2,299 research outputs found

    Labile reducing materials found in wheat flour

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    LD2668 .T4 1942 M9Master of Scienc

    LASR-Guided Stellar Photometric Variability Subtraction: The Linear Algorithm For Significance Reduction

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    We develop a technique for removing stellar variability in the light curves of δ\delta-Scuti and similar stars. Our technique, which we name the Linear Algorithm for Significance Reduction (LASR), subtracts oscillations from a time series by minimizing their statistical significance in frequency space. We demonstrate that LASR can subtract variable signals of near-arbitrary complexity and can robustly handle close frequency pairs and overtone frequencies. We demonstrate that our algorithm performs an equivalent fit as prewhitening to the straightforward variable signal of KIC 9700322. We also show that LASR provides a better fit to seismic activity than prewhitening in the case of the complex δ\delta-Scuti KOI-976.Comment: 9 pages, 5 figures, accepted for publication in Astronomy & Astrophysics. Pseudocode and github link to code included in manuscrip

    Inter-temporal changes in ethnic urban earnings disparities in China

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    Chapter from: 'Rising Inequality in China: Challenge to a Harmonious Society', edited by Shi Li, Hiroshi Sato and Terry Sicular

    Renormalization of Boundary Fermions and World-Volume Potentials on D-branes

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    We consider a sigma model formulation of open string theory with boundary fermions carrying Chan-Paton charges at the string ends. This formalism is particularly suitable for studying world-volume potentials on D-branes. We perform explicit two-loop sigma model computations of the potential T-dual to the non-abelian Born-Infeld action. We also discuss the world-volume couplings of NS fluxes which are responsible for Myers' dielectric effect.Comment: 17 pages, 8 figure

    Automatic partitioning of database applications

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    Database-backed applications are nearly ubiquitous in our daily lives. Applications that make many small accesses to the database create two challenges for developers: increased latency and wasted resources from numerous network round trips. A well-known technique to improve transactional database application performance is to convert part of the application into stored procedures that are executed on the database server. Unfortunately, this conversion is often difficult. In this paper we describe Pyxis, a system that takes database-backed applications and automatically partitions their code into two pieces, one of which is executed on the application server and the other on the database server. Pyxis profiles the application and server loads, statically analyzes the code's dependencies, and produces a partitioning that minimizes the number of control transfers as well as the amount of data sent during each transfer. Our experiments using TPC-C and TPC-W show that Pyxis is able to generate partitions with up to 3x reduction in latency and 1.7x improvement in throughput when compared to a traditional non-partitioned implementation and has comparable performance to that of a custom stored procedure implementation.National Science Foundation (U.S.). Graduate Research Fellowshi

    The Effects of Inorganic Nitrogen form and CO2CO_2 Concentration on Wheat Yield and Nutrient Accumulation and Distribution

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    Inorganic N is available to plants from the soil as ammonium (NH4+NH^+_4) and nitrate (NO3NO^-_3). We studied how wheat grown hydroponically to senescence in controlled environmental chambers is affected by N form (NH4+NH^+_4 vs. NO3NO^-_3) and CO2CO_2 concentration (“subambient,” “ambient,” and “elevated”) in terms of biomass, yield, and nutrient accumulation and partitioning. Wheat supplied with NH4+NH^+_4 as a sole N source had the strongest response to CO2CO_2 concentration. Plants exposed to subambient and ambient CO2CO_2 concentrations typically had the greatest biomass and nutrient accumulation under both N forms. In general NH4+NH^+_4-supplied plants had higher concentrations of total N, P, K, S, Ca, Zn, Fe, and Cu, while NO3NO^-_3-supplied plants had higher concentrations of Mg, B, Mn, and NO3NO^-_3 - N. NH4+NH^+_4-supplied plants contained amounts of phytate similar to NO3NO^-_3-supplied plants but had higher bioavailable Zn, which could have consequences for human health. NH4+NH^+_4-supplied plants allocated more nutrients and biomass to aboveground tissues whereas NO3+NO^+_3-supplied plants allocated more nutrients to the roots. The two inorganic nitrogen forms influenced plant growth and nutrient status so distinctly that they should be treated as separate nutrients. Moreover, plant growth and nutrient status varied in a non-linear manner with atmospheric CO2CO_2 concentration

    Advanced aeroservoelastic stabilization techniques for hypersonic flight vehicles

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    Advanced high performance vehicles, including Single-Stage-To-Orbit (SSTO) hypersonic flight vehicles, that are statically unstable, require higher bandwidth flight control systems to compensate for the instability resulting in interactions between the flight control system, the engine/propulsion dynamics, and the low frequency structural modes. Military specifications, such as MIL-F-9490D and MIL-F-87242, tend to limit treatment of structural modes to conventional gain stabilization techniques. The conventional gain stabilization techniques, however, introduce low frequency effective time delays which can be troublesome from a flying qualities standpoint. These time delays can be alleviated by appropriate blending of gain and phase stabilization techniques (referred to as Hybrid Phase Stabilization or HPS) for the low frequency structural modes. The potential of using HPS for compensating structural mode interaction was previously explored. It was shown that effective time delay was significantly reduced with the use of HPS; however, the HPS design was seen to have greater residual response than a conventional gain stablized design. Additional work performed to advance and refine the HPS design procedure, to further develop residual response metrics as a basis for alternative structural stability specifications, and to develop strategies for validating HPS design and specification concepts in manned simulation is presented. Stabilization design sensitivity to structural uncertainties and aircraft-centered requirements are also assessed
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