26 research outputs found
Partition Functions of Holographic Minimal Models
The partition function of the W_N minimal model CFT is computed in the large
N 't Hooft limit and compared to the spectrum of the proposed holographic dual,
a 3d higher spin gravity theory coupled to massive scalar fields. At finite N,
the CFT contains additional light states that are not visible in the
perturbative gravity theory. We carefully define the large N limit, and give
evidence that, at N = infinity, the additional states become null and decouple
from all correlation functions. The surviving states are shown to match
precisely (for all values of the 't Hooft coupling) with the spectrum of the
higher spin gravity theory. The agreement between bulk and boundary is
partially explained by symmetry considerations involving the conjectured
equivalence between the W_N algebra in the large N limit and the higher spin
algebra of the Vasiliev theory.Comment: 56 page
Multilocation Corn Stover Harvest Effects on Crop Yields and Nutrient Removal
Corn (Zea mays L.) stover was identified as an important feedstock for cellulosic bioenergy production because of the extensive area upon which the crop is already grown. This report summarizes 239 site-years of field research examining effects of zero, moderate, and high stover removal rates at 36 sites in seven different states. Grain and stover yields from all sites as well as N, P, and K removal from 28 sites are summarized for nine longitude and six latitude bands, two tillage practices (conventional vs no tillage), two stover-harvest methods (machine vs calculated), and two crop rotations {continuous corn (maize) vs corn/soybean [Glycine max (L.) Merr.]}. Mean grain yields ranged from 5.0 to 12.0 Mg ha−1 (80 to 192 bu ac−1). Harvesting an average of 3.9 or 7.2 Mg ha−1(1.7 or 3.2 tons ac−1) of the corn stover resulted in a slight increase in grain yield at 57 and 51 % of the sites, respectively. Average no-till grain yields were significantly lower than with conventional tillage when stover was not harvested, but not when it was collected. Plant samples collected between physiological maturity and combine harvest showed that compared to not harvesting stover, N, P, and K removal was increased by 24, 2.7, and 31 kg ha−1, respectively, with moderate (3.9 Mg ha−1) harvest and by 47, 5.5, and 62 kg ha−1, respectively, with high (7.2 Mg ha−1) removal. This data will be useful for verifying simulation models and available corn stover feedstock projections, but is too variable for planning site-specific stover harvest