28,140 research outputs found
Emergentism and musicology: an alternative perspective to the understanding of dissonance.
In this paper we develop an approach to musicology within the
discussion of emergentism. First of all, we claim that some theories of
musicology could be insufficient in describing and explaining musical
phenomena when emergent properties are not taken into account. Actually,
musicology usually considers just syntactical elements, structures and
processes and puts only a little emphasis, if any, over perceptual aspects of
human hearing. On the other hand, recent research efforts are currently being
directed towards an understanding of the emergent properties of auditory
perception, especially in fields such as cognitive science. Such research leads
to other views concerning old issues in musicology and could create a fruitful
approach, filling the gap between musicology and auditory perception
Numerical simulation study of the dynamical behavior of the Niedermayer algorithm
We calculate the dynamic critical exponent for the Niedermayer algorithm
applied to the two-dimensional Ising and XY models, for various values of the
free parameter . For we regain the Metropolis algorithm and for
we regain the Wolff algorithm. For , we show that the mean
size of the clusters of (possibly) turned spins initially grows with the linear
size of the lattice, , but eventually saturates at a given lattice size
, which depends on . For , the Niedermayer
algorithm is equivalent to the Metropolis one, i.e, they have the same dynamic
exponent. For , the autocorrelation time is always greater than for
(Wolff) and, more important, it also grows faster than a power of .
Therefore, we show that the best choice of cluster algorithm is the Wolff one,
when compared to the Nierdermayer generalization. We also obtain the dynamic
behavior of the Wolff algorithm: although not conclusive, we propose a scaling
law for the dependence of the autocorrelation time on .Comment: Accepted for publication in Journal of Statistical Mechanics: Theory
and Experimen
Complete high-precision entropic sampling
Monte Carlo simulations using entropic sampling to estimate the number of
configurations of a given energy are a valuable alternative to traditional
methods. We introduce {\it tomographic} entropic sampling, a scheme which uses
multiple studies, starting from different regions of configuration space, to
yield precise estimates of the number of configurations over the {\it full
range} of energies, {\it without} dividing the latter into subsets or windows.
Applied to the Ising model on the square lattice, the method yields the
critical temperature to an accuracy of about 0.01%, and critical exponents to
1% or better. Predictions for systems sizes L=10 - 160, for the temperature of
the specific heat maximum, and of the specific heat at the critical
temperature, are in very close agreement with exact results. For the Ising
model on the simple cubic lattice the critical temperature is given to within
0.003% of the best available estimate; the exponent ratios and
are given to within about 0.4% and 1%, respectively, of the
literature values. In both two and three dimensions, results for the {\it
antiferromagnetic} critical point are fully consistent with those of the
ferromagnetic transition. Application to the lattice gas with nearest-neighbor
exclusion on the square lattice again yields the critical chemical potential
and exponent ratios and to good precision.Comment: For a version with figures go to
http://www.fisica.ufmg.br/~dickman/transfers/preprints/entsamp2.pd
Lagrangian formulation for noncommutative nonlinear systems
In this work we use the well known formalism developed by Faddeev and Jackiw
to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme
and O(3) nonlinear sigma models. The final result is the Lagrangian
formulations for the noncommutative versions of both models. The possibility of
obtaining different noncommutative versions for these nonlinear systems is
demonstrated.Comment: 8 pages. Revex 4.
Manejo e exploração sustentável de florestas naturais tropicais: opções, restrições e alternativas.
Introdução; Conceito e manejo florestal e sustentabilidade; CaracterÃsticas das florestas naturais tropicais; Formas de manejo florestal; Manejo de produtos não-madeireiros; Manejo de uso múltiplo; Manejo florestal em área com população; Modelo geral para pequena propriedade; condições gerais para o manejo florestal; Condições imediatas para implantação do manejo florestal.bitstream/CNPF-2009-09/40472/1/doc110.pd
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