Slow light in molecular aggregates nanofilms

We study slow light performance of molecular aggregates arranged in nanofilms by means of coherent population oscillations (CPO). The molecular cooperative behavior inside the aggregate enhances the delay of input signals in the GHz range in comparison with other CPO-based devices. Moreover, the problem of residual absorption present in CPO processes, is removed. We also propose an optical switch between different delays by exploiting the optical bistability of these aggregates.Comment: 4 pages, 4 figure

Effect of Urea and Distillers Inclusion in Dry- Rolled Corn Based Diets on Heifer Performance and Carcass Characteristics

Crossbred heifers (n=96, BW = 810 ± 20) were utilized to evaluate the effects of increasing wet distillers grains plus solubles and urea inclusion in a dry rolled corn based finishing diet on performance and carcass characteristics. Heifers were individually fed using a calan gate system with a 2 × 2 factorial arrangement of treatments. Factors included distillers inclusion at either 10 or 20% of diet DM and urea inclusion at either 0.2 or 1.4% of diet DM. Th ere was no difference for final body weight, average daily gain, and feed conversion on a live or carcass adjusted basis for either urea or distillers inclusion in the diet. Dry matter intake was reduced with increased urea inclusion; however, distillers inclusion did not influence intake. Added distillers and urea in the diet had minimal impact on performance suggesting supplemental urea in a dry rolled corn based finishing diets is of minimal benefit when feeding at least 10% distillers grains

Hippocampal Infusion of Zeta Inhibitory Peptide Impairs Recent, but Not Remote, Recognition Memory in Rats.

Spatial memory in rodents can be erased following the infusion of zeta inhibitory peptide (ZIP) into the dorsal hippocampus via indwelling guide cannulas. It is believed that ZIP impairs spatial memory by reversing established late-phase long-term potentiation (LTP). However, it is unclear whether other forms of hippocampus-dependent memory, such as recognition memory, are also supported by hippocampal LTP. In the current study, we tested recognition memory in rats following hippocampal ZIP infusion. In order to combat the limited targeting of infusions via cannula, we implemented a stereotaxic approach for infusing ZIP throughout the dorsal, intermediate, and ventral hippocampus. Rats infused with ZIP 3-7 days after training on the novel object recognition task exhibited impaired object recognition memory compared to control rats (those infused with aCSF). In contrast, rats infused with ZIP 1 month after training performed similar to control rats. The ability to form new memories after ZIP infusions remained intact. We suggest that enhanced recognition memory for recent events is supported by hippocampal LTP, which can be reversed by hippocampal ZIP infusion

Late Summer Planted Oat-Brassica Forage Quality Changes during Winter Grazing

Oat, radish, and turnip samples were taken on pivots being grazed from November through January in Clay Center, Nebraska. The objective was to determine how the quality changed throughout the winter. The forage was observed to be high-quality (highly digestibility with moderate CP content). Digestibility did decline over this period but minimal changes in CP content were observed. From early November to early January, the digestibility of oats appeared to decline more (10% unit decline) than turnip and radish leaves (5% unit decrease). However, digestibility (67% IVOMD) and CP content (15%) of oats in early January were still as high as a good quality grass hay. Brassica (radish and turnip) leaves were more similar to a concentrate (81–83% IVOMD and 23–26% CP) even in January. Thus, even though the forage changed color from green to brown after hard freezes, the forage still had good feed value in January

Modeling the Risk of Fire/Explosion Due to Oxidizer/Fuel Leaks in the Ares I Interstage

A significant flight hazard associated with liquid propellants, such as those used in the upper stage of NASA's new Ares I launch vehicle, is the possibility of leakage of hazardous fluids resulting in a catastrophic fire/explosion. The enclosed and vented interstage of the Ares I contains numerous oxidizer and fuel supply lines as well as ignition sources. The potential for fire/explosion due to leaks during ascent depends on the relative concentrations of hazardous and inert fluids within the interstage along with other variables such as pressure, temperature, leak rates, and fluid outgasing rates. This analysis improves on previous NASA Probabilistic Risk Assessment (PRA) estimates of the probability of deflagration, in which many of the variables pertinent to the problem were not explicitly modeled as a function of time. This paper presents the modeling methodology developed to analyze these risks

Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array

We forecast the sensitivity with which the Murchison Widefield Array (MWA) can measure the 21 cm power spectrum of cosmic hydrogen, using radiative transfer simulations to model reionization and the 21 cm signal. The MWA is sensitive to roughly a decade in scale (wavenumbers of k ~ 0.1 - 1 h Mpc^{-1}), with foreground contamination precluding measurements on larger scales, and thermal detector noise limiting the small scale sensitivity. This amounts primarily to constraints on two numbers: the amplitude and slope of the 21 cm power spectrum on the scales probed. We find, however, that the redshift evolution in these quantities can yield important information about reionization. Although the power spectrum differs substantially across plausible models, a generic prediction is that the amplitude of the 21 cm power spectrum on MWA scales peaks near the epoch when the intergalactic medium (IGM) is ~ 50% ionized. Moreover, the slope of the 21 cm power spectrum on MWA scales flattens as the ionization fraction increases and the sizes of the HII regions grow. Considering detection sensitivity, we show that the optimal MWA antenna configuration for power spectrum measurements would pack all 500 antenna tiles as close as possible in a compact core. The MWA is sensitive enough in its optimal configuration to measure redshift evolution in the slope and amplitude of the 21 cm power spectrum. Detecting the characteristic redshift evolution of our models will confirm that observed 21 cm fluctuations originate from the IGM, and not from foregrounds, and provide an indirect constraint on the volume-filling factor of HII regions during reionization. After two years of observations under favorable conditions, the MWA can constrain the filling factor at an epoch when ~ 0.5 to within roughly +/- 0.1 at 2-sigma.Comment: 14 pages, 9 figures, submitted to Ap

Effect of thermal processing practices on the properties of superplastic Al-Li alloys

The effect of thermal processing on the mechanical properties of superplastically formed structural components fabricated from three aluminum-lithium alloys was evaluated. The starting materials consisted of 8090, 2090, and X2095 (Weldalite(TM) 049), in the form of commercial-grade superplastic sheet. The experimental test matrix was designed to assess the impact on mechanical properties of eliminating solution heat treatment and/or cold water quenching from post-forming thermal processing. The extensive hardness and tensile property data compiled are presented as a function of aging temperature, superplastic strain and temper/quench rate for each alloy. The tensile properties of the materials following superplastic forming in two T5-type tempers are compared with the baseline T6 temper. The implications for simplifying thermal processing without degradation in properties are discussed on the basis of the results

Submillimetre dust polarisation and opacity in the HD163296 protoplanetary ring system

We present ALMA images of the sub-mm continuum polarisation and spectral index of the protoplanetary ringed disk HD163296. The polarisation fraction at 870{\mu}m is measured to be ~0.9% in the central core and generally increases with radius along the disk major axis. It peaks in the gaps between the dust rings, and the largest value (~4%) is found between rings 1 and 2. The polarisation vectors are aligned with the disk minor axis in the central core, but become more azimuthal in the gaps, twisting by up to +/-9degrees in the gap between rings 1 and 2. These general characteristics are consistent with a model of self-scattered radiation in the ringed structure, without requiring an additional dust alignment mechanism. The 870/1300{\mu}m dust spectral index exhibits minima in the centre and the inner rings, suggesting these regions have high optical depths. However, further refinement of the dust or the disk model at higher resolution is needed to reproduce simultaneously the observed degree of polarisation and the low spectral index.Comment: 5 pages +2 pages supplemental data. v2 - revised figures and final values; conclusions unchange

Teratogen-Induced Oxidative Stress Targets Glyceraldehyde-3-Phosphate Dehydrogenase in the Organogenesis Stage Mouse Embryo

Exposure during the organogenesis stage of the mouse embryo to the model teratogen, hydroxyurea (HU), induces curly tail and limb malformations. Oxidative stress contributes to the developmental toxicity of HU. Reactive oxygen species (ROS) interact with polyunsaturated bilipid membranes to form α,β-unsaturated reactive aldehydes; 4-hydroxy-2-nonenal (4-HNE), one of the most cytotoxic of these aldehydes, covalently adducts with proteins, lipids, and nucleic acids. The goal of the current study is to determine if HU exposure of CD1 mice on gestation day 9 generates region-specific 4-HNE-protein adducts in the embryo and to identify the proteins targeted. The formation of 4-HNE-protein adducts was elevated in the caudal region of control embryos; HU exposure further increased 4-HNE-protein adduct formation in this area. Interestingly, three of the 4-HNE–modified proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamate oxaloacetate transaminase 2, and aldolase 1, A isoform, are involved in energy metabolism. The formation of 4-HNE-GAPDH protein adducts reduced GAPDH enzymatic activity by 20% and attenuated lactate production by 40%. Furthermore, HU exposure induced the nuclear translocation of GAPDH in the caudal region of exposed embryos; this nuclear translocation may be associated with the reactivation of oxidized proteins involved in DNA repair, such as apurinic/apyrimidinic endonuclease-1, and the stimulation of E1A-associated P300 protein/creb-binding protein (p300/CBP) activity, initiating cell death in a p53-dependent pathway. We propose that GAPDH is a redox-sensitive target in the embryo and may play a role in a stress response during development