South Dakota Retained Ownership Demonstration

Three hundred forty-five steer calves representing 53 cow-calf producers were consigned to a custom feedlot in late October. Cattle were fed in one of two pens. One pen of calves received a moderate roughage growing diet for 39 days and then were switched to a high energy finishing diet (ACC). The other pen of calves received a moderate roughage growing diet for 109 days and then were switched to a high energy finishing diet (TWO). The ACC calves weighed 574 lb initially, gained 2.94 Ib per head daily and were slaughtered at 1147 Ib after an average of 196 days on feed. Average cost of gain and profitability were $52.31 per cwt and$38.75 per head, respectively. The TWO calves weighed 504 Ib initially, gained 2.77 Ib per head daily and were slaughtered at 1096 Ib after an average of 214 days on feed. Average cost of gain and profitability were $52.72 per cwt and$16.69 per head, respectively. Cattle slaughtered later in the spring were less profitable than cattle slaughtered earlier in the spring due to a weaker cattle market and wider choice-select price spread. Across either feeding program, average profits for cattle slaughtered after 170, 192, 199, 200 and 242 days on feed were $50.03,$64.42, $28.69,$27.39 and -$16.78 per head, respectively

Charge injection instability in perfect insulators

We show that in a macroscopic perfect insulator, charge injection at a field-enhancing defect is associated with an instability of the insulating state or with bistability of the insulating and the charged state. The effect of a nonlinear carrier mobility is emphasized. The formation of the charged state is governed by two different processes with clearly separated time scales. First, due to a fast growth of a charge-injection mode, a localized charge cloud forms near the injecting defect (or contact). Charge injection stops when the field enhancement is screened below criticality. Secondly, the charge slowly redistributes in the bulk. The linear instability mechanism and the final charged steady state are discussed for a simple model and for cylindrical and spherical geometries. The theory explains an experimentally observed increase of the critical electric field with decreasing size of the injecting contact. Numerical results are presented for dc and ac biased insulators.Comment: Revtex, 7pages, 4 ps figure

Factors Affecting Weaning Weight Production

Weaning weight records from a commercial cow herd were statistically analyzed to demonstrate suspected sources of variation in weaning weight. Data from first-calf heifers and mature cows (3 to 9 year olds) were analyzed separately. For every one day increase in calf age at weaning, weaning weight was increased by 1.65 and 1.76 Ib for first-calf heifers and mature cows, respectively. For every 1 percentage point increase in MPPA of the cow, weaning weight was increased by 4.5 Ib. A 10% advantage in weaning weights and weight per day of age (WDA) was observed in steers over heifers. A 3 and 6% advantage in WDA and weaning weight, respectively, was observed in bulls over steers. Weaning weight and WDA peaked among cows 4 to 6 years of age and then declined. Cows that were 3, 8 and 9 years of age produced calves with similar weaning weights. Calves nursing 3-, 7- and 8-year-old cows required more treatments for sickness than calves nursing 4- to 6-year-old cows. Production records provide valuable insight into causes of variation in cow productivity

Progress in Lunar Laser Ranging Tests of Relativistic Gravity

Analyses of laser ranges to the Moon provide increasingly stringent limits on any violation of the Equivalence Principle (EP); they also enable several very accurate tests of relativistic gravity. We report the results of our recent analysis of Lunar Laser Ranging (LLR) data giving an EP test of \Delta (M_G/M_I)_{EP} =(-1.0 +/- 1.4) x 10^{-13}. This result yields a Strong Equivalence Principle (SEP) test of \Delta (M_G/M_I)_{SEP} =(-2.0 +/- 2.0) x 10^{-13}. Also, the corresponding SEP violation parameter \eta is (4.4 +/- 4.5) x 10^{-4}, where \eta=4\beta-\gamma-3 and both \beta and \gamma are parametrized post-Newtonian (PPN) parameters. Using the recent Cassini result for the parameter \gamma, PPN parameter \beta is determined to be \beta-1=(1.2 +/- 1.1) x 10^{-4}. The geodetic precession test, expressed as a relative deviation from general relativity, is K_{gp}=-0.0019 +/- 0.0064. The search for a time variation in the gravitational constant results in \dot G/G=(4 +/- 9) x 10^{-13} yr^{-1}, consequently there is no evidence for local (~1AU) scale expansion of the solar system.Comment: 4 pages, revtex4, minor changes made for publicatio

South Dakota Retained Ownership Demonstration

Four hundred nineteen steer calves representing 57 cow-calf producers were consigned to a custom feedlot in mid-October. Cattle were fed in one of three pens. One pen of calves was fed a starter program for 20 days followed by a moderate roughage growing diet for 84 days before they were switched to a high energy finishing diet (TWO). The other two pens were fed a starter program for 20 days followed by a moderate roughage growing diet for 14 days before they were switched to a high energy finishing diet. Cattle were sorted into one of these two pens on the basis of whether they had been exposed to feed (AFED, either weaned or creep fed) prior to feedlot arrival or not exposed to feed (ANFED). The TWO calves weighed 500 1b initially, gained 2.80 Ib per head daily, and averaged 1047 1b at slaughter after an average of 196 days on feed. Average cost of gain and profitability were $58.27 per cwt and$28.74 per head, respectively. The AFED and ANFED calves weighed 539 and 554 Ib initially, gained 3.04 and 3.08 Ib per head daily, and averaged 11 16 and 1136 1b at slaughter after an average of 190 and 189 days on feed, respectively. Average cost of gain and profitability were $55.40 and$56.32 per cwt and $23.57 and$33.20 per head, respectively. When data from years 1 and 2 were combined, average daily gain, dressing percentage, quality grade, and cost of gain were related to profitability and accounted for 79.6% of the variation in profitability

Unified 1-D Simulations of Gamma-Ray Line Emission from Type Ia Supernovae

The light curves of Type Ia Supernovae (SN Ia) are powered by gamma-rays emitted by the decay of radioactive elements such as $^{56}$Ni and its decay products. These gamma-rays are downscattered,absorbed, and eventually reprocessed into the optical emission which makes up the bulk of all supernova observations. Detection of the gamma-rays that escape the expanding star provide the only direct means to study this power source for SN Ia light curves. Unfortunately, disagreements between calculations for the gamma-ray lines have made it difficult to interpret any gamma-ray observations. Here we present a detailed comparison of the major gamma-ray line transport codes for a series of 1-dimensional Ia models. Discrepancies in past results were due to errors in the codes, and the corrected versions of the seven different codes yield very similar results. This convergence of the simulation results allows us to infer more reliable information from the current set of gamma-ray observations of SNe Ia. The observations of SNe 1986G, 1991T and 1998bu are consistent with explosion models based on their classification: sub-luminous, super-luminous and normally-luminous respectively.Comment: Accepted to the Astrophysical Journa

The Anisotropic Distribution of M 31 Satellite Galaxies: A Polar Great Plane of Early-Type Companions

The highly anisotropic distribution and apparent alignment of the Galactic satellites in polar great planes begs the question how common such distributions are. The satellite system of M31 is the only nearby system for which we currently have sufficiently accurate distances to study the three-dimensional satellite distribution. We present the spatial distribution of the 15 presently known M31 companions in a coordinate system centered on M31 and aligned with its disk. Through a detailed statistical analysis we show that the full satellite sample describes a plane that is inclined by -56 deg with respect to the poles of M31 and that has an r.m.s. height of 100 kpc. With 88% the statistical significance of this plane is low and it is unlikely to have a physical meaning. The great stellar stream found near Andromeda is inclined to this plane by 7 deg. There is little evidence for a Holmberg effect. If we confine our analysis to early-type dwarfs, we find a best-fit polar plane within 5 deg to 7 deg from the pole of M31. This polar great plane has a statistical significance of 99.3% and includes all dSphs (except for And II), M32, NGC 147, and PegDIG. The r.m.s. distance of these galaxies from the polar plane is 16 kpc. The nearby spiral M33 has a distance of only about 3 kpc from this plane, which points toward the M81 group. We discuss the anisotropic distribution of M31's early-type companions in the framework of three scenarios, namely as remnants of the break-up of a larger progenitor, as tracer of a prolate dark matter halo, and as tracer of collapse along large-scale filaments. (Abridged)Comment: 14 pages, 5 figures, accepted for publication in the Astronomical Journa

GRBs Neutrinos as a Tool to Explore Quantum Gravity induced Lorentz Violation

Lorentz Invariance Violation (LIV) arises in various quantum-gravity theories. As the typical energy for quantum gravity is the Planck mass, $M_{pl}$, LIV will, most likely, be manifested at very high energies that are not accessible on Earth in the foreseeable future. One has to turn to astronomical observations. Time of flight measurement from different astronomical sources set current limits on the energy scale of possible LIV to $> 0.01 M_{pl}$ (for n=1 models) and $> 10^{-9} M_{pl}$ (for n=2). According to current models Gamma-Ray Bursts (GRBs) are accompanied by bursts of high energy (\gsim 100TeV) neutrinos. At this energy range the background level of currently constructed neutrino detectors is so low that a detection of a single neutrino from the direction of a GRB months or even years after the burst would imply an association of the neutrino with the burst and will establish a measurement of a time of flight delay. Such time of flight measurements provide the best way to observe (or set limits) on LIV. Detection of a single GRB neutrino would open a new window on LIV and would improve current limits by many orders of magnitude

Positron Annihilation in the Galaxy

The 511 keV line from positron annihilation in the Galaxy was the first γ-ray line detected to originate from outside our solar system. Going into the fifth decade since the discovery, the source of positrons is still unconfirmed and remains one of the enduring mysteries in γ-ray astronomy. With a large flux of ∼10−3 γ/cm2/s, after 15 years in operation INTEGRAL/SPI has detected the 511 keV line at >50σ and has performed high-resolution spectral studies which conclude that Galactic positrons predominantly annihilate at low energies in warm phases of the interstellar medium. The results from imaging are less certain, but show a spatial distribution with a strong concentration in the center of the Galaxy. The observed emission from the Galactic disk has low surface brightness and the scale height is poorly constrained, therefore, the shear number of annihilating positrons in our Galaxy is still not well know. Positrons produced in β+-decay of nucleosynthesis products, such as 26Al, can account for some of the annihilation emission in the disk, but the observed spatial distribution, in particular the excess in the Galactic bulge, remains difficult to explain. Additionally, one of the largest uncertainties in these studies is the unknown distance that positrons propagate before annihilation. In this paper, we will summarize the current knowledge base of Galactic positrons, and discuss how next-generation instruments could finally provide the answers.Non peer reviewedFinal Accepted Versio

NuSTAR and Suzaku X-ray Spectroscopy of NGC 4151: Evidence for Reflection from the Inner Accretion Disk

We present X-ray timing and spectral analyses of simultaneous 150 ks Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku X-ray observations of the Seyfert 1.5 galaxy NGC 4151. We disentangle the continuum emission, absorption, and reflection properties of the active galactic nucleus (AGN) by applying inner accretion disk reflection and absorption-dominated models. With a time-averaged spectral analysis, we find strong evidence for relativistic reflection from the inner accretion disk. We find that relativistic emission arises from a highly ionized inner accretion disk with a steep emissivity profile, which suggests an intense, compact illuminating source. We find a preliminary, near-maximal black hole spin a>0.9 accounting for statistical and systematic modeling errors. We find a relatively moderate reflection fraction with respect to predictions for the lamp post geometry, in which the illuminating corona is modeled as a point source. Through a time-resolved spectral analysis, we find that modest coronal and inner disk reflection flux variation drives the spectral variability during the observations. We discuss various physical scenarios for the inner disk reflection model, and we find that a compact corona is consistent with the observed features.Comment: 20 pages, 12 figures, accepted for publication in Ap