2,558 research outputs found

    Probing the Higgs mechanism via γγW+W\gamma\gamma\to W^+W^-

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    We investigate the sensitivity of the reaction γγW+W\gamma\gamma\to W^+W^- to the Higgs sector based on the complete one-loop corrections in the minimal Standard Model and the gauged non-linear σ\sigma-model. While this sensitivity is very strong for the suppressed cross-section of equally polarized photons and longitudinal W bosons, it is only marginal for the dominant mode of transverse polarizations. The corrections within the σ\sigma-model turn out to be UV-finite in accordance with the absence of \log\MH terms in the Standard Model with a heavy Higgs boson.Comment: 12 pages uuencoded postscrip

    Associations between inattention and impulsivity ADHD symptoms and disordered eating risk in a community sample of young adults

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    BACKGROUND: Symptoms of attention deficit hyperactivity disorder (ADHD) and trait impulsivity have been associated with disordered eating but are seldom assessed in community studies, or longitudinally and little is known about the mediating mechanisms. METHODS: We tested associations between ADHD symptoms and disordered eating cross-sectionally and between trait impulsivity and disordered eating longitudinally. We utilised data from a normative cohort of young adults (642 participants: 65% female, M(age) = 23 years). Participants were classified as high risk or low risk for disordered eating using the SCOFF instrument. In the first two steps of both cross-sectional and longitudinal hierarchical logistic regression models, demographics and covariates were entered. For the cross-sectional regression, Adult ADHD self-report scale (ASRS) scores, separated into inattentive and hyperactive/impulsive symptoms, were entered in the third step. In a separate longitudinal model, Barratt impulsivity scale subscales (attentional, motor and non-planning impulsivity) were entered in the third step. Depression, as assessed by the moods and feelings questionnaire (MFQ), was examined as a mediator. RESULTS: Cross-sectionally, sex, MFQ score and inattentive symptoms predicted disordered eating risk (model R(2) = 20%). Longitudinally, sex, MFQ score and attentional impulsivity predicted disordered eating risk (model R(2) = 16%). The relationship between inattentive symptoms and the disordered eating risk was partially mediated by MFQ score, whereas the relationship between attentional impulsivity and the disordered eating risk was fully mediated by MFQ scores. CONCLUSIONS: These data highlight (1) a specific role for inattentive symptoms of ADHD and (2) the importance of both depression and impulsivity in predicting eating disorder risk

    Glassy transition in a disordered model for the RNA secondary structure

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    We numerically study a disordered model for the RNA secondary structure and we find that it undergoes a phase transition, with a breaking of the replica symmetry in the low temperature region (like in spin glasses). Our results are based on the exact evaluation of the partition function.Comment: 4 pages, 3 figure

    Statistical mechanics of RNA folding: a lattice approach

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    We propose a lattice model for RNA based on a self-interacting two-tolerant trail. Self-avoidance and elements of tertiary structure are taken into account. We investigate a simple version of the model in which the native state of RNA consists of just one hairpin. Using exact arguments and Monte Carlo simulations we determine the phase diagram for this case. We show that the denaturation transition is first order and can either occur directly or through an intermediate molten phase.Comment: 8 pages, 9 figure

    Expansion of the MANAGE Database with Forest and Drainage Studies

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    The “Measured Annual Nutrient loads from AGricultural Environments” (MANAGE) database was published in 2006 to expand an early 1980s compilation of nutrient export (load) data from cultivated and pasture/range land at the field or farm scale. Then in 2008, MANAGE was updated with 15 additional studies, and nitrogen (N) and phosphorus (P) concentrations in runoff were added. Since then, MANAGE has undergone significant expansion adding N and P water quality along with relevant management and site characteristic data from: (1) 30 runoff studies from forested land uses, (2) 91 drainage water quality studies from drained land, and (3) 12 additional runoff studies from cultivated and pasture/range land uses. In this expansion, an application timing category was added to the existing fertilizer data categories (rate, placement, formulation) to facilitate analysis of 4R Nutrient Stewardship, which emphasizes right fertilizer source, rate, time, and place. In addition, crop yield and N and P uptake data were added, although this information was only available for 21 and 7% of studies, respectively. Inclusion of these additional data from cultivated, pasture/range, and forest land uses as well as artificially drained agricultural land should facilitate expanded spatial analyses and improved understanding of regional differences, management practice effectiveness, and impacts of land use conversions and management techniques

    Zero Temperature Properties of RNA Secondary Structures

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    We analyze different microscopic RNA models at zero temperature. We discuss both the most simple model, that suffers a large degeneracy of the ground state, and models in which the degeneracy has been remove, in a more or less severe manner. We calculate low-energy density of states using a coupling perturbing method, where the ground state of a modified Hamiltonian, that repels the original ground state, is determined. We evaluate scaling exponents starting from measurements of overlaps and energy differences. In the case of models without accidental degeneracy of the ground state we are able to clearly establish the existence of a glassy phase with θ1/3\theta \simeq 1/3.Comment: 20 pages including 9 eps figure

    A deuterium nuclear magnetic resonance study of chain disorder in lamellar potassium palmitate: The effect of long and short chain guests

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    The deuterium magnetic resonance spectra of lamellar phases of host perdeuterated potassium palmitate mixed with varying amounts of guest protiated potassium octanoate and behenate and 86.3 mol% D2O are reported. At higher temperatures, the short chain guests give rise to more fluidity and the long chain guests give rise to less fluidity towards the end of the host chain. At low temperatures there are changes in the interaction between the polar head group and the water which depend on sample composition. The transition from the lamellar phase to the low temperature gel phase is investigated and in some cases the gel phase is found to be a complicated many-phase region, at least for the water. The spectral results are presented in detail but compact and empirical methods of analysis are also investigated

    A deuterium nuclear magnetic resonance study of chain disorder in lamellar potassium palmitate: The effect of long and short chain guests

    Get PDF
    The deuterium magnetic resonance spectra of lamellar phases of host perdeuterated potassium palmitate mixed with varying amounts of guest protiated potassium octanoate and behenate and 86.3 mol% D2O are reported. At higher temperatures, the short chain guests give rise to more fluidity and the long chain guests give rise to less fluidity towards the end of the host chain. At low temperatures there are changes in the interaction between the polar head group and the water which depend on sample composition. The transition from the lamellar phase to the low temperature gel phase is investigated and in some cases the gel phase is found to be a complicated many-phase region, at least for the water. The spectral results are presented in detail but compact and empirical methods of analysis are also investigated
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