675 research outputs found
Comment on "Role of heavy meson exchange in near threshold N N --> d pi"
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
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
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
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
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
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
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
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
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