The Effect of Recombination on the Neutral Evolution of Genetic Robustness

Conventional population genetics considers the evolution of a limited number of genotypes corresponding to phenotypes with different fitness. As model phenotypes, in particular RNA secondary structure, have become computationally tractable, however, it has become apparent that the context dependent effect of mutations and the many-to-one nature inherent in these genotype-phenotype maps can have fundamental evolutionary consequences. It has previously been demonstrated that populations of genotypes evolving on the neutral networks corresponding to all genotypes with the same secondary structure only through neutral mutations can evolve mutational robustness [Nimwegen {\it et al.} Neutral evolution of mutational robustness, 1999 PNAS], by concentrating the population on regions of high neutrality. Introducing recombination we demonstrate, through numerically calculating the stationary distribution of an infinite population on ensembles of random neutral networks that mutational robustness is significantly enhanced and further that the magnitude of this enhancement is sensitive to details of the neutral network topology. Through the simulation of finite populations of genotypes evolving on random neutral networks and a scaled down microRNA neutral network, we show that even in finite populations recombination will still act to focus the population on regions of locally high neutrality.Comment: Accepted for publication in Math. Biosci. as part of the proceedings of BIOCOMP 200

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"制御不能な市場価格撹乱の存在がみとめられるとき,公共部門調整システムの展開過程での生産量決定を任意の価格体系をベースにとって作業することで社会的公正水準を増幅することがはたしてできるのかという設問がストレートな形でうまれる.これはまさに潜在価格水準決定にかかわる基本的論点である.本稿では,まず開放系の経済システムモデルのシナリオで潜在価格決定に関する情報とその安定性をめぐる若干の問題を考える.つぎにこのシステムモデルの説明を試みる.第3に,次善型の最適厚生水準を保証できる要件をクリアする.最後に潜在価格決定の作業をとおして初期時点の厚生水準値一般からの,社会的厚生水準最適値導出に関する各種の情報選択問題とそれら情報の安定性をめぐる諸問題を吟味する.(付記:本稿は昨年8月国立オーストラリア大学での国際計量経済学会において報告した論文の第2章と第3章をまとめて全面的にかき改めたものである.)

Measurement of isomer production ratio in neutron-induced reaction on 112Cd to study the s-process origin of 115Sn

A beta-decay unstable isomer with a half-life of 14.1 y at 264 keV in 113Cd is a branching point in the s process, from which a weak branch reaches to a rare tin isotope 115Sn whose astrophysical origin has been an open problem. We have measured rays decaying to the ground state or the isomer in the 112Cd(n, gamma)113Cd reaction using high-energy resolution detectors in conjunction with a time-of-ight method. The relative production ratios of the isomer to the total following the neutron capture reactions on 112Cd have been evaluatedin the energy region of up to 9 keV, and spin and parity of several resonances have been assigned.The 16the international symposium on nuclei in cosmo

Isomer prodcution ratio of the 112Cd(n, gamma)113Cd reaction in an s-process branching point

A beta-decay unstable isomer with a half-life of 14.1 y at 264 keV in 113Cd is a branching point in the s process, from which a weak branch reaches to a rare tin isotope 115Sn whose astrophysical origin has been an open problem. We have measured rays decaying to the ground state or the isomer in the 112Cd(n, gamma)113Cd reaction using high-energy resolution detectors in conjunction with a time-of-ight method. The relative production ratios of the isomer to the total following the neutron capture reactions on 112Cd have been evaluatedin the energy region of up to 9 keV, and spin and parity of several resonances have been assigned