1,669 research outputs found
Gravitational Mesoscopic Constraints in Cosmological Dark Matter Halos
We present an analysis of the behaviour of the `coarse-grained'
(`mesoscopic') rank partitioning of the mean energy of collections of particles
composing virialized dark matter halos in a Lambda-CDM cosmological simulation.
We find evidence that rank preservation depends on halo mass, in the sense that
more massive halos show more rank preservation than less massive ones. We find
that the most massive halos obey Arnold's theorem (on the ordering of the
characteristic frequencies of the system) more frequently than less massive
halos. This method may be useful to evaluate the coarse-graining level (minimum
number of particles per energy cell) necessary to reasonably measure signatures
of `mesoscopic' rank orderings in a gravitational system.Comment: LaTeX, 15 pages, 3 figures. Accepted for publication in Celestial
Mechanics and Dynamical Astronomy Journa
Aplicação foliar de aminoácidos e a qualidade das uvas da cv. Benitaka.
bitstream/item/38921/1/BPD-23-2010-ID-48-1.pd
A supercritical series analysis for the generalized contact process with diffusion
We study a model that generalizes the CP with diffusion. An additional
transition is included in the model so that at a particular point of its phase
diagram a crossover from the directed percolation to the compact directed
percolation class will happen. We are particularly interested in the effect of
diffusion on the properties of the crossover between the universality classes.
To address this point, we develop a supercritical series expansion for the
ultimate survival probability and analyse this series using d-log Pad\'e and
partial differential approximants. We also obtain approximate solutions in the
one- and two-site dynamical mean-field approximations. We find evidences that,
at variance to what happens in mean-field approximations, the crossover
exponent remains close to even for quite high diffusion rates, and
therefore the critical line in the neighborhood of the multicritical point
apparently does not reproduce the mean-field result (which leads to )
as the diffusion rate grows without bound
Análise espectral de dados SMMR para estudo de padrões de Inundação do Pantanal.
Inundation seasonal patterns are important in the understanding of tropical floodplain ecosystems dynamics. In this study, we have analyzed data derived from 37-GHz polarization differences observed by the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR). The passive microwave observations, for 10 Pantanal subregioes, provide an robust signature of inundation dynamics in large wetlands such as the Pantanal. The time series was obtained taking into account the differences between vertically and horizontally polarized brightness temperatures providing a sensitive indicator of the surface water against a vegetation land surface background. Each time series was analyzed by applying the gradient pattern analysis on a multiresolution representation obtained from wavelet decomposition /reconstrution technique. The main result have shown similar variability patterns for the following groups of subregions: (i) Miranda and Piquiri; (ii) Negro and Nhecolandia; (iii) Corixo, Paraguay, Cuiabá and Taquari fan; and (iv) Taquari river and Nabileque. Some hydrological aspects are discussed in order to understand the clusterization found from our results
Effect of humic substances and weather conditions on leaf biochemical changes of fertigated guava tree, during orchard establishment.
No Vale do São Francisco, em Petrolina - PE, as substâncias húmicas têm sido aplicadas em fertirrigação de espécies frutÃferas, baseando-se nas informações sobre melhorias que proporcionam ao solo, aumento de absorção de nutrientes, metabolismo e crescimento de plantas, obtidas em diferentes locais e culturas. Porém, existe pouca informação sobre as respostas das planta à aplicação de substâncias húmicas nas condições locais de solo, clima e sistema de cultivo. Assim, este trabalho avaliou a resposta metabólica de goiabeiras, em fase de formação, à fertirrigação com substâncias húmicas, e sua correlação com as condições climáticas em Petrolina - PE. Os tratamentos foram aplicação de esterco no solo combinada com a fertirrigação com fertilizantes minerais e com substâncias húmicas. Os tratamentos de fertirrigação e a idade das plantas não apresentaram resultados conclusivos quanto aos teores de carboidratos, proteÃnas e aminoácidos nas folhas de goiabeiras em formação. Por outro lado, os teores foliares dessas moléculas respondem à s condições climáticas
A Note on the Integral Formulation of Einstein's Equations Induced on a Braneworld
We revisit the integral formulation (or Green's function approach) of
Einstein's equations in the context of braneworlds. The integral formulation
has been proposed independently by several authors in the past, based on the
assumption that it is possible to give a reinterpretation of the local metric
field in curved spacetimes as an integral expression involving sources and
boundary conditions. This allows one to separate source-generated and
source-free contributions to the metric field. As a consequence, an exact
meaning to Mach's Principle can be achieved in the sense that only
source-generated (matter fields) contributions to the metric are allowed for;
universes which do not obey this condition would be non-Machian. In this paper,
we revisit this idea concentrating on a Randall-Sundrum-type model with a
non-trivial cosmology on the brane. We argue that the role of the surface term
(the source-free contribution) in the braneworld scenario may be quite subtler
than in the 4D formulation. This may pose, for instance, an interesting issue
to the cosmological constant problem.Comment: 10 pages, no figures, accepted for publication in the General
Relativity and Gravitation Journa
On the Formation of Copper Linear Atomic Suspended Chains
We report high resolution transmission electron microscopy and classical
molecular dynamics simulation results of mechanically stretching copper
nanowires conducting to linear atomic suspended chains (LACs) formation. In
contrast with some previous experimental and theoretical work in literature
that stated that the formation of LACs for copper should not exist our results
showed the existence of LAC for the [111], [110], and [100] crystallographic
directions, being thus the sequence of most probable occurence.Comment: 4 pages, 3 figure
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