675 research outputs found

    Metabolism of n-hexadecane in myelinating rat brain

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    Comment on "Role of heavy meson exchange in near threshold N N --> d pi"

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    In a recent paper by C. J. Horowitz (Phys. Rev. C {\bf 48}, 2920 (1993)) a heavy meson exchange is incorporated into threshold NN --> d pi to enhance the grossly underestimated cross section. However, that calculation uses an unjustified assumption on the initial and final momenta, which causes an overestimate of this effect by a factor of 3--4. I point out that the inclusion of the Delta(1232) isobar increases the cross section significantly even at threshold.Comment: 7 pages, figures by fax or mail from [email protected]

    Statistical properties of thermodynamically predicted RNA secondary structures in viral genomes

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    By performing a comprehensive study on 1832 segments of 1212 complete genomes of viruses, we show that in viral genomes the hairpin structures of thermodynamically predicted RNA secondary structures are more abundant than expected under a simple random null hypothesis. The detected hairpin structures of RNA secondary structures are present both in coding and in noncoding regions for the four groups of viruses categorized as dsDNA, dsRNA, ssDNA and ssRNA. For all groups hairpin structures of RNA secondary structures are detected more frequently than expected for a random null hypothesis in noncoding rather than in coding regions. However, potential RNA secondary structures are also present in coding regions of dsDNA group. In fact we detect evolutionary conserved RNA secondary structures in conserved coding and noncoding regions of a large set of complete genomes of dsDNA herpesviruses.Comment: 9 pages, 2 figure

    An Empirical Analysis for Technical Efficiency of Bioenergy Industry in EU28 Region Based on Data Envelopment Analysis Method

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    Over the last few years concerns have enhanced about the bioenergy industry as main source for renewable and sustainable energy in many countries. These concerns have been major magnitude for countries with joint green energy legislation such as European Union (EU) member states. A significant aspect to be considered when selecting a provided bioenergy is the efficiency involved in its production. In this context, the current study analyzes the technical efficiency components in bioenergy industry in EU28 region between 1990 and 2013. To this end, parametric and non-parametric frontier models are applied, where both are particularly appropriate in this special context due to their treatment of undesirable outputs. Results are presenting higher means for technical efficiency and pure technical efficiency in developing countries in compare with developed countries. In the other hand, scale efficiency mean presenting high value in developed countries in compare with developing ones. Keywords: Bioenergy industry; technical efficiency; EU28 Region JEL Classifications: Q4, D6

    Positive pion absorption on 3He using modern trinucleon wave functions

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    We study pion absorption on 3He employing trinucleon wave functions calculated from modern realistic NN interactions (Paris, CD Bonn). Even though the use of the new wave functions leads to a significant improvement over older calculations with regard to both cross section and polarization data, there are hints that polarization data with quasifree kinematics cannot be described by just two-nucleon absorption mechanisms.Comment: 14 pages, 6 figure

    Nanoscale Processing by Adaptive Laser Pulses

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    We theoretically demonstrate that atomically-precise ``nanoscale processing" can be reproducibly performed by adaptive laser pulses. We present the new approach on the controlled welding of crossed carbon nanotubes, giving various metastable junctions of interest. Adaptive laser pulses could be also used in preparation of other hybrid nanostructures.Comment: 4 pages, 4 Postscript figure

    On spin-1 massive particles coupled to a Chern-Simons field

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    We study spin one particles interacting through a Chern-Simons field. In the Born approximation, we calculate the two body scattering amplitude considering three possible ways to introduce the interaction: (a) a Proca like model minimally coupled to a Chern-Simons field, (b) the model obtained from (a) by replacing the Proca's mass by a Chern-Simons term and (c) a complex Maxwell-Chern-Simons model minimally coupled to a Chern-Simons field. In the low energy regime the results show similarities with the Aharonov-Bohm scattering for spin 1/2 particles. We discuss the one loop renormalization program for the Proca's model. In spite of the bad ultraviolet behavior of the matter field propagator, we show that, up to one loop the model is power counting renormalizable thanks to the Ward identities satisfied by the interaction vertices.Comment: 14 pages, 5 figures, revte

    Modified differentials and basic cohomology for Riemannian foliations

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    We define a new version of the exterior derivative on the basic forms of a Riemannian foliation to obtain a new form of basic cohomology that satisfies Poincar\'e duality in the transversally orientable case. We use this twisted basic cohomology to show relationships between curvature, tautness, and vanishing of the basic Euler characteristic and basic signature.Comment: 20 pages, references added, minor corrections mad

    Study of a Depolarizing Resonance at the IUCF Cooler Ring

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478
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