1,674 research outputs found

    A Direct Reputation Model for VO Formation

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    We show that reputation is a basic ingredient in the Virtual Organisation (VO) formation process. Agents can use their experiences gained in direct past interactions to model other’s reputation and deciding on either join a VO or determining who is the most suitable set of partners. Reputation values are computed using a reinforcement learning algorithm, so agents can learn and adapt their reputation models of their partners according to their recent behaviour. Our approach is especially powerful if the agent participates in a VO in which the members can change their behaviour to exploit their partners. The reputation model presented in this paper deals with the questions of deception and fraud that have been ignored in current models of VO formation

    Content of bioactive compounds and their contribution to antioxidant capacity during ripening of pineapple (Ananas comosus L.) cv Esmeralda

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    Pineapple (Ananas comosus L.) cv Esmeralda is a commercially important fruit with many bioactive compounds like vitamin C, β-carotene, phenolic compounds and flavonoids, which have been reported only for fruits of commercial maturity. Our objective was to evaluate changes in concentration of main pineapple bioactives, their contribution to total antioxidant capacity and enzyme activities of phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) during pineapple ripening. Fruits were grouped into four ripening stages (RS) according to their weight, size and percentage of yellow skin color (RS1: 100% green, RS2: up to 30% yellow, RS3: 30% - 75% yellow, RS4: 75% - 100% yellow). Vitamin C content initially increased, and decreased at RS4; β-carotene, phenolics and antioxidant capacity increased gradually. Phenolics contributed over 40% of antioxidant capacity, followed by vitamin C and β-carotene. Major phenolic compounds identified were gallic acid, catechin and epicatechin. PAL and POD activity increased with ripening and correlated with concentration of phenolics. No PPO activity was quantified. We concluded that ripening of pineapple cv Esmeralda alters the concentration of bioactive compounds. Phenolic compounds, particularly gallic acid, exert the most antioxidant capacity during all RS, even if other compounds have higher concentrations

    Morphological Study and Dielectric Behavior of Nonisothermally Crystallized Poly(ethylene naphthalate) Nanocomposites as a Function of Graphene Content

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    Morphological evolution and dielectric properties of poly(ethylene naphthalate)- (PEN-) graphene nanocomposites nonisothermally crystallized have been investigated. PEN-graphene nanocomposites containing 0.01, 0.025, 0.05, 0.075, and 0.1 wt% of graphene were prepared by melt blending in a mini twin screw extruder. The results showed that graphene exhibited a superior influence on morphological and conformational structure of PEN during nonisothermal crystallization at low graphene contents. Crystallization temperature (Tc) was found to be increased up to 18°C supporting the high nucleating activity of graphene layers. Wide angle X-ray diffraction (WAXD) and Fourier Transform Infrared Spectroscopy (FTIR) indicated that graphene modifies the conformation of PEN chains promoting crystallinity and favoring the evolution from α to β crystalline form with homogeneous lamellar thickness. It may be attributed to the structural similarity between naphthalene rings and graphene structure and to π-π interactions during nucleation. Dielectric behavior was found to be a function of graphene content where the nanocomposites changed from dielectric to low conducting material when passing from 0.075 to 0.1 wt% of graphene content. This phenomenon permits having a wide range of properties to fit a wide variety of applications required to store electrical energy of low voltage

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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