Top quark forward-backward asymmetry from the 3−3−13-3-1 model

The forward-backward asymmetry $A_{FB}$ in top quark pair production, measured at the Tevatron, is probably related to the contribution of new particles. The Tevatron result is more than a $2\sigma$ deviation from the standard model prediction and motivates the application of alternative models introducing new states. However, as the standard model predictions for the total cross section $\sigma_{tt}$ and invariant mass distribution $M_{tt}$ for this process are in good agreement with experiments, any alternative model must reproduce these predictions. These models can be placed into two categories: One introduces the s-channel exchange of new vector bosons with chiral couplings to the light quarks and to the top quark and another relies on the t-channel exchange of particles with large flavor-violating couplings in the quark sector. In this work we employ a model which introduces both s- and t-channel nonstandard contributions for the top quark pair production in proton antiproton collisions. We use the minimal version of the $SU(3)_C \otimes SU(3)_L \otimes U (1)_X$ model (3-3-1 model) that predicts the existence of a new neutral gauge boson, called $Z^\prime$. This gauge boson has both flavor-changing couplings to up and top quarks and chiral coupling to the light quarks and to the top quark. This very peculiar model coupling can correct the $A_{FB}$ for top quark pair production for two ranges of $Z^\prime$ mass while leading to cross section and invariant mass distribution quite similar to the standard model ones. This result reinforces the role of the 3-3-1 model for any new physics effect.Comment: 12 pages, 4 figures, 2 table

Correlation equalities and upper bounds for the transverse Ising model

Starting from an exact formal identity for the two-state transverse Ising model and using correlation inequalities rigorous upper bounds for the critical temperature and the critical transverse field are obtained which improve effective results.Comment: 8 pages, 1 figur

Gerando aprendizagem significativa: as metáforas na aprendizagem da contabilidade

This paper approaches the importance of metaphors like meaningful learning producing and describes the undergraduate student’s opinion about the paper of these researches in accountancy course. Support itself in the Ausubel’s Meaningful Learning Theory and in the large texts about the use of analogies and metaphors in teaching. Makes a short explanation about the metaphors like cognitive researches in learning, with prominence to its connection to meaningful learning. Show the results of the study produced with accountancy’s undergraduate students of the Centro Universitário Newton Paiva localized on Belo Horizonte city – Brazil. These results show us that the use of metaphors in accountancy classes can, in the opinion of the students, to promote the meaningful learning.Este trabalho aborda a importância das metáforas como geradoras de aprendizagem significativa e relata a opinião de alunos concluintes do curso de Ciências Contábeis sobre as contribuições de tais recursos na aprendizagem de conteúdos contábeis. Apóia-se na Teoria da Aprendizagem Significativa deAusubel e na literatura referente ao uso de analogias e metáforas no ensino. Faz uma breve explanação sobre o uso de metáforas no ensino e o seu papel como recurso cognitivo. Expõe ainda o estudo de caso realizado, por meio de questionário, com os acadêmicos dos 7o e 8o períodos do curso superior de Ciências Contábeis do Centro Universitário Newton Paiva, localizado em Belo Horizonte – Brasil. Os resultados apontam que, na opinião dos discentes, o uso de metáforas em sala de aula contribui para gerar a aprendizagem significativa dos conteúdos contábeis

BR - 5110 - Solimões: o milho de várzea do Amazonas.

BR - 5110 - Solimoes, variedade selecionada e adaptada para as condicoes de varzea no Amazonas. Sao descritas, alem das caracteristicas agronomicas da variedade, as recomendacoes tecnicas para o seu plantio em area de varzea no Amazonas.bitstream/CPAA-2009-09/2730/1/Com_Tec_9.pd

Phenolic compound profile by UPLC-MS/MS and encapsulation with chitosan of Spondias mombin L. fruit peel extract from Cerrado hotspot-Brazil

8openInternationalInternational coauthor/editorTaperebá (Spondias mombin L.) is a native species of the Brazilian Cerrado that has shown important characteristics such as a significant phenolic compound content and biological activities. The present study aimed to characterize the phenolic compound profile and antioxidant activity in taperebá peel extract, as well as microencapsulating the extract with chitosan and evaluating the stability of the microparticles. The evaluation of the profile of phenolic compounds was carried out by UPLC-MS/MS. The in vitro antioxidant activity was evaluated by DPPH and ABTS methods. The microparticles were obtained by spray drying and were submitted to a stability study under different temperatures. In general, the results showed a significant content of polyphenols and antioxidant activity. The results of UPLC-MS/MS demonstrated a significant content of polyphenols in taperebá peel, highlighting the high content of ellagic acid and quercetin compounds. There was significant retention of phenolic compounds when microencapsulated, demonstrating high retention at all evaluated temperatures. This study is the first to microencapsulate the extract of taperebá peel, in addition to identifying and quantifying some compounds in this fruitopenBrito, Giovanna Oliveira de; Reis, Bruna Cabral; Ferreira, Eduardo A; Vilela Junqueira, Nilton T; Sá-Barreto, Lívia C L; Mattivi, Fulvio; Vrhovsek, Urska; Gris, Eliana FortesBrito, G.O.D.; Reis, B.C.; Ferreira, E.A.; Vilela Junqueira, N.T.; Sá-Barreto, L.C.L.; Mattivi, F.; Vrhovsek, U.; Gris, E.F