1,193 research outputs found
New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV
We present a new measurement of the cosmic-ray positron fraction at energies
between 5 and 15 GeV with the balloon-borne HEAT-pbar instrument in the spring
of 2000. The data presented here are compatible with our previous measurements,
obtained with a different instrument. The combined data from the three HEAT
flights indicate a small positron flux of non-standard origin above 5 GeV. We
compare the new measurement with earlier data obtained with the HEAT-e+-
instrument, during the opposite epoch of the solar cycle, and conclude that our
measurements do not support predictions of charge sign dependent solar
modulation of the positron abundance at 5 GeV.Comment: accepted for publication in PR
Floodplain Mapping In Georgia Using Digital Orthophoto Quarter Quadrangle Base Maps
Proceedings of the 2003 Georgia Water Resources Conference, held April 23-24, 2003, at the University of Georgia.The U.S. Geological Survey (USGS), in cooperation with the Georgia Emergency Management Agency, is working to develop a new base map for mapping flood hazards using color-infrared (CIR), Digital Orthophoto Quarter Quadrangle (DOQQ) imagery now available for the State of Georgia. Approximately 4,000 quarter quadrangles are needed to provide full coverage for the State of Georgia
An experiment for the measurement of the bound-beta decay of the free neutron
The hyperfine-state population of hydrogen after the bound-beta decay of the
neutron directly yields the neutrino left-handedness or a possible right-handed
admixture and possible small scalar and tensor contributions to the weak force.
Using the through-going beam tube of a high-flux reactor, a background free
hydrogen rate of ca. 3 s can be obtained. The detection of the neutral
hydrogen atoms and the analysis of the hyperfine states is accomplished by Lamb
shift source type quenching and subsequent ionization. The constraints on the
neutrino helicity and the scalar and tensor coupling constants of weak
interaction can be improved by a factor of ten.Comment: 9 pages, 5 figures. Submitted to EPJ
Effects of Potential Detoxifying Agents on Growth Performance and Deoxynivalenol (DON) Urinary Balance Characteristics of Nursery Pigs Fed DON-Contaminated Wheat
Two experiments were conducted to evaluate the effects of detoxifying agents on the growth performance of nursery pigs fed diets contaminated with deoxynivalenol (DON). Naturally DON-contaminated wheat (6 ppm) replaced noncontaminated wheat in diets to achieve desired dietary DON concentrations. Basal ingredients were tested for mycotoxin and amino acid content prior to diet manufacturing. Diets were pelleted at 180˚F with a 45-s conditioning time.
A total of 238 barrows and gilts (PIC 327 × 1050; initially 29.6 ± 5.6 lb and 42 d of age) were used in a 21-d growth study. Pens of pigs were allotted by BW to 1 of 5 treatments in a completely randomized design with a 2 × 2 + 1 factorial arrangement. The 5 experimental diets included the following components, 1) positive control (PC; \u3c0.5 mg/kg DON); 2) PC + 1.0% Product X (Nutriquest LLC, Mason City, IA); 3) negative control (NC; 4.0 mg/kg DON); 4) NC + 1.0% Product X; and 5) NC + 1.0% sodium metabisulfite (SMB; Samirian Chemicals, Campbell, CA). There were 6 or 7 replicate pens per treatment and 7 pigs per pen. Chemical analysis indicated a low level of fumonisin (\u3c1 ppm) was present but that all DON concentrations matched calculated values. Analyzed DON concentrations were decreased by 92% when pelleted with SMB. Overall (d 0 to 21), a DON × Product X interaction was observed for ADG (P \u3c 0.05) and ADFI (P \u3c 0.10). Adding Product X to PC diets had no effect on ADG or ADFI; however, when added to NC diets, ADG, and ADFI became worse. As anticipated, DON reduced (P \u3c 0.001) ADG, ADFI, and F/G by 24, 16, and 10%, respectively. Deoxynivalenol-associated reductions in ADG were most distinct (50%) during the initial period (0.42 vs. 0.84 lb from d 0 to 7). Adding SMB to NC diets improved (P \u3c 0.01) ADG, ADFI, and F/G compared to pigs fed the NC alone, and also improved (P \u3c 0.02) ADG and F/G compared to pigs fed PC diets.
A concurrent urinary balance experiment was conducted using diets 3 to 5 from Exp. 1 to evaluate Product X and SMB on DON urinary metabolism. A 10-d adaptation was followed by a 7-d collection using 24 barrows in a randomized complete block design. Pigs fed NC + SMB diet had greater urinary output (P \u3c 0.05) than pigs fed NC + Product X, with NC pigs intermediate. Daily DON excretion was lowest (P \u3c 0.05) in the NC + SMB pigs. However, as a percentage of daily DON intake, NC + SMB fed pigs excreted more DON than they consumed (164%), greater (P \u3c 0.001) than pigs fed the NC (59%) or NC + Product X (48%), and indicative of degradation of DON back to the parent DON molecule. Overall, Product X did not alleviate DON effects on growth nor did it reduce DON absorption and excretion. However, hydrothermally processing DON-contaminated diets with 1.0% SMB restored ADFI and improved F/G. Even so, the urinary balance experiment revealed that some of the converted DON-sulfonate could degrade back to DON under physiological conditions. While SMB appears promising to restore performance in pelleted DON-contaminated diets, additional research needs to address handling and long-term supplementation concerns and to evaluate the stability of the DON-sulfonate conversion
Energy Spectra, Altitude Profiles and Charge Ratios of Atmospheric Muons
We present a new measurement of air shower muons made during atmospheric
ascent of the High Energy Antimatter Telescope balloon experiment. The muon
charge ratio mu+ / mu- is presented as a function of atmospheric depth in the
momentum interval 0.3-0.9 GeV/c. The differential mu- momentum spectra are
presented between 0.3 and about 50 GeV/c at atmospheric depths between 13 and
960 g/cm^2. We compare our measurements with other recent data and with Monte
Carlo calculations of the same type as those used in predicting atmospheric
neutrino fluxes. We find that our measured mu- fluxes are smaller than the
predictions by as much as 70% at shallow atmospheric depths, by about 20% at
the depth of shower maximum, and are in good agreement with the predictions at
greater depths. We explore the consequences of this on the question of
atmospheric neutrino production.Comment: 11 pages, 8 figures, to appear in Phys. Rev. D (2000
The Energy Spectra and Relative Abundances of Electrons and Positrons in the Galactic Cosmic Radiation
Observations of cosmic-ray electrons and positrons have been made with a new
balloon-borne detector, HEAT (the "High-Energy Antimatter Telescope"), first
flown in 1994 May from Fort Sumner, NM. We describe the instrumental approach
and the data analysis procedures, and we present results from this flight. The
measurement has provided a new determination of the individual energy spectra
of electrons and positrons from 5 GeV to about 50 GeV, and of the combined
"all-electron" intensity (e+ + e-) up to about 100 GeV. The single power-law
spectral indices for electrons and positrons are alpha = 3.09 +/- 0.08 and 3.3
+/- 0.2, respectively. We find that a contribution from primary sources to the
positron intensity in this energy region, if it exists, must be quite small.Comment: latex2e file, 30 pages, 15 figures, aas2pp4.sty and epsf.tex needed.
To appear in May 10, 1998 issue of Ap.
Determining the optimal threonine:lysine ratio for the 25 to 50 lb pig
A 21-day growth trial was conducted to determine the threonine: lysine ratio necessary to optimize growth performance of the 25 to 50 Ib pig reared in a high-health, segregated early-weaning (SEW) system. Ten experimental diets, including two levels of lysine (.75% and 1.10% apparent digestible lysine) and five apparent digestible threonine:lysine ratios (40, 47.5, 55, 62.5, and 70%), were used in a 2 x 5 factorial arrangement. Growth performance was improved by feeding 1.10% rather than.75% digestible lysine. Also, results indicated that the apparent digestible threonine requirement for the SEW:-reared, 25 to 50 lb pig is approximately 55% of digestible lysine.; Swine Day, Manhattan, KS, November 21, 199
Interactions among lactose, spray-dried animal plasma, and soybean meal levels may affect segregated early-weaned pigs
Pigs weaned in a segregated early weaning (SEW) environment achieved maximum performance when fed a sequence of diets containing a gradual decrease in spray-dried animal plasma. Furthermore, pigs weaned at approximately 19 days responded positively to 20% soybean meal. Increased levels of lactose enhanced the increases in performance from soybean meal.; Swine Day, Manhattan, KS, November 16, 199
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