Classificação de embriões bovinos produzidos in vivo.

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The use of GIS and additional information to check soil classification maps.

The aim of this work was to check the limits of the soil classification map using GlS tools and additional information. The information from the geology map, the digital elevation model, Aster images and the detailed soil classification map was used to establish the criteria for automatic classification, using some classification attributes as local elevation, slope and pixels values in images. The new reclassified soil map was compared to the original, and sampling was performed in points in field where the maps didn't match to access the quality of results. The results showed that this method is a promising tool to obtain better quality in digital soil information and to direct sampling, but the accuracy may be limited by the resolution of the available data, and field validation is necessary

Towards absolute calibration of optical tweezers

Aiming at absolute force calibration of optical tweezers, following a critical review of proposed theoretical models, we present and test the results of MDSA (Mie-Debye-Spherical Aberration) theory, an extension of a previous (MD) model, taking account of spherical aberration at the glass/water interface. This first-principles theory is formulated entirely in terms of experimentally accessible parameters (none adjustable). Careful experimental tests of the MDSA theory, undertaken at two laboratories, with very different setups, are described. A detailed description is given of the procedures employed to measure laser beam waist, local beam power at the transparent microspheres trapped by the tweezers, microsphere radius and the trap transverse stiffness, as a function of radius and height in the (inverted microscope) sample chamber. We find generally very good agreement with MDSA theory predictions, for a wide size range, from the Rayleigh domain to large radii, including the values most often employed in practice, and at different chamber heights, both with objective overfilling and underfilling. The results asymptotically approach geometrical optics in the mean over size intervals, as they should, and this already happens for size parameters not much larger than unity. MDSA predictions for the trapping threshold, position of stiffness peak, stiffness variation with height, multiple equilibrium points and `hopping' effects among them are verified. Remaining discrepancies are ascribed to focus degradation, possibly arising from objective aberrations in the infrared, not yet included in MDSA theory.Comment: 15 pages, 20 figure

Influência da temperatura de secagem da amostra na proporção das frações granulométricas de alguns Latossolos.

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A fração glomalina e a estabilidade de agregados de diferentes Latossolos.

A Glomalina é uma glicoproteina produzida por fungos micorrizicos arbusculares que tem sido associada à formação e estabilização de agregados do solo e à dinâmica no estoque de carbono. O objetivo deste trabalho foi quantificar a fração protéica relacionada à glomalina em quatro diferentes tipos de latossolos e relacioná-la à estabilidade estrutural de agregados, medida por agitação em água. Foram extraídas as frações glomalina de agregados dos tamanhos 0,50 e 0,25 mm com e sem o extrator citrato de sódio, e em seguida estes foram agitados em um aparelho de Y oder. Foram detectadas grandes diferenças entre solos no teor absoluto da fração glomalina e na estabilidade de agregados entre as modalidades de extração, com redução da estabilidade após a extração, concluindo-se que existe efeito dessa fração na estabilidade de agregados