583 research outputs found

    On estimation and identifiability issues of sex-linked inheritance with a case study of pigmentation in Swiss barn owl (Tyto alba)

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    Genetic evaluation using animal models or pedigree-based models generally assume only autosomal inheritance. Bayesian animal models provide a flexible framework for genetic evaluation, and we show how the model readily can accommodate situations where the trait of interest is influenced by both autosomal and sex-linked inheritance. This allows for simultaneous calculation of autosomal and sex-chromosomal additive genetic effects. Inferences were performed using integrated nested Laplace approximations (INLA), a nonsampling-based Bayesian inference methodology. We provide a detailed description of how to calculate the inverse of the X- or Z-chromosomal additive genetic relationship matrix, needed for inference. The case study of eumelanic spot diameter in a Swiss barn owl (Tyto alba) population shows that this trait is substantially influenced by variation in genes on the Z-chromosome (sigma(2)(z) = 0.2719 and sigma(2)(a) = 0.4405). Further, a simulation study for this study system shows that the animal model accounting for both autosomal and sex-chromosome-linked inheritance is identifiable, that is, the two effects can be distinguished, and provides accurate inference on the variance components

    Development of EM-CCD-based X-ray detector for synchrotron applications

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    A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved

    Multiplex systems for the amplification of short tandem repeat loci: Evaluation of laser fluorescence detection

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    Short tandem repeat (STR) loci are ideal markers for personal identification and for genomic mapping. Two fluorescent multiplex systems, each designed for simultaneous PCR amplification of four polymorphic STR loci (HUMCSF1PO, HUMTPOX, HUMTH01 and HUMVWFA31, and HUMF13A01, HUMFESFPS, HUMBFXIII and HUMLIPOL), were evaluated on three laser fluorescence detection instruments. Concordant DNA typing results were obtained with all three detection methods. These fluorescent multiplex STR systems offer an accurate, reproducible and versatile method of DNA profiling that is well-suited for forensic identity testing and other genetic analyses

    An Atom Laser Based on Raman Transitions

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    In this paper we present an atom laser scheme using a Raman transition for the output coupling of atoms. A beam of thermal atoms (bosons) in a metastable atomic state 1>|1 > are pumped into a multimode atomic cavity. This cavity is coupled through spontaneous emission to a single mode of another cavity for the ground atomic state, 2>|2 >. Above a certain threshold pumping rate a large number of atoms, N2N_2, builds up in this single quantum state and transitions to the ground state of the cavity become enhanced by a factor (N2+1)(N_2 + 1). Atoms in this state are then coupled to the outside of the cavity with a Raman transition. This changes the internal state of the atom and imparts a momentum kick, allowing the atoms to leave the system.Comment: 8 pages, 4 postscript figures, uses RevTex, home page at http://online.anu.edu.au/Physics/Welcome.html (Some aspects of the exact physical model have changed from original version. Other general improvements included

    Universality, vortices and confinement: modified SO(3) lattice gauge theory at non-zero temperature

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    We investigate the adjoint SU(2) lattice gauge theory in 3+1 dimensions with the Wilson plaquette action modified by a Z(2) monopole suppression term. For the zero-twist sector we report indications for the existence of a finite temperature effect decoupled from the unphysical bulk transitions.Comment: 17 pages, 10 figures. Some figures and text added. To appear on Phys. Rev.

    Leadership and the media: Gendered framings of Julia Gillard's ‘sexism and misogyny’ speech

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    This article analyses Australian media portrayals of former Australian Prime Minister Julia Gillard's ‘sexism and misogyny’ speech to parliament in October 2012. Our analysis reveals that coverage of the speech comprised three principal gendered framings: strategic attack, uncontrolled emotional outpouring and hypocrisy. We argue that these framings demonstrate the role the media plays as a gendered mediator, perpetuating the gender double bind that constrains female political leaders, as they negotiate the demand to demonstrate masculine leadership attributes without tarnishing the feminine qualities expected of them. In this instance, gendered media framings limited the saliency of Gillard's speech, curtailed calls for wider introspection on Australian political culture and further disassociated women from political leadership

    Effect of disorder on superconductivity in the boson-fermion model

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    We study how a randomness of either boson or fermion site energies affects the superconducting phase of the boson fermion model. We find that, contrary to what is expected for s-wave superconductors, the non-magnetic disorder is detrimental to the s-wave superconductivity. However, depending in which subsystem the disorder is located, we can observe different channels being affected. Weak disorder of the fermion subsystem is responsible mainly for renormalization of the single particle density of states while disorder in the boson subsystem directly leads to fluctuation of the strength of the effective pairing between fermions.Comment: 7 pages, 6 figures. Physical Review B (accepted for publication

    A particle-number-conserving Bogoliubov method which demonstrates the validity of the time-dependent Gross-Pitaevskii equation for a highly condensed Bose gas

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    The Bogoliubov method for the excitation spectrum of a Bose-condensed gas is generalized to apply to a gas with an exact large number N N of particles. This generalization yields a description of the Schr\"odinger picture field operators as the product of an annihilation operator AA for the total number of particles and the sum of a ``condensate wavefunction'' ξ(x)\xi(x) and a phonon field operator χ(x)\chi(x) in the form ψ(x)A{ξ(x)+χ(x)/N}\psi(x) \approx A\{\xi(x) + \chi(x)/\sqrt{N}\} when the field operator acts on the N particle subspace. It is then possible to expand the Hamiltonian in decreasing powers of N\sqrt{N}, an thus obtain solutions for eigenvalues and eigenstates as an asymptotic expansion of the same kind. It is also possible to compute all matrix elements of field operators between states of different N.Comment: RevTeX, 11 page
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