2,957 research outputs found

    NUV/Blue spectral observations of sprites in the 320-460 nm region: N2{\mathrm N_2} (2PG) Emissions

    Full text link
    A near-ultraviolet (NUV) spectrograph (320-460 nm) was flown on the EXL98 aircraft sprite observation campaign during July 1998. In this wavelength range video rate (60 fields/sec) spectrographic observations found the NUV/blue emissions to be predominantly N2 (2PG). The negligible level of N2+ (1NG) present in the spectrum is confirmed by observations of a co-aligned, narrowly filtered 427.8 nm imager and is in agreement with previous ground-based filtered photometer observations. The synthetic spectral fit to the observations indicates a characteristic energy of ~1.8 eV, in agreement with our other NUV observations.Comment: 7 pages, 2 figures, 1 table, JGR Space Physics "Effects of Thunderstorms and Lightning in the Upper Atmosphere" Special Sectio

    Ultralight reactive metal foams produced as structural shapes in space: System design

    Get PDF
    This autonomous experiment for foaming metals in space involved: (1) payload support structure; (2) furnace and foaming apparatus; (3) electronic controls; (4) battery power; and (5) metallurgy. Emphasis was laid on a modular design which was easily modifiable and which offered maximum durability, safety, and failure tolerance

    Effect of calf-starter protein solubility on calf performance

    Get PDF
    Three starters containing differently processed protein supplements were fed to Holstein heifer calves, using an early weaning program. One starter contained soybean meal. The other starters contained soybean grits processed through an extrusion cooker to reduce the protein solubility to an intermediate (PDI> 50%) or low (PDI < 15 %) level. Calf performance was similar on all three starters

    Solving Games with Functional Regret Estimation

    Full text link
    We propose a novel online learning method for minimizing regret in large extensive-form games. The approach learns a function approximator online to estimate the regret for choosing a particular action. A no-regret algorithm uses these estimates in place of the true regrets to define a sequence of policies. We prove the approach sound by providing a bound relating the quality of the function approximation and regret of the algorithm. A corollary being that the method is guaranteed to converge to a Nash equilibrium in self-play so long as the regrets are ultimately realizable by the function approximator. Our technique can be understood as a principled generalization of existing work on abstraction in large games; in our work, both the abstraction as well as the equilibrium are learned during self-play. We demonstrate empirically the method achieves higher quality strategies than state-of-the-art abstraction techniques given the same resources.Comment: AAAI Conference on Artificial Intelligence 201

    Overtly anaphoric control in type logical grammar

    Get PDF
    In this paper we analyse anaphoric pronouns in control sentences and we investigate the implications of these kinds of sentences in relation to the Propositional Theory versus Property Theory question. For these purposes, we invoke the categorial calculus with limited contraction, a conservative extension of Lambek calculus that builds contraction into the logical rules for a customized slash type-constructor.Peer ReviewedPostprint (author's final draft

    UV solar irradiance in observations and the NRLSSI and SATIRE-S models

    Full text link
    Total solar irradiance and UV spectral solar irradiance have been monitored since 1978 through a succession of space missions. This is accompanied by the development of models aimed at replicating solar irradiance by relating the variability to solar magnetic activity. The NRLSSI and SATIRE-S models provide the most comprehensive reconstructions of total and spectral solar irradiance over the period of satellite observation currently available. There is persistent controversy between the various measurements and models in terms of the wavelength dependence of the variation over the solar cycle, with repercussions on our understanding of the influence of UV solar irradiance variability on the stratosphere. We review the measurement and modelling of UV solar irradiance variability over the period of satellite observation. The SATIRE-S reconstruction is consistent with spectral solar irradiance observations where they are reliable. It is also supported by an independent, empirical reconstruction of UV spectral solar irradiance based on UARS/SUSIM measurements from an earlier study. The weaker solar cycle variability produced by NRLSSI between 300 and 400 nm is not evident in any available record. We show that although the method employed to construct NRLSSI is principally sound, reconstructed solar cycle variability is detrimentally affected by the uncertainty in the SSI observations it draws upon in the derivation. Based on our findings, we recommend, when choosing between the two models, the use of SATIRE-S for climate studies

    Utilization of near infrared reflectance spectroscopy for prediction of the nutritional composition of beef and pork samples

    Get PDF
    Near-infrared reflectance spectroscopy (NIRS) offers the potential for rapid, low-cost analyses of meat samples. Beef and pork samples were analyzed by both standard laboratory (AOAC) methods and NIRS. Regression equations were developed to relate the two methods. Coefficients of determination between NIRS and AOAC results were .929 for dry matter, .965 for crude protein, and .996 for ether extract. NIRS and AOAC procedures yielded very similar results (DM, 38.82 vs 38.58; CP, 17.78 vs. 17.83; and EE, 18.83 vs. 18.00). NIRS appears to be a rapid and reliable predictor of nutritional composition of ground beef and pork based on regression equations we have developed with a limited number of samples

    Synthesis and reactivity of N-allenyl cyanamides

    Get PDF
    N-Allenyl cyanamides have been accessed via a one-pot deoxycyanamidation–isomerization approach using propargyl alcohol and N-cyano-N-phenyl-p-methylbenzenesulfonamide. The utility of this novel class of allenamide was explored through derivatization, with hydroarylation, hydroamination, and cycloaddition protocols employed to access an array of cyanamide products that would be challenging to access using existing methods

    Leukocyte function and health status of calves supplemented with vitamins A and E

    Get PDF
    Forty-four Holstein calves were fed milk replacers with varied concentrations of vitamins A and E from 3 to 45 d of age to determine their effects on concentrations of plasma vitamin A (retinol and retinyl palmitate) and vitamin E (a- tocopherol), lymphocyte and neutrophil functions, and health of calves. Plasma a-tocopherol was unaffected by increased vitamin A supplementation. Fecal scores, and eye and nose membrane responses were improved with increased vitamin A and lower vitamin E concentration, whereas the same treatment tended to reduce neutrophil cytotoxic and bactericidal activity by 6 wk of age. Increased supplemental vitamin E tended to enhance neutrophil functions. However, age appeared to have an effect on response to both vitamins

    Magnesiate addition/ring-expansion strategy to access the 6-7-6 tricyclic core of hetisine-type C20-diterpenoid alkaloids

    Get PDF
    A synthetic strategy to access the fused 6–7–6 tricyclic core of hetisine-type C20-diterpenoid alkaloids is reported. This strategy employs a Diels–Alder cycloaddition to assemble a fused bicyclic anhydride intermediate, which is elaborated to a vinyl lactone-acetal bearing an aromatic ring in five steps. Aromatic iodination is followed by magnesium–halogen exchange with a trialkyl magnesiate species, which undergoes intramolecular cyclization. Subsequent oxidation provides the desired 6–7–6 tricyclic diketoaldehyde, with carbonyl groups at all three positions for eventual C–N bond formation and subsequent elaboration
    corecore