8,073 research outputs found
Crop phenology literature review for corn, soybean, wheat, barley, sorghum, rice, cotton, and sunflower
There are no author-identified significant results in this report
Supersymmetric Yang-Mills and Supergravity Amplitudes at One Loop
By applying the known expressions for SYM and SUGRA tree amplitudes, we write
generating functions for the NNMHV box coefficients of SYM as well as the MHV,
NMHV, and NNMHV box coefficients for SUGRA. The all-multiplicity generating
functions utilize covariant, on-shell superspace whereby the contribution from
arbitrary external states in the supermultiplet can be extracted by Grassmann
operators. In support of the relation between dual Wilson loops and SYM
scattering amplitudes at weak coupling, the SYM amplitudes are presented in a
manifestly dual superconformal form. We introduce ordered box coefficients for
calculating SUGRA quadruple cuts and prove that ordered coefficients generate
physical cut amplitudes after summing over permutations of the external legs.
The ordered box coefficients are produced by sewing ordered subamplitudes,
previously used in applying on-shell recursion relations at tree level. We
describe our verification of the results against the literature, and a formula
for extracting the contributions from external gluons or gravitons to NNMHV
superamplitudes is presented.Comment: 46 pages, 2 figures, additional references and clarifications
include
Tree-level Split Helicity Amplitudes in Ambitwistor Space
We study all tree-level split helicity gluon amplitudes by using the recently
proposed BCFW recursion relation and Hodges diagrams in ambitwistor space. We
pick out the contributing diagrams and find that all of them can be divided
into triangles in a suitable way. We give the explicit expressions for all of
these amplitudes. As an example, we reproduce the six gluon split NMHV
amplitudes in momentum space.Comment: 20 pages, 16 figures; minor changes; clarifications added, 22 pages,
16 figure
Crop yield literature review for AgRISTARS crops: Corn, soybeans, wheat, barley, sorghum, rice, cotton, and sunflowers
There are no author-identified significant results in this report
Magnetic properties of Yb2Mo2O7 and Gd2Mo2O7 from rare earth Mossbauer measurements
Using 170-Yb and 155-Gd Mossbauer measurements down to 0.03K, we have
examined the semiconducting pyrochlore Yb2Mo2O7 where the Mo intra-sublattice
interaction is anti-ferromagnetic and the metallic pyrochlore Gd2Mo2O7 where
this interaction is ferromagnetic. Additional information was obtained from
susceptibility, magnetisation and 172-Yb perturbed angular correlation
measurements. The microscopic measurements evidence lattice disorder which is
important in Yb2Mo2O7 and modest in Gd2Mo2O7. Magnetic irreversibilities occur
at 17K in Yb2Mo2O7 and at 75K in Gd2Mo2O7 and below these temperatures the rare
earths carry magnetic moments which are induced through couplings with the Mo
sublattice. In Gd2Mo2O7, we observe the steady state Gd hyperfine populations
at 0.027K are out of thermal equilibrium, indicating that Gd and Mo spin
fluctuations persist at very low temperatures. Frustration is thus operative in
this essentially isotropic pyrochlore where the dominant Mo intra-sublattice
interaction is ferromagnetic.Comment: 9 pages, 9 figure
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Study of an outbreak of Prostephanus truncatus (Horn) in Tanzania. Report of the Tropical Products Institute (G164)
A comprehensive survey of the Tabora region of Tanzania was undertaken to observe the distribution of Prostephanus truncatus (the greater grain borer), a pest of stored maize. The pest was found in grain stores in 46 villages from a total of 56 examined, in all four districts of the region, being absent only in eastern lgunga, a sorghum-growing area, and in the southern part of the Taoora district. The pest was found in the Shinyanga region and in markets in the Mwanza region and at stores at Kilosa in the Morogoro region. After 4-6 months storage, maize samples collected from the villages in the Tabora region exhibited as much as 34% weight loss. Damage on this scale in a period of very dry weather, in very dry maize (average 11.2% moisture content) is extraordinarily high and demonstrates the destructive nature of this pest. Without doubt the pest will cause both a serious and widespread grain shortage in the region later and a dearth of seed grain for the coming growing season. Besides attacking maize, the pest also heavily damaged cassava and, to a lesser extent, other commodities such as groundnuts. Wooden implements and storage structures were also damaged. From the survey it is concluded that P. truncatus has become very well established in West Central Tanzania and is of major importance as a pest of stored produce. The outbreak must be seen to be of grave significance to the region. Unless effective measures to control and contain it are rigidly enforced the pest will spread throughout the rest of the country. The beetle poses a very real threat throughout East and Central Africa. Insecticide trials were established to assess the effectiveness of different treatments for the control of this pest in farm storage. These trials will continue. This account of the investigation was prepared whilst the team was in Tanzania. It was presented together with specific recommendations for the control and containment of the infestation at a final meeting between the team and the Ministry of Agriculture. The Tanzanian authorities have already taken steps to inform the international community through the FAO. They also agreed that the scientific results of the investigation could be made generally available
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