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Simulated emergence of cyclic sexual-asexual reproduction
Motivated by the cyclic pattern of reproductive regimes observed in some
species of green flies (``{\it aphids}''), we simulate the evolution of a
population enduring harsh seasonal conditions for survival. The reproductive
regime of each female is also seasonal in principle and genetically acquired,
and can mutate for each newborn with some small probability. The results show a
sharp transition at a critical value of the survival probability in the winter,
between a reproductive regime in the fall that is predominantly sexual, for low
values of this probability, or asexual, for high values.Comment: 9 pages, 4 figures, requires RevTe
Two loops calculation in chiral perturbation theory and the unitarization program of current algebra
In this paper we compare two loop Chiral Perturbation Theory (ChPT)
calculation of pion-pion scattering with the unitarity second order correction
to the current algebra soft-pion theorem. It is shown that both methods lead to
the same analytic structure for the scattering amplitude.Comment: 13 pages, Revtex 3.0, no figures, submitted to Phys. Lett.
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