Prefactor Reduction of the Guruswami-Sudan Interpolation Step

The concept of prefactors is considered in order to decrease the complexity of the Guruswami-Sudan interpolation step for generalized Reed-Solomon codes. It is shown that the well-known re-encoding projection due to Koetter et al. leads to one type of such prefactors. The new type of Sierpinski prefactors is introduced. The latter are based on the fact that many binomial coefficients in the Hasse derivative associated with the Guruswami-Sudan interpolation step are zero modulo the base field characteristic. It is shown that both types of prefactors can be combined and how arbitrary prefactors can be used to derive a reduced Guruswami-Sudan interpolation step.Comment: 13 pages, 3 figure

The Brown-Peterson spectrum is not E2(p2+2)E_{2(p^2+2)} at odd primes

Recently, Lawson has shown that the 2-primary Brown-Peterson spectrum does not admit the structure of an $E_{12}$ ring spectrum, thus answering a question of May in the negative. We extend Lawson's result to odd primes by proving that the p-primary Brown-Peterson spectrum does not admit the structure of an $E_{2(p^2+2)}$ ring spectrum. We also show that there can be no map $MU \to BP$ of $E_{2p+3}$ ring spectra at any prime.Comment: 21 pages, comments welcom

Probing dense QCD matter in the laboratory: The CBM experiment at FAIR

The Facility for Antiproton and Ion Research (FAIR) in Darmstadt will provide unique research opportunities for the investigation of fundamental open questions related to nuclear physics and astrophysics, including the exploration of QCD matter under extreme conditions, which governs the structure and dynamics of cosmic objects and phenomena like neutron stars, supernova explosions, and neutron star mergers. The physics program of the Compressed Baryonic Matter (CBM) experiment is devoted to the production and investigation of dense nuclear matter, with a focus on the high-density equation-of-state (EOS), and signatures for new phases of dense QCD matter. According to the present schedule, the CBM experiment will receive the first beams from the FAIR accelerators in 2025. This article reviews promising observables, outlines the CBM detector system, and presents results of physics performance studies.Comment: 16 pages, 13 figures. Physica Scripta 202

Strange mesons in dense nuclear matter

Experimental data on the production of kaons and antikaons in heavy ion collisions at relativistic energies are reviewed with respect to in-medium effects. The $K^-/K^+$ ratios measured in nucleus-nucleus collisions are 1 - 2 orders of magnitude larger than in proton-proton collisions. The azimuthal angle distributions of $K^+$ mesons indicate a repulsive kaon-nucleon potential. Microscopic transport calculations consistently explain both the yields and the emission patterns of kaons and antikaons when assuming that their properties are modified in dense nuclear matter. The $K^+$ production excitation functions measured in light and heavy collision systems provide evidence for a soft nuclear equation-of-state.Comment: 16 pages, 12 figures, Invited talk at the 7. international Conference Nucleus-Nucleus Collisions, Strasbourg, July 3-7, 200

First Principles Calculations of Spin-Dependent Conductance of Graphene Flakes

Using ab initio density functional theory and quantum transport calculations based on nonequilibrium Green's function formalism we study structural, electronic, and transport properties of hydrogen-terminated short graphene nanoribbons (graphene flakes) and their functionalization with vanadium atoms. Rectangular graphene flakes are stable, having geometric and electronic structures quite similar to that of extended graphene nanoribbons. We show that a spin-polarized current can be produced by pure, hydrogenated rectangular graphene flakes by exploiting the spatially-separated edge states of the flake using asymmetric, non-magnetic contacts. Functionalization of the graphene flake with magnetic adatoms such as vanadium also leads to spin-polarized currents even with symmetric contacts. We observe and discuss sharp discontinuities in the transmission spectra which arise from Fano resonances of localized states in the flake.Comment: 8 pages, 7 figures, 1 table. Phys. Rev. B 78, issue 20 (Accepted, in production); http://link.aps.org/doi/10.1103/PhysRevB.78.20542

Perception is Reality: Change Leadership and Work Engagement

Purpose The purpose of this paper is to investigate how employee perceptions of change and leadership might impact work engagement following major organizational change. Design/methodology/approach Social media invited US workers recently experiencing major organizational change to anonymously complete a web-based survey requesting qualitative and quantitative responses. Values-based coding and thematic analysis were used to explore qualitative data. Hierarchical and linear regression, and bootstrapped mediation were used to analyze quantitative data. Findings Analysis of qualitative data identified employees’ perceptions of ideal change and ideal leadership were well supported in the change leadership literature. Analysis of quantitative data indicated that employee perceptions of leadership fully mediated the relationship between employee perceptions of change and work engagement. Practical implications Study findings imply that how employees perceive change is explained by how they perceive leadership during change, and that these perceptions impact work engagement. Although these findings appear commonsensical, the less than stellar statistics on major organizational change may encourage leaders to become more follower-focused throughout the change process. Originality/value The study makes a contribution to an understudied area of organizational research, specifically applied information processing theory. This is the first study that identifies employee perceptions of leadership as a mediator for perceptions of change and work engagement. From a value perspective, leaders as successful change agents recognize significant cost savings in dollars and human welfare by maintaining healthy workplaces with highly engaged workers

Energy-transfer rate in a double-quantum-well system due to Coulomb coupling

We study the energy-transfer rate for electrons in a double-quantum-well structure, where the layers are coupled through screened Coulomb interactions. The energy-transfer rate between the layers (similar to the Coulomb drag effect in which the momentum transfer rate is considered) is calculated as functions of electron densities, interlayer spacing, the temperature difference of the 2DEGs, and the electron drift velocity in the drive layer. We employ the full wave vector and frequency dependent random-phase approximation at finite temperature to describe the effective interlayer Coulomb interaction. We find that the collective modes (plasmons) of the system play a dominant role in the energy transfer rates. The contribution of optical phonons to the transfer rates through the phonon mediated Coulomb coupling mechanism has also been considered.Comment: LaTex, 5 pages, 4 figures, uses grafik.sty (included