15,411 research outputs found

    Multivortex Solutions of the Weierstrass Representation

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    The connection between the complex Sine and Sinh-Gordon equations on the complex plane associated with a Weierstrass type system and the possibility of construction of several classes of multivortex solutions is discussed in detail. We perform the Painlev\'e test and analyse the possibility of deriving the B\"acklund transformation from the singularity analysis of the complex Sine-Gordon equation. We make use of the analysis using the known relations for the Painlev\'{e} equations to construct explicit formulae in terms of the Umemura polynomials which are τ\tau-functions for rational solutions of the third Painlev\'{e} equation. New classes of multivortex solutions of a Weierstrass system are obtained through the use of this proposed procedure. Some physical applications are mentioned in the area of the vortex Higgs model when the complex Sine-Gordon equation is reduced to coupled Riccati equations.Comment: 27 pages LaTeX2e, 1 encapsulated Postscript figur

    Impact of Rubin Observatory LSST Template Acquisition Strategies on Early Science from the Transients and Variable Stars Science Collaboration: Non-time-critical Science Cases

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    Vera C. Rubin Observatory Legacy Survey of Space and Time, LSST, will revolutionize modern astronomy by producing an extremely deep (coadded depth ~27 mag) depth-limited survey of the entire southern sky (LSST Science Collaboration et al. 2009). The 8.4 m large-aperture, wide-field telescope, which is based in Cerro Pachón, will image the entire Southern sky every three nights in multiple bands (SDSS-u, g, r, i, z, y) and produce a fire-hose of data, 20 Tb each night, concluding in a 60 petabyte data set as the legacy of the 10 yr survey. Extracting meaningful light curves from variable objects requires difference imaging to both identify variability and calibrate light curve data products. Templates, co-added groups of visits that act as an image of the "static" sky, are a key component of Difference Imaging Analysis (DIA) and as such are of paramount importance for all science that involves variable objects. As the "non-time-critical" science cases discussed here are mostly periodic, they generally do not depend upon the survey alert stream; however, templates are still crucial for performing science and calibrations during the first year. We provide recommendations for observing strategies for template acquisition starting from commissioning and through Year 1 of the survey

    Development and characterization of a large set of microsatellite markers for grape phylloxera (Daktulosphaira vitifoliae Fitch)

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    This study describes novel simple sequence repeat (SSR) primers from a genomic DNA sequence of the grape phylloxera. A total of 130 SSR primers were designed from 145 unique sequences with di, tri, tetra and penta simple sequence repeats. The SSR primers were tested on DNA from 10 grape phylloxera strains chosen for their behavioral and geographic diversity. Eightynine primers generated easy to score alleles with standardized  conditions of amplification. Twenty-eight new and four previously published markers were selected to genotype 32 root and leaf phylloxera samples in order to identify reliable markers for future genetic diversity and phylloxera population studies. SSR data from these samples was also used to determine the frequency of null alleles, and locus specific estimates of population differentiation and clustering. Up to six alleles were detected with a mean expected heterozygosity (He) of 0.51. The observed heterozygosity (Ho) was 0.73 and the majority of markers had higher Ho values. Null allees for four markers were considered to be the result of homozygous genotypes. The 89 SSR loci developed in this study represent a new and informative set of markers that are easy to combine for multi-loading and suitable for large-scale genetic analyses of population structure, genetic diversity, and the origin of host specific strains in grape phylloxera.

    Rational sequences for the conductance in quantum wires from affine Toda field theories

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    We analyse the expression for the conductance of a quantum wire which is decribed by an integrable quantum field theory. In the high temperature regime we derive a simple formula for the filling fraction. This expression involves only the inverse of a matrix which contains the information of the asymptotic phases of the scattering matrix and the solutions of the constant thermodynamic Bethe ansatz equations. Evaluating these expressions for minimal affine Toda field theory we recover several sequences of rational numbers, which are multiples of the famous Jain sequence for the filling fraction occurring in the context of the fractional quantum Hall effect. For instance we obtain ν=4m/(2m+1)\nu= 4 m/(2m +1) for A4m1A_{4m-1}-minimal affine Toda field theory. The matrices involved have in general non-rational entries and are not part of previous classification schemes based on integral lattices.Comment: 9 pages Latex, version to appear in Journal of Physics

    Photon number discrimination without a photon counter and its application to reconstructing non-Gaussian states

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    The non-linearity of a conditional photon-counting measurement can be used to `de-Gaussify' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement; unambiguously reconstructing the statistics of the non-Gaussian one and two photon subtracted squeezed vacuum states. Although our photon number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon number resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum information tasks relying on the outcomes of mean values.Comment: 4 pages, 3 figures. Theory section expanded in response to referee comment

    Systematic trends in beta-delayed particle emitting nuclei: The case of beta-p-alpha emission from 21Mg

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    We have observed beta+-delayed alpha and p-alpha emission from the proton-rich nucleus 21Mg produced at the ISOLDE facility at CERN. The assignments were cross-checked with a time distribution analysis. This is the third identified case of beta-p-alpha emission. We discuss the systematic of beta-delayed particle emission decays, show that our observed decays fit naturally into the existing pattern, and argue that the patterns are to a large extent caused by odd-even effects.Comment: 6 pages, 5 figure

    Food insecurity among people with severe mental disorder in a rural Ethiopian setting: a comparative, population-based study

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    Aim. In low-income African countries, ensuring food security for all segments of the population is a high priority. Mental illness is associated consistently with poverty, but there is little evidence regarding the association with food insecurity. The aim of this study was to compare the levels of food insecurity in people with severe mental disorders (SMD) with the general population in a rural African setting with a high burden of food insecurity. Method. Households of 292 community-ascertained people with a specialist-confirmed diagnosis of SMD (including schizophrenia and bipolar disorder) were compared with 284 households without a person with SMD in a rural district in south Ethiopia. At the time of the study, no mental health services were available within the district. Food insecurity was measured using a validated version of the Household Food Insecurity Access Scale. Disability was measured using the World Health Organisation Disability Assessment Schedule 2.0. Result. Severe household food insecurity was reported by 32.5% of people with SMD and 15.9% of respondents from comparison households: adjusted odds ratio 2.82 (95% confidence interval 1.62 to 4.91). Higher annual income was associated independently with lower odds of severe food insecurity. When total disability scores were added into the model, the association between SMD and food insecurity became non-significant, indicating a possible mediating role of disability. Conclusion. Efforts to alleviate food insecurity need to target people with SMD as a vulnerable group. Addressing the disabling effects of SMD would also be expected to reduce food insecurity. Access to mental health care integrated into primary care is being expanded in this district as part of the Programme for Improving Mental health carE (PRIME). The impact of treatment on disability and food insecurity will be evaluated
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