3,191 research outputs found
Methods of Treating and Preventing Tall Fescue Toxicosis by the Administration of Thiamin
A method of treating and effectively alleviating the symptoms of tall fescue toxicosis in domestic farm animals includes the administering of thiamin at therapeutic levels into the feed for the animals. A method of preventing tall fescue toxicosis in animals grazing or feeding on endophyte infected tall fescue is also provided
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Biogeochemical Changes During Bio-cementation Mediated by Stimulated and Augmented Ureolytic Microorganisms.
Microbially Induced Calcite Precipitation (MICP) is a bio-mediated cementation process that can improve the engineering properties of granular soils through the precipitation of calcite. The process is made possible by soil microorganisms containing urease enzymes, which hydrolyze urea and enable carbonate ions to become available for precipitation. While most researchers have injected non-native ureolytic bacteria to complete bio-cementation, enrichment of native ureolytic microorganisms may enable reductions in process treatment costs and environmental impacts. In this study, a large-scale bio-cementation experiment involving two 1.7-meter diameter tanks and a complementary soil column experiment were performed to investigate biogeochemical differences between bio-cementation mediated by either native or augmented (Sporosarcina pasteurii) ureolytic microorganisms. Although post-treatment distributions of calcite and engineering properties were similar between approaches, the results of this study suggest that significant differences in ureolysis rates and related precipitation rates between native and augmented microbial communities may influence the temporal progression and spatial distribution of bio-cementation, solution biogeochemical changes, and precipitate microstructure. The role of urea hydrolysis in enabling calcite precipitation through sustained super-saturation following treatment injections is explored
Three Numerical Puzzles and the Top Quark's Chiral Weak-Moment
Versus the standard model's t --> W b decay helicity amplitudes, three
numerical puzzles occur at the 0.1 % level when one considers the amplitudes in
the case of an additional (f_M + f_E) coupling of relative strength 53 GeV. The
puzzles are theoretical ones which involve the t --> W b decay helicity
amplitudes in the two cases, the relative strength of this additional coupling,
and the observed masses of these three particles. A deeper analytic realization
is obtained for two of them. Equivalent realizations are given for the
remaining one. An empirical consequence of these analytic realizations is that
it is important to search for effects of a large chiral weak-moment of the
top-quark, the effective mass-scale is about 53 GeV. A full theoretical
resolution would include relating the origin of such a chiral weak-moment and
the mass generation of the top-quark, the W-boson, and probably the b-quark.Comment: 18 pages, 1 postscript table (revised to better explain notation,
model #1, add a little material...
Importance of Tests for the Complete Lorentz Structure of the t --> W+ b vertex at Hadron Colliders
The most general Lorentz-invariant decay-density-matrix for , or for , is expressed in terms
of eight helicity parameters. The parameters are physically defined in terms of
partial-width-intensities for polarized-final-states in decay.
The parameters are the partial width, the quark's chirality parameter
, the polarimetry parameter , a "pre-SSB" test parameter
, and four - interference parameters , ,
, which test for violation. They can be
used to test for non-CKM-type CP violation, anomalous 's, top
weak magnetism, weak electricity, and second-class currents. By stage-two
spin-correlation techniques, percent level statistical uncertainites are
typical for measurements at the Tevatron, and several mill level uncertainites
are typical at the LHC.Comment: Minor clarifications. Expression for r_{+-} corrected. 19 pages LaTex
+ Tables + 1 Figur
The effect of catecholaminergic depletion within the prelimbic and infralimbic medial prefrontal cortex on recognition memory for recency, location, and objects
There is good evidence that the medial prefrontal cortex (mPFC) is involved in different aspects of recognition memory. However, the mPFC is a heterogeneous structure, and the contribution of the prelimbic (PL) and infralimbic (IL) cortices to recognition memory has not been investigated. Similarly, the role of different neuromodulators within the mPFC in these processes is poorly understood. To this end, we tested animals with 6-hydroxydopamine (6-OHDA) lesions of the PL and IL mPFC on three tests of object recognition memory that required judgments about recency, object location, and object identity. In the recency task, lesions to both PL and IL severely impaired animals' ability to differentiate between old (earlier presented) and recently presented familiar objects. Relative to sham and PL animals, the IL lesion also disrupted performance on the object location task. However, both lesions left novel object recognition intact. These data confirm previous reports that the mPFC is not required for discriminations based on the relative familiarity of individual objects. However, these results demonstrate that catecholamines within the PL cortex are crucial for relative recency judgments and suggest a possible role for neural processing within the IL in the integration of information about object locatio
The Origin of the Intrinsic Scatter in the Relation Between Black Hole Mass and Bulge Luminosity for Nearby Active Galaxies
We investigate the origin of the intrinsic scatter in the correlation between
black hole mass (MBH) and bulge luminosity [L(bulge)] in a sample of 45
massive, local (z < 0.35) type~1 active galactic nuclei (AGNs). We derive MBH
from published optical spectra assuming a spherical broad-line region, and
L(bulge) from detailed two-dimensional decomposition of archival optical Hubble
Space Telescope images. AGNs follow the MBH-L(bulge) relation of inactive
galaxies, but the zero point is shifted by an average of \Delta log MBH ~ -0.3
dex. We show that the magnitude of the zero point offset, which is responsible
for the intrinsic scatter in the MBH-L(bulge) relation, is correlated with
several AGN and host galaxy properties, all of which are ultimately related to,
or directly impact, the BH mass accretion rate. At a given bulge luminosity,
sources with higher Eddington ratios have lower MBH. The zero point offset can
be explained by a change in the normalization of the virial product used to
estimate MBH, in conjunction with modest BH growth (~ 10%--40%) during the AGN
phase. Galaxy mergers and tidal interactions appear to play an important role
in regulating AGN fueling in low-redshift AGNs.Comment: To appear in ApJ; 67 pages, 56 figures, 4 tables, version with full
resolution figures at http://users.ociw.edu/mjkim/papers/scatter.pd
The Use of a Satellite Communications System for Command and Control of the National Aeronautics and Space Administration Surrogate Unmanned Aerial System Research Aircraft
The NASA Langley Research Center has transformed a Cirrus Design SR22 general aviation (GA) aircraft into an Unmanned Aerial Systems (UAS) Surrogate research aircraft which has served for several years as a platform for unmanned systems research and development. The aircraft is manned with a Safety Pilot and a Research Systems Operator (RSO) that allows for flight operations almost any-where in the national airspace system (NAS) without the need for a Federal Aviation Administration (FAA) Certificate of Authorization (COA). The UAS Surrogate can be remotely controlled from a modular, transportable ground control station (GCS) like a true UAS. Ground control of the aircraft is accomplished by the use of data links that allow the two-way passage of the required data to control the aircraft and provide the GCS with situational awareness. The original UAS Surrogate data-link system was composed of redundant very high frequency (VHF) data radio modems with a maximum range of approximately 40 nautical miles. A new requirement was developed to extend this range beyond visual range (BVR). This new requirement led to the development of a satellite communications system that provided the means to command and control the UAS Surrogate at ranges beyond the limits of the VHF data links. The system makes use of the Globalstar low earth orbit (LEO) satellite communications system. This paper will provide details of the development, implementation, and flight testing of the satellite data communications system on the UAS Surrogate research aircraft
Pesticide Ground Water Monitoring Project Phase VIII
During Phase VIII monitoring (March 24, 2000 to June 30, 2001 ), 86 samples were collected from 77 new wells and 9 samples were collected from wells with previous detectable herbicide
Prevalence of Potentially Morally Injurious Events in Operationally Deployed Canadian Armed Forces Members
Folding Langmuir Monolayers
The maximum pressure a two-dimensional surfactant monolayer is able to
withstand is limited by the collapse instability towards formation of
three-dimensional material. We propose a new description for reversible
collapse based on a mathematical analogy between the formation of folds in
surfactant monolayers and the formation of Griffith Cracks in solid plates
under stress. The description, which is tested in a combined microscopy and
rheology study of the collapse of a single-phase Langmuir monolayer of
2-hydroxy-tetracosanoic acid (2-OH TCA), provides a connection between the
in-plane rheology of LM's and reversible folding
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