Chemical and structural heterogeneity and the resulting interaction of coexisting phases can lead
to extraordinary behaviours in oxides, as observed in piezoelectric materials at morphotropic phase boundaries and relaxor ferroelectrics. However, such phenomena are rare in metallic alloys. Here we show that, by tuning the presence of structural heterogeneity in...
We present a survey of Nd isotopes measured from authigenic phases on surface sediments from the Arctic Ocean seafloor. Comparison with published dissolved water column Nd isotope distributions suggests that epsilon Nd from sediment leachates accurately represents bottom water circulation of the Arctic Ocean, with Atlantic (similar to 11 epsilon...
Many records provide the bases for a clearer understanding of the roles of climate regime shifts and short-term perturbations in ecosystem dynamics, hence fisheries responses. Too few have taken the long view of the role of humans in this "Grand Fugue". As one of many predators, it is imperative that...
Gramene (http://www.gramene.org) is a comparative genome mapping database for grasses and a community resource for rice. Rice, in addition to being an economically important crop, is also a model monocot for understanding other agronomically important grass genomes. Gramene replaces the existing AceDB database ‘RiceGenes’ with a relational database based on...
Gramene (http://www.gramene.org/) is a comparative genome database for cereal crops
and a community resource for rice. We are populating and curating Gramene with
annotated rice (Oryza sativa) genomic sequence data and associated biological information
including molecular markers, mutants, phenotypes, polymorphisms and Quantitative Trait
Loci (QTL). In order to support queries...
New seafloor mapping and sampling demonstrates that the eruption of the high-Ca boninites is clearly associated with rifting of the northern Tonga ridge and the northern Lau Basin at the northern termination of the Tonga Trench. There is very strong evidence for OIB plume related mantle sources involved in the...
We report new geochemical data for boninites and backarc basin-type basalts recovered from the northern termination of the Tonga trench and Lau Basin. Boninitic pillow lavas, ranging from high-Mg compositions to andesites and dacites, have been erupted within large submarine volcanic edifices (calderas and volcanoes) associated with active rifting of...
We report on a novel class of semiconductor metamaterials that employ a strongly anisotropic dielectric function to achieve negative refraction in the midinfrared region of the spectrum, ~8.5–13 μm. We present two types of metamaterials, layered highly doped/undoped heterostructures and quantum well superlattices that are highly anisotropic. Contrary to other...
Due to the high cost of precursor materials, complex oxides of 4d and 5d transition metals are under-studied compared to their 3d counterparts. Recent studies have shown that oxides containing heavier transition metals can exhibit exotic electronic states due to presence of strong spin-orbit coupling. The goal of this dissertation...
In this dissertation we study the electromagnetic properties of plasmonic metamaterials. We develop an analytical description to solve the fundamental problem of free-space scattering in planar plasmonic systems by utilizing anisotropic metamaterials. We show with exact numerical simulations that these manufactured materials do completely eliminate the scattering, and even in...