2,111 research outputs found

    White paper: A plan for cooperation between NASA and DARPA to establish a center for advanced architectures

    Get PDF
    Large, complex computer systems require many years of development. It is recognized that large scale systems are unlikely to be delivered in useful condition unless users are intimately involved throughout the design process. A mechanism is described that will involve users in the design of advanced computing systems and will accelerate the insertion of new systems into scientific research. This mechanism is embodied in a facility called the Center for Advanced Architectures (CAA). CAA would be a division of RIACS (Research Institute for Advanced Computer Science) and would receive its technical direction from a Scientific Advisory Board established by RIACS. The CAA described here is a possible implementation of a center envisaged in a proposed cooperation between NASA and DARPA

    Magnet Laboratory Research

    Get PDF
    Contains reports on five research projects.United States Atomic Energy Commission (Contract AT(30-1)-1283

    Radio-Frequency Spectroscopy

    Get PDF
    Contains reports on four research projects

    Low-Temperature Physics

    Get PDF
    Contains reports on five research projects

    Effective Symmetries of the Minimal Supermultiplet of N = 8 Extended Worldline Supersymmetry

    Full text link
    A minimal representation of the N = 8 extended worldline supersymmetry, known as the `ultra-multiplet', is closely related to a family of supermultiplets with the same, E(8) chromotopology. We catalogue their effective symmetries and find a Spin(4) x Z(2) subgroup common to them all, which explains the particular basis used in the original construction. We specify a constrained superfield representation of the supermultiplets in the ultra-multiplet family, and show that such a superfield representation in fact exists for all adinkraic supermultiplets. We also exhibit the correspondences between these supermultiplets, their Adinkras and the E(8) root lattice bases. Finally, we construct quadratic Lagrangians that provide the standard kinetic terms and afford a mixing of an even number of such supermultiplets controlled by a coupling to an external 2-form of fluxes.Comment: 13 Figure

    Radio-Frequency Spectroscopy

    Get PDF
    Contains reports on three research projects

    Linking integrative plant physiology with agronomy to sustain future plant production

    Get PDF
    Sustainable production of high-quality food is one of today's major challenges of agriculture. To achieve this goal, a better understanding of plant physiological processes and a more integrated approach with respect to current agronomical practices are needed. In this review, various examples of cooperation between integrative plant physiology and agronomy are discussed, and this demonstrates the complexity of these interrelations. The examples are meant to stimulate discussions on how both research areas can deliver solutions to avoid looming food crises due to population growth and climate change. In the last decades, unprecedented progress has been made in the understanding of how plants grow and develop in a variety of environments and in response to biotic stresses, but appropriate management and interpretation of the resulting complex datasets remains challenging. After providing an historical overview of integrative plant physiology, we discuss possible avenues of integration, involving advances in integrative plant physiology, to sustain plant production in the current post-omics era. Finally, recommendations are provided on how to practice the transdisciplinary mindset required, emphasising a broader approach to sustainable production of high-quality food in the future, whereby all those who are involved are made partners in knowledge generation processes through transdisciplinary cooperation. © 2020 Elsevier B.V

    Electronic States and Magnetic Propertis of Edge-sharing Cu-O Chains

    Full text link
    The electronic states and magnetic properties for the copper oxides containing edge-sharing Cu-O chains such as Li2_2CuO2_2, La6_6Ca8_8Cu24_{24}O41_{41} and CuGeO3_3 are systematically studied. The optical conductivity σ(ω)\sigma(\omega) and the temperature dependence of the magnetic susceptibility χ(T)\chi(T) for single crystalline samples Li2_2CuO2_2 are measured as a reference system and analyzed by using the exact diagonalization method for small Cu-O clusters. It is shown that the spectral distribution of σ(ω)\sigma(\omega) is different between edge-sharing and corner-sharing Cu-O-Cu bonds. The charge transfer gap in edge-sharing chains is larger than that of high-TcT_{c} cuprates. The exchange interaction between nearest-neighbor copper ions in edge-sharing chains J1J_1 depends sensitively on the Cu-O-Cu bond angles. In addition to J1J_1, the exchange interaction between next-nearest-neighbor copper ions J2J_2 has sufficient contribution to the magnetic properties. We calculate J1J_1 and J2J_2 for all the copper oxides containing edge-sharing Cu-O chains and discuss the magnetic properties.Comment: 10 pages,RevTeX,8 postscript figures. Accepted for publication in Phys. Rev.

    Inflation with Ω1\Omega \not = 1

    Full text link
    We discuss various models of inflationary universe with Ω1\Omega \not = 1. A homogeneous universe with Ω>1\Omega > 1 may appear due to creation of the universe "from nothing" in the theories where the effective potential becomes very steep at large ϕ\phi, or in the theories where the inflaton field ϕ\phi nonminimally couples to gravity. Inflation with Ω<1\Omega < 1 generally requires intermediate first order phase transition with the bubble formation, and with a second stage of inflation inside the bubble. It is possible to realize this scenario in the context of a theory of one scalar field, but typically it requires artificially bent effective potentials and/or nonminimal kinetic terms. It is much easier to obtain an open universe in the models involving two scalar fields. However, these models have their own specific problems. We propose three different models of this type which can describe an open homogeneous inflationary universe.Comment: 29 pages, LaTeX, parameters of one of the models are slightly modifie
    corecore