Development of Replacement Heifers using Combinations of Three Forage Types and Feed Supplements (with or without Broiler Litter)

The proper management of replacement heifers is an essential component of successful cow/calf operations. The level of management and nutrition applied to replacement heifers as calves and yearlings can impact their subsequent reproductive performance and productivity

On the Sensitivity of 3-D Thermal Convection Codes to Numerical Discretization: A Model Intercomparison

Fully 3-D numerical simulations of thermal convection in a spherical shell have become a standard for studying the dynamics of pattern formation and its stability under perturbations to various parameter values. The question arises as to how does the discretization of the governing equations affect the outcome and thus any physical interpretation. This work demonstrates the impact of numerical discretization on the observed patterns, the value at which symmetry is broken, and how stability and stationary behavior is dependent upon it. Motivated by numerical simulations of convection in the Earth\u27s mantle, we consider isoviscous Rayleigh-Bénard convection at infinite Prandtl number, where the aspect ratio between the inner and outer shell is 0.55. We show that the subtleties involved in development mantle convection models are considerably more delicate than has been previously appreciated, due to the rich dynamical behavior of the system. Two codes with different numerical discretization schemes: an established, community-developed, and benchmarked finite element code (CitcomS) and a novel spectral method that combines Chebyshev polynomials with radial basis functions (RBF) are compared. A full numerical study is investigated for the following three cases. The first case is based on the cubic (or octahedral) initial condition (spherical harmonics of degree ℓ =4). How variations in the behavior of the cubic pattern to perturbations in the initial condition and Rayleigh number between the two numerical discrezations is studied. The second case investigates the stability of the dodecahedral (or icosahedral) initial condition (spherical harmonics of degree ℓ = 6). Although both methods converge first to the same pattern, this structure is ultimately unstable and systematically degenerates to cubic or tetrahedral symmetries, depending on the code used. Lastly, a new steady state pattern is presented as a combination of order 3 and 4 spherical harmonics leading to a five cell or a hexahedral pattern and stable up to 70 times the critical Rayleigh number. This pattern can provide the basis for a new accuracy benchmark for 3-D spherical mantle convection codes

Mechanical properties of magnetostrictive iron-gallium alloys

Single crystal specimens of Fe-17 at. % Ga were tested in tension at room temperature. Specimens with a tensile axis orientation of [110] displayed slip lines on the specimen faces corresponding to slip on the {110}with a critical resolved shear stress of 220 MPa. Yielding began at 0.3% elongation and 450 MPa. An ultimate tensile strength of 580 MPa was observed with no fracture occurring through 1.6% elongation. The Young s modulus was 160 GPa in the loading direction with a Poisson s ratio of -0.37 on the (100) major face. A specimen with a tensile axis orientation of [100] showed slip lines corresponding to slip on the {211}with critical resolved shear stress of 240 MPa. Discontinuous yielding began at 0.8% elongation, which was thought to result from twinning, kink band formation, or stress-induced transformation. The Young\u27s modulus was 65 GPa in the loading direction with a Poisson s ratio of 0.45 on the (001) major face. A maximum tensile strength of 515 MPa was observed with fracture occurring after 2% elongation. A sizeable elastic anisotropy of 19.9 was identified for Fe-27.2 at. % Ga accompanied by a Poisson\u27s ratio of -0.75 to produce a large in-plane auxetic behavior

Stability of the Excitonic Phase in Bilayer Quantum Hall Systems at Total Filling One -- Effects of Finite Well Width and Pseudopotentials --

The ground state of a bilayer quantum Hall system at $\nu_{\rm T}=1$ with model pseudopotential is investigated by the DMRG method. Firstly, pseudopotential parameters appropriate for the system with finite layer thickness are derived, and it is found that the finite thickness makes the excitonic phase more stable. Secondly, a model, where only a few pseudopotentials with small relative angular momentum have finite values, is studied, and it is clarified how the excitonic phase is destroyed as intra-layer pseudopotential becomes larger. The importance of the intra-layer repulsive interaction at distance twice of the magnetic length for the destruction of the excitonic phase is found.Comment: 7 pages, 7 figure

Wess-Zumino sigma models with non-Kahlerian geometry

Supersymmetry of the Wess-Zumino (N=1, D=4) multiplet allows field equations that determine a larger class of geometries than the familiar Kahler manifolds, in which covariantly holomorphic vectors rather than a scalar superpotential determine the forces. Indeed, relaxing the requirement that the field equations be derivable from an action leads to complex flat geometry. The Batalin-Vilkovisky formalism is used to show that if one requires that the field equations be derivable from an action, we once again recover the restriction to Kahler geometry, with forces derived from a scalar superpotential.Comment: 13 pages, Late

Swift Observations of Hard X-ray Emitting White Dwarfs in Symbiotic Stars

The X-ray emission from most accreting white dwarfs (WDs) in symbiotic binary stars is quite soft. Several symbiotic WDs, however, produce strong X-ray emission at energies greater than ~20 keV. The Swift BAT instrument has detected hard X-ray emission from 4 such accreting WDs in symbiotic stars: RT Cru, T CrB, CD -57 3057, and CH Cyg. In one case (RT Cru), Swift detected X-rays out to greater than 50 keV at a > 5 sigma confidence level. Combining data from the XRT and BAT detectors, we find that the 0.3-150 keV spectra of RT Cru, T CrB, and CD -57 3057 are well described by emission from a single-temperature, optically thin thermal plasma, plus an unresolved 6.4-6.9 keV Fe line complex. The X-ray spectrum of CH Cyg contains an additional bright soft component. For all 4 systems, the spectra suffer high levels of absorption from material that both fully and partially covers the source of hard X-rays. The XRT data did not show any of the rapid, periodic variations that one would expect if the X-ray emission were due to accretion onto a rotating, highly magnetized WD. The X-rays were thus more likely from the accretion-disk boundary layer around a massive, non-magnetic WD in each binary. The X-ray emission from RT Cru varied on timescales of a few days. This variability is consistent with being due to changes in the absorber that partially covers the source, suggesting localized absorption from a clumpy medium moving into the line of sight. The X-ray emission from CD -57 3057 and T CrB also varied during the 9 months of Swift observations, in a manner that was also consistent with variable absorption.Comment: Accepted for publication in ApJ. 9 pages, 6 figure

The Properties of Large Amplitude Whistler Mode Waves in the Magnetosphere: Propagation and Relationship with Geomagnetic Activity

Wepresent resultsof a studyof the characteristicsof very large amplitude whistler mode waves inside the terrestrial magnetosphere at radial distances of less than 15 RE using waveform capture data from the Wind spacecraft. We observed 247 whistler mode waves with at least one electric field component (105/247 had !80 mV/m peak!to!peak amplitudes) and 66 whistler mode waves with at least one search coil magnetic field component (38/66 had !0.8 nT peak!to!peak amplitudes). Wave vectors determined from events with three magnetic field components indicate that 30/46 propagate within 20 of the ambient magnetic field, though some are more oblique (up to "50 ). No relationship was observed between wave normal angle and GSM latitude. 162/247 of the large amplitude whistler mode waves were observed during magnetically active periods (AE > 200 nT). 217 out of 247 total whistler mode waves examined were observed inside the radiation belts. We present a waveform capture with the largest whistler wave magnetic field amplitude (^8 nT peak!to!peak) ever reported in the radiation belts. The estimated Poynting flux magnitude associated with this wave is ^300 mW/m2, roughly four orders of magnitude above estimates from previous satellite measurements. Such large Poynting flux values are consistent with rapid energization of electrons