4,040 research outputs found
Estrutura e dinĆ¢mica em uma floresta de vĆ”rzea do Rio Amazonas no Estado do AmapĆ”.
O Rio Amazonas; O braƧo norte do Rio Amazonas; A vĆ”rzea do estuĆ”rio amazĆ“nico; A floresta de vĆ”rzea do estuĆ”rio amazĆ“nico; Uso dos recursos da floresta de vĆ”rzea do estuĆ”rio; A estrutura da floresta de vĆ”rzea do estuĆ”rio; DistribuiĆ§Ć£o diamĆ©trica; A dinĆ¢mica da floresta de vĆ”rzea do estuĆ”rio; DinĆ¢mica e sucessĆ£o florestal; Ingresso e recrutamento; Crescimento; Mortalidade; DescriĆ§Ć£o da Ć”rea de estudos; Clima; Solo; Ćreas da parte externa da Foz do Rio Amazonas; Vila Progresso - Bailique; IgarapĆ© RepĆŗblica; Rio Aracu - Foz do Rio Macacoari; Ćreas da parte interna da Foz do Rio Amazonas; Furo do MazagĆ£o; Rio MutuacĆ”; Rio Maniva - Ilha do ParĆ”; AnĆ”lise da estrutura da floresta; Estrutura da floresta; ComposiĆ§Ć£o florĆstica; Densidade, dominĆ¢ncia, frequĆŖncia e valor de importĆ¢ncia; DistribuiĆ§Ć£o espacial das espĆ©cies; Diversidadde de espĆ©cies; Quociente de mistura; ImportĆ¢ncia sĆ³cio-econĆ“mica da floresta em estudo; O manejo dos aƧaizais; O manejo das espĆ©cies arbĆ³reas; O manejo das espĆ©cies oleaginosas.Tese (Doutorado em CiĆŖncias Florestais) - Universidade Federal do ParanĆ”, Curitiba
Connectivity-dependent properties of diluted sytems in a transfer-matrix description
We introduce a new approach to connectivity-dependent properties of diluted
systems, which is based on the transfer-matrix formulation of the percolation
problem. It simultaneously incorporates the connective properties reflected in
non-zero matrix elements and allows one to use standard random-matrix
multiplication techniques. Thus it is possible to investigate physical
processes on the percolation structure with the high efficiency and precision
characteristic of transfer-matrix methods, while avoiding disconnections. The
method is illustrated for two-dimensional site percolation by calculating (i)
the critical correlation length along the strip, and the finite-size
longitudinal DC conductivity: (ii) at the percolation threshold, and (iii) very
near the pure-system limit.Comment: 4 pages, no figures, RevTeX, Phys. Rev. E Rapid Communications (to be
published
GerminaĆ§Ć£o de sementes de bacabinha (Oenocarous mapora Karsten).
O presente trabalho foi conduzido no Campo Experimental de Fazendinha, com o objetivo de avaliar mĆ©todos para acelerar e uniformizar a germinaĆ§Ć£o de sementes de bacabi.bitstream/item/97468/1/CPAF-AP-2000-Sementes-bacabinha.pd
Logarithmic corrections to gap scaling in random-bond Ising strips
Numerical results for the first gap of the Lyapunov spectrum of the self-dual
random-bond Ising model on strips are analysed. It is shown that finite-width
corrections can be fitted very well by an inverse logarithmic form, predicted
to hold when the Hamiltonian contains a marginal operator.Comment: LaTeX code with Institute of Physics macros for 7 pages, plus 2
Postscript figures; to appear in Journal of Physics A (Letter to the Editor
On locations and properties of the multicritical point of Gaussian and +/-J Ising spin glasses
We use transfer-matrix and finite-size scaling methods to investigate the
location and properties of the multicritical point of two-dimensional Ising
spin glasses on square, triangular and honeycomb lattices, with both binary and
Gaussian disorder distributions. For square and triangular lattices with binary
disorder, the estimated position of the multicritical point is in numerical
agreement with recent conjectures regarding its exact location. For the
remaining four cases, our results indicate disagreement with the respective
versions of the conjecture, though by very small amounts, never exceeding 0.2%.
Our results for: (i) the correlation-length exponent governing the
ferro-paramagnetic transition; (ii) the critical domain-wall energy amplitude
; (iii) the conformal anomaly ; (iv) the finite-size susceptibility
exponent ; and (v) the set of multifractal exponents
associated to the moments of the probability distribution of spin-spin
correlation functions at the multicritical point, are consistent with
universality as regards lattice structure and disorder distribution, and in
good agreement with existing estimates.Comment: RevTeX 4, 9 pages, 2 .eps figure
Surface crossover exponent for branched polymers in two dimensions
Transfer-matrix methods on finite-width strips with free boundary conditions
are applied to lattice site animals, which provide a model for randomly
branched polymers in a good solvent. By assigning a distinct fugacity to sites
along the strip edges, critical properties at the special (adsorption) and
ordinary transitions are assessed. The crossover exponent at the adsorption
point is estimated as , consistent with recent
predictions that exactly for all space dimensionalities.Comment: 10 pages, LaTeX with Institute of Physics macros, to appear in
Journal of Physics
Cultivo de aƧaizeiros e manejo de aƧaizais para produĆ§Ć£o de frutos.
ProduĆ§Ć£o de mudas de aƧaizeiros em viveiros tradicionais; ProduĆ§Ć£o de mudas de aƧaĆ em viveiros na floresta; Cultivo de aƧaizeiro; Plantio em terra firme; Plantio em vĆ”rzea, grotas e matas de galeria; Manejo de aƧaizais; Tipos de aƧaizeiros; O suco de aƧaĆ como alimento; UtilizaĆ§Ć£o de resĆduos de aƧaĆ.bitstream/item/98195/1/CPAF-AP-2001-Cultivo-acaizeros.pd
Smoothly-varying hopping rates in driven flow with exclusion
We consider the one-dimensional totally asymmetric simple exclusion process
(TASEP) with position-dependent hopping rates. The problem is solved,in a mean
field/adiabatic approximation, for a general (smooth) form of spatial rate
variation. Numerical simulations of systems with hopping rates varying linearly
against position (constant rate gradient), for both periodic and open boundary
conditions, provide detailed confirmation of theoretical predictions,
concerning steady-state average density profiles and currents, as well as
open-system phase boundaries, to excellent numerical accuracy.Comment: RevTeX 4.1, 14 pages, 9 figures (published version
Efeito do tamanho do recipiente sobre o desenvolvimento de mudas de copaĆba (Copaifera spp.).
O trabalho objetiva estudar o efeito de diferentes tamanhos de recipientes sobre o desenvolvimento de mudas de copaĆba.bitstream/item/96287/1/CPAF-AP-2001-Efeito-Copaiba.pd
Tipos de aƧaizais do estuƔrio amazƓnico e efeitos das intervenƧƵes praticadas por extratores ribeirinhos.
Denomina-se aƧaizal o ambiente florestal onde a presenƧa do aƧaizeiro (Euterpe oleracea Mart.) Ć© visĆvel e marcante. Com o objetivo de conhecer tipos de manejo, o impacto causado pela exploraĆ§Ć£o de palmito, e orientar a instalaĆ§Ć£o de projetos de pesquisa para manejo de aƧaizais, realizou-se o presente trabalho
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