Mass-splittings of doubly heavy baryons in QCD

We consider (for the first time) the ratios of doubly heavy baryon masses (spin 3/2 over spin 1/2 and SU(3) mass-splittings) using double ratios of sum rules (DRSR), which are more accurate than the usual simple ratios often used in the literature for getting the hadron masses. In general, our results agree and compete in precision with potential model predictions. In our approach, the alpha(s) corrections induced by the anomalous dimensions of the correlators are the main sources of the Xi(QQ)*-Xi(QQ) mass-splittings, which seem to indicate a 1/M(Q) behaviour and can only allow the electromagnetic decay Xi(QQ)* -> Xi(QQ) + gamma but not to Xi(QQ) + pi. Our results also show that the SU(3) mass-splittings are (almost) independent of the spin of the baryons and behave approximately like 1/M(Q), which could be understood from the QCD expressions of the corresponding two-point correlator. Our results can improved by including radiative corrections to the SU(3) breaking terms and can be tested, in the near future, at Tevatron and LHCb. (C) 2010 Published by Elsevier B.V.

A percepção do professor acerca do seu trabalho com crianças portadoras de autismo e síndrome de down : um estudo comparativo

The aim of the present study was to investigate the teacher’s perception about working both with individuals with autism and with Down’s syndrome. A semi-structured interview was performed with 10 teachers, in two special schools, in the interior of the state of Rio Grande do Sul. Each one of these interviews was compound of a range of questions, dealing with topics such as teacher’s identification, etiologic notions about the syndrome, intellectual development and clinical characteristics of the children, ways of educational intervention and finally the difficulties and feelings of the teachers concerning their work in this area and also their educational strategies. The analysis of the obtained material revealed that there are similarities and differences in the way in which the teachers perceive their students with the Down’s syndrome or Autism. One fundamental aspect which was identified related to the circumstances that led the teacher to work with these children, which were not always founded on choice. One of the concerns, which mostly differentiated the teacher’s discourse, was in relation to pleasure when working with these children. This appears more clearly regarding the students with Down’s syndrome, indicating a feeling of well-being and satisfaction of the teacher, due to the social reciprocity and communication in the relationship with the children. On the other hand, stereotyped ideas; worries with behaviors that are not specific to the anxiety and lack of self-confidence were aspects which characterized the teacher’s perception about autism. This picture might have influenced their management strategies. For example, in order to alleviate their conflicts and anxieties the teachers used strategies to maintain the students systematically busy to attempt to “control” the autism. However, the practice of “sheltering” by means of flexible work and encouragement of the autonomy based on the exercise of choice were also identified in some of the teachers. Another aspect that deserves attention is in the relation to the beliefs about the etiology of autism, specifically those concerning the mother-child bond. A simplistic view of this issue was identified, which was understood as a direct relationship of “cause and effect” rather as a reciprocal process, where each element of the dyad contributes to its quality. Finally, the results of this paper point to a complexity but not impossibility of the educational process of the so-called “special” student. However, attention should be paid to the need of founding the educational practice on knowledge, thus avoiding the emergency of distorted ideas and subsequently practices incoherent with the individual’s development.

Configuração da área de estudos no currículo do ensino de 1. grau

Este estudo focaliza o modelo de currículo adotado para o ensino de 1º Grau, pela Lei 5.692/71, com destaque à configuração das áreas de estudo, componentes curriculares das séries finais. Tem por objetivo esclarecer a necessidade de revisão do conceito de áreas de estudo, visto que pela análise efetuada o mesmo parece ter sido usado inadequadamente. Procurou-se, a partir da análise das técnicas de elaboração de currículos abordadas na literatura consultada, evidenciar a falha do modelo de currículo para o ensino de 1º Grau. Concluiu-se que, em decorrência da inadequação do conceito, o currículo apresenta falhas em sua composição, visto que há justaposição dos enfoques empregados para justificar a organização das matérias no currículo e a organização das experiências de aprendizagem. O problema da conceituação imprecisa pode ter implicações negativas para a organização do ensino das áreas de estudo e comprometer os objetivos educacionais. A autora propõe a realização de uma pesquisa junto aos professores em serviço para investigação de como está sendo interpretado o conceito de áreas de estudo.

Modeling of average growth curve in Santa Ines sheep using random regression models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

VCO Banda Larga Integrado para Receptor a Cinco Portas

This work presents an wideband ring VCO for cognitive radio five-port based receivers. A three-stage differential topology using transmission gate was adopted in order to maintain wide and linear tuning range and a low phase-noise. Monte-Carlo analysis were performed for phase-shift response of individual stages, which is an important figure of merit in five-port works. It was observed a fairly linear correlation between control voltage and oscillation frequency in the range between 200 MHz and 1800 MHz. The VCO was preliminarily designed for IBM 130nm CMOS technology

eta ->gamma gamma decay width via the Primakoff cross section

Incoherent eta photoproduction in nuclei is evaluated at forward angles within 4 to 9 GeV using a multiple scattering Monte Carlo cascade calculation with full eta-nucleus final-state interactions. The Primakoff, nuclear coherent and nuclear incoherent components of the cross sections fit remarkably well previous measurements for Be and Cu from Cornell, suggesting a destructive interference between the Coulomb and nuclear coherent amplitudes for Cu. The inelastic background of the data is consistently attributed to the nuclear incoherent part, which is clearly not isotropic as previously considered in Cornell's analysis. The respective Primakoff cross sections from Be and Cu give Gamma(eta ->gamma gamma)=0.476(62) keV, where the quoted error is only statistical. This result is consistent with the Particle Data Group average of 0.510(26) keV and in sharp contrast (similar to 50%) with the value of 0.324(46) keV obtained at Cornell.

Topological charge screening and pseudoscalar glueballs

Topological charge screening in the QCD vacuum is found to provide crucial nonperturbative contributions to the short-distance expansion of the pseudoscalar (0-+) glueball correlator. The screening contributions enter the Wilson coefficients and are an indispensable complement to the direct instanton contributions. They restore consistency with the anomalous axial Ward identity and remedy several flaws in the 0-+ glueball sum rules caused by direct instantons in the absence of screening (lack of resonance signals, violation of the positivity bound and of the underlying low-energy theorem). The impact of the finite width of the instanton size distribution and the (gauge-invariant) renormalization of the instanton contributions are also discussed. New predictions for the 0-+ glueball mass and decay constant are presented.

Study of W boson production in PbPb and pp collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of isolated photon production in pp and PbPb collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of Z Boson Production in PbPb Collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Study of high-p(T) charged particle suppression in PbPb compared to pp collisions at root s(NN)=2.76 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Perda de produtividade potencial da cultura do sorgo no Estado de São Paulo

O objetivo deste trabalho foi estimar a perda de produtividade potencial do sorgo em 36 épocas de semeadura, para quatro localidades do Estado de São Paulo: Manduri, Piracicaba, Ribeirão Preto e Ilha Solteira. As estimativas basearam-se nas chances de atendimento das exigências hídricas da cultura, utilizando-se do método de Doorenbos e Kassam/FAO, para estimativa da produtividade potencial e real. Foi necessário acrescentar um fator de correção com base na temperatura do ar para a obtenção de estimativas coerentes com o modelo. Utilizaram-se séries de dados climatológicos entre 10 e 40 anos. Foi possível identificar épocas de semeadura com menores riscos para o cultivo do sorgo e as chances de perda para cada época do ano. em Manduri, Piracicaba, Ilha Solteira e Ribeirão Preto, os riscos de quebra de produção foram menores nas semeaduras entre 15-10 e 15-11, com quebras inferiores a 5%. em todas as localidades, foram observadas perdas inferiores a 5% para semeaduras realizadas em fevereiro.

Path dependence of the quark nonlocal condensate within the instanton model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

ON NUCLEON-NUCLEUS SCATTERING AND THE RELATIVISTIC EIKONAL APPROXIMATION

We introduce a generalization of the relativistic eikonal amplitude originally developed to describe elastic scattering between structureless particles. The coherent and incoherent proton-nucleus scattering processes are analysed and closed-form expressions for elastic and inelastic amplitudes are derived. In particular, for the incoherent case, an energy-conserving version of Glauber's theory is obtained.

Solitons in Bose-Einstein condensates trapped in a double-well potential

We investigate, analytically and numerically, families of bright solitons in a system of two linearly coupled nonlinear Schrodinger/Gross-Pitaevskii equations, describing two Bose-Einstein condensates trapped in an asymmetric double-well potential, in particular, when the scattering lengths in the condensates have arbitrary magnitudes and opposite signs. The solitons are found to exist everywhere where they are permitted by the dispersion law. Using the Vakhitov-Kolokolov criterion and numerical methods, we show that, except for small regions in the parameter space, the solitons are stable to small perturbations. Some of them feature self-trapping of almost all the atoms in the condensate with no atomic interaction or weak repulsion is coupled to the self-attractive condensate. An unusual bifurcation is found, when the soliton bifurcates from the zero solution with vanishing amplitude and width simultaneously diverging but at a finite number of atoms in the soliton. By means of numerical simulations, it is found that, depending on values of the parameters and the initial perturbation, unstable solitons either give rise to breathers or completely break down into incoherent waves (radiation). A version of the model with the self-attraction in both components, which applies to the description of dual-core fibers in nonlinear optics, is considered too, and new results are obtained for this much studied system. (C) 2003 Elsevier B.V. All rights reserved.