141 research outputs found

    ISSR-PCR for assessment of genetic relationships among grape varieties cultivated in India

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    Genetic relationships among 43 varieties cultivated in India were characterized using ISSR PCR. Out of total 139 reproducible fragments generated by 13 informative primers, 96 were polymorphic. The similarity coefficient ranged from 0.65 to 0.96. Cluster analysis resulted in the formation of two main clusters, consisting mainly of Vitis labrusca and V. vinifera types. One single variety belonging to V. rotundifolia James grouped with V. labrusca types but separated initially from them. Two varieties, Lake Emerald and Muscat, were completely outgrouped. Varieties belonging to V. vinifera appeared to be more diverse and separated further into many subgroups. In contrast, V. labrusca types were homogeneous. The results showed that ISSR is an efficient and reliable marker system for genetic analysis of grape cultivars

    Glueball Spectrum and Matrix Elements on Anisotropic Lattices

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    The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing ranging from 0.1fm - 0.2fm. These matrix elements are needed to predict the glueball branching ratios in J/ψJ/\psi radiative decays which will help identify the glueball states in experiments. Two types of improved local gluonic operators are constructed for a self-consistent check and the finite volume effects are studied. We find that lattice spacing dependence of our results is very weak and the continuum limits are reliably extrapolated, as a result of improvement of the lattice gauge action and local operators. We also give updated glueball masses with various quantum numbers.Comment: 22 pages, 16 figures, revtex

    Experimental Zika Virus Infection in the Pregnant Common Marmoset Induces Spontaneous Fetal Loss and Neurodevelopmental Abnormalities.

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    During its most recent outbreak across the Americas, Zika virus (ZIKV) was surprisingly shown to cause fetal loss and congenital malformations in acutely and chronically infected pregnant women. However, understanding the underlying pathogenesis of ZIKV congenital disease has been hampered by a lack of relevant in vivo experimental models. Here we present a candidate New World monkey model of ZIKV infection in pregnant marmosets that faithfully recapitulates human disease. ZIKV inoculation at the human-equivalent of early gestation caused an asymptomatic seroconversion, induction of type I/II interferon-associated genes and proinflammatory cytokines, and persistent viremia and viruria. Spontaneous pregnancy loss was observed 16-18 days post-infection, with extensive active placental viral replication and fetal neurocellular disorganization similar to that seen in humans. These findings underscore the key role of the placenta as a conduit for fetal infection, and demonstrate the utility of marmosets as a highly relevant model for studying congenital ZIKV disease and pregnancy loss

    A novel semi-fragile forensic watermarking scheme for remote sensing images

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    Peer-reviewedA semi-fragile watermarking scheme for multiple band images is presented. We propose to embed a mark into remote sensing images applying a tree structured vector quantization approach to the pixel signatures, instead of processing each band separately. The signature of themmultispectral or hyperspectral image is used to embed the mark in it order to detect any significant modification of the original image. The image is segmented into threedimensional blocks and a tree structured vector quantizer is built for each block. These trees are manipulated using an iterative algorithm until the resulting block satisfies a required criterion which establishes the embedded mark. The method is shown to be able to preserve the mark under lossy compression (above a given threshold) but, at the same time, it detects possibly forged blocks and their position in the whole image.Se presenta un esquema de marcas de agua semi-frágiles para múltiples imágenes de banda. Proponemos incorporar una marca en imágenes de detección remota, aplicando un enfoque de cuantización del vector de árbol estructurado con las definiciones de píxel, en lugar de procesar cada banda por separado. La firma de la imagen hiperespectral se utiliza para insertar la marca en el mismo orden para detectar cualquier modificación significativa de la imagen original. La imagen es segmentada en bloques tridimensionales y un cuantificador de vector de estructura de árbol se construye para cada bloque. Estos árboles son manipulados utilizando un algoritmo iteractivo hasta que el bloque resultante satisface un criterio necesario que establece la marca incrustada. El método se muestra para poder preservar la marca bajo compresión con pérdida (por encima de un umbral establecido) pero, al mismo tiempo, detecta posiblemente bloques forjados y su posición en la imagen entera.Es presenta un esquema de marques d'aigua semi-fràgils per a múltiples imatges de banda. Proposem incorporar una marca en imatges de detecció remota, aplicant un enfocament de quantització del vector d'arbre estructurat amb les definicions de píxel, en lloc de processar cada banda per separat. La signatura de la imatge hiperespectral s'utilitza per inserir la marca en el mateix ordre per detectar qualsevol modificació significativa de la imatge original. La imatge és segmentada en blocs tridimensionals i un quantificador de vector d'estructura d'arbre es construeix per a cada bloc. Aquests arbres són manipulats utilitzant un algoritme iteractiu fins que el bloc resultant satisfà un criteri necessari que estableix la marca incrustada. El mètode es mostra per poder preservar la marca sota compressió amb pèrdua (per sobre d'un llindar establert) però, al mateix temps, detecta possiblement blocs forjats i la seva posició en la imatge sencera

    A study of pentaquarks on the lattice with overlap fermions

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    We present a quenched lattice QCD calculation of spin-1/2 five-quark states with uuddsˉuudd\bar{s} quark content for both positive and negative parities. We do not observe any bound pentaquark state in these channels for either I = 0 or I =1. The states we found are consistent with KN scattering states which are checked to exhibit the expected volume dependence of the spectral weight. The results are based on overlap-fermion propagators on two lattices, 12^3 x 28 and 16^3 x 28, with the same lattice spacing of 0.2 fm, and pion mass as low as ~ 180 MeV.Comment: accepted for publication in Phys. Rev.

    Zero temperature string breaking in lattice quantum chromodynamics

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    The separation of a heavy quark and antiquark pair leads to the formation of a tube of flux, or "string", which should break in the presence of light quark-antiquark pairs. This expected zero-temperature phenomenon has proven elusive in simulations of lattice QCD. We study mixing between the string state and the two-meson decay channel in QCD with two flavors of dynamical sea quarks. We confirm that mixing is weak and find that it decreases at level crossing. While our study does not show direct effects of internal quark loops, our results, combined with unitarity, give clear confirmation of string breaking.Comment: 20 pages, 7 figures. With small clarifications and two additions to references. Submitted to Phys. Rev.

    Topological Susceptibility on Dynamical Staggered Fermion Configurations

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    The topological susceptibility is one of the few physical quantities that directly measure the properties of the QCD vacuum. Chiral perturbation theory predicts that in the small quark mass limit the topological susceptibility depends quadratically on the pion mass, approaching zero in the chiral limit. Lattice calculations have difficulty reproducing this behavior. In this paper we study the topological susceptibility on dynamical staggered fermion configurations. Our results indicate that the lattice spacing has to be small, around a~0.1fm for thin link staggered fermion actions to show the expected chiral behavior. Our preliminary result indicates that fat link fermions, on the other hand, reproduce the theoretical expectations even on lattices with a~0.17fm. We argue that this is due to the improved flavor symmetry of fat link fermionic actions.Comment: 16 pages, 4 figure
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