Showing papers by "University of North Texas published in 2013"

The high-throughput highway to computational materials design

Abstract: High-throughput computational materials design is an emerging area of materials science. By combining advanced thermodynamic and electronic-structure methods with intelligent data mining and database construction, and exploiting the power of current supercomputer architectures, scientists generate, manage and analyse enormous data repositories for the discovery of novel materials. In this Review we provide a current snapshot of this rapidly evolving field, and highlight the challenges and opportunities that lie ahead.

A community-driven global reconstruction of human metabolism

Abstract: Multiple models of human metabolism have been reconstructed, but each represents only a subset of our knowledge. Here we describe Recon 2, a community-driven, consensus 'metabolic reconstruction', which is the most comprehensive representation of human metabolism that is applicable to computational modeling. Compared with its predecessors, the reconstruction has improved topological and functional features, including ~2× more reactions and ~1.7× more unique metabolites. Using Recon 2 we predicted changes in metabolite biomarkers for 49 inborn errors of metabolism with 77% accuracy when compared to experimental data. Mapping metabolomic data and drug information onto Recon 2 demonstrates its potential for integrating and analyzing diverse data types. Using protein expression data, we automatically generated a compendium of 65 cell type–specific models, providing a basis for manual curation or investigation of cell-specific metabolic properties. Recon 2 will facilitate many future biomedical studies and is freely available at http://humanmetabolism.org/.

Cultural humility: measuring openness to culturally diverse clients.

Abstract: Building on recent theory stressing multicultural orientation, as well as the development of virtues and dispositions associated with multicultural values, we introduce the construct of cultural humility, defined as having an interpersonal stance that is other-oriented rather than self-focused, characterized by respect and lack of superiority toward an individual's cultural background and experience. In 4 studies, we provide evidence for the estimated reliability and construct validity of a client-rated measure of a therapist's cultural humility, and we demonstrate that client perceptions of their therapist's cultural humility are positively associated with developing a strong working alliance. Furthermore, client perceptions of their therapist's cultural humility were positively associated with improvement in therapy, and this relationship was mediated by a strong working alliance. We consider implications for research, practice, and training.

A study of mobile user engagement (MoEN)

Abstract: The growth of mobile technology mediated environments is accelerated by its accessibility and easy use tools, such as smartphones and tablets. User friendly and intuitive features drive user value and satisfaction. These features motivate and drive further mobile user engagement. Smartphones, for example, allow users to control when, where, and how they engage in chosen activities that serve their needs, saving time, completing a task (utilitarian), entertain them (hedonic), or connect with others (social). Few studies have examined why and how mobile users are continually engaging mobile activities. Focusing on mobile engagement which has not previously been explored, this study investigates, proposes, and tests a mobile user engagement (MoEN) model to explain mobile user engagement intention through user's motivations, perceived value and satisfaction. Findings indicate that mobile users' engagement motivations do influence perceived value, satisfaction and mobile engagement intention. Research introduces the concept of mobile user engagement (MoEN).Research utilizes the cognitive-affective-conative stage framework.Research framework helps to understand mobile user mobile engagement motivations.Empirical results highlight the importance of mobile user engagement behavior.

Improving efficiency and accuracy in multilingual entity extraction

Abstract: There has recently been an increased interest in named entity recognition and disambiguation systems at major conferences such as WWW, SIGIR, ACL, KDD, etc. However, most work has focused on algorithms and evaluations, leaving little space for implementation details. In this paper, we discuss some implementation and data processing challenges we encountered while developing a new multilingual version of DBpedia Spotlight that is faster, more accurate and easier to configure. We compare our solution to the previous system, considering time performance, space requirements and accuracy in the context of the Dutch and English languages. Additionally, we report results for 9 additional languages among the largest Wikipedias. Finally, we present challenges and experiences to foment the discussion with other developers interested in recognition and disambiguation of entities in natural language text.

Edge-selectively sulfurized graphene nanoplatelets as efficient metal-free electrocatalysts for oxygen reduction reaction: the electron spin effect.

Abstract: To replace precious platinum (Pt)-based electrocatalysts for cathodic oxygen reduction reaction (ORR), edge-selectively sulfurized graphene nanoplatelets (SGnP) are synthesized as efficient metal-free electrocatalysts simply by ball-milling pristine graphite in the presence of sulfur (S8 ). The resultant SGnPs exhibit remarkable electrocatalytic activity toward ORR with better tolerance to methanol crossover/CO poisoning effects and longer-term stability than those of pristine graphite and commercial Pt/C electrocatalysts. Edge-Selectively Sulfurized Graphene Nanoplatelets as Efficient Metal-Free Electrocatalysts for Oxygen Reduction Reaction: The Electron Spin Effect.

Effects of reputation and website quality on online consumers' emotion, perceived risk and purchase intention: Based on the stimulus‐organism‐response model

Abstract: Purpose – This research extends Mehrabian and Russell's Stimulus‐Organism‐Response model to include both external (i.e. reputation) and internal source of information (i.e. website quality) as stimuli which affect consumers' response systems. The purpose of this paper is to test a more comprehensive model consisting of reputation and website quality (stimuli), cognition and emotion (organism) and purchase intention (response).Design/methodology/approach – In total, 219 usable questionnaires were obtained at a large Midwestern university through online survey. Structural equation modeling (SEM) was employed for data analyses.Findings – Reputation had a significant positive effect on consumers' emotion and significant negative effect on perceived risk. All four website quality dimensions had significant negative effects on perceived risk and significant positive effects on emotion, except for customer service. Perceived risk had a significant negative effect on consumers' emotion, and both perceived risk an...

Halogen Bonds: Benchmarks and Theoretical Analysis

Abstract: We carried out an extensive survey of wave function and DFT methods to test their accuracy on geometries and dissociation energies of halogen bonds (XB). For that purpose, we built two benchmark sets (XB18 and XB51). Between the DFT methods, it was found that functionals with high exact exchange or long-range corrections were suitable for these dimers, especially M06-2X, ωB97XD, and double hybrids. Dispersion corrections tend to be detrimental, in spite of the fact that XB is considered a noncovalent interaction. Wave function techniques require heavy correlated methods (i.e., CCSD(T)) or parametrized ones (SCS-MP2 or SCS(MI)MP2). Heavy basis sets are needed to obtain high accuracy, such as aVQZ or aVTZ+CP, and ideally a CBS extrapolation. Relativistic ECPs are also important, even for the bromine based dimers. In addition, we explored some XB with new theoretical tools, the NCI (“Non-Covalent Interactions”) method and the NOFF (“Natural Orbital Fukui Functions”).

Intrinsic electrical transport properties of monolayer silicene and MoS 2 from first principles

Abstract: Article on intrinsic electrical transport properties of monolayer silicene and MoS₂ from first principles.

Hispanic Mortality Paradox: A Systematic Review and Meta-Analysis of the Longitudinal Literature

Abstract: To investigate the possibility of a Hispanic mortality advantage, we conducted a systematic review and meta-analysis of the published longitudinal literature reporting Hispanic individuals’ mortality from any cause compared with any other race/ethnicity. We searched MEDLINE, PubMed, EMBASE, HealthSTAR, and PsycINFO for published literature from January 1990 to July 2010.Across 58 studies (4 615 747 participants), Hispanic populations had a 17.5% lower risk of mortality compared with other racial groups (odds ratio = 0.825; P < .001; 95% confidence interval = 0.75, 0.91). The difference in mortality risk was greater among older populations and varied by preexisting health conditions, with effects apparent for initially healthy samples and those with cardiovascular diseases. The results also differed by racial group: Hispanics had lower overall risk of mortality than did non-Hispanic Whites and non-Hispanic Blacks, but overall higher risk of mortality than did Asian Americans.These findings provided strong ...

Facile, scalable synthesis of edge-halogenated graphene nanoplatelets as efficient metal-free eletrocatalysts for oxygen reduction reaction

Abstract: A series of edge-selectively halogenated (X 5 Cl, Br, I) graphene nanoplatelets (XGnPs 5 ClGnP, BrGnP, IGnP) were prepared simply by ball-milling graphite in the presence of Cl2 ,B r 2 and I2, respectively. High BET surface areas of 471, 579 and 662 m 2 /g were observed for ClGnP, BrGnP and IGnP, respectively, indicating a significant extent of delamination during the ball-milling and subsequent workup processes. The newly-developed XGnPs can be well dispersed in various solvents, and hence are solution processable. Furthermore, XGnPs showed remarkable electrocatalytic activities toward oxygen reduction reaction (ORR) with a high selectivity, good tolerance to methanol crossover/CO poisoning effects, and excellent long-term cycle stability. First-principle density-functional calculations revealed that halogenated graphene edges could provide decent adsorption sites for oxygen molecules, in a good agreement with the experimental observations.

Temporal-Spatial Interaction between Reactive Oxygen Species and Abscisic Acid Regulates Rapid Systemic Acclimation in Plants

Abstract: Being sessile organisms, plants evolved sophisticated acclimation mechanisms to cope with abiotic challenges in their environment. These are activated at the initial site of exposure to stress, as well as in systemic tissues that have not been subjected to stress (termed systemic acquired acclimation [SAA]). Although SAA is thought to play a key role in plant survival during stress, little is known about the signaling mechanisms underlying it. Here, we report that SAA in plants requires at least two different signals: an autopropagating wave of reactive oxygen species (ROS) that rapidly spreads from the initial site of exposure to the entire plant and a stress-specific signal that conveys abiotic stress specificity. We further demonstrate that SAA is stress specific and that a temporal–spatial interaction between ROS and abscisic acid regulates rapid SAA to heat stress in plants. In addition, we demonstrate that the rapid ROS signal is associated with the propagation of electric signals in Arabidopsis thaliana. Our findings unravel some of the basic signaling mechanisms underlying SAA in plants and reveal that signaling events and transcriptome and metabolome reprogramming of systemic tissues in response to abiotic stress occur at a much faster rate than previously envisioned.

Long-distance communication and signal amplification in systemic acquired resistance

Abstract: Systemic acquired resistance (SAR) is an inducible defense mechanism in plants that confers enhanced resistance against a variety of pathogens. SAR is activated in the uninfected systemic (distal) organs in response to a prior (primary) infection elsewhere in the plant. SAR is associated with the activation of salicylic acid (SA) signaling and the priming of defense responses for robust activation in response to subsequent infections. The activation of SAR requires communication by the primary infected tissues with the distal organs. The vasculature functions as a conduit for the translocation of factors that facilitate long-distance intra-plant communication. In recent years, several metabolites putatively involved in long-distance signaling have been identified. These include the methyl ester of SA (MeSA), the abietane diterpenoid dehydroabietinal (DA), the dicarboxylic acid azelaic acid (AzA), and a glycerol-3-phosphate (G3P)-dependent factor. Long-distance signaling by some of these metabolites also requires the lipid-transfer protein DIR1 (DEFECTIVE IN INDUCED RESISTANCE 1). The relative contribution of these factors in long-distance signaling is likely influenced by environmental conditions, for example light. In the systemic leaves, the AGD2-LIKE DEFENSE RESPONSE PROTEIN1 (ALD1)-dependent production of the lysine catabolite pipecolic acid (Pip), FLAVIN-DEPENDENT MONOOXYGENASE1 (FMO1) signaling, as well as SA synthesis and downstream signaling are required for the activation of SAR. This review summarizes the involvement and interaction between long-distance SAR signals and details the recently discovered role of Pip in defense amplification and priming that allows plants to acquire immunity at the systemic level. Recent advances in SA signaling and perception are also highlighted.

Antecedents of organizational knowledge sharing: a meta‐analysis and critique

Abstract: Purpose – Knowledge is the most important component of sustainable organizational growth and economic performance. This meta‐analysis aims to summarize the determinants of individuals' knowledge sharing (KS) intentions and behaviors in organizations.Design/methodology/approach – The authors organize the knowledge sharing antecedents investigated in 46 studies (n≈10,487, median n=172) into three categories, i.e. knowledge sharer intention and attitude (four variables); rewards for KS (three variables); and organizational culture (nine variables).Findings – Variables in all three antecedent categories positively contribute to KS intentions and behaviors; high between‐study variability exists, and the fail‐safe n statistic suggests the observed effects are robust against a “file drawer” (missing study) bias. Moderator results suggest that motivating KS is easier in collectivist, as opposed to individualist, cultures.Research limitations/implications – In most of the studies included in this meta‐analysis, pa...

Hyperbolic metamaterials: new physics behind a classical problem

Abstract: Hyperbolic materials enable numerous surprising applications that include far-field subwavelength imaging, nanolithography, and emission engineering. The wavevector of a plane wave in these media follows the surface of a hyperboloid in contrast to an ellipsoid for conventional anisotropic dielectric. The consequences of hyperbolic dispersion were first studied in the 50’s pertaining to the problems of electromagnetic wave propagation in the Earth’s ionosphere and in the stratified artificial materials of transmission lines. Recent years have brought explosive growth in optics and photonics of hyperbolic media based on metamaterials across the optical spectrum. Here we summarize earlier theories in the Clemmow’s prescription for transformation of the electromagnetic field in hyperbolic media and provide a review of recent developments in this active research area.

Understanding the Results of Multiple Linear Regression: Beyond Standardized Regression Coefficients

Abstract: Multiple linear regression (MLR) remains a mainstay analysis in organizational research, yet intercorrelations between predictors (multicollinearity) undermine the interpretation of MLR weights in terms of predictor contributions to the criterion. Alternative indices include validity coefficients, structure coefficients, product measures, relative weights, all-possible-subsets regression, dominance weights, and commonality coefficients. This article reviews these indices, and uniquely, it offers freely available software that (a) computes and compares all of these indices with one another, (b) computes associated bootstrapped confidence intervals, and (c) does so for any number of predictors so long as the correlation matrix is positive definite. Other available software is limited in all of these respects. We invite researchers to use this software to increase their insights when applying MLR to a data set. Avenues for future research and application are discussed.

Non-state actors in civil wars: A new dataset

Abstract: This paper introduces the Non-State Actors in Armed Conflict Dataset (NSA), which contains detailed information on the state–rebel group dyads included in the Uppsala Conflict Data Project Dyadic Dataset. Existing quantitative studies generally focus on characteristics of countries and conflicts to examine the duration, severity, outcome and recurrence of civil wars, in ways that often ignore the actors in civil wars. The NSA data provides additional information on the organizations involved in conflict dynamics. We describe the structure of the NSA data and the variables included, provide descriptive statistics of the indicators, and discuss areas for future research on non-state actors to enhance our understanding of conflict processes.

Improvement of Quality in Publication of Experimental Thermophysical Property Data: Challenges, Assessment Tools, Global Implementation, and Online Support

Abstract: This article describes a 10-year cooperative effort between the U.S. National Institute of Standards and Technology (NIST) and five major journals in the field of thermophysical and thermochemical properties to improve the quality of published reports of experimental data. The journals are Journal of Chemical and Engineering Data, The Journal of Chemical Thermodynamics, Fluid Phase Equilibria, Thermochimica Acta, and International Journal of Thermophysics. The history of this unique cooperation is outlined, together with an overview of software tools and procedures that have been developed and implemented to aid authors, editors, and reviewers at all stages of the publication process, including experiment

Three-dimensional metal-graphene-nanotube multifunctional hybrid materials.

Abstract: Graphene was grown directly on porous nickel films, followed by the growth of controlled lengths of vertical carbon nanotube (CNT) forests that seamlessly emanate from the graphene surface. The metal–graphene–CNT structure is used to directly fabricate field-emitter devices and double-layer capacitors. The three-dimensional nanostructured hybrid materials, with better interfacial contacts and volume utilization, can stimulate the development of several energy-efficient technologies.

Multimodal Sentiment Analysis of Spanish Online Videos

Abstract: Using multimodal sentiment analysis, the presented method integrates linguistic, audio, and visual features to identify sentiment in online videos. In particular, experiments focus on a new dataset consisting of Spanish videos collected from YouTube that are annotated for sentiment polarity.

Solubility of Carvedilol in Ethanol + Propylene Glycol Mixtures at Various Temperatures

Abstract: Article on the solubility of carvedilol in ethanol and propylene glycol mixtures at various temperatures.

A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys

Abstract: We present an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure the characteristic spectral index, Γ, of a power-law energy distribution, over an energy range of 2–10 keV, for X-ray selected, broad-lined radio-quiet active galactic nuclei (AGN) up to z ∼ 2 in Cosmic Evolution Survey (COSMOS) and Extended Chandra Deep Field South (E-CDF-S). We test the previously reported dependence between Γ and black hole mass, full width at half-maximum (FWHM) and Eddington ratio using a sample of AGN covering a broad range in these parameters based on both the Mg II and Hα emission lines with the later afforded by recent near-infrared spectroscopic observations using Subaru/Fibre Multi Object Spectrograph. We calculate the Eddington ratios, λ_(Edd), for sources where a bolometric luminosity (L_(Bol)) has been presented in the literature, based on spectral energy distribution fitting, or, for sources where these data do not exist, we calculate L_(Bol) using a bolometric correction to the X-ray luminosity, derived from a relationship between the bolometric correction and L_X/L_(3000). From a sample of 69 X-ray bright sources (>250 counts), where Γ can be measured with greatest precision, with an estimate of L_(Bol), we find a statistically significant correlation between Γ and λ_(Edd), which is highly significant with a chance probability of 6.59× 10^(−8). A statistically significant correlation between Γ and the FWHM of the optical lines is confirmed, but at lower significance than with λ_(Edd) indicating that λ_(Edd) is the key parameter driving conditions in the corona. Linear regression analysis reveals that Γ = (0.32 ± 0.05) log_(10)λ_(Edd) + (2.27 ± 0.06) and Γ = (−0.69 ± 0.11) log_(10)(FWHM/km s^(−1)) + (4.44 ± 0.42). Our results on Γ–λ_(Edd) are in very good agreement with previous results. While the Γ–λ_(Edd) relationship means that X-ray spectroscopy may be used to estimate black hole accretion rate, considerable dispersion in the correlation does not make this viable for single sources, however could be valuable for large X-ray spectral samples, such as those to be produced by eROSITA.

The neural signatures of distinct psychopathic traits

Abstract: Recent studies suggest that psychopathy may be associated with dysfunction in the neural circuitry supporting both threat- and reward-related processes. However, these studies have involved small samples and often focused on extreme groups. Thus, it is unclear to what extent current findings may generalize to psychopathic traits in the general population. Furthermore, no studies have systematically and simultaneously assessed associations between distinct psychopathy facets and both threat- and reward-related brain function in the same sample of participants. Here, we examined the relationship between threat-related amygdala reactivity and reward-related ventral striatum (VS) reactivity and variation in four facets of self-reported psychopathy in a sample of 200 young adults. Path models indicated that amygdala reactivity to fearful facial expressions is negatively associated with the interpersonal facet of psychopathy, whereas amygdala reactivity to angry facial expressions is positively associated with the lifestyle facet. Furthermore, these models revealed that differential VS reactivity to positive versus negative feedback is negatively associated with the lifestyle facet. There was suggestive evidence for gender-specific patterns of association between brain function and psychopathy facets. Our findings are the first to document differential associations between both threat- and reward-related neural processes and distinct facets of psychopathy and thus provide a more comprehensive picture of the pattern of neural vulnerabilities that may predispose to maladaptive outcomes associated with psychopathy.