518 research outputs found
Effects of Protein Level and Gender on Estimation of Lean Gain per Day of Pigs from a Terminal Crossbreeding System
Lean growth potential is currently used to typify pigs when designing nutritional programs The most common method of estimating lean growth type is by measuring gain over the growth-finsih period and obtaining carcass information for the pigs evaluated. This information is placed in a model to calculate lean gain/day. Excess protein is fed to ensure that the genetic potential for lean gain per day is not limited by nutrition. The data reported herein are the results of determining the lean growth potential of the SDSU research herd in 1992 with pigs fed two different protein regimens
Effects of Dietary Energy Concentration During the Grower Period on the Accuracy of Determining Lean Gain Potential During the Finisher Period for Pigs Selected During the Grower Period by Either a Lean Gain Formula or by Plasma Urea Nitrogen Concentration as an Indicator of Lean Gain
It is generally thought that pigs eat to satisfy their demand for energy and the amount of feed consumed is dependent on the energy density of the diet. Therefore, the amount of feed consumed when an energy-dense diet is fed will be lower than when a low energy diet is fed. Protein is the nutrient that is most frequently adjusted as energy density in the diet is changed. Energy intake influences the rates of deposition of lean and fat tissue. Nitrogen accretion is generally limited by voluntary intake of energy for pigs weighing less than 50 kg but not for pigs weighing over 50 kg body weight. When the rate of protein deposition reaches a plateau for a given gender and genotype of pig, further increases in energy intake result in an increased deposition of fat tissue. It is thought that lean gain/day is negatively correlated with plasma urea nitrogen (PUN) concentrations. In a diet with proper balance of amino acids, PUN levels will increase as the protein concentration of the diet exceeds the protein requirement of the pigs. Pigs with higher lean growth requir4e a higher concentration of amino acids When a group of pigs are fed a given protein concentration, pigs with a higher lean gain/day are expected to have lower PUN concentrations. To maximize efficient production, there would be merit to sorting pigs by their lean gain potential enabling the producer to better match the nutritional needs of each genotype with the pig’s ability to partition energy toward lean and away from fat deposition. The objective of this study was to evaluate the effect of energy concentration of the grower diet on the ability to sort pigs from a contemporary farrowing group based on high or low lean growth potential estimated by (a) lean gain/day (LGPD) based on the NPPC (1991) formula using gain and ultrasound measurements during the grower period of (b) PUN concentrations at the end of the grower period
Extended M1 sum rule for excited symmetric and mixed-symmetry states in nuclei
A generalized M1 sum rule for orbital magnetic dipole strength from excited
symmetric states to mixed-symmetry states is considered within the
proton-neutron interacting boson model of even-even nuclei. Analytic
expressions for the dominant terms in the B(M1) transition rates from the first
and second states are derived in the U(5) and SO(6) dynamic symmetry
limits of the model, and the applicability of a sum rule approach is examined
at and in-between these limits. Lastly, the sum rule is applied to the new data
on mixed-symmetry states of 94Mo and a quadrupole d-boson ratio
is obtained in a largely
parameter-independent wayComment: 19 pages, 3 figures, Revte
Red Queen Coevolution on Fitness Landscapes
Species do not merely evolve, they also coevolve with other organisms.
Coevolution is a major force driving interacting species to continuously evolve
ex- ploring their fitness landscapes. Coevolution involves the coupling of
species fit- ness landscapes, linking species genetic changes with their
inter-specific ecological interactions. Here we first introduce the Red Queen
hypothesis of evolution com- menting on some theoretical aspects and empirical
evidences. As an introduction to the fitness landscape concept, we review key
issues on evolution on simple and rugged fitness landscapes. Then we present
key modeling examples of coevolution on different fitness landscapes at
different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and
Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.).
Springer Series in Emergence, Complexity, and Computation, 201
Scaling in Numerical Simulations of Domain Walls
We study the evolution of domain wall networks appearing after phase
transitions in the early Universe. They exhibit interesting dynamical scaling
behaviour which is not yet well understood, and are also simple models for the
more phenomenologically acceptable string networks. We have run numerical
simulations in two- and three-dimensional lattices of sizes up to 4096^3. The
theoretically predicted scaling solution for the wall area density A ~ 1/t is
supported by the simulation results, while no evidence of a logarithmic
correction reported in previous studies could be found. The energy loss
mechanism appears to be direct radiation, rather than the formation and
collapse of closed loops or spheres. We discuss the implications for the
evolution of string networks.Comment: 7pp RevTeX, 9 eps files (including six 220kB ones
Cosmological parameters from SDSS and WMAP
We measure cosmological parameters using the three-dimensional power spectrum
P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in
combination with WMAP and other data. Our results are consistent with a
``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt,
tensor modes or massive neutrinos. Adding SDSS information more than halves the
WMAP-only error bars on some parameters, tightening 1 sigma constraints on the
Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter
density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on
neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when
dropping prior assumptions about curvature, neutrinos, tensor modes and the
equation of state. Our results are in substantial agreement with the joint
analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive
consistency check with independent redshift survey data and analysis
techniques. In this paper, we place particular emphasis on clarifying the
physical origin of the constraints, i.e., what we do and do not know when using
different data sets and prior assumptions. For instance, dropping the
assumption that space is perfectly flat, the WMAP-only constraint on the
measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to
t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running
tilt, neutrino mass and equation of state in the list of free parameters, many
constraints are still quite weak, but future cosmological measurements from
SDSS and other sources should allow these to be substantially tightened.Comment: Minor revisions to match accepted PRD version. SDSS data and ppt
figures available at http://www.hep.upenn.edu/~max/sdsspars.htm
Statistics of Cosmological Inhomogeneities
This contribution to the Proceedings is based on the talk given at the
Conference on Birth of the Universe and Fundamental Physics, Rome, May 18-21,
1994. Some selected topics of the subject are reviewed: Models of Primordial
Fluctuations; Reconstruction of the Cosmological Density Probability
Distribution Function (PDF) from Cumulants; PDFs from the Zel'dovich
Approximation and from Summarizing Perturbation Series; Fitting by the
Log-normal Distribution.Comment: 11 pages, 3 figures (available from the author), LaTe
Origin and Evolution of Saturn's Ring System
The origin and long-term evolution of Saturn's rings is still an unsolved
problem in modern planetary science. In this chapter we review the current
state of our knowledge on this long-standing question for the main rings (A,
Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During
the Voyager era, models of evolutionary processes affecting the rings on long
time scales (erosion, viscous spreading, accretion, ballistic transport, etc.)
had suggested that Saturn's rings are not older than 100 My. In addition,
Saturn's large system of diffuse rings has been thought to be the result of
material loss from one or more of Saturn's satellites. In the Cassini era, high
spatial and spectral resolution data have allowed progress to be made on some
of these questions. Discoveries such as the ''propellers'' in the A ring, the
shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus' plume
provide new constraints on evolutionary processes in Saturn's rings. At the
same time, advances in numerical simulations over the last 20 years have opened
the way to realistic models of the rings's fine scale structure, and progress
in our understanding of the formation of the Solar System provides a
better-defined historical context in which to understand ring formation. All
these elements have important implications for the origin and long-term
evolution of Saturn's rings. They strengthen the idea that Saturn's rings are
very dynamical and rapidly evolving, while new arguments suggest that the rings
could be older than previously believed, provided that they are regularly
renewed. Key evolutionary processes, timescales and possible scenarios for the
rings's origin are reviewed in the light of tComment: Chapter 17 of the book ''Saturn After Cassini-Huygens'' Saturn from
Cassini-Huygens, Dougherty, M.K.; Esposito, L.W.; Krimigis, S.M. (Ed.) (2009)
537-57
Evidence for an Excess of Soft Photons in Hadronic Decays of Z^0
Soft photons inside hadronic jets converted in front of the DELPHI main
tracker (TPC) in events of qqbar disintegrations of the Z^0 were studied in the
kinematic range 0.2 < E_gamma < 1 GeV and transverse momentum with respect to
the closest jet direction p_T < 80 MeV/c. A clear excess of photons in the
experimental data as compared to the Monte Carlo predictions is observed. This
excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/-
0.27) x 10^{-3} gamma/jet in the specified kinematic region, while the expected
level of the inner hadronic bremsstrahlung (which is not included in the Monte
Carlo) is (0.340 +/- 0.001 +/- 0.038) x 10^{-3} gamma/jet. The ratio of the
excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8),
which is similar in strength to the anomalous soft photon signal observed in
fixed target experiments with hadronic beams.Comment: 37 pages, 9 figures, Accepted by Eur. Phys. J.
Study of Inclusive J/psi Production in Two-Photon Collisions at LEP II with the DELPHI Detector
Inclusive J/psi production in photon-photon collisions has been observed at
LEP II beam energies. A clear signal from the reaction gamma gamma -> J/psi+X
is seen. The number of observed N(J/psi -> mu+mu-) events is 36 +/- 7 for an
integrated luminosity of 617 pb^{-1}, yielding a cross-section of
sigma(J/psi+X) = 45 +/- 9 (stat) +/- 17 (syst) pb. Based on a study of the
event shapes of different types of gamma gamma processes in the PYTHIA program,
we conclude that (74 +/- 22)% of the observed J/psi events are due to
`resolved' photons, the dominant contribution of which is most probably due to
the gluon content of the photon.Comment: 13 pages, 8 figures, Accepted by Phys. Lett.
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