16,131 research outputs found

    Visuospatial tasks suppress craving for cigarettes.

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    The Elaborated Intrusion (EI) theory of desire posits that visual imagery plays a key role in craving. We report a series of experiments testing this hypothesis in a drug addiction context. Experiment 1 showed that a mental visual imagery task with neutral content reduced cigarette craving in abstaining smokers, but that an equivalent auditory task did not. The effect of visual imagery was replicated in Experiment 2, which also showed comparable effects of non-imagery visual working memory interference. Experiment 3 showed that the benefit of visual over auditory interference was not dependent upon imagery being used to induce craving. Experiment 4 compared a visuomotor task, making shapes from modeling clay, with a verbal task (counting back from 100), and again showed a benefit of the visual over the non-visual task. We conclude that visual imagery supports craving for cigarettes. Competing imagery or visual working memory tasks may help tackle craving in smokers trying to quit

    Is a Simple Collisionless Relic Dark Matter Particle Ruled Out?

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    The central densities of dark matter (DM) halos are much lower than predicted in cold DM models of structure formation. Confirmation that they have cores with a finite central density would allow us to rule out many popular types of collisionless particle as candidates for DM. Any model that leads to cusped halos (such as cold DM) is already facing serious difficulties on small scales and hot DM models have been excluded. Here I show that fermionic warm DM is inconsistent with the wide range of phase space densities in the DM halos of well-observed nearby galaxies.Comment: 6 pages, 1 figure, LaTeX uses emulateapj.sty, revised version to appear in ApJ Letters. Argument clarified and strengthened in response to criticism, conclusions little change

    Electron Transfer in Donor-Acceptor Systems: Many-Particle Effects and Influence of Electronic Correlations

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    We investigate electron transfer processes in donor-acceptor systems with a coupling of the electronic degrees of freedom to a common bosonic bath. The model allows to study many-particle effects and the influence of the local Coulomb interaction U between electrons on donor and acceptor sites. Using the non-perturbative numerical renormalization group approach we find distinct differences between the electron transfer characteristics in the single- and two-particle subspaces. We calculate the critical electron-boson coupling alpha_c as a function of UU and show results for density-density correlation functions in the whole parameter space. The possibility of many-particle (bipolaronic) and Coulomb-assisted transfer is discussed.Comment: 4 pages, 4 figure

    Eigenvalue Separation in Some Random Matrix Models

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    The eigenvalue density for members of the Gaussian orthogonal and unitary ensembles follows the Wigner semi-circle law. If the Gaussian entries are all shifted by a constant amount c/Sqrt(2N), where N is the size of the matrix, in the large N limit a single eigenvalue will separate from the support of the Wigner semi-circle provided c > 1. In this study, using an asymptotic analysis of the secular equation for the eigenvalue condition, we compare this effect to analogous effects occurring in general variance Wishart matrices and matrices from the shifted mean chiral ensemble. We undertake an analogous comparative study of eigenvalue separation properties when the size of the matrices are fixed and c goes to infinity, and higher rank analogues of this setting. This is done using exact expressions for eigenvalue probability densities in terms of generalized hypergeometric functions, and using the interpretation of the latter as a Green function in the Dyson Brownian motion model. For the shifted mean Gaussian unitary ensemble and its analogues an alternative approach is to use exact expressions for the correlation functions in terms of classical orthogonal polynomials and associated multiple generalizations. By using these exact expressions to compute and plot the eigenvalue density, illustrations of the various eigenvalue separation effects are obtained.Comment: 25 pages, 9 figures include

    ‘Everything causes cancer’: how Australians respond to the message that alcohol causes cancer

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    Over 5000 Australians are diagnosed with alcohol-related cancers annually, with growing evidence that low-levels of chronic alcohol consumption significantly increases cancer risk. Public knowledge of the link between alcohol and cancer is limited and, therefore, alcohol consumers may be inadvertently putting themselves at increased risk of developing cancer. Informing the community of alcohol-related cancer risk is important to reduce the burden of disease, however, the message that alcohol causes cancer may challenge current understanding of the risks and benefits associated with alcohol consumption. We examine how Australian adults who self-identify as light-to-moderate alcohol consumers, respond to the message that alcohol causes cancer. Seven focus groups with males and females aged between 18 and 65 years of age were audio–visually recorded, with transcripts thematically analysed within a social constructionist epistemology informed by critical realism. Cancer was represented as an inevitable part of life and something over which participants had no control: consequently, altering alcohol consumption to reduce cancer risk was not justifiable. Participants worked to present themselves as ‘normal’ consumers of alcohol by recounting personal experiences and depicting an obligation to uphold societal expectations to consume alcohol. Through the construction of cancer as an inescapable disease, and their own alcohol consumption as unproblematic and socially sanctioned, participants were able to resist the message that alcohol causes cancer, and any implied need to alter personal alcohol consumption to reduce the risk of cancer.Natalie May, Jaklin Eliott and Shona Crab

    The open cluster NGC 6520 and the nearby dark molecular cloud Barnard 86

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    Wide field BVI photometry and 12^{12}CO(1→\to0) observations are presen ted in the region of the open cluster NGC 6520 and the dark molecular cloud Barnard~86. From the analysis of the optical data we find that the cluster is rather compact, with a radius of 1.0±\pm0.5 arcmin, smaller than previous estimates. The cluster age is 150±\pm50 Myr and the reddening EB−V_{B-V}=0.42±\pm0.10. The distance from the Sun is estimated to be 1900±\pm100 pc, and it is larger than previous estimates. We finally derive basic properties of the dark nebula Barnard 86 on the assumption that it lies at the same distance of the cluster.Comment: 21 pages, 8 eps figures (a few degraded in resolution), accepted for publication in the Astronomical Journa

    Secondary literacy across the curriculum: Challenges and possibilities

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    This paper discusses the challenges and possibilities attendant upon successfully implementing literacy across the curriculum initiatives – or ‘school language policies’ as they have come to be known - particularly at the secondary or high school level. It provides a theoretical background to these issues, exploring previous academic discussions of school language policies, and highlights key areas of concern as well as opportunity with respect to school implementation of such policies. As such, it provides a necessary conceptual background to the subsequent papers in this special issue, which focus upon the Secondary Schools’ Literacy Initiative (SSLI) – a New Zealand funded programme that aims to establish cross-curricular language and literacy policies in secondary schools

    Utilizing remote sensing of Thematic Mapper data to improve our understanding of estuarine processes and their influence on the productivity of estuarine-dependent fisheries

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    LANDSAT thematic mapper (TM) data are being used to refine and validate a stochastic spatial computer model to be applied to coastal resource management problems in Louisiana. Two major aspects of the research are: (1) the measurement of area of land (or emergent vegetation) and water and the length of the interface between land and water in TM imagery of selected coastal wetlands (sample marshes); and (2) the comparison of spatial patterns of land and water in the sample marshes of the imagery to that in marshes simulated by a computer model. In addition to activities in these two areas, the potential use of a published autocorrelation statistic is analyzed
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