20,649 research outputs found

    Research Notes : A somatic approach to soybean genetics

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    For the past five years, our laboratory has been attempting to establish a system of somatic cell genetics for soybean. Although our results are far from complete, they are sufficiently encouraging to suggest that such a system will be practical and that it should be possible to construct a complete genetic. map within a few years. The rapidity with which this can be done relies in part on the somatic genetics discussed in this report and in part on a molecular genetic analysis which is now underway

    Shedding Light on the Off-Hours Coverage Gap in Radiology: Improving Turnaround Times and Critical Results Reporting

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    Objective: Devise a plan to optimize off-hours faculty and trainee staffing within the Department of Radiology Measure the magnitude of patient safety gains in terms of report turnaround times (TAT) and critical results communication times (CRC)https://jdc.jefferson.edu/patientsafetyposters/1044/thumbnail.jp

    Mixing-Demixing transition in 1D boson-fermion mixture at low fermion densities

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    We numerically investigated the mixing-demixing transition of the boson-fermion mixture on a 1D lattice at an incommensurate filling with the fermion density being kept below the boson density. The phase diagram we obtained suggested that the decrease of the number of the fermions drove the system into the demixing phase

    Creation of macroscopic superposition states from arrays of Bose-Einstein condensates

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    We consider how macroscopic quantum superpositions may be created from arrays of Bose-Einstein condensates. We study a system of three condensates in Fock states, all with the same number of atoms and show that this has the form of a highly entangled superposition of different quasi-momenta. We then show how, by partially releasing these condensates and detecting an interference pattern where they overlap, it is possible to create a macroscopic superposition of different relative phases for the remaining portions of the condensates. We discuss methods for confirming these superpositions.Comment: 7 pages, 5 figure

    Development of a hard X-ray split-and-delay line and performance simulations for two-color pump-probe experiments at the European XFEL

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    This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Review of Scientific Instruments 89, 063121 (2018) and may be found at https://doi.org/10.1063/1.5027071.A hard X-ray Split-and-Delay Line (SDL) under construction for the Materials Imaging and Dynamics station at the European X-Ray Free-Electron Laser (XFEL) is presented. This device aims at providing pairs of X-ray pulses with a variable time delay ranging from −10 ps to 800 ps in a photon energy range from 5 to 10 keV for photon correlation and X-ray pump-probe experiments. A custom designed mechanical motion system including active feedback control ensures that the high demands for stability and accuracy can be met and the design goals achieved. Using special radiation configurations of the European XFEL’s SASE-2 undulator (SASE: Self-Amplified Spontaneous Emission), two-color hard x-ray pump-probe schemes with varying photon energy separations have been proposed. Simulations indicate that more than 109 photons on the sample per pulse-pair and up to about 10% photon energy separation can be achieved in the hard X-ray region using the SDL.BMBF, 05K13KT4, Verbundprojekt FSP 302 - Freie-Elektronen-Laser: Nanoskopische Systeme. Teilprojekt 1: Split-and-Delay Instrument für die European XFEL Beamline Materials Imaging and DynamicsBMBF, 05K16BC1, Split-and-Delay Instrument für die European XFEL Beamline Materials Imaging and Dynamic

    Ultracold Bosonic Atoms in Disordered Optical Superlattices

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    The influence of disorder on ultracold atomic Bose gases in quasiperiodic optical lattices is discussed in the framework of the one-dimensional Bose-Hubbard model. It is shown that simple periodic modulations of the well depths generate a rich phase diagram consisting of superfluid, Mott insulator, Bose-glass and Anderson localized phases. The detailed evolution of mean occupation numbers and number fluctuations as function of modulation amplitude and interaction strength is discussed. Finally, the signatures of the different phases, especially of the Bose-glass phase, in matter-wave interference experiments are investigated.Comment: 4 pages, 4 figures, using REVTEX

    Group Strategyproof Pareto-Stable Marriage with Indifferences via the Generalized Assignment Game

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    We study the variant of the stable marriage problem in which the preferences of the agents are allowed to include indifferences. We present a mechanism for producing Pareto-stable matchings in stable marriage markets with indifferences that is group strategyproof for one side of the market. Our key technique involves modeling the stable marriage market as a generalized assignment game. We also show that our mechanism can be implemented efficiently. These results can be extended to the college admissions problem with indifferences

    Fermi-Bose quantum degenerate ^40 K - ^87 Rb mixture with attractive interaction

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    We report on the achievement of simultaneous quantum degeneracy in a mixed gas of fermionic ^40 K and bosonic ^87 Rb. Potassium is cooled to 0.3 times the Fermi temperature by means of an efficient thermalization with evaporatively cooled rubidium. Direct measurement of the collisional cross-section confirms a large interspecies attraction. This interaction is shown to affect the expansion of the Bose-Einstein condensate released form the magnetic trap, where it is immersed in the Fermi sea.Comment: 5 pages, 4 figures, replaced one figure plus some change

    A Quantum Monte Carlo Method and Its Applications to Multi-Orbital Hubbard Models

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    We present a framework of an auxiliary field quantum Monte Carlo (QMC) method for multi-orbital Hubbard models. Our formulation can be applied to a Hamiltonian which includes terms for on-site Coulomb interaction for both intra- and inter-orbitals, intra-site exchange interaction and energy differences between orbitals. Based on our framework, we point out possible ways to investigate various phase transitions such as metal-insulator, magnetic and orbital order-disorder transitions without the minus sign problem. As an application, a two-band model is investigated by the projection QMC method and the ground state properties of this model are presented.Comment: 10 pages LaTeX including 2 PS figures, to appear in J.Phys.Soc.Jp
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