35,874 research outputs found
Phase transitions in dependence of apex predator decaying ratio in a cyclic dominant system
Cyclic dominant systems, like rock-paper-scissors game, are frequently used
to explain biodiversity in nature, where mobility, reproduction and
intransitive competition are on stage to provide the coexistence of
competitors. A significantly new situation emerges if we introduce an apex
predator who can superior all members of the mentioned three-species system. In
the latter case the evolution may terminate into three qualitatively different
destinations depending on the apex predator decaying ratio . In particular,
the whole population goes extinct or all four species survive or only the
original three-species system remains alive as we vary the control parameter.
These solutions are separated by a discontinuous and a continuous phase
transitions at critical values. Our results highlight that cyclic dominant
competition can offer a stable way to survive even in a predator-prey-like
system that can be maintained for large interval of critical parameter values.Comment: version to appear in EPL. 7 pages, 7 figure
Invasion controlled pattern formation in a generalized multi-species predator-prey system
Rock-scissors-paper game, as the simplest model of intransitive relation
between competing agents, is a frequently quoted model to explain the stable
diversity of competitors in the race of surviving. When increasing the number
of competitors we may face a novel situation because beside the mentioned
unidirectional predator-prey-like dominance a balanced or peer relation can
emerge between some competitors. By utilizing this possibility in the present
work we generalize a four-state predator-prey type model where we establish two
groups of species labeled by even and odd numbers. In particular, we introduce
different invasion probabilities between and within these groups, which results
in a tunable intensity of bidirectional invasion among peer species. Our study
reveals an exceptional richness of pattern formations where five quantitatively
different phases are observed by varying solely the strength of the mentioned
inner invasion. The related transition points can be identified with the help
of appropriate order parameters based on the spatial autocorrelation decay, on
the fraction of empty sites, and on the variance of the species density.
Furthermore, the application of diverse, alliance-specific inner invasion rates
for different groups may result in the extinction of the pair of species where
this inner invasion is moderate. These observations highlight that beyond the
well-known and intensively studied cyclic dominance there is an additional
source of complexity of pattern formation that has not been explored earlier.Comment: 8 pages, 8 figures. To appear in PR
Three dimensional Lifshitz black hole and the Korteweg-de Vries equation
We consider a solution of three dimensional New Massive Gravity with a
negative cosmological constant and use the AdS/CTF correspondence to inquire
about the equivalent two dimensional model at the boundary. We conclude that
there should be a close relation with the Korteweg-de Vries equation.Comment: 4 page
The Likelihood Ratio Test and Full Bayesian Significance Test under small sample sizes for contingency tables
Hypothesis testing in contingency tables is usually based on asymptotic
results, thereby restricting its proper use to large samples. To study these
tests in small samples, we consider the likelihood ratio test and define an
accurate index, the P-value, for the celebrated hypotheses of homogeneity,
independence, and Hardy-Weinberg equilibrium. The aim is to understand the use
of the asymptotic results of the frequentist Likelihood Ratio Test and the
Bayesian FBST -- Full Bayesian Significance Test -- under small-sample
scenarios. The proposed exact P-value is used as a benchmark to understand the
other indices. We perform analysis in different scenarios, considering
different sample sizes and different table dimensions. The exact Fisher test
for tables that drastically reduces the sample space is also
discussed. The main message of this paper is that all indices have very similar
behavior, so the tests based on asymptotic results are very good to be used in
any circumstance, even with small sample sizes
Holographic Superconductors with various condensates in Einstein-Gauss-Bonnet gravity
We study holographic superconductors in Einstein-Gauss-Bonnet gravity. We
consider two particular backgrounds: a -dimensional Gauss-Bonnet-AdS black
hole and a Gauss-Bonnet-AdS soliton. We discuss in detail the effects that the
mass of the scalar field, the Gauss-Bonnet coupling and the dimensionality of
the AdS space have on the condensation formation and conductivity. We also
study the ratio for various masses of the scalar field and
Gauss-Bonnet couplings.Comment: 21 pages, 10 figures. accepted for publication in PR
Inclusive hadron and photon production at LHC in dipole momentum space
Using a momentum space model for the dipole scattering amplitude we present
an analysis of the saturation effects at LHC energies, describing the data on
proton-proton and proton-lead collisions. The model is based on the asymptotic
solutions of the Balitsky-Kovchegov equation, being ideal in the saturation
domain where the target wave function has a high occupation number. We also
make predictions for the nuclear modification ratios on charged hadron and
prompt photon production in the forward region, where the high parton density
effects are important.Comment: New section added and typos corrected. To be published in PR
Structural anomalies for a three dimensional isotropic core-softened potential
Using molecular dynamics simulations we investigate the structure of a system
of particles interacting through a continuous core-softened interparticle
potential. We found for the translational order parameter, t, a local maximum
at a density and a local minimum at . Between and , the parameter
anomalously decreases upon pressure. For the orientational order parameter,
, was observed a maximum at a density . For densities between and , both the
translational (t) and orientational () order parameters have anomalous
behavior. We know that this system also exhibits density and diffusion anomaly.
We found that the region in the pressure-temperature phase-diagram of the
structural anomaly englobes the region of the diffusion anomaly that is larger
than the region limited by the temperature of maximum density. This cascade of
anomalies (structural, dynamic and thermodynamic) for our model has the same
hierarchy of that one observed for the SPC/E water.Comment: 19 pages, 8 figure
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