated for... information should be included in the package of material submitted for each individual being nominated for...
7 CFR 25.502 - Nominations by State-chartered economic development corporations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 1 2010-01-01 2010-01-01 false Nominations by State-chartered economic development... AND ENTERPRISE COMMUNITIES Special Rules § 25.502 Nominations by State-chartered economic development corporations. Any rural area nominated by an economic development corporation chartered by a State and...
75 FR 28782 - Extension of Period for Nominations to the National Medal of Technology and Innovation Nomination...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-24

... innovation and/or be familiar with the education, training, employment and management of technological... Innovations/Bioengineering and Biomedical Technology; Technology Management/Computing/IT/Manufacturing...] Extension of Period for Nominations to the National Medal of Technology and Innovation Nomination Evaluation...
Exploring Reference Group Effects on Teachers' Nominations of Gifted Students

ERIC Educational Resources Information Center

Rothenbusch, Sandra; Zettler, Ingo; Voss, Thamar; Lösch, Thomas; Trautwein, Ulrich

2016-01-01

Teachers are often asked to nominate students for enrichment programs for gifted children, and studies have repeatedly indicated that students' intelligence is related to their likelihood of being nominated as gifted. However, it is unknown whether class-average levels of intelligence influence teachers' nominations as suggested by theory--and…
Trajectories of Peer-Nominated Aggression: Risk Status, Predictors and Outcomes.

ERIC Educational Resources Information Center

van Lier, Pol A.C.; Crijnen, Alfons A.M.

2005-01-01

Developmental trajectories of peer-nominated aggression, risk factors at baseline, and outcomes were studied. Peer nominations of aggression were obtained annually from grades 1 to 3. Three developmental trajectories were identified: an early-onset/increasers trajectory with high levels of peer-nominated aggression at elementary school entry and…

36 CFR 60.10 - Concurrent State and Federal nominations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... cultural value. Federal agencies may nominate properties where a portion of the property is not under Federal ownership or control. (b) When a portion of the area included in a Federal nomination is not... cultural resource, the completed nomination form shall be sent to the State Historic Preservation Officer...
45 CFR 1801.10 - Nomination by institution of higher education.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 4 2013-10-01 2013-10-01 false Nomination by institution of higher education. 1801.10 Section 1801.10 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.10 Nomination by...
45 CFR 1801.11 - Annual nomination.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 4 2011-10-01 2011-10-01 false Annual nomination. 1801.11 Section 1801.11 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.11 Annual nomination. (a) Except as provided in §§ 1801.11...
45 CFR 1801.11 - Annual nomination.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 4 2014-10-01 2014-10-01 false Annual nomination. 1801.11 Section 1801.11 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.11 Annual nomination. (a) Except as provided in §§ 1801.11...
45 CFR 1801.11 - Annual nomination.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 45 Public Welfare 4 2013-10-01 2013-10-01 false Annual nomination. 1801.11 Section 1801.11 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.11 Annual nomination. (a) Except as provided in §§ 1801.11...
45 CFR 1801.10 - Nomination by institution of higher education.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 4 2011-10-01 2011-10-01 false Nomination by institution of higher education. 1801.10 Section 1801.10 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.10 Nomination by...
45 CFR 1801.10 - Nomination by institution of higher education.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 45 Public Welfare 4 2014-10-01 2014-10-01 false Nomination by institution of higher education. 1801.10 Section 1801.10 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.10 Nomination by...
45 CFR 1801.11 - Annual nomination.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Annual nomination. 1801.11 Section 1801.11 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.11 Annual nomination. (a) Except as provided in §§ 1801.11...
45 CFR 1801.11 - Annual nomination.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 4 2012-10-01 2012-10-01 false Annual nomination. 1801.11 Section 1801.11 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.11 Annual nomination. (a) Except as provided in §§ 1801.11...
45 CFR 1801.10 - Nomination by institution of higher education.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 45 Public Welfare 4 2012-10-01 2012-10-01 false Nomination by institution of higher education. 1801.10 Section 1801.10 Public Welfare Regulations Relating to Public Welfare (Continued) HARRY S. TRUMAN SCHOLARSHIP FOUNDATION HARRY S. TRUMAN SCHOLARSHIP PROGRAM Nominations § 1801.10 Nomination by...
7 CFR 25.502 - Nominations by State-chartered economic development corporations.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 1 2013-01-01 2013-01-01 false Nominations by State-chartered economic development... AND ENTERPRISE COMMUNITIES Special Rules § 25.502 Nominations by State-chartered economic development corporations. Any rural area nominated by an economic development corporation chartered by a State and...
7 CFR 25.502 - Nominations by State-chartered economic development corporations.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 1 2014-01-01 2014-01-01 false Nominations by State-chartered economic development... AND ENTERPRISE COMMUNITIES Special Rules § 25.502 Nominations by State-chartered economic development corporations. Any rural area nominated by an economic development corporation chartered by a State and...
7 CFR 25.502 - Nominations by State-chartered economic development corporations.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 1 2011-01-01 2011-01-01 false Nominations by State-chartered economic development... AND ENTERPRISE COMMUNITIES Special Rules § 25.502 Nominations by State-chartered economic development corporations. Any rural area nominated by an economic development corporation chartered by a State and...
7 CFR 25.502 - Nominations by State-chartered economic development corporations.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 1 2012-01-01 2012-01-01 false Nominations by State-chartered economic development... AND ENTERPRISE COMMUNITIES Special Rules § 25.502 Nominations by State-chartered economic development corporations. Any rural area nominated by an economic development corporation chartered by a State and...
77 FR 48168 - Call for Nominations for the Twin Falls District Resource Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-13

... for Nominations for the Twin Falls District Resource Advisory Council AGENCY: Bureau of Land Management, Interior. ACTION: Call for Nominations, Twin Falls District Resource Advisory Council SUMMARY: This notice requests public nominations to fill one position on the Twin Falls District Resource...
75 FR 69631 - National Medal of Technology and Innovation Nomination Evaluation Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-15

... selection. NMTI Nomination Evaluation Committee members are drawn from both the public and private sectors... Technology and Innovation Nomination Evaluation Committee Meeting AGENCY: United States Patent and Trademark... Innovation (NMTI) Nomination Evaluation Committee will meet in closed session on Tuesday, November 30, 2010...
7 CFR 930.25 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 930.25 Section 930.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Administrative Body § 930.25 Failure to nominate. If nominations are not made within the time and in the manner...
7 CFR 959.28 - Failure to nominate.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 8 2012-01-01 2012-01-01 false Failure to nominate. 959.28 Section 959.28 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Committee § 959.28 Failure to nominate. If nominations are not made within the time and...
7 CFR 959.28 - Failure to nominate.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Failure to nominate. 959.28 Section 959.28 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Committee § 959.28 Failure to nominate. If nominations are not made within the time and...
7 CFR 930.25 - Failure to nominate.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 8 2013-01-01 2013-01-01 false Failure to nominate. 930.25 Section 930.25 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Administrative Body § 930.25 Failure to nominate. If nominations are not made within the time and in the manner...

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