8,193 research outputs found
Seedhead Suppression in Tall Fescue with Chaparral Herbicide
Tall Fescue (Lolium arundinaceum (Schreb.)) is cool-season perennial grass found in pastures throughout the Eastern US, most commonly in the transition zone. Itâs tolerance to extreme temperatures, drought, poor soil fertility, heavy grazing, and pests have made it a reliable forage base for livestock pastures. Released in 1943, âKY-31â tall fescue was quickly adopted by cattle producers and now inhabits an estimated 40 million acres in the US.
Soon after its adoption, cattle producers began to notice a reduction in animal performance and signs that animals were heat stressed following tall fescue consumption. These symptoms were an indication of an animal disorder that would later be called âfescue toxicosisâ by scientists and producers. In the late 1970s, it was discovered that the cattle health issues with tall fescue were actually caused by a fungus (Neotyphodium coenophialum) living within some plants, which produced a toxic class of compounds termed ergot alkaloids. We refer to these tall fescue plants that contain this fungus as being endophyte infected (E+) and those that do not as being endophyte free (E-)
Partnership for a New Generation of Vehicles: Challenges and Opportunities
https://deepblue.lib.umich.edu/bitstream/2027.42/154100/1/cole-partnership1994.pd
Forage Response and Economic Benefits to Weed Management in Grasslands
A common question among managers of grazing operations is âAt what level of weed pressure does it become economical to apply herbicides on pastures?â Unfortunately, there isnât just one answer to this question as production goals and practices differ between operations and even within an operation over time. Regardless, the real question being ask is if weed control will increase profit per acre.
There are three basic avenues that may be taken to improve profit per acre through weed control. The first is to increase the carrying capacity of the grazing operation by controlling weeds and replacing them with desirable forage species that will support the required increase in animal units. The second is to use weed control to improve forage availability to the existing herd to support higher average daily gains (ADG) or improve body condition (BCS) of animals. The third is to simply improve animal health through control of toxic plants that may suppress animal performance or increase mortality. Here we will only focus on weed control for increased carrying capacity and improved animal performance
A dynamical and kinematical model of the Galactic stellar halo and possible implications for galaxy formation scenarios
We re-analyse the kinematics of the system of blue horizontal branch field
(BHBF) stars in the Galactic halo (in particular the outer halo), fitting the
kinematics with the model of radial and tangential velocity dispersions in the
halo as a function of galactocentric distance r proposed by Sommer-Larsen,
Flynn & Christensen (1994), using a much larger sample (almost 700) of BHBF
stars. The basic result is that the character of the stellar halo velocity
ellipsoid changes markedly from radial anisotropy at the sun to tangential
anisotropy in the outer parts of the Galactic halo (r greater than approx 20
kpc). Specifically, the radial component of the stellar halo's velocity
ellipsoid decreases fairly rapidly beyond the solar circle, from approx 140 +/-
10 km/s at the sun, to an asymptotic value of 89 +/- 19 km/s at large r. The
rapid decrease in the radial velocity dispersion is matched by an increase in
the tangential velocity dispersion, with increasing r.
Our results may indicate that the Galaxy formed hierarchically (partly or
fully) through merging of smaller subsystems - the 'bottom-up' galaxy formation
scenario, which for quite a while has been favoured by most theorists and
recently also has been given some observational credibility by HST observations
of a potential group of small galaxies, at high redshift, possibly in the
process of merging to a larger galaxy (Pascarelle et al 1996).Comment: Latex, 16 pages. 2 postscript figures. Submitted to the Astrophysical
Journal. also available at http://astro.utu.fi/~cflynn/outerhalo.htm
Understanding Individual Tax Compliance: Advanced Deductions And Related Issues
We present a realistic, complex, flexible, classroom-friendly tax case study that is designed to be a late semester comprehensive assignment in a studentâs federal income tax education. The assignment could be used as a template when teaching students how to prepare a federal individual income tax return using the actual forms and schedules prepared by the Internal Revenue Service (IRS). This case is relevant for two reasons: 1) it is contemporary in that it consists of the most recent tax year (2013), and 2) it is highly useful as it comprehensively examines concepts typically covered in the later chapters of a tax text â most itemized deductions, purchase and sale of a residence, casualty and theft loss, moving expenses, employee business expenses, education tax credits, and investment property â while only reviewing information found in earlier chapters. In addition, the case is flexible so that it can be used in future years with only slight modifications for tax law changes
Competition in the 1990s
https://deepblue.lib.umich.edu/bitstream/2027.42/154101/1/cole-competition1994.pd
Relativistic spin precession in the binary PSR J11416545
PSR J11416545 is a precessing binary pulsar that has the rare potential to
reveal the two-dimensional structure of a non-recycled pulsar emission cone. It
has undergone of relativistic spin precession in the
years since its discovery. In this paper, we present a detailed Bayesian
analysis of the precessional evolution of the width of the total intensity
profile, to understand the changes to the line-of-sight impact angle ()
of the pulsar using four different physically motivated prior distribution
models. Although we cannot statistically differentiate between the models with
confidence, the temporal evolution of the linear and circular polarisations
strongly argue that our line-of-sight crossed the magnetic pole around MJD
54000 and that only two models remain viable. For both these models, it appears
likely that the pulsar will precess out of our line-of-sight in the next
years, assuming a simple beam geometry. Marginalising over suggests
that the pulsar is a near-orthogonal rotator and provides the first
polarization-independent estimate of the scale factor () that
relates the pulsar beam opening angle () to its rotational period ()
as : we find it to be at 1.4
GHz with 99\% confidence. If all pulsars emit from opposite poles of a dipolar
magnetic field with comparable brightness, we might expect to see evidence of
an interpulse arising in PSR J11416545, unless the emission is patchy.Comment: Accepted for publication in Astrophysical Journal Letter
Chemical Heterogeneity of a Large Cluster IDP: Clues to its Formation History Using X-ray Fluorescence Mapping and XANES Spectroscopy
Chondritic porous IDPs may be among the most primitive objects found in our solar system [1]. They consist of many micron to submicron minerals, glasses and carbonaceous matter [2,3,4,5,6,7] with > 10(exp 4) grains in a 10 micron cluster [8]. Speculation on the environment where these fine grained, porous IDPs formed varies with possible sources being presolar dusty plasma clouds, protostellar condensation, solar asteroids or comets [4,6,9]. Also, fine grained dust forms in our solar system today [10,11]. Isotopic anomalies in some particles in IDPs suggest an interstellar source[4,7,12]. IDPs contain relic particles left from the dusty plasma that existed before the protostellar disk formed and other grains in the IDPs formed later after the cold dense nebula cloud collapsed to form our protostar and other grains formed more recently. Fe and CR XANES spectroscopy is used here to investigate the oxygen environment in a large (>50 10 micron or larger sub-units) IDP. Conclusions: Analyzing large (>50 10 micron or larger sub-units) CP IDPs gives one a view on the environments where these fine dust grains formed which is different from that found by only analyzing the small, 10 micron IDPs. As with cluster IDP L2008#5 [3], L2009R2 cluster #13 appears to be an aggregate of grains that sample a diversity of solar and perhaps presolar environments. Sub-micron, grain by grain measurement of trace element contents and elemental oxidation states determined by XANES spectroscopy offers the possibility of understanding the environments in which these grains formed when compared to standard spectra. By comparing thermodynamic modeling of condensates with analytical data an understanding of transport mechanisms operating in the early solar system may be attained
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