Can Pearlite form Outside of the Hultgren Extrapolation of the Ae3 and Acm Phase Boundaries?

It is usually assumed that ferrous pearlite can form only when the average austenite carbon concentration C lies between the extrapolated Ae3 (γ/α) and Acm (γ/θ) phase boundaries (the “Hultgren extrapolation”). This “mutual supersaturation” criterion for cooperative lamellar nucleation and growth is critically examined from a historical perspective and in light of recent experiments on coarse-grained hypoeutectoid steels which show pearlite formation outside the Hultgren extrapolation. This criterion, at least as interpreted in terms of the average austenite composition, is shown to be unnecessarily restrictive. The carbon fluxes evaluated from Brandt’s solution are sufficient to allow pearlite growth both inside and outside the Hultgren Extrapolation. As for the feasibility of the nucleation events leading to pearlite, the only criterion is that there are some local regions of austenite inside the Hultgren Extrapolation, even if the average austenite composition is outside.MMA and CC acknowledge financial support from Spanish Ministerio de Ciencia e Innovación in the form of a Coordinate Project (ENE2009-13766-C04-01). REH acknowledges support from the U.S. Department of Energy (contract DE-AC52-06NA25396).Peer Reviewe

Preserving accuracy in GenBank

GenBank, the public repository for nucleotide and protein sequences, is a critical resource for molecular biology, evolutionary biology, and ecology. While some attention has been drawn to sequence errors, common annotation errors also reduce the value of this database. In fact, for organisms such as fungi, which are notoriously difficult to identify, up to 20% of DNA sequence records may have erroneous lineage designations in GenBank. Gene function annotation in protein sequence databases is similarly error-prone. Because identity and function of new sequences are often determined by bioinformatic analyses, both types of errors are propagated into new accessions, leading to long-term degradation of the quality of the database. Currently, primary sequence data are annotated by the authors of those data, and can only be reannotated by the same authors. This is inefficient and unsustainable over the long term as authors eventually leave the field. Although it is possible to link third-party databases to GenBank records, this is a short-term solution that has little guarantee of permanence. Similarly, the current third-party annotation option in GenBank (TPA) complicates rather than solves the problem by creating an identical record with a new annotation, while leaving the original record unflagged and unlinked to the new record. Since the origin of public zoological and botanical specimen collections, an open system of cumulative annotation has evolved, whereby the original name is retained, but additional opinion is directly appended and used for filing and retrieval. This was needed as new specimens and analyses allowed for reevaluation of older specimens and the original depositors became unavailable. The time has come for the public sequence database to incorporate a community-curated, cumulative annotation process that allows third parties to improve the annotations of sequences when warranted by published peer-reviewed analyses.Fil: Bidartondo, Martin I.. Imperial College London; Reino Unido. Royal Botanic Gardens; Reino UnidoFil: Bruns, Thomas D.. University of California at Berkeley; Estados UnidosFil: Blackwell, Meredith. Louisiana State University; Estados UnidosFil: Edwards, Ivan. University of Michigan; Estados UnidosFil: Taylor, Andy F. S.. Swedish University of Agricultural Sciences; SueciaFil: Bianchinotti, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina. Universidad Nacional del Sur; ArgentinaFil: Padamsee, Mahajabeen. University of Minnesota; Estados UnidosFil: Callac, Philippe. Institut National de la Recherche Agronomique; FranciaFil: Lima, Nelson. Universidade do Minho; PortugalFil: White, Merlin M.. Boise State University; Estados UnidosFil: Barreau Daly, Camila. Centre National de la Recherche Scientifique; Francia. Institut National de la Recherche Agronomique; FranciaFil: Juncai, M. A.. Chinese Academy of Sciences; República de ChinaFil: Buyck, Bart. Museum National d'Histoire Naturelle; FranciaFil: Rabeler, Richard K.. University of Michigan; Estados UnidosFil: Liles, Mark R.. Auburn University; Estados UnidosFil: Estes, Dwayne. Austin Peay State University; Estados UnidosFil: Carter, Richard. Valdosta State University; Estados UnidosFil: Herr Jr., J. M.. University of South Carolina; Estados UnidosFil: Chandler, Gregory. University of North Carolina; Estados UnidosFil: Kerekes, Jennifer. University of California at Berkeley; Estados UnidosFil: Cruse Sanders, Jennifer. Salem College Herbarium; Estados UnidosFil: Galán Marquez, R.. Universidad de Alcalá; EspañaFil: Horak, Egon. Zurich Herbarium; SuizaFil: Fitzsimons, Michael. University of Chicago; Estados UnidosFil: Döering, Heidi. Royal Botanic Gardens; Reino UnidoFil: Yao, Su. China Center of Industrial Culture Collection; ChinaFil: Hynson, Nicole. University of California at Berkeley; Estados UnidosFil: Ryberg, Martin. University Goteborg; SueciaFil: Arnold, A. E.. University of Arizona; Estados UnidosFil: Hughes, Karen. University of Tennessee; Estados Unido