Proximity effects at ferromagnet-superconductor interfaces

We study proximity effects at ferromagnet superconductor interfaces by self-consistent numerical solution of the Bogoliubov-de Gennes equations for the continuum, without any approximations. Our procedures allow us to study systems with long superconducting coherence lengths. We obtain results for the pair potential, the pair amplitude, and the local density of states. We use these results to extract the relevant proximity lengths. We find that the superconducting correlations in the ferromagnet exhibit a damped oscillatory behavior that is reflected in both the pair amplitude and the local density of states. The characteristic length scale of these oscillations is approximately inversely proportional to the exchange field, and is independent of the superconducting coherence length in the range studied. We find the superconducting coherence length to be nearly independent of the ferromagnetic polarization.Comment: 13 Pages total. Compressed .eps figs might display poorly, but will print fin

Metabolic and miRNA Profiling of TMV Infected Plants Reveals Biphasic Temporal Changes

Plant viral infections induce changes including gene expression and metabolic components. Identification of metabolites and microRNAs (miRNAs) differing in abundance along infection may provide a broad view of the pathways involved in signaling and defense that orchestrate and execute the response in plant-pathogen interactions. We used a systemic approach by applying both liquid and gas chromatography coupled to mass spectrometry to determine the relative level of metabolites across the viral infection, together with a miRs profiling using a micro-array based procedure. Systemic changes in metabolites were characterized by a biphasic response after infection. The first phase, detected at one dpi, evidenced the action of a systemic signal since no virus was detected systemically. Several of the metabolites increased at this stage were hormone-related. miRs profiling after infection also revealed a biphasic alteration, showing miRs alteration at 5 dpi where no virus was detected systemically and a late phase correlating with virus accumulation. Correlation analyses revealed a massive increase in the density of correlation networks after infection indicating a complex reprogramming of the regulatory pathways, either in response to the plant defense mechanism or to the virus infection itself. Our data propose the involvement of a systemic signaling on early miRs alteration

Depositional styles in a low accommodation foreland basin setting: an example from the Basal Quartz (Lower Cretaceous), southern Alberta

The Lower Cretaceous Basal Quartz (BQ) of Southern Alberta (Townships 1–40, Ranges 1W5–5W5) can be informally divided into seven mappable units (A Sandstone, composed of the Regional A, Carmangay, Mesa IV, Valley and Terrace; Horsefly, BAT, Ellerslie). The study area is considered to be in an accommodation-limited setting due to the presence of multiple, closely spaced unconformities, and the general absence of marine deposits. Multiple levels of cyclicity exist in the BQ. There are two cycles of increasing-upward mineralogical and textural maturity, the first associated with the A Sandstone and the second associated with the Horsefly-BAT-Ellerslie succession. There are multiple southward marine transgressive events, both on the unit scale and on the cycle scale, indicative of a backstepping stacking geometry. The high resolution subdivision of the BQ allows for the recognition of changing BQ paleodrainage through time. There is both a progressive spatial and stratigraphic change in incised valley organization, from thin and wide valley forms in the south and at the base of the cycles, to thicker, narrower and more deeply cut systems toward the northwest and top of the cycles. In addition, there is spatial variation in tributary systems for the upper cycle, from no tributaries associated with the thin, wide valley forms associated with the Horsefly, to narrow and thin tributaries in the BAT south of the Vulcan Low, deeply cut complex tributary systems across the Vulcan Low, and linear deep tributaries north of the Vulcan Low for both the BAT and Ellerslie. The style of depositional fill also changes stratigraphically and spatially, from braided to coarse meandering "sheet" deposits south of the Vulcan Low associated with the Carmangay and Horsefly, and low accommodation Valley and Terrace and BAT north of the Vulcan Low; meandering deposits associated with the low accommodation Mesa IV, and higher accommodation Valley and Terrace, Horsefly and BAT; and fluvial-estuarine deposits associated with the Valley and Terrace, BAT and Ellerslie north of the Vulcan Low in higher accommodation setting. The dominant control on the BQ depositional patterns is the interplay between eustasy and heterogeneous basement subsidence. The tectonic influences on sedimentation are most obvious in the sediments immediately overlying long-duration unconformities. Fluvial erosion on the unconformity surface amplifies the tectonic signal by accentuating the technically produced relief in a low accommodation setting. The accommodation-limited conditions occurring during BQ deposition resulted in sequence boundaries amalgamating on the interfluve, and it is only by detailed correlation and petrographic analysis that BQ units can be differentiated. CSPG© 2002, reprinted by permission of CSPG whose permission is required for further use