111,981 research outputs found
Simplicial minisuperspace models in the presence of a massive scalar field with arbitrary scalar coupling
We extend previous simplicial minisuperspace models to account for arbitrary
scalar coupling \eta R\phi^2.Comment: 24 pages and 9 figures. Accepted for publication by Classical and
Quantum Gravit
Anisotropic simplicial minisuperspace model
The computation of the simplicial minisuperspace wavefunction in the case of
anisotropic universes with a scalar matter field predicts the existence of a
large classical Lorentzian universe like our own at late timesComment: 19 pages, Latex, 6 figure
A Highly Predictive Ansatz for Leptonic Mixing and CP Violation
We suggest a simple highly predictive ansatz for charged lepton and light
neutrino mass matrices, based on the assumption of universality of Yukawa
couplings. Using as input the charged lepton masses and light neutrino masses,
the six parameters characterizing the leptonic mixing matrix , are
predicted in terms of a single phase , which takes a value around
. Correlations among variuos physical quantities are
obtained, in particular is predicted as a function of
, and , and
restricted to the range .Comment: 9 pages, 4 figure
Stochastic group selection model for the evolution of altruism
We study numerically and analytically a stochastic group selection model in
which a population of asexually reproducing individuals, each of which can be
either altruist or non-altruist, is subdivided into reproductively isolated
groups (demes) of size . The cost associated with being altruistic is
modelled by assigning the fitness , with , to the
altruists and the fitness 1 to the non-altruists. In the case that the
altruistic disadvantage is not too large, we show that the finite
fluctuations are small and practically do not alter the deterministic results
obtained for . However, for large these fluctuations
greatly increase the instability of the altruistic demes to mutations. These
results may be relevant to the dynamics of parasite-host systems and, in
particular, to explain the importance of mutation in the evolution of parasite
virulence.Comment: 12 pages, 7 figure
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