Pseudoscalars Mesons in Hot, Dense Matter

Phase transitions in hot and dense matter and the in--medium behavior of pseudoscalar mesons ($\pi^{\pm}, \pi^0, K^{\pm}, K^0 ,\bar K^0,\eta {and} \eta'$) are investigated, in the framework of the three flavor Nambu--Jona-Lasinio model, including the 't Hooft interaction, which breaks the $U_A(1)$ symmetry. Three different scenarios are considered: zero density and finite temperature, zero temperature and finite density in quark matter with different degrees of strangeness, and finite temperature and density. At T=0, the role of strange valence quarks in the medium is discussed, in connection with the phase transition and the mesonic behavior. It is found that the appearance of strange quarks, above certain densities, leads to meaningful changes in different observables, especially in matter with \beta$--equilibrium. The behavior of mesons in the$T-\rho$ plane is analyzed in connection with possible signatures of restoration of symmetries.Comment: 33 pages, 12 figures, PRC versio

Adubação nitrogenada para pastagens do gênero Brachiaria em solos do Cerrado.

Introdução; Gênero Brachiaria; Matéria orgânica do solo e sua relação com a disponibilidade de N; Adições de nitrogênio ao sistema solo-pastagem; Importância da adubação nitrogenada em pastagens; Concentrações de nitrogênio e estimativa do teor de clorofila; Dinâmica do nitrogênio em pastagens; Perdas de nitrogênio do sistema solo-pastagem; Eficiência e recuperação do nitrogênio; Eficiência do nitrogênio na produção animal; Recomendação de adubação nitrogenada; Recomendação de adubação nitrogenada para o gênero Brachiaria de acordo com a fertilidade do solo; Recomendação de adubação nitrogenada para o gênero Brachiaria de acordo com o sistema de pastejo; Formas de aplicação de nitrogênio para pastagens; Considerações finais.bitstream/CNPAF/25514/1/doc_192.pd

Effective restoration of chiral and axial symmetries at finite temperature and density

The effective restoration of chiral and axial symmetries is investigated within the framework of the SU(3) Nambu-Jona-Lasinio model. The topological susceptibility, modeled from lattice data at finite temperature, is used to extract the temperature dependence of the coupling strength of the anomaly. The study of the scalar and pseudoscalar mixing angles is performed in order to discuss the evolution of the flavor combinations of $q \bar q$ pairs and its consequences for the degeneracy of chiral partners. A similar study at zero temperature and finite density is also realized.Comment: 5 pages, 1 figure. Talk given at Strange Quark Matter 2004, Cape Town, South Africa, 15-20 September, 200

Universal relaxation function in nonextensive systems

We have derived the dipolar relaxation function for a cluster model whose volume distribution was obtained from the generalized maximum Tsallis nonextensive entropy principle. The power law exponents of the relaxation function are simply related to a global fractal parameter $\alpha$ and for large time to the entropy nonextensivity parameter $q$. For intermediate times the relaxation follows a stretched exponential behavior. The asymptotic power law behaviors both in the time and the frequency domains coincide with those of the Weron generalized dielectric function derived from an extension of the Levy central limit theorem. They are in full agreement with the Jonscher universality principle. Moreover our model gives a physical interpretation of the mathematical parameters of the Weron stochastic theory and opens new paths to understand the ubiquity of self-similarity and power laws in the relaxation of large classes of materials in terms of their fractal and nonextensive properties.Comment: Two figures. Submitted for publicatio

First-order transitions and triple point on a random p-spin interaction model

The effects of competing quadrupolar- and spin-glass orderings are investigated on a spin-1 Ising model with infinite-range random $p$-spin interactions. The model is studied through the replica approach and a phase diagram is obtained in the limit $p\to\infty$. The phase diagram, obtained within replica-symmetry breaking, exhibits a very unusual feature in magnetic models: three first-order transition lines meeting at a commom triple point, where all phases of the model coexist.Comment: 9 pages, 2 ps figures include

Avaliação econômica da produção de nim para o uso no controle de Spodoptera frugiperda no milho.

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Some doubts on the validity of the foreground Galactic contribution subtraction from microwave anisotropies

The Galactic foreground contamination in CMBR anisotropies, especially from the dust component, is not easily separable from the cosmological or extragalactic component. In this paper, some doubts will be raised concerning the validity of the methods used to date to remove Galactic dust emission in order to show that none of them achieves its goal. First, I review the recent bibliography on the topic and discuss critically the methods of foreground subtraction: the cross-correlation with templates, analysis assuming the spectral shape of the Galactic components, the "maximum entropy method", "internal linear combination", and "wavelet-based high resolution fitting of internal templates". Second, I analyse the galactic latitude dependence from WMAP data. The frequency dependence is discussed with the data in the available literature. The result is that all methods of subtracting the Galactic contamination are inaccurate. The galactic latitude dependence analysis or the frequency dependence of the anisotropies in the range 50-250 GHz put a constraint on the maximum Galactic contribution in the power spectrum to be less than a ~10% (68% C. L.) for a ~1 degree scale, and possibly higher for larger scales. The origin of most of the signal in the CMBR anisotropies is not Galactic. In any case, the subtraction of the Galaxy is not accurate enough to allow a "precision Cosmology"; other sources of contamination (extragalactic, solar system) are also present.Comment: 24 pages, 1 figure, accepted to be published in J. Astrophys. Ast

New evidence for lack of CMB power on large scales

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum is derived. The amplitudes of the low multipoles measured from the preliminary Planck power spectrum are significantly lower than that reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.Comment: 9 pages, 3 figure

Avaliação do óleo de Copaifera reticulata Ducke na inibição do crescimento micelial in vitro de fitopatógenos.

Entre as inúmeras espécies vegetais da flora brasileira com ação medicinal e que apresentam substâncias químicas biologicamente ativas, cita-se o gênero Copaifera, compreendendo diversas espécies produtoras de um óleo-resina extraído do tronco das árvores de grande porte, que podem atingir até 40 m de altura. ). Dentre as inúmeras espécies que compõem o gênero Copaifera, está a Copaifera reticulata Ducke, encontrada principalmente na Amazônia e na região nordeste do Brasil. No que se refere à constituição química das espécies de Copaifera, observa-se em todas, a presença de diterpenos como o ácido copálico e de sesquiterpenos como beta-bisaboleno e beta-cariofileno, efetivos contra fungos. o objetivo deste trabalho foi avaliar a atividade do óleo-resina de C. reticulata Ducke em diferentes concentrações no crescimento micelial in vitro de fitopatógenos, dos gêneros Phomopsis, Colletotrichum e Phytophthora. O experimento foi conduzido no Laboratório de Fitopatologia da Embrapa Amazônia Oriental. As amostras de óleo de copaíba utilizadas nos testes foram procedentes da Floresta Naciona l do Tapajós - FLONA, no quilômetro 67, localizada no município de Belterra, Pará. Para esta análise foram utilizados óleos provenientes de coleta realizada no verão, em outubro de 2008. As espécies fúngicas utilizadas foram: Phomopsis sp., Colletotrichum gloeosporioides e Phytophthora sp., todas obtidas da micoteca do Laboratório de Fitopatologia da Embrapa Amazônia Oriental. Os resultados mostraram que todas as concentrações utilizadas no controle da inibição micelial do fitopatógeno Phytophthora sp. mostraram-se eficientes em relação à testemunha, sendo a concentração de 750 ?L a de maior poder inibitório. O fitopatógeno C. gloeosporioides foi inibido eficientemente em todas as concentrações. Já para o fungo Phomopsis sp. as concentrações utilizadas apresentaram eficiência, porém inferiores se comparadas com os dois outros fungos avaliado