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1

Structural analysis equations  

Treesearch

General technical report FPL ; GTR-190. ... Description: Equations for deformation and stress, which are the basis for tension ... Keywords: Structural analysis, elasticity, bending, mathematical models, equations, mechanical properties, ...

2

Structural Equation Model Trees  

ERIC Educational Resources Information Center

|In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

2013-01-01

3

Bayesian Structural Equation Modeling  

Microsoft Academic Search

Structural equation models (SEMs) with latent variables are routinely used in social science research, and are of increasing importance in biomedical applications. Standard practice in implementing SEMs relies on frequentist methods. This chapter provides a simple and concise description of an alternative Bayesian approach. We provide a brief overview of the literature, describe a Bayesian speciflcation of SEMs, and outline

David B. Dunson; Jesus Palomo; Ken Bollen

4

Generalized multilevel structural equation modeling  

Microsoft Academic Search

A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent variables. The response model generalizes GLMMs to incorporate factor structures

Sophia Rabe-Hesketh; Anders Skrondal; Andrew Pickles

2004-01-01

5

Generalized Multilevel Structural Equation Modeling  

ERIC Educational Resources Information Center

A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent…

Rabe-Hesketh, Sophia; Skrondal, Anders; Pickles, Andrew

2004-01-01

6

Structural Equation Modeling: Categorical Variables  

Microsoft Academic Search

In the behavioral sciences, response variables are often noncontinuous, common types be- ing dichotomous, ordinal or nominal variables, counts and durations. Conventional structural equation models (SEMs) have thus been generalized to accommodate different kinds of re- sponses.

Anders Skrondal; Sophia Rabe-Hesketh

7

Selective Mutism Questionnaire: Measurement Structure and Validity  

ERIC Educational Resources Information Center

The psychometric properties of the Selective Mutism Questionnaire (SMQ) are evaluated using a clinical sample of children with selective mutism (SM). The study shows that SMQ is useful in determining the severity of a child's nonspeaking behaviors, the scope of these behaviors and necessary follow up assessment.

Letamendi, Andrea M.; Chavira, Denise A.; Hitchcock, Carla A.; Roesch, Scott C.; Shipon-Blum, Elisa; Stein, Murray B.

2008-01-01

8

The Bilevel Structure of the Outcome Questionnaire-45  

ERIC Educational Resources Information Center

The structure of the Outcome Questionnaire-45 (Lambert et al., 2001) was examined in a sample of 1,100 university counseling center clients using confirmatory factor analysis. Specifically, the relative fit of 1-factor, 3-factor orthogonal, 3-factor oblique, 4-factor hierarchical, and 4-factor bilevel models were examined. Although the 3-factor…

Bludworth, Jamie L.; Tracey, Terence J. G.; Glidden-Tracey, Cynthia

2010-01-01

9

Revisiting the Factor Structure of the Questionnaire on Smoking Urges  

ERIC Educational Resources Information Center

|This study assessed the factor structure of the Questionnaire on Smoking Urges (QSU), a commonly used assessment of cravings for cigarettes, with a sample of smokers presenting for treatment in a smoking cessation trial. On the basis of previous research, three confirmatory factor analytic models were tested. Model 1 hypothesized a 26-item,…

Toll, Benjamin A.; McKee, Sherry A.; Krishnan-Sarin, Suchitra; O'Malley, Stephanie S.

2004-01-01

10

The Structure and Validity of the Multidimensional Social Support Questionnaire  

ERIC Educational Resources Information Center

|The factor structure and concurrent validity of the Multidimensional Social Support Questionnaire, a brief measure of perceived social support for use with adolescents, was examined. Findings suggest that four dimensions of perceived social support may yield more information than assessments of the unitary construct of support. (Contains 8 tables…

Hardesty, Patrick H.; Richardson, George B.

2012-01-01

11

Revisiting the Factor Structure of the Questionnaire on Smoking Urges  

Microsoft Academic Search

This study assessed the factor structure of the Questionnaire on Smoking Urges (QSU), a commonly used assessment of cravings for cigarettes, with a sample of smokers presenting for treatment in a smoking cessation trial. On the basis of previous research, three confirmatory factor analytic models were tested. Model 1 hypothesized a 26-item, 2-factor model using the items reported in the

Benjamin A. Toll; Sherry A. McKee; Suchitra Krishnan-Sarin; Stephanie S. OMalley

2004-01-01

12

Revisiting the Factor Structure of the Questionnaire on Smoking Urges  

ERIC Educational Resources Information Center

This study assessed the factor structure of the Questionnaire on Smoking Urges (QSU), a commonly used assessment of cravings for cigarettes, with a sample of smokers presenting for treatment in a smoking cessation trial. On the basis of previous research, three confirmatory factor analytic models were tested. Model 1 hypothesized a 26-item,…

Toll, Benjamin A.; McKee, Sherry A.; Krishnan-Sarin, Suchitra; O'Malley, Stephanie S.

2004-01-01

13

Patient Health Questionnaire: Greek language validation and subscale factor structure.  

PubMed

This study aimed to assess the reliability, validity, and factor structure of the Greek translation of the Patient Health Questionnaire (PHQ) in a sample of Cypriot, Greek-speaking university students. This is the first study to examine PHQ psychometric properties in Greek and to investigate the factor structure of the PHQ subscales. A total of 520 participants (73.9% women; M(Age) = 21.57; SD, 4.94) completed the PHQ and assessment tools used for convergent validity analysis. Patient Health Questionnaire was translated and culturally adapted according to international standards. Overall, PHQ subscales in Greek language demonstrated good internal consistency (mean Cronbach ? = .75, P < .001) and convergent validity with the following: Alcohol Use Disorders Identification Test, Beck Depression Inventory, Psychiatric Diagnostic Screening Questionnaire (panic disorder, somatization, bulimia, and binge eating), and Anxiety Sensitivity Index (overall mean, r = 0.52; P < .001). The relation between the PHQ subscale diagnoses and functional impairment, as assessed by the 12-item Health Survey 12, was comparable with the original validation results for all subscales except alcohol. The depression, alcohol, and anxiety subscales exhibited single-factor structures. Subscales assessing eating disorders, panic disorder, and somatization difficulties exhibited 2-, 3-, and 4-factor structures, respectively. Overall, PHQ subscales demonstrated good psychometric properties, with the exception of the subscale examining problematic alcohol use. Overall, PHQ demonstrates good reliability, validity, and appropriate factor structure in a Greek-speaking college population. Psychometric research is needed on the Greek PHQ in primary care settings. PMID:22901833

Karekla, Maria; Pilipenko, Nataliya; Feldman, Jonathan

2012-08-15

14

The Infant Crying Questionnaire: initial factor structure and validation.  

PubMed

The current project reports on an initial investigation into the factor structure of the Infant Crying Questionnaire (ICQ), a measure designed to assess parental beliefs about infant crying, in a sample of 259 primiparous mothers. Exploratory factor analyses yielded evidence for a five-factor structure to the ICQ, with two factors that may be conceptually viewed as infant-oriented beliefs regarding infant crying (Attachment/Comfort and Crying as Communication) and three factors conceptually reflecting parent-oriented beliefs regarding infant crying (Minimization, Directive Control, and Spoiling). Each of the scales demonstrated strong internal consistency and was associated with concurrent measures of mothers' causal attributions about emotional responses to infant crying. Predictive validity to observed maternal sensitivity at 6 months and mother-reported infant behavioral problems at one year was demonstrated. The importance of a questionnaire method to assess parents' beliefs regarding infant crying in developmental research is discussed and future methodological directions are outlined. PMID:23007097

Haltigan, John D; Leerkes, Esther M; Burney, Regan V; O'Brien, Marion; Supple, Andrew J; Calkins, Susan D

2012-09-21

15

Structural Equation Modeling of Multivariate Time Series  

ERIC Educational Resources Information Center

|The covariance structure of a vector autoregressive process with moving average residuals (VARMA) is derived. It differs from other available expressions for the covariance function of a stationary VARMA process and is compatible with current structural equation methodology. Structural equation modeling programs, such as LISREL, may therefore be…

du Toit, Stephen H. C.; Browne, Michael W.

2007-01-01

16

Systems of fuzzy equations in structural mechanics  

Microsoft Academic Search

Systems of linear and nonlinear equations with fuzzy parameters are relevant to many practical problems arising in structure mechanics, electrical engineering, finance, economics and physics. In this paper three methods for solving such equations are discussed: method for outer interval solution of systems of linear equations depending linearly on interval parameters, fuzzy finite element method proposed by Rama Rao and

Iwona Skalna; M. V. Rama Rao; Andrzej Pownuk

2008-01-01

17

Missing Data Techniques for Structural Equation Modeling  

Microsoft Academic Search

As with other statistical methods, missing data often create major problems for the estimation of structural equation models (SEMs). Conventional methods such as listwise or pairwise deletion generally do a poor job of using all the available information. However, structural equation modelers are fortunate that many programs for estimating SEMs now have maximum likelihood methods for handling missing data in

Paul D. Allison

2003-01-01

18

The Selective Mutism Questionnaire: Measurement Structure and Validity  

PubMed Central

Objective To evaluate the factor structure, reliability, and validity of the 17-item Selective Mutism Questionnaire. Method Diagnostic interviews were administered via telephone to 102 parents of children identified with selective mutism (SM) and 43 parents of children without SM from varying U.S. geographic regions. Children were between the ages of 3 and 11 inclusive and comprised 58% girls and 42% boys. SM diagnoses were determined using the Anxiety Disorders Interview Schedule for Children - Parent Version (ADIS-C/P); SM severity was assessed using the 17-item Selective Mutism Questionnaire (SMQ); and behavioral and affective symptoms were assessed using the Child Behavior Checklist (CBCL). An exploratory factor analysis (EFA) was conducted to investigate the dimensionality of the SMQ and a modified parallel analysis procedure was used to confirm EFA results. Internal consistency, construct validity, and incremental validity were also examined. Results The EFA yielded a 13-item solution consisting of three factors: a) Social Situations Outside of School, b) School Situations, and c) Home and Family Situations. Internal consistency of SMQ factors and total scale ranged from moderate to high. Convergent and incremental validity were also well supported. Conclusions Measure structure findings are consistent with the 3-factor solution found in a previous psychometric evaluation of the SMQ. Results also suggest that the SMQ provides useful and unique information in the prediction of SM phenomenon beyond other child anxiety measures.

Letamendi, Andrea M.; Chavira, Denise A.; Hitchcock, Carla A.; Roesch, Scott C.; Shipon-Blum, Elisa; Stein, Murray B.; Roesch, Scott C.

2010-01-01

19

Revisiting the factor structure of the questionnaire on smoking urges.  

PubMed

This study assessed the factor structure of the Questionnaire on Smoking Urges (QSU), a commonly used assessment of cravings for cigarettes, with a sample of smokers presenting for treatment in a smoking cessation trial. On the basis of previous research, three confirmatory factor analytic models were tested. Model 1 hypothesized a 26-item, 2-factor model using the items reported in the original QSU analysis by S. T. Tiffany and D. J. Drobes (1991). Model 2 hypothesized a 12-item, 2-factor model comprised of the 6 most robust items found in each of the 2 factors of the original factor analysis. Using the 12 items from Model 2, Model 3 hypothesized a 12-item, 1-factor model. The 2nd model was found to fit the data best. Reliability was also tested using values obtained in this 2nd model, and these estimates were found to be reasonably good. Future research directions for the QSU are discussed. PMID:15584799

Toll, Benjamin A; McKee, Sherry A; Krishnan-Sarin, Suchitra; O'malley, Stephanie S

2004-12-01

20

Factor Structure of the Dutch Version of the Childhood Trauma Questionnaire-SF among Female Sex Workers in the Netherlands  

Microsoft Academic Search

In this study, the factor structure of the Childhood Trauma Questionnaire short form (CTQ-SF) in a group of 123 female sex workers in the Netherlands was examined. Structural equation modeling was used to perform the confirmatory factor analysis. The fit between the five-factor model of Bernstein and Fink and the observed empirical model was good. We found a five-factor solution

Stefan Bogaerts; Annelies L. Daalder; Marinus Spreen; Leontien M. Van der Knaap; Jens Henrichs

2011-01-01

21

Systems of fuzzy equations in structural mechanics  

NASA Astrophysics Data System (ADS)

Systems of linear and nonlinear equations with fuzzy parameters are relevant to many practical problems arising in structure mechanics, electrical engineering, finance, economics and physics. In this paper three methods for solving such equations are discussed: method for outer interval solution of systems of linear equations depending linearly on interval parameters, fuzzy finite element method proposed by Rama Rao and sensitivity analysis method. The performance and advantages of presented methods are described with illustrative examples. Extended version of the present paper can be downloaded from the web page of the UTEP [I. Skalna, M.V. Rama Rao, A. Pownuk, Systems of fuzzy equations in structural mechanics, The University of Texas at El Paso, Department of Mathematical Sciences Research Reports Series, , Texas Research Report No. 2007-01, 2007].

Skalna, Iwona; Rama Rao, M. V.; Pownuk, Andrzej

2008-08-01

22

Structural equation model of project planning effectiveness  

Microsoft Academic Search

Previous research studies investigating the impact of situational variables on project planning effectiveness have not examined how the situational variables work together to influence planning effectiveness. A structural equation model (SEM) has been developed for describing and quantifying the influence of situational factors in project environments and organizational characteristics of performing organizations on project planning effectiveness. The individual effects of

M. D. Mainul Islam; Olusegun O. Faniran

2005-01-01

23

Structural Equation Modeling in Behavioral Research  

Cancer.gov

April 27, 2012 10:00 AM - 11:00 AM + Add to Outlook Calendar Date and Time: Friday, April 27th, 10:00-11:00am, EPS/7107 Lecturer:  Natalia Frishman, MD PhD Candidate Iowa State University Print This Page Structural Equation Modeling in Behavioral Research News

24

Using Structural Equation Modeling With Forensic Samples  

Microsoft Academic Search

Because of its many advantages, structural equation modeling (SEM) has been used with increasing frequency in behavioral science, and it is a set of techniques that can be useful in analyzing forensic research data. Issues in SEM, including theory, estimation method, sample size and data requirements, identification, and fit indices are discussed. Using a sample of data from men arrested

Jeffrey C. Meehan; Gregory L. Stuart

2007-01-01

25

Bayesian Model Selection in Structural Equation Models  

Microsoft Academic Search

Abstract A Bayesian approach to model selection for structural equation models is outlined. This enables us to compare individual models, nested or non-nested, and also to search through the (perhaps vast) set of possible models for the best ones. The approach selects several models rather than just one, when appropriate, and so enables us to take account, both informally and

Adrian E. Raftery

1993-01-01

26

Model Comparison of Bayesian Semiparametric and Parametric Structural Equation Models  

Microsoft Academic Search

Structural equation models have wide applications. One of the most important issues in analyzing structural equation models is model comparison. This article proposes a Bayesian model comparison statistic, namely the L?-measure for both semiparametric and parametric structural equation models. For illustration purposes, we consider a Bayesian semiparametric approach for estimation and model comparison in the context of structural equation models

Xin-Yuan Song; Ye-Mao Xia; Jun-Hao Pan; Sik-Yum Lee

2011-01-01

27

Reliability, Validity, and Factor Structure of the Creative Achievement Questionnaire  

Microsoft Academic Search

The Creative Achievement Questionnaire (CAQ) is a new self-report measure of creative achievement that assesses achievement across 10 do- mains of creativity. It was designed to be objective, em- pirically valid, and easy to administer and score. Study 1 established test-retest reliability (r = .81, p < .0001) and internal consistency reliability (? = .96) in a sam- ple of

Shelley Carson; Jordan Peterson; Daniel Higgins

2005-01-01

28

Bayesian Model Comparison of Structural Equation Models  

Microsoft Academic Search

\\u000a Structural equation modeling is a multivariate method for establishing meaningful models to investigate the relationships\\u000a of some latent (causal) and manifest (control) variables with other variables. In the past quarter of a century, it has drawn\\u000a a great deal of attention in psychometrics and sociometrics, both in terms of theoretical developments and practical applications\\u000a (see Bentler and Wu, 2002; Bollen,

Sik-Yum Lee; Xin-Yuan Song

29

Investigating the factor structure of the Questionnaire on Smoking Urges-Brief (QSU-Brief)  

Microsoft Academic Search

This study was designed to investigate the proposed two-factor structure of the 10-item Questionnaire on Smoking Urges-Brief (QSU-Brief) and to provide evidence for the psychometric properties of this questionnaire using the seven-point scoring set from the original QSU study [Tiffany, S.T., Drobes, D.J. (1991). The development and initial validation of a questionnaire on smoking urges. British Journal of Addiction, 86,

Benjamin A. Toll; Nicole A. Katulak; Sherry A. McKee

2006-01-01

30

The Application of Structural Equation Modeling to Maternal Ratings of Twins’ Behavioral and Emotional Problems  

Microsoft Academic Search

The application of structural equation modeling to twin data is used to assess the impact of genetic and environmental factors on children’s behavioral and emotional functioning. The models are applied to the maternal ratings of behavior of a subsample of 515 monozygotic and 749 dizygotic juvenile twin pairs, ages 8 through 16, obtained through mailed questionnaires as part of the

Judy L. Silberg; Marilyn T. Erickson; Joanne M. Meyer; Lindon J. Eaves; Michael L. Rutter; John K. Hewitt

1994-01-01

31

Bayesian Structural Equations Modeling for Ordinal Response Data with Missing Responses and Missing Covariates  

Microsoft Academic Search

Structural equations models (SEMs) have been extensively used to model survey data arising in the fields of sociology, psychology, health, and economics with increasing applications where self assessment questionnaires are the means to collect the data. We propose the SEM for multilevel ordinal response data from a large multilevel survey conducted by the US Veterans Health Administration (VHA). The proposed

Sungduk Kim; Sonali Das; Ming-Hui Chen; Nicholas Warren

2009-01-01

32

Factor Structure and Psychometric Properties of the Young Schema Questionnaire (Short Form) in Chinese Undergraduate Students  

ERIC Educational Resources Information Center

|This study investigated cross-cultural differences in the factor structure and psychometric properties of the Young Schema Questionnaire (short form; YSQ-SF). The participants were 712 Chinese undergraduate students. The total sample was randomly divided into two sub-samples. Exploratory Factor Analysis (EFA) was conducted on questionnaire

Cui, Lixia; Lin, Wenwen; Oei, Tian P. S.

2011-01-01

33

The factor structure of the Strengths and Difficulties Questionnaire (SDQ) in Greek adolescents  

Microsoft Academic Search

BACKGROUND: The Strengths and Difficulties Questionnaire (SDQ) is a practical, economic and user-friendly screening instrument of emotional and behavioural problems in children and adolescents. This study was aimed primarily at evaluating the factor structure of the Greek version of the SDQ. METHODS: A representative nationwide sample of 1,194 adolescents (11 to 17 years old) completed the questionnaire. Confirmatory factor analysis

George Giannakopoulos; Chara Tzavara; Christine Dimitrakaki; Gerasimos Kolaitis; Vasiliki Rotsika; Yannis Tountas

2009-01-01

34

The Smoluchowski diffusion equation for structured macromolecules near structured surfaces  

NASA Astrophysics Data System (ADS)

Beginning with the molecular-based Fokker-Planck equation obtained previously [M. H. Peters, J. Chem. Phys. 110, 528 (1999); J. Stat. Phys. 94, 557 (1999)], the Smoluchowski diffusion equation is derived here to describe the spatial and orientational dynamics of molecularly structured macromolecules near molecularly structured surfaces. The formal scaling and perturbation methods employed allow the establishment of definite limits on the use of the Smoluchowski equation when surfaces are present. It is shown that the Smoluchowski equation reduces to that given previously [D. W. Condiff and J. S. Dahler, J. Chem. Phys. 44, 3988 (1966)] in the absence of external surfaces. A specific example application is given involving a spherical macromolecule with electrostatic charge segments near a planar surface with an arbitrary charge distribution. Finally, we show that the short-time solution to the Smoluchowski equation obtained here yields a Brownian dynamics method consistent with that given previously [E. Dickinson, S. A. Allison, and J. A. McCammon, J. Chem. Soc. Faraday Trans. 2 81, 591 (1985)] for orientable, interacting Brownian particles. This study has applications to problems involving site-specific adsorption of orientable, structured Brownian particles, such as association or adsorption of biological macromolecules to cellular surfaces and enzyme-substrate docking kinetics, to name a few.

Peters, Michael H.

2000-03-01

35

Model Comparison of Bayesian Semiparametric and Parametric Structural Equation Models  

ERIC Educational Resources Information Center

|Structural equation models have wide applications. One of the most important issues in analyzing structural equation models is model comparison. This article proposes a Bayesian model comparison statistic, namely the "L[subscript nu]"-measure for both semiparametric and parametric structural equation models. For illustration purposes, we consider…

Song, Xin-Yuan; Xia, Ye-Mao; Pan, Jun-Hao; Lee, Sik-Yum

2011-01-01

36

Structural Analysis of the Resident Assistant Cultural Diversity Questionnaire  

ERIC Educational Resources Information Center

|This study investigated the five-factor structure of the Resident Assistant Cultural Diversity (RACD) instrument, which assesses resident assistant (RA) confidence in addressing issues of cultural diversity in college and university residence halls. The instrument has five components that explore RA confidence: (1) belief in the need for cultural…

Johnson, Vanessa D.; Kang, Young-Shin; Thompson, George F.

2011-01-01

37

Hydrodynamic equations for semiconductors with nonparabolic band structure  

Microsoft Academic Search

A system of generalized hydrodynamic equations is derived from Boltzmann's transport equation for semiconductors without the assumption of a parabolic band structure. After some simplifications these equations can be arranged in such a way that their structure is similar to that of the well-known conventional ones. For this purpose the quantity carrier temperature is redefined and five relaxation times have

Rainer Thoma; Axel Emunds; Bernd Meinerzhagen; Hermann-Josef Peifer; Walter L. Engl

1991-01-01

38

Testing Structural Invariance of the Achievement Goal Questionnaire in American, Chinese, and Dutch College Students  

ERIC Educational Resources Information Center

|This study investigates the structural invariance of the Achievement Goal Questionnaire (AGQ) in American, Chinese, and Dutch college students. Using confirmatory factor analyses (CFA), the authors found evidence for the four-factor structure of achievement goals in all three samples. Subsequent multigroup CFAs supported structural invariance of…

Sun, Huaping; Hernandez, Diley

2012-01-01

39

Structural equation modeling in environmental risk assessment.  

PubMed Central

Environmental epidemiology requires effective models that take individual observations of environmental factors and connect them into meaningful patterns. Single-factor relationships have given way to multivariable analyses; simple additive models have been augmented by multiplicative (logistic) models. Each of these steps has produced greater enlightenment and understanding. Models that allow for factors causing outputs that can affect later outputs with putative causation working at several different time points (e.g., linkage) are not commonly used in the environmental literature. Structural equation models are a class of covariance structure models that have been used extensively in economics/business and social science but are still little used in the realm of biostatistics. Path analysis in genetic studies is one simplified form of this class of models. We have been using these models in a study of the health and development of infants who have been exposed to lead in utero and in the postnatal home environment. These models require as input the directionality of the relationship and then produce fitted models for multiple inputs causing each factor and the opportunity to have outputs serve as input variables into the next phase of the simultaneously fitted model. Some examples of these models from our research are presented to increase familiarity with this class of models. Use of these models can provide insight into the effect of changing an environmental factor when assessing risk. The usual cautions concerning believing a model, believing causation has been proven, and the assumptions that are required for each model are operative.

Buncher, C R; Succop, P A; Dietrich, K N

1991-01-01

40

Reliability, validity and structure of the Adolescent Decision Making Questionnaire among adolescents in The Netherlands  

Microsoft Academic Search

The reliability, validity and structure of the 30 item Adolescent Decision Making Questionnaire were investigated in a sample consisting of 1642 Dutch adolescents. The original structure of five subscales was not found to be sufficient in our data. Therefore a revised ADMQ was proposed, with four subscales and 22 items. A cross validation study proved that this revised ADMQ was

J. Tuinstra; F. L. P. van Sonderen; J. W. Groothoff; D. Post

2000-01-01

41

Learning Structural Equation Models for fMRI  

Microsoft Academic Search

Structural equation models can be seen as an extension of Gaussian belief net- works to cyclic graphs, and we show they can be understood generatively as the model for the joint distribution of long term average equilibrium activity of Gaus- sian dynamic belief networks. Most use of structural equation models in fMRI involves postulating a particular structure and comparing learnt

Amos J. Storkey; Enrico Simonotto; Heather Whalley; Stephen Lawrie; Lawrence Murray; David Mcgonigle

2006-01-01

42

Mathematical structure of transport equations for multispecies flows  

Microsoft Academic Search

In this review we attempt to present a unified picture of transport in multispecies gas mixtures. To accomplish this task, it is necessary to outline the mathematical structure of the transport equations. Starting from Boltzmann's equation, we derive a general system of transport equations using an approach that is valid for flow situations in which there are large temperature and

R. W. ScitJsI

1977-01-01

43

Mathematical structure of transport equations for multispecies flows  

Microsoft Academic Search

A unified picture of transport in multispecies gas mixtures is presented, and the mathematical structure of transport equations is outlined. A general system of transport equations is derived in terms of Boltzmann's equation by consideration of flow situations in which there are large temperature and drift velocity differences between the interacting species. The procedure for obtaining a closed set of

R. W. Schunk

1977-01-01

44

The Hamiltonian Structures of ?-Equations Related to Periodic Peakons  

NASA Astrophysics Data System (ADS)

The hierarchies of the ?-Camassa—Holm, two-component ?-Camassa—Holm and ?-modified Camassa—Holm equations are constructed from bi-Hamiltonian structures of the Korteweg-de Vries equation, the Ito equation and the modified Korteweg-de Vries equation. The key Hamiltonian operator that includes ? is ?x? — ?3x, and the inner product used to define the Jacobi identity of the Hamiltonian operators is defined on the unit circle S1.

Fu, Wei; Zhang, Da-Jun

2013-08-01

45

A STRUCTURAL EQUATION MODEL FOR ROAD ACCIDENT ANALYSIS  

Microsoft Academic Search

In this paper a tool for effecting road accident analysis is proposed. Specifically, a structural equation model is introduced. Structural equation modelling (SEM) is a multivariate technique combining regression, factor analysis and analysis of variance in order to estimate interrelated dependence relationships simultaneously. This approach allows the modelling of a phenomenon by considering both the unobserved \\

46

Model comparison of nonlinear structural equation models with fixed covariates  

Microsoft Academic Search

Recently, it has been recognized that the commonly used linear structural equation model is inadequate to deal with some complicated substantive theory. A new nonlinear structural equation model with fixed covariates is proposed in this article. A procedure, which utilizes the powerful path sampling for computing the Bayes factor, is developed for model comparison. In the implementation, the required random

Sik-Yum Lee; Xin-Yuan Song

2003-01-01

47

A Bayesian analysis on time series structural equation models  

Microsoft Academic Search

Structural equation models (SEM) have been extensively used in behavioral, social, and psychological research to model relations between the latent variables and the observations. Most software packages for the fitting of SEM rely on frequentist methods. Traditional models and software are not appropriate for analysis of the dependent observations such as time-series data. In this study, a structural equation model

Yi-Fu Wang; Tsai-Hung Fan

2011-01-01

48

Sensitivity of rocky planet structures to the equation of state  

SciTech Connect

Structures were calculated for Mercury, Venus, Earth, the Moon, and Mars, using a core-mantle model and adjusting the core radius to reproduce the observed mass and diameter of each body. Structures were calculated using Fe and basalt equations of state of different degrees of sophistication for the core and mantle. The choice of equation of state had a significant effect on the inferred structure. For each structure, the moment of inertia ratio was calculated and compared with observed values. Linear Grueneisen equations of state fitted to limited portions of shock data reproduced the observed moments of inertia significantly better than did more detailed equations of state incorporating phase transitions, presumably reflecting the actual compositions of the bodies. The linear Grueneisen equations of state and corresponding structures seem however to be a reasonable starting point for comparative simulations of large-scale astrophysical impacts.

Swift, D C

2009-06-10

49

Factor Structure and Measurement Invariance of the Cognitive Failures Questionnaire across the Adult Life Span  

ERIC Educational Resources Information Center

The Cognitive Failures Questionnaire (CFQ) is designed to assess a person's proneness to committing cognitive slips and errors in the completion of everyday tasks. Although the CFQ is a widely used instrument, its factor structure remains an issue of scientific debate. The present study used data of a representative sample (N = 1,303, 24-83 years…

Rast, Philippe; Zimprich, Daniel; Van Boxtel, Martin; Jolles, Jellemer

2009-01-01

50

Revisiting the Factor Structure of the Strengths and Difficulties Questionnaire: United States, 2001.  

ERIC Educational Resources Information Center

|Objective: The Strengths and Difficulties Questionnaire is a 25-item instrument developed to assess emotional and behavioral problems. The current study attempted to replicate previous European structural analyses and to describe the latent dimensions that underlie responses to the parent-reported version of the Strengths and Difficulties…

Dickey, Wayne C.; Blumberg, Stephen J.

2004-01-01

51

Factor Structure of the Children's Behavior Questionnaire in Children with Williams Syndrome  

ERIC Educational Resources Information Center

|To examine the factor structure of temperament in 5-10-year-olds with Williams syndrome, an exploratory factor analysis was conducted on the responses of parents of 192 children on the children's behavior questionnaire. Four factors were identified. Two corresponded to factors reported for typically developing children: effortful control and…

Leyfer, Ovsanna; John, Angela E.; Woodruff-Borden, Janet; Mervis, Carolyn B.

2012-01-01

52

Mirror mode structures observed in the dawn-side magnetosheath by Equator-S  

Microsoft Academic Search

The Equator-S satellite was ideally positioned to make magnetic field observations in the dawn-side magnetosheath, relatively close to the magnetopause. The magnetosheath data were particularly rich in compressional signatures, consistent with mirror mode structures, which occurred during ~30% of orbits crossing into the magnetosheath. In most, although not all cases, strongly compressive signatures extended up to the magnetopause boundary, with

E. A. Lucek; M. W. Dunlop; A. Balogh; P. Cargill; W. Baumjohann; E. Georgescu; G. Haerendel; K.-H. Fornacon

1999-01-01

53

Gaussian Process Structural Equation Models with Latent Variables  

Microsoft Academic Search

In a variety of disciplines such as social sciences, psychology, medicine and\\u000aeconomics, the recorded data are considered to be noisy measurements of latent\\u000avariables connected by some causal structure. This corresponds to a family of\\u000agraphical models known as the structural equation model with latent variables.\\u000aWhile linear non-Gaussian variants have been well-studied, inference in\\u000anonparametric structural equation models

Ricardo Silva; Robert B. Gramacy

2010-01-01

54

Hamiltonian structures for the Ostrovsky-Vakhnenko equation  

NASA Astrophysics Data System (ADS)

We obtain a bi-Hamiltonian formulation for the Ostrovsky-Vakhnenko (OV) equation using its higher order symmetry and a new transformation to the Caudrey-Dodd-Gibbon-Sawada-Kotera equation. Central to this derivation is the relation between Hamiltonian structures when dependent and independent variables are transformed.

Brunelli, J. C.; Sakovich, S.

2013-01-01

55

Structure of the amplitude equation of the climate.  

National Technical Information Service (NTIS)

The structure of the 'amplitude equation', a new dynamic equation on the seasonal time scale is derived, in which the weather scales may be treated statistically. The elsewhere-introduced climate-specific seasonally smoothed amplitudes and phases of the F...

A. Hauschild

1999-01-01

56

Prolongation Structure of the Equation Studied by Qiao  

NASA Astrophysics Data System (ADS)

The prolongation structure technique of Wahlquist and Estanbrook is improved and applied to a new equation proposed by Z.J. Qiao [J. Math. Phys. 48 (2007) 082701]. Two potentials and two pseudopotentials are obtained, from which a new type of inverse scattering problem, Lax equations, and infinite number of conservation laws are obtained.

Yang, Yun-Qing; Chen, Yong

2011-09-01

57

A structural equation model of depression and the defense system factors: A survey among Chinese college students  

Microsoft Academic Search

Questionnaires were administered to a large sample of subjects (1363 Chinese college students), to evaluate the mediating risk factors in the defense system of depression, including personality, coping skills, interpersonal context and family environment. Structural equation modeling (SEM) was used to analyze a total of 12 variables in order to understand how they interact with each other. Eysenck's Neuroticism, Extraversion,

Jue Jin; Yi-Yuan Tang; Yinghua Ma; Shipin Lv; Ying Bai; Hangli Zhang

2009-01-01

58

The Big Five Personality Traits and Uses of Music: A Replication in Malaysia Using Structural Equation Modeling  

Microsoft Academic Search

The current study set out to replicate and extend a recent paper (Chamorro-Premuzic & Furnham, 2007) on personality and uses of music using structural equation modeling. Responses to questionnaire data from 227 Malaysian university students showed that, in line with our hypotheses, individuals higher in Neuroticism were more likely to use music for emotional regulation (influencing their mood states), Extraversion

Tomas Chamorro-Premuzic; Viren Swami; Adrian Furnham; Ismail Maakip

2009-01-01

59

USING STRUCTURAL EQUATION MODELING TO INVESTIGATE RELATIONSHIPS AMONG ECOLOGICAL VARIABLES  

EPA Science Inventory

This paper gives an introductory account of Structural Equation Modeling (SEM) and demonstrates its application using LISREL< with a model utilizing environmental data. Using nine EMAP data variables, we analyzed their correlation matrix with an SEM model. The model characterized...

60

Investigating the factor structure of the Questionnaire on Smoking Urges-Brief (QSU-Brief).  

PubMed

This study was designed to investigate the proposed two-factor structure of the 10-item Questionnaire on Smoking Urges-Brief (QSU-Brief) and to provide evidence for the psychometric properties of this questionnaire using the seven-point scoring set from the original QSU study [Tiffany, S.T., Drobes, D.J. (1991). The development and initial validation of a questionnaire on smoking urges. British Journal of Addiction, 86, 1467-1476.]. The study sample (N=576) was comprised of smokers presenting for treatment. Although an initial exploratory factor analysis appeared to replicate the original factor analytic findings of Cox et al. [Cox, L.S., Tiffany, S.T., Christen, A.G. (2001). Evaluation of the brief questionnaire of smoking urges (QSU-Brief) in laboratory and clinical settings. Nicotine and Tobacco Research, 3, 7-16.], when subjected to confirmatory factor analyses, a five-item, two-factor model using the most robust items from the original QSU-Brief factor analysis was the best explanation of the data in the present study. Good internal consistency reliability estimates were also obtained with this model. These results suggest that this shortened form of the QSU-Brief can be used with the original seven-point scoring set as a reliable assessment of the dual nature of smoking urges in a treatment-seeking population. PMID:16226843

Toll, Benjamin A; Katulak, Nicole A; McKee, Sherry A

2005-10-14

61

Testing the structural and cross-cultural validity of the KIDSCREEN-27 quality of life questionnaire  

Microsoft Academic Search

Objectives  The aim of this study is to assess the structural and cross-cultural validity of the KIDSCREEN-27 questionnaire.\\u000a \\u000a \\u000a \\u000a Methods  The 27-item version of the KIDSCREEN instrument was derived from a longer 52-item version and was administered to young people\\u000a aged 8–18 years in 13 European countries in a cross-sectional survey. Structural and cross-cultural validity were tested using\\u000a multitrait multi-item analysis, exploratory and confirmatory

Stephane Robitail; Ulrike Ravens-Sieberer; Marie-Claude Simeoni; Luis Rajmil; Jeanet Bruil; Mick Power; Wolfgang Duer; Bernhard Cloetta; Ladislav Czemy; Joanna Mazur; Agnes Czimbalmos; Yannis Tountas; Curt Hagquist; Jean Kilroe; Pascal Auquier

2007-01-01

62

Linear structural equations with latent variables  

Microsoft Academic Search

An interdependent multivariate linear relations model based on manifest, measured variables as well as unmeasured and unmeasurable latent variables is developed. The latent variables include primary or residual common factors of any order as well as unique factors. The model has a simpler parametric structure than previous models, but it is designed to accommodate a wider range of applications via

P. M. Bentler

1980-01-01

63

Lagrangian and Hamiltonian structures for the constant astigmatism equation  

NASA Astrophysics Data System (ADS)

In this paper we found a Lagrangian representation and corresponding Hamiltonian structure for the constant astigmatism equation. Utilizing this Hamiltonian structure and extra conservation law densities we construct a first evolution commuting flow of the third order. We also apply the recursion operator and present a second Hamiltonian structure. This bi-Hamiltonian structure allows us to replicate infinitely many local commuting flows and corresponding local conservation law densities.

Pavlov, Maxim V.; Zykov, Sergej A.

2013-10-01

64

Exact coherent structures for coupled integrable dispersionless equations  

NASA Astrophysics Data System (ADS)

In this paper, the singular manifold method is applied to search coherent structures in an analytical form for the coupled integrable dispersionless equations. The Generalized solutions have been derived to the coupled integrable dispersionless equations, where the solutions are determined by the singular variable totally. With the aid of symbolic computation and plot representation of Maple, some coherent structures expressed in terms of new forms, such as solitoffs and breather lattice structures, have been illustrated by means of arbitrary functions in the analytical forms.

Fu, Zuntao; Mao, Jiangyu

2012-06-01

65

Musculoskeletal pain illness perceptions: Factor structure of the Illness Perceptions Questionnaire-Revised  

PubMed Central

Background: The Revised Illness Perceptions Questionnaire (IPQ-R) is commonly used to measure illness perceptions. We tested whether the structure of the IPQ-R was appropriate for use with primary care musculoskeletal pain patients. Methods: Confirmatory (C) and exploratory (E) factor analyses (FA) were used to test whether the structure of the IPQ-R was supported for patients with knee pain (n = 393), hand pain (n = 2113) and back pain (n = 1591). CFA was used to test whether the timeline acute/chronic, timeline cyclical, consequences, personal control, treatment control, illness coherence and emotional representation dimensions of the IPQ-R were distinct; EFA was used to explore potential structure for patients’ views on the cause of their condition. Results: Goodness-of-fit indices for the CFA were below our criteria for good model fit. Removal of six items from the model improved model fit, but our criteria for good model fit was still not achieved. An interpretable factor solution could not be determined for the causal items on the questionnaire. Conclusions: Our data show limited evidence that the seven dimensions of the IPQ-R are distinct. A clear structure for the causal items was not determined. Further work is needed to develop the IPQ-R for use with primary care musculoskeletal pain patients.

Nicholls, Elaine E.; Hill, Susan; Foster, Nadine E.

2012-01-01

66

Structural equation modelling and regression analysis in tourism research  

Microsoft Academic Search

This paper explores the concept of structural equation modelling (SEM) and discusses the steps which researchers should follow when using this technique. This involves the development of a theoretical model, testing of a confirmatory measurement model, and evaluating the structural model with hypothesised path relations. For the benefit of readers, the discussion is supported by an illustration of a theoretical

Robin Nunkoo; Haywantee Ramkissoon

2011-01-01

67

Bayesian Semiparametric Structural Equation Models with Latent Variables  

ERIC Educational Resources Information Center

|Structural equation models (SEMs) with latent variables are widely useful for sparse covariance structure modeling and for inferring relationships among latent variables. Bayesian SEMs are appealing in allowing for the incorporation of prior information and in providing exact posterior distributions of unknowns, including the latent variables. In…

Yang, Mingan; Dunson, David B.

2010-01-01

68

Structural Equation Modelling: A Primer for Music Education Researchers  

ERIC Educational Resources Information Center

|Structural equation modelling (SEM) is a method for analysis of multivariate data from both non-experimental and experimental research. The method combines a structural model linking latent variables and a measurement model linking observed variables with latent variables. Its use in social science and educational research has grown since the…

Teo, Timothy

2010-01-01

69

Exploring ecological patterns with structural equation modeling and Bayesian analysis  

Microsoft Academic Search

Structural equation modeling is a multivariate statistical method that allows evaluation of a network of relationships between manifest and latent variables. In this statistical technique, preconceptualizations that reflect research questions or existing knowledge of system structure create the initial framework for model development, while both direct and indirect effects and measurement errors are considered. Given the interesting features of this

G. B. Arhonditsis; C. A. Stow; L. J. Steinberg; M. A. Kenney; R. C. Lathrop; S. J. McBride; K. H. Reckhow

2006-01-01

70

Sensitivity of Rocky Planet Structures to the Equation of State.  

National Technical Information Service (NTIS)

Structures were calculated for Mercury, Venus, Earth, the Moon, and Mars, using a core-mantle model and adjusting the core radius to reproduce the observed mass and diameter of each body. Structures were calculated using Fe and basalt equations of state o...

D. C. Swift

2009-01-01

71

Bi-Hamiltonian structure of an asymmetric heavenly equation  

NASA Astrophysics Data System (ADS)

In the paper of Sheftel and Malykh (2009 J. Phys. A: Math. Theor. 42 395202) on the classification of second-order PDEs with four independent variables that possess partner symmetries, an asymmetric heavenly equation appears as one of the canonical equations admitting partner symmetries. Here, for the asymmetric heavenly equation formulated in a two-component form, we present the Lax pair of Olver-Ibragimov-Shabat type and obtain its multi-Hamiltonian structure. Therefore, by Magri’s theorem, it is a completely integrable bi-Hamiltonian system in four dimensions.

Yaz?c?, D.

2011-12-01

72

On the structure of gravitational U4-field equations  

NASA Astrophysics Data System (ADS)

The exterior calculus is used, together with some decomposition techniques within this formalism, in order to make the generally very complex structure of the U sub 4-field equations of gravity more transparent. As a result of this treatment, some of the equations acquire a comparatively simple form which may be given in several equivalent versions according to various requirements. Attention is also given to models in various dimensions, giving classes of solutions under certain assumptions.

Wallner, R. P.

1985-11-01

73

The factor structure of the Strengths and Difficulties Questionnaire (SDQ) in Greek adolescents  

PubMed Central

Background The Strengths and Difficulties Questionnaire (SDQ) is a practical, economic and user-friendly screening instrument of emotional and behavioural problems in children and adolescents. This study was aimed primarily at evaluating the factor structure of the Greek version of the SDQ. Methods A representative nationwide sample of 1,194 adolescents (11 to 17 years old) completed the questionnaire. Confirmatory factor analysis (CFA) was conducted to assess the factor structure of the SDQ. Results CFA supported the original five-factor structure. The modification of the model provided some improvements. Internal consistency was acceptable for total difficulties, emotional symptoms and prosocial behaviour scale, moderate for hyperactivity/inattention scale and inadequate for peer and conduct problems scale. Older adolescents (aged 15 to 17 years) reported more hyperactivity/inattention and conduct problems than younger ones (aged 11 to 14 years) and girls reported more emotional symptoms and less prosocial behaviour problems than boys. Adolescents of low socioeconomic status (SES) reported more difficulties than those of medium and high SES. Conclusion The Greek SDQ could be potentially considered as a community-wide screening instrument for adolescents' emotional and behavioural problems.

Giannakopoulos, George; Tzavara, Chara; Dimitrakaki, Christine; Kolaitis, Gerasimos; Rotsika, Vasiliki; Tountas, Yannis

2009-01-01

74

Fitting multivariage normal finite mixtures subject to structural equation modeling  

Microsoft Academic Search

This paper is about fitting multivariate normal mixture distributions subject to structural equation modeling. The general\\u000a model comprises common factor and structural regression models. The introduction of covariance and mean structure models reduces\\u000a the number of parameters to be estimated in fitting the mixture and enables one to investigate a variety of substantive hypotheses\\u000a concerning the differences between the components

Conor V. Dolan

1998-01-01

75

Sensitivity Analysis in Structural Equation Models: Cases and Their Influence  

ERIC Educational Resources Information Center

|The detection of outliers and influential observations is routine practice in linear regression. Despite ongoing extensions and development of case diagnostics in structural equation models (SEM), their application has received limited attention and understanding in practice. The use of case diagnostics informs analysts of the uncertainty of…

Pek, Jolynn; MacCallum, Robert C.

2011-01-01

76

Effect analysis and causation in linear structural equation models  

Microsoft Academic Search

This paper considers total and direct effects in linear structural equation models. Adopting a causal perspective that is implicit in much of the literature on the subject, the paper concludes that in many instances the effects do not admit the interpretations imparted in the literature. Drawing a distinction between concomitants and factors, the paper concludes that a concomitant has neither

Michael E. Sobel

1990-01-01

77

Peer Victimization, Student Engagement, and School Attendance: Structural Equation Models  

ERIC Educational Resources Information Center

|Survey data from a study of 6th grade students in Colorado (n=860) were used to estimate structural equation models in which peer victimization types were hypothesized to have significant relationships with both student engagement and attendance. Then, student engagement and attendance variables were hypothesized to have significant effects on…

Dunkle, Jason Benjamin

2009-01-01

78

Evaluating Interventions with Multimethod Data: A Structural Equation Modeling Approach  

ERIC Educational Resources Information Center

|In many intervention and evaluation studies, outcome variables are assessed using a multimethod approach comparing multiple groups over time. In this article, we show how evaluation data obtained from a complex multitrait-multimethod-multioccasion-multigroup design can be analyzed with structural equation models. In particular, we show how the…

Crayen, Claudia; Geiser, Christian; Scheithauer, Herbert; Eid, Michael

2011-01-01

79

Structural Equations and Causal Explanations: Some Challenges for Causal SEM  

ERIC Educational Resources Information Center

|One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

Markus, Keith A.

2010-01-01

80

A Structural Equation Model of Conceptual Change in Physics  

ERIC Educational Resources Information Center

|A model of conceptual change in physics was tested on introductory-level, college physics students. Structural equation modeling was used to test hypothesized relationships among variables linked to conceptual change in physics including an approach goal orientation, need for cognition, motivation, and course grade. Conceptual change in physics…

Taasoobshirazi, Gita; Sinatra, Gale M.

2011-01-01

81

Evaluating Interventions with Multimethod Data: A Structural Equation Modeling Approach  

ERIC Educational Resources Information Center

In many intervention and evaluation studies, outcome variables are assessed using a multimethod approach comparing multiple groups over time. In this article, we show how evaluation data obtained from a complex multitrait-multimethod-multioccasion-multigroup design can be analyzed with structural equation models. In particular, we show how the…

Crayen, Claudia; Geiser, Christian; Scheithauer, Herbert; Eid, Michael

2011-01-01

82

Play Context, Commitment, and Dating Violence: A Structural Equation Model  

ERIC Educational Resources Information Center

|This study develops a structural equation model to describe the effect of two groups of factors (type of commitment and play context) on the violence experienced during intimate partner conflict. After contrasting the model in adolescents and university students, we have confirmed that aggressive play and the simulation of jealousy and anger…

Gonzalez-Mendez, Rosaura; Hernandez-Cabrera, Juan Andres

2009-01-01

83

Stress and strain in teaching: A structural equation approach  

Microsoft Academic Search

Background. School teaching seems to be particularly stressful. The stress model of Lazarus and colleagues and its adaptation to educational settings by Kyriacou and Sutcliffe is the basis for an analysis of antecedents and consequences of teacher stress. Aims. The first aim was to test the theoretical model of teacher stress on a large sample using structural equation statistics (study

Rolf van Dick; Ulrich Wagner

2001-01-01

84

Bayesian Analysis of Structural Effects in an Ordered Equation System  

Microsoft Academic Search

We describe a new simulation-based algorithm for Bayesian estimation of structural effects in models where the outcome of interest and an endogenous treatment variable are ordered. Our algorithm makes use of a reparameterization, suggested by Nandram and Chen (1996) in the context of a single equation ordered-probit model, which significantly improves the mixing of the standard Gibbs sampler. We illustrate

Mingliang Li; Justin Tobias

2005-01-01

85

Bayesian Analysis of Structural Effects in an Ordered Equation System  

Microsoft Academic Search

We describe a new simulation-based algorithm for Bayesian estimation of structural effects in models where the outcome of interest and an endogenous treatment variable are ordered. Our algorithm makes use of a reparameterization, suggested by Nandram and Chen (1996) in the context of a single equation ordered-probit model, which significantly improves the mixing of the standard Gibbs sampler. We illustrate

Mingliang Li; Justin L. Tobias

2006-01-01

86

Advancing operations management theory using exploratory structural equation modelling techniques  

Microsoft Academic Search

The structural equation modelling (SEM) technique has been touted as a useful tool for tightening links between theoretical and empirical operations management (OM) research. Despite SEM's increasing prominence in the field, leading scholars continue to call for a deeper infusion of theory into empirical OM research. To strengthen ties between theory and analysis in OM research, this study evaluates previous

Nicholas Roberts; Jason Bennett Thatcher; Varun Grover

2010-01-01

87

Hopes and Cautions in Implementing Bayesian Structural Equation Modeling  

ERIC Educational Resources Information Center

Muthen and Asparouhov (2012) have proposed and demonstrated an approach to model specification and estimation in structural equation modeling (SEM) using Bayesian methods. Their contribution builds on previous work in this area by (a) focusing on the translation of conventional SEM models into a Bayesian framework wherein parameters fixed at zero…

MacCallum, Robert C.; Edwards, Michael C.; Cai, Li

2012-01-01

88

Robust Structural Equation Modeling with Missing Data and Auxiliary Variables  

ERIC Educational Resources Information Center

|The paper develops a two-stage robust procedure for structural equation modeling (SEM) and an R package "rsem" to facilitate the use of the procedure by applied researchers. In the first stage, M-estimates of the saturated mean vector and covariance matrix of all variables are obtained. Those corresponding to the substantive variables are then…

Yuan, Ke-Hai; Zhang, Zhiyong

2012-01-01

89

Bayesian Data-Model Fit Assessment for Structural Equation Modeling  

Microsoft Academic Search

Bayesian approaches to modeling are receiving an increasing amount of attention in the areas of model construction and estimation in factor analysis, structural equation modeling (SEM), and related latent variable models. However, model diagnostics and model criticism remain relatively understudied aspects of Bayesian SEM. This article describes and illustrates key features of Bayesian approaches to model diagnostics and assessing data–model

Roy Levy

2011-01-01

90

Bayesian Analysis of Structural Equation Model with Fixed Covariates.  

ERIC Educational Resources Information Center

Extends the LISREL model to incorporate fixed covariates at both the measurement and the structural equations of the model, establishing a Bayesian procedure with conjugate type prior distributions. Illustrates the efficiency of the algorithm and presents a goodness of fit statistic for assessing the proposed model. (SLD)

Lee, Sik-Yum; Shi, Jian-Qing

2000-01-01

91

Bayesian estimation and testing of structural equation models  

Microsoft Academic Search

The Gibbs sampler can be used to obtain samples of arbitrary size from the posterior distribution over the parameters of a structural equation model (SEM) given covariance data and a prior distribution over the parameters. Point estimates, standard deviations and interval estimates for the parameters can be computed from these samples. If the prior distribution over the parameters is uninformative,

Richard Scheines; Herbert Hoijtink; Anne Boomsma

1999-01-01

92

Modeling Dynamic Functional Neuroimaging Data Using Structural Equation Modeling  

Microsoft Academic Search

The aims of this study were to present a method for developing a path analytic network model using data acquired from positron emission tomography. Regions of interest within the human brain were identified through quantitative activation likelihood estimation meta-analysis. Using this information, a “true” or population path model was then developed using Bayesian structural equation modeling. To evaluate the impact

Larry R. Price; Angela R. Laird; Peter T. Fox; Roger J. Ingham

2009-01-01

93

Classiflcation of structural equation models based on fuzzy regression  

Microsoft Academic Search

Structural equation models (SEM) are reference techniques for measuring cause- efiect relationships in complex systems. In many real cases observations are a priori grouped into homogeneous segments according to a speciflc characteristic, so that difierent models can be assessed for each segment. The present paper proposes to adopt an Euclidean metric based on the model parameters in order to determine

R. Romano; F. Palumbo

2006-01-01

94

Multilevel Analysis of Structural Equation Models via the EM Algorithm.  

ERIC Educational Resources Information Center

The question of how to analyze unbalanced hierarchical data generated from structural equation models has been a common problem for researchers and analysts. Among difficulties plaguing statistical modeling are estimation bias due to measurement error and the estimation of the effects of the individual's hierarchical social milieu. This paper…

Jo, See-Heyon

95

A Bayesian Approach for Analyzing Longitudinal Structural Equation Models  

Microsoft Academic Search

This article considers a Bayesian approach for analyzing a longitudinal 2-level nonlinear structural equation model with covariates, and mixed continuous and ordered categorical variables. The first-level model is formulated for measures taken at each time point nested within individuals for investigating their characteristics that are dynamically changed over time. The second level is defined for individuals for assessing their characteristics

Xin-Yuan Song; Zhao-Hua Lu; Yih-Ing Hser; Sik-Yum Lee

2011-01-01

96

Bayesian structural equation modeling method for hierarchical model validation  

Microsoft Academic Search

A building block approach to model validation may proceed through various levels, such as material to component to subsystem to system, comparing model predictions with experimental observations at each level. Usually, experimental data becomes scarce as one proceeds from lower to higher levels. This paper presents a structural equation modeling approach to make use of the lower-level data for higher-level

Xiaomo Jiang; Sankaran Mahadevan

2009-01-01

97

Hopes and Cautions in Implementing Bayesian Structural Equation Modeling  

Microsoft Academic Search

Muthén and Asparouhov (2012) have proposed and demonstrated an approach to model specification and estimation in structural equation modeling (SEM) using Bayesian methods. Their contribution builds on previous work in this area by (a) focusing on the translation of conventional SEM models into a Bayesian framework wherein parameters fixed at zero in a conventional model can be respecified using small-variance

Robert C. MacCallum; Michael C. Edwards; Li Cai

2012-01-01

98

Hyper-parameter selection in Bayesian structural equation models  

Microsoft Academic Search

In the structural equation models, the maximum likelihood estimates of error variances can often turn out to be zero or negative. In order to overcome this prob- lem, we take a Bayesian approach by specifying a prior distribution for variances of error variables. Crucial issues in this modeling procedure include the selection of hyper-parameters in the prior distribution. Choosing these

Kei Hirose; Shuichi Kawano; Daisuke Miike; Sadanori Konishi

99

Interactions of Latent Variables in Structural Equation Models.  

ERIC Educational Resources Information Center

|Provides a discussion of an alternative two-stage least squares (2SLS) technique to include interactions of latent variables in structural equation models. The method requires selection of instrumental variables, and rules for selection are presented. An empirical example and Statistical Analysis System programs are presented. (SLD)|

Bollen, Kenneth A.; Paxton, Pamela

1998-01-01

100

A Bayesian Approach for Analyzing Longitudinal Structural Equation Models  

ERIC Educational Resources Information Center

|This article considers a Bayesian approach for analyzing a longitudinal 2-level nonlinear structural equation model with covariates, and mixed continuous and ordered categorical variables. The first-level model is formulated for measures taken at each time point nested within individuals for investigating their characteristics that are…

Song, Xin-Yuan; Lu, Zhao-Hua; Hser, Yih-Ing; Lee, Sik-Yum

2011-01-01

101

Principles and practice in reporting structural equation analyses  

Microsoft Academic Search

Principles for reporting analyses using structural equation modeling are reviewed, with the goal of supplying readers with complete and accurate information. It is recommended that every report give a detailed justification of the model used, along with plausible alternatives and an account of identifiability. Nonnormality and missing data problems should also be addressed. A complete set of parameters and their

Roderick P. McDonald; Moon-Ho Ringo Ho

2002-01-01

102

A Structural Equation Model for Predicting Business Student Performance  

ERIC Educational Resources Information Center

In this study, the authors developed a structural equation model that accounted for 79% of the variability of a student's final grade point average by using a sample size of 147 students. The model is based on student grades in 4 foundational business courses: introduction to business, macroeconomics, statistics, and using databases. Educators and…

Pomykalski, James J.; Dion, Paul; Brock, James L.

2008-01-01

103

A Structural Equation Model for Predicting Business Student Performance  

ERIC Educational Resources Information Center

|In this study, the authors developed a structural equation model that accounted for 79% of the variability of a student's final grade point average by using a sample size of 147 students. The model is based on student grades in 4 foundational business courses: introduction to business, macroeconomics, statistics, and using databases. Educators…

Pomykalski, James J.; Dion, Paul; Brock, James L.

2008-01-01

104

Coherent structures theory for the generalized Kuramoto-Sivashinsky equation  

NASA Astrophysics Data System (ADS)

We examine coherent structures interaction and formation of bound states in active-dispersive-dissipative nonlinear media. A prototype for such media is a simple weakly nonlinear model, the generalized Kuramoto-Sivashinsky (gKS) equation, that retains the fundamental mechanisms of any nonlinear process involving wave evolution, namely, a dominant nonlinearity, instability, stability and dispersion. We develop a weak interaction theory for the solitary pulses of the gKS equation by representing the solution as a superposition of the pulses and an overlap function. We derive a linearized equation for the overlap function in the vicinity of each pulse and project the dynamics of this function onto the discrete part of the spectrum of the linearized interaction operator. This leads to a coupled system of ordinary differential equations describing the evolution of the locations of the pulses. By analyzing this system, we prove a criterion for the existence of a countable infinite or finite number of bound states, depending on the strength of the dispersive term in the equation. The theoretical findings are corroborated by computations of the full equation.

Tseluiko, D.; Saprykin, S.; Kalliadasis, S.

2010-03-01

105

Bayesian Semiparametric Structural Equation Models with Latent Variables  

Microsoft Academic Search

Structural equation models (SEMs) with latent variables are widely useful for sparse covariance structure modeling and for\\u000a inferring relationships among latent variables. Bayesian SEMs are appealing in allowing for the incorporation of prior information\\u000a and in providing exact posterior distributions of unknowns, including the latent variables. In this article, we propose a\\u000a broad class of semiparametric Bayesian SEMs, which allow

Mingan Yang; David B. Dunson

2010-01-01

106

Signal processing in the cochlea: The structure equations  

PubMed Central

Background Physical and physiological invariance laws, in particular time invariance and local symmetry, are at the outset of an abstract model. Harmonic analysis and Lie theory are the mathematical prerequisites for its deduction. Results The main result is a linear system of partial differential equations (referred to as the structure equations) that describe the result of signal processing in the cochlea. It is formulated for phase and for the logarithm of the amplitude. The changes of these quantities are the essential physiological observables in the description of signal processing in the auditory pathway. Conclusions The structure equations display in a quantitative way the subtle balance for processing information on the basis of phase versus amplitude. From a mathematical point of view, the linear system of equations is classified as an inhomogeneous - equation. In suitable variables the solutions can be represented as the superposition of a particular solution (determined by the system) and a holomorphic function (determined by the incoming signal). In this way, a global picture of signal processing in the cochlea emerges.

2011-01-01

107

Factor structure and measurement invariance of the cognitive failures questionnaire across the adult life span.  

PubMed

The Cognitive Failures Questionnaire (CFQ) is designed to assess a person's proneness to committing cognitive slips and errors in the completion of everyday tasks. Although the CFQ is a widely used instrument, its factor structure remains an issue of scientific debate. The present study used data of a representative sample (N = 1,303, 24-83 years of age) from the Maastricht Aging Study (MAAS) to test and compare factor solutions for the CFQ previously reported in the literature by means of confirmatory factor analysis of ordered categorical variables. A three-factor model of the CFQ from an exploratory factor analysis was tested for increasing levels of measurement invariance across six age groups. Factor (co-)variances remained stable across the age groups, mean differences were observed for the factor Forgetfulness with higher means for older participants, and the factor Distractibility where participants older than 60 years of age had lower means. PMID:19066391

Rast, Philippe; Zimprich, Daniel; Van Boxtel, Martin; Jolles, Jellemer

2008-12-09

108

Adolescent stress: evaluation of the factor structure of the Adolescent Stress Questionnaire (ASQ-N).  

PubMed

The present study reports an evaluation of the factor structure of the Norwegian version of the Adolescent Stress Questionnaire (ASQ-N) among 723 students. Principal components analysis (PCA) revealed nine internally consistent dimensions of adolescent stress. Scales constructed from this PCA correlated positively with measures of depression and anxiety and negatively with self-esteem. Girls reported higher stress levels than boys in seven of the nine scales and age was also positively correlated with the scale scores of adolescent stress. The results revealed that the instrument has potential for measuring adolescent stress. The stability of the ASQ-N needs to be tested repeatedly, across cohorts and over time, to establish the adequacy for use in Norwegian adolescent studies. PMID:20149144

Moksnes, Unni Karin; Byrne, Don G; Mazanov, Jason; Espnes, Geir Arild

2010-02-08

109

The Weight Influenced Self-Esteem Questionnaire (WISE-Q): factor structure and psychometric properties.  

PubMed

Weight-based self-esteem (WBSE) is hypothesized to be the core cognitive feature of eating disorders. The Weight Influenced Self-Esteem Questionnaire (WISE-Q) was designed to measure the influence of a negatively perceived body image on multiple dimensions of self-esteem, which we believe to be one aspect of WBSE. Study 1 sought to determine the factor structure of the WISE-Q as well as to examine the reliability and concurrent validity of WISE-Q scores among eating disorder and undergraduate student participants. In Study 2, validity was further investigated by examining changes in WISE-Q scores with treatment. The WISE-Q has two factors representing generalized and expected WBSE. Evidence of internal and test-retest reliability was found. Also, the pattern of correlations between WISE-Q scores and other constructs was in line with predictions. As expected, WISE-Q scores improved with treatment yet remained high. PMID:23068567

Trottier, Kathryn; McFarlane, Traci; Olmsted, Marion P; McCabe, Randi E

2012-10-12

110

Research on Perceived Organizational Support for the High-tech Enterprise Knowledge-worker's Loyalty Based on Structure Equation Modeling  

Microsoft Academic Search

Based on the Organizational Support Theory, this paper forms evaluation Index of loyalty model for knowledge-workers of high-tech enterprise in information and communication field through three dimensions-job satisfaction, perceived organizational support, and organizational commitment. By questionnaire conducted in an information communication company, this paper achieves data for structural equation and validates the fit index. Then it confirms the evaluation method

Wang Yan; Cheng Yanxia

2011-01-01

111

Factor structure, reliability, and validity of the Chinese version of the School Bullying Experience Questionnaire.  

PubMed

The aims of this study were to examine the factor structure, internal consistency, 1-month test-retest reliability, and congruent validity of the Chinese version of the School Bullying Experience Questionnaire (C-SBEQ). Study 1, in which 5751 Taiwanese adolescents in Southern Taiwan participated, examined the adequacy of the original four-factor structure of the C-SBEQ using confirmatory factor analysis (CFA) and internal-consistency reliability using Cronbach ?. Study 2, in which 108 adolescents in Southern Taiwan participated, examined the 1-month test-retest reliability using intraclass correlation coefficients (ICCs). We examined the congruent validity of the C-SBEQ by examining the consistency between self-reported and teacher- and classmate-nominated experiences of bullying involvement in Study 2. The results of CFA supported the four-factor structure of the C-SBEQ in Taiwanese adolescents. The test-retest and internal reliability values of all subscales of the C-SBEQ were at acceptable to satisfactory levels. Nominated adolescents had significantly higher self-reported scores on three C-SBEQ subscales than non-nominated ones, and the levels of agreement between self-reported and nominated victims were moderate. The results of this study indicate that the C-SBEQ is appropriate for assessing bullying experiences in Taiwanese adolescents. PMID:22974670

Yen, Cheng-Fang; Kim, Young-Shin; Tang, Tze-Chun; Wu, Yu-Yu; Cheng, Chung-Ping

2012-07-07

112

Maximum likelihood estimation and model comparison of nonlinear structural equation models with continuous and polytomous variables  

Microsoft Academic Search

Recently, it is recognized that nonlinear relationships among latent variables in a structural equation model are important. In this article, maximum likelihood (ML) analysis of a general nonlinear structural equation model that contains fixed covariates in the measurement equation and the nonlinear structural equation is investigated. A MCEM algorithm is implemented to obtain the ML estimates, in which the E-step

Sik-yum Lee; Xin-yuan Song

2003-01-01

113

Neutron Star Structure and the Equation of State  

NASA Astrophysics Data System (ADS)

The structure of neutron stars is considered from theoretical and observational perspectives. We demonstrate an important aspect of neutron star structure: the neutron star radius is primarily determined by the behavior of the pressure of matter in the vicinity of nuclear matter equilibrium density. In the event that extreme softening does not occur at these densities, the radius is virtually independent of the mass and is determined by the magnitude of the pressure. For equations of state with extreme softening or those that are self-bound, the radius is more sensitive to the mass. Our results show that in the absence of extreme softening, a measurement of the radius of a neutron star more accurate than about 1 km will usefully constrain the equation of state. We also show that the pressure near nuclear matter density is primarily a function of the density dependence of the nuclear symmetry energy, while the nuclear incompressibility and skewness parameters play secondary roles. In addition, we show that the moment of inertia and the binding energy of neutron stars, for a large class of equations of state, are nearly universal functions of the star's compactness. These features can be understood by considering two analytic, yet realistic, solutions of Einstein's equations, by, respectively, Buchdahl and Tolman. We deduce useful approximations for the fraction of the moment of inertia residing in the crust, which is a function of the stellar compactness and, in addition, the pressure at the core-crust interface.

Lattimer, J. M.; Prakash, M.

2001-03-01

114

Semiparametric Bayesian analysis of structural equation models with fixed covariates.  

PubMed

Latent variables play the most important role in structural equation modeling. In almost all existing structural equation models (SEMs), it is assumed that the distribution of the latent variables is normal. As this assumption is likely to be violated in many biomedical researches, a semiparametric Bayesian approach for relaxing it is developed in this paper. In the context of SEMs with covariates, we provide a general Bayesian framework in which a semiparametric hierarchical modeling with an approximate truncation Dirichlet process prior distribution is specified for the latent variables. The stick-breaking prior and the blocked Gibbs sampler are used for efficient simulation in the posterior analysis. The developed methodology is applied to a study of kidney disease in diabetes patients. A simulation study is conducted to reveal the empirical performance of the proposed approach. Supplementary electronic material for this paper is available in Wiley InterScience at http://www.mrw.interscience.wiley.com/suppmat/1097-0258/suppmat/. PMID:18008378

Lee, Sik-Yum; Lu, Bin; Song, Xin-Yuan

2008-06-15

115

Poisson structure of the equations of ideal multispecies fluid electrodynamics  

SciTech Connect

The equations of the two- (or multi-) fluid model of plasma physics are recast in Hamiltonian form, following general methods of symplectic geometry. The dynamical variables are the fields of physical interest, but are noncanonical, so that the Poisson bracket in the theory is not the standard one. However, it is a skew-symmetric bilinear form which, from the method of derivation, automatically satisfies the Jacobi identity; therefore, this noncanonical structure has all the essential properties of a canonical Poisson bracket.

Spencer, R.G.

1984-08-01

116

Religion, Forgiveness, Hostility and Health: A Structural Equation Analysis  

Microsoft Academic Search

Religious participation has been shown to increase certain factors thought to be protective of health, including social support\\u000a and positive health habits. The current study considers whether religious participation may likewise have a positive influence\\u000a on health by increasing forgiveness and diminishing hostility. A structural equation analysis of data collected from a national\\u000a survey of 1,629 participants supported the hypothesized

Laura J. Lutjen; Nava R. Silton; Kevin J. Flannelly

117

Einstein metrics, hypercomplex structures and the Toda field equation  

Microsoft Academic Search

We obtain explicitly all solutions of the SU(?) Toda field equation with the property that the associated Einstein–Weyl space admits a 2-sphere of divergence-free shear-free geodesic congruences. The solutions depend on an arbitrary holomorphic function and give rise to new hyperKähler and selfdual Einstein metrics with one-dimensional isometry group. These metrics each admit a compatible hypercomplex structure with respect to which

David M. J. Calderbank; Paul Tod

2001-01-01

118

Information and other criteria in structural equation model selection  

Microsoft Academic Search

This article presents the results of a simulation study evaluating information criteria in conjunction with other well-known criteria for model selection in structural equation modeling (SEM). Two sets of simulation experiments were performed. In both sets, sample sizes of n = 100,400,1000,6000 were used and the performance of 18 criteria was assessed by the frequency with which each of five

Dominique M. A. Haughton; Johan H. L. Oud; Robert A. R. G. Jansen

1997-01-01

119

People Are Variables Too: Multilevel Structural Equations Modeling  

Microsoft Academic Search

The article uses confirmatory factor analysis (CFA) as a template to explain didactically multilevel structural equation models (ML-SEM) and to demonstrate the equivalence of general mixed-effects models and ML-SEM. An intuitively appealing graphical representation of complex ML-SEMs is introduced that succinctly describes the underlying model and its assumptions. The use of definition variables (i.e., observed variables used to fix model

Paras D. Mehta; Michael C. Neale

2005-01-01

120

On Bayesian structural inference in a simultaneous equation model  

Microsoft Academic Search

Econometric issues that are considered fundamental in the development of Bayesian structural\\u000ainference within a Simultaneous Equation Model are surveyed. The difficulty of specifying \\u000aprior information which is of interest to economists and which yields tractable posterior \\u000aand predictive distributions has started this line of research. A major issue is the \\u000anonstandard shape of the likelihood due to reduced rank

Dijk van H. K

2002-01-01

121

Structure of Neutron Stars with Unified Equations of State  

NASA Astrophysics Data System (ADS)

We present a set of three unified equations of states (EoSs) based on the nuclear energy-density functional (EDF) theory. These EoSs are based on generalized Skyrme forces fitted to essentially all experimental atomic mass data and constrained to reproduce various properties of infinite nuclear matter as obtained from many-body calculations using realistic two- and three-body interactions. The structure of cold isolated neutron stars is discussed in connection with some astrophysical observations.

Fantina, A. F.; Chamel, N.; Pearson, J. M.; Goriety, S.

2012-12-01

122

Factor Structure of the Alcohol Urge Questionnaire Under Neutral Conditions and During a Cue-elicited Urge State  

Microsoft Academic Search

Background: The Alcohol Urge Questionnaire (AUQ) is a promising multi-item measure of self- reported urges to drink in human laboratory studies; however, its factor structure has not been examined during an acute urge state. This study sought to validate the AUQ's factor structure under neutral conditions and during a cue-elicited urge state in heavy drinkers. Methods: Participants (248 heavy drinkers;

James MacKillop

2006-01-01

123

Dysfunctional Cognitions in Personality Pathology: The Structure and Validity of the Personality Belief Questionnaire  

PubMed Central

Background This study examines the structure of the Personality Belief Questionnaire (PBQ), a self-report instrument designed to assess dysfunctional beliefs associated with personality pathology, as proposed by the cognitive theory of personality dysfunction. Methods The PBQ was examined using exploratory factor analysis with responses from 438 depressed outpatients, and confirmatory factor analysis with responses from 683 treatment-seeking psychiatric outpatients. All participants were assessed for personality disorder using a standard clinical interview. The validity of the resulting factor structure was assessed in the combined sample (N=1121) by examining PBQ scores for patients with and without personality disorder diagnoses. Results Exploratory and confirmatory analyses converged to indicate that the PBQ is best described by 7 empirically identified factors: 6 assess dysfunctional beliefs associated with forms of personality pathology recognized in DSM-IV. Validity analyses revealed that those diagnosed with a personality disorder evidenced a higher average score on all factors, relative to those without these disorders. Subsets of patients diagnosed with specific DSM-IV personality disorders scored higher, on average, on the factor associated with their respective diagnosis, relative to all other factors. Conclusions The pattern of results has implications for the conceptualization of personality pathology. To our knowledge, no formal diagnostic or assessment system has yet systematically incorporated the role of dysfunctional beliefs into its description of personality pathology. The identification of dysfunctional beliefs may not only aid in case conceptualization, but may provide unique targets for psychological treatment. Recommendations for future personality pathology assessment systems are provided.

Fournier, Jay C.; DeRubeis, Robert J.; Beck, Aaron T.

2013-01-01

124

Parental feeding styles and adolescents’ healthy eating habits. Structure and correlates of a Costa Rican questionnaire  

Microsoft Academic Search

This study designed and validated a questionnaire aimed at examining parental feeding styles to encourage healthy eating habits among Costa Rican adolescents. Adolescents (n=133; mean age 15.4 years), and their parents, participated in the study. The parents completed a parental feeding style questionnaire, and the adolescents completed 3-day food records. Confirmatory factor analyses suggest four distinct parental feeding styles, (a)

Rafael Monge-Rojas; Vanesa Smith-Castro; Uriyoán Colon-Ramos; Carlos Garita-Arce; Marta Sánchez-López; Anne Chinnock

2010-01-01

125

Evaluation of the Alcohol Craving Questionnaire-Now factor structures: Application of a cue reactivity paradigm  

PubMed Central

The current study compared the psychometric properties and clinical/research utility of four distinct factor/subscale models of alcohol craving (three factor-derived models, and one rationally-derived model) as measured by the Alcohol Craving Questionnaire-Now in social (n = 52) and alcohol dependent (n = 71) drinkers. All participants completed a self-report measure of alcohol abuse in addition to engaging in a structured interview and cue reactivity protocol. Participants provided self-reported craving, as well as desire to approach or avoid drinking, during a cue exposure task using separate analogue scales. Factor/subscale models were compared in terms of internal consistency, convergent and divergent validity, and ability to predict cue-elicited approach and craving in addition to diagnostic status. All models demonstrated high levels of internal consistency, convergent and divergent validity, and the ability to predict both cue-elicited craving and alcohol dependence status. Specific strengths and weaknesses of each model are examined and the theoretical, clinical, and research utility of the current findings are discussed.

Connolly, Kevin M.; Coffey, Scott F.; Baschnagel, Joseph S.; Drobes, David J.; Saladin, Michael E.

2009-01-01

126

A bayesian modeling approach for generalized semiparametric structural equation models.  

PubMed

In behavioral, biomedical, and psychological studies, structural equation models (SEMs) have been widely used for assessing relationships between latent variables. Regression-type structural models based on parametric functions are often used for such purposes. In many applications, however, parametric SEMs are not adequate to capture subtle patterns in the functions over the entire range of the predictor variable. A different but equally important limitation of traditional parametric SEMs is that they are not designed to handle mixed data types-continuous, count, ordered, and unordered categorical. This paper develops a generalized semiparametric SEM that is able to handle mixed data types and to simultaneously model different functional relationships among latent variables. A structural equation of the proposed SEM is formulated using a series of unspecified smooth functions. The Bayesian P-splines approach and Markov chain Monte Carlo methods are developed to estimate the smooth functions and the unknown parameters. Moreover, we examine the relative benefits of semiparametric modeling over parametric modeling using a Bayesian model-comparison statistic, called the complete deviance information criterion (DIC). The performance of the developed methodology is evaluated using a simulation study. To illustrate the method, we used a data set derived from the National Longitudinal Survey of Youth. PMID:24092481

Song, Xin-Yuan; Lu, Zhao-Hua; Cai, Jing-Heng; Ip, Edward Hak-Sing

2013-02-01

127

Religion, forgiveness, hostility and health: a structural equation analysis.  

PubMed

Religious participation has been shown to increase certain factors thought to be protective of health, including social support and positive health habits. The current study considers whether religious participation may likewise have a positive influence on health by increasing forgiveness and diminishing hostility. A structural equation analysis of data collected from a national survey of 1,629 participants supported the hypothesized model that (a) religiosity is related to greater forgiveness, (b) greater forgiveness, in turn, is related to reduced hostility and finally, (c) reduced hostility is related to better subjective health. PMID:21691897

Lutjen, Laura J; Silton, Nava R; Flannelly, Kevin J

2012-06-01

128

Structural Stability for Fractional Differential Equations as Boundary Value Problems  

NASA Astrophysics Data System (ADS)

In this paper we aim to construct reliable numerical schemes for the approximation of solutions to fractional boundary value problems. We focus on equations of the form D*?y(t) = f(t,y(t)), y(a) = y1, where D*? denotes the fractional derivative of Caputo type, the order ? satisfies 0 < ? < 1 and f is a suitably behaved function. We seek solutions over a finite interval [0,T] and 0 < a < T. We investigate the structural stability of the underlying problem and discuss the numerical stability of the numerical methods we construct.

Ford, Neville J.; Morgado, M. L.

2010-09-01

129

A semiparametric Bayesian approach for structural equation models.  

PubMed

In the development of structural equation models (SEMs), observed variables are usually assumed to be normally distributed. However, this assumption is likely to be violated in many practical researches. As the non-normality of observed variables in an SEM can be obtained from either non-normal latent variables or non-normal residuals or both, semiparametric modeling with unknown distribution of latent variables or unknown distribution of residuals is needed. In this article, we find that an SEM becomes nonidentifiable when both the latent variable distribution and the residual distribution are unknown. Hence, it is impossible to estimate reliably both the latent variable distribution and the residual distribution without parametric assumptions on one or the other. We also find that the residuals in the measurement equation are more sensitive to the normality assumption than the latent variables, and the negative impact on the estimation of parameters and distributions due to the non-normality of residuals is more serious. Therefore, when there is no prior knowledge about parametric distributions for either the latent variables or the residuals, we recommend making parametric assumption on latent variables, and modeling residuals nonparametrically. We propose a semiparametric Bayesian approach using the truncated Dirichlet process with a stick breaking prior to tackle the non-normality of residuals in the measurement equation. Simulation studies and a real data analysis demonstrate our findings, and reveal the empirical performance of the proposed methodology. A free WinBUGS code to perform the analysis is available in Supporting Information. PMID:20533410

Song, Xin-Yuan; Pan, Jun-Hao; Kwok, Timothy; Vandenput, Liesbeth; Ohlsson, Claes; Leung, Ping-Chung

2010-06-01

130

Fermionic covariant prolongation structure theory for multidimensional super nonlinear evolution equation  

NASA Astrophysics Data System (ADS)

The fermionic covariant prolongation structure theory is investigated. We extend the fermionic covariant prolongation structure technique to the multidimensional super nonlinear evolution equation and present the fermionic covariant fundamental equations determining the prolongation structure. Furthermore, we investigate a (2+1)-dimensional super nonlinear Schrödinger equation and analyze its integrability by means of this prolongation structure technique. We derive its Lax representation and Bäcklund transformation. Moreover, we present a solution of this multidimensional super integrable equation.

Yan, Zhao-Wen; Li, Min-Li; Wu, Ke; Zhao, Wei-Zhong

2013-03-01

131

Factor Structure of the World Health Organization's Quality of Life Questionnaire-BREF in Patients with Coronary Artery Disease  

PubMed Central

Background: The World Health Organization Quality of Life Questionnaire (WHOQOL)-BREF is one of the most known general questionnaires for assessment of quality of life (QOL) in both healthy populations and in various diseases subgroups. The aim of the present study was to examine the construct validity of this questionnaire in patients with coronary artery disease (CAD) using factor analysis. Methods: Two hundred and seventy-five patients aged 35-80 years old with the diagnosis of CAD admitted to the Tehran Heart Center operating room for coronary artery bypass were consecutively entered into the study. QOL was assessed using the WHOQOL-BREF. To estimate the reliability of the QOL questionnaire, Cronbach's a coefficient was measured. To assess the structure of the questionnaire, we firstly performed confirmatory factor analysis to test the hypothesized factor models. Exploratory factor analysis was then performed using the principal component method with varimax rotation. Results: Reliability of the questionnaire was low (Cronbach's a for different domains ranged from 0.24 to 0.74). In confirmatory factor analysis, only the 1-factor model indicated a good fit to the data. The exploratory factor analysis indicated a five-factor solution that jointly accounted for 55.7% of the variance observed. Also, the pattern of item loading was very different from the original structure of the questionnaire. Conclusions: The findings suggest that the WHOQOL-BREF might only be a measure of the overall QOL in patients with CAD, and is not a suitable instrument for measuring the different QOL dimensions as expected in this population.

Najafi, Mahdi; Sheikhvatan, Mehrdad; Montazeri, Ali; Sheikhfatollahi, Mahmood

2013-01-01

132

Psychotropic substance abuse among adolescents: a structural equation model on risk and protective factors.  

PubMed

The use of psychotropic substances in adolescents represents a serious public health problem. In this study a representative sample of 485 Austrian students between 14 and 18 years of age were investigated with a semistructured interview about substance-related issues and completed the general health questionnaire. The following rates of regular psychotropic substance use were found: cigarettes 41.4%, alcohol 44.5%, cannabis 10.1%, and other illicit substances 3%. Logistic regression analyses and structural equation modeling revealed the following major risk factors for substance use: peer pressure, negative family atmosphere, school difficulties, and psychopathology. Knowledge about substance use acted as a protective factor. Prevention of adolescent substance use and misuse should aim at these different targets. Information about coping with peer pressure may be a particularly promising route of intervention. PMID:16798682

Rumpold, Gerhard; Klingseis, Michael; Dornauer, Kurt; Kopp, Martin; Doering, Stephan; Höfer, Stefan; Mumelter, Birgit; Schüssler, Gerhard

2006-01-01

133

Factor Structure and Psychometric Properties of the Children's Negative Cognitive Error Questionnaire with a Clinically Depressed Adolescent Sample  

Microsoft Academic Search

The factor structure and psychometric properties of the Children's Negative Cognitive Error Questionnaire (CNCEQ) were examined with 427 adolescents ages 12 to 18 (193 boys) with current major depressive disorder. Results of confirmatory factor analysis supported a four-factor model comprised of three content area factors (i.e., social, academic, athletic) and a general factor. Internal consistencies ranged between .84 and .94

Julie Newman Kingery; Hayden O. Kepley; Golda S. Ginsburg; John T. Walkup; Susan G. Silva; Rick H. Hoyle; Mark A. Reinecke; John S. March

2009-01-01

134

The Prospective and Retrospective Memory Questionnaire (PRMQ): Latent structure, normative data and discrepancy analysis for proxy-ratings  

Microsoft Academic Search

Objectives. To evaluate the proxy-rating version of the Prospective and Retrospective Memory Questionnaire (PRMQ) and provide norms and methods for score interpretation. Design. Cross-sectional and correlational. Methods. The PRMQ was administered to a large sample drawn from the general adult population (N ¼ 570). Confirmatory factor analysis (CFA) was used to test competing models of its latent structure. Various psychometric

John R. Crawford; Julie D. Henry; Aileen L. Ward; John Blake

2006-01-01

135

Factor Structure and Psychometric Properties of the Children's Negative Cognitive Error Questionnaire with a Clinically Depressed Adolescent Sample  

ERIC Educational Resources Information Center

The factor structure and psychometric properties of the Children's Negative Cognitive Error Questionnaire (CNCEQ) were examined with 427 adolescents ages 12 to 18 (193 boys) with current major depressive disorder. Results of confirmatory factor analysis supported a four-factor model comprised of three content area factors (i.e., social, academic,…

Kingery, Julie Newman; Kepley, Hayden O.; Ginsburg, Golda S.; Walkup, John T.; Silva, Susan G.; Hoyle, Rick H.; Reinecke, Mark A.; March, John S.

2009-01-01

136

Validating the Children's Behavior Questionnaire in Dutch Children: Psychometric Properties and a Cross-Cultural Comparison of Factor Structures  

Microsoft Academic Search

In this article, we examined the factorial validity of the Dutch translation of the Children's Behavior Questionnaire (CBQ) and the Very Short Form scores. In addition, we conducted cross-cultural comparisons of temperament structure. In total, 353 parents of 6- to 8-year-olds completed the instrument. The original higher order factor structure of the different CBQ forms was generally replicated and represented

Ester F. C. Sleddens; Stef P. J. Kremers; Math J. J. M. Candel; Nanne N. K. De Vries; Carel Thijs

2011-01-01

137

A New Look at the Big Five Factor Structure through Exploratory Structural Equation Modeling  

ERIC Educational Resources Information Center

NEO instruments are widely used to assess Big Five personality factors, but confirmatory factor analyses (CFAs) conducted at the item level do not support their a priori structure due, in part, to the overly restrictive CFA assumptions. We demonstrate that exploratory structural equation modeling (ESEM), an integration of CFA and exploratory…

Marsh, Herbert W.; Ludtke, Oliver; Muthen, Bengt; Asparouhov, Tihomir; Morin, Alexandre J. S.; Trautwein, Ulrich; Nagengast, Benjamin

2010-01-01

138

A Double-Structure Structural Equation Model for Three-Mode Data  

ERIC Educational Resources Information Center

Structural equation models are commonly used to analyze 2-mode data sets, in which a set of objects is measured on a set of variables. The underlying structure within the object mode is evaluated using latent variables, which are measured by indicators coming from the variable mode. Additionally, when the objects are measured under different…

Gonzalez, Jorge; De Boeck, Paul; Tuerlinckx, Francis

2008-01-01

139

A Double-Structure Structural Equation Model for Three-Mode Data  

ERIC Educational Resources Information Center

|Structural equation models are commonly used to analyze 2-mode data sets, in which a set of objects is measured on a set of variables. The underlying structure within the object mode is evaluated using latent variables, which are measured by indicators coming from the variable mode. Additionally, when the objects are measured under different…

Gonzalez, Jorge; De Boeck, Paul; Tuerlinckx, Francis

2008-01-01

140

Coagulation-diffusion systems: Derivation and existence of solutions for the diffuse interface structure equations  

Microsoft Academic Search

This paper considers an infinite system of partial differential equations, the coagulation-diffusion equations, which add spatial diffusion to the classical coagulation equations. The main emphasis is placed on deriving an infinite system of ordinary differential equations which described the structured interface between reacting coagulation and dilute concentration. Existence of solutions to interfacial equaitons is proven under spatial boundary conditions. Sponsored

M. Slemrod

1990-01-01

141

Measuring physical activity among pregnant women using a structured one-week recall questionnaire: evidence for validity and reliability  

PubMed Central

Background Accurate measurement of the components of physical activity during pregnancy can aid in our understanding of the dose response relationships between physical activity and corresponding perinatal outcomes. The aim of this study was to develop and evaluate a one-week recall questionnaire to assess moderate to vigorous physical activity during pregnancy. Methods To assess concurrent-related validity, 177 pregnant women (median 18 weeks' gestation, interquartile range (IQR) 15 -23) kept a structured diary and wore an accelerometer (Actigraph) for one week. At the conclusion of the week, they completed the Pregnancy Infection and Nutrition 3 (PIN3) physical activity questionnaire over the telephone. To assess evidence for test-retest reliability, 109 pregnant women (median 19 weeks' gestation, IQR 18-27) completed the questionnaire twice over the telephone, within 48 hours apart, recalling the same two time periods. Spearman correlation coefficients (SCC) and intraclass correlation coefficients (ICC) were used to assess evidence for validity and reliability, respectively. Results Comparison of the questionnaire to the structured diary was moderate to substantial (SCC 0.47 to 0.69) for several measures of moderate or vigorous physical activity using either perceived or absolute intensity. Comparison of moderate to vigorous physical activity from the questionnaire (absolute intensity using MET-hours/week) to the accelerometer ranged from 0.12 to 0.23 using SCC for absolute intensity (MET-hours/week) and 0.28 to 0.34 using relative intensity (hours/week) (n = 177). Test-retest reliability was moderate to almost perfect for moderate to vigorous physical activity, with the ICC ranging from 0.56 to 0.82 for both perceived and absolute intensities. Conclusions The PIN3 one-week recall questionnaire assessed moderate to vigorous physical activity in the past week with evidence for reliability and validity.

2010-01-01

142

Saudi mothers' preferences about breaking bad news concerning newborns: a structured verbal questionnaire  

PubMed Central

Background Breaking bad news (BBN) to parents whose newborn has a major disease is an ethical dilemma. In Saudi Arabia, BBN about newborns is performed according to the parental preferences that have been reported from non-Arabic/non-Islamic countries. Saudi mothers' preferences about BBN have not yet been studied. Therefore, we aimed to elicit the preferences of Saudi mothers about BBN concerning newborns. Methods We selected a convenience sample of 402 Saudi mothers, aged 18-50 years, who had no previous experience with BBN. We selected them via a simple number-randomization scheme from the premises of a level III Saudi hospital between October of 2009 and January of 2011. We used a hypothetical situation (BBN about trisomy 21) to elicit their preferences about BBN concerning newborns via a structured verbal questionnaire composed of 12 multiple-choice questions. We expressed their preferences as percentages (95% confidence interval), and we used the Kendall's W test (W) to assess the degree of agreement in preferences. Results The Saudi mothers preferred that BBN be conducted with both parents together (64% [60-69]), albeit with weak levels of agreement (W = 0.29). They showed moderate agreement in their preferences that BBN should be conducted early (79% [75-83], W = 0.48), in detail (81% [77-85], W = 0.52), in person (88% [85-91], W = 0.58), and in a quiet setting (86% [83-90], W = 0.53). With extremely weak agreement, they preferred to have a known person present for support during BBN (56% [51-61], W = 0.01), to have close bodily contact with their babies (66% [61-70], W = 0.10), and to have no another patients present (64% [59-68], W = 0.08). They showed moderate levels of agreement in their desires to detail, in advance, their preferences about process of BBN by giving a reversible, written informed consent that could be utilized for guidance, if needed (80% [76-84], W = 0.36). Conclusions In our experience, Saudi mothers' preferences about BBN concerning newborns are varied, suggesting that a "one-size-fits-all" approach is inappropriate. A reversible, written informed consent detailing their preferences about BBN that would be kept in their medical records and utilized for guidance, if needed, may be the best solution, given this level of diversity. These findings merit further study.

2011-01-01

143

Factor Structure of the Early Adolescent Temperament Questionnaire and Measurement Invariance across Gender.  

ERIC Educational Resources Information Center

|Applied confirmatory factor analysis in a test of alternative factor models and measurement invariance across gender groups, using data from the Early Adolescent Temperament Questionnaire focusing on shyness, high-intensity pleasure, activity level, attention, irritability, and fear. Found that factor models based on composite indicators showed…

Kim, Sooyeon; Brody, Gene H.; Murry, Velma McBride

2003-01-01

144

The Home Situations Questionnaire-PDD Version: Factor Structure and Psychometric Properties  

ERIC Educational Resources Information Center

Background: The Home Situations Questionnaire (HSQ) is a caregiver-rated scale designed to assess behavioural non-compliance in everyday settings that has been used in several studies in typically developing children. Currently there is no accepted measure of behavioural non-compliance in children with pervasive developmental disorders (PDDs).…

Chowdhury, M.; Aman, M. G.; Scahill, L.; Swiezy, N.; Arnold, L. E.; Lecavalier, L.; Johnson, C.; Handen, B.; Stigler, K.; Bearss, K.; Sukhodolsky, D.; McDougle, C. J.

2010-01-01

145

Finite-Mixture Structural Equation Models for Response-Based Segmentation and Unobserved Heterogeneity  

Microsoft Academic Search

Two endemic problems face researchers in the social sciences (e.g., Marketing, Economics, Psychology, and Finance): unobserved heterogeneity and measurement error in data. Structural equation modeling is a powerful tool for dealing with these difficulties using a simultaneous equation framework with unobserved constructs and manifest indicators which are error-prone. When estimating structural equation models, however, researchers frequently treat the data as

Kamel Jedidi; Harsharanjeet S. Jagpal; Wayne S. DeSarbo

1997-01-01

146

Structural equation modeling of repeated retrospective reports of childhood maltreatment.  

PubMed

The present study examined errors of reporting, including unreliability and recall bias, in retrospective reports of childhood maltreatment. Data were gathered on retrospective reports of childhood sexual and physical abuse and current mental health in a birth cohort of over 980 participants studied at ages 18 and 21. A structural equation model was developed to estimate the contributions of test unreliability and recall bias to reporting variation. Retrospective abuse reports were of modest test-retest reliability (r(tt) ?=?0.50 approximately). Recall bias accounted for <1% of report variance. As a consequence the observed correlations between maltreatment and mental health closely approximated the corresponding estimated true correlations. The results of the study suggested that, for this cohort, errors of measurement in reports of childhood maltreatment did not pose a significant threat to study validity. PMID:21495111

Fergusson, David M; Horwood, L John; Boden, Joseph M

2011-06-01

147

Modeling Dynamic Functional Neuroimaging Data Using Structural Equation Modeling.  

PubMed

The aims of this study were to present a method for developing a path analytic network model using data acquired from positron emission tomography. Regions of interest within the human brain were identified through quantitative activation likelihood estimation meta-analysis. Using this information, a "true" or population path model was then developed using Bayesian structural equation modeling. To evaluate the impact of sample size on parameter estimation bias, proportion of parameter replication coverage, and statistical power, a 2 group (clinical/control) × 6 (sample size: N = 10, N = 15, N = 20, N = 25, N = 50, N = 100) Markov chain Monte Carlo study was conducted. Results indicate that using a sample size of less than N = 15 per group will produce parameter estimates exhibiting bias greater than 5% and statistical power below .80. PMID:20502535

Price, Larry R; Laird, Angela R; Fox, Peter T; Ingham, Roger J

2009-01-01

148

Hopes and cautions in implementing Bayesian structural equation modeling.  

PubMed

Muthén and Asparouhov (2012) have proposed and demonstrated an approach to model specification and estimation in structural equation modeling (SEM) using Bayesian methods. Their contribution builds on previous work in this area by (a) focusing on the translation of conventional SEM models into a Bayesian framework wherein parameters fixed at zero in a conventional model can be respecified using small-variance priors and (b) implementing their approach in software that is widely accessible. We recognize potential benefits for applied researchers as discussed by Muthén and Asparouhov, and we also see a tradeoff in that effective use of the proposed approach introduces increased demands in terms of expertise of users to navigate new complexities in model specification, parameter estimation, and evaluation of results. We also raise cautions regarding the issues of model modification and model fit. Although we see significant potential value in the use of Bayesian SEM, we also believe that effective use will require an awareness of these complexities. PMID:22962888

MacCallum, Robert C; Edwards, Michael C; Cai, Li

2012-09-01

149

Structural equation modeling in medical research: a primer  

PubMed Central

Background Structural equation modeling (SEM) is a set of statistical techniques used to measure and analyze the relationships of observed and latent variables. Similar but more powerful than regression analyses, it examines linear causal relationships among variables, while simultaneously accounting for measurement error. The purpose of the present paper is to explicate SEM to medical and health sciences researchers and exemplify their application. Findings To facilitate its use we provide a series of steps for applying SEM to research problems. We then present three examples of how SEM has been utilized in medical and health sciences research. Conclusion When many considerations are given to research planning, SEM can provide a new perspective on analyzing data and potential for advancing research in medical and health sciences.

2010-01-01

150

Integral equation theory for the structure of DNA solutions  

NASA Astrophysics Data System (ADS)

The static structure of solutions of DNA fragments is investigated using integral equation theory. The solution is modeled as a four-component system with DNA molecules, bound counterions, free counterions, and coions, all of which are treated explicitly. Each DNA fragment is modeled as a shish-kebab chain with three kinds of sites, i.e., charged sites, neutralized (protonated) sites, and sites with bound counterions. The partial structure factors are obtained using a generalization of the polymer reference interaction model. The undetermined parameters in the model, namely the fraction of protonated and bound sites, are obtained by fitting theoretical predictions for the polymer-polymer and polymer-counterions structure factors to experimental data. It is found that a large majority of counterions is localized near the DNA molecules due to counterions binding and protonation. The bound counterions make a dominant contribution to the total scattering from counterion species. The best fit is obtained when each DNA molecule contains about 22% protonated sites and 53% counterion occupied sites, i.e., the effective DNA charge fraction is about 0.25. This DNA charge fraction is consistent with electrospray ionization and DNA titration experiments.

Shew, Chwen-Yang; Yethiraj, Arun

2002-03-01

151

Elasto-Visco-Plastic Constitutive Equations for Quasi-Static Structures Calculations.  

National Technical Information Service (NTIS)

The development of elasto-visco-plastic constitutive equations for quasi-static structures calculations is discussed. The equations are verified for the stable materials used in mechanical construction and are extended to conditions of varying temperature...

J. Lemaitre

1972-01-01

152

Measurement structure of the Pain Self-Efficacy Questionnaire in a sample of Chinese patients with chronic pain  

Microsoft Academic Search

Objective: To examine the factorial structure of the Chinese translation of the Pain Self-Efficacy Questionnaire in a sample of Chinese patients with chronic pain.Setting: Outpatient physiotherapy department in a local hospital and a local rehabilitation clinic.Participants: One hundred and twenty patients with chronic pain in physiotherapy treatment.Methods: Each participant was asked to complete the Chinese version of the Pain Self-Efficacy

Sinfia KS Vong; Gladys LY Cheing; Chetwyn CH Chan; Fong Chan; Arran SL Leung

2009-01-01

153

Factor Structure of the Reasons for Attempting Suicide Questionnaire (RASQ) with Suicide Attempters  

Microsoft Academic Search

A sample of 134 suicide attempters completed the Reasons for Attempting Suicide Questionnaire (RASQ). Maximum likelihood factor and principal components analyses confirmed the multidimensionality of the RASQ, with two-component and three-factor models each receiving support. Scales from these competing multidimensional RASQ models demonstrated adequate internal consistency reliability. For the two-component model, two previously developed scales demonstrated differential validity with suicide

Ronald R. Holden; Michelle M. DeLisle

2006-01-01

154

The structure of the perceived sociocultural influences on body image and body change questionnaire  

Microsoft Academic Search

This article is concerned with the development and evaluation of the Perceived Sociocultural Influences on Body Image and\\u000a Body Change Questionnaire. The scale was designed to assess the perceived nature of feedback received from mother, father,\\u000a best male friend, and best female friend togain weight, lose weight, and increase muscle tone. The perceived feedback from\\u000a the media on each of

Marita P. McCabe; Lina A. Ricciardelli

2001-01-01

155

The Offer Self-Image Questionnaire for adolescents: Psychometric properties and factor structure  

Microsoft Academic Search

The reliability and validity of the Offer Self-Image Questionnaire (OSIQ) for adolescents were investigated using data from an Australian sample of male and female school students, with an average age of 14.9 years (n=216). Reliability coefficients were high for all subscales except the Morals subscale. Results indicated significant correlations of the OSIQ subscales with Lang and Tisher's Children's Depression Scale

Wendy Patton; Patricia Noller

1994-01-01

156

Equation of State of Structured Matter at Finite Temperature  

NASA Astrophysics Data System (ADS)

We investigate the properties of nuclear matter at the first-order phase transitions such as liquid-gas phase transition and hadron-quark phase transition. As a general feature of the first-order phase transitions of matter consisting of many species of charged particles, there appears a mixed phases with geometrical structures called ``pasta'' due to the balance of the Coulomb repulsion and the surface tension between two phases [G.~D.~Ravenhall, C.~J.~Pethick and J.~R.~Wilson, Phys. Rev. Lett. 50 (1983), 2066. M.~Hashimoto, H.~Seki and M.~Yamada, Prog. Theor. Phys. 71 (1984), 320.] The equation of state (EOS) of mixed phase is different from the one obtained by a bulk application of the Gibbs conditions or by the Maxwell construction due to the effects of the non-uniform structure. We show that the charge screening and strong surface tension make the EOS close to that of the Maxwell construction. The thermal effects are elucidated as well as the above finite-size effects.

Maruyama, T.; Yasutake, N.; Tatsumi, T.

157

A Bayesian Approach for Analyzing Hierarchical Data With Missing Outcomes Through Structural Equation Models  

Microsoft Academic Search

Structural equation models are widely appreciated in behavioral, social, and psychological research to model relations between latent constructs and manifest variables, and to control for measurement errors. Most applications of structural equation models are based on fully observed data that are independently distributed. However, hierarchical data with a correlated structure are common in behavioral research, and very often, missing data

Xin-Yuan Song; Sik-Yum Lee

2008-01-01

158

Examining the Structural Validity of the Strengths and Difficulties Questionnaire (SDQ) in a U.S. Sample of Custodial Grandmothers  

PubMed Central

The authors examined the structural validity of the parent informant version of the Strengths and Difficulties Questionnaire (SDQ) with a sample of 733 custodial grandparents. Three models of the SDQ’s factor structure were evaluated with confirmatory factor analysis based on the item covariance matrix. Although indices of fit were good across all 3 models, a model that included a newly hypothesized positive construal method factor in addition to the 4 symptom factors (Emotional Symptoms, Conduct Problems, Hyperactivity-Inattention, Peer Problems) and the single Prosocial Behavior factor originally intended for the SDQ provided the best representation of this instrument’s latent structure. Structural validity was further evidenced by measurement invariance across grandparent race and grandchild gender and age, a conceptually meaningful pattern of cross-scale correlations, and the acceptable internal reliability estimates found for each subscale. Measurement and clinical implications of the results are discussed.

Palmieri, Patrick A.; Smith, Gregory C.

2007-01-01

159

Ballistic limit equation for equipment placed behind satellite structure walls  

Microsoft Academic Search

A new ballistic limit equation has been developed for the case of a Whipple shield configuration or a sandwich panel with honeycomb core placed in front of a backwall. This “triple plate” ballistic limit equation considers explicitly the thicknesses, materials and spacings of each of the three plates. The third plate, i.e., the backwall, represents the cover plate or external

F. K. Schäfer; S. Ryan; M. Lambert; R. Putzar

2008-01-01

160

THE STRUCTURE OF CONSCIENTIOUSNESS: AN EMPIRICAL INVESTIGATION BASED ON SEVEN MAJOR PERSONALITY QUESTIONNAIRES  

Microsoft Academic Search

The purpose of this study was to identify the underlying structure of the trait domain of Conscientiousness using scales drawn from 7 major personality inventories. Thirty-six scales conceptually related to Consci- entiousness were administered to a large community sample (N = 737); analyses of those scales revealed a hierarchical structure with 6 factors: industriousness, order, self-control, responsibility, traditionalism, and virtue.

BRENT W. ROBERTS; OLEKSANDR S. CHERNYSHENKO; STEPHEN STARK; LEWIS R. GOLDBERG

2005-01-01

161

A First Look at the Structured Clinical Interview for "DSM-IV" Personality Disorders Screening Questionnaire: More Than Just a Screener?  

ERIC Educational Resources Information Center

This study examined the psychometrics of the Structured Clinical Interview for DSM-IV Personality Disorders Personality Questionnaire (SCID-IIP) self-report personality questionnaire. The responses to the instrument were found reliable and evidenced good self-other convergence. Correlations with external criteria showed the SCID-IIP to contain…

Piedmont, Ralph L.; Sherman, Martin F.; Sherman, Nancy C.; Williams, Joseph E. G.

2003-01-01

162

On the Lagrangian Structure of Integrable Quad-Equations  

Microsoft Academic Search

The new idea of flip invariance of action functionals in multidimensional lattices was recently highlighted as a key feature\\u000a of discrete integrable systems. Flip invariance was proved for several particular cases of integrable quad-equations by Bazhanov,\\u000a Mangazeev and Sergeev and by Lobb and Nijhoff. We provide a simple and case-independent proof for all integrable quad-equations.\\u000a Moreover, we find a new

Alexander I. Bobenko; Yuri B. Suris

2010-01-01

163

Electromagnetic scattering of large structures in layered earths using integral equations  

Microsoft Academic Search

An electromagnetic scattering algorithm for large conductivity structures in stratified media has been developed and is based on the method of system iteration and spatial symmetry reduction using volume electric integral equations. The method of system iteration divides a structure into many substructures and solves the resulting matrix equation using a block iterative method. The block submatrices usually need to

Zonghou Xiong; Alan C. Tripp

1995-01-01

164

Evaluation of Structural Equation Mixture Models: Parameter Estimates and Correct Class Assignment  

ERIC Educational Resources Information Center

Structural equation mixture models (SEMMs) are latent class models that permit the estimation of a structural equation model within each class. Fitting SEMMs is illustrated using data from 1 wave of the Notre Dame Longitudinal Study of Aging. Based on the model used in the illustration, SEMM parameter estimation and correct class assignment are…

Tueller, Stephen; Lubke, Gitta

2010-01-01

165

Applications of structural equation modeling in marketing and consumer research: A review  

Microsoft Academic Search

This paper reviews prior applications of structural equation modeling in four major marketing journals (the Journal of Marketing, Journal of Marketing Research, International Journal of Research in Marketing, and the Journal of Consumer Research) between 1977 and 1994. After documenting and characterizing the number of applications over time, we discuss important methodological issues related to structural equation modeling and assess

Hans Baumgartner; Christian Homburg

1996-01-01

166

On the Likelihood Ratio Test in Structural Equation Modeling When Parameters Are Subject to Boundary Constraints  

Microsoft Academic Search

The authors show how the use of inequality constraints on parameters in structural equation models may affect the distribution of the likelihood ratio test. Inequality constraints are implicitly used in the testing of commonly applied structural equation models, such as the common factor model, the autoregressive model, and the latent growth curve model, although this is not commonly acknowledged. Such

Reinoud D. Stoel; Francisca Galindo Garre; Conor Dolan; Godfried van den Wittenboer

2006-01-01

167

A Hierarchical Bayesian Methodology for Treating Heterogeneity in Structural Equation Models  

Microsoft Academic Search

Structural equation models are widely used in marketing and psychometric literature to model relationships between unobserved constructs and manifest variables and to control for measurement error. Most applications of structural equation models assume that data come from a homogeneous population. This assumption may be unrealistic, as individuals are likely to be heterogeneous in their perceptions and evaluations of unobserved constructs.

Asim Ansari; Kamel Jedidi; Sharan Jagpal

2000-01-01

168

Bayesian nonlinear structural equation modeling for hierarchical validation of dynamical systems  

Microsoft Academic Search

This paper presents a new Bayesian nonlinear structural equation modeling approach to hierarchical model assessment of dynamic systems, considering uncertainty in both predicted and measured time series data. A generalized structural equation modeling with nonlinear latent variables is presented to model two sets of relationships in multivariate hierarchical model assessment, namely, the computational model to system-level data, and low-level data

Xiaomo Jiang; Sankaran Mahadevan; Angel Urbina

2010-01-01

169

[Antecedents and consequences of workplace bullying: a longitudinal analysis with a structural equation model].  

PubMed

Most studies focusing on the antecedents and consequences of workplace bullying have used a cross-sectional design, which impedes determining the causality of the relationships. In the present work, we analyzed, by means of structural equation models, the relationship between workplace bullying and some variables that are considered antecedents (interpersonal conflicts, role ambiguity, role conflict, and workplace social support) or consequences (health complaints and inclination to absenteeism from work) of this phenomenon. Multicenter study with two phases. The sample consisted of 696 employees from 66 centers. Workplace bullying was assessed by means of the "Mobbing-UNIPSICO" questionnaire, and the other variables with frequency scales. The cross-sectional models indicated a significant association between role conflict, workplace social support, and workplace bullying in both study periods. Concerning the longitudinal relationships, only workplace social support was a significant predictor of workplace bullying, which, in turn, was a cross-sectional and longitudinal predictor of workers' health complaints. Our results show the mediating effect of workplace bullying between certain work conditions and health complaints, and it is recommendable to replicate these findings in a multi-occupational sample. PMID:22047848

Carretero Domínguez, Noelia; Gil-Monte, Pedro Rafael; Luciano Devis, Juan Vicente

2011-11-01

170

Linking impulsivity to dysfunctional thought control and insomnia: a structural equation model.  

PubMed

According to cognitive models of insomnia, excessive mental activity at bedtime may be viewed as an important impediment to the process of falling asleep. A further assumption of these models is that 'cognitive arousal' may be perpetuated and exacerbated by counterproductive strategies of thought management. As yet, little is known about factors that may predispose people to rely on these strategies when confronted with thoughts that keep them awake at night. This study examined the relations between impulsivity, use of different thought-control strategies and insomnia severity. A sample of 391 university students completed the UPPS Impulsive Behavior Scale, the Thought Control Questionnaire Insomnia-Revised and the Insomnia Severity Index. Correlation analyses revealed that two facets of impulsivity (urgency and lack of perseverance), two strategies of thought control (aggressive suppression and worry) and insomnia severity were positively associated. Follow-up structural equation modeling analyses showed that the two mentioned thought-control strategies mediated the effects of the two facets of impulsivity on sleep problems. These findings extend existing cognitive accounts of insomnia by suggesting how predisposing and perpetuating factors may be related: specific personality traits may incline individuals to respond with dysfunctional thought-control strategies to unwanted mental activity at night. PMID:19659917

Schmidt, Ralph E; Gay, Philippe; Ghisletta, Paolo; VAN DER Linden, Martial

2009-07-29

171

Confirming the factor structure of the alcohol and alcohol problems questionnaire (AAPPQ) in a sample of baccalaureate nursing students.  

PubMed

The Alcohol and Alcohol Problems Perception Questionnaire (AAPPQ) is a multi-dimensional measure of clinicians' attitudes toward working with patients with alcohol problems. In the past 35 years, five- and six-subscale versions and a short version of the AAPPQ have been published. While the reliability of the AAPPQ subscales has remained acceptable, the factor structure has not been verified using confirmatory techniques. In the current study, we split a sample of 299 baccalaureate nursing students to use exploratory (EFA) and confirmatory factor analyses (CFA). When compared to the original six-factor solution and an imposed six-factor structure in CFA, the EFA seven-factor solution with three original items (19, 20, and 25) removed had the best model fit. PMID:23633092

Terhorst, Lauren; Gotham, Heather J; Puskar, Kathryn R; Mitchell, Ann M; Talcott, Kimberly S; Braxter, Betty; Hagle, Holly; Fioravanti, Marie; Woomer, Gail R

2013-04-30

172

Initial validation of the Spanish childhood trauma questionnaire-short form: factor structure, reliability and association with parenting.  

PubMed

The present study examines the internal consistency and factor structure of the Spanish version of the Childhood Trauma Questionnaire-Short Form (CTQ-SF) and the association between the CTQ-SF subscales and parenting style. Cronbach's ? and confirmatory factor analyses (CFA) were performed in a female clinical sample (n = 185). Kendall's ? correlations were calculated between the maltreatment and parenting scales in a subsample of 109 patients. The Spanish CTQ-SF showed adequate psychometric properties and a good fit of the 5-factor structure. The neglect and abuse scales were negatively associated with parental care and positively associated with overprotection scales. The results of this study provide initial support for the reliability and validity of the Spanish CTQ-SF. PMID:23266990

Hernandez, Ana; Gallardo-Pujol, David; Pereda, Noemí; Arntz, Arnoud; Bernstein, David P; Gaviria, Ana M; Labad, Antonio; Valero, Joaquín; Gutiérrez-Zotes, Jose Alfonso

2012-12-24

173

Factor structure of the Sociocultural Attitudes Towards Appearance Questionnaire-3 (SATAQ-3) among adolescent boys in China.  

PubMed

There is considerable evidence that mass media portrayals of body image contribute to body dissatisfaction, yet the assessment of perceived media influences has been examined fleetingly in highly populated, non-Western cultures, particularly among young males. This research examined the factor structure of the Sociocultural Attitudes Towards Appearance Questionnaire-3 (SATAQ-3) among adolescent boys in China. In an initial exploratory factor analysis (N=719), a four factor solution emerged with components reflecting General Pressure-Internalization, Sources of Appearance Information, Pressure-Internalization of an Athletic Ideal, and Pressure to be Thin. Subsequently, confirmatory factor analyses in a new sample (n=749) assessed fits of the derived four factor model, a three factor variant, and alternatives reflecting "Western" and "Malay" SATAQ-3 solutions. The derived four factor solution had the most acceptable structure across several fit indices. Patterns of correlation with other self-report measures also provided preliminary support for the validity of the derived solution. PMID:20800561

Jackson, Todd; Chen, Hong

2010-08-30

174

Factor structure of the Eating Disorder Examination Questionnaire (EDE-Q) in male and female college athletes.  

PubMed

The study explored the psychometric properties of the Eating Disorder Examination Questionnaire (EDE-Q) among 1637 university students. Participants were divided into male (n=432) and female (n=544) competitive athletes, and male (n=229) and female (n=429) comparison groups comprised of individuals who had not engaged in competitive sports for at least one year. All groups were subjected to confirmatory factor analysis (CFA) to test the fit of the published factor structure in this population, and then exploratory FA (EFA). A three-factor solution was the best fit for three out of four groups, with a two-factor solution providing best fit for the male comparison group. The first factor for all groups resembled a combined Shape and Weight Concern subscale. The factor structure among male and female competitive athletes was remarkably similar; however, non-competitive athletic/low activity males appear qualitatively different from other groups. PMID:23453695

Darcy, Alison M; Hardy, Kristina K; Crosby, Ross D; Lock, James; Peebles, Rebecka

2013-03-01

175

Impact of organizational structure on nurses’ job satisfaction: A questionnaire survey  

Microsoft Academic Search

Background Nurses’ job satisfaction is an important issue because of its impact on the quality of the nursing job. Therefore, it receives a lot of attention in the international nursing literature but insight into the sources of nurses’ job satisfaction is yet insufficient, in particular for sources related to organizational structure. ObjectivesWe contribute by investigating the relationship between the organizational

A. WILLEM; M. BUELENS; I. DE JONGHE

2005-01-01

176

Hamiltonian structure for the Charney-Hasegawa-Mima equation in the asymptotic model regime  

NASA Astrophysics Data System (ADS)

We show that the Charney-Hasegawa-Mima (CHM) equation in the asymptotic model (CHM-AM) regime possesses the non-canonical Hamiltonian structure. The CHM-AM corresponds to the CHM equation in the asymptotic limit of length scales large compared to the Rossby deformation radius. It is shown that the Hamiltonian structure of the CHM-AM cannot be derived directly from that of the CHM equation by taking a simple limit of a length scale. Both the two-dimensional (2-D) Euler equation and the CHM-AM are regarded as special cases of a generalized 2-D fluid system, the so-called ?-turbulence system. The existence of the Hamiltonian structure of the CHM-AM obtained in this study and that of the 2-D Euler equation implies the existence of the Hamiltonian structure of the ?-turbulence system.

Sueyoshi, Masakazu; Iwayama, Takahiro

2007-04-01

177

Mathematical structure of tetrad equations for vacuum relativity  

SciTech Connect

The tetrad partial differential equations formulated by Buchman and Bardeen for vacuum gravity are shown to be well posed by calculation of the Cartan characters of an associated exterior differential system. Gauge specializations are discussed. A Cartan 4-form is found for this field theory, together with its intrinsic version the Lagrangian density.

Estabrook, Frank B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109 (United States)

2005-02-15

178

On Bayesian structural inference in a simultaneous equation model  

Microsoft Academic Search

Econometric issues that are considered fundamental in the development of Bayesian structuralinference within a Simultaneous Equation Model are surveyed. The difficulty of specifying prior information which is of interest to economists and which yields tractable posterior and predictive distributions has started this line of research. A major issue is the nonstandard shape of the likelihood due to reduced rank restrictions.

Herman K. van Dijk

2002-01-01

179

Discrete structures equivalent to nonlinear Dirichlet and wave equations  

NASA Astrophysics Data System (ADS)

The Amann-Conley-Zehnder (ACZ) reduction is a global Lyapunov-Schmidt reduction for PDEs based on spectral decomposition. ACZ has been applied in conjunction to diverse topological methods, to derive existence and multiplicity results for Hamiltonian systems, for elliptic boundary value problems, and for nonlinear wave equations. Recently, the ACZ reduction has been translated numerically for semilinear Dirichlet problems and for modeling molecular dynamics, showing competitive performances with standard techniques. In this paper, we apply ACZ to a class of nonlinear wave equations in {mathbb{T}^n}, attaining to the definition of a finite lattice of harmonic oscillators weakly nonlinearly coupled exactly equivalent to the continuum model. This result can be thought as a thermodynamic limit arrested at a small but finite scale without residuals. Reduced dimensional models reveal the macroscopic scaled features of the continuum, which could be interpreted as collective variables.

Lovison, Alberto; Cardin, Franco; Bobbo, Alessia

2009-06-01

180

Structure of entropy solutions to the eikonal equation  

Microsoft Academic Search

.   In this paper, we establish rectifiability of the jump set of an S\\u000a 1–valued conservation law in two space–dimensions. This conservation law is a reformulation of the eikonal equation and is\\u000a motivated by the singular limit of a class of variational problems. The only assumption on the weak solutions is that the\\u000a entropy productions are (signed) Radon measures, an assumption which

Camillo De Lellis; Felix Otto

2003-01-01

181

Hyperbolic heat conduction equation for materials with a nonhomogeneous inner structure  

Microsoft Academic Search

The physical meaning of the constant Ï in Cattaneo and Vernotte's equation for materials with a nonhomogeneous inner structure has been considered. An experimental determination of the constant Ï has been proposed and some values for selected products have been given. The range of differences in the description of heat transfer by parabolic and hyperbolic heat conduction equations has been

W. Kaminski

1990-01-01

182

An Explicit Solution of the Power Balance Equations of Structure Preserving Power System Models  

Microsoft Academic Search

In this paper, we consider the widely popular structure-preserving models used to describe the dynamic behavior of multimachine power systems. These models consist of differential-algebraic equations, where the algebraic constraints stem from the power flow balance between generators, loads, and lines. Our main contribution is the explicit computation of a solution for these algebraic equations under the assumption that the

Wissam Dib; Andrey E. Barabanov; Romeo Ortega; FranÇoise Lamnabhi-Lagarrigue

2009-01-01

183

Solving the Sayre equations for centrosymmetric structures with a genetic algorithm  

NASA Astrophysics Data System (ADS)

A new method employing Sayre's equations and a genetic algorithm to solve the phase problem is developed for centrosymmetric structures. Compared to simulated annealing, a genetic algorithm is more efficient.

Zhou, Y.; Su, W.-P.

2004-07-01

184

Boundary Values and Finite Difference Methods for the Single Factor Term Structure Equation  

Microsoft Academic Search

We study the classical single factor term structure equation for models that predict non-negative interest rates. For these models we develop a fast and accurate finite difference method (FD) using the appropriate boundary conditions at zero.

Erik Ekström; Per Lötstedt; Johan Tysk

2009-01-01

185

Enhancements of Systems Based on Bayesian Networks and Structural Equation Models for Command and Control Support.  

National Technical Information Service (NTIS)

The performed project focused on a new paradigm of planning systems that are based on a combination of Bayesian networks and structural equation models. We focused on theoretical issues that surround combining the two in a practical planning system, devel...

M. J. Druzdzel

2000-01-01

186

Systems Based on Bayesian Belief Networks and Structural Equation Models for Command and Control Support.  

National Technical Information Service (NTIS)

The performed project focused on a new paradigm of planning systems that are based on a combination of Bayesian networks and structural equation models. We focused on theoretical issues that surround combining the two in a practical planning system, devel...

M. J. Druzdzel

2000-01-01

187

The Relativistic Equations of Stellar Structure and Evolution. Stars with Degenerate Neutron Cores. 1: Structure of Equilibrium Models.  

National Technical Information Service (NTIS)

The general relativistic equations of stellar structure and evolution are reformulated in a notation which makes easy contact with Newtonian theory. Also, a general relativistic version of the mixing-length formalism for convection is presented. Finally, ...

K. S. Thorne A. N. Zytkow

1976-01-01

188

Development of a Structural Equation Model for ride comfort of the Korean high-speed railway  

Microsoft Academic Search

This study is aimed at developing a Structural Equation Model for the ride comfort of the high-speed railway launched in South Korea (KTX: The Korea Train eXpress). The Structural Equation Model (SEM) was used to systematically explain passenger ride comfort and quantify the impacts and values of various factors found to be related to the ride comfort of a high-speed

Joo Hwan Lee; Beom Suk Jin; Yonggu Ji

2009-01-01

189

On Bayesian estimation and model comparison of an integrated structural equation model  

Microsoft Academic Search

In this paper, we introduce a Bayesian approach to the estimation and model comparison of an integrated two-level nonlinear structural equation model with mixed continuous, dichotomous, and ordered categorical data that may be missing at random. This general model can accommodate nonlinearities of latent variables and the effects of fixed covariates on measurement and structural equations in within-groups and between-groups

Sik-yum Lee; Xin-yuan Song

2008-01-01

190

A Robust Bayesian Approach for Structural Equation Models with Missing Data  

Microsoft Academic Search

In this paper, normal\\/independent distributions, including but not limited to the multivariate t distribution, the multivariate contaminated distribution, and the multivariate slash distribution, are used to develop a\\u000a robust Bayesian approach for analyzing structural equation models with complete or missing data. In the context of a nonlinear\\u000a structural equation model with fixed covariates, robust Bayesian methods are developed for estimation

Sik-Yum Lee; Ye-Mao Xia

2008-01-01

191

Use of Prior Knowledge in a Non-Gaussian Method for Learning Linear Structural Equation Models  

Microsoft Academic Search

\\u000a We discuss causal structure learning based on linear structural equation models. Conventional learning methods most often\\u000a assume Gaussianity and create many indistinguishable models. Therefore, in many cases it is difficult to obtain much information\\u000a on the structure. Recently, a non-Gaussian learning method called LiNGAM has been proposed to identify the model structure\\u000a without using prior knowledge on the structure. However,

Takanori Inazumi; Shohei Shimizu; Takashi Washio

2010-01-01

192

Numerical simulation of reflecting structures by solution of the two-dimensional Helmholtz equation  

SciTech Connect

A method is described for modeling two-dimensional reflecting structures based on a solution of the scalar Helmholtz equation. The equation is solved by use of an alternating-direction-implicit iterative method together with a semioptimum sequence of acceleration parameters similar to those introduced decades ago for the solution of elliptic equations with positive-definite operators. The resulting technique is efficient and simple to program, permits the simulation of complex structures with modest storage requirements, and is of very general applicability.

Hadley, G.R. (Sandia National Laboratories, Albuquerque, New Mexico 87185-5800 (United States))

1994-01-15

193

The Factor Structure and Factorial Invariance of the 12-Item General Health Questionnaire (GHQ-12) across Time: Evidence from Two Community-Based Samples  

ERIC Educational Resources Information Center

|This study provides new knowledge about the factor structure of the 12-item General Health Questionnaire (GHQ-12; D. Goldberg, 1972) through the application of confirmatory factor analysis to longitudinal data, thereby enabling investigation of the factor structure, its invariance across time, and the rank-order stability of the factors. Two…

Makikangas, Anne; Feldt, Taru; Kinnunen, Ulla; Tolvanen, Asko; Kinnunen, Marja-Liisa; Pulkkinen, Lea

2006-01-01

194

Age-structured Trait Substitution Sequence Process and Canonical Equation  

Microsoft Academic Search

We are interested in a stochastic model of trait and age-structured population undergoing mutation and selection. We start with a continuous time, discrete individual-centered population process. Taking the large population and rare mutations limits under a well-chosen time-scale separation condition, we obtain a jump process that generalizes the Trait Substitution Sequence process describing Adaptive Dynamics for populations without age structure.

Sylvie Méléard; Viet Chi Tran

2007-01-01

195

System Characteristics, Satisfaction and E-Learning Usage: A Structural Equation Model (SEM)  

ERIC Educational Resources Information Center

|With the advent of the Internet, more and more public universities in Malaysia are putting in effort to introduce e-learning in their respective universities. Using a structured questionnaire derived from the literature, data was collected from 250 undergraduate students from a public university in Penang, Malaysia. Data was analyzed using AMOS…

Ramayah, T.; Lee, Jason Wai Chow

2012-01-01

196

Risk Factors of Work-related Upper Extremity Musculoskeletal Disorders in Male Shipyard Workers: Structural Equation Model Analysis  

PubMed Central

Objectives This study was conducted to develop a model describing the interaction between lifestyle, job, and postural factors and parts of the upper extremities in shipyard workers. Methods A questionnaire survey was given to 2,140 workers at a shipyard in Ulsan City. The questionnaire consisted of questions regarding the subjects' general characteristics, lifestyle, tenure, physical burden, job control, posture and musculoskeletal symptoms. The overall relationship between variables was analyzed by a structural equation model (SEM). Results The positive rate of upper extremity musculoskeletal symptoms increased in employees who worked longer hours, had severe physical burden, and did not have any control over their job. Work with a more frequent unstable posture and for longer hours was also associated with an increased positive rate of musculoskeletal symptoms. Multiple logistic regression analysis showed that unstable posture and physical burden were closely related to the positive rate of musculoskeletal symptoms after controlling for age, smoking, drinking, exercise, tenure, and job control. In SEM analysis, work-related musculoskeletal disease was influenced directly and indirectly by physical and job stress factors, lifestyle, age, and tenure (p < 0.05). The strongest correlations were found between physical factors and work-related musculoskeletal disease. Conclusion The model in this study provides a better approximation of the complexity of the actual relationship between risk factors and work-related musculoskeletal disorders. Among the variables evaluated in this study, physical factors (work posture) had the strongest association with musculoskeletal disorders.

Park, Byung-Chan; Kim, Eun-A; Kim, Soo Geun

2010-01-01

197

The Smoking Consequences Questionnaire: Factor structure and predictive validity among Spanish-speaking Latino smokers in the United States  

PubMed Central

Introduction: Much of the existing research on smoking outcome expectancies has been guided by the Smoking Consequences Questionnaire (SCQ ). Although the original version of the SCQ has been modified over time for use in different populations, none of the existing versions have been evaluated for use among Spanish-speaking Latino smokers in the United States. Methods: The present study evaluated the factor structure and predictive validity of the 3 previously validated versions of the SCQ—the original, the SCQ-Adult, and the SCQ-Spanish, which was developed with Spanish-speaking smokers in Spain—among Spanish-speaking Latino smokers in Texas. Results: The SCQ-Spanish represented the least complex solution. Each of the SCQ-Spanish scales had good internal consistency, and the predictive validity of the SCQ-Spanish was partially supported. Nearly all the SCQ-Spanish scales predicted withdrawal severity even after controlling for demographics and dependence. Boredom Reduction predicted smoking relapse across the 5- and 12-week follow-up assessments in a multivariate model that also controlled for demographics and dependence. Discussion: Our results support use of the SCQ-Spanish with Spanish-speaking Latino smokers in the United States.

Costello, Tracy J.; Mazas, Carlos; Cofta-Woerpel, Ludmila; Mejia, Luz Maria; Wetter, David W.

2009-01-01

198

End-user computing effectiveness: A structural equation model  

Microsoft Academic Search

The paper reports the results of a field study investigating the determinants of End-User Computing (EUC) effectiveness among 187 end-users. A conceptual structural model was developed and tested using Partial Least Squares (PLS). The results show that computer anxiety and attitudes toward EUC are significantly affected by work\\/life experiences, end-user training, computer experience, and information center support. Computer anxiety also

M. Igbaria

1990-01-01

199

Using Mx to Analyze Cross-Level Effects in Two-Level Structural Equation Models  

ERIC Educational Resources Information Center

|Two-level data sets are frequently encountered in social and behavioral science research. They arise when observations are drawn from a known hierarchical structure, such as when individuals are randomly drawn from groups that are randomly drawn from a target population. Although 2-level data analysis in the context of structural equation

Bai, Yun; Poon, Wai-Yin

2009-01-01

200

Solution of linear systems of equations with a structural analysis code on the NAS CRAY2  

Microsoft Academic Search

Two methods for solving linear systems of equations on the NAS Cray-2 are described. One is a direct method; the other is an iterative method. Both methods exploit the architecture of the Cray-2, particularly the vectorization, and are aimed at structural analysis applications. To demonstrate and evaluate the methods, they were installed in a finite element structural analysis code denoted

E. L. Poole; A. L. Overman

1988-01-01

201

Cowles commission structural equation approach in light of nonstationary time series analysis  

Microsoft Academic Search

We review the advancement of nonstationary time series analysis from the perspective of Cowles Commission structural equation approach. We argue that despite the rich repertoire nonstationary time series analysis provides to analyze how do variables respond dynamically to shocks through the decomposition of a dynamic system into long-run and short-run relations, nonstationarity does not invalid the classical concerns of structural

Cheng Hsiao

2007-01-01

202

Functional structure model of human body and Yinyang-Wuxing equations  

Microsoft Academic Search

The functional structure of human body is composed of five interacting functional subsystems. The connections between them are described by Wuxing theory. Wuxing diagram and Wuxing equations of human body are presented. The dynamics of human body is studied. Self-organization structure model of Jingluo is considered. Experimental tests of dynamics of human body are proposed.

Li Fuli

1987-01-01

203

Functional structure model of human body and Yinyang-Wuxing equations  

NASA Astrophysics Data System (ADS)

The functional structure of human body is composed of five interacting functional subsystems. The connections between them are described by Wuxing theory. Wuxing diagram and Wuxing equations of human body are presented. The dynamics of human body is studied. Self-organization structure model of Jingluo is considered. Experimental tests of dynamics of human body are proposed.

Fuli, Li

1987-12-01

204

Shock structures in time-averaged patterns for the kuramoto-sivashinsky equation  

PubMed

The Kuramoto-Sivashinsky equation with fixed boundary conditions is numerically studied. Shocklike structures appear in the time-averaged patterns for some parameter range of the boundary values. Effective diffusion constant is estimated from the relation of the width and the height of the shock structures. PMID:11138191

Sakaguchi

2000-12-01

205

Direct and Indirect Effects of Parental Influence upon Adolescent Alcohol Use: A Structural Equation Modeling Analysis  

ERIC Educational Resources Information Center

|A model incorporating the direct and indirect effects of parental monitoring on adolescent alcohol use was evaluated by applying structural equation modeling (SEM) techniques to data on 4,765 tenth-graders in the 2001 Monitoring the Future Study. Analyses indicated good fit of hypothesized measurement and structural models. Analyses supported…

Kim, Young-Mi; Neff, James Alan

2010-01-01

206

Direct and Indirect Effects of Parental Influence upon Adolescent Alcohol Use: A Structural Equation Modeling Analysis  

ERIC Educational Resources Information Center

A model incorporating the direct and indirect effects of parental monitoring on adolescent alcohol use was evaluated by applying structural equation modeling (SEM) techniques to data on 4,765 tenth-graders in the 2001 Monitoring the Future Study. Analyses indicated good fit of hypothesized measurement and structural models. Analyses supported both…

Kim, Young-Mi; Neff, James Alan

2010-01-01

207

The Impact of Specification Error on the Estimation, Testing, and Improvement of Structural Equation Models  

Microsoft Academic Search

The purpose of this paper is to assess the impact of misspecification on the estimation, testing, and improvement of structural equation models. A population study is con- ducted whereby a prototypical latent variable model is misspecified in various ways. Measurement model and structural model misspecifications are considered separately and together. The maximum likelihood estimator (ML) is compared to a limited

David Kaplan

1988-01-01

208

Direct and Indirect Effects of Parental Influence Upon Adolescent Alcohol Use: A Structural Equation Modeling Analysis  

Microsoft Academic Search

A model incorporating the direct and indirect effects of parental monitoring on adolescent alcohol use was evaluated by applying structural equation modeling (SEM) techniques to data on 4,765 tenth-graders in the 2001 Monitoring the Future Study. Analyses indicated good fit of hypothesized measurement and structural models. Analyses supported both direct and indirect effects of parental monitoring on adolescent alcohol use.

Young-Mi Kim; James Alan Neff

2010-01-01

209

A Stepwise Structural Equation Modeling Algorithm to Recon struct Genetic Networks  

Microsoft Academic Search

Motivation: A stepwise structural equation modeling algorithm (SSEM) has been developed to infer genetic networks from time course microarray data. Besides observed variables, SSEM also incorporates hidden variables in order to depict regulations from proteins and other molecules that are not measured by microarrays. SSEM can learn the structure of a genetic network from microarray data. We have simulated data

Grace S. Shieh; Chung-Ming Chen; Ching-Yun Yu; Juiling Huang; Woei-Fuh Wang

210

Statistical analysis of nonlinear structural equation models with continuous and polytomous data  

Microsoft Academic Search

A general nonlinear structural equation model with mixed continuous and poly- tomous variables is analysed. A Bayesian approach is proposed to estimate simultaneously the thresholds, the structural parameters and the latent variables. To solve the computational dif® culties involved in the posterior analysis, a hybrid Markov chain Monte Carlo method that combines the Gibbs sampler and the Metropolis± Hasting algorithm

Sik-Yum Lee; Hong-Tu Zhu

2000-01-01

211

Analysis of structural equation model with ignorable missing continuous and polytomous data  

Microsoft Academic Search

The main purpose of this article is to develop a Bayesian approach for structural equation models with ignorable missing continuous and polytomous data. Joint Bayesian estimates of thresholds, structural parameters and latent factor scores are obtained simultaneously. The idea of data augmentation is used to solve the computational difficulties involved. In the posterior analysis, in addition to the real missing

Xin-Yuan Song; Sik-Yum Lee

2002-01-01

212

Structural Equation Modeling in Assessing Students' Understanding of the State Changes of Matter  

ERIC Educational Resources Information Center

|In this study, structural equation modeling (SEM) is applied to an instrument assessing students' understanding of the particulate nature of matter, the collective properties and physical changes, such as melting, evaporation, boiling and condensation. The structural relationships among particular groups of items were investigated. In addition,…

Stamovlasis, Dimitrios; Tsitsipis, Georgios; Papageorgiou, George

2012-01-01

213

Electromagnetic wave propagation in periodic structures: Bloch wave solution of Maxwell's equations  

Microsoft Academic Search

We examine the propagation of electromagnetic waves in periodic dielectric structures by solving the vector Maxwell equations with the plane-wave method. Contrary to experimental reports, as well as results of scalar-wave calculations, we do not find a true gap extending throughout the Brillouin zone in the fcc structure. However, there is a depletion in the photon density of states, seemingly

Ze Zhang; Sashi Satpathy

1990-01-01

214

A confirmatory approach to examining the factor structure of the Strengths and Difficulties Questionnaire (SDQ): a large scale cohort study.  

PubMed

The aim of this study was to examine the factor structure of the Strengths and Difficulties Questionnaire (SDQ) using a Structural Confirmatory Factor Analytic approach. The Danish translation of the SDQ was distributed to 71,840 parents and teachers of 5-7 and 10-12-year-old boys and girls from four large scale cohorts. Three theoretical models were examined: 1. a model with five first order factors (i.e., hyperactivity/inattention, conduct, emotional, peer problems and prosocial), 2. a model adding two internalising and externalising second order factors to model 1, and 3. a model adding a total difficulties second order factor to model 1. Model fits were evaluated, multi-group analyses were carried out and average variance extracted (AVE) and composite reliability (CR) estimates were examined. In this general population sample, low risk sample models 1 and 2 showed similar good overall fits. Best model fits were found when two positively worded items were allowed to cross load with the prosocial scale, and cross loadings were allowed for among three sets of indicators. The analyses also revealed that model fits were slightly better for teachers than for parents and better for older children than for younger children. No convincing differences were found between boys and girls. Factor loadings were acceptable for all groups, especially for older children rated by teachers. Some emotional, peer, conduct and prosocial subscale problems were revealed for younger children rated by parents. The analyses revealed more internal consistency for older children rated by teachers than for younger children rated by parents. It is recommended that model 1 comprising five first order factors, or alternatively model 2 with additionally two internalising/externalising second order factors, should be used when employing the SDQ in low risk epidemiological samples. PMID:23008011

Niclasen, Janni; Skovgaard, Anne Mette; Andersen, Anne-Marie Nybo; Sømhovd, Mikael Julius; Obel, Carsten

2013-04-01

215

The Rivermead Post Concussion Symptoms Questionnaire  

Microsoft Academic Search

Objective  To investigate the factor structure of the Rivermead Post Concussion Symptoms Questionnaire (RPQ) among individuals seen as\\u000a part of routine follow-up following traumatic brain injury.\\u000a \\u000a \\u000a \\u000a Methods  RPQ data from 168 participants was examined (mean age 35.2, SD 14.3; 89% with post traumatic amnesia duration < 24 hours)\\u000a six months after admission to an Accident & Emergency Department following TBI. Structural equation modelling was

Seb Potter; Eleanor Leigh; Derick Wade; Simon Fleminger

2006-01-01

216

Ground-motion prediction equations (GMPEs) for inelastic response and structural behaviour factors  

Microsoft Academic Search

The objective of this paper is to present ground-motion prediction equations describing constant-ductility inelastic spectral\\u000a ordinates and structural behaviour factors. These equations are intended for application within the framework of Eurocode\\u000a 8. Most of the strong-motion data used in the present work is obtained from the ISESD (Internet Site for European Strong-motion\\u000a Data) databank. Present analysis includes ground motion records

R. Rupakhety; R. Sigbjörnsson

2009-01-01

217

"Smoluchowski type" Equations for Modelling of Air Separation by Membranes with Various Structure  

NASA Astrophysics Data System (ADS)

The problem of a membrane air separation in the presence of a magnetic field, is considered. Paramagnetism of oxygen and diamagnetic behaviour of nitrogen form the basis for air separation. A new concept of polymer membranes filled with neodymium powder and magnetized ("magnetic membranes"), was applied. The Smoluchowski equation for oxygen, and simple diffusion equation for nitrogen behaviour in the air have been used. Multifractal analysis of structure and morphology of membranes were applied to optical microscopy images.

Rybak, A.; Krasowska, M.; Strzelewicz, A.; Grzywna, Z. J.

2009-05-01

218

Factorial structure and internal consistency of the German TEMPS-A scale: validation against the NEO-FFI questionnaire  

Microsoft Academic Search

Background: The purpose of the study was to evaluate the psychometric properties of the German version of the TEMPS-A questionnaire. Besides the reliability of the temperament scales, validity was the focus of interest. Therefore, the relationship between the TEMPS-A and the well-established personality questionnaire NEO-FFI, whose factors show theoretical overlap with temperaments, was investigated. Method: A total of 227 students

Raffaela Blöink; Peter Brieger; Hagop S. Akiskal; Andreas Marneros

2005-01-01

219

Adjustment to College as Measured by the Student Adaptation to College Questionnaire: A Quantitative Review of Its Structure and Relationships with Correlates and Consequences  

ERIC Educational Resources Information Center

|This paper presents a meta-analytic review (k = 237, N = 44,668) of the adjustment to college literature. The review, based on studies using the Student Adaptation to College Questionnaire, is organized around three primary themes: (1) the structure of students' adjustment to college, (2) the relationship of adjustment to college constructs with…

Crede, Marcus; Niehorster, Sarah

2012-01-01

220

Factor Structure of the Reactive-Proactive Aggression Questionnaire in Turkish Children and Gender, Grade-Level, and Socioeconomic Status Differences in Reactive and Proactive Aggression  

ERIC Educational Resources Information Center

The present study aimed to evaluate the factor structure of the Reactive-Proactive Aggression Questionnaire (RPQ) with Turkish children, and to investigate gender, grade-level, and socioeconomic status (SES) differences in reactive and proactive aggression. Participants consisted of 1,081 Turkish children (544 boys and 537 girls) aged 9 to 14…

Uz Bas, Asli; Yurdabakan, Irfan

2012-01-01

221

Factor Structure of the Reactive-Proactive Aggression Questionnaire in Turkish Children and Gender, Grade-Level, and Socioeconomic Status Differences in Reactive and Proactive Aggression  

ERIC Educational Resources Information Center

|The present study aimed to evaluate the factor structure of the Reactive-Proactive Aggression Questionnaire (RPQ) with Turkish children, and to investigate gender, grade-level, and socioeconomic status (SES) differences in reactive and proactive aggression. Participants consisted of 1,081 Turkish children (544 boys and 537 girls) aged 9 to 14…

Uz Bas, Asli; Yurdabakan, Irfan

2012-01-01

222

Simple, Efficient and Distribution-free Approach to Interaction Effects in Complex Structural Equation Models  

Microsoft Academic Search

Structural equation models with mean structure and non-linear constraints are the most frequent choice for estimating interaction\\u000a effects when measurement errors are present. This article proposes eliminating the mean structure and all the constraints\\u000a but one, which leads to a more easily handled model that is more robust to non-normality and more general as it can accommodate\\u000a endogenous interactions and

Germà Coenders; Joan M. Batista-Foguet; Willem E. Saris

2008-01-01

223

Solving the Sayre equations for centrosymmetric structures with a genetic algorithm.  

PubMed

Sayre's equations give a set of relationships that exist among the structure factors of an equal-atom structure. In order to obtain the correct phases of the structure factors, a genetic algorithm is used to minimize a least-squares residual of Sayre's equations. In the genetic algorithm, a phase is treated as a gene and the whole set of phases is considered as a chromosome. Every chromosome is relaxed to a nearby local minimum by quenching after being produced from a previous generation. Trial calculations for a structure containing 92 non-H equal atoms with synthetic data and another structure containing 62 non-H equal atoms with real data are presented. Compared to simulated annealing, a genetic algorithm is a more efficient means of global optimization. PMID:15218207

Zhou, Yi; Su, Wu-Pei

2004-06-24

224

Evaluation of structural equation mixture models Parameter estimates and correct class assignment  

PubMed Central

Structural Equation Mixture Models(SEMMs) are latent class models that permit the estimation of a structural equation model within each class. Fitting SEMMs is illustrated using data from one wave of the Notre Dame Longitudinal Study of Aging. Based on the model used in the illustration, SEMM parameter estimation and correct class assignment are investigated in a large scale simulation study. Design factors of the simulation study are (im)balanced class proportions, (im)balanced factor variances, sample size, and class separation. We compare the fit of models with correct and misspecified within-class structural relations. In addition, we investigate the potential to fit SEMMs with binary indicators. The structure of within-class distributions can be recovered under a wide variety of conditions, indicating the general potential and flexibility of SEMMs to test complex within-class models. Correct class assignment is limited.

Tueller, Stephen; Lubke, Gitta

2009-01-01

225

An Assessment of Practical Solutions for Structural Equation Modeling with Complex Sample Data  

ERIC Educational Resources Information Center

|This article discusses 5 approaches that secondary researchers might use to obtain robust estimates in structural equation modeling analyses when using data that come from large survey programs. These survey programs usually collect data using complex sampling designs and estimates obtained from conventional analyses that ignore the dependencies…

Stapleton, Laura M.

2006-01-01

226

Parsimonious Structural Equation Models for Repeated Measures Data, with Application to the Study of Consumer Preferences  

ERIC Educational Resources Information Center

Recent research reflects a growing awareness of the value of using structural equation models to analyze repeated measures data. However, such data, particularly in the presence of covariates, often lead to models that either fit the data poorly, are exceedingly general and hard to interpret, or are specified in a manner that is highly data…

Elrod, Terry; Haubl, Gerald; Tipps, Steven W.

2012-01-01

227

How does desktop virtual reality enhance learning outcomes? A structural equation modeling approach  

Microsoft Academic Search

This study examined how desktop virtual reality (VR) enhances learning and not merely does desktop VR influence learning. Various relevant constructs and their measurement factors were identified to examine how desktop VR enhances learning and the fit of the hypothesized model was analyzed using structural equation modeling. The results supported the indirect effect of VR features to the learning outcomes,

Elinda Ai-Lim Lee; Kok Wai Wong; Chun Che Fung

2010-01-01

228

A Structural Equation Model of Burnout and Job Exit among Child Protective Services Workers.  

ERIC Educational Resources Information Center

|Uses a structural equation model to examine the three elements of the Maslach Burnout Inventory (MBI)--emotional exhaustion, depersonalization, and personal accomplishment--in relation to job exit among child protective services workers over a 15-month period. The model was supported, showing the relevance of all three MBI elements of job exit.…

Drake, Brett; Yadama, Gautam N.

1996-01-01

229

Self-Conscious Emotions in Response to Perceived Failure: A Structural Equation Model  

ERIC Educational Resources Information Center

|This study explored the occurrence of self-conscious emotions in response to perceived academic failure among 4th-grade students from the United States and Bulgaria, and the author investigated potential contributors to such negative emotional experiences. Results from structural equation modeling indicated that regardless of country, negative…

Bidjerano, Temi

2010-01-01

230

A Systematic Review of Structural Equation Modelling in Social Work Research  

Microsoft Academic Search

Structural equation modelling (SEM) is serving an increasingly important role in developing knowledge for the social work profession. Numerous advances have made the software more user-friendly, enabling users to conduct analyses without fully understanding the underlying assumptions or the implications from their analytic decisions. Unlike other fields, there have not been any published reviews in social work research that systematically

Baorong Guo; Brian E. Perron; David F. Gillespie

2009-01-01

231

A Program Implementing Mardia's Multivariate Normality Test for Use in Structural Equation Modeling with Latent Variables.  

ERIC Educational Resources Information Center

Presents KANT, a FORTRAN 77 software program that tests assumptions of multivariate normality in a data set. Based on the test developed by M. V. Mardia (1985), the KANT program is useful for those engaged in structural equation modeling with latent variables. (SLD)

MacIntosh, Randall

1997-01-01

232

Painleve singularity structure analysis of three component Gross-Pitaevskii type equations  

SciTech Connect

In this paper, we have studied the integrability nature of a system of three-coupled Gross-Pitaevskii type nonlinear evolution equations arising in the context of spinor Bose-Einstein condensates by applying the Painleve singularity structure analysis. We show that only for two sets of parametric choices, corresponding to the known integrable cases, the system passes the Painleve test.

Kanna, T.; Sakkaravarthi, K. [Department of Physics, Bishop Heber College, Tiruchirapalli 620 017 (India); Kumar, C. Senthil [Department of Physics, VMKV Engineering College, Periaseeragapadi, Salem 636 308 (India); Lakshmanan, M. [Centre for Nonlinear Dynamics, Bharathidasan University, Tiruchirapalli 620 024 (India); Wadati, M. [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

2009-11-15

233

The Relative Performance of Full Information Maximum Likelihood Estimation for Missing Data in Structural Equation Models.  

ERIC Educational Resources Information Center

|Used Monte Carlo simulation to examine the performance of four missing data methods in structural equation models: (1)full information maximum likelihood (FIML); (2) listwise deletion; (3) pairwise deletion; and (4) similar response pattern imputation. Results show that FIML estimation is superior across all conditions of the design. (SLD)|

Enders, Craig K.; Bandalos, Deborah L.

2001-01-01

234

Level-Specific Evaluation of Model Fit in Multilevel Structural Equation Modeling  

ERIC Educational Resources Information Center

In multilevel structural equation modeling, the "standard" approach to evaluating the goodness of model fit has a potential limitation in detecting the lack of fit at the higher level. Level-specific model fit evaluation can address this limitation and is more informative in locating the source of lack of model fit. We proposed level-specific test…

Ryu, Ehri; West, Stephen G.

2009-01-01

235

An Illustration of a Longitudinal Cross-Lagged Design for Larger Structural Equation Models. Teacher's Corner.  

ERIC Educational Resources Information Center

|Tested a model of HIV behavior risk, using a fully cross-lagged, longitudinal design to illustrate the analysis of larger structural equation models. Data from 527 women who completed a survey at three time points show excellent fit of the model to the data. (SLD)|

Burkholder, Gary J.; Harlow, Lisa L.

2003-01-01

236

Spiritual Leadership and Organizational Culture: A Study of Structural Equation Modeling  

ERIC Educational Resources Information Center

The aim of this study is to test the spiritual leadership behaviors of school principles in a structural equation model. The study is designed to test causality with the assumption that causality exists between the two variables. In this study, spiritual leadership behavior of managers is treated as the independent variable whereas the…

Karadag, Engin

2009-01-01

237

Use of structural equation modeling in operations management research: Looking back and forward  

Microsoft Academic Search

This paper reviews applications of structural equation modeling (SEM) in four major Operations Management journals (Management Science, Journal of Operations Management, Decision Sciences, and Journal of Production and Operations Management Society) and provides guidelines for improving the use of SEM in operations management (OM) research. We review 93 articles from the earliest application of SEM in these journals in 1984

Rachna Shah; Susan Meyer Goldstein

2006-01-01

238

The creative environment's influence on intent to turnover : A structural equation model and analysis  

Microsoft Academic Search

Purpose – This paper aims to examine the creative environment's effect on a worker's intent to turnover. It was designed to investigate the creative environment's role on garden variety creativity (non-elite) workers' organizational outcomes. Design\\/methodology\\/approach – A survey was used to collect data from a heterogeneous sample of garden variety creativity workers. This data was analyzed using a structural equation

Jacqueline Mayfield; Milton Mayfield

2008-01-01

239

Estimation of health effects of prenatal methylmercury exposure using structural equation models  

Microsoft Academic Search

BACKGROUND: Observational studies in epidemiology always involve concerns regarding validity, especially measurement error, confounding, missing data, and other problems that may affect the study outcomes. Widely used standard statistical techniques, such as multiple regression analysis, may to some extent adjust for these shortcomings. However, structural equations may incorporate most of these considerations, thereby providing overall adjusted estimations of associations. This

Esben Budtz-Jørgensen; Niels Keiding; Philippe Grandjean; Pal Weihe

2002-01-01

240

Residuals and the Residual-Based Statistic for Testing Goodness of Fit of Structural Equation Models  

ERIC Educational Resources Information Center

|The residuals obtained from fitting a structural equation model are crucial ingredients in obtaining chi-square goodness-of-fit statistics for the model. The authors present a didactic discussion of the residuals, obtaining a geometrical interpretation by recognizing the residuals as the result of oblique projections. This sheds light on the…

Foldnes, Njal; Foss, Tron; Olsson, Ulf Henning

2012-01-01

241

Bayesian Structural Equation Modeling: A More Flexible Representation of Substantive Theory  

ERIC Educational Resources Information Center

|This article proposes a new approach to factor analysis and structural equation modeling using Bayesian analysis. The new approach replaces parameter specifications of exact zeros with approximate zeros based on informative, small-variance priors. It is argued that this produces an analysis that better reflects substantive theories. The proposed…

Muthen, Bengt; Asparouhov, Tihomir

2012-01-01

242

Multilevel Modeling of Two Cyclical Processes: Extending Differential Structural Equation Modeling to Nonlinear Coupled Systems  

Microsoft Academic Search

The authors present a dynamical multilevel model that captures changes over time in the bidirectional, potentially asymmetric influence of 2 cyclical processes. S. M. Boker and J. Graham's (1998) differential structural equation modeling approach was expanded to the case of a nonlinear coupled oscillator that is common in bimanual coordination studies in which participants swing hand-held pendulums but is also

Jonathan Butner; Polemnia G. Amazeen; Genna M. Mulvey

2005-01-01

243

Meta-Analytic Structural Equation Modeling: A Two-Stage Approach  

ERIC Educational Resources Information Center

To synthesize studies that use structural equation modeling (SEM), researchers usually use Pearson correlations (univariate r), Fisher z scores (univariate z), or generalized least squares (GLS) to combine the correlation matrices. The pooled correlation matrix is then analyzed by the use of SEM. Questionable inferences may occur for these ad hoc…

Cheung, Mike W. L.; Chan, Wai

2005-01-01

244

On Insensitivity of the Chi-Square Model Test to Nonlinear Misspecification in Structural Equation Models  

ERIC Educational Resources Information Center

|In this paper, we show that for some structural equation models (SEM), the classical chi-square goodness-of-fit test is unable to detect the presence of nonlinear terms in the model. As an example, we consider a regression model with latent variables and interactions terms. Not only the model test has zero power against that type of…

Mooijaart, Ab; Satorra, Albert

2009-01-01

245

A Confirmatory Structural Equation Model of Achievement Estimated by Dichotomous Attitudes, Interest, and Conceptual Understanding  

ERIC Educational Resources Information Center

|Many models in science education have tried to clarify the causal relationships of affective variables on student performance, by presenting theoretical models, exploratory SEM (structural equation models), and confirmatory SEM. Based on the literature, the recent AS-TI-CU model scrutinised the most robust stimuli of conceptual understanding…

Kim, Minkee; Song, Jinwoong

2010-01-01

246

Relationships among Adolescents' Leisure Motivation, Leisure Involvement, and Leisure Satisfaction: A Structural Equation Model  

ERIC Educational Resources Information Center

The purpose of this cross-sectional study was to test a cause-and-effect model of factors affecting leisure satisfaction among Taiwanese adolescents. A structural equation model was proposed in which the relationships among leisure motivation, leisure involvement, and leisure satisfaction were explored. The study collected data from 701 adolescent…

Chen, Ying-Chieh; Li, Ren-Hau; Chen, Sheng-Hwang

2013-01-01

247

Estimation of reliability and validity of agility constructs using structural equation modelling  

Microsoft Academic Search

The main objective of this study was to create an agile manufacturing (AM) model and to validate the model using structural equation modelling (SEM). AM concentrates on turbulent market changes and the responsive actions of the manufacturing firm, in terms of process, tooling, material and trained experts. The AM model consists of five major drivers of agility, namely the workforce,

S. Vinodh; S. Aravindraj; Bala Pushkar; Sanjay Kishore

2011-01-01

248

Bayesian Structural Equation Modeling: A More Flexible Representation of Substantive Theory  

ERIC Educational Resources Information Center

This article proposes a new approach to factor analysis and structural equation modeling using Bayesian analysis. The new approach replaces parameter specifications of exact zeros with approximate zeros based on informative, small-variance priors. It is argued that this produces an analysis that better reflects substantive theories. The proposed…

Muthen, Bengt; Asparouhov, Tihomir

2012-01-01

249

Anti-Transgender Prejudice: A Structural Equation Model of Associated Constructs  

ERIC Educational Resources Information Center

|This study aimed to identify theoretically relevant key correlates of anti-transgender prejudice. Specifically, structural equation modeling was used to test the unique relations of anti-lesbian, gay, and bisexual (LGB) prejudice; traditional gender role attitudes; need for closure; and social dominance orientation with anti-transgender…

Tebbe, Esther N.; Moradi, Bonnie

2012-01-01

250

A Program Implementing Mardia's Multivariate Normality Test for Use in Structural Equation Modeling with Latent Variables.  

ERIC Educational Resources Information Center

|Presents KANT, a FORTRAN 77 software program that tests assumptions of multivariate normality in a data set. Based on the test developed by M. V. Mardia (1985), the KANT program is useful for those engaged in structural equation modeling with latent variables. (SLD)|

MacIntosh, Randall

1997-01-01

251

(Why) Should We Use SEM? Pros and Cons of Structural Equation Modeling  

Microsoft Academic Search

During the last two decades, Structural Equation Modeling (SEM) has evolved from a statistical technique for insiders to an established valuable tool for a broad scientific public. This class of analyses has much to offer, but at what price? This paper pro- vides an overview on SEM, its underlying ideas, potential applications and current software. Furthermore, it discusses avoidable pitfalls

Christof Nachtigall; Ulf Kroehne; Friedrich Funke; Rolf Steyer

252

Performance and scaling of locally-structured grid methods for partial differential equations  

Microsoft Academic Search

In this paper, we discuss some of the issues in obtaining high performance for block-structured adaptive mesh refinement software for partial differential equations. We show examples in which AMR scales to thousands of processors. We also discuss a number of metrics for performance and scalability that can provide a basis for understanding the advantages and disadvantages of this approach.

Phillip Colella; John Bell; Noel Keen; Terry Ligocki; Michael Lijewski; Brian van Straalen

2007-01-01

253

Bayesian Structural Equation Modeling: A More Flexible Representation of Substantive Theory  

Microsoft Academic Search

This article proposes a new approach to factor analysis and structural equation modeling using Bayesian analysis. The new approach replaces parameter specifications of exact zeros with approximate zeros based on informative, small-variance priors. It is argued that this produces an analysis that better reflects substantive theories. The proposed Bayesian approach is particularly beneficial in applications where parameters are added to

Bengt Muthén; Tihomir Asparouhov

2012-01-01

254

An Exploratory Analysis of Women's Empowerment in India: A Structural Equation Modelling Approach  

Microsoft Academic Search

The study is an exercise to explore possible directions of causation of level of women's empowerment, a latent variable, with related factors with the view to identify the causes of slow growth of it in India applying the ‘Structural Equation Modelling' (SEM) method to Third National Family and Health Survey data conducted during 2005–2006. The results recognise the inefficiency of

Snigdha Chakrabarti; Chaiti Sharmab Biswas

2012-01-01

255

Quasi-Maximum Likelihood Estimation of Structural Equation Models with Multiple Interaction and Quadratic Effects  

ERIC Educational Resources Information Center

|In this article, a nonlinear structural equation model is introduced and a quasi-maximum likelihood method for simultaneous estimation and testing of multiple nonlinear effects is developed. The focus of the new methodology lies on efficiency, robustness, and computational practicability. Monte-Carlo studies indicate that the method is highly…

Klein, Andreas G.; Muthen, Bengt O.

2007-01-01

256

Understanding the Impact of Trauma Exposure on Posttraumatic Stress Symptomatology: A Structural Equation Modeling Approach  

ERIC Educational Resources Information Center

|The objective of this study was to investigate the impact of trauma exposure on the posttraumatic stress symptomatology (PTSS) of children who resided near the epicenter of the 2008 Wenchuan earthquake. The mechanisms of this impact were explored via structural equation models with self-esteem and coping strategies included as mediators. The…

Chen, Wei; Wang, Long; Zhang, Xing-Li; Shi, Jian-Nong

2012-01-01

257

Structural Equation Models for Interchangeable Dyads: Being the Same Makes a Difference  

ERIC Educational Resources Information Center

|Structural equation modeling (SEM) offers a flexible method for studying the patterns of interdependence in partners' behavior, which lie at the heart of interactions and relationships. Although SEM has been applied to the study of distinguishable dyads, in which partners are distinguishable by type, such as male and female, it has rarely been…

Woody, Erik; Sadler, Pamela

2005-01-01

258

12?Structural Equation Modeling in Management Research: A Guide for Improved Analysis  

Microsoft Academic Search

A large segment of management research in recent years has used structural equation modeling (SEM) as an analytical approach that simultaneously combines factor analysis and linear regression models for theory testing. With this approach, latent variables (factors) represent the concepts of a theory, and data from measures (indicators) are used as input for statistical analyses that provide evidence about the

Larry J. Williams; Robert J. Vandenberg; Jeffrey R. Edwards

2009-01-01

259

A strategic analysis for successful Brain Korea 21 initiative based on structural equation model  

Microsoft Academic Search

Brain Korea 21 (BK21) is a plan launched by the Korea Ministry of Education to strengthen the competitiveness of research and education quality of universities in Korea. The main objective of this study is to evaluate BK21 initiative and provide feedback for more effective implementation. We used a structural equation models to find the relationship among various factors with the

So Young Sohn; Hyoung Ki So; Tae Hee Moon

2009-01-01

260

A Robust Bayesian Approach for Structural Equation Models with Missing Data  

ERIC Educational Resources Information Center

In this paper, normal/independent distributions, including but not limited to the multivariate t distribution, the multivariate contaminated distribution, and the multivariate slash distribution, are used to develop a robust Bayesian approach for analyzing structural equation models with complete or missing data. In the context of a nonlinear…

Lee, Sik-Yum; Xia, Ye-Mao

2008-01-01

261

Equivalence and Differences between Structural Equation Modeling and State-Space Modeling Techniques  

ERIC Educational Resources Information Center

|State-space modeling techniques have been compared to structural equation modeling (SEM) techniques in various contexts but their unique strengths have often been overshadowed by their similarities to SEM. In this article, we provide a comprehensive discussion of these 2 approaches' similarities and differences through analytic comparisons and…

Chow, Sy-Miin; Ho, Moon-ho R.; Hamaker, Ellen L.; Dolan, Conor V.

2010-01-01

262

Evaluating Small Sample Approaches for Model Test Statistics in Structural Equation Modeling.  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) attempts to remove the negative influence of measurement error and allows for investigation of relationships at the level of the underlying constructs of interest. SEM has been regarded as a "large sample" technique since its inception. Recent developments in SEM, some of which are currently available in popular…

Nevitt, Jonathan

263

Evaluating Small Sample Approaches for Model Test Statistics in Structural Equation Modeling  

ERIC Educational Resources Information Center

Through Monte Carlo simulation, small sample methods for evaluating overall data-model fit in structural equation modeling were explored. Type I error behavior and power were examined using maximum likelihood (ML), Satorra-Bentler scaled and adjusted (SB; Satorra & Bentler, 1988, 1994), residual-based (Browne, 1984), and asymptotically…

Nevitt, Jonathan; Hancock, Gregory R.

2004-01-01

264

Early Stage Breast Cancer: Explaining Level of Psychosocial Adjustment Using Structural Equation Modeling  

Microsoft Academic Search

In many women, the diagnosis of breast cancer leads to psychosocial adjustment problems. Biodemographic variables, coping, and social support are factors that influence psychosocial adjustment. The main objective of the present study was to identify and estimate the associations between psychosocial adjustment and biodemographic variables, coping, and social support by using Structural Equation Modeling (SEM). Eighty-seven women with newly diagnosed

Petra J. Vos; Bert Garssen; Adriaan P. Visser; Hugo J. Duivenvoorden

2004-01-01

265

A Robust Bayesian Approach for Structural Equation Models with Missing Data  

ERIC Educational Resources Information Center

|In this paper, normal/independent distributions, including but not limited to the multivariate t distribution, the multivariate contaminated distribution, and the multivariate slash distribution, are used to develop a robust Bayesian approach for analyzing structural equation models with complete or missing data. In the context of a nonlinear…

Lee, Sik-Yum; Xia, Ye-Mao

2008-01-01

266

Bias and Efficiency in Structural Equation Modeling: Maximum Likelihood versus Robust Methods  

ERIC Educational Resources Information Center

|In the structural equation modeling literature, the normal-distribution-based maximum likelihood (ML) method is most widely used, partly because the resulting estimator is claimed to be asymptotically unbiased and most efficient. However, this may not hold when data deviate from normal distribution. Outlying cases or nonnormally distributed data,…

Zhong, Xiaoling; Yuan, Ke-Hai

2011-01-01

267

A Structural Equation Modeling Evaluation of the General Model of Instructional Communication  

Microsoft Academic Search

The General Model of Instructional Communication introduced by McCroskey, Valencic, and Richmond (2004) is supported in its original conception by canonical data. This study, however, uses structural equation modeling (SEM) to provide a more detailed analysis. Although the model as originally hypothesized fits the data poorly, analysis of the SEM results suggests adjustments to the original model that substantially improve

James A. Katt; James C. McCroskey; Stephen A. Sivo; Virginia P. Richmond; Kristin M. Valencic

2009-01-01

268

Relationships among Adolescents' Leisure Motivation, Leisure Involvement, and Leisure Satisfaction: A Structural Equation Model  

ERIC Educational Resources Information Center

|The purpose of this cross-sectional study was to test a cause-and-effect model of factors affecting leisure satisfaction among Taiwanese adolescents. A structural equation model was proposed in which the relationships among leisure motivation, leisure involvement, and leisure satisfaction were explored. The study collected data from 701…

Chen, Ying-Chieh; Li, Ren-Hau; Chen, Sheng-Hwang

2013-01-01

269

Strategies for revitalization for intelligent robot industry in Korea based on structural equation model  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the effect of the government's role in boosting the utilization of intelligent robot by considering government support policies along with various other factors, which are potentially influential. This type of investigation will contribute for developing a domestic robot infrastructure in Korea. Design\\/methodology\\/approach – A structural equation model is used to

So Young Sohn; Man Jae Kim

2010-01-01

270

Performance and scaling of locally-structured grid methods forpartial differential equations  

SciTech Connect

In this paper, we discuss some of the issues in obtaining high performance for block-structured adaptive mesh refinement software for partial differential equations. We show examples in which AMR scales to thousands of processors. We also discuss a number of metrics for performance and scalability that can provide a basis for understanding the advantages and disadvantages of this approach.

Colella, Phillip; Bell, John; Keen, Noel; Ligocki, Terry; Lijewski, Michael; Van Straalen, Brian

2007-07-19

271

Predicting Chinese young consumers’ acceptance of mobile advertising: a structural equation modeling approach  

Microsoft Academic Search

A survey of Chinese college students was conducted in May and June 2009 to test a model of mobile advertising developed by Merisavo and associates in 2007 in which five factors (utility, context, control, sacrifice, and trust) predict consumer acceptance of mobile advertising. A structural equation modeling was employed to fit the model to survey data from 422 completed usable

Hongwei Yang; Hui Liu; Liuning Zhou

2010-01-01

272

Quasi-Maximum Likelihood Estimation of Structural Equation Models With Multiple Interaction and Quadratic Effects  

Microsoft Academic Search

In this article, a nonlinear structural equation model is introduced and a quasi-maximum likelihood method for simultaneous estimation and testing of multiple nonlinear effects is developed. The focus of the new methodology lies on efficiency, robustness, and computational practicability. Monte-Carlo studies indicate that the method is highly efficient and that the likelihood ratio test of nonlinear effects is robust and

Andreas G. Klein; Bengt O. Muthén

2007-01-01

273

IQ heritability estimation: Analyzing genetically-informative data with structural equation models  

Microsoft Academic Search

When analyzing genetic data, Structural Equations Modeling (SEM) provides a straightforward me- thodology to decompose phenotypic variance using a model-based approach. Furthermore, several mo- dels can be easily implemented, tested, and compared using SEM, allowing the researcher to obtain va- luable information about the sources of variability. This methodology is briefly described and applied to re-analyze a Spanish set of

David Gallardo Pujol; Carlos García-Forero; Uwe Kramp; Albert Maydeu-Olivares; Antonio Andrés-Pueyo

2007-01-01

274

Bayesian analysis of multi-group nonlinear structural equation models with application to behavioral finance  

Microsoft Academic Search

Structural equation models (SEMs) have been widely used to determine the relationships among certain observed and latent variables in behavioral finance. The purpose of this paper is to develop a Bayesian approach for analysing multi-group nonlinear SEMs. Using recently developed tools in statistical computing, such as the Gibbs sampler, we propose an efficient method to estimate parameters and select an

Bin Lu; Xin-Yuan Song; Xin-Dan Li

2012-01-01

275

A Monte Carlo Study of Structural Equation Models for Finite Mixtures  

Microsoft Academic Search

Empirical applications of structural equation modeling (SEM) typically rest on the assumption that the analysed sample is homogenous with respect to the underlying struc- tural model or that homogenous subsamples have been formed based on a priori knowl- edge. However, researchers often are ignorant about the true causes of heterogeneity and thus risk to produce misleading results. Using a sequential

John Williams; Dirk Temme; Lutz Hildebrandt

2002-01-01

276

Linking structural equation modeling to Bayesian networks: Decision support for customer retention in virtual communities  

Microsoft Academic Search

Bayesian networks are limited in differentiating between causal and spurious relationships among decision factors. Decision making without differentiating the two relationships cannot be effective. To overcome this limitation of Bayesian networks, this study proposes linking Bayesian networks to structural equation modeling (SEM), which has an advantage in testing causal relationships between factors. The capability of SEM in empirical validation combined

Sumeet Gupta; Hee-woong Kim

2008-01-01

277

A spatial structural equation model with an application to area health needs  

Microsoft Academic Search

Indices of population ‘health need’ are often used to distribute health resources or assess equity in service provision. This article describes a spatial structural equation model incorporating multiple indicators of need and multiple population health risks that affect need (analogous to multiple indicators–multiple causes models). More specifically, the multiple indicator component of the model involves health outcomes such as hospital

Peter Congdon

2010-01-01

278

Bayesian analysis of multi-group nonlinear structural equation models with application to behavioral finance  

Microsoft Academic Search

Structural equation models (SEMs) have been widely used to determine the relationships among certain observed and latent variables in behavioral finance. The purpose of this paper is to develop a Bayesian approach for analysing multi-group nonlinear SEMs. Using recently developed tools in statistical computing, such as the Gibbs sampler, we propose an efficient method to estimate parameters and select an

Bin Lu; Xin-Yuan Song; Xin-Dan Li

2010-01-01

279

A Comparison of Methods for Estimating Quadratic Effects in Nonlinear Structural Equation Models  

Microsoft Academic Search

Two Monte Carlo simulations were performed to compare methods for estimating and testing hypotheses of quadratic effects in latent variable regression models. The methods considered in the current study were (a) a 2-stage moderated regression approach using latent variable scores, (b) an unconstrained product indicator approach, (c) a latent moderated structural equation method, (d) a fully Bayesian approach, and (e)

Jeffrey R. Harring; Brandi A. Weiss; Jui-Chen Hsu

2012-01-01

280

Analysis of structural equation models with exact and stochastic constraints using a bayesian approach  

Microsoft Academic Search

In this paper, multisample analyses of exactand stochastic constraints with identified structural equation models are investigated using a Bayesian approach. Asymptotic properties of the estimates are developed and a multiplier method is employed to obtain the solution. A numerical example is also included as an illustration.

Wai-Tung Ho; Sik-Yum Lee

1993-01-01

281

Bayesian Methods for Analyzing Structural Equation Models With Covariates, Interaction, and Quadratic Latent Variables  

Microsoft Academic Search

The analysis of interaction among latent variables has received much attention. This article introduces a Bayesian approach to analyze a general structural equation model that accommodates the general nonlinear terms of latent variables and covariates. This approach produces a Bayesian estimate that has the same statistical optimal properties as a maximum likelihood estimate. Other advantages over the traditional approaches are

Sik-Yum Lee; Xin-Yuan Song; Nian-Sheng Tang

2007-01-01

282

Exact Solutions and Coherence Structures of Generalized Breor-Kaup Equations  

NASA Astrophysics Data System (ADS)

Using the mapping method based on q-deformed hyperbolic functions, the exact solutions of generalized Breor-Kaup equations are obtained. Based on the solutions, two coherent structures, periodic-branch kink and non-propagating kink, have been obtained. Moreover, one solitonal interaction form, two line solitons interaction on the kink background, has been found.

Zheng, Qiang; Zhang, Xiao-Ping; Ren, Zhong-Zhou

2008-12-01

283

Standards-Based Evaluation and Teacher Career Satisfaction: A Structural Equation Modeling Analysis  

Microsoft Academic Search

Structural equation modeling was used to assess the plausibility of a conceptual model specifying hypothesized linkages among perceptions of characteristics of standards-based evaluation, work environment mediators, and career satisfaction and other outcomes. Four comprehensive high schools located in two neighboring counties in southern California provided the data for this study. The schools’ districts had recently developed and implemented evaluation systems

Sharon Conley; Donna E. Muncey; Sukkyung You

2005-01-01

284

Mx Scripts Library: Structural Equation Modeling Scripts for Twin and Family Data  

Microsoft Academic Search

Structural equation modeling (SEM) provides a flexible tool to carry out genetic analyses of family and twin data. The basic model which decomposes the variance between and within families for a particular trait into genetic and non-genetic components can be generalized to multivariate and\\/ or longitudinal data, incorporate sex differences in parameter estimates, and model the effects of measured environment,

D. Posthuma; D. I. Boomsma

2005-01-01

285

The Impact of Specification Error on the Estimation, Testing, and Improvement of Structural Equation Models.  

ERIC Educational Resources Information Center

|The impact of misspecification on the estimation, testing, and improvement of structural equation models was assessed via a population study in which a prototypical latent variable model was misspecified. Results provide insights into the maximum likelihood estimator versus a limited two-stage least squares estimator in LISREL. (TJH)|

Kaplan, David

1988-01-01

286

Teacher's Corner: Structural Equation Modeling with the Sem Package in R  

ERIC Educational Resources Information Center

|R is free, open-source, cooperatively developed software that implements the S statistical programming language and computing environment. The current capabilities of R are extensive, and it is in wide use, especially among statisticians. The sem package provides basic structural equation modeling facilities in R, including the ability to fit…

Fox, John

2006-01-01

287

University Students' Behaviors Pertaining to Sustainability: A Structural Equation Model with Sustainability-Related Attributes  

ERIC Educational Resources Information Center

|The purpose of this study is to construct a structural equation model to examine the links among attitudes, values, and behaviors pertaining to sustainability, participation in outdoor recreation as well as gender and tendency to follow mass media for university students. The data were collected by on-line administration of a survey to 958…

Sahin, Elvan; Ertepinar, Hamide; Teksoz, Gaye

2012-01-01

288

The Relation among Fit Indexes, Power, and Sample Size in Structural Equation Modeling  

ERIC Educational Resources Information Center

|The relation among fit indexes, power, and sample size in structural equation modeling is examined. The noncentrality parameter is required to compute power. The 2 existing methods of computing power have estimated the noncentrality parameter by specifying an alternative hypothesis or alternative fit. These methods cannot be implemented easily…

Kim, Kevin H.

2005-01-01

289

Maternal feeding strategies and child's food intake: considering weight and demographic influences using structural equation modeling  

Microsoft Academic Search

BACKGROUND: Research concerning child's food intake have considered various influencing factors, for example parental feeding strategies, demographic and weight factors. At this time, however, there are few findings that explore these factors simultaneously. Accordingly, the aim of this study was to test a structural equation model regarding the associations between maternal feeding strategies and child's food intake. METHODS: 556 mothers

Katja Kröller; Petra Warschburger

2009-01-01

290

Does Method of Handling Missing Data Affect Results of a Structural Equation Model?  

ERIC Educational Resources Information Center

|The influence of method of handling missing data on estimates produced by a structural equation model of the effects of part-time work on high-school student achievement was investigated. Missing data methods studied were listwise deletion, pairwise deletion, the expectation maximization (EM) algorithm, regression, and response pattern. The 26…

Witta, E. Lea

291

A Demonstration of a Systematic Item-Reduction Approach Using Structural Equation Modeling  

ERIC Educational Resources Information Center

|Establishing model parsimony is an important component of structural equation modeling (SEM). Unfortunately, little attention has been given to developing systematic procedures to accomplish this goal. To this end, the current study introduces an innovative application of the jackknife approach first presented in Rensvold and Cheung (1999).…

Larwin, Karen; Harvey, Milton

2012-01-01

292

A Structural Equation Model of the Factors Influencing British Consumers’ Behaviour towards Animal Welfare  

Microsoft Academic Search

Results of national and pan-European consumer surveys and the growth in the demand for so-called “animal friendly” food products suggest that consumers within the European Union show a high level of concern for the welfare of farm animals. This paper analyses the determinants of British consumers’ behaviour towards animal welfare using structural equation models (SEM) with observed and latent variables.

Luiza Toma; Alistair McVittie; Carmen Hubbard; Alistair W. Stott

2009-01-01

293

Quasi-Maximum Likelihood Estimation of Structural Equation Models with Multiple Interaction and Quadratic Effects  

ERIC Educational Resources Information Center

In this article, a nonlinear structural equation model is introduced and a quasi-maximum likelihood method for simultaneous estimation and testing of multiple nonlinear effects is developed. The focus of the new methodology lies on efficiency, robustness, and computational practicability. Monte-Carlo studies indicate that the method is highly…

Klein, Andreas G.; Muthen, Bengt O.

2007-01-01

294

Bayesian Analysis of Nonlinear Structural Equation Models with Nonignorable Missing Data  

Microsoft Academic Search

A Bayesian approach is developed for analyzing nonlinear structural equation models with nonignorable missing data. The nonignorable\\u000a missingness mechanism is specified by a logistic regression model. A hybrid algorithm that combines the Gibbs sampler and\\u000a the Metropolis–Hastings algorithm is used to produce the joint Bayesian estimates of structural parameters, latent variables,\\u000a parameters in the nonignorable missing model, as well as

Sik-Yum Lee; NIAN-SHENG TANG

2006-01-01

295

Fitting Data to Model: Structural Equation Modeling Diagnosis Using Two Scatter Plots  

Microsoft Academic Search

This article introduces two simple scatter plots for model diagnosis in structural equation modeling. One plot contrasts a residual-based M-distance of the structural model with the M-distance for the factor score. It contains information on outliers, good leverage observations, bad leverage observations, and normal cases. The other plot contrasts the residual-based M-distance with the quantile of a chi distribution. It

Ke-Hai Yuan; Kentaro Hayashi

2010-01-01

296

Maximum Likelihood Analysis of a Two-Level Nonlinear Structural Equation Model With Fixed Covariates  

Microsoft Academic Search

In this article, a maximum likelihood (ML) approach for analyzing a rather general two-level structural equation model is developed for hierarchically structured data that are very common in educational and\\/or behavioral research. The proposed two-level model can accommodate nonlinear causal relations among latent variables as well as effects of fixed covariate in its various components. Methods for computing the ML

Sik-Yum Lee; Xin-Yuan Song

2005-01-01

297

Environmental behavior structure and socio-economic conditions of hillside farmers: A multiple-group structural equation modeling approach  

Microsoft Academic Search

Using structural equation modeling and a health belief model within a conceptual economic framework, we examined the effects of perceived susceptibility, severity, benefits, and barriers on farmers' awareness of and attitudes towards environmental degradation. Perception of the severity of land degradation had a positive effect on individuals' awareness and attitude, regardless of socio-economic status. Farmers' perceived susceptibility to land degradation

Budry Bayard; Curtis Jolly

2007-01-01

298

Examining the Factor Structure and Discriminant Validity of the 12-Item General Health Questionnaire (GHQ-12) Among Spanish Postpartum Women  

ERIC Educational Resources Information Center

|In this study, the authors tested alternative factor models of the 12-item General Health Questionnaire (GHQ-12) in a sample of Spanish postpartum women, using confirmatory factor analysis. The authors report the results of modeling three different methods for scoring the GHQ-12 using estimation methods recommended for categorical and binary…

Aguado, Jaume; Campbell, Alistair; Ascaso, Carlos; Navarro, Purificacion; Garcia-Esteve, Lluisa; Luciano, Juan V.

2012-01-01

299

The schema questionnaire: Investigation of psychometric properties and the hierarchical structure of a measure of maladaptive schemas  

Microsoft Academic Search

Although schemas play a central role in cognitive conceptualizations of personality disorders, research devoted to the assessment of schemas has been scarce. This article describes the preliminary validation of a measure of schemas relevant to personality disorders. The Schema Questionnaire (SQ) was developed using five independent samples (N=1,564). In study 1, factor analyses using a student sample revealed 13 primary

Norman B. Schmidt; Thomas E. Joiner; Jeffery E. Young; Michael J. Telch

1995-01-01

300

Measuring physical activity among pregnant women using a structured one-week recall questionnaire: evidence for validity and reliability  

Microsoft Academic Search

BACKGROUND: Accurate measurement of the components of physical activity during pregnancy can aid in our understanding of the dose response relationships between physical activity and corresponding perinatal outcomes. The aim of this study was to develop and evaluate a one-week recall questionnaire to assess moderate to vigorous physical activity during pregnancy. METHODS: To assess concurrent-related validity, 177 pregnant women (median

Kelly R Evenson; Fang Wen

2010-01-01

301

Symplectic structure of wave-equation imaging: a path-integral approach based on the double-square-root equation  

NASA Astrophysics Data System (ADS)

We carry out high-frequency analyses of Claerbout's double-square-root equation and its (numerical) solution procedures in heterogeneous media. We show that the double-square-root equation generates the adjoint of the single-scattering modelling operator upon substituting the leading term of the generalized Bremmer series for the background Green function. This adjoint operator yields the process of `wave-equation' imaging. We finally decompose the wave-equation imaging process into common image point gathers in accordance with the characteristic strips in the wavefront set of the data.

de Hoop, Maarten V.; Le Rousseau, Jérôme H.; Biondi, Biondo L.

2003-04-01

302

Kane's equations of flexible multibody systems with tree structure - A computer-oriented modeling approach  

NASA Astrophysics Data System (ADS)

Kane's dynamical model of flexible multibody space systems with tree structure is developed in this paper. The system topology is restricted to a tree configuration which is defined as an arbitrary set of flexible and rigid bodies connected by hinges characterizing relative translations and rotations of two adjoining bodies. The relative translational velocities, angular velocities, and the differential of model coordinates are selected as the generalized velocities. The motion equations of minimum dimension are derived via Kane's method. The resulting equations are suitable for automatic generation and computer simulation.

Jin, Liang; Bauer, Helmut F.

1991-09-01

303

Enriched behavioral prediction equation and its impact on structured leaning and the dynamic calculus.  

PubMed

This theoretical note describes an expansion of the behavioral prediction equation, in line with the greater complexity encountered in models of structured learning theory (R. B. Cattell, 1996a). This presents learning theory with a vector substitute for the simpler scalar quantities by which traditional Pavlovian-Skinnerian models have hitherto been represented. Structured learning can be demonstrated by vector changes across a range of intrapersonal psychological variables (ability, personality, motivation, and state constructs). Its use with motivational dynamic trait measures (R. B. Cattell, 1985) should reveal new theoretical possibilities for scientifically monitoring change processes (dynamic calculus model: R. B. Cattell, 1996b), such as encountered within psychotherapeutic settings (R. B. Cattell, 1987). The enhanced behavioral prediction equation suggests that static conceptualizations of personality structure such as the Big Five model are less than optimal. PMID:11863038

Cattell, Raymond B; Boyle, Gregory J; Chant, David

2002-01-01

304

Self-assembly of nanocomponents into composite structures: Derivation and simulation of Langevin equations  

NASA Astrophysics Data System (ADS)

The kinetics of the self-assembly of nanocomponents into a virus, nanocapsule, or other composite structure is analyzed via a multiscale approach. The objective is to achieve predictability and to preserve key atomic-scale features that underlie the formation and stability of the composite structures. We start with an all-atom description, the Liouville equation, and the order parameters characterizing nanoscale features of the system. An equation of Smoluchowski type for the stochastic dynamics of the order parameters is derived from the Liouville equation via a multiscale perturbation technique. The self-assembly of composite structures from nanocomponents with internal atomic structure is analyzed and growth rates are derived. Applications include the assembly of a viral capsid from capsomers, a ribosome from its major subunits, and composite materials from fibers and nanoparticles. Our approach overcomes errors in other coarse-graining methods, which neglect the influence of the nanoscale configuration on the atomistic fluctuations. We account for the effect of order parameters on the statistics of the atomistic fluctuations, which contribute to the entropic and average forces driving order parameter evolution. This approach enables an efficient algorithm for computer simulation of self-assembly, whereas other methods severely limit the timestep due to the separation of diffusional and complexing characteristic times. Given that our approach does not require recalibration with each new application, it provides a way to estimate assembly rates and thereby facilitate the discovery of self-assembly pathways and kinetic dead-end structures.

Pankavich, S.; Shreif, Z.; Miao, Y.; Ortoleva, P.

2009-05-01

305

Psychometric Properties of the Trait Emotional Intelligence Questionnaire: Factor Structure, Reliability, Construct, and Incremental Validity in a French-Speaking Population  

Microsoft Academic Search

In this research, we investigated the psychometrical properties of the Trait Emotional Intelligence Questionnaire (TEIQue, Petrides & Furnham, 2003) in a French-speaking population. In summary, we found that (a) TEIQue scores were globally normally distributed and reliable; (b) the United Kingdom four-factor structure (well-being, self-control, emotionality, sociability) replicated in our data; (c) TEIQue scores were dependent on gender but relatively

Olivier Luminet; Cecile Leroy; Emmanuel Roy

2007-01-01

306

Measuring exposure to bullying and harassment at work: Validity, factor structure and psychometric properties of the Negative Acts Questionnaire-Revised  

Microsoft Academic Search

This study investigates the psychometric properties, factor structure and validity of the revised Negative Acts Questionnaire-Revised (NAQ-R), an instrument designed to measure exposure to bullying in the workplace. By reanalyzing data based on a heterogeneous sample of 5288 UK employees, the results show that the 22-item instrument has a high internal stability, with three underlying factors: personal bullying, work-related bullying

Staale Einarsen; Helge Hoel; Guy Notelaers

2009-01-01

307

Cosmic energy equation for extended structures and its application to gravitational galaxy clustering  

NASA Astrophysics Data System (ADS)

Cosmic energy equation represents the law of conservation of energy in the region expanding with time as the universe expands. It gives the evolution of kinetic and correlation potential energy with time in a cluster expanding as the universe expands. To understand the clustering of galaxies under the influence of gravitational force, cosmic energy equation is of great help. We use cosmic energy equation for extended structures (galaxies with halos) to analyse the gravitational galaxy clustering in different ways. We try to understand the influence of expansion on the clustering by deriving the relation between correlation parameter b V and scale factor R. We also derive the relation between the peculiar kinetic energy K and correlation parameter to know that when peculiar kinetic energy dominates over the kinetic energy of galaxies due to expansion. Besides, the evolution of specific heat and energy provides the information regarding the different states of clustering.

Wahid, Abdul; Ahmad, Ajaz

2012-10-01

308

General features and master equations for structurization in complex dusty plasmas  

SciTech Connect

Dust structurization is considered to be typical for complex plasmas. Homogeneous dusty plasmas are shown to be universally unstable. The dusty plasma structurization instability is similar to the gravitational instability and can results in creation of different compact dust structures. A general approach for investigation of the nonlinear stage of structurization in dusty plasmas is proposed and master equations for the description of self-organized structures are formulated in the general form that can be used for any nonlinear model of dust screening. New effects due to the scattering of ions on the nonlinearly screened grains are calculated: nonlinear ion dust drag force and nonlinear ion diffusion. The physics of confinement of dust and plasma components in the equilibria of compact dust structures is presented and is supported by numerical calculations of master equations. The necessary conditions for the existence of equilibrium structures are found for an arbitrary nonlinearity in dust screening. Features of compact dust structures observed in recent experiments agree with the numerically calculated ones. Some proposals for future experiments in spherical chamber are given.

Tsytovich, V. N., E-mail: tsytov@lpi.ru [Russian Academy of Science, General Physics Institute (Russian Federation); Morfill, G. E., E-mail: gem@mpe.mpg.de [Max Planck Institute for Extraterrestrial Physics (Germany)

2012-02-15

309

The Instruction set of Questionnaires can Affect the Structure of the Data: Application to Self-Rated State Anxiety  

Microsoft Academic Search

The present study tested the assumption that self-ratings, such as those used for measuring state anxiety, do not measure a one-dimensional transcendent entity but involve decisions based on a multi-dimensional judgment. Two groups of subjects were presented with a balanced nine-item state anxiety questionnaire. Each group received a different set of instructions (a standard set and an altered instruction set

Stéphane Vautier; Etienne Mullet; Sylvie Bourdet-loubère

2003-01-01

310

The Instruction set of Questionnaires can Affect the Structure of the Data: Application to Self-Rated State Anxiety  

Microsoft Academic Search

The present study tested the assumption that self-ratings, such as those used for measuring state anxiety, do not measure a one-dimensional tran- scendent entity but involve decisions based on a multi-dimensional judgment. Two groups ofsubjects were presented with a balanced nine-item state anxiety questionnaire. Each group received a different set of instructions (a standard set and an altered instruction set

Stéphane Vautier; Etienne Mullet; Sylvie Bourdet-loubère

2003-01-01

311

Can the job content questionnaire be used to assess structural and organizational properties of the work environment?  

Microsoft Academic Search

Objective  The theory behind the Job Content Questionnaire (JCQ) presumes that the “objective” social environment is measurable via self-report\\u000a inventories such as the JCQ. Hence, it is expected that workers in identical work will respond highly similar. However, since\\u000a no studies have evaluated this basic assumption, we decided to investigate whether workers performing highly similar work\\u000a also responded similarly to the

Roger PerssonAse; Åse Marie Hansen; Anne Helene Garde; Jesper Kristiansen; Catarina Nordander; Istvan Balogh; Kerstina Ohlsson; Per-Olof Östergren; Palle Ørbæk

312

Examining the influence of subjective norm and facilitating conditions on the intention to use technology among pre-service teachers: a structural equation modeling of an extended technology acceptance model  

Microsoft Academic Search

This study examined pre-service teachers’ self-reported behavioral intentions to use technology. Three hundred and fourteen\\u000a participants completed a survey questionnaire measuring their responses to six constructs from a research model that extends\\u000a the technology acceptance model (TAM) by including facilitating conditions and subjective norm. Structural equation modeling\\u000a was used as the main technique for data analysis. This study contributes to

Timothy Teo

2010-01-01

313

Trait Substitution Sequence process and Canonical Equation for age-structured populations.  

PubMed

We are interested in a stochastic model of trait and age-structured population undergoing mutation and selection. We start with a continuous time, discrete individual-centered population process. Taking the large population and rare mutations limits under a well-chosen time-scale separation condition, we obtain a jump process that generalizes the Trait Substitution Sequence process describing Adaptive Dynamics for populations without age structure. Under the additional assumption of small mutations, we derive an age-dependent ordinary differential equation that extends the Canonical Equation. These evolutionary approximations have never been introduced to our knowledge. They are based on ecological phenomena represented by PDEs that generalize the Gurtin-McCamy equation in Demography. Another particularity is that they involve an establishment probability, describing the probability of invasion of the resident population by the mutant one, that cannot always be computed explicitly. Examples illustrate how adding an age-structure enrich the modelling of structured population by including life history features such as senescence. In the cases considered, we establish the evolutionary approximations and study their long time behavior and the nature of their evolutionary singularities when computation is tractable. Numerical procedures and simulations are carried. PMID:18668245

Méléard, Sylvie; Tran, Viet Chi

2008-07-31

314

Bayesian nonlinear structural equation modeling for hierarchical validation of dynamical systems  

NASA Astrophysics Data System (ADS)

This paper presents a new Bayesian nonlinear structural equation modeling approach to hierarchical model assessment of dynamic systems, considering uncertainty in both predicted and measured time series data. A generalized structural equation modeling with nonlinear latent variables is presented to model two sets of relationships in multivariate hierarchical model assessment, namely, the computational model to system-level data, and low-level data to system-level data. A hierarchical Bayesian network with Markov Chain Monte Carlo simulation and Gibbs sampling is developed to represent the two relationships and estimate the influencing factors between them. A Bayesian interval hypothesis testing-based method is employed to quantify the confidence in the predictive model at various levels. The effect of low-level data on the model assessment at the system level is identified by Bayesian inference and factor analysis. The proposed methodology is implemented for hierarchical model validation of three dynamic system problems.

Jiang, Xiaomo; Mahadevan, Sankaran; Urbina, Angel

2010-05-01

315

The Identity Consolidation Inventory (ICI): development and application of a questionnaire for assessing the structuralization of individual identity.  

PubMed

This paper describes the author's effort to develop a self-rating scale to measure the consolidation of identity in a given individual. It describes the construction of the 35-item Identity Consolidation Inventory (ICI) and, as an appendix to the paper, includes the final version of this questionnaire. The scale's reliability and validity are demonstrated via its administration to 238 normal controls, 80 individuals with Borderline Personality Disorder and 13 subjects with Dissociative Identity Disorder ("multiple personality"). The clinical and research usefulness of ICI lies in the realm of discerning the syndrome of identity diffusion that underlies all severe personality disorders. PMID:19295621

Samuel, Steven; Akhtar, Salman

2009-03-01

316

A Structural Equation Analysis of Family Accommodation in Pediatric Obsessive-Compulsive Disorder  

Microsoft Academic Search

Family accommodation of symptoms is counter to the primary goals of cognitive-behavioral therapy for pediatric obsessive-compulsive\\u000a disorder (OCD) and can pose an obstacle to positive treatment outcomes. Although increased attention has been given to family\\u000a accommodation in pediatric OCD, relatively little is known about associated child and parent characteristics, and their mediating\\/moderating\\u000a effects. This study examined a structural equation model

Nicole Elise Caporino; Jessica Morgan; Jason Beckstead; Vicky Phares; Tanya K. Murphy; Eric A. Storch

2011-01-01

317

A general structural equation model with dichotomous, ordered categorical, and continuous latent variable indicators  

Microsoft Academic Search

A structural equation model is proposed with a generalized measurement part, allowing for dichotomous and ordered categorical variables (indicators) in addition to continuous ones. A computationally feasible three-stage estimator is proposed for any combination of observed variable types. This approach provides large-sample chi-square tests of fit and standard errors of estimates for situations not previously covered. Two multiple-indicator modeling examples

Bengt Muthén

1984-01-01

318

Second order scheme for Maxwell's equations with discontinuous dielectric permittivity on structured meshes  

NASA Astrophysics Data System (ADS)

A second order finite volume scheme for numerical solution of Maxwell's equations with discontinuous dielectric permittivity on structured meshes is suggested. The scheme is based on approaches of Godunov, Lax-Wendroff and Van Leer. The distinctive feature of the suggested scheme is calculation and limitation of derivatives that ensures second order of approximation even in the cells adjacent to dielectric permittivity discontinuity. Numerical tests for problems with linear and curvilinear dielectric permittivity discontinuities confirm second order of approximation.

Ismagilov, Timur Z.

2013-10-01

319

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

Microsoft Academic Search

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 internalizing distress (e.g., anxiety, depression), externalizing distress (e.g., aggression), and recovery outcomes following traumatic events.

Susan E. Borja; Jennifer L. Callahan

2009-01-01

320

Abstract: Evaluation of Test Statistics for Robust Structural Equation Modeling With Nonnormal Missing Data  

Microsoft Academic Search

Traditional structural equation modeling (SEM) techniques have trouble dealing with incomplete and\\/or nonnormal data that are often encountered in practice. Yuan and Zhang (2011a) developed a two-stage procedure for SEM to handle nonnormal missing data and proposed four test statistics for overall model evaluation. Although these statistics have been shown to work well with complete data, their performance for incomplete

Xin Tong; Zhiyong Zhang; Ke-Hai Yuan

2011-01-01

321

An Examination of Statistical Power in Multigroup Dynamic Structural Equation Models  

Microsoft Academic Search

This study used statistical simulation to calculate differential statistical power in dynamic structural equation models with groups (as in McArdle & Prindle, 2008). Patterns of between-group differences were simulated to provide insight into how model parameters influence power approximations. Chi-square and root mean square error of approximation (RMSEA) power approximation procedures were used to compare the effects of parameter manipulations

John J. Prindle; John J. McArdle

2012-01-01

322

A ballistic limit equation for hypervelocity impacts on composite honeycomb sandwich panel satellite structures  

Microsoft Academic Search

During a recent experimental test campaign performed in the framework of ESA Contract 16721, the ballistic performance of multiple satellite-representative Carbon Fibre Reinforced Plastic (CFRP)\\/Aluminium honeycomb sandwich panel structural configurations (GOCE, Radarsat-2, Herschel\\/Planck, BeppoSax) was investigated using the two-stage light-gas guns at EMI. The experimental results were used to develop and validate a new empirical Ballistic Limit Equation (BLE), which

S. Ryan; F. Schaefer; R. Destefanis; M. Lambert

2008-01-01

323

Individual and environmental correlates of dietary fat intake in rural communities: A structural equation model analysis  

Microsoft Academic Search

Total dietary fat and saturated fat intake are associated with obesity, elevated cholesterol, and heart disease. This study tested a multi-group structural equation model to explore differences in the relative influence of individual, social, and physical environment factors on dietary fat intake amongst adults aged 40–70 years. Participants from four rural Georgia, U.S., counties (n = 527) completed a cross-sectional survey that

April K. Hermstad; Deanne W. Swan; Michelle C. Kegler; J. K. Barnette; Karen Glanz

2010-01-01

324

Simulation of switching noise in multi-layer structures using generalized transmission line equation method  

Microsoft Academic Search

This paper discusses the use of the generalized transmission line equations (GTLE) for the simulation of switching noise distribution in multi-layered packaging structures. After a brief discussion on the formulation and its application to a simple dual trace transmission line, two-layered plane and two-layered plane with four drivers and traces, the method has been applied to a complicated fourteen layer

Lixi Wan; Madhavan Swaminathan; R. R. Turnmala

2002-01-01

325

Prescriptive Statements and Educational Practice: What Can Structural Equation Modeling (SEM) Offer?  

Microsoft Academic Search

Longitudinal structural equation modeling (SEM) can be a basis for making prescriptive statements on educational practice\\u000a and offers yields over “traditional” statistical techniques under the general linear model. The extent to which prescriptive\\u000a statements can be made will rely on the appropriate accommodation of key elements of research design, measurement, and theory.\\u000a If these key elements are not adequately incorporated

Andrew J. Martin

2011-01-01

326

A preference free partial differential equation for the term structure of interest rates  

Microsoft Academic Search

The objectives of this paper are two-fold: the first is the reconciliation of the differences between the Vasicek and the\\u000a Heath-Jarrow-Morton approaches to the modelling of term structure of interest rates. We demonstrate that under certain (not\\u000a empirically unreasonable) assumptions prices of interest-rate sensitive claims within the Heath-Jarrow-Morton framework can\\u000a be expressed as a partial differential equation which both is

Carl Chiarella; Nadima El-Hassan

1996-01-01

327

An assessment of the use of partial least squares structural equation modeling in marketing research  

Microsoft Academic Search

Most methodological fields undertake regular critical reflections to ensure rigorous research and publication practices, and,\\u000a consequently, acceptance in their domain. Interestingly, relatively little attention has been paid to assessing the use of\\u000a partial least squares structural equation modeling (PLS-SEM) in marketing research—despite its increasing popularity in recent\\u000a years. To fill this gap, we conducted an extensive search in the 30

Joe F. Hair; Marko Sarstedt; Christian M. Ringle; Jeannette A. Mena

328

Structural equation modeling in practice: A review and recommended two-step approach  

Microsoft Academic Search

In this article, we provide guidance for substantive researchers on the use of structural equation modeling in practice for theory testing and development. We present a comprehensive, two-step modeling approach that employs a series of nested models and sequential chi-square difference tests. We discuss the comparative advantages of this approach over a one-step approach. Considerations in specification, assessment of fit,

James C. Anderson; David W. Gerbing

1988-01-01

329

Organizational Learning and Performance in Two National Cultures: A Multi-group Structural Equation Modeling Approach  

Microsoft Academic Search

\\u000a This chapter examines the impact of organizational learning on organizational performance in two countries. Using a multi-group\\u000a structural equation modeling approach on data from 203 Slovenian and 202 Croatian companies, it tests the impact of the organizational\\u000a learning process on financial and non-financial performance (NFP). The results show consistent findings between both countries\\u000a under investigation (which vary only in terms

Miha Škerlavaj; Vlado Dimovski

330

A Bayesian structural equations model for multilevel data with missing responses and missing covariates  

Microsoft Academic Search

Motivated by a large multilevel survey conducted by the US Veterans Health Administration\\u000a(VHA), we propose a structural equations model which involves a set of latent variables to\\u000acapture dependence between different responses, a set of facility level random effects to\\u000acapture facility heterogeneity and dependence between individuals within the same\\u000afacility, and a set of covariates to account for

Sonali Das; Ming-Hui Chen; Sungduk Kim; Nicholas Warren

2008-01-01

331

A Bayesian Approach for Nonlinear Structural Equation Models With Dichotomous Variables Using Logit and Probit Links  

Microsoft Academic Search

Analysis of ordered binary and unordered binary data has received considerable attention in social and psychological research. This article introduces a Bayesian approach, which has several nice features in practical applications, for analyzing nonlinear structural equation models with dichotomous data. We demonstrate how to use the software WinBUGS and R2WinBUGS to obtain Bayesian estimates of the unknown parameters, estimates of

Sik-Yum Lee; Xin-Yuan Song; Jing-Heng Cai

2010-01-01

332

Maximum Likelihood Estimation and Model Comparison for Mixtures of Structural Equation Models with Ignorable Missing Data  

Microsoft Academic Search

The objective of this paper is to develop the maximum likelihood approach\\u000afor analyzing a finite mixture of structural equation models with missing data that are\\u000amissing at random. A Monte Carlo EM algorithm is proposed for obtaining the maximum\\u000alikelihood estimates. A well-known statistic in model comparison, namely the Bayesian\\u000aInformation Criterion (BIC), is used for model comparison. With

Sik-yum Lee; Xin-yuan Song

2003-01-01

333

School as a determinant for health outcomes – a structural equation model analysis  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate whether students' perceptions of their school environment and their adjustment to school are associated with health outcomes across gender and age groups. Design\\/methodology\\/approach – Data from the cross-sectional international Health Behavior in School-aged Children Survey of the year 2002 (n=162 306) were analyzed. A structural equation model (LISREL) specified social

Ulrike Ravens-Sieberer; John Freeman; Gyongyi Kokonyei; Christiane A. Thomas; Michael Erhart

2009-01-01

334

A Structural Equation Model of the Factors Influencing British Consumers' Behaviour toward Animal Welfare  

Microsoft Academic Search

Results of national and pan-European consumer surveys and the growth in the demand for so-called “animal-friendly” food products suggest that consumers within the European Union (EU) show a high level of concern for the welfare of farm animals. This article analyses the determinants of British consumers' behaviour toward animal welfare using structural equation models (SEM) with observed and latent variables.

Luiza Toma; Alistair McVittie; Carmen Hubbard; Alistair W. Stott

2011-01-01

335

Bayesian structural equation modeling: a more flexible representation of substantive theory.  

PubMed

This article proposes a new approach to factor analysis and structural equation modeling using Bayesian analysis. The new approach replaces parameter specifications of exact zeros with approximate zeros based on informative, small-variance priors. It is argued that this produces an analysis that better reflects substantive theories. The proposed Bayesian approach is particularly beneficial in applications where parameters are added to a conventional model such that a nonidentified model is obtained if maximum-likelihood estimation is applied. This approach is useful for measurement aspects of latent variable modeling, such as with confirmatory factor analysis, and the measurement part of structural equation modeling. Two application areas are studied, cross-loadings and residual correlations in confirmatory factor analysis. An example using a full structural equation model is also presented, showing an efficient way to find model misspecification. The approach encompasses 3 elements: model testing using posterior predictive checking, model estimation, and model modification. Monte Carlo simulations and real data are analyzed using Mplus. The real-data analyses use data from Holzinger and Swineford's (1939) classic mental abilities study, Big Five personality factor data from a British survey, and science achievement data from the National Educational Longitudinal Study of 1988. PMID:22962886

Muthén, Bengt; Asparouhov, Tihomir

2012-09-01

336

Ridge structural equation modelling with correlation matrices for ordinal and continuous data.  

PubMed

This paper develops a ridge procedure for structural equation modelling (SEM) with ordinal and continuous data by modelling the polychoric/polyserial/product-moment correlation matrix R. Rather than directly fitting R, the procedure fits a structural model to R(a) =R+aI by minimizing the normal distribution-based discrepancy function, where a > 0. Statistical properties of the parameter estimates are obtained. Four statistics for overall model evaluation are proposed. Empirical results indicate that the ridge procedure for SEM with ordinal data has better convergence rate, smaller bias, smaller mean square error, and better overall model evaluation than the widely used maximum likelihood procedure. PMID:21506947

Yuan, Ke-Hai; Wu, Ruilin; Bentler, Peter M

2011-02-01

337

Testing mediation using multiple regression and structural equation modeling analyses in secondary data.  

PubMed

Mediation analysis in child and adolescent development research is possible using large secondary data sets. This article provides an overview of two statistical methods commonly used to test mediated effects in secondary analysis: multiple regression and structural equation modeling (SEM). Two empirical studies are presented to illustrate the respective circumstances in which the two methods are most useful. One study examines the mediated effect of parents' social capital on parent involvement in Head Start programs through parent-child bond. The other study assesses the mediating effects of structured routine activities, delinquent association, and prosocial belief on the relationship between religiosity and juvenile delinquency. PMID:21917711

Li, Spencer D

2011-06-01

338

How Structure Sense for Algebraic Expressions or Equations Is Related to Structure Sense for Abstract Algebra  

ERIC Educational Resources Information Center

|Many students have difficulties with basic algebraic concepts at high school and at university. In this paper two levels of algebraic structure sense are defined: for high school algebra and for university algebra. We suggest that high school algebra structure sense components are sub-components of some university algebra structure sense…

Novotna, Jarmila; Hoch, Maureen

2008-01-01

339

Nonlinear propagation of light in structured media: Generalized unidirectional pulse propagation equations.  

PubMed

Unidirectional pulse propagation equations [UPPE, Phys. Rev. E 70, 036604 (2004)] have provided a theoretical underpinning for computer-aided investigations into dynamics of high-power ultrashort laser pulses and have been successfully utilized for almost a decade. Unfortunately, they are restricted to applications in bulk media or, with additional approximations, to simple waveguide geometries in which only a few guided modes can approximate the propagating waveform. The purpose of this work is to generalize the directional pulse propagation equations to structures characterized by strong refractive index differences and material interfaces. We also outline a numerical solution framework that draws on the combination of the bulk-media UPPE method with single-frequency beam-propagation techniques. PMID:23031052

Andreasen, J; Kolesik, M

2012-09-27

340

The Response to Questionnaire Portion of Report No. 1; Preliminary Report, Control of Pavement Movements Adjacent to Structures.  

National Technical Information Service (NTIS)

The following two major questions wwere posed: 1. How prevalent is damage to structures from movement of rigid pavements in your State. 2. What action has been taken or considered to control, prevent or repair damage to structures from pavement movement. ...

1965-01-01

341

Questionnaire Development Resources  

Cancer.gov

Resources made available by DCEG for use in developing study questionnaires. Includes questionnaires reviewed and approved by DCEG’s Technical Evaluation Committee, as well as non-reviewed questionnaire modules to be used as starting points for development.

342

A special purpose symbolic manipulation program for the derivation of the equations of motion for large flexible structures  

Microsoft Academic Search

This paper outlines a computer program especially tailored to the task of deriving explicit equations of motion for structures with point-connected substructures. The special purpose program is written in FORTRAN and is designed for performing the specific algebraic operations encountered in the derivation of explicit equations of motion. The derivation is by the Lagrangian approach. Using an orderly kinematical procedure

A. L. Hale; L. Meirovitch

1977-01-01

343

OpenMx: An Open Source Extended Structural Equation Modeling Framework  

PubMed Central

OpenMx is free, full–featured, open source, structural equation modeling (SEM) software. OpenMx runs within the R statistical programming environment on Windows, Mac OS–X, and Linux computers. The rationale for developing OpenMx is discussed along with the philosophy behind the user interface. The OpenMx data structures are introduced — these novel structures define the user interface framework and provide new opportunities for model specification. Two short example scripts for the specification and fitting of a confirmatory factor model are next presented. We end with an abbreviated list of modeling applications available in OpenMx 1.0 and a discussion of directions for future development.

Boker, Steven; Neale, Michael; Maes, Hermine; Wilde, Michael; Spiegel, Michael; Brick, Timothy; Spies, Jeffrey; Estabrook, Ryne; Kenny, Sarah; Bates, Timothy; Mehta, Paras; Fox, John

2012-01-01

344

Electronic structure, equation of state, and lattice dynamics of low-pressure Ge polymorphs  

NASA Astrophysics Data System (ADS)

With the interest of obtaining more information on the low-energy phase diagram of germanium and its degree of similarity with silicon, we have performed first-principles calculations of the electronic structure and lattice dynamics of the R8, BC8, ST12, and hexagonal diamond structures of Ge. To aid future experimental investigation, we include predictions of the Raman-active frequencies of these phases as well as present the full phonon dispersion throughout the zone. Calculated equation of states within the local density approximation reveal a small pressure region where the R8 phase is energetically favored over the other metastable BC8 and ST12 structures, although the energy differences involved are relatively small and affected by the approximations used in the choice of pseudopotential.

Malone, Brad D.; Cohen, Marvin L.

2012-08-01

345

Psychosocial Problems Among Truant Youth: A Multi-Group, Exploratory Structural Equation Modeling Analysis  

PubMed Central

Truant youth represent a critical group needing problem-oriented research and involvement in effective services. The limited number of studies on the psychosocial functioning of truant youths have focused on one or a few problem areas, rather than examining co-morbid problem behaviors. The present study addresses the need to examine the interrelationships of multiple domains of psychosocial functioning, including substance involvement, mental health, and delinquency, among truant youth. Exploratory structural equation modeling on baseline data collected on 219 truant youths identified two major factors reflecting psychosocial functioning, and found the factor structure was similar across major sociodemographic subgroups. Further analyses supported the validity of the factor structure. The research and service delivery implications of the findings are discussed.

Dembo, Richard; Briones-Robinson, Rhissa; Barrett, Kimberly; Winters, Ken C.; Ungaro, Rocio; Karas, Lora; Wareham, Jennifer; Belenko, Steven

2012-01-01

346

Ballistic Electrons in a Submicron Semiconducting Structure: a Boltzmann Equation Approach  

NASA Astrophysics Data System (ADS)

The distribution function is calculated for electrons in a prototypical submicron semiconducting structure, the N('+)-N('-)-N('+) device. The high fields and small active region in a submicron structure require that hot electrons, rapidly varying densities and electric fields, and ballistic electrons be included self-consistently in any treatment of transport in these structures. The term ballistic electrons refers to those electrons which cross the active region of the structure (the thin N('-) layer) without scattering. All three of these effects are included by directly solving the coupled Boltzmann and Poisson equations wiin the relaxation-time approximation. This is the first solution of a Boltzmann equation in an inhomogeneous semiconducting structure. Both a simple one-relaxation-time, single-parabolic -band model and a more sophisticated model for GaAs which includes two valleys in the conduction band are used. The distribution function that results from this calculation shows a great deal of structure and cannot be simply characterized by its low-order velocity moments. In particular, for both relaxation models the distribution exhibits a strikingly prominent peak caused by ballistic electrons. Closely connected to the presence of the ballistic peak is "cooling" of the electrons near the upstream N('+)/N(' -) step and subsequent "heating" as the electrons cross the N('-) region. In spite of these dramatic non-equilibrium phenomena, the I-V characteristic is linear in the voltage range studied. In addition, the current is surprisingly insensitive to the choice of the relaxation-time. In the two-valley model, transfer between the two valleys causes a buildup of electrons in the higher energy valley in the N('-) region. Transfer of the electrons back to the lower energy valley near the downstream N('+)/N(' -) step creates additional peaks in the distribution function which we call ballistic electron echoes. The universal features of this new effect as well as of the ballistic effects are emphasized.

Baranger, Harold Urey

347

Einstein equations and conformal structure: Existence of anti-de Sitter-type space-times  

Microsoft Academic Search

We discuss Einstein's equations in the context of normal conformal Cartan connections, derive a new conformal representation of the equations, and express the equations in a conformally invariant gauge. The resulting formulation of the equations is used to show the existence of asymptotically simple solutions to Einstein's equations with a positive cosmological constant. The solutions are characterized by Cauchy data

Helmut Friedrich

1995-01-01

348

Using Instrumental Variable (IV) Tests to Evaluate Model Specification in Latent Variable Structural Equation Models.  

PubMed

Structural Equation Modeling with latent variables (SEM) is a powerful tool for social and behavioral scientists, combining many of the strengths of psychometrics and econometrics into a single framework. The most common estimator for SEM is the full-information maximum likelihood estimator (ML), but there is continuing interest in limited information estimators because of their distributional robustness and their greater resistance to structural specification errors. However, the literature discussing model fit for limited information estimators for latent variable models is sparse compared to that for full information estimators. We address this shortcoming by providing several specification tests based on the 2SLS estimator for latent variable structural equation models developed by Bollen (1996). We explain how these tests can be used to not only identify a misspecified model, but to help diagnose the source of misspecification within a model. We present and discuss results from a Monte Carlo experiment designed to evaluate the finite sample properties of these tests. Our findings suggest that the 2SLS tests successfully identify most misspecified models, even those with modest misspecification, and that they provide researchers with information that can help diagnose the source of misspecification. PMID:20419054

Kirby, James B; Bollen, Kenneth A

2009-07-01

349

A ballistic limit equation for hypervelocity impacts on composite honeycomb sandwich panel satellite structures  

NASA Astrophysics Data System (ADS)

During a recent experimental test campaign performed in the framework of ESA Contract 16721, the ballistic performance of multiple satellite-representative Carbon Fibre Reinforced Plastic (CFRP)/Aluminium honeycomb sandwich panel structural configurations (GOCE, Radarsat-2, Herschel/Planck, BeppoSax) was investigated using the two-stage light-gas guns at EMI. The experimental results were used to develop and validate a new empirical Ballistic Limit Equation (BLE), which was derived from an existing Whipple-shield BLE. This new BLE provided a good level of accuracy in predicting the ballistic performance of stand-alone sandwich panel structures. Additionally, the equation is capable of predicting the ballistic limit of a thin Al plate located at a standoff behind the sandwich panel structure. This thin plate is the representative of internal satellite systems, e.g. an Al electronic box cover, a wall of a metallic vessel, etc. Good agreement was achieved with both the experimental test campaign results and additional test data from the literature for the vast majority of set-ups investigated. For some experiments, the ballistic limit was conservatively predicted, a result attributed to shortcomings in correctly accounting for the presence of high surface density multi-layer insulation on the outer facesheet. Four existing BLEs commonly applied for application with stand-alone sandwich panels were reviewed using the new impact test data. It was found that a number of these common approaches provided non-conservative predictions for sandwich panels with CFRP facesheets.

Ryan, S.; Schaefer, F.; Destefanis, R.; Lambert, M.

350

Using Instrumental Variable (IV) Tests to Evaluate Model Specification in Latent Variable Structural Equation Models*  

PubMed Central

Structural Equation Modeling with latent variables (SEM) is a powerful tool for social and behavioral scientists, combining many of the strengths of psychometrics and econometrics into a single framework. The most common estimator for SEM is the full-information maximum likelihood estimator (ML), but there is continuing interest in limited information estimators because of their distributional robustness and their greater resistance to structural specification errors. However, the literature discussing model fit for limited information estimators for latent variable models is sparse compared to that for full information estimators. We address this shortcoming by providing several specification tests based on the 2SLS estimator for latent variable structural equation models developed by Bollen (1996). We explain how these tests can be used to not only identify a misspecified model, but to help diagnose the source of misspecification within a model. We present and discuss results from a Monte Carlo experiment designed to evaluate the finite sample properties of these tests. Our findings suggest that the 2SLS tests successfully identify most misspecified models, even those with modest misspecification, and that they provide researchers with information that can help diagnose the source of misspecification.

Kirby, James B.; Bollen, Kenneth A.

2009-01-01

351

Equations of State of Dual Functional Mixtures Of Structural Energetic Materials  

NASA Astrophysics Data System (ADS)

Currently, the electronic structure and the equation of state of metals can be determined by the use of the density functional theory. However, the subject is still an active research field for disordered materials like alloys. This paper, however, is concerned with mixtures like aluminum, nickel and nickel oxide and not alloys. In general the mixture can be disordered and the ratio of the constituents can vary to accommodate the needed application and the associated structural design. In this paper, thermodynamically complete equations of state of mixtures are obtained from first principles calculations. Specifically mixtures of aluminum and nickel or nickel oxide, titanium and silicon, with binders and porosity, are considered. First, EOS of individual components is determined. Then, a super cell is constructed by the use of other disordered theories but noting the fact that we are considering mixtures and not alloys. Methods similar to the direct sampling method, quasi-random structures method and virtual crystal approximation are used to represent proper mixture architecture, with porosity. The results are then bridged to continuum though statistical mechanics techniques and compared with the results obtained from continuum mixture theories. To determine thermal effects, lattice thermal contributions and electron thermal contributions are included. The transition states are also discussed.

Hanagud, Sathya; Zaharieva, Rusislava; Lu, Xia

2007-06-01

352

Structural equation model testing and the quality of natural killer cell activity measurements  

PubMed Central

Background Browne et al. [Browne, MacCallum, Kim, Andersen, Glaser: When fit indices and residuals are incompatible. Psychol Methods 2002] employed a structural equation model of measurements of target cell lysing by natural killer cells as an example purportedly demonstrating that small but statistically significant ill model fit can be dismissed as "negligible from a practical point of view". Methods Reanalysis of the natural killer cell data reveals that the supposedly negligible ill fit obscured important, systematic, and substantial causal misspecifications. Results A clean-fitting structural equation model indicates that measurements employing higher natural-killer-cell to target-cell ratios are more strongly influenced by a progressively intrusive factor, whether or not the natural killer cell activity is activated by recombinant interferon ? (rIFN ?). The progressive influence may reflect independent rate limiting steps in cell recognition and attachment, spatial competition for cell attachment points, or the simultaneous lysings of single target cells by multiple natural killer cells. Conclusions If the progressively influential factor is ultimately identified as a mere procedural impediment, the substantive conclusion will be that measurements of natural killer cell activity made at lower effector to target ratios are more valid. Alternatively, if the individual variations in the progressively influential factor are modifiable, this may presage a new therapeutic route to enhancing natural killer cell activity. The methodological conclusion is that, when using structural equation models, researchers should attend to significant model ill fit even if the degree of covariance ill fit is small, because small covariance residuals do not imply that the underlying model misspecifications are correspondingly small or inconsequential.

Hayduk, Leslie A; Pazderka-Robinson, Hannah; Cummings, Greta G; Levers, Merry-Jo D; Beres, Melanie A

2005-01-01

353

Structural equation models to estimate risk of infection and tolerance to bovine mastitis  

PubMed Central

Background One method to improve durably animal welfare is to select, as reproducers, animals with the highest ability to resist or tolerate infection. To do so, it is necessary to distinguish direct and indirect mechanisms of resistance and tolerance because selection on these traits is believed to have different epidemiological and evolutionary consequences. Methods We propose structural equation models with latent variables (1) to quantify the latent risk of infection and to identify, among the many potential mediators of infection, the few ones that influence it significantly and (2) to estimate direct and indirect levels of tolerance of animals infected naturally with pathogens. We applied the method to two surveys of bovine mastitis in the Walloon region of Belgium, in which we recorded herd management practices, mastitis frequency, and results of bacteriological analyses of milk samples. Results and discussion Structural equation models suggested that, among more than 35 surveyed herd characteristics, only nine (age, addition of urea in the rations, treatment of subclinical mastitis, presence of dirty liner, cows with hyperkeratotic teats, machine stripping, pre- and post-milking teat disinfection, and housing of milking cows in cubicles) were directly and significantly related to a latent measure of bovine mastitis, and that treatment of subclinical mastitis was involved in the pathway between post-milking teat disinfection and latent mastitis. These models also allowed the separation of direct and indirect effects of bacterial infection on milk productivity. Results suggested that infected cows were tolerant but not resistant to mastitis pathogens. Conclusions We revealed the advantages of structural equation models, compared to classical models, for dissecting measurements of resistance and tolerance to infectious diseases, here bovine mastitis. Using our method, we identified nine major risk factors that were directly associated with an increased risk of mastitis and suggested that cows were tolerant but not resistant to mastitis. Selection should aim at improved resistance to infection by mastitis pathogens, although further investigations are needed due to the limitations of the data used in this study.

2013-01-01

354

A Structural Equation Model of Perievent Panic and Posttraumatic Stress Disorder After a Community Disaster  

PubMed Central

Studies suggest that perievent panic attacks are predictive of future posttraumatic stress disorder (PTSD). Using a population of New York City residents interviewed after the World Trade Center Disaster, the authors measured event exposure, perievent panic, potential confounding, mediating variables, and PTSD. When they estimated a structural equation model, with other stressor events, psychological resources, and Year 1 and Year 2 PTSD as latent variables and adjusted for confounders, the association between perievent panic and Year 2 PTSD was not significant. Results revealed that perievent panic was predictive of Year 1 PTSD, but not Year 2 PTSD. Year 2 stressors and Year 2 psychosocial resources were the best predictors of Year 2 PTSD.

Adams, Richard E.; Boscarino, Joseph A.

2012-01-01

355

Soliton Kinetic Equations with Non-Kolmogorovian Structure: A New Tool for Biological Modeling?  

NASA Astrophysics Data System (ADS)

Non-commutative diagrams, where X --> Y --> Z is allowed and X --> Z --> Y is not, may equally well apply to Malusian experiments with photons traversing polarizers, and to sequences of elementary chemical reactions. This is why non-commutative probabilistic, logical, and dynamical structures necessarily occur in chemical or biological dynamics. We discuss several explicit examples of such systems and propose an exactly solvable nonlinear toy model of a ``brain-heart'' system. The model involves non-Kolmogorovian probability calculus and soliton kinetic equations integrable by Darboux transformations.

Aerts, Diederik; Czachor, Marek; Gabora, Liane; Polk, Philippe

2006-01-01

356

Accurate response surface approximations for weight equations based on structural optimization  

NASA Astrophysics Data System (ADS)

Accurate weight prediction methods are vitally important for aircraft design optimization. Therefore, designers seek weight prediction techniques with low computational cost and high accuracy, and usually require a compromise between the two. The compromise can be achieved by combining stress analysis and response surface (RS) methodology. While stress analysis provides accurate weight information, RS techniques help to transmit effectively this information to the optimization procedure. The focus of this dissertation is structural weight equations in the form of RS approximations and their accuracy when fitted to results of structural optimizations that are based on finite element analyses. Use of RS methodology filters out the numerical noise in structural optimization results and provides a smooth weight function that can easily be used in gradient-based configuration optimization. In engineering applications RS approximations of low order polynomials are widely used, but the weight may not be modeled well by low-order polynomials, leading to bias errors. In addition, some structural optimization results may have high-amplitude errors (outliers) that may severely affect the accuracy of the weight equation. Statistical techniques associated with RS methodology are sought in order to deal with these two difficulties: (1) high-amplitude numerical noise (outliers) and (2) approximation model inadequacy. The investigation starts with reducing approximation error by identifying and repairing outliers. A potential reason for outliers in optimization results is premature convergence, and outliers of such nature may be corrected by employing different convergence settings. It is demonstrated that outlier repair can lead to accuracy improvements over the more standard approach of removing outliers. The adequacy of approximation is then studied by a modified lack-of-fit approach, and RS errors due to the approximation model are reduced by using higher order polynomials. In addition, remaining error in the RS weight equation is characterized, and two error measures are introduced. One of the measures is qualitative, and it is used to identify regions of design space where RS accuracy may be poor. The second measure is quantitative, but conservative. Its use is demonstrated for incorporating the uncertainty due to RS weight equation with parameter uncertainty in order to compare competing designs for robustness.

Papila, Melih

357

Pressure-induced structural phase transition and equation of state of LiTaO3  

NASA Astrophysics Data System (ADS)

Using in situ high-pressure x-ray diffraction and ab initio techniques, a high-pressure structure of LiTaO3 has been determined to be an orthorhombic phase with the space group Pnma. At ambient temperature, the transition pressure from the R3c phase (the ordinary phase at ambient pressure and temperature) to the Pnma phase is about 33.0 GPa and the phase transition is reversible. This phase transition can be reproduced qualitatively by ab initio calculations, but with a lower transition pressure of 19.9 GPa. The equation of state of LiTaO3 is also reported.

Xiang, Shikai; Liu, Lei; Zhao, Jianzhou; Zhou, Xianming; Jing, Qiuming; Zhang, Yi; Liu, Shenggang; Wang, Zhigang; Bi, Yan; Xu, Ji'an; Geng, Huayun; Dai, Chengda; Cai, Lingcang; Wu, Qiang; Liu, Jing; Wang, Chenju; Zhang, Xiulu

2013-05-01

358

Structural equation model-based genome scan for the metabolic syndrome  

Microsoft Academic Search

Background  The metabolic syndrome is characterized by the clustering of several traits, including obesity, hypertension, decreased levels\\u000a of HDL cholesterol, and increased levels of glucose and triglycerides. Because these traits cluster, there are likely common\\u000a genetic factors involved.\\u000a \\u000a \\u000a \\u000a \\u000a Results  We used a multivariate structural equation model (SEM) approach to scan the genome for loci involved in the metabolic syndrome.\\u000a We found moderate

Catherine M Stein; Yeunjoo Song; Robert C Elston; Gyungah Jun; Hemant K Tiwari; Sudha K Iyengar

2003-01-01

359

Unitary Integration: A Numerical Technique Preserving the Structure of the Quantum Liouville Equation  

SciTech Connect

The quantum Liouville equation for an n-level atomic system driven by external fields has a nontrivial kinematic structure; the quantities tr {rho}{sup j}, j=1,2,{hor_ellipsis},n remain constant in time, independent of the Hamiltonian. These invariants are physically significant; the qualitative character of the solution depends on their existence. A generic numerical method will not, in general, preserve these invariants. We present a numerical technique which evolves the density matrix {ital via} unitary transformations thus {ital exactly} preserving these invariants to {ital all orders} in the time step. {copyright} {ital 1997} {ital The American Physical Society}

Shadwick, B.A.; Buell, W.F. [Institute for Advanced Physics, P.O. Box 199, 10875 U.S. Highway 285, Conifer, Colorado 80433 (United States); Shadwick, B.A. [Physics Department, University of California at Berkeley, Berkeley, California 94720-7300 (United States)

1997-12-01

360

Measuring worksite health promotion programs: an application of structural equation modeling with ordinal data.  

PubMed

This paper presents a model for measuring the outcome of Worksite Health Promotion Programs through an application of Structural Equation Modeling with ordinal data. We model the function "being healthy" as a vector comprised of three latent or unobservable variables: Health Status, Lifestyle and Stress. Each variable can be measured only indirectly through a set of manifest or observable ordinal indicators. The objective is to derive and analyze the distributions, and changes in distributions over time, of the latent variables on an individual level. The model is analyzed empirically on data from three large Swedish manufacturing firms. PMID:22815096

Odegaard, Fredrik; Roos, Pontus

2012-07-20

361

A Unified Approach to Two-Level Structural Equation Models and Linear Mixed Effects Models  

Microsoft Academic Search

\\u000a Two-level structural equation models (two-level SEM for simplicity) are widely used to analyze correlated clustered data (or\\u000a two-level data) such as data collected from students (level-1 units) nested in different schools (level-2 units), or data\\u000a collected from siblings (level-1 units) nested in different families (level-2 units). These data are usually collected by\\u000a two sampling steps: randomly choosing some level-2 units;

Peter M. Bentler; Jiajuan Liang

362

The Use of Structural Equation Modeling in Stuttering Research: Concepts and Directions  

PubMed Central

This article provides a brief introduction to the history and applications of the class of data analytic techniques collectively known as Structural Equation Modeling (SEM). Using an example based on psychological factors thought to affect the likelihood of stuttering, we discuss the issues of specification, identification, and model fit and modification in SEM. We also address points relating to model specification strategies, item parceling, advanced modeling, and suggestions for reporting SEM analyses. It is noted that SEM techniques can contribute to the elucidation of the developmental pathways that lead to stuttering.

Levine, Stephen Z.; Petrides, K. V.; Davis, Stephen; Jackson, Chris J.; Howell, Peter

2007-01-01

363

A macroion correlation effect on the structure of charged stabilized colloidal suspensions: a self-consistent integral equation study  

Microsoft Academic Search

Using the mean field Poisson–Boltzmann (PB) and the Ornstein–Zernike (OZ) integral equation theories, we have determined the\\u000a macroions effective interactions and the structure of charged stabilized colloidal suspension for a large charge range of\\u000a macroion and screening parameter values. The renormalized parameters are calculated by solving the PB equation written in\\u000a the framework of the modified Jellium model. The structures

Fatiha Smain; Fouzia Ould-Kaddour

2010-01-01

364

Evolution of spin-dependent structure functions from DGLAP equations in leading order and next to leading order  

SciTech Connect

In this paper the spin-dependent singlet and nonsinglet structure functions have been obtained by solving Dokshitzer, Gribov, Lipatov, Altarelli, Parisi evolution equations in leading order and next to leading order in the small x limit. Here we have used Taylor series expansion and then the method of characteristics to solve the evolution equations. We have also calculated t and x evolutions of deuteron structure functions, and the results are compared with the SLAC E-143 Collaboration data.

Baishya, R.; Jamil, U.; Sarma, J. K. [Physics Department, J. N. College, Boko-781123, Assam (India); Physics Department, Tezpur University, Napaam-784028, Assam (India)

2009-02-01

365

Bayesian analysis of non-linear structural equation models with non-ignorable missing outcomes from reproductive dispersion models  

Microsoft Academic Search

Non-linear structural equation models are widely used to analyze the relationships among outcomes and latent variables in modern educational, medical, social and psychological studies. However, the existing theories and methods for analyzing non-linear structural equation models focus on the assumptions of outcomes from an exponential family, and hence can’t be used to analyze non-exponential family outcomes. In this paper, a

Nian-Sheng Tang; Xing Chen; Ying-Zi Fu

2009-01-01

366

The large scale structure of the universe, the Burgers equation and cellular structures  

Microsoft Academic Search

The most advanced theory to explain the formation of the large scale structure of the universe is based on the theory of gravitational instability in the expanding universe. The nonlinear stage of the gravitational instability is shown to be approximately described in the frame of the \\

S. Gurbatov; A. Saichev; S. Shandarin

1990-01-01

367

Confirming the Structure of the "Why Do You Smoke?" Questionnaire: A Community Resource for Adolescent Tobacco Cessation  

ERIC Educational Resources Information Center

In response to the problem of adolescent smoking and limited appropriate cessation resources, this study examined the pattern and structure of the American Lung Association, Why Do You Smoke? (WDS) to determine its appropriateness for use in youth smoking cessation programs. The WDS is used to help smokers identify primary motivations for using…

Smith, Dennis W.; Lee, Jay T.; Colwell, Brian; Stevens-Manser, Stacey

2008-01-01

368

The Survey Questionnaire  

ERIC Educational Resources Information Center

|Internet-based surveys are still relatively new, and researchers are just beginning to articulate best practices for questionnaire design. Online questionnaire design has generally been guided by the principles applying to other self-administered instruments, such as paper-based questionnaires. Web-based questionnaires, however, have the…

Ritter, Lois A. Ed.; Sue, Valerie M., Ed.

2007-01-01

369

Vector Autoregression, Structural Equation Modeling, and Their Synthesis in Neuroimaging Data Analysis  

PubMed Central

Vector autoregression (VAR) and structural equation modeling (SEM) are two popular brain-network modeling tools. VAR, which is a data-driven approach, assumes that connected regions exert time-lagged influences on one another. In contrast, the hypothesis-driven SEM is used to validate an existing connectivity model where connected regions have contemporaneous interactions among them. We present the two models in detail and discuss their applicability to FMRI data, and interpretational limits. We also propose a unified approach that models both lagged and contemporaneous effects. The unifying model, structural vector autoregression (SVAR), may improve statistical and explanatory power, and avoids some prevalent pitfalls that can occur when VAR and SEM are utilized separately.

Chen, Gang; Glen, Daniel R.; Saad, Ziad S.; Hamilton, J. Paul; Thomason, Moriah E.; Gotlib, Ian H.; Cox, Robert W.

2011-01-01

370

Prospective memory in healthy Chinese people: the latent structure of the Comprehensive Assessment of Prospective Memory Questionnaire.  

PubMed

This study aimed to examine the latent structure of the Chinese version of the Comprehensive Assessment of Prospective Memory (CAPM) using confirmatory factor analysis. A total of 264 healthy Chinese participants (118 men and 146 women) took part in the study and their ages ranged from 17 to 90 years. There was no gender effect upon the frequency of prospective memory (PM) forgetting but age and education were found to be correlated significantly with these frequencies in the current sample. Results of the study also showed that the model with the best fit had a tripartite structure which consisted of a general memory factor (with all items loading on it) plus a basic activities of daily living as well as an instrumental activities of daily living factor. Furthermore, this tripartite model was robust across subgroups with respect to gender, education, and age. These findings provide support for the construct validity of the original CAPM and demonstrate its utility in another culture. PMID:20155572

Chan, Raymond C K; Qing, Yonghong; Wu, Qiuping; Shum, David

2010-02-01

371

The Structure of Preschoolers’ Emotion Knowledge: Model Equivalence and Validity Using a Structural Equation Modeling Approach  

Microsoft Academic Search

Research Findings: A theory-based 2-factor structure of preschoolers’ emotion knowledge (i.e., recognition of emotional expression and understanding of emotion-eliciting situations) was tested using confirmatory factor analysis. Compared to 1- and 3-factor models, the 2-factor model showed a better fit to the data. The model was found to be equivalent for gender, race, age, and socioeconomic risk. Theory and the high

Hideko Hamada Bassett; Susanne Denham; Melissa Mincic; Kelly Graling

2012-01-01

372

The Marital Satisfaction Questionnaire for Older Persons  

Microsoft Academic Search

Five studies were conducted to construct and psychometrically evaluate a marital satisfaction questionnaire for older persons. The questionnaire content was generated and refined in Study 1. Temporal stability was evaluated in Study 2, and criterion-related validity was examined in Study 3. Norms, factor structure, and construct validity of the questionnaire were established in Study 4. The degree to which scores

Stephen N. Haynes; Frank J. Floyd; Carolyn Lemsky; Elizabeth Rogers

1992-01-01

373

The Marital Satisfaction Questionnaire For Older Persons  

Microsoft Academic Search

Five studies were conducted to construct and psychometrically evaluate a marital satisfaction questionnaire for older persons. The questionnaire content was generated and refined in Study 1. Temporal stability was evaluated in Study 2, and criterion-related validity was examined in Study 3. Norms, factor structure, and construct validity of the questionnaire were established in Study 4. The degree to which scores

Stephen N. Haynes; Frank J. Floyd; Carolyn Lemsky; Elizabeth Rogers; David Winemiller; Nancy Heilman; Mary Werle; Tria Murphy; Lydia Cardone

1992-01-01

374

Longitudinal structure of Pc3 pulsations on the ground near the magnetic equator  

NASA Astrophysics Data System (ADS)

It has been generally accepted that there are two models for the propagation mechanism of Pc3 pulsations observed on the ground near the magnetic equator, as follows: (1) Compressional waves, propagating along the equatorial plane of the magnetosphere across the ambient magnetic field lines, arrive at the equatorial ionosphere and couple with the magnetic perturbations on the ground through the ionosphere (compressional wave model); (2) Alfvén waves or compressional waves, propagating into the high-latitude ionosphere, generate large-scale ionospheric current oscillations there, and then they leak to the low latitude and cause Pc3 pulsations near the magnetic equator (ionospheric current model). In order to clarify which of these models is more suitable for Pc3 pulsations on the ground near the magnetic equator, the longitudinal structures of their coherence, amplitude, and phase were statistically studied by using three longitudinally separated subequatorial stations, CRI (? = 3.01°, ? = 273.44°), GUA (? = 5.60°, ? = 215.50°), and MUT (? = 6.24°, ? = 192.17°). We found a nearly inphase structure in the 0730-1700 LT sector and a nearly 180° phase shift across 0730 LT for high-coherence Pc3 events in the H component. The longitudinal phase structure can be explained by the ionospheric current model; in this case, the 180° phase shift across 0730 LT means a meridional current along the dawn terminator supplied from the source at higher latitudes. The compressional wave model cannot explain the 180° phase shift across 0730 LT if the ionosphere is assumed as an infinitely thin sheet; however, the compressional wave model still remains as a candidate if we treat the ionosphere as that having a finite thickness. The data at hand do not let us conclude which of the two models is more appropriate; still, the longitudinal phase structure, shown in this paper, is a new finding that has never been reported and is important for understanding how Pc3 pulsations propagate from the magnetosphere to the equatorial ionosphere.

Tanaka, Y.-M.; Yumoto, K.; Yoshikawa, A.; Shinohara, M.; Kawano, H.; Kitamura, T.-I.

2004-03-01

375

Brooding and Pondering: Isolating the Active Ingredients of Depressive Rumination with Exploratory Factor Analysis and Structural Equation Modeling  

ERIC Educational Resources Information Center

Depressive rumination, as assessed by Nolen-Hoeksema's Response Styles Questionnaire (RSQ), predicts the onset, chronicity, and duration of depressed mood. However, some RSQ items contain depressive content and result in a heterogeneous factor structure. After the a priori elimination of items potentially confounded with depressed item content,…

Armey, Michael F.; Fresco, David M.; Moore, Michael T.; Mennin, Douglas S.; Turk, Cynthia L.; Heimberg, Richard G.; Kecmanovic, Jelena; Alloy, Lauren B.

2009-01-01

376

Use of structural equation modeling to test the construct validity of a case definition of Gulf War syndrome  

Microsoft Academic Search

To attempt to replicate the syndrome-like structure identified by exploratory factor analysis of symptom reports from 249 Gulf War veterans of a Naval reserve battalion (the developmental sample), we administered Haley's original symptom questionnaire to 335 Gulf War veterans who served primarily in active-duty US Army units living in North Texas (the validation sample). On the basis of recently validated

Robert W Haley; Gordon D Luk; Frederick Petty

2001-01-01

377

Working conditions, self-perceived stress, anxiety, depression and quality of life: A structural equation modelling approach  

PubMed Central

Background The relationships between working conditions [job demand, job control and social support]; stress, anxiety, and depression; and perceived quality of life factors [physical health, psychological wellbeing, social relationships and environmental conditions] were assessed using a sample of 698 male automotive assembly workers in Malaysia. Methods The validated Malay version of the Job Content Questionnaire (JCQ), Depression Anxiety Stress Scales (DASS) and the World Health Organization Quality of Life-Brief (WHOQOL-BREF) were used. A structural equation modelling (SEM) analysis was applied to test the structural relationships of the model using AMOS version 6.0, with the maximum likelihood ratio as the method of estimation. Results The results of the SEM supported the hypothesized structural model (?2 = 22.801, df = 19, p = 0.246). The final model shows that social support (JCQ) was directly related to all 4 factors of the WHOQOL-BREF and inversely related to depression and stress (DASS). Job demand (JCQ) was directly related to stress (DASS) and inversely related to the environmental conditions (WHOQOL-BREF). Job control (JCQ) was directly related to social relationships (WHOQOL-BREF). Stress (DASS) was directly related to anxiety and depression (DASS) and inversely related to physical health, environment conditions and social relationships (WHOQOL-BREF). Anxiety (DASS) was directly related to depression (DASS) and inversely related to physical health (WHOQOL-BREF). Depression (DASS) was inversely related to the psychological wellbeing (WHOQOL-BREF). Finally, stress, anxiety and depression (DASS) mediate the relationships between job demand and social support (JCQ) to the 4 factors of WHOQOL-BREF. Conclusion These findings suggest that higher social support increases the self-reported quality of life of these workers. Higher job control increases the social relationships, whilst higher job demand increases the self-perceived stress and decreases the self-perceived quality of life related to environmental factors. The mediating role of depression, anxiety and stress on the relationship between working conditions and perceived quality of life in automotive workers should be taken into account in managing stress amongst these workers.

Rusli, Bin Nordin; Edimansyah, Bin Abdin; Naing, Lin

2008-01-01

378

Big Five or Big Two? Superordinate factors in the NEO Five Factor Inventory and the Antisocial Personality Questionnaire  

Microsoft Academic Search

Although it is claimed that the Big Five dimensions of Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness represent the highest level in the hierarchical structure of personality, there is consistent evidence that they are not independent and that two higher order factors underlie them. Two higher order factors also underlie the scales of the Antisocial Personality Questionnaire (APQ). Structural equation modelling

Ronald Blackburn; Stanley J. D. Renwick; John P. Donnelly; Caroline Logan

2004-01-01

379

Modeling and treating internalizing psychopathology in a clinical trial: a latent variable structural equation modeling approach  

PubMed Central

Background Clinical trials are typically designed to test the effect of a specific treatment on a single diagnostic entity. However, because common internalizing disorders are highly correlated (‘co-morbid ’), we sought to establish a practical and parsimonious method to characterize and quantify changes in a broad spectrum of internalizing psychopathology targeted for treatment in a clinical trial contrasting two transdiagnostic psychosocial interventions. Method Alcohol dependence treatment patients who had any of several common internalizing disorders were randomized to a six-session cognitive-behavioral therapy (CBT) experimental treatment condition or a progressive muscle relaxation training (PMRT) comparison treatment condition. Internalizing psychopathology was characterized at baseline and 4 months following treatment in terms of the latent structure of six distinct internalizing symptom domain surveys. Results Exploratory structural equation modeling (ESEM) identified a two-factor solution at both baseline and the 4-month follow-up : Distress (measures of depression, trait anxiety and worry) and Fear (measures of panic anxiety, social anxiety and agoraphobia). Although confirmatory factor analysis (CFA) demonstrated measurement invariance between the time-points, structural models showed that the latent means of Fear and Distress decreased substantially from baseline to follow-up for both groups, with a small but statistically significant advantage for the CBT group in terms of Distress (but not Fear) reduction. Conclusions The approach demonstrated in this study provides a practical solution to modeling co-morbidity in a clinical trial and is consistent with converging evidence pointing to the dimensional structure of internalizing psychopathology.

Kushner, M. G.; Krueger, R. F.; Wall, M. M.; Maurer, E. W.; Menk, J. S.; Menary, K. R.

2013-01-01

380

The Eating Attitudes Test-26 revisited using exploratory structural equation modeling.  

PubMed

Most previous studies have failed to replicate the original factor structure of the 26-item version of the Eating Attitudes Test (EAT-26) among community samples of adolescents. The main objective of the present series of four studies (n?=?2178) was to revisit the factor structure of this instrument among mixed gender community samples of adolescents using both exploratory structural equation modeling (ESEM) and confirmatory factor analysis (CFA). First, results from the ESEM analyses provided satisfactory goodness-of-fit statistics and reliability coefficients for a six-factor model of the EAT with 18 items (EAT-18) closely corresponding to the original seven-factor structure proposed for the 40-item version of the EAT. Second, these analyses were satisfactorily replicated among a new sample of community adolescents using CFA. The results confirmed the factor loading and intercept invariance of this model across gender and age groups (i.e., early and late adolescence), as well as the complete invariance of the EAT-18 measurement model between ethnicities (i.e., European versus African origins) and across weight categories (i.e., underweight, normal weight and overweight). Finally, the last study provided support for convergent validity of the EAT-18 with the Eating Disorder Inventory and with instruments measuring global self-esteem, physical appearance, social physique anxiety and fear of negative appearance evaluation. PMID:23344702

Maïano, Christophe; Morin, Alexandre J S; Lanfranchi, Marie-Christine; Therme, Pierre

2013-07-01

381

Singularity Structures in Coulomb-Type Potentials in Two-Body Dirac Equations of Constraint Dynamics  

SciTech Connect

Two-body Dirac equations (TBDE) of Dirac's relativistic constraint dynamics have been successfully applied to obtain a covariant nonperturbative description of QED and QCD bound states. Coulomb-type potentials in these applications lead naively in other approaches to singular relativistic corrections at short distances that require the introduction of either perturbative treatments or smoothing parameters. We examine the corresponding singular structures in the effective potentials of the relativistic Schroedinger equation obtained from the Pauli reduction of the TBDE. We find that the relativistic Schroedinger equation leads in fact to well-behaved wave function solutions when the full potential and couplings of the system are taken into account. The most unusual case is the coupled triplet system with S=1 and L={l_brace}(J-1),(J+1){r_brace}. Without the inclusion of the tensor coupling, the effective S-state potential would become attractively singular. We show how including the tensor coupling is essential in order that the wave functions be well-behaved at short distances. For example, the S-state wave function becomes simply proportional to the D-state wave function and dips sharply to zero at the origin, unlike the usual S-state wave functions. Furthermore, this behavior is similar in both QED and QCD, independent of the asymptotic freedom behavior of the assumed QCD vector potential. Light- and heavy-quark meson states can be described well by using a simplified linear-plus-Coulomb-type QCD potential apportioned appropriately between world scalar and vector potentials. We use this potential to exhibit explicitly the origin of the large pi-rho splitting and effective chiral symmetry breaking. The TBDE formalism developed here may be used to study quarkonia in quark-gluon plasma environments.

Crater, H. W. [University of Tennessee Space Institute; Yoon, Jin-Hee [Inha University, Korea; Wong, Cheuk-Yin [ORNL

2009-01-01

382

Factor analyses of the Hospital Anxiety and Depression Scale: a Bayesian structural equation modeling approach.  

PubMed

PURPOSE: The latent structure of the Hospital Anxiety and Depression Scale (HADS) has caused inconsistent results in the literature. The HADS is frequently analyzed via maximum likelihood confirmatory factor analysis (ML-CFA). However, the overly restrictive assumption of exact zero cross-loadings and residual correlations in ML-CFA can lead to poor model fits and distorted factor structures. This study applied Bayesian structural equation modeling (BSEM) to evaluate the latent structure of the HADS. METHODS: Three a priori models, the two-factor, three-factor, and bifactor models, were investigated in a Chinese community sample (N = 312) and clinical sample (N = 198) using ML-CFA and BSEM. BSEM specified approximate zero cross-loadings and residual correlations through the use of zero-mean, small-variance informative priors. The model comparison was based on the Bayesian information criterion (BIC). RESULTS: Using ML-CFA, none of the three models provided an adequate fit for either sample. The BSEM two-factor model with approximate zero cross-loadings and residual correlations fitted both samples well with the lowest BIC of the three models and displayed a simple and parsimonious factor-loading pattern. CONCLUSIONS: The study demonstrated that the two-factor structure fitted the HADS well, suggesting its usefulness in assessing the symptoms of anxiety and depression in clinical practice. BSEM is a sophisticated and flexible statistical technique that better reflects substantive theories and locates the source of model misfit. Future use of BSEM is recommended to evaluate the latent structure of other psychological instruments. PMID:23670233

Fong, Ted Chun Tat; Ho, Rainbow Tin Hung

2013-05-14

383

Self-Efficacy, School Resources, Job Stressors and Burnout among Spanish Primary and Secondary School Teachers: A Structural Equation Approach  

ERIC Educational Resources Information Center

|This study examines the relationship between school resources, teacher self-efficacy, potential multi-level stressors and teacher burnout using structural equation modelling. The causal structure for primary and secondary school teachers was also examined. The sample was composed of 724 primary and secondary Spanish school teachers. The changes…

Betoret, Fernando Domenech

2009-01-01

384

Analysis method for transient fields in planar structures by marching-on-in-time integral equation technique  

Microsoft Academic Search

A new numerical algorithm for the analysis of transient electromagnetic fields in planar structures is proposed based on the magnetic field integral equation (MFIE) and marching-on-in-time approach. This algorithm solves the problem of radiation boundary conditions in a natural way unlike the FDTD method which needs an approximated radiation boundary condition imposed at outer boundaries of the structure. The algorithm

Natalia Georgieva; Eikichi Yamashita

1996-01-01

385

Application of Bayesian structural equation modeling for examining phytoplankton dynamics in the Neuse River Estuary (North Carolina, USA)  

Microsoft Academic Search

We introduce a Bayesian structural equation modeling framework to explore the spatiotemporal phytoplankton community patterns in the Neuse River Estuary (study period 1995–2001). The initial hypothesized model considered the influence of the physical environment (flow, salinity, and light availability), nitrogen (dissolved oxidized inorganic nitrogen, and total dissolved inorganic nitrogen), and temperature on total phytoplankton biomass and phytoplankton community structure. Generally,

G. B. Arhonditsis; H. W. Paerl; L. M. Valdes-Weaver; C. A. Stow; L. J. Steinberg; K. H. Reckhow

2007-01-01

386

A Structural Equation Model of HIV-Related Stigma, Depressive Symptoms, and Medication Adherence  

PubMed Central

HIV-related stigma has a damaging effect on health outcomes among people living with HIV (PLWH), as studies have associated it with poor HIV medication adherence and depressive symptoms. We investigated whether depressive symptoms mediate the relationship between stigma and medication adherence. In a cross-sectional study, 720 PLWH completed instruments measuring HIV-related stigma, depressive symptoms, and HIV medication adherence. We used structural equation modeling (SEM) to investigate associations among these constructs. In independent models, we found that poorer adherence was associated with higher levels of stigma and depressive symptoms. In the simultaneous model that included both stigma and depressive symptoms, depression had a direct effect on adherence, but the effect of stigma on adherence was not statistically significant. This pattern suggested that depressive symptoms at least partially mediated the association between HIV-related stigma and HIV medication adherence. These findings suggest that interconnections between several factors have important consequences for adherence.

Rao, Deepa; Feldman, Betsy J.; Fredericksen, Rob J.; Crane, Paul K.; Simoni, Jane M.; Kitahata, Mari M.; Crane, Heidi M.

2011-01-01

387

a Two-Level Second-Order Finite Difference Scheme for the Single Term Structure Equation  

NASA Astrophysics Data System (ADS)

In the paper [6] the classical single factor term structure equation for models that predict non-negative interest rates is numerically studied. For these models the authors proposed a second order accurate three-level finite difference scheme (FDs) using the appropriate boundary conditions at zero. For the same problem we propose a two-level second-order accurate FDs. We also propose an effective algorithm for solving the difference schemes, for which also follows the positivity of the numerical solution. The flexibility of our FDs makes it easy to change the drift and diffusion terms in the model. The numerical experiments confirm the second-order of accuracy of the scheme and the positivity-convexity property.

Chernogorova, T.; Valkov, R.

2011-12-01

388

A Comparison of Methods for Estimating Quadratic Effects in Nonlinear Structural Equation Models  

PubMed Central

Two Monte Carlo simulations were performed to compare methods for estimating and testing hypotheses of quadratic effects in latent variable regression models. The methods considered in the current study were (a) a 2-stage moderated regression approach using latent variable scores, (b) an unconstrained product indicator approach, (c) a latent moderated structural equation method, (d) a fully Bayesian approach, and (e) marginal maximum likelihood estimation. Of the 5 estimation methods, it was found that overall the methods based on maximum likelihood estimation and the Bayesian approach performed best in terms of bias, root-mean-square error, standard error ratios, power, and Type I error control, although key differences were observed. Similarities as well as disparities among methods are highlight and general recommendations articulated. As a point of comparison, all 5 approaches were fit to a reparameterized version of the latent quadratic model to educational reading data.

Harring, Jeffrey R.; Weiss, Brandi A.; Hsu, Jui-Chen

2012-01-01

389

Modeling of Transport Through Submicron Semiconductor Structures: A Direct Solution to the Coupled Poisson-Boltzmann Equations  

Microsoft Academic Search

We report on a computational approach based on the self-consistent solution of the steady-state Boltzmann transport equation coupled with the Poisson equation for the study of inhomogeneous transport in deep submicron semiconductor structures. The nonlinear, coupled Poisson-Boltzmann system is solved numerically using finite difference and relaxation methods. We demonstrate our method by calculating the high-temperature transport characteristics of an inhomogeneously

D. Csontos; S. E. Ulloa

2004-01-01

390

Attentional and emotional mechanisms of pain processing and their related factors: A structural equations approach  

PubMed Central

BACKGROUND/OBJECTIVE: It is known that maladaptive attentional and emotional mechanisms of pain processing – as indicated by constructs such as pain hypervigilance, pain-related anxiety and pain catastrophizing – play an important role in the development and maintenance of chronic pain conditions. However, little is known to date about the potential risk factors for these forms of maladaptive processing. The aim of the present study was to shed more light on this issue. A very comprehensive set of predictor variables was examined in healthy pain-free subjects. METHOD: Participants were 92 young and healthy subjects (mean [± SD] age 26.99±6.90 years; 47 men, 45 women). Maladaptive attentional and emotional mechanisms of pain processing were assessed by self-report measures of pain hypervigilance, pain-related anxiety and pain catastrophizing, as well as by a dot-probe task. The comprehensive set of predictor variables included measures of affective and bodily distress (depression, anxiety and somatization), experimental pain sensitivity, and cortisol reactivity. Directed relationships were estimated by using structural equation modelling. RESULTS: Structural equation modelling revealed a significant path from affective and bodily distress to self-reported maladaptive attentional and emotional pain processing. In contrast, the paths from pain sensitivity and cortisol reactivity did not reach the level of significance. CONCLUSION: These results support the position that anxiety and depression, as well as somatization, contribute to the aberrance of attentional and emotional mechanisms of pain processing. Surprisingly, the assumption of a close relationship between these maladaptive mechanisms of pain processing and pain sensitivity could not be confirmed.

Huber, Claudia; Kunz, Miriam; Artelt, Cordula; Lautenbacher, Stefan

2010-01-01

391

Construction of Questionnaires.  

National Technical Information Service (NTIS)

This is a pamphlet instructing the construction of questionnaires, as the use of questionnaires in business, industry, government, and education has increased steadily in recent years. They are used in many different areas of government operation, includi...

P. A. Duckworth

1973-01-01

392

Relativistic Wave Equations for Particles with Internal Structure and Mass Spectrum  

Microsoft Academic Search

We consider a class of wave equations which couple an infinite number of tensors or spinors of all ranks. Such a system of equations naturally possesses an infinite number of mass levels, and each eigenfunction implicitly contains a built-in form factor. Two simple examples of first order differential equations are examined. One is based on the set of all finite

Yoichiro Nambu

1966-01-01

393

Global structure in spatiotemporal chaos of the Matthews-Cox equations.  

PubMed

We find that an amplitude death state and a spatiotemporally chaotic state coexist spontaneously in the Matthews-Cox equations and this coexistence is robust. Although the entire system is far from equilibrium, the domain wall between the two states is stabilized by a negative-feedback effect due to a conservation law. This is analogous to the phase separation in conserved systems that exhibit spinodal decompositions. We observe similar phenomena also in the Nikolaevskii equation, from which the Matthews-Cox equations were derived. A Galilean invariance of the former equation corresponds to the conservation law of the latter equations. PMID:17930094

Sakaguchi, Hidetsugu; Tanaka, Dan

2007-08-13

394

The internal structure of neutron stars and white dwarfs, and the Jacobi virial equation. II.  

NASA Astrophysics Data System (ADS)

Context. The Jacobi virial equation is a very powerful tool for exploring several aspects of the stellar internal structure and evolution. In a previous paper we have shown that the function [??]GR Lambda0.9(R) is constant (?0.4) for pre main-sequence stars (PMS), white dwarfs (WD) and for some neutron star (NS) models, where ?GR and ?GR are the form-factors of the gravitational potential energy and of the moment of inertia. Aims: To investigate the structural evolution of another type of celestial bodies, we extend these calculations to gaseous planets. We also analyse the cases for which this function is not conserved during some stellar evolutionary phases. Concerning NS, we study the influence of the equation of state (EOS) on this function and refine the exponent of the auxiliary function ?(R). We also present a macroscopic criterion of stability for these stars. Methods: Non-stop calculations from the PMS to the white dwarf cooling sequences were performed with the MESA code. The covered mass range was 0.1-1.7 M?. We used the same code to compute models for gaseous planets with masses between 0.1-50 MJ. Neutron star models were computed using two codes. The first one is a modified version of the NSCool/TOV subroutines. The second code is a plain TOV solver that allows one to use seven previously described EOS. The relativistic moment of inertia and gravitational potential energy were computed through a fourth-order Runge-Kutta method. Results: By analysing the internal structure of gaseous planets we show that the function [??]GR/?0.8(R) ? ?(M,EOS) is conserved for all models during the whole planetary evolution and is independent of the planet mass. For the PMS to the white dwarf cooling sequences, we have found a connection between the strong variations of ?(M,EOS) during the intermediary evolutionary phases and the specific nuclear power. A threshold for the specific nuclear power was found. Below this limit this function is invariant (?0.4) for these models, i.e., at the initial and final stages (PMS and WD). For NS, we showed that the function ?(M,EOS) is also invariant (?0.4) and is independent of the EOS and of the stellar mass. Therefore, we confirm that regardless of the final products of the stellar evolution, NS or WD, they recover the initial value of ?(M,EOS) ? 0.4 acquired at the PMS. Finally, we have introduced a macroscopic stability criterion for NS models based on the properties of the relativistic product [??]GR.

Claret, A.; Hempel, M.

2013-04-01

395

Novel application of structural equation modeling to correlation structure analysis of CpG island methylation in colorectal cancer.  

PubMed

The CpG island methylator phenotype (CIMP-high, CIMP1) is a distinct phenotype associated with microsatellite instability (MSI) and BRAF mutation in colon cancer. Recent evidence suggests the presence of KRAS mutation-associated CIMP subtype (CIMP-low, CIMP2). We used cluster analysis, principal component analysis (PCA), and structural equation modeling (SEM), a novel strategy, to decipher the correlation structure of CpG island hypermethylation. Using a database of 861 colon and rectal cancers, DNA methylation at 16 CpG islands [CACNA1G, CDKN2A (p16/ink4a), CHFR, CRABP1, HIC1, IGF2, IGFBP3, MGMT, MINT-1, MINT-31, MLH1, NEUROG1, p14 (CDKN2A/arf), RUNX3, SOCS1, and WRN] was quantified by real-time PCR. Tumors were categorized into three groups: Group 1 with wild-type KRAS/BRAF (N = 440); Group 2 with mutant KRAS and wild-type BRAF (N = 308); and Group 3 with wild-type KRAS and mutant BRAF (N = 107). Tumors with mutant KRAS/BRAF (N = 6) were excluded. In unsupervised hierarchical clustering analysis, all but six markers (CACNA1G, IGF2, RUNX3, MGMT, MINT-1, and SOCS1) were differentially clustered with CIMP-high and CIMP-low according to KRAS and BRAF status. In SEM, the correlation structures between CIMP, locus-specific CpG island methylation, and MSI differed according to KRAS and BRAF status, which was consistent with PCA results. In conclusion, KRAS and BRAF mutations appear to differentially influence correlation structure of CpG island methylation. Our novel data suggest two distinct perturbations, resulting in differential locus-specific propensity of CpG methylation. PMID:21037082

Tanaka, Noriko; Huttenhower, Curtis; Nosho, Katsuhiko; Baba, Yoshifumi; Shima, Kaori; Quackenbush, John; Haigis, Kevin M; Giovannucci, Edward; Fuchs, Charles S; Ogino, Shuji

2010-10-29

396

Novel Application of Structural Equation Modeling to Correlation Structure Analysis of CpG Island Methylation in Colorectal Cancer  

PubMed Central

The CpG island methylator phenotype (CIMP-high, CIMP1) is a distinct phenotype associated with microsatellite instability (MSI) and BRAF mutation in colon cancer. Recent evidence suggests the presence of KRAS mutation-associated CIMP subtype (CIMP-low, CIMP2). We used cluster analysis, principal component analysis (PCA), and structural equation modeling (SEM), a novel strategy, to decipher the correlation structure of CpG island hypermethylation. Using a database of 861 colon and rectal cancers, DNA methylation at 16 CpG islands [CACNA1G, CDKN2A (p16/ink4a), CHFR, CRABP1, HIC1, IGF2, IGFBP3, MGMT, MINT-1, MINT-31, MLH1, NEUROG1, p14 (CDKN2A/arf), RUNX3, SOCS1, and WRN] was quantified by real-time PCR. Tumors were categorized into three groups: Group 1 with wild-type KRAS/BRAF (N = 440); Group 2 with mutant KRAS and wild-type BRAF (N = 308); and Group 3 with wild-type KRAS and mutant BRAF (N = 107). Tumors with mutant KRAS/BRAF (N = 6) were excluded. In unsupervised hierarchical clustering analysis, all but six markers (CACNA1G, IGF2, RUNX3, MGMT, MINT-1, and SOCS1) were differentially clustered with CIMP-high and CIMP-low according to KRAS and BRAF status. In SEM, the correlation structures between CIMP, locus-specific CpG island methylation, and MSI differed according to KRAS and BRAF status, which was consistent with PCA results. In conclusion, KRAS and BRAF mutations appear to differentially influence correlation structure of CpG island methylation. Our novel data suggest two distinct perturbations, resulting in differential locus-specific propensity of CpG methylation.

Tanaka, Noriko; Huttenhower, Curtis; Nosho, Katsuhiko; Baba, Yoshifumi; Shima, Kaori; Quackenbush, John; Haigis, Kevin M.; Giovannucci, Edward; Fuchs, Charles S.; Ogino, Shuji

2010-01-01

397

Ab initio equation of state data and interior structure of giant planets  

NASA Astrophysics Data System (ADS)

We have performed quantum molecular dynamics simulations using finite-temperature density functional theory (FT-DFT-MD) to calculate accurate equation of state data for the most abundant materials in giant planets hydrogen, helium, and water in the warm dense matter region. We discuss the phase diagram of water up to ultra-high pressures and identify the location of the superionic phase which might occur in the deep interior of Neptune, Uranus or even in Saturn. These ab initio data sets were used to calculate the interior structure models of solar giant planets within the standard three-layer model and to determine their core mass and metallicity. We have also determined possible compositions of extrasolar giant planets such as GJ 436b for which the mass-radius relation and the surface temperature are measured. We discuss also the impact of high-pressure effects such as the nonmetal-to-metal transition in hydrogen and the demixing of hydrogen and helium on the interior structure of giant planets.

Redmer, Ronald; Nettelmann, Nadine; Kramm, Ulrike; Lorenzen, Winfried; Holst, Bastian; French, Martin

2009-05-01

398

Equation of state and electronic structure of liquid Helium at high pressure  

NASA Astrophysics Data System (ADS)

As the second most abundant element, the properties of fluid Helium form an important part of our understanding of stellar and giant planetary structure. Yet the physics of Helium at pressure-temperature conditions characteristic of these bodies is uncertain. We perform first principles molecular dynamics simulations of fluid Helium over a wide range of pressure (< 1 Gbar) and temperature (< 5 eV). The simulations are based on finite-temperature density functional theory in the generalized gradient approximation, and are performed in the canonical ensemble with a Nose thermostat. We find that both temperature and compression have a strong influence on the electronic structure as revealed by the band gap. At a density of 1 g cm-3 the band gap varies from 20 eV for the static crystal to 0 for the fluid at 4 eV. The gap is closed at all temperatures for density greater than 20 g cm-3. We find that the equation of state varies smoothly through the band gap closure transition with no indication of a high-order phase transformation. The decrease in band gap with increasing temperature at constant density results from enhanced mixing of 1s- and 2s-like states with increasing disorder (i.e., enhanced vibrational amplitudes and melting) that has profound implications for understanding the deep interiors of planets.

Stixrude, Lars; Jeanloz, Raymond

2006-03-01

399

Equation of state and electronic structure of liquid Helium at high pressure  

NASA Astrophysics Data System (ADS)

As the second most abundant element, the properties of fluid Helium form an important part of our understanding of stellar and giant planetary structure. Yet the physics of Helium at pressure-temperature conditions characteristic of these bodies is uncertain. We perform first principles molecular dynamics simulations of fluid Helium over a wide range of pressure (< 1 Gbar) and temperature (< 5 eV). The simulations are based on finite-temperature density functional theory in the generalized gradient approximation, and are performed in the canonical ensemble with a Nose thermostat. We find that both temperature and compression have a strong influence on the electronic structure as revealed by the band gap. At a density of 1 g cm-3 the band gap varies from 20 eV for the static crystal to 0 for the fluid at 4 eV. The gap is closed at all temperatures for density greater than 20 g cm-3. We find that the equation of state varies smoothly through the band gap closure transition with no indication of a high-order phase transformation. The decrease in band gap with increasing temperature at constant density results from enhanced mixing of 1s- and 2s-like states with increasing disorder (i.e., enhanced vibrational amplitudes and melting) that has profound implications for understanding the deep interiors of planets.

Stixrude, Lars; Jeanloz, Raymond

2007-03-01

400

A structural equation model of plant species richness and its application to a coastal wetland  

USGS Publications Warehouse

Studies of plant species richness have often emphasized the role of either community biomass (as an indicator of density effects) or abiotic factors. In this article we present a general model that simultaneously examines the relative importance of abiotic and density effects. General and specific models were developed to examine the importance of abiotic conditions, disturbance, and community biomass on plant species richness. Models were evaluated using structural equation modeling based on data from 190 plots across a coastal marsh landscape. The accepted model was found to explain 45% of the observed variation in richness, 75% of biomass, and 65% of light penetration. Model results indicate that abiotic conditions have both direct effects on the species pool and indirect effects on richness mediated through effects on biomass and shading. Effects of disturbance were found to be indirect via biomass. Strong density effects on richness were indicated by the results, and canopy light penetration was found to be a better predictor of richness than was biomass. Overall, it appears that richness in this coastal landscape is controlled in roughly equal proportions by abiotic influences on the species pool and density effects, with disturbance playing a lesser role. The structure of the general model presented should be applicable to a wide variety of herbaceous plant communities.

Grace, J. B.; Pugesek, B. H.

1997-01-01

401

Joint modeling of intercourse behavior and human fecundability using structural equation models  

PubMed Central

Human fecundability is defined as the probability of conception during a menstrual cycle among couples at risk for pregnancy. It is highly relevant for understanding human reproduction and represents a series of highly interrelated and timed processes. The statistical literature has recognized the need to incorporate both biological and behavioral factors (Barrett and Marshall, 1969; Dunson and Stanford, 2005) when modeling conception probabilities, given that intercourse during the fertile window is a necessary but not sufficient criterion for conception. The heterogeneity of behaviors such as the timing and frequency of intercourse in a menstrual cycle needs to be considered when estimating conception. Here we propose a joint model of intercourse behavior and human fecundability through a classic conception probability model and a structural equation model (SEM) to accommodate intercourse during the menstrual cycle. The SEM part of the proposed model allows the dependency between intercourse behaviors on consecutive days in a menstrual cycle to vary across days. Consequently, the proposed model can accommodate not only a broad variety of intercourse patterns and dependency structures but also general covariate effects. Finally, we present a detailed analysis of the New York State Angler Cohort Prospective Pregnancy Study to illustrate the proposed methodology.

Kim, Sungduk; Sundaram, Rajeshwari; Buck Louis, Germaine M.

2010-01-01

402

Modeling alcohol use disorder severity: an integrative structural equation modeling approach.  

PubMed

Background: Alcohol dependence is a complex psychological disorder whose phenomenology changes as the disorder progresses. Neuroscience has provided a variety of theories and evidence for the development, maintenance, and severity of addiction; however, clinically, it has been difficult to evaluate alcohol use disorder (AUD) severity. Objective: This study seeks to evaluate and validate a data-driven approach to capturing alcohol severity in a community sample. Method: Participants were non-treatment seeking problem drinkers (n?=?283). A structural equation modeling approach was used to (a) verify the latent factor structure of the indices of AUD severity; and (b) test the relationship between the AUD severity factor and measures of alcohol use, affective symptoms, and motivation to change drinking. Results: The model was found to fit well, with all chosen indices of AUD severity loading significantly and positively onto the severity factor. In addition, the paths from the alcohol use, motivation, and affective factors accounted for 68% of the variance in AUD severity. Greater AUD severity was associated with greater alcohol use, increased affective symptoms, and higher motivation to change. Conclusion: Unlike the categorical diagnostic criteria, the AUD severity factor is comprised of multiple quantitative dimensions of impairment observed across the progression of the disorder. The AUD severity factor was validated by testing it in relation to other outcomes such as alcohol use, affective symptoms, and motivation for change. Clinically, this approach to AUD severity can be used to inform treatment planning and ultimately to improve outcomes. PMID:23908635

Moallem, Nathasha R; Courtney, Kelly E; Bacio, Guadalupe A; Ray, Lara A

2013-07-29

403

Structural equation modeling for estimating the identification accuracy and detection time latency of English monosyllabic words  

NASA Astrophysics Data System (ADS)

Structural equation modeling (SEM) was used to examine the statistical structure among sets of experiential (word age of acquisition and subjective familiarity) and lexical similarity (lexical equivalence class size and neighborhood density) variables for word identification and reaction time latency tasks. Stimuli were 240 vocoded monosyllabic English words with reduced intelligibility and altered similarity relationships. Participants detected a target word following a prime and on every trial reported the prime. The identification accuracy was estimated by words and phonemes correct, and detection latency was estimated by trimmed and harmonic mean RTs. A parsimonious SEM was chosen in terms of the chi-square and model fit indices that determine whether the models adequately described the particular associations of variables/interfactor relationships. The variable/factor error variances were constrained to be uncorrelated with each other in order to evaluate effects independently. A bootstrapping technique indicated that the regression weights of the top-down and bottom-up factors were small, but they were significant in the model. The variance accounted for (VAF) by the model was 7.1% for identification accuracy, and 5.2% for RT latency. The model also indicated that RT latency was highly influenced by prime identification accuracy (15% VAF). [Work supported by NIH/NIDCD00695.

Takayanagi, Sumiko; Bernstein, Lynne E.; Auer, Edward T.

2003-10-01

404

Next steps in Bayesian structural equation models: comments on, variations of, and extensions to Muthén and Asparouhov (2012).  

PubMed

Muthén and Asparouhov (2012) made a strong case for the advantages of Bayesian methodology in factor analysis and structural equation models. I show additional extensions and adaptations of their methods and show how non-Bayesians can take advantage of many (though not all) of these advantages by using interval restrictions on parameters. By keeping parameters restricted to intervals (such as loadings between -.3 and .3 to produce small loadings), frequentists using standard structural equation modeling software can do something similar to what a Bayesian does by putting prior distributions on these parameters. PMID:22962887

Rindskopf, David

2012-09-01

405

Factor Structure of the Primary Scales of the Inventory of Personality Organization in a Nonclinical Sample Using Exploratory Structural Equation Modeling  

ERIC Educational Resources Information Center

|Using exploratory structural equation modeling and multiple regression, we examined the factor structure and criterion relations of the primary scales of the Inventory of Personality Organization (IPO; Kernberg & Clarkin, 1995) in a nonclinical sample. Participants (N = 1,260) completed the IPO and measures of self-concept clarity, defenses,…

Ellison, William D.; Levy, Kenneth N.

2012-01-01

406

Domains of disgust sensitivity: revisited factor structure of the questionnaire for the assessment of disgust sensitivity (QADS) in a cross-sectional, representative german survey  

PubMed Central

Background Disgust sensitivity is defined as a predisposition to experiencing disgust, which can be measured on the basis of the Disgust Scale and its German version, the Questionnaire for the Assessment of Disgust Sensitivity (QADS). In various studies, different factor structures were reported for either instrument. The differences may most likely be due to the selected factor analysis estimation methods and the small non-representative samples. Consequently, the aims of this study were to explore and confirm a theory-driven and statistically coherent QADS factor structure in a large representative sample and to present its standard values. Methods The QADS was answered by N = 2473 healthy subjects. The respective households and participants were selected using the random-route sampling method. Afterwards, the collected sample was compared to the information from the Federal Statistical Office to ensure that it was representative for the German residential population. With these data, an exploratory Promax-rotated Principal Axis Factor Analysis as well as comparative confirmatory factor analyses with robust Maximum Likelihood estimations were computed. Any possible socio-demographic influences were quantified as effect sizes. Results The data-driven and theoretically sound solution with the three highly interrelated factors Animal Reminder Disgust, Core Disgust, and Contamination Disgust led to a moderate model fit. All QADS scales had very good reliabilities (Cronbach's alpha) from .90 to .95. There were no age-differences found among the participants, however, the female participants showed remarkably higher disgust ratings. Conclusions Based on the representative sample, the QADS factor structure was revised. Gender-specific standard percentages permit a population-based assessment of individual disgust sensitivity. The differences of the original QADS, the new solution, and the Disgust Scale - Revised will be discussed.

2010-01-01

407

Fear of Spiders Questionnaire  

Microsoft Academic Search

The Fear of Spiders Questionnaire (FSQ), an 18-item self-report questionnaire assessing spider phobia, was developed in an attempt to complement the information provided by the Spider Phobia Questionnaire (SPQ). Data obtained from 338 undergraduates revealed that the FSQ was able to discriminate phobics from nonphobics, and indicated decrements in phobic responding from pretest to posttest following cognitive therapy. Test-retest data,

Jeff Szymanski; William O'Donohue

1995-01-01

408

Perievent Panic Attack and Depression after the World Trade Center Disaster: A Structural Equation Model Analysis  

PubMed Central

Research suggests that perievent panic attacks – panic attacks in temporal proximity to traumatic events – are predictive of later mental health status, including the onset of depression. Using a community sample of New York City residents interviewed 1 year and 2 years after the World Trade Center Disaster, we estimated a structural equation model (SEM) using pre-disaster psychological status and post-disaster life events, together with psychosocial resources, to assess the relationship between perievent panic and later onset depression. Bivariate results revealed a significant association between perievent panic and both year-1 and year-2 depression. Results for the SEM, however, showed that perievent panic was predictive of year-1 depression, but not year-2 depression, once potential confounders were controlled. Year-2 stressors and year-2 psychosocial resources were the best predictors of year-2 depression onset. Pre-disaster psychological problems were directly implicated in year-1 depression, but not year-2 depression. We conclude that a conceptual model that includes pre- and post-disaster variables best explains the complex causal pathways between psychological status, stressor exposure, perievent panic attacks, and depression onset two years after the World Trade Center attacks.

Adams, Richard E.; Boscarino, Joseph A.

2011-01-01

409

Diagnosis Analysis of 4 TCM Patterns in Suboptimal Health Status: A Structural Equation Modelling Approach  

PubMed Central

Background. We illustrated an example of structure equation modelling (SEM) in the research on SHS to explore the diagnosis of the Sub optimal health status (SHS) and provide evidence for the standardization of traditional Chinese medicine (TCM) patterns in SHS. And the diagnosis of 4 TCM patterns in SHS was evaluated in this analysis. Methods. This study assessed data on 2807 adults (aged 18 to 49) with SHS from 6 clinical centres. SEM was used to analyze the patterns of SHS in TCM. Parameters in the introduced model were estimated by the maximum likelihood method. Results. The discussed model fits the SHS data well with CFI = 0.851 and RMSEA = 0.075. The direct effect of Qi deficiency pattern on dampness pattern had the highest magnitude (value of estimate is 0.822). With regard to the construct of “Qi deficiency pattern”, “fire pattern”, “stagnation pattern” and “dampness pattern”, the indicators with the highest load were myasthenia of limbs, vexation, deprementia, and dizziness, respectively. It had been shown that estimate factor should indicate the important degree of different symptoms in pattern. Conclusions. The weights of symptoms in the respective pattern can be statistical significant and theoretical meaningful for the 4 TCM patterns identification in SHS research. The study contributed to a theoretical framework, which has implications for the diagnosis points of SHS.

Wang, Li-Min; Zhao, Xin; Wu, Xi-Ling; Li, Yang; Yi, Dan-Hui; Cui, Hua-Ting; Chen, Jia-Xu

2012-01-01

410

Modeling motor connectivity using TMS/PET and structural equation modeling  

PubMed Central

Structural equation modeling (SEM) was applied to positron emission tomographic (PET) images acquired during transcranial magnetic stimulation (TMS) of the primary motor cortex (M1hand). TMS was applied across a range of intensities, and responses both at the stimulation site and remotely connected brain regions covaried with stimulus intensity. Regions of interest (ROIs) were identified through an activation likelihood estimation (ALE) meta-analysis of TMS studies. That these ROIs represented the network engaged by motor planning and execution was confirmed by an ALE meta-analysis of finger movement studies. Rather than postulate connections in the form of an a priori model (confirmatory approach), effective connectivity models were developed using a model-generating strategy based on improving tentatively specified models. This strategy exploited the experimentally-imposed causal relations: (1) that response variations were caused by stimulation variations, (2) that stimulation was unidirectionally applied to the M1hand region, and (3) that remote effects must be caused, either directly or indirectly, by the M1hand excitation. The path model thus derived exhibited an exceptional level of goodness (?2=22.150, df = 38, P = 0.981, TLI=1.0). The regions and connections derived were in good agreement with the known anatomy of the human and primate motor system. The model-generating SEM strategy thus proved highly effective and successfully identified a complex set of causal relationships of motor connectivity.

Laird, Angela R.; Robbins, Jacob M.; Li, Karl; Price, Larry R.; Cykowski, Matthew D.; Narayana, Shalini; Laird, Robert W.; Franklin, Crystal; Fox, Peter T.

2010-01-01

411

Predictors of falling in older Maryland drivers: a structural-equation model.  

PubMed

Falls can impair health and reduce quality of life among older adults. Although many factors are related to falling, few analyses examine causal models of this behavior. In this study, factors associated with falling were explored simultaneously using structural-equation modeling. A variety of cognitive, physical-performance, and health measures were administered to 694 older adult drivers from the state of Maryland. The observed and latent variables of age, cognitive ability, physical functioning, health, and falling behavior were used to create a causal model. The model revealed that being older was associated with declines in cognition, and such cognitive declines predicted increased falling. Similarly, poorer health was related to poorer physical functioning, which, in turn, also predicted increased falling. This model indicates that in addition to existing fall-prevention interventions aimed at improving physical functioning, interventions to improve cognition and health might also be effective. It is speculated that fear of falling, which often results in reduced mobility among older adults, might account for the lack of a direct relationship between age and falling. This hypothesis should be examined in further research. PMID:17090804

Vance, David E; Ball, Karlene K; Roenker, Daniel L; Wadley, Virginia G; Edwards, Jerri D; Cissell, Gayla M

2006-07-01

412

Identifying determinants of nations' wetland management programs using structural equation modeling: An exploratory analysis  

USGS Publications Warehouse

Integrated management and policy models suggest that solutions to environmental issues may be linked to the socioeconomic and political Characteristics of a nation. In this study, we empirically explore these suggestions by applying them to the wetland management activities of nations. Structural equation modeling was used to evaluate a model of national wetland management effort and one of national wetland protection. Using five predictor variables of social capital, economic capital, environmental and political characteristics, and land-use pressure, the multivariate models were able to explain 60% of the variation in nations' wetland protection efforts based on data from 90 nations, as defined by level of participation, in the international wetland convention. Social capital had the largest direct effect on wetland protection efforts, suggesting that increased social development may eventually lead to better wetland protection. In contrast, increasing economic development had a negative linear relationship with wetland protection efforts, suggesting the need for explicit wetland protection programs as nations continue to focus on economic development. Government, environmental characteristics, and land-use pressure also had a positive direct effect on wetland protection, and mediated the effect of social capital on wetland protection. Explicit wetland protection policies, combined with a focus on social development, would lead to better wetland protection at the national level.

La, Peyre, M. K.; Mendelssohn, I. A.; Reams, M. A.; Templet, P. H.; Grace, J. B.

2001-01-01

413

Otitis media, fluctuant hearing loss, and speech-language outcomes: a preliminary structural equation model.  

PubMed

The goals of this study were to estimate the risk for lowered speech-language outcomes associated with early recurrent otitis media with effusion (OME) with and without hearing loss and to develop a preliminary descriptive-explanatory model for the findings. Three statistical approaches were used to assess associations among OME, hearing loss, and speech-language outcomes. Participants were a subsample of 70 children followed prospectively in the Dallas Cooperative Project on Early Hearing and Language Development (Friel-Patti & Finitzo, 1990). Findings indicated that hearing levels at 12-18 months were significantly associated with speech delay and low language outcomes at 3 years of age. The risk for subclinical or clinical speech delay at 3 years of age was 2% for children with less than 20 dB average hearing levels at 12-18 months and 33% for children with greater than 20 dB average hearing levels at 12-18 months. A structural equation model (Jöreskog & Sörbom, 1993) indicated that the significant and substantial effects of hearing levels at 12-18 months on speech status at 3 years were significantly mediated by language status at 3 years. Discussion includes implications of these findings for alternative speech perception models linking early OME and hearing loss to later speech-language disorder. PMID:10668655

Shriberg, L D; Friel-Patti, S; Flipsen, P; Brown, R L

2000-02-01

414

A structural equation model of the developmental origins of blood pressure  

PubMed Central

Background Birth-size is a problematic proxy for the fetal environment, and regression models testing for associations between birth-size and blood pressure have been criticized. Methods We modelled fetal environment as a latent variable determined by maternal height and arm fat area (AFA) during pregnancy using structural equation modelling. We tested for associations between latent fetal environment (LFE) and systolic blood pressure (SBP) while controlling for birth weight (BW) and current weight (CW). Data are from 1435 male and 1218 female young adult Filipinos (2005; mean age 21 years) enrolled in the Cebu Longitudinal Heath and Nutrition Survey, an ongoing, community-based study of a one-year birth cohort. Using AMOS 6.0, LFE was modelled as a determinant of BW, CW and SBP; CW was modelled as a determinant of SBP. Results Overall model fit was excellent (?2: 32.14, 27 df, P = 0.23). The estimated direct relationship between LFE and SBP was inverse for both males (?0.43 ?0.26 ?0.10) and females (?0.29 ?0.18 ?0.07). Conclusions These results are consistent with the hypothesis that maternal height and AFA impact fetal development in a manner that is positively associated with fetal growth (as reflected by BW) and inversely associated with SBP in young adulthood.

Dahly, D L; Adair, LS; Bollen, KA

2009-01-01

415

Predicting adolescent asthma research participation decisions from a structural equations model of protocol factors  

PubMed Central

Purpose To examine similarities and differences in the process that parents and adolescents use to make decisions concerning participation in an asthma clinical trial. We hypothesized that a single conceptual model, tested through structural equations modeling, could explain adolescent assent and parent consent for adolescent research participation. Methods 109 adolescents enrolled with at least one parent and received an asthma evaluation from a pediatric asthma specialist and then evaluated a hypothetical asthma research protocol. Family members independently evaluated the protocol and made research participation decisions. Results Perceived risk, benefit and compensation were direct predictors of participation decisions for parents and adolescents. Adolescents perceived direct study benefit from the relationship with the physician, however parents did not. Parent decisions were most strongly associated with perceived risk, and parents associated discomfort with risk more strongly than did adolescents. Protocol procedures contributed to perceptions of benefit and discomfort for parents and adolescents. Conclusions Parent and adolescent research participation decisions are influenced by protocol variables in similar ways, although there are differences that account for disagreements within families. Findings may help investigators develop protocols that appeal to parents and adolescents and highlight issues of particular importance to address during the process of informed consent.

Brody, Janet L.; Turner, Charles; Annett, Robert D.; Scherer, David G.; Dalen, Jeanne

2012-01-01

416

Diagnosis Analysis of 4 TCM Patterns in Suboptimal Health Status: A Structural Equation Modelling Approach.  

PubMed

Background. We illustrated an example of structure equation modelling (SEM) in the research on SHS to explore the diagnosis of the Sub optimal health status (SHS) and provide evidence for the standardization of traditional Chinese medicine (TCM) patterns in SHS. And the diagnosis of 4 TCM patterns in SHS was evaluated in this analysis. Methods. This study assessed data on 2807 adults (aged 18 to 49) with SHS from 6 clinical centres. SEM was used to analyze the patterns of SHS in TCM. Parameters in the introduced model were estimated by the maximum likelihood method. Results. The discussed model fits the SHS data well with CFI = 0.851 and RMSEA = 0.075. The direct effect of Qi deficiency pattern on dampness pattern had the highest magnitude (value of estimate is 0.822). With regard to the construct of "Qi deficiency pattern", "fire pattern", "stagnation pattern" and "dampness pattern", the indicators with the highest load were myasthenia of limbs, vexation, deprementia, and dizziness, respectively. It had been shown that estimate factor should indicate the important degree of different symptoms in pattern. Conclusions. The weights of symptoms in the respective pattern can be statistical significant and theoretical meaningful for the 4 TCM patterns identification in SHS research. The study contributed to a theoretical framework, which has implications for the diagnosis points of SHS. PMID:22550544

Wang, Li-Min; Zhao, Xin; Wu, Xi-Ling; Li, Yang; Yi, Dan-Hui; Cui, Hua-Ting; Chen, Jia-Xu

2012-04-10

417

Testing hypotheses in evolutionary ecology with imperfect detection: capture-recapture structural equation modeling.  

PubMed

Studying evolutionary mechanisms in natural populations often requires testing multifactorial scenarios of causality involving direct and indirect relationships among individual and environmental variables. It is also essential to account for the imperfect detection of individuals to provide unbiased demographic parameter estimates. To cope with these issues, we developed a new approach combining structural equation models with capture-recapture models (CR-SEM) that allows the investigation of competing hypotheses about individual and environmental variability observed in demographic parameters. We employ Markov chain Monte Carlo sampling in a Bayesian framework to (1) estimate model parameters, (2) implement a model selection procedure to evaluate competing hypotheses about causal mechanisms, and (3) assess the fit of models to data using posterior predictive checks. We illustrate the value of our approach using two case studies on wild bird populations. We first show that CR-SEM can be useful to quantify the action of selection on a set of phenotypic traits with an analysis of selection gradients on morphological traits in Common Blackbirds (Turdus merula). In a second case study on Blue Tits (Cyanistes caeruleus), we illustrate the use of CR-SEM to study evolutionary trade-offs in the wild, while accounting for varying environmental conditions. PMID:22624306

Cubaynes, Sarah; Doutrelant, Claire; Grégoire, Arnaud; Perret, Philippe; Faivre, Bruno; Gimenez, Olivier

2012-02-01

418

Lifestyle behavior change and repeat health risk appraisal participation: a structural equation modeling approach.  

PubMed

Abstract Purpose. Health risk appraisals (HRAs) have been used to address multiple health concerns and lifestyle behaviors. We explore the longitudinal relationship between emotional health, stage of change for five lifestyle behaviors, and lifestyle risks using HRA-generated data. Design. Secondary analysis of 3 years of HRA data. Setting. A large health care management services provider. Subjects. A total of 7535 adults employed across three companies who completed consecutive HRAs over a 3-year period. Measures. Self-report items concerning participant health, lifestyle behaviors, disease risk factors, job/life satisfaction, safety, and biometrics. Analysis. Structural equation modeling tested a hypothesized longitudinal, fully cross-lagged panel design. Results. Results indicated that greater numbers of physical and behavioral risks classified as high risk were associated with greater intention to change or an actual change in lifestyle behavior in the following year. In addition, poorer emotional health was associated with a higher number of risks. Conclusion. Data from repeat participation in HRAs can be useful in studying multiple risk behaviors and related health measures, supporting the design and evaluation of effective, individualized, and responsive health promotion activities for working adults. PMID:23621625

Simpson, Vicki L; Hyner, Gerald C; Anderson, James G

2013-04-26

419

Structural equation modeling of the inflammatory response to traffic air pollution.  

PubMed

Several epidemiological studies have reported conflicting results on the effect of traffic-related pollutants on markers of inflammation. In a Bayesian framework, we examined the effect of traffic pollution on inflammation using structural equation models (SEMs). We studied measurements of C-reactive protein (CRP), soluble vascular cell adhesion molecule-1 (sVCAM-1), and soluble intracellular adhesion molecule-1 (sICAM-1) for 749 elderly men from the Normative Aging Study. Using repeated measures SEMs, we fit a latent variable for traffic pollution that is reflected by levels of black carbon, carbon monoxide, nitrogen monoxide and nitrogen dioxide to estimate its effect on a latent variable for inflammation that included sICAM-1, sVCAM-1 and CRP. Exposure periods were assessed using 1-, 2-, 3-, 7-, 14- and 30-day moving averages previsit. We compared our findings using SEMs with those obtained using linear mixed models. Traffic pollution was related to increased inflammation for 3-, 7-, 14- and 30-day exposure periods. An inter-quartile range increase in traffic pollution was associated with a 2.3% (95% posterior interval (PI): 0.0-4.7%) increase in inflammation for the 3-day moving average, with the most significant association observed for the 30-day moving average (23.9%; 95% PI: 13.9-36.7%). Traffic pollution adversely impacts inflammation in the elderly. SEMs in a Bayesian framework can comprehensively incorporate multiple pollutants and health outcomes simultaneously in air pollution-cardiovascular epidemiological studies. PMID:23232970

Baja, Emmanuel S; Schwartz, Joel D; Coull, Brent A; Wellenuis, Gregory A; Vokonas, Pantel S; Suh, Helen H

2012-12-12

420

Analysis of Roadside Air Quality in Jakarta City: A Structural Equation Approach  

NASA Astrophysics Data System (ADS)

Jakarta city has serious air pollution problems which largely affected by transportation activities. In this paper, a comparative analysis of ambient roadside air pollution patterns in Jakarta city was conducted by using time series data at the existing roadside monitoring stations in 2003. The complex cause-effect relationships between meteorology and pollutants, thus, differ from one season to another. This paper attempts to apply structural equation models with latent variables, which represents the above-mentioned cause-effect relationships. The effectiveness of the established models is empirically confirmed that the goodness-of-fit indices are 0.783 for the weekday wet, 0.845 for the weekday dry, 0.775 for the weekend wet, and 0.822 for the weekend dry. The models give us a better way to analyze urban air pollution due to the results of the significant interactions among meteorological factors, wind and primary pollutants, and also their different influences on surface ozone for each season.

Nugroho, Sudarmanto Budi; Fujiwara, Akimasa; Zhang, Junyi

421

Perievent panic attack and depression after the World Trade Center disaster: a structural equation model analysis.  

PubMed

Research suggests that perievent panic attacks--panic attacks in temporal proximity to traumatic events--are predictive of later mental health status, including the onset of depression. Using a community sample of New York City residents interviewed 1 year and 2 years after the World Trade Center Disaster, we estimated a structural equation model (SEM) using pre-disaster psychological status and post-disaster life events, together with psychosocial resources, to assess the relationship between perievent panic and later onset depression. Bivariate results revealed a significant association between perievent panic and both year-1 and year-2 depression. Results for the SEM, however showed that perievent panic was predictive of year-1 depression, but not year-2 depression, once potential confounders were controlled Year-2 stressors and year-2 psychosocial resources were the best predictors of year-2 depression onset. Pre-disaster psychological problems were directly implicated in year-1 depression, but not year-2 depression. We conclude that a conceptual model that includes pre- and post-disaster variables best explains the complex causal pathways between psychological status, stressor exposure, perievent panic attacks, and depression onset two years after the World Trade Center attacks. PMID:21957721

Adams, Richard E; Boscarino, Joseph A

2011-01-01

422

Determinants of primary care physicians' referral pattern: a structural equation model approach.  

PubMed

This study examines patient referrals by primary care physicians (PCP) with nurse practitioners and physician assistants (NP-PA) in their medical practices as compared to practices without them. The study uses data from the Robert Wood Johnson Foundation community tracking study (CTS) Physician Survey, Round I (1996-97) and II (1998-99). Structural equations with binary dependent variables were used to examine the links among managed care, the use of NP-PA, the complexity of patient's conditions, and the number of referrals. PCP's with NP-PA were found to have a greater likelihood of treating patients with complex conditions instead of referring them to specialists. Managed care related variables (i.e., large group practice/HMO, the percentage of patients for whom PCPs acted as gatekeepers, and the percentage of managed care revenue from capitated/prepaid contracts) affected PCP' patient referrals, but only through the increased use of NP-PA. PCP's with NP-PA were also found to provide appropriate care to the complex patients. These findings indicate that NP-PA enable PCP to concentrate on patients with more complex conditions thus reducing the number of referrals. In addition, NP-PA is found to affect the gatekeeper role of PCPs. PMID:20351790

Chung, Kyusuk; Yang, Duckhye; Lee, Jun Hyup

2010-01-01

423

A GENERAL PANEL MODEL WITH RANDOM AND FIXED EFFECTS: A STRUCTURAL EQUATIONS APPROACH  

PubMed Central

Fixed and random effects models for longitudinal data are common in sociology. Their primary advantage is that they control for time-invariant omitted variables. However, analysts face several issues when they employ these models. One is the uncertainty of whether to apply the fixed effects (FEM) versus the random effects (REM) models. Another less discussed issue is that the FEM and REM models as usually implemented might be insufficiently flexible. For instance, the effects of variables, including the latent time-invariant variable, might change over time rather than be constant as in the usual FEM and REM. The latent time-invariant variable might correlate with some variables and not others. Lagged endogenous variables might be necessary. Alternatives that move beyond the classic FEM and REM models are known, but they involve different estimators and software that make these extended models difficult to implement and to compare. This paper presents a general panel model that includes the standard FEM and REM as special cases. In addition, it provides a sequence of nested models that provide a richer range of models that researchers can easily compare with likelihood ratio tests and fit statistics. Furthermore, researchers can implement our general panel model and its special cases in widely available structural equation models (SEMs) software. The paper is oriented towards applied researchers with most technical details given in the appendix and footnotes. An extended empirical example illustrates our results.

Bollen, Kenneth A.; Brand, Jennie E.

2011-01-01

424

A unified equation of state of dense matter and neutron star structure  

NASA Astrophysics Data System (ADS)

An equation of state (EOS) of neutron star matter, describing both the neutron star crust and the liquid core, is calculated. It is based on the effective nuclear interaction SLy of the Skyrme type, which is particularly suitable for the application to the calculation of the properties of very neutron rich matter (Chabanat et al. 1997, 1998). The structure of the crust, and its EOS, is calculated in the T=0 approximation, and under the assumption of the ground state composition. The crust-core transition is a very weakly first-order phase transition, with relative density jump of about one percent. The EOS of the liquid core is calculated assuming (minimal) npemu composition. Parameters of static neutron stars are calculated and compared with existing observational data on neutron stars. The minimum and maximum masses of static neutron stars are 0.094 Msun and 2.05 Msun, respectively. Effects of rotation on the minimum and the maximum mass of neutron stars are briefly discussed.

Douchin, F.; Haensel, P.

2001-12-01

425

A Model for Integrating Fixed-, Random-, and Mixed-Effects Meta-Analyses into Structural Equation Modeling  

ERIC Educational Resources Information Center

|Meta-analysis and structural equation modeling (SEM) are two important statistical methods in the behavioral, social, and medical sciences. They are generally treated as two unrelated topics in the literature. The present article proposes a model to integrate fixed-, random-, and mixed-effects meta-analyses into the SEM framework. By applying an…

Cheung, Mike W.-L.

2008-01-01

426

Doubly-Latent Models of School Contextual Effects: Integrating Multilevel and Structural Equation Approaches to Control Measurement and Sampling Error  

ERIC Educational Resources Information Center

|This article is a methodological-substantive synergy. Methodologically, we demonstrate latent-variable contextual models that integrate structural equation models (with multiple indicators) and multilevel models. These models simultaneously control for and unconfound measurement error due to sampling of items at the individual (L1) and group (L2)…

Marsh, Herbert W.; Ludtke, Oliver; Robitzsch, Alexander; Trautwein, Ulrich; Asparouhov, Tihomir; Muthen, Bengt; Nagengast, Benjamin

2009-01-01

427

Do Test Design and Uses Influence Test Preparation? Testing a Model of Washback with Structural Equation Modeling  

ERIC Educational Resources Information Center

|This study introduces Expectancy-value motivation theory to explain the paths of influences from perceptions of test design and uses to test preparation as a special case of washback on learning. Based on this theory, two conceptual models were proposed and tested via Structural Equation Modeling. Data collection involved over 870 test takers of…

Xie, Qin; Andrews, Stephen

2013-01-01

428

The Impact of Nonnormality on Full Information Maximum-Likelihood Estimation for Structural Equation Models With Missing Data  

Microsoft Academic Search

A Monte Carlo simulation examined full information maximum-likelihood estimation (FIML) in structural equation models with nonnormal indicator variables. The impacts of 4 independent variables were examined (missing data algorithm, missing data rate, sample size, and distribution shape) on 4 outcome measures (parameter estimate bias, parameter estimate efficiency, standard error coverage, and model rejection rates). Across missing completely at random and

Craig K. Enders

2001-01-01

429

A Note on the Use of Missing Auxiliary Variables in Full Information Maximum Likelihood-Based Structural Equation Models  

ERIC Educational Resources Information Center

Recent missing data studies have argued in favor of an "inclusive analytic strategy" that incorporates auxiliary variables into the estimation routine, and Graham (2003) outlined methods for incorporating auxiliary variables into structural equation analyses. In practice, the auxiliary variables often have missing values, so it is reasonable to…

Enders, Craig K.

2008-01-01

430

Maximum Likelihood Methods in Treating Outliers and Symmetrically Heavy-Tailed Distributions for Nonlinear Structural Equation Models with Missing Data  

ERIC Educational Resources Information Center

|By means of more than a dozen user friendly packages, structural equation models (SEMs) are widely used in behavioral, education, social, and psychological research. As the underlying theory and methods in these packages are vulnerable to outliers and distributions with longer-than-normal tails, a fundamental problem in the field is the…

Lee, Sik-Yum; Xia, Ye-Mao

2006-01-01

431

Accuracy in Parameter Estimation for Targeted Effects in Structural Equation Modeling: Sample Size Planning for Narrow Confidence Intervals  

ERIC Educational Resources Information Center

|In addition to evaluating a structural equation model (SEM) as a whole, often the model parameters are of interest and confidence intervals for those parameters are formed. Given a model with a good overall fit, it is entirely possible for the targeted effects of interest to have very wide confidence intervals, thus giving little information…

Lai, Keke; Kelley, Ken

2011-01-01

432

Next Steps in Bayesian Structural Equation Models: Comments on, Variations of, and Extensions to Muthen and Asparouhov (2012)  

ERIC Educational Resources Information Center

Muthen and Asparouhov (2012) made a strong case for the advantages of Bayesian methodology in factor analysis and structural equation models. I show additional extensions and adaptations of their methods and show how non-Bayesians can take advantage of many (though not all) of these advantages by using interval restrictions on parameters. By…

Rindskopf, David

2012-01-01

433

A Patient Satisfaction Theory and Its Robustness Across Gender in Emergency Departments: A Multigroup Structural Equation Modeling Investigation  

Microsoft Academic Search

This investigation tested the patient-centered Primary Provider Theory of Patient Satisfaction across gender in national random samples of emergency patients. Using multigroup structural equation modeling, the results supported the model's robustness. Physician service, waiting time, and nursing satisfaction explained 48%, 41%, and 11% of overall satisfaction plus 92% and 93% of female and male satisfaction, respectively. Unit increases in physician

Stephen J. Aragon; Sabina B. Gesell

2003-01-01

434

Next Steps in Bayesian Structural Equation Models: Comments on, Variations of, and Extensions to Muthén and Asparouhov (2012)  

Microsoft Academic Search

Muthén and Asparouhov (2012) made a strong case for the advantages of Bayesian methodology in factor analysis and structural equation models. I show additional extensions and adaptations of their methods and show how non-Bayesians can take advantage of many (though not all) of these advantages by using interval restrictions on parameters. By keeping parameters restricted to intervals (such as loadings

David Rindskopf

2012-01-01

435

A Structural Equation Modeling Approach for the Analysis of Cortisol Data Collected Using Pre-Post-Post Designs  

ERIC Educational Resources Information Center

|This study introduces a novel application of structural equation modeling (SEM) for the analysis of cortisol data that are collected using a pre-post-post design. By way of an extended example, an SEM model is developed that permits an examination of both the overall level of cortisol, as well as changes in cortisol (reactivity and regulation),…

Willoughby, Michael; Vandergrift, Nathan; Blair, Clancy; Granger, Douglas A.

2007-01-01

436

Personality, Self-Estimated Intelligence, and Uses of Music: A Spanish Replication and Extension Using Structural Equation Modeling  

Microsoft Academic Search

This study replicates and extends a recent study on personality, intelligence and uses of music [Chamorro-Premuzic, T., & Furnham, A. (2007). Personality and music: Can traits explain how people use music in everyday life? British Journal of Psychology, 98, 175–185] using Spanish participants and structural equation modeling. Data from 245 university students showed that, in line with our hypotheses, individuals

Tomas Chamorro-Premuzic; Montserrat Gomà-i-Freixanet; Adrian Furnham; Anna Muro

2009-01-01

437

Hamiltonian Structure of Benney Type Hydrodynamic and Boltzmann-Vlasov Kinetic Equations on an Axis and Some Applications to Manufacturing Science  

Microsoft Academic Search

Some years ago Zakharov and Gibbon observed a very nice relation between the Benney type equation in hydrodynamics and the Vlasov equation of kinetic theory. These equations are generalized and put into the framework of infinite-dimensional Lie algebras associated to Lie algebra structures on rings of functions on finite-dimensional manifolds. This gives rise to a complete description of the Hamiltonian

A. Prykarpatsky; D. Blackmore; N. N. Bogoliubov

1999-01-01

438

DirectLiNGAM: A direct method for learning a linear non-Gaussian structural equation model  

Microsoft Academic Search

Structural equation models and Bayesian networks have been widely used to analyze causal relations between continuous variables. In such frameworks, linear acyclic models are typically used to model the data-generating process of variables. Recently, it was shown that use of non-Gaussianity identifies the full structure of a linear acyclic model, i.e., a causal ordering of variables and their connection strengths,

Shohei Shimizu; Takanori Inazumi; Yasuhiro Sogawa; Aapo Hyvarinen; Yoshinobu Kawahara; Takashi Washio; Patrik O. Hoyer; Kenneth Bollen

2011-01-01

439

Self-preservation of large-scale structures in a nonlinear viscous medium described by the Burgers equation  

Microsoft Academic Search

We use the asymptotic solution of the one-dimensional Burgers equation to study the self-preservation of large-scale random\\u000a structures. We show that in the process of their evolution, large-scale structures remain stable against small-scale perturbations\\u000a for the case of a continuous initial spectrum with a spectral index smaller than unity. We study both analytically and numerically\\u000a the correlation coefficient of a

S. N. Gurbatov; G. V. Pasmanik

1999-01-01

440

Generalized volume-surface integral equation for modeling inhomogeneities within high contrast composite structures  

Microsoft Academic Search

Numerical solutions of volume integral equations with high contrast inhomogeneous materials require extremely fine discretization rates making their utility very limited. Given the application of such materials for antennas and metamaterials, it is extremely important to explore computationally efficient modeling methods. In this paper, we propose a novel volume integral equation technique where the domain is divided into different material

Brian C. Usner; Kubilay Sertel; Michael A. Carr; John L. Volakis

2006-01-01

441

Finite-dimensional quasi-Hamiltonian structure in simple model equations  

Microsoft Academic Search

Summary A simple systematic method has been developed to investigate the laws of conservation for approximating model equations. The main purpose of this paper is to identify these model equations as approximations of continuous Hamiltonian systems. If this identification is possible, the laws of conservation of the model system can be investigated as for a finite dimensional Hamiltonian system. Obviously,

István Szynyogh

1993-01-01

442

New travelling wave solutions of different physical structures to generalized BBM equation  

NASA Astrophysics Data System (ADS)

New ansatze that involve hyperbolic functions are introduced to handle the generalized Benjamin Bona Mahony (BBM) equation. The tanh sech method and the sine cosine method are applied as well. A set of new solitons, kinks, and periodic solutions is formally established. The work introduces useful guidance for other related nonlinear evolution equations.

Wazwaz, Abdul-Majid

2006-07-01

443

Questionnaire for Parents.  

ERIC Educational Resources Information Center

|The 116-item parent questionnaire is designed for parents of elementary school children. It is intended to be used with the child's mother, or the person acting as the child's mother. The questionnaire consists of a section devoted to demographic variables and scales measuring 14 parent variables: (1) parent's achievement aspirations for the…

Purdue Univ., Lafayette, IN. Educational Research Center.

444

Improving Food Frequency Questionnaires  

Microsoft Academic Search

In an attempt to improve data quality and ease of administration of standard self-administered food frequency questionnaires, various alternative approaches were tried for inquiring about frequency of consumption, portion size, seasonal intake, and food preparation. Evaluation consisted of a cognitive interviewing method in which respondents verbalize their thought process while completing several variations of a questionnaire. Interviewers observed and asked

AMY F SUBAR; FRANCES E THOMPSON; ALBERT F SMITH; JARED B JOBE; REGINA G ZIEGLER; NANCY POTISCHMAN; ARTHUR SCHATZKIN; ANNE HARTMAN; CHRISTINE SWANSON; LAURA KRUSE; RICHARD B HAYES; DENISE RIEDEL LEWIS; LINDA C HARLAN

1995-01-01

445

Cognitive processes in university learning: a developmental framework using structural equation modelling.  

PubMed

BACKGROUND. Both achievement goals and study processing strategies theories have been shown to contribute to the prediction of students' academic performance. Existing research studies (Fenollar, Román, & Cuestas, 2007; Liem, Lau, & Nie, 2008; Simons, Dewitte, & Lens, 2004) amalgamating these two theoretical orientations in different causal models have reported their associations with other adaptive strategies and motivational constructs - for example, effort expenditure. Despite this recognition, there have been to date very few studies that explored the relations between achievement goals, study processing strategies, effort, and academic performance over time. AIM OF STUDY. The primary focus of our study is to explore the relations between the aforementioned theoretical constructs over a 2-year period. Specifically, we tested an empirical model that conceptualized the relations between performance-approach and mastery goals, deep processing strategies, effort, and academic performance across six time points of data collection. METHODOLOGY. Two hundred and eighty-one (161 females, 120 males) university students took part in this study. The participants were administered various Likert-scale inventories and the overall course mark and final examination were used as indexes of academic performance. RESULTS. Structural equation modelling indicated a relatively good fit to the a posteriori model and the hypothesized paths were, in part, supported. The major findings included the predictive effects of performance-approach goals at Time 1 on deep processing strategies at Time 2 and mastery goals at Time 3; the predictive effect of mastery goals at Time 3 on effort at Time 4; the predictive effects of deep processing at Time 2 on mastery goals at Time 3 and Time 4. Furthermore, the placement of deep processing and effort in this structural model also accentuated the performance-approach goals - mastery goals - effort - academic performance relation, and the performance-approach goals - deep processing - mastery goals - effort - academic performance relation. DISCUSSION. Our study has important theoretical and practical implications concerning the conceptualization of the performance-approach and mastery goals relationship, and the use of goal structure and adaptive strategies (e.g., deep processing) to enhance academic learning. PMID:21199483

Phan, Huy P

2010-11-18

446

Structural equation modeling of the proximal-distal continuum of adherence drivers  

PubMed Central

Objectives Nonadherence to prescription medications has been shown to be significantly influenced by three key medication-specific beliefs: patients’ perceived need for the prescribed medication, their concerns about the prescribed medication, and perceived medication affordability. Structural equation modeling was used to test the predictors of these three proximal determinants of medication adherence using the proximal–distal continuum of adherence drivers as the organizing conceptual framework. Methods In Spring 2008, survey participants were selected from the Harris Interactive Chronic Illness Panel, an internet-based panel of hundreds of thousands of adults with chronic disease. Respondents were eligible for the survey if they were aged 40 years and older, resided in the US, and reported having at least one of six chronic diseases: asthma, diabetes, hyperlipidemia, hypertension, osteoporosis, or other cardiovascular disease. A final sample size of 1072 was achieved. The proximal medication beliefs were measured by three multi-item scales: perceived need for medications, perceived medication concerns, and perceived medication affordability. The intermediate sociomedical beliefs and skills included four multi-item scales: perceived disease severity, knowledge about the prescribed medication, perceived immunity to side effects, and perceived value of nutraceuticals. Generic health beliefs and skills consisted of patient engagement in their care, health information-seeking tendencies, internal health locus of control, a single-item measure of self-rated health, and general mental health. Structural equation modeling was used to model proximal–distal continuum of adherence drivers. Results The average age was 58 years (range = 40–90 years), and 65% were female and 89% were white. Forty-one percent had at least a four-year college education, and just under half (45%) had an annual income of $50,000 or more. Hypertension and hyperlipidemia were each reported by about a quarter of respondents (24% and 23%, respectively). A smaller percentage of respondents had osteoporosis (17%), diabetes (15%), asthma (13%), or other cardiovascular disease (8%). Three independent variables were significantly associated with the three proximal adherence drivers: perceived disease severity, knowledge about the medication, and perceived value of nutraceuticals. Both perceived immunity to side effects and patient engagement was significantly associated with perceived need for medications and perceived medication concerns. Conclusion Testing the proximal–distal continuum of adherence drivers shed light on specific areas where adherence dialogue and enhancement should focus. Our results can help to inform the design of future adherence interventions as well as the content of patient education materials and adherence reminder letters. For long-term medication adherence, patients need to autonomously and intrinsically commit to therapy and that, in turn, is more likely to occur if they are both informed (disease and medication knowledge and rationale, disease severity, consequences of nonadherence, and side effects) and motivated (engaged in their care, perceive a need for medication, and believe the benefits outweigh the risks).

McHorney, Colleen A; Zhang, Ning Jackie; Stump, Timothy; Zhao, Xiaoquan

2012-01-01

447

Smoking behaviours and cessation services among male physicians in China: evidence from a structural equation model  

PubMed Central

Objective To investigate smoking prevalence and cessation services provided by male physicians in hospitals in three Chinese cities. Methods Data were collected from a survey of male physicians employed at 33 hospitals in Changsha, Qingdao and Wuxi City (n=720). Exploratory factor analysis was performed to identify latent variables, and confirmatory structural equation modelling analysis was performed to test the relationships between predictor variables and smoking in male physicians, and their provision of cessation services. Results Of the sampled male physicians, 25.7% were current smokers, and 54.0% provided cessation services by counselling (18.8%), distributing self-help materials (17.1%), and providing traditional remedies or medication (18.2%). Factors that predicted smoking included peer smoking (OR 1.14 95% CI 1.03 to 1.26) and uncommon knowledge (OR 0.94 95% CI 0.89 to 0.99), a variable measuring awareness of the association of smoking with stroke, heart attack, premature ageing and impotence in male adults as well as the role of passive smoking in heart attack. Factors that predicted whether physicians provided smoking cessation services included peer smoking (OR 0.82 95% CI 0.76 to 0.89), physicians’ own smoking (OR 0.87 95% CI 0.81 to 0.93), training in cessation (OR 1.36 95% CI 1.27 to 1.45) and access to smoking cessation resources (OR 1.69 95% CI 1.58 to 1.82). Conclusions The smoke-free policy is not strictly implemented at healthcare facilities, and smoking remains a public health problem among male physicians. A holistic approach, including a stricter implementation of the smoke-free policy, comprehensive education on the hazards of smoking, training in standard smoking-cessation techniques and provision of cessation resources, is needed to curb the smoking epidemic among male physicians and to promote smoking cessation services in China.

Huang, Cheng; Guo, Chaoran; Yu, Shaohua; Feng, Yan; Song, Julia; Eriksen, Michael; Redmon, Pam; Koplan, Jeffrey

2013-01-01

448

Relationships between hormones and aggressive behavior in green anole lizards: an analysis using structural equation modeling.  

PubMed

We investigated the relationship between aggressive behavior and circulating androgens in the context of agonistic social interaction and examined the effect of this interaction on the androgen-aggression relationship in response to a subsequent social challenge in male Anolis carolinensis lizards. Individuals comprising an aggressive encounter group were exposed to an aggressive conspecific male for 10 min per day during a 5-day encounter period, while controls were exposed to a neutral stimulus for the same period. On the sixth day, their responses to an intruder test were observed. At intervals, individuals were sacrificed to monitor plasma androgen levels. Structural equation modeling (SEM) was used to test three a priori interaction models of the relationship between social stimulus, aggressive behavior, and androgen. Model 1 posits that exposure to a social stimulus influences androgen and aggressive behavior independently. In Model 2, a social stimulus triggers aggressive behavior, which in turn increases circulating levels of androgen. In Model 3, exposure to a social stimulus influences circulating androgen levels, which in turn triggers aggressive behavior. During the 5 days of the encounter period, circulating testosterone (T) levels of the aggressive encounter group followed the same pattern as their aggressive behavioral responses, while the control group did not show significant changes in their aggressive behavior or T level. Our SEM results supported Model 2. A means analysis showed that during the intruder test, animals with 5 days of aggressive encounters showed more aggressive responses than did control animals, while their circulating androgen levels did not differ. This further supports Model 2, suggesting that an animal's own aggressive behavior may trigger increases in levels of plasma androgen. PMID:12367572

Yang, Eun-Jin; Wilczynski, Walter

2002-09-01

449

A Structural Equation Model Analysis of Relationships among ENSO, Seasonal Descriptors and Wildfires  

PubMed Central

Seasonality drives ecological processes through networks of forcings, and the resultant complexity requires creative approaches for modeling to be successful. Recently ecologists and climatologists have developed sophisticated methods for fully describing seasons. However, to date the relationships among the variables produced by these methods have not been analyzed as networks, but rather with simple univariate statistics. In this manuscript we used structural equation modeling (SEM) to analyze a proposed causal network describing seasonality of rainfall for a site in south-central Florida. We also described how this network was influenced by the El Niño-Southern Oscillation (ENSO), and how the network in turn affected the site’s wildfire regime. Our models indicated that wet and dry seasons starting later in the year (or ending earlier) were shorter and had less rainfall. El Niño conditions increased dry season rainfall, and via this effect decreased the consistency of that season’s drying trend. El Niño conditions also negatively influenced how consistent the moistening trend was during the wet season, but in this case the effect was direct and did not route through rainfall. In modeling wildfires, our models showed that area burned was indirectly influenced by ENSO via its effect on dry season rainfall. Area burned was also indirectly reduced when the wet season had consistent rainfall, as such wet seasons allowed fewer wildfires in subsequent fire seasons. Overall area burned at the study site was estimated with high accuracy (R2 score = 0.63). In summary, we found that by using SEMs, we were able to clearly describe causal patterns involving seasonal climate, ENSO and wildfire. We propose that similar approaches could be effectively applied to other sites where seasonality exerts strong and complex forcings on ecological processes.

Slocum, Matthew G.; Orzell, Steve L.

2013-01-01

450

A Structural Equation Model Analysis of Relationships among ENSO, Seasonal Descriptors and Wildfires.  

PubMed

Seasonality drives ecological processes through networks of forcings, and the resultant complexity requires creative approaches for modeling to be successful. Recently ecologists and climatologists have developed sophisticated methods for fully describing seasons. However, to date the relationships among the variables produced by these methods have not been analyzed as networks, but rather with simple univariate statistics. In this manuscript we used structural equation modeling (SEM) to analyze a proposed causal network describing seasonality of rainfall for a site in south-central Florida. We also described how this network was influenced by the El Niño-Southern Oscillation (ENSO), and how the network in turn affected the site's wildfire regime. Our models indicated that wet and dry seasons starting later in the year (or ending earlier) were shorter and had less rainfall. El Niño conditions increased dry season rainfall, and via this effect decreased the consistency of that season's drying trend. El Niño conditions also negatively influenced how consistent the moistening trend was during the wet season, but in this case the effect was direct and did not route through rainfall. In modeling wildfires, our models showed that area burned was indirectly influenced by ENSO via its effect on dry season rainfall. Area burned was also indirectly reduced when the wet season had consistent rainfall, as such wet seasons allowed fewer wildfires in subsequent fire seasons. Overall area burned at the study site was estimated with high accuracy (R (2) score = 0.63). In summary, we found that by using SEMs, we were able to clearly describe causal patterns involving seasonal climate, ENSO and wildfire. We propose that similar approaches could be effectively applied to other sites where seasonality exerts strong and complex forcings on ecological processes. PMID:24086670

Slocum, Matthew G; Orzell, Steve L

2013-09-24

451

Inference of Gene Regulatory Networks with Sparse Structural Equation Models Exploiting Genetic Perturbations  

PubMed Central

Integrating genetic perturbations with gene expression data not only improves accuracy of regulatory network topology inference, but also enables learning of causal regulatory relations between genes. Although a number of methods have been developed to integrate both types of data, the desiderata of efficient and powerful algorithms still remains. In this paper, sparse structural equation models (SEMs) are employed to integrate both gene expression data and cis-expression quantitative trait loci (cis-eQTL), for modeling gene regulatory networks in accordance with biological evidence about genes regulating or being regulated by a small number of genes. A systematic inference method named sparsity-aware maximum likelihood (SML) is developed for SEM estimation. Using simulated directed acyclic or cyclic networks, the SML performance is compared with that of two state-of-the-art algorithms: the adaptive Lasso (AL) based scheme, and the QTL-directed dependency graph (QDG) method. Computer simulations demonstrate that the novel SML algorithm offers significantly better performance than the AL-based and QDG algorithms across all sample sizes from 100 to 1,000, in terms of detection power and false discovery rate, in all the cases tested that include acyclic or cyclic networks of 10, 30 and 300 genes. The SML method is further applied to infer a network of 39 human genes that are related to the immune function and are chosen to have a reliable eQTL per gene. The resulting network consists of 9 genes and 13 edges. Most of the edges represent interactions reasonably expected from experimental evidence, while the remaining may just indicate the emergence of new interactions. The sparse SEM and efficient SML algorithm provide an effective means of exploiting both gene expression and perturbation data to infer gene regulatory networks. An open-source computer program implementing the SML algorithm is freely available upon request.

Cai, Xiaodong; Bazerque, Juan Andres; Giannakis, Georgios B.

2013-01-01

452

Initial evidence for the criterion-related and structural validity of the long versions of the Coach–Athlete Relationship Questionnaire  

Microsoft Academic Search

The aim of the present study was to develop and initially validate a longer version of the direct (Jowett & Ntoumanis, 2004) and meta-perspectives (Jowett, 2009a, 2009b) of the Coach–Athlete Relationship Questionnaire (CART-Q). In Study 1, instruments (e.g. questionnaires, scales, and inventories) that have been used to assess relationship quality in the broader psychological literature were examined and items potentially

Daniel J. A. Rhind; Sophia Jowett

2010-01-01

453

Factor structure of the Child Health Questionnaire Parent Form-50 and predictors of health-related quality of life in children with epilepsy.  

PubMed

PURPOSE: The present study investigated the higher-order summary factor structure of the Child Health Questionnaire Parent Form-50 (CHQ) in a sample of children with new-onset epilepsy. The secondary aim was to identify risk factors predicting health-related quality of life (HRQL) 24 months post-diagnosis. METHODS: Data came from the Health-related Quality of Life in Children with Epilepsy Study (HERQULES, N = 374), a multi-site study documenting HRQL among children with epilepsy from diagnosis through 24 months. Confirmatory factor analysis was used to determine goodness of fit between the original structure of the CHQ and HERQULES data. Multiple regression was used to identify risk factors at diagnosis for HRQL at 24 months. RESULTS: The models demonstrated good fit: baseline: CFI = 0.945; TLI = 0.941; WRMR = 1.461; RMSEA = 0.058; 24 months: CFI = 0.957; TLI = 0.954; WRMR = 1.393; RMSEA = 0.055. Factor loadings were high and no cross-loadings observed (first order: ? = 0.27-0.99, 0.24-0.98; second order: ? = 0.69-0.86, 0.54-0.92; p < 0.001 for all). Controlling for HRQL at diagnosis, predictors for better 24-month HRQL were as follows: physical health: fewer cognitive problems (p = 0.023) and parents with fewer depressive symptoms (p = 0.049); psychosocial health: older parent age (p = 0.043), fewer behavior problems (p = 0.004), and families with better functioning (p = 0.008) and fewer demands (p = 0.009). CONCLUSIONS: The CHQ higher-order summary factor structure was replicated in a sample of children with new-onset epilepsy, and child and family risk factors at diagnosis were found to predict HRQL 24 months post-diagnosis. These findings suggest it is possible to identify at-risk children early in the illness process and provide impetus for adopting family-centered care practices. PMID:23334980

Ferro, Mark A; Landgraf, Jeanne M; Speechley, Kathy N

2013-01-20

454

Transport equations in inhomogeneous semiconductors  

Microsoft Academic Search

A generalized equation for the transport of a physical quantity in inhomogeneous semiconductors is derived from the Boltzmann transport equation. The momentum and energy transport equations, obtained from this equation, extend the previous equations of Blotekjaer and Azoff to inhomogeneous semiconductors with nonparabolic band structure. The momentum transport equation is used tio derive a steady state electric current density equation

R. Kishore

1993-01-01

455

Perfectionism, academic burnout and engagement among Chinese college students: A structural equation modeling analysis  

Microsoft Academic Search

This study aims at identifying the association between perfectionism, academic burnout and engagement in college students. A dual-process model was tested in which negative perfectionism (doubts about actions, concerns over mistakes, et al.) were related to burnout symptoms while positive perfectionism (personal standards and organization) to engagement. A sample of Chinese undergraduates (N=482) completed a battery of questionnaires including the

Yiwen Zhang; Yiqun Gan; Heining Cham

2007-01-01

456

Modified Reynolds' equation and analytical analysis of squeeze-film air damping of perforated structures  

Microsoft Academic Search

We modified the Reynolds equation to extend its applications to squeeze-film air damping of perforated plates (i.e., the hole-plates) by adding a term related to the damping effect of gas flow through holes. The modified Reynolds equation (MRE) is generally effective for a perforated hole-plate with a finite thickness and finite lateral dimensions as well as a non-perforated hole-plate. Analytical

Minhang Bao; Heng Yang; Yuancheng Sun; Paddy J. French

2003-01-01

457

The Neo Personality Inventory-Revised: Factor Structure and Gender Invariance from Exploratory Structural Equation Modeling Analyses in a High-Stakes Setting  

ERIC Educational Resources Information Center

|This study presents new analyses of NEO Personality Inventory-Revised (NEO-PI-R) responses collected from a large British sample in a high-stakes setting. The authors show the appropriateness of the five-factor model underpinning these responses in a variety of new ways. Using the recently developed exploratory structural equation modeling (ESEM)…

Furnham, Adrian; Guenole, Nigel; Levine, Stephen Z.; Chamorro-Premuzic, Tomas

2013-01-01

458

Parental authority questionnaire.  

PubMed

A questionnaire was developed for the purpose of measuring Baumrind's (1971) permissive, authoritarian, and authoritative parental authority prototypes. It consists of 30 items per parent and yields permissive, authoritarian, and authoritative scores for both the mother and the father; each of these scores is derived from the phenomenological appraisals of the parents' authority by their son or daughter. The results of several studies have supported the Parental Authority Questionnaire as a psychometrically sound and valid measure of Baumrind's parental authority prototypes, and they have suggested that this questionnaire has considerable potential as a valuable tool in the investigation of correlates of parental permissiveness, authoritarianism, and authoritativeness. PMID:16370893

Buri, J R

1991-08-01

459

Evaluation of trip-inducing effects of new freeways using a structural equations model system of commuters’ time use and travel  

Microsoft Academic Search

A structural equations model system which represents the effects of transportation control measures on commuters’ daily activity patterns after work hours is presented. A commuter’s daily activity after work till going to sleep is defined in terms of variables that indicate time use and travel. These variables are the endogenous variables of the structural equations model system. The parameters of

Satoshi Fujii; Ryuichi Kitamura

2000-01-01

460

Phraselator Questionnaire Responses.  

National Technical Information Service (NTIS)

A questionnaire designed to elicit Soldier judgments of, and comments about, the upgraded Phraselator speech translation device was completed by seven personnel serving in Iraq. Aggregate responses to yes or no questions are provided, as are the frequency...

J. D. Walrath

2009-01-01

461

Designing Establishment Survey Questionnaires.  

National Technical Information Service (NTIS)

In this paper, we demonstrate how establishment survey questionnaire design can be improved by utilizing different research methods such as focus groups, document design analyses, pretests, and response analysis surveys. We discuss the lack of research on...

K. L. Goldenberg P. A. Phipps S. Butani

2008-01-01

462

The functional status questionnaire  

Microsoft Academic Search

A comprehensive functional assessment requires thorough and careful inquiry, which is difficult to accomplish in most busy\\u000a clinical practices. This paper examines the reliability and validity of the Functional Status Questionnaire (FSQ), a brief,\\u000a standardized, self-administered questionnaire designed to provide a comprehensive and feasible assessment of physical, psychological,\\u000a social and role function in ambulatory patients. The FSQ can be completed

Alan M. Jette; Allyson R. Davies; Paul D. Cleary; David R. Calkins; Lisa V. Rubenstein; Arlene Fink; Jacqueline Kosecoff; Roy T. Young; Robert H. Brook; Thomas L. Delbanco

1986-01-01

463

The Shorter PROMIS Questionnaire  

Microsoft Academic Search

There is both a theoretical and clinical need to develop a questionnaire that assesses a range of addictive behaviours. The Shorter PROMIS Questionnaire (SPQ) is a 16-scale self-report instrument assessing the use of nicotine, recreational drugs, prescription drugs, gambling, sex, caffeine, food bingeing, food starving, exercise, shopping, work, relationships dominant and submissive, and compulsive helping dominant and submissive. Clinical cut-off

George Christo; Susan L Jones; Samantha Haylett; Geoffrey M Stephenson; Robert M. H Lefever; Robin Lefever

2003-01-01

464

Basics of Developing Questionnaires  

NSDL National Science Digital Library

Whether developing questions for questionnaires or interviews or focus groups, there are certain guidelines that help to ensure that respondents provide information that is useful and can later be analyzed. This resource offers advice on developing questions for interviews or focus groups. It contains basics conducting the interviews, providing directions to respondents as well as guidelines for composing the content and wording of the questionnaire. This resource is aimed for use in workshops/conferences and is intended for novice evaluators.

Mcnamara, Carter

465

Integral equation analysis of complex (M)MIC-structures with optimized system matrix decomposition and novel quadrature techniques  

NASA Astrophysics Data System (ADS)

Using integral equation methods for the analysis of complex (M)MIC structures, the computation and storage effort for the solution of the linear systems of equations with their fully populated matrices still forms the main bottleneck. In the last years, remarkable improvements could be achieved by means of diakoptic methods and related preconditiners. In this contribution, we present a method based on the optimized decomposition of the system matrix depending on the circuit topology. The system matrix is splitted in a densely populated matrix and a mainly blockdiagonal matrix with overlapping submatrices. The latter matrix is used for the generation of high performance preconditioners within Krylov subspace methods using sparsified matrix storage methods, adaptive Cholesky decompositions and optimized forward/backward substitutions. Furthermore, we present an integration technique using a complete analytical treatment for the strongly oscillating parts of the spectral domain integrands allowing the analysis of very large structures as compared to the wavelength.

Vaupel, T.; Hansen, V.

2004-05-01

466

Complex interactions among biocontrol agents, pollinators, and an invasive weed: a structural equation modeling approach.  

PubMed

Herbivores, seed predators, and pollinators can exert strong impacts on their host plants. They can also affect the strength of each other's impact by modifying traits in their shared host, producing super- or sub-additive outcomes. This phenomenon is especially relevant to biological control of invasive plants because most invaders are attacked by multiple agents. Unfortunately, complex interactions among agents are rarely studied. We used structural equation modeling (SEM) to quantify the effect of two biocontrol agents and generalist pollinators on the invasive weed Centaurea solstitialis, and to identify and quantify the direct and indirect interaction pathways among them. The weevil Eustenopus villosus is both a bud herbivore and a predispersal seed predator; the fly Chaetorellia succinea is also a predispersal seed predator; Apis mellifera is the primary pollinator. We conducted this work at three sites spanning the longitudinal range of C. solstitialis in California (USA) from the coast to the Sierra Nevada Mountains. SEM revealed that bud herbivory had the largest total effect on the weed's fecundity. The direct effect of bud herbivory on final seed set was 2-4 times larger in magnitude than the direct effect of seed predation by both agents combined. SEM also revealed important indirect interactions; by reducing the number of inflorescences plants produced, bud herbivory indirectly reduced the plant's attractiveness to ovipositing seed predators. This indirect, positive pathway reduced bud herbivory's direct negative effect by 11-25%. In the same way, bud herbivory also reduced pollinator visitation, although the magnitude of this pathway was relatively small. E. villosus oviposition deterred C. succinea oviposition, which is unfortunate because C. succinea is the more voracious of the seed predators. Finally, C. succinea oviposition indirectly deterred pollinator visitation, thereby enhancing its net effect on the plant. This study demonstrates the powerful insights that can be gained from the SEM approach in understanding the multiple direct and indirect interactions among agents and pollinators and their effects on an invasive weed. Such an approach may improve our ability to manage weeds with biocontrol agents by identifying pathways that could be exploited by future agents and minimizing the possibility of interference with established agents. PMID:23387114

Swope, Sarah M; Parker, Ingrid M

2012-12-01

467

Cognitive Social Maturity, Life Change Events, and Health Risk Behaviors among Adolescents: Development of a Structural Equation Model  

Microsoft Academic Search

\\u000aPurpose: To examine the roles of cognitive social maturity and life change events in a structural equation model (SEM) to explain adolescents' use of marijuana, tobacco, and alcohol. Methods: Data were derived from 1322 9th and 10th graders in a HIV prevention study. Students completed a survey of their cognitive social maturity, recent life events and substance use habits. A

Carolyn E. Ievers-Landis; Rachel Neff Greenley; Chris Burant; Elaine Borawski

2006-01-01

468

“I Feel Present. Therefore, I Experience Flow:” A Structural Equation Modeling Approach to Flow and Presence in Video Games  

Microsoft Academic Search

Driven by theories of flow and presence, three studies examined the antecedents and consequences of flow across three different video game genres. Structural equation modeling analyses reveal the roles of (1) physical presence in medical simulation games; (2) spatial presence in driving games; and (3) self-presence in avatar-based narrative-driven games. A 3 (skill: low, medium, high) × 3 (challenge: low,

Seung-A Annie Jin

2011-01-01

469

Individual, social environmental, and physical environmental influences on physical activity among black and white Adults: A Structural Equation Analysis  

Microsoft Academic Search

Background: Social ecological models suggest that conditions in the social and physical environment, in addition to individual factors,\\u000a play important roles in health behavior change. Using structural equation modeling, this study tested a theoretically and\\u000a empirically based explanatory model of physical activity to examine theorized direct and indirect effects of individual (e.g.,\\u000a motivation and self-efficacy), social environmental (e.g., social support),

Lorna Haughton McNeill; Kathleen W. Wyrwich; Ross C. Brownson; Eddie M. Clark; Matthew W. Kreuter

2006-01-01

470

Using structural equation modeling and expert elicitation to select nutrient criteria variables for south-central Florida lakes  

Microsoft Academic Search

Kenney, M.A., G.B. Arhonditsis, L.C. Reiter, M. Barkley, and K.H. Reckhow. 2009. Using structural equation modeling and expert elicitation to select nutrient criteria variables for south-central Florida lakes.To protect the nation's waterbodies from excessive impairments from pollution leading to eutrophication, the Clean Water Act requires states to establish water quality standards. These water quality standards are designed to protect the

Melissa A. Kenney; George B. Arhonditsis; Linda C. Reiter; Matthew Barkley; Kenneth H. Reckhow

2009-01-01

471

Exploration of lagged relationships between mastitis and milk yield in dairycows using a Bayesian structural equation Gaussian-threshold model  

Microsoft Academic Search

A Gaussian-threshold model is described under the general framework of structural equation models for inferring simultaneous and recursive relationships between binary and Gaussian characters, and estimating genetic parameters. Relationships between clinical mastitis (CM) and test-day milk yield (MY) in first-lactation Norwegian Red cows were examined using a recursive Gaussian-threshold model. For comparison, the data were also analyzed using a standard

Xiao-Lin Wu; Bjørg Heringstad; Daniel Gianola

2008-01-01

472

A Model for Integrating Fixed, Random, and Mixed-Effects Meta-Analyses Into Structural Equation Modeling  

Microsoft Academic Search

Meta-analysis and structural equation modeling (SEM) are two important statistical methods in the behavioral, social, and medical sciences. They are generally treated as two unrelated topics in the literature. The present article proposes a model to integrate fixed-, random-, and mixed-effects meta-analyses into the SEM framework. By applying an appropriate transformation on the data, studies in a meta-analysis can be

Mike W.-L. Cheung

2008-01-01

473

Impacts of Information and Communication Technologies (ICT) on time use and travel behavior: a structural equations analysis  

Microsoft Academic Search

The objective of this paper is to contribute an empirical study to the literature on transportation impacts of Information\\u000a and Communications Technologies (ICT). The structural equation model (SEM) is employed to analyze the impacts of ICT usage\\u000a on time use and travel behavior. The sample is derived from the travel characteristic survey conducted in Hong Kong in 2002.\\u000a The usage

Donggen Wang; Fion Yuk Ting Law

2007-01-01

474

The higher grading structure of the WKI hierarchy and the two-component short pulse equation  

NASA Astrophysics Data System (ADS)

A higher grading affine algebraic construction of integrable hierarchies, containing the Wadati-Konno-Ichikawa (WKI) hierarchy as a particular case, is proposed. We show that a two-component generalization of the Schäfer-Wayne short pulse equation arises quite naturally from the first negative flow of the WKI hierarchy. Some novel integrable nonautonomous models are also proposed. The conserved charges, both local and nonlocal, are obtained from the Riccati form of the spectral problem. The loop-soliton solutions of the WKI hierarchy are systematically constructed through gauge followed by reciprocal Bäcklund transformation, establishing the precise connection between the whole WKI and AKNS hierarchies. The connection between the short pulse equation with the sine-Gordon model is extended to a correspondence between the two-component short pulse equation and the Lund-Regge model.

França, G. S.; Gomes, J. F.; Zimerman, A. H.

2012-08-01

475

The Kuramoto-Sivashinsky equation for adatoms interacting through quasi-Rayleigh waves and formation of ordered adatom structures  

NASA Astrophysics Data System (ADS)

It is shown that the defect-deformational (DD) cooperative nucleation of ordered ensembles of nanoparticles on isotropic surfaces of solids with the participation of quasi-Rayleigh waves can be described by a closed two-dimensional nonlinear DD equation of the Kuramoto-Sivashinsry (KS) type. A solution to the linearized DDKS equation describes the threshold appearance of the periodic surface strain modulation accompanied by the simultaneous formation of adatom (surface defect) piles at extrema of the surface strain. Numerical solutions to the DDKS equation in linear and nonlinear regimes describe the formation of three types of surface structures of adatom piles (clusters): lamellar-like structures, cellular disordered and hexagonal ordered ones. In the well-developed nonlinear regime, generated ensembles of nanoparticles become trimodal regarding their size distribution due to the generation of the second harmonics, degenerate parametric decay and summation of wavevectors of DD gratings taking part in the DD selforganization. The selforganizing periodic cellular DD surface structure can serve as a selforganized template for the subsequent growth of nanoparticles in the processes of atoms deposition.

Emel'yanov, Vladimir I.; Kuratov, Andrey S.

2013-09-01

476

The global finite structure of generic envelope loci for Hamilton-Jacobi equations  

NASA Astrophysics Data System (ADS)

We discuss in some detail the existence of global generating functions describing Lagrangian submanifolds connected with evolution problems for Hamilton-Jacobi (H-J) equations. First, we produce a physical application of a result by Viterbo: for generic (in a suitable sense) Hamiltonian functions and initial data, the envelopes, i.e., the wave front sets, related to Hamilton-Jacobi problems are globally finitely generated. Furthermore, we show how to compute global space-time generating functions with finite parameters for geometric solutions of a H-J equation of the evolution kind.

Cardin, Franco

2002-01-01

477

Electronic structure and equation of state data of warm dense gold  

SciTech Connect

Equation of state data and electrical resistivity of warm dense gold were measured in the internal energy range 8-12 MJ/kg. Experimental results were compared with quantum molecular dynamics simulations. The theoretical results match well the experimental data, allowing a detailed interpretation of the theoretical thermodynamic properties and frequency-dependent conductivities.

Renaudin, P.; Recoules, V.; Noiret, P.; Clerouin, J. [Departement de Physique Theorique et Appliquee, CEA/DAM Ile-de-France, BP12, 91680 Bruyeres-le-Chatel Cedex (France)

2006-05-15

478

Multivariate Methods for the Comparison of Factor Structures in Cross-Cultural ResearchAn Illustration with the Big Five Questionnaire  

Microsoft Academic Search

The goal of the present study was to demonstrate the value of a multiple data analytic approach for testing the cross-cultural generalizability of a personality measure. Data were collected in four different countries (Italy, Germany, Spain, and the United States) on the Big Five Questionnaire (BFQ), which is a measure of the Five Factor Model of personality traits. Different analytical

Gian Vittorio Caprara; Claudio Barbaranelli; José Bermúdez; Christina Maslach; Willibald Ruch

2000-01-01

479

The Questionnaire of Lifestyle Change in Regard to Problematic Internet Use: Factor Structure and Concurrent and Cross-Year Predictive Utilities  

ERIC Educational Resources Information Center

This study constructed a questionnaire, named "Lifestyle Change in Regard to Problematic Internet Use (LC-PIU)," for helping school psychologists detect early indications of PIU-related lifestyle changes in university populations. Our focus is on all university students who use the Internet, not users who already show dependent symptoms. The…

Yeh, Yu-Chen; Lin, Sunny S. J.; Tseng, Yin-Hsing; Hwang, Fang-Ming

2012-01-01

480

A structural equation model relating impaired sensorimotor function, fear of falling and gait patterns in older people.  

PubMed

Many falls in older people occur while walking, however the mechanisms responsible for gait instability are poorly understood. Therefore, the aim of this study was to develop a plausible model describing the relationships between impaired sensorimotor function, fear of falling and gait patterns in older people. Temporo-spatial gait parameters and acceleration patterns of the head and pelvis were obtained from 100 community-dwelling older people aged between 75 and 93 years while walking on an irregular walkway. A theoretical model was developed to explain the relationships between these variables, assuming that head stability is a primary output of the postural control system when walking. This model was then tested using structural equation modeling, a statistical technique which enables the testing of a set of regression equations simultaneously. The structural equation model indicated that: (i) reduced step length has a significant direct and indirect association with reduced head stability; (ii) impaired sensorimotor function is significantly associated with reduced head stability, but this effect is largely indirect, mediated by reduced step length, and; (iii) fear of falling is significantly associated with reduced step length, but has little direct influence on head stability. These findings provide useful insights into the possible mechanisms underlying gait characteristics and risk of falling in older people. Particularly important is the indication that fear-related step length shortening may be maladaptive. PMID:16697643

Menz, Hylton B; Lord, Stephen R; Fitzpatrick, Richard C

2006-05-12

481

Multiterm solution of a generalized Boltzmann kinetic equation for electron and positron transport in structured and soft condensed matter.  

PubMed

In this paper, we generalize the semiclassical Boltzmann kinetic equation for dilute gases to consider highly nonequilibrium electrons and positrons in soft condensed matter, accounting rigorously for all types of interactions, including positronium formation, and allowing for both coherent and incoherent scattering processes. The limitations inherent in the seminal paper of Cohen and Lekner [M. H. Cohen and J. Lekner, Phys. Rev. 158, 305 (1967); Y. Sakai, J. Phys. D 40, R441 (2007)] are avoided by solving the kinetic equation using a "multiterm" spherical harmonic representation of the velocity distribution function, as well as formulating a necessarily nonperturbative treatment of nonconservative collisional processes such as positronium formation. Numerical calculations of transport properties are carried out for a Percus-Yevick model of a hard-sphere system, and for positrons in liquid argon. New phenomena are predicted, including structure-induced negative conductivity and anisotropic diffusion. PMID:22060346

White, R D; Robson, R E

2011-09-23

482

CONDENSED MATTER: STRUCTURE, MECHANICAL AND THERMAL PROPERTIES: Modified Transition Temperature Equation for Superconductors  

Microsoft Academic Search

We present the replacement and modification of the Debye temperature thetaD by the average phonon frequency in the Rowell (Solid State Commun. 19 (1976) 1131) linear transition-temperature equation for superconducting materials. We not only improve Rowell's results but also describe the experimental results accurately and consistently for the various superconducting systems which cover the entire range of lambda between 0.72

Vora M. Aditya

2008-01-01

483

Elaborated constitutive equations for structural analysis for creep, swelling, and damage under irradiation  

Microsoft Academic Search

This paper reports on the constitutive equations for creep, swelling, and damage under irradiation discussed in terms of incorporating the transient behavior of swelling after the incubation fluence as well as the effect of transient creep. Creep during irradiation is assumed to consist of irradiation-induced creep and irradiation-affected thermal creep, and the dilatational part of irradiation-induced creep is identified with

S. Murakami; M. Mizuno

1991-01-01

484

Noise-sustained structure, intermittency, and the Ginzburg-Landau equation  

SciTech Connect

The time-dependent generalized Ginzburg-Landau equation is a partial differential equation that is related to many physical systems. In the stationary (i.e., laboratory) frame of reference the equation is: Partial psi/partial t = a psi - ..nu.. (partial psi/partial x) + b (partial squared x/partial x/sup 2/) - c (psi absolute)/sup 2/ psi where the dependent variable psi is in general complex; a, b, and c are constants which are in general complex; and ..nu.. is the group velocity. Consider a small initial localized perturbation about the equilibrium state psi=O. A linear stability analysis reveals that there are three types of behavior which this perturbation can undergo. (1) The perturbation will be damped in any frame of reference. This behavior corresponds to the system being absolutely stable. (2) The perturbation will grow and spread such that the edges of the pertubation move in opposite directions. This behavior corresponds to the system being absolutely unstable. The perturbation will be damped at any given stationary point but a frame of reference may be found in which the perturbation is growing. In other words, even though the perturbation is growing and spreading, it is moving at a sufficiently large velocity such that both edges of the perturbation are moving in the same direction. Thus the system behind the perturbation returns to its undisturbaed state. This behavior corresponds to the system being spatially unstable (i.e., convectively unstable).

Deissler, R.J.

1985-01-01

485

Replication and Validation of the Drinking Motive Questionnaire Revised (DMQ-R, Cooper, 1994) among Adolescents in Switzerland  

Microsoft Academic Search

This paper has two aims: (1) to replicate the four-dimensional structure of the Drinking Motive Questionnaire Revised (DMQ-R) in a national representative sample from Switzerland, and (2) to validate the relevance of distinguishing drinking motives by inspecting the relations with expected consequences, alcohol use, and alcohol-related and other problems. Confirmatory factor analysis and linear structural equation models were estimated based

Emmanuel Kuntsche; Ronald Knibbe; Gerhard Gmel; Rutger Engels

2006-01-01

486

Integration of Poisson Equation for the Diamond-Structure Semiconductors by the Green Function Cellular Method (GFCM)  

NASA Astrophysics Data System (ADS)

Solving the Poisson equation for the electrostatic potential in a solid is an integral part of a modern electronic structure calculation. In this work, the Poisson equation for the diamond-structure semiconductors is solved using the Green Function Cellular Method. The charge density was obtained from a first principle consideration of the atomic wave functions for the electrons. The real solid harmonics JL, and HL are used in expanding the Poisson equation Green function, therefore, most of the calculations were done in the spherical coordinates system. The maximum value of the index L considered is six. The Poisson equation is solved only for the state k = 0 in this work. The results show that the total electron-electron Coulomb potential, VCE(rn) is given mainly by the central cell contribution and thus varies in a similar fashion. From a certain value at the origin, the total potential initially increases with the distance up to a certain point and then decreases as the distance is further advanced. The peak potential is roughly at about 0.05d in carbon, 0.03d in silicon and germanium, and 0.02d in gray tin. The rate of convergence of the external cells potential contribution over the l summation is faster than the central cell contribution, while the total potential rate is the slowest. In general the rate of convergence at a given point depends on the distance and direction of the point. The mathematical formulation and the results of the calculations are presented and discussed

Babaji, G.; Hussain, L. A.

487

Questionnaire typography and production.  

PubMed

This article describes the typographic principles and practice which provide the basis of good design and print, the relevant printing processes which can be used, and the graphic designer's function in questionnaire production. As they impose constraints on design decisions to be discussed later in the text, the various methods of printing and production are discussed first. PMID:15677172

Gray, M