5,454 research outputs found
Inclusive neutrino scattering off deuteron from threshold to GeV energies
Background: Neutrino-nucleus quasi-elastic scattering is crucial to interpret
the neutrino oscillation results in long baseline neutrino experiments. There
are rather large uncertainties in the cross section, due to insufficient
knowledge on the role of two-body weak currents. Purpose: Determine the role of
two-body weak currents in neutrino-deuteron quasi-elastic scattering up to GeV
energies. Methods: Calculate cross sections for inclusive neutrino scattering
off deuteron induced by neutral and charge-changing weak currents, from
threshold up to GeV energies, using the Argonne potential and
consistent nuclear electroweak currents with one- and two-body terms. Results:
Two-body contributions are found to be small, and increase the cross sections
obtained with one-body currents by less than 10% over the whole range of
energies. Total cross sections obtained by describing the final two-nucleon
states with plane waves differ negligibly, for neutrino energies
MeV, from those in which interaction effects in these states are fully
accounted for. The sensitivity of the calculated cross sections to different
models for the two-nucleon potential and/or two-body terms in the weak current
is found to be weak. Comparing cross sections to those obtained in a naive
model in which the deuteron is taken to consist of a free proton and neutron at
rest, nuclear structure effects are illustrated to be non-negligible.
Conclusion: Contributions of two-body currents in neutrino-deuteron
quasi-elastic scattering up to GeV are found to be smaller than 10%. Finally,
it should be stressed that the results reported in this work do not include
pion production channels.Comment: 30 pages, 17 figures; publishe
Swine antibiotics and feed additives : food safety considerations
AGRICULTURALMU GuidePUBLISHED BY MU EXTENSION, UNIVERSITY OF MISSOURI-COLUMBIASwine feeding"In many instances, antibiotics are used to promote growth, or weight. It is generally accepted that antibiotics aid in the promotion of quality pork growth through a direct metabolic effect, by sparing use of nutrients or by controlling low levels of endemic pathogens." -- page 2Marcia S. Carlson and Thomas J. Fangman (Department of Animal Sciences)Reviewed November 2018 -- websit
Direct and indirect lactate oxidation in trained and untrained men.
Lactate has been shown to be an important oxidative fuel. We aimed to quantify the total lactate oxidation rate (Rox) and its direct vs. indirect (glucose that is gluconeogenically derived from lactate and subsequently oxidized) components (mg·kg(-1)·min(-1)) during rest and exercise in humans. We also investigated the effects of endurance training, exercise intensity, and blood lactate concentration ([lactate]b) on direct and indirect lactate oxidation. Six untrained (UT) and six trained (T) men completed 60 min of constant load exercise at power outputs corresponding to their lactate threshold (LT). T subjects completed two additional 60-min sessions of constant load exercise at 10% below the LT workload (LT-10%), one of which included a lactate clamp (LC; LT-10%+LC). Rox was higher at LT in T [22.7 ± 2.9, 75% peak oxygen consumption (Vo2peak)] compared with UT (13.4 ± 2.5, 68% Vo2peak, P < 0.05). Increasing [lactate]b (LT-10%+LC, 67% Vo2peak) significantly increased lactate Rox (27.9 ± 3.0) compared with its corresponding LT-10% control (15.9 ± 2.2, P < 0.05). Direct and indirect Rox increased significantly from rest to exercise, and their relative partitioning remained constant in all trials but differed between T and UT: direct oxidation comprised 75% of total lactate oxidation in UT and 90% in T, suggesting the presence of training-induced adaptations. Partitioning of total carbohydrate (CHO) use showed that subjects derived one-third of CHO energy from blood lactate, and exogenous lactate infusion increased lactate oxidation significantly, causing a glycogen-sparing effect in exercising muscle
Biosecurity for today's swine operation
Original authors: Johnna S. Seaman and Thomas J. Fangman, Department of Veterinary Medicinestats202303upload"Disease control is one of the most challenging areas for producers and veterinarians in swine production. Biosecurity is often perceived as keeping diseases out of a swine herd. However, excluding disease from a herd is nearly impossible because of the natural presence of pathogens — the endemic pathogen load — in all swine herds. Therefore, the goal of a biosecurity program is to keep out pathogens that the herd has not been exposed to and to minimize the impact of endemic pathogens. With a good biosecurity program, optimal growth can be reached by minimizing the negative effects of subclinical illnesses. High reproductive performance can be achieved with a decrease of costly factors such as embryonic loss or preweaning mortality due to disease. This publication introduces key elements of an effective biosecurity program. A final plan can be developed in cooperation with your herd veterinarian to best accommodate constraints for a given operation."--First page.Reviewed by Marcia Carlson Shannon (Department of Animal Sciences). Original authors: Johnna S. Seaman and Thomas J. Fangman (Department of Veterinary Medicine
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The Characterization of Underwater Infrasound Generated by Vibratory Pile Driving Within the Context of the Characteristics of Sound Known to Result in Avoidance Response by Juvenile Salmonids
Little data exists to document the nature of sound generated by vibratory pile driving and the response salmon to that sound. The construction of a new pier at Oregon State University's Hatfield Marine Science Center in 1996 offered the opportunity to monitor the sound. The findings were then related to known results of studies on salmonid response to sound. The author concludes that avoidance behavior is unlikely
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
Catastro de poblaciones de insectos en siembras de Capsicum chinense L. en Georgetown, San Vicente, usando trampas CC modificadas.
The insect populations in hot pepper, Capsicum chinense L. (Solanaceae), were surveyed in Georgetown, St. Vincent, during the 2004 wet and 2005 dry seasons. Modified white, blue, and yellow CC traps were used to capture insects in the plantings. Overall, 69 insect families were captured, 41 of which were captured during both the wet and dry seasons. During the wet season, the greatest numbers of individuals captured were from the Cecidomyiidae, Chironomidae, Chloropidae, Chrysomelidae, Cicadellidae, and Drosophilidae families. During the dry season, the greatest numbers of individuals captured were from Chrysomelidae and Cicadellidae families. The addition of dichlorvos as a killing agent and propylene glycol as an insect preservative to the CC traps increased the number and diversity of insects caught. Additionally, propylene glycol helped to preserve the specimens for taxonomic and genetic determinations. CC traps with yellow bases attracted more insect families than traps with white or blue bases. However, CC traps with blue bases caught more Lonchaeidae during both the wet and dry seasons, and more Tachinidae during the dry season. CC traps with white or yellow trap bases were equally attractive to insects in the families Aleyrodidae, Drosophilidae, Lauxaniidae, and Otitidae.Las poblaciones de insectos en el ajĂ picante, Capsicum chinense L., se monitorearon en Georgetown, San Vicente, durante la Ă©poca de lluvia de 2004 y la de sequĂa de 2005. Se usaron las trampas CC modificadas, blancas, azules y amarillas, para capturar insectos en las siembras. Se capturaron 69 familias de insectos; 41 de Ă©stas se capturaron durante ambas Ă©pocas, la de lluvia y la de sequĂa. Durante la Ă©poca de lluvia, el mayor nĂşmero de individuos capturados pertenecĂa a las familias Cecidomyiidae, Chironomidae, Chloropidae, Chrysomelidae, Cicadellidae y Drosophilidae. Durante la Ă©poca de sequĂa, el mayor nĂşmero de individuos capturados pertenecĂa a las familias Cicadellidae y Chrysomelidae. El nĂşmero y la diversidad de los insectos capturados aumentaron al añadir dichlorvos como un agente exterminador y glicol de propileno como agente preservativo a las trampas CC. Además, el glicol de propileno ayudĂł a preservar los especĂmenes para las determinaciones taxonĂłmicas y genĂ©ticas. Las trampas CC con bases amarillas atrajeron más familias de insectos que las trampas con bases blancas o azules. Sin embargo, las trampas CC con bases azules capturaron más Lonchaeidae durante ambas Ă©pocas, de lluvia y sequĂa, y más Tachinidae durante la Ă©poca de sequĂa. Las trampas CC con bases blancas o amarillas resultaron igualmente atractivas a los insectos en las familias Aleyrodidae, Drosophilidae, Lauxaniidae y Otitidae
A moving grid finite element method applied to a model biological pattern generator
Many problems in biology involve growth. In numerical simulations it can therefore be very convenient to employ a moving computational grid on a continuously deforming domain. In this paper we present a novel application of the moving grid finite element method to compute solutions of reaction–diffusion systems in two-dimensional continuously deforming Euclidean domains. A numerical software package has been developed as a result of this research that is capable of solving generalised Turing models for morphogenesis
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
Characterization of Fish Passage Conditions through a Francis Turbine, Spillway, and Regulating Outlet at Detroit Dam, Oregon, Using Sensor Fish, 2009
Fish passage conditions through two spillways, a Francis turbine, and a regulating outlet (RO) at Detroit Dam on the North Santiam River in Oregon were evaluated by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE), Portland District, using Sensor Fish devices. The objective of the study was to describe and compare passage exposure conditions, identifying potential fish injury regions within the routes. The study was performed in July, October, and December 2009 concurrent with HI-Z balloon-tag studies by Normandeau Associates, Inc. Sensor Fish data were analyzed to estimate 1) exposure conditions, particularly exposure to severe strike, collision, and shear events by passage route sub-regions; 2) differences in passage conditions between passage routes; and 3) relationships to live-fish injury and mortality data estimates. Comparison of the three passage routes evaluated at Detroit Dam indicates that the RO passage route through the 5-ft gate opening was relatively the safest route for fish passage under the operating conditions tested; turbine passage was the most deleterious. These observations were supported also by the survival and malady estimates obtained from live-fish testing. Injury rates were highest for turbine and spillway passage. However, none of the passage routes tested is safe for juvenile salmonid passage
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