Thermodynamic interpretation of the scaling of the dynamics of supercooled liquids

The recently discovered scaling law for the relaxation times, tau=f(T,V^g), where T is temperature and V the specific volume, is derived by a revision of the entropy model of the glass transition dynamics originally proposed by Avramov [I. Avramov, J. Non-Cryst. Solids 262, 258 (2000).]. In this modification the entropy is calculated by an alternative route, while retaining the approximation that the heat capacity is constant with T and P. The resulting expression for the variation of the relaxation time with T and V is shown to accurately fit experimental data for several glass-forming liquids and polymers over an extended range encompassing the dynamic crossover. From this analysis, which is valid for any model in which the relaxation time is a function of the entropy. we find that the scaling exponent g can be identified with the Gruneisen constant.Comment: 24 pages, 7 figure

Focus on the Role of D-serine and D-amino Acid Oxidase in Amyotrophic Lateral Sclerosis/Motor Neuron Disease (ALS)

Highly pathogenic avian influenza (HPAI) H5N1 virus has been circulating in Vietnam since 2003, while outbreaks of HPAI H5N6 virus are more recent, having only been reported since 2014. Although the spatial distribution of H5N1 outbreaks and risk factors for virus occurrence have been extensively studied, there have been no comparative studies for H5N6. Data collected through active surveillance of Vietnamese live-bird markets (LBMs) between 2011 and 2015 were used to explore and compare the spatio-temporal distributions of H5N1- and H5N6-positive LBMs. Conditional autoregressive models were developed to quantify spatio-temporal associations between agro-ecological factors and the two HPAI strains using the same set of predictor variables. Unlike H5N1, which exhibited a strong north-south divide, with repeated occurrence in the extreme south of a cluster of high-risk provinces, H5N6 was homogeneously distributed throughout Vietnam. Similarly, different agro-ecological factors were associated with each strain. Sample collection in the months of January and February and higher average maximum temperature were associated with higher likelihood of H5N1 positive market-day status. The likelihood of market-days being positive for H5N6 increased with decreased river density, and with successive Rounds of data collection. This study highlights marked differences in spatial patterns and risk factors for H5N1 and H5N6 in Vietnam, suggesting the need for tailored surveillance and control approaches

Modelling and Simulation of Urban Mobile Agents for Analyzing Mixed Flows in Urban Pedestrian Space

Since the 1990s, complex systems research has been developing agent simulations to explain the phenomena observed in urban spaces. In recent years, agent-based modelling has often been employed to successfully simulate pedestrian behaviour. In such studies, explanations using pedestrian counter flow phases have appeared sporadically. Most state-of-the-art models, however, do not generally consider mobile agents other than pedestrians or counter flows in at least two directions. In this paper, we consider agents such as pedestrians, vehicles, wheelchairs, bicycles and so on in urban pedestrian space (UPS), which we call urban mobile agents (UMAs). The aim of this research is to develop a simulation platform to support urban simulation research. The models of rule-based UMAs that we have been developing are used to analyze the micro-meso behaviours of the mixed flows in UPS. The content of this class of agent includes the pedestrian agent as per the simplified agent simulation of pedestrian flow (sASPF) rules as well as the vehicle agent and bicycle agent in the UPS, including a wheelchair agent in the coming research. Using these models, we explore the following approaches: (a) theoretical analyses of phase transitions such as laminar flow formation or blockade of pedestrian counter flows, with clarification of the relationship between the degree of pedestrian global density and the bias of the diagonal stepping probability, which is the right or left selection probability of avoidance behaviour; (b) the implementation of obstacle avoidance rules in the sASPF pedestrian agent model, and their comparison with published evacuation experiment results, so as to evaluate the performance of the obstacle avoidance function; (c) the development of a vehicle agent model to simulate pedestrian-vehicle mixed flow at a crossroads assuming a disaster scenario; (d) the development of a bicycle agent model by extending sASPF rules; and (e) consideration of a conceptual framework for interaction fields representing heterogeneous agent mixed flows, including vehicle, bicycle, pedestrian and wheelchair agents

Bayesian Estimation-Based Pedestrian Tracking in Microcells

We consider a pedestrian tracking system where sensor nodes are placed only at specific points so that the monitoring region is divided into multiple smaller regions referred to as microcells. In the proposed pedestrian tracking system, sensor nodes composed of pairs of binary sensors can detect pedestrian arrival and departure events. In this paper, we focus on pedestrian tracking in microcells. First, we investigate actual pedestrian trajectories in a microcell on the basis of observations using video sequences, after which we prepare a pedestrian mobility model. Next, we propose a method for pedestrian tracking in microcells based on the developed pedestrian mobility model. In the proposed method, we extend the Bayesian estimation to account for time-series information to estimate the correspondence between pedestrian arrival and departure events. Through simulations, we show that the tracking success ratio of the proposed method is increased by 35.8% compared to a combinatorial optimization-based tracking method

High-Efficiency Sky Blue-To-Green Fluorescent Emitters Based on 3-Pyridinecarbonitrile Derivatives

The pyridinecarbonitrile derivative is well known as an acceptor unit in fluorescent materials. However, its use in thermally activated delayed fluorescent (TADF) emitters is very limited compared with its benzenecarbonitrile counterparts. Very recently, we developed a series of 4-pyridinecarbonitrile, so-called isonicotinonitrile derivatives, as a highly efficient sky blue-to-green TADF emitters realizing low-drive-voltage organic light-emitting devices (OLEDs). In this work, we contributed new design and development for three 3-pyridinecarbonitrile-based TADF emitters named 2AcNN, 2PXZNN, and 5PXZNN. Among these emitters, a sky blue emitter, 2AcNN, showed a maximum external quantum efficiency (ηext,max) of 12% with CIE (0.19, 0.36). While green emitters, 5PXZNN and 2PXZNN, realized highly efficient TADF OLEDs with a ηext,max of 16–20%. Introduction of electron-donor moiety into the 2-position of 3-pyridinecarbonitrile contributes a larger overlapping of frontier molecular orbitals (FMOs) and stronger intramolecular charge transfer (ICT) interaction generating efficient TADF emitters