2,878 research outputs found

    The Alcohol Health Alliance: the emergence of an advocacy coalition to stimulate policy change

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    This paper provides an account of the emergence and early development of the Alcohol Health Alliance (AHA), a coalition of organizations including medical bodies, charities and alcohol health campaigners. Launched in 2007, the AHA aimed to re-frame awareness of alcohol consumption and related harms, to gain greater policy saliency for health compared to criminal justice priorities, and to shift policy towards adopting a population approach as compared to a targeted approach to intervention. The strategies used by the AHA to mobilize support and re-frame understanding of the alcohol problem, were successful in the short term. The alliance benefited from their links with established powerful institutions that helped them secure a strong presence within the policy arena and in the media, not least by forging relationships with political allies. However, in the longer term, it may be difficult to maintain a position of strength and to combat pre-existing entrenched relationships that favour competing alternative perceptions of the alcohol problem and the appropriate policy response

    Magnetic aspects of QCD at finite density and temperature

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    Some magnetic aspects of QCD are discussed at finite density and temperature. Possibility of spontaneous magnetization is studied within Landau Fermi-liquid theory, and the important roles of the screening effects for gluon propagation are elucidated. Static screening for the longitudinal gluons improves the infrared singularities, while the transverse gluons receive only dynamic screening. The latter property gives rise to a novel non-Fermi-liquid behaviour for the magnetic susceptibility. Appearance of a density-wave state is also discussed in relation to chiral transition, where pseudoscalar condensate as well as scalar one takes a spatially non-uniform form in a chirally invariant way. Accordingly magnetization of quark matter oscillates like spin density wave. A hadron-quark continuity is suggested in this aspect, remembering pion condensation in hadronic phase.Comment: 6 pages, 8 figures, Proc. of INPN2010 to appear in J. Phy

    Anisotropic dynamics of a vicinal surface under the meandering step instability

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    We investigate the nonlinear evolution of the Bales-Zangwill instability, responsible for the meandering of atomic steps on a growing vicinal surface. We develop an asymptotic method to derive, in the continuous limit, an evolution equation for the two-dimensional step flow. The dynamics of the crystal surface is greatly influenced by the anisotropy inherent to its geometry, and is characterized by the coarsening of undulations along the step direction and by the elastic relaxation in the mean slope direction. We demonstrate, using similarity arguments, that the coalescence of meanders and the step flow follow simple scaling laws, and deduce the exponents of the characteristic length scales and height amplitude. The relevance of these results to experiments is discussed.Comment: 10 pages, 7 figures; submitted to Phys. Rev.

    Identifying promising approaches and initiatives to reducing alcohol related harm

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    This study aimed to identify promising approaches that could be included in multi-component programmes (MCPs) to reduce alcohol related harm at local level in the UK. MCPs involve the identification of alcohol related problems at the local level and implementation of a programme of co-ordinated projects to tackle a problem. They are based on an integrative design where singular interventions run in combination with each other and/or are sequenced together over time; the identification, coordination and mobilisation of local agencies, stakeholders and community are key elements (Thom and Bayley, 2007). This study was underpinned by the recognition that the voices of practitioners are often marginalised in the debates about ‘what works’ and it set out to include their views. So whilst acknowledging the importance of the international research literature, care was taken not to privilege it over other ‘softer’ sources e.g. knowledge and experience of practitioners

    Non-collinear coupling between magnetic adatoms in carbon nanotubes

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    The long range character of the exchange coupling between localized magnetic moments indirectly mediated by the conduction electrons of metallic hosts often plays a significant role in determining the magnetic order of low-dimensional structures. In addition to this indirect coupling, here we show that the direct exchange interaction that arises when the moments are not too far apart may induce a non-collinear magnetic order that cannot be characterized by a Heisenberg-like interaction between the magnetic moments. We argue that this effect can be manipulated to control the magnetization alignment of magnetic dimers adsorbed to the walls of carbon nanotubes.Comment: 13 pages, 5 figures, submitted to PR

    Magnetic and electric properties of double-perovskites and estimation of their Curie temperatures by ab initio calculations

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    First principles electronic structure calculations have been carried out on ordered double perovskites Sr_2B'B"O_6 (for B' = Cr or Fe and B" 4d and 5d transition metal elements) with increasing number of valence electrons at the B-sites, and on Ba_2MnReO_6 as well as Ba_2FeMoO_6. The Curie temperatures are estimated ab initio from the electronic structures obtained with the local spin-density functional approximation, full-potential generalized gradient approximation and/or the LDA+U method (U - Hubbard parameter). Frozen spin-spirals are used to model the excited states needed to evaluate the spherical approximation for the Curie temperatures. In cases, where the induced moments on the oxygen was found to be large, the determination of the Curie temperature is improved by additional exchange functions between the oxygen atoms and between oxygen and B' and B" atoms. A pronounced systematics can be found among the experimental and/or calculated Curie temperatures and the total valence electrons of the transition metal elements.Comment: 8 pages, 11 figures. Submitted to the Physical Review

    Eulerian spectral closures for isotropic turbulence using a time-ordered fluctuation-dissipation relation

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    Procedures for time-ordering the covariance function, as given in a previous paper (K. Kiyani and W.D. McComb Phys. Rev. E 70, 066303 (2004)), are extended and used to show that the response function associated at second order with the Kraichnan-Wyld perturbation series can be determined by a local (in wavenumber) energy balance. These time-ordering procedures also allow the two-time formulation to be reduced to time-independent form by means of exponential approximations and it is verified that the response equation does not have an infra-red divergence at infinite Reynolds number. Lastly, single-time Markovianised closure equations (stated in the previous paper above) are derived and shown to be compatible with the Kolmogorov distribution without the need to introduce an ad hoc constant.Comment: 12 page

    Broken-symmetry-adapted Green function theory of condensed matter systems:towards a vector spin-density-functional theory

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    The group theory framework developed by Fukutome for a systematic analysis of the various broken symmetry types of Hartree-Fock solutions exhibiting spin structures is here extended to the general many body context using spinor-Green function formalism for describing magnetic systems. Consequences of this theory are discussed for examining the magnetism of itinerant electrons in nanometric systems of current interest as well as bulk systems where a vector spin-density form is required, by specializing our work to spin-density-functional formalism. We also formulate the linear response theory for such a system and compare and contrast them with the recent results obtained for localized electron systems. The various phenomenological treatments of itinerant magnetic systems are here unified in this group-theoretical description.Comment: 17 page

    First-Principles Study of Electronic Structure in α\alpha-(BEDT-TTF)2_2I3_3 at Ambient Pressure and with Uniaxial Strain

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    Within the framework of the density functional theory, we calculate the electronic structure of α\alpha-(BEDT-TTF)2_2I3_3 at 8K and room temperature at ambient pressure and with uniaxial strain along the aa- and bb-axes. We confirm the existence of anisotropic Dirac cone dispersion near the chemical potential. We also extract the orthogonal tight-binding parameters to analyze physical properties. An investigation of the electronic structure near the chemical potential clarifies that effects of uniaxial strain along the a-axis is different from that along the b-axis. The carrier densities show T2T^2 dependence at low temperatures, which may explain the experimental findings not only qualitatively but also quantitatively.Comment: 10 pages, 7 figure

    Extremely Correlated Quantum Liquids

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    We formulate the theory of an extremely correlated electron liquid, generalizing the standard Fermi liquid. This quantum liquid has specific signatures in various physical properties, such as the Fermi surface volume and the narrowing of electronic bands by spin and density correlation functions. We use Schwinger's source field idea to generate equations for the Greens function for the Hubbard operators. A local (matrix) scale transformation in the time domain to a quasiparticle Greens function, is found to be optimal. This transformation allows us to generate vertex functions that are guaranteed to reduce to the bare values for high frequencies, i.e. are ``asymptotically free''. The quasiparticles are fractionally charged objects, and we find an exact Schwinger Dyson equation for their Greens function. We find a hierarchy of equations for the vertex functions, and further we obtain Ward identities so that systematic approximations are feasible. An expansion in terms of the density of holes measured from the Mott Hubbard insulating state follows from the nature of the theory. A systematic presentation of the formalism is followed by some preliminary explicit calculations.Comment: 40 pages, typos remove
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