8,859 research outputs found

    The Ageing European Workforce

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    One may postulate that increased longevity has automatically translated into longer working lives, but that this is not necessarily the case in Europe. For example, the French have amongst the highest longevity in Europe, yet they retire much earlier than many of their fellow Europeans

    Spirits, iconoclasts and the borders of the market in urban Vietnam

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    This study takes as its object a goddess called the Lady of the Realm, whose shrine is in a rural area in the southern part of Vietnam. This goddess provides a valuable window onto changes underway in reform-era Vietnam for in recent years she has become the focus of a major pilgrimage and the controversial object of much commentary and debate

    Role of electrostatic forces in cluster formation in a dry ionomer

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    This simulation study investigates the dependence of the structure of dry Nafion®^{\tiny\textregistered}-like ionomers on the electrostatic interactions between the components of the molecules. In order to speed equilibration, a procedure was adopted which involved detaching the side chains from the backbone and cutting the backbone into segments, and then reassembling the macromolecule by means of a strong imposed attractive force between the cut ends of the backbone, and between the non-ionic ends of the side chains and the midpoints of the backbone segments. Parameters varied in this study include the dielectric constant, the free volume, side-chain length, and strength of head-group interactions. A series of coarse-grained mesoscale simulations shows the morphlogy to depend sensitively on the ratio of the strength of the dipole-dipole interactions between the side-chain acidic end groups to the strength of the other electrostatic components of the Hamiltonian. Examples of the two differing morphologies proposed by Gierke and by Gebel emerge from our simulations.Comment: 39 pages, 18 figures, accepted for publicatio

    Lightweight piston architecture

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    The invention is an improvement in a lightweight carbon-carbon composite piston, the improvement uses near-net shape knitted or warp-interlock preforms to improve the structural qualities of the piston. In its preferred embodiment, a one piece, tubular, closed-ended, knitted preform (a sock) of carbon fibers embedded within the matrix of the piston structure forms the crown, side wall, skirt and inner surface of the piston, and wrap-interlock preforms strengthen the piston crown and wrist pin bosses

    The metallicity and elemental abundance maps of kinematically atypical galaxies for constraining minor merger and accretion histories

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    © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Explaining the internal distribution and motions of stars and gas in galaxies is a key aspect in understanding their evolution. In previous work we identified five well-resolved galaxies with atypical kinematics from a cosmological simulation; two had kinematically distinct cores (KDCs), and three had counter-rotating gas and stars (CRGD). In this paper, we show that (i) the KDC galaxies have flattening of stellar [O/Fe] at large galactocentric radii due to the minor mergers that gave rise to the KDCs, and (ii) the CRGD galaxies have an abrupt transition in the gas metallicity maps, from high metallicity in the centre to very low metallicity further out. These galaxies are embedded in dark matter filaments where there is a ready supply of near-pristine gas to cause this effect. The non-linear increase in gas metallicity is also seen in the radial profiles, but when the metallicity gradients are measured, the difference is buried in the scatter of the relation. We also find that all five galaxies are fairly compact, with small effective radii given their stellar masses. This is because they have not experienced major mergers that kinematically heat the stars, and would have destroyed their unusual kinematics. In order to detect these signatures of minor mergers or accretion, the galaxy scaling relations or radial metallicity profiles are not enough, and it is necessary to obtain the two-dimensional maps with integral field spectroscopy observations.Peer reviewe

    On the [α/Fe]-[Fe/H] relations in early-type galaxies

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    This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We study how the predicted [α/Fe]-[Fe/H] relations in early-type galaxies vary as functions of their stellar masses, ages, and stellar velocity dispersions, by making use of cosmological chemodynamical simulations with feedback from active galactic nuclei. Our model includes a detailed treatment for the chemical enrichment from dying stars, core-collapse supernovae (both Type II and hypernovae) and Type Ia supernovae. At redshift z = 0, we create a catalogue of 526 galaxies, among which we determine 80 early-type galaxies. From the analysis of our simulations, we find [α/Fe]-[Fe/H] relations similar to the Galactic bulge. We also find that, in the oldest galaxies, Type Ia supernovae start to contribute at higher [Fe/H] than in the youngest ones. On the average, early-type galaxies with larger stellar masses (and, equivalently, higher stellar velocity dispersions) have higher [α/Fe] ratios, at fixed [Fe/H]. This is qualitatively consistent with the recent observations of Sybilska et al., but quantitatively there are mismatches, which might require stronger feedback, sub-classes of Type Ia Supernovae, or a variable initial mass function to address.Peer reviewedFinal Published versio

    An analysis of the key factors affecting the success of a re-launched destination marketing website in the UK

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    Business Information Systems e-Commerce/e-business Computer Appl. in Social and Behavioral Sciences Marketing Information Systems Applications (incl. Internet)This paper presents a case study of the re-launch of a DMO website in the UK. It evaluates the perceived usability of the new website and identifies the key factors affecting customers’ intention to use the new website. A large-scale online survey was developed to understand a number of issues relating to usability (e.g. aesthetics, effectiveness) and psychological and behavioural indicators (e.g. perceived trustworthiness and intent to use). Both quantitative and qualitative data was analysed to understand users’ perceptions, behaviour and attitudes towards the re-launched website. A Structural Equation Model (SEM) was developed to identify the factors affecting their intention to use the new website. The SEM model identified the impact of a variety of factors on intention to use and the descriptive analysis, using both qualitative and quantitative data, highlights further areas of research

    Predicted field-induced hexatic structure in an ionomer membrane

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    Coarse-grained molecular-dynamics simulations were used to study the morphological changes induced in a Nafion®^{\tiny \textregistered}-like ionomer by the imposition of a strong electric field. We observe the formation of novel structures aligned along the direction of the applied field. The polar head groups of the ionomer side chains aggregate into clusters, which then form rod-like formations which assemble into a hexatic array aligned with the direction of the field. Occasionally these lines of sulfonates and protons form a helical structure. Upon removal of the electric field, the hexatic array of rod-like structures persists, and has a lower calculated free energy than the original isotropic morphology.Comment: 4 pages, 7 figure
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