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Sample records for parametric competing risks

  1. Parametric likelihood inference for interval censored competing risks data

    PubMed Central

    Hudgens, Michael G.; Li, Chenxi

    2014-01-01

    Summary Parametric estimation of the cumulative incidence function (CIF) is considered for competing risks data subject to interval censoring. Existing parametric models of the CIF for right censored competing risks data are adapted to the general case of interval censoring. Maximum likelihood estimators for the CIF are considered under the assumed models, extending earlier work on nonparametric estimation. A simple naive likelihood estimator is also considered that utilizes only part of the observed data. The naive estimator enables separate estimation of models for each cause, unlike full maximum likelihood in which all models are fit simultaneously. The naive likelihood is shown to be valid under mixed case interval censoring, but not under an independent inspection process model, in contrast with full maximum likelihood which is valid under both interval censoring models. In simulations, the naive estimator is shown to perform well and yield comparable efficiency to the full likelihood estimator in some settings. The methods are applied to data from a large, recent randomized clinical trial for the prevention of mother-to-child transmission of HIV. PMID:24400873

  2. Parametric Estimation in a Recurrent Competing Risks Model

    PubMed Central

    Peña, Edsel A.

    2014-01-01

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

  3. Bayesian Semi-parametric Analysis of Semi-competing Risks Data: Investigating Hospital Readmission after a Pancreatic Cancer Diagnosis

    PubMed Central

    Lee, Kyu Ha; Haneuse, Sebastien; Schrag, Deborah; Dominici, Francesca

    2014-01-01

    Summary In the U.S., the Centers for Medicare and Medicaid Services uses 30-day readmission, following hospitalization, as a proxy outcome to monitor quality of care. These efforts generally focus on treatable health conditions, such as pneumonia and heart failure. Expanding quality of care systems to monitor conditions for which treatment options are limited or non-existent, such as pancreatic cancer, is challenging because of the non-trivial force of mortality; 30-day mortality for pancreatic cancer is approximately 30%. In the statistical literature, data that arise when the observation of the time to some non-terminal event is subject to some terminal event are referred to as ‘semi-competing risks data’. Given such data, scientific interest may lie in at least one of three areas: (i) estimation/inference for regression parameters, (ii) characterization of dependence between the two events, and (iii) prediction given a covariate profile. Existing statistical methods focus almost exclusively on the first of these; methods are sparse or non-existent, however, when interest lies with understanding dependence and performing prediction. In this paper we propose a Bayesian semi-parametric regression framework for analyzing semi-competing risks data that permits the simultaneous investigation of all three of the aforementioned scientific goals. Characterization of the induced posterior and posterior predictive distributions is achieved via an efficient Metropolis-Hastings-Green algorithm, which has been implemented in an R package. The proposed framework is applied to data on 16,051 individuals diagnosed with pancreatic cancer between 2005-2008, obtained from Medicare Part A. We found that increased risk for readmission is associated with a high comorbidity index, a long hospital stay at initial hospitalization, non-white race, male, and discharge to home care. PMID:25977592

  4. Recursive Partitioning Method on Competing Risk Outcomes

    PubMed Central

    Xu, Wei; Che, Jiahua; Kong, Qin

    2016-01-01

    In some cancer clinical studies, researchers have interests to explore the risk factors associated with competing risk outcomes such as recurrence-free survival. We develop a novel recursive partitioning framework on competing risk data for both prognostic and predictive model constructions. We define specific splitting rules, pruning algorithm, and final tree selection algorithm for the competing risk tree models. This methodology is quite flexible that it can corporate both semiparametric method using Cox proportional hazards model and parametric competing risk model. Both prognostic and predictive tree models are developed to adjust for potential confounding factors. Extensive simulations show that our methods have well-controlled type I error and robust power performance. Finally, we apply both Cox proportional hazards model and flexible parametric model for prognostic tree development on a retrospective clinical study on oropharyngeal cancer patients. PMID:27486300

  5. Recursive Partitioning Method on Competing Risk Outcomes.

    PubMed

    Xu, Wei; Che, Jiahua; Kong, Qin

    2016-01-01

    In some cancer clinical studies, researchers have interests to explore the risk factors associated with competing risk outcomes such as recurrence-free survival. We develop a novel recursive partitioning framework on competing risk data for both prognostic and predictive model constructions. We define specific splitting rules, pruning algorithm, and final tree selection algorithm for the competing risk tree models. This methodology is quite flexible that it can corporate both semiparametric method using Cox proportional hazards model and parametric competing risk model. Both prognostic and predictive tree models are developed to adjust for potential confounding factors. Extensive simulations show that our methods have well-controlled type I error and robust power performance. Finally, we apply both Cox proportional hazards model and flexible parametric model for prognostic tree development on a retrospective clinical study on oropharyngeal cancer patients. PMID:27486300

  6. Direct likelihood inference and sensitivity analysis for competing risks regression with missing causes of failure.

    PubMed

    Moreno-Betancur, Margarita; Rey, Grégoire; Latouche, Aurélien

    2015-06-01

    Competing risks arise in the analysis of failure times when there is a distinction between different causes of failure. In many studies, it is difficult to obtain complete cause of failure information for all individuals. Thus, several authors have proposed strategies for semi-parametric modeling of competing risks when some causes of failure are missing under the missing at random (MAR) assumption. As many authors have stressed, while semi-parametric models are convenient, fully-parametric regression modeling of the cause-specific hazards (CSH) and cumulative incidence functions (CIF) may be of interest for prediction and is likely to contribute towards a fuller understanding of the time-dynamics of the competing risks mechanism. We propose a so-called "direct likelihood" approach for fitting fully-parametric regression models for these two functionals under MAR. The MAR assumption not being verifiable from the observed data, we propose an approach for performing sensitivity analyses to assess the robustness of inferences to departures from this assumption. The method relies on so-called "pattern-mixture models" from the missing data literature and was evaluated in a simulation study. This sensitivity analysis approach is applicable to various competing risks regression models (fully-parametric or semi-parametric, for the CSH or the CIF). We illustrate the proposed methods with the analysis of a breast cancer clinical trial, including suggestions for ad hoc graphical goodness-of-fit assessments under MAR.

  7. Familial Risk and Child Competence.

    ERIC Educational Resources Information Center

    Sameroff, Arnold J.; Seifer, Ronald

    1983-01-01

    Examines components of familial risk in the context of a four-year longitudinal study of children with mentally ill mothers. Risk factors examined were parental mental health, social status, parental perspectives, and family stress. Interactions among risk factors were found to be complex and different for cognitive and social-emotional…

  8. Creating Efficient Instrumentation Networks to Support Parametric Risk Transfer

    NASA Astrophysics Data System (ADS)

    Rockett, P.

    2009-04-01

    The development and institutionalisation of Catastrophe modelling during the 1990s opened the way for Catastrophe risk securitization transactions in which catastrophe risk held by insurers is transferred to the capital markets in the form of a bond. Cat Bonds have been one of the few areas of the capital markets in which the risk modelling has remained secure and the returns on the bonds have held up well through the 2008 Credit Crunch. There are three ways of structuring the loss triggers on bonds: ‘indemnity triggers' - reflecting the actual losses to the issuers; ‘index triggers' reflecting the losses to some index such as reported insurance industry loss and ‘parametric triggers' reflecting the parameters of the underlying catastrophe event itself. Indemnity triggers require that the investors trust that the insurer is reporting all their underlying exposures, while both indemnity and index losses may take 1-2 years to settle before all the claims are reported and resolved. Therefore parametric structures have many advantages, in particular in that the bond can be settled rapidly after an event. The challenge is to create parametric indices that closely reflect the actual losses to the insurer - ie that minimise ‘basis risk'. First generation parametric indices had high basis risk as they were crudely based on the magnitude of an earthquake occurring within some defined geographical box, or the intensity of a hurricane relative to the distance of the storm from some location. Second generation triggers involve taking measurements of ground motion or windspeed or flood depths at many locations and weighting each value so that the overall index closely mimics insurance loss. Cat bonds with second generation parametric triggers have been successfully issued for European Windstorm, UK Flood and California and Japan Earthquake. However the spread of second generation parametric structures is limited by the availability of suitable networks of

  9. Risks, risk assessment and risk competence in toxicology

    PubMed Central

    Stahlmann, Ralf; Horvath, Aniko

    2015-01-01

    Understanding the toxic effects of xenobiotics requires sound knowledge of physiology and biochemistry. The often described lack of understanding pharmacology/toxicology is therefore primarily caused by the general absence of the necessary fundamental knowledge. Since toxic effects depend on exposure (or dosage) assessing the risks arising from toxic substances also requires quantitative reasoning. Typically public discussions nearly always neglect quantitative aspects and laypersons tend to disregard dose-effect-relationships. One of the main reasons for such disregard is the fact that exposures often occur at extremely low concentrations that can only be perceived intellectually but not by the human senses. However, thresholds in the low exposure range are often scientifically disputed. At the same time, ignorance towards known dangers is wide-spread. Thus, enhancing the risk competence of laypersons will have to be initially restricted to increasing the awareness of existing problems. PMID:26195922

  10. Minimization of Basis Risk in Parametric Earthquake Cat Bonds

    NASA Astrophysics Data System (ADS)

    Franco, G.

    2009-12-01

    A catastrophe -cat- bond is an instrument used by insurance and reinsurance companies, by governments or by groups of nations to cede catastrophic risk to the financial markets, which are capable of supplying cover for highly destructive events, surpassing the typical capacity of traditional reinsurance contracts. Parametric cat bonds, a specific type of cat bonds, use trigger mechanisms or indices that depend on physical event parameters published by respected third parties in order to determine whether a part or the entire bond principal is to be paid for a certain event. First generation cat bonds, or cat-in-a-box bonds, display a trigger mechanism that consists of a set of geographic zones in which certain conditions need to be met by an earthquake’s magnitude and depth in order to trigger payment of the bond principal. Second generation cat bonds use an index formulation that typically consists of a sum of products of a set of weights by a polynomial function of the ground motion variables reported by a geographically distributed seismic network. These instruments are especially appealing to developing countries with incipient insurance industries wishing to cede catastrophic losses to the financial markets because the payment trigger mechanism is transparent and does not involve the parties ceding or accepting the risk, significantly reducing moral hazard. In order to be successful in the market, however, parametric cat bonds have typically been required to specify relatively simple trigger conditions. The consequence of such simplifications is the increase of basis risk. This risk represents the possibility that the trigger mechanism fails to accurately capture the actual losses of a catastrophic event, namely that it does not trigger for a highly destructive event or vice versa, that a payment of the bond principal is caused by an event that produced insignificant losses. The first case disfavors the sponsor who was seeking cover for its losses while the

  11. Competing risks regression for stratified data.

    PubMed

    Zhou, Bingqing; Latouche, Aurelien; Rocha, Vanderson; Fine, Jason

    2011-06-01

    For competing risks data, the Fine-Gray proportional hazards model for subdistribution has gained popularity for its convenience in directly assessing the effect of covariates on the cumulative incidence function. However, in many important applications, proportional hazards may not be satisfied, including multicenter clinical trials, where the baseline subdistribution hazards may not be common due to varying patient populations. In this article, we consider a stratified competing risks regression, to allow the baseline hazard to vary across levels of the stratification covariate. According to the relative size of the number of strata and strata sizes, two stratification regimes are considered. Using partial likelihood and weighting techniques, we obtain consistent estimators of regression parameters. The corresponding asymptotic properties and resulting inferences are provided for the two regimes separately. Data from a breast cancer clinical trial and from a bone marrow transplantation registry illustrate the potential utility of the stratified Fine-Gray model.

  12. Incorporating Classification Uncertainty in Competing- risks Nest- failure Analysis

    EPA Science Inventory

    Nesting birds risk nest failure due to many causes. Though partitioning risk of failure among causes has long been of interest to ornithologists, formal methods for estimating competing risk have been lacking.

  13. Competing risks regression for clustered data.

    PubMed

    Zhou, Bingqing; Fine, Jason; Latouche, Aurelien; Labopin, Myriam

    2012-07-01

    A population average regression model is proposed to assess the marginal effects of covariates on the cumulative incidence function when there is dependence across individuals within a cluster in the competing risks setting. This method extends the Fine-Gray proportional hazards model for the subdistribution to situations, where individuals within a cluster may be correlated due to unobserved shared factors. Estimators of the regression parameters in the marginal model are developed under an independence working assumption where the correlation across individuals within a cluster is completely unspecified. The estimators are consistent and asymptotically normal, and variance estimation may be achieved without specifying the form of the dependence across individuals. A simulation study evidences that the inferential procedures perform well with realistic sample sizes. The practical utility of the methods is illustrated with data from the European Bone Marrow Transplant Registry.

  14. Student Choices: Using a Competing Risks Model of Survival Analysis.

    ERIC Educational Resources Information Center

    Denson, Katy; Schumacker, Randall E.

    By using a competing risks model, survival analysis methods can be extended to predict which of several mutually exclusive outcomes students will choose based on predictor variables, thereby ascertaining if the profile of risk differs across groups. The paper begins with a brief introduction to logistic regression and some of the basic concepts of…

  15. Intervening on risk factors for coronary heart disease: an application of the parametric g-formula.

    PubMed

    Taubman, Sarah L; Robins, James M; Mittleman, Murray A; Hernán, Miguel A

    2009-12-01

    Estimating the population risk of disease under hypothetical interventions--such as the population risk of coronary heart disease (CHD) were everyone to quit smoking and start exercising or to start exercising if diagnosed with diabetes--may not be possible using standard analytic techniques. The parametric g-formula, which appropriately adjusts for time-varying confounders affected by prior exposures, is especially well suited to estimating effects when the intervention involves multiple factors (joint interventions) or when the intervention involves decisions that depend on the value of evolving time-dependent factors (dynamic interventions). We describe the parametric g-formula, and use it to estimate the effect of various hypothetical lifestyle interventions on the risk of CHD using data from the Nurses' Health Study. Over the period 1982-2002, the 20-year risk of CHD in this cohort was 3.50%. Under a joint intervention of no smoking, increased exercise, improved diet, moderate alcohol consumption and reduced body mass index, the estimated risk was 1.89% (95% confidence interval: 1.46-2.41). We discuss whether the assumptions required for the validity of the parametric g-formula hold in the Nurses' Health Study data. This work represents the first large-scale application of the parametric g-formula in an epidemiologic cohort study.

  16. Ohio Financial Services and Risk Management. Technical Competency Profile (TCP).

    ERIC Educational Resources Information Center

    Ray, Gayl M.; Wilson, Nick; Mangini, Rick

    This document describes the essential competencies from secondary through post-secondary associate degree programs for a career in financial services and risk management. Ohio College Tech Prep Program standards are described, and a key to profile codes is provided. Sample occupations in this career area, such as financial accountant, loan…

  17. Decision-making competence predicts domain-specific risk attitudes

    PubMed Central

    Weller, Joshua A.; Ceschi, Andrea; Randolph, Caleb

    2015-01-01

    Decision-making competence (DMC) reflects individual differences in rational responding across several classic behavioral decision-making tasks. Although it has been associated with real-world risk behavior, less is known about the degree to which DMC contributes to specific components of risk attitudes. Utilizing a psychological risk-return framework, we examined the associations between risk attitudes and DMC. Italian community residents (n = 804) completed an online DMC measure, using a subset of the original Adult-DMC battery. Participants also completed a self-reported risk attitude measure for three components of risk attitudes (risk-taking, risk perceptions, and expected benefits) across six risk domains. Overall, greater performance on the DMC component scales were inversely, albeit modestly, associated with risk-taking tendencies. Structural equation modeling results revealed that DMC was associated with lower perceived expected benefits for all domains. In contrast, its association with perceived risks was more domain-specific. These analyses also revealed stronger indirect effects for the DMC → expected benefits → risk-taking path than the DMC → perceived riskrisk-taking path, especially for behaviors that may be considered more maladaptive in nature. These results suggest that DMC performance differentially impacts specific components of risk attitudes, and may be more strongly related to the evaluation of expected value of a specific behavior. PMID:26029128

  18. Decision-making competence predicts domain-specific risk attitudes.

    PubMed

    Weller, Joshua A; Ceschi, Andrea; Randolph, Caleb

    2015-01-01

    Decision-making competence (DMC) reflects individual differences in rational responding across several classic behavioral decision-making tasks. Although it has been associated with real-world risk behavior, less is known about the degree to which DMC contributes to specific components of risk attitudes. Utilizing a psychological risk-return framework, we examined the associations between risk attitudes and DMC. Italian community residents (n = 804) completed an online DMC measure, using a subset of the original Adult-DMC battery. Participants also completed a self-reported risk attitude measure for three components of risk attitudes (risk-taking, risk perceptions, and expected benefits) across six risk domains. Overall, greater performance on the DMC component scales were inversely, albeit modestly, associated with risk-taking tendencies. Structural equation modeling results revealed that DMC was associated with lower perceived expected benefits for all domains. In contrast, its association with perceived risks was more domain-specific. These analyses also revealed stronger indirect effects for the DMC → expected benefits → risk-taking path than the DMC → perceived riskrisk-taking path, especially for behaviors that may be considered more maladaptive in nature. These results suggest that DMC performance differentially impacts specific components of risk attitudes, and may be more strongly related to the evaluation of expected value of a specific behavior.

  19. Semi-Competing Risks Data Analysis: Accounting for Death as a Competing Risk When the Outcome of Interest Is Nonterminal.

    PubMed

    Haneuse, Sebastien; Lee, Kyu Ha

    2016-05-01

    Hospital readmission is a key marker of quality of health care. Notwithstanding its widespread use, however, it remains controversial in part because statistical methods used to analyze readmission, primarily logistic regression and related models, may not appropriately account for patients who die before experiencing a readmission event within the time frame of interest. Toward resolving this, we describe and illustrate the semi-competing risks framework, which refers to the general setting where scientific interest lies with some nonterminal event (eg, readmission), the occurrence of which is subject to a terminal event (eg, death). Although several statistical analysis methods have been proposed for semi-competing risks data, we describe in detail the use of illness-death models primarily because of their relation to well-known methods for survival analysis and the availability of software. We also describe and consider in detail several existing approaches that could, in principle, be used to analyze semi-competing risks data, including composite end point and competing risks analyses. Throughout we illustrate the ideas and methods using data on N=49 763 Medicare beneficiaries hospitalized between 2011 and 2013 with a principle discharge diagnosis of heart failure.

  20. Crash risk analysis for Shanghai urban expressways: A Bayesian semi-parametric modeling approach.

    PubMed

    Yu, Rongjie; Wang, Xuesong; Yang, Kui; Abdel-Aty, Mohamed

    2016-10-01

    Urban expressway systems have been developed rapidly in recent years in China; it has become one key part of the city roadway networks as carrying large traffic volume and providing high traveling speed. Along with the increase of traffic volume, traffic safety has become a major issue for Chinese urban expressways due to the frequent crash occurrence and the non-recurrent congestions caused by them. For the purpose of unveiling crash occurrence mechanisms and further developing Active Traffic Management (ATM) control strategies to improve traffic safety, this study developed disaggregate crash risk analysis models with loop detector traffic data and historical crash data. Bayesian random effects logistic regression models were utilized as it can account for the unobserved heterogeneity among crashes. However, previous crash risk analysis studies formulated random effects distributions in a parametric approach, which assigned them to follow normal distributions. Due to the limited information known about random effects distributions, subjective parametric setting may be incorrect. In order to construct more flexible and robust random effects to capture the unobserved heterogeneity, Bayesian semi-parametric inference technique was introduced to crash risk analysis in this study. Models with both inference techniques were developed for total crashes; semi-parametric models were proved to provide substantial better model goodness-of-fit, while the two models shared consistent coefficient estimations. Later on, Bayesian semi-parametric random effects logistic regression models were developed for weekday peak hour crashes, weekday non-peak hour crashes, and weekend non-peak hour crashes to investigate different crash occurrence scenarios. Significant factors that affect crash risk have been revealed and crash mechanisms have been concluded.

  1. Crash risk analysis for Shanghai urban expressways: A Bayesian semi-parametric modeling approach.

    PubMed

    Yu, Rongjie; Wang, Xuesong; Yang, Kui; Abdel-Aty, Mohamed

    2016-10-01

    Urban expressway systems have been developed rapidly in recent years in China; it has become one key part of the city roadway networks as carrying large traffic volume and providing high traveling speed. Along with the increase of traffic volume, traffic safety has become a major issue for Chinese urban expressways due to the frequent crash occurrence and the non-recurrent congestions caused by them. For the purpose of unveiling crash occurrence mechanisms and further developing Active Traffic Management (ATM) control strategies to improve traffic safety, this study developed disaggregate crash risk analysis models with loop detector traffic data and historical crash data. Bayesian random effects logistic regression models were utilized as it can account for the unobserved heterogeneity among crashes. However, previous crash risk analysis studies formulated random effects distributions in a parametric approach, which assigned them to follow normal distributions. Due to the limited information known about random effects distributions, subjective parametric setting may be incorrect. In order to construct more flexible and robust random effects to capture the unobserved heterogeneity, Bayesian semi-parametric inference technique was introduced to crash risk analysis in this study. Models with both inference techniques were developed for total crashes; semi-parametric models were proved to provide substantial better model goodness-of-fit, while the two models shared consistent coefficient estimations. Later on, Bayesian semi-parametric random effects logistic regression models were developed for weekday peak hour crashes, weekday non-peak hour crashes, and weekend non-peak hour crashes to investigate different crash occurrence scenarios. Significant factors that affect crash risk have been revealed and crash mechanisms have been concluded. PMID:26847949

  2. Societal perspectives on risk awareness and risk competence

    PubMed Central

    Koller, Michael; Hoffrage, Ulrich

    2015-01-01

    Medical risks can be assessed by objectifiable therapeutic features; however, these risks are also characterised to a considerable degree by individual and social values. People tend to strive towards both freedom as well as safety; in a medical context, these two aims are taken into account by shared decision-making models and by stricter regulations in the pharmaceutical sector. Media reports on medical risks are caught between providing information and economic interests, and this conflict particularly complicates rational discussions about unexpected risks (for instance, in the field of natural medicine). Thus, it is necessary to create the type of information culture which allows differentiating between real and less pronounced risks. PMID:26195921

  3. Smoking, death, and Alzheimer disease: a case of competing risks.

    PubMed

    Chang, Chung-Chou H; Zhao, Yongyun; Lee, Ching-Wen; Ganguli, Mary

    2012-01-01

    If smoking is a risk factor for Alzheimer disease (AD) but a smoker dies of another cause before developing or manifesting AD, smoking-related mortality may mask the relationship between smoking and AD. This phenomenon, referred to as competing risk, complicates efforts to model the effect of smoking on AD. Typical survival regression models assume that censorship from analysis is unrelated to an individual's probability for developing AD (ie, censoring is noninformative). However, if individuals who die before developing AD are younger than those who survive long enough to develop AD, and if they include a higher percentage of smokers than nonsmokers, the incidence of AD will appear to be higher in older individuals and in nonsmokers. Further, age-specific mortality rates are higher in smokers because they die earlier than nonsmokers. Therefore, if we fail to take into account the competing risk of death when we estimate the effect of smoking on AD, we bias the results and are in fact only comparing the incidence of AD in nonsmokers with that in the healthiest smokers. In this study, we demonstrate that the effect of smoking on AD differs in models that are and are not adjusted for competing risks.

  4. Smoking, death, and Alzheimer disease: a case of competing risks.

    PubMed

    Chang, Chung-Chou H; Zhao, Yongyun; Lee, Ching-Wen; Ganguli, Mary

    2012-01-01

    If smoking is a risk factor for Alzheimer disease (AD) but a smoker dies of another cause before developing or manifesting AD, smoking-related mortality may mask the relationship between smoking and AD. This phenomenon, referred to as competing risk, complicates efforts to model the effect of smoking on AD. Typical survival regression models assume that censorship from analysis is unrelated to an individual's probability for developing AD (ie, censoring is noninformative). However, if individuals who die before developing AD are younger than those who survive long enough to develop AD, and if they include a higher percentage of smokers than nonsmokers, the incidence of AD will appear to be higher in older individuals and in nonsmokers. Further, age-specific mortality rates are higher in smokers because they die earlier than nonsmokers. Therefore, if we fail to take into account the competing risk of death when we estimate the effect of smoking on AD, we bias the results and are in fact only comparing the incidence of AD in nonsmokers with that in the healthiest smokers. In this study, we demonstrate that the effect of smoking on AD differs in models that are and are not adjusted for competing risks. PMID:22185783

  5. Optimising import risk mitigation: anticipating the unintended consequences and competing risks of informal trade.

    PubMed

    Hueston, W; Travis, D; van Klink, E

    2011-04-01

    The effectiveness of risk mitigation may be compromised by informal trade, including illegal activities, parallel markets and extra-legal activities. While no regulatory system is 100% effective in eliminating the risk of disease transmission through animal and animal product trade, extreme risk aversion in formal import health regulations may increase informal trade, with the unintended consequence of creating additional risks outside regulatory purview. Optimal risk mitigation on a national scale requires scientifically sound yet flexible mitigation strategies that can address the competing risks of formal and informal trade. More robust risk analysis and creative engagement of nontraditional partners provide avenues for addressing informal trade.

  6. Nonparametric Analysis of Bivariate Gap Time with Competing Risks

    PubMed Central

    Huang, Chiung-Yu; Wang, Chenguang; Wang, Mei-Cheng

    2016-01-01

    Summary This article considers nonparametric methods for studying recurrent disease and death with competing risks. We first point out that comparisons based on the well-known cumulative incidence function can be confounded by different prevalence rates of the competing events, and that comparisons of the conditional distribution of the survival time given the failure event type are more relevant for investigating the prognosis of different patterns of recurrence disease. We then propose nonparametric estimators for the conditional cumulative incidence function as well as the conditional bivariate cumulative incidence function for the bivariate gap times, that is, the time to disease recurrence and the residual lifetime after recurrence. To quantify the association between the two gap times in the competing risks setting, a modified Kendall’s tau statistic is proposed. The proposed estimators for the conditional bivariate cumulative incidence distribution and the association measure account for the induced dependent censoring for the second gap time. Uniform consistency and weak convergence of the proposed estimators are established. Hypothesis testing procedures for two-sample comparisons are discussed. Numerical simulation studies with practical sample sizes are conducted to evaluate the performance of the proposed nonparametric estimators and tests. An application to data from a pancreatic cancer study is presented to illustrate the methods developed in this article. PMID:26990686

  7. Risk Taking: A Required Competency for Merger, Acquisitions, and Partnerships.

    PubMed

    Trepanier, Sylvain; Crenshaw, Jeannette T; Yoder-Wise, Patricia S

    2016-01-01

    Today's nurse executive is likely to find himself or herself in the middle of a merger, acquisition, and/or partnership (MAP). This is the result of health care agencies vying for market share in the midst of stiff competition, as well as decreased reimbursement in a rapidly changing payment system. The phenomenon of MAPs is fueled by the focus on care coordination and population health management. To be prepared for the ongoing and increasing MAP activity, nurse executives need to develop the skill of risk taking as an essential competency for leading change. This article emphasizes the need to maintain and improve health care quality and patient safety.

  8. Risk Taking: A Required Competency for Merger, Acquisitions, and Partnerships.

    PubMed

    Trepanier, Sylvain; Crenshaw, Jeannette T; Yoder-Wise, Patricia S

    2016-01-01

    Today's nurse executive is likely to find himself or herself in the middle of a merger, acquisition, and/or partnership (MAP). This is the result of health care agencies vying for market share in the midst of stiff competition, as well as decreased reimbursement in a rapidly changing payment system. The phenomenon of MAPs is fueled by the focus on care coordination and population health management. To be prepared for the ongoing and increasing MAP activity, nurse executives need to develop the skill of risk taking as an essential competency for leading change. This article emphasizes the need to maintain and improve health care quality and patient safety. PMID:27584889

  9. The application of cure models in the presence of competing risks: a tool for improved risk communication in population-based cancer patient survival.

    PubMed

    Eloranta, Sandra; Lambert, Paul C; Andersson, Therese M-L; Björkholm, Magnus; Dickman, Paul W

    2014-09-01

    Quantifying cancer patient survival from the perspective of cure is clinically relevant. However, most cure models estimate cure assuming no competing causes of death. We use a relative survival framework to demonstrate how flexible parametric cure models can be used in combination with competing-risks theory to incorporate noncancer deaths. Under a model that incorporates statistical cure, we present the probabilities that cancer patients (1) have died from their cancer, (2) have died from other causes, (3) will eventually die from their cancer, or (4) will eventually die from other causes, all as a function of time since diagnosis. We further demonstrate how conditional probabilities can be used to update the prognosis among survivors (eg, at 1 or 5 years after diagnosis) by summarizing the proportion of patients who will not die from their cancer. The proposed method is applied to Swedish population-based data for persons diagnosed with melanoma, colon cancer, or acute myeloid leukemia between 1973 and 2007.

  10. A new flexible dependence measure for semi-competing risks.

    PubMed

    Yang, Jing; Peng, Limin

    2016-09-01

    Semi-competing risks data are often encountered in chronic disease follow-up studies that record both nonterminal events (e.g., disease landmark events) and terminal events (e.g., death). Studying the relationship between the nonterminal event and the terminal event can provide insightful information on disease progression. In this article, we propose a new sensible dependence measure tailored to addressing such an interest. We develop a nonparametric estimator, which is general enough to handle both independent right censoring and left truncation. Our strategy of connecting the new dependence measure with quantile regression enables a natural extension to adjust for covariates with minor additional assumptions imposed. We establish the asymptotic properties of the proposed estimators and develop inferences accordingly. Simulation studies suggest good finite-sample performance of the proposed methods. Our proposals are illustrated via an application to Denmark diabetes registry data. PMID:26916804

  11. Developing points-based risk-scoring systems in the presence of competing risks.

    PubMed

    Austin, Peter C; Lee, Douglas S; D'Agostino, Ralph B; Fine, Jason P

    2016-09-30

    Predicting the occurrence of an adverse event over time is an important issue in clinical medicine. Clinical prediction models and associated points-based risk-scoring systems are popular statistical methods for summarizing the relationship between a multivariable set of patient risk factors and the risk of the occurrence of an adverse event. Points-based risk-scoring systems are popular amongst physicians as they permit a rapid assessment of patient risk without the use of computers or other electronic devices. The use of such points-based risk-scoring systems facilitates evidence-based clinical decision making. There is a growing interest in cause-specific mortality and in non-fatal outcomes. However, when considering these types of outcomes, one must account for competing risks whose occurrence precludes the occurrence of the event of interest. We describe how points-based risk-scoring systems can be developed in the presence of competing events. We illustrate the application of these methods by developing risk-scoring systems for predicting cardiovascular mortality in patients hospitalized with acute myocardial infarction. Code in the R statistical programming language is provided for the implementation of the described methods. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. PMID:27197622

  12. Quantifying Cancer Absolute Risk and Cancer Mortality in the Presence of Competing Events after a Myotonic Dystrophy Diagnosis

    PubMed Central

    Gadalla, Shahinaz M.; Pfeiffer, Ruth M.; Kristinsson, Sigurdur Y.; Björkholm, Magnus; Hilbert, James E.; Moxley, Richard T.; Landgren, Ola; Greene, Mark H.

    2013-01-01

    Recent studies show that patients with myotonic dystrophy (DM) have an increased risk of specific malignancies, but estimates of absolute cancer risk accounting for competing events are lacking. Using the Swedish Patient Registry, we identified 1,081 patients with an inpatient and/or outpatient diagnosis of DM between 1987 and 2007. Date and cause of death and date of cancer diagnosis were extracted from the Swedish Cause of Death and Cancer Registries. We calculated non-parametric estimates of absolute cancer risk and cancer mortality accounting for the high non-cancer competing mortality associated with DM. Absolute cancer risk after DM diagnosis was 1.6% (95% CI=0.4-4%), 5% (95% CI=3-9%) and 9% (95% CI=6-13%) at ages 40, 50 and 60 years, respectively. Females had a higher absolute risk of all cancers combined than males: 9% (95% CI=4-14), and 13% (95% CI=9-20) vs. 2% (95%CI= 0.7-6) and 4% (95%CI=2-8) by ages 50 and 60 years, respectively) and developed cancer at younger ages (median age =51 years, range=22-74 vs. 57, range=43-84, respectively, p=0.02). Cancer deaths accounted for 10% of all deaths, with an absolute cancer mortality risk of 2% (95%CI=1-4.5%), 4% (95%CI=2-6%), and 6% (95%CI=4-9%) by ages 50, 60, and 70 years, respectively. No gender difference in cancer-specific mortality was observed (p=0.6). In conclusion, cancer significantly contributes to morbidity and mortality in DM patients, even after accounting for high competing DM mortality from non-neoplastic causes. It is important to apply population-appropriate, validated cancer screening strategies in DM patients. PMID:24236163

  13. A Method for Evaluating Competency in Assessment and Management of Suicide Risk

    ERIC Educational Resources Information Center

    Hung, Erick K.; Binder, Renee L.; Fordwood, Samantha R.; Hall, Stephen E.; Cramer, Robert J.; McNiel, Dale E.

    2012-01-01

    Objective: Although health professionals increasingly are expected to be able to assess and manage patients' risk for suicide, few methods are available to evaluate this competency. This report describes development of a competency-assessment instrument for suicide risk-assessment (CAI-S), and evaluates its use in an objective structured clinical…

  14. Evaluating eye injury risk of Airsoft pellet guns by parametric risk functions.

    PubMed

    Kennedy, Eric A; Ng, Tracy P; Duma, Stefan M

    2006-01-01

    Over 2.4 million eye injuries occur each year in the United States as a result of trauma. New toy guns, commonly referred to as Airsoft guns are increasingly becoming responsible for ocular injuries in children. The purpose of this study was to determine the ocular injury risk of these Airsoft guns by experimental testing and the use of previously generated ocular injury risk functions. A total of 26 Airsoft pellet impact tests were performed on both post-mortem human and porcine eyes in a laboratory environment. Projectile parameters of diameter, mass, and velocity were used to calculate the injury potential of these impacts for five different ocular injuries: corneal abrasion, lens dislocation, hyphema, retinal damage, and globe rupture. Globe rupture was not observed in any of the experimental tests, which is consistent with that reported in the literature. The two most likely ocular injuries caused by these Airsoft guns are corneal abrasion and hyphema, at nearly a 100% and a greater than 75% risk of injury, respectively. This is consistent with the types of injuries reported in the literature, with corneal abrasion and hyphema being the most frequently occurring ocular injuries due to Airsoft guns. More experimental data on retinal injuries is necessary to make an accurate assessment of the risk of retinal damage from blunt impacts. In summary, the potential for ocular injury from Airsoft guns is great and protective equipment such as protective eyewear should be considered mandatory during operation.

  15. Competing risks analyses for recurrence from primary breast cancer

    PubMed Central

    Chapman, J W; Fish, E B; Link, M A

    1999-01-01

    The effects of prognostic factors on local, regional or distant metastasis are standardly assessed separately. Competing risks analyses may be used to assess simultaneously the effects of factors on different types of first recurrence. Data for a cohort of 678 primary invasive breast cancer patients accrued between 1971 and 1990, updated to 1995, included type of first recurrence (local, regional, distant). We investigated the effects of the traditional factors of age, tumour size, nodal status, ER, PgR, adjuvant therapy (hormones, chemotherapy, radiotherapy) on type of recurrence and time to recurrence for all patients and for those aged ≥ 65. For all ages of patients, there were five factors with significant associations with type or time to first recurrence. Adjuvant radiation was the only factor which had an effect (P ≤ 0.05) on the type of first recurrence: being associated with a reduction in local recurrence. Age, nodal status, tumour size and adjuvant chemotherapy all had significant associations across all types of first recurrence, and in particular with time to recurrence for both local and distant metastasis. This indicates a potential lack of independence in these end-points. For patients ≥ 65 years of age, there were no factors which differentially affected type of recurrence, while only nodal status and tumour size had significant associations with time to recurrence. Analyses were used to assess simultaneously the effects of traditional prognostic factors and treatment options on type of first recurrence and time to first recurrence. The extension to evaluations with newer prognostic factors would expedite the determination and mode of biologic activity for such factors. © 1999 Cancer Research Campaign PMID:10188898

  16. Media influence on risk competence in self-medication and self-treatment.

    PubMed

    Schweim, Harald; Ullmann, Marcela

    2015-01-01

    Media play an important role in the reception of health risks; thus, media competence is important for enhancing the risk competence of patients and consumers. In addition to life-long health education, risk competence particularly requires careful handling of health information because, at present, the key problem is not the lack of sufficient information on health topics but the quality of such information. Patients and consumers of health procedures and health products also require information which relates to their daily life and matches their life style. PMID:26195923

  17. Media influence on risk competence in self-medication and self-treatment

    PubMed Central

    Schweim, Harald; Ullmann, Marcela

    2015-01-01

    Media play an important role in the reception of health risks; thus, media competence is important for enhancing the risk competence of patients and consumers. In addition to life-long health education, risk competence particularly requires careful handling of health information because, at present, the key problem is not the lack of sufficient information on health topics but the quality of such information. Patients and consumers of health procedures and health products also require information which relates to their daily life and matches their life style. PMID:26195923

  18. Media influence on risk competence in self-medication and self-treatment.

    PubMed

    Schweim, Harald; Ullmann, Marcela

    2015-01-01

    Media play an important role in the reception of health risks; thus, media competence is important for enhancing the risk competence of patients and consumers. In addition to life-long health education, risk competence particularly requires careful handling of health information because, at present, the key problem is not the lack of sufficient information on health topics but the quality of such information. Patients and consumers of health procedures and health products also require information which relates to their daily life and matches their life style.

  19. Predicting Emotional and Social Competence during Early Childhood from Toddler Risk and Maternal Behavior

    PubMed Central

    Blandon, Alysia Y.; Calkins, Susan D.; Keane, Susan P.

    2010-01-01

    The longitudinal associations between maternal parenting behavior and toddler risk with children’s emotional and social competence were examined during the transition to kindergarten, in a sample of 253 children. Toddler risk was characterized by early externalizing behavior and poor emotion regulation skills. Given that we were interested in the multiple pathways that may result in emotional and social competence, we examined the interactions among maternal parenting behavior and toddler risk. There were some significant interactions; although the pattern of results was not consistent across all competence outcomes. Maternal parenting behavior was not directly associated with children’s emotional and social competence. In some instances, maternal control has differential implications for children’s emotional and social competence dependent upon the child’s level of early risk and maternal positive parenting. Specifically, maternal control tended to be more detrimental for children’s emotional competence during the transition to kindergarten, when children exhibit higher levels of risk. Overall, it appears that there are multiple developmental pathways, depending on child and maternal characteristics that lead to early emotional and social competence. PMID:20102651

  20. [Non-Parametric Analysis of Radiation Risks of Mortality among Chernobyl Clean-Up Workers].

    PubMed

    Gorsky, A I; Maksioutov, M A; Tumanov, K A; Shchukina, N V; Chekin, S Yu; Ivanov, V K

    2016-01-01

    Analysis of the relationship between dose and mortality from cancer and circulation diseases in the cohort of Chernobyl clean-up workers based on the data from the National Radiation and Epidemiological Registry was performed. Medical and dosimetry information on the clean-up workers, males, who got radiation doses from April 26, 1986 to April 26, 1987, which was accumulated from 1992 to 2012, was used for the analysis. The total size of the cohort was 42929 people, 12731 deaths were registered in the cohort, among them 1893 deaths from solid cancers and 5230 deaths were from circulation diseases. An average age of the workers was 39 years in 1992 and the mean dose was 164 mGy. The dose-effect relationship was estimated with the use of non-parametric analysis of survival with regard to concurrence of risks of mortality. The risks were estimated in 6 dose groups of similar size (1-70, 70-130, 130-190, 190-210, 210-230 and.230-1000 mGy). The group "1-70 mGy" was used as control. Estimated dose-effect relationship related to cancers and circulation diseases is described approximately with a linear model, coefficient of determination (the proportion of variability explained by the linear model) for cancers was 23-25% and for circulation diseases - 2-13%. The slope coefficient of the dose-effect relationship normalized to 1 Gy for the ratio of risks for cancers in the linear model was 0.47 (95% CI: -0.77, 1.71), and for circulation diseases it was 0.22 (95% CI: -0.58, 1.02). Risks coefficient (slope coefficient of excess mortality at a dose of 1 Gy) for solid cancers was 1.94 (95% CI: - 3.10, 7.00) x 10(-2) and for circulation diseases it was 0.67 (95% CI: -9.61, 11.00) x 10(-2). 137 deaths from radiation-induced cancers and 47 deaths from circulation diseases were registered during a follow up period. PMID:27534064

  1. [Non-Parametric Analysis of Radiation Risks of Mortality among Chernobyl Clean-Up Workers].

    PubMed

    Gorsky, A I; Maksioutov, M A; Tumanov, K A; Shchukina, N V; Chekin, S Yu; Ivanov, V K

    2016-01-01

    Analysis of the relationship between dose and mortality from cancer and circulation diseases in the cohort of Chernobyl clean-up workers based on the data from the National Radiation and Epidemiological Registry was performed. Medical and dosimetry information on the clean-up workers, males, who got radiation doses from April 26, 1986 to April 26, 1987, which was accumulated from 1992 to 2012, was used for the analysis. The total size of the cohort was 42929 people, 12731 deaths were registered in the cohort, among them 1893 deaths from solid cancers and 5230 deaths were from circulation diseases. An average age of the workers was 39 years in 1992 and the mean dose was 164 mGy. The dose-effect relationship was estimated with the use of non-parametric analysis of survival with regard to concurrence of risks of mortality. The risks were estimated in 6 dose groups of similar size (1-70, 70-130, 130-190, 190-210, 210-230 and.230-1000 mGy). The group "1-70 mGy" was used as control. Estimated dose-effect relationship related to cancers and circulation diseases is described approximately with a linear model, coefficient of determination (the proportion of variability explained by the linear model) for cancers was 23-25% and for circulation diseases - 2-13%. The slope coefficient of the dose-effect relationship normalized to 1 Gy for the ratio of risks for cancers in the linear model was 0.47 (95% CI: -0.77, 1.71), and for circulation diseases it was 0.22 (95% CI: -0.58, 1.02). Risks coefficient (slope coefficient of excess mortality at a dose of 1 Gy) for solid cancers was 1.94 (95% CI: - 3.10, 7.00) x 10(-2) and for circulation diseases it was 0.67 (95% CI: -9.61, 11.00) x 10(-2). 137 deaths from radiation-induced cancers and 47 deaths from circulation diseases were registered during a follow up period.

  2. Suicide Risk Assessment Training for Psychology Doctoral Programs: Core Competencies and a Framework for Training

    PubMed Central

    Cramer, Robert J.; Johnson, Shara M.; McLaughlin, Jennifer; Rausch, Emilie M.; Conroy, Mary Alice

    2014-01-01

    Clinical and counseling psychology programs currently lack adequate evidence-based competency goals and training in suicide risk assessment. To begin to address this problem, this article proposes core competencies and an integrated training framework that can form the basis for training and research in this area. First, we evaluate the extent to which current training is effective in preparing trainees for suicide risk assessment. Within this discussion, sample and methodological issues are reviewed. Second, as an extension of these methodological training issues, we integrate empirically- and expert-derived suicide risk assessment competencies from several sources with the goal of streamlining core competencies for training purposes. Finally, a framework for suicide risk assessment training is outlined. The approach employs Objective Structured Clinical Examination (OSCE) methodology, an approach commonly utilized in medical competency training. The training modality also proposes the Suicide Competency Assessment Form (SCAF), a training tool evaluating self- and observer-ratings of trainee core competencies. The training framework and SCAF are ripe for empirical evaluation and potential training implementation. PMID:24672588

  3. Suicide Risk Assessment Training for Psychology Doctoral Programs: Core Competencies and a Framework for Training.

    PubMed

    Cramer, Robert J; Johnson, Shara M; McLaughlin, Jennifer; Rausch, Emilie M; Conroy, Mary Alice

    2013-02-01

    Clinical and counseling psychology programs currently lack adequate evidence-based competency goals and training in suicide risk assessment. To begin to address this problem, this article proposes core competencies and an integrated training framework that can form the basis for training and research in this area. First, we evaluate the extent to which current training is effective in preparing trainees for suicide risk assessment. Within this discussion, sample and methodological issues are reviewed. Second, as an extension of these methodological training issues, we integrate empirically- and expert-derived suicide risk assessment competencies from several sources with the goal of streamlining core competencies for training purposes. Finally, a framework for suicide risk assessment training is outlined. The approach employs Objective Structured Clinical Examination (OSCE) methodology, an approach commonly utilized in medical competency training. The training modality also proposes the Suicide Competency Assessment Form (SCAF), a training tool evaluating self- and observer-ratings of trainee core competencies. The training framework and SCAF are ripe for empirical evaluation and potential training implementation.

  4. Use of competing conceptions of risk in animal agriculture.

    PubMed

    Kunkel, H O; Thompson, P B; Miller, B A; Skaggs, C L

    1998-03-01

    This study considers a theory of risk as a means of coping with risk and uncertainty that have become a growing reality for animal agriculture. Microbial contaminations of food, waste management, animal products in the human diet, and transmissible spongiform encephalopathies (TSE) incorporate different conceptions of risk and require different approaches to handling the uncertainty involved. A dichotomous schema is suggested to assist understanding risk that may be adapted to recognizing and handling risk. The polar aspects of the proposal are the probabilistic approach at one end and the contextual understanding at the other. Probabilist conceptions of risk presume that risk is determined by probability and consequence. Contextual conceptions presume that management, law, regulation, media, and public perceptions, as well as the severity of the consequence, will figure prominently in decision making in the face of uncertainty. Relative emphasis on probabilistic characteristics shapes distinct understandings of risk that can be plotted between the poles. We are proposing that these conceptualizations need not be issues only for debate but also for recognition of the probabilistic or contextual nature of the risk. Specific actions and policy may be constructed on the basis of the conceptualization. The bovine spongiform encephalopathy/new variant Creutzfeldt-Jakob disease complex is examined philosophically and methodologically as a contextual challenge to animal agriculture and associated industries. As such, the TSE serve as a case study of effective application of risk theory to risks in animal agriculture. PMID:9535327

  5. Core Competencies and the Prevention of High-Risk Sexual Behavior

    ERIC Educational Resources Information Center

    Charles, Vignetta Eugenia; Blum, Robert Wm.

    2008-01-01

    Adolescent sexual risk-taking behavior has numerous individual, family, community, and societal consequences. In an effort to contribute to the research and propose new directions, this chapter applies the core competencies framework to the prevention of high-risk sexual behavior. It describes the magnitude of the problem, summarizes explanatory…

  6. Introduction to the Analysis of Survival Data in the Presence of Competing Risks.

    PubMed

    Austin, Peter C; Lee, Douglas S; Fine, Jason P

    2016-02-01

    Competing risks occur frequently in the analysis of survival data. A competing risk is an event whose occurrence precludes the occurrence of the primary event of interest. In a study examining time to death attributable to cardiovascular causes, death attributable to noncardiovascular causes is a competing risk. When estimating the crude incidence of outcomes, analysts should use the cumulative incidence function, rather than the complement of the Kaplan-Meier survival function. The use of the Kaplan-Meier survival function results in estimates of incidence that are biased upward, regardless of whether the competing events are independent of one another. When fitting regression models in the presence of competing risks, researchers can choose from 2 different families of models: modeling the effect of covariates on the cause-specific hazard of the outcome or modeling the effect of covariates on the cumulative incidence function. The former allows one to estimate the effect of the covariates on the rate of occurrence of the outcome in those subjects who are currently event free. The latter allows one to estimate the effect of covariates on the absolute risk of the outcome over time. The former family of models may be better suited for addressing etiologic questions, whereas the latter model may be better suited for estimating a patient's clinical prognosis. We illustrate the application of these methods by examining cause-specific mortality in patients hospitalized with heart failure. Statistical software code in both R and SAS is provided. PMID:26858290

  7. Students "At-Risk" Policy: Competing Social and Economic Discourses

    ERIC Educational Resources Information Center

    Mosen-Lowe, Linda Audrey Joy; Vidovich, Lesley; Chapman, Anne

    2009-01-01

    Within a context of global reform agendas that promote economic ideologies in education the discourses surrounding "school failure" have shifted from "individual risk" to "a nation at-risk". Enhancing the quality of schooling through improving educational outcomes and standards for all, and thereby reducing "school failure," is simultaneously…

  8. Self-criticism of physicians, patient participation and risk competence

    PubMed Central

    Wolffsohn, Michael

    2015-01-01

    Self-criticism of physicians and patient participation are the pillars of modern medical ethics and medical programmes. Patients expect risk minimisation from physicians, mostly without realising how much they could actively do themselves in this respect. But what about the willingness of German people to take risks, how high is it really at present? Direct empirical data are not available, but results from general empirical research show that people’s willingness to take risks is probably rather low. Post-heroic societies of welfare states are less likely to take risks than supposedly heroic ones. Therefore, the question whether it is responsible for medical experts to transfer even more responsibility to non-medical laypeople becomes increasingly important in a social context. PMID:26195919

  9. Do Health Professionals Need Additional Competencies for Stratified Cancer Prevention Based on Genetic Risk Profiling?

    PubMed Central

    Chowdhury, Susmita; Henneman, Lidewij; Dent, Tom; Hall, Alison; Burton, Alice; Pharoah, Paul; Pashayan, Nora; Burton, Hilary

    2015-01-01

    There is growing evidence that inclusion of genetic information about known common susceptibility variants may enable population risk-stratification and personalized prevention for common diseases including cancer. This would require the inclusion of genetic testing as an integral part of individual risk assessment of an asymptomatic individual. Front line health professionals would be expected to interact with and assist asymptomatic individuals through the risk stratification process. In that case, additional knowledge and skills may be needed. Current guidelines and frameworks for genetic competencies of non-specialist health professionals place an emphasis on rare inherited genetic diseases. For common diseases, health professionals do use risk assessment tools but such tools currently do not assess genetic susceptibility of individuals. In this article, we compare the skills and knowledge needed by non-genetic health professionals, if risk-stratified prevention is implemented, with existing competence recommendations from the UK, USA and Europe, in order to assess the gaps in current competences. We found that health professionals would benefit from understanding the contribution of common genetic variations in disease risk, the rationale for a risk-stratified prevention pathway, and the implications of using genomic information in risk-assessment and risk management of asymptomatic individuals for common disease prevention. PMID:26068647

  10. Are women as likely to take risks and compete? Behavioural findings from central Vietnam.

    PubMed

    Fletschner, Diana; Anderson, C Leigh; Cullen, Alison

    2010-01-01

    Using controlled experiments to compare the risk attitude and willingness to compete of husbands and wives in 500 couples in rural Vietnam, we find that women are more risk averse than men and that, compared to men, women are less likely to choose to compete, irrespective of how likely they are to succeed. Relevant to development programmes concerned with lifting women out of poverty, our findings suggest that women may be more reluctant to adopt new technologies, take out loans, or engage in economic activities that offer higher expected returns, in order to avoid setups that require them to be more competitive or that have less predictable outcomes. PMID:21125722

  11. Trustworthy patient decision aids: a qualitative analysis addressing the risk of competing interests

    PubMed Central

    Elwyn, Glyn; Dannenberg, Michelle; Blaine, Arianna; Poddar, Urbashi; Durand, Marie-Anne

    2016-01-01

    Objective Our aim in this study was to examine the competing interest policies and procedures of organisations who develop and maintain patient decision aids. Design Descriptive and thematic analysis of data collected from a cross-sectional survey of patient decision aid developer's competing interest policies and disclosure forms. Results We contacted 25 organisations likely to meet the inclusion criteria. 12 eligible organisations provided data. 11 organisations did not reply and 2 declined to participate. Most patient decision aid developers recognise the need to consider the issue of competing interests. Assessment processes vary widely and, for the most part, are insufficiently robust to minimise the risk of competing interests. Only half of the 12 organisations had competing interest policies. Some considered disclosure to be sufficient, while others imposed differing levels of exclusion. Conclusions Patient decision aid developers do not have a consistent approach to managing competing interests. Some have developed policies and procedures, while others pay no attention to the issue. As is the case for clinical practice guidelines, increasing attention will need to be given to how the competing interests of contributors of evidence-based publications may influence materials, especially if they are designed for patient use. PMID:27612542

  12. Evidence-based health information and risk competence

    PubMed Central

    Mühlhauser, Ingrid; Albrecht, Martina; Steckelberg, Anke

    2015-01-01

    Consumers and patients want to be included in decisions regarding their own health and have an ethically justified claim on informed decisions. Therefore, sound information is required, but health information is often misleading and based on different interests. The risks of disease and the benefits of medical interventions tend to be overestimated, whereas harm is often underestimated. Evidence-based health information has to fulfil certain criteria, for instance, it should be evidence-based, independent, complete, true as well as understandable. The aim of a medical intervention has to be explained. The different therapeutic options including the option not to intervene have to be delineated. The probabilities for success, lack of success and unwanted side effects have to be communicated in a numerical and understandable manner. Patients have the right to reject medical interventions without any sanctions. PMID:26195924

  13. Intelligence quotient discrepancy indicates levels of motor competence in preschool children at risk for developmental delays

    PubMed Central

    Yu, Tzu-Ying; Chen, Kuan-Lin; Chou, Willy; Yang, Shu-Han; Kung, Sheng-Chun; Lee, Ya-Chen; Tung, Li-Chen

    2016-01-01

    Purpose This study aimed to establish 1) whether a group difference exists in the motor competence of preschool children at risk for developmental delays with intelligence quotient discrepancy (IQD; refers to difference between verbal intelligence quotient [VIQ] and performance intelligence quotient [PIQ]) and 2) whether an association exists between IQD and motor competence. Methods Children’s motor competence and IQD were determined with the motor subtests of the Comprehensive Developmental Inventory for Infants and Toddlers and Wechsler Preschool and Primary Scale of Intelligence™ – Fourth Edition. A total of 291 children were included in three groups: NON-IQD (n=213; IQD within 1 standard deviation [SD]), VIQ>PIQ (n=39; VIQ>PIQ greater than 1 SD), and PIQ>VIQ (n=39; PIQ>VIQ greater than 1 SD). Results The results of one-way analysis of variance indicated significant differences among the subgroups for the “Gross and fine motor” subdomains of the Comprehensive Developmental Inventory for Infants and Toddlers, especially on the subtests of “body-movement coordination” (F=3.87, P<0.05) and “visual-motor coordination” (F=6.90, P<0.05). Motor competence was significantly worse in the VIQ>PIQ group than in the NON and PIQ>VIQ groups. Significant negative correlations between IQD and most of the motor subtests (r=0.31–0.46, P<0.01) were found only in the VIQ>PIQ group. Conclusion This study demonstrates that 1) IQD indicates the level of motor competence in preschoolers at risk for developmental delays and 2) IQD is negatively associated with motor competence in preschoolers with significant VIQ>PIQ discrepancy. The first finding was that preschoolers with VIQ>PIQ discrepancy greater than 1 SD performed significantly worse on motor competence than did preschoolers without significant IQD and preschoolers with PIQ>VIQ discrepancy greater than 1 SD. However, preschoolers with significant PIQ>VIQ discrepancy performed better on motor competence than

  14. A proportional hazards regression model for the subdistribution with right-censored and left-truncated competing risks data.

    PubMed

    Zhang, Xu; Zhang, Mei-Jie; Fine, Jason

    2011-07-20

    With competing risks failure time data, one often needs to assess the covariate effects on the cumulative incidence probabilities. Fine and Gray proposed a proportional hazards regression model to directly model the subdistribution of a competing risk. They developed the estimating procedure for right-censored competing risks data, based on the inverse probability of censoring weighting. Right-censored and left-truncated competing risks data sometimes occur in biomedical researches. In this paper, we study the proportional hazards regression model for the subdistribution of a competing risk with right-censored and left-truncated data. We adopt a new weighting technique to estimate the parameters in this model. We have derived the large sample properties of the proposed estimators. To illustrate the application of the new method, we analyze the failure time data for children with acute leukemia. In this example, the failure times for children who had bone marrow transplants were left truncated.

  15. A Novel Risk Score to the Prediction of 10-year Risk for Coronary Artery Disease Among the Elderly in Beijing Based on Competing Risk Model

    PubMed Central

    Liu, Long; Tang, Zhe; Li, Xia; Luo, Yanxia; Guo, Jin; Li, Haibin; Liu, Xiangtong; Tao, Lixin; Yan, Aoshuang; Guo, Xiuhua

    2016-01-01

    Abstract The study aimed to construct a risk prediction model for coronary artery disease (CAD) based on competing risk model among the elderly in Beijing and develop a user-friendly CAD risk score tool. We used competing risk model to evaluate the risk of developing a first CAD event. On the basis of the risk factors that were included in the competing risk model, we constructed the CAD risk prediction model with Cox proportional hazard model. Time-dependent receiver operating characteristic (ROC) curve and time-dependent area under the ROC curve (AUC) were used to evaluate the discrimination ability of the both methods. Calibration plots were applied to assess the calibration ability and adjusted for the competing risk of non-CAD death. Net reclassification index (NRI) and integrated discrimination improvement (IDI) were applied to quantify the improvement contributed by the new risk factors. Internal validation of predictive accuracy was performed using 1000 times of bootstrap re-sampling. Of the 1775 participants without CAD at baseline, 473 incident cases of CAD were documented for a 20-year follow-up. Time-dependent AUCs for men and women at t = 10 years were 0.841 [95% confidence interval (95% CI): 0.806–0.877], 0.804 (95% CI: 0.768–0.839) in Fine and Gray model, 0.784 (95% CI: 0.738–0.830), 0.733 (95% CI: 0.692–0.775) in Cox proportional hazard model. The competing risk model was significantly superior to Cox proportional hazard model on discrimination and calibration. The cut-off values of the risk score that marked the difference between low-risk and high-risk patients were 34 points for men and 30 points for women, which have good sensitivity and specificity. A sex-specific multivariable risk factor algorithm-based competing risk model has been developed on the basis of an elderly Chinese cohort, which could be applied to predict an individual's risk and provide a useful guide to identify the groups at a high risk for CAD among the Chinese

  16. A Novel Risk Score to the Prediction of 10-year Risk for Coronary Artery Disease Among the Elderly in Beijing Based on Competing Risk Model.

    PubMed

    Liu, Long; Tang, Zhe; Li, Xia; Luo, Yanxia; Guo, Jin; Li, Haibin; Liu, Xiangtong; Tao, Lixin; Yan, Aoshuang; Guo, Xiuhua

    2016-03-01

    The study aimed to construct a risk prediction model for coronary artery disease (CAD) based on competing risk model among the elderly in Beijing and develop a user-friendly CAD risk score tool. We used competing risk model to evaluate the risk of developing a first CAD event. On the basis of the risk factors that were included in the competing risk model, we constructed the CAD risk prediction model with Cox proportional hazard model. Time-dependent receiver operating characteristic (ROC) curve and time-dependent area under the ROC curve (AUC) were used to evaluate the discrimination ability of the both methods. Calibration plots were applied to assess the calibration ability and adjusted for the competing risk of non-CAD death. Net reclassification index (NRI) and integrated discrimination improvement (IDI) were applied to quantify the improvement contributed by the new risk factors. Internal validation of predictive accuracy was performed using 1000 times of bootstrap re-sampling. Of the 1775 participants without CAD at baseline, 473 incident cases of CAD were documented for a 20-year follow-up. Time-dependent AUCs for men and women at t = 10 years were 0.841 [95% confidence interval (95% CI): 0.806-0.877], 0.804 (95% CI: 0.768-0.839) in Fine and Gray model, 0.784 (95% CI: 0.738-0.830), 0.733 (95% CI: 0.692-0.775) in Cox proportional hazard model. The competing risk model was significantly superior to Cox proportional hazard model on discrimination and calibration. The cut-off values of the risk score that marked the difference between low-risk and high-risk patients were 34 points for men and 30 points for women, which have good sensitivity and specificity. A sex-specific multivariable risk factor algorithm-based competing risk model has been developed on the basis of an elderly Chinese cohort, which could be applied to predict an individual's risk and provide a useful guide to identify the groups at a high risk for CAD among the Chinese adults over 55

  17. Competence, risk, and resilience in military families: conceptual commentary.

    PubMed

    Masten, Ann S

    2013-09-01

    This commentary highlights conceptual themes in the opening section of this special issue on military families in relation to a new synthesis of developmental systems theory that emerged from developmental, ecological, and family systems theory, as well as developmental psychopathology and risk/resilience frameworks. Articles in this special issue draw on these concepts to characterize and guide the burgeoning research on military families. This perspective emphasizes that multiple dynamic systems interact across levels to shape individual development, as well as the function of families and military units. Developmental timing is important for understanding how challenges of military life may impact individuals and families. Cascade effects are noted, where stress experienced by one family or service member can influence the function of other individuals or larger systems. Capacity for resilience is distributed across systems, including families and cultures, as well as resources or supports provided by military organizations to foster adaptive responses or recovery. These systems include schools and educational programs that play key roles in fostering and supporting resilience for children. Overall, developmental system concepts have considerable utility for guiding research with military families, particularly in regard to promoting resilience. Moreover, lessons learned from military families and programs may have much broader implications for many other nonmilitary children, families, and organizations that share similar goals and challenges.

  18. [Assessment of risk of burden in construction: improvement interventions and contribution of the competent physician].

    PubMed

    Martinelli, R; Tarquini, M

    2012-01-01

    Three construction companies in three years have changed the operating modes, making use of innovative carpentry, with little amount of equipment, improved usability of the site, reduced cleaning time, less manual handling and reduced risk of accidents. The Competent Doctor has participated in the review of the risk assessment of manual handling: data has been acquired on musculoskeletal disorders to compare, in terms of this innovation, the average trend and changes, with encouraging results in terms of incidence of musculoskeletal disorders, absenteeism due to illness by these causes, new cases of lumbar diseases. It remains difficult in building to assess manual handling risk, but the collaboration between the Employer, Prevention and Protection Service and Competent Doctor, thanks to the greater attention that the design subject to these issues, suggests improvements and further steps to extend to all phases of operation of building.

  19. Improved Method to Stratify Elderly Patients With Cancer at Risk for Competing Events

    PubMed Central

    Carmona, Ruben; Zakeri, Kaveh; Green, Garrett; Hwang, Lindsay; Gulaya, Sachin; Xu, Beibei; Verma, Rohan; Williamson, Casey W.; Triplett, Daniel P.; Rose, Brent S.; Shen, Hanjie; Vaida, Florin; Murphy, James D.

    2016-01-01

    Purpose To compare a novel generalized competing event (GCE) model versus the standard Cox proportional hazards regression model for stratifying elderly patients with cancer who are at risk for competing events. Methods We identified 84,319 patients with nonmetastatic prostate, head and neck, and breast cancers from the SEER-Medicare database. Using demographic, tumor, and clinical characteristics, we trained risk scores on the basis of GCE versus Cox models for cancer-specific mortality and all-cause mortality. In test sets, we examined the predictive ability of the risk scores on the different causes of death, including second cancer mortality, noncancer mortality, and cause-specific mortality, using Fine-Gray regression and area under the curve. We compared how well models stratified subpopulations according to the ratio of the cumulative cause-specific hazard for cancer mortality to the cumulative hazard for overall mortality (ω) using the Akaike Information Criterion. Results In each sample, increasing GCE risk scores were associated with increased cancer-specific mortality and decreased competing mortality, whereas risk scores from Cox models were associated with both increased cancer-specific mortality and competing mortality. GCE models created greater separation in the area under the curve for cancer-specific mortality versus noncancer mortality (P < .001), indicating better discriminatory ability between these events. Comparing the GCE model to Cox models of cause-specific mortality or all-cause mortality, the respective Akaike Information Criterion scores were superior (lower) in each sample: prostate cancer, 28.6 versus 35.5 versus 39.4; head and neck cancer, 21.1 versus 29.4 versus 40.2; and breast cancer, 24.6 versus 32.3 versus 50.8. Conclusion Compared with standard modeling approaches, GCE models improve stratification of elderly patients with cancer according to their risk of dying from cancer relative to overall mortality. PMID:26884579

  20. Bayesian estimation of the relative toxicity of (239)Pu and (226)Ra with dependent competing risks

    NASA Astrophysics Data System (ADS)

    Xiao, Shili

    The purpose of this dissertation research is to compare the toxicity of the alpha-emitting, bone-seeking radionuclides sp{239}Pu and sp{226}Ra, develop a model for radiation induced osteosarcomas, and analyze the survival data of beagles exposed to these radionuclides. This research integrates the knowledge of radiation protection, survival theory and methods (competing risks, maximum likelihood estimation, and Bayesian techniques), numerical integration techniques (Monte Carlo, Lattice rule and Gauss-quadrature) and object-oriented programming in C++. The outline of this research is: (1) survival data preprocessing, (2) model identification and selection, (3) introduction of FGM model, the dependent competing risk model created by Farlie, Gumbel and Morgenstern, to the study of survival data with dependent competing risks: osteosarcomas and other diseases, development of the crude density of the FGM model and construction of the likelihood function for the FGM model, (4) Bayesian estimates of the posterior marginal density of the toxicity ratio in the FGM model using several numerical integration techniques (Monte Carlo, Lattice rule and Gaussian Quadrature), (5) construction of the likelihood function for the independent competing risk model, Bayesian estimate of the posterior marginal density of toxicity ratio in the model using Monte Carlo method, which is compared with the posterior marginal densities for the toxicity ratio obtained from the FGM model, (6) Bayesian estimates of all other parameters in the FGM model using Monte Carlo method, (7) Comparison of the cumulative hazard for sp{239}Pu calculated according to the model with Nelson's cumulative hazard plot under Bayesian point estimates of parameters and the mean activity in each injection level, (8) Comparison of the toxicity of plutonium in osteosarcoma with that of radium under Bayesian point estimates of parameters an d the selected activit of 0.85 muCsbi, (7) discuss Bayesian prediction of the

  1. A Competence-Based Science Learning Framework Illustrated through the Study of Natural Hazards and Disaster Risk Reduction

    ERIC Educational Resources Information Center

    Oyao, Sheila G.; Holbrook, Jack; Rannikmäe, Miia; Pagunsan, Marmon M.

    2015-01-01

    This article proposes a competence-based learning framework for science teaching, applied to the study of "big ideas", in this case to the study of natural hazards and disaster risk reduction (NH&DRR). The framework focuses on new visions of competence, placing emphasis on nurturing connectedness and behavioral actions toward…

  2. The Learning and Competency Development of Master Teachers in Alternative High Schools for At-Risk Youth: A Case Study

    ERIC Educational Resources Information Center

    Williams, Nida W.

    2012-01-01

    This qualitative case study was designed to explore how master teachers in transfer high schools learn the competencies they perceive are required to engage at-risk students so that they persist and graduate. The study is based on the following assumptions: (1) The requisite teacher competencies can be defined and identified and, in fact,…

  3. From Reading Readiness to Reading Competence: The Role of Self-Regulation in At-Risk Children

    ERIC Educational Resources Information Center

    Smith, Leann E.; Borkowski, John G.; Whitman, Thomas L.

    2008-01-01

    This study investigated how self-regulation contributes to the development of reading competence in an at-risk sample of 157 children born to adolescent mothers. It was hypothesized that reading readiness at age 5 would shape self-regulation at age 10, which in turn would influence reading competence at age 14. Based on structural equation…

  4. Conduct problems and level of social competence in Head Start children: prevalence, pervasiveness, and associated risk factors.

    PubMed

    Webster-Stratton, C; Hammond, M

    1998-06-01

    The purpose of the current project was to determine the prevalence of conduct problems, low social competence, and associated risk factors in a sample of 4-year-old low-income children (N = 426) from 64 Head Start classrooms in the Seattle area. Conduct problems and social competence were assessed based on a combination of teacher reports, parent reports, and independent observations of children interacting with peers in the classroom and with parents at home. We examined the relative contribution of a variety of risk factors, including maternal history and socioeconomic background, current levels of stress and social support, mothers' emotional state, and parenting competence in relation to "pervasive" (i.e., at home and school) and "nonpervasive" conduct problems and low social competence. Findings indicated similar risk factors for conduct problems and for low social competence, with an ordered increase in the number of risk factors from normal to "nonpervasive" to "pervasive" groups. Harshness of parenting style (i.e., slapping, hitting, yelling) significantly distinguished between the three groups for low social competence and conduct problems. Positive affect, praise, and physical warmth from mothers were positively related to social competence but unrelated to conduct problems. PMID:11324301

  5. Conduct problems and level of social competence in Head Start children: prevalence, pervasiveness, and associated risk factors.

    PubMed

    Webster-Stratton, C; Hammond, M

    1998-06-01

    The purpose of the current project was to determine the prevalence of conduct problems, low social competence, and associated risk factors in a sample of 4-year-old low-income children (N = 426) from 64 Head Start classrooms in the Seattle area. Conduct problems and social competence were assessed based on a combination of teacher reports, parent reports, and independent observations of children interacting with peers in the classroom and with parents at home. We examined the relative contribution of a variety of risk factors, including maternal history and socioeconomic background, current levels of stress and social support, mothers' emotional state, and parenting competence in relation to "pervasive" (i.e., at home and school) and "nonpervasive" conduct problems and low social competence. Findings indicated similar risk factors for conduct problems and for low social competence, with an ordered increase in the number of risk factors from normal to "nonpervasive" to "pervasive" groups. Harshness of parenting style (i.e., slapping, hitting, yelling) significantly distinguished between the three groups for low social competence and conduct problems. Positive affect, praise, and physical warmth from mothers were positively related to social competence but unrelated to conduct problems.

  6. Sociodemographic risk, developmental competence, and PTSD symptoms in young children exposed to interpersonal trauma in early life.

    PubMed

    Enlow, Michelle Bosquet; Blood, Emily; Egeland, Byron

    2013-12-01

    Young children are disproportionately exposed to interpersonal trauma (maltreatment, witnessing intimate partner violence [IPV]) and appear particularly susceptible to negative sequelae. Little is known about the factors influencing vulnerability to traumatic stress responses and other negative outcomes in early life. This study examined associations among interpersonal trauma exposure, sociodemographic risk, developmental competence, and posttraumatic stress disorder (PTSD) symptoms in 200 children assessed from birth to first grade via standardized observations, record reviews, and maternal and teacher interviews. More severe PTSD symptoms were predicted by greater trauma exposure (r = .43), greater sociodemographic risk (r = .22), and lower developmental competence (rs=−.31 and −.54 for preschool and school-age developmental competence, respectively). Developmental competence partially mediated the association between trauma exposure and symptoms. Trauma exposure fully mediated the association between sociodemographic risk and symptoms. Neither sociodemographic risk nor developmental competence moderated trauma exposure effects on symptoms. The findings suggest that (a)exposure to maltreatment and IPV has additive effects on posttraumatic stress risk in early life, (b) associations between sociodemographic adversity and poor mental health may be attributable to increased trauma exposure in disadvantaged populations, and (c) early exposures have a negative cascade effect on developmental competence and mental health.

  7. Proportional hazards model for competing risks data with missing cause of failure.

    PubMed

    Hyun, Seunggeun; Lee, Jimin; Sun, Yanqing

    2012-07-01

    We consider the semiparametric proportional hazards model for the cause-specific hazard function in analysis of competing risks data with missing cause of failure. The inverse probability weighted equation and augmented inverse probability weighted equation are proposed for estimating the regression parameters in the model, and their theoretical properties are established for inference. Simulation studies demonstrate that the augmented inverse probability weighted estimator is doubly robust and the proposed method is appropriate for practical use. The simulations also compare the proposed estimators with the multiple imputation estimator of Lu and Tsiatis (2001). The application of the proposed method is illustrated using data from a bone marrow transplant study. PMID:22468017

  8. A competing risk analysis of sequential complication development in Asian type 2 diabetes mellitus patients

    PubMed Central

    Cheng, Li-Jen; Chen, Jeng-Huei; Lin, Ming-Yen; Chen, Li-Chia; Lao, Chun-Huan; Luh, Hsing; Hwang, Shang-Jyh

    2015-01-01

    This retrospective cohort study investigated the progression risk of sequential complication in Asian type 2 diabetes (T2D) patients using the Taiwan Pay-for-Performance Diabetes Registry and claim data from November 2003 to February 2009. 226,310 adult T2D patients without complication were followed from diagnosis to complications, including myocardial infarction (MI), other ischemic heart disease (IHD), congestive heart failure (CHF), stroke, chronic kidney disease (CKD), retinopathy, amputation, death or to the end of study. Cumulative incidences (CIs) of first and second complications were analyzed in 30 and 4 years using the cumulative incidence competing risk method. IHD (29.8%), CKD (24.5%) and stroke (16.0%) are the most common first complications. The further development of T2D complications depends on a patient’s existing complication profiles. Patients who initially developed cardiovascular complications had a higher risk (9.2% to 24.4%) of developing IHD or CKD, respectively. All-cause mortality was the most likely consequence for patients with a prior MI (12.0%), so as stroke in patients with a prior MI (10.8%) or IHD (8.9%). Patients with CKD had higher risk of developing IHD (16.3%), stroke (8.9%) and all-cause mortality (8.7%) than end-stage renal disease (4.0%). Following an amputation, patients had a considerable risk of all-cause mortality (42.1%). PMID:26507664

  9. A competing risk analysis of sequential complication development in Asian type 2 diabetes mellitus patients.

    PubMed

    Cheng, Li-Jen; Chen, Jeng-Huei; Lin, Ming-Yen; Chen, Li-Chia; Lao, Chun-Huan; Luh, Hsing; Hwang, Shang-Jyh

    2015-01-01

    This retrospective cohort study investigated the progression risk of sequential complication in Asian type 2 diabetes (T2D) patients using the Taiwan Pay-for-Performance Diabetes Registry and claim data from November 2003 to February 2009. 226,310 adult T2D patients without complication were followed from diagnosis to complications, including myocardial infarction (MI), other ischemic heart disease (IHD), congestive heart failure (CHF), stroke, chronic kidney disease (CKD), retinopathy, amputation, death or to the end of study. Cumulative incidences (CIs) of first and second complications were analyzed in 30 and 4 years using the cumulative incidence competing risk method. IHD (29.8%), CKD (24.5%) and stroke (16.0%) are the most common first complications. The further development of T2D complications depends on a patient's existing complication profiles. Patients who initially developed cardiovascular complications had a higher risk (9.2% to 24.4%) of developing IHD or CKD, respectively. All-cause mortality was the most likely consequence for patients with a prior MI (12.0%), so as stroke in patients with a prior MI (10.8%) or IHD (8.9%). Patients with CKD had higher risk of developing IHD (16.3%), stroke (8.9%) and all-cause mortality (8.7%) than end-stage renal disease (4.0%). Following an amputation, patients had a considerable risk of all-cause mortality (42.1%). PMID:26507664

  10. Vertical modelling: Analysis of competing risks data with missing causes of failure.

    PubMed

    Nicolaie, M A; van Houwelingen, H C; Putter, H

    2015-12-01

    We propose vertical modelling as a natural approach to the problem of analysis of competing risks data when failure types are missing for some individuals. Under a natural missing-at-random assumption for these missing failure types, we use the observed data likelihood to estimate its parameters and show that the all-cause hazard and the relative hazards appearing in vertical modelling are indeed key quantities of this likelihood. This fact has practical implications in that it suggests vertical modelling as a simple and attractive method of analysis in competing risks with missing causes of failure; all individuals are used in estimating the all-cause hazard and only those with non-missing cause of failure for relative hazards. The relative hazards also appear in a multiple imputation approach to the same problem proposed by Lu and Tsiatis and in the EM algorithm. We compare the vertical modelling approach with the method of Goetghebeur and Ryan for a breast cancer data set, highlighting the different aspects they contribute to the data analysis. PMID:22179822

  11. A review of methods to estimate cause-specific mortality in presence of competing risks

    USGS Publications Warehouse

    Heisey, Dennis M.; Patterson, Brent R.

    2006-01-01

    Estimating cause-specific mortality is often of central importance for understanding the dynamics of wildlife populations. Despite such importance, methodology for estimating and analyzing cause-specific mortality has received little attention in wildlife ecology during the past 20 years. The issue of analyzing cause-specific, mutually exclusive events in time is not unique to wildlife. In fact, this general problem has received substantial attention in human biomedical applications within the context of biostatistical survival analysis. Here, we consider cause-specific mortality from a modern biostatistical perspective. This requires carefully defining what we mean by cause-specific mortality and then providing an appropriate hazard-based representation as a competing risks problem. This leads to the general solution of cause-specific mortality as the cumulative incidence function (CIF). We describe the appropriate generalization of the fully nonparametric staggered-entry Kaplan–Meier survival estimator to cause-specific mortality via the nonparametric CIF estimator (NPCIFE), which in many situations offers an attractive alternative to the Heisey–Fuller estimator. An advantage of the NPCIFE is that it lends itself readily to risk factors analysis with standard software for Cox proportional hazards model. The competing risks–based approach also clarifies issues regarding another intuitive but erroneous "cause-specific mortality" estimator based on the Kaplan–Meier survival estimator and commonly seen in the life sciences literature.

  12. Confidence interval procedures for system reliability and applications to competing risks models.

    PubMed

    Hong, Yili; Meeker, William Q

    2014-04-01

    System reliability depends on the reliability of the system's components and the structure of the system. For example, in a competing risks model, the system fails when the weakest component fails. The reliability function and the quantile function of a complicated system are two important metrics for characterizing the system's reliability. When there are data available at the component level, the system reliability can be estimated by using the component level information. Confidence intervals (CIs) are needed to quantify the statistical uncertainty in the estimation. Obtaining system reliability CI procedures with good properties is not straightforward, especially when the system structure is complicated. In this paper, we develop a general procedure for constructing a CI for the system failure-time quantile function by using the implicit delta method. We also develop general procedures for constructing a CI for the cumulative distribution function (cdf) of the system. We show that the recommended procedures are asymptotically valid and have good statistical properties. We conduct simulations to study the finite-sample coverage properties of the proposed procedures and compare them with existing procedures. We apply the proposed procedures to three applications; two applications in competing risks models and an application with a k-out-of-s system. The paper concludes with some discussion and an outline of areas for future research.

  13. Sociodemographic Risk, Developmental Competence, and PTSD Symptoms in Young Children Exposed to Interpersonal Trauma in Early Life

    PubMed Central

    Enlow, Michelle Bosquet; Blood, Emily; Egeland, Byron

    2014-01-01

    Children under age six years are disproportionately exposed to interpersonal trauma, including maltreatment and witnessing intimate partner violence (IPV), and may be particularly susceptible to negative sequelae. However, young children have generally been neglected from trauma research; thus, little is known about the factors influencing vulnerability to traumatic stress responses and other negative outcomes in early life. This study examined associations among interpersonal trauma exposure, sociodemographic risk, developmental competence, and posttraumatic stress disorder (PTSD) symptoms in 200 children assessed prospectively from birth to 1st grade via home and laboratory observations, record reviews, and maternal and teacher interviews. Greater trauma exposure and sociodemographic risk and lower developmental competence predicted more severe PTSD symptoms. Developmental competence partially mediated the association between exposures and symptoms. Trauma exposure fully mediated the association between sociodemographic risk and symptoms. Neither sociodemographic risk nor developmental competence moderated trauma exposure effects on symptoms. The findings suggest that (a) exposure to maltreatment and IPV has additive effects on posttraumatic stress risk in early life, (b) associations between sociodemographic adversity and poor mental health may be attributable to increased trauma exposure in disadvantaged populations, and (c) early exposures have a negative cascade effect on developmental competence and child mental health. PMID:24490247

  14. Survival analysis in total joint replacement: an alternative method of accounting for the presence of competing risk.

    PubMed

    Fennema, P; Lubsen, J

    2010-05-01

    Survival analysis is an important tool for assessing the outcome of total joint replacement. The Kaplan-Meier method is used to estimate the incidence of revision of a prosthesis over time, but does not account appropriately for competing events which preclude revision. In the presence of competing death, this method will lead to statistical bias and the curve will lose its interpretability. A valid comparison of survival results between studies using the method is impossible without accounting for different rates of competing events. An alternative and easily applicable approach, the cumulative incidence of competing risk, is proposed. Using three simulated data sets and realistic data from a cohort of 406 consecutive cementless total hip prostheses, followed up for a minimum of ten years, both approaches were compared and the magnitude of potential bias was highlighted. The Kaplan-Meier method overestimated the incidence of revision by almost 4% (60% relative difference) in the simulations and more than 1% (31.3% relative difference) in the realistic data set. The cumulative incidence of competing risk approach allows for appropriate accounting of competing risk and, as such, offers an improved ability to compare survival results across studies.

  15. Competing Risks Data Analysis with High-dimensional Covariates: An Application in Bladder Cancer

    PubMed Central

    Tapak, Leili; Saidijam, Massoud; Sadeghifar, Majid; Poorolajal, Jalal; Mahjub, Hossein

    2015-01-01

    Analysis of microarray data is associated with the methodological problems of high dimension and small sample size. Various methods have been used for variable selection in high-dimension and small sample size cases with a single survival endpoint. However, little effort has been directed toward addressing competing risks where there is more than one failure risks. This study compared three typical variable selection techniques including Lasso, elastic net, and likelihood-based boosting for high-dimensional time-to-event data with competing risks. The performance of these methods was evaluated via a simulation study by analyzing a real dataset related to bladder cancer patients using time-dependent receiver operator characteristic (ROC) curve and bootstrap .632+ prediction error curves. The elastic net penalization method was shown to outperform Lasso and boosting. Based on the elastic net, 33 genes out of 1381 genes related to bladder cancer were selected. By fitting to the Fine and Gray model, eight genes were highly significant (P < 0.001). Among them, expression of RTN4, SON, IGF1R, SNRPE, PTGR1, PLEK, and ETFDH was associated with a decrease in survival time, whereas SMARCAD1 expression was associated with an increase in survival time. This study indicates that the elastic net has a higher capacity than the Lasso and boosting for the prediction of survival time in bladder cancer patients. Moreover, genes selected by all methods improved the predictive power of the model based on only clinical variables, indicating the value of information contained in the microarray features. PMID:25907251

  16. Competing Risk Analysis for Evaluation of Dalteparin Versus Unfractionated Heparin for Venous Thromboembolism in Medical-Surgical Critically Ill Patients

    PubMed Central

    Li, Guowei; Cook, Deborah J.; Levine, Mitchell A.H.; Guyatt, Gordon; Crowther, Mark; Heels-Ansdell, Diane; Holbrook, Anne; Lamontagne, Francois; Walter, Stephen D.; Ferguson, Niall D.; Finfer, Simon; Arabi, Yaseen M.; Bellomo, Rinaldo; Cooper, D. Jamie; Thabane, Lehana

    2015-01-01

    Abstract Failure to recognize the presence of competing risk or to account for it may result in misleading conclusions. We aimed to perform a competing risk analysis to assess the efficacy of the low molecular weight heparin dalteparin versus unfractionated heparin (UFH) in venous thromboembolism (VTE) in medical-surgical critically ill patients, taking death as a competing risk. This was a secondary analysis of a prospective randomized study of the Prophylaxis for Thromboembolism in Critical Care Trial (PROTECT) database. A total of 3746 medical-surgical critically ill patients from 67 intensive care units (ICUs) in 6 countries receiving either subcutaneous UFH 5000 IU twice daily (n = 1873) or dalteparin 5000 IU once daily plus once-daily placebo (n = 1873) were included for analysis. A total of 205 incident proximal leg deep vein thromboses (PLDVT) were reported during follow-up, among which 96 were in the dalteparin group and 109 were in the UFH group. No significant treatment effect of dalteparin on PLDVT compared with UFH was observed in either the competing risk analysis or standard survival analysis (also known as cause-specific analysis) using multivariable models adjusted for APACHE II score, history of VTE, need for vasopressors, and end-stage renal disease: sub-hazard ratio (SHR) = 0.92, 95% confidence interval (CI): 0.70–1.21, P-value = 0.56 for the competing risk analysis; hazard ratio (HR) = 0.92, 95% CI: 0.68–1.23, P-value = 0.57 for cause-specific analysis. Dalteparin was associated with a significant reduction in risk of pulmonary embolism (PE): SHR = 0.54, 95% CI: 0.31–0.94, P-value = 0.02 for the competing risk analysis; HR = 0.51, 95% CI: 0.30–0.88, P-value = 0.01 for the cause-specific analysis. Two additional sensitivity analyses using the treatment variable as a time-dependent covariate and using as-treated and per-protocol approaches demonstrated similar findings. This competing risk analysis

  17. Competing Risk Analysis for Evaluation of Dalteparin Versus Unfractionated Heparin for Venous Thromboembolism in Medical-Surgical Critically Ill Patients.

    PubMed

    Li, Guowei; Cook, Deborah J; Levine, Mitchell A H; Guyatt, Gordon; Crowther, Mark; Heels-Ansdell, Diane; Holbrook, Anne; Lamontagne, Francois; Walter, Stephen D; Ferguson, Niall D; Finfer, Simon; Arabi, Yaseen M; Bellomo, Rinaldo; Cooper, D Jamie; Thabane, Lehana

    2015-09-01

    Failure to recognize the presence of competing risk or to account for it may result in misleading conclusions. We aimed to perform a competing risk analysis to assess the efficacy of the low molecular weight heparin dalteparin versus unfractionated heparin (UFH) in venous thromboembolism (VTE) in medical-surgical critically ill patients, taking death as a competing risk.This was a secondary analysis of a prospective randomized study of the Prophylaxis for Thromboembolism in Critical Care Trial (PROTECT) database. A total of 3746 medical-surgical critically ill patients from 67 intensive care units (ICUs) in 6 countries receiving either subcutaneous UFH 5000 IU twice daily (n = 1873) or dalteparin 5000 IU once daily plus once-daily placebo (n = 1873) were included for analysis.A total of 205 incident proximal leg deep vein thromboses (PLDVT) were reported during follow-up, among which 96 were in the dalteparin group and 109 were in the UFH group. No significant treatment effect of dalteparin on PLDVT compared with UFH was observed in either the competing risk analysis or standard survival analysis (also known as cause-specific analysis) using multivariable models adjusted for APACHE II score, history of VTE, need for vasopressors, and end-stage renal disease: sub-hazard ratio (SHR) = 0.92, 95% confidence interval (CI): 0.70-1.21, P-value = 0.56 for the competing risk analysis; hazard ratio (HR) = 0.92, 95% CI: 0.68-1.23, P-value = 0.57 for cause-specific analysis. Dalteparin was associated with a significant reduction in risk of pulmonary embolism (PE): SHR = 0.54, 95% CI: 0.31-0.94, P-value = 0.02 for the competing risk analysis; HR = 0.51, 95% CI: 0.30-0.88, P-value = 0.01 for the cause-specific analysis. Two additional sensitivity analyses using the treatment variable as a time-dependent covariate and using as-treated and per-protocol approaches demonstrated similar findings.This competing risk analysis yields no

  18. Competing Risk Analysis for Evaluation of Dalteparin Versus Unfractionated Heparin for Venous Thromboembolism in Medical-Surgical Critically Ill Patients.

    PubMed

    Li, Guowei; Cook, Deborah J; Levine, Mitchell A H; Guyatt, Gordon; Crowther, Mark; Heels-Ansdell, Diane; Holbrook, Anne; Lamontagne, Francois; Walter, Stephen D; Ferguson, Niall D; Finfer, Simon; Arabi, Yaseen M; Bellomo, Rinaldo; Cooper, D Jamie; Thabane, Lehana

    2015-09-01

    Failure to recognize the presence of competing risk or to account for it may result in misleading conclusions. We aimed to perform a competing risk analysis to assess the efficacy of the low molecular weight heparin dalteparin versus unfractionated heparin (UFH) in venous thromboembolism (VTE) in medical-surgical critically ill patients, taking death as a competing risk.This was a secondary analysis of a prospective randomized study of the Prophylaxis for Thromboembolism in Critical Care Trial (PROTECT) database. A total of 3746 medical-surgical critically ill patients from 67 intensive care units (ICUs) in 6 countries receiving either subcutaneous UFH 5000 IU twice daily (n = 1873) or dalteparin 5000 IU once daily plus once-daily placebo (n = 1873) were included for analysis.A total of 205 incident proximal leg deep vein thromboses (PLDVT) were reported during follow-up, among which 96 were in the dalteparin group and 109 were in the UFH group. No significant treatment effect of dalteparin on PLDVT compared with UFH was observed in either the competing risk analysis or standard survival analysis (also known as cause-specific analysis) using multivariable models adjusted for APACHE II score, history of VTE, need for vasopressors, and end-stage renal disease: sub-hazard ratio (SHR) = 0.92, 95% confidence interval (CI): 0.70-1.21, P-value = 0.56 for the competing risk analysis; hazard ratio (HR) = 0.92, 95% CI: 0.68-1.23, P-value = 0.57 for cause-specific analysis. Dalteparin was associated with a significant reduction in risk of pulmonary embolism (PE): SHR = 0.54, 95% CI: 0.31-0.94, P-value = 0.02 for the competing risk analysis; HR = 0.51, 95% CI: 0.30-0.88, P-value = 0.01 for the cause-specific analysis. Two additional sensitivity analyses using the treatment variable as a time-dependent covariate and using as-treated and per-protocol approaches demonstrated similar findings.This competing risk analysis yields no

  19. Connection between competence, usability, environment and risk of falls in elderly adults

    PubMed Central

    Leiva-Caro, José Alex; Salazar-González, Bertha Cecilia; Gallegos-Cabriales, Esther Carlota; Gómez-Meza, Marco Vinicio; Hunter, Kathleen F.

    2015-01-01

    Objective: to determine connections between competence, usability, environment and risk of falls in elderly adults. Method: correlational descriptive study, 123 elderly adults, both male and female, aged 70 years and older were included. Data was collected via the Tinetti Scale, CESD-7 Scale, Montreal Cognitive Assessment, Usability Questionnaire on Housing and Housing Enabler; and sociodemographic and health background certificate data. For data analysis, descriptive and inferential statistics were used, multivariate linear and logistic regression models were adjusted. Results: 42.0% of the elderly adults had presented with falls, with a higher prevalence in women, and in the group of 70-75 years. The physical environment of the house, gait, and usability were set as risk factors for falls. A negative relationship between usability and depressive symptoms, cognitive health, balance, gait, the social and physical environment was found, p <0.05; and a strong positive correlation between walking and balance, p <0.05. Conclusion: this study helps to better understand the phenomenon of falling, to find a connection between usability with the risk of falls, and other variables. PMID:26626006

  20. Resilience and risk competence in schools: theory/knowledge and international application in project rebound.

    PubMed

    Brown, Joel H; Jean-Marie, Gaetane; Beck, Jerome

    2010-01-01

    Despite a 50-year interdisciplinary and longitudinal research legacy--showing that nearly 80% of young people considered most "at risk" thrive by midlife-only recently have practitioners/researchers engaged in the explicit, prospective facilitation of "resilience" in educational settings. Here, theory/knowledge distinguishing and extending risk and resilience from its risk-based social history to resilience's normative occurrence leads to the first known international and prospective application of resilience in school-based drug education, Project REBOUND [resilience-bound]. It will be implemented as a controlled pilot study, first in Germany, then expand to the United States, as well as other parts of Europe. With evaluation occurring throughout, the goal is to enhance the quality of drug decisions among young people, as well as support their overall competence-based learning and development throughout school. With limitations and underlying psychological mechanisms discussed, it is concluded Project REBOUND offers promising potential for supporting positive drug decisions as well as youth learning and development. PMID:21381462

  1. Competing impact of excess weight versus cardiorespiratory fitness on cardiovascular risk.

    PubMed

    Diaz, Vanessa A; Player, Marty S; Mainous, Arch G; Carek, Peter J; Geesey, Mark E

    2006-12-01

    Obesity is a risk factor for cardiovascular disease, whereas high cardiorespiratory fitness (CRF) is cardioprotective. This study evaluated the competing effect of weight and fitness on biomarkers of cardiovascular risk in a nationally representative sample of 2,112 adults (20 to 49 years of age; body mass index [BMI] > or =18.5 kg/m(2)) without previously diagnosed cardiovascular disease from the National Health and Nutrition Examination Survey 1999 to 2002. CRF levels were assigned using age- and gender-specific reference points of estimated maximal oxygen consumption calculated from submaximal graded exercise treadmill testing. CRF was also categorized by sample-specific tertiles of maximal oxygen consumption. Weight was categorized using BMI. Fasting insulin level >12.2 mU/L, C-reactive protein level > or =3.0 mg/L, and total cholesterol/high-density lipoprotein ratio (TC/HDL) >5 characterized increased cardiovascular risk. CRF and BMI were independently associated with increased fasting insulin and C-reactive protein (p <0.05). When patients with low, moderate, and high CRF were further stratified as normal, overweight, or obese, weight remained significantly associated with increased fasting insulin, C-reactive protein, and TC/HDL (p <0.001), but CRF did not. Logistic regressions evaluating increased fasting insulin, C-reactive protein, and TC/HDL demonstrated no significant differences in overweight/obese patients by CRF level after adjustment for other factors. Significant differences were present between normal-weight and overweight or obese patients regardless of fitness level. Analyses using tertiles of CRF yielded similar results. In conclusion, patients who are "fat but fit" require weight-loss interventions to improve their cardiovascular risk profiles. Future interventions should emphasize weight control, even for those with high CRF.

  2. Examining the role of methamphetamine in permanency: A competing risks analysis of reunification, guardianship, and adoption.

    PubMed

    Akin, Becci A; Brook, Jody; Lloyd, Margaret H

    2015-03-01

    Parental methamphetamine use has drawn significant attention in recent years. Despite prior research that shows that parental substance abuse is a risk factor for lengthy foster care stay, little is known about the effect of specific types of substance use on permanency. This study sought to compare the impact of parental methamphetamine use to alcohol use, other drug use, and polysubstance use on the timing of 3 types of permanency: reunification, guardianship, and adoption. Using an entry cohort of 16,620 children who had entered foster care during a 5-year period, competing risks event history models were conducted for each permanency type. Findings showed that, after controlling for several case characteristics, parent illicit drug use significantly impacted the timing of the 3 types of permanency, but alcohol use did not. Methamphetamine, other drug, and polysubstance with methamphetamine use were associated with lower rates of reunification and higher rates of adoption. Guardianship was also predicted by other drug and polysubstance use without methamphetamine; however, methamphetamine use was not associated with guardianship. Notably, the methamphetamine groups comprised the youngest children and had the shortest median time to adoption. Results suggest that type of parental substance use is predictive of permanency exits and that parental illicit drug use may require tailored strategies for improving permanency outcomes. Further implications of the findings are discussed.

  3. [Legalization and dissolution of consensual unions: an example of log-linear models used to estimate models of competing risk].

    PubMed

    Gomez De Leon, J

    1998-01-01

    "This is a mainly methodological work: a generalization of the so-called proportional risk models to cases of multiple and competing risks.... Proportional risk models are an extension of the methodology implied in calculating mortality tables, where the risk function is made to depend on some variables (covariables), as in a regression model.... Life-table methodology has been...an essential instrument in demographic calculus and analysis." The author uses the proposed methods to analyze the determinants of the legalization and dissolution of consensual unions in Mexico. (EXCERPT) PMID:12294953

  4. Cumulative Risk, Negative Emotionality, and Emotion Regulation as Predictors of Social Competence in Transition to School: A Mediated Moderation Model

    ERIC Educational Resources Information Center

    Chang, Hyein; Shelleby, Elizabeth C.; Cheong, JeeWon; Shaw, Daniel S.

    2012-01-01

    The goals of this study were to examine the additive and interactive effects of cumulative risk and child negative emotionality on children's social competence in the transition from preschool to school and to test whether these associations were mediated by child emotion regulation within a sample of 310 low-income, ethnically diverse boys.…

  5. Sensation Seeking: A Potential Factor Influencing Perceived Risk and Perceived Competence in an Introductory Scuba Diving Course

    ERIC Educational Resources Information Center

    Morgan, Cass

    2009-01-01

    This study examined the relationship between the sensation-seeking personality trait to changes in perceived risk and perceived competence during an adventure experience. Participants (n = 57) were enrolled in a 14-week introductory scuba diving course offered at a university in eastern North Carolina in 2006. The data was analyzed using a…

  6. Environmental risk assessment of replication competent viral vectors applied in clinical trials: potential effects of inserted sequences.

    PubMed

    van den Akker, Eric; van der Vlugt, Cecile J B; Bleijs, Diederik A; Bergmans, Hans E

    2013-12-01

    Risk assessments of clinical applications involving genetically modified viral vectors are carried out according to general principles that are implemented in many national and regional legislations, e.g., in Directive 2001/18/EC of the European Union. Recent developments in vector design have a large impact on the concepts that underpin the risk assessments of viral vectors that are used in clinical trials. The use of (conditionally) replication competent viral vectors (RCVVs) may increase the likelihood of the exposure of the environment around the patient, compared to replication defective viral vectors. Based on this assumption we have developed a methodology for the environmental risk assessment of replication competent viral vectors, which is presented in this review. Furthermore, the increased likelihood of exposure leads to a reevaluation of what would constitute a hazardous gene product in viral vector therapies, and a keen interest in new developments in the inserts used. One of the trends is the use of inserts produced by synthetic biology. In this review the implications of these developments for the environmental risk assessment of RCVVs are highlighted, with examples from current clinical trials. The conclusion is drawn that RCVVs, notwithstanding their replication competency, can be applied in an environmentally safe way, in particular if adequate built-in safeties are incorporated, like conditional replication competency, as mitigating factors to reduce adverse environmental effects that could occur.

  7. Cumulative Risk, the Mother-Child Relationship, and Social-Emotional Competence in Latino Head Start Children

    ERIC Educational Resources Information Center

    Martí, Maria; Bonillo, Albert; Jané, Maria Claustre; Fisher, Elisa M.; Duch, Helena

    2016-01-01

    Research Findings: Supportive mother-child interactions promote the development of social-emotional competence. Poverty and other associated psychosocial risk factors have a negative impact on mother-child interaction. In spite of Latino children being disproportionately represented among children living in poverty, research on mother-child…

  8. A consistent NPMLE of the joint distribution function with competing risks data under the dependent masking and right-censoring model.

    PubMed

    Li, Jiahui; Yu, Qiqing

    2016-01-01

    Dinse (Biometrics, 38:417-431, 1982) provides a special type of right-censored and masked competing risks data and proposes a non-parametric maximum likelihood estimator (NPMLE) and a pseudo MLE of the joint distribution function [Formula: see text] with such data. However, their asymptotic properties have not been studied so far. Under the extention of either the conditional masking probability (CMP) model or the random partition masking (RPM) model (Yu and Li, J Nonparametr Stat 24:753-764, 2012), we show that (1) Dinse's estimators are consistent if [Formula: see text] takes on finitely many values and each point in the support set of [Formula: see text] can be observed; (2) if the failure time is continuous, the NPMLE is not uniquely determined, and the standard approach (which puts weights only on one element in each observed set) leads to an inconsistent NPMLE; (3) in general, Dinse's estimators are not consistent even under the discrete assumption; (4) we construct a consistent NPMLE. The consistency is given under a new model called dependent masking and right-censoring model. The CMP model and the RPM model are indeed special cases of the new model. We compare our estimator to Dinse's estimators through simulation and real data. Simulation study indicates that the consistent NPMLE is a good approximation to the underlying distribution for moderate sample sizes. PMID:25160694

  9. Incidence and Risk Factors of Thromboembolism with Multiple Myeloma in the Presence of Death as a Competing Risk: An Empirical Comparison of Statistical Methodologies.

    PubMed

    Brown, Joshua D; Adams, Val R

    2016-01-01

    Multiple myeloma (MM) has an inherent high risk of thromboembolic events associated with patient as well as disease- and treatment-related factors. Previous studies have assessed the association of MM-related thromboembolism using "traditional" Kaplan-Meier (KM) and/or Cox proportional hazard (PH) regression. In the presence of high incidence of death, as would be the case in cancer patients with advanced age, these statistical models will produce bias estimates. Instead, a competing risk framework should be used. This study assessed the baseline patient demographic and clinical characteristics associated with MM-related thromboembolism and compared the cumulative incidence and the measures of association obtained using each statistical approach. The cumulative incidence of thromboembolism was 9.2% using the competing risk framework and nearly 12% using the KM approach. Bias in the measures of covariate risk associations was highest for factors related to risk of death such as increased age (75% bias) and severe liver disease (50%) for the Cox PH model compared to the competing risk model. These results show that correct specification of statistical techniques can have a large impact on the results obtained. PMID:27417604

  10. SCHIP premiums, enrollment, and expenditures: a two state, competing risk analysis.

    PubMed

    Marton, James; Ketsche, Patricia G; Zhou, Mei

    2010-07-01

    Faced with state budget troubles, policymakers may introduce or increase State Children's Health Insurance Program (SCHIP) premiums for children in the highest program income eligibility categories. In this paper we compare the responses of SCHIP recipients in a state (Kentucky) that introduced SCHIP premiums for the first time at the end of 2003 with the responses of recipients in a state (Georgia) that increased existing SCHIP premiums in mid-2004. We start with a theoretical examination of how these different policies create different changes to family budget constraints and produce somewhat different financial incentives for recipients. Next we empirically model the impact of these policies using a competing risk approach to differentiate exits due to transfers to other eligibility categories of public coverage from exiting the public health insurance system. In both states we find a short-run increase in the likelihood that children transfer to lower- income eligibility/lower-premium categories of SCHIP. We also find a short-run increase in the rate at which children transfer from SCHIP to Medicaid in Kentucky, which is consistent with our theoretical model. These findings have important financial implications for state budgets, as the matching rates and premium levels are different for different eligibility categories of public coverage.

  11. Transferable Competences of Young People with a High Dropout Risk in Vocational Training in Germany

    ERIC Educational Resources Information Center

    Frey, Andreas; Balzer, Lars; Ruppert, Jean-Jacques

    2014-01-01

    This paper examines whether the subjective beliefs on their competences of 409 trainees in machinery, sales, and logistics constitute a reliable and valid way to measure transferable competences. The analysis of results attributes satisfactory to good reliability values to the assessment procedure. Furthermore, it could be shown that young people…

  12. Estimation of Ten-Year Survival of Patients with Pulmonary Tuberculosis Based on the Competing Risks Model in Iran

    PubMed Central

    Kazempour-Dizaji, Mehdi; Tabarsi, Payam; Zayeri, Farid

    2016-01-01

    Background: Tuberculosis (TB) is a chronic bacterial disease, which despite the presence of effective drug strategies, still remains a serious health problem worldwide. Estimation of survival rate is an appropriate indicator for prognosis in patients with pulmonary TB. Therefore, this research was designed with the aim of accurate estimation of the survival of patients by taking both the death event and relapse into consideration. Materials and Methods: Based on a retrospective cohort study, information of 2,299 patients with pulmonary TB that had been referred to and treated in Masih Daneshvari Hospital from 2005 to 2015 was reviewed. To estimate the survival of patients with pulmonary TB, the competing risks model, which considered death and relapse as competing events, was used. In addition, the effect of factors affecting the cumulative incidence function (CIF) of death event and relapse was also examined. Results: The effect of risk factors on the CIF of death events and relapse showed that patients’ age, marital status, contact with TB patients, adverse effect of drugs, imprisonment and HIV positivity were factors that affected the CIF of death. Meanwhile, sex, marital status, imprisonment and HIV positivity were factors affecting the CIF of relapse (P <0.05). Considering death and relapse as competing events, survival estimation in pulmonary TB patients showed that survival in this group of patients in the first, third, fifth and tenth year after treatment was 39%, 14%, 7% and 0%, respectively. Conclusion: The use of competing risks model in survival analysis of patients with pulmonary TB with consideration of competing events, enables more accurate estimation of survival. PMID:27403177

  13. Risk Factors for Reporting Poor Cultural Competency Among Patients with Diabetes in Safety-Net Clinics

    PubMed Central

    Seligman, Hilary K.; Fernandez, Alicia; Stern, Rachel J.; Weech-Maldonado, Robert; Quan, Judy; Jacobs, Elizabeth A.

    2012-01-01

    Background The Consumer Assessment of Healthcare Providers and Systems Cultural Competency (CAHPS-CC) Item Set assesses patient perceptions of aspects of the cultural competence of their health care. Objective To determine characteristics of patients who identify the care they receive as less culturally competent Research Design Cross-sectional survey consisting of face-to-face interviews Subjects Safety-net population of patients with type 2 diabetes (n=600) receiving ongoing primary care Measures Participants completed the CAHPS-CC and answered questions about their race/ethnicity, gender, age, education, health status, depressive symptoms, insurance coverage, English proficiency, duration of relationship with primary care provider, and co-morbidities. Results In adjusted models, depressive symptoms were significantly associated with poor cultural competency in the Doctor Communication – Positive Behaviors domain (OR 1.73, 95%CI 1.11, 2.69). African-Americans were less likely than Whites to report poor cultural competence in the Doctor Communication – Positive Behaviors domain (OR 0.52, 0.28–0.97). Participants who reported a longer relationship (≥3 years) with their primary care provider were less likely to report poor cultural competence in the Doctor Communication – Health Promotion (OR 0.35, 0.21–0.60) and Trust domains (OR 0.4, 0.24–0.67), while participants with lower educational attainment were less likely to report poor cultural competence in the Trust domain (OR 0.51, 0.30–0.86). Overall, however, sociodemographic and clinical differences in reports of poor cultural competence were insignificant or inconsistent across the various domains of cultural competence examined. Conclusions Cultural competence interventions in safety-net settings should be implemented across populations, rather than being narrowly focused on specific sociodemographic or clinical groups. PMID:22895232

  14. Competing risk models in reliability systems, a weibull distribution model with bayesian analysis approach

    NASA Astrophysics Data System (ADS)

    Iskandar, Ismed; Satria Gondokaryono, Yudi

    2016-02-01

    In reliability theory, the most important problem is to determine the reliability of a complex system from the reliability of its components. The weakness of most reliability theories is that the systems are described and explained as simply functioning or failed. In many real situations, the failures may be from many causes depending upon the age and the environment of the system and its components. Another problem in reliability theory is one of estimating the parameters of the assumed failure models. The estimation may be based on data collected over censored or uncensored life tests. In many reliability problems, the failure data are simply quantitatively inadequate, especially in engineering design and maintenance system. The Bayesian analyses are more beneficial than the classical one in such cases. The Bayesian estimation analyses allow us to combine past knowledge or experience in the form of an apriori distribution with life test data to make inferences of the parameter of interest. In this paper, we have investigated the application of the Bayesian estimation analyses to competing risk systems. The cases are limited to the models with independent causes of failure by using the Weibull distribution as our model. A simulation is conducted for this distribution with the objectives of verifying the models and the estimators and investigating the performance of the estimators for varying sample size. The simulation data are analyzed by using Bayesian and the maximum likelihood analyses. The simulation results show that the change of the true of parameter relatively to another will change the value of standard deviation in an opposite direction. For a perfect information on the prior distribution, the estimation methods of the Bayesian analyses are better than those of the maximum likelihood. The sensitivity analyses show some amount of sensitivity over the shifts of the prior locations. They also show the robustness of the Bayesian analysis within the range

  15. A competing risks approach for time estimation of household WEEE disposal

    SciTech Connect

    Gutierrez, E.; Adenso-Diaz, B.; Lozano, S.; Gonzalez-Torre, P.

    2010-08-15

    The recent growth in the number of electrical and electronic devices is viewed as one the priority waste streams in European Union waste management policy. This paper presents the findings of a survey to study domestic habits with respect to Waste Electrical and Electronic Equipment (WEEE) in Spain. A specific problem when performing this estimation arises from the fact that consumers quite often store old appliances at home when they are no longer used. Focusing on four different types of appliance, survival analysis (SA) is used to study both the usage span and the reasons for no longer using each device. The time that the discarded products were kept at home before being disposed of was studied using competing risks (CR) analysis. The results of the analysis provide information on the distribution of the studied variables for the different outcomes as well as the influence exerted by the socio-demographic variables considered. Relations between these characteristics and the storage time of the appliances before disposal emerge based on survey data. For instance, the CR model finds that the storage time of the some appliances (i.e. refrigerator) is related to these social-demographics factors. However, other appliances (i.e. microwave oven) are less influenced by these factors. The attitude and motivation of the respondents to the survey as regards the End-of-Life of appliances were also analysed. A majority of respondents do not store discarded appliances at home. The first reason for storing appliances at home is the possibility of it being useful in the future and the second that the respondents did not know what to do with them.

  16. A competing risks approach for time estimation of household WEEE disposal.

    PubMed

    Gutiérrez, E; Adenso-Díaz, B; Lozano, S; González-Torre, P

    2010-01-01

    The recent growth in the number of electrical and electronic devices is viewed as one the priority waste streams in European Union waste management policy. This paper presents the findings of a survey to study domestic habits with respect to Waste Electrical and Electronic Equipment (WEEE) in Spain. A specific problem when performing this estimation arises from the fact that consumers quite often store old appliances at home when they are no longer used. Focusing on four different types of appliance, survival analysis (SA) is used to study both the usage span and the reasons for no longer using each device. The time that the discarded products were kept at home before being disposed of was studied using competing risks (CR) analysis. The results of the analysis provide information on the distribution of the studied variables for the different outcomes as well as the influence exerted by the socio-demographic variables considered. Relations between these characteristics and the storage time of the appliances before disposal emerge based on survey data. For instance, the CR model finds that the storage time of the some appliances (i.e. refrigerator) is related to these social-demographics factors. However, other appliances (i.e. microwave oven) are less influenced by these factors. The attitude and motivation of the respondents to the survey as regards the End-of-Life of appliances were also analysed. A majority of respondents do not store discarded appliances at home. The first reason for storing appliances at home is the possibility of it being useful in the future and the second that the respondents did not know what to do with them.

  17. Medical language proficiency: A discussion of interprofessional language competencies and potential for patient risk.

    PubMed

    Hull, Melodie

    2016-02-01

    In increasingly multilingual healthcare environments worldwide, ensuring accurate, effective communication is requisite. Language proficiency is essential, particularly medical language proficiency. Medical language is a universal construct in healthcare, the shared language of health and allied health professions. It is highly evolved, career-specific, technical and cultural-bound-a language for specific purposes. Its function differs significantly from that of a standard language. Proficiency requires at minimum, a common understanding of discipline-specific jargon, abstracts, euphemisms, abbreviations; acronyms. An optimal medical language situation demands a level of competency beyond the superficial wherein one can convey or interpret deeper meanings, distinguish themes, voice opinion, and follow directions precisely. It necessitates the use of clarity, and the ability to understand both lay and formal language-characteristics not essential to standard language. Proficiency influences professional discourse and can have the potential to positively or negatively affect patient outcomes. While risks have been identified when there is language discordance between care provider and patient, almost nothing has been said about this within care teams themselves. This article will do so in anticipation that care providers, regulators, employers, and researchers will acknowledge potential language-based communication barriers and work towards resolutions. This is predicated on the fact that the growing interest in language and communication in healthcare today appears to be rested in globalization and increasingly linguistically diverse patient populations. Consideration of the linguistically diverse healthcare workforce is absent. An argument will be posited that if potential risks to patient safety exist and there are potentials for disengagement from care by patients when health providers do not speak their languages then logically these language-based issues can

  18. Medical language proficiency: A discussion of interprofessional language competencies and potential for patient risk.

    PubMed

    Hull, Melodie

    2016-02-01

    In increasingly multilingual healthcare environments worldwide, ensuring accurate, effective communication is requisite. Language proficiency is essential, particularly medical language proficiency. Medical language is a universal construct in healthcare, the shared language of health and allied health professions. It is highly evolved, career-specific, technical and cultural-bound-a language for specific purposes. Its function differs significantly from that of a standard language. Proficiency requires at minimum, a common understanding of discipline-specific jargon, abstracts, euphemisms, abbreviations; acronyms. An optimal medical language situation demands a level of competency beyond the superficial wherein one can convey or interpret deeper meanings, distinguish themes, voice opinion, and follow directions precisely. It necessitates the use of clarity, and the ability to understand both lay and formal language-characteristics not essential to standard language. Proficiency influences professional discourse and can have the potential to positively or negatively affect patient outcomes. While risks have been identified when there is language discordance between care provider and patient, almost nothing has been said about this within care teams themselves. This article will do so in anticipation that care providers, regulators, employers, and researchers will acknowledge potential language-based communication barriers and work towards resolutions. This is predicated on the fact that the growing interest in language and communication in healthcare today appears to be rested in globalization and increasingly linguistically diverse patient populations. Consideration of the linguistically diverse healthcare workforce is absent. An argument will be posited that if potential risks to patient safety exist and there are potentials for disengagement from care by patients when health providers do not speak their languages then logically these language-based issues can

  19. Risk Management. Unit 20. Level 1. Instructor Guide. PACE: Program for Acquiring Competence in Entrepreneurship. Third Edition. Research & Development Series No. 301-20.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This instructor guide for a unit on risk management in the PACE (Program for Acquiring Competence in Entrepreneurship) curriculum includes the full text of the student module and lesson plans, instructional suggestions, and other teacher resources. The competencies that are incorporated into this module are at Level 1 of learning--understanding…

  20. Risk.

    PubMed

    Cole, Stephen R; Hudgens, Michael G; Brookhart, M Alan; Westreich, Daniel

    2015-02-15

    The epidemiologist primarily studies transitions between states of health and disease. The purpose of the present article is to define a foundational parameter for such studies, namely risk. We begin simply and build to the setting in which there is more than 1 event type (i.e., competing risks or competing events), as well as more than 1 treatment or exposure level of interest. In the presence of competing events, the risks are a set of counterfactual cumulative incidence functions for each treatment. These risks can be depicted visually and summarized numerically. We use an example from the study of human immunodeficiency virus to illustrate concepts. PMID:25660080

  1. Twitter as a Potential Disaster Risk Reduction Tool. Part IV: Competency-based Education and Training Guidelines to Promote Community Resiliency.

    PubMed

    Yeager, Violet; Cooper, Guy Paul; Burkle, Frederick M; Subbarao, Italo

    2015-06-29

    Twitter can be an effective tool for disaster risk reduction but gaps in education and training exist in current public health and disaster management educational competency standards.  Eleven core public health and disaster management competencies are proposed that incorporate Twitter as a tool for effective disaster risk reduction.  Greater funding is required to promote the education and training of this tool for those in professional schools and in the current public health and disaster management workforce.

  2. An in silico parametric model of vertebrae trabecular bone based on density and microstructural parameters to assess risk of fracture in osteoporosis.

    PubMed

    Amjadi Kashani, Mohammad Reza; Nikkhoo, Mohammad; Khalaf, Kinda; Firoozbakhsh, Keikhosrow; Arjmand, Navid; Razmjoo, Arash; Parnianpour, Mohamad

    2014-12-01

    Osteoporosis is a progressive bone disease characterized by deterioration in the quantity and quality of bone, leading to inferior mechanical properties and an increased risk of fracture. Current assessment of osteoporosis is typically based on bone densitometry tools such as Quantitative Computed Tomography (QCT) and Dual Energy X-ray absorptiometry (DEXA). These assessment modalities mainly rely on estimating the bone mineral density (BMD). Hence present densitometry tools describe only the deterioration of the quantity of bone associated with the disease and not the affected morphology or microstructural changes, resulting in potential incomplete assessment, many undetected patients, and unexplained fractures. In this study, an in-silico parametric model of vertebral trabecular bone incorporating both material and microstructural parameters was developed towards the accurate assessment of osteoporosis and the consequent risk of bone fracture. The model confirms that the mechanical properties such as strength and stiffness of vertebral trabecular tissue are highly influenced by material properties as well as morphology characteristics such as connectivity, which reflects the quality of connected inter-trabecular parts. The FE cellular solid model presented here provides a holistic approach that incorporates both material and microstructural elements associated with the degenerative process, and hence has the potential to provide clinical practitioners and researchers with more accurate assessment method for the degenerative changes leading to inferior mechanical properties and increased fracture risk associated with age and/or disease such as Osteoporosis. PMID:25515229

  3. Risk communication as a core public health competence in infectious disease management: Development of the ECDC training curriculum and programme.

    PubMed

    Dickmann, Petra; Abraham, Thomas; Sarkar, Satyajit; Wysocki, Piotr; Cecconi, Sabrina; Apfel, Franklin; Nurm, Ülla-Karin

    2016-01-01

    Risk communication has been identified as a core competence for guiding public health responses to infectious disease threats. The International Health Regulations (2005) call for all countries to build capacity and a comprehensive understanding of health risks before a public health emergency to allow systematic and coherent communication, response and management. Research studies indicate that while outbreak and crisis communication concepts and tools have long been on the agenda of public health officials, there is still a need to clarify and integrate risk communication concepts into more standardised practices and improve risk communication and health, particularly among disadvantaged populations. To address these challenges, the European Centre for Disease Prevention and Control (ECDC) convened a group of risk communication experts to review and integrate existing approaches and emerging concepts in the development of a training curriculum. This curriculum articulates a new approach in risk communication moving beyond information conveyance to knowledge- and relationship-building. In a pilot training this approach was reflected both in the topics addressed and in the methods applied. This article introduces the new conceptual approach to risk communication capacity building that emerged from this process, presents the pilot training approach developed, and shares the results of the course evaluation.

  4. Risk communication as a core public health competence in infectious disease management: Development of the ECDC training curriculum and programme.

    PubMed

    Dickmann, Petra; Abraham, Thomas; Sarkar, Satyajit; Wysocki, Piotr; Cecconi, Sabrina; Apfel, Franklin; Nurm, Ülla-Karin

    2016-01-01

    Risk communication has been identified as a core competence for guiding public health responses to infectious disease threats. The International Health Regulations (2005) call for all countries to build capacity and a comprehensive understanding of health risks before a public health emergency to allow systematic and coherent communication, response and management. Research studies indicate that while outbreak and crisis communication concepts and tools have long been on the agenda of public health officials, there is still a need to clarify and integrate risk communication concepts into more standardised practices and improve risk communication and health, particularly among disadvantaged populations. To address these challenges, the European Centre for Disease Prevention and Control (ECDC) convened a group of risk communication experts to review and integrate existing approaches and emerging concepts in the development of a training curriculum. This curriculum articulates a new approach in risk communication moving beyond information conveyance to knowledge- and relationship-building. In a pilot training this approach was reflected both in the topics addressed and in the methods applied. This article introduces the new conceptual approach to risk communication capacity building that emerged from this process, presents the pilot training approach developed, and shares the results of the course evaluation. PMID:27103616

  5. Risk and Protective Factors for Children of Adolescents: Maternal Depression and Parental Sense of Competence

    ERIC Educational Resources Information Center

    Knoche, Lisa L.; Givens, Jami E.; Sheridan, Susan M.

    2007-01-01

    We investigated the relationship between depression and parental sense of competence to child cognitive outcomes for a sample of 49 adolescent mothers and their young children ("Mean age" = 9 1/2 months) enrolled in a student parenting program. Cognitive development of the infants and toddlers was assessed using the Bayley Scales of Infant…

  6. Core Competency Modification. A Manual for Working with At-Risk/Special Needs Students.

    ERIC Educational Resources Information Center

    Loess Hills Area Education Agency 13, Council Bluffs, IA.

    This manual assists teachers in providing adaptations for disabled and disadvantaged students to ensure their success in the regular vocational classroom and to meet requirements of the new vocational education standards in Iowa, which call for a competency-based curriculum. Introductory pages include strategies for teaching special needs…

  7. Instructional Climates in Preschool Children Who Are At-Risk. Part II: Perceived Physical Competence

    ERIC Educational Resources Information Center

    Robinson, Leah E.; Rudisill, Mary E.; Goodway, Jacqueline D.

    2009-01-01

    In Part II of this study, we examined the effect of two 9-week instructional climates (low-autonomy [LA] and mastery motivational climate [MMC]) on perceived physical competence (PPC) in preschoolers (N = 117). Participants were randomly assigned to an LA, MMC, or comparison group. PPC was assessed by a pretest, posttest, and retention test with…

  8. A Competence-Based Science Learning Framework Illustrated Through the Study of Natural Hazards and Disaster Risk Reduction

    NASA Astrophysics Data System (ADS)

    Oyao, Sheila G.; Holbrook, Jack; Rannikmäe, Miia; Pagunsan, Marmon M.

    2015-09-01

    This article proposes a competence-based learning framework for science teaching, applied to the study of 'big ideas', in this case to the study of natural hazards and disaster risk reduction (NH&DRR). The framework focuses on new visions of competence, placing emphasis on nurturing connectedness and behavioral actions toward resilience and sustainability. The framework draws together competences familiarly expressed as cognitive knowledge and skills, plus dispositions and adds connectedness and action-related behaviors, and applies this by means of a progression shift associated with NH&DRR from abilities to capabilities. The target is enhanced scientific literacy approached through an education through science focus, amplified through the study of a big idea, promotion of sustained resilience in the face of disaster and the taking of responsibilities for behavioral actions. The framework is applied to a learning progression for each interrelated education dimension, thus serving as a guide for both the development of abilities and as a platform for stimulating student capabilities within instruction and assessment.

  9. Conceptualizing and Re-Evaluating Resilience across Levels of Risk, Time, and Domains of Competence

    ERIC Educational Resources Information Center

    Vanderbilt-Adriance, Ella; Shaw, Daniel S.

    2008-01-01

    This article examines potential theoretical constraints on resilience across levels of risk, time, and domain of outcome. Studies of resilience are reviewed as they relate to the prevalence of resilience across levels of risk (e.g., single life events vs. cumulative risk), time, and domains of adjustment. Based on a thorough review of pertinent…

  10. Addressing missing covariates for the regression analysis of competing risks: Prognostic modelling for triaging patients diagnosed with prostate cancer.

    PubMed

    Escarela, Gabriel; Ruiz-de-Chavez, Juan; Castillo-Morales, Alberto

    2016-08-01

    Competing risks arise in medical research when subjects are exposed to various types or causes of death. Data from large cohort studies usually exhibit subsets of regressors that are missing for some study subjects. Furthermore, such studies often give rise to censored data. In this article, a carefully formulated likelihood-based technique for the regression analysis of right-censored competing risks data when two of the covariates are discrete and partially missing is developed. The approach envisaged here comprises two models: one describes the covariate effects on both long-term incidence and conditional latencies for each cause of death, whilst the other deals with the observation process by which the covariates are missing. The former is formulated with a well-established mixture model and the latter is characterised by copula-based bivariate probability functions for both the missing covariates and the missing data mechanism. The resulting formulation lends itself to the empirical assessment of non-ignorability by performing sensitivity analyses using models with and without a non-ignorable component. The methods are illustrated on a 20-year follow-up involving a prostate cancer cohort from the National Cancer Institutes Surveillance, Epidemiology, and End Results program.

  11. Prediction of skull fracture risk for children 0-9 months old through validated parametric finite element model and cadaver test reconstruction.

    PubMed

    Li, Zhigang; Liu, Weiguo; Zhang, Jinhuan; Hu, Jingwen

    2015-09-01

    Skull fracture is one of the most common pediatric traumas. However, injury assessment tools for predicting pediatric skull fracture risk is not well established mainly due to the lack of cadaver tests. Weber conducted 50 pediatric cadaver drop tests for forensic research on child abuse in the mid-1980s (Experimental studies of skull fractures in infants, Z Rechtsmed. 92: 87-94, 1984; Biomechanical fragility of the infant skull, Z Rechtsmed. 94: 93-101, 1985). To our knowledge, these studies contained the largest sample size among pediatric cadaver tests in the literature. However, the lack of injury measurements limited their direct application in investigating pediatric skull fracture risks. In this study, 50 pediatric cadaver tests from Weber's studies were reconstructed using a parametric pediatric head finite element (FE) model which were morphed into subjects with ages, head sizes/shapes, and skull thickness values that reported in the tests. The skull fracture risk curves for infants from 0 to 9 months old were developed based on the model-predicted head injury measures through logistic regression analysis. It was found that the model-predicted stress responses in the skull (maximal von Mises stress, maximal shear stress, and maximal first principal stress) were better predictors than global kinematic-based injury measures (peak head acceleration and head injury criterion (HIC)) in predicting pediatric skull fracture. This study demonstrated the feasibility of using age- and size/shape-appropriate head FE models to predict pediatric head injuries. Such models can account for the morphological variations among the subjects, which cannot be considered by a single FE human model.

  12. Conceptualizing and Re-Evaluating Resilience Across Levels of Risk, Time, and Domains of Competence

    PubMed Central

    Shaw, Daniel S.

    2009-01-01

    This article examines potential theoretical constraints on resilience across levels of risk, time, and domain of outcome. Studies of resilience are reviewed as they relate to the prevalence of resilience across levels of risk (e.g., single life events vs. cumulative risk), time, and domains of adjustment. Based on a thorough review of pertinent literature, we conclude that resilience, as a global construct, appears to be rare at the highest levels of risk, and that resilience may benefit from a narrower conceptualization focusing on specific outcomes at specific timepoints in development. The implication of this conclusion for future research and intervention efforts is then discussed. PMID:18379875

  13. The Relation Between Adolescent Social Competence and Young Adult Delinquency and Educational Attainment Among At-Risk Youth: The Mediating Role of Peer Delinquency

    PubMed Central

    Stepp, Stephanie D; Pardini, Dustin A; Loeber, Rolf; Morris, Nancy A

    2015-01-01

    Objective We examined trajectories of adolescent social competence as a resilience factor among at-risk youth. To examine potential mechanisms of this resilience process, we investigated the putative mediating effect of peer delinquency on the relation between adolescent social competence and young adult delinquency seriousness and educational attainment. Method Participants (n = 257) were screened to be at risk for antisocial behaviour at age 13 years. Data were derived from an ongoing longitudinal study of the development of antisocial and delinquent behaviour among inner-city boys, the Pittsburgh Youth Study. We used data collected from participants when aged 13 years until they were aged 25.5 years for our study. Results Results indicated that boys with high levels of social competence decreased their involvement with deviant peers throughout adolescence, which, in turn, predicted less serious forms of delinquency in early adulthood. Social competence had a direct effect on educational attainment in early adulthood, as boys who developed social competencies in adolescence went further in school irrespective of their involvement with delinquent peers. Conclusions Results suggest that promoting the development of social competencies and reducing involvement with delinquent peers will protect at-risk youth from engaging in serious delinquency in early adulthood while increasing their educational success. PMID:21878156

  14. Chronic Graft Loss and Death in Patients With Post-Transplant Malignancy in Living Kidney Transplantation: A Competing Risk Analysis

    PubMed Central

    Salesi, Mahmoud; Rostami, Zohreh; Rahimi Foroushani, Abbas; Mehrazmay, Ali Reza; Mohammadi, Jamile; Einollahi, Behzad; Asgharian, Saeed; Eshraghian, Mohammad Reza

    2014-01-01

    Background: Malignancy is a common complication after renal transplantation. Death with functioning graft and chronic graft loss are two competing outcomes in patients with post-transplant malignancies. Objectives: The purpose of our study was to evaluate the risk factors associated with cumulative incidence of these two outcomes. Patients and Methods: Fine-Gray model was used for 266 cases with post-transplant malignancy in Iran. These patients were followed-up from the diagnosis until the date of last visit, chronic graft loss, or death, subsequently. Results: At the end of the study, as competing events, chronic graft loss and death with functioning graft were seen in 27 (10.2%) and 53 cases (19.9%), respectively, while 186 cases (69.9%) were accounted as censored. The incidence rate of death was approximately two-time of the incidence rate of chronic graft loss (8.6 vs. 4.4 per 100 person-years). In multivariate analysis, significant risk factors associated with cumulative incidence of death included age (P < 0.007, subhazard ratio (SHR) = 1.03), type of cancer (P < 0.0001), and response to treatment (P < 0.0001, SHR = 0.027). The significant risk factors associated with cumulative incidence of chronic graft loss were gender (P = 0.05, SHR = 0.37), treatment modality (P < 0.0001), and response to treatment (P = 0.048, SHR = 0.47). Conclusions: Using these factors, nephrologists may predict the occurrence of graft loss or death. If the probability of graft loss was higher, physicians can decrease the immunosuppressive medications dosage to decrease the incidence of graft loss. PMID:25032129

  15. Twitter as a Potential Disaster Risk Reduction Tool. Part IV: Competency-based Education and Training Guidelines to Promote Community Resiliency

    PubMed Central

    Yeager, Violet; Cooper, Guy Paul; Burkle, Frederick M.; Subbarao, Italo

    2015-01-01

    Twitter can be an effective tool for disaster risk reduction but gaps in education and training exist in current public health and disaster management educational competency standards.  Eleven core public health and disaster management competencies are proposed that incorporate Twitter as a tool for effective disaster risk reduction.  Greater funding is required to promote the education and training of this tool for those in professional schools and in the current public health and disaster management workforce.  PMID:26203398

  16. Eating competence of elderly Spanish adults is associated with a healthy diet and a favorable cardiovascular disease risk profile.

    PubMed

    Lohse, Barbara; Psota, Tricia; Estruch, Ramón; Zazpe, Itziar; Sorli, José V; Salas-Salvadó, Jordi; Serra, Mercè; Krall, Jodi Stotts; Márquez, Fabiola; Ros, Emilio

    2010-07-01

    Eating competence (EC), a bio-psychosocial model for intrapersonal approaches to eating and food-related behaviors, is associated with less weight dissatisfaction, lower BMI, and increased HDL-cholesterol in small U.S. studies, but its relationship to nutrient quality and overall cardiovascular risk have not been examined. Prevención con Dieta Mediterránea (PREDIMED) is a 5-y controlled clinical trial evaluating Mediterranean diet efficacy on the primary prevention of cardiovascular diseases (CVD) in Spain. In a cross-sectional study, 638 PREDIMED participants (62% women, mean age 67 y) well phenotyped for cardiovascular risk factors were assessed for food intake and EC using validated questionnaires. Overall, 45.6% were eating-competent. EC was associated with being male and energy intake (P < 0.01). After gender and energy adjustment, participants with EC compared with those without showed higher fruit intake and greater adherence to the Mediterranean diet (P < 0.05) and tended to consume more fish (P = 0.076) and fewer dairy products (P = 0.054). EC participants tended to have a lower BMI (P = 0.057) and had a lower fasting blood glucose concentration and serum LDL-:HDL-cholesterol ratio (P < 0.05) and a higher HDL-cholesterol concentration (P = 0.025) after gender adjustment. EC participants had lower odds ratios (OR) of having a blood glucose concentration >5.6 mmol/L (0.71; 95% CI 0.51-0.98) and HDL-cholesterol <1.0 mmol/L (0.70; 95% CI 0.68-1.00). The OR of actively smoking, being obese, or having a serum LDL-cholesterol concentration > or =3.4 mmol/L were <1.0, but the 95% CI included the 1.0 (P > 0.1). Our findings support further examination of EC as a strategy for enhancing diet quality and CVD prevention. PMID:20505016

  17. Advantage of the modified Lunn-McNeil technique over Kalbfleisch-Prentice technique in competing risks

    NASA Astrophysics Data System (ADS)

    Lukman, Iing; Ibrahim, Noor A.; Daud, Isa B.; Maarof, Fauziah; Hassan, Mohd N.

    2002-03-01

    Survival analysis algorithm is often applied in the data mining process. Cox regression is one of the survival analysis tools that has been used in many areas, and it can be used to analyze the failure times of aircraft crashed. Another survival analysis tool is the competing risks where we have more than one cause of failure acting simultaneously. Lunn-McNeil analyzed the competing risks in the survival model using Cox regression with censored data. The modified Lunn-McNeil technique is a simplify of the Lunn-McNeil technique. The Kalbfleisch-Prentice technique is involving fitting models separately from each type of failure, treating other failure types as censored. To compare the two techniques, (the modified Lunn-McNeil and Kalbfleisch-Prentice) a simulation study was performed. Samples with various sizes and censoring percentages were generated and fitted using both techniques. The study was conducted by comparing the inference of models, using Root Mean Square Error (RMSE), the power tests, and the Schoenfeld residual analysis. The power tests in this study were likelihood ratio test, Rao-score test, and Wald statistics. The Schoenfeld residual analysis was conducted to check the proportionality of the model through its covariates. The estimated parameters were computed for the cause-specific hazard situation. Results showed that the modified Lunn-McNeil technique was better than the Kalbfleisch-Prentice technique based on the RMSE measurement and Schoenfeld residual analysis. However, the Kalbfleisch-Prentice technique was better than the modified Lunn-McNeil technique based on power tests measurement.

  18. Reducing psychosocial risks through supervisors' development: a contribution for a brief version of the "Stress Management Competency Indicator Tool".

    PubMed

    Toderi, Stefano; Gaggia, Andrea; Balducci, Cristian; Sarchielli, Guido

    2015-06-15

    With the recent changes in the world of work psychosocial risks are increasingly prevalent, causing work stress and physical and mental illnesses, which have a tremendous impact on public health and social participation. Supervisors' behaviour development was proposed as an innovative intervention that can reduce psychosocial risks. The "Stress Management Competency Indicator Tool" is one of the most important questionnaires that assess managers' preventive behaviour. However, its psychometric properties have never been evaluated and the length of the questionnaire (66 items) limits its practical applicability. The aim of this study was to contribute to the development of the questionnaire by providing psychometric evidence on a brief version of the tool focusing on the "Managing and Communicating existing and future Work" cluster of behaviours, which has been found to be the crucial one in terms of stress prevention. A questionnaire was administered to 178 employees of two Italian public organizations (a municipality and a hospital), measuring the supervisors' "Managing and Communicating existing and future Work" competency, and the affective well-being and work team effectiveness. The results showed excellent psychometric properties of the supervisors' behaviour scale and confirmed the expected relationships with criterion outcomes (affective well-being and team effectiveness). Overall, the factorial structure and dimensionality, the construct validity and reliability, and the concurrent validity of the tool were strongly supported by this study. We concluded that the brief version of the scale is a valid and reliable measure that can be easily used in practice and that can contribute to the development of research and practice on this topic. PMID:25770947

  19. Parametric Cost Deployment

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.

    1995-01-01

    Parametric cost analysis is a mathematical approach to estimating cost. Parametric cost analysis uses non-cost parameters, such as quality characteristics, to estimate the cost to bring forth, sustain, and retire a product. This paper reviews parametric cost analysis and shows how it can be used within the cost deployment process.

  20. Resilience and Risk Competence in Schools: Theory/Knowledge and International Application in Project REBOUND

    ERIC Educational Resources Information Center

    Brown, Joel H.; Jean-Marie, Gaetane; Beck, Jerome

    2010-01-01

    Despite a 50-year interdisciplinary and longitudinal research legacy--showing that nearly 80% of young people considered most "at risk" thrive by midlife--only recently have practitioners/researchers engaged in the explicit, prospective facilitation of "resilience" in educational settings. Here, theory/knowledge distinguishing and extending risk…

  1. A Multivariate Investigation of Maternal Risks and Their Relationship to Low-Income, Preschool Children's Competencies

    ERIC Educational Resources Information Center

    Perry, Marlo A.; Fantuzzo, John W.

    2010-01-01

    Utilizing a developmental-ecological framework, the purpose of this study was to understand the unique impact of multiple maternal risks across time on ethnically diverse, low-income, preschool children's cognitive skills, pro-social behaviors, and behavior problems. Additionally, this study sought to understand the variability of maternal risks…

  2. Parental Beliefs and Values Related to Family Risk, Educational Intervention, and Child Academic Competence.

    ERIC Educational Resources Information Center

    Campbell, Frances A.; And Others

    1991-01-01

    Studied the relation of child-rearing beliefs and values of parents of children entering kindergarten to children's academic achievements. Examined effects of a child-centered educational preschool program for socioeconomically disadvantaged children on parents' beliefs and values. Parents of children at risk differed from other parents in beliefs…

  3. Sparse representation of multi parametric DCE-MRI features using K-SVD for classifying gene expression based breast cancer recurrence risk

    NASA Astrophysics Data System (ADS)

    Mahrooghy, Majid; Ashraf, Ahmed B.; Daye, Dania; Mies, Carolyn; Rosen, Mark; Feldman, Michael; Kontos, Despina

    2014-03-01

    We evaluate the prognostic value of sparse representation-based features by applying the K-SVD algorithm on multiparametric kinetic, textural, and morphologic features in breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). K-SVD is an iterative dimensionality reduction method that optimally reduces the initial feature space by updating the dictionary columns jointly with the sparse representation coefficients. Therefore, by using K-SVD, we not only provide sparse representation of the features and condense the information in a few coefficients but also we reduce the dimensionality. The extracted K-SVD features are evaluated by a machine learning algorithm including a logistic regression classifier for the task of classifying high versus low breast cancer recurrence risk as determined by a validated gene expression assay. The features are evaluated using ROC curve analysis and leave one-out cross validation for different sparse representation and dimensionality reduction numbers. Optimal sparse representation is obtained when the number of dictionary elements is 4 (K=4) and maximum non-zero coefficients is 2 (L=2). We compare K-SVD with ANOVA based feature selection for the same prognostic features. The ROC results show that the AUC of the K-SVD based (K=4, L=2), the ANOVA based, and the original features (i.e., no dimensionality reduction) are 0.78, 0.71. and 0.68, respectively. From the results, it can be inferred that by using sparse representation of the originally extracted multi-parametric, high-dimensional data, we can condense the information on a few coefficients with the highest predictive value. In addition, the dimensionality reduction introduced by K-SVD can prevent models from over-fitting.

  4. Competence, Self-Esteem, and Coping Efficacy as Mediators of Ecological Risk and Depressive Symptoms in Urban African American and European American Youth

    ERIC Educational Resources Information Center

    Prelow, Hazel M.; Weaver, Scott R.; Swenson, Rebecca R.

    2006-01-01

    Structural equation modeling was used to test [Sandler, "American Journal of Community Psychology" 29: 19-61.] a theoretical model of risk and resilience in an urban sample of African American and European American adolescents. The aims of the present study were to examine whether self-system processes (i.e., competence, self-esteem, and coping…

  5. Competing-Risks Mortality After Radiotherapy vs. Observation for Localized Prostate Cancer: A Population-based Study

    SciTech Connect

    Abdollah, Firas; Sun, Maxine; Schmitges, Jan; Thuret, Rodolphe; Tian, Zhe; Shariat, Shahrokh F.; Briganti, Alberto; Jeldres, Claudio; Perrotte, Paul; Montorsi, Francesco; Karakiewicz, Pierre I.

    2012-09-01

    Purpose: Contemporary patients with localized prostate cancer (PCa) are more frequently treated with radiotherapy. However, there are limited data on the effect of this treatment on cancer-specific mortality (CSM). Our objective was to test the relationship between radiotherapy and survival in men with localized PCa and compare it with those treated with observation. Methods: A population-based cohort identified 68,797 men with cT1-T2 PCa treated with radiotherapy or observation between the years 1992 and 2005. Propensity-score matching was used to minimize potential bias related to treatment assignment. Competing-risks analyses tested the effect of treatment type (radiotherapy vs. observation) on CSM, after accounting to other-cause mortality. All analyses were carried out within PCa risk, baseline comorbidity status, and age groups. Results: Radiotherapy was associated with more favorable 10-year CSM rates than observation in patients with high-risk PCa (8.8 vs. 14.4%, hazard ratio [HR]: 0.59, 95% confidence interval [CI]: 0.50-0.68). Conversely, the beneficial effect of radiotherapy on CSM was not evident in patients with low-intermediate risk PCa (3.7 vs. 4.1%, HR: 0.91, 95% CI: 0.80-1.04). Radiotherapy was beneficial in elderly patients (5.6 vs. 7.3%, HR: 0.70, 95% CI: 0.59-0.80). Moreover, it was associated with improved CSM rates among patients with no comorbidities (5.7 vs. 6.5%, HR: 0.81, 95% CI: 0.67-0.98), one comorbidity (4.6 vs. 6.0%, HR: 0.87, 95% CI: 0.75-0.99), and more than two comorbidities (4.2 vs. 5.0%, HR: 0.79, 95% CI: 0.65-0.96). Conclusions: Radiotherapy substantially improves CSM in patients with high-risk PCa, with little or no benefit in patients with low-/intermediate-risk PCa relative to observation. These findings must be interpreted within the context of the limitations of observational data.

  6. Risk management for the emergency physician: competency and decision-making capacity, informed consent, and refusal of care against medical advice.

    PubMed

    Magauran, Brendan G

    2009-11-01

    This article focuses on those times that the emergency physician (EP) and patient do not agree on a treatment option. Attention is placed on the risk management issues relevant to the patient's unexpected choice. Emphasis is placed on determining a patient's competency or capability of making clinical decisions, with particular focus on the EP deciding that patient competency requires a formal evaluation. The EP should have a strategy for assessing clinical decision-making capability and an understanding of what circumstances should act as a trigger for considering such an assessment. Attention to documentation issues around informed consent, common barriers to consent, refusal of care, and ED discharge against medical advice are examined.

  7. Proximal femoral replacement in the management of acute periprosthetic fractures of the hip: a competing risks survival analysis

    PubMed Central

    Colman, Matthew; Choi, Lisa; Chen, Antonia; Crossett, Lawrence; Tarkin, Ivan; McGough, Richard

    2014-01-01

    To examine the mortality and implant survivorship of proximal femoral replacement (PFR), revision total hip arthroplasty (REV) and open reduction internal fixation (ORIF) in the treatment of acute periprosthetic fractures of the proximal femur, we retrospectively reviewed 97 consecutive acute periprosthetic proximal femoral fractures from 2000–2010. Three groups were defined: PFR (n=21), REV (n=19), and ORIF (n=57). Outcome measures were all-cause mortality, implant failure, and reoperation. Competing Risks survival analysis of overall mortality during the mean 35-month follow-up showed no statistical difference between the three groups (p=0.65; 12 and 60 month mortality for PFR: 37%, 45%; REV: 16%, 46%; ORIF: 14%, 100%). Implant survival was worse for the PFR group (p=0.03, 12 and 60-month implant failure rate for PFR: 5%, 39%; REV: 7%, 7%; ORIF 2%, 2%). We conclude that PFR as compared with REV or ORIF may have worse medium-term implant survival, primarily due to instability and dislocation. PMID:23856062

  8. Negotiating competency, professionalism and risk: the integration of complementary and alternative medicine by nurses and midwives in NHS hospitals.

    PubMed

    Cant, Sarah; Watts, Peter; Ruston, Annmarie

    2011-02-01

    This qualitative interview study examined the use of complementary and alternative medicine (CAM) by nurses and midwives in NHS hospital settings in 2008 in the UK. It showed that the groundswell of interest in CAM in the 1990s had diminished by this time due to changes to policy and funding, and increasingly stringent clinical governance. Nevertheless, CAM provided an opportunity for committed and self-motivated practitioners to extend their therapeutic repertoire and develop affective dimensions of practice. However, the integration of CAM did not afford the autonomy, status and material gains traditionally associated with a collective professional project. In practice, occupational strategies were individualistic, and grounded in the assertion of competency through expressions of professionalism rather than the credentialism which underpins classic professionalisation. Central to these strategies was CAM related risk, which became a means by which to claim occupational space. However, the extent to which the adoption of CAM enhanced the nurses' and midwives' roles was limited by traditional medical authority; the uncertain status of CAM knowledge; and the absence of collective strategies - which together often left practitioners in a position of vulnerability.

  9. Quantifying intrinsic and extrinsic control of single-cell fates in cancer and stem/progenitor cell pedigrees with competing risks analysis

    PubMed Central

    Cornwell, J. A.; Hallett, R. M.; der Mauer, S. Auf; Motazedian, A.; Schroeder, T.; Draper, J. S.; Harvey, R. P.; Nordon, R. E.

    2016-01-01

    The molecular control of cell fate and behaviour is a central theme in biology. Inherent heterogeneity within cell populations requires that control of cell fate is studied at the single-cell level. Time-lapse imaging and single-cell tracking are powerful technologies for acquiring cell lifetime data, allowing quantification of how cell-intrinsic and extrinsic factors control single-cell fates over time. However, cell lifetime data contain complex features. Competing cell fates, censoring, and the possible inter-dependence of competing fates, currently present challenges to modelling cell lifetime data. Thus far such features are largely ignored, resulting in loss of data and introducing a source of bias. Here we show that competing risks and concordance statistics, previously applied to clinical data and the study of genetic influences on life events in twins, respectively, can be used to quantify intrinsic and extrinsic control of single-cell fates. Using these statistics we demonstrate that 1) breast cancer cell fate after chemotherapy is dependent on p53 genotype; 2) granulocyte macrophage progenitors and their differentiated progeny have concordant fates; and 3) cytokines promote self-renewal of cardiac mesenchymal stem cells by symmetric divisions. Therefore, competing risks and concordance statistics provide a robust and unbiased approach for evaluating hypotheses at the single-cell level. PMID:27250534

  10. AAOHN Competencies.

    PubMed

    2015-11-01

    The AAOHN Competency document is one of the core documents that define occupational health nursing practice. This article provides a description of the process used to update the competencies, as well as a description of the new competencies. PMID:26419544

  11. Cluster B personality symptoms in persons at genetic risk for schizophrenia are associated with social competence and activation of the right temporo-parietal junction during emotion processing.

    PubMed

    Goldschmidt, Micaela Giuliana; Villarreal, Mirta Fabiana; de Achával, Delfina; Drucaroff, Lucas Javier; Costanzo, Elsa Yolanda; Castro, Mariana Nair; Pahissa, Jaime; Camprodon, Joan; Nemeroff, Charles; Guinjoan, Salvador Martín

    2014-01-30

    Personality disorders are common in nonpsychotic siblings of patients with schizophrenia, and some personality traits in this group may be associated with an increased risk for full-blown psychosis. We sought to establish if faulty right-hemisphere activation induced by social cognitive tasks, as previously described in patients with schizophrenia, is associated with specific personality symptoms in their unaffected siblings. We observed that cluster B personality symptoms in this group were inversely related to activation in the right temporo parietal junction (rTPJ, a structure critical in social cognitive processing) in response to a basic emotion processing task and also to social competence, whereas in contrast to our initial hypothesis, cluster A traits were not associated with right hemisphere activation during emotion processing or with social competence. These findings suggest the existence of clinical traits in at-risk individuals which share a common neurobiological substrate with schizophrenia, in regards to social performance.

  12. First incident hospitalisation for Australian women aged 70 and beyond: A 10 year examination using competing risks.

    PubMed

    Harris, Melissa L; Dolja-Gore, Xenia; Kendig, Hal; Byles, Julie E

    2016-01-01

    There are increasing concerns regarding high hospital use among older adults and the capacity to manage the economic impact of the ageing population trend on healthcare systems. First hospitalisation in old age may act as a catalyst for ongoing intensification of health problems and acute care use. This study examined factors associated with first incident hospitalisation in women aged over 70, accounting for the health inequalities associated with geographic location. Survey data from 3780 women from the 1921 to 1926 cohort of the Australian Longitudinal Study on Women's Health were matched with the Admitted Patients Data Collection and National Death Index. Days to first event (hospitalisation or death) were modelled using competing risks methods. A total of 3065 (80.3%) women had at least one hospital admission. More than half of the top 15 reasons for first hospitalisation were related to cardiovascular disease, with atrial fibrillation the most common. Proportional subdistribution hazards models showed that first hospital admission was driven by enabling and need factors including asthma/bronchitis diagnosis (HR=1.16; p=0.047), private health insurance (HR=1.16; p=0.004) more than two prescribed medications in previous month (HR=1.31; p=0.001), more than four general practitioner visits in previous year (HR=1.50; p=0.034), lower physical functioning (HR=0.99; p<0.001) and living in an inner regional area (HR=1.17; p=0.003). First overnight hospitalisation was primarily related with potentially preventable and treatable chronic diseases. Primary and secondary strategies aimed at chronic disease generally, and better chronic disease management particularly for cardiovascular and respiratory diseases, may play a vital role in disease prevention or delay in readmissions among this population.

  13. Families, Risk, and Competence.

    ERIC Educational Resources Information Center

    Lewis, Michael, Ed.; Feiring, Candice, Ed.

    The problems of studying families arise from the difficulty in studying systems in which there are multiple elements interacting with each other and with the child. This book attests to the growing sophistication of the conceptualization and measurement techniques for understanding family processes. Chapters in the first part of the book, "The…

  14. Low Academic Competence in First Grade as a Risk Factor for Depressive Cognitions and Symptoms in Middle School

    PubMed Central

    Herman, Keith C.; Lambert, Sharon F.; Reinke, Wendy M.; Ialongo, Nicholas S.

    2013-01-01

    The present study investigated the role of low academic competence in the emergence of depressive cognitions and symptoms. Structural equation modeling was conducted on a longitudinal sample of African American boys (n = 253) and girls (n = 221). Results supported the hypothesized path models from academic competence in 1st grade to depressive symptoms in 7th grade, controlling for a host of correlated constructs (conduct problems, inattention, social problems). Perceived control in 6th grade mediated the effect of academic competence on depressive symptoms. Although the models fit the data well for both boys and girls, the path coefficients were notably larger for girls; in particular, multiple-group analysis revealed a statistically stronger effect of low academic competence on perceptions of control for girls. The study and findings fit well with counseling psychologists’ commitment to prevention activities and to culture-specific research. Implications for designing interventions and prevention strategies for children with early academic problems are discussed. PMID:26279587

  15. On the Importance of Accounting for Competing Risks in Pediatric Cancer Trials Designed to Delay or Avoid Radiotherapy: I. Basic Concepts and First Analyses

    SciTech Connect

    Tai, Bee-Choo; Grundy, Richard G.; Machin, David

    2010-04-15

    Purpose: In trials designed to delay or avoid irradiation among children with malignant brain tumor, although irradiation after disease progression is an important event, patients who have disease progression may decline radiotherapy (RT), or those without disease progression may opt for elective RT. To accurately describe the cumulative need for RT in such instances, it is crucial to account for these distinct events and to evaluate how each contributes to the delay or advancement of irradiation via a competing risks analysis. Methods and Materials: We describe the summary of competing events in such trials using competing risks methods based on cumulative incidence functions and Gray's test. The results obtained are contrasted with standard survival methods based on Kaplan-Meier curves, cause-specific hazard functions and log-rank test. Results: The Kaplan-Meier method overestimates all event-specific rates. The cause-specific hazard analysis showed reduction in hazards for all events (A: RT after progression; B: no RT after progression; C: elective RT) among children with ependymoma. For event A, a higher cumulative incidence was reported for ependymoma. Although Gray's test failed to detect any difference (p = 0.331) between histologic subtypes, the log-rank test suggested marginal evidence (p = 0.057). Similarly, for event C, the log-rank test found stronger evidence of reduction in hazard among those with ependymoma (p = 0.005) as compared with Gray's test (p = 0.086). Conclusions: To evaluate treatment differences, failing to account for competing risks using appropriate methodology may lead to incorrect interpretations.

  16. Competency Index. [Health Technology Cluster.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This competency index lists the competencies included in the 62 units of the Tech Prep Competency Profiles within the Health Technologies Cluster. The unit topics are as follows: employability skills; professionalism; teamwork; computer literacy; documentation; infection control and risk management; medical terminology; anatomy, physiology, and…

  17. Competent Psychopharmacology

    PubMed Central

    Gardner, David M

    2014-01-01

    There is little doubt that undergraduate and post-graduate training of physicians, pharmacists, and nurses is insufficient to prepare them to use psychotropics safely and effectively, especially in the context of their expanded off-label uses. Therefore, the development of competencies in psychotropic prescribing needs to be approached as a long-term, practice-based learning commitment. Proposed are the abilities and knowledge components necessary for safe and effective use of psychotropics. Typical challenges in prescribing for chronic and recurrent illnesses include highly variable responses and tolerability, drug interactions, and adverse effects that can be serious, irreversible, and even fatal. Prescribing psychotropics is further complicated by negative public and professional reports and growing patient concerns about the quality of care, and questions about the efficacy, safety, and addictive risks of psychotropics. Increased efforts are needed to enhance clinical training and knowledge in psychopharmacology among trainees and practising clinicians, with more comprehensive and sustained attention to the assessment of individual patients, and greater reliance on patient education and collaboration. Improved competence in psychotropic prescribing should lead to more informed, thoughtful, and better-targeted applications as one component of more comprehensive clinical care. PMID:25161064

  18. Competent psychopharmacology.

    PubMed

    Gardner, David M

    2014-08-01

    There is little doubt that undergraduate and post-graduate training of physicians, pharmacists, and nurses is insufficient to prepare them to use psychotropics safely and effectively, especially in the context of their expanded off-label uses. Therefore, the development of competencies in psychotropic prescribing needs to be approached as a long-term, practice-based learning commitment. Proposed are the abilities and knowledge components necessary for safe and effective use of psychotropics. Typical challenges in prescribing for chronic and recurrent illnesses include highly variable responses and tolerability, drug interactions, and adverse effects that can be serious, irreversible, and even fatal. Prescribing psychotropics is further complicated by negative public and professional reports and growing patient concerns about the quality of care, and questions about the efficacy, safety, and addictive risks of psychotropics. Increased efforts are needed to enhance clinical training and knowledge in psychopharmacology among trainees and practising clinicians, with more comprehensive and sustained attention to the assessment of individual patients, and greater reliance on patient education and collaboration. Improved competence in psychotropic prescribing should lead to more informed, thoughtful, and better-targeted applications as one component of more comprehensive clinical care.

  19. [Dealing with competing events in survival analysis].

    PubMed

    Béchade, Clémence; Lobbedez, Thierry

    2015-04-01

    Survival analyses focus on the occurrences of an event of interest, in order to determine risk factors and estimate a risk. Competing events prevent from observing the event of interest. If there are competing events, it can lead to a bias in the risk's estimation. The aim of this article is to explain why Cox model is not appropriate when there are competing events, and to present Fine and Gray model, which can help when dealing with competing risks.

  20. Analyzing Factors Affecting Emergency Department Length of Stay-Using a Competing Risk-accelerated Failure Time Model.

    PubMed

    Chaou, Chung-Hsien; Chiu, Te-Fa; Yen, Amy Ming-Fang; Ng, Chip-Jin; Chen, Hsiu-Hsi

    2016-04-01

    Emergency department (ED) length of stay (LOS) is associated with ED crowding and related complications. Previous studies either analyzed single patient disposition groups or combined different endpoints as a whole. The aim of this study is to evaluate different effects of relevant factors affecting ED LOS among different patient disposition groups.This is a retrospective electronic data analysis. The ED LOS and relevant covariates of all patients between January 2013 and December 2013 were collected. A competing risk accelerated failure time model was used to compute endpoint type-specific time ratios (TRs) for ED LOS.A total of 149,472 patients was included for analysis with an overall medium ED LOS of 2.15 [interquartile range (IQR) = 6.51] hours. The medium LOS for discharged, admission, and mortality patients was 1.46 (IQR = 2.07), 11.3 (IQR = 33.2), and 7.53 (IQR = 28.0) hours, respectively. In multivariate analysis, age (TR = 1.012, P < 0.0001], higher acuity (triage level I vs level V, TR = 2.371, P < 0.0001), pediatric nontrauma (compared with adult nontrauma, TR = 3.084, P < 0.0001), transferred patients (TR = 2.712, P < 0.0001), and day shift arrival (compared with night shift, TR = 1.451, P < 0.0001) were associated with prolonged ED LOS in the discharged patient group. However, opposite results were noted for higher acuity (triage level I vs level V, TR = 0.532, P < 0.0001), pediatric nontrauma (TR = 0.375, P < 0.0001), transferred patients (TR = 0.852, P < 0.0001), and day shift arrival (TR = 0.88, P < 0.0001) in the admission patient group.Common influential factors such as age, patient entity, triage acuity level, or arrival time may have varying effects on different disposition groups of patients. These findings and the suggested model could be used for EDs to develop individually tailored approaches to minimize ED LOS and further improve ED crowding status

  1. Analyzing Factors Affecting Emergency Department Length of Stay—Using a Competing Risk-accelerated Failure Time Model

    PubMed Central

    Chaou, Chung-Hsien; Chiu, Te-Fa; Yen, Amy Ming-Fang; Ng, Chip-Jin; Chen, Hsiu-Hsi

    2016-01-01

    Abstract Emergency department (ED) length of stay (LOS) is associated with ED crowding and related complications. Previous studies either analyzed single patient disposition groups or combined different endpoints as a whole. The aim of this study is to evaluate different effects of relevant factors affecting ED LOS among different patient disposition groups. This is a retrospective electronic data analysis. The ED LOS and relevant covariates of all patients between January 2013 and December 2013 were collected. A competing risk accelerated failure time model was used to compute endpoint type-specific time ratios (TRs) for ED LOS. A total of 149,472 patients was included for analysis with an overall medium ED LOS of 2.15 [interquartile range (IQR) = 6.51] hours. The medium LOS for discharged, admission, and mortality patients was 1.46 (IQR = 2.07), 11.3 (IQR = 33.2), and 7.53 (IQR = 28.0) hours, respectively. In multivariate analysis, age (TR = 1.012, P < 0.0001], higher acuity (triage level I vs level V, TR = 2.371, P < 0.0001), pediatric nontrauma (compared with adult nontrauma, TR = 3.084, P < 0.0001), transferred patients (TR = 2.712, P < 0.0001), and day shift arrival (compared with night shift, TR = 1.451, P < 0.0001) were associated with prolonged ED LOS in the discharged patient group. However, opposite results were noted for higher acuity (triage level I vs level V, TR = 0.532, P < 0.0001), pediatric nontrauma (TR = 0.375, P < 0.0001), transferred patients (TR = 0.852, P < 0.0001), and day shift arrival (TR = 0.88, P < 0.0001) in the admission patient group. Common influential factors such as age, patient entity, triage acuity level, or arrival time may have varying effects on different disposition groups of patients. These findings and the suggested model could be used for EDs to develop individually tailored approaches to minimize ED LOS and further improve ED crowding

  2. Competing risks and the development of adaptive management plans for water resources: Field reconnaissance investigation of risks to fishes and other aquatic biota exposed to endocrine disrupting chemicals (edcs) in lake mead, Nevada USA

    USGS Publications Warehouse

    Linder, G.; Little, E.E.

    2009-01-01

    The analysis and characterization of competing risks for water resources rely on a wide spectrum of tools to evaluate hazards and risks associated with their management. For example, waters of the lower Colorado River stored in reservoirs such as Lake Mead present a wide range of competing risks related to water quantity and water quality. These risks are often interdependent and complicated by competing uses of source waters for sustaining biological resources and for supporting a range of agricultural, municipal, recreational, and industrial uses. USGS is currently conducting a series of interdisciplinary case-studies on water quality of Lake Mead and its source waters. In this case-study we examine selected constituents potentially entering the Lake Mead system, particularly endocrine disrupting chemicals (EDCs). Worldwide, a number of environmental EDCs have been identified that affect reproduction, development, and adaptive behaviors in a wide range of organisms. Many EDCs are minimally affected by current treatment technologies and occur in treated sewage effluents. Several EDCs have been detected in Lake Mead, and several substances have been identified that are of concern because of potential impacts to the aquatic biota, including the sport fishery of Lake Mead and endangered razorback suckers (Xyrauchen texanus) that occur in the Colorado River system. For example, altered biomarkers relevant to reproduction and thyroid function in fishes have been observed and may be predictive of impaired metabolism and development. Few studies, however, have addressed whether such EDC-induced responses observed in the field have an ecologically significant effect on the reproductive success of fishes. To identify potential linkages between EDCs and species of management concern, the risk analysis and characterization in this reconnaissance study focused on effects (and attendant uncertainties) that might be expressed by exposed populations. In addition, risk reduction

  3. Serum 25-hydroxyvitamin D levels and incident diabetes mellitus type 2: a competing risk analysis in a large population-based cohort of older adults.

    PubMed

    Schöttker, Ben; Herder, Christian; Rothenbacher, Dietrich; Perna, Laura; Müller, Heiko; Brenner, Hermann

    2013-03-01

    Plausible mechanisms of how vitamin D deficiency may contribute to the development of diabetes mellitus have been proposed but longitudinal cohort studies have yielded heterogeneous results. In 7,791 initially diabetes-free participants of a German population-based cohort, aged 50-74 years, adjusted Cox regression models were employed to estimate hazard ratios (HR) with 95 % confidence intervals (CI) for the association of serum 25-hydroxyvitamin D (25(OH)D) quintiles and incident diabetes. Dose-response relationships were assessed with restricted cubic spline curves. Additionally, analyses accounting for the competing risks of diabetes and death were performed. During 8 years of follow-up, 829 study participants developed diabetes. In women, diabetes risk was significantly increased in the lowest 25(OH)D quintile (HR, 1.38; 1.09-1.75) and non-significantly increased in the 2nd quintile (HR, 1.24; 0.98-1.55) compared to women in 25(OH)D quintiles 3-5. The dose-response relationship showed a non-linear inverse association with risk starting to increase at 25(OH)D levels below 70 nmol/L (statistically significant: below 40 nmol/L). In men, 25(OH)D levels were not associated with diabetes incidence. Renal dysfunction was an effect modifier with a more than doubled diabetes risk in 25(OH)D quintile 1 and an about 1.5-fold risk in quintile 2 compared to quintiles 3-5 if subjects had renal dysfunction. The observed associations were not influenced by the competing risk of death. In this large cohort study of older adults, serum 25(OH)D levels were inversely associated with incident diabetes in women but not in men. The association was particularly strong in subjects with renal dysfunction.

  4. Professional Development for ECEC Practitioners with Responsibilities for Children at Risk: Which Competences and In-Service Training Are Needed?

    ERIC Educational Resources Information Center

    Peeters, Jan; Sharmahd, Nima

    2014-01-01

    There is growing evidence among researchers and international organisations that quality of Early Childhood Education and Care (ECEC), and ultimately the outcomes for children and families--especially disadvantaged ones--is dependent on well-educated and competent staff, and that a lack of higher pre-service training can be partly compensated by…

  5. Sex Offender Situational Competency Test (SOSCT) Pretreatment and Posttreatment Effects for Inpatient Sex Offenders in Hypothetical High-Risk Situations

    ERIC Educational Resources Information Center

    Reddon, John R.; Takacs, Shelly; Hogan, Stephen

    2013-01-01

    The purpose of the study was to evaluate relapse prevention skill acquisition within the context of a comprehensive treatment program involving group psychotherapy, relapse prevention programming, and other essential psychoeducational components. The Sex Offender Situational Competency Test (SOSCT) was administered pretreatment and posttreatment…

  6. Linking the Prevention of Problem Behaviors and Positive Youth Development: Core Competencies for Positive Youth Development and Risk Prevention

    ERIC Educational Resources Information Center

    Guerra, Nancy G.; Bradshaw, Catherine P.

    2008-01-01

    In this chapter, we present a brief review of the developmental literature linking healthy adjustment to five core competencies: (1) positive sense of self, (2) self-control, (3) decision-making skills, (4) a moral system of belief, and (5) prosocial connectedness. A central premise of this chapter and the rest of the volume is that promoting…

  7. Parametric Powder Diffraction

    NASA Astrophysics Data System (ADS)

    David, William I. F.; Evans, John S. O.

    The rapidity with which powder diffraction data may be collected, not only at neutron and X-ray synchrotron facilities but also in the laboratory, means that the collection of a single diffraction pattern is now the exception rather than the rule. Many experiments involve the collection of hundreds and perhaps many thousands of datasets where a parameter such as temperature or pressure is varied or where time is the variable and life-cycle, synthesis or decomposition processes are monitored or three-dimensional space is scanned and the three-dimensional internal structure of an object is elucidated. In this paper, the origins of parametric diffraction are discussed and the techniques and challenges of parametric powder diffraction analysis are presented. The first parametric measurements were performed around 50 years ago with the development of a modified Guinier camera but it was the automation afforded by neutron diffraction combined with increases in computer speed and memory that established parametric diffraction on a strong footing initially at the ILL, Grenoble in France. The theoretical parameterisation of quantities such as lattice constants and atomic displacement parameters will be discussed and selected examples of parametric diffraction over the past 20 years will be reviewed that highlight the power of the technique.

  8. Competing Uses of Underground Systems Related to Energy Supply: Applying Single- and Multiphase Simulations for Site Characterization and Risk-Analysis

    NASA Astrophysics Data System (ADS)

    Kissinger, A.; Walter, L.; Darcis, M.; Flemisch, B.; Class, H.

    2012-04-01

    Global climate change, shortage of resources and the resulting turn towards renewable sources of energy lead to a growing demand for the utilization of subsurface systems. Among these competing uses are Carbon Capture and Storage (CCS), geothermal energy, nuclear waste disposal, "renewable" methane or hydrogen storage as well as the ongoing production of fossil resources like oil, gas, and coal. Besides competing among themselves, these technologies may also create conflicts with essential public interests like water supply. For example, the injection of CO2 into the underground causes an increase in pressure reaching far beyond the actual radius of influence of the CO2 plume, potentially leading to large amounts of displaced salt water. Finding suitable sites is a demanding task for several reasons. Natural systems as opposed to technical systems are always characterized by heterogeneity. Therefore, parameter uncertainty impedes reliable predictions towards capacity and safety of a site. State of the art numerical simulations combined with stochastic approaches need to be used to obtain a more reliable assessment of the involved risks and the radii of influence of the different processes. These simulations may include the modeling of single- and multiphase non-isothermal flow, geo-chemical and geo-mechanical processes in order to describe all relevant physical processes adequately. Stochastic approaches have the aim to estimate a bandwidth of the key output parameters based on uncertain input parameters. Risks for these different underground uses can then be made comparable with each other. Along with the importance and the urgency of the competing processes this may lead to a more profound basis for a decision. Communicating risks to stake holders and a concerned public is crucial for the success of finding a suitable site for CCS (or other subsurface utilization). We present and discuss first steps towards an approach for addressing the issue of competitive

  9. Toward core inter-professional health promotion competencies to address the non-communicable diseases and their risk factors through knowledge translation: Curriculum content assessment

    PubMed Central

    2014-01-01

    Background To increase the global impact of health promotion related to non-communicable diseases, health professionals need evidence-based core competencies in health assessment and lifestyle behavior change. Assessment of health promotion curricula by health professional programs is a first step. Such program assessment is a means of 1. demonstrating collective commitment across health professionals to prevent non-communicable diseases; 2. addressing the knowledge translation gap between what is known about non-communicable diseases and their risk factors consistent with ‘best’ practice; and, 3. establishing core health-based competencies in the entry-level curricula of established health professions. Discussion Consistent with the World Health Organization’s definition of health (i.e., physical, emotional and social wellbeing) and the Ottawa Charter, health promotion competencies are those that support health rather than reduce signs and symptoms primarily. A process algorithm to guide the implementation of health promotion competencies by health professionals is described. The algorithm outlines steps from the initial assessment of a patient’s/client’s health and the indications for health behavior change, to the determination of whether that health professional assumes primary responsibility for implementing health behavior change interventions or refers the patient/client to others. An evidence-based template for assessment of the health promotion curriculum content of health professional education programs is outlined. It includes clinically-relevant behavior change theory; health assessment/examination tools; and health behavior change strategies/interventions that can be readily integrated into health professionals’ practices. Summary Assessment of the curricula in health professional education programs with respect to health promotion competencies is a compelling and potentially cost-effective initial means of preventing and reversing non

  10. DWPF welder parametric study

    SciTech Connect

    Eberhard, B.J.; Harbour, J.R.; Plodinec, M.J.

    1994-06-01

    As part of the DWPF Startup Test Program, a parametric study has been performed to determine a range of welder operating parameters which will produce acceptable final welds for canistered waste forms. The parametric window of acceptable welds defined by this study is 90,000 {plus_minus} 15,000 lb of force, 248,000 {plus_minus} 22,000 amps of current, and 95 {plus_minus} 15 cycles (@ 60 cops) for the time of application of the current.

  11. On the Importance of Accounting for Competing Risks in Pediatric Brain Cancer: II. Regression Modeling and Sample Size

    SciTech Connect

    Tai, Bee-Choo; Grundy, Richard; Machin, David

    2011-03-15

    Purpose: To accurately model the cumulative need for radiotherapy in trials designed to delay or avoid irradiation among children with malignant brain tumor, it is crucial to account for competing events and evaluate how each contributes to the timing of irradiation. An appropriate choice of statistical model is also important for adequate determination of sample size. Methods and Materials: We describe the statistical modeling of competing events (A, radiotherapy after progression; B, no radiotherapy after progression; and C, elective radiotherapy) using proportional cause-specific and subdistribution hazard functions. The procedures of sample size estimation based on each method are outlined. These are illustrated by use of data comparing children with ependymoma and other malignant brain tumors. The results from these two approaches are compared. Results: The cause-specific hazard analysis showed a reduction in hazards among infants with ependymoma for all event types, including Event A (adjusted cause-specific hazard ratio, 0.76; 95% confidence interval, 0.45-1.28). Conversely, the subdistribution hazard analysis suggested an increase in hazard for Event A (adjusted subdistribution hazard ratio, 1.35; 95% confidence interval, 0.80-2.30), but the reduction in hazards for Events B and C remained. Analysis based on subdistribution hazard requires a larger sample size than the cause-specific hazard approach. Conclusions: Notable differences in effect estimates and anticipated sample size were observed between methods when the main event showed a beneficial effect whereas the competing events showed an adverse effect on the cumulative incidence. The subdistribution hazard is the most appropriate for modeling treatment when its effects on both the main and competing events are of interest.

  12. Competencies of the Competent Recruiter.

    ERIC Educational Resources Information Center

    Beebe, Bill

    1996-01-01

    Outlines the various skills, behaviors, attitudes, and other qualities needed for the competent hiring of employees. Emphasizes that knowledge, a model for human resource development, experience, and difference competencies are essential to the hiring process. Lists 35 human resource development competencies, grouped under the headings of…

  13. Wolfenstein parametrization reexamined

    SciTech Connect

    Xing, Z. )

    1995-04-01

    The Wolfenstein parametrization of the 3[times]3 Kobayashi-Maskawa (KM) matrix [ital V] is modified by keeping its unitarity up to an accuracy of [ital O]([lambda][sup 6]). This modification can self-consistently lead to the off-diagonal asymmetry of [ital V], [vert bar][ital V][sub [ital i][ital j

  14. Joint modeling of longitudinal ordinal data and competing risks survival times and analysis of the NINDS rt-PA stroke trial

    PubMed Central

    Li, Ning; Elashoff, Robert M.; Li, Gang; Saver, Jeffrey

    2009-01-01

    SUMMARY Existing joint models for longitudinal and survival data are not applicable for longitudinal ordinal outcomes with possible non-ignorable missing values caused by multiple reasons. We propose a joint model for longitudinal ordinal measurements and competing risks failure time data, in which a partial proportional odds model for the longitudinal ordinal outcome is linked to the event times by latent random variables. At the survival endpoint, our model adopts the competing risks framework to model multiple failure types at the same time. The partial proportional odds model, as an extension of the popular proportional odds model for ordinal outcomes, is more flexible and at the same time provides a tool to test the proportional odds assumption. We use a likelihood approach and derive an EM algorithm to obtain the maximum likelihood estimates of the parameters. We further show that all the parameters at the survival endpoint are identifiable from the data. Our joint model enables one to make inference for both the longitudinal ordinal outcome and the failure times simultaneously. In addition, the inference at the longitudinal endpoint is adjusted for possible non-ignorable missing data caused by the failure times. We apply the method to the NINDS rt-PA stroke trial. Our study considers the modified Rankin Scale only. Other ordinal outcomes in the trial, such as the Barthel and Glasgow scales can be treated in the same way. PMID:19943331

  15. A semi-parametric approach to estimate risk functions associated with multi-dimensional exposure profiles: application to smoking and lung cancer

    PubMed Central

    2013-01-01

    Background A common characteristic of environmental epidemiology is the multi-dimensional aspect of exposure patterns, frequently reduced to a cumulative exposure for simplicity of analysis. By adopting a flexible Bayesian clustering approach, we explore the risk function linking exposure history to disease. This approach is applied here to study the relationship between different smoking characteristics and lung cancer in the framework of a population based case control study. Methods Our study includes 4658 males (1995 cases, 2663 controls) with full smoking history (intensity, duration, time since cessation, pack-years) from the ICARE multi-centre study conducted from 2001-2007. We extend Bayesian clustering techniques to explore predictive risk surfaces for covariate profiles of interest. Results We were able to partition the population into 12 clusters with different smoking profiles and lung cancer risk. Our results confirm that when compared to intensity, duration is the predominant driver of risk. On the other hand, using pack-years of cigarette smoking as a single summary leads to a considerable loss of information. Conclusions Our method estimates a disease risk associated to a specific exposure profile by robustly accounting for the different dimensions of exposure and will be helpful in general to give further insight into the effect of exposures that are accumulated through different time patterns. PMID:24152389

  16. Parametric resonance in DNA.

    PubMed

    Lacitignola, Deborah; Saccomandi, Giuseppe

    2014-03-01

    We consider a simple mesoscopic model of DNA in which the binding of the RNA polymerase enzyme molecule to the promoter sequence of the DNA is included through a substrate energy term modeling the enzymatic interaction with the DNA strands. We focus on the differential system for solitary waves and derive conditions--in terms of the model parameters--for the occurrence of the parametric resonance phenomenon. We find that what truly matters for parametric resonance is not the ratio between the strength of the stacking and the inter-strand forces but the ratio between the substrate and the inter-strands. On the basis of these results, the standard objection that longitudinal motion is negligible because of the second order seems to fail, suggesting that all the studies involving the longitudinal degree of freedom in DNA should be reconsidered when the interaction of the RNA polymerase with the DNA macromolecule is not neglected. PMID:24510728

  17. Parametric Explosion Spectral Model

    SciTech Connect

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  18. Elderly Peritoneal Dialysis Compared with Elderly Hemodialysis Patients and Younger Peritoneal Dialysis Patients: Competing Risk Analysis of a Korean Prospective Cohort Study

    PubMed Central

    Kim, Hyunsuk; An, Jung Nam; Kim, Dong Ki; Kim, Myoung-Hee; Kim, Ho; Kim, Yong-Lim; Park, Ki Soo; Oh, Yun Kyu; Lim, Chun Soo; Kim, Yon Su; Lee, Jung Pyo

    2015-01-01

    The outcomes of peritoneal dialysis (PD) in elderly patients have not been thoroughly investigated. We aimed to investigate the clinical outcomes and risk factors associated with PD in elderly patients. We conducted a prospective observational nationwide adult end-stage renal disease (ESRD) cohort study in Korea from August 2008 to March 2013. Among incident patients (n = 830), patient and technical survival rate, quality of life, and Beck’s Depression Inventory (BDI) scores of elderly PD patients (≥65 years, n = 95) were compared with those of PD patients aged ≤49 years (n = 205) and 50~64 years (n = 192); and elderly hemodialysis (HD) patients (n = 315). The patient death and technical failure were analyzed by cumulative incidence function. Competing risk regressions were used to assess the risk factors for survival. The patient survival rate of elderly PD patients was inferior to that of younger PD patients (P<0.001). However, the technical survival rate was similar (P = 0.097). Compared with elderly HD patients, the patient survival rate did not differ according to dialysis modality (P = 0.987). Elderly PD patients showed significant improvement in the BDI scores, as compared with the PD patients aged ≤49 years (P = 0.003). Low albumin, diabetes and low residual renal function were significant risk factors for the PD patient survival; and peritonitis was a significant risk factor for technical survival. Furthermore, low albumin and hospitalization were significant risk factors of patient survival among the elderly. The overall outcomes were similar between elderly PD and HD patients. PD showed the benefit in BDI and quality of life in the elderly. Additionally, the technical survival rate of elderly PD patients was similar to that of younger PD patients. Taken together, PD may be a comparable modality for elderly ESRD patients. PMID:26121574

  19. Elderly Peritoneal Dialysis Compared with Elderly Hemodialysis Patients and Younger Peritoneal Dialysis Patients: Competing Risk Analysis of a Korean Prospective Cohort Study.

    PubMed

    Kim, Hyunsuk; An, Jung Nam; Kim, Dong Ki; Kim, Myoung-Hee; Kim, Ho; Kim, Yong-Lim; Park, Ki Soo; Oh, Yun Kyu; Lim, Chun Soo; Kim, Yon Su; Lee, Jung Pyo

    2015-01-01

    The outcomes of peritoneal dialysis (PD) in elderly patients have not been thoroughly investigated. We aimed to investigate the clinical outcomes and risk factors associated with PD in elderly patients. We conducted a prospective observational nationwide adult end-stage renal disease (ESRD) cohort study in Korea from August 2008 to March 2013. Among incident patients (n = 830), patient and technical survival rate, quality of life, and Beck's Depression Inventory (BDI) scores of elderly PD patients (≥65 years, n = 95) were compared with those of PD patients aged ≤49 years (n = 205) and 50~64 years (n = 192); and elderly hemodialysis (HD) patients (n = 315). The patient death and technical failure were analyzed by cumulative incidence function. Competing risk regressions were used to assess the risk factors for survival. The patient survival rate of elderly PD patients was inferior to that of younger PD patients (P<0.001). However, the technical survival rate was similar (P = 0.097). Compared with elderly HD patients, the patient survival rate did not differ according to dialysis modality (P = 0.987). Elderly PD patients showed significant improvement in the BDI scores, as compared with the PD patients aged ≤49 years (P = 0.003). Low albumin, diabetes and low residual renal function were significant risk factors for the PD patient survival; and peritonitis was a significant risk factor for technical survival. Furthermore, low albumin and hospitalization were significant risk factors of patient survival among the elderly. The overall outcomes were similar between elderly PD and HD patients. PD showed the benefit in BDI and quality of life in the elderly. Additionally, the technical survival rate of elderly PD patients was similar to that of younger PD patients. Taken together, PD may be a comparable modality for elderly ESRD patients.

  20. Elderly Peritoneal Dialysis Compared with Elderly Hemodialysis Patients and Younger Peritoneal Dialysis Patients: Competing Risk Analysis of a Korean Prospective Cohort Study.

    PubMed

    Kim, Hyunsuk; An, Jung Nam; Kim, Dong Ki; Kim, Myoung-Hee; Kim, Ho; Kim, Yong-Lim; Park, Ki Soo; Oh, Yun Kyu; Lim, Chun Soo; Kim, Yon Su; Lee, Jung Pyo

    2015-01-01

    The outcomes of peritoneal dialysis (PD) in elderly patients have not been thoroughly investigated. We aimed to investigate the clinical outcomes and risk factors associated with PD in elderly patients. We conducted a prospective observational nationwide adult end-stage renal disease (ESRD) cohort study in Korea from August 2008 to March 2013. Among incident patients (n = 830), patient and technical survival rate, quality of life, and Beck's Depression Inventory (BDI) scores of elderly PD patients (≥65 years, n = 95) were compared with those of PD patients aged ≤49 years (n = 205) and 50~64 years (n = 192); and elderly hemodialysis (HD) patients (n = 315). The patient death and technical failure were analyzed by cumulative incidence function. Competing risk regressions were used to assess the risk factors for survival. The patient survival rate of elderly PD patients was inferior to that of younger PD patients (P<0.001). However, the technical survival rate was similar (P = 0.097). Compared with elderly HD patients, the patient survival rate did not differ according to dialysis modality (P = 0.987). Elderly PD patients showed significant improvement in the BDI scores, as compared with the PD patients aged ≤49 years (P = 0.003). Low albumin, diabetes and low residual renal function were significant risk factors for the PD patient survival; and peritonitis was a significant risk factor for technical survival. Furthermore, low albumin and hospitalization were significant risk factors of patient survival among the elderly. The overall outcomes were similar between elderly PD and HD patients. PD showed the benefit in BDI and quality of life in the elderly. Additionally, the technical survival rate of elderly PD patients was similar to that of younger PD patients. Taken together, PD may be a comparable modality for elderly ESRD patients. PMID:26121574

  1. Parametric Instabilities in Brusselator Reaction-Diffusion Systems

    NASA Astrophysics Data System (ADS)

    Geislinger, Brian; Purnell, Moriel; Kawai, Ryoichi

    2002-10-01

    We investigate the effects of a time-periodic parametric perturbation to a reaction diffusion system based on the Brusselator. The system becomes unstable when the pertubation frequency satisfies usual parametric resonance condition, and remains stable when the perturbation is out of resonance. When the perturbation is randomly inhomogenous, instabilites at these resonance frequencies form spatial patterns in parameter regions where the unperturbed system would be stable. However, these same patterns can be destroyed if the perturbation is homogeneous. These numerical results can be explained by two competing types of synchronizations - synchronization between neighbors (mutual synchronization) and synchronization to the perturbation (modulation synchronization).

  2. The influence of the perceived consequences of refusing to share injection equipment among injection drug users: Balancing competing risks

    PubMed Central

    Wagner, Karla D.; Lankenau, Stephen E.; Palinkas, Lawrence A.; Richardson, Jean L.; Chou, Chih-Ping; Unger, Jennifer B.

    2011-01-01

    Injection drug users (IDUs) are at risk for HIV and other bloodborne pathogens through receptive syringe sharing (RSS) and receptive paraphernalia sharing (RPS). Research into the influence of the perceived risk of HIV infection on injection risk behavior has yielded mixed findings. One explanation may be that consequences other than HIV infection are considered when IDUs are faced with decisions about whether or not to share equipment. We investigated the perceived consequences of refusing to share injection equipment among 187 IDUs recruited from a large syringe exchange program in Los Angeles, California, assessed their influence on RSS and RPS, and evaluated gender differences. Two sub-scales of perceived consequences were identified: structural/external consequences and social/internal consequences. In multiple linear regression, the perceived social/internal consequences of refusing to share were associated with both RSS and RPS, after controlling for other psychosocial constructs and demographic variables. Few statistically significant gender differences emerged. Assessing the consequences of refusing to share injection equipment may help explain persistent injection risk behavior, and may provide promising targets for comprehensive intervention efforts designed to address both individual and structural risk factors. PMID:21498004

  3. Setting priorities for private land conservation in fire-prone landscapes: Are fire risk reduction and biodiversity conservation competing or compatible objectives?

    USGS Publications Warehouse

    Syphard, Alexandra D.; Butsic, Van; Bar-Massada, Avi; Keeley, Jon E.; Tracey, Jeff A.; Fisher, Robert N.

    2016-01-01

    Although wildfire plays an important role in maintaining biodiversity in many ecosystems, fire management to protect human assets is often carried out by different agencies than those tasked for conserving biodiversity. In fact, fire risk reduction and biodiversity conservation are often viewed as competing objectives. Here we explored the role of management through private land conservation and asked whether we could identify private land acquisition strategies that fulfill the mutual objectives of biodiversity conservation and fire risk reduction, or whether the maximization of one objective comes at a detriment to the other. Using a fixed budget and number of homes slated for development, we simulated 20 years of housing growth under alternative conservation selection strategies, and then projected the mean risk of fires destroying structures and the area and configuration of important habitat types in San Diego County, California, USA. We found clear differences in both fire risk projections and biodiversity impacts based on the way conservation lands are prioritized for selection, but these differences were split between two distinct groupings. If no conservation lands were purchased, or if purchases were prioritized based on cost or likelihood of development, both the projected fire risk and biodiversity impacts were much higher than if conservation lands were purchased in areas with high fire hazard or high species richness. Thus, conserving land focused on either of the two objectives resulted in nearly equivalent mutual benefits for both. These benefits not only resulted from preventing development in sensitive areas, but they were also due to the different housing patterns and arrangements that occurred as development was displaced from those areas. Although biodiversity conflicts may still arise using other fire management strategies, this study shows that mutual objectives can be attained through land-use planning in this region. These results likely

  4. Stimulated parametric emission microscopy

    NASA Astrophysics Data System (ADS)

    Isobe, Keisuke; Kataoka, Shogo; Murase, Rena; Watanabe, Wataru; Higashi, Tsunehito; Kawakami, Shigeki; Matsunaga, Sachihiro; Fukui, Kiichi; Itoh, Kazuyoshi

    2006-01-01

    We propose a novel microscopy technique based on the four-wave mixing (FWM) process that is enhanced by two-photon electronic resonance induced by a pump pulse along with stimulated emission induced by a dump pulse. A Ti:sapphire laser and an optical parametric oscillator are used as light sources for the pump and dump pulses, respectively. We demonstrate that our proposed FWM technique can be used to obtain a one-dimensional image of ethanol-thinned Coumarin 120 solution sandwiched between a hole-slide glass and a cover slip, and a two-dimensional image of a leaf of Camellia sinensis.

  5. Parametric Trace Slicing

    NASA Technical Reports Server (NTRS)

    Rosu, Grigore (Inventor); Chen, Feng (Inventor); Chen, Guo-fang; Wu, Yamei; Meredith, Patrick O. (Inventor)

    2014-01-01

    A program trace is obtained and events of the program trace are traversed. For each event identified in traversing the program trace, a trace slice of which the identified event is a part is identified based on the parameter instance of the identified event. For each trace slice of which the identified event is a part, the identified event is added to an end of a record of the trace slice. These parametric trace slices can be used in a variety of different manners, such as for monitoring, mining, and predicting.

  6. Parametric Hazard Function Estimation.

    1999-09-13

    Version 00 Phaze performs statistical inference calculations on a hazard function (also called a failure rate or intensity function) based on reported failure times of components that are repaired and restored to service. Three parametric models are allowed: the exponential, linear, and Weibull hazard models. The inference includes estimation (maximum likelihood estimators and confidence regions) of the parameters and of the hazard function itself, testing of hypotheses such as increasing failure rate, and checking ofmore » the model assumptions.« less

  7. Multipass optical parametric amplifier

    SciTech Connect

    Jeys, T.H.

    1996-08-01

    A compact, low-threshold, multipass optical parametric amplifier has been developed for the conversion of short-pulse (360-ps) 1064-nm Nd:YAG laser radiation into eye-safe 1572-nm radiation for laser ranging and radar applications. The amplifier had a threshold pump power of as low as 45{mu}J, and at three to four times this threshold pump power the amplifier converted 30{percent} of the input 1064-nm radiation into 1572-nm output radiation. {copyright} {ital 1996 Optical Society of America.}

  8. Combining parametric, semi-parametric, and non-parametric survival models with stacked survival models.

    PubMed

    Wey, Andrew; Connett, John; Rudser, Kyle

    2015-07-01

    For estimating conditional survival functions, non-parametric estimators can be preferred to parametric and semi-parametric estimators due to relaxed assumptions that enable robust estimation. Yet, even when misspecified, parametric and semi-parametric estimators can possess better operating characteristics in small sample sizes due to smaller variance than non-parametric estimators. Fundamentally, this is a bias-variance trade-off situation in that the sample size is not large enough to take advantage of the low bias of non-parametric estimation. Stacked survival models estimate an optimally weighted combination of models that can span parametric, semi-parametric, and non-parametric models by minimizing prediction error. An extensive simulation study demonstrates that stacked survival models consistently perform well across a wide range of scenarios by adaptively balancing the strengths and weaknesses of individual candidate survival models. In addition, stacked survival models perform as well as or better than the model selected through cross-validation. Finally, stacked survival models are applied to a well-known German breast cancer study.

  9. Topological transition of the parametric expression site of tumor suppressor inactivation as a marker evidence of environmental hormone-oriented cancer risk increase.

    PubMed

    Kodama, M; Murakami, M; Kodama, T

    1999-08-01

    The present study is an extension of our recent study in which we attempted statistical analysis of the data assembly of age-adjusted incidence rates (AAIRs) of a tumor without topological data manipulation for each of 20 individual tumors in scope, for each of 6 cancer registration areas in space, and for a period of early 1960's to mid 1980's in time. This time, a data assembly of log AAIR changes in time and space first passed through the process of topological data manipulation, and then underwent the sequential regression analysis so that we could assess the fitness of log AAIR changes either in space or in time to the equilibrium model of the law of mass action from the viewpoint of the interaction between oncogene activation and tumor suppressor gene inactivation. For the sake of comparison, the fitness of the cancer risk data to the equilibrium model was assessed in the framework of 3 sets of coordinates: a) the original (x org, y org) coordinates in which most of the log AAIR data assemblies in their data variations were classified as the oncogene activation type in the field of centripetal force (r seq=-1.000). b) The rect (X rect, Y rect) coordinates in which the log AAIR data assemblies were very often classified as the tumor suppressor gene inactivation type in the field of centrifugal force (r seq=+1.000). c) The para (X para, Y para) coordinates in which the log AAIR data assemblies were mostly classified as the intermediate type as regards the fitness to the equilibrium model. The rect-coordinates and the para-coordinates, 2 variants of angular rotation of the original coordinates, were so designed as to allow their X-axes to run each at a right angle and parallel to the regression line of the original pair data block. The results obtained were as follows: a) poor fitness of the log AAIR changes in space to the equilibrium model in the rect-coordinates was found in male breast cancer, male thyroid cancer, female esophageal cancer, female laryngeal

  10. Observing and Planning for Play and Competence.

    ERIC Educational Resources Information Center

    Neumann, Eva A.

    This paper presents a framework useful for preschool and elementary teachers in developing a basic understanding of competency and play and their interrelationship. Specific guidelines are given for observing and planning toward increasing opportunities for competency and play. Competency is viewed as consisting of growth, risk-taking, and a…

  11. Theme: Coping with Competencies.

    ERIC Educational Resources Information Center

    Brown, Daniel; And Others

    1989-01-01

    Consists of five articles on the topic of competencies in vocational agriculture. Topics covered include (1) competency-based instruction, (2) competencies for agricultural recordkeeping, (3) competencies in hydroponics, and (4) competencies in agribusiness. (CH)

  12. Nanoscale electromechanical parametric amplifier

    DOEpatents

    Aleman, Benjamin Jose; Zettl, Alexander

    2016-09-20

    This disclosure provides systems, methods, and apparatus related to a parametric amplifier. In one aspect, a device includes an electron source electrode, a counter electrode, and a pumping electrode. The electron source electrode may include a conductive base and a flexible conductor. The flexible conductor may have a first end and a second end, with the second end of the flexible conductor being coupled to the conductive base. A cross-sectional dimension of the flexible conductor may be less than about 100 nanometers. The counter electrode may be disposed proximate the first end of the flexible conductor and spaced a first distance from the first end of the flexible conductor. The pumping electrode may be disposed proximate a length of the flexible conductor and spaced a second distance from the flexible conductor.

  13. Mechanical Parametric Oscillations and Waves

    ERIC Educational Resources Information Center

    Dittrich, William; Minkin, Leonid; Shapovalov, Alexander S.

    2013-01-01

    Usually parametric oscillations are not the topic of general physics courses. Probably it is because the mathematical theory of this phenomenon is relatively complicated, and until quite recently laboratory experiments for students were difficult to implement. However parametric oscillations are good illustrations of the laws of physics and can be…

  14. Parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.; Crockett, Thomas W.; Nicol, David M.

    1993-01-01

    Binary dissection is widely used to partition non-uniform domains over parallel computers. This algorithm does not consider the perimeter, surface area, or aspect ratio of the regions being generated and can yield decompositions that have poor communication to computation ratio. Parametric Binary Dissection (PBD) is a new algorithm in which each cut is chosen to minimize load + lambda x(shape). In a 2 (or 3) dimensional problem, load is the amount of computation to be performed in a subregion and shape could refer to the perimeter (respectively surface) of that subregion. Shape is a measure of communication overhead and the parameter permits us to trade off load imbalance against communication overhead. When A is zero, the algorithm reduces to plain binary dissection. This algorithm can be used to partition graphs embedded in 2 or 3-d. Load is the number of nodes in a subregion, shape the number of edges that leave that subregion, and lambda the ratio of time to communicate over an edge to the time to compute at a node. An algorithm is presented that finds the depth d parametric dissection of an embedded graph with n vertices and e edges in O(max(n log n, de)) time, which is an improvement over the O(dn log n) time of plain binary dissection. Parallel versions of this algorithm are also presented; the best of these requires O((n/p) log(sup 3)p) time on a p processor hypercube, assuming graphs of bounded degree. How PBD is applied to 3-d unstructured meshes and yields partitions that are better than those obtained by plain dissection is described. Its application to the color image quantization problem is also discussed, in which samples in a high-resolution color space are mapped onto a lower resolution space in a way that minimizes the color error.

  15. Presuming Competence

    ERIC Educational Resources Information Center

    Biklen, Douglas; Burke, Jamie

    2006-01-01

    At least since the early 1990s, educators in inclusive schooling as well as scholars in Disability Studies have critiqued prevailing notions of intellectual ability and have suggested the importance of interpretive communities for constructing student competence (Biklen, 1990; Goode, 1992, 1994; Kliewer, 1998; Kluth, 2003; Linneman, 2001). This…

  16. Parametric Transformation Analysis

    NASA Technical Reports Server (NTRS)

    Gary, G. Allan

    2003-01-01

    Because twisted coronal features are important proxies for predicting solar eruptive events, and, yet not clearly understood, we present new results to resolve the complex, non-potential magnetic field configurations of active regions. This research uses free-form deformation mathematics to generate the associated coronal magnetic field. We use a parametric representation of the magnetic field lines such that the field lines can be manipulated to match the structure of EUV and SXR coronal loops. The objective is to derive sigmoidal magnetic field solutions which allows the beta greater than 1 regions to be included, aligned and non-aligned electric currents to be calculated, and the Lorentz force to be determined. The advantage of our technique is that the solution is independent of the unknown upper and side boundary conditions, allows non-vanishing magnetic forces, and provides a global magnetic field solution, which contains high- and low-beta regimes and is consistent with all the coronal images of the region. We show that the mathematical description is unique and physical.

  17. Parametric Mass Reliability Study

    NASA Technical Reports Server (NTRS)

    Holt, James P.

    2014-01-01

    The International Space Station (ISS) systems are designed based upon having redundant systems with replaceable orbital replacement units (ORUs). These ORUs are designed to be swapped out fairly quickly, but some are very large, and some are made up of many components. When an ORU fails, it is replaced on orbit with a spare; the failed unit is sometimes returned to Earth to be serviced and re-launched. Such a system is not feasible for a 500+ day long-duration mission beyond low Earth orbit. The components that make up these ORUs have mixed reliabilities. Components that make up the most mass-such as computer housings, pump casings, and the silicon board of PCBs-typically are the most reliable. Meanwhile components that tend to fail the earliest-such as seals or gaskets-typically have a small mass. To better understand the problem, my project is to create a parametric model that relates both the mass of ORUs to reliability, as well as the mass of ORU subcomponents to reliability.

  18. Parametric scramjet analysis

    NASA Astrophysics Data System (ADS)

    Choi, Jongseong

    The performance of a hypersonic flight vehicle will depend on existing materials and fuels; this work presents the performance of the ideal scramjet engine for three different combustion chamber materials and three different candidate fuels. Engine performance is explored by parametric cycle analysis for the ideal scramjet as a function of material maximum service temperature and the lower heating value of jet engine fuels. The thermodynamic analysis is based on the Brayton cycle as similarly employed in describing the performance of the ramjet, turbojet, and fanjet ideal engines. The objective of this work is to explore material operating temperatures and fuel possibilities for the combustion chamber of a scramjet propulsion system to show how they relate to scramjet performance and the seven scramjet engine parameters: specific thrust, fuel-to-air ratio, thrust-specific fuel consumption, thermal efficiency, propulsive efficiency, overall efficiency, and thrust flux. The information presented in this work has not been done by others in the scientific literature. This work yields simple algebraic equations for scramjet performance which are similar to that of the ideal ramjet, ideal turbojet and ideal turbofan engines.

  19. Parametric Equations, Maple, and Tubeplots.

    ERIC Educational Resources Information Center

    Feicht, Louis

    1997-01-01

    Presents an activity that establishes a graphical foundation for parametric equations by using a graphing output form called tubeplots from the computer program Maple. Provides a comprehensive review and exploration of many previously learned topics. (ASK)

  20. Extreme Levels of HbA1c Increase Incident ESRD Risk in Chinese Patients with Type 2 Diabetes: Competing Risk Analysis in National Cohort of Taiwan Diabetes Study

    PubMed Central

    Liu, Chiu-Shong; Huang, Chiu-Ching; Lin, Wen-Yuan; Chiang, Jen-Huai; Lin, Cheng-Chieh; Li, Tsai-Chung

    2015-01-01

    Background Whether HbA1c is a predictor of end-stage renal disease (ESRD) in type 2 diabetes patients remains unclear. This study evaluated relationship between HbA1c and ESRD in Chinese patients with type 2 diabetes. Methods Patients aged ≥ 30 years who were free of ESRD (n = 51 681) were included from National Diabetes Care Management Program from 2002–2003. Extended Cox proportional hazard model with competing risk of death served to evaluate association between HbA1c level and ESRD. Results A total of 2613 (5.06%) people developed ESRD during a follow-up period of 8.1 years. Overall incidence rate of ESRD was 6.26 per 1000 person-years. Patients with high levels of HbA1c had a high incidence rate of ESRD, from 4.29 for HbA1c of  6.0%–6.9% to 10.33 for HbA1c ≥ 10.0% per 1000 person-years. Patients with HbA1c < 6.0% particularly had a slightly higher ESRD incidence (4.34 per 1000 person-years) than those with HbA1c  of 6.0%–6.9%. A J-shaped relationship between HbA1c level and ESRD risk was observed. After adjustment, patients with HbA1c < 6.0% and ≥ 10.0% exhibited an increased risk of ESRD (HR: 1.99, 95% CI: 1.62–2.44; HR: 4.42, 95% CI: 3.80–5.14, respectively) compared with those with HbA1c of 6.0%–6.9%. Conclusions Diabetes care has focused on preventing hyperglycemia, but not hypoglycemia. Our study revealed that HbA1c level ≥ 7.0% was linked with increased ESRD risk in type 2 diabetes patients, and that HbA1c < 6.0% also had the potential to increase ESRD risk. Our study provides epidemiological evidence that appropriate glycemic control is essential for diabetes care to meet HbA1c targets and improve outcomes without increasing the risk to this population. Clinicians need to pay attention to HbA1c results on diabetic nephropathy. PMID:26098901

  1. Religious competence as cultural competence

    PubMed Central

    2012-01-01

    Definitions of cultural competence often refer to the need to be aware and attentive to the religious and spiritual needs and orientations of patients. However, the institution of psychiatry maintains an ambivalent attitude to the incorporation of religion and spirituality into psychiatric practice. This is despite the fact that many patients, especially those from underserved and underprivileged minority backgrounds, are devotedly religious and find much solace and support in their religiosity. I use the case of mental health of African Americans as an extended example to support the argument that psychiatric services must become more closely attuned to religious matters. I suggest ways in which this can be achieved. Attention to religion can aid in the development of culturally competent and accessible services, which in turn, may increase engagement and service satisfaction among religious populations. PMID:22421686

  2. Neighborhood socioeconomic deprivation, tumor subtypes, and causes of death after non-metastatic invasive breast cancer diagnosis: a multilevel competing-risk analysis.

    PubMed

    Lian, Min; Pérez, Maria; Liu, Ying; Schootman, Mario; Frisse, Ann; Foldes, Ellen; Jeffe, Donna B

    2014-10-01

    The purpose of this study is to examine the associations of neighborhood socioeconomic deprivation and triple-negative breast cancer (TNBC) subtype with causes of death [breast cancer (BC)-specific and non-BC-specific] among non-metastatic invasive BC patients. We identified 3,312 patients younger than 75 years (mean age 53.5 years; 621 [18.8 %] TNBC) with first primary BC treated at an academic medical center from 1999 to 2010. We constructed a census-tract-level socioeconomic deprivation index using the 2000 U.S. Census data and performed a multilevel competing-risk analysis to estimate the hazard ratios (HR) and 95 % confidence intervals (CI) of BC-specific and non-BC-specific mortality associated with neighborhood socioeconomic deprivation and TNBC subtype. The adjusted models controlled for patient sociodemographics, health behaviors, tumor characteristics, comorbidity, and cancer treatment. With a median 62-month follow-up, 349 (10.5 %) patients died; 233 died from BC. In the multivariate models, neighborhood socioeconomic deprivation was independently associated with non-BC-specific mortality (the most- vs. the least-deprived quartile: HR = 2.98, 95 % CI = 1.33-6.66); in contrast, its association with BC-specific mortality was explained by the aforementioned patient-level covariates, particularly sociodemographic factors (HR = 1.15, 95 % CI = 0.71-1.87). TNBC subtype was independently associated with non-BC-specific mortality (HR = 2.15; 95 % CI = 1.20-3.84), while the association between TNBC and BC-specific mortality approached significance (HR = 1.42; 95 % CI = 0.99-2.03, P = 0.057). Non-metastatic invasive BC patients who lived in more socioeconomically deprived neighborhoods were more likely to die as a result of causes other than BC compared with those living in the least socioeconomically deprived neighborhoods. TNBC was associated with non-BC-specific mortality but not BC-specific mortality.

  3. Joint modeling of repeated multivariate cognitive measures and competing risks of dementia and death: a latent process and latent class approach.

    PubMed

    Proust-Lima, Cécile; Dartigues, Jean-François; Jacqmin-Gadda, Hélène

    2016-02-10

    Joint models initially dedicated to a single longitudinal marker and a single time-to-event need to be extended to account for the rich longitudinal data of cohort studies. Multiple causes of clinical progression are indeed usually observed, and multiple longitudinal markers are collected when the true latent trait of interest is hard to capture (e.g., quality of life, functional dependency, and cognitive level). These multivariate and longitudinal data also usually have nonstandard distributions (discrete, asymmetric, bounded, etc.). We propose a joint model based on a latent process and latent classes to analyze simultaneously such multiple longitudinal markers of different natures, and multiple causes of progression. A latent process model describes the latent trait of interest and links it to the observed longitudinal outcomes using flexible measurement models adapted to different types of data, and a latent class structure links the longitudinal and cause-specific survival models. The joint model is estimated in the maximum likelihood framework. A score test is developed to evaluate the assumption of conditional independence of the longitudinal markers and each cause of progression given the latent classes. In addition, individual dynamic cumulative incidences of each cause of progression based on the repeated marker data are derived. The methodology is validated in a simulation study and applied on real data about cognitive aging obtained from a large population-based study. The aim is to predict the risk of dementia by accounting for the competing death according to the profiles of semantic memory measured by two asymmetric psychometric tests.

  4. Incorporating parametric uncertainty into population viability analysis models

    USGS Publications Warehouse

    McGowan, Conor P.; Runge, Michael C.; Larson, Michael A.

    2011-01-01

    Uncertainty in parameter estimates from sampling variation or expert judgment can introduce substantial uncertainty into ecological predictions based on those estimates. However, in standard population viability analyses, one of the most widely used tools for managing plant, fish and wildlife populations, parametric uncertainty is often ignored in or discarded from model projections. We present a method for explicitly incorporating this source of uncertainty into population models to fully account for risk in management and decision contexts. Our method involves a two-step simulation process where parametric uncertainty is incorporated into the replication loop of the model and temporal variance is incorporated into the loop for time steps in the model. Using the piping plover, a federally threatened shorebird in the USA and Canada, as an example, we compare abundance projections and extinction probabilities from simulations that exclude and include parametric uncertainty. Although final abundance was very low for all sets of simulations, estimated extinction risk was much greater for the simulation that incorporated parametric uncertainty in the replication loop. Decisions about species conservation (e.g., listing, delisting, and jeopardy) might differ greatly depending on the treatment of parametric uncertainty in population models.

  5. Parametric design using IGRIP

    SciTech Connect

    Baker, C.

    1994-10-01

    The Department of Energy`s (DOE) Hanford site near Richland, Washington is being cleaned up after 50 years of nuclear materials production. One of the most serious problems at the site is the waste stored in single-shell underground storage tanks. There are 149 of these tanks containing the spent fuel residue remaining after the fuel is dissolved in acid and the desired materials (primarily plutonium and uranium) are separated out. The tanks are upright cylinders 75 ft. in diameter with domed tops. They are made of reinforced concrete, have steel liners, and each tank is buried under 7--12 ft. of overburden. The tanks are up to 40-ft. high, and have capacities of 500,000, 750,000, or 1,000,000 gallons of waste. As many as one-third of these tanks are known or suspected to leak. The waste form contained in the tanks varies in consistency from liquid supernatant to peanut-butter-like gels and sludges to hard salt cake (perhaps as hard as low-grade concrete). The current waste retrieval plan is to insert a large long-reach manipulator through a hole cut in the top of the tank, and use a variety of end-effectors to mobilize the waste and remove it from the tank. PNL has, with the assistance of Deneb robotics employees, developed a means of using the IGRIP code to perform parametric design of mechanical systems. This method requires no modifications to the IGRIP code, and all design data are stored in the IGRIP workcell. The method is presented in the context of development of a passive articulated mechanism that is used to deliver down-arm services to a gantry robot. The method is completely general, however, and could be used to design a fully articulated manipulator. Briefly, the method involves using IGCALC expressions to control manipulator joint angles, and IGCALC variables to allow user control of link lengths and offsets. This paper presents the method in detail, with examples drawn from PNL`s experience with the gantry robot service-providing mechanism.

  6. Raman-Suppressing Coupling for Optical Parametric Oscillator

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Rubiola, Enrico

    2007-01-01

    A Raman-scattering-suppressing input/ output coupling scheme has been devised for a whispering-gallery-mode optical resonator that is used as a four-wave-mixing device to effect an all-optical parametric oscillator. Raman scattering is undesired in such a device because (1) it is a nonlinear process that competes with the desired nonlinear four-wave conversion process involved in optical parametric oscillation and (2) as such, it reduces the power of the desired oscillation and contributes to output noise. The essence of the present input/output coupling scheme is to reduce output loading of the desired resonator modes while increasing output loading of the undesired ones.

  7. Parametric infrared tunable laser system

    NASA Technical Reports Server (NTRS)

    Garbuny, M.; Henningsen, T.; Sutter, J. R.

    1980-01-01

    A parametric tunable infrared laser system was built to serve as transmitter for the remote detection and density measurement of pollutant, poisonous, or trace gases in the atmosphere. The system operates with a YAG:Nd laser oscillator amplifier chain which pumps a parametric tunable frequency converter. The completed system produced pulse energies of up to 30 mJ. The output is tunable from 1.5 to 3.6 micrometers at linewidths of 0.2-0.5 /cm (FWHM), although the limits of the tuning range and the narrower line crystals presently in the parametric converter by samples of the higher quality already demonstrated is expected to improve the system performance further.

  8. Competing-risk analysis of death and dialysis initiation among elderly (≥80 years) newly referred to nephrologists: a French prospective study

    PubMed Central

    2013-01-01

    Background Reasons underlying dialysis decision-making in Octogenarians and Nonagenarians have not been further explored in prospective studies. Methods This regional, multicentre, non-interventional and prospective study was aimed to describe characteristics and quality of life (QoL) of elderly (≥80 years of age) with advanced chronic kidney disease (stage 3b-5 CKD) newly referred to nephrologists. Predictive factors of death and dialysis initiation were also assessed using competing-risk analyses. Results All 155 included patients had an estimated glomerular filtration rate (eGFR) below 45 ml/min/1.73 m2. Most patients had a non anaemic haemoglobin level (Hb) with no iron deficiency, and normal calcium and phosphate levels. They were well-fed and had a normal cognitive function and a good QoL. The 3-year probabilities of death and dialysis initiation reached 27% and 11%, respectively. The leading causes of death were cardiovascular (32%), cachexia (18%), cancer (9%), infection (3%), trauma (3%), dementia (3%), and unknown (32%). The reasons for dialysis initiation were based on uncontrolled biological abnormalities, such as hyperkalemia or acidosis (71%), uncontrolled digestive disorders (35%), uncontrolled pulmonary or peripheral oedema (29%), and uncontrolled malnutrition (12%). No patients with acute congestive heart failure or cancer initiated dialysis. Predictors of death found in both multivariate regression models (Cox and Fine & Gray) included acute congestive heart failure, age, any walking impairment and Hb <10 g/dL. Regarding dialysis initiation, eGFR <23 mL/min/1.73 m2 was the only predictor found in the Cox multivariate regression model whereas eGFR <23 mL/min/1.73 m2 and diastolic blood pressure were both independently associated with dialysis initiation in the Fine & Gray analysis. Such findings suggested that death and dialysis were independent events. Conclusions Octogenarians and Nonagenarians newly referred to nephrologists by

  9. Computing Optimal Stochastic Portfolio Execution Strategies: A Parametric Approach Using Simulations

    NASA Astrophysics Data System (ADS)

    Moazeni, Somayeh; Coleman, Thomas F.; Li, Yuying

    2010-09-01

    Computing optimal stochastic portfolio execution strategies under appropriate risk consideration presents great computational challenge. We investigate a parametric approach for computing optimal stochastic strategies using Monte Carlo simulations. This approach allows reduction in computational complexity by computing coefficients for a parametric representation of a stochastic dynamic strategy based on static optimization. Using this technique, constraints can be similarly handled using appropriate penalty functions. We illustrate the proposed approach to minimize the expected execution cost and Conditional Value-at-Risk (CVaR).

  10. Future Directions for Research on Core Competencies

    ERIC Educational Resources Information Center

    Bradshaw, Catherine P.; Guerra, Nancy G.

    2008-01-01

    This concluding commentary highlights common themes that emerged across the chapters in this volume. We identify strengths and limitations of the core competencies framework and discuss the importance of context, culture, and development for understanding the role of the core competencies in preventing risk behavior in adolescence. We also outline…

  11. Frequency domain optical parametric amplification

    NASA Astrophysics Data System (ADS)

    Schmidt, Bruno E.; Thiré, Nicolas; Boivin, Maxime; Laramée, Antoine; Poitras, François; Lebrun, Guy; Ozaki, Tsuneyuki; Ibrahim, Heide; Légaré, François

    2014-05-01

    Today’s ultrafast lasers operate at the physical limits of optical materials to reach extreme performances. Amplification of single-cycle laser pulses with their corresponding octave-spanning spectra still remains a formidable challenge since the universal dilemma of gain narrowing sets limits for both real level pumped amplifiers as well as parametric amplifiers. We demonstrate that employing parametric amplification in the frequency domain rather than in time domain opens up new design opportunities for ultrafast laser science, with the potential to generate single-cycle multi-terawatt pulses. Fundamental restrictions arising from phase mismatch and damage threshold of nonlinear laser crystals are not only circumvented but also exploited to produce a synergy between increased seed spectrum and increased pump energy. This concept was successfully demonstrated by generating carrier envelope phase stable, 1.43 mJ two-cycle pulses at 1.8 μm wavelength.

  12. Experience with parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.

    1993-01-01

    Parametric Binary Dissection (PBD) is a new algorithm that can be used for partitioning graphs embedded in 2- or 3-dimensional space. It partitions explicitly on the basis of nodes + (lambda)x(edges cut), where lambda is the ratio of time to communicate over an edge to the time to compute at a node. The new algorithm is faster than the original binary dissection algorithm and attempts to obtain better partitions than the older algorithm, which only takes nodes into account. The performance of parametric dissection with plain binary dissection on 3 large unstructured 3-d meshes obtained from computational fluid dynamics and on 2 random graphs were compared. It was showm that the new algorithm can usually yield partitions that are substantially superior, but that its performance is heavily dependent on the input data.

  13. Frequency domain optical parametric amplification

    PubMed Central

    Schmidt, Bruno E.; Thiré, Nicolas; Boivin, Maxime; Laramée, Antoine; Poitras, François; Lebrun, Guy; Ozaki, Tsuneyuki; Ibrahim, Heide; Légaré, François

    2014-01-01

    Today’s ultrafast lasers operate at the physical limits of optical materials to reach extreme performances. Amplification of single-cycle laser pulses with their corresponding octave-spanning spectra still remains a formidable challenge since the universal dilemma of gain narrowing sets limits for both real level pumped amplifiers as well as parametric amplifiers. We demonstrate that employing parametric amplification in the frequency domain rather than in time domain opens up new design opportunities for ultrafast laser science, with the potential to generate single-cycle multi-terawatt pulses. Fundamental restrictions arising from phase mismatch and damage threshold of nonlinear laser crystals are not only circumvented but also exploited to produce a synergy between increased seed spectrum and increased pump energy. This concept was successfully demonstrated by generating carrier envelope phase stable, 1.43 mJ two-cycle pulses at 1.8 μm wavelength. PMID:24805968

  14. Parametric Modeling for Fluid Systems

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Martinez, Jonathan

    2013-01-01

    Fluid Systems involves different projects that require parametric modeling, which is a model that maintains consistent relationships between elements as is manipulated. One of these projects is the Neo Liquid Propellant Testbed, which is part of Rocket U. As part of Rocket U (Rocket University), engineers at NASA's Kennedy Space Center in Florida have the opportunity to develop critical flight skills as they design, build and launch high-powered rockets. To build the Neo testbed; hardware from the Space Shuttle Program was repurposed. Modeling for Neo, included: fittings, valves, frames and tubing, between others. These models help in the review process, to make sure regulations are being followed. Another fluid systems project that required modeling is Plant Habitat's TCUI test project. Plant Habitat is a plan to develop a large growth chamber to learn the effects of long-duration microgravity exposure to plants in space. Work for this project included the design and modeling of a duct vent for flow test. Parametric Modeling for these projects was done using Creo Parametric 2.0.

  15. Optically induced parametric magnetic resonances

    NASA Astrophysics Data System (ADS)

    Jimenez, Ricardo; Knappe, Svenja; Kitching, John

    2011-05-01

    Optically pumped vector magnetometers based on zero-field resonances have reached very high sensitivities by operating at high atomic densities where dephasing due to spin-exchange collisions can be suppressed. Simplified setups, with just one laser beam have measured magnetic fields from the human brain and heart. A key feature in these magnetometers is the introduction of an rf magnetic field along the measurement axis to generate a parametric resonance. Lock-in detection of the transmitted light, at an odd harmonic of the modulation frequency, allows the reduction of the low frequency noise and generates a resonance with dispersive shape. Here we study a zero-field vector magnetometer where the parametric resonances are induced by the vector AC stark-shift of light. This approach does not produce any external magnetic field that could disturb the reading of other magnetometers in the vicinity and could provide an alternative in applications where an applied AC-field cannot be used. We have characterized the vector AC stark-shift effect of light on Rb atoms contained in a micromachined vapor cell with buffer gas. We have obtained parametric resonances induced by modulation of the light-shift. We also analyze the detunings and intensities of the light-shift beam that maintain the magnetometer within the spin-exchange relaxation-free regime.

  16. Predictive Value of Beat-to-Beat QT Variability Index across the Continuum of Left Ventricular Dysfunction: Competing Risks of Non-cardiac or Cardiovascular Death, and Sudden or Non-Sudden Cardiac Death

    PubMed Central

    Tereshchenko, Larisa G.; Cygankiewicz, Iwona; McNitt, Scott; Vazquez, Rafael; Bayes-Genis, Antoni; Han, Lichy; Sur, Sanjoli; Couderc, Jean-Philippe; Berger, Ronald D.; de Luna, Antoni Bayes; Zareba, Wojciech

    2012-01-01

    Background The goal of this study was to determine the predictive value of beat-to-beat QT variability in heart failure (HF) patients across the continuum of left ventricular dysfunction. Methods and Results Beat-to-beat QT variability index (QTVI), heart rate variance (LogHRV), normalized QT variance (QTVN), and coherence between heart rate variability and QT variability have been measured at rest during sinus rhythm in 533 participants of the Muerte Subita en Insuficiencia Cardiaca (MUSIC) HF study (mean age 63.1±11.7; males 70.6%; LVEF >35% in 254 [48%]) and in 181 healthy participants from the Intercity Digital Electrocardiogram Alliance (IDEAL) database. During a median of 3.7 years of follow-up, 116 patients died, 52 from sudden cardiac death (SCD). In multivariate competing risk analyses, the highest QTVI quartile was associated with cardiovascular death [hazard ratio (HR) 1.67(95%CI 1.14-2.47), P=0.009] and in particular with non-sudden cardiac death [HR 2.91(1.69-5.01), P<0.001]. Elevated QTVI separated 97.5% of healthy individuals from subjects at risk for cardiovascular [HR 1.57(1.04-2.35), P=0.031], and non-sudden cardiac death in multivariate competing risk model [HR 2.58(1.13-3.78), P=0.001]. No interaction between QTVI and LVEF was found. QTVI predicted neither non-cardiac death (P=0.546) nor SCD (P=0.945). Decreased heart rate variability (HRV) rather than increased QT variability was the reason for increased QTVI in this study. Conclusions Increased QTVI due to depressed HRV predicts cardiovascular mortality and non-sudden cardiac death, but neither SCD nor excracardiac mortality in HF across the continuum of left ventricular dysfunction. Abnormally augmented QTVI separates 97.5% of healthy individuals from HF patients at risk. PMID:22730411

  17. Stimulated Parametric Emission Microscope Systems

    NASA Astrophysics Data System (ADS)

    Itoh, Kazuyoshi; Isobe, Keisuke

    2006-10-01

    We present a novel microscopy technique based on the fourwave mixing (FWM) process that is enhanced by two-photon electronic resonance induced by a pump pulse along with stimulated emission induced by a dump pulse. A Ti:sapphire laser and an optical parametric oscillator are used as light sources for the pump and dump pulses, respectively. We demonstrate that our FWM technique can be used to obtain two-dimensional microscopic images of an unstained leaf of Camellia sinensis and an unlabeled tobacco BY2 Cell.

  18. Parametric nanomechanical amplification at very high frequency.

    PubMed

    Karabalin, R B; Feng, X L; Roukes, M L

    2009-09-01

    Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach. PMID:19736969

  19. Parametric nanomechanical amplification at very high frequency.

    PubMed

    Karabalin, R B; Feng, X L; Roukes, M L

    2009-09-01

    Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach.

  20. Triminimal parametrization of quark mixing matrix

    NASA Astrophysics Data System (ADS)

    He, Xiao-Gang; Li, Shi-Wen; Ma, Bo-Qiang

    2008-12-01

    Starting from a new zeroth order basis for quark mixing (CKM) matrix based on the quark-lepton complementarity and the tribimaximal pattern of lepton mixing, we derive a triminimal parametrization of a CKM matrix with three small angles and a CP-violating phase as its parameters. This new triminimal parametrization has the merits of fast convergence and simplicity in application. With the quark-lepton complementary relations, we derive relations between the two unified triminimal parametrizations for quark mixing obtained in this work and for lepton mixing obtained by Pakvasa-Rodejohann-Weiler. Parametrization deviating from quark-lepton complementarity is also discussed.

  1. Analysis of parametric transformer with rectifier load

    SciTech Connect

    Ichinokura, O.; Jinzenji, T. ); Tajima, K. )

    1993-03-01

    This paper describes a push-pull parametric transformer constructed using a pair of orthogonal-cores. The operating characteristics of the parametric transformer with a rectifier load were analyzed based on SPICE simulations. The analysis results show good agreement with experiment. It was found that the input surge current of the full-wave rectifier circuit with a smoothing capacitor can be compensated by the parametric transformer. Use of the parametric transformer as a power stabilizer is anticipated owing to its various functions such as for voltage regulation and overload protection.

  2. Software for Managing Parametric Studies

    NASA Technical Reports Server (NTRS)

    Yarrow, Maurice; McCann, Karen M.; DeVivo, Adrian

    2003-01-01

    The Information Power Grid Virtual Laboratory (ILab) is a Practical Extraction and Reporting Language (PERL) graphical-user-interface computer program that generates shell scripts to facilitate parametric studies performed on the Grid. (The Grid denotes a worldwide network of supercomputers used for scientific and engineering computations involving data sets too large to fit on desktop computers.) Heretofore, parametric studies on the Grid have been impeded by the need to create control language scripts and edit input data files painstaking tasks that are necessary for managing multiple jobs on multiple computers. ILab reflects an object-oriented approach to automation of these tasks: All data and operations are organized into packages in order to accelerate development and debugging. A container or document object in ILab, called an experiment, contains all the information (data and file paths) necessary to define a complex series of repeated, sequenced, and/or branching processes. For convenience and to enable reuse, this object is serialized to and from disk storage. At run time, the current ILab experiment is used to generate required input files and shell scripts, create directories, copy data files, and then both initiate and monitor the execution of all computational processes.

  3. Competing Risk Analysis of Neurologic versus Nonneurologic Death in Patients Undergoing Radiosurgical Salvage After Whole-Brain Radiation Therapy Failure: Who Actually Dies of Their Brain Metastases?

    SciTech Connect

    Lucas, John T.; Colmer, Hentry G.; White, Lance; Fitzgerald, Nora; Isom, Scott; Bourland, John D.; Laxton, Adrian W.; Tatter, Stephen B.; Chan, Michael D.

    2015-08-01

    Purpose: To estimate the hazard for neurologic (central nervous system, CNS) and nonneurologic (non-CNS) death associated with patient, treatment, and systemic disease status in patients receiving stereotactic radiosurgery after whole-brain radiation therapy (WBRT) failure, using a competing risk model. Patients and Methods: Of 757 patients, 293 experienced recurrence or new metastasis following WBRT. Univariate Cox proportional hazards regression identified covariates for consideration in the multivariate model. Competing risks multivariable regression was performed to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI) for both CNS and non-CNS death after adjusting for patient, disease, and treatment factors. The resultant model was converted into an online calculator for ease of clinical use. Results: The cumulative incidence of CNS and non-CNS death at 6 and 12 months was 20.6% and 21.6%, and 34.4% and 35%, respectively. Patients with melanoma histology (relative to breast) (aHR 2.7, 95% CI 1.5-5.0), brainstem location (aHR 2.1, 95% CI 1.3-3.5), and number of metastases (aHR 1.09, 95% CI 1.04-1.2) had increased aHR for CNS death. Progressive systemic disease (aHR 0.55, 95% CI 0.4-0.8) and increasing lowest margin dose (aHR 0.97, 95% CI 0.9-0.99) were protective against CNS death. Patients with lung histology (aHR 1.3, 95% CI 1.1-1.9) and progressive systemic disease (aHR 2.14, 95% CI 1.5-3.0) had increased aHR for non-CNS death. Conclusion: Our nomogram provides individual estimates of neurologic death after salvage stereotactic radiosurgery for patients who have failed prior WBRT, based on histology, neuroanatomical location, age, lowest margin dose, and number of metastases after adjusting for their competing risk of death from other causes.

  4. Competencies: A New Sector.

    ERIC Educational Resources Information Center

    Brophy, Monica; Kiely, Tony

    2002-01-01

    Job analysis of managers in 42 Irish three-star hotels identified the following key management competencies and associated behavioral indicators. The results were used to develop a competency framework for management development. (Contains 29 references.) (SK)

  5. Acetabular revision with impaction bone grafting and a cemented polyethylene acetabular component: comparison of the Kaplan-Meier analysis to the competing risk analysis in 62 revisions with 25 to 30 years follow-up.

    PubMed

    Te Stroet, M A J; Keurentjes, J C; Rijnen, W H C; Gardeniers, J W M; Verdonschot, N; Slooff, T J J H; Schreurs, B W

    2015-10-01

    We present the results of 62 consecutive acetabular revisions using impaction bone grafting and a cemented polyethylene acetabular component in 58 patients (13 men and 45 women) after a mean follow-up of 27 years (25 to 30). All patients were prospectively followed. The mean age at revision was 59.2 years (23 to 82). We performed Kaplan-Meier (KM) analysis and also a Competing Risk (CR) analysis because with long-term follow-up, the presence of a competing event (i.e. death) prevents the occurrence of the endpoint of re-revision. A total of 48 patients (52 hips) had died or had been re-revised at final review in March 2011. None of the deaths were related to the surgery. The mean Harris hip score of the ten surviving hips in ten patients was 76 points (45 to 99). The KM survivorship at 25 years for the endpoint 're-revision for any reason' was 58.0% (95% confidence interval (CI) 38 to 73) and for 're-revision for aseptic loosening' 72.1% (95% CI 51 to 85). With the CR analysis we calculated the KM analysis overestimates the failure rate with respectively 74% and 93% for these endpoints. The current study shows that acetabular impaction bone grafting revisions provide good clinical results at over 25 years.

  6. [Competence in Young Children.

    ERIC Educational Resources Information Center

    White, Burton L.

    Four papers discuss the Harvard Preschool Project whose goal is to learn how to structure the experiences of the first six years of life to encourage maximal development of human competence. To determine what competence at age 6 is, a group of 13 highly competent 6-year-olds of mixed residence, class, and ethnicity were compared to a like group of…

  7. Competencies in HRD. Symposium.

    ERIC Educational Resources Information Center

    2002

    This symposium is comprised of three papers on competencies in human resource development (HRD). "The Development of a Competency Model and Assessment Instrument for Public Sector Leadership and Management Development" (Sharon S. Naquin, Elwood F. Holton III) reports on a streamlined methodology and process used to develop a competency model for…

  8. Competencies in Professional Psychology

    ERIC Educational Resources Information Center

    Kaslow, Nadine J.

    2004-01-01

    There has been a burgeoning interest in competency-based education and credentialing in professional psychology. This movement gained momentum at the Competencies Conference: Future Directions in Education and Credentialing in Professional Psychology. After defining professional competence, the author focuses on the identification and delineation…

  9. Do Students Expect Compensation for Wage Risk?

    ERIC Educational Resources Information Center

    Schweri, Juerg; Hartog, Joop; Wolter, Stefan C.

    2011-01-01

    We use a unique data set about the wage distribution that Swiss students expect for themselves ex ante, deriving parametric and non-parametric measures to capture expected wage risk. These wage risk measures are unfettered by heterogeneity which handicapped the use of actual market wage dispersion as risk measure in earlier studies. Students in…

  10. Thermal effects in high average power optical parametric amplifiers.

    PubMed

    Rothhardt, Jan; Demmler, Stefan; Hädrich, Steffen; Peschel, Thomas; Limpert, Jens; Tünnermann, Andreas

    2013-03-01

    Optical parametric amplifiers (OPAs) have the reputation of being average power scalable due to the instantaneous nature of the parametric process (zero quantum defect). This Letter reveals serious challenges originating from thermal load in the nonlinear crystal caused by absorption. We investigate these thermal effects in high average power OPAs based on beta barium borate. Absorption of both pump and idler waves is identified to contribute significantly to heating of the nonlinear crystal. A temperature increase of up to 148 K with respect to the environment is observed and mechanical tensile stress up to 40 MPa is found, indicating a high risk of crystal fracture under such conditions. By restricting the idler to a wavelength range far from absorption bands and removing the crystal coating we reduce the peak temperature and the resulting temperature gradient significantly. Guidelines for further power scaling of OPAs and other nonlinear devices are given.

  11. Thermal effects in high average power optical parametric amplifiers.

    PubMed

    Rothhardt, Jan; Demmler, Stefan; Hädrich, Steffen; Peschel, Thomas; Limpert, Jens; Tünnermann, Andreas

    2013-03-01

    Optical parametric amplifiers (OPAs) have the reputation of being average power scalable due to the instantaneous nature of the parametric process (zero quantum defect). This Letter reveals serious challenges originating from thermal load in the nonlinear crystal caused by absorption. We investigate these thermal effects in high average power OPAs based on beta barium borate. Absorption of both pump and idler waves is identified to contribute significantly to heating of the nonlinear crystal. A temperature increase of up to 148 K with respect to the environment is observed and mechanical tensile stress up to 40 MPa is found, indicating a high risk of crystal fracture under such conditions. By restricting the idler to a wavelength range far from absorption bands and removing the crystal coating we reduce the peak temperature and the resulting temperature gradient significantly. Guidelines for further power scaling of OPAs and other nonlinear devices are given. PMID:23455291

  12. Parametric analysis of ATT configurations.

    NASA Technical Reports Server (NTRS)

    Lange, R. H.

    1972-01-01

    This paper describes the results of a Lockheed parametric analysis of the performance, environmental factors, and economics of an advanced commercial transport envisioned for operation in the post-1985 time period. The design parameters investigated include cruise speeds from Mach 0.85 to Mach 1.0, passenger capacities from 200 to 500, ranges of 2800 to 5500 nautical miles, and noise level criteria. NASA high performance configurations and alternate configurations are operated over domestic and international route structures. Indirect and direct costs and return on investment are determined for approximately 40 candidate aircraft configurations. The candidate configurations are input to an aircraft sizing and performance program which includes a subroutine for noise criteria. Comparisons are made between preferred configurations on the basis of maximum return on investment as a function of payload, range, and design cruise speed.

  13. Why preferring parametric forecasting to nonparametric methods?

    PubMed

    Jabot, Franck

    2015-05-01

    A recent series of papers by Charles T. Perretti and collaborators have shown that nonparametric forecasting methods can outperform parametric methods in noisy nonlinear systems. Such a situation can arise because of two main reasons: the instability of parametric inference procedures in chaotic systems which can lead to biased parameter estimates, and the discrepancy between the real system dynamics and the modeled one, a problem that Perretti and collaborators call "the true model myth". Should ecologists go on using the demanding parametric machinery when trying to forecast the dynamics of complex ecosystems? Or should they rely on the elegant nonparametric approach that appears so promising? It will be here argued that ecological forecasting based on parametric models presents two key comparative advantages over nonparametric approaches. First, the likelihood of parametric forecasting failure can be diagnosed thanks to simple Bayesian model checking procedures. Second, when parametric forecasting is diagnosed to be reliable, forecasting uncertainty can be estimated on virtual data generated with the fitted to data parametric model. In contrast, nonparametric techniques provide forecasts with unknown reliability. This argumentation is illustrated with the simple theta-logistic model that was previously used by Perretti and collaborators to make their point. It should convince ecologists to stick to standard parametric approaches, until methods have been developed to assess the reliability of nonparametric forecasting.

  14. Evidence of clinical competence.

    PubMed

    Lejonqvist, Gun-Britt; Eriksson, Katie; Meretoja, Riitta

    2012-06-01

    This cross-sectional research used a qualitative questionnaire to explore clinical competence in nursing. The aim was to look for evidence of how clinical competence showed itself in practice. In the research, the views from both education and working life are combined to broadly explore and describe clinical competence from the perspective of students, clinical preceptors and teachers. The questions were formulated on how clinical competence is characterised and experienced, what contributes to it and how it is maintained, and on the relation between clinical competence and evidence-based care. The answers were analysed by inductive content analysis. The results showed that clinical competence in practice is encountering, knowing, performing, maturing and improving. Clinical competence is an ongoing process, rather than a state and manifests itself in an ontological and a contextual dimension.

  15. Improvement of Statistical Decisions under Parametric Uncertainty

    NASA Astrophysics Data System (ADS)

    Nechval, Nicholas A.; Nechval, Konstantin N.; Purgailis, Maris; Berzins, Gundars; Rozevskis, Uldis

    2011-10-01

    A large number of problems in production planning and scheduling, location, transportation, finance, and engineering design require that decisions be made in the presence of uncertainty. Decision-making under uncertainty is a central problem in statistical inference, and has been formally studied in virtually all approaches to inference. The aim of the present paper is to show how the invariant embedding technique, the idea of which belongs to the authors, may be employed in the particular case of finding the improved statistical decisions under parametric uncertainty. This technique represents a simple and computationally attractive statistical method based on the constructive use of the invariance principle in mathematical statistics. Unlike the Bayesian approach, an invariant embedding technique is independent of the choice of priors. It allows one to eliminate unknown parameters from the problem and to find the best invariant decision rule, which has smaller risk than any of the well-known decision rules. To illustrate the proposed technique, application examples are given.

  16. Selected Parametric Effects on Materials Flammability Limits

    NASA Technical Reports Server (NTRS)

    Hirsch, David B.; Juarez, Alfredo; Peyton, Gary J.; Harper, Susana A.; Olson, Sandra L.

    2011-01-01

    NASA-STD-(I)-6001B Test 1 is currently used to evaluate the flammability of materials intended for use in habitable environments of U.S. spacecraft. The method is a pass/fail upward flame propagation test conducted in the worst case configuration, which is defined as a combination of a material s thickness, test pressure, oxygen concentration, and temperature that make the material most flammable. Although simple parametric effects may be intuitive (such as increasing oxygen concentrations resulting in increased flammability), combinations of multi-parameter effects could be more complex. In addition, there are a variety of material configurations used in spacecraft. Such configurations could include, for example, exposed free edges where fire propagation may be different when compared to configurations commonly employed in standard testing. Studies involving combined oxygen concentration, pressure, and temperature on flammability limits have been conducted and are summarized in this paper. Additional effects on flammability limits of a material s thickness, mode of ignition, burn-length criteria, and exposed edges are presented. The information obtained will allow proper selection of ground flammability test conditions, support further studies comparing flammability in 1-g with microgravity and reduced gravity environments, and contribute to persuasive scientific cases for rigorous space system fire risk assessments.

  17. Characteristics of stereo reproduction with parametric loudspeakers

    NASA Astrophysics Data System (ADS)

    Aoki, Shigeaki; Toba, Masayoshi; Tsujita, Norihisa

    2012-05-01

    A parametric loudspeaker utilizes nonlinearity of a medium and is known as a super-directivity loudspeaker. The parametric loudspeaker is one of the prominent applications of nonlinear ultrasonics. So far, the applications have been limited monaural reproduction sound system for public address in museum, station and street etc. In this paper, we discussed characteristics of stereo reproduction with two parametric loudspeakers by comparing with those with two ordinary dynamic loudspeakers. In subjective tests, three typical listening positions were selected to investigate the possibility of correct sound localization in a wide listening area. The binaural information was ILD (Interaural Level Difference) or ITD (Interaural Time Delay). The parametric loudspeaker was an equilateral hexagon. The inner and outer diameters were 99 and 112 mm, respectively. Signals were 500 Hz, 1 kHz, 2 kHz and 4 kHz pure tones and pink noise. Three young males listened to test signals 10 times in each listening condition. Subjective test results showed that listeners at the three typical listening positions perceived correct sound localization of all signals using the parametric loudspeakers. It was almost similar to those using the ordinary dynamic loudspeakers, however, except for the case of sinusoidal waves with ITD. It was determined the parametric loudspeaker could exclude the contradiction between the binaural information ILD and ITD that occurred in stereo reproduction with ordinary dynamic loudspeakers because the super directivity of parametric loudspeaker suppressed the cross talk components.

  18. Ionization Cooling using Parametric Resonances

    SciTech Connect

    Johnson, Rolland P.

    2008-06-07

    Ionization Cooling using Parametric Resonances was an SBIR project begun in July 2004 and ended in January 2008 with Muons, Inc., (Dr. Rolland Johnson, PI), and Thomas Jefferson National Accelerator Facility (JLab) (Dr. Yaroslav Derbenev, Subcontract PI). The project was to develop the theory and simulations of Parametric-resonance Ionization Cooling (PIC) so that it could be used to provide the extra transverse cooling needed for muon colliders in order to relax the requirements on the proton driver, reduce the site boundary radiation, and provide a better environment for experiments. During the course of the project, the theoretical understanding of PIC was developed and a final exposition is ready for publication. Workshops were sponsored by Muons, Inc. in May and September of 2007 that were devoted to the PIC technique. One outcome of the workshops was the interesting and somewhat unexpected realization that the beam emittances using the PIC technique can get small enough that space charge forces can be important. A parallel effort to develop our G4beamline simulation program to include space charge effects was initiated to address this problem. A method of compensating for chromatic aberrations by employing synchrotron motion was developed and simulated. A method of compensating for spherical aberrations using beamline symmetry was also developed and simulated. Different optics designs have been developed using the OptiM program in preparation for applying our G4beamline simulation program, which contains all the power of the Geant4 toolkit. However, no PIC channel design that has been developed has had the desired cooling performance when subjected to the complete G4beamline simulation program. This is believed to be the consequence of the difficulties of correcting the aberrations associated with the naturally large beam angles and beam sizes of the PIC method that are exacerbated by the fringe fields of the rather complicated channel designs that have been

  19. Self-seeding ring optical parametric oscillator

    DOEpatents

    Smith, Arlee V.; Armstrong, Darrell J.

    2005-12-27

    An optical parametric oscillator apparatus utilizing self-seeding with an external nanosecond-duration pump source to generate a seed pulse resulting in increased conversion efficiency. An optical parametric oscillator with a ring configuration are combined with a pump that injection seeds the optical parametric oscillator with a nanosecond duration, mJ pulse in the reverse direction as the main pulse. A retroreflecting means outside the cavity injects the seed pulse back into the cavity in the direction of the main pulse to seed the main pulse, resulting in higher conversion efficiency.

  20. Optimal Parametric Feedback Excitation of Nonlinear Oscillators

    NASA Astrophysics Data System (ADS)

    Braun, David J.

    2016-01-01

    An optimal parametric feedback excitation principle is sought, found, and investigated. The principle is shown to provide an adaptive resonance condition that enables unprecedentedly robust movement generation in a large class of oscillatory dynamical systems. Experimental demonstration of the theory is provided by a nonlinear electronic circuit that realizes self-adaptive parametric excitation without model information, signal processing, and control computation. The observed behavior dramatically differs from the one achievable using classical parametric modulation, which is fundamentally limited by uncertainties in model information and nonlinear effects inevitably present in real world applications.

  1. Optimal Parametric Feedback Excitation of Nonlinear Oscillators.

    PubMed

    Braun, David J

    2016-01-29

    An optimal parametric feedback excitation principle is sought, found, and investigated. The principle is shown to provide an adaptive resonance condition that enables unprecedentedly robust movement generation in a large class of oscillatory dynamical systems. Experimental demonstration of the theory is provided by a nonlinear electronic circuit that realizes self-adaptive parametric excitation without model information, signal processing, and control computation. The observed behavior dramatically differs from the one achievable using classical parametric modulation, which is fundamentally limited by uncertainties in model information and nonlinear effects inevitably present in real world applications. PMID:26871336

  2. Qualitative risk assessment for the endemisation of Dirofilaria repens in the state of Brandenburg (Germany) based on temperature-dependent vector competence.

    PubMed

    Sassnau, R; Genchi, C

    2013-07-01

    Climate change with an increase in average temperature may be responsible for propagation of temperature-dependent vectors and/or vector-associated pathogens in regions that were previously not endemic. The analysis of climate data of Brandenburg state (Germany) had showed that the extrinsic development of Dirofilaria repens, the causative agent of canine subcutaneous dirofilariosis, was possible from the years 2001 to 2012. This finding, associated to the movement of infected dogs and their relocation from endemic European areas to Germany makes possible a rapid endemization of the infection and highlight the risk for human health, being D. repens a frequent cause of zoonotic infections.

  3. Airy beam optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Aadhi, A.; Chaitanya, N. Apurv; Jabir, M. V.; Vaity, Pravin; Singh, R. P.; Samanta, G. K.

    2016-05-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51–1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).

  4. Airy beam optical parametric oscillator.

    PubMed

    Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K

    2016-01-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond). PMID:27143582

  5. Airy beam optical parametric oscillator.

    PubMed

    Aadhi, A; Chaitanya, N Apurv; Jabir, M V; Vaity, Pravin; Singh, R P; Samanta, G K

    2016-05-04

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51-1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond).

  6. Airy beam optical parametric oscillator

    PubMed Central

    Aadhi, A.; Chaitanya, N. Apurv; Jabir, M. V.; Vaity, Pravin; Singh, R. P.; Samanta, G. K.

    2016-01-01

    Airy beam, a non-diffracting waveform, has peculiar properties of self-healing and self-acceleration. Due to such unique properties, the Airy beam finds many applications including curved plasma wave-guiding, micro-particle manipulation, optically mediated particle clearing, long distance communication, and nonlinear frequency conversion. However, many of these applications including laser machining of curved structures, generation of curved plasma channels, guiding of electric discharges in a curved path, study of nonlinear propagation dynamics, and nonlinear interaction demand Airy beam with high power, energy, and wavelength tunability. Till date, none of the Airy beam sources have all these features in a single device. Here, we report a new class of coherent sources based on cubic phase modulation of a singly-resonant optical parametric oscillator (OPO), producing high-power, continuous-wave (cw), tunable radiation in 2-D Airy intensity profile existing over a length >2 m. Based on a MgO-doped periodically poled LiNbO3 crystal pumped at 1064 nm, the Airy beam OPO produces output power more than 8 W, and wavelength tunability across 1.51–1.97 μm. This demonstration gives new direction for the development of sources of arbitrary structured beams at any wavelength, power, and energy in all time scales (cw to femtosecond). PMID:27143582

  7. The Effect of GVHD on Long-term Outcomes after Peripheral Blood Allogeneic Stem Cell Transplantation from an HLA-identical Sibling in Adult Acute Lymphocytic Leukemia: A Landmark Analysis Approach in Competing Risks.

    PubMed

    Jalali, Arash; Alimoghaddam, Kamran; Mahmoudi, Mahmood; Mohammad, Kazem; Mousavi, Seied Asadollah; Bahar, Babak; Vaezi, Mohammad; Zeraati, Hojjat; Jahani, Mohammad; Ghavamzadeh, Ardeshir

    2014-01-01

    Allogeneic Hematopoietic stem cell transplantation (HSCT) is the most effective therapy to prevent relapse in acute lymphocytic leukemia (ALL). This benefit is affected by non-relapse mortality (NRM) due to complications such as graft versus host disease (GVHD). A new approach in analyzing time-dependent covariates in competing risks is landmark analysis. So, the aim of this study is to evaluate the effect of acute and chronic GVHD on long-term outcomes, relapse and NRM, after allogeneic HSCT in adult ALL using landmark analysis. This study was conducted on 252 ALL patients who were allogeneic transplanted from an HLA-identical sibling with peripheral blood (PB) as the source of stem cell from 2004 to 2012 and were followed-up until 2013. In the first 100 days after transplant, a landmark analysis on days +10, +11, +12, +17, +24, and +31 was applied to assess the effect of acute GVHD on early relapse and NRM. Similarly, for patients alive and event-free at day +100 after transplant, a landmark analysis at time points day +101, months +4, +5, +6, +9, and +12 was applied to evaluate the effect of chronic GVHD on late relapse and NRM. Five-year LFS and OS were 35.0% (95% CI: 29.1, 42.2%) and 37.5% (95% CI: 31.3, 45.0%), respectively. Five-year cumulative incidence of relapse was 44.5% (95% CI: 37.9, 51.0%) while this was 20.4% (95% CI: 15.4, 26.0%) for NRM. The landmark analysis in the first 100 days after transplant showed that the grade III/IV of aGVHD has a lower risk of relapse but higher risk of NRM after adjustment for the EBMT risk score. For patients alive at day +100, cGVHD had no significant effect on relapse. Limited cGVHD had lower risk of NRM and after 6 month post-transplant the risk of NRM decreased and there were not important difference between the groups of cGVHD. Using advanced models enables us to estimate the effects more precisely and ultimately make inference more accurately.

  8. Risk

    NASA Technical Reports Server (NTRS)

    Barshi, Immanuel

    2016-01-01

    Speaking up, i.e. expressing ones concerns, is a critical piece of effective communication. Yet, we see many situations in which crew members have concerns and still remain silent. Why would that be the case? And how can we assess the risks of speaking up vs. the risks of keeping silent? And once we do make up our minds to speak up, how should we go about it? Our workshop aims to answer these questions, and to provide us all with practical tools for effective risk assessment and effective speaking-up strategies..

  9. A uniform parametrization of moment tensors

    NASA Astrophysics Data System (ADS)

    Tape, Walter; Tape, Carl

    2015-09-01

    A moment tensor is a 3 × 3 symmetric matrix that expresses an earthquake source. We construct a parametrization of the 5-D space of all moment tensors of unit norm. The coordinates associated with the parametrization are closely related to moment tensor orientations and source types. The parametrization is uniform, in the sense that equal volumes in the coordinate domain of the parametrization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favour double couples.

  10. Parametrically disciplined operation of a vibratory gyroscope

    NASA Technical Reports Server (NTRS)

    Shcheglov, Kirill V. (Inventor); Hayworth, Ken J. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2008-01-01

    Parametrically disciplined operation of a symmetric nearly degenerate mode vibratory gyroscope is disclosed. A parametrically-disciplined inertial wave gyroscope having a natural oscillation frequency in the neighborhood of a sub-harmonic of an external stable clock reference is produced by driving an electrostatic bias electrode at approximately twice this sub-harmonic frequency to achieve disciplined frequency and phase operation of the resonator. A nearly symmetric parametrically-disciplined inertial wave gyroscope that can oscillate in any transverse direction and has more than one bias electrostatic electrode that can be independently driven at twice its oscillation frequency at an amplitude and phase that disciplines its damping to zero in any vibration direction. In addition, operation of a parametrically-disciplined inertial wave gyroscope is taught in which the precession rate of the driven vibration pattern is digitally disciplined to a prescribed non-zero reference value.

  11. Parametric models for samples of random functions

    SciTech Connect

    Grigoriu, M.

    2015-09-15

    A new class of parametric models, referred to as sample parametric models, is developed for random elements that match sample rather than the first two moments and/or other global properties of these elements. The models can be used to characterize, e.g., material properties at small scale in which case their samples represent microstructures of material specimens selected at random from a population. The samples of the proposed models are elements of finite-dimensional vector spaces spanned by samples, eigenfunctions of Karhunen–Loève (KL) representations, or modes of singular value decompositions (SVDs). The implementation of sample parametric models requires knowledge of the probability laws of target random elements. Numerical examples including stochastic processes and random fields are used to demonstrate the construction of sample parametric models, assess their accuracy, and illustrate how these models can be used to solve efficiently stochastic equations.

  12. Parametric instabilities in weakly magnetized plasma

    SciTech Connect

    Weatherall, J.C.; Goldman, M.V.; Nicholson, D.R.

    1981-05-15

    Parametric instabilities in a weakly magnetized plasma are discussed. The results are applied to waves excited by electron streams which travel outward from the Sun along solar-wind magnetic field lines, as in a type III solar radio burst.

  13. The Importance of Military Cultural Competence.

    PubMed

    Meyer, Eric G; Writer, Brian W; Brim, William

    2016-03-01

    Military cultural competence has recently gained national attention. Experts have posited that limited outcomes in the treatment of posttraumatic stress disorder and depression in the military may be related to limited familiarity with the military. National surveys have indicated low military cultural competence among providers and limited educational efforts on military culture or pertinent military pathology in medical schools and residency training programs. Military families, with their own unique military cultural identity, have been identified as a population with increased risks associated with deployment. In response to these findings, several curricula regarding military culture have been established and widely distributed. Assessments of military cultural competence have also been developed. The clinical impact of enhanced cultural competence in general has thus far been limited. The military, however, with its highly prescribed cultural identity, may be a model culture for further study. PMID:26830884

  14. The Importance of Military Cultural Competence.

    PubMed

    Meyer, Eric G; Writer, Brian W; Brim, William

    2016-03-01

    Military cultural competence has recently gained national attention. Experts have posited that limited outcomes in the treatment of posttraumatic stress disorder and depression in the military may be related to limited familiarity with the military. National surveys have indicated low military cultural competence among providers and limited educational efforts on military culture or pertinent military pathology in medical schools and residency training programs. Military families, with their own unique military cultural identity, have been identified as a population with increased risks associated with deployment. In response to these findings, several curricula regarding military culture have been established and widely distributed. Assessments of military cultural competence have also been developed. The clinical impact of enhanced cultural competence in general has thus far been limited. The military, however, with its highly prescribed cultural identity, may be a model culture for further study.

  15. Observation of Parametric Instability in Advanced LIGO.

    PubMed

    Evans, Matthew; Gras, Slawek; Fritschel, Peter; Miller, John; Barsotti, Lisa; Martynov, Denis; Brooks, Aidan; Coyne, Dennis; Abbott, Rich; Adhikari, Rana X; Arai, Koji; Bork, Rolf; Kells, Bill; Rollins, Jameson; Smith-Lefebvre, Nicolas; Vajente, Gabriele; Yamamoto, Hiroaki; Adams, Carl; Aston, Stuart; Betzweiser, Joseph; Frolov, Valera; Mullavey, Adam; Pele, Arnaud; Romie, Janeen; Thomas, Michael; Thorne, Keith; Dwyer, Sheila; Izumi, Kiwamu; Kawabe, Keita; Sigg, Daniel; Derosa, Ryan; Effler, Anamaria; Kokeyama, Keiko; Ballmer, Stefan; Massinger, Thomas J; Staley, Alexa; Heinze, Matthew; Mueller, Chris; Grote, Hartmut; Ward, Robert; King, Eleanor; Blair, David; Ju, Li; Zhao, Chunnong

    2015-04-24

    Parametric instabilities have long been studied as a potentially limiting effect in high-power interferometric gravitational wave detectors. Until now, however, these instabilities have never been observed in a kilometer-scale interferometer. In this Letter, we describe the first observation of parametric instability in a gravitational wave detector, and the means by which it has been removed as a barrier to progress. PMID:25955042

  16. Chaos control of parametric driven Duffing oscillators

    SciTech Connect

    Jin, Leisheng; Mei, Jie; Li, Lijie

    2014-03-31

    Duffing resonators are typical dynamic systems, which can exhibit chaotic oscillations, subject to certain driving conditions. Chaotic oscillations of resonating systems with negative and positive spring constants are identified to investigate in this paper. Parametric driver imposed on these two systems affects nonlinear behaviours, which has been theoretically analyzed with regard to variation of driving parameters (frequency, amplitude). Systematic calculations have been performed for these two systems driven by parametric pumps to unveil the controllability of chaos.

  17. A Hamiltonian approach to the parametric excitation

    NASA Astrophysics Data System (ADS)

    Leroy, V.; Bacri, J.-C.; Hocquet, T.; Devaud, M.

    2006-05-01

    We propose a solution of the parametrically excited oscillator problem using the Hamiltonian formalism introduced by Glauber. The main advantage is that, within the framework of this formalism, the different possible approximations appear much more naturally than in the standard textbook presentation. Experiments on adiabatic and resonant parametric excitations of a pendulum are presented as an illustration, with particular attention being paid to the role played by the phase of the excitation.

  18. Curriculum Competencies, 1984.

    ERIC Educational Resources Information Center

    Delaware Technical and Community Coll., Dover. Terry Campus.

    This manual specifies the skills and abilities possessed by the graduates of programs offered by the Terry Campus of Delaware Technical and Community College. First, introductory material discusses the college's competency-based philosophy and the efforts by faculty and administrators to criterion reference the competencies perceived by faculty to…

  19. Profiles of Algebraic Competence

    ERIC Educational Resources Information Center

    Humberstone, J.; Reeve, R.A.

    2008-01-01

    The algebraic competence of 72 12-year-old female students was examined to identify profiles of understanding reflecting different algebraic knowledge states. Beginning algebraic competence (mapping abilities: word-to-symbol and vice versa, classifying, and solving equations) was assessed. One week later, the nature of assistance required to map…

  20. Drafting. Competency Based Curriculum.

    ERIC Educational Resources Information Center

    Everly, Al; And Others

    This competency based drafting curriculum is presented in seven specialization sections with units in each section containing a competency statement, performance objective, learning activities, evaluation, and quiz or problem sheets. Some units also contain answer sheets and/or handout sheets. Sections and number of units presented are (1) basic…

  1. Adult Educators' Core Competences

    ERIC Educational Resources Information Center

    Wahlgren, Bjarne

    2016-01-01

    Which competences do professional adult educators need? This research note discusses the topic from a comparative perspective, finding that adult educators' required competences are wide-ranging, heterogeneous and complex. They are subject to context in terms of national and cultural environment as well as the kind of adult education concerned…

  2. Global Managers' Career Competencies

    ERIC Educational Resources Information Center

    Cappellen, Tineke; Janssens, Maddy

    2008-01-01

    Purpose: This study aims to empirically examine the career competencies of global managers having world-wide coordination responsibility: knowing-why, knowing-how and knowing-whom career competencies. Design/methodology/approach: Based on in-depth interviews with 45 global managers, the paper analyzes career stories from a content analysis…

  3. Competence, Curriculum, and Control.

    ERIC Educational Resources Information Center

    Jackson, Nancy S.

    1988-01-01

    Draws upon a case study of a community college program review to examine the application of a competency-based approach to the process of curriculum design. Suggests that competency-based curriculum development shifts the basis for decision making from teacher knowledge to an objectified accounting system of employers and curriculum technicians.…

  4. Competencies and Their Assessment

    ERIC Educational Resources Information Center

    Drisko, James W.

    2014-01-01

    This article explores competencies and methods for their assessment in higher education and in social work's accreditation standards. Many contemporary policy and educational accreditation efforts employ the model of competency assessment. The current emphasis on accountability in higher education, including the Council on Social Work…

  5. Assessing and Teaching Competence

    ERIC Educational Resources Information Center

    Grant, Terri

    2004-01-01

    The Professional Communication Unit (PCU) at the University of Cape Town (UCT) recently conducted a business communication needs analysis to determine student perceptions of their communicative competence and the teaching strategies being used to develop such competence. Students felt that the specialist, stand-alone communication program was more…

  6. Analyzing ADN competencies.

    PubMed

    Mitchell, P R

    1989-01-01

    El Paso Community College District, using the DACUM Process, identified 19 major competency areas with 313 specific competencies for AD Nursing. This article provides an overview of the DACUM Process, a discussion of the application to the ADN program, a summary of the results, and future activities.

  7. Developing Competence at Work

    ERIC Educational Resources Information Center

    Bound, Helen; Lin, Magdalene

    2013-01-01

    In this paper, we explore the relationship between differing conceptualisations of competence, and the implications of these differences for the enacted workplace curriculum and its pedagogical epistemologies. We argue that when competence is understood as a set of stand-alone attributes that reside within an individual, it limits and over…

  8. The Spiritual Competency Scale

    ERIC Educational Resources Information Center

    Robertson, Linda A.

    2010-01-01

    This study describes the development of the Spiritual Competency Scale, which was based on the Association for Spiritual, Ethical and Religious Values in Counseling's original Spiritual Competencies. Participants were 662 counseling students from religiously based and secular universities nationwide. Exploratory factor analysis revealed a 22-item,…

  9. Cultural Competence Revisited

    ERIC Educational Resources Information Center

    Garran, Ann Marie; Werkmeister Rozas, Lisa

    2013-01-01

    In 2001, the National Association of Social Workers (NASW) adopted 10 discrete standards of culturally competent practice which undergird our commitment to diversity and social justice. The concept of intersectionality is newly emerging in social work, though, causing us to reflect on our current conceptualizations of cultural competence.…

  10. Developing Culturally Competent Organizations.

    ERIC Educational Resources Information Center

    Focal Point, 1994

    1994-01-01

    This special issue examines multicultural aspects of services provided by agencies concerned with children's mental health. The lead article is titled "Developing Culturally Competent Organizations" by James L. Mason. This article uses the cultural competence model to discuss an organization's self-evaluation and its planning in the areas of…

  11. Competency and consent in dementia.

    PubMed

    Fellows, L K

    1998-07-01

    Health care for demented older persons presents a range of ethical dilemmas. The disease process affects cognitive abilities, making competency a central issue. The syndrome of dementia carries a complex social overlay that colors perceptions of these patients and of their capacity for making decisions. An argument is made for a coherent, ethically based decision-making process that can be applied across the whole spectrum of dementia severity. The major ethical principles implicated in assessing a patient's ability to consent to treatment are reviewed. A sliding scale model of capacity is presented, in which the patient's ability to decide is weighed against the risk associated with the treatment decision in question. This model preserves the autonomy of the demented patient while minimizing the potential for harm. In situations where the patient is deemed incapable, two approaches that can be applied to making treatment decisions are contrasted. The 'prior competent choice' standard stresses the values that the patient held while competent. The 'best interests' standard moves the focus to the patient's subjective experience at the time the treatment is considered. The relative merits of these two concepts are evaluated in the context of dementia. Surveys of actual decision-making practice are contrasted with ethical and legal principles. The challenges inherent to applying the best interests standard are discussed. Despite the pitfalls, this standard offers an opportunity to restore the demented patient's sense of self. PMID:9670887

  12. Competencies Framework for Climate Services.

    NASA Astrophysics Data System (ADS)

    Aguilar, Enric

    2016-04-01

    The World Climate Conference-3 (Geneva, 2009) established the Global Framework for Climate Services (GFCS) to enable better management of the risks of climate variability and change and adaptation to climate change at all levels, through development and incorporation of science-based climate information and prediction into planning, policy and practice. The GFCS defines Climate Services as the result of transforming climate data into climate information in a way that responds to user needs and assists decision-making by individuals and organizations. Capacity Development is a cross-cutting pillar of the GFCS to ensure that services are provided by institutions with professionals whom achieved the adequate set of competencies recommended by WMO, which are yet to be fully defined. The WMO-Commission for Climatology Expert Team on Education and Training, ET-ETR, has been working to define a Competencies Framework for Climate Services to help the institutions to deliver high quality climate services in compliance with WMO standards and regulations, specifically those defined by WMO's Commission for Climatology and the GFCS. This framework is based in 5 areas or competence, closely associated to the areas of work of climate services providers: create and manage climate data sets; derive products from climate data; create and/or interpret climate forecasts and model output; ensure the quality of climate information and services; communicate climatological information with users. With this contribution, we intend to introduce to a wider audience the rationale behind these 5 top-level competency statements and the performance criteria associated with them, as well as the plans of the ET-ETR for further developing them into an instrument to support education and training within the WMO members, specially the National Meteorological and Hydrological Services.

  13. Developing emergency nursing competence.

    PubMed

    Proehl, Jean A

    2002-03-01

    Developing and maintaining the competence emergency nurses need is an important function of emergency clinical nurse specialists (CNS), educators, and other members of the emergency department (ED) leadership team. A thorough orientation is the first and most important step in developing the competence of emergency nurses. After orientation, the challenge is to maintain currency of practice in the face of incessant change such as new medications, new equipment, and new therapies in emergency care. This article focuses on the orientation of emergency nurses. A related article in this issue addresses assessment of competency. PMID:11818264

  14. Grating lobe elimination in steerable parametric loudspeaker.

    PubMed

    Shi, Chuang; Gan, Woon-Seng

    2011-02-01

    In the past two decades, the majority of research on the parametric loudspeaker has concentrated on the nonlinear modeling of acoustic propagation and pre-processing techniques to reduce nonlinear distortion in sound reproduction. There are, however, very few studies on directivity control of the parametric loudspeaker. In this paper, we propose an equivalent circular Gaussian source array that approximates the directivity characteristics of the linear ultrasonic transducer array. By using this approximation, the directivity of the sound beam from the parametric loudspeaker can be predicted by the product directivity principle. New theoretical results, which are verified through measurements, are presented to show the effectiveness of the delay-and-sum beamsteering structure for the parametric loudspeaker. Unlike the conventional loudspeaker array, where the spacing between array elements must be less than half the wavelength to avoid spatial aliasing, the parametric loudspeaker can take advantage of grating lobe elimination to extend the spacing of ultrasonic transducer array to more than 1.5 wavelengths in a typical application.

  15. Parametric excitation of magnetization by electric field

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Jin; Lee, Han Kyu; Verba, Roman; Katine, Jordan; Tiberkevich, Vasil; Slavin, Andrei; Barsukov, Igor; Krivorotov, Ilya

    Manipulation of magnetization by electric field is of primary importance for development of low-power spintronic devices. We present the first experimental demonstration of parametric generation of magnetic oscillations by electric field. We realize the parametric generation in CoFeB/MgO/SAF nanoscale magnetic tunnel junctions (MTJs). The magnetization of the free layer is perpendicular to the sample plane while the magnetizations of the synthetic antiferromagnet (SAF) lie in the plane. We apply microwave voltage to the MTJ at 2 f, where f is the ferromagnetic resonance frequency of the free layer. In this configuration, the oscillations can only be driven parametrically via voltage-controlled magnetic anisotropy (VCMA) whereby electric field across the MgO barrier modulates the free layer anisotropy. The parametrically driven oscillations are detected via microwave voltage from the MTJ near f and show resonant character, observed only in a narrow range of drive frequencies near 2 f. The excitation also exhibits a well-pronounced threshold drive voltage of approximately 0.1 Volts. Our work demonstrates a low threshold for parametric excitation of magnetization by VCMA that holds promise for the development of energy-efficient nanoscale spin wave devices.

  16. Optimization of noncollinear optical parametric amplification

    NASA Astrophysics Data System (ADS)

    Schimpf, D. N.; Rothardt, J.; Limpert, J.; Tünnermann, A.

    2007-02-01

    Noncollinearly phase-matched optical parametric amplifiers (NOPAs) - pumped with the green light of a frequency doubled Yb-doped fiber-amplifier system 1, 2 - permit convenient generation of ultrashort pulses in the visible (VIS) and near infrared (NIR) 3. The broad bandwidth of the parametric gain via the noncollinear pump configuration allows amplification of few-cycle optical pulses when seeded with a spectrally flat, re-compressible signal. The short pulses tunable over a wide region in the visible permit transcend of frontiers in physics and lifescience. For instance, the resulting high temporal resolution is of significance for many spectroscopic techniques. Furthermore, the high magnitudes of the peak-powers of the produced pulses allow research in high-field physics. To understand the demands of noncollinear optical parametric amplification using a fiber pump source, it is important to investigate this configuration in detail 4. An analysis provides not only insight into the parametric process but also determines an optimal choice of experimental parameters for the objective. Here, the intention is to design a configuration which yields the shortest possible temporal pulse. As a consequence of this analysis, the experimental setup could be optimized. A number of aspects of optical parametric amplifier performance have been treated analytically and computationally 5, but these do not fully cover the situation under consideration here.

  17. Parametric Mapping of Contrasted Ovarian Transvaginal Sonography

    PubMed Central

    Korhonen, Katrina; Moore, Ryan; Lyshchik, Andrej; Fleischer, Arthur C.

    2014-01-01

    The purpose of this study was to assess the accuracy of parametric analysis of transvaginal contrast-enhanced ultrasound (TV-CEUS) for distinguishing benign versus malignant ovarian masses. A total of 48 ovarian masses (37 benign and 11 borderline/malignant) were examined with TV-CEUS (Definity, Lantheus, North Bilreca, MA; Philips iU22, Bothell, WA). Parametric images were created offline with a quantification software (Bracco Suisse SA, Geneva, Switzerland) with map color scales adjusted such that abnormal hemodynamics were represented by the color red and the presence of any red color could be used to differentiate benign and malignant tumors. Using these map color scales, low values of the perfusion parameter were coded in blue, and intermediate values of the perfusion parameter were coded in yellow. Additionally, for each individual color (red, blue, or yellow), a darker shade of that color indicated a higher intensity value. Our study found that the parametric mapping method was considerably more sensitive than standard ROI analysis for the detection of malignant tumors but was also less specific than standard ROI analysis. Parametric mapping allows for stricter cut-off criteria, as hemodynamics are visualized on a finer scale than ROI analyses, and as such, parametric maps are a useful addition to TV-CEUS analysis by allowing ROIs to be limited to areas of highest malignant potential. PMID:26002525

  18. Transform-limited, narrow-linewidth, terahertz-wave parametric generator

    NASA Astrophysics Data System (ADS)

    Kawase, Kodo; Shikata, Jun-ichi; Imai, Kazuhiro; Ito, Hiromasa

    2001-05-01

    An injection-seeded nanosecond terahertz (THz) wave parametric generator was demonstrated using nonlinear crystals that were pumped by a single frequency Nd:yttrium-aluminum-garnet laser. Spectrum narrowing to the Fourier transform limit (ν=1.58 THz, Δν<200 MHz) was achieved by injection seeding the idler wave (near-infrared Stokes). This resulted in a THz-wave output power (900 pJ/pulse, >100 mW peak) approximately 300 times higher than that of a conventional THz-wave parametric generator, which has no injection seeder. This compact system operates at room temperature and promises to be a widely tunable THz-wave source that will compete with free-electron lasers and p-Ge lasers.

  19. Non-parametric partitioning of SAR images

    NASA Astrophysics Data System (ADS)

    Delyon, G.; Galland, F.; Réfrégier, Ph.

    2006-09-01

    We describe and analyse a generalization of a parametric segmentation technique adapted to Gamma distributed SAR images to a simple non parametric noise model. The partition is obtained by minimizing the stochastic complexity of a quantized version on Q levels of the SAR image and lead to a criterion without parameters to be tuned by the user. We analyse the reliability of the proposed approach on synthetic images. The quality of the obtained partition will be studied for different possible strategies. In particular, one will discuss the reliability of the proposed optimization procedure. Finally, we will precisely study the performance of the proposed approach in comparison with the statistical parametric technique adapted to Gamma noise. These studies will be led by analyzing the number of misclassified pixels, the standard Hausdorff distance and the number of estimated regions.

  20. Parametric instabilities in the LCGT arm cavity

    NASA Astrophysics Data System (ADS)

    Yamamoto, K.; Uchiyama, T.; Miyoki, S.; Ohashi, M.; Kuroda, K.; Numata, K.

    2008-07-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (USA). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta2O5) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  1. Parametric analysis of ATM solar array.

    NASA Technical Reports Server (NTRS)

    Singh, B. K.; Adkisson, W. B.

    1973-01-01

    The paper discusses the methods used for the calculation of ATM solar array performance characteristics and provides the parametric analysis of solar panels used in SKYLAB. To predict the solar array performance under conditions other than test conditions, a mathematical model has been developed. Four computer programs have been used to convert the solar simulator test data to the parametric curves. The first performs module summations, the second determines average solar cell characteristics which will cause a mathematical model to generate a curve matching the test data, the third is a polynomial fit program which determines the polynomial equations for the solar cell characteristics versus temperature, and the fourth program uses the polynomial coefficients generated by the polynomial curve fit program to generate the parametric data.

  2. Parametric instabilities in helicon-produced plasmas

    SciTech Connect

    Aliev, Yu.M.; Kraemer, M.

    2005-07-15

    Parametric instabilities arising in the pump field of a helicon wave are analyzed for typical parameters of helicon-produced plasmas. The pump wavenumber parallel to the magnetic field is assumed to be finite according to recent experimental findings obtained on a high-density helicon discharge. The parametric decay of the helicon pump wave into ion-sound and Trivelpiece-Gould waves is investigated. The approach takes into account that the damping rate of the Trivelpiece-Gould wave is generally much higher than the ion-sound frequency. The theoretical results are in agreement with the growth rates and thresholds of this instability, as well as the dispersion properties of the decay waves observed in helicon experiments. Estimates of the level of the decay parametric turbulence turn out to be sufficiently high to account for the strong absorption observed in helicon-produced plasmas.

  3. Parametric modelling of a knee joint prosthesis.

    PubMed

    Khoo, L P; Goh, J C; Chow, S L

    1993-01-01

    This paper presents an approach for the establishment of a parametric model of knee joint prosthesis. Four different sizes of a commercial prosthesis are used as an example in the study. A reverse engineering technique was employed to reconstruct the prosthesis on CATIA, a CAD (computer aided design) system. Parametric models were established as a result of the analysis. Using the parametric model established and the knee data obtained from a clinical study on 21 pairs of cadaveric Asian knees, the development of a prototype prosthesis that suits a patient with a very small knee joint is presented. However, it was found that modification to certain parameters may be inevitable due to the uniqueness of the Asian knee. An avenue for rapid modelling and eventually economical production of a customized knee joint prosthesis for patients is proposed and discussed.

  4. Modeling personnel turnover in the parametric organization

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.

    1991-01-01

    A model is developed for simulating the dynamics of a newly formed organization, credible during all phases of organizational development. The model development process is broken down into the activities of determining the tasks required for parametric cost analysis (PCA), determining the skills required for each PCA task, determining the skills available in the applicant marketplace, determining the structure of the model, implementing the model, and testing it. The model, parameterized by the likelihood of job function transition, has demonstrated by the capability to represent the transition of personnel across functional boundaries within a parametric organization using a linear dynamical system, and the ability to predict required staffing profiles to meet functional needs at the desired time. The model can be extended by revisions of the state and transition structure to provide refinements in functional definition for the parametric and extended organization.

  5. Parametric Amplification of Scattered Atom Pairs

    SciTech Connect

    Campbell, Gretchen K.; Mun, Jongchul; Boyd, Micah; Streed, Erik W.; Ketterle, Wolfgang; Pritchard, David E.

    2006-01-20

    We have observed parametric generation and amplification of ultracold atom pairs. A {sup 87}Rb Bose-Einstein condensate was loaded into a one-dimensional optical lattice with quasimomentum k{sub 0} and spontaneously scattered into two final states with quasimomenta k{sub 1} and k{sub 2}. Furthermore, when a seed of atoms was first created with quasimomentum k{sub 1} we observed parametric amplification of scattered atoms pairs in states k{sub 1} and k{sub 2} when the phase-matching condition was fulfilled. This process is analogous to optical parametric generation and amplification of photons and could be used to efficiently create entangled pairs of atoms. Furthermore, these results explain the dynamic instability of condensates in moving lattices observed in recent experiments.

  6. Parametric number covariance in quantum chaotic spectra.

    PubMed

    Vinayak; Kumar, Sandeep; Pandey, Akhilesh

    2016-03-01

    We study spectral parametric correlations in quantum chaotic systems and introduce the number covariance as a measure of such correlations. We derive analytic results for the classical random matrix ensembles using the binary correlation method and obtain compact expressions for the covariance. We illustrate the universality of this measure by presenting the spectral analysis of the quantum kicked rotors for the time-reversal invariant and time-reversal noninvariant cases. A local version of the parametric number variance introduced earlier is also investigated.

  7. Parametrically driven surface waves on viscous ferrofluids

    NASA Astrophysics Data System (ADS)

    Müller, Hanns Walter

    1998-11-01

    Standing waves on the surface of a ferrofluid in a normal magnetic field can be excited by a vertical vibration of the container. A stability theory for the onset of these parametrically driven waves is developed, taking viscous dissipation and finite depth effects into account. It will be shown that a careful choice of the filling level permits the normal and anomalous dispersion branches to be measured. Furthermore it will be demonstrated that the parametric driving mechanism may lead to a delay of the Rosensweig instability. A bicritical situation can be achieved when Rosensweig and Faraday waves interact.

  8. Parametric Amplification For Detecting Weak Optical Signals

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Chen, Chien; Chakravarthi, Prakash

    1996-01-01

    Optical-communication receivers of proposed type implement high-sensitivity scheme of optical parametric amplification followed by direct detection for reception of extremely weak signals. Incorporates both optical parametric amplification and direct detection into optimized design enhancing effective signal-to-noise ratios during reception in photon-starved (photon-counting) regime. Eliminates need for complexity of heterodyne detection scheme and partly overcomes limitations imposed on older direct-detection schemes by noise generated in receivers and by limits on quantum efficiencies of photodetectors.

  9. Parametric injection for monoenergetic electron acceleration

    NASA Astrophysics Data System (ADS)

    Oguchi, A.; Zhidkov, A.; Takano, K.; Hotta, E.; Nemoto, K.; Nakajima, K.

    2008-05-01

    Electrons are accelerated in the laser wakefield (LWFA). This mechanism has been studied by 2D or 3D Particle In Cell simulation. However, how the electrons are injected in the wakefield is not understood. In this paper, we consider about the process of self -injection and propose new scheme. When plasma electron density modulates, parametric resonance of electron momentum is induced. The parametric resonance depends on laser waist modulation. We carried out 2D PIC simulation with the initial condition decided from resonance condition. Moreover, we analyze experimental result that generated 200-250 MeV monoenergetic electron beam with 400TW intense laser in CAEP in China.

  10. Hamiltonian dynamics of the parametrized electromagnetic field

    NASA Astrophysics Data System (ADS)

    Barbero G, J. Fernando; Margalef-Bentabol, Juan; Villaseñor, Eduardo J. S.

    2016-06-01

    We study the Hamiltonian formulation for a parametrized electromagnetic field with the purpose of clarifying the interplay between parametrization and gauge symmetries. We use a geometric approach which is tailor-made for theories where embeddings are part of the dynamical variables. Our point of view is global and coordinate free. The most important result of the paper is the identification of sectors in the primary constraint submanifold in the phase space of the model where the number of independent components of the Hamiltonian vector fields that define the dynamics changes. This explains the non-trivial behavior of the system and some of its pathologies.

  11. Cosmetology. Ohio's Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This comprehensive and verified employer competency list was developed from a modified DACUM (Developing a Curriculum) process involving business, industry, labor, and community agency representatives from Ohio. This competency list contains 17 units (with or without subunits), competencies, and competency builders that identify the occupational,…

  12. Dental Assisting Competencies. Final Report.

    ERIC Educational Resources Information Center

    Richards, Beverly; And Others

    This document contains dental assisting competencies and competency-based performance objectives, learning activities, resources, and evaluation procedures for each competency that was adapted and developed by instructors of dental assisting to suit the needs and legal parameters of Pennsylvania. The competencies and associated elements are…

  13. Medical Assisting Competencies. Final Report.

    ERIC Educational Resources Information Center

    Richards, Beverly; And Others

    This document contains medical assisting competencies and competency-based performance objectives, learning activities, resources, and levels of achievement for each competency that were adapted and developed by instructors of medical assisting to suit the needs and legal parameters of Pennsylvania. The competencies and associated elements are…

  14. Welding. Ohio's Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Ohio Competency Analysis Profile (OCAP), derived from a modified Developing a Curriculum (DACUM) process, is a comprehensive and verified employer competency list for a welding program. It contains units (with or without subunits), competencies, and competency builders that identify the occupational, academic, and employability skills needed…

  15. Noise figure of hybrid optical parametric amplifiers.

    PubMed

    Marhic, Michel E

    2012-12-17

    Following a fiber optical parametric amplifier, used as a wavelength converter or in the phase-sensitive mode, by a phase-insensitive amplifier (PIA) can significantly reduce four-wave mixing between signals in broadband systems. We derive the quantum mechanical noise figures (NF) for these two hybrid configurations, and show that adding the PIA only leads to a moderate increase in NF.

  16. New Logic Circuit with DC Parametric Excitation

    NASA Astrophysics Data System (ADS)

    Sugahara, Masanori; Kaneda, Hisayoshi

    1982-12-01

    It is shown that dc parametric excitation is possible in a circuit named JUDO, which is composed of two resistively-connected Josephson junctions. Simulation study proves that the circuit has large gain and properties suitable for the construction of small, high-speed logic circuits.

  17. Parametric modelling for electrical impedance spectroscopy system.

    PubMed

    Lu, L; Hamzaoui, L; Brown, B H; Rigaud, B; Smallwood, R H; Barber, D C; Morucci, J P

    1996-03-01

    Three parametric modelling approaches based on the Cole-Cole model are introduced. Comparison between modelling only the real part and modelling both the real and imaginary parts is carried out by simulations, in which random and systematic noise are considered, respectively. The results of modelling the in vitro data collected from sheep are given to reach the conclusions.

  18. Measurement selection for parametric IC fault diagnosis

    NASA Technical Reports Server (NTRS)

    Wu, A.; Meador, J.

    1991-01-01

    Experimental results obtained with the use of measurement reduction for statistical IC fault diagnosis are described. The reduction method used involves data pre-processing in a fashion consistent with a specific definition of parametric faults. The effects of this preprocessing are examined.

  19. The Study of Stress and Competence in Children: A Building Block for Developmental Psychopathology.

    ERIC Educational Resources Information Center

    Garmezy, Norman; And Others

    1984-01-01

    Discusses building blocks for a developmental psychopathology, focusing on studies of risk, competence, and protective factors. Describes studies of stress and competence, giving particular attention to methodology and strategies for data analysis. A three-model approach to stress resistance is also presented, and Project Competence is evaluated…

  20. A novel SURE-based criterion for parametric PSF estimation.

    PubMed

    Xue, Feng; Blu, Thierry

    2015-02-01

    We propose an unbiased estimate of a filtered version of the mean squared error--the blur-SURE (Stein's unbiased risk estimate)--as a novel criterion for estimating an unknown point spread function (PSF) from the degraded image only. The PSF is obtained by minimizing this new objective functional over a family of Wiener processings. Based on this estimated blur kernel, we then perform nonblind deconvolution using our recently developed algorithm. The SURE-based framework is exemplified with a number of parametric PSF, involving a scaling factor that controls the blur size. A typical example of such parametrization is the Gaussian kernel. The experimental results demonstrate that minimizing the blur-SURE yields highly accurate estimates of the PSF parameters, which also result in a restoration quality that is very similar to the one obtained with the exact PSF, when plugged into our recent multi-Wiener SURE-LET deconvolution algorithm. The highly competitive results obtained outline the great potential of developing more powerful blind deconvolution algorithms based on SURE-like estimates.

  1. A novel SURE-based criterion for parametric PSF estimation.

    PubMed

    Xue, Feng; Blu, Thierry

    2015-02-01

    We propose an unbiased estimate of a filtered version of the mean squared error--the blur-SURE (Stein's unbiased risk estimate)--as a novel criterion for estimating an unknown point spread function (PSF) from the degraded image only. The PSF is obtained by minimizing this new objective functional over a family of Wiener processings. Based on this estimated blur kernel, we then perform nonblind deconvolution using our recently developed algorithm. The SURE-based framework is exemplified with a number of parametric PSF, involving a scaling factor that controls the blur size. A typical example of such parametrization is the Gaussian kernel. The experimental results demonstrate that minimizing the blur-SURE yields highly accurate estimates of the PSF parameters, which also result in a restoration quality that is very similar to the one obtained with the exact PSF, when plugged into our recent multi-Wiener SURE-LET deconvolution algorithm. The highly competitive results obtained outline the great potential of developing more powerful blind deconvolution algorithms based on SURE-like estimates. PMID:25531950

  2. Parametric acoustic arrays: A state of the art review

    NASA Technical Reports Server (NTRS)

    Fenlon, F. H.

    1976-01-01

    Following a brief introduction to the concept of parametric acoustic interactions, the basic properties of parametric transmitting and receiving arrays are considered in the light of conceptual advances resulting from experimental and theoretical investigations that have taken place since 1963.

  3. Simple parametrization of fragment reduced widths in heavy ion collisions.

    PubMed

    Tripathi, R K; Townsend, L W

    1994-04-01

    A systematic analysis of the observed reduced widths obtained in relativistic heavy ion fragmentation reactions is used to develop a phenomenological parametrization of these data. The parametrization is simple, accurate, and completely general in applicability.

  4. Pseudodementia and competency.

    PubMed

    Good, M I

    1993-01-01

    An increase in the number of challenges to competency determinations in probate cases parallels an increasingly aging population. In the literature on competency determination, there is little if any discussion of the implications of pseudodementing conditions, which can quite readily be misdiagnosed as true dementias, especially in the elderly. This case report describes a patient thought to have had a stroke with dementia and paresis who turned out to have had a pseudodementia. She later made a dramatic and somewhat surprising recovery. It subsequently came to light that a nearly successful attempt had been made to defraud her of her estate during her presumed dementia, which was thought to have been irreversible. The case underscores issues in competency determination, including matters of diagnosis, prognosis, and undue influence.

  5. Meta-Analysis of Candidate Gene Effects Using Bayesian Parametric and Non-Parametric Approaches

    PubMed Central

    Wu, Xiao-Lin; Gianola, Daniel; Rosa, Guilherme J. M.; Weigel, Kent A.

    2014-01-01

    Candidate gene (CG) approaches provide a strategy for identification and characterization of major genes underlying complex phenotypes such as production traits and susceptibility to diseases, but the conclusions tend to be inconsistent across individual studies. Meta-analysis approaches can deal with these situations, e.g., by pooling effect-size estimates or combining P values from multiple studies. In this paper, we evaluated the performance of two types of statistical models, parametric and non-parametric, for meta-analysis of CG effects using simulated data. Both models estimated a “central” effect size while taking into account heterogeneity over individual studies. The empirical distribution of study-specific CG effects was multi-modal. The parametric model assumed a normal distribution for the study-specific CG effects whereas the non-parametric model relaxed this assumption by posing a more general distribution with a Dirichlet process prior (DPP). Results indicated that the meta-analysis approaches could reduce false positive or false negative rates by pooling strengths from multiple studies, as compared to individual studies. In addition, the non-parametric, DPP model captured the variation of the “data” better than its parametric counterpart. PMID:25057320

  6. Forensic psychiatric examinations: competency.

    PubMed

    Koson, D F

    1982-01-01

    The many definitions of competency in civil, criminal, and domestic relations law are discussed with emphasis on the various legal criteria for competency and the different classes of psychiatric information required to apply the criteria to a given case. Within the context of a general discussion of forensic examinations, techniques for gathering the right kind of information are systematically related to the exigencies of evaluating past, present, or future mental states by selectively altering the focus of mental status evaluations and history-taking. In addition, special investigative techniques such as hypnosis, Amytal sodium interview, stress interview, psychological testing, and others are discussed.

  7. Single-mode approximation of parametric down-conversion

    SciTech Connect

    Li Yongmin; Mikami, Hideharu; Wang Haibo; Kobayashi, Takayoshi

    2005-12-15

    In this paper, we study the theory of spontaneous parametric down-conversion pumped by a short coherent pulse. It is shown that when single spatial mode filters and narrow band optical filters are used to filter the output state of parametric down-conversion, the postselected state of parametric down-conversion can be approximately described by a simple single-mode theory.

  8. Competencies in Teaching English.

    ERIC Educational Resources Information Center

    Purves, Alan C.

    This paper discusses suggested requirements for a competency-based English teacher training program on the high school or college level. The author argues that an English teacher needs to demonstrate a basic knowledge of the subject matter in three areas: the structure and history of the English language, rhetorical theory and practice, and…

  9. Competency Development for Principals.

    ERIC Educational Resources Information Center

    Snyder, Karolyn J.

    This paper describes two conceptual models for addressing long-range development needs of principals. The first, a job competency model for managing productive schools, presents a comprehensive view of the central job tasks of the principal for stretching the school's capacity to influence achievement norms. Changing the school's work norms…

  10. Competencies in the Heartland

    ERIC Educational Resources Information Center

    Cejda, Brent

    2012-01-01

    Although many of the issues facing community colleges are similar, rural community colleges face additional leadership challenges due to limited resources, geographic isolation, and static economies. This chapter focuses on the impact of location on the interpretation and development of the leadership competencies. The chapter concludes with…

  11. What Are Humanistic Competencies?

    ERIC Educational Resources Information Center

    Sauter, Donald L.

    1976-01-01

    This article is not an attempt to outline the training program for developing humanistic competencies nor is it intended to list those immeasurable words that have been used so much in the past such as caring, genuineness, loving and others, but merely to point out that there are models from which observable changes can take place. (Author/RK)

  12. Pragmatics and Communicative Competences

    ERIC Educational Resources Information Center

    Lin, Grace Hui Chin; Su, Simon Chun Feng; Ho, Max Ming Hsuang

    2009-01-01

    Pragmatics is included in one of four communicative competences (Canale, 1980). It is necessary and important to teach pragmatics at school in our globalized world in order to avoid as much as misunderstanding, which is likely to stem from cultural difference. As a result, greater importance should be attached to diverse customs and pragmatics.…

  13. Competency in the Cockpit.

    ERIC Educational Resources Information Center

    Brown, H. M.

    1992-01-01

    Examines how modern technology is redefining competences, particularly those required by aircrews in state-of-the-art cockpits and how rule-based descriptions may not always be as practical as cognitive schemas and frames or case-based reasoning. Concludes that a wider systems perspective must include a balance between intuitive and analytic…

  14. Teach to Compete

    ERIC Educational Resources Information Center

    Shields, David Light; Funk, Christopher

    2011-01-01

    After years of working with athletes and coaches of all ages, the authors have come to the conclusion that young people need to be taught how to compete. Rather than assume students understand competition, it is vital that they are educated about it. Coaches and physical educators have both a unique opportunity and profound responsibility to teach…

  15. Intellectual Competence and Aggression.

    ERIC Educational Resources Information Center

    Huesmann, L. Rowell; Yarmel, Patty Warnick

    Using data from a broader longitudinal study, this investigation explores within-subject and cross-generational stability of intellectual competence and the relationship of such stability to aggressive behavior. Data were gathered three times (when subjects' modal age was 8, 19, and 30 years). Initially, subjects included the entire population…

  16. Diesel Vehicle Maintenance Competencies.

    ERIC Educational Resources Information Center

    Braswell, Robert; And Others

    Designed to provide a model set of competencies, this manual presents tasks which were identified by employers, employees, and teachers as important in a postsecondary diesel vehicle maintenance curriculum. The tasks are divided into seven major component areas of instruction: chassis and suspension, diesel engines, diesel fuel, electrical,…

  17. Ohio Biotechnology Competency Profile.

    ERIC Educational Resources Information Center

    Miller, Lavonna; Bowermeister, Bob; Boudreau, Joyce

    This document, which lists the biotechnology competencies identified by representatives from biotechnology businesses and industries as well as secondary and post-secondary educators throughout Ohio, is intended to assist individuals and organizations in developing college tech prep programs that will prepare students from secondary through…

  18. Adult educators' core competences

    NASA Astrophysics Data System (ADS)

    Wahlgren, Bjarne

    2016-06-01

    Which competences do professional adult educators need? This research note discusses the topic from a comparative perspective, finding that adult educators' required competences are wide-ranging, heterogeneous and complex. They are subject to context in terms of national and cultural environment as well as the kind of adult education concerned (e.g. basic education, work-related education etc.). However, it seems that it is possible to identify certain competence requirements which transcend national, cultural and functional boundaries. This research note summarises these common or "core" requirements, organising them into four thematic subcategories: (1) communicating subject knowledge; (2) taking students' prior learning into account; (3) supporting a learning environment; and (4) the adult educator's reflection on his or her own performance. At the end of his analysis of different competence profiles, the author notes that adult educators' ability to train adult learners in a way which then enables them to apply and use what they have learned in practice (thus performing knowledge transfer) still seems to be overlooked.

  19. Competence Enhancement Behavior Management

    ERIC Educational Resources Information Center

    Farmer, Thomas W.; Goforth, Jennifer B.; Hives, Jacqueline; Aaron, Annie; Jackson, Frances; Sgammato, Adrienne

    2006-01-01

    Competence Enhancement Behavior Management is presented as a framework for supporting students with challenging behaviors in general education classrooms. This approach emphasizes classroom management and discipline strategies that (a) help to build positive relations with students, (b) communicate to students that they are important, and (c)…

  20. Welding. Competencies for Articulation.

    ERIC Educational Resources Information Center

    Southeast Community Coll., Lincoln, NE.

    Materials contained in this guide present competencies describing welding skills necessary for success in initial employment or applicable to advanced educational placement, and may be used by administrators, students, and secondary and postsecondary vocational teachers. The student outcomes section provides guidelines for planning of and…

  1. Competence without Credentials.

    ERIC Educational Resources Information Center

    Stacey, Nevzer G., Ed.

    These workshop papers address the challenges of alternative credentials, new modes of instruction, and multiple sources of instruction. Following an introduction by Nevzer G. Stacey, "Competence without Credentials: Promise and Potential Problems of Computer-Based Distance Education" (Stephen R. Barley) provides a conceptual framework for the…

  2. Plastics Technical Competency Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document, which is intended to assist individuals responsible for developing tech prep programs, lists the occupational, academic, and employability competencies that representatives from education, business/industry, and labor throughout Ohio have identified as being necessary for employment in technician-level positions involving the…

  3. Entanglement of Coupled Optomechanical Systems Improved by Optical Parametric Amplifiers

    NASA Astrophysics Data System (ADS)

    Pan, Guixia; Xiao, Ruijie; Zhou, Ling

    2016-08-01

    A scheme to generate the stationary entanglement of two distant coupled optical cavities placed optical parametric amplifiers is proposed. We study how the optical parametric amplifiers can affect the entanglement behaviors of the movable mirrors and the cavity fields. With the existence of optical parametric amplifiers, we show that larger stationary entanglement of optical and mechanical modes can be obtained and the entanglement increases with the increasing parametric gain. Especially, the degree of entanglement between the two cavity fields is more pronouncedly enhanced. Moreover, for a fixed parametric gain, the entanglement of distant cavity optomechanical systems increases as the input laser power is increased.

  4. Parametric amplification by coupled flux qubits

    SciTech Connect

    Rehák, M.; Neilinger, P.; Grajcar, M.; Oelsner, G.; Hübner, U.; Meyer, H.-G.; Il'ichev, E.

    2014-04-21

    We report parametric amplification of a microwave signal in a Kerr medium formed from superconducting qubits. Two mutually coupled flux qubits, embedded in the current antinode of a superconducting coplanar waveguide resonator, are used as a nonlinear element. Shared Josephson junctions provide the qubit-resonator coupling, resulting in a device with a tunable Kerr constant (up to 3 × 10{sup −3}) and a measured gain of about 20 dB. This arrangement represents a unit cell which can be straightforwardly extended to a quasi one-dimensional quantum metamaterial with large tunable Kerr nonlinearity, providing a basis for implementation of wide-band travelling wave parametric amplifiers.

  5. A multimode electromechanical parametric resonator array

    PubMed Central

    Mahboob, I.; Mounaix, M.; Nishiguchi, K.; Fujiwara, A.; Yamaguchi, H.

    2014-01-01

    Electromechanical resonators have emerged as a versatile platform in which detectors with unprecedented sensitivities and quantum mechanics in a macroscopic context can be developed. These schemes invariably utilise a single resonator but increasingly the concept of an array of electromechanical resonators is promising a wealth of new possibilities. In spite of this, experimental realisations of such arrays have remained scarce due to the formidable challenges involved in their fabrication. In a variation to this approach, we identify 75 harmonic vibration modes in a single electromechanical resonator of which 7 can also be parametrically excited. The parametrically resonating modes exhibit vibrations with only 2 oscillation phases which are used to build a binary information array. We exploit this array to execute a mechanical byte memory, a shift-register and a controlled-NOT gate thus vividly illustrating the availability and functionality of an electromechanical resonator array by simply utilising higher order vibration modes. PMID:24658349

  6. Rayleigh-type parametric chemical oscillation

    SciTech Connect

    Ghosh, Shyamolina; Ray, Deb Shankar

    2015-09-28

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

  7. Dynamics of weakly coupled parametrically forced oscillators

    NASA Astrophysics Data System (ADS)

    Salgado Sánchez, P.; Porter, J.; Tinao, I.; Laverón-Simavilla, A.

    2016-08-01

    The dynamics of two weakly coupled parametric oscillators are studied in the neighborhood of the primary subharmonic instability. The nature of both primary and secondary instabilities depends in a critical way on the permutation symmetries, if any, that remain after coupling is considered, and this depends on the relative phases of the parametric forcing terms. Detailed bifurcation sets, revealing a complex series of transitions organized in part by Bogdanov-Takens points, are calculated for representative sets of parameters. In the particular case of out-of-phase forcing the predictions of the coupled oscillator model are compared with direct numerical simulations and with recent experiments on modulated cross waves. Both the initial Hopf bifurcation and the subsequent saddle-node heteroclinic bifurcation are confirmed.

  8. Diode-pumped optical parametric oscillator

    SciTech Connect

    Geiger, A.R.; Hemmati, H.; Farr, W.H.

    1996-02-01

    Diode-pumped optical parametric oscillation has been demonstrated for the first time to our knowledge in a single Nd:MgO:LiNbO{sub 3} nonlinear crystal. The crystal is pumped by a semiconductor diode laser array at 812 nm. The Nd{sup 3+} ions absorb the 812-nm radiation to generate 1084-nm laser oscillation. On internal {ital Q} switching the 1084-nm radiation pumps the LiNbO{sub 3} host crystal that is angle cut at 46.5{degree} and generates optical parametric oscillation. The oscillation threshold that is due to the 1084-nm laser pump with a pulse length of 80 ns in a 1-mm-diameter beam was measured to be {approx_equal}1 mJ and produced 0.5-mJ output at 3400-nm signal wavelength. {copyright} {ital 1996 Optical Society of America.}

  9. Rayleigh-type parametric chemical oscillation

    NASA Astrophysics Data System (ADS)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2015-09-01

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

  10. Nondegenerate optical parametric chirped pulse amplifier

    DOEpatents

    Jovanovic, Igor; Ebbers, Christopher A.

    2005-03-22

    A system provides an input pump pulse and a signal pulse. A first dichroic beamsplitter is highly reflective for the input signal pulse and highly transmissive for the input pump pulse. A first optical parametric amplifier nonlinear crystal transfers part of the energy from the input pump pulse to the input signal pulse resulting in a first amplified signal pulse and a first depleted pump pulse. A second dichroic beamsplitter is highly reflective for the first amplified signal pulse and highly transmissive for the first depleted pump pulse. A second optical parametric amplifier nonlinear crystal transfers part of the energy from the first depleted pump pulse to the first amplified signal pulse resulting in a second amplified signal pulse and a second depleted pump pulse. A third dichroic beamsplitter receives the second amplified signal pulse and the second depleted pump pulse. The second depleted pump pulse is discarded.

  11. Rayleigh-type parametric chemical oscillation.

    PubMed

    Ghosh, Shyamolina; Ray, Deb Shankar

    2015-09-28

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions.

  12. Dynamics of weakly coupled parametrically forced oscillators.

    PubMed

    Salgado Sánchez, P; Porter, J; Tinao, I; Laverón-Simavilla, A

    2016-08-01

    The dynamics of two weakly coupled parametric oscillators are studied in the neighborhood of the primary subharmonic instability. The nature of both primary and secondary instabilities depends in a critical way on the permutation symmetries, if any, that remain after coupling is considered, and this depends on the relative phases of the parametric forcing terms. Detailed bifurcation sets, revealing a complex series of transitions organized in part by Bogdanov-Takens points, are calculated for representative sets of parameters. In the particular case of out-of-phase forcing the predictions of the coupled oscillator model are compared with direct numerical simulations and with recent experiments on modulated cross waves. Both the initial Hopf bifurcation and the subsequent saddle-node heteroclinic bifurcation are confirmed.

  13. Rayleigh-type parametric chemical oscillation.

    PubMed

    Ghosh, Shyamolina; Ray, Deb Shankar

    2015-09-28

    We consider a nonlinear chemical dynamical system of two phase space variables in a stable steady state. When the system is driven by a time-dependent sinusoidal forcing of a suitable scaling parameter at a frequency twice the output frequency and the strength of perturbation exceeds a threshold, the system undergoes sustained Rayleigh-type periodic oscillation, wellknown for parametric oscillation in pipe organs and distinct from the usual forced quasiperiodic oscillation of a damped nonlinear system where the system is oscillatory even in absence of any external forcing. Our theoretical analysis of the parametric chemical oscillation is corroborated by full numerical simulation of two well known models of chemical dynamics, chlorite-iodine-malonic acid and iodine-clock reactions. PMID:26429035

  14. Parametric Model of an Aerospike Rocket Engine

    NASA Technical Reports Server (NTRS)

    Korte, J. J.

    2000-01-01

    A suite of computer codes was assembled to simulate the performance of an aerospike engine and to generate the engine input for the Program to Optimize Simulated Trajectories. First an engine simulator module was developed that predicts the aerospike engine performance for a given mixture ratio, power level, thrust vectoring level, and altitude. This module was then used to rapidly generate the aerospike engine performance tables for axial thrust, normal thrust, pitching moment, and specific thrust. Parametric engine geometry was defined for use with the engine simulator module. The parametric model was also integrated into the iSIGHT multidisciplinary framework so that alternate designs could be determined. The computer codes were used to support in-house conceptual studies of reusable launch vehicle designs.

  15. Parametric Model of an Aerospike Rocket Engine

    NASA Technical Reports Server (NTRS)

    Korte, J. J.

    2000-01-01

    A suite of computer codes was assembled to simulate the performance of an aerospike engine and to generate the engine input for the Program to Optimize Simulated Trajectories. First an engine simulator module was developed that predicts the aerospike engine performance for a given mixture ratio, power level, thrust vectoring level, and altitude. This module was then used to rapidly generate the aerospike engine performance tables for axial thrust, normal thrust, pitching moment, and specific thrust. Parametric engine geometry was defined for use with the engine simulator module. The parametric model was also integrated into the iSIGHTI multidisciplinary framework so that alternate designs could be determined. The computer codes were used to support in-house conceptual studies of reusable launch vehicle designs.

  16. SEC sensor parametric test and evaluation system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This system provides the necessary automated hardware required to carry out, in conjunction with the existing 70 mm SEC television camera, the sensor evaluation tests which are described in detail. The Parametric Test Set (PTS) was completed and is used in a semiautomatic data acquisition and control mode to test the development of the 70 mm SEC sensor, WX 32193. Data analysis of raw data is performed on the Princeton IBM 360-91 computer.

  17. Wavelength-doubling optical parametric oscillator

    DOEpatents

    Armstrong, Darrell J.; Smith, Arlee V.

    2007-07-24

    A wavelength-doubling optical parametric oscillator (OPO) comprising a type II nonlinear optical medium for generating a pair of degenerate waves at twice a pump wavelength and a plurality of mirrors for rotating the polarization of one wave by 90 degrees to produce a wavelength-doubled beam with an increased output energy by coupling both of the degenerate waves out of the OPO cavity through the same output coupler following polarization rotation of one of the degenerate waves.

  18. Beam splitter coupled CDSE optical parametric oscillator

    DOEpatents

    Levinos, Nicholas J.; Arnold, George P.

    1980-01-01

    An optical parametric oscillator is disclosed in which the resonant radiation is separated from the pump and output radiation so that it can be manipulated without interfering with them. Thus, for example, very narrow band output may readily be achieved by passing the resonant radiation through a line narrowing device which does not in itself interfere with either the pump radiation or the output radiation.

  19. Parametric study of laser photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  20. Parametric instabilities in large nonuniform laser plasmas

    SciTech Connect

    Baldis, H.A.; Montgomery, D.S.; Moody, J.D.; Estabrook, K.G.; Berger, R.L.; Kruer, W.L.; Labaune, C.; Batha, S.H.

    1992-09-01

    The study of parametric instabilities in laser plasmas is of vital importance for inertial confinement fusion (ICF). The long scale-length plasma encountered in the corona of an ICF target provides ideal conditions for the growth of instabilities such as stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), and filamentation. These instabilities can have detrimental effects in ICF and their characterization and understanding is of importance. Scattering instabilities are driven through a feedback loop by which the beating between the electromagnetic EM fields of the laser and the scattered light matches the frequency of a local longitudinal mode of the plasma. Any process which interferes with the coherence of this mechanism can substantially alter the behavior of the instability. Of particular interest is the study of laser beam smoothing techniques on parametric instabilities. These techniques are used to improve irradiation uniformity which can suppress hydrodynamic instabilities. Laser beam smoothing techniques have the potential to control the scattering level from parametric instabilities since they provide not only a smoother laser intensity distribution, but also reduced coherence. Beam smoothing techniques that affect the growth of parametric instabilities include spatial smoothing and temporal smoothing by laser bandwidth. Spatial smoothing modifies the phase fronts and temporal distribution of intensities in the focal volume. The transverse intensity spectrum is shifted towards higher spatial wavenumber and can significantly limit the growth of filamentation. Temporal smoothing reduces the coherence time and consequently limits the growth time. Laser bandwidth is required for most smoothing techniques, and can have an independent effect on the instabilities as well.

  1. Conscious Competency: The Mark of a Competent Instructor

    ERIC Educational Resources Information Center

    Gullander, O. E.

    1974-01-01

    The ideal instructor must be totally conscious of the training process, step by step. He is at the third stage of the four-stage learning process, conscious competency. The four stages are unconscious incompetency, conscious incompetency, conscious competency, and unconscious competency. (AG)

  2. Proposed Core Competencies and Empirical Validation Procedure in Competency Modeling: Confirmation and Classification.

    PubMed

    Baczyńska, Anna K; Rowiński, Tomasz; Cybis, Natalia

    2016-01-01

    Competency models provide insight into key skills which are common to many positions in an organization. Moreover, there is a range of competencies that is used by many companies. Researchers have developed core competency terminology to underline their cross-organizational value. The article presents a theoretical model of core competencies consisting of two main higher-order competencies called performance and entrepreneurship. Each of them consists of three elements: the performance competency includes cooperation, organization of work and goal orientation, while entrepreneurship includes innovativeness, calculated risk-taking and pro-activeness. However, there is lack of empirical validation of competency concepts in organizations and this would seem crucial for obtaining reliable results from organizational research. We propose a two-step empirical validation procedure: (1) confirmation factor analysis, and (2) classification of employees. The sample consisted of 636 respondents (M = 44.5; SD = 15.1). Participants were administered a questionnaire developed for the study purpose. The reliability, measured by Cronbach's alpha, ranged from 0.60 to 0.83 for six scales. Next, we tested the model using a confirmatory factor analysis. The two separate, single models of performance and entrepreneurial orientations fit quite well to the data, while a complex model based on the two single concepts needs further research. In the classification of employees based on the two higher order competencies we obtained four main groups of employees. Their profiles relate to those found in the literature, including so-called niche finders and top performers. Some proposal for organizations is discussed. PMID:27014111

  3. Proposed Core Competencies and Empirical Validation Procedure in Competency Modeling: Confirmation and Classification

    PubMed Central

    Baczyńska, Anna K.; Rowiński, Tomasz; Cybis, Natalia

    2016-01-01

    Competency models provide insight into key skills which are common to many positions in an organization. Moreover, there is a range of competencies that is used by many companies. Researchers have developed core competency terminology to underline their cross-organizational value. The article presents a theoretical model of core competencies consisting of two main higher-order competencies called performance and entrepreneurship. Each of them consists of three elements: the performance competency includes cooperation, organization of work and goal orientation, while entrepreneurship includes innovativeness, calculated risk-taking and pro-activeness. However, there is lack of empirical validation of competency concepts in organizations and this would seem crucial for obtaining reliable results from organizational research. We propose a two-step empirical validation procedure: (1) confirmation factor analysis, and (2) classification of employees. The sample consisted of 636 respondents (M = 44.5; SD = 15.1). Participants were administered a questionnaire developed for the study purpose. The reliability, measured by Cronbach’s alpha, ranged from 0.60 to 0.83 for six scales. Next, we tested the model using a confirmatory factor analysis. The two separate, single models of performance and entrepreneurial orientations fit quite well to the data, while a complex model based on the two single concepts needs further research. In the classification of employees based on the two higher order competencies we obtained four main groups of employees. Their profiles relate to those found in the literature, including so-called niche finders and top performers. Some proposal for organizations is discussed. PMID:27014111

  4. Proposed Core Competencies and Empirical Validation Procedure in Competency Modeling: Confirmation and Classification.

    PubMed

    Baczyńska, Anna K; Rowiński, Tomasz; Cybis, Natalia

    2016-01-01

    Competency models provide insight into key skills which are common to many positions in an organization. Moreover, there is a range of competencies that is used by many companies. Researchers have developed core competency terminology to underline their cross-organizational value. The article presents a theoretical model of core competencies consisting of two main higher-order competencies called performance and entrepreneurship. Each of them consists of three elements: the performance competency includes cooperation, organization of work and goal orientation, while entrepreneurship includes innovativeness, calculated risk-taking and pro-activeness. However, there is lack of empirical validation of competency concepts in organizations and this would seem crucial for obtaining reliable results from organizational research. We propose a two-step empirical validation procedure: (1) confirmation factor analysis, and (2) classification of employees. The sample consisted of 636 respondents (M = 44.5; SD = 15.1). Participants were administered a questionnaire developed for the study purpose. The reliability, measured by Cronbach's alpha, ranged from 0.60 to 0.83 for six scales. Next, we tested the model using a confirmatory factor analysis. The two separate, single models of performance and entrepreneurial orientations fit quite well to the data, while a complex model based on the two single concepts needs further research. In the classification of employees based on the two higher order competencies we obtained four main groups of employees. Their profiles relate to those found in the literature, including so-called niche finders and top performers. Some proposal for organizations is discussed.

  5. A variable parameter parametric snake method

    NASA Astrophysics Data System (ADS)

    Marouf, A.; Houacine, A.

    2015-12-01

    In this paper, we introduce a new approach to parametric snake method by using variable snake parameters. Adopting fixed parameter values for all points of the snake, as usual, constitutes by itself a limitation that leads to poor performances in terms of convergence and tracking properties. A more adapted choice should be the one that allows selection depending on the image region properties as on the contour shape and position. However, such variability is not an easy task in general and a precise method need to be defined to assure contour point dependent tuning at iterations. We were particularly interested in applying this idea to the recently presented parametric method [1]. In the work mentioned, an attraction term is used to improve the convergence of the standard parametric snake without a significant increase in computational load. We show here, that improved performances can ensue from applying variable parameter concepts. For this purpose, the method is first analyzed and then a procedure is developed to assure an automatic variable parameter tuning. The interest of our approach is illustrated through object segmentation results.

  6. Parametric Cost Models for Space Telescopes

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Henrichs, Todd; Dollinger, Courtney

    2010-01-01

    Multivariable parametric cost models for space telescopes provide several benefits to designers and space system project managers. They identify major architectural cost drivers and allow high-level design trades. They enable cost-benefit analysis for technology development investment. And, they provide a basis for estimating total project cost. A survey of historical models found that there is no definitive space telescope cost model. In fact, published models vary greatly [1]. Thus, there is a need for parametric space telescopes cost models. An effort is underway to develop single variable [2] and multi-variable [3] parametric space telescope cost models based on the latest available data and applying rigorous analytical techniques. Specific cost estimating relationships (CERs) have been developed which show that aperture diameter is the primary cost driver for large space telescopes; technology development as a function of time reduces cost at the rate of 50% per 17 years; it costs less per square meter of collecting aperture to build a large telescope than a small telescope; and increasing mass reduces cost.

  7. Competency Mapping of the Employees

    NASA Astrophysics Data System (ADS)

    Anisha, N.

    2012-10-01

    Human resource management is a process of bringing people and organizations together so that the goals of each other are met. Nowadays it is not possible to show a good financial or operating report unless your personnel relations are in order. Over the years, highly skilled and knowledge based jobs are increasing while low skilled jobs are decreasing. Competency Mapping is a process of identifying key competencies for an organization, the jobs and functions within it. Competency mapping, the buzz word in any industry is not complicated as it may appear. At the heart of any successful activity lies a competence or skill. In the recent years, various thought leaders in business strategy have emphasized the need to identify what competencies a business needs, in order to compete in a specific environment. In this article explains the why competencies needed and how is measured competency of employees in the organization.

  8. Non-parametric kernel density estimation of species sensitivity distributions in developing water quality criteria of metals.

    PubMed

    Wang, Ying; Wu, Fengchang; Giesy, John P; Feng, Chenglian; Liu, Yuedan; Qin, Ning; Zhao, Yujie

    2015-09-01

    Due to use of different parametric models for establishing species sensitivity distributions (SSDs), comparison of water quality criteria (WQC) for metals of the same group or period in the periodic table is uncertain and results can be biased. To address this inadequacy, a new probabilistic model, based on non-parametric kernel density estimation was developed and optimal bandwidths and testing methods are proposed. Zinc (Zn), cadmium (Cd), and mercury (Hg) of group IIB of the periodic table are widespread in aquatic environments, mostly at small concentrations, but can exert detrimental effects on aquatic life and human health. With these metals as target compounds, the non-parametric kernel density estimation method and several conventional parametric density estimation methods were used to derive acute WQC of metals for protection of aquatic species in China that were compared and contrasted with WQC for other jurisdictions. HC5 values for protection of different types of species were derived for three metals by use of non-parametric kernel density estimation. The newly developed probabilistic model was superior to conventional parametric density estimations for constructing SSDs and for deriving WQC for these metals. HC5 values for the three metals were inversely proportional to atomic number, which means that the heavier atoms were more potent toxicants. The proposed method provides a novel alternative approach for developing SSDs that could have wide application prospects in deriving WQC and use in assessment of risks to ecosystems. PMID:25953609

  9. Non-parametric kernel density estimation of species sensitivity distributions in developing water quality criteria of metals.

    PubMed

    Wang, Ying; Wu, Fengchang; Giesy, John P; Feng, Chenglian; Liu, Yuedan; Qin, Ning; Zhao, Yujie

    2015-09-01

    Due to use of different parametric models for establishing species sensitivity distributions (SSDs), comparison of water quality criteria (WQC) for metals of the same group or period in the periodic table is uncertain and results can be biased. To address this inadequacy, a new probabilistic model, based on non-parametric kernel density estimation was developed and optimal bandwidths and testing methods are proposed. Zinc (Zn), cadmium (Cd), and mercury (Hg) of group IIB of the periodic table are widespread in aquatic environments, mostly at small concentrations, but can exert detrimental effects on aquatic life and human health. With these metals as target compounds, the non-parametric kernel density estimation method and several conventional parametric density estimation methods were used to derive acute WQC of metals for protection of aquatic species in China that were compared and contrasted with WQC for other jurisdictions. HC5 values for protection of different types of species were derived for three metals by use of non-parametric kernel density estimation. The newly developed probabilistic model was superior to conventional parametric density estimations for constructing SSDs and for deriving WQC for these metals. HC5 values for the three metals were inversely proportional to atomic number, which means that the heavier atoms were more potent toxicants. The proposed method provides a novel alternative approach for developing SSDs that could have wide application prospects in deriving WQC and use in assessment of risks to ecosystems.

  10. Testing for Competence. No. 76.

    ERIC Educational Resources Information Center

    Bierschenk, Inger

    The aim of this article is to draw a distinction between qualification and competence. Although academic institutions, organizations, companies, and schools are focusing on competence development as the natural answer to new technical and societal demands, no one has provided a satisfactory operational definition of "competence." A dictionary…

  11. Competency Based Education: A Bibliography.

    ERIC Educational Resources Information Center

    Cox, Helen, Ed.

    This bibliography is a sampling of the types of publications which have appeared recently on the subject of competency based education. Emphasis is given to current (1970-76) materials and to adult career-related competencies. Titles specifically naming some phase of competency-based education are preferred above titles that emphasize performance,…

  12. Guide to Marketing Course Competencies.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum and Resource Center.

    This curriculum guide was developed as a model for schools in Virginia to prepare local programs of studies for the marketing program. In addition to marketing competencies for developing occupational expertise, this curriculum includes foundational competencies important for successful performance in marketing. These baseline competencies address…

  13. Competencies of Undergraduate Business Students

    ERIC Educational Resources Information Center

    Berman, Jeffrey; Ritchie, Leah

    2006-01-01

    The idea that one's competencies are as important as one's qualifications has gained acceptance in both business and academia. Business organizations have developed sophisticated management systems around employee competence. There are education assessment tools that help ascertain students' competencies. In this study, the authors investigated…

  14. Core Competencies for Basic Drafting.

    ERIC Educational Resources Information Center

    Werner, Claire; Calderon, Ray

    These competencies for drafting are designed to cover basic principles and practices for beginning drafters. Each competency appears in a one-page format. It is presented as a goal statement followed by one or more "indicator" statements, which are performance objectives describing an ability that, upon attainment, will establish competency for…

  15. Physical Education Teachers' Cultural Competency

    ERIC Educational Resources Information Center

    Harrison, Louis, Jr.; Carson, Russell L.; Burden, Joe, Jr.

    2010-01-01

    The purpose of this study was to evaluate the common assumption that teachers of color (TOC) are more culturally competent than White teachers by assessing physical education teachers' cultural competency. A secondary purpose was to ascertain the possible differences in cultural competence levels of White teachers in diverse school settings versus…

  16. Are Competency Models a Waste?

    ERIC Educational Resources Information Center

    Dalton, Maxine

    1997-01-01

    Competency models involve a methodology that demonstrates the validity of the model's standards: are people who have the competencies better managers than those who do not? Competency models should no longer be regarded as a panacea and should be only one of the tools used by trainers. (JOW)

  17. Electronics. Occupational Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Occupational Competency Analysis Profile (OCAP) contains a competency list verified by expert workers and developed through a modified DACUM (Developing a Curriculum) involving business, industry, labor, and community agency representatives from Ohio. This OCAP identifies the occupational, academic, and employability skills (competencies)…

  18. Engineering Technologies. State Competency Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This document contains 397 competencies, grouped into 58 units, for tech prep programs in the engineering technologies cluster. The competencies were developed through collaboration of Ohio business, industry, and labor representatives and secondary and associate degree educators. The competencies are rated either "essential" (necessary to ensure…

  19. Minimum Competency in Secondary Education.

    ERIC Educational Resources Information Center

    De Landsheere, Viviane

    1987-01-01

    Discusses issues related to the movement toward minimum competency in secondary education. Addresses the problem of defining minimum competency and the dangers of imposed standardization. Identifies three conceptualizations of minimum competency as: (1) the narrowly educational standpoint, (2) the concern with functional literacy, and (3) a more…

  20. Spiritual Competency Scale: Further Analysis

    ERIC Educational Resources Information Center

    Dailey, Stephanie F.; Robertson, Linda A.; Gill, Carman S.

    2015-01-01

    This article describes a follow-up analysis of the Spiritual Competency Scale, which initially validated ASERVIC's (Association for Spiritual, Ethical and Religious Values in Counseling) spiritual competencies. The study examined whether the factor structure of the Spiritual Competency Scale would be supported by participants (i.e., ASERVIC…

  1. Competency-Based Horticulture: Floriculture.

    ERIC Educational Resources Information Center

    College of DuPage, Glen Ellyn, IL.

    This competency-based horticulture curriculum guide is designed to provide secondary and postsecondary horticulture teachers with a task-oriented program in floriculture. It contains a master resource list, a listing of floriculture resources available from various states, and 89 competency task sheets organized into nine competency areas. These…

  2. Four five-parametric and five four-parametric independent confluent Heun potentials for the stationary Klein-Gordon equation

    NASA Astrophysics Data System (ADS)

    Tarloyan, A. S.; Ishkhanyan, T. A.; Ishkhanyan, A. M.

    2016-04-01

    We present in total fifteen potentials for which the stationary Klein-Gordon equation is solvable in terms of the confluent Heun functions. Because of the symmetry of the confluent Heun equation with respect to the transposition of its regular singularities, only nine of the potentials are independent. Four of these independent potentials are five-parametric. One of them possesses a four-parametric ordinary hypergeometric sub-potential, another one possesses a four-parametric confluent hypergeometric sub-potential, and one potential possesses four-parametric sub-potentials of both hypergeometric types. The fourth five-parametric potential has a three-parametric confluent hypergeometric sub-potential, which is, however, only conditionally integrable. The remaining five independent Heun potentials are four-parametric and have solutions only in terms of irreducible confluent Heun functions.

  3. Should competence be coerced?

    PubMed

    Reamer, F G; Kelly, M J

    1990-01-01

    In this case study, a forensic psychiatric patient is advised by his attorney to avoid trial on criminal charges by refusing further treatment with drugs that are controlling his psychotic symptoms. The case raises the question of whether an involuntarily committed forensic patient has the right to refuse treatment that will restore his competency to stand trial. Reamer, a professor of social work, asks why "a manipulative tactic involving refusal of medication" should be regarded any differently from other disruptive things that criminal defendants may do to postpone or prevent a trial. Kelly, a law school dean, argues that if the patient is competent to understand the consequences of his refusal and to make decisions for himself, he "clearly has the right to refuse treatment of his psychotic symptoms to avoid trial." Unlike Reamer, Kelly believes the patient's attorney may be acting appropriately by advising his client to refuse further medication.

  4. How Insurers Competed in the Affordable Care Act's First Year.

    PubMed

    Swartz, Katherine; Hall, Mark A; Jost, Timothy S

    2015-06-01

    Prior to the Affordable Care Act (ACA), most states' individual health insurance markets were dominated by one or two insurance carriers that had little incentive to compete by providing efficient services. Instead, they competed mainly by screening and selecting people based on their risk of incurring high medical costs. One of the ACA's goals is to encourage carriers to participate in the health insurance marketplaces and to shift the focus from competing based on risk selection to processes that increase consumer value, like improving efficiency of services and quality of care. Focusing on six states--Arkansas, California, Connecticut, Maryland, Montana, and Texas--this brief looks at how carriers are competing in the new marketplaces, namely through cost-sharing and composition of provider networks. PMID:26159009

  5. Competing Orders and Anomalies

    NASA Astrophysics Data System (ADS)

    Moon, Eun-Gook

    2016-08-01

    A conservation law is one of the most fundamental properties in nature, but a certain class of conservation “laws” could be spoiled by intrinsic quantum mechanical effects, so-called quantum anomalies. Profound properties of the anomalies have deepened our understanding in quantum many body systems. Here, we investigate quantum anomaly effects in quantum phase transitions between competing orders and striking consequences of their presence. We explicitly calculate topological nature of anomalies of non-linear sigma models (NLSMs) with the Wess-Zumino-Witten (WZW) terms. The non-perturbative nature is directly related with the ’t Hooft anomaly matching condition: anomalies are conserved in renormalization group flow. By applying the matching condition, we show massless excitations are enforced by the anomalies in a whole phase diagram in sharp contrast to the case of the Landau-Ginzburg-Wilson theory which only has massive excitations in symmetric phases. Furthermore, we find non-perturbative criteria to characterize quantum phase transitions between competing orders. For example, in 4D, we show the two competing order parameter theories, CP(1) and the NLSM with WZW, describe different universality class. Physical realizations and experimental implication of the anomalies are also discussed.

  6. Dissociative state and competence.

    PubMed

    Lin, Yu-Ju; Hsieh, Ming-Hsien; Liu, Shi-Kai

    2007-10-01

    This report presents the results of forensic evaluation of the civil competence of a case of alleged dissociative identity disorder (DID) and discusses whether such dissociative states substantially jeopardize civil competence. A 40-year-old woman claimed that she had had many personalities since her college days. From the age of 37 to 40, she shopped excessively, which left her with millions of dollars of debt. She ascribed her shopping to a certain identity state, over which she had no control. (In this article, we use the term identity state to replace personality as an objective description of a mental state.) She thus raised the petition of civil incompetence. During the forensic evaluation, it was found that the identity states were relatively stable and mutually aware of each other. The switch into another identity state was sometimes under voluntary control. The subject showed consistency and continuity in behavioral patterns across the different identity states, and no matter which identity state she was in, there was no evidence of impairment in her factual knowledge of social situations and her capacity for managing personal affairs. We hence concluded that she was civilly competent despite the claimed DID. Considering that the existence and diagnosis of DID are still under dispute and a diagnosis of DID alone is not sufficient to interdict a persons civil right, important clinical and forensic issues remain to be answered.

  7. Competing Orders and Anomalies.

    PubMed

    Moon, Eun-Gook

    2016-08-08

    A conservation law is one of the most fundamental properties in nature, but a certain class of conservation "laws" could be spoiled by intrinsic quantum mechanical effects, so-called quantum anomalies. Profound properties of the anomalies have deepened our understanding in quantum many body systems. Here, we investigate quantum anomaly effects in quantum phase transitions between competing orders and striking consequences of their presence. We explicitly calculate topological nature of anomalies of non-linear sigma models (NLSMs) with the Wess-Zumino-Witten (WZW) terms. The non-perturbative nature is directly related with the 't Hooft anomaly matching condition: anomalies are conserved in renormalization group flow. By applying the matching condition, we show massless excitations are enforced by the anomalies in a whole phase diagram in sharp contrast to the case of the Landau-Ginzburg-Wilson theory which only has massive excitations in symmetric phases. Furthermore, we find non-perturbative criteria to characterize quantum phase transitions between competing orders. For example, in 4D, we show the two competing order parameter theories, CP(1) and the NLSM with WZW, describe different universality class. Physical realizations and experimental implication of the anomalies are also discussed.

  8. Competing Orders and Anomalies.

    PubMed

    Moon, Eun-Gook

    2016-01-01

    A conservation law is one of the most fundamental properties in nature, but a certain class of conservation "laws" could be spoiled by intrinsic quantum mechanical effects, so-called quantum anomalies. Profound properties of the anomalies have deepened our understanding in quantum many body systems. Here, we investigate quantum anomaly effects in quantum phase transitions between competing orders and striking consequences of their presence. We explicitly calculate topological nature of anomalies of non-linear sigma models (NLSMs) with the Wess-Zumino-Witten (WZW) terms. The non-perturbative nature is directly related with the 't Hooft anomaly matching condition: anomalies are conserved in renormalization group flow. By applying the matching condition, we show massless excitations are enforced by the anomalies in a whole phase diagram in sharp contrast to the case of the Landau-Ginzburg-Wilson theory which only has massive excitations in symmetric phases. Furthermore, we find non-perturbative criteria to characterize quantum phase transitions between competing orders. For example, in 4D, we show the two competing order parameter theories, CP(1) and the NLSM with WZW, describe different universality class. Physical realizations and experimental implication of the anomalies are also discussed. PMID:27499184

  9. Competing Orders and Anomalies

    PubMed Central

    Moon, Eun-Gook

    2016-01-01

    A conservation law is one of the most fundamental properties in nature, but a certain class of conservation “laws” could be spoiled by intrinsic quantum mechanical effects, so-called quantum anomalies. Profound properties of the anomalies have deepened our understanding in quantum many body systems. Here, we investigate quantum anomaly effects in quantum phase transitions between competing orders and striking consequences of their presence. We explicitly calculate topological nature of anomalies of non-linear sigma models (NLSMs) with the Wess-Zumino-Witten (WZW) terms. The non-perturbative nature is directly related with the ’t Hooft anomaly matching condition: anomalies are conserved in renormalization group flow. By applying the matching condition, we show massless excitations are enforced by the anomalies in a whole phase diagram in sharp contrast to the case of the Landau-Ginzburg-Wilson theory which only has massive excitations in symmetric phases. Furthermore, we find non-perturbative criteria to characterize quantum phase transitions between competing orders. For example, in 4D, we show the two competing order parameter theories, CP(1) and the NLSM with WZW, describe different universality class. Physical realizations and experimental implication of the anomalies are also discussed. PMID:27499184

  10. Tremor Detection Using Parametric and Non-Parametric Spectral Estimation Methods: A Comparison with Clinical Assessment

    PubMed Central

    Martinez Manzanera, Octavio; Elting, Jan Willem; van der Hoeven, Johannes H.; Maurits, Natasha M.

    2016-01-01

    In the clinic, tremor is diagnosed during a time-limited process in which patients are observed and the characteristics of tremor are visually assessed. For some tremor disorders, a more detailed analysis of these characteristics is needed. Accelerometry and electromyography can be used to obtain a better insight into tremor. Typically, routine clinical assessment of accelerometry and electromyography data involves visual inspection by clinicians and occasionally computational analysis to obtain objective characteristics of tremor. However, for some tremor disorders these characteristics may be different during daily activity. This variability in presentation between the clinic and daily life makes a differential diagnosis more difficult. A long-term recording of tremor by accelerometry and/or electromyography in the home environment could help to give a better insight into the tremor disorder. However, an evaluation of such recordings using routine clinical standards would take too much time. We evaluated a range of techniques that automatically detect tremor segments in accelerometer data, as accelerometer data is more easily obtained in the home environment than electromyography data. Time can be saved if clinicians only have to evaluate the tremor characteristics of segments that have been automatically detected in longer daily activity recordings. We tested four non-parametric methods and five parametric methods on clinical accelerometer data from 14 patients with different tremor disorders. The consensus between two clinicians regarding the presence or absence of tremor on 3943 segments of accelerometer data was employed as reference. The nine methods were tested against this reference to identify their optimal parameters. Non-parametric methods generally performed better than parametric methods on our dataset when optimal parameters were used. However, one parametric method, employing the high frequency content of the tremor bandwidth under consideration

  11. Tremor Detection Using Parametric and Non-Parametric Spectral Estimation Methods: A Comparison with Clinical Assessment.

    PubMed

    Martinez Manzanera, Octavio; Elting, Jan Willem; van der Hoeven, Johannes H; Maurits, Natasha M

    2016-01-01

    In the clinic, tremor is diagnosed during a time-limited process in which patients are observed and the characteristics of tremor are visually assessed. For some tremor disorders, a more detailed analysis of these characteristics is needed. Accelerometry and electromyography can be used to obtain a better insight into tremor. Typically, routine clinical assessment of accelerometry and electromyography data involves visual inspection by clinicians and occasionally computational analysis to obtain objective characteristics of tremor. However, for some tremor disorders these characteristics may be different during daily activity. This variability in presentation between the clinic and daily life makes a differential diagnosis more difficult. A long-term recording of tremor by accelerometry and/or electromyography in the home environment could help to give a better insight into the tremor disorder. However, an evaluation of such recordings using routine clinical standards would take too much time. We evaluated a range of techniques that automatically detect tremor segments in accelerometer data, as accelerometer data is more easily obtained in the home environment than electromyography data. Time can be saved if clinicians only have to evaluate the tremor characteristics of segments that have been automatically detected in longer daily activity recordings. We tested four non-parametric methods and five parametric methods on clinical accelerometer data from 14 patients with different tremor disorders. The consensus between two clinicians regarding the presence or absence of tremor on 3943 segments of accelerometer data was employed as reference. The nine methods were tested against this reference to identify their optimal parameters. Non-parametric methods generally performed better than parametric methods on our dataset when optimal parameters were used. However, one parametric method, employing the high frequency content of the tremor bandwidth under consideration

  12. Competencies for disaster mental health.

    PubMed

    King, Richard V; Burkle, Frederick M; Walsh, Lauren E; North, Carol S

    2015-03-01

    Competencies for disaster mental health are essential to domestic and international disaster response capabilities. Numerous consensus-based competency sets for disaster health workers exist, but no prior study identifies and discusses competency sets pertaining specifically to disaster mental health. Relevant competency sets were identified via MEDLINE, PsycINFO, EBSCO, and Google Scholar searches. Sixteen competency sets are discussed, some providing core competencies for all disaster responders and others for specific responder groups within particular professions or specialties. Competency sets specifically for disaster mental health professionals are lacking, with the exception of one set that focused only on cultural competence. The identified competency sets provide guidance for educators in developing disaster mental health curricula and for disaster health workers seeking education and training in disaster mental health. Valid, criterion-based competencies are required to guide selection and training of mental health professionals for the disaster mental health workforce. In developing these competencies, consideration should be given to the requirements of both domestic and international disaster response efforts.

  13. Seven essential strategies for promoting and sustaining systemic cultural competence.

    PubMed

    Delphin-Rittmon, Miriam E; Andres-Hyman, Raquel; Flanagan, Elizabeth H; Davidson, Larry

    2013-03-01

    Racial and ethnic disparities are disturbing facets of the American healthcare system that document the reality of unequal treatment. Research consistently shows that patients of color experience poorer quality of care and health outcomes contributing to increased risks and accelerated mortality rates relative to their white counterparts. While initially conceptualized as an approach for increasing the responsiveness of children's behavioral health care, cultural competence has been adopted as a key strategy for eliminating racial and ethnic health disparities across the healthcare system. However, cultural competence research and practices largely focus on improving provider competencies, while agency and system level approaches for meeting the service needs of diverse populations are given less attention. In this article we offer seven essential strategies for promoting and sustaining organizational and systemic cultural competence. These strategies are to: (1) Provide executive level support and accountability, (2) Foster patient, community and stakeholder participation and partnerships, (3) Conduct organizational cultural competence assessments, (4) Develop incremental and realistic cultural competence action plans, (5) Ensure linguistic competence, (6) Diversify, develop, and retain a culturally competent workforce, and (7) Develop an agency or system strategy for managing staff and patient grievances. For each strategy we offer several recommendations for implementation. PMID:22581030

  14. Seven essential strategies for promoting and sustaining systemic cultural competence.

    PubMed

    Delphin-Rittmon, Miriam E; Andres-Hyman, Raquel; Flanagan, Elizabeth H; Davidson, Larry

    2013-03-01

    Racial and ethnic disparities are disturbing facets of the American healthcare system that document the reality of unequal treatment. Research consistently shows that patients of color experience poorer quality of care and health outcomes contributing to increased risks and accelerated mortality rates relative to their white counterparts. While initially conceptualized as an approach for increasing the responsiveness of children's behavioral health care, cultural competence has been adopted as a key strategy for eliminating racial and ethnic health disparities across the healthcare system. However, cultural competence research and practices largely focus on improving provider competencies, while agency and system level approaches for meeting the service needs of diverse populations are given less attention. In this article we offer seven essential strategies for promoting and sustaining organizational and systemic cultural competence. These strategies are to: (1) Provide executive level support and accountability, (2) Foster patient, community and stakeholder participation and partnerships, (3) Conduct organizational cultural competence assessments, (4) Develop incremental and realistic cultural competence action plans, (5) Ensure linguistic competence, (6) Diversify, develop, and retain a culturally competent workforce, and (7) Develop an agency or system strategy for managing staff and patient grievances. For each strategy we offer several recommendations for implementation.

  15. Multicutter machining of compound parametric surfaces

    NASA Astrophysics Data System (ADS)

    Hatna, Abdelmadjid; Grieve, R. J.; Broomhead, P.

    2000-10-01

    Parametric free forms are used in industries as disparate as footwear, toys, sporting goods, ceramics, digital content creation, and conceptual design. Optimizing tool path patterns and minimizing the total machining time is a primordial issue in numerically controlled (NC) machining of free form surfaces. We demonstrate in the present work that multi-cutter machining can achieve as much as 60% reduction in total machining time for compound sculptured surfaces. The given approach is based upon the pre-processing as opposed to the usual post-processing of surfaces for the detection and removal of interference followed by precise tracking of unmachined areas.

  16. Lottery spending: a non-parametric analysis.

    PubMed

    Garibaldi, Skip; Frisoli, Kayla; Ke, Li; Lim, Melody

    2015-01-01

    We analyze the spending of individuals in the United States on lottery tickets in an average month, as reported in surveys. We view these surveys as sampling from an unknown distribution, and we use non-parametric methods to compare properties of this distribution for various demographic groups, as well as claims that some properties of this distribution are constant across surveys. We find that the observed higher spending by Hispanic lottery players can be attributed to differences in education levels, and we dispute previous claims that the top 10% of lottery players consistently account for 50% of lottery sales.

  17. Ground-Based Telescope Parametric Cost Model

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Rowell, Ginger Holmes

    2004-01-01

    A parametric cost model for ground-based telescopes is developed using multi-variable statistical analysis, The model includes both engineering and performance parameters. While diameter continues to be the dominant cost driver, other significant factors include primary mirror radius of curvature and diffraction limited wavelength. The model includes an explicit factor for primary mirror segmentation and/or duplication (i.e.. multi-telescope phased-array systems). Additionally, single variable models based on aperture diameter are derived. This analysis indicates that recent mirror technology advances have indeed reduced the historical telescope cost curve.

  18. Parametric uncertain identification of a robotic system

    NASA Astrophysics Data System (ADS)

    Angel, L.; Viola, J.; Hernández, C.

    2016-07-01

    This paper presents the parametric uncertainties identification of a robotic system of one degree of freedom. A MSC-ADAMS / MATLAB co-simulation model was built to simulate the uncertainties that affect the robotic system. For a desired trajectory, a set of dynamic models of the system was identified in presence of variations in the mass, length and friction of the system employing least squares method. Using the input-output linearization technique a linearized model plant was defined. Finally, the maximum multiplicative uncertainty of the system was modelled giving the controller desired design conditions to achieve a robust stability and performance of the closed loop system.

  19. Automatic Parametric Testing Of Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Jennings, Glenn A.; Pina, Cesar A.

    1989-01-01

    Computer program for parametric testing saves time and effort in research and development of integrated circuits. Software system automatically assembles various types of test structures and lays them out on silicon chip, generates sequency of test instructions, and interprets test data. Employs self-programming software; needs minimum of human intervention. Adapted to needs of different laboratories and readily accommodates new test structures. Program codes designed to be adaptable to most computers and test equipment now in use. Written in high-level languages to enhance transportability.

  20. Parametric study of modern airship productivity

    NASA Technical Reports Server (NTRS)

    Ardema, M. D.; Flaig, K.

    1980-01-01

    A method for estimating the specific productivity of both hybrid and fully buoyant airships is developed. Various methods of estimating structural weight of deltoid hybrids are discussed and a derived weight estimating relationship is presented. Specific productivity is used as a figure of merit in a parametric study of fully buoyant ellipsoidal and deltoid hybrid semi-buoyant vehicles. The sensitivity of results as a function of assumptions is also determined. No airship configurations were found to have superior specific productivity to transport airplanes.

  1. Noise rise in nondegenerate parametric amplifiers

    SciTech Connect

    Bryant, P.H. ); Movshovich, R.; Yurke, B. )

    1991-05-20

    The noise-rise phenomenon is a long-standing problem that was first observed in Josephson-junction-parametric amplifiers over ten years ago. We present here a case where noise-rise data from a Josephson junction is successfully explained, using a theory based on the universal properties of a dynamical system operated near a bifurcation point. The experiment and theory presented here is for a bifurcation of the Hopf type, a case not discussed previously. The predicted behavior is qualitatively different from that of previously studied bifurcations.

  2. Detecting Atlantic herring by parametric sonar.

    PubMed

    Godo, Olav Rune; Foote, Kenneth G; Dybedal, Johnny; Tenningen, Eirik; Patel, Ruben

    2010-04-01

    The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1-6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools observed in situ in December 2008 and November 2009 are presented. These agree well with echograms of volume backscattering strength derived simultaneously with the narrowband Simrad EK60/18- and 38-kHz scientific echo sounder, also giving insight into herring avoidance behavior in relation to survey vessel passage. Progress in rendering the TOPAS echograms quantitative is described. PMID:20369983

  3. Parametric modulation of an atomic magnetometer

    PubMed Central

    Li, Zhimin; Wakai, Ronald T.; Walker, Thad G.

    2012-01-01

    The authors report on a rubidium atomic magnetometer designed for use in a shielded environment. Operating in the spin-exchange relaxation-free regime, the magnetometer utilizes parametric modulation of the z-magnetic field to suppress noise associated with airflow through the oven and to simultaneously detect x- and y-field components, using a single probe beam, with minimal loss of sensitivity and bandwidth. A white noise level of 60 fT/(Hz)1/2 was achieved. PMID:22942436

  4. Spectral and parametric averaging for integrable systems

    NASA Astrophysics Data System (ADS)

    Ma, Tao; Serota, R. A.

    2015-05-01

    We analyze two theoretical approaches to ensemble averaging for integrable systems in quantum chaos, spectral averaging (SA) and parametric averaging (PA). For SA, we introduce a new procedure, namely, rescaled spectral averaging (RSA). Unlike traditional SA, it can describe the correlation function of spectral staircase (CFSS) and produce persistent oscillations of the interval level number variance (IV). PA while not as accurate as RSA for the CFSS and IV, can also produce persistent oscillations of the global level number variance (GV) and better describes saturation level rigidity as a function of the running energy. Overall, it is the most reliable method for a wide range of statistics.

  5. Detecting Atlantic herring by parametric sonar.

    PubMed

    Godo, Olav Rune; Foote, Kenneth G; Dybedal, Johnny; Tenningen, Eirik; Patel, Ruben

    2010-04-01

    The difference-frequency band of the Kongsberg TOPAS PS18 parametric sub-bottom profiling sonar, nominally 1-6 kHz, is being used to observe Atlantic herring. Representative TOPAS echograms of herring layers and schools observed in situ in December 2008 and November 2009 are presented. These agree well with echograms of volume backscattering strength derived simultaneously with the narrowband Simrad EK60/18- and 38-kHz scientific echo sounder, also giving insight into herring avoidance behavior in relation to survey vessel passage. Progress in rendering the TOPAS echograms quantitative is described.

  6. White-light parametric instabilities in plasmas.

    PubMed

    Santos, J E; Silva, L O; Bingham, R

    2007-06-01

    Parametric instabilities driven by partially coherent radiation in plasmas are described by a generalized statistical Wigner-Moyal set of equations, formally equivalent to the full wave equation, coupled to the plasma fluid equations. A generalized dispersion relation for stimulated Raman scattering driven by a partially coherent pump field is derived, revealing a growth rate dependence, with the coherence width sigma of the radiation field, scaling with 1/sigma for backscattering (three-wave process), and with 1/sigma1/2 for direct forward scattering (four-wave process). Our results demonstrate the possibility to control the growth rates of these instabilities by properly using broadband pump radiation fields.

  7. Lottery Spending: A Non-Parametric Analysis

    PubMed Central

    Garibaldi, Skip; Frisoli, Kayla; Ke, Li; Lim, Melody

    2015-01-01

    We analyze the spending of individuals in the United States on lottery tickets in an average month, as reported in surveys. We view these surveys as sampling from an unknown distribution, and we use non-parametric methods to compare properties of this distribution for various demographic groups, as well as claims that some properties of this distribution are constant across surveys. We find that the observed higher spending by Hispanic lottery players can be attributed to differences in education levels, and we dispute previous claims that the top 10% of lottery players consistently account for 50% of lottery sales. PMID:25642699

  8. A Cartesian parametrization for the numerical analysis of material instability

    DOE PAGES

    Mota, Alejandro; Chen, Qiushi; Foulk, III, James W.; Ostien, Jakob T.; Lai, Zhengshou

    2016-02-25

    We examine four parametrizations of the unit sphere in the context of material stability analysis by means of the singularity of the acoustic tensor. We then propose a Cartesian parametrization for vectors that lie a cube of side length two and use these vectors in lieu of unit normals to test for the loss of the ellipticity condition. This parametrization is then used to construct a tensor akin to the acoustic tensor. It is shown that both of these tensors become singular at the same time and in the same planes in the presence of a material instability. Furthermore, themore » performance of the Cartesian parametrization is compared against the other parametrizations, with the results of these comparisons showing that in general, the Cartesian parametrization is more robust and more numerically efficient than the others.« less

  9. Efficient optical parametric generation in an organomineral crystal

    NASA Astrophysics Data System (ADS)

    Samuel, I. D. W.; Villacampa, B.; Josse, D.; Khodja, S.; Zyss, J.

    1995-04-01

    Organomineral crystals are engineered to combine the favorable properties of organic and inorganic materials. High gain parametric emission and amplification at telecommunications wavelengths are demonstrated in an organomineral crystal, 2-amino-5-nitropyridinium-dihydrogen phosphate. A novel angle-noncritical type-II phase-matching configuration is observed in parametric emission, and parametric amplification is demonstrated at 1.5 μm.

  10. Characterization of a multimode coplanar waveguide parametric amplifier

    SciTech Connect

    Simoen, M. Krantz, P.; Bylander, Jonas; Shumeiko, V.; Delsing, P.; Chang, C. W. S.; Wilson, C. M.; Wustmann, W.

    2015-10-21

    We characterize a Josephson parametric amplifier based on a flux-tunable quarter-wavelength resonator. The fundamental resonance frequency is ∼1 GHz, but we use higher modes of the resonator for our measurements. An on-chip tuning line allows for magnetic flux pumping of the amplifier. We investigate and compare degenerate parametric amplification, involving a single mode, and nondegenerate parametric amplification, using a pair of modes. We show that we reach quantum-limited noise performance in both cases.

  11. Cascade frequency generation regime in an optical parametric oscillator

    SciTech Connect

    Kolker, D B; Dmitriev, Aleksandr K; Gorelik, P; Vong, Franko; Zondy, J J

    2009-05-31

    In a parametric oscillator of a special two-sectional design based on a lithium niobate periodic structure, a cascade frequency generation regime was observed in which a signal wave pumped a secondary parametric oscillator, producing secondary signal and idler waves. The secondary parametric oscillator can be tuned in a broad range of {approx}200 nm with respect to a fixed wavelength of the primary idler wave. (nonlinear optical phenomena)

  12. Experimental demonstration of nanosecond optical parametric amplifier in YCOB

    NASA Astrophysics Data System (ADS)

    Li, Huanhuan; Li, Shiguang; Ma, Xiuhua; Zhu, Xiaolei; Tu, Xiaoniu; Zheng, Yanqing

    2013-05-01

    In this letter, we provide the experimental demonstration of nanosecond optical parametric amplification in YCOB centered at 1572 nm. The optical gain characterization of YCOB crystal was simulated and tested in this optical parametric conversion. A saturated OPA gain of 2.4 was obtained. The results confirm that YCOB crystal has the potential to be used in a high-energy cascade of MOPA parametric amplifiers at 1572 nm.

  13. Study of Vertical Sound Image Control Using Parametric Loudspeakers

    NASA Astrophysics Data System (ADS)

    Shimizu, Kazuhiro; Itou, Kouki; Aoki, Shigeaki

    A parametric loudspeaker is known as a super-directivity loudspeaker. So far, the applications have been limited monaural reproduction sound system. We had discussed characteristics of stereo reproduction with two parametric loudspeakers. In this paper, the sound localization in the vertical direction using the parametric loudspeakers was confirmed. The direction of sound localization was able to be controlled. The results were similar as in using ordinary loudspeakers. However, by setting the parametric loudspeaker 5 degrees rightward, the direction of sound localization moved about 20 degrees rightward. The measured ILD (Interaural Level Difference) using a dummy head were analyzed.

  14. Parametric robust control and system identification: Unified approach

    NASA Technical Reports Server (NTRS)

    Keel, Leehyun

    1994-01-01

    Despite significant advancement in the area of robust parametric control, the problem of synthesizing such a controller is still a wide open problem. Thus, we attempt to give a solution to this important problem. Our approach captures the parametric uncertainty as an H(sub infinity) unstructured uncertainty so that H(sub infinity) synthesis techniques are applicable. Although the techniques cannot cope with the exact parametric uncertainty, they give a reasonable guideline to model the unstructured uncertainty that contains the parametric uncertainty. An additional loop shaping technique is also introduced to relax its conservatism.

  15. Parametric resonance of intrinsic localized modes in coupled cantilever arrays

    NASA Astrophysics Data System (ADS)

    Kimura, Masayuki; Matsushita, Yasuo; Hikihara, Takashi

    2016-08-01

    In this study, the parametric resonances of pinned intrinsic localized modes (ILMs) were investigated by computing the unstable regions in parameter space consisting of parametric excitation amplitude and frequency. In the unstable regions, the pinned ILMs were observed to lose stability and begin to fluctuate. A nonlinear Klein-Gordon, Fermi-Pasta-Ulam-like, and mixed lattices were investigated. The pinned ILMs, particularly in the mixed lattice, were destabilized by parametric resonances, which were determined by comparing the shapes of the unstable regions with those in the Mathieu differential equation. In addition, traveling ILMs could be generated by parametric excitation.

  16. Optical parametrically gated microscopy in scattering media

    PubMed Central

    Zhao, Youbo; Adie, Steven G.; Tu, Haohua; Liu, Yuan; Graf, Benedikt W.; Chaney, Eric J.; Marjanovic, Marina; Boppart, Stephen A.

    2014-01-01

    High-resolution imaging in turbid media has been limited by the intrinsic compromise between the gating efficiency (removal of multiply-scattered light background) and signal strength in the existing optical gating techniques. This leads to shallow depths due to the weak ballistic signal, and/or degraded resolution due to the strong multiply-scattering background – the well-known trade-off between resolution and imaging depth in scattering samples. In this work, we employ a nonlinear optics based optical parametric amplifier (OPA) to address this challenge. We demonstrate that both the imaging depth and the spatial resolution in turbid media can be enhanced simultaneously by the OPA, which provides a high level of signal gain as well as an inherent nonlinear optical gate. This technology shifts the nonlinear interaction to an optical crystal placed in the detection arm (image plane), rather than in the sample, which can be used to exploit the benefits given by the high-order parametric process and the use of an intense laser field. The coherent process makes the OPA potentially useful as a general-purpose optical amplifier applicable to a wide range of optical imaging techniques. PMID:25321724

  17. Ionization Cooling Using a Parametric Resonance

    SciTech Connect

    Y.S. Derbenev; R.P. Johnson

    2005-05-16

    Muon collider luminosity depends on the number of muons in the storage ring and on the transverse size of the beams in collision. Ionization cooling as it is presently envisioned will not cool the beam sizes sufficiently well to provide adequate luminosity without large muon intensities. A new idea to combine ionization cooling with parametric resonances has been developed that will lead to beams with much smaller sizes so that high luminosity in a muon collider can be achieved with fewer muons. In the linear channel described here, a half integer resonance is induced such that the normal elliptical motion of particles in x-x' phase space becomes hyperbolic, with particles moving to smaller x and larger x' as they pass down the channel. Thin absorbers placed at the focal points of the channel then cool the angular divergence of the beam by the usual ionization cooling mechanism where each absorber is followed by RF cavities. We discuss the theory of Parametric-resonance Ionization Cooling, including the sensitivity to aberrations and the need to start with a beam that has already been cooled adequately.

  18. Airborne Methane Measurements using Optical Parametric Amplifiers

    NASA Astrophysics Data System (ADS)

    Riris, H.; Numata, K.; Li, S.; Wu, S.; Ramanathan, A.; Dawsey, M.; Abshire, J. B.; Kawa, S. R.; Mao, J.

    2012-12-01

    We report on airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planetary bodies. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Carbon and methane emissions from land are expected to increase as permafrost melts exposing millennial-age carbon stocks to respiration (aerobic-CO2 and anaerobic-CH4) and fires. Methane emissions from clathrates in the Arctic Ocean and on land are also likely to respond to climate warming. However, there is considerable uncertainty in present Arctic flux levels, as well as how fluxes will change with the changing environment and more measurements are needed. In this paper we report on an airborne demonstration of atmospheric methane column optical depth measurements at 1.65 μm using widely tunable, seeded optical parametric amplifier (OPA) and a photon counting detector. Our results show good agreement between the experimentally derived optical depth measurements and theoretical calculations and follow the expected changes for aircraft altitudes from 3 to 11 km. The technique has also been used to measure carbon dioxide and monoxide, water vapor, and other trace gases in the near and mid-infrared spectral regions on the ground.

  19. Quantum transformation limits in multiwave parametric interactions

    NASA Astrophysics Data System (ADS)

    Saygin, M. Yu

    2016-10-01

    The possibility to realize multiple nonlinear optical processes in a single crystal as means to produce multicolor quantum states favours stability and compactness of optical settings. Hence, this approach can be advantageous compared to the traditional one based on cascaded arrangement of optical elements. However, it comes with an obstacle—the class of accessible quantum states is narrower than that of the cascade counterpart. In this letter, we study this task using an example of three coupled nonlinear optical processes, namely, one parametric down-conversion and two of sum-frequency generation. To this end, the singular value decomposition has been applied to find the cascade representation of the compound field evolution. We have found the link between the parameters of the multiwave processes and the relevant cascade parameters—beam-splitting and squeezing parameters, by means of which the generated quantum states have been characterized. The relation between the squeezing parameters that has been found in the course of this work shows that the squeezing resource, produced in the parametric down-conversion, is shared among the modes involved in the compound interactions. Moreover, we have shown that the degree of two-mode entanglement carried by the up-converted frequencies cannot exceed that of the down-converted frequencies.

  20. Modeling Personnel Turnover in the Parametric Organization

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.

    1991-01-01

    A primary issue in organizing a new parametric cost analysis function is to determine the skill mix and number of personnel required. The skill mix can be obtained by a functional decomposition of the tasks required within the organization and a matrixed correlation with educational or experience backgrounds. The number of personnel is a function of the skills required to cover all tasks, personnel skill background and cross training, the intensity of the workload for each task, migration through various tasks by personnel along a career path, personnel hiring limitations imposed by management and the applicant marketplace, personnel training limitations imposed by management and personnel capability, and the rate at which personnel leave the organization for whatever reason. Faced with the task of relating all of these organizational facets in order to grow a parametric cost analysis (PCA) organization from scratch, it was decided that a dynamic model was required in order to account for the obvious dynamics of the forming organization. The challenge was to create such a simple model which would be credible during all phases of organizational development. The model development process was broken down into the activities of determining the tasks required for PCA, determining the skills required for each PCA task, determining the skills available in the applicant marketplace, determining the structure of the dynamic model, implementing the dynamic model, and testing the dynamic model.

  1. Degenerate parametric oscillation in quantum membrane optomechanics

    NASA Astrophysics Data System (ADS)

    Benito, Mónica; Sánchez Muñoz, Carlos; Navarrete-Benlloch, Carlos

    2016-02-01

    The promise of innovative applications has triggered the development of many modern technologies capable of exploiting quantum effects. But in addition to future applications, such quantum technologies have already provided us with the possibility of accessing quantum-mechanical scenarios that seemed unreachable just a few decades ago. With this spirit, in this work we show that modern optomechanical setups are mature enough to implement one of the most elusive models in the field of open system dynamics: degenerate parametric oscillation. Introduced in the eighties and motivated by its alleged implementability in nonlinear optical resonators, it rapidly became a paradigm for the study of dissipative phase transitions whose corresponding spontaneously broken symmetry is discrete. However, it was found that the intrinsic multimode nature of optical cavities makes it impossible to experimentally study the model all the way through its phase transition. In contrast, here we show that this long-awaited model can be implemented in the motion of a mechanical object dispersively coupled to the light contained in a cavity, when the latter is properly driven with multichromatic laser light. We focus on membranes as the mechanical element, showing that the main signatures of the degenerate parametric oscillation model can be studied in state-of-the-art setups, thus opening the possibility of analyzing spontaneous symmetry breaking and enhanced metrology in one of the cleanest dissipative phase transitions. In addition, the ideas put forward in this work would allow for the dissipative preparation of squeezed mechanical states.

  2. Brain Signal Variability is Parametrically Modifiable

    PubMed Central

    Garrett, Douglas D.; McIntosh, Anthony R.; Grady, Cheryl L.

    2014-01-01

    Moment-to-moment brain signal variability is a ubiquitous neural characteristic, yet remains poorly understood. Evidence indicates that heightened signal variability can index and aid efficient neural function, but it is not known whether signal variability responds to precise levels of environmental demand, or instead whether variability is relatively static. Using multivariate modeling of functional magnetic resonance imaging-based parametric face processing data, we show here that within-person signal variability level responds to incremental adjustments in task difficulty, in a manner entirely distinct from results produced by examining mean brain signals. Using mixed modeling, we also linked parametric modulations in signal variability with modulations in task performance. We found that difficulty-related reductions in signal variability predicted reduced accuracy and longer reaction times within-person; mean signal changes were not predictive. We further probed the various differences between signal variance and signal means by examining all voxels, subjects, and conditions; this analysis of over 2 million data points failed to reveal any notable relations between voxel variances and means. Our results suggest that brain signal variability provides a systematic task-driven signal of interest from which we can understand the dynamic function of the human brain, and in a way that mean signals cannot capture. PMID:23749875

  3. Supramodal parametric working memory processing in humans.

    PubMed

    Spitzer, Bernhard; Blankenburg, Felix

    2012-03-01

    Previous studies of delayed-match-to-sample (DMTS) frequency discrimination in animals and humans have succeeded in delineating the neural signature of frequency processing in somatosensory working memory (WM). During retention of vibrotactile frequencies, stimulus-dependent single-cell and population activity in prefrontal cortex was found to reflect the task-relevant memory content, whereas increases in occipital alpha activity signaled the disengagement of areas not relevant for the tactile task. Here, we recorded EEG from human participants to determine the extent to which these mechanisms can be generalized to frequency retention in the visual and auditory domains. Subjects performed analogous variants of a DMTS frequency discrimination task, with the frequency information presented either visually, auditorily, or by vibrotactile stimulation. Examining oscillatory EEG activity during frequency retention, we found characteristic topographical distributions of alpha power over visual, auditory, and somatosensory cortices, indicating systematic patterns of inhibition and engagement of early sensory areas, depending on stimulus modality. The task-relevant frequency information, in contrast, was found to be represented in right prefrontal cortex, independent of presentation mode. In each of the three modality conditions, parametric modulations of prefrontal upper beta activity (20-30 Hz) emerged, in a very similar manner as recently found in vibrotactile tasks. Together, the findings corroborate a view of parametric WM as supramodal internal scaling of abstract quantity information and suggest strong relevance of previous evidence from vibrotactile work for a more general framework of quantity processing in human working memory.

  4. Application of parametric and non-parametric statistics to sounding rocket dispersion including large sample and small sample theory

    NASA Technical Reports Server (NTRS)

    Mcgarvey, J. F.

    1976-01-01

    Analytical methods for obtaining large and small samples to be used in sounding rocket dispersion statistics are described. When the distribution of the parent population is assumed known, a method is called parametric. When no assumption is made about the parent population, the method is called nonparametric. Parametric and nonparametric methods are given for both large and small samples. The assumed distribution for the parametric case will be normal and it is shown that sample nonparametric theory is easier to apply in many cases, giving essentially the same results as parametric theory. The method is applied to the dispersion of NASA sounding rockets from 1959 to 1974.

  5. Is aspect ratio sufficient to classify intra-aneurysmal hemodynamics- a parametric approach

    NASA Astrophysics Data System (ADS)

    Durka, Michael; Robertson, Anne

    2013-11-01

    Intracranial aneurysms are a vascular pathology in which a localized bulge is formed in the arterial wall, most often in a saccular shape. It is believed that the blood flow field within the aneurysm plays a critical role in the degradation of the wall. Aneurysm rupture has a high mortality risk. Since only a small fracture of aneurysms rupture, and common treatments have their own risks, it is desirable to identify a useful means of assessing rupture risk. Therefore, numerous groups have endeavored to identify a correlation between rupture risk and sac geometry or flow dynamics. However, no clinically useful parameters have been identified to date. Prior work has suggested that the aspect ratio (sac height/neck) could be useful for risk stratification due to its influence on the sac hemodynamics. In this work, we make of a previously developed parametric model of the aneurysm geometry to evaluate the influence of aspect ratio (sac height/sac neck) on flow dynamics, using computational fluid dynamics. In particular, we assess the influence of aspect ratio on the number of vortices in the aneurysm sac over a wide range of sac geometries. The conclusions obtained for the parametric model are then assessed in 20 clinical cases.

  6. Time-frequency analysis for parametric and non-parametric identification of nonlinear dynamical systems

    NASA Astrophysics Data System (ADS)

    Frank Pai, P.

    2013-04-01

    This paper points out the differences between linear and nonlinear system identification tasks, shows that time-frequency analysis is most appropriate for nonlinearity identification, and presents advanced signal processing techniques that combine time-frequency decomposition and perturbation methods for parametric and non-parametric identification of nonlinear dynamical systems. Hilbert-Huang transform (HHT) is a recent data-driven adaptive time-frequency analysis technique that combines the use of empirical mode decomposition (EMD) and Hilbert transform (HT). Because EMD does not use predetermined basis functions and function orthogonality for component extraction, HHT provides more concise component decomposition and more accurate time-frequency analysis than the short-time Fourier transform and wavelet transform for extraction of system characteristics and nonlinearities. However, HHT's accuracy seriously suffers from the end effect caused by the discontinuity-induced Gibbs' phenomenon. Moreover, because HHT requires a long set of data obtained by high-frequency sampling, it is not appropriate for online frequency tracking. This paper presents a conjugate-pair decomposition (CPD) method that requires only a few recent data points sampled at a low-frequency for sliding-window point-by-point adaptive time-frequency analysis and can be used for online frequency tracking. To improve adaptive time-frequency analysis, a methodology is developed by combining EMD and CPD for noise filtering in the time domain, reducing the end effect, and dissolving other mathematical and numerical problems in time-frequency analysis. For parametric identification of a nonlinear system, the methodology processes one steady-state response and/or one free damped transient response and uses amplitude-dependent dynamic characteristics derived from perturbation analysis to determine the type and order of nonlinearity and system parameters. For non-parametric identification, the methodology

  7. Examining Perception of Competency through Practicum Competencies Outline

    ERIC Educational Resources Information Center

    Esposito, Giovanna; Freda, Maria Francesca; Bosco, Valentina

    2015-01-01

    Purpose: This study aims to examine the self-perceived competencies of 231 Italian students enrolled in a psychological degree program and involved in a practicum. It analyzes the subjective perception of the competences that students expect to develop, acknowledge as developed and that might be inferred from tasks performed during the practicum;…

  8. Building Intercultural Competence through Intercultural Competency Certification of Undergraduate Students

    ERIC Educational Resources Information Center

    Janeiro, Maria G. Fabregas; Fabre, Ricardo Lopez; Nuno de la Parra, Jose Pablo

    2014-01-01

    The Intercultural Competency Certificate (CCI in Spanish) designed for the Universidad Popular Autonoma del Estado de Puebla (UPAEP University) is a theory based comprehensive plan to develop undergraduate students' intercultural competence. This Certificate is based in the Developmental Model of Intercultural Sensitivity (DMIS) developed by…

  9. Competencies: The Competencies Debate in Australian Education and Training.

    ERIC Educational Resources Information Center

    Collins, Cherry, Ed.

    Competencies are the focal concept in the world of education and training in Australia at this moment in 1993. This book is a collection of papers and has three purposes. First, it aims to provide basic information about education and training. Second, the book aims to explore something of what competency-based education and training looks like in…

  10. Where Cultural Competency Begins: Changes in Undergraduate Students' Intercultural Competency

    ERIC Educational Resources Information Center

    Sandell, Elizabeth J.; Tupy, Samantha J.

    2015-01-01

    Teacher preparation programs and accreditation organizations have acknowledged need for educators to demonstrate intercultural knowledge, skills, and abilities. Teacher educators are responding to emphasis in higher education to assure that graduates achieve intercultural competence (NCATE, 2008). This study compared the cultural competency of…

  11. Competence and Competency-based Training: What the Literature Says

    ERIC Educational Resources Information Center

    Guthrie, Hugh

    2009-01-01

    This literature review, commissioned by the National Quality Council, provides a historical account of the development of competency-based training in Australia and summarises the issues arising from the range of reviews conducted on elements of the national training system. It also explores the variety of ways in which competence is conceived…

  12. Eating Competence: Nutrition Education with the Satter Eating Competence Model

    ERIC Educational Resources Information Center

    Satter, Ellyn

    2007-01-01

    The Satter Eating Competence Model (ecSatter) conceptualizes eating competence as having 4 components: eating attitudes, food acceptance, regulation of food intake and body weight, and management of the eating context (including family meals). According to ecSatter, supporting nutritional health requires establishing and maintaining positive…

  13. Competing on talent analytics.

    PubMed

    Davenport, Thomas H; Harris, Jeanne; Shapiro, Jeremy

    2010-10-01

    Do investments in your employees actually affect workforce performance? Who are your top performers? How can you empower and motivate other employees to excel? Leading-edge companies such as Google, Best Buy, Procter & Gamble, and Sysco use sophisticated data-collection technology and analysis to answer these questions, leveraging a range of analytics to improve the way they attract and retain talent, connect their employee data to business performance, differentiate themselves from competitors, and more. The authors present the six key ways in which companies track, analyze, and use data about their people-ranging from a simple baseline of metrics to monitor the organization's overall health to custom modeling for predicting future head count depending on various "what if" scenarios. They go on to show that companies competing on talent analytics manage data and technology at an enterprise level, support what analytical leaders do, choose realistic targets for analysis, and hire analysts with strong interpersonal skills as well as broad expertise.

  14. Competing on analytics.

    PubMed

    Davenport, Thomas H

    2006-01-01

    We all know the power of the killer app. It's not just a support tool; it's a strategic weapon. Companies questing for killer apps generally focus all their firepower on the one area that promises to create the greatest competitive advantage. But a new breed of organization has upped the stakes: Amazon, Harrah's, Capital One, and the Boston Red Sox have all dominated their fields by deploying industrial-strength analytics across a wide variety of activities. At a time when firms in many industries offer similar products and use comparable technologies, business processes are among the few remaining points of differentiation--and analytics competitors wring every last drop of value from those processes. Employees hired for their expertise with numbers or trained to recognize their importance are armed with the best evidence and the best quantitative tools. As a result, they make the best decisions. In companies that compete on analytics, senior executives make it clear--from the top down--that analytics is central to strategy. Such organizations launch multiple initiatives involving complex data and statistical analysis, and quantitative activity is managed atthe enterprise (not departmental) level. In this article, professor Thomas H. Davenport lays out the characteristics and practices of these statistical masters and describes some of the very substantial changes other companies must undergo in order to compete on quantitative turf. As one would expect, the transformation requires a significant investment in technology, the accumulation of massive stores of data, and the formulation of company-wide strategies for managing the data. But, at least as important, it also requires executives' vocal, unswerving commitment and willingness to change the way employees think, work, and are treated.

  15. 3D simulation of parametric ultrasound fields

    NASA Astrophysics Data System (ADS)

    Prieur, Fabrice

    2012-09-01

    Parametric sonar is widely used for seafloor characterization, sub-bottom object detection, or underwater communication. It takes advantage of the interaction between two primary beams transmitted at slightly different frequencies. Due to nonlinear propagation, two secondary beams at the sum and difference frequency are generated. The signal at the difference frequency combines sub-bottom penetration due to low attenuation, and high resolution due to an acoustic beam with a narrow mainlobe and negligible sidelobes. A method is presented that provides a full three dimensional estimate for the amplitude of the secondary fields at any depth without the need for stepwise propagation. The method applies to two dimensional transducers of arbitrary geometry and distribution transmitting wideband pulses. The method is limited by the assumption of a quasi-linear propagation in a homogeneous medium. The obtained results in the case of a flat piston transducer compare favorably to previous measurements and numerical estimates from proved methods.

  16. T test as a parametric statistic.

    PubMed

    Kim, Tae Kyun

    2015-12-01

    In statistic tests, the probability distribution of the statistics is important. When samples are drawn from population N (µ, σ(2)) with a sample size of n, the distribution of the sample mean X̄ should be a normal distribution N (µ, σ(2)/n). Under the null hypothesis µ = µ0, the distribution of statistics [Formula: see text] should be standardized as a normal distribution. When the variance of the population is not known, replacement with the sample variance s (2) is possible. In this case, the statistics [Formula: see text] follows a t distribution (n-1 degrees of freedom). An independent-group t test can be carried out for a comparison of means between two independent groups, with a paired t test for paired data. As the t test is a parametric test, samples should meet certain preconditions, such as normality, equal variances and independence.

  17. Ultrafast Airy beam optical parametric oscillator.

    PubMed

    Apurv Chaitanya, N; Kumar, S Chaitanya; Aadhi, A; Samanta, G K; Ebrahim-Zadeh, M

    2016-01-01

    We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm.

  18. Spontaneous parametric fluorescence in SOI integrated micoresonators

    NASA Astrophysics Data System (ADS)

    Azzini, Stefano; Grassani, Davide; Liscidini, Marco; Galli, Matteo; Gerace, Dario; Sorel, Marc; Strain, Michael J.; Velha, Philippe; Bajoni, Daniele

    2013-10-01

    Four-wave mixing can be stimulated or occur spontaneously: the latter effect, also known as parametric fluorescence, can be explained only in the framework of a quantum theory of light, and it is at the basis of many protocols to generate nonclassical states of the electromagnetic field. In this work we report on our experimental study of spontaneous four wave mixing in microring resonators and photonic crystal molecules integrated on a silicon on insulator platform. We find that both structures are able to generate signal and idler beams in the telecom band, at rates of millions of photons per second, under sub-mW pumping. By comparing the experiments on the two structures we find that the photonic molecule is an order of magnitude more efficient than the ring resonator, due to the reduced mode volume of the individual resonators.

  19. Ultrafast Airy beam optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Apurv Chaitanya, N.; Kumar, S. Chaitanya; Aadhi, A.; Samanta, G. K.; Ebrahim-Zadeh, M.

    2016-08-01

    We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm.

  20. Stellar parametrization from Gaia RVS spectra

    NASA Astrophysics Data System (ADS)

    Recio-Blanco, A.; de Laverny, P.; Allende Prieto, C.; Fustes, D.; Manteiga, M.; Arcay, B.; Bijaoui, A.; Dafonte, C.; Ordenovic, C.; Ordoñez Blanco, D.

    2016-01-01

    Context. Among the myriad of data collected by the ESA Gaia satellite, about 150 million spectra will be delivered by the Radial Velocity Spectrometer (RVS) for stars as faint as GRVS~ 16. A specific stellar parametrization will be performed on most of these RVS spectra, i.e. those with enough high signal-to-noise ratio (S/N), which should correspond to single stars that have a magnitude in the RVS band brighter than ~14.5. Some individual chemical abundances will also be estimated for the brightest targets. Aims: We describe the different parametrization codes that have been specifically developed or adapted for RVS spectra within the GSP-Spec working group of the analysis consortium. The tested codes are based on optimisation (FERRE and GAUGUIN), projection (MATISSE), or pattern-recognition methods (Artificial Neural Networks). We present and discuss each of their expected performances in the recovered stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity) for B- to K-type stars. The performances for determining of [α/Fe] ratios are also presented for cool stars. Methods: Each code has been homogeneously tested with a large grid of RVS simulated synthetic spectra of BAFGK-spectral types (dwarfs and giants), with metallicities varying from 10-2.5 to 10+ 0.5 the solar metallicity, and taking variations of ±0.4 dex in the composition of the α-elements into consideration. The tests were performed for S/N ranging from ten to 350. Results: For all the stellar types we considered, stars brighter than GRVS~ 12.5 are very efficiently parametrized by the GSP-Spec pipeline, including reliable estimations of [α/Fe]. Typical internal errors for FGK metal-rich and metal-intermediate stars are around 40 K in Teff, 0.10 dex in log(g), 0.04 dex in [M/H], and 0.03 dex in [α/Fe] at GRVS = 10.3. They degrade to 155 K in Teff, 0.15 dex in log(g), 0.10 dex in [M/H], and 0.1 dex in [α/Fe] at GRVS~ 12. Similar accuracies in Teff and [M/H] are

  1. Parametric design and gridding through relational geometry

    NASA Technical Reports Server (NTRS)

    Letcher, John S., Jr.; Shook, D. Michael

    1995-01-01

    Relational Geometric Synthesis (RGS) is a new logical framework for building up precise definitions of complex geometric models from points, curves, surfaces and solids. RGS achieves unprecedented design flexibility by supporting a rich variety of useful curve and surface entities. During the design process, many qualitative and quantitative relationships between elementary objects may be captured and retained in a data structure equivalent to a directed graph, such that they can be utilized for automatically updating the complete model geometry following changes in the shape or location of an underlying object. Capture of relationships enables many new possibilities for parametric variations and optimization. Examples are given of panelization applications for submarines, sailing yachts, offshore structures, and propellers.

  2. uvmcmcfit: Parametric models to interferometric data fitter

    NASA Astrophysics Data System (ADS)

    Bussmann, Shane; Leung, Tsz Kuk (Daisy); Conley, Alexander

    2016-06-01

    Uvmcmcfit fits parametric models to interferometric data. It is ideally suited to extract the maximum amount of information from marginally resolved observations with interferometers like the Atacama Large Millimeter Array (ALMA), Submillimeter Array (SMA), and Plateau de Bure Interferometer (PdBI). uvmcmcfit uses emcee (ascl:1303.002) to do Markov Chain Monte Carlo (MCMC) and can measure the goodness of fit from visibilities rather than deconvolved images, an advantage when there is strong gravitational lensing and in other situations. uvmcmcfit includes a pure-Python adaptation of Miriad’s (ascl:1106.007) uvmodel task to generate simulated visibilities given observed visibilities and a model image and a simple ray-tracing routine that allows it to account for both strongly lensed systems (where multiple images of the lensed galaxy are detected) and weakly lensed systems (where only a single image of the lensed galaxy is detected).

  3. Spherical parametrization of the Higgs boson candidate.

    PubMed

    Gainer, James S; Lykken, Joseph; Matchev, Konstantin T; Mrenna, Stephen; Park, Myeonghun

    2013-07-26

    The latest results from the ATLAS and CMS experiments at the CERN Large Hadron Collider unequivocally confirm the existence of a resonance X with mass near 125 GeV which could be the Higgs boson of the standard model. Measuring the properties (quantum numbers and couplings) of this resonance is of paramount importance. Initial analyses by the LHC Collaborations disfavor specific alternative benchmark hypotheses, e.g., pure pseudoscalars or gravitons. However, this is just the first step in a long-term program of detailed measurements. We consider the most general set of operators in the decay channels X→ZZ, WW, Zγ, γγ, and derive the constraint implied by the measured rate. This allows us to provide a useful parametrization of the orthogonal independent Higgs coupling degrees of freedom as coordinates on a suitably defined sphere. PMID:23931355

  4. Turbulent expansion during parametric plasma heating

    NASA Astrophysics Data System (ADS)

    Trakhtengerts, V. Iu.

    1983-10-01

    In recent experiments on the parametric heating of the ionosphere, the application of intense electromagnetic radiation in the shortwave range to the ionospheric F layer has been accompanied by comparatively broad-band stimulated radio emission with a central frequency near the frequency of the pump wave. This emission is thought to result from the conversion of plasma waves into electromagnetic radiation during the three-wave interaction with the ion probe, and is observed even after the pump is turned off. Suprathermal electrons accelerated to 25-30 eV have been observed simultaneously. The anomalously long lifetime of the stimulated emission is explained here in terms of the turbulent expansion of a cloud of suprathermal particles in a collisionless plasma.

  5. Hybrid-free Josephson Parametric Converter

    NASA Astrophysics Data System (ADS)

    Frattini, N. E.; Narla, A.; Sliwa, K. M.; Shankar, S.; Hatridge, M.; Devoret, M. H.

    A necessary component for any quantum computation architecture is the ability to perform efficient quantum operations. In the microwave regime of superconducting qubits, these quantum-limited operations can be realized with a non-degenerate Josephson junction based three-wave mixer, the Josephson Parametric Converter (JPC). Currently, the quantum signal of interest must pass through a lossy 180 degree hybrid to be presented as a differential drive to the JPC. This hybrid therefore places a limit on the quantum efficiency of the system and also increases the device footprint. We present a new design for the JPC eliminating the need for any external hybrid. We also show that this design has nominally identical performance to the conventional JPC. Work supported by ARO, AFOSR and YINQE.

  6. Simplifying the circuit of Josephson parametric converters

    NASA Astrophysics Data System (ADS)

    Abdo, Baleegh; Brink, Markus; Chavez-Garcia, Jose; Keefe, George

    Josephson parametric converters (JPCs) are quantum-limited three-wave mixing devices that can play various important roles in quantum information processing in the microwave domain, including amplification of quantum signals, transduction of quantum information, remote entanglement of qubits, nonreciprocal amplification, and circulation of signals. However, the input-output and biasing circuit of a state-of-the-art JPC consists of bulky components, i.e. two commercial off-chip broadband 180-degree hybrids, four phase-matched short coax cables, and one superconducting magnetic coil. Such bulky hardware significantly hinders the integration of JPCs in scalable quantum computing architectures. In my talk, I will present ideas on how to simplify the JPC circuit and show preliminary experimental results

  7. PARSEC: PARametrized Simulation Engine for Cosmic rays

    NASA Astrophysics Data System (ADS)

    Bretz, Hans-Peter; Erdmann, Martin; Schiffer, Peter; Walz, David; Winchen, Tobias

    2015-02-01

    PARSEC (PARametrized Simulation Engine for Cosmic rays) is a simulation engine for fast generation of ultra-high energy cosmic ray data based on parameterizations of common assumptions of UHECR origin and propagation. Implemented are deflections in unstructured turbulent extragalactic fields, energy losses for protons due to photo-pion production and electron-pair production, as well as effects from the expansion of the universe. Additionally, a simple model to estimate propagation effects from iron nuclei is included. Deflections in the Galactic magnetic field are included using a matrix approach with precalculated lenses generated from backtracked cosmic rays. The PARSEC program is based on object oriented programming paradigms enabling users to extend the implemented models and is steerable with a graphical user interface.

  8. Ultrafast Airy beam optical parametric oscillator

    PubMed Central

    Apurv Chaitanya, N.; Kumar, S. Chaitanya; Aadhi, A.; Samanta, G. K.; Ebrahim-Zadeh, M.

    2016-01-01

    We report on the first realization of an ultrafast Airy beam optical parametric oscillator (OPO). By introducing intracavity cubic phase modulation to the resonant Gaussian signal in a synchronously-pumped singly-resonant OPO cavity and its subsequent Fourier transformation, we have generated 2-dimensional Airy beam in the output signal across a 250 nm tuning range in the near-infrared. The generated Airy beam can be tuned continuously from 1477 to 1727 nm, providing an average power of as much as 306 mW at 1632 nm in pulses of ~23 ps duration with a spectral bandwidth of 1.7 nm. PMID:27476910

  9. Multidimensional Scaling Visualization Using Parametric Entropy

    NASA Astrophysics Data System (ADS)

    Lopes, António M.; Tenreiro Machado, J. A.; Galhano, Alexandra M.

    2015-12-01

    This paper studies complex systems using a generalized multidimensional scaling (MDS) technique. Complex systems are characterized by time-series responses, interpreted as a manifestation of their dynamics. Two types of time-series are analyzed, namely 18 stock markets and the gross domestic product per capita of 18 countries. For constructing the MDS charts, indices based on parametric entropies are adopted. Multiparameter entropies allow the variation of the parameters leading to alternative sets of charts. The final MDS maps are then assembled by means of Procrustes’ method that maximizes the fit between the individual charts. Therefore, the proposed method can be interpreted as a generalization to higher dimensions of the standard technique that represents (and discretizes) items by means of single “points” (i.e. zero-dimensional “objects”). The MDS plots, involving one-, two- and three-dimensional “objects”, reveal a good performance in capturing the correlations between data.

  10. Parametric systems analysis for tandem mirror hybrids

    SciTech Connect

    Lee, J.D.; Chapin, D.L.; Chi, J.W.H.

    1980-09-01

    Fusion fission systems, consisting of fissile producing fusion hybrids combining a tandem mirror fusion driver with various blanket types and net fissile consuming LWR's, have been modeled and analyzed parametrically. Analysis to date indicates that hybrids can be competitive with mined uranium when U/sub 3/O/sub 8/ cost is about 100 $/lb., adding less than 25% to present day cost of power from LWR's. Of the three blanket types considered, uranium fast fission (UFF), thorium fast fission (ThFF), and thorium fission supressed (ThFS), the ThFS blanket has a modest economic advantage under most conditions but has higher support ratios and potential safety advantages under all conditions.

  11. Normal dispersion femtosecond fiber optical parametric oscillator.

    PubMed

    Nguyen, T N; Kieu, K; Maslov, A V; Miyawaki, M; Peyghambarian, N

    2013-09-15

    We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60  mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3  ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths.

  12. Normal dispersion femtosecond fiber optical parametric oscillator.

    PubMed

    Nguyen, T N; Kieu, K; Maslov, A V; Miyawaki, M; Peyghambarian, N

    2013-09-15

    We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60  mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3  ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths. PMID:24104828

  13. Parametric study of double cellular detonation structure

    NASA Astrophysics Data System (ADS)

    Khasainov, B.; Virot, F.; Presles, H.-N.; Desbordes, D.

    2013-05-01

    A parametric numerical study is performed of a detonation cellular structure in a model gaseous explosive mixture whose decomposition occurs in two successive exothermic reaction steps with markedly different characteristic times. Kinetic and energetic parameters of both reactions are varied in a wide range in the case of one-dimensional steady and two-dimensional (2D) quasi-steady self-supported detonations. The range of governing parameters of both exothermic steps is defined where a "marked" double cellular structure exists. It is shown that the two-level cellular structure is completely governed by the kinetic parameters and the local overdrive ratio of the detonation front propagating inside large cells. Furthermore, since it is quite cumbersome to use detailed chemical kinetics in unsteady 2D case, the proposed work should help to identify the mixtures and the domain of their equivalence ratio where double detonation structure could be observed.

  14. Compact, flexible, frequency agile parametric wavelength converter

    DOEpatents

    Velsko, Stephan P.; Yang, Steven T.

    2002-01-01

    This improved Frequency Agile Optical Parametric Oscillator provides near on-axis pumping of a single QPMC with a tilted periodically poled grating to overcome the necessity to find a particular crystal that will permit collinear birefringence in order to obtain a desired tuning range. A tilted grating design and the elongation of the transverse profile of the pump beam in the angle tuning plane of the FA-OPO reduces the rate of change of the overlap between the pumped volume in the crystal and the resonated and non-resonated wave mode volumes as the pump beam angle is changed. A folded mirror set relays the pivot point for beam steering from a beam deflector to the center of the FA-OPO crystal. This reduces the footprint of the device by as much as a factor of two over that obtained when using the refractive telescope design.

  15. Parametric excitation of whistler waves by HF heater

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Lee, M. C.

    1989-01-01

    Possible generation of whistler waves by Tromso HF heater is investigated. It is shown that the HF heater wave can parametrically decay into a whistler wave and a Langmuir wave. Since whistler waves may have a broad range of frequency, the simultaneously excited Langmuir waves can have a much broader frequency bandwidth than those excited by the parametric decay instability.

  16. Tuneable, non-degenerated, nonlinear, parametrically-excited amplifier

    NASA Astrophysics Data System (ADS)

    Dolev, Amit; Bucher, Izhak

    2016-01-01

    The proposed parametric amplifier scheme can be tuned to amplify a wide range of input frequencies by altering the parametric excitation with no need to physically modify the oscillator. Parametric amplifiers had been studied extensively, although most of the work focused on amplifiers that are parametrically excited at a frequency twice the amplifier's natural frequency. These amplifiers are confined to amplifying predetermined frequencies. The proposed parametric amplifier's bandwidth is indeed tuneable to nearly any input frequency, not bound to be an integer multiple of a natural frequency. In order to tune the stiffness and induce a variable frequency parametric excitation, a digitally controlled electromechanical element must be incorporated in the realization. We introduce a novel parametric amplifier with nonlinearity, Duffing type hardening, that bounds the otherwise unlimited amplitude. Moreover, we present a multi degree of freedom system in which a utilization of the proposed method enables the projection of low frequency vector forces on any eigenvector and corresponding natural frequency of the system, and thus to transform external excitations to a frequency band where signal levels are considerably higher. Using the method of multiple scales, analytical expressions for the responses have been retrieved and verified numerically. Parametric studies of the amplifiers' gain, sensitivities and spatial projection of the excitation on the system eigenvectors were carried out analytically. The results demonstrate the advantage of the proposed approach over existing schemes. Practical applications envisaged for the proposed method will be outlined.

  17. Using a Parametric Solid Modeler as an Instructional Tool

    ERIC Educational Resources Information Center

    Devine, Kevin L.

    2008-01-01

    This paper presents the results of a quasi-experimental study that brought 3D constraint-based parametric solid modeling technology into the high school mathematics classroom. This study used two intact groups; a control group and an experimental group, to measure the extent to which using a parametric solid modeler during instruction affects…

  18. Injection-seeded optical parametric oscillator and system

    DOEpatents

    Lucht, Robert P.; Kulatilaka, Waruna D.; Anderson, Thomas N.; Bougher, Thomas L.

    2007-10-09

    Optical parametric oscillators (OPO) and systems are provided. The OPO has a non-linear optical material located between two optical elements where the product of the reflection coefficients of the optical elements are higher at the output wavelength than at either the pump or idler wavelength. The OPO output may be amplified using an additional optical parametric amplifier (OPA) stage.

  19. Parametrization of the SCC-DFTB Method for Halogens.

    PubMed

    Kubař, Tomáš; Bodrog, Zoltán; Gaus, Michael; Köhler, Christof; Aradi, Bálint; Frauenheim, Thomas; Elstner, Marcus

    2013-07-01

    Parametrization of the approximative DFT method SCC-DFTB for halogen elements is presented. The new parameter set is intended to describe halogenated organic as well as inorganic molecules, and it is compatible with the established parametrization of SCC-DFTB for carbon, hydrogen, oxygen, and nitrogen. The performance of the parameter set is tested on a representative set of molecules and discussed.

  20. Parametric cost estimation for space science missions

    NASA Astrophysics Data System (ADS)

    Lillie, Charles F.; Thompson, Bruce E.

    2008-07-01

    Cost estimation for space science missions is critically important in budgeting for successful missions. The process requires consideration of a number of parameters, where many of the values are only known to a limited accuracy. The results of cost estimation are not perfect, but must be calculated and compared with the estimates that the government uses for budgeting purposes. Uncertainties in the input parameters result from evolving requirements for missions that are typically the "first of a kind" with "state-of-the-art" instruments and new spacecraft and payload technologies that make it difficult to base estimates on the cost histories of previous missions. Even the cost of heritage avionics is uncertain due to parts obsolescence and the resulting redesign work. Through experience and use of industry best practices developed in participation with the Aerospace Industries Association (AIA), Northrop Grumman has developed a parametric modeling approach that can provide a reasonably accurate cost range and most probable cost for future space missions. During the initial mission phases, the approach uses mass- and powerbased cost estimating relationships (CER)'s developed with historical data from previous missions. In later mission phases, when the mission requirements are better defined, these estimates are updated with vendor's bids and "bottoms- up", "grass-roots" material and labor cost estimates based on detailed schedules and assigned tasks. In this paper we describe how we develop our CER's for parametric cost estimation and how they can be applied to estimate the costs for future space science missions like those presented to the Astronomy & Astrophysics Decadal Survey Study Committees.

  1. Quantum analysis of optical parametric fluorescence in the optical parametric amplification process

    NASA Astrophysics Data System (ADS)

    Wang, Bopeng; Zou, Xubo; Jing, Feng

    2015-07-01

    The temporal contrast of the ultra-intense laser pulse can be degraded by optical parametric fluorescence (OPF) in high-gain and pulse-pumped optical parametric amplification (OPA). However, to the best of our knowledge, no theory is proposed to describe the quantum noise in such conditions from the first principle. In this paper, we propose a theory based on the quantization of energy flux and a linearization method for investigating both lasers and the OPF in high-gain and pulse-pumped OPA. Following the proposal, the amplification of laser is consistent with classical nonlinear optics. Moreover, an analytical formula of OPF energy is obtained under undepleted and quasi-monochromatic pump conditions. A simplified formula is also obtained under the assumption of small spectral width and acceptant solid angle. Furthermore, a formula of the OPF duration is obtained with a Gaussian pump pulse. Excellent consistency is achieved between previous experiments and our theory.

  2. EI competencies as a related but different characteristic than intelligence

    PubMed Central

    Boyatzis, Richard E.; Batista-Foguet, Joan M.; Fernández-i-Marín, Xavier; Truninger, Margarida

    2015-01-01

    Amid the swarm of debate about emotional intelligence (EI) among academics are claims that cognitive intelligence, or general mental ability (g), is a stronger predictor of life and work outcomes as well as the counter claims that EI is their strongest predictor. Nested within the tempest in a teapot are scientific questions as to what the relationship is between g and EI. Using a behavioral approach to EI, we examined the relationship of a parametric measure of g as the person’s GMAT scores and collected observations from others who live and work with the person as to the frequency of his or her EI behavior, as well as the person’s self-assessment. The results show that EI, as seen by others, is slightly related to g, especially for males with assessment from professional relations. Further, we found that cognitive competencies are more strongly related to GMAT than EI competencies. For observations from personal relationships or self-assessment, there is no relationship between EI and GMAT. Observations from professional relations reveal a positive relationship between cognitive competencies and GMAT and EI and GMAT for males, but a negative relationship between EI and GMAT for females. PMID:25713545

  3. EI competencies as a related but different characteristic than intelligence.

    PubMed

    Boyatzis, Richard E; Batista-Foguet, Joan M; Fernández-I-Marín, Xavier; Truninger, Margarida

    2015-01-01

    Amid the swarm of debate about emotional intelligence (EI) among academics are claims that cognitive intelligence, or general mental ability (g), is a stronger predictor of life and work outcomes as well as the counter claims that EI is their strongest predictor. Nested within the tempest in a teapot are scientific questions as to what the relationship is between g and EI. Using a behavioral approach to EI, we examined the relationship of a parametric measure of g as the person's GMAT scores and collected observations from others who live and work with the person as to the frequency of his or her EI behavior, as well as the person's self-assessment. The results show that EI, as seen by others, is slightly related to g, especially for males with assessment from professional relations. Further, we found that cognitive competencies are more strongly related to GMAT than EI competencies. For observations from personal relationships or self-assessment, there is no relationship between EI and GMAT. Observations from professional relations reveal a positive relationship between cognitive competencies and GMAT and EI and GMAT for males, but a negative relationship between EI and GMAT for females. PMID:25713545

  4. Assessing Competence in Pediatric Cardiology

    ERIC Educational Resources Information Center

    Johnson, Apul E.; And Others

    1976-01-01

    In response to the need to assure physician competence, a rating scale was developed at the University of Minnesota Medical School for use in evaluating clinical competence in pediatric cardiology. It was tested on first- and second-year specialists. Development and testing procedures are described. (JT)

  5. Social Competence: A Developmental Perspective.

    ERIC Educational Resources Information Center

    Eisenberg, Nancy; Harris, Jerry D.

    1984-01-01

    Effective peer relations and the enhancement of social interactions in young children play a central role in the discussion of social competence. Developmental issues relevant to the assessment of social competence including perspective taking, conceptions of friendship, interpersonal strategies and problem solving, moral judgments, and…

  6. Masonry. Occupational Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Occupational Competency Analysis Profile (OCAP) for masonry occupations contains a competency list verified by expert workers and developed through a modified DACUM (Developing a Curriculum) involving business, industry, labor, and community agency representatives from Ohio. This OCAP identifies the occupational, academic, and employability…

  7. Cultural Competency as Skilled Dialogue.

    ERIC Educational Resources Information Center

    Barrera, Isaura; Corso, Robert M.

    2002-01-01

    This article describes Skilled Dialogue, an approach to cultural competency developed in response to the challenges posed by cultural linguistic diversity. Skilled Dialogue focuses on cultural competency as the ability to craft respectful, reciprocal, and responsive interactions across diverse cultural parameters. Characteristics, component…

  8. Competence: Commodification of Human Ability

    ERIC Educational Resources Information Center

    Han, Soonghee

    2008-01-01

    The purpose of this article is to analyze the meaning and presumptions of competence in the concrete context of knowledge capitalism. First, the nature of competence as a "commodification of human ability" that obtains a standardized monetary value to sell in the labor market, is elucidated by applying Karl Marx's critical theory. Second, it is…

  9. Workforce Readiness: Competencies and Assessment.

    ERIC Educational Resources Information Center

    O'Neil, Harold F., Jr., Ed.

    This book, which is intended for professionals in the assessment/evaluation/measurement, vocational and technical education, and educational psychology communities, contains 16 papers examining specifications of work force competencies and assessment of competencies. The following papers are included: "Review of Workforce Readiness Theoretical…

  10. Conversational Competence in Academic Settings

    ERIC Educational Resources Information Center

    Bowman, Richard F.

    2014-01-01

    Conversational competence is a process, not a state. Ithaca does not exist, only the voyage to Ithaca. Vibrant campuses are a series of productive conversations. At its core, communicative competence in academic settings mirrors a collective search for meaning regarding the purpose and direction of a campus community. Communicative competence…

  11. Conditions for Developing Communicative Competence

    ERIC Educational Resources Information Center

    Zascerinska, Jelena

    2010-01-01

    Introduction. Individuals need communicative competence for personal fulfillment and development, active citizenship, social inclusion and employment. Materials and Methods. The meaning of the key concepts of "communicative competence" and "opportunities" is studied within the search for conditions to develop. Conclusion. The theoretical findings…

  12. Youth Swimmers' Understanding of Competence.

    ERIC Educational Resources Information Center

    Bocksnick, Jochen; Belyk, Joi; Napier, Linea

    2002-01-01

    Investigated the way in which youth swimmers viewed their competence and factors they associated with obtaining competence. Interviews with Canadian swimmers age 8-13 years indicated that respondents focused on what they deemed performance-relevant factors (e.g., personal effort) rather than outcome-related comparisons with other swimmers (e.g.,…

  13. Ensuring Competency in Health Professions.

    ERIC Educational Resources Information Center

    Baker, Shirley Ann

    1986-01-01

    Reports that vocational health occupations programs are undergoing a self-analysis process including evaluation of competency and continuing competency. Presents perspectives of health professionals with comparisons to nursing and medical technology credentialing and continuing education. These perspectives are intended for other occupational…

  14. Horticulture. Tech Prep Competency Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Wooster. Agricultural Technical Inst.

    This tech prep competency profile (TCP), which was developed by a consortium of Ohio educators and business/industry representatives, lists the competencies that have been identified as necessary for employment in the following occupations: nursery technician; golf course superintendent; landscape designer/manager; lawn care specialist; tree care…

  15. Competencies Identification for Robotics Training.

    ERIC Educational Resources Information Center

    Tang, Le D.

    A study focused on the task of identifying competencies for robotics training. The level of robotics training was limited to that of robot technicians. Study objectives were to obtain a list of occupational competencies; to rank their order of importance; and to compare opinions from robot manufacturers, robot users, and robotics educators…

  16. Cultural competency training in psychiatry.

    PubMed

    Qureshi, A; Collazos, F; Ramos, M; Casas, M

    2008-01-01

    Recent reports indicate that the quality of care provided to immigrant and ethnic minority patients is not at the same level as that provided to majority group patients. Although the European Board of Medical Specialists recognizes awareness of cultural issues as a core component of the psychiatry specialization, few medical schools provide training in cultural issues. Cultural competence represents a comprehensive response to the mental health care needs of immigrant and ethnic minority patients. Cultural competence training involves the development of knowledge, skills, and attitudes that can improve the effectiveness of psychiatric treatment. Cognitive cultural competence involves awareness of the various ways in which culture, immigration status, and race impact psychosocial development, psychopathology, and therapeutic transactions. Technical cultural competence involves the application of cognitive cultural competence, and requires proficiency in intercultural communication, the capacity to develop a therapeutic relationship with a culturally different patient, and the ability to adapt diagnosis and treatment in response to cultural difference. Perhaps the greatest challenge in cultural competence training involves the development of attitudinal competence inasmuch as it requires exploration of cultural and racial preconceptions. Although research is in its infancy, there are increasing indications that cultural competence can improve key aspects of the psychiatric treatment of immigrant and minority group patients. PMID:18371580

  17. Holistic Competence: Putting Judgements First

    ERIC Educational Resources Information Center

    Beckett, David

    2008-01-01

    Professional practice can be conceptualised holistically, and in fact during the 1990s the "Australian model" of integrated or holistic competence emerged empirically. This piece outlines that story, and then develops a more rigorous conceptual analysis of what it is to make competent practical judgements, through inferences, in context-specific…

  18. Receptionist: Task List Competency Record.

    ERIC Educational Resources Information Center

    Minnesota Instructional Materials Center, White Bear Lake.

    One of a series of 12 in the secretarial/clerical area, this booklet for the vocational instructor contains a job description for the receptionist, a task list of areas of competency, an occupational tasks competency record (suggested as replacement for the traditional report card), a list of industry representatives and educators involved in…

  19. The Culturally Competent Art Educator.

    ERIC Educational Resources Information Center

    Andrus, Lucy

    2001-01-01

    Focuses on the importance of preparing teachers to be culturally competent art educators, addresses the qualities of a culturally competent teacher, delineates Mazrui's seven functions of culture, and explores how to comprehend multicultural practice. Discusses how teachers can acquire cultural knowledge through literature, films and videos, and…

  20. Experience, Competence and Workplace Learning

    ERIC Educational Resources Information Center

    Paloniemi, Susanna

    2006-01-01

    Purpose: This paper aims to examine employees' conceptions of the meaning of experience in job-competence and its development in workplace context. The aim is to bring out the variety of conceptions related to experience, competence and workplace learning. Design/methodology/approach: The paper is based on interview data from six Finnish small and…

  1. Caveat on Competency Based Education.

    ERIC Educational Resources Information Center

    Bell, Wendell D.

    1980-01-01

    Although competency based education (CBE) offers solutions to some educational problems, it is not a cure-all. Problems with CBE include emphasis on output rather than the instructional process itself, over-reliance on occupational competencies and behavioral objectives, a tendency to lower academic standards, and the difficulty of implementation.…

  2. Personal Competencies in Personalized Learning

    ERIC Educational Resources Information Center

    Redding, Sam

    2014-01-01

    Personal competencies--cognitive, metacognitive, motivational, and social/emotional--are applied by students in learning (mastery of knowledge and skills). These competencies are both acquired through learning and applied in the learning process. Personalized learning--a promising approach to education made practical by advances in…

  3. Competency Assessment and Continuing Education.

    ERIC Educational Resources Information Center

    Schlegel, John F.

    1978-01-01

    Described is the competency project being conducted by the American Association of Colleges of Pharmacy and the American Pharmaceutical Association, and its relationship to the development of continuing education programs. The project is attempting to specify standards of competency and develop self-assessment devices to be used by pharmacists.…

  4. Drafting. Occupational Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Drafting Occupational Competency Analysis Profile (OCAP) is one of a series of competency lists, verified by expert workers, that have evolved from a modified DACUM (Developing a Curriculum) job analysis process involving business, industry, labor, and community agency representatives from throughout Ohio. This OCAP identifies the…

  5. Key Skills and Competencies. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers on key skills and competencies and human resource development (HRD). "Career Related Competencies" (Marinka A.C.T. Kuijpers) reports findings from surveys completed by Dutch employees who identified these issues: self-reflection is more important than career control; age and gender influence attitude toward…

  6. Career Competencies for Career Success

    ERIC Educational Resources Information Center

    Kuijpers, Marinka A. C. T.; Schyns, Birgit; Scheerens, Jaap

    2006-01-01

    This article addresses the general question as to which competencies employees need to possess in order to engage in self-management in their career development. The authors distinguished and operationalized 6 career factors and competencies of self-management in career development. A quantitative study was performed using 1,579 employees in 16…

  7. A Taxonomy for Competency Programs.

    ERIC Educational Resources Information Center

    Finch, F. L.

    To consolidate the diversity of opinion about the definition of competency, an operational definition and skills classification matrix is presented. Although most people agree that competency tests should measure student ability to transfer academic training to life situations, the fact that life skills and school skills represent different…

  8. The Law and Competency Evaluation.

    ERIC Educational Resources Information Center

    Clement, Annie

    Competency testing often refers to a system devised to assure successful performance on a specific test, in addition to other mandated criteria as a requisite to obtaining a high school diploma. Minimum competency testing is usually defined in one of two ways: as the acquisition of basic skills or as the demonstrated ability to apply basic skills…

  9. Cultural competency training in psychiatry.

    PubMed

    Qureshi, A; Collazos, F; Ramos, M; Casas, M

    2008-01-01

    Recent reports indicate that the quality of care provided to immigrant and ethnic minority patients is not at the same level as that provided to majority group patients. Although the European Board of Medical Specialists recognizes awareness of cultural issues as a core component of the psychiatry specialization, few medical schools provide training in cultural issues. Cultural competence represents a comprehensive response to the mental health care needs of immigrant and ethnic minority patients. Cultural competence training involves the development of knowledge, skills, and attitudes that can improve the effectiveness of psychiatric treatment. Cognitive cultural competence involves awareness of the various ways in which culture, immigration status, and race impact psychosocial development, psychopathology, and therapeutic transactions. Technical cultural competence involves the application of cognitive cultural competence, and requires proficiency in intercultural communication, the capacity to develop a therapeutic relationship with a culturally different patient, and the ability to adapt diagnosis and treatment in response to cultural difference. Perhaps the greatest challenge in cultural competence training involves the development of attitudinal competence inasmuch as it requires exploration of cultural and racial preconceptions. Although research is in its infancy, there are increasing indications that cultural competence can improve key aspects of the psychiatric treatment of immigrant and minority group patients.

  10. [Core competencies in internal medicine].

    PubMed

    Porcel, J M; Casademont, J; Conthe, P; Pinilla, B; Pujol, R; García-Alegría, J

    2011-06-01

    The working group of the Spanish Society of Internal Medicine (SEMI) on "Competencies of the Internist" has defined the basic medical knowledge, skills and attitudes that all internists in Spain should have. This list of competencies represents the Internal Medicine core curriculum within the context of the future educational framework of medical specialties in Health Sciences.

  11. Extended parametric representation of compressor fans and turbines. Volume 2: Part user's manual (parametric turbine)

    NASA Technical Reports Server (NTRS)

    Coverse, G. L.

    1984-01-01

    A turbine modeling technique has been developed which will enable the user to obtain consistent and rapid off-design performance from design point input. This technique is applicable to both axial and radial flow turbine with flow sizes ranging from about one pound per second to several hundred pounds per second. The axial flow turbines may or may not include variable geometry in the first stage nozzle. A user-specified option will also permit the calculation of design point cooling flow levels and corresponding changes in efficiency for the axial flow turbines. The modeling technique has been incorporated into a time-sharing program in order to facilitate its use. Because this report contains a description of the input output data, values of typical inputs, and example cases, it is suitable as a user's manual. This report is the second of a three volume set. The titles of the three volumes are as follows: (1) Volume 1 CMGEN USER's Manual (Parametric Compressor Generator); (2) Volume 2 PART USER's Manual (Parametric Turbine); (3) Volume 3 MODFAN USER's Manual (Parametric Modulation Flow Fan).

  12. Scaling of preferential flow in biopores by parametric or non parametric transfer functions

    NASA Astrophysics Data System (ADS)

    Zehe, E.; Hartmann, N.; Klaus, J.; Palm, J.; Schroeder, B.

    2009-04-01

    Rapid flow in connected macropores - often worm burrows or sometimes shrinkage cracks - is today accepted to play a key role for transport of agro chemicals in cohesive soils. Nevertheless, we still struggle to come up with reliable predictions at the field or even the catchment scale, also because crucial information on the spatial distribution of connected subsurface structures is most difficult to access. Assessing the environmental risk of pesticides transport in earthworm burrows requires the development of an integrated eco-hydrological model that allows predictions of a) the spatiotemporal distribution and population dynamics of anecic earthworms, b) the related pattern of connective preferential flow pathways (i.e., earthworm burrows), and c) the space-time pattern of infiltration and travel times distribution of solutes considering short and long term feedbacks. The suggested paper will present the first steps towards this long term goal of the so called BIOPORE project. The first step is to assess statistical data on the spatial distribution of worm burrows in the study area. Deep digging earthworms create mainly vertical semi-permanent burrows of moderate tortuosity down to a depth of 3m (Shipitalo and Butt, 1999). Data on the spatial density of worm burrows and their depth is gathered by preparing horizontal soil profiles (Zehe and Fluehler, 2001). Hydraulic properties of worm burrows are straightforward to measure either by means of a special permeameter (Shipitalo and Butt, 1999) or by taking macroporous samples to the lab. The next step is to establish a link between the distribution of travel depths of a tracer/pesticide that occurs during events and the depth distribution of connected flow paths that link the surface continuously to the subsoils. To this end we generate a population of macropores using a Poisson process for the number of macropores per model element, a normal process compared with an anisotropic random walk for pore lengths and

  13. Nursing informatics competencies: bibliometric analysis.

    PubMed

    Kokol, Peter; Blažun, Helena; Vošner, Janez; Saranto, Kaija

    2014-01-01

    Information and communication technology is developing rapidly and it is incorporated in many health care processes, but in spite of that fact we can still notice that nursing informatics competencies had received limited attention in basic nursing education curricula in Europe and especially in Eastern European countries. The purpose of the present paper is to present the results of a bibliometric analysis of the nursing informatics competencies scientific literature production. We applied the bibliometrics analysis to the corpus of 332 papers found in SCOPUS, related to nursing informatics competencies. The results showed that there is a positive trend in the number of published papers per year, indicating the increased research interest in nursing informatics competencies. Despite the fact that the first paper was published in Denmark, the most prolific country regarding the research in nursing informatics competencies is United States as are their institutions and authors.

  14. Constructivism in cultural competence education.

    PubMed

    Hunter, Jennifer L; Krantz, Steven

    2010-04-01

    A graduate course on cultural diversity, based in constructivist theory and structured on the Process of Cultural Competence in the Delivery of Healthcare Services model, was developed and taught through classroom and online methods. The following research questions were explored: 1) Can an educational experience, built on constructivist learning theory tenets, change students' perceptions, attitudes, knowledge, and skills in the area of cultural competence? 2) Does the delivery method, online or traditional classroom, influence the degree of change? The study used a quasi-experimental, pretest-posttest control group design using the Inventory for Assessing the Process of Cultural Competence Among healthcare Professionals Revised. Findings showed significant changes (p<0.001) in cultural competence scores and subscores for all learners with both teaching modalities based on interval scale and in categories of cultural knowledge, skills, desire, and overall competence based on a nominal scale. The untaught construct of cultural desire showed the most significant improvement.

  15. Cultural competence: a constructivist definition.

    PubMed

    Blanchet Garneau, Amélie; Pepin, Jacinthe

    2015-01-01

    In nursing education, most of the current teaching practices perpetuate an essentialist perspective of culture and make it imperative to refresh the concept of cultural competence in nursing. The purpose of this article is to propose a constructivist definition of cultural competence that stems from the conclusions of an extensive critical review of the literature on the concepts of culture, cultural competence, and cultural safety among nurses and other health professionals. The proposed constructivist definition is situated in the unitary-transformative paradigm in nursing as defined by Newman and colleagues. It makes the connection between the field of competency-based education and the nursing discipline. Cultural competence in a constructivist paradigm that is oriented toward critical, reflective practice can help us develop knowledge about the role of nurses in reducing health inequalities and lead to a comprehensive ethical reflection about the social mandate of health care professionals.

  16. Testing Communicative Competence: Problems and Perspectives.

    ERIC Educational Resources Information Center

    Courchene, Robert J.; De Bagheera, Jean Ivan

    1981-01-01

    A model for communicative competence, developed by Swain and Canale describes four competences within the concept of communicative competence. These are linguistic, sociolinguistic, discourse, and strategic competence. Each one involves knowledge of and ability to use the competence in question. This model raises questions on several counts; for…

  17. 32 CFR 776.20 - Competence.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Competence. 776.20 Section 776.20 National... Professional Conduct § 776.20 Competence. (a) Competence. A covered attorney shall provide competent, diligent.... Initial determinations as to competence of a covered USG attorney for a particular assignment shall...

  18. Lunar lander configuration study and parametric performance analysis

    NASA Technical Reports Server (NTRS)

    Donahue, Benjamin B.; Fowler, C. R.

    1993-01-01

    Future Lunar exploration plans will call for delivery of significant mounts or cargo to provide for crew habitation, surface tansportation, and scientific exploration activities. Minimization of costly surface based infrastructure is in large part directly related to the design of the cargo delivery/landing craft. This study focused on evaluating Lunar lander concepts from a logistics oriented perspective, and outlines the approach used in the development of a preferred configuration, sets forth the benefits derived from its utilization and describes the missions and system considered. Results indicate that only direct-to-surface downloading of payloads provides for unassisted cargo removal operations imperative to efficient and low risk site buildup, including the emplacement of Space Station derivative surface habitat modules, immediate cargo jettison for both descent abort and emergency surface ascent essential to piloted missions carrying cargo, and short habitat egress/ingress paths necessary to productive surface work tours for crew members carrying hand held experiments, tools and other bulky articles. Accommodating cargo in a position underneath the vehicles structural frame, landing craft described herein eliminate altogether the necessity for dedicated surface based off-loading vehicles, the operations and maintenance associated with their operation, and the precipitous ladder climbs to and from the surface that are inherent to traditional designs. Parametric evaluations illustrate performance and mass variation with respect to mission requirements.

  19. Lunar lander configuration study and parametric performance analysis

    NASA Astrophysics Data System (ADS)

    Donahue, Benjamin B.; Fowler, C. R.

    1993-06-01

    Future Lunar exploration plans will call for delivery of significant mounts or cargo to provide for crew habitation, surface tansportation, and scientific exploration activities. Minimization of costly surface based infrastructure is in large part directly related to the design of the cargo delivery/landing craft. This study focused on evaluating Lunar lander concepts from a logistics oriented perspective, and outlines the approach used in the development of a preferred configuration, sets forth the benefits derived from its utilization and describes the missions and system considered. Results indicate that only direct-to-surface downloading of payloads provides for unassisted cargo removal operations imperative to efficient and low risk site buildup, including the emplacement of Space Station derivative surface habitat modules, immediate cargo jettison for both descent abort and emergency surface ascent essential to piloted missions carrying cargo, and short habitat egress/ingress paths necessary to productive surface work tours for crew members carrying hand held experiments, tools and other bulky articles. Accommodating cargo in a position underneath the vehicles structural frame, landing craft described herein eliminate altogether the necessity for dedicated surface based off-loading vehicles, the operations and maintenance associated with their operation, and the precipitous ladder climbs to and from the surface that are inherent to traditional designs. Parametric evaluations illustrate performance and mass variation with respect to mission requirements.

  20. Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)

    SciTech Connect

    Bradley K. Heath

    2014-03-01

    This work supports the restart of transient testing in the United States using the Department of Energy’s Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show that fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuel’s cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISON’s results. BISON’s models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.

  1. Non-parametric extraction of implied asset price distributions

    NASA Astrophysics Data System (ADS)

    Healy, Jerome V.; Dixon, Maurice; Read, Brian J.; Cai, Fang Fang

    2007-08-01

    We present a fully non-parametric method for extracting risk neutral densities (RNDs) from observed option prices. The aim is to obtain a continuous, smooth, monotonic, and convex pricing function that is twice differentiable. Thus, irregularities such as negative probabilities that afflict many existing RND estimation techniques are reduced. Our method employs neural networks to obtain a smoothed pricing function, and a central finite difference approximation to the second derivative to extract the required gradients. This novel technique was successfully applied to a large set of FTSE 100 daily European exercise (ESX) put options data and as an Ansatz to the corresponding set of American exercise (SEI) put options. The results of paired t-tests showed significant differences between RNDs extracted from ESX and SEI option data, reflecting the distorting impact of early exercise possibility for the latter. In particular, the results for skewness and kurtosis suggested different shapes for the RNDs implied by the two types of put options. However, both ESX and SEI data gave an unbiased estimate of the realised FTSE 100 closing prices on the options’ expiration date. We confirmed that estimates of volatility from the RNDs of both types of option were biased estimates of the realised volatility at expiration, but less so than the LIFFE tabulated at-the-money implied volatility.

  2. Using competences and competence tools in workforce development.

    PubMed

    Green, Tess; Dickerson, Claire; Blass, Eddie

    The NHS Knowledge and Skills Framework (KSF) has been a driving force in the move to competence-based workforce development in the NHS. Skills for Health has developed national workforce competences that aim to improve behavioural performance, and in turn increase productivity. This article describes five projects established to test Skills for Health national workforce competences, electronic tools and products in different settings in the NHS. Competences and competence tools were used to redesign services, develop job roles, identify skills gaps and develop learning programmes. Reported benefits of the projects included increased clarity and a structured, consistent and standardized approach to workforce development. Findings from the evaluation of the tools were positive in terms of their overall usefulness and provision of related training/support. Reported constraints of using the competences and tools included issues relating to their availability, content and organization. It is recognized that a highly skilled and flexible workforce is important to the delivery of high-quality health care. These projects suggest that Skills for Health competences can be used as a 'common currency' in workforce development in the UK health sector. This would support the need to adapt rapidly to changing service needs.

  3. Using competences and competence tools in workforce development.

    PubMed

    Green, Tess; Dickerson, Claire; Blass, Eddie

    The NHS Knowledge and Skills Framework (KSF) has been a driving force in the move to competence-based workforce development in the NHS. Skills for Health has developed national workforce competences that aim to improve behavioural performance, and in turn increase productivity. This article describes five projects established to test Skills for Health national workforce competences, electronic tools and products in different settings in the NHS. Competences and competence tools were used to redesign services, develop job roles, identify skills gaps and develop learning programmes. Reported benefits of the projects included increased clarity and a structured, consistent and standardized approach to workforce development. Findings from the evaluation of the tools were positive in terms of their overall usefulness and provision of related training/support. Reported constraints of using the competences and tools included issues relating to their availability, content and organization. It is recognized that a highly skilled and flexible workforce is important to the delivery of high-quality health care. These projects suggest that Skills for Health competences can be used as a 'common currency' in workforce development in the UK health sector. This would support the need to adapt rapidly to changing service needs. PMID:21072016

  4. Comparisons of parametric and non-parametric classification rules for e-nose and e-tongue

    NASA Astrophysics Data System (ADS)

    Mahat, Nor Idayu; Zakaria, Ammar; Shakaff, Ali Yeon Md

    2015-12-01

    This paper evaluates the performance of parametric and non-parametric classification rules in sensor technology. The growing of sensor technologies, e-nose and e-tongue, has urged engineers to equip themselves with the utmost recent and advanced statistical approaches. As data collected from e-nose and e-tongue face some complexities, often data pre-processing and transformation are performed prior to the classification. This paper discusses the comparisons made on some known parametric and non-parametric classification rules in the application for classifying data of e-nose and e-tongue. The comparisons which based on leave-one-out accuracy, sensitivity and specificity shows that non-parametric approaches especially k-nearest neighbour does not much distorted with changes of distribution, but Naïve Bayes is greatly influenced by the structure of the data.

  5. Competencies for the 21st Century Information Professional: Translating the SLA Competencies into Business Competencies.

    ERIC Educational Resources Information Center

    Henczel, Sue

    This paper examines how the Special Libraries Association competencies can be mapped to the broader business competencies of marketing (promoting), packaging (product development), persuading and performing (sales/customer service), and positioning (strategic maneuvering). It introduces a process whereby the skills, knowledge, understandings, and…

  6. Parametric study of prospective early commercial MHD power plants (PSPEC). General Electric Company, task 1: Parametric analysis

    NASA Technical Reports Server (NTRS)

    Marston, C. H.; Alyea, F. N.; Bender, D. J.; Davis, L. K.; Dellinger, T. C.; Hnat, J. G.; Komito, E. H.; Peterson, C. A.; Rogers, D. A.; Roman, A. J.

    1980-01-01

    The performance and cost of moderate technology coal-fired open cycle MHD/steam power plant designs which can be expected to require a shorter development time and have a lower development cost than previously considered mature OCMHD/steam plants were determined. Three base cases were considered: an indirectly-fired high temperature air heater (HTAH) subsystem delivering air at 2700 F, fired by a state of the art atmospheric pressure gasifier, and the HTAH subsystem was deleted and oxygen enrichment was used to obtain requisite MHD combustion temperature. Coal pile to bus bar efficiencies in ease case 1 ranged from 41.4% to 42.9%, and cost of electricity (COE) was highest of the three base cases. For base case 2 the efficiency range was 42.0% to 45.6%, and COE was lowest. For base case 3 the efficiency range was 42.9% to 44.4%, and COE was intermediate. The best parametric cases in bases cases 2 and 3 are recommended for conceptual design. Eventual choice between these approaches is dependent on further evaluation of the tradeoffs among HTAH development risk, O2 plant integration, and further refinements of comparative costs.

  7. Competency courts: a creative solution for restoring competency to the competency process.

    PubMed

    Finkle, Michael J; Kurth, Russell; Cadle, Christopher; Mullan, Jessica

    2009-01-01

    It is well accepted that jail is a poor setting for treating the acutely mentally ill, yet the number of mentally ill persons in jail has increased such that Los Angeles County Jail and Riker's Island in New York house more mentally ill than any psychiatric hospital. The number of mentally ill persons charged with a crime whose competency to stand trial is in question has also increased dramatically. Inefficiencies within the competency process result in mentally ill persons charged with crimes remaining in jail longer than necessary. One solution is "competency court", a specialty court within a mental health court. The same judges, attorneys, and mental health professionals staff both courts. By combining their Mental Health Court experience, they can work with the mentally ill using their expertise in competency law and processes, and thereby improve the competency process and reduce the unnecessary time that mentally ill persons spend in jail.

  8. Associations between Eating Competence and Cardiovascular Disease Biomarkers

    ERIC Educational Resources Information Center

    Psota, Tricia L.; Lohse, Barbara; West, Sheila G.

    2007-01-01

    Objective: Explore the relationship between eating competence (EC) and biomarkers of risk for cardiovascular disease (CVD). Design: Secondary analysis of data collected for a larger, 2-way crossover clinical trial. Setting: Outpatient clinical research center. Participants: Forty-eight hypercholesterolemic (LDL cholesterol [greater than or equal]…

  9. Core Competencies and the Prevention of Adolescent Substance Use

    ERIC Educational Resources Information Center

    Haegerich, Tamara M.; Tolan, Patrick H.

    2008-01-01

    Adolescence is a developmental period during which youth are at increased risk for using substances. An empirical focus on core competencies illustrates that youth are less likely to use substances when they have a positive future orientation, a belief in the ability to resist substances, emotional and behavioral control, sound decision-making…

  10. Building Strength through Enhancing Social Competence in Immigrant Students in Primary School: A Pilot Study

    ERIC Educational Resources Information Center

    Ogden, Terje; Sorlie, Mari-Anne; Hagen, Kristine Amlund

    2007-01-01

    In the present pilot study we examined how a school-wide intervention model, "Positive behavior, interactions and learning environment in school" (Norwegian acronym: PALS) contributed to risk reduction in immigrant students through the promotion of social competence. The aims of the PALS project were to promote social competence through positive…

  11. The Social Competence of Latino Kindergartners and Growth in Mathematical Understanding

    ERIC Educational Resources Information Center

    Galindo, Claudia; Fuller, Bruce

    2010-01-01

    We know that social competence contributes to young children's adaptation to, and cognitive learning within, classroom settings. Yet initial evidence is mixed on the social competencies that Latino children bring to kindergarten and the extent to which these skills advance cognitive growth. Building from ecocultural and developmental-risk theory,…

  12. Models of Emotion Skills and Social Competence in the Head Start Classroom

    ERIC Educational Resources Information Center

    Spritz, Becky L.; Sandberg, Elisabeth Hollister; Maher, Edward; Zajdel, Ruth T.

    2010-01-01

    Research Findings: Fostering the social competence of at-risk preschoolers would be facilitated by knowing which of children's emotion skills are most salient to social outcomes. We examined the emotion skills and social competence of 44 children enrolled in a Head Start program. Emotion skills were examined in terms of children's emotional…

  13. Competency Model 101. The Process of Developing Core Competencies.

    ERIC Educational Resources Information Center

    Eichelberger, Lisa Wright; Hewlett, Peggy O'Neill

    1999-01-01

    The Mississippi Competency Model defines nurses' roles as provider (caregiver, teacher, counselor, advocate), professional (scholar, collaborator, ethicist, researcher), and manager (leader, facilitator, intrapreneur, decision maker, technology user) for four levels of nursing: licensed practical nurse, associate degree, bachelor's degree, and…

  14. Competently assessing competence to stand trial can be trying.

    PubMed

    Akinkunmi, Akintunde A

    2006-01-01

    This brief commentary discusses the difficulties inherent in assessing competency to stand trial (CST), especially when attempting to match the use of instruments with the outcomes of clinical assessment. Suggestions for possible future lines of research are made.

  15. Genetic competence in Bacillus subtilis.

    PubMed Central

    Dubnau, D

    1991-01-01

    Genetic competence may be defined as a physiological state enabling a bacterial culture to bind and take up high-molecular-weight exogenous DNA (transformation). In Bacillus subtilis, competence develops postexponentially and only in certain media. In addition, only a minority of the cells in a competent culture become competent, and these are physiologically distinct. Thus, competence is subject to three regulatory modalities: growth stage specific, nutritionally responsive, and cell type specific. This review summarizes the present state of knowledge concerning competence in B. subtilis. The study of genes required for transformability has permitted their classification into two broad categories. Late competence genes are expressed under competence control and specify products required for the binding, uptake, and processing of transforming DNA. Regulatory genes specify products that are needed for the expression of the late genes. Several of the late competence gene products have been shown to be membrane localized, and others are predicted to be membrane associated on the basis of amino acid sequence data. Several of these predicted protein sequences show a striking resemblance to gene products that are involved in the export and/or assembly of extracellular proteins and structures in gram-negative organisms. This observation is consistent with the idea that the late products are directly involved in transport of DNA and is equally consistent with the notion that they play a morphogenetic role in the assembly of a transport apparatus. The competence regulatory apparatus constitutes an elaborate signal transduction system that senses and interprets environmental information and passes this information to the competence-specific transcriptional machinery. Many of the regulatory gene products have been identified and partially characterized, and their interactions have been studied genetically and in some cases biochemically as well. These include several

  16. "Teaching as a Competency": competencies for medical educators.

    PubMed

    Srinivasan, Malathi; Li, Su-Ting T; Meyers, Fredrick J; Pratt, Daniel D; Collins, John B; Braddock, Clarence; Skeff, Kelley M; West, Daniel C; Henderson, Mark; Hales, Robert E; Hilty, Donald M

    2011-10-01

    Most medical faculty receive little or no training about how to be effective teachers, even when they assume major educational leadership roles. To identify the competencies required of an effective teacher in medical education, the authors developed a comprehensive conceptual model. After conducting a literature search, the authors met at a two-day conference (2006) with 16 medical and nonmedical educators from 10 different U.S. and Canadian organizations and developed an initial draft of the "Teaching as a Competency" conceptual model. Conference participants used the physician competencies (from the Accreditation Council for Graduate Medical Education [ACGME]) and the roles (from the Royal College's Canadian Medical Education Directives for Specialists [CanMEDS]) to define critical skills for medical educators. The authors then refined this initial framework through national/regional conference presentations (2007, 2008), an additional literature review, and expert input. Four core values grounded this framework: learner engagement, learner-centeredness, adaptability, and self-reflection. The authors identified six core competencies, based on the ACGME competencies framework: medical (or content) knowledge; learner- centeredness; interpersonal and communication skills; professionalism and role modeling; practice-based reflection; and systems-based practice. They also included four specialized competencies for educators with additional programmatic roles: program design/implementation, evaluation/scholarship, leadership, and mentorship. The authors then cross-referenced the competencies with educator roles, drawing from CanMEDS, to recognize role-specific skills. The authors have explored their framework's strengths, limitations, and applications, which include targeted faculty development, evaluation, and resource allocation. The Teaching as a Competency framework promotes a culture of effective teaching and learning.

  17. "Teaching as a Competency": competencies for medical educators.

    PubMed

    Srinivasan, Malathi; Li, Su-Ting T; Meyers, Fredrick J; Pratt, Daniel D; Collins, John B; Braddock, Clarence; Skeff, Kelley M; West, Daniel C; Henderson, Mark; Hales, Robert E; Hilty, Donald M

    2011-10-01

    Most medical faculty receive little or no training about how to be effective teachers, even when they assume major educational leadership roles. To identify the competencies required of an effective teacher in medical education, the authors developed a comprehensive conceptual model. After conducting a literature search, the authors met at a two-day conference (2006) with 16 medical and nonmedical educators from 10 different U.S. and Canadian organizations and developed an initial draft of the "Teaching as a Competency" conceptual model. Conference participants used the physician competencies (from the Accreditation Council for Graduate Medical Education [ACGME]) and the roles (from the Royal College's Canadian Medical Education Directives for Specialists [CanMEDS]) to define critical skills for medical educators. The authors then refined this initial framework through national/regional conference presentations (2007, 2008), an additional literature review, and expert input. Four core values grounded this framework: learner engagement, learner-centeredness, adaptability, and self-reflection. The authors identified six core competencies, based on the ACGME competencies framework: medical (or content) knowledge; learner- centeredness; interpersonal and communication skills; professionalism and role modeling; practice-based reflection; and systems-based practice. They also included four specialized competencies for educators with additional programmatic roles: program design/implementation, evaluation/scholarship, leadership, and mentorship. The authors then cross-referenced the competencies with educator roles, drawing from CanMEDS, to recognize role-specific skills. The authors have explored their framework's strengths, limitations, and applications, which include targeted faculty development, evaluation, and resource allocation. The Teaching as a Competency framework promotes a culture of effective teaching and learning. PMID:21869655

  18. Socialization of perceived academic competence among highly competent children.

    PubMed

    Phillips, D A

    1987-10-01

    A sample of 81 academically competent third graders and their parents were studied (1) to determine whether the illusion of incompetence documented for fifth graders appears in younger children, (2) to examine whether parents' competence-related perceptions significantly distinguish children with varying levels of perceived academic competence, and (3) to develop a predictive model of the association between parent and child competence beliefs. More than 20% of the children--equal proportions of girls and boys--had self-perceptions that seriously underestimated their actual high abilities, and displayed a corresponding pattern of disparaging self- and other-achievement attitudes. Mothers' and fathers' perceptions of their children's abilities varied significantly with the perceived competence status of the children, as did the children's perceptions of their parents' appraisals. Using path analysis, preliminary support was found for a model in which children's perceptions of competence are influenced more by their parents' appraisals than by objective evidence of their achievements. The results are discussed in the context of research on the socialization of math attitudes and new work on parental belief systems. PMID:3665647

  19. Design criteria for ultrafast optical parametric amplifiers

    NASA Astrophysics Data System (ADS)

    Manzoni, C.; Cerullo, G.

    2016-10-01

    Optical parametric amplifiers (OPAs) exploit second-order nonlinearity to transfer energy from a fixed frequency pump pulse to a variable frequency signal pulse, and represent an easy way of tuning over a broad range the frequency of an otherwise fixed femtosecond laser system. OPAs can also act as broadband amplifiers, transferring energy from a narrowband pump to a broadband signal and thus considerably shortening the duration of the pump pulse. Due to these unique properties, OPAs are nowadays ubiquitous in ultrafast laser laboratories, and are employed by many users, such as solid state physicists, atomic/molecular physicists, chemists and biologists, who are not experts in ultrafast optics. This tutorial paper aims at providing the non-specialist reader with a self-consistent guide to the physical foundations of OPAs, deriving the main equations describing their performance and discussing how they can be used to understand their most important working parameters (frequency tunability, bandwidth, pulse energy/repetition rate scalability, control over the carrier-envelope phase of the generated pulses). Based on this analysis, we derive practical design criteria for OPAs, showing how their performance depends on the type of the nonlinear interaction (crystal type, phase-matching configuration, crystal length), on the characteristics of the pump pulse (frequency, duration, energy, repetition rate) and on the OPA architecture.

  20. Parametric Cost Analysis: A Design Function

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.

    1989-01-01

    Parametric cost analysis uses equations to map measurable system attributes into cost. The measures of the system attributes are called metrics. The equations are called cost estimating relationships (CER's), and are obtained by the analysis of cost and technical metric data of products analogous to those to be estimated. Examples of system metrics include mass, power, failure_rate, mean_time_to_repair, energy _consumed, payload_to_orbit, pointing_accuracy, manufacturing_complexity, number_of_fasteners, and percent_of_electronics_weight. The basic assumption is that a measurable relationship exists between system attributes and the cost of the system. If a function exists, the attributes are cost drivers. Candidates for metrics include system requirement metrics and engineering process metrics. Requirements are constraints on the engineering process. From optimization theory we know that any active constraint generates cost by not permitting full optimization of the objective. Thus, requirements are cost drivers. Engineering processes reflect a projection of the requirements onto the corporate culture, engineering technology, and system technology. Engineering processes are an indirect measure of the requirements and, hence, are cost drivers.

  1. Parametric optimization of inverse trapezoid oleophobic surfaces.

    PubMed

    Cavalli, Andrea; Bøggild, Peter; Okkels, Fridolin

    2012-12-18

    In this paper, we introduce a comprehensive and versatile approach to the parametric shape optimization of oleophobic surfaces. We evaluate the performance of inverse trapezoid microstructures in terms of three objective parameters: apparent contact angle, maximum sustainable hydrostatic pressure, and mechanical robustness (Im, M.; Im, H:; Lee, J.H.; Yoon, J.B.; Choi, Y.K. A robust superhydrophobic and superoleophobic surface with inverse-trapezoidal microstructures on a large transparent flexible substrate. Soft Matter 2010, 6, 1401-1404; Im, M.; Im, H:; Lee, J.H.; Yoon, J.B.; Choi, Y.K. Analytical Modeling and Thermodynamic Analysis of Robust Superhydrophobic Surfaces with Inverse-Trapezoidal Microstructures. Langmuir 2010, 26, 17389-17397). We find that each of these parameters, if considered alone, would give trivial optima, while their interplay provides a well-defined optimal shape and aspect ratio. The inclusion of mechanical robustness in combination with conventional performance characteristics favors solutions relevant for practical applications, as mechanical stability is a critical issue not often addressed in idealized models. PMID:23078017

  2. Parametric Decay during HHFW on NSTX

    SciTech Connect

    J.R. Wilson; S. Bernabei; T. Biewer; S. Diem; J. Hosea; B. LeBlanc; C.K. Phillips; P. Ryan; D.W. Swain

    2005-05-13

    High Harmonic Fast Wave (HHFW) heating experiments on NSTX have been observed to be accompanied by significant edge ion heating (T{sub i} >> T{sub e}). This heating is found to be anisotropic with T{sub perp} > T{sub par}. Simultaneously, coherent oscillations have been detected with an edge Langmuir probe. The oscillations are consistent with parametric decay of the incident fast wave ({omega} > 13{omega}{sub ci}) into ion Bernstein waves and an unobserved ion-cyclotron quasi-mode. The observation of anisotropic heating is consistent with Bernstein wave damping, and the Bernstein waves should completely damp in the plasma periphery as they propagate toward a cyclotron harmonic resonance. The number of daughter waves is found to increase with rf power, and to increase as the incident wave's toroidal wavelength increases. The frequencies of the daughter wave are separated by the edge ion cyclotron frequency. Theoretical calculations of the threshold for this decay in uniform plasma indicate an extremely small value of incident power should be required to drive the instability. While such decays are commonly observed at lower harmonics in conventional ICRF heating scenarios, they usually do not involve the loss of significant wave power from the pump wave. On NSTX an estimate of the power loss can be found by calculating the minimum power required to support the edge ion heating (presumed to come from the decay Bernstein wave). This calculation indicates at least 20-30% of the incident rf power ends up as decay waves.

  3. Parametric Study of Variable Emissivity Radiator Surfaces

    NASA Technical Reports Server (NTRS)

    Grob, Lisa M.; Swanson, Theodore D.

    2000-01-01

    The goal of spacecraft thermal design is to accommodate a high function satellite in a low weight and real estate package. The extreme environments that the satellite is exposed during its orbit are handled using passive and active control techniques. Heritage passive heat rejection designs are sized for the hot conditions and augmented for the cold end with heaters. The active heat rejection designs to date are heavy, expensive and/or complex. Incorporating an active radiator into the design that is lighter, cheaper and more simplistic will allow designers to meet the previously stated goal of thermal spacecraft design Varying the radiator's surface properties without changing the radiating area (as with VCHP), or changing the radiators' views (traditional louvers) is the objective of the variable emissivity (vary-e) radiator technologies. A parametric evaluation of the thermal performance of three such technologies is documented in this paper. Comparisons of the Micro-Electromechanical Systems (MEMS), Electrochromics, and Electrophoretics radiators to conventional radiators, both passive and active are quantified herein. With some noted limitations, the vary-e radiator surfaces provide significant advantages over traditional radiators and a promising alternative design technique for future spacecraft thermal systems.

  4. A Parametric Study of Spur Gear Dynamics

    NASA Technical Reports Server (NTRS)

    Lin, Hsiang Hsi; Liou, Chuen-Huei

    1998-01-01

    A parametric study of a spur gear system was performed through a numerical analysis approach. This study used the gear dynamic program DANST, a computer simulator, to determine the dynamic behavior of a spur gear system. The analytical results have taken the deflection of shafts and bearings into consideration for static analysis, and the influence of these deflections on gear dynamics was investigated. Damping in the gear system usually is an unknown quantity, but it has an important effect in resonance vibration. Typical values as reported in the literature were used in the present analysis. The dynamic response due to different damping factors was evaluated and compared. The effect of the contact ratio on spur gear dynamic load and dynamic stress was investigated through a parameter study. The contact ratio was varied over the range of 1.26 to 2.46 by adjusting the tooth addendum. Gears with contact ratio near 2.0 were found to have the most favorable dynamic performance.

  5. Parametric testing of coal electrostatic precipitator performance

    SciTech Connect

    Canadas, L.; Navarrete, B.; Ollero, P.; Salvador, L.

    1997-12-31

    The effect of internal geometry, electrode type, and operating conditions on the performance of a coal electrostatic precipitator (ESP) has been analyzed by means of an extensive parametric testing program. Tests under different conditions of plate spacing, discharge electrodes, gas velocity, and energization wave form have been performed using two extreme coal types, with very high and low resistivity ashes, respectively. The study was made by means of a pilot installation operating with a flue gas slipstream drawn upstream of a power plant ESP. The experimental plant includes a specifically designed pilot ESP, able to admit an internal modification of plate spacing and electrode type. The ESP is equipped with a microprocessor controlled power supply which can generate both continuous and intermittent rectified current. The measured sensitivity of the precipitation process to the dust properties, filter configuration, electrode type, and energization method is presented, covering both the ESP efficiency evolution and the associated power consumption. The results of this work allow to extract practical conclusions about specification of ESP design and size for a given application, and assess the conditions in which use of wide plate spacing, new electrode geometries, or intermittent current are actually advantageous. 11 refs., 6 figs., 5 tabs.

  6. Parametric Testing of Launch Vehicle FDDR Models

    NASA Technical Reports Server (NTRS)

    Schumann, Johann; Bajwa, Anupa; Berg, Peter; Thirumalainambi, Rajkumar

    2011-01-01

    For the safe operation of a complex system like a (manned) launch vehicle, real-time information about the state of the system and potential faults is extremely important. The on-board FDDR (Failure Detection, Diagnostics, and Response) system is a software system to detect and identify failures, provide real-time diagnostics, and to initiate fault recovery and mitigation. The ERIS (Evaluation of Rocket Integrated Subsystems) failure simulation is a unified Matlab/Simulink model of the Ares I Launch Vehicle with modular, hierarchical subsystems and components. With this model, the nominal flight performance characteristics can be studied. Additionally, failures can be injected to see their effects on vehicle state and on vehicle behavior. A comprehensive test and analysis of such a complicated model is virtually impossible. In this paper, we will describe, how parametric testing (PT) can be used to support testing and analysis of the ERIS failure simulation. PT uses a combination of Monte Carlo techniques with n-factor combinatorial exploration to generate a small, yet comprehensive set of parameters for the test runs. For the analysis of the high-dimensional simulation data, we are using multivariate clustering to automatically find structure in this high-dimensional data space. Our tools can generate detailed HTML reports that facilitate the analysis.

  7. Parametric analysis of a magnetized cylindrical plasma

    SciTech Connect

    Ahedo, Eduardo

    2009-11-15

    The relevant macroscopic model, the spatial structure, and the parametric regimes of a low-pressure plasma confined by a cylinder and an axial magnetic field is discussed for the small-Debye length limit, making use of asymptotic techniques. The plasma response is fully characterized by three-dimensionless parameters, related to the electron gyroradius, and the electron and ion collision mean-free-paths. There are the unmagnetized regime, the main magnetized regime, and, for a low electron-collisionality plasma, an intermediate-magnetization regime. In the magnetized regimes, electron azimuthal inertia is shown to be a dominant phenomenon in part of the quasineutral plasma region and to set up before ion radial inertia. In the main magnetized regime, the plasma structure consists of a bulk diffusive region, a thin layer governed by electron inertia, a thinner sublayer controlled by ion inertia, and the non-neutral Debye sheath. The solution of the main inertial layer yields that the electron azimuthal energy near the wall is larger than the electron thermal energy, making electron resistivity effects non-negligible. The electron Boltzmann relation is satisfied only in the very vicinity of the Debye sheath edge. Ion collisionality effects are irrelevant in the magnetized regime. Simple scaling laws for plasma production and particle and energy fluxes to the wall are derived.

  8. Optical parametric oscillators for medical applications

    NASA Astrophysics Data System (ADS)

    Gloster, Lawrie A. W.; Golding, Paul S.; King, Terence A.

    1996-04-01

    In recent years optical parametric oscillators (OPOs) have undergone a renaissance largely due to the discovery of new nonlinear materials capable of wide continuous tuning ranges spanning from the UV to the near-infrared spectral regions. To date, however, OPOs have not been exploited in the medical field despite their advantages over the dye laser in terms of tuning range and solid state structure. We consider the development of an OPO based on barium borate (BBO) which can be tailored to suit applications in medicine. Converting the maximum number of pump photons to tunable signal and idler photons is of great importance to secure high-fluence radiation necessary for many treatments. With this in mind, we report on an all- solid-state system using BBO which has been optimized by computer modeling with the potential of delivering amplification factors of typically up to 20 over a continuous tuning range of 700 nm to 1000 nm. As an example of its biomedical application, we describe the selective excitation of biomolecules and chromophores for cell destruction using malachite green isothiocyanate labelled bacteria. The potential for development is reviewed towards other medical applications such as diagnostic sensing and phototherapy.

  9. Program Predicts Performance of Optical Parametric Oscillators

    NASA Technical Reports Server (NTRS)

    Cross, Patricia L.; Bowers, Mark

    2006-01-01

    A computer program predicts the performances of solid-state lasers that operate at wavelengths from ultraviolet through mid-infrared and that comprise various combinations of stable and unstable resonators, optical parametric oscillators (OPOs), and sum-frequency generators (SFGs), including second-harmonic generators (SHGs). The input to the program describes the signal, idler, and pump beams; the SFG and OPO crystals; and the laser geometry. The program calculates the electric fields of the idler, pump, and output beams at three locations (inside the laser resonator, just outside the input mirror, and just outside the output mirror) as functions of time for the duration of the pump beam. For each beam, the electric field is used to calculate the fluence at the output mirror, plus summary parameters that include the centroid location, the radius of curvature of the wavefront leaving through the output mirror, the location and size of the beam waist, and a quantity known, variously, as a propagation constant or beam-quality factor. The program provides a typical Windows interface for entering data and selecting files. The program can include as many as six plot windows, each containing four graphs.

  10. Optical parametric osicllators with improved beam quality

    DOEpatents

    Smith, Arlee V.; Alford, William J.

    2003-11-11

    An optical parametric oscillator (OPO) having an optical pump, which generates a pump beam at a pump frequency greater than a desired signal frequency, a nonlinear optical medium oriented so that a signal wave at the desired signal frequency and a corresponding idler wave are produced when the pump beam (wave) propagates through the nonlinear optical medium, resulting in beam walk off of the signal and idler waves, and an optical cavity which directs the signal wave to repeatedly pass through the nonlinear optical medium, said optical cavity comprising an equivalently even number of non-planar mirrors that produce image rotation on each pass through the nonlinear optical medium. Utilizing beam walk off where the signal wave and said idler wave have nonparallel Poynting vectors in the nonlinear medium and image rotation, a correlation zone of distance equal to approximately .rho.L.sub.crystal is created which, through multiple passes through the nonlinear medium, improves the beam quality of the OPO output.

  11. Non-parametric estimation of morphological lopsidedness

    NASA Astrophysics Data System (ADS)

    Giese, Nadine; van der Hulst, Thijs; Serra, Paolo; Oosterloo, Tom

    2016-09-01

    Asymmetries in the neutral hydrogen gas distribution and kinematics of galaxies are thought to be indicators for both gas accretion and gas removal processes. These are of fundamental importance for galaxy formation and evolution. Upcoming large blind H I surveys will provide tens of thousands of galaxies for a study of these asymmetries in a proper statistical way. Due to the large number of expected sources and the limited resolution of the majority of objects, detailed modelling is not feasible for most detections. We need fast, automatic and sensitive methods to classify these objects in an objective way. Existing non-parametric methods suffer from effects like the dependence on signal to noise, resolution and inclination. Here we show how to correctly take these effects into account and show ways to estimate the precision of the methods. We will use existing and modelled data to give an outlook on the performance expected for galaxies observed in the various sky surveys planned for e.g. WSRT/APERTIF and ASKAP.

  12. Parametric instabilities in picosecond time scales

    SciTech Connect

    Baldis, H.A.; Rozmus, W.; Labaune, C.; Mounaix, Ph.; Pesme, D.; Baton, S.; Tikhonchuk, V.T.

    1993-03-01

    The coupling of intense laser light with plasmas is a rich field of plasma physics, with many applications. Among these are inertial confinement fusion (ICF), x-ray lasers, particle acceleration, and x-ray sources. Parametric instabilities have been studied for many years because of their importance to ICF; with laser pulses with duration of approximately a nanosecond, and laser intensities in the range 10{sup 14}--10{sup 15}W/cm{sup 2} these instabilities are of crucial concern because of a number of detrimental effects. Although the laser pulse duration of interest for these studies are relatively long, it has been evident in the past years that to reach an understanding of these instabilities requires their characterization and analysis in picosecond time scales. At the laser intensities of interest, the growth rate for stimulated Brillouin scattering (SBS) is of the order of picoseconds, and of an order of magnitude shorter for stimulated Raman scattering (SRS). In this paper the authors discuss SBS and SRS in the context of their evolution in picosecond time scales. They describe the fundamental concepts associated with their growth and saturation, and recent work on the nonlinear treatment required for the modeling of these instabilities at high laser intensities.

  13. Parametric optimization of inverse trapezoid oleophobic surfaces.

    PubMed

    Cavalli, Andrea; Bøggild, Peter; Okkels, Fridolin

    2012-12-18

    In this paper, we introduce a comprehensive and versatile approach to the parametric shape optimization of oleophobic surfaces. We evaluate the performance of inverse trapezoid microstructures in terms of three objective parameters: apparent contact angle, maximum sustainable hydrostatic pressure, and mechanical robustness (Im, M.; Im, H:; Lee, J.H.; Yoon, J.B.; Choi, Y.K. A robust superhydrophobic and superoleophobic surface with inverse-trapezoidal microstructures on a large transparent flexible substrate. Soft Matter 2010, 6, 1401-1404; Im, M.; Im, H:; Lee, J.H.; Yoon, J.B.; Choi, Y.K. Analytical Modeling and Thermodynamic Analysis of Robust Superhydrophobic Surfaces with Inverse-Trapezoidal Microstructures. Langmuir 2010, 26, 17389-17397). We find that each of these parameters, if considered alone, would give trivial optima, while their interplay provides a well-defined optimal shape and aspect ratio. The inclusion of mechanical robustness in combination with conventional performance characteristics favors solutions relevant for practical applications, as mechanical stability is a critical issue not often addressed in idealized models.

  14. Parametric probability distributions for anomalous change detection

    SciTech Connect

    Theiler, James P; Foy, Bernard R; Wohlberg, Brendt E; Scovel, James C

    2010-01-01

    The problem of anomalous change detection arises when two (or possibly more) images are taken of the same scene, but at different times. The aim is to discount the 'pervasive differences' that occur thoughout the imagery, due to the inevitably different conditions under which the images were taken (caused, for instance, by differences in illumination, atmospheric conditions, sensor calibration, or misregistration), and to focus instead on the 'anomalous changes' that actually take place in the scene. In general, anomalous change detection algorithms attempt to model these normal or pervasive differences, based on data taken directly from the imagery, and then identify as anomalous those pixels for which the model does not hold. For many algorithms, these models are expressed in terms of probability distributions, and there is a class of such algorithms that assume the distributions are Gaussian. By considering a broader class of distributions, however, a new class of anomalous change detection algorithms can be developed. We consider several parametric families of such distributions, derive the associated change detection algorithms, and compare the performance with standard algorithms that are based on Gaussian distributions. We find that it is often possible to significantly outperform these standard algorithms, even using relatively simple non-Gaussian models.

  15. Parametric and Non-Parametric Vibration-Based Structural Identification Under Earthquake Excitation

    NASA Astrophysics Data System (ADS)

    Pentaris, Fragkiskos P.; Fouskitakis, George N.

    2014-05-01

    The problem of modal identification in civil structures is of crucial importance, and thus has been receiving increasing attention in recent years. Vibration-based methods are quite promising as they are capable of identifying the structure's global characteristics, they are relatively easy to implement and they tend to be time effective and less expensive than most alternatives [1]. This paper focuses on the off-line structural/modal identification of civil (concrete) structures subjected to low-level earthquake excitations, under which, they remain within their linear operating regime. Earthquakes and their details are recorded and provided by the seismological network of Crete [2], which 'monitors' the broad region of south Hellenic arc, an active seismic region which functions as a natural laboratory for earthquake engineering of this kind. A sufficient number of seismic events are analyzed in order to reveal the modal characteristics of the structures under study, that consist of the two concrete buildings of the School of Applied Sciences, Technological Education Institute of Crete, located in Chania, Crete, Hellas. Both buildings are equipped with high-sensitivity and accuracy seismographs - providing acceleration measurements - established at the basement (structure's foundation) presently considered as the ground's acceleration (excitation) and at all levels (ground floor, 1st floor, 2nd floor and terrace). Further details regarding the instrumentation setup and data acquisition may be found in [3]. The present study invokes stochastic, both non-parametric (frequency-based) and parametric methods for structural/modal identification (natural frequencies and/or damping ratios). Non-parametric methods include Welch-based spectrum and Frequency response Function (FrF) estimation, while parametric methods, include AutoRegressive (AR), AutoRegressive with eXogeneous input (ARX) and Autoregressive Moving-Average with eXogeneous input (ARMAX) models[4, 5

  16. Experimental Sentinel-2 LAI estimation using parametric, non-parametric and physical retrieval methods - A comparison

    NASA Astrophysics Data System (ADS)

    Verrelst, Jochem; Rivera, Juan Pablo; Veroustraete, Frank; Muñoz-Marí, Jordi; Clevers, Jan G. P. W.; Camps-Valls, Gustau; Moreno, José

    2015-10-01

    Given the forthcoming availability of Sentinel-2 (S2) images, this paper provides a systematic comparison of retrieval accuracy and processing speed of a multitude of parametric, non-parametric and physically-based retrieval methods using simulated S2 data. An experimental field dataset (SPARC), collected at the agricultural site of Barrax (Spain), was used to evaluate different retrieval methods on their ability to estimate leaf area index (LAI). With regard to parametric methods, all possible band combinations for several two-band and three-band index formulations and a linear regression fitting function have been evaluated. From a set of over ten thousand indices evaluated, the best performing one was an optimized three-band combination according to (ρ560 -ρ1610 -ρ2190) / (ρ560 +ρ1610 +ρ2190) with a 10-fold cross-validation RCV2 of 0.82 (RMSECV : 0.62). This family of methods excel for their fast processing speed, e.g., 0.05 s to calibrate and validate the regression function, and 3.8 s to map a simulated S2 image. With regard to non-parametric methods, 11 machine learning regression algorithms (MLRAs) have been evaluated. This methodological family has the advantage of making use of the full optical spectrum as well as flexible, nonlinear fitting. Particularly kernel-based MLRAs lead to excellent results, with variational heteroscedastic (VH) Gaussian Processes regression (GPR) as the best performing method, with a RCV2 of 0.90 (RMSECV : 0.44). Additionally, the model is trained and validated relatively fast (1.70 s) and the processed image (taking 73.88 s) includes associated uncertainty estimates. More challenging is the inversion of a PROSAIL based radiative transfer model (RTM). After the generation of a look-up table (LUT), a multitude of cost functions and regularization options were evaluated. The best performing cost function is Pearson's χ -square. It led to a R2 of 0.74 (RMSE: 0.80) against the validation dataset. While its validation went fast

  17. Thermal lensing in silver gallium selenide parametric oscillator crystals.

    PubMed

    Marquardt, C L; Cooper, D G; Budni, P A; Knights, M G; Schepler, K L; Dedomenico, R; Catella, G C

    1994-05-20

    We performed an experimental investigation of thermal lensing in silver gallium selenide (AgGaSe(2)) optical parametric oscillator crystals pumped by a 2-µm laser at ambient temperature. We determined an empirical expression for the effective thermal focusing power in terms of the pump power, beam diameter, crystal length, and absorption coefficient. This relation may be used to estimate average power limitations in designing AgGaSe(2) optical parametric oscillators. We also demonstrated an 18% slope efficiency from a 2-µm pumped AgGaSe(2) optical parametric oscillator operated at 77 K, at which temperature thermal lensing is substantially reduced because of an increase in the thermal conductivity and a decrease in the thermal index gradient dn/dT. Cryogenic cooling may provide an additional option for scaling up the average power capability of a 2-µm pumped AgGaSe(2) optical parametric oscillator.

  18. Studies of nondegenerate, quasi-phase-matched optical parametric amplification

    SciTech Connect

    Lawrence Livermore National Laboratory

    2004-03-18

    We have performed extensive numerical studies of quasi-phase-matched optical parametric amplification with the aim to improve its nondegenerate spectral bandwidth. Our multi-section fan-out design calculations indicate a 35-fold increase in spectral bandwidth.

  19. Competency-Based Achievement System

    PubMed Central

    Ross, Shelley; Poth, Cheryl N.; Donoff, Michel; Humphries, Paul; Steiner, Ivan; Schipper, Shirley; Janke, Fred; Nichols, Darren

    2011-01-01

    Abstract Problem addressed Family medicine residency programs require innovative means to assess residents’ competence in “soft” skills (eg, patient-centred care, communication, and professionalism) and to identify residents who are having difficulty early enough in their residency to provide remedial training. Objective of program To develop a method to assess residents’ competence in various skills and to identify residents who are having difficulty. Program description The Competency-Based Achievement System (CBAS) was designed to measure competence using 3 main principles: formative feedback, guided self-assessment, and regular face-to-face meetings. The CBAS is resident driven and provides a framework for meaningful interactions between residents and advisors. Residents use the CBAS to organize and review their feedback, to guide their own assessment of their progress, and to discern their future learning needs. Advisors use the CBAS to monitor, guide, and verify residents’ knowledge of and competence in important skills. Conclusion By focusing on specific skills and behaviour, the CBAS enables residents and advisors to make formative assessments and to communicate their findings. Feedback indicates that the CBAS is a user-friendly and helpful system to assess competence. PMID:21918129

  20. Parametric Study of Reactive Melt Infiltration

    NASA Technical Reports Server (NTRS)

    Nelson, Emily S.; Colella, Phillip

    2000-01-01

    Reactive melt infiltration is viewed as a promising means of achieving near-net shape manufacturing with quick processing time and at low cost. Since the reactants and products are, in general, of varying density, overall conservation of mass dictates that there is a force related to chemical conversion which can directly influence infiltration behavior. In effect, the driving pressure forces may compete with the forces from chemical conversion, affecting the advancement of the front. We have developed a two-dimensional numerical code to examine these effects, using reaction-formed silicon carbide as a model system for this process. We have examined a range of initial porosities, pore radii, and reaction rates in order to investigate their effects on infiltration dynamics.