Vibration-based structural health monitoring using adaptive statistical method under varying environmental condition

NASA Astrophysics Data System (ADS)

Jin, Seung-Seop; Jung, Hyung-Jo

2014-03-01

It is well known that the dynamic properties of a structure such as natural frequencies depend not only on damage but also on environmental condition (e.g., temperature). The variation in dynamic characteristics of a structure due to environmental condition may mask damage of the structure. Without taking the change of environmental condition into account, false-positive or false-negative damage diagnosis may occur so that structural health monitoring becomes unreliable. In order to address this problem, an approach to construct a regression model based on structural responses considering environmental factors has been usually used by many researchers. The key to success of this approach is the formulation between the input and output variables of the regression model to take into account the environmental variations. However, it is quite challenging to determine proper environmental variables and measurement locations in advance for fully representing the relationship between the structural responses and the environmental variations. One alternative (i.e., novelty detection) is to remove the variations caused by environmental factors from the structural responses by using multivariate statistical analysis (e.g., principal component analysis (PCA), factor analysis, etc.). The success of this method is deeply depending on the accuracy of the description of normal condition. Generally, there is no prior information on normal condition during data acquisition, so that the normal condition is determined by subjective perspective with human-intervention. The proposed method is a novel adaptive multivariate statistical analysis for monitoring of structural damage detection under environmental change. One advantage of this method is the ability of a generative learning to capture the intrinsic characteristics of the normal condition. The proposed method is tested on numerically simulated data for a range of noise in measurement under environmental variation. A comparative

Latent factor structure of a behavioral economic marijuana demand curve.

PubMed

Aston, Elizabeth R; Farris, Samantha G; MacKillop, James; Metrik, Jane

2017-08-01

Drug demand, or relative value, can be assessed via analysis of behavioral economic purchase task performance. Five demand indices are typically obtained from drug purchase tasks. The goal of this research was to determine whether metrics of marijuana reinforcement from a marijuana purchase task (MPT) exhibit a latent factor structure that efficiently characterizes marijuana demand. Participants were regular marijuana users (n = 99; 37.4% female, 71.5% marijuana use days [5 days/week], 15.2% cannabis dependent) who completed study assessments, including the MPT, during a baseline session. Principal component analysis was used to examine the latent structure underlying MPT indices. Concurrent validity was assessed via examination of relationships between latent factors and marijuana use, past quit attempts, and marijuana expectancies. A two-factor solution was confirmed as the best fitting structure, accounting for 88.5% of the overall variance. Factor 1 (65.8% variance) reflected "Persistence," indicating sensitivity to escalating marijuana price, which comprised four MPT indices (elasticity, O max , P max , and breakpoint). Factor 2 (22.7% variance) reflected "Amplitude," indicating the amount consumed at unrestricted price (intensity). Persistence factor scores were associated with fewer past marijuana quit attempts and lower expectancies of negative use outcomes. Amplitude factor scores were associated with more frequent use, dependence symptoms, craving severity, and positive marijuana outcome expectancies. Consistent with research on alcohol and cigarette purchase tasks, the MPT can be characterized with a latent two-factor structure. Thus, demand for marijuana appears to encompass distinct dimensions of price sensitivity and volumetric consumption, with differential relations to other aspects of marijuana motivation.

Measuring the structure factor of simple fluids under extreme conditions

NASA Astrophysics Data System (ADS)

Weck, Gunnar

2013-06-01

enabling quantitative structure factor measurement, even for the weakest x-ray scatterer liquid. Experimental results on fluid hydrogen will be presented to test the limits of this new setup. In collaboration with Gaston Garbarino, ESRF, France; Frederic Datchi, Sandra Ninet, Université Pierre et Marie Curie-Paris VI, France; Dylan Spaulding, Paul Loubeyre, CEA, DAM, DIF, France; and Mohamed Mezouar, ESRF, France.

Immune Organs and Haemopoietic System Under Modelling of the Mission Factors

NASA Astrophysics Data System (ADS)

Sapin, M. R.; Grigoriev, A. I.; Erofeeva, L. M.; Grigorenko, D. E.; Fedorenko, B. S.

1997-07-01

Literary and experimental data on the character of changes in immune organs and lymphoid tissue of respiratory system and digestive system in laboratory animals during the mission factors model are given. Inhibition of reproductive function in bone marrow, thymus and spleen under irradiation of gamma-rays and accelerated carbon ions, tensity of immune response in the lymphoid structures of larynx, trachea and bronchi under the influence of acetaldehyde vapors and decrease of lymphoid tissue square on histological series in spleen and small intestine with an increase of concentration of microbial bodies in the drinking water were estimated.

Factor Structure Consistency in the Bruininks-Oseretsky Test--Short Form.

ERIC Educational Resources Information Center

Broadhead, Geoffrey D.; Bruininks, Robert H.

1983-01-01

The underlying structure of the motor abilities represented by the "Short Form of the Bruininks-Oseretsky Test of Motor Proficiency," along with the consistency of the emerging factors by sex and two chronological age (CA) levels, were studied with 765 nondisabled children 4.6 to 14.6 years old. (Author/SEW)

An empirical examination of the factor structure of compassion.

PubMed

Gu, Jenny; Cavanagh, Kate; Baer, Ruth; Strauss, Clara

2017-01-01

Compassion has long been regarded as a core part of our humanity by contemplative traditions, and in recent years, it has received growing research interest. Following a recent review of existing conceptualisations, compassion has been defined as consisting of the following five elements: 1) recognising suffering, 2) understanding the universality of suffering in human experience, 3) feeling moved by the person suffering and emotionally connecting with their distress, 4) tolerating uncomfortable feelings aroused (e.g., fear, distress) so that we remain open to and accepting of the person suffering, and 5) acting or being motivated to act to alleviate suffering. As a prerequisite to developing a high quality compassion measure and furthering research in this field, the current study empirically investigated the factor structure of the five-element definition using a combination of existing and newly generated self-report items. This study consisted of three stages: a systematic consultation with experts to review items from existing self-report measures of compassion and generate additional items (Stage 1), exploratory factor analysis of items gathered from Stage 1 to identify the underlying structure of compassion (Stage 2), and confirmatory factor analysis to validate the identified factor structure (Stage 3). Findings showed preliminary empirical support for a five-factor structure of compassion consistent with the five-element definition. However, findings indicated that the 'tolerating' factor may be problematic and not a core aspect of compassion. This possibility requires further empirical testing. Limitations with items from included measures lead us to recommend against using these items collectively to assess compassion. Instead, we call for the development of a new self-report measure of compassion, using the five-element definition to guide item generation. We recommend including newly generated 'tolerating' items in the initial item pool, to determine

Investigating the Underlying Factors of Corruption in the Public Construction Sector: Evidence from China.

PubMed

Shan, Ming; Le, Yun; Yiu, Kenneth T W; Chan, Albert P C; Hu, Yi

2017-12-01

Over recent years, the issue of corruption in the public construction sector has attracted increasing attention from both practitioners and researchers worldwide. However, limited efforts are available for investigating the underlying factors of corruption in this sector. Thus, this study attempted to bridge this knowledge gap by exploring the underlying factors of corruption in the public construction sector of China. To achieve this goal, a total of 14 structured interviews were first carried out, and a questionnaire survey was then administered to 188 professionals in China. Two iterations of multivariate analysis approaches, namely, stepwise multiple regression analysis and partial least squares structural equation modeling were successively utilized to analyze the collected data. In addition, a case study was also conducted to triangulate the findings obtained from the statistical analysis. The results generated from these three research methods achieve the same conclusion: the most influential underlying factor leading to corruption was immorality, followed by opacity, unfairness, procedural violation, and contractual violation. This study has contributed to the body of knowledge by exploring the properties of corruption in the public construction sector. The findings from this study are also valuable to the construction authorities as they can assist in developing more effective anti-corruption strategies.

Negative Mood and Obsessive-Compulsive Related Clinical Constructs: An Examination of Underlying Factors

PubMed Central

Britton, Gary I.; Davey, Graham C. L.

2017-01-01

Emerging evidence suggests that many of the clinical constructs used to help understand and explain obsessive-compulsive (OC) symptoms, and negative mood, may be causally interrelated. One approach to understanding this interrelatedness is a motivational systems approach. This approach suggests that rather than considering clinical constructs and negative affect as separable entities, they are all features of an integrated threat management system, and as such are highly coordinated and interdependent. The aim of the present study was to examine if clinical constructs related to OC symptoms and negative mood are best treated as separable or, alternatively, if these clinical constructs and negative mood are best seen as indicators of an underlying superordinate variable, as would be predicted by a motivational systems approach. A sample of 370 student participants completed measures of mood and the clinical constructs of inflated responsibility, intolerance of uncertainty, not just right experiences, and checking stop rules. An exploratory factor analysis suggested two plausible factor structures, one where all construct items and negative mood items loaded onto one underlying superordinate variable, and a second structure comprising of five factors, where each item loaded onto a factor representative of what the item was originally intended to measure. A confirmatory factor analysis showed that the five factor model was preferential to the one factor model, suggesting the four constructs and negative mood are best conceptualized as separate variables. Given the predictions of a motivational systems approach were not supported in the current study, other possible explanations for the causal interrelatedness between clinical constructs and negative mood are discussed. PMID:28959224

Design Optimization of Composite Structures under Uncertainty

NASA Technical Reports Server (NTRS)

Haftka, Raphael T.

2003-01-01

Design optimization under uncertainty is computationally expensive and is also challenging in terms of alternative formulation. The work under the grant focused on developing methods for design against uncertainty that are applicable to composite structural design with emphasis on response surface techniques. Applications included design of stiffened composite plates for improved damage tolerance, the use of response surfaces for fitting weights obtained by structural optimization, and simultaneous design of structure and inspection periods for fail-safe structures.

Colloidal Aggregate Structure under Shear by USANS

NASA Astrophysics Data System (ADS)

Chatterjee, Tirtha; van Dyk, Antony K.; Ginzburg, Valeriy V.; Nakatani, Alan I.

2015-03-01

Paints are complex formulations of polymeric binders, inorganic pigments, dispersants, surfactants, colorants, rheology modifiers, and other additives. A commercially successful paint exhibits a desired viscosity profile over a wide shear rate range from 10-5 s-1 for settling to >104 s-1 for rolling, and spray applications. Understanding paint formulation structure is critical as it governs the paint viscosity profile. However, probing paint formulation structure under shear is a challenging task due to the formulation complexity containing structures with different hierarchical length scales and their alterations under the influence of an external flow field. In this work mesoscale structures of paint formulations under shear are investigated using Ultra Small-Angle Neutron Scattering (rheo-USANS). Contrast match conditions were utilized to independently probe the structure of latex binder particle aggregates and the TiO2 pigment particle aggregates. Rheo-USANS data revealed that the aggregates are fractal in nature and their self-similarity dimensions and correlations lengths depend on the chemistry of the binder particles, the type of rheology modifier present and the shear stress imposed upon the formulation. These results can be explained in the framework of diffusion and reaction limited transient aggregates structure evolution under simple shear.

Exploring the factor structure of the Food Cravings Questionnaire-Trait in Cuban adults

PubMed Central

Rodríguez-Martín, Boris C.; Molerio-Pérez, Osana

2014-01-01

Food cravings refer to an intense desire to eat specific foods. The Food Cravings Questionnaire-Trait (FCQ-T) is the most commonly used instrument to assess food cravings as a multidimensional construct. Its 39 items have an underlying nine-factor structure for both the original English and Spanish version; but subsequent studies yielded fewer factors. As a result, a 15-item version of the FCQ-T with one-factor structure has been proposed (FCQ-T-reduced; see this Research Topic). The current study aimed to explore the factor structure of the Spanish version for both the FCQ-T and FCQ-T-reduced in a sample of 1241 Cuban adults. Results showed a four-factor structure for the FCQ-T, which explained 55% of the variance. Factors were highly correlated. Using the items of the FCQ-T-reduced only showed a one-factor structure, which explained 52% of the variance. Both versions of the FCQ-T were positively correlated with body mass index (BMI), scores on the Food Thoughts Suppression Inventory and weight cycling. In addition, women had higher scores than men and restrained eaters had higher scores than unrestrained eaters. To summarize, results showed that (1) the FCQ-T factor structure was significantly reduced in Cuban adults and (2) the FCQ-T-reduced may represent a good alternative to efficiently assess food craving on a trait level. PMID:24672503

Comparing Factor Structures of Adolescent Psychopathology

ERIC Educational Resources Information Center

Verona, Edelyn; Javdani, Shabnam; Sprague, Jenessa

2011-01-01

Research on the structure of adolescent psychopathology can provide information on broad factors that underlie different forms of maladjustment in youths. Multiple studies from the literature on adult populations suggest that 2 factors, Internalizing and Externalizing, meaningfully comprise the factor structure of adult psychopathology (e.g.,…

Human Factors Research Under Ground-Based and Space Conditions. Part 1

NASA Technical Reports Server (NTRS)

1997-01-01

Session TP2 includes short reports concerning: (1) Human Factors Engineering of the International space Station Human Research Facility; (2) Structured Methods for Identifying and Correcting Potential Human Errors in Space operation; (3) An Improved Procedure for Selecting Astronauts for Extended Space Missions; (4) The NASA Performance Assessment Workstation: Cognitive Performance During Head-Down Bedrest; (5) Cognitive Performance Aboard the Life and Microgravity Spacelab; and (6) Psychophysiological Reactivity Under MIR-Simulation and Real Micro-G.

Numerical simulation of an elastic structure behavior under transient fluid flow excitation

NASA Astrophysics Data System (ADS)

Afanasyeva, Irina N.; Lantsova, Irina Yu.

2017-01-01

This paper deals with the verification of a numerical technique of modeling fluid-structure interaction (FSI) problems. The configuration consists of incompressible viscous fluid around an elastic structure in the channel. External flow is laminar. Multivariate calculations are performed using special software ANSYS CFX and ANSYS Mechanical. Different types of parameters of mesh deformation and solver controls (time step, under relaxation factor, number of iterations at coupling step) were tested. The results are presented in tables and plots in comparison with reference data.

The preparation and structure of salty ice VII under pressure

NASA Astrophysics Data System (ADS)

Klotz, Stefan; Bove, Livia E.; Strässle, Thierry; Hansen, Thomas C.; Saitta, Antonino M.

2009-05-01

It is widely accepted that ice, no matter what phase, is unable to incorporate large amounts of salt into its structure. This conclusion is based on the observation that on freezing of salt water, ice expels the salt almost entirely as brine. Here, we show that this behaviour is not an intrinsic physico-chemical property of ice phases. We demonstrate by neutron diffraction that substantial amounts of dissolved LiCl can be built homogeneously into the ice VII structure if it is produced by recrystallization of its glassy (amorphous) state under pressure. Such `alloyed' ice VII has significantly different structural properties compared with pure ice VII, such as an 8% larger unit cell volume, 5 times larger displacement factors, an absence of a transition to an ordered ice VIII structure and plasticity. Our study suggests that there could be a whole new class of `salty' high-pressure ice forms.

The preparation and structure of salty ice VII under pressure.

PubMed

Klotz, Stefan; Bove, Livia E; Strässle, Thierry; Hansen, Thomas C; Saitta, Antonino M

2009-05-01

It is widely accepted that ice, no matter what phase, is unable to incorporate large amounts of salt into its structure. This conclusion is based on the observation that on freezing of salt water, ice expels the salt almost entirely as brine. Here, we show that this behaviour is not an intrinsic physico-chemical property of ice phases. We demonstrate by neutron diffraction that substantial amounts of dissolved LiCl can be built homogeneously into the ice VII structure if it is produced by recrystallization of its glassy (amorphous) state under pressure. Such 'alloyed' ice VII has significantly different structural properties compared with pure ice VII, such as an 8% larger unit cell volume, 5 times larger displacement factors, an absence of a transition to an ordered ice VIII structure and plasticity. Our study suggests that there could be a whole new class of 'salty' high-pressure ice forms.

The Factor Structure and Sources of Variation Underlying the Social Learning Environment Rating Scales: Monograph 1.

ERIC Educational Resources Information Center

Warshow, Joyce P.; Bepko, Raymond A.

Seventeen intermediate level classes for the educable mentally retarded were involved in an investigation of the factor structure of the Social Learning Environment Rating Scale (SLERS), an instrument designed to quantify teacher-student behavior based on the Social Learning Curriculum (SLC). The 17 classes were observed implementing six…

Influence of DNA sequence on the structure of minicircles under torsional stress

PubMed Central

Wang, Qian; Irobalieva, Rossitza N.; Chiu, Wah; Schmid, Michael F.; Fogg, Jonathan M.; Zechiedrich, Lynn

2017-01-01

Abstract The sequence dependence of the conformational distribution of DNA under various levels of torsional stress is an important unsolved problem. Combining theory and coarse-grained simulations shows that the DNA sequence and a structural correlation due to topology constraints of a circle are the main factors that dictate the 3D structure of a 336 bp DNA minicircle under torsional stress. We found that DNA minicircle topoisomers can have multiple bend locations under high torsional stress and that the positions of these sharp bends are determined by the sequence, and by a positive mechanical correlation along the sequence. We showed that simulations and theory are able to provide sequence-specific information about individual DNA minicircles observed by cryo-electron tomography (cryo-ET). We provided a sequence-specific cryo-ET tomogram fitting of DNA minicircles, registering the sequence within the geometric features. Our results indicate that the conformational distribution of minicircles under torsional stress can be designed, which has important implications for using minicircle DNA for gene therapy. PMID:28609782

Dynamic Structure Factor: An Introduction

NASA Astrophysics Data System (ADS)

Sturm, K.

1993-02-01

The doubly differential cross-section for weak inelastic scattering of waves or particles by manybody systems is derived in Born approximation and expressed in terms of the dynamic structure factor according to van Hove. The application of this very general scheme to scattering of neutrons, x-rays and high-energy electrons is discussed briefly. The dynamic structure factor, which is the space and time Fourier transform of the density-density correlation function, is a property of the many-body system independent of the external probe and carries information on the excitation spectrum of the system. The relation of the electronic structure factor to the density-density response function defined in linear-response theory is shown using the fluctuation-dissipation theorem. This is important for calculations, since the response function can be calculated approximately from the independent-particle response function in self-consistent field approximations, such as the random-phase approximation or the local-density approximation of the density functional theory. Since the density-density response function also determines the dielectric function, the dynamic structure can be expressed by the dielectric function.

Internal structure of the Community Assessment of Psychic Experiences-Positive (CAPE-P15) scale: Evidence for a general factor.

PubMed

Núñez, D; Arias, V; Vogel, E; Gómez, L

2015-07-01

Psychotic-like experiences (PLEs) are prevalent in the general population and are associated with poor mental health and a higher risk of psychiatric disorders. The Community Assessment of Psychic Experiences-Positive (CAPE-P15) scale is a self-screening questionnaire to address subclinical positive psychotic symptoms (PPEs) in community contexts. Although its psychometric properties seem to be adequate to screen PLEs, further research is needed to evaluate certain validity aspects, particularly its internal structure and its functioning in different populations. To uncover the optimal factor structure of the CAPE-P15 scale in adolescents aged 13 to 18 years using factorial analysis methods suitable to manage categorical variables. A sample of 727 students from six secondary public schools and 245 university students completed the CAPE-P15. The dimensionality of the CAPE-P15 was tested through exploratory structural equation models (ESEMs). Based on the ESEM results, we conducted a confirmatory factor analysis (CFA) to contrast two factorial structures that potentially underlie the symptoms described by the scale: a) three correlated factors and b) a hierarchical model composed of a general PLE factor plus three specific factors (persecutory ideation, bizarre experiences, and perceptual abnormalities). The underlying structure of PLEs assessed by the CAPE-P15 is consistent with both multidimensional and hierarchical solutions. However, the latter show the best fit. Our findings reveal the existence of a strong general factor underlying scale scores. Compared with the specific factors, the general factor explains most of the common variance observed in subjects' responses. The findings suggest that the factor structure of subthreshold psychotic experiences addressed by the CAPE-P15 can be adequately represented by a general factor and three separable specific traits, supporting the hypothesis according to which there might be a common source underlying PLEs

Internal Control, Powerful Others, and Chance: A Confirmation of Levenson's Factor Structure.

ERIC Educational Resources Information Center

Walkey, Frank H.

1979-01-01

The internal-external locus of control scales of Rotter and Levenson and the Marlowe-Crowne Social Desirability Scale were completed by 156 undergraduates. The three-factor structure underlying Levenson's questionnaire was clearly confirmed. Some new evidence for the multidimensionality of Rotter's scale was also presented. (Author/GDC)

Evaluating WAIS-IV structure through a different psychometric lens: structural causal model discovery as an alternative to confirmatory factor analysis.

PubMed

van Dijk, Marjolein J A M; Claassen, Tom; Suwartono, Christiany; van der Veld, William M; van der Heijden, Paul T; Hendriks, Marc P H

Since the publication of the WAIS-IV in the U.S. in 2008, efforts have been made to explore the structural validity by applying factor analysis to various samples. This study aims to achieve a more fine-grained understanding of the structure of the Dutch language version of the WAIS-IV (WAIS-IV-NL) by applying an alternative analysis based on causal modeling in addition to confirmatory factor analysis (CFA). The Bayesian Constraint-based Causal Discovery (BCCD) algorithm learns underlying network structures directly from data and assesses more complex structures than is possible with factor analysis. WAIS-IV-NL profiles of two clinical samples of 202 patients (i.e. patients with temporal lobe epilepsy and a mixed psychiatric outpatient group) were analyzed and contrasted with a matched control group (N = 202) selected from the Dutch standardization sample of the WAIS-IV-NL to investigate internal structure by means of CFA and BCCD. With CFA, the four-factor structure as proposed by Wechsler demonstrates acceptable fit in all three subsamples. However, BCCD revealed three consistent clusters (verbal comprehension, visual processing, and processing speed) in all three subsamples. The combination of Arithmetic and Digit Span as a coherent working memory factor could not be verified, and Matrix Reasoning appeared to be isolated. With BCCD, some discrepancies from the proposed four-factor structure are exemplified. Furthermore, these results fit CHC theory of intelligence more clearly. Consistent clustering patterns indicate these results are robust. The structural causal discovery approach may be helpful in better interpreting existing tests, the development of new tests, and aid in diagnostic instruments.

Finding imaging patterns of structural covariance via Non-Negative Matrix Factorization.

PubMed

Sotiras, Aristeidis; Resnick, Susan M; Davatzikos, Christos

2015-03-01

In this paper, we investigate the use of Non-Negative Matrix Factorization (NNMF) for the analysis of structural neuroimaging data. The goal is to identify the brain regions that co-vary across individuals in a consistent way, hence potentially being part of underlying brain networks or otherwise influenced by underlying common mechanisms such as genetics and pathologies. NNMF offers a directly data-driven way of extracting relatively localized co-varying structural regions, thereby transcending limitations of Principal Component Analysis (PCA), Independent Component Analysis (ICA) and other related methods that tend to produce dispersed components of positive and negative loadings. In particular, leveraging upon the well known ability of NNMF to produce parts-based representations of image data, we derive decompositions that partition the brain into regions that vary in consistent ways across individuals. Importantly, these decompositions achieve dimensionality reduction via highly interpretable ways and generalize well to new data as shown via split-sample experiments. We empirically validate NNMF in two data sets: i) a Diffusion Tensor (DT) mouse brain development study, and ii) a structural Magnetic Resonance (sMR) study of human brain aging. We demonstrate the ability of NNMF to produce sparse parts-based representations of the data at various resolutions. These representations seem to follow what we know about the underlying functional organization of the brain and also capture some pathological processes. Moreover, we show that these low dimensional representations favorably compare to descriptions obtained with more commonly used matrix factorization methods like PCA and ICA. Copyright © 2014 Elsevier Inc. All rights reserved.

Finding Imaging Patterns of Structural Covariance via Non-Negative Matrix Factorization

PubMed Central

Sotiras, Aristeidis; Resnick, Susan M.; Davatzikos, Christos

2015-01-01

In this paper, we investigate the use of Non-Negative Matrix Factorization (NNMF) for the analysis of structural neuroimaging data. The goal is to identify the brain regions that co-vary across individuals in a consistent way, hence potentially being part of underlying brain networks or otherwise influenced by underlying common mechanisms such as genetics and pathologies. NNMF offers a directly data-driven way of extracting relatively localized co-varying structural regions, thereby transcending limitations of Principal Component Analysis (PCA), Independent Component Analysis (ICA) and other related methods that tend to produce dispersed components of positive and negative loadings. In particular, leveraging upon the well known ability of NNMF to produce parts-based representations of image data, we derive decompositions that partition the brain into regions that vary in consistent ways across individuals. Importantly, these decompositions achieve dimensionality reduction via highly interpretable ways and generalize well to new data as shown via split-sample experiments. We empirically validate NNMF in two data sets: i) a Diffusion Tensor (DT) mouse brain development study, and ii) a structural Magnetic Resonance (sMR) study of human brain aging. We demonstrate the ability of NNMF to produce sparse parts-based representations of the data at various resolutions. These representations seem to follow what we know about the underlying functional organization of the brain and also capture some pathological processes. Moreover, we show that these low dimensional representations favorably compare to descriptions obtained with more commonly used matrix factorization methods like PCA and ICA. PMID:25497684

Recovering hidden diagonal structures via non-negative matrix factorization with multiple constraints.

PubMed

Yang, Xi; Han, Guoqiang; Cai, Hongmin; Song, Yan

2017-03-31

Revealing data with intrinsically diagonal block structures is particularly useful for analyzing groups of highly correlated variables. Earlier researches based on non-negative matrix factorization (NMF) have been shown to be effective in representing such data by decomposing the observed data into two factors, where one factor is considered to be the feature and the other the expansion loading from a linear algebra perspective. If the data are sampled from multiple independent subspaces, the loading factor would possess a diagonal structure under an ideal matrix decomposition. However, the standard NMF method and its variants have not been reported to exploit this type of data via direct estimation. To address this issue, a non-negative matrix factorization with multiple constraints model is proposed in this paper. The constraints include an sparsity norm on the feature matrix and a total variational norm on each column of the loading matrix. The proposed model is shown to be capable of efficiently recovering diagonal block structures hidden in observed samples. An efficient numerical algorithm using the alternating direction method of multipliers model is proposed for optimizing the new model. Compared with several benchmark models, the proposed method performs robustly and effectively for simulated and real biological data.

Adaptive vibration control of structures under earthquakes

NASA Astrophysics Data System (ADS)

Lew, Jiann-Shiun; Juang, Jer-Nan; Loh, Chin-Hsiung

2017-04-01

techniques, for structural vibration suppression under earthquakes. Various control strategies have been developed to protect structures from natural hazards and improve the comfort of occupants in buildings. However, there has been little development of adaptive building control with the integration of real-time system identification and control design. Generalized predictive control, which combines the process of real-time system identification and the process of predictive control design, has received widespread acceptance and has been successfully applied to various test-beds. This paper presents a formulation of the predictive control scheme for adaptive vibration control of structures under earthquakes. Comprehensive simulations are performed to demonstrate and validate the proposed adaptive control technique for earthquake-induced vibration of a building.

Factor structure and criterion validity across the full scale and ten short forms of the CES-D among Chinese adolescents.

PubMed

Yang, Wenhui; Xiong, Ge; Garrido, Luis Eduardo; Zhang, John X; Wang, Meng-Cheng; Wang, Chong

2018-04-16

We systematically examined the factor structure and criterion validity across the full scale and 10 short forms of the Center for Epidemiological Studies Depression Scale (CES-D) with Chinese youth. Participants were 5,434 Chinese adolescents in Grades 7 to 12 who completed the full CES-D; 612 of them further completed a structured diagnostic interview with the major depressive disorder (MDD) module of the Kiddie Schedule for Affective Disorder and Schizophrenia for School-age Children. Using a split-sample approach, a series of 4-, 3-, 2-, and 1-factor models were tested using exploratory structural equation modeling and cross-validated using confirmatory factor analysis; the dimensionality was also evaluated by parallel analysis in conjunction with the scree test and aided by factor mixture analysis. The results indicated that a single-factor model of depression with a wording method factor fitted the data well, and was the optimal structure underlying the scores of the full and shortened CES-D. Additionally, receiver operating characteristic curve analyses for MDD case detection showed that the CES-D full-scale scores accurately detected MDD youth (area under the curve [AUC] = .84). Furthermore, the short-form scores produced comparable AUCs with the full scale (.82 to .85), as well as similar levels of sensitivity and specificity when using optimal cutoffs. These findings suggest that depression among Chinese adolescents can be adequately measured and screened for by a single-factor structure underlying the CES-D scores, and that the short forms provide a viable alternative to the full instrument. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Gender differences in the factor structure of posttraumatic stress disorder symptoms in war-exposed adolescents.

PubMed

Armour, Cherie; Elhai, Jon D; Layne, Christopher M; Shevlin, Mark; Duraković-Belko, Elvira; Djapo, Nermin; Pynoos, Robert S

2011-05-01

DSM-IV's three-factor model of posttraumatic stress disorder (PTSD) is rarely empirically supported, whereas other four-factor models (King et al., 1998; Simms, Watson, & Doebbeling, 2002) have proven to be better representations of PTSD's latent structure. To date, a clear consensus as to which model provides the best representation of PTSD's underlying dimensions has yet to be reached. The current study investigated whether gender is associated with factor structure differences using the King et al. (1998) model of reexperiencing, avoidance, numbing, and hyperarousal PTSD symptoms. Participants were war-exposed Bosnian secondary/high school boys and girls (N=1572) assessed nearly two years after the 1992-1995 Bosnian conflict. Confirmatory factor analytic tests of measurement invariance across PTSD model parameters revealed many significant sex-linked differences. Implications regarding the potential role of gender as a moderator of the King et al. (1998) model's factor structure are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Factor structure and gender stability in the multidimensional condom attitudes scale.

PubMed

Starosta, Amy J; Berghoff, Christopher R; Earleywine, Mitch

2015-06-01

Sexually transmitted infections continue to trouble the United States and can be attenuated through increased condom use. Attitudes about condoms are an important multidimensional factor that can affect sexual health choices and have been successfully measured using the Multidimensional Condom Attitudes Scale (MCAS). Such attitudes have the potential to vary between men and women, yet little work has been undertaken to identify if the MCAS accurately captures attitudes without being influenced by underlying gender biases. We examined the factor structure and gender invariance on the MCAS using confirmatory factor analysis and item response theory, within-subscale differential item functioning analyses. More than 770 participants provided data via the Internet. Results of differential item functioning analyses identified three items as differentially functioning between the genders, and removal of these items is recommended. Findings confirmed the previously hypothesized multidimensional nature of condom attitudes and the five-factor structure of the MCAS even after the removal of the three problematic items. In general, comparisons across genders using the MCAS seem reasonable from a methodological standpoint. Results are discussed in terms of improving sexual health research and interventions. © The Author(s) 2014.

The importance of building construction materials relative to other factors affecting structure survival during wildfire

USGS Publications Warehouse

Syphard, Alexandra D.; Brennan, Teresa J.; Keeley, Jon E.

2017-01-01

Structure loss to wildfire is a serious problem in wildland-urban interface areas across the world. Laboratory experiments suggest that fire-resistant building construction and design could be important for reducing structure destruction, but these need to be evaluated under real wildfire conditions, especially relative to other factors. Using empirical data from destroyed and surviving structures from large wildfires in southern California, we evaluated the relative importance of building construction and structure age compared to other local and landscape-scale variables associated with structure survival. The local-scale analysis showed that window preparation was especially important but, in general, creating defensible space adjacent to the home was as important as building construction. At the landscape scale, structure density and structure age were the two most important factors affecting structure survival, but there was a significant interaction between them. That is, young structure age was most important in higher-density areas where structure survival overall was more likely. On the other hand, newer-construction structures were less likely to survive wildfires at lower density. Here, appropriate defensible space near the structure and accessibility to major roads were important factors. In conclusion, community safety is a multivariate problem that will require a comprehensive solution involving land use planning, fire-safe construction, and property maintenance.

Synchronization invariance under network structural transformations

NASA Astrophysics Data System (ADS)

Arola-Fernández, Lluís; Díaz-Guilera, Albert; Arenas, Alex

2018-06-01

Synchronization processes are ubiquitous despite the many connectivity patterns that complex systems can show. Usually, the emergence of synchrony is a macroscopic observable; however, the microscopic details of the system, as, e.g., the underlying network of interactions, is many times partially or totally unknown. We already know that different interaction structures can give rise to a common functionality, understood as a common macroscopic observable. Building upon this fact, here we propose network transformations that keep the collective behavior of a large system of Kuramoto oscillators invariant. We derive a method based on information theory principles, that allows us to adjust the weights of the structural interactions to map random homogeneous in-degree networks into random heterogeneous networks and vice versa, keeping synchronization values invariant. The results of the proposed transformations reveal an interesting principle; heterogeneous networks can be mapped to homogeneous ones with local information, but the reverse process needs to exploit higher-order information. The formalism provides analytical insight to tackle real complex scenarios when dealing with uncertainty in the measurements of the underlying connectivity structure.

Pragmatics fragmented: the factor structure of the Dutch children's communication checklist (CCC).

PubMed

Geurts, Hilde M; Hartman, Catharina; Verté, Sylvie; Oosterlaan, Jaap; Roeyers, Herbert; Sergeant, Joseph A

2009-01-01

A number of disorders are associated with pragmatic difficulties. Instruments that can make subdivisions within the larger construct of pragmatics could be important tools for disentangling profiles of pragmatic difficulty in different disorders. The deficits underlying the observed pragmatic difficulties may be different for different disorders. To study the construct validity of a pragmatic language questionnaire. The construct of pragmatics is studied by applying exploratory factor analysis (EFA) and confirmatory factor analysis to the parent version of the Dutch Children's Communication Checklist (CCC; Bishop 1998 ). Parent ratings of 1589 typically developing children and 481 children with a clinical diagnosis were collected. Four different factor models derived from the original CCC scales and five different factor models based on EFA were compared with each other. The models were cross-validated. The EFA-derived models were substantively different from the originally proposed CCC factor structure. EFA models gave a slightly better fit than the models based on the original CCC scales, though neither provided a good fit to the parent data. Coherence seemed to be part of language form and not of pragmatics, which is in line with the adaptation of the CCC, the CCC-2 (Bishop 2003 ). Most pragmatic items clustered together in one factor and these pragmatic items also clustered with items related to social relationships and specific interests. The nine scales of the original CCC do not reflect the underlying factor structure. Therefore, scale composition may be improved on and scores on subscale level need to be interpreted cautiously. Therefore, in interpreting the CCC profiles, the overall measure might be more informative than the postulated subscales as more information is needed to determine which constructs the suggested subscales are actually measuring.

A Multidimensional Approach to Understanding Under-Eating in Homebound Older Adults: The Importance of Social Factors

ERIC Educational Resources Information Center

Locher, Julie L.; Ritchie, Christine S.; Robinson, Caroline O.; Roth, David L.; West, Delia Smith; Burgio, Kathryn L.

2008-01-01

Purpose: The purpose of this study was to identify relationships between medical, functional, economic, oral health, social, religious, and psychological factors and under-eating in homebound older adults. The focus of the study was on identifying potentially modifiable factors amenable to social and behavioral interventions. Design and Methods: A…

Bacterial Sigma Factors and Anti-Sigma Factors: Structure, Function and Distribution

PubMed Central

Paget, Mark S.

2015-01-01

Sigma factors are multi-domain subunits of bacterial RNA polymerase (RNAP) that play critical roles in transcription initiation, including the recognition and opening of promoters as well as the initial steps in RNA synthesis. This review focuses on the structure and function of the major sigma-70 class that includes the housekeeping sigma factor (Group 1) that directs the bulk of transcription during active growth, and structurally-related alternative sigma factors (Groups 2–4) that control a wide variety of adaptive responses such as morphological development and the management of stress. A recurring theme in sigma factor control is their sequestration by anti-sigma factors that occlude their RNAP-binding determinants. Sigma factors are then released through a wide variety of mechanisms, often involving branched signal transduction pathways that allow the integration of distinct signals. Three major strategies for sigma release are discussed: regulated proteolysis, partner-switching, and direct sensing by the anti-sigma factor. PMID:26131973

Fibroblast Growth Factors and Vascular Endothelial Growth Factor Promote Cardiac Reprogramming under Defined Conditions

PubMed Central

Yamakawa, Hiroyuki; Muraoka, Naoto; Miyamoto, Kazutaka; Sadahiro, Taketaro; Isomi, Mari; Haginiwa, Sho; Kojima, Hidenori; Umei, Tomohiko; Akiyama, Mizuha; Kuishi, Yuki; Kurokawa, Junko; Furukawa, Tetsushi; Fukuda, Keiichi; Ieda, Masaki

2015-01-01

Summary Fibroblasts can be directly reprogrammed into cardiomyocyte-like cells (iCMs) by overexpression of cardiac transcription factors, including Gata4, Mef2c, and Tbx5; however, this process is inefficient under serum-based culture conditions, in which conversion of partially reprogrammed cells into fully reprogrammed functional iCMs has been a major hurdle. Here, we report that a combination of fibroblast growth factor (FGF) 2, FGF10, and vascular endothelial growth factor (VEGF), termed FFV, promoted cardiac reprogramming under defined serum-free conditions, increasing spontaneously beating iCMs by 100-fold compared with those under conventional serum-based conditions. Mechanistically, FFV activated multiple cardiac transcriptional regulators and converted partially reprogrammed cells into functional iCMs through the p38 mitogen-activated protein kinase and phosphoinositol 3-kinase/AKT pathways. Moreover, FFV enabled cardiac reprogramming with only Mef2c and Tbx5 through the induction of cardiac reprogramming factors, including Gata4. Thus, defined culture conditions promoted the quality of cardiac reprogramming, and this finding provides new insight into the mechanism of cardiac reprogramming. PMID:26626177

Getting under the hood: how and for whom does increasing course structure work?

PubMed

Eddy, Sarah L; Hogan, Kelly A

2014-01-01

At the college level, the effectiveness of active-learning interventions is typically measured at the broadest scales: the achievement or retention of all students in a course. Coarse-grained measures like these cannot inform instructors about an intervention's relative effectiveness for the different student populations in their classrooms or about the proximate factors responsible for the observed changes in student achievement. In this study, we disaggregate student data by racial/ethnic groups and first-generation status to identify whether a particular intervention-increased course structure-works better for particular populations of students. We also explore possible factors that may mediate the observed changes in student achievement. We found that a "moderate-structure" intervention increased course performance for all student populations, but worked disproportionately well for black students-halving the black-white achievement gap-and first-generation students-closing the achievement gap with continuing-generation students. We also found that students consistently reported completing the assigned readings more frequently, spending more time studying for class, and feeling an increased sense of community in the moderate-structure course. These changes imply that increased course structure improves student achievement at least partially through increasing student use of distributed learning and creating a more interdependent classroom community. © 2014 S. L. Eddy and K. A. Hogan. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Thermal and Compositional Variation of Glassy Metal Structure Factors.

NASA Astrophysics Data System (ADS)

From, Milton

The x-ray total structure factor of the glassy -metal alloys Mg_{70}Zn_ {30}, Ca_{70}Mg_{30 } and Mg_{85.5}Cu _{14.5} has been measured at three temperatures: 9K, 150K, and 300K. The data have a statistical precision of about.8% and an absolute accuracy of roughly 3%. Percus-Yevick hard sphere structure factors may be fitted quite accurately to the data in the region of the first peak. In addition, the variation of the experimental structure factor with composition is found to be consistent with the Percus-Yevick theory. At low k values, Percus -Yevick and other theoretical model structure factors are in poor agreement with the data. Within experimental error, the temperature dependence of the structure factors is in agreement with the Debye plane wave phonon model of atomic vibrations. The measured structure factors are used to calculate the electrical resistivity from the Faber-Ziman equation. In most cases, the calculations yield both the correct magnitude of resistivity and sign of the temperature coefficient of resistivity.

Role of carbohydrate in multimeric structure of factor VIII/von Willebrand factor protein.

PubMed Central

Gralnick, H R; Williams, S B; Rick, M E

1983-01-01

The carbohydrate moiety of the factor VIII/von Willebrand (vW) factor protein is important in the expression of vW factor activity and the intravascular survival of the protein. Studies of normal human factor VIII/vW factor protein indicate that there is a requirement of a full complement of penultimate galactose for the maintenance of a normal multimeric structure. Release of penultimate galactose by beta-galactosidase or modification by galactose oxidase results in loss of the largest molecular weight multimers and increased numbers of intermediate and smaller multimers. In contrast, terminal galactose on the factor VIII/vW factor protein does not appear to play a significant role in the maintenance of the multimer organization. The abnormalities in multimeric structure and molecular size were demonstrated by NaDodSO4/polyacrylamide/agarose gel electrophoresis, NaDodSO4/glyoxyl-agarose electrophoresis, and sucrose density ultracentrifugation. These studies indicate that the penultimate galactose plays a role in the maintenance of the largest multimers of the factor VIII/vW factor protein. This may explain why, in some patients with variant forms of vW disease, a carbohydrate abnormality also may affect the multimeric structure of the plasma factor VIII/vW factor protein. Images PMID:6601805

Magnetic field effects on charge structure factors of gapped graphene structure

NASA Astrophysics Data System (ADS)

Rezania, Hamed; Tawoose, Nasrin

2018-02-01

We present the behaviors of dynamical and static charge susceptibilities of undoped gapped graphene using the Green's function approach in the context of tight binding model Hamiltonian. Specially, the effects of magnetic field on the plasmon modes of gapped graphene structure are investigated via calculating correlation function of charge density operators. Our results show the increase of magnetic field leads to disappear high frequency plasmon mode for gapped case. We also show that low frequency plasmon mode has not affected by increase of magnetic field and chemical potential. Finally the temperature dependence of static charge structure factor of gapp graphene structure is studied. The effects of both magnetic field and gap parameter on the static structure factor are discusses in details.

Structural fabrication quality as a factor of industrial facilities safety

NASA Astrophysics Data System (ADS)

Tishkov, E. V.; Kardaev, E. M.; Stolbova, S. Yu; Shishova, O. S.

2018-04-01

In the conditions of industrial facilities high wear degree, it is very important to ensure the possibility of their safe operation in order to avoid various kinds of accidents and catastrophes. As practice shows, industrial plant collapses can occur suddenly under normal operating conditions. Usually, such accidents can take place at different stages of structures life cycle. One of the reasons for this is the initially low quality of reinforced concrete structures fabrication. The article considers the factors contributing to the collapse of reinforced concrete structures of water purification tanks located on the territory of the Omsk Region. The main surveys results on tank structures after collapse with the use of ultrasonic and physical methods of investigation are presented. On the basis of the obtained data analysis, it was found that the main cause of the accidents was the insufficient load-bearing capacity of typical reinforced concrete structures, caused by defects in their fabrication in the factory conditions because of exceeding the standard displacement from the design position of the working reinforcement. Recommendations are given on the identification of defective structures and the prevention of similar accidents when operating similar tanks at manufacturing plants constructed from standard designs.

Facial first impressions and partner preference models: Comparable or distinct underlying structures?

PubMed

South Palomares, Jennifer K; Sutherland, Clare A M; Young, Andrew W

2017-12-17

Given the frequency of relationships nowadays initiated online, where impressions from face photographs may influence relationship initiation, it is important to understand how facial first impressions might be used in such contexts. We therefore examined the applicability of a leading model of verbally expressed partner preferences to impressions derived from real face images and investigated how the factor structure of first impressions based on potential partner preference-related traits might relate to a more general model of facial first impressions. Participants rated 1,000 everyday face photographs on 12 traits selected to represent (Fletcher, et al. 1999, Journal of Personality and Social Psychology, 76, 72) verbal model of partner preferences. Facial trait judgements showed an underlying structure that largely paralleled the tripartite structure of Fletcher et al.'s verbal preference model, regardless of either face gender or participant gender. Furthermore, there was close correspondence between the verbal partner preference model and a more general tripartite model of facial first impressions derived from a different literature (Sutherland et al., 2013, Cognition, 127, 105), suggesting an underlying correspondence between verbal conceptual models of romantic preferences and more general models of facial first impressions. © 2017 The British Psychological Society.

Fibroblast Growth Factors and Vascular Endothelial Growth Factor Promote Cardiac Reprogramming under Defined Conditions.

PubMed

Yamakawa, Hiroyuki; Muraoka, Naoto; Miyamoto, Kazutaka; Sadahiro, Taketaro; Isomi, Mari; Haginiwa, Sho; Kojima, Hidenori; Umei, Tomohiko; Akiyama, Mizuha; Kuishi, Yuki; Kurokawa, Junko; Furukawa, Tetsushi; Fukuda, Keiichi; Ieda, Masaki

2015-12-08

Fibroblasts can be directly reprogrammed into cardiomyocyte-like cells (iCMs) by overexpression of cardiac transcription factors, including Gata4, Mef2c, and Tbx5; however, this process is inefficient under serum-based culture conditions, in which conversion of partially reprogrammed cells into fully reprogrammed functional iCMs has been a major hurdle. Here, we report that a combination of fibroblast growth factor (FGF) 2, FGF10, and vascular endothelial growth factor (VEGF), termed FFV, promoted cardiac reprogramming under defined serum-free conditions, increasing spontaneously beating iCMs by 100-fold compared with those under conventional serum-based conditions. Mechanistically, FFV activated multiple cardiac transcriptional regulators and converted partially reprogrammed cells into functional iCMs through the p38 mitogen-activated protein kinase and phosphoinositol 3-kinase/AKT pathways. Moreover, FFV enabled cardiac reprogramming with only Mef2c and Tbx5 through the induction of cardiac reprogramming factors, including Gata4. Thus, defined culture conditions promoted the quality of cardiac reprogramming, and this finding provides new insight into the mechanism of cardiac reprogramming. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

High-pressure crystal structure of elastically isotropic CaTiO3 perovskite under hydrostatic and non-hydrostatic conditions.

PubMed

Zhao, Jing; Ross, Nancy L; Wang, Di; Angel, Ross J

2011-11-16

The structural evolution of orthorhombic CaTiO3 perovskite has been studied using high-pressure single-crystal x-ray diffraction under hydrostatic conditions up to 8.1 GPa and under a non-hydrostatic stress field formed in a diamond anvil cell (DAC) up to 4.7 GPa. Under hydrostatic conditions, the TiO6 octahedra become more tilted and distorted with increasing pressure, similar to other 2:4 perovskites. Under non-hydrostatic conditions, the experiments do not show any apparent difference in the internal structural variation from hydrostatic conditions and no additional tilts and distortions in the TiO6 octahedra are observed, even though the lattice itself becomes distorted due to the non-hydrostatic stress. The similarity between the hydrostatic and non-hydrostatic cases can be ascribed to the fact that CaTiO3 perovskite is nearly elastically isotropic and, as a consequence, its deviatoric unit-cell volume strain produced by the non-hydrostatic stress is very small; in other words, the additional octahedral tilts relevant to the extra unit-cell volume associated with the deviatoric unit-cell volume strain may be totally neglected. This study further addresses the role that three factors--the elastic properties, the crystal orientation and the pressure medium--have on the structural evolution of an orthorhombic perovskite loaded in a DAC under non-hydrostatic conditions. The influence of these factors can be clearly visualized by plotting the three-dimensional distribution of the deviatoric unit-cell volume strain in relation to the cylindrical axis of the DAC and indicates that, if the elasticity of a perovskite is nearly isotropic as it is for CaTiO3, the other two factors become relatively insignificant.

Exotic behavior and crystal structures of calcium under pressure

PubMed Central

Oganov, Artem R.; Ma, Yanming; Xu, Ying; Errea, Ion; Bergara, Aitor; Lyakhov, Andriy O.

2010-01-01

Experimental studies established that calcium undergoes several counterintuitive transitions under pressure: fcc → bcc → simple cubic → Ca-IV → Ca-V, and becomes a good superconductor in the simple cubic and higher-pressure phases. Here, using ab initio evolutionary simulations, we explore the behavior of Ca under pressure and find a number of new phases. Our structural sequence differs from the traditional picture for Ca, but is similar to that for Sr. The β-tin (I41/amd) structure, rather than simple cubic, is predicted to be the theoretical ground state at 0 K and 33–71 GPa. This structure can be represented as a large distortion of the simple cubic structure, just as the higher-pressure phases stable between 71 and 134 GPa. The structure of Ca-V, stable above 134 GPa, is a complex host-guest structure. According to our calculations, the predicted phases are superconductors with Tc increasing under pressure and reaching approximately 20 K at 120 GPa, in good agreement with experiment. PMID:20382865

Biology of Bone Tissue: Structure, Function, and Factors That Influence Bone Cells

PubMed Central

Florencio-Silva, Rinaldo; Sasso-Cerri, Estela; Simões, Manuel Jesus; Cerri, Paulo Sérgio

2015-01-01

Bone tissue is continuously remodeled through the concerted actions of bone cells, which include bone resorption by osteoclasts and bone formation by osteoblasts, whereas osteocytes act as mechanosensors and orchestrators of the bone remodeling process. This process is under the control of local (e.g., growth factors and cytokines) and systemic (e.g., calcitonin and estrogens) factors that all together contribute for bone homeostasis. An imbalance between bone resorption and formation can result in bone diseases including osteoporosis. Recently, it has been recognized that, during bone remodeling, there are an intricate communication among bone cells. For instance, the coupling from bone resorption to bone formation is achieved by interaction between osteoclasts and osteoblasts. Moreover, osteocytes produce factors that influence osteoblast and osteoclast activities, whereas osteocyte apoptosis is followed by osteoclastic bone resorption. The increasing knowledge about the structure and functions of bone cells contributed to a better understanding of bone biology. It has been suggested that there is a complex communication between bone cells and other organs, indicating the dynamic nature of bone tissue. In this review, we discuss the current data about the structure and functions of bone cells and the factors that influence bone remodeling. PMID:26247020

Structural pounding of concrete frame structure with masonry infill wall under seismic loading

NASA Astrophysics Data System (ADS)

Ismail, Rozaina; Hasnan, Mohd Hafizudin; Shamsudin, Nurhanis

2017-10-01

Structural pounding is additional problem than the other harmful damage that may occurs due to the earthquake vibrations. A lot of study has been made by past researcher but most of them did not include the walls. The infill masonry walls are rarely involved analysis of structural systems but it does contribute to earthquake response of the structures. In this research, a comparison between adjacent building of 10-storey and 7-storey concrete frame structure without of masonry infill walls and the same dynamic properties of buildings. The diagonal strut approach is adopted for modeling masonry infill walls. This research also focused on finding critical building separation in order to prevent the adjacent structures from pounding. LUSAS FEA v14.03 software has been used for modeling analyzing the behavior of structures due to seismic loading and the displacement each floor of the building has been taken in order to determine the critical separation distance between the buildings. From the analysis that has been done, it is found that masonry infill walls do affect the structures behavior under seismic load. Structures without masonry infill walls needs more distance between the structures to prevent structural pounding due to higher displacement of the buildings when it sways under seismic load compared to structures with masonry infill walls. This shows that contribution of masonry infill walls to the analysis of structures cannot be neglected.

A Multidimensional Approach to Understanding Under-Eating in Homebound Older Adults: The Importance of Social Factors

PubMed Central

Locher, Julie L.; Ritchie, Christine S.; Robinson, Caroline O.; Roth, David L.; West, Delia Smith; Burgio, Kathryn L.

2009-01-01

Purpose The purpose of this study was to identify relationships between medical, functional, economic, oral health, social, religious, and psychological factors and under-eating in homebound older adults. The focus of the study was on identifying potentially modifiable factors amenable to social and behavioral interventions. Design and Methods A total of 230 homebound older adults who were currently receiving home health services participated in interviews in their homes using a questionnaire to assess eating behaviors and factors that could possibly affect those eating behaviors. Interviewers measured height and weight, and participants completed three 24-hr dietary recalls. Results The mean age of participants was 79.1 years. The sample comprised 78% women and 38% African Americans. We found that 70% of participants were under-eating, defined as not consuming enough calories to maintain their current body weight. Participants who were at higher risk of under-eating included men, those receiving either infrequent care or very frequent care by a caregiver, those who had been hospitalized prior to receipt of home health services, and those with a higher body mass index. Implications Findings from the study have implications for both practice and policy. Experts must develop evidence-based interventions targeted at under-eating in this particularly vulnerable and growing population of homebound older adults. This study provides an initial foundation for the development of targeted evidence-based behavioral nutritional interventions that are noninvasive and cost effective. PMID:18483434

Fracture of Structural Materials under Dynamic Loading

DTIC Science & Technology

1981-03-25

in character- izing the dynamic fracture resistance of materials, and in designing equipment and procedures for measuring dynamic fracture toughness...useful in assessing the safety of structures under dynamic loads, in characterizing the dyraamic fracture resistance of materials, and in designing ...I INTRODUCTION Structures used by the United States Air Force must be designed to resist catastrophic fracture when subjected ti dynamic loads. For

Protein local structure alignment under the discrete Fréchet distance.

PubMed

Zhu, Binhai

2007-12-01

Protein structure alignment is a fundamental problem in computational and structural biology. While there has been lots of experimental/heuristic methods and empirical results, very few results are known regarding the algorithmic/complexity aspects of the problem, especially on protein local structure alignment. A well-known measure to characterize the similarity of two polygonal chains is the famous Fréchet distance, and with the application of protein-related research, a related discrete Fréchet distance has been used recently. In this paper, following the recent work of Jiang et al. we investigate the protein local structural alignment problem using bounded discrete Fréchet distance. Given m proteins (or protein backbones, which are 3D polygonal chains), each of length O(n), our main results are summarized as follows: * If the number of proteins, m, is not part of the input, then the problem is NP-complete; moreover, under bounded discrete Fréchet distance it is NP-hard to approximate the maximum size common local structure within a factor of n(1-epsilon). These results hold both when all the proteins are static and when translation/rotation are allowed. * If the number of proteins, m, is a constant, then there is a polynomial time solution for the problem.

A single factor underlies the metabolic syndrome: a confirmatory factor analysis.

PubMed

Pladevall, Manel; Singal, Bonita; Williams, L Keoki; Brotons, Carlos; Guyer, Heidi; Sadurni, Josep; Falces, Carles; Serrano-Rios, Manuel; Gabriel, Rafael; Shaw, Jonathan E; Zimmet, Paul Z; Haffner, Steven

2006-01-01

Confirmatory factor analysis (CFA) was used to test the hypothesis that the components of the metabolic syndrome are manifestations of a single common factor. Three different datasets were used to test and validate the model. The Spanish and Mauritian studies included 207 men and 203 women and 1,411 men and 1,650 women, respectively. A third analytical dataset including 847 men was obtained from a previously published CFA of a U.S. population. The one-factor model included the metabolic syndrome core components (central obesity, insulin resistance, blood pressure, and lipid measurements). We also tested an expanded one-factor model that included uric acid and leptin levels. Finally, we used CFA to compare the goodness of fit of one-factor models with the fit of two previously published four-factor models. The simplest one-factor model showed the best goodness-of-fit indexes (comparative fit index 1, root mean-square error of approximation 0.00). Comparisons of one-factor with four-factor models in the three datasets favored the one-factor model structure. The selection of variables to represent the different metabolic syndrome components and model specification explained why previous exploratory and confirmatory factor analysis, respectively, failed to identify a single factor for the metabolic syndrome. These analyses support the current clinical definition of the metabolic syndrome, as well as the existence of a single factor that links all of the core components.

Habitat and landscape characteristics underlying anuran community structure along an urban-rural gradient.

PubMed

Pillsbury, Finn C; Miller, James R

2008-07-01

Urbanization has been cited as an important factor in worldwide amphibian declines, and although recent work has illustrated the important influence of broad-scale ecological patterns and processes on amphibian populations, little is known about the factors structuring amphibian communities in urban landscapes. We therefore examined amphibian community responses to wetland habitat availability and landscape characteristics along an urban-rural gradient in central Iowa, USA, a region experiencing rapid suburban growth. We conducted call surveys at 61 wetlands to estimate anuran calling activity, and quantified wetland habitat structure and landscape context. We used canonical correspondence analysis (CCA) to examine patterns in anuran community structure and identify the most important variables associated with those patterns. Urban density at the landscape scale had a significant negative influence on overall anuran abundance and diversity. While every species exhibited a decrease in abundance with increasing urban density, this pattern was especially pronounced for species requiring post-breeding upland habitats. Anurans most affected by urbanization were those associated with short hydroperiods, early breeding activity, and substantial upland habitat use. We suggest that broad-scale landscape fragmentation is an important factor underlying anuran community structure in this region, possibly due to limitations on the accessibility of otherwise suitable habitat in fragmented urban landscapes. This study underscores the importance of a regional approach to amphibian conservation in urban and urbanizing areas; in fragmented landscapes, a network of interconnected wetland and upland habitats may be more likely to support a successful, diverse anuran community than will isolated sites.

Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility.

PubMed

Navarrete, Acacio Aparecido; Soares, Tielle; Rossetto, Raffaella; van Veen, Johannes Antonie; Tsai, Siu Mui; Kuramae, Eiko Eurya

2015-09-01

Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ("Management practices for sugarcane") disparate patterns were revealed in sugarcane rhizosphere sampled on optimal and deficient soil fertility for sugarcane (R = 0.786, P = 0.002). Verrucomicrobial community abundance in sugarcane rhizosphere was negatively correlated with soil fertility, accounting for 2 and 5 % of the total bacterial signal, under optimal and deficient soil fertility conditions for sugarcane, respectively. In nutrient-enriched soils, verrucomicrobial community structures were related to soil factors linked to soil fertility, such as total nitrogen, phosphorus, potassium and sum of bases, i.e., the sum of calcium, magnesium and potassium contents. We conclude that community structure and abundance represent important ecological aspects in soil verrucomicrobial communities for tracking the changes in chemical factors linked to soil fertility under tropical environmental conditions.

Electronic Structure of Energetic Molecules and Crystals Under Compression

NASA Astrophysics Data System (ADS)

Kay, Jeffrey

Understanding how the electronic structure of energetic materials change under compression is important to elucidating mechanisms of shock-induced reactions and detonation. In this presentation, the electronic structure of prototypical energetic crystals are examined under high degrees of compression using ab initio quantum chemical calculations. The effects of compression on and interactions between the constituent molecules are examined in particular. The insights these results provide into previous experimental observations and theoretical predictions of energetic materials under high pressure are 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. DOE's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Modulation of Endothelial Glycocalyx Structure under Inflammatory Conditions

PubMed Central

Kolářová, Hana; Ambrůzová, Barbora; Švihálková Šindlerová, Lenka; Klinke, Anna; Kubala, Lukáš

2014-01-01

The glycocalyx of the endothelium is an intravascular compartment that creates a barrier between circulating blood and the vessel wall. The glycocalyx is suggested to play an important role in numerous physiological processes including the regulation of vascular permeability, the prevention of the margination of blood cells to the vessel wall, and the transmission of shear stress. Various theoretical models and experimental approaches provide data about changes to the structure and functions of the glycocalyx under various types of inflammatory conditions. These alterations are suggested to promote inflammatory processes in vessels and contribute to the pathogenesis of number of diseases. In this review we summarize current knowledge about the modulation of the glycocalyx under inflammatory conditions and the consequences for the course of inflammation in vessels. The structure and functions of endothelial glycocalyx are briefly discussed in the context of methodological approaches regarding the determination of endothelial glycocalyx and the uncertainty and challenges involved in glycocalyx structure determination. In addition, the modulation of glycocalyx structure under inflammatory conditions and the possible consequences for pathogenesis of selected diseases and medical conditions (in particular, diabetes, atherosclerosis, ischemia/reperfusion, and sepsis) are summarized. Finally, therapeutic strategies to ameliorate glycocalyx dysfunction suggested by various authors are discussed. PMID:24803742

Further insights on the French WISC-IV factor structure through Bayesian structural equation modeling.

PubMed

Golay, Philippe; Reverte, Isabelle; Rossier, Jérôme; Favez, Nicolas; Lecerf, Thierry

2013-06-01

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 cross-loadings 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 concluded that the general factor should be considered as a breadth rather than a superordinate factor. Because it was possible for us to estimate the influence of each of the latent variables on the 15 subtest scores, BSEM allowed improvement of the understanding of the structure of intelligence tests and the clinical interpretation of the subtest scores. PsycINFO Database Record (c) 2013 APA, all rights reserved.

The promoter structure differentiation of a MYB transcription factor RLC1 causes red leaf coloration in Empire Red Leaf Cotton under light.

PubMed

Gao, Zhenrui; Liu, Chuanliang; Zhang, Yanzhao; Li, Ying; Yi, Keke; Zhao, Xinhua; Cui, Min-Long

2013-01-01

The red leaf coloration of Empire Red Leaf Cotton (ERLC) (Gossypium hirsutum L.), resulted from anthocyanin accumulation in light, is a well known dominant agricultural trait. However, the underpin molecular mechanism remains elusive. To explore this, we compared the molecular biological basis of anthocyanin accumulation in both ERLC and the green leaf cotton variety CCRI 24 (Gossypium hirsutum L.). Introduction of R2R3-MYB transcription factor Rosea1, the master regulator anthocyanin biosynthesis in Antirrhinum majus, into CCRI 24 induced anthocyanin accumulation, indicating structural genes for anthocyanin biosynthesis are not defected and the leaf coloration might be caused by variation of regulatory genes expression. Expression analysis found that a transcription factor RLC1 (Red Leaf Cotton 1) which encodes the ortholog of PAP1/Rosea1 was highly expressed in leaves of ERLC but barely expressed in CCRI 24 in light. Ectopic expression of RLC1 from ERLC and CCRI 24 in hairy roots of Antirrhinum majus and CCRI 24 significantly enhanced anthocyanin accumulation. Comparison of RLC1 promoter sequences between ERLC and CCRI 24 revealed two 228-bp tandem repeats presented in ERLC with only one repeat in CCRI 24. Transient assays in cotton leave tissue evidenced that the tandem repeats in ERLC is responsible for light-induced RLC1 expression and therefore anthocyanin accumulation. Taken together, our results in this article strongly support an important step toward understanding the role of R2R3-MYB transcription factors in the regulatory menchanisms of anthocyanin accumulation in red leaf cotton under light.

Latent structure modeling underlying theophylline tablet formulations using a Bayesian network based on a self-organizing map clustering.

PubMed

Yasuda, Akihito; Onuki, Yoshinori; Obata, Yasuko; Takayama, Kozo

2015-01-01

The "quality by design" concept in pharmaceutical formulation development requires the establishment of a science-based rationale and design space. In this article, we integrate thin-plate spline (TPS) interpolation, Kohonen's self-organizing map (SOM) and a Bayesian network (BN) to visualize the latent structure underlying causal factors and pharmaceutical responses. As a model pharmaceutical product, theophylline tablets were prepared using a standard formulation. We measured the tensile strength and disintegration time as response variables and the compressibility, cohesion and dispersibility of the pretableting blend as latent variables. We predicted these variables quantitatively using nonlinear TPS, generated a large amount of data on pretableting blends and tablets and clustered these data into several clusters using a SOM. Our results show that we are able to predict the experimental values of the latent and response variables with a high degree of accuracy and are able to classify the tablet data into several distinct clusters. In addition, to visualize the latent structure between the causal and latent factors and the response variables, we applied a BN method to the SOM clustering results. We found that despite having inserted latent variables between the causal factors and response variables, their relation is equivalent to the results for the SOM clustering, and thus we are able to explain the underlying latent structure. Consequently, this technique provides a better understanding of the relationships between causal factors and pharmaceutical responses in theophylline tablet formulation.

Contaminant deposition building shielding factors for US residential structures.

PubMed

Dickson, Elijah; Hamby, David; Eckerman, Keith

2017-10-10

This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario from contaminant deposition on the roof and surrounding surfaces. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations from contaminant deposition on the roof and surrounding ground as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement as well for single-wide manufactured housing-unit. © 2017 IOP Publishing Ltd.

Cloud immersion building shielding factors for US residential structures.

PubMed

Dickson, E D; Hamby, D M

2014-12-01

This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario within a semi-infinite cloud of radioactive material. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement, as well for single-wide manufactured housing-units.

Contaminant deposition building shielding factors for US residential structures.

PubMed

Dickson, E D; Hamby, D M; Eckerman, K F

2015-06-01

This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario from contaminant deposition on the roof and surrounding surfaces. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations from contaminant deposition on the roof and surrounding ground as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement as well for single-wide manufactured housing-unit.

Factor Structure of the Psychotherapy Supervisor Development Scale

ERIC Educational Resources Information Center

Barnes, Kristin L.; Moon, Simon M.

2006-01-01

The goodness of fit of 3 models of factor structure of the Psychotherapy Supervisor Development Scale (PSDS; C. E. Watkins, L. J. Schneider, J. Haynes, & R. Nieberding, 1995) were examined using a sample of counseling supervisors. The results indicated that the factor structure of the PSDS was largely consistent with the original 4-factor…

Investigation of structural factors of safety for the space shuttle

NASA Technical Reports Server (NTRS)

1972-01-01

A study was made of the factors governing the structural design of the fully reusable space shuttle booster to establish a rational approach to select optimum structural factors of safety. The study included trade studies of structural factors of safety versus booster service life, weight, cost, and reliability. Similar trade studies can be made on other vehicles using the procedures developed. The major structural components of a selected baseline booster were studied in depth, each being examined to determine the fatigue life, safe-life, and fail-safe capabilities of the baseline design. Each component was further examined to determine its reliability and safety requirements, and the change of structural weight with factors of safety. The apparent factors of safety resulting from fatigue, safe-life, proof test, and fail-safe requirements were identified. The feasibility of reduced factors of safety for design loads such as engine thrust, which are well defined, was examined.

Examining the factor structure of the Multiple Sclerosis Impact Scale.

PubMed

Fitzgerald, Shawn M; Li, Jian; Rumrill, Phillip D; Merchant, William; Bishop, Malachy

2014-01-01

The purpose of this study was to investigate the factor structure of the Multiple Sclerosis Impact Scale (MSIS-29) to assess its suitability for modeling the impact of MS on a nation-wide sample of individuals from the United States. Investigators completed a Confirmatory Factor Analysis (CFA) to examine the two-factor structure proposed by Hobart et al. [17]. Although the original MSIS-29 factor structure did not fit the data exactly, the hypothesized two-factor model was partially supported in the current data. Implications for future instrument development and rehabilitation practice are discussed.

Lack of congruence in species diversity indices and community structures of planktonic groups based on local environmental factors.

PubMed

Doi, Hideyuki; Chang, Kwang-Hyeon; Nishibe, Yuichiro; Imai, Hiroyuki; Nakano, Shin-ichi

2013-01-01

The importance of analyzing the determinants of biodiversity and community composition by using multiple trophic levels is well recognized; however, relevant data are lacking. In the present study, we investigated variations in species diversity indices and community structures of the plankton taxonomic groups-zooplankton, rotifers, ciliates, and phytoplankton-under a range of local environmental factors in pond ecosystems. For each planktonic group, we estimated the species diversity index by using linear models and analyzed the community structure by using canonical correspondence analysis. We showed that the species diversity indices and community structures varied among the planktonic groups and according to local environmental factors. The observed lack of congruence among the planktonic groups may have been caused by niche competition between groups with similar trophic guilds or by weak trophic interactions. Our findings highlight the difficulty of predicting total biodiversity within a system, based upon a single taxonomic group. Thus, to conserve the biodiversity of an ecosystem, it is crucial to consider variations in species diversity indices and community structures of different taxonomic groups, under a range of local conditions.

Temperate Mountain Forest Biodiversity under Climate Change: Compensating Negative Effects by Increasing Structural Complexity

PubMed Central

Braunisch, Veronika; Coppes, Joy; Arlettaz, Raphaël; Suchant, Rudi; Zellweger, Florian; Bollmann, Kurt

2014-01-01

Species adapted to cold-climatic mountain environments are expected to face a high risk of range contractions, if not local extinctions under climate change. Yet, the populations of many endothermic species may not be primarily affected by physiological constraints, but indirectly by climate-induced changes of habitat characteristics. In mountain forests, where vertebrate species largely depend on vegetation composition and structure, deteriorating habitat suitability may thus be mitigated or even compensated by habitat management aiming at compositional and structural enhancement. We tested this possibility using four cold-adapted bird species with complementary habitat requirements as model organisms. Based on species data and environmental information collected in 300 1-km2 grid cells distributed across four mountain ranges in central Europe, we investigated (1) how species’ occurrence is explained by climate, landscape, and vegetation, (2) to what extent climate change and climate-induced vegetation changes will affect habitat suitability, and (3) whether these changes could be compensated by adaptive habitat management. Species presence was modelled as a function of climate, landscape and vegetation variables under current climate; moreover, vegetation-climate relationships were assessed. The models were extrapolated to the climatic conditions of 2050, assuming the moderate IPCC-scenario A1B, and changes in species’ occurrence probability were quantified. Finally, we assessed the maximum increase in occurrence probability that could be achieved by modifying one or multiple vegetation variables under altered climate conditions. Climate variables contributed significantly to explaining species occurrence, and expected climatic changes, as well as climate-induced vegetation trends, decreased the occurrence probability of all four species, particularly at the low-altitudinal margins of their distribution. These effects could be partly compensated by modifying

Temperate mountain forest biodiversity under climate change: compensating negative effects by increasing structural complexity.

PubMed

Braunisch, Veronika; Coppes, Joy; Arlettaz, Raphaël; Suchant, Rudi; Zellweger, Florian; Bollmann, Kurt

2014-01-01

Species adapted to cold-climatic mountain environments are expected to face a high risk of range contractions, if not local extinctions under climate change. Yet, the populations of many endothermic species may not be primarily affected by physiological constraints, but indirectly by climate-induced changes of habitat characteristics. In mountain forests, where vertebrate species largely depend on vegetation composition and structure, deteriorating habitat suitability may thus be mitigated or even compensated by habitat management aiming at compositional and structural enhancement. We tested this possibility using four cold-adapted bird species with complementary habitat requirements as model organisms. Based on species data and environmental information collected in 300 1-km2 grid cells distributed across four mountain ranges in central Europe, we investigated (1) how species' occurrence is explained by climate, landscape, and vegetation, (2) to what extent climate change and climate-induced vegetation changes will affect habitat suitability, and (3) whether these changes could be compensated by adaptive habitat management. Species presence was modelled as a function of climate, landscape and vegetation variables under current climate; moreover, vegetation-climate relationships were assessed. The models were extrapolated to the climatic conditions of 2050, assuming the moderate IPCC-scenario A1B, and changes in species' occurrence probability were quantified. Finally, we assessed the maximum increase in occurrence probability that could be achieved by modifying one or multiple vegetation variables under altered climate conditions. Climate variables contributed significantly to explaining species occurrence, and expected climatic changes, as well as climate-induced vegetation trends, decreased the occurrence probability of all four species, particularly at the low-altitudinal margins of their distribution. These effects could be partly compensated by modifying

The R-factor gap in macromolecular crystallography: an untapped potential for insights on accurate structures.

PubMed

Holton, James M; Classen, Scott; Frankel, Kenneth A; Tainer, John A

2014-09-01

In macromolecular crystallography, the agreement between observed and predicted structure factors (Rcryst and Rfree ) is seldom better than 20%. This is much larger than the estimate of experimental error (Rmerge ). The difference between Rcryst and Rmerge is the R-factor gap. There is no such gap in small-molecule crystallography, for which calculated structure factors are generally considered more accurate than the experimental measurements. Perhaps the true noise level of macromolecular data is higher than expected? Or is the gap caused by inaccurate phases that trap refined models in local minima? By generating simulated diffraction patterns using the program MLFSOM, and including every conceivable source of experimental error, we show that neither is the case. Processing our simulated data yielded values that were indistinguishable from those of real data for all crystallographic statistics except the final Rcryst and Rfree . These values decreased to 3.8% and 5.5% for simulated data, suggesting that the reason for high R-factors in macromolecular crystallography is neither experimental error nor phase bias, but rather an underlying inadequacy in the models used to explain our observations. The present inability to accurately represent the entire macromolecule with both its flexibility and its protein-solvent interface may be improved by synergies between small-angle X-ray scattering, computational chemistry and crystallography. The exciting implication of our finding is that macromolecular data contain substantial hidden and untapped potential to resolve ambiguities in the true nature of the nanoscale, a task that the second century of crystallography promises to fulfill. Coordinates and structure factors for the real data have been submitted to the Protein Data Bank under accession 4tws. © 2014 The Authors. FEBS Journal published by John Wiley & Sons Ltd on behalf of FEBS.

The underlying structure of diagnostic systems of schizophrenia: a comprehensive polydiagnostic approach.

PubMed

Peralta, Victor; Cuesta, Manuel J

2005-11-15

The objective was to ascertain the underlying factor structure of alternative definitions of schizophrenia, and to examine the distribution of schizophrenia-related variables against the resulting factor solution. Twenty-three diagnostic schemes of schizophrenia were applied to 660 patients presenting with psychotic symptoms regardless of the specific diagnosis of psychotic disorder. Factor analysis of the 23 diagnostic schemes yielded three interpretable factors explaining 58% of the variance, the first factor (general schizophrenia factor) accounting for most of the variance (36%). On the basis of the general schizophrenia factor score, the sample was divided in quintile groups representing 5 levels of schizophrenia definition (absent, doubtful, very broad, broad and narrow) and the distribution of a number of schizophrenia-related variables was examined across the groups. This grouping procedure was used for examining the comparative validity of alternative levels of categorically defined schizophrenia and an ordinal (i.e. dimensional) definition. Overall, schizophrenia-related variables displayed a dose-response relationship with level of schizophrenia definition. Logistic regression analyses revealed that the dimensional definition explained more variance in the schizophrenia-related variables than the alternative levels for defining schizophrenia categorically. These results are consistent with a unitary and dimensional construct of schizophrenia with no clear "points of rarity" at its boundaries, thus supporting the continuum hypothesis of the psychotic illness.

Flexural creep of structural flakeboards under cyclic humidity

Treesearch

M.C. Yeh; R.C. Tang; Chung-Yun Hse

1990-01-01

Flexural creep behavior of randomly oriented structural flakeboards under cyclic humidity is presented. Specimens fabricated with 5 and 7 percent phenol-formaldehyde resin were subjected to constant concentrated load in bending under slow and fast cyclic relative humidity (RH) between 65 and 95 percent for 100 days. The temperature was set at a constant 75°F through...

Anatomical Thin Titanium Mesh Plate Structural Optimization for Zygomatic-Maxillary Complex Fracture under Fatigue Testing.

PubMed

Wang, Yu-Tzu; Huang, Shao-Fu; Fang, Yu-Ting; Huang, Shou-Chieh; Cheng, Hwei-Fang; Chen, Chih-Hao; Wang, Po-Fang; Lin, Chun-Li

2018-01-01

This study performs a structural optimization of anatomical thin titanium mesh (ATTM) plate and optimal designed ATTM plate fabricated using additive manufacturing (AM) to verify its stabilization under fatigue testing. Finite element (FE) analysis was used to simulate the structural bending resistance of a regular ATTM plate. The Taguchi method was employed to identify the significance of each design factor in controlling the deflection and determine an optimal combination of designed factors. The optimal designed ATTM plate with patient-matched facial contour was fabricated using AM and applied to a ZMC comminuted fracture to evaluate the resting maxillary micromotion/strain under fatigue testing. The Taguchi analysis found that the ATTM plate required a designed internal hole distance to be 0.9 mm, internal hole diameter to be 1 mm, plate thickness to be 0.8 mm, and plate height to be 10 mm. The designed plate thickness factor primarily dominated the bending resistance up to 78% importance. The averaged micromotion (displacement) and strain of the maxillary bone showed that ZMC fracture fixation using the miniplate was significantly higher than those using the AM optimal designed ATTM plate. This study concluded that the optimal designed ATTM plate with enough strength to resist the bending effect can be obtained by combining FE and Taguchi analyses. The optimal designed ATTM plate with patient-matched facial contour fabricated using AM provides superior stabilization for ZMC comminuted fractured bone segments.

Why are you draining your brain? Factors underlying decisions of graduating Lebanese medical students to migrate.

PubMed

Akl, Elie A; Maroun, Nancy; Major, Stella; Afif, Claude; Chahoud, Bechara; Choucair, Jacques; Sakr, Mazen; Schünemann, Holger J

2007-03-01

In the context of a worldwide physician brain drain phenomenon, Lebanon has the highest emigration factor in the Middle East and North Africa. In this manuscript we aim to identify and develop a conceptual framework for the factors underlying the decisions of graduating Lebanese medical students to train abroad. We conducted two focus groups and seven semi-structured individual interviews with 23 students. In the deductive analysis (based on the push-pull theory), students reported push factors in Lebanon and pull factors abroad related to five dimensions. They focused predominantly on how training abroad provides them with a competitive advantage in an oversaturated Lebanese job market. An inductive analysis revealed the following emerging concepts: repel factors abroad and retain factors locally; societal expectations that students should train abroad; marketing of abroad training; and an established culture of migration. The marketing of abroad training and the culture of migration are prevalent in the academic institutions.

Structural stability of bismuth-based superconductors under heterovalent substitution

NASA Astrophysics Data System (ADS)

Bonoldi, L.; Calestani, G. L.; Francesconi, M. G.; Salsi, G.; Sparpaglione, M.; Zini, L.

1995-02-01

The stability of the three CuO 2 layers phase of BiPbSrCaCuO superconducting system (BSCCO) with the addition of several rare-earth (RE) oxides is considered. It is shown that if a trivalent (Y, Nd, Gd, Dy, Ho, Er) or tetravalent (Ce) cation is nominally substituted “ab initio” on the Ca site, the higher- Tc phase of this system (the 2223 phase) does not form, at least for dopant molar concentration larger than or equal to 0.032 in the nominal formula of the 2223 phase. If RE oxides are added to a preformed 2223, a solid-state reaction at a temperature of about 840°C takes place giving rise to a substituted (Bi 2- yPb y)Sr 2Ca 1- xRE xCu 2O 8 compound plus other oxides. The synthesis of RE doped 2223 phase was attempted in different ways without success. We argue that this is due to thermodynamic rather than kinetic factors. A possible explanation of 2223 instability under doping in the calcium site with a higher-valence ion is proposed. It highlights the difference with the Bi 2Sr 2CaCu 2O 8 structural stability under the same doping conditions.

Tree-Structured Infinite Sparse Factor Model

PubMed Central

Zhang, XianXing; Dunson, David B.; Carin, Lawrence

2013-01-01

A tree-structured multiplicative gamma process (TMGP) is developed, for inferring the depth of a tree-based factor-analysis model. This new model is coupled with the nested Chinese restaurant process, to nonparametrically infer the depth and width (structure) of the tree. In addition to developing the model, theoretical properties of the TMGP are addressed, and a novel MCMC sampler is developed. The structure of the inferred tree is used to learn relationships between high-dimensional data, and the model is also applied to compressive sensing and interpolation of incomplete images. PMID:25279389

How large B-factors can be in protein crystal structures.

PubMed

Carugo, Oliviero

2018-02-23

Protein crystal structures are potentially over-interpreted since they are routinely refined without any restraint on the upper limit of atomic B-factors. Consequently, some of their atoms, undetected in the electron density maps, are allowed to reach extremely large B-factors, even above 100 square Angstroms, and their final positions are purely speculative and not based on any experimental evidence. A strategy to define B-factors upper limits is described here, based on the analysis of protein crystal structures deposited in the Protein Data Bank prior 2008, when the tendency to allow B-factor to arbitrary inflate was limited. This B-factor upper limit (B_max) is determined by extrapolating the relationship between crystal structure average B-factor and percentage of crystal volume occupied by solvent (pcVol) to pcVol =100%, when, ab absurdo, the crystal contains only liquid solvent, the structure of which is, by definition, undetectable in electron density maps. It is thus possible to highlight structures with average B-factors larger than B_max, which should be considered with caution by the users of the information deposited in the Protein Data Bank, in order to avoid scientifically deleterious over-interpretations.

Automated processing of first-pass radionuclide angiocardiography by factor analysis of dynamic structures.

PubMed

Cavailloles, F; Bazin, J P; Capderou, A; Valette, H; Herbert, J L; Di Paola, R

1987-05-01

structure (underlying physiological components), and the associated factor images are estimates of the spatial distribution of each factor. The aim of this study was to assess the reliability of FADS in first pass RNA and compare the results to those obtained by the ROI method which is generally considered as the routine procedure.

Electronic and structural properties of Lu under pressure: Relation to structural phases of the rare-earth metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Min, B.I.; Oguchi, T.; Jansen, H.J.F.

1986-07-15

Ground-state electronic and structural properties of Lu under pressure are investigated with use of the self-consistent all-electron total-energy linear muffin-tin orbital band-structure method within a local-density-functional approximation. Pressure-induced structural transitions are found to occur in the following sequence: hcp--(Sm-type)--dhcp--fcc, which is the same as that observed in the crystal structures of the trivalent rare-earth metals with decreasing atomic number. This structural transition is correlated with the increase in the number of d-italic electrons under pressure.

NUTRITIONAL STATUS AND ASSOCIATED FACTORS IN UNDER-FIVE CHILDREN OF RAWALPINDI.

PubMed

Mahmood, Shafaq; Nadeem, Sehrish; Saif, Tayyaba; Mannan, Mavra; Arshad, Urooj

2016-01-01

Malnutrition is a serious child health issue throughout the developing world. Pakistan has the second highest infant and child mortality rate in South Asia. This study was carried out to assess the nutritional status of children under 5 years of age and to determine the frequency and association of malnutrition with various demographic variables in the study group. A multi-centre, cross sectional study was conducted at the immunization centres of the 3 allied hospitals of Rawalpindi Medical College during March-May 2014. Healthy children of under 5 years of age without confirmed diagnosis of any disease/ailment were included. Guardians of 100 children were interviewed using a structured questionnaire. Demographic variables include age, gender, family size, family income, breastfeeding, maternal education, presence of a family member with special needs and presence of siblings under 5 years in family. Weight (kg) was measured and malnutrition was assessed by weight for age. Malnutrition was found to be present in 32% of children. Adequately nourished children were 68%, while moderately and severely malnourished children were 14% and 18% respectively. Our study indicated malnutrition to be significantly associated with maternal illiteracy (p = 0.01) and presence of a family member with special needs (p = 0.05). No significant association was found between malnutrition and gender, family size, family income, breast feeding and presence of siblings under 5 years of age. There is a need to plan composite interventions to elucidate the factors that place children at greater risk for malnutrition.

Probabilistic simulation of the human factor in structural reliability

NASA Technical Reports Server (NTRS)

Shah, Ashwin R.; Chamis, Christos C.

1991-01-01

Many structural failures have occasionally been attributed to human factors in engineering design, analyses maintenance, and fabrication processes. Every facet of the engineering process is heavily governed by human factors and the degree of uncertainty associated with them. Factors such as societal, physical, professional, psychological, and many others introduce uncertainties that significantly influence the reliability of human performance. Quantifying human factors and associated uncertainties in structural reliability require: (1) identification of the fundamental factors that influence human performance, and (2) models to describe the interaction of these factors. An approach is being developed to quantify the uncertainties associated with the human performance. This approach consists of a multi factor model in conjunction with direct Monte-Carlo simulation.

Improving the Factor Structure of Psychological Scales

PubMed Central

Zhang, Xijuan; Savalei, Victoria

2015-01-01

Many psychological scales written in the Likert format include reverse worded (RW) items in order to control acquiescence bias. However, studies have shown that RW items often contaminate the factor structure of the scale by creating one or more method factors. The present study examines an alternative scale format, called the Expanded format, which replaces each response option in the Likert scale with a full sentence. We hypothesized that this format would result in a cleaner factor structure as compared with the Likert format. We tested this hypothesis on three popular psychological scales: the Rosenberg Self-Esteem scale, the Conscientiousness subscale of the Big Five Inventory, and the Beck Depression Inventory II. Scales in both formats showed comparable reliabilities. However, scales in the Expanded format had better (i.e., lower and more theoretically defensible) dimensionalities than scales in the Likert format, as assessed by both exploratory factor analyses and confirmatory factor analyses. We encourage further study and wider use of the Expanded format, particularly when a scale’s dimensionality is of theoretical interest. PMID:27182074

Factor structure of the Body Appreciation Scale among Malaysian women.

PubMed

Swami, Viren; Chamorro-Premuzic, Tomas

2008-12-01

The present study examined the factor structure of a Malay version of the Body Appreciation Scale (BAS), a recently developed scale for the assessment of positive body image that has been shown to have a unidimensional structure in Western settings. Results of exploratory and confirmatory factor analyses based on data from community sample of 591 women in Kuala Lumpur, Malaysia, failed to support a unidimensional structure for the Malay BAS. Results of a confirmatory factor analysis suggested two stable factors, which were labelled 'General Body Appreciation' and 'Body Image Investment'. Multi-group analysis showed that the two-factor structure was invariant for both Malaysian Malay and Chinese women, and that there were no significant ethnic differences on either factor. Results also showed that General Body Appreciation was significant negatively correlated with participants' body mass index. These results are discussed in relation to possible cross-cultural differences in positive body image.

Factor Scores, Structure Coefficients, and Communality Coefficients

ERIC Educational Resources Information Center

Goodwyn, Fara

2012-01-01

This paper presents heuristic explanations of factor scores, structure coefficients, and communality coefficients. Common misconceptions regarding these topics are clarified. In addition, (a) the regression (b) Bartlett, (c) Anderson-Rubin, and (d) Thompson methods for calculating factor scores are reviewed. Syntax necessary to execute all four…

Factor Structure of the Exercise Self-Efficacy Scale

ERIC Educational Resources Information Center

Cornick, Jessica E.

2015-01-01

The current study utilized exercise self-efficacy ratings from undergraduate students to assess the factor structure of the Self-Efficacy to Regulate Exercise Scale (Bandura, 1997, 2006). An exploratory factor analysis (n = 759) indicated a two-factor model solution and three separate confirmatory factor analyses (n = 1,798) supported this…

Temperature and composition dependence of Mg-based amorphous-alloy structure factors

NASA Astrophysics Data System (ADS)

From, M.; Muir, W. B.

1992-01-01

Measurements of the x-ray total structure factors for amorphous Mg70Zn30, Ca70Mg30, and Mg85.5Cu14.5 at 9, 150, and 300 K have been made. The composition dependence of the room-temperature structure factors of MgxZn1-x have also been measured for values of x=0.65, 0.70, and 0.75. These compositional changes can be accounted for by the increase in average atomic size as the fraction of the larger Mg atoms increases with x. Also the Perkus-Yevick hard-sphere model is sufficient to calculate the change in structure factor with composition if an experimental structure factor is available from which the sphere diameters and packing fraction can be extracted. The temperature dependence of the structure factors is consistent with the observed thermal expansion and a Debye phonon model with Meisel and Cote's approximation for the multiphonon contribution to the structure factor.

Fault-tolerant control of large space structures using the stable factorization approach

NASA Technical Reports Server (NTRS)

Razavi, H. C.; Mehra, R. K.; Vidyasagar, M.

1986-01-01

Large space structures are characterized by the following features: they are in general infinite-dimensional systems, and have large numbers of undamped or lightly damped poles. Any attempt to apply linear control theory to large space structures must therefore take into account these features. Phase I consisted of an attempt to apply the recently developed Stable Factorization (SF) design philosophy to problems of large space structures, with particular attention to the aspects of robustness and fault tolerance. The final report on the Phase I effort consists of four sections, each devoted to one task. The first three sections report theoretical results, while the last consists of a design example. Significant results were obtained in all four tasks of the project. More specifically, an innovative approach to order reduction was obtained, stabilizing controller structures for plants with an infinite number of unstable poles were determined under some conditions, conditions for simultaneous stabilizability of an infinite number of plants were explored, and a fault tolerance controller design that stabilizes a flexible structure model was obtained which is robust against one failure condition.

Quantification of site-city interaction effects on the response of structure under double resonance condition

NASA Astrophysics Data System (ADS)

Kumar, Neeraj; Narayan, Jay Prakash

2018-01-01

This paper presents the site-city interaction (SCI) effects on the response of closely spaced structures under double resonance condition (F_{02{{D}}}^{{S}} = F_{02{{D}}}^{{B}}), where F_{02{{D}}}^{{S}} and F_{02{{D}}}^{{B}} are fundamental frequencies of 2-D structure and 2-D basin, respectively. This paper also presents the development of empirical relations to predict the F_{02{{D}}}^{{B}} of elliptical and trapezoidal basins for both the polarizations of the S wave. Simulated results revealed that F_{02{{D}}}^{{B}} of a 2-D basin very much depends on its geometry, shape ratio and polarization of the incident S wave. The obtained spectral amplification factor (SAF) at F_{02{{D}}}^{{S}} of a standalone structure in a 2-D basin is greater than that in the 1-D case under double resonance condition. A considerable reduction of the fundamental resonance frequency of structures due to the SCI effects is observed for both the polarizations of the S wave. The SAFs at F_{02{{D}}}^{{S}} of closely spaced structures due to SCI effects is larger in the case of SV than SH waves. A splitting of the fundamental-mode frequency bandwidth along with the drastic decrease of SAF due to the SCI effects is obtained. The findings of this paper raise the question concerning the validity of the predicted response of standalone structure based on soil-structure interaction for the design of structures in a 2-D small basin, in an urban environment.

The structure factor of primes

NASA Astrophysics Data System (ADS)

Zhang, G.; Martelli, F.; Torquato, S.

2018-03-01

Although the prime numbers are deterministic, they can be viewed, by some measures, as pseudo-random numbers. In this article, we numerically study the pair statistics of the primes using statistical-mechanical methods, particularly the structure factor S(k) in an interval M ≤slant p ≤slant M + L with M large, and L/M smaller than unity. We show that the structure factor of the prime-number configurations in such intervals exhibits well-defined Bragg-like peaks along with a small ‘diffuse’ contribution. This indicates that primes are appreciably more correlated and ordered than previously thought. Our numerical results definitively suggest an explicit formula for the locations and heights of the peaks. This formula predicts infinitely many peaks in any non-zero interval, similar to the behavior of quasicrystals. However, primes differ from quasicrystals in that the ratio between the location of any two predicted peaks is rational. We also show numerically that the diffuse part decays slowly as M and L increases. This suggests that the diffuse part vanishes in an appropriate infinite-system-size limit.

Dynamic response analysis of structure under time-variant interval process model

NASA Astrophysics Data System (ADS)

Xia, Baizhan; Qin, Yuan; Yu, Dejie; Jiang, Chao

2016-10-01

Due to the aggressiveness of the environmental factor, the variation of the dynamic load, the degeneration of the material property and the wear of the machine surface, parameters related with the structure are distinctly time-variant. Typical model for time-variant uncertainties is the random process model which is constructed on the basis of a large number of samples. In this work, we propose a time-variant interval process model which can be effectively used to deal with time-variant uncertainties with limit information. And then two methods are presented for the dynamic response analysis of the structure under the time-variant interval process model. The first one is the direct Monte Carlo method (DMCM) whose computational burden is relative high. The second one is the Monte Carlo method based on the Chebyshev polynomial expansion (MCM-CPE) whose computational efficiency is high. In MCM-CPE, the dynamic response of the structure is approximated by the Chebyshev polynomials which can be efficiently calculated, and then the variational range of the dynamic response is estimated according to the samples yielded by the Monte Carlo method. To solve the dependency phenomenon of the interval operation, the affine arithmetic is integrated into the Chebyshev polynomial expansion. The computational effectiveness and efficiency of MCM-CPE is verified by two numerical examples, including a spring-mass-damper system and a shell structure.

Substance abuse, violence, HIV, and depression: an underlying syndemic factor among Latinas.

PubMed

González-Guarda, Rosa Maria; McCabe, Brian E; Florom-Smith, Aubrey; Cianelli, Rosina; Peragallo, Nilda

2011-01-01

Evidence from the literature suggests that substance abuse, violence, HIV risk, depressive symptoms, and underlying socioeconomic conditions are tied intrinsically to health disparities among Latinas. Although these health and social conditions appear to comprise a syndemic, an underlying phenomenon disproportionately accounting for the burden of disease among marginalized groups, these hypothesized relationships have not been formally tested. The aim of this study was to assess (a) if substance abuse, violence, HIV risk, and depressive symptoms comprised a syndemic and (b) if this syndemic was related to socioeconomic disadvantage among Latinas. Baseline assessment data from a randomized controlled community trial testing the efficacy of an HIV risk reduction program for adult Latinas (n = 548) were used to measure demographic variables, substance abuse, violence, risk for HIV, and depressive symptoms. Structural equation modeling was used to test a single underlying syndemic factor model and any relation to socioeconomic disadvantage. The results of this study support the idea that HIV risk, substance abuse, violence, and depressive symptoms comprise a syndemic, χ(27) = 53.26, p < .01 (relative χ = 1.97, comparative fit index = .91, root mean square error of approximation = .04). In addition, in limited accord with theory, this factor was related to 2 measures of socioeconomic disadvantage, percentage of years in the United States (b = 7.55, SE = 1.53, p < .001) and education (b = -1.98, SE = .87, p < .05). The results of this study could be used to guide public health programs and policies targeting behavioral health disparity conditions among Latinos and other vulnerable populations. Further study of the influence of gender-role expectations and community-level socioeconomic indicators may provide additional insight into this syndemic.

Rationalizing the role of structural motif and underlying electronic structure in the finite temperature behavior of atomic clusters

NASA Astrophysics Data System (ADS)

Susan, Anju; Joshi, Kavita

2014-04-01

Melting in finite size systems is an interesting but complex phenomenon. Many factors affect melting and owing to their interdependencies it is a challenging task to rationalize their roles in the phase transition. In this work, we demonstrate how structural motif of the ground state influences melting transition in small clusters. Here, we report a case with clusters of aluminum and gallium having same number of atoms, valence electrons, and similar structural motif of the ground state but drastically different melting temperatures. We have employed Born-Oppenheimer molecular dynamics to simulate the solid-like to liquid-like transition in these clusters. Our simulations have reproduced the experimental trends fairly well. Further, the detailed analysis of isomers has brought out the role of the ground state structure and underlying electronic structure in the finite temperature behavior of these clusters. For both clusters, isomers accessible before cluster melts have striking similarities and does have strong influence of the structural motif of the ground state. Further, the shape of the heat capacity curve is similar in both the cases but the transition is more spread over for Al36 which is consistent with the observed isomerization pattern. Our simulations also suggest a way to characterize transition region on the basis of accessibility of the ground state at a specific temperature.

Assessing Protective Factors for Violence Risk in U.K. General Mental Health Services Using the Structured Assessment of Protective Factors.

PubMed

Haines, Alina; Brown, Andrew; Javaid, Syed Fahad; Khan, Fayyaz; Noblett, Steve; Omodunbi, Oladipupo; Sadiq, Khurram; Zaman, Wahid; Whittington, Richard

2017-12-01

Violence risk assessment and management are key tasks in mental health services and should be guided by validated instruments covering both risk and protective factors. This article is part of an international effort to validate the Structured Assessment of Protective Factors (SAPROF) for violence. The SAPROF, Historical, Clinical, Risk Management-20 (HCR-20) and the Psychopathy Checklist-Screening Version (PCL-SV) were administered in a sample of 261 patients in U.K. forensic, general inpatient, and community mental health settings. There was significant variation between these groups on SAPROF scores with fewer protective factors in the forensic group. The prospective validity of the SAPROF for nonviolence in the general inpatient and community samples was moderate (area under the curve [AUC] = .60). Adoption of the SAPROF or similar instruments as a supplement to risk-focused assessments has the potential to improve awareness of protective factors and enhance therapeutic engagement in a range of mental health services.

Investigations on the Mechanical Properties of Conducting Polymer Coating-Substrate Structures and Their Influencing Factors

PubMed Central

Wang, Xi-Shu; Tang, Hua-Ping; Li, Xu-Dong; Hua, Xin

2009-01-01

This review covers recent advances and work on the microstructure features, mechanical properties and cracking processes of conducting polymer film/coating- substrate structures under different testing conditions. An attempt is made to characterize and quantify the relationships between mechanical properties and microstructure features. In addition, the film cracking mechanism on the micro scale and some influencing factors that play a significant role in the service of the film-substrate structure are presented. These investigations cover the conducting polymer film/coating nucleation process, microstructure-fracture characterization, translation of brittle-ductile fractures, and cracking processes near the largest inherent macromolecule defects under thermal-mechanical loadings, and were carried out using in situ scanning electron microscopy (SEM) observations, as a novel method for evaluation of interface strength and critical failure stress. PMID:20054470

Structural health management of aerospace hotspots under fatigue loading

NASA Astrophysics Data System (ADS)

Soni, Sunilkumar

Sustainability and life-cycle assessments of aerospace systems, such as aircraft structures and propulsion systems, represent growing challenges in engineering. Hence, there has been an increasing demand in using structural health monitoring (SHM) techniques for continuous monitoring of these systems in an effort to improve safety and reduce maintenance costs. The current research is part of an ongoing multidisciplinary effort to develop a robust SHM framework resulting in improved models for damage-state awareness and life prediction, and enhancing capability of future aircraft systems. Lug joints, a typical structural hotspot, were chosen as the test article for the current study. The thesis focuses on integrated SHM techniques for damage detection and characterization in lug joints. Piezoelectric wafer sensors (PZTs) are used to generate guided Lamb waves as they can be easily used for onboard applications. Sensor placement in certain regions of a structural component is not feasible due to the inaccessibility of the area to be monitored. Therefore, a virtual sensing concept is introduced to acquire sensor data from finite element (FE) models. A full three dimensional FE analysis of lug joints with piezoelectric transducers, accounting for piezoelectrical-mechanical coupling, was performed in Abaqus and the sensor signals were simulated. These modeled sensors are called virtual sensors. A combination of real data from PZTs and virtual sensing data from FE analysis is used to monitor and detect fatigue damage in aluminum lug joints. Experiments were conducted on lug joints under fatigue loads and sensor signals collected were used to validate the simulated sensor response. An optimal sensor placement methodology for lug joints is developed based on a detection theory framework to maximize the detection rate and minimize the false alarm rate. The placement technique is such that the sensor features can be directly correlated to damage. The technique accounts for a

The Construct Validity of Higher Order Structure-of-Intellect Abilities in a Battery of Tests Emphasizing the Product of Transformations: A Confirmatory Maximum Likelihood Factor Analysis.

ERIC Educational Resources Information Center

Khattab, Ali-Maher; And Others

1982-01-01

A causal modeling system, using confirmatory maximum likelihood factor analysis with the LISREL IV computer program, evaluated the construct validity underlying the higher order factor structure of a given correlation matrix of 46 structure-of-intellect tests emphasizing the product of transformations. (Author/PN)

Factor Structure and Reliability of the Parent-Informant Strengths and Difficulties Questionnaire in a Scottish Preschool Sample

ERIC Educational Resources Information Center

McAloney-Kocaman, Kareena; McPherson, Kerri

2017-01-01

Research Findings: Despite it being a widely accepted measure of social, emotional, and behavioral problems among children and young people, the factor structure underlying the Strengths and Difficulties Questionnaire (SDQ) is contested. Recent research has suggested a need to consider methodological bias in the SDQ, associated with the positive…

Buckling of Thermoviscoelastic Structures Under Temporal and Spatial Temperature Variations

NASA Technical Reports Server (NTRS)

Tsuyuki, Richard; Knauss, Wolfgang G.

1992-01-01

The problem of lateral instability of a viscoelastic in-plane loaded structure is considered in terms of thermorheolgically simple materials. As an example of a generally in-plane loaded structure, we examine the simple column under axial load: Both cyclic loading is considered (with constant or in-phase variable temperature excursions) as well as the case of constant load in the presence of thermal gradients through the thickness of the structure. The latter case involves a continuous movement of the neutral axis from the center to the colder side and then back to the center. In both cases, temperature has a very strong effect on the instability evolution, and under in-phase thermal cycling the critical loads are reduced compared to those at constant temperatures. The primary effect of thermal gradients beyond that of thermally-induced rate accelerations is occasioned by the generation of an "initial imperfection" or "structural bowing." Because the coefficient of thermal expansion tends to be large for many polymeric materials, it it may be necessary to take special care in lay-up design of composite structures intended for use under compressive loads in high-temperature applications. Finally, the implications for the temperature sensitivities of composites to micro-instability (fiber crimping) are also apparent from the results delineated here.

Resizing procedure for structures under combined mechanical and thermal loading

NASA Technical Reports Server (NTRS)

Adelman, H. M.; Narayanaswami, R.

1976-01-01

The fully-stressed design (FSD) appears to be the most widely used approach for sizing of flight structures under strength and minimum-gage constraints. Almost all of the experience with FSD has been with structures primarily under mechanical loading as opposed to thermal loading. In this method the structural sizes are iterated with the step size, depending on the ratio of the total stress to the allowable stress. In this paper, the thermal fully-stressed design (TFSD) procedure developed for problems involving substantial thermal stress is extended to biaxial stress members using a Von Mises failure criterion. The TFSD resizing procedure for uniaxial stress is restated and the new procedure for biaxial stress members is developed. Results are presented for an application of the two procedures to size a simplified wing structure.

Factor structure of a standards-based inventory of competencies in social work with groups.

PubMed

Macgowan, Mark J; Dillon, Frank R; Spadola, Christine E

2018-01-01

This study extends previous findings on a measure of competencies based on Standards for Social Work Practice with Groups. The Inventory of Competencies in Social Work with Groups (ICSWG) measures confidence in performing the Standards. This study examines the latent structure of the Inventory, while illuminating the underlying structure of the Standards. A multinational sample of 586 persons completed the ICSWG. Exploratory factor analysis (EFA), reliability estimates, standard error of measurement estimates, and a range of validity tests were conducted. The EFA yielded a six-factor solution consisting of core values, mutuality/connectivity, collaboration, and three phases of group development (planning, beginnings/middles, endings). The alphas were .98 for the scale and ranged from .85 to .95 for the subscales. Correlations between the subscales and validators supported evidence of construct validity. The findings suggest key group work domains that should be taught and practiced in social work with groups.

The Genetic and Environmental Factors Underlying Hypospadias

PubMed Central

Pask, Andrew; Heloury, Yves; Sinclair, Andrew H.

2016-01-01

Hypospadias results from a failure of urethral closure in the male phallus and affects 1 in 200–300 boys. It is thought to be due to a combination of genetic and environmental factors. The development of the penis progresses in 2 stages: an initial hormone-independent phase and a secondary hormone-dependent phase. Here, we review the molecular pathways that contribute to each of these stages, drawing on studies from both human and mouse models. Hypospadias can occur when normal development of the phallus is disrupted, and we provide evidence that mutations in genes underlying this developmental process are causative. Finally, we discuss the environmental factors that may contribute to hypospadias and their potential immediate and transgen erational epigenetic impacts. PMID:26613581

A factor analysis of landscape pattern and structure metrics

Treesearch

Kurt H. Riitters; R.V. O' Neill; C.T. Hunsaker; James D. Wickham; D.H. Yankee; S.P. Timmins; K.B. Jones; B.L. Jackson

1995-01-01

Fifty-five metrics of landscape pattern and structure were calculated for 85 maps of land use and land cover. A multivariate factor analysis was used to identify the common axes (or dimensions) of pattern and structure which were measured by a reduced set of 26 metrics. The first six factors explained about 87% of the variation in the 26 landscape metrics. These...

Transient Dynamic Response and Failure of Composite Structure Under Cyclic Loading with Fluid Structure Interaction

DTIC Science & Technology

2014-09-01

TERMS fluid structure interaction, composite structures shipbuilding, fatigue loading 15. NUMBER OF PAGES 85 16. PRICE CODE 17. SECURITY...under the three point bending test. All the composites exhibit an initial nonlinear and inelastic deformation trend and end with a catastrophic abrupt

What makes an effective Chagas disease vector? Factors underlying Trypanosoma cruzi-triatomine interactions.

PubMed

de Fuentes-Vicente, José A; Gutiérrez-Cabrera, Ana E; Flores-Villegas, A Laura; Lowenberger, Carl; Benelli, Giovanni; Salazar-Schettino, Paz M; Córdoba-Aguilar, Alex

2018-07-01

The Chagas disease is caused by the parasite Trypanosoma cruzi, which infect blood-feeding triatomine bugs to finally reach mammal hosts. Chagas disease is endemic in Latin America, and is ranked among the 13 neglected tropical diseases worldwide. Currently, an estimate of 7 million people is infected by T. cruzi, leading to about 22 000 deaths per year throughout the Americas. As occurs with other vectors, a major question towards control programs is what makes a susceptible bug. In this review, we focus on findings linked to insect gut structure and microbiota, immunity, genetics, blood sources, abiotic factors (with special reference to ambient temperature and altitude) to understand the interactions occurring between T. cruzi and triatomine bugs, under a co-evolutionary scenario. These factors lead to varying fitness benefits and costs for bugs, explaining why infection in the insect takes place and how it varies in time and space. Our analysis highlights that major factors are gut components and microbiota, blood sources and temperature. Although their close interaction has never been clarified, knowledge reviewed here may help to boost the success of triatomine control programs, reducing the use of insecticides. Copyright © 2018 Elsevier B.V. All rights reserved.

Stress Intensity Factors for Cracked Metallic Structures Under Rapid Thermal Loading

DTIC Science & Technology

1987-10-01

if applicable ) Flight Dynamics Laboratory (AFWAL/FIBFC) APTECH Engineering Services Air Force Wright Aeronautical Laboratories 6c. ADDRESS (City...SPONSORING Bb OFFICE SYMBOL 9 PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION (If applicable ) DOD SBIR Program Office F33615-86-C-3217 8c...flawed components requires the application of fracture mechanics wherein crack tip -tress intensity factors are used to provide a quantitative means

Empirical Analysis of Farm Credit Risk under the Structure Model

ERIC Educational Resources Information Center

Yan, Yan

2009-01-01

The study measures farm credit risk by using farm records collected by Farm Business Farm Management (FBFM) during the period 1995-2004. The study addresses the following questions: (1) whether farm's financial position is fully described by the structure model, (2) what are the determinants of farm capital structure under the structure model, (3)…

New Possible Structure of Silicide Mg2Si under Pressure

NASA Astrophysics Data System (ADS)

Luniakov, Yu. V.

2018-05-01

As a result of an evolutionary search based on the density functional theory, a new low-symmetry structure of silicide Mg2Si under pressure was discovered. This structure can exist along with the known structures of the symmetry Pnma and P63/mmc and is stable at a pressure of about 20 GPa. The lattice parameters of the discovered structure are in better agreement with the experimental values than the lattice parameters of the known structures.

Evaluating the Spatio-Temporal Factors that Structure Network Parameters of Plant-Herbivore Interactions

PubMed Central

López-Carretero, Antonio; Díaz-Castelazo, Cecilia; Boege, Karina; Rico-Gray, Víctor

2014-01-01

Despite the dynamic nature of ecological interactions, most studies on species networks offer static representations of their structure, constraining our understanding of the ecological mechanisms involved in their spatio-temporal stability. This is the first study to evaluate plant-herbivore interaction networks on a small spatio-temporal scale. Specifically, we simultaneously assessed the effect of host plant availability, habitat complexity and seasonality on the structure of plant-herbivore networks in a coastal tropical ecosystem. Our results revealed that changes in the host plant community resulting from seasonality and habitat structure are reflected not only in the herbivore community, but also in the emergent properties (network parameters) of the plant-herbivore interaction network such as connectance, selectiveness and modularity. Habitat conditions and periods that are most stressful favored the presence of less selective and susceptible herbivore species, resulting in increased connectance within networks. In contrast, the high degree of selectivennes (i.e. interaction specialization) and modularity of the networks under less stressful conditions was promoted by the diversification in resource use by herbivores. By analyzing networks at a small spatio-temporal scale we identified the ecological factors structuring this network such as habitat complexity and seasonality. Our research offers new evidence on the role of abiotic and biotic factors in the variation of the properties of species interaction networks. PMID:25340790

Factor structure and individual patterns of DSM-IV conduct disorder criteria in adolescent psychiatric inpatients.

PubMed

Janson, Harald; Kjelsberg, Ellen

2006-01-01

We investigated the factor structure of the DSM-IV conduct disorder (CD) diagnostic criteria and typical individual patterns of CD subscales in an adolescent inpatient population using detailed hospital records of a Norwegian nationwide sample of 1087 adolescent psychiatric inpatients scored for the 15 DSM-IV CD criteria. Varimax rotated principal components and full-information factor analyses of 12 CD criteria were carried out separately for boys and girls employing two methods. Standardized values on three subscales of CD criteria were subjected to Ward's method of hierarchical cluster analyses followed by k-means relocation employing a double cross-replication design. Similar factor structures emerged regardless of factoring method and gender. With the exception of Criteria 8 ("Fire setting") and 14 ("Run away from home") the factor loadings for both genders were in accordance with Loeber's tripartite model, with Aggression, Delinquency, and Rule Breaking factors largely corresponding to Loeber's overt, covert and authority conflict pathways. A five-cluster solution proved highly replicable and interpretable. One cluster gathered adolescents without CD, and the remaining four described groups with different conceptually meaningful constellations of CD criteria, which were not equally prevalent in each gender. Delinquency appeared in all symptomatic clusters. The cluster analytic results highlighted typical forms of expressions of conduct problems, and the fact that these forms may not be equally prevalent in girls and boys even while the underlying structure of conduct problems may be similar across genders. Future research should address the prediction of specific outcomes from CD criteria subscales or constellations.

Evidence Regarding the Internal Structure: Confirmatory Factor Analysis

ERIC Educational Resources Information Center

Lewis, Todd F.

2017-01-01

American Educational Research Association (AERA) standards stipulate that researchers show evidence of the internal structure of instruments. Confirmatory factor analysis (CFA) is one structural equation modeling procedure designed to assess construct validity of assessments that has broad applicability for counselors interested in instrument…

Factors influencing protein tyrosine nitration--structure-based predictive models.

PubMed

Bayden, Alexander S; Yakovlev, Vasily A; Graves, Paul R; Mikkelsen, Ross B; Kellogg, Glen E

2011-03-15

Models for exploring tyrosine nitration in proteins have been created based on 3D structural features of 20 proteins for which high-resolution X-ray crystallographic or NMR data are available and for which nitration of 35 total tyrosines has been experimentally proven under oxidative stress. Factors suggested in previous work to enhance nitration were examined with quantitative structural descriptors. The role of neighboring acidic and basic residues is complex: for the majority of tyrosines that are nitrated the distance to the heteroatom of the closest charged side chain corresponds to the distance needed for suspected nitrating species to form hydrogen bond bridges between the tyrosine and that charged amino acid. This suggests that such bridges play a very important role in tyrosine nitration. Nitration is generally hindered for tyrosines that are buried and for those tyrosines for which there is insufficient space for the nitro group. For in vitro nitration, closed environments with nearby heteroatoms or unsaturated centers that can stabilize radicals are somewhat favored. Four quantitative structure-based models, depending on the conditions of nitration, have been developed for predicting site-specific tyrosine nitration. The best model, relevant for both in vitro and in vivo cases, predicts 30 of 35 tyrosine nitrations (positive predictive value) and has a sensitivity of 60/71 (11 false positives). Copyright © 2010 Elsevier Inc. All rights reserved.

Structural phase transitions in yttrium under ultrahigh pressures

NASA Astrophysics Data System (ADS)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Vohra, Yogesh K.

2012-09-01

X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.

Structural phase transitions in yttrium under ultrahigh pressures.

PubMed

Samudrala, Gopi K; Tsoi, Georgiy M; Vohra, Yogesh K

2012-09-12

X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.

The Factor Structure of the English Language Development Assessment: A Confirmatory Factor Analysis

ERIC Educational Resources Information Center

Kuriakose, Anju

2011-01-01

This study investigated the internal factor structure of the English language development Assessment (ELDA) using confirmatory factor analysis. ELDA is an English language proficiency test developed by a consortium of multiple states and is used to identify and reclassify English language learners in kindergarten to grade 12. Scores on item…

Factor structure of the Minnesota Satisfaction Questionnaire short form for restaurant employees.

PubMed

Hancer, Mura; George, R Thomas

2004-02-01

The factor structure of the Minnesota Satisfaction Questionnaire short form for nonsupervisory restaurant employees was explored in questions among 2000 employees of three full-service restaurant chains operating in midwestern United States. A total of 2000 surveys were distributed to hourly employees of the three chains. From the mailing, 924 surveys were returned and found useable, a 46.2% response rate. Principal factors analysis identified a four-factor structure for the employees, in contrast to the original two-factor structure, but as in other studies the structure was multifactorial.

Psychometric Structure of a Comprehensive Objective Structured Clinical Examination: A Factor Analytic Approach

ERIC Educational Resources Information Center

Volkan, Kevin; Simon, Steven R.; Baker, Harley; Todres, I. David

2004-01-01

Problem Statement and Background: While the psychometric properties of Objective Structured Clinical Examinations (OSCEs) have been studied, their latent structures have not been well characterized. This study examines a factor analytic model of a comprehensive OSCE and addresses implications for measurement of clinical performance. Methods: An…

Selecting the "Best" Factor Structure and Moving Measurement Validation Forward: An Illustration.

PubMed

Schmitt, Thomas A; Sass, Daniel A; Chappelle, Wayne; Thompson, William

2018-04-09

Despite the broad literature base on factor analysis best practices, research seeking to evaluate a measure's psychometric properties frequently fails to consider or follow these recommendations. This leads to incorrect factor structures, numerous and often overly complex competing factor models and, perhaps most harmful, biased model results. Our goal is to demonstrate a practical and actionable process for factor analysis through (a) an overview of six statistical and psychometric issues and approaches to be aware of, investigate, and report when engaging in factor structure validation, along with a flowchart for recommended procedures to understand latent factor structures; (b) demonstrating these issues to provide a summary of the updated Posttraumatic Stress Disorder Checklist (PCL-5) factor models and a rationale for validation; and (c) conducting a comprehensive statistical and psychometric validation of the PCL-5 factor structure to demonstrate all the issues we described earlier. Considering previous research, the PCL-5 was evaluated using a sample of 1,403 U.S. Air Force remotely piloted aircraft operators with high levels of battlefield exposure. Previously proposed PCL-5 factor structures were not supported by the data, but instead a bifactor model is arguably more statistically appropriate.

Teacher Observation of Classroom Adaptation--Checklist: Development and Factor Structure

ERIC Educational Resources Information Center

Koth, Christine W.; Bradshaw, Catherine P.; Leaf, Philip J.

2009-01-01

Two studies examined the validity and factor structure of the Teacher Observation of Classroom Adaptation-Checklist, an instrument used to evaluate school-based programs. The checklist is a cost-effective alternative to the original interview format, and the factor structure is consistent across gender, race, age, and time of administration.…

The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions

PubMed Central

Kang, K-T.; Koh, Y-G.; Jung, M.; Nam, J-H.; Son, J.; Lee, Y.H.

2017-01-01

Objectives The aim of the current study was to analyse the effects of posterior cruciate ligament (PCL) deficiency on forces of the posterolateral corner structure and on tibiofemoral (TF) and patellofemoral (PF) contact force under dynamic-loading conditions. Methods A subject-specific knee model was validated using a passive flexion experiment, electromyography data, muscle activation, and previous experimental studies. The simulation was performed on the musculoskeletal models with and without PCL deficiency using a novel force-dependent kinematics method under gait- and squat-loading conditions, followed by probabilistic analysis for material uncertain to be considered. Results Comparison of predicted passive flexion, posterior drawer kinematics and muscle activation with experimental measurements showed good agreement. Forces of the posterolateral corner structure, and TF and PF contact forces increased with PCL deficiency under gait- and squat-loading conditions. The rate of increase in PF contact force was the greatest during the squat-loading condition. The TF contact forces increased on both medial and lateral compartments during gait-loading conditions. However, during the squat-loading condition, the medial TF contact force tended to increase, while the lateral TF contact forces decreased. The posterolateral corner structure, which showed the greatest increase in force with deficiency of PCL under both gait- and squat-loading conditions, was the popliteus tendon (PT). Conclusion PCL deficiency is a factor affecting the variability of force on the PT in dynamic-loading conditions, and it could lead to degeneration of the PF joint. Cite this article: K-T. Kang, Y-G. Koh, M. Jung, J-H. Nam, J. Son, Y.H. Lee, S-J. Kim, S-H. Kim. The effects of posterior cruciate ligament deficiency on posterolateral corner structures under gait- and squat-loading conditions: A computational knee model. Bone Joint Res 2017;6:31–42. DOI: 10.1302/2046-3758.61.BJR-2016-0184.R1

Placental growth factor expression is reversed by antivascular endothelial growth factor therapy under hypoxic conditions.

PubMed

Zhou, Ai-Yi; Bai, Yu-Jing; Zhao, Min; Yu, Wen-Zhen; Huang, Lv-Zhen; Li, Xiao-Xin

2014-08-01

Clinical trials have revealed that the antivascular endothelial growth factor (VEGF) therapies are effective in retinopathy of prematurity (ROP). But the low level of VEGF was necessary as a survival signal in healthy conditions, and endogenous placental growth factor (PIGF) is redundant for development. The purpose of this study was to elucidate the PIGF expression under hypoxia as well as the influence of anti-VEGF therapy on PIGF. CoCl2-induced hypoxic human umbilical vein endothelial cells (HUVECs) were used for an in vitro study, and oxygen-induced retinopathy (OIR) mice models were used for an in vivo study. The expression patterns of PIGF under hypoxic conditions and the influence of anti-VEGF therapy on PIGF were evaluated by quantitative reverse transcription-polymerase chain reaction (RTPCR). The retinal avascular areas and neovascularization (NV) areas of anti-VEGF, anti-PIGF and combination treatments were calculated. Retina PIGF concentration was evaluated by ELISA after treatment. The vasoactive effects of exogenous PIGF on HUVECs were investigated by proliferation and migration studies. PIGF mRNA expression was reduced by hypoxia in OIR mice, in HUVECs under hypoxia and anti-VEGF treatment. However, PIGF expression was reversed by anti-VEGF therapy in the OIR model and in HUVECs under hypoxia. Exogenous PIGF significantly inhibited HUVECs proliferation and migration under normal conditions, but it stimulated cell proliferation and migration under hypoxia. Anti-PIGF treatment was effective for neovascular tufts in OIR mice (P<0.05). The finding that PIGF expression is iatrogenically up-regulated by anti-VEGF therapy provides a consideration to combine it with anti-PIGF therapy.

Ion-ion dynamic structure factor of warm dense mixtures

DOE PAGES

Gill, N. M.; Heinonen, R. A.; Starrett, C. E.; ...

2015-06-25

In this study, the ion-ion dynamic structure factor of warm dense matter is determined using the recently developed pseudoatom molecular dynamics method [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. The method uses density functional theory to determine ion-ion pair interaction potentials that have no free parameters. These potentials are used in classical molecular dynamics simulations. This constitutes a computationally efficient and realistic model of dense plasmas. Comparison with recently published simulations of the ion-ion dynamic structure factor and sound speed of warm dense aluminum finds good to reasonable agreement. Using this method, we make predictions of the ion-ionmore » dynamical structure factor and sound speed of a warm dense mixture—equimolar carbon-hydrogen. This material is commonly used as an ablator in inertial confinement fusion capsules, and our results are amenable to direct experimental measurement.« less

Factor Structure of Autistic Traits in Children with ADHD

ERIC Educational Resources Information Center

Martin, Joanna; Hamshere, Marian L.; O'Donovan, Michael C.; Rutter, Michael; Thapar, Anita

2014-01-01

Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) often co-occur. Factor analyses of ASD traits in children with and without ASD indicate the presence of social and restrictive-repetitive behaviour (RRB) factors. This study used exploratory factor analyses to determine the structure of ASD traits (assessed using…

Turbulent Structure Under Short Fetch Wind Waves

DTIC Science & Technology

2015-12-01

1970) developed the LFT utilizing the concurrent measurement of sea surface elevation (η) and the near surface velocities to isolate the wave...Layers and Air-Sea Transfer program by making very high spatial resolution profile measurements of the 3-D velocity field into the crest-trough...distribution is unlimited TURBULENT STRUCTURE UNDER SHORT FETCH WIND WAVES Michael J. Papa Lieutenant Commander, United States Navy B.S., United States Naval

Reliability, Validity, and Factor Structure of the Imaginative Capability Scale

ERIC Educational Resources Information Center

Liang, Chaoyun; Chia, Tsorng-Lin

2014-01-01

Three studies were combined to test the reliability, validity, and factor structure of the imaginative capability scale (ICS). The ICS was a new self-report measure, which was developed to be empirically valid and easy to administer. Study 1 consisted in an exploratory factor analysis to determine the most appropriate structure of the ICS in a…

Impacts of Seed Dispersal on Future Vegetation Structure under Changing Climates

NASA Astrophysics Data System (ADS)

Lee, E.; Schlosser, C. A.; Gao, X.; Prinn, R. G.

2011-12-01

As the impacts between land cover change, future climates and ecosystems are expected to be substantial, there are growing needs for improving the capability of simulating the global vegetation structure and landscape as realistically as possible. Current DGVMs assume ubiquitous availability of seeds and do not consider any seed dispersal mechanisms in plant migration process, which may influence the assessment of impacts to the ecosystem that rely on the vegetation structure changes (i.e., change in albedo, runoff, and terrestrial carbon sequestration capacity). This study incorporates time-varying wind-driven seed dispersal (i.e., the SEED configuration) as a dynamic constraint to the migration process of natural vegetation in the Community Land Model (CLM)-DGVM. The SEED configuration is validated using a satellite-derived tree cover dataset. Then the configuration is applied to project future vegetation structures and their implications for carbon fluxes, albedo, and hydrology under two climate mitigation scenarios (No-policy vs. 450ppm CO2 stabilization) for the 21st century. Our results show that regional changes of vegetation structure under changing climates are expected to be significant. For example, Alaska and Siberia are expected to experience substantial shifts of forestry structure, characterized by expansion of needle-leaf boreal forest and shrinkage of C3 grass Arctic. A suggested vulnerability assessment shows that vegetation structures in Alaska, Greenland, Central America, southern South America, East Africa and East Asia are susceptible to changing climates, regardless of the two climate mitigation scenarios. Regions such as Greenland, Tibet, South Asia and Northern Australia, however, may substantially alleviate their risks of rapid change in vegetation structure, given a robust greenhouse gas stabilization target. Proliferation of boreal forests in the high latitudes is expected to amplify the warming trend (i.e., a positive feedback to

Assessing vulnerability to drought: identifying underlying factors across Europe

NASA Astrophysics Data System (ADS)

Urquijo, Julia; Gonzalez Tánago, Itziar; Ballesteros, Mario; De Stefano, Lucia

2015-04-01

Drought is considered one of the most severe and damaging natural hazards in terms of people and sectors affected and associated losses. Drought is a normal and recurrent climatic phenomenon that occurs worldwide, although its spatial and temporal characteristics vary significantly among climates. In the case of Europe, in the last thirty years, the region has suffered several drought events that have caused estimated economic damages over a €100 billion and have affected almost 20% of its territory and population. In recent years, there has been a growing awareness among experts and authorities of the need to shift from a reactive crisis approach to a drought risk management approach, as well as of the importance of designing and implementing policies, strategies and plans at country and river basin levels to deal with drought. The identification of whom and what is vulnerable to drought is a central aspect of drought risk mitigation and planning and several authors agree that societal vulnerability often determines drought risk more than the actual precipitation shortfalls. The final aim of a drought vulnerability assessment is to identify the underlying sources of drought impact, in order to develop policy options that help to enhance coping capacity and therefore to prevent drought impact. This study identifies and maps factors underlying vulnerability to drought across Europe. The identification of factors influencing vulnerability starts from the analysis of past drought impacts in four European socioeconomic sectors. This analysis, along with an extensive literature review, led to the selection of vulnerability factors that are both relevant and adequate for the European context. Adopting the IPCC model, vulnerability factors were grouped to describe exposure, sensitivity and adaptive capacity. The aggregation of these components has resulted in the mapping of vulnerability to drought across Europe at NUTS02 level. Final results have been compared with

Honorary Authorship Practices in Environmental Science Teams: Structural and Cultural Factors and Solutions.

PubMed

Elliott, Kevin C; Settles, Isis H; Montgomery, Georgina M; Brassel, Sheila T; Cheruvelil, Kendra Spence; Soranno, Patricia A

2017-01-01

Overinclusive authorship practices such as honorary or guest authorship have been widely reported, and they appear to be exacerbated by the rise of large interdisciplinary collaborations that make authorship decisions particularly complex. Although many studies have reported on the frequency of honorary authorship and potential solutions to it, few have probed how the underlying dynamics of large interdisciplinary teams contribute to the problem. This article reports on a qualitative study of the authorship standards and practices of six National Science Foundation-funded interdisciplinary environmental science teams. Using interviews of the lead principal investigator and an early-career member on each team, our study explores the nature of honorary authorship practices as well as some of the motivating factors that may contribute to these practices. These factors include both structural elements (policies and procedures) and cultural elements (values and norms) that cross organizational boundaries. Therefore, we provide recommendations that address the intersection of these factors and that can be applied at multiple organizational levels.

Factor Structure of the Student-Teacher Relationship Scale for Norwegian School-Age Children Explored with Confirmatory Factor Analysis

ERIC Educational Resources Information Center

Drugli, May Britt; Hjemdal, Odin

2013-01-01

The validity of the Student-Teacher Relationship Scale (STRS) was examined in a national sample of 863 Norwegian schoolchildren in grades 1-7 (aged 6-13). The original factor structure of the STRS was tested by confirmatory factor analysis (CFA). The CFA results did not support the original three-factor structure of the STRS. Subsequent CFA of the…

Factor Scores, Structure and Communality Coefficients: A Primer

ERIC Educational Resources Information Center

Odum, Mary

2011-01-01

(Purpose) The purpose of this paper is to present an easy-to-understand primer on three important concepts of factor analysis: Factor scores, structure coefficients, and communality coefficients. Given that statistical analyses are a part of a global general linear model (GLM), and utilize weights as an integral part of analyses (Thompson, 2006;…

The Cannabis Abuse Screening Test and the DSM-5 in the general population: Optimal thresholds and underlying common structure using multiple factor analysis.

PubMed

Legleye, Stéphane

2018-06-01

The Cannabis Abuse Screening Test (CAST) aims at screening the problematic use of cannabis. It has never been validated against the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 and its relationships with this latter have never been studied. We used a probabilistic telephone survey collected in 2014 (1351 past-year cannabis users aged 15-64) implementing the CAST and a DSM-5 adaptation of the Munich Composite International Diagnostic Interview assessing cannabis use disorders. Data were weighted, and CAST items were considered categorical. Factorial structures were assessed with confirmatory factor analyses; the relationships between the instruments were studied with multiple factor analysis (MFA). One factor for the DSM-5 and two correlated factors for the CAST were the best confirmatory factor analyses solutions. The CAST thresholds for screening moderate/severe and severe cannabis use disorders were 5 (sensitivity = 78.2% and specificity = 79.6%) and 8 (sensitivity = 86.0% and specificity = 86.7%), respectively. The MFA identified two orthogonal dimensions: The first was equally shared by both instruments; the second was the second CAST dimension (extreme frequencies of use before midday and alone, memory problems, and reproaches from friends/family). The CAST structure and screening properties were confirmed. The MFA explains its screening performances by its first dimension and identified the problematic patterns (the second dimension) that are not captured by the DSM-5. Copyright © 2017 John Wiley & Sons, Ltd.

Confirmatory factor analysis reveals a latent cognitive structure common to bipolar disorder, schizophrenia, and normal controls.

PubMed

Schretlen, David J; Peña, Javier; Aretouli, Eleni; Orue, Izaskun; Cascella, Nicola G; Pearlson, Godfrey D; Ojeda, Natalia

2013-06-01

We sought to determine whether a single hypothesized latent factor structure would characterize cognitive functioning in three distinct groups. We assessed 576 adults (340 community controls, 126 adults with bipolar disorder, and 110 adults with schizophrenia) using 15 measures derived from nine cognitive tests. Confirmatory factor analysis (CFA) was conducted to examine the fit of a hypothesized six-factor model. The hypothesized factors included attention, psychomotor speed, verbal memory, visual memory, ideational fluency, and executive functioning. The six-factor model provided an excellent fit for all three groups [for community controls, root mean square error of approximation (RMSEA) <0.048 and comparative fit index (CFI) = 0.99; for adults with bipolar disorder, RMSEA = 0.071 and CFI = 0.99; and for adults with schizophrenia, RMSEA = 0.06 and CFI = 0.98]. Alternate models that combined fluency with processing speed or verbal and visual memory reduced the goodness of fit. Multi-group CFA results supported factor invariance across the three groups. Confirmatory factor analysis supported a single six-factor structure of cognitive functioning among patients with schizophrenia or bipolar disorder and community controls. While the three groups clearly differ in level of performance, they share a common underlying architecture of information processing abilities. These cognitive factors could provide useful targets for clinical trials of treatments that aim to enhance information processing in persons with neurological and neuropsychiatric disorders. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Lesion Mapping the Four-Factor Structure of Emotional Intelligence

PubMed Central

Operskalski, Joachim T.; Paul, Erick J.; Colom, Roberto; Barbey, Aron K.; Grafman, Jordan

2015-01-01

Emotional intelligence (EI) refers to an individual’s ability to process and respond to emotions, including recognizing the expression of emotions in others, using emotions to enhance thought and decision making, and regulating emotions to drive effective behaviors. Despite their importance for goal-directed social behavior, little is known about the neural mechanisms underlying specific facets of EI. Here, we report findings from a study investigating the neural bases of these specific components for EI in a sample of 130 combat veterans with penetrating traumatic brain injury. We examined the neural mechanisms underlying experiential (perceiving and using emotional information) and strategic (understanding and managing emotions) facets of EI. Factor scores were submitted to voxel-based lesion symptom mapping to elucidate their neural substrates. The results indicate that two facets of EI (perceiving and managing emotions) engage common and distinctive neural systems, with shared dependence on the social knowledge network, and selective engagement of the orbitofrontal and parietal cortex for strategic aspects of emotional information processing. The observed pattern of findings suggests that sub-facets of experiential and strategic EI can be characterized as separable but related processes that depend upon a core network of brain structures within frontal, temporal and parietal cortex. PMID:26858627

The structural and properties of magnesium-phosphorus compounds under pressure.

PubMed

Liu, Yunxian; Wang, Chao; Lv, Pin; Sun, Hairui; Duan, Defang

2018-06-01

Inspired by the emerging of compounds with novel structures and unique properties (i.e., superconductivity and hardness) under high pressure, we systematically explored a binary Mg-P system under pressure combining first-principles calculation with structure prediction. Several stoichiometries (Mg3P, Mg2P, MgP, MgP2, and MgP3) were predicted stable under pressure. Especially, the P-P bonding patterns are different in the P-rich compounds and the Mg-rich compounds: in the former, the P-P bonding patterns form P2, P3, quadrilateral units, P-P***P chains or disordered "graphene-like" sublattice, while in the latter, the P-P bonding patterns eventually isolated P ions. The analysis of integrated crystal orbital Hamilton populations reveals that the P-P interactions are mainly responsible for the structural stability. The P-rich compounds with stoichiometries of MgP, MgP2 and MgP3 exhibit superconductive behaviors, and these phases show Tc in the range of 4.3-20 K. Our study provides useful information for understanding the Mg-P binary compounds at high pressure. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Factor structure of the Brief Negative Symptom Scale.

PubMed

Strauss, Gregory P; Hong, L Elliot; Gold, James M; Buchanan, Robert W; McMahon, Robert P; Keller, William R; Fischer, Bernard A; Catalano, Lauren T; Culbreth, Adam J; Carpenter, William T; Kirkpatrick, Brian

2012-12-01

The current study examined the factor structure of the Brief Negative Symptom Scale (BNSS), a next-generation negative symptom rating instrument developed in response to the NIMH-sponsored Consensus Development Conference on Negative Symptoms. Participants included 146 individuals with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder. Principal axis factoring indicated two distinct factors explaining 68.7% of the variance. Similar to previous findings, the factors reflected motivation and pleasure and emotional expressivity. These findings provide further support for the construct validity of the BNSS, and for the existence of these two negative symptom factors. Copyright © 2012 Elsevier B.V. All rights reserved.

Factor structure of the geriatric care environment scale.

PubMed

Kim, Hongsoo; Capezuti, Elizabeth; Boltz, Marie; Fairchild, Susan; Fulmer, Terry; Mezey, Mathy

2007-01-01

Older adults comprise approximately 60% of all adult, nonobstetric hospital admissions. Nurses Improving Care for Health System Elders (NICHE) is a national program aimed at system improvement to achieve patient-centered care for older adults. The NICHE hospitals use the Geriatric Institutional Assessment Profile (GIAP) to assess their institutional readiness to provide quality care to older adults and to document improvement in geriatric care delivery. To explore the factorial structure of the 28-item Geriatric Care Environment Scale (GCES) of the GIAP, test its validity with a sample of staff registered nurses (RNs), and evaluate its invariance across 4 groups of RNs who worked at 4 different types of hospitals. Staff RNs (N = 9,400) at 71 acute hospitals, who responded to the GIAP from 1999 to 2004, were split randomly into 2 groups for cross-validation. A 3-step data analysis was completed. The a priori factor structure was developed using exploratory factor analysis. The obtained factor model was validated, and its invariance by types of hospitals was examined by confirmatory factor analyses. The GCES is internally consistent (Cronbach's alpha = .93) and accounts for approximately 55% of the total variance. The 4 factors extracted from the exploratory factor analysis are Aging-Sensitive Care Delivery, Resource Availability, Institutional Values Regarding Older Adults and Staff, and Capacity for Collaboration. The 4-factor structured model is validated in a half-randomly selected sample (normed fit index [NFI] = .931, nonnormed fit index [NNFI] = .933, comparative fit index [CFI] = .939, root-mean-square error of approximation [RMSEA] = .058) and does not vary significantly across the 4 groups of RNs who worked at the 4 different types of hospitals (NFI = .969, NNFI = .975, CFI = .976, RMSEA = .027). The GCES is a reliable measure of RN perception of how care provided to older adults reflects age-sensitive principles and the organizational practice environment

Temperament Factor Structure in Fragile X Syndrome: The Children's Behavior Questionnaire

PubMed Central

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

2014-01-01

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

Oriented matroids—combinatorial structures underlying loop quantum gravity

NASA Astrophysics Data System (ADS)

Brunnemann, Johannes; Rideout, David

2010-10-01

We analyze combinatorial structures which play a central role in determining spectral properties of the volume operator (Ashtekar A and Lewandowski J 1998 Adv. Theor. Math. Phys. 1 388) in loop quantum gravity (LQG). These structures encode geometrical information of the embedding of arbitrary valence vertices of a graph in three-dimensional Riemannian space and can be represented by sign strings containing relative orientations of embedded edges. We demonstrate that these signature factors are a special representation of the general mathematical concept of an oriented matroid (Ziegler G M 1998 Electron. J. Comb.; Björner A et al 1999 Oriented Matroids (Cambridge: Cambridge University Press)). Moreover, we show that oriented matroids can also be used to describe the topology (connectedness) of directed graphs. Hence, the mathematical methods developed for oriented matroids can be applied to the difficult combinatorics of embedded graphs underlying the construction of LQG. As a first application we revisit the analysis of Brunnemann and Rideout (2008 Class. Quantum Grav. 25 065001 and 065002), and find that enumeration of all possible sign configurations used there is equivalent to enumerating all realizable oriented matroids of rank 3 (Ziegler G M 1998 Electron. J. Comb.; Björner A et al 1999 Oriented Matroids (Cambridge: Cambridge University Press)), and thus can be greatly simplified. We find that for 7-valent vertices having no coplanar triples of edge tangents, the smallest non-zero eigenvalue of the volume spectrum does not grow as one increases the maximum spin jmax at the vertex, for any orientation of the edge tangents. This indicates that, in contrast to the area operator, considering large jmax does not necessarily imply large volume eigenvalues. In addition we give an outlook to possible starting points for rewriting the combinatorics of LQG in terms of oriented matroids.

Factors influencing protein tyrosine nitration – structure-based predictive models

PubMed Central

Bayden, Alexander S.; Yakovlev, Vasily A.; Graves, Paul R.; Mikkelsen, Ross B.; Kellogg, Glen E.

2010-01-01

Models for exploring tyrosine nitration in proteins have been created based on 3D structural features of 20 proteins for which high resolution X-ray crystallographic or NMR data are available and for which nitration of 35 total tyrosines has been experimentally proven under oxidative stress. Factors suggested in previous work to enhance nitration were examined with quantitative structural descriptors. The role of neighboring acidic and basic residues is complex: for the majority of tyrosines that are nitrated the distance to the heteroatom of the closest charged sidechain corresponds to the distance needed for suspected nitrating species to form hydrogen bond bridges between the tyrosine and that charged amino acid. This suggests that such bridges play a very important role in tyrosine nitration. Nitration is generally hindered for tyrosines that are buried and for those tyrosines where there is insufficient space for the nitro group. For in vitro nitration, closed environments with nearby heteroatoms or unsaturated centers that can stabilize radicals are somewhat favored. Four quantitative structure-based models, depending on the conditions of nitration, have been developed for predicting site-specific tyrosine nitration. The best model, relevant for both in vitro and in vivo cases predicts 30 of 35 tyrosine nitrations (positive predictive value) and has a sensitivity of 60/71 (11 false positives). PMID:21172423

Reliability analysis of structures under periodic proof tests in service

NASA Technical Reports Server (NTRS)

Yang, J.-N.

1976-01-01

A reliability analysis of structures subjected to random service loads and periodic proof tests treats gust loads and maneuver loads as random processes. Crack initiation, crack propagation, and strength degradation are treated as the fatigue process. The time to fatigue crack initiation and ultimate strength are random variables. Residual strength decreases during crack propagation, so that failure rate increases with time. When a structure fails under periodic proof testing, a new structure is built and proof-tested. The probability of structural failure in service is derived from treatment of all the random variables, strength degradations, service loads, proof tests, and the renewal of failed structures. Some numerical examples are worked out.

Underlying pathology and associated factors of hemiplegic shoulder pain.

PubMed

Kalichman, Leonid; Ratmansky, Motti

2011-09-01

The prevalence of hemiplegic shoulder pain is approximately 22%-23% in the general population of stroke survivors and approximately 54%-55% among stroke patients in rehabilitation settings. Hemiplegic shoulder pain causes a reduced quality-of-life, poor functional recovery, depression, disturbed sleep, and prolonged hospitalization. Herein, we attempted to understand, based on a literature review and experts' opinion, the pathologic processes underlying hemiplegic shoulder pain and the major associated factors contributing to its development. The systematization of underlying pathologies was proposed, which might eventually enable a more constructive clinical approach in evaluating and treating patients with hemiplegic shoulder pain.

Measuring the dynamic structure factor of a quantum gas undergoing a structural phase transition

PubMed Central

Landig, Renate; Brennecke, Ferdinand; Mottl, Rafael; Donner, Tobias; Esslinger, Tilman

2015-01-01

The dynamic structure factor is a central quantity describing the physics of quantum many-body systems, capturing structure and collective excitations of a material. In condensed matter, it can be measured via inelastic neutron scattering, which is an energy-resolving probe for the density fluctuations. In ultracold atoms, a similar approach could so far not be applied because of the diluteness of the system. Here we report on a direct, real-time and nondestructive measurement of the dynamic structure factor of a quantum gas exhibiting cavity-mediated long-range interactions. The technique relies on inelastic scattering of photons, stimulated by the enhanced vacuum field inside a high finesse optical cavity. We extract the density fluctuations, their energy and lifetime while the system undergoes a structural phase transition. We observe an occupation of the relevant quasi-particle mode on the level of a few excitations, and provide a theoretical description of this dissipative quantum many-body system. PMID:25944151

Structural composite panel performance under long-term load

Treesearch

Theodore L. Laufenberg

1988-01-01

Information on the performance of wood-based structural composite panels under long-term load is currently needed to permit their use in engineered assemblies and systems. A broad assessment of the time-dependent properties of panels is critical for creating databases and models of the creep-rupture phenomenon that lead to reliability-based design procedures. This...

Brief Symptom Inventory Factor Structure in Antisocial Adolescents: Implications for Juvenile Justice

ERIC Educational Resources Information Center

Whitt, Ahmed; Howard, Matthew O.

2012-01-01

Objectives: The Brief Symptom Inventory (BSI) is widely used in juvenile justice settings; however, little is known regarding its factor structure in antisocial youth. The authors evaluated the BSI factor structure in a state residential treatment population. Methods: 707 adolescents completed the BSI. Exploratory and confirmatory factor analyses…

Structure and dynamics of zymogen human blood coagulation factor X.

PubMed

Venkateswarlu, Divi; Perera, Lalith; Darden, Tom; Pedersen, Lee G

2002-03-01

The solution structure and dynamics of the human coagulation factor X (FX) have been investigated to understand the key structural elements in the zymogenic form that participates in the activation process. The model was constructed based on the 2.3-A-resolution x-ray crystallographic structure of active-site inhibited human FXa (PDB:1XKA). The missing gamma-carboxyglutamic acid (GLA) and part of epidermal growth factor 1 (EGF1) domains of the light chain were modeled based on the template of GLA-EGF1 domains of the tissue factor (TF)-bound FVIIa structure (PDB:1DAN). The activation peptide and other missing segments of FX were introduced using homology modeling. The full calcium-bound model of FX was subjected to 6.2 ns of molecular dynamics simulation in aqueous medium using the AMBER6.0 package. We observed significant reorientation of the serine-protease (SP) domain upon activation leading to a compact multi-domain structure. The solution structure of zymogen appears to be in a well-extended conformation with the distance between the calcium ions in the GLA domain and the catalytic residues estimated to be approximately 95 A in contrast to approximately 83 A in the activated form. The latter is in close agreement with fluorescence studies on FXa. The S1-specificity residues near the catalytic triad show significant differences between the zymogen and activated structures.

Underwound DNA under Tension: Structure, Elasticity, and Sequence-Dependent Behaviors

NASA Astrophysics Data System (ADS)

Sheinin, Maxim Y.; Forth, Scott; Marko, John F.; Wang, Michelle D.

2011-09-01

DNA melting under torsion plays an important role in a wide variety of cellular processes. In the present Letter, we have investigated DNA melting at the single-molecule level using an angular optical trap. By directly measuring force, extension, torque, and angle of DNA, we determined the structural and elastic parameters of torsionally melted DNA. Our data reveal that under moderate forces, the melted DNA assumes a left-handed structure as opposed to an open bubble conformation and is highly torsionally compliant. We have also discovered that at low forces melted DNA properties are highly dependent on DNA sequence. These results provide a more comprehensive picture of the global DNA force-torque phase diagram.

Latent factor structure of a behavioral economic cigarette demand curve in adolescent smokers.

PubMed

Bidwell, L Cinnamon; MacKillop, James; Murphy, James G; Tidey, Jennifer W; Colby, Suzanne M

2012-11-01

Behavioral economic demand curves, or quantitative representations of drug consumption across a range of prices, have been used to assess motivation for a variety of drugs. Such curves generate multiple measures of drug demand that are associated with cigarette consumption and nicotine dependence. However, little is known about the relationships among these facets of demand. The aim of the study was to quantify these relationships in adolescent smokers by using exploratory factor analysis to examine the underlying structure of the facets of nicotine incentive value generated from a demand curve measure. Participants were 138 adolescent smokers who completed a hypothetical cigarette purchase task, which assessed estimated cigarette consumption at escalating levels of price/cigarette. Demand curves and five facets of demand were generated from the measure: Elasticity (i.e., 1/α or proportionate price sensitivity); Intensity (i.e., consumption at zero price); O(max) (i.e., maximum financial expenditure on cigarettes); P(max) (i.e., price at which expenditure is maximized); and Breakpoint (i.e., the price that suppresses consumption to zero). Principal components analysis was used to examine the latent structure among the variables. The results revealed a two-factor solution, which were interpreted as "Persistence," reflecting insensitivity to escalating price, and "Amplitude," reflecting the absolute levels of consumption and price. These findings suggest a two factor structure of nicotine incentive value as measured via a demand curve. If supported, these findings have implications for understanding the relationships among individual demand indices in future behavioral economic studies and may further contribute to understanding of the nature of cigarette reinforcement. Copyright © 2012 Elsevier Ltd. All rights reserved.

Latent factor structure of a behavioral economic cigarette demand curve in adolescent smokers

PubMed Central

Bidwell, L. Cinnamon; MacKillop, James; Murphy, James G.; Tidey, Jennifer W.; Colby, Suzanne M.

2012-01-01

Behavioral economic demand curves, or quantitative representations of drug consumption across a range of prices, have been used to assess motivation for a variety of drugs. Such curves generate multiple measures of drug demand that are associated with cigarette consumption and nicotine dependence. However, little is known about the relationships among these facets of demand. The aim of the study was to quantify these relationships in adolescent smokers by using exploratory factor analysis to examine the underlying structure of the facets of nicotine incentive value generated from a demand curve measure. Participants were 138 adolescent smokers who completed a hypothetical cigarette purchase task, which assessed estimated cigarette consumption at escalating levels of price/cigarette. Demand curves and five facets of demand were generated from the measure: Elasticity (i.e., 1/α or proportionate price sensitivity); Intensity (i.e., consumption at zero price); Omax (i.e., maximum financial expenditure on cigarettes); Pmax (i.e., price at which expenditure is maximized); and Breakpoint (i.e., the price that suppresses consumption to zero). Principal components analysis was used to examine the latent structure among the variables. The results revealed a two-factor solution, which were interpreted as “Persistence,” reflecting insensitivity to escalating price, and “Amplitude,” reflecting the absolute levels of consumption and price. These findings suggest a two factor structure of nicotine incentive value as measured via a demand curve. If supported, these findings have implications for understanding the relationships among individual demand indices in future behavioral economic studies and may further contribute to understanding of the nature of cigarette reinforcement. PMID:22727784

Sequence-Dependent Structure/Function Relationships of Catalytic Peptide-Enabled Gold Nanoparticles Generated under Ambient Synthetic Conditions.

PubMed

Bedford, Nicholas M; Hughes, Zak E; Tang, Zhenghua; Li, Yue; Briggs, Beverly D; Ren, Yang; Swihart, Mark T; Petkov, Valeri G; Naik, Rajesh R; Knecht, Marc R; Walsh, Tiffany R

2016-01-20

Peptide-enabled nanoparticle (NP) synthesis routes can create and/or assemble functional nanomaterials under environmentally friendly conditions, with properties dictated by complex interactions at the biotic/abiotic interface. Manipulation of this interface through sequence modification can provide the capability for material properties to be tailored to create enhanced materials for energy, catalysis, and sensing applications. Fully realizing the potential of these materials requires a comprehensive understanding of sequence-dependent structure/function relationships that is presently lacking. In this work, the atomic-scale structures of a series of peptide-capped Au NPs are determined using a combination of atomic pair distribution function analysis of high-energy X-ray diffraction data and advanced molecular dynamics (MD) simulations. The Au NPs produced with different peptide sequences exhibit varying degrees of catalytic activity for the exemplar reaction 4-nitrophenol reduction. The experimentally derived atomic-scale NP configurations reveal sequence-dependent differences in structural order at the NP surface. Replica exchange with solute-tempering MD simulations are then used to predict the morphology of the peptide overlayer on these Au NPs and identify factors determining the structure/catalytic properties relationship. We show that the amount of exposed Au surface, the underlying surface structural disorder, and the interaction strength of the peptide with the Au surface all influence catalytic performance. A simplified computational prediction of catalytic performance is developed that can potentially serve as a screening tool for future studies. Our approach provides a platform for broadening the analysis of catalytic peptide-enabled metallic NP systems, potentially allowing for the development of rational design rules for property enhancement.

Factor Structure of ImPACT® in Adolescent Student Athletes.

PubMed

Gerrard, Paul B; Iverson, Grant L; Atkins, Joseph E; Maxwell, Bruce A; Zafonte, Ross; Schatz, Philip; Berkner, Paul D

2017-02-01

ImPACT ® (Immediate Post-Concussion Assessment and Cognitive Testing) is a computerized neuropsychological screening battery, which is widely used to measure the acute effects of sport-related concussion and to monitor recovery from injury. This study examined the factor structure of ImPACT ® in several samples of high school student athletes. We hypothesized that a 2-factor structure would be present in all samples. A sample of 4,809 adolescent student athletes was included, and subgroups with a history of treatment for headaches or a self-reported history of learning problems or attention-deficit hyperactivity disorder were analyzed separately. Exploratory principal axis factor analyses with Promax rotations were used. As hypothesized, both the combination of Verbal Memory and Visual Memory Composite scores loaded on one (Memory) factor, while Visual Motor Speed and Reaction Time loaded on a different (Speed) factor, in the total sample and in all subgroups. These results provide reasonably compelling evidence, across multiple samples, which ImPACT ® measures 2 distinct factors: memory and speed. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Structure of Plasmodium falciparum ADP-ribosylation factor 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, William J.; Smith, Craig D.; Senkovich, Olga

Vesicular trafficking may play a crucial role in the pathogenesis and survival of the malaria parasite. ADP-ribosylation factors (ARFs) are among the major components of vesicular trafficking pathways in eukaryotes. The crystal structure of ARF1 GTPase from Plasmodium falciparum has been determined in the GDP-bound conformation at 2.5 {angstrom} resolution and is compared with the structures of mammalian ARF1s.

Factor structure and clinical utility of the Beck depression inventory in patients with binge eating disorder and obesity.

PubMed

Udo, Tomoko; McKee, Sherry A; Grilo, Carlos M

2015-01-01

The Beck Depression Inventory (BDI) is often used to assess depression symptoms, but its factor structure and its clinical utility have not been evaluated in patients with binge eating disorder (BED) and obesity. A total of 882 treatment-seeking obese patients with BED were administered structured interviews (Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis I Disorders) and completed self-report questionnaires. Exploratory and confirmatory factor analyses supported a brief 16-item BDI version with a three-factor structure (affective, attitudinal and somatic). Both 21- and 16-item versions showed excellent internal consistency (both α=0.89) and had significant correlation patterns with different aspects of eating disorder psychopathology; three factors showed significant but variable associations with eating disorder psychopathology. Area under the curves (AUC) for both BDI versions were significant in predicting major depressive disorder (MDD; AUC=0.773 [16-item], 73.5% sensitivity/70.2% specificity, AUC=0.769 [21-item], 79.5% sensitivity/64.1% specificity) and mood disorders (AUC=0.763 [16-item], 67.1% sensitivity/71.5% specificity, AUC=0.769 [21-item], 84.2% sensitivity/55.7% specificity). The 21-item BDI (cutoff score ≥16) showed higher negative predictive values (94.0% vs. 93.0% [MDD]; 92.4% vs. 88.3% [mood disorders]) than the brief 16-item BDI (cutoff score ≥13). Both BDI versions demonstrated moderate performance as a screening instrument for MDD/mood disorders in obese patients with BED. Advantages and disadvantages for both versions are discussed. A three-factor structure has potential to inform the conceptualization of depression features. Copyright © 2015 Elsevier Inc. All rights reserved.

Numerical Flexural Strength Analysis of Thermally Stressed Delaminated Composite Structure under Sinusoidal Loading

NASA Astrophysics Data System (ADS)

Hirwani, C. K.; Biswash, S.; Mehar, K.; Panda, S. K.

2018-03-01

In this article, we investigate the thermomechanical deflection characteristics of the debonded composite plate structure using an isoparametric type of higher-order finite element model. The current formulation is derived using higher-order kinematic theory and the displacement variables described as constant along the thickness direction whereas varying nonlinearly for the in-plane directions. The present mid-plane kinematic model mainly obsoletes the use of shear correction factor as in the other lower-order theories. The separation between the adjacent layers is modeled via the sub-laminate technique and the intermittent continuity conditions imposed to avoid the mathematical ill conditions. The governing equation of equilibrium of the damaged plate structure under the combined state of loading are obtained using the variational principle and solved numerically to compute the deflection values. Further, the convergence test has been performed by refining the numbers of elements and validated through comparing the present results with available published values. The usefulness of the proposed formulation has been discussed by solving the different kind of numerical examples including the size, location and position of delamination.

8. Inverted siphon structure carrying ditch flow under Willow Creek, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. Inverted siphon structure carrying ditch flow under Willow Creek, looking southwest - Natomas Ditch System, Blue Ravine Segment, Juncture of Blue Ravine & Green Valley Roads, Folsom, Sacramento County, CA

7. Inverted siphon structure carrying ditch flow under Willow Creek, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Inverted siphon structure carrying ditch flow under Willow Creek, looking east - Natomas Ditch System, Blue Ravine Segment, Juncture of Blue Ravine & Green Valley Roads, Folsom, Sacramento County, CA

Nonlinear system identification of smart structures under high impact loads

NASA Astrophysics Data System (ADS)

Sarp Arsava, Kemal; Kim, Yeesock; El-Korchi, Tahar; Park, Hyo Seon

2013-05-01

The main purpose of this paper is to develop numerical models for the prediction and analysis of the highly nonlinear behavior of integrated structure control systems subjected to high impact loading. A time-delayed adaptive neuro-fuzzy inference system (TANFIS) is proposed for modeling of the complex nonlinear behavior of smart structures equipped with magnetorheological (MR) dampers under high impact forces. Experimental studies are performed to generate sets of input and output data for training and validation of the TANFIS models. The high impact load and current signals are used as the input disturbance and control signals while the displacement and acceleration responses from the structure-MR damper system are used as the output signals. The benchmark adaptive neuro-fuzzy inference system (ANFIS) is used as a baseline. Comparisons of the trained TANFIS models with experimental results demonstrate that the TANFIS modeling framework is an effective way to capture nonlinear behavior of integrated structure-MR damper systems under high impact loading. In addition, the performance of the TANFIS model is much better than that of ANFIS in both the training and the validation processes.

Peplau's Theory of Interpersonal Relations: An Alternate Factor Structure for Patient Experience Data?

PubMed

Hagerty, Thomas A; Samuels, William; Norcini-Pala, Andrea; Gigliotti, Eileen

2017-04-01

A confirmatory factor analysis of data from the responses of 12,436 patients to 16 items on the Consumer Assessment of Healthcare Providers and Systems-Hospital survey was used to test a latent factor structure based on Peplau's middle-range theory of interpersonal relations. A two-factor model based on Peplau's theory fit these data well, whereas a three-factor model also based on Peplau's theory fit them excellently and provided a suitable alternate factor structure for the data. Though neither the two- nor three-factor model fit as well as the original factor structure, these results support using Peplau's theory to demonstrate nursing's extensive contribution to the experiences of hospitalized patients.

Establishing Evidence for Internal Structure Using Exploratory Factor Analysis

ERIC Educational Resources Information Center

Watson, Joshua C.

2017-01-01

Exploratory factor analysis (EFA) is a data reduction technique used to condense data into smaller sets of summary variables by identifying underlying factors potentially accounting for patterns of collinearity among said variables. Using an illustrative example, the 5 general steps of EFA are described with best practices for decision making…

Factor Structure and Psychometric Properties of the Injection Phobia Scale-Anxiety

ERIC Educational Resources Information Center

Olatunji, Bunmi O.; Sawchuk, Craig N.; Moretz, Melanie W.; David, Bieke; Armstrong, Thomas; Ciesielski, Bethany G.

2010-01-01

The present investigation examined the factor structure and psychometric properties of the Injection Phobia Scale-Anxiety (IPS-Anx). Principal components analysis of IPS-Anx items in Study 1 (n = 498) revealed a 2-factor structure consisting of Distal Fear and Contact Fear. However, CFA results in Study 2 (n = 567) suggest that a 1-factor…

The factor structure of the Alcohol Use Disorders Identification Test (AUDIT).

PubMed

Doyle, Suzanne R; Donovan, Dennis M; Kivlahan, Daniel R

2007-05-01

Past research assessing the factor structure of the Alcohol Use Disorders Identification Test (AUDIT) with various exploratory and confirmatory factor analytic techniques has identified one-, two-, and three-factor solutions. Because different factor analytic procedures may result in dissimilar findings, we examined the factor structure of the AUDIT using the same factor analytic technique on two new large clinical samples and on archival data from six samples studied in previous reports. Responses to the AUDIT were obtained from participants who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), criteria for alcohol dependence in two large randomized clinical trials: the COMBINE (Combining Medications and Behavioral Interventions) Study (N = 1,337; 69% men) and Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity; N = 1,711; 76% men). Supplementary analyses involved six correlation matrices of AUDIT data obtained from five previously published articles. Confirmatory factor analyses based on one-, two-, and three-factor models were conducted on the eight correlation matrices to assess the factor structure of the AUDIT. Across samples, analyses supported a correlated, two-factor solution representing alcohol consumption and alcohol-related consequences. The three-factor solution fit the data equally well, but two factors (alcohol dependence and harmful alcohol use) were highly correlated. The one-factor solution did not provide a good fit to the data. These findings support a two-factor solution for the AUDIT (alcohol consumption and alcohol-related consequences). The results contradict the original three-factor design of the AUDIT and the prevalent use of the AUDIT as a one-factor screening instrument with a single cutoff score.

Physical factors underlying the association between lower walking performance and falls in older people: a structural equation model.

PubMed

Shimada, Hiroyuki; Tiedemann, Anne; Lord, Stephen R; Suzukawa, Megumi; Makizako, Hyuma; Kobayashi, Kumiko; Suzuki, Takao

2011-01-01

The purpose of this study was to determine the interrelationships between lower limb muscle performance, balance, gait and falls in older people using structural equation modeling. Study participants were two hundred and thirteen people aged 65 years and older (mean age, 80.0 ± 7.1 years), who used day-care services in Japan. The outcome measures were the history of falls three months retrospectively and physical risk factors for falling, including performance in the chair stand test (CST), one-leg standing test (OLS), tandem walk test, 6m walking time, and the timed up-and-go (TUG) test. Thirty-nine (18.3%) of the 213 participants had fallen at least one or more times during the preceding 3 months. The fall group had significantly slower 6m walking speed and took significantly longer to undertake the TUG test than the non-fall group. In a structural equation model, performance in the CST contributed significantly to gait function, and low gait function was significantly and directly associated with falls in older people. This suggests that task-specific strength exercise as well as general mobility retraining should be important components of exercise programs designed to reduce falls in older people. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Similarity and diversity of translational GTPase factors EF-G, EF4, and BipA: From structure to function.

PubMed

Ero, Rya; Kumar, Veerendra; Chen, Yun; Gao, Yong-Gui

2016-12-01

EF-G, EF4, and BipA are members of the translation factor family of GTPases with a common ribosome binding mode and GTPase activation mechanism. However, topological variations of shared as well as unique domains ensure different roles played by these proteins during translation. Recent X-ray crystallography and cryo-electron microscopy studies have revealed the structural basis for the involvement of EF-G domain IV in securing the movement of tRNAs and mRNA during translocation as well as revealing how the unique C-terminal domains of EF4 and BipA interact with the ribosome and tRNAs contributing to the regulation of translation under certain conditions. EF-G, EF-4, and BipA are intriguing examples of structural variations on a common theme that results in diverse behavior and function. Structural studies of translational GTPase factors have been greatly facilitated by the use of antibiotics, which have revealed their mechanism of action.

Structure and thermoelectric properties of Al-doped ZnO films prepared by thermal oxidization under high magnetic field

NASA Astrophysics Data System (ADS)

Liu, Shiying; Peng, Sunjuan; Ma, Jun; Li, Guojian; Qin, Xuesi; Li, Mengmeng; Wang, Qiang

2017-04-01

This paper studies the effects of high magnetic field (HMF) on the structure, optical and thermoelectric properties of the doped ZnO thin films. The results show that both Al dopant and application of HMF can affect the crystal structure, surface morphology, elemental distribution and so on. The particles of the thin films become small and regular by doping Al. The ZnO films oxidized from the Au/Zn bilayer have needle structure. The ZnO films oxidized from the Au/Zn-Al bilayer transform to spherical from hexagonal due to the application of HMF. The transmittance decreases with doping Al because of the opaque of Al element and decreases with the application of HMF due to the dense structure obtained under HMF. Electrical resistivity (ρ) of the ZnO films without Al decreases with increasing measurement temperature (T) and is about 1.5 × 10-3 Ω·m at 210 °C. However, the ρ of the Al-doped ZnO films is less than 10-5 Ω·m. The Seebeck coefficient (S) of the films oxidized from the Au/Zn-Al films reduces with increasing T. The S values oxidized under 0 T and 12 T conditions are 2.439 μV/K and -3.415 μV/K at 210 °C, respectively. Power factor reaches the maximum value (3.198 × 10-4 W/m·K2) at 210 °C for the film oxidized under 12 T condition. These results indicate that the Al dopant and the application of HMF can be used to control structure and thermoelectric properties of doped ZnO films.

Modelling the factor structure of the Child Depression Inventory in a population of apparently healthy adolescents in Nigeria.

PubMed

Olorunju, Samson Bamidele; Akpa, Onoja Matthew; Afolabi, Rotimi Felix

2018-01-01

Childhood and adolescent depression is common and often persists into adulthood with negative implications for school performances, peer relationship and behavioural functioning. The Child Depression Inventory (CDI) has been used to assess depression among adolescents in many countries including Nigeria but it is uncertain if the theoretical structure of CDI appropriately fits the experiences of adolescents in Nigeria. This study assessed varying theoretical modelling structure of the CDI in a population of apparently healthy adolescents in Benue state, Nigeria. Data was extracted on CDI scale and demographic information from a total of 1, 963 adolescents (aged 10-19 years), who participated in a state wide study assessing adolescent psychosocial functioning. In addition to descriptive statistics and reliability tests, Exploratory Factor Analysis (EFA) and Confirmatory Factor analysis (CFA) were used to model the underlying factor structure and its adequacy. The suggested new model was compared with existing CDI models as well as the CDI's original theoretical model. A model is considered better, if it has minimum Root Mean Square Error of Approximation (RMSEA<0.05), Minimum value of Discrepancy (CMIN/DF<3.0) and Akaike information criteria. All analyses were performed at 95% confidence level, using the version 21 of AMOS and the R software. Participants were 14.7±2.1 years and mostly male (54.3%), from Monogamous homes (67.9%) and lived in urban areas (52.2%). The measure of the overall internal consistency of the 2-factor CDI was α = 0.84. The 2-factor model had the minimum RMSEA (0.044), CMIN/DF (2.87) and least AIC (1037.996) compared to the other five CDI models. The child depression inventory has a 2-factor structure in a non-clinical general population of adolescents in Nigeria. Future use of the CDI in related setting may consider the 2-factor model.

An analysis of the structure of the compound biological effectiveness factor.

PubMed

Ono, Koji

2016-08-01

This report is an analysis of the structure of the compound biological effectiveness (CBE) factor. The value of the CBE factor previously reported was revalued for the central nervous system, skin and lung. To describe the structure, the following terms are introduced: the vascular CBE (v-CBE), intraluminal CBE (il-CBE), extraluminal CBE (el-CBE) and non-vascular CBE (nv-CBE) factors and the geometric biological factor (GBF), i.e. the contributions that are derived from the total dose to the vasculature, each dose to vasculature from the intraluminal side and the extraluminal side, the dose to the non-vascular tissue and the factor to calculate el-CBE from il-CBE, respectively. The el-CBE factor element was also introduced to relate il-CBE to el-CBE factors. A CBE factor of 0.36 for disodium mercaptoundecahydrododecaborate (BSH) for the CNS was independent of the (10)B level in the blood; however, that for p-Boron-L-phenylalanine (BPA) increased with the (10)B level ratio of the normal tissue to the blood (N/B). The CBE factor was expressed as follows: factor = 0.32 + N/B × 1.65. The factor of 0.32 at 0 of N/B was close to the CBE factor for BSH. GBFs had similar values, between BSH and BPA, 1.39 and 1.52, respectively. The structure of the CBE factor for BPA to the lung was also elucidated based on this idea. The factor is described as follows: CBE factor = 0.32 + N/B × 1.80. By this elucidation of the structure of the CBE factor, it is expected that basic and clinical research into boron neutron capture therapy will progress. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Information Structures and Pedagogic Applications.

ERIC Educational Resources Information Center

Chambers, F.

The underlying structure of meaning in a text is to a certain extent belied by the surface structure, or sequential organization, of the text. The underlying information structures (IS) organize information according to cognitive and cultural factors. It may be demonstrated that just three major IS with various subvarieties can describe any text:…

Factor structure and validation of the Attentional Control Scale.

PubMed

Judah, Matt R; Grant, DeMond M; Mills, Adam C; Lechner, William V

2014-04-01

The Attentional Control Scale (ACS; Derryberry & Reed, 2002) has been used to assess executive control over attention in numerous studies, but no published data have examined the factor structure of the English version. The current studies addressed this need and tested the predictive and convergent validity of the ACS subscales. In Study 1, exploratory factor analysis yielded a two-factor model with Focusing and Shifting subscales. In Study 2, confirmatory factor analysis supported this model and suggested superior fit compared to the factor structure of the Icelandic version (Ólafsson et al., 2011). Study 3 examined correlations between the ACS subscales and measures of working memory, anxiety, and cognitive control. Study 4 examined correlations between the subscales and reaction times on a mixed-antisaccade task, revealing positive correlations for antisaccade performance and prosaccade latency with Focusing scores and between switch trial performance and Shifting scores. Additionally, the findings partially supported unique relationships between Focusing and trait anxiety and between Shifting and depression that have been noted in recent research. Although the results generally support the validity of the ACS, additional research using performance-based tasks is needed.

A novel sensitivity-based method for damage detection of structures under unknown periodic excitations

NASA Astrophysics Data System (ADS)

Naseralavi, S. S.; Salajegheh, E.; Fadaee, M. J.; Salajegheh, J.

2014-06-01

This paper presents a technique for damage detection in structures under unknown periodic excitations using the transient displacement response. The method is capable of identifying the damage parameters without finding the input excitations. We first define the concept of displacement space as a linear space in which each point represents displacements of structure under an excitation and initial condition. Roughly speaking, the method is based on the fact that structural displacements under free and forced vibrations are associated with two parallel subspaces in the displacement space. Considering this novel geometrical viewpoint, an equation called kernel parallelization equation (KPE) is derived for damage detection under unknown periodic excitations and a sensitivity-based algorithm for solving KPE is proposed accordingly. The method is evaluated via three case studies under periodic excitations, which confirm the efficiency of the proposed method.

The factor structure of the illness attitude scales in a German population.

PubMed

Weck, Florian; Bleichhardt, Gaby; Hiller, Wolfgang

2009-01-01

The illness attitudes scales (IAS) were developed to identify different dimensions of hypochondrical attitudes, fears, beliefs, and abnormal illness behavior (Kellner 1986). Although there are several studies which focus on the scale structure of the IAS, the factor structure has not yet been made quite clear. Therefore, the aim of this study was to investigate the factor structure of the IAS on a large representative sample. Participants (N = 1,575) comparable with the general German population regarding sex, age, and education level completed the IAS. For the data analyses, a principal components analyses with subsequent oblique rotations was used. The minimum average partial method suggested a three-factor solution. The three factors were named (1) health anxiety, (2) health behavior, and (3) health habits. Internal consistency (Cronbach's alpha) for the three scales were (1) alpha = 0.88, (2) alpha = 0.75, and (3) alpha = 0.56. The results support previous findings, namely that the IAS factor structure appears to be less complex than originally suggested by the author. For a sample of the general German population, a three-factor solution fit best. Further items should be added to improve the internal consistency, especially for the third scale (health habits).

Sequence-Dependent Structure/Function Relationships of Catalytic Peptide-Enabled Gold Nanoparticles Generated under Ambient Synthetic Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bedford, Nicholas M.; Hughes, Zak E.; Tang, Zhenghua

Peptide-enabled nanoparticle (NP) synthesis routes can create and/or assemble functional nanomaterials under environmentally friendly conditions, with properties dictated by complex interactions at the biotic/abiotic interface. Manipulation of this interface through sequence modification can provide the capability for material properties to be tailored to create enhanced materials for energy, catalysis, and sensing applications. Fully realizing the potential of these materials requires a comprehensive understanding of sequence-dependent structure/function relationships that is presently lacking. In this work, the atomic-scale structures of a series of peptide-capped Au NPs are determined using a combination of atomic pair distribution function analysis of high-energy X-ray diffraction datamore » and advanced molecular dynamics (MD) simulations. The Au NPs produced with different peptide sequences exhibit varying degrees of catalytic activity for the exemplar reaction 4-nitrophenol reduction. The experimentally derived atomic-scale NP configurations reveal sequence-dependent differences in structural order at the NP surface. Replica exchange with solute-tempering MD simulations are then used to predict the morphology of the peptide overlayer on these Au NPs and identify factors determining the structure/catalytic properties relationship. We show that the amount of exposed Au surface, the underlying surface structural disorder, and the interaction strength of the peptide with the Au surface all influence catalytic performance. A simplified computational prediction of catalytic performance is developed that can potentially serve as a screening tool for future studies. Our approach provides a platform for broadening the analysis of catalytic peptide-enabled metallic NP systems, potentially allowing for the development of rational design rules for property enhancement.« less

On a fast calculation of structure factors at a subatomic resolution.

PubMed

Afonine, P V; Urzhumtsev, A

2004-01-01

In the last decade, the progress of protein crystallography allowed several protein structures to be solved at a resolution higher than 0.9 A. Such studies provide researchers with important new information reflecting very fine structural details. The signal from these details is very weak with respect to that corresponding to the whole structure. Its analysis requires high-quality data, which previously were available only for crystals of small molecules, and a high accuracy of calculations. The calculation of structure factors using direct formulae, traditional for 'small-molecule' crystallography, allows a relatively simple accuracy control. For macromolecular crystals, diffraction data sets at a subatomic resolution contain hundreds of thousands of reflections, and the number of parameters used to describe the corresponding models may reach the same order. Therefore, the direct way of calculating structure factors becomes very time expensive when applied to large molecules. These problems of high accuracy and computational efficiency require a re-examination of computer tools and algorithms. The calculation of model structure factors through an intermediate generation of an electron density [Sayre (1951). Acta Cryst. 4, 362-367; Ten Eyck (1977). Acta Cryst. A33, 486-492] may be much more computationally efficient, but contains some parameters (grid step, 'effective' atom radii etc.) whose influence on the accuracy of the calculation is not straightforward. At the same time, the choice of parameters within safety margins that largely ensure a sufficient accuracy may result in a significant loss of the CPU time, making it close to the time for the direct-formulae calculations. The impact of the different parameters on the computer efficiency of structure-factor calculation is studied. It is shown that an appropriate choice of these parameters allows the structure factors to be obtained with a high accuracy and in a significantly shorter time than that required

Three-factor structure for Epistemic Belief Inventory: A cross-validation study

PubMed Central

2017-01-01

Research on epistemic beliefs has been hampered by lack of validated models and measurement instruments. The most widely used instrument is the Epistemological Questionnaire, which has been criticized for validity, and it has been proposed a new instrument based in the Epistemological Questionnaire: the Epistemic Belief Inventory. The Spanish-language version of Epistemic Belief Inventory was applied to 1,785 Chilean high school students. Exploratory and confirmatory factor analyses in independent subsamples were performed. A three factor structure emerged and was confirmed. Reliability was comparable to other studies, and the factor structure was invariant among randomized subsamples. The structure that was found does not replicate the one proposed originally, but results are interpreted in light of embedded systemic model of epistemological beliefs. PMID:28278258

Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions

DTIC Science & Technology

2013-01-01

REPORT Friction Stir Weld Failure Mechanisms in Aluminum -Armor Structures Under Ballistic Impact Loading Conditions 14. ABSTRACT 16. SECURITY...Stir Weld Failure Mechanisms in Aluminum -Armor Structures Under Ballistic Impact Loading Conditions M. Grujicic, B. Pandurangan, A. Arakere, C-F. Yen...K.O. Pedersen, Fracture Mechanisms of Aluminum Alloy AA7075-T651 Under Various Loading Conditions , Int. J. Impact Eng., 2010, 37, p 537–551 24. T

Characterizing Thematized Derivative Schema by the Underlying Emergent Structures

ERIC Educational Resources Information Center

Garcia, Mercedes; Llinares, Salvador; Sanchez-Matamoros, Gloria

2011-01-01

This paper reports on different underlying structures of the derivative schema of three undergraduate students that were considered to be at the trans level of development of the derivative schema (action-process-object-schema). The derivative schema is characterized in terms of the students' ability to explicitly transfer the relationship between…

Hardware-Based Non-Optimum Factors for Launch Vehicle Structural Design

NASA Technical Reports Server (NTRS)

Wu, K. Chauncey; Cerro, Jeffrey A.

2010-01-01

During aerospace vehicle conceptual and preliminary design, empirical non-optimum factors are typically applied to predicted structural component weights to account for undefined manufacturing and design details. Non-optimum factors are developed here for 32 aluminum-lithium 2195 orthogrid panels comprising the liquid hydrogen tank barrel of the Space Shuttle External Tank using measured panel weights and manufacturing drawings. Minimum values for skin thickness, axial and circumferential blade stiffener thickness and spacing, and overall panel thickness are used to estimate individual panel weights. Panel non-optimum factors computed using a coarse weights model range from 1.21 to 1.77, and a refined weights model (including weld lands and skin and stiffener transition details) yields non-optimum factors of between 1.02 and 1.54. Acreage panels have an average 1.24 non-optimum factor using the coarse model, and 1.03 with the refined version. The observed consistency of these acreage non-optimum factors suggests that relatively simple models can be used to accurately predict large structural component weights for future launch vehicles.

Wettability, soil organic matter and structure-properties of typical chernozems under the forest and under the arable land

NASA Astrophysics Data System (ADS)

Bykova, Galina; Umarova, Aminat; Tyugai, Zemfira; Milanovskiy, Evgeny; Shein, Evgeny

2017-04-01

Intensive tillage affects the properties of soil: decrease in content of soil organic matter and in hydrophobicity of the soil's solid phase, the reduction of amount of water stable aggregates - all this leads to deterioration of the structure of the soil and affects the process of movement of moisture in the soil profile. One of the hypotheses of soil's structure formation ascribes the formation of water stable aggregates with the presence of hydrophobic organic substances on the surface of the soil's solid phase. The aim of this work is to study the effect of tillage on properties of typical chernozems (pachic Voronic Chernozems, Haplic Chernozems) (Russia, Kursk region), located under the forest and under the arable land. The determination of soil-water contact angle was performed by a Drop Shape Analyzer DSA100 (Krüss GmbH, Germany) by the static sessile drop method. For all samples the content of total and organic carbon by dry combustion in oxygen flow and the particle size distribution by the laser diffraction method on the device Analysette 22 comfort, FRITCH, Germany were determined. The estimation of aggregate composition was performed by dry sieving (AS 200, Retsch, Germany), the content of water stable aggregates was estimated by the Savvinov method. There was a positive correlation between the content of organic matter and soil's wettability in studied soils, a growth of contact angle with the increasing the content of organic matter. Under the forest the content of soil organic matter was changed from 6,41% on the surface up to 1,9% at the depth of 100 cm. In the Chernozem under the arable land the organic carbon content in arable horizon is almost two times less. The maximum of hydrophobicity (78.1o) was observed at the depth of 5 cm under the forest. In the profile under the arable land the contact angle value at the same depth was 50o. The results of the structure analysis has shown a decrease in the content of agronomically valuable and water

Factors Underlying Second Language Reading Motivation of Adult EAP Students

ERIC Educational Resources Information Center

Komiyama, Reiko

2013-01-01

Characteristics of English for Academic Purposes students' second language (L2) motivation were examined by identifying underlying motivational factors. Using the motivation constructs created by first language reading researchers, a survey was developed and administered to 2,018 students from 53 English language programs in the U.S. Survey…

Genetic Structure in the Seabuckthorn Carpenter Moth (Holcocerus hippophaecolus) in China: The Role of Outbreak Events, Geographical and Host Factors

PubMed Central

Tao, Jing; Chen, Min; Zong, Shi-Xiang; Luo, You-Qing

2012-01-01

Understanding factors responsible for structuring genetic diversity is of fundamental importance in evolutionary biology. The seabuckthorn carpenter moth (Holcocerus hippophaecolus Hua) is a native species throughout the north of China and is considered the main threat to seabuckthorn, Hippophae rhamnoides L. We assessed the influence of outbreaks, environmental factors and host species in shaping the genetic variation and structure of H. hippophaecolus by using Amplified Fragment Length Polymorphism (AFLP) markers. We rejected the hypothesis that outbreak-associated genetic divergence exist, as evidenced by genetic clusters containing a combination of populations from historical outbreak areas, as well as non-outbreak areas. Although a small number of markers (4 of 933 loci) were identified as candidates under selection in response to population densities. H. hippophaecolus also did not follow an isolation-by-distance pattern. We rejected the hypothesis that outbreak and drought events were driving the genetic structure of H. hippophaecolus. Rather, the genetic structure appears to be influenced by various confounding bio-geographical factors. There were detectable genetic differences between H. hippophaecolus occupying different host trees from within the same geographic location. Host-associated genetic divergence should be confirmed by further investigation. PMID:22291983

75 FR 80114 - Agency Information Collection (Obligation To Report Factors Affecting Entitlement) Activity Under...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-21

... (Obligation To Report Factors Affecting Entitlement) Activity Under OMB Review AGENCY: Veterans Benefits... Report Factors Affecting Entitlement (38 CFR 3.204(a)(1), 38 CFR 3.256(a) and 38 CFR 3.277(b)). OMB... benefits must report changes in their entitlement factors. Individual factors such as income, marital...

26 CFR 157.5891-1 - Imposition of excise tax on structured settlement factoring transactions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... settlement factoring transactions. 157.5891-1 Section 157.5891-1 Internal Revenue INTERNAL REVENUE SERVICE... SETTLEMENT FACTORING TRANSACTIONS Tax on Structured Settlement Factoring Transactions § 157.5891-1 Imposition of excise tax on structured settlement factoring transactions. (a) In general. Section 5891 imposes...

A guide to structural factors for advanced composites used on spacecraft

NASA Technical Reports Server (NTRS)

Vanwagenen, Robert

1989-01-01

The use of composite materials in spacecraft systems is constantly increasing. Although the areas of composite design and fabrication are maturing, they remain distinct from the same activities performed using conventional materials and processes. This has led to some confusion regarding the precise meaning of the term 'factor of safety' as it applies to these structures. In addition, composite engineering introduces terms such as 'knock-down factors' to further modify material properties for design purposes. This guide is intended to clarify these terms as well as their use in the design of composite structures for spacecraft. It is particularly intended to be used by the engineering community not involved in the day-to-day composites design process. An attempt is also made to explain the wide range of factors of safety encountered in composite designs as well as their relationship to the 1.4 factor of safety conventionally applied to metallic structures.

Energy Structure and Energy Security under Climate Mitigation Scenarios in China

PubMed Central

Matsumoto, Ken’ichi

2015-01-01

This study investigates how energy structure and energy security in China will change in the future under climate mitigation policy scenarios using Representative Concentration Pathways in a computable general equilibrium model. The findings suggest that to reduce greenhouse gas emissions, China needs to shift its energy structure from fossil fuel dominance to renewables and nuclear. The lower the allowable emissions, the larger the shifts required. Among fossil fuels, coal use particularly must significantly decrease. Such structural shifts will improve energy self-sufficiency, thus enhancing energy security. Under the policy scenarios, energy-source diversity as measured by the Herfindahl Index improves until 2050, after which diversity declines because of high dependence on a specific energy source (nuclear and biomass). Overall, however, it is revealed that energy security improves along with progress in climate mitigation. These improvements will also contribute to the economy by reducing energy procurement risks. PMID:26660094

Moving Aerospace Structural Design Practice to a Load and Resistance Factor Approach

NASA Technical Reports Server (NTRS)

Larsen, Curtis E.; Raju, Ivatury S.

2016-01-01

Aerospace structures are traditionally designed using the factor of safety (FOS) approach. The limit load on the structure is determined and the structure is then designed for FOS times the limit load - the ultimate load. Probabilistic approaches utilize distributions for loads and strengths. Failures are predicted to occur in the region of intersection of the two distributions. The load and resistance factor design (LRFD) approach judiciously combines these two approaches by intensive calibration studies on loads and strength to result in structures that are efficient and reliable. This paper discusses these three approaches.

Using Multilevel Factor Analysis with Clustered Data: Investigating the Factor Structure of the Positive Values Scale

ERIC Educational Resources Information Center

Huang, Francis L.; Cornell, Dewey G.

2016-01-01

Advances in multilevel modeling techniques now make it possible to investigate the psychometric properties of instruments using clustered data. Factor models that overlook the clustering effect can lead to underestimated standard errors, incorrect parameter estimates, and model fit indices. In addition, factor structures may differ depending on…

Local zeta factors and geometries under Spec Z

NASA Astrophysics Data System (ADS)

Manin, Yu I.

2016-08-01

The first part of this note shows that the odd-period polynomial of each Hecke cusp eigenform for the full modular group produces via the Rodriguez-Villegas transform ([1]) a polynomial satisfying the functional equation of zeta type and having non-trivial zeros only in the middle line of its critical strip. The second part discusses the Chebyshev lambda-structure of the polynomial ring as Borger's descent data to \\mathbf{F}_1 and suggests its role in a possible relation of the Γ\\mathbf{R}-factor to 'real geometry over \\mathbf{F}_1' (cf. [2]).

Factor Structure of Cognition and Functional Capacity in Two Studies of Schizophrenia and Bipolar Disorder: Implications for Genomic Studies

PubMed Central

Harvey, Philip D.; Aslan, Mihaela; Du, Mengtian; Zhao, Hongyu; Siever, Larry J.; Pulver, Ann; Gaziano, J. Michael; Concato, John

2015-01-01

Objective Impairments in cognition and everyday functioning are common in schizophrenia and bipolar disorder. Based on two studies of schizophrenia (SCZ) and bipolar I disorder (BPI) with similar methods, this paper presents factor analyses of cognitive and functional capacity (FC) measures. The overall goal of these analyses was to determine whether performance-based assessments should be examined individually, or aggregated on the basis of the correlational structure of the tests and as well as to evaluate the similarity of factor structures in SCZ and BPI. Method Veterans Affairs (VA) Cooperative Studies Program study #572, evaluated cognitive and FC measures among 5,414 BPI and 3,942 SZ patients. A second study evaluated similar neuropsychological (NP) and FC measures among 368 BPI and 436 SZ patients. Principal components analysis, as well as exploratory and confirmatory factor analyses, were used to examine the data. Results Analyses in both datasets suggested that NP and FC measures were explained by of a single underlying factor in BPI and SCZ patients, both when analyzed separately or as in a combined sample. The factor structure in both studies was similar, with or without inclusion of FC measures; homogeneous loadings were observed for that single factor across cognitive and FC domains across the samples. Conclusions The empirically derived factor model suggests that NP performance and FC are best explained as a single latent trait applicable to people with schizophrenia and bipolar illness. This single measure may enhance the robustness of the analyses relating genomic data to performance-based phenotypes. PMID:26710094

Atomic and electronic structure transformations of silver nanoparticles under rapid cooling conditions.

PubMed

Lobato, I; Rojas, J; Landauro, C V; Torres, J

2009-02-04

The structural evolution and dynamics of silver nanodrops Ag(2869) (4.4 nm in diameter) under rapid cooling conditions have been studied by means of molecular dynamics simulations and electronic density of state calculations. The interaction of silver atoms is modelled by a tight-binding semiempirical interatomic potential proposed by Cleri and Rosato. The pair correlation functions and the pair analysis technique are used to reveal the structural transition in the process of solidification. It is shown that Ag nanoparticles evolve into different nanostructures under different cooling processes. At a cooling rate of 1.5625 × 10(13) K s(-1) the nanoparticles preserve an amorphous-like structure containing a large amount of 1551 and 1541 pairs which correspond to icosahedral symmetry. For a lower cooling rate (1.5625 × 10(12) K s(-1)), the nanoparticles transform into a crystal-like structure consisting mainly of 1421 and 1422 pairs which correspond to the face centred cubic and hexagonal close packed structures, respectively. The variations of the electronic density of states for the differently cooled nanoparticles are small, but in correspondence with the structural changes.

Differences in within- and between-person factor structure of positive and negative affect: analysis of two intensive measurement studies using multilevel structural equation modeling.

PubMed

Rush, Jonathan; Hofer, Scott M

2014-06-01

The Positive and Negative Affect Schedule (PANAS) is a widely used measure of emotional experience. The factor structure of the PANAS has been examined predominantly with cross-sectional designs, which fails to disaggregate within-person variation from between-person differences. There is still uncertainty as to the factor structure of positive and negative affect and whether they constitute 2 distinct independent factors. The present study examined the within-person and between-person factor structure of the PANAS in 2 independent samples that reported daily affect over 7 and 14 occasions, respectively. Results from multilevel confirmatory factor analyses revealed that a 2-factor structure at both the within-person and between-person levels, with correlated specific factors for overlapping items, provided good model fit. The best-fitting solution was one where within-person factors of positive and negative affect were inversely correlated, but between-person factors were independent. The structure was further validated through multilevel structural equation modeling examining the effects of cognitive interference, daily stress, physical symptoms, and physical activity on positive and negative affect factors.

Examining the Factor Structure and Hierarchical Nature of the Quality of Life Construct

ERIC Educational Resources Information Center

Wang, Mian; Schalock, Robert L.; Verdugo, Miguel A.; Jenaro, Christina

2010-01-01

There is considerable debate in the area of individual quality of life research regarding the factor structure and hierarchical nature of the quality of life construct. Our purpose in this study was to test via structural equation modeling an a priori quality of life model consisting of eight first-order factors and one second-order factor. Data…

Enzyme That Makes You Cry-Crystal Structure of Lachrymatory Factor Synthase from Allium cepa.

PubMed

Silvaroli, Josie A; Pleshinger, Matthew J; Banerjee, Surajit; Kiser, Philip D; Golczak, Marcin

2017-09-15

The biochemical pathway that gives onions their savor is part of the chemical warfare against microbes and animals. This defense mechanism involves formation of a volatile lachrymatory factor (LF) ((Z)-propanethial S-oxide) that causes familiar eye irritation associated with onion chopping. LF is produced in a reaction catalyzed by lachrymatory factor synthase (LFS). The principles by which LFS facilitates conversion of a sulfenic acid substrate into LF have been difficult to experimentally examine owing to the inherent substrate reactivity and lability of LF. To shed light on the mechanism of LF production in the onion, we solved crystal structures of LFS in an apo-form and in complex with a substrate analogue, crotyl alcohol. The enzyme closely resembles the helix-grip fold characteristic for plant representatives of the START (star-related lipid transfer) domain-containing protein superfamily. By comparing the structures of LFS to that of the abscisic acid receptor, PYL10, a representative of the START protein superfamily, we elucidated structural adaptations underlying the catalytic activity of LFS. We also delineated the architecture of the active site, and based on the orientation of the ligand, we propose a mechanism of catalysis that involves sequential proton transfer accompanied by formation of a carbanion intermediate. These findings reconcile chemical and biochemical information regarding thioaldehyde S-oxide formation and close a long-lasting gap in understanding of the mechanism responsible for LF production in the onion.

Enzyme That Makes You Cry–Crystal Structure of Lachrymatory Factor Synthase from Allium cepa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silvaroli, Josie A.; Pleshinger, Matthew J.; Banerjee, Surajit

The biochemical pathway that gives onions their savor is part of the chemical warfare against microbes and animals. This defense mechanism involves formation of a volatile lachrymatory factor (LF) ((Z)-propanethial S-oxide) that causes familiar eye irritation associated with onion chopping. LF is produced in a reaction catalyzed by lachrymatory factor synthase (LFS). The principles by which LFS facilitates conversion of a sulfenic acid substrate into LF have been difficult to experimentally examine owing to the inherent substrate reactivity and lability of LF. To shed light on the mechanism of LF production in the onion, we solved crystal structures of LFSmore » in an apo-form and in complex with a substrate analogue, crotyl alcohol. The enzyme closely resembles the helix-grip fold characteristic for plant representatives of the START (star-related lipid transfer) domain-containing protein superfamily. By comparing the structures of LFS to that of the abscisic acid receptor, PYL10, a representative of the START protein superfamily, we elucidated structural adaptations underlying the catalytic activity of LFS. We also delineated the architecture of the active site, and based on the orientation of the ligand, we propose a mechanism of catalysis that involves sequential proton transfer accompanied by formation of a carbanion intermediate. These findings reconcile chemical and biochemical information regarding thioaldehyde S-oxide formation and close a long-lasting gap in understanding of the mechanism responsible for LF production in the onion.« less

Structure of rapidity divergences in multi-parton scattering soft factors

NASA Astrophysics Data System (ADS)

Vladimirov, Alexey

2018-04-01

We discuss the structure of rapidity divergences that are presented in the soft factors of transverse momentum dependent (TMD) factorization theorems. To provide the discussion on the most general level we consider soft factors for multi-parton scattering. We show that the rapidity divergences are result of the gluon exchanges with the distant transverse plane, and are structurally equivalent to the ultraviolet divergences. It allows to formulate and to prove the renormalization theorem for rapidity divergences. The proof is made with the help the conformal transformation which maps rapidity divergences to ultraviolet divergences. The theorem is the systematic form of the factorization of rapidity divergences, which is required for the definition of TMD parton distributions. In particular, the definition of multi parton distributions is presented. The equivalence of ultraviolet and rapidity divergences leads to the exact relation between soft and rapidity anomalous dimensions. Using this relation we derive the rapidity anomalous dimension at the three-loop order.

Tracking of Nuclear Cable Insulation Polymer Structural Changes using the Gel Fraction and Uptake Factor Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Correa, Miguel; Huang, Qian; Fifield, Leonard S.

Cross-linked polyethylene (XLPE) cable insulation samples were exposed to heat and gamma radiation at a series of temperatures, dose rates, and exposure times to evaluate the effects of these variables on material degradation. The samples were tested using the solvent incubation method to collect gel fraction and uptake factor data in order to assess the crosslinking and chain scission occurring in polymer samples with aging. Consistent with previous reports, gel fraction values were observed to increase and uptake factor values to decrease with radiation and thermal exposure. The trends seen were also more prominent as exposure time increased, suggesting thismore » to be a viable method of tracking structural changes in the XLPE-insulated cable material over extended periods. For the conditions explored, the cable insulation material evaluated did not indicate signs of anomalous aging such as inverse temperature effect in which radiation-induced aging is more severe at lower temperature. Ongoing aging under identical radiation conditions and at lower temperature will further inform conclusions regarding the importance of inverse temperature effects for this material under these conditions.« less

Social cognition in schizophrenia: Factor structure of emotion processing and theory of mind

PubMed Central

Browne, Julia; Penn, David L.; Raykov, Tenko; Pinkham, Amy E.; Kelsven, Skylar; Buck, Benjamin; Harvey, Philip D.

2018-01-01

Factor analytic studies examining social cognition in schizophrenia have yielded inconsistent results most likely due to the varying number and quality of measures. With the recent conclusion of Phase 3 of the Social Cognition Psychometric Evaluation (SCOPE) Study, the most psychometrically sound measures of social cognition have been identified. Therefore, the aims of the present study were to: 1) examine the factor structure of social cognition in schizophrenia through the utilization of psychometrically sound measures, 2) examine the stability of the factor structure across two study visits, 3) compare the factor structure of social cognition in schizophrenia to that in healthy controls, and 4) examine the relationship between the factors and relevant outcome measures including social functioning and symptoms. Results supported a one-factor model for the patient and healthy control samples at both visits. This single factor was significantly associated with negative symptoms in the schizophrenia sample and with social functioning in both groups at both study visits. PMID:27280525

Computational Study of Thrombus Formation and Clotting Factor Effects under Venous Flow Conditions

PubMed Central

Govindarajan, Vijay; Rakesh, Vineet; Reifman, Jaques; Mitrophanov, Alexander Y.

2016-01-01

A comprehensive understanding of thrombus formation as a physicochemical process that has evolved to protect the integrity of the human vasculature is critical to our ability to predict and control pathological states caused by a malfunctioning blood coagulation system. Despite numerous investigations, the spatial and temporal details of thrombus growth as a multicomponent process are not fully understood. Here, we used computational modeling to investigate the temporal changes in the spatial distributions of the key enzymatic (i.e., thrombin) and structural (i.e., platelets and fibrin) components within a growing thrombus. Moreover, we investigated the interplay between clot structure and its mechanical properties, such as hydraulic resistance to flow. Our model relied on the coupling of computational fluid dynamics and biochemical kinetics, and was validated using flow-chamber data from a previous experimental study. The model allowed us to identify the distinct patterns characterizing the spatial distributions of thrombin, platelets, and fibrin accumulating within a thrombus. Our modeling results suggested that under the simulated conditions, thrombin kinetics was determined predominantly by prothrombinase. Furthermore, our simulations showed that thrombus resistance imparted by fibrin was ∼30-fold higher than that imparted by platelets. Yet, thrombus-mediated bloodflow occlusion was driven primarily by the platelet deposition process, because the height of the platelet accumulation domain was approximately twice that of the fibrin accumulation domain. Fibrinogen supplementation in normal blood resulted in a nonlinear increase in thrombus resistance, and for a supplemented fibrinogen level of 48%, the thrombus resistance increased by ∼2.7-fold. Finally, our model predicted that restoring the normal levels of clotting factors II, IX, and X while simultaneously restoring fibrinogen (to 88% of its normal level) in diluted blood can restore fibrin generation to

Structural Rearrangement of Au-Pd Nanoparticles under Reaction Conditions: An ab Initio Molecular Dynamics Study.

PubMed

Xu, Cong-Qiao; Lee, Mal-Soon; Wang, Yang-Gang; Cantu, David C; Li, Jun; Glezakou, Vassiliki-Alexandra; Rousseau, Roger

2017-02-28

The structure, composition, and atomic distribution of nanoalloys under operating conditions are of significant importance for their catalytic activity. In the present work, we use ab initio molecular dynamics simulations to understand the structural behavior of Au-Pd nanoalloys supported on rutile TiO 2 under different conditions. We find that the Au-Pd structure is strongly dependent on the redox properties of the support, originating from strong metal-support interactions. Under reducing conditions, Pd atoms are inclined to move toward the metal/oxide interface, as indicated by a significant increase of Pd-Ti bonds. This could be attributed to the charge localization at the interface that leads to Coulomb attractions to positively charged Pd atoms. In contrast, under oxidizing conditions, Pd atoms would rather stay inside or on the exterior of the nanoparticle. Moreover, Pd atoms on the alloy surface can be stabilized by hydrogen adsorption, forming Pd-H bonds, which are stronger than Au-H bonds. Our work offers critical insights into the structure and redox properties of Au-Pd nanoalloy catalysts under working conditions.

Exploring the Underlying Factor Structure of the Home Literacy Environment (HLE) in the English and Spanish Versions of the Familia Inventory: A Cautionary Tale

ERIC Educational Resources Information Center

Gonzalez, Jorge E.; Taylor, Aaron B.; McCormick, Anita S.; Villareal, Victor; Kim, Minjung; Perez, Erica; Darensbourg, Alicia; Haynes, Rebekah

2011-01-01

Few research-based measures of the family literacy environment are commercially available, especially in Spanish. One exception is the Familia Inventory (Taylor, 1995). The present study investigated the 10 subscales of this instrument and the factor structure they imply, using data from a low-socioeconomic (SES), largely Hispanic population.…

Structural evolution of Colloidal Gels under Flow

NASA Astrophysics Data System (ADS)

Boromand, Arman; Maia, Joao; Jamali, Safa

Colloidal suspensions are ubiquitous in different industrial applications ranging from cosmetic and food industries to soft robotics and aerospace. Owing to the fact that mechanical properties of colloidal gels are controlled by its microstructure and network topology, we trace the particles in the networks formed under different attraction potentials and try to find a universal behavior in yielding of colloidal gels. Many authors have implemented different simulation techniques such as molecular dynamics (MD) and Brownian dynamics (BD) to capture better picture during phase separation and yielding mechanism in colloidal system with short-ranged attractive force. However, BD neglects multi-body hydrodynamic interactions (HI) which are believed to be responsible for the second yielding of colloidal gels. We envision using dissipative particle dynamics (DPD) with modified depletion potential and hydrodynamic interactions, as a coarse-grain model, can provide a robust simulation package to address the gel formation process and yielding in short ranged-attractive colloidal systems. The behavior of colloidal gels with different attraction potentials under flow is examined and structural fingerprints of yielding in these systems will be discussed.

Multi-objective shape optimization of plate structure under stress criteria based on sub-structured mixed FEM and genetic algorithms

NASA Astrophysics Data System (ADS)

Garambois, Pierre; Besset, Sebastien; Jézéquel, Louis

2015-07-01

This paper presents a methodology for the multi-objective (MO) shape optimization of plate structure under stress criteria, based on a mixed Finite Element Model (FEM) enhanced with a sub-structuring method. The optimization is performed with a classical Genetic Algorithm (GA) method based on Pareto-optimal solutions and considers thickness distributions parameters and antagonist objectives among them stress criteria. We implement a displacement-stress Dynamic Mixed FEM (DM-FEM) for plate structure vibrations analysis. Such a model gives a privileged access to the stress within the plate structure compared to primal classical FEM, and features a linear dependence to the thickness parameters. A sub-structuring reduction method is also computed in order to reduce the size of the mixed FEM and split the given structure into smaller ones with their own thickness parameters. Those methods combined enable a fast and stress-wise efficient structure analysis, and improve the performance of the repetitive GA. A few cases of minimizing the mass and the maximum Von Mises stress within a plate structure under a dynamic load put forward the relevance of our method with promising results. It is able to satisfy multiple damage criteria with different thickness distributions, and use a smaller FEM.

Structural behavior of supercritical fluids under confinement

NASA Astrophysics Data System (ADS)

Ghosh, Kanka; Krishnamurthy, C. V.

2018-01-01

The existence of the Frenkel line in the supercritical regime of a Lennard-Jones (LJ) fluid shown through molecular dynamics (MD) simulations initially and later corroborated by experiments on argon opens up possibilities of understanding the structure and dynamics of supercritical fluids in general and of the Frenkel line in particular. The location of the Frenkel line, which demarcates two distinct physical states, liquidlike and gaslike within the supercritical regime, has been established through MD simulations of the velocity autocorrelation (VACF) and radial distribution function (RDF). We, in this article, explore the changes in the structural features of supercritical LJ fluid under partial confinement using atomistic walls. The study is carried out across the Frenkel line through a series of MD simulations considering a set of thermodynamics states in the supercritical regime (P =5000 bar, 240 K ≤T ≤1500 K ) of argon well above the critical point. Confinement is partial, with atomistic walls located normal to z and extending to "infinity" along the x and y directions. In the "liquidlike" regime of the supercritical phase, particles are found to be distributed in distinct layers along the z axis with layer spacing less than one atomic diameter and the lateral RDF showing amorphous-like structure for specific spacings (packing frustration) and non-amorphous-like structure for other spacings. Increasing the rigidity of the atomistic walls is found to lead to stronger layering and increased structural order. For confinement with reflective walls, layers are found to form with one atomic diameter spacing and the lateral RDF showing close-packed structure for the smaller confinements. Translational order parameter and excess entropy assessment confirms the ordering taking place for atomistic wall and reflective wall confinements. In the "gaslike" regime of the supercritical phase, particle distribution along the spacing and the lateral RDF exhibit features

Structural behavior of supercritical fluids under confinement.

PubMed

Ghosh, Kanka; Krishnamurthy, C V

2018-01-01

The existence of the Frenkel line in the supercritical regime of a Lennard-Jones (LJ) fluid shown through molecular dynamics (MD) simulations initially and later corroborated by experiments on argon opens up possibilities of understanding the structure and dynamics of supercritical fluids in general and of the Frenkel line in particular. The location of the Frenkel line, which demarcates two distinct physical states, liquidlike and gaslike within the supercritical regime, has been established through MD simulations of the velocity autocorrelation (VACF) and radial distribution function (RDF). We, in this article, explore the changes in the structural features of supercritical LJ fluid under partial confinement using atomistic walls. The study is carried out across the Frenkel line through a series of MD simulations considering a set of thermodynamics states in the supercritical regime (P=5000 bar, 240K≤T≤1500K) of argon well above the critical point. Confinement is partial, with atomistic walls located normal to z and extending to "infinity" along the x and y directions. In the "liquidlike" regime of the supercritical phase, particles are found to be distributed in distinct layers along the z axis with layer spacing less than one atomic diameter and the lateral RDF showing amorphous-like structure for specific spacings (packing frustration) and non-amorphous-like structure for other spacings. Increasing the rigidity of the atomistic walls is found to lead to stronger layering and increased structural order. For confinement with reflective walls, layers are found to form with one atomic diameter spacing and the lateral RDF showing close-packed structure for the smaller confinements. Translational order parameter and excess entropy assessment confirms the ordering taking place for atomistic wall and reflective wall confinements. In the "gaslike" regime of the supercritical phase, particle distribution along the spacing and the lateral RDF exhibit features not

Neural Mechanisms Underlying the Computation of Hierarchical Tree Structures in Mathematics

PubMed Central

Nakai, Tomoya; Sakai, Kuniyoshi L.

2014-01-01

Whether mathematical and linguistic processes share the same neural mechanisms has been a matter of controversy. By examining various sentence structures, we recently demonstrated that activations in the left inferior frontal gyrus (L. IFG) and left supramarginal gyrus (L. SMG) were modulated by the Degree of Merger (DoM), a measure for the complexity of tree structures. In the present study, we hypothesize that the DoM is also critical in mathematical calculations, and clarify whether the DoM in the hierarchical tree structures modulates activations in these regions. We tested an arithmetic task that involved linear and quadratic sequences with recursive computation. Using functional magnetic resonance imaging, we found significant activation in the L. IFG, L. SMG, bilateral intraparietal sulcus (IPS), and precuneus selectively among the tested conditions. We also confirmed that activations in the L. IFG and L. SMG were free from memory-related factors, and that activations in the bilateral IPS and precuneus were independent from other possible factors. Moreover, by fitting parametric models of eight factors, we found that the model of DoM in the hierarchical tree structures was the best to explain the modulation of activations in these five regions. Using dynamic causal modeling, we showed that the model with a modulatory effect for the connection from the L. IPS to the L. IFG, and with driving inputs into the L. IFG, was highly probable. The intrinsic, i.e., task-independent, connection from the L. IFG to the L. IPS, as well as that from the L. IPS to the R. IPS, would provide a feedforward signal, together with negative feedback connections. We indicate that mathematics and language share the network of the L. IFG and L. IPS/SMG for the computation of hierarchical tree structures, and that mathematics recruits the additional network of the L. IPS and R. IPS. PMID:25379713

Factor structure of cognition and functional capacity in two studies of schizophrenia and bipolar disorder: Implications for genomic studies.

PubMed

Harvey, Philip D; Aslan, Mihaela; Du, Mengtian; Zhao, Hongyu; Siever, Larry J; Pulver, Ann; Gaziano, J Michael; Concato, John

2016-01-01

Impairments in cognition and everyday functioning are common in schizophrenia and bipolar disorder (BPD). In this article, we present factor analyses of cognitive and functional capacity (FC) measures based on 2 studies of schizophrenia (SCZ) and bipolar I disorder (BPI) using similar methods. The overall goal of these analyses was to determine whether performance-based assessments should be examined individually, or aggregated on the basis of the correlational structure of the tests, as well as to evaluate the similarity of factor structures of SCZ and BPI. Veterans Affairs Cooperative Studies Program Study #572 (Harvey et al., 2014) evaluated cognitive and FC measures among 5,414 BPI and 3,942 SCZ patients. A 2nd study evaluated similar neuropsychological (NP) and FC measures among 368 BPI and 436 SCZ patients. Principal components analysis, as well as exploratory and CFAs, were used to examine the data. Analyses in both datasets suggested that NP and FC measures were explained by a single underlying factor in BPI and SCZ patients, both when analyzed separately or as in a combined sample. The factor structure in both studies was similar, with or without inclusion of FC measures; homogeneous loadings were observed for that single factor across cognitive and FC domains across the samples. The empirically derived factor model suggests that NP performance and FC are best explained as a single latent trait applicable to people with SCZ and BPD. This single measure may enhance the robustness of the analyses relating genomic data to performance-based phenotypes. (c) 2015 APA, all rights reserved).

[Fine stereo structure for natural organic molecules, a preliminary study. II. Melting point influenced by structure factors].

PubMed

Lu, Y; Zheng, Q; Lu, D; Ma, P; Chen, Y

1995-06-01

Crystal structures of two compounds from Tripterygium wilfordii Hook f. have been determined by X-ray diffraction method. Structure factors influencing melting point of solid state have been analysed. Crystal class (or space group), recrystallization solvent, force between molecules and fine changes of molecular structures will all cause melting point changes of crystal substance.

Confirmatory factor analytic structure and measurement invariance of quantitative autistic traits measured by the social responsiveness scale-2.

PubMed

Frazier, Thomas W; Ratliff, Kristin R; Gruber, Chris; Zhang, Yi; Law, Paul A; Constantino, John N

2014-01-01

Understanding the factor structure of autistic symptomatology is critical to the discovery and interpretation of causal mechanisms in autism spectrum disorder. We applied confirmatory factor analysis and assessment of measurement invariance to a large (N = 9635) accumulated collection of reports on quantitative autistic traits using the Social Responsiveness Scale, representing a broad diversity of age, severity, and reporter type. A two-factor structure (corresponding to social communication impairment and restricted, repetitive behavior) as elaborated in the updated Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) criteria for autism spectrum disorder exhibited acceptable model fit in confirmatory factor analysis. Measurement invariance was appreciable across age, sex, and reporter (self vs other), but somewhat less apparent between clinical and nonclinical populations in this sample comprised of both familial and sporadic autism spectrum disorders. The statistical power afforded by this large sample allowed relative differentiation of three factors among items encompassing social communication impairment (emotion recognition, social avoidance, and interpersonal relatedness) and two factors among items encompassing restricted, repetitive behavior (insistence on sameness and repetitive mannerisms). Cross-trait correlations remained extremely high, that is, on the order of 0.66-0.92. These data clarify domains of statistically significant factoral separation that may relate to partially-but not completely-overlapping biological mechanisms, contributing to variation in human social competency. Given such robust intercorrelations among symptom domains, understanding their co-emergence remains a high priority in conceptualizing common neural mechanisms underlying autistic syndromes.

Algorithms for Determining Physical Responses of Structures Under Load

NASA Technical Reports Server (NTRS)

Richards, W. Lance; Ko, William L.

2012-01-01

Ultra-efficient real-time structural monitoring algorithms have been developed to provide extensive information about the physical response of structures under load. These algorithms are driven by actual strain data to measure accurately local strains at multiple locations on the surface of a structure. Through a single point load calibration test, these structural strains are then used to calculate key physical properties of the structure at each measurement location. Such properties include the structure s flexural rigidity (the product of the structure's modulus of elasticity, and its moment of inertia) and the section modulus (the moment of inertia divided by the structure s half-depth). The resulting structural properties at each location can be used to determine the structure s bending moment, shear, and structural loads in real time while the structure is in service. The amount of structural information can be maximized through the use of highly multiplexed fiber Bragg grating technology using optical time domain reflectometry and optical frequency domain reflectometry, which can provide a local strain measurement every 10 mm on a single hair-sized optical fiber. Since local strain is used as input to the algorithms, this system serves multiple purposes of measuring strains and displacements, as well as determining structural bending moment, shear, and loads for assessing real-time structural health. The first step is to install a series of strain sensors on the structure s surface in such a way as to measure bending strains at desired locations. The next step is to perform a simple ground test calibration. For a beam of length l (see example), discretized into n sections and subjected to a tip load of P that places the beam in bending, the flexural rigidity of the beam can be experimentally determined at each measurement location x. The bending moment at each station can then be determined for any general set of loads applied during operation.

Factor structure of PTSD, and relation with gender in trauma survivors from India.

PubMed

Charak, Ruby; Armour, Cherie; Elklit, Ask; Angmo, Disket; Elhai, Jon D; Koot, Hans M

2014-01-01

The factor structure of posttraumatic stress disorder (PTSD) has been extensively studied in Western countries. Some studies have assessed its factor structure in Asia (China, Sri Lanka, and Malaysia), but few have directly assessed the factor structure of PTSD in an Indian adult sample. Furthermore, in a largely patriarchal society in India with strong gender roles, it becomes imperative to assess the association between the factors of PTSD and gender. The purpose of the present study was to assess the factor structure of PTSD in an Indian sample of trauma survivors based on prevailing models of PTSD defined in the DSM-IV-TR (APA, 2000), and to assess the relation between PTSD factors and gender. The sample comprised of 313 participants (55.9% female) from Jammu and Kashmir, India, who had experienced a natural disaster (N=200) or displacement due to cross-border firing (N=113). Three existing PTSD models-two four-factor models (Emotional Numbing and Dysphoria), and a five-factor model (Dysphoric Arousal)-were tested using Confirmatory Factor Analysis with addition of gender as a covariate. The three competing models had similar fit indices although the Dysphoric Arousal model fit significantly better than Emotional Numbing and Dysphoria models. Gender differences were found across the factors of Re-experiencing and Anxious arousal. Findings indicate that the Dysphoric Arousal model of PTSD was the best model; albeit the fit indices of all models were fairly similar. Compared to males, females scored higher on factors of Re-experiencing and Anxious arousal. Gender differences found across two factors of PTSD are discussed in light of the social milieu in India.

Factor structure of PTSD, and relation with gender in trauma survivors from India

PubMed Central

Charak, Ruby; Armour, Cherie; Elklit, Ask; Angmo, Disket; Elhai, Jon D.; Koot, Hans M.

2014-01-01

Background The factor structure of posttraumatic stress disorder (PTSD) has been extensively studied in Western countries. Some studies have assessed its factor structure in Asia (China, Sri Lanka, and Malaysia), but few have directly assessed the factor structure of PTSD in an Indian adult sample. Furthermore, in a largely patriarchal society in India with strong gender roles, it becomes imperative to assess the association between the factors of PTSD and gender. Objective The purpose of the present study was to assess the factor structure of PTSD in an Indian sample of trauma survivors based on prevailing models of PTSD defined in the DSM-IV-TR (APA, 2000), and to assess the relation between PTSD factors and gender. Method The sample comprised of 313 participants (55.9% female) from Jammu and Kashmir, India, who had experienced a natural disaster (N=200) or displacement due to cross-border firing (N=113). Results Three existing PTSD models—two four-factor models (Emotional Numbing and Dysphoria), and a five-factor model (Dysphoric Arousal)—were tested using Confirmatory Factor Analysis with addition of gender as a covariate. The three competing models had similar fit indices although the Dysphoric Arousal model fit significantly better than Emotional Numbing and Dysphoria models. Gender differences were found across the factors of Re-experiencing and Anxious arousal. Conclusions Findings indicate that the Dysphoric Arousal model of PTSD was the best model; albeit the fit indices of all models were fairly similar. Compared to males, females scored higher on factors of Re-experiencing and Anxious arousal. Gender differences found across two factors of PTSD are discussed in light of the social milieu in India. PMID:25413575

Plant cell plasma membrane structure and properties under clinostatting

NASA Astrophysics Data System (ADS)

Polulakh, Yu. A.; Zhadko, S. I.; Klimchuk, D. A.; Baraboy, V. A.; Alpatov, A. N.; Sytnik, K. M.

Structural-functional organization of plasma membrane of pea roots seedling was investigated by methods of chemiluminescence, fluorescence probes, chromatography and freeze-fracture studies under normal conditions and clinostatting. Phase character of lipid peroxidation intensity was fixed. The initial phase of this process is characterized by lipid peroxidation decreasing with its next induction. The primary changes depending on free-radical mechanisms of lipid peroxidation were excellently revealed by chemiluminescence. Plasmalemma microviscosity increased on the average of 15-20 % under microgravity at the initial stages of its phenomenon. There were major changes of phosphatidilcholine and phosphatidilethanolamine contents. The total quantity of phospholipids remained rather stable. Changes of phosphatide acid concentration point to degradation and phospholipids biosynthesis. There were increases of unsaturated fatty acids mainly at the expense of linoleic and linolenic acids and also a decrease of saturated fatty acid content at the expense of palmitic and stearic acids. Unsaturation index of fatty acids increased as well. On the whole fatty acid composition was variable in comparison with phospholipids. Probably it is one of mechanisms of maintaining of microviscosity within definite limits. Considerable structural changes in organization of plasmalemma protein-lipid complex were not revealed by the freeze-fracture studies.

Perturbation of Chromatin Structure Globally Affects Localization and Recruitment of Splicing Factors

PubMed Central

Risso, Guillermo J.; Pawellek, Andrea; Ule, Jernej; Lamond, Angus I.; Kornblihtt, Alberto R.

2012-01-01

Chromatin structure is an important factor in the functional coupling between transcription and mRNA processing, not only by regulating alternative splicing events, but also by contributing to exon recognition during constitutive splicing. We observed that depolarization of neuroblastoma cell membrane potential, which triggers general histone acetylation and regulates alternative splicing, causes a concentration of SR proteins in nuclear speckles. This prompted us to analyze the effect of chromatin structure on splicing factor distribution and dynamics. Here, we show that induction of histone hyper-acetylation results in the accumulation in speckles of multiple splicing factors in different cell types. In addition, a similar effect is observed after depletion of the heterochromatic protein HP1α, associated with repressive chromatin. We used advanced imaging approaches to analyze in detail both the structural organization of the speckle compartment and nuclear distribution of splicing factors, as well as studying direct interactions between splicing factors and their association with chromatin in vivo. The results support a model where perturbation of normal chromatin structure decreases the recruitment efficiency of splicing factors to nascent RNAs, thus causing their accumulation in speckles, which buffer the amount of free molecules in the nucleoplasm. To test this, we analyzed the recruitment of the general splicing factor U2AF65 to nascent RNAs by iCLIP technique, as a way to monitor early spliceosome assembly. We demonstrate that indeed histone hyper-acetylation decreases recruitment of U2AF65 to bulk 3′ splice sites, coincident with the change in its localization. In addition, prior to the maximum accumulation in speckles, ∼20% of genes already show a tendency to decreased binding, while U2AF65 seems to increase its binding to the speckle-located ncRNA MALAT1. All together, the combined imaging and biochemical approaches support a model where chromatin

The Network Structure of Human Personality According to the NEO-PI-R: Matching Network Community Structure to Factor Structure

PubMed Central

Goekoop, Rutger; Goekoop, Jaap G.; Scholte, H. Steven

2012-01-01

Introduction Human personality is described preferentially in terms of factors (dimensions) found using factor analysis. An alternative and highly related method is network analysis, which may have several advantages over factor analytic methods. Aim To directly compare the ability of network community detection (NCD) and principal component factor analysis (PCA) to examine modularity in multidimensional datasets such as the neuroticism-extraversion-openness personality inventory revised (NEO-PI-R). Methods 434 healthy subjects were tested on the NEO-PI-R. PCA was performed to extract factor structures (FS) of the current dataset using both item scores and facet scores. Correlational network graphs were constructed from univariate correlation matrices of interactions between both items and facets. These networks were pruned in a link-by-link fashion while calculating the network community structure (NCS) of each resulting network using the Wakita Tsurumi clustering algorithm. NCSs were matched against FS and networks of best matches were kept for further analysis. Results At facet level, NCS showed a best match (96.2%) with a ‘confirmatory’ 5-FS. At item level, NCS showed a best match (80%) with the standard 5-FS and involved a total of 6 network clusters. Lesser matches were found with ‘confirmatory’ 5-FS and ‘exploratory’ 6-FS of the current dataset. Network analysis did not identify facets as a separate level of organization in between items and clusters. A small-world network structure was found in both item- and facet level networks. Conclusion We present the first optimized network graph of personality traits according to the NEO-PI-R: a ‘Personality Web’. Such a web may represent the possible routes that subjects can take during personality development. NCD outperforms PCA by producing plausible modularity at item level in non-standard datasets, and can identify the key roles of individual items and clusters in the network. PMID:23284713

The network structure of human personality according to the NEO-PI-R: matching network community structure to factor structure.

PubMed

Goekoop, Rutger; Goekoop, Jaap G; Scholte, H Steven

2012-01-01

Human personality is described preferentially in terms of factors (dimensions) found using factor analysis. An alternative and highly related method is network analysis, which may have several advantages over factor analytic methods. To directly compare the ability of network community detection (NCD) and principal component factor analysis (PCA) to examine modularity in multidimensional datasets such as the neuroticism-extraversion-openness personality inventory revised (NEO-PI-R). 434 healthy subjects were tested on the NEO-PI-R. PCA was performed to extract factor structures (FS) of the current dataset using both item scores and facet scores. Correlational network graphs were constructed from univariate correlation matrices of interactions between both items and facets. These networks were pruned in a link-by-link fashion while calculating the network community structure (NCS) of each resulting network using the Wakita Tsurumi clustering algorithm. NCSs were matched against FS and networks of best matches were kept for further analysis. At facet level, NCS showed a best match (96.2%) with a 'confirmatory' 5-FS. At item level, NCS showed a best match (80%) with the standard 5-FS and involved a total of 6 network clusters. Lesser matches were found with 'confirmatory' 5-FS and 'exploratory' 6-FS of the current dataset. Network analysis did not identify facets as a separate level of organization in between items and clusters. A small-world network structure was found in both item- and facet level networks. We present the first optimized network graph of personality traits according to the NEO-PI-R: a 'Personality Web'. Such a web may represent the possible routes that subjects can take during personality development. NCD outperforms PCA by producing plausible modularity at item level in non-standard datasets, and can identify the key roles of individual items and clusters in the network.

Probabilistic simulation of the human factor in structural reliability

NASA Technical Reports Server (NTRS)

Chamis, C. C.

1993-01-01

A formal approach is described in an attempt to computationally simulate the probable ranges of uncertainties of the human factor in structural probabilistic assessments. A multi-factor interaction equation (MFIE) model has been adopted for this purpose. Human factors such as marital status, professional status, home life, job satisfaction, work load and health, are considered to demonstrate the concept. Parametric studies in conjunction with judgment are used to select reasonable values for the participating factors (primitive variables). Suitability of the MFIE in the subsequently probabilistic sensitivity studies are performed to assess the validity of the whole approach. Results obtained show that the uncertainties for no error range from five to thirty percent for the most optimistic case.

Factor structure of the Korean version of illness intrusiveness rating scale: cross-cultural implications.

PubMed

Kim, Daeho; Kim, Kwang-iel; Lee, Haewon; Choi, Joonho; Park, Yong-Chon

2005-04-01

The Illness Intrusiveness Rating Scale (IIRS) measures illness-induced disruptions to 13 domains of lifestyles, activities, and interests. A stable three-factor structure has been well documented; however, the cross-cultural validity of this scale needs to be tested. This study investigated the factor structure of the Korean version of IIRS in 712 outpatients at a university medical center. A predominant diagnosis of the patients was rheumatoid arthritis (47%). The Center for Epidemiological Studies-Depression Scale (CES-D), and Health Assessment Questionnaire (HAQ) were also administered. Exploratory Principal Component Analysis identified a two-factor structure, "Relationships and Personal Development (RPD)" and "Instrumental", accounting for 57% of the variance. Confirmatory analyses extracted an identical factor structure. However, a goodness-of-the fit test failed to support two-factor solution (chi(2)=138.2, df=43, p<.001). Two factors had high internal consistency (RPD, alpha=.89; Instrumental, alpha=.75) and significantly correlated with scores of HAQ (RPD, r=.53, p<.001; Instrumental, .r=44, p<.001) and CES-D (RPD, .r=55, p<.001; Instrumental, .r=43, p<.001). These findings supported construct validity of the Korean version of IIRS, but did not support cross-cultural equivalence of the factor structure.

Factor Structure of the Korean Version of Illness Intrusiveness Rating Scale: Cross-cultural Implications

PubMed Central

Kim, Kwang-iel; Lee, Haewon; Choi, Joonho; Park, Yong-Chon

2005-01-01

The Illness Intrusiveness Rating Scale (IIRS) measures illness-induced disruptions to 13 domains of lifestyles, activities, and interests. A stable three-factor structure has been well documented; however, the cross-cultural validity of this scale needs to be tested. This study investigated the factor structure of the Korean version of IIRS in 712 outpatients at a university medical center. A predominant diagnosis of the patients was rheumatoid arthritis (47%). The Center for Epidemiological Studies-Depression Scale (CES-D), and Health Assessment Questionnaire (HAQ) were also administered. Exploratory Principal Component Analysis identified a two-factor structure, "Relationships and Personal Development (RPD)" and "Instrumental", accounting for 57% of the variance. Confirmatory analyses extracted an identical factor structure. However, a goodness-of-the fit test failed to support two-factor solution (χ2=138.2, df=43, p<.001). Two factors had high internal consistency (RPD, α=.89; Instrumental, α=.75) and significantly correlated with scores of HAQ (RPD, r=.53, p<.001; Instrumental, .r=44, p<.001) and CES-D (RPD, .r=55, p<.001; Instrumental, .r=43, p<.001). These findings supported construct validity of the Korean version of IIRS, but did not support cross-cultural equivalence of the factor structure. PMID:15832005

The p Factor: One General Psychopathology Factor in the Structure of Psychiatric Disorders?

PubMed Central

Caspi, Avshalom; Houts, Renate M.; Belsky, Daniel W.; Goldman-Mellor, Sidra J.; Harrington, HonaLee; Israel, Salomon; Meier, Madeline H.; Ramrakha, Sandhya; Shalev, Idan; Poulton, Richie; Moffitt, Terrie E.

2013-01-01

Mental disorders traditionally have been viewed as distinct, episodic, and categorical conditions. This view has been challenged by evidence that many disorders are sequentially comorbid, recurrent/chronic, and exist on a continuum. Using the Dunedin Multidisciplinary Health and Development Study, we examined the structure of psychopathology, taking into account dimensionality, persistence, co-occurrence, and sequential comorbidity of mental disorders across 20 years, from adolescence to midlife. Psychiatric disorders were initially explained by three higher-order factors (Internalizing, Externalizing, and Thought Disorder) but explained even better with one General Psychopathology dimension. We have called this dimension the p factor because it conceptually parallels a familiar dimension in psychological science: the g factor of general intelligence. Higher p scores are associated with more life impairment, greater familiality, worse developmental histories, and more compromised early-life brain function. The p factor explains why it is challenging to find causes, consequences, biomarkers, and treatments with specificity to individual mental disorders. Transdiagnostic approaches may improve research. PMID:25360393

The underlying structure of skin wrinkles: a hyperspectral approach to crows feet

NASA Astrophysics Data System (ADS)

Puccetti, G.

2017-02-01

Skin wrinkles are visually perceived by consumers but they are also known to possess an underlying structure not apparent at the surface of the skin. This underlying structure can be brought out by polarized hyperspectral imaging. Wrinkle patterns of eye crow's feet are used as example to show a deeper existing pattern and their characterization versus age on a group of volunteers. The skin inhomogeneity changes within each layer of the skin and can be observed in the shorter wavelength region of the spectrum, about 450nm to 500nm which are well suited to image skin surface inhomogeneities within the central and deep epidermis. Imaging in the 550nm range can serve as a larger scale topology reference because of its deeper penetration into the upper dermis. This serves to bring out the underlying wrinkle pattern as imprinted by collagen anisotropies around deep folds but unapparent to the eye yet. The approach has potential applications in evaluating the internal skin patterns non visible to the eye by mapping their spectral dispersion. This method has thus potentials to evaluate the extent of subsurface structures such as acne and other scars and thereby the efficacy of treatments.

The Recruitment of Social Movement Leaders: Structural Factors.

ERIC Educational Resources Information Center

Himes, Joseph S.

1979-01-01

A review of pertinent literature indicates that social movements produce their leaders by transforming and transferring some followers into the roles of leadership. A case study of the recruitment of social movement leaders in Rhodesia supports this hypothesis and illustrates some of the structural factors which condition the process. (EB)

[Analysis on risk factors of endotracheal cuff under inflation in mechanically ventilated patients].

PubMed

Fu, You; Xi, Xiuming

2014-12-01

To investigate the prevalent condition of endotracheal cuff pressure and risk factors for under inflation. A prospective cohort study was conducted. Patients admitted to the Department of Critical Care Medicine of Fuxing Hospital Affiliated to Capital Medical University, who were intubated with a high-volume low-pressure endotracheal tube, and had undergone mechanical ventilation for at least 48 hours, were enrolled. The endotracheal cuff pressure was determined every 8 hours by a manual manometer connected to the distal edge of the valve cuff at 07 : 00, 15 : 00, and 23 : 00. Measurement of the endotracheal cuff pressure was continued until the extubation of endotracheal or tracheostomy tube, or death of the patient. According to the incidence of under inflation of endotracheal cuff, patients were divided into the incidence of under inflation lower than 25% group (lower low cuff pressure group) and higher than 25% group (higher low cuff pressure group). The possible influencing factors were evaluated in the two groups, including body mass index (BMI), size of endotracheal tube, duration of intubation, use of sedative or analgesic, number of leaving from intensive care unit (ICU), the number of turning over the patients, and aspiration of sputum. Logistic regression analysis was used to determine risk factors for under-inflation of the endotracheal cuff. During the study period, 53 patients were enrolled. There were 812 measurements, and 46.3% of them was abnormal, and 204 times (25.1%) of under inflation of endotracheal cuff were found. There were 24 patients (45.3%) in whom the incidence of under inflation rate was higher than 25%. The average of under inflation was 7 (4, 10) times. Compared with the group with lower rate of low cuff pressure, a longer time for intubation was found in group with higher rate of low cuff pressure [hours: 162 (113, 225) vs. 118 (97, 168), Z=-2.034, P=0.042]. There were no differences between the two groups in other factors

Social cognition in schizophrenia: Factor structure of emotion processing and theory of mind.

PubMed

Browne, Julia; Penn, David L; Raykov, Tenko; Pinkham, Amy E; Kelsven, Skylar; Buck, Benjamin; Harvey, Philip D

2016-08-30

Factor analytic studies examining social cognition in schizophrenia have yielded inconsistent results most likely due to the varying number and quality of measures. With the recent conclusion of Phase 3 of the Social Cognition Psychometric Evaluation (SCOPE) Study, the most psychometrically sound measures of social cognition have been identified. Therefore, the aims of the present study were to: 1) examine the factor structure of social cognition in schizophrenia through the utilization of psychometrically sound measures, 2) examine the stability of the factor structure across two study visits, 3) compare the factor structure of social cognition in schizophrenia to that in healthy controls, and 4) examine the relationship between the factors and relevant outcome measures including social functioning and symptoms. Results supported a one-factor model for the patient and healthy control samples at both visits. This single factor was significantly associated with negative symptoms in the schizophrenia sample and with social functioning in both groups at both study visits. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Unequal density effect on static structure factor of coupled electron layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saini, L. K., E-mail: lks@ashd.svnit.ac.in; Nayak, Mukesh G., E-mail: lks@ashd.svnit.ac.in

In order to understand the ordered phase, if any, in a real coupled electron layers (CEL), there is a need to take into account the effect of unequal layer density. Such phase is confirmed by a strong peak in a static structure factor. With the aid of quantum/dynamical version of Singwi, Tosi, Land and Sjölander (so-called qSTLS) approximation, we have calculated the intra- and interlayer static structure factors, S{sub ll}(q) and S{sub 12}(q), over a wide range of density parameter r{sub sl} and interlayer spacing d. In our present study, the sharp peak in S{sub 22}(q) has been found atmore » critical density with sufficiently lower interlayer spacing. Further, to find the resultant effect of unequal density on intra- and interlayer static structure factors, we have compared our results with that of the recent CEL system with equal layer density and isolated single electron layer.« less

Structural analysis of the human fibroblast growth factor receptor 4 kinase.

PubMed

Lesca, E; Lammens, A; Huber, R; Augustin, M

2014-11-11

The family of fibroblast growth factor receptors (FGFRs) plays an important and well-characterized role in a variety of pathological disorders. FGFR4 is involved in myogenesis and muscle regeneration. Mutations affecting the kinase domain of FGFR4 may cause cancer, for example, breast cancer or rhabdomyosarcoma. Whereas FGFR1-FGFR3 have been structurally characterized, the structure of the FGFR4 kinase domain has not yet been reported. In this study, we present four structures of the kinase domain of FGFR4, in its apo-form and in complex with different types of small-molecule inhibitors. The two apo-FGFR4 kinase domain structures show an activation segment similar in conformation to an autoinhibitory segment observed in the hepatocyte growth factor receptor kinase but different from the known structures of other FGFR kinases. The structures of FGFR4 in complex with the type I inhibitor Dovitinib and the type II inhibitor Ponatinib reveal the molecular interactions with different types of kinase inhibitors and may assist in the design and development of FGFR4 inhibitors. Copyright © 2014 Elsevier Ltd. All rights reserved.

In situ structural analysis of calcium aluminosilicate glasses under high pressure.

PubMed

Muniz, R F; de Ligny, D; Martinet, C; Sandrini, M; Medina, A N; Rohling, J H; Baesso, M L; Lima, S M; Andrade, L H C; Guyot, Y

2016-08-10

In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH(-)-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ([Formula: see text][T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q (n) species to Q (n-1). In the case of Al-rich glass, the Al in the smallest Q (n) units evolved from tetrahedral to higher-coordinated Al (([5])Al and ([6])Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.

Multi-walled carbon nanotube structural instability with/without metal nanoparticles under electron beam irradiation

NASA Astrophysics Data System (ADS)

Khan, Imran; Huang, Shengli; Wu, Chenxu

2017-12-01

The structural transformation of multi-walled carbon nanotubes (MWCNT) under electron beam (e-beam) irradiation at room temperature is studied, with respect to a novel passivation effect due to gold nanoparticles (Au NPs). MWCNT structural evolution induced by energetic e-beam irradiation leads to faster shrinkage, as revealed via in situ transmission electron microscopy, while MWCNT surface modification with Au NPs (Au-MWCNT) slows down the shrinkage by impeding the structural evolution process for a prolonged time under the same irradiation conditions. The new relationship between MWCNT and Au-MWCNT shrinking radii and irradiation time illustrates that the MWCNT shrinkage rate is faster than either theoretical predictions or the same process in Au-MWCNTs. As compared with the outer surface energy (positive curvature), the inner surface energy (negative curvature) of the MWCNT contributes more to the athermal evaporation of tube wall atoms, leading to structural instability and shrinkage under e-beam irradiation. Conversely, Au NPs possess only outer surface energy (positive curvature) compared with the MWCNT. Their presence on MWCNT surfaces retards the dynamics of MWCNT structural evolution by slowing down the evaporation process of carbon atoms, thus restricting Au-MWCNT shrinkage. Au NP interaction and growth evolves athermally on MWCNT surfaces, exhibits increase in their size, and indicates the association of this mechanism with the coalescence induced by e-beam activated electronic excitations. Despite their growth, Au NPs show extreme structural stability, and remain crystalline under prolonged irradiation. It is proposed that the surface energy of MWCNTs and Au NPs, together with e-beam activated soft modes or lattice instability effects, predominantly govern all the above varieties of structural evolution.

Risk and contributing factors of ecosystem shifts over naturally vegetated land under climate change in China

PubMed Central

Yin, Yuanyuan; Tang, Qiuhong; Wang, Lixin; Liu, Xingcai

2016-01-01

Identifying the areas at risk of ecosystem transformation and the main contributing factors to the risk is essential to assist ecological adaptation to climate change. We assessed the risk of ecosystem shifts in China using the projections of four global gridded vegetation models (GGVMs) and an aggregate metric. The results show that half of naturally vegetated land surface could be under moderate or severe risk at the end of the 21st century under the middle and high emission scenarios. The areas with high risk are the Tibetan Plateau region and an area extended northeastward from the Tibetan Plateau to northeast China. With the three major factors considered, the change in carbon stocks is the main contributing factor to the high risk of ecosystem shifts. The change in carbon fluxes is another important contributing factor under the high emission scenario. The change in water fluxes is a less dominant factor except for the Tibetan Plateau region under the high emission scenario. Although there is considerable uncertainty in the risk assessment, the geographic patterns of the risk are generally consistent across different scenarios. The results could help develop regional strategies for ecosystem conservation to cope with climate change. PMID:26867481

Risk and contributing factors of ecosystem shifts over naturally vegetated land under climate change in China.

PubMed

Yin, Yuanyuan; Tang, Qiuhong; Wang, Lixin; Liu, Xingcai

2016-02-12

Identifying the areas at risk of ecosystem transformation and the main contributing factors to the risk is essential to assist ecological adaptation to climate change. We assessed the risk of ecosystem shifts in China using the projections of four global gridded vegetation models (GGVMs) and an aggregate metric. The results show that half of naturally vegetated land surface could be under moderate or severe risk at the end of the 21(st) century under the middle and high emission scenarios. The areas with high risk are the Tibetan Plateau region and an area extended northeastward from the Tibetan Plateau to northeast China. With the three major factors considered, the change in carbon stocks is the main contributing factor to the high risk of ecosystem shifts. The change in carbon fluxes is another important contributing factor under the high emission scenario. The change in water fluxes is a less dominant factor except for the Tibetan Plateau region under the high emission scenario. Although there is considerable uncertainty in the risk assessment, the geographic patterns of the risk are generally consistent across different scenarios. The results could help develop regional strategies for ecosystem conservation to cope with climate change.

Structural transformations in Ge{sub 2}Sb{sub 2}Te{sub 5} under high pressure and temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mio, A. M.; Privitera, S., E-mail: stefania.privitera@imm.cnr.it; D'Arrigo, G.

2015-08-14

The structural transformations occurring in Ge{sub 2}Sb{sub 2}Te{sub 5} films heated at temperature up to 400 °C, and under hydrostatic pressure up to 12 GPa, have been investigated through in-situ X ray diffraction measurements. The adopted experimental conditions are close to those experienced by the phase change material during the SET (crystallization)/RESET (amorphization) processes in a nonvolatile memory device. The compression enhances the thermal stability of the amorphous phase, which remains stable up to 180 °C at 8 GPa and to 230 °C at 12 GPa. The structure of the crystalline phases is also modified, with the formation of a CsCl-type structure instead of rock-salt andmore » of a GeS-type structure at the temperature at which usually the trigonal stable phase is formed. Overall, the stability of the stable phase appears to be more affected by the compression. We argue that the presence of weak bonds associated to the van der Waals gaps is a determining factor for the observed reduced stability.« less

Factor analysis of the Mayo-Portland Adaptability Inventory: structure and validity.

PubMed

Bohac, D L; Malec, J F; Moessner, A M

1997-07-01

Principal-components (PC) factor analysis of the Mayo-Portland Adaptability Inventory (MPAI) was conducted using a sample of outpatients (n = 189) with acquired brain injury (ABI) to evaluate whether outcome after ABI is multifactorial or unifactorial in nature. An eight-factor model was derived which explained 64-4% of the total variance. The eight factors were interpreted as representing Activities of Daily Living, Social Initiation, Cognition, Impaired-Self-awareness/Distress, Social Skills/ Support, Independence, Visuoperceptual, and Psychiatric, respectively. Validation of the Cognition factor was supported when factor scores were correlated with various neuropsychological measures. In addition, 117 patient self-rating total scores were used to evaluate the Impaired Self-awareness/Distress factor. An inverse relationship was observed, supporting this factor's ability to capture the two-dimensional phenomena of diminished self-awareness or enhanced emotional distress. A new subscale structure is suggested, that may allow greater clinical utility in understanding how ABI manifests in patients, and may provide clinicians with a better structure for implementing treatment strategies to address specific areas of impairment and disability for specific patients. Additionally, more precise measurement of treatment outcomes may be afforded by this reorganization.

Capture of endothelial cells under flow using immobilized vascular endothelial growth factor

PubMed Central

Smith, Randall J.; Koobatian, Maxwell T.; Shahini, Aref; Swartz, Daniel D.; Andreadis, Stelios T.

2015-01-01

We demonstrate the ability of immobilized vascular endothelial growth factor (VEGF) to capture endothelial cells (EC) with high specificity under fluid flow. To this end, we engineered a surface consisting of heparin bound to poly-L-lysine to permit immobilization of VEGF through the C-terminal heparin-binding domain. The immobilized growth factor retained its biological activity as shown by proliferation of EC and prolonged activation of KDR signaling. Using a microfluidic device we assessed the ability to capture EC under a range of shear stresses from low (0.5 dyne/cm2) to physiological (15 dyne/cm2). Capture was significant for all shear stresses tested. Immobilized VEGF was highly selective for EC as evidenced by significant capture of human umbilical vein and ovine pulmonary artery EC but no capture of human dermal fibroblasts, human hair follicle derived mesenchymal stem cells, or mouse fibroblasts. Further, VEGF could capture EC from mixtures with non-EC under low and high shear conditions as well as from complex fluids like whole human blood under high shear. Our findings may have far reaching implications, as they suggest that VEGF could be used to promote endothelialization of vascular grafts or neovascularization of implanted tissues by rare but continuously circulating EC. PMID:25771020

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

ERIC Educational Resources Information Center

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

2012-01-01

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…

Measuring Sense of Community: A Methodological Interpretation of the Factor Structure Debate

ERIC Educational Resources Information Center

Peterson, N. Andrew; Speer, Paul W.; Hughey, Joseph

2006-01-01

Instability in the factor structure of the Sense of Community Index (SCI) was tested as a methodological artifact. Confirmatory factor analyses, tested with two data sets, supported neither the proposed one-factor nor the four-factor (needs fulfillment, group membership, influence, and emotional connection) SCI. Results demonstrated that the SCI…

Simulation Analysis of Fluid-Structure Interaction of High Velocity Environment Influence on Aircraft Wing Materials under Different Mach Numbers.

PubMed

Zhang, Lijun; Sun, Changyan

2018-04-18

Aircraft service process is in a state of the composite load of pressure and temperature for a long period of time, which inevitably affects the inherent characteristics of some components in aircraft accordingly. The flow field of aircraft wing materials under different Mach numbers is simulated by Fluent in order to extract pressure and temperature on the wing in this paper. To determine the effect of coupling stress on the wing’s material and structural properties, the fluid-structure interaction (FSI) method is used in ANSYS-Workbench to calculate the stress that is caused by pressure and temperature. Simulation analysis results show that with the increase of Mach number, the pressure and temperature on the wing’s surface both increase exponentially and thermal stress that is caused by temperature will be the main factor in the coupled stress. When compared with three kinds of materials, titanium alloy, aluminum alloy, and Haynes alloy, carbon fiber composite material has better performance in service at high speed, and natural frequency under coupling pre-stressing will get smaller.

Simulation Analysis of Fluid-Structure Interaction of High Velocity Environment Influence on Aircraft Wing Materials under Different Mach Numbers

PubMed Central

Sun, Changyan

2018-01-01

Aircraft service process is in a state of the composite load of pressure and temperature for a long period of time, which inevitably affects the inherent characteristics of some components in aircraft accordingly. The flow field of aircraft wing materials under different Mach numbers is simulated by Fluent in order to extract pressure and temperature on the wing in this paper. To determine the effect of coupling stress on the wing’s material and structural properties, the fluid-structure interaction (FSI) method is used in ANSYS-Workbench to calculate the stress that is caused by pressure and temperature. Simulation analysis results show that with the increase of Mach number, the pressure and temperature on the wing’s surface both increase exponentially and thermal stress that is caused by temperature will be the main factor in the coupled stress. When compared with three kinds of materials, titanium alloy, aluminum alloy, and Haynes alloy, carbon fiber composite material has better performance in service at high speed, and natural frequency under coupling pre-stressing will get smaller. PMID:29670023

Examination of the factor structure of the Schizotypal Personality Questionnaire among British and Trinidadian adults.

PubMed

Barron, David; Swami, Viren; Towell, Tony; Hutchinson, Gerard; Morgan, Kevin D

2015-01-01

Much debate in schizotypal research has centred on the factor structure of the Schizotypal Personality Questionnaire (SPQ), with research variously showing higher-order dimensionality consisting of two to seven dimensions. In addition, cross-cultural support for the stability of those factors remains limited. Here, we examined the factor structure of the SPQ among British and Trinidadian adults. Participants from a White British subsample (n = 351) resident in the UK and from an African Caribbean subsample (n = 284) resident in Trinidad completed the SPQ. The higher-order factor structure of the SPQ was analysed through confirmatory factor analysis, followed by multiple-group analysis for the model of best fit. Between-group differences for sex and ethnicity were investigated using multivariate analysis of variance in relation to the higher-order domains. The model of best-fit was the four-factor structure, which demonstrated measurement invariance across groups. Additionally, these data had an adequate fit for two alternative models: (a) 3-factor and (b) modified 4-factor model. The British subsample had significantly higher scores across all domains than the Trinidadian group, and men scored significantly higher on the disorganised domain than women. The four-factor structure received confirmatory support and, importantly, support for use with populations varying in ethnicity and culture.

Aircraft passenger comfort experience: underlying factors and differentiation from discomfort.

PubMed

Ahmadpour, Naseem; Robert, Jean-Marc; Lindgaard, Gitte

2016-01-01

Previous studies defined passengers' comfort based on their concerns during the flight and a set of eight experiential factors such as 'peace of mind', 'physical wellbeing', 'pleasure', etc. One Objective of this paper was to determine whether the factors underlying the passengers' experience of comfort differ from those of discomfort. Another objective was to cross-validate those factors. In the first study, respondents provided written reports of flight comfort and discomfort experiences separately and gave ratings on the impact of the eight factors on each experience. Follow up interviews were also conducted. Significant difference was found between comfort and discomfort ratings for two factors of 'pleasure', denoted by one's concern for stimulation, ambience and exceeded expectations, and 'physical wellbeing' characterized in terms of bodily support and energy. However, there were no significant differences between the comfort and discomfort ratings on the other six factors. The evidence does not support the proposition that passenger comfort and discomfort are underline by different sets of factors. It is therefore suggested that the evaluation of overall passenger comfort experience, as a whole, employ one spectrum ranging from extreme comfort to discomfort. In study two, a pool of comfort descriptors was collected. Those that were less relevant to passenger comfort were eliminated in a number of steps. Factor analysis was used to classify the remaining descriptors, using respondents' ratings on their potential impact on passenger comfort. Seven factors corresponded to the pre-determined passenger comfort factors from previous research, validating those with an exception of 'proxemics' (concerning one's privacy and control over their situation) but it was argued that this is due to the nature of the factor itself, which is context dependent and generally perceived unconsciously. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Bed structure (frond bleaching, density and biomass) of the red alga Gelidium corneum under different irradiance levels

NASA Astrophysics Data System (ADS)

Quintano, E.; Díez, I.; Muguerza, N.; Figueroa, F. L.; Gorostiaga, J. M.

2017-12-01

In recent decades a decline in the foundation species Gelidium corneum (Hudson) J. V. Lamouroux has been detected along the Basque coast (northern Spain). This decline has been attributed to several factors, but recent studies have found a relationship between high irradiance and the biochemical and physiological stress of G. corneum. Since physiological responses to changes in light occur well before variations in morphology, the present study seeks to use a size-class demographic approach to investigate whether shallow subtidal populations of G. corneum off the Basque coast show different frond bleaching, density and biomass under different irradiance conditions. The results revealed that the bleaching incidence and cover were positively related to irradiance, whereas biomass was negatively related. The effect of the irradiance level on frond density was found to vary with size-class, i.e. fronds up to 15 cm showed greater densities under high light conditions (126.6 to 262.2 W m- 2) whereas the number of larger fronds (> 20 cm) per unit area was lower. In conclusion, the results of the present study suggest that irradiance might be a key factor for controlling along-shore bleaching, frond density and biomass in G. corneum. Further research should be carried out on the physiology of this canopy species in relation to its bed structure and on the interaction of irradiance and other abiotic (nutrients, temperature, wave energy) and biotic factors (grazing pressure).

Factor structure of the Japanese Interpersonal Competence Scale.

PubMed

Matsudaira, Tomomi; Fukuhara, Taihei; Kitamura, Toshinori

2008-04-01

Assessing social competence is important for clinical and preventive interventions of depression. The aim of the present paper was to examine the factor structure of the Japanese Interpersonal Competence Scale (JICS). Exploratory and confirmatory factor analysis was performed on the survey responses of 730 participants. Simultaneous multigroup analyses were conducted to confirm factor stability across psychological health status and sex differences. Two factors, which represent Perceptive Ability and Self-Restraint, were confirmed to show a moderate correlation. Perceptive Ability involves a more cognitive aspect of social competence, while Self-Restraint involves a more behavioral aspect, both of which are considered to reflect the emotion-based relating style specific to the Japanese people: indulgent dependence (amae) and harmony (wa). In addition, Self-Restraint may be linked to social functioning. Both constructs may confound a respondent's perceived confidence. Despite its shortcomings, the JICS is a unique measure of social competence in the Japanese cultural context.

Factors affecting strategic plan implementation using interpretive structural modeling (ISM).

PubMed

Bahadori, Mohammadkarim; Teymourzadeh, Ehsan; Tajik, Hamidreza; Ravangard, Ramin; Raadabadi, Mehdi; Hosseini, Seyed Mojtaba

2018-06-11

Purpose Strategic planning is the best tool for managers seeking an informed presence and participation in the market without surrendering to changes. Strategic planning enables managers to achieve their organizational goals and objectives. Hospital goals, such as improving service quality and increasing patient satisfaction cannot be achieved if agreed strategies are not implemented. The purpose of this paper is to investigate the factors affecting strategic plan implementation in one teaching hospital using interpretive structural modeling (ISM). Design/methodology/approach The authors used a descriptive study involving experts and senior managers; 16 were selected as the study sample using a purposive sampling method. Data were collected using a questionnaire designed and prepared based on previous studies. Data were analyzed using ISM. Findings Five main factors affected strategic plan implementation. Although all five variables and factors are top level, "senior manager awareness and participation in the strategic planning process" and "creating and maintaining team participation in the strategic planning process" had maximum drive power. "Organizational structure effects on the strategic planning process" and "Organizational culture effects on the strategic planning process" had maximum dependence power. Practical implications Identifying factors affecting strategic plan implementation is a basis for healthcare quality improvement by analyzing the relationship among factors and overcoming the barriers. Originality/value The authors used ISM to analyze the relationship between factors affecting strategic plan implementation.

Structural Rearrangement of Energetic Materials under an External Electric Field: A Case Study of Nitromethane.

PubMed

Liu, Yingzhe; Ma, Yiding; Yu, Tao; Lai, Weipeng; Guo, Wangjun; Ge, Zhongxue; Ma, Zhinan

2018-03-01

As a significant stimulus, the external electric field (EEF) can change the decomposition mechanism and energy release of energetic materials (EMs). Hence, understanding the response of EMs to an EEF is greatly meaningful for their safe usage. Herein, the structural arrangement, a crucial factor in the impact sensitivity and detonation performance of EMs, under the EEF ranging from 0.0 to 0.5 V/Å was investigated via molecular dynamics simulation. Nitromethane (NM) was taken as a case study due to the simple structure. The simulation results show that there exists a critical EEF strength between 0.2 and 0.3 V/Å, which can induce the transition of NM molecules from relatively disordered distribution to solidlike ordered and compacted arrangement with a large density. In this ordered structure, NM dipoles are aligned in a head-to-tail pattern parallel to the EEF direction because of the favored dipole-dipole interactions and weak C-H···O hydrogen bonds. As the EEF strength is enhanced, the potential energy and cohesive energy density of the NM system gradually decrease and increase, respectively, indicative of high thermodynamics stability of ordered arrangement. The results reported here also shed light on the potential of the EEF to induce the nucleation and crystallization to explore new polymorphs of EMs.

Factor Structure and Internal Validity of the Functional Movement Screen in Adults.

PubMed

Koehle, Michael S; Saffer, Boaz Y; Sinnen, Nadine M; MacInnis, Martin J

2016-02-01

The factor structure and internal consistency of the Functional Movement Screen (FMS) have not been examined in a general healthcare population. Replicating the factor structure of the FMS is important because it illustrates the interdependence between each of the subtests, enabling the strength and conditioning professional to better interpret and act on an individual's FMS score. Anthropometric data and FMS scores were collected from 1,113 clients of a multidisciplinary healthcare clinic in Vancouver, BC The mean (SD) ages were 53.4 (11.1) for men (n = 656) and 49.3 (12.3) for women (n = 457). The mean FMS Summary Score was 13.7 (2.9) and was significantly negatively correlated with both age (r = -0.25; p < 0.001) and body mass index (r = -0.37; p < 0.001). The internal consistency of the FMS scale, which was assessed with both ordinal and Cronbach's alpha, was 0.73 and 0.64, respectively. Polychoric correlations between individual movements ranged from 0.03 to 0.59. Exploratory and confirmatory factor analyses (CFA) revealed that the FMS showed 2 main factors, a basic movement factor (shoulder mobility and active straight leg raise) and a complex movement factor (squat, hurdle step, inline lunge, and the trunk stability push-up). Rotary stability loaded onto both factors in the CFA, and its exclusion from the model had little effect. The findings of this study broadly replicated the intended factor structure of the FMS, as the individual movements aligned well with the intended factors.

Depression Anxiety Stress Scales (DASS-21): Factor Structure in Traumatic Brain Injury Rehabilitation.

PubMed

Randall, Diane; Thomas, Matt; Whiting, Diane; McGrath, Andrew

To confirm the construct validity of the Depression Anxiety Stress Scales-21 (DASS-21) by investigating the fit of published factor structures in a sample of adults with moderate to severe traumatic brain injury (posttraumatic amnesia > 24 hours). Archival data from 504 patient records at the Brain Injury Rehabilitation Unit at Liverpool Hospital, Australia. Participants were aged between 16 and 71 years and were engaged in a specialist rehabilitation program. The DASS-21. Two of the 6 models had adequate fit using structural equation modeling. The data best fit Henry and Crawford's quadripartite model, which comprised a Depression, Anxiety and Stress factor, as well as a General Distress factor. The data also adequately fit Lovibond and Lovibond's original 3-factor model, and the internal consistencies of each factor were very good (α = 0.82-0.90). This study confirms the structure and construct validity of the DASS-21 and provides support for its use as a screening tool in traumatic brain injury rehabilitation.

The structure of the nucleon: Elastic electromagnetic form factors

DOE PAGES

Punjabi, V.; Perdrisat, C. F.; Jones, M. K.; ...

2015-07-10

Precise proton and neutron form factor measurements at Jefferson Lab, using spin observables, have recently made a significant contribution to the unraveling of the internal structure of the nucleon. Accurate experimental measurements of the nucleon form factors are a test-bed for understanding how the nucleon's static properties and dynamical behavior emerge from QCD, the theory of the strong interactions between quarks. There has been enormous theoretical progress, since the publication of the Jefferson Lab proton form factor ratio data, aiming at reevaluating the picture of the nucleon. We will review the experimental and theoretical developments in this field and discussmore » the outlook for the future.« less

Acquired high titre factor VIII inhibitor with underlying polyarteritis nodosa.

PubMed

Snowden, J A; Hutchings, M; Spearing, R; Patton, W N

1997-05-01

We here present the case of a 70-year-old woman referred to our unit for investigation of bleeding. Investigations confirmed a high titre acquired Factor VIII inhibitor. In association there was relapse of systemic illness associated with anti-neutrophil cytoplasmic antibodies (atypical pattern) for which she had been treated five years previously. Immunosuppression was attempted, but it failed to have an impact both on the inhibitor titre and on the underlying disorder. The patient died from multi-organ failure and massive chest hemorrhage. Post-mortem showed necrotizing vasculitis of medium sized vessels at several sites, including the kidney, consistent with a diagnosis of polyarteritis nodosa. Although it is well recognised that Factor VIII inhibitors are found in conjunction with autoimmune disorders, this case is significant in that it is the first associated with histologically proven polyarteritis nodosa type vasculitis. The case illustrates the difficulties in the investigation and management of patients with acquired high titre Factor VIII inhibitors.

Local structure and structural signature underlying properties in metallic glasses and supercooled liquids

NASA Astrophysics Data System (ADS)

Ding, Jun

Metallic glasses (MGs), discovered five decades ago as a newcomer in the family of glasses, are of current interest because of their unique structures and properties. There are also many fundamental materials science issues that remain unresolved for metallic glasses, as well as their predecessor above glass transition temperature, the supercooled liquids. In particular, it is a major challenge to characterize the local structure and unveil the structure-property relationship for these amorphous materials. This thesis presents a systematic study of the local structure of metallic glasses as well as supercooled liquids via classical and ab initio molecular dynamics simulations. Three typical MG models are chosen as representative candidate, Cu64 Zr36, Pd82Si18 and Mg65Cu 25Y10 systems, while the former is dominant with full icosahedra short-range order and the prism-type short-range order dominate for latter two. Furthermore, we move to unravel the underlying structural signature among several properties in metallic glasses. Firstly, the temperature dependence of specific heat and liquid fragility between Cu-Zr and Mg-Cu-Y (also Pd-Si) in supercooled liquids are quite distinct: gradual versus fast evolution of specific heat and viscosity/relaxation time with undercooling. Their local structural ordering are found to relate with the temperature dependence of specific heat and relaxation time. Then elastic heterogeneity has been studied to correlate with local structure in Cu-Zr MGs. Specifically, this part covers how the degree of elastic deformation correlates with the internal structure at the atomic level, how to quantitatively evaluate the local solidity/liquidity in MGs and how the network of interpenetrating connection of icosahedra determine the corresponding shear modulus. Finally, we have illustrated the structure signature of quasi-localized low-frequency vibrational normal modes, which resides the intriguing vibrational properties in MGs. Specifically, the

Scientific literacy: Factor structure and gender differences

NASA Astrophysics Data System (ADS)

Manhart, James Joseph

The purpose of this study was to investigate the factor structure of scientific literacy and to document any gender differences with respect to each factor. Participants included 1139 students (574 females, 565 males) in grades 9 through 12 who were taking a science class at one of four Midwestern high schools. Based on National Science Education Standards, a 100 item multiple-choice test was constructed to assess scientific literacy. Confirmatory factor analysis of item parcels suggested a three factor model was the best way to explain the data resulting from the administration of this test. The factors were labeled constructs of science, abilities necessary to do scientific inquiry, and social aspects of science. Gender differences with respect to these factors were examined using analysis of variance procedures. Because differential enrollment in science classes could cause gender differences in grades 11 and 12, parallel analyses were conducted on the grades 9 and 10 subsample and the grades 11 and 12 subsample. However, the results of the two analyses were similar. The most consistent gender difference observed was that females performed better than males on the social aspects of science factor. Males tended to perform better than females on the constructs of science factor, although no consistent gender difference was noted for items dealing with life science. With respect to the abilities necessary to do scientific inquiry factor, females tended to perform better than males in grades 9 and 10, while no consistent gender difference was observed in grades 11 and 12. Gender differences were also examined using the Mantel-Haenszel procedure to flag individual items that functioned differently for females and males of the same ability. Twelve items were flagged for grades 9 and 10 (8 in favor of females, 4 in favor of males). Fourteen items were flagged for grades 11 and 12 (7 in favor of females, 7 in favor of males). All of the flagged items exhibited only

Latent Factor Structure of DSM-5 Posttraumatic Stress Disorder

PubMed Central

Gentes, Emily; Dennis, Paul A.; Kimbrel, Nathan A.; Kirby, Angela C.; Hair, Lauren P.; Beckham, Jean C.; Calhoun, Patrick S.

2015-01-01

The current study examined the latent factor structure of posttraumatic stress disorder (PTSD) based on DSM-5 criteria in a sample of participants (N = 374) recruited for studies on trauma and health. Confirmatory factor analyses (CFA) were used to compare the fit of the previous 3-factor DSM-IV model of PTSD to the 4-factor model specified in DSM-5 as well as to a competing 4-factor “dysphoria” model (Simms, Watson, & Doebbeling, 2002) and a 5-factor (Elhai et al., 2011) model of PTSD. Results indicated that the Elhai 5-factor model (re-experiencing, active avoidance, emotional numbing, dysphoric arousal, anxious arousal) provided the best fit to the data, although substantial support was demonstrated for the DSM-5 4-factor model. Low factor loadings were noted for two of the symptoms in the DSM-5 model (psychogenic amnesia and reckless/self-destructive behavior), which raises questions regarding the adequacy of fit of these symptoms with other core features of the disorder. Overall, the findings from the present research suggest the DSM-5 model of PTSD is a significant improvement over the previous DSM-IV model of PTSD. PMID:26366290

Parametric and Non-Parametric Vibration-Based Structural Identification Under Earthquake Excitation

NASA Astrophysics Data System (ADS)

Pentaris, Fragkiskos P.; Fouskitakis, George N.

2014-05-01

The problem of modal identification in civil structures is of crucial importance, and thus has been receiving increasing attention in recent years. Vibration-based methods are quite promising as they are capable of identifying the structure's global characteristics, they are relatively easy to implement and they tend to be time effective and less expensive than most alternatives [1]. This paper focuses on the off-line structural/modal identification of civil (concrete) structures subjected to low-level earthquake excitations, under which, they remain within their linear operating regime. Earthquakes and their details are recorded and provided by the seismological network of Crete [2], which 'monitors' the broad region of south Hellenic arc, an active seismic region which functions as a natural laboratory for earthquake engineering of this kind. A sufficient number of seismic events are analyzed in order to reveal the modal characteristics of the structures under study, that consist of the two concrete buildings of the School of Applied Sciences, Technological Education Institute of Crete, located in Chania, Crete, Hellas. Both buildings are equipped with high-sensitivity and accuracy seismographs - providing acceleration measurements - established at the basement (structure's foundation) presently considered as the ground's acceleration (excitation) and at all levels (ground floor, 1st floor, 2nd floor and terrace). Further details regarding the instrumentation setup and data acquisition may be found in [3]. The present study invokes stochastic, both non-parametric (frequency-based) and parametric methods for structural/modal identification (natural frequencies and/or damping ratios). Non-parametric methods include Welch-based spectrum and Frequency response Function (FrF) estimation, while parametric methods, include AutoRegressive (AR), AutoRegressive with eXogeneous input (ARX) and Autoregressive Moving-Average with eXogeneous input (ARMAX) models[4, 5

The Swedish WAIS-R Factor Structure and Cognitive Profiles for Adults with Dyslexia.

ERIC Educational Resources Information Center

Alm, Jan; Kaufman, Alan S.

2002-01-01

Factor analysis of the Swedish version of the Wechsler Adult Intelligence Scale-Revised on 88 adults with dyslexia showed a three-factor structure: a verbal comprehension (VC) factor, a perceptual organization (PO) factor, and a freedom from distractibility (FD) factor. The PO factor had the highest scores and the FD the lowest. (Contains…

Factor structure and longitudinal measurement invariance of PHQ-9 for specialist mental health care patients with persistent major depressive disorder: Exploratory Structural Equation Modelling.

PubMed

Guo, Boliang; Kaylor-Hughes, Catherine; Garland, Anne; Nixon, Neil; Sweeney, Tim; Simpson, Sandra; Dalgleish, Tim; Ramana, Rajini; Yang, Min; Morriss, Richard

2017-09-01

The Patient Health Questionnaire-9 (PHQ-9) is a widely used instrument for measuring levels of depression in patients in clinical practice and academic research; its factor structure has been investigated in various samples, with limited evidence of measurement equivalence/invariance (ME/I) but not in patients with more severe depression of long duration. This study aims to explore the factor structure of the PHQ-9 and the ME/I between treatment groups over time for these patients. 187 secondary care patients with persistent major depressive disorder (PMDD) were recruited to a randomised controlled trial (RCT) with allocation to either a specialist depression team arm or a general mental health arm; their PHQ-9 score was measured at baseline, 3, 6, 9 and 12 months. Exploratory Structural Equational Modelling (ESEM) was performed to examine the factor structure for this specific patient group. ME/I between treatment arm at and across follow-up time were further explored by means of multiple-group ESEM approach using the best-fitted factor structure. A two-factor structure was evidenced (somatic and affective factor). This two-factor structure had strong factorial invariance between the treatment groups at and across follow up times. Participants were largely white British in a RCT with 40% attrition potentially limiting the study's generalisability. Not all two-factor modelling criteria were met at every time-point. PHQ-9 has a two-factor structure for PMDD patients, with strong measurement invariance between treatment groups at and across follow-up time, demonstrating its validity for RCTs and prospective longitudinal studies in chronic moderate to severe depression. Copyright © 2017. Published by Elsevier B.V.

A Confirmatory Factor Analysis of the Structure of Abbreviated Math Anxiety Scale

PubMed Central

Farrokhi, Farahman

2011-01-01

Objective The aim of this study is to explore the confirmatory factor analysis results of the Persian adaptation of Abbreviated Math Anxiety Scale (AMAS), proposed by Hopko, Mahadevan, Bare & Hunt. Method The validity and reliability assessments of the scale were performed on 298 college students chosen randomly from Tabriz University in Iran. The confirmatory factor analysis (CFA) was carried out to determine the factor structures of the Persian version of AMAS. Results As expected, the two-factor solution provided a better fit to the data than a single factor. Moreover, multi-group analyses showed that this two-factor structure was invariant across sex. Hence, AMAS provides an equally valid measure for use among college students. Conclusions Brief AMAS demonstrates adequate reliability and validity. The AMAS scores can be used to compare symptoms of math anxiety between male and female students. The study both expands and adds support to the existing body of math anxiety literature. PMID:22952521

Current-voltage characteristics of the semiconductor nanowires under the metal-semiconductor-metal structure

NASA Astrophysics Data System (ADS)

Wen, Jing; Zhang, Xitian; Gao, Hong; Wang, Mingjiao

2013-12-01

We present a method to calculate the I-V characteristics of semiconductor nanowires under the metal-semiconductor-metal (MSM) structure. The carrier concentration as an important parameter is introduced into the expression of the current. The subband structure of the nanowire has been considered for associating it with the position of the Fermi level and circumventing the uncertainties of the contact areas in the contacts. The tunneling and thermionic emission currents in the two Schottky barriers at the two metal-semiconductor contacts are discussed. We find that the two barriers have different influences on the I-V characteristics of the MSM structure, one of which under the forward bias plays the role of threshold voltage if its barrier height is large and the applied voltage is small, and the other under the reverse bias controls the shapes of I-V curves. Our calculations show that the shapes of the I-V curves for the MSM structure are mainly determined by the barrier heights of the contacts and the carrier concentration. The nearly identical I-V characteristics can be obtained by using different values of the barrier heights and carrier concentration, which means that the contact type conversion can be ascribed not only to the changes of the barrier heights but also that of the carrier concentration. We also discuss the mechanisms of the ohmic-Schottky conversions and clarify the ambiguity in the literature. The possibility about the variation of the carrier concentration under the applied fields has been confirmed by experimental results.

Factor structure of the functional movement screen in marine officer candidates.

PubMed

Kazman, Josh B; Galecki, Jeffrey M; Lisman, Peter; Deuster, Patricia A; OʼConnor, Francis G

2014-03-01

Functional movement screening (FMS) is a musculoskeletal assessment that is intended to fill a gap between preparticipation examinations and performance tests. Functional movement screening consists of 7 standardized movements involving multiple muscle groups that are rated 0-3 during performance; scores are combined into a final score, which is intended to predict injury risk. This use of a sum-score in this manner assumes that the items are unidimensional and scores are internally consistent, which are measures of internal reliability. Despite research into the FMS' predictive value and interrater reliability, research has not assessed its psychometric properties. The present study is a standard psychometric analysis of the FMS and is the first to assess the internal consistency and factor structure of the FMS, using Cronbach's alpha and exploratory factor analysis (EFA). Using a cohort of 877 male and 57 female Marine officer candidates who performed the FMS, EFA of polychoric correlations with varimax rotation was conducted to explore the structure of the FMS. Tests were repeated on the original scores, which integrated feelings of pain during movement (0-3), and then on scores discounting the pain instruction and based only on the performance (1-3), to determine whether pain ratings affected the factor structure. The average FMS score was 16.7 ± 1.8. Cronbach's alpha was 0.39. Exploratory factor analysis availed 2 components accounting for 21 and 17% and consisting of separate individual movements (shoulder mobility and deep squat, respectively). Analysis on scores discounting pain showed similar results. The factor structures were not interpretable, and the low Cronbach's alpha suggests a lack of internal consistency in FMS sum scores. Results do not offer support for validity of the FMS sum score as a unidimensional construct. In the absence of additional psychometric research, caution is warranted when using the FMS sum score.

Factor structure of the Liebowitz Social Anxiety Scale for Children and Adolescents.

PubMed

Storch, Eric A; Masia-Warner, Carrie; Heidgerken, Amanda D; Fisher, Paige H; Pincus, Donna B; Liebowitz, Michael R

2006-01-01

The purpose of this study was to evaluate the factor structure of the Liebowitz Social Anxiety Scale for Children and Adolescents (LSAS-CA). The LSAS-CA was administered to 225 children and adolescents as a component of various clinical studies. In addition, other measures of psychopathology and impairment were administered to a subgroup of the sample. Confirmatory factor analyses of the social interaction and performance subscales for the anxiety and avoidance ratings yielded poor fit indices. Exploratory factor analysis supported a two-factor solution with a higher order factor for the LSAS-CA anxiety and avoidance ratings. Based on item content, factors were named Social and School Performance. The internal consistency of the factors was high and the convergent and divergent validity was supported vis-à-vis correlations with measures of depression and social anxiety, and clinician ratings of impairment and functioning. Findings suggest that the anxiety and avoidance ratings are best explained by a two-factor solution that measures social anxiety and avoidance in social and school performance interactions. This factor structure appears to be a reliable and valid framework for assessing childhood social phobia.

Construction of protocellular structures under simulated primitive earth conditions

NASA Astrophysics Data System (ADS)

Yanagawa, Hiroshi; Ogawa, Yoko; Kojima, Kiyotsugu; Ito, Masahiko

1988-09-01

We have developed experimental approaches for the construction of protocellular structures under simulated primitive earth conditions and studied their formation and characteristics. Three types of envelopes; protein envelopes, lipid envelopes, and lipid-protein envelopes are considered as candidates for protocellular structures. Simple protein envelopes and lipid envelopes are presumed to have originated at an early stage of chemical evolution, interaction mutually and then evolved into more complex envelopes composed of both lipids and proteins. Three kinds of protein envelopes were constructedin situ from amino acids under simulated primitive earth conditions such as a fresh water tide pool, a warm sea, and a submarine hydrothermal vent. One protein envelope was formed from a mixture of amino acid amides at 80 °C using multiple hydration-dehydration cycles. Marigranules, protein envelope structures, were produced from mixtures of glycine and acidic, basic and aromatic amino acids at 105 °C in a modified sea medium enriched with essential transition elements. Thermostable microspheres were also formed from a mixture of glycine, alanine, valine, and aspartic acid at 250 °C and above. The microspheres did not form at lower temperatures and consist of silicates and peptide-like polymers containing imide bonds and amino acid residues enriched in valine. Amphiphilic proteins with molecular weights of 2000 were necessary for the formation of the protein envelopes. Stable lipid envelopes were formed from different dialkyl phospholipids and fatty acids. Large, stable, lipid-protein envelopes were formed from egg lecithin and the solubilized marigranules. Polycations such as polylysine and polyhistidine, or basic proteins such as lysozyme and cytochromec also stabilized lipid-protein envelopes.

Ethnic identity: Factor structure and measurement invariance across ethnic groups.

PubMed

Feitosa, Jennifer; Lacerenza, Christina N; Joseph, Dana L; Salas, Eduardo

2017-09-01

Considering a historically diversified (and growing) population in the United States, one's ethnic identification is often an important psychological-as well as social and political-construct because it can serve as a hindrance to interpersonal interaction. Despite the importance of ethnic identity in psychological research, the most widely developed ethnic identity measurement tool, the Multigroup Ethnic Identity Measure (MEIM; Phinney, 1992), lacks consensus regarding its psychometric properties. The purpose of this article is to identify the factor structure of this measure and identify whether it exhibits measurement equivalence/invariance (ME/I) across ethnicities. The current findings offer several contributions to the state of the literature. First, our data suggests a two-factor model, including affirmation/commitment and exploration factors, is the most appropriate structure when considering fit and parsimony indices via confirmatory factor analysis. Second, configural and metric measurement equivalence was found across Caucasian and non-Caucasian participants. Interestingly, partial scalar invariance was established when comparing Caucasians with the minority groups with the exception of the Hispanic subgroup, which exhibited no scalar invariance. Third, differences in ethnic identity factor means were found, especially across Caucasians and African Americans. In conclusion, the use of the two-factor model of the MEIM is recommended, and results suggest that the MEIM is an appropriate measure of ethnic identity in most ethnic groups. Limitations and future research are also discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Perceived Parental Attitudes of Gender Expansiveness: Development and Preliminary Factor Structure of a Self-Report Youth Questionnaire

PubMed Central

Hidalgo, Marco A.; Chen, Diane; Garofalo, Robert; Forbes, Catherine

2017-01-01

Abstract Purpose: Parental acceptance of gender identity/expression in lesbian, gay, bisexual, transgender, and queer/questioning (LGBTQ+) youth moderates the effects of minority stress on mental health outcomes. Given this association, mental health clinicians of gender-expansive adolescents often assess the degree to which these youth perceive their parents/primary caregivers as accepting or nonaffirming of their gender identity and expression. While existing measures may reliably assess youth's perceptions of general family support, no known tool aids in the assessment an adolescent's perceived parental support related to adolescent gender-expansive experiences. Methods: To provide both clinicians and researchers with an empirically derived tool, the current study used factor analysis to explore an underlying factor structure of a brief questionnaire developed by subject-matter experts and pertaining to multiple aspects of perceived parental support in gender-expansive adolescents and young adults. Respondents were gender-expansive adolescents and young adults seeking care in an interdisciplinary gender-health clinic within a pediatric academic medical center in the Midwestern United States. Results: Exploratory factor analysis resulted in a 14-item questionnaire comprised of two subscales assessing perceived parental nonaffirmation and perceived parental acceptance. Internal consistency and construct validity results provided support for this new questionnaire. Conclusion: This study provides preliminary evidence of the factor structure, reliability and validity of the Parental Attitudes of Gender Expansiveness Scale for Youth (PAGES-Y). These findings demonstrate both the clinical and research utility of the PAGES-Y, a tool that can yield a more nuanced understanding of family-related risk and protective factors in gender-expansive adolescents. PMID:29159312

Perceived Parental Attitudes of Gender Expansiveness: Development and Preliminary Factor Structure of a Self-Report Youth Questionnaire.

PubMed

Hidalgo, Marco A; Chen, Diane; Garofalo, Robert; Forbes, Catherine

2017-01-01

Purpose: Parental acceptance of gender identity/expression in lesbian, gay, bisexual, transgender, and queer/questioning (LGBTQ+) youth moderates the effects of minority stress on mental health outcomes. Given this association, mental health clinicians of gender-expansive adolescents often assess the degree to which these youth perceive their parents/primary caregivers as accepting or nonaffirming of their gender identity and expression. While existing measures may reliably assess youth's perceptions of general family support, no known tool aids in the assessment an adolescent's perceived parental support related to adolescent gender-expansive experiences. Methods: To provide both clinicians and researchers with an empirically derived tool, the current study used factor analysis to explore an underlying factor structure of a brief questionnaire developed by subject-matter experts and pertaining to multiple aspects of perceived parental support in gender-expansive adolescents and young adults. Respondents were gender-expansive adolescents and young adults seeking care in an interdisciplinary gender-health clinic within a pediatric academic medical center in the Midwestern United States. Results: Exploratory factor analysis resulted in a 14-item questionnaire comprised of two subscales assessing perceived parental nonaffirmation and perceived parental acceptance. Internal consistency and construct validity results provided support for this new questionnaire. Conclusion: This study provides preliminary evidence of the factor structure, reliability and validity of the Parental Attitudes of Gender Expansiveness Scale for Youth (PAGES-Y). These findings demonstrate both the clinical and research utility of the PAGES-Y, a tool that can yield a more nuanced understanding of family-related risk and protective factors in gender-expansive adolescents.

Perinatal Risk Factors Altering Regional Brain Structure in the Preterm Infant

ERIC Educational Resources Information Center

Thompson, Deanne K.; Warfield, Simon K.; Carlin, John B.; Pavlovic, Masa; Wang, Hong X.; Bear, Merilyn; Kean, Michael J.; Doyle, Lex W.; Egan, Gary F.; Inder, Terrie E.

2007-01-01

Neuroanatomical structure appears to be altered in preterm infants, but there has been little insight into the major perinatal risk factors associated with regional cerebral structural alterations. MR images were taken to quantitatively compare regional brain tissue volumes between term and preterm infants and to investigate associations between…

Factors Underlying the Relationship Between Parent and Child Grief.

PubMed

Cipriano, David J; Cipriano, Madeline R

2017-01-01

The death of a parent in a child's life is a significant risk factor for later mental and physical health problems. While much has been written about the surviving parent's functioning and its effects on their bereaved children, little work has been done to look into factors underlying this effect such as how the parent copes. The present study recruited 38 parent-child dyads from a community-based grief support center. Parent and child, independently, completed various measures of emotional functioning, including grief symptoms and coping such as social support and locus of control. The results indicated that parental coping did have an impact on children's grief symptoms. This represents a unique view of adaptation in bereaved children: Parental coping strategies can have an impact on the child, independent of the child's coping strategies. By focusing on parent coping, we have highlighted another possible pathway through which parental functioning affects children's grief.

Probabilistic Simulation of the Human Factor in Structural Reliability

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Singhal, Surendra N.

1994-01-01

The formal approach described herein computationally simulates the probable ranges of uncertainties for the human factor in probabilistic assessments of structural reliability. Human factors such as marital status, professional status, home life, job satisfaction, work load, and health are studied by using a multifactor interaction equation (MFIE) model to demonstrate the approach. Parametric studies in conjunction with judgment are used to select reasonable values for the participating factors (primitive variables). Subsequently performed probabilistic sensitivity studies assess the suitability of the MFIE as well as the validity of the whole approach. Results show that uncertainties range from 5 to 30 percent for the most optimistic case, assuming 100 percent for no error (perfect performance).

Probabilistic simulation of the human factor in structural reliability

NASA Astrophysics Data System (ADS)

Chamis, Christos C.; Singhal, Surendra N.

1994-09-01

The formal approach described herein computationally simulates the probable ranges of uncertainties for the human factor in probabilistic assessments of structural reliability. Human factors such as marital status, professional status, home life, job satisfaction, work load, and health are studied by using a multifactor interaction equation (MFIE) model to demonstrate the approach. Parametric studies in conjunction with judgment are used to select reasonable values for the participating factors (primitive variables). Subsequently performed probabilistic sensitivity studies assess the suitability of the MFIE as well as the validity of the whole approach. Results show that uncertainties range from 5 to 30 percent for the most optimistic case, assuming 100 percent for no error (perfect performance).

Structural Integrity of Proteins under Applied Bias during Solid-State Nanopore Translocation

NASA Astrophysics Data System (ADS)

Hasan, Mohammad R.; Khanzada, Raja Raheel; Mahmood, Mohammed A. I.; Ashfaq, Adnan; Iqbal, Samir M.

2015-03-01

The translocation behavior of proteins through solid-state nanopores can be used as a new way to detect and identify proteins. The ionic current through a nanopore that flows under applied bias gets perturbed when a biomolecule traverses the Nanopore. It is important for a protein detection scheme to know of any changes in the three-dimensional structure of the molecule during the process. Here we report the data on structural integrity of protein during translocation through nanopore under different applied biases. Nanoscale Molecular Dynamic was used to establish a framework to study the changes in protein structures as these travelled across the nanopore. The analysis revealed the contributions of structural changes of protein to its ionic current signature. As a model, thrombin protein crystalline structure was imported and positioned inside a 6 nm diameter pore in a 6 nm thick silicon nitride membrane. The protein was solvated in 1 M KCl at 295 K and the system was equilibrated for 20 ns to attain its minimum energy state. The simulation was performed at different electric fields from 0 to 1 kCal/(mol.Å.e). RMSD, radial distribution function, movement of the center of mass and velocity of the protein were calculated. The results showed linear increments in the velocity and perturbations in ionic current profile with increasing electric potential. Support Acknowledged from NSF through ECCS-1201878.

Review of parameters influencing the structural response of a submerged body under cavitation conditions

NASA Astrophysics Data System (ADS)

Escaler, X.; De La Torre, O.; Farhat, M.

2015-12-01

Submerged structures that operate under extreme flows are prone to suffer large scale cavitation attached to their surfaces. Under such conditions the added mass effects differ from the expected ones in pure liquids. Moreover, the existence of small gaps between the structure and surrounding bodies filled with fluid also influence the dynamic response. A series of experiments and numerical simulations have been carried out with a truncated NACA0009 hydrofoil mounted as a cantilever beam at the LMH-EPFL cavitation tunnel. The three first modes of vibration have been determined and analysed under various hydrodynamic conditions ranging from air and still water to partial cavitation and supercavitation. A remote nonintrusive excitation system with piezoelectric patches has been used for the experiments. The effects of the cavity properties and the lateral gap size on the natural frequencies and mode shapes have been determined. As a result, the significance of several parameters in the design of such structures is discussed.

Stability Study on Steel Structural Columns with Initial Blast Damage under High Temperatures

NASA Astrophysics Data System (ADS)

Baoxin, Qi; Yan, Shi; Li, Peng

2018-03-01

Blast may bring light-weight steel columns with initial damages, resulting in lowering its critical fire-resistance temperature whose reduced amplitude is relevant to the form and degree of the damages. Finite element analysis software ANSYS was used in the paper to analyze the issue of the fire-resistance temperature of the column with the blast damages, and the coupling method for heat and structure was applied during the simulation. The emphasis was laid on parametric factors of axial compression ratio, the form and the degree of the initial damages, as well as the confined condition at the ends of the columns. The numerical results showed that the fire-resistance temperature will lower as increasing of the axial compression ratio, the form and the degree of the initial damages and it will be also affected by the restraint conditions at the ends of the columns. The critical stress formula with initial bending damage under elevated temperature was set up under flexural small deformation condition, then the stability coefficient was determined and the method for evaluating the limit temperature of the column was put forward. The theoretical result was also compared with that of the finite element method (FEM). The results both showed that the stability capacity for the damaged columns was dramatically reduced as increasing the temperature and the initial damage level.

Use of a safety climate questionnaire in UK health care: factor structure, reliability and usability.

PubMed

Hutchinson, A; Cooper, K L; Dean, J E; McIntosh, A; Patterson, M; Stride, C B; Laurence, B E; Smith, C M

2006-10-01

To explore the factor structure, reliability, and potential usefulness of a patient safety climate questionnaire in UK health care. Four acute hospital trusts and nine primary care trusts in England. The questionnaire used was the 27 item Teamwork and Safety Climate Survey. Thirty three healthcare staff commented on the wording and relevance. The questionnaire was then sent to 3650 staff within the 13 NHS trusts, seeking to achieve at least 600 responses as the basis for the factor analysis. 1307 questionnaires were returned (36% response). Factor analyses and reliability analyses were carried out on 897 responses from staff involved in direct patient care, to explore how consistently the questions measured the underlying constructs of safety climate and teamwork. Some questionnaire items related to multiple factors or did not relate strongly to any factor. Five items were discarded. Two teamwork factors were derived from the remaining 11 teamwork items and three safety climate factors were derived from the remaining 11 safety items. Internal consistency reliabilities were satisfactory to good (Cronbach's alpha > or =0.69 for all five factors). This is one of the few studies to undertake a detailed evaluation of a patient safety climate questionnaire in UK health care and possibly the first to do so in primary as well as secondary care. The results indicate that a 22 item version of this safety climate questionnaire is useable as a research instrument in both settings, but also demonstrates a more general need for thorough validation of safety climate questionnaires before widespread usage.

Factor structure of the Wechsler Intelligence Scale for Children-Fifth Edition: Exploratory factor analyses with the 16 primary and secondary subtests.

PubMed

Canivez, Gary L; Watkins, Marley W; Dombrowski, Stefan C

2016-08-01

The factor structure of the 16 Primary and Secondary subtests of the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V; Wechsler, 2014a) standardization sample was examined with exploratory factor analytic methods (EFA) not included in the WISC-V Technical and Interpretive Manual (Wechsler, 2014b). Factor extraction criteria suggested 1 to 4 factors and results favored 4 first-order factors. When this structure was transformed with the Schmid and Leiman (1957) orthogonalization procedure, the hierarchical g-factor accounted for large portions of total and common variance while the 4 first-order factors accounted for small portions of total and common variance; rendering interpretation at the factor index level less appropriate. Although the publisher favored a 5-factor model where the Perceptual Reasoning factor was split into separate Visual Spatial and Fluid Reasoning dimensions, no evidence for 5 factors was found. It was concluded that the WISC-V provides strong measurement of general intelligence and clinical interpretation should be primarily, if not exclusively, at that level. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Calabi-Yau structures on categories of matrix factorizations

NASA Astrophysics Data System (ADS)

Shklyarov, Dmytro

2017-09-01

Using tools of complex geometry, we construct explicit proper Calabi-Yau structures, that is, non-degenerate cyclic cocycles on differential graded categories of matrix factorizations of regular functions with isolated critical points. The formulas involve the Kapustin-Li trace and its higher corrections. From the physics perspective, our result yields explicit 'off-shell' models for categories of topological D-branes in B-twisted Landau-Ginzburg models.

Personal Attitudes or Structural Factors? A Contextual Analysis of Breastfeeding Duration

ERIC Educational Resources Information Center

McKinley, Nita Mary; Hyde, Janet Shibley

2004-01-01

A personal attitudes model (i.e., infant feeding choices are based on personal attitudes primarily) and a structural factors model (i.e., feeding choices are shaped by the structural contexts of women's lives, as much as personal attitudes) of women's breastfeeding behavior were tested by surveying a longitudinal sample of 548 mostly European…

The Factor Structure of the Beck Depression Inventory-II: An Evaluation

ERIC Educational Resources Information Center

Vanheule, Stijn; Desmet, Mattias; Groenvynck, Hans; Rosseel, Yves; Fontaine, Johnny

2008-01-01

The Beck Depression Inventory-II (BDI-II) is a frequently used scale for measuring depressive severity. BDI-II data (404 clinical; 695 nonclinical adults) were analyzed by means of confirmatory factor analysis to test whether the factor structure model with a somatic-affective and cognitive component of depression, formulated by Beck and…

The Structure of Temperament in Preschoolers: A Two-Stage Factor Analytic Approach

PubMed Central

Dyson, Margaret W.; Olino, Thomas M.; Durbin, C. Emily; Goldsmith, H. Hill; Klein, Daniel N.

2012-01-01

The structure of temperament traits in young children has been the subject of extensive debate, with separate models proposing different trait dimensions. This research has relied almost exclusively on parent-report measures. The present study used an alternative approach, a laboratory observational measure, to explore the structure of temperament in preschoolers. A 2-stage factor analytic approach, exploratory factor analyses (n = 274) followed by confirmatory factor analyses (n = 276), was used. We retrieved an adequately fitting model that consisted of 5 dimensions: Sociability, Positive Affect/Interest, Dysphoria, Fear/Inhibition, and Constraint versus Impulsivity. This solution overlaps with, but is also distinct from, the major models derived from parent-report measures. PMID:21859196

Structural and Discriminant Validity of the Career Factors Inventory

ERIC Educational Resources Information Center

Dickinson, Josephine; Tokar, David M.

2004-01-01

Using a sample of 350 college students, this study examined the structural and discriminant validity of the Career Factors Inventory (CFI; Chartrand, Robbins, Morrill, & Boggs, 1990), a multidimensional measure of career indecision intended to be scored for two informational indecision components (Need for Career Information and Need for…

Spatial heterogeneity and risk factors for stunting among children under age five in Ethiopia: A Bayesian geo-statistical model.

PubMed

Hagos, Seifu; Hailemariam, Damen; WoldeHanna, Tasew; Lindtjørn, Bernt

2017-01-01

Understanding the spatial distribution of stunting and underlying factors operating at meso-scale is of paramount importance for intervention designing and implementations. Yet, little is known about the spatial distribution of stunting and some discrepancies are documented on the relative importance of reported risk factors. Therefore, the present study aims at exploring the spatial distribution of stunting at meso- (district) scale, and evaluates the effect of spatial dependency on the identification of risk factors and their relative contribution to the occurrence of stunting and severe stunting in a rural area of Ethiopia. A community based cross sectional study was conducted to measure the occurrence of stunting and severe stunting among children aged 0-59 months. Additionally, we collected relevant information on anthropometric measures, dietary habits, parent and child-related demographic and socio-economic status. Latitude and longitude of surveyed households were also recorded. Local Anselin Moran's I was calculated to investigate the spatial variation of stunting prevalence and identify potential local pockets (hotspots) of high prevalence. Finally, we employed a Bayesian geo-statistical model, which accounted for spatial dependency structure in the data, to identify potential risk factors for stunting in the study area. Overall, the prevalence of stunting and severe stunting in the district was 43.7% [95%CI: 40.9, 46.4] and 21.3% [95%CI: 19.5, 23.3] respectively. We identified statistically significant clusters of high prevalence of stunting (hotspots) in the eastern part of the district and clusters of low prevalence (cold spots) in the western. We found out that the inclusion of spatial structure of the data into the Bayesian model has shown to improve the fit for stunting model. The Bayesian geo-statistical model indicated that the risk of stunting increased as the child's age increased (OR 4.74; 95% Bayesian credible interval [BCI]:3.35-6.58) and

Who is on the primary care team? Professionals' perceptions of the conceptualization of teams and the underlying factors: a mixed-methods study.

PubMed

Doekhie, Kirti D; Buljac-Samardzic, Martina; Strating, Mathilde M H; Paauwe, Jaap

2017-12-28

Due to the growing prevalence of elderly patients with multi-morbidity living at home, there is an increasing need for primary care professionals from different disciplinary backgrounds to collaborate as primary care teams. However, it is unclear how primary care professionals conceptualize teams and what underlying factors influence their perception of being part of a team. Our research question is: What are primary care professionals' perceptions of teams and team membership among primary care disciplines and what factors influence their perceptions? We conducted a mixed-methods study in the Dutch primary care setting. First, a survey study of 152 professionals representing 12 primary care disciplines was conducted, focusing on their perceptions of which disciplines are part of the team and the degree of relational coordination between professionals from different disciplinary backgrounds. Subsequently, we conducted semi-structured interviews with 32 professionals representing 5 primary care disciplines to gain a deeper understanding of the underlying factors influencing their perceptions and the (mis)alignment between these perceptions. Misalignments were found between perceptions regarding which disciplines are members of the team and the relational coordination between disciplines. For example, general practitioners were viewed as part of the team by helping assistants, (district) nurses, occupational therapists and geriatric specialized practice nurses, whereas the general practitioners themselves only considered geriatric specialized practice nurses to be part of their team. Professionals perceive multidisciplinary primary care teams as having multiple inner and outer layers. Three factors influence their perception of being part of a team and acting accordingly: a) knowing the people you work with, b) the necessity for knowledge exchange and c) sharing a holistic view of caregiving. Research and practice should take into account the misalignment between

Synchronous scattering and diffraction from gold nanotextured surfaces with structure factors

NASA Astrophysics Data System (ADS)

Gu, Min-Jhong; Lee, Ming-Tsang; Huang, Chien-Hsun; Wu, Chi-Chun; Chen, Yu-Bin

2018-05-01

Synchronous scattering and diffraction were demonstrated using reflectance from gold nanotextured surfaces at oblique (θi = 15° and 60°) incidence of wavelength λ = 405 nm. Two samples of unique auto-correlation functions were cost-effectively fabricated. Multiple structure factors of their profiles were confirmed with Fourier expansions. Bi-directional reflectance function (BRDF) from these samples provided experimental proofs. On the other hand, standard deviation of height and unique auto-correlation function of each sample were used to generate surfaces numerically. Comparing their BRDF with those of totally random rough surfaces further suggested that structure factors in profile could reduce specular reflection more than totally random roughness.

Factors associated with chronic diseases among the elderly receiving treatment under the Family Health Strategy.

PubMed

Pimenta, Fernanda Batista; Pinho, Lucinéia; Silveira, Marise Fagundes; Botelho, Ana Cristina de Carvalho

2015-08-01

The profile of a sample population of elderly receiving treatment under the Family Health Strategy in the municipality of Teófilo Otoni, State of Minas Gerais, Brazil, is described, and the factors associated with diseases prevalence examined. Using simple random sampling, 385 elderly were interviewed using Form A and Elderly Form from the Primary Health Care Information System. The majority of the sample (83.1%) self-reported at least one disease, 69.9% had hypertension, and 17.7% had diabetes. Poisson regression analysis showed that the main factors associated with hypertension and other diseases were being non-white, having a low level of education, medication use, dental prosthesis use, and lack of a private health plan. The prevalence of diabetes was greater among women and individuals who depended on other people to live. It can be concluded that this sample population of elderly has a generally low socioeconomic status and are more susceptible to developing diseases, particularly hypertension. Diabetes should be controlled although had relatively low prevalence. It is suggested investments in structuring the health system network to provide adequate care for the elderly and in training health professionals to play an effective role in improving the quality of life of the elderly in Brazil.

Effect of structural factors on mechanical properties of the magnesium alloy Ma2-1 under quasi-static and high strain rate deformation conditions

NASA Astrophysics Data System (ADS)

Garkushin, G. V.; Razorenov, S. V.; Krasnoveikin, V. A.; Kozulin, A. A.; Skripnyak, V. A.

2015-02-01

The elastic limit and tensile strength of deformed magnesium alloys Ma2-1 with different structures and textures were measured with the aim of finding a correlation between the spectrum of defects in the material and the resistance to deformation and fracture under quasi-static and dynamic loading conditions. The studies were performed using specimens in the as-received state after high-temperature annealing and specimens subjected to equal-channel angular pressing at a temperature of 250°C. The anisotropy of strength characteristics of the material after shock compression with respect to the direction of rolling of the original alloy was investigated. It was shown that, in contrast to the quasi-static loading conditions, under the shock wave loading conditions, the elastic limit and tensile strength of the magnesium alloy Ma2-1 after equal-channel angular pressing decrease as compared to the specimens in the as-received state.

Using structured additive regression models to estimate risk factors of malaria: analysis of 2010 Malawi malaria indicator survey data.

PubMed

Chirombo, James; Lowe, Rachel; Kazembe, Lawrence

2014-01-01

After years of implementing Roll Back Malaria (RBM) interventions, the changing landscape of malaria in terms of risk factors and spatial pattern has not been fully investigated. This paper uses the 2010 malaria indicator survey data to investigate if known malaria risk factors remain relevant after many years of interventions. We adopted a structured additive logistic regression model that allowed for spatial correlation, to more realistically estimate malaria risk factors. Our model included child and household level covariates, as well as climatic and environmental factors. Continuous variables were modelled by assuming second order random walk priors, while spatial correlation was specified as a Markov random field prior, with fixed effects assigned diffuse priors. Inference was fully Bayesian resulting in an under five malaria risk map for Malawi. Malaria risk increased with increasing age of the child. With respect to socio-economic factors, the greater the household wealth, the lower the malaria prevalence. A general decline in malaria risk was observed as altitude increased. Minimum temperatures and average total rainfall in the three months preceding the survey did not show a strong association with disease risk. The structured additive regression model offered a flexible extension to standard regression models by enabling simultaneous modelling of possible nonlinear effects of continuous covariates, spatial correlation and heterogeneity, while estimating usual fixed effects of categorical and continuous observed variables. Our results confirmed that malaria epidemiology is a complex interaction of biotic and abiotic factors, both at the individual, household and community level and that risk factors are still relevant many years after extensive implementation of RBM activities.

The underlying pathway structure of biochemical reaction networks

PubMed Central

Schilling, Christophe H.; Palsson, Bernhard O.

1998-01-01

Bioinformatics is yielding extensive, and in some cases complete, genetic and biochemical information about individual cell types and cellular processes, providing the composition of living cells and the molecular structure of its components. These components together perform integrated cellular functions that now need to be analyzed. In particular, the functional definition of biochemical pathways and their role in the context of the whole cell is lacking. In this study, we show how the mass balance constraints that govern the function of biochemical reaction networks lead to the translation of this problem into the realm of linear algebra. The functional capabilities of biochemical reaction networks, and thus the choices that cells can make, are reflected in the null space of their stoichiometric matrix. The null space is spanned by a finite number of basis vectors. We present an algorithm for the synthesis of a set of basis vectors for spanning the null space of the stoichiometric matrix, in which these basis vectors represent the underlying biochemical pathways that are fundamental to the corresponding biochemical reaction network. In other words, all possible flux distributions achievable by a defined set of biochemical reactions are represented by a linear combination of these basis pathways. These basis pathways thus represent the underlying pathway structure of the defined biochemical reaction network. This development is significant from a fundamental and conceptual standpoint because it yields a holistic definition of biochemical pathways in contrast to definitions that have arisen from the historical development of our knowledge about biochemical processes. Additionally, this new conceptual framework will be important in defining, characterizing, and studying biochemical pathways from the rapidly growing information on cellular function. PMID:9539712

Ab initio simulations of the dynamic ion structure factor of warm dense lithium

DOE PAGES

Witte, B. B. L.; Shihab, M.; Glenzer, S. H.; ...

2017-04-06

Here, we present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible targetmore » inhomogeneities on x-ray scattering spectra.« less

Ab initio simulations of the dynamic ion structure factor of warm dense lithium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witte, B. B. L.; Shihab, M.; Glenzer, S. H.

Here, we present molecular dynamics simulations based on finite-temperature density functional theory that determine self-consistently the dynamic ion structure factor and the electronic form factor in lithium. Our comprehensive data set allows for the calculation of the dispersion relation for collective excitations, the calculation of the sound velocity, and the determination of the ion feature from the total electronic form factor and the ion structure factor. The results are compared with available experimental x-ray and neutron scattering data. Good agreement is found for both the liquid metal and warm dense matter domain. Finally, we study the impact of possible targetmore » inhomogeneities on x-ray scattering spectra.« less

Similarity between community structures of different online social networks and its impact on underlying community detection

NASA Astrophysics Data System (ADS)

Fan, W.; Yeung, K. H.

2015-03-01

As social networking services are popular, many people may register in more than one online social network. In this paper we study a set of users who have accounts of three online social networks: namely Foursquare, Facebook and Twitter. Community structure of this set of users may be reflected in these three online social networks. Therefore, high correlation between these reflections and the underlying community structure may be observed. In this work, community structures are detected in all three online social networks. Also, we investigate the similarity level of community structures across different networks. It is found that they show strong correlation with each other. The similarity between different networks may be helpful to find a community structure close to the underlying one. To verify this, we propose a method to increase the weights of some connections in networks. With this method, new networks are generated to assist community detection. By doing this, value of modularity can be improved and the new community structure match network's natural structure better. In this paper we also show that the detected community structures of online social networks are correlated with users' locations which are identified on Foursquare. This information may also be useful for underlying community detection.

Energy under-reporting in adults with mood disorders: prevalence and associated factors.

PubMed

Davison, Karen M

2013-09-01

Little is known about relationships of energy under-reporting in mental health populations. Using data from a sample of individuals with mood disorders (n = 97), demographic, food intake and body-related, psychological, lifestyle, and condition-specific factors were examined in relationship to energy under-reporting. More than two-thirds (70%) were considered under-reporters based on Goldberg's classifications. Differences were found between energy under-reporters and accurate reporters for diet quality, sex, body mass index (BMI), weight change after taking psychiatric medications, and for those taking mood stabilizers (all p's < 0.05). Regression analyses indicated there was lower prevalence of under-reporting as diet quality improved, if individuals experienced weight change after taking psychiatric medication, or were females (p < 0.05). The prevalence of under-reporting was more than 1.3 times in those taking mood stabilizers versus those not taking this psychiatric medication [Prevalence ratio (PR) = 1.30, 95% CI 1.01-1.66, p < 0.05]. Further research of under-reporting in mental health populations will enable targeted approaches to improve accuracy of diet reporting and inferences made about nutrition and mental health.

Factor Structure of the Quality of Life Scale for Mental Disorders in Patients With Schizophrenia.

PubMed

Chiu, En-Chi; Lee, Shu-Chun

2018-06-01

The Quality of Life for Mental Disorders (QOLMD) scale was designed to measure health-related quality of life (HRQOL) in patients with mental illness, especially schizophrenia. The QOLMD contains 45 items, which are divided into eight domains. However, the factor structure of the QOLMD has not been evaluated, which restricts the interpretations of the results of this scale. The purpose of this study was to evaluate the factor structures (i.e., unidimensionality, eight-factor structure, and second-order model) of the QOLMD in patients with schizophrenia. Two hundred thirty-eight outpatients with schizophrenia participated. We first conducted confirmatory factor analysis to evaluate the unidimensionality of each domain. After the unidimensionality of the eight individual domains was supported, we examined the eight-factor structure and second-order model. The results of unidimensionality showed sufficient model fit in all of the domains with the exception of the autonomy domain. A good model fit was confirmed for the autonomy domain after deleting two of the original items. The eight-factor structure for the 43-item QOLMD showed an acceptable model fit, although the second-order model showed poor model fit. Our results supported the unidimensionality and eight-factor structure of the 43-item QOLMD. The sum score for each of the domains may be used to reflect its domain-specific function. We recommend using the 43-item QOLMD to capture the multiple domains of HRQOL. However, the second-order model showed an unsatisfactory model fit. Furthermore, caution is advised when interpreting overall HRQOL using the total score for the eight domains.

Airborne Transducer Integrity under Operational Environment for Structural Health Monitoring

PubMed Central

Salmanpour, Mohammad Saleh; Sharif Khodaei, Zahra; Aliabadi, Mohammad Hossein

2016-01-01

This paper investigates the robustness of permanently mounted transducers used in airborne structural health monitoring systems, when exposed to the operational environment. Typical airliners operate in a range of conditions, hence, structural health monitoring (SHM) transducer robustness and integrity must be demonstrated for these environments. A set of extreme temperature, altitude and vibration environment test profiles are developed using the existing Radio Technical Commission for Aeronautics (RTCA)/DO-160 test methods. Commercially available transducers and manufactured versions bonded to carbon fibre reinforced polymer (CFRP) composite materials are tested. It was found that the DuraAct transducer is robust to environmental conditions tested, while the other transducer types degrade under the same conditions. PMID:27973450

A combined model of human erythropoiesis and granulopoiesis under growth factor and chemotherapy treatment

PubMed Central

2014-01-01

Background Haematotoxicity of conventional chemotherapies often results in delays of treatment or reduction of chemotherapy dose. To ameliorate these side-effects, patients are routinely treated with blood transfusions or haematopoietic growth factors such as erythropoietin (EPO) or granulocyte colony-stimulating factor (G-CSF). For the latter ones, pharmaceutical derivatives are available, which differ in absorption kinetics, pharmacokinetic and -dynamic properties. Due to the complex interaction of cytotoxic effects of chemotherapy and the stimulating effects of different growth factor derivatives, optimal treatment is a non-trivial task. In the past, we developed mathematical models of thrombopoiesis, granulopoiesis and erythropoiesis under chemotherapy and growth-factor applications which can be used to perform clinically relevant predictions regarding the feasibility of chemotherapy schedules and cytopenia prophylaxis with haematopoietic growth factors. However, interactions of lineages and growth-factors were ignored so far. Results To close this gap, we constructed a hybrid model of human granulopoiesis and erythropoiesis under conventional chemotherapy, G-CSF and EPO applications. This was achieved by combining our single lineage models of human erythropoiesis and granulopoiesis with a common stem cell model. G-CSF effects on erythropoiesis were also implemented. Pharmacodynamic models are based on ordinary differential equations describing proliferation and maturation of haematopoietic cells. The system is regulated by feedback loops partly mediated by endogenous and exogenous EPO and G-CSF. Chemotherapy is modelled by depletion of cells. Unknown model parameters were determined by fitting the model predictions to time series data of blood counts and cytokine profiles. Data were extracted from literature or received from cooperating clinical study groups. Our model explains dynamics of mature blood cells and cytokines after growth-factor applications in

Structural and vibrational properties of solid nitromethane under high pressure by density functional theory.

PubMed

Liu, Hong; Zhao, Jijun; Wei, Dongqing; Gong, Zizheng

2006-03-28

The structural, vibrational, and electronic properties of solid nitromethane under hydrostatic pressure of up to 20 GPa have been studied using density functional theory. The changes of cell volume, the lattice constants, and the molecular geometry of solid nitromethane under hydrostatic loading are examined, and the bulk modulus B0 and its pressure derivative B0' are fitted from the volume-pressure relation. Our theoretical results are compared with available experiments. The change of electron band gap of nitromethane under high pressure is also discussed. Based on the optimized crystal structures, the vibrational frequencies for the internal and lattice modes of the nitromethane crystal at ambient and high pressures are computed, and the pressure-induced frequency shifts of these modes are discussed.

Ordered quasi-two-dimensional structure of nanoparticles in semiflexible ring polymer brushes under compression

NASA Astrophysics Data System (ADS)

Hua, Yunfeng; Deng, Zhenyu; Jiang, Yangwei; Zhang, Linxi

2017-06-01

Molecular dynamics simulations of a coarse-grained bead-spring model of ring polymer brushes under compression are presented. Flexible polymer brushes are always disordered during compression, whereas semiflexible polymer brushes tend to be ordered under sufficiently strong compression. Further, the polymer monomer density of the semiflexible polymer brush is very high near the brush surface, inducing a peak value of the free energy near the surface. Therefore, when nanoparticles are compressed in semiflexible ring polymer brushes, they tend to exhibit a closely packed single-layer structure between the brush surface and the impenetrable wall, and a quasi-two-dimensional ordered structure near the brush surface is formed under strong compression. These findings provide a new approach to designing responsive applications.

Handwriting Performance and Underlying Factors in Children with Attention Deficit Hyperactivity Disorder

ERIC Educational Resources Information Center

Shen, I-Hsuan; Lee, Tsai-Yun; Chen, Chia-Ling

2012-01-01

Preliminary evidence suggests that handwriting difficulties are common to children with Attention Deficit Hyperactivity Disorder (ADHD). However, the nature of the task-specific impairments is needed to be clarified. The aim of this study was to describe handwriting capacity in ADHD children without DCD and identify underlying factors of…

The Experiences in Close Relationship Scale (ECR)-short form: reliability, validity, and factor structure.

PubMed

Wei, Meifen; Russell, Daniel W; Mallinckrodt, Brent; Vogel, David L

2007-04-01

We developed a 12-item, short form of the Experiences in Close Relationship Scale (ECR; Brennan, Clark, & Shaver, 1998) across 6 studies. In Study 1, we examined the reliability and factor structure of the measure. In Studies 2 and 3, we cross-validated the reliability, factor structure, and validity of the short form measure; whereas in Study 4, we examined test-retest reliability over a 1-month period. In Studies 5 and 6, we further assessed the reliability, factor structure, and validity of the short version of the ECR when administered as a stand-alone instrument. Confirmatory factor analyses indicated that 2 factors, labeled Anxiety and Avoidance, provided a good fit to the data after removing the influence of response sets. We found validity to be equivalent for the short and the original versions of the ECR across studies. Finally, the results were comparable when we embedded the short form within the original version of the ECR and when we administered it as a stand-alone measure.

Measurement invariance of the Illness Intrusiveness Ratings Scale's three-factor structure in men and women with cancer.

PubMed

Mah, Kenneth; Bezjak, Andrea; Loblaw, D Andrew; Gotowiec, Andrew; Devins, Gerald M

2011-02-01

Illness- and treatment-related disruptions to valued activities and interests (illness intrusiveness) are central to quality of life in chronic disease and are captured by three subscales of the Illness Intrusiveness Ratings Scale (IIRS): the Instrumental, Intimacy, and Relationships and Personal Development subscales. Using individual (CFA) and multisample confirmatory factor analyses (MSCFA), we evaluated measurement invariance of the IIRS's 3-factor structure in men and women with cancer. Men (n = 210) and women (n = 206) with 1 of 4 cancer diagnoses (gastrointestinal, head and neck, lymphoma, lung) recruited from outpatient clinics completed the IIRS. In the MSCFA, we applied an analysis of means and covariance structures approach to test increasingly stringent equality constraints on factor structure parameters to evaluate weak, strong, and strict measurement invariance of the 3-factor structure between men and women. Individual CFAs demonstrated fit of the hypothesized 3-factor structure for men and women, although more consistently for men. The 3-factor structure was superior to an alternative 1-factor structure. MSCFA results indicated that parameters of the 3-factor structure could be considered equivalent between the sexes up to the level of strong invariance. Strict invariance was not supported. Overall, IIRS scores can be interpreted similarly for men and women with cancer. Illness intrusiveness can be considered as important in the psychosocial adaptation of people with cancer as it is for people affected by other chronic conditions. (c) 2011 APA, all rights reserved

Research on the influencing factors of reverse logistics carbon footprint under sustainable development.

PubMed

Sun, Qiang

2017-10-01

With the concerns of ecological and circular economy along with sustainable development, reverse logistics has attracted the attention of enterprise. How to achieve sustainable development of reverse logistics has important practical significance of enhancing low carbon competitiveness. In this paper, the system boundary of reverse logistics carbon footprint is presented. Following the measurement of reverse logistics carbon footprint and reverse logistics carbon capacity is provided. The influencing factors of reverse logistics carbon footprint are classified into five parts such as intensity of reverse logistics, energy structure, energy efficiency, reverse logistics output, and product remanufacturing rate. The quantitative research methodology using ADF test, Johansen co-integration test, and impulse response is utilized to interpret the relationship between reverse logistics carbon footprint and the influencing factors more accurately. This research finds that energy efficiency, energy structure, and product remanufacturing rate are more capable of inhibiting reverse logistics carbon footprint. The statistical approaches will help practitioners in this field to structure their reverse logistics activities and also help academics in developing better decision models to reduce reverse logistics carbon footprint.

Factor Structure of the Behavior Flexibility Rating Scale (BFRS)

ERIC Educational Resources Information Center

Pituch, Keenan A.; Green, Vanessa A.; Sigafoos, Jeff; Itchon, Jonathan; O'Reilly, Mark; Lancioni, Giulio E.; Didden, Robert

2007-01-01

The Behavior Flexibility Rating Scale (BFRS) is designed to assess insistence on sameness or lack of behavioral flexibility, which is often associated with autism and other developmental disabilities. This study was designed to assess the factor structure of this scale for a sample of 968 individuals with autism, Asperger's syndrome, and Down…

Factor structure of the autonomy preference index in people with severe mental illness.

PubMed

Bonfils, Kelsey A; Adams, Erin L; Mueser, Kim T; Wright-Berryman, Jennifer L; Salyers, Michelle P

2015-08-30

People vary in the amount of control they want to exercise over decisions about their healthcare. Given the importance of patient-centered care, accurate measurement of these autonomy preferences is critical. This study aimed to assess the factor structure of the Autonomy Preference Index (API), used widely in general healthcare, in individuals with severe mental illness. Data came from two studies of people with severe mental illness (N=293) who were receiving mental health and/or primary care/integrated care services. Autonomy preferences were assessed with the API regarding both psychiatric and primary care services. Confirmatory factor analysis was used to evaluate fit of the hypothesized two-factor structure of the API (decision-making autonomy and information-seeking autonomy). Results indicated the hypothesized structure for the API did not adequately fit the data for either psychiatric or primary care services. Three problematic items were dropped, resulting in adequate fit for both types of treatment. These results suggest that with relatively minor modifications the API has an acceptable factor structure when asking people with severe mental illness about their preferences to be involved in decision-making. The modified API has clinical and research utility for this population in the burgeoning field of autonomy in patient-centered healthcare. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Contributions to the Underlying Bivariate Normal Method for Factor Analyzing Ordinal Data

ERIC Educational Resources Information Center

Xi, Nuo; Browne, Michael W.

2014-01-01

A promising "underlying bivariate normal" approach was proposed by Jöreskog and Moustaki for use in the factor analysis of ordinal data. This was a limited information approach that involved the maximization of a composite likelihood function. Its advantage over full-information maximum likelihood was that very much less computation was…

The Factor Structure of the Aggression Questionnaire With Violent Offenders.

PubMed

Pettersen, Cathrine; Nunes, Kevin L; Cortoni, Franca

2018-05-01

The Buss-Perry Aggression Questionnaire (AQ) is a self-report measure of aggressiveness commonly employed in nonforensic and forensic settings and is included in violent offender pre- and posttreatment assessment batteries. The aim of the current study was to assess the fit of the four-factor model of the AQ with violent offenders ( N = 271), a population for which the factor structure of the English version of the AQ has not previously been examined. Confirmatory factor analyses did not yield support for the four-factor model of the original 29-item AQ. Acceptable fit was obtained with the 12-item short form, but careful examination of the relationships between the latent factors revealed that the four subscales of the AQ may not represent distinct aspects of aggressiveness. Our findings call into question whether the AQ optimally measures trait aggressiveness among violent offenders.

Factors Influencing Implementation of OHSAS 18001 in Indian Construction Organizations: Interpretive Structural Modeling Approach

PubMed Central

Rajaprasad, Sunku Venkata Siva; Chalapathi, Pasupulati Venkata

2015-01-01

Background Construction activity has made considerable breakthroughs in the past two decades on the back of increases in development activities, government policies, and public demand. At the same time, occupational health and safety issues have become a major concern to construction organizations. The unsatisfactory safety performance of the construction industry has always been highlighted since the safety management system is neglected area and not implemented systematically in Indian construction organizations. Due to a lack of enforcement of the applicable legislation, most of the construction organizations are forced to opt for the implementation of Occupational Health Safety Assessment Series (OHSAS) 18001 to improve safety performance. Methods In order to better understand factors influencing the implementation of OHSAS 18001, an interpretive structural modeling approach has been applied and the factors have been classified using matrice d'impacts croises-multiplication appliqué a un classement (MICMAC) analysis. The study proposes the underlying theoretical framework to identify factors and to help management of Indian construction organizations to understand the interaction among factors influencing in implementation of OHSAS 18001. Results Safety culture, continual improvement, morale of employees, and safety training have been identified as dependent variables. Safety performance, sustainable construction, and conducive working environment have been identified as linkage variables. Management commitment and safety policy have been identified as the driver variables. Conclusion Management commitment has the maximum driving power and the most influential factor is safety policy, which states clearly the commitment of top management towards occupational safety and health. PMID:26929828

An Exploratory Investigation of the Factor Structure of the Reynolds Intellectual Assessment Scales (RIAS)

ERIC Educational Resources Information Center

Dombrowski, Stefan C.; Watkins, Marley W.; Brogan, Michael J.

2009-01-01

This study investigated the factor structure of the Reynolds Intellectual Assessment Scales (RIAS) using rigorous exploratory factor analytic and factor extraction procedures. The results of this study indicate that the RIAS is a single factor test. Despite these results, higher order factor analysis using the Schmid-Leiman procedure indicates…

[Comparison of the factors influencing young adolescents' aggression according to family structure].

PubMed

Yun, Eun Kyoung; Shin, Sung Hee

2013-06-01

This cross-sectional study was done to compare factors influencing young adolescents' aggression according to family structure. Participants were 680 young adolescents aged 11 to 15 years (113 in single father families, 136 in single mother families, 49 in grandparent families, and 382 in both-parent families). All measures were self-administered. Data were analyzed using SPSS 18.0 program and factors affecting young adolescents' aggression were analyzed by stepwise multiple regression. Levels of young adolescents' aggression and all variables were significantly different among the four family structure groups. Factors influencing young adolescents' aggression were also different according to these 4 groups. For single father families, depression-anxiety and family hardiness significantly predicted the level of young adolescents' aggression (adjusted R square=.37, p<.001). For single mother families, depression-anxiety, gender, and friends' support significantly predicted the level of young adolescents' aggression (adjusted R square=.58, p<.001). For grandparent families, depression-anxiety and family support significantly predicted the level of young adolescents' aggression (adjusted R square=.58, p<.001). For both-parent families, depression-anxiety, family hardiness, and friends' support significantly predicted the level of young adolescents' aggression (adjusted R square=.48, p<.001). Nurses working with young adolescents should consider family structure-specific factors influencing aggression in this population.

Migration and HIV prevention programmes: linking structural factors, culture, and individual behaviour--an Israeli experience.

PubMed

Soskolne, Varda; Shtarkshall, Ronny A

2002-10-01

Migration is one of the structural factors associated with HIV infections, but the dynamic and complex role of migrant situations as determinants of HIV-related vulnerability is still a major issue for social science research. Moreover, interventions to address the specific structural and contextual factors inherent in this association are limited and many do not take into account the cultural components. This paper presents a multi-level framework for analysis of the links between migration and HIV. It includes the association of migration with structural macro factors-lower socio-economic status and limited power in the new society; intermediate structural factors-limited social capital and bi-directional interaction of cultural norms; and individual-level factors-stressors unique to the migration context, depleted psychosocial resources, loss of cultural beliefs and low use of health services. All these factors affect risky sexual behaviour and transmission of HIV. The paper utilises those elements of the framework that are relevant to the specific needs of immigrant populations from the former Soviet Union and from Ethiopia in Israel. We demonstrate their application to integrated, multi-level HIV prevention interventions and propose several special principles for development of migration-related HIV prevention programmes.

Fluid-structure interaction dynamic simulation of spring-loaded pressure relief valves under seismic wave

NASA Astrophysics Data System (ADS)

Lv, Dongwei; Zhang, Jian; Yu, Xinhai

2018-05-01

In this paper, a fluid-structure interaction dynamic simulation method of spring-loaded pressure relief valve was established. The dynamic performances of the fluid regions and the stress and strain of the structure regions were calculated at the same time by accurately setting up the contact pairs between the solid parts and the coupling surfaces between the fluid regions and the structure regions. A two way fluid-structure interaction dynamic simulation of a simplified pressure relief valve model was carried out. The influence of vertical sinusoidal seismic waves on the performance of the pressure relief valve was preliminarily investigated by loading sine waves. Under vertical seismic waves, the pressure relief valve will flutter, and the reseating pressure was affected by the amplitude and frequency of the seismic waves. This simulation method of the pressure relief valve under vertical seismic waves can provide effective means for investigating the seismic performances of the valves, and make up for the shortcomings of the experiment.

Review of International Research on Factors Underlying Teacher Absenteeism. REL 2015-087

ERIC Educational Resources Information Center

Lee, Mary; Goodman, Crystal; Dandapani, Nitara; Kekahio, Wendy

2015-01-01

Throughout the U.S.-affiliated Pacific Region, teacher absenteeism has posed a long-standing challenge. This report draws on research literature from international contexts and case studies to identify the underlying factors that may relate to teacher absenteeism. Resources included in this report were selected with a focus on non-U.S. Pacific…

A simple and accurate method for calculation of the structure factor of interacting charged spheres.

PubMed

Wu, Chu; Chan, Derek Y C; Tabor, Rico F

2014-07-15

Calculation of the structure factor of a system of interacting charged spheres based on the Ginoza solution of the Ornstein-Zernike equation has been developed and implemented on a stand-alone spreadsheet. This facilitates direct interactive numerical and graphical comparisons between experimental structure factors with the pioneering theoretical model of Hayter-Penfold that uses the Hansen-Hayter renormalisation correction. The method is used to fit example experimental structure factors obtained from the small-angle neutron scattering of a well-characterised charged micelle system, demonstrating that this implementation, available in the supplementary information, gives identical results to the Hayter-Penfold-Hansen approach for the structure factor, S(q) and provides direct access to the pair correlation function, g(r). Additionally, the intermediate calculations and outputs can be readily accessed and modified within the familiar spreadsheet environment, along with information on the normalisation procedure. Copyright © 2014 Elsevier Inc. All rights reserved.

Structure factors for tunneling ionization rates of molecules: General Hartree-Fock-based integral representation

NASA Astrophysics Data System (ADS)

Madsen, Lars Bojer; Jensen, Frank; Dnestryan, Andrey I.; Tolstikhin, Oleg I.

2017-07-01

In the leading-order approximation of the weak-field asymptotic theory (WFAT), the dependence of the tunneling ionization rate of a molecule in an electric field on its orientation with respect to the field is determined by the structure factor of the ionizing molecular orbital. The WFAT yields an expression for the structure factor in terms of a local property of the orbital in the asymptotic region. However, in general quantum chemistry approaches molecular orbitals are expanded in a Gaussian basis which does not reproduce their asymptotic behavior correctly. This hinders the application of the WFAT to polyatomic molecules, which are attracting increasing interest in strong-field physics. Recently, an integral-equation approach to the WFAT for tunneling ionization of one electron from an arbitrary potential has been developed. The structure factor is expressed in an integral form as a matrix element involving the ionizing orbital. The integral is not sensitive to the asymptotic behavior of the orbital, which resolves the difficulty mentioned above. Here, we extend the integral representation for the structure factor to many-electron systems treated within the Hartree-Fock method and show how it can be implemented on the basis of standard quantum chemistry software packages. We validate the methodology by considering noble-gas atoms and the CO molecule, for which accurate structure factors exist in the literature. We also present benchmark results for CO2 and for NH3 in the pyramidal and planar geometries.

Methylation of class I translation termination factors: structural and functional aspects.

PubMed

Graille, Marc; Figaro, Sabine; Kervestin, Stéphanie; Buckingham, Richard H; Liger, Dominique; Heurgué-Hamard, Valérie

2012-07-01

During protein synthesis, release of polypeptide from the ribosome occurs when an in frame termination codon is encountered. Contrary to sense codons, which are decoded by tRNAs, stop codons present in the A-site are recognized by proteins named class I release factors, leading to the release of newly synthesized proteins. Structures of these factors bound to termination ribosomal complexes have recently been obtained, and lead to a better understanding of stop codon recognition and its coordination with peptidyl-tRNA hydrolysis in bacteria. Release factors contain a universally conserved GGQ motif which interacts with the peptidyl-transferase centre to allow peptide release. The Gln side chain from this motif is methylated, a feature conserved from bacteria to man, suggesting an important biological role. However, methylation is catalysed by completely unrelated enzymes. The function of this motif and its post-translational modification will be discussed in the context of recent structural and functional studies. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Simple methods of exploiting the underlying structure of rule-based systems

NASA Technical Reports Server (NTRS)

Hendler, James

1986-01-01

Much recent work in the field of expert systems research has aimed at exploiting the underlying structures of the rule base for reasons of analysis. Such techniques as Petri-nets and GAGs have been proposed as representational structures that will allow complete analysis. Much has been made of proving isomorphisms between the rule bases and the mechanisms, and in examining the theoretical power of this analysis. In this paper we describe some early work in a new system which has much simpler (and thus, one hopes, more easily achieved) aims and less formality. The technique being examined is a very simple one: OPS5 programs are analyzed in a purely syntactic way and a FSA description is generated. In this paper we describe the technique and some user interface tools which exploit this structure.

Structural basis of gene regulation by the Grainyhead/CP2 transcription factor family

PubMed Central

Ming, Qianqian; Roske, Yvette; Schuetz, Anja; Walentin, Katharina; Ibraimi, Ibraim; Schmidt-Ott, Kai M

2018-01-01

Abstract Grainyhead (Grh)/CP2 transcription factors are highly conserved in multicellular organisms as key regulators of epithelial differentiation, organ development and skin barrier formation. In addition, they have been implicated as being tumor suppressors in a variety of human cancers. Despite their physiological importance, little is known about their structure and DNA binding mode. Here, we report the first structural study of mammalian Grh/CP2 factors. Crystal structures of the DNA-binding domains of grainyhead-like (Grhl) 1 and Grhl2 reveal a closely similar conformation with immunoglobulin-like core. Both share a common fold with the tumor suppressor p53, but differ in important structural features. The Grhl1 DNA-binding domain binds duplex DNA containing the consensus recognition element in a dimeric arrangement, supporting parsimonious target-sequence selection through two conserved arginine residues. We elucidate the molecular basis of a cancer-related mutation in Grhl1 involving one of these arginines, which completely abrogates DNA binding in biochemical assays and transcriptional activation of a reporter gene in a human cell line. Thus, our studies establish the structural basis of DNA target-site recognition by Grh transcription factors and reveal how tumor-associated mutations inactivate Grhl proteins. They may serve as points of departure for the structure-based development of Grh/CP2 inhibitors for therapeutic applications. PMID:29309642

Feelings about culture scales: development, factor structure, reliability, and validity.

PubMed

Maffini, Cara S; Wong, Y Joel

2015-04-01

Although measures of cultural identity, values, and behavior exist in the multicultural psychological literature, there is currently no measure that explicitly assesses ethnic minority individuals' positive and negative affect toward culture. Therefore, we developed 2 new measures called the Feelings About Culture Scale--Ethnic Culture and Feelings About Culture Scale--Mainstream American Culture and tested their psychometric properties. In 6 studies, we piloted the measures, conducted factor analyses to clarify their factor structure, and examined reliability and validity. The factor structure revealed 2 dimensions reflecting positive and negative affect for each measure. Results provided evidence for convergent, discriminant, criterion-related, and incremental validity as well as the reliability of the scales. The Feelings About Culture Scales are the first known measures to examine both positive and negative affect toward an individual's ethnic culture and mainstream American culture. The focus on affect captures dimensions of psychological experiences that differ from cognitive and behavioral constructs often used to measure cultural orientation. These measures can serve as a valuable contribution to both research and counseling by providing insight into the nuanced affective experiences ethnic minority individuals have toward culture. (c) 2015 APA, all rights reserved).

Structural basis for signal recognition and transduction by platelet-activating-factor receptor.

PubMed

Cao, Can; Tan, Qiuxiang; Xu, Chanjuan; He, Lingli; Yang, Linlin; Zhou, Ye; Zhou, Yiwei; Qiao, Anna; Lu, Minmin; Yi, Cuiying; Han, Gye Won; Wang, Xianping; Li, Xuemei; Yang, Huaiyu; Rao, Zihe; Jiang, Hualiang; Zhao, Yongfang; Liu, Jianfeng; Stevens, Raymond C; Zhao, Qiang; Zhang, Xuejun C; Wu, Beili

2018-06-01

Platelet-activating-factor receptor (PAFR) responds to platelet-activating factor (PAF), a phospholipid mediator of cell-to-cell communication that exhibits diverse physiological effects. PAFR is considered an important drug target for treating asthma, inflammation and cardiovascular diseases. Here we report crystal structures of human PAFR in complex with the antagonist SR 27417 and the inverse agonist ABT-491 at 2.8-Å and 2.9-Å resolution, respectively. The structures, supported by molecular docking of PAF, provide insights into the signal-recognition mechanisms of PAFR. The PAFR-SR 27417 structure reveals an unusual conformation showing that the intracellular tips of helices II and IV shift outward by 13 Å and 4 Å, respectively, and helix VIII adopts an inward conformation. The PAFR structures, combined with single-molecule FRET and cell-based functional assays, suggest that the conformational change in the helical bundle is ligand dependent and plays a critical role in PAFR activation, thus greatly extending knowledge about signaling by G-protein-coupled receptors.

Manifestation of the shape-memory effect in polyetherurethane cellular plastics, fabric composites, and sandwich structures under microgravity

NASA Astrophysics Data System (ADS)

Babaevskii, P. G.; Kozlov, N. A.; Agapov, I. G.; Reznichenko, G. M.; Churilo, N. V.; Churilo, I. V.

2016-09-01

The results of experiments that were performed to test the feasibility of creating sandwich structures (consisting of thin-layer sheaths of polymer composites and a cellular polymer core) with the shapememory effect as models of the transformable components of space structures have been given. The data obtained indicate that samples of sandwich structures under microgravity conditions on board the International Space Station have recovered their shape to almost the same degree as under terrestrial conditions, which makes it possible to recommend them for creating components of transformable space structures on their basis.

g-Factor of heavy ions: a new access to the fine structure constant.

PubMed

Shabaev, V M; Glazov, D A; Oreshkina, N S; Volotka, A V; Plunien, G; Kluge, H-J; Quint, W

2006-06-30

A possibility for a determination of the fine structure constant in experiments on the bound-electron g-factor is examined. It is found that studying a specific difference of the g-factors of B- and H-like ions of the same spinless isotope in the Pb region to the currently accessible experimental accuracy of 7 x 10(-10) would lead to a determination of the fine structure constant to an accuracy which is better than that of the currently accepted value. Further improvements of the experimental and theoretical accuracy could provide a value of the fine structure constant which is several times more precise than the currently accepted one.

Factor structure and psychometric properties of the Body Appreciation Scale among adults in Hong Kong.

PubMed

Ng, Siu-Kuen; Barron, David; Swami, Viren

2015-03-01

Previous research has suggested that the factor structure of Body Appreciation Scale (BAS), a widely-used measure of positive body image, may not be cross-culturally equivalent. Here, we used confirmatory factor analysis to evaluate the conceptual equivalence of a Chinese (Cantonese) translation of the BAS among women (n=1319) and men (n=1084) in Hong Kong. Results showed that neither the one-dimensional nor proposed two-dimensional factor structures had adequate fit. Instead, a modified two-dimensional structure, which retained 9 of the 13 BAS items in two factors, had the best fit. However, only one of these factors, reflective of General Body Appreciation, had adequate internal consistency. This factor also had good patterns of construct validity, as indicated through significant correlations with participant body mass index, self-esteem, and (among women) actual-ideal weight discrepancy. The present results suggest that there may be cultural differences in the concept and experience of body appreciation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Probabilistic analysis of a materially nonlinear structure

NASA Technical Reports Server (NTRS)

Millwater, H. R.; Wu, Y.-T.; Fossum, A. F.

1990-01-01

A probabilistic finite element program is used to perform probabilistic analysis of a materially nonlinear structure. The program used in this study is NESSUS (Numerical Evaluation of Stochastic Structure Under Stress), under development at Southwest Research Institute. The cumulative distribution function (CDF) of the radial stress of a thick-walled cylinder under internal pressure is computed and compared with the analytical solution. In addition, sensitivity factors showing the relative importance of the input random variables are calculated. Significant plasticity is present in this problem and has a pronounced effect on the probabilistic results. The random input variables are the material yield stress and internal pressure with Weibull and normal distributions, respectively. The results verify the ability of NESSUS to compute the CDF and sensitivity factors of a materially nonlinear structure. In addition, the ability of the Advanced Mean Value (AMV) procedure to assess the probabilistic behavior of structures which exhibit a highly nonlinear response is shown. Thus, the AMV procedure can be applied with confidence to other structures which exhibit nonlinear behavior.

Stability assessment of structures under earthquake hazard through GRID technology

NASA Astrophysics Data System (ADS)

Prieto Castrillo, F.; Boton Fernandez, M.

2009-04-01

This work presents a GRID framework to estimate the vulnerability of structures under earthquake hazard. The tool has been designed to cover the needs of a typical earthquake engineering stability analysis; preparation of input data (pre-processing), response computation and stability analysis (post-processing). In order to validate the application over GRID, a simplified model of structure under artificially generated earthquake records has been implemented. To achieve this goal, the proposed scheme exploits the GRID technology and its main advantages (parallel intensive computing, huge storage capacity and collaboration analysis among institutions) through intensive interaction among the GRID elements (Computing Element, Storage Element, LHC File Catalogue, federated database etc.) The dynamical model is described by a set of ordinary differential equations (ODE's) and by a set of parameters. Both elements, along with the integration engine, are encapsulated into Java classes. With this high level design, subsequent improvements/changes of the model can be addressed with little effort. In the procedure, an earthquake record database is prepared and stored (pre-processing) in the GRID Storage Element (SE). The Metadata of these records is also stored in the GRID federated database. This Metadata contains both relevant information about the earthquake (as it is usual in a seismic repository) and also the Logical File Name (LFN) of the record for its later retrieval. Then, from the available set of accelerograms in the SE, the user can specify a range of earthquake parameters to carry out a dynamic analysis. This way, a GRID job is created for each selected accelerogram in the database. At the GRID Computing Element (CE), displacements are then obtained by numerical integration of the ODE's over time. The resulting response for that configuration is stored in the GRID Storage Element (SE) and the maximum structure displacement is computed. Then, the corresponding

HIV research productivity and structural factors associated with HIV research output in European Union countries: a bibliometric analysis.

PubMed

Uusküla, A; Toompere, K; Laisaar, K T; Rosenthal, M; Pürjer, M L; Knellwolf, A; Läärä, E; Des Jarlais, D C

2015-02-03

To assess HIV/AIDS research productivity in the 27 countries of the European Union (EU), and the structural level factors associated with levels of HIV/AIDS research productivity. A bibliometric analysis was conducted with systematic search methods used to locate HIV/AIDS research publications (period of 1 January 2002 to 31 December 2011; search databases: MEDLINE (Ovid, PubMed), EMBASE, ISI-Thomson Web of Science; no language restrictions). The publication rate (number of HIV/AIDS research publications per million population in 10 years) and the rate of articles published in HIV/AIDS journals and selected journals with moderate to very high (IF ≥3) 5-year impact factors were used as markers for HIV research productivity. A negative binomial regression model was fitted to assess the impact of structural level factors (sociodemographic, health, HIV prevalence and research/development indicators) associated with the variation in HIV research productivity. The total numbers of HIV/AIDS research publications in 2002-2011 by country ranged from 7 to 9128 (median 319). The median publication rate (per million population in 10 years) was 45 (range 5-150) for all publications. Across all countries, 16% of the HIV/AIDS research was published in HIV/AIDS journals and 7% in selected journals with IF ≥3. Indicators describing economic (gross domestic product), demographic (size of the population) and epidemiological (HIV prevalence) conditions as well as overall scientific activity (total research output) in a country were positively associated with HIV research productivity. HIV research productivity varies noticeably across EU countries, and this variation is associated with recognisable structural factors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Estimation of the Invariance of Factor Structures Across Sex and Race with Implications for Hypothesis Testing

ERIC Educational Resources Information Center

Katzenmeyer, W. G.; Stenner, A. Jackson

1977-01-01

The problem of demonstrating invariance of factor structures across criterion groups is addressed. Procedures are outlined which combine the replication of factor structures across sex-race groups with use of the coefficient of invariance to demonstrate the level of invariance associated with factors identified in a self concept measure.…

Using Structured Additive Regression Models to Estimate Risk Factors of Malaria: Analysis of 2010 Malawi Malaria Indicator Survey Data

PubMed Central

Chirombo, James; Lowe, Rachel; Kazembe, Lawrence

2014-01-01

Background After years of implementing Roll Back Malaria (RBM) interventions, the changing landscape of malaria in terms of risk factors and spatial pattern has not been fully investigated. This paper uses the 2010 malaria indicator survey data to investigate if known malaria risk factors remain relevant after many years of interventions. Methods We adopted a structured additive logistic regression model that allowed for spatial correlation, to more realistically estimate malaria risk factors. Our model included child and household level covariates, as well as climatic and environmental factors. Continuous variables were modelled by assuming second order random walk priors, while spatial correlation was specified as a Markov random field prior, with fixed effects assigned diffuse priors. Inference was fully Bayesian resulting in an under five malaria risk map for Malawi. Results Malaria risk increased with increasing age of the child. With respect to socio-economic factors, the greater the household wealth, the lower the malaria prevalence. A general decline in malaria risk was observed as altitude increased. Minimum temperatures and average total rainfall in the three months preceding the survey did not show a strong association with disease risk. Conclusions The structured additive regression model offered a flexible extension to standard regression models by enabling simultaneous modelling of possible nonlinear effects of continuous covariates, spatial correlation and heterogeneity, while estimating usual fixed effects of categorical and continuous observed variables. Our results confirmed that malaria epidemiology is a complex interaction of biotic and abiotic factors, both at the individual, household and community level and that risk factors are still relevant many years after extensive implementation of RBM activities. PMID:24991915

Factors Affecting Soil Microbial Community Structure in Tomato Cropping Systems

USDA-ARS?s Scientific Manuscript database

Soil and rhizosphere microbial communities in agroecosystems may be affected by soil, climate, plant species, and management. We identified some of the most important factors controlling microbial biomass and community structure in an agroecosystem utilizing tomato plants with the following nine tre...

The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents

PubMed Central

McMillin, Carl R.; Saito, Hidehiko; Ratnoff, Oscar D.; Walton, Alan G.

1974-01-01

Hageman factor (factor XII) is activated by exposure to surfaces such as glass or by solutions of certain compounds, notably ellagic acid. Changes in the structure of Hageman factor accompanying activation have been examined in this study by circular dichroism spectroscopy. The spectrum of unactivated Hageman factor in aqueous solutions suggests that its conformation is mainly aperiodic. Various perturbants altered the conformation of Hageman factor in differing ways, demonstrating the sensitivity of Hageman factor to its environment. After activation of Hageman factor with solutions of ellagic acid, a negative trough appeared in the region of the circular dichroism spectrum commonly assigned to tyrosine residues, along with other minor changes in the peptide spectral region. Some of these changes are similar to changes that occurred upon partial neutralization of the basic residues at alkali pH. Activation of Hageman factor by adsorption to quartz surfaces (in an aqueous environment) also produced changes similar to those in the ellagic acid-activated Hageman factor, including the negative ellipticity in the tyrosine region. These observations suggest that the activation process may be related to a change in status of some of the basic amino acid residues, coupled with a specific change in the environment of some tyrosine residues. The importance of these changes during the activation process remains to be determined. The sensitivity of Hageman factor to its environment is consistent with the view that the initiation of clotting by exposure of plasma to appropriate agents is brought about by alterations in the conformation of Hageman factor that occur in the apparent absence of Fletcher factor or other recognized clotting factors. Images PMID:4373492

Atomic study of effects of crystal structure and temperature on structural evolution of Au nanowires under torsion

NASA Astrophysics Data System (ADS)

Wu, Cheng-Da; Tsai, Hsing-Wei

2018-06-01

The effect of temperature on the structural evolution of nanocrystalline (NC) and single-crystalline (SC) Au nanowires (NWs) under torsional deformation is studied using molecular dynamics simulations based on the many-body embedded-atom potential. The effect is investigated using common neighbor analysis and discussed in terms of shear strain distribution and atomic flow field. The simulation results show that deformation for NC NWs is mainly driven by the nucleation and propagation of dislocations and the gliding of grain boundaries (GBs) and that for SC NWs is mainly driven by dislocations and the formation of disordered structures. Dislocations for NC and SC NWs easily nucleate at GBs and free surfaces, respectively. For NC NWs, torsional buckling occurs easily at GBs with large gliding. SC NWs have a more uniform and larger elastic deformation under torsion compared to that for NC NWs due to the former's lack of grains. SC NWs have a long period of elastic deformation transforming into plastic deformation. Increasing temperature facilitates stress transmission throughout NWs.

Factor Structure and Scale Reliabilities of the Adjective Check List Across Time

ERIC Educational Resources Information Center

Miller, Stephen H.; And Others

1978-01-01

Investigated factor structure and scale reliabilities of Gough's Adjective Check List (ACL) and their stability over time. Employees in a community mental health center completed the ACL twice, separated by a one-year interval. After each administration, separate factor analyses were computed. All scales had highly significant test-retest…

Industry Efficiency and Total Factor Productivity Growth under Resources and Environmental Constraint in China

PubMed Central

Tao, Feng; Li, Ling; Xia, X. H.

2012-01-01

The growth of China's industry has been seriously depending on energy and environment. This paper attempts to apply the directional distance function and the Luenberger productivity index to measure the environmental efficiency, environmental total factor productivity, and its components at the level of subindustry in China over the period from 1999 to 2009 while considering energy consumption and emission of pollutants. This paper also empirically examines the determinants of efficiency and productivity change. The major findings are as follows. Firstly, the main sources of environmental inefficiency of China's industry are the inefficiency of gross industrial output value, the excessive energy consumption, and pollutant emissions. Secondly, the highest growth rate of environmental total factor productivity among the three industrial categories is manufacturing, followed by mining, and production and supply of electricity, gas, and water. Thirdly, foreign direct investment, capital-labor ratio, ownership structure, energy consumption structure, and environmental regulation have varying degrees of effects on the environmental efficiency and environmental total factor productivity. PMID:23365517

Industry efficiency and total factor productivity growth under resources and environmental constraint in China.

PubMed

Tao, Feng; Li, Ling; Xia, X H

2012-01-01

The growth of China's industry has been seriously depending on energy and environment. This paper attempts to apply the directional distance function and the Luenberger productivity index to measure the environmental efficiency, environmental total factor productivity, and its components at the level of subindustry in China over the period from 1999 to 2009 while considering energy consumption and emission of pollutants. This paper also empirically examines the determinants of efficiency and productivity change. The major findings are as follows. Firstly, the main sources of environmental inefficiency of China's industry are the inefficiency of gross industrial output value, the excessive energy consumption, and pollutant emissions. Secondly, the highest growth rate of environmental total factor productivity among the three industrial categories is manufacturing, followed by mining, and production and supply of electricity, gas, and water. Thirdly, foreign direct investment, capital-labor ratio, ownership structure, energy consumption structure, and environmental regulation have varying degrees of effects on the environmental efficiency and environmental total factor productivity.

Active stabilization of thin-wall structures under compressive loading

NASA Astrophysics Data System (ADS)

Welham, Jared; Calius, Emilio P.; Chase, J. Geoffrey

2003-08-01

The active suppression of elastic buckling instability has the potential to significantly increase the effective strength of thin-wall structures. Despite all the interest in smart structures, the active suppression of buckling has received comparatively little attention. This paper addresses the effects of embedded actuation on the compression buckling strength of laminated composite plates through analysis and simulation. Numerical models are formulated that include the influence of essential features such as sensor uncertainty and noise, actuator saturation and control architecture on the buckling process. Silicon-based strain sensors and diffuse laser distance sensors are both considered for use in the detection of incipient buckling behavior due to their increased sensitivity. Actuation is provided by paired distributions of piezo-electric material incorporated into both sides of the laminate. Optimal controllers are designed to command the structure to deform in ways that interfere with the development of buckling mode shapes. Commercial software packages are used to solve the resulting non-linear equations, and some of the tradeoffs are enumerated. Overall, the results show that active buckling control can considerably enhance resistance to instability under compressive loads. These buckling load predictions demonstrate the viability of optimal control and piezo-electric actuation for implementing active buckling control. Due to the importance of early detection, the relative effectiveness of active buckling control is shown to be strongly dependent on the performance of the sensing scheme, as well as on the characteristics of the structure.

A stochastic global identification framework for aerospace structures operating under varying flight states

NASA Astrophysics Data System (ADS)

Kopsaftopoulos, Fotis; Nardari, Raphael; Li, Yu-Hung; Chang, Fu-Kuo

2018-01-01

In this work, a novel data-based stochastic "global" identification framework is introduced for aerospace structures operating under varying flight states and uncertainty. In this context, the term "global" refers to the identification of a model that is capable of representing the structure under any admissible flight state based on data recorded from a sample of these states. The proposed framework is based on stochastic time-series models for representing the structural dynamics and aeroelastic response under multiple flight states, with each state characterized by several variables, such as the airspeed, angle of attack, altitude and temperature, forming a flight state vector. The method's cornerstone lies in the new class of Vector-dependent Functionally Pooled (VFP) models which allow the explicit analytical inclusion of the flight state vector into the model parameters and, hence, system dynamics. This is achieved via the use of functional data pooling techniques for optimally treating - as a single entity - the data records corresponding to the various flight states. In this proof-of-concept study the flight state vector is defined by two variables, namely the airspeed and angle of attack of the vehicle. The experimental evaluation and assessment is based on a prototype bio-inspired self-sensing composite wing that is subjected to a series of wind tunnel experiments under multiple flight states. Distributed micro-sensors in the form of stretchable sensor networks are embedded in the composite layup of the wing in order to provide the sensing capabilities. Experimental data collected from piezoelectric sensors are employed for the identification of a stochastic global VFP model via appropriate parameter estimation and model structure selection methods. The estimated VFP model parameters constitute two-dimensional functions of the flight state vector defined by the airspeed and angle of attack. The identified model is able to successfully represent the wing

The factor structure of posttraumatic stress disorder: a literature update, critique of methodology, and agenda for future research.

PubMed

Elhai, Jon D; Palmieri, Patrick A

2011-08-01

We present an update of recent literature (since 2007) exploring the factor structure of posttraumatic stress disorder (PTSD) symptom measures. Research supporting a four-factor emotional numbing model and a four-factor dysphoria model is presented, with these models fitting better than all other models examined. Variables accounting for factor structure differences are reviewed, including PTSD query instructions, type of PTSD measure, extent of trauma exposure, ethnicity, and timing of administration. Methodological and statistical limitations with recent studies are presented. Finally, a research agenda and recommendations are offered to push this research area forward, including suggestions to validate PTSD’s factors against external measures of psychopathology, test moderators of factor structure, and examine heterogeneity of symptom presentations based on factor structure examination.

Structural outline of the detailed mechanism for elongation factor Ts-mediated guanine nucleotide exchange on elongation factor Tu.

PubMed

Thirup, Søren S; Van, Lan Bich; Nielsen, Tine K; Knudsen, Charlotte R

2015-07-01

Translation elongation factor EF-Tu belongs to the superfamily of guanine-nucleotide binding proteins, which play key cellular roles as regulatory switches. All G-proteins require activation via exchange of GDP for GTP to carry out their respective tasks. Often, guanine-nucleotide exchange factors are essential to this process. During translation, EF-Tu:GTP transports aminoacylated tRNA to the ribosome. GTP is hydrolyzed during this process, and subsequent reactivation of EF-Tu is catalyzed by EF-Ts. The reaction path of guanine-nucleotide exchange is structurally poorly defined for EF-Tu and EF-Ts. We have determined the crystal structures of the following reaction intermediates: two structures of EF-Tu:GDP:EF-Ts (2.2 and 1.8Å resolution), EF-Tu:PO4:EF-Ts (1.9Å resolution), EF-Tu:GDPNP:EF-Ts (2.2Å resolution) and EF-Tu:GDPNP:pulvomycin:Mg(2+):EF-Ts (3.5Å resolution). These structures provide snapshots throughout the entire exchange reaction and suggest a mechanism for the release of EF-Tu in its GTP conformation. An inferred sequence of events during the exchange reaction is presented. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Dynamics of water confined in lyotropic liquid crystals: Molecular dynamics simulations of the dynamic structure factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mantha, Sriteja; Yethiraj, Arun

2016-02-24

The properties of water under confinement are of practical and fundamental interest. Here in this work we study the properties of water in the self-assembled lyotropic phases of gemini surfactants with a focus on testing the standard analysis of quasi-elastic neutron scattering (QENS) experiments. In QENS experiments the dynamic structure factor is measured and fit to models to extract the translational diffusion constant, D T , and rotational relaxation time, τ R. We test this procedure by using simulation results for the dynamic structure factor, extracting the dynamic parameters from the fit as is typically done in experiments, and comparingmore » the values to those directly measured in the simulations. We find that the decoupling approximation, where the intermediate scattering function is assumed to be a product of translational and rotational contributions, is quite accurate. The jump-diffusion and isotropic rotation models, however, are not accurate when the degree of confinement is high. In particular, the exponential approximations for the intermediate scattering function fail for highly confined water and the values of D T and τ R can differ from the measured value by as much as a factor of two. Other models have more fit parameters, however, and with the range of energies and wave-vectors accessible to QENS, the typical analysis appears to be the best choice. In the most confined lamellar phase, the dynamics are sufficiently slow that QENS does not access a large enough time scale and neutron spin echo measurements would be a valuable technique in addition to QENS.« less

Factor structure of the Spanish version of the Patient Health Questionnaire-9 in Mexican women.

PubMed

Familiar, Itziar; Ortiz-Panozo, Eduardo; Hall, Brian; Vieitez, Isabel; Romieu, Isabelle; Lopez-Ridaura, Ruy; Lajous, Martin

2015-03-01

Structure of the Spanish version of the nine-item Patient Health Questionnaire (PHQ-9) has been inconclusive. We report the factor structure of the PHQ-9 in 55,555 women from the Mexican Teachers' Cohort (MTC). Factor structure of the PHQ-9 was assessed by exploratory and confirmatory factor analyses in two sub-samples (n = 27,778 and 27,777 respectively). A one-factor model of the PHQ-9 was the solution with the best fit to the data, exhibiting strong factor loadings (0.71 to 0.90) and high internal consistency (Cronbach's alpha = 0.89). A prevalence rate of moderate to high severity of depressive symptoms of 12.6% was identified. Results suggest that a global score is an appropriate measure of depressive symptoms and commend the use of the Spanish PHQ-9 as a measure of depression for research and clinical purposes. Copyright © 2014 John Wiley & Sons, Ltd.

Bayes Factor Covariance Testing in Item Response Models.

PubMed

Fox, Jean-Paul; Mulder, Joris; Sinharay, Sandip

2017-12-01

Two marginal one-parameter item response theory models are introduced, by integrating out the latent variable or random item parameter. It is shown that both marginal response models are multivariate (probit) models with a compound symmetry covariance structure. Several common hypotheses concerning the underlying covariance structure are evaluated using (fractional) Bayes factor tests. The support for a unidimensional factor (i.e., assumption of local independence) and differential item functioning are evaluated by testing the covariance components. The posterior distribution of common covariance components is obtained in closed form by transforming latent responses with an orthogonal (Helmert) matrix. This posterior distribution is defined as a shifted-inverse-gamma, thereby introducing a default prior and a balanced prior distribution. Based on that, an MCMC algorithm is described to estimate all model parameters and to compute (fractional) Bayes factor tests. Simulation studies are used to show that the (fractional) Bayes factor tests have good properties for testing the underlying covariance structure of binary response data. The method is illustrated with two real data studies.

The Work Role Functioning Questionnaire v2.0 Showed Consistent Factor Structure Across Six Working Samples.

PubMed

Abma, Femke I; Bültmann, Ute; Amick Iii, Benjamin C; Arends, Iris; Dorland, Heleen F; Flach, Peter A; van der Klink, Jac J L; van de Ven, Hardy A; Bjørner, Jakob Bue

2017-09-09

Objective The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons' health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands with mixed clinical conditions and job types to evaluate the comparability of the scale structure. Methods Confirmatory factor and multi-group analyses were conducted in six cross-sectional working samples (total N = 2433) to evaluate and compare a five-factor model structure of the WRFQ (work scheduling demands, output demands, physical demands, mental and social demands, and flexibility demands). Model fit indices were calculated based on RMSEA ≤ 0.08 and CFI ≥ 0.95. After fitting the five-factor model, the multidimensional structure of the instrument was evaluated across samples using a second order factor model. Results The factor structure was robust across samples and a multi-group model had adequate fit (RMSEA = 0.63, CFI = 0.972). In sample specific analyses, minor modifications were necessary in three samples (final RMSEA 0.055-0.080, final CFI between 0.955 and 0.989). Applying the previous first order specifications, a second order factor model had adequate fit in all samples. Conclusion A five-factor model of the WRFQ showed consistent structural validity across samples. A second order factor model showed adequate fit, but the second order factor loadings varied across samples. Therefore subscale scores are recommended to compare across different clinical and working samples.

A WRKY Transcription Factor Regulates Fe Translocation under Fe Deficiency.

PubMed

Yan, Jing Ying; Li, Chun Xiao; Sun, Li; Ren, Jiang Yuan; Li, Gui Xin; Ding, Zhong Jie; Zheng, Shao Jian

2016-07-01

Iron (Fe) deficiency affects plant growth and development, leading to reduction of crop yields and quality. Although the regulation of Fe uptake under Fe deficiency has been well studied in the past decade, the regulatory mechanism of Fe translocation inside the plants remains unknown. Here, we show that a WRKY transcription factor WRKY46 is involved in response to Fe deficiency. Lack of WRKY46 (wrky46-1 and wrky46-2 loss-of-function mutants) significantly affects Fe translocation from root to shoot and thus causes obvious chlorosis on the new leaves under Fe deficiency. Gene expression analysis reveals that expression of a nodulin-like gene (VACUOLAR IRON TRANSPORTER1-LIKE1 [VITL1]) is dramatically increased in wrky46-1 mutant. VITL1 expression is inhibited by Fe deficiency, while the expression of WRKY46 is induced in the root stele. Moreover, down-regulation of VITL1 expression can restore the chlorosis phenotype on wrky46-1 under Fe deficiency. Further yeast one-hybrid and chromatin immunoprecipitation experiments indicate that WRKY46 is capable of binding to the specific W-boxes present in the VITL1 promoter. In summary, our results demonstrate that WRKY46 plays an important role in the control of root-to-shoot Fe translocation under Fe deficiency condition via direct regulation of VITL1 transcript levels. © 2016 American Society of Plant Biologists. All Rights Reserved.

Stress Intensity Factors for Cracking Metal Structures under Rapid Thermal Loading. Volume 2. Theoretical Background

DTIC Science & Technology

1989-08-01

thermal pulse loadings. The work couples a Green’s function integration technique for transient thermal stresses with the well-known influence ... function approach for calculating stress intensity factors. A total of seven most commonly used crack models were investigated in this study. A computer

Factor Structure of the Korean Version of Wong and Law's Emotional Intelligence Scale

ERIC Educational Resources Information Center

Fukuda, Eriko; Saklofske, Donald H.; Tamaoka, Katsuo; Lim, Hyunjung

2012-01-01

This study reports the factor structure of a Korean version of the 16-item Wong and Law Emotional Intelligence Scale (WLEIS) for a sample of 161 Korean university students. Confirmatory factor analysis supported the four-factor model of the WLEIS: (1) self-emotional appraisal, (2) others' emotional appraisal, (3) use of emotion, and (4) regulation…

Attitudes Toward Seeking Professional Psychological Help: Factor Structure and Socio-Demographic Predictors

PubMed Central

Picco, Louisa; Abdin, Edimanysah; Chong, Siow Ann; Pang, Shirlene; Shafie, Saleha; Chua, Boon Yiang; Vaingankar, Janhavi A.; Ong, Lue Ping; Tay, Jenny; Subramaniam, Mythily

2016-01-01

Attitudes toward seeking professional psychological help (ATSPPH) are complex. Help seeking preferences are influenced by various attitudinal and socio-demographic factors and can often result in unmet needs, treatment gaps, and delays in help-seeking. The aims of the current study were to explore the factor structure of the ATSPPH short form (-SF) scale and determine whether any significant socio-demographic differences exist in terms of help-seeking attitudes. Data were extracted from a population-based survey conducted among Singapore residents aged 18–65 years. Respondents provided socio-demographic information and were administered the ATSPPH-SF. Weighted mean and standard error of the mean were calculated for continuous variables, and frequencies and percentages for categorical variables. Confirmatory factor analysis and exploratory factor analysis were performed to establish the validity of the factor structure of the ATSPPH-SF scale. Multivariable linear regressions were conducted to examine predictors of each of the ATSPPH-SF factors. The factor analysis revealed that the ATSPPH-SF formed three distinct dimensions: “Openness to seeking professional help,” “Value in seeking professional help,” and “Preference to cope on one's own.” Multiple linear regression analyses showed that age, ethnicity, marital status, education, and income were significantly associated with the ATSPPH-SF factors. Population subgroups that were less open to or saw less value in seeking psychological help should be targeted via culturally appropriate education campaigns and tailored and supportive interventions. PMID:27199794

Structure of human thymidylate synthase under low-salt conditions.

PubMed

Lovelace, Leslie L; Minor, Wladek; Lebioda, Lukasz

2005-05-01

Human thymidylate synthase, a target in cancer chemotherapy, was crystallized from PEG 3350 with 30 mM ammonium sulfate (AS) in the crystallization medium. The crystals are isomorphous with the high-salt crystals ( approximately 2.0 M AS) and the structure has been solved and refined (R = 22.6%, R(free) = 24.3%) at 1.8 A resolution. The high- and low-AS-concentration structures are quite similar, with loop 181-197 is in the inactive conformation. Also, residues 95-106 and 129-135 (eukaryotic inserts region) show high mobility as assessed by poor electron density and high values of crystallographic temperature factors (residues 1-25 and 108-129 are disordered in both structures). The high mobility of this region may reflect the situation at physiological ionic strength. Of the four sulfate ions observed bound at 2.0 M AS, only two are present at 30 mM AS. The inactive conformation appears to be stabilized by the side chain of Val3 or a leucine residue from the disordered regions. The low-salt conditions of these crystals should be much more suitable for the study of thymidylate synthase inhibitors, especially those that utilize sulfate-binding sites to stabilize the inactive conformation of loop 181-197.

A dynamic social systems model for considering structural factors in HIV prevention and detection

PubMed Central

Latkin, Carl; Weeks, Margaret; Glasman, Laura; Galletly, Carol; Albarracin, Dolores

2010-01-01

We present a model for HIV-related behaviors that emphasizes the dynamic and social nature of the structural factors that influence HIV prevention and detection. Key structural dimensions of the model include resources, science and technology, formal social control, informal social influences and control, social interconnectedness, and settings. These six dimensions can be conceptualized on macro, meso, and micro levels. Given the inherent complexity of structural factors and their interrelatedness, HIV prevention interventions may focus on different levels and dimensions. We employ a systems perspective to describe the interconnected and dynamic processes of change among social systems and their components. The topics of HIV testing and safer injection facilities are analyzed using this structural framework. Finally, we discuss methodological issues in the development and evaluation of structural interventions for HIV prevention and detection. PMID:20838871

Dynamical quadrupole structure factor of frustrated ferromagnetic chain

NASA Astrophysics Data System (ADS)

Onishi, Hiroaki

2018-05-01

We investigate the dynamical quadrupole structure factor of a spin-1/2 J1-J2 Heisenberg chain with competing ferromagnetic J1 and antiferromagnetic J2 in a magnetic field by exploiting density-matrix renormalization group techniques. In a field-induced spin nematic regime, we observe gapless excitations at q = π according to quasi-long-range antiferro-quadrupole correlations. The gapless excitation mode has a quadratic form at the saturation, while it changes into a linear dispersion as the magnetization decreases.

B1 to B2 structural phase transition in LiF under pressure

NASA Astrophysics Data System (ADS)

Jain, Aayushi; Dixit, R. C.

2018-05-01

In the last few decades the alkali halides emerged as crystals with useful applications and their high-pressure behaviour is the most intensively studied subject in high-pressure physics/chemistry, material science, and geosciences. Most alkali halides follow the B1 (NaCl-type)→B2 (CsCl-type) phase-transition route under pressure. In the present paper, we have investigated the characteristics of structural phase transition that occurred in Lithium Florid compound under high pressure. The transition pressure of B1-B2 was calculated using an effective interionic interaction potential (EIOP). The changes of the characteristics of crystals like, Gibbs free energy, cohesive energy, volume collapse, and lattice constant are calculated for the B1 and B2 structures. These data were compared with the available experimental and theoretical data.

Partial structure factors reveal atomic dynamics in metallic alloy melts

NASA Astrophysics Data System (ADS)

Nowak, B.; Holland-Moritz, D.; Yang, F.; Voigtmann, Th.; Kordel, T.; Hansen, T. C.; Meyer, A.

2017-07-01

We investigate the dynamical decoupling of the diffusion coefficients of the different components in a metallic alloy melt, using a combination of neutron diffraction, isotopic substitution, and electrostatic levitation in Zr-Ni melts. We show that excess Ni atoms can diffuse more freely in a background of saturated chemical interaction, causing their dynamics to become much faster and thus decoupled than anticipated from the interparticle interactions. Based on the mode-coupling theory of the glass transition, the averaged structure as given by the partial static structure factors is able to explain the observed dynamical behavior.

SM-TF: A structural database of small molecule-transcription factor complexes.

PubMed

Xu, Xianjin; Ma, Zhiwei; Sun, Hongmin; Zou, Xiaoqin

2016-06-30

Transcription factors (TFs) are the proteins involved in the transcription process, ensuring the correct expression of specific genes. Numerous diseases arise from the dysfunction of specific TFs. In fact, over 30 TFs have been identified as therapeutic targets of about 9% of the approved drugs. In this study, we created a structural database of small molecule-transcription factor (SM-TF) complexes, available online at http://zoulab.dalton.missouri.edu/SM-TF. The 3D structures of the co-bound small molecule and the corresponding binding sites on TFs are provided in the database, serving as a valuable resource to assist structure-based drug design related to TFs. Currently, the SM-TF database contains 934 entries covering 176 TFs from a variety of species. The database is further classified into several subsets by species and organisms. The entries in the SM-TF database are linked to the UniProt database and other sequence-based TF databases. Furthermore, the druggable TFs from human and the corresponding approved drugs are linked to the DrugBank. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Factor structure and correlates of the Mandarin version of the Managing the Emotions of Others (MEOS) scale.

PubMed

Saklofske, Donald H; Austin, Elizabeth J; Yan, Gonggu; Smith, Martin M

2016-02-01

The English-language version of the Managing the Emotions of Others (MEOS) scale has been found to have a six-factor structure. This includes two pairs (Enhance, Divert and Worsen, Inauthentic) that respectively describe prosocial and non-prosocial interpersonal emotion management, together with an emotional concealment factor (Conceal) and a factor assessing poor self-rated emotional skills. A Mandarin translation of the MEOS was completed by 277 Chinese student participants. Factor analysis indicated a four-factor structure comprising a merged Enhance/Divert factor, together with Worsen, Inauthentic and Conceal factors. The emergence of a different factor structure compared to Western samples may be related to culture-dependent attitudes to emotional expression. The associations of the MEOS factors with Five-Factor model personality, the Dark Triad and trait emotional intelligence (EI) were examined; these were similar to but generally weaker than those found for the English-language version. © 2015 International Union of Psychological Science.

[Factor structure validity of the social capital scale used at baseline in the ELSA-Brasil study].

PubMed

Souto, Ester Paiva; Vasconcelos, Ana Glória Godoi; Chor, Dora; Reichenheim, Michael E; Griep, Rosane Härter

2016-07-21

This study aims to analyze the factor structure of the Brazilian version of the Resource Generator (RG) scale, using baseline data from the Brazilian Longitudinal Health Study in Adults (ELSA-Brasil). Cross-validation was performed in three random subsamples. Exploratory factor analysis using exploratory structural equation models was conducted in the first two subsamples to diagnose the factor structure, and confirmatory factor analysis was used in the third to corroborate the model defined by the exploratory analyses. Based on the 31 initial items, the model with the best fit included 25 items distributed across three dimensions. They all presented satisfactory convergent validity (values greater than 0.50 for the extracted variance) and precision (values greater than 0.70 for compound reliability). All factor correlations were below 0.85, indicating full discriminative factor validity. The RG scale presents acceptable psychometric properties and can be used in populations with similar characteristics.

Coopersmith Self-Esteem: Two Different Hypothesized Factor Models--Both Acceptable for the Same Data Structure.

ERIC Educational Resources Information Center

Hofmann, Rich; Sherman, Larry

Using data from 135 sixth-, seventh-, and eighth-graders between 11 and 15 years old attending a middle school in a suburban Southwest Ohio school district, two hypothesized models of the factor structures for the Coopersmith Self-Esteem Inventory were tested. One model represents the original Coopersmith factor structure, and the other model is…

Structural modeling of carbonaceous mesophase amphotropic mixtures under uniaxial extensional flow.

PubMed

Golmohammadi, Mojdeh; Rey, Alejandro D

2010-07-21

The extended Maier-Saupe model for binary mixtures of model carbonaceous mesophases (uniaxial discotic nematogens) under externally imposed flow, formulated in previous studies [M. Golmohammadi and A. D. Rey, Liquid Crystals 36, 75 (2009); M. Golmohammadi and A. D. Rey, Entropy 10, 183 (2008)], is used to characterize the effect of uniaxial extensional flow and concentration on phase behavior and structure of these mesogenic blends. The generic thermorheological phase diagram of the single-phase binary mixture, given in terms of temperature (T) and Deborah (De) number, shows the existence of four T-De transition lines that define regions that correspond to the following quadrupolar tensor order parameter structures: (i) oblate (perpendicular, parallel), (ii) prolate (perpendicular, parallel), (iii) scalene O(perpendicular, parallel), and (iv) scalene P(perpendicular, parallel), where the symbols (perpendicular, parallel) indicate alignment of the tensor order ellipsoid with respect to the extension axis. It is found that with increasing T the dominant component of the mixture exhibits weak deviations from the well-known pure species response to uniaxial extensional flow (uniaxial perpendicular nematic-->biaxial nematic-->uniaxial parallel paranematic). In contrast, the slaved component shows a strong deviation from the pure species response. This deviation is dictated by the asymmetric viscoelastic coupling effects emanating from the dominant component. Changes in conformation (oblate <==> prolate) and orientation (perpendicular <==> parallel) are effected through changes in pairs of eigenvalues of the quadrupolar tensor order parameter. The complexity of the structural sensitivity to temperature and extensional flow is a reflection of the dual lyotropic/thermotropic nature (amphotropic nature) of the mixture and their cooperation/competition. The analysis demonstrates that the simple structures (biaxial nematic and uniaxial paranematic) observed in pure discotic

Exploring the underlying factors influencing e-learning adoption in nurse education.

PubMed

Petit dit Dariel, Odessa; Wharrad, Heather; Windle, Richard

2013-06-01

To report a study undertaken to explore the underlying factors influencing e-learning adoption in nurse education. Despite e-learning's high profile it has not been readily integrated into teaching practice in nurse education. Previous research has identified generic, cross-disciplinary factors but has left out 'soft' factors. The study adopted an exploratory descriptive design. Q-methodology was used to explore e-learning adoption in a Division of Nursing located in an institution of Higher Education in the UK. Between September-December 2009, 38 participants were recruited to participate in Q-sorts and post-sort interviews. The Q-sort data were factor analysed and the interviews were coded to their respective factors to develop in-depth narratives. Four factors were identified: 'E-learning advocates' saw e-learning's potential to improve nurse education and prepare future nurses for their evolving role; the 'Humanists' had avoided e-learning because they valued human interaction; the 'Sceptics' doubted that technology could improve learning outcomes; and the 'Pragmatics,' only used e-learning as a tool to post lecture notes online to supplement what they covered in class. The findings point to the variety of responses existing among nurse academics faced with integrating e-learning into their teaching. Moving beyond the binary labels commonly attributed to those considered either 'early adopters' or 'laggards,' the findings contribute to the literature by revealing a wider breadth of views and responses towards technology. Acknowledging these views can inform future e-learning strategies and lead to improvement in e-learning use in nurse education. © 2012 Blackwell Publishing Ltd.

[Does the GHQ-12 scoring system affect its factor structure? An exploratory study of Ibero American students].

PubMed

Urzúa, Alfonso; Caqueo-Urízar, Alejandra; Bargsted, Mariana; Irarrázaval, Matías

2015-06-01

This study aimed to evaluate whether the scoring system of the General Health Questionnaire (GHQ-12) alters the instrument's factor structure. The method considered 1,972 university students from nine Ibero American countries. Modeling was performed with structural equations for 1, 2, and 3 latent factors. The mechanism for scoring the questions was analyzed within each type of structure. The results indicate that models with 2 and 3 factors show better goodness-of-fit. In relation to scoring mechanisms, procedure 0-1-1-1 for models with 2 and 3 factors showed the best fit. In conclusion, there appears to be a relationship between the response format and the number of factors identified in the instrument's structure. The model with the best fit was 3-factor 0-1-1-1-formatted, but 0-1-2-3 has acceptable and more stable indicators and provides a better format for two- and three-dimensional models.

The quasi-equilibrium response of MOS structures: Quasi-static factor

NASA Astrophysics Data System (ADS)

Okeke, M.; Balland, B.

1984-07-01

The dynamic response of a MOS structure driven into a non-equilibrium behaviour by a voltage ramp is presented. In contrast to Khun's quasi-static technique it is shown that any ramp-driven MOS structure has some degree of non-equilibrium. A quasi staticity factor μAK which serves as a measure of the degree of quasi-equilibrium, has been introduced for the first time. The mathematical model presented in the paper allows a better explanation of the experimental recordings. It is shown that this model could be used to analyse the various features of the response of the structure and that such physical parameters as the generation-rate, trap activation energy, and the effective capture constants could be obtained.

Factor Structure of the Kessler Psychological Distress Scale (K6) among Emerging Adults

ERIC Educational Resources Information Center

Bessaha, Melissa L.

2017-01-01

Objective: Confirmatory factor analysis was used to assess the factor structure of the 6-item version of the Kessler Psychological Distress Scale (K6). Methods: A subsample of emerging adults, aged 18-29 (n = 20,699), from the 2013 National Survey of Drug Use and Health were used in this study. Results: Each of the models (one-factor, two-factor…

X-ray Intermolecular Structure Factor ( XISF ): separation of intra- and intermolecular interactions from total X-ray scattering data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mou, Q.; Benmore, C. J.; Yarger, J. L.

2015-05-09

XISFis a MATLAB program developed to separate intermolecular structure factors from total X-ray scattering structure factors for molecular liquids and amorphous solids. The program is built on a trust-region-reflective optimization routine with the r.m.s. deviations of atoms physically constrained.XISFhas been optimized for performance and can separate intermolecular structure factors of complex molecules.

The factor structure of complex posttraumatic stress disorder in traumatized refugees.

PubMed

Nickerson, Angela; Cloitre, Marylene; Bryant, Richard A; Schnyder, Ulrich; Morina, Naser; Schick, Matthis

2016-01-01

The construct of complex posttraumatic stress disorder (CPTSD) has attracted much research attention in previous years, however it has not been systematically evaluated in individuals exposed to persecution and displacement. Given that CPTSD has been proposed as a diagnostic category in the ICD-11, it is important that it be examined in refugee groups. In the current study, we proposed to test, for the first time, the factor structure of CPTSD proposed for the ICD-11 in a sample of resettled treatment-seeking refugees. The study sample consisted of 134 traumatized refugees from a variety of countries of origin, with approximately 93% of the sample having been exposed to torture. We used confirmatory factor analysis to examine the factor structure of CPTSD in this sample and examined the sensitivity, specificity, positive predictive power and negative predictive power of individual items in relation to the CPTSD diagnosis. Findings revealed that a two-factor higher-order model of CPTSD comprising PTSD and Difficulties in Self-Organization (χ 2 (47)=57.322, p =0.144, RMSEA=0.041, CFI=0.981, TLI=0.974) evidenced superior fit compared to a one-factor higher-order model of CPTSD (χ 2 (48)=65.745, p =0.045, RMSEA=0.053, CFI=0.968, TLI=0.956). Overall, items evidenced strong sensitivity and negative predictive power, moderate positive predictive power, and poor specificity. Findings provide preliminary evidence for the validity of the CPTSD construct with highly traumatized treatment-seeking refugees.

The Strengths and Difficulties Questionnaire (SDQ): Factor Structure and Gender Equivalence in Norwegian Adolescents.

PubMed

Bøe, Tormod; Hysing, Mari; Skogen, Jens Christoffer; Breivik, Kyrre

2016-01-01

Although frequently used with older adolescents, few studies of the factor structure, internal consistency and gender equivalence of the SDQ exists for this age group, with inconsistent findings. In the present study, confirmatory factor analysis (CFA) was used to evaluate the five-factor structure of the SDQ in a population sample of 10,254 16-18 year-olds from the youth@hordaland study. Measurement invariance across gender was assessed using multigroup CFA. A modestly modified five-factor solution fitted the data acceptably, accounting for one cross loading and some local dependencies. Importantly, partial measurement non-invariance was identified, with differential item functioning in eight items, and higher correlations between emotional and conduct problems for boys compared to girls. Implications for use clinically and in research are discussed.

Factor Structure of the WPPSI in Mental Health Clinic Settings.

ERIC Educational Resources Information Center

Haynes, Jack P.; Atkinson, David

1984-01-01

Factor-analyzed the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) scores of emotionally disturbed children (N=181). The results suggested that the structure of intelligence for emotionally disturbed children is similar to that for normal children. WPPSI profile analysis that uses subtest scores may be invalid in clinical settings.…

Undersize solute element effects on defect structure development in copper under electron irradiation

NASA Astrophysics Data System (ADS)

Satoh, Y.; Yoshiie, T.; Arai, S.

2018-03-01

We conducted systematic experiments of defect structure development in Cu base binary alloys under 1000 kV electron irradiation at temperatures higher than 300 K, using in situ observations with high voltage electron microscopy. This report describes the effects of undersize elements: Co (-3.78%), Ni (-8.45%) and Be (-26.45%). The volume size factors are given in parentheses. The amounts of the respective elements were 2, 0.3, 0.05 at.%, or less. In Cu-Ni and Cu-Co and in the reference Cu, temperature dependence of the number density of interstitial-type dislocation loops had a down peak (i.e. loops hardly formed) at approximately 373 K, attributed to unexpected impurity atoms. Above the down-peak temperature, the addition of Co or Ni increased the loop number density through continuous nucleation of loops, extended the loop formation to higher temperatures, and decreased the apparent activation energy of loop growth rate. The addition of Be for 0.3 at.% or more delayed loop formation after formation of stacking fault tetrahedra (SFTs) around 300 K. The apparent mobility of self-interstitial atoms is expected to be smaller than that of vacancies because of strong binding with Be. Loop formation at temperatures higher than 373 K was enhanced by Be for 0.3 or 2 at.%, although it was suppressed greatly for 0.05 at.% or less. All undersize atoms increased the stability of SFTs under irradiation. Mechanisms of those effects were discussed and were briefly compared with earlier results found for oversize elements in Cu.

24 CFR 1000.160 - Are non-dwelling structures developed, acquired or assisted under the IHBG program subject to...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Are non-dwelling structures developed, acquired or assisted under the IHBG program subject to limitations on cost or design standards...-dwelling structures developed, acquired or assisted under the IHBG program subject to limitations on cost...

24 CFR 1000.160 - Are non-dwelling structures developed, acquired or assisted under the IHBG program subject to...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Are non-dwelling structures developed, acquired or assisted under the IHBG program subject to limitations on cost or design standards...-dwelling structures developed, acquired or assisted under the IHBG program subject to limitations on cost...

Factor Structure of the Wechsler Intelligence Scale for Children: Fourth Edition in Children with ADHD.

PubMed

Thaler, Nicholas S; Barchard, Kimberly A; Parke, Elyse; Jones, W Paul; Etcoff, Lewis M; Allen, Daniel N

2015-12-01

Recent evidence suggests that the factor structure of the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) is better explained by a five-factor model rather than the four-factor model in the standardization sample. The current study examined the WISC-IV's factor structure in a sample of children with ADHD. Participants included 314 children and adolescents who were diagnosed with ADHD. Confirmatory factor analysis was conducted on the 10 core subtests of the WISC-IV, and three models were examined including two based on Cattell-Horn-Carroll (CHC) theory. A five-factor model consisting of Gc, Gf, Gv, Gsm, and Gs factors provided the best fit for the data. The Perceptual Reasoning factor identified in the original four-factor model split into the two CHC factors, Gf and Gv, and cross-loaded the Symbol Search subtest onto the Gv factor. A five-factor model based on CHC theory provided superior fit for the WISC-IV in children with ADHD, as has been found with the standardization sample. © The Author(s) 2012.

Factor structure of the Childhood Autism Rating Scale as per DSM-5.

PubMed

Park, Eun-Young; Kim, Joungmin

2016-02-01

The DSM-5 recently proposed new diagnostic criteria for autism spectrum disorder (ASD). Although many new or updated tools have been developed since the DSM-IV was published in 1994, the Childhood Autism Rating Scale (CARS) has been used consistently in ASD diagnosis and research due to its technical adequacy, cost-effectiveness, and practicality. Additionally, items in the CARS did not alter following the release of the revised DSM-IV because the CARS factor structure was found to be consistent with the revised criteria after factor analysis. For that reason, in this study confirmatory factor analysis was used to identify the factor structure of the CARS. Participants (n = 150) consisted of children with an ASD diagnosis or who met the criteria for broader autism or emotional/behavior disorder with comorbid disorders such as attention-deficit hyperactivity disorder, bipolar disorder, intellectual or developmental disabilities. Previous studies used one-, two-, and four-factor models, all of which we examined to confirm the best-fit model on confirmatory factor analysis. Appropriate comparative fit indices and root mean square errors were obtained for all four models. The two-factor model, based on DSM-5 criteria, was the most valid and reliable. The inter-item consistency of the CARS was 0.926 and demonstrated adequate reliability, thereby supporting the validity and reliability of the two-factor model of CARS. Although CARS was developed prior to the introduction of DSM-5, its psychometric properties, conceptual relevance, and flexible administration procedures support its continued role as a screening device in the diagnostic decision-making process. © 2015 Japan Pediatric Society.

Factor Structure and Basic Psychometric Properties of the "Transition Assessment and Goal Generator"

ERIC Educational Resources Information Center

Hennessey, Maeghan N.; Terry, Robert; Martin, James E.; McConnell, Amber E.; Willis, Donna M.

2018-01-01

We examined the theoretical factor structure fit and psychometric properties of the "Transition Assessment and Goal Generator" (TAGG). In the first study, 349 transition-aged students with disabilities, their special educators, and family members completed TAGG assessments, and using exploratory factor analysis (EFA)/confirmatory factor…

Simulation on the internal structure of three-dimensional proximal tibia under different mechanical environments.

PubMed

Fang, Juan; Gong, He; Kong, Lingyan; Zhu, Dong

2013-12-20

Bone can adjust its morphological structure to adapt to the changes of mechanical environment, i.e. the bone structure change is related to mechanical loading. This implies that osteoarthritis may be closely associated with knee joint deformity. The purposes of this paper were to simulate the internal bone mineral density (BMD) change in three-dimensional (3D) proximal tibia under different mechanical environments, as well as to explore the relationship between mechanical environment and bone morphological abnormity. The right proximal tibia was scanned with CT to reconstruct a 3D proximal tibia model in MIMICS, then it was imported to finite element software ANSYS to establish 3D finite element model. The internal structure of 3D proximal tibia of young normal people was simulated using quantitative bone remodeling theory in combination with finite element method, then based on the changing pattern of joint contact force on the tibial plateau in valgus knees, the mechanical loading was changed, and the simulated normal tibia structure was used as initial structure to simulate the internal structure of 3D proximal tibia for old people with 6° valgus deformity. Four regions of interest (ROIs) were selected in the proximal tibia to quantitatively analyze BMD and compare with the clinical measurements. The simulation results showed that the BMD distribution in 3D proximal tibia was consistent with clinical measurements in normal knees and that in valgus knees was consistent with the measurement of patients with osteoarthritis in clinics. It is shown that the change of mechanical environment is the main cause for the change of subchondral bone structure, and being under abnormal mechanical environment for a long time may lead to osteoarthritis. Besides, the simulation method adopted in this paper can more accurately simulate the internal structure of 3D proximal tibia under different mechanical environments. It helps to better understand the mechanism of

Simulation on the internal structure of three-dimensional proximal tibia under different mechanical environments

PubMed Central

2013-01-01

Background Bone can adjust its morphological structure to adapt to the changes of mechanical environment, i.e. the bone structure change is related to mechanical loading. This implies that osteoarthritis may be closely associated with knee joint deformity. The purposes of this paper were to simulate the internal bone mineral density (BMD) change in three-dimensional (3D) proximal tibia under different mechanical environments, as well as to explore the relationship between mechanical environment and bone morphological abnormity. Methods The right proximal tibia was scanned with CT to reconstruct a 3D proximal tibia model in MIMICS, then it was imported to finite element software ANSYS to establish 3D finite element model. The internal structure of 3D proximal tibia of young normal people was simulated using quantitative bone remodeling theory in combination with finite element method, then based on the changing pattern of joint contact force on the tibial plateau in valgus knees, the mechanical loading was changed, and the simulated normal tibia structure was used as initial structure to simulate the internal structure of 3D proximal tibia for old people with 6° valgus deformity. Four regions of interest (ROIs) were selected in the proximal tibia to quantitatively analyze BMD and compare with the clinical measurements. Results The simulation results showed that the BMD distribution in 3D proximal tibia was consistent with clinical measurements in normal knees and that in valgus knees was consistent with the measurement of patients with osteoarthritis in clinics. Conclusions It is shown that the change of mechanical environment is the main cause for the change of subchondral bone structure, and being under abnormal mechanical environment for a long time may lead to osteoarthritis. Besides, the simulation method adopted in this paper can more accurately simulate the internal structure of 3D proximal tibia under different mechanical environments. It helps to better

Structure of a financial cross-correlation matrix under attack

NASA Astrophysics Data System (ADS)

Lim, Gyuchang; Kim, SooYong; Kim, Junghwan; Kim, Pyungsoo; Kang, Yoonjong; Park, Sanghoon; Park, Inho; Park, Sang-Bum; Kim, Kyungsik

2009-09-01

We investigate the structure of a perturbed stock market in terms of correlation matrices. For the purpose of perturbing a stock market, two distinct methods are used, namely local and global perturbation. The former involves replacing a correlation coefficient of the cross-correlation matrix with one calculated from two Gaussian-distributed time series while the latter reconstructs the cross-correlation matrix just after replacing the original return series with Gaussian-distributed time series. Concerning the local case, it is a technical study only and there is no attempt to model reality. The term ‘global’ means the overall effect of the replacement on other untouched returns. Through statistical analyses such as random matrix theory (RMT), network theory, and the correlation coefficient distributions, we show that the global structure of a stock market is vulnerable to perturbation. However, apart from in the analysis of inverse participation ratios (IPRs), the vulnerability becomes dull under a small-scale perturbation. This means that these analysis tools are inappropriate for monitoring the whole stock market due to the low sensitivity of a stock market to a small-scale perturbation. In contrast, when going down to the structure of business sectors, we confirm that correlation-based business sectors are regrouped in terms of IPRs. This result gives a clue about monitoring the effect of hidden intentions, which are revealed via portfolios taken mostly by large investors.

Factor Structure of a Multidimensional Gender Identity Scale in a Sample of Chinese Elementary School Children

PubMed Central

Yu, Lu; Xie, Dong; Shek, Daniel T. L.

2012-01-01

This study examined the factor structure of a scale based on the four-dimensional gender identity model (Egan and Perry, 2001) in 726 Chinese elementary school students. Exploratory factor analyses suggested a three-factor model, two of which corresponded to “Felt Pressure” and “Intergroup Bias” in the original model. The third factor “Gender Compatibility” appeared to be a combination of “Gender Typicality” and “Gender Contentment” in the original model. Follow-up confirmatory factor analysis (CFA) indicated that, relative to the initial four-factor structure, the three-factor model fits the current Chinese sample better. These results are discussed in light of cross-cultural similarities and differences in development of gender identity. PMID:22701363

Synoptic Factors Affecting Structure Predictability of Hurricane Alex (2016)

NASA Astrophysics Data System (ADS)

Gonzalez-Aleman, J. J.; Evans, J. L.; Kowaleski, A. M.

2016-12-01

On January 7, 2016, a disturbance formed over the western North Atlantic basin. After undergoing tropical transition, the system became the first hurricane of 2016 - and the first North Atlantic hurricane to form in January since 1938. Already an extremely rare hurricane event, Alex then underwent extratropical transition [ET] just north of the Azores Islands. We examine the factors affecting Alex's structural evolution through a new technique called path-clustering. In this way, 51 ensembles from the European Centre for Medium-Range Weather Forecasts Ensemble Prediction System (ECMWF-EPS) are grouped based on similarities in the storm's path through the Cyclone Phase Space (CPS). The differing clusters group various possible scenarios of structural development represented in the ensemble forecasts. As a result, it is possible to shed light on the role of the synoptic scale in changing the structure of this hurricane in the midlatitudes through intercomparison of the most "realistic" forecast of the evolution of Alex and the other physically plausible modes of its development.

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

NASA Astrophysics Data System (ADS)

Wada, Yoshihisa; Tsuji, Hiroshi

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.

Coherent dynamic structure factors of strongly coupled plasmas: A generalized hydrodynamic approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Di; Hu, GuangYue; Gong, Tao

2016-05-15

A generalized hydrodynamic fluctuation model is proposed to simplify the calculation of the dynamic structure factor S(ω, k) of non-ideal plasmas using the fluctuation-dissipation theorem. In this model, the kinetic and correlation effects are both included in hydrodynamic coefficients, which are considered as functions of the coupling strength (Γ) and collision parameter (kλ{sub ei}), where λ{sub ei} is the electron-ion mean free path. A particle-particle particle-mesh molecular dynamics simulation code is also developed to simulate the dynamic structure factors, which are used to benchmark the calculation of our model. A good agreement between the two different approaches confirms the reliabilitymore » of our model.« less

Assessing infertility-related stress: the factor structure of the Fertility Problem Inventory in Italian couples undergoing infertility treatment.

PubMed

Donarelli, Zaira; Gullo, Salvatore; Lo Coco, Gianluca; Marino, Angelo; Scaglione, Piero; Volpes, Aldo; Allegra, Adolfo

2015-01-01

The factor structure of the Fertility Problem Inventory (FPI) and its invariance across gender were examined in Italian couples undergoing infertility treatment. About 1000 subjects (both partners of 500 couples) completed two questionnaires prior to commencing infertility treatment at a private Clinic in Palermo, Italy. Confirmatory Factor Analysis demonstrated that the original factor structure of the FPI was partially confirmed. Two correlated factors (Infertility Life Domains and Importance of Parenthood) were obtained via a post hoc Exploratory Factor Analysis. Finally, the invariance of this factor structure across gender was confirmed. The study supported the relevance of two interrelated factors specific to infertility stress which could help clinicians to focus on the core infertility-related stress domains of infertile couples.

X-ray Intermolecular Structure Factor (XISF): separation of intra- and intermolecular interactions from total X-ray scattering data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mou, Q.; Benmore, C. J.; Yarger, J. L.

2015-06-01

XISF is a MATLAB program developed to separate intermolecular structure factors from total X-ray scattering structure factors for molecular liquids and amorphous solids. The program is built on a trust-region-reflective optimization routine with the r.m.s. deviations of atoms physically constrained. XISF has been optimized for performance and can separate intermolecular structure factors of complex molecules.

Stress Distribution in a Rigidly Clamped Composite Plate with Locally Curved Structures under Forced Vibration

NASA Astrophysics Data System (ADS)

Zamanov, A. D.

2001-09-01

A problem on the forced vibrations of a rectangular composite plate with locally curved structures is formulated using the exact three-dimensional equations of continuum mechanics and continuum theory. A technique for numerical solution of the problem is developed based on the semianalytic finite-element method. Numerical results are given for the stress distribution in the plate under forced vibrations. The results obtained are analyzed to study the effect of the curvature in the structure of the plate on the distribution of stress amplitudes. It is shown that the curvatures change significantly the stress pattern under either static or dynamic loading

Multilevel Factor Structure and Concurrent Validity of the Teacher Version of the Authoritative School Climate Survey.

PubMed

Huang, Francis L; Cornell, Dewey G; Konold, Timothy; Meyer, Joseph P; Lacey, Anna; Nekvasil, Erin K; Heilbrun, Anna; Shukla, Kathan D

2015-12-01

School climate is well recognized as an important influence on student behavior and adjustment to school, but there is a need for theory-guided measures that make use of teacher perspectives. Authoritative school climate theory hypothesizes that a positive school climate is characterized by high levels of disciplinary structure and student support. A teacher version of the Authoritative School Climate Survey (ASCS) was administered to a statewide sample of 9099 7th- and 8th-grade teachers from 366 schools. The study used exploratory and multilevel confirmatory factor analyses (MCFA) that accounted for the nested data structure and allowed for the modeling of the factor structures at 2 levels. Multilevel confirmatory factor analyses conducted on both an exploratory (N = 4422) and a confirmatory sample (N = 4677) showed good support for the factor structures investigated. Factor correlations at 2 levels indicated that schools with greater levels of disciplinary structure and student support had higher student engagement, less teasing and bullying, and lower student aggression toward teachers. The teacher version of the ASCS can be used to assess 2 key domains of school climate and associated measures of student engagement and aggression toward peers and teachers. © 2015, American School Health Association.

Factor Structure and Validation of a Set of Readiness Measures.

ERIC Educational Resources Information Center

Kaufman, Maurice; Lynch, Mervin

A study was undertaken to identify the factor structure of a battery of readiness measures and to demonstrate the concurrent and predictive validity of one instrument in that battery--the Pre-Reading Screening Procedures (PSP). Concurrent validity was determined by examining the correlation of the PSP with the Metropolitan Readiness Test (MRT),…

Factor structure of the Chinese version of the Meaning in Life Questionnaire among Hong Kong Chinese caregivers.

PubMed

Chan, Wallace Chi Ho

2014-08-01

This study examines the factor structure of the Chinese version of the Meaning in Life Questionnaire (C-MLQ) in a sample of Hong Kong Chinese caregivers of patients with chronic illness (N = 223). Confirmatory factor analysis was performed to examine the factor structure. Findings confirm that, identical to the original version, C-MLQ showed the same two-factor structure: Presence and Search. Correlation between Presence and Search was found to be positive and moderate (r = .47). This study establishes empirically the same factor structure as the original version of MLQ among caregivers in Hong Kong. The relationship between Presence and Meaning is discussed in the contexts of Chinese culture and caregiving. Results suggest caregivers' continuing need for meaning in life. Medical social workers may help caregivers to integrate their caregiving experience with their sense of meaning in life and search for meaning in life to sustain their caregiving role.

Exploration of the factor structure of the Kirton Adaption-Innovation Inventory using bootstrapping estimation.

PubMed

Im, Subin; Min, Soonhong

2013-04-01

Exploratory factor analyses of the Kirton Adaption-Innovation Inventory (KAI), which serves to measure individual cognitive styles, generally indicate three factors: sufficiency of originality, efficiency, and rule/group conformity. In contrast, a 2005 study by Im and Hu using confirmatory factor analysis supported a four-factor structure, dividing the sufficiency of originality dimension into two subdimensions, idea generation and preference for change. This study extends Im and Hu's (2005) study of a derived version of the KAI by providing additional evidence of the four-factor structure. Specifically, the authors test the robustness of the parameter estimates to the violation of normality assumptions in the sample using bootstrap methods. A bias-corrected confidence interval bootstrapping procedure conducted among a sample of 356 participants--members of the Arkansas Household Research Panel, with middle SES and average age of 55.6 yr. (SD = 13.9)--showed that the four-factor model with two subdimensions of sufficiency of originality fits the data significantly better than the three-factor model in non-normality conditions.

Giant panda׳s tooth enamel: Structure, mechanical behavior and toughening mechanisms under indentation.

PubMed

Weng, Z Y; Liu, Z Q; Ritchie, R O; Jiao, D; Li, D S; Wu, H L; Deng, L H; Zhang, Z F

2016-12-01

The giant panda׳s teeth possess remarkable load-bearing capacity and damage resistance for masticating bamboos. In this study, the hierarchical structure and mechanical behavior of the giant panda׳s tooth enamel were investigated under indentation. The effects of loading orientation and location on mechanical properties of the enamel were clarified and the evolution of damage in the enamel under increasing load evaluated. The nature of the damage, both at and beneath the indentation surfaces, and the underlying toughening mechanisms were explored. Indentation cracks invariably were seen to propagate along the internal interfaces, specifically the sheaths between enamel rods, and multiple extrinsic toughening mechanisms, e.g., crack deflection/twisting and uncracked-ligament bridging, were active to shield the tips of cracks from the applied stress. The giant panda׳s tooth enamel is analogous to human enamel in its mechanical properties, yet it has superior hardness and Young׳s modulus but inferior toughness as compared to the bamboo that pandas primarily feed on, highlighting the critical roles of the integration of underlying tissues in the entire tooth and the highly hydrated state of bamboo foods. Our objective is that this study can aid the understanding of the structure-mechanical property relations in the tooth enamel of mammals and further provide some insight on the food habits of the giant pandas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Factor Structure and Basic Psychometric Properties of the "Transition Assessment" and "Goal Generator"

ERIC Educational Resources Information Center

Hennessey, Maeghan N.; Terry, Robert; Martin, James E.; McConnell, Amber E.; Willis, Donna M.

2017-01-01

The researchers examined the theoretical factor structure fit and psychometric properties of the Transition Assessment and Goal Generator (TAGG). In the first study, 349 transition-aged students with disabilities, their special educators, and family members completed TAGG assessments, and using exploratory factor analysis (EFA)/confirmatory factor…

Exploratory and Confirmatory Factor Analyses of the Structured Interview for Disorders of Extreme Stress

ERIC Educational Resources Information Center

Scoboria, Alan; Ford, Julian; Lin, Hsiu-ju; Frisman, Linda

2008-01-01

Two studies were conducted to provide the first empirical examination of the factor structure of a revised version of the clinically derived Structured Interview for Disorders of Extreme Stress, a structured interview designed to assess associated features of posttraumatic stress disorder (PTSD) thought to be related to early onset, interpersonal,…

The Strengths and Difficulties Questionnaire (SDQ): Factor Structure and Gender Equivalence in Norwegian Adolescents

PubMed Central

Hysing, Mari; Skogen, Jens Christoffer; Breivik, Kyrre

2016-01-01

Although frequently used with older adolescents, few studies of the factor structure, internal consistency and gender equivalence of the SDQ exists for this age group, with inconsistent findings. In the present study, confirmatory factor analysis (CFA) was used to evaluate the five-factor structure of the SDQ in a population sample of 10,254 16–18 year-olds from the youth@hordaland study. Measurement invariance across gender was assessed using multigroup CFA. A modestly modified five-factor solution fitted the data acceptably, accounting for one cross loading and some local dependencies. Importantly, partial measurement non-invariance was identified, with differential item functioning in eight items, and higher correlations between emotional and conduct problems for boys compared to girls. Implications for use clinically and in research are discussed. PMID:27138259

Contributing factors to vehicle to vehicle crash frequency and severity under rainfall.

PubMed

Jung, Soyoung; Jang, Kitae; Yoon, Yoonjin; Kang, Sanghyeok

2014-09-01

This study combined vehicle to vehicle crash frequency and severity estimations to examine factor impacts on Wisconsin highway safety in rainy weather. Because of data deficiency, the real-time water film depth, the car-following distance, and the vertical curve grade were estimated with available data sources and a GIS analysis to capture rainy weather conditions at the crash location and time. Using a negative binomial regression for crash frequency estimation, the average annual daily traffic per lane, the interaction between the posted speed limit change and the existence of an off-ramp, and the interaction between the travel lane number change and the pavement surface material change were found to increase the likelihood of vehicle to vehicle crashes under rainfall. However, more average daily rainfall per month and a wider left shoulder were identified as factors that decrease the likelihood of vehicle to vehicle crashes. In the crash severity estimation using the multinomial logit model that outperformed the ordered logit model, the travel lane number, the interaction between the travel lane number and the slow grade, the deep water film, and the rear-end collision type were more likely to increase the likelihood of injury crashes under rainfall compared with crashes involving only property damage. As an exploratory data analysis, this study provides insight into potential strategies for rainy weather highway safety improvement, specifically, the following weather-sensitive strategies: road design and ITS implementation for drivers' safety awareness under rainfall. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

XRD and XAS structural study of CuAlO2 under high pressure.

PubMed

Pellicer-Porres, J; Segura, A; Ferrer-Roca, Ch; Polian, A; Munsch, P; Kim, D

2013-03-20

We present the results of x-ray diffraction and x-ray absorption spectroscopy experiments in CuAlO(2) under high pressure. We discuss the polarization dependence of the x-ray absorption near-edge structure at the Cu K-edge. XRD under high pressure evidences anisotropic compression, the a-axis being more compressible than the c-axis. EXAFS yields the copper-oxygen bond length, from which the only internal parameter of the delafossite structure is deduced. The combination of anisotropic compression and the internal parameter decrease results in a regularization of the AlO(6) octahedra. The anisotropic compression is related to the chemical trends observed in the lattice parameters when Al is substituted by other trivalent cations. Both experiments evidence the existence of an irreversible phase transition that clearly manifests at 35 ± 2 GPa. The structure of the high-pressure polymorph could not be determined, but it implies a change of the Cu environment, which remains anisotropic. Precursor effects are observed from the lowest pressures, which are possibly related to crystal breaking at a submicroscopic scale with partial reorientation of the crystallites.

XRD and XAS structural study of CuAlO2 under high pressure

NASA Astrophysics Data System (ADS)

Pellicer-Porres, J.; Segura, A.; Ferrer-Roca, Ch; Polian, A.; Munsch, P.; Kim, D.

2013-03-01

We present the results of x-ray diffraction and x-ray absorption spectroscopy experiments in CuAlO2 under high pressure. We discuss the polarization dependence of the x-ray absorption near-edge structure at the Cu K-edge. XRD under high pressure evidences anisotropic compression, the a-axis being more compressible than the c-axis. EXAFS yields the copper-oxygen bond length, from which the only internal parameter of the delafossite structure is deduced. The combination of anisotropic compression and the internal parameter decrease results in a regularization of the AlO6 octahedra. The anisotropic compression is related to the chemical trends observed in the lattice parameters when Al is substituted by other trivalent cations. Both experiments evidence the existence of an irreversible phase transition that clearly manifests at 35 ± 2 GPa. The structure of the high-pressure polymorph could not be determined, but it implies a change of the Cu environment, which remains anisotropic. Precursor effects are observed from the lowest pressures, which are possibly related to crystal breaking at a submicroscopic scale with partial reorientation of the crystallites.

Examining the Factor Structure of the MLQ Transactional and Transformational Leadership Dimensions in Nursing Context.

PubMed

Boamah, Sheila A; Tremblay, Paul

2018-05-01

The Multifactor Leadership Questionnaire (MLQ) is the most widely used instrument for assessing dimensions of leadership style; yet, most studies have failed to reproduce the original MLQ factor structure. The current study evaluates the dimensionality and nomological validity of Bass's transactional and transformational leadership model using the MLQ in a sample of registered nurses working in acute care hospitals in Canada. A combination of exploratory and confirmatory factor analyses were used to evaluate the hypothetical factor structure of the MLQ consisting of five transformational factors, and three transactional factors. Results suggest that the eight-factor solution displayed best fit indices; however, two transactional factors should be extracted due to high interscale correlations and lack of differential relationships with the two leadership variables. The findings support a scale refinement and the need for new theory concerning the five transformational leadership and contingent reward dimensions of the MLQ.

The G-factor as a tool to learn more about bone structure and function.

PubMed

Zerath, E

1999-07-01

In normal life on earth, the locomotor system is exposed to two types of stimulation: gravity (passive stimulation) and motion (active stimulation). Both permanently combine, and the interactions between locomotion and gravity induce an overall recruitment which is repeated daily and maintains the bone tissue structure within the range of constraints to which it is adapted. This range is one of the basic hypotheses underlying the mechanical concepts of bone structure control, and it has been considered as logical to assume that weightlessness of spaceflight should produce bone loss since astronauts are outside of the terrestrial gravitational field of forces, no longer relying on muscular work to change positions or move. But, thirty years after the first changes in phospho-calcium metabolism were observed in astronauts after spaceflight, current knowledge does not provide a full understanding of this pathogeny, and prove the G-factor is now considered as an essential component of the experimental tools available to study bone physiology. The study of the physiology of bone tissue usually consists in the investigation of its two fundamental roles, i.e. reservoir of inorganic elements (calcium, phosphorus, magnesium) and mechanical support for soft tissues. Together with the combined action of muscles, tendons, and ligaments, this support permits motion and locomotion. These two functions rely on a sophisticated bone tissue architecture, and on the adaptability of this structure, with modeling and remodeling processes, themselves associated with the coupled activity of specialized bone cell populations.