Atividade antioxidante e compostos fenólicos de cinco acessos de pimentas Capsicum chinense.

Pimentas além de serem popularmente utilizadas como condimentos, representam uma fonte significativa de compostos antioxidantes. A espécie de pimentas Capsicum chinense, originária do Brasil apresenta mais de 40 variedades, sendo que muitas ainda são desconhecidas quanto as suas potencialidades. Neste trabalho foram caracterizados quanto à atividade antioxidante e ao teor de compostos fenólicos, cinco genótipos de pimenta C. chinense do Banco Ativo de Germoplasma da Embrapa Amazônia Oriental, visando identificar as variedades promissoras para serem utilizadas em futuros programas de melhoramento genético. A atividade antioxidante foi determinada através dos ensaios de DPPH e ABTS e os compostos fenólicos através do reagente de Follin Ciocalteau. Em relação ao teor de compostos fenólicos a variedade (PCL-02) destacou-se das demais com 12710 mgEAG/100g de pimenta. Houve diferença significativa ao nível de 5% nos resultados das três análises para as cinco variedades de pimenta analisada, demonstrando que a intensidade desta ação antioxidante é diferenciada em cada uma das variedades

Semiclassical Evolution of Dissipative Markovian Systems

A semiclassical approximation for an evolving density operator, driven by a "closed" hamiltonian operator and "open" markovian Lindblad operators, is obtained. The theory is based on the chord function, i.e. the Fourier transform of the Wigner function. It reduces to an exact solution of the Lindblad master equation if the hamiltonian operator is a quadratic function and the Lindblad operators are linear functions of positions and momenta. Initially, the semiclassical formulae for the case of hermitian Lindblad operators are reinterpreted in terms of a (real) double phase space, generated by an appropriate classical double Hamiltonian. An extra "open" term is added to the double Hamiltonian by the non-hermitian part of the Lindblad operators in the general case of dissipative markovian evolution. The particular case of generic hamiltonian operators, but linear dissipative Lindblad operators, is studied in more detail. A Liouville-type equivariance still holds for the corresponding classical evolution in double phase, but the centre subspace, which supports the Wigner function, is compressed, along with expansion of its conjugate subspace, which supports the chord function. Decoherence narrows the relevant region of double phase space to the neighborhood of a caustic for both the Wigner function and the chord function. This difficulty is avoided by a propagator in a mixed representation, so that a further "small-chord" approximation leads to a simple generalization of the quadratic theory for evolving Wigner functions.Comment: 33 pages - accepted to J. Phys.

Universal 1/f Noise from Dissipative SOC Models

We introduce a model able to reproduce the main features of 1/f noise: hyper-universality (the power-law exponents are independent on the dimension of the system; we show here results in d=1,2) and apparent lack of a low-frequency cutoff in the power spectrum. Essential ingredients of this model are an activation-deactivation process and dissipation.Comment: 3 Latex pages, 2 eps Figure

Thermal and ultraviolet-visible light stability kinetics of co-nanoencapsulated carotenoids.

Made available in DSpace on 2017-11-07T23:29:52Z (GMT). No. of bitstreams: 1 CantillanoArtigo02Medelin.pdf: 973610 bytes, checksum: ca860a5fd3ef76c8c4134555c1d6f7ca (MD5) Previous issue date: 2017-11-07bitstream/item/166204/1/Cantillano-Artigo-02-Medelin.pd

Comparative study of neutron and nuclear matter with simplified Argonne nucleon-nucleon potentials

We present calculations of the energy per particle of pure neutron and symmetric nuclear matter with simplified Argonne nucleon-nucleon potentials for different many-body theories. We compare critically the Brueckner-Hartree-Fock results to other formalisms, such as the Brueckner-Bethe-Goldstone expansion up to third order, Self-Consistent Green's Functions, Auxiliary Field Diffusion Monte Carlo, and Fermi Hyper Netted Chain. We evaluate the importance of spin-orbit and tensor correlations in the equation of state and find these to be important in a wide range of densities.Comment: 13 pages, 5 figures, 3 table

Self-organized criticality in deterministic systems with disorder

Using the Bak-Sneppen model of biological evolution as our paradigm, we investigate in which cases noise can be substituted with a deterministic signal without destroying Self-Organized Criticality (SOC). If the deterministic signal is chaotic the universality class is preserved; some non-universal features, such as the threshold, depend on the time correlation of the signal. We also show that, if the signal introduced is periodic, SOC is preserved but in a different universality class, as long as the spectrum of frequencies is broad enough.Comment: RevTex, 8 pages, 8 figure

A Radial Velocity Survey of the Cygnus OB2 Association

We conducted a radial velocity survey of the Cygnus OB2 Association over a 6 year (1999 - 2005) time interval to search for massive close binaries. During this time we obtained 1139 spectra on 146 OB stars to measure mean systemic radial velocities and radial velocity variations. We spectroscopically identify 73 new OB stars for the first time, the majority of which are likely to be Association members. Spectroscopic evidence is also presented for a B3Iae classification and temperature class variation (B3 - B8) on the order of 1 year for Cygnus OB2 No. 12. Calculations of the intial mass function with the current spectroscopic sample yield Gamma = -2.2 +/- 0.1. Of the 120 stars with the most reliable data, 36 are probable and 9 are possible single-lined spectroscopic binaries. We also identify 3 new and 8 candidate double-lined spectroscopic binaries. These data imply a lower limit on the massive binary fraction of 30% - 42%. The calculated velocity dispersion for Cygnus OB2 is 2.44 +/- km/s, which is typical of open clusters. No runaway OB stars were found.Comment: 56 pages, 23 figures, 5 tables, accepted for publication in the Astrophysical Journa

On the origin of the Boson peak in globular proteins

We study the Boson Peak phenomenology experimentally observed in globular proteins by means of elastic network models. These models are suitable for an analytic treatment in the framework of Euclidean Random Matrix theory, whose predictions can be numerically tested on real proteins structures. We find that the emergence of the Boson Peak is strictly related to an intrinsic mechanical instability of the protein, in close similarity to what is thought to happen in glasses. The biological implications of this conclusion are also discussed by focusing on a representative case study.Comment: Proceedings of the X International Workshop on Disordered Systems, Molveno (2006

Self-Organized Criticality Driven by Deterministic Rules

We have investigated the essential ingredients allowing a system to show Self Organized Criticality (SOC) in its collective behavior. Using the Bak-Sneppen model of biological evolution as our paradigm, we show that the random microscopic rules of update can be effectively substituted with a chaotic map without changing the universality class. Using periodic maps SOC is preserved, but in a different universality class, as long as the spectrum of frequencies is broad enough.Comment: 4 pages, RevTex (tar.gz), 4 eps-figures include