Spatial interactions are considered an important factor influencing a variety of evolutionary processes that take place in structured populations.It still remains an open problem to fully understand evolutionary game ...Spatial interactions are considered an important factor influencing a variety of evolutionary processes that take place in structured populations.It still remains an open problem to fully understand evolutionary game dynamics on networks except for certain limiting scenarios such as weak selection.Here we study the evolutionary dynamics of spatial games under strong selection where strategy evolution of individuals becomes deterministic in a fashion of winners taking all.We show that the long term behavior of the evolutionary process eventually converges to a particular basin of attraction,which is either a periodic cycle or a single fixed state depending on specific initial conditions and model parameters.In particular,we find that symmetric starting configurations can induce an exceedingly long transient phase encompassing a large number of aesthetic spatial patterns including the prominent kaleidoscopic cooperation.Our finding holds for any population structure and a broad class of finite games beyond the Prisoner’s Dilemma.Our work offers insights into understanding evolutionary dynamics of spatially extended systems ubiquitous in biology and ecology.展开更多
This study reviewed the policies and outcomes of international support for forest management in Nepal and answered whether international support on forest management in developing countries resulted in positive socioe...This study reviewed the policies and outcomes of international support for forest management in Nepal and answered whether international support on forest management in developing countries resulted in positive socioeconomic and environmental outcomes at local communities. The evaluation is based on the socio-ecological theory and synergies-tradeoff model of forestry ecosystems goods and services. The study shows that the international interventions influenced national policies and community forestry practices, which contributed to the remarkable increase of forest stock. The new forestry institutions increased timber product supplies to urban users and contributed to offsetting of greenhouse gas emission of affluent societies in overseas. However, the intervention spoiled centuries of old forestry practices, which had contributed to the evolvement of socio-ecological condition, sustained local economy and environment systems. The new forestry institutions and practices locked local opportunities of multipurpose uses of forest, worsened water yield and local knowledge, and hampered local economic activities. Consequently they affected habitat diversities for forest based species, and forest resource supplies for sustaining agrobiodiversities and local food security. In reality the interventions increased benefit to distant users (urban users in the country and affluent societies in overseas) and further marginalized local communities and particularly socially disadvantaged people. The paper shows that the international forestry policies and supports are technically wrong or poorly based on science which is against their promise of providing better technical supports and benefiting local communities in developing countries. It argues that the interventions created many complexities in forestry institutions and practices which require too costly endeavor to change and address the local socioeconomic and environmental problems. The paper has explained the root cause of the international policy problem on many schools of thought.展开更多
Red,blue and white; the national pavilions for the 2010 World Expo, which lasts from May 1 to October 31,use different colors to capture their essence, making the Expo
基金support from NSFC,China(62036002,62273226)is gratefully acknowledgedsupported by the Fundamental Research Funds for Central Universities,Xidian University,China(JB210414).
文摘Spatial interactions are considered an important factor influencing a variety of evolutionary processes that take place in structured populations.It still remains an open problem to fully understand evolutionary game dynamics on networks except for certain limiting scenarios such as weak selection.Here we study the evolutionary dynamics of spatial games under strong selection where strategy evolution of individuals becomes deterministic in a fashion of winners taking all.We show that the long term behavior of the evolutionary process eventually converges to a particular basin of attraction,which is either a periodic cycle or a single fixed state depending on specific initial conditions and model parameters.In particular,we find that symmetric starting configurations can induce an exceedingly long transient phase encompassing a large number of aesthetic spatial patterns including the prominent kaleidoscopic cooperation.Our finding holds for any population structure and a broad class of finite games beyond the Prisoner’s Dilemma.Our work offers insights into understanding evolutionary dynamics of spatially extended systems ubiquitous in biology and ecology.
文摘This study reviewed the policies and outcomes of international support for forest management in Nepal and answered whether international support on forest management in developing countries resulted in positive socioeconomic and environmental outcomes at local communities. The evaluation is based on the socio-ecological theory and synergies-tradeoff model of forestry ecosystems goods and services. The study shows that the international interventions influenced national policies and community forestry practices, which contributed to the remarkable increase of forest stock. The new forestry institutions increased timber product supplies to urban users and contributed to offsetting of greenhouse gas emission of affluent societies in overseas. However, the intervention spoiled centuries of old forestry practices, which had contributed to the evolvement of socio-ecological condition, sustained local economy and environment systems. The new forestry institutions and practices locked local opportunities of multipurpose uses of forest, worsened water yield and local knowledge, and hampered local economic activities. Consequently they affected habitat diversities for forest based species, and forest resource supplies for sustaining agrobiodiversities and local food security. In reality the interventions increased benefit to distant users (urban users in the country and affluent societies in overseas) and further marginalized local communities and particularly socially disadvantaged people. The paper shows that the international forestry policies and supports are technically wrong or poorly based on science which is against their promise of providing better technical supports and benefiting local communities in developing countries. It argues that the interventions created many complexities in forestry institutions and practices which require too costly endeavor to change and address the local socioeconomic and environmental problems. The paper has explained the root cause of the international policy problem on many schools of thought.
文摘Red,blue and white; the national pavilions for the 2010 World Expo, which lasts from May 1 to October 31,use different colors to capture their essence, making the Expo
