2,452 research outputs found

    Evidence for Kosterlitz-Thouless type orientational ordering of CF3_3Br monolayers physisorbed on graphite

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    Monolayers of the halomethane CF3_3Br adsorbed on graphite have been investigated by x-ray diffraction. The layers crystallize in a commensurate triangular lattice. On cooling they approach a three-sublattice antiferroelectric pattern of the in-plane components of the dipole moments. The ordering is not consistent with a conventional phase transition, but points to Kosterlitz-Thouless behavior. It is argued that the transition is described by a 6-state clock model on a triangular lattice with antiferromagnetic nearest neighbor interactions which is studied with Monte-Carlo simulations. A finite-size scaling analysis shows that the ordering transition is indeed in the KT universality class.Comment: 4 pages, 5 figure

    Critical behavior of the frustrated antiferromagnetic six-state clock model on a triangular lattice

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    We study the anti-ferromagnetic six-state clock model with nearest neighbor interactions on a triangular lattice with extensive Monte-Carlo simulations. We find clear indications of two phase transitions at two different temperatures: Below TIT_I a chirality order sets in and by a thorough finite size scaling analysis of the specific heat and the chirality correlation length we show that this transition is in the Ising universality class (with a non-vanishing chirality order parameter below TIT_I). At TKT(<TI)T_{KT}(<T_I) the spin-spin correlation length as well as the spin susceptibility diverges according to a Kosterlitz-Thouless (KT) form and spin correlations decay algebraically below TKTT_{KT}. We compare our results to recent x-ray diffraction experiments on the orientational ordering of CF3_3Br monolayers physisorbed on graphite. We argue that the six-state clock model describes the universal feature of the phase transition in the experimental system and that the orientational ordering belongs to the KT universality class.Comment: 8 pages, 9 figure

    Toward a Social Practice Theory of Relational Competing

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    This paper brings together the competitive dynamics and strategy-aspractice literatures to investigate relational competition. Drawing on a global ethnography of the reinsurance market, we develop the concept of micro-competitions, which are the focus of competitors’ everyday competitive practices. We find variation in relational or rivalrous competition by individual competitors across the phases of a micro-competition, between competitors within a micro-competition, and across multiple micro-competitions. These variations arise from the interplay between the unfolding competitive arena and the implementation of each firm’s strategic portfolio. We develop a conceptual framework that makes four contributions to: relational competition; reconceptualizing action and response; elaborating on the awareness-motivation-capability framework within competitive dynamics; and the recursive dynamic by which implementing strategy inside firms shapes, and is shaped by, the competitive arena

    Influence of ultrasound-assisted par-frying on crust formation and browning during the production of French fries

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    Frying is a key processing step during the production of French fries and important for end product quality and sensory attributes. It is governed by heat and mass transfer between the frying oil and the potato strips. Crust and color of the French fries are key quality parameters and important in consumer perception. Crust formation is a result of combined heat and mass transfer effects. Convective heat transfer from frying oil to potato strips and heat conduction within the tissue cause water evaporation. Mass transfer occurs in the form of water vapor release to the frying oil and oil absorption in the outer layers of the potato strips. Browning of French fries is related to Maillard reactions between reducing sugars and amino acids. High contents of reducing sugars are often related to an undesired dark color and bitter taste of French fries. High-intensity ultrasound transmitted to liquid media causes cavitation and microstreaming, which can influence boundary layers and cell structures and result in improved heat and mass transfer. The influence of an ultrasound treatment of potato strips during the par-frying step was investigated in order to determine the effect on the resulting changes in product quality. Improved heat transfer at the product surface due to micro-streaming in the oil and a facilitated release of vapor from the product surface was observed. A faster crust formation was found at the initial phase of frying but the crust was found to become softer at longer sonication times due to persistent mechanical ultrasound effects. French fries from ultrasound assisted par-frying had a lighter color after finish-frying in comparison to the conventionally par-fried samples due to an improved release of reducing sugars from the tissue. Ultrasound-assisted par-frying showed to be effective in modifying heat and mass transfer with an impact on crust formation and browning of French fries. Further work is required regarding the optimization of parameters and sonication times

    Corporal diagnostic work and diagnostic spaces: Clinicians' use of space and bodies during diagnosis

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    © 2015 The Authors. Sociology of Health & Illness © 2015 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.An emerging body of literature in sociology has demonstrated that diagnosis is a useful focal point for understanding the social dimensions of health and illness. This article contributes to this work by drawing attention to the relationship between diagnostic spaces and the way in which clinicians use their own bodies during the diagnostic process. As a case study, we draw upon fieldwork conducted with a multidisciplinary clinical team providing deep brain stimulation (DBS) to treat children with a movement disorder called dystonia. Interviews were conducted with team members and diagnostic examinations were observed. We illustrate that clinicians use communicative body work and verbal communication to transform a material terrain into diagnostic space, and we illustrate how this diagnostic space configures forms of embodied 'sensing-and-acting' within. We argue that a 'diagnosis' can be conceptualised as emerging from an interaction in which space, the clinician-body, and the patient-body (or body-part) mutually configure one another. By conceptualising diagnosis in this way, this article draws attention to the corporal bases of diagnostic power and counters Cartesian-like accounts of clinical work in which the patient-body is objectified by a disembodied medical discourse.The Wellcome Trust (Wellcome Trust Biomedical Strategic Award 086034

    The politics of valuation and payment for regenerative medicine products in the UK

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    The field of regenerative medicine (RM) faces many challenges, including funding. Framing the analysis in terms of institutional politics, valuation studies and ‘technologies of knowledge’, the paper highlights growing debates about payment for RM in the UK, setting this alongside escalating policy debates about ‘value’. We draw on interviews and publicly available material to identify the interacting and conflicting positions of institutional stakeholders. It is concluded that while there is some common ground between institutional stakeholders such as industry and health system gatekeepers, there is significant conflict about reward systems, technology assessment methodologies and payment scenarios; a range of mostly conditional payment schemes and non-mainstream routes are being experimented with. We argue that current developments highlight a fundamental conflict between a concern for the societal value of medical technologies in a resource-limited system and a concern for engineering new reward and payment models to accommodate RM innovations

    Aging and scaling laws in ÎČ\beta-hydroquinone-clathrate

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    The dielectric permittivity of the orientational glass methanol(x=0.73)-ÎČ\beta-hydroquinone-clathrate has been studied as function of temperature and waiting time using different temperature-time-protocols. We study aging, rejuvenation and memory effects in the glassy phase and discuss similarities and differences to aging in spin-glasses. We argue that the diluted methanol-clathrate, although conceptually close to its magnetic pendants, takes an intermediate character between a true spin-glass and a pure random field system

    Scraping the Social? Issues in live social research

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    What makes scraping methodologically interesting for social and cultural research? This paper seeks to contribute to debates about digital social research by exploring how a ‘medium-specific’ technique for online data capture may be rendered analytically productive for social research. As a device that is currently being imported into social research, scraping has the capacity to re-structure social research, and this in at least two ways. Firstly, as a technique that is not native to social research, scraping risks to introduce ‘alien’ methodological assumptions into social research (such as an pre-occupation with freshness). Secondly, to scrape is to risk importing into our inquiry categories that are prevalent in the social practices enabled by the media: scraping makes available already formatted data for social research. Scraped data, and online social data more generally, tend to come with ‘external’ analytics already built-in. This circumstance is often approached as a ‘problem’ with online data capture, but we propose it may be turned into virtue, insofar as data formats that have currency in the areas under scrutiny may serve as a source of social data themselves. Scraping, we propose, makes it possible to render traffic between the object and process of social research analytically productive. It enables a form of ‘real-time’ social research, in which the formats and life cycles of online data may lend structure to the analytic objects and findings of social research. By way of a conclusion, we demonstrate this point in an exercise of online issue profiling, and more particularly, by relying on Twitter to profile the issue of ‘austerity’. Here we distinguish between two forms of real-time research, those dedicated to monitoring live content (which terms are current?) and those concerned with analysing the liveliness of issues (which topics are happening?)
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