Irrigated rice area estimation using remote sensing techniques: Project's proposal and preliminary results

The development of a methodology for annual estimates of irrigated rice crop in the State of Rio Grande do Sul, Brazil, using remote sensing techniques is proposed. The project involves interpretation, digital analysis, and sampling techniques of LANDSAT imagery. Results are discussed from a preliminary phase for identifying and evaluating irrigated rice crop areas in four counties of the State, for the crop year 1982/1983. This first phase involved just visual interpretation techniques of MSS/LANDSAT images

Peletização de sementes de arroz.

O objetivo deste estudo foi verificar a viabilidade da peletização de sementes de arroz, sem prejuízo do poder germinativo e vigor durante o armazenamento e proporcionar adição de zinco às sementes.bitstream/CNPAF/23580/1/comt_111.pd

Sampling system for wheat (Triticum aestivum L) area estimation using digital LANDSAT MSS data and aerial photographs

A procedure to estimate wheat (Triticum aestivum L) area using sampling technique based on aerial photographs and digital LANDSAT MSS data is developed. Aerial photographs covering 720 square km are visually analyzed. To estimate wheat area, a regression approach is applied using different sample sizes and various sampling units. As the size of sampling unit decreased, the percentage of sampled area required to obtain similar estimation performance also decreased. The lowest percentage of the area sampled for wheat estimation with relatively high precision and accuracy through regression estimation is 13.90% using 10 square km as the sampling unit. Wheat area estimation using only aerial photographs is less precise and accurate than those obtained by regression estimation

Efficiency of sulfur application on soybean in two types of Oxisols in Southern Brazil.

Modern agricultural techniques have been increasing the yield of soybean (Glycine max L.) while also causing increasing removal of sulfur (S) from the soil. Besides this, the use of concentrated fertilizers with this element and inadequate soil management, with consequent formation of organic matter with low S concentrations, has been causing frequent symptoms if deficiency in the plats. To assess the effect of S on soybean yield and to establish critical levels of S-SO42- available in the soil, two experiments were conducted over a two-year period in the Parana State, Brazil, in fields containing Typic Haplorthox and Typic Eutrorthox soils, located in the municipalities of Ponta Grossa and Londrina, respectively. The experimental design was randomized blocks with five S rates (0, 25, 50, 75, and 100 kg ha-1) and four replicates. The source used was elementary S with 98% purity. The maximum estimated yields on average for the two years were obtained with application of 49.9 and 63.0 kg ha-1 in the Typic Haplorthox and Typic Eutrorthox soils, for an overall average of 56.4 kg ha-1, with S-SO42- concentrations in the 0-20 cm depth of 16.9, 19.3 and 17.1 mg kg-1, respectively, values higher than the 10 mg kg-1 indicated as the adequate concentration for soybean plant. In turn, at the 21-40 cm depth, the S concentrations were 49.5, 74.2 and 56.4 kg ha-1. The efficiency of the fertilization diminished with increasing S rates, in both soil types, while the greatest yield efficiency was obtained in the plants grown in the Typic Haplorthox soil

Qualidade fisiológica de sementes de feijoeiro comum produzidas em várzeas tropicais com subirrigação.

O objetivo do presente trabalho foi determinar a viabilidade da produção de sementes de feijoeiro comum em várzeas tropicais, com altas temperaturas durante o ciclo da cultura, utilizando-se a subirrigação e comparar sua qualidade com a semente produzida na Embrapa Arroz e Feijão, no inverno, sob pivô central.bitstream/CNPAF/23530/1/bolpesq_14.pd

Universal reduction of pressure between charged surfaces by long-wavelength surface charge modulation

We predict theoretically that long-wavelength surface charge modulations universally reduce the pressure between the charged surfaces with counterions compared with the case of uniformly charged surfaces with the same average surface charge density. The physical origin of this effect is the fact that surface charge modulations always lead to enhanced counterion localization near the surfaces, and hence, fewer charges at the midplane. We confirm the last prediction with Monte Carlo simulations.Comment: 8 pages 1 figure, Europhys. Lett., in pres

Charged inclusion in nematic liquid crystals

We present a general theory of liquid crystals under inhomogeneous electric field in a Ginzburg-Landau scheme. The molecular orientation can be deformed by electric field when the dielectric tensor is orientation-dependent. We then investigate the influence of a charged particle on the orientation order in a nematic state. The director is aligned either along or perpendicular to the local electric field around the charge, depending on the sign of the dielectric anisotropy. The deformation becomes stronger with increasing the ratio $Ze/R$, where $Ze$ is the charge and $R$ is the radius of the particle. Numerical analysis shows the presence of defects around the particle for large $Ze/R$. They are nanometer-scale defects for microscopic ions. If the dielectric anisotropy is positive, a Saturn ring defect appears. If it is negative, a pair of point defects appear apart from the particle surface, each being connected to the surface by a disclination line segment.Comment: 12 figure

Identificação e caracterização de patógenos foliares em mudas seminais de Eucalipto benthamii.

SEMIC. Resumo bilíngue. FLORE05

Conservation Laws in Cellular Automata

If X is a discrete abelian group and B a finite set, then a cellular automaton (CA) is a continuous map F:B^X-->B^X that commutes with all X-shifts. If g is a real-valued function on B, then, for any b in B^X, we define G(b) to be the sum over all x in X of g(b_x) (if finite). We say g is `conserved' by F if G is constant under the action of F. We characterize such `conservation laws' in several ways, deriving both theoretical consequences and practical tests, and provide a method for constructing all one-dimensional CA exhibiting a given conservation law.Comment: 19 pages, LaTeX 2E with one (1) Encapsulated PostScript figure. To appear in Nonlinearity. (v2) minor changes/corrections; new references added to bibliograph