49,330 research outputs found

    Attraction of migratory inanga (galaxias maculatus) and koaro (galaxias brevipinnis) juveniles to adult galaxiid odours

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    The response of migratory galaxiid juveniles, inanga (Galaxias maculatus) and koaro (G. brevipinnis), to the odours of adult galaxiids was tested in a two-choice chamber apparatus. Both conspecific and heterospecific odours were tested. Inanga juveniles were attracted to adult inanga (G. maculatus), banded kokopu (G. fasciatus), and koaro (G. brevipinnis) odours. However, they were not attracted to odours from common bullies (Gobiomorphus cotidianus). Koaro juveniles exhibited a species-specific attraction to adult koaro odours only. These results demonstrate inanga uveniles can discriminate and are attracted to adult galaxiids during their migratory phase, whilst migratory koaro juveniles exhibit a species-specific attraction to adult odours similar to the pheromonal attraction previously described for juvenile banded kokopu. This strengthens the hypothesis for the use of pheromonal cues in stream and habitat selection by amphidromous galaxiids

    Chiral-symmetry breaking in dual QCD

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    In the context of the formulation of QCD with dual potentials, we show that chiral-symmetry breaking occurs only in the confined state. Therefore, the transition temperature, beyond which chiral symmetry is restored, is the same as the deconfinement temperature. To carry out the calculation, it is necessary to couple quarks to dual gluons. We indicate how this is done (to lowest order in the magnetic coupling constant) and give the Feynman rules for quark–dual-gluon vertices

    Static quark potential according to the dual-superconductor picture of QCD

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    We use the effective action describing long-range QCD, which predicts that QCD behaves as a dual superconductor, to derive the interaction energy between two heavy quarks as a function of separation. The dual-superconductor field equations are solved in an approximation in which the boundary between the superconducting vacuum and the region of normal vacuum surrounding the quarks is sharp. Further, non-Abelian effects are neglected. The resulting heavy-quark potential is linear in separation at large separation, and Coulomb-like at small separation. Overall it agrees very well with phenomenologically determined potentials

    Quantized electric-flux-tube solutions to Yang-Mills theory

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    We suggest that long-distance Yang-Mills theory is more conveniently described in terms of electric rather than the customary magnetic vector potentials. On this basis we propose as an effective Lagrangian for this regime the most simple gauge-invariant (under the magnetic rather than electric gauge group) and Lorentz-invariant Lagrangian which yields a 1/q^4 gluon propagator in the Abelian limit. The resulting classical equations of motion have solutions corresponding to tubes of color electric flux quantized in units of e/2 (e is the Yang-Mills coupling constant). To exponential accuracy the electric color energy is contained in a cylinder of finite radius, showing that continuum Yang-Mills theory has excitations which are confined tubes of color electric flux. This is the criterion for electric confinement of color

    A Constituent Quark Anti-Quark Effective Lagrangian Based on the Dual Superconducting Model of Long Distance QCD

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    We review the assumptions leading to the description of long distance QCD by a Lagrangian density expressed in terms of dual potentials. We find the color field distribution surrounding a quark anti-quark pair to first order in their velocities. Using these distributions we eliminate the dual potentials from the Lagrangian density and obtain an effective interaction Lagrangian LI(x⃗1 ,x⃗2 ;v⃗1 ,v⃗2)L_I ( \vec x_1 \, , \vec x_2 \, ; \vec v_1 \, , \vec v_2 ) depending only upon the quark and anti-quark coordinates and velocities, valid to second order in their velocities. We propose LIL_I as the Lagrangian describing the long distance interaction between constituent quarks. Elsewhere we have determined the two free parameters in LIL_I, αs\alpha_s and the string tension σ\sigma, by fitting the 17 known levels of bbˉb \bar b and ccˉc \bar c systems. Here we use LIL_I at the classical level to calculate the leading Regge trajectory. We obtain a trajectory which becomes linear at large M2M^2 with a slope αâ€Č≃.74 GeV−1\alpha' \simeq .74 \, \hbox{GeV}^{-1}, and for small M2M^2 the trajectory bends so that there are no tachyons. For a constituent quark mass between 100 and 150 MeV this trajectory passes through the two known Regge recurrences of the π\pi meson. In this paper, for simplicity of presentation, we have treated the quarks as spin-zero particles.Comment: {\bf 32,UW/PT94-0

    Interaction between solitons in gauge theories

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    A systematic method for obtaining asymptotic multisoliton solutions in gauge theories is given. These solutions are used to investigate the interaction between vortex lines in type-I and type-II superconductors, reproducing the known behavior. The application to QCD flux tubes and glueballs obtained from the long-range effective Lagrangian yield the following results: (1) No long-range Van der Waals–type forces exist between these solitons in spite of the fact that the Abelian force law obtained from this model is a linear potential; (2) the interactions between flux tubes and between flux tubes and anti-flux-tubes are identical, being repulsive at long range and strongly attractive at short range. This behavior differs sharply from the superconductor case, and results from the differences between the gauge groups SU(2) and U(1)

    The mass of the black hole in LMC X-3

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    New high resolution, optical spectroscopy of the high mass X-ray binary LMC X-3, shows the spectral type of the donor star changes with phase due to irradition by the X-ray source. We find the spectral type is likely to be B5V, and only appears as B3V when viewing the heated side of the donor. Combining our measurements with those previously published, and taking into account the effects of X-ray irradiation, results in a value for the donor star radial velocity semi-amplitude of Ko=256.7±4.9K_{o} = 256.7 \pm 4.9~km~s−1^{-1}. We find the mass of the black hole lies in the range 9.5M⊙≀Mx≀13.6M⊙9.5M_{\odot} \leq M_{\rm x} \leq 13.6M_{\odot}

    Wegner estimate for discrete alloy-type models

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    We study discrete alloy-type random Schr\"odinger operators on ℓ2(Zd)\ell^2(\mathbb{Z}^d). Wegner estimates are bounds on the average number of eigenvalues in an energy interval of finite box restrictions of these types of operators. If the single site potential is compactly supported and the distribution of the coupling constant is of bounded variation a Wegner estimate holds. The bound is polynomial in the volume of the box and thus applicable as an ingredient for a localisation proof via multiscale analysis.Comment: Accepted for publication in AHP. For an earlier version see http://www.ma.utexas.edu/mp_arc-bin/mpa?yn=09-10
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