Darwin Core: An Evolving Community-Developed Biodiversity Data Standard

Biodiversity data derive from myriad sources stored in various formats on many distinct hardware and software platforms. An essential step towards understanding global patterns of biodiversity is to provide a standardized view of these heterogeneous data sources to improve interoperability. Fundamental to this advance are definitions of common terms. This paper describes the evolution and development of Darwin Core, a data standard for publishing and integrating biodiversity information. We focus on the categories of terms that define the standard, differences between simple and relational Darwin Core, how the standard has been implemented, and the community processes that are essential for maintenance and growth of the standard. We present case-study extensions of the Darwin Core into new research communities, including metagenomics and genetic resources. We close by showing how Darwin Core records are integrated to create new knowledge products documenting species distributions and changes due to environmental perturbations

Challenges in Developing High Performance Al-Li Alloys

The goal of replacing \u27conventional\u27 Al alloys with Al-Li alloys to reduce weight of aerospace structures has had only limited success to date, despite one of the largest alloy-development programs ever undertaken. One of the reasons being, for some product forms and crack-plane orientations, fracture toughness is lower compared with conventional Al alloys due to a greater propensity for low-energy intergranular fracture. Proposed explanations for brittle intergranular fracture include: (i) planar slip resultingin high stresses where slip bands impinge on grain-boundaries, (ii) embrittlement due to alkali-metal-impurity phases, and (iii) grain-boundary structural changes associated with segregation of lithium. The present paper reviews evidence for and against these proposed mechanisms based on (i) studies of 8090 and 2090 alloys, and the more recently developed 2297 alloy, and (ii) comparisons of fracture of these alloys with other materials that exhibit grain-boundary weakness. It appears that lithium segregation to grain boundaries is the prime cause of low-energy intergranular fracturein Al-Li alloys. Embrittlement by alkali-metal impurities is not important providing that impurity levels are less than about 5 ppm (as is the case for most commercially produced alloys). Planar slip and other factors probably play only a minor role

Communism in retrospect: The rhetoric of historical representation and writing the collective memory of recent past

This article was published in the journal, Memory Studies [Sage © The Author] and the definitive version is available at: http://dx.doi.org/10.1177/1750698011434042Using a case study of official representation of communism in Romania, this article addresses the rhetoric of historical representation and some of the ways in which the collective memory of communism is managed in the context of how post-communist democracies reckon with former regimes. It specifically centres on the public accomplishment of coming to terms with the past in the ‘Tisma˘neanu Report’ condemning communism in Romania. Using an ethnomethodologically inspired critical analysis, the article examines how the report and texts supporting it address the issue of how to take the communist era into public consciousness. The shaping of a specific representation of communism and the making of political-moral judgments in the report is legitimated by (1) treating communism as a category of the macro-social and textually mediated reality, (2) constructing the need for a scientific approach, and (3) conceiving communism as Other, alien to national identity and national interest. General implications for the substance and meaningfulness of coming to terms with recent history are discussed