3,116 research outputs found

    The Possible J^{PC}=0^{--} Exotic State

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    In order to explore the possible existence of the exotic 00^{--} state, we have constructed the tetraquark interpolating operators systematically. As a byproduct, we notice the 0+0^{+-} tetraquark operators without derivatives do not exist. The special Lorentz structure of the 00^{--} currents forbids the four-quark correction to the spectral density. Now the gluon condensate is the dominant power correction. Within the framework of the finite energy sum rule, none of the seven interpolating currents supports a resonant signal. Therefore we conclude that the exotic 00^{--} state does not exist below 2 GeV, which is consistent with the current experimental observations.Comment: 12 pages, 27 figure

    1H-Pyrazol-2-ium hydrogen oxalate

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    In the title compound, C3H5N2 +·C2HO4 −, the anions form centrosymmetric dimers through cyclic O—H⋯O hydrogen-bonding associations [graph set R 2 2(10)]. These dimers are then linked through a cyclic R 4 2(10) N—H⋯O hydrogen-bonding association involving two cations and the carboxyl O-atom acceptors of separate anions, giving chain structures extending across the (111) plane

    Quantum tunneling time of a Bose-Einstein condensate traversing through a laser-induced potential barrier

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    We theoretically study the effect of atomic nonlinearity on the tunneling time in the case of an atomic Bose-Einstein condensate (BEC) traversing the laser-induced potential barrier. The atomic nonlinearity is controlled to appear only in the region of the barrier by employing the Feshbach resonance technique to tune interatomic interaction in the tunneling process. Numerical simulation shows that the atomic nonlinear effect dramatically changes the tunneling behavior of the BEC matter wave packet, and results in the violation of Hartman effect and the occurrence of negative tunneling time.Comment: 4 pages, 5 figure

    Vinyl Ester Oligomer Crosslinked Porous Polymers Prepared via Surfactant-Free High Internal Phase Emulsions

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    Using vinyl ester resin (VER) containing styrene (or methyl methacrylate) and vinyl ester oligomer (VEO) as external phase, Pickering high internal phase emulsions (Pickering HIPEs) having internal phase volume fraction of up to 95 vol% were prepared with copolymer particles as sole stabilizer. Polymerizing the external phase of these Pickering HIPEs led to porous polymers (poly-Pickering-HIPEs). Compared to the polystyrene- (PS-) based poly-Pickering-HIPEs which were prepared with mixture of styrene and divinylbenzene (DVB) as crosslinker, the poly-Pickering-HIPEs herein showed much higher elastic modulus and toughness. The elastic modulus of these poly-Pickering-HIPEs increased with increasing the VEO concentration in the external phase, while it decreased with increasing internal phase volume fraction. Increasing VEO concentration in the external phase also resulted in a decrease in the average void diameter as well as a narrow void diameter distribution of the resulting poly-Pickering-HIPEs. In addition, there were many small pores in the voids surface caused by the volume contraction of VER during the polymerization, which suggests a new method to fabricate porous polymers having a well-defined hierarchical pore structure

    A genome scan for quantitative trait loci affecting growth-related traits in an F1 family of Asian seabass (Lates calcarifer)

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    BACKGROUND: Body weight and length are economically important traits in foodfish species influenced by quantitative trait loci (QTL) and environmental factors. It is usually difficult to dissect the genetic and environmental effects. Asian seabass (Lates calcarifer) is an important marine foodfish species with a compact genome (~700 Mb). The recent construction of a first generation linkage map of Asian seabass with 240 microsatellites provides a good opportunity to determine the number and position of QTL, and the magnitude of QTL effects with a genome scan. RESULTS: We conducted a genome scan for QTL affecting body weight, standard length and condition factors in an F1 family containing 380 full-sib individuals from a breeding stock by using 97 microsatellites evenly covering 24 chromosomes. Interval mapping and multiple QTL model mapping detected five significant and 27 suggestive QTL on ten linkage groups (LGs). Among the five significant QTL detected, three (qBW2-a, qTL2-a and qSL2-a) controlling body weight, total and standard length respectively, were mapped on the same region near Lca287 on LG2, and explained 28.8, 58.9 and 59.7% of the phenotypic variance. The other two QTL affecting body weight, qBW2-b and qBW3, were located on LG2 and 3, and accounted for 6.4 and 8.8% of the phenotypic variance. Suggestive QTL associated with condition factors are located on six different LGs. CONCLUSION: This study presents the first example of QTL detection for growth-related traits in an F1 family of a marine foodfish species. The results presented here will enable further fine-mapping of these QTL for marker-assisted selection of the Asian seabass, eventually identifying individual genes responsible for growth-related traits

    A simple and efficient method for isolating polymorphic microsatellites from cDNA

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    <p>Abstract</p> <p>Background</p> <p>Microsatellites in cDNA are useful as molecular markers because they represent transcribed genes and can be used as anchor markers for linkage and comparative mapping, as well as for studying genome evolution. Microsatellites in cDNA can be detected in existing ESTs by data mining. However, in most fish species, no ESTs are available or the number of ESTs is limited, although fishes represent half of the vertebrates on the earth. We developed a simple and efficient method for isolation of microsatellites from cDNA in fish.</p> <p>Results</p> <p>The method included normalization of 150 ng cDNA using 0.5 U duplex-specific nuclease (DSN) at 65°C for 30 min, enrichment of microsatellites using biotinylated oligonucleotides and magnetic field, and directional cloning of cDNA into a vector. We tested this method to enrich CA- and GA-microsatellites from cDNA of Asian seabass, and demonstrated that enrichment of microsatellites from normalized cDNA could increased the efficiency of microsatellite isolation over 30 times as compared to direct sequencing of clones from cDNA libraries. One hundred and thirty-nine (36.2%) out of 384 clones from normalized cDNA contained microsatellites. Unique microsatellite sequences accounted for 23.6% (91/384) of sequenced clones. Sixty microsatellites isolated from cDNA were characterized, and 41 were polymorphic. The average allele number of the 41 microsatellites was 4.85 ± 0.54, while the expected heterozygosity was 0.56 ± 0.03. All the isolated microsatellites inherited in a Mendelian pattern.</p> <p>Conclusion</p> <p>Normalization of cDNA substantially increased the efficiency of enrichment of microsatellites from cDNA. The described method for isolation of microsatellites from cDNA has the potential to be applied to a wide range of fish species. The microsatellites isolated from cDNA could be useful for linkage and comparative mapping, as well as for studying genome evolution.</p

    2-Ethyl­imidazolium terephthalate

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    The asymmetric unit of the title compound, C5H9N2 +·C8H5O4 −, consists of one protonated 2-ethyl­imidazolium cation and two half terephthalate anions. The anions and cations are linked through N—H⋯O hydrogen bonds while the anions are associated via O—H⋯O inter­actions, resulting in a layered structure. The ethyl group of the cation is disordered over twosites of occupancies 0.812 (14) and 0.188 (14). The hydroxy H atoms of the anions are equally disordered over two symmetry-related sites
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