Cyclic dominance and biodiversity in well-mixed populations

Coevolutionary dynamics is investigated in chemical catalysis, biological evolution, social and economic systems. The dynamics of these systems can be analyzed within the unifying framework of evolutionary game theory. In this Letter, we show that even in well-mixed finite populations, where the dynamics is inherently stochastic, biodiversity is possible with three cyclic-dominant strategies. We show how the interplay of evolutionary dynamics, discreteness of the population, and the nature of the interactions influences the coexistence of strategies. We calculate a critical population size above which coexistence is likely.     

An asymptotic result and a stability criterion for linear nonautonomous delay difference equations

Linear delay difference equations with variable coefficients and constant delays are considered. By the use of an appropriate solution of the so called generalized characteristic equation, an asymptotic result is obtained and a stability criterion is established.     

Energy spectra and asymmetries of neutrons emitted after muon capture

Inclusive energy spectra and the energy dependence of the asymmetry parameter have been measured for neutrons emitted after muon capture in O, Si, Ca and Pb. In addition a neutron-neutron coincidence measurement has been performed for Ca. The results of these measurements confirm the exponential shape of the energy spectra and the positive asymmetry observed by Sundelin and Edelstein. The observation of neutrons with energies above 50 MeV and the observation of simultaneous emission of two high-energy neutrons suggest the importance of short-range nucleonnucleon correlations in this process.     

Neodymium luminescence in chalcogenides of europium-gallium: EuGaS4 and EuGa2Se4

Photoluminescence of chalcogenides of europium-gallium, EuGa₂S₄ and EuGa₂Se₄, doped with neodymium is investigated. The positions of Stark levels are determined from the spectra. The symmetry of luminescence centres is shown to be lower than cubic and the existence of nonequivalent centers is established. At 77 K the decay time of luminescence from the excited levels of Nd³⁺ depends on the spin of the states. That indicates a slow relaxation rate in the crystals under investigation. It is probable that these crystals can be used as effective luminophores.     

On conformal mapping and linear measure

Journal d'Analyse Mathématique -     

Experimental limits on the production of fractionally charged particles in proton-nucleus and neutrino-nucleus collisions

A search for fractionally chargedQ=1/3 (2/3) particles of different properties of interaction produced in (anti)neutrino-nucleus and in protonnucleus collisions was performed using the scintillator system of the CHARM neutrino detector at the CERN SPS. No events of the cases considered were found. In (anti)neutrino beams production was found to be less than a few times 10^?5 per interaction of a beam particle. In a proton beam an upper limit on the production cross section of ～10^?40 cm² was obtained.     

A facile one‐pot synthesis of tetrahydropyrimidines part 3 Synthesis of [alkanediylbis(3‐alkyl/aralkyl/aryl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)bis(arylmethanones) and [1,4‐phenylenebis(3‐phenyl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(phenylmethanone)

A facile one‐pot synthetic strategy has been developed for novel [alkanediylbis(3‐alkyl/aralkyl/ aryl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(arylmethanones) 2a‐c, 2e‐m and [1,4‐phenylenebis(3‐phenyl‐3,6‐dihydropyrimidine‐1,5(2H)‐diyl)]bis(phenylmethanone) 2d by refluxing enaminones 1a‐f in methanol with diamines and formaldehyde.     

The Influence of the Dispersion and Vertical Divergence on the Reflection Curve of a Double-crystal Arrangement

The influence of the dispersion and vertical divergence on the half width of the reflection curves was investigated using a double-crystal arrangement where the second crystal could be rotated about an axis parallel to the beam reflected by the first crystal. The experimentally measured dependence of the half width of the reflection curves on the angle of rotation φ is accurately confirmed by geometrical considerations.