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The term"extreme environments"describes the conditions that deviate from what mesophilic cells can tolerate.These conditions are"extreme"in the eye of mankind,but they may be suitable or even essential living conditions for most microorganisms.Hyperthermophilic microorganisms form a branch at the root of the phylogenetic tree,indicating that early life originated from extreme environments similar to that of modern deep-sea hydrothermal vents,which are characterized by high-temperature and oxygen-limiting conditions.During the inevitable cooling and gradual oxidation process on Earth,microorganisms developed similar mechanisms of adaptation.By studying modern extremophiles,we may be able to decode the mysterious history of their genomic evolution and to reconstruct early life.Because life itself is a process of energy uptake to maintain a dissipative structure that is not in thermodynamic equilibrium,the energy metabolism of microorganisms determines the pathway of evolution,the structure of an ecosystem,and the physiology of cells."Following energy"is an essential approach to understand the boundaries of life and to search for life beyond Earth. 相似文献
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《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2012,112(2):105-116
This paper uses a case study on the evolution of the Rhine river delta to illustrate the coevolution of the environment, the technology used to exploit it, and the institutions governing it. Three strands are interwoven: (1) Achieving equilibrium between protecting and utilizing land is difficult. In this area, as a result of exploitation, agriculture on fertile peat is succeeded by stock raising on infertile peat, peat extraction, inundation, and drainage to regain fertile soil. (2) In the dynamic between collective and individual action that accompanies these changes, individuals beget institutions and institutions beget individuals. (3) New technologies are invented, helping overcome challenges posed by the natural environment. Their unexpected consequences undermine the solutions found, leading to new technologies, etc. The ultimate cause is the interaction between human cognition and action. Our cognition is limited in the number of dimensions it can simultaneously handle, and our action (directly or indirectly) affects all the dimensions of the complex adaptive system that is the environment, triggering unintended consequences, and new actions. This feedback takes the system from perceived challenges to solutions to new, unintended challenges, driving the region further and further from its point of departure, towards the bottom of the sea. 相似文献
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A comprehensive compilation and systematic analysis of known early and middle Permian brachiopod faunas shows that the early Permian brachiopod faunas comprise three realms, six regions, and eleven provinces, while those of the middle Permian comprise three realms, four regions, and eight provinces. A comparison and analysis of brachiopod faunal patterns reveal a coevolution between global brachiopod paleobiogeography and tectonopaleogeography during the early–middle Permian. Although temperature/latitude is the main factor controlling the formation of three realms, tectonopaleogeographic factors determine the temperature/latitude in which the continents were located. The ‘continental barrier' of Pangea, as a ‘central axis' continent, divided the three realms into six regions, which indicates that the formation of biogeographic regions was controlled mainly by the tectonopaleogeographic factors. The evolution of tectonopaleogeography was sometimes a long-term process, so that the biogeographic regions(or provinces) controlled by tectonopaleogeography displayed relative stability. Shifts in the nature of biogeographic provinces(e.g., from cool water to warm water, and vice versa), extensions or narrowing of geographical ranges, and recombinations of some provinces were all related to regional tectonic evolution. The study of the coevolution between brachiopod paleobiogeography and tectonopaleogeography not only accounts for the formation mechanisms of brachiopod paleobiogeographic patterns during the early–middle Permian, but also provides evidences for the locations and configurations of oceans and plates(blocks) during this period. 相似文献
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Ivan Blecic Arnaldo Cecchini 《International journal of geographical information science》2013,27(3):349-374
The objective of this computational study was to investigate to which extent the availability and the way of use of historical maps may affect the quality of the calibration process of cellular automata (CA) urban models. The numerical experiments are based on a constrained CA applied to a case study. Since the model depends on a large number of parameters, we optimize the CA using cooperative coevolutionary particle swarms, which is an approach known for its ability to operate effectively in search spaces with a high number of dimensions. To cope with the relevant computational cost related to the high number of CA simulations required by our study, we use a parallelized CA model that takes advantage of the computing power of graphics processing units. The study has shown that the accuracy of simulations can be significantly influenced by both the number and position in time of the historical maps involved in the calibration. 相似文献
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