WorldWideScience

Sample records for models additionally adjusting

  1. On adjustment for auxiliary covariates in additive hazard models for the analysis of randomized experiments

    DEFF Research Database (Denmark)

    Vansteelandt, S.; Martinussen, Torben; Tchetgen, E. J Tchetgen

    2014-01-01

    We consider additive hazard models (Aalen, 1989) for the effect of a randomized treatment on a survival outcome, adjusting for auxiliary baseline covariates. We demonstrate that the Aalen least-squares estimator of the treatment effect parameter is asymptotically unbiased, even when the hazard...... that, in view of its robustness against model misspecification, Aalen least-squares estimation is attractive for evaluating treatment effects on a survival outcome in randomized experiments, and the primary reasons to consider baseline covariate adjustment in such settings could be interest in subgroup......'s dependence on time or on the auxiliary covariates is misspecified, and even away from the null hypothesis of no treatment effect. We furthermore show that adjustment for auxiliary baseline covariates does not change the asymptotic variance of the estimator of the effect of a randomized treatment. We conclude...

  2. Analysis of error-prone survival data under additive hazards models: measurement error effects and adjustments.

    Science.gov (United States)

    Yan, Ying; Yi, Grace Y

    2016-07-01

    Covariate measurement error occurs commonly in survival analysis. Under the proportional hazards model, measurement error effects have been well studied, and various inference methods have been developed to correct for error effects under such a model. In contrast, error-contaminated survival data under the additive hazards model have received relatively less attention. In this paper, we investigate this problem by exploring measurement error effects on parameter estimation and the change of the hazard function. New insights of measurement error effects are revealed, as opposed to well-documented results for the Cox proportional hazards model. We propose a class of bias correction estimators that embraces certain existing estimators as special cases. In addition, we exploit the regression calibration method to reduce measurement error effects. Theoretical results for the developed methods are established, and numerical assessments are conducted to illustrate the finite sample performance of our methods.

  3. Risk-adjusted econometric model to estimate postoperative costs: an additional instrument for monitoring performance after major lung resection.

    Science.gov (United States)

    Brunelli, Alessandro; Salati, Michele; Refai, Majed; Xiumé, Francesco; Rocco, Gaetano; Sabbatini, Armando

    2007-09-01

    The objectives of this study were to develop a risk-adjusted model to estimate individual postoperative costs after major lung resection and to use it for internal economic audit. Variable and fixed hospital costs were collected for 679 consecutive patients who underwent major lung resection from January 2000 through October 2006 at our unit. Several preoperative variables were used to develop a risk-adjusted econometric model from all patients operated on during the period 2000 through 2003 by a stepwise multiple regression analysis (validated by bootstrap). The model was then used to estimate the postoperative costs in the patients operated on during the 3 subsequent periods (years 2004, 2005, and 2006). Observed and predicted costs were then compared within each period by the Wilcoxon signed rank test. Multiple regression and bootstrap analysis yielded the following model predicting postoperative cost: 11,078 + 1340.3X (age > 70 years) + 1927.8X cardiac comorbidity - 95X ppoFEV1%. No differences between predicted and observed costs were noted in the first 2 periods analyzed (year 2004, $6188.40 vs $6241.40, P = .3; year 2005, $6308.60 vs $6483.60, P = .4), whereas in the most recent period (2006) observed costs were significantly lower than the predicted ones ($3457.30 vs $6162.70, P < .0001). Greater precision in predicting outcome and costs after therapy may assist clinicians in the optimization of clinical pathways and allocation of resources. Our economic model may be used as a methodologic template for economic audit in our specialty and complement more traditional outcome measures in the assessment of performance.

  4. Convexity Adjustments for ATS Models

    DEFF Research Database (Denmark)

    Murgoci, Agatha; Gaspar, Raquel M.

    . As a result we classify convexity adjustments into forward adjustments and swaps adjustments. We, then, focus on affine term structure (ATS) models and, in this context, conjecture convexity adjustments should be related of affine functionals. In the case of forward adjustments, we show how to obtain exact...... formulas. Concretely for LIBOR in arrears (LIA) contracts, we derive the system of Riccatti ODE-s one needs to compute to obtain the exact adjustment. Based upon the ideas of Schrager and Pelsser (2006) we are also able to derive general swap adjustments useful, in particular, when dealing with constant...

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

    Science.gov (United States)

    Donoghoe, Mark W; Marschner, Ian C

    2016-08-15

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

  6. Adjustment or updating of models

    Indian Academy of Sciences (India)

    Department of Mechanical Engineering, Imperial College of Science, .... It is first necessary to decide upon the level of accuracy, or correctness which is sought from the adjustment of the initial model, and this will be heavily influenced by the eventual application of the ..... reviewing the degree of success attained.

  7. Fused Lasso Additive Model.

    Science.gov (United States)

    Petersen, Ashley; Witten, Daniela; Simon, Noah

    2016-01-01

    We consider the problem of predicting an outcome variable using p covariates that are measured on n independent observations, in a setting in which additive, flexible, and interpretable fits are desired. We propose the fused lasso additive model (FLAM), in which each additive function is estimated to be piecewise constant with a small number of adaptively-chosen knots. FLAM is the solution to a convex optimization problem, for which a simple algorithm with guaranteed convergence to a global optimum is provided. FLAM is shown to be consistent in high dimensions, and an unbiased estimator of its degrees of freedom is proposed. We evaluate the performance of FLAM in a simulation study and on two data sets. Supplemental materials are available online, and the R package flam is available on CRAN.

  8. Model Additional Protocol

    International Nuclear Information System (INIS)

    Rockwood, Laura

    2001-01-01

    Since the end of the cold war a series of events has changed the circumstances and requirements of the safeguards system. The discovery of a clandestine nuclear weapons program in Iraq, the continuing difficulty in verifying the initial report of Democratic People's Republic of Korea upon entry into force of their safeguards agreement, and the decision of the South African Government to give up its nuclear weapons program and join the Treaty on the Non-Proliferation of Nuclear Weapons have all played a role in an ambitious effort by IAEA Member States and the Secretariat to strengthen the safeguards system. A major milestone in this effort was reached in May 1997 when the IAEA Board of Governors approved a Model Protocol Additional to Safeguards Agreements. The Model Additional Protocol was negotiated over a period of less than a year by an open-ended committee of the Board involving some 70 Member States and two regional inspectorates. The IAEA is now in the process of negotiating additional protocols, State by State, and implementing them. These additional protocols will provide the IAEA with rights of access to information about all activities related to the use of nuclear material in States with comprehensive safeguards agreements and greatly expanded physical access for IAEA inspectors to confirm or verify this information. In conjunction with this, the IAEA is working on the integration of these measures with those provided for in comprehensive safeguards agreements, with a view to maximizing the effectiveness and efficiency, within available resources, the implementation of safeguards. Details concerning the Model Additional Protocol are given. (author)

  9. Premium adjustment: actuarial analysis on epidemiological models ...

    African Journals Online (AJOL)

    Premium adjustment: actuarial analysis on epidemiological models. DEA Omorogbe, SO Edobor. Abstract. In this paper, we analyse insurance premium adjustment in the context of an epidemiological model where the insurer's future financial liability is greater than the premium from patients. In this situation, it becomes ...

  10. Adjustment or updating of models

    Indian Academy of Sciences (India)

    While the model is defined in terms of these spatial parameters, .... (mode shapes defined at the n DOFs of a typical modal test in place of the complete N DOFs .... In these expressions,. N И the number of degrees of freedom in the model, while N1 and N2 are the numbers of mass and stiffness elements to be corrected ...

  11. Extendable linearised adjustment model for deformation analysis

    NARCIS (Netherlands)

    Hiddo Velsink

    2015-01-01

    Author supplied: "This paper gives a linearised adjustment model for the affine, similarity and congruence transformations in 3D that is easily extendable with other parameters to describe deformations. The model considers all coordinates stochastic. Full positive semi-definite covariance matrices

  12. Extendable linearised adjustment model for deformation analysis

    NARCIS (Netherlands)

    Velsink, H.

    2015-01-01

    This paper gives a linearised adjustment model for the affine, similarity and congruence transformations in 3D that is easily extendable with other parameters to describe deformations. The model considers all coordinates stochastic. Full positive semi-definite covariance matrices and correlation

  13. The additive and interactive effects of parenting and temperament in predicting adjustment problems of children of divorce.

    Science.gov (United States)

    Lengua, L J; Wolchik, S A; Sandler, I N; West, S G

    2000-06-01

    Investigated the interaction between parenting and temperament in predicting adjustment problems in children of divorce. The study utilized a sample of 231 mothers and children, 9 to 12 years old, who had experienced divorce within the previous 2 years. Both mothers' and children's reports on parenting, temperament, and adjustment variables were obtained and combined to create cross-reporter measures of the variables. Parenting and temperament were directly and independently related to outcomes consistent with an additive model of their effects. Significant interactions indicated that parental rejection was more strongly related to adjustment problems for children low in positive emotionality, and inconsistent discipline was more strongly related to adjustment problems for children high in impulsivity. These findings suggest that children who are high in impulsivity may be at greater risk for developing problems, whereas positive emotionality may operate as a protective factor, decreasing the risk of adjustment problems in response to negative parenting.

  14. Business models for additive manufacturing

    DEFF Research Database (Denmark)

    Hadar, Ronen; Bilberg, Arne; Bogers, Marcel

    2015-01-01

    a manufacturer-centric to a consumer-centric value logic. A major shift includes a move from centralized to decentralized supply chains, where consumer goods manufacturers can implement a “hybrid” approach with a focus on localization and accessibility or develop a fully personalized model where the consumer...... of creating and capturing value. In this paper, we explore the implications that AM technologies have for manufacturing systems in the new business models that they enable. In particular, we consider how a consumer goods manufacturer can organize the operations of a more open business model when moving from...... effectively takes over the productive activities of the manufacturer. We discuss some of the main implications for research and practice of consumer-centric business models and the changing decoupling point in consumer goods’ manufacturing supply chains....

  15. Effect of Flux Adjustments on Temperature Variability in Climate Models

    International Nuclear Information System (INIS)

    Duffy, P.; Bell, J.; Covey, C.; Sloan, L.

    1999-01-01

    It has been suggested that ''flux adjustments'' in climate models suppress simulated temperature variability. If true, this might invalidate the conclusion that at least some of observed temperature increases since 1860 are anthropogenic, since this conclusion is based in part on estimates of natural temperature variability derived from flux-adjusted models. We assess variability of surface air temperatures in 17 simulations of internal temperature variability submitted to the Coupled Model Intercomparison Project. By comparing variability in flux-adjusted vs. non-flux adjusted simulations, we find no evidence that flux adjustments suppress temperature variability in climate models; other, largely unknown, factors are much more important in determining simulated temperature variability. Therefore the conclusion that at least some of observed temperature increases are anthropogenic cannot be questioned on the grounds that it is based in part on results of flux-adjusted models. Also, reducing or eliminating flux adjustments would probably do little to improve simulations of temperature variability

  16. Structured Dimensionality Reduction for Additive Model Regression

    OpenAIRE

    Fawzi, Alhussein; Fiot, Jean-Baptiste; Chen, Bei; Sinn, Mathieu; Frossard, Pascal

    2016-01-01

    Additive models are regression methods which model the response variable as the sum of univariate transfer functions of the input variables. Key benefits of additive models are their accuracy and interpretability on many real-world tasks. Additive models are however not adapted to problems involving a large number (e.g., hundreds) of input variables, as they are prone to overfitting in addition to losing interpretability. In this paper, we introduce a novel framework for applying additive ...

  17. Player Modeling for Intelligent Difficulty Adjustment

    Science.gov (United States)

    Missura, Olana; Gärtner, Thomas

    In this paper we aim at automatically adjusting the difficulty of computer games by clustering players into different types and supervised prediction of the type from short traces of gameplay. An important ingredient of video games is to challenge players by providing them with tasks of appropriate and increasing difficulty. How this difficulty should be chosen and increase over time strongly depends on the ability, experience, perception and learning curve of each individual player. It is a subjective parameter that is very difficult to set. Wrong choices can easily lead to players stopping to play the game as they get bored (if underburdened) or frustrated (if overburdened). An ideal game should be able to adjust its difficulty dynamically governed by the player’s performance. Modern video games utilise a game-testing process to investigate among other factors the perceived difficulty for a multitude of players. In this paper, we investigate how machine learning techniques can be used for automatic difficulty adjustment. Our experiments confirm the potential of machine learning in this application.

  18. Estimate of multiplicative and additive age adjustment factors for milk yield for the Mediterranean Italian Buffalo Breed

    Directory of Open Access Journals (Sweden)

    E. Parlato

    2010-02-01

    Full Text Available This study was carried out to estimate multiplicative and additive age adjustment factors for milk yield for the Mediterranean Italian Buffalo Breed for a mature age base (55 months, parity 2 with a mixed model procedure. Fixed effects of age-parity classes and random effects of contemporary group, genetic and permanent environmental effects of cows were included in the model. Two data sets were formed: Data Set I consisted of 83,810 lactation records and was used to develop the age factors. Data Set II consisted of 115,242 lactation records and was used for validation of the age factors estimated from Data Set I. Additive and multiplicative factors followed the same trend within the three parities (parity 1, parity 2, and parity ≥ 3. Averages of milk yield by age class for Data Set II pre-adjusted with multiplicative and additive factors from Data Set I were similar and tended to follow a straight line as expected. However, multiplicative factors might be preferred to additive factors because they would be affected less by an increase of the average milk yield due to selection or management. Age factors were smoothed to reduce differences among factors for similar age-parity classes. The smoothed age factors showed only slight differences among averages for similar age-parity classes, which suggests that the smoothed age factors may be more appropriate than the original factors.

  19. Methodological aspects of journaling a dynamic adjusting entry model

    Directory of Open Access Journals (Sweden)

    Vlasta Kašparovská

    2011-01-01

    Full Text Available This paper expands the discussion of the importance and function of adjusting entries for loan receivables. Discussion of the cyclical development of adjusting entries, their negative impact on the business cycle and potential solutions has intensified during the financial crisis. These discussions are still ongoing and continue to be relevant to members of the professional public, banking regulators and representatives of international accounting institutions. The objective of this paper is to evaluate a method of journaling dynamic adjusting entries under current accounting law. It also expresses the authors’ opinions on the potential for consistently implementing basic accounting principles in journaling adjusting entries for loan receivables under a dynamic model.

  20. An approach to adjustment of relativistic mean field model parameters

    Directory of Open Access Journals (Sweden)

    Bayram Tuncay

    2017-01-01

    Full Text Available The Relativistic Mean Field (RMF model with a small number of adjusted parameters is powerful tool for correct predictions of various ground-state nuclear properties of nuclei. Its success for describing nuclear properties of nuclei is directly related with adjustment of its parameters by using experimental data. In the present study, the Artificial Neural Network (ANN method which mimics brain functionality has been employed for improvement of the RMF model parameters. In particular, the understanding capability of the ANN method for relations between the RMF model parameters and their predictions for binding energies (BEs of 58Ni and 208Pb have been found in agreement with the literature values.

  1. Storm Water Management Model Climate Adjustment Tool (SWMM-CAT)

    Science.gov (United States)

    The US EPA’s newest tool, the Stormwater Management Model (SWMM) – Climate Adjustment Tool (CAT) is meant to help municipal stormwater utilities better address potential climate change impacts affecting their operations. SWMM, first released in 1971, models hydrology and hydrauli...

  2. R.M. Solow Adjusted Model of Economic Growth

    Directory of Open Access Journals (Sweden)

    Ion Gh. Rosca

    2007-05-01

    Full Text Available Besides the models of M. Keynes, R.F. Harrod, E. Domar, D. Romer, Ramsey-Cass-Koopmans etc., the R.M. Solow model is part of the category which characterizes the economic growth. The paper proposes the study of the R.M. Solow adjusted model of economic growth, while the adjustment consisting in the model adaptation to the Romanian economic characteristics. The article is the first one from a three paper series dedicated to the macroeconomic modelling theme, using the R.M. Solow model, such as: “Measurement of the economic growth and extensions of the R.M. Solow adjusted model” and “Evolution scenarios at the Romanian economy level using the R.M. Solow adjusted model”. The analysis part of the model is based on the study of the equilibrium to the continuous case with some interpretations of the discreet one, by using the state diagram. The optimization problem at the economic level is also used; it is built up of a specified number of representative consumers and firms in order to reveal the interaction between these elements.

  3. Nonparametric and semiparametric dynamic additive regression models

    DEFF Research Database (Denmark)

    Scheike, Thomas Harder; Martinussen, Torben

    Dynamic additive regression models provide a flexible class of models for analysis of longitudinal data. The approach suggested in this work is suited for measurements obtained at random time points and aims at estimating time-varying effects. Both fully nonparametric and semiparametric models can...... in special cases. We investigate the finite sample properties of the estimators and conclude that the asymptotic results are valid for even samll samples....

  4. Parenting Stress, Mental Health, Dyadic Adjustment: A Structural Equation Model

    Directory of Open Access Journals (Sweden)

    Luca Rollè

    2017-05-01

    Full Text Available Objective: In the 1st year of the post-partum period, parenting stress, mental health, and dyadic adjustment are important for the wellbeing of both parents and the child. However, there are few studies that analyze the relationship among these three dimensions. The aim of this study is to investigate the relationships between parenting stress, mental health (depressive and anxiety symptoms, and dyadic adjustment among first-time parents.Method: We studied 268 parents (134 couples of healthy babies. At 12 months post-partum, both parents filled out, in a counterbalanced order, the Parenting Stress Index-Short Form, the Edinburgh Post-natal Depression Scale, the State-Trait Anxiety Inventory, and the Dyadic Adjustment Scale. Structural equation modeling was used to analyze the potential mediating effects of mental health on the relationship between parenting stress and dyadic adjustment.Results: Results showed the full mediation effect of mental health between parenting stress and dyadic adjustment. A multi-group analysis further found that the paths did not differ across mothers and fathers.Discussion: The results suggest that mental health is an important dimension that mediates the relationship between parenting stress and dyadic adjustment in the transition to parenthood.

  5. A price adjustment process in a model of monopolistic competition

    NARCIS (Netherlands)

    Tuinstra, J.

    2004-01-01

    We consider a price adjustment process in a model of monopolistic competition. Firms have incomplete information about the demand structure. When they set a price they observe the amount they can sell at that price and they observe the slope of the true demand curve at that price. With this

  6. Aqua/Aura Updated Inclination Adjust Maneuver Performance Prediction Model

    Science.gov (United States)

    Boone, Spencer

    2017-01-01

    This presentation will discuss the updated Inclination Adjust Maneuver (IAM) performance prediction model that was developed for Aqua and Aura following the 2017 IAM series. This updated model uses statistical regression methods to identify potential long-term trends in maneuver parameters, yielding improved predictions when re-planning past maneuvers. The presentation has been reviewed and approved by Eric Moyer, ESMO Deputy Project Manager.

  7. Generalized Additive Models for Nowcasting Cloud Shading

    Czech Academy of Sciences Publication Activity Database

    Brabec, Marek; Paulescu, M.; Badescu, V.

    2014-01-01

    Roč. 101, March (2014), s. 272-282 ISSN 0038-092X R&D Projects: GA MŠk LD12009 Grant - others:European Cooperation in Science and Technology(XE) COST ES1002 Institutional support: RVO:67985807 Keywords : sunshine number * nowcasting * generalized additive model * Markov chain Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 3.469, year: 2014

  8. Modeling wind adjustment factor and midflame wind speed for Rothermel's surface fire spread model

    Science.gov (United States)

    Patricia L. Andrews

    2012-01-01

    Rothermel's surface fire spread model was developed to use a value for the wind speed that affects surface fire, called midflame wind speed. Models have been developed to adjust 20-ft wind speed to midflame wind speed for sheltered and unsheltered surface fuel. In this report, Wind Adjustment Factor (WAF) model equations are given, and the BehavePlus fire modeling...

  9. A generalized additive regression model for survival times

    DEFF Research Database (Denmark)

    Scheike, Thomas H.

    2001-01-01

    Additive Aalen model; counting process; disability model; illness-death model; generalized additive models; multiple time-scales; non-parametric estimation; survival data; varying-coefficient models......Additive Aalen model; counting process; disability model; illness-death model; generalized additive models; multiple time-scales; non-parametric estimation; survival data; varying-coefficient models...

  10. Shutdown potential adjustment of modified carbene adducts as additives for lithium ion battery electrolytes

    Science.gov (United States)

    Janssen, Pia; Streipert, Benjamin; Krafft, Roman; Murmann, Patrick; Wagner, Ralf; Lewis-Alleyne, Lesley; Röschenthaler, Gerd-Volker; Winter, Martin; Cekic-Laskovic, Isidora

    2017-11-01

    To improve the intrinsic safety of lithium ion batteries (LIBs) by preventing cells from a thermal runaway, we studied two carbene adduct electrolyte additives. The recently synthesized compounds (1,3-dimethylimidazolidin-2-μm-trifluoroborate (NHC-BF3) and 1,3-dimethylimidazolidin-2-μm-tetrafluorotrifluoromethylphosphate (NHC-PF4CF3)) were investigated on LiNi1/3Co1/3Mn1/3O2 (NMC111) electrodes in Li metal and Li-ion cell setups as overcharge protection shutdown additives in 1M LiPF6 in EC:DEC (3:7, by wt.) electrolyte. By varying the NHC-ligand (-BF3, -PF5, -PF4CF3) in the molecule, the shutdown potential of the investigated carbene adduct electrolyte additives can be tailored for specific applications with different cut-off potentials. NHC-BF3 was identified as a promising candidate for the application with NMC111 electrodes up to 4.4 V vs. Li/Li+, whereas the carbene adduct NHC-PF4CF3 is ideal for the high-voltage application with the NMC-based electrode up to 4.6 V vs. Li/Li+. Next to electrochemical investigations in NMC111/Li and NMC111/graphite cells, Atomic Force Microscopy (AFM) and X-Ray Photoelectron Spectroscopy (XPS) were performed to verify the presence of a decomposition layer on the cathode, responsible for the shutdown effect. Furthermore, it has been proven that the investigated electrolyte additives have no influence on the cell performance under normal conditions in both, Li metal and Li-ion cell setups.

  11. Additive risk survival model with microarray data

    Directory of Open Access Journals (Sweden)

    Huang Jian

    2007-06-01

    Full Text Available Abstract Background Microarray techniques survey gene expressions on a global scale. Extensive biomedical studies have been designed to discover subsets of genes that are associated with survival risks for diseases such as lymphoma and construct predictive models using those selected genes. In this article, we investigate simultaneous estimation and gene selection with right censored survival data and high dimensional gene expression measurements. Results We model the survival time using the additive risk model, which provides a useful alternative to the proportional hazards model and is adopted when the absolute effects, instead of the relative effects, of multiple predictors on the hazard function are of interest. A Lasso (least absolute shrinkage and selection operator type estimate is proposed for simultaneous estimation and gene selection. Tuning parameter is selected using the V-fold cross validation. We propose Leave-One-Out cross validation based methods for evaluating the relative stability of individual genes and overall prediction significance. Conclusion We analyze the MCL and DLBCL data using the proposed approach. A small number of probes represented on the microarrays are identified, most of which have sound biological implications in lymphoma development. The selected probes are relatively stable and the proposed approach has overall satisfactory prediction power.

  12. Network reconstruction using nonparametric additive ODE models.

    Science.gov (United States)

    Henderson, James; Michailidis, George

    2014-01-01

    Network representations of biological systems are widespread and reconstructing unknown networks from data is a focal problem for computational biologists. For example, the series of biochemical reactions in a metabolic pathway can be represented as a network, with nodes corresponding to metabolites and edges linking reactants to products. In a different context, regulatory relationships among genes are commonly represented as directed networks with edges pointing from influential genes to their targets. Reconstructing such networks from data is a challenging problem receiving much attention in the literature. There is a particular need for approaches tailored to time-series data and not reliant on direct intervention experiments, as the former are often more readily available. In this paper, we introduce an approach to reconstructing directed networks based on dynamic systems models. Our approach generalizes commonly used ODE models based on linear or nonlinear dynamics by extending the functional class for the functions involved from parametric to nonparametric models. Concomitantly we limit the complexity by imposing an additive structure on the estimated slope functions. Thus the submodel associated with each node is a sum of univariate functions. These univariate component functions form the basis for a novel coupling metric that we define in order to quantify the strength of proposed relationships and hence rank potential edges. We show the utility of the method by reconstructing networks using simulated data from computational models for the glycolytic pathway of Lactocaccus Lactis and a gene network regulating the pluripotency of mouse embryonic stem cells. For purposes of comparison, we also assess reconstruction performance using gene networks from the DREAM challenges. We compare our method to those that similarly rely on dynamic systems models and use the results to attempt to disentangle the distinct roles of linearity, sparsity, and derivative

  13. Computational Process Modeling for Additive Manufacturing (OSU)

    Science.gov (United States)

    Bagg, Stacey; Zhang, Wei

    2015-01-01

    Powder-Bed Additive Manufacturing (AM) through Direct Metal Laser Sintering (DMLS) or Selective Laser Melting (SLM) is being used by NASA and the Aerospace industry to "print" parts that traditionally are very complex, high cost, or long schedule lead items. The process spreads a thin layer of metal powder over a build platform, then melts the powder in a series of welds in a desired shape. The next layer of powder is applied, and the process is repeated until layer-by-layer, a very complex part can be built. This reduces cost and schedule by eliminating very complex tooling and processes traditionally used in aerospace component manufacturing. To use the process to print end-use items, NASA seeks to understand SLM material well enough to develop a method of qualifying parts for space flight operation. Traditionally, a new material process takes many years and high investment to generate statistical databases and experiential knowledge, but computational modeling can truncate the schedule and cost -many experiments can be run quickly in a model, which would take years and a high material cost to run empirically. This project seeks to optimize material build parameters with reduced time and cost through modeling.

  14. U.S. immigrants' labor market adjustment: additional human capital investment and earnings growth.

    Science.gov (United States)

    Akresh, Ilana Redstone

    2007-11-01

    New Immigrant Survey-Pilot data are used to address the long-standing debate over whether immigrants to the United States assimilate economically. Using panel data and an individual fixed-effect specification, I find evidence indicating rapid economic assimilation, on the order of an average increase in earnings of 12%-13% during the 12-month survey period. Results indicate partial support for Duleep and Regets' Immigrant Human Capital Investment (IHCI) model, indicating an inverse relationship between initial earnings and earnings growth and showing some evidence of the expected interaction between skill transferability and skill level when predicting human capital investment decisions. Having more years of education, English proficiency, and lower earnings at the baseline are associated with a higher probability of enrolling informal school in the United States. Overall, findings suggest substantial economic integration within the first year after establishing permanent residency.

  15. A Developmental Sequence Model to University Adjustment of International Undergraduate Students

    OpenAIRE

    Chavoshi, Saeid; Wintre, Maxine Gallander; Dentakos, Stella; Wright, Lorna

    2017-01-01

    The current study proposes a Developmental Sequence Model to University Adjustment and uses a multifaceted measure, including academic, social and psychological adjustment, to examine factors predictive of undergraduate international student adjustment. A hierarchic regression model is carried out on the Student Adaptation to College Questionnaire to examine theoretically pertinent predictors arranged in a developmental sequence in determining adjustment outcomes. This model...

  16. When there is more than a cleft: psychological adjustment when a cleft is associated with an additional condition.

    Science.gov (United States)

    Feragen, Kristin Billaud; Stock, Nicola Marie

    2014-01-01

    In spite of studies reporting a relatively high frequency of additional conditions in children with a cleft lip and/or cleft palate (CL/P), almost no research has focused on this clinically important subgroup. The objective of this study was to compare psychosocial adjustment in children with CL/P with and without an additional condition. Cross-sectional data based on routine psychological assessments at age 10 years, with comparisons to national reference groups. Centralized treatment, Norway. Two hundred five children with CL/P (participation rate: 80.1%) from three consecutive birth cohorts. The Strengths and Difficulties Questionnaire (self-report and parent report) and the Child Experience Questionnaire (self-report). Eighty-one children (39.5%) were identified as having at least one condition in addition to the cleft. These children reported significantly more psychosocial difficulties than children with a cleft alone. Differences between specific conditions were minor. Children with a cleft alone (n = 124) reported mean scores that were comparable to those reported by the reference group. There were no differences in adjustment between children with a visible versus a non-visible cleft. The present study highlights the need for research to be conducted in children with CL/P who have additional conditions to provide better knowledge and clinical care for a potentially vulnerable subgroup of children and their parents.

  17. Emotional closeness to parents and grandparents: A moderated mediation model predicting adolescent adjustment.

    Science.gov (United States)

    Attar-Schwartz, Shalhevet

    2015-09-01

    Warm and emotionally close relationships with parents and grandparents have been found in previous studies to be linked with better adolescent adjustment. The present study, informed by Family Systems Theory and Intergenerational Solidarity Theory, uses a moderated mediation model analyzing the contribution of the dynamics of these intergenerational relationships to adolescent adjustment. Specifically, it examines the mediating role of emotional closeness to the closest grandparent in the relationship between emotional closeness to a parent (the offspring of the closest grandparent) and adolescent adjustment difficulties. The model also examines the moderating role of emotional closeness to parents in the relationship between emotional closeness to grandparents and adjustment difficulties. The study was based on a sample of 1,405 Jewish Israeli secondary school students (ages 12-18) who completed a structured questionnaire. It was found that emotional closeness to the closest grandparent was more strongly associated with reduced adjustment difficulties among adolescents with higher levels of emotional closeness to their parents. In addition, adolescent adjustment and emotional closeness to parents was partially mediated by emotional closeness to grandparents. Examining the family conditions under which adolescents' relationships with grandparents is stronger and more beneficial for them can help elucidate variations in grandparent-grandchild ties and expand our understanding of the mechanisms that shape child outcomes. (c) 2015 APA, all rights reserved).

  18. Model for Adjustment of Aggregate Forecasts using Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Taracena–Sanz L. F.

    2010-07-01

    Full Text Available This research suggests a contribution in the implementation of forecasting models. The proposed model is developed with the aim to fit the projection of demand to surroundings of firms, and this is based on three considerations that cause that in many cases the forecasts of the demand are different from reality, such as: 1 one of the problems most difficult to model in the forecasts is the uncertainty related to the information available; 2 the methods traditionally used by firms for the projection of demand mainly are based on past behavior of the market (historical demand; and 3 these methods do not consider in their analysis the factors that are influencing so that the observed behaviour occurs. Therefore, the proposed model is based on the implementation of Fuzzy Logic, integrating the main variables that affect the behavior of market demand, and which are not considered in the classical statistical methods. The model was applied to a bottling of carbonated beverages, and with the adjustment of the projection of demand a more reliable forecast was obtained.

  19. Risk-adjusted models for adverse obstetric outcomes and variation in risk-adjusted outcomes across hospitals.

    Science.gov (United States)

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

    2013-11-01

    Regulatory bodies and insurers evaluate hospital quality using obstetrical outcomes, however meaningful comparisons should take preexisting patient characteristics into account. Furthermore, if risk-adjusted outcomes are consistent within a hospital, fewer measures and resources would be needed to assess obstetrical quality. Our objective was to establish risk-adjusted models for 5 obstetric outcomes and assess hospital performance across these outcomes. We studied a cohort of 115,502 women and their neonates born in 25 hospitals in the United States from March 2008 through February 2011. Hospitals were ranked according to their unadjusted and risk-adjusted frequency of venous thromboembolism, postpartum hemorrhage, peripartum infection, severe perineal laceration, and a composite neonatal adverse outcome. Correlations between hospital risk-adjusted outcome frequencies were assessed. Venous thromboembolism occurred too infrequently (0.03%; 95% confidence interval [CI], 0.02-0.04%) for meaningful assessment. Other outcomes occurred frequently enough for assessment (postpartum hemorrhage, 2.29%; 95% CI, 2.20-2.38, peripartum infection, 5.06%; 95% CI, 4.93-5.19, severe perineal laceration at spontaneous vaginal delivery, 2.16%; 95% CI, 2.06-2.27, neonatal composite, 2.73%; 95% CI, 2.63-2.84). Although there was high concordance between unadjusted and adjusted hospital rankings, several individual hospitals had an adjusted rank that was substantially different (as much as 12 rank tiers) than their unadjusted rank. None of the correlations between hospital-adjusted outcome frequencies was significant. For example, the hospital with the lowest adjusted frequency of peripartum infection had the highest adjusted frequency of severe perineal laceration. Evaluations based on a single risk-adjusted outcome cannot be generalized to overall hospital obstetric performance. Copyright © 2013 Mosby, Inc. All rights reserved.

  20. An Additive-Multiplicative Cox-Aalen Regression Model

    DEFF Research Database (Denmark)

    Scheike, Thomas H.; Zhang, Mei-Jie

    2002-01-01

    Aalen model; additive risk model; counting processes; Cox regression; survival analysis; time-varying effects......Aalen model; additive risk model; counting processes; Cox regression; survival analysis; time-varying effects...

  1. The protective action decision model: theoretical modifications and additional evidence.

    Science.gov (United States)

    Lindell, Michael K; Perry, Ronald W

    2012-04-01

    The Protective Action Decision Model (PADM) is a multistage model that is based on findings from research on people's responses to environmental hazards and disasters. The PADM integrates the processing of information derived from social and environmental cues with messages that social sources transmit through communication channels to those at risk. The PADM identifies three critical predecision processes (reception, attention, and comprehension of warnings or exposure, attention, and interpretation of environmental/social cues)--that precede all further processing. The revised model identifies three core perceptions--threat perceptions, protective action perceptions, and stakeholder perceptions--that form the basis for decisions about how to respond to an imminent or long-term threat. The outcome of the protective action decision-making process, together with situational facilitators and impediments, produces a behavioral response. In addition to describing the revised model and the research on which it is based, this article describes three applications (development of risk communication programs, evacuation modeling, and adoption of long-term hazard adjustments) and identifies some of the research needed to address unresolved issues. © 2011 Society for Risk Analysis.

  2. A Developmental Sequence Model to University Adjustment of International Undergraduate Students

    Science.gov (United States)

    Chavoshi, Saeid; Wintre, Maxine Gallander; Dentakos, Stella; Wright, Lorna

    2017-01-01

    The current study proposes a Developmental Sequence Model to University Adjustment and uses a multifaceted measure, including academic, social and psychological adjustment, to examine factors predictive of undergraduate international student adjustment. A hierarchic regression model is carried out on the Student Adaptation to College Questionnaire…

  3. Disaster Hits Home: A Model of Displaced Family Adjustment after Hurricane Katrina

    Science.gov (United States)

    Peek, Lori; Morrissey, Bridget; Marlatt, Holly

    2011-01-01

    The authors explored individual and family adjustment processes among parents (n = 30) and children (n = 55) who were displaced to Colorado after Hurricane Katrina. Drawing on in-depth interviews with 23 families, this article offers an inductive model of displaced family adjustment. Four stages of family adjustment are presented in the model: (a)…

  4. Adjustment costs in a two-capital growth model

    Czech Academy of Sciences Publication Activity Database

    Duczynski, Petr

    2002-01-01

    Roč. 26, č. 5 (2002), s. 837-850 ISSN 0165-1889 R&D Projects: GA AV ČR KSK9058117 Institutional research plan: CEZ:AV0Z7085904 Keywords : adjustment costs * capital mobility * convergence * human capital Subject RIV: AH - Economics Impact factor: 0.738, year: 2002

  5. Detectability adjusted count models of songbird abundance: Chapter 6

    Science.gov (United States)

    2011-01-01

    Sagebrush (Artemisia spp.) steppe ecosystems have experienced recent changes resulting not only in the loss of habitat but also fragmentation and degradation of remaining habitats. As a result, sagebrush-obligate and sagebrush associated songbird populations have experienced population declines over the past several decades. We examined landscape-scale responses in occupancy and abundance for six focal songbird species at 318 survey sites across the Wyoming Basins Ecoregional Assessment (WBEA) area. Occupancy and abundance models were fit for each species using datasets developed at multiple moving window extents to assess landscape-scale relationships between abiotic, habitat, and anthropogenic factors. Anthropogenic factors had less influence on species occupancy or abundance than abiotic and habitat factors. Sagebrush measures were strong predictors of occurrence for sagebrush-obligate species, such as Brewer’s sparrows (Spizella breweri), sage sparrows (Amphispiza belli) and sage thrashers (Oreoscoptes montanus), as well as green-tailed towhees (Pipilo chlorurus), a species associated with mountain shrub communities. Occurrence for lark sparrows (Chondestes grammacus) and vesper sparrows (Pooecetes gramineus), considered shrub steppe-associated species, was also related to big sagebrush communities, but at large spatial extents. Although relationships between anthropogenic variables and occurrence were weak for most species, the consistent relationship with sagebrush habitat variables suggests direct habitat loss and not edge or additional fragmentation effects are causing declines in the avifauna examined in the WBEA area. Thus, natural and anthropogenic disturbances that result in loss of critical habitats are the biggest threats to these species. We applied our models spatially across the WBEA area to identify and prioritize key areas for conservation.

  6. Using Green's Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model

    Science.gov (United States)

    Brix, H.; Menemenlis, D.; Hill, C.; Dutkiewicz, S.; Jahn, O.; Wang, D.; Bowman, K.; Zhang, H.

    2015-11-01

    exchange parameter differs by only 3% from the baseline value and has little impact (- 0.1 %) on the cost function. The particulate inorganic to organic carbon ratio was increased more than threefold and reduced the cost function by 22% relative to the baseline integration, indicating a significant influence of biology on air-sea gas exchange. The largest contribution to cost reduction (35%) comes from the adjustment of initial conditions. In addition to reducing biases relative to observations, the adjusted simulation exhibits smaller model drift than the baseline. We estimate drift by integrating the model with repeated 2009 atmospheric forcing for seven years and find a volume-weighted drift reduction of, for example, 12.5% for nitrate and 30% for oxygen in the top 300 m. Although there remain several regions with large model-data discrepancies, for example, overly strong carbon uptake in the Southern Ocean, the adjusted simulation is a first step towards a more accurate representation of the ocean carbon cycle at high spatial and temporal resolution.

  7. Modeling of an Adjustable Beam Solid State Light

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of a computational model of a prototype variable beam light source using optical modeling software, Zemax OpticStudio ®. The...

  8. Utilizing Visual Effects Software for Efficient and Flexible Isostatic Adjustment Modelling

    Science.gov (United States)

    Meldgaard, A.; Nielsen, L.; Iaffaldano, G.

    2017-12-01

    The isostatic adjustment signal generated by transient ice sheet loading is an important indicator of past ice sheet extent and the rheological constitution of the interior of the Earth. Finite element modelling has proved to be a very useful tool in these studies. We present a simple numerical model for 3D visco elastic Earth deformation and a new approach to the design of such models utilizing visual effects software designed for the film and game industry. The software package Houdini offers an assortment of optimized tools and libraries which greatly facilitate the creation of efficient numerical algorithms. In particular, we make use of Houdini's procedural work flow, the SIMD programming language VEX, Houdini's sparse matrix creation and inversion libraries, an inbuilt tetrahedralizer for grid creation, and the user interface, which facilitates effortless manipulation of 3D geometry. We mitigate many of the time consuming steps associated with the authoring of efficient algorithms from scratch while still keeping the flexibility that may be lost with the use of commercial dedicated finite element programs. We test the efficiency of the algorithm by comparing simulation times with off-the-shelf solutions from the Abaqus software package. The algorithm is tailored for the study of local isostatic adjustment patterns, in close vicinity to present ice sheet margins. In particular, we wish to examine possible causes for the considerable spatial differences in the uplift magnitude which are apparent from field observations in these areas. Such features, with spatial scales of tens of kilometres, are not resolvable with current global isostatic adjustment models, and may require the inclusion of local topographic features. We use the presented algorithm to study a near field area where field observations are abundant, namely, Disko Bay in West Greenland with the intention of constraining Earth parameters and ice thickness. In addition, we assess how local

  9. Maternal Working Models of Attachment, Marital Adjustment, and the Parent-Child Relationship.

    Science.gov (United States)

    Eiden, Rina Das; And Others

    1995-01-01

    Examined the connection between maternal working models, marital adjustment, and parent-child relationship among 45 mothers and their 16- to 62-month-old children. Found that maternal working models were related to the quality of mother-child interactions and child security, as well as a significant relationship between marital adjustment and…

  10. Process chain modeling and selection in an additive manufacturing context

    DEFF Research Database (Denmark)

    Thompson, Mary Kathryn; Stolfi, Alessandro; Mischkot, Michael

    2016-01-01

    This paper introduces a new two-dimensional approach to modeling manufacturing process chains. This approach is used to consider the role of additive manufacturing technologies in process chains for a part with micro scale features and no internal geometry. It is shown that additive manufacturing...... evolving fields like additive manufacturing....

  11. An additive factor analysis of the effect of sub-anaesthetic doses of nitrous oxide on information processing: evidence for an impairment of the motor adjustment stage.

    Science.gov (United States)

    Courtière, Alain; Hardouin, Jeannine; Vidal, Franck; Possamaï, Camille-Aimé; Hasbroucq, Thierry

    2003-02-01

    Nitrous oxide (N(2)O) inhalation, at subanaesthetic concentrations, impairs choice reaction time (RT). However, the functional locus of this effect remains to be ascertained. In the present study, this issue was investigated by applying the additive factor logic to the RTs of rats performing a visuo-motor task. The task consisted of either a left-side or a right-side body displacement to a visual stimulus displayed in either the left or right hemispace. The experimental design involved the manipulation of two task factors (stimulus luminance and foreperiod duration) the effects of which are additive on RT. Inhaled N(2)O (from 0% to 60%) was varied as the third factor of the design. N(2)O prolonged RT in a dose-dependent manner and this effect was additive with that of stimulus luminance, whilst it interacted with that of foreperiod duration. Moreover, at low concentrations (10-20%), N(2)O abolished the effect of foreperiod, possibly through a disturbance of time estimation processes, whereas at higher concentrations (30-40%) N(2)O enhanced the effect of foreperiod, probably by slowing down motor processes. Movement time (MT) was decreased by N(2)O at 20-40%. The present data provide evidence that N(2)O impairs information processing by altering at least the stage of motor adjustment. In addition, N(2)O spares the sensory processes implemented during the stimulus preprocessing stage. A subsidiary result is that at some concentrations, N(2)O displays opposite effects on reaction time and movement time. These results demonstrate that the additive factor method constitutes a powerful new tool for studying the pharmacology of information processing in animal models.

  12. Lower-order effects adjustment in quantitative traits model-based multifactor dimensionality reduction.

    Science.gov (United States)

    Mahachie John, Jestinah M; Cattaert, Tom; Lishout, François Van; Gusareva, Elena S; Steen, Kristel Van

    2012-01-01

    Identifying gene-gene interactions or gene-environment interactions in studies of human complex diseases remains a big challenge in genetic epidemiology. An additional challenge, often forgotten, is to account for important lower-order genetic effects. These may hamper the identification of genuine epistasis. If lower-order genetic effects contribute to the genetic variance of a trait, identified statistical interactions may simply be due to a signal boost of these effects. In this study, we restrict attention to quantitative traits and bi-allelic SNPs as genetic markers. Moreover, our interaction study focuses on 2-way SNP-SNP interactions. Via simulations, we assess the performance of different corrective measures for lower-order genetic effects in Model-Based Multifactor Dimensionality Reduction epistasis detection, using additive and co-dominant coding schemes. Performance is evaluated in terms of power and familywise error rate. Our simulations indicate that empirical power estimates are reduced with correction of lower-order effects, likewise familywise error rates. Easy-to-use automatic SNP selection procedures, SNP selection based on "top" findings, or SNP selection based on p-value criterion for interesting main effects result in reduced power but also almost zero false positive rates. Always accounting for main effects in the SNP-SNP pair under investigation during Model-Based Multifactor Dimensionality Reduction analysis adequately controls false positive epistasis findings. This is particularly true when adopting a co-dominant corrective coding scheme. In conclusion, automatic search procedures to identify lower-order effects to correct for during epistasis screening should be avoided. The same is true for procedures that adjust for lower-order effects prior to Model-Based Multifactor Dimensionality Reduction and involve using residuals as the new trait. We advocate using "on-the-fly" lower-order effects adjusting when screening for SNP-SNP interactions

  13. Circumplex and Spherical Models for Child School Adjustment and Competence.

    Science.gov (United States)

    Schaefer, Earl S.; Edgerton, Marianna

    The goal of this study is to broaden the scope of a conceptual model for child behavior by analyzing constructs relevant to cognition, conation, and affect. Two samples were drawn from school populations. For the first sample, 28 teachers from 8 rural, suburban, and urban schools rated 193 kindergarten children. Each teacher rated up to eight…

  14. R.M. Solow Adjusted Model of Economic Growth

    Directory of Open Access Journals (Sweden)

    Ion Gh. Rosca

    2007-05-01

    The analysis part of the model is based on the study of the equilibrium to the continuous case with some interpretations of the discreet one, by using the state diagram. The optimization problem at the economic level is also used; it is built up of a specified number of representative consumers and firms in order to reveal the interaction between these elements.

  15. An Additive-Multiplicative Restricted Mean Residual Life Model

    DEFF Research Database (Denmark)

    Mansourvar, Zahra; Martinussen, Torben; Scheike, Thomas H.

    2016-01-01

    The mean residual life measures the expected remaining life of a subject who has survived up to a particular time. When survival time distribution is highly skewed or heavy tailed, the restricted mean residual life must be considered. In this paper, we propose an additive-multiplicative restricted...... mean residual life model to study the association between the restricted mean residual life function and potential regression covariates in the presence of right censoring. This model extends the proportional mean residual life model using an additive model as its covariate dependent baseline....... For the suggested model, some covariate effects are allowed to be time-varying. To estimate the model parameters, martingale estimating equations are developed, and the large sample properties of the resulting estimators are established. In addition, to assess the adequacy of the model, we investigate a goodness...

  16. An Efficient Bundle Adjustment Model Based on Parallax Parametrization for Environmental Monitoring

    Science.gov (United States)

    Chen, R.; Sun, Y. Y.; Lei, Y.

    2017-12-01

    With the rapid development of Unmanned Aircraft Systems (UAS), more and more research fields have been successfully equipped with this mature technology, among which is environmental monitoring. One difficult task is how to acquire accurate position of ground object in order to reconstruct the scene more accurate. To handle this problem, we combine bundle adjustment method from Photogrammetry with parallax parametrization from Computer Vision to create a new method call APCP (aerial polar-coordinate photogrammetry). One impressive advantage of this method compared with traditional method is that the 3-dimensional point in space is represented using three angles (elevation angle, azimuth angle and parallax angle) rather than the XYZ value. As the basis for APCP, bundle adjustment could be used to optimize the UAS sensors' pose accurately, reconstruct the 3D models of environment, thus serving as the criterion of accurate position for monitoring. To verity the effectiveness of the proposed method, we test on several UAV dataset obtained by non-metric digital cameras with large attitude angles, and we find that our methods could achieve 1 or 2 times better efficiency with no loss of accuracy than traditional ones. For the classical nonlinear optimization of bundle adjustment model based on the rectangular coordinate, it suffers the problem of being seriously dependent on the initial values, making it unable to converge fast or converge to a stable state. On the contrary, APCP method could deal with quite complex condition of UAS when conducting monitoring as it represent the points in space with angles, including the condition that the sequential images focusing on one object have zero parallax angle. In brief, this paper presents the parameterization of 3D feature points based on APCP, and derives a full bundle adjustment model and the corresponding nonlinear optimization problems based on this method. In addition, we analyze the influence of convergence and

  17. Droop Control with an Adjustable Complex Virtual Impedance Loop based on Cloud Model Theory

    DEFF Research Database (Denmark)

    Li, Yan; Shuai, Zhikang; Xu, Qinming

    2016-01-01

    Droop control framework with an adjustable virtual impedance loop is proposed in this paper, which is based on the cloud model theory. The proposed virtual impedance loop includes two terms: a negative virtual resistor and an adjustable virtual inductance. The negative virtual resistor term...

  18. Adjustment problems and maladaptive relational style: a mediational model of sexual coercion in intimate relationships.

    Science.gov (United States)

    Salwen, Jessica K; O'Leary, K Daniel

    2013-07-01

    Four hundred and fifty-three married or cohabitating couples participated in the current study. A meditational model of men's perpetration of sexual coercion within an intimate relationship was examined based on past theories and known correlates of rape and sexual coercion. The latent constructs of adjustment problems and maladaptive relational style were examined. Adjustment problem variables included perceived stress, perceived low social support, and marital discord. Maladaptive relational style variables included psychological aggression, dominance, and jealousy. Sexual coercion was a combined measure of men's reported perpetration and women's reported victimization. As hypothesized, adjustment problems significantly predicted sexual coercion. Within the meditational model, adjustment problems were significantly correlated with maladaptive relational style, and maladaptive relational style significantly predicted sexual coercion. Once maladaptive relational style was introduced as a mediator, adjustment problems no longer significantly predicted sexual coercion. Implications for treatment, limitations, and future research are discussed.

  19. Comprehensive European dietary exposure model (CEDEM) for food additives.

    Science.gov (United States)

    Tennant, David R

    2016-05-01

    European methods for assessing dietary exposures to nutrients, additives and other substances in food are limited by the availability of detailed food consumption data for all member states. A proposed comprehensive European dietary exposure model (CEDEM) applies summary data published by the European Food Safety Authority (EFSA) in a deterministic model based on an algorithm from the EFSA intake method for food additives. The proposed approach can predict estimates of food additive exposure provided in previous EFSA scientific opinions that were based on the full European food consumption database.

  20. Ridge, Lasso and Bayesian additive-dominance genomic models.

    Science.gov (United States)

    Azevedo, Camila Ferreira; de Resende, Marcos Deon Vilela; E Silva, Fabyano Fonseca; Viana, José Marcelo Soriano; Valente, Magno Sávio Ferreira; Resende, Márcio Fernando Ribeiro; Muñoz, Patricio

    2015-08-25

    A complete approach for genome-wide selection (GWS) involves reliable statistical genetics models and methods. Reports on this topic are common for additive genetic models but not for additive-dominance models. The objective of this paper was (i) to compare the performance of 10 additive-dominance predictive models (including current models and proposed modifications), fitted using Bayesian, Lasso and Ridge regression approaches; and (ii) to decompose genomic heritability and accuracy in terms of three quantitative genetic information sources, namely, linkage disequilibrium (LD), co-segregation (CS) and pedigree relationships or family structure (PR). The simulation study considered two broad sense heritability levels (0.30 and 0.50, associated with narrow sense heritabilities of 0.20 and 0.35, respectively) and two genetic architectures for traits (the first consisting of small gene effects and the second consisting of a mixed inheritance model with five major genes). G-REML/G-BLUP and a modified Bayesian/Lasso (called BayesA*B* or t-BLASSO) method performed best in the prediction of genomic breeding as well as the total genotypic values of individuals in all four scenarios (two heritabilities x two genetic architectures). The BayesA*B*-type method showed a better ability to recover the dominance variance/additive variance ratio. Decomposition of genomic heritability and accuracy revealed the following descending importance order of information: LD, CS and PR not captured by markers, the last two being very close. Amongst the 10 models/methods evaluated, the G-BLUP, BAYESA*B* (-2,8) and BAYESA*B* (4,6) methods presented the best results and were found to be adequate for accurately predicting genomic breeding and total genotypic values as well as for estimating additive and dominance in additive-dominance genomic models.

  1. On the compensation between cloud feedback and cloud adjustment in climate models

    Science.gov (United States)

    Chung, Eui-Seok; Soden, Brian J.

    2018-02-01

    Intermodel compensation between cloud feedback and rapid cloud adjustment has important implications for the range of model-inferred climate sensitivity. Although this negative intermodel correlation exists in both realistic (e.g., coupled ocean-atmosphere models) and idealized (e.g., aqua-planet) model configurations, the compensation appears to be stronger in the latter. The cause of the compensation between feedback and adjustment, and its dependence on model configuration remain poorly understood. In this study, we examine the characteristics of the cloud feedback and adjustment in model simulations with differing complexity, and analyze the causes responsible for their compensation. We show that in all model configurations, the intermodel compensation between cloud feedback and cloud adjustment largely results from offsetting changes in marine boundary-layer clouds. The greater prevalence of these cloud types in aqua-planet models is a likely contributor to the larger correlation between feedback and adjustment in those configurations. It is also shown that differing circulation changes in the aqua-planet configuration of some models act to amplify the intermodel range and sensitivity of the cloud radiative response by about a factor of 2.

  2. Modeling and Control of the Redundant Parallel Adjustment Mechanism on a Deployable Antenna Panel

    Directory of Open Access Journals (Sweden)

    Lili Tian

    2016-10-01

    Full Text Available With the aim of developing multiple input and multiple output (MIMO coupling systems with a redundant parallel adjustment mechanism on the deployable antenna panel, a structural control integrated design methodology is proposed in this paper. Firstly, the modal information from the finite element model of the structure of the antenna panel is extracted, and then the mathematical model is established with the Hamilton principle; Secondly, the discrete Linear Quadratic Regulator (LQR controller is added to the model in order to control the actuators and adjust the shape of the panel. Finally, the engineering practicality of the modeling and control method based on finite element analysis simulation is verified.

  3. Additive Intensity Regression Models in Corporate Default Analysis

    DEFF Research Database (Denmark)

    Lando, David; Medhat, Mamdouh; Nielsen, Mads Stenbo

    2013-01-01

    We consider additive intensity (Aalen) models as an alternative to the multiplicative intensity (Cox) models for analyzing the default risk of a sample of rated, nonfinancial U.S. firms. The setting allows for estimating and testing the significance of time-varying effects. We use a variety...... of model checking techniques to identify misspecifications. In our final model, we find evidence of time-variation in the effects of distance-to-default and short-to-long term debt. Also we identify interactions between distance-to-default and other covariates, and the quick ratio covariate is significant....... None of our macroeconomic covariates are significant....

  4. Steps in the construction and verification of an explanatory model of psychosocial adjustment

    Directory of Open Access Journals (Sweden)

    Arantzazu Rodríguez-Fernández

    2016-06-01

    Full Text Available The aim of the present study was to empirically test an explanatory model of psychosocial adjustment during adolescence, with psychosocial adjustment during this stage being understood as a combination of school adjustment (or school engagement and subjective well-being. According to the hypothetic model, psychosocial adjustment depends on self-concept and resilience, which in turn act as mediators of the influence of perceived social support (from family, peers and teachers on this adjustment. Participants were 1250 secondary school students (638 girls and 612 boys aged between 12 and 15 years (Mean = 13.72; SD = 1.09. The results provided evidence of: (a the influence of all three types of perceived support on subject resilience and self-concept, with perceived family support being particularly important in this respect; (b the influence of the support received from teachers on school adjustment and support received from the family on psychological wellbeing; and (c the absence of any direct influence of peer support on psychosocial adjustment, although indirect influence was observed through the psychological variables studied. These results are discussed from an educational perspective and in terms of future research

  5. Steps in the construction and verification of an explanatory model of psychosocial adjustment

    Directory of Open Access Journals (Sweden)

    Arantzazu Rodríguez-Fernández

    2016-06-01

    Full Text Available The aim of the present study was to empirically test an explanatory model of psychosocial adjustment during adolescence, with psychosocial adjustment during this stage being understood as a combination of school adjustment (or school engagement and subjective well-being. According to the hypothetic model, psychosocial adjustment depends on self-concept and resilience, which in turn act as mediators of the influence of perceived social support (from family, peers and teachers on this adjustment. Participants were 1250 secondary school students (638 girls and 612 boys aged between 12 and 15 years (Mean = 13.72; SD = 1.09. The results provided evidence of: (a the influence of all three types of perceived support on subject resilience and self-concept, with perceived family support being particularly important in this respect; (b the influence of the support received from teachers on school adjustment and support received from the family on psychological wellbeing; and (c the absence of any direct influence of peer support on psychosocial adjustment, although indirect influence was observed through the psychological variables studied. These results are discussed from an educational perspective and in terms of future research.

  6. Modeling Errors in Daily Precipitation Measurements: Additive or Multiplicative?

    Science.gov (United States)

    Tian, Yudong; Huffman, George J.; Adler, Robert F.; Tang, Ling; Sapiano, Matthew; Maggioni, Viviana; Wu, Huan

    2013-01-01

    The definition and quantification of uncertainty depend on the error model used. For uncertainties in precipitation measurements, two types of error models have been widely adopted: the additive error model and the multiplicative error model. This leads to incompatible specifications of uncertainties and impedes intercomparison and application.In this letter, we assess the suitability of both models for satellite-based daily precipitation measurements in an effort to clarify the uncertainty representation. Three criteria were employed to evaluate the applicability of either model: (1) better separation of the systematic and random errors; (2) applicability to the large range of variability in daily precipitation; and (3) better predictive skills. It is found that the multiplicative error model is a much better choice under all three criteria. It extracted the systematic errors more cleanly, was more consistent with the large variability of precipitation measurements, and produced superior predictions of the error characteristics. The additive error model had several weaknesses, such as non constant variance resulting from systematic errors leaking into random errors, and the lack of prediction capability. Therefore, the multiplicative error model is a better choice.

  7. Covariate selection for the semiparametric additive risk model

    DEFF Research Database (Denmark)

    Martinussen, Torben; Scheike, Thomas

    2009-01-01

    This paper considers covariate selection for the additive hazards model. This model is particularly simple to study theoretically and its practical implementation has several major advantages to the similar methodology for the proportional hazards model. One complication compared...... and study their large sample properties for the situation where the number of covariates p is smaller than the number of observations. We also show that the adaptive Lasso has the oracle property. In many practical situations, it is more relevant to tackle the situation with large p compared with the number...... of observations. We do this by studying the properties of the so-called Dantzig selector in the setting of the additive risk model. Specifically, we establish a bound on how close the solution is to a true sparse signal in the case where the number of covariates is large. In a simulation study, we also compare...

  8. Improving a mother to child HIV transmission programme through health system redesign: quality improvement, protocol adjustment and resource addition.

    Directory of Open Access Journals (Sweden)

    Michele S Youngleson

    Full Text Available BACKGROUND: Health systems that deliver prevention of mother to child transmission (PMTCT services in low and middle income countries continue to underperform, resulting in thousands of unnecessary HIV infections of newborns each year. We used a combination of approaches to health systems strengthening to reduce transmission of HIV from mother to infant in a multi-facility public health system in South Africa. METHODOLOGY/PRINCIPAL FINDINGS: All primary care sites and specialized birthing centers in a resource constrained sub-district of Cape Metro District, South Africa, were enrolled in a quality improvement (QI programme. All pregnant women receiving antenatal, intrapartum and postnatal infant care in the sub-district between January 2006 and March 2009 were included in the intervention that had a prototype-innovation phase and a rapid spread phase. System changes were introduced to help frontline healthcare workers to identify and improve performance gaps at each step of the PMTCT pathway. Improvement was facilitated and spread through the use of a Breakthrough Series Collaborative that accelerated learning and the spread of successful changes. Protocol changes and additional resources were introduced by provincial and municipal government. The proportion of HIV-exposed infants testing positive declined from 7.6% to 5%. Key intermediate PMTCT processes improved (antenatal AZT increased from 74% to 86%, PMTCT clients on HAART at the time of labour increased from 10% to 25%, intrapartum AZT increased from 43% to 84%, and postnatal HIV testing from 79% to 95% compared to baseline. CONCLUSIONS/SIGNIFICANCE: System improvement methods, protocol changes and addition/reallocation of resources contributed to improved PMTCT processes and outcomes in a resource constrained setting. The intervention requires a clear design, leadership buy-in, building local capacity to use systems improvement methods, and a reliable data system. A systems improvement

  9. Modeling uranium transport in acidic contaminated groundwater with base addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Institute of Tibetan Plateau Research, Chinese Academy of Sciences; Luo, Wensui [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Brooks, Scott C [ORNL; Watson, David B [ORNL; Jardine, Philip [University of Tennessee, Knoxville (UTK); Gu, Baohua [ORNL

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  10. Modeling uranium transport in acidic contaminated groundwater with base addition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Fan, E-mail: zhangfan@itpcas.ac.cn [Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, P.O. Box 2871, Beijing, 100085 (China); Luo Wensui [Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021 (China); Parker, Jack C. [Institute for a Secure and Sustainable Environment, Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Brooks, Scott C.; Watson, David B. [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Jardine, Philip M. [Biosystems Engineering and Soil Science Department, University of Tennessee, Knoxville, TN 37996 (United States); Gu Baohua [Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2011-06-15

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  11. Efficient estimation of an additive quantile regression model

    NARCIS (Netherlands)

    Cheng, Y.; de Gooijer, J.G.; Zerom, D.

    2009-01-01

    In this paper two kernel-based nonparametric estimators are proposed for estimating the components of an additive quantile regression model. The first estimator is a computationally convenient approach which can be viewed as a viable alternative to the method of De Gooijer and Zerom (2003). By

  12. Efficient estimation of an additive quantile regression model

    NARCIS (Netherlands)

    Cheng, Y.; de Gooijer, J.G.; Zerom, D.

    2010-01-01

    In this paper two kernel-based nonparametric estimators are proposed for estimating the components of an additive quantile regression model. The first estimator is a computationally convenient approach which can be viewed as a viable alternative to the method of De Gooijer and Zerom (2003). By

  13. Efficient estimation of an additive quantile regression model

    NARCIS (Netherlands)

    Cheng, Y.; de Gooijer, J.G.; Zerom, D.

    2011-01-01

    In this paper, two non-parametric estimators are proposed for estimating the components of an additive quantile regression model. The first estimator is a computationally convenient approach which can be viewed as a more viable alternative to existing kernel-based approaches. The second estimator

  14. The additive hazards model with high-dimensional regressors

    DEFF Research Database (Denmark)

    Martinussen, Torben

    2009-01-01

    This paper considers estimation and prediction in the Aalen additive hazards model in the case where the covariate vector is high-dimensional such as gene expression measurements. Some form of dimension reduction of the covariate space is needed to obtain useful statistical analyses. We study...

  15. Modelling of additive manufacturing processes: a review and classification

    Science.gov (United States)

    Stavropoulos, Panagiotis; Foteinopoulos, Panagis

    2018-03-01

    Additive manufacturing (AM) is a very promising technology; however, there are a number of open issues related to the different AM processes. The literature on modelling the existing AM processes is reviewed and classified. A categorization of the different AM processes in process groups, according to the process mechanism, has been conducted and the most important issues are stated. Suggestions are made as to which approach is more appropriate according to the key performance indicator desired to be modelled and a discussion is included as to the way that future modelling work can better contribute to improving today's AM process understanding.

  16. The Psychosocial Adjustment of the Southeast Asian Refugee: An Overview of Empirical Findings and Theoretical Models.

    Science.gov (United States)

    Nicassio, Perry M.

    1985-01-01

    Summarizes clinical and research literature on Southeast Asian refugees' adjustment in the United States and proposes the adoption of theoretical models that may help explain individual differences. Reports that acculturation, learned helplessness, and stress management models appear to aid the conceptualizing of refugee problems and provide a…

  17. Modeling Quality-Adjusted Life Expectancy Loss Resulting from Tobacco Use in the United States

    Science.gov (United States)

    Kaplan, Robert M.; Anderson, John P.; Kaplan, Cameron M.

    2007-01-01

    Purpose: To describe the development of a model for estimating the effects of tobacco use upon Quality Adjusted Life Years (QALYs) and to estimate the impact of tobacco use on health outcomes for the United States (US) population using the model. Method: We obtained estimates of tobacco consumption from 6 years of the National Health Interview…

  18. Single-Index Additive Vector Autoregressive Time Series Models

    KAUST Repository

    LI, YEHUA

    2009-09-01

    We study a new class of nonlinear autoregressive models for vector time series, where the current vector depends on single-indexes defined on the past lags and the effects of different lags have an additive form. A sufficient condition is provided for stationarity of such models. We also study estimation of the proposed model using P-splines, hypothesis testing, asymptotics, selection of the order of the autoregression and of the smoothing parameters and nonlinear forecasting. We perform simulation experiments to evaluate our model in various settings. We illustrate our methodology on a climate data set and show that our model provides more accurate yearly forecasts of the El Niño phenomenon, the unusual warming of water in the Pacific Ocean. © 2009 Board of the Foundation of the Scandinavian Journal of Statistics.

  19. [A structural model for psychosocial adjustment in patients with early breast cancer].

    Science.gov (United States)

    Kim, Hye Young; So, Hyang Sook

    2012-02-01

    This study was done to propose a structural model to explain and predict psychosocial adjustment in patients with early breast cancer and to test the model. The model was based on the Stress-Coping Model of Lazarus and Folkman (1984). Data were collected from February 18 to March 18, 2009. For data analysis, 198 data sets were analyzed using SPSS/WIN12 and AMOS 7.0 version. Social support, uncertainty, symptom experience, and coping had statistically significant direct, indirect and total effects on psychosocial adjustment, and optimism had significant indirect and total effects on psychosocial adjustment. These variables explained 57% of total variance of the psychosocial adjustment in patients with early breast cancer. The results of the study indicate a need to enhance psychosocial adjustment of patients with early breast cancer by providing detailed structured information and various symptom alleviation programs to reduce perceived stresses such as uncertainty and symptom experience. They also suggest the need to establish support systems through participation of medical personnel and families in such programs, and to apply interventions strengthening coping methods to give the patients positive and optimistic beliefs.

  20. Concentration addition, independent action and generalized concentration addition models for mixture effect prediction of sex hormone synthesis in vitro

    DEFF Research Database (Denmark)

    Hadrup, Niels; Taxvig, Camilla; Pedersen, Mikael

    2013-01-01

    and compared to the experimental mixture data. Mixture 1 contained environmental chemicals adjusted in ratio according to human exposure levels. Mixture 2 was a potency adjusted mixture containing five pesticides. Prediction of testosterone effects coincided with the experimental Mixture 1 data. In contrast...... was the predominant but not sole driver of the mixtures, suggesting that one chemical alone was not responsible for the mixture effects. In conclusion, the GCA model seemed to be superior to the CA and IA models for the prediction of testosterone effects. A situation with chemicals exerting opposing effects...

  1. Conference Innovations in Derivatives Market : Fixed Income Modeling, Valuation Adjustments, Risk Management, and Regulation

    CERN Document Server

    Grbac, Zorana; Scherer, Matthias; Zagst, Rudi

    2016-01-01

    This book presents 20 peer-reviewed chapters on current aspects of derivatives markets and derivative pricing. The contributions, written by leading researchers in the field as well as experienced authors from the financial industry, present the state of the art in: • Modeling counterparty credit risk: credit valuation adjustment, debit valuation adjustment, funding valuation adjustment, and wrong way risk. • Pricing and hedging in fixed-income markets and multi-curve interest-rate modeling. • Recent developments concerning contingent convertible bonds, the measuring of basis spreads, and the modeling of implied correlations. The recent financial crisis has cast tremendous doubts on the classical view on derivative pricing. Now, counterparty credit risk and liquidity issues are integral aspects of a prudent valuation procedure and the reference interest rates are represented by a multitude of curves according to their different periods and maturities. A panel discussion included in the book (featuring D...

  2. Just Another Gibbs Additive Modeler: Interfacing JAGS and mgcv

    Directory of Open Access Journals (Sweden)

    Simon N. Wood

    2016-12-01

    Full Text Available The BUGS language offers a very flexible way of specifying complex statistical models for the purposes of Gibbs sampling, while its JAGS variant offers very convenient R integration via the rjags package. However, including smoothers in JAGS models can involve some quite tedious coding, especially for multivariate or adaptive smoothers. Further, if an additive smooth structure is required then some care is needed, in order to centre smooths appropriately, and to find appropriate starting values. R package mgcv implements a wide range of smoothers, all in a manner appropriate for inclusion in JAGS code, and automates centring and other smooth setup tasks. The purpose of this note is to describe an interface between mgcv and JAGS, based around an R function, jagam, which takes a generalized additive model (GAM as specified in mgcv and automatically generates the JAGS model code and data required for inference about the model via Gibbs sampling. Although the auto-generated JAGS code can be run as is, the expectation is that the user would wish to modify it in order to add complex stochastic model components readily specified in JAGS. A simple interface is also provided for visualisation and further inference about the estimated smooth components using standard mgcv functionality. The methods described here will be un-necessarily inefficient if all that is required is fully Bayesian inference about a standard GAM, rather than the full flexibility of JAGS. In that case the BayesX package would be more efficient.

  3. Adjusting a cancer mortality-prediction model for disease status-related eligibility criteria

    Directory of Open Access Journals (Sweden)

    Kimmel Marek

    2011-05-01

    Full Text Available Abstract Background Volunteering participants in disease studies tend to be healthier than the general population partially due to specific enrollment criteria. Using modeling to accurately predict outcomes of cohort studies enrolling volunteers requires adjusting for the bias introduced in this way. Here we propose a new method to account for the effect of a specific form of healthy volunteer bias resulting from imposing disease status-related eligibility criteria, on disease-specific mortality, by explicitly modeling the length of the time interval between the moment when the subject becomes ineligible for the study, and the outcome. Methods Using survival time data from 1190 newly diagnosed lung cancer patients at MD Anderson Cancer Center, we model the time from clinical lung cancer diagnosis to death using an exponential distribution to approximate the length of this interval for a study where lung cancer death serves as the outcome. Incorporating this interval into our previously developed lung cancer risk model, we adjust for the effect of disease status-related eligibility criteria in predicting the number of lung cancer deaths in the control arm of CARET. The effect of the adjustment using the MD Anderson-derived approximation is compared to that based on SEER data. Results Using the adjustment developed in conjunction with our existing lung cancer model, we are able to accurately predict the number of lung cancer deaths observed in the control arm of CARET. Conclusions The resulting adjustment was accurate in predicting the lower rates of disease observed in the early years while still maintaining reasonable prediction ability in the later years of the trial. This method could be used to adjust for, or predict the duration and relative effect of any possible biases related to disease-specific eligibility criteria in modeling studies of volunteer-based cohorts.

  4. Estimating classification images with generalized linear and additive models.

    Science.gov (United States)

    Knoblauch, Kenneth; Maloney, Laurence T

    2008-12-22

    Conventional approaches to modeling classification image data can be described in terms of a standard linear model (LM). We show how the problem can be characterized as a Generalized Linear Model (GLM) with a Bernoulli distribution. We demonstrate via simulation that this approach is more accurate in estimating the underlying template in the absence of internal noise. With increasing internal noise, however, the advantage of the GLM over the LM decreases and GLM is no more accurate than LM. We then introduce the Generalized Additive Model (GAM), an extension of GLM that can be used to estimate smooth classification images adaptively. We show that this approach is more robust to the presence of internal noise, and finally, we demonstrate that GAM is readily adapted to estimation of higher order (nonlinear) classification images and to testing their significance.

  5. Nonlinear Adjustment Model with Integral and Its Application to Super Resolution Image Reconstruction

    Directory of Open Access Journals (Sweden)

    ZHU Jianjun

    2015-07-01

    Full Text Available The process of super resolution image reconstruction is such a process that multiple observations are taken on the same target to obtain low resolution images, then the low resolution images are used to reconstruct the real image of the target, namely high resolution image. This process is similar to that in the field of surveying and mapping, in which the same target is observed repeatedly and the optimal values is calculated with surveying adjustment methods. In this paper, the method of surveying adjustment is applied into super resolution image reconstruction. A integral nonlinear adjustment model for super resolution image reconstruction is proposed at first. And then the model is parameterized with a quadratic function. Finally the model is solved with the least squares adjustment method. Based on the proposed adjustment method, the specific strategy of image reconstruction is presented. This method for super resolution image reconstruction can make quantitative analysis of the results, and avoid successfully ill-condition problem, etc. The results show that, compared to the traditional method of super resolution image reconstruction, this method has greatly improved the visual effects, and the PSNR and SSIM has also greatly improved, so the method is reliable and feasible.

  6. The additive hazards model with high-dimensional regressors

    DEFF Research Database (Denmark)

    Martinussen, Torben; Scheike, Thomas

    2009-01-01

    This paper considers estimation and prediction in the Aalen additive hazards model in the case where the covariate vector is high-dimensional such as gene expression measurements. Some form of dimension reduction of the covariate space is needed to obtain useful statistical analyses. We study...... model. A standard PLS algorithm can also be constructed, but it turns out that the resulting predictor can only be related to the original covariates via time-dependent coefficients. The methods are applied to a breast cancer data set with gene expression recordings and to the well known primary biliary...

  7. Additive Manufacturing of a 316L Steel Matrix Composite Reinforced with CeO2 Particles: Process Optimization by Adjusting the Laser Scanning Speed

    Directory of Open Access Journals (Sweden)

    Omar O. Salman

    2018-02-01

    Full Text Available The synthesis of novel materials by additive manufacturing requires the optimization of the processing parameters in order to obtain fully-dense defect-free specimens. This step is particularly important for processing of composite materials, where the addition of a second phase may significantly alter the melting and solidification steps. In this work, a composite consisting of a 316L steel matrix and 5 vol.% CeO2 particles was fabricated by selective laser melting (SLM. The SLM parameters leading to a defect-free 316L matrix are not suitable for the production of 316L/CeO2 composite specimens. However, highly-dense composite samples can be synthesized by carefully adjusting the laser scanning speed, while keeping the other parameters constant. The addition of the CeO2 reinforcement does not alter phase formation, but it affects the microstructure of the composite, which is significantly refined compared with the unreinforced 316L material.

  8. Adjusted adaptive Lasso for covariate model-building in nonlinear mixed-effect pharmacokinetic models.

    Science.gov (United States)

    Haem, Elham; Harling, Kajsa; Ayatollahi, Seyyed Mohammad Taghi; Zare, Najaf; Karlsson, Mats O

    2017-02-01

    One important aim in population pharmacokinetics (PK) and pharmacodynamics is identification and quantification of the relationships between the parameters and covariates. Lasso has been suggested as a technique for simultaneous estimation and covariate selection. In linear regression, it has been shown that Lasso possesses no oracle properties, which means it asymptotically performs as though the true underlying model was given in advance. Adaptive Lasso (ALasso) with appropriate initial weights is claimed to possess oracle properties; however, it can lead to poor predictive performance when there is multicollinearity between covariates. This simulation study implemented a new version of ALasso, called adjusted ALasso (AALasso), to take into account the ratio of the standard error of the maximum likelihood (ML) estimator to the ML coefficient as the initial weight in ALasso to deal with multicollinearity in non-linear mixed-effect models. The performance of AALasso was compared with that of ALasso and Lasso. PK data was simulated in four set-ups from a one-compartment bolus input model. Covariates were created by sampling from a multivariate standard normal distribution with no, low (0.2), moderate (0.5) or high (0.7) correlation. The true covariates influenced only clearance at different magnitudes. AALasso, ALasso and Lasso were compared in terms of mean absolute prediction error and error of the estimated covariate coefficient. The results show that AALasso performed better in small data sets, even in those in which a high correlation existed between covariates. This makes AALasso a promising method for covariate selection in nonlinear mixed-effect models.

  9. Modeling process-structure-property relationships for additive manufacturing

    Science.gov (United States)

    Yan, Wentao; Lin, Stephen; Kafka, Orion L.; Yu, Cheng; Liu, Zeliang; Lian, Yanping; Wolff, Sarah; Cao, Jian; Wagner, Gregory J.; Liu, Wing Kam

    2018-02-01

    This paper presents our latest work on comprehensive modeling of process-structure-property relationships for additive manufacturing (AM) materials, including using data-mining techniques to close the cycle of design-predict-optimize. To illustrate the processstructure relationship, the multi-scale multi-physics process modeling starts from the micro-scale to establish a mechanistic heat source model, to the meso-scale models of individual powder particle evolution, and finally to the macro-scale model to simulate the fabrication process of a complex product. To link structure and properties, a highefficiency mechanistic model, self-consistent clustering analyses, is developed to capture a variety of material response. The model incorporates factors such as voids, phase composition, inclusions, and grain structures, which are the differentiating features of AM metals. Furthermore, we propose data-mining as an effective solution for novel rapid design and optimization, which is motivated by the numerous influencing factors in the AM process. We believe this paper will provide a roadmap to advance AM fundamental understanding and guide the monitoring and advanced diagnostics of AM processing.

  10. Additive manufacturing for consumer-centric business models

    DEFF Research Database (Denmark)

    Bogers, Marcel; Hadar, Ronen; Bilberg, Arne

    2016-01-01

    Digital fabrication—including additive manufacturing (AM), rapid prototyping and 3D printing—has the potential to revolutionize the way in which products are produced and delivered to the customer. Therefore, it challenges companies to reinvent their business model—describing the logic of creating...... and capturing value. In this paper, we explore the implications that AM technologies have for manufacturing systems in the new business models that they enable. In particular, we consider how a consumer goods manufacturer can organize the operations of a more open business model when moving from a manufacturer......-centric to a consumer-centric value logic. A major shift includes a move from centralized to decentralized supply chains, where consumer goods manufacturers can implement a “hybrid” approach with a focus on localization and accessibility or develop a fully personalized model where the consumer effectively takes over...

  11. Testing a social ecological model for relations between political violence and child adjustment in Northern Ireland.

    Science.gov (United States)

    Cummings, E Mark; Merrilees, Christine E; Schermerhorn, Alice C; Goeke-Morey, Marcie C; Shirlow, Peter; Cairns, Ed

    2010-05-01

    Relations between political violence and child adjustment are matters of international concern. Past research demonstrates the significance of community, family, and child psychological processes in child adjustment, supporting study of interrelations between multiple social ecological factors and child adjustment in contexts of political violence. Testing a social ecological model, 300 mothers and their children (M = 12.28 years, SD = 1.77) from Catholic and Protestant working class neighborhoods in Belfast, Northern Ireland, completed measures of community discord, family relations, and children's regulatory processes (i.e., emotional security) and outcomes. Historical political violence in neighborhoods based on objective records (i.e., politically motivated deaths) were related to family members' reports of current sectarian antisocial behavior and nonsectarian antisocial behavior. Interparental conflict and parental monitoring and children's emotional security about both the community and family contributed to explanatory pathways for relations between sectarian antisocial behavior in communities and children's adjustment problems. The discussion evaluates support for social ecological models for relations between political violence and child adjustment and its implications for understanding relations in other parts of the world.

  12. Multiscale and Multiphysics Modeling of Additive Manufacturing of Advanced Materials

    Science.gov (United States)

    Liou, Frank; Newkirk, Joseph; Fan, Zhiqiang; Sparks, Todd; Chen, Xueyang; Fletcher, Kenneth; Zhang, Jingwei; Zhang, Yunlu; Kumar, Kannan Suresh; Karnati, Sreekar

    2015-01-01

    The objective of this proposed project is to research and develop a prediction tool for advanced additive manufacturing (AAM) processes for advanced materials and develop experimental methods to provide fundamental properties and establish validation data. Aircraft structures and engines demand materials that are stronger, useable at much higher temperatures, provide less acoustic transmission, and enable more aeroelastic tailoring than those currently used. Significant improvements in properties can only be achieved by processing the materials under nonequilibrium conditions, such as AAM processes. AAM processes encompass a class of processes that use a focused heat source to create a melt pool on a substrate. Examples include Electron Beam Freeform Fabrication and Direct Metal Deposition. These types of additive processes enable fabrication of parts directly from CAD drawings. To achieve the desired material properties and geometries of the final structure, assessing the impact of process parameters and predicting optimized conditions with numerical modeling as an effective prediction tool is necessary. The targets for the processing are multiple and at different spatial scales, and the physical phenomena associated occur in multiphysics and multiscale. In this project, the research work has been developed to model AAM processes in a multiscale and multiphysics approach. A macroscale model was developed to investigate the residual stresses and distortion in AAM processes. A sequentially coupled, thermomechanical, finite element model was developed and validated experimentally. The results showed the temperature distribution, residual stress, and deformation within the formed deposits and substrates. A mesoscale model was developed to include heat transfer, phase change with mushy zone, incompressible free surface flow, solute redistribution, and surface tension. Because of excessive computing time needed, a parallel computing approach was also tested. In addition

  13. Towards an Integrated Conceptual Model of International Student Adjustment and Adaptation

    Science.gov (United States)

    Schartner, Alina; Young, Tony Johnstone

    2016-01-01

    Despite a burgeoning body of empirical research on "the international student experience", the area remains under-theorized. The literature to date lacks a guiding conceptual model that captures the adjustment and adaptation trajectories of this unique, growing, and important sojourner group. In this paper, we therefore put forward a…

  14. 10 km running performance predicted by a multiple linear regression model with allometrically adjusted variables.

    Science.gov (United States)

    Abad, Cesar C C; Barros, Ronaldo V; Bertuzzi, Romulo; Gagliardi, João F L; Lima-Silva, Adriano E; Lambert, Mike I; Pires, Flavio O

    2016-06-01

    The aim of this study was to verify the power of VO 2max , peak treadmill running velocity (PTV), and running economy (RE), unadjusted or allometrically adjusted, in predicting 10 km running performance. Eighteen male endurance runners performed: 1) an incremental test to exhaustion to determine VO 2max and PTV; 2) a constant submaximal run at 12 km·h -1 on an outdoor track for RE determination; and 3) a 10 km running race. Unadjusted (VO 2max , PTV and RE) and adjusted variables (VO 2max 0.72 , PTV 0.72 and RE 0.60 ) were investigated through independent multiple regression models to predict 10 km running race time. There were no significant correlations between 10 km running time and either the adjusted or unadjusted VO 2max . Significant correlations (p 0.84 and power > 0.88. The allometrically adjusted predictive model was composed of PTV 0.72 and RE 0.60 and explained 83% of the variance in 10 km running time with a standard error of the estimate (SEE) of 1.5 min. The unadjusted model composed of a single PVT accounted for 72% of the variance in 10 km running time (SEE of 1.9 min). Both regression models provided powerful estimates of 10 km running time; however, the unadjusted PTV may provide an uncomplicated estimation.

  15. A Threshold Model of Social Support, Adjustment, and Distress after Breast Cancer Treatment

    Science.gov (United States)

    Mallinckrodt, Brent; Armer, Jane M.; Heppner, P. Paul

    2012-01-01

    This study examined a threshold model that proposes that social support exhibits a curvilinear association with adjustment and distress, such that support in excess of a critical threshold level has decreasing incremental benefits. Women diagnosed with a first occurrence of breast cancer (N = 154) completed survey measures of perceived support…

  16. Testing exclusion restrictions and additive separability in sample selection models

    DEFF Research Database (Denmark)

    Huber, Martin; Mellace, Giovanni

    2014-01-01

    Standard sample selection models with non-randomly censored outcomes assume (i) an exclusion restriction (i.e., a variable affecting selection, but not the outcome) and (ii) additive separability of the errors in the selection process. This paper proposes tests for the joint satisfaction of these......Standard sample selection models with non-randomly censored outcomes assume (i) an exclusion restriction (i.e., a variable affecting selection, but not the outcome) and (ii) additive separability of the errors in the selection process. This paper proposes tests for the joint satisfaction...... of these assumptions by applying the approach of Huber and Mellace (Testing instrument validity for LATE identification based on inequality moment constraints, 2011) (for testing instrument validity under treatment endogeneity) to the sample selection framework. We show that the exclusion restriction and additive...... separability imply two testable inequality constraints that come from both point identifying and bounding the outcome distribution of the subpopulation that is always selected/observed. We apply the tests to two variables for which the exclusion restriction is frequently invoked in female wage regressions: non...

  17. Process Modeling and Validation for Metal Big Area Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, Srdjan [ORNL; Nycz, Andrzej [ORNL; Noakes, Mark W. [ORNL; Chin, Charlie [Dassault Systemes; Oancea, Victor [Dassault Systemes

    2017-05-01

    Metal Big Area Additive Manufacturing (mBAAM) is a new additive manufacturing (AM) technology based on the metal arc welding. A continuously fed metal wire is melted by an electric arc that forms between the wire and the substrate, and deposited in the form of a bead of molten metal along the predetermined path. Objects are manufactured one layer at a time starting from the base plate. The final properties of the manufactured object are dependent on its geometry and the metal deposition path, in addition to depending on the basic welding process parameters. Computational modeling can be used to accelerate the development of the mBAAM technology as well as a design and optimization tool for the actual manufacturing process. We have developed a finite element method simulation framework for mBAAM using the new features of software ABAQUS. The computational simulation of material deposition with heat transfer is performed first, followed by the structural analysis based on the temperature history for predicting the final deformation and stress state. In this formulation, we assume that two physics phenomena are coupled in only one direction, i.e. the temperatures are driving the deformation and internal stresses, but their feedback on the temperatures is negligible. The experiment instrumentation (measurement types, sensor types, sensor locations, sensor placements, measurement intervals) and the measurements are presented. The temperatures and distortions from the simulations show good correlation with experimental measurements. Ongoing modeling work is also briefly discussed.

  18. Rational Multi-curve Models with Counterparty-risk Valuation Adjustments

    DEFF Research Database (Denmark)

    Crépey, Stéphane; Macrina, Andrea; Nguyen, Tuyet Mai

    2016-01-01

    We develop a multi-curve term structure set-up in which the modelling ingredients are expressed by rational functionals of Markov processes. We calibrate to London Interbank Offer Rate swaptions data and show that a rational two-factor log-normal multi-curve model is sufficient to match market da...... with regulatory obligations. In order to compute counterparty-risk valuation adjustments, such as credit valuation adjustment, we show how default intensity processes with rational form can be derived. We flesh out our study by applying the results to a basis swap contract....... with accuracy. We elucidate the relationship between the models developed and calibrated under a risk-neutral measure Q and their consistent equivalence class under the real-world probability measure P. The consistent P-pricing models are applied to compute the risk exposures which may be required to comply...

  19. Sensitivity analysis of geometric errors in additive manufacturing medical models.

    Science.gov (United States)

    Pinto, Jose Miguel; Arrieta, Cristobal; Andia, Marcelo E; Uribe, Sergio; Ramos-Grez, Jorge; Vargas, Alex; Irarrazaval, Pablo; Tejos, Cristian

    2015-03-01

    Additive manufacturing (AM) models are used in medical applications for surgical planning, prosthesis design and teaching. For these applications, the accuracy of the AM models is essential. Unfortunately, this accuracy is compromised due to errors introduced by each of the building steps: image acquisition, segmentation, triangulation, printing and infiltration. However, the contribution of each step to the final error remains unclear. We performed a sensitivity analysis comparing errors obtained from a reference with those obtained modifying parameters of each building step. Our analysis considered global indexes to evaluate the overall error, and local indexes to show how this error is distributed along the surface of the AM models. Our results show that the standard building process tends to overestimate the AM models, i.e. models are larger than the original structures. They also show that the triangulation resolution and the segmentation threshold are critical factors, and that the errors are concentrated at regions with high curvatures. Errors could be reduced choosing better triangulation and printing resolutions, but there is an important need for modifying some of the standard building processes, particularly the segmentation algorithms. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. A multistate additive relative survival semi-Markov model.

    Science.gov (United States)

    Gillaizeau, Florence; Dantan, Etienne; Giral, Magali; Foucher, Yohann

    2017-08-01

    Medical researchers are often interested to investigate the relationship between explicative variables and times-to-events such as disease progression or death. Such multiple times-to-events can be studied using multistate models. For chronic diseases, it may be relevant to consider semi-Markov multistate models because the transition intensities between two clinical states more likely depend on the time already spent in the current state than on the chronological time. When the cause of death for a patient is unavailable or not totally attributable to the disease, it is not possible to specifically study the associations with the excess mortality related to the disease. Relative survival analysis allows an estimate of the net survival in the hypothetical situation where the disease would be the only possible cause of death. In this paper, we propose a semi-Markov additive relative survival (SMRS) model that combines the multistate and the relative survival approaches. The usefulness of the SMRS model is illustrated by two applications with data from a French cohort of kidney transplant recipients. Using simulated data, we also highlight the effectiveness of the SMRS model: the results tend to those obtained if the different causes of death are known.

  1. Estimation of oil toxicity using an additive toxicity model

    International Nuclear Information System (INIS)

    French, D.

    2000-01-01

    The impacts to aquatic organisms resulting from acute exposure to aromatic mixtures released from oil spills can be modeled using a newly developed toxicity model. This paper presented a summary of the model development for the toxicity of monoaromatic and polycyclic aromatic hydrocarbon mixtures. This is normally difficult to quantify because oils are mixtures of a variety of hydrocarbons with different toxicities and environmental fates. Also, aromatic hydrocarbons are volatile, making it difficult to expose organism to constant concentrations in bioassay tests. This newly developed and validated model corrects toxicity for time and temperature of exposure. In addition, it estimates the toxicity of each aromatic in the oil-derived mixture. The toxicity of the mixture can be estimated by the weighted sum of the toxicities of the individual compounds. Acute toxicity is estimated as LC50 (lethal concentration to 50 per cent of exposed organisms). Sublethal effects levels are estimated from LC50s. The model was verified with available oil bioassay data. It was concluded that oil toxicity is a function of the aromatic content and composition in the oil as well as the fate and partitioning of those components in the environment. 81 refs., 19 tabs., 1 fig

  2. Implied Adjusted Volatility by Leland Option Pricing Models: Evidence from Australian Index Options

    OpenAIRE

    Mimi Hafizah Abdullah; Hanani Farhah Harun; Nik Ruzni Nik Idris

    2014-01-01

    With the implied volatility as an important factor in financial decision-making, in particular in option pricing valuation, and also the given fact that the pricing biases of Leland option pricing models and the implied volatility structure for the options are related, this study considers examining the implied adjusted volatility smile patterns and term structures in the S&P/ASX 200 index options using the different Leland option pricing models. The examination of the im...

  3. Estimation and variable selection for generalized additive partial linear models

    KAUST Repository

    Wang, Li

    2011-08-01

    We study generalized additive partial linear models, proposing the use of polynomial spline smoothing for estimation of nonparametric functions, and deriving quasi-likelihood based estimators for the linear parameters. We establish asymptotic normality for the estimators of the parametric components. The procedure avoids solving large systems of equations as in kernel-based procedures and thus results in gains in computational simplicity. We further develop a class of variable selection procedures for the linear parameters by employing a nonconcave penalized quasi-likelihood, which is shown to have an asymptotic oracle property. Monte Carlo simulations and an empirical example are presented for illustration. © Institute of Mathematical Statistics, 2011.

  4. Addition Table of Colours: Additive and Subtractive Mixtures Described Using a Single Reasoning Model

    Science.gov (United States)

    Mota, A. R.; Lopes dos Santos, J. M. B.

    2014-01-01

    Students' misconceptions concerning colour phenomena and the apparent complexity of the underlying concepts--due to the different domains of knowledge involved--make its teaching very difficult. We have developed and tested a teaching device, the addition table of colours (ATC), that encompasses additive and subtractive mixtures in a single…

  5. Thermal modelling of extrusion based additive manufacturing of composite materials

    DEFF Research Database (Denmark)

    Jensen, Mathias Laustsen; Sonne, Mads Rostgaard; Hattel, Jesper Henri

    One of the hottest topics regarding manufacturing these years is additive manufacturing (AM). AM is a young branch of manufacturing techniques, which by nature is disruptive due to its completely different manufacturing approach, wherein material is added instead of removed. By adding material...... of composite parts not feasible by conventional manufacturing techniques. This sets up new requirements to the part verification and validation, while conventional destructive tests become too expensive. This initial study aims to investigate alternative options to this destructive testing by increasing......-butadiene-styrene (ABS) and thermosetting polyurethane (PU) material extrusion processes. During the experimental evaluation of the produced models it is found that some critical material properties needs to be further investigated to increase the precision of the model. It is however also found that even with only...

  6. A risk adjusted cost-effectiveness analysis of alternative models of nurse involvement in obesity management in primary care.

    Science.gov (United States)

    Karnon, J; Ali Afzali, H Haji; Gray, J; Holton, C; Banham, D; Beilby, J

    2013-03-01

    Controlled evaluations are subject to uncertainty regarding their replication in the real world, particularly around systems of service provision. Using routinely collected data, we undertook a risk adjusted cost-effectiveness (RAC-E) analysis of alternative applied models of primary health care for the management of obese adult patients. Models were based on the reported level of involvement of practice nurses (registered or enrolled nurses working in general practice) in the provision of clinical-based activities. Linked, routinely collected clinical data describing clinical outcomes (weight, BMI, and obesity-related complications) and resource use (primary care, pharmaceutical, and hospital resource use) were collected. Potential confounders were controlled for using propensity weighted regression analyses. Relative to low level involvement of practice nurses in the provision of clinical-based activities to obese patients, high level involvement was associated with lower costs and better outcomes (more patients losing weight, and larger mean reductions in BMI). Excluding hospital costs, high level practice nurse involvement was associated with slightly higher costs. Incrementally, the high level model gets one additional obese patient to lose weight at an additional cost of $6,741, and reduces mean BMI by an additional one point at an additional cost of $563 (upper 95% confidence interval $1,547). Converted to quality adjusted life year (QALY) gains, the results provide a strong indication that increased involvement of practice nurses in clinical activities is associated with additional health benefits that are achieved at reasonable additional cost. Dissemination activities and incentives are required to encourage general practices to better integrate practice nurses in the active provision of clinical services. Copyright © 2013 The Obesity Society.

  7. Evolution Scenarios at the Romanian Economy Level, Using the R.M. Solow Adjusted Model

    Directory of Open Access Journals (Sweden)

    Stelian Stancu

    2008-06-01

    Full Text Available Besides the models of M. Keynes, R.F. Harrod, E. Domar, D. Romer, Ramsey-Cass-Koopmans model etc., the R.M. Solow model is part of the category which characterizes the economic growth. The paper proposes the presentation of the R.M. Solow adjusted model with specific simulation characteristics and economic growth scenario. Considering these aspects, there are presented the values obtained at the economy level, behind the simulations, about the ratio Capital on the output volume, Output volume on employee, equal with the current labour efficiency, as well as the Labour efficiency value.

  8. WATEQ3 geochemical model: thermodynamic data for several additional solids

    International Nuclear Information System (INIS)

    Krupka, K.M.; Jenne, E.A.

    1982-09-01

    Geochemical models such as WATEQ3 can be used to model the concentrations of water-soluble pollutants that may result from the disposal of nuclear waste and retorted oil shale. However, for a model to competently deal with these water-soluble pollutants, an adequate thermodynamic data base must be provided that includes elements identified as important in modeling these pollutants. To this end, several minerals and related solid phases were identified that were absent from the thermodynamic data base of WATEQ3. In this study, the thermodynamic data for the identified solids were compiled and selected from several published tabulations of thermodynamic data. For these solids, an accepted Gibbs free energy of formation, ΔG 0 /sub f,298/, was selected for each solid phase based on the recentness of the tabulated data and on considerations of internal consistency with respect to both the published tabulations and the existing data in WATEQ3. For those solids not included in these published tabulations, Gibbs free energies of formation were calculated from published solubility data (e.g., lepidocrocite), or were estimated (e.g., nontronite) using a free-energy summation method described by Mattigod and Sposito (1978). The accepted or estimated free energies were then combined with internally consistent, ancillary thermodynamic data to calculate equilibrium constants for the hydrolysis reactions of these minerals and related solid phases. Including these values in the WATEQ3 data base increased the competency of this geochemical model in applications associated with the disposal of nuclear waste and retorted oil shale. Additional minerals and related solid phases that need to be added to the solubility submodel will be identified as modeling applications continue in these two programs

  9. Metal Big Area Additive Manufacturing: Process Modeling and Validation

    Energy Technology Data Exchange (ETDEWEB)

    Simunovic, Srdjan [ORNL; Nycz, Andrzej [ORNL; Noakes, Mark W [ORNL; Chin, Charlie [Dassault Systemes; Oancea, Victor [Dassault Systemes

    2017-01-01

    Metal Big Area Additive Manufacturing (mBAAM) is a new additive manufacturing (AM) technology for printing large-scale 3D objects. mBAAM is based on the gas metal arc welding process and uses a continuous feed of welding wire to manufacture an object. An electric arc forms between the wire and the substrate, which melts the wire and deposits a bead of molten metal along the predetermined path. In general, the welding process parameters and local conditions determine the shape of the deposited bead. The sequence of the bead deposition and the corresponding thermal history of the manufactured object determine the long range effects, such as thermal-induced distortions and residual stresses. Therefore, the resulting performance or final properties of the manufactured object are dependent on its geometry and the deposition path, in addition to depending on the basic welding process parameters. Physical testing is critical for gaining the necessary knowledge for quality prints, but traversing the process parameter space in order to develop an optimized build strategy for each new design is impractical by pure experimental means. Computational modeling and optimization may accelerate development of a build process strategy and saves time and resources. Because computational modeling provides these opportunities, we have developed a physics-based Finite Element Method (FEM) simulation framework and numerical models to support the mBAAM process s development and design. In this paper, we performed a sequentially coupled heat transfer and stress analysis for predicting the final deformation of a small rectangular structure printed using the mild steel welding wire. Using the new simulation technologies, material was progressively added into the FEM simulation as the arc weld traversed the build path. In the sequentially coupled heat transfer and stress analysis, the heat transfer was performed to calculate the temperature evolution, which was used in a stress analysis to

  10. Evaluation of the DAVROS (Development And Validation of Risk-adjusted Outcomes for Systems of emergency care) risk-adjustment model as a quality indicator for healthcare.

    Science.gov (United States)

    Wilson, Richard; Goodacre, Steve W; Klingbajl, Marcin; Kelly, Anne-Maree; Rainer, Tim; Coats, Tim; Holloway, Vikki; Townend, Will; Crane, Steve

    2014-06-01

    Risk-adjusted mortality rates can be used as a quality indicator if it is assumed that the discrepancy between predicted and actual mortality can be attributed to the quality of healthcare (ie, the model has attributional validity). The Development And Validation of Risk-adjusted Outcomes for Systems of emergency care (DAVROS) model predicts 7-day mortality in emergency medical admissions. We aimed to test this assumption by evaluating the attributional validity of the DAVROS risk-adjustment model. We selected cases that had the greatest discrepancy between observed mortality and predicted probability of mortality from seven hospitals involved in validation of the DAVROS risk-adjustment model. Reviewers at each hospital assessed hospital records to determine whether the discrepancy between predicted and actual mortality could be explained by the healthcare provided. We received 232/280 (83%) completed review forms relating to 179 unexpected deaths and 53 unexpected survivors. The healthcare system was judged to have potentially contributed to 10/179 (8%) of the unexpected deaths and 26/53 (49%) of the unexpected survivors. Failure of the model to appropriately predict risk was judged to be responsible for 135/179 (75%) of the unexpected deaths and 2/53 (4%) of the unexpected survivors. Some 10/53 (19%) of the unexpected survivors died within a few months of the 7-day period of model prediction. We found little evidence that deaths occurring in patients with a low predicted mortality from risk-adjustment could be attributed to the quality of healthcare provided. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Geo-additive modelling of malaria in Burundi

    Directory of Open Access Journals (Sweden)

    Gebhardt Albrecht

    2011-08-01

    Full Text Available Abstract Background Malaria is a major public health issue in Burundi in terms of both morbidity and mortality, with around 2.5 million clinical cases and more than 15,000 deaths each year. It is still the single main cause of mortality in pregnant women and children below five years of age. Because of the severe health and economic burden of malaria, there is still a growing need for methods that will help to understand the influencing factors. Several studies/researches have been done on the subject yielding different results as which factors are most responsible for the increase in malaria transmission. This paper considers the modelling of the dependence of malaria cases on spatial determinants and climatic covariates including rainfall, temperature and humidity in Burundi. Methods The analysis carried out in this work exploits real monthly data collected in the area of Burundi over 12 years (1996-2007. Semi-parametric regression models are used. The spatial analysis is based on a geo-additive model using provinces as the geographic units of study. The spatial effect is split into structured (correlated and unstructured (uncorrelated components. Inference is fully Bayesian and uses Markov chain Monte Carlo techniques. The effects of the continuous covariates are modelled by cubic p-splines with 20 equidistant knots and second order random walk penalty. For the spatially correlated effect, Markov random field prior is chosen. The spatially uncorrelated effects are assumed to be i.i.d. Gaussian. The effects of climatic covariates and the effects of other spatial determinants are estimated simultaneously in a unified regression framework. Results The results obtained from the proposed model suggest that although malaria incidence in a given month is strongly positively associated with the minimum temperature of the previous months, regional patterns of malaria that are related to factors other than climatic variables have been identified

  12. [Critical of the additive model of the randomized controlled trial].

    Science.gov (United States)

    Boussageon, Rémy; Gueyffier, François; Bejan-Angoulvant, Theodora; Felden-Dominiak, Géraldine

    2008-01-01

    Randomized, double-blind, placebo-controlled clinical trials are currently the best way to demonstrate the clinical effectiveness of drugs. Its methodology relies on the method of difference (John Stuart Mill), through which the observed difference between two groups (drug vs placebo) can be attributed to the pharmacological effect of the drug being tested. However, this additive model can be questioned in the event of statistical interactions between the pharmacological and the placebo effects. Evidence in different domains has shown that the placebo effect can influence the effect of the active principle. This article evaluates the methodological, clinical and epistemological consequences of this phenomenon. Topics treated include extrapolating results, accounting for heterogeneous results, demonstrating the existence of several factors in the placebo effect, the necessity to take these factors into account for given symptoms or pathologies, as well as the problem of the "specific" effect.

  13. Modeling the Short-Term Effect of Traffic and Meteorology on Air Pollution in Turin with Generalized Additive Models

    Directory of Open Access Journals (Sweden)

    Pancrazio Bertaccini

    2012-01-01

    Full Text Available Vehicular traffic plays an important role in atmospheric pollution and can be used as one of the key predictors in air-quality forecasting models. The models that can account for the role of traffic are especially valuable in urban areas, where high pollutant concentrations are often observed during particular times of day (rush hour and year (winter. In this paper, we develop a generalized additive models approach to analyze the behavior of concentrations of nitrogen dioxide (NO2, and particulate matter (PM10, collected at the environmental monitoring stations distributed throughout the city of Turin, Italy, from December 2003 to April 2005. We describe nonlinear relationships between predictors and pollutants, that are adjusted for unobserved time-varying confounders. We examine several functional forms for the traffic variable and find that a simple form can often provide adequate modeling power. Our analysis shows that there is a saturation effect of traffic on NO2, while such saturation is less evident in models linking traffic to PM10 behavior, having adjusted for meteorological covariates. Moreover, we consider the proposed models separately by seasons and highlight similarities and differences in the predictors’ partial effects. Finally, we show how forecasting can help in evaluating traffic regulation policies.

  14. A metallic solution model with adjustable parameter for describing ternary thermodynamic properties from its binary constituents

    International Nuclear Information System (INIS)

    Fang Zheng; Qiu Guanzhou

    2007-01-01

    A metallic solution model with adjustable parameter k has been developed to predict thermodynamic properties of ternary systems from those of its constituent three binaries. In the present model, the excess Gibbs free energy for a ternary mixture is expressed as a weighted probability sum of those of binaries and the k value is determined based on an assumption that the ternary interaction generally strengthens the mixing effects for metallic solutions with weak interaction, making the Gibbs free energy of mixing of the ternary system more negative than that before considering the interaction. This point is never considered in the models currently reported, where the only difference in a geometrical definition of molar values of components is considered that do not involve thermodynamic principles but are completely empirical. The current model describes the results of experiments very well, and by adjusting the k value also agrees with those from models used widely in the literature. Three ternary systems, Mg-Cu-Ni, Zn-In-Cd, and Cd-Bi-Pb are recalculated to demonstrate the method of determining k and the precision of the model. The results of the calculations, especially those in Mg-Cu-Ni system, are better than those predicted by the current models in the literature

  15. [Applying temporally-adjusted land use regression models to estimate ambient air pollution exposure during pregnancy].

    Science.gov (United States)

    Zhang, Y J; Xue, F X; Bai, Z P

    2017-03-06

    The impact of maternal air pollution exposure on offspring health has received much attention. Precise and feasible exposure estimation is particularly important for clarifying exposure-response relationships and reducing heterogeneity among studies. Temporally-adjusted land use regression (LUR) models are exposure assessment methods developed in recent years that have the advantage of having high spatial-temporal resolution. Studies on the health effects of outdoor air pollution exposure during pregnancy have been increasingly carried out using this model. In China, research applying LUR models was done mostly at the model construction stage, and findings from related epidemiological studies were rarely reported. In this paper, the sources of heterogeneity and research progress of meta-analysis research on the associations between air pollution and adverse pregnancy outcomes were analyzed. The methods of the characteristics of temporally-adjusted LUR models were introduced. The current epidemiological studies on adverse pregnancy outcomes that applied this model were systematically summarized. Recommendations for the development and application of LUR models in China are presented. This will encourage the implementation of more valid exposure predictions during pregnancy in large-scale epidemiological studies on the health effects of air pollution in China.

  16. Additive mathematical model of materials aeration classification in separators

    Directory of Open Access Journals (Sweden)

    V. Ya. Potapov

    2017-09-01

    Full Text Available The article is devoted to confirmation of a mechanism of aeration classification in drum-shelf friction separators of materials, the components of which are distinguished by a wide range of “sailage” in order to increase the separators efficiency and the quality of finished products in technology of components separation of ore and non-ore materials. Using aerodynamics of bodies of arbitrary shape in a directed air flow, a mathematical model is obtained of aeration classification of particles of material components, depending on their physical properties, unified by an integral criterion of “sailage”, and controlled airflow parameters with separate accounting of influence of particles velocity and flow. Equations are obtained for calculation of geometric parameters of a unit of aeration classification friction drum – shelf separator depending on integral criterion of “sailage” determined by shape, size, density of initial raw material and air viscosity providing for maximum quality of stratification of the feedstock and, as a result, increasing the production efficiency and the quality of the separated material. The efficiency of aeration classification with the use of a controlled air flow is confirmed, as well as sufficient convergence of experimental and calculated data. The additive mathematical model has confirmed the high efficiency of application of aeration classification in drum-type friction separators to improve the quality of stratification with reference to initial raw materials, components of which differ in a wide range of “sailage”.

  17. Economic analysis of coal price. Electricity price adjustment in China based on the CGE model

    International Nuclear Information System (INIS)

    He, Y.X.; Yang, L.Y.; Wang, Y.J.; Wang, J.; Zhang, S.L.

    2010-01-01

    In recent years, coal price has risen rapidly, which has also brought a sharp increase in the expenditures of thermal power plants in China. Meantime, the power production price and power retail price have not been adjusted accordingly and a large number of thermal power plants have incurred losses. The power industry is a key industry in the national economy. As such, a thorough analysis and evaluation of the economic influence of the electricity price should be conducted before electricity price adjustment is carried out. This paper analyses the influence of coal price adjustment on the electric power industry, and the influence of electricity price adjustment on the macroeconomy in China based on computable general equilibrium models. The conclusions are as follows: (1) a coal price increase causes a rise in the cost of the electric power industry, but the influence gradually descends with increase in coal price; and (2) an electricity price increase has an adverse influence on the total output, Gross Domestic Product (GDP), and the Consumer Price Index (CPI). Electricity price increases have a contractionary effect on economic development and, consequently, electricity price policy making must consequently consider all factors to minimize their adverse influence. (author)

  18. Conceptual Model for Simulating the Adjustments of Bankfull Characteristics in the Lower Yellow River, China

    Directory of Open Access Journals (Sweden)

    Yuanjian Wang

    2014-01-01

    Full Text Available We present a conceptual model for simulating the temporal adjustments in the banks of the Lower Yellow River (LYR. Basic conservation equations for mass, friction, and sediment transport capacity and the Exner equation were adopted to simulate the hydrodynamics underlying fluvial processes. The relationship between changing rates in bankfull width and depth, derived from quasiuniversal hydraulic geometries, was used as a closure for the hydrodynamic equations. On inputting the daily flow discharge and sediment load, the conceptual model successfully simulated the 30-year adjustments in the bankfull geometries of typical reaches of the LYR. The square of the correlating coefficient reached 0.74 for Huayuankou Station in the multiple-thread reach and exceeded 0.90 for Lijin Station in the meandering reach. This proposed model allows multiple dependent variables and the input of daily hydrological data for long-term simulations. This links the hydrodynamic and geomorphic processes in a fluvial river and has potential applicability to fluvial rivers undergoing significant adjustments.

  19. Estimation of group means when adjusting for covariates in generalized linear models.

    Science.gov (United States)

    Qu, Yongming; Luo, Junxiang

    2015-01-01

    Generalized linear models are commonly used to analyze categorical data such as binary, count, and ordinal outcomes. Adjusting for important prognostic factors or baseline covariates in generalized linear models may improve the estimation efficiency. The model-based mean for a treatment group produced by most software packages estimates the response at the mean covariate, not the mean response for this treatment group for the studied population. Although this is not an issue for linear models, the model-based group mean estimates in generalized linear models could be seriously biased for the true group means. We propose a new method to estimate the group mean consistently with the corresponding variance estimation. Simulation showed the proposed method produces an unbiased estimator for the group means and provided the correct coverage probability. The proposed method was applied to analyze hypoglycemia data from clinical trials in diabetes. Copyright © 2014 John Wiley & Sons, Ltd.

  20. A finite element model updating technique for adjustment of parameters near boundaries

    Science.gov (United States)

    Gwinn, Allen Fort, Jr.

    Even though there have been many advances in research related to methods of updating finite element models based on measured normal mode vibration characteristics, there is yet to be a widely accepted method that works reliably with a wide range of problems. This dissertation focuses on the specific class of problems having to do with changes in stiffness near the clamped boundary of plate structures. This class of problems is especially important as it relates to the performance of turbine engine blades, where a change in stiffness at the base of the blade can be indicative of structural damage. The method that is presented herein is a new technique for resolving the differences between the physical structure and the finite element model. It is a semi-iterative technique that incorporates a "physical expansion" of the measured eigenvectors along with appropriate scaling of these expanded eigenvectors into an iterative loop that uses the Engel's model modification method to then calculate adjusted stiffness parameters for the finite element model. Three example problems are presented that use eigenvalues and mass normalized eigenvectors that have been calculated from experimentally obtained accelerometer readings. The test articles that were used were all thin plates with one edge fully clamped. They each had a cantilevered length of 8.5 inches and a width of 4 inches. The three plates differed from one another in thickness from 0.100 inches to 0.188 inches. These dimensions were selected in order to approximate a gas turbine engine blade. The semi-iterative modification technique is shown to do an excellent job of calculating the necessary adjustments to the finite element model so that the analytically determined eigenvalues and eigenvectors for the adjusted model match the corresponding values from the experimental data with good agreement. Furthermore, the semi-iterative method is quite robust. For the examples presented here, the method consistently converged

  1. Rational Multi-Curve Models with Counterparty-Risk Valuation Adjustments

    DEFF Research Database (Denmark)

    Crepey, Stephane; Macrina, Andrea; Nguyen, Tuyet Mai

    2016-01-01

    We develop a multi-curve term structure setup in which the modelling ingredients are expressed by rational functionals of Markov processes. We calibrate to LIBOR swaptions data and show that a rational two-factor lognormal multi-curve model is sufficient to match market data with accuracy. We elu...... obligations. In order to compute counterparty-risk valuation adjustments, such as CVA, we show how positive default intensity processes with rational form can be derived. We flesh out our study by applying the results to a basis swap contract....

  2. Low dose radiation risks for women surviving the a-bombs in Japan: generalized additive model.

    Science.gov (United States)

    Dropkin, Greg

    2016-11-24

    Analyses of cancer mortality and incidence in Japanese A-bomb survivors have been used to estimate radiation risks, which are generally higher for women. Relative Risk (RR) is usually modelled as a linear function of dose. Extrapolation from data including high doses predicts small risks at low doses. Generalized Additive Models (GAMs) are flexible methods for modelling non-linear behaviour. GAMs are applied to cancer incidence in female low dose subcohorts, using anonymous public data for the 1958 - 1998 Life Span Study, to test for linearity, explore interactions, adjust for the skewed dose distribution, examine significance below 100 mGy, and estimate risks at 10 mGy. For all solid cancer incidence, RR estimated from 0 - 100 mGy and 0 - 20 mGy subcohorts is significantly raised. The response tapers above 150 mGy. At low doses, RR increases with age-at-exposure and decreases with time-since-exposure, the preferred covariate. Using the empirical cumulative distribution of dose improves model fit, and capacity to detect non-linear responses. RR is elevated over wide ranges of covariate values. Results are stable under simulation, or when removing exceptional data cells, or adjusting neutron RBE. Estimates of Excess RR at 10 mGy using the cumulative dose distribution are 10 - 45 times higher than extrapolations from a linear model fitted to the full cohort. Below 100 mGy, quasipoisson models find significant effects for all solid, squamous, uterus, corpus, and thyroid cancers, and for respiratory cancers when age-at-exposure > 35 yrs. Results for the thyroid are compatible with studies of children treated for tinea capitis, and Chernobyl survivors. Results for the uterus are compatible with studies of UK nuclear workers and the Techa River cohort. Non-linear models find large, significant cancer risks for Japanese women exposed to low dose radiation from the atomic bombings. The risks should be reflected in protection standards.

  3. Characterizing and Addressing the Need for Statistical Adjustment of Global Climate Model Data

    Science.gov (United States)

    White, K. D.; Baker, B.; Mueller, C.; Villarini, G.; Foley, P.; Friedman, D.

    2017-12-01

    As part of its mission to research and measure the effects of the changing climate, the U. S. Army Corps of Engineers (USACE) regularly uses the World Climate Research Programme's Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model dataset. However, these data are generated at a global level and are not fine-tuned for specific watersheds. This often causes CMIP5 output to vary from locally observed patterns in the climate. Several downscaling methods have been developed to increase the resolution of the CMIP5 data and decrease systemic differences to support decision-makers as they evaluate results at the watershed scale. Evaluating preliminary comparisons of observed and projected flow frequency curves over the US revealed a simple framework for water resources decision makers to plan and design water resources management measures under changing conditions using standard tools. Using this framework as a basis, USACE has begun to explore to use of statistical adjustment to alter global climate model data to better match the locally observed patterns while preserving the general structure and behavior of the model data. When paired with careful measurement and hypothesis testing, statistical adjustment can be particularly effective at navigating the compromise between the locally observed patterns and the global climate model structures for decision makers.

  4. Remote Sensing-based Methodologies for Snow Model Adjustments in Operational Streamflow Prediction

    Science.gov (United States)

    Bender, S.; Miller, W. P.; Bernard, B.; Stokes, M.; Oaida, C. M.; Painter, T. H.

    2015-12-01

    Water management agencies rely on hydrologic forecasts issued by operational agencies such as NOAA's Colorado Basin River Forecast Center (CBRFC). The CBRFC has partnered with the Jet Propulsion Laboratory (JPL) under funding from NASA to incorporate research-oriented, remotely-sensed snow data into CBRFC operations and to improve the accuracy of CBRFC forecasts. The partnership has yielded valuable analysis of snow surface albedo as represented in JPL's MODIS Dust Radiative Forcing in Snow (MODDRFS) data, across the CBRFC's area of responsibility. When dust layers within a snowpack emerge, reducing the snow surface albedo, the snowmelt rate may accelerate. The CBRFC operational snow model (SNOW17) is a temperature-index model that lacks explicit representation of snowpack surface albedo. CBRFC forecasters monitor MODDRFS data for emerging dust layers and may manually adjust SNOW17 melt rates. A technique was needed for efficient and objective incorporation of the MODDRFS data into SNOW17. Initial development focused in Colorado, where dust-on-snow events frequently occur. CBRFC forecasters used retrospective JPL-CBRFC analysis and developed a quantitative relationship between MODDRFS data and mean areal temperature (MAT) data. The relationship was used to generate adjusted, MODDRFS-informed input for SNOW17. Impacts of the MODDRFS-SNOW17 MAT adjustment method on snowmelt-driven streamflow prediction varied spatially and with characteristics of the dust deposition events. The largest improvements occurred in southwestern Colorado, in years with intense dust deposition events. Application of the method in other regions of Colorado and in "low dust" years resulted in minimal impact. The MODDRFS-SNOW17 MAT technique will be implemented in CBRFC operations in late 2015, prior to spring 2016 runoff. Collaborative investigation of remote sensing-based adjustment methods for the CBRFC operational hydrologic forecasting environment will continue over the next several years.

  5. Glacial isostatic adjustment using GNSS permanent stations and GIA modelling tools

    Science.gov (United States)

    Kollo, Karin; Spada, Giorgio; Vermeer, Martin

    2013-04-01

    Glacial Isostatic Adjustment (GIA) affects the Earth's mantle in areas which were once ice covered and the process is still ongoing. In this contribution we focus on GIA processes in Fennoscandian and North American uplift regions. In this contribution we use horizontal and vertical uplift rates from Global Navigation Satellite System (GNSS) permanent stations. For Fennoscandia the BIFROST dataset (Lidberg, 2010) and North America the dataset from Sella, 2007 were used respectively. We perform GIA modelling with the SELEN program (Spada and Stocchi, 2007) and we vary ice model parameters in space in order to find ice model which suits best with uplift values obtained from GNSS time series analysis. In the GIA modelling, the ice models ICE-5G (Peltier, 2004) and the ice model denoted as ANU05 ((Fleming and Lambeck, 2004) and references therein) were used. As reference, the velocity field from GNSS permanent station time series was used for both target areas. Firstly the sensitivity to the harmonic degree was tested in order to reduce the computation time. In the test, nominal viscosity values and pre-defined lithosphere thicknesses models were used, varying maximum harmonic degree values. Main criteria for choosing the suitable harmonic degree was chi-square fit - if the error measure does not differ more than 10%, then one might use as well lower harmonic degree value. From this test, maximum harmonic degree of 72 was chosen to perform calculations, as the larger value did not significantly modify the results obtained, as well the computational time for observations was kept reasonable. Secondly the GIA computations were performed to find the model, which could fit with highest probability to the GNSS-based velocity field in the target areas. In order to find best fitting Earth viscosity parameters, different viscosity profiles for the Earth models were tested and their impact on horizontal and vertical velocity rates from GIA modelling was studied. For every

  6. Family support and acceptance, gay male identity formation, and psychological adjustment: a path model.

    Science.gov (United States)

    Elizur, Y; Ziv, M

    2001-01-01

    While heterosexist family undermining has been demonstrated to be a developmental risk factor in the life of persons with same-gender orientation, the issue of protective family factors is both controversial and relatively neglected. In this study of Israeli gay males (N = 114), we focused on the interrelations of family support, family acceptance and family knowledge of gay orientation, and gay male identity formation, and their effects on mental health and self-esteem. A path model was proposed based on the hypotheses that family support, family acceptance, family knowledge, and gay identity formation have an impact on psychological adjustment, and that family support has an effect on gay identity formation that is mediated by family acceptance. The assessment of gay identity formation was based on an established stage model that was streamlined for cross-cultural practice by defining three basic processes of same-gender identity formation: self-definition, self-acceptance, and disclosure (Elizur & Mintzer, 2001). The testing of our conceptual path model demonstrated an excellent fit with the data. An alternative model that hypothesized effects of gay male identity on family acceptance and family knowledge did not fit the data. Interpreting these results, we propose that the main effect of family support/acceptance on gay identity is related to the process of disclosure, and that both general family support and family acceptance of same-gender orientation play a significant role in the psychological adjustment of gay men.

  7. Predictive Model for Environmental Assessment in Additive Manufacturing Process

    OpenAIRE

    Le Bourhis , Florent; Kerbrat , Olivier; Dembinski , Lucas; Hascoët , Jean-Yves; Mognol , Pascal

    2014-01-01

    International audience; Additive Manufacturing is an innovative way to produce parts. However its environmental impact is unknown. To ensure the development of additive manufacturing processes it seems important to develop the concept of DFSAM (Design for Sustainable Additive Manufacturing). In fact, one of the objectives of environmental sustainable manufacturing is to minimize the whole flux consumption (electricity, material and fluids) during manufacturing step. To achieve this goal, it i...

  8. Additional Research Needs to Support the GENII Biosphere Models

    Energy Technology Data Exchange (ETDEWEB)

    Napier, Bruce A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Sandra F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arimescu, Carmen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2013-11-01

    In the course of evaluating the current parameter needs for the GENII Version 2 code (Snyder et al. 2013), areas of possible improvement for both the data and the underlying models have been identified. As the data review was implemented, PNNL staff identified areas where the models can be improved both to accommodate the locally significant pathways identified and also to incorporate newer models. The areas are general data needs for the existing models and improved formulations for the pathway models.

  9. Analisis Portofolio Optimum Saham Syariah Menggunakan Liquidity Adjusted Capital Asset Pricing Model (LCAPM

    Directory of Open Access Journals (Sweden)

    Nila Cahyati

    2015-04-01

    Full Text Available Investasi mempunyai karakteristik antara return dan resiko. Pembentukan portofolio optimal digunakan untuk memaksimalkan keuntungan dan meminimumkan resiko. Liquidity Adjusted Capital Asset Pricing Model (LCAPM merupakan metode pengembangan baru dari CAPM yang dipengaruhi likuiditas. Indikator likuiditas apabila digabungkan dengan metode CAPM dapat membantu memaksimalkan return dan meminimumkan resiko. Tujuan penelitian adalah membandingkan expected retun dan resiko saham serta mengetahui proporsi pada portofolio optimal. Sampel yang digunakan merupakan saham JII (Jakarta Islamic Index  periode Januari 2013 – November 2014. Hasil penelitian menunjukkan bahwa expected return portofolio LCAPM sebesar 0,0956 dengan resiko 0,0043 yang membentuk proporsi saham AALI (55,19% dan saham PGAS (44,81%.

  10. Modeling and Control of Adjustable Articulated Parallel Compliant Actuation Arrangements in Articulated Robots

    Directory of Open Access Journals (Sweden)

    Wesley Roozing

    2018-02-01

    Full Text Available Considerable advances in robotic actuation technology have been made in recent years. Particularly the use of compliance has increased, both as series elastic elements as well as in parallel to the main actuation drives. This work focuses on the model formulation and control of compliant actuation structures including multiple branches and multiarticulation, and significantly contributes by proposing an elegant modular formulation that describes the energy exchange between the compliant elements and articulated multibody robot dynamics using the concept of power flows, and a single matrix that describes the entire actuation topology. Using this formulation, a novel gradient descent based control law is derived for torque control of compliant actuation structures with adjustable pretension, with proven convexity for arbitrary actuation topologies. Extensions toward handling unidirectionality of elastic elements and joint motion compensation are also presented. A simulation study is performed on a 3-DoF leg model, where series-elastic main drives are augmented by parallel elastic tendons with adjustable pretension. Two actuation topologies are considered, one of which includes a biarticulated tendon. The data demonstrate the effectiveness of the proposed modeling and control methods. Furthermore, it is shown the biarticulated topology provides significant benefits over the monoarticulated arrangement.

  11. Obtaining adjusted prevalence ratios from logistic regression models in cross-sectional studies.

    Science.gov (United States)

    Bastos, Leonardo Soares; Oliveira, Raquel de Vasconcellos Carvalhaes de; Velasque, Luciane de Souza

    2015-03-01

    In the last decades, the use of the epidemiological prevalence ratio (PR) instead of the odds ratio has been debated as a measure of association in cross-sectional studies. This article addresses the main difficulties in the use of statistical models for the calculation of PR: convergence problems, availability of tools and inappropriate assumptions. We implement the direct approach to estimate the PR from binary regression models based on two methods proposed by Wilcosky & Chambless and compare with different methods. We used three examples and compared the crude and adjusted estimate of PR, with the estimates obtained by use of log-binomial, Poisson regression and the prevalence odds ratio (POR). PRs obtained from the direct approach resulted in values close enough to those obtained by log-binomial and Poisson, while the POR overestimated the PR. The model implemented here showed the following advantages: no numerical instability; assumes adequate probability distribution and, is available through the R statistical package.

  12. Empiric model for mean generation time adjustment factor for classic point kinetics equations

    International Nuclear Information System (INIS)

    Goes, David A.B.V. de; Martinez, Aquilino S.; Goncalves, Alessandro da C.

    2017-01-01

    Point reactor kinetics equations are the easiest way to observe the neutron production time behavior in a nuclear reactor. These equations are derived from the neutron transport equation using an approximation called Fick's law leading to a set of first order differential equations. The main objective of this study is to review classic point kinetics equation in order to approximate its results to the case when it is considered the time variation of the neutron currents. The computational modeling used for the calculations is based on the finite difference method. The results obtained with this model are compared with the reference model and then it is determined an empirical adjustment factor that modifies the point reactor kinetics equation to the real scenario. (author)

  13. Empiric model for mean generation time adjustment factor for classic point kinetics equations

    Energy Technology Data Exchange (ETDEWEB)

    Goes, David A.B.V. de; Martinez, Aquilino S.; Goncalves, Alessandro da C., E-mail: david.goes@poli.ufrj.br, E-mail: aquilino@lmp.ufrj.br, E-mail: alessandro@con.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Nuclear

    2017-11-01

    Point reactor kinetics equations are the easiest way to observe the neutron production time behavior in a nuclear reactor. These equations are derived from the neutron transport equation using an approximation called Fick's law leading to a set of first order differential equations. The main objective of this study is to review classic point kinetics equation in order to approximate its results to the case when it is considered the time variation of the neutron currents. The computational modeling used for the calculations is based on the finite difference method. The results obtained with this model are compared with the reference model and then it is determined an empirical adjustment factor that modifies the point reactor kinetics equation to the real scenario. (author)

  14. Feasibility and Psychometric Properties of the Adjusted DSWAL-QoL Questionnaire for Dysphagic Patients with Additional Language and/or Cognitive Impairment: Part I.

    Science.gov (United States)

    Simpelaere, Ingeborg S; Vanderwegen, Jan; Wouters, Kristien; De Bodt, Marc; Van Nuffelen, Gwen

    2017-06-01

    The Swallowing Quality-of-Life questionnaire (SWAL-QoL) is considered the gold standard for assessing health-related quality of life in people with dysphagia. However, many dysphagic patients struggle to complete this questionnaire because of additional functional sequelae such as language impairment and cognitive disorders. In this study, we sought to develop an adjusted Dutch version of the SWAL-QoL (aDSWALQoL) and to evaluate its psychometric properties and feasibility compared with the original questionnaire. We developed the aDSWAL-QoL based on recommendations from previous literature. The feasibility, internal consistency, test-retest reliability, and criterion validity of the aDSWAL-QoL were evaluated in 78 dysphagic patients, among whom 43 had additional language and/or cognitive impairments (DysLC). Statistical analyses were performed using SPSS 20.0. The aDSWAL-QoL had a higher degree of feasibility for the DysLC group. We obtained high Cronbach's α coefficients for total scale and for almost all subscales. Total aDSWAL-QoL scores showed excellent testretest agreement and good criterion validity with respect to the DSWAL-QoL. Almost all subscales showed significantly moderate to good test-retest agreement and criterion validity. However, the psychometric properties of the 'Food selection' subscale were inadequate. The aDSWAL-QoL is a feasible, reliable, and valid tool for use with DysLC patients. Conversion of the aDSWAL-QoL into an audio computer-assisted self-administered format should be investigated. The construct validity of the aDSWAL-QoL will be evaluated in a separate report.

  15. Uncertainties in Tidally Adjusted Estimates of Sea Level Rise Flooding (Bathtub Model for the Greater London

    Directory of Open Access Journals (Sweden)

    Ali P. Yunus

    2016-04-01

    Full Text Available Sea-level rise (SLR from global warming may have severe consequences for coastal cities, particularly when combined with predicted increases in the strength of tidal surges. Predicting the regional impact of SLR flooding is strongly dependent on the modelling approach and accuracy of topographic data. Here, the areas under risk of sea water flooding for London boroughs were quantified based on the projected SLR scenarios reported in Intergovernmental Panel on Climate Change (IPCC fifth assessment report (AR5 and UK climatic projections 2009 (UKCP09 using a tidally-adjusted bathtub modelling approach. Medium- to very high-resolution digital elevation models (DEMs are used to evaluate inundation extents as well as uncertainties. Depending on the SLR scenario and DEMs used, it is estimated that 3%–8% of the area of Greater London could be inundated by 2100. The boroughs with the largest areas at risk of flooding are Newham, Southwark, and Greenwich. The differences in inundation areas estimated from a digital terrain model and a digital surface model are much greater than the root mean square error differences observed between the two data types, which may be attributed to processing levels. Flood models from SRTM data underestimate the inundation extent, so their results may not be reliable for constructing flood risk maps. This analysis provides a broad-scale estimate of the potential consequences of SLR and uncertainties in the DEM-based bathtub type flood inundation modelling for London boroughs.

  16. Additive Manufacturing of Anatomical Models from Computed Tomography Scan Data.

    Science.gov (United States)

    Gür, Y

    2014-12-01

    The purpose of the study presented here was to investigate the manufacturability of human anatomical models from Computed Tomography (CT) scan data via a 3D desktop printer which uses fused deposition modelling (FDM) technology. First, Digital Imaging and Communications in Medicine (DICOM) CT scan data were converted to 3D Standard Triangle Language (STL) format by using In Vaselius digital imaging program. Once this STL file is obtained, a 3D physical version of the anatomical model can be fabricated by a desktop 3D FDM printer. As a case study, a patient's skull CT scan data was considered, and a tangible version of the skull was manufactured by a 3D FDM desktop printer. During the 3D printing process, the skull was built using acrylonitrile-butadiene-styrene (ABS) co-polymer plastic. The printed model showed that the 3D FDM printing technology is able to fabricate anatomical models with high accuracy. As a result, the skull model can be used for preoperative surgical planning, medical training activities, implant design and simulation to show the potential of the FDM technology in medical field. It will also improve communication between medical stuff and patients. Current result indicates that a 3D desktop printer which uses FDM technology can be used to obtain accurate anatomical models.

  17. The Trauma Outcome Process Assessment Model: A Structural Equation Model Examination of Adjustment

    Science.gov (United States)

    Borja, Susan E.; Callahan, Jennifer L.

    2009-01-01

    This investigation sought to operationalize a comprehensive theoretical model, the Trauma Outcome Process Assessment, and test it empirically with structural equation modeling. The Trauma Outcome Process Assessment reflects a robust body of research and incorporates known ecological factors (e.g., family dynamics, social support) to explain…

  18. Multiple Imputation of Predictor Variables Using Generalized Additive Models

    NARCIS (Netherlands)

    de Jong, Roel; van Buuren, Stef; Spiess, Martin

    2016-01-01

    The sensitivity of multiple imputation methods to deviations from their distributional assumptions is investigated using simulations, where the parameters of scientific interest are the coefficients of a linear regression model, and values in predictor variables are missing at random. The

  19. Primary circuit iodine model addition to IMPAIR-3

    Energy Technology Data Exchange (ETDEWEB)

    Osetek, D.J.; Louie, D.L.Y. [Los Alamos Technical Associates, Inc., Albuquerque, NM (United States); Guntay, S.; Cripps, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-12-01

    As part of a continuing effort to provide the U.S. Department of Energy (DOE) Advanced Reactor Severe Accident Program (ARSAP) with complete iodine analysis capability, a task was undertaken to expand the modeling of IMPAIR-3, an iodine chemistry code. The expanded code will enable the DOE to include detailed iodine behavior in the assessment of severe accident source terms used in the licensing of U.S. Advanced Light Water Reactors (ALWRs). IMPAIR-3 was developed at the Paul Scherrer Institute (PSI), Switzerland, and has been used by ARSAP for the past two years to analyze containment iodine chemistry for ALWR source term analyses. IMPAIR-3 is primarily a containment code but the iodine chemistry inside the primary circuit (the Reactor Coolant System or RCS) may influence the iodine species released into the the containment; therefore, a RCS iodine chemistry model must be implemented in IMPAIR-3 to ensure thorough source term analysis. The ARSAP source term team and the PSI IMPAIR-3 developers are working together to accomplish this task. This cooperation is divided into two phases. Phase I, taking place in 1996, involves developing a stand-alone RCS iodine chemistry program called IMPRCS (IMPAIR -Reactor Coolant System). This program models a number of the chemical and physical processes of iodine that are thought to be important at conditions of high temperature and pressure in the RCS. In Phase II, which is tentatively scheduled for 1997, IMPRCS will be implemented as a subroutine in IMPAIR-3. To ensure an efficient calculation, an interface/tracking system will be developed to control the use of the RCS model from the containment model. These two models will be interfaced in such a way that once the iodine is released from the RCS, it will no longer be tracked by the RCS model but will be tracked by the containment model. All RCS thermal-hydraulic parameters will be provided by other codes. (author) figs., tabs., refs.

  20. Primary circuit iodine model addition to IMPAIR-3

    International Nuclear Information System (INIS)

    Osetek, D.J.; Louie, D.L.Y.; Guntay, S.; Cripps, R.

    1996-01-01

    As part of a continuing effort to provide the U.S. Department of Energy (DOE) Advanced Reactor Severe Accident Program (ARSAP) with complete iodine analysis capability, a task was undertaken to expand the modeling of IMPAIR-3, an iodine chemistry code. The expanded code will enable the DOE to include detailed iodine behavior in the assessment of severe accident source terms used in the licensing of U.S. Advanced Light Water Reactors (ALWRs). IMPAIR-3 was developed at the Paul Scherrer Institute (PSI), Switzerland, and has been used by ARSAP for the past two years to analyze containment iodine chemistry for ALWR source term analyses. IMPAIR-3 is primarily a containment code but the iodine chemistry inside the primary circuit (the Reactor Coolant System or RCS) may influence the iodine species released into the the containment; therefore, a RCS iodine chemistry model must be implemented in IMPAIR-3 to ensure thorough source term analysis. The ARSAP source term team and the PSI IMPAIR-3 developers are working together to accomplish this task. This cooperation is divided into two phases. Phase I, taking place in 1996, involves developing a stand-alone RCS iodine chemistry program called IMPRCS (IMPAIR -Reactor Coolant System). This program models a number of the chemical and physical processes of iodine that are thought to be important at conditions of high temperature and pressure in the RCS. In Phase II, which is tentatively scheduled for 1997, IMPRCS will be implemented as a subroutine in IMPAIR-3. To ensure an efficient calculation, an interface/tracking system will be developed to control the use of the RCS model from the containment model. These two models will be interfaced in such a way that once the iodine is released from the RCS, it will no longer be tracked by the RCS model but will be tracked by the containment model. All RCS thermal-hydraulic parameters will be provided by other codes. (author) figs., tabs., refs

  1. Modeling of multivariate longitudinal phenotypes in family genetic studies with Bayesian multiplicity adjustment

    OpenAIRE

    Ding, Lili; Kurowski, Brad G; He, Hua; Alexander, Eileen S; Mersha, Tesfaye B; Fardo, David W; Zhang, Xue; Pilipenko, Valentina V; Kottyan, Leah; Martin, Lisa J

    2014-01-01

    Genetic studies often collect data on multiple traits. Most genetic association analyses, however, consider traits separately and ignore potential correlation among traits, partially because of difficulties in statistical modeling of multivariate outcomes. When multiple traits are measured in a pedigree longitudinally, additional challenges arise because in addition to correlation between traits, a trait is often correlated with its own measures over time and with measurements of other family...

  2. Measurement of the Economic Growth and Add-on of the R.M. Solow Adjusted Model

    Directory of Open Access Journals (Sweden)

    Ion Gh. Rosca

    2007-08-01

    Full Text Available Besides the models of M. Keynes, R.F. Harrod, E. Domar, D. Romer, Ramsey-Cass-Koopmans model etc., the R.M. Solow model is part of the category which characterizes the economic growth.The paper aim is the economic growth measurement and add-on of the R.M. Solow adjusted model.

  3. Adjusting Satellite Rainfall Error in Mountainous Areas for Flood Modeling Applications

    Science.gov (United States)

    Zhang, X.; Anagnostou, E. N.; Astitha, M.; Vergara, H. J.; Gourley, J. J.; Hong, Y.

    2014-12-01

    This study aims to investigate the use of high-resolution Numerical Weather Prediction (NWP) for evaluating biases of satellite rainfall estimates of flood-inducing storms in mountainous areas and associated improvements in flood modeling. Satellite-retrieved precipitation has been considered as a feasible data source for global-scale flood modeling, given that satellite has the spatial coverage advantage over in situ (rain gauges and radar) observations particularly over mountainous areas. However, orographically induced heavy precipitation events tend to be underestimated and spatially smoothed by satellite products, which error propagates non-linearly in flood simulations.We apply a recently developed retrieval error and resolution effect correction method (Zhang et al. 2013*) on the NOAA Climate Prediction Center morphing technique (CMORPH) product based on NWP analysis (or forecasting in the case of real-time satellite products). The NWP rainfall is derived from the Weather Research and Forecasting Model (WRF) set up with high spatial resolution (1-2 km) and explicit treatment of precipitation microphysics.In this study we will show results on NWP-adjusted CMORPH rain rates based on tropical cyclones and a convective precipitation event measured during NASA's IPHEX experiment in the South Appalachian region. We will use hydrologic simulations over different basins in the region to evaluate propagation of bias correction in flood simulations. We show that the adjustment reduced the underestimation of high rain rates thus moderating the strong rainfall magnitude dependence of CMORPH rainfall bias, which results in significant improvement in flood peak simulations. Further study over Blue Nile Basin (western Ethiopia) will be investigated and included in the presentation. *Zhang, X. et al. 2013: Using NWP Simulations in Satellite Rainfall Estimation of Heavy Precipitation Events over Mountainous Areas. J. Hydrometeor, 14, 1844-1858.

  4. Adjusting Felder-Silverman learning styles model for application in adaptive e-learning

    Directory of Open Access Journals (Sweden)

    Mihailović Đorđe

    2012-01-01

    Full Text Available This paper presents an approach for adjusting Felder-Silverman learning styles model for application in development of adaptive e-learning systems. Main goal of the paper is to improve the existing e-learning courses by developing a method for adaptation based on learning styles. The proposed method includes analysis of data related to students characteristics and applying the concept of personalization in creating e-learning courses. The research has been conducted at Faculty of organizational sciences, University of Belgrade, during winter semester of 2009/10, on sample of 318 students. The students from the experimental group were divided in three clusters, based on data about their styles identified using adjusted Felder-Silverman questionnaire. Data about learning styles collected during the research were used to determine typical groups of students and then to classify students into these groups. The classification was performed using data mining techniques. Adaptation of the e-learning courses was implemented according to results of data analysis. Evaluation showed that there was statistically significant difference in the results of students who attended the course adapted by using the described method, in comparison with results of students who attended course that was not adapted.

  5. Risk-adjusted performance evaluation in three academic thoracic surgery units using the Eurolung risk models.

    Science.gov (United States)

    Pompili, Cecilia; Shargall, Yaron; Decaluwe, Herbert; Moons, Johnny; Chari, Madhu; Brunelli, Alessandro

    2018-01-03

    The objective of this study was to evaluate the performance of 3 thoracic surgery centres using the Eurolung risk models for morbidity and mortality. This was a retrospective analysis performed on data collected from 3 academic centres (2014-2016). Seven hundred and twenty-one patients in Centre 1, 857 patients in Centre 2 and 433 patients in Centre 3 who underwent anatomical lung resections were analysed. The Eurolung1 and Eurolung2 models were used to predict risk-adjusted cardiopulmonary morbidity and 30-day mortality rates. Observed and risk-adjusted outcomes were compared within each centre. The observed morbidity of Centre 1 was in line with the predicted morbidity (observed 21.1% vs predicted 22.7%, P = 0.31). Centre 2 performed better than expected (observed morbidity 20.2% vs predicted 26.7%, P < 0.001), whereas the observed morbidity of Centre 3 was higher than the predicted morbidity (observed 41.1% vs predicted 24.3%, P < 0.001). Centre 1 had higher observed mortality when compared with the predicted mortality (3.6% vs 2.1%, P = 0.005), whereas Centre 2 had an observed mortality rate significantly lower than the predicted mortality rate (1.2% vs 2.5%, P = 0.013). Centre 3 had an observed mortality rate in line with the predicted mortality rate (observed 1.4% vs predicted 2.4%, P = 0.17). The observed mortality rates in the patients with major complications were 30.8% in Centre 1 (versus predicted mortality rate 3.8%, P < 0.001), 8.2% in Centre 2 (versus predicted mortality rate 4.1%, P = 0.030) and 9.0% in Centre 3 (versus predicted mortality rate 3.5%, P = 0.014). The Eurolung models were successfully used as risk-adjusting instruments to internally audit the outcomes of 3 different centres, showing their applicability for future quality improvement initiatives. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  6. Analysis of time to event outcomes in randomized controlled trials by generalized additive models.

    Directory of Open Access Journals (Sweden)

    Christos Argyropoulos

    Full Text Available Randomized Controlled Trials almost invariably utilize the hazard ratio calculated with a Cox proportional hazard model as a treatment efficacy measure. Despite the widespread adoption of HRs, these provide a limited understanding of the treatment effect and may even provide a biased estimate when the assumption of proportional hazards in the Cox model is not verified by the trial data. Additional treatment effect measures on the survival probability or the time scale may be used to supplement HRs but a framework for the simultaneous generation of these measures is lacking.By splitting follow-up time at the nodes of a Gauss Lobatto numerical quadrature rule, techniques for Poisson Generalized Additive Models (PGAM can be adopted for flexible hazard modeling. Straightforward simulation post-estimation transforms PGAM estimates for the log hazard into estimates of the survival function. These in turn were used to calculate relative and absolute risks or even differences in restricted mean survival time between treatment arms. We illustrate our approach with extensive simulations and in two trials: IPASS (in which the proportionality of hazards was violated and HEMO a long duration study conducted under evolving standards of care on a heterogeneous patient population.PGAM can generate estimates of the survival function and the hazard ratio that are essentially identical to those obtained by Kaplan Meier curve analysis and the Cox model. PGAMs can simultaneously provide multiple measures of treatment efficacy after a single data pass. Furthermore, supported unadjusted (overall treatment effect but also subgroup and adjusted analyses, while incorporating multiple time scales and accounting for non-proportional hazards in survival data.By augmenting the HR conventionally reported, PGAMs have the potential to support the inferential goals of multiple stakeholders involved in the evaluation and appraisal of clinical trial results under proportional and

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

    Science.gov (United States)

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

    2016-01-01

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

  8. Modeling additive and non-additive effects in a hybrid population using genome-wide genotyping: prediction accuracy implications.

    Science.gov (United States)

    Bouvet, J-M; Makouanzi, G; Cros, D; Vigneron, Ph

    2016-02-01

    Hybrids are broadly used in plant breeding and accurate estimation of variance components is crucial for optimizing genetic gain. Genome-wide information may be used to explore models designed to assess the extent of additive and non-additive variance and test their prediction accuracy for the genomic selection. Ten linear mixed models, involving pedigree- and marker-based relationship matrices among parents, were developed to estimate additive (A), dominance (D) and epistatic (AA, AD and DD) effects. Five complementary models, involving the gametic phase to estimate marker-based relationships among hybrid progenies, were developed to assess the same effects. The models were compared using tree height and 3303 single-nucleotide polymorphism markers from 1130 cloned individuals obtained via controlled crosses of 13 Eucalyptus urophylla females with 9 Eucalyptus grandis males. Akaike information criterion (AIC), variance ratios, asymptotic correlation matrices of estimates, goodness-of-fit, prediction accuracy and mean square error (MSE) were used for the comparisons. The variance components and variance ratios differed according to the model. Models with a parent marker-based relationship matrix performed better than those that were pedigree-based, that is, an absence of singularities, lower AIC, higher goodness-of-fit and accuracy and smaller MSE. However, AD and DD variances were estimated with high s.es. Using the same criteria, progeny gametic phase-based models performed better in fitting the observations and predicting genetic values. However, DD variance could not be separated from the dominance variance and null estimates were obtained for AA and AD effects. This study highlighted the advantages of progeny models using genome-wide information.

  9. A Proportional Hazards Regression Model for the Subdistribution with Covariates-adjusted Censoring Weight for Competing Risks Data

    DEFF Research Database (Denmark)

    He, Peng; Eriksson, Frank; Scheike, Thomas H.

    2016-01-01

    and the covariates are independent. Covariate-dependent censoring sometimes occurs in medical studies. In this paper, we study the proportional hazards regression model for the subdistribution of a competing risk with proper adjustments for covariate-dependent censoring. We consider a covariate-adjusted weight......With competing risks data, one often needs to assess the treatment and covariate effects on the cumulative incidence function. Fine and Gray proposed a proportional hazards regression model for the subdistribution of a competing risk with the assumption that the censoring distribution...... function by fitting the Cox model for the censoring distribution and using the predictive probability for each individual. Our simulation study shows that the covariate-adjusted weight estimator is basically unbiased when the censoring time depends on the covariates, and the covariate-adjusted weight...

  10. A risk-adjusted economic evaluation of alternative models of involvement of practice nurses in management of type 2 diabetes.

    Science.gov (United States)

    Haji Ali Afzali, H; Gray, J; Beilby, J; Holton, C; Banham, D; Karnon, J

    2013-07-01

    To determine the cost-effectiveness of alternative models of practice nurse involvement in the management of type 2 diabetes within the primary care setting. Linked routinely collected clinical data and resource use (general practitioner visits, hospital services and pharmaceuticals) were used to undertake a risk-adjusted cost-effectiveness analysis of alternative models of care for the management of diabetes patients. These models were based on the reported level of involvement of practice nurses in the provision of clinical-based activities. Potential confounders were controlled for by using propensity score-weighted regression analyses. The impact of alternative models of care on outcomes and costs was measured and incremental cost-effectiveness estimated. The uncertainty around the estimates of cost-effectiveness was illustrated through bootstrapping. Although the difference in total cost between two models of care was not statistically significant, the high-level model was associated with better outcomes (larger mean reductions in HbA(1c)). The upper 95% confidence intervals showed that the incremental cost per 1% decrease in HbA(1c) is only $454, and per one additional patient to achieve an HbA(1c) value of less than 53 mmol/mol (7.0%) is $323. Further analyses showed little uncertainty surrounding the decision to adopt the high-level model. The results provide a strong indication that the high-level model is a cost-effective way of managing diabetes patients. Our findings highlight the need for effective incentives to encourage general practices to better integrate practice nurses in the provision of clinical services. © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.

  11. Short term load forecasting technique based on the seasonal exponential adjustment method and the regression model

    International Nuclear Information System (INIS)

    Wu, Jie; Wang, Jianzhou; Lu, Haiyan; Dong, Yao; Lu, Xiaoxiao

    2013-01-01

    Highlights: ► The seasonal and trend items of the data series are forecasted separately. ► Seasonal item in the data series is verified by the Kendall τ correlation testing. ► Different regression models are applied to the trend item forecasting. ► We examine the superiority of the combined models by the quartile value comparison. ► Paired-sample T test is utilized to confirm the superiority of the combined models. - Abstract: For an energy-limited economy system, it is crucial to forecast load demand accurately. This paper devotes to 1-week-ahead daily load forecasting approach in which load demand series are predicted by employing the information of days before being similar to that of the forecast day. As well as in many nonlinear systems, seasonal item and trend item are coexisting in load demand datasets. In this paper, the existing of the seasonal item in the load demand data series is firstly verified according to the Kendall τ correlation testing method. Then in the belief of the separate forecasting to the seasonal item and the trend item would improve the forecasting accuracy, hybrid models by combining seasonal exponential adjustment method (SEAM) with the regression methods are proposed in this paper, where SEAM and the regression models are employed to seasonal and trend items forecasting respectively. Comparisons of the quartile values as well as the mean absolute percentage error values demonstrate this forecasting technique can significantly improve the accuracy though models applied to the trend item forecasting are eleven different ones. This superior performance of this separate forecasting technique is further confirmed by the paired-sample T tests

  12. The additive damage model: a mathematical model for cellular responses to drug combinations.

    Science.gov (United States)

    Jones, Leslie Braziel; Secomb, Timothy W; Dewhirst, Mark W; El-Kareh, Ardith W

    2014-09-21

    Mathematical models to describe dose-dependent cellular responses to drug combinations are an essential component of computational simulations for predicting therapeutic responses. Here, a new model, the additive damage model, is introduced and tested in cases where varying concentrations of two drugs are applied with a fixed exposure schedule. In the model, cell survival is determined by whether cellular damage, which depends on the concentrations of the drugs, exceeds a lethal threshold, which varies randomly in the cell population with a prescribed statistical distribution. Cellular damage is assumed to be additive, and is expressed as a sum of separate terms for each drug. Each term has a saturable dependence on drug concentration. The model has appropriate behavior over the entire range of drug concentrations, and is predictive, given single-agent dose-response data for each drug. The proposed model is compared with several other models, by testing their ability to fit 24 data sets for platinum-taxane combinations and 21 data sets for various other combinations. The Akaike Information Criterion is used to assess goodness of fit, taking into account the number of unknown parameters in each model. Overall, the additive damage model provides a better fit to the data sets than any previous model. The proposed model provides a basis for computational simulations of therapeutic responses. It predicts responses to drug combinations based on data for each drug acting as a single agent, and can be used as an improved null reference model for assessing synergy in the action of drug combinations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Ice loading model for Glacial Isostatic Adjustment in the Barents Sea constrained by GRACE gravity observations

    Science.gov (United States)

    Root, Bart; Tarasov, Lev; van der Wal, Wouter

    2014-05-01

    The global ice budget is still under discussion because the observed 120-130 m eustatic sea level equivalent since the Last Glacial Maximum (LGM) can not be explained by the current knowledge of land-ice melt after the LGM. One possible location for the missing ice is the Barents Sea Region, which was completely covered with ice during the LGM. This is deduced from relative sea level observations on Svalbard, Novaya Zemlya and the North coast of Scandinavia. However, there are no observations in the middle of the Barents Sea that capture the post-glacial uplift. With increased precision and longer time series of monthly gravity observations of the GRACE satellite mission it is possible to constrain Glacial Isostatic Adjustment in the center of the Barents Sea. This study investigates the extra constraint provided by GRACE data for modeling the past ice geometry in the Barents Sea. We use CSR release 5 data from February 2003 to July 2013. The GRACE data is corrected for the past 10 years of secular decline of glacier ice on Svalbard, Novaya Zemlya and Frans Joseph Land. With numerical GIA models for a radially symmetric Earth, we model the expected gravity changes and compare these with the GRACE observations after smoothing with a 250 km Gaussian filter. The comparisons show that for the viscosity profile VM5a, ICE-5G has too strong a gravity signal compared to GRACE. The regional calibrated ice sheet model (GLAC) of Tarasov appears to fit the amplitude of the GRACE signal. However, the GRACE data are very sensitive to the ice-melt correction, especially for Novaya Zemlya. Furthermore, the ice mass should be more concentrated to the middle of the Barents Sea. Alternative viscosity models confirm these conclusions.

  14. Modeling of Cementitious Representative Volume Element with Additives

    Science.gov (United States)

    Shahzamanian, M. M.; Basirun, W. J.

    CEMHYD3D has been employed to simulate the representative volume element (RVE) of cementitious systems (Type I cement) containing fly ash (Class F) through a voxel-based finite element analysis (FEA) approach. Three-dimensional microstructures composed of voxels are generated for a heterogeneous cementitious material consisting of various constituent phases. The primary focus is to simulate a cementitious RVE containing fly ash and to present the homogenized macromechanical properties obtained from its analysis. Simple kinematic uniform boundary conditions as well as periodic boundary conditions were imposed on the RVE to obtain the principal and shear moduli. Our current work considers the effect of fly ash percentage on the elastic properties based on the mass and volume replacements. RVEs with lengths of 50, 100 and 200μm at different degrees of hydration are generated, and the elastic properties are modeled and simulated. In general, the elastic properties of a cementitious RVE with fly ash replacement for cement based on mass and volume differ from each other. Moreover, the finite element (FE) mesh density effect is studied. Results indicate that mechanical properties decrease with increasing mesh density.

  15. Risk adjustment models for interhospital comparison of CS rates using Robson's ten group classification system and other socio-demographic and clinical variables.

    Science.gov (United States)

    Colais, Paola; Fantini, Maria P; Fusco, Danilo; Carretta, Elisa; Stivanello, Elisa; Lenzi, Jacopo; Pieri, Giulia; Perucci, Carlo A

    2012-06-21

    Caesarean section (CS) rate is a quality of health care indicator frequently used at national and international level. The aim of this study was to assess whether adjustment for Robson's Ten Group Classification System (TGCS), and clinical and socio-demographic variables of the mother and the fetus is necessary for inter-hospital comparisons of CS rates. The study population includes 64,423 deliveries in Emilia-Romagna between January 1, 2003 and December 31, 2004, classified according to theTGCS. Poisson regression was used to estimate crude and adjusted hospital relative risks of CS compared to a reference category. Analyses were carried out in the overall population and separately according to the Robson groups (groups I, II, III, IV and V-X combined). Adjusted relative risks (RR) of CS were estimated using two risk-adjustment models; the first (M1) including the TGCS group as the only adjustment factor; the second (M2) including in addition demographic and clinical confounders identified using a stepwise selection procedure. Percentage variations between crude and adjusted RRs by hospital were calculated to evaluate the confounding effect of covariates. The percentage variations from crude to adjusted RR proved to be similar in M1 and M2 model. However, stratified analyses by Robson's classification groups showed that residual confounding for clinical and demographic variables was present in groups I (nulliparous, single, cephalic, ≥37 weeks, spontaneous labour) and III (multiparous, excluding previous CS, single, cephalic, ≥37 weeks, spontaneous labour) and IV (multiparous, excluding previous CS, single, cephalic, ≥37 weeks, induced or CS before labour) and to a minor extent in groups II (nulliparous, single, cephalic, ≥37 weeks, induced or CS before labour) and IV (multiparous, excluding previous CS, single, cephalic, ≥37 weeks, induced or CS before labour). The TGCS classification is useful for inter-hospital comparison of CS section rates, but

  16. Adjusting multistate capture-recapture models for misclassification bias: manatee breeding proportions

    Science.gov (United States)

    Kendall, W.L.; Hines, J.E.; Nichols, J.D.

    2003-01-01

    Matrix population models are important tools for research and management of populations. Estimating the parameters of these models is an important step in applying them to real populations. Multistate capture-recapture methods have provided a useful means for estimating survival and parameters of transition between locations or life history states but have mostly relied on the assumption that the state occupied by each detected animal is known with certainty. Nevertheless, in some cases animals can be misclassified. Using multiple capture sessions within each period of interest, we developed a method that adjusts estimates of transition probabilities for bias due to misclassification. We applied this method to 10 years of sighting data for a population of Florida manatees (Trichechus manatus latirostris) in order to estimate the annual probability of transition from nonbreeding to breeding status. Some sighted females were unequivocally classified as breeders because they were clearly accompanied by a first-year calf. The remainder were classified, sometimes erroneously, as nonbreeders because an attendant first-year calf was not observed or was classified as more than one year old. We estimated a conditional breeding probability of 0.31 + 0.04 (estimate + 1 SE) when we ignored misclassification bias, and 0.61 + 0.09 when we accounted for misclassification.

  17. [Construction and validation of a multidimensional model of students' adjustment to college context].

    Science.gov (United States)

    Soares, Ana Paula; Guisande, M Adelina; Diniz, António M; Almeida, Leandro S

    2006-05-01

    This article presents a model of interaction of personal and contextual variables in the prediction of academic performance and psychosocial development of Portuguese college students. The sample consists of 560 first-year college students of the University of Minho. The path analysis results suggest that initial expectations of the students' involvement in academic life constituted an effective predictor of their involvement during their first year; as well as the social climate of the classroom influenced their involvement, well-being and levels of satisfaction obtained. However, these relationships were not strong enough to influence the criterion variables integrated in the model (academic performance and psychosocial development). Academic performance was predicted by the high school grades and college entrance examination scores, and the level of psychosocial development was determined by the level of development showed at the time they entered college. Though more research is needed, these results point to the importance of students' pre-college characteristics when we are considering the quality of their college adjustment process.

  18. Positive Adjustment Among American Repatriated Prisoners of the Vietnam War: Modeling the Long-Term Effects of Captivity.

    Science.gov (United States)

    King, Daniel W; King, Lynda A; Park, Crystal L; Lee, Lewina O; Kaiser, Anica Pless; Spiro, Avron; Moore, Jeffrey L; Kaloupek, Danny G; Keane, Terence M

    2015-11-01

    A longitudinal lifespan model of factors contributing to later-life positive adjustment was tested on 567 American repatriated prisoners from the Vietnam War. This model encompassed demographics at time of capture and attributes assessed after return to the U.S. (reports of torture and mental distress) and approximately 3 decades later (later-life stressors, perceived social support, positive appraisal of military experiences, and positive adjustment). Age and education at time of capture and physical torture were associated with repatriation mental distress, which directly predicted poorer adjustment 30 years later. Physical torture also had a salutary effect, enhancing later-life positive appraisals of military experiences. Later-life events were directly and indirectly (through concerns about retirement) associated with positive adjustment. Results suggest that the personal resources of older age and more education and early-life adverse experiences can have cascading effects over the lifespan to impact well-being in both positive and negative ways.

  19. Nonlinear relative-proportion-based route adjustment process for day-to-day traffic dynamics: modeling, equilibrium and stability analysis

    Science.gov (United States)

    Zhu, Wenlong; Ma, Shoufeng; Tian, Junfang; Li, Geng

    2016-11-01

    Travelers' route adjustment behaviors in a congested road traffic network are acknowledged as a dynamic game process between them. Existing Proportional-Switch Adjustment Process (PSAP) models have been extensively investigated to characterize travelers' route choice behaviors; PSAP has concise structure and intuitive behavior rule. Unfortunately most of which have some limitations, i.e., the flow over adjustment problem for the discrete PSAP model, the absolute cost differences route adjustment problem, etc. This paper proposes a relative-Proportion-based Route Adjustment Process (rePRAP) maintains the advantages of PSAP and overcomes these limitations. The rePRAP describes the situation that travelers on higher cost route switch to those with lower cost at the rate that is unilaterally depended on the relative cost differences between higher cost route and its alternatives. It is verified to be consistent with the principle of the rational behavior adjustment process. The equivalence among user equilibrium, stationary path flow pattern and stationary link flow pattern is established, which can be applied to judge whether a given network traffic flow has reached UE or not by detecting the stationary or non-stationary state of link flow pattern. The stability theorem is proved by the Lyapunov function approach. A simple example is tested to demonstrate the effectiveness of the rePRAP model.

  20. Models of traumatic experiences and children's psychological adjustment: the roles of perceived parenting and the children's own resources and activity.

    Science.gov (United States)

    Punamäki, R L; Qouta, S; el Sarraj, E

    1997-08-01

    The relations between traumatic events, perceived parenting styles, children's resources, political activity, and psychological adjustment were examined among 108 Palestinian boys and girls of 11-12 years of age. The results showed that exposure to traumatic events increased psychological adjustment problems directly and via 2 mediating paths. First, the more traumatic events children had experienced, the more negative parenting they experienced. And, the poorer they perceived parenting, the more they suffered from high neuroticism and low self-esteem. Second, the more traumatic events children had experienced, the more political activity they showed, and the more active they were, the more they suffered from psychological adjustment problems. Good perceived parenting protected children's psychological adjustment by making them less vulnerable in two ways. First, traumatic events decreased their intellectual, creative, and cognitive resources, and a lack of resources predicted many psychological adjustment problems in a model excluding perceived parenting. Second, political activity increased psychological adjustment problems in the same model, but not in the model including good parenting.

  1. Adjustable collimator

    International Nuclear Information System (INIS)

    Carlson, R.W.; Covic, J.; Leininger, G.

    1981-01-01

    In a rotating fan beam tomographic scanner there is included an adjustable collimator and shutter assembly. The assembly includes a fan angle collimation cylinder having a plurality of different length slots through which the beam may pass for adjusting the fan angle of the beam. It also includes a beam thickness cylinder having a plurality of slots of different widths for adjusting the thickness of the beam. Further, some of the slots have filter materials mounted therein so that the operator may select from a plurality of filters. Also disclosed is a servo motor system which allows the operator to select the desired fan angle, beam thickness and filter from a remote location. An additional feature is a failsafe shutter assembly which includes a spring biased shutter cylinder mounted in the collimation cylinders. The servo motor control circuit checks several system conditions before the shutter is rendered openable. Further, the circuit cuts off the radiation if the shutter fails to open or close properly. A still further feature is a reference radiation intensity monitor which includes a tuning-fork shaped light conducting element having a scintillation crystal mounted on each tine. The monitor is placed adjacent the collimator between it and the source with the pair of crystals to either side of the fan beam

  2. Assessment of regression models for adjustment of iron status biomarkers for inflammation in children with moderate acute malnutrition in Burkina Faso

    DEFF Research Database (Denmark)

    Cichon, Bernardette; Ritz, Christian; Fabiansen, Christian

    2017-01-01

    and morbidity covariates (model 3) as predictors. The predictive performance of the models was compared with the use of 10-fold crossvalidation and quantified with the use of root mean square errors (RMSEs). SF and sTfR were adjusted with the use of regression coefficients from linear models. RESULTS......BACKGROUND: Biomarkers of iron status are affected by inflammation. In order to interpret them in individuals with inflammation, the use of correction factors (CFs) has been proposed. OBJECTIVE: The objective of this study was to investigate the use of regression models as an alternative to the CF...... measured in serum. Generalized additive, quadratic, and linear models were used to model the relation between SF and sTfR as outcomes and CRP and AGP as categorical variables (model 1; equivalent to the CF approach), CRP and AGP as continuous variables (model 2), or CRP and AGP as continuous variables...

  3. Assessing climate change effects on long-term forest development: adjusting growth, phenology, and seed production in a gap model

    NARCIS (Netherlands)

    Meer, van der P.J.; Jorritsma, I.T.M.; Kramer, K.

    2002-01-01

    The sensitivity of forest development to climate change is assessed using a gap model. Process descriptions in the gap model of growth, phenology, and seed production were adjusted for climate change effects using a detailed process-based growth modeland a regression analysis. Simulation runs over

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

    Directory of Open Access Journals (Sweden)

    Yun Shi

    2014-01-01

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

  5. Modeling and Dynamic Simulation of the Adjust and Control System Mechanism for Reactor CAREM-25

    International Nuclear Information System (INIS)

    Larreteguy, A.E; Mazufri, C.M

    2000-01-01

    The adjust and control system mechanism, MSAC, is an advanced, and in some senses unique, hydromechanical device.The efforts in modeling this mechanism are aimed to: Get a deep understanding of the physical phenomena involved,Identify the set of parameters relevant to the dynamics of the system,Allow the numerical simulation of the system,Predict the behavior of the mechanism in conditions other than that obtainable within the range of operation of the experimental setup (CEM), and Help in defining the design of the CAPEM (loop for testing the mechanism under high pressure/high temperature conditions).Thanks to the close interaction between the mechanics, the experimenters, and the modelists that compose the MSAC task force, it has been possible to suggest improvements, not only in the design of the mechanism, but also in the design and the operation of the pulse generator (GDP) and the rest of the CEM.This effort has led to a design mature enough so as to be tested in a high-pressure loop

  6. [Structural adjustment, cultural adjustment?].

    Science.gov (United States)

    Dujardin, B; Dujardin, M; Hermans, I

    2003-12-01

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

  7. Adjustments of the TaD electron density reconstruction model with GNSS-TEC parameters for operational application purposes

    Directory of Open Access Journals (Sweden)

    Belehaki Anna

    2012-12-01

    Full Text Available Validation results on the latest version of TaD model (TaDv2 show realistic reconstruction of the electron density profiles (EDPs with an average error of 3 TECU, similar to the error obtained from GNSS-TEC calculated paremeters. The work presented here has the aim to further improve the accuracy of the TaD topside reconstruction, adjusting the TEC parameter calculated from TaD model with the TEC parameter calculated by GNSS transmitting RINEX files provided by receivers co-located with the Digisondes. The performance of the new version is tested during a storm period demonstrating further improvements in respect to the previous version. Statistical comparison of modeled and observed TEC confirms the validity of the proposed adjustment. A significant benefit of the proposed upgrade is that it facilitates the real-time implementation of TaD. The model needs a reliable measure of the scale height at the peak height, which is supposed to be provided by Digisondes. Oftenly, the automatic scaling software fails to correctly calculate the scale height at the peak, Hm, due to interferences in the receiving signal. Consequently the model estimated topside scale height is wrongly calculated leading to unrealistic results for the modeled EDP. The proposed TEC adjustment forces the model to correctly reproduce the topside scale height, despite the inaccurate values of Hm. This adjustment is very important for the application of TaD in an operational environment.

  8. Age-related change in Wechsler IQ norms after adjustment for the Flynn effect: estimates from three computational models.

    Science.gov (United States)

    Agbayani, Kristina A; Hiscock, Merrill

    2013-01-01

    A previous study found that the Flynn effect accounts for 85% of the normative difference between 20- and 70-year-olds on subtests of the Wechsler intelligence tests. Adjusting scores for the Flynn effect substantially reduces normative age-group differences, but the appropriate amount of adjustment is uncertain. The present study replicates previous findings and employs two other methods of adjusting for the Flynn effect. Averaged across models, results indicate that the Flynn effect accounts for 76% of normative age-group differences on Wechsler IQ subtests. Flynn-effect adjustment reduces the normative age-related decline in IQ from 4.3 to 1.1 IQ points per decade.

  9. Effect of the spray volume adjustment model on the efficiency of fungicides and residues in processing tomato

    Directory of Open Access Journals (Sweden)

    Henryk Ratajkiewicz

    2016-08-01

    Full Text Available This study compared the effects of a proportionate spray volume (PSV adjustment model and a fixed model (300 L/ha on the infestation of processing tomato with potato late blight (Phytophthora infestans (Mont. de Bary (PLB and azoxystrobin and chlorothalonil residues in fruits in three consecutive seasons. The fungicides were applied in alternating system with or without two spreader adjuvants. The proportionate spray volume adjustment model was based on the number of leaves on plants and spray volume index. The modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS method was optimized and validated for extraction of azoxystrobin and chlorothalonil residue. Gas chromatography with a nitrogen and phosphorus detector and an electron capture detector were used for the analysis of fungicides. The results showed that higher fungicidal residues were connected with lower infestation of tomato with PLB. PSV adjustment model resulted in lower infestation of tomato than the fixed model (300 L/ha when fungicides were applied at half the dose without adjuvants. Higher expected spray interception into the tomato canopy with the PSV system was recognized as the reasons of better control of PLB. The spreader adjuvants did not have positive effect on the biological efficacy of spray volume application systems. The results suggest that PSV adjustment model can be used to determine the spray volume for fungicide application for processing tomato crop.

  10. Effect of the spray volume adjustment model on the efficiency of fungicides and residues in processing tomato

    Energy Technology Data Exchange (ETDEWEB)

    Ratajkiewicz, H.; Kierzek, R.; Raczkowski, M.; Hołodyńska-Kulas, A.; Łacka, A.; Wójtowicz, A.; Wachowiak, M.

    2016-11-01

    This study compared the effects of a proportionate spray volume (PSV) adjustment model and a fixed model (300 L/ha) on the infestation of processing tomato with potato late blight (Phytophthora infestans (Mont.) de Bary) (PLB) and azoxystrobin and chlorothalonil residues in fruits in three consecutive seasons. The fungicides were applied in alternating system with or without two spreader adjuvants. The proportionate spray volume adjustment model was based on the number of leaves on plants and spray volume index. The modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was optimized and validated for extraction of azoxystrobin and chlorothalonil residue. Gas chromatography with a nitrogen and phosphorus detector and an electron capture detector were used for the analysis of fungicides. The results showed that higher fungicidal residues were connected with lower infestation of tomato with PLB. PSV adjustment model resulted in lower infestation of tomato than the fixed model (300 L/ha) when fungicides were applied at half the dose without adjuvants. Higher expected spray interception into the tomato canopy with the PSV system was recognized as the reasons of better control of PLB. The spreader adjuvants did not have positive effect on the biological efficacy of spray volume application systems. The results suggest that PSV adjustment model can be used to determine the spray volume for fungicide application for processing tomato crop. (Author)

  11. Opportunities for Improving Army Modeling and Simulation Development: Making Fundamental Adjustments and Borrowing Commercial Business Practices

    National Research Council Canada - National Science Library

    Lee, John

    2000-01-01

    ...; requirements which span the conflict spectrum. The Army's current staff training simulation development process could better support all possible scenarios by making some fundamental adjustments and borrowing commercial business practices...

  12. Using Multilevel Modeling to Assess Case-Mix Adjusters in Consumer Experience Surveys in Health Care

    NARCIS (Netherlands)

    Damman, Olga C.; Stubbe, Janine H.; Hendriks, Michelle; Arah, Onyebuchi A.; Spreeuwenberg, Peter; Delnoij, Diana M. J.; Groenewegen, Peter P.

    2009-01-01

    Background: Ratings on the quality of healthcare from the consumer's perspective need to be adjusted for consumer characteristics to ensure fair and accurate comparisons between healthcare providers or health plans. Although multilevel analysis is already considered an appropriate method for

  13. [Error structure and additivity of individual tree biomass model for four natural conifer species in Northeast China].

    Science.gov (United States)

    Dogn, Li-hu; Li, Feng-ri; Song, Yu-wen

    2015-03-01

    Based on the biomass data of 276 sampling trees of Pinus koraiensis, Abies nephrolepis, Picea koraiensis and Larix gmelinii, the mono-element and dual-element additive system of biomass equations for the four conifer species was developed. The model error structure (additive vs. multiplicative) of the allometric equation was evaluated using the likelihood analysis, while nonlinear seemly unrelated regression was used to estimate the parameters in the additive system of biomass equations. The results indicated that the assumption of multiplicative error structure was strongly supported for the biomass equations of total and tree components for the four conifer species. Thus, the additive system of log-transformed biomass equations was developed. The adjusted coefficient of determination (Ra 2) of the additive system of biomass equations for the four conifer species was 0.85-0.99, the mean relative error was between -7.7% and 5.5%, and the mean absolute relative error was less than 30.5%. Adding total tree height in the additive systems of biomass equations could significantly improve model fitting performance and predicting precision, and the biomass equations of total, aboveground and stem were better than biomass equations of root, branch, foliage and crown. The precision of each biomass equation in the additive system varied from 77.0% to 99.7% with a mean value of 92.3% that would be suitable for predicting the biomass of the four natural conifer species.

  14. Modelling time course gene expression data with finite mixtures of linear additive models.

    Science.gov (United States)

    Grün, Bettina; Scharl, Theresa; Leisch, Friedrich

    2012-01-15

    A model class of finite mixtures of linear additive models is presented. The component-specific parameters in the regression models are estimated using regularized likelihood methods. The advantages of the regularization are that (i) the pre-specified maximum degrees of freedom for the splines is less crucial than for unregularized estimation and that (ii) for each component individually a suitable degree of freedom is selected in an automatic way. The performance is evaluated in a simulation study with artificial data as well as on a yeast cell cycle dataset of gene expression levels over time. The latest release version of the R package flexmix is available from CRAN (http://cran.r-project.org/).

  15. Risk-adjustment models for heart failure patients' 30-day mortality and readmission rates: the incremental value of clinical data abstracted from medical charts beyond hospital discharge record.

    Science.gov (United States)

    Lenzi, Jacopo; Avaldi, Vera Maria; Hernandez-Boussard, Tina; Descovich, Carlo; Castaldini, Ilaria; Urbinati, Stefano; Di Pasquale, Giuseppe; Rucci, Paola; Fantini, Maria Pia

    2016-09-06

    Hospital discharge records (HDRs) are routinely used to assess outcomes of care and to compare hospital performance for heart failure. The advantages of using clinical data from medical charts to improve risk-adjustment models remain controversial. The aim of the present study was to evaluate the additional contribution of clinical variables to HDR-based 30-day mortality and readmission models in patients with heart failure. This retrospective observational study included all patients residing in the Local Healthcare Authority of Bologna (about 1 million inhabitants) who were discharged in 2012 from one of three hospitals in the area with a diagnosis of heart failure. For each study outcome, we compared the discrimination of the two risk-adjustment models (i.e., HDR-only model and HDR-clinical model) through the area under the ROC curve (AUC). A total of 1145 and 1025 patients were included in the mortality and readmission analyses, respectively. Adding clinical data significantly improved the discrimination of the mortality model (AUC = 0.84 vs. 0.73, p < 0.001), but not the discrimination of the readmission model (AUC = 0.65 vs. 0.63, p = 0.08). We identified clinical variables that significantly improved the discrimination of the HDR-only model for 30-day mortality following heart failure. By contrast, clinical variables made little contribution to the discrimination of the HDR-only model for 30-day readmission.

  16. DaMoScope and its internet graphics for the visual control of adjusting mathematical models describing experimental data

    International Nuclear Information System (INIS)

    Belousov, V. I.; Ezhela, V. V.; Kuyanov, Yu. V.; Tkachenko, N. P.

    2015-01-01

    The experience of using the dynamic atlas of the experimental data and mathematical models of their description in the problems of adjusting parametric models of observable values depending on kinematic variables is presented. The functional possibilities of an image of a large number of experimental data and the models describing them are shown by examples of data and models of observable values determined by the amplitudes of elastic scattering of hadrons. The Internet implementation of an interactive tool DaMoScope and its interface with the experimental data and codes of adjusted parametric models with the parameters of the best description of data are schematically shown. The DaMoScope codes are freely available

  17. DaMoScope and its internet graphics for the visual control of adjusting mathematical models describing experimental data

    Science.gov (United States)

    Belousov, V. I.; Ezhela, V. V.; Kuyanov, Yu. V.; Tkachenko, N. P.

    2015-12-01

    The experience of using the dynamic atlas of the experimental data and mathematical models of their description in the problems of adjusting parametric models of observable values depending on kinematic variables is presented. The functional possibilities of an image of a large number of experimental data and the models describing them are shown by examples of data and models of observable values determined by the amplitudes of elastic scattering of hadrons. The Internet implementation of an interactive tool DaMoScope and its interface with the experimental data and codes of adjusted parametric models with the parameters of the best description of data are schematically shown. The DaMoScope codes are freely available.

  18. Constraints of GRACE on the Ice Model and Mantle Rheology in Glacial Isostatic Adjustment Modeling in North-America

    Science.gov (United States)

    van der Wal, W.; Wu, P.; Sideris, M.; Wang, H.

    2009-05-01

    GRACE satellite data offer homogeneous coverage of the area covered by the former Laurentide ice sheet. The secular gravity rate estimated from the GRACE data can therefore be used to constrain the ice loading history in Laurentide and, to a lesser extent, the mantle rheology in a GIA model. The objective of this presentation is to find a best fitting global ice model and use it to study how the ice model can be modified to fit a composite rheology, in which creep rates from a linear and non-linear rheology are added. This is useful because all the ice models constructed from GIA assume that mantle rheology is linear, but creep experiments on rocks show that nonlinear rheology may be the dominant mechanism in some parts of the mantle. We use CSR release 4 solutions from August 2002 to October 2008 with continental water storage effects removed by the GLDAS model and filtering with a destriping and Gaussian filter. The GIA model is a radially symmetric incompressible Maxwell Earth, with varying upper and lower mantle viscosity. Gravity rate misfit values are computed for with a range of viscosity values with the ICE-3G, ICE-4G and ICE-5G models. The best fit is shown for models with ICE-3G and ICE-4G, and the ICE-4G model is selected for computations with a so-called composite rheology. For the composite rheology, the Coupled Laplace Finite-Element Method is used to compute the GIA response of a spherical self-gravitating incompressible Maxwell Earth. The pre-stress exponent (A) derived from a uni- axial stress experiment is varied between 3.3 x 10-34/10-35/10-36 Pa-3s-1, the Newtonian viscosity η is varied between 1 and 3 x 1021 Pa-s, and the stress exponent is taken to be 3. Composite rheology in general results in geoid rates that are too small compared to GRACE observations. Therefore, simple modifications of the ICE-4G history are investigated by scaling ice heights or delaying glaciation. It is found that a delay in glaciation is a better way to adjust ice

  19. Additional double-wall roof in single-wall, closed, convective incubators: Impact on body heat loss from premature infants and optimal adjustment of the incubator air temperature.

    Science.gov (United States)

    Delanaud, Stéphane; Decima, Pauline; Pelletier, Amandine; Libert, Jean-Pierre; Stephan-Blanchard, Erwan; Bach, Véronique; Tourneux, Pierre

    2016-09-01

    Radiant heat loss is high in low-birth-weight (LBW) neonates. Double-wall or single-wall incubators with an additional double-wall roof panel that can be removed during phototherapy are used to reduce Radiant heat loss. There are no data on how the incubators should be used when this second roof panel is removed. The aim of the study was to assess the heat exchanges in LBW neonates in a single-wall incubator with and without an additional roof panel. To determine the optimal thermoneutral incubator air temperature. Influence of the additional double-wall roof was assessed by using a thermal mannequin simulating a LBW neonate. Then, we calculated the optimal incubator air temperature from a cohort of human LBW neonate in the absence of the additional roof panel. Twenty-three LBW neonates (birth weight: 750-1800g; gestational age: 28-32 weeks) were included. With the additional roof panel, R was lower but convective and evaporative skin heat losses were greater. This difference can be overcome by increasing the incubator air temperature by 0.15-0.20°C. The benefit of an additional roof panel was cancelled out by greater body heat losses through other routes. Understanding the heat transfers between the neonate and the environment is essential for optimizing incubators. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. A rainfall disaggregation scheme for sub-hourly time scales: Coupling a Bartlett-Lewis based model with adjusting procedures

    Science.gov (United States)

    Kossieris, Panagiotis; Makropoulos, Christos; Onof, Christian; Koutsoyiannis, Demetris

    2018-01-01

    Many hydrological applications, such as flood studies, require the use of long rainfall data at fine time scales varying from daily down to 1 min time step. However, in the real world there is limited availability of data at sub-hourly scales. To cope with this issue, stochastic disaggregation techniques are typically employed to produce possible, statistically consistent, rainfall events that aggregate up to the field data collected at coarser scales. A methodology for the stochastic disaggregation of rainfall at fine time scales was recently introduced, combining the Bartlett-Lewis process to generate rainfall events along with adjusting procedures to modify the lower-level variables (i.e., hourly) so as to be consistent with the higher-level one (i.e., daily). In the present paper, we extend the aforementioned scheme, initially designed and tested for the disaggregation of daily rainfall into hourly depths, for any sub-hourly time scale. In addition, we take advantage of the recent developments in Poisson-cluster processes incorporating in the methodology a Bartlett-Lewis model variant that introduces dependence between cell intensity and duration in order to capture the variability of rainfall at sub-hourly time scales. The disaggregation scheme is implemented in an R package, named HyetosMinute, to support disaggregation from daily down to 1-min time scale. The applicability of the methodology was assessed on a 5-min rainfall records collected in Bochum, Germany, comparing the performance of the above mentioned model variant against the original Bartlett-Lewis process (non-random with 5 parameters). The analysis shows that the disaggregation process reproduces adequately the most important statistical characteristics of rainfall at wide range of time scales, while the introduction of the model with dependent intensity-duration results in a better performance in terms of skewness, rainfall extremes and dry proportions.

  1. Method for mapping population-based case-control studies: an application using generalized additive models

    Directory of Open Access Journals (Sweden)

    Aschengrau Ann

    2006-06-01

    Full Text Available Abstract Background Mapping spatial distributions of disease occurrence and risk can serve as a useful tool for identifying exposures of public health concern. Disease registry data are often mapped by town or county of diagnosis and contain limited data on covariates. These maps often possess poor spatial resolution, the potential for spatial confounding, and the inability to consider latency. Population-based case-control studies can provide detailed information on residential history and covariates. Results Generalized additive models (GAMs provide a useful framework for mapping point-based epidemiologic data. Smoothing on location while controlling for covariates produces adjusted maps. We generate maps of odds ratios using the entire study area as a reference. We smooth using a locally weighted regression smoother (loess, a method that combines the advantages of nearest neighbor and kernel methods. We choose an optimal degree of smoothing by minimizing Akaike's Information Criterion. We use a deviance-based test to assess the overall importance of location in the model and pointwise permutation tests to locate regions of significantly increased or decreased risk. The method is illustrated with synthetic data and data from a population-based case-control study, using S-Plus and ArcView software. Conclusion Our goal is to develop practical methods for mapping population-based case-control and cohort studies. The method described here performs well for our synthetic data, reproducing important features of the data and adequately controlling the covariate. When applied to the population-based case-control data set, the method suggests spatial confounding and identifies statistically significant areas of increased and decreased odds ratios.

  2. Development of a Risk-adjustment Model for the Inpatient Rehabilitation Facility Discharge Self-care Functional Status Quality Measure.

    Science.gov (United States)

    Deutsch, Anne; Pardasaney, Poonam; Iriondo-Perez, Jeniffer; Ingber, Melvin J; Porter, Kristie A; McMullen, Tara

    2017-07-01

    Functional status measures are important patient-centered indicators of inpatient rehabilitation facility (IRF) quality of care. We developed a risk-adjusted self-care functional status measure for the IRF Quality Reporting Program. This paper describes the development and performance of the measure's risk-adjustment model. Our sample included IRF Medicare fee-for-service patients from the Centers for Medicare & Medicaid Services' 2008-2010 Post-Acute Care Payment Reform Demonstration. Data sources included the Continuity Assessment Record and Evaluation Item Set, IRF-Patient Assessment Instrument, and Medicare claims. Self-care scores were based on 7 Continuity Assessment Record and Evaluation items. The model was developed using discharge self-care score as the dependent variable, and generalized linear modeling with generalized estimation equation to account for patient characteristics and clustering within IRFs. Patient demographics, clinical characteristics at IRF admission, and clinical characteristics related to the recent hospitalization were tested as risk adjusters. A total of 4769 patient stays from 38 IRFs were included. Approximately 57% of the sample was female; 38.4%, 75-84 years; and 31.0%, 65-74 years. The final model, containing 77 risk adjusters, explained 53.7% of variance in discharge self-care scores (Pcare function was the strongest predictor, followed by admission cognitive function and IRF primary diagnosis group. The range of expected and observed scores overlapped very well, with little bias across the range of predicted self-care functioning. Our risk-adjustment model demonstrated strong validity for predicting discharge self-care scores. Although the model needs validation with national data, it represents an important first step in evaluation of IRF functional outcomes.

  3. Adjust cut-off values of immunohistochemistry models to predict risk of distant recurrence in invasive breast carcinoma patients

    Directory of Open Access Journals (Sweden)

    Yen-Ying Chen

    2016-12-01

    Conclusion: It is necessary to adjust the cut-off values of IHC-based prognostic models to fit the purpose. If the estimated risk is clearly high or low, it may be reasonable to omit multigene assays when cost is a consideration.

  4. Patterns of Children's Adrenocortical Reactivity to Interparental Conflict and Associations with Child Adjustment: A Growth Mixture Modeling Approach

    Science.gov (United States)

    Koss, Kalsea J.; George, Melissa R. W.; Davies, Patrick T.; Cicchetti, Dante; Cummings, E. Mark; Sturge-Apple, Melissa L.

    2013-01-01

    Examining children's physiological functioning is an important direction for understanding the links between interparental conflict and child adjustment. Utilizing growth mixture modeling, the present study examined children's cortisol reactivity patterns in response to a marital dispute. Analyses revealed three different patterns of cortisol…

  5. Modeling of Autovariator Operation as Power Components Adjuster in Adaptive Machine Drives

    Science.gov (United States)

    Balakin, P. D.; Belkov, V. N.; Shtripling, L. O.

    2018-01-01

    Full application of the available power and stationary mode preservation for the power station (engine) operation of the transport machine under the conditions of variable external loading, are topical issues. The issues solution is possible by means of mechanical drives with the autovaried rate transfer function and nonholonomic constraint of the main driving mediums. Additional to the main motion, controlled motion of the driving mediums is formed by a variable part of the transformed power flow and is implemented by the integrated control loop, functioning only on the basis of the laws of motion. The mathematical model of the mechanical autovariator operation is developed using Gibbs function, acceleration energy; the study results are presented; on their basis, the design calculations of the autovariator driving mediums and constraints, including its automatic control loop, are possible.

  6. Multiple High-Fidelity Modeling Tools for Metal Additive Manufacturing Process Development, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Despite the rapid commercialization of additive manufacturing technology such as selective laser melting, SLM, there are gaps in process modeling and material...

  7. Multiple High-Fidelity Modeling Tools for Metal Additive Manufacturing Process Development, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Despite the rapid commercialization of additive manufacturing technology such as selective laser melting, SLM, there are gaps in process modeling and material...

  8. Eurodollar futures and options: convexity adjustment in HJM one- factor model

    OpenAIRE

    Henrard Marc

    2005-01-01

    In this note we give pricing formulas for different instruments linked to rate futures (euro-dollar futures). We provide the future price including the convexity adjustment and the exact dates. Based on that result we price options on futures, including the mid-curve options.

  9. Using multilevel modelling to assess case-mix adjusters in consumers experience surveys in health care

    NARCIS (Netherlands)

    Damman, O.C.; Stubbe, J.H.; Hendriks, M.; Arah, O.A.; Spreeuwenberg, P.; Delnoij, D.M.J.; Groenewegen, P.P.

    2009-01-01

    Background: Ratings on the quality of healthcare from the consumer’s perspective need to be adjusted for consumer characteristics to ensure fair and accurate comparisons between healthcare providers or health plans. Although multilevel analysis is already considered an appropriate method for

  10. Using multilevel modeling to assess case-mix adjusters in consumer experience surveys in health care.

    NARCIS (Netherlands)

    Damman, O.C.; Stubbe, J.H.; Hendriks, M.; Arah, O.A.; Spreeuwenberg, P.; Delnoij, D.M.J.; Groenewegen, P.P.

    2009-01-01

    Background: Ratings on the quality of healthcare from the consumer’s perspective need to be adjusted for consumer characteristics to ensure fair and accurate comparisons between healthcare providers or health plans. Although multilevel analysis is already considered an appropriate method for

  11. Convexity Adjustments

    DEFF Research Database (Denmark)

    M. Gaspar, Raquel; Murgoci, Agatha

    2010-01-01

    A convexity adjustment (or convexity correction) in fixed income markets arises when one uses prices of standard (plain vanilla) products plus an adjustment to price nonstandard products. We explain the basic and appealing idea behind the use of convexity adjustments and focus on the situations...

  12. Individual-level space-time analyses of emergency department data using generalized additive modeling

    Directory of Open Access Journals (Sweden)

    Vieira Verónica M

    2012-08-01

    Full Text Available Abstract Background Although daily emergency department (ED data is a source of information that often includes residence, its potential for space-time analyses at the individual level has not been fully explored. We propose that ED data collected for surveillance purposes can also be used to inform spatial and temporal patterns of disease using generalized additive models (GAMs. This paper describes the methods for adapting GAMs so they can be applied to ED data. Methods GAMs are an effective approach for modeling spatial and temporal distributions of point-wise data, producing smoothed surfaces of continuous risk while adjusting for confounders. In addition to disease mapping, the method allows for global and pointwise hypothesis testing and selection of statistically optimum degree of smoothing using standard statistical software. We applied a two-dimensional GAM for location to ED data of overlapping calendar time using a locally-weighted regression smoother. To illustrate our methods, we investigated the association between participants’ address and the risk of gastrointestinal illness in Cape Cod, Massachusetts over time. Results The GAM space-time analyses simultaneously smooth in units of distance and time by using the optimum degree of smoothing to create data frames of overlapping time periods and then spatially analyzing each data frame. When resulting maps are viewed in series, each data frame contributes a movie frame, allowing us to visualize changes in magnitude, geographic size, and location of elevated risk smoothed over space and time. In our example data, we observed an underlying geographic pattern of gastrointestinal illness with risks consistently higher in the eastern part of our study area over time and intermittent variations of increased risk during brief periods. Conclusions Spatial-temporal analysis of emergency department data with GAMs can be used to map underlying disease risk at the individual-level and view

  13. Additive Manufacturing Modeling and Simulation A Literature Review for Electron Beam Free Form Fabrication

    Science.gov (United States)

    Seufzer, William J.

    2014-01-01

    Additive manufacturing is coming into industrial use and has several desirable attributes. Control of the deposition remains a complex challenge, and so this literature review was initiated to capture current modeling efforts in the field of additive manufacturing. This paper summarizes about 10 years of modeling and simulation related to both welding and additive manufacturing. The goals were to learn who is doing what in modeling and simulation, to summarize various approaches taken to create models, and to identify research gaps. Later sections in the report summarize implications for closed-loop-control of the process, implications for local research efforts, and implications for local modeling efforts.

  14. Stiffness Model of a 3-DOF Parallel Manipulator with Two Additional Legs

    Directory of Open Access Journals (Sweden)

    Guang Yu

    2014-10-01

    Full Text Available This paper investigates the stiffness modelling of a 3-DOF parallel manipulator with two additional legs. The stiffness model in six directions of the 3-DOF parallel manipulator with two additional legs is derived by performing condensation of DOFs for the joint connection and treatment of the fixed-end connections. Moreover, this modelling method is used to derive the stiffness model of the manipulator with zero/one additional legs. Two performance indices are given to compare the stiffness of the parallel manipulators with two additional legs with those of the manipulators with zero/one additional legs. The method not only can be used to derive the stiffness model of a redundant parallel manipulator, but also to model the stiffness of non-redundant parallel manipulators.

  15. Filling Gaps in the Acculturation Gap-Distress Model: Heritage Cultural Maintenance and Adjustment in Mexican-American Families.

    Science.gov (United States)

    Telzer, Eva H; Yuen, Cynthia; Gonzales, Nancy; Fuligni, Andrew J

    2016-07-01

    The acculturation gap-distress model purports that immigrant children acculturate faster than do their parents, resulting in an acculturation gap that leads to family and youth maladjustment. However, empirical support for the acculturation gap-distress model has been inconclusive. In the current study, 428 Mexican-American adolescents (50.2 % female) and their primary caregivers independently completed questionnaires assessing their levels of American and Mexican cultural orientation, family functioning, and youth adjustment. Contrary to the acculturation gap-distress model, acculturation gaps were not associated with poorer family or youth functioning. Rather, adolescents with higher levels of Mexican cultural orientations showed positive outcomes, regardless of their parents' orientations to either American or Mexican cultures. Findings suggest that youths' heritage cultural maintenance may be most important for their adjustment.

  16. Holocene sea-level changes along the North Carolina Coastline and their implications for glacial isostatic adjustment models

    Science.gov (United States)

    Horton, B. P.; Peltier, W. R.; Culver, S. J.; Drummond, R.; Engelhart, S. E.; Kemp, A. C.; Mallinson, D.; Thieler, E. R.; Riggs, S. R.; Ames, D. V.; Thomson, K. H.

    2009-08-01

    We have synthesized new and existing relative sea-level (RSL) data to produce a quality-controlled, spatially comprehensive database from the North Carolina coastline. The RSL database consists of 54 sea-level index points that are quantitatively related to an appropriate tide level and assigned an error estimate, and a further 33 limiting dates that confine the maximum and minimum elevations of RSL. The temporal distribution of the index points is very uneven with only five index points older than 4000 cal a BP, but the form of the Holocene sea-level trend is constrained by both terrestrial and marine limiting dates. The data illustrate RSL rapidly rising during the early and mid Holocene from an observed elevation of -35.7 ± 1.1 m MSL at 11062-10576 cal a BP to -4.2 m ± 0.4 m MSL at 4240-3592 cal a BP. We restricted comparisons between observations and predictions from the ICE-5G(VM2) with rotational feedback Glacial Isostatic Adjustment (GIA) model to the Late Holocene RSL (last 4000 cal a BP) because of the wealth of sea-level data during this time interval. The ICE-5G(VM2) model predicts significant spatial variations in RSL across North Carolina, thus we subdivided the observations into two regions. The model forecasts an increase in the rate of sea-level rise in Region 1 (Albemarle, Currituck, Roanoke, Croatan, and northern Pamlico sounds) compared to Region 2 (southern Pamlico, Core and Bogue sounds, and farther south to Wilmington). The observations show Late Holocene sea-level rising at 1.14 ± 0.03 mm year -1 and 0.82 ± 0.02 mm year -1 in Regions 1 and 2, respectively. The ICE-5G(VM2) predictions capture the general temporal trend of the observations, although there is an apparent misfit for index points older than 2000 cal a BP. It is presently unknown whether these misfits are caused by possible tectonic uplift associated with the mid-Carolina Platform High or a flaw in the GIA model. A comparison of local tide gauge data with the Late Holocene RSL

  17. The Long-Standing Antarctic Mantle Plume Hypothesis and Modeling Ongoing Glacial Isostatic Adjustment

    Science.gov (United States)

    Ivins, E. R.; Seroussi, H. L.; Wiens, D.; Larour, E. Y.

    2016-12-01

    Alkaline basalts of the Marie Byrd Land (MBL) have been interpreted as evidence of a mantle plume impinging on the lithosphere from below at about 85-80 Ma and again at 30-20 Ma. Because of the lack of structural and stratigraphic mapping due to ice sheet cover, and even a general lack of sufficient bottom topography, it is impossible to identify and classify the main characteristics of such a putative plume with respect to ones that are well-studied, such as the Yellowstone or Raton hotspots. Recent POLENET seismic mapping has identified possible plume structures that could extend across the upper mantle beneath the Ruppert Coast (RC) in southeast MBL, and possible plume beneath the Bentley Subglacial Trench (BST), some 1000 km to the southwest of RC, and on the opposite side of MBL. Mapping of subglacial lakes via altimetry allows reconstruction of basal conditions that are consistent with melt generation rates and patterns of basal water routing. We extensively model the hotspot heat flux caused by a plume buried beneath the crust of the West Antarctic Ice Sheet (WAIS) and employing set of 3-D thermomechanical Stokes flow simulations with the Ice Sheet System Model (ISSM). We discover that a mantle upwelling structure beneath the BST, upstream of Subglacial Lake Whillans (SLW) and Whillans Ice Stream is compatible when the peak plume-related geothermal heat flux, qGHF, approaches 200 mW/m^2, rather consistent with heat flux measurements at the WISSARD core site where heat flux probes penetrated into sediments of SLW. For a plume at RC the ISSM predictions do allow a plume, consistent with seismic mapping, but require the peak plume flux to be upper bound by qGHF ≤ 150 mW/m^2. New maps of the relatively slower upper mantle shear wave velocity beneath WAIS reveal that the slowest velocity corresponds to mantle below MLB. Using our new constraints on a 3-D plume interpretation of this slowness, we determine the perturbations to GIA modeling that are required to

  18. An introduction to modeling longitudinal data with generalized additive models: applications to single-case designs.

    Science.gov (United States)

    Sullivan, Kristynn J; Shadish, William R; Steiner, Peter M

    2015-03-01

    Single-case designs (SCDs) are short time series that assess intervention effects by measuring units repeatedly over time in both the presence and absence of treatment. This article introduces a statistical technique for analyzing SCD data that has not been much used in psychological and educational research: generalized additive models (GAMs). In parametric regression, the researcher must choose a functional form to impose on the data, for example, that trend over time is linear. GAMs reverse this process by letting the data inform the choice of functional form. In this article we review the problem that trend poses in SCDs, discuss how current SCD analytic methods approach trend, describe GAMs as a possible solution, suggest a GAM model testing procedure for examining the presence of trend in SCDs, present a small simulation to show the statistical properties of GAMs, and illustrate the procedure on 3 examples of different lengths. Results suggest that GAMs may be very useful both as a form of sensitivity analysis for checking the plausibility of assumptions about trend and as a primary data analysis strategy for testing treatment effects. We conclude with a discussion of some problems with GAMs and some future directions for research on the application of GAMs to SCDs. (c) 2015 APA, all rights reserved).

  19. Different Effect of the Additional Electron-Withdrawing Cyano Group in Different Conjugation Bridge: The Adjusted Molecular Energy Levels and Largely Improved Photovoltaic Performance.

    Science.gov (United States)

    Li, Huiyang; Fang, Manman; Hou, Yingqin; Tang, Runli; Yang, Yizhou; Zhong, Cheng; Li, Qianqian; Li, Zhen

    2016-05-18

    Four organic sensitizers (LI-68-LI-71) bearing various conjugated bridges were designed and synthesized, in which the only difference between LI-68 and LI-69 (or LI-70 and LI-71) was the absence/presence of the CN group as the auxiliary electron acceptor. Interestingly, compared to the reference dye of LI-68, LI-69 bearing the additional CN group exhibited the bad performance with the decreased Jsc and Voc values. However, once one thiophene moiety near the anchor group was replaced by pyrrole with the electron-rich property, the resultant LI-71 exhibited a photoelectric conversion efficiency increase by about 3 folds from 2.75% (LI-69) to 7.95% (LI-71), displaying the synergistic effect of the two moieties (CN and pyrrole). Computational analysis disclosed that pyrrole as the auxiliary electron donor (D') in the conjugated bridge can compensate for the lower negative charge in the electron acceptor, which was caused by the CN group as the electron trap, leading to the more efficient electron injection and better photovoltaic performance.

  20. On the multiple imputation variance estimator for control-based and delta-adjusted pattern mixture models.

    Science.gov (United States)

    Tang, Yongqiang

    2017-12-01

    Control-based pattern mixture models (PMM) and delta-adjusted PMMs are commonly used as sensitivity analyses in clinical trials with non-ignorable dropout. These PMMs assume that the statistical behavior of outcomes varies by pattern in the experimental arm in the imputation procedure, but the imputed data are typically analyzed by a standard method such as the primary analysis model. In the multiple imputation (MI) inference, Rubin's variance estimator is generally biased when the imputation and analysis models are uncongenial. One objective of the article is to quantify the bias of Rubin's variance estimator in the control-based and delta-adjusted PMMs for longitudinal continuous outcomes. These PMMs assume the same observed data distribution as the mixed effects model for repeated measures (MMRM). We derive analytic expressions for the MI treatment effect estimator and the associated Rubin's variance in these PMMs and MMRM as functions of the maximum likelihood estimator from the MMRM analysis and the observed proportion of subjects in each dropout pattern when the number of imputations is infinite. The asymptotic bias is generally small or negligible in the delta-adjusted PMM, but can be sizable in the control-based PMM. This indicates that the inference based on Rubin's rule is approximately valid in the delta-adjusted PMM. A simple variance estimator is proposed to ensure asymptotically valid MI inferences in these PMMs, and compared with the bootstrap variance. The proposed method is illustrated by the analysis of an antidepressant trial, and its performance is further evaluated via a simulation study. © 2017, The International Biometric Society.

  1. Modeling and Predicting the EUR/USD Exchange Rate: The Role of Nonlinear Adjustments to Purchasing Power Parity

    OpenAIRE

    Jesús Crespo Cuaresma; Anna Orthofer

    2010-01-01

    Reliable medium-term forecasts are essential for forward-looking monetary policy decisionmaking. Traditionally, predictions of the exchange rate tend to be linked to the equilibrium concept implied by the purchasing power parity (PPP) theory. In particular, the traditional benchmark for exchange rate models is based on a linear adjustment of the exchange rate to the level implied by PPP. In the presence of aggregation effects, transaction costs or uncertainty, however, economic theory predict...

  2. Multiple adjustable vascular clamp prototype: feasibility study on an experimental model of end-to-side microsurgical vascular anastomosis.

    Science.gov (United States)

    Pereira, A; Ichihara, S; Collon, S; Bodin, F; Gay, A; Facca, S; Liverneaux, P

    2014-12-01

    The aim of this study was to establish the feasibility of microsurgical end-to-side vascular anastomosis with a multiclamp adjustable vascular clamp prototype in an inert experimental model. Our method consisted of performing an end-to-side microsurgical anastomosis with 10/0 suture on a 2-mm diameter segment. In group 1, the end-to-side segment was held in place by a double clamp and a single end clamp. In group 2, the segment was held in place with a single multiclamp adjustable clamp. The average time for performing the anastomosis was shorter in group 2. The average number of sutures was the same in both groups. No leak was found and permeability was always positive in both groups. Our results show that performing end-to-side anastomosis with a multiclamp adjustable vascular clamp is feasible in an inert experimental model. Feasibility in a live animal model has to be demonstrated before clinical use. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  3. Spatial downscaling of soil prediction models based on weighted generalized additive models in smallholder farm settings.

    Science.gov (United States)

    Xu, Yiming; Smith, Scot E; Grunwald, Sabine; Abd-Elrahman, Amr; Wani, Suhas P; Nair, Vimala D

    2017-09-11

    Digital soil mapping (DSM) is gaining momentum as a technique to help smallholder farmers secure soil security and food security in developing regions. However, communications of the digital soil mapping information between diverse audiences become problematic due to the inconsistent scale of DSM information. Spatial downscaling can make use of accessible soil information at relatively coarse spatial resolution to provide valuable soil information at relatively fine spatial resolution. The objective of this research was to disaggregate the coarse spatial resolution soil exchangeable potassium (K ex ) and soil total nitrogen (TN) base map into fine spatial resolution soil downscaled map using weighted generalized additive models (GAMs) in two smallholder villages in South India. By incorporating fine spatial resolution spectral indices in the downscaling process, the soil downscaled maps not only conserve the spatial information of coarse spatial resolution soil maps but also depict the spatial details of soil properties at fine spatial resolution. The results of this study demonstrated difference between the fine spatial resolution downscaled maps and fine spatial resolution base maps is smaller than the difference between coarse spatial resolution base maps and fine spatial resolution base maps. The appropriate and economical strategy to promote the DSM technique in smallholder farms is to develop the relatively coarse spatial resolution soil prediction maps or utilize available coarse spatial resolution soil maps at the regional scale and to disaggregate these maps to the fine spatial resolution downscaled soil maps at farm scale.

  4. Risk adjustment model of credit life insurance using a genetic algorithm

    Science.gov (United States)

    Saputra, A.; Sukono; Rusyaman, E.

    2018-03-01

    In managing the risk of credit life insurance, insurance company should acknowledge the character of the risks to predict future losses. Risk characteristics can be learned in a claim distribution model. There are two standard approaches in designing the distribution model of claims over the insurance period i.e, collective risk model and individual risk model. In the collective risk model, the claim arises when risk occurs is called individual claim, accumulation of individual claim during a period of insurance is called an aggregate claim. The aggregate claim model may be formed by large model and a number of individual claims. How the measurement of insurance risk with the premium model approach and whether this approach is appropriate for estimating the potential losses occur in the future. In order to solve the problem Genetic Algorithm with Roulette Wheel Selection is used.

  5. Considering the Epistemic Uncertainties of the Variogram Model in Locating Additional Exploratory Drillholes

    Directory of Open Access Journals (Sweden)

    Saeed Soltani

    2015-06-01

    Full Text Available To enhance the certainty of the grade block model, it is necessary to increase the number of exploratory drillholes and collect more data from the deposit. The inputs of the process of locating these additional drillholes include the variogram model parameters, locations of the samples taken from the initial drillholes, and the geological block model. The uncertainties of these inputs will lead to uncertainties in the optimal locations of additional drillholes. Meanwhile, the locations of the initial data are crisp, but the variogram model parameters and the geological model have uncertainties due to the limitation of the number of initial data. In this paper, effort has been made to consider the effects of variogram uncertainties on the optimal location of additional drillholes using the fuzzy kriging and solve the locating problem with the genetic algorithm (GA optimization method.A bauxite deposit case study has shown the efficiency of the proposed model.

  6. Fitting additive hazards models for case-cohort studies: a multiple imputation approach.

    Science.gov (United States)

    Jung, Jinhyouk; Harel, Ofer; Kang, Sangwook

    2016-07-30

    In this paper, we consider fitting semiparametric additive hazards models for case-cohort studies using a multiple imputation approach. In a case-cohort study, main exposure variables are measured only on some selected subjects, but other covariates are often available for the whole cohort. We consider this as a special case of a missing covariate by design. We propose to employ a popular incomplete data method, multiple imputation, for estimation of the regression parameters in additive hazards models. For imputation models, an imputation modeling procedure based on a rejection sampling is developed. A simple imputation modeling that can naturally be applied to a general missing-at-random situation is also considered and compared with the rejection sampling method via extensive simulation studies. In addition, a misspecification aspect in imputation modeling is investigated. The proposed procedures are illustrated using a cancer data example. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  7. An Adjusted Calculation Model of Reduced Heparin Doses in Cardiopulmonary Bypass Surgery in a Chinese Population.

    Science.gov (United States)

    Zhang, Yufeng; Liu, Kai; Li, Wei; Xue, Qian; Hong, Jiang; Xu, Jibin; Wu, Lihui; Ji, Guangyu; Sheng, Jihong; Wang, Zhinong

    2016-10-01

    To investigate the safety and efficacy of an adjusted regimen of heparin infusion in cardiopulmonary bypass (CPB) surgery in a Chinese population. Prospective, single-center, observational study. University teaching hospital. Patients having cardiac surgery with CPB were selected for this study using the following criteria: 18 to 75 years of age, undergoing first-time cardiac surgery with conventional median sternotomy, aortic clamping time between 40 and 120 minutes, and preoperative routine blood tests showing normal liver, renal, and coagulation functions. The exclusion criteria include salvage cases, a history of coagulopathy in the family, and long-term use of anticoagulation or antiplatelet drugs. Sixty patients were divided randomly into a control group (n = 30) receiving a traditional heparin regimen and an experimental group (n = 30) receiving an adjusted regimen. Activated coagulation time (ACT) was monitored at different time points, ACT>480 seconds was set as the safety threshold of CPB. Heparin doses (initial dose, added dose, and total dose), protamine doses (initial dose, added dose, and total dose), CPB time, aortic clamping time, assisted circulation time, sternal closure time, blood transfusion volume, and drainage volume 24 hours after surgery were recorded. There was no significant difference in achieving target ACT after the initial dose of heparin between the 2 groups; CPB time, aortic clamping time, assisted circulation time, postoperative complication rate, and drainage volume between the 2 groups were not significantly different (p>0.05). However, initial and total dosage of heparin, initial and total dosage of protamine, sternal closure time, and intraoperative blood transfusion volume in the experimental group were significantly lower (pChinese CPB patients, which might reduce the initial and total dosage of heparin and protamine as well as sternal closure time and intraoperative blood transfusion volume. Copyright © 2016 Elsevier Inc

  8. Patterns of Children’s Adrenocortical Reactivity to Interparental Conflict and Associations with Child Adjustment: A Growth Mixture Modeling Approach

    Science.gov (United States)

    Koss, Kalsea J.; George, Melissa R. W.; Davies, Patrick T.; Cicchetti, Dante; Cummings, E. Mark; Sturge-Apple, Melissa L.

    2013-01-01

    Examining children’s physiological functioning is an important direction for understanding the links between interparental conflict and child adjustment. Utilizing growth mixture modeling, the present study examined children’s cortisol reactivity patterns in response to a marital dispute. Analyses revealed three different patterns of cortisol responses, consistent with both a sensitization and an attenuation hypothesis. Child-rearing disagreements and perceived threat were associated with children exhibiting a rising cortisol pattern whereas destructive conflict was related to children displaying a flat pattern. Physiologically rising patterns were also linked with emotional insecurity and internalizing and externalizing behaviors. Results supported a sensitization pattern of responses as maladaptive for children in response to marital conflict with evidence also linking an attenuation pattern with risk. The present study supports children’s adrenocortical functioning as one mechanism through which interparental conflict is related to children’s coping responses and psychological adjustment. PMID:22545835

  9. Research on model of additional forces of ocean conditions in one-dimensional coolant channel

    International Nuclear Information System (INIS)

    Qian Libo; Tian Wenxi; Qiu Suizheng; Su Guanghui; Li Yong; Huang Yanping; Yan Xiao

    2012-01-01

    The effect of different ocean conditions on coolant flow can come down to the differences of additional forces in the momentum equations, thus ocean conditions can be considered by adding the additional forces caused by them to the momentum equations. The model of additional forces of 6 types of typical and relevant coupled ocean conditions is obtained based on the basic momentum equation in the non-inertial reference frame and the one-dimensional coolant channel. (authors)

  10. Estimation of emission adjustments from the application of four-dimensional data assimilation to photochemical air quality modeling

    International Nuclear Information System (INIS)

    Mendoza-Dominguez, A.; Russell, A.G.

    2001-01-01

    Four-dimensional data assimilation applied to photochemical air quality modeling is used to suggest adjustments to the emissions inventory of the Atlanta, Georgia metropolitan area. In this approach, a three-dimensional air quality model, coupled with direct sensitivity analysis, develops spatially and temporally varying concentration and sensitivity fields that account for chemical and physical processing, and receptor analysis is used to adjust source strengths. Proposed changes to domain-wide NO x , volatile organic compounds (VOCs) and CO emissions from anthropogenic sources and for VOC emissions from biogenic sources were estimated, as well as modifications to sources based on their spatial location (urban vs. rural areas). In general, domain-wide anthropogenic VOC emissions were increased approximately two times their base case level to best match observations, domain-wide anthropogenic NO x and biogenic VOC emissions (BEIS2 estimates) remained close to their base case value and domain-wide CO emissions were decreased. Adjustments for anthropogenic NO x emissions increased their level of uncertainty when adjustments were computed for mobile and area sources (or urban and rural sources) separately, due in part to the poor spatial resolution of the observation field of nitrogen-containing species. Estimated changes to CO emissions also suffer from poor spatial resolution of the measurements. Results suggest that rural anthropogenic VOC emissions appear to be severely underpredicted. The FDDA approach was also used to investigate the speciation profiles of VOC emissions, and results warrant revision of these profiles. In general, the results obtained here are consistent with what are viewed as the current deficiencies in emissions inventories as derived by other top-down techniques, such as tunnel studies and analysis of ambient measurements. (Author)

  11. Degree of multicollinearity and variables involved in linear dependence in additive-dominant models

    Directory of Open Access Journals (Sweden)

    Juliana Petrini

    2012-12-01

    Full Text Available The objective of this work was to assess the degree of multicollinearity and to identify the variables involved in linear dependence relations in additive-dominant models. Data of birth weight (n=141,567, yearling weight (n=58,124, and scrotal circumference (n=20,371 of Montana Tropical composite cattle were used. Diagnosis of multicollinearity was based on the variance inflation factor (VIF and on the evaluation of the condition indexes and eigenvalues from the correlation matrix among explanatory variables. The first model studied (RM included the fixed effect of dam age class at calving and the covariates associated to the direct and maternal additive and non-additive effects. The second model (R included all the effects of the RM model except the maternal additive effects. Multicollinearity was detected in both models for all traits considered, with VIF values of 1.03 - 70.20 for RM and 1.03 - 60.70 for R. Collinearity increased with the increase of variables in the model and the decrease in the number of observations, and it was classified as weak, with condition index values between 10.00 and 26.77. In general, the variables associated with additive and non-additive effects were involved in multicollinearity, partially due to the natural connection between these covariables as fractions of the biological types in breed composition.

  12. Opportunities for Improving Army Modeling and Simulation Development: Making Fundamental Adjustments and Borrowing Commercial Business Practices

    National Research Council Canada - National Science Library

    Lee, John

    2000-01-01

    .... This paper briefly explores project management principles, leadership theory, and commercial business practices, suggesting improvements to the Army's modeling and simulation development process...

  13. Dynamic Modeling of Adjustable-Speed Pumped Storage Hydropower Plant: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Singh, M.; Gevorgian, V.; Mohanpurkar, M.; Havsapian, R.; Koritarov, V.

    2015-04-06

    Hydropower is the largest producer of renewable energy in the U.S. More than 60% of the total renewable generation comes from hydropower. There is also approximately 22 GW of pumped storage hydropower (PSH). Conventional PSH uses a synchronous generator, and thus the rotational speed is constant at synchronous speed. This work details a hydrodynamic model and generator/power converter dynamic model. The optimization of the hydrodynamic model is executed by the hydro-turbine controller, and the electrical output real/reactive power is controlled by the power converter. All essential controllers to perform grid-interface functions and provide ancillary services are included in the model.

  14. The method ADAMONT v1.0 for statistical adjustment of climate projections applicable to energy balance land surface models

    Directory of Open Access Journals (Sweden)

    D. Verfaillie

    2017-11-01

    Full Text Available We introduce the method ADAMONT v1.0 to adjust and disaggregate daily climate projections from a regional climate model (RCM using an observational dataset at hourly time resolution. The method uses a refined quantile mapping approach for statistical adjustment and an analogous method for sub-daily disaggregation. The method ultimately produces adjusted hourly time series of temperature, precipitation, wind speed, humidity, and short- and longwave radiation, which can in turn be used to force any energy balance land surface model. While the method is generic and can be employed for any appropriate observation time series, here we focus on the description and evaluation of the method in the French mountainous regions. The observational dataset used here is the SAFRAN meteorological reanalysis, which covers the entire French Alps split into 23 massifs, within which meteorological conditions are provided for several 300 m elevation bands. In order to evaluate the skills of the method itself, it is applied to the ALADIN-Climate v5 RCM using the ERA-Interim reanalysis as boundary conditions, for the time period from 1980 to 2010. Results of the ADAMONT method are compared to the SAFRAN reanalysis itself. Various evaluation criteria are used for temperature and precipitation but also snow depth, which is computed by the SURFEX/ISBA-Crocus model using the meteorological driving data from either the adjusted RCM data or the SAFRAN reanalysis itself. The evaluation addresses in particular the time transferability of the method (using various learning/application time periods, the impact of the RCM grid point selection procedure for each massif/altitude band configuration, and the intervariable consistency of the adjusted meteorological data generated by the method. Results show that the performance of the method is satisfactory, with similar or even better evaluation metrics than alternative methods. However, results for air temperature are generally

  15. The method ADAMONT v1.0 for statistical adjustment of climate projections applicable to energy balance land surface models

    Science.gov (United States)

    Verfaillie, Deborah; Déqué, Michel; Morin, Samuel; Lafaysse, Matthieu

    2017-11-01

    We introduce the method ADAMONT v1.0 to adjust and disaggregate daily climate projections from a regional climate model (RCM) using an observational dataset at hourly time resolution. The method uses a refined quantile mapping approach for statistical adjustment and an analogous method for sub-daily disaggregation. The method ultimately produces adjusted hourly time series of temperature, precipitation, wind speed, humidity, and short- and longwave radiation, which can in turn be used to force any energy balance land surface model. While the method is generic and can be employed for any appropriate observation time series, here we focus on the description and evaluation of the method in the French mountainous regions. The observational dataset used here is the SAFRAN meteorological reanalysis, which covers the entire French Alps split into 23 massifs, within which meteorological conditions are provided for several 300 m elevation bands. In order to evaluate the skills of the method itself, it is applied to the ALADIN-Climate v5 RCM using the ERA-Interim reanalysis as boundary conditions, for the time period from 1980 to 2010. Results of the ADAMONT method are compared to the SAFRAN reanalysis itself. Various evaluation criteria are used for temperature and precipitation but also snow depth, which is computed by the SURFEX/ISBA-Crocus model using the meteorological driving data from either the adjusted RCM data or the SAFRAN reanalysis itself. The evaluation addresses in particular the time transferability of the method (using various learning/application time periods), the impact of the RCM grid point selection procedure for each massif/altitude band configuration, and the intervariable consistency of the adjusted meteorological data generated by the method. Results show that the performance of the method is satisfactory, with similar or even better evaluation metrics than alternative methods. However, results for air temperature are generally better than for

  16. The chaos and control of a food chain model supplying additional food to top-predator

    International Nuclear Information System (INIS)

    Sahoo, Banshidhar; Poria, Swarup

    2014-01-01

    Highlights: • We propose a chaotic food chain model supplying additional food to top-predator. • Local and global stability conditions are derived in presence of additional food. • Chaos is controlled only by increasing quantity of additional food. • System enters into periodic region and depicts Hopf bifurcations supplying additional food. • This an application of non-chemical methods for controlling chaos. -- Abstract: The control and management of chaotic population is one of the main objectives for constructing mathematical model in ecology today. In this paper, we apply a technique of controlling chaotic predator–prey population dynamics by supplying additional food to top-predator. We formulate a three species predator–prey model supplying additional food to top-predator. Existence conditions and local stability criteria of equilibrium points are determined analytically. Persistence conditions for the system are derived. Global stability conditions of interior equilibrium point is calculated. Theoretical results are verified through numerical simulations. Phase diagram is presented for various quality and quantity of additional food. One parameter bifurcation analysis is done with respect to quality and quantity of additional food separately keeping one of them fixed. Using MATCONT package, we derive the bifurcation scenarios when both the parameters quality and quantity of additional food vary together. We predict the existence of Hopf point (H), limit point (LP) and branch point (BP) in the model for suitable supply of additional food. We have computed the regions of different dynamical behaviour in the quantity–quality parametric plane. From our study we conclude that chaotic population dynamics of predator prey system can be controlled to obtain regular population dynamics only by supplying additional food to top predator. This study is aimed to introduce a new non-chemical chaos control mechanism in a predator–prey system with the

  17. Experts' adjustment to model-based forecasts: Does the forecast horizon matter?

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); R. Legerstee (Rianne)

    2007-01-01

    textabstractExperts may have domain-specific knowledge that is not included in a statistical model and that can improve forecasts. While one-step-ahead forecasts address the conditional mean of the variable, model-based forecasts for longer horizons have a tendency to convert to the unconditional

  18. Covariate Measurement Error Adjustment for Multilevel Models with Application to Educational Data

    Science.gov (United States)

    Battauz, Michela; Bellio, Ruggero; Gori, Enrico

    2011-01-01

    This article proposes a multilevel model for the assessment of school effectiveness where the intake achievement is a predictor and the response variable is the achievement in the subsequent periods. The achievement is a latent variable that can be estimated on the basis of an item response theory model and hence subject to measurement error.…

  19. Glacial isostatic adjustment model with composite 3-D Earth rheology for Fennoscandia

    NARCIS (Netherlands)

    van der Wal, W.; Barnhoorn, A.; Stocchi, P.; Gradmann, S.; Wu, P.; Drury, M.; Vermeersen, B.

    2013-01-01

    We find that sea level data can be explained with our ice model and with information on mantle rheology from laboratory experiments, heatflow and seismology and a pure olivine rheology above 400 km. Moreover, laterally heterogeneous models provide a significantly better fit to relative sea level

  20. Utility of a single adjusting compartment: a novel methodology for whole body physiologically-based pharmacokinetic modelling

    Science.gov (United States)

    Ando, Hirotaka; Izawa, Shigeru; Hori, Wataru; Nakagawa, Ippei

    2008-01-01

    Background There are various methods for predicting human pharmacokinetics. Among these, a whole body physiologically-based pharmacokinetic (WBPBPK) model is useful because it gives a mechanistic description. However, WBPBPK models cannot predict human pharmacokinetics with enough precision. This study was conducted to elucidate the primary reason for poor predictions by WBPBPK models, and to enable better predictions to be made without reliance on complex concepts. Methods The primary reasons for poor predictions of human pharmacokinetics were investigated using a generic WBPBPK model that incorporated a single adjusting compartment (SAC), a virtual organ compartment with physiological parameters that can be adjusted arbitrarily. The blood flow rate, organ volume, and the steady state tissue-plasma partition coefficient of a SAC were calculated to fit simulated to observed pharmacokinetics in the rat. The adjusted SAC parameters were fixed and scaled up to the human using a newly developed equation. Using the scaled-up SAC parameters, human pharmacokinetics were simulated and each pharmacokinetic parameter was calculated. These simulated parameters were compared to the observed data. Simulations were performed to confirm the relationship between the precision of prediction and the number of tissue compartments, including a SAC. Results Increasing the number of tissue compartments led to an improvement of the average-fold error (AFE) of total body clearances (CLtot) and half-lives (T1/2) calculated from the simulated human blood concentrations of 14 drugs. The presence of a SAC also improved the AFE values of a ten-organ model from 6.74 to 1.56 in CLtot, and from 4.74 to 1.48 in T1/2. Moreover, the within-2-fold errors were improved in all models; incorporating a SAC gave results from 0 to 79% in CLtot, and from 14 to 93% in T1/2 of the ten-organ model. Conclusion By using a SAC in this study, we were able to show that poor prediction resulted mainly from such

  1. Chiropractic Adjustment

    Science.gov (United States)

    ... Results Chiropractic adjustment can be effective in treating low back pain, although much of the research done shows only a modest benefit — similar to the results of more conventional treatments. Some studies suggest that spinal manipulation also may ...

  2. Chiropractic Adjustment

    Science.gov (United States)

    ... How you prepare No special preparation is required before a chiropractic adjustment. Chiropractic treatment may require a series of visits to your chiropractor. Ask your care provider about the frequency of visits and be ...

  3. A joint logistic regression and covariate-adjusted continuous-time Markov chain model.

    Science.gov (United States)

    Rubin, Maria Laura; Chan, Wenyaw; Yamal, Jose-Miguel; Robertson, Claudia Sue

    2017-12-10

    The use of longitudinal measurements to predict a categorical outcome is an increasingly common goal in research studies. Joint models are commonly used to describe two or more models simultaneously by considering the correlated nature of their outcomes and the random error present in the longitudinal measurements. However, there is limited research on joint models with longitudinal predictors and categorical cross-sectional outcomes. Perhaps the most challenging task is how to model the longitudinal predictor process such that it represents the true biological mechanism that dictates the association with the categorical response. We propose a joint logistic regression and Markov chain model to describe a binary cross-sectional response, where the unobserved transition rates of a two-state continuous-time Markov chain are included as covariates. We use the method of maximum likelihood to estimate the parameters of our model. In a simulation study, coverage probabilities of about 95%, standard deviations close to standard errors, and low biases for the parameter values show that our estimation method is adequate. We apply the proposed joint model to a dataset of patients with traumatic brain injury to describe and predict a 6-month outcome based on physiological data collected post-injury and admission characteristics. Our analysis indicates that the information provided by physiological changes over time may help improve prediction of long-term functional status of these severely ill subjects. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Linear identification and model adjustment of a PEM fuel cell stack

    Energy Technology Data Exchange (ETDEWEB)

    Kunusch, C.; Puleston, P.F.; More, J.J. [LEICI, Departamento de Electrotecnia, Universidad Nacional de La Plata, calle 1 esq. 47 s/n, 1900 La Plata (Argentina); Consejo de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Husar, A. [Institut de Robotica i Informatica Industrial (CSIC-UPC), c/ Llorens i Artigas 4-6, 08028 Barcelona (Spain); Mayosky, M.A. [LEICI, Departamento de Electrotecnia, Universidad Nacional de La Plata, calle 1 esq. 47 s/n, 1900 La Plata (Argentina); Comision de Investigaciones Cientificas (CIC), Provincia de Buenos Aires (Argentina)

    2008-07-15

    In the context of fuel cell stack control a mayor challenge is modeling the interdependence of various complex subsystem dynamics. In many cases, the states interaction is usually modeled through several look-up tables, decision blocks and piecewise continuous functions. Many internal variables are inaccessible for measurement and cannot be used in control algorithms. To make significant contributions in this area, it is necessary to develop reliable models for control and design purposes. In this paper, a linear model based on experimental identification of a 7-cell stack was developed. The procedure followed to obtain a linear model of the system consisted in performing spectroscopy tests of four different single-input single-output subsystems. The considered inputs for the tests were the stack current and the cathode oxygen flow rate, while the measured outputs were the stack voltage and the cathode total pressure. The resulting model can be used either for model-based control design or for on-line analysis and errors detection. (author)

  5. Utilization of sulfate additives in biomass combustion: fundamental and modeling aspects

    DEFF Research Database (Denmark)

    Wu, Hao; Jespersen, Jacob Boll; Grell, Morten Nedergaard

    2013-01-01

    Sulfates, such as ammonium sulfate, aluminum sulfate and ferric sulfate, are effective additives for converting the alkali chlorides released from biomass combustion to the less harmful alkali sulfates. Optimization of the use of these additives requires knowledge on their decomposition rate...... was combined with a detailed gas-phase kinetic model of KCl sulfation and a model of K2SO4 condensation to simulate the sulfation of KCl by ferric sulfate addition. The simulation results showed good agreements with the experiments conducted in a biomass grate-firing combustor, where ferric sulfate...... and elemental sulfur were used as additives. The results indicated that the SO3 released from ferric sulfate decomposition was the main contributor to KCl sulfation and that the effectiveness of ferric sulfate addition was sensitive to the applied temperature conditions. Comparison of the effectiveness...

  6. Modeling the Use of Sulfate Additives for Potassium Chloride Destruction in Biomass Combustion

    DEFF Research Database (Denmark)

    Wu, Hao; Pedersen, Morten Nedergaard; Jespersen, Jacob Boll

    2014-01-01

    Potassium chloride, KCl, formed from biomass combustion may lead to ash deposition and corrosion problems in boilers. Sulfates are effective additives for converting KCl to the less harmful K2SO4 and HCl. In the present study, the rate constants for decomposition of ammonium sulfate and aluminum......-dependent distribution of SO2 and SO3 from ammonium sulfate decomposition. On the basis of these data as well as earlier results, a detailed chemical kinetic model for sulfation of KCl by a range of sulfate additives was established. Modeling results were compared to biomass combustion experiments in a bubbling...... fluidized-bed reactor using ammonium sulfate, aluminum sulfate, and ferric sulfate as additives. The simulation results for ammonium sulfate and ferric sulfate addition compared favorably to the experiments. The predictions for aluminum sulfate addition were only partly in agreement with the experimental...

  7. Incorporating additional tree and environmental variables in a lodgepole pine stem profile model

    Science.gov (United States)

    John C. Byrne

    1993-01-01

    A new variable-form segmented stem profile model is developed for lodgepole pine (Pinus contorta) trees from the northern Rocky Mountains of the United States. I improved estimates of stem diameter by predicting two of the model coefficients with linear equations using a measure of tree form, defined as a ratio of dbh and total height. Additional improvements were...

  8. Testing a Gender Additive Model: The Role of Body Image in Adolescent Depression

    Science.gov (United States)

    Bearman, Sarah Kate; Stice, Eric

    2008-01-01

    Despite consistent evidence that adolescent girls are at greater risk of developing depression than adolescent boys, risk factor models that account for this difference have been elusive. The objective of this research was to examine risk factors proposed by the "gender additive" model of depression that attempts to partially explain the increased…

  9. Real time adjustment of slow changing flow components in distributed urban runoff models

    DEFF Research Database (Denmark)

    Borup, Morten; Grum, M.; Mikkelsen, Peter Steen

    2011-01-01

    In many urban runoff systems infiltrating water contributes with a substantial part of the total inflow and therefore most urban runoff modelling packages include hydrological models for simulating the infiltrating inflow. This paper presents a method for deterministic updating of the hydrological....... This information is then used to update the states of the hydrological model. The method is demonstrated on the 20 km2 Danish urban catchment of Ballerup, which has substantial amount of infiltration inflow after succeeding rain events, for a very rainy period of 17 days in August 2010. The results show big...

  10. Elasto-plastic hardening models adjustment to ferritic, austenitic and austenoferritic Rebar

    International Nuclear Information System (INIS)

    Hortigóna, B.; Gallardo, J.M.; Nieto-García, E.J.; López, J.A.

    2017-01-01

    The elastoplastic behaviour of steel used for structural member fabrication has received attention to facilitate a mechanical-resistant design. New Zealand and South African standards have adopted various theoretical approaches to describe such behaviour in stainless steels. With respect to the building industry, describing the tensile behaviour of steel rebar used to produce reinforced concrete structures is of interest. Differences compared with the homogenous material described in the above mentioned standards and related literatures are discussed in this paper. Specifically, the presence of ribs and the TEMPCORE® technology used to produce carbon steel rebar may alter the elastoplastic model. Carbon steel rebar is shown to fit a Hollomon model giving hardening exponent values on the order of 0.17. Austenitic stainless steel rebar behaviour is better described using a modified Rasmussen model with a free fitted exponent of 6. Duplex stainless steel shows a poor fit to any previous model. [es

  11. Modeling and simulation of M/M/c queuing pharmacy system with adjustable parameters

    Science.gov (United States)

    Rashida, A. R.; Fadzli, Mohammad; Ibrahim, Safwati; Goh, Siti Rohana

    2016-02-01

    This paper studies a discrete event simulation (DES) as a computer based modelling that imitates a real system of pharmacy unit. M/M/c queuing theo is used to model and analyse the characteristic of queuing system at the pharmacy unit of Hospital Tuanku Fauziah, Kangar in Perlis, Malaysia. The input of this model is based on statistical data collected for 20 working days in June 2014. Currently, patient waiting time of pharmacy unit is more than 15 minutes. The actual operation of the pharmacy unit is a mixed queuing server with M/M/2 queuing model where the pharmacist is referred as the server parameters. DES approach and ProModel simulation software is used to simulate the queuing model and to propose the improvement for queuing system at this pharmacy system. Waiting time for each server is analysed and found out that Counter 3 and 4 has the highest waiting time which is 16.98 and 16.73 minutes. Three scenarios; M/M/3, M/M/4 and M/M/5 are simulated and waiting time for actual queuing model and experimental queuing model are compared. The simulation results show that by adding the server (pharmacist), it will reduce patient waiting time to a reasonable improvement. Almost 50% average patient waiting time is reduced when one pharmacist is added to the counter. However, it is not necessary to fully utilize all counters because eventhough M/M/4 and M/M/5 produced more reduction in patient waiting time, but it is ineffective since Counter 5 is rarely used.

  12. Model-based Adjustment of Droplet Characteristic for 3D Electronic Printing

    Directory of Open Access Journals (Sweden)

    Lin Na

    2017-01-01

    Full Text Available The major challenge in 3D electronic printing is the print resolution and accuracy. In this paper, a typical mode - lumped element modeling method (LEM - is adopted to simulate the droplet jetting characteristic. This modeling method can quickly get the droplet velocity and volume with a high accuracy. Experimental results show that LEM has a simpler structure with the sufficient simulation and prediction accuracy.

  13. The combined geodetic network adjusted on the reference ellipsoid – a comparison of three functional models for GNSS observations

    Directory of Open Access Journals (Sweden)

    Kadaj Roman

    2016-12-01

    Full Text Available The adjustment problem of the so-called combined (hybrid, integrated network created with GNSS vectors and terrestrial observations has been the subject of many theoretical and applied works. The network adjustment in various mathematical spaces was considered: in the Cartesian geocentric system on a reference ellipsoid and on a mapping plane. For practical reasons, it often takes a geodetic coordinate system associated with the reference ellipsoid. In this case, the Cartesian GNSS vectors are converted, for example, into geodesic parameters (azimuth and length on the ellipsoid, but the simple form of converted pseudo-observations are the direct differences of the geodetic coordinates. Unfortunately, such an approach may be essentially distorted by a systematic error resulting from the position error of the GNSS vector, before its projection on the ellipsoid surface. In this paper, an analysis of the impact of this error on the determined measures of geometric ellipsoid elements, including the differences of geodetic coordinates or geodesic parameters is presented. Assuming that the adjustment of a combined network on the ellipsoid shows that the optimal functional approach in relation to the satellite observation, is to create the observational equations directly for the original GNSS Cartesian vector components, writing them directly as a function of the geodetic coordinates (in numerical applications, we use the linearized forms of observational equations with explicitly specified coefficients. While retaining the original character of the Cartesian vector, one avoids any systematic errors that may occur in the conversion of the original GNSS vectors to ellipsoid elements, for example the vector of the geodesic parameters. The problem is theoretically developed and numerically tested. An example of the adjustment of a subnet loaded from the database of reference stations of the ASG-EUPOS system was considered for the preferred functional

  14. Between and beyond additivity and non-additivity : the statistical modelling of genotype by environment interaction in plant breeding

    NARCIS (Netherlands)

    Eeuwijk, van F.A.

    1996-01-01

    In plant breeding it is a common observation to see genotypes react differently to environmental changes. This phenomenon is called genotype by environment interaction. Many statistical approaches for analysing genotype by environment interaction rely heavily on the analysis of variance model.

  15. Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

    Directory of Open Access Journals (Sweden)

    Natalya Pya

    2016-02-01

    Full Text Available Background: Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height (dbh can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter (h-d models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods: We develop unconstrained generalized additive models (GAM and shape constrained generalized additive models (SCAM for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results: Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand. The definition of constraints leads only to marginal or minor decline in the model statistics like AIC. An observed structured spatial trend in tree height is modelled via 2-dimensional surface

  16. Detection of superior genotype of fatty acid synthase in Korean native cattle by an environment-adjusted statistical model

    Directory of Open Access Journals (Sweden)

    Jea-Young Lee

    2017-06-01

    Full Text Available Objective This study examines the genetic factors influencing the phenotypes (four economic traits:oleic acid [C18:1], monounsaturated fatty acids, carcass weight, and marbling score of Hanwoo. Methods To enhance the accuracy of the genetic analysis, the study proposes a new statistical model that excludes environmental factors. A statistically adjusted, analysis of covariance model of environmental and genetic factors was developed, and estimated environmental effects (covariate effects of age and effects of calving farms were excluded from the model. Results The accuracy was compared before and after adjustment. The accuracy of the best single nucleotide polymorphism (SNP in C18:1 increased from 60.16% to 74.26%, and that of the two-factor interaction increased from 58.69% to 87.19%. Also, superior SNPs and SNP interactions were identified using the multifactor dimensionality reduction method in Table 1 to 4. Finally, high- and low-risk genotypes were compared based on their mean scores for each trait. Conclusion The proposed method significantly improved the analysis accuracy and identified superior gene-gene interactions and genotypes for each of the four economic traits of Hanwoo.

  17. Experimental Robot Model Adjustments Based on Force-Torque Sensor Information.

    Science.gov (United States)

    Martinez, Santiago; Garcia-Haro, Juan Miguel; Victores, Juan G; Jardon, Alberto; Balaguer, Carlos

    2018-03-11

    The computational complexity of humanoid robot balance control is reduced through the application of simplified kinematics and dynamics models. However, these simplifications lead to the introduction of errors that add to other inherent electro-mechanic inaccuracies and affect the robotic system. Linear control systems deal with these inaccuracies if they operate around a specific working point but are less precise if they do not. This work presents a model improvement based on the Linear Inverted Pendulum Model (LIPM) to be applied in a non-linear control system. The aim is to minimize the control error and reduce robot oscillations for multiple working points. The new model, named the Dynamic LIPM (DLIPM), is used to plan the robot behavior with respect to changes in the balance status denoted by the zero moment point (ZMP). Thanks to the use of information from force-torque sensors, an experimental procedure has been applied to characterize the inaccuracies and introduce them into the new model. The experiments consist of balance perturbations similar to those of push-recovery trials, in which step-shaped ZMP variations are produced. The results show that the responses of the robot with respect to balance perturbations are more precise and the mechanical oscillations are reduced without comprising robot dynamics.

  18. A phased transition to a market adjustment of the pseudo model of Russian economy

    Directory of Open Access Journals (Sweden)

    N. Komkov

    2015-01-01

    Full Text Available We consider a phased reform of the economic model of Russia. In less than one century, Russia was in the extreme conditions of the model economy: the developed socialism (1917 and perfect capitalism (1991. Within each of them there was the instability of socio-economic development: economic recovery alternated recession and huge reserves of natural resources and to develop and use of land is not always effective. At each extremity of the selection was based largely on the current political aims and attitudes formed by various social groups. Russia achieved the economic situation and the prevailing socio-economic model of many subjected to fair criticism. To improve it proposes a phased approach to reform, when the main focus is on "how" to move to a new state. The approach is based on consideration of the scenario approach to the reform of the basic components of the economic model that involves the formation of a better scenario analysis and evaluation of the expert community the degree of closeness of planned versions of the model national development objectives of the country.

  19. Adjustment and Characterization of an Original Model of Chronic Ischemic Heart Failure in Pig

    Directory of Open Access Journals (Sweden)

    Laurent Barandon

    2010-01-01

    Full Text Available We present and characterize an original experimental model to create a chronic ischemic heart failure in pig. Two ameroid constrictors were placed around the LAD and the circumflex artery. Two months after surgery, pigs presented a poor LV function associated with a severe mitral valve insufficiency. Echocardiography analysis showed substantial anomalies in radial and circumferential deformations, both on the anterior and lateral surface of the heart. These anomalies in function were coupled with anomalies of perfusion observed in echocardiography after injection of contrast medium. No demonstration of myocardial infarction was observed with histological analysis. Our findings suggest that we were able to create and to stabilize a chronic ischemic heart failure model in the pig. This model represents a useful tool for the development of new medical or surgical treatment in this field.

  20. A statistical adjustment approach for climate projections of snow conditions in mountain regions using energy balance land surface models

    Science.gov (United States)

    Verfaillie, Deborah; Déqué, Michel; Morin, Samuel; Lafaysse, Matthieu

    2017-04-01

    Projections of future climate change have been increasingly called for lately, as the reality of climate change has been gradually accepted and societies and governments have started to plan upcoming mitigation and adaptation policies. In mountain regions such as the Alps or the Pyrenees, where winter tourism and hydropower production are large contributors to the regional revenue, particular attention is brought to current and future snow availability. The question of the vulnerability of mountain ecosystems as well as the occurrence of climate-related hazards such as avalanches and debris-flows is also under consideration. In order to generate projections of snow conditions, however, downscaling global climate models (GCMs) by using regional climate models (RCMs) is not sufficient to capture the fine-scale processes and thresholds at play. In particular, the altitudinal resolution matters, since the phase of precipitation is mainly controlled by the temperature which is altitude-dependent. Simulations from GCMs and RCMs moreover suffer from biases compared to local observations, due to their rather coarse spatial and altitudinal resolution, and often provide outputs at too coarse time resolution to drive impact models. RCM simulations must therefore be adjusted using empirical-statistical downscaling and error correction methods, before they can be used to drive specific models such as energy balance land surface models. In this study, time series of hourly temperature, precipitation, wind speed, humidity, and short- and longwave radiation were generated over the Pyrenees and the French Alps for the period 1950-2100, by using a new approach (named ADAMONT for ADjustment of RCM outputs to MOuNTain regions) based on quantile mapping applied to daily data, followed by time disaggregation accounting for weather patterns selection. We first introduce a thorough evaluation of the method using using model runs from the ALADIN RCM driven by a global reanalysis over the

  1. Citizens' Perceptions of Flood Hazard Adjustments: An Application of the Protective Action Decision Model

    Science.gov (United States)

    Terpstra, Teun; Lindell, Michael K.

    2013-01-01

    Although research indicates that adoption of flood preparations among Europeans is low, only a few studies have attempted to explain citizens' preparedness behavior. This article applies the Protective Action Decision Model (PADM) to explain flood preparedness intentions in the Netherlands. Survey data ("N" = 1,115) showed that…

  2. CFD modeling of a prismatic spouted bed with two adjustable gas inlets

    NARCIS (Netherlands)

    Gryczka, Oliver; Heinrich, Stefan; Deen, N.G.; van Sint Annaland, M.; Kuipers, J.A.M.; Mörl, Lothar

    2009-01-01

    Since the invention of the spouted bed technology by Mathur and Gishler (1955), different kinds of apparatus design were developed and a huge number of applications in nearly all branches of industry have emerged. Modeling of spouted beds by means of modern simulation tools, like discrete particle

  3. The linear quadratic adjustment cost model and the demand for labour

    DEFF Research Database (Denmark)

    Engsted, Tom; Haldrup, Niels

    1994-01-01

    Der udvikles en ny metode til estimation og test af den lineære kvadratiske tilpasningsomkostningsmodel når de underliggende tidsserier er ikke-stationære, og metoden anvendes til modellering af arbejdskraftefterspørgslen i danske industrisektorer....

  4. An improved canopy wind model for predicting wind adjustment factors and wildland fire behavior

    Science.gov (United States)

    W. J. Massman; J. M. Forthofer; M. A. Finney

    2017-01-01

    The ability to rapidly estimate wind speed beneath a forest canopy or near the ground surface in any vegetation is critical to practical wildland fire behavior models. The common metric of this wind speed is the "mid-flame" wind speed, UMF. However, the existing approach for estimating UMF has some significant shortcomings. These include the assumptions that...

  5. Structured Additive Regression Models: An R Interface to BayesX

    Directory of Open Access Journals (Sweden)

    Nikolaus Umlauf

    2015-02-01

    Full Text Available Structured additive regression (STAR models provide a flexible framework for model- ing possible nonlinear effects of covariates: They contain the well established frameworks of generalized linear models and generalized additive models as special cases but also allow a wider class of effects, e.g., for geographical or spatio-temporal data, allowing for specification of complex and realistic models. BayesX is standalone software package providing software for fitting general class of STAR models. Based on a comprehensive open-source regression toolbox written in C++, BayesX uses Bayesian inference for estimating STAR models based on Markov chain Monte Carlo simulation techniques, a mixed model representation of STAR models, or stepwise regression techniques combining penalized least squares estimation with model selection. BayesX not only covers models for responses from univariate exponential families, but also models from less-standard regression situations such as models for multi-categorical responses with either ordered or unordered categories, continuous time survival data, or continuous time multi-state models. This paper presents a new fully interactive R interface to BayesX: the R package R2BayesX. With the new package, STAR models can be conveniently specified using Rs formula language (with some extended terms, fitted using the BayesX binary, represented in R with objects of suitable classes, and finally printed/summarized/plotted. This makes BayesX much more accessible to users familiar with R and adds extensive graphics capabilities for visualizing fitted STAR models. Furthermore, R2BayesX complements the already impressive capabilities for semiparametric regression in R by a comprehensive toolbox comprising in particular more complex response types and alternative inferential procedures such as simulation-based Bayesian inference.

  6. The regulatory network adjusting light-harvesting in the model green alga Chlamydomonas reinhardtii

    OpenAIRE

    Berger, Hanna

    2015-01-01

    In photosynthetic organisms, control of light-harvesting is a key component of acclimation mechanisms that optimize photon conversion efficiencies. In this thesis, the interrelation of short- and long-term regulation of light-harvesting at photosystem II (PSII) was analyzed in the green alga Chlamydomonas reinhardtii. This model organism is able to gain carbon and energy through photosynthetic carbon dioxide fixation as well as heterotrophic feeding. A lowered inorganic or increased organic c...

  7. Adjusting weather radar data to rain gauge measurements with data-driven models

    Science.gov (United States)

    Teschl, Reinhard; Randeu, Walter; Teschl, Franz

    2010-05-01

    Weather radar networks provide data with good spatial coverage and temporal resolution. Hence they are able to describe the variability of precipitation. Typical radar stations determine the rain rate for every square kilometre and make a full volume scan within about 5 minutes. A weakness however, is their often poor metering precision limiting the applicability of the radar for hydrological purposes. In contrast to rain gauges, which measure precipitation directly on the ground, the radar determines the reflectivity aloft and remote. Due to this principle, several sources of possible errors occur. Therefore improving the radar estimates of rainfall is still a vital topic in radar meteorology and hydrology. This paper presents data-driven approaches to improve radar estimates of rainfall by mapping radar reflectivity measurements Z to rain gauge data R. The analysis encompasses several input configurations and data-driven models. Reflectivity measurements at a constant altitude and the vertical profiles of reflectivity above a rain gauge are used as input parameters. The applied models are Artificial Neural Network (ANN), Model Tree (MT), and IBk a k-nearest-neighbour classifier. The relationship found between the data of a rain gauge and the reflectivity measurements is subsequently applied to another site with comparable terrain. Based on this independent dataset the performance of the data-driven models in the various input configurations is evaluated. For this study, rain gauge and radar data from the province of Styria, Austria, were available. The data sets extend over a two-year period (2001 and 2002). The available rain gauges use the tipping bucket principle with a resolution of 0.1 mm. Reflectivity measurements are obtained from the Doppler weather radar station on Mt. Zirbitzkogel (by courtesy of AustroControl GmbH). The designated radar is a high-resolution C-band weather-radar situated at an altitude of 2372 m above mean sea level. The data

  8. Estimation of direct effects for survival data by using the Aalen additive hazards model

    DEFF Research Database (Denmark)

    Martinussen, Torben; Vansteelandt, Stijn; Gerster, Mette

    2011-01-01

    Aalen's additive regression for the event time, given exposure, intermediate variable and confounders. The second stage involves applying Aalen's additive model, given the exposure alone, to a modified stochastic process (i.e. a modification of the observed counting process based on the first......We extend the definition of the controlled direct effect of a point exposure on a survival outcome, other than through some given, time-fixed intermediate variable, to the additive hazard scale. We propose two-stage estimators for this effect when the exposure is dichotomous and randomly assigned...

  9. Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review

    Science.gov (United States)

    Rosso, Stefano; Meneghello, Roberto; Concheri, Gianmaria

    2018-01-01

    Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed. PMID:29487626

  10. Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review.

    Science.gov (United States)

    Savio, Gianpaolo; Rosso, Stefano; Meneghello, Roberto; Concheri, Gianmaria

    2018-01-01

    Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed.

  11. A Generic Model for Relative Adjustment Between Optical Sensors Using Rigorous Orbit Mechanics

    Directory of Open Access Journals (Sweden)

    B. Islam

    2008-06-01

    Full Text Available The classical calibration or space resection is the fundamental task in photogrammetry. The lack of sufficient knowledge of interior and exterior orientation parameters lead to unreliable results in the photogrammetric process. One of the earliest in approaches using in photogrammetry was the plumb line calibration method. This method is suitable to recover the radial and decentering lens distortion coefficients, while the remaining interior(focal length and principal point coordinates and exterior orientation parameters have to be determined by a complimentary method. As the lens distortion remains very less it not considered as the interior orientation parameters, in the present rigorous sensor model. There are several other available methods based on the photogrammetric collinearity equations, which consider the determination of exterior orientation parameters, with no mention to the simultaneous determination of inner orientation parameters. Normal space resection methods solve the problem using control points, whose coordinates are known both in image and object reference systems. The non-linearity of the model and the problems, in point location in digital images and identifying the maximum GPS measured control points are the main drawbacks of the classical approaches. This paper addresses mathematical model based on the fundamental assumption of collineariy of three points of two Along-Track Stereo imagery sensors and independent object point. Assuming this condition it is possible to extract the exterior orientation (EO parameters for a long strip and single image together, without and with using the control points. Moreover, after extracting the EO parameters the accuracy for satellite data products are compared in with using single and with no control points.

  12. Models of quality-adjusted life years when health varies over time

    DEFF Research Database (Denmark)

    Hansen, Kristian Schultz; Østerdal, Lars Peter Raahave

    2006-01-01

    time tradeoff (TTO) and standard gamble (SG) scores. We investigate deterministic and probabilistic models and consider five different families of discounting functions in all. The second part of the paper discusses four issues recurrently debated in the literature. This discussion includes questioning...... the SG method as the gold standard for estimation of the health state index, reexamining the role of the constantproportional tradeoff condition, revisiting the problem of double discounting of QALYs, and suggesting that it is not a matter of choosing between TTO and SG procedures as the combination...

  13. Models of Quality-Adjusted Life Years when Health varies over Time: Survey and Analysis

    DEFF Research Database (Denmark)

    Hansen, Kristian Schultz; Østerdal, Lars Peter

    2006-01-01

    time trade-off (TTO) and standard gamble (SG) scores. We investigate deterministic and probabilistic models and consider five different families of discounting functions in all. This discussion includes questioning the SG method as the gold standard of the health state index, re-examining the role...... of the constant-proportional trade-off condition, revisiting the problem of double discounting of QALYs, and suggesting that it is not a matter of choosing between TTO and SG procedures as the combination of these two can be used to disentangle risk aversion from discounting. We find that caution must be taken...

  14. Estimation of additive and dominance variance for reproductive traits from different models in Duroc purebred

    Directory of Open Access Journals (Sweden)

    Talerngsak Angkuraseranee

    2010-05-01

    Full Text Available The additive and dominance genetic variances of 5,801 Duroc reproductive and growth records were estimated usingBULPF90 PC-PACK. Estimates were obtained for number born alive (NBA, birth weight (BW, number weaned (NW, andweaning weight (WW. Data were analyzed using two mixed model equations. The first model included fixed effects andrandom effects identifying inbreeding depression, additive gene effect and permanent environments effects. The secondmodel was similar to the first model, but included the dominance genotypic effect. Heritability estimates of NBA, BW, NWand WW from the two models were 0.1558/0.1716, 0.1616/0.1737, 0.0372/0.0874 and 0.1584/0.1516 respectively. Proportionsof dominance effect to total phenotypic variance from the dominance model were 0.1024, 0.1625, 0.0470, and 0.1536 for NBA,BW, NW and WW respectively. Dominance effects were found to have sizable influence on the litter size traits analyzed.Therefore, genetic evaluation with the dominance model (Model 2 is found more appropriate than the animal model (Model 1.

  15. Integrated reservoir characterization: Improvement in heterogeneities stochastic modelling by integration of additional external constraints

    Energy Technology Data Exchange (ETDEWEB)

    Doligez, B.; Eschard, R. [Institut Francais du Petrole, Rueil Malmaison (France); Geffroy, F. [Centre de Geostatistique, Fontainebleau (France)] [and others

    1997-08-01

    The classical approach to construct reservoir models is to start with a fine scale geological model which is informed with petrophysical properties. Then scaling-up techniques allow to obtain a reservoir model which is compatible with the fluid flow simulators. Geostatistical modelling techniques are widely used to build the geological models before scaling-up. These methods provide equiprobable images of the area under investigation, which honor the well data, and which variability is the same than the variability computed from the data. At an appraisal phase, when few data are available, or when the wells are insufficient to describe all the heterogeneities and the behavior of the field, additional constraints are needed to obtain a more realistic geological model. For example, seismic data or stratigraphic models can provide average reservoir information with an excellent areal coverage, but with a poor vertical resolution. New advances in modelisation techniques allow now to integrate this type of additional external information in order to constrain the simulations. In particular, 2D or 3D seismic derived information grids, or sand-shale ratios maps coming from stratigraphic models can be used as external drifts to compute the geological image of the reservoir at the fine scale. Examples are presented to illustrate the use of these new tools, their impact on the final reservoir model, and their sensitivity to some key parameters.

  16. The regression-calibration method for fitting generalized linear models with additive measurement error

    OpenAIRE

    James W. Hardin; Henrik Schmeidiche; Raymond J. Carroll

    2003-01-01

    This paper discusses and illustrates the method of regression calibration. This is a straightforward technique for fitting models with additive measurement error. We present this discussion in terms of generalized linear models (GLMs) following the notation defined in Hardin and Carroll (2003). Discussion will include specified measurement error, measurement error estimated by replicate error-prone proxies, and measurement error estimated by instrumental variables. The discussion focuses on s...

  17. Adjustment of mathematical models and quality of soybean grains in the drying with high temperatures

    Directory of Open Access Journals (Sweden)

    Paulo C. Coradi

    2016-04-01

    Full Text Available ABSTRACT The aim of this study was to evaluate the influence of the initial moisture content of soybeans and the drying air temperatures on drying kinetics and grain quality, and find the best mathematical model that fit the experimental data of drying, effective diffusivity and isosteric heat of desorption. The experimental design was completely randomized (CRD, with a factorial scheme (4 x 2, four drying temperatures (75, 90, 105 and 120 ºC and two initial moisture contents (25 and 19% d.b., with three replicates. The initial moisture content of the product interferes with the drying time. The model of Wang and Singh proved to be more suitable to describe the drying of soybeans to temperature ranges of the drying air of 75, 90, 105 and 120 °C and initial moisture contents of 19 and 25% (d.b.. The effective diffusivity obtained from the drying of soybeans was higher (2.5 x 10-11 m2 s-1 for a temperature of 120 °C and water content of 25% (d.b.. Drying of soybeans at higher temperatures (above 105 °C and higher initial water content (25% d.b. also increases the amount of energy (3894.57 kJ kg-1, i.e., the isosteric heat of desorption necessary to perform the process. Drying air temperature and different initial moisture contents affected the quality of soybean along the drying time (electrical conductivity of 540.35 µS cm-1g-1; however, not affect the final yield of the oil extracted from soybean grains (15.69%.

  18. An ice flow modeling perspective on bedrock adjustment patterns of the Greenland ice sheet

    Directory of Open Access Journals (Sweden)

    M. Olaizola

    2012-11-01

    Full Text Available Since the launch in 2002 of the Gravity Recovery and Climate Experiment (GRACE satellites, several estimates of the mass balance of the Greenland ice sheet (GrIS have been produced. To obtain ice mass changes, the GRACE data need to be corrected for the effect of deformation changes of the Earth's crust. Recently, a new method has been proposed where ice mass changes and bedrock changes are simultaneously solved. Results show bedrock subsidence over almost the entirety of Greenland in combination with ice mass loss which is only half of the currently standing estimates. This subsidence can be an elastic response, but it may however also be a delayed response to past changes. In this study we test whether these subsidence patterns are consistent with ice dynamical modeling results. We use a 3-D ice sheet–bedrock model with a surface mass balance forcing based on a mass balance gradient approach to study the pattern and magnitude of bedrock changes in Greenland. Different mass balance forcings are used. Simulations since the Last Glacial Maximum yield a bedrock delay with respect to the mass balance forcing of nearly 3000 yr and an average uplift at present of 0.3 mm yr−1. The spatial pattern of bedrock changes shows a small central subsidence as well as more intense uplift in the south. These results are not compatible with the gravity based reconstructions showing a subsidence with a maximum in central Greenland, thereby questioning whether the claim of halving of the ice mass change is justified.

  19. Sparse Additive Ordinary Differential Equations for Dynamic Gene Regulatory Network Modeling.

    Science.gov (United States)

    Wu, Hulin; Lu, Tao; Xue, Hongqi; Liang, Hua

    2014-04-02

    The gene regulation network (GRN) is a high-dimensional complex system, which can be represented by various mathematical or statistical models. The ordinary differential equation (ODE) model is one of the popular dynamic GRN models. High-dimensional linear ODE models have been proposed to identify GRNs, but with a limitation of the linear regulation effect assumption. In this article, we propose a sparse additive ODE (SA-ODE) model, coupled with ODE estimation methods and adaptive group LASSO techniques, to model dynamic GRNs that could flexibly deal with nonlinear regulation effects. The asymptotic properties of the proposed method are established and simulation studies are performed to validate the proposed approach. An application example for identifying the nonlinear dynamic GRN of T-cell activation is used to illustrate the usefulness of the proposed method.

  20. Vector generalized linear and additive models with an implementation in R

    CERN Document Server

    Yee, Thomas W

    2015-01-01

    This book presents a statistical framework that expands generalized linear models (GLMs) for regression modelling. The framework shared in this book allows analyses based on many semi-traditional applied statistics models to be performed as a coherent whole. This is possible through the approximately half-a-dozen major classes of statistical models included in the book and the software infrastructure component, which makes the models easily operable.    The book’s methodology and accompanying software (the extensive VGAM R package) are directed at these limitations, and this is the first time the methodology and software are covered comprehensively in one volume. Since their advent in 1972, GLMs have unified important distributions under a single umbrella with enormous implications. The demands of practical data analysis, however, require a flexibility that GLMs do not have. Data-driven GLMs, in the form of generalized additive models (GAMs), are also largely confined to the exponential family. This book ...

  1. Fast Cloud Adjustment to Increasing CO2 in a Superparameterized Climate Model

    Directory of Open Access Journals (Sweden)

    Marat Khairoutdinov

    2012-05-01

    Full Text Available Two-year simulation experiments with a superparameterized climate model, SP-CAM, are performed to understand the fast tropical (30S-30N cloud response to an instantaneous quadrupling of CO2 concentration with SST held fixed at present-day values.The greenhouse effect of the CO2 perturbation quickly warms the tropical land surfaces by an average of 0.5 K. This shifts rising motion, surface precipitation, and cloud cover at all levels from the ocean to the land, with only small net tropical-mean cloud changes. There is a widespread average reduction of about 80 m in the depth of the trade inversion capping the marine boundary layer (MBL over the cooler subtropical oceans.One apparent contributing factor is CO2-enhanced downwelling longwave radiation, which reduces boundary-layer radiative cooling, a primary driver of turbulent entrainment through the trade inversion. A second contributor is a slight CO2-induced heating of the free troposphere above the MBL, which strengthens the trade inversion and also inhibits entrainment. There is a corresponding downward displacement of MBL clouds with a very slight decrease in mean cloud cover and albedo.Two-dimensional cloud-resolving model (CRM simulations of this MBL response are run to steady state using composite SP-CAM simulated thermodynamic and wind profiles from a representative cool subtropical ocean regime, for the control and 4xCO2 cases. Simulations with a CRM grid resolution equal to that of SP-CAM are compared with much finer resolution simulations. The coarse-resolution simulations maintain a cloud fraction and albedo comparable to SP-CAM, but the fine-resolution simulations have a much smaller cloud fraction. Nevertheless, both CRM configurations simulate a reduction in inversion height comparable to SP-CAM. The changes in low cloud cover and albedo in the CRM simulations are small, but both simulations predict a slight reduction in low cloud albedo as in SP-CAM.

  2. Optimizing simulated fertilizer additions using a genetic algorithm with a nutrient uptake model

    Science.gov (United States)

    Wendell P. Cropper; N.B. Comerford

    2005-01-01

    Intensive management of pine plantations in the southeastern coastal plain typically involves weed and pest control, and the addition of fertilizer to meet the high nutrient demand of rapidly growing pines. In this study we coupled a mechanistic nutrient uptake model (SSAND, soil supply and nutrient demand) with a genetic algorithm (GA) in order to estimate the minimum...

  3. Parametrically Guided Generalized Additive Models with Application to Mergers and Acquisitions Data.

    Science.gov (United States)

    Fan, Jianqing; Maity, Arnab; Wang, Yihui; Wu, Yichao

    2013-01-01

    Generalized nonparametric additive models present a flexible way to evaluate the effects of several covariates on a general outcome of interest via a link function. In this modeling framework, one assumes that the effect of each of the covariates is nonparametric and additive. However, in practice, often there is prior information available about the shape of the regression functions, possibly from pilot studies or exploratory analysis. In this paper, we consider such situations and propose an estimation procedure where the prior information is used as a parametric guide to fit the additive model. Specifically, we first posit a parametric family for each of the regression functions using the prior information (parametric guides). After removing these parametric trends, we then estimate the remainder of the nonparametric functions using a nonparametric generalized additive model, and form the final estimates by adding back the parametric trend. We investigate the asymptotic properties of the estimates and show that when a good guide is chosen, the asymptotic variance of the estimates can be reduced significantly while keeping the asymptotic variance same as the unguided estimator. We observe the performance of our method via a simulation study and demonstrate our method by applying to a real data set on mergers and acquisitions.

  4. Declarations pursuant to the Articles 2 and 3 of the Model Additional Protocol

    International Nuclear Information System (INIS)

    Fernandez Moreno, Sonia

    2001-01-01

    Articles 2 and 3 of the Model Additional Protocol specify the content and the time limits of the information to be provided by the States into the framework of the Safeguard Agreements. To standardize the presentation of this information the IAEA has prepared guidelines for the preparation of the documents. A detailed explanation of the guidelines is given in the paper

  5. 78 FR 12271 - Wireline Competition Bureau Seeks Additional Comment In Connect America Cost Model Virtual Workshop

    Science.gov (United States)

    2013-02-22

    ... (202) 863-2893, facsimile (202) 863-2898, or via the Internet at http://www.bcpiweb.com . In addition, the Virtual Workshop may be accessed via the Internet at http://www.fcc.gov/blog/wcb-cost-model... this proceeding. The Bureau will not rely on anonymous comments posted during the workshop in reaching...

  6. Modeling a Change in Flowrate through Detention or Additional Pavement on the Receiving Stream : Final Report

    Science.gov (United States)

    2017-11-01

    The addition or removal of flow from a stream affects the water surface downstream and possibly upstream. The extent of such effects is generally determined by modeling the receiving stream. Guidance that concisely describes how far up/downstream a h...

  7. A Bayesian Additive Model for Understanding Public Transport Usage in Special Events

    DEFF Research Database (Denmark)

    Rodrigues, Filipe; Borysov, Stanislav S.; Ribeiro, Bernardete

    2017-01-01

    additive model with Gaussian process components that combines smart card records from public transport with context information about events that is continuously mined from the Web. We develop an efficient approximate inference algorithm using expectation propagation, which allows us to predict the total...

  8. Discontinuity of Family Planning in Nigeria: A Geo-Additive Model ...

    African Journals Online (AJOL)

    PROF. OLIVER OSUAGWA

    2015-06-01

    Jun 1, 2015 ... This study explored the factors associated with discontinuance of Family Planning (FP) in Nigeria. A geo-additive model was ... education, wealth, religion, culture are responsible for women's attitude to ..... Planning Indicators by Wealth in Two South Asian Countries. www.cpc.unc.edu/measure. 25. Nyauchi ...

  9. Representational Flexibility and Problem-Solving Ability in Fraction and Decimal Number Addition: A Structural Model

    Science.gov (United States)

    Deliyianni, Eleni; Gagatsis, Athanasios; Elia, Iliada; Panaoura, Areti

    2016-01-01

    The aim of this study was to propose and validate a structural model in fraction and decimal number addition, which is founded primarily on a synthesis of major theoretical approaches in the field of representations in Mathematics and also on previous research on the learning of fractions and decimals. The study was conducted among 1,701 primary…

  10. Modeling the use of sulfate additives for potassium chloride destruction in biomass combustion

    DEFF Research Database (Denmark)

    Wu, Hao; Grell, Morten Nedergaard; Jespersen, Jacob Boll

    2013-01-01

    was affected by the decomposition temperature. Based on the experimental data, a model was proposed to simulate the sulfation of KCl by different sulfate addition, and the simulation results were compared with pilot-scale experiments conducted in a bubbling fluidized bed reactor. The simulation results...

  11. Modeling grain size adjustments in the downstream reach following run-of-river development

    Science.gov (United States)

    Fuller, Theodore K.; Venditti, Jeremy G.; Nelson, Peter A.; Palen, Wendy J.

    2016-04-01

    Disruptions to sediment supply continuity caused by run-of-river (RoR) hydropower development have the potential to cause downstream changes in surface sediment grain size which can influence the productivity of salmon habitat. The most common approach to understanding the impacts of RoR hydropower is to study channel changes in the years following project development, but by then, any impacts are manifest and difficult to reverse. Here we use a more proactive approach, focused on predicting impacts in the project planning stage. We use a one-dimensional morphodynamic model to test the hypothesis that the greatest risk of geomorphic change and impact to salmon habitat from a temporary sediment supply disruption exists where predevelopment sediment supply is high and project design creates substantial sediment storage volume. We focus on the potential impacts in the reach downstream of a powerhouse for a range of development scenarios that are typical of projects developed in the Pacific Northwest and British Columbia. Results indicate that increases in the median bed surface size (D50) are minor if development occurs on low sediment supply streams (<1 mm for supply rates 1 × 10-5 m2 s-1 or lower), and substantial for development on high sediment supply streams (8-30 mm for supply rates between 5.5 × 10-4 and 1 × 10-3 m2 s-1). However, high sediment supply streams recover rapidly to the predevelopment surface D50 (˜1 year) if sediment supply can be reestablished.

  12. Formation and reduction of carcinogenic furan in various model systems containing food additives.

    Science.gov (United States)

    Kim, Jin-Sil; Her, Jae-Young; Lee, Kwang-Geun

    2015-12-15

    The aim of this study was to analyse and reduce furan in various model systems. Furan model systems consisting of monosaccharides (0.5M glucose and ribose), amino acids (0.5M alanine and serine) and/or 1.0M ascorbic acid were heated at 121°C for 25 min. The effects of food additives (each 0.1M) such as metal ions (iron sulphate, magnesium sulphate, zinc sulphate and calcium sulphate), antioxidants (BHT and BHA), and sodium sulphite on the formation of furan were measured. The level of furan formed in the model systems was 6.8-527.3 ng/ml. The level of furan in the model systems of glucose/serine and glucose/alanine increased 7-674% when food additives were added. In contrast, the level of furan decreased by 18-51% in the Maillard reaction model systems that included ribose and alanine/serine with food additives except zinc sulphate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. NB-PLC channel modelling with cyclostationary noise addition & OFDM implementation for smart grid

    Science.gov (United States)

    Thomas, Togis; Gupta, K. K.

    2016-03-01

    Power line communication (PLC) technology can be a viable solution for the future ubiquitous networks because it provides a cheaper alternative to other wired technology currently being used for communication. In smart grid Power Line Communication (PLC) is used to support communication with low rate on low voltage (LV) distribution network. In this paper, we propose the channel modelling of narrowband (NB) PLC in the frequency range 5 KHz to 500 KHz by using ABCD parameter with cyclostationary noise addition. Behaviour of the channel was studied by the addition of 11KV/230V transformer, by varying load location and load. Bit error rate (BER) Vs signal to noise ratio SNR) was plotted for the proposed model by employing OFDM. Our simulation results based on the proposed channel model show an acceptable performance in terms of bit error rate versus signal to noise ratio, which enables communication required for smart grid applications.

  14. A parallelized three-dimensional cellular automaton model for grain growth during additive manufacturing

    Science.gov (United States)

    Lian, Yanping; Lin, Stephen; Yan, Wentao; Liu, Wing Kam; Wagner, Gregory J.

    2018-01-01

    In this paper, a parallelized 3D cellular automaton computational model is developed to predict grain morphology for solidification of metal during the additive manufacturing process. Solidification phenomena are characterized by highly localized events, such as the nucleation and growth of multiple grains. As a result, parallelization requires careful treatment of load balancing between processors as well as interprocess communication in order to maintain a high parallel efficiency. We give a detailed summary of the formulation of the model, as well as a description of the communication strategies implemented to ensure parallel efficiency. Scaling tests on a representative problem with about half a billion cells demonstrate parallel efficiency of more than 80% on 8 processors and around 50% on 64; loss of efficiency is attributable to load imbalance due to near-surface grain nucleation in this test problem. The model is further demonstrated through an additive manufacturing simulation with resulting grain structures showing reasonable agreement with those observed in experiments.

  15. Experimental validation of a fuel additive assisted regeneration model in silicon carbide diesel filters

    Energy Technology Data Exchange (ETDEWEB)

    Stratakis, G.A.; Pontikakis, G.N.; Stamatelos, A.M. [University of Thessaly, Volos (Greece). Mechanical and Industrial Engineering Dept.

    2004-07-01

    In this paper, an experimental validation procedure is applied to an improved one-dimensional model of fuel additive assisted regeneration of a diesel particulate filter. Full-scale tests on an engine bench of the regeneration behaviour of a diesel filter fitted to a modern diesel engine run on catalyst-doped fuel are employed for this purpose. The main objectives of the validation procedure concern the ability of the model to predict the effects of exhaust mass flowrate, initial soot loading mass, volatile organic fraction of the soot and additive concentration in the fuel. The results of the validation procedure are intended to demonstrate the scope and extent of applicability of models of this type to real-world design and optimization studies with diesel filters. (author)

  16. Salary adjustments

    CERN Multimedia

    HR Department

    2008-01-01

    In accordance with decisions taken by the Finance Committee and Council in December 2007, salaries are adjusted with effect from 1 January 2008. Scale of basic salaries and scale of stipends paid to fellows (Annex R A 5 and R A 6 respectively): increased by 0.71% with effect from 1 January 2008. As a result of the stability of the Geneva consumer price index, following elements do not increase: a) Family Allowance, Child Allowance and Infant Allowance (Annex R A 3). b) Reimbursement of education fees: maximum amounts of reimbursement (Annex R A 4.01) for the academic year 2007/2008. Related adjustments will be implemented, wherever applicable, to Paid Associates and Students. As in the past, the actual percentage increase of each salary position may vary, due to the application of a constant step value and the rounding effects. Human Resources Department Tel. 73566

  17. Salary adjustments

    CERN Multimedia

    HR Department

    2008-01-01

    In accordance with decisions taken by the Finance Committee and Council in December 2007, salaries are adjusted with effect from 1 January 2008. Scale of basic salaries and scale of stipends paid to fellows (Annex R A 5 and R A 6 respectively): increased by 0.71% with effect from 1 January 2008. As a result of the stability of the Geneva consumer price index, the following elements do not increase: a)\tFamily Allowance, Child Allowance and Infant Allowance (Annex R A 3); b)\tReimbursement of education fees: maximum amounts of reimbursement (Annex R A 4.01) for the academic year 2007/2008. Related adjustments will be applied, wherever applicable, to Paid Associates and Students. As in the past, the actual percentage increase of each salary position may vary, due to the application of a constant step value and rounding effects. Human Resources Department Tel. 73566

  18. Shaft adjuster

    Science.gov (United States)

    Harry, Herbert H.

    1989-01-01

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

  19. The potential application of European market research data in dietary exposure modelling of food additives.

    Science.gov (United States)

    Tennant, David Robin; Bruyninckx, Chris

    2018-03-01

    Consumer exposure assessments for food additives are incomplete without information about the proportions of foods in each authorised category that contain the additive. Such information has been difficult to obtain but the Mintel Global New Products Database (GNPD) provides information about product launches across Europe over the past 20 years. These data can be searched to identify products with specific additives listed on product labels and the numbers compared with total product launches for food and drink categories in the same database to determine the frequency of occurrence. There are uncertainties associated with the data but these can be managed by adopting a cautious and conservative approach. GNPD data can be mapped with authorised food categories and with food descriptions used in the EFSA Comprehensive European Food Consumption Surveys Database for exposure modelling. The data, when presented as percent occurrence, could be incorporated into the EFSA ANS Panel's 'brand-loyal/non-brand loyal exposure model in a quantitative way. Case studies of preservative, antioxidant, colour and sweetener additives showed that the impact of including occurrence data is greatest in the non-brand loyal scenario. Recommendations for future research include identifying occurrence data for alcoholic beverages, linking regulatory food codes, FoodEx and GNPD product descriptions, developing the use of occurrence data for carry-over foods and improving understanding of brand loyalty in consumer exposure models.

  20. Lifetime effectiveness of mifamurtide addition to chemotherapy in nonmetastatic and metastatic osteosarcoma: a Markov process model analysis.

    Science.gov (United States)

    Song, Hyun Jin; Lee, Jun Ah; Han, Euna; Lee, Eui-Kyung

    2015-09-01

    The mortality and progression rates in osteosarcoma differ depending on the presence of metastasis. A decision model would be useful for estimating long-term effectiveness of treatment with limited clinical trial data. The aim of this study was to explore the lifetime effectiveness of the addition of mifamurtide to chemotherapy for patients with metastatic and nonmetastatic osteosarcoma. The target population was osteosarcoma patients with or without metastasis. A Markov process model was used, whose time horizon was lifetime with a starting age of 13 years. There were five health states: disease-free (DF), recurrence, post-recurrence disease-free, post-recurrence disease-progression, and death. Transition probabilities of the starting state, DF, were calculated from the INT-0133 clinical trials for chemotherapy with and without mifamurtide. Quality-adjusted life-years (QALY) increased upon addition of mifamurtide to chemotherapy by 10.5 % (10.13 and 9.17 QALY with and without mifamurtide, respectively) and 45.2 % (7.23 and 4.98 QALY with and without mifamurtide, respectively) relative to the lifetime effectiveness of chemotherapy in nonmetastatic and metastatic osteosarcoma, respectively. Life-years gained (LYG) increased by 10.1 % (13.10 LYG with mifamurtide and 11.90 LYG without mifamurtide) in nonmetastatic patients and 42.2 % (9.43 LYG with mifamurtide and 6.63 LYG without mifamurtide) in metastatic osteosarcoma patients. The Markov model analysis showed that chemotherapy with mifamurtide improved the lifetime effectiveness compared to chemotherapy alone in both nonmetastatic and metastatic osteosarcoma. Relative effectiveness of the therapy was higher in metastatic than nonmetastatic osteosarcoma over lifetime. However, absolute lifetime effectiveness was higher in nonmetastatic than metastatic osteosarcoma.

  1. Efficient semiparametric estimation in generalized partially linear additive models for longitudinal/clustered data

    KAUST Repository

    Cheng, Guang

    2014-02-01

    We consider efficient estimation of the Euclidean parameters in a generalized partially linear additive models for longitudinal/clustered data when multiple covariates need to be modeled nonparametrically, and propose an estimation procedure based on a spline approximation of the nonparametric part of the model and the generalized estimating equations (GEE). Although the model in consideration is natural and useful in many practical applications, the literature on this model is very limited because of challenges in dealing with dependent data for nonparametric additive models. We show that the proposed estimators are consistent and asymptotically normal even if the covariance structure is misspecified. An explicit consistent estimate of the asymptotic variance is also provided. Moreover, we derive the semiparametric efficiency score and information bound under general moment conditions. By showing that our estimators achieve the semiparametric information bound, we effectively establish their efficiency in a stronger sense than what is typically considered for GEE. The derivation of our asymptotic results relies heavily on the empirical processes tools that we develop for the longitudinal/clustered data. Numerical results are used to illustrate the finite sample performance of the proposed estimators. © 2014 ISI/BS.

  2. Study of abrasive resistance of foundries models obtained with use of additive technology

    Science.gov (United States)

    Ol'khovik, Evgeniy

    2017-10-01

    A problem of determination of resistance of the foundry models and patterns from ABS (PLA) plastic, obtained by the method of 3D printing with using FDM additive technology, to abrasive wear and resistance in the environment of foundry sand mould is considered in the present study. The description of a technique and equipment for tests of castings models and patterns for wear is provided in the article. The manufacturing techniques of models with the use of the 3D printer (additive technology) are described. The scheme with vibration load was applied to samples tests. For the most qualitative research of influence of sandy mix on plastic, models in real conditions of abrasive wear have been organized. The results also examined the application of acrylic paintwork to the plastic model and a two-component coating. The practical offers and recommendation on production of master models with the use of FDM technology allowing one to reach indicators of durability, exceeding 2000 cycles of moulding in foundry sand mix, are described.

  3. Linking livestock snow disaster mortality and environmental stressors in the Qinghai-Tibetan Plateau: Quantification based on generalized additive models.

    Science.gov (United States)

    Li, Yijia; Ye, Tao; Liu, Weihang; Gao, Yu

    2018-06-01

    Livestock snow disaster occurs widely in Central-to-Eastern Asian temperate and alpine grasslands. The effects of snow disaster on livestock involve a complex interaction between precipitation, vegetation, livestock, and herder communities. Quantifying the relationship among livestock mortality, snow hazard intensity, and seasonal environmental stressors is of great importance for snow disaster early warning, risk assessments, and adaptation strategies. Using a wide-spatial extent, long-time series, and event-based livestock snow disaster dataset, this study quantified those relationships and established a quantitative model of livestock mortality for prediction purpose for the Qinghai-Tibet Plateau region. Estimations using generalized additive models (GAMs) were shown to accurately predict livestock mortality and mortality rate due to snow disaster, with adjusted-R 2 up to 0.794 and 0.666, respectively. These results showed that a longer snow disaster duration, lower temperatures during the disaster, and a drier summer with less vegetation all contribute significantly and non-linearly to higher mortality (rate), after controlling for elevation and socioeconomic conditions. These results can be readily applied to risk assessment and risk-based adaptation actions. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The effect of tailor-made additives on crystal growth of methyl paraben: Experiments and modelling

    Science.gov (United States)

    Cai, Zhihui; Liu, Yong; Song, Yang; Guan, Guoqiang; Jiang, Yanbin

    2017-03-01

    In this study, methyl paraben (MP) was selected as the model component, and acetaminophen (APAP), p-methyl acetanilide (PMAA) and acetanilide (ACET), which share the similar molecular structure as MP, were selected as the three tailor-made additives to study the effect of tailor-made additives on the crystal growth of MP. HPLC results indicated that the MP crystals induced by the three additives contained MP only. Photographs of the single crystals prepared indicated that the morphology of the MP crystals was greatly changed by the additives, but PXRD and single crystal diffraction results illustrated that the MP crystals were the same polymorph only with different crystal habits, and no new crystal form was found compared with other references. To investigate the effect of the additives on the crystal growth, the interaction between additives and facets was discussed in detail using the DFT methods and MD simulations. The results showed that APAP, PMAA and ACET would be selectively adsorbed on the growth surfaces of the crystal facets, which induced the change in MP crystal habits.

  5. Glacial isostatic adjustment at the Laurentide ice sheet margin: Models and observations in the Great Lakes region

    Science.gov (United States)

    Braun, Alexander; Kuo, Chung-Yen; Shum, C. K.; Wu, Patrick; van der Wal, Wouter; Fotopoulos, Georgia

    2008-10-01

    Glacial Isostatic Adjustment (GIA) modelling in North America relies on relative sea level information which is primarily obtained from areas far away from the uplift region. The lack of accurate geodetic observations in the Great Lakes region, which is located in the transition zone between uplift and subsidence due to the deglaciation of the Laurentide ice sheet, has prevented more detailed studies of this former margin of the ice sheet. Recently, observations of vertical crustal motion from improved GPS network solutions and combined tide gauge and satellite altimetry solutions have become available. This study compares these vertical motion observations with predictions obtained from 70 different GIA models. The ice sheet margin is distinct from the centre and far field of the uplift because the sensitivity of the GIA process towards Earth parameters such as mantle viscosity is very different. Specifically, the margin area is most sensitive to the uppermost mantle viscosity and allows for better constraints of this parameter. The 70 GIA models compared herein have different ice loading histories (ICE-3/4/5G) and Earth parameters including lateral heterogeneities. The root-mean-square differences between the 6 best models and the two sets of observations (tide gauge/altimetry and GPS) are 0.66 and 1.57 mm/yr, respectively. Both sets of independent observations are highly correlated and show a very similar fit to the models, which indicates their consistent quality. Therefore, both data sets can be considered as a means for constraining and assessing the quality of GIA models in the Great Lakes region and the former margin of the Laurentide ice sheet.

  6. Use of additive technologies for practical working with complex models for foundry technologies

    Science.gov (United States)

    Olkhovik, E.; Butsanets, A. A.; Ageeva, A. A.

    2016-07-01

    The article presents the results of research of additive technology (3D printing) application for developing a geometrically complex model of castings parts. Investment casting is well known and widely used technology for the production of complex parts. The work proposes the use of a 3D printing technology for manufacturing models parts, which are removed by thermal destruction. Traditional methods of equipment production for investment casting involve the use of manual labor which has problems with dimensional accuracy, and CNC technology which is less used. Such scheme is low productive and demands considerable time. We have offered an alternative method which consists in printing the main knots using a 3D printer (PLA and ABS) with a subsequent production of castings models from them. In this article, the main technological methods are considered and their problems are discussed. The dimensional accuracy of models in comparison with investment casting technology is considered as the main aspect.

  7. Modeling of sulfation of potassium chloride by ferric sulfate addition during grate-firing of biomass

    DEFF Research Database (Denmark)

    Wu, Hao; Jespersen, Jacob Boll; Aho, Martti

    2013-01-01

    Potassium chloride, KCl, formed from critical ash-forming elements released during combustion may lead to severe ash deposition and corrosion problems in biomass-fired boilers. Ferric sulfate, Fe2(SO4)3 is an effective additive, which produces sulfur oxides (SO2 and SO3) to convert KCl to the less...... harmful K2SO4. In the present study the decomposition of ferric sulfate is studied in a fast-heating rate thermogravimetric analyzer (TGA), and a kinetic model is proposed to describe the decomposition process. The yields of SO2 and SO3 from ferric sulfate decomposition are investigated in a laboratory......-scale tube reactor. It is revealed that approximately 40% of the sulfur is released as SO3, the remaining fraction being released as SO2. The proposed decomposition model of ferric sulfate is combined with a detailed gas phase kinetic model of KCl sulfation, and a simplified model of K2SO4 condensation...

  8. Using 3D Printing (Additive Manufacturing) to Produce Low-Cost Simulation Models for Medical Training.

    Science.gov (United States)

    Lichtenberger, John P; Tatum, Peter S; Gada, Satyen; Wyn, Mark; Ho, Vincent B; Liacouras, Peter

    2018-03-01

    This work describes customized, task-specific simulation models derived from 3D printing in clinical settings and medical professional training programs. Simulation models/task trainers have an array of purposes and desired achievements for the trainee, defining that these are the first step in the production process. After this purpose is defined, computer-aided design and 3D printing (additive manufacturing) are used to create a customized anatomical model. Simulation models then undergo initial in-house testing by medical specialists followed by a larger scale beta testing. Feedback is acquired, via surveys, to validate effectiveness and to guide or determine if any future modifications and/or improvements are necessary. Numerous custom simulation models have been successfully completed with resulting task trainers designed for procedures, including removal of ocular foreign bodies, ultrasound-guided joint injections, nerve block injections, and various suturing and reconstruction procedures. These task trainers have been frequently utilized in the delivery of simulation-based training with increasing demand. 3D printing has been integral to the production of limited-quantity, low-cost simulation models across a variety of medical specialties. In general, production cost is a small fraction of a commercial, generic simulation model, if available. These simulation and training models are customized to the educational need and serve an integral role in the education of our military health professionals.

  9. Worst case prediction of additives migration from polystyrene for food safety purposes: a model update

    DEFF Research Database (Denmark)

    Martinez Lopez, Brais; Gontard, Nathalie; Peyron, Stephane

    2018-01-01

    A reliable prediction of migration levels of plastic additives into food requires a robust estimation of diffusivity. Predictive modelling of diffusivity as recommended by the EU commission is carried out using a semi-empirical equation that relies on two polymer-dependent parameters. These param......A reliable prediction of migration levels of plastic additives into food requires a robust estimation of diffusivity. Predictive modelling of diffusivity as recommended by the EU commission is carried out using a semi-empirical equation that relies on two polymer-dependent parameters....... These parameters were determined for the polymers most used by packaging industry (LLDPE, HDPE, PP, PET, PS, HIPS) from the diffusivity data available at that time. In the specific case of general purpose polystyrene, the diffusivity data published since then shows that the use of the equation with the original...

  10. An additive-multiplicative mean residual life model for right-censored data.

    Science.gov (United States)

    Cai, Jingheng; He, Haijin; Song, Xinyuan; Sun, Liuquan

    2017-05-01

    Many studies have focused on determining the effect of the body mass index (BMI) on the mortality in different cohorts. In this article, we propose an additive-multiplicative mean residual life (MRL) model to assess the effects of BMI and other risk factors on the MRL function of survival time in a cohort of Chinese type 2 diabetic patients. The proposed model can simultaneously manage additive and multiplicative risk factors and provide a comprehensible interpretation of their effects on the MRL function of interest. We develop an estimation procedure through pseudo partial score equations to obtain parameter estimates. We establish the asymptotic properties of the proposed estimators and conduct simulations to demonstrate the performance of the proposed method. The application of the procedure to a study on the life expectancy of type 2 diabetic patients reveals new insights into the extension of the life expectancy of such patients. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    DEFF Research Database (Denmark)

    Scheike, Thomas; Martinussen, T; Zhang, MJ

    2011-01-01

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

  12. Patient-specific in vitro models for hemodynamic analysis of congenital heart disease - Additive manufacturing approach.

    Science.gov (United States)

    Medero, Rafael; García-Rodríguez, Sylvana; François, Christopher J; Roldán-Alzate, Alejandro

    2017-03-21

    Non-invasive hemodynamic assessment of total cavopulmonary connection (TCPC) is challenging due to the complex anatomy. Additive manufacturing (AM) is a suitable alternative for creating patient-specific in vitro models for flow measurements using four-dimensional (4D) Flow MRI. These in vitro systems have the potential to serve as validation for computational fluid dynamics (CFD), simulating different physiological conditions. This study investigated three different AM technologies, stereolithography (SLA), selective laser sintering (SLS) and fused deposition modeling (FDM), to determine differences in hemodynamics when measuring flow using 4D Flow MRI. The models were created using patient-specific MRI data from an extracardiac TCPC. These models were connected to a perfusion pump circulating water at three different flow rates. Data was processed for visualization and quantification of velocity, flow distribution, vorticity and kinetic energy. These results were compared between each model. In addition, the flow distribution obtained in vitro was compared to in vivo. The results showed significant difference in velocities measured at the outlets of the models that required internal support material when printing. Furthermore, an ultrasound flow sensor was used to validate flow measurements at the inlets and outlets of the in vitro models. These results were highly correlated to those measured with 4D Flow MRI. This study showed that commercially available AM technologies can be used to create patient-specific vascular models for in vitro hemodynamic studies at reasonable costs. However, technologies that do not require internal supports during manufacturing allow smoother internal surfaces, which makes them better suited for flow analyses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Modeling of Ti-W Solidification Microstructures Under Additive Manufacturing Conditions

    Science.gov (United States)

    Rolchigo, Matthew R.; Mendoza, Michael Y.; Samimi, Peyman; Brice, David A.; Martin, Brian; Collins, Peter C.; LeSar, Richard

    2017-07-01

    Additive manufacturing (AM) processes have many benefits for the fabrication of alloy parts, including the potential for greater microstructural control and targeted properties than traditional metallurgy processes. To accelerate utilization of this process to produce such parts, an effective computational modeling approach to identify the relationships between material and process parameters, microstructure, and part properties is essential. Development of such a model requires accounting for the many factors in play during this process, including laser absorption, material addition and melting, fluid flow, various modes of heat transport, and solidification. In this paper, we start with a more modest goal, to create a multiscale model for a specific AM process, Laser Engineered Net Shaping (LENS™), which couples a continuum-level description of a simplified beam melting problem (coupling heat absorption, heat transport, and fluid flow) with a Lattice Boltzmann-cellular automata (LB-CA) microscale model of combined fluid flow, solute transport, and solidification. We apply this model to a binary Ti-5.5 wt pct W alloy and compare calculated quantities, such as dendrite arm spacing, with experimental results reported in a companion paper.

  14. Model for Assembly Line Re-Balancing Considering Additional Capacity and Outsourcing to Face Demand Fluctuations

    Science.gov (United States)

    Samadhi, TMAA; Sumihartati, Atin

    2016-02-01

    The most critical stage in a garment industry is sewing process, because generally, it consists of a number of operations and a large number of sewing machines for each operation. Therefore, it requires a balancing method that can assign task to work station with balance workloads. Many studies on assembly line balancing assume a new assembly line, but in reality, due to demand fluctuation and demand increased a re-balancing is needed. To cope with those fluctuating demand changes, additional capacity can be carried out by investing in spare sewing machine and paying for sewing service through outsourcing. This study develops an assembly line balancing (ALB) model on existing line to cope with fluctuating demand change. Capacity redesign is decided if the fluctuation demand exceeds the available capacity through a combination of making investment on new machines and outsourcing while considering for minimizing the cost of idle capacity in the future. The objective of the model is to minimize the total cost of the line assembly that consists of operating costs, machine cost, adding capacity cost, losses cost due to idle capacity and outsourcing costs. The model develop is based on an integer programming model. The model is tested for a set of data of one year demand with the existing number of sewing machines of 41 units. The result shows that additional maximum capacity up to 76 units of machine required when there is an increase of 60% of the average demand, at the equal cost parameters..

  15. A QCD derivation of the additive quark model from two and three gluon exchanges

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1982-06-01

    The contributions to the Pomeron from two and three gluon exchanges are shown to give the correct combinatorial factors for the additive quark model relation between meson and baryon Pomeron couplings, even though two-quark and three-quark operators are involved. Similar results hold for the contributions to hadron masses from three-gluon vertices as well as one-gluon exchange. The color algebra reduces the multiquark couplings to a linear function of quark number. (author)

  16. PULSE: Integrated Parametric Modeling for a Shading System: From Daylight Optimization to Additive Manufacturing

    OpenAIRE

    Teeling, M.V.M.T.; Turrin, M.; de Ruiter, P.; Turrin, Michela; Peters, Brady; O'Brien, William; Stouffs, Rudi; Dogan, Timur

    2017-01-01

    This paper presents a parametric approach to an integrated and performance-oriented design, from the conceptual design phase towards materialization. The novelty occurs in the use of parametric models as a way of integrating multidisciplinary design constraints, from daylight optimization to the additive manufacturing process. The work focuses on the case of a customized sun-shading system that tailors daylighting effects for a fully glazed façade of the alleged PULSE building.The overall wor...

  17. Development of a QTL-environment-based predictive model for node addition rate in common bean.

    Science.gov (United States)

    Zhang, Li; Gezan, Salvador A; Eduardo Vallejos, C; Jones, James W; Boote, Kenneth J; Clavijo-Michelangeli, Jose A; Bhakta, Mehul; Osorno, Juan M; Rao, Idupulapati; Beebe, Stephen; Roman-Paoli, Elvin; Gonzalez, Abiezer; Beaver, James; Ricaurte, Jaumer; Colbert, Raphael; Correll, Melanie J

    2017-05-01

    This work reports the effects of the genetic makeup, the environment and the genotype by environment interactions for node addition rate in an RIL population of common bean. This information was used to build a predictive model for node addition rate. To select a plant genotype that will thrive in targeted environments it is critical to understand the genotype by environment interaction (GEI). In this study, multi-environment QTL analysis was used to characterize node addition rate (NAR, node day - 1 ) on the main stem of the common bean (Phaseolus vulgaris L). This analysis was carried out with field data of 171 recombinant inbred lines that were grown at five sites (Florida, Puerto Rico, 2 sites in Colombia, and North Dakota). Four QTLs (Nar1, Nar2, Nar3 and Nar4) were identified, one of which had significant QTL by environment interactions (QEI), that is, Nar2 with temperature. Temperature was identified as the main environmental factor affecting NAR while day length and solar radiation played a minor role. Integration of sites as covariates into a QTL mixed site-effect model, and further replacing the site component with explanatory environmental covariates (i.e., temperature, day length and solar radiation) yielded a model that explained 73% of the phenotypic variation for NAR with root mean square error of 16.25% of the mean. The QTL consistency and stability was examined through a tenfold cross validation with different sets of genotypes and these four QTLs were always detected with 50-90% probability. The final model was evaluated using leave-one-site-out method to assess the influence of site on node addition rate. These analyses provided a quantitative measure of the effects on NAR of common beans exerted by the genetic makeup, the environment and their interactions.

  18. Comparison of prosthetic models produced by traditional and additive manufacturing methods.

    Science.gov (United States)

    Park, Jin-Young; Kim, Hae-Young; Kim, Ji-Hwan; Kim, Jae-Hong; Kim, Woong-Chul

    2015-08-01

    The purpose of this study was to verify the clinical-feasibility of additive manufacturing by comparing the accuracy of four different manufacturing methods for metal coping: the conventional lost wax technique (CLWT); subtractive methods with wax blank milling (WBM); and two additive methods, multi jet modeling (MJM), and micro-stereolithography (Micro-SLA). Thirty study models were created using an acrylic model with the maxillary upper right canine, first premolar, and first molar teeth. Based on the scan files from a non-contact blue light scanner (Identica; Medit Co. Ltd., Seoul, Korea), thirty cores were produced using the WBM, MJM, and Micro-SLA methods, respectively, and another thirty frameworks were produced using the CLWT method. To measure the marginal and internal gap, the silicone replica method was adopted, and the silicone images obtained were evaluated using a digital microscope (KH-7700; Hirox, Tokyo, Japan) at 140X magnification. Analyses were performed using two-way analysis of variance (ANOVA) and Tukey post hoc test (α=.05). The mean marginal gaps and internal gaps showed significant differences according to tooth type (Pmanufacturing method (Pmanufacturing methods were within a clinically allowable range, and, thus, the clinical use of additive manufacturing methods is acceptable as an alternative to the traditional lost wax-technique and subtractive manufacturing.

  19. Improving the Process of Adjusting the Parameters of Finite Element Models of Healthy Human Intervertebral Discs by the Multi-Response Surface Method

    Science.gov (United States)

    Somovilla Gómez, Fátima

    2017-01-01

    The kinematic behavior of models that are based on the finite element method (FEM) for modeling the human body depends greatly on an accurate estimate of the parameters that define such models. This task is complex, and any small difference between the actual biomaterial model and the simulation model based on FEM can be amplified enormously in the presence of nonlinearities. The current paper attempts to demonstrate how a combination of the FEM and the MRS methods with desirability functions can be used to obtain the material parameters that are most appropriate for use in defining the behavior of Finite Element (FE) models of the healthy human lumbar intervertebral disc (IVD). The FE model parameters were adjusted on the basis of experimental data from selected standard tests (compression, flexion, extension, shear, lateral bending, and torsion) and were developed as follows: First, three-dimensional parameterized FE models were generated on the basis of the mentioned standard tests. Then, 11 parameters were selected to define the proposed parameterized FE models. For each of the standard tests, regression models were generated using MRS to model the six stiffness and nine bulges of the healthy IVD models that were created by changing the parameters of the FE models. The optimal combination of the 11 parameters was based on three different adjustment criteria. The latter, in turn, were based on the combination of stiffness and bulges that were obtained from the standard test FE simulations. The first adjustment criteria considered stiffness and bulges to be equally important in the adjustment of FE model parameters. The second adjustment criteria considered stiffness as most important, whereas the third considered the bulges to be most important. The proposed adjustment methods were applied to a medium-sized human IVD that corresponded to the L3–L4 lumbar level with standard dimensions of width = 50 mm, depth = 35 mm, and height = 10 mm. Agreement between the

  20. Development of putative probiotics as feed additives: validation in a porcine-specific gastrointestinal tract model.

    Science.gov (United States)

    Yeo, Soyoung; Lee, Suro; Park, Hyunjoon; Shin, Heuynkil; Holzapfel, Wilhelm; Huh, Chul Sung

    2016-12-01

    Enforced restrictions on the use of antibiotics as growth promoters (AGPs) in animal production have prompted investigations into alternative feed additives in recent decades. Probiotics are currently the main feed additive used in livestock. However, the selection of probiotic candidates relies on human-based methods and little is known about the verification criteria for host-specific selection. We investigated the probiotic potential of Lactobacillus salivarius strains isolated from fed pig feces for their use as porcine feed additives. Two methods were developed that simulated the pig gastrointestinal (GI) tract and the intestinal epithelium, and these were compared with human-based in vitro methods and used for selecting porcine probiotics. Lactobacillus salivarius strain LS6 was identified as a promising probiotic strain for potential use as a porcine feed additive. This strain prevented disruption of the epithelial integrity of pig small intestine (PSI) cells by inhibiting the adherence of enterotoxigenic Escherichia coli K88. It also showed high survival rates in the in vitro pig GI tract model and good adhesion to PSI cells. We propose that host target-specific screening and validation methods are important tools in the development of effective probiotic feed additives, and this approach may support future-oriented agriculture.

  1. GenoGAM: genome-wide generalized additive models for ChIP-Seq analysis.

    Science.gov (United States)

    Stricker, Georg; Engelhardt, Alexander; Schulz, Daniel; Schmid, Matthias; Tresch, Achim; Gagneur, Julien

    2017-08-01

    Chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) is a widely used approach to study protein-DNA interactions. Often, the quantities of interest are the differential occupancies relative to controls, between genetic backgrounds, treatments, or combinations thereof. Current methods for differential occupancy of ChIP-Seq data rely however on binning or sliding window techniques, for which the choice of the window and bin sizes are subjective. Here, we present GenoGAM (Genome-wide Generalized Additive Model), which brings the well-established and flexible generalized additive models framework to genomic applications using a data parallelism strategy. We model ChIP-Seq read count frequencies as products of smooth functions along chromosomes. Smoothing parameters are objectively estimated from the data by cross-validation, eliminating ad hoc binning and windowing needed by current approaches. GenoGAM provides base-level and region-level significance testing for full factorial designs. Application to a ChIP-Seq dataset in yeast showed increased sensitivity over existing differential occupancy methods while controlling for type I error rate. By analyzing a set of DNA methylation data and illustrating an extension to a peak caller, we further demonstrate the potential of GenoGAM as a generic statistical modeling tool for genome-wide assays. Software is available from Bioconductor: https://www.bioconductor.org/packages/release/bioc/html/GenoGAM.html . gagneur@in.tum.de. Supplementary information is available at Bioinformatics online.

  2. Parity Symmetry and Parity Breaking in the Quantum Rabi Model with Addition of Ising Interaction

    International Nuclear Information System (INIS)

    Wang Qiong; He Zhi; Yao Chun-Mei

    2015-01-01

    We explore the possibility to generate new parity symmetry in the quantum Rabi model after a bias is introduced. In contrast to a mathematical treatment in a previous publication [J. Phys. A 46 (2013) 265302], we consider a physically realistic method by involving an additional spin into the quantum Rabi model to couple with the original spin by an Ising interaction, and then the parity symmetry is broken as well as the scaling behavior of the ground state by introducing a bias. The rule can be found that the parity symmetry is broken by introducing a bias and then restored by adding new degrees of freedom. Experimental feasibility of realizing the models under discussion is investigated. (paper)

  3. Parenting Styles and Adjustment Outcomes among College Students

    Science.gov (United States)

    Love, Keisha M.; Thomas, Deneia M.

    2014-01-01

    Research has demonstrated that parenting styles partially explain college students' academic adjustment. However, to account for academic adjustment more fully, additional contributors should be identified and tested. We examined the fit of a hypothesized model consisting of parenting styles, indicators of well-being, and academic adjustment…

  4. Testing Departure from Additivity in Tukey’s Model using Shrinkage: Application to a Longitudinal Setting

    Science.gov (United States)

    Ko, Yi-An; Mukherjee, Bhramar; Smith, Jennifer A.; Park, Sung Kyun; Kardia, Sharon L.R.; Allison, Matthew A.; Vokonas, Pantel S.; Chen, Jinbo; Diez-Roux, Ana V.

    2014-01-01

    While there has been extensive research developing gene-environment interaction (GEI) methods in case-control studies, little attention has been given to sparse and efficient modeling of GEI in longitudinal studies. In a two-way table for GEI with rows and columns as categorical variables, a conventional saturated interaction model involves estimation of a specific parameter for each cell, with constraints ensuring identifiability. The estimates are unbiased but are potentially inefficient because the number of parameters to be estimated can grow quickly with increasing categories of row/column factors. On the other hand, Tukey’s one degree of freedom (df) model for non-additivity treats the interaction term as a scaled product of row and column main effects. Due to the parsimonious form of interaction, the interaction estimate leads to enhanced efficiency and the corresponding test could lead to increased power. Unfortunately, Tukey’s model gives biased estimates and low power if the model is misspecified. When screening multiple GEIs where each genetic and environmental marker may exhibit a distinct interaction pattern, a robust estimator for interaction is important for GEI detection. We propose a shrinkage estimator for interaction effects that combines estimates from both Tukey’s and saturated interaction models and use the corresponding Wald test for testing interaction in a longitudinal setting. The proposed estimator is robust to misspecification of interaction structure. We illustrate the proposed methods using two longitudinal studies — the Normative Aging Study and the Multi-Ethnic Study of Atherosclerosis. PMID:25112650

  5. Metabolic modeling of energy balances in Mycoplasma hyopneumoniae shows that pyruvate addition increases growth rate.

    Science.gov (United States)

    Kamminga, Tjerko; Slagman, Simen-Jan; Bijlsma, Jetta J E; Martins Dos Santos, Vitor A P; Suarez-Diez, Maria; Schaap, Peter J

    2017-10-01

    Mycoplasma hyopneumoniae is cultured on large-scale to produce antigen for inactivated whole-cell vaccines against respiratory disease in pigs. However, the fastidious nutrient requirements of this minimal bacterium and the low growth rate make it challenging to reach sufficient biomass yield for antigen production. In this study, we sequenced the genome of M. hyopneumoniae strain 11 and constructed a high quality constraint-based genome-scale metabolic model of 284 chemical reactions and 298 metabolites. We validated the model with time-series data of duplicate fermentation cultures to aim for an integrated model describing the dynamic profiles measured in fermentations. The model predicted that 84% of cellular energy in a standard M. hyopneumoniae cultivation was used for non-growth associated maintenance and only 16% of cellular energy was used for growth and growth associated maintenance. Following a cycle of model-driven experimentation in dedicated fermentation experiments, we were able to increase the fraction of cellular energy used for growth through pyruvate addition to the medium. This increase in turn led to an increase in growth rate and a 2.3 times increase in the total biomass concentration reached after 3-4 days of fermentation, enhancing the productivity of the overall process. The model presented provides a solid basis to understand and further improve M. hyopneumoniae fermentation processes. Biotechnol. Bioeng. 2017;114: 2339-2347. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  6. Modeling Data Containing Outliers using ARIMA Additive Outlier (ARIMA-AO)

    Science.gov (United States)

    Saleh Ahmar, Ansari; Guritno, Suryo; Abdurakhman; Rahman, Abdul; Awi; Alimuddin; Minggi, Ilham; Arif Tiro, M.; Kasim Aidid, M.; Annas, Suwardi; Utami Sutiksno, Dian; Ahmar, Dewi S.; Ahmar, Kurniawan H.; Abqary Ahmar, A.; Zaki, Ahmad; Abdullah, Dahlan; Rahim, Robbi; Nurdiyanto, Heri; Hidayat, Rahmat; Napitupulu, Darmawan; Simarmata, Janner; Kurniasih, Nuning; Andretti Abdillah, Leon; Pranolo, Andri; Haviluddin; Albra, Wahyudin; Arifin, A. Nurani M.

    2018-01-01

    The aim this study is discussed on the detection and correction of data containing the additive outlier (AO) on the model ARIMA (p, d, q). The process of detection and correction of data using an iterative procedure popularized by Box, Jenkins, and Reinsel (1994). By using this method we obtained an ARIMA models were fit to the data containing AO, this model is added to the original model of ARIMA coefficients obtained from the iteration process using regression methods. In the simulation data is obtained that the data contained AO initial models are ARIMA (2,0,0) with MSE = 36,780, after the detection and correction of data obtained by the iteration of the model ARIMA (2,0,0) with the coefficients obtained from the regression Zt = 0,106+0,204Z t‑1+0,401Z t‑2‑329X 1(t)+115X 2(t)+35,9X 3(t) and MSE = 19,365. This shows that there is an improvement of forecasting error rate data.

  7. Hemorrhage-Adjusted Iron Requirements, Hematinics and Hepcidin Define Hereditary Hemorrhagic Telangiectasia as a Model of Hemorrhagic Iron Deficiency

    Science.gov (United States)

    Finnamore, Helen; Le Couteur, James; Hickson, Mary; Busbridge, Mark; Whelan, Kevin; Shovlin, Claire L.

    2013-01-01

    Background Iron deficiency anemia remains a major global health problem. Higher iron demands provide the potential for a targeted preventative approach before anemia develops. The primary study objective was to develop and validate a metric that stratifies recommended dietary iron intake to compensate for patient-specific non-menstrual hemorrhagic losses. The secondary objective was to examine whether iron deficiency can be attributed to under-replacement of epistaxis (nosebleed) hemorrhagic iron losses in hereditary hemorrhagic telangiectasia (HHT). Methodology/Principal Findings The hemorrhage adjusted iron requirement (HAIR) sums the recommended dietary allowance, and iron required to replace additional quantified hemorrhagic losses, based on the pre-menopausal increment to compensate for menstrual losses (formula provided). In a study population of 50 HHT patients completing concurrent dietary and nosebleed questionnaires, 43/50 (86%) met their recommended dietary allowance, but only 10/50 (20%) met their HAIR. Higher HAIR was a powerful predictor of lower hemoglobin (p = 0.009), lower mean corpuscular hemoglobin content (pstopped. Conclusions/significance HAIR values, providing an indication of individuals’ iron requirements, may be a useful tool in prevention, assessment and management of iron deficiency. Iron deficiency in HHT can be explained by under-replacement of nosebleed hemorrhagic iron losses. PMID:24146883

  8. Reduction of carcinogenic 4(5)-methylimidazole in a caramel model system: influence of food additives.

    Science.gov (United States)

    Seo, Seulgi; Ka, Mi-Hyun; Lee, Kwang-Geun

    2014-07-09

    The effect of various food additives on the formation of carcinogenic 4(5)-methylimidazole (4-MI) in a caramel model system was investigated. The relationship between the levels of 4-MI and various pyrazines was studied. When glucose and ammonium hydroxide were heated, the amount of 4-MI was 556 ± 1.3 μg/mL, which increased to 583 ± 2.6 μg/mL by the addition of 0.1 M of sodium sulfite. When various food additives, such as 0.1 M of iron sulfate, magnesium sulfate, zinc sulfate, tryptophan, and cysteine were added, the amount of 4-MI was reduced to 110 ± 0.7, 483 ± 2.0, 460 ± 2.0, 409 ± 4.4, and 397 ± 1.7 μg/mL, respectively. The greatest reduction, 80%, occurred with the addition of iron sulfate. Among the 12 pyrazines, 2-ethyl-6-methylpyrazine with 4-MI showed the highest correlation (r = -0.8239).

  9. Short-wavelength Contractional Structures in Venusian Fold Belts: Additional Constraints From New Models

    Science.gov (United States)

    Ghent, R.; Phillips, R.; Hansen, V.; Nunes, D.

    2002-12-01

    We have previously reported on the development of very short-wavelength (30 km [1, 2]. We simulated the initiation and growth of VST using finite-element models with uniform composition and elasto-visco-plastic rheology undergoing simultaneous cooling and shortening. The models were constrained by Magellan SAR imagery and motivated by the current plume hypothesis for crustal plateau origin [3, 4]. We determined that VST developed only in models with surface temperatures near 1000 K and elevated thermal gradients derived from a halfspace cooling model with initial uniform temperatures of 1200-1400 K. Model rheological profiles indicated a truly viscoplastic character, in which both creep and plastic mechanisms were significant at shallow depths. The resulting topography showed both very short-wavelength components and slightly longer-wavelength, low amplitude folds, as is common in Venusian crustal plateau fold belts. New simulations with greater spatial extent and higher mesh resolution allow further exploration of the interplay between viscous and plastic processes during VST development. Wider models allow more detailed investigation of viscous folding on the 1-4 km scale. We also employ temperature-dependent thermal conductivity [5] to better represent the thermal behavior of the model crust. The additional insight and expanded parameter space provided by these new models allow us to place improved constraints on the early thermal and mechanical evolution of crustal plateaus. [1] Ghent, R.R., R.J. Phillips, V.L. Hansen, and D.C. Nunes, Eos Trans. AGU, 83(19), Spring Meet. Suppl., Abstract P21A-05, 2002. [2] Ghent, R.R., R.J. Phillips, and V.L. Hansen, 2001, Eos Trans. AGU, 82(47), Spring Meet. Suppl., Abstract T41B-0865, 2001. [3] Hansen, V.L. and J.J. Willis, Icarus, 132, 321-343, 1998. [4] Phillips, R.J. and V.L. Hansen, Science, 279, p1492, 1998. [5] Hofmeister, A, Science, 283, p1699, 1999.

  10. Lumped mass model of a 1D metastructure for vibration suppression with no additional mass

    Science.gov (United States)

    Reichl, Katherine K.; Inman, Daniel J.

    2017-09-01

    The article examines the effectiveness of metastructures for vibration suppression from a weight standpoint. Metastructures, a metamaterial inspired concept, are structures with distributed vibration absorbers. In automotive and aerospace industries, it is critical to have low levels of vibrations while also using lightweight materials. Previous work has shown that metastructures are effective at mitigating vibrations, but do not consider the effects of mass. This work takes mass into consideration by comparing a structure with vibration absorbers to a structure of equal mass with no absorbers. These structures are modeled as one-dimensional lumped mass models, chosen for simplicity. Results compare both the steady-state and the transient responses. As a quantitative performance measure, the H2 norm, which is related to the area under the frequency response function, is calculated and compared for both the metastructure and the baseline structure. These results show that it is possible to obtain a favorable vibration response without adding additional mass to the structure. Additionally, the performance measure is utilized to optimize the geometry of the structure, determine the optimal ratio of mass in the absorber to mass of the host structure, and determine the frequencies of the absorbers. The dynamic response of this model is verified using a finite element analysis.

  11. Hemorrhage-adjusted iron requirements, hematinics and hepcidin define hereditary hemorrhagic telangiectasia as a model of hemorrhagic iron deficiency.

    Directory of Open Access Journals (Sweden)

    Helen Finnamore

    Full Text Available Iron deficiency anemia remains a major global health problem. Higher iron demands provide the potential for a targeted preventative approach before anemia develops. The primary study objective was to develop and validate a metric that stratifies recommended dietary iron intake to compensate for patient-specific non-menstrual hemorrhagic losses. The secondary objective was to examine whether iron deficiency can be attributed to under-replacement of epistaxis (nosebleed hemorrhagic iron losses in hereditary hemorrhagic telangiectasia (HHT.The hemorrhage adjusted iron requirement (HAIR sums the recommended dietary allowance, and iron required to replace additional quantified hemorrhagic losses, based on the pre-menopausal increment to compensate for menstrual losses (formula provided. In a study population of 50 HHT patients completing concurrent dietary and nosebleed questionnaires, 43/50 (86% met their recommended dietary allowance, but only 10/50 (20% met their HAIR. Higher HAIR was a powerful predictor of lower hemoglobin (p = 0.009, lower mean corpuscular hemoglobin content (p<0.001, lower log-transformed serum iron (p = 0.009, and higher log-transformed red cell distribution width (p<0.001. There was no evidence of generalised abnormalities in iron handling Ferritin and ferritin(2 explained 60% of the hepcidin variance (p<0.001, and the mean hepcidinferritin ratio was similar to reported controls. Iron supplement use increased the proportion of individuals meeting their HAIR, and blunted associations between HAIR and hematinic indices. Once adjusted for supplement use however, reciprocal relationships between HAIR and hemoglobin/serum iron persisted. Of 568 individuals using iron tablets, most reported problems completing the course. For patients with hereditary hemorrhagic telangiectasia, persistent anemia was reported three-times more frequently if iron tablets caused diarrhea or needed to be stopped.HAIR values, providing an indication of

  12. Delocalization model of regioselectivity and reactivity of free radicals in reactions of addition to olefins

    International Nuclear Information System (INIS)

    Volovik, S.V.; Dyadyusha, G.G.; Staninets, V.I.

    1987-01-01

    On the basis of the concept of polarity (philicity) of free radicals as proposed by the authors, within the framework of methods of qualitative surfaces of potential energy (linear combinations of configurations of fragments) and stabilization energy, an effective model has been developed for the regioselectivity and reactivity of radicals in processes of addition. A critical examination is made of certain key aspects of the change in regiochemistry and reactivity with changes in the electronic structure of the free radical and substrate. The dominant trends in regioselectivity and reactivity in processes of free-radical addition to olefins are controlled by electronic effects and can be predicted by analyzing interactions of diabatic potential energy surfaces or orbital interactions for a system consisting of a free radical and an unsaturated substrate

  13. Effect of Additional Incentives for Aviation Biofuels: Results from the Biomass Scenario Model

    Energy Technology Data Exchange (ETDEWEB)

    Vimmerstedt, Laura J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Newes, Emily K [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-05

    The National Renewable Energy Laboratory supported the Department of Energy, Bioenergy Technologies Office, with analysis of alternative jet fuels in collaboration with the U.S. Department of Transportation, Federal Aviation Administration. Airlines for America requested additional exploratory scenarios within FAA analytic framework. Airlines for America requested additional analysis using the same analytic framework, the Biomass Scenario Model. The results were presented at a public working meeting of the California Air Resources Board on including alternative jet fuel in the Low Carbon Fuel Standard on March 17, 2017 (https://www.arb.ca.gov/fuels/lcfs/lcfs_meetings/lcfs_meetings.htm). This presentation clarifies and annotates the slides from the public working meeting, and provides a link to the full data set. NREL does not advocate for or against the policies analyzed in this study.

  14. Modeling the Flyby Anomalies with Dark Matter Scattering: Update with Additional Data and Further Predictions

    Science.gov (United States)

    Adler, Stephen L.

    2013-06-01

    We continue our exploration of whether the flyby anomalies can be explained by scattering of spacecraft nucleons from dark matter gravitationally bound to the Earth, with the addition of data from five new flybys to that from the original six. We continue to use our model in which inelastic and elastic scatterers populate shells generated by the precession of circular orbits with normals tilted with respect to the Earth's axis. With 11 data points and eight parameters in the model, a statistically meaningful fit is obtained with a chi-squared of 2.7. We give plots of the anomalous acceleration along the spacecraft trajectory, and the cumulative velocity change, for the five flybys which exhibit a significant nonzero anomaly. We also discuss implications of the fit for dark matter-nucleon cross-sections, give the prediction of our fit for the anomaly to be expected from the future Juno flyby, and give predictions of our fit for flyby orbit orientation changes. In addition, we give formulas for estimating the flyby temperature increase caused by dark matter inelastic scattering, and for the fraction of flyby nucleons undergoing such scatters. Finally, for circular satellite orbits, we give a table of predicted secular changes in orbit radius. These are much too large to be reasonable — comparing with data for COBE and GP-B supplied to us by Edward Wright (after the first version of this paper was posted), we find that our model predicts changes in orbit radius that are too large by many orders of magnitude. So the model studied here is ruled out. We conclude that further modeling of the flyby anomalies must simultaneously attempt to fit constraints coming from satellite orbits.

  15. Topsoil organic carbon content of Europe, a new map based on a generalised additive model

    Science.gov (United States)

    de Brogniez, Delphine; Ballabio, Cristiano; Stevens, Antoine; Jones, Robert J. A.; Montanarella, Luca; van Wesemael, Bas

    2014-05-01

    There is an increasing demand for up-to-date spatially continuous organic carbon (OC) data for global environment and climatic modeling. Whilst the current map of topsoil organic carbon content for Europe (Jones et al., 2005) was produced by applying expert-knowledge based pedo-transfer rules on large soil mapping units, the aim of this study was to replace it by applying digital soil mapping techniques on the first European harmonised geo-referenced topsoil (0-20 cm) database, which arises from the LUCAS (land use/cover area frame statistical survey) survey. A generalized additive model (GAM) was calibrated on 85% of the dataset (ca. 17 000 soil samples) and a backward stepwise approach selected slope, land cover, temperature, net primary productivity, latitude and longitude as environmental covariates (500 m resolution). The validation of the model (applied on 15% of the dataset), gave an R2 of 0.27. We observed that most organic soils were under-predicted by the model and that soils of Scandinavia were also poorly predicted. The model showed an RMSE of 42 g kg-1 for mineral soils and of 287 g kg-1 for organic soils. The map of predicted OC content showed the lowest values in Mediterranean countries and in croplands across Europe, whereas highest OC content were predicted in wetlands, woodlands and in mountainous areas. The map of standard error of the OC model predictions showed high values in northern latitudes, wetlands, moors and heathlands, whereas low uncertainty was mostly found in croplands. A comparison of our results with the map of Jones et al. (2005) showed a general agreement on the prediction of mineral soils' OC content, most probably because the models use some common covariates, namely land cover and temperature. Our model however failed to predict values of OC content greater than 200 g kg-1, which we explain by the imposed unimodal distribution of our model, whose mean is tilted towards the majority of soils, which are mineral. Finally, average

  16. Improving the predictive accuracy of hurricane power outage forecasts using generalized additive models.

    Science.gov (United States)

    Han, Seung-Ryong; Guikema, Seth D; Quiring, Steven M

    2009-10-01

    Electric power is a critical infrastructure service after hurricanes, and rapid restoration of electric power is important in order to minimize losses in the impacted areas. However, rapid restoration of electric power after a hurricane depends on obtaining the necessary resources, primarily repair crews and materials, before the hurricane makes landfall and then appropriately deploying these resources as soon as possible after the hurricane. This, in turn, depends on having sound estimates of both the overall severity of the storm and the relative risk of power outages in different areas. Past studies have developed statistical, regression-based approaches for estimating the number of power outages in advance of an approaching hurricane. However, these approaches have either not been applicable for future events or have had lower predictive accuracy than desired. This article shows that a different type of regression model, a generalized additive model (GAM), can outperform the types of models used previously. This is done by developing and validating a GAM based on power outage data during past hurricanes in the Gulf Coast region and comparing the results from this model to the previously used generalized linear models.

  17. Using additive and coupled spatiotemporal SPDE models: a flexible illustration for predicting occurrence of Culicoides species.

    Science.gov (United States)

    Kifle, Yimer Wasihun; Hens, Niel; Faes, Christel

    2017-11-01

    This paper formulates and compares a general class of spatiotemporal models for univariate space-time geostatistical data. The implementation of stochastic partial differential equation (SPDE) approach combined with integrated nested Laplace approximation into the R-INLA package makes it computationally feasible to use spatiotemporal models. However, the impact of specifying models with and without space-time interaction is unclear. We formulate an extensive class of additive and coupled spatiotemporal SPDE models and investigate the distinction between them by (1) Extending their temporal effect, allowing a random walk process in time, (2) varying the spatial correlation function and (3) running a simulation study to assess the effect of misspecifying the spatial and temporal models, and to assess the generalizability of our results to a higher number of locations. Our methods are illustrated with Culicoides data from Belgium. The Bayesian spatial predictions showed that the highest prevalence of Culicoides species was found in the Northeastern and central parts of Belgium during summer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Mixed butanols addition to gasoline surrogates: Shock tube ignition delay time measurements and chemical kinetic modeling

    KAUST Repository

    AlRamadan, Abdullah S.

    2015-10-01

    The demand for fuels with high anti-knock quality has historically been rising, and will continue to increase with the development of downsized and turbocharged spark-ignition engines. Butanol isomers, such as 2-butanol and tert-butanol, have high octane ratings (RON of 105 and 107, respectively), and thus mixed butanols (68.8% by volume of 2-butanol and 31.2% by volume of tert-butanol) can be added to the conventional petroleum-derived gasoline fuels to improve octane performance. In the present work, the effect of mixed butanols addition to gasoline surrogates has been investigated in a high-pressure shock tube facility. The ignition delay times of mixed butanols stoichiometric mixtures were measured at 20 and 40bar over a temperature range of 800-1200K. Next, 10vol% and 20vol% of mixed butanols (MB) were blended with two different toluene/n-heptane/iso-octane (TPRF) fuel blends having octane ratings of RON 90/MON 81.7 and RON 84.6/MON 79.3. These MB/TPRF mixtures were investigated in the shock tube conditions similar to those mentioned above. A chemical kinetic model was developed to simulate the low- and high-temperature oxidation of mixed butanols and MB/TPRF blends. The proposed model is in good agreement with the experimental data with some deviations at low temperatures. The effect of mixed butanols addition to TPRFs is marginal when examining the ignition delay times at high temperatures. However, when extended to lower temperatures (T < 850K), the model shows that the mixed butanols addition to TPRFs causes the ignition delay times to increase and hence behaves like an octane booster at engine-like conditions. © 2015 The Combustion Institute.

  19. Development of bovine serum albumin-water partition coefficients predictive models for ionogenic organic chemicals based on chemical form adjusted descriptors.

    Science.gov (United States)

    Ding, Feng; Yang, Xianhai; Chen, Guosong; Liu, Jining; Shi, Lili; Chen, Jingwen

    2017-10-01

    The partition coefficients between bovine serum albumin (BSA) and water (K BSA/w ) for ionogenic organic chemicals (IOCs) were different greatly from those of neutral organic chemicals (NOCs). For NOCs, several excellent models were developed to predict their logK BSA/w . However, it was found that the conventional descriptors are inappropriate for modeling logK BSA/w of IOCs. Thus, alternative approaches are urgently needed to develop predictive models for K BSA/w of IOCs. In this study, molecular descriptors that can be used to characterize the ionization effects (e.g. chemical form adjusted descriptors) were calculated and used to develop predictive models for logK BSA/w of IOCs. The models developed had high goodness-of-fit, robustness, and predictive ability. The predictor variables selected to construct the models included the chemical form adjusted averages of the negative potentials on the molecular surface (V s-adj - ), the chemical form adjusted molecular dipole moment (dipolemoment adj ), the logarithm of the n-octanol/water distribution coefficient (logD). As these molecular descriptors can be calculated from their molecular structures directly, the developed model can be easily used to fill the logK BSA/w data gap for other IOCs within the applicability domain. Furthermore, the chemical form adjusted descriptors calculated in this study also could be used to construct predictive models on other endpoints of IOCs. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Applying the Transactional Stress and Coping Model to Sickle Cell Disorder and Insulin-Dependent Diabetes Mellitus: Identifying Psychosocial Variables Related to Adjustment and Intervention

    Science.gov (United States)

    Hocking, Matthew C.; Lochman, John E.

    2005-01-01

    This review paper examines the literature on psychosocial factors associated with adjustment to sickle cell disease and insulin-dependent diabetes mellitus in children through the framework of the transactional stress and coping (TSC) model. The transactional stress and coping model views adaptation to a childhood chronic illness as mediated by…

  1. Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Jack Istok; Melora Park; James McKinley; Chongxuan Liu; Lee Krumholz; Anne Spain; Aaron Peacock; Brett Baldwin

    2007-04-19

    The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on microbial growth, community composition and system geochemistry. The hypothesis is that a thermodynamic analysis of the energy-yielding growth reactions performed by defined groups of microorganisms can be used to make quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change.

  2. Additional Model Datasets and Results to Accelerate the Verification and Validation of RELAP-7

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jun Soo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Choi, Yong Joon [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-11-01

    The RELAP-7 code verification and validation activities are ongoing under the code assessment plan proposed in the previous document (INL-EXT-16-40015). Among the list of V&V test problems in the ‘RELAP-7 code V&V RTM (Requirements Traceability Matrix)’, the RELAP-7 7-equation model has been tested with additional demonstration problems and the results of these tests are reported in this document. In this report, we describe the testing process, the test cases that were conducted, and the results of the evaluation.

  3. Real-time slicing algorithm for Stereolithography (STL) CAD model applied in additive manufacturing industry

    Science.gov (United States)

    Adnan, F. A.; Romlay, F. R. M.; Shafiq, M.

    2018-04-01

    Owing to the advent of the industrial revolution 4.0, the need for further evaluating processes applied in the additive manufacturing application particularly the computational process for slicing is non-trivial. This paper evaluates a real-time slicing algorithm for slicing an STL formatted computer-aided design (CAD). A line-plane intersection equation was applied to perform the slicing procedure at any given height. The application of this algorithm has found to provide a better computational time regardless the number of facet in the STL model. The performance of this algorithm is evaluated by comparing the results of the computational time for different geometry.

  4. Optimization of Grignard Addition to Esters: Kinetic and Mechanistic Study of Model Phthalide using Flow Chemistry

    DEFF Research Database (Denmark)

    Pedersen, Michael J.; Born, Stephen; Neuenschwander, Ulrich

    2018-01-01

    The kinetics of sequential addition of a distinct Grignard species onto a lactone is studied by flow chemistry. The experimental data are shown to be consistent with a kinetic model based on four reaction steps, reaction of ester to magnesium hemiacetal, rearrangement to ketone (forward...... and backward) and reaction of ketone to tertiary alcohol upon quenching. The experimental derived reaction mechanism is supported by ab initio molecular computations, and the predicted activation energy is in good agreement with the experimental observations. The Grignard reaction follows a substrate...

  5. Assessing the effect, on animal model, of mixture of food additives, on the water balance.

    Science.gov (United States)

    Friedrich, Mariola; Kuchlewska, Magdalena

    2013-01-01

    The purpose of this study was to determine, on the animal model, the effect of modification of diet composition and administration of selected food additives on water balance in the body. The study was conducted with 48 males and 48 females (separately for each sex) of Wistar strain rats divided into four groups. For drinking, the animals from groups I and III were receiving water, whereas the animals from groups II and IV were administered 5 ml of a solution of selected food additives (potassium nitrate - E 252, sodium nitrite - E 250, benzoic acid - E 210, sorbic acid - E 200, and monosodium glutamate - E 621). Doses of the administered food additives were computed taking into account the average intake by men, expressed per body mass unit. Having drunk the solution, the animals were provided water for drinking. The mixture of selected food additives applied in the experiment was found to facilitate water retention in the body both in the case of both male and female rats, and differences observed between the volume of ingested fluids and the volume of excreted urine were statistically significant in the animals fed the basal diet. The type of feed mixture provided to the animals affected the site of water retention - in the case of animals receiving the basal diet analyses demonstrated a significant increase in water content in the liver tissue, whereas in the animals fed the modified diet water was observed to accumulate in the vascular bed. Taking into account the fact of water retention in the vascular bed, the effects of food additives intake may be more adverse in the case of females.

  6. Evaluation of 3D Additively Manufactured Canine Brain Models for Teaching Veterinary Neuroanatomy.

    Science.gov (United States)

    Schoenfeld-Tacher, Regina M; Horn, Timothy J; Scheviak, Tyler A; Royal, Kenneth D; Hudson, Lola C

    Physical specimens are essential to the teaching of veterinary anatomy. While fresh and fixed cadavers have long been the medium of choice, plastinated specimens have gained widespread acceptance as adjuncts to dissection materials. Even though the plastination process increases the durability of specimens, these are still derived from animal tissues and require periodic replacement if used by students on a regular basis. This study investigated the use of three-dimensional additively manufactured (3D AM) models (colloquially referred to as 3D-printed models) of the canine brain as a replacement for plastinated or formalin-fixed brains. The models investigated were built based on a micro-MRI of a single canine brain and have numerous practical advantages, such as durability, lower cost over time, and reduction of animal use. The effectiveness of the models was assessed by comparing performance among students who were instructed using either plastinated brains or 3D AM models. This study used propensity score matching to generate similar pairs of students. Pairings were based on gender and initial anatomy performance across two consecutive classes of first-year veterinary students. Students' performance on a practical neuroanatomy exam was compared, and no significant differences were found in scores based on the type of material (3D AM models or plastinated specimens) used for instruction. Students in both groups were equally able to identify neuroanatomical structures on cadaveric material, as well as respond to questions involving application of neuroanatomy knowledge. Therefore, we postulate that 3D AM canine brain models are an acceptable alternative to plastinated specimens in teaching veterinary neuroanatomy.

  7. Kriging modeling and SPSA adjusting PID with KPWF compensator control of IPMC gripper for mm-sized objects

    Science.gov (United States)

    Chen, Yang; Hao, Lina; Yang, Hui; Gao, Jinhai

    2017-12-01

    Ionic polymer metal composite (IPMC) as a new smart material has been widely concerned in the micromanipulation field. In this paper, a novel two-finger gripper which contains an IPMC actuator and an ultrasensitive force sensor is proposed and fabricated. The IPMC as one finger of the gripper for mm-sized objects can achieve gripping and releasing motion, and the other finger works not only as a support finger but also as a force sensor. Because of the feedback signal of the force sensor, this integrated actuating and sensing gripper can complete gripping miniature objects in millimeter scale. The Kriging model is used to describe nonlinear characteristics of the IPMC for the first time, and then the control scheme called simultaneous perturbation stochastic approximation adjusting a proportion integration differentiation parameter controller with a Kriging predictor wavelet filter compensator is applied to track the gripping force of the gripper. The high precision force tracking in the foam ball manipulation process is obtained on a semi-physical experimental platform, which demonstrates that this gripper for mm-sized objects can work well in manipulation applications.

  8. Hybrid 2D-3D modelling of GTA welding with filler wire addition

    KAUST Repository

    Traidia, Abderrazak

    2012-07-01

    A hybrid 2D-3D model for the numerical simulation of Gas Tungsten Arc welding is proposed in this paper. It offers the possibility to predict the temperature field as well as the shape of the solidified weld joint for different operating parameters, with relatively good accuracy and reasonable computational cost. Also, an original approach to simulate the effect of immersing a cold filler wire in the weld pool is presented. The simulation results reveal two important observations. First, the weld pool depth is locally decreased in the presence of filler metal, which is due to the energy absorption by the cold feeding wire from the hot molten pool. In addition, the weld shape, maximum temperature and thermal cycles in the workpiece are relatively well predicted even when a 2D model for the arc plasma region is used. © 2012 Elsevier Ltd. All rights reserved.

  9. The Influence of Non-linear 3-D Mantle Rheology on Predictions of Glacial Isostatic Adjustment Models

    Science.gov (United States)

    Van Der Wal, W.; Barnhoorn, A.; Stocchi, P.; Drury, M. R.; Wu, P. P.; Vermeersen, B. L.

    2011-12-01

    Ice melting in Greenland and Antarctica can be estimated from GRACE satellite measurements. The largest source of error in these estimates is uncertainty in models for Glacial Isostatic Adjustment (GIA). GIA models that are used to correct the GRACE data have several shortcomings, including (i) mantle viscosity is only varied with depth, and (ii) stress-dependence of viscosity is ignored. Here we attempt to improve on these two issues with the ultimate goal of providing more realistic GIA predictions in areas that are currently ice covered. The improved model is first tested against observations in Fennoscandia, where there is good coverage with GIA observations, before applying it to Greenland. Deformation laws for diffusion and dislocation creep in olivine are taken from a compilation of laboratory experiments. Temperature is obtained from two different sources: surface heatflow maps as input for the heat transfer equation, and seismic velocity anomalies converted to upper mantle temperatures. Grain size and olivine water content are kept as free parameters. Surface loading is provided by an ice loading history that is constructed from constraints on past ice margins and input from climatology. The finite element model includes self-gravitation but not compressibility and background stresses. It is found that the viscosity in Fennoscandia changes in time by two orders of magnitude for a wet rheology with large grain size. The wet rheology provides the best fit to historic sea level data. However, present-day uplift and gravity rates are too low for such a rheology. We apply a wet rheology on Greenland, and simulate a Little Ice Age (LIA) increase in thickness on top of the ICE-5G ice loading history. Preliminary results show a negative geoid rate of magnitude more than 0.5 mm/year due to the LIA increase in ice thickness in combination with the non-linear upper mantle rheology. More tests are necessary to determine the influence of mantle rheology on GIA model

  10. Quantifying spatial disparities in neonatal mortality using a structured additive regression model.

    Directory of Open Access Journals (Sweden)

    Lawrence N Kazembe

    Full Text Available BACKGROUND: Neonatal mortality contributes a large proportion towards early childhood mortality in developing countries, with considerable geographical variation at small areas within countries. METHODS: A geo-additive logistic regression model is proposed for quantifying small-scale geographical variation in neonatal mortality, and to estimate risk factors of neonatal mortality. Random effects are introduced to capture spatial correlation and heterogeneity. The spatial correlation can be modelled using the Markov random fields (MRF when data is aggregated, while the two dimensional P-splines apply when exact locations are available, whereas the unstructured spatial effects are assigned an independent Gaussian prior. Socio-economic and bio-demographic factors which may affect the risk of neonatal mortality are simultaneously estimated as fixed effects and as nonlinear effects for continuous covariates. The smooth effects of continuous covariates are modelled by second-order random walk priors. Modelling and inference use the empirical Bayesian approach via penalized likelihood technique. The methodology is applied to analyse the likelihood of neonatal deaths, using data from the 2000 Malawi demographic and health survey. The spatial effects are quantified through MRF and two dimensional P-splines priors. RESULTS: Findings indicate that both fixed and spatial effects are associated with neonatal mortality. CONCLUSIONS: Our study, therefore, suggests that the challenge to reduce neonatal mortality goes beyond addressing individual factors, but also require to understanding unmeasured covariates for potential effective interventions.

  11. Guarana Provides Additional Stimulation over Caffeine Alone in the Planarian Model

    Science.gov (United States)

    Moustakas, Dimitrios; Mezzio, Michael; Rodriguez, Branden R.; Constable, Mic Andre; Mulligan, Margaret E.; Voura, Evelyn B.

    2015-01-01

    The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose. PMID:25880065

  12. Guarana provides additional stimulation over caffeine alone in the planarian model.

    Directory of Open Access Journals (Sweden)

    Dimitrios Moustakas

    Full Text Available The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose.

  13. Bioadhesive agents in addition to oral contrast media - evaluation in an animal model

    International Nuclear Information System (INIS)

    Conrad, R.; Schneider, G.; Textor, J.; Schild, H.H.; Fimmers, R.

    1998-01-01

    Purpose: To evaluate the additional effect of bioadhesives in combination with iotrolan and barium as oral contrast media in an animal model. Method: The bioadhesives Noveon, CMC, Tylose and Carbopol 934 were added to iotrolan and barium. The solutions were administered to rabbits by a feeding tube. The animals were investigated by computed tomography (CT) and radiography after 0,5, 4, 12, 24 and in part after 48 hours. Mucosal coating and contrast filling of the bowel were evaluated. Results: Addition of bioadhesives to oral contrast media effected long-term contrast in the small intestine and colon, but no improvement in continuous filling and coating of the gastrointestinal tract was detected. Mucosal coating was seen only in short regions of the caecum and small intestine. In CT the best results for coating were observed with tylose and CMC, in radiography additionally with carbopol and noveon. All contrast medium solutions were well tolerated. Conclusion: The evaluated contrast medium solutions with bioadhesives have shown long-term contrast but no improvement in coating in comparison to conventional oral contrast media. (orig.) [de

  14. A Model to Predict Psychological- and Health-Related Adjustment in Men with Prostate Cancer: The Role of Post Traumatic Growth, Physical Post Traumatic Growth, Resilience and Mindfulness.

    Science.gov (United States)

    Walsh, Deirdre M J; Morrison, Todd G; Conway, Ronan J; Rogers, Eamonn; Sullivan, Francis J; Groarke, AnnMarie

    2018-01-01

    Background: Post traumatic growth (PTG) can be defined as positive change following a traumatic event. The current conceptualization of PTG encompasses five main dimensions, however, there is no dimension which accounts for the distinct effect of a physical trauma on PTG. The purpose of the present research was to test the role of PTG, physical post traumatic growth (PPTG), resilience and mindfulness in predicting psychological and health related adjustment. Method: Ethical approval was obtained from relevant institutional ethics committees. Participants ( N = 241), who were at least 1 year post prostate cancer treatment, were invited to complete a battery of questionnaires either through an online survey or a paper and pencil package received in the post The sample ranged in age from 44 to 88 years ( M = 64.02, SD = 7.76). Data were analysis using confirmatory factor analysis and structural equation modeling. Results: The physical post traumatic growth inventory (P-PTGI) was used to evaluate the role of PPTG in predicting adjustment using structural equation modeling. P-PTGI predicted lower distress and improvement of quality of life, whereas conversely, the traditional PTG measure was linked with poor adjustment. The relationship between resilience and adjustment was found to be mediated by P-PTGI. Conclusion: Findings suggest the central role of PTG in the prostate cancer survivorship experience is enhanced by the inclusion of PPTG. Adjusting to a physical trauma such as illness (internal transgressor) is unlike a trauma with an external transgressor as the physical trauma creates an entirely different framework for adjustment. The current study demonstrates the impact of PPTG on adjustment. This significantly adds to the theory of the development of PTG by highlighting the interplay of resilience with PTG, PPTG, and adjustment.

  15. A Model to Predict Psychological- and Health-Related Adjustment in Men with Prostate Cancer: The Role of Post Traumatic Growth, Physical Post Traumatic Growth, Resilience and Mindfulness

    Directory of Open Access Journals (Sweden)

    Deirdre M. J. Walsh

    2018-02-01

    Full Text Available Background: Post traumatic growth (PTG can be defined as positive change following a traumatic event. The current conceptualization of PTG encompasses five main dimensions, however, there is no dimension which accounts for the distinct effect of a physical trauma on PTG. The purpose of the present research was to test the role of PTG, physical post traumatic growth (PPTG, resilience and mindfulness in predicting psychological and health related adjustment.Method: Ethical approval was obtained from relevant institutional ethics committees. Participants (N = 241, who were at least 1 year post prostate cancer treatment, were invited to complete a battery of questionnaires either through an online survey or a paper and pencil package received in the post The sample ranged in age from 44 to 88 years (M = 64.02, SD = 7.76. Data were analysis using confirmatory factor analysis and structural equation modeling.Results: The physical post traumatic growth inventory (P-PTGI was used to evaluate the role of PPTG in predicting adjustment using structural equation modeling. P-PTGI predicted lower distress and improvement of quality of life, whereas conversely, the traditional PTG measure was linked with poor adjustment. The relationship between resilience and adjustment was found to be mediated by P-PTGI.Conclusion: Findings suggest the central role of PTG in the prostate cancer survivorship experience is enhanced by the inclusion of PPTG. Adjusting to a physical trauma such as illness (internal transgressor is unlike a trauma with an external transgressor as the physical trauma creates an entirely different framework for adjustment. The current study demonstrates the impact of PPTG on adjustment. This significantly adds to the theory of the development of PTG by highlighting the interplay of resilience with PTG, PPTG, and adjustment.

  16. Generalized additive models used to predict species abundance in the Gulf of Mexico: an ecosystem modeling tool.

    Directory of Open Access Journals (Sweden)

    Michael Drexler

    Full Text Available Spatially explicit ecosystem models of all types require an initial allocation of biomass, often in areas where fisheries independent abundance estimates do not exist. A generalized additive modelling (GAM approach is used to describe the abundance of 40 species groups (i.e. functional groups across the Gulf of Mexico (GoM using a large fisheries independent data set (SEAMAP and climate scale oceanographic conditions. Predictor variables included in the model are chlorophyll a, sediment type, dissolved oxygen, temperature, and depth. Despite the presence of a large number of zeros in the data, a single GAM using a negative binomial distribution was suitable to make predictions of abundance for multiple functional groups. We present an example case study using pink shrimp (Farfantepenaeus duroarum and compare the results to known distributions. The model successfully predicts the known areas of high abundance in the GoM, including those areas where no data was inputted into the model fitting. Overall, the model reliably captures areas of high and low abundance for the large majority of functional groups observed in SEAMAP. The result of this method allows for the objective setting of spatial distributions for numerous functional groups across a modeling domain, even where abundance data may not exist.

  17. Computational and Mathematical Model with Phase Change and Metal Addition Applied to GMAW

    Directory of Open Access Journals (Sweden)

    Alfredo dos Santos Maia Neto

    2017-01-01

    Full Text Available This work presents a 3D computational/mathematical model to solve the heat diffusion equation with phase change, considering metal addition, complex geometry, and thermal properties varying with temperature. The finite volume method was used and the computational code was implemented in C++, using a Borland compiler. Experimental tests considering workpieces of stainless steel AISI 304 were carried out for validation of the thermal model. Inverse techniques based on Golden Section method were used to estimate the heat transfer rate to the workpieces. Experimental temperatures were measured using thermocouples type J—in a total of 07 (seven—all connected to the welded workpiece and the Agilent 34970A data logger. The workpieces were chamfered in a 45° V-groove in which liquid metal was added on only one weld pass. An innovation presented in this work when compared to other works in scientific literature was the geometry of the weld pool. The good relation between experimental and simulated data confirmed the quality and robustness of the thermal model proposed in this work.

  18. Modeling additional solar constraints on a human being inside a room

    Energy Technology Data Exchange (ETDEWEB)

    Thellier, Francoise; Monchoux, Francoise; Bonnis-Sassi, Michel; Lartigue, Berengere [Laboratoire Physique de l' Homme Appliquee a Son Environnement (PHASE), Universite Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex 9 (France)

    2008-04-15

    Sun fluxes induce additional heterogeneous thermal constraints in buildings and may also lead to discomfort for the inhabitant. To calculate the local thermal sensation of a human being totally or partially situated in the sunlight, the solar radiation inside a room and its detailed distribution on parts of the human body are modeled. The present study focuses on the solar gains part of a complete modeling tool simulating an occupied building. The irradiated areas are calculated with a ray tracing method taking shadow into account. Solar fluxes are computed. Fluxes can be absorbed by each surface or reflected. The reflected fluxes are then absorbed at the next impact. A multi-node thermoregulation model (MARCL) represents the thermal behavior of the human body and all its heat exchanges with the environment. The thermal transient simulation of the whole occupied building is performed in TRNSYS simulation software. In the case presented here, the results show that, when a person is inside the building, the skin and clothing temperatures of the irradiated segments increase more or less depending on the segments but the global thermal equilibrium of the body is maintained thanks to strong physiological reactions. (author)

  19. Distributional modeling and short-term forecasting of electricity prices by Generalized Additive Models for Location, Scale and Shape

    International Nuclear Information System (INIS)

    Serinaldi, Francesco

    2011-01-01

    In the context of the liberalized and deregulated electricity markets, price forecasting has become increasingly important for energy company's plans and market strategies. Within the class of the time series models that are used to perform price forecasting, the subclasses of methods based on stochastic time series and causal models commonly provide point forecasts, whereas the corresponding uncertainty is quantified by approximate or simulation-based confidence intervals. Aiming to improve the uncertainty assessment, this study introduces the Generalized Additive Models for Location, Scale and Shape (GAMLSS) to model the dynamically varying distribution of prices. The GAMLSS allow fitting a variety of distributions whose parameters change according to covariates via a number of linear and nonlinear relationships. In this way, price periodicities, trends and abrupt changes characterizing both the position parameter (linked to the expected value of prices), and the scale and shape parameters (related to price volatility, skewness, and kurtosis) can be explicitly incorporated in the model setup. Relying on the past behavior of the prices and exogenous variables, the GAMLSS enable the short-term (one-day ahead) forecast of the entire distribution of prices. The approach was tested on two datasets from the widely studied California Power Exchange (CalPX) market, and the less mature Italian Power Exchange (IPEX). CalPX data allow comparing the GAMLSS forecasting performance with published results obtained by different models. The study points out that the GAMLSS framework can be a flexible alternative to several linear and nonlinear stochastic models. - Research Highlights: ► Generalized Additive Models for Location, Scale and Shape (GAMLSS) are used to model electricity prices' time series. ► GAMLSS provide the entire dynamicaly varying distribution function of prices resorting to a suitable set of covariates that drive the instantaneous values of the parameters

  20. Modeling the flux of metabolites in the juvenile hormone biosynthesis pathway using generalized additive models and ordinary differential equations.

    Directory of Open Access Journals (Sweden)

    Raúl O Martínez-Rincón

    Full Text Available Juvenile hormone (JH regulates development and reproductive maturation in insects. The corpora allata (CA from female adult mosquitoes synthesize fluctuating levels of JH, which have been linked to the ovarian development and are influenced by nutritional signals. The rate of JH biosynthesis is controlled by the rate of flux of isoprenoids in the pathway, which is the outcome of a complex interplay of changes in precursor pools and enzyme levels. A comprehensive study of the changes in enzymatic activities and precursor pool sizes have been previously reported for the mosquito Aedes aegypti JH biosynthesis pathway. In the present studies, we used two different quantitative approaches to describe and predict how changes in the individual metabolic reactions in the pathway affect JH synthesis. First, we constructed generalized additive models (GAMs that described the association between changes in specific metabolite concentrations with changes in enzymatic activities and substrate concentrations. Changes in substrate concentrations explained 50% or more of the model deviances in 7 of the 13 metabolic steps analyzed. Addition of information on enzymatic activities almost always improved the fitness of GAMs built solely based on substrate concentrations. GAMs were validated using experimental data that were not included when the model was built. In addition, a system of ordinary differential equations (ODE was developed to describe the instantaneous changes in metabolites as a function of the levels of enzymatic catalytic activities. The results demonstrated the ability of the models to predict changes in the flux of metabolites in the JH pathway, and can be used in the future to design and validate experimental manipulations of JH synthesis.

  1. Worst case prediction of additives migration from polystyrene for food safety purposes: a model update.

    Science.gov (United States)

    Martínez-López, Brais; Gontard, Nathalie; Peyron, Stéphane

    2018-03-01

    A reliable prediction of migration levels of plastic additives into food requires a robust estimation of diffusivity. Predictive modelling of diffusivity as recommended by the EU commission is carried out using a semi-empirical equation that relies on two polymer-dependent parameters. These parameters were determined for the polymers most used by packaging industry (LLDPE, HDPE, PP, PET, PS, HIPS) from the diffusivity data available at that time. In the specific case of general purpose polystyrene, the diffusivity data published since then shows that the use of the equation with the original parameters results in systematic underestimation of diffusivity. The goal of this study was therefore, to propose an update of the aforementioned parameters for PS on the basis of up to date diffusivity data, so the equation can be used for a reasoned overestimation of diffusivity.

  2. Additive Manufacturing of PLA and CF/PLA Binding Layer Specimens via Fused Deposition Modeling

    Science.gov (United States)

    Li, Yuhang; Gao, Shiyou; Dong, Rongmei; Ding, Xuebing; Duan, Xiaoxi

    2018-02-01

    As one of the most popular additive manufacturing techniques, fused deposition modeling (FDM) is successfully applied in aerospace, automotive, architecture, and other fields to fabricate thermoplastic parts. Unfortunately, as a result of the limited nature of the mechanical properties and mass in raw materials, there is a pressing need to improve mechanical properties and reduce weight for FDM parts. Therefore, this paper presents an experiment of a special polylactic acid (PLA) and carbon fiber (CF)/PLA-laminated experimental specimen fabricated using the FDM process. The mechanical properties and mass analysis of the new composites for the PLA and CF/PLA binding layer specimen are investigated experimentally. Through the experimental analysis, one can conclude that the mass of laminated specimen is lighter than the CF/PLA specimen, and the tensile and flexural mechanical properties are higher than the pure PLA specimen.

  3. Additive Manufacturing of PLA and CF/PLA Binding Layer Specimens via Fused Deposition Modeling

    Science.gov (United States)

    Li, Yuhang; Gao, Shiyou; Dong, Rongmei; Ding, Xuebing; Duan, Xiaoxi

    2018-01-01

    As one of the most popular additive manufacturing techniques, fused deposition modeling (FDM) is successfully applied in aerospace, automotive, architecture, and other fields to fabricate thermoplastic parts. Unfortunately, as a result of the limited nature of the mechanical properties and mass in raw materials, there is a pressing need to improve mechanical properties and reduce weight for FDM parts. Therefore, this paper presents an experiment of a special polylactic acid (PLA) and carbon fiber (CF)/PLA-laminated experimental specimen fabricated using the FDM process. The mechanical properties and mass analysis of the new composites for the PLA and CF/PLA binding layer specimen are investigated experimentally. Through the experimental analysis, one can conclude that the mass of laminated specimen is lighter than the CF/PLA specimen, and the tensile and flexural mechanical properties are higher than the pure PLA specimen.

  4. Characterization of metal additive manufacturing surfaces using synchrotron X-ray CT and micromechanical modeling

    Science.gov (United States)

    Kantzos, C. A.; Cunningham, R. W.; Tari, V.; Rollett, A. D.

    2017-12-01

    Characterizing complex surface topologies is necessary to understand stress concentrations created by rough surfaces, particularly those made via laser power-bed additive manufacturing (AM). Synchrotron-based X-ray microtomography (μ XCT ) of AM surfaces was shown to provide high resolution detail of surface features and near-surface porosity. Using the CT reconstructions to instantiate a micromechanical model indicated that surface notches and near-surface porosity both act as stress concentrators, while adhered powder carried little to no load. Differences in powder size distribution had no direct effect on the relevant surface features, nor on stress concentrations. Conventional measurements of surface roughness, which are highly influenced by adhered powder, are therefore unlikely to contain the information relevant to damage accumulation and crack initiation.

  5. Reinnervated Split-Muscle Technique for Creating Additional Myoelectric Sites in an Animal Model.

    Science.gov (United States)

    Deslivia, Maria Florencia; Lee, Hyun-Joo; Zulkarnain, Rizki Fajar; Zhu, Bin; Adikrishna, Arnold; Jeon, In-Ho; Kim, Keehoon

    2016-12-01

    This study proposes a novel reinnervated split-muscle operation to create additional myoelectric sites as sources of command signals of myoelectric prostheses for enhanced dexterous hand-to-wrist motions. The aim of this study was to investigate the postprocedure electromyographic properties of the muscles as distinct myoelectric sites in a rat model. The reinnervated split-muscle group (n = 6) had the gastrocnemius muscle separated along its longitudinal axis and nerves transferred to each new muscle (peroneal nerve to lateral muscle head and tibial to medial one); the non-split-muscle group (n = 6) only had nerve transfers with its muscle intact. Functional testing was conducted after 10 weeks. The main parameter is the difference in mean electromyographic amplitude between the new muscles, with greater values indicating better separability. After the reinnervated split-muscle procedure, there is a significant increase of the average ratio between two muscles compared with the control group, from 0.44 (range, 0.02 to 0.86) to 0.77 (range, 0.35 to 0.98) (p = 0.011). In addition, compared with the non-split muscle group, nerve transfer in the split-muscle group is more successful in reaching its intended target muscle. A reinnervated split-muscle procedure could be beneficial for acquiring a more precise and discrete command signal in upper limb amputees, thus enabling the creation of more dexterous prosthetic arm.

  6. Modelling and Design of HF RFID Passive Transponders with Additional Energy Harvester

    Directory of Open Access Journals (Sweden)

    Piotr Jankowski-Mihułowicz

    2013-01-01

    Full Text Available The huge progress in electronics technology and RFID technique gives the opportunity to implement additional features in transponders. It should be noted that either passive or semipassive transponders are supplied with energy that is derived from the electromagnetic field generated by the read/write device and its antenna. This power source is used to conduct radio-communication process and excess energy could be used to power the extra electronic circuits, but the problem is to determine the additional power load impact on the RFID system proper operation and size of interrogation zone. The ability to power the supplementary electronic blocks applied in the HF passive transponders is discussed in detail this paper. The simulation model and test samples with a harvester that recovers energy from the electromagnetic field of read/write device and its antenna have been developed in order to conduct investigations. The harvested energy has been utilized to supply a microprocessor acquisition block for LTCC pressure sensor developed in research previously described by authors.

  7. Aggregation of gluten proteins in model dough after fibre polysaccharide addition.

    Science.gov (United States)

    Nawrocka, Agnieszka; Szymańska-Chargot, Monika; Miś, Antoni; Wilczewska, Agnieszka Z; Markiewicz, Karolina H

    2017-09-15

    FT-Raman spectroscopy, thermogravimetry and differential scanning calorimetry were used to study changes in structure of gluten proteins and their thermal properties influenced by four dietary fibre polysaccharides (microcrystalline cellulose, inulin, apple pectin and citrus pectin) during development of a model dough. The flour reconstituted from wheat starch and wheat gluten was mixed with the polysaccharides in five concentrations: 3%, 6%, 9%, 12% and 18%. The obtained results showed that all polysaccharides induced similar changes in secondary structure of gluten proteins concerning formation of aggregates (1604cm -1 ), H-bonded parallel- and antiparallel-β-sheets (1690cm -1 ) and H-bonded β-turns (1664cm -1 ). These changes concerned mainly glutenins since β-structures are characteristic for them. The observed structural changes confirmed hypothesis about partial dehydration of gluten network after polysaccharides addition. The gluten aggregation and dehydration processes were also reflected in the DSC results, while the TGA ones showed that gluten network remained thermally stable after polysaccharides addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Statistical Analysis of Coherent Ultrashort Light Pulse CDMA With Multiple Optical Amplifiers Using Additive Noise Model

    Science.gov (United States)

    Jamshidi, Kambiz; Salehi, Jawad A.

    2005-05-01

    This paper describes a study of the performance of various configurations for placing multiple optical amplifiers in a typical coherent ultrashort light pulse code-division multiple access (CULP-CDMA) communication system using the additive noise model. For this study, a comprehensive performance analysis was developed that takes into account multiple-access noise, noise due to optical amplifiers, and thermal noise using the saddle-point approximation technique. Prior to obtaining the overall system performance, the input/output statistical models for different elements of the system such as encoders/decoders,star coupler, and optical amplifiers were obtained. Performance comparisons between an ideal and lossless quantum-limited case and a typical CULP-CDMA with various losses exhibit more than 30 dB more power requirement to obtain the same bit-error rate (BER). Considering the saturation effect of optical amplifiers, this paper discusses an algorithm for amplifiers' gain setting in various stages of the network in order to overcome the nonlinear effects on signal modulation in optical amplifiers. Finally, using this algorithm,various configurations of multiple optical amplifiers in CULP-CDMA are discussed and the rules for the required optimum number of amplifiers are shown with their corresponding optimum locations to be implemented along the CULP-CDMA system.

  9. Generalized additive models reveal the intrinsic complexity of wood formation dynamics.

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K; Kiessé, Tristan Senga; Hartmann, Felix P; Barbeito, Ignacio; Fournier, Meriem

    2013-04-01

    The intra-annual dynamics of wood formation, which involves the passage of newly produced cells through three successive differentiation phases (division, enlargement, and wall thickening) to reach the final functional mature state, has traditionally been described in conifers as three delayed bell-shaped curves followed by an S-shaped curve. Here the classical view represented by the 'Gompertz function (GF) approach' was challenged using two novel approaches based on parametric generalized linear models (GLMs) and 'data-driven' generalized additive models (GAMs). These three approaches (GFs, GLMs, and GAMs) were used to describe seasonal changes in cell numbers in each of the xylem differentiation phases and to calculate the timing of cell development in three conifer species [Picea abies (L.), Pinus sylvestris L., and Abies alba Mill.]. GAMs outperformed GFs and GLMs in describing intra-annual wood formation dynamics, showing two left-skewed bell-shaped curves for division and enlargement, and a right-skewed bimodal curve for thickening. Cell residence times progressively decreased through the season for enlargement, whilst increasing late but rapidly for thickening. These patterns match changes in cell anatomical features within a tree ring, which allows the separation of earlywood and latewood into two distinct cell populations. A novel statistical approach is presented which renews our understanding of xylogenesis, a dynamic biological process in which the rate of cell production interplays with cell residence times in each developmental phase to create complex seasonal patterns.

  10. Additive surface complexation modeling of uranium(VI) adsorption onto quartz-sand dominated sediments.

    Science.gov (United States)

    Dong, Wenming; Wan, Jiamin

    2014-06-17

    Many aquifers contaminated by U(VI)-containing acidic plumes are composed predominantly of quartz-sand sediments. The F-Area of the Savannah River Site (SRS) in South Carolina (USA) is an example. To predict U(VI) mobility and natural attenuation, we conducted U(VI) adsorption experiments using the F-Area plume sediments and reference quartz, goethite, and kaolinite. The sediments are composed of ∼96% quartz-sand and 3-4% fine fractions of kaolinite and goethite. We developed a new humic acid adsorption method for determining the relative surface area abundances of goethite and kaolinite in the fine fractions. This method is expected to be applicable to many other binary mineral pairs, and allows successful application of the component additivity (CA) approach based surface complexation modeling (SCM) at the SRS F-Area and other similar aquifers. Our experimental results indicate that quartz has stronger U(VI) adsorption ability per unit surface area than goethite and kaolinite at pH ≤ 4.0. Our modeling results indicate that the binary (goethite/kaolinite) CA-SCM under-predicts U(VI) adsorption to the quartz-sand dominated sediments at pH ≤ 4.0. The new ternary (quartz/goethite/kaolinite) CA-SCM provides excellent predictions. The contributions of quartz-sand, kaolinite, and goethite to U(VI) adsorption and the potential influences of dissolved Al, Si, and Fe are also discussed.

  11. Adjustments in the Almod 3W2 code models for reproducing the net load trip test in Angra I nuclear power plant

    International Nuclear Information System (INIS)

    Camargo, C.T.M.; Madeira, A.A.; Pontedeiro, A.C.; Dominguez, L.

    1986-09-01

    The recorded traces got from the net load trip test in Angra I NPP yelded the oportunity to make fine adjustments in the ALMOD 3W2 code models. The changes are described and the results are compared against plant real data. (Author) [pt

  12. Maternal socialization goals, parenting styles, and social-emotional adjustment among Chinese and European American young adults: testing a mediation model.

    Science.gov (United States)

    Li, Yan; Costanzo, Philip R; Putallaz, Martha

    2010-01-01

    The authors compared the associations among perceived maternal socialization goals (self-development, filial piety, and collectivism), perceived maternal parenting styles (authoritative, authoritarian, and training), and the social-emotional adjustment (self-esteem, academic self-efficacy, and depression) between Chinese and European American young adults. The mediation processes in which socialization goals relate to young adults' adjustment outcomes through parenting styles were examined. Results showed that European American participants perceived higher maternal self-development socialization goals, whereas Chinese participants perceived higher maternal collectivism socialization goals as well as more authoritarian parenting. Cross-cultural similarities were found in the associations between perceived maternal authoritative parenting and socioemotional adjustment (e.g., higher self-esteem and higher academic self-efficacy) across the two cultural groups. However, perceived maternal authoritarian and training parenting styles were found only to be related to Chinese participants' adjustment (e.g., higher academic self-efficacy and lower depression). The mediation analyses showed that authoritative parenting significantly mediated the positive associations between the self-development and collectivism goal and socioemotional adjustment for both cultural groups. Additionally, training parenting significantly mediated the positive association between the filial piety goal and young adults' academic self-efficacy for the Chinese group only. Findings of this study highlight the importance of examining parental socialization goals in cross-cultural parenting research.

  13. Improving efficiency assessments using additive data envelopment analysis models: an application to contrasting dairy farming systems

    Directory of Open Access Journals (Sweden)

    Andreas Diomedes Soteriades

    2015-10-01

    Full Text Available Applying holistic indicators to assess dairy farm efficiency is essential for sustainable milk production. Data Envelopment Analysis (DEA has been instrumental for the calculation of such indicators. However, ‘additive’ DEA models have been rarely used in dairy research. This study presented an additive model known as slacks-based measure (SBM of efficiency and its advantages over DEA models used in most past dairy studies. First, SBM incorporates undesirable outputs as actual outputs of the production process. Second, it identifies the main production factors causing inefficiency. Third, these factors can be ‘priced’ to estimate the cost of inefficiency. The value of SBM for efficiency analyses was demonstrated with a comparison of four contrasting dairy management systems in terms of technical and environmental efficiency. These systems were part of a multiple-year breeding and feeding systems experiment (two genetic lines: select vs. control; and two feeding strategies: high forage vs. low forage, where the latter involved a higher proportion of concentrated feeds where detailed data were collected to strict protocols. The select genetic herd was more technically and environmentally efficient than the control herd, regardless of feeding strategy. However, the efficiency performance of the select herd was more volatile from year to year than that of the control herd. Overall, technical and environmental efficiency were strongly and positively correlated, suggesting that when technically efficient, the four systems were also efficient in terms of undesirable output reduction. Detailed data such as those used in this study are increasingly becoming available for commercial herds through precision farming. Therefore, the methods presented in this study are growing in importance.

  14. IA method for measuring the amount of hoar frost formation in the recuperation channels of ventilation systems using the adjustable mathematical model of this process

    Directory of Open Access Journals (Sweden)

    Shilin Aleksandr

    2017-01-01

    Full Text Available The paper presents a method for measuring the amount of hoar frost formation in the recuperation channels of ventilation systems using the adjustable mathematical model of the hoar frost process. The principle is based on the fact that the contour of the adjustment of the hoar frost model is included in the measurement in accordance with the measured pressure drop, which is proportional to the amount of hoar frost. Unlike the known measurement methods, it is proposed to use the state variables of the mathematical model as the measured value. These state variables are not subject to non-deterministic interferences and random influences. The paper presents simulation results confirming the adequacy of the dynamic model. In conclusion, an example of the use of a recuperation channel in the defrost management system is given.

  15. Generalized Concentration Addition Modeling Predicts Mixture Effects of Environmental PPARγ Agonists.

    Science.gov (United States)

    Watt, James; Webster, Thomas F; Schlezinger, Jennifer J

    2016-09-01

    The vast array of potential environmental toxicant combinations necessitates the development of efficient strategies for predicting toxic effects of mixtures. Current practices emphasize the use of concentration addition to predict joint effects of endocrine disrupting chemicals in coexposures. Generalized concentration addition (GCA) is one such method for predicting joint effects of coexposures to chemicals and has the advantage of allowing for mixture components to have differences in efficacy (ie, dose-response curve maxima). Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear receptor that plays a central role in regulating lipid homeostasis, insulin sensitivity, and bone quality and is the target of an increasing number of environmental toxicants. Here, we tested the applicability of GCA in predicting mixture effects of therapeutic (rosiglitazone and nonthiazolidinedione partial agonist) and environmental PPARγ ligands (phthalate compounds identified using EPA's ToxCast database). Transcriptional activation of human PPARγ1 by individual compounds and mixtures was assessed using a peroxisome proliferator response element-driven luciferase reporter. Using individual dose-response parameters and GCA, we generated predictions of PPARγ activation by the mixtures, and we compared these predictions with the empirical data. At high concentrations, GCA provided a better estimation of the experimental response compared with 3 alternative models: toxic equivalency factor, effect summation and independent action. These alternatives provided reasonable fits to the data at low concentrations in this system. These experiments support the implementation of GCA in mixtures analysis with endocrine disrupting compounds and establish PPARγ as an important target for further studies of chemical mixtures. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e

  16. A ¤nonparametric dynamic additive regression model for longitudinal data

    DEFF Research Database (Denmark)

    Martinussen, T.; Scheike, T. H.

    2000-01-01

    dynamic linear models, estimating equations, least squares, longitudinal data, nonparametric methods, partly conditional mean models, time-varying-coefficient models......dynamic linear models, estimating equations, least squares, longitudinal data, nonparametric methods, partly conditional mean models, time-varying-coefficient models...

  17. Motor models and transient analysis for high-temperature, superconductor switch-based adjustable speed drive applications. Final report

    International Nuclear Information System (INIS)

    Bailey, J.M.

    1996-06-01

    New high-temperature superconductor (HTSC) technology may allow development of an energy-efficient power electronics switch for adjustable speed drive (ASD) applications involving variable-speed motors, superconducting magnetic energy storage systems, and other power conversion equipment. This project developed a motor simulation module for determining optimal applications of HTSC-based power switches in ASD systems

  18. Performance evaluation of paper embossing tools produced by fused deposition modelling additive manufacturing technology

    Directory of Open Access Journals (Sweden)

    Gordana Delić

    2017-12-01

    Full Text Available From its beginnings, up to a few years ago, additive manufacturing technology was able to produce models or prototypes which have limited use, because of materials mechanical properties. With advancement and invention of new materials, this is changing. Now, it is possible to create 3D prints that can be used as final products or functional tools, using technology and materials with low environmental impact. The goal of this study was to examine opportunities for production of paper embossing tools by fused deposition modelling (FDM 3D printing. This study emphasises the use of environmentally friendly poly-lactic acid (PLA materials in FDM technology, contrary to the conventional method using metal alloys and acids. Embossing of line elements and letters using 3D printed embossing tools was done on six different types of paper. Embossing force was applied using SHIMADZU EZ-LX Compact Tabletop Testing Machine. Each type of paper was repeatedly embossed using different values of embossing force (in 250 N increments, starting at 1000 N to determine the optimal embossing force for each specific paper type. When determined, the optimal embossing force was used on ten samples for each paper type. Results of embossing were analysed and evaluated. The analysis consisted of investigating the effects of the applied embossing force and characteristics such as paper basis weight, paper structure, surface characteristic and fibre direction of the paper. Results show that paper characteristics determine the embossing force required for achieving a good embossing result. This means that with the right amount of embossing force, letters and borderlines can be equally well formed by the embossing process regardless of paper weight, surface characteristics, etc. Embossing tools produced in this manner can be used in case of the embossing elements that are not complex. The reason for this is the limitation of FDM technology and lack of precision needed for fine

  19. A Monte Carlo-adjusted goodness-of-fit test for parametric models describing spatial point patterns

    KAUST Repository

    Dao, Ngocanh

    2014-04-03

    Assessing the goodness-of-fit (GOF) for intricate parametric spatial point process models is important for many application fields. When the probability density of the statistic of the GOF test is intractable, a commonly used procedure is the Monte Carlo GOF test. Additionally, if the data comprise a single dataset, a popular version of the test plugs a parameter estimate in the hypothesized parametric model to generate data for theMonte Carlo GOF test. In this case, the test is invalid because the resulting empirical level does not reach the nominal level. In this article, we propose a method consisting of nested Monte Carlo simulations which has the following advantages: the bias of the resulting empirical level of the test is eliminated, hence the empirical levels can always reach the nominal level, and information about inhomogeneity of the data can be provided.We theoretically justify our testing procedure using Taylor expansions and demonstrate that it is correctly sized through various simulation studies. In our first data application, we discover, in agreement with Illian et al., that Phlebocarya filifolia plants near Perth, Australia, can follow a homogeneous Poisson clustered process that provides insight into the propagation mechanism of these plants. In our second data application, we find, in contrast to Diggle, that a pairwise interaction model provides a good fit to the micro-anatomy data of amacrine cells designed for analyzing the developmental growth of immature retina cells in rabbits. This article has supplementary material online. © 2013 American Statistical Association, Institute of Mathematical Statistics, and Interface Foundation of North America.

  20. Gadolinium deposition in the brain: association with various GBCAs using a generalized additive model

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sohi; Lee, Ho-Joon; Han, Kyunghwa; Park, Yae-Won; Choi, Yoon Seong; Ahn, Sung Soo; Kim, Jinna; Lee, Seung-Koo [Yonsei University College of Medicine, Department of Radiology, Severance Hospital, Research Institute of Radiological Science, Seoul (Korea, Republic of)

    2017-08-15

    To determine the relationship between the number of administrations of various gadolinium-based contrast agents (GBCAs) and increased T1 signal intensity in the globus pallidus (GP) and dentate nucleus (DN). This retrospective study included 122 patients who underwent double-dose GBCA-enhanced magnetic resonance imaging. Two radiologists calculated GP-to-thalamus (TH) signal intensity ratio, DN-to-pons signal intensity ratio and relative change (R{sub change}) between the baseline and final examinations. Interobserver agreement was evaluated. The relationships between R{sub change} and several factors, including number of each GBCA administrations, were analysed using a generalized additive model. Six patients (4.9%) received linear GBCAs (mean 20.8 number of administration; range 15-30), 44 patients (36.1%) received macrocyclic GBCAs (mean 26.1; range 14-51) and 72 patients (59.0%) received both types of GBCAs (mean 31.5; range 12-65). Interobserver agreement was almost perfect (0.99; 95% CI: 0.99-0.99). R{sub change} (DN:pons) was associated with gadodiamide (p = 0.006) and gadopentetate dimeglumine (p < 0.001), but not with other GBCAs. R{sub change} (GP:TH) was not associated with GBCA administration. Previous administration of linear agents gadoiamide and gadopentetate dimeglumine is associated with increased T1 signal intensity in the DN, whereas macrocyclic GBCAs do not show an association. (orig.)

  1. Design and modeling of an additive manufactured thin shell for x-ray astronomy

    Science.gov (United States)

    Feldman, Charlotte; Atkins, Carolyn; Brooks, David; Watson, Stephen; Cochrane, William; Roulet, Melanie; Willingale, Richard; Doel, Peter

    2017-09-01

    Future X-ray astronomy missions require light-weight thin shells to provide large collecting areas within the weight limits of launch vehicles, whilst still delivering angular resolutions close to that of Chandra (0.5 arc seconds). Additive manufacturing (AM), also known as 3D printing, is a well-established technology with the ability to construct or `print' intricate support structures, which can be both integral and light-weight, and is therefore a candidate technique for producing shells for space-based X-ray telescopes. The work described here is a feasibility study into this technology for precision X-ray optics for astronomy and has been sponsored by the UK Space Agency's National Space Technology Programme. The goal of the project is to use a series of test samples to trial different materials and processes with the aim of developing a viable path for the production of an X-ray reflecting prototype for astronomical applications. The initial design of an AM prototype X-ray shell is presented with ray-trace modelling and analysis of the X-ray performance. The polishing process may cause print-through from the light-weight support structure on to the reflecting surface. Investigations in to the effect of the print-through on the X-ray performance of the shell are also presented.

  2. Exposure as Duration and Distance in Telematics Motor Insurance Using Generalized Additive Models

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Boucher

    2017-09-01

    Full Text Available In Pay-As-You-Drive (PAYD automobile insurance, the premium is fixed based on the distance traveled, while in usage-based insurance (UBI the driving patterns of the policyholder are also considered. In those schemes, drivers who drive more pay a higher premium compared to those with the same characteristics who drive only occasionally, because the former are more exposed to the risk of accident. In this paper, we analyze the simultaneous effect of the distance traveled and exposure time on the risk of accident by using Generalized Additive Models (GAM. We carry out an empirical application and show that the expected number of claims (1 stabilizes once a certain number of accumulated distance-driven is reached and (2 it is not proportional to the duration of the contract, which is in contradiction to insurance practice. Finally, we propose to use a rating system that takes into account simultaneously exposure time and distance traveled in the premium calculation. We think that this is the trend the automobile insurance market is going to follow with the eruption of telematics data.

  3. Predictive modeling of solidification during laser additive manufacturing of nickel superalloys: recent developments, future directions

    Science.gov (United States)

    Ghosh, Supriyo

    2018-01-01

    Additive manufacturing (AM) processes produce parts with improved physical, chemical, and mechanical properties compared to conventional manufacturing processes. In AM processes, intricate part geometries are produced from multicomponent alloy powder, in a layer-by-layer fashion with multipass laser melting, solidification, and solid-state phase transformations, in a shorter manufacturing time, with minimal surface finishing, and at a reasonable cost. However, there is an increasing need for post-processing of the manufactured parts via, for example, stress relieving heat treatment and hot isostatic pressing to achieve homogeneous microstructure and properties at all times. Solidification in an AM process controls the size, shape, and distribution of the grains, the growth morphology, the elemental segregation and precipitation, the subsequent solid-state phase changes, and ultimately the material properties. The critical issues in this process are linked with multiphysics (such as fluid flow and diffusion of heat and mass) and multiscale (lengths, times and temperature ranges) challenges that arise due to localized rapid heating and cooling during AM processing. The alloy chemistry-process-microstructure-property-performance correlation in this process will be increasingly better understood through multiscale modeling and simulation.

  4. Statistical inference for the additive hazards model under outcome-dependent sampling.

    Science.gov (United States)

    Yu, Jichang; Liu, Yanyan; Sandler, Dale P; Zhou, Haibo

    2015-09-01

    Cost-effective study design and proper inference procedures for data from such designs are always of particular interests to study investigators. In this article, we propose a biased sampling scheme, an outcome-dependent sampling (ODS) design for survival data with right censoring under the additive hazards model. We develop a weighted pseudo-score estimator for the regression parameters for the proposed design and derive the asymptotic properties of the proposed estimator. We also provide some suggestions for using the proposed method by evaluating the relative efficiency of the proposed method against simple random sampling design and derive the optimal allocation of the subsamples for the proposed design. Simulation studies show that the proposed ODS design is more powerful than other existing designs and the proposed estimator is more efficient than other estimators. We apply our method to analyze a cancer study conducted at NIEHS, the Cancer Incidence and Mortality of Uranium Miners Study, to study the risk of radon exposure to cancer.

  5. Analysis of case-parent trios for imprinting effect using a loglinear model with adjustment for sex-of-parent-specific transmission ratio distortion

    DEFF Research Database (Denmark)

    Huang, Lam Opal; Infante-Rivard, Claire; Labbe, Aurélie

    2017-01-01

    of the minor allele in control-trios can be added to the loglinear model to adjust for TRD. Adjusting the model removes the inflation in the genotype relative risk (RR) estimate and Type 1 error introduced by non-sex-of-parent-specific TRD. We now propose to further extend this model to estimate an imprinting......Transmission ratio distortion (TRD) is a phenomenon where parental transmission of disease allele to the child does not follow the Mendelian inheritance ratio. TRD occurs in a sex-of-parent-specific or non-sex-of-parent-specific manner. An offset computed from the transmission probability...... parameter. Some evidence suggests that more than 1% of all mammalian genes are imprinted. In the presence of imprinting, for example, the offspring inheriting an over-transmitted disease allele from the parent with a higher expression level in a neighboring gene is over-represented in the sample. TRD...

  6. Mathematical modeling and experimental validation of Phaeodactylum tricornutum microalgae growth rate with glycerol addition

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Keli Cristiane Correia; Ribeiro, Robert Luis Lara; Santos, Kassiana Ribeiro dos; Mariano, Andre Bellin [Mariano Center for Research and Development of Sustainable Energy (NPDEAS), Curitiba, PR (Brazil); Vargas, Jose Viriato Coelho [Departament of Mechanical Engineering, Federal University of Parana (UFPR) Curitiba, PR (Brazil)

    2010-07-01

    The Brazilian National Program for Bio fuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO{sub 2}. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10{sup th} and 14{sup th} days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. It was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l{sup -1}. In order to compare

  7. Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario

    Science.gov (United States)

    Kashimura, Hiroki; Abe, Manabu; Watanabe, Shingo; Sekiya, Takashi; Ji, Duoying; Moore, John C.; Cole, Jason N. S.; Kravitz, Ben

    2017-03-01

    This study evaluates the forcing, rapid adjustment, and feedback of net shortwave radiation at the surface in the G4 experiment of the Geoengineering Model Intercomparison Project by analysing outputs from six participating models. G4 involves injection of 5 Tg yr-1 of SO2, a sulfate aerosol precursor, into the lower stratosphere from year 2020 to 2069 against a background scenario of RCP4.5. A single-layer atmospheric model for shortwave radiative transfer is used to estimate the direct forcing of solar radiation management (SRM), and rapid adjustment and feedbacks from changes in the water vapour amount, cloud amount, and surface albedo (compared with RCP4.5). The analysis shows that the globally and temporally averaged SRM forcing ranges from -3.6 to -1.6 W m-2, depending on the model. The sum of the rapid adjustments and feedback effects due to changes in the water vapour and cloud amounts increase the downwelling shortwave radiation at the surface by approximately 0.4 to 1.5 W m-2 and hence weaken the effect of SRM by around 50 %. The surface albedo changes decrease the net shortwave radiation at the surface; it is locally strong (˜ -4 W m-2) in snow and sea ice melting regions, but minor for the global average. The analyses show that the results of the G4 experiment, which simulates sulfate geoengineering, include large inter-model variability both in the direct SRM forcing and the shortwave rapid adjustment from change in the cloud amount, and imply a high uncertainty in modelled processes of sulfate aerosols and clouds.

  8. The development, evaluation, and application of O3 flux and flux-response models for additional agricultural crops

    Science.gov (United States)

    L. D. Emberson; W. J. Massman; P. Buker; G. Soja; I. Van De Sand; G. Mills; C. Jacobs

    2006-01-01

    Currently, stomatal O3 flux and flux-response models only exist for wheat and potato (LRTAP Convention, 2004), as such there is a need to extend these models to include additional crop types. The possibility of establishing robust stomatal flux models for five agricultural crops (tomato, grapevine, sugar beet, maize and sunflower) was investigated. These crops were...

  9. Correction: Utility of a single adjusting compartment: a novel methodology for whole body physiologically-based pharmacokinetic modelling

    Directory of Open Access Journals (Sweden)

    Hori Wataru

    2009-12-01

    Full Text Available Abstract After our work was published, we found that some of the terms in the equations were incorrect and that there were some typographical errors in the abbreviations. In the section 'Single adjusting compartment' in Materials and Methods, VS should be VSAC. In the last paragraph of Results, QSAC should be QSAC. The correct equations are included in this article. These corrections will not affect the results of this study.

  10. The model of children's social adjustment under the gender-roles absence in single-parent families.

    Science.gov (United States)

    Chen, I-Jun; Zhang, Hailun; Wei, Bingsi; Guo, Zeyao

    2018-01-14

    This study aimed to evaluate the effects of the gender-role types and child-rearing gender-role attitude of the single-parents, as well as their children's gender role traits and family socio-economic status, on social adjustment. We recruited 458 pairs of single parents and their children aged 8-18 by purposive sampling. The research tools included the Family Socio-economic Status Questionnaire, Sex Role Scales, Parental Child-rearing Gender-role Attitude Scale and Social Adjustment Scale. The results indicated: (a) single mothers' and their daughters' feminine traits were both higher than their masculine traits, and sons' masculine traits were higher than their feminine traits; the majority gender-role type of single parents and their children was androgyny; significant differences were found between children's gender-role types depending on different raiser, the proportion of girls' masculine traits raised by single fathers was significantly higher than those who were raised by single mothers; (b) family socio-economic status and single parents' gender-role types positively influenced parental child-rearing gender-role attitude, which in turn, influenced the children's gender traits, and further affected children's social adjustment. © 2018 International Union of Psychological Science.

  11. On-board adaptive model for state of charge estimation of lithium-ion batteries based on Kalman filter with proportional integral-based error adjustment

    Science.gov (United States)

    Wei, Jingwen; Dong, Guangzhong; Chen, Zonghai

    2017-10-01

    With the rapid development of battery-powered electric vehicles, the lithium-ion battery plays a critical role in the reliability of vehicle system. In order to provide timely management and protection for battery systems, it is necessary to develop a reliable battery model and accurate battery parameters estimation to describe battery dynamic behaviors. Therefore, this paper focuses on an on-board adaptive model for state-of-charge (SOC) estimation of lithium-ion batteries. Firstly, a first-order equivalent circuit battery model is employed to describe battery dynamic characteristics. Then, the recursive least square algorithm and the off-line identification method are used to provide good initial values of model parameters to ensure filter stability and reduce the convergence time. Thirdly, an extended-Kalman-filter (EKF) is applied to on-line estimate battery SOC and model parameters. Considering that the EKF is essentially a first-order Taylor approximation of battery model, which contains inevitable model errors, thus, a proportional integral-based error adjustment technique is employed to improve the performance of EKF method and correct model parameters. Finally, the experimental results on lithium-ion batteries indicate that the proposed EKF with proportional integral-based error adjustment method can provide robust and accurate battery model and on-line parameter estimation.

  12. Evaluation of additional biogeochemical impacts on mitigation pathways in an energy sytem integrated assessment model.

    Science.gov (United States)

    Dessens, O.

    2017-12-01

    level of decarbonisation. In extreme condition (positive correlation between the 3 issues discussed) the integrated assessment model TIAM-UCL creates pathways requiring additional negative emission technologies at the end of this century to keep temperature change well below 2°C.

  13. The relation between air pollution and respiratory deaths in Tehran, Iran- using generalized additive models.

    Science.gov (United States)

    Dehghan, Azizallah; Khanjani, Narges; Bahrampour, Abbas; Goudarzi, Gholamreza; Yunesian, Masoud

    2018-03-20

    Some epidemiological evidence has shown a relation between ambient air pollution and adverse health outcomes. The aim of this study was to investigate the effect of air pollution on mortality from respiratory diseases in Tehran, Iran. In this ecological study, air pollution data was inquired from the Tehran Province Environmental Protection Agency and the Tehran Air Quality Control Company. Meteorological data was collected from the Tehran Meteorology Organization and mortality data from the Tehran Cemetery Mortality Registration. Generalized Additive Models (GAM) was used for data analysis with different lags, up to 15 days. A 10-unit increase in all pollutants except CO (1-unit) was used to compute the Relative Risk of deaths. During 2005 until 2014, 37,967 respiratory deaths occurred in Tehran in which 21,913 (57.7%) were male. The strongest relationship between NO 2 and PM 10 and respiratory death was seen on the same day (lag 0), and was respectively (RR = 1.04, 95% CI: 1.02-1.07) and (RR = 1.03, 95% CI: 1.02-1.04). O 3 and PM 2.5 had the strongest relationship with respiratory deaths on lag 2 and 1 respectively, and the RR was equal to 1.03, 95% CI: 1.01-1.05 and 1.06, 95% CI: 1.02-1.10 respectively. NO 2 , O 3 , PM 10 and PM 2.5 also showed significant relations with respiratory deaths in the older age groups. The findings of this study showed that O 3 , NO 2 , PM 10 and PM 2.5 air pollutants were related to respiratory deaths in Tehran. Reducing ambient air pollution can save lives in Tehran.

  14. LSL: a logarithmic least-squares adjustment method

    International Nuclear Information System (INIS)

    Stallmann, F.W.

    1982-01-01

    To meet regulatory requirements, spectral unfolding codes must not only provide reliable estimates for spectral parameters, but must also be able to determine the uncertainties associated with these parameters. The newer codes, which are more appropriately called adjustment codes, use the least squares principle to determine estimates and uncertainties. The principle is simple and straightforward, but there are several different mathematical models to describe the unfolding problem. In addition to a sound mathematical model, ease of use and range of options are important considerations in the construction of adjustment codes. Based on these considerations, a least squares adjustment code for neutron spectrum unfolding has been constructed some time ago and tentatively named LSL

  15. The multi-factorial origins of Chronic Traumatic Encephalopathy (CTE) symptomology in post-career athletes: The athlete post-career adjustment (AP-CA) model.

    Science.gov (United States)

    Gaetz, Michael

    2017-05-01

    CTE has two prominent components: the pathophysiology that is detected in the brain postmortem and the symptomology that is present in the interval between retirement and end of life. CTE symptomology has been noted to include memory difficulties, aggression, depression, explosivity, and executive dysfunction at early stages progressing to problems with attention, mood swings, visuospatial difficulties, confusion, progressive dementia, and suicidality (e.g. McKee et al. (2012), Omalu et al. (2010a-c), McKee et al. (2009)). There are a number of assumptions embedded within the current CTE literature: The first is the assumption that CTE symptomology reported by athletes and their families is the product of the pathophysiology change detected post-mortem (e.g. McKee et al. (2009)). At present, there is little scientific evidence to suggest that all CTE symptomology is the product of CTE pathophysiology. It has been assumed that CTE pathophysiology causes CTE symptomology (Meehan et al. (2015), Iverson et al. (2016)) but this link has never been scientifically validated. The purpose of the present work is to provide a multi-factorial theoretical framework to account for the symptomology reported by some athletes who sustain neurotrauma during their careers that will lead to a more systematic approach to understanding post-career symptomology. There is significant overlap between the case reports of athletes with post-mortem diagnoses of CTE, and symptom profiles of those with a history of substance use, chronic pain, and athlete career transition stress. The athlete post-career adjustment (AP-CA) model is intended to explain some of the symptoms that athletes experience at the end of their careers or during retirement. The AP-CA model consists of four elements: neurotrauma, chronic pain, substance use, and career transition stress. Based on the existing literature, it is clear that any one of the four elements of the AP-CA model can account for a significant number of

  16. Development of a three dimensional homogeneous calculation model for the BFS-62 critical experiment. Preparation of adjusted equivalent measured values for sodium void reactivity values. Final report

    International Nuclear Information System (INIS)

    Manturov, G.; Semenov, M.; Seregin, A.; Lykova, L.

    2004-01-01

    The BFS-62 critical experiments are currently used as 'benchmark' for verification of IPPE codes and nuclear data, which have been used in the study of loading a significant amount of Pu in fast reactors. The BFS-62 experiments have been performed at BFS-2 critical facility of IPPE (Obninsk). The experimental program has been arranged in such a way that the effect of replacement of uranium dioxied blanket by the steel reflector as well as the effect of replacing UOX by MOX on the main characteristics of the reactor model was studied. Wide experimental program, including measurements of the criticality-keff, spectral indices, radial and axial fission rate distributions, control rod mock-up worth, sodium void reactivity effect SVRE and some other important nuclear physics parameters, was fulfilled in the core. Series of 4 BFS-62 critical assemblies have been designed for studying the changes in BN-600 reactor physics from existing state to hybrid core. All the assemblies are modeling the reactor state prior to refueling, i.e. with all control rod mock-ups withdrawn from the core. The following items are chosen for the analysis in this report: Description of the critical assembly BFS-62-3A as the 3rd assembly in a series of 4 BFS critical assemblies studying BN-600 reactor with MOX-UOX hybrid zone and steel reflector; Development of a 3D homogeneous calculation model for the BFS-62-3A critical experiment as the mock-up of BN-600 reactor with hybrid zone and steel reflector; Evaluation of measured nuclear physics parameters keff and SVRE (sodium void reactivity effect); Preparation of adjusted equivalent measured values for keff and SVRE. Main series of calculations are performed using 3D HEX-Z diffusion code TRIGEX in 26 groups, with the ABBN-93 cross-section set. In addition, precise calculations are made, in 299 groups and Ps-approximation in scattering, by Monte-Carlo code MMKKENO and discrete ordinate code TWODANT. All calculations are based on the common system

  17. Efficient Semiparametric Marginal Estimation for the Partially Linear Additive Model for Longitudinal/Clustered Data

    KAUST Repository

    Carroll, Raymond

    2009-04-23

    We consider the efficient estimation of a regression parameter in a partially linear additive nonparametric regression model from repeated measures data when the covariates are multivariate. To date, while there is some literature in the scalar covariate case, the problem has not been addressed in the multivariate additive model case. Ours represents a first contribution in this direction. As part of this work, we first describe the behavior of nonparametric estimators for additive models with repeated measures when the underlying model is not additive. These results are critical when one considers variants of the basic additive model. We apply them to the partially linear additive repeated-measures model, deriving an explicit consistent estimator of the parametric component; if the errors are in addition Gaussian, the estimator is semiparametric efficient. We also apply our basic methods to a unique testing problem that arises in genetic epidemiology; in combination with a projection argument we develop an efficient and easily computed testing scheme. Simulations and an empirical example from nutritional epidemiology illustrate our methods.

  18. Border tax adjustments for additional costs engendered by internal and EU environmental protection measures. Implementation options and WTO admissibility; Grenzsteuerausgleich fuer Mehrkosten infolge nationaler/europaeischer Umweltschutzinstrumente. Gestaltungsmoeglichkeiten und WTO-rechtliche Zulaessigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Hilbert, Jacqueline; Berg, Holger (comps.)

    2008-04-15

    At the end of the year 2006, France proposed the introduction of a 'climatic tariff' into the discussion of the international climatic protection. The 'climatic tariff' shall adjust extra costs, which result from the domestic production by means of environmental protection instruments and to which the import goods are not exposed, with import/export compensatory payments in the form of import duties and/or taxes on import goods. The introduction of an import/export compensatory payment system aims to load imported goods equivalent to domestic products in order to adjust competitive disadvantages. In the contribution under consideration the authors report on possibilities and problems of design for an import/export tax compensatory. The authors examine the validity of the measures of import/export compensation from legal view the World Trade Organization (Geneva, Switzerland) based on the General Agreement on Tariffs and Trade.

  19. Modeling and identification for the adjustable control of generation processes; Modelado e identificacion para el control autoajustable de procesos de generacion

    Energy Technology Data Exchange (ETDEWEB)

    Ricano Castillo, Juan Manuel; Palomares Gonzalez, Daniel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    The recursive technique of the method of minimum squares is employed to obtain a multivariable model of the self regressive mobile mean type, needed for the design of a multivariable, self-adjustable controller self adjustable multivariable. In this article the employed technique and the results obtained are described with the characterization of the model structure and the parametric estimation. The convergency velocity curves are observed towards the parameters` numerical values. [Espanol] La tecnica recursiva del metodo de los minimos cuadrados se emplea para obtener un modelo multivariable de tipo autorregresivo de promedio movil, necesario para el diseno de un controlador autoajustable muitivariable. En el articulo, se describe la tecnica empleada y los resultados obtenidos con la caracterizacion de la estructura del modelo y la estimacion parametrica. Se observan las curvas de la velocidad de convergencia hacia los valores numericos de los parametros.

  20. Suitability of a three-dimensional model to measure empathy and its relationship with social and normative adjustment in Spanish adolescents: a cross-sectional study.

    Science.gov (United States)

    Herrera-López, Mauricio; Gómez-Ortiz, Olga; Ortega-Ruiz, Rosario; Jolliffe, Darrick; Romera, Eva M

    2017-09-25

    (1) To examine the psychometric properties of the Basic Empathy Scale (BES) with Spanish adolescents, comparing a two and a three-dimensional structure;(2) To analyse the relationship between the three-dimensional empathy and social and normative adjustment in school. Transversal and ex post facto retrospective study. Confirmatory factorial analysis, multifactorial invariance analysis and structural equations models were used. 747 students (51.3% girls) from Cordoba, Spain, aged 12-17 years (M=13.8; SD=1.21). The original two-dimensional structure was confirmed (cognitive empathy, affective empathy), but a three-dimensional structure showed better psychometric properties, highlighting the good fit found in confirmatory factorial analysis and adequate internal consistent valued, measured with Cronbach's alpha and McDonald's omega. Composite reliability and average variance extracted showed better indices for a three-factor model. The research also showed evidence of measurement invariance across gender. All the factors of the final three-dimensional BES model were direct and significantly associated with social and normative adjustment, being most strongly related to cognitive empathy. This research supports the advances in neuroscience, developmental psychology and psychopathology through a three-dimensional version of the BES, which represents an improvement in the original two-factorial model. The organisation of empathy in three factors benefits the understanding of social and normative adjustment in adolescents, in which emotional disengagement favours adjusted peer relationships. Psychoeducational interventions aimed at improving the quality of social life in schools should target these components of empathy. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  1. An Evaluation of the Adjusted DeLone and McLean Model of Information Systems Success; the case of financial information system in Ferdowsi University of Mashhad

    OpenAIRE

    Mohammad Lagzian; Shamsoddin Nazemi; Fatemeh Dadmand

    2012-01-01

    Assessing the success of information systems within organizations has been identified as one of the most critical subjects of information system management in both public and private organizations. It is therefore important to measure the success of information systems from the user's perspective. The purpose of the current study was to evaluate the degree of information system success by the adjusted DeLone and McLean’s model in the field financial information system (FIS) in an Iranian Univ...

  2. MODELING OF THE HEAT PUMP STATION ADJUSTABLE LOOP OF AN INTERMEDIATE HEAT-TRANSFER AGENT (Part I

    Directory of Open Access Journals (Sweden)

    Sit B.

    2009-08-01

    Full Text Available There are examined equations of dynamics and statics of an adjustable intermediate loop of heat pump carbon dioxide station in this paper. Heat pump station is a part of the combined heat supply system. Control of transferred thermal capacity from the source of low potential heat source is realized by means of changing the speed of circulation of a liquid in the loop and changing the area of a heat-transmitting surface, both in the evaporator, and in the intermediate heat exchanger depending on the operating parameter, for example, external air temperature and wind speed.

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

    Science.gov (United States)

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

    2011-01-01

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

  4. Evaluation of paediatric cardiosurgical model in Croatia by using the Aristotle basic complexity score and the risk adjustment for congenital cardiac surgery-1 method.

    Science.gov (United States)

    Dilber, Daniel; Malcic, Ivan

    2010-08-01

    The Aristotle basic complexity score and the risk adjustment in congenital cardiac surgery-1 method were developed and used to compare outcomes of congenital cardiac surgery. Both methods were used to compare results of procedures performed on our patients in Croatian cardiosurgical centres and results of procedures were taken abroad. The study population consisted of all patients with congenital cardiac disease born to Croatian residents between 1 October, 2002 and 1 October, 2007 undergoing a cardiovascular operation during this period. Of the 556 operations, the Aristotle basic complexity score could be assigned to 553 operations and the risk adjustment in congenital cardiac surgery-1 method to 536 operations. Procedures were performed in two institutions in Croatia and seven institutions abroad. The average complexity for cardiac procedures performed in Croatia was significantly lower. With both systems, along with the increase in complexity, there is also an increase in mortality before discharge and postoperative length of stay. Only after the adjustment for complexity there are marked differences in mortality and occurrence of postoperative complications. Both, the Aristotle basic complexity score and the risk adjustment in congenital cardiac surgery-1 method were predictive of in-hospital mortality as well as prolonged postoperative length to stay, and can be used as a tool in our country to evaluate a cardiosurgical model and recognise potential problems.

  5. Application of power addition as modelling technique for flow processes: Two case studies

    CSIR Research Space (South Africa)

    de Wet, P

    2010-05-01

    Full Text Available through diaphragm valve and the fluidisation of a packed bed, are analysed as case studies. Empirical results are investigated for possible asymptotic bounds where after power addition is applied to the functional dependencies. The outcome is compared...

  6. Multi-Scale Modeling of Crack Nucleation and Growth in Additively Manufactured Alloys

    Data.gov (United States)

    National Aeronautics and Space Administration — Additive manufacturing (AM) promises growth in design space, increased speed of production, and decreased cost to aircraft and space technology engineering. For this...

  7. Manufacturing Decision Tree Model Optimization for Finishing Additive Manufactured Components, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I program addresses the challenge of gaining the necessary knowledge needed to support certification of additive manufacturing (AM) hardware and achieving...

  8. Modeling of Microstructure Formation in Additively Manufactured IN718 with Emphasis on Porosity Prediction

    Data.gov (United States)

    National Aeronautics and Space Administration — Additive manufacturing of metal parts is experiencing strong growth as powder bed machines in particular become more widely available. Although parts are being...

  9. Materials Testing and Cost Modeling for Composite Parts Through Additive Manufacturing

    Science.gov (United States)

    2016-04-30

    related to production quantities 9 Bulk-forming processes 0.11-5.82 kWh/kg for injection molding 0.62-7.78 kWh/kg for metal casting Subtractive...in manufacturing aircraft components. The additive process provides a possible means to reduce an aircraft’s lifecycle cost (LCC), but the effects...of changed process parameters of additive manufacturing machines on final material characteristics are not well known. This research explores these

  10. The rise and fall of divorce - a sociological adjustment of becker’s model of the marriage market

    DEFF Research Database (Denmark)

    Andersen, Signe Hald; Hansen, Lars Gårn

    Despite the strong and persistent influence of Gary Becker’s marriage model, the model does not completely explain the observed correlation between married women’s labor market participation and overall divorce rates. In this paper we show how a simple sociologically inspired extension of the model...... this aspect into Becker’s model, the model provides predictions of divorce rates and causes that fit more closely with empirical observations. (JEL: J1)...

  11. The importance of extent of choroid plexus cauterization in addition to endoscopic third ventriculostomy for infantile hydrocephalus: a retrospective North American observational study using propensity score-adjusted analysis.

    Science.gov (United States)

    Fallah, Aria; Weil, Alexander G; Juraschka, Kyle; Ibrahim, George M; Wang, Anthony C; Crevier, Louis; Tseng, Chi-Hong; Kulkarni, Abhaya V; Ragheb, John; Bhatia, Sanjiv

    2017-12-01

    OBJECTIVE Combined endoscopic third ventriculostomy (ETC) and choroid plexus cauterization (CPC)-ETV/CPC- is being investigated to increase the rate of shunt independence in infants with hydrocephalus. The degree of CPC necessary to achieve improved rates of shunt independence is currently unknown. METHODS Using data from a single-center, retrospective, observational cohort study involving patients who underwent ETV/CPC for treatment of infantile hydrocephalus, comparative statistical analyses were performed to detect a difference in need for subsequent CSF diversion procedure in patients undergoing partial CPC (describes unilateral CPC or bilateral CPC that only extended from the foramen of Monro [FM] to the atrium on one side) or subtotal CPC (describes CPC extending from the FM to the posterior temporal horn bilaterally) using a rigid neuroendoscope. Propensity scores for extent of CPC were calculated using age and etiology. Propensity scores were used to perform 1) case-matching comparisons and 2) Cox multivariable regression, adjusting for propensity score in the unmatched cohort. Cox multivariable regression adjusting for age and etiology, but not propensity score was also performed as a third statistical technique. RESULTS Eighty-four patients who underwent ETV/CPC had sufficient data to be included in the analysis. Subtotal CPC was performed in 58 patients (69%) and partial CPC in 26 (31%). The ETV/CPC success rates at 6 and 12 months, respectively, were 49% and 41% for patients undergoing subtotal CPC and 35% and 31% for those undergoing partial CPC. Cox multivariate regression in a 48-patient cohort case-matched by propensity score demonstrated no added effect of increased extent of CPC on ETV/CPC survival (HR 0.868, 95% CI 0.422-1.789, p = 0.702). Cox multivariate regression including all patients, with adjustment for propensity score, demonstrated no effect of extent of CPC on ETV/CPC survival (HR 0.845, 95% CI 0.462-1.548, p = 0.586). Cox multivariate

  12. Positioning and number of nutritional levels in dose-response trials to estimate the optimal-level and the adjustment of the models

    Directory of Open Access Journals (Sweden)

    Fernando Augusto de Souza

    2014-07-01

    Full Text Available The aim of this research was to evaluate the influence of the number and position of nutrient levels used in dose-response trials in the estimation of the optimal-level (OL and the goodness of fit on the models: quadratic polynomial (QP, exponential (EXP, linear response plateau (LRP and quadratic response plateau (QRP. It was used data from dose-response trials realized in FCAV-Unesp Jaboticabal considering the homogeneity of variances and normal distribution. The fit of the models were evaluated considered the following statistics: adjusted coefficient of determination (R²adj, coefficient of variation (CV and the sum of the squares of deviations (SSD.It was verified in QP and EXP models that small changes on the placement and distribution of the levels caused great changes in the estimation of the OL. The LRP model was deeply influenced by the absence or presence of the level between the response and stabilization phases (change in the straight to plateau. The QRP needed more levels on the response phase and the last level on stabilization phase to estimate correctly the plateau. It was concluded that the OL and the adjust of the models are dependent on the positioning and the number of the levels and the specific characteristics of each model, but levels defined near to the true requirement and not so spaced are better to estimate the OL.

  13. TURBHO - Higher order turbulence modeling for industrial appications. Design document: Module Test Phase (MTP). Software engineering module: Additional physical models; TURBHO. Turbulenzmodellierung hoeherer Ordnung fuer industrielle Anwendungen. Design document: Module Test Phase (MTP). Software engineering module: additional physical models

    Energy Technology Data Exchange (ETDEWEB)

    Grotjans, H.

    1998-04-01

    In the current Software Engineering Module (SEM2) three additional test cases have been investigated, as listed in Chapter 2. For all test cases it has been shown that the computed results are grid independent. This has been done by systematic grid refinement studies. The main objective of the current SEM2 was the verification and validation of the new wall function implementation for the k-{epsilon} mode and the SMC-model. Analytical relations and experimental data have been used for comparison of the computational results. The agreement of the results is good. Therefore, the correct implementation of the new wall function has been demonstrated. As the results in this report have shown, a consistent grid refinement can be done for any test case. This is an important improvement for industrial applications, as no model specific requirements must be considered during grid generation. (orig.)

  14. 78 FR 32224 - Availability of Version 3.1.2 of the Connect America Fund Phase II Cost Model; Additional...

    Science.gov (United States)

    2013-05-29

    ... (202) 863-2893, facsimile (202) 863-2898, or via the Internet at http://www.bcpiweb.com . In addition, the Virtual Workshop may be accessed via the Internet at http://www.fcc.gov/blog/wcb-cost-model... anonymous comments posted during the workshop in reaching decisions regarding the model. Participants should...

  15. The network adjustment aimed for the campaigned gravity survey using a Bayesian approach: methodology and model test

    Science.gov (United States)

    Chen, Shi; Liao, Xu; Ma, Hongsheng; Zhou, Longquan; Wang, Xingzhou; Zhuang, Jiancang

    2017-04-01

    The relative gravimeter, which generally uses zero-length springs as the gravity senor, is still as the first choice in the field of terrestrial gravity measurement because of its efficiency and low-cost. Because the drift rate of instrument can be changed with the time and meter, it is necessary for estimating the drift rate to back to the base or known gravity value stations for repeated measurement at regular hour's interval during the practical survey. However, the campaigned gravity survey for the large-scale region, which the distance of stations is far away from serval or tens kilometers, the frequent back to close measurement will highly reduce the gravity survey efficiency and extremely time-consuming. In this paper, we proposed a new gravity data adjustment method for estimating the meter drift by means of Bayesian statistical interference. In our approach, we assumed the change of drift rate is a smooth function depend on the time-lapse. The trade-off parameters were be used to control the fitting residuals. We employed the Akaike's Bayesian Information Criterion (ABIC) for the estimated these trade-off parameters. The comparison and analysis of simulated data between the classical and Bayesian adjustment show that our method is robust and has self-adaptive ability for facing to the unregularly non-linear meter drift. At last, we used this novel approach to process the realistic campaigned gravity data at the North China. Our adjustment method is suitable to recover the time-varied drift rate function of each meter, and also to detect the meter abnormal drift during the gravity survey. We also defined an alternative error estimation for the inversed gravity value at the each station on the basis of the marginal distribution theory. Acknowledgment: This research is supported by Science Foundation Institute of Geophysics, CEA from the Ministry of Science and Technology of China (Nos. DQJB16A05; DQJB16B07), China National Special Fund for Earthquake

  16. Mechanisms and modeling of the effects of additives on the nitrogen oxides emission

    Science.gov (United States)

    Kundu, Krishna P.; Nguyen, H. Lee; Kang, M. Paul

    1991-01-01

    A theoretical study on the emission of the oxides of nitrogen in the combustion of hydrocarbons is presented. The current understanding of the mechanisms and the rate parameters for gas phase reactions were used to calculate the NO(x) emission. The possible effects of different chemical species on thermal NO(x), on a long time scale were discussed. The mixing of these additives at various stages of combustion were considered and NO(x) concentrations were calculated; effects of temperatures were also considered. The chemicals such as hydrocarbons, H2, CH3OH, NH3, and other nitrogen species were chosen as additives in this discussion. Results of these calculations can be used to evaluate the effects of these additives on the NO(x) emission in the industrial combustion system.

  17. Inclusion of Additional Plant Species and Trait Information in Dynamic Vegetation Modeling of Arctic Tundra and Boreal Forest Ecosystem

    Science.gov (United States)

    Euskirchen, E. S.; Patil, V.; Roach, J.; Griffith, B.; McGuire, A. D.

    2015-12-01

    Dynamic vegetation models (DVMs) have been developed to model the ecophysiological characteristics of plant functional types in terrestrial ecosystems. They have frequently been used to answer questions pertaining to processes such as disturbance, plant succession, and community composition under historical and future climate scenarios. While DVMs have proved useful in these types of applications, it has often been questioned if additional detail, such as including plant dynamics at the species-level and/or including species-specific traits would make these models more accurate and/or broadly applicable. A sub-question associated with this issue is, 'How many species, or what degree of functional diversity, should we incorporate to sustain ecosystem function in modeled ecosystems?' Here, we focus on how the inclusion of additional plant species and trait information may strengthen dynamic vegetation modeling in applications pertaining to: (1) forage for caribou in northern Alaska, (2) above- and belowground carbon storage in the boreal forest and lake margin wetlands of interior Alaska, and (3) arctic tundra and boreal forest leaf phenology. While the inclusion of additional information generally proved valuable in these three applications, this additional detail depends on field data that may not always be available and may also result in increased computational complexity. Therefore, it is important to assess these possible limitations against the perceived need for additional plant species and trait information in the development and application of dynamic vegetation models.

  18. Conceptual performance model for deep in situ recycled pavements with cement and bitumen additives

    CSIR Research Space (South Africa)

    Steyn, WJvdM

    2001-10-01

    Full Text Available structure is monitored together with environmental parameters. Based on this information, and associated laboratory testing data, a model for the performance of these pavements is currently being developed. The model is currently based on the results of APT...

  19. ADDITION TO THE QUASI-BIOLOGICAL MODEL OF RADIOGENIC CANCER MORBIDITY

    Directory of Open Access Journals (Sweden)

    A. Т. Gubin

    2017-01-01

    Full Text Available Object: The purpose was to refine the quasi-biological model of the incidence of radiogenic solid cancer (published by the authors earlier in the journal “Radiation hygiene” to ensure better consistency with the Japanese cohort data and with the ICRP model in part of the description of the effect of age at exposure.Results: Initial presuppositions of a mathematical model was supplemented by the assumption that stem cells, received the “pre-cancerous” defect of DNA, with a higher probability compared to the intact cells follow the path of reproduction but not of differentiation. Structure of the refined model and its properties did not change, but one parameter was added. Analysis of the base mathematical relations of the supplemented model showed that there was no contradiction between the models of radiogenic cancer incidence presented in the Publication 103 ICRP and in the UNSCEAR 2006, despite their external differences.Conclusion: Further work with the model requires the verification of parameter values by comparison with the epidemiological data, primarily with data on the incidence of solid cancers in the Japanese cohort. However, since some of the assumptions of the model, including the new one, are not purely radiobiological, it would require analysis of a wider range of biological and cancer patterns.

  20. Approximating a similarity matrix by a latent class model: A reappraisal of additive fuzzy clustering

    NARCIS (Netherlands)

    Braak, ter C.J.F.; Kourmpetis, Y.I.A.; Kiers, H.A.L.; Bink, M.C.A.M.

    2009-01-01

    Let Q be a given n×n square symmetric matrix of nonnegative elements between 0 and 1, similarities. Fuzzy clustering results in fuzzy assignment of individuals to K clusters. In additive fuzzy clustering, the n×K fuzzy memberships matrix P is found by least-squares approximation of the off-diagonal

  1. Approximating a similarity matrix by a latent class model : A reappraisal of additive fuzzy clustering

    NARCIS (Netherlands)

    ter Braak, Cajo J. F.; Kourmpetis, Yiannis; Kiers, Henk A. L.; Bink, Marco C. A. M.

    2009-01-01

    Let Q be a given n x n square symmetric matrix of nonnegative elements between 0 and 1, e.g. similarities. Fuzzy clustering results in fuzzy assignment of individuals to K clusters. In additive fuzzy clustering, the n x K fuzzy memberships matrix P is found by least-squares approximation of the

  2. Numerical modeling of the strand deposition flow in extrusion-based additive manufacturing

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Serdeczny, Marcin P.; Pedersen, David B.

    2018-01-01

    -based additive manufacturing, as well as the surface roughness of the fabricated part. Under the assumptions of an isothermal Newtonian fluid and a creeping laminar flow, the deposition flow is controlled by two parameters: the gap distance between the extrusion nozzle and the substrate, and the velocity ratio...

  3. Generalized Additive Models for Location Scale and Shape (GAMLSS in R

    Directory of Open Access Journals (Sweden)

    D. Mikis Stasinopoulos

    2007-11-01

    Full Text Available GAMLSS is a general framework for fitting regression type models where the distribution of the response variable does not have to belong to the exponential family and includes highly skew and kurtotic continuous and discrete distribution. GAMLSS allows all the parameters of the distribution of the response variable to be modelled as linear/non-linear or smooth functions of the explanatory variables. This paper starts by defining the statistical framework of GAMLSS, then describes the current implementation of GAMLSS in R and finally gives four different data examples to demonstrate how GAMLSS can be used for statistical modelling.

  4. Normative weight-adjusted models for the median levels of first trimester serum biomarkers for trisomy 21 screening in a specific ethnicity.

    Science.gov (United States)

    Kor-Anantakul, Ounjai; Suntharasaj, Thitima; Suwanrath, Chitkasaem; Hanprasertpong, Tharangrut; Pranpanus, Savitree; Pruksanusak, Ninlapa; Janwadee, Suthiraporn; Geater, Alan

    2017-01-01

    To establish normative weight-adjusted models for the median levels of first trimester serum biomarkers for trisomy 21 screening in southern Thai women, and to compare these reference levels with Caucasian-specific and northern Thai models. A cross-sectional study was conducted in 1,150 normal singleton pregnancy women to determine serum pregnancy-associated plasma protein-A (PAPP-A) and free β-human chorionic gonadotropin (β-hCG) concentrations in women from southern Thailand. The predicted median values were compared with published equations for Caucasians and northern Thai women. The best-fitting regression equations for the expected median serum levels of PAPP-A (mIU/L) and free β- hCG (ng/mL) according to maternal weight (Wt in kg) and gestational age (GA in days) were: [Formula: see text] and [Formula: see text] Both equations were selected with a statistically significant contribution (pmodel, the median values of PAPP-A were higher and the median values of free β-hCG were lower in the southern Thai women. And compared with the northern Thai models, the median values of both biomarkers were lower in southern Thai women. The study has successfully developed maternal-weight- and gestational-age-adjusted median normative models to convert the PAPP-A and free β-hCG levels into their Multiple of Median equivalents in southern Thai women. These models confirmed ethnic differences.

  5. Additive effects of dietary glycotoxins and androgen excess on the kidney of a female rat model

    Directory of Open Access Journals (Sweden)

    Sotiria Palimeri

    2016-06-01

    Conclusions: The above mentioned data suggest that dietary glycotoxins, in combination with increased androgen exposure, exert a more profound negative impact on the kidney of an androgenized female rat model that mimics the metabolic characteristics of polycystic ovary syndrome.

  6. Generalized Additive Models for Location Scale and Shape (GAMLSS) in R

    OpenAIRE

    D. Mikis Stasinopoulos; Robert A. Rigby

    2007-01-01

    GAMLSS is a general framework for fitting regression type models where the distribution of the response variable does not have to belong to the exponential family and includes highly skew and kurtotic continuous and discrete distribution. GAMLSS allows all the parameters of the distribution of the response variable to be modelled as linear/non-linear or smooth functions of the explanatory variables. This paper starts by defining the statistical framework of GAMLSS, then describes the curren...

  7. Multiple imputation with non-additively related variables: Joint-modeling and approximations.

    Science.gov (United States)

    Kim, Soeun; Belin, Thomas R; Sugar, Catherine A

    2016-09-19

    This paper investigates multiple imputation methods for regression models with interacting continuous and binary predictors when continuous variable may be missing. Usual implementations for parametric multiple imputation assume a multivariate normal structure for the variables, which is not satisfied for a binary variable nor its interaction with a continuous variable. To accommodate interactions, missing covariates are multiply imputed from conditional distribution in a manner consistent with the joint model. Alternative imputation methods under multivariate normal assumptions are also considered as candidate approximations and evaluated in a simulation study. The results suggest that the joint modeling procedure performs generally well across a wide range of scenarios and so do the approximation methods that incorporate interactions in the model appropriately by stratification. It is critical to include interactions in the imputation model as failure to do so may result in low coverage and bias. We apply the joint modeling approach and approximation methods in the study of childhood trauma with gender × trauma interaction. © The Author(s) 2016.

  8. Possibilities of Preoperative Medical Models Made by 3D Printing or Additive Manufacturing.

    Science.gov (United States)

    Salmi, Mika

    2016-01-01

    Most of the 3D printing applications of preoperative models have been focused on dental and craniomaxillofacial area. The purpose of this paper is to demonstrate the possibilities in other application areas and give examples of the current possibilities. The approach was to communicate with the surgeons with different fields about their needs related preoperative models and try to produce preoperative models that satisfy those needs. Ten different kinds of examples of possibilities were selected to be shown in this paper and aspects related imaging, 3D model reconstruction, 3D modeling, and 3D printing were presented. Examples were heart, ankle, backbone, knee, and pelvis with different processes and materials. Software types required were Osirix, 3Data Expert, and Rhinoceros. Different 3D printing processes were binder jetting and material extrusion. This paper presents a wide range of possibilities related to 3D printing of preoperative models. Surgeons should be aware of the new possibilities and in most cases help from mechanical engineering side is needed.

  9. In-line monitoring and reverse 3D model reconstruction in additive manufacturing

    DEFF Research Database (Denmark)

    Pedersen, David Bue; Hansen, Hans Nørgaard; Nielsen, Jakob Skov

    2010-01-01

    Additive manufacturing allows for close-to unrestrained geometrical freedom in part design. The ability to manufacture geometries of such complexity is however limited by the fact that it proves difficult to verify tolerances of these parts. Tolerancs of featuress that are inaccessible with tradi......Additive manufacturing allows for close-to unrestrained geometrical freedom in part design. The ability to manufacture geometries of such complexity is however limited by the fact that it proves difficult to verify tolerances of these parts. Tolerancs of featuress that are inaccessible...... with traditional measuring equipment such as Coordinate Measurement Machines (CMM's) can not easily be verified. This paradox is addresses by the proposal of an in-line reverse engineering and 3D reconstruction method that alows for a true to scale reconstruction of a part that is being additivelymanufactures on 3...

  10. Spatial analysis of lung, colorectal, and breast cancer on Cape Cod: An application of generalized additive models to case-control data

    Directory of Open Access Journals (Sweden)

    Aschengrau Ann

    2005-06-01

    Full Text Available Abstract Background The availability of geographic information from cancer and birth defect registries has increased public demands for investigation of perceived disease clusters. Many neighborhood-level cluster investigations are methodologically problematic, while maps made from registry data often ignore latency and many known risk factors. Population-based case-control and cohort studies provide a stronger foundation for spatial epidemiology because potential confounders and disease latency can be addressed. Methods We investigated the association between residence and colorectal, lung, and breast cancer on upper Cape Cod, Massachusetts (USA using extensive data on covariates and residential history from two case-control studies for 1983–1993. We generated maps using generalized additive models, smoothing on longitude and latitude while adjusting for covariates. The resulting continuous surface estimates disease rates relative to the whole study area. We used permutation tests to examine the overall importance of location in the model and identify areas of increased and decreased risk. Results Maps of colorectal cancer were relatively flat. Assuming 15 years of latency, lung cancer was significantly elevated just northeast of the Massachusetts Military Reservation, although the result did not hold when we restricted to residences of longest duration. Earlier non-spatial epidemiology had found a weak association between lung cancer and proximity to gun and mortar positions on the reservation. Breast cancer hot spots tended to increase in magnitude as we increased latency and adjusted for covariates, indicating that confounders were partly hiding these areas. Significant breast cancer hot spots were located near known groundwater plumes and the Massachusetts Military Reservation. Discussion Spatial epidemiology of population-based case-control studies addresses many methodological criticisms of cluster studies and generates new exposure

  11. Modal analysis of additive manufactured carbon fiber reinforced polymer composite: Experiment and modeling

    Science.gov (United States)

    Krasnoveikin, V. A.; Druzhinin, N. V.; Rubtsov, V. E.; Filippov, A. V.; Tarasov, S. Yu.

    2017-12-01

    Additive manufacturing is a promising process to develop the multicomponent polymer-matrix composites. The carbon-reinforced versions of such composites possess a low weight and a high specific strength. Here we present the results of studies of numerical and experimental modal analyses of a framework structure made of a composite material by both aforementioned approaches. The numerical test results and those obtained from the laser Doppler vibrometry show the good agreement for several oscillation modes.

  12. Experiments to Populate and Validate a Processing Model for Polyurethane Foam: Additional Data for Structural Foams

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Giron, Nicholas Henry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    We are developing computational models to help understand manufacturing processes, final properties and aging of structural foam, polyurethane PMDI. Th e resulting model predictions of density and cure gradients from the manufacturing process will be used as input to foam heat transfer and mechanical models. BKC 44306 PMDI-10 and BKC 44307 PMDI-18 are the most prevalent foams used in structural parts. Experiments needed to parameterize models of the reaction kinetics and the equations of motion during the foam blowing stages were described for BKC 44306 PMDI-10 in the first of this report series (Mondy et al. 2014). BKC 44307 PMDI-18 is a new foam that will be used to make relatively dense structural supports via over packing. It uses a different catalyst than those in the BKC 44306 family of foams; hence, we expect that the reaction kineti cs models must be modified. Here we detail the experiments needed to characteriz e the reaction kinetics of BKC 44307 PMDI-18 and suggest parameters for the model based on these experiments. In additi on, the second part of this report describes data taken to provide input to the preliminary nonlinear visco elastic structural response model developed for BKC 44306 PMDI-10 foam. We show that the standard cu re schedule used by KCP does not fully cure the material, and, upon temperature elevation above 150°C, oxidation or decomposition reactions occur that alter the composition of the foam. These findings suggest that achieving a fully cured foam part with this formulation may be not be possible through therma l curing. As such, visco elastic characterization procedures developed for curing thermosets can provide only approximate material properties, since the state of the material continuously evolves during tests.

  13. The biobehavioral family model: testing social support as an additional exogenous variable.

    Science.gov (United States)

    Woods, Sarah B; Priest, Jacob B; Roush, Tara

    2014-12-01

    This study tests the inclusion of social support as a distinct exogenous variable in the Biobehavioral Family Model (BBFM). The BBFM is a biopsychosocial approach to health that proposes that biobehavioral reactivity (anxiety and depression) mediates the relationship between family emotional climate and disease activity. Data for this study included married, English-speaking adult participants (n = 1,321; 55% female; M age = 45.2 years) from the National Comorbidity Survey Replication, a nationally representative epidemiological study of the frequency of mental disorders in the United States. Participants reported their demographics, marital functioning, social support from friends and relatives, anxiety and depression (biobehavioral reactivity), number of chronic health conditions, and number of prescription medications. Confirmatory factor analyses supported the items used in the measures of negative marital interactions, social support, and biobehavioral reactivity, as well as the use of negative marital interactions, friends' social support, and relatives' social support as distinct factors in the model. Structural equation modeling indicated a good fit of the data to the hypothesized model (χ(2)  = 846.04, p = .000, SRMR = .039, CFI = .924, TLI = .914, RMSEA = .043). Negative marital interactions predicted biobehavioral reactivity (β = .38, p social support, inversely (β = -.16, p social support as a predicting factor in the model. © 2014 Family Process Institute.

  14. A new glacial isostatic adjustment model for Antarctica: calibrated and tested using observations of relative sea-level change and present-day uplift rates

    Science.gov (United States)

    Whitehouse, Pippa L.; Bentley, Michael J.; Milne, Glenn A.; King, Matt A.; Thomas, Ian D.

    2012-09-01

    We present a glacial isostatic adjustment (GIA) model for Antarctica. This is driven by a new deglaciation history that has been developed using a numerical ice-sheet model, and is constrained to fit observations of past ice extent. We test the sensitivity of the GIA model to uncertainties in the deglaciation history, and seek earth model parameters that minimize the misfit of model predictions to relative sea-level observations from Antarctica. We find that the relative sea-level predictions are fairly insensitive to changes in lithospheric thickness and lower mantle viscosity, but show high sensitivity to changes in upper mantle viscosity and constrain this value (95 per cent confidence) to lie in the range 0.8-2.0 × 1021 Pa s. Significant misfits at several sites may be due to errors in the deglaciation history, or unmodelled effects of lateral variations in Earth structure. When we compare our GIA model predictions with elastic-corrected GPS uplift rates we find that the predicted rates are biased high (weighted mean bias = 1.8 mm yr-1) and there is a weighted root-mean-square (WRMS) error of 2.9 mm yr-1. In particular, our model systematically over-predicts uplift rates in the Antarctica Peninsula, and we attempt to address this by adjusting the Late Holocene loading history in this region, within the bounds of uncertainty of the deglaciation model. Using this adjusted model the weighted mean bias improves from 1.8 to 1.2 mm yr-1, and the WRMS error is reduced to 2.3 mm yr-1, compared with 4.9 mm yr-1 for ICE-5G v1.2 and 5.0 mm yr-1 for IJ05. Finally, we place spatially variable error bars on our GIA uplift rate predictions, taking into account uncertainties in both the deglaciation history and modelled Earth viscosity structure. This work provides a new GIA correction for the GRACE data in Antarctica, thus permitting more accurate constraints to be placed on current ice-mass change.

  15. [Effects in the adherence treatment and psychological adjustment after the disclosure of HIV/AIDS diagnosis with the "DIRE" clinical model in Colombian children under 17].

    Science.gov (United States)

    Trejos, Ana María; Reyes, Lizeth; Bahamon, Marly Johana; Alarcón, Yolima; Gaviria, Gladys

    2015-08-01

    A study in five Colombian cities in 2006, confirms the findings of other international studies: the majority of HIV-positive children not know their diagnosis, caregivers are reluctant to give this information because they believe that the news will cause emotional distress to the child becoming primary purpose of this study to validate a model of revelation. We implemented a clinical model, referred to as: "DIRE" that hypothetically had normalizing effects on psychological adjustment and adherence to antiretroviral treatment of HIV seropositive children, using a quasi-experimental design. Test were administered (questionnaire to assess patterns of disclosure and non-disclosure of the diagnosis of VIH/SIDA on children in health professionals and participants caregivers, Family Apgar, EuroQol EQ- 5D, MOS Social Support Survey Questionnaire Information treatment for VIH/SIDA and child Symptom Checklist CBCL/6-18 adapted to Latinos) before and after implementation of the model to 31 children (n: 31), 30 caregivers (n: 30) and 41 health professionals. Data processing was performed using the Statistical Package for the Social Science version 21 by applying parametric tests (Friedman) and nonparametric (t Student). No significant differences in adherence to treatment (p=0.392), in the psychological adjustment were found positive significant differences at follow-ups compared to baseline 2 weeks (p: 0.001), 3 months (p: 0.000) and 6 months (p: 0.000). The clinical model demonstrated effectiveness in normalizing of psychological adjustment and maintaining treatment compliance. The process also generated confidence in caregivers and health professionals in this difficult task.

  16. Spatio-temporal precipitation climatology over complex terrain using a censored additive regression model.

    Science.gov (United States)

    Stauffer, Reto; Mayr, Georg J; Messner, Jakob W; Umlauf, Nikolaus; Zeileis, Achim

    2017-06-15

    Flexible spatio-temporal models are widely used to create reliable and accurate estimates for precipitation climatologies. Most models are based on square root transformed monthly or annual means, where a normal distribution seems to be appropriate. This assumption becomes invalid on a daily time scale as the observations involve large fractions of zero observations and are limited to non-negative values. We develop a novel spatio-temporal model to estimate the full climatological distribution of precipitation on a daily time scale over complex terrain using a left-censored normal distribution. The results demonstrate that the new method is able to account for the non-normal distribution and the large fraction of zero observations. The new climatology provides the full climatological distribution on a very high spatial and temporal resolution, and is competitive with, or even outperforms existing methods, even for arbitrary locations.

  17. Finite element modeling of deposition of ceramic material during SLM additive manufacturing

    Directory of Open Access Journals (Sweden)

    Chen Qiang

    2016-01-01

    Full Text Available A three dimensional model for material deposition in Selective Laser Melting (SLM with application to Al2O3-ZrO2 eutectic ceramic is presented. As the material is transparent to laser, dopants are added to increase the heat absorption efficiency. Based on Beer-Lambert law, a volumetric heat source model taking into account the material absorption is derived. The Level Set method with multiphase homogenization is used to track the shape of deposed bead and the thermodynamic is coupled to calculate the melting-solidification path. The shrinkage during consolidation from powder to compact medium is modeled by a compressible Newtonian constitutive law. A semi-implicit formulation of surface tension is used, which permits a stable resolution to capture the gas-liquid interface. The formation of droplets is obtained and slight waves of melt pool are observed. The influence of different process parameters on temperature distribution, melt pool profiles and bead shapes is discussed.

  18. Validation of the internalization of the Model Minority Myth Measure (IM-4) and its link to academic performance and psychological adjustment among Asian American adolescents.

    Science.gov (United States)

    Yoo, Hyung Chol; Miller, Matthew J; Yip, Pansy

    2015-04-01

    There is limited research examining psychological correlates of a uniquely racialized experience of the model minority stereotype faced by Asian Americans. The present study examined the factor structure and fit of the only published measure of the internalization of the model minority myth, the Internalization of the Model Minority Myth Measure (IM-4; Yoo et al., 2010), with a sample of 155 Asian American high school adolescents. We also examined the link between internalization of the model minority myth types (i.e., myth associated with achievement and myth associated with unrestricted mobility) and psychological adjustment (i.e., affective distress, somatic distress, performance difficulty, academic expectations stress), and the potential moderating effect of academic performance (cumulative grade point average). Results suggested the 2-factor model of the IM-4 had an acceptable fit to the data and supported the factor structure using confirmatory factor analyses. Internalizing the model minority myth of achievement related positively to academic expectations stress; however, internalizing the model minority myth of unrestricted mobility related negatively to academic expectations stress, both controlling for gender and academic performance. Finally, academic performance moderated the model minority myth associated with unrestricted mobility and affective distress link and the model minority myth associated with achievement and performance difficulty link. These findings highlight the complex ways in which the model minority myth relates to psychological outcomes. (c) 2015 APA, all rights reserved).

  19. Realistic PIC modelling of laser-plasma interaction: a direct implicit method with adjustable damping and high order weight functions

    International Nuclear Information System (INIS)

    Drouin, M.

    2009-11-01

    This research thesis proposes a new formulation of the relativistic implicit direct method, based on the weak formulation of the wave equation which is solved by means of a Newton algorithm. The first part of this thesis deals with the properties of the explicit particle-in-cell (PIC) methods: properties and limitations of an explicit PIC code, linear analysis of a numerical plasma, numerical heating phenomenon, interest of a higher order interpolation function, and presentation of two applications in high density relativistic laser-plasma interaction. The second and main part of this report deals with adapting the direct implicit method to laser-plasma interaction: presentation of the state of the art, formulating of the direct implicit method, resolution of the wave equation. The third part concerns various numerical and physical validations of the ELIXIRS code: case of laser wave propagation in vacuum, demonstration of the adjustable damping which is a characteristic of the proposed algorithm, influence of space-time discretization on energy conservation, expansion of a thermal plasma in vacuum, two cases of plasma-beam unsteadiness in relativistic regime, and then a case of the overcritical laser-plasma interaction

  20. Methods to adjust for misclassification in the quantiles for the generalized linear model with measurement error in continuous exposures.

    Science.gov (United States)

    Wang, Ching-Yun; Tapsoba, Jean De Dieu; Duggan, Catherine; Campbell, Kristin L; McTiernan, Anne

    2016-05-10

    In many biomedical studies, covariates of interest may be measured with errors. However, frequently in a regression analysis, the quantiles of the exposure variable are often used as the covariates in the regression analysis. Because of measurement errors in the continuous exposure variable, there could be misclassification in the quantiles for the exposure variable. Misclassification in the quantiles could lead to bias estimation in the association between the exposure variable and the outcome variable. Adjustment for misclassification will be challenging when the gold standard variables are not available. In this paper, we develop two regression calibration estimators to reduce bias in effect estimation. The first estimator is normal likelihood-based. The second estimator is linearization-based, and it provides a simple and practical correction. Finite sample performance is examined via a simulation study. We apply the methods to a four-arm randomized clinical trial that tested exercise and weight loss interventions in women aged 50-75 years. Copyright © 2015 John Wiley & Sons, Ltd.

  1. Additive gamma frailty models with applications to competing risks in related individuals

    DEFF Research Database (Denmark)

    Eriksson, Frank; Scheike, Thomas

    2015-01-01

    Epidemiological studies of related individuals are often complicated by the fact that follow-up on the event type of interest is incomplete due to the occurrence of other events. We suggest a class of frailty models with cause-specific hazards for correlated competing events in related individual...

  2. Additional disinfection with a modified salt solution in a root canal model

    NARCIS (Netherlands)

    van der Waal, S.V.; Oonk, C.A.M.; Nieman, S.H.; Wesselink, P.R.; de Soet, J.J.; Crielaard, W.

    2015-01-01

    Objectives The aim of this study is to investigate the disinfecting properties of a modified salt solution (MSS) and calcium hydroxide (Ca(OH)2) in a non-direct-contact ex-vivo model. Methods Seventy-four single-canal roots infected with Enterococcus faecalis were treated with 1% sodium hypochlorite

  3. PULSE: Integrated Parametric Modeling for a Shading System : From Daylight Optimization to Additive Manufacturing

    NARCIS (Netherlands)

    Teeling, M.V.M.T.; Turrin, M.; de Ruiter, P.; Turrin, Michela; Peters, Brady; O'Brien, William; Stouffs, Rudi; Dogan, Timur

    2017-01-01

    This paper presents a parametric approach to an integrated and performance-oriented design, from the conceptual design phase towards materialization. The novelty occurs in the use of parametric models as a way of integrating multidisciplinary design constraints, from daylight optimization to the

  4. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel

    Directory of Open Access Journals (Sweden)

    Emmanuel Moisan

    2015-12-01

    Full Text Available In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part and sonar (for its underwater part scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology.

  5. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel.

    Science.gov (United States)

    Moisan, Emmanuel; Charbonnier, Pierre; Foucher, Philippe; Grussenmeyer, Pierre; Guillemin, Samuel; Koehl, Mathieu

    2015-12-11

    In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology.

  6. AOPs Are Not Additive: On the Biogeo-Optical Modeling of the Diffuse Attenuation Coefficient

    Directory of Open Access Journals (Sweden)

    Zhongping Lee

    2018-01-01

    Full Text Available Commonly we see the diffuse attenuation coefficient of downwelling irradiance (Kd expressed as a sum of the contributions of various constituents. We show here that, both theoretically and numerically, because Kd is an apparent optical property (AOP, this approach is not consistent with radiative transfer. We further advocate the application of models of Kd developed in past decades that are not only consistent with radiative transfer but also provide more accurate estimates, in particular for coastal turbid waters.

  7. A longitudinal examination of the Adaptation to Poverty-Related Stress Model: predicting child and adolescent adjustment over time.

    Science.gov (United States)

    Wadsworth, Martha E; Rindlaub, Laura; Hurwich-Reiss, Eliana; Rienks, Shauna; Bianco, Hannah; Markman, Howard J

    2013-01-01

    This study tests key tenets of the Adaptation to Poverty-related Stress Model. This model (Wadsworth, Raviv, Santiago, & Etter, 2011 ) builds on Conger and Elder's family stress model by proposing that primary control coping and secondary control coping can help reduce the negative effects of economic strain on parental behaviors central to the family stress model, namely, parental depressive symptoms and parent-child interactions, which together can decrease child internalizing and externalizing problems. Two hundred seventy-five co-parenting couples with children between the ages of 1 and 18 participated in an evaluation of a brief family strengthening intervention, aimed at preventing economic strain's negative cascade of influence on parents, and ultimately their children. The longitudinal path model, analyzed at the couple dyad level with mothers and fathers nested within couple, showed very good fit, and was not moderated by child gender or ethnicity. Analyses revealed direct positive effects of primary control coping and secondary control coping on mothers' and fathers' depressive symptoms. Decreased economic strain predicted more positive father-child interactions, whereas increased secondary control coping predicted less negative mother-child interactions. Positive parent-child interactions, along with decreased parent depression and economic strain, predicted child internalizing and externalizing over the course of 18 months. Multiple-group models analyzed separately by parent gender revealed, however, that child age moderated father effects. Findings provide support for the adaptation to poverty-related stress model and suggest that prevention and clinical interventions for families affected by poverty-related stress may be strengthened by including modules that address economic strain and efficacious strategies for coping with strain.

  8. Investigating the prostate specific antigen, body mass index and age relationship: is an age-BMI-adjusted PSA model clinically useful?

    Science.gov (United States)

    Harrison, Sean; Tilling, Kate; Turner, Emma L; Lane, J Athene; Simpkin, Andrew; Davis, Michael; Donovan, Jenny; Hamdy, Freddie C; Neal, David E; Martin, Richard M

    2016-12-01

    Previous studies indicate a possible inverse relationship between prostate-specific antigen (PSA) and body mass index (BMI), and a positive relationship between PSA and age. We investigated the associations between age, BMI, PSA, and screen-detected prostate cancer to determine whether an age-BMI-adjusted PSA model would be clinically useful for detecting prostate cancer. Cross-sectional analysis nested within the UK ProtecT trial of treatments for localized cancer. Of 18,238 men aged 50-69 years, 9,457 men without screen-detected prostate cancer (controls) and 1,836 men with prostate cancer (cases) met inclusion criteria: no history of prostate cancer or diabetes; PSA PSA, age, and BMI in all men, controlling for prostate cancer status. In the 11,293 included men, the median PSA was 1.2 ng/ml (IQR: 0.7-2.6); mean age 61.7 years (SD 4.9); and mean BMI 26.8 kg/m 2 (SD 3.7). There were a 5.1% decrease in PSA per 5 kg/m 2 increase in BMI (95% CI 3.4-6.8) and a 13.6% increase in PSA per 5-year increase in age (95% CI 12.0-15.1). Interaction tests showed no evidence for different associations between age, BMI, and PSA in men above and below 3.0 ng/ml (all p for interaction >0.2). The age-BMI-adjusted PSA model performed as well as an age-adjusted model based on National Institute for Health and Care Excellence (NICE) guidelines at detecting prostate cancer. Age and BMI were associated with small changes in PSA. An age-BMI-adjusted PSA model is no more clinically useful for detecting prostate cancer than current NICE guidelines. Future studies looking at the effect of different variables on PSA, independent of their effect on prostate cancer, may improve the discrimination of PSA for prostate cancer.

  9. How Do I Deal with Depression and Adjustment to My Spinal Cord Injury?

    Medline Plus

    Full Text Available ... request a peer mentor . Additionally, the Reeve Foundation maintains fact sheets on adjustment and depression with resources ... organizations, including: Model Systems Knowledge Translation Center (MSKTC) maintains factsheets on a number of topics, including depression ...

  10. An explanation for the multiplicative and the additive dose-effect relationship with the single-hit model

    International Nuclear Information System (INIS)

    Kottbauer, M.M.; Fleck, C.M.; Schoellnberger, H.

    1997-01-01

    For solid tumors and for leukemia the excess cancer rate after a single radiation dose D is different. The multiplicative model describes the excess solid tumor probability rate which is proportional to the background rate of cancer and dependent on dose D. The additive model describes the excess probability rate for leukaemia which is proportional to the dose D but unrelated to the spontaneous rate of cancer. A second great difference between the two models is the duration of the increased cancer probability rate. The multiplicative mode predicts that the additional cancer risk persist the whole lifetime after exposure and the additive model predicts excess risk over a period of time. With the Single-hit model (SHM) which is a multistage cancer model both dose-response relationships can be described. It will be shown that only small differences in the derivation will lead to the different relationships. We then analyze the incidence data of leukemia (1950-1987) and of all solid tumors (1958-1987) of the atomic bomb survivors. (author)

  11. Modeling the Stereoselectivity of the β-Amino Alcohol Promoted Addition of Dialkylzinc to Aldehydes

    DEFF Research Database (Denmark)

    Rasmussen, Torben; Norrby, Per-Ola

    2003-01-01

    The title reaction has been modeled by a Q2MM force field, allowing for rapid evaluation of several thousand TS conformations. For ten experimental systems taken from the literature, the pathway leading to the major enantiomer has been identified. Furthermore, several possible contributions...... to the minor enantiomer have been investigated, providing an identification of the reasons for the sometimes moderate enantioselectivity of the title reaction, and allowing for future rational improvement of existing ligands. The favored pathways to the minor enantiomer, which must be blocked for significant...

  12. Detection Procedure for a Single Additive Outlier and Innovational Outlier in a Bilinear Model

    Directory of Open Access Journals (Sweden)

    Azami Zaharim

    2007-01-01

    Full Text Available A single outlier detection procedure for data generated from BL(1,1,1,1 models is developed. It is carried out in three stages. Firstly, the measure of impact of an IO and AO denoted by IO ω , AO ω , respectively are derived based on least squares method. Secondly, test statistics and test criteria are defined for classifying an observation as an outlier of its respective type. Finally, a general single outlier detection procedure is presented to distinguish a particular type of outlier at a time point t.

  13. Normative weight-adjusted models for the median levels of first trimester serum biomarkers for trisomy 21 screening in a specific ethnicity.

    Directory of Open Access Journals (Sweden)

    Ounjai Kor-Anantakul

    Full Text Available To establish normative weight-adjusted models for the median levels of first trimester serum biomarkers for trisomy 21 screening in southern Thai women, and to compare these reference levels with Caucasian-specific and northern Thai models.A cross-sectional study was conducted in 1,150 normal singleton pregnancy women to determine serum pregnancy-associated plasma protein-A (PAPP-A and free β-human chorionic gonadotropin (β-hCG concentrations in women from southern Thailand. The predicted median values were compared with published equations for Caucasians and northern Thai women.The best-fitting regression equations for the expected median serum levels of PAPP-A (mIU/L and free β- hCG (ng/mL according to maternal weight (Wt in kg and gestational age (GA in days were: [Formula: see text] and [Formula: see text] Both equations were selected with a statistically significant contribution (p< 0.05. Compared with the Caucasian model, the median values of PAPP-A were higher and the median values of free β-hCG were lower in the southern Thai women. And compared with the northern Thai models, the median values of both biomarkers were lower in southern Thai women.The study has successfully developed maternal-weight- and gestational-age-adjusted median normative models to convert the PAPP-A and free β-hCG levels into their Multiple of Median equivalents in southern Thai women. These models confirmed ethnic differences.

  14. Modeling the Influence of Process Parameters and Additional Heat Sources on Residual Stresses in Laser Cladding

    Science.gov (United States)

    Brückner, F.; Lepski, D.; Beyer, E.

    2007-09-01

    In laser cladding thermal contraction of the initially liquid coating during cooling causes residual stresses and possibly cracks. Preweld or postweld heating using inductors can reduce the thermal strain difference between coating and substrate and thus reduce the resulting stress. The aim of this work is to better understand the influence of various thermometallurgical and mechanical phenomena on stress evolution and to optimize the induction-assisted laser cladding process to get crack-free coatings of hard materials at high feed rates. First, an analytical one-dimensional model is used to visualize the most important features of stress evolution for a Stellite coating on a steel substrate. For more accurate studies, laser cladding is simulated including the powder-beam interaction, the powder catchment by the melt pool, and the self-consistent calculation of temperature field and bead shape. A three-dimensional finite element model and the required equivalent heat sources are derived from the results and used for the transient thermomechanical analysis, taking into account phase transformations and the elastic-plastic material behavior with strain hardening. Results are presented for the influence of process parameters such as feed rate, heat input, and inductor size on the residual stresses at a single bead of Stellite coatings on steel.

  15. Additive SMILES-Based Carcinogenicity Models: Probabilistic Principles in the Search for Robust Predictions

    Directory of Open Access Journals (Sweden)

    Emilio Benfenati

    2009-07-01

    Full Text Available Optimal descriptors calculated with the simplified molecular input line entry system (SMILES have been utilized in modeling of carcinogenicity as continuous values (logTD50. These descriptors can be calculated using correlation weights of SMILES attributes calculated by the Monte Carlo method. A considerable subset of these attributes includes rare attributes. The use of these rare attributes can lead to overtraining. One can avoid the influence of the rare attributes if their correlation weights are fixed to zero. A function, limS, has been defined to identify rare attributes. The limS defines the minimum number of occurrences in the set of structures of the training (subtraining set, to accept attributes as usable. If an attribute is present less than limS, it is considered “rare”, and thus not used. Two systems of building up models were examined: 1. classic training-test system; 2. balance of correlations for the subtraining and calibration sets (together, they are the original training set: the function of the calibration set is imitation of a preliminary test set. Three random splits into subtraining, calibration, and test sets were analysed. Comparison of abovementioned systems has shown that balance of correlations gives more robust prediction of the carcinogenicity for all three splits (split 1: rtest2=0.7514, stest=0.684; split 2: rtest2=0.7998, stest=0.600; split 3: rtest2=0.7192, stest=0.728.

  16. Use of Angle Model to Understand Addition and Subtraction of Fractions

    Directory of Open Access Journals (Sweden)

    Muzwangowenyu Mukwambo

    2018-02-01

    Full Text Available Learners in lower primary and even some in upper primary grades grapple to perform mathematical operations which involve fractions. Failure to solve these mathematical operations creates a gap in the teaching and learning processes of mathematics. We opine that this is attributed to use of traditional mathematical approaches of teaching and learning (TMATL of operations of fraction. With the hope of engaging the reformed mathematical approach of teaching and learning (RMATL this study investigated the following: How can trainee teachers use the angle model in RMATL operations of fractions? What are the perceptions of trainee teachers in the use of the angle model which engages RMATL to teach the operations of fractions? With the goal to fill the mentioned gap in which learners struggle to perform operations involving fractions, we observed and analysed worksheets on operation with fractions students wrote. Observations and interviews with trainee teachers of lower primary revealed poor performance in problems related to operations with fractions. Observed patterns supported by cognitivism revealed that invented methods or strategies on which RMATL is anchored are suitable enough to engage learner–centred teaching and learning which can prevent the abstractness of the concept of operations with fractions.

  17. A novel model for through-silicon via (TSV) filling process simulation considering three additives and current density effect

    Science.gov (United States)

    Wang, Fuliang; Zhao, Zhipeng; Wang, Feng; Wang, Yan; Nie, Nantian

    2017-12-01

    Through-silicon via (TSV) filling by electrochemical deposition is still a challenge for 3D IC packaging, and three-component additive systems (accelerator, suppressor, and leveler) were commonly used in the industry to achieve void-free filling. However, models considering three additive systems and the current density effect have not been fully studied. In this paper, a novel three-component model was developed to study the TSV filling mechanism and process, where the interaction behavior of the three additives (accelerator, suppressor, and leveler) were considered, and the adsorption, desorption, and consumption coefficient of the three additives were changed with the current density. Based on this new model, the three filling types (seam void, ‘V’ shape, and key hole) were simulated under different current density conditions, and the filling results were verified by experiments. The effect of the current density on the copper ion concentration, additives surface coverage, and local current density distribution during the TSV filling process were obtained. Based on the simulation and experimental results, the diffusion–adsorption–desorption–consumption competition behavior between the suppressor, the accelerator, and the leveler were discussed. The filling mechanisms under different current densities were also analyzed.

  18. Synthesis, Characterization, Molecular Modeling, and DNA Interaction Studies of Copper Complex Containing Food Additive Carmoisine Dye.

    Science.gov (United States)

    Shahabadi, Nahid; Akbari, Alireza; Jamshidbeigi, Mina; Khodarahmi, Reza

    2016-06-02

    A copper complex of carmoisine dye; [Cu(carmoisine)2(H2O)2]; was synthesized and characterized by using physico-chemical and spectroscopic methods. The binding of this complex with calf thymus (ct) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, and viscosity measurements. UV-vis results confirmed that the Cu complex interacted with DNA to form a ground-state complex and the observed binding constant (2× 10(4) M(-1)) is more in keeping with the groove bindings with DNA. Furthermore, the viscosity measurement result showed that the addition of complex causes no significant change on DNA viscosity and it indicated that the intercalation mode is ruled out. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the reaction. The results of circular dichroism (CD) suggested that the complex can change the conformation of DNA from B-like form toward A-like conformation. The cytotoxicity studies of the carmoisine dye and its copper complex indicated that both of them had anticancer effects on HT-29 (colon cancer) cell line and they may be new candidates for treatment of the colon cancer.

  19. The Job Demands-Resources Model: An Analysis of Additive and Joint Effects of Demands and Resources

    Science.gov (United States)

    Hu, Qiao; Schaufeli, Wilmar B.; Taris, Toon W.

    2011-01-01

    The present study investigated the additive, synergistic, and moderating effects of job demands and job resources on well-being (burnout and work engagement) and organizational outcomes, as specified by the Job Demands-Resources (JD-R) model. A survey was conducted among two Chinese samples: 625 blue collar workers and 761 health professionals. A…

  20. Should scientists be required to use a model-based solution to adjust for possible distance-based detectability bias?

    Science.gov (United States)

    Hutto, Richard L

    2016-07-01

    The most popular method used to gain an understanding of population trends or of differences in bird abundance among land condition categories is to use information derived from point counts. Unfortunately, various factors can affect one's ability to detect birds, and those factors need to be controlled or accounted for so that any difference in one's index among time periods or locations is an accurate reflection of differences in bird abundance and not differences in detectability. Avian ecologists could use appropriately sized fixed-area surveys to minimize the chance that they might be deceived by distance-based detectability bias, but the current method of choice is to use a modeling approach that allows one to account for distance-based bias by modeling the effects of distance on detectability or occupancy. I challenge the idea that modeling is the best approach to account for distance-based effects on the detectability of birds because the most important distance-based modeling assumptions can never be met. The use of a fixed-area survey method to generate an index of abundance is the simplest way to control for distance-based detectability bias and should not be universally condemned or be the basis for outright rejection in the publication process. © 2016 by the Ecological Society of America.

  1. Risk-adjusted capitation based on the Diagnostic Cost Group Model: an empirical evaluation with health survey information

    NARCIS (Netherlands)

    L.M. Lamers (Leida)

    1999-01-01

    textabstractOBJECTIVE: To evaluate the predictive accuracy of the Diagnostic Cost Group (DCG) model using health survey information. DATA SOURCES/STUDY SETTING: Longitudinal data collected for a sample of members of a Dutch sickness fund. In the Netherlands the sickness

  2. Functional Resilience and Response to a Dietary Additive (Kefir in Models of Foregut and Hindgut Microbial Fermentation In Vitro

    Directory of Open Access Journals (Sweden)

    Gabriel de la Fuente

    2017-06-01

    Full Text Available Stability in gut ecosystems is an important area of study that impacts on the use of additives and is related with several pathologies. Kefir is a fermented milk drink made with a consortium of yeast and bacteria as a fermentation starter, of which the use as additive in companion and livestock animals has increased in the last few years. To investigate the effect of kefir milk on foregut and hindgut digestive systems, an in vitro approach was followed. Either rumen fluid or horse fecal contents were used as a microbial inoculate and the inclusion of kefir (fresh, autoclaved, or pasteurized was tested. Gas production over 72 h of incubation was recorded and pH, volatile fatty acids (VFAs, lactate and ammonia concentration as well as lactic acid (LAB and acetic acid bacteria, and yeast total numbers were also measured. Both direct and indirect (by subtracting their respective blanks effects were analyzed and a multivariate analysis was performed to compare foregut and hindgut fermentation models. Addition of kefir boosted the fermentation by increasing molar concentration of VFAs and ammonia and shifting the Acetate to Propionate ratio in both models but heat processing techniques like pasteurization or autoclaving influenced the way the kefir is fermented and reacts with the present microbiota. In terms of comparison between both models, the foregut model seems to be less affected by the inclusion of Kefir than the hindgut model. In terms of variability in the response, the hindgut model appeared to be more variable than the foregut model in the way that it reacted indirectly to the addition of different types of kefir.

  3. Functional Resilience and Response to a Dietary Additive (Kefir) in Models of Foregut and Hindgut Microbial FermentationIn Vitro.

    Science.gov (United States)

    de la Fuente, Gabriel; Jones, Eleanor; Jones, Shann; Newbold, Charles J

    2017-01-01

    Stability in gut ecosystems is an important area of study that impacts on the use of additives and is related with several pathologies. Kefir is a fermented milk drink made with a consortium of yeast and bacteria as a fermentation starter, of which the use as additive in companion and livestock animals has increased in the last few years. To investigate the effect of kefir milk on foregut and hindgut digestive systems, an in vitro approach was followed. Either rumen fluid or horse fecal contents were used as a microbial inoculate and the inclusion of kefir (fresh, autoclaved, or pasteurized) was tested. Gas production over 72 h of incubation was recorded and pH, volatile fatty acids (VFAs), lactate and ammonia concentration as well as lactic acid (LAB) and acetic acid bacteria, and yeast total numbers were also measured. Both direct and indirect (by subtracting their respective blanks) effects were analyzed and a multivariate analysis was performed to compare foregut and hindgut fermentation models. Addition of kefir boosted the fermentation by increasing molar concentration of VFAs and ammonia and shifting the Acetate to Propionate ratio in both models but heat processing techniques like pasteurization or autoclaving influenced the way the kefir is fermented and reacts with the present microbiota. In terms of comparison between both models, the foregut model seems to be less affected by the inclusion of Kefir than the hindgut model. In terms of variability in the response, the hindgut model appeared to be more variable than the foregut model in the way that it reacted indirectly to the addition of different types of kefir.

  4. The dilution model: how additional goals undermine the perceived instrumentality of a shared path.

    Science.gov (United States)

    Zhang, Ying; Fishbach, Ayelet; Kruglanski, Arie W

    2007-03-01

    Six experiments tested a dilution model of self-regulation, whereby increasing the number of goals (e.g., building muscles and losing weight) that a single means (e.g., exercising) can satisfy reduces the perception of its instrumentality with respect to each goal. The authors found that an increase in the number of simultaneous, salient goals that can be satisfied via a single means weakens the associative strength between that means and each individual goal, and as a result, individuals perceive the means as less effective for the attainment of each goal. Consequently, means that are connected to multiple (vs. single) goals are less likely to be chosen and pursued when only one of these goals is activated. 2007 APA, all rights reserved

  5. Adequacy and adjustment of electromechanical elements of a X radiation generator for automation of system of additional filtration; Adequacao e ajuste dos elementos eletromecanicos de um gerador de radiacao X para automacao do sistema de filtracao adicional

    Energy Technology Data Exchange (ETDEWEB)

    Alves Junior, Iremar; Santos, Lucas dos; Potiens, Maria da Penha A.; Vivolo, Vitor, E-mail: iremarjr@usp.b, E-mail: lucas.se@usp.b, E-mail: mppalbu@ipen.b, E-mail: vivolo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-10-26

    This paper dimensioned the filter wheel components and the adequacy of additional filtrations for the implantation of the OTW automated system with complete replacement of previous used filtration by new set of machine-made filters to be used as the qualities already implanted at the Instrument Calibration Laboratory of the IPEN, Sao Paulo, Brazil. In the sequence, it was performed the measurements of kerma i the air in each quality to be used as reference values

  6. Modeling, Simulation, Additive Manufacturing, and Experimental Evaluation of Solid and Porous NiTi

    Science.gov (United States)

    Taheri Andani, Mohsen

    In recent years, shape memory alloys (SMAs) have entered a wide range of engineering applications in fields such as aerospace and medical applications. Nickel-titanium (NiTi) is the most commonly used SMAs due to its excellent functional characteristics (shape memory effect and superelasticity behavior). These properties are based on a solid-solid phase transformation between martensite and austenite. Beside these two characteristics, low stiffness, biocompatibility and corrosion properties of NiTi make it an attractive candidate for biomedical applications (e.g., bone plates, bone screws, and vascular stents). It is well know that manufacturing and processing of NiTi is very challenging. The functional properties of NiTi are significantly affected by the impurity level and due to the high titanium content, NiTi are highly reactive. Therefore, high temperature processed parts through methods such as melting and casting which result in increased impurity levels have inadequate structural and functional properties. Furthermore, high ductility and elasticity of NiTi, adhesion, work hardening and spring back effects make machining quite challenging. These unfavorable effects for machining cause significant tool wear along with decreasing the quality of work piece. Recently, additive manufacturing (AM) has gained significant attention for manufacturing NiTi. Since AM can create a part directly from CAD data, it is predicted that AM can overcome most of the manufacturing difficulties. This technique provides the possibility of fabricating highly complex parts, which cannot be processed by any other methods. Curved holes, designed porosity, and lattice like structures are some examples of mentioned complex parts. This work investigates manufacturing superelastic NiTi by selective laser melting (SLM) technique (using PXM by Phenix/3D Systems). An extended experimental study is conducted on the effect of subsequent heat treatments with different aging conditions on phase

  7. Improving pharmacy counselling skills: an interdisciplinary model of support for students with English as an additional language.

    Science.gov (United States)

    Kokkinn, Beverley; Stupans, Ieva

    2011-12-01

    The pilot project, described in this paper, targeted English as an additional language (EAL) students to facilitate their development of patient counselling communication skills. An interdisciplinary content-based model was developed drawing on an interactional sociolinguistic framework to map language use valued in pharmacy counselling. Evaluation included analysis of successive self-assessments and surveys of students, surveys of teaching staff and final test results. Evaluation indicated that the interdisciplinary model was highly successful in improving EAL students' competency in pharmacy counselling. The model may have possible wider application for education in health professional programmes. © 2011 The Authors. IJPP © 2011 Royal Pharmaceutical Society.

  8. Tree Biomass Allocation and Its Model Additivity for Casuarina equisetifolia in a Tropical Forest of Hainan Island, China

    Science.gov (United States)

    Xue, Yang; Yang, Zhongyang; Wang, Xiaoyan; Lin, Zhipan; Li, Dunxi; Su, Shaofeng

    2016-01-01

    Casuarina equisetifolia is commonly planted and used in the construction of coastal shelterbelt protection in Hainan Island. Thus, it is critical to accurately estimate the tree biomass of Casuarina equisetifolia L. for forest managers to evaluate the biomass stock in Hainan. The data for this work consisted of 72 trees, which were divided into three age groups: young forest, middle-aged forest, and mature forest. The proportion of biomass from the trunk significantly increased with age (Pbiomass of the branch and leaf decreased, and the biomass of the root did not change. To test whether the crown radius (CR) can improve biomass estimates of C. equisetifolia, we introduced CR into the biomass models. Here, six models were used to estimate the biomass of each component, including the trunk, the branch, the leaf, and the root. In each group, we selected one model among these six models for each component. The results showed that including the CR greatly improved the model performance and reduced the error, especially for the young and mature forests. In addition, to ensure biomass additivity, the selected equation for each component was fitted as a system of equations using seemingly unrelated regression (SUR). The SUR method not only gave efficient and accurate estimates but also achieved the logical additivity. The results in this study provide a robust estimation of tree biomass components and total biomass over three groups of C. equisetifolia. PMID:27002822

  9. Tree Biomass Allocation and Its Model Additivity for Casuarina equisetifolia in a Tropical Forest of Hainan Island, China.

    Science.gov (United States)

    Xue, Yang; Yang, Zhongyang; Wang, Xiaoyan; Lin, Zhipan; Li, Dunxi; Su, Shaofeng

    2016-01-01

    Casuarina equisetifolia is commonly planted and used in the construction of coastal shelterbelt protection in Hainan Island. Thus, it is critical to accurately estimate the tree biomass of Casuarina equisetifolia L. for forest managers to evaluate the biomass stock in Hainan. The data for this work consisted of 72 trees, which were divided into three age groups: young forest, middle-aged forest, and mature forest. The proportion of biomass from the trunk significantly increased with age (Pbiomass of the branch and leaf decreased, and the biomass of the root did not change. To test whether the crown radius (CR) can improve biomass estimates of C. equisetifolia, we introduced CR into the biomass models. Here, six models were used to estimate the biomass of each component, including the trunk, the branch, the leaf, and the root. In each group, we selected one model among these six models for each component. The results showed that including the CR greatly improved the model performance and reduced the error, especially for the young and mature forests. In addition, to ensure biomass additivity, the selected equation for each component was fitted as a system of equations using seemingly unrelated regression (SUR). The SUR method not only gave efficient and accurate estimates but also achieved the logical additivity. The results in this study provide a robust estimation of tree biomass components and total biomass over three groups of C. equisetifolia.

  10. Tree Biomass Allocation and Its Model Additivity for Casuarina equisetifolia in a Tropical Forest of Hainan Island, China.

    Directory of Open Access Journals (Sweden)

    Yang Xue

    Full Text Available Casuarina equisetifolia is commonly planted and used in the construction of coastal shelterbelt protection in Hainan Island. Thus, it is critical to accurately estimate the tree biomass of Casuarina equisetifolia L. for forest managers to evaluate the biomass stock in Hainan. The data for this work consisted of 72 trees, which were divided into three age groups: young forest, middle-aged forest, and mature forest. The proportion of biomass from the trunk significantly increased with age (P<0.05. However, the biomass of the branch and leaf decreased, and the biomass of the root did not change. To test whether the crown radius (CR can improve biomass estimates of C. equisetifolia, we introduced CR into the biomass models. Here, six models were used to estimate the biomass of each component, including the trunk, the branch, the leaf, and the root. In each group, we selected one model among these six models for each component. The results showed that including the CR greatly improved the model performance and reduced the error, especially for the young and mature forests. In addition, to ensure biomass additivity, the selected equation for each component was fitted as a system of equations using seemingly unrelated regression (SUR. The SUR method not only gave efficient and accurate estimates but also achieved the logical additivity. The results in this study provide a robust estimation of tree biomass components and total biomass over three groups of C. equisetifolia.

  11. An Equiratio Mixture Model for non-additive components: a case study for aspartame/acesulfame-K mixtures.

    Science.gov (United States)

    Schifferstein, H N

    1996-02-01

    The Equiratio Mixture Model predicts the psychophysical function for an equiratio mixture type on the basis of the psychophysical functions for the unmixed components. The model reliably estimates the sweetness of mixtures of sugars and sugar-alcohols, but is unable to predict intensity for aspartame/sucrose mixtures. In this paper, the sweetness of aspartame/acesulfame-K mixtures in aqueous and acidic solutions is investigated. These two intensive sweeteners probably do not comply with the model's original assumption of sensory dependency among components. However, they reveal how the Equiratio Mixture Model could be modified to describe and predict mixture functions for non-additive substances. To predict equiratio functions for all similar tasting substances, a new Equiratio Mixture Model should yield accurate predictions for components eliciting similar intensities at widely differing concentration levels, and for substances exhibiting hypo- or hyperadditivity. In addition, it should be able to correct violations of Stevens's power law. These three problems are resolved in a model that uses equi-intense units as the measure of physical concentration. An interaction index in the formula for the constant accounts for the degree of interaction between mixture components. Deviations from the power law are corrected by a nonlinear response output transformation, assuming a two-stage model of psychophysical judgment.

  12. Concentration addition and independent action model: Which is better in predicting the toxicity for metal mixtures on zebrafish larvae.

    Science.gov (United States)

    Gao, Yongfei; Feng, Jianfeng; Kang, Lili; Xu, Xin; Zhu, Lin

    2018-01-01

    The joint toxicity of chemical mixtures has emerged as a popular topic, particularly on the additive and potential synergistic actions of environmental mixtures. We investigated the 24h toxicity of Cu-Zn, Cu-Cd, and Cu-Pb and 96h toxicity of Cd-Pb binary mixtures on the survival of zebrafish larvae. Joint toxicity was predicted and compared using the concentration addition (CA) and independent action (IA) models with different assumptions in the toxic action mode in toxicodynamic processes through single and binary metal mixture tests. Results showed that the CA and IA models presented varying predictive abilities for different metal combinations. For the Cu-Cd and Cd-Pb mixtures, the CA model simulated the observed survival rates better than the IA model. By contrast, the IA model simulated the observed survival rates better than the CA model for the Cu-Zn and Cu-Pb mixtures. These findings revealed that the toxic action mode may depend on the combinations and concentrations of tested metal mixtures. Statistical analysis of the antagonistic or synergistic interactions indicated that synergistic interactions were observed for the Cu-Cd and Cu-Pb mixtures, non-interactions were observed for the Cd-Pb mixtures, and slight antagonistic interactions for the Cu-Zn mixtures. These results illustrated that the CA and IA models are consistent in specifying the interaction patterns of binary metal mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Recent Additions in the Modeling Capabilities of an Open-Source Wave Energy Converter Design Tool: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, N.; Lawson, M.; Yu, Y. H.

    2015-04-20

    WEC-Sim is a midfidelity numerical tool for modeling wave energy conversion devices. The code uses the MATLAB SimMechanics package to solve multibody dynamics and models wave interactions using hydrodynamic coefficients derived from frequency-domain boundary-element methods. This paper presents the new modeling features introduced in the latest release of WEC-Sim. The first feature discussed conversion of the fluid memory kernel to a state-space form. This enhancement offers a substantial computational benefit after the hydrodynamic body-to-body coefficients are introduced and the number of interactions increases exponentially with each additional body. Additional features include the ability to calculate the wave-excitation forces based on the instantaneous incident wave angle, allowing the device to weathervane, as well as import a user-defined wave elevation time series. A review of the hydrodynamic theory for each feature is provided and the successful implementation is verified using test cases.

  14. Adjustable link for kinematic mounting systems

    Science.gov (United States)

    Hale, L.C.

    1997-07-01

    An adjustable link for kinematic mounting systems is disclosed. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two. 3 figs.

  15. Addition of glucagon to adrenaline improves hemodynamics in a porcine model of prolonged ventricular fibrillation.

    Science.gov (United States)

    Raffay, Violetta; Chalkias, Athanasios; Lelovas, Pavlos; Karlis, Georgios; Koutsovasilis, Anastasios; Papalois, Apostolos; Jevdjic, Jasna; Fiser, Zlatko; Xanthos, Theodoros

    2014-02-01

    Cardiac arrest is a daunting medical emergency. The aim of the present study was to assess whether the combination of adrenaline and glucagon would improve initial resuscitation success, 48-hour survival, and neurologic outcome compared with adrenaline alone in a porcine model of ventricular fibrillation. Ventricular fibrillation was induced in 20 healthy Landrace/Large White piglets, which were subsequently left untreated for 8 minutes. The animals were randomized to receive adrenaline alone (n = 10, group C) and adrenaline plus glucagon (n = 10, group G). All animals were resuscitated according to the 2010 European Resuscitation Council guidelines. Hemodynamic variables were measured before arrest, during arrest and resuscitation, and during the first 60 minutes after return of spontaneous circulation. Survival and a neurologic alertness score were measured at 48 hours after return of spontaneous circulation. Return of spontaneous circulation was achieved in 8 animals (80%) from group C and 10 animals (100%) from group G (P = .198). A significant gradual increase in coronary perfusion pressure and diastolic aortic pressure over time, which started 1 minute after the onset of cardiopulmonary resuscitation, was observed. Three animals (30%) from group C and 9 animals (90%) from group G survived after 48 hours (P = .006), whereas neurologic examination was significantly better in the animals of group G (P adrenaline improves hemodynamics during resuscitation and early postresuscitation period and may increase survival. © 2013.

  16. An Evaluation of the Adjusted DeLone and McLean Model of Information Systems Success; the case of financial information system in Ferdowsi University of Mashhad

    Directory of Open Access Journals (Sweden)

    Mohammad Lagzian

    2012-07-01

    Full Text Available Assessing the success of information systems within organizations has been identified as one of the most critical subjects of information system management in both public and private organizations. It is therefore important to measure the success of information systems from the user's perspective. The purpose of the current study was to evaluate the degree of information system success by the adjusted DeLone and McLean’s model in the field financial information system (FIS in an Iranian University. The relationships among the dimensions in an extended systems success measurement framework were tested. Data were collected by questionnaire from end-users of a financial information system at Ferdowsi University of Mashhad. The adjusted DeLone and McLean model was contained five variables (system quality, information quality, system use, user satisfaction, and individual impact. The results revealed that system quality was significant predictor of system use, user satisfaction and individual impact. Information quality was also a significant predictor of user satisfaction and individual impact, but not of system use. System use and user satisfaction were positively related to individual impact. The influence of user satisfaction on system use was insignificant

  17. Three dimensional models in uro-oncology: a future built with additive fabrication.

    Science.gov (United States)

    Manning, Todd G; O'Brien, Jonathan S; Christidis, Daniel; Perera, Marlon; Coles-Black, Jasamine; Chuen, Jason; Bolton, Damien M; Lawrentschuk, Nathan

    2018-04-01

    Three-dimensional (3D) printing was invented in 1983 but has only just begun to influence medicine and surgery. Conversion of digital images into physical models demonstrates promise to revolutionize multiple domains of surgery. In the field of uro-oncology, researchers and clinicians have recognized the potential of this technology and are working towards making it an integral part of urological practice. We review current literature regarding 3D printing and other 3D technology in the field of urology. A comprehensive assessment of contemporary literature was performed according to a modified PRISMA analysis for the purposes of this narrative review article. Medical databases that were searched included: Web of Science, EMBASE and Cochrane databases. Articles assessed were limited only to English-language peer-reviewed articles published between 1980 and 2017. The search terms used were "3D", "3-dimensional", "printing", "printing technology", "urology", "surgery". Acceptable articles were reviewed and incorporated for their merit and relevance with preference given for articles with high impact, original research and recent advances. Thirty-five publications were included in final analysis and discussion. The area of 3D printing in Urology shows promising results, but further research is required and cost reduction must occur before clinicians fully embrace its use. As costs continue to decline and diversity of materials continues to expand, research and clinical utilization will increase. Recent advances have demonstrated the potential of this technology in the realms of education and surgical optimization. The generation of personalized organs using 3D printing scaffolding remains the 'holy grail' of this technology.

  18. A lump-integral model based freezing and melting of a bath material onto a cylindrical additive of negligible resistance

    Directory of Open Access Journals (Sweden)

    Singh U.C.

    2013-01-01

    Full Text Available In a theoretical analysis, a lump-integral model for freezing and melting of the bath material onto a cylindrical additive having its thermal resistance negligible with respect to that of the bath is developed. It is regulated by independent nondimensional parameters, namely the Stefan number, St the heat capacity ratio, Cr and the modified conduction factor, Cofm. Series solutions associated with short times for time variant growth of the frozen layer and rise in interface temperature between the additive and the frozen layer are obtained. For all times, numerical solutions concerning the frozen layer growth with its melting and increase in the interface temperature are also found. Time for freezing and melting is estimated for different values of Cr, St and Cofm. It is predicted that for lower total time of freezing and melting Cofm<2 or Cr<1 needs to be maintained. When the bath temperature equals the freezing temperature of the bath material, the model is governed by only Cr and St and gives closed-form expressions for the growth of the frozen layer and the interface temperature. For the interface attaining the freezing temperature of the bath material the maximum thickness of the frozen layer becomes ξmax-√Cr(Cr+St. The model is validated once it is reduced to a problem of heating of the additive without freezing of the bath material onto the additive. Its closed-form solution is exactly the same as that reported in the literature.

  19. Measuring demand for flat water recreation using a two-stage/disequilibrium travel cost model with adjustment for overdispersion and self-selection

    Science.gov (United States)

    McKean, John R.; Johnson, Donn; Taylor, R. Garth

    2003-04-01

    An alternate travel cost model is applied to an on-site sample to estimate the value of flat water recreation on the impounded lower Snake River. Four contiguous reservoirs would be eliminated if the dams are breached to protect endangered Pacific salmon and steelhead trout. The empirical method applies truncated negative binomial regression with adjustment for endogenous stratification. The two-stage decision model assumes that recreationists allocate their time among work and leisure prior to deciding among consumer goods. The allocation of time and money among goods in the second stage is conditional on the predetermined work time and income. The second stage is a disequilibrium labor market which also applies if employers set work hours or if recreationists are not in the labor force. When work time is either predetermined, fixed by contract, or nonexistent, recreationists must consider separate prices and budgets for time and money.

  20. Density prediction and dimensionality reduction of mid-term electricity demand in China: A new semiparametric-based additive model

    International Nuclear Information System (INIS)

    Shao, Zhen; Yang, Shan-Lin; Gao, Fei

    2014-01-01

    Highlights: • A new stationary time series smoothing-based semiparametric model is established. • A novel semiparametric additive model based on piecewise smooth is proposed. • We model the uncertainty of data distribution for mid-term electricity forecasting. • We provide efficient long horizon simulation and extraction for external variables. • We provide stable and accurate density predictions for mid-term electricity demand. - Abstract: Accurate mid-term electricity demand forecasting is critical for efficient electric planning, budgeting and operating decisions. Mid-term electricity demand forecasting is notoriously complicated, since the demand is subject to a range of external drivers, such as climate change, economic development, which will exhibit monthly, seasonal, and annual complex variations. Conventional models are based on the assumption that original data is stable and normally distributed, which is generally insignificant in explaining actual demand pattern. This paper proposes a new semiparametric additive model that, in addition to considering the uncertainty of the data distribution, includes practical discussions covering the applications of the external variables. To effectively detach the multi-dimensional volatility of mid-term demand, a novel piecewise smooth method which allows reduction of the data dimensionality is developed. Besides, a semi-parametric procedure that makes use of bootstrap algorithm for density forecast and model estimation is presented. Two typical cases in China are presented to verify the effectiveness of the proposed methodology. The results suggest that both meteorological and economic variables play a critical role in mid-term electricity consumption prediction in China, while the extracted economic factor is adequate to reveal the potentially complex relationship between electricity consumption and economic fluctuation. Overall, the proposed model can be easily applied to mid-term demand forecasting, and

  1. Modelling the potential impact of a sugar-sweetened beverage tax on stroke mortality, costs and health-adjusted life years in South Africa

    Directory of Open Access Journals (Sweden)

    Mercy Manyema

    2016-05-01

    Full Text Available Abstract Background Stroke poses a growing human and economic burden in South Africa. Excess sugar consumption, especially from sugar-sweetened beverages (SSBs, has been associated with increased obesity and stroke risk. Research shows that price increases for SSBs can influence consumption and modelling evidence suggests that taxing SSBs has the potential to reduce obesity and related diseases. This study estimates the potential impact of an SSB tax on stroke-related mortality, costs and health-adjusted life years in South Africa. Methods A proportional multi-state life table-based model was constructed in Microsoft Excel (2010. We used consumption data from the 2012 South African National Health and Nutrition Examination Survey, previously published own and cross price elasticities of SSBs and energy balance equations to estimate changes in daily energy intake and BMI arising from increased SSB prices. Stroke relative risk, and prevalent years lived with disability estimates from the Global Burden of Disease Study and modelled disease epidemiology estimates from a previous study, were used to estimate the effect of the BMI changes on the burden of stroke. Results Our model predicts that an SSB tax may avert approximately 72 000 deaths, 550 000 stroke-related health-adjusted life years and over ZAR5 billion, (USD400 million in health care costs over 20 years (USD296-576 million. Over 20 years, the number of incident stroke cases may be reduced by approximately 85 000 and prevalent cases by about 13 000. Conclusions Fiscal policy has the potential, as part of a multi-faceted approach, to mitigate the growing burden of stroke in South Africa and contribute to the achievement of the target set by the Department of Health to reduce relative premature mortality (less than 60 years from non-communicable diseases by the year 2020.

  2. The relationship between chronic musculoskeletal pain, anxiety and mindfulness: Adjustments to the Fear-Avoidance Model of Chronic Pain.

    Science.gov (United States)

    Curtin, Katherine B; Norris, Deborah

    2017-10-01

    The Fear-Avoidance Model of Chronic Pain proposed by Vlaeyen and Linton states individuals enter a cycle of chronic pain due to predisposing psychological factors, such as negative affectivity, negative appraisal or anxiety sensitivity. They do not, however, address the closely related concept of anxious rumination. Although Vlaeyen and Linton suggest cognitive-behavioral treatment methods for chronic pain patients who exhibit pain-related fear, they do not consider mindfulness treatments. This cross-sectional study investigated the relationship between chronic musculoskeletal pain (CMP), ruminative anxiety and mindfulness to determine if (1) ruminative anxiety is a risk factor for developing chronic pain and (2) mindfulness is a potential treatment for breaking the cycle of chronic pain. Middle-aged adults ages 35-50 years (N=201) with self-reported CMP were recruited online. Participants completed standardized questionnaires assessing elements of chronic pain, anxiety, and mindfulness. Ruminative anxiety was positively correlated with pain catastrophizing, pain-related fear and avoidance, pain interference, and pain severity but negatively correlated with mindfulness. High ruminative anxiety level predicted significantly higher elements of chronic pain and significantly lower level of mindfulness. Mindfulness significantly predicted variance (R 2 ) in chronic pain and anxiety outcomes. Pain severity, ruminative anxiety, pain catastrophizing, pain-related fear and avoidance, and mindfulness significantly predicted 70.0% of the variance in pain interference, with pain severity, ruminative anxiety and mindfulness being unique predictors. The present study provides insight into the strength and direction of the relationships between ruminative anxiety, mindfulness and chronic pain in a CMP population, demonstrating the unique associations between specific mindfulness factors and chronic pain elements. It is possible that ruminative anxiety and mindfulness should be

  3. Drought mitigation in perennial crops by fertilization and adjustments of regional yield models for future climate variability

    Science.gov (United States)

    Kantola, I. B.; Blanc-Betes, E.; Gomez-Casanovas, N.; Masters, M. D.; Bernacchi, C.; DeLucia, E. H.

    2017-12-01

    Increased variability and intensity of precipitation in the Midwest agricultural belt due to climate change is a major concern. The success of perennial bioenergy crops in replacing maize for bioethanol production is dependent on sustained yields that exceed maize, and the marketing of perennial crops often emphasizes the resilience of perennial agriculture to climate stressors. Land conversion from maize for bioethanol to Miscanthus x giganteus (miscanthus) increases yields and annual evapotranspiration rates (ET). However, establishment of miscanthus also increases biome water use efficiency (the ratio between net ecosystem productivity after harvest and ET), due to greater belowground biomass in miscanthus than in maize or soybean. In 2012, a widespread drought reduced the yield of 5-year-old miscanthus plots in central Illinois by 36% compared to the previous two years. Eddy covariance data indicated continued soil water deficit during the hydrologically-normal growing season in 2013 and miscanthus yield failed to rebound as expected, lagging behind pre-drought yields by an average of 53% over the next three years. In early 2014, nitrogen fertilizer was applied to half of mature (7-year-old) miscanthus plots in an effort to improve yields. In plots with annual post-emergence application of 60 kg ha-1 of urea, peak biomass was 29% greater than unfertilized miscanthus in 2014, and 113% greater in 2015, achieving statistically similar yields to the pre-drought average. Regional-scale models of perennial crop productivity use 30-year climate averages that are inadequate for predicting long-term effects of short-term extremes on perennial crops. Modeled predictions of perennial crop productivity incorporating repeated extreme weather events, observed crop response, and the use of management practices to mitigate water deficit demonstrate divergent effects on predicted yields.

  4. Parameter and State Estimation of an Anaerobic Digestion of Organic Wastes Model with Addition of Stimulating Substances

    Directory of Open Access Journals (Sweden)

    Velislava Lubenova

    2009-03-01

    Full Text Available New control inputs are introduced in the 5th order mass-balance non-linear model of the anaerobic digestion, which reflects the addition of stimulating substances (acetate and glucose. Laboratory experiments have been done with step-wise and pulse changes of these new inputs. On the basis of the step responses of the measured variables (biogas flow rate and acetate concentration in the bioreactor and iterative methodology, involving non-linear optimisation and simulations, the model coefficients have been estimated. The model validity has been proved by another set of experiments. The observation part is built on a two-step structure. One estimator and two observers are designed on the basis of this process model. Their stability has been proved and their performances have been investigated with experimental data and simulations.

  5. Associations between maternal and paternal depressive symptoms and early child behavior problems: Testing a mutually adjusted prospective longitudinal model.

    Science.gov (United States)

    Narayanan, Martina K; Nærde, Ane

    2016-05-15

    While there is substantial empirical work on maternal depression, less is known about how mothers' and fathers' depressive symptoms compare in their association with child behavior problems in early childhood. In particular, few studies have examined unique relationships in the postpartum period by controlling for the other parent, or looked at longitudinal change in either parent's depressive symptoms across the first living years as a predictor of child problems. We examined depressive symptoms in parents at 6, 12, 24, 36 and 48 months following childbirth, and child behavior problems at 48 months. Linear growth curve analysis was used to model parents' initial levels and changes in symptoms across time and their associations with child outcomes. Mothers' depressive symptoms at 6 months predicted behavior problems at 48 months for all syndrome scales, while fathers' did not. Estimates for mothers' symptoms were significantly stronger on all subscales. Change in fathers' depressive symptoms over time was a significantly larger predictor of child aggressive behavior than corresponding change in mothers'. No interaction effects between parents' symptoms on behavior problems appeared, and few child gender differences. Child behavior was assessed once precluding tests for bidirectional effects. We only looked at linear change in parental symptoms. Mothers' postpartum depressive symptoms are a stronger predictor for early child behavior problems than fathers'. Change in fathers' depressive symptoms across this developmental period was uniquely and strongly associated with child aggressive problems, and should therefore be addressed in future research and clinical practice. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Annual Adjustment Factors

    Data.gov (United States)

    Department of Housing and Urban Development — The Department of Housing and Urban Development establishes the rent adjustment factors - called Annual Adjustment Factors (AAFs) - on the basis of Consumer Price...

  7. Evaluation and adjustment of description of denitrification in the DailyDayCent and COUP models based on N2 and N2O laboratory incubation system measurements

    Science.gov (United States)

    Grosz, Balázs; Well, Reinhard; Dannenmann, Michael; Dechow, René; Kitzler, Barbara; Michel, Kerstin; Reent Köster, Jan

    2017-04-01

    data-sets are needed in view of the extreme spatio-temporal heterogeneity of denitrification. DASIM will provide such data based on laboratory incubations including measurement of N2O and N2 fluxes and determination of the relevant drivers. Here, we present how we will use these data to evaluate common biogeochemical process models (DailyDayCent, Coup) with respect to modeled NO, N2O and N2 fluxes from denitrification. The models are used with different settings. The first approximation is the basic "factory" setting of the models. The next step would show the precision in the results of the modeling after adjusting the appropriate parameters from the result of the measurement values and the "factory" results. The better adjustment and the well-controlled input and output measured parameters could provide a better understanding of the probable scantiness of the tested models which will be a basis for future model improvement.

  8. Pre-entry Characteristics, Perceived Social Support, Adjustment and Academic Achievement in First-Year Spanish University Students: A Path Model.

    Science.gov (United States)

    Rodríguez, María Soledad; Tinajero, Carolina; Páramo, María Fernanda

    2017-11-17

    Transition to university is a multifactorial process to which scarce consideration has been given in Spain, despite this being one of the countries with the highest rates of academic failure and attrition within the European Union. The present study proposes an empirical model for predicting Spanish students' academic achievement at university by considering pre-entry characteristics, perceived social support and adaptation to university, in a sample of 300 traditional first-year university students. The findings of the path analysis showed that pre-university achievement and academic and personal-emotional adjustment were direct predictors of academic achievement. Furthermore, gender, parents' education and family support were indirect predictors of academic achievement, mediated by pre-university grades and adjustment to university. The current findings supporting evidence that academic achievement in first-year Spanish students is the cumulative effect of pre-entry characteristics and process variables, key factors that should be taken into account in designing intervention strategies involving families and that establish stronger links between research findings and university policies.

  9. Political violence and child adjustment in Northern Ireland: Testing pathways in a social-ecological model including single-and two-parent families.

    Science.gov (United States)

    Cummings, E Mark; Schermerhorn, Alice C; Merrilees, Christine E; Goeke-Morey, Marcie C; Shirlow, Peter; Cairns, Ed

    2010-07-01

    Moving beyond simply documenting that political violence negatively impacts children, we tested a social-ecological hypothesis for relations between political violence and child outcomes. Participants were 700 mother-child (M = 12.1 years, SD = 1.8) dyads from 18 working-class, socially deprived areas in Belfast, Northern Ireland, including single- and two-parent families. Sectarian community violence was associated with elevated family conflict and children's reduced security about multiple aspects of their social environment (i.e., family, parent-child relations, and community), with links to child adjustment problems and reductions in prosocial behavior. By comparison, and consistent with expectations, links with negative family processes, child regulatory problems, and child outcomes were less consistent for nonsectarian community violence. Support was found for a social-ecological model for relations between political violence and child outcomes among both single- and two-parent families, with evidence that emotional security and adjustment problems were more negatively affected in single-parent families. The implications for understanding social ecologies of political violence and children's functioning are discussed.

  10. Political violence and child adjustment in Northern Ireland: Testing pathways in a social ecological model including single and two-parent families

    Science.gov (United States)

    Cummings, E. Mark; Schermerhorn, Alice C.; Merrilees, Christine E.; Goeke-Morey, Marcie C.; Shirlow, Peter; Cairns, Ed

    2013-01-01

    Moving beyond simply documenting that political violence negatively impacts children, a social ecological hypothesis for relations between political violence and child outcomes was tested. Participants were 700 mother-child (M=12.1years, SD=1.8) dyads from 18 working class, socially deprived areas in Belfast, Northern Ireland, including single- and two-parent families. Sectarian community violence was associated with elevated family conflict and children’s reduced security about multiple aspects of their social environment (i.e., family, parent-child relations, and community), with links to child adjustment problems and reductions in prosocial behavior. By comparison, and consistent with expectations, links with negative family processes, child regulatory problems and child outcomes were less consistent for nonsectarian community violence. Support was found for a social ecological model for relations between political violence and child outcomes among both single and two parent families, with evidence that emotional security and adjustment problems were more negatively affected in single-parent families. The implications for understanding social ecologies of political violence and children’s functioning are discussed. PMID:20604605

  11. Kinematic adjustments to seismic recordings

    Energy Technology Data Exchange (ETDEWEB)

    Telegin, A.N.; Levii, N.V.; Volovik, U.M.

    1981-01-01

    The introduction of kinematic adjustments by adding the displaced blocks is studied theoretically and in test seismograms. The advantage to this method resulting from the weight variation in the trace is demonstrated together with its kinematic drawback. A variation on the displaced block addition method that does not involve realignment of the travel time curves and that has improved amplitude characteristics is proposed.

  12. Glacial Isostatic Adjustment Derived Boundary Conditions for Paleoclimate Simulation: the Refined ICE-6G_D (VM5a) Model and the Dansgaard-Oeschger Oscillation

    Science.gov (United States)

    Peltier, W. R.; Vettoretti, G.; Argus, D. F.

    2017-12-01

    Global models of the glacial isostatic adjustment (GIA) process are designed to fit a wide range of geophysical and geomorphological observations that simultaneously constrain the internal viscoelastic structure of Earths interior and the history of grounded ice thickness variations that has occurred over the most recent ice-age cycle of the Late Quaternary interval of time. The most recent refinement of the ICE-NG (VMX) series of such global models from the University of Toronto, ICE-6G_C (VM5a), has recently been slightly modified insofar as its Antarctic component is concerned to produce a "_D" version of the structure. This has been chosen to provide the boundary conditions for the next round of model-data inter-comparisons in the context of the international Paleoclimate Modeling Inter-comparison Project (PMIP). The output of PMIP will contribute to the Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change which is now under way. A highly significant test of the utility of this latest model has recently been performed that is focused upon the Dansgaard-Oeschger oscillation that was the primary source of climate variability during Marine Isotope Stage 3 (MIS3) of the most recent glacial cycle. By introducing the surface boundary conditions for paleotopography and paleobathymetry, land-sea mask and surface albedo into the NCAR CESM1 coupled climate model configured at full one degree by one degree CMIP5 resolution, together with the appropriate trace gas and orbital insolation forcing, we show that the millennium timescale Dansgard-Oeschger oscillation naturally develops following spin- up of the model into the glacial state.

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

    Science.gov (United States)

    Chirombo, James; Lowe, Rachel; Kazembe, Lawrence

    2014-01-01

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

  14. Using a logic model to evaluate the Kids Together early education inclusion program for children with disabilities and additional needs.

    Science.gov (United States)

    Clapham, Kathleen; Manning, Claire; Williams, Kathryn; O'Brien, Ginger; Sutherland, Margaret

    2017-04-01

    Despite clear evidence that learning and social opportunities for children with disabilities and special needs are more effective in inclusive not segregated settings, there are few known effective inclusion programs available to children with disabilities, their families or teachers in the early years within Australia. The Kids Together program was developed to support children with disabilities/additional needs aged 0-8 years attending mainstream early learning environments. Using a key worker transdisciplinary team model, the program aligns with the individualised package approach of the National Disability Insurance Scheme (NDIS). This paper reports on the use of a logic model to underpin the process, outcomes and impact evaluation of the Kids Together program. The research team worked across 15 Early Childhood Education and Care (ECEC) centres and in home and community settings. A realist evaluation using mixed methods was undertaken to understand what works, for whom and in what contexts. The development of a logic model provided a structured way to explore how the program was implemented and achieved short, medium and long term outcomes within a complex community setting. Kids Together was shown to be a highly effective and innovative model for supporting the inclusion of children with disabilities/additional needs in a range of environments central for early childhood learning and development. The use of a logic model provided a visual representation of the Kids Together model and its component parts and enabled a theory of change to be inferred, showing how a coordinated and collaborative approached can work across multiple environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Effect of Various Food Additives on the Levels of 4(5)-Methylimidazole in a Soy Sauce Model System.

    Science.gov (United States)

    Lee, Sumin; Lee, Jung-Bin; Hwang, Junho; Lee, Kwang-Geun

    2016-01-01

    In this study, the effect of food additives such as iron sulfate, magnesium sulfate, zinc sulfate, citric acid, gallic acid, and ascorbic acid on the reduction of 4(5)-methylimidazole (4(5)-MI) was investigated using a soy sauce model system. The concentration of 4(5)-MI in the soy sauce model system with 5% (v/v) caramel colorant III was 1404.13 μg/L. The reduction rate of 4(5)-MI level with the addition of 0.1M additives followed in order: iron sulfate (81%) > zinc sulfate (61%) > citric acid (40%) > gallic acid (38%) > ascorbic acid (24%) > magnesium sulfate (13%). Correlations between 4(5)-MI levels and the physicochemical properties of soy sauce, including the amount of caramel colorant, pH value, and color differences, were determined. The highest correlations were found between 4(5)-MI levels and the amount of caramel colorant and pH values (r(2) = 0.9712, r(2) = 0.9378). The concentration of caramel colorants in 8 commercial soy sauces were estimated, and ranged from 0.01 to 1.34% (v/v). © 2015 Institute of Food Technologists®

  16. [Assessment of the effect of selected mixture of food additives on the protein metabolism--model studies].

    Science.gov (United States)

    Friedrich, Mariola; Kuchlewska, Magdalena

    2012-01-01

    Contemporarily, food production without food additives is very rare. Increasingly often, however, scientific works report on adverse effects of specified, single food additives on the body. Data is, in turn, lacking on the synergistic effect of a mixture of different food additives on body functions and its main metabolic pathways. The objective of this study, an animal model, was to evaluate if and in what way the compound of chosen and most frequently used and consumed food additives, along with the change of diet composition to processed, purified, influence the selected markers of protein metabolism. The animals were divided into four groups, which were fed with compound of feed pellets: group I and II with basic compound, group III and IV with modified compound in which part of the full grain was replaced by isocalorie wheat flour type 500 and saccharose. Animals from groups I and III received tap water, which was standing for some time, to drink. Animals from groups II and IV received solution of chosen additives to food and next they were given water to drink. The amount of given food additives was evaluated by taking into consideration their consumption by people recalculated to 1 kg of their body mass. The experiment spanned for 7 weeks. It was ascertained that the applied additives caused significant changes in total protein concentration and its fractions: albumin, alpha1-globulin, alpha2-globulin, beta-globulin and gamma-globulin in the blood serum of the animals under research, which can indicate and contribute to disclosure of creation of undesirable food reaction, especially when recommended levels of consumption of those additives are being exceeded. The organism response to the applied additives and accompanying it change of diet was essentially connected to sex of the animals. Undesirable character of changes taking place under the influence of applied additives, was observed both in animals fed with basic feed and modified feed with various

  17. The bystander effect model of Brenner and Sachs fitted to lung cancer data in 11 cohorts of underground miners, and equivalence of fit of a linear relative risk model with adjustment for attained age and age at exposure

    International Nuclear Information System (INIS)

    Little, M P

    2004-01-01

    Bystander effects following exposure to α-particles have been observed in many experimental systems, and imply that linearly extrapolating low dose risks from high dose data might materially underestimate risk. Brenner and Sachs (2002 Int. J. Radiat. Biol. 78 593-604; 2003 Health Phys. 85 103-8) have recently proposed a model of the bystander effect which they use to explain the inverse dose rate effect observed for lung cancer in underground miners exposed to radon daughters. In this paper we fit the model of the bystander effect proposed by Brenner and Sachs to 11 cohorts of underground miners, taking account of the covariance structure of the data and the period of latency between the development of the first pre-malignant cell and clinically overt cancer. We also fitted a simple linear relative risk model, with adjustment for age at exposure and attained age. The methods that we use for fitting both models are different from those used by Brenner and Sachs, in particular taking account of the covariance structure, which they did not, and omitting certain unjustifiable adjustments to the miner data. The fit of the original model of Brenner and Sachs (with 0 y period of latency) is generally poor, although it is much improved by assuming a 5 or 6 y period of latency from the first appearance of a pre-malignant cell to cancer. The fit of this latter model is equivalent to that of a linear relative risk model with adjustment for age at exposure and attained age. In particular, both models are capable of describing the observed inverse dose rate effect in this data set

  18. Real-time interferometric monitoring and measuring of photopolymerization based stereolithographic additive manufacturing process: sensor model and algorithm

    Science.gov (United States)

    Zhao, X.; Rosen, D. W.

    2017-01-01

    As additive manufacturing is poised for growth and innovations, it faces barriers of lack of in-process metrology and control to advance into wider industry applications. The exposure controlled projection lithography (ECPL) is a layerless mask-projection stereolithographic additive manufacturing process, in which parts are fabricated from photopolymers on a stationary transparent substrate. To improve the process accuracy with closed-loop control for ECPL, this paper develops an interferometric curing monitoring and measuring (ICM&M) method which addresses the sensor modeling and algorithms issues. A physical sensor model for ICM&M is derived based on interference optics utilizing the concept of instantaneous frequency. The associated calibration procedure is outlined for ICM&M measurement accuracy. To solve the sensor model, particularly in real time, an online evolutionary parameter estimation algorithm is developed adopting moving horizon exponentially weighted Fourier curve fitting and numerical integration. As a preliminary validation, simulated real-time measurement by offline analysis of a video of interferograms acquired in the ECPL process is presented. The agreement between the cured height estimated by ICM&M and that measured by microscope indicates that the measurement principle is promising as real-time metrology for global measurement and control of the ECPL process.

  19. Utilization of Titanium Particle Impact Location to Validate a 3D Multicomponent Model for Cold Spray Additive Manufacturing

    Science.gov (United States)

    Faizan-Ur-Rab, M.; Zahiri, S. H.; King, P. C.; Busch, C.; Masood, S. H.; Jahedi, M.; Nagarajah, R.; Gulizia, S.

    2017-12-01

    Cold spray is a solid-state rapid deposition technology in which metal powder is accelerated to supersonic speeds within a de Laval nozzle and then impacts onto the surface of a substrate. It is possible for cold spray to build thick structures, thus providing an opportunity for melt-less additive manufacturing. Image analysis of particle impact location and focused ion beam dissection of individual particles were utilized to validate a 3D multicomponent model of cold spray. Impact locations obtained using the 3D model were found to be in close agreement with the empirical data. Moreover, the 3D model revealed the particles' velocity and temperature just before impact—parameters which are paramount for developing a full understanding of the deposition process. Further, it was found that the temperature and velocity variations in large-size particles before impact were far less than for the small-size particles. Therefore, an optimal particle temperature and velocity were identified, which gave the highest deformation after impact. The trajectory of the particles from the injection point to the moment of deposition in relation to propellant gas is visualized. This detailed information is expected to assist with the optimization of the deposition process, contributing to improved mechanical properties for additively manufactured cold spray titanium parts.

  20. Modeling the Impact of School-Based Universal Depression Screening on Additional Service Capacity Needs: A System Dynamics Approach.

    Science.gov (United States)

    Lyon, Aaron R; Maras, Melissa A; Pate, Christina M; Igusa, Takeru; Vander Stoep, Ann

    2016-03-01

    Although it is widely known that the occurrence of depression increases over the course of adolescence, symptoms of mood disorders frequently go undetected. While schools are viable settings for conducting universal screening to systematically identify students in need of services for common health conditions, particularly those that adversely affect school performance, few school districts routinely screen their students for depression. Among the most commonly referenced barriers are concerns that the number of students identified may exceed schools' service delivery capacities, but few studies have evaluated this concern systematically. System dynamics (SD) modeling may prove a useful approach for answering questions of this sort. The goal of the current paper is therefore to demonstrate how SD modeling can be applied to inform implementation decisions in communities. In our demonstration, we used SD modeling to estimate the additional service demand generated by universal depression screening in a typical high school. We then simulated the effects of implementing "compensatory approaches" designed to address anticipated increases in service need through (1) the allocation of additional staff time and (2) improvements in the effectiveness of mental health interventions. Results support the ability of screening to facilitate more rapid entry into services and suggest that improving the effectiveness of mental health services for students with depression via the implementation of an evidence-based treatment protocol may have a limited impact on overall recovery rates and service availability. In our example, the SD approach proved useful in informing systems' decision-making about the adoption of a new school mental health service.

  1. Real-time interferometric monitoring and measuring of photopolymerization based stereolithographic additive manufacturing process: sensor model and algorithm

    International Nuclear Information System (INIS)

    Zhao, X; Rosen, D W

    2017-01-01

    As additive manufacturing is poised for growth and innovations, it faces barriers of lack of in-process metrology and control to advance into wider industry applications. The exposure controlled projection lithography (ECPL) is a layerless mask-projection stereolithographic additive manufacturing process, in which parts are fabricated from photopolymers on a stationary transparent substrate. To improve the process accuracy with closed-loop control for ECPL, this paper develops an interferometric curing monitoring and measuring (ICM and M) method which addresses the sensor modeling and algorithms issues. A physical sensor model for ICM and M is derived based on interference optics utilizing the concept of instantaneous frequency. The associated calibration procedure is outlined for ICM and M measurement accuracy. To solve the sensor model, particularly in real time, an online evolutionary parameter estimation algorithm is developed adopting moving horizon exponentially weighted Fourier curve fitting and numerical integration. As a preliminary validation, simulated real-time measurement by offline analysis of a video of interferograms acquired in the ECPL process is presented. The agreement between the cured height estimated by ICM and M and that measured by microscope indicates that the measurement principle is promising as real-time metrology for global measurement and control of the ECPL process. (paper)

  2. Modelling the average velocity of propagation of the flame front in a gasoline engine with hydrogen additives

    Science.gov (United States)

    Smolenskaya, N. M.; Smolenskii, V. V.

    2018-01-01

    The paper presents models for calculating the average velocity of propagation of the flame front, obtained from the results of experimental studies. Experimental studies were carried out on a single-cylinder gasoline engine UIT-85 with hydrogen additives up to 6% of the mass of fuel. The article shows the influence of hydrogen addition on the average velocity propagation of the flame front in the main combustion phase. The dependences of the turbulent propagation velocity of the flame front in the second combustion phase on the composition of the mixture and operating modes. The article shows the influence of the normal combustion rate on the average flame propagation velocity in the third combustion phase.

  3. Using satellite-derived backscattering coefficients in addition to chlorophyll data to constrain a simple marine biogeochemical model

    Directory of Open Access Journals (Sweden)

    H. Kettle

    2009-08-01

    Full Text Available Biogeochemical models of the ocean carbon cycle are frequently validated by, or tuned to, satellite chlorophyll data. However, ocean carbon cycle models are required to accurately model the movement of carbon, not chlorophyll, and due to the high variability of the carbon to chlorophyll ratio in phytoplankton, chlorophyll is not a robust proxy for carbon. Using inherent optical property (IOP inversion algorithms it is now possible to also derive the amount of light backscattered by the upper ocean (bb which is related to the amount of particulate organic carbon (POC present. Using empirical relationships between POC and bb, a 1-D marine biogeochemical model is used to simulate bb at 490 nm thereby allowing the model to be compared with both remotely-sensed chlorophyll or bb data. Here I investigate the possibility of using bb in conjunction with chlorophyll data to help constrain the parameters in a simple 1-D NPZD model. The parameters of the biogeochemical model are tuned with a genetic algorithm, so that the model is fitted to either chlorophyll data or to both chlorophyll and bb data at three sites in the Atlantic with very different characteristics. Several inherent optical property (IOP algorithms are available for estimating bb, three of which are used here. The effect of the different bb datasets on the behaviour of the tuned model is examined to ascertain whether the uncertainty in bb is significant. The results show that the addition of bb data does not consistently alter the same model parameters at each site and in fact can lead to some parameters becoming less well constrained, implying there is still much work to be done on the mechanisms relating chlorophyll to POC and bb within the model. However, this study does indicate that

  4. Altimetry, gravimetry, GPS and viscoelastic modeling data for the joint inversion for glacial isostatic adjustment in Antarctica (ESA STSE Project REGINA)

    Science.gov (United States)

    Sasgen, Ingo; Martín-Español, Alba; Horvath, Alexander; Klemann, Volker; Petrie, Elizabeth J.; Wouters, Bert; Horwath, Martin; Pail, Roland; Bamber, Jonathan L.; Clarke, Peter J.; Konrad, Hannes; Wilson, Terry; Drinkwater, Mark R.

    2018-03-01

    The poorly known correction for the ongoing deformation of the solid Earth caused by glacial isostatic adjustment (GIA) is a major uncertainty in determining the mass balance of the Antarctic ice sheet from measurements of satellite gravimetry and to a lesser extent satellite altimetry. In the past decade, much progress has been made in consistently modeling ice sheet and solid Earth interactions; however, forward-modeling solutions of GIA in Antarctica remain uncertain due to the sparsity of constraints on the ice sheet evolution, as well as the Earth's rheological properties. An alternative approach towards estimating GIA is the joint inversion of multiple satellite data - namely, satellite gravimetry, satellite altimetry and GPS, which reflect, with different sensitivities, trends in recent glacial changes and GIA. Crucial to the success of this approach is the accuracy of the space-geodetic data sets. Here, we present reprocessed rates of surface-ice elevation change (Envisat/Ice, Cloud,and land Elevation Satellite, ICESat; 2003-2009), gravity field change (Gravity Recovery and Climate Experiment, GRACE; 2003-2009) and bedrock uplift (GPS; 1995-2013). The data analysis is complemented by the forward modeling of viscoelastic response functions to disc load forcing, allowing us to relate GIA-induced surface displacements with gravity changes for different rheological parameters of the solid Earth. The data and modeling results presented here are available in the PANGAEA database (https://doi.org/10.1594/PANGAEA.875745" target="_blank">https://doi.org/10.1594/PANGAEA.875745). The data sets are the input streams for the joint inversion estimate of present-day ice-mass change and GIA, focusing on Antarctica. However, the methods, code and data provided in this paper can be used to solve other problems, such as volume balances of the Antarctic ice sheet, or can be applied to other geographical regions in the case of the viscoelastic response functions. This paper

  5. Fatigue Behavior and Modeling of Additively Manufactured Ti-6Al-4V Including Interlayer Time Interval Effects

    Science.gov (United States)

    Torries, Brian; Shamsaei, Nima

    2017-12-01

    The effects of different cooling rates, as achieved by varying the interlayer time interval, on the fatigue behavior of additively manufactured Ti-6Al-4V specimens were investigated and modeled via a microstructure-sensitive fatigue model. Comparisons are made between two sets of specimens fabricated via Laser Engineered Net Shaping (LENS™), with variance in interlayer time interval accomplished by depositing either one or two specimens per print operation. Fully reversed, strain-controlled fatigue tests were conducted, with fractography following specimen failure. A microstructure-sensitive fatigue model was calibrated to model the fatigue behavior of both sets of specimens and was found to be capable of correctly predicting the longer fatigue lives of the single-built specimens and the reduced scatter of the double-built specimens; all data points fell within the predicted upper and lower bounds of fatigue life. The time interval effects and the ability to be modeled are important to consider when producing test specimens that are smaller than the production part (i.e., property-performance relationships).

  6. The role of additive neurogenesis and synaptic plasticity in a hippocampal memory model with grid-cell like input.

    Directory of Open Access Journals (Sweden)

    Peter A Appleby

    Full Text Available Recently, we presented a study of adult neurogenesis in a simplified hippocampal memory model. The network was required to encode and decode memory patterns despite changing input statistics. We showed that additive neurogenesis was a more effective adaptation strategy compared to neuronal turnover and conventional synaptic plasticity as it allowed the network to respond to changes in the input statistics while preserving representations of earlier environments. Here we extend our model to include realistic, spatially driven input firing patterns in the form of grid cells in the entorhinal cortex. We compare network performance across a sequence of spatial environments using three distinct adaptation strategies: conventional synaptic plasticity, where the network is of fixed size but the connectivity is plastic; neuronal turnover, where the network is of fixed size but units in the network may die and be replaced; and additive neurogenesis, where the network starts out with fewer initial units but grows over time. We confirm that additive neurogenesis is a superior adaptation strategy when using realistic, spatially structured input patterns. We then show that a more biologically plausible neurogenesis rule that incorporates cell death and enhanced plasticity of new granule cells has an overall performance significantly better than any one of the three individual strategies operating alone. This adaptation rule can be tailored to maximise performance of the network when operating as either a short- or long-term memory store. We also examine the time course of adult neurogenesis over the lifetime of an animal raised under different hypothetical rearing conditions. These growth profiles have several distinct features that form a theoretical prediction that could be tested experimentally. Finally, we show that place cells can emerge and refine in a realistic manner in our model as a direct result of the sparsification performed by the dentate gyrus

  7. Leg-adjustment strategies for stable running in three dimensions

    International Nuclear Information System (INIS)

    Peuker, Frank; Maufroy, Christophe; Seyfarth, André

    2012-01-01

    The dynamics of the center of mass (CoM) in the sagittal plane in humans and animals during running is well described by the spring-loaded inverted pendulum (SLIP). With appropriate parameters, SLIP running patterns are stable, and these models can recover from perturbations without the need for corrective strategies, such as the application of additional forces. Rather, it is sufficient to adjust the leg to a fixed angle relative to the ground. In this work, we consider the extension of the SLIP to three dimensions (3D SLIP) and investigate feed-forward strategies for leg adjustment during the flight phase. As in the SLIP model, the leg is placed at a fixed angle. We extend the scope of possible reference axes from only fixed horizontal and vertical axes to include the CoM velocity vector as a movement-related reference, resulting in six leg-adjustment strategies. Only leg-adjustment strategies that include the CoM velocity vector produced stable running and large parameter domains of stability. The ability of the model to recover from perturbations along the direction of motion (directional stability) depended on the strategy for lateral leg adjustment. Specifically, asymptotic and neutral directional stability was observed for strategies based on the global reference axis and the velocity vector, respectively. Additional features of velocity-based leg adjustment are running at arbitrary low speed (kinetic energy) and the emergence of large domains of stable 3D running that are smoothly transferred to 2D SLIP stability and even to 1D SLIP hopping. One of the additional leg-adjustment strategies represented a large convex region of parameters where stable and robust hopping and running patterns exist. Therefore, this strategy is a promising candidate for implementation into engineering applications, such as robots, for instance. In a preliminary comparison, the model predictions were in good agreement with the experimental data, suggesting that the 3D SLIP is an

  8. Applied mixed generalized additive model to assess the effect of temperature on the incidence of bacillary dysentery and its forecast.

    Directory of Open Access Journals (Sweden)

    Weiping Ma

    Full Text Available BACKGROUND: Association between bacillary dysentery (BD disease and temperature has been reported in some studies applying Poisson regression model, however the effect estimation might be biased due to the data autocorrelation. Furthermore the temperature effect distributed in the time of different lags has not been studied either. The purpose of this work was to obtaining the association between the BD counts and the climatic factors such as temperature in the form of the weighted averages, concerning the autocorrelation pattern of the model residuals, and to make short term predictions using the model. The data was collected in the city of Shanghai from 2004 to 2008. METHODS: We used mixed generalized additive model (MGAM to analyze data on bacillary dysentery, temperature and other covariates with autoregressive random effect. Short term predictions were made using MGAM with the moving average of the BD counts. MAIN RESULTS: Our results showed that temperature was significant linearly associated with the logarithm of BD count for temperature in the range from 12°C to 22°C. Optimal weights in the temperature effect have been obtained, in which the one of 1-day-lag was close to 0, and the one of 2-days-lag was the maximum (p-value of the difference was less than 0.05. The predictive model was showing good fitness on the internal data with R(2 value 0.875, and the good short term prediction effect on the external data with correlation coefficient to be 0.859. CONCLUSION: According to the model estimation, corresponding Risk Ratio to affect BD was close to 1.1 when temperature effect goes up for 1°C in the range from 12°C to 22°C. And the 1-day incubation period could be inferred from the model estimation. Good prediction has been made using the predictive MGAM.

  9. 42 CFR 422.310 - Risk adjustment data.

    Science.gov (United States)

    2010-10-01

    ....310 Risk adjustment data. (a) Definition of risk adjustment data. Risk adjustment data are all data that are used in the development and application of a risk adjustment payment model. (b) Data... 42 Public Health 3 2010-10-01 2010-10-01 false Risk adjustment data. 422.310 Section 422.310...

  10. Data-driven multi-scale multi-physics models to derive process-structure-property relationships for additive manufacturing

    Science.gov (United States)

    Yan, Wentao; Lin, Stephen; Kafka, Orion L.; Lian, Yanping; Yu, Cheng; Liu, Zeliang; Yan, Jinhui; Wolff, Sarah; Wu, Hao; Ndip-Agbor, Ebot; Mozaffar, Mojtaba; Ehmann, Kornel; Cao, Jian; Wagner, Gregory J.; Liu, Wing Kam

    2018-01-01

    Additive manufacturing (AM) possesses appealing potential for manipulating material compositions, structures and properties in end-use products with arbitrary shapes without the need for specialized tooling. Since the physical process is difficult to experimentally measure, numerical modeling is a powerful tool to understand the underlying physical mechanisms. This paper presents our latest work in this regard based on comprehensive material modeling of process-structure-property relationships for AM materials. The numerous influencing factors that emerge from the AM process motivate the need for novel rapid design and optimization approaches. For this, we propose data-mining as an effective solution. Such methods—used in the process-structure, structure-properties and the design phase that connects them—would allow for a design loop for AM processing and materials. We hope this article will provide a road map to enable AM fundamental understanding for the monitoring and advanced diagnostics of AM processing.

  11. A bootstrap method to avoid the effect of concurvity in generalised additive models in time series studies of air pollution.

    Science.gov (United States)

    Figueiras, Adolfo; Roca-Pardiñas, Javier; Cadarso-Suárez, Carmen

    2005-10-01

    In recent years a great number of studies have applied generalised additive models (GAMs) to time series data to estimate the short term health effects of air pollution. Lately, however, it has been found that concurvity--the non-parametric analogue of multicollinearity--might lead to underestimation of standard errors of the effects of independent variables. Underestimation of standard errors means that for concurvity levels commonly present in the data, the risk of committing type I error rises by over threefold. This study developed a conditional bootstrap methology that consists of assuming that the outcome in any observation is conditional upon the values of the set of independent variables used. It then tested this procedure by means of a simulation study using a Poisson additive model. The response variable of this model is a function of an unobserved confounding variable (that introduces trend and seasonality), real black smoke data, and temperature. Scenarios were created with different coefficients and degrees of concurvity. Conditional bootstrap provides confidence intervals with coverages close to nominal (95%), irrespective of the degree of concurvity, number of variables in the model or magnitude of the coefficient to be estimated (for example, for a concurvity of 0.85, bootstrap confidence interval coverage is 95% compared with 71% in the case of the asymptotic interval obtained directly with S-plus gam function). The bootstrap method avoids the problem of concurvity in time series studies of air pollution, and is easily generalised to non-linear dose-risk effects. All bootstrap calculations described in this paper can be performed using S-Plus gam.boot software.

  12. Lithosphere and upper-mantle structure of the southern Baltic Sea estimated from modelling relative sea-level data with glacial isostatic adjustment

    Science.gov (United States)

    Steffen, H.; Kaufmann, G.; Lampe, R.

    2014-06-01

    thickness as determined with ICE-5G does not agree with the lithosphere models. Hence, more investigations have to be undertaken to sufficiently determine structures such as the Ringkøbing-Fyn High as seen with seismics with the help of glacial isostatic adjustment modelling.

  13. Influence of tribomechanical micronization and hydrocolloids addition on enthalpy and apparent specific heat of whey protein model solutions

    Directory of Open Access Journals (Sweden)

    Zoran Herceg

    2002-01-01

    Full Text Available Knowledge of thermophysical properties, especially the phase transitions temperature, specific heat and enthalpy, are essential in defining the freezing process parameters as well as storage conditions of frozen food. In this work thermophysical properties of 10% model solutions prepared with 60% whey protein concentrate (WPC with various hydrocolloids addition (HVEP, YO-EH, YO-L i YO-M were investigated. Powdered whey protein concentrate was treated in equipment for tribomechanical micronization and activation at 40000 rpm (Patent: PCT/1B99/00757 just before model solutions preparation. Particle size analysis was performed using Frich –laser particle sizer “analysette 22”. The phase transition temperatures were determined by differential thermal analysis (DTA, while specific heat and enthalpy were calculated according to several mathematical equations. The results have shown that, due to tribomechanical treatment, certain changes in thermophysical and energetic properties of materials occurred. Tribomechanical treatment affects changes in granulometrical composition of WPC which result in higher abilities of reactions with hydrocolloids in model solutions and significant changes in thermophysical properties of the mentioned models.

  14. Adjustable Model of Renewable Energy Projects for Sustainable Development: A Case Study of the Nišava District in Serbia

    Directory of Open Access Journals (Sweden)

    Violeta Dimić

    2018-03-01

    Full Text Available This paper explores and ranks the key performance indicators of multi-criteria decision-making in the process of selecting renewable energy sources (RES. Different categories of factors (e.g., political, legal, technological, economic and financial, sociocultural, and physical are crucial for the analysis of such projects. In this paper, we apply the fuzzy analytic hierarchy process (fuzzy AHP method—a mathematical method—in order to analyze the main criteria for such projects, which include the environment, the organizational management structure, project participants, and participants’ relationship with the performance indicators. In order of ranking, the indicators are the following: time, costs, quality, monitoring the project’s sustainability, user feedback, and users’ health and safety. The aim of this paper is to point out the necessity of creating an adjustable model for renewable energy projects in order to proceed with the sustainable development of the southeast part of Serbia. This model should lead the creation process for such a project, with the aim of increasing its energy efficiency.

  15. Scenario analysis of carbon emissions' anti-driving effect on Qingdao's energy structure adjustment with an optimization model, Part II: Energy system planning and management.

    Science.gov (United States)

    Wu, C B; Huang, G H; Liu, Z P; Zhen, J L; Yin, J G

    2017-03-01

    In this study, an inexact multistage stochastic mixed-integer programming (IMSMP) method was developed for supporting regional-scale energy system planning (EPS) associated with multiple uncertainties presented as discrete intervals, probability distributions and their combinations. An IMSMP-based energy system planning (IMSMP-ESP) model was formulated for Qingdao to demonstrate its applicability. Solutions which can provide optimal patterns of energy resources generation, conversion, transmission, allocation and facility capacity expansion schemes have been obtained. The results can help local decision makers generate cost-effective energy system management schemes and gain a comprehensive tradeoff between economic objectives and environmental requirements. Moreover, taking the CO 2 emissions scenarios mentioned in Part I into consideration, the anti-driving effect of carbon emissions on energy structure adjustment was studied based on the developed model and scenario analysis. Several suggestions can be concluded from the results: (a) to ensure the smooth realization of low-carbon and sustainable development, appropriate price control and fiscal subsidy on high-cost energy resources should be considered by the decision-makers; (b) compared with coal, natural gas utilization should be strongly encouraged in order to insure that Qingdao could reach the carbon discharges peak value in 2020; (c) to guarantee Qingdao's power supply security in the future, the construction of new power plants should be emphasised instead of enhancing the transmission capacity of grid infrastructure. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Dynamic gauge adjustment of high-resolution X-band radar data for convective rain storms: Model-based evaluation against measured combined sewer overflow

    DEFF Research Database (Denmark)

    Borup, Morten; Grum, Morten; Linde, Jens Jørgen

    2016-01-01

    overflows from urban drainage systems, and we furthermore investigate the importance of the aggregation period of the adjustment scheme. This is done by continuously adjusting X-band radar data based on the previous 5–30 min of rain data recorded by multiple rain gauges and propagating the rainfall......, well defined, 64 ha urban catchment, for nine overflow generating rain events. The dynamically adjusted radar data perform best when the aggregation period is as small as 10–20 min, in which case it performs much better than static adjusted radar data and data from rain gauges situated 2–3 km away....

  17. Stability improvement of natural food colors: Impact of amino acid and peptide addition on anthocyanin stability in model beverages.

    Science.gov (United States)

    Chung, Cheryl; Rojanasasithara, Thananunt; Mutilangi, William; McClements, David Julian

    2017-03-01

    Anthocyanins are prone to chemical degradation and color fading in the presence of vitamin C. The potential of three amino acids (l-phenylalanine, l-tyrosine, l-tryptophan) and a polypeptide (ε-poly-l-lysine) in prolonging the color stability of purple carrot anthocyanins (0.025%) in model beverages (0.05% l-ascorbic acid, citric acid, pH 3.0) stored at elevated temperature (40°C/7 days) was examined. In the absence of amino acids or peptides, anthocyanin degraded at first-order reaction rate. Addition of amino acids or peptide (0.1%) increased the color stability of anthocyanins, with the most significant improvement observed for l-tryptophan. The average half-life of anthocyanin color increased from 2 days to 6 days with l-tryptophan addition. Fluorescence quenching measurements revealed that the l-tryptophan interacted with anthocyanins mainly through hydrogen bonding, although some hydrophobic interaction may also have been involved. Overall, this study suggests that amino acid or peptide addition may prolong the color stability of anthocyanin in beverage products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Testing the additive versus the compensatory hypothesis of mortality from ring recovery data using a random effects model

    Directory of Open Access Journals (Sweden)

    Schaub, M.

    2004-06-01

    Full Text Available The interaction of an additional source of mortality with the underlying “natural” one strongly affects population dynamics. We propose an alternative way to test between two forms of interaction, total additivity and compensation. In contrast to existing approaches, only ring-recovery data where the cause of death of each recovered individual is known are needed. Cause-specific mortality proportions are estimated based on a multistate capture-recapture model. The hypotheses are tested by inspecting the correlation between the cause-specific mortality proportions. A variance decomposition is performed to obtain a proper estimate of the true process correlation. The estimation of the cause-specific mortality proportions is the most critical part of the approach. It works well if at least one of the two mortality rates varies across time and the two recovery rates are constant across time. We illustrate this methodology by a case study of White Storks Ciconia ciconia where we tested whether mortality induced by power line collision is additive to other forms of mortality.

  19. Microbial modeling of thermal resistance of Alicyclobacillus acidoterrestris CRA7152 spores in concentrated orange juice with nisin addition

    Science.gov (United States)

    Peña, Wilmer Edgard Luera; de Massaguer, Pilar Rodriguez; Teixeira, Luciano Quintão

    2009-01-01

    The nisin effect on thermal death of Alicyclobacillus acidoterrestris CRA 7152 spores in concentrated orange juice (64°Brix) was studied. Concentrations of 0, 50, 75 and 100 IU of nisin/ml juice, at temperatures of 92, 95, 98 and 102°C were evaluated. The quadratic polynomial model was used to analyze the effects of the factors and their interaction. Verification of surviving spores was carried out through plating in K medium (pH 3.7). The results showed that the D values without nisin addition were 25.5, 12.9, 6.1 and 2.3 min for 92, 95, 98 and 102°C respectively. With addition of nisin into the juice there was a drop of heat resistance as the concentration was increased at a same temperature. With 30, 50, 75, 100 and 150 IU/ml at 95°C, the D values were 12.34, 11.38, 10.49, 9.49 and 9.42 min respectively, showing that a decrease in the D value up to 27% can be obtained. The second order polynomial model established with r2 = 0.995 showed that the microorganism resistance was affected by the action of temperature followed by the nisin concentration. Nisin therefore is an alternative for reducing the rigor of the A. acidoterrestris CRA 7152 thermal treatment. PMID:24031405

  20. Biocontrol of Listeria monocytogenes in a meat model using a combination of a bacteriocinogenic strain with curing additives.

    Science.gov (United States)

    Orihuel, Alejandra; Bonacina, Julieta; Vildoza, María José; Bru, Elena; Vignolo, Graciela; Saavedra, Lucila; Fadda, Silvina

    2018-05-01

    The aim of this work was to evaluate the effect of meat curing agents on the bioprotective activity of the bacteriocinogenic strain, Enterococcus (E.) mundtii CRL35 against Listeria (L.) monocytogenes during meat fermentation. The ability of E. mundtii CRL35 to grow, acidify and produce bacteriocin in situ was assayed in a meat model system in the presence of curing additives (CA). E. mundtii CRL35 showed optimal growth and acidification rates in the presence of CA. More importantly, the highest bacteriocin titer was achieved in the presence of these food agents. In addition, the CA produced a statistical significant enhancement of the enterocin CRL35 activity. This positive effect was demonstrated in vitro in a meat based culture medium, by time-kill kinetics and finally by using a beaker sausage model with a challenge experiment with the pathogenic L. monocytogenes FBUNT strain. E. mundtii CRL35 was found to be a promising strain of use as a safety adjunct culture in meat industry and a novel functional supplement for sausage fermentation, ensuring hygiene and quality of the final product. Copyright © 2018 Elsevier Ltd. All rights reserved.