12,828 research outputs found

    Drip and Mate Operations Acting in Test Tube Systems and Tissue-like P systems

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    The operations drip and mate considered in (mem)brane computing resemble the operations cut and recombination well known from DNA computing. We here consider sets of vesicles with multisets of objects on their outside membrane interacting by drip and mate in two different setups: in test tube systems, the vesicles may pass from one tube to another one provided they fulfill specific constraints; in tissue-like P systems, the vesicles are immediately passed to specified cells after having undergone a drip or mate operation. In both variants, computational completeness can be obtained, yet with different constraints for the drip and mate operations

    Improved zinc oxide thermal control coatings

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    Ferricyanide/ferrocyanide couple prevents zinc oxide pigment degradation in thermal control coatings. Chemical couple retards physical optical property changes

    Priorities, Promoters and Inhibitors in Deterministic Non-Cooperative P Systems

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    Membrane systems (with symbol objects) are distributed controlled multiset processing systems. Non-cooperative P systems with either promoters or inhibitors (of weight not restricted to one) are known to be computationally complete. Since recently, it is known that the power of the deterministic subclass of such systems is subregular. We present new results on the weight of promoters and inhibitors, as well as for characterizing the systems with priorities only

    Low-energy diffraction; a direct-channel point of view: the background

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    We argue that at low-energies, typical of the resonance region, the contribution from direct-channel exotic trajectories replaces the Pomeron exchange, typical of high energies. A dual model realizing this idea is suggested. While at high energies it matches the Regge pole behavior, dominated by a Pomeron exchange, at low energies it produces a smooth, structureless behavior of the total cross section determined by a direct-channel nonlinear exotic trajectory, dual to the Pomeron exchange.Comment: 6 pages, 1 figure. Talk presented at the Second International "Cetraro" Workshop & NATO Advanced Research Workshop "Diffraction 2002", Alushta, Crimea, Ukraine, August 31 - September 6, 200

    Ultrasonic Doppler measurement of renal artery blood flow

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    An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported

    Effect of environment on thermal control coatings

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    Ferrocyanide and ferricyanide additives for prevention of optical degradation of coatings by ultraviolet radiation and vacuu

    Dislocation plasticity in thin metal films

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    This article describes the current level of understanding of dislocation plasticity in thin films and small structures in which the film or structure dimension plays an important role. Experimental observations of the deformation behavior of thin films, including mechanical testing as well as electron microscopy studies, will be discussed in light of theoretical models and dislocation simulations. In particular, the potential of applying strain-gradient plasticity theory to thin-film deformation is discussed. Although the results of all studies presented follow a “smaller is stronger” trend, a clear functional dependence has not yet been established

    Equilibrium orbit analysis in a free-electron laser with a coaxial wiggler

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    An analysis of single-electron orbits in combined coaxial wiggler and axial guide magnetic fields is presented. Solutions of the equations of motion are developed in a form convenient for computing orbital velocity components and trajectories in the radially dependent wiggler. Simple analytical solutions are obtained in the radially-uniform-wiggler approximation and a formula for the derivative of the axial velocity vv_{\|} with respect to Lorentz factor γ\gamma is derived. Results of numerical computations are presented and the characteristics of the equilibrium orbits are discussed. The third spatial harmonic of the coaxial wiggler field gives rise to group IIIIII orbits which are characterized by a strong negative mass regime.Comment: 13 pages, 9 figures, to appear in phys. rev.

    The DVCS Measurement at HERA

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    The recent results of the studies of Deeply Virtual Compton Scattering (DVCS) events at HERA are presented. The possibility offered by this process to gain information about skewed parton distributions (SPD) is emphasized.Comment: Talk given at New Trends in HERA Physics 2001, Ringberg Castle, Tegernsee, Germany, 17-22 Jun 2001, 13 pages, 10 figures, recent ZEUS data discussed, references update

    The Effect of Exogenous Testosterone on Dominance and Status Signaling in the Female American Goldfinch (\u3ci\u3eSpinus tristus\u3c/i\u3e)

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    Studies on aggression and status signaling have traditionally focused on the male sex. As a result, the function of female aggression and status signaling is not nearly as thoroughly understood as it is in males. Although testosterone is characteristically known as a “male hormone,” recent evidence has suggested that in many species females develop testosterone linked fighting potential and ornamentation. In this thesis, I report the results from an investigation on the influence of testosterone on female dominance and status signaling. The female American goldfinch is aggressive year-round over limited resources such as food, and at times females are observed to be more aggressive than males. Additionally, American goldfinches have a dynamic bill color that has been correlated to testosterone and has been shown to serve as a status signal in females. Females were placed into dyads consisting of a testosterone treated individual and a control treated individual of similar dominance. Behavioral observations were recorded over a monopolizable food source, allowing us to determine which female was dominant within each dyad. Additionally, bill color was measured using a spectrophotometer before and after treatment. Although testosterone treated females won a majority of the trials that took place, testosterone did not significantly predict the outcome of the dyad trials. Interestingly, wing size was an accurate predictor of winning, with over 80% of the winners having larger wings. Therefore, it may be that wing was so tightly correlated with winning that it overshadowed our ability to detect any influence of testosterone on competitive potential. Testosterone did not significantly influence bill color in this study. Taken together, these findings indicate that wing size may be a more important mediator of aggression than testosterone within this species
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