Amino acid composition of proteins as a product of molecular evolution   总被引：1，自引：0，他引：1  

T Ota  M Kimura 《Science (New York, N.Y.)》1971,174(5):150-153

The average amino acid composition of proteins is determined by the genetic code and by random base changes in evolution. Small but significant deviations from expected composition can be explained by selective constraint on amino acid substitutions. In particular, the deficiency of arginine in proteins has been caused by constraint, during evolution, on fixation of mutations substituting arginine for other amino acids.  相似文献   

Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6     

Chollet M  Guerin L  Uchida N  Fukaya S  Shimoda H  Ishikawa T  Matsuda K  Hasegawa T  Ota A  Yamochi H  Saito G  Tazaki R  Adachi S  Koshihara SY 《Science (New York, N.Y.)》2005,307(5706):86-89

We report that the organic salt (EDO-TTF)2PF6 with 3/4-filled-band (1/4-filled in terms of holes), which forms an organic metal with strong electron and lattice correlation, shows a highly sensitive response to photoexcitation. An ultrafast, photoinduced phase transition from the insulator phase to the metal phase can be induced with very weak excitation intensity at near room temperature. This response makes the material attractive for applications in switching devices with room-temperature operation. The observed photo-induced spectroscopic change shows that this photoinduced phase transition process is caused by the cooperative melting of charge ordering assisted by coherent phonon generation.  相似文献   

Smallholder reforestation and livelihoods in the humid tropics: a systematic mapping study     

Liz Ota  John Herbohn  Steve Harrison  Nestor Gregorio  Vera Lex Engel 《Agroforestry Systems》2018,92(6):1597-1609

Systematic mapping studies provide a snapshot of the literature based on systematic literature searches. In this systematic mapping study, the original research that links reforestation and livelihoods in the tropics was mapped and analysed to identify the trends, biases and gaps in the literature. In total, 339 papers from 92 journals were identified. Agroforestry Systems was the journal in which articles were most frequently published, and Cameroon and Indonesia the most frequently studied countries. The greatest number of authors came from the USA, and authors were most commonly affiliated with ICRAF. A limited collaboration between research groups in the tropical regions was identified. Anthropology and Social Sciences were the most frequent areas of research, especially in Africa. Latin America had more technical studies and more publications discussing payment for environmental services than the other regions. Based on the temporal analysis of the main terms in abstracts of the publications included, it was found that agriculture-related terms and terms related to the human component in the landscape were consistently prevalent in the literature relating reforestation and livelihoods throughout time. Agroforestry systems were especially important in small-scale reforestation and livelihoods. Trends, biases and gaps were discussed. Broader cooperation between tropical regions and between clusters of authors would be beneficial for research and practice.  相似文献   

The potential global distribution of <Emphasis Type="Italic">Chilo partellus</Emphasis>, including consideration of irrigation and cropping patterns     

Tania Yonow  Darren J. Kriticos  Noboru Ota  Johnnie Van Den Berg  William D. Hutchison 《Journal of pest science》2017,90(2):459-477

Chilo partellus is a major crop pest in Asia and Africa, and has recently spread to the Mediterranean region. Knowledge of its potential distribution can inform biosecurity policies aimed at limiting its further spread and efforts to reduce its impact in areas that are already invaded. Three models of the potential distribution of this insect have been published, each with significant shortcomings. We re-parameterized an existing CLIMEX model to address some parameter inconsistencies and to improve the fit to the known distribution of C. partellus. The resulting model fits the known distribution better than previous models, highlights additional risks in equatorial regions and reduces modelled risks in wet and extremely dry regions. We bring new insights into the role of irrigation in the potential spread of this invasive insect and compare its potential distribution with the present known distribution of its hosts. We also distinguish regions that are suitable for supporting persistent populations from those that may be at risk from ephemeral populations during favourable seasons. We present one of the first demonstrations of a new capability in CLIMEX to automatically estimate parameter sensitivity and model uncertainty. Our CLIMEX model highlights the substantial invasion risk posed by C. partellus to cropping regions in the Americas, Australia, China, Europe, New Zealand and West Africa. Its broad host range and reported impacts suggest that it should be a pest of significant concern to biosecurity agencies in these presently uninvaded regions.  相似文献