The Q2Q^2 dependence of the measured asymmetry A1A_1: the test of the Bjorken sum rule

We analyse the proton and deutron data on spin dependent asymmetry $A_1(x,Q^2)$ supposing the DIS structure functions $g_1(x,Q^2)$ and $F_3(x,Q^2)$ have the similar $Q^2$-dependence. As a result, we have obtained that $\Gamma_1^p - \Gamma_1^n = 0.190 \pm 0.038$ at $Q^2= 10 GeV^2$ and $\Gamma_1^p - \Gamma_1^n = 0.165 \pm 0.026$ at $Q^2= 3 GeV^2$, what is in the best agreement with the Bjorken sum rule predictions.Comment: LaTeX, 5 pages, no figures, to be published in JETP Letter

Characterization of symbolic play in deaf children: case and control studies

BACKGROUND: children with hearing loss do not acquire language at the same time nor at the same rate of normal hearing children because the learning process of oral language is essentially auditory. Child development consists in gradually acquiring motor and psychocognitive abilities. Entering the symbolic world is decisive for the child to reach higher levels of linguistic complexity. AIM: to correlate symbolic play and aspects of child development in deaf children and in hearing children. METHOD: participants of this study were 32 children, of both genders, with ages between 2 and 6 years, age matched. All participants were submitted to the Evaluation of Symbolic Maturation and to the Denver Developmental Screening Test II. Sixteen participants presented moderate to profound sensory-neural hearing loss and composed the research group (RG); the remaining 16 children had normal hearing and composed the control group (CG). RESULTS: symbolism was observed in the play of 81.25% of RG and in 87.5% of CG. In the Denver Developmental Screening Test II, 100% of the RG was classified as being at risk. As for the CG, 94% of the children were classified as normal and the remaining 6% as being at risk (p<0.001). CONCLUSION: a similar performance was observed between the groups for symbolic play. However, in a qualitative analysis, the RG presented less complex symbolic play than the CG. It was observed that the RG presented a performance in the symbolic play compatible to its performance in aspects of personal-social, refined motor and gross motor control in the Denver Developmental Screening Test II.TEMA: crianças deficientes auditivas não adquirem linguagem no mesmo período e velocidade de uma criança normo-ouvinte, pois o aprendizado da linguagem oral é um evento essencialmente auditivo. O desenvolvimento da criança consiste na aquisição progressiva de habilidades motoras e psicocognitivas, e a entrada no mundo simbólico é fator preponderante para que a criança possa atingir os níveis de maior complexidade no domínio da linguagem. OBJETIVO: relacionar o jogo simbólico e aspectos do desenvolvimento infantil em crianças deficientes auditivas com seus pares ouvintes. MÉTODO: 32 crianças, de ambos os sexos, de 2 a 6 anos de idade, pareadas por idade, foram submetidas à Avaliação da Maturidade Simbólica e ao Teste de Triagem do Desenvolvimento de Denver II, sendo 16 deficientes auditivas neurossensorial de grau moderado a profundo (grupo pesquisa - GP) e 16 normo-ouvintes (grupo controle - GC). RESULTADOS: observou-se simbolismo na brincadeira de 81,25% do GP, enquanto que no GC isto ocorreu em 87,5%. No Teste de Denver II 100% do GP foi classificado como risco, e o GC apresentou 94% de crianças normais e 6% de risco (p < 0,001). CONCLUSÃO: observou-se desempenho semelhante nos dois grupos quanto ao jogo simbólico. Entretanto, numa análise qualitativa, o GP apresentou brincadeiras menos complexas que o GC. Observou-se que o GP apresentou desempenho no jogo simbólico compatível ao seu desempenho nos aspectos pessoal-social, motor fino-adaptativo e motor grosseiro do Teste de Denver II.Universidade de São PauloCentro de Estudos da VozUniversidade Federal do Rio Grande do SulUNIFESP-EPM Departamento de Fonoaudiologia da Disciplina de Distúrbios da Comunicação HumanaUNIFESP, EPM, Depto. de Fonoaudiologia da Disciplina de Distúrbios da Comunicação HumanaSciEL

Effet de la nature des ions alcalins et alcalino-terreux sur la structure d'un verre riche en terre

Dans le cadre d'une étude structurale d'un verre de confinement de déchets nucléaires de type aluminoborosilicate et riche en terres rares, l'influence de la nature des ions alcalins ou alcalino-terreux est analysée. Pour cela deux séries de verres ont été élaborées dans lesquelles l'ion Na+ (respectivement l'ion Ca2+) présent dans la composition de référence, est totalement substitué par un autre ion alcalin Li+, K+, Rb+ ou Cs+ (respectivement un autre ion alcalino-terreux Mg2+, Sr2+ ou Ba2+). Ces verres, analysés par spectroscopie d'absorption optique, Raman et RMN 27Al et 11B, ont permis de montrer le fort impact de la nature de l'ion modificateur aussi bien sur la structure du réseau vitreux ( variation du rapport BO3/BO4 et variations locales du degré de polymérisation) que de l'environnement local de la terre rare (diminution du degré de covalence de la liaison Nd-O avec l'augmentation de la force de champ de l'ion modificateur)

Determination of the Strange Quark Content of the Nucleon from a Next-to-Leading-Order QCD Analysis of Neutrino Charm Production

We present the first next-to-leading-order QCD analysis of neutrino charm production, using a sample of 6090 $\nu_\mu$- and $\bar\nu_\mu$-induced opposite-sign dimuon events observed in the CCFR detector at the Fermilab Tevatron. We find that the nucleon strange quark content is suppressed with respect to the non-strange sea quarks by a factor $\kappa = 0.477 \: ^{+\:0.063}_{-\:0.053}$, where the error includes statistical, systematic and QCD scale uncertainties. In contrast to previous leading order analyses, we find that the strange sea $x$-dependence is similar to that of the non-strange sea, and that the measured charm quark mass, $m_c = 1.70 \pm 0.19 \:{\rm GeV/c}^2$, is larger and consistent with that determined in other processes. Further analysis finds that the difference in $x$-distributions between $xs(x)$ and $x\bar s(x)$ is small. A measurement of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cd}|=0.232 ^{+\:0.018}_{-\:0.020}$ is also presented. uufile containing compressed postscript files of five Figures is appended at the end of the LaTeX source.Comment: Nevis R#150

A measurement of alphas(Q2)alpha_s(Q^2) from the Gross-Llewellyn Smith Sum Rule

We extract a set of values for the Gross-Llewellyn Smith sum rule at different values of 4-momentum transfer squared ($Q^{2}$), by combining revised CCFR neutrino data with data from other neutrino deep-inelastic scattering experiments for $1 < Q^2 < 15 GeV^2/c^2$. A comparison with the order $\alpha^{3}_{s}$ theoretical predictions yields a determination of $\alpha_{s}$ at the scale of the Z-boson mass of $0.114 \pm^{.009}_{.012}$. This measurement provides a new and useful test of perturbative QCD at low $Q^2$, because of the low uncertainties in the higher order calculations.Comment: 4 pages, 4 figure

Por uma nova cultura da água no ensino básico

A presente comunicação centra-se na apresentação à comunidade científica de um Projecto de investigação em Educação que tem como finalidade produzir contributos para o Ensino Básico, no âmbito do que se designa como uma Nova Cultura da Água. Com esta iniciativa pretendemos não só alertar para a pertinência e importância de estudos em ordem a uma temática cada vez mais emergente, mas também recolher contributos significativos de uma comunidade mais alargada. O referido projecto centra-se pois no bem Água. Começará por procurar conhecer melhor como ele é evocado e tratado no Ensino Básico. Destina-se a aprofundar e promover teorias, conhecimentos, competências, valores, atitudes e práticas que potenciem o bom uso e a protecção daquele bem, e de um modo mais geral uma alteração de posturas culturais e mesmo civilizacionais. Fá-lo-á segundo perspectivas científicas, pedagógicas, didácticas e sociais em parte já construídas e em parte a construir, e que justificadamente se considerem adequadas. O Projecto assume estar à partida marcado por saberes, perspectivas, ideais, dilemas e objectivos dos elementos da equipa do Projecto e por outras visões que, globalmente e de um modo aproximativo, aglomeramos sob a designação Nova Cultura da Água. Simultaneamente, assume que pretende contribuir para que tal Nova Cultura da Água seja mais bem compreendida e especificada, e em particular para que ela seja mais enriquecida com contributos portugueses. O âmbito central de intervenção do Projecto é o Ensino Básico, mas desde logo isso implica a sua intersecção com a Formação (Inicial e Contínua) de Professores, e portanto com o Ensino Superior. Além disso, pela natureza do tema, do bem, em estudo, o Projecto intersecta-se também com os mundos das Ciências e das Tecnologias. Intersecta-se também com a Sociedade em geral, e designadamente com a formação para a cidadania de cidadão portugueses que são também cidadãos da Península Ibérica, da Europa e do Mundo. O Projecto terá pois múltiplas incidências e mesmo, previsivelmente, contributos de vários tipos e âmbitos, designadamente a nível de divulgação científica e a um nível pedagógico geral. Mas é essencialmente um Projecto do âmbito da Didáctica. Tem a sua focagem na Escola, portanto em ambientes de ensino e aprendizagem formais, e incide sobre meios e métodos relacionados com ambientes de aula (em sentido lato)

Prediction of peptide and protein propensity for amyloid formation

Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔGº values for peptides extrapolated in 0 M urea). Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html) capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation

A High Statistics Search for Electron-Neutrino --> Tau-Neutrino Oscillations

We present new limits on nu_e to nu_tau and nu_e to nu_sterile oscillations by searching for electron neutrino dissappearance in the high-energy wide-band CCFR neutrino beam. Sensitivity to nu_tau appearance comes from tau decay modes in which a large fraction of the energy deposited is electromagnetic. The beam is composed primarily of muon neutrinos but this analysis uses the 2.3% electron neutrino component of the beam. Electron neutrino energies range from 30 to 600 GeV and flight lengths vary from 0.9 to 1.4 km. This limit improves the sensitivity of existing limits and obtains a lowest 90% confidence upper limit in sin**2(2*alpha) of 9.9 x 10**(-2) at delta-m**2 of 125 eV**2.Comment: submitted to Phys. Rev. D. Rapid Com

Experimental Evidence for Simple Relations between Unpolarized and Polarized Parton Distributions

The Pauli exclusion principle is advocated for constructing the proton and neutron deep inelastic structure functions in terms of Fermi-Dirac distributions that we parametrize with very few parameters. It allows a fair description of the recent NMC data on $F^p_2(x,Q^2)$ and $F^n_2(x,Q^2)$ at $Q^2=4 GeV^2$, as well as the CCFR neutrino data at $Q^2=3$ and $5 GeV^2$. We also make some reasonable and simple assumptions to relate unpolarized and polarized quark parton distributions and we obtain, with no additional free parameters, the spin dependent structure functions $xg^p_1(x,Q^2)$ and $xg^n_1(x,Q^2)$. Using the correct $Q^2$ evolution, we have checked that they are in excellent agreement with the very recent SMC proton data at $Q^2=10 GeV^2$ and the SLAC neutron data at $Q^2=2 GeV^2$.Comment: 17 pages,CPT-94/P.3032,latex,6 fig available on cpt.univ-mrs.fr directory pub/preprints/94/fundamental-interactions /94-P.303