Hasil untuk "Evolution"

M. Kanehisa

In this era of high‐throughput biology, bioinformatics has become a major discipline for making sense out of large‐scale datasets. Bioinformatics is usually considered as a practical field developing databases and software tools for supporting other fields, rather than a fundamental scientific discipline for uncovering principles of biology. The KEGG resource that we have been developing is a reference knowledge base for biological interpretation of genome sequences and other high‐throughput data. It is now one of the most utilized biological databases because of its practical values. For me personally, KEGG is a step toward understanding the origin and evolution of cellular organisms.

Jie Cui, Fang Li, Zhènglì Shí

Severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) are two highly transmissible and pathogenic viruses that emerged in humans at the beginning of the 21st century. Both viruses likely originated in bats, and genetically diverse coronaviruses that are related to SARS-CoV and MERS-CoV were discovered in bats worldwide. In this Review, we summarize the current knowledge on the origin and evolution of these two pathogenic coronaviruses and discuss their receptor usage; we also highlight the diversity and potential of spillover of bat-borne coronaviruses, as evidenced by the recent spillover of swine acute diarrhoea syndrome coronavirus (SADS-CoV) to pigs. Coronaviruses have a broad host range and distribution, and some highly pathogenic lineages have spilled over to humans and animals. Here, Cui, Li and Shi explore the viral factors that enabled the emergence of diseases such as severe acute respiratory syndrome and Middle East respiratory syndrome.

Esteban Real, A. Aggarwal, Yanping Huang et al.

The effort devoted to hand-crafting neural network image classifiers has motivated the use of architecture search to discover them automatically. Although evolutionary algorithms have been repeatedly applied to neural network topologies, the image classifiers thus discovered have remained inferior to human-crafted ones. Here, we evolve an image classifier— AmoebaNet-A—that surpasses hand-designs for the first time. To do this, we modify the tournament selection evolutionary algorithm by introducing an age property to favor the younger genotypes. Matching size, AmoebaNet-A has comparable accuracy to current state-of-the-art ImageNet models discovered with more complex architecture-search methods. Scaled to larger size, AmoebaNet-A sets a new state-of-theart 83.9% top-1 / 96.6% top-5 ImageNet accuracy. In a controlled comparison against a well known reinforcement learning algorithm, we give evidence that evolution can obtain results faster with the same hardware, especially at the earlier stages of the search. This is relevant when fewer compute resources are available. Evolution is, thus, a simple method to effectively discover high-quality architectures.

R. Lanfear, P. Frandsen, A. Wright et al.

K. Price, R. Storn, J. Lampinen

Benjamin M. Bolker, Mollie E. Brooks, C. Clark et al.

R. Storn, K. Price

R. May

S. Taylor, S. McLennan

G. Brady

In 1985, the National Academy of Sciences sponsored a conference in Annapolis, Maryland, to discuss common property resource management. This conference was a watershed in the development of the theoretical underpinning of institutional design for successful common pool resource (CPR) management. Since then, an international network of over 2,000 researchers has developed, and the International Association for the Study of Common Property (IASCP), formed in 1989, has held two successful international conferences. Dominating the intellectual evolution of the field has been the work of Elinor Ostrom, co-director of the Workshop in Political Theory and Policy Analysis at Indiana University. Her book, Governing the Commons, presents a lucid exposition of the current state of institutional analysis of common property problems. Part of the Cam-bridge series on Political Economy of Institutions and Decisions, the book addresses how common pool resources may be managed successfully without falling prey to the "tragedy of the commons." Common pool resources are characterized by subtractability (i.e., withdrawal by one user reduces the amount of the resource left for other users) and joint use by a group of appropriators. Thus, a common village grazing field has forage for a limited number of beasts, and all the villagers are entitled to pasture their animals on the field. Community rules of access and management are required to sustain the field from season to season. Problems in managing CPRs arise when the rational individual determines that he will still have access to the resource even if he does not fully contribute to its maintenance (the "free rider" problem). An extensive literature discusses the effect of free riders, concluding that common pool resources will inevitably fall into ruin. One of two solutions is usually offered to avoid this problem: centralized governmental regulation or privatization. Noting the numerous occasions in which common pool resources are managed successfully with neither centralized governmental control nor privatization, Ostrom argues for a third approach to resolving the problem of the commons: the design of durable cooperative institutions that are organized and governed by the resource users. In Governing the Commons she examines small-scale common-pool resources. Resource user groups examined range in size from 50-15,000 people who rely substantially on the common pool resource for their economic well-being. She has further

E. Paradis, J. Claude, K. Strimmer

Z. Michalewicz

R. Trivers

W. Hamilton

P. Erdos, A. Rényi

J. Stacey, J. Kramers

Motoo Kimura

K. Winemiller

W. Fitch

M. Zollo, S. Winter

This paper investigates the mechanisms through which organizations develop dynamic capabilities, defined as routinized activities directed to the development and adaptation of operating routines. It addresses the role of (1) experience accumulation, (2) knowledge articulation, and (3) knowledge codifi- cation processes in the evolution of dynamic, as well as operational, routines. The argument is made that dynamic capabilities are shaped by the coevolution of these learning mechanisms. At any point in time, firms adopt a mix of learning behaviors constituted by a semiautomatic accumulation of experience and by deliberate investments in knowledge articulation and codification activities. The relative effectiveness of these capability-building mechanisms is analyzed here as contingent upon selected features of the task to be learned, such as its frequency, homogeneity, and degree of causal ambiguity. Testable hypotheses about these effects are derived. Somewhat counterintuitive implications of the analysis include the relatively superior effectiveness of highly deliberate learning processes such as knowledge codification at lower levels of frequency and homogeneity of the organizational task, in contrast with common managerial practice.