An Evaluation of Variety--Interactions Under Conservation Tillage Wheat Cropping Systems

While many spring and winter wheat (Triticum aestivum) varieties have been evaluated for yield characteristics under Utah\u27s conventional dryland cropping systems, little is known about these same varieties under new conservation tillage farming management techniques. Farmers are rapidly adopting various reduced tillage systems and need information regarding proper varieties, fertility practices, weed control , etc. A two year field study, in Box Elder County, Utah on a DeJarnet Gravelly silt loam (Loamy-skeletal, mixed, mesic, Calcic Pachic Haploxeroll) and on a Mendon silt loam (fine-silty, mixed, mesic, Calcic Pachic Argixeroll) examined total dry matter, grain yield, percent protein, kernel weight, kernel volume, and average bushel weight responses to four fertility treatments superimposed upon five spring wheat and four winter wheat varieties. Also compared were one spring wheat variety Komar and one winter wheat variety Weston in a conventional verses conservation tillage dryl and c ropping system. Soi 1 moisture and soi 1 temperature (20 em and 10 em, respectively bel ow the soi 1 surface) readings were compared between the conventional and conservation tillage planting systems. The conservation tillage plantings were done with an air-seeding tillage planter and the conventional plantings were done with standard deep-furrow drills. Dry granular fertilizer (27 -12-0-4 sulfur) was applied to both deepfurrow and conservation tillage plots with the air-seeder. Rates were 0, 168, 224, 280 kg/ha fertilizer material applied. Significant differences were obtained for all spring wheat varieties. Conservation-tilled Komar yielded significant yield increases over conventional-tilled Komar . The opposite held true for Weston , with the conventional-tilled plots yielding a slightly significant increase in grain over conservation-tillage Weston . No relative difference in soil water or soil temperature were observed in either variety through time. However, at certain growth stages the differences were clearly discernable. Very little significant differences were established among the winter wheat varieties. Because of heavy infestations of snowmold (Calonectria graminicola) on all winter wheat plots, the true potential yield characteristics of conservation verses conventional tillage remain unproven on these winter wheat varieties

The Structure of Global Attractors for Dissipative Zakharov Systems with Forcing on the Torus

The Zakharov system was originally proposed to study the propagation of Langmuir waves in an ionized plasma. In this paper, motivated by earlier work of the first and third authors, we numerically and analytically investigate the dynamics of the dissipative Zakharov system on the torus in 1 dimension. We find an interesting family of stable periodic orbits and fixed points, and explore bifurcations of those points as we take weaker and weaker dissipation.Comment: 16 pages, 7 figure

Introducing Big Sagebrush into a Crested Wheatgrass Monoculture

Crested wheatgrass (Agropyron desertorum or A. cristatum) has been effectively used to stabilize arid and semi-arid range sites for decades. Reestablishing native plant materials into these areas is often desirable to increase wildlife habitat and ecological diversity. Due to its competitive nature, efforts to reestablish native plants into crested wheatgrass monocultures have had limited success. Tillage will control the grass but leaves the soil vulnerable to erosion and weed invasion. This publication will report on a trial conducted near Nephi, Utah to find a method of introducing native plants into a crested wheatgrass monoculture without subjecting the resource base to degradation in the conversion process. In this trial, the effect of chemically controlling crested wheatgrass before transplanting big sagebrush (Artemisia tridentata) was studied. Small container grown plants of sagebrush were transplanted either directly into a 60 year-old stand of crested wheatgrass or after chemically controlling the grass. Three different subspecies of big sagebrush; Basin big sagebrush (Artemisia tridentata Nutt. ssp. tridentata), Mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) and Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young); were planted to see if there would be differences among subspecies. Four years of data indicate that controlling crested wheatgrass prior to transplanting resulted in higher sagebrush survival and faster establishment. There were some differences among sagebrush subspecies. Basin big sagebrush survived equally well with or without grass control but grew faster with grass control. Chemical control of the grass was important for both the survival and growth of Mountain big sage and Wyoming big sage

Conservation laws for systems of extended bodies in the first post-Newtonian approximation.

The general form of the global conservation laws for $N$-body systems in the first post-Newtonian approximation of general relativity is considered. Our approach applies to the motion of an isolated system of $N$ arbitrarily composed and shaped, weakly self-gravitating, rotating, deformable bodies and uses a framework recently introduced by Damour, Soffel and Xu (DSX). We succeed in showing that seven of the first integrals of the system (total mass-energy, total dipole mass moment and total linear momentum) can be broken up into a sum of contributions which can be entirely expressed in terms of the basic quantities entering the DSX framework: namely, the relativistic individual multipole moments of the bodies, the relativistic tidal moments experienced by each body, and the positions and orientations with respect to the global coordinate system of the local reference frames attached to each body. On the other hand, the total angular momentum of the system does not seem to be expressible in such a form due to the unavoidable presence of irreducible nonlinear gravitational effects.Comment: 18 pages, Revte

Equations of motion according to the asymptotic post-Newtonian scheme for general relativity in the harmonic gauge

The asymptotic scheme of post-Newtonian approximation defined for general relativity (GR) in the harmonic gauge by Futamase & Schutz (1983) is based on a family of initial data for the matter fields of a perfect fluid and for the initial metric, defining a family of weakly self-gravitating systems. We show that Weinberg's (1972) expansion of the metric and his general expansion of the energy-momentum tensor ${\bf T}$, as well as his expanded equations for the gravitational field and his general form of the expanded dynamical equations, apply naturally to this family. Then, following the asymptotic scheme, we derive the explicit form of the expansion of ${\bf T}$ for a perfect fluid, and the expanded fluid-dynamical equations. (These differ from those written by Weinberg.) By integrating these equations in the domain occupied by a body, we obtain a general form of the translational equations of motion for a 1PN perfect-fluid system in GR. To put them into a tractable form, we use an asymptotic framework for the separation parameter $\eta$, by defining a family of well-separated 1PN systems. We calculate all terms in the equations of motion up to the order $\eta ^3$ included. To calculate the 1PN correction part, we assume that the Newtonian motion of each body is a rigid one, and that the family is quasi-spherical, in the sense that in all bodies the inertia tensor comes close to being spherical as $\eta \to 0$. Apart from corrections that cancel for exact spherical symmetry, there is in the final equations of motion one additional term, as compared with the Lorentz-Droste (Einstein-Infeld-Hoffmann) acceleration. This term depends on the spin of the body and on its internal structure.Comment: 42 pages, no figure. Version accepted for publication in Physical Review

Development and Pilot Feasibility Study of a Health Information Technology Tool to Calculate Mortality Risk for Patients with Asymptomatic Carotid Stenosis: The Carotid Risk Assessment Tool (CARAT)

Patients with no history of stroke but with stenosis of the carotid arteries can reduce the risk of future stroke with surgery or stenting. At present, a physicians’ ability to recommend optimal treatments based on an individual’s risk profile requires estimating the likelihood that a patient will have a poor peri-operative outcomes and the likelihood that the patient will survive long enough to gain benefit from the procedure. We describe the development of the CArotid Risk Assessment Tool (CARAT) into a 2-year mortality risk calculator within the electronic medical record, integrating the tool into the clinical workflow, training the clinical team to use the tool, and assessing the feasibility and acceptability of the tool in one clinic setting

Three-dimensional sound propagation models using the parabolic-equation approximation and the split-step Fourier method

Author Posting. © IMACS, 2012. This article is posted here by permission of World Scientific Publishing for personal use, not for redistribution. The definitive version was published in Journal of Computational Acoustics 21 (2013): 1250018, doi:10.1142/S0218396X1250018X.The split-step Fourier method is used in three-dimensional parabolic-equation (PE) models to compute underwater sound propagation in one direction (i.e. forward). The method is implemented in both Cartesian (x, y, z) and cylindrical (r, θ, z) coordinate systems, with forward defined as along x and radial coordinate r, respectively. The Cartesian model has uniform resolution throughout the domain, and has errors that increase with azimuthal angle from the x axis. The cylindrical model has consistent validity in each azimuthal direction, but a fixed cylindrical grid of radials cannot produce uniform resolution. Two different methods to achieve more uniform resolution in the cylindrical PE model are presented. One of the methods is to increase the grid points in azimuth, as a function of r, according to nonaliased sampling theory. The other is to make use of a fixed arc-length grid. In addition, a point-source starter is derived for the three-dimensional Cartesian PE model. Results from idealized seamount and slope calculations are shown to compare and verify the performance of the three methods.This work was sponsored by the Office of Naval Research under the grants N00014-10-1-0040 and N00014-11-1-0701

First preliminary tests of the general relativistic gravitomagnetic field of the Sun and new constraints on a Yukawa-like fifth force from planetary data

The general relativistic Lense-Thirring precessions of the perihelia of the inner planets of the Solar System are about 10^-3 arcseconds per century. Recent improvements in planetary orbit determination may yield the first observational evidence of such a tiny effect. Indeed, corrections to the known perihelion rates of -0.0036 +/- 0.0050, -0.0002 +/- 0.0004 and 0.0001 +/- 0.0005 arcseconds per century were recently estimated by E.V. Pitjeva for Mercury, the Earth and Mars, respectively, on the basis of the EPM2004 ephemerides and a set of more than 317,000 observations of various kinds. The predicted relativistic Lense-Thirring precessions for these planets are -0.0020, -0.0001 and -3 10^-5 arcseconds per century, respectively and are compatible with the determined perihelia corrections. The relativistic predictions fit better than the zero-effect hypothesis, especially if a suitable linear combination of the perihelia of Mercury and the Earth, which a priori cancels out any possible bias due to the solar quadrupole mass moment, is considered. However, the experimental errors are still large. Also the latest data for Mercury processed independently by Fienga et al. with the INPOP ephemerides yield preliminary insights about the existence of the solar Lense-Thirring effect. The data from the forthcoming planetary mission BepiColombo will improve our knowledge of the orbital motion of this planet and, consequently, the precision of the measurement of the Lense-Thirring effect. As a by-product of the present analysis, it is also possible to constrain the strength of a Yukawa-like fifth force to a 10^-12-10^-13 level at scales of about one Astronomical Unit (10^11 m).Comment: LaTex, 22 pages, 1 figure, 5 tables, 62 references. To appear in Planetary and Space Scienc

Characterization of impact pile driving signals during installation of offshore wind turbine foundations

Author Posting. © Acoustical Society of America, 2020. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 147(4), (2020): 2323, doi:10.1121/10.0001035.Impact pile driving creates intense, impulsive sound that radiates into the surrounding environment. Piles driven vertically into the seabed generate an azimuthally symmetric underwater sound field whereas piles driven on an angle will generate an azimuthally dependent sound field. Measurements were made during pile driving of raked piles to secure jacket foundation structures to the seabed in waters off the northeastern coast of the U.S. at ranges between 500 m and 15 km. These measurements were analyzed to investigate variations in rise time, decay time, pulse duration, kurtosis, and sound received levels as a function of range and azimuth. Variations in the radiated sound field along opposing azimuths resulted in differences in measured sound exposure levels of up to 10 dB and greater due to the pile rake as the sound propagated in range. The raked pile configuration was modeled using an equivalent axisymmetric FEM model to describe the azimuthally dependent measured sound fields. Comparable sound level differences in the model results confirmed that the azimuthal discrepancy observed in the measured data was due to the inclination of the pile being driven relative to the receiver.This paper was presented at the fifth International Meeting on The Effects of Noise on Aquatic Life held in Den Haag, July 2019. Study concept, oversight, and funding for the experiment were provided by the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM), Environmental Studies Program, Washington, DC, under Contract No. M15PC00002, Task Order M16PD00025. Collaborators in this project include Randy Gallien and Anwar Khan (HDR, Inc.).2020-10-1