Are polar liquids less simple?

Strong correlation between equilibrium fluctuations of the potential energy, U, and the virial, W, is a characteristic of a liquid that implies the presence of certain dynamic properties, such as density scaling of the relaxation times and isochronal superpositioning of the relaxation function. In this work we employ molecular dynamics simulations (mds) on methanol and two variations, lacking hydrogen bonds and a dipole moment, to assess the connection between the correlation of U and W and these dynamic properties. We show, in accord with prior results of others [T.S. Ingebrigtsen, T.B. Schroder, J.C. Dyre, Phys. Rev. X 2, 011011 (2012).], that simple van der Waals liquids exhibit both strong correlations and the expected dynamic behavior. However, for polar liquids this correspondence breaks down - weaker correlation between U and W is not associated with worse conformance to density scaling or isochronal superpositioning. The reason for this is that strong correlation between U and W only requires their proportionality, whereas the expected dynamic behavior depends primarily on constancy of the proportionality constant for all state points. For hydrogen-bonded liquids, neither strong correlation nor adherence to the dynamic properties is observed; however, this nonconformance is not directly related to the concentration of hydrogen bonds, but rather to the greater deviation of the intermolecular potential from an inverse power law (IPL). Only (hypothetical) liquids having interactions governed strictly by an IPL are perfectly correlating and exhibit the consequent dynamic properties over all thermodynamic conditions.Comment: 14 pages, 8 figure

Quark condensate in one-flavor QCD

We compute the condensate in QCD with a single quark flavor using numerical simulations with the overlap formulation of lattice fermions. The condensate is extracted by fitting the distribution of low lying eigenvalues of the Dirac operator in sectors of fixed topological charge to the predictions of Random Matrix Theory. Our results are in excellent agreement with estimates from the orientifold large-N_c expansion.Comment: 12 pages, 4 figures, REVTeX4, v2: Small changes, extended introduction, published versio

Mode-sum regularization of the scalar self-force: Formulation in terms of a tetrad decomposition of the singular field

We examine the motion in Schwarzschild spacetime of a point particle endowed with a scalar charge. The particle produces a retarded scalar field which interacts with the particle and influences its motion via the action of a self-force. We exploit the spherical symmetry of the Schwarzschild spacetime and decompose the scalar field in spherical-harmonic modes. Although each mode is bounded at the position of the particle, a mode-sum evaluation of the self-force requires regularization because the sum does not converge: the retarded field is infinite at the position of the particle. The regularization procedure involves the computation of regularization parameters, which are obtained from a mode decomposition of the Detweiler-Whiting singular field; these are subtracted from the modes of the retarded field, and the result is a mode-sum that converges to the actual self-force. We present such a computation in this paper. There are two main aspects of our work that are new. First, we define the regularization parameters as scalar quantities by referring them to a tetrad decomposition of the singular field. Second, we calculate four sets of regularization parameters (denoted schematically by A, B, C, and D) instead of the usual three (A, B, and C). As proof of principle that our methods are reliable, we calculate the self-force acting on a scalar charge in circular motion around a Schwarzschild black hole, and compare our answers with those recorded in the literature.Comment: 38 pages, 2 figure

Changes in Producers’ Perceptions of Within-field Yield Variability Following Adoption of Cotton Yield Monitors

Precision Farming, Risk, Yield Monitor, Yield Variability, Yield Perceptions, Spatial Yield Distributions, Within Field Variability, Farm Management, Production Economics, Risk and Uncertainty, Q12, Q16,

The Effects of Sarsaponin and Bacitracin MD on Performance of Growing-Finishing Pigs

Feed additives have been used to promote growth and feed efficiency of growing-finishing pigs for over 30 years. Typically, greatest response is found during early stages of growth and less response during the finishing period under conditions of good management. Recently, sarsaponin, a naturally occurring plant steroid derived from the yucca plant, has become available as a feed additive under the commercial name, Micro-Aid. Claims for this product include increased performance of· pigs during the finishing period. The antibiotic, Bacitracin MD, also has been shown to improve performance during later stages of growth more than is expected of most feed additives. The study reported herein was designed to evaluate the response of pigs to these two feed additives when fed separately or in combination

Sunflower Meal in Diets of Growing-finishing Pigs

Sunflower meal, a by-product of the sunflower oil industry, has become increasingly available as a livestock supplement in recent years. Although lower in protein and lysine than soybean meal, an economic advantage for sunflower meal may exist on a cost per unit of lysine or protein basis. Using synthetic lysine and sunflower meal as feed ingredients, diets can be formulated which are equal in protein and lysine to corn-soybean meal diets. The study reported herein was designed to evaluate substituting sunflower meal for soybean meal in growing-finishing pig diets

Pen Space and Antibiotic Effects on Performance of Growing-Finishing Pigs

The detrimental effects of crowding weaned pigs and the advantage of inclusion of an antibiotic in the diets fed from 4 weeks of age to 40 lb has been documented (SWINE 81-8) as a part of a North Central regional project by the Swine Confinement Management Committee. It is of interest to know if the same responses to crowding and presence of antibiotics can be observed with growing-finishing pigs. This study, also part of a regional study, was designed to evaluate the possible effect of antibiotics and pen space on growing-finishing pigs and the interaction of these two factors