5,123 research outputs found

    Shoot organogenesis in leaf explants of Hydrangea macrophylla ‘Hyd1’ and assessing genetic stability of regenerants using ISSR markers

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    For the first time, an in vitro regeneration protocol of Hydrangea macrophylla 'Hyd1' was developed. Effects of different plant growth regulators (PGRs) on shoot regeneration were investigated jointly with selecting optimal basal media and cefotaxime concentrations. The highest frequency of shoot organogenesis (100%) and mean number of shoots per explant (2.7) were found on Gamborg B5 basal medium supplemented with 2.25 mg/l 6-benzyladenine (BA), 0.1 mg/l Indole-3-butyric acid (IBA), 100 mg/l cefotaxime and 30 g/l sucrose solidified by 7 g/l agar. Regenerated shoots were rooted by culturing on perlite plus half strength liquid B5 basal medium with 0.5 mg/l NAA. Rooted plantlets were transplanted to the greenhouse with 100% survival rate. Genetic stability of 32 plantlets (one mother plant and 31 regenerants) was assessed by 44 ISSR markers. Out of 44 ISSR markers, ten markers produced clear, reproducible bands with a mean of 5.9 bands per marker. The in vitro regeneration protocol is potentially useful for the genetic transformation of Hydrangea macrophylla 'Hyd1'

    Pressure in Chern-Simons Field Theory to Three-Loop Order

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    We calculate perturbatively the pressure of a dilute gas of anyons through second order in the anyon coupling constant, as described by Chern-Simons field theory. Near Bose statistics , the divergences in the perturbative expansion are exactly cancelled by a two-body δ\delta-function potential which is not required near Fermi statistics. To the order considered, we find no need for a non-hermitian Hamiltonian. (This paper precedes the article ''Three loop calculation of the full anyonic partition function'', by R. Emparan and M. Valle Basagoiti, hep-th/9304103)Comment: 10 pages, PlainTeX with macro manumac (included), report EHU-FT-92/

    Quark Effects in the Gluon Condensate Contribution to the Scalar Glueball Correlation Function

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    One-loop quark contributions to the dimension-four gluon condensate term in the operator product expansion (OPE) of the scalar glueball correlation function are calculated in the MS-bar scheme in the chiral limit of nfn_f quark flavours. The presence of quark effects is shown not to alter the cancellation of infrared (IR) singularities in the gluon condensate OPE coefficients. The dimension-four gluonic condensate term represents the leading power corrections to the scalar glueball correlator and, therein, the one-loop logarithmic contributions provide the most important condensate contribution to those QCD sum-rules independent of the low-energy theorem (the subtracted sum-rules).Comment: latex2e, 6 pages, 7 figures embedded in latex fil

    Semileptonic B decays into even parity charmed mesons

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    By using a constituent quark model we compute the form factors relevant to semileptonic transitions of B mesons into low-lying p-wave charmed mesons. We evaluate the q^2 dependence of these form factors and compare them with other model calculations. The Isgur-Wise functions tau(1/2) and tau(3/2) are also obtained in the heavy quark limit of our results.Comment: 11 pages, 2 figure

    A New Lower Bound on the Maximum Number of Satisfied Clauses in Max-SAT and its Algorithmic Applications

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    A pair of unit clauses is called conflicting if it is of the form (x)(x), (xˉ)(\bar{x}). A CNF formula is unit-conflict free (UCF) if it contains no pair of conflicting unit clauses. Lieberherr and Specker (J. ACM 28, 1981) showed that for each UCF CNF formula with mm clauses we can simultaneously satisfy at least \pp m clauses, where \pp =(\sqrt{5}-1)/2. We improve the Lieberherr-Specker bound by showing that for each UCF CNF formula FF with mm clauses we can find, in polynomial time, a subformula FF' with mm' clauses such that we can simultaneously satisfy at least \pp m+(1-\pp)m'+(2-3\pp)n"/2 clauses (in FF), where n"n" is the number of variables in FF which are not in FF'. We consider two parameterized versions of MAX-SAT, where the parameter is the number of satisfied clauses above the bounds m/2m/2 and m(51)/2m(\sqrt{5}-1)/2. The former bound is tight for general formulas, and the later is tight for UCF formulas. Mahajan and Raman (J. Algorithms 31, 1999) showed that every instance of the first parameterized problem can be transformed, in polynomial time, into an equivalent one with at most 6k+36k+3 variables and 10k10k clauses. We improve this to 4k4k variables and (25+4)k(2\sqrt{5}+4)k clauses. Mahajan and Raman conjectured that the second parameterized problem is fixed-parameter tractable (FPT). We show that the problem is indeed FPT by describing a polynomial-time algorithm that transforms any problem instance into an equivalent one with at most (7+35)k(7+3\sqrt{5})k variables. Our results are obtained using our improvement of the Lieberherr-Specker bound above

    Soybean Amino Acids in Health, Genetics, and Evaluation

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    Soybean is an important source of protein and amino acids for humans and livestock because of its well-balanced amino acid profile. This chapter outlines the strengths and weaknesses of soybean as a complete amino acid source as well as the relative importance of individual amino acids. Special attention is paid to the sulfur-containing amino acids, methionine and cysteine. Breeding and genetic engineering efforts are summarized to highlight previous accomplishments in amino acid improvement and potential avenues for future research. Agronomic properties and processing methods that affect amino acid levels in soybean food and feed are also explained. A brief introduction into current amino acid evaluation techniques is provided. By understanding the complexities of amino acids in soybean, protein quality for humans and livestock can be maximized

    ρ\rho Polarization and `Model Independent' Extraction of Vub/Vcd|V_{ub}|/|V_{cd}| from DρνD\to\rho\ell\nu and BρνB\to\rho\ell\nu

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    We briefly discuss the predictions of the heavy quark effective theory for the semileptonic decays of a heavy pseudoscalar to a light one, or to a light vector meson. We point out that measurement of combinations of differential helicity decay rates at Cleo-c and the BB factories can provide a model independent means of extracting the ratio Vub/Vcd|V_{ub}|/|V_{cd}|. We briefly discuss the corrections to this prediction.Comment: 8 pages, LaTeX, 1 figur

    Spin 3/2 Pentaquarks

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    We investigate the possible existence of the spin 3/2 pentaquark states using interpolating currents with K-N color-octet structure in the framework of QCD finite energy sum rule (FESR). We pay special attention to the convergence of the operator product expansion

    Equilibrium and nonequilibrium fluctuations at the interface between two fluid phases

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    We have performed small-angle light-scattering measurements of the static structure factor of a critical binary mixture undergoing diffusive partial remixing. An uncommon scattering geometry integrates the structure factor over the sample thickness, allowing different regions of the concentration profile to be probed simultaneously. Our experiment shows the existence of interface capillary waves throughout the macroscopic evolution to an equilibrium interface, and allows to derive the time evolution of surface tension. Interfacial properties are shown to attain their equilibrium values quickly compared to the system's macroscopic equilibration time.Comment: 10 pages, 5 figures, submitted to PR
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