4,205 research outputs found

    Spin dependent fragmentation function at Belle

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    The measurement of the so far unknown chiral-odd quark transverse spin distribution in either semi-inclusive DIS (SIDIS) or inclusive measurements in pp collisions at RHIC has an additional chiral-odd fragmentation function appearing in the cross section. These chiral-odd fragmentation functions (FF) can for example be the so-called Collins FF or the Interference FF. HERMES has given a first hint that these FFs are nonzero, however in order to measure the transversity one needs these FFs to be precisely known. We have used 29.0 fb1^{-1} of data collected by the Belle experiment at the KEKB e+ee^+e^- collider to measure azimuthal asymmetries for different charge combinations of pion pairs and thus access the Collins FF.Comment: Results presented at the DIS 2006 conference in Tsukuba, Japa

    The interaction-strength interpolation method for main-group chemistry: benchmarking, limitations, and perspectives

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    We have tested the original interaction-strength-interpolation (ISI) exchange-correlation functional for main group chemistry. The ISI functional is based on an interpolation between the weak and strong coupling limits and includes exact-exchange as well as the G\"orling-Levy second-order energy. We have analyzed in detail the basis-set dependence of the ISI functional, its dependence on the ground-state orbitals, and the influence of the size-consistency problem. We show and explain some of the expected limitations of the ISI functional (i.e. for atomization energies), but also unexpected results, such as the good performance for the interaction energy of dispersion-bonded complexes when the ISI correlation is used as a correction to Hartree-Fock.Comment: 20 pages, 20 figure

    Modelling bark beetle disturbances in a large scale forest scenario model to assess climate change impacts and evaluate adaptive management strategies

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    To study potential consequences of climate-induced changes in the biotic disturbance regime at regional to national scale we integrated a model of Ips typographus (L. Scol. Col.) damages into the large-scale forest scenario model EFISCEN. A two-stage multivariate statistical meta-model was used to upscale stand level damages by bark beetles as simulated in the hybrid forest patch model PICUS v1.41. Comparing EFISCEN simulations including the new bark beetle disturbance module against a 15-year damage time series for Austria showed good agreement at province level (R² between 0.496 and 0.802). A scenario analysis of climate change impacts on bark beetle-induced damages in Austria¿s Norway spruce [Picea abies (L.) Karst.] forests resulted in a strong increase in damages (from 1.33 Mm³ a¿1, period 1990¿2004, to 4.46 Mm³ a¿1, period 2095¿2099). Studying two adaptive management strategies (species change) revealed a considerable time-lag between the start of adaptation measures and a decrease in simulated damages by bark beetle

    C-terminal fusion of eGFP to the bradykinin B-2 receptor strongly affects down-regulation but not receptor internalization or signaling

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    A functional comparison was made between the wildtype bradykinin B, receptor (B(2)wt) and the chimera B(2)eGFP (enhanced green-fluorescent protein fused to the C-terminus of B(2)Wt), both stably expressed in HEK 293 cells. There was almost no difference in terms of ligand-inducible receptor phosphorylation and internalization, signal transduction (accumulation of inositol phosphates) or expression and affinity. However, stimulation for up to 8 h with 10 mu M bradykinin (BK) resulted in a strong decrease in surface receptors (by 60% within 5 h) in B(2)Wt, but not in B(2)eGFP. When the expression levels of both constructs where comparably reduced using a weaker promoter, long-term stimulation resulted in a reduction in surface receptors for B(2)wt(low) to less than 20% within 1 h, whereas the chimera B(2)eGFP(low) still displayed 50% binding activity after 2 h. A 1-h incubation in the absence of BK resulted in a recovery of 60% of the binding in B(2)wt(low) after 1-h stimulation with BK, but of only 20% after 7-h stimulation. In contrast, B(2)eGFP(low) levels were restored to more than 70%, even after 7-h stimulation. These data indicate that although the fusion of eGFP to B(2)wt does not affect its ligand-induced internalization, it strongly reduces the down-regulation, most likely by promoting receptor recycling over degradation

    Characterization and Commissioning of a Ka-Band Ground Station for Cognitive Algorithm Development

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    In 2018, the Cognitive Communications and Propagation projects completed installation and checkout testing of a new Ka-Band ground station at the NASA Glenn Research Center in Cleveland, Ohio. The Cognitive Algorithms Demonstration Testbed (CADeT) was developed to provide a fully characterized and controllable dynamic link environment to researchers looking to demonstrate hardware and software aligned with atmospheric sensing and cognitive algorithms. CADeT integrates a host of precision control and measurement systems in addition to repurposing a 5.5 meter beam-waveguide dish platform previously used with the Advanced Communications Technology Satellite (ACTS). This paper will discuss the laboratory testing of ground station components with a emphasis on elements vital to achieving link budget requirements including characterization of the new Gallium Nitride (GaN) Solid State Power Amplifier (SSPA) and far-field measurements of the new antenna feed. Finally, the paper discusses in-situ tests conducted with CADeT and the Tracking and Data Relay Satellite System (TDRSS) to validate laboratory results and make necessary link budget adjustments before reviewing the lessons learned

    High-frequency beam-plasma interaction at finite temperatures

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    High frequency beam plasma interaction at finite temperatur

    Decidability of the Monadic Shallow Linear First-Order Fragment with Straight Dismatching Constraints

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    The monadic shallow linear Horn fragment is well-known to be decidable and has many application, e.g., in security protocol analysis, tree automata, or abstraction refinement. It was a long standing open problem how to extend the fragment to the non-Horn case, preserving decidability, that would, e.g., enable to express non-determinism in protocols. We prove decidability of the non-Horn monadic shallow linear fragment via ordered resolution further extended with dismatching constraints and discuss some applications of the new decidable fragment.Comment: 29 pages, long version of CADE-26 pape

    Density functional theory for strongly-interacting electrons: Perspectives for Physics and Chemistry

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    Improving the accuracy and thus broadening the applicability of electronic density functional theory (DFT) is crucial to many research areas, from material science, to theoretical chemistry, biophysics and biochemistry. In the last three years, the mathematical structure of the strong-interaction limit of density functional theory has been uncovered, and exact information on this limit has started to become available. The aim of this paper is to give a perspective on how this new piece of exact information can be used to treat situations that are problematic for standard Kohn-Sham DFT. One way to use the strong-interaction limit, more relevant for solid-state physical devices, is to define a new framework to do practical, non-conventional, DFT calculations in which a strong-interacting reference system is used instead of the traditional non-interacting one of Kohn and Sham. Another way to proceed, more related to chemical applications, is to include the exact treatment of the strong-interaction limit into approximate exchange-correlation energy density functionals in order to describe difficult situations such as the breaking of the chemical bond. © 2010 the Owner Societies
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