Collective Edge Excitations In The Quantum Hall Regime: Edge Helicons And Landau-level Structure

Based on a microscopic evaluation of the local current density, a treatment of edge magnetoplasmons (EMP) is presented for confining potentials that allow Landau level (LL) flattening to be neglected. Mode damping due to electron-phonon interaction is evaluated. For nu=1, 2 there exist independent modes spatially symmetric or antisymmetric with respect to the edge. Certain modes, changing shape during propagation, are nearly undamped even for very strong dissipation and are termed edge helicons. For nu > 2 inter-LL Coulomb coupling leads to a strong repulsion of the decoupled LL fundamental modes. The theory agrees well with recent experiments.Comment: 4 pages in Latex/Revtex/two-column format, 3 ps figure

The effect of walnut intake on factors related to prostate and vascular health in older men

<p>Abstract</p> <p>Background</p> <p>Tocopherols may protect against prostate cancer and cardiovascular disease (CVD).</p> <p>Methods</p> <p>We assessed the effect of walnuts, which are rich in tocopherols, on markers of prostate and vascular health in men at risk for prostate cancer. We conducted an 8-week walnut supplement study to examine effects of walnuts on serum tocopherols and prostate specific antigen (PSA). Subjects (<it>n </it>= 21) consumed (in random order) their usual diet +/- a walnut supplement (75 g/d) that was isocalorically incorporated in their habitual diets. Prior to the supplement study, 5 fasted subjects participated in an acute timecourse experiment and had blood taken at baseline and 1, 2, 4, and 8 h after consuming walnuts (75 g).</p> <p>Results</p> <p>During the timecourse experiment, triglycerides peaked at 4 h, and gamma-tocopherol (γ-T) increased from 4 to 8 h. Triglyceride – normalized γ-T was two-fold higher (<it>P </it>= 0.01) after 8 versus 4 h. In the supplement study, change from baseline was +0.83 ± 0.52 μmol/L for γ-T, -2.65 ± 1.30 μmol/L for alpha-tocopherol (α-T) and -3.49 ± 1.99 for the tocopherol ratio (α-T: γ-T). A linear mixed model showed that, although PSA did not change, the ratio of free PSA:total PSA increased and approached significance (P = 0.07). The α-T: γ-T ratio decreased significantly (<it>P </it>= 0.01), partly reflecting an increase in serum γ-T, which approached significance (<it>P </it>= 0.08).</p> <p>Conclusion</p> <p>The significant decrease in the α-T: γ-T ratio with an increase in serum γ-T and a trend towards an increase in the ratio of free PSA:total PSA following the 8-week supplement study suggest that walnuts may improve biomarkers of prostate and vascular status.</p

Ion flow in a zeolitic imidazolate framework results in ionic diode phenomena

Ionic transport (for applications in nanofluidics or membranes) and “ionic diode” phenomena in a zeolitic imidazolate framework (ZIF-8) are investigated by directly growing the framework from aqueous Zn2+ and 2-methylimidazole as an “asymmetric plug” into a 20 ?m diameter pore in a ca. 6 ?m thin poly-ethylene-terephthalate (PET) film

Repulsion of Single-well Fundamental Edge Magnetoplasmons in Double Quantum Wells

A {\it microscopic} treatment of fundamental edge magnetoplasmons (EMPs) along the edge of a double quantum well (DQW) is presented for strong magnetic fields, low temperatures, and total filling factor \nu=2. It is valid for lateral confining potentials that Landau level (LL) flattening can be neglected. The cyclotron and Zeeman energies are assumed larger than the DQW energy splitting \sqrt{\Delta^2 +4T^2}, where \Delta is the splitting of the isolated wells and T the tunneling matrix element. %hen calculated unperturbed density profile is sharp at the edge. Using a random-phase approximation (RPA), which includes local and nonlocal contributions to the current density, it is shown that for negligible tunnel coupling 2T << \Delta the inter-well Coulomb coupling leads to two DQW fundamental EMPs which are strongly renormalized in comparison with the decoupled, single-well fundamental EMP. These DQW modes can be modified further upon varying the inter-well distance d, along the z axis, and/or the separation of the wells' edges \Delta y along the y axis. The charge profile of the {\it fast} and {\it slow} DQW mode varies, respectively, in an {\it acoustic} and {\it optical} manner along the y axis and is not smooth on the \ell_{0} scale. For strong tunneling \Delta\alt 2T these DQW modes are essentially modified when \Delta is changed by applying a transverse electric field to the DQW.Comment: Text 18 pages in Latex/Revtex/Preprint format, 2 Postscript figure

The USNO-B Catalog

USNO-B is an all-sky catalog that presents positions, proper motions, magnitudes in various optical passbands, and star/galaxy estimators for 1,042,618,261 objects derived from 3,643,201,733 separate observations. The data were obtained from scans of 7,435 Schmidt plates taken for the various sky surveys during the last 50 years. USNO-B1.0 is believed to provide all-sky coverage, completeness down to V = 21, 0.2 arcsecond astrometric accuracy at J2000, 0.3 magnitude photometric accuracy in up to five colors, and 85% accuracy for distinguishing stars from non-stellar objects. A brief discussion of various issues is given here, but the actual data are available from http://www.nofs.navy.mil and other sites.Comment: Accepted by Astronomical Journa