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Pamela S Filby, Sundeep Rayat
Intramolecular cyclization of the heteroenyne-allene, 2-((biphenyl-2-ylimino)methyleneamino)benzonitrile 1 to phenanthridine-fused quinazoliniminium salt PQ in the presence of a Lewis acid at room temperature involves formation of two new bonds: a C-C bond and a C-N bond. In this article, density functional theory (B3LYP and M06-2X) was employed in conjunction with 6-311G* basis set to gain insights into the mechanism of this cyclization reaction. The solvent effects were considered using Polarizable Continuum Model with nitromethane as the solvent...
January 19, 2018: Journal of Organic Chemistry
Florence Volaire
Plant adaptation to drought has been extensively studied at many scales from ecology to molecular biology across a large range of model species. However, the conceptual frameworks underpinning the definition of plant strategies, and the terminology used across the different disciplines and scales are not analogous. 'Drought resistance' for instance refers to plant responses as different as the maintenance of growth and productivity in crops, to the survival and recovery in perennial woody or grassland species...
January 19, 2018: Global Change Biology
Anne Krayer, Catherine A Robinson, Rob Poole
Although the police play an important role for people with mental health problems in the community, little is known about joint working practices between mental health, social care and police services. There is potential for tensions and negative outcomes for people with mental health problems, in particular when the focus is on behaviours that could be interpreted as anti-social. This study explores perceptions about joint working between mental health, social care and police services with regard to anti-social behaviour...
January 18, 2018: Health & Social Care in the Community
Geneviève Jessiman-Perreault, Lynn McIntyre
Purpose: Household food insecurity is related to poor mental health. This study examines whether the level of household food insecurity is associated with a gradient in the risk of reporting six adverse mental health outcomes. This study further quantifies the mental health impact if severe food insecurity, the extreme of the risk continuum, were eliminated in Canada. Methods: Using a pooled sample of the Canadian Community Health Survey (N = 302,683), we examined the relationship between level of food insecurity, in adults 18-64 years, and reporting six adverse mental health outcomes...
December 2017: SSM—Population Health
Kimberly C Thomson, Martin Guhn, Chris G Richardson, Jean A Shoveller
Investigating the determinants of positive mental health, as opposed to focusing on mental illness, is a new research direction with important implications for population health promotion. Past research suggests that mental health develops in early childhood and that social factors including highest household educational attainment may play an important role. The current study examined the association between household educational attainment and adolescent self-reported positive mental health in a nationally representative Canadian sample using data from the 2011-12 Canadian Community Health Survey...
December 2017: SSM—Population Health
Christopher L Davies, Marina R Filip, Jay B Patel, Timothy W Crothers, Carla Verdi, Adam D Wright, Rebecca L Milot, Feliciano Giustino, Michael B Johnston, Laura M Herz
Photovoltaic devices based on metal halide perovskites are rapidly improving in efficiency. Once the Shockley-Queisser limit is reached, charge-carrier extraction will be limited only by radiative bimolecular recombination of electrons with holes. Yet, this fundamental process, and its link with material stoichiometry, is still poorly understood. Here we show that bimolecular charge-carrier recombination in methylammonium lead triiodide perovskite can be fully explained as the inverse process of absorption...
January 18, 2018: Nature Communications
Sarah Cotterill, Sarah Knowles, Anne-Marie Martindale, Rebecca Elvey, Susan Howard, Nia Coupe, Paul Wilson, Michael Spence
BACKGROUND: The Template for Intervention Description and Replication (TIDieR) checklist and guide was developed by an international team of experts to promote full and accurate description of trial interventions. It is now widely used in health research. The aim of this paper is to describe the experience of using TIDieR outside of trials, in a range of applied health research contexts, and make recommendations on its usefulness in such settings. MAIN BODY: We used the TIDieR template for intervention description in six applied health research projects...
January 18, 2018: BMC Medical Research Methodology
Shun Okushima, Toshihiro Kawakatsu
We perform a series of Monte Carlo simulations on an interface between a liquid crystal (LC) material in isotropic phase in its bulk and a surfactant membrane. These two objects are simulated using coarse-grained molecular models. We estimate physical properties of the membrane such as the interfacial tension and the bending rigidity, focusing on the anchoring effects of the membrane on the LC. According to our simulation results, when the strength of the homeotropic anchoring denoted by the anchoring parameter ξ is increased, the interfacial tension decreases and the bending rigidity first increases in ξ<ξ_{m}, and it then decreases in ξ_{m}<ξ...
November 2017: Physical Review. E
Stefano S Turzi
I propose a continuum theory for active nematic gels, defined as fluids or suspensions of orientable rodlike objects endowed with active dynamics, that is based on symmetry arguments and compatibility with thermodynamics. The starting point is our recent theory that models (passive) nematic liquid crystals as relaxing nematic elastomers. The interplay between viscoelastic response and active dynamics of the microscopic constituents is naturally taken into account. By contrast with standard theories, activity is not introduced as an additional term of the stress tensor, but it is added as an external remodeling force that competes with the passive relaxation dynamics and drags the system out of equilibrium...
November 2017: Physical Review. E
S Karthick, A K Sen
We provide improved understanding of acoustophoretic focusing of a dense suspension (volume fraction φ>10%) in a microchannel subjected to an acoustic standing wave using a proposed theoretical model and experiments. The model is based on the theory of interacting continua and utilizes a momentum transport equation for the mixture, continuity equation, and transport equation for the solid phase. The model demonstrates the interplay between acoustic radiation and shear-induced diffusion (SID) forces that is critical in the focusing of dense suspensions...
November 2017: Physical Review. E
Navdeep Rana, Pushpita Ghosh, Prasad Perlekar
We study spreading of a nonmotile bacteria colony on a hard agar plate by using agent-based and continuum models. We show that the spreading dynamics depends on the initial nutrient concentration, the motility, and the inherent demographic noise. Population fluctuations are inherent in an agent-based model, whereas for the continuum model we model them by using a stochastic Langevin equation. We show that the intrinsic population fluctuations coupled with nonlinear diffusivity lead to a transition from a diffusion limited aggregation type of morphology to an Eden-like morphology on decreasing the initial nutrient concentration...
November 2017: Physical Review. E
Walter Pötz
A single-cone finite-difference lattice scheme is developed for the (2+1)-dimensional Dirac equation in presence of general electromagnetic textures. The latter is represented on a (2+1)-dimensional staggered grid using a second-order-accurate finite difference scheme. A Peierls-Schwinger substitution to the wave function is used to introduce the electromagnetic (vector) potential into the Dirac equation. Thereby, the single-cone energy dispersion and gauge invariance are carried over from the continuum to the lattice formulation...
November 2017: Physical Review. E
Rituparno Mandal, Pranab Jyoti Bhuyan, Pinaki Chaudhuri, Madan Rao, Chandan Dasgupta
Is an active glass different from a conventional passive glass? To address this, we study the dynamics of a dense binary mixture of soft dumbbells, each subject to an active propulsion force and thermal fluctuations. This dense assembly shows dynamical arrest, first to a translational and then to a rotational glass, as one reduces temperature T or the self-propulsion force f. We monitor the dynamics along an iso-relaxation-time contour in the (T-f) plane. We find dramatic differences both in the fragility and in the nature of dynamical heterogeneity, which characterize the onset of glass formation-the activity-induced glass exhibits large swirls or vortices, whose scale is set by activity, and it appears to diverge as one approaches the glass transition...
October 2017: Physical Review. E
Kerstin Avila, Laura Steub, Thorsten Pöschel
Analogies between fluid flows and granular flows are useful because they pave the way for continuum treatments of granular media. However, in practice it is impossible to predict under what experimental conditions the dynamics of fluids and granulates are qualitatively similar. In the case of unsteadily driven systems no such analogy is known. For example, in a partially filled container subject to horizontal oscillations liquids slosh, whereas granular media of complex particles exhibit large-scale convection rolls...
October 2017: Physical Review. E
James Chen
A high order morphing continuum theory (MCT) is introduced to model highly compressible turbulence. The theory is formulated under the rigorous framework of rational continuum mechanics. A set of linear constitutive equations and balance laws are deduced and presented from the Coleman-Noll procedure and Onsager's reciprocal relations. The governing equations are then arranged in conservation form and solved through the finite volume method with a second-order Lax-Friedrichs scheme for shock preservation. A numerical example of transonic flow over a three-dimensional bump is presented using MCT and the finite volume method...
October 2017: Physical Review. E
David A Kessler, Stanislav Burov
A continuous approximation framework for general nonlinear stochastic as well as deterministic discrete maps is developed. For the stochastic map with uncorelated Gaussian noise, by successively applying the Itô lemma, we obtain a Langevin type of equation. Specifically, we show how nonlinear maps give rise to a Langevin description that involves multiplicative noise. The multiplicative nature of the noise induces an additional effective force, not present in the absence of noise. We further exploit the continuum description and provide an explicit formula for the stable distribution of the stochastic map and conditions for its existence...
October 2017: Physical Review. E
Xuejiao Liu, Benzhuo Lu
Potassium channels are much more permeable to potassium than sodium ions, although potassium ions are larger and both carry the same positive charge. This puzzle cannot be solved based on the traditional Poisson-Nernst-Planck (PNP) theory of electrodiffusion because the PNP model treats all ions as point charges, does not incorporate ion size information, and therefore cannot discriminate potassium from sodium ions. The PNP model can qualitatively capture some macroscopic properties of certain channel systems such as current-voltage characteristics, conductance rectification, and inverse membrane potential...
December 2017: Physical Review. E
Jinfu Liang, Yu An
We perform a computational fluid dynamics simulation of trivalent terbium [Tb(III)] ion line emissions from single-bubble sonoluminescence (SBSL). Our simulation includes dynamic boundary conditions as well as the effects of gas properties and quenching by species, such as nitrite ion (NO_{2}^{-}). Simulation results demonstrate that when the maximum temperature inside a dimly luminescing bubble is relatively low, emission peaks from excited Tb(III) ions are prominent within the emission spectra. As the maximum temperature of the bubble increases, emission peaks of Tb(III) ions fade away relative to the continuum background emission...
December 2017: Physical Review. E
Pierre Le Doussal
We obtain several exact results for universal distributions involving the maximum of the Airy_{2} process minus a parabola and plus a Brownian motion, with applications to the one-dimensional Kardar-Parisi-Zhang (KPZ) stochastic growth universality class. This allows one to obtain (i) the universal limit, for large time separation, of the two-time height correlation for droplet initial conditions, e.g., C_{∞}=lim_{t_{2}/t_{1}→+∞}h(t_{1})h(t_{2})[over ¯]^{c}/h(t_{1})^{2}[over ¯]^{c}, with C_{∞}≈0...
December 2017: Physical Review. E
R Kusdiantara, H Susanto
We consider the discrete Swift-Hohenberg equation with cubic and quintic nonlinearity, obtained from discretizing the spatial derivatives of the Swift-Hohenberg equation using central finite differences. We investigate the discretization effect on the bifurcation behavior, where we identify three regions of the coupling parameter, i.e., strong, weak, and intermediate coupling. Within the regions, the discrete Swift-Hohenberg equation behaves either similarly or differently from the continuum limit. In the intermediate coupling region, multiple Maxwell points can occur for the periodic solutions and may cause irregular snaking and isolas...
December 2017: Physical Review. E
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