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Structure of yeast phosphoglycerate kinase 总被引:13,自引:0,他引:13
24.
Self-reproduction is central to biological life for long-term sustainability and evolutionary adaptation. Although these traits would also be desirable in many engineered systems, the principles of self-reproduction have not been exploited in machine design. Here we create simple machines that act as autonomous modular robots and are capable of physical self-reproduction using a set of cubes. 相似文献
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Sharon L. Weinberg Peter G. Bryant Glenn W. Milligan Richard Church A. D. Gordon Gildas Brossier Brigitte Escofier Kathleen M. Carley Frank Critchle 《Journal of Classification》1989,6(1):121-161
Affiliated to Astrophysics Div., Space Science Department, European Space Agency. 相似文献
27.
Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study 总被引:2,自引:0,他引:2
JA Mattison GS Roth TM Beasley EM Tilmont AM Handy RL Herbert DL Longo DB Allison JE Young M Bryant D Barnard WF Ward W Qi DK Ingram R de Cabo 《Nature》2012,489(7415):318-321
Calorie restriction (CR), a reduction of 10–40% in intake of a nutritious diet, is often reported as the most robust non-genetic mechanism to extend lifespan and healthspan. CR is frequently used as a tool to understand mechanisms behind ageing and age-associated diseases. In addition to and independently of increasing lifespan, CR has been reported to delay or prevent the occurrence of many chronic diseases in a variety of animals. Beneficial effects of CR on outcomes such as immune function, motor coordination and resistance to sarcopenia in rhesus monkeys have recently been reported. We report here that a CR regimen implemented in young and older age rhesus monkeys at the National Institute on Aging (NIA) has not improved survival outcomes. Our findings contrast with an ongoing study at the Wisconsin National Primate Research Center (WNPRC), which reported improved survival associated with 30% CR initiated in adult rhesus monkeys (7–14?years) and a preliminary report with a small number of CR monkeys. Over the years, both NIA and WNPRC have extensively documented beneficial health effects of CR in these two apparently parallel studies. The implications of the WNPRC findings were important as they extended CR findings beyond the laboratory rodent and to a long-lived primate. Our study suggests a separation between health effects, morbidity and mortality, and similar to what has been shown in rodents, study design, husbandry and diet composition may strongly affect the life-prolonging effect of CR in a long-lived nonhuman primate. 相似文献
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On characterizing optimization-based clustering methods 总被引:1,自引:1,他引:0
Peter Bryant 《Journal of Classification》1988,5(1):81-84
This paper suggests a simplification of a recent approach suggested by Windham to characterizing optimization-based clustering methods. The simplification is based on noting an analogy between certain quantities in Windham's formulation and corresponding quantities in mathematical statistics, particularly sufficient statistics and the exponential family of densities.He thanks an anonymous referee for several helpful comments. 相似文献
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Large-sample results for optimization-based clustering methods 总被引:1,自引:0,他引:1
Peter G. Bryant 《Journal of Classification》1991,8(1):31-44
Many common (nonhierarchical) clustering and classification methods are optimization-based methods, in the sense described
by Windham (1987) in this Journal. This paper gives some large sample properties for estimates derived by such methods. Under
appropriate conditions, such estimates converge with probability one to a limit, and are asymptotically normally distributed
around that limiting value. The conditions are satisfied by most of the common examples of optimization-based methods.
Prepared for the 2nd International Conference, International Federation of Classification Societies, Charlottesville, VA,
1989. Supported in part by summer research funds, Graduate School of Business Administration, University of Colorado at Denver. 相似文献