A new algorithm for extended nonequilibrium molecular dynamics simulations of mixed flow

In this work, we develop a new algorithm for nonequilibrium molecular dynamics of fluids under planar mixed flow, a linear combination of planar elongational flow and planar Couette flow. To date, the only way of simulating mixed flow using nonequilibrium molecular dynamics techniques was to impose onto the simulation box irreversible transformations. This would bring the simulation to an end as soon as the minimum lattice space requirements were violated. In practical terms, this meant repeating the short simulations to improve statistics and extending the box dimensions to increase the total simulation time. Our method, similar to what has already been done for pure elongational flow, allows a cuboid box to deform in time following the streamlines of the mixed flow and, after a period of time determined by the elongational field, to be mapped back and recover its initial shape. No discontinuity in physical properties is present during the mapping and the simulation can, in this way, be extended indefinitely. We also show that the most general form of mixed flow, in which the angle between the expanding (or contracting) direction and the velocity gradient axis varies, can be cast in a so-called canonical form, in which the angle assumes values that are multiples of π (when a mixed flow exists), by an appropriate choice of the field parameters

Temperature dependence of magnetic anisotropy and domain wall tuning in BaTiO₃(111)/CoFeB multiferroics

Artificial multiferroics consist of two types of ferroic materials, typically a ferroelectric and a ferromagnet, often coupled interfacially by magnetostriction induced by the lattice elongations in the ferroelectric. In BaTiO3, the magnitude of strain induced by these elongations is heavily temperature dependent, varying greatly between each of the polar crystal phases and exerting a huge influence over the properties of a coupled magnetic film. Here, we demonstrate that temperature and, thus, strain are effective means of controlling the magnetic anisotropy in BaTiO3(111)/CoFeB heterostructures. We investigate the three polar phases of BaTiO3: tetragonal (T) at room temperature, orthorhombic (O) below 280 K, and rhombohedral (R) below 190 K across a total range of 77–420 K. We find two distinct responses: a step-like change in the anisotropy across the low-temperature phase transitions and a sharp high-temperature reduction around the ferroelectric Curie temperature, measured from hard axis hysteresis loops. Using our measurements of this anisotropy strength, we are then able to show by micromagnetic simulation the behavior of all possible magnetic domain wall states and determine their scaling as a function of temperature. The most significant changes occur in the head-to-head domain wall states, with a maximum change of 210 nm predicted across the entire range, effectively doubling the size of the domain wall as compared to room temperature. Notably, similar changes are seen for both high and low temperatures, which suggests different routes for potential control of magnetic anisotropy and elastically pinned magnetic domain walls

Effect of simplicity and attractiveness on route selection for different journey types

This study investigated the effects of six attributes, associated with simplicity or attractiveness, on route preference for three pedestrian journey types (everyday, leisure and tourist). Using stated choice preference experiments with computer generated scenes, participants were asked to choose one of a pair of routes showing either two levels of the same attribute (experiment 1) or different attributes (experiment 2). Contrary to predictions, vegetation was the most influential for both everyday and leisure journeys, and land use ranked much lower than expected in both cases. Turns ranked higher than decision points for everyday journeys as predicted, but the positions of both were lowered by initially unranked attributes. As anticipated, points of interest were most important for tourist trips, with the initially unranked attributes having less influence. This is the first time so many attributes have been compared directly, providing new information about the importance of the attributes for different journeys. © 2014 Springer International Publishing

Multivariate extreme value modelling of sea conditions around the coast of England

It is widely recognised that coastal flood events can arise from combinations of extreme waves and sea levels. For flood risk analysis and the design of coastal structures it is therefore necessary to assess the joint probability of the occurrence of these variables. Traditional methods have involved the application of joint probability contours, defined in terms of extremes of sea conditions that can, if applied without correction factors, lead to the underestimation of flood risk and under-design of coastal structures. This paper describes the application of a robust multivariate statistical model to analyse extreme offshore waves, wind and sea levels around the coast of England. The approach described here is risk based in that it seeks to define extremes of response variables directly, rather than the joint extremes of sea conditions. The output of the statistical model comprises a Monte Carlo simulation of extreme events. These distributions of extreme events have been transformed from offshore to nearshore using a statistical emulator of a wave transformation model. The resulting nearshore extreme sea condition distributions have the potential to be applied for a range of purposes. The application is demonstrated using two structures located on the south coast of England

Caste development and reproduction: a genome-wide analysis of hallmarks of insect eusociality

The honey bee queen and worker castes are a model system for developmental plasticity. We used established expressed sequence tag information for a Gene Ontology based annotation of genes that are differentially expressed during caste development. Metabolic regulation emerged as a major theme, with a caste-specific difference in the expression of oxidoreductases vs. hydrolases. Motif searches in upstream regions revealed group-specific motifs, providing an entry point to cis-regulatory network studies on caste genes. For genes putatively involved in reproduction, meiosis-associated factors came out as highly conserved, whereas some determinants of embryonic axes either do not have clear orthologs (bag of marbles, gurken, torso), or appear to be lacking (trunk) in the bee genome. Our results are the outcome of a first genome-based initiative to provide an annotated framework for trends in gene regulation during female caste differentiation (representing developmental plasticity) and reproduction

Growth analysis in the potato crop under different irrigation levels

Conduziu-se um experimento na Fazenda São Manoel, localizada em São Manuel, SP, pertencente à Faculdade de Ciências Agronômicas da Universidade Estadual Paulista, com o objetivo de avaliar os efeitos de diferentes lâminas de irrigação no crescimento da cultura da batata (Solanum tuberosum ssp. tuberosum), cultivar Aracy. O ensaio foi instalado em um Latossolo Vermelho-Escuro, textura arenosa, sob uma cobertura de plástico. O delineamento experimental utilizado foi o de blocos ao acaso, com cinco tratamentos, cinco coletas de plantas para fins de análise de crescimento, e quatro repetições. Os tratamentos consistiam em irrigar a batata quando a tensão da água no solo atingia 15, 35, 55, 75 e 1.500 kPa. O aumento nas lâminas de irrigação induz incremento no índice de área foliar, na duração da área foliar, na taxa de crescimento relativo e na taxa assimilatória líquida. _________________________________________________________________________________________ ABSTRACT: An experiment was carried out at Fazenda São Manoel, pertaining to the Faculdade de Ciências Agronômicas of the Universidade Estadual Paulista, São Manuel, SP, Brazil, to evaluate irrigation levels in the potato (Solanum tuberosum ssp. tuberosum) growth, cv. Aracy. This work was installed in a sandy Dark-Red Latosol, under a plastic cover. The experimental design was an entirely randomized block composed by irrigation in the potato plots when the soil water potential has reached 15, 35, 55, 75 and 1,500 kPa, and five plant sampling time with four replicates. It was found that higher irrigation levels led to increase of the leaf area index, leaf area duration, relative growth rate and net assimilation rate

International Influences and Drag: Just a Case of Tucking or Binding?

Recently there has been an  internationalisation in the training of UK drag performers. Whilst papers exist focused on drag kings and queens related to their community, few explore how kings/queens train – and fewer still explore international aspects. There are formal courses for drag, but historically this training was informal, present within specific performance communities built around LGBTQ cultures. Tracing dominant figures in such training – the drag mother/father – in order to historicise and contextualise the current explosion in drag performance,the paper argues that the potential globalisation of drag is largely down to the diversification of sources of knowledge available via the internet. Traditionally, performers trained with an established practitioner, where regional variances of drag were passed on. However, current new performers often learn ‘tricks of the trade’ through internet videos posted by people on other continents. In these videos, practitioners pass on their knowledge from the perspective of their locality, as if universal. New kings/queens are not passive in this training and locally infuse their acts, yet historical and local erasures persist. The paper argues that to engage with drag as performance one must be aware of locality and the deep connects drag has with its communities

Overview of Land Use Transport Models

The previous chapters in this Handbook have shown that spatial development, or land use, determines the need for spatial interaction, or transport, but that transport, by the accessibility it provides, also determines spatial development. However, it is difficult to empirically isolate impacts of land use on transport and vice versa because of the multitude of concurrent changes of other factors. This poses a problem if the likely impacts of integrated land-use and transport policies to reduce the demand for travel are to be predicted. There are principally three methods to predict those impacts. The first is to ask people how they would change their location and mobility behaviour if certain factors, such as land use regulations or transport costs, would change ('stated preference'). The second consists of drawing conclusions from observed decision behaviour of people under different conditions on how they would be likely to behave if these factors would change ('revealed preference'). The third method is to simulate human decision behaviour in mathematical models. All three methods have their advantages and disadvantages. Surveys can reveal also subjective factors of location and mobility decisions, however, their respondents can only make conjec-tures about how they would behave in still unknown situations, and the validity of such con