23,695 research outputs found

    Grão de bico e lentilha: duas novas hospedeiras de Sclerotium rolfsii no Planalto Central do Brasil.

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    Neste trabalho, relata-se, pela primeira vez, a ocorrência da murcha-de-esclerócio, causada por Sclerotium rolfsii em grão-de-bico (Cicer arietinum L.) e em lentilha (Lens culinaris Medikus) na Região do Planalto Central do Brasil.bitstream/item/85036/1/bpd-92.pd

    Rizoctoniose da batateira.

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    bitstream/item/57211/1/Cot-81.pd

    Demining in Suriname

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    Since 1992, when a peace agreement was reached in Suriname, the OAS has been instrumental in demining activities throughout the country. The efforts of the Surinamese National Army as well as those of other governments have aided the country in clearing mine-affected areas and allowing civilians to return to their homes

    Oídios do tomateiro.

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    bitstream/item/103070/1/cot-66.pd

    Scaling in the crossover from random to correlated growth

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    In systems where deposition rates are high compared to diffusion, desorption and other mechanisms that generate correlations, a crossover from random to correlated growth of surface roughness is expected at a characteristic time t_0. This crossover is analyzed in lattice models via scaling arguments, with support from simulation results presented here and in other authors works. We argue that the amplitudes of the saturation roughness and of the saturation time scale as {t_0}^{1/2} and t_0, respectively. For models with lateral aggregation, which typically are in the Kardar-Parisi-Zhang (KPZ) class, we show that t_0 ~ 1/p, where p is the probability of the correlated aggregation mechanism to take place. However, t_0 ~ 1/p^2 is obtained in solid-on-solid models with single particle deposition attempts. This group includes models in various universality classes, with numerical examples being provided in the Edwards-Wilkinson (EW), KPZ and Villain-Lai-Das Sarma (nonlinear molecular-beam epitaxy) classes. Most applications are for two-component models in which random deposition, with probability 1-p, competes with a correlated aggregation process with probability p. However, our approach can be extended to other systems with the same crossover, such as the generalized restricted solid-on-solid model with maximum height difference S, for large S. Moreover, the scaling approach applies to all dimensions. In the particular case of one-dimensional KPZ processes with this crossover, we show that t_0 ~ nu^{-1} and nu ~ lambda^{2/3}, where nu and lambda are the coefficients of the linear and nonlinear terms of the associated KPZ equations. The applicability of previous results on models in the EW and KPZ classes is discussed.Comment: 14 pages + 5 figures, minor changes, version accepted in Phys. Rev.

    Literacy: A cultural influence on functional left-right differences in the inferior parietal cortex

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    The current understanding of hemispheric interaction is limited. Functional hemispheric specialization is likely to depend on both genetic and environmental factors. In the present study we investigated the importance of one factor, literacy, for the functional lateralization in the inferior parietal cortex in two independent samples of literate and illiterate subjects. The results show that the illiterate group are consistently more right-lateralized than their literate controls. In contrast, the two groups showed a similar degree of left-right differences in early speech-related regions of the superior temporal cortex. These results provide evidence suggesting that a cultural factor, literacy, influences the functional hemispheric balance in reading and verbal working memory-related regions. In a third sample, we investigated grey and white matter with voxel-based morphometry. The results showed differences between literacy groups in white matter intensities related to the mid-body region of the corpus callosum and the inferior parietal and parietotemporal regions (literate > illiterate). There were no corresponding differences in the grey matter. This suggests that the influence of literacy on brain structure related to reading and verbal working memory is affecting large-scale brain connectivity more than grey matter per se
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