1,107 research outputs found

    Anatomy of three-body decay III. Energy distributions

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    We address the problem of calculating momentum distributions of particles emerging from the three-body decay of a many-body resonance. We show that these distributions are determined by the asymptotics of the coordinate-space complex-energy wave-function of the resonance. We use the hyperspherical adiabatic expansion method where all lengths are proportional to the hyperradius. The structures of the resonances are related to different decay mechanisms. For direct decay all inter-particle distances increase proportional to the hyperradius at intermediate and large distances. Sequential three-body decay proceeds via spatially confined quasi-stationary two-body configurations. Then two particles remain close while the third moves away. The wave function may contain mixtures which produce coherence effects at small distances, but the energy distributions can still be added incoherently. Two-neutron halos are discussed in details and illustrated by the 2+2^+ resonance in 6^{6}He. The dynamic evolution of the decay process is discussed.Comment: 30 pages, 8 figures, to be published in Nuclear Physics

    Combined zinc and nitrogen fertilization in different bread wheat genotypes grown under mediterranean conditions

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    The combined application of nitrogen (N) and zinc (Zn) appears to be a promising agronomic strategy for the biofortification with Zn. To evaluate such efficiency, a field experiment was conducted in south-eastern Portugal under Zn-deficient soil. Four advanced breeding lines and two commercial varieties of bread wheat (Triticum aestivum L.) were fertilized with five treatments: i) control, ii) two foliar Zn applications, iii) one foliar Zn+N application, iv) soil and two foliar Zn applications, and v) soil and one foliar Zn+N application. Grain Zn content varied greatly across treatments and INIAV-1 and the commercial varieties were the most interesting cultivars in all the treatments. Grain Zn concentrations higher than the target level of 38 mg Zn kg−1 were obtained only when two foliar Zn applications were applied, alone or in combination with soil Zn applications, and grain Zn bioavailability also was more adequate (phytate:Zn ratios similar to 15). Soil Zn application resulted in grain yield increases between 7–10%, which virtually offset the extra application cost. The combined soil and two foliar treatment could be a good option for biofortifying bread wheat under Zn-deficient soils

    Debilitating disease in a polyparasitised woylie (Bettongia penicillata): A diagnostic investigation

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    During monitoring of critically endangered woylie (Bettongia penicillata) populations within the south-west of Western Australia, an adult female woylie was euthanased after being found in extremely poor body condition with diffuse alopecia, debilitating skin lesions and severe ectoparasite infestation. Trypanosoma copemani G2 and Sarcocystis sp. were detected molecularly within tissue samples collected post-mortem. Potorostrongylus woyliei and Paraustrostrongylus sp. nematodes were present within the stomach and small intestine, respectively. Blood collected ante-mortem revealed the presence of moderate hypomagnesaemia, mild hypokalaemia, mild hyperglobulinaemia and mild hypoalbuminaemia. Diffuse megakaryocytic hypoplasia was evident within the bone marrow. We propose various hypotheses that may explain the presence of severe ectoparasite infection, skin disease and poor body condition in this woylie. Given the potential deleterious effects of parasite infection, the importance of monitoring parasites cannot be over-emphasised

    Exact 2-point function in Hermitian matrix model

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    J. Harer and D. Zagier have found a strikingly simple generating function for exact (all-genera) 1-point correlators in the Gaussian Hermitian matrix model. In this paper we generalize their result to 2-point correlators, using Toda integrability of the model. Remarkably, this exact 2-point correlation function turns out to be an elementary function - arctangent. Relation to the standard 2-point resolvents is pointed out. Some attempts of generalization to 3-point and higher functions are described.Comment: 31 pages, 1 figur

    Predictions for the 4 GeV TJNAF inclusive electron scattering experiment and for FSI effects in EMC ratios

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    We express nuclear structure functions FiAF_i^A as generalized convolutions of the structure function of a nucleon and of a nucleus, composed of point-nucleons. In computations of the latter we include Final State Interactions and results for F2AF_2^A are compared with a few directly measured data on C and Fe. The above FiAF_i^A are primarily used for predictions of the TJNAF 89-008 inclusive scattering experiment of 4 GeV electrons on various targets. Those cover a broad angular, and correspondingly wide x,Q2x,Q^2 range, where the nucleon-inelastic part dominates large sections of the covered kinematics. The same model has been applied to the study of hitherto neglected Final State Interaction effects in the nuclear component in EMC ratios in the region 0.85x0.250.85\lesssim x\lesssim 0.25.Comment: 12 page

    Cubic curves from instanton counting

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    We investigate the possibility to extract Seiberg-Witten curves from the formal series for the prepotential, which was obtained by the Nekrasov approach. A method for models whose Seiberg-Witten curves are not hyperelliptic is proposed. It is applied to the SU(N) model with one symmetric or antisymmetric representations as well as for SU(N_1)xSU(N_2) model with (N_1,N_2) or (N_1,\bar{N}_2) bifundamental matter. Solutions are compared with known results. For the gauge group product we have checked the instanton corrections which follow from our curves against direct instanton counting computations up to two instantons.Comment: 30 pages, v2. typos fixed, referenced adde

    BioJS: An open source standard for biological visualisation - its status in 2014

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    BioJS is a community-based standard and repository of functional components to represent biological information on the web. The development of BioJS has been prompted by the growing need for bioinformatics visualisation tools to be easily shared, reused and discovered. Its modular architecture makes it easy for users to find a specific functionality without needing to know how it has been built, while components can be extended or created for implementing new functionality. The BioJS community of developers currently provides a range of functionality that is open access and freely available. A registry has been set up that categorises and provides installation instructions and testing facilities at http://www.ebi.ac.uk/tools/biojs/. The source code for all components is available for ready use at https://github.com/biojs/biojs

    Charged lepton Flavor Violation in Supersymmetry with Bilinear R-Parity Violation

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    The simplest unified extension of the Minimal Supersymmetric Standard Model with bi-linear R-parity violation naturally predicts a hierarchical neutrino mass spectrum, suitable to explain atmospheric and solar neutrino fluxes. We study whether the individual violation of the lepton numbers L_{e,mu,tau} in the charged sector can lead to measurable rates for BR(mu->e gamma)and $BR(tau-> mu gamma). We find that some of the R-parity violating terms that are compatible with the observed atmospheric neutrino oscillations could lead to rates for mu->e gamma measurable in projected experiments. However, the Delta m^2_{12} obtained for those parameters is too high to be compatible with the solar neutrino data, excluding therefore the possibility of having measurable rates for mu->e gamma in the model.Comment: 29 pages, 8 figures. Constraint from solar neutrino data included, conclusions changed respect v

    Leptogenesis in Neutrino Textures with Two Zeros

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    The leptogenesis is studied in the neutrino textures with two zeros, which reduce the number of independent phases of the CP violation. The phenomenological favored neutrino textures with two zeros are decomposed into the Dirac neutrino mass matrix and the right-handed Majorana one in the see-saw mechanism. Putting the condition to suppress the μeγ\mu \to e\gamma decay enough, the texture zeros of the Dirac neutrino mass matrix are fixed in the framework of the MSSM with right-handed neutrinos. These textures have only one CP violatig phase. The magnitude of each entry of the Dirac mass matrix is determined in order to explain the baryon asymmetry of the universe by solving the Boltzman equations. The relation between the leptogenesis and the low energy CP violation is presented in these textures.Comment: Latex file with 20 pages, 6 eps figure
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