Mud is a ubiquitous building material in Nigeria,perhaps this is the reason why it is hardly seen as the outright building material that it is.The most popular contribution of mud to Nigerian architecture can only be ...Mud is a ubiquitous building material in Nigeria,perhaps this is the reason why it is hardly seen as the outright building material that it is.The most popular contribution of mud to Nigerian architecture can only be seen in the ancient traditional huts all over the country.Although still a building material in the suburbs of the country,mud is seen as a relic of the past,a symbol of a primitive tale of Nigerian building construction.The primary effort here is to redefine mud as a“skin”with infinite possibilities of imagery and texture,rather than its typical application as a wall in Nigerian architecture.Mud is attempted to be expressed via a new geometric vocabulary by re-evaluating its surreptitious properties including its ability to behave like a formally defined NURBS(non-uniform rational basis spline)surface.The properties of mud and clay are unconventionally simulated in computer modelling and analysis software to understand the ways in which it can be optimized for advanced building applications.Streamlined calculations and algorithmic calculations serve as tools to discover the NURBS-propensity of mud.This provides a whole new low-cost construction opportunity for the building of irregularly flowing structures.展开更多
Plant populations at high elevation face extreme climatic conditions and resource limitations. The existence of distylous species at different elevations can help us investigate their adaptation to high altitudes, the...Plant populations at high elevation face extreme climatic conditions and resource limitations. The existence of distylous species at different elevations can help us investigate their adaptation to high altitudes, the evolution of their morphological characteristics, as well as their responses to limited resources. Here, 17 populations of Primula nivalis at different elevations were evaluated regarding variations in plant morphological characteristics, biomass allocation, and morphological plasticity in a heterogeneous environment. Our results demonstrate that heterogeneous environments can affect plant morphological characteristics and resource allocation in each sexual morph of these plants. Moreover,environmental variations reduced morphological plasticity in the two plant morphs, and the plasticity of long style(LS) plants was greater than that of short style(SS) plants. There were significant negative correlations between morphological characteristics and elevation, rainfall, temperature, and sunshine,and these are the main variables that affect morphological characteristics and resource allocation of both morphs of P. nivalis plants in heterogeneous environments. The morphological characteristics of P. nivalis plants transplanted from high to lower elevations were not significantly different in either population.LS plants had greater morphological plasticity and adaptability in heterogeneous environments than SS plants. Elevational gradients and heterogeneous environments differentiated both morphs of P. nivalis plants with regards to morphology as well as adaptations. LS plants showed a higher level of adaptability than SS plants.展开更多
The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warble...The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warbler (Acrocephalus scirpaceus) host nests. However, social information alerts hosts to see through the cuckoo’s mimetic disguise. In turn, this has promoted the evolution of a cuckoo polymorphism to thwart host recognition. Here we show by comparative analyses that parasitic cuckoos with hawk-like features (yellow eyes, barred underparts, yellow legs) are more likely to be polymorphic (29% of species) than those without (8% of species). Phylogenetic analyses confirm correlated evolution of hawk-like features and cuckoo polymorphism. We suggest that mimicry dynamics are particularly likely to promote the evolution of various guises in parasitic cuckoos to beat host defences.展开更多
文摘Mud is a ubiquitous building material in Nigeria,perhaps this is the reason why it is hardly seen as the outright building material that it is.The most popular contribution of mud to Nigerian architecture can only be seen in the ancient traditional huts all over the country.Although still a building material in the suburbs of the country,mud is seen as a relic of the past,a symbol of a primitive tale of Nigerian building construction.The primary effort here is to redefine mud as a“skin”with infinite possibilities of imagery and texture,rather than its typical application as a wall in Nigerian architecture.Mud is attempted to be expressed via a new geometric vocabulary by re-evaluating its surreptitious properties including its ability to behave like a formally defined NURBS(non-uniform rational basis spline)surface.The properties of mud and clay are unconventionally simulated in computer modelling and analysis software to understand the ways in which it can be optimized for advanced building applications.Streamlined calculations and algorithmic calculations serve as tools to discover the NURBS-propensity of mud.This provides a whole new low-cost construction opportunity for the building of irregularly flowing structures.
基金partially supported by the National Natural Science Foundation of China (NSFC, 31400279, 31860121)Funded by the Scientific Research Program of the Higher Education Institution of Xinjiang (XJEDU2016I042)
文摘Plant populations at high elevation face extreme climatic conditions and resource limitations. The existence of distylous species at different elevations can help us investigate their adaptation to high altitudes, the evolution of their morphological characteristics, as well as their responses to limited resources. Here, 17 populations of Primula nivalis at different elevations were evaluated regarding variations in plant morphological characteristics, biomass allocation, and morphological plasticity in a heterogeneous environment. Our results demonstrate that heterogeneous environments can affect plant morphological characteristics and resource allocation in each sexual morph of these plants. Moreover,environmental variations reduced morphological plasticity in the two plant morphs, and the plasticity of long style(LS) plants was greater than that of short style(SS) plants. There were significant negative correlations between morphological characteristics and elevation, rainfall, temperature, and sunshine,and these are the main variables that affect morphological characteristics and resource allocation of both morphs of P. nivalis plants in heterogeneous environments. The morphological characteristics of P. nivalis plants transplanted from high to lower elevations were not significantly different in either population.LS plants had greater morphological plasticity and adaptability in heterogeneous environments than SS plants. Elevational gradients and heterogeneous environments differentiated both morphs of P. nivalis plants with regards to morphology as well as adaptations. LS plants showed a higher level of adaptability than SS plants.
基金funded by the Natural Environment Research Council
文摘The resemblance of some parasitic cuckoos to Accipiter hawks has been known since ancient times. Recent experiments show that the hawk-like features of Common Cuckoos (Cuculus canorus) facilitate access to Reed Warbler (Acrocephalus scirpaceus) host nests. However, social information alerts hosts to see through the cuckoo’s mimetic disguise. In turn, this has promoted the evolution of a cuckoo polymorphism to thwart host recognition. Here we show by comparative analyses that parasitic cuckoos with hawk-like features (yellow eyes, barred underparts, yellow legs) are more likely to be polymorphic (29% of species) than those without (8% of species). Phylogenetic analyses confirm correlated evolution of hawk-like features and cuckoo polymorphism. We suggest that mimicry dynamics are particularly likely to promote the evolution of various guises in parasitic cuckoos to beat host defences.
