473 research outputs found

    On two-temperature problem for harmonic crystals

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    We consider the dynamics of a harmonic crystal in dd dimensions with nn components,d,n1d,n \ge 1. The initial date is a random function with finite mean density of the energy which also satisfies a Rosenblatt- or Ibragimov-Linnik-type mixing condition. The random function converges to different space-homogeneous processes as xd±x_d\to\pm\infty, with the distributions μ±\mu_\pm. We study the distribution μt\mu_t of the solution at time tRt\in\R. The main result is the convergence of μt\mu_t to a Gaussian translation-invariant measure as tt\to\infty. The proof is based on the long time asymptotics of the Green function and on Bernstein's `room-corridor' argument. The application to the case of the Gibbs measures μ±=g±\mu_\pm=g_\pm with two different temperatures T±T_{\pm} is given. Limiting mean energy current density is (0,...,0,C(T+T))- (0,...,0,C(T_+ - T_-)) with some positive constant C>0C>0 what corresponds to Second Law

    Electroweak and finite width corrections to top quark decays into transverse and longitudinal W W -bosons

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    We calculate the electroweak and finite width corrections to the decay of an unpolarized top quark into a bottom quark and a W W -gauge boson where the helicities of the W W are specified as longitudinal, transverse-plus and transverse-minus. Together with the O(αs) O(\alpha_s) corrections these corrections may become relevant for the determination of the mass of the top quark through angular decay measurements.Comment: 4 pages, 7 postscript figures adde

    Leptonic μ \mu - and τ \tau -decays: mass effects, polarization effects and O(α) O(\alpha) radiative corrections

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    We calculate the radiative corrections to the unpolarized and the four polarized spectrum and rate functions in the leptonic decay of a polarized μ \mu into a polarized electron. The new feature of our calculation is that we keep the mass of the final state electron finite which is mandatory if one wants to investigate the threshold region of the decay. Analytical results are given for the energy spectrum and the polar angle distribution of the final state electron whose longitudinal and transverse polarization is calculated. We also provide analytical results on the integrated spectrum functions. We analyze the me0 m_e \to 0 limit of our general results and investigate the quality of the me0 m_e \to 0 approximation. In the me0 m_e \to 0 case we discuss in some detail the role of the O(α) O(\alpha) anomalous helicity flip contribution of the final electron which survives the me0 m_e \to 0 limit. The results presented in this 0203048 also apply to the leptonic decays of polarized τ \tau -leptons for which we provide numerical results.Comment: 39 pages, 11 postscript figures added. Updated version. Four references added. A few text improvements. Final version to appear in Phys.Rev.

    Political branding: sense of identity or identity crisis? An investigation of the transfer potential of the brand identity prism to the UK Conservative Party

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    Brands are strategic assets and key to achieving a competitive advantage. Brands can be seen as a heuristic device, encapsulating a series of values that enable the consumer to make quick and efficient choices. More recently, the notion of a political brand and the rhetoric of branding have been widely adopted by many political parties as they seek to differentiate themselves, and this has led to an emerging interest in the idea of the political brand. Therefore, this paper examines the UK Conservative Party brand under David Cameron’s leadership and examines the applicability of Kapferer’s brand identity prism to political branding. This paper extends and operationalises the brand identity prism into a ‘political brand identity network’ which identifies the inter-relatedness of the components of the corporate political brand and the candidate political brand. Crucial for practitioners, this model can demonstrate how the brand is presented and communicated to the electorate and serves as a useful mechanism to identify consistency within the corporate and candidate political brands

    Requirements for Power Hardware-in-the-Loop Emulation of Distribution Grid Challenges

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    The ongoing transition of low voltage (LV) power grids towards active systems requires novel evaluation and testing concepts, in particular for realistic testing of devices. Power Hardware-in-the-Loop (PHIL) evaluations are a promising approach for this purpose. This paper presents preliminary investigations addressing the systematic design of PHIL applications and their applicable stability mechanisms and gives a detailed review of the related work. A requirement analysis for emulation of grid situations demanding system services is given and the realization of a PHIL setup is demonstrated in a residential scenario, comprising a hybrid electrical energy storage system (HESS)

    Resonant Thermoelectric Nanophotonics

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    Photodetectors are typically based either on photocurrent generation from electron–hole pairs in semiconductor structures or on bolometry for wavelengths that are below bandgap absorption. In both cases, resonant plasmonic and nanophotonic structures have been successfully used to enhance performance. Here, we show subwavelength thermoelectric nanostructures designed for resonant spectrally selective absorption, which creates large localized temperature gradients even with unfocused, spatially uniform illumination to generate a thermoelectric voltage. We show that such structures are tunable and are capable of wavelength-specific detection, with an input power responsivity of up to 38 V W^(–1), referenced to incident illumination, and bandwidth of nearly 3 kHz. This is obtained by combining resonant absorption and thermoelectric junctions within a single suspended membrane nanostructure, yielding a bandgap-independent photodetection mechanism. We report results for both bismuth telluride/antimony telluride and chromel/alumel structures as examples of a potentially broader class of resonant nanophotonic thermoelectric materials for optoelectronic applications such as non-bandgap-limited hyperspectral and broadband photodetectors

    Coupling changes in cell shape to chromosome segregation

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    Animal cells undergo dramatic changes in shape, mechanics and polarity as they progress through the different stages of cell division. These changes begin at mitotic entry, with cell–substrate adhesion remodelling, assembly of a cortical actomyosin network and osmotic swelling, which together enable cells to adopt a near spherical form even when growing in a crowded tissue environment. These shape changes, which probably aid spindle assembly and positioning, are then reversed at mitotic exit to restore the interphase cell morphology. Here, we discuss the dynamics, regulation and function of these processes, and how cell shape changes and sister chromatid segregation are coupled to ensure that the daughter cells generated through division receive their fair inheritance

    The cost of severe haemophilia in Europe: the CHESS study

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    Background Severe haemophilia is associated with major psychological and economic burden for patients, caregivers, and the wider health care system. This burden has been quantified and documented for a number of European countries in recent years. However, few studies have taken a standardised methodology across multiple countries simultaneously, and sought to amalgamate all three levels of burden for severe disease. The overall aim of the ‘Cost of Haemophilia in Europe: a Socioeconomic Survey’ (CHESS) study was to capture the annualised economic and psychosocial burden of severe haemophilia in five European countries. A cross-section of haemophilia specialists (surveyed between January and April 2015) provided demographic and clinical information and 12-month ambulatory and secondary care activity for patients via an online survey. In turn, patients provided corresponding direct and indirect non-medical cost information, including work loss and out-of-pocket expenses, as well as information on quality of life and adherence. The direct and indirect costs for the patient sample were calculated and extrapolated to population level. Results Clinical reports for a total of 1,285 patients were received. Five hundred and fifty-two patients (43% of the sample) provided information on indirect costs and health-related quality of life via the PSC. The total annual cost of severe haemophilia across the five countries for 2014 was estimated at EUR 1.4 billion, or just under EUR 200,000 per patient. The highest per-patient costs were in Germany (mean EUR 319,024) and the lowest were in the United Kingdom (mean EUR 129,365), with a study average of EUR 199,541. As expected, consumption of clotting factor replacement therapy represented the vast majority of costs (up to 99%). Indirect costs are driven by patient and caregiver work loss. Conclusions The results of the CHESS study reflect previous research findings suggesting that costs of factor replacement therapy account for the vast majority of the cost burden in severe haemophilia. However, the importance of the indirect impact of haemophilia on the patient and family should not be overlooked. The CHESS study highlights the benefits of observational study methodologies in capturing a ‘snapshot’ of information for patients with rare diseases

    Sustainable Urban Systems: Co-design and Framing for Transformation

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    Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social–ecological–technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at multiple scales. Such holistic urban approaches are rare in practice. A co-design process involving researchers, practitioners and other stakeholders, has progressed such an approach in the Australian context, aiming to also contribute to international knowledge development and sharing. This process has generated three outputs: (1) a shared framework to support more systematic knowledge development and use, (2) identification of barriers that create a gap between stated urban goals and actual practice, and (3) identification of strategic focal areas to address this gap. Developing integrated strategies at broader urban scales is seen as the most pressing need. The knowledge framework adopts a systems perspective that incorporates the many urban trade-offs and synergies revealed by a systems view. Broader implications are drawn for policy and decision makers, for researchers and for a shared forward agenda
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