John R.N. Taylor

Bio: John R.N. Taylor is an academic researcher from University of Pretoria. The author has contributed to research in topics: Sorghum & Starch. The author has an hindex of 60, co-authored 313 publications receiving 12070 citations. Previous affiliations of John R.N. Taylor include Duke University & Council of Scientific and Industrial Research.

Linguistic Categorization: Prototypes in Linguistic Theory

Abstract: The categorization of colour the classical approach to categorization prototype categories linguistic and encyclopaedic knowledge polysemy and meaning chains category extension - metonymy and metaphor polysemous categories in morphology and syntax polysemous categories in intonation grammatical categories prototype categories in phonology the acquisition of categories.

MutS mediates heteroduplex loop formation by a translocation mechanism

Abstract: Interaction of Escherichia coli MutS and MutL with heteroduplex DNA has been visualized by electron microscopy. In a reaction dependent on ATP hydrolysis, complexes between a MutS dimer and a DNA heteroduplex are converted to protein-stabilized, alpha-shaped loop structures with the mismatch in most cases located within the DNA loop. Loop formation depends on ATP hydrolysis and loop size increases linearly with time at a rate of 370 base pairs/min in phosphate buffer and about 10,000 base pairs/min in the HEPES buffer used for repair assay. These observations suggest a translocation mechanism in which a MutS dimer bound to a mismatch subsequently leaves this site by ATP-dependent tracking or unidimensional movement that is in most cases bidirectional from the mispair. In view of the bidirectional capability of the methyl-directed pathway, this reaction may play a role in determination of heteroduplex orientation. The rate of MutS-mediated DNA loop growth is enhanced by MutL, and when both proteins are present, both are found at the base of alpha-loop structures, and both can remain associated with excision intermediates produced in later stages of the reaction.

Sorting Things Out: Classification and Its Consequences

Abstract: What do a seventeenth-century mortality table (whose causes of death include "fainted in a bath," "frighted," and "itch"); the identification of South Africans during apartheid as European, Asian, colored, or black; and the separation of machine- from hand-washables have in common? All are examples of classification -- the scaffolding of information infrastructures. In Sorting Things Out, Geoffrey C. Bowker and Susan Leigh Star explore the role of categories and standards in shaping the modern world. In a clear and lively style, they investigate a variety of classification systems, including the International Classification of Diseases, the Nursing Interventions Classification, race classification under apartheid in South Africa, and the classification of viruses and of tuberculosis. The authors emphasize the role of invisibility in the process by which classification orders human interaction. They examine how categories are made and kept invisible, and how people can change this invisibility when necessary. They also explore systems of classification as part of the built information environment. Much as an urban historian would review highway permits and zoning decisions to tell a city's story, the authors review archives of classification design to understand how decisions have been made. Sorting Things Out has a moral agenda, for each standard and category valorizes some point of view and silences another. Standards and classifications produce advantage or suffering. Jobs are made and lost; some regions benefit at the expense of others. How these choices are made and how we think about that process are at the moral and political core of this work. The book is an important empirical source for understanding the building of information infrastructures.

The Self-Organizing Map

Abstract: An overview of the self-organizing map algorithm, on which the papers in this issue are based, is presented in this article.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

Abstract: Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Informal learning in the workplace

Abstract: This paper focuses mainly on theoretical frameworks for understanding and investigating informal learning in the workplace, which have been developed through a series of large‐ and small‐scale projects. The main conclusions are included but readers are referred to other publications for more detailed accounts of individual projects. Two types of framework are discussed. The first group seeks to deconstruct the ‘key concepts’ of informal learning, learning from experience, tacit knowledge, transfer of learning and> intuitive practice to disclose the range of different phenomena that are embraced by these popular terms. The second group comprises frameworks for addressing the three central questions that pervaded the research programme: what is being learned, how is it being learned and what are the factors that influence the level and directions of the learning effort?