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Theory of meaning

Li-Hui Mou, Qing-Yu Liu, Ting Zhang, Zi-Yu Li, Sheng-Gui He
Dinitrogen activation/fixation is one of the most important and challenging subjects in synthetic as well as theoretical chemistry. In this study, the adsorption reactions of N2 onto TaCn - ( n = 1-4) cluster anions have been investigated by means of mass spectrometry in conjunction with density functional theory calculations. Following the experimental results that only TaC4 - was observed to adsorb N2 , theoretical calculations predicted that TaC4 - reaction system (TaC4 - + N2 → TaC4 N2 - ) has a negligible barrier on the approach of N2 molecule while insurmountable barriers are located on the reaction pathways of TaC1-3 - /N2 reaction systems...
March 16, 2018: Journal of Physical Chemistry. A
P Alex Smith, Yaxin Wang, Ralph W Metcalfe, Luiz C Sampaio, Daniel L Timms, William E Cohn, O H Frazier
PURPOSE: A minimally invasive, partial-assist, intra-atrial blood pump has been proposed, which would unload the left ventricle with a flow path from the left atrium to the arterial system. Flow modulation is a common strategy for ensuring washout in the pump, but it can increase power consumption because it is typically achieved through motor-speed variation. However, if a pump's performance curve had the proper gradient, flow modulation could be realized passively. To achieve this goal, we propose a pump performance operating curve as an alternative to the more standard operating point...
March 2018: International Journal of Artificial Organs
Shaun K McGovern, Audrey L Blewer, Andrew Murray, Marion Leary, Benjamin S Abella, Raina M Merchant
STUDY A: im Recent investigations have suggested that CPR training rates are low within the U.S and barriers to CPR training are poorly understood. Social media holds great potential for large scale capture of the public's CPR training experiences and may illuminate barriers to CPR training. While studies have examined Twitter data for behaviors associated with cardiovascular health, no investigation has evaluated Twitter data to understand public perception of CPR training. We characterized Tweet content about CPR training and associated sentiment to better understand barriers associated with CPR training...
March 12, 2018: Resuscitation
Rami Benbenishty, Ron Avi Astor, Ilan Roziner
OBJECTIVES: To assess the between-school variation in suicide ideation and to estimate the contribution of school-level attributes, student-level characteristics, and 2 cross-level interactions (school by student) to student suicide ideation. STUDY DESIGN: A secondary analysis of the California Healthy Kids Survey in 2 large and representative samples of California high schools and students: 2009-2011 and 2011-2013. This is a population sample of all public high school students (grades 9 and 11) in California...
March 7, 2018: Journal of Pediatrics
C E Willis, S Reid, C Elliott, M Rosenberg, A Nyquist, R Jahnsen, S Girdler
BACKGROUND: The need to identify strategies that facilitate involvement in physical activity for children and youth with disabilities is recognised as an urgent priority. This study aimed to describe the association between context, mechanisms and outcome(s) of a participation-focused physical activity intervention to understand what works, in what conditions, and how. METHODS: This study was designed as a realist evaluation. Participant recruitment occurred through purposive and theoretical sampling of children and parents participating in the Local Environment Model intervention at Beitostolen Healthsports Centre in Norway...
March 15, 2018: BMC Pediatrics
Kazuhiro Takemura, Nobuyuki Matubayasi, Akio Kitao
To aid the evaluation of protein-protein complex model structures generated by protein docking prediction (decoys), we previously developed a method to calculate the binding free energies for complexes. The method combines a short (2 ns) all-atom molecular dynamics simulation with explicit solvent and solution theory in the energy representation (ER). We showed that this method successfully selected structures similar to the native complex structure (near-native decoys) as the lowest binding free energy structures...
March 14, 2018: Journal of Chemical Physics
Trung Hai Nguyen, David D L Minh
Implicit ligand theory enables noncovalent binding free energies to be calculated based on an exponential average of the binding potential of mean force (BPMF)-the binding free energy between a flexible ligand and rigid receptor-over a precomputed ensemble of receptor configurations. In the original formalism, receptor configurations were drawn from or reweighted to the apo ensemble. Here we show that BPMFs averaged over a holo ensemble yield binding free energies relative to the reference ligand that specifies the ensemble...
March 14, 2018: Journal of Chemical Physics
Yannick J Franzke, Nils Middendorf, Florian Weigend
We present an efficient algorithm for one- and two-component analytical energy gradients with respect to nuclear displacements in the exact two-component decoupling approach to the one-electron Dirac equation (X2C). Our approach is a generalization of the spin-free ansatz by Cheng and Gauss [J. Chem. Phys. 135, 084114 (2011)], where the perturbed one-electron Hamiltonian is calculated by solving a first-order response equation. Computational costs are drastically reduced by applying the diagonal local approximation to the unitary decoupling transformation (DLU) [D...
March 14, 2018: Journal of Chemical Physics
Giovanni Di Liberto, Riccardo Conte, Michele Ceotto
We present an investigation of vibrational features in water clusters performed by means of our recently established divide-and-conquer semiclassical approach [M. Ceotto, G. Di Liberto, and R. Conte, Phys. Rev. Lett. 119, 010401 (2017)]. This technique allows us to simulate quantum vibrational spectra of high-dimensional systems starting from full-dimensional classical trajectories and projection of the semiclassical propagator onto a set of lower dimensional subspaces. The potential energy surface employed is a many-body representation up to three-body terms, in which monomers and two-body interactions are described by the high level Wang-Huang-Braams-Bowman (WHBB) water potential, while, for three-body interactions, calculations adopt a fast permutationally invariant ab initio surface at the same level of theory of the WHBB 3-body potential...
March 14, 2018: Journal of Chemical Physics
Daniel Stopper, Alice L Thorneywork, Roel P A Dullens, Roland Roth
Using dynamical density functional theory (DDFT), we theoretically study Brownian self-diffusion and structural relaxation of hard disks and compare to experimental results on quasi two-dimensional colloidal hard spheres. To this end, we calculate the self-van Hove correlation function and distinct van Hove correlation function by extending a recently proposed DDFT-approach for three-dimensional systems to two dimensions. We find that the theoretical results for both self-part and distinct part of the van Hove function are in very good quantitative agreement with the experiments up to relatively high fluid packing fractions of roughly 0...
March 14, 2018: Journal of Chemical Physics
Chao Wang, Zhi-Yi Hu, Heng Zhao, Wenbei Yu, Sijia Wu, Jing Liu, Lihua Chen, Yu Li, Bao-Lian Su
We report three types of conducting polymers (CPs), polyaniline (PANI), polypyrrole (PPY) and poly (3,4-ethylenedioxythiophene) (PEDOT) to modify the surface of the CdS nanorods to probe their photocorrosion inhibition and photocatalytic hydrogen production. Various characterizations, such as high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and density function theory (DFT) calculations have been conducted to reveal the intrinsic structure of the as-constructed CPs@CdS (@ means CPs at the surface of CdS) core-shell nanorods...
March 6, 2018: Journal of Colloid and Interface Science
Christopher Ebsch, Robert Rosenbaum
Understanding the relationship between external stimuli and the spiking activity of cortical populations is a central problem in neuroscience. Dense recurrent connectivity in local cortical circuits can lead to counterintuitive response properties, raising the question of whether there are simple arithmetical rules for relating circuits' connectivity structure to their response properties. One such arithmetic is provided by the mean field theory of balanced networks, which is derived in a limit where excitatory and inhibitory synaptic currents precisely balance on average...
March 15, 2018: PLoS Computational Biology
Yaniv Efrati
BACKGROUND: Adolescent compulsive sexual behavior (CSB), and its associations with other personality predispositions (attachment orientations, temperament), gender, religiosity, and psychopathological tendencies. Five alternative empirical models were examined, all based on current theory and research on CSB. METHODS: The sample include 311 high-school adolescents (184 boys, 127 girls) ranging in age from 16 to 18 (M  = 16.94, SD  = .65) and enrolled in the eleventh (43...
March 15, 2018: Journal of Sex & Marital Therapy
Mark G Alford, Kamal Pangeni, Andreas Windisch
It is generally believed that when Cooper pairing occurs between two different species of fermions, their Fermi surfaces become locked together so that the resultant state remains "neutral," with equal number densities of the two species, even when subjected to a chemical potential that couples to the difference in number densities. This belief is based on mean-field calculations in models with a zero-range interaction, where the anomalous self-energy is independent of energy and momentum. Following up on an early report of a deviation from neutrality in a Dyson-Schwinger calculation of color-flavor-locked quark matter, we investigate the neutrality of a two-species condensate using a Yukawa model which has a finite-range interaction...
February 23, 2018: Physical Review Letters
Milad Rayka, Mohammad Goli, Shant Shahbazian
A set of effective electronic-only Kohn-Sham (EKS) equations are derived for the muonic molecules (containing a positively charged muon), which are completely equivalent to the coupled electronic-muonic Kohn-Sham equations derived previously within the framework of the nuclear-electronic orbital density functional theory (NEO-DFT). The EKS equations contain effective non-coulombic external potentials depending on parameters describing the muon's vibration, which are optimized during the solution of the EKS equations making the muon's KS orbital reproducible...
March 15, 2018: Physical Chemistry Chemical Physics: PCCP
T V Sachin Krishnan, Kento Yasuda, Ryuichi Okamoto, Shigeyuki Komura
We discuss thermal and active fluctuations of a compressible bilayer vesicle by using the results of hydrodynamic theory for vesicles. Coupled Langevin equations for the membrane deformation and the density fields are employed to calculate the power spectral density matrix of membrane fluctuations. Thermal contribution is obtained by means of the fluctuation dissipation theorem, whereas active contribution is calculated from exponentially decaying time correlation functions of active random forces. We obtain the total power spectral density as a sum of thermal and active contributions...
March 15, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Julian Cespedes-Guevara, Tuomas Eerola
Basic Emotion theory has had a tremendous influence on the affective sciences, including music psychology, where most researchers have assumed that music expressivity is constrained to a limited set of basic emotions. Several scholars suggested that these constrains to musical expressivity are explained by the existence of a shared acoustic code to the expression of emotions in music and speech prosody. In this article we advocate for a shift from this focus on basic emotions to a constructionist account. This approach proposes that the phenomenon of perception of emotions in music arises from the interaction of music's ability to express core affects and the influence of top-down and contextual information in the listener's mind...
2018: Frontiers in Psychology
Melissa H Bellin, Angelica Newsome, Cassie Lewis-Land, Joan Kub, Shawna S Mudd, Rachel Margolis, Arlene M Butz
INTRODUCTION: Low-income caregiver perspectives on asthma management are understudied but may illuminate strategies to improve care delivery and child outcomes. METHOD: Purposive sampling methods were used to recruit 15 caregivers of children with frequent asthma emergency department visits. Interviews explored how poverty and stress affect asthma management. Grounded theory coding techniques were used to analyze the data. RESULTS: Participants were the biological mother (100%) and were poor (75% had mean annual income ≤ $30,000)...
March 12, 2018: Journal of Pediatric Health Care
Kamylla Santos da Cunha, Selma Regina de Andrade, Alacoque Lorenzini Erdmann
OBJECTIVE: to understand the meaning of the university management performed by nurses managers of the nursing undergraduate course of a public university. METHOD: this is a qualitative research, based on the grounded theory. Data collection took place between May and September 2016, with open interviews, in the scenario of a federal public university. The technique of constant comparative analysis of the data was followed, obtaining a theoretical sample with 19 nurses, in two sample groups...
March 8, 2018: Revista Latino-americana de Enfermagem
Wanderlei Abadio de Oliveira, Jorge Luiz da Silva, Iara Falleiros Braga, Claudio Romualdo, Simona Carla Silvia Caravita, Marta Angélica Iossi Silva
This study unveils the meaning attributed by students to bullying and contributes to the approach of student health. The objective was to identify the dimensions of the conceptions of students regarding bullying. A total of 55 students from 11 public schools participated by answering semi-structured interviews. Dimensional analysis was used to treat data and a matrix was constructed with the dimensions identified. The Grounded Theory was adopted as the methodological and theoretical framework. The adolescents were aware of the main dimensions of bullying but explained it descriptively and from individual perspectives...
March 2018: Ciência & Saúde Coletiva
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