5,694 research outputs found

    The search for exudates from Eurasian watermilfoil and hydrilla

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    Secondary metabolites are produced by aquatic plants, and in some instances, exudation of these metabolites into the surrounding water has been detected. To determine whether infestations of Eurasian watermilfoil or hydrilla produce such exudates, plant tissues and water samples were collected from laboratory cultures and pond populations and were analyzed using solid phase extraction, HPLC, and various methods of mass spectrometry including electrospray ionization, GC/MS, electron impact and chemical ionization. Previously reported compounds such as tellimagrandin II (from Eurasian watermilfoil) and a caffeic acid ester (from hvdrilla), along with a newly discovered flavonoid, cyanidin 3 dimalonyl glucoside (from hydrilla), were readily detected in plant tissues used in this research but were not detected in any of the water samples. If compounds are being released, as suggested by researchers using axenic cultures, we hypothesize that they may be rapidly degraded by bacteria and therefore undetectable

    Current moments of 1D ASEP by duality

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    We consider the exponential moments of integrated currents of 1D asymmetric simple exclusion process using the duality found by Sch\"utz. For the ASEP on the infinite lattice we show that the nnth moment is reduced to the problem of the ASEP with less than or equal to nn particles.Comment: 13 pages, no figur

    Duality and Non-linear Response for Quantum Hall Systems

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    We derive the implications of particle-vortex duality for the electromagnetic response of Quantum Hall systems beyond the linear-response regime. This provides a first theoretical explanation of the remarkable duality which has been observed in the nonlinear regime for the electromagnetic response of Quantum Hall systems.Comment: 7 pages, 1 figure, typeset in LaTe

    Seagrass and marine resources in the Dugong protection areas of Upstart Bay, Newry Region, Sand Bay, Llewellyn Bay, Ince Bay and the Clairview Region, April/May 1999 and October 1999

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    The Marine Plant Ecology Group (Queensland Fisheries Service, Queensland Department of Primary Industries) was commissioned by the Great Barrier Reef Marine Park Authority to undertake two (one autumn and one spring) detailed seagrass surveys of the Dugong Protection Areas in Upstart Bay, Newry region, Sand Bay, Llewellyn Bay, Ince Bay, and a reconnaissance survey in the Clairview region. The information gathered from these surveys enhances the understanding and subsequent management of seagrass resources for fisheries and as dugong feeding habitats

    Preliminary evaluation of an acoustic technique for mapping tropical seagrass habitats

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    Seagrass meadows in Queensland are important nursery habitat for commercial species of penaeid prawns and fish. Seagrasses are essential food for dugong, Dugong dugon, and green sea turtles, Chelonia mydas (Linnaeus) and act as nutrient and sediment sinks. Seagrasses in coastal regions play important roles in maintaining sediment stability and water clarity. Coastal seagrass meadows are therefore an important resource economically and ecologically. Information on the species composition, abundance and distribution of seagrasses is used by management to zone for protection of seagrass habitats

    Anomalies on orbifolds with gauge symmetry breaking

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    We embed two 4D chiral multiplets of opposite representations in the 5D N=2 SU(N+K)SU(N+K) gauge theory compactified on an orbifold S1/(Z2×Z2)S^1/(Z_2\times Z'_2). There are two types of orbifold boundary conditions in the extra dimension to obtain the 4D N=1 SU(N)×SU(K)×U(1)SU(N)\times SU(K)\times U(1) gauge theory from the bulk: in Type I, one has the bulk gauge group at y=0y=0 and the unbroken gauge group at y=πR/2y=\pi R/2 while in Type II, one has the unbroken gauge group at both fixed points. In both types of orbifold boundary conditions, we consider the zero mode(s) as coming from a bulk (K+N)(K+N)-plet and brane fields at the fixed point(s) with the unbroken gauge group. We check the consistency of this embedding of fields by the localized anomalies and the localized FI terms. We show that the localized anomalies in Type I are cancelled exactly by the introduction of a bulk Chern-Simons term. On the other hand, in some class of Type II, the Chern-Simons term is not enough to cancel all localized anomalies even if they are globally vanishing. We also find that for the consistent embedding of brane fields, there appear only the localized log FI terms at the fixed point(s) with a U(1) factor.Comment: LaTeX file of 19 pages with no figure, published versio

    Self-Trapping, Quantum Tunneling and Decay Rates for a Bose Gas with Attractive Nonlocal Interaction

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    We study the Bose-Einstein condensation for a cloud of 7^7Li atoms with attractive nonlocal (finite-range) interaction in a harmonic trap. In addition to the low-density metastable branch, that is present also in the case of local interaction, a new stable branch appears at higher densities. For a large number of atoms, the size of the cloud in the stable high-density branch is independent of the trap size and the atoms are in a macroscopic quantum self-trapped configuration. We analyze the macroscopic quantum tunneling between the low-density metastable branch and the high-density one by using the istanton technique. Moreover we consider the decay rate of the Bose condensate due to inelastic two- and three-body collisions.Comment: 5 pages, 4 figures, submitted to Phys. Rev.
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