Contribuição ao conhecimento da temperatura do solo na região de Belém.

bitstream/item/93573/1/Comunicado28.pd

Lattice Simulation of Nuclear Multifragmentation

Motivated by the decade-long debate over the issue of criticality supposedly observed in nuclear multifragmentation, we propose a dynamical lattice model to simulate the phenomenon. Its Ising Hamiltonian mimics a short range attractive interaction which competes with a thermal-like dissipative process. The results here presented, generated through an event-by-event analysis, are in agreement with both experiment and those produced by a percolative (non-dynamical) model.Comment: 8 pages, 3 figure

Hermitian symmetric polynomials and CR complexity

Properties of Hermitian forms are used to investigate several natural questions from CR Geometry. To each Hermitian symmetric polynomial we assign a Hermitian form. We study how the signature pairs of two Hermitian forms behave under the polynomial product. We show, except for three trivial cases, that every signature pair can be obtained from the product of two indefinite forms. We provide several new applications to the complexity theory of rational mappings between hyperquadrics, including a stability result about the existence of non-trivial rational mappings from a sphere to a hyperquadric with a given signature pair.Comment: 19 pages, latex, fixed typos, to appear in Journal of Geometric Analysi

Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields

Assuming that the order parameter corresponds to an equal spin triplet pairing symmetry state, we calculate the effect of phase fluctuations in quasi-one-dimensional superconductors at high magnetic fields applied along the y (b') axis. We show that phase fluctuations can destroy the theoretically predicted triplet reentrant superconducting state, and that they are responsible for melting the magnetic field induced Josephson vortex lattice above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur

Produção animal de base familiar no semi-árido sergipano.

bitstream/CPATC/19778/1/f_16_2007.pd

Zoneamento Agroclimático para a Cultura da Soja no Leste do Estado do Pará.

In order to determine reasonable planting time and zoning for soybean in the regions of Northeast and Southeast Pará, water ballance simulation and a zoning approach were conduced. Water balance was analysed by using combinations of 12 planting time, soil available water and two crop varieties. In adition, field informations related to soil texture, plant phenology and crop water consumption were also analysed. From water balance several paramaters were determined including the moisture satisfaction index (HNSI) and climatic risks. The zoning approach was based on two aspects: the climatic risks as an indicator to determine the climatic suitability classes for soybean and the geographic system analyses(GIS) for spatial analysis. The overall results show 72 zoning maps indicanting favorable planting time and suitable areas for soybean crop

Transition from damage to fragmentation in collision of solids

We investigate fracture and fragmentation of solids due to impact at low energies using a two-dimensional dynamical model of granular solids. Simulating collisions of two solid discs we show that, depending on the initial energy, the outcome of a collision process can be classified into two states: a damaged and a fragmented state with a sharp transition in between. We give numerical evidence that the transition point between the two states behaves as a critical point, and we discuss the possible mechanism of the transition.Comment: Revtex, 12 figures included. accepted by Phys. Rev.

Chuvas máximas de 24 horas em Belém, probabilidade de ocorrência e tempo de retorno.

Rainfall characteristics such as seasonality and variability and occurrence of maximum 24-hour rainfalls are of great importance for the effectiveness of rainfall for agriculture, water balance and soil erosion. In order to analyse these rainfall characteristics to Belem where in general there is no dry season, various rainfall aspects were studied including: rainfall seasonality, observed and theoretical frequency distribution and recurrence interval for 24-hour rainfalls of a 30-year period. The degree of concentration of the largest rainfall events of each year on each month and the rainfall intensities within the observed largest storm were also analysed. The mean results indicated that although in Belém where annual totals usually exceed 3000mm, there is only a probability of 3 percent that annual-maximum 24-hour rainfall at Belem will equal or exceed 136mm, and that such event would be referred to as the 30-year, 24- hour rainfal