Dynamical Lorentz and CPT symmetry breaking in a 4D four-fermion model

In a 4D chiral Thirring model we analyse the possibility that radiative corrections may produce spontaneous breaking of Lorentz and CPT symmetry. By studying the effective potential, we verified that the chiral current $\bar\psi\gamma^{\mu} \gamma_5 \psi$ may assume a nonzero vacuum expectation value which triggers the Lorentz and CPT violations. Furthermore, by making fluctuations on the minimum of the potential we dynamically induce a bumblebee like model containing a Chern-Simons term.Comment: Small modifications in the text and new references added, 12 pages, 4 figures, revtex4. To appear in Phys. Rev.

Does TB stigma affect emotion recognition? A study with a Portuguese sample

TB stigma constitutes a major barrier to disease control and social distress. This study aims to understand better the inherent social processes on the perception of emotions. Thus far, the specific role of TB stigma in this respect was not tested. We hypothesize that individuals in TB treatment (vs. a control non-clinical group) would identify more negative emotions in the faces of others, specifically rejecting emotions (e.g., disgust) when preoccupied with TB stigma. Two groups of participants completed a questionnaire with 23 faces, identified the emotions portrayed in the pictures, and reported their level of Stigma Consciousness, Interpersonal-Rejection Related to Stigma, and Rejection Sensitivity. Results show that the two groups significantly differ in their perceptions of negative emotions: participants in treatment identify less disgust and more sadness, fear, and anger versus the control group. Findings are discussed concerning the literature on stigma and its consequences

Single and Double Photoionization and Photodissociation of Toluene by Soft X-rays in Circumstellar Environment

The formation of polycyclic aromatic hydrocarbons (PAHs) and their methyl derivatives occurs mainly in the dust shells of asymptotic giant branch (AGB) stars. The bands at 3.3 and 3.4 $\mu$m, observed in infrared emission spectra of several objects, are attributed C-H vibrational modes in aromatic and aliphatic structures, respectively. In general, the feature at 3.3 $\mu$m is more intense than the 3.4 $\mu$m. Photoionization and photodissociation processes of toluene, the precursor of methylated PAHs, were studied using synchrotron radiation at soft X-ray energies around the carbon K edge with time-of-flight mass spectrometry. Partial ion yields of a large number of ionic fragments were extracted from single and 2D-spectra, where electron-ion coincidences have revealed the doubly charged parent-molecule and several doubly charged fragments containing seven carbon atoms with considerable abundance. \textit{Ab initio} calculations based on density functional theory were performed to elucidate the chemical structure of these stable dicationic species. The survival of the dications subjected to hard inner shell ionization suggests that they could be observed in the interstellar medium, especially in regions where PAHs are detected. The ionization and destruction of toluene induced by X-rays were examined in the T Dra conditions, a carbon-rich AGB star. In this context, a minimum photodissociation radius and the half-life of toluene subjected to the incidence of the soft X-ray flux emitted from a companion white dwarf star were determined.Comment: 11 pages, 4 figures, accept for publication in Ap

Comportamento do sistema radicular da mangueira em Podzolico Bruno Vermelho-Amarelo Distrofico sob irrigacao por sulco na regiao do Submedio Sao Francisco.

Este trabalho foi realizado n a Fazenda Frutivale, Juazeiro-BA, num p omar de man gueir a var. T ommy Atkins com quatro anos de idad e e p lantas ap resentando 4,70m de altura. O estudo comp reendeu a ab ertura de trincheir as num dos quadrantes exp lorados pela p lanta, utilizando os métodos dos monolitos descritos p or Kelesnicov (1971). Quanto à distribuição horizontal das raízes na camad a de 0 a 30cm, constatou-se que 91,34% das raízes de absorção de água e nutrientes e 100% das raízes de sustentação estavam concentradas na d istância de 0 a 150cm em relação à p lanta, quando se consid era o esp açamento entre fileiras e 88,43 e 100%, r esp ectivamente, estavam situadas na distância de 0 a 200cm, com relação ao esp açamento entre plantas. Nas camadas de 31 a 120cm de p rofundidade, a distribuícão das r aízes de absorção de água e nutrientes ap resentaram os mesmos p adrões da camada sup erficial e nas camad as a partir de 61cm não foram en contradas raízes de sustentação. Quanto a distribuíção vertical de raízes, pôde-se verificar que as concentrações de raízes de absorção de água e nutrientes diminuem de maneira brusca a medida que o solo se aprofunda, sendo que 84,37% estavam concentradas na camad a de 0 a 60cm, em ambas às direções e que 100% das raízes de sustentação estão restritas às camadas de 0 a 60 cm

Slavnov-Taylor identities for noncommutative QED4_4

In this work we present an analysis of the one-loop Slavnov-Taylor identities in noncommutative QED$_4$. The vectorial fermion-photon and the triple photon vertex functions were studied, with the conclusion that no anomalies arise.Comment: 24 pages, revtex4, v2: typos correcte

On the radiative corrections in the Horava-Lifshitz z=2 QED

We calculate one-loop contributions to the two and three point spinor-vector functions in z=2 Horava-Lifshitz QED. This allows us to obtain the anomalous magnetic moment.Comment: 10 pages, minor correction

Valor nutritivo de palha de carnaúba tratada com uréia.

bitstream/item/131478/1/circular-33-Valor-nutritivo-da-palha-de-carnauba.pd