Recomendações para a produção de mudas de cajueiro em tubetes.

Recomendacoes para a producao de mudas de cajueiro em tubetes.bitstream/item/33816/1/Ct-068.pd

Evidence for a Very Large-Scale Fractal Structure in the Universe from Cobe Measurements

In this work, we analyse the temperature fluctuations of the cosmic microwave background radiation observed by COBE and show that the distribution can be fitted by a fractal distribution with a fractal dimension $D= 1.43 \pm 0.07$. This value is in close agreement with the fractal dimension obtained by Coleman and Pietronero (1992) and Luo and Schramm (1992) from galaxy-galaxy and cluster-cluster correlations up to $\sim 100 h^{-1} Mpc$. The fact that the observed temperature fluctuations correspond to scales much larger than $100 h^{-1} Mpc$ and are signatures of the primordial density fluctuations at the recombination layer suggests that the structure of the matter at the early universe was already fractal and thus non-homogeneous on those scales. This result may have important consequences for the theoretical framework that describes the universe.Comment: 11 pages, postscript file, 2 figures available upon request. To appear in ApJ Letter

How much time do you spend online? Understanding and improving the accuracy of self-reported measures of internet use

Given the importance of survey measures of online media use for communication research, it is crucial to assess and improve their quality, in particular because the increasingly fragmented and ubiquitous usage of internet complicates the accuracy of self-reported measures. This study contributes to the discussion regarding the accuracy of self-reported internet use by presenting relevant factors potentially affecting biases of self-reports and testing survey design strategies to improve accuracy. Combining automatic tracking data and survey data from the same participants (N = 690) confirmed low levels of accuracy and tendencies of over-reporting. The analysis revealed biases due to a range of factors associated with the intensity of (actual) internet usage, propensity to multitask, day of reference, and the usage of mobile devices. An anchoring technique could not be proved to reduce inaccuracies of reporting behavior. Several recommendations for research practice follow from these findings

Normas de produção de mudas.

As presentes normas objetivam estabelecer condicoes que devem ser obedecidas para a producao de mudas com qualidade e tecnologias aplicadas pela Embrapa Agroindustria Tropical.bitstream/CNPAT-2010/5462/1/Dc-041.pd

Desenvolvimento de um PCR multiplex para detecção simultânea de vírus e fitoplasma em mandioca (Manihot esculenta).

A mandioca (Manihot esculenta Cranz.) é de grande importância por ser considerada a base de segurança alimentar de países em desenvolvimento, sendo a principal fonte de energia na dieta das populações de países pobres. Muitos fatores abióticos (seca) e bióticos (pragas e doenças) contribuem para a baixa produtividade da cultura, dentre eles doenças que podem causar prejuízos consideráveis

Spin Transfer from a Ferromagnet into a Semiconductor through an Oxide barrier

We present results on the magnetoresistance of the system Ni/Al203/n-doped Si/Al2O3/Ni in fabricated nanostructures. The results at temperature of 14K reveal a 75% magnetoresistance that decreases in value up to approximately 30K where the effect disappears. We observe minimum resistance in the antiparallel configurations of the source and drain of Ni. As a possibility, it seems to indicate the existence of a magnetic state at the Si/oxide interface. The average spin diffusion length obtained is of 650 nm approximately. Results are compared to the window of resistances that seems to exist between the tunnel barrier resistance and two threshold resistances but the spin transfer seems to work in the range and outside the two thresholds