1,520 research outputs found

    Scoping current and future genetic tools, their limitations and their applications for wild fisheries management

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    The overarching goal of this project was to prepare a document that summarises past, present and emerging ways in which research using genetic technology can assist the Australian fishing industry to maintain productive and sustainable harvests. The project achieved the following specific objectives: 1. Documented existing and prospective biotechnologies and genetic analysis tools that are relevant to wild fisheries management, and their availability and application at a national and international level; 2. Documented the FRDC’s past and current investment in biotechnology and genetic tools used in wild fisheries management research; 3. Documented the different biotechnology and genetic tools that are being used in wild fisheries management research in Australia, and the nature and location of key research groups; 4. Described what management question each tool has been used for (e.g. stock structure, biomass estimation, product provenance, disease monitoring); 5. Identified those tools and approaches (existing and future) most likely to deliver significant advances in fisheries management; 6. Identified the potential for collaborations which could improve the focus and impact of work in this area

    Quantum pumping and dissipation: from closed to open systems

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    Current can be pumped through a closed system by changing parameters (or fields) in time. The Kubo formula allows to distinguish between dissipative and non-dissipative contributions to the current. We obtain a Green function expression and an SS matrix formula for the associated terms in the generalized conductance matrix: the "geometric magnetism" term that corresponds to adiabatic transport; and the "Fermi golden rule" term which is responsible to the irreversible absorption of energy. We explain the subtle limit of an infinite system, and demonstrate the consistency with the formulas by Landauer and Buttiker, Pretre and Thomas. We also discuss the generalization of the fluctuation-dissipation relation, and the implications of the Onsager reciprocity.Comment: 4 page paper, 1 figure (published version) + 2 page appendi

    A generalized model for fuel channel bore estimation in AGR cores

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    One of the major life-limiting factors of an Advanced Gas-cooled Reactor (AGR) nuclear power station is the graphite core as it cannot be repaired or replaced and therefore detailed information about the health of the core is vital for continued safe operation. The graphite bricks that comprise the core experience gradual degradation during operation as a result of irradiation. Routine physical inspection of the graphite core fuel channels is performed by specialist inspection equipment during outages every 12 months to 3 years. It has also been shown to be advantageous to supplement this periodic inspection information with analysis of operational data which can provide additional insights into the core health. One such approach is through the use of online monitoring data called the Fuel Grab Load Trace (FGLT). An FGLT is a measure of the perceived load of the fuel assembly with contributions from aerodynamic forces and frictional forces, which is related to bore diameter. This paper describes enhancements to existing analysis of FGLT data which, to date, has focussed solely on using data from a single reactor at a time to build bore estimation models, by considering data from multiple reactors to produce a generalised model of bore estimation. This paper initially describes the process of producing a bore estimation from an FGLT by isolating the contribution that relates to the fuel channel bore and then discusses the limitations with the existing bore estimation model. Improvements are then proposed for the bore estimation model and a detailed assessment is undertaken to understand the effect of each of these proposed improvements. In addition, the effect of introducing non-linear regression models to further enhance the bore estimation is explored. The existing model is trained on data from one reactor in the UK and therefore the results produced from it are only applicable to this reactor. However, out of the remaining 13 nuclear reactors currently in operation, 3 also have a similar construction to the reactor the model is trained on, and these should all produce similar FGLT data. Therefore, a generalised model is proposed that produces bore estimations for four AGRs station’s reactors, compared with one previously. It is shown that this approach offers an improved overall bore estimation model

    On Probabilistic Applicative Bisimulation and Call-by-Value λ\lambda-Calculi (Long Version)

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    Probabilistic applicative bisimulation is a recently introduced coinductive methodology for program equivalence in a probabilistic, higher-order, setting. In this paper, the technique is applied to a typed, call-by-value, lambda-calculus. Surprisingly, the obtained relation coincides with context equivalence, contrary to what happens when call-by-name evaluation is considered. Even more surprisingly, full-abstraction only holds in a symmetric setting.Comment: 30 page

    Classical and quantum pumping in closed systems

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    Pumping of charge (Q) in a closed ring geometry is not quantized even in the strict adiabatic limit. The deviation form exact quantization can be related to the Thouless conductance. We use Kubo formalism as a starting point for the calculation of both the dissipative and the adiabatic contributions to Q. As an application we bring examples for classical dissipative pumping, classical adiabatic pumping, and in particular we make an explicit calculation for quantum pumping in case of the simplest pumping device, which is a 3 site lattice model.Comment: 5 pages, 3 figures. The long published version is cond-mat/0307619. This is the short unpublished versio

    Measuring Pancharatnam's relative phase for SO(3) evolutions using spin polarimetry

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    In polarimetry, a superposition of internal quantal states is exposed to a single Hamiltonian and information about the evolution of the quantal states is inferred from projection measurements on the final superposition. In this framework, we here extend the polarimetric test of Pancharatnam's relative phase for spin1/2-{1/2} proposed by Wagh and Rakhecha [Phys. Lett. A {\bf 197}, 112 (1995)] to spin j1j\geq 1 undergoing noncyclic SO(3) evolution. We demonstrate that the output intensity for higher spin values is a polynomial function of the corresponding spin1/2-{1/2} intensity. We further propose a general method to extract the noncyclic SO(3) phase and visibility by rigid translation of two π/2\pi /2 spin flippers. Polarimetry on higher spin states may in practice be done with spin polarized atomic beams.Comment: New title, minor corrections, journal reference adde

    Washington Park Main Street Plan

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    There is an immense variety of privately owned businesses. They will be stakeholders because their businesses are located there, but they will also be assets in themselves in drawing people to the area. There is basically everything anyone could possible want or need in this area. There are two gas stations, a Family Dollar, a liquor store, a few sit down restaurants, numerous places where one can get a quick bite to eat, a frame shop, a clothing store, a pawn shop, a store with fresh produce (which is hard to find in urban areas), a store that sells sports uniforms, a frame shop, a lawyerʼs office, an animal hospital, two Laundromats, a record shop, a health food store, two cell phone stores, an automotive shop, and a karate school with an afterschool program. With such variety, it will draw people to the area and then give them other reasons to keep coming back

    Adiabatic response for Lindblad dynamics

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    We study the adiabatic response of open systems governed by Lindblad evolutions. In such systems, there is an ambiguity in the assignment of observables to fluxes (rates) such as velocities and currents. For the appropriate notion of flux, the formulas for the transport coefficients are simple and explicit and are governed by the parallel transport on the manifold of instantaneous stationary states. Among our results we show that the response coefficients of open systems, whose stationary states are projections, is given by the adiabatic curvature.Comment: 33 pages, 4 figures, accepted versio

    Statistical analysis and the equivalent of a Thouless energy in lattice QCD Dirac spectra

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    Random Matrix Theory (RMT) is a powerful statistical tool to model spectral fluctuations. This approach has also found fruitful application in Quantum Chromodynamics (QCD). Importantly, RMT provides very efficient means to separate different scales in the spectral fluctuations. We try to identify the equivalent of a Thouless energy in complete spectra of the QCD Dirac operator for staggered fermions from SU(2) lattice gauge theory for different lattice size and gauge couplings. In disordered systems, the Thouless energy sets the universal scale for which RMT applies. This relates to recent theoretical studies which suggest a strong analogy between QCD and disordered systems. The wealth of data allows us to analyze several statistical measures in the bulk of the spectrum with high quality. We find deviations which allows us to give an estimate for this universal scale. Other deviations than these are seen whose possible origin is discussed. Moreover, we work out higher order correlators as well, in particular three--point correlation functions.Comment: 24 pages, 24 figures, all included except one figure, missing eps file available at http://pluto.mpi-hd.mpg.de/~wilke/diff3.eps.gz, revised version, to appear in PRD, minor modifications and corrected typos, Fig.4 revise

    Iordanskii Force and the Gravitational Aharonov-Bohm effect for a Moving Vortex

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    I discuss the scattering of phonons by a vortex moving with respect to a superfluid condensate. This allows us to test the compatibility of the scattering-theory derivation of the Iordanskii force with the galilean invariance of the underlying fluid dynamics. In order to obtain the correct result we must retain O(vs2)O(v_s^2) terms in the sound-wave equation, and this reinforces the interpretation, due to Volovik, of the Iordanskii force as an analogue of the gravitational Bohm-Aharonov effect.Comment: 20 pages, LaTe
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