Science.gov

Sample records for adjusted effect estimates

  1. Lasso adjustments of treatment effect estimates in randomized experiments

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-07-01

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

  3. Estimating the average treatment effects of nutritional label use using subclassification with regression adjustment.

    PubMed

    Lopez, Michael J; Gutman, Roee

    2014-11-28

    Propensity score methods are common for estimating a binary treatment effect when treatment assignment is not randomized. When exposure is measured on an ordinal scale (i.e. low-medium-high), however, propensity score inference requires extensions which have received limited attention. Estimands of possible interest with an ordinal exposure are the average treatment effects between each pair of exposure levels. Using these estimands, it is possible to determine an optimal exposure level. Traditional methods, including dichotomization of the exposure or a series of binary propensity score comparisons across exposure pairs, are generally inadequate for identification of optimal levels. We combine subclassification with regression adjustment to estimate transitive, unbiased average causal effects across an ordered exposure, and apply our method on the 2005-2006 National Health and Nutrition Examination Survey to estimate the effects of nutritional label use on body mass index.

  4. Adjusting for observational secondary treatments in estimating the effects of randomized treatments.

    PubMed

    Zhang, Min; Wang, Yanping

    2013-07-01

    In randomized clinical trials, for example, on cancer patients, it is not uncommon that patients may voluntarily initiate a secondary treatment postrandomization, which needs to be properly adjusted for in estimating the "true" effects of randomized treatments. As an alternative to the approach based on a marginal structural Cox model (MSCM) in Zhang and Wang [(2012). Estimating treatment effects from a randomized trial in the presence of a secondary treatment. Biostatistics 13, 625-636], we propose methods that treat the time to start a secondary treatment as a dependent censoring process, which is handled separately from the usual censoring such as the loss to follow-up. Two estimators are proposed, both based on the idea of inversely weighting by the probability of having not started a secondary treatment yet. The second estimator focuses on improving efficiency of inference by a robust covariate-adjustment that does not require any additional assumptions. The proposed methods are evaluated and compared with the MSCM-based method in terms of bias and variance tradeoff using simulations and application to a cancer clinical trial.

  5. Adjusting effect estimates for unmeasured confounding with validation data using propensity score calibration

    PubMed Central

    Stürmer, Til; Schneeweiss, Sebastian; Avorn, Jerry; Glynn, Robert J

    2006-01-01

    Often important confounders are not available in studies. Sensitivity analyses based on the relation of single, but not multiple, unmeasured confounders with an exposure of interest in a separate validation study have been proposed. The authors controlled for measured confounding in the main cohort using propensity scores (PS) and addressed unmeasured confounding by estimating two additional PS in a validation study. The ‘error-prone’ PS exclusively used information available in the main cohort. The ‘gold-standard’ PS additionally included covariates available only in the validation study. Based on these two PS in the validation study, regression calibration was applied to adjust regression coefficients. This propensity score calibration (PSC) adjusts for unmeasured confounding in cohort studies with validation data under certain, usually untestable, assumptions. PSC was used to assess nonsteroidal antiinflammatory drugs (NSAID) and 1-year mortality in a large cohort of elderly. ‘Traditional’ adjustment resulted in a relative risk (RR) in NSAID users of 0.80 (95% confidence interval: 0.77–0.83) compared to an unadjusted RR of 0.68 (0.66–0.71). Application of PSC resulted in a more plausible RR of 1.06 (1.00–1.12). Until validity and limitations of PSC have been assessed in different settings, the method should be seen as a sensitivity analysis. PMID:15987725

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

    PubMed

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

    2014-01-10

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2013-01-01

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

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

    PubMed

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

    2016-09-10

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

  10. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  11. Applying risk adjusted cost-effectiveness (RAC-E) analysis to hospitals: estimating the costs and consequences of variation in clinical practice.

    PubMed

    Karnon, Jonathan; Caffrey, Orla; Pham, Clarabelle; Grieve, Richard; Ben-Tovim, David; Hakendorf, Paul; Crotty, Maria

    2013-06-01

    Cost-effectiveness analysis is well established for pharmaceuticals and medical technologies but not for evaluating variations in clinical practice. This paper describes a novel methodology--risk adjusted cost-effectiveness (RAC-E)--that facilitates the comparative evaluation of applied clinical practice processes. In this application, risk adjustment is undertaken with a multivariate matching algorithm that balances the baseline characteristics of patients attending different settings (e.g., hospitals). Linked, routinely collected data are used to analyse patient-level costs and outcomes over a 2-year period, as well as to extrapolate costs and survival over patient lifetimes. The study reports the relative cost-effectiveness of alternative forms of clinical practice, including a full representation of the statistical uncertainty around the mean estimates. The methodology is illustrated by a case study that evaluates the relative cost-effectiveness of services for patients presenting with acute chest pain across the four main public hospitals in South Australia. The evaluation finds that services provided at two hospitals were dominated, and of the remaining services, the more effective hospital gained life years at a low mean additional cost and had an 80% probability of being the most cost-effective hospital at realistic cost-effectiveness thresholds. Potential determinants of the estimated variation in costs and effects were identified, although more detailed analyses to identify specific areas of variation in clinical practice are required to inform improvements at the less cost-effective institutions.

  12. 42 CFR 403.750 - Estimate of expenditures and adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

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

    SciTech Connect

    Whitfield, R.G.

    1997-06-30

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

  14. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  15. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  16. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  17. 28 CFR 100.19 - Adjustments to agreement estimate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

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

    PubMed

    Donoghoe, Mark W; Marschner, Ian C

    2016-08-15

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

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

    NASA Astrophysics Data System (ADS)

    Pegram, Geoff; Bardossy, Andras; Sinclair, Scott

    2016-04-01

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

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

    SciTech Connect

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

    2014-04-14

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

  1. 15 CFR 6.5 - Effective date of adjustments.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... INFLATION ADJUSTMENTS § 6.5 Effective date of adjustments. The adjustments made by § 6.4 of this part, of... December 7, 2012, and before the effective date of any future inflation adjustment thereto made...

  2. 15 CFR 6.5 - Effective date of adjustments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... INFLATION ADJUSTMENTS § 6.5 Effective date of adjustments. The adjustments made by § 6.4 of this part, of... December 7, 2012, and before the effective date of any future inflation adjustment thereto made...

  3. 15 CFR 6.5 - Effective date of adjustments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... INFLATION ADJUSTMENTS § 6.5 Effective date of adjustments. The adjustments made by § 6.4 of this part, of... December 11, 2008, and before the effective date of any future inflation adjustment thereto made...

  4. 15 CFR 6.5 - Effective date of adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... INFLATION ADJUSTMENTS § 6.5 Effective date of adjustments. The adjustments made by § 6.4 of this part, of... December 11, 2008, and before the effective date of any future inflation adjustment thereto made...

  5. 15 CFR 6.5 - Effective date of adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INFLATION ADJUSTMENTS § 6.5 Effective date of adjustments. The adjustments made by § 6.4 of this part, of... December 11, 2008, and before the effective date of any future inflation adjustment thereto made...

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

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

    USGS Publications Warehouse

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

    2013-01-01

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

  8. Repetitive Adjustment to Estimate the Electric Current Sources in a Nerve Fiber with Magnetic Field Measurement

    NASA Astrophysics Data System (ADS)

    Hayami, Takehito; Mishima, Yukuo; Hiwaki, Osamu

    Magnetic field measuring equipment provides us the way to examine the active position of a peripheral nerve without contact or invasion. To develop a process to estimate the position precisely, simulation study of the magnetic field induced by a myelinated nerve fiber was executed. The electric current sources around the active position of a nerve fiber can be approximated as a pair of electric current dipoles, which represent depolarization and repolarization respectively. Therefore the current sources to estimate from the detected pattern of the magnetic field were modeled as a pair of electric current dipoles. A repetitive adjustment process was proposed as an effective method to find the appropriate positions of the dipoles as the sources of the magnetic fields.

  9. Estimating Statistical Power When Making Adjustments for Multiple Tests

    ERIC Educational Resources Information Center

    Porter, Kristin E.

    2016-01-01

    In recent years, there has been increasing focus on the issue of multiple hypotheses testing in education evaluation studies. In these studies, researchers are typically interested in testing the effectiveness of an intervention on multiple outcomes, for multiple subgroups, at multiple points in time or across multiple treatment groups. When…

  10. Renal Drug Dosage Adjustment According to Estimated Creatinine Clearance in Hospitalized Patients With Heart Failure.

    PubMed

    Altunbas, Gokhan; Yazc, Mehmet; Solak, Yalcin; Gul, Enes E; Kayrak, Mehmet; Kaya, Zeynettin; Akilli, Hakan; Aribas, Alpay; Gaipov, Abduzhappar; Yazc, Raziye; Ozdemir, Kurtulus

    2016-01-01

    It is of clinical importance to determine creatinine clearance and adjust doses of prescribed drugs accordingly in patients with heart failure to prevent untoward effects. There is a scarcity of studies in the literature investigating this issue particularly in patients with heart failure, in whom many have impaired kidney function. The purpose of this study was to determine the degree of awareness of medication prescription as to creatinine clearance in patients hospitalized with heart failure. Patients hospitalized with a diagnosis of heart failure were retrospectively evaluated. Among screened charts, patients with left ventricular ejection fraction <40% and an estimated glomerular filtration rate (eGFR) of ≤50 mL/min were included in the analysis. The medications and respective doses prescribed at discharge were recorded. Medications requiring renal dose adjustment were determined and evaluated for appropriate dosing according to eGFR. A total of 388 patients with concomitant heart failure and renal dysfunction were included in the study. The total number of prescribed medications was 2808 and 48.3% (1357 medications) required renal dose adjustment. Of the 1357 medications, 12.6% (171 medications) were found to be inappropriately prescribed according to eGFR. The most common inappropriately prescribed medications were famotidine, metformin, perindopril, and ramipril. A significant portion of medications used in heart failure requires dose adjustment. Our results showed that in a typical cohort of patients with heart failure, many drugs are prescribed at inappropriately high doses according to creatinine clearance. Awareness should be increased among physicians caring for patients with heart failure to prevent adverse events related to medications.

  11. 26 CFR 1.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Abatements, Credits, and Refunds § 1.6425-1 Adjustment of overpayment of estimated income tax by corporation. (a) In general. Any corporation which has made an overpayment of estimated income tax for a taxable year beginning after December...

  12. 26 CFR 1.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Abatements, Credits, and Refunds § 1.6425-1 Adjustment of overpayment of estimated income tax by corporation. (a) In general. Any corporation which has made an overpayment of estimated income tax for a taxable year beginning after...

  13. 26 CFR 1.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Abatements, Credits, and Refunds § 1.6425-1 Adjustment of overpayment of estimated income tax by corporation. (a) In general. Any corporation which has made an overpayment of estimated income tax for a taxable year beginning after...

  14. 26 CFR 1.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Abatements, Credits, and Refunds § 1.6425-1 Adjustment of overpayment of estimated income tax by corporation. (a) In general. Any corporation which has made an overpayment of estimated income tax for a taxable year beginning after...

  15. 26 CFR 1.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Abatements, Credits, and Refunds § 1.6425-1 Adjustment of overpayment of estimated income tax by corporation. (a) In general. Any corporation which has made an overpayment of estimated income tax for a taxable year beginning after...

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

    NASA Astrophysics Data System (ADS)

    Zhang, Zhibin; Liu, Xiang

    2014-10-01

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

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

    USGS Publications Warehouse

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

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  19. 26 CFR 301.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... income tax by corporation. For regulations under section 6425, see §§ 1.6425-1 to 1.6425-3, inclusive, of this chapter (Income Tax Regulations). ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Adjustment of overpayment of estimated...

  20. 26 CFR 301.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... income tax by corporation. For regulations under section 6425, see §§ 1.6425-1 to 1.6425-3, inclusive, of this chapter (Income Tax Regulations). ... 26 Internal Revenue 18 2011-04-01 2011-04-01 false Adjustment of overpayment of estimated...

  1. 26 CFR 301.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... income tax by corporation. For regulations under section 6425, see §§ 1.6425-1 to 1.6425-3, inclusive, of this chapter (Income Tax Regulations). ... 26 Internal Revenue 18 2012-04-01 2012-04-01 false Adjustment of overpayment of estimated...

  2. 26 CFR 301.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... income tax by corporation. For regulations under section 6425, see §§ 1.6425-1 to 1.6425-3, inclusive, of this chapter (Income Tax Regulations). ... 26 Internal Revenue 18 2014-04-01 2014-04-01 false Adjustment of overpayment of estimated...

  3. 26 CFR 301.6425-1 - Adjustment of overpayment of estimated income tax by corporation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... income tax by corporation. For regulations under section 6425, see §§ 1.6425-1 to 1.6425-3, inclusive, of this chapter (Income Tax Regulations). ... 26 Internal Revenue 18 2013-04-01 2013-04-01 false Adjustment of overpayment of estimated...

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

    USGS Publications Warehouse

    Cohn, T.A.

    2005-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Niu, Chengying

    2016-06-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    USGS Publications Warehouse

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

    2011-01-01

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

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

    USGS Publications Warehouse

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

    2011-01-01

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

  9. Dynamically adjustable foot-ground contact model to estimate ground reaction force during walking and running.

    PubMed

    Jung, Yihwan; Jung, Moonki; Ryu, Jiseon; Yoon, Sukhoon; Park, Sang-Kyoon; Koo, Seungbum

    2016-03-01

    Human dynamic models have been used to estimate joint kinetics during various activities. Kinetics estimation is in demand in sports and clinical applications where data on external forces, such as the ground reaction force (GRF), are not available. The purpose of this study was to estimate the GRF during gait by utilizing distance- and velocity-dependent force models between the foot and ground in an inverse-dynamics-based optimization. Ten males were tested as they walked at four different speeds on a force plate-embedded treadmill system. The full-GRF model whose foot-ground reaction elements were dynamically adjusted according to vertical displacement and anterior-posterior speed between the foot and ground was implemented in a full-body skeletal model. The model estimated the vertical and shear forces of the GRF from body kinematics. The shear-GRF model with dynamically adjustable shear reaction elements according to the input vertical force was also implemented in the foot of a full-body skeletal model. Shear forces of the GRF were estimated from body kinematics, vertical GRF, and center of pressure. The estimated full GRF had the lowest root mean square (RMS) errors at the slow walking speed (1.0m/s) with 4.2, 1.3, and 5.7% BW for anterior-posterior, medial-lateral, and vertical forces, respectively. The estimated shear forces were not significantly different between the full-GRF and shear-GRF models, but the RMS errors of the estimated knee joint kinetics were significantly lower for the shear-GRF model. Providing COP and vertical GRF with sensors, such as an insole-type pressure mat, can help estimate shear forces of the GRF and increase accuracy for estimation of joint kinetics. PMID:26979885

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

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

    USGS Publications Warehouse

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

    2014-01-01

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

  12. Research on mechanism and application of effect of adjustment errors in aspheric surface stitching interferometry

    NASA Astrophysics Data System (ADS)

    Qiao, Yujing; Zhang, Hongxin; Lv, Ning; Tang, Yanchao; Li, Junshi

    2014-11-01

    Due to the existence of imprecise fitting of subapertures' overlap zone, the accumulation of adjustment errors is significant during the measurement of aspheric surface by stitching interferometry. Theoretical analysis indicates that the effect and the appearance of three-direction adjustment errors accords with that of Seidel aberration, of which the axial error leads defocus, third-order spherical aberration and higher-order errors of wave front distribution. Based on the analysis we have made, a correction model has been established, and the estimated values of adjustment errors have been acquired. By correcting the higher-order aberration in the model, fitting precision of subapertures' overlap zone can be improved. Experiment for comparison shows that, after fitting, the value of both residual error and uncertainty of measurement become smaller than those values obtained by traditional correction method of three-direction adjustment error, which proves that the stitching precision of proposed method is higher.

  13. The Bivalency Effect: Evidence for Flexible Adjustment of Cognitive Control

    ERIC Educational Resources Information Center

    Rey-Mermet, Alodie; Meier, Beat

    2012-01-01

    When bivalent stimuli (i.e., stimuli with features for two different tasks) appear occasionally, performance is slower on subsequent univalent stimuli. This "bivalency effect" reflects an adjustment of cognitive control arising from the more demanding context created by bivalent stimuli. So far, it has been investigated only on task switch trials,…

  14. Order Effects in Belief Updating: The Belief-Adjustment Model.

    ERIC Educational Resources Information Center

    Hogarth, Robin M.; Einhorn, Hillel J.

    1992-01-01

    A theory of the updating of beliefs over time is presented that explicitly accounts for order-effect phenomena as arising from the interaction of information-processing strategies and task characteristics. The belief-adjustment model is supported by 5 experiments involving 192 adult subjects. (SLD)

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

    2002-07-19

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

  16. Estimating covariate-adjusted measures of diagnostic accuracy based on pooled biomarker assessments.

    PubMed

    McMahan, Christopher S; McLain, Alexander C; Gallagher, Colin M; Schisterman, Enrique F

    2016-07-01

    There is a need for epidemiological and medical researchers to identify new biomarkers (biological markers) that are useful in determining exposure levels and/or for the purposes of disease detection. Often this process is stunted by high testing costs associated with evaluating new biomarkers. Traditionally, biomarker assessments are individually tested within a target population. Pooling has been proposed to help alleviate the testing costs, where pools are formed by combining several individual specimens. Methods for using pooled biomarker assessments to estimate discriminatory ability have been developed. However, all these procedures have failed to acknowledge confounding factors. In this paper, we propose a regression methodology based on pooled biomarker measurements that allow the assessment of the discriminatory ability of a biomarker of interest. In particular, we develop covariate-adjusted estimators of the receiver-operating characteristic curve, the area under the curve, and Youden's index. We establish the asymptotic properties of these estimators and develop inferential techniques that allow one to assess whether a biomarker is a good discriminator between cases and controls, while controlling for confounders. The finite sample performance of the proposed methodology is illustrated through simulation. We apply our methods to analyze myocardial infarction (MI) data, with the goal of determining whether the pro-inflammatory cytokine interleukin-6 is a good predictor of MI after controlling for the subjects' cholesterol levels. PMID:26927583

  17. Background Suppression Effects on Signal Estimation

    SciTech Connect

    Burr, Tom

    2008-01-01

    Gamma detectors at border crossings are intended to detect illicit nuclear material. One performance challenge involves the fact that vehicles suppress the natural background, thus potentially reducing detection probability for threat items. Methods to adjust for background suppression have been considered in related but different settings. Here, methods to adjust for background suppression are tested in the context of signal estimation. Adjustment methods include several clustering options. We find that for the small-to-moderate suppression magnitudes exhibited in the analyzed data, suppression adjustment is only moderatel helpful in locating the signal peak, and in estimating its width or magnitude.

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

    PubMed

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

    2013-01-15

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

  19. Validity of methods for model selection, weighting for model uncertainty, and small sample adjustment in capture-recapture estimation.

    PubMed

    Hook, E B; Regal, R R

    1997-06-15

    In log-linear capture-recapture approaches to population size, the method of model selection may have a major effect upon the estimate. In addition, the estimate may also be very sensitive if certain cells are null or very sparse, even with the use of multiple sources. The authors evaluated 1) various approaches to the issue of model uncertainty and 2) a small sample correction for three or more sources recently proposed by Hook and Regal. The authors compared the estimates derived using 1) three different information criteria that included Akaike's Information Criterion (AIC) and two alternative formulations of the Bayesian Information Criterion (BIC), one proposed by Draper ("two pi") and one by Schwarz ("not two pi"); 2) two related methods of weighting estimates associated with models; 3) the independent model; and 4) the saturated model, with the known totals in 20 different populations studied by five separate groups of investigators. For each method, we also compared the estimate derived with or without the proposed small sample correction. At least in these data sets, the use of AIC appeared on balance to be preferable. The BIC formulation suggested by Draper appeared slightly preferable to that suggested by Schwarz. Adjustment for model uncertainty appears to improve results slightly. The proposed small sample correction appeared to diminish relative log bias but only when sparse cells were present. Otherwise, its use tended to increase relative log bias. Use of the saturated model (with or without the small sample correction) appears to be optimal if the associated interval is not uselessly large, and if one can plausibly exclude an all-source interaction. All other approaches led to an estimate that was too low by about one standard deviation.

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

    PubMed

    Gugiu, Daniela; Dumitrache, Ion

    2005-01-01

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

  1. Estimating restricted mean treatment effects with stacked survival models.

    PubMed

    Wey, Andrew; Vock, David M; Connett, John; Rudser, Kyle

    2016-08-30

    The difference in restricted mean survival times between two groups is a clinically relevant summary measure. With observational data, there may be imbalances in confounding variables between the two groups. One approach to account for such imbalances is estimating a covariate-adjusted restricted mean difference by modeling the covariate-adjusted survival distribution and then marginalizing over the covariate distribution. Because the estimator for the restricted mean difference is defined by the estimator for the covariate-adjusted survival distribution, it is natural to expect that a better estimator of the covariate-adjusted survival distribution is associated with a better estimator of the restricted mean difference. We therefore propose estimating restricted mean differences with stacked survival models. Stacked survival models estimate a weighted average of several survival models by minimizing predicted error. By including a range of parametric, semi-parametric, and non-parametric models, stacked survival models can robustly estimate a covariate-adjusted survival distribution and, therefore, the restricted mean treatment effect in a wide range of scenarios. We demonstrate through a simulation study that better performance of the covariate-adjusted survival distribution often leads to better mean squared error of the restricted mean difference although there are notable exceptions. In addition, we demonstrate that the proposed estimator can perform nearly as well as Cox regression when the proportional hazards assumption is satisfied and significantly better when proportional hazards is violated. Finally, the proposed estimator is illustrated with data from the United Network for Organ Sharing to evaluate post-lung transplant survival between large-volume and small-volume centers. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26934835

  2. Validation, Replication, and Sensitivity Testing of Heckman-Type Selection Models to Adjust Estimates of HIV Prevalence

    PubMed Central

    Clark, Samuel J.; Houle, Brian

    2014-01-01

    A recent study using Heckman-type selection models to adjust for non-response in the Zambia 2007 Demographic and Health Survey (DHS) found a large correction in HIV prevalence for males. We aim to validate this finding, replicate the adjustment approach in other DHSs, apply the adjustment approach in an external empirical context, and assess the robustness of the technique to different adjustment approaches. We used 6 DHSs, and an HIV prevalence study from rural South Africa to validate and replicate the adjustment approach. We also developed an alternative, systematic model of selection processes and applied it to all surveys. We decomposed corrections from both approaches into rate change and age-structure change components. We are able to reproduce the adjustment approach for the 2007 Zambia DHS and derive results comparable with the original findings. We are able to replicate applying the approach in several other DHSs. The approach also yields reasonable adjustments for a survey in rural South Africa. The technique is relatively robust to how the adjustment approach is specified. The Heckman selection model is a useful tool for assessing the possibility and extent of selection bias in HIV prevalence estimates from sample surveys. PMID:25402333

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

    USGS Publications Warehouse

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

    2013-01-01

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

  4. The occurrence of the filled duration illusion: a comparison of the method of adjustment with the method of magnitude estimation.

    PubMed

    Hasuo, Emi; Nakajima, Yoshitaka; Tomimatsu, Erika; Grondin, Simon; Ueda, Kazuo

    2014-03-01

    A time interval between the onset and the offset of a continuous sound (filled interval) is often perceived to be longer than a time interval between two successive brief sounds (empty interval) of the same physical duration. The present study examined whether and how this phenomenon, sometimes called the filled duration illusion (FDI), occurs for short time intervals (40-520 ms). The investigation was conducted with the method of adjustment (Experiment 1) and the method of magnitude estimation (Experiment 2). When the method of adjustment was used, the FDI did not appear for the majority of the participants, but it appeared clearly for some participants. In the latter case, the amount of the FDI increased as the interval duration lengthened. The FDI was more likely to occur with magnitude estimation than with the method of adjustment. The participants who showed clear FDI with one method did not necessarily show such clear FDI with the other method.

  5. Call Number Adjustment: The Effects on Browsability if No Adjustment Is Made.

    ERIC Educational Resources Information Center

    Rodman, Ruey L.

    In these times of tight budgets, libraries are seeking ways to cut costs, and one area being examined is book processing. This study assesses the impact on the organization of a library collection if the call number is not changed to fit into the shelf list sequence. The research questions examined are: "Is it necessary to adjust the book number…

  6. Social desirability effects on measures of adjustment to university, independence from parents, and self-efficacy.

    PubMed

    Silverthorn, N A; Gekoski, W L

    1995-03-01

    Results of regression analyses on data from 96 first-year undergraduates indicated that social desirability (Jackson and Marlowe-Crowne Social Desirability Scales), particularly scores on the Jackson scale, is related strongly to scores on measures of adjustment (Student Adaptation to College Questionnaire), self-efficacy (Hale-Fibel Generalized Expectation for Success Scale), and independence (Psychological Separation Inventory) from mother, but not from father. In addition, both the Jackson and Marlowe-Crowne scales were correlated highly. Independence from parents and self-efficacy each continued to show a relationship with adjustment to university after social desirability effects were removed. Failure to remove the effect(s) of social desirability from the present measures is likely to lead to inflated estimates of their relation to each other or to other measures.

  7. The portion size effect on food intake. An anchoring and adjustment process?

    PubMed

    Marchiori, David; Papies, Esther K; Klein, Olivier

    2014-10-01

    People consistently over-eat when served a large compared with a small (appropriate) portion of food. However, the mechanism underlying this so-called portion size effect is not well understood. We argue that the process of anchoring and adjustment naturally describes this effect, such that the size of a presented portion works as an anchor that strongly influences consumption. The classical anchoring and adjustment paradigm was applied to six hypothetical eating situations. Participants were asked to imagine being served either a small or a large portion of food (i.e., low and high anchor) and to indicate whether they would consume more or less than this amount. Then, they indicated how much they would eat. These estimates were compared with a no-anchor condition where participants did not imagine a specific portion size but only indicated how much they would eat. In addition, half of participants in the anchoring conditions received a discounting instruction stating that the portion size they had been asked to imagine was randomly selected and thus not informative for their consumption estimate. As expected, participants who imagined to be served larger portions estimated to consume significantly more food than participants in the no-anchor condition, and participants who imagined to be served smaller portions estimated to consume significantly less food than participants in the no-anchor condition. The discounting manipulation did not reduce this effect of the anchors. We suggest that the process of anchoring and adjustment may provide a useful framework to understand the portion size effect and we discuss implications of this perspective.

  8. Baroclinic adjustment. [parameterization of eddy flux effects on atmospheric temperature

    NASA Technical Reports Server (NTRS)

    Stone, P. H.

    1978-01-01

    A detailed comparison is presented of the actual shear in the atmosphere with the critical shear given by the two-layer model of Phillips (1954), in which there is a critical temperature gradient separating stable conditions from baroclinically unstable ones. A very simple parameterization of the effect of eddy fluxes on atmospheric temperature is suggested, where the parameterization includes beta effects. The parameterization is illustrated by applying it in a one-dimensional heat-balance climate model. Enhancement of the eddy flux in a continuous atmosphere under supercritical conditions is stressed. This enhancement leads to a negative feedback between the meridional eddy flux of heat and the meridional temperature gradient. The feedback restricts gradients to values near the critical value, a process referred to as baroclinic adjustment. This should facilitate the development of simple climate models involving feedbacks associated with both the meridional vertical temperature structure.

  9. First-order correct bootstrap support adjustments for splits that allow hypothesis testing when using maximum likelihood estimation.

    PubMed

    Susko, Edward

    2010-07-01

    The most frequent measure of phylogenetic uncertainty for splits is bootstrap support. Although large bootstrap support intuitively suggests that a split in a tree is well supported, it has not been clear how large bootstrap support needs to be to conclude that there is significant evidence that a hypothesized split is present. Indeed, recent work has shown that bootstrap support is not first-order correct and thus cannot be directly used for hypothesis testing. We present methods that adjust bootstrap support values in a maximum likelihood (ML) setting so that they have an interpretation corresponding to P values in conventional hypothesis testing; for instance, adjusted bootstrap support larger than 95% occurs only 5% of the time if the split is not present. Through examples and simulation settings, it is found that adjustments always increase the level of support. We also find that the nature of the adjustment is fairly constant across parameter settings. Finally, we consider adjustments that take into account the data-dependent nature of many hypotheses about splits: the hypothesis that they are present is being tested because they are in the tree estimated through ML. Here, in contrast, we find that bootstrap probability often needs to be adjusted downwards.

  10. Remedial action and feedback processing in a time-estimation task: evidence for a role of the rostral cingulate zone in behavioral adjustments without learning.

    PubMed

    van der Veen, Frederik M; Röder, Christian H; Mies, Gabry W; van der Lugt, Aad; Smits, Marion

    2011-01-01

    The present study examined the role of the rostral cingulate zone (RCZ) in feedback processing, and especially focused on effects of modality of the feedback stimulus and remedial action. Participants performed a time-estimation task in which they had to estimate a 1-second interval. After the estimation participants received verbal (correct/false) or facial (fearful face/happy face) feedback. Percentage of positive and negative feedback was kept at 50% by dynamically adjusting the interval in which estimations were labeled correct. Contrary to predictions of the reinforcement learning theory, which predicts more RCZ activation when the outcome of behavior is worse than expected, we found that the RCZ was more active after positive feedback than after negative feedback, independent of the modality of the feedback stimulus. More in line with the suggested role of the RCZ in reinforcement learning was the finding that the RCZ was more active after negative feedback that was followed by a correct adjustment as compared to negative feedback followed by an incorrect adjustment. Both findings can be explained in terms of the RCZ being involved in facilitating remedial action as opposed to the suggested signaling function (outcome is worse than expected) proposed by the reinforcement learning theory.

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

    PubMed Central

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

    2014-01-01

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

  12. The acoustic effect of vocal tract adjustments in zebra finches

    PubMed Central

    Riede, Tobias; Schilling, Nadja; Goller, Franz

    2012-01-01

    Vocal production in songbirds requires the control of the respiratory system, the syrinx as sound source and the vocal tract as acoustic filter. Vocal tract movements consist of beak, tongue and hyoid movements which change the volume of the oropharyngeal-esophageal cavity (OEC), glottal movements and tracheal length changes. The respective contributions of each movement to filter properties are not completely understood, but the effects of this filtering are thought to be very important for acoustic communication in birds. One of the most striking movements of the upper vocal tract during vocal behavior in songbirds involves the OEC. This study measured the acoustic effect of OEC adjustments in zebra finches by comparing resonance acoustics between an utterance with OEC expansion (calls) and a similar utterance without OEC expansion (respiratory sounds induced by a bilateral syringeal denervation). X-ray cineradiography confirmed the presence of an OEC motor pattern during song and call production, and a custom-built Hall-effect collar system confirmed that OEC expansion movements were not present during respiratory sounds. The spectral emphasis during zebra finch call production ranging between 2.5 and 5 kHz was not present during respiratory sounds, indicating strongly that it can be attributed to the OEC expansion. PMID:23085986

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

    SciTech Connect

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

    2015-03-25

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

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

    DOE PAGES

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

    2015-03-25

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

  15. The Effect of Articulatory Adjustment on Reducing Hypernasality

    ERIC Educational Resources Information Center

    Rong, Panying; Kuehn, David

    2012-01-01

    Purpose: With the goal of using articulatory adjustments to reduce hypernasality, this study utilized an articulatory synthesis model (Childers, 2000) to simulate the adjustment of articulatory configurations with an open velopharynx to achieve the same acoustic goal as normal speech simulated with a closed velopharynx. Method: To examine the…

  16. The Effect of Family Communication Patterns on Adopted Adolescent Adjustment

    PubMed Central

    Rueter, Martha A.

    2008-01-01

    Adoption and family communication both affect adolescent adjustment. We proposed that adoption status and family communication interact such that adopted adolescents in families with certain communication patterns are at greater risk for adjustment problems. We tested this hypothesis using a community-based sample of 384 adoptive and 208 nonadoptive families. Adolescents in these families were, on average, 16 years of age. The results supported our hypothesis. Adopted adolescents were at significantly greater risk for adjustment problems compared to nonadopted adolescents in families that emphasized conformity orientation without conversation orientation and in families that emphasized neither conformity nor conversation orientation. Adolescents in families emphasizing conversation orientation were at lower risk for adjustment problems, regardless of adoption status. PMID:19649145

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

    USGS Publications Warehouse

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

    2012-01-01

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

  18. Estimation of treatment effects based on possibly misspecified Cox regression.

    PubMed

    Hattori, Satoshi; Henmi, Masayuki

    2012-10-01

    In randomized clinical trials, a treatment effect on a time-to-event endpoint is often estimated by the Cox proportional hazards model. The maximum partial likelihood estimator does not make sense if the proportional hazard assumption is violated. Xu and O'Quigley (Biostatistics 1:423-439, 2000) proposed an estimating equation, which provides an interpretable estimator for the treatment effect under model misspecification. Namely it provides a consistent estimator for the log-hazard ratio among the treatment groups if the model is correctly specified, and it is interpreted as an average log-hazard ratio over time even if misspecified. However, the method requires the assumption that censoring is independent of treatment group, which is more restricted than that for the maximum partial likelihood estimator and is often violated in practice. In this paper, we propose an alternative estimating equation. Our method provides an estimator of the same property as that of Xu and O'Quigley under the usual assumption for the maximum partial likelihood estimation. We show that our estimator is consistent and asymptotically normal, and derive a consistent estimator of the asymptotic variance. If the proportional hazards assumption holds, the efficiency of the estimator can be improved by applying the covariate adjustment method based on the semiparametric theory proposed by Lu and Tsiatis (Biometrika 95:679-694, 2008). PMID:22527680

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

    PubMed

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

    2016-12-01

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

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

    PubMed

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

    2016-12-01

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

  1. Slope Estimation for Bivariate Longitudinal Outcomes Adjusting for Informative Right Censoring Using Discrete Survival Model: Application to the Renal Transplant Cohort.

    PubMed

    Jaffa, Miran A; Woolson, Robert F; Lipsitz, Stuart R

    2011-04-01

    Patients undergoing renal transplantation are prone to graft failure which causes lost of follow-up measures on their blood urea nitrogen and serum creatinine levels. These two outcomes are measured repeatedly over time to assess renal function following transplantation. Loss of follow-up on these bivariate measures results in informative right censoring, a common problem in longitudinal data that should be adjusted for so that valid estimates are obtained. In this study, we propose a bivariate model that jointly models these two longitudinal correlated outcomes and generates population and individual slopes adjusting for informative right censoring using a discrete survival approach. The proposed approach is applied to the clinical dataset of patients who had undergone renal transplantation. A simulation study validates the effectiveness of the approach.

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

    PubMed

    Chowdhury, Sourangsu; Dey, Sagnik

    2016-05-01

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

  3. Covariate adjustment of event histories estimated from Markov chains: the additive approach.

    PubMed

    Aalen, O O; Borgan, O; Fekjaer, H

    2001-12-01

    Markov chain models are frequently used for studying event histories that include transitions between several states. An empirical transition matrix for nonhomogeneous Markov chains has previously been developed, including a detailed statistical theory based on counting processes and martingales. In this article, we show how to estimate transition probabilities dependent on covariates. This technique may, e.g., be used for making estimates of individual prognosis in epidemiological or clinical studies. The covariates are included through nonparametric additive models on the transition intensities of the Markov chain. The additive model allows for estimation of covariate-dependent transition intensities, and again a detailed theory exists based on counting processes. The martingale setting now allows for a very natural combination of the empirical transition matrix and the additive model, resulting in estimates that can be expressed as stochastic integrals, and hence their properties are easily evaluated. Two medical examples will be given. In the first example, we study how the lung cancer mortality of uranium miners depends on smoking and radon exposure. In the second example, we study how the probability of being in response depends on patient group and prophylactic treatment for leukemia patients who have had a bone marrow transplantation. A program in R and S-PLUS that can carry out the analyses described here has been developed and is freely available on the Internet. PMID:11764270

  4. Effects of Relational Authenticity on Adjustment to College

    ERIC Educational Resources Information Center

    Lenz, A. Stephen; Holman, Rachel L.; Lancaster, Chloe; Gotay, Stephanie G.

    2016-01-01

    The authors examined the association between relational health and student adjustment to college. Data were collected from 138 undergraduate students completing their 1st semester at a large university in the mid-southern United States. Regression analysis indicated that higher levels of relational authenticity were a predictor of success during…

  5. Effective Report Writing in Vocational Evaluation and Work Adjustment Programs.

    ERIC Educational Resources Information Center

    Esser, Thomas J.

    The document serves as a guideline to report writing for vocational evaluation and work adjustment programs, providing general principles for content with the aim of developing some uniformity in report organization. Common problems in report writing are described from the reader's and writer's perspective. Basic principles are listed which should…

  6. Mediating Effects of Relationships with Mentors on College Adjustment

    ERIC Educational Resources Information Center

    Lenz, A. Stephen

    2014-01-01

    This study examined the relationship between student adjustment to college and relational health with peers, mentors, and the community. Data were collected from 80 undergraduate students completing their first semester of course work at a large university in the mid-South. A series of simultaneous multiple regression analyses indicated that…

  7. Adolescent Leisure Dimensions, Psychosocial Adjustment, and Gender Effects

    ERIC Educational Resources Information Center

    Bradley, Graham L.; Inglis, Brad C.

    2012-01-01

    Leisure provides the context for much of adolescent behaviour and development. While both theory and research point to the benefits of participation in leisure activities that are highly structured, the association between structured leisure and psychosocial adjustment is not uniformly high. This paper presents a model of adolescent leisure…

  8. Continuity in Adolescent Career Preparation and Its Effects on Adjustment

    ERIC Educational Resources Information Center

    Skorikov, Vladimir

    2007-01-01

    Career preparation represents a major developmental task of adolescence, which has not received sufficient attention in empirical research on career development. Thus, this study was designed to examine the structure, continuity, and change in adolescent career preparation and its relationships with adjustment. The data were collected from a…

  9. The Effect of Childhood Trauma on Later Psychological Adjustment

    ERIC Educational Resources Information Center

    Browne, Caroline; Winkelman, Cecelia

    2007-01-01

    This study examined whether adult attachment and cognitive distortion mediate the relationship between childhood trauma and psychological adjustment. The participants were 219 students (40 men and 117 women) enrolled in a university degree. Participants completed the Childhood Trauma Questionnaire, which assessed retrospective accounts of…

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

    PubMed

    Gibson, A; Jorm, L; McIntyre, P

    2015-09-01

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

  11. Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

    PubMed

    Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

    2016-09-01

    Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high.

  12. Viscosity-adjusted estimation of pressure head and pump flow with quasi-pulsatile modulation of rotary blood pump for a total artificial heart.

    PubMed

    Yurimoto, Terumi; Hara, Shintaro; Isoyama, Takashi; Saito, Itsuro; Ono, Toshiya; Abe, Yusuke

    2016-09-01

    Estimation of pressure and flow has been an important subject for developing implantable artificial hearts. To realize real-time viscosity-adjusted estimation of pressure head and pump flow for a total artificial heart, we propose the table estimation method with quasi-pulsatile modulation of rotary blood pump in which systolic high flow and diastolic low flow phased are generated. The table estimation method utilizes three kinds of tables: viscosity, pressure and flow tables. Viscosity is estimated from the characteristic that differential value in motor speed between systolic and diastolic phases varies depending on viscosity. Potential of this estimation method was investigated using mock circulation system. Glycerin solution diluted with salty water was used to adjust viscosity of fluid. In verification of this method using continuous flow data, fairly good estimation could be possible when differential pulse width modulation (PWM) value of the motor between systolic and diastolic phases was high. In estimation under quasi-pulsatile condition, inertia correction was provided and fairly good estimation was possible when the differential PWM value was high, which was not different from the verification results using continuous flow data. In the experiment of real-time estimation applying moving average method to the estimated viscosity, fair estimation could be possible when the differential PWM value was high, showing that real-time viscosity-adjusted estimation of pressure head and pump flow would be possible with this novel estimation method when the differential PWM value would be set high. PMID:27022734

  13. 20 CFR 340.9 - Effect of adjustment in connection with subsequent payments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Effect of adjustment in connection with subsequent payments. 340.9 Section 340.9 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT RECOVERY OF BENEFITS § 340.9 Effect of adjustment in connection...

  14. Adjustment to the Curve Number Nrcs-Cn to Account for the Vegetation Effect on the Hydrological Processes

    NASA Astrophysics Data System (ADS)

    Gonzalez, A.; Temimi, M.; Khanbilvardi, R.

    2012-12-01

    The objective of this work is to develop an approach that makes use of remotely sensed Greenness Fraction (GF) as a proxy for the vegetation density to automatically adjust the Curve Number model (NRCS-CN) to account for the effect of the changes in vegetation growth on hydrological processes. Daily gauged precipitation-runoff pairs (1948 to 2003) from the MOdel Parameter Estimation EXperiment dataset (MOPEX) over 26 watersheds across the U.S. were used to estimate monthly averaged CNs (CNsim) and then compared to the monthly GF. An adjustment factor was then proposed for the typical static CN inputs which do not account for the vegetation growth over time; the result was a vegetation-adjusted CN (CNveg adj). The improvement in the performance of the NRCS-CN methodology was assessed. The results evidence how the CNveg adj compensates the underestimation of the standard CN (CNstd). The ratio of the estimated runoff using the CNstd (Qstd) to the observed runoff (Qobs) was 0.36; while with the CNveg adj (Qveg adj) was 0.98. The correlation coefficient of simulated and observed runoff when using CNstd and CNveg adj, was 0.42 and 0.92, respectively. Likewise, the Nash-Sutcliffe coefficient of Qstd was -0.92 and 0.85 for Qveg adj. This implies that the adjustment to the CN is crucial for improved hydrological modeling and, therefore, for flood and flash flood monitoring and forecasting.

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

    ERIC Educational Resources Information Center

    Tipton, Elizabeth; Pustejovsky, James E.

    2015-01-01

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

  16. A comparison of bootstrap methods and an adjusted bootstrap approach for estimating the prediction error in microarray classification.

    PubMed

    Jiang, Wenyu; Simon, Richard

    2007-12-20

    This paper first provides a critical review on some existing methods for estimating the prediction error in classifying microarray data where the number of genes greatly exceeds the number of specimens. Special attention is given to the bootstrap-related methods. When the sample size n is small, we find that all the reviewed methods suffer from either substantial bias or variability. We introduce a repeated leave-one-out bootstrap (RLOOB) method that predicts for each specimen in the sample using bootstrap learning sets of size ln. We then propose an adjusted bootstrap (ABS) method that fits a learning curve to the RLOOB estimates calculated with different bootstrap learning set sizes. The ABS method is robust across the situations we investigate and provides a slightly conservative estimate for the prediction error. Even with small samples, it does not suffer from large upward bias as the leave-one-out bootstrap and the 0.632+ bootstrap, and it does not suffer from large variability as the leave-one-out cross-validation in microarray applications.

  17. Metacomprehension Effects Situated within an Anchoring and Adjustment Framework

    ERIC Educational Resources Information Center

    Linderholm, Tracy; Zhao, Qin; Therriault, David J.; Cordell-McNulty, Kristi

    2008-01-01

    Low accuracy levels are often obtained when readers are asked to predict test performance over reading materials. Three investigations further explore the information readers use to make predictions during metacomprehension. Our results show that readers' estimates are influenced by factors such as their initial impression of the reading task,…

  18. Effects of Peer Victimization on Psychological and Academic Adjustment in Early Adolescence

    ERIC Educational Resources Information Center

    Rueger, Sandra Yu; Jenkins, Lyndsay N.

    2014-01-01

    The purpose of the current study is to investigate the effects of frequency of peer victimization experiences on psychological and academic adjustment during early adolescence, with a focus on testing psychological adjustment as a mediator, as well as differences based on gender and type of victimization. The sample in this short-term longitudinal…

  19. Aggressive and Prosocial Peer Group Functioning: Effects on Children's Social, School, and Psychological Adjustment

    ERIC Educational Resources Information Center

    Chung-Hall, Janet; Chen, Xinyin

    2010-01-01

    This study examined the effects of aggressive and prosocial contexts of peer groups on children's socioemotional and school adjustment. Data on informal peer groups, social functioning, and different aspects of adjustment were collected from multiple sources in a sample of elementary school children (149 boys, 181 girls; M age = 10 years).…

  20. The Impact of Statistically Adjusting for Rater Effects on Conditional Standard Errors of Performance Ratings

    ERIC Educational Resources Information Center

    Raymond, Mark R.; Harik, Polina; Clauser, Brian E.

    2011-01-01

    Prior research indicates that the overall reliability of performance ratings can be improved by using ordinary least squares (OLS) regression to adjust for rater effects. The present investigation extends previous work by evaluating the impact of OLS adjustment on standard errors of measurement ("SEM") at specific score levels. In addition, a…

  1. Consequences of self-handicapping: effects on coping, academic performance, and adjustment.

    PubMed

    Zuckerman, M; Kieffer, S C; Knee, C R

    1998-06-01

    Self-handicappers erect impediments to performance to protect their self-esteem. The impediments may interfere with the ability to do well and, as such, may result in poor adjustment. Using a longitudinal design, the present studies examined prospective effects of self-handicapping on coping, academic performance, and several adjustment-related variables (e.g., self-esteem). It was found that, compared to low self-handicappers, high self-handicappers reported higher usage of coping strategies implying withdrawal and negative focus. High self-handicappers performed less well academically, an effect that was mediated in part by poor study habits. Finally, high self-handicapping resulted in poorer adjustment over time, and poorer adjustment resulted in higher self-handicapping over time. These relations are consistent with the idea of a vicious cycle in which self-handicapping and poor adjustment reinforce one another.

  2. Effects of multiple context and cumulative stress on urban children's adjustment in elementary school.

    PubMed

    Morales, Julie R; Guerra, Nancy G

    2006-01-01

    Using longitudinal data collected over 2 years on a sample of 2,745 urban elementary school children (1st-6th graders, ages 6-11 years) from economically disadvantaged communities, effects of stressful experiences within 3 contexts (school, family, neighborhood), cumulative stress, and multiple context stress on 3 indices of children's adjustment (achievement, depression, and aggression) were examined. All 3 stressor contexts were related contemporaneously and longitudinally to negative outcomes across adjustment measures, with differential paths in each predictive model. Cumulative stress was linearly related to increases in adjustment problems but multiple context stress was not related to problematic adjustment beyond effects of cumulative stress alone. The important influence of life events stress on children's adjustment in disadvantaged communities is discussed.

  3. Magnitude and directional effects of marital sex-role incongruence on marital adjustment.

    PubMed

    Li, J T; Caldwell, R A

    1987-03-01

    Economic and social forces have converged to influence the fundamental nature of marriage in the 1980s. Marriages are shifting from the complementary type, in which the husband is employed and the wife cares for the household and children, to the parallel type, in which both spouses are employed and both are responsible for the housework. This study examines the relationship between marital sex role incongruence and marital adjustment. Both the magnitude and the direction of the incongruence are related to marital adjustment level. The study's major hypothesis is that the relationship between marital sex-role incongruence and marital adjustment is a function of both the magnitude of the incongruence and the direction of the disagreement. Couples in the study were recruited from a moderately sized midwestern university community. 103 couples agreed to participate but 73 couples actually returned the questionnaire. Of these 73 couples, 63% were randomly recruited through door-to-door solicitation, 29% were recruited from an evangelical Christian organization and church, and 8% were recruited from acquaintances of the 1st author. After deleting incomplete questionnaires, final sample size was 67 couples. Each member of a marital dyad completed a questionnaire including a Dyadic Adjustment Scale to measure marital adjustment, a Sex-Role Egalitarianism Scale to measure marital sex-role orientation, a Marlowe-Crowne Social Desirability Scale Short Form C to measure social desirability bias, and a demographic information sheet. Findings indicate that direction of incongruence plays a very important role in determining the impact of marital sex-role incongruence on marital adjustment; namely, the greater the incongruence is in the direction of the wife being more egalitarian relative to her husband, the more negative is the estimated impact on marital adjustment. Conversely, the greater the incongruence is in the direction of the husband being more egalitarian than his

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

    PubMed

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

    2015-11-01

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

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

    PubMed

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

    2015-11-01

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

  6. Assessing Longitudinal Change: Adjustment for Regression to the Mean Effects

    ERIC Educational Resources Information Center

    Rocconi, Louis M.; Ethington, Corinna A.

    2009-01-01

    Pascarella (J Coll Stud Dev 47:508-520, 2006) has called for an increase in use of longitudinal data with pretest-posttest design when studying effects on college students. However, such designs that use multiple measures to document change are vulnerable to an important threat to internal validity, regression to the mean. Herein, we discuss a…

  7. The Effects of Grouping Practices and Curricular Adjustments on Achievement

    ERIC Educational Resources Information Center

    Tieso, Carol

    2005-01-01

    The purpose of this study was to examine the effects of curricular (textbook, revised, and differentiated) and grouping (whole, between, and within-class) practices on intermediate students' achievement in mathematics. A pretest-posttest, quasi-experimental design using a stratified random sample of 31 teachers and their students (N = 645) was…

  8. Using Hierarchical Rater Model to Adjust Effect Size

    ERIC Educational Resources Information Center

    Luo, Long

    2012-01-01

    The topic of this research is inference for effect size of a curriculum intervention, which is an important research topic in education. The linear relationship between the outcomes of an intervention and teachers' fidelity, the extent to which the intervention was actually delivered by teachers as intended, is an important component for…

  9. BEclear: Batch Effect Detection and Adjustment in DNA Methylation Data.

    PubMed

    Akulenko, Ruslan; Merl, Markus; Helms, Volkhard

    2016-01-01

    Batch effects describe non-natural variations of, for example, large-scale genomic data sets. If not corrected by suitable numerical algorithms, batch effects may seriously affect the analysis of these datasets. The novel array platform independent software tool BEclear enables researchers to identify those portions of the data that deviate statistically significant from the remaining data and to replace these portions by typical values reconstructed from neighboring data entries based on latent factor models. In contrast to other comparable methods that often use some sort of global normalization of the data, BEclear avoids changing the apparently unaffected parts of the data. We tested the performance of this approach on DNA methylation data for various tumor data sets taken from The Cancer Genome Atlas and compared the results to those obtained with the existing algorithms ComBat, Surrogate Variable Analysis, RUVm and Functional normalization. BEclear constantly performed at par with or better than these methods. BEclear is available as an R package at the Bioconductor project http://bioconductor.org/packages/release/bioc/html/BEclear.html. PMID:27559732

  10. BEclear: Batch Effect Detection and Adjustment in DNA Methylation Data

    PubMed Central

    Akulenko, Ruslan; Merl, Markus; Helms, Volkhard

    2016-01-01

    Batch effects describe non-natural variations of, for example, large-scale genomic data sets. If not corrected by suitable numerical algorithms, batch effects may seriously affect the analysis of these datasets. The novel array platform independent software tool BEclear enables researchers to identify those portions of the data that deviate statistically significant from the remaining data and to replace these portions by typical values reconstructed from neighboring data entries based on latent factor models. In contrast to other comparable methods that often use some sort of global normalization of the data, BEclear avoids changing the apparently unaffected parts of the data. We tested the performance of this approach on DNA methylation data for various tumor data sets taken from The Cancer Genome Atlas and compared the results to those obtained with the existing algorithms ComBat, Surrogate Variable Analysis, RUVm and Functional normalization. BEclear constantly performed at par with or better than these methods. BEclear is available as an R package at the Bioconductor project http://bioconductor.org/packages/release/bioc/html/BEclear.html. PMID:27559732

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

    SciTech Connect

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

    2014-07-15

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

  12. Effects of Accuracy Feedback on Fractal Characteristics of Time Estimation

    PubMed Central

    Kuznetsov, Nikita A.; Wallot, Sebastian

    2011-01-01

    The current experiment investigated the effect of visual accuracy feedback on the structure of variability of time interval estimates in the continuation tapping paradigm. Participants were asked to repeatedly estimate a 1-s interval for a prolonged period of time by tapping their index finger. In some conditions, participants received accuracy feedback after every estimate, whereas in other conditions, no feedback was given. Also, the likelihood of receiving visual feedback was manipulated by adjusting the tolerance band around the 1-s target interval so that feedback was displayed only if the temporal estimate deviated from the target interval by more than 50, 100, or 200 ms respectively. We analyzed the structure of variability of the inter-tap intervals with fractal and multifractal methods that allow for a quantification of complex long-range correlation patterns in the timing performance. Our results indicate that feedback changes the long-range correlation structure of time estimates: Increased amounts of feedback lead to a decrease in fractal long-range correlations, as well to a decrease in the magnitude of local fluctuations in the performance. The multifractal characteristics of the time estimates were not impacted by the presence of accuracy feedback. Nevertheless, most of the data sets show significant multifractal signatures. We interpret these findings as showing that feedback acts to constrain and possibly reorganize timing performance. Implications for mechanistic and complex systems-based theories of timing behavior are discussed. PMID:22046149

  13. Movement Sonification: Effects on Motor Learning beyond Rhythmic Adjustments

    PubMed Central

    Effenberg, Alfred O.; Fehse, Ursula; Schmitz, Gerd; Krueger, Bjoern; Mechling, Heinz

    2016-01-01

    Motor learning is based on motor perception and emergent perceptual-motor representations. A lot of behavioral research is related to single perceptual modalities but during last two decades the contribution of multimodal perception on motor behavior was discovered more and more. A growing number of studies indicates an enhanced impact of multimodal stimuli on motor perception, motor control and motor learning in terms of better precision and higher reliability of the related actions. Behavioral research is supported by neurophysiological data, revealing that multisensory integration supports motor control and learning. But the overwhelming part of both research lines is dedicated to basic research. Besides research in the domains of music, dance and motor rehabilitation, there is almost no evidence for enhanced effectiveness of multisensory information on learning of gross motor skills. To reduce this gap, movement sonification is used here in applied research on motor learning in sports. Based on the current knowledge on the multimodal organization of the perceptual system, we generate additional real-time movement information being suitable for integration with perceptual feedback streams of visual and proprioceptive modality. With ongoing training, synchronously processed auditory information should be initially integrated into the emerging internal models, enhancing the efficacy of motor learning. This is achieved by a direct mapping of kinematic and dynamic motion parameters to electronic sounds, resulting in continuous auditory and convergent audiovisual or audio-proprioceptive stimulus arrays. In sharp contrast to other approaches using acoustic information as error-feedback in motor learning settings, we try to generate additional movement information suitable for acceleration and enhancement of adequate sensorimotor representations and processible below the level of consciousness. In the experimental setting, participants were asked to learn a closed

  14. Movement Sonification: Effects on Motor Learning beyond Rhythmic Adjustments.

    PubMed

    Effenberg, Alfred O; Fehse, Ursula; Schmitz, Gerd; Krueger, Bjoern; Mechling, Heinz

    2016-01-01

    Motor learning is based on motor perception and emergent perceptual-motor representations. A lot of behavioral research is related to single perceptual modalities but during last two decades the contribution of multimodal perception on motor behavior was discovered more and more. A growing number of studies indicates an enhanced impact of multimodal stimuli on motor perception, motor control and motor learning in terms of better precision and higher reliability of the related actions. Behavioral research is supported by neurophysiological data, revealing that multisensory integration supports motor control and learning. But the overwhelming part of both research lines is dedicated to basic research. Besides research in the domains of music, dance and motor rehabilitation, there is almost no evidence for enhanced effectiveness of multisensory information on learning of gross motor skills. To reduce this gap, movement sonification is used here in applied research on motor learning in sports. Based on the current knowledge on the multimodal organization of the perceptual system, we generate additional real-time movement information being suitable for integration with perceptual feedback streams of visual and proprioceptive modality. With ongoing training, synchronously processed auditory information should be initially integrated into the emerging internal models, enhancing the efficacy of motor learning. This is achieved by a direct mapping of kinematic and dynamic motion parameters to electronic sounds, resulting in continuous auditory and convergent audiovisual or audio-proprioceptive stimulus arrays. In sharp contrast to other approaches using acoustic information as error-feedback in motor learning settings, we try to generate additional movement information suitable for acceleration and enhancement of adequate sensorimotor representations and processible below the level of consciousness. In the experimental setting, participants were asked to learn a closed

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

    PubMed

    Peterson, Leif E; Kovyrshina, Tatiana

    2015-12-01

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

  16. Effects of Forgiveness of Perpetrators on Marital Adjustment for Survivors of Sexual Abuse.

    ERIC Educational Resources Information Center

    Holeman, Virginia Todd; Myers, Rita W.

    1998-01-01

    The effects of forgiveness on survivors' marital adjustment and the effects of childhood sexual abuse on forgiveness were examined. Self-report scales regarding abuse and forgiveness and demographic information were collected from clients (N=63). ANOVA produced significant main effects; forgiveness was negatively correlated with perceived…

  17. Prediction and estimation of effective population size.

    PubMed

    Wang, J; Santiago, E; Caballero, A

    2016-10-01

    Effective population size (Ne) is a key parameter in population genetics. It has important applications in evolutionary biology, conservation genetics and plant and animal breeding, because it measures the rates of genetic drift and inbreeding and affects the efficacy of systematic evolutionary forces, such as mutation, selection and migration. We review the developments in predictive equations and estimation methodologies of effective size. In the prediction part, we focus on the equations for populations with different modes of reproduction, for populations under selection for unlinked or linked loci and for the specific applications to conservation genetics. In the estimation part, we focus on methods developed for estimating the current or recent effective size from molecular marker or sequence data. We discuss some underdeveloped areas in predicting and estimating Ne for future research. PMID:27353047

  18. Prediction and estimation of effective population size.

    PubMed

    Wang, J; Santiago, E; Caballero, A

    2016-10-01

    Effective population size (Ne) is a key parameter in population genetics. It has important applications in evolutionary biology, conservation genetics and plant and animal breeding, because it measures the rates of genetic drift and inbreeding and affects the efficacy of systematic evolutionary forces, such as mutation, selection and migration. We review the developments in predictive equations and estimation methodologies of effective size. In the prediction part, we focus on the equations for populations with different modes of reproduction, for populations under selection for unlinked or linked loci and for the specific applications to conservation genetics. In the estimation part, we focus on methods developed for estimating the current or recent effective size from molecular marker or sequence data. We discuss some underdeveloped areas in predicting and estimating Ne for future research.

  19. Effects of Forecasts on the Revisions of Concurrent Seasonally Adjusted Data Using the X-11 Seasonal Adjustment Procedure.

    ERIC Educational Resources Information Center

    Bobbitt, Larry; Otto, Mark

    Three Autoregressive Integrated Moving Averages (ARIMA) forecast procedures for Census Bureau X-11 concurrent seasonal adjustment were empirically tested. Forty time series from three Census Bureau economic divisions (business, construction, and industry) were analyzed. Forecasts were obtained from fitted seasonal ARIMA models augmented with…

  20. Reverse-total shoulder arthroplasty cost-effectiveness: A quality-adjusted life years comparison with total hip arthroplasty

    PubMed Central

    Bachman, Daniel; Nyland, John; Krupp, Ryan

    2016-01-01

    AIM: To compare reverse-total shoulder arthroplasty (RSA) cost-effectiveness with total hip arthroplasty cost-effectiveness. METHODS: This study used a stochastic model and decision-making algorithm to compare the cost-effectiveness of RSA and total hip arthroplasty. Fifteen patients underwent pre-operative, and 3, 6, and 12 mo post-operative clinical examinations and Short Form-36 Health Survey completion. Short form-36 Health Survey subscale scores were converted to EuroQual Group Five Dimension Health Outcome scores and compared with historical data from age-matched patients who had undergone total hip arthroplasty. Quality-adjusted life year (QALY) improvements based on life expectancies were calculated. RESULTS: The cost/QALY was $3900 for total hip arthroplasty and $11100 for RSA. After adjusting the model to only include shoulder-specific physical function subscale items, the RSA QALY improved to 2.8 years, and its cost/QALY decreased to $8100. CONCLUSION: Based on industry accepted standards, cost/QALY estimates supported both RSA and total hip arthroplasty cost-effectiveness. Although total hip arthroplasty remains the quality of life improvement “gold standard” among arthroplasty procedures, cost/QALY estimates identified in this study support the growing use of RSA to improve patient quality of life. PMID:26925384

  1. Estimating Teacher Effectiveness from Two-Year Changes in Students' Test Scores

    ERIC Educational Resources Information Center

    Leigh, Andrew

    2010-01-01

    Using a dataset covering over 10,000 Australian school teachers and over 90,000 pupils, I estimate how effective teachers are in raising students' test scores. Since the exams are biennial, it is necessary to take account of the teacher's work in the intervening year. Even adjusting for measurement error, the teacher fixed effects are widely…

  2. Tailoring Feedback: Effective Feedback Should Be Adjusted Depending on the Needs of the Learner

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2011-01-01

    All students deserve effective feedback. General principles for effective feedback should be adjusted depending on the learner's needs. Feedback to struggling students should include focusing on the process, selecting only one or just a few points, giving self-referenced feedback to describe progress or capability, being very clear, and checking…

  3. Bicultural Effectiveness Training: A Treatment Intervention for Enhancing Intercultural Adjustment in Cuban American Families.

    ERIC Educational Resources Information Center

    Szapocznik, Jose; And Others

    1984-01-01

    By reducing culture conflict and acculturative stress, the Bicultural Effectiveness Training (BET) enhances adjustment in Cuban American families and reduces conduct disorders in adolescents. BET teaches family members that skills for effective functioning in different value contexts (cultural or otherwise) can be viewed as complementary and…

  4. Effects of aging and dual tasking on step adjustments to perturbations in visually cued walking.

    PubMed

    Mazaheri, Masood; Hoogkamer, Wouter; Potocanac, Zrinka; Verschueren, Sabine; Roerdink, Melvyn; Beek, Peter J; Peper, C E; Duysens, Jacques

    2015-12-01

    Making step adjustments is an essential component of walking. However, the ability to make step adjustments may be compromised when the walker's attentional capacity is limited. This study compared the effects of aging and dual tasking on step adjustments in response to stepping-target perturbations during visually cued treadmill walking. Fifteen older adults (69.4 ± 5.0 years; mean ± SD) and fifteen young adults (25.4 ± 3.0 years) walked at a speed of 3 km/h on a treadmill. Both groups performed visually cued step adjustments in response to unpredictable shifts of projected stepping targets in forward (FW), backward (BW) or sideward (SW) directions, at different levels of task difficulty [which increased as the available response distance (ARD) decreased], and with and without dual tasking (auditory Stroop task). In both groups, step adjustments were smaller than required. For FW and BW shifts, older adults undershot more under dual-task conditions. For these shifts, ARD affected the age groups differentially. For SW shifts, larger errors were found for older adults, dual tasking and the most difficult ARD. Stroop task performance did not differ between groups in all conditions. Older adults have more difficulty than young adults to make corrective step adjustments while walking, especially under dual-tasking conditions. Furthermore, they seemed to prioritize the cognitive task over the step adjustment task, a strategy that may pose aging populations at a greater fall risk. For comparable task difficulty, the older adults performed considerably worse than the young adults, indicating a decreased ability to adjust steps under time pressure.

  5. Effects of aging and dual tasking on step adjustments to perturbations in visually cued walking.

    PubMed

    Mazaheri, Masood; Hoogkamer, Wouter; Potocanac, Zrinka; Verschueren, Sabine; Roerdink, Melvyn; Beek, Peter J; Peper, C E; Duysens, Jacques

    2015-12-01

    Making step adjustments is an essential component of walking. However, the ability to make step adjustments may be compromised when the walker's attentional capacity is limited. This study compared the effects of aging and dual tasking on step adjustments in response to stepping-target perturbations during visually cued treadmill walking. Fifteen older adults (69.4 ± 5.0 years; mean ± SD) and fifteen young adults (25.4 ± 3.0 years) walked at a speed of 3 km/h on a treadmill. Both groups performed visually cued step adjustments in response to unpredictable shifts of projected stepping targets in forward (FW), backward (BW) or sideward (SW) directions, at different levels of task difficulty [which increased as the available response distance (ARD) decreased], and with and without dual tasking (auditory Stroop task). In both groups, step adjustments were smaller than required. For FW and BW shifts, older adults undershot more under dual-task conditions. For these shifts, ARD affected the age groups differentially. For SW shifts, larger errors were found for older adults, dual tasking and the most difficult ARD. Stroop task performance did not differ between groups in all conditions. Older adults have more difficulty than young adults to make corrective step adjustments while walking, especially under dual-tasking conditions. Furthermore, they seemed to prioritize the cognitive task over the step adjustment task, a strategy that may pose aging populations at a greater fall risk. For comparable task difficulty, the older adults performed considerably worse than the young adults, indicating a decreased ability to adjust steps under time pressure. PMID:26298043

  6. The effects of practice on speed of information processing using the Adjusting-Paced Serial Addition Test (Adjusting-PSAT) and the Computerized Tests of Information Processing (CTIP).

    PubMed

    Baird, B J; Tombaugh, Thomas N; Francis, M

    2007-01-01

    Three experiments were conducted to determine the effects of practice on the Adjusting-Paced Serial Addition Task (Adjusting-PSAT) (Tombaugh, 1999) and the Computerized Tests of Information Processing (CTIP) (Tombaugh & Rees, 2000). The Adjusting-PSAT is a computerized modification of the Paced Auditory Serial Addition Test (PASAT) (Gronwall, 1977) that makes the interval between digits contingent on the correctness of the response. This titration procedure permits a threshold value to be derived that represents the shortest presentation interval in which a person can process the digits to produce the correct sum. The CTIP consists of three reaction time tests that are progressively more difficult. Results showed that robust practice effects occurred with the Adjusting-PSAT, with the greatest increase in performance occurring on the first retest trial. Practice effects were equally prominent regardless of whether the first retest trial occurred 20A min, 1 week, or 3 months after the first administration. These gains were maintained for periods up to 6 months and were independent of modality of presentation (visual or auditory) and type of number list (easy or hard). In contrast to the findings with the Adjusting-PSAT, only minimal practice effects were observed with the CTIP. The major clinical implication of the study is that the high reliability coefficients for the CTIP, the lack of anxiety associated with its administration, and its insensitivity to variables such as numerical and verbal ability make the CTIP ideally suited for the serial evaluation of cognitive status. These characteristics also make the CTIP a viable alternative to the Adjusting-PSAT or PASAT for measuring speed of information processing. If the Adjusting-PSAT is administered repeatedly in clinical evaluations, a "dual baseline" or "run in" procedure should be used, with the second administration serving as the baseline measurement. PMID:17523883

  7. Sequence effects in estimating spatial location.

    PubMed

    Crawford, L Elizabeth; Duffy, Sean

    2010-10-01

    Three experiments provide evidence for a primacy effect in judgments of spatial location. Participants viewed and immediately estimated a series of spatial locations that were serially ordered from left to right or from right to left. In a subsequent block, they judged the rightmost, leftmost, and center of the distribution or were shown dots at those locations, which they then estimated from memory. Both judgments and memories were biased toward locations that had been presented earliest in the sequence. The findings indicate that participants incorporate not only geometric categories, but also aspects of their prior spatial experience, when estimating locations. The results mirror recent evidence for a primacy effect in nonspatial category induction, suggesting that this effect generalizes across domains.

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

    PubMed

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

    2014-07-01

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

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

    PubMed Central

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

    2014-01-01

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

  10. Regression equations for estimation of annual peak-streamflow frequency for undeveloped watersheds in Texas using an L-moment-based, PRESS-minimized, residual-adjusted approach

    USGS Publications Warehouse

    Asquith, William H.; Roussel, Meghan C.

    2009-01-01

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

  11. Motivating drivers to correctly adjust head restraints: assessing effectiveness of three different interventions.

    PubMed

    Fockler, S K; Vavrik, J; Kristiansen, L

    1998-11-01

    Three types of driver educational strategies were tested to determine the most effective approach for motivating drivers to adjust their head restraints to the correct vertical position: (1) a human interactive personal contact with a member of an ICBC-trained head restraint adjustment team, (2) a passive video presentation of the consequences of correct and incorrect head restraint adjustment, and (3) an interactive three-dimensional kinetic model showing the consequences of correct and incorrect head restraint adjustment. An experimental pretest-posttest control group design was used. A different educational treatment was used in each of three lanes of a vehicle emissions testing facility, with a fourth lane with no intervention serving as a control group. Observational and self-reported data were obtained from a total of 1,974 vehicles entering and exiting the facility. The human intervention led to significantly more drivers actually adjusting their head restraints immediately after the intervention than the passive video or interactive kinetic model approaches, which were both no different from the control group. The human intervention was recommended as the most effective and was implemented successfully on a limited basis during 3 months of 1995 and again during 3 months of 1996.

  12. [Structural adjustment, cultural adjustment?].

    PubMed

    Dujardin, B; Dujardin, M; Hermans, I

    2003-12-01

    Over the last two decades, multiple studies have been conducted and many articles published about Structural Adjustment Programmes (SAPs). These studies mainly describe the characteristics of SAPs and analyse their economic consequences as well as their effects upon a variety of sectors: health, education, agriculture and environment. However, very few focus on the sociological and cultural effects of SAPs. Following a summary of SAP's content and characteristics, the paper briefly discusses the historical course of SAPs and the different critiques which have been made. The cultural consequences of SAPs are introduced and are described on four different levels: political, community, familial, and individual. These levels are analysed through examples from the literature and individual testimonies from people in the Southern Hemisphere. The paper concludes that SAPs, alongside economic globalisation processes, are responsible for an acute breakdown of social and cultural structures in societies in the South. It should be a priority, not only to better understand the situation and its determining factors, but also to intervene and act with strategies that support and reinvest in the social and cultural sectors, which is vital in order to allow for individuals and communities in the South to strengthen their autonomy and identify.

  13. The Intertemporal Variability of Teacher Effect Estimates

    ERIC Educational Resources Information Center

    McCaffrey, Daniel F.; Sass, Tim R.; Lockwood, J. R.; Mihaly, Kata

    2009-01-01

    The utility of value-added estimates of teachers' effects on student test scores depends on whether they can distinguish between high- and low-productivity teachers and predict future teacher performance. This article studies the year-to-year variability in value-added measures for elementary and middle school mathematics teachers from five large…

  14. Three Essays on Estimating Causal Treatment Effects

    ERIC Educational Resources Information Center

    Deutsch, Jonah

    2013-01-01

    This dissertation is composed of three distinct chapters, each of which addresses issues of estimating treatment effects. The first chapter empirically tests the Value-Added (VA) model using school lotteries. The second chapter, co-authored with Michael Wood, considers properties of inverse probability weighting (IPW) in simple treatment effect…

  15. Enhancing Global Land Surface Hydrology Estimates from the NASA MERRA Reanalysis Using Precipitation Observations and Model Parameter Adjustments

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf; Koster, Randal; DeLannoy, Gabrielle; Forman, Barton; Liu, Qing; Mahanama, Sarith; Toure, Ally

    2011-01-01

    The Modern-Era Retrospective analysis for Research and Applications (MERRA) is a state-of-the-art reanalysis that provides. in addition to atmospheric fields. global estimates of soil moisture, latent heat flux. snow. and runoff for J 979-present. This study introduces a supplemental and improved set of land surface hydrological fields ('MERRA-Land') generated by replaying a revised version of the land component of the MERRA system. Specifically. the MERRA-Land estimates benefit from corrections to the precipitation forcing with the Global Precipitation Climatology Project pentad product (version 2.1) and from revised parameters in the rainfall interception model, changes that effectively correct for known limitations in the MERRA land surface meteorological forcings. The skill (defined as the correlation coefficient of the anomaly time series) in land surface hydrological fields from MERRA and MERRA-Land is assessed here against observations and compared to the skill of the state-of-the-art ERA-Interim reanalysis. MERRA-Land and ERA-Interim root zone soil moisture skills (against in situ observations at 85 US stations) are comparable and significantly greater than that of MERRA. Throughout the northern hemisphere, MERRA and MERRA-Land agree reasonably well with in situ snow depth measurements (from 583 stations) and with snow water equivalent from an independent analysis. Runoff skill (against naturalized stream flow observations from 15 basins in the western US) of MERRA and MERRA-Land is typically higher than that of ERA-Interim. With a few exceptions. the MERRA-Land data appear more accurate than the original MERRA estimates and are thus recommended for those interested in using '\\-tERRA output for land surface hydrological studies.

  16. "Effect of Anxiety Reduction on Children's School Performance and Social Adjustment": Correction to Wood (2006)

    ERIC Educational Resources Information Center

    Wood, Jeffrey J.

    2007-01-01

    Reports an error in "Effect of anxiety reduction on children's school performance and social adjustment" by Jeffrey Wood (Developmental Psychology, 2006[Mar], Vol 42[2], 345-349). The byline and author note should have included the author's middle initial, J. Thus, the byline and author note should refer to "Jeffrey J. Wood." The correction is…

  17. The Effects of Marital Conflict on Korean Children's Appraisal of Conflict and Psychological Adjustment

    ERIC Educational Resources Information Center

    Oh, Kyung Ja; Lee, Soojin; Park, Soo Hyun

    2011-01-01

    This study examined the effects of marital conflict on Korean children's psychological adjustment and appraisal of hypothetical marital conflict situations. Children between the ages of 10 and 12 were divided into "high-conflict" (n = 58) and "low-conflict" (n = 58) groups based on their self-reported degree of perceived interparental conflict in…

  18. The Effects Behavior Problems in Preschool Children Have on Their School Adjustment

    ERIC Educational Resources Information Center

    Yoleri, Sibel

    2013-01-01

    This research is conducted to examine the predictor effects the behavior problem level has on the school adjustment variable. With this objective, the sample research group consists of 136 children (having normal growth) between 5-6 years old attending preschools affiliated with the Ministry of National Education, and located in the city centre of…

  19. Parenting and Late Adolescent Emotional Adjustment: Mediating Effects of Discipline and Gender

    ERIC Educational Resources Information Center

    McKinney, Cliff; Milone, Mary Catherine; Renk, Kimberly

    2011-01-01

    Research suggests that parenting styles are related to the types of discipline parents utilize and that the coupling of parenting styles and discipline techniques are related to child outcomes. Although extant research examines the effects of parenting styles and discipline on child and early adolescent adjustment, less is known about adjustment…

  20. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on...

  1. School Climate Support for Behavioral and Psychological Adjustment: Testing the Mediating Effect of Social Competence

    ERIC Educational Resources Information Center

    Wang, Ming-Te

    2009-01-01

    The present study used an ecological framework to examine the relationships among adolescents' perceptions of school climate, social competence, and behavioral and psychological adjustment in the middle school years. This study improved upon prior studies by using "structural equation modeling" to investigate the hypothesized mediating effect of…

  2. Parenting and late adolescent emotional adjustment: mediating effects of discipline and gender.

    PubMed

    McKinney, Cliff; Milone, Mary Catherine; Renk, Kimberly

    2011-08-01

    Research suggests that parenting styles are related to the types of discipline parents utilize and that the coupling of parenting styles and discipline techniques are related to child outcomes. Although extant research examines the effects of parenting styles and discipline on child and early adolescent adjustment, less is known about adjustment in late adolescents, also described as emerging adults. Thus, the current study investigated the relationships among parenting styles (e.g., authoritative, authoritarian, permissive), discipline strategies (e.g., non-violent discipline, psychological aggression, physical assault), and emerging adult emotional adjustment (e.g., self-esteem, depression, and anxiety). The sample consisted of 526 participants ranging in age from 18 to 22 years. Results were analyzed with structural equation modeling and suggest that, although perceived parenting styles and discipline are both correlated with emerging adult emotional adjustment, perceived parenting is associated with emerging adult emotional adjustment for females but not males when examined simultaneously with perceived discipline. This finding demonstrates the importance of examining the direct and indirect relationships in the context of gender dyads. PMID:21479509

  3. [Effects of social support on the adjustment to extracurricular sports activities among junior high school students].

    PubMed

    Koshi, Ryoko; Sekizawa, Keiko

    2009-10-01

    This study examined the hypothesis that when students received and/or provided either support for skill improvement or support for interpersonal relations, their overall adjustment level in extracurricular activities would be higher than for students who received and/or provided neither support. Data were analyzed from 475 junior high school students (female 175, male 300) who were taking extracurricular sports activities, out of 743 research participants. The results were as follows. Students who received support mainly for skill improvement showed a statistically equivalent adjustment level as students who received support mainly for interpersonal relations. Students who received either support showed higher adjustment levels than students who received neither. Additionally, providing support showed the same results. The exchange of different types of social support showed equivalent effects on the adjustment level as the exchange of the same type of social support. These results suggest that even though the types of social support are different for skill improvement or interpersonal relations, the exchange of support positively contributes to junior high school students' adjustment level in extracurricular activities. PMID:19938660

  4. Parenting and late adolescent emotional adjustment: mediating effects of discipline and gender.

    PubMed

    McKinney, Cliff; Milone, Mary Catherine; Renk, Kimberly

    2011-08-01

    Research suggests that parenting styles are related to the types of discipline parents utilize and that the coupling of parenting styles and discipline techniques are related to child outcomes. Although extant research examines the effects of parenting styles and discipline on child and early adolescent adjustment, less is known about adjustment in late adolescents, also described as emerging adults. Thus, the current study investigated the relationships among parenting styles (e.g., authoritative, authoritarian, permissive), discipline strategies (e.g., non-violent discipline, psychological aggression, physical assault), and emerging adult emotional adjustment (e.g., self-esteem, depression, and anxiety). The sample consisted of 526 participants ranging in age from 18 to 22 years. Results were analyzed with structural equation modeling and suggest that, although perceived parenting styles and discipline are both correlated with emerging adult emotional adjustment, perceived parenting is associated with emerging adult emotional adjustment for females but not males when examined simultaneously with perceived discipline. This finding demonstrates the importance of examining the direct and indirect relationships in the context of gender dyads.

  5. Elucidation of a physiological adjustment effect in a forest environment: a pilot study.

    PubMed

    Song, Chorong; Ikei, Harumi; Miyazaki, Yoshifumi

    2015-04-01

    There is a significant positive relationship between exposure to forest environments and physical and mental health. However, there are individual differences within these responses, and this phenomenon has posed questions in various fields. Here, we show that the physiological effect of a forest environment can differ depending on a subject's initial values and that forests have a physiological adjustment effect close to an appropriate level. Subjects with high initial blood pressure and pulse rate showed a decrease in these values after walking in a forested area, whereas those with low initial values showed an increase. There was no physiological adjustment effect observed in an urban area; thus, these effects are specific to a forest environment.

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

    NASA Astrophysics Data System (ADS)

    Wang, Gaili; Liu, Liping; Ding, Yuanyuan

    2012-05-01

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

  7. [The effects of self-perception and attitudes to cultures on international students' feeling of adjustment].

    PubMed

    Hayashi, S

    1997-12-01

    Asian students of seven Japanese language schools participated, and data of 292 Chinese, Taiwanese, and Korean students were analyzed in this study. They were asked about (1) attitudes toward their own and other cultures, (2) high regard for their country and culture, (3) self-efficacy and social skills at the moment and when they were in their country, (4) aspired level of social skills in this country, and (5) feeling of adjustment to life in Japan. Main findings were as follows: (1) psychological factors had stronger effects on the feeling than demographic factors. Self-efficacy in particular had a strong effect. (2) Attitudes to own and other cultures were related to self-efficacy and the feeling. (3) Structural analysis revealed a difference in the feeling between students from socialist and capitalist regions. Based on the analysis, a causal model was proposed of psychological and demographic factors leading to feeling of adjustment, and Asian students' adjustment to life in Japan was discussed in terms of adjustment to their inner, psychological environment. PMID:9551537

  8. Double robust estimator of average causal treatment effect for censored medical cost data.

    PubMed

    Wang, Xuan; Beste, Lauren A; Maier, Marissa M; Zhou, Xiao-Hua

    2016-08-15

    In observational studies, estimation of average causal treatment effect on a patient's response should adjust for confounders that are associated with both treatment exposure and response. In addition, the response, such as medical cost, may have incomplete follow-up. In this article, a double robust estimator is proposed for average causal treatment effect for right censored medical cost data. The estimator is double robust in the sense that it remains consistent when either the model for the treatment assignment or the regression model for the response is correctly specified. Double robust estimators increase the likelihood the results will represent a valid inference. Asymptotic normality is obtained for the proposed estimator, and an estimator for the asymptotic variance is also derived. Simulation studies show good finite sample performance of the proposed estimator and a real data analysis using the proposed method is provided as illustration. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Double robust estimator of average causal treatment effect for censored medical cost data.

    PubMed

    Wang, Xuan; Beste, Lauren A; Maier, Marissa M; Zhou, Xiao-Hua

    2016-08-15

    In observational studies, estimation of average causal treatment effect on a patient's response should adjust for confounders that are associated with both treatment exposure and response. In addition, the response, such as medical cost, may have incomplete follow-up. In this article, a double robust estimator is proposed for average causal treatment effect for right censored medical cost data. The estimator is double robust in the sense that it remains consistent when either the model for the treatment assignment or the regression model for the response is correctly specified. Double robust estimators increase the likelihood the results will represent a valid inference. Asymptotic normality is obtained for the proposed estimator, and an estimator for the asymptotic variance is also derived. Simulation studies show good finite sample performance of the proposed estimator and a real data analysis using the proposed method is provided as illustration. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26818601

  10. The effect of somatic cell count data adjustment and interpretation, as outlined in European Union legislation, on herd eligibility to supply raw milk for processing of dairy products.

    PubMed

    More, S J; Clegg, T A; Lynch, P J; O'Grady, L

    2013-06-01

    Somatic cell count (SCC) limits are a key component of national and international regulation for milk quality. As yet, very limited work has been published on SCC regulatory standards, including on the effect of different approaches to SCC data adjustment and interpretation. This study examines the effect of SCC data adjustment and interpretation, as outlined in current European Union (EU) legislation, on herd eligibility to supply raw milk for processing of dairy products for human consumption, using Irish data for illustration. The study used Irish milk-recording data as a proxy for bulk tank SCC (BTSCC) data, to calculate an unadjusted monthly SCC value for each herd during each month of participation. Subsequently, 4 data adjustments were applied, as outlined in EU and national legislation: seasonal adjustment; 3-mo rolling geometric average, without accounting for a break in the supply; 3-mo rolling geometric average, after accounting for a break in the supply; and seasonal adjustment and 3-mo rolling geometric average combined, after accounting for a break in the supply. Analyses were conducted to examine the effect, during the period from 2004 to 2010, of data adjustment on the percentage of herds with herd SCC >400,000 cells/mL. In all, 4 interpretation scenarios, incorporating different data adjustment combinations, were used to estimate herd eligibility (compliant, under warning, or suspended, as defined by legislation) to supply raw milk for processing. The 4 methods of data adjustment each led to a sizable reduction (6.7, 5.0, 5.3, and 11.1 percentage points, respectively, compared with the unadjusted data) in the percentage of herds exceeding a herd SCC of 400,000 cells/mL. Herd eligibility varied by interpretation scenarios, in particular those incorporating seasonal adjustment. The study provides new perspectives on the effect of data adjustment on herd SCC and of interpretation scenarios on herd eligibility. The results provide an illustrative

  11. [Effect of economic structure adjustment on pollution emission: a case study of COD].

    PubMed

    Li, Ming-Sheng; Zhou, Lei; Chen, Yuan-Hang; Li, Qian; Zhang, Jian-Hui

    2014-08-01

    Economic structure adjustment is an important means to reduce the emissions of pollutants. For quantitative analysis of the effect of economic structure adjustment on the reduction of pollution emission, the country was divided into four sub-regions, eastern, northeastern, central and western, and the industry was divided into 39 sectors. Taking chemical oxygen demand (COD) as an example, the influences of regional structure and industry structure adjustment on total emission reduction and emission intensity were analyzed through building a model. The results showed that, in 2000-2010: (1) COD emissions in China were reduced from 1 445 x 10(4) t to 1 238 x 10(4) t, with a total emission of 14 950 x 10(4) t in 11 years, among which the emissions from eastern area occupied the largest proportion, accounting for 35.6%. (2) In the industrial COD emissions, emission from paper and paper products was the largest, accounting for 35.8% of the industrial COD emissions. (3) The economic structure changes in the four areas reduced the COD emissions by 420 x 10(4) t, resulting in a decrease of 1.29% in COD emission intensity. (4) Industrial internal structure changes reduced the COD emissions by 533 x 10(4) t, leading to a decrease of 3.1% in COD emission intensity. The research results have certain reference value in guiding the Chinese economic structure adjustment and achieving the targets of energy-saving and emission reduction.

  12. Effects of Biofreeze and chiropractic adjustments on acute low back pain: a pilot study☆

    PubMed Central

    Zhang, John; Enix, Dennis; Snyder, Brian; Giggey, Kristan; Tepe, Rodger

    2008-01-01

    Abstract Objective This randomized controlled study was designed to determine the pain-relieving effect of Biofreeze (Performance Health Inc., Export, PA) body surface application and chiropractic adjustments on subjects with acute low back pain (LBP). Methods The data were collected at the baseline, 2 weeks after treatment, and 4 weeks after treatment for final analyses. Diversified manual adjustments were provided by licensed chiropractors twice a week for 4 weeks to both control and experimental groups. Biofreeze was applied to the lower back area 3 times a day for 4 weeks in the experimental group. Outcome assessments included visual analog scale, Roland Morris Disability Questionnaire, heart rate variability for stress, and electromyography for low back muscle activity. Results A total of 36 subjects were recruited in the study (25 male). The average age was 34 years. Significant pain reduction was found after each week of treatment in the experimental group (P < .05). The Roland Morris Disability Questionnaire did not show significant changes in both groups. There were no significant differences for pain reduction in the control group. Heart rate variability analysis showed no significant change (P > .05) in the experimental group after 4 weeks of Biofreeze and chiropractic adjustments. There were no statistically significant changes in the electromyography readings between the 2 groups. Conclusion Biofreeze combined with chiropractic adjustment showed significant reduction in LBP. PMID:19674721

  13. Effects of emotional support-focused nursing interventions on the psychosocial adjustment of breast cancer patients.

    PubMed

    Gümüs, Aysun Babacan; Cam, Olcay

    2008-01-01

    The purpose was to examine the effect of emotional support-focused nursing interventions on the psychosocial adjustment of breast cancer patients. The research was conducted in the Radiation Oncology Department of Ege University Medical Faculty Hospital and at Talay Aktas Oncology Hospital in Turkey. There were 30 newly diagnosed breast cancer patients included in the sample. Emotional support-focused nursing interventions were administered in seven sessions individually with each patient. A total of 210 hours of meetings with the patients were conducted. Data were collected by administering a pre-test and post-test in two phases with the patients using a Descriptive Information Form and the Psychosocial Adjustment to Illness Scale - Self Report (PAIS-SR). The patients mean age was 44.5 (SD=6.38) years and the mean duration of illness was 6.46 (SD=1.99) months. In the comparison of the PAIS-SR pretest and post-test mean scores it was determined that there was a significant increase in patients adaptation to health care orientation (p=0.001), domestic environment (p<0.01), sexual relationships (p<0.05), extended family relationships (p<0.001) and social environment (p<0.001), and a significant decrease in psychological distress (p<0.001). However, there was no change in patients vocational adjustment (p<0.05). According to these findings emotional support-focused nursing interventions had a part in increasing patients psychosocial adjustment. PMID:19256761

  14. The effects of coping on adjustment: Re-examining the goodness of fit model of coping effectiveness.

    PubMed

    Masel, C N; Terry, D J; Gribble, M

    1996-01-01

    Abstract The primary aim of the present study was to examine the extent to which the effects of coping on adjustment are moderated by levels of event controllability. Specifically, the research tested two revisions to the goodness of fit model of coping effectiveness. First, it was hypothesized that the effects of problem management coping (but not problem appraisal coping) would be moderated by levels of event controllability. Second, it was hypothesized that the effects of emotion-focused coping would be moderated by event controllability, but only in the acute phase of a stressful encounter. To test these predictions, a longitudinal study was undertaken (185 undergraduate students participated in all three stages of the research). Measures of initial adjustment (low depression and coping efficacy) were obtained at Time 1. Four weeks later (Time 2), coping responses to a current or a recent stressor were assessed. Based on subjects' descriptions of the event, objective and subjective measures of event controllability were also obtained. Measures of concurrent and subsequent adjustment were obtained at Times 2 and 3 (two weeks later), respectively. There was only weak support for the goodness of fit model of coping effectiveness. The beneficial effects of a high proportion of problem management coping (relative to total coping efforts) on Time 3 perceptions of coping efficacy were more evident in high control than in low control situations. Other results of the research revealed that, irrespective of the controllability of the event, problem appraisal coping strategies and emotion-focused strategies (escapism and self-denigration) were associated with high and low levels of concurrent adjustment, respectively. The effects of these coping responses on subsequent adjustment were mediated through concurrent levels of adjustment.

  15. Effects of anchoring and adjustment in the evaluation of product pricing.

    PubMed

    Elaad, Eitan; Sayag, Neta; Ezer, Aliya

    2010-08-01

    Anchoring and adjustment comprise a heuristic that creates expectations. Two types of anchors were applied on participants' evaluation of products: the price reference of the product (maximum, minimum, or no price reference) and the context in which the products were evaluated (the prestige of the shopping center). Results showed that both factors anchored evaluations of products' value. Context effects were explained by the different expectations of visitors in prestigious (looking for quality) and less prestigious (seeking a bargain) centers.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  17. Effects of site-specific level adjustments on speech recognition with cochlear implants

    PubMed Central

    Zhou, Ning; Pfingst, Bryan E.

    2013-01-01

    ) required for 50% correct speech recognition, were evaluated for these MAPs using CUNY sentences. The site-specific level-adjusted MAPs were compared to the globally level-adjusted MAP and the MAP without level adjustment. The effects on speech recognition of adjusting the minimal stimulation level settings on the 5 poorest stimulation sites were also compared with effects of removing these sites from the speech-processor MAP. Results The 5% level increase on the 5 electrodes with the worst MDTs resulted in an improvement in the group-mean SRT of 2.36 dB SNR relative to the MAP without level adjustment. The magnitude of level increase that resulted in the greatest SRT improvement for individuals varied across ears. MDTs measured at 20% DR significantly improved on the poor sites after the level adjustment that resulted in the best SRT for that ear was applied. Increasing the minimal stimulation levels on all stimulation sites or removing sites selected for rehabilitation, the parsimonious approaches, did not improve speech reception thresholds. Conclusions The site-specific adjustments of the T level settings improved modulation sensitivity at low levels and significantly improved subjects’ speech reception thresholds. Thus, this site-rehabilitation strategy was an effective alternative to site-selection strategies for improving speech recognition in cochlear implant users. PMID:24225651

  18. Baseline adjustment and change revisited: effect of smoking on change in periodontal status following periodontal therapy.

    PubMed

    Preus, Hans R; Sandvik, Leiv; Gjermo, Per; Baelum, Vibeke

    2014-04-01

    Smokers have frequently been reported to have more severe periodontitis, to respond less favorably to periodontal therapy, and to show elevated rate of recurrence compared with non-smokers. The aims of this study was to compare the results of baseline-adjusted and -unadjusted analyses when assessing the effect of smoking on change in periodontal status following therapy and to discuss the methodological issues involved. This is a secondary analysis of data from 180 periodontitis patients enrolled in a randomized controlled clinical intervention trial. Information on smoking habits was elicited from the participants before, and 12 months after, therapy. The clinical parameters analyzed were probing pocket depth and clinical attachment level, using both simple analysis of change (SAC) and analysis of covariance (ancova), adjusting for age, gender, and treatment group. The current smokers presented with more severe periodontitis at baseline than did former and never smokers. Results of the SAC indicated that the current smokers benefitted more from treatment than did former or never smokers, whereas the results of the baseline-adjusted ancova indicated no such differences. Both sets of results are likely to be biased with respect to valid conclusions regarding the 'causal' effect of smoking. Possible sources of bias are discussed.

  19. Self-Reported Adolescent Behavioral Adjustment: Effects of Prenatal Cocaine Exposure

    PubMed Central

    Min, Meeyoung O.; Minnes, Sonia; Yoon, Susan; Short, Elizabeth J.; Singer, Lynn T.

    2014-01-01

    Purpose To assess the direct effects of prenatal cocaine exposure (PCE) on adolescent internalizing, externalizing and attention problems, controlling for confounding drug and environmental factors. Method At 12 and 15 years of age, 371 adolescents (189 PCE, 182 non-cocaine exposed (NCE)), primarily African-American and of low socioeconomic status, participating in a longitudinal, prospective study from birth were assessed for behavioral adjustment using the Youth Self-Report (YSR). Results Longitudinal mixed model analyses indicated that PCE was associated with greater externalizing behavioral problems at ages 12 and 15 and more attention problems at age 15, after controlling for confounders. PCE effects were not found for internalizing behaviors. PCE adolescents in adoptive/foster care reported more externalizing and attention problems than PCE adolescents in biological mother/relative care at age 12 or NCE adolescents at both ages. No PCE by gender interaction was found. Prenatal marijuana exposure, home environment, parental attachment and monitoring, family conflict, and violence exposure were also significant predictors of adolescent behavioral adjustment. Conclusions Prenatal cocaine exposure is a risk factor for poor behavioral adjustment in adolescence. PMID:24581794

  20. The effects of sibling relationships on social adjustment among Japanese twins compared with singletons.

    PubMed

    Nozaki, Mari; Fujisawa, Keiko K; Ando, Juko; Hasegawa, Toshikazu

    2012-12-01

    This study examined the link between sibling relationships and children's social adjustment by comparing twin siblings and siblings with different ages (singleton siblings}, and clarified the role of reciprocity in sibling relationships on children's social development. Mothers of 58 monozygotic twin pairs, 48 dizygotic twin pairs, and 86 singleton sibling pairs reported their children's sibling relationships and social adjustment.This study showed that the effects of sibling relationships on the prosocial behaviors and conduct problems of each child are stronger for twins than for singleton siblings. Moreover, positivity toward one's sibling increased peer problems only among monozygotic twins. The opposite tendency was present among dizygotic twins and singleton siblings. This study suggests the importance for children's social development of having many interactions with siblings and establishing reciprocity in sibling relationships. Moreover, our results suggest that the quality of sibling relationships among monozygotic twins may be different from those among dizygotic twins and singleton siblings.

  1. Cyclostrophic adjustment in swirling gas flows and the Ranque-Hilsch vortex tube effect

    SciTech Connect

    Kalashnik, M. V. Visheratin, K. N.

    2008-04-15

    A theoretical analysis of cyclostrophic adjustment is presented; i.e., adjustment to balance between pressure gradient and centrifugal force in axisymmetric flow of an inviscid gas is examined. The solution to the problem is represented as the sum of a time-independent (balanced) and time-dependent (wave) components. It is shown that the wave component of the flow in an unbounded domain decays with time, and the corresponding solution reduces to the balanced component. In a bounded domain, the balanced flow component exists against the background of undamped acoustic waves. It is found that the balanced flow is thermally stratified at Mach numbers close to unity, with a substantial decrease in gas temperature (to between -50 and -100 deg. C) in the axial region. This finding, combined with the results of special experiments, is used to explain the Ranque-Hilsch vortex tube effect.

  2. Cyclostrophic adjustment in swirling gas flows and the Ranque-Hilsch vortex tube effect

    NASA Astrophysics Data System (ADS)

    Kalashnik, M. V.; Visheratin, K. N.

    2008-04-01

    A theoretical analysis of cyclostrophic adjustment is presented; i.e., adjustment to balance between pressure gradient and centrifugal force in axisymmetric flow of an inviscid gas is examined. The solution to the problem is represented as the sum of a time-independent (balanced) and time-dependent (wave) components. It is shown that the wave component of the flow in an unbounded domain decays with time, and the corresponding solution reduces to the balanced component. In a bounded domain, the balanced flow component exists against the background of undamped acoustic waves. It is found that the balanced flow is thermally stratified at Mach numbers close to unity, with a substantial decrease in gas temperature (to between -50 and -100°C) in the axial region. This finding, combined with the results of special experiments, is used to explain the Ranque-Hilsch vortex tube effect.

  3. Effective System for Automatic Bundle Block Adjustment and Ortho Image Generation from Multi Sensor Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Akilan, A.; Nagasubramanian, V.; Chaudhry, A.; Reddy, D. Rajesh; Sudheer Reddy, D.; Usha Devi, R.; Tirupati, T.; Radhadevi, P. V.; Varadan, G.

    2014-11-01

    Block Adjustment is a technique for large area mapping for images obtained from different remote sensingsatellites.The challenge in this process is to handle huge number of satellite imageries from different sources with different resolution and accuracies at the system level. This paper explains a system with various tools and techniques to effectively handle the end-to-end chain in large area mapping and production with good level of automation and the provisions for intuitive analysis of final results in 3D and 2D environment. In addition, the interface for using open source ortho and DEM references viz., ETM, SRTM etc. and displaying ESRI shapes for the image foot-prints are explained. Rigorous theory, mathematical modelling, workflow automation and sophisticated software engineering tools are included to ensure high photogrammetric accuracy and productivity. Major building blocks like Georeferencing, Geo-capturing and Geo-Modelling tools included in the block adjustment solution are explained in this paper. To provide optimal bundle block adjustment solution with high precision results, the system has been optimized in many stages to exploit the full utilization of hardware resources. The robustness of the system is ensured by handling failure in automatic procedure and saving the process state in every stage for subsequent restoration from the point of interruption. The results obtained from various stages of the system are presented in the paper.

  4. What is the effect of adjusting epirubicin doses for body surface area?

    PubMed Central

    Dobbs, N. A.; Twelves, C. J.

    1998-01-01

    Doses of cytotoxic drugs are routinely adjusted according to body surface area. We have evaluated this practice in 32 women with advanced breast cancer treated with single-agent epirubicin 12.5-120 mg m(-2). Epirubicin and its metabolites were measured by high-performance liquid chromatography (HPLC). Unadjusted plasma clearance was calculated from dose in mg, and adjusted clearance from dose in mg m(-2). Unadjusted clearance did not correlate with surface area, height, weight, per cent ideal body weight or body mass index. There was no difference in the coefficient of variation (CV) of adjusted and unadjusted clearance (39.4% and 37.7% respectively). The AUC that would have resulted from giving an unadjusted dose was calculated. This predicted AUC was accurate, unbiased and had the same CV as the actual AUC. Similarly, in 11 patients an analysis of actual and predicted neutropenia confirmed that unadjusted dosing would have had no significant effect on the pattern of myelosuppression. Normalization of epirubicin dosage according to surface area appears not to reduce either pharmacokinetic or pharmacodynamic variability. PMID:9744507

  5. Internet for the internationals: effects of internet use motivations on international students' college adjustment.

    PubMed

    Lee, Eun-Ju; Lee, Lu; Jang, Jeongwoo

    2011-01-01

    Drawing upon the uses and gratifications approach, the current study examined how international students' Internet use motivations affect their academic, social, and emotional adjustments in the new environment. A total of 166 Chinese students studying in Korea participated in a web-based survey. First, a factor analysis identified four distinct motivations for Internet use: homeland orientation (to stay connected to the home country), local information seeking (to learn about the host society), local social interaction (to form interpersonal relationships locally), and entertainment. After controlling for the effects of sociodemographic variables (i.e., gender, year at school, length of residence, Korean language proficiency) and personality traits (i.e., extraversion, openness to experience, neuroticism), Internet use motivations were found to be significant predictors of international students' social and emotional adjustments. Specifically, those seeking to build a local social network through the Internet reported greater satisfaction with their social life, whereas homeland orientation was associated with poorer emotional adaptation. Various Internet activities, such as e-mail, blogging, and instant messaging, were not significantly related to college adjustments, suggesting the multi-functionality of Internet-based communication channels.

  6. Internet for the internationals: effects of internet use motivations on international students' college adjustment.

    PubMed

    Lee, Eun-Ju; Lee, Lu; Jang, Jeongwoo

    2011-01-01

    Drawing upon the uses and gratifications approach, the current study examined how international students' Internet use motivations affect their academic, social, and emotional adjustments in the new environment. A total of 166 Chinese students studying in Korea participated in a web-based survey. First, a factor analysis identified four distinct motivations for Internet use: homeland orientation (to stay connected to the home country), local information seeking (to learn about the host society), local social interaction (to form interpersonal relationships locally), and entertainment. After controlling for the effects of sociodemographic variables (i.e., gender, year at school, length of residence, Korean language proficiency) and personality traits (i.e., extraversion, openness to experience, neuroticism), Internet use motivations were found to be significant predictors of international students' social and emotional adjustments. Specifically, those seeking to build a local social network through the Internet reported greater satisfaction with their social life, whereas homeland orientation was associated with poorer emotional adaptation. Various Internet activities, such as e-mail, blogging, and instant messaging, were not significantly related to college adjustments, suggesting the multi-functionality of Internet-based communication channels. PMID:21117984

  7. Academic self-concept in high school: predictors and effects on adjustment in higher education.

    PubMed

    Wouters, Sofie; Germeijs, Veerle; Colpin, Hilde; Verschueren, Karine

    2011-12-01

    Academic self-concept is considered a relevant psychological construct influencing many educational outcomes directly or indirectly. Therefore, the major focus of the current study is on the predictors and effects of academic self-concept in late adolescence. First, we studied the simultaneous effects of individual, class-average and school-average achievement (i.e., assessed by school grades) on academic self-concept in the final year of high school, thereby replicating and extending previous research on the big-fish-little-pond effect model. Second, the predictive value of high school academic self-concept for academic adjustment and success in the first year of higher education was examined. The sample comprised 536 twelfth grade students (44% boys) recruited from 24 schools (67 classes) that were representative with regard to geographical region and educational network in Flanders. Structural equation modeling showed that, when examining the joint contribution of school- and class-average achievement, only class-average achievement was significantly and negatively associated with academic self-concept. Furthermore, a significant effect of academic self-concept in high school on academic adjustment and success in higher education (in addition to any effects of high school academic achievement) was found. These results highlight the importance of considering academic self-concept in educational research and policy.

  8. Teachers and Their International Relocation: The Effect of Self-Esteem and Pay Satisfaction on Adjustment and Outcome Variables

    ERIC Educational Resources Information Center

    Richardson, Warnie; von Kirchenheim, Clement; Richardson, Carole

    2006-01-01

    This is the second of two papers investigating the adjustment process in a designated group of expatriates, (teachers), who have severed ties with their home country and employer. In the first paper we examined the effect of self-efficacy and flexibility within this adjustment process, revealing the significance of self-efficacy but failing to…

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  10. Posttraumatic growth moderates the effects of posttraumatic stress symptoms on adjustment and positive affective reactions in digestive system cancer patients.

    PubMed

    Ben-Zur, Hasida; Cohen, Miri; Gouzman, Julia

    2015-01-01

    The study aims were twofold: (1) To investigate the associations of posttraumatic stress symptoms (PTSS) and posttraumatic growth (PTG) with adjustment and affective reactions of digestive system cancer patients and (2) To assess the moderating effects of PTG on the associations of PTSS with adjustment and affective reactions. The sample consisted of 200 respondents 1-4 years following diagnosis and treatment for digestive system cancer. Participants completed questionnaires assessing PTSS, PTG, adjustment, positive affect (PA), and negative affect (NA). The results showed that PTG was positively associated with adjustment and PA, while PTSS was negatively associated with these outcomes and positively associated with NA. Moderation effects of PTG were also observed: The negative associations between PTSS and adjustment or PA were weaker under high levels than under low levels of PTG. It was concluded that PTG is important both as a contributor to better adjustment and PA, as well as a moderator of the detrimental effects of PTSS on adjustment and PA following recovery from cancer. Thus, when developing post-cancer intervention programs, PTG should be viewed as a factor to be encouraged and nurtured for the benefit of cancer patients' adjustment and their long-term well-being.

  11. The effect of case-mix adjustment on admission-based reimbursement.

    PubMed Central

    Kinzer, D; Warner, M

    1983-01-01

    This paper addresses two questions: (1) Does adjusting for case mix have any effect on prospective admission-based reimbursement? and (2) How does the way in which case type is defined (DRG, ICD9CM, Age, etc) affect reimbursement systems? Data from 20 Maryland hospitals provided the basis for analysis, and the results illustrate how hospital reimbursement is affected under alternative definitions of case type (including no case type), showing highly significant variation. Implications for cost control and existing and proposed prospective reimbursement systems are discussed. Images Figure 5 PMID:6409840

  12. Changes in social adjustment with cognitive processing therapy: effects of treatment and association with PTSD symptom change.

    PubMed

    Monson, Candice M; Macdonald, Alexandra; Vorstenbosch, Valerie; Shnaider, Philippe; Goldstein, Elizabeth S R; Ferrier-Auerbach, Amanda G; Mocciola, Katharine E

    2012-10-01

    The current study sought to determine if different spheres of social adjustment, social and leisure, family, and work and income improved immediately following a course of cognitive processing therapy (CPT) when compared with those on a waiting list in a sample of 46 U.S. veterans diagnosed with posttraumatic stress disorder (PTSD). We also sought to determine whether changes in different PTSD symptom clusters were associated with changes in these spheres of social adjustment. Overall social adjustment, extended family relationships, and housework completion significantly improved in the CPT versus waiting-list condition, η(2) = .08 to .11. Hierarchical multiple regression analyses revealed that improvements in total clinician-rated PTSD symptoms were associated with improvements in overall social and housework adjustment. When changes in reexperiencing, avoidance, emotional numbing, and hyperarousal were all in the model accounting for changes in total social adjustment, improvements in emotional numbing symptoms were associated with improvements in overall social, extended family, and housework adjustment (β = .38 to .55). In addition, improvements in avoidance symptoms were associated with improvements in housework adjustment (β = .30), but associated with declines in extended family adjustment (β = -.34). Results suggest that it is important to consider the extent to which PTSD treatments effectively reduce specific types of symptoms, particularly emotional numbing and avoidance, to generally improve social adjustment.

  13. Study on quantile estimates of extreme precipitation and their spatiotemporal consistency adjustment over the Huaihe River basin

    NASA Astrophysics Data System (ADS)

    Shao, Yuehong; Wu, Junmei; Li, Min

    2016-09-01

    The quantile estimates and spatiotemporal consistency of extreme precipitation are studied by regional linear frequency analysis for Huaihe River basin in China. Firstly, the study area can be categorized into six homogeneous regions by using cluster analysis, heterogeneity measure, and discordancy measure. In the next step, we determine the optimum distribution for each homogeneous region by using two criteria of Monte Carlo simulations and the root-mean-square error (RMSE) of the sample L-moments. A diagram of L-moments ratio is used to further judge and validate the optimum distribution. The generalized extreme value (GEV), generalized normal (GNO), and generalized logistic (GLO) for 24-h duration are determined to be the more appropriate distribution based on the two criteria, L-moments ratio plot, and the tail thickness of curve in adjacent regions. A summary assessment can provide the more reasonable distribution, which avoids arbitrary results from single test. An important practical element of this study that was missing from previous works is the quantile spatiotemporal consistency analysis, which helps identify non-monotonicity among quantiles at different durations and reduces the gradient of estimates in the adjacent regions. Abnormality and spatial discontinuation can be removed by distributing the surplus of the ratio and twice different interpolation. A complete set of spatiotemporal consistent quantile estimates for various duration (24 h, 3 days, 5 days, and 7 days) and return periods (from 2 to 1000 years) can be obtained by using the abovementioned method in the study area, which are in the agreement with the observed precipitation extremes. It will provide important basis for hydrometeorological research, which is of significant scientific and practical merit.

  14. Estimate of overdiagnosis of breast cancer due to mammography after adjustment for lead time. A service screening study in Italy

    PubMed Central

    Paci, Eugenio; Miccinesi, Guido; Puliti, Donella; Baldazzi, Paola; De Lisi, Vincenzo; Falcini, Fabio; Cirilli, Claudia; Ferretti, Stefano; Mangone, Lucia; Finarelli, Alba Carola; Rosso, Stefano; Segnan, Nereo; Stracci, Fabrizio; Traina, Adele; Tumino, Rosario; Zorzi, Manuel

    2006-01-01

    Introduction Excess of incidence rates is the expected consequence of service screening. The aim of this paper is to estimate the quota attributable to overdiagnosis in the breast cancer screening programmes in Northern and Central Italy. Methods All patients with breast cancer diagnosed between 50 and 74 years who were resident in screening areas in the six years before and five years after the start of the screening programme were included. We calculated a corrected-for-lead-time number of observed cases for each calendar year. The number of observed incident cases was reduced by the number of screen-detected cases in that year and incremented by the estimated number of screen-detected cases that would have arisen clinically in that year. Results In total we included 13,519 and 13,999 breast cancer cases diagnosed in the pre-screening and screening years, respectively. In total, the excess ratio of observed to predicted in situ and invasive cases was 36.2%. After correction for lead time the excess ratio was 4.6% (95% confidence interval 2 to 7%) and for invasive cases only it was 3.2% (95% confidence interval 1 to 6%). Conclusion The remaining excess of cancers after individual correction for lead time was lower than 5%. PMID:17147789

  15. Effects of Timing of Adversity on Adolescent and Young Adult Adjustment

    ERIC Educational Resources Information Center

    Kiff, Cara J.; Cortes, Rebecca C.; Lengua, Liliana J.; Kosterman, Rick; Hawkins, J. David; Mason, W. Alex

    2012-01-01

    Exposure to adversity during childhood and adolescence predicts adjustment across development. Furthermore, adolescent adjustment problems persist into young adulthood. This study examined relations of contextual adversity with concurrent adolescent adjustment and prospective mental health and health outcomes in young adulthood. A longitudinal…

  16. Effects of Overlapping Generations on Linkage Disequilibrium Estimates of Effective Population Size

    PubMed Central

    Waples, Robin S.; Antao, Tiago; Luikart, Gordon

    2014-01-01

    Use of single-sample genetic methods to estimate effective population size has skyrocketed in recent years. Although the underlying models assume discrete generations, they are widely applied to age-structured species. We simulated genetic data for 21 iteroparous animal and plant species to evaluate two untested hypotheses regarding performance of the single-sample method based on linkage disequilibrium (LD): (1) estimates based on single-cohort samples reflect the effective number of breeders in one reproductive cycle (Nb), and (2) mixed-age samples reflect the effective size per generation (Ne). We calculated true Ne and Nb, using the model species’ vital rates, and verified these with individual-based simulations. We show that single-cohort samples should be equally influenced by Nb and Ne and confirm this with simulated results: N^b was a linear (r2 = 0.98) function of the harmonic mean of Ne and Nb. We provide a quantitative bias correction for raw N^b based on the ratio Nb/Ne, which can be estimated from two or three simple life history traits. Bias-adjusted estimates were within 5% of true Nb for all 21 study species and proved robust when challenged with new data. Mixed-age adult samples produced downwardly biased estimates in all species, which we attribute to a two-locus Wahlund effect (mixture LD) caused by combining parents from different cohorts in a single sample. Results from this study will facilitate interpretation of rapidly accumulating genetic estimates in terms of both Ne (which influences long-term evolutionary processes) and Nb (which is more important for understanding eco-evolutionary dynamics and mating systems). PMID:24717176

  17. Effects of age, weight, and fat slaughter end points on estimates of breed and retained heterosis effects for carcass traits.

    PubMed

    Ríos-Utrera, A; Cundiff, L V; Gregory, K E; Koch, R M; Dikeman, M E; Koohmaraie, M; Van Vleck, L D

    2006-01-01

    The influence of different levels of adjusted fat thickness (AFT) and HCW slaughter end points (covariates) on estimates of breed and retained heterosis effects was studied for 14 carcass traits from serially slaughtered purebred and composite steers from the US Meat Animal Research Center (MARC). Contrasts among breed solutions were estimated at 0.7, 1.1, and 1.5 cm of AFT, and at 295.1, 340.5, and 385.9 kg of HCW. For constant slaughter age, contrasts were adjusted to the overall mean (432.5 d). Breed effects for Red Poll, Hereford, Limousin, Braunvieh, Pinzgauer, Gelbvieh, Simmental, Charolais, MARC I, MARC II, and MARC III were estimated as deviations from Angus. In addition, purebreds were pooled into 3 groups based on lean-to-fat ratio, and then differences were estimated among groups. Retention of combined individual and maternal heterosis was estimated for each composite. Mean retained heterosis for the 3 composites also was estimated. Breed rankings and expression of heterosis varied within and among end points. For example, Charolais had greater (P < 0.05) dressing percentages than Angus at the 2 largest levels of AFT and smaller (P < 0.01) percentages at the 2 largest levels of HCW, whereas the 2 breeds did not differ (P > or = 0.05) at a constant age. The MARC III composite produced 9.7 kg more (P < 0.01) fat than Angus at AFT of 0.7 cm, but 7.9 kg less (P < 0.05) at AFT of 1.5 cm. For MARC III, the estimate of retained heterosis for HCW was significant (P < 0.05) at the lowest level of AFT, but at the intermediate and greatest levels estimates were nil. The pattern was the same for MARC I and MARC III for LM area. Adjustment for age resulted in near zero estimates of retained heterosis for AFT, and similarly, adjustment for HCW resulted in nil estimates of retained heterosis for LM area. For actual retail product as a percentage of HCW, the estimate of retained heterosis for MARC III was negative (-1.27%; P < 0.05) at 0.7 cm but was significantly

  18. Effects of age, weight, and fat slaughter end points on estimates of breed and retained heterosis effects for carcass traits.

    PubMed

    Ríos-Utrera, A; Cundiff, L V; Gregory, K E; Koch, R M; Dikeman, M E; Koohmaraie, M; Van Vleck, L D

    2006-01-01

    The influence of different levels of adjusted fat thickness (AFT) and HCW slaughter end points (covariates) on estimates of breed and retained heterosis effects was studied for 14 carcass traits from serially slaughtered purebred and composite steers from the US Meat Animal Research Center (MARC). Contrasts among breed solutions were estimated at 0.7, 1.1, and 1.5 cm of AFT, and at 295.1, 340.5, and 385.9 kg of HCW. For constant slaughter age, contrasts were adjusted to the overall mean (432.5 d). Breed effects for Red Poll, Hereford, Limousin, Braunvieh, Pinzgauer, Gelbvieh, Simmental, Charolais, MARC I, MARC II, and MARC III were estimated as deviations from Angus. In addition, purebreds were pooled into 3 groups based on lean-to-fat ratio, and then differences were estimated among groups. Retention of combined individual and maternal heterosis was estimated for each composite. Mean retained heterosis for the 3 composites also was estimated. Breed rankings and expression of heterosis varied within and among end points. For example, Charolais had greater (P < 0.05) dressing percentages than Angus at the 2 largest levels of AFT and smaller (P < 0.01) percentages at the 2 largest levels of HCW, whereas the 2 breeds did not differ (P > or = 0.05) at a constant age. The MARC III composite produced 9.7 kg more (P < 0.01) fat than Angus at AFT of 0.7 cm, but 7.9 kg less (P < 0.05) at AFT of 1.5 cm. For MARC III, the estimate of retained heterosis for HCW was significant (P < 0.05) at the lowest level of AFT, but at the intermediate and greatest levels estimates were nil. The pattern was the same for MARC I and MARC III for LM area. Adjustment for age resulted in near zero estimates of retained heterosis for AFT, and similarly, adjustment for HCW resulted in nil estimates of retained heterosis for LM area. For actual retail product as a percentage of HCW, the estimate of retained heterosis for MARC III was negative (-1.27%; P < 0.05) at 0.7 cm but was significantly

  19. Burden of Six Healthcare-Associated Infections on European Population Health: Estimating Incidence-Based Disability-Adjusted Life Years through a Population Prevalence-Based Modelling Study

    PubMed Central

    Eckmanns, Tim; Abu Sin, Muna; Ducomble, Tanja; Harder, Thomas; Sixtensson, Madlen; Velasco, Edward; Weiß, Bettina; Kramarz, Piotr; Monnet, Dominique L.; Kretzschmar, Mirjam E.; Suetens, Carl

    2016-01-01

    Background Estimating the burden of healthcare-associated infections (HAIs) compared to other communicable diseases is an ongoing challenge given the need for good quality data on the incidence of these infections and the involved comorbidities. Based on the methodology of the Burden of Communicable Diseases in Europe (BCoDE) project and 2011–2012 data from the European Centre for Disease Prevention and Control (ECDC) point prevalence survey (PPS) of HAIs and antimicrobial use in European acute care hospitals, we estimated the burden of six common HAIs. Methods and Findings The included HAIs were healthcare-associated pneumonia (HAP), healthcare-associated urinary tract infection (HA UTI), surgical site infection (SSI), healthcare-associated Clostridium difficile infection (HA CDI), healthcare-associated neonatal sepsis, and healthcare-associated primary bloodstream infection (HA primary BSI). The burden of these HAIs was measured in disability-adjusted life years (DALYs). Evidence relating to the disease progression pathway of each type of HAI was collected through systematic literature reviews, in order to estimate the risks attributable to HAIs. For each of the six HAIs, gender and age group prevalence from the ECDC PPS was converted into incidence rates by applying the Rhame and Sudderth formula. We adjusted for reduced life expectancy within the hospital population using three severity groups based on McCabe score data from the ECDC PPS. We estimated that 2,609,911 new cases of HAI occur every year in the European Union and European Economic Area (EU/EEA). The cumulative burden of the six HAIs was estimated at 501 DALYs per 100,000 general population each year in EU/EEA. HAP and HA primary BSI were associated with the highest burden and represented more than 60% of the total burden, with 169 and 145 DALYs per 100,000 total population, respectively. HA UTI, SSI, HA CDI, and HA primary BSI ranked as the third to sixth syndromes in terms of burden of disease

  20. The effects of feeder adjustment and trough space on growth performance of finishing pigs.

    PubMed

    Myers, A J; Goodband, R D; Tokach, M D; Dritz, S S; DeRouchey, J M; Nelssen, J L

    2012-12-01

    Two studies were conducted to determine the effects of feeder adjustment and trough space on growth performance of finishing pigs. In Exp. 1, 234 pigs (initial BW 41.5 kg) were used in an 89-d trial. Pigs were randomly allotted to 1 of 3 treatments with 9 replications of 8 pigs/pen and 1 replicate with 6 pigs/pen. Treatments consisted of a minimum feeder gap setting of 1.27, 1.91, or 2.54 cm. Feeders were adjusted to a minimum gap setting, but the agitation plate could be moved upward to a maximum opening of 1.91, 2.54, or 3.18 cm, respectively. Feeder adjustments of 1.27, 1.91, and 2.54 cm averaged 28, 58, and 75% pan coverage, respectively. From d 0 to 58, increasing feeder gap improved (linear; P ≤ 0.04) ADG and ADFI, but decreased (linear; P < 0.05) G:F. Although the response was linear for ADG, no increase occurred (quadratic; P = 0.15) beyond the 1.91-cm feeder gap setting. From d 58 to 89, increasing feeder gap setting tended (linear; P = 0.08) to worsen G:F. Overall (d 0 to 89), pigs fed with increasing feeder gap had decreased (linear; P <0.03) G:F due to increased (linear; P <0.02) ADFI. In Exp. 2, 288 pigs (initial BW 41.3 kg) were used in a 91-d study to evaluate the effects of feeder trough space (4.45 vs. 8.9 cm/pig) and minimum feeder gap opening of 1.27 cm (narrow) vs. 2.54 cm (wide). The treatments were arranged in a 2 × 2 factorial with 6 replications per treatment. Feeder trough space was altered by having pens of either 8 to 16 pigs per pen with all pigs provided 0.74 m(2) floor space per pig. From d 0 to 56 and 56 to 91, no adjustment × space interactions or effects of trough space were observed. From d 0 to 56, pigs with the wide feeder gap setting had decreased (P < 0.02) G:F compared with those that had the narrow feeder gap setting. From d 56 to 91, pigs with the wider feeder gap setting had increased (P < 0.001) ADFI, but consequently had decreased (P < 0.01) G:F. Overall (d 0 to 91), no trough space × feeder adjustment interactions

  1. Conformity expectations: Differential effects on IVF twins and singletons' parent-child relationships and adjustment.

    PubMed

    Anderson, Kayla N; Rueter, Martha A; Connor, Jennifer J; Chen, Muzi; Damario, Mark

    2015-08-01

    Increased utilization of in vitro fertilization (IVF) to treat infertility has resulted in a growing twin birthrate. Despite early childhood risks, twins have fewer psychosocial problems in middle childhood than singleton children. This study proposes that parents' conformity expectations for children have differential effects on parent-child relationships for twin and singleton children, which indirectly explains twins' more optimum psychosocial adjustment. Parental conformity expectations, parent-child relationship satisfaction, and children's emotional, behavioral, and attention problems were assessed in a sample of 288 6- to 12-year-old IVF-conceived twins and singletons. Overall, parents of twins had higher expectations for child conformity to parent rules than singleton parents. Path models demonstrate that twin status and parental expectations for child conformity interact to influence parent-child relationships, and this interaction indirectly accounted for differences in twins' and singletons' psychosocial adjustment. Findings suggest parenting constructs have differential influences on the association between twin status and parent-child relationships. Parenting research, predominantly conducted with singletons, should be reexamined before applying existing research to twin children and their families.

  2. Are effective teachers like good parents? Teaching styles and student adjustment in early adolescence.

    PubMed

    Wentzel, Kathryn R

    2002-01-01

    This study examined the utility of parent socialization models for understanding teachers' influence on student adjustment in middle school. Teachers were assessed with respect to their modeling of motivation and to Baumrind's parenting dimensions of control, maturity demands, democratic communication, and nurturance. Student adjustment was defined in terms of their social and academic goals and interest in class, classroom behavior, and academic performance. Based on information from 452 sixth graders from two suburban middle schools, results of multiple regressions indicated that the five teaching dimensions explained significant amounts of variance in student motivation, social behavior, and achievement. High expectations (maturity demands) was a consistent positive predictor of students' goals and interests, and negative feedback (lack of nurturance) was the most consistent negative predictor of academic performance and social behavior. The role of motivation in mediating relations between teaching dimensions and social behavior and academic achievement also was examined; evidence for mediation was not found. Relations of teaching dimensions to student outcomes were the same for African American and European American students, and for boys and girls. The implications of parent socialization models for understanding effective teaching are discussed.

  3. An examination of crossover and spillover effects of spousal and expatriate cross-cultural adjustment on expatriate outcomes.

    PubMed

    Takeuchi, Riki; Yun, Seokhwa; Tesluk, Paul E

    2002-08-01

    Integrating work-family and cross-cultural adjustment literatures, the researchers proposed and tested a spillover and crossover model of expatriates' cross-cultural adjustment with reciprocal relationships. Spillover effects refer to the influence that expatriate attitudes in a particular domain (e.g., work) have on attitudes in other domains (e.g., nonwork), whereas crossover effects refer to the influence of expatriate attitudes on the spouse's attitudes (and vice versa). Data collected from Japanese expatriates, their spouses, and their superiors strongly supported both spillover and crossover effects between expatriate and spousal cross-cultural adjustment. In addition, expatriates' cross-cultural adjustment was found to be related to satisfaction, which, in turn, was found to be negatively related to expatriates' intention to return to their homeland early.

  4. ESTIMATING THE INFLUENCE OF INDIVIDUAL POVERTY-ADJUSTED EDUCATIONAL ATTAINMENT ON TERM BIRTH WEIGHT USING CONDITIONAL MODELS

    EPA Science Inventory

    Reported maternal education is an important predictor of pregnancy outcomes. Like income, it is believed to allow women to locate in more favorable conditions than less educated or affluent peers. We examine the effect of reported educational attainment on term birth weight (birt...

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

    ERIC Educational Resources Information Center

    Tipton, Elizabeth; Pustejovsky, James E.

    2015-01-01

    Randomized experiments are commonly used to evaluate the effectiveness of educational interventions. The goal of the present investigation is to develop small-sample corrections for multiple contrast hypothesis tests (i.e., F-tests) such as the omnibus test of meta-regression fit or a test for equality of three or more levels of a categorical…

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

    PubMed Central

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

    2013-01-01

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

  7. Convective adjustment in baroclinic atmospheres

    NASA Technical Reports Server (NTRS)

    Emanuel, Kerry A.

    1986-01-01

    Local convection in planetary atmospheres is generally considered to result from the action of gravity on small regions of anomalous density. That in rotating baroclinic fluids the total potential energy for small scale convection contains a centrifugal as well as a gravitational contribution is shown. Convective adjustment in such an atmosphere results in the establishment of near adiabatic lapse rates of temperature along suitably defined surfaces of constant angular momentum, rather than in the vertical. This leads in general to sub-adiabatic vertical lapse rates. That such an adjustment actually occurs in the earth's atmosphere is shown by example and the magnitude of the effect for several other planetary atmospheres is estimated.

  8. Moderators and mediators of the effects of interparental conflict on children's adjustment.

    PubMed

    Kerig, P K

    1998-06-01

    Moderational and mediational models of the relationships among appraisals, interparental conflict, and children's adjustment were tested in a sample of 174 families with a school-age child. Parents rated children's exposure to interparental conflict and internalizing, externalizing, and total behavior problems. Children completed questionnaires regarding their appraisals of their parents' conflicts, including frequency and intensity, perceived threat, control, and self-blame, as well as measures of anxiety and depression. Results overall demonstrated more consistent support for the moderational than mediational hypotheses. Appraisals of conflict properties, threat, self-blame, and perceived control moderated the effects of interparental conflict on externalizing, total problems, and anxiety in boys. Conflict properties, threat, self-blame, perceived control, and self-calming acted as moderators of internalizing in girls.

  9. Moderators and mediators of the effects of interparental conflict on children's adjustment.

    PubMed

    Kerig, P K

    1998-06-01

    Moderational and mediational models of the relationships among appraisals, interparental conflict, and children's adjustment were tested in a sample of 174 families with a school-age child. Parents rated children's exposure to interparental conflict and internalizing, externalizing, and total behavior problems. Children completed questionnaires regarding their appraisals of their parents' conflicts, including frequency and intensity, perceived threat, control, and self-blame, as well as measures of anxiety and depression. Results overall demonstrated more consistent support for the moderational than mediational hypotheses. Appraisals of conflict properties, threat, self-blame, and perceived control moderated the effects of interparental conflict on externalizing, total problems, and anxiety in boys. Conflict properties, threat, self-blame, perceived control, and self-calming acted as moderators of internalizing in girls. PMID:9650626

  10. The effect of HWVP feed nitrate and carbonate content on glass redox adjustment

    SciTech Connect

    Wiemers, K.D.

    1996-03-01

    The Hanford Waste Vitrification Plant (HWVP) is being designed for the Department of Energy to immobilize pretreated radioactive high-level waste (HLW) as glass for geological disposal. In the HWVP formic acid will be added to the pretreated HLW prior to vitrification. The formic acid is added to adjust the feed rheology and to provide a reductant which maintains the feed in the melter within an acceptable redox range. This study was conducted to evaluate the effect of nitrate and carbonate concentrations in the pretreated neutralized current acid waste (NCAW) feed on the amount of formic acid required to obtain an acceptable glass redox state in the melter. The glass redox state was measured by the Fe{sup +2}/Fe{sup +3} ratio in the vitrified product.

  11. Can Genetic Estimators Provide Robust Estimates of the Effective Number of Breeders in Small Populations?

    PubMed Central

    Hoehn, Marion; Gruber, Bernd; Sarre, Stephen D.; Lange, Rebecca; Henle, Klaus

    2012-01-01

    The effective population size (Ne) is proportional to the loss of genetic diversity and the rate of inbreeding, and its accurate estimation is crucial for the monitoring of small populations. Here, we integrate temporal studies of the gecko Oedura reticulata, to compare genetic and demographic estimators of Ne. Because geckos have overlapping generations, our goal was to demographically estimate NbI, the inbreeding effective number of breeders and to calculate the NbI/Na ratio (Na = number of adults) for four populations. Demographically estimated NbI ranged from 1 to 65 individuals. The mean reduction in the effective number of breeders relative to census size (NbI/Na) was 0.1 to 1.1. We identified the variance in reproductive success as the most important variable contributing to reduction of this ratio. We used four methods to estimate the genetic based inbreeding effective number of breeders NbI(gen) and the variance effective populations size NeV(gen) estimates from the genotype data. Two of these methods - a temporal moment-based (MBT) and a likelihood-based approach (TM3) require at least two samples in time, while the other two were single-sample estimators - the linkage disequilibrium method with bias correction LDNe and the program ONeSAMP. The genetic based estimates were fairly similar across methods and also similar to the demographic estimates excluding those estimates, in which upper confidence interval boundaries were uninformative. For example, LDNe and ONeSAMP estimates ranged from 14–55 and 24–48 individuals, respectively. However, temporal methods suffered from a large variation in confidence intervals and concerns about the prior information. We conclude that the single-sample estimators are an acceptable short-cut to estimate NbI for species such as geckos and will be of great importance for the monitoring of species in fragmented landscapes. PMID:23139784

  12. Estimation of life-years gained and cost effectiveness based on cause-specific mortality.

    PubMed

    Kim, Lois G; Thompson, Simon G

    2011-07-01

    Cost-effectiveness analysis is usually based on life-years gained estimated from all-cause mortality. When an intervention affects only a few causes of death accounting for a small fraction of all deaths, this approach may lack precision. We develop a novel technique for cost-effectiveness analysis when life-years gained are estimated from cause-specific mortality, allowing for competing causes of death. In the context of randomised trial data, we adjust for other-cause mortality combined across randomised groups. This method yields a greater precision than analysis based on total mortality, and we show application to life-years gained, quality-adjusted life-years gained, incremental costs, and cost effectiveness. In multi-state health economic models, however, mortality from competing causes is commonly derived from national statistics and is assumed to be known and equal across intervention groups. In such models, our method based on cause-specific mortality and standard methods using total mortality give essentially identical estimates and precision. The methods are applied to a randomised trial and a health economic model, both of screening for abdominal aortic aneurysm. A gain in precision for cost-effectiveness estimates is clearly helpful for decision making, but it is important to ensure that 'cause-specific mortality' is defined to include all causes of death potentially affected by the intervention.

  13. Structural Nested Cumulative Failure Time Models to Estimate the Effects of Interventions

    PubMed Central

    Picciotto, Sally; Hernán, Miguel A.; Page, John H.; Young, Jessica G.; Robins, James M.

    2013-01-01

    In the presence of time-varying confounders affected by prior treatment, standard statistical methods for failure time analysis may be biased. Methods that correctly adjust for this type of covariate include the parametric g-formula, inverse probability weighted estimation of marginal structural Cox proportional hazards models, and g-estimation of structural nested accelerated failure time models. In this article, we propose a novel method to estimate the causal effect of a time-dependent treatment on failure in the presence of informative right-censoring and time-dependent confounders that may be affected by past treatment: g-estimation of structural nested cumulative failure time models (SNCFTMs). An SNCFTM considers the conditional effect of a final treatment at time m on the outcome at each later time k by modeling the ratio of two counterfactual cumulative risks at time k under treatment regimes that differ only at time m. Inverse probability weights are used to adjust for informative censoring. We also present a procedure that, under certain “no-interaction” conditions, uses the g-estimates of the model parameters to calculate unconditional cumulative risks under nondynamic (static) treatment regimes. The procedure is illustrated with an example using data from a longitudinal cohort study, in which the “treatments” are healthy behaviors and the outcome is coronary heart disease. PMID:24347749

  14. Application of (13)C ramp CPMAS NMR with phase-adjusted spinning sidebands (PASS) for the quantitative estimation of carbon functional groups in natural organic matter.

    PubMed

    Ikeya, Kosuke; Watanabe, Akira

    2016-01-01

    The composition of carbon (C) functional groups in natural organic matter (NOM), such as dissolved organic matter, soil organic matter, and humic substances, is frequently estimated using solid-state (13)C NMR techniques. A problem associated with quantitative analysis using general cross polarization/magic angle spinning (CPMAS) spectra is the appearance of spinning side bands (SSBs) split from the original center peaks of sp (2) hybridized C species (i.e., aromatic and carbonyl C). Ramp CP/phase-adjusted side band suppressing (PASS) is a pulse sequence that integrates SSBs separately and quantitatively recovers them into their inherent center peaks. In the present study, the applicability of ramp CP/PASS to NOM analysis was compared with direct polarization (DPMAS), another quantitative method but one that requires a long operation time, and/or a ramp CP/total suppression side band (ramp CP/TOSS) technique, a popular but non-quantitative method for deleting SSBs. The test materials were six soil humic acid samples with various known degrees of aromaticity and two fulvic acids. There were no significant differences in the relative abundance of alkyl C, O-alkyl C, and aromatic C between the ramp CP/PASS and DPMAS methods, while the signal intensities corresponding to aromatic C in the ramp CP/TOSS spectra were consistently less than the values obtained in the ramp CP/PASS spectra. These results indicate that ramp CP/PASS can be used to accurately estimate the C composition of NOM samples.

  15. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids.

    PubMed

    Neta, E R D; Johanningsmeier, S D; Drake, M A; McFeeters, R F

    2009-01-01

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on sour taste of equimolar protonated organic acid solutions and to investigate the potential roles of organic anions and sodium ions on sour taste perception. Despite equal concentrations of protonated acid species, sour taste intensity decreased significantly with increased pH for acetic, lactic, malic, and citric acids (P < 0.05). Total organic anion concentration did not explain the suppression of sour taste in solutions containing a blend of 3 organic acids with constant concentration of protonated organic acid species and hydrogen ions and variable organic anion concentrations (R(2)= 0.480, P = 0.12). Sour taste suppression in these solutions seemed to be more closely related to sodium ions added in the form of NaOH (R(2)= 0.861, P = 0.007). Addition of 20 mM NaCl to acid solutions resulted in significant suppression of sour taste (P = 0.016). However, sour taste did not decrease with further addition of NaCl up to 80 mM. Presence of sodium ions was clearly shown to decrease sour taste of organic acid solutions. Nonetheless, suppression of sour taste in pH adjusted single acid solutions was greater than what would be expected based on the sodium ion concentration alone, indicating an additional suppression mechanism may be involved.

  16. Effects of reduced plantar cutaneous afferent feedback on locomotor adjustments in dynamic stability during perturbed walking.

    PubMed

    Höhne, Angela; Stark, Christian; Brüggemann, Gert-Peter; Arampatzis, Adamantios

    2011-08-11

    This study examined the effects of reduced plantar cutaneous afferent feedback on predictive and feedback adaptive locomotor adjustments in dynamic stability during perturbed walking. Twenty-two matched participants divided between an experimental-group and a control-group performed a gait protocol, which included surface alterations to one covered exchangeable gangway-element (hard/soft). In the experimental-group, cutaneous sensation in both foot soles was reduced to the level of sensory peripheral neuropathy by means of intradermal injections of an anaesthetic solution, without affecting foot proprioception or muscles. The gait protocol consisted of baseline trials on a uniformly hard surface and an adaptation phase consisting of nineteen trials incorporating a soft gangway-element, interspersed with three trials using the hard surface-element (2nd, 8th and 19th). Dynamic stability was assessed by quantifying the margin of stability (MS), which was calculated as the difference between the base of support (BS) and the extrapolated centre of mass (CM). The horizontal velocity of the CM and its vertical projection in the anterior-posterior direction and the eigenfrequency of an inverted pendulum determine the extrapolated-CM. Both groups increased the BS at the recovery step in response to the first unexpected perturbation. These feedback corrections were used more extensively in the experimental-group, which led to a higher MS compared to the control-group, i.e. a more stable body-position. In the adaptation phase the MS returned to baseline similarly in both groups. In the trial on the hard surface directly after the first perturbation, both groups increased the MS at touchdown of the disturbed leg compared to baseline trials, indicating rapid predictive adjustments irrespective of plantar cutaneous input. Our findings demonstrate that the locomotor adaptational potential does not decrease due to the loss of plantar sensation.

  17. Estimating Principal Effectiveness. Working Paper 32

    ERIC Educational Resources Information Center

    Branch, Gregory; Hanushek, Eric; Rivkin, Steven

    2009-01-01

    Much has been written about the importance of school leadership, but there is surprisingly little systematic evidence on this topic. This paper presents preliminary estimates of key elements of the market for school principals, employing rich panel data on principals from Texas State. The consideration of teacher movements across schools suggests…

  18. Improvement of anticipatory postural adjustments for balance control: effect of a single training session

    PubMed Central

    Kanekar, Neeta; Aruin, Alexander S.

    2014-01-01

    Humans use anticipatory and compensatory postural strategies to maintain and restore balance when perturbed. Inefficient generation and utilization of anticipatory postural adjustments (APAs) is one of the reasons for postural instability. The aim of the study was to investigate the role of training in improvement of APAs and its effect on subsequent control of posture. Thirteen healthy young adults were exposed to predictable external perturbations before and after a single training session consisting of catches of a medicine ball thrown at the shoulder level. 3-D body kinematics, EMG activity of thirteen trunk and leg muscles, and ground reaction forces were recorded before and immediately after a single training session. Muscle onsets, EMG integrals, center of pressure (COP), and center of mass (COM) displacements were analyzed during the anticipatory and compensatory phases of postural control. The effect of a single training session was seen as significantly early muscle onsets and larger anticipatory COP displacements. As a result, significantly smaller peak COM displacements were observed after the perturbation indicating greater postural stability. The outcome of this study provides a background for examining the role of training in improvement of APAs and its effect on postural stability in individuals in need. PMID:25434280

  19. Improvement of anticipatory postural adjustments for balance control: effect of a single training session.

    PubMed

    Kanekar, Neeta; Aruin, Alexander S

    2015-04-01

    Humans use anticipatory and compensatory postural strategies to maintain and restore balance when perturbed. Inefficient generation and utilization of anticipatory postural adjustments (APAs) is one of the reasons for postural instability. The aim of the study was to investigate the role of training in improvement of APAs and its effect on subsequent control of posture. Thirteen healthy young adults were exposed to predictable external perturbations before and after a single training session consisting of catches of a medicine ball thrown at the shoulder level. 3-D body kinematics, EMG activity of thirteen trunk and lower limb muscles, and ground reaction forces were recorded before and immediately after a single training session. Muscle onsets, EMG integrals, center of pressure (COP), and center of mass (COM) displacements were analyzed during the anticipatory and compensatory phases of postural control. The effect of a single training session was seen as significantly early muscle onsets and larger anticipatory COP displacements. As a result, significantly smaller peak COM displacements were observed after the perturbation indicating greater postural stability. The outcome of this study provides a background for examining the role of training in improvement of APAs and its effect on postural stability in individuals in need.

  20. The Effects of Coping Humour and Gender on College Adjustment in Turkish Freshmen

    ERIC Educational Resources Information Center

    Oguz-Duran, Nagihan; Yuksel, Asuman

    2010-01-01

    The purpose of this study was to investigate the roles of coping humour and gender in the college adjustment of Turkish freshmen. Considering greater happiness and academic achievement as predictors of initial college adjustment, data were gathered from a sample of 574 students using the Subjective Well-Being Scale (SWS) and the Coping Humour…

  1. Adjusting Teacher Salaries for the Cost of Living: The Effect on Salary Comparisons and Policy Conclusions

    ERIC Educational Resources Information Center

    Stoddard, C.

    2005-01-01

    Teaching salaries are commonly adjusted for the cost of living, but this incorrectly accounts for welfare differences across states. Adjusting for area amenities and opportunities, however, produces more accurate salary comparisons. Amenities and opportunities can be measured by the wage premium other workers in a state face. The two methods…

  2. 42 CFR 495.211 - Payment adjustments effective for 2015 and subsequent MA payment years with respect to MA EPs and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 5 2013-10-01 2013-10-01 false Payment adjustments effective for 2015 and... effective for 2015 and subsequent MA payment years with respect to MA EPs and MA-affiliated eligible hospitals. (a) In general. Beginning for MA payment adjustment year 2015, payment adjustments set forth...

  3. 42 CFR 495.211 - Payment adjustments effective for 2015 and subsequent MA payment years with respect to MA EPs and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 5 2012-10-01 2012-10-01 false Payment adjustments effective for 2015 and... effective for 2015 and subsequent MA payment years with respect to MA EPs and MA-affiliated eligible hospitals. (a) In general. Beginning for MA payment adjustment year 2015, payment adjustments set forth...

  4. 42 CFR 495.211 - Payment adjustments effective for 2015 and subsequent MA payment years with respect to MA EPs and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Payment adjustments effective for 2015 and... effective for 2015 and subsequent MA payment years with respect to MA EPs and MA-affiliated eligible hospitals. (a) In general. Beginning for MA payment adjustment year 2015, payment adjustments set forth...

  5. Performance of Random Effects Model Estimators under Complex Sampling Designs

    ERIC Educational Resources Information Center

    Jia, Yue; Stokes, Lynne; Harris, Ian; Wang, Yan

    2011-01-01

    In this article, we consider estimation of parameters of random effects models from samples collected via complex multistage designs. Incorporation of sampling weights is one way to reduce estimation bias due to unequal probabilities of selection. Several weighting methods have been proposed in the literature for estimating the parameters of…

  6. Historical Channel Adjustment and Estimates of Selected Hydraulic Values in the Lower Sabine River and Lower Brazos River Basins, Texas and Louisiana

    USGS Publications Warehouse

    Heitmuller, Franklin T.; Greene, Lauren E.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Texas Water Development Board, evaluated historical channel adjustment and estimated selected hydraulic values at U.S. Geological Survey streamflow-gaging stations in the lower Sabine River Basin in Texas and Louisiana and lower Brazos River Basin in Texas to support geomorphic assessments of the Texas Instream Flow Program. Channel attributes including cross-section geometry, slope, and planform change were evaluated to learn how each river's morphology changed over the years in response to natural and anthropogenic disturbances. Historical and contemporary cross-sectional channel geometries at several gaging stations on each river were compared, planform changes were assessed, and hydraulic values were estimated including mean flow velocity, bed shear stress, Froude numbers, and hydraulic depth. The primary sources of historical channel morphology information were U.S. Geological Survey hard-copy discharge-measurement field notes. Additional analyses were done using computations of selected flow hydraulics, comparisons of historical and contemporary aerial photographs, comparisons of historical and contemporary ground photographs, evaluations of how frequently stage-discharge rating curves were updated, reviews of stage-discharge relations for field measurements, and considerations of bridge and reservoir construction activities. Based on historical cross sections at three gaging stations downstream from Toledo Bend Reservoir, the lower Sabine River is relatively stable, but is subject to substantial temporary scour-and-fill processes during floods. Exceptions to this characterization of relative stability include an episode of channel aggradation at the Sabine River near Bon Wier, Texas, during the 1930s, and about 2 to 3 feet of channel incision at the Sabine River near Burkeville, Texas, since the late 1950s. The Brazos River, at gaging stations downstream from Waco, Texas, has adjusted to a combination of

  7. Perceived parenting style and adolescent adjustment: revisiting directions of effects and the role of parental knowledge.

    PubMed

    Kerr, Margaret; Stattin, Håkan; Ozdemir, Metin

    2012-11-01

    In the present research on parenting and adolescent behavior, there is much focus on reciprocal, bidirectional, and transactional processes, but parenting-style research still adheres to a unidirectional perspective in which parents affect youth behavior but are unaffected by it. In addition, many of the most cited parenting-style studies have used measures of parental behavioral control that are questionable because they include measures of parental knowledge. The goals of this study were to determine whether including knowledge items might have affected results of past studies and to test the unidirectional assumption. Data were from 978 adolescents participating in a longitudinal study. Parenting-style and adolescent adjustment measures at 2 time points were used, with a 2-year interval between time points. A variety of internal and external adjustment measures were used. Results showed that including knowledge items in measures of parental behavioral control elevated links between behavioral control and adjustment. Thus, the results and conclusions of many of the most highly cited studies are likely to have been stronger than if the measures had focused strictly on parental behavior. In addition, adolescent adjustment predicted changes in authoritative and neglectful parenting styles more robustly than these styles predicted changes in adolescent adjustment. Adolescent adjustment also predicted changes in authoritativeness more robustly than authoritativeness predicted changes in adjustment. Thus, parenting style cannot be seen as independent of the adolescent. In summary, both the theoretical premises of parenting-style research and the prior findings should be revisited.

  8. Improved estimation of controlled direct effects in the presence of unmeasured confounding of intermediate variables.

    PubMed

    Kaufman, Sol; Kaufman, Jay S; MacLehose, Richard F; Greenland, Sander; Poole, Charles

    2005-06-15

    Adjusting for a causal intermediate is a common analytic strategy for estimating an average causal direct effect (ACDE). The ACDE is the component of the total exposure effect that is not relayed through the specified intermediate. Even if the total effect is unconfounded, the usual ACDE estimate may be biased when an unmeasured variable affects the intermediate and outcome variables. Using linear programming optimization to compute non-parametric bounds, we develop new ACDE estimators for binary measured variables in this causal structure, and use root mean square confounding bias (RMSB) to compare their performance with the usual stratified estimator in simulated distributions of target populations comprised of the 64 possible potential response types as well as distributions of target populations restricted to subsets of 18 or 12 potential response types defined by monotonicity or no-interactions assumptions of unit-level causal effects. We also consider target population distributions conditioned on fixed outcome risk among the unexposed, or fixed true ACDE in one stratum of the intermediate. Results show that a midpoint estimator constructed from the optimization bounds has consistently lower RMSB than the usual stratified estimator both unconditionally and conditioned on any risk in the unexposed. When conditioning on true ACDE, this midpoint estimator performs more poorly only when conditioned on an extreme true ACDE in one stratum of the intermediate, yet outperforms the stratified estimator in the other stratum when interaction is permitted. An alternate 'limit-modified crude' estimator can never perform less favourably than the stratified estimator, and often has lower RMSB. PMID:15742358

  9. Subthreshold-swing-adjustable tunneling-field-effect-transistor-based random-access memory for nonvolatile operation

    NASA Astrophysics Data System (ADS)

    Huh, In; Cheon, Woo Young; Choi, Woo Young

    2016-04-01

    A subthreshold-swing-adjustable tunneling-field-effect-transistor-based random-access memory (SAT RAM) has been proposed and fabricated for low-power nonvolatile memory applications. The proposed SAT RAM cell demonstrates adjustable subthreshold swing (SS) depending on stored information: small SS in the erase state ("1" state) and large SS in the program state ("0" state). Thus, SAT RAM cells can achieve low read voltage (Vread) with a large memory window in addition to the effective suppression of ambipolar behavior. These unique features of the SAT RAM are originated from the locally stored charge, which modulates the tunneling barrier width (Wtun) of the source-to-channel tunneling junction.

  10. Coping resources, perceived stress and adjustment to divorce among Israeli women: assessing effects.

    PubMed

    Kulik, Liat; Heine-Cohen, Etti

    2011-01-01

    The aim of this study was to examine how socioeconomic resources (level of education and evaluation of economic situation), cognitive resources (sense of coherence), emotional resources (the quality of relationship with the ex-spouse and the existence of a new romantic relationship), and perceived stress contribute to explaining the adjustment of Israeli women to divorce. Adjustment to divorce was examined along four dimensions: self-acceptance of divorce, disentanglement of the love relationship, symptoms of grief, and self-evaluation. The research sample consisted of 114 divorced Jewish women, all of whom had retained custody of their children. Among the resources examined, the contribution of sense of coherence to explaining adjustment to divorce was particularly significant, followed by the existence of a new romantic relationship. Furthermore, resources were found to interact with perceived stress in explaining women's adjustment to divorce.

  11. Efficient and Cost-Effective Use of Adjustable Canopy Hoods in a Chemistry Laboratory.

    ERIC Educational Resources Information Center

    Rothchild, Robert

    1988-01-01

    Suggests the use of small canopy hoods that provide flexibility of vertical and horizontal adjustment over the lab bench as a replacement for permanent hoods. Includes many safety related instances where canopy hoods should be used. (MVL)

  12. The effects of physiological adjustments on the perceptual and acoustical characteristics of simulated laryngeal vocal tremor.

    PubMed

    Lester, Rosemary A; Story, Brad H

    2015-08-01

    The purpose of this study was to determine if adjustments to the voice source [i.e., fundamental frequency (F0), degree of vocal fold adduction] or vocal tract filter (i.e., vocal tract shape for vowels) reduce the perception of simulated laryngeal vocal tremor and to determine if listener perception could be explained by characteristics of the acoustical modulations. This research was carried out using a computational model of speech production that allowed for precise control and manipulation of the glottal and vocal tract configurations. Forty-two healthy adults participated in a perceptual study involving pair-comparisons of the magnitude of "shakiness" with simulated samples of laryngeal vocal tremor. Results revealed that listeners perceived a higher magnitude of voice modulation when simulated samples had a higher mean F0, greater degree of vocal fold adduction, and vocal tract shape for /i/ vs /ɑ/. However, the effect of F0 was significant only when glottal noise was not present in the acoustic signal. Acoustical analyses were performed with the simulated samples to determine the features that affected listeners' judgments. Based on regression analyses, listeners' judgments were predicted to some extent by modulation information present in both low and high frequency bands. PMID:26328711

  13. The effects of physiological adjustments on the perceptual and acoustical characteristics of simulated laryngeal vocal tremor

    PubMed Central

    Lester, Rosemary A.; Story, Brad H.

    2015-01-01

    The purpose of this study was to determine if adjustments to the voice source [i.e., fundamental frequency (F0), degree of vocal fold adduction] or vocal tract filter (i.e., vocal tract shape for vowels) reduce the perception of simulated laryngeal vocal tremor and to determine if listener perception could be explained by characteristics of the acoustical modulations. This research was carried out using a computational model of speech production that allowed for precise control and manipulation of the glottal and vocal tract configurations. Forty-two healthy adults participated in a perceptual study involving pair-comparisons of the magnitude of “shakiness” with simulated samples of laryngeal vocal tremor. Results revealed that listeners perceived a higher magnitude of voice modulation when simulated samples had a higher mean F0, greater degree of vocal fold adduction, and vocal tract shape for /i/ vs /ɑ/. However, the effect of F0 was significant only when glottal noise was not present in the acoustic signal. Acoustical analyses were performed with the simulated samples to determine the features that affected listeners' judgments. Based on regression analyses, listeners' judgments were predicted to some extent by modulation information present in both low and high frequency bands. PMID:26328711

  14. Age effects on the control of dynamic balance during step adjustments under temporal constraints.

    PubMed

    Nakano, Wataru; Fukaya, Takashi; Kobayashi, Satomi; Ohashi, Yukari

    2016-06-01

    This study investigated the age effects on the control of dynamic balance during step adjustments under temporal constraints. Fifteen young adults and 14 older adults avoided a virtual white planar obstacle by lengthening or shortening their steps under free or constrained conditions. In the anterior-posterior direction, older adults demonstrated significantly decreased center of mass velocity at the swing foot contact under temporal constraints. Additionally, the distances between the 'extrapolated center of mass' position and base of support at the swing foot contact were greater in older adults than young adults. In the mediolateral direction, center of mass displacement was significantly increased in older adults compared with young adults. Consequently, older adults showed a significantly increased step width at the swing foot contact in the constraint condition. Overall, these data suggest that older adults demonstrate a conservative strategy to maintain anterior-posterior stability. By contrast, although older adults are able to modulate their step width to maintain mediolateral dynamic balance, age-related changes in mediolateral balance control under temporal constraints may increase the risk of falls in the lateral direction during obstacle negotiation.

  15. Estimating and Testing Mediation Effects with Censored Data

    ERIC Educational Resources Information Center

    Wang, Lijuan; Zhang, Zhiyong

    2011-01-01

    This study investigated influences of censored data on mediation analysis. Mediation effect estimates can be biased and inefficient with censoring on any one of the input, mediation, and output variables. A Bayesian Tobit approach was introduced to estimate and test mediation effects with censored data. Simulation results showed that the Bayesian…

  16. Accounting for uncertainty in confounder and effect modifier selection when estimating average causal effects in generalized linear models.

    PubMed

    Wang, Chi; Dominici, Francesca; Parmigiani, Giovanni; Zigler, Corwin Matthew

    2015-09-01

    Confounder selection and adjustment are essential elements of assessing the causal effect of an exposure or treatment in observational studies. Building upon work by Wang et al. (2012, Biometrics 68, 661-671) and Lefebvre et al. (2014, Statistics in Medicine 33, 2797-2813), we propose and evaluate a Bayesian method to estimate average causal effects in studies with a large number of potential confounders, relatively few observations, likely interactions between confounders and the exposure of interest, and uncertainty on which confounders and interaction terms should be included. Our method is applicable across all exposures and outcomes that can be handled through generalized linear models. In this general setting, estimation of the average causal effect is different from estimation of the exposure coefficient in the outcome model due to noncollapsibility. We implement a Bayesian bootstrap procedure to integrate over the distribution of potential confounders and to estimate the causal effect. Our method permits estimation of both the overall population causal effect and effects in specified subpopulations, providing clear characterization of heterogeneous exposure effects that may vary considerably across different covariate profiles. Simulation studies demonstrate that the proposed method performs well in small sample size situations with 100-150 observations and 50 covariates. The method is applied to data on 15,060 US Medicare beneficiaries diagnosed with a malignant brain tumor between 2000 and 2009 to evaluate whether surgery reduces hospital readmissions within 30 days of diagnosis.

  17. Accounting for Uncertainty in Confounder and Effect Modifier Selection when Estimating Average Causal Effects in Generalized Linear Models

    PubMed Central

    Wang, Chi; Dominici, Francesca; Parmigiani, Giovanni; Zigler, Corwin Matthew

    2015-01-01

    Summary Confounder selection and adjustment are essential elements of assessing the causal effect of an exposure or treatment in observational studies. Building upon work by Wang et al. (2012) and Lefebvre et al. (2014), we propose and evaluate a Bayesian method to estimate average causal effects in studies with a large number of potential confounders, relatively few observations, likely interactions between confounders and the exposure of interest, and uncertainty on which confounders and interaction terms should be included. Our method is applicable across all exposures and outcomes that can be handled through generalized linear models. In this general setting, estimation of the average causal effect is different from estimation of the exposure coefficient in the outcome model due to non-collapsibility. We implement a Bayesian bootstrap procedure to integrate over the distribution of potential confounders and to estimate the causal effect. Our method permits estimation of both the overall population causal effect and effects in specified subpopulations, providing clear characterization of heterogeneous exposure effects that may vary considerably across different covariate profiles. Simulation studies demonstrate that the proposed method performs well in small sample size situations with 100 to 150 observations and 50 covariates. The method is applied to data on 15060 US Medicare beneficiaries diagnosed with a malignant brain tumor between 2000 and 2009 to evaluate whether surgery reduces hospital readmissions within thirty days of diagnosis. PMID:25899155

  18. [Estimation of the hypoglycemic effect of phytoecdysteroids].

    PubMed

    Syrov, V N; Iuldasheva, N Kh; Égamova, F R; Ismailova, G I; Abdullaev, N D; Khushbaktova, Z A

    2012-01-01

    A series of phytoecodysteroids, including alpha-ecdysone, 2-deoxy-alpha-ecdysone, and 2-deoxyecdysterone isolated from Silene praemixta, integristerone A and ecdysterone isolated from Rhaponticum carthamoides and 22-acetylcyasterone and turkesterone isolated from Ajuga turkestanica, exhibit a pronounced hypoglycemic effect in experiments on intact male rats. The most active compounds--ecdysteron and turkesterone--also produce an expressed hypoglycemic effect in animals with model hyperglycemia induced by the administration of glucose, adrenalin and alloxan. Phytoecdysteroids are substances possessing protein-anabolic activity and are somewhat similar to steranobols in this aspect. Phytoecdysteroids exhibit unidirectional effect and are well comparable with steranabol actionon the carbohydrate metabolism. PMID:22834126

  19. Degrees of freedom in interspecific allometry: an adjustment for the effects of phylogenetic constraint.

    PubMed

    Smith, R J

    1994-01-01

    The data used in studies of bivariate interspecific allometry usually violate the assumption of statistical independence. Although the traits of each species are commonly treated as independent, the expression of a trait among species within a genus may covary because of shared common ancestry. The same effect exists for genera within a family and so on up the phylogenetic hierarchy. Determining sample size by counting data points overestimates the effective sample size, which then leads to overestimating the degrees of freedom that should be used in calculating probabilities and confidence intervals. This results in an inflated Type 1 error rate. Although some workers (e.g., Felsenstein [1985] Am. Nat. 125:1-15) have suggested that this issue may invalidate interspecific allometry as a comparative method, a correction for the problem can be approximated with variance components from a nested analysis of variance. Variance components partition the total variation in the data set among the levels of the nested hierarchy. If the variance component for each nested level is weighted by the number of groups at that level, the sum of these values is an estimate of an effective sample size for the data set which reflects the effects of phylogenetic constraint. Analysis of two data sets, using taxonomy to define levels of the nested hierarchy, suggests that it has been common for published studies of interspecific allometry to severely overestimate the number of degrees of freedom. Interspecific allometry remains an important comparative method for evaluating questions concerning individual species that are not similarly addressed by the format of most of the newer comparative methods. With the correction proposed here for estimating degrees of freedom, the major statistical weakness of the procedure is substantially reduced. PMID:8141245

  20. Estimated equilibrated dietary intakes for nine minerals (Na, K, Ca, Mg, P, Fe, Zn, Cu, and Mn) adjusted by mineral balance medians in young Japanese females.

    PubMed

    Nishimuta, Mamoru; Kodama, Naoko; Shimada, Mieko; Yoshitake, Yutaka; Matsuzaki, Nobue; Morikuni, Eiko

    2012-01-01

    The present study sought to determine estimated equilibrated dietary intakes (EEDIs) for nine essential minerals: sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe), zinc (Zn), copper (Cu), and manganese (Mn), using data from 17 human mineral balance studies conducted from 1986 to 2007 (subjects=178). Among these studies, two used male subjects, two subjected some or all subjects to sodium restriction, and one study utilized a low protein diet; these subjects were not included in the present analysis. Consequently, data from 13 studies of young female subjects (n=131) consuming a standard diet were selected. Balance distribution medians for six of the minerals (Na, K, Mg, Fe, Zn and Cu) were positive, so the data were adjusted to set the medians of the balances to zero. Medians for the other minerals (Ca, P and Mn) were close to zero and were not adjusted. Intake and balance for each mineral were divided by body weight (BW), lean body mass (LBM), and standard body weight (SBW), which was calculated using height and standard body mass index (BMI=22), and EEDIs were calculated as the intercept of a simple regression equation. When relationships between intake and balance of a mineral were not significant in the regression equation, a significant regression equation comparing intake and balance of another mineral was used to calculate the intercept. Significant simple regression equations were not obtained from any of the three parameters of Na or Zn, or for two of the parameters of P; thus, K, Fe and Ca balances were used to determine the intercepts for Na, Zn and P, respectively. EEDIs for the minerals were: Na (67.9, 89.0, 62.5), K (39.5, 53.5, 37.4), Ca (11.0, 14.4, 10.1), Mg (4.18, 5.51, 3.86), P (18.7, 24.6, 17.3) (mg/kg BW/d, mg/kg LBM/d, mg/kg SBW/d), Fe (180, 237, 165), Zn (181, 241, 166), [corrected] Cu (32.3, 42.6, 29.7), [corrected] Mn (55.1, 72.1, 50.7) (µg/kg BW/d, µg/kg LBM/d, µg/kg SBW/d), respectively. These values

  1. The Effects of Occupational Work Adjustment on Factors Leading to High School Drop Out in Rural Northwest Ohio.

    ERIC Educational Resources Information Center

    Dietrich, Angela

    The effect of four Occupational Work Adjustment (OWA) programs on risk factors leading to students dropping out of high school was assessed. Data were gathered from four OWA teachers in high schools in Northwest Ohio; information was provided for 27 individual students and 2 groups of 28 students each for the 1992-93 school year. The following…

  2. Previous International Experience, Cross-Cultural Training, and Expatriates' Cross-Cultural Adjustment: Effects of Cultural Intelligence and Goal Orientation

    ERIC Educational Resources Information Center

    Koo Moon, Hyoung; Kwon Choi, Byoung; Shik Jung, Jae

    2012-01-01

    Although various antecedents of expatriates' cross-cultural adjustment have been addressed, previous international experience, predeparture cross-cultural training, and cultural intelligence (CQ) have been most frequently examined. However, there are few attempts that explore the effects of these antecedents simultaneously or consider the possible…

  3. Does HPA-Axis Dysregulation Account for the Effects of Income on Effortful Control and Adjustment in Preschool Children?

    ERIC Educational Resources Information Center

    Lengua, Liliana J.; Zalewski, Maureen; Fisher, Phil; Moran, Lyndsey

    2013-01-01

    The effects of low income on children's adjustment might be accounted for by disruptions to hypothalamic-pituitary-adrenal (HPA)-axis activity and to the development of effortful control. Using longitudinal data and a community sample of preschool-age children (N?=?306, 36-39?months) and their mothers, recruited to over-represent low-income…

  4. Effects of a Developmentally Based Intervention with Teachers on Native American and White Early Adolescents' Schooling Adjustment in Rural Settings

    ERIC Educational Resources Information Center

    Hamm, Jill V.; Farmer, Thomas W.; Robertson, Dylan; Dadisman, Kimberly A.; Murray, Allen; Meece, Judith L.; Song, Samuel Y.

    2010-01-01

    This study reports the effectiveness of a developmentally based, teacher professional development intervention aimed at improving early adolescent school adjustment. Teachers in rural schools in a Northern Plains state took part in professional development activities across a year. Following a randomized control trial design, Native American and…

  5. The Effects of the Marriage Enrichment Program Based on the Cognitive-Behavioral Approach on the Marital Adjustment of Couples

    ERIC Educational Resources Information Center

    Kalkan, Melek; Ersanli, Ercumend

    2008-01-01

    The aim of this study is to investigate the effects of the marriage enrichment program based on the cognitive-behavioral approach on levels of marital adjustment of individuals. The experimental and control group of this research was totally composed of 30 individuals. A pre-test post-test research model with control group was used in this…

  6. Exploring the Effects of Social Networking on Students' Perceptions of Social Connectedness, Adjustment, Academic Engagement, and Institutional Commitment

    ERIC Educational Resources Information Center

    Hansen, Michele J.; Childress, Janice E.; Trujillo, Daniel J.

    2010-01-01

    Social networking is a tool being explored by many institutions as a means of connecting to and communicating with students. This study explores whether or not students' use of social networking services (SNSs) has significant effects on social connectedness, college adjustment, academic engagement, and institutional commitment. Students' use of…

  7. The Moderating Effect of Machiavellianism on the Relationships between Bullying, Peer Acceptance, and School Adjustment in Adolescents

    ERIC Educational Resources Information Center

    Wei, Hsi-Sheng; Chen, Ji-Kang

    2012-01-01

    This study examined the moderating effect of Machiavellianism on the relationships between bullying, peer acceptance, and school adjustment (rule-following behavior and academic performance) among 216 middle school 7th-graders in Taipei, Taiwan. The participants were divided into two groups according to their Machiavellianism. Multi-group path…

  8. The Effectiveness of the Strength-Centered Career Adjustment Model for Dual-Career Women in Taiwan

    ERIC Educational Resources Information Center

    Wang, Yu-Chen; Tien, Hsiu-Lan Shelley

    2011-01-01

    The authors investigated the effectiveness of a Strength-Centered Career Adjustment Model for dual-career women (N = 28). Fourteen women in the experimental group received strength-centered career counseling for 6 to 8 sessions; the 14 women in the control group received test services in 1 to 2 sessions. All participants completed the Personal…

  9. Shyness and School Adjustment among Chinese Preschool Children: Examining the Moderating Effect of Gender and Teacher-Child Relationship

    ERIC Educational Resources Information Center

    Wu, YunPeng; Wu, JianFen; Chen, YingMin; Han, Lei; Han, PiGuo; Wang, Peng; Gao, Fengqiang

    2015-01-01

    Research Findings: The current study examined the moderating effects of gender and teacher-child relationship on the association between shyness and school adjustment (school liking and avoidance, cooperative and independent participation). The sample consisted of 524 preschool students from 3 cities of Shandong province in northern China. Mothers…

  10. The Effectiveness of Emotionally Focused Couples Therapy on Sexual Satisfaction and Marital Adjustment of Infertile Couples with Marital Conflicts

    PubMed Central

    Soleimani, Ali Akbar; Najafi, Maryam; Ahmadi, Khodabakhsh; Javidi, Nasirudin; Hoseini Kamkar, Elnaz; Mahboubi, Mohamad

    2015-01-01

    Background The purpose of this investigation is to determine the efficacy of emotionally focused couples therapy (EFT-C) on enhancement of marital adjustment in infertile couples. Materials and Methods This was a semi-experimental study with a pre- and post-test design. We selected 30 infertile couples (60 subjects) by purposive sampling. Couples were randomly assigned to two groups, sample and control. Each group consisted of 15 couples who had marital maladjustment and low sexual satisfaction. Couples answered the marital adjustment and sexual satisfaction questionnaires at baseline after which the sample group received 10 sessions of EFT-C. Results Results of pre-test and post-test showed that EFT-C significantly impacted marital adjustment and sexual satisfaction. Conclusion EFT-C had a significant effect on enhancement of satisfaction, cohesion and affectional expression. This approach impacted physical and emotional sexual satisfaction of infertile couples. PMID:26644864

  11. An effect of physical activity-based recreation programs on children's optimism, humor styles, and school life adjustment.

    PubMed

    Koo, Jae-Eun; Lee, Gwang-Uk

    2015-06-01

    This study puts its purpose in identifying the effect of the participation in physical activity-based recreation programs on the optimism of children, humor styles, and school life adjustment. To achieve the study purpose, this study selected 190 subjects as samples were extracted targeting senior students of elementary schools who participated in the physical activity-based recreation in the metropolitan areas as of 2014. As research methods, questionnaire papers were used and reliability analysis, factor analysis, correlation analysis, and multiple regression analysis were conducted by utilizing SPSS 18.0 after inputting analysis data into the computer. The study results, obtained in this study are as follows: First, in terms of the effect of the participation in physical activity-based recreation programs on optimism, participation frequency and participation intensity would have an effect on optimism, while participation period would have a significant effect on being positive among the sub-factors of optimism. Second, participation in physical activity-based recreation programs might have a significant effect on humor styles. Third, in terms of the effect of the participation in physical activity-based recreation programs on the school life adjustment, it was demonstrated that participation period and participation intensity would have a significant effect on school life adjustment, while participation frequency would have a significant effect on regulation-observance and school life satisfaction.

  12. Compliance-Effect Correlation Bias in Instrumental Variables Estimators

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2010-01-01

    Instrumental variable estimators hold the promise of enabling researchers to estimate the effects of educational treatments that are not (or cannot be) randomly assigned but that may be affected by randomly assigned interventions. Examples of the use of instrumental variables in such cases are increasingly common in educational and social science…

  13. The Effect of Training on Accuracy of Angle Estimation.

    ERIC Educational Resources Information Center

    Waller, T. Gary; Wright, Robert H.

    This report describes a study to determine the effect of training on accuracy in estimating angles. The study was part of a research program directed toward improving navigation techniques for low-level flight in Army aircraft and was made to assess the feasibility of visually estimating angles on a map in order to determine angles of drift.…

  14. Estimating the willingness to pay for a quality-adjusted life year in Thailand: does the context of health gain matter?

    PubMed Central

    Thavorncharoensap, Montarat; Teerawattananon, Yot; Natanant, Sirin; Kulpeng, Wantanee; Yothasamut, Jomkwan; Werayingyong, Pitsaphun

    2013-01-01

    Background This study aims to elicit the value of the willingness to pay (WTP) for a quality-adjusted life year (QALY) and to examine the factors associated with the WTP for a QALY (WTP/QALY) value under the Thai health care setting. Methods A community-based survey was conducted among 1191 randomly selected respondents. Each respondent was interviewed face-to-face to elicit his/her health state preference in each of three pairs of health conditions: (1) unilateral and bilateral blindness, (2) paraplegia and quadriplegia, and (3) mild and moderate allergies. A visual analog scale (VAS) and time trade off (TTO) were used as the eliciting methods. Subsequently, the respondents were asked about their WTP for the treatment and prevention of each pair of health conditions by using a bidding-game technique. Results With regards to treatment, the mean WTP for a QALY value (WTP/QALYtreatment) estimated by the TTO method ranged from 59,000 to 285,000 baht (16.49 baht = US$1 purchasing power parity [PPP]). In contrast, the mean WTP for a QALY value in terms of prevention (WTP/QALYprevention) was significantly lower, ranging from 26,000 to 137,000 baht. Gender, household income, and hypothetical scenarios were also significant factors associated with the WTP/QALY values. Conclusion The WTP/QALY values elicited in this study were approximately 0.4 to 2 times Thailand’s 2008 GDP per capita. These values were in line with previous studies conducted in several different settings. This study’s findings clearly support the opinion that a single ceiling threshold should not be used for the resource allocation of all types of interventions. PMID:23345984

  15. Implicit advance knowledge effects on the interplay between arm movements and postural adjustments in catching.

    PubMed

    Tijtgat, Pieter; Vanrenterghem, Jos; Bennett, Simon J; De Clercq, Dirk; Savelsbergh, Geert J P; Lenoir, Matthieu

    2012-06-19

    This study examined if, and how, implicit advance knowledge of upcoming ball speed influences the interplay between arm movements and concomitant postural adjustments in one-handed catching. While standing, subjects were asked to catch balls that were presented with or without implicit advance knowledge of four different ball speeds. Full body kinematics and ground reaction forces were measured, which allowed the assessment of arm movements and postural adjustments through the momentum of the arm, rest of the body and whole body. Providing implicit advance knowledge induced a forward arm raising movement scaled to ball speed in the initial transport phase. However, the accompanying backward postural adjustments were unaffected, which is suggestive of a passive control mechanism. In the subsequent grasping phase, the scaling of arm raising movement exhibited in the presence of implicit advance knowledge resulted in a reduced need for postural adjustments, particularly at the highest ball speed. Together, these findings suggest that cortical involvement based on previous experience not only shapes the arm movements but also the subsequent interplaying postural responses.

  16. The Effects of Divorce and Parental Conflict on Children's Adjustment: A Prospective Study.

    ERIC Educational Resources Information Center

    Shaw, Daniel

    Replicating the methodology used by Block, Block, and Gjerde (1986), a prospective, longitudinal examination was made of relations between divorce and children's adjustment. Data from the New York Longitudinal Study (NYLS), originally collected by Thomas, Chess, and Birch (1963, 1968, 1977, 1983, 1984) was analyzed. The NYLS assessed children's…

  17. Location Memory in the Real World: Category Adjustment Effects in 3-Dimensional Space

    ERIC Educational Resources Information Center

    Holden, Mark P.; Newcombe, Nora S.; Shipley, Thomas F.

    2013-01-01

    The ability to remember spatial locations is critical to human functioning, both in an evolutionary and in an everyday sense. Yet spatial memories and judgments often show systematic errors and biases. Bias has been explained by models such as the Category Adjustment model (CAM), in which fine-grained and categorical information about locations…

  18. Effects of Individual Characteristics on Expatriates' Adjustment and Job Performance

    ERIC Educational Resources Information Center

    Bhatti, Muhammad Awais; Kaur, Sharan; Battour, Mohamed Mohamed

    2013-01-01

    Purpose: Researchers have been focusing on the predictors of expatriates' adjustment and job performance at different levels (individual level, organizational level and societal level), but still some of the predictors have been ignored or unclear in the expatriate literature. The purpose of this paper is to develop a comprehensive framework…

  19. A Novel Moisture Adjusted Vegetation Index (MAVI) to Reduce Background Reflectance and Topographical Effects on LAI Retrieval

    PubMed Central

    Zhu, Gaolong; Ju, Weimin; Chen, J. M.; Liu, Yibo

    2014-01-01

    A new moisture adjusted vegetation index (MAVI) is proposed using the red, near infrared, and shortwave infrared (SWIR) reflectance in band-ratio form in this paper. The effectiveness of MAVI in retrieving leaf area index (LAI) is investigated using Landsat-5 data and field LAI measurements in two forest and two grassland areas. The ability of MAVI to retrieve forest LAI under different background conditions is further evaluated using canopy reflectance of Jack Pine and Black Spruce forests simulated by the 4-Scale model. Compared with several commonly used two-band vegetation index, such as normalized difference vegetation index, soil adjusted vegetation index, modified soil adjusted vegetation index, optimized soil adjusted vegetation index, MAVI is a better predictor of LAI, on average, which can explain 70% of variations of LAI in the four study areas. Similar to other SWIR-related three-band vegetation index, such as modified normalized difference vegetation index (MNDVI) and reduced simple ratio (RSR), MAVI is able to reduce the background reflectance effects on forest canopy LAI retrieval. MAVI is more suitable for retrieving LAI than RSR and MNDVI, because it avoids the difficulty in properly determining the maximum and minimum SWIR values required in RSR and MNDVI, which improves the robustness of MAVI in retrieving LAI of different land cover types. Moreover, MAVI is expressed as ratios between different spectral bands, greatly reducing the noise caused by topographical variations, which makes it more suitable for applications in mountainous area. PMID:25025128

  20. A novel moisture adjusted vegetation index (MAVI) to reduce background reflectance and topographical effects on LAI retrieval.

    PubMed

    Zhu, Gaolong; Ju, Weimin; Chen, J M; Liu, Yibo

    2014-01-01

    A new moisture adjusted vegetation index (MAVI) is proposed using the red, near infrared, and shortwave infrared (SWIR) reflectance in band-ratio form in this paper. The effectiveness of MAVI in retrieving leaf area index (LAI) is investigated using Landsat-5 data and field LAI measurements in two forest and two grassland areas. The ability of MAVI to retrieve forest LAI under different background conditions is further evaluated using canopy reflectance of Jack Pine and Black Spruce forests simulated by the 4-Scale model. Compared with several commonly used two-band vegetation index, such as normalized difference vegetation index, soil adjusted vegetation index, modified soil adjusted vegetation index, optimized soil adjusted vegetation index, MAVI is a better predictor of LAI, on average, which can explain 70% of variations of LAI in the four study areas. Similar to other SWIR-related three-band vegetation index, such as modified normalized difference vegetation index (MNDVI) and reduced simple ratio (RSR), MAVI is able to reduce the background reflectance effects on forest canopy LAI retrieval. MAVI is more suitable for retrieving LAI than RSR and MNDVI, because it avoids the difficulty in properly determining the maximum and minimum SWIR values required in RSR and MNDVI, which improves the robustness of MAVI in retrieving LAI of different land cover types. Moreover, MAVI is expressed as ratios between different spectral bands, greatly reducing the noise caused by topographical variations, which makes it more suitable for applications in mountainous area. PMID:25025128

  1. A novel moisture adjusted vegetation index (MAVI) to reduce background reflectance and topographical effects on LAI retrieval.

    PubMed

    Zhu, Gaolong; Ju, Weimin; Chen, J M; Liu, Yibo

    2014-01-01

    A new moisture adjusted vegetation index (MAVI) is proposed using the red, near infrared, and shortwave infrared (SWIR) reflectance in band-ratio form in this paper. The effectiveness of MAVI in retrieving leaf area index (LAI) is investigated using Landsat-5 data and field LAI measurements in two forest and two grassland areas. The ability of MAVI to retrieve forest LAI under different background conditions is further evaluated using canopy reflectance of Jack Pine and Black Spruce forests simulated by the 4-Scale model. Compared with several commonly used two-band vegetation index, such as normalized difference vegetation index, soil adjusted vegetation index, modified soil adjusted vegetation index, optimized soil adjusted vegetation index, MAVI is a better predictor of LAI, on average, which can explain 70% of variations of LAI in the four study areas. Similar to other SWIR-related three-band vegetation index, such as modified normalized difference vegetation index (MNDVI) and reduced simple ratio (RSR), MAVI is able to reduce the background reflectance effects on forest canopy LAI retrieval. MAVI is more suitable for retrieving LAI than RSR and MNDVI, because it avoids the difficulty in properly determining the maximum and minimum SWIR values required in RSR and MNDVI, which improves the robustness of MAVI in retrieving LAI of different land cover types. Moreover, MAVI is expressed as ratios between different spectral bands, greatly reducing the noise caused by topographical variations, which makes it more suitable for applications in mountainous area.

  2. Estimating Contrail Climate Effects from Satellite Data

    NASA Technical Reports Server (NTRS)

    Minnis, Patrick; Duda, David P.; Palikonda, Rabindra; Bedka, Sarah T.; Boeke, Robyn; Khlopenkov, Konstantin; Chee, Thad; Bedka, Kristopher T.

    2011-01-01

    An automated contrail detection algorithm (CDA) is developed to exploit six of the infrared channels on the 1-km MODerate-resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites. The CDA is refined and balanced using visual error analysis. It is applied to MODIS data taken by Terra and Aqua over the United States during 2006 and 2008. The results are consistent with flight track data, but differ markedly from earlier analyses. Contrail coverage is a factor of 4 less than other retrievals and the retrieved contrail optical depths and radiative forcing are smaller by approx.30%. The discrepancies appear to be due to the inability to detect wider, older contrails that comprise a significant amount of the contrail coverage. An example of applying the algorithm to MODIS data over the entire Northern Hemisphere is also presented. Overestimates of contrail coverage are apparent in some tropical regions. Methods for improving the algorithm are discussed and are to be implemented before analyzing large amounts of Northern Hemisphere data. The results should be valuable for guiding and validating climate models seeking to account for aviation effects on climate.

  3. Limitations of ozone data assimilation with adjustment of NOx emissions: mixed effects on NO2 forecast over Beijing and surrounding areas

    NASA Astrophysics Data System (ADS)

    Tang, X.; Zhu, J.; Wang, Z. F.; Gbaguidi, A.; Lin, C. Y.; Xin, J. Y.; Song, T.; Hu, B.

    2015-12-01

    This study investigates a cross-variable ozone data assimilation (DA) method based on an ensemble Kalman filter (EnKF) that has been validated as an efficient approach for improving ozone forecasts. The main purpose is to delve into the impacts of the cross-variable adjustment of nitrogen oxides (NOx) emissions on the nitrogen dioxide (NO2) forecasts over Beijing and surrounding regions during the 2008 Beijing Olympic Games. A mixed effect on the NO2 forecasts was observed during the application of the cross-variable assimilation approach in real-data assimilation (RDA) experiments. The method improved the NO2 forecast over almost half of the urban sites with reductions of the root mean square errors (RMSEs) by 15-36 % in contrast to big increases of the RMSEs over other urban stations by 56-239 %. Over the urban stations with negative DA impacts, improvement of the NO2 forecasts with 7 % reduction of the RMSEs was noticed during the night and the morning vs. significant deterioration of the forecasts during daytime with 190 % increase of the RMSEs, suggesting the negative DA impacts mainly occurred during daytime. Ideal data assimilation (IDA) experiments with a box model and the same cross-variable assimilation method, as a further investigation, confirmed the mixed effects found in the RDA experiments. An improvement of the NOx emission estimation was obtained from the cross-variable assimilation under relatively small errors in the prior estimation of NOx emissions during daytime, while deterioration of the NOx emission estimation was found under large biases in the prior estimation of NOx emissions during daytime. However, the cross-variable assimilation improved the NOx emission estimations during the night and the morning even with large biases in the prior estimations. The mixed effects observed in the cross-variable assimilation, i.e., positive DA impacts on NO2 forecast over some urban sites, negative DA impacts over the other urban sites and weak DA

  4. Unbiased estimation in seamless phase II/III trials with unequal treatment effect variances and hypothesis-driven selection rules.

    PubMed

    Robertson, David S; Prevost, A Toby; Bowden, Jack

    2016-09-30

    Seamless phase II/III clinical trials offer an efficient way to select an experimental treatment and perform confirmatory analysis within a single trial. However, combining the data from both stages in the final analysis can induce bias into the estimates of treatment effects. Methods for bias adjustment developed thus far have made restrictive assumptions about the design and selection rules followed. In order to address these shortcomings, we apply recent methodological advances to derive the uniformly minimum variance conditionally unbiased estimator for two-stage seamless phase II/III trials. Our framework allows for the precision of the treatment arm estimates to take arbitrary values, can be utilised for all treatments that are taken forward to phase III and is applicable when the decision to select or drop treatment arms is driven by a multiplicity-adjusted hypothesis testing procedure. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. PMID:27103068

  5. Unbiased estimation in seamless phase II/III trials with unequal treatment effect variances and hypothesis-driven selection rules.

    PubMed

    Robertson, David S; Prevost, A Toby; Bowden, Jack

    2016-09-30

    Seamless phase II/III clinical trials offer an efficient way to select an experimental treatment and perform confirmatory analysis within a single trial. However, combining the data from both stages in the final analysis can induce bias into the estimates of treatment effects. Methods for bias adjustment developed thus far have made restrictive assumptions about the design and selection rules followed. In order to address these shortcomings, we apply recent methodological advances to derive the uniformly minimum variance conditionally unbiased estimator for two-stage seamless phase II/III trials. Our framework allows for the precision of the treatment arm estimates to take arbitrary values, can be utilised for all treatments that are taken forward to phase III and is applicable when the decision to select or drop treatment arms is driven by a multiplicity-adjusted hypothesis testing procedure. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  6. How to Estimate and Interpret Various Effect Sizes

    ERIC Educational Resources Information Center

    Vacha-Haase, Tammi; Thompson, Bruce

    2004-01-01

    The present article presents a tutorial on how to estimate and interpret various effect sizes. The 5th edition of the Publication Manual of the American Psychological Association (2001) described the failure to report effect sizes as a "defect" (p. 5), and 23 journals have published author guidelines requiring effect size reporting. Although…

  7. School adjustment in sixth graders: parenting transitions, family climate, and peer norm effects.

    PubMed

    Kurdek, L A; Fine, M A; Sinclair, R J

    1995-04-01

    This study examined whether sixth graders' (mean age = 11.86 years) adjustment to the school context (assessed by grades, achievement scores, and disruptive behavior) was affected by factors from both the family context (represented by students' reports of the number of parenting transitions experienced as well as current levels of supervision, acceptance, autonomy granting, and conflict in the family) and the peer context (represented by students' perceptions of peer norms supporting academic excellence). School adjustment was related to the number of parenting transitions experienced, family climate, and peer norms as well as to higher-order relations involving family climate and peer norms such that (a) high grade point averages occurred at only moderate levels of family supervision, (b) achievement scores were positively related to supervision at only low levels of family autonomy granting, and (c) grade point average was positively related to peer norms at only high levels of family acceptance.

  8. Post-error adjustments and ADHD symptoms in adults: The effect of laterality and state regulation.

    PubMed

    Mohamed, Saleh M H; Börger, Norbert A; Geuze, Reint H; van der Meere, Jaap J

    2016-10-01

    Evidence is accumulating that individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) do not adjust their responses after committing errors. Post-error response adjustments are taken to reflect, among others, error monitoring that is essential for learning, flexible behavioural adaptation, and achieving future goals. Many behavioural studies have suggested that atypical lateral brain functions and difficulties in allocating effort to protect performance against stressors (i.e., state regulation) are key factors in ADHD. Whether these factors contribute to the absence of post-error response adjustments in ADHD is unknown. The aim of the present study is to investigate the contribution of the left and right hemispheres and the deficiency in effort allocation to deviant post-error processing in adults with high ADHD symptoms. From a pool of 87 university students, two groups were formed: a group with higher (n=30) and a group with lower (n=26) scores on the ADHD index subscale of the Conners' Adult ADHD Rating Scales. The groups performed a lateralized lexical decision task with a fast and slower stimulus presentation rate. Post-error slowing and post-error response accuracy to stimuli presented in the left and right visual field were measured in each stimulus presentation rate. Results indicated that subjects with the lower ADHD scores slowed down and improved their response accuracy after errors, especially when stimuli were presented in the right visual field at the slower rate. In contrast, subjects with the higher ADHD scores showed no post-error adjustments. Results suggest that during lexical decision performance, impaired error processing in adults with ADHD is associated with affected ability of the left hemisphere to compensate for errors, especially when extra effort allocation is needed to meet task demands.

  9. Post-error adjustments and ADHD symptoms in adults: The effect of laterality and state regulation.

    PubMed

    Mohamed, Saleh M H; Börger, Norbert A; Geuze, Reint H; van der Meere, Jaap J

    2016-10-01

    Evidence is accumulating that individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) do not adjust their responses after committing errors. Post-error response adjustments are taken to reflect, among others, error monitoring that is essential for learning, flexible behavioural adaptation, and achieving future goals. Many behavioural studies have suggested that atypical lateral brain functions and difficulties in allocating effort to protect performance against stressors (i.e., state regulation) are key factors in ADHD. Whether these factors contribute to the absence of post-error response adjustments in ADHD is unknown. The aim of the present study is to investigate the contribution of the left and right hemispheres and the deficiency in effort allocation to deviant post-error processing in adults with high ADHD symptoms. From a pool of 87 university students, two groups were formed: a group with higher (n=30) and a group with lower (n=26) scores on the ADHD index subscale of the Conners' Adult ADHD Rating Scales. The groups performed a lateralized lexical decision task with a fast and slower stimulus presentation rate. Post-error slowing and post-error response accuracy to stimuli presented in the left and right visual field were measured in each stimulus presentation rate. Results indicated that subjects with the lower ADHD scores slowed down and improved their response accuracy after errors, especially when stimuli were presented in the right visual field at the slower rate. In contrast, subjects with the higher ADHD scores showed no post-error adjustments. Results suggest that during lexical decision performance, impaired error processing in adults with ADHD is associated with affected ability of the left hemisphere to compensate for errors, especially when extra effort allocation is needed to meet task demands. PMID:27429094

  10. Effect size estimates: current use, calculations, and interpretation.

    PubMed

    Fritz, Catherine O; Morris, Peter E; Richler, Jennifer J

    2012-02-01

    The Publication Manual of the American Psychological Association (American Psychological Association, 2001, American Psychological Association, 2010) calls for the reporting of effect sizes and their confidence intervals. Estimates of effect size are useful for determining the practical or theoretical importance of an effect, the relative contributions of factors, and the power of an analysis. We surveyed articles published in 2009 and 2010 in the Journal of Experimental Psychology: General, noting the statistical analyses reported and the associated reporting of effect size estimates. Effect sizes were reported for fewer than half of the analyses; no article reported a confidence interval for an effect size. The most often reported analysis was analysis of variance, and almost half of these reports were not accompanied by effect sizes. Partial η2 was the most commonly reported effect size estimate for analysis of variance. For t tests, 2/3 of the articles did not report an associated effect size estimate; Cohen's d was the most often reported. We provide a straightforward guide to understanding, selecting, calculating, and interpreting effect sizes for many types of data and to methods for calculating effect size confidence intervals and power analysis.

  11. Effect size estimates: current use, calculations, and interpretation.

    PubMed

    Fritz, Catherine O; Morris, Peter E; Richler, Jennifer J

    2012-02-01

    The Publication Manual of the American Psychological Association (American Psychological Association, 2001, American Psychological Association, 2010) calls for the reporting of effect sizes and their confidence intervals. Estimates of effect size are useful for determining the practical or theoretical importance of an effect, the relative contributions of factors, and the power of an analysis. We surveyed articles published in 2009 and 2010 in the Journal of Experimental Psychology: General, noting the statistical analyses reported and the associated reporting of effect size estimates. Effect sizes were reported for fewer than half of the analyses; no article reported a confidence interval for an effect size. The most often reported analysis was analysis of variance, and almost half of these reports were not accompanied by effect sizes. Partial η2 was the most commonly reported effect size estimate for analysis of variance. For t tests, 2/3 of the articles did not report an associated effect size estimate; Cohen's d was the most often reported. We provide a straightforward guide to understanding, selecting, calculating, and interpreting effect sizes for many types of data and to methods for calculating effect size confidence intervals and power analysis. PMID:21823805

  12. Effects of pelvic adjustment on pelvic posture and angles of the lower limb joints during walking in female university students

    PubMed Central

    Cho, Misuk

    2016-01-01

    [Purpose] This study investigated the effects of pelvic adjustment on pelvic posture and lower limb joint angles during walking in female university students. [Subjects] Thirty healthy female university students were randomly assigned to an experimental group (pelvic adjustment group, n = 15) and a control group (stretching group, n = 15). [Methods] Pelvic adjustment was performed three times on the experimental group. The control group performed three sets of pelvic muscle stretching for 15 minutes. A back mapper and motion analysis equipment were used to measure pelvic posture and angles of lower limb joints for the experimental and control group. [Results] The values obtained before and after the intervention were compared. For the experimental group, the results were significantly different in terms of reduced differences in hip flexion between the left and right hips and in knee abduction between the left and right knees. Differences in pelvic position and pelvic torsion were also found in the experimental group. No significant differences in the control group were identified. [Conclusion] Pelvic adjustment affects pelvic position and torsion and this enhancement to pelvic stability decreases hip flexion and knee abduction during walking. PMID:27190468

  13. Psychological preparation for surgery pediatric patients: the effects on children's and parents' stress responses and adjustment.

    PubMed

    Visintainer, M A; Wolfer, J A

    1975-08-01

    This clinical experiment tested variations of psychological preparation and supportive care designed to increase the adjustment of children (and their parents) hospitalized for elective surgery. Eighty-four children, aged 3 to 12, admitted for tonsillectomies were randomly assigned to one of three treatment conditions or to a control group: (1) a combination of systematic preparation, rehearsal, and supportive care conducted prior to each stressful procedure; (2) a single-session preparation conducted after admission, and (3) consistent supportive care given by one nurse at the same points as in the first condition, but including no systematic preparation or rehearsal. The children's hospital adjustment was measured by blind ratings of behavioral upset and cooperation during the blood test, medication injection, transport to surgery, induction, and postoperative fluid intake and by recovery room medications and pulse rates and time to first voiding. Post-hospital adjustment was assessed with Vernon et al.'s Post Hospital Behavior Inventory. Parent outcome measures included self-ratings for anxiety and satisfaction with information and care. As hypothesized, the results demonstrated that children who received condition one showed significantly less upset and more cooperation and their parents reported significantly greater satisfaction and less anxiety than did children or parents in the other groups. Younger children were significantly more upset and less cooperative than older children.

  14. Mathematical procedure to adjust for the healthy worker effect: the case of firefighting, diabetes, and heart disease.

    PubMed

    Choi, B C

    2001-12-01

    This article presents a mathematical procedure to adjust for one component of the healthy worker effect (HWE), namely, the healthy hired effect, on diabetes in the case of firefighting and heart disease. Three examples from real studies are given to illustrate, step-by-step, the application of the mathematical procedure. The mathematical procedure can be applied to adjust for other components of the HWE (e.g., the low-risk hired effect on obese individuals and smokers). In such cases, additional information will be needed to use the mathematical procedure. Results of applying the mathematical procedure in the case of firefighting and heart disease revealed the rather unexpected results that adjusting for diabetes selection on hiring leads to only a 3% to 9% increase in the magnitude of ratio statistics such as the standardized mortality ratio. It might be argued that the HWE from one component such as the healthy hired effect on diabetes might be small, but together with other components, the HWE might be large. Further investigation will be needed to support this argument.

  15. Ultrasound imaging velocimetry: effect of beam sweeping on velocity estimation.

    PubMed

    Zhou, Bin; Fraser, Katharine H; Poelma, Christian; Mari, Jean-Martial; Eckersley, Robert J; Weinberg, Peter D; Tang, Meng-Xing

    2013-09-01

    As an emerging flow-mapping tool that can penetrate deep into optically opaque media such as human tissue, ultrasound imaging velocimetry has promise in various clinical applications. Previous studies have shown that errors occur in velocity estimation, but the causes have not been well characterised. In this study, the error in velocity estimation resulting from ultrasound beam sweeping in image acquisition is quantitatively investigated. The effects on velocity estimation of the speed and direction of beam sweeping relative to those of the flow are studied through simulation and experiment. The results indicate that a relative error in velocity estimation of up to 20% can be expected. Correction methods to reduce the errors under steady flow conditions are proposed and evaluated. Errors in flow estimation under unsteady flow are discussed.

  16. Colored noise effects on batch attitude accuracy estimates

    NASA Technical Reports Server (NTRS)

    Bilanow, Stephen

    1991-01-01

    The effects of colored noise on the accuracy of batch least squares parameter estimates with applications to attitude determination cases are investigated. The standard approaches used for estimating the accuracy of a computed attitude commonly assume uncorrelated (white) measurement noise, while in actual flight experience measurement noise often contains significant time correlations and thus is colored. For example, horizon scanner measurements from low Earth orbit were observed to show correlations over many minutes in response to large scale atmospheric phenomena. A general approach to the analysis of the effects of colored noise is investigated, and interpretation of the resulting equations provides insight into the effects of any particular noise color and the worst case noise coloring for any particular parameter estimate. It is shown that for certain cases, the effects of relatively short term correlations can be accommodated by a simple correction factor. The errors in the predicted accuracy assuming white noise and the reduced accuracy due to the suboptimal nature of estimators that do not take into account the noise color characteristics are discussed. The appearance of a variety of sample noise color characteristics are demonstrated through simulation, and their effects are discussed for sample estimation cases. Based on the analysis, options for dealing with the effects of colored noise are discussed.

  17. Studying the effects of dietary body weight-adjusted acute tryptophan depletion on punishment-related behavioral inhibition

    PubMed Central

    Gaber, Tilman J.; Dingerkus, Vita L. S.; Crockett, Molly J.; Bubenzer-Busch, Sarah; Helmbold, Katrin; Sánchez, Cristina L.; Dahmen, Brigitte; Herpertz-Dahlmann, Beate; Zepf, Florian D.

    2015-01-01

    Background Alterations in serotonergic (5-HT) neurotransmission are thought to play a decisive role in affective disorders and impulse control. Objective This study aims to reproduce and extend previous findings on the effects of acute tryptophan depletion (ATD) and subsequently diminished central 5-HT synthesis in a reinforced categorization task using a refined body weight–adjusted depletion protocol. Design Twenty-four young healthy adults (12 females, mean age [SD]=25.3 [2.1] years) were subjected to a double-blind within-subject crossover design. Each subject was administered both an ATD challenge and a balanced amino acid load (BAL) in two separate sessions in randomized order. Punishment-related behavioral inhibition was assessed using a forced choice go/no-go task that incorporated a variable payoff schedule. Results Administration of ATD resulted in significant reductions in TRP measured in peripheral blood samples, indicating reductions of TRP influx across the blood–brain barrier and related brain 5-HT synthesis. Overall accuracy and response time performance were improved after ATD administration. The ability to adjust behavioral responses to aversive outcome magnitudes and behavioral adjustments following error contingent punishment remained intact after decreased brain 5-HT synthesis. A previously observed dissociation effect of ATD on punishment-induced inhibition was not observed. Conclusions Our results suggest that neurodietary challenges with ATD Moja–De have no detrimental effects on task performance and punishment-related inhibition in healthy adults. PMID:26268708

  18. Effects of sample size on KERNEL home range estimates

    USGS Publications Warehouse

    Seaman, D.E.; Millspaugh, J.J.; Kernohan, Brian J.; Brundige, Gary C.; Raedeke, Kenneth J.; Gitzen, Robert A.

    1999-01-01

    Kernel methods for estimating home range are being used increasingly in wildlife research, but the effect of sample size on their accuracy is not known. We used computer simulations of 10-200 points/home range and compared accuracy of home range estimates produced by fixed and adaptive kernels with the reference (REF) and least-squares cross-validation (LSCV) methods for determining the amount of smoothing. Simulated home ranges varied from simple to complex shapes created by mixing bivariate normal distributions. We used the size of the 95% home range area and the relative mean squared error of the surface fit to assess the accuracy of the kernel home range estimates. For both measures, the bias and variance approached an asymptote at about 50 observations/home range. The fixed kernel with smoothing selected by LSCV provided the least-biased estimates of the 95% home range area. All kernel methods produced similar surface fit for most simulations, but the fixed kernel with LSCV had the lowest frequency and magnitude of very poor estimates. We reviewed 101 papers published in The Journal of Wildlife Management (JWM) between 1980 and 1997 that estimated animal home ranges. A minority of these papers used nonparametric utilization distribution (UD) estimators, and most did not adequately report sample sizes. We recommend that home range studies using kernel estimates use LSCV to determine the amount of smoothing, obtain a minimum of 30 observations per animal (but preferably a?Y50), and report sample sizes in published results.

  19. Estimating the effectiveness of further sampling in species inventories

    USGS Publications Warehouse

    Keating, K.A.; Quinn, J.F.; Ivie, M.A.; Ivie, L.L.

    1998-01-01

    Estimators of the number of additional species expected in the next ??n samples offer a potentially important tool for improving cost-effectiveness of species inventories but are largely untested. We used Monte Carlo methods to compare 11 such estimators, across a range of community structures and sampling regimes, and validated our results, where possible, using empirical data from vascular plant and beetle inventories from Glacier National Park, Montana, USA. We found that B. Efron and R. Thisted's 1976 negative binomial estimator was most robust to differences in community structure and that it was among the most accurate estimators when sampling was from model communities with structures resembling the large, heterogeneous communities that are the likely targets of major inventory efforts. Other estimators may be preferred under specific conditions, however. For example, when sampling was from model communities with highly even species-abundance distributions, estimates based on the Michaelis-Menten model were most accurate; when sampling was from moderately even model communities with S=10 species or communities with highly uneven species-abundance distributions, estimates based on Gleason's (1922) species-area model were most accurate. We suggest that use of such methods in species inventories can help improve cost-effectiveness by providing an objective basis for redirecting sampling to more-productive sites, methods, or time periods as the expectation of detecting additional species becomes unacceptably low.

  20. Technical Note: Estimating Aerosol Effects on Cloud Radiative Forcing

    SciTech Connect

    Ghan, Steven J.

    2013-10-09

    Estimating anthropogenic aerosol effects on the planetary energy balance through the aerosol influence on clouds using the difference in cloud radiative forcing from simulations with and without anthropogenic emissions produces estimates that are positively biased. A more representative method is suggested using the difference in cloud radiative forcing calculated with aerosol radiative effects neglected. The method also yields an aerosol radiative forcing decomposition that includes a term quantifying the impact of changes in surface albedo. The method requires only two additional diagnostic calculations: the whole-sky and clear-sky top-of-atmosphere radiative flux with aerosol radiative effects neglected.

  1. Effect of Second-phase Particles on Static Adjustment of Calcite Grain Boundaries in Carbonate Mylonites

    NASA Astrophysics Data System (ADS)

    Ree, J.; Lee, S.; Jung, H.

    2010-12-01

    Static adjustment of grain boundaries during the waning stage of deformation with sustained heat (e.g. at the end of an orogeny) has not been studied much, although it is important for the interpretation of microstructural status during the main stage of deformation. We report here that static adjustment of calcite grain boundaries is dependent on second-phase particles in carbonate mylonites from the Geounri Shear Zone in the Taebaeksan Basin of South Korea. The carbonate mylonites consist of relic (porphyroclastic) calcites (120-400 μm) and dynamically recrystallized calcites (30-35 μm) with second-phase particles (15-20 μm) of quartz and phyllosilicates. Both calcite grains contain mechanical twins and the twins are wider (10-20 μm thick) in the relic calcites than in the dynamically recrystallized ones (1-3 μm thick). In the layers of carbonate mylonite with less than 3% of second phases, grain boundaries of calcites are straight with triple junctions. In contrast, calcite grain boundaries are lobate to wavy in the layers with more than 3% of second phases, suggesting dynamic grain boundary migration. Calcite grains in both layers show a strong lattice preferred orientation indicating dominant slip system of basal with minor one of rhomb . We interpret that the foam texture of calcite in the mylonite layers with less than 3% of second phases was produced during the waning stage of the main deformation with a sustained heat since both syntectonic and posttectonic chloritoid porphyroblasts occur in adjacent phyllonite layers in the shear zone. 3% volume fraction of second-phase particles might be a critical value above which deformation microstructures of the main phase were ‘frozen’ without static adjustment in our carbonate mylonites.

  2. Adjusting for Network Size and Composition Effects in Exponential-Family Random Graph Models.

    PubMed

    Krivitsky, Pavel N; Handcock, Mark S; Morris, Martina

    2011-07-01

    Exponential-family random graph models (ERGMs) provide a principled way to model and simulate features common in human social networks, such as propensities for homophily and friend-of-a-friend triad closure. We show that, without adjustment, ERGMs preserve density as network size increases. Density invariance is often not appropriate for social networks. We suggest a simple modification based on an offset which instead preserves the mean degree and accommodates changes in network composition asymptotically. We demonstrate that this approach allows ERGMs to be applied to the important situation of egocentrically sampled data. We analyze data from the National Health and Social Life Survey (NHSLS). PMID:21691424

  3. Adjusting for Network Size and Composition Effects in Exponential-Family Random Graph Models

    PubMed Central

    Krivitsky, Pavel N.; Handcock, Mark S.; Morris, Martina

    2011-01-01

    Exponential-family random graph models (ERGMs) provide a principled way to model and simulate features common in human social networks, such as propensities for homophily and friend-of-a-friend triad closure. We show that, without adjustment, ERGMs preserve density as network size increases. Density invariance is often not appropriate for social networks. We suggest a simple modification based on an offset which instead preserves the mean degree and accommodates changes in network composition asymptotically. We demonstrate that this approach allows ERGMs to be applied to the important situation of egocentrically sampled data. We analyze data from the National Health and Social Life Survey (NHSLS). PMID:21691424

  4. Improved Estimation of Human Lipoprotein Kinetics with Mixed Effects Models

    PubMed Central

    Berglund, Martin; Adiels, Martin; Taskinen, Marja-Riitta; Borén, Jan; Wennberg, Bernt

    2015-01-01

    Context Mathematical models may help the analysis of biological systems by providing estimates of otherwise un-measurable quantities such as concentrations and fluxes. The variability in such systems makes it difficult to translate individual characteristics to group behavior. Mixed effects models offer a tool to simultaneously assess individual and population behavior from experimental data. Lipoproteins and plasma lipids are key mediators for cardiovascular disease in metabolic disorders such as diabetes mellitus type 2. By the use of mathematical models and tracer experiments fluxes and production rates of lipoproteins may be estimated. Results We developed a mixed effects model to study lipoprotein kinetics in a data set of 15 healthy individuals and 15 patients with type 2 diabetes. We compare the traditional and the mixed effects approach in terms of group estimates at various sample and data set sizes. Conclusion We conclude that the mixed effects approach provided better estimates using the full data set as well as with both sparse and truncated data sets. Sample size estimates showed that to compare lipoprotein secretion the mixed effects approach needed almost half the sample size as the traditional method. PMID:26422201

  5. A regional classification scheme for estimating reference water quality in streams using land-use-adjusted spatial regression-tree analysis

    USGS Publications Warehouse

    Robertson, D.M.; Saad, D.A.; Heisey, D.M.

    2006-01-01

    Various approaches are used to subdivide large areas into regions containing streams that have similar reference or background water quality and that respond similarly to different factors. For many applications, such as establishing reference conditions, it is preferable to use physical characteristics that are not affected by human activities to delineate these regions. However, most approaches, such as ecoregion classifications, rely on land use to delineate regions or have difficulties compensating for the effects of land use. Land use not only directly affects water quality, but it is often correlated with the factors used to define the regions. In this article, we describe modifications to SPARTA (spatial regression-tree analysis), a relatively new approach applied to water-quality and environmental characteristic data to delineate zones with similar factors affecting water quality. In this modified approach, land-use-adjusted (residualized) water quality and environmental characteristics are computed for each site. Regression-tree analysis is applied to the residualized data to determine the most statistically important environmental characteristics describing the distribution of a specific water-quality constituent. Geographic information for small basins throughout the study area is then used to subdivide the area into relatively homogeneous environmental water-quality zones. For each zone, commonly used approaches are subsequently used to define its reference water quality and how its water quality responds to changes in land use. SPARTA is used to delineate zones of similar reference concentrations of total phosphorus and suspended sediment throughout the upper Midwestern part of the United States. ?? 2006 Springer Science+Business Media, Inc.

  6. Effects of unilateral stroke on multi-finger synergies and their feed-forward adjustments.

    PubMed

    Jo, H J; Maenza, C; Good, D C; Huang, X; Park, J; Sainburg, R L; Latash, M L

    2016-04-01

    We explored the changes in multi-finger synergies in patients after a single cortical stroke with mild motor impairments. We hypothesized that both synergy indices and anticipatory synergy adjustments prior to the initiation of a self-paced quick action would be diminished in the patients compared to age-matched controls. The patients with history of cortical stroke, and age-matched controls (n=12 in each group) performed one-finger and multi-finger accurate force production tasks involving both steady-state and quick force pulse production. Finger interdependence (enslaving) and multi-finger synergies stabilizing total force were quantified. The stroke patients showed lower maximal finger forces, in particular in the contralesional hand, which also showed increased enslaving indices. Multi-finger synergies during steady-state force production were, however, unchanged after stroke. In contrast, a drop in the synergy index prior to the force pulse generation was significantly delayed in the stroke patients. Our results show that mild cortical stroke leads to no significant changes in multifinger synergies, but there is impairment in feed-forward adjustments of the synergies prior to a quick action, a drop in the maximal force production, and an increase in enslaving. We conclude that studies of synergies reveal two aspects of synergic control differentially affected by cortical stroke. PMID:26828408

  7. Effects of Hoods and Flame-Retardant Fabrics on WBGT Clothing Adjustment Factors.

    PubMed

    Ashley, Candi D; Bernard, Thomas E

    2008-01-01

    Personal protective clothing (PPC) may include hoods and flame-retardant (FR) fabrics that may affect heat transfer and, thus, the critical wet bulb globe temperature (WBGT crit) to maintain thermal equilibrium. The purpose of this study was to compare the differences in WBGT crit for hooded vs. nonhooded versions of particle barrier and vapor barrier coveralls as well as for coveralls made of two flame-retardant fabrics (INDURA cotton and Nomex). Acclimated men (n = 11) and women (n = 4) walked on a treadmill in a climatic chamber at 180 W/m2 wearing four different ensembles: limited-use, particle barrier coveralls with and without a hood (Tyvek 1427), and limited-use vapor barrier coveralls with and without a hood (Tychem QC, polyethylene-coated Tyvek). Twelve of the participants wore one of two flame-retardant coveralls. All participants wore standard cotton clothing. Progressive exposure testing at 50% relative humidity (rh) was designed so that each subject established a physiological steady-state followed by a clear loss of thermal equilibrium. WBGT crit was the WBGT 5 min prior to a loss of thermal equilibrium. Hooded ensembles had a lower WBGT crit than the nonhooded ensembles. The difference suggested a clothing adjustment of 1 degrees C for hoods. There were no significant differences among the FR ensembles and cotton work cloths, and the proposed clothing adjustment for FR coveralls clothing is 0 degrees C. PMID:18041645

  8. The Effects of Misclassification Biases on Veteran Suicide Rate Estimates

    PubMed Central

    Kaplan, Mark S.; McFarland, Bentson H.

    2014-01-01

    Objectives. We assessed the impact that possible veteran suicide misclassification biases (i.e., inaccuracy in ascertainment of veteran status on the death certificate and misclassification of suicide as other manner of death) have on veteran suicide rate estimates. Methods. We obtained suicide mortality data from the 2003–2010 National Violent Death Reporting System and the 2003–2010 Department of Defense Casualty Analysis System. We derived population estimates from the 2003–2010 American Community Survey and 2003–2010 Department of Veterans Affairs data. We computed veteran and nonveteran suicide rates. Results. The results showed that suicide rates were minimally affected by the adjustment for the misclassification of current military personnel suicides as veterans. Moreover, combining suicides and deaths by injury of undetermined intent did not alter the conclusions. Conclusions. The National Violent Death Reporting System is a valid surveillance system for veteran suicide. However, more than half of younger (< 25 years) male and female suicides, labeled as veterans, were likely to have been current military personnel at the time of their death and misclassified on the death certificate. PMID:24228669

  9. MO-E-17A-08: Attenuation-Based Size Adjusted, Scanner-Independent Organ Dose Estimates for Head CT Exams: TG 204 for Head CT

    SciTech Connect

    McMillan, K; Bostani, M; Cagnon, C; McNitt-Gray, M; Zankl, M; DeMarco, J

    2014-06-15

    Purpose: AAPM Task Group 204 described size specific dose estimates (SSDE) for body scans. The purpose of this work is to use a similar approach to develop patient-specific, scanner-independent organ dose estimates for head CT exams using an attenuation-based size metric. Methods: For eight patient models from the GSF family of voxelized phantoms, dose to brain and lens of the eye was estimated using Monte Carlo simulations of contiguous axial scans for 64-slice MDCT scanners from four major manufacturers. Organ doses were normalized by scannerspecific 16 cm CTDIvol values and averaged across all scanners to obtain scanner-independent CTDIvol-to-organ-dose conversion coefficients for each patient model. Head size was measured at the first slice superior to the eyes; patient perimeter and effective diameter (ED) were measured directly from the GSF data. Because the GSF models use organ identification codes instead of Hounsfield units, water equivalent diameter (WED) was estimated indirectly. Using the image data from 42 patients ranging from 2 weeks old to adult, the perimeter, ED and WED size metrics were obtained and correlations between each metric were established. Applying these correlations to the GSF perimeter and ED measurements, WED was calculated for each model. The relationship between the various patient size metrics and CTDIvol-to-organ-dose conversion coefficients was then described. Results: The analysis of patient images demonstrated the correlation between WED and ED across a wide range of patient sizes. When applied to the GSF patient models, an exponential relationship between CTDIvol-to-organ-dose conversion coefficients and the WED size metric was observed with correlation coefficients of 0.93 and 0.77 for the brain and lens of the eye, respectively. Conclusion: Strong correlation exists between CTDIvol normalized brain dose and WED. For the lens of the eye, a lower correlation is observed, primarily due to surface dose variations. Funding

  10. Shaft adjuster

    DOEpatents

    Harry, H.H.

    1988-03-11

    Abstract and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus. 3 figs.

  11. Shaft adjuster

    DOEpatents

    Harry, Herbert H.

    1989-01-01

    Apparatus and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus.

  12. The effects of acoustic misclassification on cetacean species abundance estimation.

    PubMed

    Caillat, Marjolaine; Thomas, Len; Gillespie, Douglas

    2013-09-01

    To estimate the density or abundance of a cetacean species using acoustic detection data, it is necessary to correctly identify the species that are detected. Developing an automated species classifier with 100% correct classification rate for any species is likely to stay out of reach. It is therefore necessary to consider the effect of misidentified detections on the number of observed data and consequently on abundance or density estimation, and develop methods to cope with these misidentifications. If misclassification rates are known, it is possible to estimate the true numbers of detected calls without bias. However, misclassification and uncertainties in the level of misclassification increase the variance of the estimates. If the true numbers of calls from different species are similar, then a small amount of misclassification between species and a small amount of uncertainty around the classification probabilities does not have an overly detrimental effect on the overall variance. However, if there is a difference in the encounter rate between species calls and/or a large amount of uncertainty in misclassification rates, then the variance of the estimates becomes very large and this dramatically increases the variance of the final abundance estimate.

  13. Particular adaptations to potentially slippery surfaces: the effects of friction on consecutive postural adjustments (CPA).

    PubMed

    Memari, Sahel; Le Bozec, Serge; Bouisset, Simon

    2014-02-21

    This research deals with the postural adjustments that occur after the end of voluntary movement ("consecutive postural adjustments": CPAs). The influence of a potentially slippery surface on CPA characteristics was considered, with the aim of exploring more deeply the postural component of the task-movement. Seven male adults were asked to perform a single step, as quickly as possible, to their own footprint marked on the ground. A force plate measured the resultant reaction forces along the antero-posterior axis (R(x)) and the centre of pressure (COP) displacements along the antero-posterior and lateral axes (Xp and Yp). The velocity of the centre of gravity (COG) along the antero-posterior axis and the corresponding impulse (∫R(x)dt) were calculated; the peak velocity (termed "progression velocity": V(xG)) was measured. The required coefficient of friction (RCOF) along the progression axis (pμ(x)) was determined. Two materials, differing by their COF, were laid at foot contact (FC), providing a rough foot contact (RoFC), and a smooth foot contact (SmFC) considered to be potentially slippery. Two step lengths were also performed: a short step (SS) and a long step (LS). Finally, the subjects completed four series of ten steps each. These were preceded by preliminary trials, to allow them to acquire the necessary adaptation to experimental conditions. The antero-posterior force time course presented a positive phase, that included APAs ("anticipatory postural adjustments") and step execution (STEP), followed by a negative one, corresponding to CPAs. The backward impulse (CPI) was equal to the forward one (BPI), independently of friction and progression velocity. Moreover, V(xG) did not differ according to friction, but was faster when the step length was greater. Last CPA peak amplitudes (pCPA) were significantly greater and CPA durations (dCPA) shorter for RoFC and conversely for SmFC, contrary to APA. Finally, the results show a particular adaptation to the

  14. Estimated Short-Term Effects of Coarse Particles on Daily Mortality in Stockholm, Sweden

    PubMed Central

    Johansson, Christer; Forsberg, Bertil

    2011-01-01

    Background: Although serious health effects associated with particulate matter (PM) with aerodynamic diameter ≤ 10 μm (PM10) and ≤ 2.5 μm (PM2.5; fine fraction) are documented in many studies, the effects of coarse PM (PM2.5–10) are still under debate. Objective: In this study, we estimated the effects of short-term exposure of PM2.5–10 on daily mortality in Stockholm, Sweden. Method: We collected data on daily mortality for the years 2000 through 2008. Concentrations of PM10, PM2.5, ozone, and carbon monoxide were measured simultaneously in central Stockholm. We used additive Poisson regression models to examine the association between daily mortality and PM2.5–10 on the day of death and the day before. Effect estimates were adjusted for other pollutants (two-pollutant models) during different seasons. Results: We estimated a 1.68% increase [95% confidence interval (CI): 0.20%, 3.15%] in daily mortality per 10-μg/m3 increase in PM2.5–10 (single-pollutant model). The association with PM2.5–10 was stronger for November through May, when road dust is most important (1.69% increase; 95% CI: 0.21%, 3.17%), compared with the rest of the year (1.31% increase; 95% CI: –2.08%, 4.70%), although the difference was not statistically significant. When adjusted for other pollutants, particularly PM2.5, the effect estimates per 10 μg/m3 for PM2.5–10 decreased slightly but were still higher than corresponding effect estimates for PM2.5. Conclusions: Our analysis shows an increase in daily mortality associated with elevated urban background levels of PM2.5–10. Regulation of PM2.5–10 should be considered, along with actions to specifically reduce PM2.5–10 emissions, especially road dust suspension, in cities. PMID:22182596

  15. Does more accurate exposure prediction necessarily improve health effect estimates?

    PubMed

    Szpiro, Adam A; Paciorek, Christopher J; Sheppard, Lianne

    2011-09-01

    A unique challenge in air pollution cohort studies and similar applications in environmental epidemiology is that exposure is not measured directly at subjects' locations. Instead, pollution data from monitoring stations at some distance from the study subjects are used to predict exposures, and these predicted exposures are used to estimate the health effect parameter of interest. It is usually assumed that minimizing the error in predicting the true exposure will improve health effect estimation. We show in a simulation study that this is not always the case. We interpret our results in light of recently developed statistical theory for measurement error, and we discuss implications for the design and analysis of epidemiologic research.

  16. Locally efficient estimation of marginal treatment effects when outcomes are correlated: is the prize worth the chase?

    PubMed Central

    Stephens, Alisa J.; Tchetgen Tchetgen, Eric J.; De Gruttola, Victor

    2014-01-01

    Semiparametric methods have been developed to increase efficiency of inferences in randomized trials by incorporating baseline covariates. Locally efficient estimators of marginal treatment effects, which achieve minimum variance under an assumed model, are available for settings in which outcomes are independent. The value of the pursuit of locally efficient estimators in other settings, such as when outcomes are multivariate, is often debated. We derive and evaluate semiparametric locally efficient estimators of marginal mean treatment effects when outcomes are correlated; such outcomes occur in randomized studies with clustered or repeated-measures responses. The resulting estimating equations modify existing generalized estimating equations (GEE) by identifying the efficient score under a mean model for marginal effects when data contain baseline covariates. Locally efficient estimators are implemented for longitudinal data with continuous outcomes and clustered data with binary outcomes. Methods are illustrated through application to AIDS Clinical Trial Group Study 398, a longitudinal randomized clinical trial that compared the effects of various protease inhibitors in HIV-positive subjects who had experienced antiretroviral therapy failure. In addition, extensive simulation studies characterize settings in which locally efficient estimators result in efficiency gains over suboptimal estimators and assess their feasibility in practice. Clinical trials; Correlated outcomes; Covariate adjustment; Semiparametric efficiency PMID:24566369

  17. Adjusted peak-flow frequency estimates for selected streamflow-gaging stations in or near Montana based on data through water year 2011: Chapter D in Montana StreamStats

    USGS Publications Warehouse

    Sando, Steven K.; Sando, Roy; McCarthy, Peter M.; Dutton, DeAnn M.

    2016-04-05

    The climatic conditions of the specific time period during which peak-flow data were collected at a given streamflow-gaging station (hereinafter referred to as gaging station) can substantially affect how well the peak-flow frequency (hereinafter referred to as frequency) results represent long-term hydrologic conditions. Differences in the timing of the periods of record can result in substantial inconsistencies in frequency estimates for hydrologically similar gaging stations. Potential for inconsistency increases with decreasing peak-flow record length. The representativeness of the frequency estimates for a short-term gaging station can be adjusted by various methods including weighting the at-site results in association with frequency estimates from regional regression equations (RREs) by using the Weighted Independent Estimates (WIE) program. Also, for gaging stations that cannot be adjusted by using the WIE program because of regulation or drainage areas too large for application of RREs, frequency estimates might be improved by using record extension procedures, including a mixed-station analysis using the maintenance of variance type I (MOVE.1) procedure. The U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources and Conservation, completed a study to provide adjusted frequency estimates for selected gaging stations through water year 2011.The purpose of Chapter D of this Scientific Investigations Report is to present adjusted frequency estimates for 504 selected streamflow-gaging stations in or near Montana based on data through water year 2011. Estimates of peak-flow magnitudes for the 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities are reported. These annual exceedance probabilities correspond to the 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively.The at-site frequency estimates were

  18. Random effects and shrinkage estimation in capture-recapture models

    USGS Publications Warehouse

    Royle, J. Andrew; Link, W.A.

    2002-01-01

    We discuss the analysis of random effects in capture-recapture models, and outline Bayesian and frequentists approaches to their analysis. Under a normal model, random effects estimators derived from Bayesian or frequentist considerations have a common form as shrinkage estimators. We discuss some of the difficulties of analysing random effects using traditional methods, and argue that a Bayesian formulation provides a rigorous framework for dealing with these difficulties. In capture-recapture models, random effects may provide a parsimonious compromise between constant and completely time-dependent models for the parameters (e.g. survival probability). We consider application of random effects to band-recovery models, although the principles apply to more general situations, such as Cormack-Jolly-Seber models. We illustrate these ideas using a commonly analysed band recovery data set.

  19. Long-Term Quantitative Precipitation Estimates (QPE) at High Spatial and Temporal Resolution over CONUS: Bias-Adjustment of the Radar-Only National Mosaic and Multi-sensor QPE (NMQ/Q2) Precipitation Reanalysis (2001-2012)

    NASA Astrophysics Data System (ADS)

    Prat, Olivier; Nelson, Brian; Stevens, Scott; Seo, Dong-Jun; Kim, Beomgeun

    2015-04-01

    The processing of radar-only precipitation via the reanalysis from the National Mosaic and Multi-Sensor Quantitative (NMQ/Q2) based on the WSR-88D Next-generation Radar (NEXRAD) network over Continental United States (CONUS) is completed for the period covering from 2001 to 2012. This important milestone constitutes a unique opportunity to study precipitation processes at a 1-km spatial resolution for a 5-min temporal resolution. However, in order to be suitable for hydrological, meteorological and climatological applications, the radar-only product needs to be bias-adjusted and merged with in-situ rain gauge information. Several in-situ datasets are available to assess the biases of the radar-only product and to adjust for those biases to provide a multi-sensor QPE. The rain gauge networks that are used such as the Global Historical Climatology Network-Daily (GHCN-D), the Hydrometeorological Automated Data System (HADS), the Automated Surface Observing Systems (ASOS), and the Climate Reference Network (CRN), have different spatial density and temporal resolution. The challenges related to incorporating non-homogeneous networks over a vast area and for a long-term record are enormous. Among the challenges we are facing are the difficulties incorporating differing resolution and quality surface measurements to adjust gridded estimates of precipitation. Another challenge is the type of adjustment technique. The objective of this work is threefold. First, we investigate how the different in-situ networks can impact the precipitation estimates as a function of the spatial density, sensor type, and temporal resolution. Second, we assess conditional and un-conditional biases of the radar-only QPE for various time scales (daily, hourly, 5-min) using in-situ precipitation observations. Finally, after assessing the bias and applying reduction or elimination techniques, we are using a unique in-situ dataset merging the different RG networks (CRN, ASOS, HADS, GHCN-D) to

  20. The Effects of Backward Adjustable Thoracic Support in Wheelchair on Spinal Curvature and Back Muscle Activation for Elderly People

    PubMed Central

    Li, Chun-Ting; Chen, Yen-Nien; Chang, Chih-Han; Tsai, Kuen-Horng

    2014-01-01

    Objectives To investigate the effects of backward adjustable thoracic support on spinal curvature and back muscle activation during wheelchair sitting. Methods Twenty elderly people were recruited for this study. The backward adjustable thoracic support sitting posture was compared with the slumped, normal, and lumbar support sitting postures. Spinal curvatures (pelvic, lumbar, and thoracic angles) and muscle activations of 4 back muscles on both sides (maximal voluntary isometric contraction of the lumbar multifidus, lumbar erector spinae, iliocostalis lumborum pars thoracis, and thoracic erector spinae at T9) were measured and compared between the different sitting postures using one-way analysis of variance with repeated measures. Results The backward adjustable thoracic support sitting posture showed a relatively neutral pelvic tilt (−0.32±4.80°) when compared with the slumped (22.84±5.27°) and lumbar support (−8.97±3.31°) sitting postures (P<0.001), and showed relatively higher lumbar lordosis (−23.38±6.50°) when compared with the slumped (14.77±7.83°), normal (0.44±7.47°), and lumbar support (−16.76±4.77°) sitting postures (P<0.05). It also showed relatively lower back muscle activity when compared with the normal and lumbar support sitting postures (P<0.05). Conclusions The backward adjustable thoracic support sitting concept was suggested because it maintains a more neutral pelvic tilt, higher lumbar lordosis, and lower back muscle activation, which may help maintain a better sitting posture and reduce the risk of back pain. PMID:25480152

  1. Estimating a treatment effect from multidimensional longitudinal data.

    PubMed

    Gray, S M; Brookmeyer, R

    1998-09-01

    Multidimensional longitudinal data result when researchers measure an outcome through time that is quantified by many different response variables. These response variables are often defined on different numerical scales. The objective of this paper is to present a method to summarize and estimate an overall treatment effect from this type of longitudinal data. A regression model is proposed that assumes the treatment effect can be parameterized as an acceleration or deceleration of the time scale of each response variable's trajectory. Generalized estimating equations are used to estimate the model parameters. Cognitive and functional ability data from Alzheimer's disease patients and quality of life data from an AIDS clinical trial are used to illustrate the model.

  2. Individual increase in inbreeding allows estimating effective sizes from pedigrees

    PubMed Central

    Gutiérrez, Juan Pablo; Cervantes, Isabel; Molina, Antonio; Valera, Mercedes; Goyache, Félix

    2008-01-01

    We present here a simple approach to obtain reliable estimates of the effective population size in real world populations via the computation of the increase in inbreeding for each individual (delta Fi) in a given population. The values of delta Fi are computed as t-root of 1 - (1 - Fi) where Fi is the inbreeding coefficient and t is the equivalent complete generations for each individual. The values of delta F computed for a pre-defined reference subset can be averaged and used to estimate effective size. A standard error of this estimate of Ne can be further computed from the standard deviation of the individual increase in inbreeding. The methodology is demonstrated by applying it to several simulated examples and to a real pedigree in which other methodologies fail when considering reference subpopulations. The main characteristics of the approach and its possible use are discussed both for predictive purposes and for analyzing genealogies. PMID:18558071

  3. Effects of measurement error on estimating biological half-life

    SciTech Connect

    Caudill, S.P.; Pirkle, J.L.; Michalek, J.E. )

    1992-10-01

    Direct computation of the observed biological half-life of a toxic compound in a person can lead to an undefined estimate when subsequent concentration measurements are greater than or equal to previous measurements. The likelihood of such an occurrence depends upon the length of time between measurements and the variance (intra-subject biological and inter-sample analytical) associated with the measurements. If the compound is lipophilic the subject's percentage of body fat at the times of measurement can also affect this likelihood. We present formulas for computing a model-predicted half-life estimate and its variance; and we derive expressions for the effect of sample size, measurement error, time between measurements, and any relevant covariates on the variability in model-predicted half-life estimates. We also use statistical modeling to estimate the probability of obtaining an undefined half-life estimate and to compute the expected number of undefined half-life estimates for a sample from a study population. Finally, we illustrate our methods using data from a study of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure among 36 members of Operation Ranch Hand, the Air Force unit responsible for the aerial spraying of Agent Orange in Vietnam.

  4. A Practical Method of Policy Analysis by Estimating Effect Size

    ERIC Educational Resources Information Center

    Phelps, James L.

    2011-01-01

    The previous articles on class size and other productivity research paint a complex and confusing picture of the relationship between policy variables and student achievement. Missing is a conceptual scheme capable of combining the seemingly unrelated research and dissimilar estimates of effect size into a unified structure for policy analysis and…

  5. Assumptions of Value-Added Models for Estimating School Effects

    ERIC Educational Resources Information Center

    Reardon, Sean F.; Raudenbush, Stephen W.

    2009-01-01

    The ability of school (or teacher) value-added models to provide unbiased estimates of school (or teacher) effects rests on a set of assumptions. In this article, we identify six assumptions that are required so that the estimands of such models are well defined and the models are able to recover the desired parameters from observable data. These…

  6. Examining the Relationship between Heavy Alcohol Use and Assaults: With Adjustment for the Effects of Unmeasured Confounders

    PubMed Central

    Liang, Wenbin; Chikritzhs, Tanya

    2015-01-01

    Background. Experimental studies suggest that alcohol can lead to aggression in laboratory settings; however, it is impossible to test the causal relationship between alcohol use and real-life violence among humans in randomized clinical trials. Objectives. (i) To examine the relationship between heavy alcohol use and assaults in a population based study; (ii) to demonstrate the proxy outcome method, as a means of controlling the effects of unknown/unmeasured confounders in observational studies. Methods. This study used data collected from three waves of the National Survey on Drug Use and Health (NSDUH). The effects of heavy alcohol use on assault were measured using multivariable logistic regressions in conjunction with the proxy outcome method. Results. Application of the proxy outcome method indicated that effect sizes of heavy alcohol use on the risk of assault were overestimated in the standard models. After adjusting for the effects of unknown/unmeasured confounders, the risk of assault remained 43% and 63% higher (P < 0.05) among participants who consumed 5+ drinks/day for 5–8 days/month and 9–30 days/month, respectively. Conclusions. Even after adjustment for unknown/unmeasured confounders the association between heavy alcohol use and risk of violence remained significant. These findings support the hypothesis that heavy alcohol use can cause violence. PMID:26380283

  7. Multiple trials may yield exaggerated effect size estimates.

    PubMed

    Brand, Andrew; Bradley, Michael T; Best, Lisa A; Stoica, George

    2011-01-01

    Published psychological research attempting to support the existence of small and medium effect sizes may not have enough participants to do so accurately, and thus, repeated trials or the use of multiple items may be used in an attempt to obtain significance. Through a series of Monte-Carlo simulations, this article describes the results of multiple trials or items on effect size estimates when the averages and aggregates of a dependent measure are analyzed. The simulations revealed a large increase in observed effect size estimates when the numbers of trials or items in an experiment were increased. Overestimation effects are mitigated by correlations between trials or items, but remain substantial in some cases. Some concepts, such as a P300 wave or a test score, are best defined as a composite of measures. Troubles may arise in more exploratory research where the interrelations among trials or items may not be well described. PMID:21404946

  8. Effects of the history of adoption in the emotional adjustment of adopted adolescents.

    PubMed

    Reppold, Caroline Tozzi; Hutz, Claudio Simon

    2009-11-01

    Since the decade of 1980, the model of stress and coping proposed for the assessment of vulnerability of adoptive families emphasizes that the emotional adjustment of those adopted is moderated by variables such as institutionalization, the manner and age at which the adoption was revealed, the change of first name, and the contact with the biological family. The objective of this study was to investigate the relationship of these variables to the perceived parenting style, mood, and self-esteem of the adopted adolescents. Participants in the study were 68 adolescents, between the ages of 14 and 15, adopted during infancy through judicial channels. The adolescents responded to a questionnaire about the history of adoption and to scales of Parenting Styles, Depression and Self-esteem. The main results indicated that the late revelation of adoption and the change of the first name are connected to higher levels of depression and low self-esteem and to more frequent perceptions of negligent or authoritarian parenting style. The contact with the biological family was frequently mentioned among those who perceived their parents as authoritative and presented the best indicator of mood and self-esteem. These findings were discussed in light of the necessity for multidisciplinary actions which can improve the psychological adaptation of the adopting families. PMID:19899647

  9. A Cost-Effective Fluorescence Mini-Microscope with Adjustable Magnifications for Biomedical Applications

    PubMed Central

    Zhang, Yu Shrike; Ribas, João; Nadhman, Akhtar; Aleman, Julio; Selimović, Šeila; Lesher-Perez, Sasha Cai; Wang, Ting; Manoharan, Vijayan; Shin, Su-Ryon; Damilano, Alessia; Annabi, Nasim; Dokmeci, Mehmet Remzi; Takayama, Shuichi; Khademhosseini, Ali

    2015-01-01

    We have designed and fabricated a miniature microscope from off-the-shelf components and webcam, with built-in fluorescence capability for biomedical applications. The mini-microscope was able to detect both biochemical parameters such as cell/tissue viability (e.g. Live/Dead assay), and biophysical properties of the microenvironment such as oxygen levels in microfabricated tissues based on an oxygen-sensitive fluorescent dye. This mini-microscope has adjustable magnifications from 8-60X, achieves a resolution as high as <2 μm, and possesses a long working distance of 4.5 mm (at a magnification of 8X). The mini-microscope was able to chronologically monitor cell migration and analyze beating of microfluidic liver and cardiac bioreactors in real time, respectively. The mini-microscope system is cheap, and its modularity allows convenient integration with a wide variety of pre-existing platforms including but not limited to, cell culture plates, microfluidic devices, and organs-on-a-chip systems. Therefore, we envision its widespread applications in cell biology, tissue engineering, biosensing, microfluidics, and organs-on-chips, which can potentially replace conventional bench-top microscopy where long-term in situ and large-scale imaging/analysis is required. PMID:26282117

  10. On the gravity and geoid effects of glacial isostatic adjustment in Fennoscandia - a short note

    NASA Astrophysics Data System (ADS)

    Sjöberg, L. E.

    2016-02-01

    Many geoscientists argue that there is a gravity low of 10-30 mGal in Fennoscandia as a remaining fingerprint of the last ice age and load, both vanished about 10 kyr ago. However, the extraction of the gravity signal related with Glacial Isostatic Adjustment (GIA) is complicated by the fact that the total gravity field is caused by many significant density distributions in the Earth. Here we recall a methodology originating with A. Bjerhammar 35 years ago, that emphasizes that the present land uplift phenomenon mainly occurs in the region thatwas covered by the ice cap, and it is highly correlated with the spectral window of degrees 10-22 of the global gravity field, whose lower limit fairly well corresponds to the wavelength that agrees with the size of the region. This implies that, although in principle the GIA is a global phenomenon, the geoid and gravity lows as well as the land upheaval in Fennoscandia are typically regional phenomena that cannot be seen in a global correlation study as it is blurred by many irrelevant gravity signals. It is suggested that a regional multi-regression analysis with a band-limited spectral gravity signal as the observable, a method tested already 2 decades ago, can absorb possible significant disturbing signals, e.g. from topographic and crustal depth variations, and thereby recover the GIA signal.

  11. On the gravity and geoid effects of glacial isostatic adjustment in Fennoscandia - a short note

    NASA Astrophysics Data System (ADS)

    Sjöberg, L. E.

    2015-12-01

    Many geoscientists argue that there is a gravity low of 10-30 mGal in Fennoscandia as a remaining fingerprint of the last ice age and load, both vanished about 10 kyr ago. However, the extraction of the gravity signal related with Glacial Isostatic Adjustment (GIA) is complicated by the fact that the total gravity field is caused by many significant density distributions in the Earth. Here we recall a methodology originating with A. Bjerhammar 35 years ago, that emphasizes that the present land uplift phenomenon mainly occurs in the region thatwas covered by the ice cap, and it is highly correlated with the spectral window of degrees 10-22 of the global gravity field, whose lower limit fairly well corresponds to the wavelength that agrees with the size of the region. This implies that, although in principle the GIA is a global phenomenon, the geoid and gravity lows as well as the land upheaval in Fennoscandia are typically regional phenomena that cannot be seen in a global correlation study as it is blurred by many irrelevant gravity signals. It is suggested that a regional multi-regression analysis with a band-limited spectral gravity signal as the observable, a method tested already 2 decades ago, can absorb possible significant disturbing signals, e.g. from topographic and crustal depth variations, and thereby recover the GIA signal.

  12. Cascading effects of interparental conflict in adolescence: Linking threat appraisals, self-efficacy, and adjustment.

    PubMed

    Fosco, Gregory M; Feinberg, Mark E

    2015-02-01

    This study examined the longitudinal implications of adolescents' exposure to interparental conflict for their developmental success. In the proposed developmental cascade model, adolescents' perceptions of parental conflict as threatening is a risk factor for diminished self-efficacy, which would account for diminished adjustment. This study presents longitudinal data for 768 sixth-grade students and their families over four time points, ending in eighth grade. Analyses were conducted in three steps. First, replication of longitudinal support for threat as a mediator of the link between interparental conflict and emotional distress was found; however, findings did not support threat as a mediator of behavior problems or subjective well-being. Second, threat was found to mediate the longitudinal association between interparental conflict and self-efficacy. Third, a developmental cascade model supported a risk process in which interparental conflict was related to adolescents' threat appraisals, which undermined self-efficacy beliefs, and was then linked with emotional distress, behavior problems, and subjective well-being.

  13. Cascading Effects of Interparental Conflict in Adolescence: Linking Threat Appraisals, Self-Efficacy, and Adjustment

    PubMed Central

    Fosco, Gregory M.; Feinberg, Mark E.

    2015-01-01

    This study examined the longitudinal implications of adolescents’ exposure to interparental conflict for their developmental success. In the proposed developmental cascade model, adolescents’ perceptions of parental conflict as threatening is a risk factor for diminished self-efficacy, which would account for diminished adjustment. This study presents longitudinal data for 768 6th-grade students and their families over four time points, ending in 8th grade. Analyses were conducted in three steps. First, replication of longitudinal support for threat as a mediator of the link between interparental conflict and emotional distress was found; however, findings did not support threat as a mediator of behavior problems or subjective well-being. Second, threat was found to mediate the longitudinal association between interparental conflict and self-efficacy. Finally, a developmental cascade model supported a risk process in which interparental conflict was related to adolescents’ threat appraisals, which undermined self-efficacy beliefs, and was then linked with emotional distress, behavior problems, and subjective well-being. PMID:25017469

  14. Effects of the history of adoption in the emotional adjustment of adopted adolescents.

    PubMed

    Reppold, Caroline Tozzi; Hutz, Claudio Simon

    2009-11-01

    Since the decade of 1980, the model of stress and coping proposed for the assessment of vulnerability of adoptive families emphasizes that the emotional adjustment of those adopted is moderated by variables such as institutionalization, the manner and age at which the adoption was revealed, the change of first name, and the contact with the biological family. The objective of this study was to investigate the relationship of these variables to the perceived parenting style, mood, and self-esteem of the adopted adolescents. Participants in the study were 68 adolescents, between the ages of 14 and 15, adopted during infancy through judicial channels. The adolescents responded to a questionnaire about the history of adoption and to scales of Parenting Styles, Depression and Self-esteem. The main results indicated that the late revelation of adoption and the change of the first name are connected to higher levels of depression and low self-esteem and to more frequent perceptions of negligent or authoritarian parenting style. The contact with the biological family was frequently mentioned among those who perceived their parents as authoritative and presented the best indicator of mood and self-esteem. These findings were discussed in light of the necessity for multidisciplinary actions which can improve the psychological adaptation of the adopting families.

  15. Cascading effects of interparental conflict in adolescence: Linking threat appraisals, self-efficacy, and adjustment.

    PubMed

    Fosco, Gregory M; Feinberg, Mark E

    2015-02-01

    This study examined the longitudinal implications of adolescents' exposure to interparental conflict for their developmental success. In the proposed developmental cascade model, adolescents' perceptions of parental conflict as threatening is a risk factor for diminished self-efficacy, which would account for diminished adjustment. This study presents longitudinal data for 768 sixth-grade students and their families over four time points, ending in eighth grade. Analyses were conducted in three steps. First, replication of longitudinal support for threat as a mediator of the link between interparental conflict and emotional distress was found; however, findings did not support threat as a mediator of behavior problems or subjective well-being. Second, threat was found to mediate the longitudinal association between interparental conflict and self-efficacy. Third, a developmental cascade model supported a risk process in which interparental conflict was related to adolescents' threat appraisals, which undermined self-efficacy beliefs, and was then linked with emotional distress, behavior problems, and subjective well-being. PMID:25017469

  16. Estimating peer effects in networks with peer encouragement designs

    PubMed Central

    Eckles, Dean; Kizilcec, René F.; Bakshy, Eytan

    2016-01-01

    Peer effects, in which the behavior of an individual is affected by the behavior of their peers, are central to social science. Because peer effects are often confounded with homophily and common external causes, recent work has used randomized experiments to estimate effects of specific peer behaviors. These experiments have often relied on the experimenter being able to randomly modulate mechanisms by which peer behavior is transmitted to a focal individual. We describe experimental designs that instead randomly assign individuals’ peers to encouragements to behaviors that directly affect those individuals. We illustrate this method with a large peer encouragement design on Facebook for estimating the effects of receiving feedback from peers on posts shared by focal individuals. We find evidence for substantial effects of receiving marginal feedback on multiple behaviors, including giving feedback to others and continued posting. These findings provide experimental evidence for the role of behaviors directed at specific individuals in the adoption and continued use of communication technologies. In comparison, observational estimates differ substantially, both underestimating and overestimating effects, suggesting that researchers and policy makers should be cautious in relying on them. PMID:27382145

  17. Estimating Hydraulic Parameters When Poroelastic Effects Are Significant

    USGS Publications Warehouse

    Berg, S.J.; Hsieh, P.A.; Illman, W.A.

    2011-01-01

    For almost 80 years, deformation-induced head changes caused by poroelastic effects have been observed during pumping tests in multilayered aquifer-aquitard systems. As water in the aquifer is released from compressive storage during pumping, the aquifer is deformed both in the horizontal and vertical directions. This deformation in the pumped aquifer causes deformation in the adjacent layers, resulting in changes in pore pressure that may produce drawdown curves that differ significantly from those predicted by traditional groundwater theory. Although these deformation-induced head changes have been analyzed in several studies by poroelasticity theory, there are at present no practical guidelines for the interpretation of pumping test data influenced by these effects. To investigate the impact that poroelastic effects during pumping tests have on the estimation of hydraulic parameters, we generate synthetic data for three different aquifer-aquitard settings using a poroelasticity model, and then analyze the synthetic data using type curves and parameter estimation techniques, both of which are based on traditional groundwater theory and do not account for poroelastic effects. Results show that even when poroelastic effects result in significant deformation-induced head changes, it is possible to obtain reasonable estimates of hydraulic parameters using methods based on traditional groundwater theory, as long as pumping is sufficiently long so that deformation-induced effects have largely dissipated. ?? 2011 The Author(s). Journal compilation ?? 2011 National Ground Water Association.

  18. Estimating peer effects in networks with peer encouragement designs.

    PubMed

    Eckles, Dean; Kizilcec, René F; Bakshy, Eytan

    2016-07-01

    Peer effects, in which the behavior of an individual is affected by the behavior of their peers, are central to social science. Because peer effects are often confounded with homophily and common external causes, recent work has used randomized experiments to estimate effects of specific peer behaviors. These experiments have often relied on the experimenter being able to randomly modulate mechanisms by which peer behavior is transmitted to a focal individual. We describe experimental designs that instead randomly assign individuals' peers to encouragements to behaviors that directly affect those individuals. We illustrate this method with a large peer encouragement design on Facebook for estimating the effects of receiving feedback from peers on posts shared by focal individuals. We find evidence for substantial effects of receiving marginal feedback on multiple behaviors, including giving feedback to others and continued posting. These findings provide experimental evidence for the role of behaviors directed at specific individuals in the adoption and continued use of communication technologies. In comparison, observational estimates differ substantially, both underestimating and overestimating effects, suggesting that researchers and policy makers should be cautious in relying on them. PMID:27382145

  19. How to perform meaningful estimates of genetic effects.

    PubMed

    Alvarez-Castro, José M; Le Rouzic, Arnaud; Carlborg, Orjan

    2008-05-01

    Although the genotype-phenotype map plays a central role both in Quantitative and Evolutionary Genetics, the formalization of a completely general and satisfactory model of genetic effects, particularly accounting for epistasis, remains a theoretical challenge. Here, we use a two-locus genetic system in simulated populations with epistasis to show the convenience of using a recently developed model, NOIA, to perform estimates of genetic effects and the decomposition of the genetic variance that are orthogonal even under deviations from the Hardy-Weinberg proportions. We develop the theory for how to use this model in interval mapping of quantitative trait loci using Halley-Knott regressions, and we analyze a real data set to illustrate the advantage of using this approach in practice. In this example, we show that departures from the Hardy-Weinberg proportions that are expected by sampling alone substantially alter the orthogonal estimates of genetic effects when other statistical models, like F2 or G2A, are used instead of NOIA. Finally, for the first time from real data, we provide estimates of functional genetic effects as sets of effects of natural allele substitutions in a particular genotype, which enriches the debate on the interpretation of genetic effects as implemented both in functional and in statistical models. We also discuss further implementations leading to a completely general genotype-phenotype map. PMID:18451979

  20. Effects of adjusting cropping systems on utilization efficiency of climatic resources in Northeast China under future climate scenarios

    NASA Astrophysics Data System (ADS)

    Guo, Jianping; Zhao, Junfang; Xu, Yanhong; Chu, Zheng; Mu, Jia; Zhao, Qian

    Quantitatively evaluating the effects of adjusting cropping systems on the utilization efficiency of climatic resources under climate change is an important task for assessing food security in China. To understand these effects, we used daily climate variables obtained from the regional climate model RegCM3 from 1981 to 2100 under the A1B scenario and crop observations from 53 agro-meteorological experimental stations from 1981 to 2010 in Northeast China. Three one-grade zones of cropping systems were divided by heat, water, topography and crop-type, including the semi-arid areas of the northeast and northwest (III), the one crop area of warm-cool plants in semi-humid plain or hilly regions of the northeast (IV), and the two crop area in irrigated farmland in the Huanghuaihai Plain (VI). An agro-ecological zone model was used to calculate climatic potential productivities. The effects of adjusting cropping systems on climate resource utilization in Northeast China under the A1B scenario were assessed. The results indicated that from 1981 to 2100 in the III, IV and VI areas, the planting boundaries of different cropping systems in Northeast China obviously shifted toward the north and the east based on comprehensively considering the heat and precipitation resources. However, due to high temperature stress, the climatic potential productivity of spring maize was reduced in the future. Therefore, adjusting the cropping system is an effective way to improve the climatic potential productivity and climate resource utilization. Replacing the one crop in one year model (spring maize) by the two crops in one year model (winter wheat and summer maize) significantly increased the total climatic potential productivity and average utilization efficiencies. During the periods of 2011-2040, 2041-2070 and 2071-2100, the average total climatic potential productivities of winter wheat and summer maize increased by 9.36%, 11.88% and 12.13% compared to that of spring maize

  1. Questionnaire assessment of estimated radiation effects upon military task performance

    SciTech Connect

    Glickman, A.S.; Winne, P.S.; Morgan, B.B. Jr.; Moe, R.B.

    1984-04-01

    One hundred twenty-five supervisors in four types of U.S. Army combat systems estimated the degree of degradation of military tasks for 30 descriptive symptom complexes associated with various radiation exposures. Results indicated that (a) the relative order of symptom effects were highly consistent across positions and the types of systems, (b) performances were expected to be deleteriously affected under most illness conditions, even mild ones, but incapacitation was not anticipated until illness conditions became quite severe, and (c) the most important factors in estimating performances were fluid loss and fatigability/weakness.

  2. Estimating two-loop radiative effects in the MOLLER experiment

    SciTech Connect

    Aleksejevs, A. G.; Barkanova, S. G.; Zykunov, V. A.; Kuraev, E. A.

    2013-07-15

    Within the on-shell renormalization scheme, two-loop electroweak corrections to the parityviolating polarization asymmetry in the reaction e{sup -}e{sup -} {yields} e{sup -}e{sup -}({gamma}, {gamma}{gamma}) were estimated for the MOLLER experiment at JLab. The infrared divergence and the imaginary part of the amplitude were taken completely under control. Relevant compact expressions obtained by using asymptotic methods are free from unphysical parameters and are convenient for analysis and for numerical estimations. A numerical analysis revealed a significant scale of two-loop effects and the need for taking them into account in the MOLLER experiment.

  3. Causal effects of alcoholism on earnings: estimates from the NLSY.

    PubMed

    Jones, Alison Snow; Richmond, David W

    2006-08-01

    Propensity score matching is used to investigate the causal relationship between alcoholism and earnings in a young cohort of males and females drawn from the 1989 and 1994 National Longitudinal Survey of Youth (NLSY) in order to investigate productivity losses attributed to alcoholism and to quantify these effects. Results suggest that there are productivity losses attributable to alcoholism; that they become more pronounced over the life cycle; and that they differ between men and women. Ways in which estimates from propensity score matching may or may not improve on instrumental variables estimates are discussed.

  4. Adjusted peak-flow frequency estimates for selected streamflow-gaging stations in or near Montana based on data through water year 2011: Chapter D in Montana StreamStats

    USGS Publications Warehouse

    Sando, Steven K.; Sando, Roy; McCarthy, Peter M.; Dutton, DeAnn M.

    2016-04-05

    The climatic conditions of the specific time period during which peak-flow data were collected at a given streamflow-gaging station (hereinafter referred to as gaging station) can substantially affect how well the peak-flow frequency (hereinafter referred to as frequency) results represent long-term hydrologic conditions. Differences in the timing of the periods of record can result in substantial inconsistencies in frequency estimates for hydrologically similar gaging stations. Potential for inconsistency increases with decreasing peak-flow record length. The representativeness of the frequency estimates for a short-term gaging station can be adjusted by various methods including weighting the at-site results in association with frequency estimates from regional regression equations (RREs) by using the Weighted Independent Estimates (WIE) program. Also, for gaging stations that cannot be adjusted by using the WIE program because of regulation or drainage areas too large for application of RREs, frequency estimates might be improved by using record extension procedures, including a mixed-station analysis using the maintenance of variance type I (MOVE.1) procedure. The U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources and Conservation, completed a study to provide adjusted frequency estimates for selected gaging stations through water year 2011.The purpose of Chapter D of this Scientific Investigations Report is to present adjusted frequency estimates for 504 selected streamflow-gaging stations in or near Montana based on data through water year 2011. Estimates of peak-flow magnitudes for the 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities are reported. These annual exceedance probabilities correspond to the 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively.The at-site frequency estimates were

  5. The Estimated Effects of Service Learning on Students' Intercultural Effectiveness

    ERIC Educational Resources Information Center

    Kilgo, Cindy A.

    2015-01-01

    As the higher education landscape continues to diversify, intercultural effectiveness comes to the forefront among important outcomes for students. Service learning is one programmatic tool that institutions of higher education can use to foster the development of intercultural effectiveness. This study provides evidence that service learning is…

  6. Estimation of the Dose and Dose Rate Effectiveness Factor

    NASA Technical Reports Server (NTRS)

    Chappell, L.; Cucinotta, F. A.

    2013-01-01

    Current models to estimate radiation risk use the Life Span Study (LSS) cohort that received high doses and high dose rates of radiation. Transferring risks from these high dose rates to the low doses and dose rates received by astronauts in space is a source of uncertainty in our risk calculations. The solid cancer models recommended by BEIR VII [1], UNSCEAR [2], and Preston et al [3] is fitted adequately by a linear dose response model, which implies that low doses and dose rates would be estimated the same as high doses and dose rates. However animal and cell experiments imply there should be curvature in the dose response curve for tumor induction. Furthermore animal experiments that directly compare acute to chronic exposures show lower increases in tumor induction than acute exposures. A dose and dose rate effectiveness factor (DDREF) has been estimated and applied to transfer risks from the high doses and dose rates of the LSS cohort to low doses and dose rates such as from missions in space. The BEIR VII committee [1] combined DDREF estimates using the LSS cohort and animal experiments using Bayesian methods for their recommendation for a DDREF value of 1.5 with uncertainty. We reexamined the animal data considered by BEIR VII and included more animal data and human chromosome aberration data to improve the estimate for DDREF. Several experiments chosen by BEIR VII were deemed inappropriate for application to human risk models of solid cancer risk. Animal tumor experiments performed by Ullrich et al [4], Alpen et al [5], and Grahn et al [6] were analyzed to estimate the DDREF. Human chromosome aberration experiments performed on a sample of astronauts within NASA were also available to estimate the DDREF. The LSS cohort results reported by BEIR VII were combined with the new radiobiology results using Bayesian methods.

  7. Effects of Ocean Tide Models on Gnss-Estimated Ztd and Pwv in Turkey

    NASA Astrophysics Data System (ADS)

    Gurbuz, G.; Jin, S.; Mekik, C.

    2015-12-01

    Global Navigation Satellite System (GNSS) observations can precisely estimate the total zenith tropospheric delay (ZTD) and precipitable water vapour (PWV) for weather prediction and atmospheric research as a continuous and all-weather technique. However, apart from GNSS technique itself, estimations of ZTD and PWV are subject to effects of geophysical models with large uncertainties, particularly imprecise ocean tide models in Turkey. In this paper, GNSS data from Jan. 1st to Dec. 31st of 2014 are processed at 4 co-located GNSS stations (GISM, DIYB, GANM, and ADAN) with radiosonde from Turkish Met-Office along with several nearby IGS stations. The GAMIT/GLOBK software has been used to process GNSS data of 30-second sample using the Vienna Mapping Function and 10° elevation cut-off angle. Also tidal and non-tidal atmospheric pressure loadings (ATML) at the observation level are also applied in GAMIT/GLOBK. Several widely used ocean tide models are used to evaluate their effects on GNSS-estimated ZTD and PWV estimation, such as IERS recommended FES2004, NAO99b from a barotropic hydrodynamic model, CSR4.0 obtained from TOPEX/Poseidon altimetry with the model FES94.1 as the reference model and GOT00 which is again long wavelength adjustments of FES94.1 using TOPEX/Poseidon data at 0.5 by 0.5 degree grid. The ZTD and PWV computed from radiosonde profile observations are regarded as reference values for the comparison and validation. In the processing phase, five different strategies are taken without ocean tide model and with four aforementioned ocean tide models, respectively, which are used to evaluate ocean tide models effects on GNSS-estimated ZTD and PWV estimation through comparing with co-located Radiosonde. Results showed that ocean tide models have greatly affected the estimation of the ZTD in centimeter level and thus the precipitable water vapour in millimeter level, respectively at stations near coasts. The ocean tide model FES2004 that is the product of

  8. Estimates of the rate and distribution of fitness effects of spontaneous mutation in Saccharomyces cerevisiae.

    PubMed Central

    Zeyl, C; DeVisser, J A

    2001-01-01

    The per-genome, per-generation rate of spontaneous mutation affecting fitness (U) and the mean fitness cost per mutation (s) are important parameters in evolutionary genetics, but have been estimated for few species. We estimated U and sh (the heterozygous effect of mutations) for two diploid yeast strains differing only in the DNA mismatch-repair deficiency used to elevate the mutation rate in one (mutator) strain. Mutations were allowed to accumulate in 50 replicate lines of each strain, during 36 transfers of randomly chosen single colonies (approximately 600 generations). Among wild-type lines, fitnesses were bimodal, with one mode showing no change in mean fitness. The other mode showed a mean 29.6% fitness decline and the petite phenotype, usually caused by partial deletion of the mitochondrial genome. Excluding petites, maximum-likelihood estimates adjusted for the effect of selection were U = 9.5 x 10(-5) and sh = 0.217 for the wild type. Among the mutator lines, the best fit was obtained with 0.005 < or = U < or = 0.94 and 0.049 > or = sh > or = 0.0003. Like other recently tested model organisms, wild-type yeast have low mutation rates, with high mean fitness costs per mutation. Inactivation of mismatch repair increases the frequency of slightly deleterious mutations by approximately two orders of magnitude. PMID:11139491

  9. Monte Carlo Investigation on the Effect of Heterogeneities on Strut Adjusted Volume Implant (SAVI) Dosimetry

    NASA Astrophysics Data System (ADS)

    Koontz, Craig

    Breast cancer is the most prevalent cancer for women with more than 225,000 new cases diagnosed in the United States in 2012 (ACS, 2012). With the high prevalence, comes an increased emphasis on researching new techniques to treat this disease. Accelerated partial breast irradiation (APBI) has been used as an alternative to whole breast irradiation (WBI) in order to treat occult disease after lumpectomy. Similar recurrence rates have been found using ABPI after lumpectomy as with mastectomy alone, but with the added benefit of improved cosmetic and psychological results. Intracavitary brachytherapy devices have been used to deliver the APBI prescription. However, inability to produce asymmetric dose distributions in order to avoid overdosing skin and chest wall has been an issue with these devices. Multi-lumen devices were introduced to overcome this problem. Of these, the Strut-Adjusted Volume Implant (SAVI) has demonstrated the greatest ability to produce an asymmetric dose distribution, which would have greater ability to avoid skin and chest wall dose, and thus allow more women to receive this type of treatment. However, SAVI treatments come with inherent heterogeneities including variable backscatter due to the proximity to the tissue-air and tissue-lung interfaces and variable contents within the cavity created by the SAVI. The dose calculation protocol based on TG-43 does not account for heterogeneities and thus will not produce accurate dosimetry; however Acuros, a model-based dose calculation algorithm manufactured by Varian Medical Systems, claims to accurately account for heterogeneities. Monte Carlo simulation can calculate the dosimetry with high accuracy. In this thesis, a model of the SAVI will be created for Monte Carlo, specifically using MCNP code, in order to explore the affects of heterogeneities on the dose distribution. This data will be compared to TG-43 and Acuros calculated dosimetry to explore their accuracy.

  10. Labor Market Effects of Human Capital and of Its Adjustment to Technological Change.

    ERIC Educational Resources Information Center

    Mincer, Jacob

    This document, a review of labor market effects of human capital, focuses on two related topics. Part I describes the following early findings of the research on effects of education and job training on the wage structure, labor turnover, and unemployment: decline of training with experience, positive and significant effects of training on length…

  11. Life satisfaction and adjustment of children of alcoholics: the effects of parental drinking, family disorganization and survival roles.

    PubMed

    Braithwaite, V; Devine, C

    1993-11-01

    The stress paradigm was used to investigate the extent to which parental alcohol dependency, family disorganization ana Black's (1979) and Wegscheider's (1976) survival roles affected the adjustment of children of alcoholics (COAs). The study was cross-sectional based on the responses of a non-random community sample of 112 adolescents. The predictors of life satisfaction differed from the predictors of minor psychiatric symptoms. Parental alcohol dependency had no direct effect on minor psychiatric symptoms, with low family cohesiveness and intimacy being the major determinants of psychopathology. In contrast, parental alcohol dependency and family disharmony had an additive effect on level of life satisfaction. Family variables did not buffer children from the effects of alcohol once they recognized parental drinking as a problem. Nor did the survival roles protect children in any way. Indeed, the roles of the 'lost' child, the 'acting-out' child, and the 'clown' were detrimental to well-being.

  12. Making sense of genetic estimates of effective population size.

    PubMed

    Waples, Robin S

    2016-10-01

    The last decade has seen an explosion of interest in use of genetic markers to estimate effective population size, Ne . Effective population size is important both theoretically (Ne is a key parameter in almost every aspect of evolutionary biology) and for practical application (Ne determines rates of genetic drift and loss of genetic variability and modulates the effectiveness of selection, so it is crucial to consider in conservation). As documented by Palstra & Fraser (), most of the recent growth in Ne estimation can be attributed to development or refinement of methods that can use a single sample of individuals (the older temporal method requires at least two samples separated in time). As with other population genetic methods, performance of new Ne estimators is typically evaluated with simulated data for a few scenarios selected by the author(s). Inevitably, these initial evaluations fail to fully consider the consequences of violating simplifying assumptions, such as discrete generations, closed populations of constant size and selective neutrality. Subsequently, many researchers studying natural or captive populations have reported estimates of Ne for multiple methods; often these estimates are congruent, but that is not always the case. Because true Ne is rarely known in these empirical studies, it is difficult to make sense of the results when estimates differ substantially among methods. What is needed is a rigorous, comparative analysis under realistic scenarios for which true Ne is known. Recently, Gilbert & Whitlock () did just that for both single-sample and temporal methods under a wide range of migration schemes. In the current issue of Molecular Ecology, Wang () uses simulations to evaluate performance of four single-sample Ne estimators. In addition to assessing effects of true Ne , sample size, and number of loci, Wang also evaluated performance under changing abundance, physical linkage and genotyping errors, as well as for some alternative

  13. Effect of distance-related heterogeneity on population size estimates from point counts

    USGS Publications Warehouse

    Efford, Murray G.; Dawson, Deanna K.

    2009-01-01

    Point counts are used widely to index bird populations. Variation in the proportion of birds counted is a known source of error, and for robust inference it has been advocated that counts be converted to estimates of absolute population size. We used simulation to assess nine methods for the conduct and analysis of point counts when the data included distance-related heterogeneity of individual detection probability. Distance from the observer is a ubiquitous source of heterogeneity, because nearby birds are more easily detected than distant ones. Several recent methods (dependent double-observer, time of first detection, time of detection, independent multiple-observer, and repeated counts) do not account for distance-related heterogeneity, at least in their simpler forms. We assessed bias in estimates of population size by simulating counts with fixed radius w over four time intervals (occasions). Detection probability per occasion was modeled as a half-normal function of distance with scale parameter sigma and intercept g(0) = 1.0. Bias varied with sigma/w; values of sigma inferred from published studies were often 50% for a 100-m fixed-radius count. More critically, the bias of adjusted counts sometimes varied more than that of unadjusted counts, and inference from adjusted counts would be less robust. The problem was not solved by using mixture models or including distance as a covariate. Conventional distance sampling performed well in simulations, but its assumptions are difficult to meet in the field. We conclude that no existing method allows effective estimation of population size from point counts.

  14. The Cost-Effectiveness of Laparoscopic Adjustable Gastric Banding in the Morbidly Obese Adult Population of Australia

    PubMed Central

    Lee, Yong Yi; Veerman, J. Lennert; Barendregt, Jan J.

    2013-01-01

    Background To examine the cost-effectiveness of providing laparoscopic adjustable gastric banding (LAGB) surgery to all morbidly obese adults in the 2003 Australian population. Methods and Findings Analyzed costs and benefits associated with two intervention scenarios, one providing LAGB surgery to individuals with BMI >40 and another to individuals with BMI >35, with each compared relative to a ‘do nothing’ scenario. A multi-state, multiple cohort Markov model was used to determine the cost-effectiveness of LAGB surgery over the lifetime of each cohort. All costs and health outcomes were assessed from an Australian health sector perspective and were discounted using a 3% annual rate. Uncertainty and sensitivity analyzes were conducted to test the robustness of model outcomes. Incremental cost-effectiveness ratios (ICERs) were measured in 2003 Australian dollars per disability adjusted life year (DALY) averted. The ICER for the scenario providing LAGB surgery to all individuals with a BMI >40 was dominant [95% CI: dominant - $588] meaning that the intervention led to both improved health and cost savings. The ICER when providing surgery to those with a BMI >35 was $2 154/DALY averted [95% CI: dominant - $6 033]. Results were highly sensitive to changes in the likelihood of long-term complications. Conclusion LAGB surgery is highly cost-effective when compared to the $50 000/DALY threshold for cost-effectiveness used in Australia. LAGB surgery also ranks highly in terms of cost-effectiveness when compared to other population-level interventions for weight loss in Australia. The results of this study are in line with other economic evaluations on LAGB surgery. This study recommends that the Australian federal government provide a full subsidy for LAGB surgery to morbidly obese Australians with a BMI >40. PMID:23717680

  15. Examining the Effects of Residence and Gender on College Student Adjustment in Iran: Implications for Psychotherapists

    ERIC Educational Resources Information Center

    Mohammadi, Mehdi; Schwitzer, Alan M.; Nunnery, John

    2010-01-01

    This study examined the effects of on-campus residence, in comparison with commuter status, on academic performance, vocational commitment, self-efficacy, and perceptions of the college environment among female and male Iranian students at Shiraz University, Iran. The study sought to extend previous work investigating the effects of college…

  16. 20 CFR 418.1230 - What is the effective date of an income-related monthly adjustment amount initial determination...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-related monthly adjustment amount initial determination that is based on a more recent tax year? 418.1230... Income-Related Monthly Adjustment Amount Determinations Using A More Recent Tax Year's Modified Adjusted... initial determination that is based on a more recent tax year? (a) When you make your request prior...

  17. 20 CFR 418.1230 - What is the effective date of an income-related monthly adjustment amount initial determination...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...-related monthly adjustment amount initial determination that is based on a more recent tax year? 418.1230... Income-Related Monthly Adjustment Amount Determinations Using A More Recent Tax Year's Modified Adjusted... initial determination that is based on a more recent tax year? (a) When you make your request prior...

  18. 20 CFR 418.2230 - What is the effective date of an income-related monthly adjustment amount initial determination...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...-related monthly adjustment amount initial determination based on a more recent tax year? 418.2230 Section... Adjustments to Medicare Prescription Drug Coverage Premiums Determinations Using A More Recent Tax Year's... adjustment amount initial determination based on a more recent tax year? We will follow the rules in §...

  19. Correcting overestimated effect size estimates in multiple trials.

    PubMed

    Wiedermann, Wolfgang; Gula, Bartosz; Czech, Paul; Muschik, Denise

    2011-01-01

    In a simulation study, Brand, Bradley, Best, and Stoica (2011) have shown that Cohen's d is notably overestimated if computed for data aggregated over multiple trials. Although the phenomenon is highly important for studies and meta-analyses of studies structurally similar to the simulated scenario, the authors do not comprehensively address how the problem could be handled. In this comment, we first suggest a corrective term d(')c that includes the number and correlation of trials. Next, the results of a simulation study provide evidence that the proposed dc' results in a more precise estimation of trial-level effects. We conclude that, in practice, d( ')c together with plausible estimates of inter-trial correlation will produce a more precise effect size range compared to that suggested by Brand and colleagues (2011).

  20. Relationship between efficiency and clinical effectiveness indicators in an adjusted model of resource consumption: a cross-sectional study

    PubMed Central

    2013-01-01

    Background Adjusted clinical groups (ACG®) have been widely used to adjust resource distribution; however, the relationship with effectiveness has been questioned. The purpose of the study was to measure the relationship between efficiency assessed by ACG® and a clinical effectiveness indicator in adults attended in Primary Health Care Centres (PHCs). Methods Research design: cross-sectional study. Subjects: 196, 593 patients aged >14 years in 13 PHCs in Catalonia (Spain). Measures: Age, sex, PHC, basic care team (BCT), visits, episodes (diagnoses), and total direct costs of PHC care and co-morbidity as measured by ACG® indicators: Efficiency indices for costs, visits, and episodes (costs EI, visits EI, episodes EI); a complexity or risk index (RI); and effectiveness measured by a general synthetic index (SI). The relationship between EI, RI, and SI in each PHC and BCT was measured by multiple correlation coefficients (r). Results In total, 56 of the 106 defined ACG® were present in the study population, with five corresponding to 44.5% of the patients, 11 to 68.0% of patients, and 30 present in less than 0.5% of the sample. The RI in each PHC ranged from 0.9 to 1.1. Costs, visits, and episodes had similar trends for efficiency in six PHCs. There was moderate correlation between costs EI and visits EI (r = 0.59). SI correlation with episodes EI and costs EI was moderate (r = 0.48 and r = −0.34, respectively) and was r = −0.14 for visits EI. Correlation between RI and SI was r = 0.29. Conclusions The Efficiency and Effectiveness ACG® indicators permit a comparison of primary care processes between PHCs. Acceptable correlation exists between effectiveness and indicators of efficiency in episodes and costs. PMID:24139144

  1. Simultaneous Detection And Estimation Amid Strong Dynamical Effects

    NASA Technical Reports Server (NTRS)

    Kumar, Rajendra

    1991-01-01

    Effective signal-to-noise ratio several decibels greater than in previous schemes. Proposed for digital processing of received noisy, binary-phase-modulated radio signal for simultaneous detection of binary modulation and estimation of Doppler phase, frequency, and frequency derivative. Intended for use where relative motion between transmitter and receiver includes large velocities, strong accelerations, and/or intense jerks, resulting in possibly large Doppler frequency shifts with respect to time. Improves reception in radar, mobile/satellite communications, and navigation systems.

  2. Comparison of validity of food group intake by food frequency questionnaire between pre- and post- adjustment estimates derived from 2-day 24-hour recalls in combination with the probability of consumption.

    PubMed

    Kim, Dong Woo; Oh, Se-Young; Kwon, Sung-Ok; Kim, Jeongseon

    2012-01-01

    Validation of a food frequency questionnaire (FFQ) utilising a short-term measurement method is challenging when the reference method does not accurately reflect the usual food intake. In addition, food group intake that is not consumed on daily basis is more critical when episodically consumed foods are related and compared. To overcome these challenges, several statistical approaches have been developed to determine usual food intake distributions. The Multiple Source Method (MSM) can calculate the usual food intake by combining the frequency questions of an FFQ with the short-term food intake amount data. In this study, we applied the MSM to estimate the usual food group intake and evaluate the validity of an FFQ with a group of 333 Korean children (aged 3-6 y) who completed two 24-hour recalls (24HR) and one FFQ in 2010. After adjusting the data using the MSM procedure, the true rate of non-consumption for all food groups was less than 1% except for the beans group. The median Spearman correlation coefficients against FFQ of the mean of 2-d 24HRs data and the MSM-adjusted data were 0.20 (range: 0.11 to 0.40) and 0.35 (range: 0.14 to 0.60), respectively. The weighted kappa values against FFQ ranged from 0.08 to 0.25 for the mean of 2-d 24HRs data and from 0.10 to 0.41 for the MSM-adjusted data. For most food groups, the MSM-adjusted data showed relatively stronger correlations against FFQ than raw 2-d 24HRs data, from 0.03 (beverages) to 0.34 (mushrooms). The results of this study indicated that the application of the MSM, which was a better estimate of the usual intake, could be worth considering in FFQ validation studies among Korean children.

  3. Estimating terra MODIS polarization effect using ocean data

    NASA Astrophysics Data System (ADS)

    Wald, Andrew; Brinkmann, Jake; Wu, Aisheng; Xiong, Jack

    2016-05-01

    Terra MODIS has been known since pre-launch to have polarization sensitivity, particularly in shortest-wavelength bands 8 and 9. On-orbit reflectance trending of pseudo-invariant sites show a variation in reflectance as a function of band and scan mirror angle of incidence consistent with time-dependent polarization effects from the rotating doublesided scan mirror. The MODIS Characterization Support Team [MCST] estimates the Mueller matrix trending from this variation as observed from a single desert site, but this effect is not included in Collection 6 [C6] calibration. Here we extend the MCST's current polarization sensitivity monitoring to two ocean sites distributed over latitude to help estimate the uncertainties in the derived Mueller matrix. The Mueller matrix elements derived for polarization-sensitive Band 8 for a given site are found to be fairly insensitive to surface brdf modeling. The site-to-site variation is a measure of the uncertainty in the Mueller estimation. Results for band 8 show that the polarization correction reduces mirror-side striping by up to 50% and reduces the instrument polarization effect on reflectance time series of an ocean target.

  4. The effects of growth hormone deficiency and growth hormone replacement therapy on intellectual ability, personality and adjustment in children.

    PubMed

    Puga González, B; Ferrández Longás, A; Oyarzábal, M; Nosas, R

    2010-06-01

    Traditionally, it has been assumed that intellectual development in children with growth hormone deficiency (GHD) is distributed between ranges of a normal population based on the observation that it does not differ substantially from that of children of the same age. Nevertheless, few studies have investigated this assumption. This Spanish Collaborative study was prospectively planned with two main purposes: to study a possible influence of GHD on intelligence quotient (IQ), personality traits and adaptative capacity and to study the evolution of these parameters during substitution therapy with growth hormone (GH). Although the overall intellectual ability of children with GHD is comparable to that of a normal reference population, some areas such the motor-component scale (evaluated by McCarthy test) and performance IQ (evaluated by WISC-R) were below the mean at the beginning of the study, showing significant improvement during therapy. Emotional adjustment (normal at study start) also improved significantly during treatment. Females showed better adjustment capacity before and during GH therapy. Longer studies with an increased number of cases are needed to confirm these effects of GHD and its treatment in children.

  5. The Effects of Sensorimotor Training on Anticipatory Postural Adjustment of the Trunk in Chronic Low Back Pain Patients

    PubMed Central

    Hwang, Jin Ah; Bae, Sea Hyun; Do Kim, Gi; Kim, Kyung Yoon

    2013-01-01

    [Purpose] This study aimed to examine the effects of sensorimotor training on the anticipatory postural adjustment (APA) of chronic low back pain (CLBP) patients. [Subjects and Methods] Fourteen CLBP patients were randomly assigned to Group II (ordinary physical therapy, n=7) and Group III (sensorimotor training, n=7). In addition, a normal group (Group I) consisting of seven subjects was chosen as the control group. The two CLBP groups received their own treatment five times per week, for four weeks, for 40 minutes each time. Changes in pain and functional performance evaluation were examined by the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). In order to look at the change in APA, muscle onset time was examined using electromyography (EMG). [Results] Group III showed significant changes in both VAS and ODI. According to comparison of the results for muscle onset time, there were significant decreases in Group III's transversus abdominis muscle (TrA) and external oblique muscle (EO) in the standing and sitting positions. There were significant differences between Group II and III in terms of the TrA in the sitting position. [Conclusion] Sensorimotor training makes patients capable of learning how to adjust muscles, thereby alleviating pain and improving muscle performance. PMID:24259943

  6. [Effects of exogenous melatonin on nitrogen metabolism and osmotic adjustment substances of melon seedlings under sub-low temperature].

    PubMed

    Gao, Qing-hai; Jia, Shuang-shuang; Miao, Yong-mei; Lu, Xiao-min; Li, Hui-min

    2016-02-01

    The melon cultivar 'Yangjiaosu' was subjected to the treatment of 18 °C/12 °C (day/night) in an artificial climate chamber for 6 days, and the activities of nitrogen metabolism related enzymes [nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) ] , the contents of total N, NO3(-)-N and NH4+-N as well as the osmotic adjustment substances of melon leaf were then determined. The results showed that, compared with the control, sub-low temperature treatment reduced the contents of total N, NO3(-)-N and the NR activity, but increased the content of NH4(+)-N, thereby leading to the growth inhibition of melon. Exogenous MT treatment significantly improved the activities of nitrogen metabolism related enzymes, especially the activities of GS and GOGAT, effectively reducing the content of NH4+-N. Moreover, MT treatment increased the contents of proline, soluble protein and soluble sugar, and alleviated the damage of sub-low temperature on the cell membrane by reducing the relative electrical conductivity and MDA content of melon leaves. In short, this work suggested that exogenous MT would enhance the sub-low temperature adaptability of melon by decreasing the leaf content of NH4-N, increasing the contents of osmotic adjustment substances and reducing the membrane lipid peroxidation levels.

  7. [Effects of exogenous melatonin on nitrogen metabolism and osmotic adjustment substances of melon seedlings under sub-low temperature].

    PubMed

    Gao, Qing-hai; Jia, Shuang-shuang; Miao, Yong-mei; Lu, Xiao-min; Li, Hui-min

    2016-02-01

    The melon cultivar 'Yangjiaosu' was subjected to the treatment of 18 °C/12 °C (day/night) in an artificial climate chamber for 6 days, and the activities of nitrogen metabolism related enzymes [nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) ] , the contents of total N, NO3(-)-N and NH4+-N as well as the osmotic adjustment substances of melon leaf were then determined. The results showed that, compared with the control, sub-low temperature treatment reduced the contents of total N, NO3(-)-N and the NR activity, but increased the content of NH4(+)-N, thereby leading to the growth inhibition of melon. Exogenous MT treatment significantly improved the activities of nitrogen metabolism related enzymes, especially the activities of GS and GOGAT, effectively reducing the content of NH4+-N. Moreover, MT treatment increased the contents of proline, soluble protein and soluble sugar, and alleviated the damage of sub-low temperature on the cell membrane by reducing the relative electrical conductivity and MDA content of melon leaves. In short, this work suggested that exogenous MT would enhance the sub-low temperature adaptability of melon by decreasing the leaf content of NH4-N, increasing the contents of osmotic adjustment substances and reducing the membrane lipid peroxidation levels. PMID:27396126

  8. Estimation of Potential Population Level Effects of Contaminants on Wildlife

    SciTech Connect

    Loar, J.M.

    2001-06-11

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

  9. The Effects of Baseline Estimation on the Reliability, Validity, and Precision of CBM-R Growth Estimates

    ERIC Educational Resources Information Center

    Van Norman, Ethan R.; Christ, Theodore J.; Zopluoglu, Cengiz

    2013-01-01

    This study examined the effect of baseline estimation on the quality of trend estimates derived from Curriculum Based Measurement of Oral Reading (CBM-R) progress monitoring data. The authors used a linear mixed effects regression (LMER) model to simulate progress monitoring data for schedules ranging from 6-20 weeks for datasets with high and low…

  10. Adjustment of minimum seismic shear coefficient considering site effects for long-period structures

    NASA Astrophysics Data System (ADS)

    Guan, Minsheng; Du, Hongbiao; Cui, Jie; Zeng, Qingli; Jiang, Haibo

    2016-06-01

    Minimum seismic base shear is a key factor employed in the seismic design of long-period structures, which is specified in some of the major national seismic building codes viz. ASCE7-10, NZS1170.5 and GB50011-2010. In current Chinese seismic design code GB50011-2010, however, effects of soil types on the minimum seismic shear coefficient are not considered, which causes problems for long-period structures sited in hard or rock soil to meet the minimum base shear requirement. This paper aims to modify the current minimum seismic shear coefficient by taking into account site effects. For this purpose, effective peak acceleration (EPA) is used as a representation for the ordinate value of the design response spectrum at the plateau. A large amount of earthquake records, for which EPAs are calculated, are examined through the statistical analysis by considering soil conditions as well as the seismic fortification intensities. The study indicates that soil types have a significant effect on the spectral ordinates at the plateau as well as the minimum seismic shear coefficient. Modified factors related to the current minimum seismic shear coefficient are preliminarily suggested for each site class. It is shown that the modified seismic shear coefficients are more effective to the determination of minimum seismic base shear of long-period structures.

  11. A kinematic model to estimate effective dose of radioactive substances in a human body

    NASA Astrophysics Data System (ADS)

    Sasaki, S.; Yamada, T.

    2013-05-01

    The great earthquake occurred in the north-east area in Japan in March 11, 2011. Facility system to control Fukushima Daiichi nuclear power station was completely destroyed by the following giant tsunami. From the damaged reactor containment vessels, an amount of radioactive substances had leaked and diffused in the vicinity of this station. Radiological internal exposure became a serious social issue both in Japan and all over the world. The present study provides an easily understandable, kinematic-based model to estimate the effective dose of radioactive substances in a human body by simplifying the complicated mechanism of metabolism. International Commission on Radiological Protection (ICRP) has developed a sophisticated model, which is well-known as a standard method to calculate the effective dose for radiological protection. However, owing to that ICRP method is fine, it is rather difficult for non-professional people of radiology to gasp the whole images of the movement and the influences of radioactive substances in a human body. Therefore, in the present paper we propose a newly-derived and easily-understandable model to estimate the effective dose. The present method is very similar with the traditional and conventional tank model in hydrology. Ingestion flux of radioactive substances corresponds to rain intensity and the storage of radioactive substances to the water storage in a basin in runoff analysis. The key of the present method is to estimate the energy radiated in the radioactive nuclear disintegration of an atom by using classical theory of β decay and special relativity for various kinds of radioactive atoms. The parameters used in this model are only physical half-time and biological half-time, and there are no operational parameters or coefficients to adjust our theoretical runoff to ICRP. Figure shows the time-varying effective dose with ingestion duration, and we can confirm the validity of our model. The time-varying effective dose with

  12. A comparison of estimated and calculated effective porosity

    NASA Astrophysics Data System (ADS)

    Stephens, Daniel B.; Hsu, Kuo-Chin; Prieksat, Mark A.; Ankeny, Mark D.; Blandford, Neil; Roth, Tracy L.; Kelsey, James A.; Whitworth, Julia R.

    Effective porosity in solute-transport analyses is usually estimated rather than calculated from tracer tests in the field or laboratory. Calculated values of effective porosity in the laboratory on three different textured samples were compared to estimates derived from particle-size distributions and soil-water characteristic curves. The agreement was poor and it seems that no clear relationships exist between effective porosity calculated from laboratory tracer tests and effective porosity estimated from particle-size distributions and soil-water characteristic curves. A field tracer test in a sand-and-gravel aquifer produced a calculated effective porosity of approximately 0.17. By comparison, estimates of effective porosity from textural data, moisture retention, and published values were approximately 50-90% greater than the field calibrated value. Thus, estimation of effective porosity for chemical transport is highly dependent on the chosen transport model and is best obtained by laboratory or field tracer tests. Résumé La porosité effective dans les analyses de transport de soluté est habituellement estimée, plutôt que calculée à partir d'expériences de traçage sur le terrain ou au laboratoire. Les valeurs calculées de la porosité effective au laboratoire sur trois échantillons de textures différentes ont été comparées aux estimations provenant de distributions de taille de particules et de courbes caractéristiques sol-eau. La concordance était plutôt faible et il semble qu'il n'existe aucune relation claire entre la porosité effective calculée à partir des expériences de traçage au laboratoire et la porosité effective estimée à partir des distributions de taille de particules et de courbes caractéristiques sol-eau. Une expérience de traçage de terrain dans un aquifère de sables et de graviers a fourni une porosité effective calculée d'environ 0,17. En comparaison, les estimations de porosité effective de données de

  13. The Effects of Cross-Cultural Communication Education on International Students' Adjustment and Adaptation

    ERIC Educational Resources Information Center

    Young, Tony J.; Schartner, Alina

    2014-01-01

    The recent increase in the provision of cross- and intercultural education for sojourners has not been matched by commensurate research into its effects on participants. Evaluation, where undertaken at all, has been largely confined to expatriate business contexts and has tended to be undertaken pre-sojourn. Crucially, evaluation has not engaged…

  14. Impact of Father Involvement: A Closer Look at Indirect Effects Models Involving Marriage and Child Adjustment

    ERIC Educational Resources Information Center

    Goeke-Morey, Marcie C.; Cummings, E. Mark

    2007-01-01

    In this article we present a framework for understanding the indirect effects of fathering on child development in the context of the marriage. We discuss three central pathways of influence: through relations between marital quality and fathering, through children's exposure to father expressions of marital discord, and through relations between…

  15. Child adjustment and parent functioning: Considering the role of child-driven effects.

    PubMed

    Yan, Ni; Ansari, Arya

    2016-04-01

    Based on 13,694 mother-child dyads from the Early Childhood Longitudinal Kindergarten Study (ECLS-K; Rock & Pollack, 2002; Tourangeau, Nord, Lê, Sorongon, & Najarian, 2009), this study is an examination of the bidirectional relations between parental and child functioning from kindergarten through 3rd grade. Results from the cross-lagged models demonstrated that child-driven effects co-occurred with parental effects, and that these effects were comparable in size. At the same time, however, results from the latent profile analysis (LPA) revealed idiosyncratic patterns of parent and child functioning. Compared with children in the least optimal functioning profiles, those in the average and above-average profiles elicited greater improvement in parents' functioning over time. Although children characterized by poor academic performance at kindergarten appeared to precede parents characterized by harsh parenting at 3rd grade, there was a threshold in the evolving strength of the overall child-driven effects. Taken together, the results from this study underscore the importance of considering reciprocal processes in the parent-child dynamic while also underscoring individual differences in these processes across the early- to middle-childhood years.

  16. Longitudinal Effects of Teacher and Student Perceptions of Teacher-Student Relationship Qualities on Academic Adjustment

    ERIC Educational Resources Information Center

    Hughes, Jan N.

    2011-01-01

    The shared and unique effects of teacher and student reports of teacher-student relationship quality (TSRQ) in second and third grade on academic self-views, behavioral engagement, and achievement the following year were investigated in a sample of 714 academically at-risk students. Teacher and student reports of teacher-student support and…

  17. Romantic Relationships and Adjustment Problems in China: The Moderating Effect of Classroom Romantic Context

    ERIC Educational Resources Information Center

    Hou, Jinqin; Natsuaki, Misaki N.; Zhang, Jianxin; Guo, Fei; Huang, Zheng; Wang, Mianbo; Chen, Zhiyan

    2013-01-01

    Theoretical and empirical research has shown that adolescent romantic relationships are associated with a wide range of developmental outcomes, including adverse consequences. The present study used a hierarchical linear model to examine the moderating effect of classroom romantic context on the association between adolescent romantic…

  18. Effectiveness of Home Visiting as a Strategy for Promoting Children's Adjustment to School

    ERIC Educational Resources Information Center

    Kirkland, Kristen

    2013-01-01

    A growing body of evidence suggests that involving families in home visiting services promotes positive experiences during the initial years of a child's life; however less is known about whether or not the benefits continue to accrue after a child enters school. This article describes the results of a study examining the effectiveness of an…

  19. Indirect Estimation of the Comparative Treatment Effect in Pharmacogenomic Subgroups

    PubMed Central

    Sorich, Michael J.; Coory, Michael; Pekarsky, Brita A. K.

    2013-01-01

    Evidence of clinical utility is a key issue in translating pharmacogenomics into clinical practice. Appropriately designed randomized controlled trials generally provide the most robust evidence of the clinical utility, but often only data from a pharmacogenomic association study are available. This paper details a method for reframing the results of pharmacogenomic association studies in terms of the comparative treatment effect for a pharmacogenomic subgroup to provide greater insight into the likely clinical utility of a pharmacogenomic marker, its’ likely cost effectiveness, and the value of undertaking the further (often expensive) research required for translation into clinical practice. The method is based on the law of total probability, which relates marginal and conditional probability. It takes as inputs: the prevalence of the pharmacogenomic marker in the patient group of interest, prognostic effect of the pharmacogenomic marker based on observational association studies, and the unstratified comparative treatment effect based on one or more conventional randomized controlled trials. The critical assumption is that of exchangeability across the included studies. The method is demonstrated using a case study of cytochrome P450 (CYP) 2C19 genotype and the anti-platelet agent clopidogrel. Indirect subgroup analysis provided insight into relationship between the clinical utility of genotyping CYP2C19 and the risk ratio of cardiovascular outcomes between CYP2C19 genotypes for individuals using clopidogrel. In this case study the indirect and direct estimates of the treatment effect for the cytochrome P450 2C19 subgroups were similar. In general, however, indirect estimates are likely to have substantially greater risk of bias than an equivalent direct estimate. PMID:24015225

  20. Effects of roadside transect width on waterfowl and wetland estimates

    USGS Publications Warehouse

    Austin, Jane E.; Sklebar, H. Thomas; Guntenspergen, Glenn R.; Buhl, Thomas K.

    2000-01-01

    Strip transects located along roads are commonly used to estimate waterfowl populations and characterize associated wetland habitat. We used data collected in May and early June, 1995, on forty-five 40-km2 plots in North Dakota to evaluate bias of 800-m and 400-m wide roadside transects for sampling wetlands relative to a larger (40-km2) scale and to compare duck abundance at the two widths. Densities of all basins combined and of seasonal basins considered alone were biased high for both transect widths, but mean bias did not differ from zero for temporary or semipermanent basins. Biases did not occur when excavated seasonal and temporary basins (i.e., road ditches) were excluded from the sample. Mean basin density was higher for the inner (400-m) transect width than for the outer transect width (area remaining of the 800-m transect, outside of center 400-m width) for all basins combined and for seasonal and temporary basins. We detected an area-related bias in the occurrence of basins in transects: smaller basins (0.08–1.6 ha) were over-represented in transect samples by 2.9–6.5%, and larger basins (≥11 ha) were under-represented in 800-m transects by 7.3% and in 400-m transects by 16.3%. We compared the distribution of ducks relative to water conditions in the inner and outer transect widths to evaluate whether they were affected by proximity to the road. Mallards (Anas platyrhynchos L.), northern pintails (A. acuta L.), and gadwall (A. strepera L.) responded to water conditions equally in the inner and outer transect widths, but northern shovelers (A. clypeata L.) and blue-winged teal (A. discors L.) responded more strongly to wetlands on the inner than the outer transect width, indicating that estimates of these species would be higher from a 400-m wide transect than from an 800-m wide transect. Differences in an adjustment index, used to account for the portion of basin obscured from view, were highly variable between inner and outer transect widths but

  1. An investigation of numerical grid effects in parameter estimation.

    PubMed

    Zyvoloski, George A; Vesselinov, Velimir V

    2006-01-01

    Modern ground water characterization and remediation projects routinely require calibration and inverse analysis of large three-dimensional numerical models of complex hydrogeological systems. Hydrogeologic complexity can be prompted by various aquifer characteristics including complicated spatial hydrostratigraphy and aquifer recharge from infiltration through an unsaturated zone. To keep the numerical models computationally efficient, compromises are frequently made in the model development, particularly, about resolution of the computational grid and numerical representation of the governing flow equation. The compromise is required so that the model can be used in calibration, parameter estimation, performance assessment, and analysis of sensitivity and uncertainty in model predictions. However, grid properties and resolution as well as applied computational schemes can have large effects on forward-model predictions and on inverse parameter estimates. We investigate these effects for a series of one- and two-dimensional synthetic cases representing saturated and variably saturated flow problems. We show that "conformable" grids, despite neglecting terms in the numerical formulation, can lead to accurate solutions of problems with complex hydrostratigraphy. Our analysis also demonstrates that, despite slower computer run times and higher memory requirements for a given problem size, the control volume finite-element method showed an advantage over finite-difference techniques in accuracy of parameter estimation for a given grid resolution for most of the test problems.

  2. Estimating the Effect of Gypsy Moth Defloiation Using MODIS

    NASA Technical Reports Server (NTRS)

    deBeurs, K. M.; Townsend, P. A.

    2008-01-01

    The area of North American forests affected by gypsy moth defoliation continues to expand despite efforts to slow the spread. With the increased area of infestation, ecological, environmental and economic concerns about gypsy moth disturbance remain significant, necessitating coordinated, repeatable and comprehensive monitoring of the areas affected. In this study, our primary objective was to estimate the magnitude of defoliation using Moderate Resolution Imaging Spectroradiometer (MODIS) imagery for a gypsy moth outbreak that occurred in the US central Appalachian Mountains in 2000 and 2001. We focused on determining the appropriate spectral MODIS indices and temporal compositing method to best monitor the effects of gypsy moth defoliation. We tested MODIS-based Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Normalized Difference Water Index (NDWI), and two versions of the Normalized Difference Infrared index (NDIIb6 and NDIIb7, using the channels centered on 1640 nm and 2130 nm respectively) for their capacity to map defoliation as estimated by ground observations. In addition, we evaluated three temporal resolutions: daily, 8-day and 16-day data. We validated the results through quantitative comparison to Landsat based defoliation estimates and traditional sketch maps. Our MODIS based defoliation estimates based on NDIIb6 and NDIIb7 closely matched Landsat defoliation estimates derived from field data as well as sketch maps. We conclude that daily MODIS data can be used with confidence to monitor insect defoliation on an annual time scale, at least for larger patches (greater than 0.63 km2). Eight-day and 16-day MODIS composites may be of lesser use due to the ephemeral character of disturbance by the gypsy moth.

  3. Long-Term Large-Scale Bias-Adjusted Precipitation Estimates at High Spatial and Temporal Resolution Derived from the National Mosaic and Multi-Sensor QPE (NMQ/Q2) Precipitation Reanalysis over CONUS

    NASA Astrophysics Data System (ADS)

    Prat, O. P.; Nelson, B. R.; Stevens, S. E.; Seo, D. J.; Kim, B.

    2014-12-01

    The processing of radar-only precipitation via the reanalysis from the National Mosaic and Multi-Sensor Quantitative (NMQ/Q2) based on the WSR-88D Next-generation Radar (Nexrad) network over Continental United States (CONUS) is nearly completed for the period covering from 2000 to 2012. This important milestone constitutes a unique opportunity to study precipitation processes at a 1-km spatial resolution for a 5-min temporal resolution. However, in order to be suitable for hydrological, meteorological and climatological applications, the radar-only product needs to be bias-adjusted and merged with in-situ rain gauge information. Rain gauge networks such as the Hydrometeorological Automated Data System (HADS), the Automated Surface Observing Systems (ASOS), the Climate Reference Network (CRN), and the Global Historical Climatology Network - Daily (GHCN-D) are used to adjust for those biases and to merge with the radar only product to provide a multi-sensor estimate. The challenges related to incorporating non-homogeneous networks over a vast area and for a long-term record are enormous. Among the challenges we are facing are the difficulties incorporating differing resolution and quality surface measurements to adjust gridded estimates of precipitation. Another challenge is the type of adjustment technique. After assessing the bias and applying reduction or elimination techniques, we are investigating the kriging method and its variants such as simple kriging (SK), ordinary kriging (OK), and conditional bias-penalized Kriging (CBPK) among others. In addition we hope to generate estimates of uncertainty for the gridded estimate. In this work the methodology is presented as well as a comparison between the radar-only product and the final multi-sensor QPE product. The comparison is performed at various time scales from the sub-hourly, to annual. In addition, comparisons over the same period with a suite of lower resolution QPEs derived from ground based radar

  4. [Integral estimation of genetic effects of ionizing radiation].

    PubMed

    Shevchenko, V A

    1997-01-01

    A system of criteria (direct, indirect, extrapolational, integral, populational, evolutional) has been proposed to estimate the consequences of irradiation of flora, fauna and human population. This system makes it possible to obtain the most comprehensive estimate of genetic effects from exposure of live organisms to ionizing radiations. An attempt has been made to use extrapolational approaches for assessing the genetic risk on the basis of the results of cytogenetic examination of the human population in a number of regions exposed to the action of ionizing radiations as a result of the Chernobyl accident, in connection with the activity of the chemical plant Mayak in the Chelyabinsk region, nuclear explosions at the Semipalatinsk nuclear test site, the accident at the Three Mile Island nuclear power plant in the U.S.A. PMID:9599614

  5. Apollo video photogrammetry estimation of plume impingement effects

    NASA Astrophysics Data System (ADS)

    Immer, Christopher; Lane, John; Metzger, Philip; Clements, Sandra

    2011-07-01

    Future missions to the Moon may require numerous landings at the same site. Since the top few centimeters are loosely packed regolith, plume impingement from the Lander ejects the granular material at high velocities. Much work is needed to understand the physics of plume impingement during landing to protect hardware surrounding the landing sites. While mostly qualitative in nature, the Apollo Lunar Module landing videos can provide a wealth of quantitative information using modern photogrammetry techniques. The authors have used the digitized videos to quantify plume impingement effects of the landing exhaust on the lunar surface. The dust ejection angle from the plume is estimated at 1°-3°. The lofted particle density is estimated at 10 8-10 13 particles/m 3. Additionally, evidence for ejection of large 10-15 cm sized objects and a dependence of ejection angle on thrust are presented. Further work is ongoing to continue quantitative analysis of the landing videos.

  6. The Effect of Lidar Point Density on LAI Estimation

    NASA Astrophysics Data System (ADS)

    Cawse-Nicholson, K.; van Aardt, J. A.; Romanczyk, P.; Kelbe, D.; Bandyopadhyay, M.; Yao, W.; Krause, K.; Kampe, T. U.

    2013-12-01

    Leaf Area Index (LAI) is an important measure of forest health, biomass and carbon exchange, and is most commonly defined as the ratio of the leaf area to ground area. LAI is understood over large spatial scales and describes leaf properties over an entire forest, thus airborne imagery is ideal for capturing such data. Spectral metrics such as the normalized difference vegetation index (NDVI) have been used in the past for LAI estimation, but these metrics may saturate for high LAI values. Light detection and ranging (lidar) is an active remote sensing technology that emits light (most often at the wavelength 1064nm) and uses the return time to calculate the distance to intercepted objects. This yields information on three-dimensional structure and shape, which has been shown in recent studies to yield more accurate LAI estimates than NDVI. However, although lidar is a promising alternative for LAI estimation, minimum acquisition parameters (e.g. point density) required for accurate LAI retrieval are not yet well known. The objective of this study was to determine the minimum number of points per square meter that are required to describe the LAI measurements taken in-field. As part of a larger data collect, discrete lidar data were acquired by Kucera International Inc. over the Hemlock-Canadice State Forest, NY, USA in September 2012. The Leica ALS60 obtained point density of 12 points per square meter and effective ground sampling distance (GSD) of 0.15m. Up to three returns with intensities were recorded per pulse. As part of the same experiment, an AccuPAR LP-80 was used to collect LAI estimates at 25 sites on the ground. Sites were spaced approximately 80m apart and nine measurements were made in a grid pattern within a 20 x 20m site. Dominant species include Hemlock, Beech, Sugar Maple and Oak. This study has the benefit of very high-density data, which will enable a detailed map of intra-forest LAI. Understanding LAI at fine scales may be particularly useful

  7. A brief review of the estimated economic burden of sexually transmitted diseases in the United States: inflation-adjusted updates of previously published cost studies.

    PubMed

    Chesson, Harrell W; Gift, Thomas L; Owusu-Edusei, Kwame; Tao, Guoyu; Johnson, Ana P; Kent, Charlotte K

    2011-10-01

    We conducted a literature review of studies of the economic burden of sexually transmitted diseases in the United States. The annual direct medical cost of sexually transmitted diseases (including human immunodeficiency virus) has been estimated to be $16.9 billion (range: $13.9-$23.0 billion) in 2010 US dollars.

  8. Accounting for Outcome Misclassification in Estimates of the Effect of Occupational Asbestos Exposure on Lung Cancer Death

    PubMed Central

    Edwards, Jessie K.; Cole, Stephen R.; Chu, Haitao; Olshan, Andrew F.; Richardson, David B.

    2014-01-01

    In studies of the health effects of asbestos, lung cancer death is subject to misclassification. We used modified maximum likelihood to explore the effects of outcome misclassification on the rate ratio of lung cancer death per 100 fiber-years per milliliter of cumulative asbestos exposure in a cohort study of textile workers in Charleston, South Carolina, followed from 1940 to 2001. The standard covariate-adjusted estimate of the rate ratio was 1.94 (95% confidence interval: 1.55, 2.44), and modified maximum likelihood produced similar results when we assumed that the specificity of outcome classification was 0.98. With sensitivity assumed to be 0.80 and specificity assumed to be 0.95, estimated rate ratios were further from the null and less precise (rate ratio = 2.17; 95% confidence interval: 1.59, 2.98). In the present context, standard estimates for the effect of asbestos on lung cancer death were similar to estimates accounting for the limited misclassification. However, sensitivity analysis using modified maximum likelihood was needed to verify the robustness of standard estimates, and this approach will provide unbiased estimates in settings with more misclassification. PMID:24352593

  9. Accounting for outcome misclassification in estimates of the effect of occupational asbestos exposure on lung cancer death.

    PubMed

    Edwards, Jessie K; Cole, Stephen R; Chu, Haitao; Olshan, Andrew F; Richardson, David B

    2014-03-01

    In studies of the health effects of asbestos, lung cancer death is subject to misclassification. We used modified maximum likelihood to explore the effects of outcome misclassification on the rate ratio of lung cancer death per 100 fiber-years per milliliter of cumulative asbestos exposure in a cohort study of textile workers in Charleston, South Carolina, followed from 1940 to 2001. The standard covariate-adjusted estimate of the rate ratio was 1.94 (95% confidence interval: 1.55, 2.44), and modified maximum likelihood produced similar results when we assumed that the specificity of outcome classification was 0.98. With sensitivity assumed to be 0.80 and specificity assumed to be 0.95, estimated rate ratios were further from the null and less precise (rate ratio = 2.17; 95% confidence interval: 1.59, 2.98). In the present context, standard estimates for the effect of asbestos on lung cancer death were similar to estimates accounting for the limited misclassification. However, sensitivity analysis using modified maximum likelihood was needed to verify the robustness of standard estimates, and this approach will provide unbiased estimates in settings with more misclassification.

  10. Adjustment of interaural time difference in head related transfer functions based on listeners' anthropometry and its effect on sound localization

    NASA Astrophysics Data System (ADS)

    Suzuki, Yôiti; Watanabe, Kanji; Iwaya, Yukio; Gyoba, Jiro; Takane, Shouichi

    2005-04-01

    Because the transfer functions governing subjective sound localization (HRTFs) show strong individuality, sound localization systems based on synthesis of HRTFs require suitable HRTFs for individual listeners. However, it is impractical to obtain HRTFs for all listeners based on measurements. Improving sound localization by adjusting non-individualized HRTFs to a specific listener based on that listener's anthropometry might be a practical method. This study first developed a new method to estimate interaural time differences (ITDs) using HRTFs. Then correlations between ITDs and anthropometric parameters were analyzed using the canonical correlation method. Results indicated that parameters relating to head size, and shoulder and ear positions are significant. Consequently, it was attempted to express ITDs based on listener's anthropometric data. In this process, the change of ITDs as a function of azimuth angle was parameterized as a sum of sine functions. Then the parameters were analyzed using multiple regression analysis, in which the anthropometric parameters were used as explanatory variables. The predicted or individualized ITDs were installed in the nonindividualized HRTFs to evaluate sound localization performance. Results showed that individualization of ITDs improved horizontal sound localization.

  11. Estimating rotavirus vaccine effectiveness in Japan using a screening method

    PubMed Central

    Araki, Kaoru; Hara, Megumi; Sakanishi, Yuta; Shimanoe, Chisato; Nishida, Yuichiro; Matsuo, Muneaki; Tanaka, Keitaro

    2016-01-01

    abstract Rotavirus gastroenteritis is a highly contagious, acute viral disease that imposes a significant health burden worldwide. In Japan, rotavirus vaccines have been commercially available since 2011 for voluntary vaccination, but vaccine coverage and effectiveness have not been evaluated. In the absence of a vaccination registry in Japan, vaccination coverage in the general population was estimated according to the number of vaccines supplied by the manufacturer, the number of children who received financial support for vaccination, and the size of the target population. Patients with rotavirus gastroenteritis were identified by reviewing the medical records of all children who consulted 6 major hospitals in Saga Prefecture with gastroenteritis symptoms. Vaccination status among these patients was investigated by reviewing their medical records or interviewing their guardians by telephone. Vaccine effectiveness was determined using a screening method. Vaccination coverage increased with time, and it was 2-times higher in municipalities where the vaccination fee was supported. In the 2012/13 season, vaccination coverage in Saga Prefecture was 14.9% whereas the proportion of patients vaccinated was 5.1% among those with clinically diagnosed rotavirus gastroenteritis and 1.9% among those hospitalized for rotavirus gastroenteritis. Thus, vaccine effectiveness was estimated as 69.5% and 88.8%, respectively. This is the first study to evaluate rotavirus vaccination coverage and effectiveness in Japan since vaccination began. PMID:26680277

  12. Effect of survey design and catch rate estimation on total catch estimates in Chinook salmon fisheries

    USGS Publications Warehouse

    McCormick, Joshua L.; Quist, Michael C.; Schill, Daniel J.

    2012-01-01

    Roving–roving and roving–access creel surveys are the primary techniques used to obtain information on harvest of Chinook salmon Oncorhynchus tshawytscha in Idaho sport fisheries. Once interviews are conducted using roving–roving or roving–access survey designs, mean catch rate can be estimated with the ratio-of-means (ROM) estimator, the mean-of-ratios (MOR) estimator, or the MOR estimator with exclusion of short-duration (≤0.5 h) trips. Our objective was to examine the relative bias and precision of total catch estimates obtained from use of the two survey designs and three catch rate estimators for Idaho Chinook salmon fisheries. Information on angling populations was obtained by direct visual observation of portions of Chinook salmon fisheries in three Idaho river systems over an 18-d period. Based on data from the angling populations, Monte Carlo simulations were performed to evaluate the properties of the catch rate estimators and survey designs. Among the three estimators, the ROM estimator provided the most accurate and precise estimates of mean catch rate and total catch for both roving–roving and roving–access surveys. On average, the root mean square error of simulated total catch estimates was 1.42 times greater and relative bias was 160.13 times greater for roving–roving surveys than for roving–access surveys. Length-of-stay bias and nonstationary catch rates in roving–roving surveys both appeared to affect catch rate and total catch estimates. Our results suggest that use of the ROM estimator in combination with an estimate of angler effort provided the least biased and most precise estimates of total catch for both survey designs. However, roving–access surveys were more accurate than roving–roving surveys for Chinook salmon fisheries in Idaho.

  13. Detailed Report on 2014/15 Influenza Virus Characteristics, and Estimates on Influenza Virus Vaccine Effectiveness from Austria’s Sentinel Physician Surveillance Network

    PubMed Central

    2016-01-01

    Background Influenza vaccine effectiveness (VE) is influenced by the antigenic similarity between vaccine- and circulating strains. Material and Methods This paper presents data obtained by the Austrian sentinel surveillance system on the evolution of influenza viruses during the season 2014/15 and its impact on influenza vaccine effectiveness in primary care in Austria as estimated by a test-negative case control design. VE estimates were performed for each influenza virus type/subtype, stratified by underlying diseases and adjusted for age, sex and calendar week of infection. Results Detailed genetic and antigenic analyses showed that circulating A(H3N2) viruses were genetically distinct from the 2014/15 A(H3N2) vaccine component indicating a profound vaccine mismatch. The Influenza A(H1N1)pdm09 viruses were antigenically conserved and matched the respective vaccine component. Influenza B viruses were lineage-matched B/Yamagata viruses with a clade-level variation. Consistent with substantial vaccine mismatch for the A(H3N2) viruses a crude overall VE of only 47% was estimated, whereas the VE estimates for A(H1N1)pdm09 were 84% and for influenza B viruses 70%. Increased VE estimates were obtained after stratification by underlying diseases and adjustment for the covariates sex and age, whereby the adjustment for the calendar week of infection was the covariate exerting the highest influence on adjusted VE estimates. Conclusion In summary, VE data obtained in this study underscore the importance to perform VE estimates in the context of detailed characterization of the contributing viruses and also demonstrate that the calendar week of influenza virus infection is the most important confounder of VE estimates. PMID:26975056

  14. Bayesian Estimation of Small Effects in Exercise and Sports Science.

    PubMed

    Mengersen, Kerrie L; Drovandi, Christopher C; Robert, Christian P; Pyne, David B; Gore, Christopher J

    2016-01-01

    The aim of this paper is to provide a Bayesian formulation of the so-called magnitude-based inference approach to quantifying and interpreting effects, and in a case study example provide accurate probabilistic statements that correspond to the intended magnitude-based inferences. The model is described in the context of a published small-scale athlete study which employed a magnitude-based inference approach to compare the effect of two altitude training regimens (live high-train low (LHTL), and intermittent hypoxic exposure (IHE)) on running performance and blood measurements of elite triathletes. The posterior distributions, and corresponding point and interval estimates, for the parameters and associated effects and comparisons of interest, were estimated using Markov chain Monte Carlo simulations. The Bayesian analysis was shown to provide more direct probabilistic comparisons of treatments and able to identify small effects of interest. The approach avoided asymptotic assumptions and overcame issues such as multiple testing. Bayesian analysis of unscaled effects showed a probability of 0.96 that LHTL yields a substantially greater increase in hemoglobin mass than IHE, a 0.93 probability of a substantially greater improvement in running economy and a greater than 0.96 probability that both IHE and LHTL yield a substantially greater improvement in maximum blood lactate concentration compared to a Placebo. The conclusions are consistent with those obtained using a 'magnitude-based inference' approach that has been promoted in the field. The paper demonstrates that a fully Bayesian analysis is a simple and effective way of analysing small effects, providing a rich set of results that are straightforward to interpret in terms of probabilistic statements. PMID:27073897

  15. Bayesian Estimation of Small Effects in Exercise and Sports Science.

    PubMed

    Mengersen, Kerrie L; Drovandi, Christopher C; Robert, Christian P; Pyne, David B; Gore, Christopher J

    2016-01-01

    The aim of this paper is to provide a Bayesian formulation of the so-called magnitude-based inference approach to quantifying and interpreting effects, and in a case study example provide accurate probabilistic statements that correspond to the intended magnitude-based inferences. The model is described in the context of a published small-scale athlete study which employed a magnitude-based inference approach to compare the effect of two altitude training regimens (live high-train low (LHTL), and intermittent hypoxic exposure (IHE)) on running performance and blood measurements of elite triathletes. The posterior distributions, and corresponding point and interval estimates, for the parameters and associated effects and comparisons of interest, were estimated using Markov chain Monte Carlo simulations. The Bayesian analysis was shown to provide more direct probabilistic comparisons of treatments and able to identify small effects of interest. The approach avoided asymptotic assumptions and overcame issues such as multiple testing. Bayesian analysis of unscaled effects showed a probability of 0.96 that LHTL yields a substantially greater increase in hemoglobin mass than IHE, a 0.93 probability of a substantially greater improvement in running economy and a greater than 0.96 probability that both IHE and LHTL yield a substantially greater improvement in maximum blood lactate concentration compared to a Placebo. The conclusions are consistent with those obtained using a 'magnitude-based inference' approach that has been promoted in the field. The paper demonstrates that a fully Bayesian analysis is a simple and effective way of analysing small effects, providing a rich set of results that are straightforward to interpret in terms of probabilistic statements.

  16. Bayesian Estimation of Small Effects in Exercise and Sports Science

    PubMed Central

    Mengersen, Kerrie L.; Drovandi, Christopher C.; Robert, Christian P.; Pyne, David B.; Gore, Christopher J.

    2016-01-01

    The aim of this paper is to provide a Bayesian formulation of the so-called magnitude-based inference approach to quantifying and interpreting effects, and in a case study example provide accurate probabilistic statements that correspond to the intended magnitude-based inferences. The model is described in the context of a published small-scale athlete study which employed a magnitude-based inference approach to compare the effect of two altitude training regimens (live high-train low (LHTL), and intermittent hypoxic exposure (IHE)) on running performance and blood measurements of elite triathletes. The posterior distributions, and corresponding point and interval estimates, for the parameters and associated effects and comparisons of interest, were estimated using Markov chain Monte Carlo simulations. The Bayesian analysis was shown to provide more direct probabilistic comparisons of treatments and able to identify small effects of interest. The approach avoided asymptotic assumptions and overcame issues such as multiple testing. Bayesian analysis of unscaled effects showed a probability of 0.96 that LHTL yields a substantially greater increase in hemoglobin mass than IHE, a 0.93 probability of a substantially greater improvement in running economy and a greater than 0.96 probability that both IHE and LHTL yield a substantially greater improvement in maximum blood lactate concentration compared to a Placebo. The conclusions are consistent with those obtained using a ‘magnitude-based inference’ approach that has been promoted in the field. The paper demonstrates that a fully Bayesian analysis is a simple and effective way of analysing small effects, providing a rich set of results that are straightforward to interpret in terms of probabilistic statements. PMID:27073897

  17. Using Dynamical Adjustment to Estimate the Anthropogenically-forced Response of Surface Temperature and Precipitation within a High-resolution Regional Climate Model: A Case Study of the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Siler, N.; Roe, G.

    2014-12-01

    One of the greatest challenges in regional climate prediction is distinguishing the anthropogenically-forced response from low-frequency internal variability. In a large ensemble, the forced response is well approximated by the mean trend of the ensemble members. However, in mountainous regions like the Pacific Northwest, very high model resolution is required to accurately represent the terrain, making large ensembles prohibitively expensive. Here we take a different approach, employing a statistical technique called "dynamical adjustment" to estimate the forced response of wintertime (DJF) surface temperature and precipitation within two high-resolution simulations of the 21st-century climate in the Pacific Northwest. The simulations were performed at 12-km resolution using the Weather Research and Forecasting Model, downscaled from global CCSM3 and ECHAM5 simulations under an A1B emissions scenario. While the raw simulations exhibit large differences in the magnitude and spatial structure of precipitation and surface temperature trends, dynamical adjustment results in much better agreement between the simulations, especially with regard to projected surface warming. These results suggest that dynamical adjustment of a small number of high-resolution simulations can provide much of the benefit of a large ensemble, but at far less computational expense.

  18. Roth versus MBT: does bracket prescription have an effect on the subjective outcome of pre-adjusted edgewise treatment?

    PubMed

    Moesi, Bopelo; Dyer, Fiona; Benson, Philip E

    2013-04-01

    The aim was to determine if bracket prescription has any effect on the subjective outcome of pre-adjusted edgewise treatment as judged by professionals. This retrospective observational assessment study was undertaken in the Orthodontic Department of the Charles Clifford Dental Hospital, Sheffield, UK. Forty sets of post-treatment study models from patients treated using a pre-adjusted edgewise appliance (20 Roth and 20 MBT) were selected. The models were masked and shown in a random order to nine experienced orthodontic clinicians, who were asked to assess the quality of the outcome, using a pre-piloted questionnaire. The principal outcome measure was the Incisor and Canine Aesthetic Torque and Tip (ICATT) score for each of the 40 post-treatment models carried out by the nine judges. A two-way analysis of variance was undertaken with the dependent variable, total ICATT score and independent variables, Bracket prescription (Roth or MBT) and Assessor. There were statistically significant differences between the subjective assessments of the nine judges (P<0.001), but there was no statistically significant difference between the two bracket prescriptions (P = 0.900). The best agreement between a clinician's judgment of prescription used and the actual prescription was fair (kappa statistic 0.25; CI -0.05 to 0.55). The ability to determine which bracket prescription was used was no better than chance for the majority of clinicians. Bracket prescription had no effect on the subjective aesthetic judgments of post-treatment study models made by nine experienced orthodontists.

  19. An analytical approach to estimate curvature effect of coseismic deformations

    NASA Astrophysics Data System (ADS)

    Dong, Jie; Sun, Wenke; Zhou, Xin; Wang, Rongjiang

    2016-08-01

    We present an analytical approach to compute the curvature effect by the new analytical solutions of coseismic deformation derived for the homogeneous sphere model. We consider two spheres with different radii: one is the same as earth and the other with a larger radius can approximate a half-space model. Then, we calculate the coseismic displacements for the two spheres and define the relative percentage of the displacements as the curvature effect. The near-field curvature effect is defined relative to the maximum coseismic displacement. The results show that the maximum curvature effect is about 4 per cent for source depths of less than 100 km, and about 30 per cent for source depths of less than 600 km. For the far-field curvature effect, we define it relative to the observing point. The curvature effect is extremely large and sometimes exceeds 100 per cent. Moreover, this new approach can be used to estimate any planet's curvature effect quantitatively. For a smaller sphere, such as the Moon, the curvature effect is much larger than that of the Earth, with an inverse ratio to the earth's radius.

  20. Longitudinal Effects of Teacher and Student Perceptions of Teacher-Student Relationship Qualities on Academic Adjustment

    PubMed Central

    Hughes, Jan N.

    2010-01-01

    The shared and unique effects of teacher and student reports of teacher student relationship quality (TSRQ) in second and third grade on academic self views, behavioral engagement, and achievement the following year were investigated in a sample of 714 academically at-risk students. Teacher and student reports of teacher-student support and conflict showed low correspondence. As a block, teacher and student reports of TSRQ predicted all outcomes, above prior performance on that outcome and background variables. Student reports uniquely predicted school belonging, perceived academic competence, and math achievement. Teacher reports uniquely predicted behavioral engagement and child perceived academic competence. Teacher and student reports of the teacher-student relationship assess largely different constructs that predict different outcomes. Implications of findings for practice and research are discussed. PMID:21984843

  1. How do clarinet players adjust the resonances of their vocal tracts for different playing effects?

    NASA Astrophysics Data System (ADS)

    Fritz, Claudia; Wolfe, Joe

    2005-11-01

    In a simple model, the reed of the clarinet is mechanically loaded by the series combination of the acoustical impedances of the instrument itself and of the player's airway. Here we measure the complex impedance spectrum of players' airways using an impedance head adapted to fit inside a clarinet mouthpiece. A direct current shunt with high acoustical resistance allows players to blow normally, so the players can simulate the tract condition under playing conditions. The reproducibility of the results suggest that the players' ``muscle memory'' is reliable for this task. Most players use a single, highly stable vocal tract configuration over most of the playing range, except for the altissimo register. However, this ``normal'' configuration varies substantially among musicians. All musicians change the configuration, often drastically for ``special effects'' such as glissandi and slurs: the tongue is lowered and the impedance magnitude reduced when the player intends to lower the pitch or to slur downwards, and vice versa.

  2. Effects of chundosunbup Qi-training on psychological adjustments: a cross-sectional study.

    PubMed

    Lee, M S; Jeong, S M; Oh, S W; Ryu, H; Chung, H T

    1998-01-01

    This cross-sectional investigation evaluated the trend of psychological changes by ChunDoSunBup (CDSB) Qi-training using a self-report inventory of emotional distress, Symptom Check List-90-Revision (SCL-90-R). 41 normal healthy subjects (mean age = 20.98 +/- 5.39) and 123 CDSB Qi-trainees (divided into three groups, Q1, Q2 and Q3) participated in this study. Group Q1 has received 1-4 months CDSB Qi-training (age 21.95 +/- 7.82, n = 41); Q2 has 5-12 months Qi-training (age 20.0 +/- 7.75, n = 41); and Q3 has more than 13 months Qi-training (age 22.68 +/- 6.72, n = 41). Our results show that Qi-trainees over 13 months had significantly lower scores compared to controls. A significant negative correlation was found between the Qi-training period and all SCL-90-R subscales except phobic anxiety. These results suggest that CDSB Qi-training is effective in protection as well as reduction of psychological symptomatology.

  3. An adjustment of benthic ecological quality assessment to effects of salinity.

    PubMed

    Fleischer, Dirk; Zettler, Michael L

    2009-08-01

    In the last decade a politically inspired marine protection movement arose in the European Union. This movement leads to an holistic strategy. Merging the Water Framework Directive (WFD) and the Marine Strategy Directive (MSD) along the European coastline demands sophisticated ecological classification procedures. The 'Benthic Quality Index' (BQI) is one of several indices created in view of the WFD. We used the dynamic species reference system ES(50)(0.05) to test the capability of BQI to exclude primary environmental factors including the salinity gradient and depth (a proxy for the oxygen regime) from the ecological quality (EcoQ) assessment. A macrozoobenthos dataset of the southern Baltic Sea spreading over more than 20 years and over 100,000 km2 was used for the EcoQ assessment. Quality assurance rules were applied to the record set and an analytical dataset of 936 sampling events with 20,451 abundance records was used in the analysis. We show that the natural salinity gradient has a severe impact on the BQI based EcoQ. We adapted the calculation procedure to reduce the salinity effects to a minimum. According to the adaptation 503 sensitivity/tolerance values for 87 species were computed. These values were calculated within seven salinity ranges from 0 to >30 PSU and two depth zones. These values can be used as a reference for further investigation in the Baltic and other areas with similar environmental conditions. PMID:19084875

  4. Estimating Potential Effects of Hypothetical Oil Spills on Polar Bears

    USGS Publications Warehouse

    Amstrup, Steven C.; Durner, G.M.; McDonald, T.L.; Johnson, W.R.

    2006-01-01

    Much is known about the transport and fate of oil spilled into the sea and its toxicity to exposed wildlife. Previously, however, there has been no way to quantify the probability that wildlife dispersed over the seascape would be exposed to spilled oil. Polar bears, the apical predator of the arctic, are widely dispersed near the continental shelves of the Arctic Ocean, an area also undergoing considerable hydrocarbon exploration and development. We used 15,308 satellite locations from 194 radiocollared polar bears to estimate the probability that polar bears could be exposed to hypothetical oil spills. We used a true 2 dimensional Gausian kernel density estimator, to estimate the number of bears likely to occur in each 1.00 km2 cell of a grid superimposed over near shore areas surrounding 2 oil production facilities: the existing Northstar oil production facility, and the proposed offshore site for the Liberty production facility. We estimated the standard errors of bear numbers per cell with bootstrapping. Simulated oil spill footprints for September and October, the times during which we hypothesized effects of an oil-spill would be worst, were estimated using real wind and current data collected between 1980 and 1996. We used ARC/Info software to calculate overlap (numbers of bears oiled) between simulated oil-spill footprints and polar bear grid-cell values. Numbers of bears potentially oiled by a hypothetical 5912 barrel spill (the largest spill thought probable from a pipeline breach) ranged from 0 to 27 polar bears for September open water conditions, and from 0 to 74 polar bears in October mixed ice conditions. Median numbers oiled by the 5912 barrel hypothetical spill from the Liberty simulation in September and October were 1 and 3 bears, equivalent values for the Northstar simulation were 3 and 11 bears. In October, 75% of trajectories from the 5912 barrel simulated spill at Liberty oiled 9 or fewer bears while 75% of the trajectories affected 20 or

  5. Modeling Quality-Adjusted Life Expectancy Loss Resulting from Tobacco Use in the United States

    ERIC Educational Resources Information Center

    Kaplan, Robert M.; Anderson, John P.; Kaplan, Cameron M.

    2007-01-01

    Purpose: To describe the development of a model for estimating the effects of tobacco use upon Quality Adjusted Life Years (QALYs) and to estimate the impact of tobacco use on health outcomes for the United States (US) population using the model. Method: We obtained estimates of tobacco consumption from 6 years of the National Health Interview…

  6. Estimation of effective connectivity via data-driven neural modeling

    PubMed Central

    Freestone, Dean R.; Karoly, Philippa J.; Nešić, Dragan; Aram, Parham; Cook, Mark J.; Grayden, David B.

    2014-01-01

    This research introduces a new method for functional brain imaging via a process of model inversion. By estimating parameters of a computational model, we are able to track effective connectivity and mean membrane potential dynamics that cannot be directly measured using electrophysiological measurements alone. The ability to track the hidden aspects of neurophysiology will have a profound impact on the way we understand and treat epilepsy. For example, under the assumption the model captures the key features of the cortical circuits of interest, the framework will provide insights into seizure initiation and termination on a patient-specific basis. It will enable investigation into the effect a particular drug has on specific neural populations and connectivity structures using minimally invasive measurements. The method is based on approximating brain networks using an interconnected neural population model. The neural population model is based on a neural mass model that describes the functional activity of the brain, capturing the mesoscopic biophysics and anatomical structure. The model is made subject-specific by estimating the strength of intra-cortical connections within a region and inter-cortical connections between regions using a novel Kalman filtering method. We demonstrate through simulation how the framework can be used to track the mechanisms involved in seizure initiation and termination. PMID:25506315

  7. Estimating Effects of Species Interactions on Populations of Endangered Species.

    PubMed

    Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

    2016-04-01

    Global change causes community composition to change considerably through time, with ever-new combinations of interacting species. To study the consequences of newly established species interactions, one available source of data could be observational surveys from biodiversity monitoring. However, approaches using observational data would need to account for niche differences between species and for imperfect detection of individuals. To estimate population sizes of interacting species, we extended N-mixture models that were developed to estimate true population sizes in single species. Simulations revealed that our model is able to disentangle direct effects of dominant on subordinate species from indirect effects of dominant species on detection probability of subordinate species. For illustration, we applied our model to data from a Swiss amphibian monitoring program and showed that sizes of expanding water frog populations were negatively related to population sizes of endangered yellow-bellied toads and common midwife toads and partly of natterjack toads. Unlike other studies that analyzed presence and absence of species, our model suggests that the spread of water frogs in Central Europe is one of the reasons for the decline of endangered toad species. Thus, studying population impacts of dominant species on population sizes of endangered species using data from biodiversity monitoring programs should help to inform conservation policy and to decide whether competing species should be subject to population management. PMID:27028074

  8. Estimating Effects of Species Interactions on Populations of Endangered Species.

    PubMed

    Roth, Tobias; Bühler, Christoph; Amrhein, Valentin

    2016-04-01

    Global change causes community composition to change considerably through time, with ever-new combinations of interacting species. To study the consequences of newly established species interactions, one available source of data could be observational surveys from biodiversity monitoring. However, approaches using observational data would need to account for niche differences between species and for imperfect detection of individuals. To estimate population sizes of interacting species, we extended N-mixture models that were developed to estimate true population sizes in single species. Simulations revealed that our model is able to disentangle direct effects of dominant on subordinate species from indirect effects of dominant species on detection probability of subordinate species. For illustration, we applied our model to data from a Swiss amphibian monitoring program and showed that sizes of expanding water frog populations were negatively related to population sizes of endangered yellow-bellied toads and common midwife toads and partly of natterjack toads. Unlike other studies that analyzed presence and absence of species, our model suggests that the spread of water frogs in Central Europe is one of the reasons for the decline of endangered toad species. Thus, studying population impacts of dominant species on population sizes of endangered species using data from biodiversity monitoring programs should help to inform conservation policy and to decide whether competing species should be subject to population management.

  9. Tools and techniques for estimating high intensity RF effects

    NASA Technical Reports Server (NTRS)

    Zacharias, Richard L.; Pennock, Steve T.; Poggio, Andrew J.; Ray, Scott L.

    1992-01-01

    Tools and techniques for estimating and measuring coupling and component disturbance for avionics and electronic controls are described. A finite-difference-time-domain (FD-TD) modeling code, TSAR, used to predict coupling is described. This code can quickly generate a mesh model to represent the test object. Some recent applications as well as the advantages and limitations of using such a code are described. Facilities and techniques for making low-power coupling measurements and for making direct injection test measurements of device disturbance are also described. Some scaling laws for coupling and device effects are presented. A method for extrapolating these low-power test results to high-power full-system effects are presented.

  10. Long-Term Effects of Incestuous Child Abuse in College Women: Social Adjustment, Social Cognition, and Family Characteristics.

    ERIC Educational Resources Information Center

    Harter, Stephanie; And Others

    1988-01-01

    Investigated family and social cognitive characteristics as mediators of social adjustment among college women. Indicated decreased cohesion and adaptability in the family of origin, increased perception of social isolation, and poorer social adjustment among subjects abused as children. Family characteristics and especially increased perceptions…

  11. Shrinkage Estimation of Varying Covariate Effects Based On Quantile Regression

    PubMed Central

    Peng, Limin; Xu, Jinfeng; Kutner, Nancy

    2013-01-01

    Varying covariate effects often manifest meaningful heterogeneity in covariate-response associations. In this paper, we adopt a quantile regression model that assumes linearity at a continuous range of quantile levels as a tool to explore such data dynamics. The consideration of potential non-constancy of covariate effects necessitates a new perspective for variable selection, which, under the assumed quantile regression model, is to retain variables that have effects on all quantiles of interest as well as those that influence only part of quantiles considered. Current work on l1-penalized quantile regression either does not concern varying covariate effects or may not produce consistent variable selection in the presence of covariates with partial effects, a practical scenario of interest. In this work, we propose a shrinkage approach by adopting a novel uniform adaptive LASSO penalty. The new approach enjoys easy implementation without requiring smoothing. Moreover, it can consistently identify the true model (uniformly across quantiles) and achieve the oracle estimation efficiency. We further extend the proposed shrinkage method to the case where responses are subject to random right censoring. Numerical studies confirm the theoretical results and support the utility of our proposals. PMID:25332515

  12. Aerosol direct radiative effect over China estimated with visibility measurements

    NASA Astrophysics Data System (ADS)

    Ye, K.; Lin, J.

    2012-12-01

    As a short-lived climate forcer, aerosols exhibit strong radiative effects that vary significantly across the space and time. Current understanding of the long-term variability of aerosol climate forcings is however very poor due to lack of relevant atmospheric measurements. Historic records for visibility measurements from thousands of ground meteorological stations offer a plausible tool to study the decadal and multi-decadal variability of aerosol radiative effects. As a first step, this study presents a method to estimate aerosol direct radiative effect over China based on visibility data for 2006. Visibility data from about 400 ground stations are converted to near-surface aerosol extinction coefficients, which are converted then to aerosol optical depth (AOD) based on spatially and temporally varying vertical distributions of aerosol optical properties simulated by the widely used chemical transport model GEOS-Chem. The resulting AOD data are consistent with direct measurements from the China Aerosol Remote Sensing Network (CARSNET) and the Aerosol Robotic Network (AERONET) in regions where visibility and AOD measurement sites are close in distance. Next, the visibility-derived AOD data are combined with other aerosol optical properties adopted from GEOS-Chem, cloud data from ground stations and surface albedo data from moderate-resolution imaging spectroradiometer (MODIS) to derive the direct radiative effect, by employing the Santa Barbara DISORT Atmospheric Radiative Transfer model (SBDART). Spatial and monthly variations of aerosol radiative effects are examined.

  13. Persistent sex-by-environment effects on offspring fitness and sex-ratio adjustment in a wild bird population

    PubMed Central

    Bowers, E. Keith; Thompson, Charles F.; Sakaluk, Scott K.

    2014-01-01

    Summary A major component of sex-allocation theory, the Trivers-Willard Model (TWM), posits that sons and daughters are differentially affected by variation in the rearing environment. In many species, the amount of parental care received is expected to have differing effects on the fitness of males and females. When this occurs, the TWM predicts that selection should favour adjustment of the offspring sex ratio in relation to the expected fitness return from offspring. However, evidence for sex-by-environment effects is mixed and little is known about the adaptive significance of producing either sex. Here, we test whether offspring sex ratios vary according to predictions of the TWM in the house wren (Troglodytes aedon, Vieillot). We also test the assumption of a sex-by-environment effect on offspring using two experiments, one in which we manipulated age-differences among nestlings within broods, and another in which we held nestling age constant but manipulated brood size. As predicted, females with high investment ability over-produced sons relative to those with lower ability. Males were also over-produced early within breeding seasons. In our experiments, the body mass of sons was more strongly affected by the sibling-competitive environment and resource availability than that of daughters: males grew heavier than females when reared in good conditions but were lighter than females when in poor conditions. Parents rearing broods with 1:1 sex ratios were more productive than parents rearing broods biased more strongly towards sons or daughters, suggesting that selection favours the production of mixed-sex broods. However, differences in the condition of offspring as neonates persisted to adulthood, and their reproductive success as adults varied with the body mass of sons, but not daughters, prior to independence from parental care. Thus, selection should favour slight but predictable variations in the sex ratio in relation to the quality of offspring that

  14. Persistent sex-by-environment effects on offspring fitness and sex-ratio adjustment in a wild bird population.

    PubMed

    Bowers, E Keith; Thompson, Charles F; Sakaluk, Scott K

    2015-03-01

    A major component of sex-allocation theory, the Trivers-Willard model (TWM), posits that sons and daughters are differentially affected by variation in the rearing environment. In many species, the amount of parental care received is expected to have differing effects on the fitness of males and females. When this occurs, the TWM predicts that selection should favour adjustment of the offspring sex ratio in relation to the expected fitness return from offspring. However, evidence for sex-by-environment effects is mixed, and little is known about the adaptive significance of producing either sex. Here, we test whether offspring sex ratios vary according to predictions of the TWM in the house wren (Troglodytes aedon, Vieillot). We also test the assumption of a sex-by-environment effect on offspring using two experiments, one in which we manipulated age differences among nestlings within broods, and another in which we held nestling age constant but manipulated brood size. As predicted, females with high investment ability overproduced sons relative to those with lower ability. Males were also overproduced early within breeding seasons. In our experiments, the body mass of sons was more strongly affected by the sibling-competitive environment and resource availability than that of daughters: males grew heavier than females when reared in good conditions but were lighter than females when in poor conditions. Parents rearing broods with 1:1 sex ratios were more productive than parents rearing broods biased more strongly towards sons or daughters, suggesting that selection favours the production of mixed-sex broods. However, differences in the condition of offspring as neonates persisted to adulthood, and their reproductive success as adults varied with the body mass of sons, but not daughters, prior to independence from parental care. Thus, selection should favour slight but predictable variations in the sex ratio in relation to the quality of offspring that parents are

  15. Lithosphere and upper-mantle structure of the southern Baltic Sea estimated from modelling relative sea-level data with glacial isostatic adjustment

    NASA Astrophysics Data System (ADS)

    Steffen, H.; Kaufmann, G.; Lampe, R.

    2014-06-01

    thickness as determined with ICE-5G does not agree with the lithosphere models. Hence, more investigations have to be undertaken to sufficiently determine structures such as the Ringkøbing-Fyn High as seen with seismics with the help of glacial isostatic adjustment modelling.

  16. Limitations of ozone data assimilation with adjustment of NOx emissions: mixed effects on NO2 forecasts over Beijing and surrounding areas

    NASA Astrophysics Data System (ADS)

    Tang, Xiao; Zhu, Jiang; Wang, ZiFa; Gbaguidi, Alex; Lin, CaiYan; Xin, JinYuan; Song, Tao; Hu, Bo

    2016-05-01

    This study investigates a cross-variable ozone data assimilation (DA) method based on an ensemble Kalman filter (EnKF) that has been used in the companion study to improve ozone forecasts over Beijing and surrounding areas. The main purpose is to delve into the impacts of the cross-variable adjustment of nitrogen oxide (NOx) emissions on the nitrogen dioxide (NO2) forecasts over this region during the 2008 Beijing Olympic Games. A mixed effect on the NO2 forecasts was observed through application of the cross-variable assimilation approach in the real-data assimilation (RDA) experiments. The method improved the NO2 forecasts over almost half of the urban sites with reductions of the root mean square errors (RMSEs) by 15-36 % in contrast to big increases of the RMSEs over other urban stations by 56-239 %. Over the urban stations with negative DA impacts, improvement of the NO2 forecasts (with 7 % reduction of the RMSEs) was noticed at night and in the morning versus significant deterioration during daytime (with 190 % increase of the RMSEs), suggesting that the negative data assimilation impacts mainly occurred during daytime. Ideal-data assimilation (IDA) experiments with a box model and the same cross-variable assimilation method confirmed the mixed effects found in the RDA experiments. In the same way, NOx emission estimation was improved at night and in the morning even under large biases in the prior emission, while it deteriorated during daytime (except for the case of minor errors in the prior emission). The mixed effects observed in the cross-variable data assimilation, i.e., positive data assimilation impacts on NO2 forecasts over some urban sites, negative data assimilation impacts over the other urban sites, and weak data assimilation impacts over suburban sites, highlighted the limitations of the EnKF under strong nonlinear relationships between chemical variables. Under strong nonlinearity between daytime ozone concentrations and NOx emissions

  17. Evaluating lidar point densities for effective estimation of aboveground biomass

    USGS Publications Warehouse

    Wu, Zhuoting; Dye, Dennis G.; Stoker, Jason; Vogel, John M.; Velasco, Miguel G.; Middleton, Barry R.

    2016-01-01

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) was recently established to provide airborne lidar data coverage on a national scale. As part of a broader research effort of the USGS to develop an effective remote sensing-based methodology for the creation of an operational biomass Essential Climate Variable (Biomass ECV) data product, we evaluated the performance of airborne lidar data at various pulse densities against Landsat 8 satellite imagery in estimating above ground biomass for forests and woodlands in a study area in east-central Arizona, U.S. High point density airborne lidar data, were randomly sampled to produce five lidar datasets with reduced densities ranging from 0.5 to 8 point(s)/m2, corresponding to the point density range of 3DEP to provide national lidar coverage over time. Lidar-derived aboveground biomass estimate errors showed an overall decreasing trend as lidar point density increased from 0.5 to 8 points/m2. Landsat 8-based aboveground biomass estimates produced errors larger than the lowest lidar point density of 0.5 point/m2, and therefore Landsat 8 observations alone were ineffective relative to airborne lidar for generating a Biomass ECV product, at least for the forest and woodland vegetation types of the Southwestern U.S. While a national Biomass ECV product with optimal accuracy could potentially be achieved with 3DEP data at 8 points/m2, our results indicate that even lower density lidar data could be sufficient to provide a national Biomass ECV product with accuracies significantly higher than that from Landsat observations alone.

  18. The effect of polygamous marital structure on behavioral, emotional, and academic adjustment in children: a comprehensive review of the literature.

    PubMed

    Elbedour, Salman; Onwuegbuzie, Anthony J; Caridine, Corin; Abu-Saad, Hasan

    2002-12-01

    Polygamy represents expanded family structures that are based on marriages involving a husband with 2 or more wives. Interestingly, polygamy is legally and widely practiced in 850 societies across the globe. In the last 2 decades, polygamy has been the focus of a significant growth in public, political, and academic awareness. Indeed, several quantitative and qualitative research articles and theoretical papers have emerged during this period, particularly concerning the effects of this form of marital structure on behavioral, emotional, and academic adjustment of children. However, to date, no researcher has provided a summary of the extant literature. Thus, the purpose of this comprehensive literature review is to summarize findings and to discuss implications of empirical studies that have examined whether polygamous marital structures are beneficial or harmful to children in comparison with children raised in monogamous marital structures. This review includes a summary of the findings from all quantitative and qualitative studies in the extant literature that have examined the effect of polygamy on children's outcomes.

  19. Unexperienced mechanical effects of muscular fatigue can be predicted by the Central Nervous System as revealed by anticipatory postural adjustments.

    PubMed

    Monjo, Florian; Forestier, Nicolas

    2014-09-01

    Muscular fatigue effects have been shown to be compensated by the implementation of adaptive compensatory neuromuscular strategies, resulting in modifications of the initial motion coordination. However, no studies have focused on the efficiency of the feedforward motor commands when muscular fatigue occurs for the first time during a particular movement. This study included 18 healthy subjects who had to perform arm-raising movements in a standing posture at a maximal velocity before and after a fatiguing procedure involving focal muscles. The arm-raising task implies the generation of predictive processes of control, namely Anticipatory Postural Adjustments (APAs), whose temporal and quantitative features have been shown to be dependent on the kinematics of the upcoming arm-raising movement. By altering significantly the kinematic profile of the focal movement with a fatiguing procedure, we sought to find out whether APAs scaled to the lower mechanical disturbance. APAs were measured using surface electromyography. Following the fatiguing procedure, acceleration peaks of the arm movement decreased by ~27%. APAs scaled to this lower fatigue-related disturbance during the very first trial post-fatigue, suggesting that the Central Nervous System can predict unexperienced mechanical effects of muscle fatigue. It is suggested that these results are accounted for by prediction processes in which the central integration of the groups III and IV afferents leads to an update of the internal model by remapping the relationship between focal motor command magnitude and the actual mechanical output.

  20. Sensitivity analyses for parametric causal mediation effect estimation.

    PubMed

    Albert, Jeffrey M; Wang, Wei

    2015-04-01

    Causal mediation analysis uses a potential outcomes framework to estimate the direct effect of an exposure on an outcome and its indirect effect through an intermediate variable (or mediator). Causal interpretations of these effects typically rely on sequential ignorability. Because this assumption is not empirically testable, it is important to conduct sensitivity analyses. Sensitivity analyses so far offered for this situation have either focused on the case where the outcome follows a linear model or involve nonparametric or semiparametric models. We propose alternative approaches that are suitable for responses following generalized linear models. The first approach uses a Gaussian copula model involving latent versions of the mediator and the final outcome. The second approach uses a so-called hybrid causal-observational model that extends the association model for the final outcome, providing a novel sensitivity parameter. These models, while still assuming a randomized exposure, allow for unobserved (as well as observed) mediator-outcome confounders that are not affected by exposure. The methods are applied to data from a study of the effect of mother education on dental caries in adolescence.

  1. Concurrent estimation of efficiency, effectiveness and returns to scale

    NASA Astrophysics Data System (ADS)

    Khodakarami, Mohsen; Shabani, Amir; Farzipoor Saen, Reza

    2016-04-01

    In recent years, data envelopment analysis (DEA) has been widely used to assess both efficiency and effectiveness. Accurate measurement of overall performance is a product of concurrent consideration of these measures. There are a couple of well-known methods to assess both efficiency and effectiveness. However, some issues can be found in previous methods. The issues include non-linearity problem, paradoxical improvement solutions, efficiency and effectiveness evaluation in two independent environments: dividing an operating unit into two autonomous departments for performance evaluation and problems associated with determining economies of scale. To overcome these issues, this paper aims to develop a series of linear DEA methods to estimate efficiency, effectiveness, and returns to scale of decision-making units (DMUs), simultaneously. This paper considers the departments of a DMU as a united entity to recommend consistent improvements. We first present a model under constant returns to scale (CRS) assumption, and examine its relationship with one of existing network DEA model. We then extend model under variable returns to scale (VRS) condition, and again its relationship with one of existing network DEA models is discussed. Next, we introduce a new integrated two-stage additive model. Finally, an in-depth analysis of returns to scale is provided. A case study demonstrates applicability of the proposed models.

  2. The effect of high leverage points on the maximum estimated likelihood for separation in logistic regression

    NASA Astrophysics Data System (ADS)

    Ariffin, Syaiba Balqish; Midi, Habshah; Arasan, Jayanthi; Rana, Md Sohel

    2015-02-01

    This article is concerned with the performance of the maximum estimated likelihood estimator in the presence of separation in the space of the independent variables and high leverage points. The maximum likelihood estimator suffers from the problem of non overlap cases in the covariates where the regression coefficients are not identifiable and the maximum likelihood estimator does not exist. Consequently, iteration scheme fails to converge and gives faulty results. To remedy this problem, the maximum estimated likelihood estimator is put forward. It is evident that the maximum estimated likelihood estimator is resistant against separation and the estimates always exist. The effect of high leverage points are then investigated on the performance of maximum estimated likelihood estimator through real data sets and Monte Carlo simulation study. The findings signify that the maximum estimated likelihood estimator fails to provide better parameter estimates in the presence of both separation, and high leverage points.

  3. Apollo Video Photogrammetry Estimation Of Plume Impingement Effects

    NASA Technical Reports Server (NTRS)

    Immer, Christopher; Lane, John; Metzger, Philip T.; Clements, Sandra

    2008-01-01

    The Constellation Project's planned return to the moon requires numerous landings at the same site. Since the top few centimeters are loosely packed regolith, plume impingement from the Lander ejects the granular material at high velocities. Much work is needed to understand the physics of plume impingement during landing in order to protect hardware surrounding the landing sites. While mostly qualitative in nature, the Apollo Lunar Module landing videos can provide a wealth of quantitative information using modem photogrammetry techniques. The authors have used the digitized videos to quantify plume impingement effects of the landing exhaust on the lunar surface. The dust ejection angle from the plume is estimated at 1-3 degrees. The lofted particle density is estimated at 10(exp 8)- 10(exp 13) particles per cubic meter. Additionally, evidence for ejection of large 10-15 cm sized objects and a dependence of ejection angle on thrust are presented. Further work is ongoing to continue quantitative analysis of the landing videos.

  4. Estimating Effects of Multipath Propagation on GPS Signals

    NASA Technical Reports Server (NTRS)

    Byun, Sung; Hajj, George; Young, Lawrence

    2005-01-01

    Multipath Simulator Taking into Account Reflection and Diffraction (MUSTARD) is a computer program that simulates effects of multipath propagation on received Global Positioning System (GPS) signals. MUSTARD is a very efficient means of estimating multipath-induced position and phase errors as functions of time, given the positions and orientations of GPS satellites, the GPS receiver, and any structures near the receiver as functions of time. MUSTARD traces each signal from a GPS satellite to the receiver, accounting for all possible paths the signal can take, including all paths that include reflection and/or diffraction from surfaces of structures near the receiver and on the satellite. Reflection and diffraction are modeled by use of the geometrical theory of diffraction. The multipath signals are added to the direct signal after accounting for the gain of the receiving antenna. Then, in a simulation of a delay-lock tracking loop in the receiver, the multipath-induced range and phase errors as measured by the receiver are estimated. All of these computations are performed for both right circular polarization and left circular polarization of both the L1 (1.57542-GHz) and L2 (1.2276-GHz) GPS signals.

  5. Estimating a marriage matching model with spillover effects.

    PubMed

    Choo, Eugene; Siow, Aloysius

    2006-08-01

    We use marriage matching functions to study how marital patterns change when population supplies change. Specifically, we use a behavioral marriage matching function with spillover effects to rationalize marriage and cohabitation behavior in contemporary Canada. The model can estimate a couple's systematic gains to marriage and cohabitation relative to remaining single. These gains are invariant to changes in population supplies. Instead, changes in population supplies redistribute these gains between a couple. Although the model is behavioral, it is nonparametric. It can fit any observed cross-sectional marriage matching distribution. We use the estimated model to quantify the impacts of gender differences in mortality rates and the baby boom on observed marital behavior in Canada. The higher mortality rate of men makes men scarcer than women. We show that the scarceness of men modestly reduced the welfare of women and increased the welfare of men in the marriage market. On the other hand, the baby boom increased older men's net gains to entering the marriage market and lowered middle-aged women's net gains.

  6. Effects of sampling standardization on estimates of Phanerozoic marine diversification

    PubMed Central

    Alroy, J.; Marshall, C. R.; Bambach, R. K.; Bezusko, K.; Foote, M.; Fürsich, F. T.; Hansen, T. A.; Holland, S. M.; Ivany, L. C.; Jablonski, D.; Jacobs, D. K.; Jones, D. C.; Kosnik, M. A.; Lidgard, S.; Low, S.; Miller, A. I.; Novack-Gottshall, P. M.; Olszewski, T. D.; Patzkowsky, M. E.; Raup, D. M.; Roy, K.; Sepkoski, J. J.; Sommers, M. G.; Wagner, P. J.; Webber, A.

    2001-01-01

    Global diversity curves reflect more than just the number of taxa that have existed through time: they also mirror variation in the nature of the fossil record and the way the record is reported. These sampling effects are best quantified by assembling and analyzing large numbers of locality-specific biotic inventories. Here, we introduce a new database of this kind for the Phanerozoic fossil record of marine invertebrates. We apply four substantially distinct analytical methods that estimate taxonomic diversity by quantifying and correcting for variation through time in the number and nature of inventories. Variation introduced by the use of two dramatically different counting protocols also is explored. We present sampling-standardized diversity estimates for two long intervals that sum to 300 Myr (Middle Ordovician-Carboniferous; Late Jurassic-Paleogene). Our new curves differ considerably from traditional, synoptic curves. For example, some of them imply unexpectedly low late Cretaceous and early Tertiary diversity levels. However, such factors as the current emphasis in the database on North America and Europe still obscure our view of the global history of marine biodiversity. These limitations will be addressed as the database and methods are refined. PMID:11353852

  7. 3D viscosity maps for Greenland and effect on GRACE mass balance estimates

    NASA Astrophysics Data System (ADS)

    van der Wal, Wouter; Xu, Zheng

    2016-04-01

    The GRACE satellite mission measures mass loss of the Greenland ice sheet. To correct for glacial isostatic adjustment numerical models are used. Although generally found to be a small signal, the full range of possible GIA models has not been explored yet. In particular, low viscosities due to a wet mantle and high temperatures due to the nearby Iceland hotspot could have a significant effect on GIA gravity rates. The goal of this study is to present a range of possible viscosity maps, and investigate the effect on GRACE mass balance estimates. Viscosity is derived using flow laws for olivine. Mantle temperature is computed from global seismology models, based on temperature derivatives for different mantle compositions. An indication for grain sizes is obtained by xenolith findings at a few locations. We also investigate the weakening effect of the presence of melt. To calculate gravity rates, we use a finite-element GIA model with the 3D viscosity maps and the ICE-5G loading history. GRACE mass balances for mascons in Greenland are derived with a least-squares inversion, using separate constraints for the inland and coastal areas in Greenland. Biases in the least-squares inversion are corrected using scale factors estimated from a simulation based on a surface mass balance model (Xu et al., submitted to The Cryosphere). Model results show enhanced gravity rates in the west and south of Greenland with 3D viscosity maps, compared to GIA models with 1D viscosity. The effect on regional mass balance is up to 5 Gt/year. Regional low viscosity can make present-day gravity rates sensitivity to ice thickness changes in the last decades. Therefore, an improved ice loading history for these time scales is needed.

  8. Time-adjusted variable resistor

    NASA Technical Reports Server (NTRS)

    Heyser, R. C.

    1972-01-01

    Timing mechanism was developed effecting extremely precisioned highly resistant fixed resistor. Switches shunt all or portion of resistor; effective resistance is varied over time interval by adjusting switch closure rate.

  9. Estimating effects of improved drinking water and sanitation on cholera.

    PubMed

    Leidner, Andrew J; Adusumilli, Naveen C

    2013-12-01

    Demand for adequate provision of drinking-water and sanitation facilities to promote public health and economic growth is increasing in the rapidly urbanizing countries of the developing world. With a panel of data on Asia and Africa from 1990 to 2008, associations are estimated between the occurrence of cholera outbreaks, the case rates in given outbreaks, the mortality rates associated with cholera and two disease control mechanisms, drinking-water and sanitation services. A statistically significant and negative effect is found between drinking-water services and both cholera case rates as well as cholera-related mortality rates. A relatively weak statistical relationship is found between the occurrence of cholera outbreaks and sanitation services.

  10. Systemic estimation of the effect of photodynamic therapy of cancer

    NASA Astrophysics Data System (ADS)

    Kogan, Eugenia A.; Meerovich, Gennadii A.; Torshina, Nadezgda L.; Loschenov, Victor B.; Volkova, Anna I.; Posypanova, Anna M.

    1997-12-01

    The effects of photodynamic therapy (PDT) of cancer needs objective estimation and its unification in experimental as well as in clinical studies. They must include not only macroscopical changes but also the complex of following morphological criteria: (1) the level of direct tumor damage (direct necrosis and apoptosis); (2) the level of indirect tumor damage (ischemic necrosis); (3) the signs of vascular alterations; (4) the local and systemic antiblastome resistance; (5) the proliferative activity and malignant potential of survival tumor tissue. We have performed different regimes PDT using phthalocyanine derivatives. The complex of morphological methods (Ki-67, p53, c-myc, bcl-2) was used. Obtained results showed the connection of the tilted morphological criteria with tumor regression.

  11. Apollo Video Photogrammetry Estimation of Plume Impingement Effects

    NASA Technical Reports Server (NTRS)

    Immer, Christopher; Lane, John; Metzger, Philip; Clements, Sandra

    2008-01-01

    Each of the six Apollo mission landers touched down at unique sites on the lunar surface. Aside from the Apollo 12 landing site located 180 meters from the Surveyor III lander, plume impingement effects on ground hardware during the landings were largely not an issue. The Constellation Project's planned return to the moon requires numerous landings at the same site. Since the top few centimeters are loosely packed regolith, plume impingement from the lander ejects the granular material at high velocities. With high vacuum conditions on the moon (10 (exp -14) to 10 (epx -12) torr), motion of all particles is completely ballistic. Estimates from damage to the Surveyor III show that the ejected regolith particles to be anywhere 400 m/s to 2500 m/s. It is imperative to understand the physics of plume impingement to safely design landing sites for the Constellation Program.

  12. Estimation of capture probabilities using generalized estimating equations and mixed effects approaches

    PubMed Central

    Akanda, Md Abdus Salam; Alpizar-Jara, Russell

    2014-01-01

    Modeling individual heterogeneity in capture probabilities has been one of the most challenging tasks in capture–recapture studies. Heterogeneity in capture probabilities can be modeled as a function of individual covariates, but correlation structure among capture occasions should be taking into account. A proposed generalized estimating equations (GEE) and generalized linear mixed modeling (GLMM) approaches can be used to estimate capture probabilities and population size for capture–recapture closed population models. An example is used for an illustrative application and for comparison with currently used methodology. A simulation study is also conducted to show the performance of the estimation procedures. Our simulation results show that the proposed quasi-likelihood based on GEE approach provides lower SE than partial likelihood based on either generalized linear models (GLM) or GLMM approaches for estimating population size in a closed capture–recapture experiment. Estimator performance is good if a large proportion of individuals are captured. For cases where only a small proportion of individuals are captured, the estimates become unstable, but the GEE approach outperforms the other methods. PMID:24772290

  13. Aging Effects on Behavioural Estimates of Suppression with Short Suppressors.

    PubMed

    Hegland, Erica L; Strickland, Elizabeth A

    2016-01-01

    Auditory two-tone suppression is a nearly instantaneous reduction in the response of the basilar membrane to a tone or noise when a second tone or noise is presented simultaneously. Previous behavioural studies provide conflicting evidence on whether suppression changes with increasing age, and aging effects may depend on whether a suppressor above (high-side) or below (low-side) the signal frequency is used. Most previous studies have measured suppression using stimuli long enough to elicit the medial olivocochlear reflex (MOCR), a sound-elicited reflex that reduces cochlear amplification or gain. It has a "sluggish" onset of approximately 25 ms. There is physiological evidence that suppression may be reduced or altered by elicitation of the MOCR. In the present study, suppression was measured behaviourally in younger adults and older adults using a forward-masking paradigm with 20-ms and 70-ms maskers and suppressors. In experiment 1, gain was estimated by comparing on-frequency (2 kHz) and off-frequency (1.2 kHz) masker thresholds for a short, fixed-level 2-kHz signal. In experiment 2, the fixed-level signal was preceded by an off-frequency suppressor (1.2 or 2.4 kHz) presented simultaneously with the on-frequency masker. A suppressor level was chosen that did not produce any forward masking of the signal. Suppression was measured as the difference in on-frequency masker threshold with and without the suppressor present. The effects of age on gain and suppression estimates will be discussed.

  14. Tools and techniques for estimating high intensity RF effects

    SciTech Connect

    Zacharias, R.; Pennock, S.; Poggio, A.; Ray, S.

    1991-07-01

    With the ever-increasing dependence of modern aircraft on sophisticated avionics and electronic controls, the need to assure aircraft survivatality when exposed to high Intensity RF (HIRF) signals has become of great Interest. Advisory regulation is currently being proposed which would require testing and/or analysis to assure RF hardness of installed flight critical and flight essential equipment. While full-aircraft, full-threat testing may be the most thorough manner to assure survivability, it is not generally practical in loins of cost. Various combinations of limited full-aircraft testing, box-level testing, modeling, and analysis are also being considered as methods to achieve compliance. Modeling, analysis, and low power measurements may hold the key to making full-system survivability estimates at reasonable cost. In this paper we will describe some of the tools and techniques we use for estimating and measuring coupling and component disturbance. A finite difference time domain modeling code, TSAR, used to predict coupling will be described. This code has the capability to quickly generate a mesh model to represent the test object. Some recent applications as well as the advantages and limitations of using such a code will be described. We will also describe some of the facilities and techniques we have developed for making low power coupling measurements and for making direct injection test measurements of device disturbance. Some scaling laws for coupling and device effects will be presented. A method to extrapolate these low-power test results to high-power full-system effects will be presented.

  15. 48 CFR 552.243-71 - Equitable Adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... operation to be performed; (4) Cost of preparation and/or revision to shop drawings and other submittals... adjustment warrants estimating, scheduling, or other effort not reasonably foreseeable at the time of... part 31 of the Federal Acquisition Regulation (48 CFR part 31) in effect on the date of this...

  16. Biochar's effect on soil nitrous oxide emissions from a maize field with lime adjusted pH treatment

    NASA Astrophysics Data System (ADS)

    Hüppi, Roman; Leifeld, Jens; Felber, Raphael; Neftel, Albrecht; Six, Johan

    2015-04-01

    Biochar is a carbon-rich, porous product from pyrolysis of organic residues. Especially tropical soils have shown positive response in yield to biochar addition. Its high stability in soil makes biochar a potent carbon sequestration option at the same time. A number of laboratory incubations have shown significantly reduced nitrous oxide (N2O) emissions from soil when mixed with biochar. Emission measurements from the field show the same trend but are much more scarce. One of the hypothesized mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH from the application of alkaline biochar. To test the effect of biochar on N2O emissions from a temperate maize system, we set up a field trial with a 20 t/ha biochar treatment, a limestone treatment adjusted to the same pH as with biochar and a control without addition. An automated static chamber greenhouse gas measurement system measured N2O emissions for each replicated (n=3) every 3.6 hours. The field was conventionally fertilised at a rate of 160 kg-N/ha in 3 doses of 40, 80 and 40 kg-N/ha. Cumulative emissions show a significant reduction for N2O in the biochar treatment by about 55 % relative to the control. The limed treatment shows similar emissions than control but with higher variability. This suggests that the N2O reduction effect of biochar is not mainly due to its liming effect. In conclusion, we confirm that biochar is a promising material to reduce N2O emissions from intensively managed agricultural soils.

  17. Parents who hit and scream: interactive effects of verbal and severe physical aggression on clinic-referred adolescents' adjustment.

    PubMed

    LeRoy, Michelle; Mahoney, Annette; Boxer, Paul; Gullan, Rebecca Lakin; Fang, Qijuan

    2014-05-01

    The goals of this study were first, to delineate the co-occurrence of parental severe physical aggression and verbal aggression toward clinic-referred adolescents, and second, to examine the interactive effects of parental severe physical aggression and verbal aggression on adolescent externalizing and internalizing behavior problems. This research involved 239 referrals of 11- to 18-year-old youth and their dual-parent families to a non-profit, private community mental health center in a semi-rural Midwest community. Multiple informants (i.e., adolescents and mothers) were used to assess parental aggression and adolescent behavior problems. More than half of clinic-referred adolescents (51%) experienced severe physical aggression and/or high verbal aggression from one or both parents. A pattern of interactive effects of mother-to-adolescent severe physical aggression and verbal aggression on adolescent behavior problems emerged, indicating that when severe physical aggression was present, mother-to-adolescent verbal aggression was positively associated with greater adolescent behavior problems whereas when severe physical aggression was not present, the links between verbal aggression and behavior problems was no longer significant. No interactive effects were found for father-to-adolescent severe physical aggression and verbal aggression on adolescent adjustment; however, higher father-to-adolescent verbal aggression was consistently linked to behavior problems above and beyond the influence of severe physical aggression. The results of this study should promote the practice of routinely assessing clinic-referred adolescents and their parents about their experiences of verbal aggression in addition to severe physical aggression and other forms of abuse.

  18. Spousal Adjustment to Myocardial Infarction.

    ERIC Educational Resources Information Center

    Ziglar, Elisa J.

    This paper reviews the literature on the stresses and coping strategies of spouses of patients with myocardial infarction (MI). It attempts to identify specific problem areas of adjustment for the spouse and to explore the effects of spousal adjustment on patient recovery. Chapter one provides an overview of the importance in examining the…

  19. Signal Amplification in Field Effect-Based Sandwich Enzyme-Linked Immunosensing by Tuned Buffer Concentration with Ionic Strength Adjuster.

    PubMed

    Kumar, Satyendra; Kumar, Narendra; Panda, Siddhartha

    2016-04-01

    Miniaturization of the sandwich enzyme-based immunosensor has several advantages but could result in lower signal strength due to lower enzyme loading. Hence, technologies for amplification of the signal are needed. Signal amplification in a field effect-based electrochemical immunosensor utilizing chip-based ELISA is presented in this work. First, the molarities of phosphate buffer saline (PBS) and concentrations of KCl as ionic strength adjuster were optimized to maximize the GOx glucose-based enzymatic reactions in a beaker for signal amplification measured by change in the voltage shift with an EIS device (using 20 μl of solution) and validated with a commercial pH meter (using 3 ml of solution). The PBS molarity of 100 μM with 25 mM KCl provided the maximum voltage shift. These optimized buffer conditions were further verified for GOx immobilized on silicon chips, and similar trends with decreased PBS molarity were obtained; however, the voltage shift values obtained on chip reaction were lower as compared to the reactions occurring in the beaker. The decreased voltage shift with immobilized enzyme on chip could be attributed to the increased Km (Michaelis-Menten constant) values in the immobilized GOx. Finally, a more than sixfold signal enhancement (from 8 to 47 mV) for the chip-based sandwich immunoassay was obtained by altering the PBS molarity from 10 to 100 μM with 25 mM KCl.

  20. Disability-adjusted life years in the assessment of health effects of traffic-related air pollution.

    PubMed

    Adamkiewicz, Ł; Badyda, A J; Gayer, A; Mucha, D

    2015-01-01

    Traffic-related air pollutants have an impact on human health and have been recognized as one of the main stressors that cause mortality and morbidity in urban areas. Research confirms that citizens living in the vicinity of main roads are strongly exposed to high concentrations of numerous air pollutants. In the present study the measurements of traffic-related parameters such as density, velocity, and structure were performed for cross-sections of selected street canyons in Warsaw, the capital city of Poland. In addition, the results of the general traffic measurements were used to describe the number of cars crossing the border of the city. Vehicle emissions of PM10 were calculated for the whole city area and changes of the PM10 concentration were modeled to present the exposure to this pollutant that could be attributable to traffic. The principles of the environmental burden of disease (EBD) were used. The assessment of the impact of traffic-related air pollutants on human health was made. The results, presented in disability-adjusted life years (DALY), were based on the outcomes of the study conducted in 2008-2012 in Warsaw, one the most congested agglomerations in Europe, and included the health damage effect of the exposure to high concentrations of air pollutants. DALY calculations were performed in accordance to the methodologies used in renowned international scientific research on EBD.

  1. A highly effective and adjustable dual plasmid system for O-GlcNAcylated recombinant protein production in E. coli.

    PubMed

    Han, Cuifang; Shan, Hui; Bi, Chuanlin; Zhang, Xinling; Qi, Jieqiong; Zhang, Boyuan; Gu, Yuchao; Yu, Wengong

    2015-06-01

    O-GlcNAcylation is a ubiquitous, dynamic and reversible post-translational protein modification in metazoans, and it is catalysed and removed by O-GlcNAc transferase (OGT) and O-GlcNAcase, respectively. Prokaryotes lack endogenous OGT activity. It has been reported that coexpression of mammalian OGT with its target substrates in Escherichia coli produce O-GlcNAcylated recombinant proteins, but the plasmids used were not compatible, and the expression of both OGT and its target protein were induced by the same inducer. Here, we describe a compatible dual plasmid system for coexpression of OGT and its target substrate for O-GlcNAcylated protein production in E. coli. The approach was validated using the CKII and p53 protein as control. This compatible dual plasmid system contains an arabinose-inducible OGT expression vector with a pUC origin and an isopropyl β-d-thiogalactopyranoside-inducible OGT target substrate expression vector bearing a p15A origin. The dual plasmid system produces recombinant proteins with varying O-GlcNAcylation levels by altering the inducer concentration. More importantly, the O-GlcNAcylation efficiency was much higher than the previously reported system. Altogether, we established an adjustable compatible dual plasmid system that can effectively yield O-GlcNAcylated proteins in E. coli.

  2. Clinical effectiveness of the activator adjusting instrument in the management of musculoskeletal disorders: a systematic review of the literature

    PubMed Central

    Huggins, Tiffany; Boras, Ana Luburic; Gleberzon, Brian J.; Popescu, Mara; Bahry, Lianna A.

    2012-01-01

    Objective: The purpose of this study was to conduct a systematic review of the literature investigating clinical outcomes involving the use of the Activator Adjusting Instrument (AAI) or Activator Methods Chiropractic Technique (AMCT). Methods: A literature synthesis was performed on the available research and electronic databases, along with hand-searching of journals and reference tracking for any studies that investigated the AAI in terms of clinical effectiveness. Studies that met the inclusion criteria were evaluated using an instrument that assessed their methodological quality. Results: Eight articles met the inclusion criteria. Overall, the AAI provided comparable clinically meaningful benefits to patients when compared to high-velocity, low-amplitude (HVLA) manual manipulation or trigger point therapy for patients with acute and chronic spinal pain, temporomandibular joint (TMJ) dysfunction and trigger points of the trapezius muscles. Conclusion: This systematic review of 8 clinical trials involving the use of the AAI found reported benefits to patients with a spinal pain and trigger points, although the clinical trials reviewed suffered from many methodological limitations, including small sample size, relatively brief follow-up period and lack of control or sham treatment groups. PMID:22457541

  3. Small-area health comparisons using health-adjusted life expectancies: a Bayesian random-effects approach.

    PubMed

    Jonker, Marcel F; Congdon, Peter D; van Lenthe, Frank J; Donkers, Bas; Burdorf, Alex; Mackenbach, Johan P

    2013-09-01

    Health-adjusted life expectancy (HALE) is one of the most attractive summary measures of population health. It provides balanced attention to fatal as well as non-fatal health outcomes, is sensitive to the severity of morbidity within the population, and can be readily compared between areas with very different population age structures. HALE, however, cannot be calculated at the small-area level using traditional life table methodology. Hence we propose a Bayesian random-effects modeling approach that recognizes correlations and pools strength between sexes, age-groups, geographical areas, and health outcomes. This approach allows for the calculation of HALE for areas as small as 2000 person years at risk and with relatively modest health state survey sample sizes. The feasibility of the Bayesian approach is illustrated in a real-life example, which also shows how differences in areas' health performances can be adequately quantified. Such information can be invaluable for the appropriate targetting and subsequent evaluation of urban regeneration, neighborhood renewal, and community-based initiatives aimed at improving health and reducing health inequalities. PMID:23778148

  4. Food portion estimation by children with obesity: the effects of estimation method and food type.

    PubMed

    Friedman, Alinda; Bennett, Tesia G; Barbarich, Bobbi N; Keaschuk, Rachel A; Ball, Geoff D C

    2012-02-01

    Several factors influence children's ability to report accurate information about their dietary intake. To date, one understudied area of dietary assessment research relates to children's ability to estimate portion sizes of food. The purpose of this cross-sectional research was to examine food portion size estimation accuracy in 7- to 18-year-old children with obesity. Two within-subject experiments (Experiment 1: n=28, Experiment 2: n=27) were conducted in Edmonton, Alberta, Canada, during 2007-2008. Three types of portion size measurement aids (PSMAs) (eg, measuring cups and spoons, household objects [full and half-sized], and modeling clay) were counterbalanced in a Latin Square design for participants to estimate four types of foods (ie, solid, liquid, amorphous pieces, and amorphous masses). Analyses of variance conducted on percent of signed and absolute errors yielded significant PSMA type×food type interactions (P<0.01) in both experiments. Across all food types, for Experiments 1 and 2, measuring cups and spoons produced the least accurate estimates with respect to absolute error (54.2% and 53.1%, respectively), whereas modeling clay produced the most accurate estimates (40.6% and 33.2%, respectively). Half sizes of household objects also yielded enhanced accuracy (47.9% to 37.2%). Finally, there were significant differences in accuracy between amorphous pieces (eg, grapes) vs amorphous masses (eg, mashed potatoes; P<0.01), indicating that there are qualitative differences in how different amorphous foods are estimated. These data are relevant when collecting food intake data from children with obesity and indicate that different PSMAs may be needed to optimize food portion size estimation accuracy for different food types. PMID:22732463

  5. FMRI group analysis combining effect estimates and their variances

    PubMed Central

    Chen, Gang; Saad, Ziad S.; Nath, Audrey R.; Beauchamp, Michael S.; Cox, Robert W.

    2012-01-01

    Conventional functional magnetic resonance imaging (FMRI) group analysis makes two key assumptions that are not always justified. First, the data from each subject is condensed into a single number per voxel, under the assumption that within-subject variance for the effect of interest is the same across all subjects or is negligible relative to the cross-subject variance. Second, it is assumed that all data values are drawn from the same Gaussian distribution with no outliers. We propose an approach that does not make such strong assumptions, and present a computationally efficient frequentist approach to FMRI group analysis, which we term mixed-effects multilevel analysis (MEMA), that incorporates both the variability across subjects and the precision estimate of each effect of interest from individual subject analyses. On average, the more accurate tests result in higher statistical power, especially when conventional variance assumptions do not hold, or in the presence of outliers. In addition, various heterogeneity measures are available with MEMA that may assist the investigator in further improving the modeling. Our method allows group effect t-tests and comparisons among conditions and among groups. In addition, it has the capability to incorporate subject-specific covariates such as age, IQ, or behavioral data. Simulations were performed to illustrate power comparisons and the capability of controlling type I errors among various significance testing methods, and the results indicated that the testing statistic we adopted struck a good balance between power gain and type I error control. Our approach is instantiated in an open-source, freely distributed program that may be used on any dataset stored in the universal neuroimaging file transfer (NIfTI) format. To date, the main impediment for more accurate testing that incorporates both within- and cross-subject variability has been the high computational cost. Our efficient implementation makes this approach

  6. Estimating anatomical trajectories with Bayesian mixed-effects modeling

    PubMed Central

    Ziegler, G.; Penny, W.D.; Ridgway, G.R.; Ourselin, S.; Friston, K.J.

    2015-01-01

    We introduce a mass-univariate framework for the analysis of whole-brain structural trajectories using longitudinal Voxel-Based Morphometry data and Bayesian inference. Our approach to developmental and aging longitudinal studies characterizes heterogeneous structural growth/decline between and within groups. In particular, we propose a probabilistic generative model that parameterizes individual and ensemble average changes in brain structure using linear mixed-effects models of age and subject-specific covariates. Model inversion uses Expectation Maximization (EM), while voxelwise (empirical) priors on the size of individual differences are estimated from the data. Bayesian inference on individual and group trajectories is realized using Posterior Probability Maps (PPM). In addition to parameter inference, the framework affords comparisons of models with varying combinations of model order for fixed and random effects using model evidence. We validate the model in simulations and real MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project. We further demonstrate how subject specific characteristics contribute to individual differences in longitudinal volume changes in healthy subjects, Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD). PMID:26190405

  7. Estimating anatomical trajectories with Bayesian mixed-effects modeling.

    PubMed

    Ziegler, G; Penny, W D; Ridgway, G R; Ourselin, S; Friston, K J

    2015-11-01

    We introduce a mass-univariate framework for the analysis of whole-brain structural trajectories using longitudinal Voxel-Based Morphometry data and Bayesian inference. Our approach to developmental and aging longitudinal studies characterizes heterogeneous structural growth/decline between and within groups. In particular, we propose a probabilistic generative model that parameterizes individual and ensemble average changes in brain structure using linear mixed-effects models of age and subject-specific covariates. Model inversion uses Expectation Maximization (EM), while voxelwise (empirical) priors on the size of individual differences are estimated from the data. Bayesian inference on individual and group trajectories is realized using Posterior Probability Maps (PPM). In addition to parameter inference, the framework affords comparisons of models with varying combinations of model order for fixed and random effects using model evidence. We validate the model in simulations and real MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project. We further demonstrate how subject specific characteristics contribute to individual differences in longitudinal volume changes in healthy subjects, Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD).

  8. Estimating anatomical trajectories with Bayesian mixed-effects modeling.

    PubMed

    Ziegler, G; Penny, W D; Ridgway, G R; Ourselin, S; Friston, K J

    2015-11-01

    We introduce a mass-univariate framework for the analysis of whole-brain structural trajectories using longitudinal Voxel-Based Morphometry data and Bayesian inference. Our approach to developmental and aging longitudinal studies characterizes heterogeneous structural growth/decline between and within groups. In particular, we propose a probabilistic generative model that parameterizes individual and ensemble average changes in brain structure using linear mixed-effects models of age and subject-specific covariates. Model inversion uses Expectation Maximization (EM), while voxelwise (empirical) priors on the size of individual differences are estimated from the data. Bayesian inference on individual and group trajectories is realized using Posterior Probability Maps (PPM). In addition to parameter inference, the framework affords comparisons of models with varying combinations of model order for fixed and random effects using model evidence. We validate the model in simulations and real MRI data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) project. We further demonstrate how subject specific characteristics contribute to individual differences in longitudinal volume changes in healthy subjects, Mild Cognitive Impairment (MCI), and Alzheimer's Disease (AD). PMID:26190405

  9. Effects on pulmonary health of neighboring residents of concentrated animal feeding operations: exposure assessed using optimized estimation technique.

    PubMed

    Schulze, Anja; Römmelt, Horst; Ehrenstein, Vera; van Strien, Rob; Praml, Georg; Küchenhoff, Helmut; Nowak, Dennis; Radon, Katja

    2011-01-01

    Potential adverse health effects of concentrated animal feeding operations (CAFOs), which were also shown in the authors' Lower Saxony Lung Study, are of public concern. The authors aimed to investigate pulmonary health effect of neighboring residents assessed using optimized estimation technique. Annual ammonia emission was measured to assess the emission from CAFO and from surrounding fields. Location of sampling points was optimized using cluster analysis. Individual exposure of 457 nonfarm subjects was interpolated by weighting method. Mean estimated annual ammonia levels varied between 16 and 24 μg/m³. Higher exposed participants were more likely to be sensitized against ubiquitous allergens as compared to lower exposed subjects (adjusted odds ratio [OR] 4.2; 95% confidence interval [CI] 1.2-13.2). In addition, they showed a significantly lower forced expiratory volume in 1 second (FEV₁) (adjusted mean difference in % of predicted -8%; 95% CI -13% to -3%). The authors' previous findings that CAFOs may contribute to burden of respiratory diseases were confirmed by this study. PMID:21864103

  10. Estimating the Effects of Detection Heterogeneity and Overdispersion on Trends Estimated from Avian Point Counts

    EPA Science Inventory

    Point counts are a common method for sampling avian distribution and abundance. Though methods for estimating detection probabilities are available, many analyses use raw counts and do not correct for detectability. We use a removal model of detection within an N-mixture approa...

  11. Proxies for site effect estimation: can statistics help us?

    NASA Astrophysics Data System (ADS)

    Cultrera, G.; Cadet, H.; De Rubeis, V.; Theodoulidis, N.; Bard, P.-Y.; Di Giulio, G.

    2012-04-01

    The earthquake site response is one of the causes of different damage level at nearby sites. Its assessment is possibly based on empirical methods using the earthquake recordings. However, when limited resources and/or recorded earthquakes are not available, several proxies are used. In this framework the standard spectral ratio (SSR) is considered the reference empirical method to detect amplification as a function of frequency, but other estimates can be easily obtained from noise measurements. The ambient noise is largely used to compute the Horizontal-to-Vertical Spectral Ratio (HVN) and the Rayleigh-wave dispersion curve (DC). The first method, HVN, realistically indicates the fundamental frequency but, for the majority of the worldwide-examined sites, its reliability in terms of amplitude is controversial. The dispersion curve, DC, instead, is inverted to obtain the shear-wave velocity profile below the station and to compute the average shear-wave velocity in the first 30 meters (Vs30); the Vs30 parameter is then used as a most common proxy of site effect, even though it is presently criticized because it cannot represent alone the main physics of site response. Using a well-known statistical tool, the canonical correlation analysis, we verify and quantify the relationship between HVN and SSR measured at the same sites, and between DC and SSR computed for another database. We studied the correlation between SSR and HVN using recordings from 64 sites worldwide and we show that linear combinations of the HVN amplitudes in different frequency intervals are significantly correlated to linear combinations of the SSR. These results can be used to estimate the expected SSR spectral ratio from the recorded HVN curve at sites located in the same investigated areas. The canonical correlation between SSR and DC has been studied on a set of theoretical dispersion curves and transfer functions, computed from shear-wave velocity (Vs) profiles measured at more than 400

  12. Adjustable Autonomy Testbed

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Schrenkenghost, Debra K.

    2001-01-01

    The Adjustable Autonomy Testbed (AAT) is a simulation-based testbed located in the Intelligent Systems Laboratory in the Automation, Robotics and Simulation Division at NASA Johnson Space Center. The purpose of the testbed is to support evaluation and validation of prototypes of adjustable autonomous agent software for control and fault management for complex systems. The AA T project has developed prototype adjustable autonomous agent software and human interfaces for cooperative fault management. This software builds on current autonomous agent technology by altering the architecture, components and interfaces for effective teamwork between autonomous systems and human experts. Autonomous agents include a planner, flexible executive, low level control and deductive model-based fault isolation. Adjustable autonomy is intended to increase the flexibility and effectiveness of fault management with an autonomous system. The test domain for this work is control of advanced life support systems for habitats for planetary exploration. The CONFIG hybrid discrete event simulation environment provides flexible and dynamically reconfigurable models of the behavior of components and fluids in the life support systems. Both discrete event and continuous (discrete time) simulation are supported, and flows and pressures are computed globally. This provides fast dynamic simulations of interacting hardware systems in closed loops that can be reconfigured during operations scenarios, producing complex cascading effects of operations and failures. Current object-oriented model libraries support modeling of fluid systems, and models have been developed of physico-chemical and biological subsystems for processing advanced life support gases. In FY01, water recovery system models will be developed.

  13. Effect of packing density on strain estimation by Fry method

    NASA Astrophysics Data System (ADS)

    Srivastava, Deepak; Ojha, Arun

    2015-04-01

    Fry method is a graphical technique that uses relative movement of material points, typically the grain centres or centroids, and yields the finite strain ellipse as the central vacancy of a point distribution. Application of the Fry method assumes an anticlustered and isotropic grain centre distribution in undistorted samples. This assumption is, however, difficult to test in practice. As an alternative, the sedimentological degree of sorting is routinely used as an approximation for the degree of clustering and anisotropy. The effect of the sorting on the Fry method has already been explored by earlier workers. This study tests the effect of the tightness of packing, the packing density%, which equals to the ratio% of the area occupied by all the grains and the total area of the sample. A practical advantage of using the degree of sorting or the packing density% is that these parameters, unlike the degree of clustering or anisotropy, do not vary during a constant volume homogeneous distortion. Using the computer graphics simulations and the programming, we approach the issue of packing density in four steps; (i) generation of several sets of random point distributions such that each set has same degree of sorting but differs from the other sets with respect to the packing density%, (ii) two-dimensional homogeneous distortion of each point set by various known strain ratios and orientation, (iii) estimation of strain in each distorted point set by the Fry method, and, (iv) error estimation by comparing the known strain and those given by the Fry method. Both the absolute errors and the relative root mean squared errors give consistent results. For a given degree of sorting, the Fry method gives better results in the samples having greater than 30% packing density. This is because the grain centre distributions show stronger clustering and a greater degree of anisotropy with the decrease in the packing density. As compared to the degree of sorting alone, a

  14. Estimation of dynamic treatment strategies for maintenance therapy of children with acute lymphoblastic leukaemia: an application of history-adjusted marginal structural models.

    PubMed

    Rosthøj, S; Keiding, N; Schmiegelow, K

    2012-02-28

    Childhood acute lymphoblastic leukaemia is treated with long-term intensive chemotherapy. During the latter part of the treatment, the maintenance therapy, the patients receive oral doses of two cytostatics. The doses are tailored to blood counts measured on a weekly basis, and the treatment is therefore highly dynamic. In 1992-1996, the Nordic Society of Paediatric Haematology and Oncology (NOPHO) conducted a randomised study (NOPHO-ALL-92) to investigate the effect of a new and more sophisticated dynamic treatment strategy. Unexpectedly, the new strategy worsened the outcome for the girls, whereas there were no treatment differences for the boys. There are as yet no general guidelines for optimising the treatment. On basis of the data from this study, our goal is to formulate an alternative dosing strategy. We use recently developed methods proposed by van der Laan et al. to obtain statistical models that may be used in the guidance of how the physicians should assign the doses to the patients to obtain the target of the treatment. We present a possible strategy and discuss the reliability of this strategy. The implementation is complicated, and we touch upon the limitations of the methods in relation to the formulation of alternative dosing strategies for the maintenance therapy.

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

    PubMed

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

    2016-05-01

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

  16. Language Adjustment of International Students in the US: A Social Network Analysis on the Effects of Language Resources, Language Norm and Technology

    ERIC Educational Resources Information Center

    Qiu, Wei

    2011-01-01

    The study explores factors that enhance or inhibit the language adjustment of international students in the U.S. Using social network influence model, the study examines the effects of language resources, language norm, and technology use on international students' self-confidence in overall English skills and four subskills, namely, listening,…

  17. The Effects of Economic and Social Stressors on Parenting and Adolescent Adjustment of African-American Families. CEIC Research Brief, No. 109.

    ERIC Educational Resources Information Center

    Taylor, Ronald

    This study examines economic and social stressors and their effects on the parenting styles and adolescent adjustment of African American families. It systematically characterizes and explains the nature of some of the chronic economic and social stressors experienced by poor African American families as they affect parenting and adolescent…

  18. Growing up in a Dangerous Developmental Milieu: The Effects of Parenting Processes on Adjustment in Inner-City African American Adolescents

    ERIC Educational Resources Information Center

    Vazsonyi, Alexander T.; Pickering, Lloyd E.; Bolland, John M.

    2006-01-01

    The current longitudinal study examined the protective effects of parenting processes on measures of adolescent adjustment (health-compromising and violent behaviors) in a sample of high-risk, inner-city, poor African American youth N = 2,867). Parenting processes played an important role in this dangerous developmental milieu. For male…

  19. Effectiveness of Group Positive Parenting Program (Triple P) in Changing Child Behavior, Parenting Style, and Parental Adjustment: An Intervention Study in Japan

    ERIC Educational Resources Information Center

    Fujiwara, Takeo; Kato, Noriko; Sanders, Matthew R.

    2011-01-01

    The purpose of this study is to investigate the effectiveness of a group-based family intervention program known as the Group Positive Parenting Program (Triple P), with families in Japan. Reductions in children's behavioral problems, changes in dysfunctional parenting practices, and affects on parenting adjustment were examined. Participants of…

  20. A Monte Carlo estimation of effective dose in chest tomosynthesis

    SciTech Connect

    Sabol, John M.

    2009-12-15

    calculated to be 0.124 mSv (ICRP60) [0.134 mSv (ICRP103)]. This is less than 75% of that predicted by scaling of the PA mA s ratio. This lower dose was due to changes in the focal-spot-to-skin distance, effective changes in collimation with projection angle, rounding down of the mA s step, and variations in organ exposure to the primary x-ray beam for each view. Large errors in dose estimation can occur if these factors are not accurately modeled. Conclusions: The effective dose of a chest examination with this chest tomosynthesis system is about twice that of a two-view chest examination and less than 2% of the published average values for thoracic CT. It is shown that complete consideration of the tomosynthesis acquisition technique and geometry is required for accurate determination of the effective dose to the patient. Tomosynthesis provides three-dimensional imaging at a dose level comparable to a two-view chest x-ray examination and may provide a low dose alternative to thoracic CT for obtaining depth information in chest imaging.

  1. Longitudinal field investigation of the moderating and mediating effects of self-efficacy on the relationship between training and newcomer adjustment.

    PubMed

    Saks, A M

    1995-04-01

    A longitudinal field study examined the moderating and mediating effects of self-efficacy on the relationship between training and the adjustment of newcomers during their 1st year of employment. The results provided some support for the hypothesis that initial self-efficacy moderates the relationship between training and adjustment. Training was more strongly related to posttraining self-efficacy, ability to cope, job performance, and intention to quit the profession for newcomers with low levels of initial self-efficacy mediates the relationship between training and adjustment; however, evidence of complete mediation was found only for ability to cope. Posttraining self-efficacy partially mediated the relationships between training and job satisfaction, organizational and professional commitment, and intention to quit the organization and the profession. Research and practical implications of these findings for the training and the socialization of newcomers are discussed.

  2. Effect of Random Clustering on Surface Damage Density Estimates

    SciTech Connect

    Matthews, M J; Feit, M D

    2007-10-29

    Identification and spatial registration of laser-induced damage relative to incident fluence profiles is often required to characterize the damage properties of laser optics near damage threshold. Of particular interest in inertial confinement laser systems are large aperture beam damage tests (>1cm{sup 2}) where the number of initiated damage sites for {phi}>14J/cm{sup 2} can approach 10{sup 5}-10{sup 6}, requiring automatic microscopy counting to locate and register individual damage sites. However, as was shown for the case of bacteria counting in biology decades ago, random overlapping or 'clumping' prevents accurate counting of Poisson-distributed objects at high densities, and must be accounted for if the underlying statistics are to be understood. In this work we analyze the effect of random clumping on damage initiation density estimates at fluences above damage threshold. The parameter {psi} = a{rho} = {rho}/{rho}{sub 0}, where a = 1/{rho}{sub 0} is the mean damage site area and {rho} is the mean number density, is used to characterize the onset of clumping, and approximations based on a simple model are used to derive an expression for clumped damage density vs. fluence and damage site size. The influence of the uncorrected {rho} vs. {phi} curve on damage initiation probability predictions is also discussed.

  3. The effect of band loss on estimates of annual survival

    USGS Publications Warehouse

    Nelson, Louis J.; Anderson, David R.; Burnham, Kenneth P.

    1980-01-01

    Banding has proven to be a useful technique in the study of population dynamics of avian species. However, band loss has long been recognized as a potential problem, (Hickey, 1952; Ludwig, 1967). Recently, Brownie et al. (1978) presented 14 models based on an array of explicit assumptions for the analysis of band recovery data. Various estimation models (assumption sets) allowed survival and/or recovery rates to be (a) constant, (b) time-specific, or (c) time- and age-specific. Optimal inference methods were employed and statistical tests of critical assumptions were developed and emphasized. The methods of Brownie et al. (1978), as with all previously published methods of which we are aware, assume no loss of bands during the study. However, some band loss is certain to occur and this potentially biases the estimates of annual survival rates whatever the analysis method. A few empirical studies have estimated band loss rates (a notable exception is Ludwig, 1967); consequently, for almost all band recovery data, the exact rate of band loss is unknown. In this paper we investigate the bias in estimates of annual survival rates due to varying degrees of hypothesized band loss. Our main results are based on perhaps the most useful model, originally developed by Seber (1970), for estimation of annual survival rate. Inferences are made concerning the bias of estimated survival rates in other models because the structure of these estimators is similar.

  4. The effects of numerical-model complexity and observation type on estimated porosity values

    NASA Astrophysics Data System (ADS)

    Starn, J. Jeffrey; Bagtzoglou, Amvrossios C.; Green, Christopher T.

    2015-09-01

    The relative merits of model complexity and types of observations employed in model calibration are compared. An existing groundwater flow model coupled with an advective transport simulation of the Salt Lake Valley, Utah (USA), is adapted for advective transport, and effective porosity is adjusted until simulated tritium concentrations match concentrations in samples from wells. Two calibration approaches are used: a "complex" highly parameterized porosity field and a "simple" parsimonious model of porosity distribution. The use of an atmospheric tracer (tritium in this case) and apparent ages (from tritium/helium) in model calibration also are discussed. Of the models tested, the complex model (with tritium concentrations and tritium/helium apparent ages) performs best. Although tritium breakthrough curves simulated by complex and simple models are very generally similar, and there is value in the simple model, the complex model is supported by a more realistic porosity distribution and a greater number of estimable parameters. Culling the best quality data did not lead to better calibration, possibly because of processes and aquifer characteristics that are not simulated. Despite many factors that contribute to shortcomings of both the models and the data, useful information is obtained from all the models evaluated. Although any particular prediction of tritium breakthrough may have large errors, overall, the models mimic observed trends.

  5. The effects of numerical-model complexity and observation type on estimated porosity values

    USGS Publications Warehouse

    Starn, Jeffrey; Bagtzoglou, Amvrossios C.; Green, Christopher T.

    2015-01-01

    The relative merits of model complexity and types of observations employed in model calibration are compared. An existing groundwater flow model coupled with an advective transport simulation of the Salt Lake Valley, Utah (USA), is adapted for advective transport, and effective porosity is adjusted until simulated tritium concentrations match concentrations in samples from wells. Two calibration approaches are used: a “complex” highly parameterized porosity field and a “simple” parsimonious model of porosity distribution. The use of an atmospheric tracer (tritium in this case) and apparent ages (from tritium/helium) in model calibration also are discussed. Of the models tested, the complex model (with tritium concentrations and tritium/helium apparent ages) performs best. Although tritium breakthrough curves simulated by complex and simple models are very generally similar, and there is value in the simple model, the complex model is supported by a more realistic porosity distribution and a greater number of estimable parameters. Culling the best quality data did not lead to better calibration, possibly because of processes and aquifer characteristics that are not simulated. Despite many factors that contribute to shortcomings of both the models and the data, useful information is obtained from all the models evaluated. Although any particular prediction of tritium breakthrough may have large errors, overall, the models mimic observed trends.

  6. A Generalized DIF Effect Variance Estimator for Measuring Unsigned Differential Test Functioning in Mixed Format Tests

    ERIC Educational Resources Information Center

    Penfield, Randall D.; Algina, James

    2006-01-01

    One approach to measuring unsigned differential test functioning is to estimate the variance of the differential item functioning (DIF) effect across the items of the test. This article proposes two estimators of the DIF effect variance for tests containing dichotomous and polytomous items. The proposed estimators are direct extensions of the…

  7. Effects of Autistic Traits on Social and School Adjustment in Children and Adolescents: The Moderating Roles of Age and Gender

    ERIC Educational Resources Information Center

    Hsiao, Mei-Ni; Tseng, Wan-Ling; Huang, Hui-Yi; Gau, Susan Shur-Fen

    2013-01-01

    This study examined the associations between children's and adolescents' autistic-like social deficits and school and social adjustment as well as the moderating roles of age and gender in these associations. The sample consisted of 1321 students (48.7% boys) in Grade 1 to Grade 8 from northern Taiwan. Children's and adolescents' autistic-like…

  8. The Effects of Child Sexual Abuse in Later Family Life; Mental Health, Parenting and Adjustment of Offspring

    ERIC Educational Resources Information Center

    Roberts, Ron; O'Connor, Tom; Dunn, Judy; Golding, Jean

    2004-01-01

    Objective: To investigate links between child sexual abuse (occurring before 13 years), later mental health, family organization, parenting behaviors, and adjustment in offspring. Method: The present study investigates a subsample of the Avon Longitudinal Study of Parents and Children an ongoing study of women and their families in the area of…

  9. The Effect of Undergraduate GPA Selectivity Adjustment on Pre-interview Ranking of Rural Medical School Applicants.

    ERIC Educational Resources Information Center

    Gilbert, Gregory Eastham; Blue, Amy Victoria; Basco, William Thomas, Jr.

    2003-01-01

    Almost all U.S. medical schools adjust applicants' GPAs based on the selectivity of applicants' undergraduate institutions. Analysis of data from 2,033 in-state applicants to the Medical University of South Carolina, 1996-99, found that this practice did not adversely affect the number of rural applicants offered admission interviews. (SV)

  10. The Adjustment Process for Individuals with Spinal Cord Injury: The Effect of Perceived Premorbid Sense of Coherence

    ERIC Educational Resources Information Center

    Lustig, Daniel C.

    2005-01-01

    This study investigated the relationship between perceived changes in sense of coherence from pre- to postinjury and adjustment for a group of individuals with spinal cord injury. It was hypothesized that after a spinal cord injury, an individual's belief that he or she had significantly reduced his or her sense of coherence would be associated…

  11. Using propensity score matching to estimate an "unbiased effect-size" between women's employment and partner violence in Tanzania.

    PubMed

    Vyas, Seema; Heise, Lori

    2014-11-01

    Estimates of the effect of employment on women's risk of partner violence in cross-sectional studies are subject to potential "self-selection bias." Women's personal choice of whether to pursue employment or not may create fundamental differences between the group of women who are employed and those who are not employed that standard regression methods cannot account for even after adjusting for confounding. The aim of this study is to demonstrate the utility of propensity score matching (PSM), a technique used widely in econometrics, to address this bias in cross-sectional studies. We use PSM to estimate an unbiased effect-size of women's employment on their risk of experiencing partner violence in urban and rural Tanzania using data from the 2010 Tanzania Demographic and Health Survey (DHS). Three different measures of women's employment were analyzed: whether they had engaged in any productive work outside of the home in the past year, whether they received payment in cash for this productive work, and whether their employment was stable. Women who worked outside of the home were significantly different from those who did not. In both urban and rural Tanzania, women's risk of violence appears higher among women who worked in the past year than among those who did not, even after using PSM to account for underlying differences in these two groups of women. Being paid in cash reversed this effect in rural areas whereas stability of employment reduced this risk in urban centers. The estimated size of effect varied by type of matching estimator, but the direction of the association remained largely consistent. This study's findings suggest substantial self-selection into employment. PSM methods, by compensating for this bias, appear to be a useful tool for estimating the relationship between women's employment and partner violence in cross-sectional studies.

  12. A note on variance estimation in random effects meta-regression.

    PubMed

    Sidik, Kurex; Jonkman, Jeffrey N

    2005-01-01

    For random effects meta-regression inference, variance estimation for the parameter estimates is discussed. Because estimated weights are used for meta-regression analysis in practice, the assumed or estimated covariance matrix used in meta-regression is not strictly correct, due to possible errors in estimating the weights. Therefore, this note investigates the use of a robust variance estimation approach for obtaining variances of the parameter estimates in random effects meta-regression inference. This method treats the assumed covariance matrix of the effect measure variables as a working covariance matrix. Using an example of meta-analysis data from clinical trials of a vaccine, the robust variance estimation approach is illustrated in comparison with two other methods of variance estimation. A simulation study is presented, comparing the three methods of variance estimation in terms of bias and coverage probability. We find that, despite the seeming suitability of the robust estimator for random effects meta-regression, the improved variance estimator of Knapp and Hartung (2003) yields the best performance among the three estimators, and thus may provide the best protection against errors in the estimated weights.

  13. Effects of live weight adjusted feeding strategy on plasma indicators of energy balance in Holstein cows managed for extended lactation.

    PubMed

    Gaillard, C; Vestergaard, M; Weisbjerg, M R; Sehested, J

    2016-04-01

    In early lactation, most of the dairy cows are in negative energy balance; the extent and duration depend in part on the feeding strategy. Previous studies showed an increased lactation milk yield by use of a live weight (LW) adjusted feeding strategy with a high energy diet before and a reduced energy diet after LW nadir compared with a standard diet throughout lactation. The objective of the present study was to examine how such an individualized feeding strategy affects plasma indicators of energy status. It was hypothesized that an energy-enriched diet until LW nadir will reduce the severity of the negative energy balance, and that the reduction in diet energy concentration from LW nadir will extend the negative energy balance period further. Sixty-two Holstein cows (30% first parity) were managed for 16 months extended lactation and randomly allocated to one of two feeding strategies at calving. Two partially mixed rations were used, one with a high energy density (HD) and a 50 : 50 forage : concentrate ratio, and one with a lower energy density (LD, control diet) and a 60 : 40 forage : concentrate ratio. Half of the cows were offered the HD diet until they reached at least 42 days in milk and a LW gain⩾0 kg/day based on a 5-days LW average, and were then shifted to the LD diet (strategy HD-LD). The other half of the cows were offered the LD diet throughout lactation (control strategy LD-LD). Weekly blood samples were drawn for analysis of plasma metabolites and hormones. Before the shift in diet, the HD-LD cows had higher glucose and lower beta-hydroxybutyrate and non-esterified fatty acids (NEFA) concentrations than the LD-LD cows. After the shift until 36 weeks after calving, plasma NEFA was higher in HD-LD than LD-LD cows. Insulin and insulin-like growth factor-1 were not affected by the feeding strategy. To conclude, in early lactation, the energy-enriched diet reduced the negative energy balance. Plasma NEFA was higher in HD-LD than LD-LD cows from

  14. Fine Mapping Seronegative and Seropositive Rheumatoid Arthritis to Shared and Distinct HLA Alleles by Adjusting for the Effects of Heterogeneity

    PubMed Central

    Han, Buhm; Diogo, Dorothée; Eyre, Steve; Kallberg, Henrik; Zhernakova, Alexandra; Bowes, John; Padyukov, Leonid; Okada, Yukinori; González-Gay, Miguel A.; Rantapää-Dahlqvist, Solbritt; Martin, Javier; Huizinga, Tom W.J.; Plenge, Robert M.; Worthington, Jane; Gregersen, Peter K.; Klareskog, Lars; de Bakker, Paul I.W.; Raychaudhuri, Soumya

    2014-01-01

    Despite progress in defining human leukocyte antigen (HLA) alleles for anti-citrullinated-protein-autoantibody-positive (ACPA+) rheumatoid arthritis (RA), identifying HLA alleles for ACPA-negative (ACPA−) RA has been challenging because of clinical heterogeneity within clinical cohorts. We imputed 8,961 classical HLA alleles, amino acids, and SNPs from Immunochip data in a discovery set of 2,406 ACPA− RA case and 13,930 control individuals. We developed a statistical approach to identify and adjust for clinical heterogeneity within ACPA− RA and observed independent associations for serine and leucine at position 11 in HLA-DRβ1 (p = 1.4 × 10−13, odds ratio [OR] = 1.30) and for aspartate at position 9 in HLA-B (p = 2.7 × 10−12, OR = 1.39) within the peptide binding grooves. These amino acid positions induced associations at HLA-DRB1∗03 (encoding serine at 11) and HLA-B∗08 (encoding aspartate at 9). We validated these findings in an independent set of 427 ACPA− case subjects, carefully phenotyped with a highly sensitive ACPA assay, and 1,691 control subjects (HLA-DRβ1 Ser11+Leu11: p = 5.8 × 10−4, OR = 1.28; HLA-B Asp9: p = 2.6 × 10−3, OR = 1.34). Although both amino acid sites drove risk of ACPA+ and ACPA− disease, the effects of individual residues at HLA-DRβ1 position 11 were distinct (p < 2.9 × 10−107). We also identified an association with ACPA+ RA at HLA-A position 77 (p = 2.7 × 10−8, OR = 0.85) in 7,279 ACPA+ RA case and 15,870 control subjects. These results contribute to mounting evidence that ACPA+ and ACPA− RA are genetically distinct and potentially have separate autoantigens contributing to pathogenesis. We expect that our approach might have broad applications in analyzing clinical conditions with heterogeneity at both major histocompatibility complex (MHC) and non-MHC regions. PMID:24656864

  15. Estimating Effects of Arsenic Exposure During Pregnancy on Perinatal Outcomes in a Bangladeshi Cohort

    PubMed Central

    Cardenas, Andres; Rodrigues, Ema; Mazumdar, Maitreyi; Dobson, Christine; Golam, Mostofa; Quamruzzaman, Quazi; Rahman, Mahmudar; Christiani, David C.

    2016-01-01

    Background: The relationship between arsenic and birth weight is not well understood. The objective was to evaluate the causal relationship between prenatal arsenic exposure and birth weight considering the potential mediation effects of gestational age and maternal weight gain during pregnancy using structural equation models. Methods: A prospectively enrolled cohort of pregnant women was recruited in Bangladesh from 2008 to 2011. Arsenic was measured in personal drinking water at the time of enrollment (gestational age <16 weeks, N = 1,140) and in toenails collected ≤1 month postpartum (N = 624) using inductively coupled plasma mass spectrometry. Structural equation models estimated the direct and indirect effects of arsenic on birth weight with gestational age and maternal weight gain considered as mediating variables. Results: Every unit increase in natural log water arsenic was indirectly associated with decreased birth weight (β = −19.17 g, 95% confidence interval [CI]: −24.64, −13.69) after adjusting for other risk factors. This association was mediated entirely through gestational age (β = −17.37 g, 95% CI: −22.77, −11.98) and maternal weight gain during pregnancy (β = −1.80 g, 95% CI: −3.72, 0.13). When exposure was modeled using toenail arsenic concentrations, similar results were observed. Every increase in natural log toenail arsenic was indirectly associated with decreased birth weight (β = −15.72 g, 95% CI: −24.52, −6.91) which was mediated through gestational age (β = −13.59 g, 95% CI: −22.10, −5.07) and maternal weight gain during pregnancy (β = −2.13 g, 95% CI: −5.24, 0.96). Conclusion: Arsenic exposure during pregnancy was associated with lower birth weight. The effect of arsenic on birth weight appears to be mediated mainly through decreasing gestational age and to a lesser extent by lower maternal weight gain during pregnancy. PMID:26583609

  16. Estimates of the Effective Elastic Thickness: Any signs of agreement?

    NASA Astrophysics Data System (ADS)

    McKenzie, Dan

    2016-04-01

    There is little controversy about the value of Te estimated from oceanic measurements of gravity and bathymetry. Its value is often obtained from the relationship between the free air gravity and bathymetry in the spectral domain. Estimates of Te from those few regions where there is good 2D bathymetric coverage give values which vary from 2-4 km for spreading ridges to ˜ 20 km for old lithosphere like that beneath Hawaii. There is a general belief that the elastic thickness is controlled by the depth of an isotherm whose value is ˜ 450°C, and that Te < T_s, the seismogenic thickness, which closely follows the 600°C isotherm. In contrast, there is no agreement between different estimates of Te from continents, most of which are based on Forsyth's method using the coherence between Bouguer gravity and topography. In regions of rough topography his approach gives estimates of Te that are similar to, though generally about double, those obtained from the free air gravity using the same approach as in the oceans. However, in regions with little topography, which includes most shields, the ratio between the two estimates often exceeds a factor of 5, with estimates of Te from Forsyth's method often exceeding 100 km, corresponding to a limiting isotherm of 1000°C or more. Laboratory experiments at such temperatures show that elastic stresses are relaxed in hours. This problem has generated a long running controversy. It is straightforward to show that estimates of Te from Bouguer gravity depend only on the ratio of the power spectra of free air gravity to topography when the two are incoherent (McK, 2015), and are independent of the actual value of T_e. In many shield regions the topography is indeed incoherent with the topography. No valid estimates of Te can then be obtained. However, it is nonetheless often possible to use the spectral ratio to estimate an upper bound on the value of T_e, which is generally < 30 km. Accurate maps of topography and gravity are now

  17. Three-dimensional adjustment of trilateration data

    NASA Technical Reports Server (NTRS)

    Sung, L.-Y.; Jackson, D. D.

    1985-01-01

    The three-dimensional locations of the monuments in the USGS Hollister trilateration network were adjusted to fit line length observations observed in 1977, using a Bayesian approach, and incorporating prior elevation estimates as data in the adjustment procedure. No significant discrepancies in the measured line lengths were found, but significant elevation adjustments (up to 1.85 m) were needed to fit the length data.

  18. Estimating the effectiveness of a hospital’s interventions in India: impact of the choice of disability weights

    PubMed Central

    Gosselin, Richard A

    2015-01-01

    Abstract Objective To calculate the effect of using two different sets of disability weights for estimates of disability-adjusted life-years (DALYs) averted by interventions delivered in one hospital in India. Methods DALYs averted by surgical and non-surgical interventions were estimated for 3445 patients who were admitted to a 106-bed private hospital in a semi-urban area of northern India in 2012–2013. Disability weights were taken from global burden of disease (GBD) studies. We used the GBD 1990 disability weights and then repeated all of our calculations using the corresponding GBD 2010 weights. DALYs averted were estimated for surgical and non-surgical interventions using disability weight, risk of death and/or disability, and effectiveness of treatment. Findings The disability weights assigned in the GBD 1990 study to the sequelae of conditions such as cataract, cancer and injuries were substantially different to those assigned in the GBD 2010 study. These differences in weights led to large differences in estimates of DALYs averted. For all surgical interventions delivered to this patient cohort, 11 517 DALYs were averted if we used the GDB 1990 weights and 9401 DALYs were averted if we used the GDB 2010 disability weights. For non-surgical interventions 5168 DALYs were averted using the GDB 1990 disability weights and 5537 DALYS were averted using the GDB 2010 disability weights. Conclusion Estimates of the effectiveness of hospital interventions depend upon the disability weighting used. Researchers and resource allocators need to be very cautious when comparing results from studies that have used different sets of disability weights. PMID:26170505

  19. Parental physical punishment and adolescent adjustment: bidirectionality and the moderation effects of child ethnicity and parental warmth.

    PubMed

    Wang, Ming-Te; Kenny, Sarah

    2014-01-01

    This study used cross-lagged modeling to examine reciprocal relations between maternal and paternal physical punishment and adolescent misconduct and depressive symptoms, while accounting for stability in both physical punishment and adjustment problems over time. Data were drawn from a sample of 862 two-parent families and their adolescent children (52 % males; 54 % European American; 44 % African American; 2 % other ethnic backgrounds). Mothers' and fathers' physical punishment of their adolescents' ages 12 and 14 predicted increased misconduct and depressive symptoms among these adolescents at ages 14 and 16. Adolescent misconduct, but not depressive symptoms, at ages 12 and 14 predicted increased physical punishment by their parents at ages 14 and 16. Neither parental warmth nor child ethnicity moderated the longitudinal relationship between parental physical punishment and adolescent adjustment. Patterns of findings were similar across mothers and fathers.

  20. Parental physical punishment and adolescent adjustment: bidirectionality and the moderation effects of child ethnicity and parental warmth.

    PubMed

    Wang, Ming-Te; Kenny, Sarah

    2014-01-01

    This study used cross-lagged modeling to examine reciprocal relations between maternal and paternal physical punishment and adolescent misconduct and depressive symptoms, while accounting for stability in both physical punishment and adjustment problems over time. Data were drawn from a sample of 862 two-parent families and their adolescent children (52 % males; 54 % European American; 44 % African American; 2 % other ethnic backgrounds). Mothers' and fathers' physical punishment of their adolescents' ages 12 and 14 predicted increased misconduct and depressive symptoms among these adolescents at ages 14 and 16. Adolescent misconduct, but not depressive symptoms, at ages 12 and 14 predicted increased physical punishment by their parents at ages 14 and 16. Neither parental warmth nor child ethnicity moderated the longitudinal relationship between parental physical punishment and adolescent adjustment. Patterns of findings were similar across mothers and fathers. PMID:24384596

  1. Relation Between Health-Related Quality of Life and Sleep Quality With Adjustment for Comorbidity Among the Korean Elderly: Mixed-Effects Model With a 6-Year Follow-up Study.

    PubMed

    Kwon, Amy M; Shin, Chol

    2016-04-01

    It is an important public health problem to identify risk factors of health-related quality of life (HRQoL) among the elderly. We recruited subjects from Ansan, Korea, as a subset of the Korean Genome and Epidemiology Study (KoGES), which is an ongoing population study, and followed up their sleep quality for 6 years. Mixed effect models were used to estimate the association between sleep quality and HRQoL, and we found that overall HRQoL was significantly lower to the elderly having poor sleep quality with adjustment for significant covariates although sleep quality showed a significant interaction effect with time for the mental component summary of SF-12. In particular, the elderly having lack of quality sleep appeared to have good general health, but their functional performances were significantly poor.

  2. Effects of molybdenum on water utilization, antioxidative defense system and osmotic-adjustment ability in winter wheat (Triticum aestivum) under drought stress.

    PubMed

    Wu, Songwei; Hu, Chengxiao; Tan, Qiling; Nie, Zhaojun; Sun, Xuecheng

    2014-10-01

    Molybdenum (Mo), as an essential trace element in plants, plays an essential role in abiotic stress tolerance of plants. To obtain a better understanding of drought tolerance enhanced by Mo, a hydroponic trial was conducted to investigate the effects of Mo on water utilization, antioxidant enzymes, non-enzymatic antioxidants, and osmotic-adjustment products in the Mo-efficient '97003' and Mo-inefficient '97014' under PEG simulated drought stress. Our results indicate that Mo application significantly enhanced Pn, chlorophyll, dry matter, grain yield, biomass, RWC and WUE and decreased Tr, Gs and water loss of wheat under drought stress, suggesting that Mo application improved the water utilization capacity in wheat. The activities of antioxidant enzymes such as superoxide dismutase, peroxidase, catalase, ascorbate peroxidase and the contents of non-enzymatic antioxidants content such as ascorbic acid, reduced glutathione, carotenoid were significantly increased and malonaldehyde contents were decreased by Mo application under PEG simulated drought stress, suggesting that Mo application enhanced the ability of scavenging active oxygen species. The osmotic-adjustment products such as soluble protein, proline and soluble sugar were also increased by Mo application under PEG simulated drought stress, indicating that Mo improved the osmotic adjustment ability in wheat. It is hypothesized that Mo application might improve the drought tolerance of wheat by enhancing water utilization capability and the abilities of antioxidative defense and osmotic adjustment. Similarities and differences between the Mo-efficient and Mo-inefficient cultivars wheat in response to Mo under drought stress are discussed.

  3. Estimating the effects of cigarette taxes on birth outcomes.

    PubMed

    Sen, Anindya; Piérard, Emmanuelle

    2011-01-01

    Employing provincial data from 1979 to 2004 allows us to exploit the significant (45 percent to 60 percent) reduction in excise taxes in Eastern Canada enacted in February 1994 to estimate the impacts of cigarette taxes on birth outcomes. Empirical estimates suggest that an increase in cigarette taxes is significantly associated with lower infant mortalities. However, we also find some evidence of a counter-intuitive positive correlation between taxes and fetal deaths. Overall, conditional on methodology, we find increased lagged per capita health expenditures and the number of physicians to be significantly associated with improvements in birth outcomes.

  4. Estimating the Effects of the Terminal Area Productivity Program

    NASA Technical Reports Server (NTRS)

    Lee, David A.; Kostiuk, Peter F.; Hemm, Robert V., Jr.; Wingrove, Earl R., III; Shapiro, Gerald

    1997-01-01

    The report describes methods and results of an analysis of the technical and economic benefits of the systems to be developed in the NASA Terminal Area Productivity (TAP) program. A runway capacity model using parameters that reflect the potential impact of the TAP technologies is described. The runway capacity model feeds airport specific models which are also described. The capacity estimates are used with a queuing model to calculate aircraft delays, and TAP benefits are determined by calculating the savings due to reduced delays. The report includes benefit estimates for Boston Logan and Detroit Wayne County airports. An appendix includes a description and listing of the runway capacity model.

  5. Effects of exposure uncertainty on estimation of radon risks

    SciTech Connect

    Chambers, D.B.; Lowe, L.M.; Stager, R.H.; Reilly, P.M.; Duport, P.

    1992-12-31

    Estimates of lung-cancer risk from exposure to radon daughters are largely based on epidemiological studies of underground miners. The reliability of exposure data for these miners is a cause for concern, as actual workplace measurements of radon and/or radon-daughter levels are either sparse or absent for the early years of mining, when much of the exposure occurred.

  6. Survival estimation and the effects of dependency among animals

    USGS Publications Warehouse

    Schmutz, Joel A.; Ward, David H.; Sedinger, James S.; Rexstad, Eric A.

    1995-01-01

    Survival models assume that fates of individuals are independent, yet the robustness of this assumption has been poorly quantified. We examine how empirically derived estimates of the variance of survival rates are affected by dependency in survival probability among individuals. We used Monte Carlo simulations to generate known amounts of dependency among pairs of individuals and analyzed these data with Kaplan-Meier and Cormack-Jolly-Seber models. Dependency significantly increased these empirical variances as compared to theoretically derived estimates of variance from the same populations. Using resighting data from 168 pairs of black brant, we used a resampling procedure and program RELEASE to estimate empirical and mean theoretical variances. We estimated that the relationship between paired individuals caused the empirical variance of the survival rate to be 155% larger than the empirical variance for unpaired individuals. Monte Carlo simulations and use of this resampling strategy can provide investigators with information on how robust their data are to this common assumption of independent survival probabilities.

  7. Attributes Effecting Software Testing Estimation; Is Organizational Trust an Issue?

    ERIC Educational Resources Information Center

    Hammoud, Wissam

    2013-01-01

    This quantitative correlational research explored the potential association between the levels of organizational trust and the software testing estimation. This was conducted by exploring the relationships between organizational trust, tester's expertise, organizational technology used, and the number of hours, number of testers, and time-coding…

  8. Effect of discounting on estimation of benefits determined by hepatitis C treatment

    PubMed Central

    Messori, Andrea; Fadda, Valeria; Maratea, Dario; Trippoli, Sabrina

    2012-01-01

    The combination of either boceprevir or telaprevir with ribavirin and interferon (triple therapy) has been shown to be more effective than ribavirin+interferon (dual therapy) for the treatment of genotype 1 hepatitis C. Since the benefit of these treatments takes place after years, simulation models are needed to predict long-term outcomes. In simulation models, the choice of different values of yearly discount rates (e.g., 6%, 3.5%, 2%, 1.5% or 0%) influences the results, but no studies have specifically addressed this issue. We examined this point by determining the long-term benefits under different conditions on the basis of standard modelling and using quality-adjusted life years (QALYs) to quantify the benefits. In our base case scenario, we compared the long-term benefit between patients given a treatment with a 40% sustained virologic response (SVR) (dual therapy) and patients given a treatment with a 70% SVR (triple therapy), and we then examined how these specific yearly discount rates influenced the incremental benefit. The gain between a 70% SVR and a 40% SVR decreased from 0.45 QALYs with a 0% discount rate to 0.22 QALYs with a 6% discount rate (ratio between the two values = 2.04). Testing the other discounting assumptions confirmed that the discount rate has a marked impact on the magnitude of the model-estimated incremental benefit. In conclusion, the results of our analysis can be helpful to better interpret cost-effectiveness studies evaluating new treatment for hepatitis C. PMID:22736930

  9. Part 3. Estimating the effects of air pollution on mortality in Bangkok, Thailand.

    PubMed

    Vichit-Vadakan, Nuntavarn; Vajanapoom, Nitaya; Ostro, Bart

    2010-11-01

    pollution and cold weather, with its associated adverse health problems. Multiday averages of PM10 generated even higher effect estimates. Our analysis of age- and disease-specific mortality indicated elevated ERs for young children, especially infants with respiratory illnesses, children less than 5 years of age with lower respiratory infections (LRIs), and people with asthma. Age-restricted analyses showed that the associations between mortality due to all natural causes and PM10 concentration increased with age, with the strongest effects among people aged 75 years and older. However, associations between increases in PM10 concentration and mortality were observed for all of the other age groups. With a few exceptions, relatively similar results were observed for several of the other pollutants-sulfur dioxide (SO2), NO2, O3, and NO, which were highly correlated with PM10. However, many of the effects from gaseous pollutants were attenuated in multipollutant models, while effects from PM10 appeared to be most consistent. In addition, there was some evidence of an independent effect of O3 for certain health outcomes. We conducted substantial sensitivity analyses to examine whether our results were robust. The results indicated that our core model was generally robust to the choice of model specification, spline model, degrees of freedom (df) of time-smoothing functions, lags for temperature, adjustment for autocorrelation, adjustment for epidemics, and adjustment for missing values using centered data (see the description of the centering method used in the Common Protocol found at the end of this volume). Finally, the concentration-response functions for most of the pollutants appear to be linear. Thus, our sensitivity analyses results suggest an impact of pollution on mortality in Bangkok that is fairly consistent. They also provide support for the extrapolation of results from health effects studies conducted in North America and Western Europe to other parts of the

  10. The effect of errors-in-variables on variance component estimation

    NASA Astrophysics Data System (ADS)

    Xu, Peiliang

    2016-08-01

    Although total least squares (TLS) has been widely applied, variance components in an errors-in-variables (EIV) model can be inestimable under certain conditions and unstable in the sense that small random errors can result in very large errors in the estimated variance components. We investigate the effect of the random design matrix on variance component (VC) estimation of MINQUE type by treating the design matrix as if it were errors-free, derive the first-order bias of the VC estimate, and construct bias-corrected VC estimators. As a special case, we obtain a bias-corrected estimate for the variance of unit weight. Although TLS methods are statistically rigorous, they can be computationally too expensive. We directly Taylor-expand the nonlinear weighted LS estimate of parameters up to the second-order approximation in terms of the random errors of the design matrix, derive the bias of the estimate, and use it to construct a bias-corrected weighted LS estimate. Bearing in mind that the random errors of the design matrix will create a bias in the normal matrix of the weighted LS estimate, we propose to calibrate the normal matrix by computing and then removing the bias from the normal matrix. As a result, we can obtain a new parameter estimate, which is called the N-calibrated weighted LS estimate. The simulations have shown that (i) errors-in-variables have a significant effect on VC estimation, if they are large/significant but treated as non-random. The variance components can be incorrectly estimated by more than one order of magnitude, depending on the nature of problems and the sizes of EIV; (ii) the bias-corrected VC estimate can effectively remove the bias of the VC estimate. If the signal-to-noise is small, higher order terms may be necessary. Nevertheless, since we construct the bias-corrected VC estimate by directly removing the estimated bias from the estimate itself, the simulation results have clearly indicated that there is a great risk to obtain

  11. Eliminating artificial trans fatty acids in Argentina: estimated effects on the burden of coronary heart disease and costs

    PubMed Central

    Elorriaga, Natalia; Garay, Osvaldo U; Poggio, Rosana; Caporale, Joaquin; Matta, Maria G; Augustovski, Federico; Pichon-Riviere, Andres; Mozaffarian, Dariush

    2015-01-01

    Abstract Objective To estimate the impact of Argentine policies to reduce trans fatty acids (TFA) on coronary heart disease (CHD), disability-adjusted life years (DALYs) and associated health-care costs. Methods We estimated the baseline intake of TFA before 2004 to be 1.5% of total energy intake. We built a policy model including baseline intake of TFA, the oils and fats used to replace artificial TFAs, the clinical effect of reducing artificial TFAs and the costs and DALYs saved due to averted CHD events. To calculate the percentage of reduction of CHD, we calculated CHD risks on a population-based sample before and after implementation. The effect of the policies was modelled in three ways, based on projected changes: (i) in plasma lipid profiles; (ii) in lipid and inflammatory biomarkers; and (iii) the results of prospective cohort studies. We also estimated the present economic value of DALYs and associated health-care costs of coronary heart disease averted. Findings We estimated that projected changes in lipid profile would avert 301 deaths, 1066 acute CHD events, 5237 DALYs and 17 million United States dollars (US$) in health-care costs annually. Based on the adverse effects of TFA intake reported in prospective cohort studies, 1517 deaths, 5373 acute CHD events, 26 394 DALYs and US$ 87 million would be averted annually. Conclusion Even under the most conservative scenario, reduction of TFA intake had a substantial effect on public health. These findings will help inform decision-makers in Argentina and other countries on the potential public health and economic impact of this policy. PMID:26478625

  12. The Effect of the Neurac Sling Exercise on Postural Balance Adjustment and Muscular Response Patterns in Chronic Low Back Pain Patients

    PubMed Central

    Kim, Ji Hae; Kim, Young Eok; Bae, Sea Hyun; Kim, Kyung Yoon

    2013-01-01

    [Purpose] This study aimed to examine the effects of the Neurac sling exercise on postural balance adjustment and muscular response patterns in chronic low back pain (CLBP) patients. [Subjects and Methods] Sixteen CLBP patients participated in this study. They were randomly and equally assigned to group I, whose members received ordinary physical therapy (40 minutes per time, four times per week), and group II, whose members performed a lumbar stabilization exercise using the Neurac sling after ordinary physical therapy (40 minutes per time, four times per week). The visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate exercise effects. BioRescue and electromyography were utilized for the measurement of changes in postural balance adjustment and muscular response patterns, respectively. [Results] Both groups saw their VAS and ODI decrease significantly. There were significant decreases in both groups in posturography as well, but group II recorded a greater decrease. There were significant increases in the flexion–relaxation ratio in both groups, and there were significant increases in the extension–flexion ratio in the left L1–2 of group I and in all elements of group II. [Conclusion] Lumbar stabilization exercise using the Neurac sling is effective in decreasing pain, improving damaged postural balance adjustment, and normalizing muscle response patterns of CLBP patients. PMID:24259906

  13. Effect of delayed reporting of band recoveries on survival estimates

    USGS Publications Warehouse

    Anderson, David R.; Burnham, Kenneth P.

    1980-01-01

    Brownie et al. (U.S. Fish and Wildl. Serv., Resource Publ. 131, 1978) presented 14 models based on an array of explicit assumptions for the study of survival in avian populations. These methods are replacing the life table methods previously used to estimate survival rates (e.g., Burnham and Anderson, J. Wildl. Manage., 43: 356-366, 1979). The new methods allow survival or recovery rates, or both, to be constant, time-specific, or time- and age-specific. In studies to estimate survival rates for birds the data are often from recoveries of birds shot or found dead during the hunting season and reported to the Bird Banding Laboratory by sportsmen, conservation agency employees, or the general public. This note examines the bias in estimating annual survival due to a proportion of the recoveries being incorrectly reported a year late. Specifically, a few recoveries each year of, for example, adult male American Widgeon (Anas americana) banded in California are reported as being recovered in year i + 1 when in fact they were actually recovered the previous year i. Delayed reporting might typically be caused by people finding a band in their health clothing in the fall of the year and, being embarrassed about their failure to report the band when it was taken, report it a year late not mentioning the actual year of recovery. Heuristically, delayed reporting should bias estimated annual survival rates upwards because it appears from the data that the birds corresponding to the "delayed" recoveries actually lived an additional year.

  14. Estimating Unsaturated Hydraulic Conductivity: Study the Effect of Tortuosity Factor

    NASA Astrophysics Data System (ADS)

    Ghanbarian-Alavijeh, Behzad; Abbasi, Fariborz

    2010-05-01

    Unsaturated soil hydraulic conductivity is one of the key soil hydraulic properties that, in one hand, is widely used in the studies of water and solute transport in soils, and on the other hand its direct measurement is time consuming and expensive. In this research, in order to study tortuosity factor (l) in the Burdine-Brooks-Corey (BBC hereafter), 59 soil samples from the GRIZZLY database were used. Using a sensitivity analysis, sensitive parameters of this model were determined. To study tortuosity factor, its different values e.g. 2, 1, 0.5, 0, -0.5, -1 and -2 were used in the estimation of unsaturated hydraulic conductivity. The results of sensitivity analysis showed that BBC model is more sensitive to the saturated water content and pore size distribution index. Whereas, the BBC model is less sensitive to tortuosity factor and saturated hydraulic conductivity. The calculated statistical parameter SAE in estimation of unsaturated hydraulic conductivity indicated that the BBC model error with l=2 is less than other values. The results also showed that tortuosity factor is linearly correlated with the power of BCC model with goodness of fit R2=0.96. Based on this approach, tortuosity factor was removed from BCC model, and a new empirical equation was developed to estimate unsaturated hydraulic conductivity. This model was verified using 33 samples of the UNSODA database. The results showed that the developed empirical equation estimated unsaturated hydraulic conductivity better than BCC model in which tortuosity factor was assumed to be equal to 2. Acknowledgments The authors are grateful to Drs. M.Th. van Genuchten and R. Haverkamp for providing the UNSODA and GRIZZLY data sets.

  15. ADJUSTABLE DOUBLE PULSE GENERATOR

    DOEpatents

    Gratian, J.W.; Gratian, A.C.

    1961-08-01

    >A modulator pulse source having adjustable pulse width and adjustable pulse spacing is described. The generator consists of a cross coupled multivibrator having adjustable time constant circuitry in each leg, an adjustable differentiating circuit in the output of each leg, a mixing and rectifying circuit for combining the differentiated pulses and generating in its output a resultant sequence of negative pulses, and a final amplifying circuit for inverting and square-topping the pulses. (AEC)

  16. The relationship between effectiveness and costs measured by a risk-adjusted case-mix system: multicentre study of Catalonian population data bases

    PubMed Central

    Sicras-Mainar, Antoni; Navarro-Artieda, Ruth; Blanca-Tamayo, Milagrosa; Velasco-Velasco, Soledad; Escribano-Herranz, Esperanza; Llopart-López, Josep Ramon; Violan-Fors, Concepción; Vilaseca-Llobet, Josep Maria; Sánchez-Fontcuberta, Encarna; Benavent-Areu, Jaume; Flor-Serra, Ferran; Aguado-Jodar, Alba; Rodríguez-López, Daniel; Prados-Torres, Alejandra; Estelrich-Bennasar, Jose

    2009-01-01

    Background The main objective of this study is to measure the relationship between morbidity, direct health care costs and the degree of clinical effectiveness (resolution) of health centres and health professionals by the retrospective application of Adjusted Clinical Groups in a Spanish population setting. The secondary objectives are to determine the factors determining inadequate correlations and the opinion of health professionals on these instruments. Methods/Design We will carry out a multi-centre, retrospective study using patient records from 15 primary health care centres and population data bases. The main measurements will be: general variables (age and sex, centre, service [family medicine, paediatrics], and medical unit), dependent variables (mean number of visits, episodes and direct costs), co-morbidity (Johns Hopkins University Adjusted Clinical Groups Case-Mix System) and effectiveness. The totality of centres/patients will be considered as the standard for comparison. The efficiency index for visits, tests (laboratory, radiology, others), referrals, pharmaceutical prescriptions and total will be calculated as the ratio: observed variables/variables expected by indirect standardization. The model of cost/patient/year will differentiate fixed/semi-fixed (visits) costs of the variables for each patient attended/year (N = 350,000 inhabitants). The mean relative weights of the cost of care will be obtained. The effectiveness will be measured using a set of 50 indicators of process, efficiency and/or health results, and an adjusted synthetic index will be constructed (method: percentile 50). The correlation between the efficiency (relative-weights) and synthetic (by centre and physician) indices will be established using the coefficient of determination. The opinion/degree of acceptance of physicians (N = 1,000) will be measured using a structured questionnaire including various dimensions. Statistical analysis: multiple regression analysis (procedure

  17. The effect of land cover heterogeneity of MODIS pixel on canopy LAI estimation

    NASA Astrophysics Data System (ADS)

    Manninen, T.; Puttonen, N.

    2012-04-01

    The boreal zone land cover has a very significant influence on the northern hemisphere albedo and is an important component of the northern hemisphere carbon budget. Both albedo and the leaf area index (LAI) are one of the most important biophysical vegetation parameters and belong to the Essential Climate Variables (ECV) . In addition, in winter time the boreal forest albedo is a complicated combination of snow and canopy radiative properties, so that the albedo is a function of the canopy LAI. One possibility to estimate LAI using optical satellite data is by determination of spectral vegetation indices (SVIs), such as the reduced simple ratio (RSR). It uses the visible near infrared and short wave infrared channels. In large areas moderate resolution instruments, like MODIS, are suitable for LAI mapping. Yet, the heterogeneity of land cover in many boreal areas, for example in Finland, causes a challenge for LAI estimation. This effect was studied using several Landsat and MODIS images and the high resolution CORINE land cover map covering the same area in various parts of Finland. The atmospheric correction of the Landsat images was adjusted so that each MODIS pixel reflectance matched the average of the Landsat pixel reflectances within the MODIS pixel. The LAI values for Landsat and MODIS images were then determined using the RSR index. The LAI average of forested Landsat pixels was compared to the corresponding MODIS pixel LAI as a function of open water area fraction in the MODIS pixel. A regression function was determined to derive a method to correct the MODIS based LAI values with the open water area fraction. It turned out that the existence of open water in the MODIS pixels reduces the determined canopy LAI value on the average 30%. Also other land cover classes affect the LAI value, but the effect of water is largest, because the reflectance of water deviates so much from that of the canopy. The canopy LAI map of whole Finland was then calculated

  18. Biased Exposure–Health Effect Estimates from Selection in Cohort Studies: Are Environmental Studies at Particular Risk?

    PubMed Central

    Sparrow, David; Hu, Howard; Power, Melinda C.

    2015-01-01

    Background The process of creating a cohort or cohort substudy may induce misleading exposure–health effect associations through collider stratification bias (i.e., selection bias) or bias due to conditioning on an intermediate. Studies of environmental risk factors may be at particular risk. Objectives We aimed to demonstrate how such biases of the exposure–health effect association arise and how one may mitigate them. Methods We used directed acyclic graphs and the example of bone lead and mortality (all-cause, cardiovascular, and ischemic heart disease) among 835 white men in the Normative Aging Study (NAS) to illustrate potential bias related to recruitment into the NAS and the bone lead substudy. We then applied methods (adjustment, restriction, and inverse probability of attrition weighting) to mitigate these biases in analyses using Cox proportional hazards models to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Results Analyses adjusted for age at bone lead measurement, smoking, and education among all men found HRs (95% CI) for the highest versus lowest tertile of patella lead of 1.34 (0.90, 2.00), 1.46 (0.86, 2.48), and 2.01 (0.86, 4.68) for all-cause, cardiovascular, and ischemic heart disease mortality, respectively. After applying methods to mitigate the biases, the HR (95% CI) among the 637 men analyzed were 1.86 (1.12, 3.09), 2.47 (1.23, 4.96), and 5.20 (1.61, 16.8), respectively. Conclusions Careful attention to the underlying structure of the observed data is critical to identifying potential biases and methods to mitigate them. Understanding factors that influence initial study participation and study loss to follow-up is critical. Recruitment of population-based samples and enrolling participants at a younger age, before the potential onset of exposure-related health effects, can help reduce these potential pitfalls. Citation Weisskopf MG, Sparrow D, Hu H, Power MC. 2015. Biased exposure–health effect estimates

  19. The Effects of School-Based Maum Meditation Program on the Self-Esteem and School Adjustment in Primary School Students

    PubMed Central

    Yoo, Yang Gyeong; Lee, In Soo

    2013-01-01

    Self-esteem and school adjustment of children in the lower grades of primary school, the beginning stage of school life, have a close relationship with development of personality, mental health and characters of children. Therefore, the present study aimed to verify the effect of school-based Maum Meditation program on children in the lower grades of primary school, as a personality education program. The result showed that the experimental group with application of Maum Meditation program had significant improvements in self-esteem and school adjustment, compared to the control group without the application. In conclusion, since the study provides significant evidence that the intervention of Maum Meditation program had positive effects on self-esteem and school adjustment of children in the early stage of primary school, it is suggested to actively employ Maum Meditation as a school-based meditation program for mental health promotion of children in the early school ages, the stage of formation of personalities and habits. PMID:23777717

  20. Estimating Peer Effects in Sexual Behavior among Adolescents

    ERIC Educational Resources Information Center

    Ali, Mir M.; Dwyer, Debra S.

    2011-01-01

    In this paper we seek to empirically quantify the role of peer social networks in influencing sexual behavior among adolescents. Using data of a nationally representative sample of adolescents we utilize a multivariate structural model with school-level fixed effects to account for the problems of contextual effects, correlated effects and peer…

  1. Correcting Bias Caused by Missing Data in the Estimate of the Effect of Apolipoprotein ε4 on Cognitive Decline.

    PubMed

    Hall, Charles B; Lipton, Richard B; Katz, Mindy J; Wang, Cuiling

    2015-01-01

    Longitudinal administration of neuropsychological instruments are often used to assess age-related changes in cognition. Informative loss to follow-up may bias the results of these studies. Herein, we use auxiliary data to adjust for informative loss to follow-up. In the Einstein Aging Study, memory was assessed annually in a community sample of adults age 70+, free of dementia at baseline, using the free recall from the Free and Cued Selective Reminding Test, and via telephone using the Memory Impairment Screen for Telephone (the auxiliary data). Joint linear mixed models were used to assess how the effect of the APOE ε4 genotype may be affected by informative missingness in the in-person data. A total of 620 EAS participants contributed 2085 person years of follow-up to the analyses. Memory decline rates estimated in joint models were 19% greater in ε4 negative participants and 27% greater in ε4 positive participants compared to traditional approaches; the effect of APOE ε4 on memory decline was 37% greater. Joint modeling methods can help address bias caused by informative missing data in the estimation of the effect of risk factors on cognitive change, and may be applicable to a broader range of outcomes in longitudinal aging studies. PMID:25389642

  2. Correcting bias caused by missing data in the estimate of the effect of apolipoprotein ε4 on cognitive decline

    PubMed Central

    Hall, Charles B.; Lipton, Richard B.; Katz, Mindy J.; Wang, Cuiling

    2014-01-01

    Objective Longitudinal administration of neuropsychological instruments are often used to assess age-related changes in cognition. Informative loss to follow-up may bias the results of these studies. Herein, we use auxiliary data to adjust for informative loss to follow-up. Method In the Einstein Aging Study, memory was assessed annually in a community sample of adults age 70+, free of dementia at baseline, using the free recall from the Free and Cued Selective Reminding Test, and via telephone using the Memory Impairment Screen for Telephone (the auxiliary data). Joint linear mixed models were used to assess how the effect of the APOE ε4 genotype may be affected by informative missingness in the in-person data. Results 620 EAS participants contributed 2085 person years of follow-up to the analyses. Memory decline rates estimated in joint models were 19% greater in ε4 negative participants and 27% greater in ε4 positive participants compared to traditional approaches; the effect of APOE ε4 on memory decline was 37% greater. Conclusions Joint modelling methods can help address bias caused by informative missing data in the estimation of the effect of risk factors on cognitive change, and may be applicable to a broader range of outcomes in longitudinal aging studies. PMID:25389642

  3. Estimation of Effect Size Under Nonrandom Sampling: The Effects of Censoring Studies Yielding Statistically Insignificant Mean Differences.

    ERIC Educational Resources Information Center

    Hedges, Larry V.

    1984-01-01

    If the quantitative result of a study is observed only when the mean difference is statistically significant, the observed mean difference, variance, and effect size are biased estimators of corresponding population parameters. The exact distribution of sample effect size and the maximum likelihood estimator of effect size are derived. (Author/BW)

  4. The effect of weak lensing on distance estimates from supernovae

    SciTech Connect

    Smith, Mathew; Maartens, Roy; Bacon, David J.; Nichol, Robert C.; Campbell, Heather; D'Andrea, Chris B.; Clarkson, Chris; Bassett, Bruce A.; Cinabro, David; Finley, David A.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; Olmstead, Matthew D.; Schneider, Donald P.; Shapiro, Charles; Sollerman, Jesper

    2014-01-01

    Using a sample of 608 Type Ia supernovae from the SDSS-II and BOSS surveys, combined with a sample of foreground galaxies from SDSS-II, we estimate the weak lensing convergence for each supernova line of sight. We find that the correlation between this measurement and the Hubble residuals is consistent with the prediction from lensing (at a significance of 1.7σ). Strong correlations are also found between the residuals and supernova nuisance parameters after a linear correction is applied. When these other correlations are taken into account, the lensing signal is detected at 1.4σ. We show, for the first time, that distance estimates from supernovae can be improved when lensing is incorporated, by including a new parameter in the SALT2 methodology for determining distance moduli. The recovered value of the new parameter is consistent with the lensing prediction. Using cosmic microwave background data from WMAP7, H {sub 0} data from Hubble Space Telescope and Sloan Digital Sky Survey (SDSS) Baryon acoustic oscillations measurements, we find the best-fit value of the new lensing parameter and show that the central values and uncertainties on Ω {sub m} and w are unaffected. The lensing of supernovae, while only seen at marginal significance in this low-redshift sample, will be of vital importance for the next generation of surveys, such as DES and LSST, which will be systematics-dominated.

  5. Effects of parameter estimation on maximum-likelihood bootstrap analysis.

    PubMed

    Ripplinger, Jennifer; Abdo, Zaid; Sullivan, Jack

    2010-08-01

    Bipartition support in maximum-likelihood (ML) analysis is most commonly assessed using the nonparametric bootstrap. Although bootstrap replicates should theoretically be analyzed in the same manner as the original data, model selection is almost never conducted for bootstrap replicates, substitution-model parameters are often fixed to their maximum-likelihood estimates (MLEs) for the empirical data, and bootstrap replicates may be subjected to less rigorous heuristic search strategies than the original data set. Even though this approach may increase computational tractability, it may also lead to the recovery of suboptimal tree topologies and affect bootstrap values. However, since well-supported bipartitions are often recovered regardless of method, use of a less intensive bootstrap procedure may not significantly affect the results. In this study, we investigate the impact of parameter estimation (i.e., assessment of substitution-model parameters and tree topology) on ML bootstrap analysis. We find that while forgoing model selection and/or setting substitution-model parameters to their empirical MLEs may lead to significantly different bootstrap values, it probably would not change their biological interpretation. Similarly, even though the use of reduced search methods often results in significant differences among bootstrap values, only omitting branch swapping is likely to change any biological inferences drawn from the data.

  6. The effect of high leverage points on the logistic ridge regression estimator having multicollinearity

    NASA Astrophysics Data System (ADS)

    Ariffin, Syaiba Balqish; Midi, Habshah

    2014-06-01

    This article is concerned with the performance of logistic ridge regression estimation technique in the presence of multicollinearity and high leverage points. In logistic regression, multicollinearity exists among predictors and in the information matrix. The maximum likelihood estimator suffers a huge setback in the presence of multicollinearity which cause regression estimates to have unduly large standard errors. To remedy this problem, a logistic ridge regression estimator is put forward. It is evident that the logistic ridge regression estimator outperforms the maximum likelihood approach for handling multicollinearity. The effect of high leverage points are then investigated on the performance of the logistic ridge regression estimator through real data set and simulation study. The findings signify that logistic ridge regression estimator fails to provide better parameter estimates in the presence of both high leverage points and multicollinearity.

  7. Assessment of patient-specific surgery effect based on weighted estimation and propensity scoring in the re-analysis of the sciatica trial.

    PubMed

    Mertens, Bart J A; Jacobs, Wilco C H; Brand, Ronald; Peul, Wilco C

    2014-01-01

    We consider a re-analysis of the wait-and-see (control) arm of a recent clinical trial on sciatica. While the original randomised trial was designed to evaluate the public policy effect of a conservative wait-and-see approach versus early surgery, we investigate the impact of surgery at the individual patient level in a re-analysis of the wait-and-see group data. Both marginal structural model re-weighted estimates as well as propensity score adjusted analyses are presented. Results indicate that patients with high propensity to receive surgery may have beneficial effects at 2 years from delayed disc surgery.

  8. Generalizations and Extensions of the Probability of Superiority Effect Size Estimator

    ERIC Educational Resources Information Center

    Ruscio, John; Gera, Benjamin Lee

    2013-01-01

    Researchers are strongly encouraged to accompany the results of statistical tests with appropriate estimates of effect size. For 2-group comparisons, a probability-based effect size estimator ("A") has many appealing properties (e.g., it is easy to understand, robust to violations of parametric assumptions, insensitive to outliers). We review…

  9. Estimation of Nuclear Reaction Effects in Proton-Tissue-Dose Calculations.

    1983-01-14

    Version 00 REPC reviews calculational methods for the estimation of dose from external proton exposure of arbitrary convex bodies and presents the necessary information for the estimation of dose in soft tissue. The effects of nuclear reactions, especially in relation to the dose equivalent, are retained. REPC subroutines can be used to convert existing computer programs which neglect nuclear reaction effects to include them.

  10. Emotional adjustment and distressed interpersonal relations among low-income African American mothers: moderating effects of demanding kin relations.

    PubMed

    Taylor, Ronald D; Budescu, Mia

    2013-01-01

    Association of mothers' emotional adjustment and negative kin relations with distressed interpersonal relations was examined. Among 115 low-income African American mothers, relationship of depressive symptoms, self-esteem, and demanding kin relations with psychological control and stressful interpersonal relations was assessed. Depressive symptoms and demanding kin relations were positively associated with mothers' use of psychological control in parenting. Interaction of self-esteem with demanding kin relations revealed that self-esteem was negatively associated with psychological control for mothers with high-demanding kin relations but not for mothers with low-demanding kin relations. Mothers' depressive symptoms and demanding kin relations were positively associated with their stressful interpersonal relations. Findings were discussed in terms of the need for research on the beneficial and detrimental aspects of families' social network. PMID:23356357

  11. Emotional adjustment and distressed interpersonal relations among low-income African American mothers: moderating effects of demanding kin relations.

    PubMed

    Taylor, Ronald D; Budescu, Mia

    2013-01-01

    Association of mothers' emotional adjustment and negative kin relations with distressed interpersonal relations was examined. Among 115 low-income African American mothers, relationship of depressive symptoms, self-esteem, and demanding kin relations with psychological control and stressful interpersonal relations was assessed. Depressive symptoms and demanding kin relations were positively associated with mothers' use of psychological control in parenting. Interaction of self-esteem with demanding kin relations revealed that self-esteem was negatively associated with psychological control for mothers with high-demanding kin relations but not for mothers with low-demanding kin relations. Mothers' depressive symptoms and demanding kin relations were positively associated with their stressful interpersonal relations. Findings were discussed in terms of the need for research on the beneficial and detrimental aspects of families' social network.

  12. Children Use Categories to Maximize Accuracy in Estimation

    ERIC Educational Resources Information Center

    Duffy, Sean; Huttenlocher, Janellen; Crawford, L. Elizabeth

    2006-01-01

    The present study tests a model of category effects upon stimulus estimation in children. Prior work with adults suggests that people inductively generalize distributional information about a category of stimuli and use this information to adjust their estimates of individual stimuli in a way that maximizes average accuracy in estimation (see…

  13. Simultaneous estimation of effects of gender, age and walking speed on kinematic gait data.

    PubMed

    Røislien, Jo; Skare, Øivind; Gustavsen, Marit; Broch, Nana L; Rennie, Linda; Opheim, Arve

    2009-11-01

    Analysis of variations in normal gait has received considerable attention over the last years. However, most such analyses are carried out on one explanatory variable at a time, and adjustments for other possibly influencing factors are often done using ad hoc methods. As a result, it can be difficult to know whether observed effects are actually a result of the variable under study. We wanted to simultaneously statistically test the effect of gender, age and walking speed on gait in a normal population, while also properly adjusting for the possibly confounding effects of body height and weight. Since point-by-point analysis does not take into account the time dependency in the data, we turned to functional data analysis (FDA). In FDA the whole gait curve is represented not by a set of points, but by a mathematical function spanning the whole gait cycle. We performed several multiple functional regression analyses, and the results indicate that walking speed is the main factor influencing gait in the reference material at our motion analysis laboratory. This effect is also largely unaffected by the presence of other variables in the model. A gender effect was also apparent in several planes and joints, but this effect was often more outspoken in the multiple than in the univariate regression analyses, highlighting the importance of adjusting for confounders like body height and weight.

  14. The effectiveness of tape playbacks in estimating Black Rail densities

    USGS Publications Warehouse

    Legare, M.; Eddleman, W.R.; Buckley, P.A.; Kelly, C.

    1999-01-01

    Tape playback is often the only efficient technique to survey for secretive birds. We measured the vocal responses and movements of radio-tagged black rails (Laterallus jamaicensis; 26 M, 17 F) to playback of vocalizations at 2 sites in Florida during the breeding seasons of 1992-95. We used coefficients from logistic regression equations to model probability of a response conditional to the birds' sex. nesting status, distance to playback source, and time of survey. With a probability of 0.811, nonnesting male black rails were ))lost likely to respond to playback, while nesting females were the least likely to respond (probability = 0.189). We used linear regression to determine daily, monthly and annual variation in response from weekly playback surveys along a fixed route during the breeding seasons of 1993-95. Significant sources of variation in the regression model were month (F3.48 = 3.89, P = 0.014), year (F2.48 = 9.37, P < 0.001), temperature (F1.48 = 5.44, P = 0.024), and month X year (F5.48 = 2.69, P = 0.031). The model was highly significant (P < 0.001) and explained 54% of the variation of mean response per survey period (r2 = 0.54). We combined response probability data from radiotagged black rails with playback survey route data to provide a density estimate of 0.25 birds/ha for the St. Johns National Wildlife Refuge. The relation between the number of black rails heard during playback surveys to the actual number present was influenced by a number of variables. We recommend caution when making density estimates from tape playback surveys

  15. Estimates of epistatic and pleiotropic effects of () and () genetic markers on beef heifer performance traits enhanced by selection.

    PubMed

    Tait, R G; Cushman, R A; McNeel, A K; Casas, E; Smith, T P L; Freetly, H C; Bennett, G L

    2016-03-01

    Genetic marker effects and type of inheritance are estimated with poor precision when minor marker allele frequencies are low. A stable composite population (MARC II) was subjected to marker assisted selection for 2 yr to equalize and genetic marker frequencies to evaluate the epistatic and pleiotropic effects of these markers on BW, reproduction, and first calf performance traits in replacement beef females ( = 171) managed under 2 postweaning development protocols. Traits evaluated on the heifers were birth BW, weaning BW, 11-mo BW, 12-mo BW, 13-mo BW, first breeding season pregnancy evaluation BW, first calving season BW, 11-mo puberty, 12-mo puberty, 13-mo puberty, first breeding season pregnancy, and first calf weaning rate. Additionally, heifer's first calf performance traits of ordinal calving date, first calf birth BW, and first calf weaning BW (with and without age adjustment) were analyzed. Selection to increase minor allele frequencies and balanced sampling across genotype classes enhanced the ability to detect all genetic effects except dominance × dominance epistasis. The × genotype effect was significant ( < 0.05) for 11-mo BW and 12-mo BW and tended to be significant ( = 0.08) for 13-mo BW. Consistently, for all 3 traits, the most significant effect among epistatic × genotype effects was the additive effect, with the G allele decreasing BW. There were no associations between × genotype and fertility related traits ( ≥ 0.46) in this study. Additionally, there were no × genotype associations with first progeny performance traits ( ≥ 0.14). The large effect of the additive × additive interaction on first calf weaning BW was imprecisely estimated, which may warrant further investigation. PMID:27065254

  16. School Processes Mediate School Compositional Effects: Model Specification and Estimation

    ERIC Educational Resources Information Center

    Liu, Hongqiang; Van Damme, Jan; Gielen, Sarah; Van Den Noortgate, Wim

    2015-01-01

    School composition effects have been consistently verified, but few studies ever attempted to study how school composition affects school achievement. Based on prior research findings, we employed multilevel mediation modeling to examine whether school processes mediate the effect of school composition upon school outcomes based on the data of 28…

  17. Estimating Causal Effects from Multilevel Group-Allocation Data

    ERIC Educational Resources Information Center

    Gitelman, Alix I.

    2005-01-01

    In group-allocation studies for comparing behavioral, social, or educational interventions, subjects in the same group necessarily receive the same treatment, whereby a group and/or group-dynamic effect can confound the treatment effect. General counterfactual outcomes that depend on group characteristics, group membership, and treatment are…

  18. Assessing Mediational Models: Testing and Interval Estimation for Indirect Effects

    ERIC Educational Resources Information Center

    Biesanz, Jeremy C.; Falk, Carl F.; Savalei, Victoria

    2010-01-01

    Theoretical models specifying indirect or mediated effects are common in the social sciences. An indirect effect exists when an independent variable's influence on the dependent variable is mediated through an intervening variable. Classic approaches to assessing such mediational hypotheses (Baron & Kenny, 1986; Sobel, 1982) have in recent years…

  19. The effects of sample scheduling and sample numbers on estimates of the annual fluxes of suspended sediment in fluvial systems

    USGS Publications Warehouse

    Horowitz, Arthur J.; Clarke, Robin T.; Merten, Gustavo Henrique

    2015-01-01

    Since the 1970s, there has been both continuing and growing interest in developing accurate estimates of the annual fluvial transport (fluxes and loads) of suspended sediment and sediment-associated chemical constituents. This study provides an evaluation of the effects of manual sample numbers (from 4 to 12 year−1) and sample scheduling (random-based, calendar-based and hydrology-based) on the precision, bias and accuracy of annual suspended sediment flux estimates. The evaluation is based on data from selected US Geological Survey daily suspended sediment stations in the USA and covers basins ranging in area from just over 900 km2 to nearly 2 million km2 and annual suspended sediment fluxes ranging from about 4 Kt year−1 to about 200 Mt year−1. The results appear to indicate that there is a scale effect for random-based and calendar-based sampling schemes, with larger sample numbers required as basin size decreases. All the sampling schemes evaluated display some level of positive (overestimates) or negative (underestimates) bias. The study further indicates that hydrology-based sampling schemes are likely to generate the most accurate annual suspended sediment flux estimates with the fewest number of samples, regardless of basin size. This type of scheme seems most appropriate when the determination of suspended sediment concentrations, sediment-associated chemical concentrations, annual suspended sediment and annual suspended sediment-associated chemical fluxes only represent a few of the parameters of interest in multidisciplinary, multiparameter monitoring programmes. The results are just as applicable to the calibration of autosamplers/suspended sediment surrogates currently used to measure/estimate suspended sediment concentrations and ultimately, annual suspended sediment fluxes, because manual samples are required to adjust the sample data/measurements generated by these techniques so that they provide depth-integrated and cross

  20. Adjustable hydrazine modulation of single-wall carbon nanotube network field effect transistors from p-type to n-type

    NASA Astrophysics Data System (ADS)

    Dai, Ruixuan; Xie, Dan; Xu, Jianlong; Sun, Yilin; Sun, MengXing; Zhang, Cheng; Li, Xian

    2016-11-01

    Single-wall carbon nanotube (SWCNT) network field effect transistors (FETs), which show decent p-type electronic properties, have been fabricated. The use of hydrazine as an aqueous solution and a strong n-type dopant for the SWCNTs is demonstrated in this paper. The electrical properties are obviously tuned by hydrazine treatment at different concentrations on the surface of the SWCNT network FETs. The transport behavior of SWCNTs can be modulated from p-type to n-type, demonstrating the controllable and adjustable doping effect of hydrazine. With a higher concentration of hydrazine, more electrons can be transferred from the hydrazine molecules to the SWCNT network films, thus resulting in a change of threshold voltage, carrier mobility and on-current. By cleaning the device, the hydrazine doping effects vanish, which indicates that the doping effects of hydrazine are reversible. Through x-ray photoelectron spectroscopy (XPS) characterization, the doping effects of hydrazine have also been studied.

  1. Adjustable hydrazine modulation of single-wall carbon nanotube network field effect transistors from p-type to n-type.

    PubMed

    Dai, Ruixuan; Xie, Dan; Xu, Jianlong; Sun, Yilin; Sun, MengXing; Zhang, Cheng; Li, Xian

    2016-11-01

    Single-wall carbon nanotube (SWCNT) network field effect transistors (FETs), which show decent p-type electronic properties, have been fabricated. The use of hydrazine as an aqueous solution and a strong n-type dopant for the SWCNTs is demonstrated in this paper. The electrical properties are obviously tuned by hydrazine treatment at different concentrations on the surface of the SWCNT network FETs. The transport behavior of SWCNTs can be modulated from p-type to n-type, demonstrating the controllable and adjustable doping effect of hydrazine. With a higher concentration of hydrazine, more electrons can be transferred from the hydrazine molecules to the SWCNT network films, thus resulting in a change of threshold voltage, carrier mobility and on-current. By cleaning the device, the hydrazine doping effects vanish, which indicates that the doping effects of hydrazine are reversible. Through x-ray photoelectron spectroscopy (XPS) characterization, the doping effects of hydrazine have also been studied.

  2. Adjustable hydrazine modulation of single-wall carbon nanotube network field effect transistors from p-type to n-type.

    PubMed

    Dai, Ruixuan; Xie, Dan; Xu, Jianlong; Sun, Yilin; Sun, MengXing; Zhang, Cheng; Li, Xian

    2016-11-01

    Single-wall carbon nanotube (SWCNT) network field effect transistors (FETs), which show decent p-type electronic properties, have been fabricated. The use of hydrazine as an aqueous solution and a strong n-type dopant for the SWCNTs is demonstrated in this paper. The electrical properties are obviously tuned by hydrazine treatment at different concentrations on the surface of the SWCNT network FETs. The transport behavior of SWCNTs can be modulated from p-type to n-type, demonstrating the controllable and adjustable doping effect of hydrazine. With a higher concentration of hydrazine, more electrons can be transferred from the hydrazine molecules to the SWCNT network films, thus resulting in a change of threshold voltage, carrier mobility and on-current. By cleaning the device, the hydrazine doping effects vanish, which indicates that the doping effects of hydrazine are reversible. Through x-ray photoelectron spectroscopy (XPS) characterization, the doping effects of hydrazine have also been studied. PMID:27670730

  3. Visualizing spatial population structure with estimated effective migration surfaces.

    PubMed

    Petkova, Desislava; Novembre, John; Stephens, Matthew

    2016-01-01

    Genetic data often exhibit patterns broadly consistent with 'isolation by distance'-a phenomenon where genetic similarity decays with geographic distance. In a heterogeneous habitat, this may occur more quickly in some regions than in others: for example, barriers to gene flow can accelerate differentiation between neighboring groups. We use the concept of 'effective migration' to model the relationship between genetics and geography. In this paradigm, effective migration is low in regions where genetic similarity decays quickly. We present a method to visualize variation in effective migration across a habitat from geographically indexed genetic data. Our approach uses a population genetic model to relate effective migration rates to expected genetic dissimilarities. We illustrate its potential and limitations using simulations and data from elephant, human and Arabidopsis thaliana populations. The resulting visualizations highlight important spatial features of population structure that are difficult to discern using existing methods for summarizing genetic variation.

  4. Estimated ecological effects of triazine use of surface waters

    SciTech Connect

    Mercurio, S.D.

    1996-10-01

    Based on the current intensive use of triazines in agriculture in the northern portions of the Midwest, ecological impacts have been evaluated in surface waters. Considerations from application methods to stream concentrations predict a range of impacts using current toxicity models. Standard {open_quotes}static{close_quotes} LC{sub 50}s predict only algal mortality at peak runoff, while laboratory flow-through systems indicate seasonal impacts on primary stream productivity. Mesocosms further observe indirect effects on numerous species during the year. Microcosm and flow-through wetland mesocosm studies indicate primary effects during the growing season on algal populations, magnified by zooplankton bloom stresses and indirect effects on dissolved oxygen and nutrient concentrations. If the river continuum model is considered in combination with triazine concentrations, clear untoward effects on stream ecosystems occur with current practices. The use of banding application or other remediation techniques for positive ecological and economic gains as proven alternatives to current uses are encouraged.

  5. Visualizing spatial population structure with estimated effective migration surfaces

    PubMed Central

    Petkova, Desislava; Novembre, John; Stephens, Matthew

    2015-01-01

    Genetic data often exhibit patterns broadly consistent with “isolation by distance” – a phenomenon where genetic similarity decays with geographic distance. In a heterogeneous habitat this may occur more quickly in some regions than others: for example, barriers to gene flow can accelerate differentiation between neighboring groups. We use the concept of “effective migration” to model the relationship between genetics and geography: in this paradigm, effective migration is low in regions where genetic similarity decays quickly. We present a method to visualize variation in effective migration across the habitat from geographically indexed genetic data. Our approach uses a population genetic model to relate effective migration rates to expected genetic dissimilarities. We illustrate its potential and limitations using simulations and data from elephant, human and A. thaliana populations. The resulting visualizations highlight important spatial features of population structure that are difficult to discern using existing methods for summarizing genetic variation. PMID:26642242

  6. Handbook for the estimation of microwave propagation effects: Link calculations for earth-space paths (path loss and noise estimation)

    NASA Technical Reports Server (NTRS)

    Crane, R. K.; Blood, D. W.

    1979-01-01

    A single model for a standard of comparison for other models when dealing with rain attenuation problems in system design and experimentation is proposed. Refinements to the Global Rain Production Model are incorporated. Path loss and noise estimation procedures as the basic input to systems design for earth-to-space microwave links operating at frequencies from 1 to 300 GHz are provided. Topics covered include gaseous absorption, attenuation by rain, ionospheric and tropospheric scintillation, low elevation angle effects, radome attenuation, diversity schemes, link calculation, and receiver noise emission by atmospheric gases, rain, and antenna contributions.

  7. Simple Estimation of Patient-Oriented Effects From Randomized Trials: An Open and Shut CACE.

    PubMed

    Steele, Russell J; Shrier, Ian; Kaufman, Jay S; Platt, Robert W

    2015-09-15

    In randomized controlled trials, the intention-to-treat estimator provides an unbiased estimate of the causal effect of treatment assignment on the outcome. However, patients often want to know what the effect would be if they were to take the treatment as prescribed (the patient-oriented effect), and several researchers have suggested that the more relevant causal effect for this question is the complier average causal effect (CACE), also referred to as the local average treatment effect. Sophisticated approaches to estimating the CACE include Bayesian and frequentist methods for principal stratification, inverse-probability-of-treatment-weighted estimators, and instrumental-variable (IV) analysis. All of these approaches exploit information about adherence to assigned treatment to improve upon the intention-to-treat estimator, but they are rarely used in practice, probably because of their complexity. The IV principal stratification estimator is simple to implement but has had limited use in practice, possibly due to lack of familiarity. Here, we show that the IV principal stratification estimator is a modified per-protocol estimator that should be obtainable from any randomized controlled trial, and we provide a closed form for its robust variance (and its uncertainty). Finally, we illustrate sensitivity analyses we conducted to assess inference in light of potential violations of the exclusion restriction assumption.

  8. Human-machine teaming for effective estimation and path planning

    NASA Astrophysics Data System (ADS)

    McCourt, Michael J.; Mehta, Siddhartha S.; Doucette, Emily A.; Curtis, J. Willard

    2016-05-01

    While traditional sensors provide accurate measurements of quantifiable information, humans provide better qualitative information and holistic assessments. Sensor fusion approaches that team humans and machines can take advantage of the benefits provided by each while mitigating the shortcomings. These two sensor sources can be fused together using Bayesian fusion, which assumes that there is a method of generating a probabilistic representation of the sensor measurement. This general framework of fusing estimates can also be applied to joint human-machine decision making. In the simple case, binary decisions can be fused by using a probability of taking an action versus inaction from each decision-making source. These are fused together to arrive at a final probability of taking an action, which would be taken if above a specified threshold. In the case of path planning, rather than binary decisions being fused, complex decisions can be fused by allowing the human and machine to interact with each other. For example, the human can draw a suggested path while the machine planning algorithm can refine it to avoid obstacles and remain dynamically feasible. Similarly, the human can revise a suggested path to achieve secondary goals not encoded in the algorithm such as avoiding dangerous areas in the environment.

  9. Optimizing matching and analysis combinations for estimating causal effects

    NASA Astrophysics Data System (ADS)

    Colson, K. Ellicott; Rudolph, Kara E.; Zimmerman, Scott C.; Goin, Dana E.; Stuart, Elizabeth A.; Laan, Mark Van Der; Ahern, Jennifer

    2016-03-01

    Matching methods are common in studies across many disciplines. However, there is limited evidence on how to optimally combine matching with subsequent analysis approaches to minimize bias and maximize efficiency for the quantity of interest. We conducted simulations to compare the performance of a wide variety of matching methods and analysis approaches in terms of bias, variance, and mean squared error (MSE). We then compared these approaches in an applied example of an employment training program. The results indicate that combining full matching with double robust analysis performed best in both the simulations and the applied example, particularly when combined with machine learning estimation methods. To reduce bias, current guidelines advise researchers to select the technique with the best post-matching covariate balance, but this work finds that such an approach does not always minimize mean squared error (MSE). These findings have important implications for future research utilizing matching. To minimize MSE, investigators should consider additional diagnostics, and use of simulations tailored to the study of interest to identify the optimal matching and analysis combination.

  10. Optimizing matching and analysis combinations for estimating causal effects

    PubMed Central

    Colson, K. Ellicott; Rudolph, Kara E.; Zimmerman, Scott C.; Goin, Dana E.; Stuart, Elizabeth A.; Laan, Mark van der; Ahern, Jennifer

    2016-01-01

    Matching methods are common in studies across many disciplines. However, there is limited evidence on how to optimally combine matching with subsequent analysis approaches to minimize bias and maximize efficiency for the quantity of interest. We conducted simulations to compare the performance of a wide variety of matching methods and analysis approaches in terms of bias, variance, and mean squared error (MSE). We then compared these approaches in an applied example of an employment training program. The results indicate that combining full matching with double robust analysis performed best in both the simulations and the applied example, particularly when combined with machine learning estimation methods. To reduce bias, current guidelines advise researchers to select the technique with the best post-matching covariate balance, but this work finds that such an approach does not always minimize mean squared error (MSE). These findings have important implications for future research utilizing matching. To minimize MSE, investigators should consider additional diagnostics, and use of simulations tailored to the study of interest to identify the optimal matching and analysis combination. PMID:26980444

  11. Potential effects of translatory waves on estimation of peak flows

    USGS Publications Warehouse

    Hjalmarson, H.W.; Phillips, J.V.

    1997-01-01

    During the afternoon of August 19, 1971, an intense thunderstorm a few miles southwest of Wikieup, Arizona, produced one of the largest known flood peaks for a 49.2-square-km drainage basin. Initial computations of the peak discharge assumed stable flow conditions and a four-section slope area measurement indicated that discharge was 2,082 m3/s. Recent findings based on free-surface instability characteristics at the site suggest that gravitational forces exceeded boundary retarding forces, and flow in the wide sand channel was unstable. Computations for roll or translatory waves indicate that waves crashed into the highway bridge at velocities of as much as 12.5 m/s. The close agreement of free surface instability results, translatory wave computations, estimates of the steady flow on which the translatory waves traveled, and an eyewitness account of the translatory waves suggest the total peak discharge could have been 2,742 m3/s or 32% greater than the published discharge. The occurrence of translatory waves in natural channels may be more common than previously thought, and instability criteria should be considered for hydraulic analysis of flow in steep smooth channels.

  12. Estimates of effects of residual acceleration on USML-1 experiments

    NASA Technical Reports Server (NTRS)

    Naumann, Robert J.

    1995-01-01

    The purpose of this study effort was to develop analytical models to describe the effects of residual accelerations on the experiments to be carried on the first U.S. Microgravity Lab mission (USML-1) and to test the accuracy of these models by comparing the pre-flight predicted effects with the post-flight measured effects. After surveying the experiments to be performed on USML-1, it became evident that the anticipated residual accelerations during the USML-1 mission were well below the threshold for most of the primary experiments and all of the secondary (Glovebox) experiments and that the only set of experiments that could provide quantifiable effects, and thus provide a definitive test of the analytical models, were the three melt growth experiments using the Bridgman-Stockbarger type Crystal Growth Furnace (CGF). This class of experiments is by far the most sensitive to low level quasi-steady accelerations that are unavoidable on space craft operating in low earth orbit. Because of this, they have been the drivers for the acceleration requirements imposed on the Space Station. Therefore, it is appropriate that the models on which these requirements are based are tested experimentally. Also, since solidification proceeds directionally over a long period of time, the solidified ingot provides a more or less continuous record of the effects from acceleration disturbances.

  13. Risk adjustment for high utilizers of public mental health care.

    PubMed

    Kapur, Kanika; Young, Alexander S.; Murata, Dennis

    2000-09-01

    evidence that the disenrollment from the pilot capitation initiative input have been reduced if risk adjustment had been used to set capitation rates. DISCUSSION: The evidence suggests that even though risk adjustment techniques have room to improve, they are still likely to be useful for reducing risk selection in capitation programs. Blended payment schemes that combine risk adjustment with risk corridors or partial fee-for-service payments should be explored. IMPLICATIONS FOR HEALTH CARE PROVISION, USE, AND POLICY: Our results suggest that risk adjustment methods, as developed to data, do not have the requisite predictive power to be used as the sole approach to adjusting capitation rates. Risk adjustment is informative and useful; however, payments to providers should not be fully capitated, and may need to involve some degree of risk sharing between providers and public mental health agencies. A blended contract design may further reduce incentives for risk selection by incorporating a partly risk-adjusted capitation payment, without relying completely on the accuracy of risk adjustment models. IMPLICATIONS FOR FURTHER RESEARCH: Risk adjustment models estimated using data sets containing better predictors of rehospitalization and more precise clinical information are likely to have higher predictive power. Further research should also focus on the effect of combination contract designs. PMID:11967448

  14. Maternal adjustment or constraint: differential effects of food availability on maternal deposition of macro-nutrients, steroids and thyroid hormones in rock pigeon eggs.

    PubMed

    Hsu, Bin-Yan; Dijkstra, Cor; Darras, Veerle M; de Vries, Bonnie; Groothuis, Ton G G

    2016-01-01

    In oviparous species like birds, eggs provide the direct environment in which embryos are developing. Mothers may adjust different egg components in different ways in reaction to environmental cues either to adjust offspring development or because of constraints. In this study, we investigated the effects of food quality and quantity before and during egg laying on three different aspects of egg quality: macro-nutrients (egg and yolk mass), androgens (testosterone and androstenedione), and thyroid hormones (3,5,3'-triiodothyronine, T3 and l-thyroxine, T4), using the rock pigeon (Columba livia). As expected, egg and yolk mass were significantly reduced for the eggs laid under the poor-food condition, indicating a maternal trade-off between offspring and self in allocating important resources. We did not find any significant change in yolk testosterone or their within-clutch pattern over the laying sequence. This is consistent with the fact that, in contrast with nutrients, these hormones are not costly to produce, but does not support the hypothesis that they play a role in adjusting brood size to food conditions. In contrast, we found that T3 levels were higher in the egg yolks under the poor-food condition whereas the total T4 content was lower. This change could be related to the fact that iodine, the critical constituent of thyroid hormones, might be a limiting factor in the production of this hormone. Given the knowledge that food restriction usually lead to reduction of circulating T3 levels, our results suggested that avian mothers can independently regulate its concentrations in their eggs from their own circulation. The study demonstrates that environmentally induced maternal effects via the egg can be a result of a combination of constrained resources and unconstrained signals and that thyroid hormones might be an interesting case of both. Therefore, this hormone and the interplay of different maternal effects on the offspring phenotype deserve much more

  15. Synthesis gas production with an adjustable H{sub 2}/CO ratio through the coal gasification process: effects of coal ranks and methane addition

    SciTech Connect

    Yan Cao; Zhengyang Gao; Jing Jin; Hongchang Zhou; Marten Cohron; Houying Zhao; Hongying Liu; Weiping Pan

    2008-05-15

    Direct production of synthesis gas using coal as a cheap feedstock is attractive but challenging due to its low H{sub 2}/CO ratio of generated synthesis gas. Three typical U.S. coals of different ranks were tested in a 2.5 in. coal gasifier to investigate their gasification reactivity and adjustability on H{sub 2}/CO ratio of generated synthesis gas with or without the addition of methane. Tests indicated that lower-rank coals (lignite and sub-bituminous) have higher gasification reactivity than bituminous coals. The coal gasification reactivity is correlated to its synthesis-gas yield and the total percentage of H{sub 2} and CO in the synthesis gas, but not to the H{sub 2}/CO ratio. The H{sub 2}/CO ratio of coal gasification was found to be correlated to the rank of coals, especially the H/C ratio of coals. Methane addition into the dense phase of the pyrolysis and gasification zone of the cogasification reactor could make the best use of methane in adjusting the H{sub 2}/CO ratio of the generated synthesis gas. The maximum methane conversion efficiency, which was likely correlated to its gasification reactivity, could be achieved by 70% on average for all tested coals. The actual catalytic effect of generated coal chars on methane conversion seemed coal-dependent. The coal-gasification process benefits from methane addition and subsequent conversion on the adjustment of the H{sub 2}/CO ratio of synthesis gas. The methane conversion process benefits from the use of coal chars due to their catalytic effects. This implies that there were likely synergistic effects on both. 25 refs., 3 figs., 3

  16. Maternal adjustment or constraint: differential effects of food availability on maternal deposition of macro-nutrients, steroids and thyroid hormones in rock pigeon eggs.

    PubMed

    Hsu, Bin-Yan; Dijkstra, Cor; Darras, Veerle M; de Vries, Bonnie; Groothuis, Ton G G

    2016-01-01

    In oviparous species like birds, eggs provide the direct environment in which embryos are developing. Mothers may adjust different egg components in different ways in reaction to environmental cues either to adjust offspring development or because of constraints. In this study, we investigated the effects of food quality and quantity before and during egg laying on three different aspects of egg quality: macro-nutrients (egg and yolk mass), androgens (testosterone and androstenedione), and thyroid hormones (3,5,3'-triiodothyronine, T3 and l-thyroxine, T4), using the rock pigeon (Columba livia). As expected, egg and yolk mass were significantly reduced for the eggs laid under the poor-food condition, indicating a maternal trade-off between offspring and self in allocating important resources. We did not find any significant change in yolk testosterone or their within-clutch pattern over the laying sequence. This is consistent with the fact that, in contrast with nutrients, these hormones are not costly to produce, but does not support the hypothesis that they play a role in adjusting brood size to food conditions. In contrast, we found that T3 levels were higher in the egg yolks under the poor-food condition whereas the total T4 content was lower. This change could be related to the fact that iodine, the critical constituent of thyroid hormones, might be a limiting factor in the production of this hormone. Given the knowledge that food restriction usually lead to reduction of circulating T3 levels, our results suggested that avian mothers can independently regulate its concentrations in their eggs from their own circulation. The study demonstrates that environmentally induced maternal effects via the egg can be a result of a combination of constrained resources and unconstrained signals and that thyroid hormones might be an interesting case of both. Therefore, this hormone and the interplay of different maternal effects on the offspring phenotype deserve much more

  17. Estimation of overall equipment effectiveness using simulation programme

    NASA Astrophysics Data System (ADS)

    Paprocka, I.; Kempa, W.; Kalinowski, K.; Grabowik, C.

    2015-11-01

    A queuing system of the M/M/1/N type with cyclic failure-free and repair times and cyclic defective production is used as a model of a single machine production system. Production tasks arrive according to an exponential process and are served with normally disturbed processing time. Successive working (failure-free) times, repair times and defect-free production have exponential distributions. Defective products can be recirculated and back to the production line according to a Bernoulli distributions. The objective is to evaluate effectiveness of the production system using Overall Equipment Effectiveness before and after introducing improvement initiatives.

  18. SAR image effects on coherence and coherence estimation.

    SciTech Connect

    Bickel, Douglas Lloyd

    2014-01-01

    Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

  19. Estimating volumes of the pituitary gland from T1-weighted magnetic-resonance images: effects of age, puberty, testosterone, and estradiol.

    PubMed

    Wong, Angelita Pui-Yee; Pipitone, Jon; Park, Min Tae M; Dickie, Erin W; Leonard, Gabriel; Perron, Michel; Pike, Bruce G; Richer, Louis; Veillette, Suzanne; Chakravarty, M Mallar; Pausova, Zdenka; Paus, Tomáš

    2014-07-01

    The pituitary gland is a key structure in the hypothalamic-pituitary-gonadal (HPG) axis--it plays an important role in sexual maturation during puberty. Despite its small size, its volume can be quantified using magnetic resonance imaging (MRI). Here, we study a cohort of 962 typically developing adolescents from the Saguenay Youth Study and estimate pituitary volumes using a newly developed multi-atlas segmentation method known as the MAGeT Brain algorithm. We found that age and puberty stage (controlled for age) each predicts adjusted pituitary volumes (controlled for total brain volume) in both males and females. Controlling for the effects of age and puberty stage, total testosterone and estradiol levels also predict adjusted pituitary volumes in males and pre-menarche females, respectively. These findings demonstrate that the pituitary gland grows during adolescence, and its volume relates to circulating plasma-levels of sex steroids in both males and females.

  20. On the Importance of Reliable Covariate Measurement in Selection Bias Adjustments Using Propensity Scores

    ERIC Educational Resources Information Center

    Steiner, Peter M.; Cook, Thomas D.; Shadish, William R.

    2011-01-01

    The effect of unreliability of measurement on propensity score (PS) adjusted treatment effects has not been previously studied. The authors report on a study simulating different degrees of unreliability in the multiple covariates that were used to estimate the PS. The simulation uses the same data as two prior studies. Shadish, Clark, and Steiner…