8,344 research outputs found
Research Notes : United States : Soybean floral ecology and insect pollination
The cultivated soybean (Glycine max (L.) Merrill) is an herbaceous annual, unknown in the wild, with uncertain ancestry. Most believe that its origin was in Eastern Asia, probably Northeastern China, where it was first cultivated about the 11th century B.C. (Probst and Judd, 1973). Like corn, the soybean may have been selected and bred by ancient man from a more primi-tive form that was different in growth habit and floral development
Evaluation of insulation materials and composites for use in a nuclear radiation environment, phase 2
The nuclear heating of the propellant in all of the four baseline RNS configurations studied was much lower than that of the nuclear flight module configuration with the 5000-MW NERVA analyzed previously. Although the nuclear heating has been reduced, the effect of nuclear heating on the propellant as well as the effect of nuclear heating on internal structures such as antivortex baffles, screens, and sump components cannot be neglected. In addition, it was found that the present analytical precedures were not able to predict boundary layer initiation and breakoff points with the accuracy necessary to predict propellant thermodynamic nonequilibrium (stratification) and/or mixing
The ionization structure of the Orion nebula: Infrared line observations and models
Observations of the (O III) 52 and 88 micron lines and the (N III) 57 micron line have been made at 6 positions and the (Ne III) 36 micron line at 4 positions in the Orion Nebula to probe its ionization structure. The measurements, made with a -40" diameter beam, were spaced every 45" in a line south from and including the Trapezium. The wavelength of the (Ne III) line was measured to be 36.013 + or - 0.004 micron. Electron densities and abundance ratios of N(++)/O(++) have been calculated and compared to other radio and optical observations. Detailed one component and two component (bar plus halo) spherical models were calculated for exciting stars with effective temperatures of 37 to 40,000K and log g = 4.0 and 4.5. Both the new infrared observations and the visible line measurements of oxygen and nitrogen require T sub eff approx less than 37,000K. However, the double ionized neon requires a model with T sub eff more than or equal to 39,000K, which is more consistent with that inferred from the radio flux or spectral type. These differences in T sub eff are not due to effects of dust on the stellar radiation field, but are probably due to inaccuracies in the assumed stellar spectrum. The observed N(++)/O(++) ratio is almost twice the N(+)/O(+) ratio. The best fit models give N/H = 8.4 x 10 to the -5 power, O/H = 4.0 x 10 to the -4 power, and Ne/H = 1.3 x 10 to the -4 power. Thus neon and nitrogen are approximately solar, but oxygen is half solar in abundance. From the infrared O(++) lines it is concluded that the ionization bar results from an increase in column depth rather than from a local density enhancement
Laboratory tests of field crop seeds as indicators of seeding value
Laboratory analysis and tests of seed samples were originally undertaken by governmental agencies in the United States and other countries to inform farmers concerning the weed seed content and plant producing capacity of seed lots. The determination of seed purity and the detection of seeds of noxious weeds have not proved difficult provided that representative samples of seed are submitted. Illustrations of weed seeds in bulletins and books, together with the use of herbarium specimens, have made it possible\u27 to identify with some degree of certainty foreign seeds found in crop seeds. Efforts to measure the plant producing capacity of seed lots have been less successful than to identify weed and crop seeds, because of (a) a lack of knowledge as to the factors affecting the viability and germination of many kinds of seeds, (b) difficulty of interpreting what constitutes normal germination and (c) inability to interpret the value of impermeable legume seeds in obtaining and maintaining field stands
Airborne Astronomy Symposium. A symposium commemorating the tenth anniversary of operations of the Kuiper Airborne Observatory
Airborne infrared astronomy is discussed with respect to observations of the solar system, stars, star formation, and the interstellar medium. Far infrared characteristics of the Milky Way, its center, and other galaxies are considered. The instrumentation associated with IR astronomy is addressed
A theoretical approach to nursing assessment
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73763/1/j.1365-2648.1985.tb00500.x.pd
Spitzer IRS Observations of the Galactic Center: Shocked Gas in the Radio Arc Bubble
We present Spitzer IRS spectra (R ~600, 10 - 38 micron) of 38 positions in
the Galactic Center (GC), all at the same Galactic longitude and spanning
plus/minus 0.3 degrees in latitude. Our positions include the Arches Cluster,
the Arched Filaments, regions near the Quintuplet Cluster, the ``Bubble'' lying
along the same line-of-sight as the molecular cloud G0.11-0.11, and the diffuse
interstellar gas along the line-of-sight at higher Galactic latitudes. From
measurements of the [O IV], [Ne II], [Ne III], [Si II], [S III], [S IV], [Fe
II], [Fe III], and H_2 S(0), S(1), and S(2) lines we determine the gas
excitation and ionic abundance ratios. The Ne/H and S/H abundance ratios are ~
1.6 times that of the Orion Nebula. The main source of excitation is
photoionization, with the Arches Cluster ionizing the Arched Filaments and the
Quintuplet Cluster ionizing the gas nearby and at lower Galactic latitudes
including the far side of the Bubble. In addition, strong shocks ionize gas to
O^{+3} and destroy dust grains, releasing iron into the gas phase (Fe/H ~ 1.3
times 10^{-6} in the Arched Filaments and Fe/H ~ 8.8 times 10^{-6} in the
Bubble). The shock effects are particularly noticeable in the center of the
Bubble, but O is present in all positions. We suggest that the shocks
are due to the winds from the Quintuplet Cluster Wolf-Rayet stars. On the other
hand, the H_2 line ratios can be explained with multi-component models of warm
molecular gas in photodissociation regions without the need for H_2 production
in shocks.Comment: 51 pages, 17 figures To be published in the Astrophysical Journa
Charge Exchange Spectra of Hydrogenic and He-like Iron
We present H-like Fe XXVI and He-like Fe XXV charge-exchange spectra
resulting from collisions of highly charged iron with N2 gas at an energy of 10
eV/amu in an electron beam ion trap. Although individual high-n emission lines
are not resolved in our measurements, we observe that the most likely level for
Fe25+ --> Fe24+ electron capture is n~9, in line with expectations, while the
most likely value for Fe26+ --> Fe25+ charge exchange is significantly higher.
In the Fe XXV spectrum, the K-alpha emission feature dominates, whether
produced via charge exchange or collisional excitation. The K-alpha centroid is
lower in energy for the former case than the latter (6666 versus 6685 eV,
respectively), as expected because of the strong enhancement of emission from
the forbidden and intercombination lines, relative to the resonance line, in
charge-exchange spectra. In contrast, the Fe XXVI high-n Lyman lines have a
summed intensity greater than that of Ly-alpha, and are substantially stronger
than predicted from theoretical calculations of charge exchange with atomic H.
We conclude that the angular momentum distribution resulting from electron
capture using a multi-electron target gas is significantly different from that
obtained with H, resulting in the observed high-n enhancement. A discussion is
presented of the relevance of our results to studies of diffuse Fe emission in
the Galactic Center and Galactic Ridge, particularly with ASTRO-E2/Suzaku.Comment: 16 pages, 4 figures (3 color), accepted by Ap
Effect of Enogen Feed Corn Inclusion in Conventional and Natural Finishing Cattle Diets
Increasing the extent of starch digestibility during finishing could allow producers to improve cattle efficiency. A finishing performance study was conducted to determine the effect of Enogen Feed Corn inclusion as dry-rolled corn and corn silage in comparison to a control corn hybrid within natural and conventional feeding programs for heifers and steers. Cattle in the conventional feeding program received implants and the ration included feed additives, while cattle on the natural program were not implanted and the ration did not contain feed additives. The inclusion of Enogen Feed Corn had no impact on steer or heifer finishing performance. The use of implants and feed additives in the conventional feeding program increased hot carcass weight 12.2% in steers and 7.0% in heifers. When compared to cattle in the natural program, feeding cattle in a conventional program improved feed conversion by 19.4% in steers and 13.0% in heifers
A High Throughput Workflow Environment for Cosmological Simulations
The next generation of wide-area sky surveys offer the power to place
extremely precise constraints on cosmological parameters and to test the source
of cosmic acceleration. These observational programs will employ multiple
techniques based on a variety of statistical signatures of galaxies and
large-scale structure. These techniques have sources of systematic error that
need to be understood at the percent-level in order to fully leverage the power
of next-generation catalogs. Simulations of large-scale structure provide the
means to characterize these uncertainties. We are using XSEDE resources to
produce multiple synthetic sky surveys of galaxies and large-scale structure in
support of science analysis for the Dark Energy Survey. In order to scale up
our production to the level of fifty 10^10-particle simulations, we are working
to embed production control within the Apache Airavata workflow environment. We
explain our methods and report how the workflow has reduced production time by
40% compared to manual management.Comment: 8 pages, 5 figures. V2 corrects an error in figure
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