Probing the Locally Generated Even and Odd Order Nonlinearity in Y-Ba-Cu-O and Tl-Ba-Ca-Cu-O (2212) Microwave Resonators around TC

Spatial scanning of the synchronously generated 2nd and 3rd order intermodulation distortion in superconducting resonators uncovers local nonlinearity hot spots, and possible time reversal symmetry breaking, using a simple probe fashioned from coaxial cable. It is clear that even and odd order nonlinearity in these samples do not share the same physical origins, as their temperature and static magnetic field dependences are quite different. 2nd order intermodulation distortion (IMD) remains strong in these measurements as the temperature continues to drop below TC to 77K even though the 3rd order peaks near TC and becomes smaller at lower temperature as predicted by the nonlinear Meissner effect. Both YBa2Cu3O7 and Tl2Ba2CaCu2O8 resonators of the same structure exhibit similar temperature dependence in the 2nd order with 2nd order remaining high at lower temperature. The YBa2Cu3O7 sample has lower 3rd order IMD with a pronounced peak at TC

The Knowledge of the Grid: A Grid Ontology

This paper presents a knowledge architecture and set of ontologies that can be used as the foundation to facilitate the matching of abstract resource requests to services and resources, to determine the functional equivalence of Grid middle wares and deployments and to allow the description of ‘hybrid’ compound Grids composed of individual heterogeneous Grids. This is necessary as in all these cases what is required is mediation between different views or descriptions of Grids, which requires a formal reference vocabulary. We present a framework and ontologies for achieving this

Parallel functional differentiation of an invasive annual plant on two continents.

Rapid local adaptation frequently occurs during the spread of invading species. It remains unclear, however, how consistent, and therefore potentially predictable, such patterns of local adaptation are. One approach to this question is to measure patterns of local differentiation in functional traits and plasticity levels in invasive species in multiple regions. Finding consistent patterns of local differentiation in replicate regions suggests that these patterns are adaptive. Further, this outcome indicates that the invading species likely responds predictably to selection along environmental gradients, even though standing genetic variation is likely to have been reduced during introduction. We studied local differentiation in the invasive annual plant Erodium cicutarium in two invaded regions, California and Chile. We collected seeds from across strong gradients in precipitation and temperature in Mediterranean-climate parts of the two regions (10 populations per region). We grew seeds from maternal families from these populations through two generations and exposed the second generation to contrasting levels of water and nutrient availability. We measured growth, flowering time and leaf functional traits across these treatments to obtain trait means and plasticity measures. We found strong differentiation among populations in all traits. Plants from drier environments flowered earlier, were less plastic in flowering time and reached greater size in all treatments. Correlations among traits within regions suggested a coordinated evolutionary response along environmental gradients associated with growing season length. There was little divergence in traits and trait intercorrelations between regions, but strongly parallel divergence in traits within regions. Similar, statistically consistent patterns of local trait differentiation across two regions suggest that local adaptation to environmental gradients has aided the spread of this invasive species, and that the formation of ecotypes in newly invaded environments has been relatively consistent and predictable

In--out intermittency in PDE and ODE models

We find concrete evidence for a recently discovered form of intermittency, referred to as in--out intermittency, in both PDE and ODE models of mean field dynamos. This type of intermittency (introduced in Ashwin et al 1999) occurs in systems with invariant submanifolds and, as opposed to on--off intermittency which can also occur in skew product systems, it requires an absence of skew product structure. By this we mean that the dynamics on the attractor intermittent to the invariant manifold cannot be expressed simply as the dynamics on the invariant subspace forcing the transverse dynamics; the transverse dynamics will alter that tangential to the invariant subspace when one is far enough away from the invariant manifold. Since general systems with invariant submanifolds are not likely to have skew product structure, this type of behaviour may be of physical relevance in a variety of dynamical settings. The models employed here to demonstrate in--out intermittency are axisymmetric mean--field dynamo models which are often used to study the observed large scale magnetic variability in the Sun and solar-type stars. The occurrence of this type of intermittency in such models may be of interest in understanding some aspects of such variabilities.Comment: To be published in Chaos, June 2001, also available at http://www.eurico.web.co

Storing and sharing wisdom and traditional knowledge in the library

Traditional library practice focuses on print collections and developing collections of materials that have been published, which means the documents have gone through some kind of review or vetting process. This practice leaves a wide swath of potential knowledge out of the collection. For example, indigenous knowledge, beliefs, and experience are different, in that they do not undergo the same review or vetting process; we might refer to these types of content as wisdom. Non-print collections, such as collections of recorded oral histories, represent less traditional forms of knowledge. Human libraries push the boundaries further in the quest to integrate wisdom and lived experience into library collections. This paper delineates the relationship between wisdom and knowledge that arose during a phenomenological study of the everyday information practices of Kenyan university women. The women were asked to photograph everyday events from their life and describe what they saw. One finding was a divergent presentation of wisdom and knowledge. Because the women were describing this in relation to their education, we assert that this demonstrates a need to reconsider positivist assumptions in library science, bringing what the women called wisdom into the stacks. How, though, can wisdom be stored and shared?Includes bibliographical references