Five blind men and the elephant: what can the NASA Aura ozone measurements tell us about stratosphere-troposphere exchange?

We examine whether the individual ozone (O<sub>3</sub>) measurements from the four Aura instruments can quantify the stratosphere-troposphere exchange (STE) flux of O<sub>3</sub>, an important term of the tropospheric O<sub>3</sub> budget. The level 2 (L2) Aura swath data and the nearly coincident ozone sondes for the years 2005–2006 are compared with the 4-D, high-resolution (1° × 1° × 40-layer × 0.5 h) model simulation of atmospheric ozone for the same period from the University of California, Irvine chemistry transport model (CTM). The CTM becomes a transfer standard for comparing individual profiles from these five, not-quite-coincident measurements of atmospheric ozone. Even with obvious model discrepancies identified here, the CTM can readily quantify instrument-instrument biases in the tropical upper troposphere and mid-latitude lower stratosphere. In terms of STE processes, all four Aura datasets have some skill in identifying stratosphere-troposphere folds, and we find several cases where both model and measurements see evidence of high-O<sub>3</sub> stratospheric air entering the troposphere. In many cases identified in the model, however, the individual Aura profile retrievals in the upper troposphere and lower stratosphere show too much noise, as expected from their low sensitivity and coarse vertical resolution at and below the tropopause. These model-measurement comparisons of individual profiles do provide some level of confidence in the model-derived STE O<sub>3</sub> flux, but it will be difficult to integrate this flux from the satellite data alone

Conduction mechanisms of epitaxial EuTiO3 thin films

To investigate leakage current density versus electric field characteristics, epitaxial EuTiO3 thin films were deposited on (001) SrTiO3 substrates by pulsed laser deposition and were post-annealed in a reducing atmosphere. This investigation found that conduction mechanisms are strongly related to temperature and voltage polarity. It was determined that from 50 to 150 K the dominant conduction mechanism was a space-charge-limited current under both negative and positive biases. From 200 to 300 K, the conduction mechanism shows Schottky emission and Fowler-Nordheim tunneling behaviors for the negative and positive biases, respectively. This work demonstrates that Eu3+ is one source of leakage current in EuTiO3 thin films.Comment: 17 pages,4 figures, conferenc

Indirect exchange of magnetic impurities in zigzag graphene ribbon

We use quantum Monte Carlo method to study the indirect coupling between two magnetic impurities on the zigzag edge of graphene ribbon, with respect to the chemical potential $\mu$. We find that the spin-spin correlation between two adatoms located on the nearest sites in the zigzag edge are drastically suppressed around the zero-energy. As we switch the system away from half-filling, the antiferromagnetic correlation is first enhanced and then decreased. If the two adatoms are adsorbed on the sites belonging to the same sublattice, we find similar behavior of spin-spin correlation except for a crossover from ferromagnetic to antiferromagentic correlation in the vicinity of zero-energy. We also calculated the weight of different components of d-electron wave function and local magnet moment for various values of parameters, and all the results are consistent with those of spin-spin correlation between two magnetic impurities.Comment: 3 pages, 4 figures, conference proceedin

Effects of fermented wheat-rice distillers dried grains with solubles on meat quality and amino acid profile in broilers

The aim of this experiment was to evaluate the effects of replacing distillers dried grains with solubles (DDGS) with fermented DDGS (FDDGS) on meat quality and serum amino acid profiles in Chinese yellow broilers. Forty-eight 42-day-old male Chinese yellow broilers were randomly allotted to the treatments. Each treatment was replicated six times with four birds per replicate. Both groups received a basal corn-soybean diet that was supplemented with either 20% DDGS or 20% FDDGS. Broilers were euthanized at 70 days old. The right half of each breast was evaluated for meat quality. Both breast and thigh meats were evaluated for proximate and fatty acid composition. Serum from blood samples was analysed to quantify relative amounts of free amino acids. Breast meat from broilers supplemented with FDDGS had a lower pH and less drip loss than those supplemented with DDGS (P <0.05). No differences were detected between treatments in the proximate composition of breast and thigh meat (P >0.05). Myristic acid (C14:0) concentration of thigh muscles was reduced for broilers supplemented with FDDGS compared with those supplemented with DDGS (P＜0.05). Concentrations of lysine, taurine, alpha-aminoadipic acid, glycine, and 3-methylhistidine in serum were all lower for broilers supplemented with FDDGS than for those supplemented with DDGS (P＜ 0.05). Meanwhile, the serum phosphoserine concentration of the FFDS-supplemented broilers was greater than those supplemented with DDGS (P＜0.05). In conclusion, replacing 20% DDGS with a like amount of FDDGS can be recommended for diets of growing broiler chickens.Keywords: fatty acids, meat quality, shear forc