Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to de...Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to describe the level of player＇s rationality and noise intensity in environment are introduced. In contrast with the fixation probability method that used in a noiseless case, the introducing of the noise intensity parameter makes the process an ergodic Markov process and based on the limit distribution of the process, we can analysis the evolutionary stable strategy （ESS） of the games. We illustrate the effects of the two parameters on the ESS of games using the Prisoner＇s dilemma games （PDG） and the snowdrift games （SG）. We also compare the ESS of our model with that of the replicator dynamics in infinite size populations. The results are determined by simulation experiments.展开更多
Piperock, a kind of characteristic ichnofabrics in Phanerozoic, was thought to decline gradually from Cambrian to Ordovician. A new compilation on the occurrences of the Cambrian and Ordovician piperocks of China and ...Piperock, a kind of characteristic ichnofabrics in Phanerozoic, was thought to decline gradually from Cambrian to Ordovician. A new compilation on the occurrences of the Cambrian and Ordovician piperocks of China and the world shows that piperocks generally flourished in Cambrian and declined in Ordovician, but a sharp decrease occurred during Middle and Late Cambrian. The case-study on the piperocks from the Lower-Middle Ordovician Hongshiya Formation at Dabaochang of Qiaojia, northern Yunnan Province, Southwest China indicates that the forming and preservation of piperocks were controlled by the depositional environment, the intensities of predation, competition, bioturbation, and the contents of nutrition and oxygen in watermass. A careful study on the development of the Cambrian and Ordovician piperocks suggests that the decrease of nearshore siliciclastic sediments and the low contents of oxygen and nutrition in the watermass may have contributed to the decline of piperocks in Middle and Late Cambrian.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 71071119 and 60574071
文摘Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to describe the level of player＇s rationality and noise intensity in environment are introduced. In contrast with the fixation probability method that used in a noiseless case, the introducing of the noise intensity parameter makes the process an ergodic Markov process and based on the limit distribution of the process, we can analysis the evolutionary stable strategy （ESS） of the games. We illustrate the effects of the two parameters on the ESS of games using the Prisoner＇s dilemma games （PDG） and the snowdrift games （SG）. We also compare the ESS of our model with that of the replicator dynamics in infinite size populations. The results are determined by simulation experiments.
基金supported by National Natural Science Foundation of China (Grant Nos. 40972020, 40825006)Chinese Academy of Sciences (Grant No. KZCX2-YW-Q05-01)State Key Laboratory of Palaeobiology and Stratigraphy
文摘Piperock, a kind of characteristic ichnofabrics in Phanerozoic, was thought to decline gradually from Cambrian to Ordovician. A new compilation on the occurrences of the Cambrian and Ordovician piperocks of China and the world shows that piperocks generally flourished in Cambrian and declined in Ordovician, but a sharp decrease occurred during Middle and Late Cambrian. The case-study on the piperocks from the Lower-Middle Ordovician Hongshiya Formation at Dabaochang of Qiaojia, northern Yunnan Province, Southwest China indicates that the forming and preservation of piperocks were controlled by the depositional environment, the intensities of predation, competition, bioturbation, and the contents of nutrition and oxygen in watermass. A careful study on the development of the Cambrian and Ordovician piperocks suggests that the decrease of nearshore siliciclastic sediments and the low contents of oxygen and nutrition in the watermass may have contributed to the decline of piperocks in Middle and Late Cambrian.
