319 research outputs found
Spatial multimode structure of atom-generated squeezed light
We investigated the spatial distribution of quantum fluctuations in a squeezed vacuum field, generated via polarization self-rotation (PSR) interaction of an ensemble of Rb atoms and a strong near-resonant linearly polarized laser field. We found that the noise suppression is greatly effected by the transverse profile of a spatial mask, placed in both the squeezed field and the local oscillator, as well as its position along the focused beam near the focal point. These observations indicate the spatial multimode structure of the squeezed vacuum field. We have developed a theoretical model that describes the generation of higher-order Laguerre-Gauss modes as a result of PSR light-atom interaction. The prediction of this model is in a good qualitative agreement with the experimental measurements
Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.
BACKGROUND: Electrophysiological data suggest that cardiac KATP channels consist of Kir6.2 and SUR2A subunits, but the distribution of these (and other KATP channel subunits) is poorly defined. We examined the localization of each of the KATP channel subunits in the mouse and rat heart. RESULTS: Immunohistochemistry of cardiac cryosections demonstrate Kir6.1 protein to be expressed in ventricular myocytes, as well as in the smooth muscle and endothelial cells of coronary resistance vessels. Endothelial capillaries also stained positive for Kir6.1 protein. Kir6.2 protein expression was found predominantly in ventricular myocytes and also in endothelial cells, but not in smooth muscle cells. SUR1 subunits are strongly expressed at the sarcolemmal surface of ventricular myocytes (but not in the coronary vasculature), whereas SUR2 protein was found to be localized predominantly in cardiac myocytes and coronary vessels (mostly in smaller vessels). Immunocytochemistry of isolated ventricular myocytes shows co-localization of Kir6.2 and SUR2 proteins in a striated sarcomeric pattern, suggesting t-tubular expression of these proteins. Both Kir6.1 and SUR1 subunits were found to express strongly at the sarcolemma. The role(s) of these subunits in cardiomyocytes remain to be defined and may require a reassessment of the molecular nature of ventricular KATP channels. CONCLUSIONS: Collectively, our data demonstrate unique cellular and subcellular KATP channel subunit expression patterns in the heart. These results suggest distinct roles for KATP channel subunits in diverse cardiac structures
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Summary of rheological studies related to HWVP slurries
Numerous studies (Section 8) have,addressed the Theological properties of simulated process slurries at the Savannah River Laboratory for the Defense Waste Processing Facility and at Pacific Northwest Laboratory`(PNL) for the Hanford Waste Vitrification Plant (HWVP). These studies were reviewed to summarize existing data applicable to HWVP design. The reviewers determined that the existing data provide important information on the effects of feed variability, solids loading, temperature, formating, pH, and scale-up. However, these data cannot serve as a basis for fundamental slurry transport calculations because data are not reported in sufficient detail over a range of shear rates and in appropriate terms to be sufficient for transport calculations
Optimal static pricing for a tree network
We study the static pricing problem for a network service provider in a loss system with a tree structure. In the network, multiple classes share a common inbound link and then have dedicated outbound links. The motivation is from a company that sells phone cards and needs to price calls to different destinations. We characterize the optimal static prices in order to maximize the steady-state revenue. We report new structural findings as well as alternative proofs for some known results. We compare the optimal static prices versus prices that are asymptotically optimal, and through a set of illustrative numerical examples we show that in certain cases the loss in revenue can be significant. Finally, we show that static prices obtained using the reduced load approximation of the blocking probabilities can be easily obtained and have near-optimal performance, which makes them more attractive for applications.Massachusetts Institute of Technology. Center for Digital BusinessUnited States. Office of Naval Research (Contract N00014-95-1-0232)United States. Office of Naval Research (Contract N00014-01-1-0146)National Science Foundation (U.S.) (Contract DMI-9732795)National Science Foundation (U.S.) (Contract DMI-0085683)National Science Foundation (U.S.) (Contract DMI-0245352
Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)
We report the discovery of an extensive system of scattered light echo
arclets associated with the recent supernovae in the local neighbourhood of the
Milky Way: Tycho (SN 1572) and Cassiopeia A. Existing work suggests that the
Tycho SN was a thermonuclear explosion while the Cas A supernova was a core
collapse explosion. Precise classifications according to modern nomenclature
require spectra of the outburst light. In the case of ancient SNe, this can
only be done with spectroscopy of their light echo, where the discovery of the
light echoes from the outburst light is the first step. Adjacent light echo
positions suggest that Cas A and Tycho may share common scattering dust
structures. If so, it is possible to measure precise distances between
historical Galactic supernovae. On-going surveys that alert on the development
of bright scattered-light echo features have the potential to reveal detailed
spectroscopic information for many recent Galactic supernovae, both directly
visible and obscured by dust in the Galactic plane.Comment: 4 pages, 4 color figures, accepted for publication in ApJ
Progress report no. 2
Statement of responsibility on title-page reads: Editors: I.A. Forbes, M.J. Driscoll, N.C. Rasmussen, D.D. Lanning and I. Kaplan; Contributors: S.T. Brewer, G.J. Brown, P.DeLaquil, III, M.J. Driscoll, I.A. Forbes, C.W. Forsberg, E.P. Gyftopoulos, P.L. Hendrick, C.S. Kang, I. Kaplan, J.L. Klucar, D.D. Lanning, T.C. Leung, E.A. Mason, N.R. Ortiz, N.A. Passman, N.C. Rasmussen, I.C. Rickard, V.C. Rogers, G.E. Sullivan, A.T. Supple, and C. P. TzanosIncludes bibliographical referencesProgress report; June 30, 1971U.S. Atomic Energy Commission contract AT(11-1)306
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