395 research outputs found
White sorghum grain (Funk\u27s G766W) and elevator-run red sorghum grain compared for fattening cattle
An new white variety of sorghum grain (Funk\u27s G766W) has been reported to be higher in digestible dry matter and protein than elevator-run, rod sorghum grain. A 120-day field trial was conducted on the George and Vernon Miller farm near Great Bend to compare the two sorghum grain types under feed-lot conditions
Searching Data: A Review of Observational Data Retrieval Practices in Selected Disciplines
A cross-disciplinary examination of the user behaviours involved in seeking
and evaluating data is surprisingly absent from the research data discussion.
This review explores the data retrieval literature to identify commonalities in
how users search for and evaluate observational research data. Two analytical
frameworks rooted in information retrieval and science technology studies are
used to identify key similarities in practices as a first step toward
developing a model describing data retrieval
Pathogenesis of Bovine Herpesviruses in vitro
Bovine herpesviruses cause acute disease in cattle. Bovine herpesvirus 1 (BHV-1 or IBR) is a respiratory virus, while bovine herpesvirus 5 (BHV-5) affects the brain and causes a viral encephalitis. Studies in the laboratory showed no difference in the growth rate of BHV-1 or BHV-5 in blood vessel, brain, or kidney cells. The ability of BHV-1 to cause cells to die is not caused by apoptosis (programmed cell death). Further studies on the pathogenesis of bovine herpesviruses need to be conducted to improve control and prevention measures
Hyperons analogous to the \Lambda(1405)
The low mass of the hyperon with , which is
higher than the ground state mass by 290 MeV, is difficult to
understand in quark models. We analyze the hyperon spectrum in the bound state
approach of the Skyrme model that successfully describes both the
and the . This model predicts that several
hyperon resonances of the same spin but with opposite parity form parity
doublets that have a mass difference of around 300 MeV, which is indeed
realized in the observed hyperon spectrum. Furthermore, the existence of the
and the of is predicted by this model.
Comments on the baryons and heavy quark baryons are made as well.Comment: 4 pages, talk presented at the Fifth Asia-Pacific Conference on
Few-Body Problems in Physics 2011 (APFB2011), Aug. 22-26, 2011, Seoul, Kore
Excited Baryon Decay Widths in Large N_c QCD
We study excited baryon decay widths in large N_c QCD. It was suggested
previously that some spin-flavor mixed-symmetric baryon states have strong
couplings of O(N_c^{-1/2}) to nucleons [implying narrow widths of O(1/N_c)], as
opposed to the generic expectation based on Witten's counting rules of an
O(N_c^0) coupling. The calculation obtaining these narrow widths was performed
in the context of a simple quark-shell model. This paper addresses the question
of whether the existence of such narrow states is a general property of large
N_c QCD. We show that a general large N_c QCD analysis does not predict such
narrow states; rather they are a consequence of the extreme simplicity of the
quark model.Comment: 9 page
Excited Baryons in Large N_c QCD Revisited: The Resonance Picture Versus Single-Quark Excitations
We analyze excited baryon properties via a 1/N_c expansion from two
perspectives: as resonances in meson-nucleon scattering, and as single-quark
excitations in the context of a simple quark model. For both types of analysis
one can derive novel patterns of degeneracy that emerge as N_c --> \infty, and
that are shown to be compatible with one another. This helps justify the
single-quark excitation picture and may give some insight into its successes.
We also find that in the large N_c limit one of the S_{11} baryons does not
couple to the pi-N channel but couples to the eta-N channel. This is
empirically observed in the N(1535), which couples very weakly to the pi-N
channel and quite strongly to the eta-N channel. The comparatively strong
coupling of the N(1650) to the pi-N channel and weak coupling to eta-N channel
is also predicted. In the context of the simple quark model picture we
reproduce expressions for mixing angles that are accurate up to O(1/N_c)
corrections and are in good agreement with mixing angles extracted
phenomenologically.Comment: 13 pages, ReVTeX
Global and consistent analysis of the heavy-ion elastic scattering and fusion processes
We have developed a model for the nuclear interaction which is based on the effects of the Pauli nonlocality.
In earlier works, we have successfully used this interaction to describe the elastic scattering for several systems
in a very wide energy range. In the present work, we have checked the validity of the same interaction in the
description of about 2500 fusion cross section data for 165 different systems. By introducing only one energyand
system-independent effective parameter, the nonlocal model describes the global behavior of the fusion
process with good precision
Negative Parity 70-plet Baryon Masses in the 1/Nc Expansion
The masses of the negative parity SU(6) 70-plet baryons are analyzed in the
1/Nc expansion to order 1/Nc and to first order in SU(3) breaking. At this
level of precision there are twenty predictions. Among them there are the well
known Gell-Mann Okubo and equal spacing relations, and four new relations
involving SU(3) breaking splittings in different SU(3) multiplets. Although the
breaking of SU(6) symmetry occurs at zeroth order in 1/Nc, it turns out to be
small. The dominant source of the breaking is the hyperfine interaction which
is of order 1/Nc. The spin-orbit interaction, of zeroth order in 1/Nc, is
entirely fixed by the splitting between the singlet states Lambda(1405) and
Lambda(1520), and the spin-orbit puzzle is solved by the presence of other
zeroth order operators involving flavor exchange.Comment: 31 pages, 3 figure
Precise nuclear matter densities from heavy-ion collisions
An unfolding method is proposed to extract ground-state nuclear matter densities from heavy-ion elastic scattering data analyses at low (sub-barrier) and intermediate energies. The consistency of the results is fully checked. The method should be of value in determining densities for exotic nuclei
Determination of the 12C nuclear density through heavy-ion elastic scattering experiments
Precise elastic scattering differential cross sections have been measured for the 12C158Ni,208Pb systems at
sub-barrier energies. The corresponding bare potentials have been determined at interaction distances larger
than the respective barrier radii, and the results have been compared with those from an early extensive
systematics for the nuclear potential. The present data have been combined with others for the 12C
112C,208Pb systems at intermediate energies, in order to extract the 12C ground-state nuclear density through
an unfolding method
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