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1

A Model and Questionnaire of Language Identity in Iran: A Structural Equation Modelling Approach  

ERIC Educational Resources Information Center

This study consisted of three main phases including the development of a hypothesised model of language identity in Iran, developing and validating a questionnaire based on this model and finally testing the model based on the questionnaire data. In the first phase of this research, a hypothesised model of language identity in Iran was developed…

Khatib, Mohammad; Rezaei, Saeed

2013-01-01

2

Testing measurement invariance across Spanish and English versions of the physical self-description questionnaire: an application of exploratory structural equation modeling.  

PubMed

Test of measurement invariance across translated versions of questionnaires is a critical prerequisite to comparing scores on the different versions. In this study, we used exploratory structural equation modeling (ESEM) as an alternative approach to evaluate the measurement invariance of the Spanish version of the Physical Self-Description Questionnaire (PSDQ). The two versions were administered to large samples of Australian and Spanish adolescents. First, we compared the CFA and ESEM approaches and showed that ESEM fitted the data much better and resulted in substantially more differentiated factors. We then tested measurement invariance with a 13-model ESEM taxonomy. Results justified using the Spanish version of the PSDQ to carry out cross-cultural comparisons in sport and exercise psychology research. Overall, the study can stimulate research on physical self-concept across countries and foster better cross-cultural comparisons. PMID:24686954

Tomás, Inés; Marsh, Herbert W; González-Romá, Vicente; Valls, Víctor; Nagengast, Benjamin

2014-04-01

3

Paper to Electronic Questionnaires: Effects on Structured Questionnaire Forms  

NASA Technical Reports Server (NTRS)

With the use of computers, paper questionnaires are being replaced by electronic questionnaires. The formats of traditional paper questionnaires have been found to effect a subject's rating. Consequently, the transition from paper to electronic format can subtly change results. The research presented begins to determine how electronic questionnaire formats change subjective ratings. For formats where subjects used a flow chart to arrive at their rating, starting at the worst and middle ratings of the flow charts were the most accurate but subjects took slightly more time to arrive at their answers. Except for the electronic paper format, starting at the worst rating was the most preferred. The paper and electronic paper versions had the worst accuracy. Therefore, for flowchart type of questionnaires, flowcharts should start at the worst rating and work their way up to better ratings.

Trujillo, Anna C.

2009-01-01

4

Measurement invariance of the Childhood Trauma Questionnaire across gender and race\\/ethnicity: Applications of structural equation modeling and item response theory  

Microsoft Academic Search

Research has established associations between child maltreatment and a wide range of deleterious psychological sequelae for both women and men across racial\\/ethnic groups. This research, however, tends to be marked by methodological pitfalls, one of which has been the use of non-standardized retrospective measurement instruments that have not been subjected to rigorous validation procedures. The Childhood Trauma Questionnaire (CTQ-SF; Bernstein

Brett D Thombs

2004-01-01

5

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

6

Component Structure of the Attribution Style Questionnaire.  

ERIC Educational Resources Information Center

The Attribution Style Questionnaire (ASQ) is a short (36-item) objective inventory which assesses cognitions regarding responsibility for bad and good outcomes relevant to cognitive models of depression. Three alternative scoring systems have been proposed; no scoring system has been empirically verified. Convergent and discriminant validity have…

Huckel, Lorraine H.; Velicer, Wayne F.

7

Equational Sentence Structure in Eskimo.  

ERIC Educational Resources Information Center

A comparison of the syntactic characteristics of mathematical equations and Eskimo syntax is made, and a proposal that Eskimo has a level of structure similar to that of equations is described. P:t performative contrast is reanalyzed. Questions and speculations on the formal treatment of this type of structure in transformational grammar, and its…

Hofmann, Th. R.

8

A Structural Examination of the Learning Experiences Questionnaire  

ERIC Educational Resources Information Center

The underlying factor structure of the Learning Experiences Questionnaire (LEQ; Schaub, 2004) was examined using data from 742 male and female college-age respondents. The LEQ items reflect a variety of learning experiences (generated based on Bandura's (1986, 1997) four sources of self-efficacy perceptions) that might occur in each of Holland's…

Tokar, David M.; Buchanan, Taneisha S.; Subich, Linda M.; Hall, Rosalie J.; Williams, Christine M.

2012-01-01

9

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

10

Structural and Convergent Validity of the Homework Performance Questionnaire  

ERIC Educational Resources Information Center

Homework is a requirement for most school-age children, but research on the benefits and drawbacks of homework is limited by lack of psychometrically sound measurement of homework performance. This study examined the structural and convergent validity of scores from the newly developed Homework Performance Questionnaire -- Teacher Scale (HPQ-T).…

Pendergast, Laura L.; Watkins, Marley W.; Canivez, Gary L.

2014-01-01

11

The factorial structure of the Chronic Liver Disease Questionnaire (CLDQ)  

Microsoft Academic Search

Objective  The Chronic Liver Disease Questionnaire (CLDQ) is a disease-specific instrument designed to assess health-related quality\\u000a of life in patients with chronic liver disease. The aim of this paper is to present the psychometric properties of a German\\u000a version of this questionnaire. A special focus is placed on the analysis of the CLDQ’s factorial structure.\\u000a \\u000a \\u000a \\u000a Methods  Five hundred and twenty-four patients completed

Karl-Heinz Schulz; Sylvia Kroencke; Heike Ewers; Holger Schulz; Zobair M. Younossi

2008-01-01

12

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. PMID:18698268

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

2010-01-01

13

The Specific Analysis of Structural Equation Models  

ERIC Educational Resources Information Center

Conventional structural equation modeling fits a covariance structure implied by the equations of the model. This treatment of the model often gives misleading results because overall goodness of fit tests do not focus on the specific constraints implied by the model. An alternative treatment arising from Pearl's directed acyclic graph theory…

McDonald, Roderick P.

2004-01-01

14

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

15

A Three-Stage Estimation Procedure for Structural Equation Models with Polytomous Variables.  

ERIC Educational Resources Information Center

A computationally efficient three-stage estimator of thresholds and covariance structure parameters is prepared for analysis of structural equation models with polytomous variables. The method is based on partition maximum likelihood and generalized least squares estimation. An analysis of questionnaire responses of 739 young adults illustrates…

Lee, Sik-Yum; And Others

1990-01-01

16

Confirmation Bias in Structural Equation Modeling.  

ERIC Educational Resources Information Center

A theoretical and philosophical revision of the concept of fit in structural equation modeling and its relation to a confirmation bias is developed. The neutral character of fit indexes regarding this issue is argued, concluding that protection against confirmation bias relies on model modification strategy and scientist behavior. (SLD)

Robles, Jaime

1996-01-01

17

Quantifying parsimony in structural equation modeling  

E-print Network

Fitting propensity (FP) is defined as a model's average ability to fit diverse data patterns, all else being equal. The relevance of FP to model selection is examined in the context of structural equation modeling (SEM). In SEM it is well known...

Preacher, K. J.

2006-01-01

18

Structural Equation Modeling in Rehabilitation Counseling Research  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) has become increasingly popular in counseling, psychology, and rehabilitation research. The purpose of this article is to provide an overview of the basic concepts and applications of SEM in rehabilitation counseling research using the AMOS statistical software program.

Chan, Fong; Lee, Gloria K.; Lee, Eun-Jeong; Kubota, Coleen; Allen, Chase A.

2007-01-01

19

Errors of Inference in Structural Equation Modeling  

ERIC Educational Resources Information Center

Although structural equation modeling (SEM) is one of the most comprehensive and flexible approaches to data analysis currently available, it is nonetheless prone to researcher misuse and misconceptions. This article offers a brief overview of the unique capabilities of SEM and discusses common sources of user error in drawing conclusions from…

McCoach, D. Betsy; Black, Anne C.; O'Connell, Ann A.

2007-01-01

20

A Brief Guide to Structural Equation Modeling  

ERIC Educational Resources Information Center

To complement recent articles in this journal on structural equation modeling (SEM) practice and principles by Martens and by Quintana and Maxwell, respectively, the authors offer a consumer's guide to SEM. Using an example derived from theory and research on vocational psychology, the authors outline six steps in SEM: model specification,…

Weston, Rebecca; Gore, Paul A., Jr.

2006-01-01

21

Sensitivity Analysis of Structural Equation Models.  

ERIC Educational Resources Information Center

The sensitivity analysis of structural equation models when minor perturbation is introduced is investigated. An influence measure based on the general case weight perturbation is derived for the generalized least squares estimation, and an influence measure is developed for the special case deletion perturbation scheme. (Author/SLD)

Lee, Sik-Yum; Wang, S. J.

1996-01-01

22

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

23

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

24

On the evaluation of structural equation models  

Microsoft Academic Search

Criteria for evaluating structural equation models with latent variables are defined, critiqued, and illustrated. An overall\\u000a program for model evaluation is proposed based upon an interpretation of converging and diverging evidence. Model assessment\\u000a is considered to be a complex process mixing statistical criteria with philosophical, historical, and theoretical elements.\\u000a Inevitably the process entails some attempt at a reconcilation between so-called

Richard P. Bagozzi; Youjae Yi

1988-01-01

25

Social Exchange, Equity, and Commitment: Structural Equation Modeling of Dating Relationships  

Microsoft Academic Search

Structural equation modeling was used in 2 studies to evaluate the social exchange hypothesis, which states that relationship commitment results from satisfaction with the relationship, paired with the limited availability of desirable alternative relationships. College students in intimate relationships completed questionnaire measures of commitment, satisfaction, perceptions of alternatives, and inequity. The initial study (N = 238) supported the social exchange

Frank J. Floyd; Guenter H. Wasner

1994-01-01

26

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

Microsoft Academic Search

This study investigated cross-cultural differences in the factor structure and psychometric properties of the Young Schema\\u000a Questionnaire (short form; YSQ-SF). The participants were 712 Chinese undergraduate students. The total sample was randomly\\u000a divided into two sub-samples. Exploratory Factor Analysis (EFA) was conducted on questionnaire results for Group A, and Confirmatory\\u000a Factor Analysis (CFA) was conducted on Group B. Multiple regression

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

27

Sexual Offenders' Modus Operandi: A Comparison of Structured Interview and Questionnaire Approaches.  

ERIC Educational Resources Information Center

Clinical practice has supported the use of structured interviews with perpetrators and victims of sexual offenses. However, empirical studies have not examined the differential utility of structured interviews and self-report questionnaires for obtaining information about sex offenders' modus operandi. Compares the ability of these two assessment…

Kaufman, Keith L.; And Others

1996-01-01

28

Sexual Offenders' Modus OperandiA Comparison of Structured Interview and Questionnaire Approaches  

Microsoft Academic Search

Clinical practice has long supported the use of structured interviews with both perpetrators and victims of sexual offenses. However, empirical studies have not examined the differential utility of structured interviews and self-report questionnaires for obtaining information about sex offenders' modus operandi. This investigation compared the ability of these two assessment approaches to provide details regarding sexual offenders' modus operandi from

KEITH L. KAUFMAN; DANIEL R. HILLIKER; PATTY LATHROP; ERIC L. DALEIDEN; LESLIE RUDY

1996-01-01

29

The Abridged Dutch Metamemory in Adulthood (MIA) Questionnaire: Structure and Effects of Age, Sex, and Education  

Microsoft Academic Search

This study presents data on the factor structure, reliability, and discriminant validity of the Metamemory in Adulthood (MIA) questionnaire in a Dutch sample of 1, 899 normal and healthy participants aged 24 to 86 years. The factor structure of the Dutch MIA corresponded with that of the original MIA. The Strategy scale could be divided into two subscales: External and

Rudolf W. H. M. Ponds; Jellemer Jolles

1996-01-01

30

An Atmospheric Structure Equation for Grain Growth  

E-print Network

We present a method to include the evolution of the grain size and grain opacity $\\kappa_\\mathrm{gr}$ in the equations describing the structure of protoplanetary atmospheres. The key assumption of this method is that a single grain size dominates the grain size distribution at any height $r$. In addition to following grain growth, the method accounts for mass deposition by planetesimals and grain porosity. We illustrate this method by computation of a simplified atmosphere structure model. In agreement with previous works, grain coagulation is seen to be very efficient. The opacity drops to values much below the often-used `ISM-opacities' ($\\sim$$1\\ \\mathrm{cm^2\\ g}^{-1}$) and the atmosphere structure profiles for temperature and density resemble that of the grain-free case. Deposition of planetesimals in the radiative part of the atmosphere hardly influences this outcome as the added surface is quickly coagulated away. We observe a modest dependence on the internal structure (porosity), but show that filling...

Ormel, Chris W

2014-01-01

31

Temperament factor structure in fragile X syndrome: the children's behavior questionnaire.  

PubMed

Early patterns of temperament lay the foundation for a variety of developmental constructs such as self-regulation, psychopathology, and resilience. Children with fragile X syndrome (FXS) display unique patterns of temperament compared to age-matched clinical and non-clinical samples, and early patterns of temperament have been associated with later anxiety in this population. Despite these unique patterns in FXS and recent reports of atypical factor structure of temperament questionnaires in Williams Syndrome (Leyfer, John, Woodruff-Borden, & Mervis, 2012), no studies have examined the latent factor structure of temperament scales in FXS to ensure measurement validity in this sample. The present study used confirmatory factor analysis to examine the factor structure of a well-validated parent-reported temperament questionnaire, the Children's Behavior Questionnaire (Rothbart, Ahadi, Hershey, & Fisher, 2001), in a sample of 90 males with FXS ages 3-9 years. Our data produced a similar, but not identical, three-factor model that retained the original CBQ factors of negative affectivity, effortful control, and extraversion/surgency. In particular, our FXS sample demonstrated stronger factor loadings for fear and shyness than previously reported loadings in non-clinical samples, consistent with reports of poor social approach and elevated anxiety in this population. Although the original factor structure of the Children's Behavior Questionnaire is largely retained in children with FXS, differences in factor loading magnitudes may reflect phenotypic characteristics of the syndrome. These findings may inform future developmental and translational research efforts. PMID:24380785

Roberts, Jane E; Tonnsen, Bridgette L; Robinson, Marissa; McQuillin, Samuel D; Hatton, Deborah D

2014-02-01

32

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

33

Examining adversarial growth in illness: The factor structure of the silver lining questionnaire (SLQ-38)  

Microsoft Academic Search

The Silver Lining Questionnaire (SLQ-38) is purported to measure 10 aspects of adversarial growth in illness. To date however, no empirical evidence exists to support this claim. Hence the aim of this study was to investigate the factor structure of the SLQ-38 in a sample of 560 individuals with multiple sclerosis (MS), cancer, cardiac, and renal disease. The results demonstrate

Orla MC Bride; Lynn Dunwoody; Andrea Lowe-Strong; Susan M. Kennedy

2008-01-01

34

An examination of the factor structure of the Sociocultural Attitudes Towards Appearance Questionnaire3 in Malaysia  

Microsoft Academic Search

The present study examined the factor structure of a Malay translation of the Sociocultural Attitudes Towards Appearance Questionnaire-3 among a community sample of 554 Malaysian women. Results of an exploratory factor analysis revealed the existence of four factors, two of which (Information and Internalization-Athlete) mirrored those found among Western samples. An additional factor was an amalgamation of two factors reported

Viren Swami

2009-01-01

35

Integrable Systems of Partial Differential Equations Determined by Structure Equations and Lax pair  

E-print Network

It is shown how a system of evolution equations can be developed both from the structure equations of a submanifold embedded in three-space as well as from a matrix SO(6) Lax pair. The two systems obtained this way correspond exactly when a constraint equation is selected and imposed on the system of equations. This allows the coefficients of the second fundamental form to be selected in a more general way so they need not be constants.

Paul Bracken

2009-07-02

36

Psychometric properties and factor structure of an L2 reading motivation questionnaire.  

PubMed

The purpose of this study is to investigate the psychometric properties and factor structure of a popular second language reading motivation questionnaire developed by Mori (2002). 550 first year high school students in Korea answered the 30-item questionnaire which consists of statements indicating different degrees of English reading motivation. Exploratory factor analysis was conducted with principal axis factoring and promax rotation, which yielded a four-factor solution. The factors included 'Intercultural and Intellectual Orientation', 'Reading Efficacy', 'Intrinsic Motivation', and 'Negative Attitudes'. The results supported the multidimensionality of the construct of L2 reading motivation, but could not replicate the nine factor structure which was originally proposed by Mori. The implications for further research on L2 reading motivation and development of a more valid L2 reading scale are discussed. PMID:24704649

Kim, Hee-jung; Choi, Sunhee

2014-01-01

37

Three-Dimensional Structured Networks for Matrix Equation Solving  

Microsoft Academic Search

Two three-dimensional structured networks are developed for solving linear equations and the Lyapunov equation. The basic idea of the structured network approaches is to first represent a given equation-solving problem by a 3-D structured network so that if the network matches a desired pattern array, the weights of the linear neurons give the solution to the problem: then, train the

Li-xin Wang; Jerry M. Mendel

1991-01-01

38

Analysis of consumers' preferences and behavior with regard to horse meat using a structured survey questionnaire.  

PubMed

In this study, a structured survey questionnaire was used to determine consumers' preferences and behavior with regard to horse meat at a horse meat restaurant located in Jeju, Korea, from October 1 to December 24, 2005. The questionnaire employed in this study consisted of 20 questions designed to characterize six general attributes: horse meat sensory property, physical appearance, health condition, origin, price, and other attributes. Of the 1370 questionnaires distributed, 1126 completed questionnaires were retained based on the completeness of the answers, representing an 82.2% response rate. Two issues were investigated that might facilitate the search for ways to improve horse meat production and marketing programs in Korea. The first step was to determine certain important factors, called principal components, which enabled the researchers to understand the needs of horse meat consumers via principal component analysis. The second step was to define consumer segments with regard to their preferences for horse meat, which was accomplished via cluster analysis. The results of the current study showed that health condition, price, origin, and leanness were the most critical physical attributes affecting the preferences of horse meat consumers. Four segments of consumers, with different demands for horse meat attributes, were identified: origin-sensitive consumers, price-sensitive consumers, quality and safety-sensitive consumers, and non-specific consumers. Significant differences existed among segments of consumers in terms of age, nature of work, frequency of consumption, and general level of acceptability of horse meat. PMID:20163664

Oh, Woon Yong; Lee, Ji Woong; Lee, Chong Eon; Ko, Moon Seok; Jeong, Jae Hong

2009-12-01

39

School Motivation Questionnaire for the Portuguese population: structure and psychometric studies.  

PubMed

It is presented the structure and psychometric studies of the "School Motivation Questionnaire". The SMQ is a self-report questionnaire with 101 items, organized in sixteen scales that measure the students' goal orientations, the perceived classroom goal structures, the perceived teacher's autonomy support and the use of learning strategies. Twelve scales are adapted from the "Learning Climate Questionnaire", "Perceptions of Instrumentality" and "Cuestionário a Estudiantes". Four scales and five additional items are created new. The psychometric studies rely on a convenience sample consisting of 9th and 12th grade students (N = 485) of Portuguese schools. The factorial and construct validity, verified through several exploratory factorial analyses to the data, presents a final solution of six factors, labelled Strategies (F1), Teacher Extrinsic Goals (F2), Student Extrinsic Goals, Externally Regulated (F3) Teacher Intrinsic Goals (F4), Student Extrinsic Goals, Internally Regulated (F5), and Student Intrinsic Goals (F6). The six-factor solution explains a significant variance of the scale results (53.95%). Good coefficients of internal consistency are obtained for all factors, never below (.858; F6). In sum there is strong evidence to support the multi-dimensionality of SMQ, upholding that the data obtained is exploratory and applies for future validation studies. PMID:23156946

Cordeiro, Pedro Miguel Gomes; Figueira, Ana Paula Couceiro; da Silva, José Tomás; Matos, Lennia

2012-11-01

40

Evaluation of adherence to oral antiviral hepatitis B treatment using structured questionnaires  

PubMed Central

AIM: To assess adherence rates to nucleos(t)ide analogues (NUCs) therapy in patients with chronic hepatitis B virus infection and determine factors associated with adherence. METHODS: The questionnaire study was conducted in the liver clinics at Concord Repatriation General Hospital. All patients who were currently taking one or more NUCs were asked to complete a structured, self-administered 32-item questionnaire. Adherence was measured using visual analogue scales. The patient’s treating clinician was also asked to assess their patient’s adherence via a structured questionnaire. RESULTS: A total of 80 patients completed the questionnaire. Sixty six percent of the patients (n = 49) reported optimal adherence whilst 25 (33.8%) graded their adherence to NUCs as suboptimal. Thirty four (43%) patients reported to have omitted taking their NUCs sometime in the past. Recent non-adherence was uncommon. Amongst the patients who reported skipping medications, the most common reason cited was ”forgetfulness“ (n = 27, 56.25%). Other common reasons included: ran out of medications (n = 5, 10.42%), being too busy (n = 4, 8.33%) and due to a change in daily routine (n = 5, 10.42%). Patients who reported low adherence to other prescription pills were also more likely to miss taking NUCs (P = 0.04). Patients who were under the care of a language-discordant clinician were also more likely to report suboptimal adherence to NUCs (P = 0.04). CONCLUSION: Adherence rates were much less than that expected by the physician and has potential adverse affect on long term outcome. Communication and education appear central and strategies need to be implemented to improve ongoing adherence. PMID:22400085

Giang, Leesa; Selinger, Christian P; Lee, Alice Unah

2012-01-01

41

Model Specification Searches in Structural Equation Modeling Using Tabu Search.  

ERIC Educational Resources Information Center

Introduces an alternative structural equation modeling (SEM) specification search approach based on the Tabu search procedure. Using data with known structure, the procedure is illustrated, and its capabilities for specification searches in SEM are demonstrated. (Author/SLD)

Marcoulides, George A.; Drezner, Zvi; Schumacker, Randall E.

1998-01-01

42

Validation of the factor structure of the Greek adaptation of the Sociocultural Attitudes Towards Appearance Questionnaire (SATAQ-3).  

PubMed

The current study aimed to confirm the factor structure and reliability of the newly translated Greek version of the Sociocultural Attitudes Towards Appearance Questionnaire-3 (SATAQ-3) among 1753 Greek-Cypriot high school students. Results of the structural equation modeling indicated a very good fit with the original four-factor structure of the SATAQ-3 for both males and females. The Cronbach's alpha coefficients for the four subscales were .92 for 'Internalization-General', .82 for 'Internalization-Athlete', .94 for 'Pressure' and .88 for 'Information'. Further analyses showed no significant differences between BMI categories with respect to the Internalization-General, Internalization-Athlete and Information factors but there were significant differences on the Pressure factor. The findings of the current study support the existence of the original four-factor structure of the SATAQ-3. The validity and reliability results of the Greek version of the SATAQ-3 support its use in Greek-speaking countries or populations. PMID:24958653

Argyrides, Marios; Kkeli, Natalie; Kendeou, Panayiota

2014-06-01

43

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. PMID:22891727

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

2012-01-01

44

Static Analysis of Tensegrity Structures Part 1. Equilibrium Equations  

E-print Network

Static Analysis of Tensegrity Structures Part 1. Equilibrium Equations Julio Correa Joseph Duffy of an antiprism tensegrity structure subjected to a wide variety of external loads is addressed. The virtual work. Introduction Tensegrity structures are spatial structures formed by a combination of rigid elements (the struts

Florida, University of

45

Childhood Trauma Questionnaire: factor structure, measurement invariance, and validity across emotional disorders.  

PubMed

To study the psychometric properties of the Childhood Trauma Questionnaire-Short Form (CTQ-SF), we determined its dimensional structure, measurement invariance across presence of emotional disorders, the association of the CTQ-SF with an analogous interview-based measure (CTI) across presence of emotional disorders, and the incremental value of combining both instruments in determining associations with severity of psychopathology. The sample included 2,308 adults, ages 18-65, consisting of unaffected controls and chronically affected and intermittently affected persons with an emotional disorder at Time 0 (T0) or 4 years later at T4. Childhood maltreatment was measured at T0 with an interview and at T4 with the CTQ-SF. At each wave, patients were assessed for Diagnostic and Statistical Manual of Mental Disorders (4th ed., or DSM-IV; American Psychiatric Association, 1994)-based emotional disorders (Composite Interview Diagnostic Instrument) and symptom severity (Inventory of Depressive Symptomatology, Beck Anxiety Inventory, Fear Questionnaire). Besides the correlated original 5-factor solution, an indirect higher order and direct bifactorial model also showed a good fit to the data. The 5-factor solution proved to be invariant across disordered-control comparison groups. The CTQ-SF was moderately associated with the CTI, and this association was not attenuated by disorder status. The CTQ-SF was more sensitive in detecting emotional abuse and emotional neglect than the CTI. Combined CTQ-SF/CTI factor scores showed a higher association with severity of psychopathology. We conclude that although the original 5-factor model fits the data well, results of the hierarchical analyses suggest that the total CTQ scale adequately captures a broad dimension of childhood maltreatment. A 2-step measurement approach in the assessment of childhood trauma is recommended in which screening by a self-report questionnaire is followed by a (semi-)structured diagnostic interview. PMID:24773037

Spinhoven, Philip; Penninx, Brenda W; Hickendorff, Marian; van Hemert, Albert M; Bernstein, David P; Elzinga, Bernet M

2014-09-01

46

Integrable structures for a generalized Monge-Ampère equation  

NASA Astrophysics Data System (ADS)

We consider a third-order generalized Monge-Ampère equation uyyy - u{xxy/ 2 } + uxxxuxyy = 0, which is closely related to the associativity equation in two-dimensional topological field theory. We describe all integrable structures related to it: Hamiltonian, symplectic, and also recursion operators. We construct infinite hierarchies of symmetries and conservation laws.

Verbovetsky, A. M.; Vitolo, R.; Kersten, P.; Krasil'shchik, I. S.

2012-05-01

47

Factor structure of the Singapore English version of the KINDL® children quality of life questionnaire  

PubMed Central

Background Quality of life (QoL) outcomes are useful in the assessment of physical, mental and social well-being and for informed healthcare decision making. However, few studies have evaluated QoL issues among Asian children due largely to the lack of culturally valid and reliable QoL questionnaires. Hence, we aimed to report the psychometric properties, in particular factor structure, of KINDL (Singapore) questionnaires among school-going children. Methods Students aged 8–16 years from participating schools were selected by convenience sampling. Subjects self-completed KINDL-Kid (Singapore) and KINDL-Kiddo (Singapore) questionnaires, which were cross-culturally adapted from KINDL (Germany English) for use in Singapore. We evaluated floor and ceiling effects, internal consistency and performed factor analysis. Results A total of 328 respondents (mean (SD) age: 9.6 (1.31) years; 67% female; 75% Chinese, 16% Malays, 9% Indians and others) completed KINDL-Kid while 1,026 respondents (mean (SD) age: 14.0 (1.00) years; 82% female; 82% Chinese, 12% Malays; 6% Indians and others) completed KINDL-Kiddo. Mean (SD) TOTAL QoL score was 65.5 (12.76) and 56.6 (11.92) for KINDL-Kid and KINDL-Kiddo, respectively. Floor and ceiling effects were important in five of six KINDL-Kid and two of six KINDL-Kiddo subscales. Reliability coefficients ranged from 0.40 to 0.71 (KINDL-Kid) and 0.44 to 0.84 (KINDL-Kiddo). Factor analysis generated eight and seven factors in KINDL-Kid and KINDL-Kiddo, respectively. Conclusion KINDL-Kiddo exhibited good psychometric properties and may be used to assess QoL in this multi-ethnic English-speaking Asian population. However, psychometric properties of KINDL-Kid may need to be improved either by developing new items or modifying existing items. PMID:17239229

Wee, Hwee-Lin; Ravens-Sieberer, Ulrike; Erhart, Michael; Li, Shu-Chuen

2007-01-01

48

The Lorents-Dirac equation and the structure of spacetime  

E-print Network

A new interpretation of the causality implementation in the Lienard-Wiechert solution raises new doubts against the validity of the Lorentz-Dirac equation and the limits of validity of the Minkowski structure of spacetime.

Manoelito M. de Souza

1995-05-26

49

The Lorentz-Dirac equation and the structure of spacetime  

E-print Network

A new interpretation of the causality implementation in the Lienard-Wiechert solution raises new doubts against the validity of the Lorentz-Dirac equation and the limits of validity of the Minkowski structure of spacetime.

De Souza, M M

1995-01-01

50

Nonlinear structural equation modeling: is partial least squares an alternative?  

Microsoft Academic Search

Nonlinear structural equation modeling provides many advantages over analyses based on manifest variables only. Several approaches\\u000a for the analysis of latent interaction effects have been developed within the last 15 years, including the partial least squares\\u000a product indicator approach (PLS-PI), the constrained product indicator approach using the LISREL software (LISREL-PI), and\\u000a the distribution-analytic latent moderated structural equations approach (LMS) using

Karin Schermelleh-Engel; Christina S. Werner; Andreas G. Klein; Helfried Moosbrugger

2010-01-01

51

The Otitis Media-6 questionnaire: psychometric properties with emphasis on factor structure and interpretability  

PubMed Central

Background The Otitis Media-6 questionnaire (OM-6) is the most frequently used instrument to measure health related quality of life in children with otitis media. The main objectives of this study are 1) to translate and cross-culturally adapt the OM-6 into Danish, and 2) to assess important psychometric properties including structural validity and interpretability of the OM-6 in a Danish population of children suffering from otitis media. Methods The OM-6 was translated and cross-culturally adapted according to international guidelines. A longitudinal validation study enrolled 491 children and their families, and the measurement properties of the OM-6 were evaluated using the Cosmin taxonomy. The properties assessed were construct and structural validity (confirmatory factor analysis) including internal consistency, reproducibility (test-retest reliability and smallest detectable change), responsiveness and interpretability. Results A total of 435 children were eligible to participate in the study. Analyses of structural validity and internal consistency indicated that parent appraisal of hearing and speech problems may be problematic. Both scales showed similarly good test-retest reliability and construct validity, were able to discriminate between diagnostic subgroups and responsive to change. Cut-off values of 16.7 and 30.0 were found to represent minimal important change for the patients. Conclusions The Danish version of the OM-6 is a reliable, valid, responsive and interpretable questionnaire to measure quality of life in children with otitis media. This study sheds light on possible weaknesses of the instrument that needs to be acknowledged in the utilization of the instrument. However, despite these issues our results support the continuing use of OM-6 as a 1-factor functional health scale with a separate global health rating. Furthermore, indications of values representing minimal important change as perceived by the respondent are presented. PMID:24257471

2013-01-01

52

Factor structure and validity of the Medication Adherence Questionnaire (MAQ) with cigarette smokers trying to quit  

PubMed Central

The Medication Adherence Questionnaire (MAQ) is a scale used to evaluate adherence to medications. The present study assessed the factor structure and validity of the MAQ with cigarette smokers. A principal components analysis was conducted on MAQ scores from a sample of smokers presenting for treatment in a clinical trial of naltrexone and nicotine patch for smoking cessation (N=385). Indices of convergent and predictive validity were tested using electronic medication caps for naltrexone, nicotine patch counts, plasma drug levels of naltrexone, and treatment outcomes. The principal components analysis revealed two factors. Factor 1, labeled “unintentional nonadherence,” measured the extent to which individuals were nonadherent because they were careless or forgot to take their medications. Factor 2, labeled “purposeful nonadherence,” assessed nonadherence related to purposefully stopping medication use after feeling better or worse. Only the second factor was shown to have good convergent and predictive validity. Specifically, this factor was related to pill-taking behavior measured with electronic medication caps and drug plasma levels and nicotine patch use based on nicotine patch count data, and it was associated with smoking cessation outcome. Thus the purposeful nonadherence factor of the MAQ may be used as a brief screening tool for medication adherence with cigarette smokers seeking treatment. Information obtained with this questionnaire could be used to counsel patients regarding the importance of medication adherence. PMID:17454716

Toll, Benjamin A.; McKee, Sherry A.; Martin, Daniel J.; Jatlow, Peter; O'Malley, Stephanie S.

2008-01-01

53

The factor structure of the 12-item General Health Questionnaire in a literate Kenyan population.  

PubMed

The study evaluated the factorial structure of the 12-item General Health Questionnaire (GHQ-12) in a population of Kenyan adults and adolescents. A sample of 1216 people aged 12-60?years completed the English version of the GHQ-12. To evaluate the factor structure of the GHQ-12, a confirmatory analysis using MPLUS was carried out. A unidimensional model of GHQ-12 as originally conceptualized did not provide a good fit for the data (Comparative Fit Index?=?0.843, Tuckler Lewis Index?=?0.841, Root Mean Square of Error Approximation?=?0.078, Standardized Root Mean Square Residual?=?0.063). Unidimensional models, which partial out the effects of negative wording showed an adequate fit to the data. Additionally, multidimensional models showed an excellent fit to the data. Based on the principles of parsimony, pattern of item loading and the correlation between identified factors in the multidimensional models, it was concluded that the GHQ-12 is a unidimensional measure whose structure is significantly influenced by wording effects. The GHQ-12, when applied to a literate population in Africa, showed similar factor structure as in other regions of the world; hence, it can be recommended for use as a screening tool for general symptoms of psychological distress. PMID:22282374

Abubakar, A; Fischer, R

2012-08-01

54

Wording effects and the factor structure of the 12-item General Health Questionnaire (GHQ-12).  

PubMed

The 12-item version of the General Health Questionnaire (GHQ-12) has become a popular screening instrument with which to measure general psychological health in different settings. Previous studies into the factorial structure of the GHQ-12 have mainly supported multifactor solutions, and only a few recent works have shown that the GHQ-12 was best represented by a single substantive factor when method effects associated with negatively worded items were considered. Confirmatory factor analysis was applied to compare competing measurement models from previous research, including correlated traits-correlated methods and correlated traits-correlated uniquenesses approaches, to obtain further evidence about the factorial structure of the GHQ-12. This goal was achieved with data from 3,050 participants who completed the GHQ-12 included in the Catalonian Survey of Working Conditions (Catalonian Labor Relations and Quality of Work Department, 2012). The results showed additional evidence that the GHQ-12 has a unidimensional structure after controlling for method effects associated with negatively worded items. Furthermore, we found evidence for our hypothesis about the spurious nature of the 3-factor solution in Graetz's (1991) model after comparing its fit with that found for alternative models resulting from different combinations of the negatively worded items. An implication of our results is that future research about the factor structure of the GHQ-12 should take method effects associated with negative wording into account in order to avoid reaching inaccurate conclusions about its dimensionality. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24708077

Molina, J Gabriel; Rodrigo, Maria F; Losilla, Josep-Maria; Vives, Jaume

2014-09-01

55

Eating Disorder Examination-Questionnaire Factor Structure and Construct Validity In Bariatric Surgery Candidates  

PubMed Central

Objective The Eating Disorder Examination-Questionnaire (EDE-Q) is increasingly used in studies with bariatric surgery patients although little is known about psychometric properties of this self-report measure in this clinical group. The current study evaluated the factor structure and construct validity of the EDE-Q in bariatric surgery candidates. Methods Participants were a consecutive series of 174 obese bariatric surgery candidates who completed the EDE-Q and a battery of behavioral and psychological measures. Results Confirmatory factor analysis (CFA) revealed an inadequate fit for the original EDE-Q structure but revealed a good fit for an alternative structure suggested by recent research with obese samples. CFA supported a 7-item, 3-factor structure; the three factors were interpreted as dietary restraint, shape/weight overvaluation, and body dissatisfaction. The three factors converged with other relevant collateral measures. Conclusions These factor analytic findings, which replicate recent findings from studies with diverse obese samples, demonstrated convergent validity. Implications of these findings for clinical assessment and research with bariatric surgery patients are discussed. PMID:23229951

Grilo, Carlos M.; Henderson, Kathryn E.; Bell, Robert L.; Crosby, Ross D.

2012-01-01

56

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

PubMed Central

To examine the factor structure of temperament in 5 – 10-year-olds with Williams syndrome (WS), an exploratory factor analysis was conducted on the responses of parents of 192 children on the Children’s Behavior Questionnaire (CBQ). Four factors were identified. Two corresponded to factors reported for typically developing children: Effortful Control and Extraversion/Surgency and two corresponded to the temperament constructs of withdrawal/inhibition and irritability/frustration and activity, observed in typically-developing infants. Parents of 109 of the 192 participants also completed the Anxiety Disorders Interview Schedule, Parent version. Children with an anxiety disorder other than specific phobia differed significantly from children without an anxiety disorder on all factors except Extraversion/Surgency. Children with ADHD differed significantly from children without ADHD on Effortful Control and Extraversion/Surgency. PMID:22371147

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

2012-01-01

57

Examining the factor structures of the five facet mindfulness questionnaire and the self-compassion scale.  

PubMed

The five facet mindfulness questionnaire (FFMQ; Baer, Smith, Hopkins, Krietemeyer, & Toney, 2006) and the self-compassion scale (SCS; Neff, 2003) are widely used measures of mindfulness and self-compassion in mindfulness-based intervention research. The psychometric properties of the FFMQ and the SCS need to be independently replicated in community samples and relevant clinical samples to support their use. Our primary aim was to establish the factor structures of the FFMQ and SCS in individuals with recurrent depression in remission, since mindfulness-based cognitive therapy (MBCT) was developed as a treatment for preventing depressive relapse. In order to determine the consistency across populations, we examined the factor structures of the FFMQ and SCS in 3 samples: (1) a convenience sample of adults, (2) a sample of adults who practice meditation, and (3) a sample of adults who suffer from recurrent depression and were recruited to take part in a trial of MBCT. Confirmatory factor analyses (CFAs) showed that a 4-factor hierarchical model of the FFMQ best fits the community sample and the clinical sample but that a 5-factor hierarchical model of the FFMQ best fits the meditator sample. CFA did not endorse the SCS 6-factor hierarchical structure in any of the 3 samples. Clinicians and researchers should be aware of the psychometric properties of the FFMQ to measure mindfulness when comparing meditators and nonmeditators. Further research is needed to develop a more psychometrically robust measure of self-compassion. PMID:24490681

Williams, Matthew J; Dalgleish, Tim; Karl, Anke; Kuyken, Willem

2014-06-01

58

On Nonequivalence of Several Procedures of Structural Equation Modeling  

ERIC Educational Resources Information Center

The normal theory based maximum likelihood procedure is widely used in structural equation modeling. Three alternatives are: the normal theory based generalized least squares, the normal theory based iteratively reweighted least squares, and the asymptotically distribution-free procedure. When data are normally distributed and the model structure…

Yuan, Ke-Hai; Chan, Wai

2005-01-01

59

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

60

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

61

Structure-Preserving Model Order Reduction of RCL Circuit Equations  

E-print Network

Structure-Preserving Model Order Reduction of RCL Circuit Equations Roland W. Freund Department circuit. In this paper, we describe the problem of structure-preserving model order reduction of general-order model to maintain the passivity properties of the orig- inal circuit. In [23, 24, 4], it is shown

Freund, Roland W.

62

Critical Factors Analysis for Offshore Software Development Success by Structural Equation Modeling  

NASA Astrophysics Data System (ADS)

In order to analyze the success/failure factors in offshore software development service by the structural equation modeling, this paper proposes to follow two approaches together; domain knowledge based heuristic analysis and factor analysis based rational analysis. The former works for generating and verifying of hypothesis to find factors and causalities. The latter works for verifying factors introduced by theory to build the model without heuristics. Following the proposed combined approaches for the responses from skilled project managers of the questionnaire, this paper found that the vendor property has high causality for the success compared to software property and project property.

Wada, Yoshihisa; Tsuji, Hiroshi

63

A stiffness equation transfer method for natural frequencies of structures  

Microsoft Academic Search

A stiffness equation transfer method is proposed for obtaining vibration frequencies of structures. This method is an extension of the finite element-transfer matrix (FE-TM) method. In the present method, the transfer of state vectors from left to right in the ordinary FE-TM method is changed into the transfer of stiffness equations of every section from left to right. This method

Huiyu Xue

2003-01-01

64

Inverse variational problem and canonical structure of Burgers equations  

NASA Astrophysics Data System (ADS)

It is demonstrated that Burgers equations, which are often believed to describe dissipative systems, are non-Lagrangian. Following Bateman's analysis of damped harmonic oscillator an action is defined to look for a Lagrangian representation for equations in the Burgers hierarchy. The associated higher-order Lagrangian densities are found to be degenerate such that the Hamiltonian structure could be studied by a repackaging of Ostrogradski formalism and Dirac's theory of constraints.

Talukdar, B.; Ghosh, S.; Das, U.

2005-04-01

65

On integrable structures for a generalized Monge-Ampere equation  

Microsoft Academic Search

We consider a 3rd-order generalized Monge-Ampere equation u_yyy - u_xxy^2 + u_xxx u_xyy = 0 (which is closely related to the associativity equation in the 2-d topological field theory) and describe all integrable structures related to it (i.e., Hamiltonian, symplectic, and recursion operators). Infinite hierarchies of symmetries and conservation laws are constructed as well.

Paul Kersten; Iosif Krasil'shchik; Alexander Verbovetsky; Raffaele Vitolo

2011-01-01

66

A Confirmatory Approach to Examining the Factor Structure of the Strengths and Difficulties Questionnaire (SDQ): A Large Scale Cohort Study  

ERIC Educational Resources Information Center

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…

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

2013-01-01

67

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

ERIC Educational Resources Information Center

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…

Palmieri, Patrick A.; Smith, Gregory C.

2007-01-01

68

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

69

Comparing the factor structure of the Wisconsin Schizotypy Scales and the Schizotypal Personality Questionnaire.  

PubMed

Schizotypy is a multidimensional construct that captures the expression of schizophrenic symptoms and impairment from subclinical levels to full-blown psychosis. The present study examined the comparability of the factor structure of 2 leading psychometric measures of schizotypy: the Wisconsin Schizotypy Scales (WSS) and the Schizotypal Personality Questionnaire (SPQ). Both the SPQ and WSS purportedly capture the multidimensional structure of schizotypy; however, whether they are measuring comparable factors has not been empirically demonstrated. This study provided support for a 2-factor model with positive and negative factors underlying the WSS; however, contrary to previous findings, the best fit for the SPQ was for a 4-factor model using confirmatory factor analysis, and a 2-factor model using exploratory factor analysis. The WSS factors were relatively distinct, whereas those underlying the SPQ showed high overlap. The WSS positive and SPQ cognitive-perceptual factors appeared to tap comparable constructs. However, the WSS negative and SPQ interpersonal factors appeared to tap somewhat different constructs based on their correlation and their patterns of associations with other schizotypy dimensions and the Five-Factor Model-suggesting that the SPQ interpersonal factor may not adequately tap negative or deficit schizotypy. Although the SPQ offers the advantage over the WSS of having a disorganization factor, it is not clear that this SPQ factor is actually distinct from positive schizotypy. Existing measures should be used with caution and new measures based on a priori theories are necessary to further understand the factor structure of schizotypy. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25314229

Gross, Georgina M; Mellin, Juliann; Silvia, Paul J; Barrantes-Vidal, Neus; Kwapil, Thomas R

2014-10-01

70

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

PubMed

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 analog 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. PMID:19423243

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

2009-07-01

71

Killing-Yano equations and G-structures  

E-print Network

We solve the Killing-Yano equation on manifolds with a $G$-structure for $G=SO(n), U(n), SU(n), Sp(n)\\cdot Sp(1), Sp(n), G_2$ and $Spin(7)$. Solutions include nearly-K\\"ahler, weak holonomy $G_2$, balanced SU(n) and holonomy $G$ manifolds. As an application, we find that particle probes on $AdS_4\\times X$ compactifications of type IIA and 11-dimensional supergravity admit a ${\\cal W}$-type of symmetry generated by the fundamental forms. We also explore the ${\\cal W}$-symmetries of string and particle actions in heterotic and common sector supersymmetric backgrounds. In the heterotic case, the generators of the ${\\cal W}$-symmetries completely characterize the solutions of the gravitino Killing spinor equation, and the structure constants of the ${\\cal W}$-symmetry algebra depend on the solution of the dilatino Killing spinor equation.

G. Papadopoulos

2007-12-04

72

Consistent partial least squares for nonlinear structural equation models.  

PubMed

Partial Least Squares as applied to models with latent variables, measured indirectly by indicators, is well-known to be inconsistent. The linear compounds of indicators that PLS substitutes for the latent variables do not obey the equations that the latter satisfy. We propose simple, non-iterative corrections leading to consistent and asymptotically normal (CAN)-estimators for the loadings and for the correlations between the latent variables. Moreover, we show how to obtain CAN-estimators for the parameters of structural recursive systems of equations, containing linear and interaction terms, without the need to specify a particular joint distribution. If quadratic and higher order terms are included, the approach will produce CAN-estimators as well when predictor variables and error terms are jointly normal. We compare the adjusted PLS, denoted by PLSc, with Latent Moderated Structural Equations (LMS), using Monte Carlo studies and an empirical application. PMID:24306555

Dijkstra, Theo K; Schermelleh-Engel, Karin

2014-10-01

73

Using structural equation modeling to investigate relationships among ecological variables  

Microsoft Academic Search

Structural equation modeling is an advanced multivariate statistical process with which a researcher can construct theoretical concepts, test their measurement reliability, hypothesize and test a theory about their relationships, take into account measurement errors, and consider both direct and indirect effects of variables on one another. Latent variables are theoretical concepts that unite phenomena under a single term, e.g., ecosystem

Ziad A. Malaeb; J. Kevin Summers; Bruce H. Pugesek

2000-01-01

74

The relativistic equations of stellar structure and evolution  

NASA Technical Reports Server (NTRS)

The general relativistic equations of stellar structure and evolution are reformulated in a notation which makes easy contact with Newtonian theory. A general relativistic version of the mixing-length formalism for convection is presented. It is argued that in work on spherical systems, general relativity theorists have identified the wrong quantity as total mass-energy inside radius r.

Thorne, K. S.

1975-01-01

75

Testing Structural Equation Models or Detection of Misspecifications?  

ERIC Educational Resources Information Center

Assessing the correctness of a structural equation model is essential to avoid drawing incorrect conclusions from empirical research. In the past, the chi-square test was recommended for assessing the correctness of the model but this test has been criticized because of its sensitivity to sample size. As a reaction, an abundance of fit indexes…

Saris, Willem E.; Satorra, Albert; van der Veld, William M.

2009-01-01

76

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

77

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 dynamically…

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

2011-01-01

78

Latent Growth Curves within Developmental Structural Equation Models.  

ERIC Educational Resources Information Center

Uses structural equation modeling to combine traditional ideas from repeated-measures ANOVA with some traditional ideas from longitudinal factor analysis. The model describes a latent growth curve model that permits the estimation of parameters representing individual and group dynamics. (Author/RH)

McArdle, J. J.; Epstein, David

1987-01-01

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

Implementing Restricted Maximum Likelihood Estimation in Structural Equation Models  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) is now a generic modeling framework for many multivariate techniques applied in the social and behavioral sciences. Many statistical models can be considered either as special cases of SEM or as part of the latent variable modeling framework. One popular extension is the use of SEM to conduct linear mixed-effects…

Cheung, Mike W.-L.

2013-01-01

81

Multiple Imputation Strategies for Multiple Group Structural Equation Models  

ERIC Educational Resources Information Center

Although structural equation modeling software packages use maximum likelihood estimation by default, there are situations where one might prefer to use multiple imputation to handle missing data rather than maximum likelihood estimation (e.g., when incorporating auxiliary variables). The selection of variables is one of the nuances associated…

Enders, Craig K.; Gottschall, Amanda C.

2011-01-01

82

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

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

Asymptotic Biases in Exploratory Factor Analysis and Structural Equation Modeling  

ERIC Educational Resources Information Center

Formulas for the asymptotic biases of the parameter estimates in structural equation models are provided in the case of the Wishart maximum likelihood estimation for normally and nonnormally distributed variables. When multivariate normality is satisfied, considerable simplification is obtained for the models of unstandardized variables. Formulas…

Ogasawara, Haruhiko

2004-01-01

85

Analyzing Mixed-Dyadic Data Using Structural Equation Models  

ERIC Educational Resources Information Center

Mixed-dyadic data, collected from distinguishable (nonexchangeable) or indistinguishable (exchangeable) dyads, require statistical analysis techniques that model the variation within dyads and between dyads appropriately. The purpose of this article is to provide a tutorial for performing structural equation modeling analyses of cross-sectional…

Peugh, James L.; DiLillo, David; Panuzio, Jillian

2013-01-01

86

Bootstrap Estimation of Sample Statistic Bias in Structural Equation Modeling.  

ERIC Educational Resources Information Center

This study empirically investigated bootstrap bias estimation in the area of structural equation modeling (SEM). Three correctly specified SEM models were used under four different sample size conditions. Monte Carlo experiments were carried out to generate the criteria against which bootstrap bias estimation should be judged. For SEM fit indices,…

Thompson, Bruce; Fan, Xitao

87

Testing Parameters in Structural Equation Modeling: Every One Matters  

Microsoft Academic Search

A problem with standard errors estimated by many structural equation modeling programs is described. In such programs, a parameter's standard error is sensitive to how the model is identified (i.e., how scale is set). Alternative but equivalent ways to identify a model may yield different standard errors, and hence different Z tests for a parameter, even though the identifications produce

Richard Gonzalez; Dale Griffin

2001-01-01

88

Bayesian Data-Model Fit Assessment for Structural Equation Modeling  

ERIC Educational Resources Information Center

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…

Levy, Roy

2011-01-01

89

Structural Equation Modeling: Foundations and Extensions [book review].  

ERIC Educational Resources Information Center

This book, which is designed for those already familiar with the basic principles of structural equation modeling (SEM), discusses the progress and unfolding of SEM since the 1990s. After a compact treatment of underlying theory, the author illustrates many such issues with a discussion of his own SEM research. (SLD)

Boomsma, Anne

2003-01-01

90

People Are Variables Too: Multilevel Structural Equations Modeling  

ERIC Educational Resources Information Center

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…

Mehta, Paras D.; Neale, Michael C.

2005-01-01

91

Advanced Applications of Structural Equation Modeling in Counseling Psychology Research  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) is a data-analytic technique that allows researchers to test complex theoretical models. Most published applications of SEM involve analyses of cross-sectional recursive (i.e., unidirectional) models, but it is possible for researchers to test more complex designs that involve variables observed at multiple…

Martens, Matthew P.; Haase, Richard F.

2006-01-01

92

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 model…

Pek, Jolynn; MacCallum, Robert C.

2011-01-01

93

Introduction to Structural Equation Modeling: Issues and Practical Considerations  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) is a versatile statistical modeling tool. Its estimation techniques, modeling capacities, and breadth of applications are expanding rapidly. This module introduces some common terminologies. General steps of SEM are discussed along with important considerations in each step. Simple examples are provided to…

Lei, Pui-Wa; Wu, Qiong

2007-01-01

94

The Use of Structural Equation Modeling in Counseling Psychology Research  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) has become increasingly popular for analyzing data in the social sciences, although several broad reviews of psychology journals suggest that many SEM researchers engage in questionable practices when using the technique. The purpose of this study is to review and critique the use of SEM in counseling psychology…

Martens, Matthew P.

2005-01-01

95

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

96

A Note on Structural Equation Modeling Estimates of Reliability  

ERIC Educational Resources Information Center

Reliability can be estimated using structural equation modeling (SEM). Two potential problems with this approach are that estimates may be unstable with small sample sizes and biased with misspecified models. A Monte Carlo study was conducted to investigate the quality of SEM estimates of reliability by themselves and relative to coefficient…

Yang, Yanyun; Green, Samuel B.

2010-01-01

97

Local Influence Analysis of Nonlinear Structural Equation Models  

ERIC Educational Resources Information Center

By regarding the latent random vectors as hypothetical missing data and based on the conditional expectation of the complete-data log-likelihood function in the EM algorithm, we investigate assessment of local influence of various perturbation schemes in a nonlinear structural equation model. The basic building blocks of local influence analysis…

Lee, Sik-Yum; Tang, Nian-Sheng

2004-01-01

98

Testable Implications of Linear Structural Equation Models Bryant Chen  

E-print Network

structural equation model (SEM) rely on the likelihood ra- tio or chi-square test which simultaneously tests ratio or chi-square test that compares the covariance matrix implied by the model that a global chi-square test Copyright c 2014, Association for the Advancement of Artificial Intelligence (www

California at Los Angeles, University of

99

Testable Implications of Linear Structural Equation Models Bryant Chen  

E-print Network

structural equation model (SEM) rely on the likelihood ratio or chi-square test which simulta- neously tests of testing a model is a likelihood ratio or chi-square test that compares the covariance matrix implied is very large and complex, it is possible that a global chi-square test will not reject the model even

Tian, Jin

100

Model Comparison of Nonlinear Structural Equation Models with Fixed Covariates.  

ERIC Educational Resources Information Center

Proposed a new nonlinear structural equation model with fixed covariates to deal with some complicated substantive theory and developed a Bayesian path sampling procedure for model comparison. Illustrated the approach with an illustrative example using data from an international study. (SLD)

Lee, Sik-Yum; Song, Xin-Yuan

2003-01-01

101

Case-Deletion Diagnostics for Nonlinear Structural Equation Models  

ERIC Educational Resources Information Center

In this article, a case-deletion procedure is proposed to detect influential observations in a nonlinear structural equation model. The key idea is to develop the diagnostic measures based on the conditional expectation of the complete-data log-likelihood function in the EM algorithm. An one-step pseudo approximation is proposed to reduce the…

Lee, Sik-Yum; Lu, Bin

2003-01-01

102

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

103

Structural Equation Models with Continuous and Polytomous Variables.  

ERIC Educational Resources Information Center

A two-stage approach based on the rationale of maximum likelihood and generalized least-squares methods is developed to analyze the general structural equation model for continuous and polytomous variables. Some illustrative examples and a small simulation study (50 replications) are reported. (SLD)

Lee, Sik-Yum; And Others

1992-01-01

104

Maximum Likelihood Estimation of Nonlinear Structural Equation Models.  

ERIC Educational Resources Information Center

Developed an EM type algorithm for maximum likelihood estimation of a general nonlinear structural equation model in which the E-step is completed by a Metropolis-Hastings algorithm. Illustrated the methodology with results from a simulation study and two real examples using data from previous studies. (SLD)

Lee, Sik-Yum; Zhu, Hong-Tu

2002-01-01

105

A Validation Study of the Dutch Childhood Trauma Questionnaire-Short Form: Factor Structure, Reliability, and Known-Groups Validity  

ERIC Educational Resources Information Center

Objective: The 28-item Childhood Trauma Questionnaire-Short Form (CTQ-SF) has been translated into at least 10 different languages. The validity of translated versions of the CTQ-SF, however, has generally not been examined. The objective of this study was to investigate the factor structure, internal consistency reliability, and known-groups…

Thombs, Brett D.; Bernstein, David P.; Lobbestael, Jill; Arntz, Arnoud

2009-01-01

106

The Strengths and Difficulties Questionnaire (SDQ): The Factor Structure and Scale Validation in U.S. Adolescents  

ERIC Educational Resources Information Center

The Strengths and Difficulties Questionnaire (SDQ) is one of the most commonly used instruments for screening psychopathology in children and adolescents. This study evaluated the hypothesized five-factor structure of the SDQ and examined its convergent validity against comprehensive clinical diagnostic assessments. Data were derived from the…

He, Jian-Ping; Burstein, Marcy; Schmitz, Anja; Merikangas, Kathleen R.

2013-01-01

107

Examining the cognitive model of caregiving--a structural equation modelling approach.  

PubMed

The study tests assumptions from the "cognitive model of caregiving" (Kuipers et al., 2010), which aims to inform interventions for carers of people with psychoses. The sample comprised 61 relatives of patients with schizophrenia. Standardized psychological assessments were conducted twice within 6 months including Involvement Evaluation Questionnaire (IEQ-EU), a short form of the Symptom Checklist 90-R (SCL K9), the Family Questionnaire (FQ), scales measuring control attributions of the Illness Perception Questionnaire for Schizophrenia (IPQS-R) and emotions toward the ill relative. Structural equation modelling was used to analyse data. We identified two pathways: (a) from "attributing control to relatives" to distress, intermediated by anxiety for the patient and emotional overinvolvement (EOI), and (b) from "attribution control to patient" to distress, intermediated by anger about the patient and criticism. The model provided a good fit to the data and was successfully replicated at a second point in time. We were able to find supporting evidence for a cognitive model of caregiving. Control attributions and emotions of informal caregivers are important when interventions are planned reducing expressed emotion and burden of caregivers. PMID:24740133

Hesse, Klaus; Klingberg, Stefan

2014-07-30

108

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. PMID:20302668

2010-01-01

109

Understanding discipline in families of children with attention-deficit/hyperactivity disorder: a structural equation model.  

PubMed

One hundred and fifty-five mothers of children with attention deficit/hyperactivity disorder (ADHD) completed a semi-structured interview, the Parenting Stress Index Questionnaire (Abidin, 1990), to evaluate parenting stress. The Parenting Scale (Arnold, O'Leary, Wolff & Acker, 1993) was also administered to measure dysfunctional discipline strategies. Structural equation modeling was used to test a model in which the independent variables were the Child's Characteristics and the Socio-Educational Status of his or her family; intermediate variables were Parenting Stress concerning the Child Domain and concerning the Parent Domain; and the dependent variable was Parental Discipline. The results confirm our hypotheses. Interventions in these families should therefore incorporate a component focused on Parenting Stress (in both the Child Domain and the Parent Domain), as a determinant of Parental Discipline. PMID:19899651

Miranda, Ana; Grau, Dolores; Rosel, Jesús; Meliá, Amanda

2009-11-01

110

Post-partum blues among Korean mothers: a structural equation modelling approach.  

PubMed

The objective of this study was to propose the post-partum blues (PPB) model and to estimate the effects of self-esteem, social support, antenatal depression, and stressful events during pregnancy on PPB. Data were collected from 249 women post-partum during their stay in the maternity units of three hospitals in Korea using a self-administered questionnaire. A structural equation modelling approach using the Analysis of Moments Structure program was used to identify the direct and indirect effects of the variables on PPB. The full model had a good fit and accounted for 70.3% of the variance of PPB. Antenatal depression and stressful events during pregnancy had strong direct effects on PPB. Household income showed indirect effects on PPB via self-esteem and antenatal depression. Social support indirectly affected PPB via self-esteem, antenatal depression, and stressful events during pregnancy. PMID:23009567

Chung, Sung Suk; Yoo, Il Young; Joung, Kyoung Hwa

2013-08-01

111

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. PMID:21861876

2011-01-01

112

Multidisciplinary optimization of controlled space structures with global sensitivity equations  

NASA Technical Reports Server (NTRS)

A new method for the preliminary design of controlled space structures is presented. The method coordinates standard finite element structural analysis, multivariable controls, and nonlinear programming codes and allows simultaneous optimization of the structures and control systems of a spacecraft. Global sensitivity equations are a key feature of this method. The preliminary design of a generic geostationary platform is used to demonstrate the multidisciplinary optimization method. Fifteen design variables are used to optimize truss member sizes and feedback gain values. The goal is to reduce the total mass of the structure and the vibration control system while satisfying constraints on vibration decay rate. Incorporating the nonnegligible mass of actuators causes an essential coupling between structural design variables and control design variables. The solution of the demonstration problem is an important step toward a comprehensive preliminary design capability for structures and control systems. Use of global sensitivity equations helps solve optimization problems that have a large number of design variables and a high degree of coupling between disciplines.

Padula, Sharon L.; James, Benjamin B.; Graves, Philip C.; Woodard, Stanley E.

1991-01-01

113

Reliability and Factor Structure of the Portuguese Version of Self-Reporting Questionnaire  

Microsoft Academic Search

The Self-Reporting Questionnaire is a screening instrument devised by the WHO to identify minor psychiatric morbidity in primary care settings and the community in developing countries. It has already been widely used although its psychometric properties are not yet completely explained. The present article describes the following properties of the Portuguese version of the SRQ-20: a) coefficients of internal consistency;

Eduardo Iacoponi; Jair de Jesus Mari

1989-01-01

114

Factor Structure and Reliability of the Childhood Trauma Questionnaire in a Canadian Undergraduate Student Sample  

ERIC Educational Resources Information Center

Objective: The aims of this study were to examine (1) the psychometric properties of the Childhood Trauma Questionnaire [CTQ; Bernstein, D., Fink, L., Handelsman, L., Foote, J., Lovejoy, M., Wenzel, K., Sapareto, E., & Ruggiero, J. (1994). Initial reliability and validity of a new retrospective measure of child abuse and neglect. American Journal…

Paivio, Sandra, C.; Cramer, Kenneth, M.

2004-01-01

115

The Adult Reading History Questionnaire (ARHQ) in Icelandic: Psychometric Properties and Factor Structure  

ERIC Educational Resources Information Center

This article describes psychometric testing of an Icelandic adaptation of the "Adult Reading History Questionnaire" (ARHQ), designed to detect a history of reading difficulties indicative of dyslexia. Tested in a large and diverse sample of 2,187 adults, the Icelandic adaptation demonstrated internal consistency reliability…

Bjornsdottir, Gyda; Halldorsson, Jonas G.; Steinberg, Stacy; Hansdottir, Ingunn; Kristjansson, Kristleifur; Stefansson, Hreinn; Stefansson, Kari

2014-01-01

116

Psychometric Evidence for the Leisure Interest Questionnaire and Analyses of the Structure of Leisure Interests  

ERIC Educational Resources Information Center

This study provides evidence of reliability and validity for the Leisure Interest Questionnaire (LIQ; J. C. Hansen, 1998). Undergraduate students completed the LIQ and Strong Interest Inventory (SII; E. K. Strong Jr., 1927) at Time 1 and the LIQ 5 weeks later. The internal consistency and test-retest reliability of the LIQ scales were calculated.…

Hansen, Jo-Ida C.; Scullard, Mark G.

2002-01-01

117

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

118

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

119

Preanesthesia Questionnaire  

MedlinePLUS

... this questionnaire accurately and completely. Patient Name ___________________________________________________ Age _________ Weight _______ Height _________ Date _____________ Allergies _______________________________________________________ _______________________________________________________________ Current Medications (Prescription and Non-Prescription -- ...

120

The local Callan-Symanzik equation: structure and applications  

NASA Astrophysics Data System (ADS)

The local Callan-Symanzik equation describes the response of a quantum field theory to local scale transformations in the presence of background sources. The consistency conditions associated with this anomalous equation imply non-trivial relations among the $\\beta$-function, the anomalous dimensions of composite operators and the short distance singularities of correlators. In this paper we discuss various aspects of the local Callan-Symanzik equation and present new results regarding the structure of its anomaly. We then use the equation to systematically write the n-point correlators involving the trace of the energy-momentum tensor. We use the latter result to give a fully detailed proof that the UV and IR asymptotics in a neighbourhood of a 4D CFT must also correspond to CFTs. We also clarify the relation between the matrix entering the gradient flow formula for the $\\beta$-function and a manifestly positive metric in coupling space associated with matrix elements of the trace of the energy momentum tensor.

Baume, Florent; Keren-Zur, Boaz; Rattazzi, Riccardo; Vitale, Lorenzo

2014-08-01

121

Factor Structure of the Penn State Worry QuestionnaireExamination of a Method Factor  

Microsoft Academic Search

The Penn State Worry Questionnaire (PSWQ) was originally designed as a unifactorial measure of pathological trait worry. However, recent studies supported a two-factor solution with positively worded items loading on the first factor and reverse-scored items loading on a second factor. The current study compared this two-factor model to a negative wording method factor solution among college students. A method

Holly Hazlett-Stevens; Jodie B. Ullman; Michelle G. Craske

2004-01-01

122

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

123

Cognitive Error Questionnaire (CEQ): Psychometric Properties and Factor Structure of the German Translation  

Microsoft Academic Search

A central component of Beck et al.’s (1979) cognitive theory of depression is faulty information processing reflected by so-called cognitive errors. These cognitive\\u000a errors are the reason why depressed individuals systematically misinterpret the significance of events in a negative way.\\u000a They are usually assessed with the application of the Cognitive Error Questionnaire (CEQ). This study examines the psychometric\\u000a properties and

Patrick Pössel

2009-01-01

124

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

125

Structure of completely positive quantum master equations with memory kernel  

E-print Network

Semi-Markov processes represent a well known and widely used class of random processes in classical probability theory. Here, we develop an extension of this type of non-Markovian dynamics to the quantum regime. This extension is demonstrated to yield quantum master equations with memory kernels which allow the formulation of explicit conditions for the complete positivity of the corresponding quantum dynamical maps, thus leading to important insights into the structural characterization of the non-Markovian quantum dynamics of open systems. Explicit examples are analyzed in detail.

Heinz-Peter Breuer; Bassano Vacchini

2009-02-13

126

Structure of completely positive quantum master equations with memory kernel  

E-print Network

Semi-Markov processes represent a well known and widely used class of random processes in classical probability theory. Here, we develop an extension of this type of non-Markovian dynamics to the quantum regime. This extension is demonstrated to yield quantum master equations with memory kernels which allow the formulation of explicit conditions for the complete positivity of the corresponding quantum dynamical maps, thus leading to important insights into the structural characterization of the non-Markovian quantum dynamics of open systems. Explicit examples are analyzed in detail.

Breuer, Heinz-Peter

2009-01-01

127

Structure of completely positive quantum master equations with memory kernel.  

PubMed

Semi-Markov processes represent a well-known and widely used class of random processes in classical probability theory. Here, we develop an extension of this type of non-Markovian dynamics to the quantum regime. This extension is demonstrated to yield quantum master equations with memory kernels which allow the formulation of explicit conditions for the complete positivity of the corresponding quantum dynamical maps, thus leading to important insights into the structural characterization of the non-Markovian quantum dynamics of open systems. Explicit examples are analyzed in detail. PMID:19518213

Breuer, Heinz-Peter; Vacchini, Bassano

2009-04-01

128

Modelling functional integration: a comparison of structural equation and dynamic causal models  

E-print Network

Modelling functional integration: a comparison of structural equation and dynamic causal models W. Keywords: Structural equation; Dynamic causal model; Functional integration Introduction Human brain to adhere to two fundamental principles of functional organisation, functional integration and functional

Penny, Will

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

Structural Equation Modeling: Applications in Ecological and Evolutionary Biology Research  

USGS Publications Warehouse

This book presents an introduction to the methodology of structural equation modeling, illustrates its use, and goes on to argue that it has revolutionary implications for the study of natural systems. A major theme of this book is that we have, up to this point, attempted to study systems primarily using methods (such as the univariate model) that were designed only for considering individual processes. Understanding systems requires the capacity to examine simultaneous influences and responses. Structural equation modeling (SEM) has such capabilities. It also possesses many other traits that add strength to its utility as a means of making scientific progress. In light of the capabilities of SEM, it can be argued that much of ecological theory is currently locked in an immature state that impairs its relevance. It is further argued that the principles of SEM are capable of leading to the development and evaluation of multivariate theories of the sort vitally needed for the conservation of natural systems. Supplementary information can be found at the authors website, http://www.jamesbgrace.com/. ? Details why multivariate analyses should be used to study ecological systems ? Exposes unappreciated weakness in many current popular analyses ? Emphasizes the future methodological developments needed to advance our understanding of ecological systems.

Pugesek, Bruce H.; von Eye, Alexander; Tomer, Adrian

2003-01-01

131

Reporting Multiple-Group Mean and Covariance Structure across Occasions with Structural Equation Modeling  

ERIC Educational Resources Information Center

Objectives: Using baseline and second wave data, the study evaluated the measurement and structural properties of parenting stress, personal mastery, and economic strain with N = 381 lower income parents who decided to join and those who did not join in a child development savings account program. Methods: Structural equation modeling mean and…

Okech, David

2012-01-01

132

Desegregation Questionnaire.  

ERIC Educational Resources Information Center

This 47-item questionnaire is designed to measure the examinee's satisfaction or dissatisfaction with various situations occurring in desegregated schools. Administration instructions and a breakdown of the questionnaire into categories and items is included. No field testing has been done. (See also TM 000 940 for a description of the study and…

Mullen, David J.

133

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

134

Cross-cultural validity of the physical self-description questionnaire: comparison of factor structures in Australia, Spain, and Turkey.  

PubMed

We evaluated the cross-cultural generalizability of the factor structure for the Physical Self-Description Questionnaire (PSDQ) using confirmatory factor analysis. The factor structure was reasonably invariant over large samples of responses by Australian, Spanish, and Turkish students. Consistent with a priori predictions, the factor structures based on Australian and Spanish high school students were somewhat more similar to each other than to those based on Turkish university students, but these differences were small. Psychometric, theoretical cross-cultural, and practical considerations support the PSDQ's usefulness in a variety of research and applied settings. The study also provides a model for comparing psychometric properties based on responses to original and translated versions of sport psychology measures. PMID:12230332

Marsh, Herbert W; Marco, Inés Tomás; Abçý, F Hülya

2002-09-01

135

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

NASA Astrophysics Data System (ADS)

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.

Slemrod, M.

1990-12-01

136

The Adult Reading History Questionnaire (ARHQ) in Icelandic: Psychometric Properties and Factor Structure.  

PubMed

This article describes psychometric testing of an Icelandic adaptation of the Adult Reading History Questionnaire (ARHQ), designed to detect a history of reading difficulties indicative of dyslexia. Tested in a large and diverse sample of 2,187 adults, the Icelandic adaptation demonstrated internal consistency reliability (Cronbach's alpha = .92) and test-retest reliability (r = .93). Validity was established by comparing scores of adults who as children received ICD-10 diagnoses of specific reading disorder (F81.0; n = 419) to those of adults defined as nondyslexics (n = 679). ROC curve analysis resulted in an area under the curve of .92 (95% CI = .90, .93, p < .001) and a cutoff score of .43 with sensitivity of 84.5% and specificity of 83.7%. An exploratory factor analysis (n = 2,187) suggested three subscales, Dyslexia Symptoms, Current Reading, and Memory, the mean scores of which differed significantly among diagnosed dyslexics, relatives of dyslexics, and population controls. Our results support the applicability of the ARHQ in Icelandic as a self-report screening tool for adult dyslexia in Iceland. PMID:23456983

Bjornsdottir, Gyda; Halldorsson, Jonas G; Steinberg, Stacy; Hansdottir, Ingunn; Kristjansson, Kristleifur; Stefansson, Hreinn; Stefansson, Kari

2014-11-01

137

Structural precursor to freezing: An integral equation study  

E-print Network

Recent simulation studies have drawn attention to the shoulder which forms in the second peak of the radial distribution function of hard-spheres at densities close to freezing and which is associated with local crystalline ordering in the dense fluid. We address this structural precursor to freezing using an inhomogeneous integral equation theory capable of describing local packing constraints to a high level of accuracy. The addition of a short-range attractive interaction leads to a well known broadening of the fluid-solid coexistence region as a function of attraction strength. The appearence of a shoulder in our calculated radial distribution functions is found to be consistent with the broadened coexistence region for a simple model potential, thus demonstrating that the shoulder is not exclusively a high density packing effect.

J. M. Brader

2008-08-01

138

Review of Ballistic Limit Equations for Composite Structure Walls of Satellites  

Microsoft Academic Search

In this paper a review of existing ballistic limit equations for CFRP (Carbon Fibre Reinforced Plastics) structure walls of satellites is given, and two new ballistic limit equations are presented. The predictive capabilities of the equations are compared to a set of experimental hypervelocity impact test data of CFRP plates and CFRP honeycomb sandwich panels (satellite structure wall) from ENVISAT,

Frank K. Schaefer; E. Schneider; M. Lambert

2004-01-01

139

Validating the Children's Behavior Questionnaire in Dutch children: psychometric properties and a cross-cultural comparison of factor structures.  

PubMed

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 the three broad dimensions of temperament: Surgency/Extraversion, Negative Affectivity, and Effortful Control. For the Standard Form, results demonstrated a relatively high degree of factor similarity of the Dutch sample with other cultures (e.g., China and Japan). The findings provide evidence for applicability of the CBQ in Western Europe as a promising instrument to comprehensively assess reactive and self-regulative temperamental dimensions in young children. PMID:21381838

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

2011-06-01

140

Shock wave structure using nonlinear model Boltzmann equations  

NASA Technical Reports Server (NTRS)

The structure of a strong plane shock wave in a monatomic rarefied perfect gas is one of the simplest problems able to be posed in kinetic theory, and one of the hardest to solve. Its simplicity lies in the absence of solid boundaries, geometrical complications, or internal molecular energy. Its difficulty arises from the great departure of the gas from equilibrium within the shock, which invalidates many of the techniques used successfully elsewhere in kinetic theory. In addition to this theoretical challenge, the modern development of ballistics and hypersonic flight has helped to stimulate extensive theoretical and experimental interest in the shock problem. The experimenters in turn have encountered great difficulties on account of the very small physical dimensions of shocks. In fact, until very recently indeed, any close comparisons of theoretical and experimental shock structure results have been rather unprofitable due to the inadequacies of both theory and experiment. During the last few years this situation has been appreciably improved by development of the Monte Carlo method. This allows idealized 'experiments' to be performed on large computers instead of in wind tunnels, using a known intermolecular force law. The most developed of these methods has been shown to be equivalent theoretically to the Boltzmann equation and to give results which agree extremely closely with measurements of high accuracy. Thus Monte Carlo results not only form the soundest basis for our present theoretical knowledge of shock wave structure, but, for purposes of developing other theories, can also be considered a very valuable experimental resource. However, such results remain very expensive to obtain. In this thesis we develop more economical kinetic theory methods for the approximate prediction of shock structure, and compare our results with those of the Monte Carlo method.

Segal, Ben Maurice

1971-01-01

141

Structural equation modeling: reviewing the basics and moving forward.  

PubMed

This tutorial begins with an overview of structural equation modeling (SEM) that includes the purpose and goals of the statistical analysis as well as terminology unique to this technique. I will focus on confirmatory factor analysis (CFA), a special type of SEM. After a general introduction, CFA is differentiated from exploratory factor analysis (EFA), and the advantages of CFA techniques are discussed. Following a brief overview, the process of modeling will be discussed and illustrated with an example using data from a HIV risk behavior evaluation of homeless adults (Stein & Nyamathi, 2000). Techniques for analysis of nonnormally distributed data as well as strategies for model modification are shown. The empirical example examines the structure of drug and alcohol use problem scales. Although these scales are not specific personality constructs, the concepts illustrated in this article directly correspond to those found when analyzing personality scales and inventories. Computer program syntax and output for the empirical example from a popular SEM program (EQS 6.1; Bentler, 2001) are included. PMID:16856785

Ullman, Jodie B

2006-08-01

142

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.

143

The Strengths and Difficulties Questionnaire (SDQ): the factor structure and scale validation in U.S. adolescents.  

PubMed

The Strengths and Difficulties Questionnaire (SDQ) is one of the most commonly used instruments for screening psychopathology in children and adolescents. This study evaluated the hypothesized five-factor structure of the SDQ and examined its convergent validity against comprehensive clinical diagnostic assessments. Data were derived from the National Comorbidity Survey - Adolescent Supplement (NCS-A), a nationally representative sample of U.S. adolescents aged 13 to 18 years. Parents/parent surrogates (n=6,483) was asked to complete a self-administered questionnaire including the SDQ and DSM-IV comprehensive diagnostic information on the participating adolescents. Confirmatory factor analysis (CFA) was conducted to assess the factor structure of the SDQ. The five-factor solution of the SDQ (including emotional, conduct, hyperactivity-inattention, peer relationship, and prosocial) provided a satisfactory fit to the data, and was invariant across sex, age, race/ethnicity and income subgroups. SDQ scores predicted a significantly increased probability of meeting criteria for a DSM-IV disorder, with better prediction for behavior disorders than for mood disorders. Decreasing the SDQ cutoffs to the 80th percentile significantly increased the sensitivity from 39% to 63% for the SDQ Total Difficulties Score, with an expected decrease in specificity from 93% to 87%. This work confirms the five-factor structure of the SDQ in an ethnically and sociodemogrpahically diverse community sample of adolescents. Our findings strengthen empirical evidence for the use of the parent-reported SDQ as a screening tool for DSM-IV behavioral and emotional disorders in adolescents identified in the general population. PMID:23183936

He, Jian-Ping; Burstein, Marcy; Schmitz, Anja; Merikangas, Kathleen R

2013-05-01

144

From Questionnaire to Conversation: A Structural Intervention to Improve HIV Test Counseling  

PubMed Central

Objectives We describe the effects of structural intervention to enhance the quality of HIV test counseling interaction with men who have sex with men (MSM) in San Francisco. Methods Audio recordings of 28 rapid HIV test sessions by seven counselors were collected in two phases: before and after implementation of a waiting room intervention prior to the session. The sessions were analyzed using sequence maps to visualize and compare the sequence and distribution of four activities: counseling, information delivery, data collection, and sample collection. Results Prior to the intervention, counselors and clients often oriented to data collection about the client’s past risk as if it were a survey. In sessions recorded after the intervention, questions about past risk were dispersed throughout the session and embedded within an elaborated discussion of the client’s particular life circumstances. Conclusion Direct observation with the aid of sequence maps illuminates the ways that counselors and clients collaboratively orient to various tasks. Practice Implications We demonstrated the feasibility of a structural intervention that improved the quality of both counseling and the accuracy of client risk data without requiring additional session time or counselor training. PMID:20888723

Sheon, Nicolas; Lee, Seung-Hee; Facente, Shelley

2010-01-01

145

Nonintegrable semidiscrete Hirota equation: Gauge-equivalent structures and dynamical properties  

NASA Astrophysics Data System (ADS)

In this paper, we investigate nonintegrable semidiscrete Hirota equations, including the nonintegrable semidiscrete Hirota- equation and the nonintegrable semidiscrete Hirota+ equation. We focus on the topics on gauge-equivalent structures and dynamical behaviors for the two nonintegrable semidiscrete equations. By using the concept of the prescribed discrete curvature, we show that, under the discrete gauge transformations, the nonintegrable semidiscrete Hirota- equation and the nonintegrable semidiscrete Hirota+ equation are, respectively, gauge equivalent to the nonintegrable generalized semidiscrete modified Heisenberg ferromagnet equation and the nonintegrable generalized semidiscrete Heisenberg ferromagnet equation. We prove that the two discrete gauge transformations are reversible. We study the dynamical properties for the two nonintegrable semidiscrete Hirota equations. The exact spatial period solutions of the two nonintegrable semidiscrete Hirota equations are obtained through the constructions of period orbits of the stationary discrete Hirota equations. We discuss the topic regarding whether the spatial period property of the solution to the nonintegrable semidiscrete Hirota equation is preserved to that of the corresponding gauge-equivalent nonintegrable semidiscrete equations under the action of discrete gauge transformation. By using the gauge equivalent, we obtain the exact solutions to the nonintegrable generalized semidiscrete modified Heisenberg ferromagnet equation and the nonintegrable generalized semidiscrete Heisenberg ferromagnet equation. We also give the numerical simulations for the stationary discrete Hirota equations. We find that their dynamics are much richer than the ones of stationary discrete nonlinear Schrödinger equations.

Ma, Li-Yuan; Zhu, Zuo-Nong

2014-09-01

146

The Family Strain Index (FSI). Reliability, validity, and factor structure of a brief questionnaire for families of children with ADHD  

Microsoft Academic Search

\\u000a Abstract\\u000a \\u000a \\u000a Background\\u000a   Attention-deficit\\/hyperactivity disorder (ADHD) in children affects every member of the family. Practical tools are needed\\u000a to assess the effects of ADHD on families to better understand and address the level of stress, strain and burden that families\\u000a experience.\\u000a \\u000a \\u000a \\u000a \\u000a Objective\\u000a   To provide the preliminary reliability, validity and factor structure of the Family Strain Index (FSI), a 6-item parent-report\\u000a questionnaire.

Anne W. Riley; Lisa M. Lyman; Georg Spiel; Manfred Döpfner; Maria J. Lorenzo

2006-01-01

147

Structural Equation Modeling for Analyzing Erythrocyte Fatty Acids in Framingham  

PubMed Central

Research has shown that several types of erythrocyte fatty acids (i.e., omega-3, omega-6, and trans) are associated with risk for cardiovascular diseases. However, there are complex metabolic and dietary relations among fatty acids, which induce correlations that are typically ignored when using them as risk predictors. A latent variable approach could summarize these complex relations into a few latent variable scores for use in statistical models. Twenty-two red blood cell (RBC) fatty acids were measured in Framingham (N = 3196). The correlation matrix of the fatty acids was modeled using structural equation modeling; the model was tested for goodness-of-fit and gender invariance. Thirteen fatty acids were summarized by three latent variables, and gender invariance was rejected so separate models were developed for men and women. A score was developed for the polyunsaturated fatty acid (PUFA) latent variable, which explained about 30% of the variance in the data. The PUFA score included loadings in opposing directions among three omega-3 and three omega-6 fatty acids, and incorporated the biosynthetic and dietary relations among them. Whether the PUFA factor score can improve the performance of risk prediction in cardiovascular diseases remains to be tested. PMID:24959197

Pottala, James V.; Djira, Gemechis D.; Espeland, Mark A.; Larson, Martin G.; Harris, William S.

2014-01-01

148

Evaluation of model fit in nonlinear multilevel structural equation modeling  

PubMed Central

Evaluating model fit in nonlinear multilevel structural equation models (MSEM) presents a challenge as no adequate test statistic is available. Nevertheless, using a product indicator approach a likelihood ratio test for linear models is provided which may also be useful for nonlinear MSEM. The main problem with nonlinear models is that product variables are non-normally distributed. Although robust test statistics have been developed for linear SEM to ensure valid results under the condition of non-normality, they have not yet been investigated for nonlinear MSEM. In a Monte Carlo study, the performance of the robust likelihood ratio test was investigated for models with single-level latent interaction effects using the unconstrained product indicator approach. As overall model fit evaluation has a potential limitation in detecting the lack of fit at a single level even for linear models, level-specific model fit evaluation was also investigated using partially saturated models. Four population models were considered: a model with interaction effects at both levels, an interaction effect at the within-group level, an interaction effect at the between-group level, and a model with no interaction effects at both levels. For these models the number of groups, predictor correlation, and model misspecification was varied. The results indicate that the robust test statistic performed sufficiently well. Advantages of level-specific model fit evaluation for the detection of model misfit are demonstrated. PMID:24624110

Schermelleh-Engel, Karin; Kerwer, Martin; Klein, Andreas G.

2013-01-01

149

Structural equation modeling of pesticide poisoning, depression, safety, and injury.  

PubMed

The role of pesticide poisoning in risk of injuries may operate through a link between pesticide-induced depressive symptoms and reduced engagement in safety behaviors. The authors conducted structural equation modeling of cross-sectional data to examine the pattern of associations between pesticide poisoning, depressive symptoms, safety knowledge, safety behaviors, and injury. Interviews of 1637 Colorado farm operators and their spouses from 964 farms were conducted during 1993-1997. Pesticide poisoning was assessed based on a history of ever having been poisoned. The Center for Epidemiologic Studies-Depression scale was used to assess depressive symptoms. Safety knowledge and safety behaviors were assessed using ten items for each latent variable. Outcomes were safety behaviors and injuries. A total of 154 injuries occurred among 1604 individuals with complete data. Pesticide poisoning, financial problems, health, and age predicted negative affect/somatic depressive symptoms with similar effect sizes; sex did not. Depression was more strongly associated with safety behavior than was safety knowledge. Two safety behaviors were significantly associated with an increased risk of injury. This study emphasizes the importance of financial problems and health on depression, and provides further evidence for the link between neurological effects of past pesticide poisoning on risk-taking behaviors and injury. PMID:24125049

Beseler, Cheryl L; Stallones, Lorann

2013-01-01

150

Applications of Multilevel Structural Equation Modeling to Cross-Cultural Research  

ERIC Educational Resources Information Center

Multilevel structural equation modeling (MSEM) has been proposed as an extension to structural equation modeling for analyzing data with nested structure. We have begun to see a few applications in cross-cultural research in which MSEM fits well as the statistical model. However, given that cross-cultural studies can only afford collecting data…

Cheung, Mike W.-L.; Au, Kevin

2005-01-01

151

Brooding and Pondering: Isolating the active ingredients of depressive rumination with exploratory factor analysis and structural equation modeling  

PubMed Central

Depressive rumination, as assessed by Nolen-Hoeksema’s Response Styles Questionnaire (RSQ; Nolen-Hoeksema & Morrow, 1991), 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, Treynor et al. (2003) identified two factors within the remaining RSQ rumination subscale that were differentially related to depression: brooding and pondering. However, Treynor et al. (2003) used a non-standard form and administration of the RSQ. The present study sought to address these methodological idiosyncrasies and replicate the factor structure of Treynor et al. (2003) through exploratory factor analysis and structural equation modeling. Findings support the brooding and pondering solution and demonstrate that brooding relates more strongly to depression and anxiety than does pondering. PMID:19667138

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

2010-01-01

152

Hard ellipses: Equation of state, structure, and self-diffusion.  

PubMed

Despite their fundamental and practical interest, the physical properties of hard ellipses remain largely unknown. In this paper, we present an event-driven molecular dynamics study for hard ellipses and assess the effects of aspect ratio and area fraction on their physical properties. For state points in the plane of aspect ratio (1 ? k ? 9) and area fraction (0.01 ? ? ? 0.8), we identify three different phases, including isotropic, plastic, and nematic states. We analyze in detail the thermodynamic, structural, and self-diffusive properties in the formed various phases of hard ellipses. The equation of state (EOS) is shown for a wide range of aspect ratios and is compared with the scaled particle theory (SPT) for the isotropic states. We find that SPT provides a good description of the EOS for the isotropic phase of hard ellipses. At large fixed ?, the reduced pressure p increases with k in both the isotropic and the plastic phases and, interestingly, its dependence on k is rather weak in the nematic phase. We rationalize the thermodynamics of hard ellipses in terms of particle motions. The static structures of hard ellipses are then investigated both positionally and orientationally in the different phases. The plastic crystal is shown to form for aspect ratios up to k = 1.4, while appearance of the stable nematic phase starts approximately at k = 3. We quantitatively determine the locations of the isotropic-plastic (I-P) transition and the isotropic-nematic (I-N) transition by analyzing the bond-orientation correlations and the angular correlations, respectively. As expected, the I-P transition point is found to increase with k, while a larger k leads to a smaller area fraction where the I-N transition takes place. Moreover, our simulations strongly support that the two-dimensional nematic phase in hard ellipses has only quasi-long-range orientational order. The self-diffusion of hard ellipses is further explored and connections are revealed between the structure and the self-diffusion. We discuss the relevance of our results to the glass transition in hard ellipses. Finally, the results of the isodiffusivity lines are evaluated for hard ellipses and we discuss the effect of spatial dimension on the diffusive dynamics of hard ellipsoidal particles. PMID:23862947

Xu, Wen-Sheng; Li, Yan-Wei; Sun, Zhao-Yan; An, Li-Jia

2013-07-14

153

Investigation on barriers to pharmaceutical care in community pharmacies: a structural equation model.  

PubMed

Objective The concept of pharmaceutical care (PhC) has been popular in pharmacy during past decades. However, in some countries, including Iran, it does not seem to mature. Aim of the study To identify and prioritize barriers to the provision of PhC in Iranian community pharmacies, based on the perceptions of community pharmacists in Tehran. Method Between August and November 2013, a cross-sectional descriptive study was performed using an anonymous questionnaire asking the pharmacists' perceptions on the implementation of PhC. Of the 2000 invited community pharmacists, 505 pharmacists responded. A descriptive analysis, was conducted, and the data were also analyzed through structural equation modeling. Main outcome measure Priorities of barriers to the implementation of PhC in Iran. Results Five major dimensions included in the survey instrument were confirmed by confirmatory factor analysis. According to the model developed based on pharmacists' opinions, lack of pharmacists' skills and lack of appropriate regulation and environment are the two most important barriers of the provision of PhC, and the least important is lack of resources. Conclusion The results show that the main barriers to PhC in Iran are the lack of skills and of appropriate regulation and environment. These main barriers are different from those mentioned in studies conducted in other countries. PMID:25168648

Mehralian, Gholamhossein; Rangchian, Maryam; Javadi, Athar; Peiravian, Farzad

2014-10-01

154

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

155

Modelling Functional Integration: A Comparison of Structural Equation and Dynamic Causal  

E-print Network

Modelling Functional Integration: A Comparison of Structural Equation and Dynamic Causal Models W of functional organisation, func- tional integration and functional specialisation, where the integration within approaches to modelling effective connectivity from fMRI data, Structural Equation Models (SEMs) and Dynamic

Gabrieli, John

156

A Bayesian Approach for Analyzing Hierarchical Data with Missing Outcomes through Structural Equation Models  

ERIC Educational Resources Information Center

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…

Song, Xin-Yuan; Lee, Sik-Yum

2008-01-01

157

Static and dynamic analyses of tensegrity structures. Part 1. Nonlinear equations of motion  

Microsoft Academic Search

In order to present basic equations for static and dynamic analyses of a class of truss structures called tensegrity structures, large-deformation kinematics and kinetics were presented in both Eulerian and Lagrangian formulations. The two sets of equations of motion yield the same values even if different stress and strain measures were employed for their computation. The Eulerian formulation was implemented

Hidenori Murakami

2001-01-01

158

Meta-Analytic Structural Equation Modeling (MASEM): Comparison of the Multivariate Methods  

ERIC Educational Resources Information Center

Meta-analytic Structural Equation Modeling (MASEM) has drawn interest from many researchers recently. In doing MASEM, researchers usually first synthesize correlation matrices across studies using meta-analysis techniques and then analyze the pooled correlation matrix using structural equation modeling techniques. Several multivariate methods of…

Zhang, Ying

2011-01-01

159

A Maximum Likelihood Approach for Multisample Nonlinear Structural Equation Models with Missing Continuous and Dichotomous Data  

ERIC Educational Resources Information Center

Structural equation models are widely appreciated in social-psychological research and other behavioral research to model relations between latent constructs and manifest variables and to control for measurement error. Most applications of SEMs are based on fully observed continuous normal data and models with a linear structural equation

Song, Xin-Yuan; Lee, Sik-Yum

2006-01-01

160

Maximum Likelihood Analysis of Nonlinear Structural Equation Models with Dichotomous Variables  

ERIC Educational Resources Information Center

In this article, a maximum likelihood approach is developed to analyze structural equation models with dichotomous variables that are common in behavioral, psychological and social research. To assess nonlinear causal effects among the latent variables, the structural equation in the model is defined by a nonlinear function. The basic idea of the…

Song, Xin-Yuan; Lee, Sik-Yum

2005-01-01

161

Sensitivity analysis of Lyapunov and Riccati equations with application to controls-structures integrated design  

NASA Technical Reports Server (NTRS)

Controls-structure integrated design is a complicated multidisciplinary design optimization problem which involves the state equations pertaining to open-loop eigenvalues and control laws. In order to alleviate the intensity of the computation, this study uses the adjoint variable method to derive sensitivity equations for the eigenvalue, Liapunov, and Riccati equations. These individual sensitivity equations are then combined together to form the multidisciplinary sensitivity equations for the control structure integrated design problems. A set of linear sensitivity equations, proportional in number to the number of performance functions involved in the optimization process, are solved. This proposed approach may provide a great saving in computer resources. The validity of the newly developed sensitivity equations is verified by numerical examples.

Hou, Gene; Koganti, Gopichand

1993-01-01

162

Factor structure of the Social Experience Questionnaire across time, sex, and grade among early elementary school children.  

PubMed

Ample research suggests that peer victimization predicts social and psychological maladjustment, including emotional (e.g., anxiety, low self-esteem, and depression) and behavioral (e.g., aggression) problems among children. Thus, a reliable measure of peer victimization for research with young children is needed. The Social Experience Questionnaire-Self-Report (SEQ-S) has been widely used in existing research to assess children's victimization (Crick & Grotpeter, 1996). However, empirical support for the psychometric properties of the SEQ-S is limited by the methods used to evaluate it (i.e., exploratory as opposed to confirmatory analyses), by the lack of longitudinal data, and by the limited age ranges studied. This study examined the underlying factor structure of SEQ-S ratings across 3 time points in a sample of 830 early elementary school children using confirmatory factor analysis. The hypothesized model included 3 latent factors: overt victimization, relational victimization, and receipt of prosocial acts from peers. This model provided a good fit to the data at each time point. Although it is not clear that there is invariance, results indicate that invariance across time, sex, and grade could be present. Recommendations for continued use of the SEQ-S in future research on peer victimization with young children are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved). PMID:23730827

Desjardins, Tracy; Yeung Thompson, Rachel S; Sukhawathanakul, Paweena; Leadbeater, Bonnie J; Macdonald, Stuart W S

2013-12-01

163

Mathematical Structure of Tetrad Equations for Vacuum Relativity  

E-print Network

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.

Frank B. Estabrook

2004-11-05

164

General Non-Markovian structure of Gaussian Master and Stochastic Schrödinger Equations  

E-print Network

General open quantum systems display memory features, their master equations are non-Markovian. We show that the subclass of Gaussian non-Markovian open system dynamics is tractable in a depth similar to the Markovian class. The structure of master equations exhibits a transparent generalization of the Lindblad structure. We find and parametrize the class of stochastic Schr\\"odinger equations that unravel a given master equation, such class was before known for Markovian systems only. We show that particular non-Markovian unravellings known in the literature are special cases of our class.

Lajos Diósi; Luca Ferialdi

2014-08-06

165

Discrete integration of continuous Kalman filtering equations for time invariant second-order structural systems  

NASA Technical Reports Server (NTRS)

A general form for the first-order representation of the continuous second-order linear structural-dynamics equations is introduced to derive a corresponding form of first-order continuous Kalman filtering equations. Time integration of the resulting equations is carried out via a set of linear multistep integration formulas. It is shown that a judicious combined selection of computational paths and the undetermined matrices introduced in the general form of the first-order linear structural systems leads to a class of second-order discrete Kalman filtering equations involving only symmetric sparse N x N solution matrices.

Park, K. C.; Belvin, W. Keith

1990-01-01

166

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

167

Fit Index Sensitivity in Multilevel Structural Equation Modeling  

E-print Network

to apply and their approach is not yet supported by generally available software. Conversely, the Muthén & Asparouhov (2008) approach is currently implemented in the SEM program Mplus (Muthén & Muthén, 1998-2010), and Rabe-Hesketh et al.’s (2004) method... ? (16) which implies ( ) ?= +? ? ??? ? (17) ( ) = +µ ? ? ?? (18) Equations 17 and 18 represent the standard CFA model-implied covariance matrix and mean vector (Brown, 2006). 20 In Mplus, the general MSEM model described...

Boulton, Aaron Jacob

2011-07-29

168

Structure of completely positive quantum master equations with memory kernel  

Microsoft Academic Search

Semi-Markov processes represent a well-known and widely used class of random processes in classical probability theory. Here, we develop an extension of this type of non-Markovian dynamics to the quantum regime. This extension is demonstrated to yield quantum master equations with memory kernels which allow the formulation of explicit conditions for the complete positivity of the corresponding quantum dynamical maps,

Heinz-Peter Breuer; Bassano Vacchini

2009-01-01

169

The Strengths and Difficulties Questionnaire in the Bergen Child Study: A Conceptually and Methodically Motivated Structural Analysis  

ERIC Educational Resources Information Center

Objective: To test Goodman's theoretical 5-factor model of the Strengths and Difficulties Questionnaire (SDQ) in an analysis of the Norwegian parent (P) and teacher (T) versions of the questionnaire. Method: The T-SDQ was analyzed for 8,999 (95.4% of all) children in primary school grades 2-4 in Bergen, Norway, whereas the P-SDQ was examined for…

Sanne, Bjarte; Torsheim, Torbjorn; Heiervang, Einar; Stormark, Kjell Morten

2009-01-01

170

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

171

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

172

Variational approach to the Hamiltonian structure of a new hierarchy of nonlinear equations  

SciTech Connect

We determine the symplectic Hamiltonian structure associated with the nonlinear evolution equations obtained from two new isospectral problems. We follow the method of variation with respect to the field variables. An explicit example is given to demonstrate the new class of equations that are generated.

Chowdbury, A.R.; Roy, S.

1986-02-01

173

A DIFFERENTIAL RICCATI EQUATION FOR THE ACTIVE CONTROL OF A PROBLEM IN STRUCTURAL ACOUSTICS  

E-print Network

A DIFFERENTIAL RICCATI EQUATION FOR THE ACTIVE CONTROL OF A PROBLEM IN STRUCTURAL ACOUSTICS GEORGE through a suitable Riccati Equation. This is achieved, in part, by exploiting recent techniques in the area of optimization of analytic systems with unbounded inputs, along with a local microanalysis

174

Generalized Moyal structures in phase-space, master equations and their classical limit  

Microsoft Academic Search

Generalized Wigner and Weyl transformations of quantum operators are defined and their properties, as well as those of the algebraic structure induced on phase-space, are reviewed. Using such transformations, quantum linear evolution equations are given a phase-space representation; particularly, the general master equation of the Lindblad type generating quantum dynamical semigroups. The resulting expressions are better suited for deriving quantum

Constantinos Tzanakis; Alkis P. Grecos

1998-01-01

175

Cognitive indicators of social anxiety in youth: a structural equation analysis.  

PubMed

Previous studies have demonstrated significant relationships among various cognitive variables such as negative cognition, self-efficacy, and social anxiety. Unfortunately, few studies focus on the role of cognition among youth, and researchers often fail to use domain-specific measures when examining cognitive variables. Therefore, the purpose of the present study was to examine domain-specific cognitive variables (i.e., socially oriented negative self-referent cognition and social self-efficacy) and their relationships to social anxiety in children and adolescents using structural equation modeling techniques. A community sample of children and adolescents (n=245; 55.9% female; 83.3% Caucasian, 9.4% African American, 2% Asian, 2% Hispanic, 2% "other," and 1.2% not reported) completed questionnaires assessing social cognition and social anxiety symptomology. Three latent variables were created to examine the constructs of socially oriented negative self-referent cognition (as measured by the SONAS scale), social self-efficacy (as measured by the SEQSS-C), and social anxiety (as measured by the SPAI-C and the Brief SA). The resulting measurement model of latent variables fit the data well. Additionally, consistent with the study hypothesis, results indicated that social self-efficacy likely mediates the relationship between socially oriented negative self-referent cognition and social anxiety, and socially oriented negative self-referent cognition yields significant direct and indirect effects on social anxiety. These findings indicate that socially oriented negative cognitions are associated with youth's beliefs about social abilities and the experience of social anxiety. Future directions for research and study limitations, including use of cross-sectional data, are discussed. PMID:24411119

Rudy, Brittany M; Davis, Thompson E; Matthews, Russell A

2014-01-01

176

Hilbert Space Structures on the Solution Space of Klein-Gordon Type Evolution Equations  

E-print Network

We use the theory of pseudo-Hermitian operators to address the problem of the construction and classification of positive-definite invariant inner-products on the space of solutions of a Klein-Gordon type evolution equation. This involves dealing with the peculiarities of formulating a unitary quantum dynamics in a Hilbert space with a time-dependent inner product. We apply our general results to obtain possible Hilbert space structures on the solution space of the equation of motion for a classical simple harmonic oscillator, a free Klein-Gordon equation, and the Wheeler-DeWitt equation for the FRW-massive-real-scalar-field models.

Ali Mostafazadeh

2002-09-06

177

Approximate Confidence Interval for Difference of Fit in Structural Equation Models.  

ERIC Educational Resources Information Center

Discusses a method, based on bootstrap methodology, for obtaining an approximate confidence interval for the difference in root mean square error of approximation of two structural equation models. Illustrates the method using a numerical example. (SLD)

Raykov, Tenko

2001-01-01

178

Further Insights on the French WISC–IV Factor Structure Through Bayesian Structural Equation Modeling  

E-print Network

The interpretation of the Wechsler Intelligence Scale for Children—Fourth Edition (WISC–IV) is based on a 4-factor model, which is only partially compatible with the mainstream Cattell–Horn–Carroll (CHC) model of intelligence measurement. The structure of cognitive batteries is frequently analyzed via exploratory factor analysis and/or confirmatory factor analysis. With classical confirmatory factor analysis, almost all crossloadings between latent variables and measures are fixed to zero in order to allow the model to be identified. However, inappropriate zero cross-loadings can contribute to poor model fit, distorted factors, and biased factor correlations; most important, they do not necessarily faithfully reflect theory. To deal with these methodological and theoretical limitations, we used a new statistical approach, Bayesian structural equation modeling (BSEM), among a sample of 249 French-speaking Swiss children (8–12 years). With BSEM, zero-fixed cross-loadings between latent variables and measures are replaced by approximate zeros, based on informative, small-variance priors. Results indicated that a direct hierarchical CHC-based model with 5 factors plus a general intelligence factor better represented the structure of the WISC–IV than did the 4-factor structure and the higher order models. Because a direct hierarchical CHC model was more adequate, it was

Isabelle Reverte; Jérôme Rossier; Nicolas Favez; Thierry Lecerf; Jérôme Rossier; Isabelle Reverte; Nicolas Favez; Thierry Lecerf

179

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

180

On the structure of nonlinear constitutive equations for fiber reinforced composites  

NASA Technical Reports Server (NTRS)

The structure of constitutive equations for nonlinear multiaxial behavior of transversely isotropic fiber reinforced metal matrix composites subject to proportional loading was investigated. Results from an experimental program were combined with numerical simulations of the composite behavior for complex stress to reveal the full structure of the equations. It was found that the nonlinear response can be described by a quadratic flow-potential, based on the polynomial stress invariants, together with a hardening rule that is dominated by two different hardening mechanisms.

Jansson, Stefan

1992-01-01

181

A homotopy algorithm for synthesizing robust controllers for flexible structures via the maximum entropy design equations  

NASA Technical Reports Server (NTRS)

One well known deficiency of LQG compensators is that they do not guarantee any measure of robustness. This deficiency is especially highlighted when considering control design for complex systems such as flexible structures. There has thus been a need to generalize LQG theory to incorporate robustness constraints. Here we describe the maximum entropy approach to robust control design for flexible structures, a generalization of LQG theory, pioneered by Hyland, which has proved useful in practice. The design equations consist of a set of coupled Riccati and Lyapunov equations. A homotopy algorithm that is used to solve these design equations is presented.

Collins, Emmanuel G., Jr.; Richter, Stephen

1990-01-01

182

Generalized pulse equations for through-transmission evaluation of arbitrary multilayered structures  

NASA Technical Reports Server (NTRS)

Generalized transit time and pulse amplitude equations were derived for modelling the ultrasonic through-transmission wave propagation of an arbitrary n-layered structure. The equations can be programmed into an expert system and used to identify and predict the through-transmission pulse signals from the critical interfaces of a multilayered structure. To test the formulas, the through transmission was measured from one- and three-layered configurations in the laboratory. The experimental measurements were compared with computer-generated data determined using the derived equations. The results verify the validity of the formulas.

Chern, E. James; Nielsen, Hatsumi T. C.

1990-01-01

183

Factor Structure of the Schalock and Keith Quality of Life Questionnaire (QOL-Q): Validation on Mexican and Spanish Samples  

ERIC Educational Resources Information Center

Background: The Quality of Life Questionnaire (QOL-Q) is used widely to evaluate the quality of life of persons with intellectual disability (ID). Its validity for use with Spanish-speaking cultures has been demonstrated for individuals with visual disabilities, but not for those with physical or intellectual disabilities. Such was the purpose of…

Caballo, C.; Crespo, M.; Jenaro, C.; Verdugo, M. A.; Martinez, J. L.

2005-01-01

184

Factor Structure of the Non-Cognitive Questionnaire-Revised Across Samples of Black and White College Students  

Microsoft Academic Search

The predictive validity of the Non-Cognitive Questionnaire (Tracey and Sedlacek, 1984) has been demonstrated in past research; however, some of the scales of this instrument have been found to have relatively low reliabilities. In an effort to improve measurement, the NCQ was revised and the reliability and validity examined on black and white samples of college entrants. First, the fit

Terence J. Tracey; William E. Sedlacek

1989-01-01

185

National Survey of Sensory Features in Children with ASD: Factor Structure of the Sensory Experience Questionnaire (3.0)  

ERIC Educational Resources Information Center

This national online survey study characterized sensory features in 1,307 children with autism spectrum disorder (ASD) ages 2-12 years using the Sensory Experiences Questionnaire Version 3.0 (SEQ-3.0). Using the SEQ-3.0, a confirmatory factor analytic model with four substantive factors of hypothesized sensory response patterns (i.e.,…

Ausderau, Karla; Sideris, John; Furlong, Melissa; Little, Lauren M.; Bulluck, John; Baranek, Grace T.

2014-01-01

186

Evaluating the Structure of the Mathematics Teacher Questionnaire: A Measure of Exposure to Mathematics Instructional Practices and Content  

ERIC Educational Resources Information Center

Psychometric properties of 24 items from the fifth grade Early Childhood Longitudinal Study-Kindergarten Cohort Mathematics Teacher Questionnaire were investigated in a sample of 5,181 participants. These items asked teachers to report how often they had their classroom students engage in different mathematics content, skills and instructional…

Ottmar, Erin R.; Konold, Timothy R.; Berry, Robert Q.; Grissmer, David W.; Cameron, Claire E.

2014-01-01

187

Anxiety, Depression and Hopelessness in Adolescents: A Structural Equation Model  

Microsoft Academic Search

Objective: This study tested a structural model, examining the relationship between a latent variable termed demoralization and measured variables (anxiety, depression and hopelessness) in a community sample of Canadian youth. Methods: The combined sample consisted of data collected from four independent studies from 2001 to 2005. Nine hundred and seventy one (n=971) participants were high school students (grades 10-12) from

Shaylyn Cunningham; Thelma Gunn; Assen Alladin; David Cawthorpe

2006-01-01

188

The feeding practices and structure questionnaire: construction and initial validation in a sample of Australian first-time mothers and their 2-year olds  

PubMed Central

Background Early feeding practices lay the foundation for children’s eating habits and weight gain. Questionnaires are available to assess parental feeding but overlapping and inconsistent items, subscales and terminology limit conceptual clarity and between study comparisons. Our aim was to consolidate a range of existing items into a parsimonious and conceptually robust questionnaire for assessing feeding practices with very young children (<3 years). Methods Data were from 462 mothers and children (age 21–27 months) from the NOURISH trial. Items from five questionnaires and two study-specific items were submitted to a priori item selection, allocation and verification, before theoretically-derived factors were tested using Confirmatory Factor Analysis. Construct validity of the new factors was examined by correlating these with child eating behaviours and weight. Results Following expert review 10 factors were specified. Of these, 9 factors (40 items) showed acceptable model fit and internal reliability (Cronbach’s ?: 0.61-0.89). Four factors reflected non-responsive feeding practices: ‘Distrust in Appetite’, ‘Reward for Behaviour’, ‘Reward for Eating’, and ‘Persuasive Feeding’. Five factors reflected structure of the meal environment and limits: ‘Structured Meal Setting’, ‘Structured Meal Timing’, ‘Family Meal Setting’, ‘Overt Restriction’ and ‘Covert Restriction’. Feeding practices generally showed the expected pattern of associations with child eating behaviours but none with weight. Conclusion The Feeding Practices and Structure Questionnaire (FPSQ) provides a new reliable and valid measure of parental feeding practices, specifically maternal responsiveness to children’s hunger/satiety signals facilitated by routine and structure in feeding. Further validation in more diverse samples is required. PMID:24898364

2014-01-01

189

Structural equation model of factors related to quality of life for community-dwelling schizophrenic patients in Japan  

PubMed Central

Background This study aimed to clarify how community mental healthcare systems can be improved. Methods We included 79 schizophrenic patients, aged 20 to 80 years, residing in the Tokyo metropolitan area who regularly visited rehabilitation facilities offering assistance to psychiatric patients and were receiving treatment on an outpatient basis. No subjects had severe cognitive disorders or were taking medication with side effects that could prevent the completion of questionnaires. Questionnaires included items related to quality of life, self-efficacy, self-esteem, psychosis based on the Behavior and Symptom Identification Scale, health locus of control, and socio-demographic factors. We performed multiple linear regression analysis with quality of life as the dependent variable and, based on covariance structural analysis, evaluated the goodness of fit of the resulting structural equations models. Results Self-efficacy, self-esteem, and degree of psychosis significantly impacted quality of life. Marital status, age, and types of medications also influenced quality of life. Multiple linear regression analysis revealed psychiatric symptoms (Behavior and Symptom Identification Scale-32 [daily living and role functioning] (Beta?=??0.537, p?structural analysis, the resulting model was found to exhibit reasonable goodness of fit. Conclusions Self-efficacy had an especially strong and direct impact on QOL. Therefore, it is important to provide more positive feedback to patients, provide social skills training based on cognitive behavioral therapy, and engage patients in role playing to improve self-efficacy and self-concept. PMID:25101143

2014-01-01

190

Does the level of expressed emotion (LEE) questionnaire have the same factor structure for adolescents as it has for adults?  

Microsoft Academic Search

Background  The level of expressed emotion (LEE) is a four-factor questionnaire that measures expressed emotion (EE) as perceived by the\\u000a recipient. These factors are: perceived lack of emotional support, perceived intrusiveness, perceived irritation, and perceive\\u000a criticism. The four factors of the LEE has previously been found to be related to psychological disorders and has good psychometric\\u000a properties for adults. However, it

William W. Hale; Quinten A. W. Raaijmakers; Coby Gerlsma; Wim Meeus

2007-01-01

191

Tests of Factor Structure and Measurement Invariance in the United States and Australia Using the Adult Version of the Parental Acceptance-Rejection Questionnaire  

Microsoft Academic Search

This study uses confirmatory factor analysis procedures to examine the factor structure of the mother and father versions of the Parental Acceptance-Rejection Questionnaire (PARQ) and their measurement invariance across ratings provided by 314 Australian adults and 509 adults in the United States. The adult version of the PARQ is a 60-item self-report instrument designed to measure adults’ perceptions of maternal

Rapson Gomez; Ronald P. Rohner

2011-01-01

192

Factor structure of the General Health Questionnaire (GHQ12) in subjects who had suffered from the 2004 Niigata-Chuetsu Earthquake in Japan: a community-based study  

Microsoft Academic Search

BACKGROUND: Factor structure of the 12-item General Health Questionnaire (GHQ-12) was studied by a survey of subjects who had experienced the 2004 Niigata-Chuetsu earthquake (6.8 on the Richter scale) in Japan. METHODS: Psychological distress was measured at two years after the earthquake by using GHQ-12 in 2,107 subjects (99.0% response rate) who suffered the earthquake. GHQ-12 was scored by binary,

Shin-ichi Toyabe; Toshiki Shioiri; Kuriko Kobayashi; Hideki Kuwabara; Masataka Koizumi; Taro Endo; Miki Ito; Hiroko Honma; Noboru Fukushima; Toshiyuki Someya; Kouhei Akazawa

2007-01-01

193

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

194

Structural model updating using frequency response function and quasi-linear sensitivity equation  

NASA Astrophysics Data System (ADS)

A method is presented for structural mass and stiffness estimation including damping effects and using vibration data. It uses the frequency response function (FRF) and natural frequencies data for finite element model updating. The FRF data are compiled using the measured displacement, velocity or acceleration of the damaged structure. A least-square algorithm method with appropriate normalization is used for solving the over-determined system of equations with noise-polluted data. Sensitivity equation normalization and proper selection of measured frequency points improved the accuracy and convergence in finite element model updating. Using simulated measurements shows that this method can detect, locate and quantify the severity of damage within structures.

Esfandiari, A.; Bakhtiari-Nejad, F.; Rahai, A.; Sanayei, M.

2009-10-01

195

Structure-function hierarchies and von Kármán-Howarth relations for turbulence in magnetohydrodynamical equations.  

PubMed

We generalize the method of A. M. Polyakov, [ Phys. Rev. E 52 6183 (1995)] for obtaining structure-function relations in turbulence in the stochastically forced Burgers equation, to develop structure-function hierarchies for turbulence in three models for magnetohydrodynamics (MHD). These are the Burgers analogs of MHD in one dimension [ Eur. Phys. J. B 9 725 (1999)], and in three dimensions (3DMHD and 3D Hall MHD). Our study provides a convenient and unified scheme for the development of structure-function hierarchies for turbulence in a variety of coupled hydrodynamical equations. For turbulence in the three sets of MHD equations mentioned above, we obtain exact relations for third-order structure functions and their derivatives; these expressions are the analogs of the von Kármán-Howarth relations for fluid turbulence. We compare our work with earlier studies of such relations in 3DMHD and 3D Hall MHD. PMID:24580182

Basu, Abhik; Naji, Ali; Pandit, Rahul

2014-01-01

196

Evaluation of Existing Structure and Civil Protection Management Framework in Greek Local Authorities: A Questionnaire Survey Demonstrates Why Prevention Fails  

NASA Astrophysics Data System (ADS)

In the face of a growing number of natural disasters and the increasing costs associated with them, Europe and Greece in particular, have devoted significant efforts and resources in natural hazards mitigation during the last decades. Despite the significant legislative efforts (e.g. 1998/22/EC, 2001/792/EC, 2007/60/EC Directives, 3013/2002 Act) and even though a number of steps has been taken towards improving civil protection, recent catastrophic events have illustrated the weaknesses of current approaches. In particular, in Greece, events such as the 1999 Athens earthquake, the 2007 and 2009 wildfires have shown the inadequacy of prevention and mitigation practices. Given the enhanced civil protection responsibilities, given by the Greek national law (Acts 3013/2002, 3852/2010) to local authorities in Greece, this work analyses and evaluates the existing structure and current management framework under which local authorities function and examines their risk mitigation practices. We conducted the largest questionnaire survey regarding Civil Protections issues, among the municipalities of Greece. To this aim, this work used a innovative online tool to assess current framework. Therefore, a network connecting civil protection departments of municipalities was developed, based on an Internet platform that acted also as a communication tool. Overall, we had feedback either online or offline from 125 municipalities across the country (representing more than one/third of the total municipalities of Greece). Through this network, municipal civil protection officials completed surveys designed to obtain and quantify information on several aspects of civil protection practices and infrastructure. In particular, the examined factors included: (i) personnel and equipment, (ii) inter-agency cooperation, (iii) training, (iv) compliance with existing regulations and (v) persistent problems encountered by civil protection departments, that prevent the effectiveness of current practices. Responses showed that civil protection personnel lack adequate training and expertise, many are overstretched with several duties, while several prevention actions are carried out by seasonal or voluntary staff. Approximately half of the heads of civil protection offices do not hold a university degree, only 27% have a relevant scientific background (geoscientists or engineers) and more than half of them are elected members and not permanent staff, implying that no continuity is secured. Inter-agency cooperation is shown to be poor and organizational learning from international practices not adequate. Half of the municipalities report that the authorization processes are too slow so that prevention actions particularly regarding forest fires are severely delayed. Existing regulations are not followed by a significant portion of municipalities since 19% have not established a civil protection office and 23% have not compiled an action plan yet. Existing action plans lack important information, present no spatial data and are predominantly catalogues and tables of information regarding authorised personnel and equipment. Overall, underfunding, poor coordination of the different actors involved, lack of training and understaffing, lack of proper equipment and several other issues are held responsible by officials for preventing effectiveness of current practices. Finally, the EU emergency number 112 is widely unknown (87%). This work was held under the LIFE+ project "Local Authorities Alliance for Forest Fire Prevention - LIFE08/ENV/GR/000553" which is implemented with the contribution of the LIFE financial instrument of the European Community.

Papanikolaou, Dimitrios; Papanikolaou, Ioannis; Diakakis, Michalis; Deligiannakis, Georgios

2013-04-01

197

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 modeling…

Bai, Yun; Poon, Wai-Yin

2009-01-01

198

Prediction of attitudes towards restrictive aids policies: A structural equation modelling approach  

Microsoft Academic Search

The purpose of the study was to test a prehypothesized structural equation model of predictors of attitudes towards restrictive AIDS policies. It was assumed that such attitudes are under influence of both cognitive processes and more general attitudinal structures. The hypothesized model was tested against empirical data from a nation-wide survey of Norwegian adults, including 543 males and 577 females.

Pål Kraft; Jostein Rise

1995-01-01

199

Introducing Algebraic Structures through Solving Equations: Vertical Content Knowledge for K-12 Mathematics Teachers  

ERIC Educational Resources Information Center

Algebraic structures are a necessary aspect of algebraic thinking for K-12 students and teachers. An approach for introducing the algebraic structure of groups and fields through the arithmetic properties required for solving simple equations is summarized; the collective (not individual) importance of these axioms as a foundation for algebraic…

Wasserman, Nicholas H.

2014-01-01

200

Analysis of frequency band structure in one-dimensional sonic crystal using Webster horn equation  

Microsoft Academic Search

Sound propagation through periodic arrangement of scatterers lead to formation of bands of frequencies, known as band gaps, where sound cannot propagate though the structure. We propose a method based on Webster horn equation, along with Floquet theorem, to predict the band gap of a one-dimensional periodic structure made of hard sound-scatterers. The method is further modified to obtain the

A. Gupta; K. M. Lim; C. H. Chew

2011-01-01

201

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

202

Questioning Newton's second law: What is the structure of equations of motion?  

Microsoft Academic Search

Interactions are explored through the observation of the dynamics of particles. On the classical level the basic underlying assumption in that scheme is that Newton's second law holds. Relaxing the validity of this axiom by, e.g., allowing for higher order time derivatives in the equations of motion would allow for a more general structure of interactions. We derive the structure

Claus Lämmerzahl; Patricia Rademaker

2009-01-01

203

The Effect of Perceived Instructional Effectiveness on Student Loyalty: A Multilevel Structural Equation Model  

ERIC Educational Resources Information Center

Social sciences research often entails the analysis of data with a multilevel structure. An example of multilevel data is containing measurement on university students nested within instructors. This paper concentrates on multilevel analysis of structural equation modeling with educational data. Data used in this study were gathered from 17647…

Simsek, Gulhayat Golbasi; Noyan, Fatma

2009-01-01

204

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

205

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

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

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

ERIC Educational Resources Information Center

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…

Lee, Sik-Yum; Song, Xin-Yuan

2005-01-01

208

Analysis of Structural Equation Model with Ignorable Missing Continuous and Polytomous Data.  

ERIC Educational Resources Information Center

Developed a Bayesian approach for structural equation models with ignorable missing continuous and polytomous data that obtains joint Bayesian estimates of thresholds, structural parameters, and latent factor scores simultaneously. Illustrated the approach through analysis of a real data set of 20 patterns of condom use in the Philippines. (SLD)

Song, Xin-Yuan; Lee, Sik-Yum

2002-01-01

209

A stiffness equation transfer method for transient dynamic response analysis of structures  

Microsoft Academic Search

A stiffness equation transfer method is proposed for transient dynamic response analysis of structures under various excitations. This method is a development and refinement of the combined finite element-transfer matrix (FE-TM) method. In the present method, the transfer of state vectors from left to right in the FE-TM method is changed into the transfer of general stiffness equations of every

Huiyu Xue

2004-01-01

210

Testing strong factorial invariance using three-level structural equation modeling  

PubMed Central

Within structural equation modeling, the most prevalent model to investigate measurement bias is the multigroup model. Equal factor loadings and intercepts across groups in a multigroup model represent strong factorial invariance (absence of measurement bias) across groups. Although this approach is possible in principle, it is hardly practical when the number of groups is large or when the group size is relatively small. Jak et al. (2013) showed how strong factorial invariance across large numbers of groups can be tested in a multilevel structural equation modeling framework, by treating group as a random instead of a fixed variable. In the present study, this model is extended for use with three-level data. The proposed method is illustrated with an investigation of strong factorial invariance across 156 school classes and 50 schools in a Dutch dyscalculia test, using three-level structural equation modeling. PMID:25120499

Jak, Suzanne

2014-01-01

211

First-principles prediction of the equation of state for TcC with rocksalt structure  

NASA Astrophysics Data System (ADS)

The equation of state of TcC with rocksalt structure is investigated by means of first-principles density functional theory calculations combined with the quasi-harmonic Debye model in which the phononic effects are considered. Particular attention is paid to the predictions of the compressibility, the isothermal bulk modulus and its first pressure derivative which play a central role in the formulation of approximate equations of state for the first time. The properties of TcC with rocksalt structure are summarized in the pressure range of 0-80 GPa and the temperature up to 2500 K.

Sun, Xiao-Wei; Chu, Yan-Dong; Liu, Zi-Jiang; Song, Ting; Tian, Jun-Hong; Wei, Xiao-Ping

2014-10-01

212

Online Social Presence: Score Validity of the Computer-Mediated Communication Questionnaire  

ERIC Educational Resources Information Center

The purpose of this study was to conduct a confirmatory factor analysis of the Computer-Mediated Communication Questionnaire scores, using structural equation modeling, to assess the consistency between the empirical data and the hypothesized factor structure of the CMCQ in the proposed models, which is stipulated by the theoretical framework and…

Yen, Cherng-Jyh

2008-01-01

213

The structure of hypersonic shock waves using Navier-Stokes equations modified to include mass diffusion  

E-print Network

Howard Brenner has recently proposed modifications to the Navier-Stokes equations that relate to a diffusion of fluid volume that would be significant for flows with high density gradients. In a previous paper (Greenshields & Reese, 2007), we found these modifications gave good predictions of the viscous structure of shock waves in argon in the range Mach 1.0-12.0 (while conventional Navier-Stokes equations are known to fail above about Mach 2). However, some areas of concern with this model were a somewhat arbitrary choice of modelling coefficient, and potentially unphysical and unstable solutions. In this paper, we therefore present slightly different modifications to include molecule mass diffusion fully in the Navier-Stokes equations. These modifications are shown to be stable and produce physical solutions to the shock problem of a quality broadly similar to those from the family of extended hydrodynamic models that includes the Burnett equations. The modifications primarily add a diffusion term to t...

Greenshields, Christopher J

2007-01-01

214

Questioning Newton's second law: What is the structure of equations of motion?  

E-print Network

Interactions are explored through the observation of the dynamics of particles. On the classical level the basic underlying assumption in that scheme is that Newton's second law holds. Relaxing the validity of this axiom by, e.g., allowing for higher order time derivatives in the equations of motion would allow for a more general structure of interactions. We derive the structure of interactions by means of a gauge principle and discuss the physics emerging from equations of motion of higher order. One main result is higher order derivatives induce a zitterbewegung. As a consequence the main motion resulting from the second order equation of motion is rather robust against modifications. The gauge principle leads to a gauge field with the property of a space metric. We confront this general scheme with experimental data.

Claus Lämmerzahl; Patricia Rademaker

2009-04-30

215

Structural Equation Modeling in Pediatric Psychology: Overview and Review of Applications  

Microsoft Academic Search

Objective To describe the use of structural equation modeling (SEM) in the Journal of Pediatric Psychology (JPP) and to discuss the usefulness of SEM applications in pediatric psychology research. Method The use of SEM in JPP between 1997 and 2006 was examined and compared to leading journals in clinical psychology, clinical child psychology, and child development. Results SEM techniques were

Timothy D. Nelson; Brandon S. Aylward; Ric G. Steele

2008-01-01

216

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

217

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

218

Numerical Simulation when Interest Rate Term Structure is Modelled as a Stochastic Partial Differential Equation  

Microsoft Academic Search

This paper presents a new approach for numerically simulating the yield curve for the term structure of a zero coupon bond in which the forward rate process is modelled as as tochastic partial differential equations (SPDEs). The numerical technique involves using the method of lines (MOL) to convert the SPDE into a system of SDEs. As stated in chapter four,

Stuart McDonald

2007-01-01

219

Testing Time-Invariance of Variable Specificity in Repeated Measure Designs Using Structural Equation Modeling  

ERIC Educational Resources Information Center

A structural equation modeling method for examining time-invariance of variable specificity in longitudinal studies with multiple measures is outlined, which is developed within a confirmatory factor-analytic framework. The approach represents a likelihood ratio test for the hypothesis of stability in the specificity part of the residual term…

Raykov, Tenko; Amemiya, Yasuo

2008-01-01

220

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

221

Vocabulary and Grammar Knowledge in Second Language Reading Comprehension: A Structural Equation Modeling Study  

ERIC Educational Resources Information Center

Using structural equation modeling analysis, this study examined the contribution of vocabulary and grammatical knowledge to second language reading comprehension among 190 advanced Chinese English as a foreign language learners. Vocabulary knowledge was measured in both breadth (Vocabulary Levels Test) and depth (Word Associates Test);…

Zhang, Dongbo

2012-01-01

222

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

223

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

224

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). Unlike…

Larwin, Karen; Harvey, Milton

2012-01-01

225

Stratified structure of the Universe and Burgers' equation—a probabilistic approach  

Microsoft Academic Search

Summary The model of the potential turbulence described by the 3-dimensional Burgers' equation with random initial data was developped by Zeldovich and Shandarin, in order to explain the existing Large Scale Structure of the Universe. Most of the recent probabilistic investigations of large time asymptotics of the solution deal with the central limit type results (the “Gaussian scenario”), under suitable

Sergio Albeverio; Stanislav A. Molchanov; Donatas Surgailis

1994-01-01

226

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

227

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

ERIC Educational Resources Information Center

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…

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

2007-01-01

228

Scholastic Achievement in High School Explained? Validation of a Longitudinal Structural Equations Model  

ERIC Educational Resources Information Center

The purpose of the study is to shed light on the mechanisms behind scholastic achievement in high school by testing a structural equations model based on the work by Vermunt (1998). It was presumed that self-regulation of learning would predict scholastic achievement and that learning orientations would predict self-regulation of learning. A…

Hellle, Laura; Tuijula, Tiina; Laakkonen, Eero

2009-01-01

229

A ballistic limit equation for hypervelocity impacts on CFRP Al H\\/C satellite structures  

Microsoft Academic Search

Composite sandwich panels consisting of Carbon Fiber Reinforced Plastic facesheets bonded to Aluminum honeycomb cores CFRP Al H C SP are amongst the most commonly used structures for satellites due to their relative low mass and high thermal and mechanical stability To assess the threat of micrometeoroid orbital debris M OD on a satellite mission equations which define the limits

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

2006-01-01

230

On the Madness in His Method: R. B. Cattell's Contributions to Structural Equation Modeling.  

ERIC Educational Resources Information Center

The many methodological contributions of Raymond B. Cattell to multivariate analysis are discussed in terms of contemporary issues in structural equation modeling. His factor analytic approach is compared with current modeling practices. A critical evaluation finds much of Cattell's work still innovative, technically advanced, and valuable to…

McArdle, J. Jack

1984-01-01

231

An Examination of Statistical Power in Multigroup Dynamic Structural Equation Models  

ERIC Educational Resources Information Center

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…

Prindle, John J.; McArdle, John J.

2012-01-01

232

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

233

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

ERIC Educational Resources Information Center

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…

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

2005-01-01

234

Rethinking fit assessment in structural equation modelling: A commentary and elaboration on Barrett (2007)  

Microsoft Academic Search

With seemingly few exceptions, current practice in structural equation modelling (SEM) aims at establishing close rather than exact fit between hypothetical models and observed data. This orientation has gone without serious challenge until the appearance of a sharp critique by Barrett (2007), who suggests discontinuing the use of approximate fit indices (AFIs) in SEM. The present article provides a commentary

Cameron N. McIntosh

2007-01-01

235

Sample Size Requirements for Structural Equation Models: An Evaluation of Power, Bias, and Solution Propriety  

ERIC Educational Resources Information Center

Determining sample size requirements for structural equation modeling (SEM) is a challenge often faced by investigators, peer reviewers, and grant writers. Recent years have seen a large increase in SEMs in the behavioral science literature, but consideration of sample size requirements for applied SEMs often relies on outdated rules-of-thumb.…

Wolf, Erika J.; Harrington, Kelly M.; Clark, Shaunna L.; Miller, Mark W.

2013-01-01

236

Using Structural Equation Modeling to Assess Functional Connectivity in the Brain: Power and Sample Size Considerations  

ERIC Educational Resources Information Center

The present study assessed the impact of sample size on the power and fit of structural equation modeling applied to functional brain connectivity hypotheses. The data consisted of time-constrained minimum norm estimates of regional brain activity during performance of a reading task obtained with magnetoencephalography. Power analysis was first…

Sideridis, Georgios; Simos, Panagiotis; Papanicolaou, Andrew; Fletcher, Jack

2014-01-01

237

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

238

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

239

A DIFFERENTIAL RICCATI EQUATION FOR THE ACTIVE CONTROL OF A PROBLEM IN STRUCTURAL ACOUSTICS  

E-print Network

A DIFFERENTIAL RICCATI EQUATION FOR THE ACTIVE CONTROL OF A PROBLEM IN STRUCTURAL ACOUSTICS GEORGE control theory or this class of problems and characterize the optimal control through a suitable Riccati of analytic systems with unbounded inputs, along with a local microanalysis of the hyperbolic part

240

Simultaneous Study of Individual and Group Patterns of Latent Longitudinal Change Using Structural Equation Modeling.  

ERIC Educational Resources Information Center

Structural equation modeling is used in the simultaneous study of individual and group latent change patterns on several longitudinally assessed variables. The approach, which is based on a special case of the comprehensive latent curve analysis of W. Meredith and J. Tisak (1990), is illustrated with a two-group study. (SLD)

Raykov, Tenko

1997-01-01

241

Comparison of Approaches to Constructing Confidence Intervals for Mediating Effects Using Structural Equation Models  

ERIC Educational Resources Information Center

Mediators are variables that explain the association between an independent variable and a dependent variable. Structural equation modeling (SEM) is widely used to test models with mediating effects. This article illustrates how to construct confidence intervals (CIs) of the mediating effects for a variety of models in SEM. Specifically, mediating…

Cheung, Mike W. L.

2007-01-01

242

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

243

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

244

Exploring Mediating Effect of Metacognitive Awareness on Comprehension of Science Texts through Structural Equation Modeling Analysis  

ERIC Educational Resources Information Center

This study used a Chinese-language version of the Index of Science Reading Awareness (ISRA) to investigate metacognitive awareness and the Reading Comprehension of Science Test (RCST) to explore comprehension of science text by Taiwanese students. Structural equation modeling (SEM) results confirmed the validity of the underlying models of…

Wang, Jing-Ru; Chen, Shin-Feng

2014-01-01

245

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

246

Perfectionism, Dysfunctional Attitudes, and Self-Esteem: A Structural Equations Analysis  

ERIC Educational Resources Information Center

The researchers in this study examined the association between adaptive and maladaptive dimensions of perfectionism and self-esteem. Confirmatory factor analysis and structural equations modeling were used to develop and test a model derived from theoretical links between perfectionism and self-esteem. Path models revealed that adaptive…

Ashby, Jeffrey S.; Rice, Kenneth G.

2002-01-01

247

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

248

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

249

A Polychoric Instrumental Variable (PIV) Estimator for Structural Equation Models with Categorical Variables  

ERIC Educational Resources Information Center

This paper presents a new polychoric instrumental variable (PIV) estimator to use in structural equation models (SEMs) with categorical observed variables. The PIV estimator is a generalization of Bollen's (Psychometrika 61:109-121, 1996) 2SLS/IV estimator for continuous variables to categorical endogenous variables. We derive the PIV estimator…

Bollen, Kenneth A.; Maydeu-Olivares, Albert

2007-01-01

250

What is the Structure of Equations of Motion? Testing Newton's Second Law  

Microsoft Academic Search

Interactions are explored through the observation of the dynamics of particles. On the classical level the basic underlying assumption in that scheme is that Newton's second law holds. Re-laxing the validity of this axiom by allowing for higher order time derivatives in the equations of motion, for example, would allow for a more general structure of interactions. We derive the

Claus Laemmerzahl

2010-01-01

251

Estimation of Generalizability Coefficients via a Structural Equation Modeling Approach to Scale Reliability Evaluation  

ERIC Educational Resources Information Center

A structural equation modeling approach to scale reliability evaluation can be employed to estimate generalizability theory indexes in settings where sampling of subjects and conditions is carried out. In one- and two-facet crossed designs, it is demonstrated how this method can be used to obtain estimates of relative generalizability…

Raykov, Tenko; Marcoulides, George A.

2006-01-01

252

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

ERIC Educational Resources Information Center

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…

Borja, Susan E.; Callahan, Jennifer L.

2009-01-01

253

Rumination and Distraction Among Chronic Depressives in Treatment: A Structural Equation Analysis  

Microsoft Academic Search

Response Styles Theory hypothesizes that rumination about one's symptoms amplifies and prolongs depressed mood, whereas distraction has the opposite effect. Response styles are also hypothesized to be trait-like dispositions. The generalizability of Response Styles Theory, as well as the linkages that may account for correlations between rumination, distraction, and depression, were explored with structural equation modeling in a sample of

Bruce A. Arnow; Diane Spangler; Daniel N. Klein; David D. Burns

2004-01-01

254

Using a Structural Equation Model to Describe the Infusion of Civic Engagement in the Campus Culture  

ERIC Educational Resources Information Center

This study assesses whether Tufts University's campus culture was successful at infusing civic-mindedness in all undergraduates. A structural equation model was developed, and findings revealed that the campus environment had a significant positive impact on civic values and beliefs and a positive indirect effect on civic engagement activities.…

Billings, Meredith S.; Terkla, Dawn Geronimo

2011-01-01

255

Cultural, Social, and Economic Capital Constructs in International Assessments: An Evaluation Using Exploratory Structural Equation Modeling  

ERIC Educational Resources Information Center

The article employs exploratory structural equation modeling (ESEM) to evaluate constructs of economic, cultural, and social capital in international large-scale assessment (LSA) data from the Progress in International Reading Literacy Study (PIRLS) 2006 and the Programme for International Student Assessment (PISA) 2009. ESEM integrates the…

Caro, Daniel H.; Sandoval-Hernández, Andrés; Lüdtke, Oliver

2014-01-01

256

A Brief Introduction to Structural Equation Modeling Techniques: Theory and Application.  

ERIC Educational Resources Information Center

This paper provides theoretical and practical information about using structural equation modeling (SEM) techniques. The first section discusses the theory of SEM, including five general steps: (1) model specification; (2) model identification; (3) model estimation; (4) testing model fit; and (5) model respecification. The second section applies…

Baloglu, Mustafa

257

Maximum Likelihood Estimation of Nonlinear Structural Equation Models with Ignorable Missing Data  

ERIC Educational Resources Information Center

The existing maximum likelihood theory and its computer software in structural equation modeling are established on the basis of linear relationships among latent variables with fully observed data. However, in social and behavioral sciences, nonlinear relationships among the latent variables are important for establishing more meaningful models…

Lee, Sik-Yum; Song, Xin-Yuan; Lee, John C. K.

2003-01-01

258

Bayesian Analysis of Nonlinear Structural Equation Models with Nonignorable Missing Data  

ERIC Educational Resources Information Center

A Bayesian approach is developed for analyzing nonlinear structural equation models with nonignorable missing data. The nonignorable missingness mechanism is specified by a logistic regression model. A hybrid algorithm that combines the Gibbs sampler and the Metropolis-Hastings algorithm is used to produce the joint Bayesian estimates of…

Lee, Sik-Yum

2006-01-01

259

Ambition, Self-Concept, and Achievement: A Structural Equation Model for Comparing Rural and Urban Students  

Microsoft Academic Search

The Western Australian School Effectiveness Study (WASES) provided this researcher with a unique opportunity to investigate the relationships betweenstudent aspirations, student self-concept, and student achievement. These relation­ ships were estimated using structural equation modelling. The hypothesis that rural and urban students may behave differently and have different influences was alsoinvestigated using a technique called multi-sample Analysis in the LISREL software

Deidra J. Young

1998-01-01

260

Using Structural Equation Models with Latent Variables to Study Student Growth and Development.  

ERIC Educational Resources Information Center

Analysis of data on freshman-to-senior developmental gains in 722 University of Tennessee-Knoxville students provides evidence of the advantages of structural equation modeling with latent variables and suggests that the group differences identified by traditional analysis of variance and covariance techniques may be an artifact of measurement…

Pike, Gary R.

1991-01-01

261

Using Mixed-Effects Structural Equation Models to Study Student Academic Development.  

ERIC Educational Resources Information Center

A study at the University of Tennessee Knoxville used mixed-effect structural equation models incorporating latent variables as an alternative to conventional methods of analyzing college students' (n=722) first-year-to-senior academic gains. Results indicate, contrary to previous analysis, that coursework and student characteristics interact to…

Pike, Gary R.

1992-01-01

262

Structural Equation Modeling in Language Testing and Learning Research: A Review  

ERIC Educational Resources Information Center

Despite the recent increase of structural equation modeling (SEM) in language testing and learning research and Kunnan's (1998) call for the proper use of SEM to produce useful findings, there seem to be no reviews about how SEM is applied in these areas or about the extent to which the current application accords with appropriate practices. To…

In'nami, Yo; Koizumi, Rie

2011-01-01

263

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

264

Estimating, Testing, and Comparing Specific Effects in Structural Equation Models: The Phantom Model Approach  

ERIC Educational Resources Information Center

The phantom model approach for estimating, testing, and comparing specific effects within structural equation models (SEMs) is presented. The rationale underlying this novel method consists in representing the specific effect to be assessed as a total effect within a separate latent variable model, the phantom model that is added to the main…

Macho, Siegfried; Ledermann, Thomas

2011-01-01

265

Reliability of Summed Item Scores Using Structural Equation Modeling: An Alternative to Coefficient Alpha  

ERIC Educational Resources Information Center

A method is presented for estimating reliability using structural equation modeling (SEM) that allows for nonlinearity between factors and item scores. Assuming the focus is on consistency of summed item scores, this method for estimating reliability is preferred to those based on linear SEM models and to the most commonly reported estimate of…

Green, Samuel B.; Yang, Yanyun

2009-01-01

266

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

ERIC Educational Resources Information Center

Longitudinal structural equation modeling (SEM) can be a basis for making prescriptive statements on educational practice and offers yields over "traditional" statistical techniques under the general linear model. The extent to which prescriptive statements can be made will rely on the appropriate accommodation of key elements of research design,…

Martin, Andrew J.

2011-01-01

267

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

268

Fixed-Effects Meta-Analyses as Multiple-Group Structural Equation Models  

ERIC Educational Resources Information Center

Meta-analysis is the statistical analysis of a collection of analysis results from individual studies, conducted for the purpose of integrating the findings. Structural equation modeling (SEM), on the other hand, is a multivariate technique for testing hypothetical models with latent and observed variables. This article shows that fixed-effects…

Cheung, Mike W. -L.

2010-01-01

269

A Two-Stage Approach to Synthesizing Covariance Matrices in Meta-Analytic Structural Equation Modeling  

ERIC Educational Resources Information Center

Structural equation modeling (SEM) is widely used as a statistical framework to test complex models in behavioral and social sciences. When the number of publications increases, there is a need to systematically synthesize them. Methodology of synthesizing findings in the context of SEM is known as meta-analytic SEM (MASEM). Although correlation…

Cheung, Mike W. L.; Chan, Wai

2009-01-01

270

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

271

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

272

Structural Equation Modelling of Multiple Facet Data: Extending Models for Multitrait-Multimethod Data  

ERIC Educational Resources Information Center

This paper is about the structural equation modelling of quantitative measures that are obtained from a multiple facet design. A facet is simply a set consisting of a finite number of elements. It is assumed that measures are obtained by combining each element of each facet. Methods and traits are two such facets, and a multitrait-multimethod…

Bechger, Timo M.; Maris, Gunter

2004-01-01

273

Improving the Root Mean Square Error of Approximation for Nonnormal Conditions in Structural Equation Modeling  

Microsoft Academic Search

In this study, the authors investigated incorporating adjusted model fit information into the root mean square error of approximation (RMSEA) fit index. Through Monte Carlo simulation, the usefulness of this adjusted index was evaluated for assessing model adequacy in structural equation modeling when the multivariate normality assumption underlying maximum likelihood estimation is violated. Adjustment to the RMSEA was considered in

Jonathan Nevitt; Gregory R. Hancock

2000-01-01

274

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 prejudice.…

Tebbe, Esther N.; Moradi, Bonnie

2012-01-01

275

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

276

The Issue of Isopower in Power Analysis for Tests of Structural Equation Models  

ERIC Educational Resources Information Center

Two general frameworks have been proposed for evaluating statistical power of tests of model fit in structural equation modeling (SEM). Under the Satorra-Saris (1985) approach, to evaluate the power of the test of fit of Model A, a Model B, within which A is nested, is specified as the alternative hypothesis and considered as the true model. We…

MacCallum, Robert; Lee, Taehun; Browne, Michael W.

2010-01-01

277

Testing Mediation Using Multiple Regression and Structural Equation Modeling Analyses in Secondary Data  

ERIC Educational Resources Information Center

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…

Li, Spencer D.

2011-01-01

278

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

279

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, consequently, acceptance in their domain. Interestingly, relatively little attention has been paid to assessing the use of partial least squares structural equation modeling (PLS-SEM) in marketing research?despite its increasing popularity in recent years. To fill this gap, we conducted an extensive search in the 30

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

2012-01-01

280

Hypothesis Testing and Model Comparison in Two-Level Structural Equation Models.  

ERIC Educational Resources Information Center

Demonstrates the use of the well-known Bayes factor in the Bayesian literature for hypothesis testing and model comparison in general two-level structural equation models. Shows that the proposed method is flexible and can be applied to situations with a wide variety of nonnested models. (SLD)

Lee, Sik-Yum; Song, Xin-Yuan

2001-01-01

281

Eight Myths About Causality and Structural Equation Kenneth A. Bollen and Judea Pearl  

E-print Network

Chapter 15 Eight Myths About Causality and Structural Equation Models Kenneth A. Bollen and Judea accumulated. A variety of misunderstandings and myths about the nature of SEMs and their role in causal by presenting eight myths about causality and SEMs in the hope that this will lead to a more accurate

California at Los Angeles, University of

282

Geometric structures on solutions of equations of 3-dimensional adiabatic gas motion  

NASA Astrophysics Data System (ADS)

In this paper, we show that characteristic covectors of a system of equations of 3-dimensional adiabatic gas motion generate a geometric structure on every solution of this system. This structure consists of a hyperplane and a non degenerate cone in every cotangent space to a solution. These hyperplane and cone intersect in zero point only. We construct differential invariants of this structure: a vector field, a conformal structure, a Lorentzian metric, and a linear connection. In the case of polytropic gas motion, we calculate classes of explicit solutions possessing the linear connection with zero torsion.

Yumaguzhin, Valeriy

2014-11-01

283

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

284

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

285

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

286

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 potential…

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

2007-01-01

287

Entropy conditions for quasilinear first order equations on nonlinear fiber bundles with special emphasis on the equation of 2D flat projective structure. I  

E-print Network

Taking only the characteristics as absolute, in the spirit of Arnold's "Geometrical Methods in the Theory of Ordinary Differential Equations" (Springer, 1988), we give an independent of coordinates formulation of general variational entropy inequalities for quasilinear equations of first order, that locally read as Kruzhkov inequalities, in terms of certain "entropy densities", and in the case of the equation of 2D flat projective structure we get the expression of the general entropy density from its abstract Rankine-Hugoniot rule for shocks using the projective geometry of the plane.

Gheorghe Minea

2009-12-04

288

Appendix B: Questionnaire B1: Questionnaire  

E-print Network

Appendix B: Questionnaire B1: Questionnaire #12;Do not write in this space To protect your child many children and adults currently live in the child's household? #12;12a. Please enter the number of children within each given age range that currently reside with the study child. Children 0-3 years old 4

289

Influence of Psychosocial Classroom Environment on Students' Motivation and Self-Regulation in Science Learning: A Structural Equation Modeling Approach  

NASA Astrophysics Data System (ADS)

The primary aim of this study was two-fold: 1) to identify salient psychosocial features of the classroom environment that influence students' motivation and self-regulation in science learning; and 2) to examine the effect of the motivational constructs of learning goal orientation, science task value and self-efficacy in science learning on students' self-regulation in science classrooms. Data collected from 1360 science students in grades 8, 9 and 10 in five public schools in Perth, Western Australia were utilized to validate the questionnaires and to investigate the hypothesized relationships. Structural Equation Modeling analysis suggested that student cohesiveness, investigation and task orientation were the most influential predictors of student motivation and self-regulation in science learning. In addition, learning goal orientation, task value and self-efficacy significantly influenced students' self-regulation in science. The findings offer potential opportunities for educators to plan and implement effective pedagogical strategies aimed at increasing students' motivation and self-regulation in science learning.

Velayutham, Sunitadevi; Aldridge, Jill M.

2013-04-01

290

The Strengths and Difficulties Questionnaire (SDQ)--Self-Report. An Analysis of Its Structure in a Multiethnic Urban Adolescent Sample  

ERIC Educational Resources Information Center

Background: The SDQ is currently one of the internationally most frequently used screening instruments for child and adolescent mental health purposes. However, its structure, cross-cultural equivalence, and its applicability in ethnic minority groups is still a matter of discussion. Methods: SDQ self-report data of 5,379 ethnic Norwegian and 865…

Richter, Jorg; Sagatun, Ase; Heyerdahl, Sonja; Oppedal, Brit; Roysamb, Espen

2011-01-01

291

Reassessment of the Psychometric Characteristics and Factor Structure of the 'Perceived Stress Questionnaire' (PSQ): Analysis in a Sample of Dental Students  

PubMed Central

Background The training to become a dentist can create psychological distress. The present study evaluates the structure of the ‘Perceived Stress Questionnaire’ (PSQ), its internal consistency model and interrelatedness with burnout, anxiety, depression and resilience among dental students. Methods The study employed a cross-sectional design. A sample of Spanish dental students (n?=?314) completed the PSQ, the ‘Goldberg Anxiety and Depression Scale’ (GADS), ‘Connor-Davidson Resilience Scale’ (10-item CD-RISC) and ‘Maslach Burnout Inventory-Student Survey’ (MBI-SS). The structure was estimated using Parallel Analysis from polychoric correlations. Unweighted Least Squares was the method for factor extraction, using the Item Response Theory to evaluate the discriminative power of items. Internal consistency was assessed by squaring the correlation between the latent true variable and the observed variable. The relationships between the PSQ and the other constructs were analysed using Spearman’s coefficient. Results The results showed a PSQ structure through two sub-factors (‘frustration’ and ‘tenseness’) with regard to one general factor (‘perceived stress’). Items that did not satisfy discriminative capacity were rejected. The model fit were acceptable (GFI?=?0.98; RSMR?=?0.06; AGFI?=?0.98; NFI?=?0.98; RFI?=?0.98). All the factors showed adequate internal consistency as measured by the congeneric model (?0.91). High and significant associations were observed between perceived stress and burnout, anxiety, depression and resilience. Conclusions The PSQ showed a hierarchical bi-factor structure among Spanish dental students. Using the questionnaire as a uni-dimensional scale may be useful in perceived stress level discrimination, while the sub-factors could help us to refine perceived stress analysis and improve therapeutic processes. PMID:24466330

Montero-Marin, Jesus; Piva Demarzo, Marcelo Marcos; Pereira, Joao Paulo; Olea, Marina; Garcia-Campayo, Javier

2014-01-01

292

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

E-print Network

The development of statistically efficient and computationally practicable estimation methods for the analysis of structural equation models with multiple nonlinear effects has been called for by substantive researchers in psychology, marketing research, and sociology. But the development of efficient methods is complicated by the fact that a nonlinear model structure implies specifically nonnormal multivariate distributions for the indicator variables. In this paper, nonlinear structural equation models with quadratic forms are introduced and a new Quasi-Maximum Likelihood method for simultaneous estimation of model parameters is developed with the focus on statistical efficiency and computational practicability. The Quasi-ML method is based on an approximation of the nonnormal density function of the joint indicator vector by a product of a normal and a conditionally normal density. The results of Monte-Carlo studies for the new Quasi-ML method indicate that the parameter estimation is almost as efficient as ML estimation, whereas ML estimation is only computationally practical for elementary models. Also, the Quasi-ML method outperforms other currently available methods with respect to efficiency. It is demonstrated in a Monte-Carlo study that the Quasi-ML method permits computationally feasible and very efficient analysis of models with multiple latent nonlinear effects. Finally, the applicability of the Quasi-ML method is illustrated by an empirical example of an aging study in psychology. Key words: structural equation modeling, quadratic form of normal variates, latent interaction effect, moderator effect, Quasi-ML estimation, variance function model. 1 1.

Andreas G. Klein; Bengt O. Muthén

293

Structure-function hierarchies and von Kármán-Howarth relations for turbulence in magnetohydrodynamical equations  

NASA Astrophysics Data System (ADS)

We generalize the method of A. M. Polyakov, [Phys. Rev. E 52, 6183 (1995), 10.1103/PhysRevE.52.6183] for obtaining structure-function relations in turbulence in the stochastically forced Burgers equation, to develop structure-function hierarchies for turbulence in three models for magnetohydrodynamics (MHD). These are the Burgers analogs of MHD in one dimension [Eur. Phys. J. B 9, 725 (1999), 10.1007/s100510050817], and in three dimensions (3DMHD and 3D Hall MHD). Our study provides a convenient and unified scheme for the development of structure-function hierarchies for turbulence in a variety of coupled hydrodynamical equations. For turbulence in the three sets of MHD equations mentioned above, we obtain exact relations for third-order structure functions and their derivatives; these expressions are the analogs of the von Kármán-Howarth relations for fluid turbulence. We compare our work with earlier studies of such relations in 3DMHD and 3D Hall MHD.

Basu, Abhik; Naji, Ali; Pandit, Rahul

2014-01-01

294

Travelling waves in a nonlocal reaction-diffusion equation as a model for a population structured by a space variable  

E-print Network

Travelling waves in a nonlocal reaction-diffusion equation as a model for a population structured by a space variable and a phenotypical trait Matthieu Alfaro 1 , Jérôme Coville 2 and Gaël Raoul 3 . Abstract We consider a nonlocal reaction-diffusion equation as a model for a population structured by a space

Paris-Sud XI, Université de

295

Evaluation of the Bayesian and Maximum Likelihood Approaches in Analyzing Structural Equation Models with Small Sample Sizes  

ERIC Educational Resources Information Center

The main objective of this article is to investigate the empirical performances of the Bayesian approach in analyzing structural equation models with small sample sizes. The traditional maximum likelihood (ML) is also included for comparison. In the context of a confirmatory factor analysis model and a structural equation model, simulation studies…

Lee, Sik-Yum; Song, Xin-Yuan

2004-01-01

296

Prediction of Shock Wave Structure in Weakly Ionized Gas Flow by Solving MGD Equation  

NASA Technical Reports Server (NTRS)

This paper reports the recent research results of shockwave structure predictions using a new developed code. The modified Rankine-Hugoniot relations across a standing normal shock wave are discussed and adopted to obtain jump conditions. Coupling a electrostatic body force to the Burnett equations, the weakly ionized flow field across the shock wave was solved. Results indicated that the Modified Rankine-Hugoniot equations for shock wave are valid for a wide range of ionization fraction. However, this model breaks down with small free stream Mach number and with large ionization fraction. The jump conditions also depend on the value of free stream pressure, temperature and density. The computed shock wave structure with ionization provides results, which indicated that shock wave strength may be reduced by existence of weakly ionized gas.

Deng, Z. T.; Oviedo-Rojas, Ruben; Chow, Alan; Litchford, Ron J.; Cook, Stephen (Technical Monitor)

2002-01-01

297

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

Microsoft Academic Search

This study explored the occurrence of self-concsious 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 affectivity—as an individual predisposition to experience highly negative emotions—predicted self-conscious emotions toward academic failure. However,

Temi Bidjerano

2010-01-01

298

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

299

Social cognitive determinants of physical activity in young adults: A prospective structural equation analysis  

Microsoft Academic Search

This study used a prospective design to test a model of the relation between social cognitive variables and physical activity\\u000a in a sample of 277 university students. Social support, self-efficacy, outcome expectations, and self-regulation were measured\\u000a at baseline and used to predict physical activity 8 weeks later. Results of structural equation modeling indicated a good\\u000a fit of the social cognitive

Liza S. Rovniak; Eileen S. Anderson; Richard A. Winett; Robert S. Stephens

2002-01-01

300

An ultra-short screening version of the Recalled Parental Rearing Behavior questionnaire (FEE-US) and its factor structure in a representative German sample  

PubMed Central

Background The Recalled Parental Rearing Behavior questionnaire (FEE, [1,2]) assesses perceived parental rearing behavior separately for each parent. An ultra-short screening version (FEE-US) with the same three scales each for the mother and the father is reported and factor-analytically validated. Methods N = 4,640 subjects aged 14 to 92 (M = 48.4 years) were selected by the random-route sampling method. The ultra-short questionnaire version was derived from the long version through item and factor analyses. In a confirmatory factor analysis framework, the hypothesized three-factorial structure was fitted to the empirical data and tested for measurement invariance, differential item functioning, item discriminability, and convergent and discriminant factorial validity. Effects of gender or age were assessed using MANOVAs. Results The a-priori hypothesized model resulted in mostly adequate overall fit. Neither gender nor age group yielded considerable effects on the factor structure, but had small effects on means of raw score sums. Factorial validities could be confirmed. Scale sums are well-suited to rank respondents along the respective latent dimension. Conclusion The structure of the long version with the factors Rejection & Punishment, Emotional Warmth, and Control & Overprotection could be replicated for both father and mother items in the ultra-short screening version using confirmatory factor analyses. These results indicate that the ultra-short screening version is a time-saving and promising screening instrument for research settings and in individual counseling. However, the shortened scales do not necessarily represent the full spectrum covered by the full-scale dimensions. PMID:23134704

2012-01-01

301

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

302

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

303

Measuring Metacognition in Cancer: Validation of the Metacognitions Questionnaire 30 (MCQ-30)  

PubMed Central

Objective The Metacognitions Questionnaire 30 assesses metacognitive beliefs and processes which are central to the metacognitive model of emotional disorder. As recent studies have begun to explore the utility of this model for understanding emotional distress after cancer diagnosis, it is important also to assess the validity of the Metacognitions Questionnaire 30 for use in cancer populations. Methods 229 patients with primary breast or prostate cancer completed the Metacognitions Questionnaire 30 and the Hospital Anxiety and Depression Scale pre-treatment and again 12 months later. The structure and validity of the Metacognitions Questionnaire 30 were assessed using factor analyses and structural equation modelling. Results Confirmatory and exploratory factor analyses provided evidence supporting the validity of the previously published 5-factor structure of the Metacognitions Questionnaire 30. Specifically, both pre-treatment and 12 months later, this solution provided the best fit to the data and all items loaded on their expected factors. Structural equation modelling indicated that two dimensions of metacognition (positive and negative beliefs about worry) were significantly associated with anxiety and depression as predicted, providing further evidence of validity. Conclusions These findings provide initial evidence that the Metacognitions Questionnaire 30 is a valid measure for use in cancer populations. PMID:25215527

Cook, Sharon A.; Salmon, Peter; Dunn, Graham; Fisher, Peter

2014-01-01

304

Analysis of frequency band structure in one-dimensional sonic crystal using Webster horn equation  

NASA Astrophysics Data System (ADS)

Sound propagation through periodic arrangement of scatterers lead to formation of bands of frequencies, known as band gaps, where sound cannot propagate though the structure. We propose a method based on Webster horn equation, along with Floquet theorem, to predict the band gap of a one-dimensional periodic structure made of hard sound-scatterers. The method is further modified to obtain the complex wave numbers, which give the decay constants. The decay constant is used to predict the sound attenuation of the evanescent wave in the finite sonic crystal. The theoretical prediction is verified with experimental measurements.

Gupta, A.; Lim, K. M.; Chew, C. H.

2011-05-01

305

Conversion of Questionnaire Data  

SciTech Connect

During the survey, respondents are asked to provide qualitative answers (well, adequate, needs improvement) on how well material control and accountability (MC&A) functions are being performed. These responses can be used to develop failure probabilities for basic events performed during routine operation of the MC&A systems. The failure frequencies for individual events may be used to estimate total system effectiveness using a fault tree in a probabilistic risk analysis (PRA). Numeric risk values are required for the PRA fault tree calculations that are performed to evaluate system effectiveness. So, the performance ratings in the questionnaire must be converted to relative risk values for all of the basic MC&A tasks performed in the facility. If a specific material protection, control, and accountability (MPC&A) task is being performed at the 'perfect' level, the task is considered to have a near zero risk of failure. If the task is performed at a less than perfect level, the deficiency in performance represents some risk of failure for the event. As the degree of deficiency in performance increases, the risk of failure increases. If a task that should be performed is not being performed, that task is in a state of failure. The failure probabilities of all basic events contribute to the total system risk. Conversion of questionnaire MPC&A system performance data to numeric values is a separate function from the process of completing the questionnaire. When specific questions in the questionnaire are answered, the focus is on correctly assessing and reporting, in an adjectival manner, the actual performance of the related MC&A function. Prior to conversion, consideration should not be given to the numeric value that will be assigned during the conversion process. In the conversion process, adjectival responses to questions on system performance are quantified based on a log normal scale typically used in human error analysis (see A.D. Swain and H.E. Guttmann, 'Handbook of Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications,' NUREG/CR-1278). This conversion produces the basic event risk of failure values required for the fault tree calculations. The fault tree is a deductive logic structure that corresponds to the operational nuclear MC&A system at a nuclear facility. The conventional Delphi process is a time-honored approach commonly used in the risk assessment field to extract numerical values for the failure rates of actions or activities when statistically significant data is absent.

Powell, Danny H [ORNL] [ORNL; Elwood Jr, Robert H [ORNL] [ORNL

2011-01-01

306

Subdiffusive master equation with space-dependent anomalous exponent and structural instability  

NASA Astrophysics Data System (ADS)

We derive the fractional master equation with space-dependent anomalous exponent. We analyze the asymptotic behavior of the corresponding lattice model both analytically and by Monte Carlo simulation. We show that the subdiffusive fractional equations with constant anomalous exponent ? in a bounded domain [0,L] are not structurally stable with respect to the nonhomogeneous variations of parameter ?. In particular, the Gibbs-Boltzmann distribution is no longer the stationary solution of the fractional Fokker-Planck equation whatever the space variation of the exponent might be. We analyze the random distribution of ? in space and find that in the long-time limit, the probability distribution is highly intermediate in space and the behavior is completely dominated by very unlikely events. We show that subdiffusive fractional equations with the nonuniform random distribution of anomalous exponent is an illustration of a “Black Swan,” the low probability event of the small value of the anomalous exponent that completely dominates the long-time behavior of subdiffusive systems.

Fedotov, Sergei; Falconer, Steven

2012-03-01

307

Subdiffusive master equation with space-dependent anomalous exponent and structural instability.  

PubMed

We derive the fractional master equation with space-dependent anomalous exponent. We analyze the asymptotic behavior of the corresponding lattice model both analytically and by Monte Carlo simulation. We show that the subdiffusive fractional equations with constant anomalous exponent ? in a bounded domain [0,L] are not structurally stable with respect to the nonhomogeneous variations of parameter ?. In particular, the Gibbs-Boltzmann distribution is no longer the stationary solution of the fractional Fokker-Planck equation whatever the space variation of the exponent might be. We analyze the random distribution of ? in space and find that in the long-time limit, the probability distribution is highly intermediate in space and the behavior is completely dominated by very unlikely events. We show that subdiffusive fractional equations with the nonuniform random distribution of anomalous exponent is an illustration of a "Black Swan," the low probability event of the small value of the anomalous exponent that completely dominates the long-time behavior of subdiffusive systems. PMID:22587063

Fedotov, Sergei; Falconer, Steven

2012-03-01

308

A stiffness equation transfer method for transient dynamic response analysis of structures  

NASA Astrophysics Data System (ADS)

A stiffness equation transfer method is proposed for transient dynamic response analysis of structures under various excitations. This method is a development and refinement of the combined finite element-transfer matrix (FE-TM) method. In the present method, the transfer of state vectors from left to right in the FE-TM method is changed into the transfer of general stiffness equations of every section from left to right. This method has the advantages of reducing the order of the ordinary transfer equation systems and minimizing the propagation of round-off errors occurring in recursive multiplication of transfer and point matrices. Furthermore, the drawback that the number of degrees of freedom on the left boundary must be the same as that on the right boundary in the ordinary FE-TM method, has now been avoided. The Newmark generalized acceleration formulation for time discretization is employed for a solution of the time problem. At the end, numerical examples are presented to demonstrate the accuracy as well as the potential of the proposed method for transient dynamic response analysis of structures.

Xue, Huiyu

2004-06-01

309

Characterizing the Shape of Anatomical Structures With Poisson’s Equation  

PubMed Central

Poisson’s equation, a fundamental partial differential equation in classical physics, has a number of properties that are interesting for shape analysis. In particular, the equipotential sets of the solution graph become smoother as the potential increases. We use the displacement map, the length of the streamlines formed by the gradient field of the solution, to measure the “complexity” (or smoothness) of the equipotential sets, and study its behavior as the potential increases. We believe that this function complexity = f (potential), which we call the shape characteristic, is a very natural way to express shape. Robust algorithms are presented to compute the solution to Poisson’s equation, the displacement map, and the shape characteristic. We first illustrate our technique on two-dimensional synthetic examples and natural silhouettes. We then perform two shape analysis studies on three-dimensional neuroanatomical data extracted from magnetic resonance (MR) images of the brain. In the first study, we investigate changes in the caudate nucleus in Schizotypal Personality Disorder (SPD) and confirm previously published results on this structure [1]. In the second study, we present a data set of caudate nuclei of premature infants with asymmetric white matter injury. Our method shows structural shape differences that volumetric measurements were unable to detect. PMID:17024829

Haidar, Haissam; Levitt, James J.; McCarley, Robert W.; Shenton, Martha E.; Soul, Janet S.

2009-01-01

310

Structure and decay constant of the {rho} meson within the Bethe-Salpeter equation  

SciTech Connect

In this article, we study the structure of the {rho} meson in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with a confining effective potential. The u and d quark propagators get significantly modified, the mass poles are absent in the timelike region, which implements confinement naturally. The Bethe-Salpeter amplitudes of the {rho} meson center around zero momentum and extend to the energy scale about q{sup 2}=1 GeV{sup 2}, which happens to be the energy scale of chiral symmetry breaking, strong interactions in the infrared region result in bound state. The numerical results of the mass and decay constant of the {rho} meson are in agreement with the experimental data.

Wang, Z. G. [Department of Physics, North China Electric Power University, Baoding 071003 (China); Wan, S. L. [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

2007-08-15

311

How the 2SLS/IV estimator can handle equality constraints in structural equation models: a system-of-equations approach.  

PubMed

Parameters in structural equation models are typically estimated using the maximum likelihood (ML) approach. Bollen (1996) proposed an alternative non-iterative, equation-by-equation estimator that uses instrumental variables. Although this two-stage least squares/instrumental variables (2SLS/IV) estimator has good statistical properties, one problem with its application is that parameter equality constraints cannot be imposed. This paper presents a mathematical solution to this problem that is based on an extension of the 2SLS/IV approach to a system of equations. We present an example in which our approach was used to examine strong longitudinal measurement invariance. We also investigated the new approach in a simulation study that compared it with ML in the examination of the equality of two latent regression coefficients and strong measurement invariance. Overall, the results show that the suggested approach is a useful extension of the original 2SLS/IV estimator and allows for the effective handling of equality constraints in structural equation models. PMID:24033324

Nestler, Steffen

2014-05-01

312

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. PMID:23243383

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

2012-01-01

313

The evolution of anisotropic structures and turbulence in the multi-dimensional Burgers equation  

E-print Network

The goal of the present paper is the investigation of the evolution of anisotropic regular structures and turbulence at large Reynolds number in the multi-dimensional Burgers equation. We show that we have local isotropization of the velocity and potential fields at small scale inside cellular zones. For periodic waves, we have simple decay inside of a frozen structure. The global structure at large times is determined by the initial correlations, and for short range correlated field, we have isotropization of turbulence. The other limit we consider is the final behavior of the field, when the processes of nonlinear and harmonic interactions are frozen, and the evolution of the field is determined only by the linear dissipation.

S. N. Gurbatov; A. Yu. Moshkov; A. Noullez

2008-08-20

314

The Herdecke questionnaire on quality of life (HLQ): Validation of factorial structure and development of a short form within a naturopathy treated in-patient collective  

PubMed Central

Background Quality of life (QoL) of patients has become a central evaluation parameter that also acts as an aid for decisions related to treatment strategies particularly for patients with chronic illnesses. In Germany, one of the newer instruments attempting to measure distinct QoL aspects is the "Herdecke Questionnaire for Quality of Life" (HLQ). In this study, we aimed to validate the HLQ with respect to its factorial structure, and to develop a short form. The validation has been carried out in relation to other questionnaires including the SF-36 Health Survey, the Mood-Scale Bf-S, the Giessen Physical Complaints Questionnaire GBB-24 and McGill's Pain Perception Scale SES. Methods Data for this study derived from a model project on the treatment of patients using naturopathy methods in Blankenstein Hospital, Hattingen. In total, 2,461 patients between the ages of 16 and 92 years (mean age: 58.0 ± 13.4 years) were included in this study. Most of the patients (62%) suffered from rheumatic diseases. Factorial validation of the HLQ, it's reliability and external consistency analysis and the development of a short form were carried out using the SPSS software. Results Structural analysis of the HLQ-items pointed to a 6-factor model. The internal consistency of both the long and the short version is excellent (Cronbach's ? is 0.935 for the HLQ-L and 0.862 for the HLQ-S). The highest reliability in the HLQ-L was obtained for the "Initiative Power and Interest" scale, the lowest for the 2-item scales "Digestive Well-Being" and the "Physical Complaints". However, the scales found by factor analysis herein were only in part congruent with the original 5-scale model which was approved a multitrait analysis approach. The new instrument shows good correlations with several scales of other relevant QoL instruments. The scales "Initiative Power and Interest", "Social Interaction", "Mental Balance", "Motility", "Physical Complaints", "Digestive Well-Being" sufficiently differentiate the diagnostic groups, particularly between the patients suffering on connective tissue and soft tissue disorders from those with metabolic and nutritional disorders or hypersensitivity reactions. Conclusion Both the factorial validation and the development of a consistent short-form of the HLQ are important steps forward for researchers in the field of QoL who wish to use the HLQ as a reliable and valid instrument. The results indicate that the HLQ is a unique QoL-instrument that can be used for both in-patient and out-patient-treatment. However, to improve to profile of the HLQ, there is still the need for strengthening the Questionnaire in the dimensions of physical well-being. This is the subject of a separate ongoing study. PMID:16004612

Ostermann, Thomas; Bussing, Arndt; Beer, Andre-Michael; Matthiessen, Peter F

2005-01-01

315

Predicting and understanding Korean high school students' science-track choice: Testing the theory of reasoned action by structural equation modeling  

NASA Astrophysics Data System (ADS)

The theory of reasoned action (Ajzen & Fishbein, 1980; Fishbein & Ajzen, 1975) was used to predict and understand Korean high school students' track choice for college entrance. First-year high school students (N = 665) from four representative regions of Korea participated in the study. The survey instruments were questionnaires developed according to the guidelines of the TRA. The target behavior of interest in this study was Korean students' choice of the science track when they completed the track application forms during the first year of high school. Predictors included TRA model and external variables. Multiple regression and the structural equation modeling with LISREL (Jöreskog & Sörbom, 1986) were used to analyze the data. The TRA was found to be applicable for understanding and predicting track choice, with minor modifications. Subjective norm was found to exert a direct influence on personal beliefs and the target behavior.

Myeong, Jeon-Ok; Crawley, Frank E.

316

Volume 88A, number 8 PHYSICS LETTERS 5 April 1982 ALGEBRAIC STRUCTURE OF THE PLASMA QUASILINEAR EQUATIONS {:;  

E-print Network

EQUATIONS {:;: Allan N. KAUFMAN Lawrence Berkeley Laboratory andPhysics Department, University of discovery [1] of a hamiltonian structure for the V1asov equation with Coulomb interaction (dis- covered~nd Institute for Fusion Studies, University of Texas, Austin, TX, USA. where H(p) is the single-particle energy

Morrison, Philip J.,

317

A combined finite element–stiffness equation transfer method for steady state vibration response analysis of structures  

Microsoft Academic Search

An extended finite element transfer matrix method, in combination with stiffness equation transfer, is applied to dynamic response analysis of the structures under periodic excitations. In the present method, the transfer of state vectors from left to right in a combined finite element-transfer matrix (FE-TM) method is changed into the transfer of general stiffness equations of every section from left

Huiyu Xue

2003-01-01

318

Direct and Indirect Effects of Education on Job Satisfaction: A Structural Equation Model for the Spanish Case  

ERIC Educational Resources Information Center

Empirical literature has traditionally analyzed the effect of education on job satisfaction with single-equation models that ignore interrelationships between theoretical explanatory variables. Their results are somewhat inconclusive. We propose estimating a structural equation model to obtain both the direct effects and the set of indirect…

Fabra, M. Eugenia; Camison, Cesar

2009-01-01

319

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.

320

Using Structural Equation Modeling to Assess Functional Connectivity in the Brain: Power and Sample Size Considerations  

PubMed Central

The present study assessed the impact of sample size on the power and fit of structural equation modeling applied to functional brain connectivity hypotheses. The data consisted of time-constrained minimum norm estimates of regional brain activity during performance of a reading task obtained with magnetoencephalography. Power analysis was first conducted for an autoregressive model with 5 latent variables (brain regions), each defined by 3 indicators (successive activity time bins). A series of simulations were then run by generating data from an existing pool of 51 typical readers (aged 7.5-12.5 years). Sample sizes ranged between 20 and 1,000 participants and for each sample size 1,000 replications were run. Results were evaluated using chi-square Type I errors, model convergence, mean RMSEA (root mean square error of approximation) values, confidence intervals of the RMSEA, structural path stability, and D-Fit index values. Results suggested that 70 to 80 participants were adequate to model relationships reflecting close to not so close fit as per MacCallum et al.'s recommendations. Sample sizes of 50 participants were associated with satisfactory fit. It is concluded that structural equation modeling is a viable methodology to model complex regional interdependencies in brain activation in pediatric populations.

Sideridis, Georgios; Simos, Panagiotis; Papanicolaou, Andrew; Fletcher, Jack

2014-01-01

321

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. PMID:18677423

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

2007-01-01

322

The Bjorken system of equations and nucleon spin structure-function data  

E-print Network

The status of the Bjorken sum rule is examined in the light of recent data on the spin structure functions of the deuteron and proton obtained by the SMC group, the neutron by the E142 group and the proton by the E143 group. Combining the new data with that already obtained for the proton by the EMC group and SLAC/YALE collaborations, we show that the Bjorken system of equations is violated at the 2-3 sigma level. We also discuss in detail the role of possible higher-twist contributions and higher-order PQCD corrections.

Ratcliffe, P G

1994-01-01

323

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

2013-08-01

324

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

PubMed

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. PMID:23649105

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

2013-05-29

325

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

326

High Risk Sexual Behaviors for HIV among the In-School Youth in Swaziland: A Structural Equation Modeling Approach  

PubMed Central

Background Global efforts in response to the increased prevalence of the human immunodeficiency virus (HIV) are mainly aimed at reducing high risk sexual behaviors among young people. However, knowledge regarding intentions of young people to engage in protective sexual behaviors is still lacking in many countries around the world, especially in Sub-Saharan Africa where prevalence of human immunodeficiency virus is the highest. The objective of this study was to test the theory of planned behavior (TPB) for predicting factors associated with protective sexual behaviors, including sexual abstinence and condom use, among in-school youths aged between 15 and 19 years in Swaziland. Methods This cross-sectional survey was conducted using a anonymous questionnaire. A two-stage stratified and cluster random sampling method was used. Approximately one hundred pupils from each of four schools agreed to participate in the study, providing a total sample size of 403 pupils of which 369 were ultimately included for data analysis. The response rate was 98%. Structural equation modeling was used to analyse hypothesized paths. Results The TPB model used in this study was effective in predicting protective sexual behavior among Swazi in-school youths, as shown by model fit indices. All hypothesized constructs significantly predicted intentions for abstinence and condom use, except perceived abstinence controls. Subjective norms were the strongest predictors of intention for premarital sexual abstinence; however, perceived controls for condom use were the strongest predictors of intention for condom use. Conclusions Our findings support application of the model in predicting determinants of condom use and abstinence intentions among Swazi in-school youths. PMID:23861756

Chu, Hsin; Liao, Yuan-Mei; Chen, Chiung-Hua; Ou, Keng-Liang; Chang, Lu-I; Chou, Kuei-Ru

2013-01-01

327

An examination of the construct validity of predictors of productive and counterproductive job performance using structural equation modeling  

E-print Network

This research used structural equation modeling to test the construct validity of measures I I ion, and work of four global constructs: trait socialization, self-concept, organizational socialization' concept. Using measurement model procedures...

Tice, Julie Anne Goodwin

2012-06-07

328

Testing the Effectiveness of Various Commonly Used Fit Indices for Detecting Misspecifications in Multilevel Structure Equation Models  

E-print Network

Two Monte Carlo studies were conducted to investigate the sensitivity of fit indices in detecting model misspecification in multilevel structural equation models (MSEM) with normally distributed or dichotomous outcome variables separately under...

Hsu, Hsien-Yuan

2011-02-22

329

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

330

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

331

Research on the Governance of Creditor's Rights and Growth of SMEs: An Empirical Analysis Based on Structure Equation Modeling  

Microsoft Academic Search

On the basis of Listed small and medium enterprise's(SMEs) empirical datum in China, this paper applying structure equation model (SEM) to research four dimensions of creditor's rights governance mechanism: solvency, debt financing level, assets maturity structure, debt maturity structure. And we do research on both theory and empirical analysis on the relationship between governance of creditor's rights, enterprise characteristics and

Wang Xiao-ding; Chen Xiao-hong; Zeng Jiang-hong

2007-01-01

332

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

333

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

334

A structural equation model to evaluate direct and indirect factors associated with a latent measure of mastitis in Belgian dairy herds.  

PubMed

In dairy cattle, many farming practices have been associated with occurrence of mastitis but it is often difficult to disentangle the causal threads. Structural equation models may reduce the complexity of such situations. Here, we applied the method to examine the links between mastitis (subclinical and clinical) and risk factors such as herd demographics, housing conditions, feeding procedures, milking practices, and strategies of mastitis prevention and treatment in 345 dairy herds from the Walloon region of Belgium. During the period January 2006 to October 2007, up to 110 different herd management variables were recorded by two surveyors using a questionnaire for the farm managers and during a farm visit. Monthly somatic cell counts of all lactating cows were collected by the local dairy herd improvement association. Structural equation models were created to obtain a latent measure of mastitis and to reduce the complexity of the relationships between farming practices, between indicators of herd mastitis and between both. Robust maximum likelihood estimates were obtained for the effects of the herd management variables on the latent measure of herd mastitis. Variables associated directly (p<0.05) with the latent measure of herd mastitis were the addition of urea in the rations; the practices of machine stripping, of pre-and post-milking teat disinfection; the presence of cows with hyperkeratotic teats, of cubicles for housing and of dirty liners before milking; the treatment of subclinical cases of mastitis; and the age of the herd (latent variable for average age and parity of cows, and percentage of heifers in the herd). Treatment of subclinical mastitis was also an intermediate in the association between herd mastitis and post-milking teat disinfection. The study illustrates how structural equation model provides information regarding the linear relationships between risk factors and a latent measure of mastitis, distinguishes between direct relationships and relationships mediated through intermediate risk factors, allows the construction of latent variables and tests the directional hypotheses proposed in the model. PMID:22770804

Detilleux, J; Theron, L; Beduin, J-M; Hanzen, C

2012-12-01

335

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. PMID:21975109

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

2011-01-01

336

Killing-Yano equations with torsion, worldline actions and G-structures  

E-print Network

We determine the geometry of the target spaces of supersymmetric non-relativistic particles with torsion and magnetic couplings, and with symmetries generated by the fundamental forms of G-structures for $G= U(n), SU(n), Sp(n), Sp(n)\\cdot Sp(1), G_2$ and $Spin(7)$. We find that the Killing-Yano equation, which arises as a condition for the invariance of the worldline action, does not always determine the torsion coupling uniquely in terms of the metric and fundamental forms. We show that there are several connections with skew-symmetric torsion for $G=U(n), SU(n)$ and $G_2$ that solve the invariance conditions. We describe all these compatible connections for each of the $G$-structures and explain the geometric nature of the couplings.

G. Papadopoulos

2011-11-29

337

Vector autoregression, structural equation modeling, and their synthesis in neuroimaging data analysis.  

PubMed

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 their 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 avoid some prevalent pitfalls that can occur when VAR and SEM are utilized separately. PMID:21975109

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

2011-12-01

338

Coaching Competency and (Exploratory) Structural Equation Modeling: A Substantive-Methodological Synergy  

PubMed Central

Objectives The purpose of this manuscript was to provide a substantive-methodological synergy of potential importance to future research in the psychology of sport and exercise. Design The substantive focus was the emerging role for, and particularly the measurement of, athletes’ evaluations of their coach's competency within conceptual models of effective coaching. The methodological focus was exploratory structural equation modeling (ESEM), a methodology that integrates the advantages of exploratory factor analysis and confirmatory factor analysis (CFA) within the general structural equation model. Method The synergy was a demonstration of when a new and flexible methodological framework, ESEM, may be preferred as compared to a more familiar and restrictive methodological framework, CFA, by reanalyzing existing data. Results ESEM analysis on extant datasets suggested that for responses to the Athletes’ Perceptions of Coaching Competency Scale II – High School Teams (APCCS II-HST), a CFA model based on the relevant literature plus one post hoc modification, offered a viable alternative to a more complex ESEM model. For responses to the Coaching Competency Scale (CCS), a CFA model based on the relevant literature did not offer a viable alternative to a more complex ESEM model. Conclusions The ESEM framework should be strongly considered in subsequent studies validity studies - for new and/or existing instruments in the psychology of sport and exercise. A key consideration for deciding between ESEM and the accompanying rotation criterion and CFA in future validity studies should be level of a priori measurement theory. PMID:23794951

Myers, Nicholas D.

2013-01-01

339

Actinide electronic structure based on the Dirac equation and density functional theory  

NASA Astrophysics Data System (ADS)

Density functional theory (DFT) provides a formally predictive basis for predicting the structural properties of actinides. Although available approximations to the exchange/correlation functional provide accurate predictions for many materials, they fail qualitatively and sometimes quantitatively when applied to actinides. Major contributors to this deficiency are an inadequate treatment of confinement physics and an incomplete treatment of relativity in the underlying equations. The development of a functional correctly incorporating confinement physics with a proper treatment of relativity would provide definitive, internally consistent predictions of actinide properties. To enable the development of such a functional and quantify the predictions of currently available functionals, we have developed an efficient first-principles electronic structure method based on the Dirac equation. Results are compared with current methods, and the implications for relativistic density functionals discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Wills, John M.; Mattsson, Ann E.

2013-03-01

340

Higher twist, polarised structure functions and the Bjorken system of equations  

E-print Network

We discuss the present situation with regard to polarised nucleon structure function measurements. In particular we examine the status of the Bjorken sum rule in the light of the recent data on the spin structure functions of (i) the deuteron obtained by the SMC group at CERN and (ii) the neutron by the E142 group at SLAC. In order to fully exploit all the available data it is necessary to study the complete Bjorken system of equations, which may be done in any of several equivalent ways. Combining the new data with that already obtained for the proton by the EMC group and earlier SLAC/YALE collaborations, together with bounds obtained on the strange quark polarisation, we show that the Bjorken system of equations is violated at about the 2 sigma level. We also show, using unpolarised data, that arguments based on possible higher-twist contributions are unable to account for this discrepancy. In conclusion, a simple explanation in terms of a non-perturbative renormalisation of the relevant Wilson coefficients...

Ratcliffe, P G

1994-01-01

341

Representing general theoretical concepts in structural equation models: The role of composite variables  

USGS Publications Warehouse

Structural equation modeling (SEM) holds the promise of providing natural scientists the capacity to evaluate complex multivariate hypotheses about ecological systems. Building on its predecessors, path analysis and factor analysis, SEM allows for the incorporation of both observed and unobserved (latent) variables into theoretically-based probabilistic models. In this paper we discuss the interface between theory and data in SEM and the use of an additional variable type, the composite. In simple terms, composite variables specify the influences of collections of other variables and can be helpful in modeling heterogeneous concepts of the sort commonly of interest to ecologists. While long recognized as a potentially important element of SEM, composite variables have received very limited use, in part because of a lack of theoretical consideration, but also because of difficulties that arise in parameter estimation when using conventional solution procedures. In this paper we present a framework for discussing composites and demonstrate how the use of partially-reduced-form models can help to overcome some of the parameter estimation and evaluation problems associated with models containing composites. Diagnostic procedures for evaluating the most appropriate and effective use of composites are illustrated with an example from the ecological literature. It is argued that an ability to incorporate composite variables into structural equation models may be particularly valuable in the study of natural systems, where concepts are frequently multifaceted and the influence of suites of variables are often of interest. ?? Springer Science+Business Media, LLC 2007.

Grace, J. B.; Bollen, K. A.

2008-01-01

342

Depth Averaged Equations Applied To Study of Defense Structures Effects On Dense Avalanche Flows  

NASA Astrophysics Data System (ADS)

Avalanche zoning and protection devices are the complementary tools used to assess avalanche risk and protect persons and human activities in mountainous areas. Despite the intensive use of defense structures as protection against avalanches, their hydraulic and structural effects are not well known. Many structures were designed empirically using expert knowledge or knowledge developed in other domain such as hydraulic. Defence structures effects in terms of energy dissipation, deviation and snow retention are difficult to study in situ. The cost and difficulties of experiments, the danger and the weak annual number of avalanches in a given site, are the reasons why scientists oriented their research towards the use of numerical or laboratory physical models. This paper presents and discuss the possibilities to use depth averaged equations to study dense avalanche flows around defence structures. The used numerical resolu- tion method is based on an upwind numerical scheme. Equations are integrated on each cell of the mesh and the numerical fluxes are calculated thanks to a simplified Riemann solver where the retained solution is obtained as a combination of shock and rarefaction founctions. This allows taking into account the topography variation and jets and surges presence. These two characteristics are needed because both exper- imental and in situ observations showed a significant topography modifications and jets and surges formations during interaction between avalanche flows and structures. The case of vertical surfaces such as those made of concrete destined to deviate flows are treated by appropriated boundary condition functions. A discussion about the best way to integrate defence structures in such model is presented and discussed. This modelisation has, in a first time, been tested on analytical solutions and on experimen- tal laboratory scale model results. These tests have shown the capacity of this model, despite the strong hypothesis, to reproduce correctly some experimentally observed characteristics. In a second phase, this model was applied to study a well documented real case where a large avalanche flow interacted with a complex protection device composed of several types of defence structures. This comparison showed a good con- formity between the numerical results and in-situ observations concerning the global characteristics of the flows such as the deposit and the trajectory of the avalanche.

Naaim, M.; Bouvet-Naaim, F.; Faug, T.; Lachamp, P.

343

Henry County School Questionnaire.  

ERIC Educational Resources Information Center

This 14-item questionnaire was designed to measure parent opinion regarding the effect of integration on third grade pupils in Henry County Schools. The questionnaire is not standardized, and field testing has been on a small scale. (See also TM 000 940 for a description of the study, and 942, 943 for the desegregation and school integration…

Goolsby, Thomas M., Jr.; Frary, Robert B.

344

Development of uncertainty-based work injury model using Bayesian structural equation modelling.  

PubMed

This paper proposed a Bayesian method-based structural equation model (SEM) of miners' work injury for an underground coal mine in India. The environmental and behavioural variables for work injury were identified and causal relationships were developed. For Bayesian modelling, prior distributions of SEM parameters are necessary to develop the model. In this paper, two approaches were adopted to obtain prior distribution for factor loading parameters and structural parameters of SEM. In the first approach, the prior distributions were considered as a fixed distribution function with specific parameter values, whereas, in the second approach, prior distributions of the parameters were generated from experts' opinions. The posterior distributions of these parameters were obtained by applying Bayesian rule. The Markov Chain Monte Carlo sampling in the form Gibbs sampling was applied for sampling from the posterior distribution. The results revealed that all coefficients of structural and measurement model parameters are statistically significant in experts' opinion-based priors, whereas, two coefficients are not statistically significant when fixed prior-based distributions are applied. The error statistics reveals that Bayesian structural model provides reasonably good fit of work injury with high coefficient of determination (0.91) and less mean squared error as compared to traditional SEM. PMID:24111548

Chatterjee, Snehamoy

2014-12-01

345

Application of high precision band structure calculations to the equation of state for beryllium oxide: SESAME equation of state number 7612  

SciTech Connect

High precision electronic band structure calculations for BeO have revealed a large volume discontinuity structural phase transition on the 0 K isotherm at about 1 Mbar. Although, this transition has not been observed experimentally, the accuracy of the calculations is such that the existence of this transition is unambiguous. A transition of this magnitude is likely to have a substantial impact on hydrodynamic simulations involving BeO. Here we report the creation of a new SESAME equations of state for BeO which incorporates the effect of the theoretically determined phase transition. This new EOS will be added to the SESAME library as material number 7612.

Boettger, J.C.; Wills, J.M.

1992-03-01

346

Behavioral questionnairesField implementation  

E-print Network

at risk for HIV: MSM, PWID and FSW. These standardized questionnaires are a resource for countries standardized behavioral questionnaires for MSM, PWID and FSW which can be utilized for implementing behavioral. Contents FSW questionnaire ........................................375 MSM questionnaire

Mullins, Dyche

347

The structural equation modeling analysis on the determinants of the corporate governance risk  

Microsoft Academic Search

This paper is to scientifically analyze the corporate governance risk factors based on the research results by some scholars both at home and abroad, and design the scales of questionnaires for corporate governance risk and relative influencing factors, targeting at the senior managers and corporate governance experts in listed corporate, carry out questionnaires and scales data analysis by SPSS and

Song Li; Yu Ting; Hu Yun-quan

2009-01-01

348

A structural equation model relating physical function, pain, impaired mobility (IM), and falls in older adults.  

PubMed

The current study used a structural equation model to investigate the interrelationships among physical function, pain, IM, and falls in 511 American older adults. The model included 11 measurement variables (tandem stance, single leg stance, 360° turn, chair stand, arm curl, sit and reach, back scratch, normative score of 6-min walk or 2-min step, timed up and go, pain, and fall) and four latent variables (balance, strength, flexibility, and IM). The final model with the combined sample demonstrated good fit with the participant data (?(2)(31)=30.0, N=499, p=0.52; Goodness of Fit Index (GFI)=0.99). Balance had a significant and the largest effect on IM (standardized regression weights=-1.05, p<0.001). Strength, endurance, flexibility, and pain had small effects on IM (standardized regression weights<0.2). The findings suggest that balance and mobility testing should be a priority in fall screening and prevention programs. PMID:22766209

Dai, Boyi; Ware, William B; Giuliani, Carol A

2012-01-01

349

Impact of oral health on physical and psychosocial dimensions: an analysis using structural equation modeling.  

PubMed

This study aimed to estimate the prevalence of impact of oral health conditions on physical and psychosocial dimensions among adolescents and to identify factors associated with severity of impact. The impact of oral health status was assessed by the instrument Oral Health Impact Profile (OHIP-14). The covariates were: socioeconomic status, habits and health care, use of dental services, and normative conditions of oral health. Structural equation modeling was performed, and 15.6% of adolescents reported impact in at least one dimension of the OHIP-14. The dimensions that showed the highest prevalence of impact were psychological distress (11.8%) and physical pain (6.6%). The number of teeth needing dental treatment, number of filled teeth, and CPI significantly affected severity of impact. In this adolescent population, unfavorable socioeconomic conditions were associated with reduced use of dental services, associated in turn with precarious oral health conditions and increased severity of impact. PMID:25099041

Silveira, Marise Fagundes; Marôco, João P; Freire, Rafael Silveira; Martins, Andréa Maria Eleutério de Barros Lima; Marcopito, Luiz Francisco

2014-06-01

350

Early-Life Socioeconomic Status and Physical Activity in Later Life: Evidence from Structural Equation Models  

PubMed Central

Objectives This study examines the association between early-life socioeconomic status (SES) at age 18 and physical activity (PA) at age 65, elucidates mechanisms explaining this association, and explores gender differences in mediating pathways. Methods Multi-group structural equation modeling is applied to the 1957–2004 data from the Wisconsin Longitudinal Study. Results Early-life SES is positively associated with exercise in later life. This association is mediated by socioeconomic resources, health problems, obesity, and depressive symptoms (women only) in 1993 and sports participation in 1957. All mediators explain over 95% of the effect of early-life SES. Discussion This study emphasizes the importance of complex multiple pathways linking early family SES to later-life PA. We identify chains of risks that need to be broken to improve PA among older adults. Our findings also suggest that interventions aimed at maintaining optimal physical functioning in old age should begin at least at midlife. PMID:23248349

Pudrovska, Tetyana; Aniskin, Andriy

2014-01-01

351

IT vendor selection model by using structural equation model & analytical hierarchy process  

NASA Astrophysics Data System (ADS)

Selecting and evaluating the right vendors is imperative for an organization's global marketplace competitiveness. Improper selection and evaluation of potential vendors can dwarf an organization's supply chain performance. Numerous studies have demonstrated that firms consider multiple criteria when selecting key vendors. This research intends to develop a new hybrid model for vendor selection process with better decision making. The new proposed model provides a suitable tool for assisting decision makers and managers to make the right decisions and select the most suitable vendor. This paper proposes a Hybrid model based on Structural Equation Model (SEM) and Analytical Hierarchy Process (AHP) for long-term strategic vendor selection problems. The five steps framework of the model has been designed after the thorough literature study. The proposed hybrid model will be applied using a real life case study to assess its effectiveness. In addition, What-if analysis technique will be used for model validation purpose.

Maitra, Sarit; Dominic, P. D. D.

2012-11-01

352

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. PMID:22429193

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

2012-01-01

353

Should researchers use single indicators, best indicators, or multiple indicators in structural equation models?  

PubMed Central

Background Structural equation modeling developed as a statistical melding of path analysis and factor analysis that obscured a fundamental tension between a factor preference for multiple indicators and path modeling’s openness to fewer indicators. Discussion Multiple indicators hamper theory by unnecessarily restricting the number of modeled latents. Using the few best indicators – possibly even the single best indicator of each latent – encourages development of theoretically sophisticated models. Additional latent variables permit stronger statistical control of potential confounders, and encourage detailed investigation of mediating causal mechanisms. Summary We recommend the use of the few best indicators. One or two indicators are often sufficient, but three indicators may occasionally be helpful. More than three indicators are rarely warranted because additional redundant indicators provide less research benefit than single indicators of additional latent variables. Scales created from multiple indicators can introduce additional problems, and are prone to being less desirable than either single or multiple indicators. PMID:23088287

2012-01-01

354

Analyzing average and conditional effects with multigroup multilevel structural equation models  

PubMed Central

Conventionally, multilevel analysis of covariance (ML-ANCOVA) has been the recommended approach for analyzing treatment effects in quasi-experimental multilevel designs with treatment application at the cluster-level. In this paper, we introduce the generalized ML-ANCOVA with linear effect functions that identifies average and conditional treatment effects in the presence of treatment-covariate interactions. We show how the generalized ML-ANCOVA model can be estimated with multigroup multilevel structural equation models that offer considerable advantages compared to traditional ML-ANCOVA. The proposed model takes into account measurement error in the covariates, sampling error in contextual covariates, treatment-covariate interactions, and stochastic predictors. We illustrate the implementation of ML-ANCOVA with an example from educational effectiveness research where we estimate average and conditional effects of early transition to secondary schooling on reading comprehension. PMID:24795668

Mayer, Axel; Nagengast, Benjamin; Fletcher, John; Steyer, Rolf

2014-01-01

355

Prediction of attitudes towards restrictive AIDS policies: a structural equation modelling approach.  

PubMed

The purpose of the study was to test a prehypothesized structural equation model of predictors of attitudes towards restrictive AIDS policies. It was assumed that such attitudes ae under influence of both cognitive processes and more general attitudinal structures. The hypothesized model was tested against empirical data from a nation-wide survey of Norwegian adults, including 543 males and 577 females. The proposed model fit the data reasonably well. As expressed by total effect education was the most important predictor of AIS policy attitudes. However, the most notable findings appeared to be the strong direct effect exerted by attitudes towards minorities. Misinformation about AIDS transmission and sexual attitudes also exerted significant direct effects upon AIDS policy attitudes. The results clearly demonstrate that AIDS policy attitudes are not cognitively based alone but also reflect more general attitudinal structures. Thus choosing a strategy which is primarily based on increasing the flow of factual AIDS information in order to remedy casual contact beliefs, will not be sufficient to prevent stigmatized and negative AIDS attitudes. This is more evident in that beliefs about modes of AIDS transmission, as reported in this study, seem themselves to have a symbolic component. A perspective which includes the idea of the value expressive functions of AIDS related attitudes seem relevant. Consequently, educational strategies which directly address prejudiced attitudes towards minority groups may prove particularly appropriate in the prevention of stigmatized and restrictive AIDS attitudes. PMID:7747205

Kraft, P; Rise, J

1995-03-01

356

Thalamic-insular dysconnectivity in schizophrenia: evidence from structural equation modeling.  

PubMed

Structural and functional studies have shown that schizophrenia is often associated with frontolimbic abnormalities in the prefrontal and mediotemporal regions. It is still unclear, however, if such dysfunctional interaction extends as well to relay regions such as the thalamus and the anterior insula. Here, we measured gray matter volumes of five right-hemisphere regions in 68 patients with schizophrenia and 77 matched healthy subjects. The regions were amygdala, thalamus, and entorhinal cortex (identified as anomalous by prior studies on the same population) and dorsolateral prefrontal cortex and anterior insula (isolated by voxel-based morphometry analysis). We used structural equation modeling and found altered path coefficients connecting the thalamus to the anterior insula, the amygdala to the DLPFC, and the entorhinal cortex to the DLPFC. In particular, patients exhibited a stronger thalamus-insular connection than healthy controls. Instead, controls showed positive entorhinal-DLPFC and negative amygdalar-DLPFC connections, both of which were absent in the clinical population. Our data provide evidence that schizophrenia is characterized by an impaired right-hemisphere network, in which intrahemispheric communication involving relay structures may play a major role in sustaining the pathophysiology of the disease. PMID:21484952

Corradi-Dell'Acqua, Corrado; Tomelleri, Luisa; Bellani, Marcella; Rambaldelli, Gianluca; Cerini, Roberto; Pozzi-Mucelli, Roberto; Balestrieri, Matteo; Tansella, Michele; Brambilla, Paolo

2012-03-01

357

Writing a Questionnaire Report.  

ERIC Educational Resources Information Center

Outlines a plan to provide practice in writing questionnaire reports. Teaches students: (1) how to know what report format is appropriate; (2) how to interpret and present statistical data; and (3) what recommendations to make, if any. (RAE)

Spring, Marietta

1988-01-01

358

Questionnaire for Evaluation Skills.  

ERIC Educational Resources Information Center

This is a 20-item, three part questionnaire designed to measure knowledge of decision-making and evaluation on the part of participants in a training program on planning and evaluation. Part of TM 001 078. (DLG)

Radcliffe, Vickey W.; Colgan, Francis E.

359

Impaired self-awareness after traumatic brain injury: inter-rater reliability and factor structure of the Dysexecutive Questionnaire (DEX) in patients, significant others and clinicians  

PubMed Central

Aims: This study sought to address two questions: (1) what is the inter-rater reliability of the Dysexecutive Questionnaire (DEX) when completed by patients, their significant others, and clinicians; and (2) does the factor structure of the DEX vary for these three groups? Methods: We obtained DEX ratings for 113 patients with an acquired brain injury from two brain injury services in the UK and two services in Ireland. We gathered data from two groups of raters—“significant others” (DEX-SO) such as partners and close family members and “clinicians” (DEX-C), who were psychologists or rehabilitation physicians working closely with the patient and who were able to provide an opinion about the patient’s level of everyday executive functioning. Intra-class correlation coefficients and their 95% confidence intervals were calculated between each of the three groups (self, significant other, clinician). Principal axis factor (PAF) analyses were also conducted for each of the three groups. Results: The factor analysis revealed a consistent one-factor model for each of the three groups of raters. However, the inter-rater reliability analyses showed a low level of agreement between the self-ratings and the ratings of the two groups of independent raters. We also found low agreement between the significant others and the clinicians. Conclusion: Although there was a consistent finding of a single factor solution for each of the three groups, the low level of agreement between significant others and clinicians raises a question about the reliability of the DEX. PMID:25346668

McGuire, Brian E.; Morrison, Todd G.; Barker, Lynne A.; Morton, Nicholas; McBrinn, Judith; Caldwell, Sheena; Wilson, Colin F.; McCann, John; Carton, Simone; Delargy, Mark; Walsh, Jane

2014-01-01

360

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

361

Ab initio studies of equations of state and chemical reactions of reactive structural materials  

NASA Astrophysics Data System (ADS)

The motivations for the research issues addressed in this thesis are based on the needs of the aerospace structural analysis and the design community. The specific focus is related to the characterization and shock induced chemical reactions of multi-functional structural-energetic materials that are also known as the reactive structural materials and their reaction capabilities. Usually motivation for selection of aerospace structural materials is to realize required strength characteristics and favorable strength to weight ratios. The term strength implies resistance to loads experienced during the service life of the structure, including resistance to fatigue loads, corrosion and other extreme conditions. Thus, basically the structural materials are single function materials that resist loads experienced during the service life of the structure. However, it is desirable to select materials that are capable of offering more than one basic function of strength. Very often, the second function is the capability to provide functions of sensing and actuation. In this thesis, the second function is different. The second function is the energetic characteristics. Thus, the choice of dual functions of the material are the structural characteristics and energetic characteristics. These materials are also known by other names such as the reactive material structures or dual functional structural energetic materials. Specifically the selected reactive materials include mixtures of selected metals and metal oxides that are also known as thermite mixtures, reacting intermetallic combinations and oxidizing materials. There are several techniques that are available to synthesize these structural energetic materials or reactive material structures and new synthesis techniques constitute an open research area. The focus of this thesis, however, is the characterization of chemical reactions of reactive material structures that involve two or more solids (or condensed matter). The subject of studies of the shock or thermally induced chemical reactions of the two solids comprising these reactive materials, from first principles, is a relatively new field of study. The published literature on ab initio techniques or quantum mechanics based approaches consists of the ab initio or ab initio-molecular dynamics studies in related fields that contain a solid and a gas. One such study in the literature involves a gas and a solid. This is an investigation of the adsorption of gasses such as carbon monoxide (CO) on Tungsten. The motivation for these studies is to synthesize alternate or synthetic fuel technology by Fischer-Tropsch process. In this thesis these studies are first to establish the procedure for solid-solid reaction and then to extend that to consider the effects of mechanical strain and temperature on the binding energy and chemisorptions of CO on tungsten. Then in this thesis, similar studies are also conducted on the effect of mechanical strain and temperature on the binding energies of Titanium and hydrogen. The motivations are again to understand the method and extend the method to such solid-solid reactions. A second motivation is to seek strained conditions that favor hydrogen storage and strain conditions that release hydrogen easily when needed. Following the establishment of ab initio and ab initio studies of chemical reactions between a solid and a gas, the next step of research is to study thermally induced chemical reaction between two solids (Ni+Al). Thus, specific new studies of the thesis are as follows: (1) Ab initio Studies of Binding energies associated with chemisorption of (a) CO on W surfaces (111, and 100) at elevated temperatures and strains and (b) adsorption of hydrogen in titanium base. (2) Equations of state of mixtures of reactive material structures from ab initio methods. (3) Ab initio studies of the reaction initiation, transition states and reaction products of intermetallic mixtures of (Ni+Al) at elevated temperatures and strains. (4) Press-cure synthesis of Nano-nickel and nano-aluminum based reacti

Zaharieva, Roussislava

362

The Simple Nonpolar Continuum Media. Part II. the Constitutive Equations. Linear Structures  

E-print Network

A method for obtaining the constitutive equations for describing the simple nonpolar continuum media is given. The method is based on the theory of Lie groups and on group properties of the differential equations.

V. O. Bytev

2009-06-10

363

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. PMID:21037082

Tanaka, Noriko; Huttenhower, Curtis; Nosho, Katsuhiko; Baba, Yoshifumi; Shima, Kaori; Quackenbush, John; Haigis, Kevin M.; Giovannucci, Edward; Fuchs, Charles S.; Ogino, Shuji

2010-01-01

364

1D band structure of single periodic scatterer in Schrodinger equation  

E-print Network

GLOBAL SOLUTIONS FOR 3D QUADRATIC SCHR¨ODINGER EQUATIONS P. GERMAIN, N. MASMOUDI AND J. SHATAH that this naturally suggests, leads to a simple proof of global existence and scattering for quadratic nonlinear Schr¨odinger existence of small solutions to nonlinear Schr¨odinger (NLS) equations. A prototype of these equations is tu

Barnett, Alex

365

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

366

The Dirac equation in electronic structure calculations: Accurate evaluation of DFT predictions for actinides  

SciTech Connect

Brooks, Johansson, and Skriver, using the LMTO-ASA method and considerable insight, were able to explain many of the ground state properties of the actinides. In the many years since this work was done, electronic structure calculations of increasing sophistication have been applied to actinide elements and compounds, attempting to quantify the applicability of DFT to actinides and actinide compounds and to try to incorporate other methodologies (i.e. DMFT) into DFT calculations. Through these calculations, the limits of both available density functionals and ad hoc methodologies are starting to become clear. However, it has also become clear that approximations used to incorporate relativity are not adequate to provide rigorous tests of the underlying equations of DFT, not to mention ad hoc additions. In this talk, we describe the result of full-potential LMTO calculations for the elemental actinides, comparing results obtained with a full Dirac basis with those obtained from scalar-relativistic bases, with and without variational spin-orbit. This comparison shows that the scalar relativistic treatment of actinides does not have sufficient accuracy to provide a rigorous test of theory and that variational spin-orbit introduces uncontrolled errors in the results of electronic structure calculations on actinide elements.

Wills, John M [Los Alamos National Laboratory; Mattsson, Ann E [Sandia National Laboratories

2012-06-06

367

Modeling Alcohol Use Disorder Severity: An Integrative Structural Equation Modeling Approach  

PubMed Central

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.

2013-01-01

368

Microscopic structure and thermodynamics of a core-softened model fluid from the second-order integral equations theory  

E-print Network

We have studied the structure and thermodynamic properties of isotropic three-dimensional core-softened fluid by using the second-order Ornstein-Zernike integral equations completed by the hypernetted chain and Percus-Yevick closures. The radial distribution functions are compared with those from singlet integral equations and with computer simulation data. The limits of the region of density anomaly resulting from different approximate theories are established. The obtained results show that the second-order hypernetted chain approximation can be used to describe both the structure and the density anomaly of this model fluid. Moreover, we present the results of calculations of the bridge functions.

O. Pizio; Z. Sokolowska; S. Sokolowski

2011-06-16

369

Wronskian and Grammian determinant structure solutions for a variable-coefficient forced Kadomtsev-Petviashvili equation in fluid dynamics  

NASA Astrophysics Data System (ADS)

Taking the inhomogeneities of media and nonuniform boundaries into account, the variable-coefficient equations can describe more realistic physical phenomena than their constant-coefficient counterparts. In this paper, a variable-coefficient forced Kadomtsev-Petviashvili equation with inhomogeneous nonlinearity, dispersion, perturbed term and external force is investigated. Using a modified dependent variable transformation, this equation is first bilinearized. Then, the N-soliton solutions in two different kinds of determinant structure, that is the Wronskian and Grammian determinant soliton solutions for the variable-coefficient forced Kadomtsev-Petviashvili equation are presented and verified under certain coefficient constraints. The sample soliton solutions are given by choosing suitable determinant elements, and several kinds of soliton evolution situations are discussed and illustrated.

Meng, Xiang-Hua

2014-11-01

370

Canonical structure of evolution equations with non-linear dispersive terms  

NASA Astrophysics Data System (ADS)

The inverse problem of the variational calculus for evolution equations characterized by non-linear dispersive terms is analysed with a view to clarify why such a system does not follow from Lagrangians. Conditions are derived under which one could construct similar equations which admit a Lagrangian representation. It is shown that the system of equations thus obtained can be Hamiltonized by making use of the Dirac's theory of constraints. The specific results presented refer to the third- and fifth-order equations of the so-called distinguished subclass.

Talukdar, B.; Shamanna, J.; Ghosh, S.

2003-07-01

371

Young adults' knowledge of politics: evaluating the role of socio-cognitive variables using structural equations.  

PubMed

The aim of this study was to create an explanatory model that allows analyzing the predictive power of a set of variables related to political knowledge; more specifically, to analyze the relationship between the education level of young adults and the variables, interest in politics and internal political efficacy. We also analyzed the combined relationship between these variables, together with age, and political knowledge. We worked with a sample group of 280 young adults between the ages of 18-30 from the city of Córdoba (Argentina). The data was subjected to a structural equation modelling SEM analysis, which allowed for the corroboration of the following hypotheses: the higher the education level, the more the interest in politics; the higher the education level, the better the perception of internal political efficacy; the higher the education level, the more the political knowledge; the more the interest in politics, the more the political knowledge; and the better the perception of internal political efficacy, the more interest in politics. Moreover, the following hypotheses could not be verified: the older an individual, the more the political knowledge; and the better the perception of internal political efficacy, the more the political knowledge. The model obtained allows for discussion of the explanatory value of these socio-cognitive variables. PMID:21568176

Brussino, Silvina; Medrano, Leonardo; Sorribas, Patricia; Rabbia, Hugo H

2011-05-01

372

Coaching competency and satisfaction with the coach: a multi-level structural equation model.  

PubMed

The purpose of this initial predictive validity study was to determine the ability of measures derived from the Athletes' Perceptions of Coaching Competency Scale II - High School Teams (APCCS II-HST) to predict satisfaction with the head coach. Specification of the statistical model was informed by the mediational model of coach-athlete interactions. The technical quality of the satisfaction measure was evaluated before testing the predictive validity of the coaching competency measures. Data were collected from athletes of seven sports. Athlete observations (N = 748) were clustered within teams (G = 74). Multi-group confirmatory factor analyses (CFA) provided evidence for factorial invariance of a reduced version of the satisfaction measure by athlete gender. Multi-level CFA provided evidence of model-data consistency for a reduced version of the satisfaction measure. Multi-level structural equation modelling provided evidence for the ability of latent coaching competency to positively predict latent satisfaction at both the athlete level (technique competency and motivation competency) and the team level (coaching competency) and for close model-data fit. Implications of this study include: that the APCCS II-HST should be viewed as a replacement for the Coaching Competency Scale when the intended population is appropriate; a preliminary multi-level measurement model for satisfaction with one's coach that should be considered as a potential starting point in subsequent studies; and empirical support for a key relationship proposed in the mediational model of coach-athlete interactions. PMID:21184342

Myers, Nicholas D; Beauchamp, Mark R; Chase, Melissa A

2011-02-01

373

Psychological contract breach and outcomes: Combining meta-analysis and structural equation models.  

PubMed

In this study, meta-analytic procedures were used to examine the relationships between psychological contract perceived breach and certain outcome variables, such as organizational commitment, job satisfaction and organizational citizenship behaviours (OCB). Our review of the literature generated 41 independent samples in which perceived breach was used as a predictor of these personal and organizational outcomes. A medium effect size (ES) for desirable outcomes (job satisfaction, organizational commitment, organizational trust, OCB and performance) was obtained (r=-.35). For undesirable outcomes (neglect in role duties and intention to leave), ES were also medium (r=.31). When comparing attitudinal (job satisfaction, organizational commitment, organizational trust) and behavioural outcomes (OCB, neglect in role duties and performance), a stronger ES was found for attitudinal (r=-.24) than for behavioural outcomes (r=-.11). Potential moderator variables were examined, and it was found that they explained only a percentage of variability of primary studies. Structural equation analysis of the pooled meta-analytical correlation matrix indicated that the relationships of perceived breach with satisfaction, OCB, intention to leave and performance are fully mediated by organizational trust and commitment. Results are discussed in order to suggest theoretical and empirical implications. PMID:18674448

Topa Cantisano, Gabriela; Morales Domínguez, J Francisco; Depolo, Marco

2008-08-01

374

Road traffic noise, sensitivity, annoyance and self-reported health--a structural equation model exercise.  

PubMed

The proposed effect of road traffic noise on hypertension and ischemic heart disease finds mixed empirical support. One problem with many studies is that the directions of the causal relationships are not identified. This is often the case when cross-sectional data and multivariate regression models are utilised. The aim of the study was to explore the relationship between road traffic noise and health. More specifically the relationships between noise complaints, noise sensitivity and subjectively reported hypertension and heart problems were investigated. 1842 respondents in Oslo, Norway were interviewed about their experience of the local environment and their subjective health complaints. The interviews were conducted as part of two surveys. Individual measures of air pollution (NO(2)) and noise (Lden) were calculated. The data were analysed using Structural Equation Models. Only sensitivity to noise is related to hypertension and chest pain. No relationships between noise exposure and health complaints were identified. Rather than noise being the causal agent leading to health problems, the results suggest that the noise-health relationships in these studies may be spurious. It is conceivable that individual vulnerability is reflected both in ill health and in being sensitive to noise. The benefit of including more contextual variables in a model of noise-health relationships is supported. PMID:18823662

Fyhri, Aslak; Klaeboe, Ronny

2009-01-01

375

Static solitons of the sine-Gordon equation and equilibrium vortex structure in Josephson junctions  

SciTech Connect

The problem of vortex structure in a single Josephson junction in an external magnetic field, in the absence of transport currents, is reconsidered from a new mathematical point of view. In particular, we derive a complete set of exact analytical solutions representing all the stationary points (minima and saddle-points) of the relevant Gibbs free-energy functional. The type of these solutions is determined by explicit evaluation of the second variation of the Gibbs free-energy functional. The stable (physical) solutions minimizing the Gibbs free-energy functional form an infinite set and are labeled by a topological number N{sub v}=0,1,2,... . Mathematically, they can be interpreted as nontrivial 'vacuum' (N{sub v}=0) and static topological solitons (N{sub v}=1,2,...) of the sine-Gordon equation for the phase difference in a finite spatial interval: solutions of this kind were not considered in previous literature. Physically, they represent the Meissner state (N{sub v}=0) and Josephson vortices (N{sub v}=1,2,...). Major properties of the new physical solutions are thoroughly discussed. An exact, closed-form analytical expression for the Gibbs free energy is derived and analyzed numerically. Unstable (saddle-point) solutions are also classified and discussed.

Kuplevakhsky, S. V.; Glukhov, A. M. [B. I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, 61103 Kharkov (Ukraine)

2006-01-01

376

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. PMID:18387823

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

377

Network inference of AP pattern formation system in D.melanogaster by structural equation modeling  

NASA Astrophysics Data System (ADS)

Within the field of systems biology, revealing the control systems functioning during embryogenesis is an important task. To clarify the mechanisms controlling sequential events, the relationships between various factors and the expression of specific genes should be determined. In this study, we applied a method based on Structural Equation Modeling (SEM), combined with factor analysis. SEM can include the latent variables within the constructed model and infer the relationships among the latent and observed variables, as a network model. We improved a method for the construction of initial models for the SEM calculation, and applied our approach to estimate the regulatory network for Antero-Posterior (AP) pattern formation in D. melanogaster embryogenesis. In this new approach, we combined cross-correlation and partial correlation to summarize the temporal information and to extract the direct interactions from the gene expression profiles. In the inferred model, 18 transcription factor genes were regulated by not only the expression of other genes, but also the estimated factors. Since each factor regulated the same type of genes, these factors were considered to be involved in maternal effects or spatial morphogen distributions. The interpretation of the inferred network model allowed us to reveal the regulatory mechanism for the patterning along the head to tail axis in D. melanogaster.

Aburatani, S.; Toh, H.

2014-03-01

378

A structural equation modeling of the factors affecting student nurses' medication errors.  

PubMed

Across medication error literature, much attention has been given to incidence, types, causes and prevention of medication errors. Despite these efforts, medication errors continue to occur among registered and student nurses. Considering the numerous studies on medication errors committed by registered nurses, little is known on the nature of student nurses' medication error. This study employed factor analysis and structural equation modeling to explore the factors affecting medication errors by student nurses. With the participation of 329 junior and senior student nurses recruited from a comprehensive university in the Philippines, five factor dimensions of the causes of student nurses' medication error were identified, namely: In-violation, In-writing, In-excess, In-experience and In-tension. Results of path analysis showed an interaction among these variables. Additionally, poor adherence to the "five rights" was identified as an important mediator between In-violation, In-writing, In-excess, In-experience and In-tension and student nurses' medication error. By developing a model to explain how student nurses' medication errors occur, this study sheds light on the nature of student nurses' medication error and provides a basis for error prevention strategies. PMID:22325830

Valdez, Les Paul; de Guzman, Allan; Escolar-Chua, Rowena

2013-03-01

379

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

380

Stress and Resilience in Functional Somatic Syndromes – A Structural Equation Modeling Approach  

PubMed Central

Background Stress has been suggested to play a role in the development and perpetuation of functional somatic syndromes. The mechanisms of how this might occur are not clear. Purpose We propose a multi-dimensional stress model which posits that childhood trauma increases adult stress reactivity (i.e., an individual's tendency to respond strongly to stressors) and reduces resilience (e.g., the belief in one's competence). This in turn facilitates the manifestation of functional somatic syndromes via chronic stress. We tested this model cross-sectionally and prospectively. Methods Young adults participated in a web survey at two time points. Structural equation modeling was used to test our model. The final sample consisted of 3?054 participants, and 429 of these participated in the follow-up survey. Results Our proposed model fit the data in the cross-sectional (?2(21) ?=?48.808, p<.001, CFI ?=?.995, TLI ?=?.992, RMSEA ?=?.021, 90% CI [.013.029]) and prospective analyses (?2(21) ?=?32.675, p<.05, CFI ?=?.982, TLI ?=?.969, RMSEA ?=?.036, 90% CI [.001.059]). Discussion Our findings have several clinical implications, suggesting a role for stress management training in the prevention and treatment of functional somatic syndromes. PMID:25396736

Fischer, Susanne; Lemmer, Gunnar; Gollwitzer, Mario; Nater, Urs M.

2014-01-01

381

Mercury cycling in aquatic ecosystems and trophic state-related variables - Implications from structural equation modeling.  

PubMed

Structural equation modeling (SEM) provides a framework that can more properly handle complex variable interactions inherent in mercury cycling and its bioaccumulation compared to more traditional regression-based methods. SEM was applied to regional data sets for three different types of aquatic ecosystems within Florida, USA - lakes, streams, and the Everglades - to evaluate the underlying nature (i.e., indirect and direct) of the relationships between fish mercury concentrations and trophic state related variables such as nutrients, dissolved organic carbon (DOC), sulfate, and alkalinity. The modeling results indicated some differences in key variable relationships - for example, the effect of nutrients on fish mercury in lakes and streams was uniformly negative through direct and indirect pathways consistent with biodilution or eutrophication-associated effects on food web structure. Somewhat surprisingly, however, was that total phosphorus did not serve as a meaningful variable in the Everglades model, apparently because its effects were masked or secondary to the effects of DOC. What is perhaps a more important result were two key similarities across the three systems. First, the modeling clearly indicates that the dominant influence on fish tissue mercury concentrations in all three systems is related to variations in the methylmercury signal. Second, the modeling demonstrated that the effect of DOC on fish mercury concentrations was exerted through multiple and antagonistic pathways, including facilitated transport of total mercury and methylmercury, enhanced rates of methylation, and limitations imposed on bioavailability. Indeed, while the individual DOC pathways in the models were all highly significant (generally p<0.001), the net effect of DOC in each model was greatly reduced or insignificant. These results can help explain contradictory results obtained previously by other researchers in other systems, and illustrate the importance of SEM as a modeling tool when studying systems with complex interactions such as the aquatic mercury cycle. PMID:25173863

Pollman, Curtis D

2014-11-15

382

Pediatric Health-Related Quality of Life: A Structural Equation Modeling Approach  

PubMed Central

Objectives One of the most referenced theoretical frameworks to measure Health Related Quality of Life (HRQoL) is the Wilson and Cleary framework. With some adaptions this framework has been validated in the adult population, but has not been tested in pediatric populations. Our goal was to empirically investigate it in children. Methods The contributory factors to Health Related Quality of Life that we included were symptom status (presence of chronic disease or hospitalizations), functional status (developmental status), developmental aspects of the individual (social-emotional) behavior, and characteristics of the social environment (socioeconomic status and area of education). Structural equation modeling was used to assess the measurement structure of the model in 214 German children (3–5 years old) participating in a follow-up study that investigates pediatric health outcomes. Results Model fit was ?2?=?5.5; df?=?6; p?=?0.48; SRMR ?=?0.01. The variance explained of Health Related Quality of Life was 15%. Health Related Quality of Life was affected by the area education (i.e. where kindergartens were located) and development status. Developmental status was affected by the area of education, socioeconomic status and individual behavior. Symptoms did not affect the model. Conclusions The goodness of fit and the overall variance explained were good. However, the results between children' and adults' tests differed and denote a conceptual gap between adult and children measures. Indeed, there is a lot of variety in pediatric Health Related Quality of Life measures, which represents a lack of a common definition of pediatric Health Related Quality of Life. We recommend that researchers invest time in the development of pediatric Health Related Quality of Life theory and theory based evaluations. PMID:25415751

Villalonga-Olives, Ester; Kawachi, Ichiro; Almansa, Josué; Witte, Claudia; Lange, Benjamin; Kiese-Himmel, Christiane; von Steinbüchel, Nicole

2014-01-01

383

The use of structural equation modeling in generative research: Toward the design of a preventive intervention for bereaved children  

Microsoft Academic Search

Describes a generative study of processes which may lead to symptomatology in children who have experienced the death of a parent. Based on existing literature, four putative mediating variables were identified: parental demoralization, family warmth, negative family events, and positive stable family events. Structural equation modeling techniques were used to compare several potential causal models involving these variables. The results

Stephen G. West; Irwin Sandler; David R. Pillow; Louise Baca; Joanne C. Gersten

1991-01-01

384

The Best of Both Worlds: Factor Analysis of Dichotomous Data Using Item Response Theory and Structural Equation Modeling  

ERIC Educational Resources Information Center

Both structural equation modeling (SEM) and item response theory (IRT) can be used for factor analysis of dichotomous item responses. In this case, the measurement models of both approaches are formally equivalent. They were refined within and across different disciplines, and make complementary contributions to central measurement problems…

Glockner-Rist, Angelika; Hoijtink, Herbert

2003-01-01

385

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 about…

Lai, Keke; Kelley, Ken

2011-01-01

386

Data Mining in Research on Determinants of CEO Motivation: A Structural Equation Model Analysis Based on Chinese Public Companies  

Microsoft Academic Search

Data mining is an important way to discover the hidden patterns of data from a large quantity of data by precise mathematical means, which can be used for decision making in corporate governance. This research investigated determinants of CEO motivation, focusing on CEO compensation and CEO ownership. Based on a sample of 631 Chinese public companies, a structure equation model

Yue Qi; Lan Hai-lin; Jiang Luan

2008-01-01

387

Higher-Order Approximations to the Distributions of Fit Indexes under Fixed Alternatives in Structural Equation Models  

ERIC Educational Resources Information Center

Higher-order approximations to the distributions of fit indexes for structural equation models under fixed alternative hypotheses are obtained in nonnormal samples as well as normal ones. The fit indexes include the normal-theory likelihood ratio chi-square statistic for a posited model, the corresponding statistic for the baseline model of…

Ogasawara, Haruhiko

2007-01-01

388

Modeling Latent Growth Curves With Incomplete Data Using Different Types of Structural Equation Modeling and Multilevel Software  

ERIC Educational Resources Information Center

This article offers different examples of how to fit latent growth curve (LGC) models to longitudinal data using a variety of different software programs (i.e., LISREL, Mx, Mplus, AMOS, SAS). The article shows how the same model can be fitted using both structural equation modeling and multilevel software, with nearly identical results, even in…

Ferrer, Emilio; Hamagami, Fumiaki; McArdle, John J.

2004-01-01

389

Applying the Bollen-Stine Bootstrap for Goodness-of-Fit Measures to Structural Equation Models with Missing Data.  

ERIC Educational Resources Information Center

Proposed a method for extending the Bollen-Stine bootstrap model (K. Bollen and R. Stine, 1992) fit to structural equation models with missing data. Developed a Statistical Analysis System macro program to implement this procedure, and assessed its usefulness in a simulation. The new method yielded model rejection rates close to the nominal 5%…

Enders, Craig K.

2002-01-01

390

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

391

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

392

Functional and effective connectivity of visuomotor control systems demonstrated using generalized partial least squares and structural equation modeling  

Microsoft Academic Search

Tasks employing parametric variation in movement rate are associated with predictable mod- ulations in neural activity and provide a convenient context for developing new techniques for system identification. Using a multistage approach, we explored the functional and effective connectivity of a visuomotor control system by combining generalized partial least squares (gPLS) with subsequent structural equation modeling (SEM) to reveal the

Fa-Hsuan Lin; John A. Agnew; John W. Belliveau; Thomas A. Zeffiro

2009-01-01

393

Perceived Social Relationships and Science Learning Outcomes for Taiwanese Eighth Graders: Structural Equation Modeling with a Complex Sampling Consideration  

ERIC Educational Resources Information Center

Based on the Trends in International Mathematics and Science Study 2007 study and a follow-up national survey, data for 3,901 Taiwanese grade 8 students were analyzed using structural equation modeling to confirm a social-relation-based affection-driven model (SRAM). SRAM hypothesized relationships among students' perceived social relationships in…

Jen, Tsung-Hau; Lee, Che-Di; Chien, Chin-Lung; Hsu, Ying-Shao; Chen, Kuan-Ming

2013-01-01

394

Influence of a Patient Decision Aid on Decisional Conflict Related to PSA Testing: A Structural Equation Model  

Microsoft Academic Search

Objective: To examine the impact of a decision aid (DA) designed to promote informed decision making for screening with the prostate-specific antigen (PSA) test and to test a theoretical model of factors influencing decisional conflict. Design: Structural equation modeling examined pathways between DA exposure, knowledge, schema, prostate cancer risk perceptions, decisional anxiety, and decisional conflict. Sample participants included 200 men

Robert L. Stephens; Ye Xu; Robert J. Volk; Lawrence E. Scholl; Stephanie L. Kamin; E. Wayne Holden; Leonardo A. Stroud

2008-01-01

395

Socioeconomic Status and Asian American and Pacific Islander Students' Transition to College: A Structural Equation Modeling Analysis  

ERIC Educational Resources Information Center

The purpose of this study is to examine socioeconomic differences in the interpersonal factors that influence college access among Asian Americans and Pacific Islanders (AAPIs). Data on 1,460 AAPIs from the Education Longitudinal Study (ELS: 02/06) were analyzed using structural equation modeling techniques. Findings suggest that parental…

Museus, Samuel D.; Vue, Rican

2013-01-01

396

Meta-Analytic Methods of Pooling Correlation Matrices for Structural Equation Modeling under Different Patterns of Missing Data  

ERIC Educational Resources Information Center

Three methods of synthesizing correlations for meta-analytic structural equation modeling (SEM) under different degrees and mechanisms of missingness were compared for the estimation of correlation and SEM parameters and goodness-of-fit indices by using Monte Carlo simulation techniques. A revised generalized least squares (GLS) method for…

Furlow, Carolyn F.; Beretvas, S. Natasha

2005-01-01

397

An exploration of socioeconomic variation in lifestyle factors and adiposity in the Ontario Food Survey through structural equation modeling  

Microsoft Academic Search

TITLE: An exploration of socioeconomic variation in lifestyle factors and adiposity in the Ontario Food Survey through structural equation models. BACKGROUND: Socioeconomic indicators have been inversely associated with overweight and obesity, with stronger associations observed among women. The objective of the present secondary analysis was to examine the relationships among socioeconomic measures and adiposity for men and women participating in

Heather Ward; Valerie Tarasuk; Rena Mendelson; Gail McKeown-Eyssen

2007-01-01

398

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

399

Motivation for achievement as perceived resource value in social rank theory of depression: A structural equation modeling analysis  

Microsoft Academic Search

Perceived resource value reflects individual differences in motivation to acquire resource holding potential. The individualistic achievement (IA) trait, as measured by the Sociotropy Autonomy Scale, is a suitable measure for perceived resource value, and helps understand the social rank theory of depression. The present study aims to evaluate this suggestion using structural equation modeling analysis. A total of 199 university

Wai S. Tse; Jayne Wu; Kai-Chung Poon

2011-01-01

400

A theoretical model of religiosity and drug use with reciprocal relationships: A test using structural equation modeling  

Microsoft Academic Search

This study of 1093 adolescents from 6 public high schools was designed to test a hypothesized model formulated by theoretical elaboration of control theory with elements from social learning theory using structural equation modeling procedures. The primary purpose was to establish that religion is relevant to illicit drug use when its direct, indirect and reciprocal effects are tested within a

Brent B. Benda; Robert Flynn Corwyn

2000-01-01

401

Structural Equation Modeling (SEM) for Satisfaction and Dissatisfaction Ratings; Multiple Group Invariance Analysis across Scales with Different Response Format  

ERIC Educational Resources Information Center

The current study evaluates three hypothesized models on subjective well-being, comprising life domain ratings (LDR), overall satisfaction with life (OSWL), and overall dissatisfaction with life (ODWL), using structural equation modeling (SEM). A sample of 1,310 volunteering students, randomly assigned to six conditions, rated their overall life…

Mazaheri, Mehrdad; Theuns, Peter

2009-01-01

402

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), as…

Willoughby, Michael; Vandergrift, Nathan; Blair, Clancy; Granger, Douglas A.

2007-01-01

403

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

404

An Empirical Test of Tinto's Integration Framework for Community Colleges Using Structural Equation Modeling  

ERIC Educational Resources Information Center

This dissertation empirically tested Tinto's student integration theory through structural equation modeling using a national sample of 2,847 first-time entering community college students. Tinto theorized that the more academically and socially integrated a student is to the college environment, the more likely the student will persist…

Santos-George, Arlene A.

2012-01-01

405

Review of Sample Size for Structural Equation Models in Second Language Testing and Learning Research: A Monte Carlo Approach  

ERIC Educational Resources Information Center

The importance of sample size, although widely discussed in the literature on structural equation modeling (SEM), has not been widely recognized among applied SEM researchers. To narrow this gap, we focus on second language testing and learning studies and examine the following: (a) Is the sample size sufficient in terms of precision and power of…

In'nami, Yo; Koizumi, Rie

2013-01-01

406

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

407

The Preschool Behavior Questionnaire  

Microsoft Academic Search

In summary, the Preschool Behavior Questionnaire was developed as a screening instrument for use by preschool teachers, providing norms for children, ages 3–6. During the 34-month period since its publication in late 1974, the scale has been used to a considerable extent in the screening of young children. Those who have used the scale evaluate it highly. However, the variations

Lenore B. Behar

1977-01-01

408

Diet History Questionnaire  

Cancer.gov

NATIONAL INSTITUTES OF HEALTH Diet History Questionnaire Today's date: MONTH DAY YEAR |___|___| 0 0 1 1 2 2 3 3 4 5 6 7 8 01 Jan 02 Feb 03 Mar 04 Apr 05 May 06 Jun 07 Jul 08 Aug 09 Sep 10 Oct 11 Nov 12

409

Therapist Use-of-Self Orientations Questionnaire: A Reliability and Validity Study  

Microsoft Academic Search

This article describes the development of the Therapist Use-of-Self Orientation Questionnaire (TUSO-Q), an instrument designed\\u000a to measure therapists’ use-of-self orientations while working with clients. A total of 373 therapists participated in this\\u000a study. Exploratory factor analysis in the structural equation modeling context revealed three different therapist use-of-self\\u000a orientations: Transpersonal, Contextual, and Instrumental. The final model provided an excellent fit to

Stephen A. AndersonJessica; Jessica Sanderson; Iva Košuti?

410

Parallel Iterative Solution of Finite Element Systems of Equations Employing EdgeBased Data Structures \\Lambda  

E-print Network

Parallel Iterative Solution of Finite Element Systems of Equations Employing Edge­Based Data gradient solution of finite element systems of equations on unstructured grids composed by triangles or tetrahedra. The optimization techniques are based on the transition from a conventional element­by­element

Coutinho, Alvaro L. G. A.

411

NONLINEAR WAVE EQUATIONS ARISING IN MODELING OF SOME STRAIN-HARDENING STRUCTURES  

E-print Network

on a generalized Hooke's law. These equations can be used to model vibration of rods, beams, and plates made- alyzed and compared with some analytical solutions. 1 Generalized Hooke's law for Ludwick materials 1 for the material. When n = 1, equation (1) reduces to the Hooke's law for linear elastic material and the constant

Wei, Dongming

412

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

2011-09-01

413

Filipino Nursing Students' Behavioral Intentions toward Geriatric Care: A Structural Equation Model (SEM)  

ERIC Educational Resources Information Center

Anchored on the key constucts of Ajzen's Theory of Planned Behavior (1985), this paper seeks to test a model that explores the influence of knowledge, attitude, and caring behavior on nursing students' behavioral intention toward geriatric care. A five-part survey-questionnaire was administered to 839 third and fourth year nursing students from a…

de Guzman, Allan B.; Jimenez, Benito Christian B.; Jocson, Kathlyn P.; Junio, Aileen R.; Junio, Drazen E.; Jurado, Jasper Benjamin N.; Justiniano, Angela Bianca F.

2013-01-01

414

The equation of state for nucleon matter and neutron star structure  

E-print Network

Properties of dense nucleon matter and the structure of neutron stars are studied using variational chain summation methods and the new Argonne v18 two-nucleon interaction. The neutron star gravitational mass limit obtained with this interaction is 1.67 M_{solar}. Boost corrections to the two-nucleon interaction, which give the leading relativistic effect of order (v/c)^2, as well as three-nucleon interactions, are also included in the nuclear Hamiltonian. Their successive addition increases the mass limit to 1.80 and 2.20 M_{solar}. Hamiltonians including a three-nucleon interaction predict a transition in neutron star matter to a phase with neutral pion condensation at a baryon number density of 0.2 fm^{-3}. We also investigate the possibility of dense nucleon matter having an admixture of quark matter, described using the bag model equation of state. Neutron stars of 1.4 M_{solar} do not appear to have quark matter admixtures in their cores. However, the heaviest stars are predicted to have cores consisting of a quark and nucleon matter mixture. These admixtures reduce the maximum mass of neutron stars from 2.20 to 2.02 (1.91) M_{solar} for bag constant B = 200 (122) MeV/fm^3. Stars with pure quark matter in their cores are found to be unstable. We also consider the possibility that matter is maximally incompressible above an assumed density, and show that realistic models of nuclear forces limit the maximum mass of neutron stars to be below 2.5 M_{solar}. The effects of the phase transitions on the composition of neutron star matter and its adiabatic index are discussed.

A. Akmal; V. R. Pandharipande; D. G. Ravenhall

1998-04-13

415

Biomarkers and neurodevelopment in perinatally HIV-infected or exposed youth: a structural equation model analysis  

PubMed Central

Objective To examine the relationship between markers of vascular dysfunction and neurodevelopmental outcomes in perinatally HIV-infected (PHIV+) and perinatally HIV-exposed but uninfected (PHEU) youth. Design Cross-sectional design within a prospective, 15-site US-based cohort study. Methods Neurodevelopmental outcomes were evaluated in relation to nine selected vascular biomarkers in 342 youth (212 PHIV+, 130 PHEU). Serum levels were assessed for adiponectin, C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), soluble vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sE-selectin), monocyte chemoattractant protein (sMCP-1), intercellular adhesion molecule-1 (sICAM-1), and P-selectin (sP-selectin). The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) was administered at entry, yielding a Full-Scale IQ score, and four index scores. Factor analysis was conducted to reduce the biomarkers to fewer factors with related biological roles. Structural equation models (SEMs) were used to measure associations between resulting factors and WISC-IV scores. Results Mean participant age was 11.4 years, 54% were female, 70% black. The nine biomarkers were clustered into three factor groups: F1 (fibrinogen, CRP, and IL-6); F2 (sICAM-1 and sVCAM-1); and F3 (MCP-1, sP-selectin, and sE-selectin). Adiponectin showed little correlation with any factor. SEMs revealed significant negative association of F1 with WISC-IV processing speed score in the total cohort. This effect remained significant after adjusting for HIV status and other potential confounders. A similar association was observed when restricted to PHIV+ participants in both unadjusted and adjusted SEMs. Conclusion Aggregate measures of fibrinogen, CRP, and IL-6 may serve as a latent biomarker associated with relatively decreased processing speed in both PHIV+ and PHEU youth. PMID:24670521

Kapetanovic, Suad; Griner, Ray; Zeldow, Bret; Nichols, Sharon; Leister, Erin; Gelbard, Harris A.; Miller, Tracie L.; Hazra, Rohan; Mendez, Armando J.; Malee, Kathleen; Kammerer, Betsy; Williams, Paige L.

2014-01-01

416

Determinants of work injuries in mines - an application of structural equation modelling.  

PubMed

In spite of stringent regulations and much attention towards reducing risks in the physical environment, the mining industry continues to be associated with high levels of accidents, injuries and illnesses. Only engineering solutions to accident prevention are inappropriate unless coupled with focused attention to the attitudes and behaviours of the mineworkers in coping with the inherent physical, technical and situational risks. The present study identified these various risk factors and analysed their influences on work injury in a causal framework. Data were collected from an underground coalmine of India. The pattern and strength of relationships of 16 causal factors with work injuries were assessed through structural equation modelling. The case study results showed that negatively personified individuals are of major concern for safety improvement in the mine studied. They not only fail to avoid work injuries, they are unable to extend safe work behaviours in their work. The variable safety environment is negatively affected by personality, whereas social support has a positive relationship with safety environment. The variable job hazards appeared to have a significant relationship with job involvement, which has a negative relationship with work injury. Elimination of negative behaviours must be focused and committed by the mine safety management. Long term planning through (i) identification of negative individuals, (ii) proper councelling of adverse effects of negative behaviours, and (iii) special training with psychological treatment is highly required. Identification may begin while recruiting new workers through interview. Proper allocation of jobs (right person for right job) may be a judicial solution to this end. PMID:14977503

Maiti, J; Chatterjee, S; Bangdiwala, S I

2004-03-01

417

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

2013-01-01

418

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. PMID:24086670

Slocum, Matthew G.; Orzell, Steve L.

2013-01-01

419

A structural equation model analysis of postfire plant diversity in California shrublands  

USGS Publications Warehouse

This study investigates patterns of plant diversity following wildfires in fire-prone shrublands of California, seeks to understand those patterns in terms of both local and landscape factors, and considers the implications for fire management. Ninety study sites were established following extensive wildfires in 1993, and 1000-m2 plots were used to sample a variety of parameters. Data on community responses were collected for five years following fire. Structural equation modeling (SEM) was used to relate plant species richness to plant abundance, fire severity, abiotic conditions, within-plot heterogeneity, stand age, and position in the landscape. Temporal dynamics of average richness response was also modeled. Richness was highest in the first year following fire, indicating postfire enhancement of diversity. A general decline in richness over time was detected, with year-to-year variation attributable to annual variations in precipitation. Peak richness in the landscape was found where (1) plant abundance was moderately high, (2) within-plot heterogeneity was high, (3) soils were moderately low in nitrogen, high in sand content, and with high rock cover, (4) fire severity was low, and (5) stands were young prior to fire. Many of these characteristics were correlated with position in the landscape and associated conditions. We infer from the SEM results that postfire richness in this system is strongly influenced by local conditions and that these conditions are, in turn, predictably related to landscape-level conditions. For example, we observed that older stands of shrubs were characterized by more severe fires, which were associated with a low recovery of plant cover and low richness. These results may have implications for the use of prescribed fire in this system if these findings extrapolate to prescribed burns as we would expect. ?? 2006 by the Ecological Society of America.

Grace, J. B.; Keeley, J. E.

2006-01-01

420

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

421

The Structure of Killing Spinor Equation (Heterotic) M-theory on Seven Manifolds with Fluxes  

Microsoft Academic Search

Recently much attention have been paid to compactifications of M-theory and string theory with fluxes turned on. In this paper we study the Killing spinor equations of M-theory and Heterotic M-theory on seven dimensional Riemannian manifolds with fluxes turned on. We derive the conditions on the geometry that follow from the integrability conditions of the Killing spinor equations. We then

Tibra Ali; Gerald Cleaver; John Perkins

2004-01-01

422

Numerical Simulation of Fluid-Structure Interaction Using Modified Ghost Fluid Method and Naviers Equations  

Microsoft Academic Search

In this work, we deal with the 1D compressible fluid coupled with elastic solid in an Eulerian-Lagrangian system. To facilitate\\u000a the analysis, the Naviers equation for elastic solid is cast into a 2×2 system similar to the Euler equation but in Lagrangian\\u000a coordinate. The modified Ghost Fluid Method is employed to treat the fluid-elastic solid coupling, where an Eulerian-Lagrangian\\u000a Riemann

T. G. Liu; J. Y. Ho; B. C. Khoo; A. W. Chowdhury

2008-01-01

423

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

424

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

425

The Toronto Empathy Questionnaire  

PubMed Central

In order to formulate a parsimonious tool to assess empathy, we used factor analysis on a combination of self-report measures to examine consensus and developed a brief self-report measure of this common factor. The Toronto Empathy Questionnaire (TEQ) represents empathy as a primarily emotional process. In three studies, the TEQ demonstrated strong convergent validity, correlating positively with behavioral measures of social decoding, self-report measures of empathy, and negatively with a measure of Autism symptomatology. Moreover, it exhibited good internal consistency and high test-retest reliability. The TEQ is a brief, reliable, and valid instrument for the assessment of empathy. PMID:19085285

Spreng, R. Nathan; McKinnon, Margaret C.; Mar, Raymond A.; Levine, Brian

2008-01-01

426

Ab initio Equation of State data for hydrogen, helium, and water and the internal structure of Jupiter  

E-print Network

The equation of state of hydrogen, helium, and water effects interior structure models of giant planets significantly. We present a new equation of state data table, LM-REOS, generated by large scale quantum molecular dynamics simulations for hydrogen, helium, and water in the warm dense matter regime, i.e.for megabar pressures and temperatures of several thousand Kelvin, and by advanced chemical methods in the complementary regions. The influence of LM-REOS on the structure of Jupiter is investigated and compared with state-of-the-art results within a standard three-layer model consistent with astrophysical observations of Jupiter. Our new Jupiter models predict an important impact of mixing effects of helium in hydrogen with respect to an altered compressibility and immiscibility.

N. Nettelmann; B. Holst; A. Kietzmann; M. French; R. Redmer; D. Blaschke

2007-12-06

427

Quality of Adult Child-Aging Parent Relationships: A Structural Equations Approach Using Merged Cross-Generational Data  

Microsoft Academic Search

In a study of the attachment bond, determinants of the quality of the adult child-aging parent relationship are analyzed from the child's perspective for 180 adult child-aging parent pairs. Structural equation models are estimated for thefull sample andfor parent-child pairs living more than 60 miles apart and within 60 miles of each other. In the full sample, quality of the

Joyce McDonough Mercier; Mack C. Shelley; Bing Wall

1997-01-01

428

The Relationship Among Central Obesity, Systemic Inflammation, and Left Ventricular Diastolic Dysfunction as Determined by Structural Equation Modeling  

Microsoft Academic Search

The purpose of this study was to investigate the associations among central obesity, inflammation, and left ventricular (LV) diastolic dysfunction by structural equation modeling. Echocardiographic parameters were assessed in 102 otherwise-healthy adults over age 30. The participants were classified as having LV diastolic dysfunction by echocardiographic findings including mitral inflow E\\/A ratio 220 cm\\/s, or decreased peak annular early diastolic

Cho-Kai Wu; Chung-Yi Yang; Jou-Wei Lin; Hung-Jen Hsieh; Fu-Chun Chiu; Jen-Junn Chen; Jen-Kuang Lee; Shu-Wei Huang; Hung-Yuan Li; Fu-Tien Chiang; Jin-Jer Chen; Chia-Ti Tsai

2012-01-01

429

Neurological Soft Signs and Their Relationships to Neurocognitive Functions: A ReVisit with the Structural Equation Modeling Design  

Microsoft Academic Search

BackgroundNeurological soft signs and neurocognitive impairments have long been considered important features of schizophrenia. Previous correlational studies have suggested that there is a significant relationship between neurological soft signs and neurocognitive functions. The purpose of the current study was to examine the underlying relationships between these two distinct constructs with structural equation modeling (SEM).Methods118 patients with schizophrenia and 160 healthy

Raymond C. K. Chan; Ya Wang; Li Wang; Eric Y. H. Chen; Theo C. Manschreck; Zhan-Jiang Li; Xin Yu; Qi-Yong Gong; Jeremy Miles

2009-01-01

430

Structural equation socialization model of substance use among Mexican-American and white non-Hispanic school dropouts  

Microsoft Academic Search

Purpose: To test a socialization model of polydrug use among Mexican-American and white non-Hispanic school dropouts.Methods: A sample of 910 Mexican-American and white non-Hispanic school dropouts were surveyed regarding their use of alcohol, marijuana, and other drugs, and socialization characteristics that have previously been shown to be predictive of adolescent substance use. A structural equation model based on peer cluster

RandallC Swaim; ScottC Bates; ErnestL Chavez

1998-01-01

431

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

432

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

433

Developing Written Questionnaires: Determining if Questionnaires Should be Used  

NSDL National Science Digital Library

This module provides a strategy for determining whether a written questionnaire is an appropriate means of gathering data to meet the goals of an evaluation. The authors define which conditions are suitable for using questionnaires.

Zalles, Daniel R.; Library, Online E.

434

Kinetic Equation with Electromagnetic Interactions.  

National Technical Information Service (NTIS)

A kinetic equation for a plasma with electromagnetic interactions is derived in the shielding approximation. The equation is the analog of the Landau equation and has the same structure as the Landau equation but with a velocity dependent interaction repl...

J. T. Hogan, M. B. Lewis

1967-01-01

435

Attractors and their structure for semilinear wave equations with nonlinear boundary dissipation  

Microsoft Academic Search

Long time behavior of a semilinear wave equation with nonlinear boundary dissipation is considered. It is shown that weak solutions generated by the wave dynamics converge asymptotically to a flnite dimensional attractor. It is known (CEL1) that the attractor consists of all full trajectories emanating from the set of stationary points. Under the additional assumption that the set of stationary

Igor Chueshov; Matthias Eller; Irena Lasiecka

2004-01-01

436

LINKING URBAN FORESTS AND URBAN TOURISM: A STRUCTURAL EQUATION MODELING APPROACH  

Microsoft Academic Search

Urban forests play an essential part in enhancing a city's image, attracting tourists, and increasing tourism experiences. However, few studies have been conducted to examine the linkage between urban forests and urban tourism. This paper for the first time develops and tests a structual equation model that links tourists' perceptions of urban forests, city beaufication, tourism experiences, tourism satisfaction, and

Jinyang Deng; Kathryn G. Arano

437

Hints for Designing Effective Questionnaires  

NSDL National Science Digital Library

The purpose of this article is to offer tips in designing quality questionnaires and on avoiding common errors. Some of the more prevalent problems in questionnaire development are identified and suggestions of ways to avoid them are offered.

Frary, Robert

438

Guides & Reports for Questionnaire Design  

Cancer.gov

Applied Research Program (ARP) staff use a variety of methods to develop and test questionnaires, including established Questionnaire Design Principles, empirical methods such as Cognitive Testing and psychometric methods such as Item Response Theory Modeling.

439

ATBC Study - Questionnaires and Forms  

Cancer.gov

Skip to Main Content Home Contact Us Links Study Details Questionnaires & Forms Current Projects ATBC Study Bibliography Study Investigators & Collaborators Proposal Review & Collaboration Research Consortium Projects Questionnaires & Forms Baseline

440

Diet History Questionnaire: International Applications  

Cancer.gov

ARP staff adapted the Diet History Questionnaire (DHQ) for use by Canadian populations in collaboration with the Alberta Cancer Board. This questionnaire takes into account the different food fortification polices of the US and Canada.

441

Survey and Questionnaire Tutorial  

NSDL National Science Digital Library

What are the important factors to consider when designing a survey? Would it be best conducted via telephone? Or would it be better to have a face-to-face meeting? These are but a few of the topics covered on this site created as a public service by the StatPac group. Visitors can elect to download the entire report on survey design here, or they can just click through the topics that interest them. Each topic includes a brief discussion of its relative importance, and the areas covered include questionnaire length, time considerations, question wording, and sampling methods. It's a thoughtful and helpful resource overall, and it's one that might be put to good use in an introductory statistics course in college.

442

School of Informatics Course Questionnaire  

E-print Network

School of Informatics Course Questionnaire The School of Informatics welcomes constructive comments Organisation office on Appleton Tower level 4. If you prefer, you can also complete this questionnaire online: http://www.inf.ed.ac.uk/admin/ITO/questionnaires You can also provide feedback directly to your

Koehn, Philipp

443

Electron structure, Zitterbewegung, and the new non-linear Dirac-like equation  

E-print Network

The recent literature shows a renewed interest, with various independent approaches, in the classical theories for spin. Considering the possible interest of those results, at least for the electron case, we purpose in this paper to explore their physical and mathematical meaning, by the natural and powerful language of Clifford algebras (which, incidentally, will allow us to unify those different approaches). In such theories, the ordinary electron is in general associated to the mean motion of a point-like "constituent" Q, whose trajectory is a cylindrical helix. We find, in particular, that the object Q obeys a new, non-linear Dirac-like equation, such that --when averaging over an internal cycle (which corresponds to linearization)-- it transforms into the ordinary Dirac equation (valid for the electron as a whole).

M. Pavsic; Erasmo Recami; W. A. Rodrigues Jr

1998-03-14

444

Causal structure of oscillations in gene regulatory networks: Boolean analysis of ordinary differential equation attractors.  

PubMed

A common approach to the modeling of gene regulatory networks is to represent activating or repressing interactions using ordinary differential equations for target gene concentrations that include Hill function dependences on regulator gene concentrations. An alternative formulation represents the same interactions using Boolean logic with time delays associated with each network link. We consider the attractors that emerge from the two types of models in the case of a simple but nontrivial network: a figure-8 network with one positive and one negative feedback loop. We show that the different modeling approaches give rise to the same qualitative set of attractors with the exception of a possible fixed point in the ordinary differential equation model in which concentrations sit at intermediate values. The properties of the attractors are most easily understood from the Boolean perspective, suggesting that time-delay Boolean modeling is a useful tool for understanding the logic of regulatory networks. PMID:23822502

Sun, Mengyang; Cheng, Xianrui; Socolar, Joshua E S

2013-06-01

445

Analysis of the bulk and surface-induced structure of electrolyte solutions using integral equation theories  

SciTech Connect

We have developed robust and efficient numerical methods for solving integral equation theories for electrolyte solutions. These methods are hybrids of Newton-Raphson and Picard iterations and have been obtained as extended versions of the previous methods for pure solvents by solving nontrivial problems posed by the inclusion of ions. Bulk electrolytes and electrolytes near both inert and metallic surfaces are considered. The basic equations previously derived for a one-component fluid near a planar wall are extended to a multicomponent fluid. Analytical expressions for elements of the Jacobian matrices are arranged in compact form. A striking feature of the method for surface problems is that the Jacobian is determined only from bulk properties. A discussion of some special treatments that need to be considered for asymmetric anions and cations is included. These methods have been demonstrated using the full reference hypernetted-chain theory for various sizes of ions in a wide range of ionic concentrations. 19 refs., 3 tabs.

Kinoshita, M.; Berard, D.R. [Univ. of British Columbia, Vancouver (Canada)] [Univ. of British Columbia, Vancouver (Canada)

1996-03-01

446

The Hamiltonian structure of Dirac's equation in tensor form and its Fermi quantization  

NASA Technical Reports Server (NTRS)

Currently, there is some interest in studying the tensor forms of the Dirac equation to elucidate the possibility of the constrained tensor fields admitting Fermi quantization. We demonstrate that the bispinor and tensor Hamiltonian systems have equivalent Fermi quantizations. Although the tensor Hamiltonian system is noncanonical, representing the tensor Poisson brackets as commutators for the Heisenberg operators directly leads to Fermi quantization without the use of bispinors.

Reifler, Frank; Morris, Randall

1992-01-01

447

Thermodynamic structure of field equations near apparent horizon for radiating black holes  

E-print Network

We study the intriguing analogy between gravitational dynamics of the horizon and thermodynamics for the case of nonstationary radiating spherically symmetric black holes both in four dimensions and higher dimensions. By defining all kinematical parameters of nonstationary radiating black holes in terms of null vectors, we demonstrate that it is possible to interpret the Einstein field equations near the apparent horizon in the form of a thermodynamical identity $TdS=dE+PdV$.

Papnoi, Uma; Ghosh, Sushant G

2014-01-01

448

Thermodynamic structure of field equations near apparent horizon for radiating black holes  

E-print Network

We study the intriguing analogy between gravitational dynamics of the horizon and thermodynamics for the case of nonstationary radiating spherically symmetric black holes both in four dimensions and higher dimensions. By defining all kinematical parameters of nonstationary radiating black holes in terms of null vectors, we demonstrate that it is possible to interpret the Einstein field equations near the apparent horizon in the form of a thermodynamical identity $TdS=dE+PdV$.

Uma Papnoi; Megan Govender; Sushant G Ghosh

2014-11-10

449

Static aeroelastic analysis of wings using Euler/Navier-Stokes equations coupled with improved wing-box finite element structures  

NASA Technical Reports Server (NTRS)

Strong interactions between flow about an aircraft wing and the wing structure can result in aeroelastic phenomena which significantly impact aircraft performance. Time-accurate methods for solving the unsteady Navier-Stokes equations have matured to the point where reliable results can be obtained with reasonable computational costs for complex non-linear flows with shock waves, vortices and separations. The ability to combine such a flow solver with a general finite element structural model is key to an aeroelastic analysis in these flows. Earlier work involved time-accurate integration of modal structural models based on plate elements. A finite element model was developed to handle three-dimensional wing boxes, and incorporated into the flow solver without the need for modal analysis. Static condensation is performed on the structural model to reduce the structural degrees of freedom for the aeroelastic analysis. Direct incorporation of the finite element wing-box structural model with the flow solver requires finding adequate methods for transferring aerodynamic pressures to the structural grid and returning deflections to the aerodynamic grid. Several schemes were explored for handling the grid-to-grid transfer of information. The complex, built-up nature of the wing-box complicated this transfer. Aeroelastic calculations for a sample wing in transonic flow comparing various simple transfer schemes are presented and discussed.

Guruswamy, Guru P.; MacMurdy, Dale E.; Kapania, Rakesh K.

1994-01-01

450

Psychometric Evaluation of the Chinese Virtues Questionnaire  

ERIC Educational Resources Information Center

Objectives: The present study examined the psychometric properties of the Chinese Virtues Questionnaire (CVQ). The reliability, factor structure, construct validity, and temporal stability of the inventory were examined. Method: A university student sample ("n" = 878) and a working adult sample ("n" = 153) were recruited.…

Duan, Wenjie; Ho, Samuel M. Y.; Bai, Yu; Tang, Xiaoqing

2013-01-01

451

Full equations utilities (FEQUTL) model for the approximation of hydraulic characteristics of open channels and control structures during unsteady flow  

USGS Publications Warehouse

The Full EQuations UTiLities (FEQUTL) model is a computer program for computation of tables that list the hydraulic characteristics of open channels and control structures as a function of upstream and downstream depths; these tables facilitate the simulation of unsteady flow in a stream system with the Full Equations (FEQ) model. Simulation of unsteady flow requires many iterations for each time period computed. Thus, computation of hydraulic characteristics during the simulations is impractical, and preparation of function tables and application of table look-up procedures facilitates simulation of unsteady flow. Three general types of function tables are computed: one-dimensional tables that relate hydraulic characteristics to upstream flow depth, two-dimensional tables that relate flow through control structures to upstream and downstream flow depth, and three-dimensional tables that relate flow through gated structures to upstream and downstream flow depth and gate setting. For open-channel reaches, six types of one-dimensional function tables contain different combinations of the top width of flow, area, first moment of area with respect to the water surface, conveyance, flux coefficients, and correction coefficients for channel curvilinearity. For hydraulic control structures, one type of one-dimensional function table contains relations between flow and upstream depth, and two types of two-dimensional function tables contain relations among flow and upstream and downstream flow depths. For hydraulic control structures with gates, a three-dimensional function table lists the system of two-dimensional tables that contain the relations among flow and upstream and downstream flow depths that correspond to different gate openings. Hydraulic control structures for which function tables containing flow relations are prepared in FEQUTL include expansions, contractions, bridges, culverts, embankments, weirs, closed conduits (circular, rectangular, and pipe-arch shapes), dam failures, floodways, and underflow gates (sluice and tainter gates). The theory for computation of the hydraulic characteristics is presented for open channels and for each hydraulic control structure. For the hydraulic control structures, the theory is developed from the results of experimental tests of flow through the structure for different upstream and downstream flow depths. These tests were done to describe flow hydraulics for a single, steady-flow design condition and, thus, do not provide complete information on flow transitions (for example, between free- and submerged-weir flow) that may result in simulation of unsteady flow. Therefore, new procedures are developed to approximate the hydraulics of flow transitions for culverts, embankments, weirs, and underflow gates.

Franz, Delbert D.; Melching, Charles S.

1997-01-01

452

The Attitudes to Ageing Questionnaire: Mokken Scaling Analysis  

PubMed Central

Background Hierarchical scales are useful in understanding the structure of underlying latent traits in many questionnaires. The Attitudes to Ageing Questionnaire (AAQ) explored the attitudes to ageing of older people themselves, and originally described three distinct subscales: (1) Psychosocial Loss (2) Physical Change and (3) Psychological Growth. This study aimed to use Mokken analysis, a method of Item Response Theory, to test for hierarchies within the AAQ and to explore how these relate to underlying latent traits. Methods Participants in a longitudinal cohort study, the Lothian Birth Cohort 1936, completed a cross-sectional postal survey. Data from 802 participants were analysed using Mokken Scaling analysis. These results were compared with factor analysis using exploratory structural equation modelling. Results Participants were 51.6% male, mean age 74.0 years (SD 0.28). Three scales were identified from 18 of the 24 items: two weak Mokken scales and one moderate Mokken scale. (1) ‘Vitality’ contained a combination of items from all three previously determined factors of the AAQ, with a hierarchy from physical to psychosocial; (2) ‘Legacy’ contained items exclusively from the Psychological Growth scale, with a hierarchy from individual contributions to passing things on; (3) ‘Exclusion’ contained items from the Psychosocial Loss scale, with a hierarchy from general to specific instances. All of the scales were reliable and statistically significant with ‘Legacy’ showing invariant item ordering. The scales correlate as expected with personality, anxiety and depression. Exploratory SEM mostly confirmed the original factor structure. Conclusions The concurrent use of factor analysis and Mokken scaling provides additional information about the AAQ. The previously-described factor structure is mostly confirmed. Mokken scaling identifies a new factor relating to vitality, and a hierarchy of responses within three separate scales, referring to vitality, legacy and exclusion. This shows what older people themselves consider important regarding their own ageing. PMID:24892302

Shenkin, Susan D.; Watson, Roger; Laidlaw, Ken; Starr, John M.; Deary, Ian J.

2014-01-01

453

DISABILITY QUESTIONNAIRE This questionnaire MUST be completed by the STUDENT.  

E-print Network

1 DISABILITY QUESTIONNAIRE This questionnaire MUST be completed by the STUDENT. Name: Date: Phone) Other: 7. Check any of the following campus resources you have used: Psychological Services Math Center/Drug Rehabilitation In-patient/Out-patient Psychiatric Care Private Counseling/Psychological Services Optometric

Gallo, Linda C.

454

Structural equation modeling and nested ANOVA: Effects of lead exposure on maternal and fetal growth in rats  

SciTech Connect

This study provided an assessment of the effects of lead on early growth in rats based on structural equation modeling and nested analysis of variance (ANOVA). Structural equation modeling showed that lead in drinking water (250, 500, or 1000 ppm) had a direct negative effect on body weight and tail length (i.e., growth) in female rats during the first week of exposure. During the following 2 weeks of exposure, high correlation between growth measurements taken over time resulted in reduced early postnatal growth. By the fourth week of exposure, reduced growth was not evident. Mating began after 8 weeks of exposure, and exposure continued during gestation. Decreased fetal body weight was detected when the effects of litter size, intrauterine position, and sex were controlled in a nested ANOVA. Lead exposure did not appear to affect fetal skeletal development, possibly because lead did not alter maternal serum calcium and phosphorus levels. The effect of lead on individual fetal body weight suggests that additional studies are needed to examine the effect of maternal lead exposure on fetal development and early postnatal growth. 24 refs., 4 figs., 6 tabs.

Hamilton, J.D. (Rohm and Haas Company, Spring House, PA (United States)); O'Flaherty, E.J.; Shukla, R.; Gartside, P.S. (Univ. of Cincinnati, OH (United States)); Ross, R. (Univ. of Cincinnati Medical Center, Cincinnati, OH (United States))

1994-01-01

455

Multidisciplinary Treatment Planning Questionnaire  

Cancer.gov

Multidisciplinary care, which incorporates Multidisciplinary Treatment Planning (MTP), is increasingly being adopted within oncology care settings with the intent of enhancing the quality of care delivered to patients. However, what is not known is its impact on improving patient outcomes and the quality of care being delivered. A targeted review of the literature was conducted to examine the organization and operation of the Multidisciplinary Care (MDC) team structure1. Findings revealed that a variety of implementation models exist within the health care system.

456

Conservation of integrals and symplectic structure in the integration of differential equations by multistep methods  

Microsoft Academic Search

Summary We consider the question of whether multistep methods inherit in some sense quadratic first integrals possessed by the differential system being integrated. We also investigate whether, in the integration of Hamiltonian systems, multistep methods conserve the symplectic structure of the phase space.

T. Eirola; J. M. Sanz-Serna

1992-01-01

457

What Influences Geography Teachers' Usage of Geographic Information Systems? A Structural Equation Analysis  

ERIC Educational Resources Information Center

Understanding the usage of the geographic information system (GIS) among geography teachers is a crucial step in evaluating the current dissemination of GIS knowledge and skills in Taiwan's educational system. The primary contribution of this research is to further our understanding of the factors that affect teachers' GIS usage. The structural…

Lay, Jinn-Guey; Chi, Yu-Lin; Hsieh, Yeu-Sheng; Chen, Yu-Wen

2013-01-01

458

What Influences Eighth-Grade Hispanic Students' Academic Achievement? A Structural Equation Analysis.  

ERIC Educational Resources Information Center

A structural model of school learning was tested to examine both direct and indirect influences of previous grades, quality of instruction, motivation, quantity of instruction, and homework on Hispanic-American eighth-grade students' academic achievement, while controlling for background variables. The model was analyzed with path analytic…

Hernandez-Gantes, Victor M.

459

ORIGINAL PAPER Equation of state and pressure-induced structural changes  

E-print Network

-pressure phase of mirabi- lite, parameterised by fitting an integrated form of the third-order Birch the bulk elastic properties of mirabilite, Na2SO4Á10H2O, and to obtain information on structural trends with an equilibrium mixture of Na2SO4 and H2O at room temperature and pressure; the synthetic substance is referred

Vocadlo, Lidunka

460

Development of Wing Structural Weight Equation for Active Aeroelastic Wing Technology  

Microsoft Academic Search

A multidisciplinary design study considering the impact of Active Aeroelastic Wing (AAW) technology on the structural wing weight of a lightweight fighter concept is presented. The study incorporates multidisciplinary design optimization (MDO) and response surface methods to characterize wing weight as a function of wing geometry. The study involves the sizing of the wing box skins of several fighter configurations

P. Scott Zink; Dimitri N. Mavris; Peter M. Flick; Michael H. Love

1999-01-01

461

The Robustness of LISREL Estimates in Structural Equation Models with Categorical Variables.  

ERIC Educational Resources Information Center

This study examined the effect of type of correlation matrix on the robustness of LISREL maximum likelihood and unweighted least squares structural parameter estimates for models with categorical variables. The analysis of mixed matrices produced estimates that closely approximated the model parameters except where dichotomous variables were…

Ethington, Corinna A.

1987-01-01

462

The Robustness of LISREL Estimates in Structural Equation Models with Categorical Variables.  

ERIC Educational Resources Information Center

This study examined the effect of type of correlation matrix on the robustness of LISREL maximum likelihood and unweighted least squares structural parameter estimates for models with categorical manifest variables. Two types of correlation matrices were analyzed; one containing Pearson product-moment correlations and one containing tetrachoric,…

Ethington, Corinna A.

463

Variance Estimation Using Replication Methods in Structural Equation Modeling with Complex Sample Data  

ERIC Educational Resources Information Center

This article discusses replication sampling variance estimation techniques that are often applied in analyses using data from complex sampling designs: jackknife repeated replication, balanced repeated replication, and bootstrapping. These techniques are used with traditional analyses such as regression, but are currently not used with structural…

Stapleton, Laura M.

2008-01-01

464

JOB EVALUATION QUESTIONNAIRE ANSWER SHEET  

E-print Network

JOB EVALUATION QUESTIONNAIRE ANSWER SHEET DO NOT WRITE IN THIS SPACE N.C. Date Received Reclass New Starting Date in Class Yes No NA (NA if Temporary Job) Notice # Effective Date If Reclassified IS TO BE USED WITH THE JOB EVALUATION QUESTIONNAIRE (BA 802) ONLY FOR POSITIONS COVERED BY CIVIL SERVICE

Amin, S. Massoud

465

School Integration Questionnaire for Parents.  

ERIC Educational Resources Information Center

This 40-item questionnaire intends to measure parent opinion on the effects of integration on their children and the school system. A recommended letter to parents is included. No field testing has been done. (See also TM 000 940 for a description of the study and 941, 942 for other questionnaires used.) (DLG)

Goolsby, Thomas M., Jr.; And Others

466

ASSESSMENT Cepeda-Benito 10.1177/1073191103261410 ARTICLE et al. / F ACTOR STRUCTURE EXAMINATION OF CRAVINGS TO SMOKE Cross-Cultural Investigation of the Questionnaire of Smoking Urges in American and Spanish Smokers  

E-print Network

This study evaluated the factor structure of the Questionnaire of Smoking Urges (QSU) across American and Spanish smokers. Using confirmatory factor analyses, the fits of one-, two-, and four-factor models of smoking craving in American and Spanish data sets were compared. The two-factor model provided the best fit in both samples. However, negatively worded items confounded the interpretation of the two-factor structure in both the American and Spanish data. The first factor had positively and negatively worded items, whereas the second had only positively worded items. The two-factor structure was reexamined, removing either the positively or the negatively worded items. Using only positively worded items resulted in a loss of fit, whereas using only negatively worded items improved model fit substantially. Thus, the results supported the generalization of smoking craving across Spanish and American smokers and suggested that negatively worded items play a larger role in the two-factor structure of the QSU than originally thought. Keywords: smoking; urges; cravings; drug addiction; Hispanic Drug cravings are subjective motivational states

Antonio Cepeda-benito; Keisha Henry; David H. Gleaves; Mari Carmen Fernandez

467

Querying databases of trajectories of differential equations: Data structures for trajectories  

NASA Technical Reports Server (NTRS)

One approach to qualitative reasoning about dynamical systems is to extract qualitative information by searching or making queries on databases containing very large numbers of trajectories. The efficiency of such queries depends crucially upon finding an appropriate data structure for trajectories of dynamical systems. Suppose that a large number of parameterized trajectories gamma of a dynamical system evolving in R sup N are stored in a database. Let Eta is contained in set R sup N denote a parameterized path in Euclidean Space, and let the Euclidean Norm denote a norm on the space of paths. A data structure is defined to represent trajectories of dynamical systems, and an algorithm is sketched which answers queries.

Grossman, Robert

1989-01-01

468

Hamiltonian structure of an operator valued extension of Super KdV equations  

NASA Astrophysics Data System (ADS)

An extension of the super Korteweg-de Vries integrable system in terms of operator valued functions is obtained. In particular the extension contains the N = 1 Super KdV and coupled systems with functions valued on a symplectic space. We introduce a Miura transformation for the extended system and obtain its hamiltonian structure. We also obtain an extended Gardner transformation which allows to find an infinite number of conserved quantities of the extended system.

Restuccia, Alvaro; Sotomayor, Adrián

2013-11-01

469

Multi-Center Electronic Structure Calculations for Plasma Equation of State  

SciTech Connect

We report on an approach for computing electronic structure utilizing solid-state multi-center scattering techniques, but generalized to finite temperatures to model plasmas. This approach has the advantage of handling mixtures at a fundamental level without the imposition of ad hoc continuum lowering models, and incorporates bonding and charge exchange, as well as multi-center effects in the calculation of the continuum density of states.

Wilson, B G; Johnson, D D; Alam, A

2010-12-14

470

Inverse Material Identification in Coupled Acoustic-Structure Interaction using a Modified Error in Constitutive Equation Functional  

PubMed Central

This work focuses on the identification of heterogeneous linear elastic moduli in the context of frequency-domain, coupled acoustic-structure interaction (ASI), using either solid displacement or fluid pressure measurement data. The approach postulates the inverse problem as an optimization problem where the solution is obtained by minimizing a modified error in constitutive equation (MECE) functional. The latter measures the discrepancy in the constitutive equations that connect kinematically admissible strains and dynamically admissible stresses, while incorporating the measurement data as additional quadratic error terms. We demonstrate two strategies for selecting the MECE weighting coefficient to produce regularized solutions to the ill-posed identification problem: 1) the discrepancy principle of Morozov, and 2) an error-balance approach that selects the weight parameter as the minimizer of another functional involving the ECE and the data misfit. Numerical results demonstrate that the proposed methodology can successfully recover elastic parameters in 2D and 3D ASI systems from response measurements taken in either the solid or fluid subdomains. Furthermore, both regularization strategies are shown to produce accurate reconstructions when the measurement data is polluted with noise. The discrepancy principle is shown to produce nearly optimal solutions, while the error-balance approach, although not optimal, remains effective and does not need a priori information on the noise level. PMID:25339790

Warner, James E.; Diaz, Manuel I.; Aquino, Wilkins; Bonnet, Marc

2014-01-01

471

Inverse material identification in coupled acoustic-structure interaction using a modified error in constitutive equation functional  

NASA Astrophysics Data System (ADS)

This work focuses on the identification of heterogeneous linear elastic moduli in the context of frequency-domain, coupled acoustic-structure interaction (ASI), using either solid displacement or fluid pressure measurement data. The approach postulates the inverse problem as an optimization problem where the solution is obtained by minimizing a modified error in constitutive equation (MECE) functional. The latter measures the discrepancy in the constitutive equations that connect kinematically admissible strains and dynamically admissible stresses, while incorporating the measurement data as additional quadratic error terms. We demonstrate two strategies for selecting the MECE weighting coefficient to produce regularized solutions to the ill-posed identification problem: 1) the discrepancy principle of Morozov, and 2) an error-balance approach that selects the weight parameter as the minimizer of another functional involving the ECE and the data misfit. Numerical results demonstrate that the proposed methodology can successfully recover elastic parameters in 2D and 3D ASI systems from response measurements taken in either the solid or fluid subdomains. Furthermore, both regularization strategies are shown to produce accurate reconstructions when the measurement data is polluted with noise. The discrepancy principle is shown to produce nearly optimal solutions, while the error-balance approach, although not optimal, remains effective and does not need a priori information on the noise level.

Warner, James E.; Diaz, Manuel I.; Aquino, Wilkins; Bonnet, Marc

2014-09-01

472

The consequences of ignoring measurement invariance for path coefficients in structural equation models  

PubMed Central

We report a Monte Carlo study examining the effects of two strategies for handling measurement non-invariance – modeling and ignoring non-invariant items – on structural regression coefficients between latent variables measured with item response theory models for categorical indicators. These strategies were examined across four levels and three types of non-invariance – non-invariant loadings, non-invariant thresholds, and combined non-invariance on loadings and thresholds – in simple, partial, mediated and moderated regression models where the non-invariant latent variable occupied predictor, mediator, and criterion positions in the structural regression models. When non-invariance is ignored in the latent predictor, the focal group regression parameters are biased in the opposite direction to the difference in loadings and thresholds relative to the referent group (i.e., lower loadings and thresholds for the focal group lead to overestimated regression parameters). With criterion non-invariance, the focal group regression parameters are biased in the same direction as the difference in loadings and thresholds relative to the referent group. While unacceptable levels of parameter bias were confined to the focal group, bias occurred at considerably lower levels of ignored non-invariance than was previously recognized in referent and focal groups.

Guenole, Nigel; Brown, Anna

2014-01-01

473

Gender differences in the psychosocial and cognitive correlates of physical activity among Taiwanese adolescents: a structural equation modeling approach.  

PubMed

This study examined gender differences in the factors related to physical activity in 832 Taiwanese adolescents. Differences in psychosocial and cognitive correlates were noted by gender group. Taiwanese adolescent girls reported lower physical activity self-efficacy and less perceived benefits and more perceived barriers to being active than boys. Girls compared to boys reported significantly more positive social support, modeling, and norms from parents to be active but significantly less social support and norms from their peers. Structural equation modeling was used to test the direct and indirect paths of a model of proposed correlates and physical activity. The results indicated that peer influences had both direct and indirect paths to physical activity for both genders. Among all examined variables, perceived self-efficacy was the strongest correlate of physical activity for these adolescents. The findings of this study provide information relevant to designing physical activity interventions targeted to Taiwanese adolescents. PMID:12763704

Wu, Su-Yin; Pender, Nola; Noureddine, Samar

2003-01-01

474

Periodic structures in the Franck-Hertz experiment with neon: Boltzmann equation and Monte-Carlo analysis  

NASA Astrophysics Data System (ADS)

The Franck-Hertz experiment with neon gas is modelled as an idealised steady-state Townsend experiment and analysed theoretically using (a) multi-term solution of Boltzmann equation and (b) Monte-Carlo simulation. Theoretical electron periodic electron structures, together with the `window' of reduced fields in which they occur, are compared with experiment, and it is explained why it is necessary to account for all competing scattering processes in order to explain the observed experimental `wavelength'. The study highlights the fundamental flaws in trying to explain the observations in terms of a single, assumed dominant electronic excitation process, as is the case in text books and the myriad of misleading web sites.

White, R. D.; Robson, R. E.; Nicoletopoulos, P.; Dujko, S.

2012-05-01

475

Self-medication among traumatized youth: structural equation modeling of pathways between trauma history, substance misuse, and psychological distress.  

PubMed

In an effort to self-medicate psychological distress stemming from exposure to traumatic life events, at-risk youth may be likely to seek intoxication via substance use. Concomitantly, self-medication with psychoactive substances is theorized to confer risk of developing future psychiatric and substance use disorders. The present study employed structural equation modeling to examine self-medication among a sample of 723 youth in residential treatment for antisocial behavior via recursive and non-recursive relationships between trauma history, substance misuse, and psychological distress. Results supported study hypotheses that: (a) the effects of trauma history on psychological distress are partially mediated by substance misuse, and (b) exposure to traumatic life events drives a feedback loop between substance misuse and psychological distress. Findings from this large-scale survey of adolescents exhibiting behavioral dysfunction suggest that identification of self-medication processes among traumatized youth may be crucial for developing targeted prevention and treatment initiatives. PMID:22454227

Garland, Eric L; Pettus-Davis, Carrie; Howard, Matthew O

2013-04-01

476

Adult ADHD Symptoms and Five Factor Model Traits in a Clinical Sample: A Structural Equation Modeling Approach  

PubMed Central

Relationships among Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms and adult personality traits have not been examined in larger clinically diagnosed samples. We collected multi-source ADHD symptom and self-report NEO Five-Factor Inventory (Costa & McCrae, 1992a) data from 117 adults with ADHD and tested symptom-trait associations using structural equation modeling. The final model fit the data. Inattention was positively associated with Neuroticism and negatively associated with Conscientiousness. Based on ADHD expression in adulthood, hyperactivity and impulsivity were estimated as separate constructs and showed differential relationships to Extraversion and Agreeableness. A significant positive relationship between Hyperactivity and Conscientiousness arose in the context of other pathways. ADHD symptoms are reliably associated with personality traits, suggesting a complex in