Planar Two-Loop Five-Parton Amplitudes from Numerical Unitarity

We compute a complete set of independent leading-color two-loop five-parton amplitudes in QCD. These constitute a fundamental ingredient for the next-to-next-to-leading order QCD corrections to three-jet production at hadron colliders. We show how to consistently consider helicity amplitudes with external fermions in dimensional regularization, allowing the application of a numerical variant of the unitarity approach. Amplitudes are computed by exploiting a decomposition of the integrand into master and surface terms that is independent of the parton type. Master integral coefficients are numerically computed in either finite-field or floating-point arithmetic and combined with known analytic master integrals. We recompute two-loop leading-color four-parton amplitudes as a check of our implementation. Results are presented for all independent four- and five-parton processes including contributions with massless closed fermion loops.Comment: v3: corrected wrong signs for five-gluon $N_f^2$ amplitudes with vanishing tree

Soluções da Embrapa em manejo e sistemas de produção de frango de corte.

Projetos:11.11.11.111

Multiresponsive spiropyran-based copolymer: synthesis and characterization

Photochromic copolymers carrying spiropyran side groups have attracted particular attention for potential applications in optical devices, photonic memory and photosensing, as well as, fluorescence imaging.[1] These materials allow overcoming many of the limitations inherent to traditional spiropyran doped polymers, such as, phase separation of the colorant and retardation of the decoloration of the open form.[2] The introduction of light sensitive moieties within responsive polymers has led to the development of sophisticated multiresponsive systems.[3] Block copolymers are important self-assembling systems that can assume a diversity of nanometer-scale morphologies due to the incompatibility and the connectivity constrains between the chemically distinct segments. Therefore, self-assembly of photochromic copolymers in the solid state or in solution allows the development of nanostructured materials. [4] The aim of this research study is the synthesis of a multiresponsive spiropyran-based copolymer, poly(styrene)- co-poly([1´,3´,3´-trimethyl-6-methacryloyloxyspiro(2H-1-benzopyran-2,2´-indoline)]4-vinylbenzoic acid) 2. The functionalized block copolymer poly(styrene)-block-poly(4-vinylbenzoic acid) (PSt-b-P4VBA) 1 synthesized by reversible addition fragmentation chain-transfer (RAFT) polymerization was coupled with 1,3,3-trimethyl-6- hydroxyspiro(2H-1-benzopyran-2,2-indoline). The link between the functionalized block copolymer and spiropyran was successfully obtained by Steglich esterification using DMAP/DCC as catalysts (Scheme 1).n-STeP ProjectNORTE-07-0124-FEDER-000039Programa Operacional Regional do Norte (ON.2)PEst-C/CTM/LA0025/2013 (Strategic Project - LA 25 - 2013-2014

Effect of clay mineral addition on properties of bio-based polymer blends

The effect of clay mineral addition to bio-based blends on morphology and physical properties of thermoplastic starch (TPS) and polypropylene grafted with maleic anhydride (PP-g-MA) was investigated. Blends and nanocomposites containing organoclay, Cloisite 30B, were prepared by melt mixing and characterized by several techniques. X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, STEM) and dynamic mechanical analysis (DMA) demonstrate a very good dispersion of the clay mineral in the polymer matrix, an increase of polymer compatibility and an improvement of mechanical properties. Biodegradation studies performed in compost revealed that Cloisite 30B addition enhanced the matrix biodegradability. Therefore clay minerals, which can be obtained from natural resources, can be efficiently used to improve the properties of bio-based materials and contribute to sustainability.The authors acknowledge the n-STeP - Nanostructured systems for Tail, with reference NORTE-07-0124-FEDER-000039, supported by the Programa Operacional Regional do Norte (ON.2), PEst-C/CTM/LA0025/2013 (Strategic Project - LA 25 - 2013-2014)

Thermoplastic starch-polypropy/lene reinforced with clay

In this study, bio-based blends of thermoplastic starch (TPS) and polypropylene grafted with maleic anhydride (PP-g-MA) without and with organoclay, Cloisite 30B, were prepared in an internal mixer. A TPS-g-PP copolymer was successfully obtained in melt and its formation was confirmed by SEM. The establishment of this copolymer creates an interpenetrating network leading an intercalated/exfoliated clay nanocomposite. Several analytical, angle X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM, STEM) and dynamic mechanical analysis (DMA) were used to characterize the prepared materials. The nanocomposites mechanical properties were improved, showing an increase of about 11% for the nanocomposite when compared with the neat blend. Biodegradation studies performed in compost revealed good percentage of weight loss for the copolymer with clay addition

Development of silver and clay-starch bio-nanocomposites

Starch, among biopolymers is that had the lowest production cost, wide availability, fully biodegradability and is a renewable agriculture resource. Starch due to its sensitivity to humidity and poor mechanical properties cannot be used in many applications. For that, the dispersion of clays in this material improves their physical and mechanical properties, at very low filler loadings. On the other hand, the incorporation of silver nanoparticles into biocompatible and biodegradable matrices gives antimicrobial properties opening a new field for packaging applications. [...

Peanut-shaped bulges in face-on disk galaxies

We present high resolution absorption-line spectroscopy of 3 face-on galaxies, NGC 98, NGC 600, and NGC 1703 with the aim of searching for box/peanut (B/P)-shaped bulges. These observations test and confirm the prediction of Debattista et al. (2005) that face-on B/P-shaped bulges can be recognized by a double minimum in the profile of the fourth-order Gauss-Hermite moment h_4. In NGC 1703, which is an unbarred control galaxy, we found no evidence of a B/P bulge. In NGC 98, a clear double minimum in h_4 is present along the major axis of the bar and before the end of the bar, as predicted. In contrast, in NGC 600, which is also a barred galaxy but lacks a substantial bulge, we do not find a significant B/P shape.Comment: 4 pages, 1 figure. To appear in "Tumbling, twisting, and winding galaxies: Pattern speeds along the Hubble sequence", E. M. Corsini and V. P. Debattista (eds.), Memorie della Societa` Astronomica Italian

Lagrangian formulation for noncommutative nonlinear systems

In this work we use the well known formalism developed by Faddeev and Jackiw to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme and O(3) nonlinear sigma models. The final result is the Lagrangian formulations for the noncommutative versions of both models. The possibility of obtaining different noncommutative versions for these nonlinear systems is demonstrated.Comment: 8 pages. Revex 4.

Embrapa e as pesquisas de apoio à produção de ovos.

Projeto: 11.11.11.111