Anisotropic renormalized fluctuations in the microwave resistivity in YBCO

We discuss the excess conductivity above Tc due to renormalized order-parameter fluctuations in YBCO at microwave frequencies. We calculate the effects of the uniaxial anisotropy on the renormalized fluctuations in the Hartree approximation, extending the isotropic theory developed by Dorsey [Phys. Rev. B 43, 7575 (1991)]. Measurements of the real part of the microwave resistivity at 24 and 48 GHz and of the dc resistivity are performed on different YBCO films. The onset of the superconducting transition and the deviation from the linear temperature behavior above Tc can be fully accounted for by the extended theory. According to the theoretical calculation here presented, a departure from gaussian toward renormalized fluctuations is observed. Very consistent values of the fundamental parameters (critical temperature, coherence lenghts, penetration depth) of the superconducting state are obtained.Comment: RevTex, 8 pages with 5 figures included, to be published in Physical Review

Gate stability of GaN-Based HEMTs with P-Type Gate

status: publishe

Adição de óleo como variável de predição da qualidade de peletes em rações de frangos de corte.

No presente trabalho foi avaliado o efeito da adição de níveis crescentes de inclusão de óleo de soja em dietas peletizadas de frangos sobre a qualidade do pelete. Os tratamentos foram compostos por cinco níveis de inclusão de óleo: T1 ?1,74%; T2 ?2,87%; T3?4,01%; T4 ?5,15%; T5 ?6,28%. Estas dietas foram submetidas à peletização em equipamento CPM, após a produção foram coletadas cinco amostras por tratamento. As amostras foram resfriadas e analisadas em relação à dureza e durabilidade do pelete e porcentagem de finos. O delineamento experimental foi inteiramente ao acaso com cinco tratamentos e cinco repetições. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo teste t -Student, ao nível de 5%. Também foram testados contrastes polinomiais e geradas as equações de regressão.A inclusão crescente de óleo na dieta impactou negativamente na qualidade do pelete, com redução da dureza e durabilidade e aumento na porcentagem de finos. Entre 1,74% e 6,28% de adição de óleo, a cada 1% de aumento no nível de óleo, observou-se a redução de 0,86% na dureza e 4,43% na durabilidade do pelete, com aumento de 3,55% na porcentagem de finos na ração. This study evaluated the effect of increasing soybean oil levels on pellet qualityin broiler diets. The treatments consisted of five oil levels:T1 ?1.74 %, T2 ?2.87 %; T3 ?4.01%, T4 ?5.15%; T5 ?6.28 %. These diets were pelletized with CPM equipment, after production five samples per treatment were collected. Samples were cooled and analyzed for hardness and durability of the pellet and the percentage of fines. The experimental design was complete ly randomized with five treatments and five replicates. Data were subjected to analysis of variance and means were compared by t-Student Test at 5% level. Polynomial contrasts were also tested and generated regression equations. I ncreasing dietary oil levels impacted negatively on the pellet quality, with hardness and durability decrease and increase in the percentage of fines. the range of 1 .74% and 6. 28 % oil inclusion , every 1% increas e of soybean oil resulted in decrease of 0.86% in pellet hardness and 4. 43% in pellet durabi lity , increasing 3. 55 % the percentage of fines

Nonlinear AC resistivity in s-wave and d-wave disordered granular superconductors

We model s-wave and d-wave disordered granular superconductors with a three-dimensional lattice of randomly distributed Josephson junctions with finite self-inductance. The nonlinear ac resistivity of these systems was calculated using Langevin dynamical equations. The current amplitude dependence of the nonlinear resistivity at the peak position is found to be a power law characterized by exponent $\alpha$. The later is not universal but depends on the self-inductance and current regimes. In the weak current regime $\alpha$ is independent of the self-inductance and equal to 0.5 or both of s- and d-wave materials. In the strong current regime this exponent depends on the screening. We find $\alpha \approx 1$ for some interval of inductance which agrees with the experimental finding for d-wave ceramic superconductors.Comment: 4 pages, 5 figures, to appear in Phys. Rev. Let

La enseñanza del fútbol sala en la formación de futuros profesionales de la Educación Física: la aproximación entre la teoría y la práctica

El trabajo describe una actividad realizada en la asignatura de fútbol sala del curso de formación de profesorado en Educación Física de la Universidade de Caxias do Sul (UCS) en Brasil. Los estudiantes impartieron clases de fútbol sala para niñas con edad entre los 11 y los 14 años en los centros de enseñanza de la ciudad de Caxias do Sul y su región. El objetivo de la actividad fue proporcionar a los futuros profesionales un mayor acercamiento a la realidad con la cual se deberán enfrentar en un futuro muy cercano, produciendo una formación más significativa y relevante. Al final del curso, después de los 18 partidos semanales previstos, más las clases para las chicas, los estudiantes respondieron un pequeño cuestionario adaptado en la escala de Likert sobre la importancia de la experiencia práctica para su formación. Los resultados determinaron que 7% de los alumnos del curso consideraron que la experiencia de enseñanza con las chicas presentó poca importancia para su formación como profesionales de Educación Física. Por otra parte 16% han considerado importante la actividad práctica. 37% dijeron que la experiencia fue bastante importante y 40% han respondido que la actividad fue de fundamental importancia. Ninguno contestó que la actividad fue nada importante. Así, concluimos que la utilización de esa metodología y experiencia didáctica ha permitido la reducción de las discrepancias entre la teoría y práctica existentes en las asignaturas de carácter práctico en los cursos de formación del profesorado

Comparison of 30 THz impulsive burst time development to microwaves, H-alpha, EUV, and GOES soft X-rays

The recent discovery of impulsive solar burst emission in the 30 THz band is raising new interpretation challenges. One event associated with a GOES M2 class flare has been observed simultaneously in microwaves, H-alpha, EUV, and soft X-ray bands. Although these new observations confirm some features found in the two prior known events, they exhibit time profile structure discrepancies between 30 THz, microwaves, and hard X-rays (as inferred from the Neupert effect). These results suggest a more complex relationship between 30 THz emission and radiation produced at other wavelength ranges. The multiple frequency emissions in the impulsive phase are likely to be produced at a common flaring site lower in the chromosphere. The 30 THz burst emission may be either part of a nonthermal radiation mechanism or due to the rapid thermal response to a beam of high-energy particles bombarding the dense solar atmosphere.Comment: accepted to Astronomy and Astrophysic

Cross-sectional associations between air pollution and chronic bronchitis: an ESCAPE meta-analysis across five cohorts

BACKGROUND: This study aimed to assess associations of outdoor air pollution on prevalence of chronic bronchitis symptoms in adults in five cohort studies (Asthma-E3N, ECRHS, NSHD, SALIA, SAPALDIA) participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) project. METHODS: Annual average particulate matter (PM10, PM2.5, PMabsorbance, PMcoarse), NO2, nitrogen oxides (NOx) and road traffic measures modelled from ESCAPE measurement campaigns 2008-2011 were assigned to home address at most recent assessments (1998-2011). Symptoms examined were chronic bronchitis (cough and phlegm for ≥3 months of the year for ≥2 years), chronic cough (with/without phlegm) and chronic phlegm (with/without cough). Cohort-specific cross-sectional multivariable logistic regression analyses were conducted using common confounder sets (age, sex, smoking, interview season, education), followed by meta-analysis. RESULTS: 15 279 and 10 537 participants respectively were included in the main NO2 and PM analyses at assessments in 1998-2011. Overall, there were no statistically significant associations with any air pollutant or traffic exposure. Sensitivity analyses including in asthmatics only, females only or using back-extrapolated NO2 and PM10 for assessments in 1985-2002 (ECRHS, NSHD, SALIA, SAPALDIA) did not alter conclusions. In never-smokers, all associations were positive, but reached statistical significance only for chronic phlegm with PMcoarse OR 1.31 (1.05 to 1.64) per 5 µg/m(3) increase and PM10 with similar effect size. Sensitivity analyses of older cohorts showed increased risk of chronic cough with PM2.5abs (black carbon) exposures. CONCLUSIONS: Results do not show consistent associations between chronic bronchitis symptoms and current traffic-related air pollution in adult European populations