15,280 research outputs found

    Economic performance or electoral necessity? Evaluating the system of voluntary income to political parties

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    Whilst the public funding of political parties is the norm in western democracies, its comprehensive introduction has been resisted in Britain. Political and electoral arrangements in Britain require parties to function and campaign on a regular basis, whilst their income follows cycles largely related to general elections. This article shows that the best predictor of party income is the necessity of a well-funded general election campaign rather than party performance. As a result, income can only be controlled by parties to a limited degree, which jeopardises their ability to determine their own financial position and fulfil their functions as political parties

    The application of the global isomorphism to the surface tension of the liquid-vapor interface of the Lennard-Jones fluids

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    In this communication we show that the surface tension of the real fluids of the Lennard-Jones type can be obtained from the surface tension of the lattice gas (Ising model) on the basis of the global isomorphism approach developed earlier for the bulk properties.Comment: 8 pages, 6 figure

    Phase diagrams in the lattice RPM model: from order-disorder to gas-liquid phase transition

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    The phase behavior of the lattice restricted primitive model (RPM) for ionic systems with additional short-range nearest neighbor (nn) repulsive interactions has been studied by grand canonical Monte Carlo simulations. We obtain a rich phase behavior as the nn strength is varied. In particular, the phase diagram is very similar to the continuum RPM model for high nn strength. Specifically, we have found both gas-liquid phase separation, with associated Ising critical point, and first-order liquid-solid transition. We discuss how the line of continuous order-disorder transitions present for the low nn strength changes into the continuum-space behavior as one increases the nn strength and compare our findings with recent theoretical results by Ciach and Stell [Phys. Rev. Lett. {\bf 91}, 060601 (2003)].Comment: 7 pages, 10 figure

    Genetic architecture of the white matter connectome of the human brain

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    White matter tracts form the structural basis of large-scale functional networks in the human brain. We applied brain-wide tractography to diffusion images from 30,810 adult participants (UK Biobank), and found significant heritability for 90 regional connectivity measures and 851 tract-wise connectivity measures. Multivariate genome- wide association analyses identified 355 independently associated lead SNPs across the genome, of which 77% had not been previously associated with human brain metrics. Enrichment analyses implicated neurodevelopmental processes including neurogenesis, neural differentiation, neural migration, neural projection guidance, and axon development, as well as prenatal brain expression especially in stem cells, astrocytes, microglia and neurons. We used the multivariate association profiles of lead SNPs to identify 26 genomic loci implicated in structural connectivity between core regions of the left-hemisphere language network, and also identified 6 loci associated with hemispheric left-right asymmetry of structural connectivity. Polygenic scores for schizophrenia, bipolar disorder, autism spectrum disorder, attention-deficit hyperactivity disorder, left-handedness, Alzheimer’s disease, amyotrophic lateral sclerosis, and epilepsy showed significant multivariate associations with structural connectivity, each implicating distinct sets of brain regions with trait-relevant functional profiles. This large-scale mapping study revealed common genetic contributions to the structural connectome of the human brain in the general adult population, highlighting links with polygenic disposition to brain disorders and behavioural traits

    Exact dynamical AdS black holes and wormholes with a Klein-Gordon field

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    We present several classes of exact solutions in the Einstein-Klein-Gordon system with a cosmological constant. The spacetime has spherical, plane, or hyperbolic symmetry and the higher-dimensional solutions are obtained in a closed form only in the plane symmetric case. Among them, the class-I solution represents an asymptotically locally anti-de Sitter (AdS) dynamical black hole or wormhole. In four and higher dimensions, the generalized Misner-Sharp quasi-local mass blows up at AdS infinity, inferring that the spacetime is only locally AdS. In three dimensions, the scalar field becomes trivial and the solution reduces to the BTZ black hole.Comment: 11 pages, 2 figures, 2 tables; v2, results strengthened, argument on trapping horizon corrected; v3, argument on locally AdS property added, accepted for publication in Physical Review

    Bulk Fermi surface coexistence with Dirac surface state in Bi2_2Se3_3: a comparison of photoemission and Shubnikov-de Haas measurements

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    Shubnikov de Haas (SdH) oscillations and Angle Resolved PhotoEmission Spectroscopy (ARPES) are used to probe the Fermi surface of single crystals of Bi2Se3. We find that SdH and ARPES probes quantitatively agree on measurements of the effective mass and bulk band dispersion. In high carrier density samples, the two probes also agree in the exact position of the Fermi level EF, but for lower carrier density samples discrepancies emerge in the position of EF. In particular, SdH reveals a bulk three-dimensional Fermi surface for samples with carrier densities as low as 10^17cm-3. We suggest a simple mechanism to explain these differences and discuss consequences for existing and future transport studies of topological insulators.Comment: 5 mages, 5 figure

    Existence of temperature on the nanoscale

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    We consider a regular chain of quantum particles with nearest neighbour interactions in a canonical state with temperature TT. We analyse the conditions under which the state factors into a product of canonical density matrices with respect to groups of nn particles each and under which these groups have the same temperature TT. In quantum mechanics the minimum group size nminn_{min} depends on the temperature TT, contrary to the classical case. We apply our analysis to a harmonic chain and find that nmin=const.n_{min} = const. for temperatures above the Debye temperature and nminT3n_{min} \propto T^{-3} below.Comment: Version that appeared in PR

    Non-universal size dependence of the free energy of confined systems near criticality

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    The singular part of the finite-size free energy density fsf_s of the O(n) symmetric ϕ4\phi^4 field theory in the large-n limit is calculated at finite cutoff for confined geometries of linear size L with periodic boundary conditions in 2 < d < 4 dimensions. We find that a sharp cutoff Λ\Lambda causes a non-universal leading size dependence fsΛd2L2f_s \sim \Lambda^{d-2} L^{-2} near TcT_c which dominates the universal scaling term Ld\sim L^{-d}. This implies a non-universal critical Casimir effect at TcT_c and a leading non-scaling term L2\sim L^{-2} of the finite-size specific heat above TcT_c.Comment: RevTex, 4 page

    Density-functional theory of freezing of vortex-liquid in quasi two-dimensional superconductors

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    We present a theory of vortex liquid-to-solid transition in homogeneous quasi 2D superconductors. The free energy is written as a functional l of density of zeroes of the fluctuating order parameter. The transition is weakly first-order and well below the Hc2(T) line. Transition temperature, discontinuities of the average Abrikosov ratio and of the average superfluid density, the Debay-Waller factor and the latent heat are in good agreement with Monte Carlo simulations. The density is only weakly modulated in the "vortex-solid" phase, consistent with the density-wave behavior.Comment: 12 pages and 1 figure available upon request, LaTex Version 2.09, submitted to Phys. Rev. Let
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